Literatura académica sobre el tema "L-form bacteria"
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Artículos de revistas sobre el tema "L-form bacteria"
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Errington, Jeff. "L-form bacteria, cell walls and the origins of life". Open Biology 3, n.º 1 (enero de 2013): 120143. http://dx.doi.org/10.1098/rsob.120143.
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The peptidoglycan wall is a defining feature of bacterial cells and was probably already present in their last common ancestor. L-forms are bacterial variants that lack a cell wall and divide by a variety of processes involving membrane blebbing, tubulation, vesiculation and fission. Their unusual mode of proliferation provides a model for primitive cells and is reminiscent of recently developed in vitro vesicle reproduction processes. Invention of the cell wall may have underpinned the explosion of bacterial life on the Earth. Later innovations in cell envelope structure, particularly the emergence of the outer membrane of Gram-negative bacteria, possibly in an early endospore former, seem to have spurned further major evolutionary radiations. Comparative studies of bacterial cell envelope structure may help to resolve the early key steps in evolutionary development of the bacterial domain of life.
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Errington, Jeff, Katarzyna Mickiewicz, Yoshikazu Kawai y Ling Juan Wu. "L-form bacteria, chronic diseases and the origins of life". Philosophical Transactions of the Royal Society B: Biological Sciences 371, n.º 1707 (5 de noviembre de 2016): 20150494. http://dx.doi.org/10.1098/rstb.2015.0494.
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The peptidoglycan cell wall is widely conserved across the bacterial domain, suggesting that it appeared early in the evolution of bacteria. It is normally essential but under certain conditions wall-deficient or ‘L-form’ bacteria can be isolated. In Bacillus subtilis this normally requires two genetic changes. The first, exemplified by mutations shutting down wall precursor synthesis, works by increasing membrane synthesis. This promotes the unusual form of proliferation used by L-forms, involving a range of relatively disorganized membrane blebbing or vesiculation events. The secondary class of mutations probably work by relieving oxidative stress that L-forms may incur due to their unbalanced metabolism. Repression or inhibition of cell wall precursor synthesis can stimulate the L-form transition in a wide range of bacteria, of both Gram-positive and -negative lineages. L-forms are completely resistant to most antibiotics working specifically on cell wall synthesis, such as penicillins and cephalosporins, consistent with the many reports of their involvement in various chronic diseases. They are potentially important in biotechnology, because lack of a wall can be advantageous in a range of production or strain improvement applications. Finally, L-forms provide an interesting model system for studying early steps in the evolution of cellular life. This article is part of the themed issue ‘The new bacteriology’.
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Daulagala, PWHKP y EJ Allan. "Induction of L-form Bacteria from Bacillus thuringiensis". Ceylon Journal of Science (Biological Sciences) 41, n.º 2 (3 de abril de 2013): 137. http://dx.doi.org/10.4038/cjsbs.v41i2.5383.
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Osawa, Masaki y Harold P. Erickson. "L form bacteria growth in low-osmolality medium". Microbiology 165, n.º 8 (1 de agosto de 2019): 842–51. http://dx.doi.org/10.1099/mic.0.000799.
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Grichko, Varvara P. y Bernard R. Glick. "The potential of L-form bacteria in biotechnology". Canadian Journal of Chemical Engineering 77, n.º 5 (octubre de 1999): 973–77. http://dx.doi.org/10.1002/cjce.5450770526.
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Mokhtar, Norfaniza, Zhameir Shafiq Mohd Ilias, Husnul Azan Tajarudin y Megat Azmi Megat Johari. "Optimization of HCO3- Production Reflect to CaСo3 Precipitation for Self-Healing by Bacillus sphaericus". Applied Mechanics and Materials 802 (octubre de 2015): 549–54. http://dx.doi.org/10.4028/www.scientific.net/amm.802.549.
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Bacteria are able to perform metabolic activities which promote the precipitation of calcium carbonate in the form of calcite. Bacillus Sphaericus was used in this study, which is an ureolytic bacteria that can precipitate calcium carbonate in its environment by the decomposition of urea into ammonium and carbonate. The bacterial degradation of urea basically increases the pH and promotes the microbial deposition of carbonate as calcium carbonate. In this research, the capability of bacteria to influence the formation of HCO3- by the production of urease enzyme was investigated. Results of growth rate and characteristics of bacteria showed that 20g/L of urea concentration was able to provide a good environment for bacteria with sufficient amount of nutrient to survive. The formation of HCO3- was parallel with NH3 production where the formation of HCO3- increased slowly as the ammonia production decreased. Urea degradation with suitable concentration of urea by 20g/L may form high HCO3- compared to 25g/L urea concentration. The results from the experimental works indicated that the optimal urea concentration was 20g/L.
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Errington, Jeff. "Cell wall-deficient, L-form bacteria in the 21st century: a personal perspective". Biochemical Society Transactions 45, n.º 2 (13 de abril de 2017): 287–95. http://dx.doi.org/10.1042/bst20160435.
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The peptidoglycan (PG) cell wall is a defining feature of the bacteria. It emerged very early in evolution and must have contributed significantly to the success of these organisms. The wall features prominently in our thinking about bacterial cell function, and its synthesis involves the action of several dozen proteins that are normally essential for viability. Surprisingly, it turns out to be relatively simple to generate bacterial genetic variants called L-forms that completely lack PG. They grow robustly provided that lack of the cell wall is compensated for by an osmoprotective growth medium. Although their existence has been noted and studied on and off for many decades, it is only recently that modern molecular and cellular methods have been applied to L-forms. We used Bacillus subtilis as an experimental model to understand the molecular basis for the L-form switch. Key findings included the discovery that L-forms use an unusual blebbing, or tubulation and scission mechanism to proliferate. This mechanism is completely independent of the normal FtsZ-based division machinery and seems to require only an increased rate of membrane synthesis, leading to an increased surface area-to-volume ratio. Antibiotics that block cell wall precursor synthesis, such as phosphomycin, efficiently induce the L-form switch without the need for genetic change. The same antibiotics turned out to induce a similar L-form switch in a wide range of bacteria, including Escherichia coli, in which we showed that proliferation was again FtsZ-independent. Aside from further basic science, future work on L-forms is likely to focus on their possible role in chronic or recurrent infections, their use as a model in studies of the origins of life, and possibly, biotechnological applications.
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Ibrahim, Arsyik, Aditya Fridayanti y Fila Delvia. "ISOLASI DAN IDENTIFIKASI BAKTERI ASAM LAKTAT (BAL) DARI BUAH MANGGA (Mangifera indica L.)". Jurnal Ilmiah Manuntung 1, n.º 2 (26 de enero de 2017): 159. http://dx.doi.org/10.51352/jim.v1i2.29.
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The research has been done for the isolation and identification of lactic acid bacteria (LAB) from mango (Mangifera indica L.). This research aimed to isolated of lactic acid bacteria that is in mango (Mangifera indica L.) and determine the characteristics of lactic acid bacteria isolate (LAB) of mango (Mangifera indica L.). The method used is spoiled technique of mango (Mangifera indica L.) and isolation using selective media MRS Broth and MRS Agar. The identification isolate of lactic acid bacteria (LAB) used methods macroscopically and microscopically with indirect coloring, gram staining and used biochemical with katalase testing. The results obtained in the form of characteristic isolate of lactic acid bacteria displayed form of bacteria with circle, smooth surface, curve, entire side and white. The microscopically displayed stick form of bacteria and purple with gram coloring
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Xu, Yuanyuan, Baoping Zhang, Li Wang, Tao Jing, Jing Chen, Xiaogang Xu, Wenhong Zhang, Ying Zhang y Jian Han. "Unusual features and molecular pathways of Staphylococcus aureus L-form bacteria". Microbial Pathogenesis 140 (marzo de 2020): 103970. http://dx.doi.org/10.1016/j.micpath.2020.103970.
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Innes, C. M. J. y E. J. Allan. "Induction, growth and antibiotic production of Streptomyces viridifaciens L-form bacteria". Journal of Applied Microbiology 90, n.º 3 (2 de marzo de 2001): 301–8. http://dx.doi.org/10.1046/j.1365-2672.2001.01243.x.
Texto completoTesis sobre el tema "L-form bacteria"
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Daulagala, P. W. H. K. Priyadarshani. "Chitinases, L-form bacteria and plant symbioses". Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327009.
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Mantovani, Elenice. "Identificação do agente etiológico da Doença de Lyme-símile brasileira (Síndrome Baggio-Yoshinari)". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/5/5164/tde-04112010-145154/.
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A Doença de Lyme-símile brasileira ou Síndrome Baggio-Yoshinari (SBY) é uma zoonose emergente, transmitida por carrapatos e até o momento, de descrição restrita ao território brasileiro. O agente etiológico da SBY era desconhecido até o presente trabalho. O objetivo principal do estudo foi identificar a etiologia da SBY. Foi selecionado 2 grupos de pacientes: grupo A (n=68) composto por pacientes com suspeita diagnóstica de SBY, a maioria na fase latente da doença; grupo B (n=10), composto por pacientes com diagnóstico de SBY, que apresentaram obrigatoriamente eritema migratório e que encontravam-se sintomáticos no momento da coleta. Foi utilizado também um grupo controle composto por indivíduos saudáveis e com epidemiologia negativa (n=50). Amostras de sangue foram coletadas para a realização de sorologias, culturas, análises microscópicas (óptica e eletrônica) e reação de cadeia da polimerase (PCR) para diferentes micro-organismos (Mycoplasma spp, Chlamydia spp e Borrelia spp). Além disso, foi realizado um estudo preliminar, através da PCR para Borrelia spp em 47 amostras de carrapatos oriundos de áreas de risco do Espírito Santo (sendo 17 Rhipicephalus microplus e 30 Rhipicephalus sanguineus), e amostras de sangue total de 27 bovinos e 26 equinos, animais estes oriundos da Universidade Federal Rural do Rio de Janeiro. Os resultados mostraram que a SBY não se trata de uma zoonose causada por um conjunto de micro-organismos como pensado inicialmente e sim pela Borrelia burgdorferi sensu lato. Descoberta essa que foi possível empregando-se novos primers amplificadores do principal gene envolvido na síntese do gancho flagelar da Borrelia, chamado flgE. A positividade para flgE foi confirmada em 6 pacientes do grupo B, 2 carrapatos, 1 bovino e 1 equino, os quais apresentaram homologia de 99% com o gene da proteína do gancho flagelar da Borrelia burgdorferi (flgE) depositado no GenBank (L43849). Esta importante descoberta, associada às pesquisas anteriores, permitiu definir a SBY como zoonose emergente e própria do país, causada pela bactéria B. burgdorferi na apresentação morfológica atípica, transmitida por carrapatos não pertencentes ao complexo Ixodes ricinus, responsável por manifestações clínicas semelhantes à Doença de Lyme, exceto pela grande frequência de sintomas recorrentesBrazilian Lyme disease-like illness (BLDL) or Baggio-Yoshinari Syndrome (BYS) is an emerging zoonosis, transmitted by ticks and so far, restricted to the description of the Brazilian territory. The causative agent of BYS was unknown until now. The main objective of this study was to identify the etiology of BYS. We have selected two groups of patients: group A (n = 68) consisting of patients suspected of BYS, mostly in the latent stage of disease; group B (n = 10), composed of patients diagnosed with BYS, who had compulsorily erythema migrans and that were symptomatic at the time of blood collection. We also used a control group composed of healthy individuals with negative epidemiology (n = 50). Blood samples were collected, in which we performed serology, cultures, microscopic analysis (optical and electron) and polymerase chain reaction (PCR) for different microorganisms (Mycoplasma spp, Chlamydia spp and Borrelia spp). In addition, a preliminary study was conducted by PCR for Borrelia spp in 47 samples of ticks from risk areas at Espirito Santo State (being 17 Rhipicephalus microplus and 30 Rhipicephalus sanguineus), 27 cattle and 26 horses, being these animals from the Universidade Federal Rural do Rio de Janeiro. The results showed that BYS is not a zoonosis caused by a set of microorganisms as initially thought, but by Borrelia burgdorferi sensu lato. These findings were possible after employing new primers that are able to amplify portions of the main genes involved in the synthesis of the Borrelia flagellar hook protein, called flgE. We confirmed positivity for the flgE in 6 patients from group B, 2 ticks, a cow, and a horse, which showed 99% homology with the gene of Borrelia burgdorferi flagellar hook protein (flgE) deposited in GenBank (L43849). This important discovery, coupled with previous research, helped to define BYS as an emerging zoonosis particular from Brazil, caused by B. burgdorferi of atypical morphologic presentation, transmitted by ticks outside the Ixodes ricinus complex, responsible for clinical signs similar to Lyme disease, except for the high frequency of relapsing symptoms
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Buhariwalla, Hutokshi Keki. "Bacterial L-form associations with plants". Thesis, University of Aberdeen, 1993. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU542133.
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L-form bacteria can be induced in vitro by the treatment of cell walled bacteria with compounds which suppress cell wall synthesis. It has previously been demonstrated that a variety of bacterial L-forms could invade plant-cells and establish a novel symbiotic association within the plant-host, with no apparent host limitations. Such associations were mainly recognised by direct microscopy and immunological detection techniques. The main aim of this project was to develop and optimise a reporter gene system for the detection of genetically modified Bacillus subtilis and Pseudomonas syringae pv. phaseolicola L-form associations in planta . Associations were attempted between B.subtilis L-forms chromosomally marked with -glucuronidase ( gus ) genes and Chinese cabbage. PCR detection indicated the lack of stable plant-L-form associations. Plasmid vectors encoding the genes for luciferase ( lux ) from Vibrio fischeri were introduced into the French bean pathogen Pseudomonas syringae pv. phaseolicola and L-forms were then induced. Symbiotic associations were established between these lux -modified L-forms and Chinese cabbage. Associations were detected at 7 days after germination by PCR amplification of a lux -gene fragment, using 100 ng of total plant DNA as a template. In addition the distribution of lux -modified P.syringae L-forms into various tissues of the plant was monitored using PCR amplification of the lux -gene and Staphylococcus agglutination, these techniques provided information on the presence of DNA and protein-antigens respectively. In contrast, bioluminescence, determined by luminometry, X-ray film imaging and charge-coupled device enhanced microscopy, permitted the detection of intact, active and viable populations of P.syringae L-forms. The bioluminescence based detection assays were non destructive and rapid (5 min) providing direct visualisation of microbial activity in planta . The data suggests that the distribution of lux -modified L-forms is non-uniform, predominantly in the roots and primary leaves of 14 day old Chinese cabbage.
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Muiry, Jennifer Anne Ross. "The bacterial transport systems for L-rhamnose and L-fucose". Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315190.
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Gibb, Andrew. "Studies on the morphological variants (L-forms) of the bacterial fishpathogen aeromonas salmonicida". Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1421.
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Balimponya, Elias George. "Application of Genomic Selection and Association Mapping to Breeding for Resistance to Rice Blast and Bacterial Blight of Rice (Oryza sativa L.)". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449138999.
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Guo, Yufang. "Quantitative genetic analysis for flowering time in primitive Upland cotton, Gossypium hirsutum L., and chromosome assignment of BAC-derived SSR markers". Diss., Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-11062007-142438.
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Ben, Chobba Kadri Inès. "Élaboration et mise en oeuvre d'une approche de caractérisation systémique d'un agent étiologique émergent à fort impact économique et de moyens de lutte biologique : application à la maladie de la feuille cassante du palmier dattier (Phoenix dactylifera L.)". Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20077.
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La Maladie de la Feuille Cassante du Palmier dattier (Phoenix dactylifera L.) constitue un cas d'émergence d'une maladie à fort impact économique causée par un agent étiologique inconnu. Notre stratégie a visé à élaborer une approche sans à priori de l'émergence pouvant être transposée à n'importe quelle situation de ce type. En nous appuyant sur des caractérisations successives des compartiments viraux, bactériens et fongiques de tissus sains et malades, nous avons cherché à mettre en évidence des différences de composition spécifiques et de distribution de ces flores sur 2 campagnes de prélèvements réalisées en 2010 et 2012. Alors que la microscopie électronique à transmission nous a permis de visualiser des structures d'origine virale probable au niveau des chloroplastes du parenchyme chlorophyllien, une étude moléculaire de séquençage de gènes ribosomaux nous a permis de corréler l'apparition de ces structures a de profondes modifications qualitative et quantitative de la microflore endophyte. Ainsi il nous est apparu que la symptomologie de la maladie était corrélée à une modification profonde de la distribution spécifique de la microflore endophyte, visible à la fois au niveau du compartiment fongique et bactérien, suggérant la complète disparition de la pression de sélection exercée par le palmier sain sur sa flore et mise en évidence dans les 2 cas, par un shift d'une répartition de type Poisson vers une répartition normale. Dans le compartiment fongique, une claire déplétion des Pleosporaceae, associées à la plante saine pouvait ainsi être liée à une apparition de nouvelles familles (Trichocomaceae et Mycosphaerellaceae). De même, parmi les bactéries, une disparition des Rhizobium et Ensifer sp associés au compartiment racinaire de la plante saine a ainsi pu être mise en évidence, ces espèces pouvant servir ultérieurement d'indicatrices de bonne santé des palmiers. Dans une deuxième partie de notre travail nous avons cherché à utiliser des éléments de la flore endophyte mais également de substances naturelles dans la lutte biologique contre d'autres pathogènes du palmier. Ainsi, un antagonisme a été mis en évidence entre une souche endophyte d'Arthrobacter agilis et un pathogène majeur, Fusarium oxysporum sp AlbedinisThe Brittle Leaf Disease of the Date Palm Tree (Phoenix dactylifera L.) constitutes a case study of an emerging disease of economic impact caused by a yet uncharacterized etiologic agent. Our strategy was to develop an approach that could be indistinctly transposed to any situation of this type. While basing our investigations on the successive characterization of the diversity of viral, bacterial and fungal endophytic compartments of healthy and diseased Palm trees, we aimed at enlightening differences in species composition but also distribution over two sampling campaigns performed in 2010 and 2012. While transmission electronic microscopy allowed us to visualize structures of probable viral origin affecting chloroplasts of the chlorophyllic cell layer, a molecular approach based on ribosomal gene sequencing allowed us to evidence correlations between the occurrence of such structures and deep modifications of the structure of the palm date tree associated endophytic flora suggesting a strong depletion of the ability of the palm to control its associated endophytes. This was evidenced in both fungal and bacterial compartments by a shift from a Poisson like diversity distribution towards a Gaussian distribution in the flora associated to MFC affected palms. In the fungal compartment, Pleosporaceae, that dominated in healthy palms were replaced by an opportunistic flora of Trichocomaceae and Mycosphaerellaceae. Among bacteria, the disappearance of Rhizobium and Ensifer species, typically associated to the root compartment of healthy palms was enlighten, suggesting that these species could indeed be used as biomarkers of healthy plant status. In a second part of this study, we investigated the potential use of cultivable palm endophytes, but also natural compounds for biocontrol applications. In particular, we evidence the antagonistic potential of Arthrobacter agilis, a palm endophyte, against a major palm date disease agent, Fusarium oxysporum sp. Albedinis
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Mohotti, Keerthi Meepe. "Non-chemical approaches for the management of the root lesion nematode, Pratylenchus loosi Loof, 1960 in tea (Camellia sinensis (L.) O. Kuntze) : with special reference to use of endospore-forming bacterium, Pasteuria penetrans". Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265105.
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Misery, Boris. "Etude des écosystèmes microbiens cidricoles : quel impact sur la qualité organoleptique ? Diversity and dynamics of bacterial and fungal communities in cider for distillation Impact of maturation and contribution of microbial ecosystem on aromatic compounds of cider for distillation and calvados Comparison of microbial dynamics and distillates at laboratory and industrial scales Genetic and metabolic diversity of the degradation of glycerol by Lactobacillus species isolated from ciders Comparative genomics of Lactobacillus collinoides strains isolated from cider reveals different genetic determinants of glycerol degradation". Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC209.
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Le calvados est une eau-de-vie obtenue par distillation du cidre. Le cidre de distillation résulte d’une fermentation naturelle spontanée non maîtrisée, qui permet toutes les interactions possibles entre les différentes communautés microbiennes. En fin de fermentation alcoolique, le glycérol produit peut être dégradé et converti en 3-hydroxypropionaldehyde (3-HPA) par Lactobacillus collinoides via l’enzyme glycérol déshydratase codée par l’opéron pdu. Lors de la distillation, la déshydratation du 3-HPA en acroléine entraîne des désordres organoleptiques connus sous le nom de piqûre acroléique en développant un goût d’amertume dans les calvados. Ces travaux de thèse ont eu pour premier objectif d’apporter une réelle nouveauté dans l’étude de la diversité de dix cidres de distillation normands lors de la fermentation par une approche de métagénomique et d’établir des liens entre la composition microbienne et la qualité aromatique. Cette approche a permis de mettre en évidence plus de 40 genres bactériens et fongiques et des différences significatives ont été constatées au sein de ces populations entre les cidres des différents producteurs au cours du processus de fermentation, suggérant que les pratiques d’élaboration mènent à une typicité du cidre et donc à celle du calvados. L’étude de la composition des communautés microbiennes en lien avec la composition aromatique des cidres de distillation et celle des micro- distillats a été effectuée. Trois groupes de dynamiques et compositions microbiennes, directement liées aux producteurs, émergent conduisant à des compositions aromatiques différentes. L’analyse comparative de huit génomes de souches de Lactobacillus collinoides isolées à partir de cidres de distillation portant sur les métabolismes associés à la fermentation et sur la capacité des souches à métaboliser le glycérol a été effectuée. Deux types d’opéron pdu se profilent et cette variabilité génétique observée entre les souches de L. collinoides suggère des capacités différentes de dégradation du glycérol. Un plan expérimental (D-optimal) faisant varier 6 facteurs (glucose, fructose, azote, éthanol, acide malique, pH) a été élaboré pour étudier le métabolisme du glycérol chez ces souches. Trois profils génétiques et métaboliques ont pu être mis en évidence. Les souches de L. collinoides possédant l’opéron de type I sont toujours capables de dégrader le glycérol, contrairement à celles porteuses de l’opéron de type II. Ces travaux ouvrent des perspectives intéressantes quant à la présence et la physiologie de L. collinoides lors de l’élaboration du cidre et son implication dans la piqûre acroléiqueCalvados is a Normandy brandy made by the distillation of cider. Ciders destined for distillation resultfrom spontaneous fermentation without any human intervention, leading to various interactions between thedifferent microbial communities. At the end of alcoholic fermentation, glycerol produced can be degraded andconverted to 3-hydroxypropionaldehyde (3-HPA) by Lactobacillus collinoides via the glycerol dehydrataseenzyme encoded by the pdu operon. During distillation, dehydration of 3-HPA to acrolein leads to organolepticdisorders, developing a bitterness taste in calvados known as “piqûre acroléique”. The first objective of this thesiswas to unveil the diversity of ten ciders for distillation during fermentation using a high throughput sequencing(16S, ITS1) approach and to establish links between microbial composition and aromatic quality. This approachallowed us to identify more than 40 bacterial and fungal and significant differences were found among fungal andbacterial populations between producers during the fermentation process, suggesting that the practices lead to thetypicity of cider, and therefore to the typicity of calvados. The study of the microbial composition was correlatedwith the aromatic composition of ciders for distillation during the fermentation process and of the micro-distillates.Three groups of microbial dynamics and compositions, directly related to the producers, were observed leading todifferent aromatic compositions. A comparative analysis of eight genomes of Lactobacillus collinoides strainsisolated from the ciders according to the different metabolisms associated with fermentation as well as on theability of the strains to metabolize glycerol was performed. Two types of operon pdu were highlighted and thisgenetic variability between L. collinoides strains suggests different abilities for glycerol degradation. Anexperimental design (D-optimal) by varying 6 factors (glucose, fructose, nitrogen, ethanol, malic acid, pH) wasdeveloped to study the metabolism of glycerol in these strains. 3 genetic and metabolic profiles were identified. L.collinoides strains with operon type I are always able to degrade glycerol, contrarily to those harbouring the operonof type II. This work opens up interesting perspectives regarding the presence and physiology of L. collinoidesduring the development of cider and its involvement in the “piqûre acroléique”
Libros sobre el tema "L-form bacteria"
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AIDS, cancer, and the medical establishment. New York, N.Y: Robert Speller Publishers, 1986.
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Cell wall deficient forms: Stealth pathogens. 3a ed. Boca Raton, Fla: CRC Press, 2001.
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Cell wall deficient forms: Stealth pathogens. 2a ed. Boca Raton, Fla: CRC Press, 1993.
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1915-, Crane John, ed. The cancer cure that worked: Fifty years of suppression. Toronto, Canada: Marcus Books, 1987.
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Lynes, Barry. The cancer cure that worked!: Fifty years of suppression. Toronto, Canada: Marcus Books, 1987.
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Sarabelle, Madoff, ed. The Bacterial L-forms. New York: Marcel Dekker, 1986.
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Mattman, Lida H. Cell Wall Deficient Forms: Stealth Pathogens, Third Edition. 3a ed. CRC, 2000.
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Mattman, Lida H. Cell Wall Deficient Forms: Stealth Pathogens. Taylor & Francis Group, 2000.
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Mattman, Lida H. Cell Wall Deficient Forms: Stealth Pathogens. Taylor & Francis Group, 2009.
Buscar texto completoCapítulos de libros sobre el tema "L-form bacteria"
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Moosmayer, Dieter y Jörg F. Rippmann. "Expression of scFv in L-Form Bacteria". En Antibody Engineering, 266–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-04605-0_19.
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Paton, A. M. "L-Form Bacteria and Somatic Associations with Eucaryotes". En Safety Assurance for Environmental Introductions of Genetically-Engineered Organisms, 199–202. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73169-3_11.
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Allan, E. J., C. M. Innes y A. M. Paton. "Modification of Plants Using Intracellular Associations of L-Form Bacteria". En Progress in Plant Protoplast Research, 349–50. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2788-9_125.
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Madoff, Sarabelle y John W. Lawson. "The L-Forms of Bacteria". En The Prokaryotes, 4068–81. New York, NY: Springer New York, 1992. http://dx.doi.org/10.1007/978-1-4757-2191-1_68.
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Vollmer, R., J. Espirilla, J. C. Sánchez, L. Arroyo, G. Flores, A. Rojas, N. L. Anglin, J. Kreuze y D. Ellis. "Accelerated In Vitro Propagation of Sweetpotato Clones (Ipomoea batatas L.)". En Technologies in Plant Biotechnology and Breeding of Field Crops, 133–49. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-5767-2_7.
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AbstractFast and reliable propagation of plant material is an important need in different stages of breeding programs and production systems. In vitro propagation ensures that pathogen- and virus-free plants stay phytosanitary clean over time while providing high multiplication rates. Using liquid instead of solid culture medium can reduce the interval of individual propagation cycles and contributes to speeding up of the process (1.5–2.5 times), especially during the initial growth phase of the plants. Sophisticated immersion systems have been developed for many plant species, but they are difficult to apply when hundreds or thousands of different genotypes are propagated simultaneously. Additionally, these systems require a high input of technical equipment, know-how and experience to avoid bacterial or fungal contamination during the propagation process. The following protocol describes a low-input suspension technique that combines the use of liquid and solid medium, and permits the successful propagation of genetically diverse sweetpotato genotypes [Ipomoea batatas (L.) Lam.] with a high multiplication rate. As sweetpotato is an important staple crop in low-income/technology countries of Africa, Asia, and South America, the described method may find valuable application for the breeding programs in these regions.
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Sofkova-Bobcheva, Svetla, Ivelin Pantchev, Ivan Kiryakov, Petar Chavdarov, Yordan Muhovski, Fatma Sarsu y Nasya Tomlekova. "Induced mutagenesis for improvement of bean (Phaseolus vulgaris L.) production in Bulgaria." En Mutation breeding, genetic diversity and crop adaptation to climate change, 178–93. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0018.
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Abstract Although historically a surplus food producer, Bulgarian agriculture has faced a downturn in recent decades. Local legume cultivars have lost favour with farmers and the canning industry, due to their low productivity in comparison with imported ones. Diseases and abiotic stresses are the most important factors limiting the production of edible legumes, costing farmers hundreds of euros in lost revenue each year. The overall objective of our ongoing bean mutation breeding programme was to enrich the gene pool of Phaseolus vulgaris L. and to develop genotypes resistant to Xanthomonas axonopodis pv. phaseoli (Smith) (Xap) and Pseudomonas savastanoi pv. phaseolicola (Burkh.) (Psp) using EMS. An elite line and common cultivar (an heirloom and a snap bean type) in Bulgaria, were selected as parents and the chemical mutagen EMS was used for generating mutations. In total, 1000 seeds were treated and the two generated M1 populations were grown in the field. All M2 mutant plants (1650 from initial line IP564 and 2420 from initial cultivar 'Mastilen 11b') were grown in field conditions and a number of phenotypic changes were observed on these mutated plants. They were also screened for Xap disease resistance via leaf artificial inoculation under greenhouse conditions. Individual plant selection was performed for the putatively resistant M2 plants. In the M3 generation these lines were screened using artificial inoculation with Xap and Psp pathogens (leaves and pods) under field conditions. Selected M3-M4 lines with confirmed disease resistance were tested for fresh pod quality. Yield tests were started in M4 and M5 generations and, according to their productivity performance, mutants were advanced to the M6/M7 generation for validation. The expression patterns of genes putatively involved in the resistance reactions towards two races of Psp were determined using qRT-PCR for the specific and reference genes. In conclusion, 50 plants with visible morphological changes and/or increased tolerance to the two targeted bacterial diseases were selected. A total of 20 advanced mutant bean lines are currently being evaluated for their competitiveness in multiple sites.
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Aoki, Takavhiko. "Behaviour of a Sialo-Oligosaccharide from Glycophorin in Teleost Red Blood Cell Membranes". En Animal Models and Experimental Research in Medicine [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107234.
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Glycophorins (GPs) in red blood cell (RBC) membranes of carp (Cyprinus carpio L.) exhibit bacteriostatic activity against various gram-negative and gram-positive bacteria including fish pathogens. This physiological property also exists in the GPs of yellow tail (Seriola quinqueradiata) and red sea bream (Pagrus major). Thus, we concluded that this antimicrobial activity is not confined to these teleost species but can be found in all fish. This bacteriostatic activity is caused by the sialo-oligosaccharide from these teleost GPs. Only the N-glycolylneuraminic acid (NeuGc) form of sialic acid was detected in the carp. Using NMR and GC–MS, we determined that the structure of the bacteriostatic sialo-oligosaccharide from carp was NeuGcα2→6 (Fucα1→4) (Glcα1→3) Galβ1→4GalNAc-ol. The bacteriostatic activity of this monosialyl-oligosaccharide is due to the property of the lectin receptor. It is supposed that some lectin-like proteins exist on the surface of gram-positive bacteria or the flagellum of gram-negative bacteria. Based on the electron microscope observations, teleost GPs containing the sialo-oligosaccharide are released from RBC membranes and then adsorbed onto the surface or the flagellum of invading bacteria in the blood.
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Allan, E. J., C. Hoischen y J. Gumpert. "Chapter 1 Bacterial L‐Forms". En Advances in Applied Microbiology, 1–39. Elsevier, 2009. http://dx.doi.org/10.1016/s0065-2164(09)01201-5.
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Satchanska, Galina. "Growing Environmental Bacterium Biofilms in PEO Cryogels for Environmental Biotechnology Application". En Bacterial Biofilms [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.104813.
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This Chapter discusses the entrapment, growing and biofilm formation by an environmental bacterium immobilized in polyethyleneoxide cryogel to be applied in environmental biotechnology. The KCM-R5 bacterium was isolated from the heavy metal-polluted environment near a large Pb-Zn smelter, also producing precious metals in Bulgaria. Molecular-genetic analysis revealed affiliation with Pseudomonas rhodesiae. The strain is capable of growing in high concentrations of phenol and different phenol derivatives. Polyethylene oxide was found to be friendly and nontoxic to bacteria polymer enabling bacteria easy to penetrate in it and fast to grow. KCM-R5 biofilms were grown for 30 days in batch culture with phenol (300-1000 mg L−1) dissolved in the mineral medium. The bacterium was able to involve phenol in its metabolism and use it as a single carbon supplier. The results obtained in the study showed 98% phenol biodegradation using the biotech installation described. The proposed PEO cryogel-P. rhodesiae KCM-R5 bacterium biotech biofilter can be used for environmental biotechnology application in industrial wastewater detoxification.
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E. Khrulev, Alexey, Irina V. Belova, Irina V. Soloveva, Anna G. Tochilina, Natalya A. Shiyanova, Anastasiya A. Nikitina y Natalya S. Khruleva. "Specific Cerebrovascular Risk Factors, Colon Microbiocenosis and Its Correction in Patients Receiving Long-Term Programmed Hemodialysis". En Multidisciplinary Experiences in Renal Replacement Therapy. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101300.
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Introduction: The problem of acute and chronic cerebrovascular disorders in dialysis patients remains the most urgent. Risk factors for cerebrovascular diseases in CKD and dialysis patients can be conditionally divided into “traditional” (arterial hypertension, diabetes mellitus, hypercholesterolemia) and “specific” (associated with renal pathology and dialysis procedures). The spectrum of specific factors of cerebrovascular risk in patients with dialysis stage of the CKD includes specific dialysis factors that form during programmed HD, as well as impaired phosphorus-calcium metabolism and calcification of the arterial microvasculature, increased blood levels of β2-microglobulin, homocysteine, malondialdehyde and superoxide dismutase, a decrease in the level of nitric oxide (II) metabolites, development of nephrogenic anemia and dysfunction of blood cells, malnutrition and dietary features of patients with renal pathology, accumulation of uremic toxins and toxins of intestinal bacteria, etc. Opportunistic gut microorganisms can produce uremic toxins, which are associated with an increased risk of inflammation, increased oxidative stress, and a higher risk of cardiovascular disease (CVD). Description of the spectrum of risk factors for cerebrovascular pathology in dialysis patients and effective control over them seems to be an effective strategy aimed at increasing the duration and quality of life in patients receiving renal replacement therapy. The aim of the investigation was to study the species composition of colon microbiocenosis in patients with CKD receiving programmed HD treatment and to evaluate the effectiveness of its correction using a new immobilized synbiotic. Materials and methods: Samples of colon microbiota from 62 patients undergoing programmed hemodialysis were studied before and after a course of diet therapy that included probiotic components, in particular, the immobilized synbiotic LB-complex L. Isolation of microorganisms was carried out according to our original method; for bacteria identification, a MALDI-TOF Autoflex speed mass spectrometer (Bruker Daltonik, Germany) was used in the Biotyper program mode. The results were assessed using the criteria proposed by the authors and based on the OST 91500.11.0004-2003. The efficacy of the immobilized synbiotic was determined based on the clinical data, questionnaires, and bacteriological tests. Results: In patients receiving programmed hemodialysis (before the start of the diet therapy), chronic moderate inflammation and azotemia were found. Dysbiotic changes in microbiocenosis were revealed in all the examined patients; in the absence or suppression of lacto- and bifidoflora, the number and diversity of Bacteroides spp., Clostridium spp., Collinsella spp., Eggerthella spp. and other bacteria increased, which was consistent with the theory of functional redundancy of gut microbiota. From the answers to the questionnaires, a decrease in the quality of life was found (up to 70 points out of 100) according to six of the eight scales used. After the combined therapy using the synbiotic LB-complex L in the study group, 56% of the examined patients showed their microbiocenosis restored to normal; no grade III dysbiosis was detected in any patient. There was a significant decrease in CRP and ESR in these patients and an improvement in the quality of life by criteria reflecting physical health. Conclusion: Acute/chronic CVD in patients with CKD of the pre-dialysis and dialysis periods are the most frequent and formidable complications. The spectrum of “traditional” and “specific” CV risk factors in dialysis patients will be described in the chapter. Special attention will be paid to the intestinal microbiota and opportunistic intestinal microorganisms. The aim was to study the species composition of colon microbiocenosis in HD patients, and to evaluate the effectiveness of its correction using a new immobilized synbiotic. Materials and Methods. Samples of colon microbiota from 62 HD patients were studied before/after a course of diet therapy that included probiotic components, the immobilized synbiotic LB-complex L. MALDI-TOF Autoflex speed mass spectrometer was used in the Biotyper program mode. The efficacy of the immobilized synbiotic was determined based on the clinical data, questionnaires, and bacteriological tests. Results. Dysbiotic changes in microbiocenosis were revealed in all patients; in the absence/suppression of lacto-and bifidoflora, the number and diversity of Bacteroides spp.,Clostridium spp.,Collinsella spp.,Eggerthella spp. and other bacteria increased. After the combined therapy using the synbiotic LB-complex L in the study group, 56% of the examined patients showed their microbiocenosis restored to normal; no grade III dysbiosis was detected in any patient.
Actas de conferencias sobre el tema "L-form bacteria"
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Breica Borozan, Aurica, Despina-Maria Bordean, Gabriel Bujanca, Delia Dumbrava y Sorina Popescu. "CONTROL OF PLANTS OF LOTUS CORNICULATUS L. ON AEROBIC AND ANAEROBIC FREE NITROGEN-FIXING BACTERIA". En GEOLINKS International Conference. SAIMA Consult Ltd, 2020. http://dx.doi.org/10.32008/geolinks2020/b1/v2/07.
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The free nitrogen fixing bacteria are able to mobilize important soil nutrients, transforming through biological processes the unusable molecular nitrogen into an active form and to improve soil fertility, influence many aspects of plant health and ensure their growth, showing interest for the scientific world and farmers. But, on the other hand, this bacterial segment may be influenced by the edaphic factors and the interconnection with the plants, the growth phase, the physiological state and the root system of the plant, by the root exudates, which demonstrates the importance of the bacterial community monitoring from the area of plants influence throughout the growing periods The aim of this study was to evaluate the influence of the age of the plants used as biofertilizer and soil moisture on the free nitrogen fixing bacterial communities (the genera Azotobacter and Clostridium) associated with the roots of the perennial plants of Lotus corniculatus L. There were two zones of interest, namely the area of influence of the roots of the plants (rhizosphere) but also the more distant area (edaphosphere). For the study of aerobic and anaerobic free nitrogen fixing bacteria soil samples were taken together with adjacent plants of Lotus corniculatus L. The experimental variants were located in the western part of Romania, the plants being cultivated on the same soil type, but on different plots, that were in the I-IV years of culture. The influence of Lotus corniculatus L. plants on the free nitrogen fixing bacteria has been reported in control experimental variants. Isolation and study of this bacterial group from the 8 experimental variants was performed on a specific mineral medium, favorable for the growth of the two bacterial genera. The results were evaluated after 5 and 10 days of incubation. Between the two assesments there were no noticeable differences in the nitrogen fixing bacterial community, except for the stimulatory effect observed in the control vatiant and rhizosphere of the first year culture. The plants influence on aerobic and anaerobic free nitrogen fixing bacteria was obvious in the II and IV years of the Lotus corniculatus L. culture, compared to the 76 control variants and varies substantially depending on the age of the plant. In most analyzed soil samples, both bacterial genera, Azotobacter and Clostridium were present, confirming the known ecological relation of unilateral advantage or passive stimulation of the aerobic bacteria compared to the anaerobic clostridia. Exceptions were the samples from the cultures of the first year (rhizosphere and control), but also the rhizosphere from the culture of the year II, where only anaerobic nitrogen fixing bacteria were detected. Our results suggested that plant-soil interactions exert control over the bacteria being studied.
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Katola, Viktor. "DORMANT BACTERIA (L-FORM) IN THE BLOOD OF SEPARATE GROUPS OF HEALTHY RESIDENTS OF THE AMUR REGION". En XIV International Scientific Conference "System Analysis in Medicine". Far Eastern Scientific Center of Physiology and Pathology of Respiration, 2020. http://dx.doi.org/10.12737/conferencearticle_5fe01d9d82deb1.03874353.
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In the blood of some residents of the Amur Region, structures similar to dormant elementary bodies of L-form bacteria were revealed. It is assumed that they are an indicator of persistent infection in the host. Therefore, it is necessary to expand the methods for studying donor blood and the blood of candidates for donors.
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Terzić, Jelena, Marina Stanković y Olgica Stefanović. "ANTIBIOFILM ACTIVITY OF SELECTED PLANT SPECIES". En 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.280t.
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Bacterial biofilm is a complex community of bacterial cells enclosed in a polymer matrix and attached to a biotic or abiotic substrate. In this living form the bacteria are more resistant to antimicrobial agents than in the form of planktonic cells. Biofilm is a common cause of chronic infections in humans, so due to the growing resistance to antibiotics, alternative methods for controlling infections using medicinal plants have been proposed. In this study, the antibiofilm activity of ethanol and acetone extracts of plants Lamium album, Achillea millefolium and Agrimonia eupatoria against eight clinical isolates of human pathogenic bacteria was examined. Inhibition of biofilm formation was demonstrated using the crystal violet test and the effect on metabolic activity was confirmed by the use of resazurin dye test. Ethanol extract of L. album showed the greatest activity against P. aeruginosa (PA9) at a concentration of 20 mg/ml (> 80% of inhibition), while acetone extract acted at a concentration of 5 mg/ml (≥ 18%) against Klebsiella sp. (K9). At a concentration of 10 mg/ml, the ethanol extract of A. millefolium was effective against E. coli (E16) and P. aeruginosa (PA8) (> 70%), while the acetone extract was effective at 2.5 mg/ml (> 80%) against E. coli (E16). Ethanol and acetone extracts of A. eupatoria were effective at a concentration of 10 mg/ml (> 50%) against E. coli (E16). The antibiofilm activity of the tested plant extracts on certain clinical isolates indicates their great potential in the treatment of infections caused by biofilm-producing bacteria.
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Baranskaya, M. I., L. A. Chaikovskaya y N. N. Klimenko. "Primary evaluation of a new strain of phosphate-mobilizing bacteria". En CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-2020-5-9-10-104.
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An initial assessment of new strains of phosphate-mobilizing bacteria isolated from the rhizosphere of cereals was carried out in the laboratory. According to the results of the quantitative evaluation of the phosphate solubilizing activity of bacteria, we found that 12 strains have the greatest ability to transform Ca3(PO4)2 into a soluble form. The highest Кr value was noted for strain 0613: the coefficient of phosphate solubilizing activity – 10. The maximum content of soluble (212 mg/l P2O5) phosphorus was in the culture liquid of strain 1702.
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Sarsam, Saad y Mohammed Sulaiman. "Reservation and Development of Rigid Pavement Quality with the Aid of Bacteria". En INTERNATIONAL CONFERENCE ON ARCHITECTURAL AND CIVIL ENGINEERING 2020. Cihan University-Erbil, 2021. http://dx.doi.org/10.24086/aces2020/paper.205.
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Initiation of Microcracks in rigid pavement usually starts within few hours of casting due to the shrinkage of concrete and casting at hot environment condition. Cracking proceeds and changes to macrocracks throughout the service life of the pavement due to repetitions of compressive, tensile, and shear stress under wheel loading. Such cracking exhibits a durability problem since the ingress of moisture and harmful chemicals such as sulphates and chlorides into the concrete through the cracks can cause premature matrix degradation and corrosion of embedded steel reinforcement at joints, which may result in the decrement of strength and service life. In this work, implementation of self-healing techniques was adopted with the aid of bacteria and healing agent to precipitate CaCo3 on the formed micro-cracks. The precipitation of calcite by continuous hydration of cement helps in production of calcium carbonate precipitation with the help of bacteria. A soil bacterium named Bacillus subtilis was cultured in the laboratory, the concentration of bacteria cell of B. subtilits in normal saline (NaCl, 9 g/l) suspension was 106 cell/ml. Concrete specimens of various type (cube of 100x100x100 mm, cylinder of 100mm diameter and 200mm height, and beam of 100 x 100 x 500 mm) size have been prepared in the laboratory, then separated to three sets. The first set of specimens were subjected to controlled compression and flexure pre-cracking, then subjected to healing and curing in a water bath which contains the prementioned bacteria at 20°C for 7 days. The second set was the control specimens cured in water bath for 7 and 28 days at 20°C. The third set of specimens were subjected to healing and curing in a water bath which contains the prementioned bacteria at 20°C for 7 and 28 days and then tested for compressive, indirect tensile, and flexure properties. It was observed that the healing process provided by the bacteria have improved the overall properties of concrete by (23, 11 and 16) % for compressive, tensile and flexure strength respectively as compared to those of control mixture after 28 days of curing. On the other hand, specimens subjected to controlled pre-cracking exhibit improvement in strength properties after the healing process provided by the bacteria by (28 and 33) % for compressive and flexure strength respectively as compared to those of control mixture after 7 days of curing. It was concluded that spraying of bacterial water for curing the concrete is beneficial and can be considered as sustainable and environment friendly solution for maintenance. Bacteria can reserve, develop and maintain the quality of rigid pavement.
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Kameneva, I. A., A. I. Yakubovskaya, V. S. Pashtetskiy, N. Yu Polyakova, M. V. Gritchin, I. I. Smirnova y G. N. Konopleva. "Prospect of using oilcakes in biotechnology of microbial preparations". En CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution "Research Institute of Agriculture of Crimea", 2020. http://dx.doi.org/10.33952/2542-0720-2020-5-9-10-112.
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The actual problem in the development of new and improvement of existing forms of microbial preparations for crop production is the search for technological and economical components of the substrate to increase the titer of bacteria and keep their viability for a long period. The aim of our research was to study the technological effectiveness of the oilcake obtained after oil extraction from seeds of Linum usitatissimum L. (flax) and Brassica spp. L. (mustard) as a component of a liquid nutrient medium for the cultivation of associative bacteria. The addition of mustard and flax cake to the cultivation medium of P. polymyxa CCM P contributed to an increase in the titer of bacteria by 3.1 and 4.3 times, respectively, compared to control. We found that mustard cake has a stimulating and stabilizing effect on P. polymyxa CCM P, as well as a stabilizing one on L. nimipressuralis 32-3 CCM when storing for a month.
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Didovich, S. V., O. P. Alekseenko y A. N. Pas'. "Symbiotic efficiency of nodule bacteria strains on legumes". En РАЦИОНАЛЬНОЕ ИСПОЛЬЗОВАНИЕ ПРИРОДНЫХ РЕСУРСОВ В АГРОЦЕНОЗАХ. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-15.05.2020.08.
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Nowadays, ecologization is one of the important tasks for agriculture. Microbiological preparations based on nodule bacteria application in agriculture is a significant part of organic crop production. Symbiotic efficiency of 13 nodule bacteria strains from the Crimean collection of microorganisms of the FSBSI “Research Institute of Agriculture of Crimea” (http://www.ckp- rf.ru/usu/507484/) was studied in our research. In laboratory conditions, we established that four strains of Rhizobium leguminosarum bv. viceae and five strains of Bradуrhizobium japonicum have high symbiotic efficiency to Pisum sativum L., Lathyrus sativus L., Glycinе max L.(Merr.). These strains are recommended for identifying highly effective ones to modern cultivars of these legumes in the conditions of the steppe zone of Crimea.
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Hanifah, Mohd Azri, Sai Ravindra Panuganti, Nur Atiqah Zakaria, Nur Hazrina Kamarul Zaman y Raj Deo Tewari. "Reservoir Souring Prediction in Deepwater Reservoirs for Field Development Planning". En SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205791-ms.
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Abstract A deep-water Field X with two major Reservoirs U and L discovered recently offshore Malaysia is on development for early production. The subsurface plan for the Field X includes water injection. But the presence of sulphate rich seawater can provide a favorable environment for souring activity to take place. This study evaluates the reservoir souring potential for the green Field X as a result of seawater flooding. Reservoir souring is the increase of the hydrogen sulfide (H2S) concentration in produced reservoir fluids. As hydrogen sulfide is a highly toxic and corrosive gas, the production of H2S has a huge impact on the safety, infrastructure and facilities of the field. Whether a reservoir is susceptible to souring is dependent on a variety of factors. Some of these include water injection flow rate, temperature of the reservoir, presence of bacterial nutrients and rock minerology. Effective prediction of biogenic reservoir souring using computer models is essential when undertaking major technical and economic decisions regarding field development. For H2S concentration calculation PETRONAS utilized in-house stand-alone modeling tool that considers physicochemical hydrodynamics of multiphase flow, heat transfer, substrate propagation and bacterial activity. The simulator looks at bacterial growth both in planktonic and sessile forms. Monod kinetics is applied for the growth of bacteria, leading to the consumption of sulphate and volatile fatty acids which in-turn is linked to H2S generation. Along with H2S propagation, H2S scavenging by rock and H2S partitioning between the various phases is also accounted for. The model can also deal with the effects of lift gas, reinjection of sour produced water, injection of biocide and nitrite. Since the Field X is a green field and historical production data is unavailable, the model is calibrated against the provided field development plan (FDP) data with sensitivity analysis. The simulation runs show that the H2S breakthrough occurs before the end of production. The amount of H2S produced indicates that the risk of reservoir souring associated with seawater injection in U and L Reservoirs of the Field X is high. It is recommended to evaluate different reservoir souring preventive measures in combination with mitigative options in terms of chance of success, risks, and cost (CAPEX/OPEX) in the context of the Field X development plan.
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Duran, Nizami. "New Approaches to the Treatment of Drug-Resistant Bacteria". En The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.iii.10.
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Today, the treatment of infectious diseases is getting more difficult every day due to increasing drug resistance against microorganisms. In order to overcome the increasing drug resistance globally, a wide variety of studies are carried out on probiotic microorganisms. In this study, we aimed to investigate the synergistic activities of the bioactive components of L. casei and S. thermophilus probiotic microorganisms against ESBL-positive E. coli and K. pneumoniae strains against these two microorganisms. The non-toxic concentrations of L. casei and S. thermophilus bioactive components in Vero cell culture were determined. Antibacterial activities against ESBL-positive E. coli and K. pneumoniae at determined non-toxic concentrations were evaluated by studying MIC and MBC concentrations. Firstly, non-cytotoxic concentrations of bioactive metabolites of S. thermophilus and L. casei were determined on Vero cells. It has been determined that the bioactive metabolites of both S. thermophilus and L. casei cause toxicity of <32 µg/ml. For this reason, studies have been studied at levels lower than this concentration for antimicrobial efficacy studies. Antimicrobial activities of L. casei and S. thermophilus alone and in combination against E. coli were given. Here, it was determined that the activities of probiotic microorganisms created a synergistic effect when used in combination. It was determined that the activities of L. casei and S. thermophilus, when used in combination, had a synergistic effect against K. pneumoniae. In this study, where we aimed to produce a new and effective drug/solution in the treatment of wounds infected with drug-resistant bacteria (E. coli and K. pneumoniae), which are very difficult to treat, our findings may be hopeful.
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Ananyeva, I. N., Z. M. Aleschenkova, P. V. Rybaltovskaya y M. A. Chindareva. "Effect of soybean (Glycine max (L.) Merill) treatments on the introduction capacity of endophytic bacteria". En CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-2020-5-9-10-103.
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The goal of the work was to obtain antibiotic-resistant forms of endophytic Glycine max L. (Merill) bacteria and to study their introduction potential affected by different seed treatment methods. Rifampicin-resistant variants of endophytic soybean bacteria Rhizobium radiobacter 27c and Pseudomonas fluorescens 11E preserving valuable properties were derived. Soybean seed treatment with Bradyrhizobium japonicum BIM V-501D and endophytic nitrogen-fixing Rh. radiobacter 27c, phosphate-mobilizing Ps. fluorescens 11E bacteria under model conditions promoted accumulation of nitrogen-fixing bacteria in the root, stem and leaves. The number of nodules rose by 70% compared with the mono-inoculated control; plant height increased by 19%.
Informes sobre el tema "L-form bacteria"
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Evans, Donald L., Avigdor Eldar, Liliana Jaso-Friedmann y Herve Bercovier. Streptococcus Iniae Infection in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Towards the Pathogen and Vaccine Formulation. United States Department of Agriculture, febrero de 2005. http://dx.doi.org/10.32747/2005.7586538.bard.
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The objectives of the BARD proposal were to determine the mechanisms of nonspecific cytotoxic cells (NCC) that are necessary to provide heightened innate resistance to infection and to identify the antigenic determinants in Streptococcus iniae that are best suited for vaccine development. Our central hypothesis was that anti-bacterial immunity in trout and tilapia can only be acquired by combining "innate" NCC responses with antibody responses to polysaccharide antigens. These Objectives were accomplished by experiments delineated by the following Specific Aims: Specific aim (SA) #1 (USA) "Clone and Identify the Apoptosis Regulatory Genes in NCC"; Specific aim #2 (USA)"Identify Regulatory Factors that Control NCC Responses to S. iniae"; Specific aim #3 (Israel) "Characterize the Biological Properties of the S. iniae Capsular Polysaccharide"; and Specific aim #4 (Israel) "Development of an Acellular Vaccine". Our model of S. iniae pathogenesis encompassed two approaches, identify apoptosis regulatory genes and proteins in tilapia that affected NCC activities (USA group) and determine the participation of S.iniae capsular polysaccharides as potential immunogens for the development of an acellular vaccine (Israel group). We previously established that it was possible to immunize tilapia and trout against experimental S. difficile/iniaeinfections. However these studies indicated that antibody responses in protected fish were short lived (3-4 months). Thus available vaccines were useful for short-term protection only. To address the issues of regulation of pathogenesis and immunogens of S. iniae, we have emphasized the role of the innate immune response regarding activation of NCC and mechanisms of invasiveness. Considerable progress was made toward accomplishing SA #1. We have cloned the cDNA of the following tilapia genes: cellular apoptosis susceptibility (CAS/AF547173»; tumor necrosis factor alpha (TNF / A Y 428948); and nascent polypeptide-associated complex alpha polypeptide (NACA/ A Y168640). Similar attempts were made to sequence the tilapia FasLgene/cDNA, however these experiments were not successful. Aim #2 was to "Identify Regulatory Factors that Control NCC Responses to S. iniae." To accomplish this, a new membrane receptor has been identified that may control innate responses (including apoptosis) of NCC to S. iniae. The receptor is a membrane protein on teleost NCC. This protein (NCC cationic antimicrobial protein-1/ncamp-1/AAQ99138) has been sequenced and the cDNA cloned (A Y324398). In recombinant form, ncamp-l kills S. iniae in vitro. Specific aim 3 ("Characterize the Biological Properties of the S.iniae Capsular Polysaccharide") utilized an in- vitro model using rainbow trout primary skin epithelial cell mono layers. These experiments demonstrated colonization into epithelial cells followed by a rapid decline of viable intracellular bacteria and translocation out of the cell. This pathogenesis model suggested that the bacterium escapes the endosome and translocates through the rainbow trout skin barrier to further invade and infect the host. Specific aim #4 ("Development of an Acellular Vaccine") was not specifically addressed. These studies demonstrated that several different apoptotic regulatory genes/proteins are expressed by tilapia NCC. These are the first studies demonstrating that such factors exist in tilapia. Because tilapia NCC bind to and are activated by S. iniae bacterial DNA, we predict that the apoptotic regulatory activity of S. iniae previously demonstrated by our group may be associated with innate antibacterial responses in tilapia.
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova y Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, enero de 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.
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Kapulnik, Yoram y Donald A. Phillips. Isoflavonoid Regulation of Root Bacteria. United States Department of Agriculture, enero de 1996. http://dx.doi.org/10.32747/1996.7570561.bard.
Texto completoResumen
The overall objective of this project was to develop a conceptual framework for enhancing root colonization by beneficial bacteria. To accomplish this aim we tested the hypothesis that production and excretion of the plant phytoalexin medicarpin can be used for creation of a special niche along the legume roots, where beneficial microorganism, such as rhizobium, will have a selective advantage. On the Israeli side it was shown that higher medicarpin levels are exuded following the application of Rhizobium meliloti to the rhizosphere but the specific biochemical pathway governing medicarpin production was not induced significantly enough to support a constant production and excretion of this molecule to the rhizosphere. Furthermore, pathogenic bacteria and chemical elicitors were found to induce higher levels of this phytoalexin and it became important to test its natural abundance in field grown plants. On the US side, the occurrence of flavonoids and nucleosides in agricultural soils has been evaluated and biologically significant quantities of these molecules were identified. A more virulent Agrobacterium tumefaciens strain was isolated from alfalfa (Medicago sativa L.) which forms tumors on a wide range of plant species. This isolate contains genes that increase competitive colonization abilities on roots by reducing the accumulation of alfalfa isoflavonoids in the bacterial cells. Following gene tagging efforts the US lab found that mutation in the bacterial efflux pump operons of this isolate reduced its competitive abilities. This results support our original hypothesis that detoxification activity of isoflavenoids molecules, based on bacterial gene(s), is an important selection mechanism in the rhizosphere. In addition, we focused on biotin as a regulatory element in the rhizosphere to support growth of some rhizosphere microorganisms and designed a bacterial gene construct carrying the biotin-binding protein, streptavidin. Expressing this gene in tobacco roots did not affect the biotin level but its expression in alfalfa was lethal. In conclusion, the collaborative combination of basic and applied approaches toward the understanding of rhizosphere activity yielded new knowledge related to the colonization of roots by beneficial microorganisms in the presence of biological active molecules exuded from the plant roots.
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Hutchinson, M. L., J. E. L. Corry y R. H. Madden. A review of the impact of food processing on antimicrobial-resistant bacteria in secondary processed meats and meat products. Food Standards Agency, octubre de 2020. http://dx.doi.org/10.46756/sci.fsa.bxn990.
Texto completoResumen
For meat and meat products, secondary processes are those that relate to the downstream of the primary chilling of carcasses. Secondary processes include maturation chilling, deboning, portioning, mincing and other operations such as thermal processing (cooking) that create fresh meat, meat preparations and ready-to-eat meat products. This review systematically identified and summarised information relating to antimicrobial resistance (AMR) during the manufacture of secondary processed meatand meat products (SPMMP). Systematic searching of eight literature databases was undertaken and the resultantpapers were appraised for relevance to AMR and SPMMP. Consideration was made that the appraisal scores, undertaken by different reviewers, were consistent. Appraisal reduced the 11,000 initially identified documents to 74, which indicated that literature relating to AMR and SPMMP was not plentiful. A wide range of laboratory methods and breakpoint values (i.e. the concentration of antimicrobial used to assess sensitivity, tolerance or resistance) were used for the isolation of AMR bacteria.The identified papers provided evidence that AMR bacteria could be routinely isolated from SPMMP. There was no evidence that either confirmed or refuted that genetic materials capable of increasing AMR in non-AMR bacteria were present unprotected (i.e. outside of a cell or a capsid) in SPMMP. Statistical analyses were not straightforward because different authors used different laboratory methodologies.However, analyses using antibiotic organised into broadly-related groups indicated that Enterobacteriaceaeresistant to third generation cephalosporins might be an area of upcoming concern in SPMMP. The effective treatment of patients infected with Enterobacteriaceaeresistant to cephalosporins are a known clinical issue. No AMR associations with geography were observed and most of the publications identified tended to be from Europe and the far east.AMR Listeria monocytogenes and lactic acid bacteria could be tolerant to cleaning and disinfection in secondary processing environments. The basis of the tolerance could be genetic (e.g. efflux pumps) or environmental (e.g. biofilm growth). Persistent, plant resident, AMR L. monocytogenes were shown by one study to be the source of final product contamination. 4 AMR genes can be present in bacterial cultures used for the manufacture of fermented SPMMP. Furthermore, there was broad evidence that AMR loci could be transferred during meat fermentation, with refrigeration temperatures curtailing transfer rates. Given the potential for AMR transfer, it may be prudent to advise food business operators (FBOs) to use fermentation starter cultures that are AMR-free or not contained within easily mobilisable genetic elements. Thermal processing was seen to be the only secondary processing stage that served as a critical control point for numbers of AMR bacteria. There were significant linkages between some AMR genes in Salmonella. Quaternary ammonium compound (QAC) resistance genes were associated with copper, tetracycline and sulphonamide resistance by virtue of co-location on the same plasmid. No evidence was found that either supported or refuted that there was any association between AMR genes and genes that encoded an altered stress response or enhanced the survival of AMR bacteria exposed to harmful environmental conditions.
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Weinberg, Zwi G., Richard E. Muck, Nathan Gollop, Gilad Ashbell, Paul J. Weimer y Limin Kung, Jr. effect of lactic acid bacteria silage inoculants on the ruminal ecosystem, fiber digestibility and animal performance. United States Department of Agriculture, septiembre de 2003. http://dx.doi.org/10.32747/2003.7587222.bard.
Texto completoResumen
The overall objective of the whole research was to elucidate the mechanisms by which LAB silage inoculants enhance ruminant performance. The results generated will permit the development of better silage inoculants that maximize both silage preservation and animal performance. For this one-year BARD feasibility study, the objectives were to: 1. determine whether lactic acid bacteria (LAB) used in inoculants for silage can survive in rumen fluid (RF) 2.select the inoculants that survived best, and 3. test whether LAB silage inoculants produce bacteriocins-like substances. The most promising strains will be used in the next steps of the research. Silage inoculants containing LAB are used in order to improve forage preservation efficiency. In addition, silage inoculants enhance animal performance in many cases. This includes improvements in feed intake, liveweight gain and milk production in 25-40% of studies reviewed. The cause for the improvement in animal performance is not clear but appears to be other than direct effect of LAB inoculants on silage fermentation. Results from various studies suggest a possible probiotic effect. Our hypothesis is that specific LAB strains interact with rumen microorganisms which results in enhanced rumen functionality and animal performance. The first step of the research is to determine whether LAB of silage inoculants survive in RF. Silage inoculants (12 in the U.S. and 10 in Israel) were added to clarified and strained RF. Inoculation rate was 10 ⁶ (clarified RF), 10⁷ (strained RF) (in the U.S.) and 10⁷, 10⁸ CFU ml⁻¹ in Israel (strained RF). The inoculated RF was incubated for 72 and 96 h at 39°C, with and without 5 g 1⁻¹ glucose. Changes in pH, LAB numbers and fermentation products were monitored throughout the incubation period. The results indicated that LAB silage inoculants can survive in RF. The inoculants with the highest counts after 72 h incubation in rumen fluid were Lactobacillus plantarum MTD1 and a L. plantarum/P. cerevisiae mixture (USA) and Enterococcus faecium strains and Lactobacillus buchneri (Israel). Incubation of rumen fluid with silage LAB inoculants resulted in higher pH values in most cases as compared with that of un-inoculated controls. The magnitude of the effect varied among inoculants and typically was enhanced with the inoculants that survived best. This might suggest the mode of action of LAB silage inoculants in the rumen as higher pH enhances fibrolytic microorganisms in the rumen. Volatile fatty acid (VFA) concentrations in the inoculated RF tended to be lower than in the control RF after incubation. However, L. plalltarull1 MTDI resulted in the highest concentrations of VFA in the RF relative to other inoculants. The implication of this result is not as yet clear. In previous research by others, feeding silages which were inoculated with this strain consistently enhanced animal performance. These finding were recently published in Weinberg et.al.. (2003), J. of Applied Microbiology 94:1066-1071 and in Weinberg et al.. (2003), Applied Biochemistry and Biotechnology (accepted). In addition, some strains in our studies have shown bacteriocins like activity. These included Pediococcus pentosaceus, Enterococcus faecium and Lactobacillus plantarum Mill 1. These results will enable us to continue the research with the LAB strains that survived best in the rumen fluid and have the highest potential to affect the rumen environment.
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Weinberg, Zwi G., Adegbola Adesogan, Itzhak Mizrahi, Shlomo Sela, Kwnag Jeong y Diwakar Vyas. effect of selected lactic acid bacteria on the microbial composition and on the survival of pathogens in the rumen in context with their probiotic effects on ruminants. United States Department of Agriculture, enero de 2014. http://dx.doi.org/10.32747/2014.7598162.bard.
Texto completoResumen
This research project was performed in context of the apparent probiotic effect of selected lactic acid bacteria (LAB) silage inoculants on the performance of ruminants (improved feed intake, faster live-weight gain, higher milk yields and improved feed efficiency). The overall objective was to find out how LAB affect ruminant performance. The project included several “chapters” as follows: 1. The effect of LAB silage inoculants on the survival of detrimental bacteria in rumen fluid, in vitro study (Weinberg et al., The Volcani Center). An in vitro model was developed to study the interaction between selected LAB and an E. coli strain tagged with green fluorescence protein (GFP) in buffered RF. Results indicated that both LAB inoculants and E. coli survived in the RF for several days; both LAB inoculants and LAB-treated silages did not affect survival of E. coli in rumen fluid in vitro. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the performance of high-lactating cows (Weinberg et al., The Volcani Center). Treatments included control (no additive), Lacobacillusbuchneri40788 (LB), Lactobacillus plantarumMTD1 40027 (LP) and Pediococcuspentosaceus30168 (PP), each applied at 10⁶ cfu/g FM. The silages were included in the TMR of 32 high milking Holstein cows in a controlled feeding experiment. All baled silages were of good quality. The LB silage had the numerically highest acetic acid and were the most stable upon aerobic exposure. The cows fed the LB silages had the highest daily milk yields, percent milk fat and protein. The microbiome of baled wheat silages and changes during ensiling of wheat and corn (Sela et al., The Volcani Center). Bacterial community of the baled silages was dominated mainly of two genera in total, dominated by Lactobacillus and Clostridium_sensu_stricto_12 with 300 other genera at very low abundance. Fungal community was composed mainly of two genera in total, dominated by Candida and Monascuswith 20 other genera at very low abundance. In addition, changes in the microbiome during ensiling of wheat and corn with and without addition of L. plantarumMTD1 was studied in mini-silos. Overall 236 bacterial genera were identified in the fresh corn but after 3 months Lactobacillus outnumbered all other species by acquiring 95% of relative abundance. The wheat silage samples are still under analysis. The effect of applying LAB inoculants at ensiling on survival of E. coli O157:H7 in alfalfa and corn silages(Adesogan et al., University of Florida). E. coli (10⁵ cfu/g) was applied to fresh alfalfa and corn at ensiling with or without L. plantarumor L. buchneri. The pathogen was added again after about 3 moths at the beginning of an aerobic exposure period. The inoculants resulted in faster decrease in pH as compared with the control (no additives) or E. coli alone and therefore, the pathogen was eliminated faster from these silages. After aerobic exposure the pathogen was not detected in the LAB treated silages, whereas it was still present in the E. coli alone samples. 5. The effect of feeding corn silage treated with or without L. buchnerion shedding of E. coli O157:H7 by dairy cows (Adesogan et al., UFL). BARD Report - Project 4704 Page 2 of 12 Five hundred cows from the dairy herd of the University of Florida were screened for E. coli shedding, out of which 14 low and 13 high shedders were selected. These cows were fed a total mixed ration (TMR) which was inoculated with E. coli O157:H7 for 21 days. The TMR included corn silage treated with or without L. buchneri. The inoculated silages were more stable upon aerobic exposure than the control silages; the silage inoculant had no significant effect on any milk or cow blood parameters. However, the silage inoculant tended to reduce shedding of E. coli regardless of high or low shedders (p = 0.06). 6. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the rumen microbiome (Mizrahi et al., BGU). Rumen fluid was sampled throughout the feeding experiment in which inoculated wheat silages were included in the rations. Microbial DNA was subsequently purified from each sample and the 16S rRNA was sequenced, thus obtaining an overview of the microbiome and its dynamic changes for each experimental treatment. We observed an increase in OTU richness in the group which received the baled silage inoculated with Lactobacillus Plantarum(LP). In contrast the group fed Lactobacillus buchneri(LB) inoculated silage resulted in a significant decrease in richness. Lower OTU richness was recently associated in lactating cows with higher performance (Ben Shabatet al., 2016). No significant clustering could be observed between the different inoculation treatments and the control in non metric multi-dimentional scaling, suggesting that the effect of the treatments is not the result of an overall modulation of the microbiome composition but possibly the result of more discrete interactions. Significant phylum level changes in composition also indicates that no broad changes in taxa identity and composition occurred under any treatment A more discrete modulation could be observed in the fold change of several taxonomic groups (genus level analysis), unique to each treatment, before and after the treatment. Of particular interest is the LB treated group, in which several taxa significantly decreased in abundance. BARD Report - Project 4704 Page 3 of 12
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Dubcovsky, Jorge, Tzion Fahima y Ann Blechl. Positional cloning of a gene responsible for high grain protein content in tetraploid wheat. United States Department of Agriculture, septiembre de 2003. http://dx.doi.org/10.32747/2003.7695875.bard.
Texto completoResumen
High Grain Protein Content (GPC) is a desirable trait in breadmaking and pasta wheat varieties because of its positive effects on quality and nutritional value. However, selection for GPC is limited by our poor understanding of the genes involved in the accumulation of protein in the grain. The long-term goal of this project is to provide a better understanding of the genes controlling GPC in wheat. The specific objectives of this project were: a) to develop a high-density genetic map of the GPC gene in tetraploid wheat, b) to construct a T. turgidum Bacterial Artificial Chromosome (BAC) library, c) to construct a physical map of the GPC gene and identify a candidate for the GPC gene. A gene with a large effect on GPC was detected in Triticum turgidum var. dicoccoides and was previously mapped in the short arm of chromosome 6B. To define better the position of the Gpc-B1 locus we developed homozygous recombinant lines with recombination events within the QTL region. Except for the 30-cM region of the QTL these RSLs were isogenic for the rest of the genome minimizing the genetic variability. To minimize the environmental variability the RSLs were characterized using 10 replications in field experiments organized in a Randomized Complete Block Design, which were repeated three times. Using this strategy, we were able to map this QTL as a single Mendelian locus (Gpc-B1) on a 2.6-cM region flanked by RFLP markers Xcdo365 and Xucw67. All three experiments showed that the lines carrying the DIC allele had an average absolute increase in GPC of 14 g/kg. Using the RFLP flanking markers, we established the microcolinearity between a 2.l-cM region including the Gpc-B1 gene in wheat chromosome 6BS and a 350-kb region on rice chromosome 2. Rice genes from this region were used to screen the Triticeae EST collection, and these ESTs were used to saturate the Gpc-B1 region with molecular markers. With these new markers we were able to map the Gpc-B1 locus within a 0.3-cM region flanked by PCR markers Xucw83 and Xucw71. These flanking markers defined a 36-kb colinear region with rice, including one gene that is a potential candidate for the Gpc-B1 gene. To develop a physical map of the Gpc-B1 region in wheat we first constructed a BAC library of tetraploid wheat, from RSL#65 including the high Gpc-B1 allele. We generated half- million clones with an average size of l3l-kb (5.1 X genome equivalents for each of the two genomes). This coverage provides a 99.4% probability of recovering any gene from durum wheat. We used the Gpc-BI flanking markers to screen this BAC library and then completed the physical map by chromosome walking. The physical map included two overlapping BACs covering a region of approximately 250-kb, including two flanking markers and the Gpc-B1 gene. Efforts are underway to sequence these two BACs to determine if additional wheat genes are present in this region. Weare also developing new RSLs to further dissect this region. We developed PCR markers for flanking loci Xucw79andXucw71 to facilitate the introgression of this gene in commercial varieties by marker assisted selection (httQ://maswheat.ucdavis.edu/ orotocols/HGPC/index.hlm). Using these markers we introgressed the Gpc-B1 gene in numerous pasta and common wheat breeding lines.
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Funkenstein, Bruria y Shaojun (Jim) Du. Interactions Between the GH-IGF axis and Myostatin in Regulating Muscle Growth in Sparus aurata. United States Department of Agriculture, marzo de 2009. http://dx.doi.org/10.32747/2009.7696530.bard.
Texto completoResumen
Growth rate of cultured fish from hatching to commercial size is a major factor in the success of aquaculture. The normal stimulus for muscle growth in growing fish is not well understood and understanding the regulation of muscle growth in fish is of particular importance for aquaculture. Fish meat constitutes mostly of skeletal muscles and provides high value proteins in most people's diet. Unlike mammals, fish continue to grow throughout their lives, although the size fish attain, as adults, is species specific. Evidence indicates that muscle growth is regulated positively and negatively by a variety of growth and transcription factors that control both muscle cell proliferation and differentiation. In particular, growth hormone (GH), fibroblast growth factors (FGFs), insulin-like growth factors (IGFs) and transforming growth factor-13 (TGF-13) play critical roles in myogenesis during animal growth. An important advance in our understanding of muscle growth was provided by the recent discovery of the crucial functions of myostatin (MSTN) in controlling muscle growth. MSTN is a member of the TGF-13 superfamily and functions as a negative regulator of skeletal muscle growth in mammals. Studies in mammals also provided evidence for possible interactions between GH, IGFs, MSTN and the musclespecific transcription factor My oD with regards to muscle development and growth. The goal of our project was to try to clarify the role of MSTNs in Sparus aurata muscle growth and in particular determine the possible interaction between the GH-IGFaxis and MSTN in regulating muscle growth in fish. The steps to achieve this goal included: i) Determining possible relationship between changes in the expression of growth-related genes, MSTN and MyoD in muscle from slow and fast growing sea bream progeny of full-sib families and that of growth rate; ii) Testing the possible effect of over-expressing GH, IGF-I and IGF-Il on the expression of MSTN and MyoD in skeletal muscle both in vivo and in vitro; iii) Studying the regulation of the two S. aurata MSTN promoters and investigating the possible role of MyoD in this regulation. The major findings of our research can be summarized as follows: 1) Two MSTN promoters (saMSTN-1 and saMSTN-2) were isolated and characterized from S. aurata and were found to direct reporter gene activity in A204 cells. Studies were initiated to decipher the regulation of fish MSTN expression in vitro using the cloned promoters; 2) The gene coding for saMSTN-2 was cloned. Both the promoter and the first intron were found to be polymorphic. The first intron zygosity appears to be associated with growth rate; 3) Full length cDNA coding for S. aurata growth differentiation factor-l I (GDF-II), a closely related growth factor to MSTN, was cloned from S. aurata brain, and the mature peptide (C-terminal) was found to be highly conserved throughout evolution. GDF-II transcript was detected by RT -PCR analysis throughout development in S. aurata embryos and larvae, suggesting that this mRNA is the product of the embryonic genome. Transcripts for GDF-Il were detected by RT-PCR in brain, eye and spleen with highest level found in brain; 4) A novel member of the TGF-Bsuperfamily was partially cloned from S. aurata. It is highly homologous to an unidentified protein (TGF-B-like) from Tetraodon nigroviridisand is expressed in various tissues, including muscle; 5) Recombinant S. aurata GH was produced in bacteria, refolded and purified and was used in in vitro and in vivo experiments. Generally, the results of gene expression in response to GH administration in vivo depended on the nutritional state (starvation or feeding) and the time at which the fish were sacrificed after GH administration. In vitro, recombinantsaGH activated signal transduction in two fish cell lines: RTHI49 and SAFI; 6) A fibroblastic-like cell line from S. aurata (SAF-I) was characterized for its gene expression and was found to be a suitable experimental system for studies on GH-IGF and MSTN interactions; 7) The gene of the muscle-specific transcription factor Myogenin was cloned from S. aurata, its expression and promoter activity were characterized; 8) Three genes important to myofibrillogenesis were cloned from zebrafish: SmyDl, Hsp90al and skNAC. Our data suggests the existence of an interaction between the GH-IGFaxis and MSTN. This project yielded a great number of experimental tools, both DNA constructs and in vitro systems that will enable further studies on the regulation of MSTN expression and on the interactions between members of the GHIGFaxis and MSTN in regulating muscle growth in S. aurata.
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Lahav, Ori, Albert Heber y David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, marzo de 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
Texto completoResumen
The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.