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1
Woodward, Todd S., Beat Meier, Christine Tipper, and Peter Graf. "Bivalency is Costly: Bivalent Stimuli Elicit Cautious Responding." Experimental Psychology 50, no. 4 (October 2003): 233–38. http://dx.doi.org/10.1026//1618-3169.50.4.233.
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Abstract. When performing tasks in alternation, substantial slowing occurs when the stimuli have features relevant to both tasks (i.e., when stimuli are bivalent as opposed to univalent). One possible source of this slowing, herein called a bivalency cost, is that encountering bivalent stimuli leads to a more cautious response style. To investigate this, we employed a paradigm that required performing three simple tasks, with bivalent stimuli occasionally encountered on one task. The results show that regardless of the feature overlap among the stimuli used for the different tasks, the introduction of bivalent stimuli slowed responding on all tasks and it was accompanied by a decrease in response errors. Overall, it appears that bivalent stimuli recruit a more cautious approach to task-switching performance.
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Lavania, U. C., Sangeeta Srivastava, and J. Sybenga. "Cytogenetics of fertility improvement in artificial autotetraploids of Hyoscyamus niger L." Genome 34, no. 2 (April 1, 1991): 190–94. http://dx.doi.org/10.1139/g91-030.
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Genetically stable artificial autotetraploids with over 90% seed set were obtained by colchicine treatment of the solanaceous species Hyoscyamus niger L. (4x = 68). The tetraploids were vigorous and had earlier been shown to yield considerably more tropane alkaloid per individual than the source diploids. The tetraploids had high bivalent frequencies at meiosis, and high fertility as a result of the formation of genetically balanced gametes. There was a systematic and significant decrease in quadrivalent frequency and an increase in bivalent frequency in three subsequent generations tested (C0, C1, C2). Possible causes of high bivalent frequency are discussed. Seed fertility can probably be increased in advanced generations by further selection for fertility and maximization of heterozygosity.Key words: Hyoscyamus niger, autotetraploid, meiosis, bivalents, fertility, selection.
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Tymová, Petra, Iveta Skotnicova, and Zdenek Galda. "Identification of a Percentage of Engagement of the Bivalent Source of the Earth–Water Type Heat Pump in Heating of the School Using the DDFPM Method." Advanced Materials Research 1041 (October 2014): 135–38. http://dx.doi.org/10.4028/www.scientific.net/amr.1041.135.
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The calculation based on the DDFPM method will enable us to identify the percentage engagement of the bivalent source in heating of the facilities in the period under consideration and at the location under consideration and we will be able to verify an optimum design for covering the heat loss by the bivalent source of the heat pump.
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Tagiuri, Renato, and John Davis. "Bivalent Attributes of the Family Firm." Family Business Review 9, no. 2 (June 1996): 199–208. http://dx.doi.org/10.1111/j.1741-6248.1996.00199.x.
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Although family-owned and managed firms are the predominant form of business organization in the world today, little systematic research exists on these companies. This paper builds upon insights found in the emerging literature on these enterprises and upon our own observations to provide a conceptual framework to better understand these complex organizations. We introduce the concept of the Bivalent Attributes—a unique, inherent feature of an organization that is the source of both advantages and disadvantages— to explain the dynamics of the family firm.
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Kurbangaleeva, M. H., and R. H. Giniatullin. "Development of Аctions for Мinimization of Ions of Manganese in Sewage of Soda Production." Ecology and Industry of Russia 23, no. 2 (February 8, 2019): 48–51. http://dx.doi.org/10.18412/1816-0395-2019-2-48-51.
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It is studied and revealed sources of bivalent manganese in technological waters of soda production. It is established that a source of this component are raw materials - limestone and with increase in depth of development of breed the content of compounds of manganese increases. The further research on a technological chain of solid waste of soda production and observation wells in close proximity to sludge collectors has shown that the content of compounds of manganese doesn't exceed a natural background. Purification of technological waters of ions of manganese was carried out with use of reagents: potassium permanganate; sodium sulfide; suspension of weak limy milk. For purification of technological waters of ions of bivalent manganese suspension of weak limy milk is offered, at the same time cleaning of this component for 99,9 % is reached.
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Doseva, Nadezhda, and Daniela Chakyrova. "Life cycle cost analysis of different residential heat pump systems." E3S Web of Conferences 207 (2020): 01014. http://dx.doi.org/10.1051/e3sconf/202020701014.
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Nowadays, the application of air-source heat pumps for heating and cooling in residential buildings has been increased significantly. The main occasion for this is the accessibility of a heat source for these devices - the external air. Nevertheless, the increase of the energy efficiency of the air source heat pump systems is a difficult design problem because their capacity and performance are a function of the dynamically changing parameters of the outdoor air. Because of that, the main aim of this study is to develop an approach for choosing a structural scheme of an air-to-water heat pump system under specific climatic conditions. The considered systems are monovalent, bivalent-parallel and bivalent-alternative heat pump systems. In the current paper is conducted a dynamic energy modeling of heating and cooling demand of a typical residential building situated in Varna, Bulgaria and applying the bin temperature data. It is assessed the effect of the heat pump capacity over the annual and seasonal energy performance of the heat pump systems. It is established the effect of the bivalent temperature, cut-off temperature and on-off cycles duration on rates of the criteria for techno-economic assessment. The seasonal coefficient of performance (SCOP), seasonal energy efficiency rate (SEER) and life cycle costs (LCC) of the analyzed heat pump systems are adopted as assessment parameters.
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Köse, E., A. Prof Sauer, and C. Pelzel. "Energieflexibel durch bivalente Produktionsanlagen*/Energy flexibility through bivalent production facilities - Using bivalent production processes to reduce energy costs and stabilize the electricity grid." wt Werkstattstechnik online 107, no. 05 (2017): 366–72. http://dx.doi.org/10.37544/1436-4980-2017-05-62.
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Aufgrund der fluktuierenden Energieerzeugung aus regenerativen Energiequellen sind die Strompreise an der Börse zum Teil enormen Schwankungen unterworfen. Die hier modellierte bivalente Spritzgussmaschine kann bei Bedarf zwischen zwei Energieträgern wechseln. Die Berechnung des Instituts für Energieeffizienz in der Produktion (EEP) auf Basis der modellierten bivalenten Spritzgussmaschine zeigt, wie sich die Energiekosten durch einen Energieträgerwechsel verringern lassen, ohne die Produktion zu unterbrechen. Due to the fluctuating energy generation from renewable sources, electricity prices on the stock exchange are often subject to strong fluctuations. The bivalent injection molding machine modeled here can switch between two energy sources, if required. EEP‘s calculation based on the modeled bivalent injection molding machine shows how energy costs could be reduced by changing the energy supply without interrupting the production.
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Demiyan, V. V., E. A. Zelenskaya, and N. P. Shabelskaya. "Electrolytic Behavior of Nickel in Polarization by Variable Asymmetric Rectangular Current in Alkaline Solutions." Solid State Phenomena 299 (January 2020): 1010–16. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.1010.
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The paper presents experimental data on nickel oxidation during electrolysis under rectangular alternating current in alkaline solutions, when the cathode pulse (Iк ) is greater than the anode pulse ( Iа ). During the process, intense nickel destruction occurs forming bivalent oxide powder. Under prolonged electrolysis, this powder deposits at the bottom of the electrolyzer in the form of a sponge. The results obtained can be used to produce active mass in the porous nickel oxide electrode of a chemical current source.
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Hallam, T. J., R. Jacob, and J. E. Merritt. "Evidence that agonists stimulate bivalent-cation influx into human endothelial cells." Biochemical Journal 255, no. 1 (October 1, 1988): 179–84. http://dx.doi.org/10.1042/bj2550179.
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Human umbilical-vein endothelial cells stimulated with thrombin or histamine show an increase in [Ca2+]i (cytoplasmic free calcium concn.) that is maintained well above the basal pre-stimulated value as long as agonist and a source of extracellular Ca2+ are present. These results provide circumstantial evidence that agonists stimulate influx of Ca2+ across the plasma membrane and into the cytoplasm. Here, we have used Mn2+ as the extracellular bivalent cation which can bind to the fluorescent Ca2+ indicator fura-2 to quench its fluorescence completely. Human umbilical-vein endothelial cells were loaded with fura-2 and, in the presence of extracellular Mn2+, thrombin and histamine were shown to cause quenching of the intracellular dye. This result demonstrates conclusively that agonists can stimulate the influx of bivalent cations. Stimulated discharge of Ca2+ from intracellular stores and influx of Mn2+ were temporally resolved in the same cells to show that release of Ca2+ from intracellular stores clearly precedes influx. Influx of Mn2+ was also demonstrated when extracellular Mn2+ was added after agonist at a time when [Ca2+]i had fallen back to the basal value, showing that influx is not dependent on elevated [Ca2+]i.
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Boiko, O. P., O. M. Sen, B. M. Kurtiak, M. S. Romanovych, T. O. Pundiak, G. V. Sobko, and L. V. Romanovych. "Production testing of antigenicity and immunogenicity of bivalent inactivated vaccine salmonellosis vaccine." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 21, no. 96 (December 14, 2019): 28–32. http://dx.doi.org/10.32718/nvlvet9605.
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Scientists of both human and veterinary medicine combine their potential to develop new or improve old instruments in order to rein the problem of foodborne salmonellosis in Ukraine. According to the experience of European poultry industry, the most effective measure for the prevention of avian salmonellosis is total vaccination against salmonellosis of laying hens and breeding birds. In our country, the epizootic situation of salmonellosis of animals and poultry is consistently favorable. At the same moment nearly 90% of foods born Salmonella outbreaks are of poultry and egg products origin. In other words the source of major source of Salmonella agent is avian origin. Currently no vaccines of native origin have been registered in Ukraine. Although there have been numerous attempts to develop a vaccine against avian salmonellosis. The purpose of our work is to evaluate the antigenicity and immunogenicity of the two experimental series of bivalent inactivated emulsified vaccine against avian salmonellosis in production conditions. During the examination of the vaccine in the poultry farm it was found that for 21 days after the re-introduction of the vaccine, the titers of antibodies to the mono-antigens S. Typhimurium, Enteritidis and Gallinarum in the Agglutination Test (AT) and Indirect Hemagglutination Test (IH) were: 1 : 640–1280 to 1 : 2560–5120 respectively. This indicates high antigenicity of the vaccine. No significant difference between the levels of antibodies to Typhimurium and Enteritidis antigens was detected neither in AT nor IH. At the same time the levels of antibodies to mono-antigen Gallinarum were markedly lower in both reactions (1 : 160–1 : 320 – in AT and 1 : 320–1 : 1280 – in IH), but high enough to indicate that the vaccine creates a tense cross-humoral immunity to Salmonella surface antigens of Gallinarum serovar. The results of study of immunogenicity of the vaccine show that the vaccine is highly immunogenic. It means that after control infection of vaccinated hens none of tested Salmonella strains (S. Typhimurium and S. Enteritidis) were isolated from any organs, whereas in the control non-vaccinated group of birds both Salmonella test-strains were isolated from all organs. The obtained results provide a basis for further phases of the vaccine estimating followed by its registration in the prescribed manner.
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Malm, Maria, André Diessner, Kirsi Tamminen, Markus Liebscher, Timo Vesikari, and Vesna Blazevic. "Rotavirus VP6 as an Adjuvant for Bivalent Norovirus Vaccine Produced in Nicotiana benthamiana." Pharmaceutics 11, no. 5 (May 11, 2019): 229. http://dx.doi.org/10.3390/pharmaceutics11050229.
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Rotaviruses (RVs) and noroviruses (NoVs) are major causes of childhood acute gastroenteritis. During development of a combination vaccine based on NoV virus-like particles (VLP) and RV VP6 produced in baculovirus expression system in insect cells, a dual role of VP6 as a vaccine antigen and an adjuvant for NoV-specific immune responses was discovered. Here the VP6 adjuvant effect on bivalent GI.4 and GII.4-2006a NoV VLPs produced in Nicotiana benthamiana was investigated. BALB/c mice were immunized intradermally with suboptimal (0.3 µg) dose of each NoV VLP alone or combined with 10 µg of VP6, or equal doses of NoV VLPs and VP6 (1 µg/antigen). NoV-specific serum IgG antibodies and their blocking activity were analyzed using vaccine-homologous and heterologous NoV VLPs. Immunization with 0.3 µg NoV VLPs alone was insufficient to induce NoV-specific immune responses, but with co-administration of 10 µg of VP6, antibodies against vaccine-derived and heterologous NoV genotypes were generated. Furthermore, corresponding adjuvant effect of VP6 was observed with 1 µg dose. Efficient uptake and presentation of VP6 by dendritic cells was demonstrated in vitro. These results show that adjuvant effect of VP6 on bivalent NoV VLP vaccine is independent of the cell source used for vaccine production.
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Nguefack Marius Borel, Nguimezong, Josepha Foba-Tendo, Divine Mbom Yufanyi, Ekane Peter Etape, Jude Namanga Eko, and Lambi John Ngolui. "Averrhoa carambola: A Renewable Source of Oxalic Acid for the Facile and Green Synthesis of Divalent Metal (Fe, Co, Ni, Zn, and Cu) Oxalates and Oxide Nanoparticles." Journal of Applied Chemistry 2014 (September 17, 2014): 1–9. http://dx.doi.org/10.1155/2014/767695.
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A green, simple, and environmentally benign synthetic approach has been utilised to obtain some bivalent metal oxalates from Averrhoa carambola juice extract, without any purification or special treatment of the juice. The main acid components (oxalic acid and ascorbic acid) of the juice were identified by HPLC technique. The effect of temperature on the purity of the product has been investigated. The as-synthesized metal oxalates were thermally decomposed at low temperatures to their respective metal oxide nanoparticles. The metal oxalates and their respective thermal decomposition products were characterized by Fourier Transform Infrared spectroscopy, X-ray diffraction analysis, and thermogravimetry.
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Woo, Jung Hee, Yuan Yi Liu, Scott Stavrou, and David M. Neville. "Increasing Secretion of a Bivalent Anti-T-Cell Immunotoxin by Pichia pastoris." Applied and Environmental Microbiology 70, no. 6 (June 2004): 3370–76. http://dx.doi.org/10.1128/aem.70.6.3370-3376.2004.
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ABSTRACT The bivalent anti-T-cell immunotoxin A-dmDT390-bisFv(G4S) was developed for treatment of T-cell leukemia and autoimmune diseases and for tolerance induction for transplantation. This immunotoxin was produced extracellularly in toxin-sensitive Pichia pastoris JW102 (Mut+ ) under control of the AOX1 promoter. There were two major barriers to efficient immunotoxin production, the toxicity of the immunotoxin for P. pastoris and the limited capacity of P. pastoris to secrete the immunotoxin. The immunotoxin toxicity resulted in a decrease in the methanol consumption rate, cessation of cell growth, and low immunotoxin productivity after the first 22 h of methanol induction. Continuous cell growth and continuous immunotoxin secretion after the first 22 h of methanol induction were obtained by adding glycerol to the methanol feed by using a 4:1 methanol-glycerol mixed feed as an energy source and by continuously adding a yeast extract solution during methanol induction. The secretory capacity was increased from 22.5 to 37 mg/liter by lowering the induction temperature. A low temperature reduced the methanol consumption rate and protease activity in the supernatant but not cell growth. The effects of adding glycerol and yeast extract to the methanol feed were synergistic. Adding yeast extract primarily enhanced methanol utilization and cell growth, while adding glycerol primarily enhanced immunotoxin production. The synergy was further enhanced by decreasing the induction temperature from 23 to 15�C, which resulted in a robust process with a yield of 37 mg/liter, which was sevenfold greater than the yield previously reported for a toxin-resistant CHO cell expression system. This methodology should be applicable to other toxin-related recombinant proteins in toxin-sensitive P. pastoris.
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Mukherjee, Kalyan Kumar. "A comparative study of two cytotypes of Chenopodium album in West Bengal, India." Canadian Journal of Botany 64, no. 4 (April 1, 1986): 754–59. http://dx.doi.org/10.1139/b86-097.
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Two cytotypes, one diploid (2n = 18) and one hexaploid (2n = 54), of Chenopodium album L. were found in West Bengal. Morphological differences exist in the two cytotypes. Diploid plants were taller and had different flowering time, larger leaves, and lower saponin content in the seed as compared with the polyploid plants. Polyploidy is not associated with reduction of pollen fertility. A general uniformity in chromosome size, normal meiosis, bivalent formation, and regular seed setting in the polyploid suggest that homozygosity is a result of a continuous process of selection and evolution. Low saponin content and high protein content in the seed of the diploid may prove to be useful in breeding this variety as an alternative source of protein.
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Vladimír, Šimanský, Kolenčík Marek, and Puškelová L'ubica. "Effect of Carbonates and Bivalent Cations and Their Relationships with Soil Organic Matter from the View Point of Aggregate Formation." Agriculture (Pol'nohospodárstvo) 60, no. 3 (December 10, 2014): 77–86. http://dx.doi.org/10.2478/agri-2014-0009.
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Abstract The effect of carbonates on soil structure has not been sufficiently studied yet, despite the fact that in the literature their positive impact is mentioned mostly. Carbonates are the source of bivalent cations in soil solution and may be involved in stabilization of the aggregates, because negatively charged organic materials can be adsorbed onto the surface of clay by bivalent or polyvalent cations. We studied the effect of carbonates and bivalent cations and their relationships with soil organic matter (SOM) from the point of view of aggregate formation. The studies were carried out in several fields located on loamy Calcaric Chernozem, loamy Haplic and Mollic Fluvisols. The results showed that between exchangeable Mg2+ and water-stable macro-aggregates (WSAma) in size fractions >2 mm, positive correlations were found; however, the content of Mg2+ negative correlated with the contents of WSAma in <1 mm fractions as well as with waterstable micro-aggregates (WSAmi). The threshold limit for Mg2+ content for the formation of water-stable macro-aggregates was at 11.5 cmol/kg if all loamy soils were assessed together. A further increase resulted in a lower content of WSAma. If all investigated soils were assessed separately, these results did not enable us to distinguish the maximum formation of WSAma by Mg2+ in individual soils. We observed a positive correlation between the sum of basic exchangeable cations (SBC) as well as between cation exchange capacity (CEC) and larger size fractions of WSAma >2 mm; however, between SBC as well as CEC and smaller size fractions of WSAma >1 mm and WSAmi negative correlations were observed. Statistically significant negative correlations were observed between SOM content in WSA and carbonate content, and this effect was stronger in relation to the labile carbon. There were also positive correlations between SOM in WSA and SBC and CEC found if all loamy soils were assessed together.
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Jauhar, Prem P. "A reassessment of genome relationships between Thinopyrum bessarabicum and T. elongatum of the Triticeae." Genome 30, no. 6 (December 1, 1988): 903–14. http://dx.doi.org/10.1139/g88-146.
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Chromosome pairing and chiasma frequency in diploid (2n = 2x = 14; JE genomes), amphidiploid (2n = 4x = 28; JJEE), and triploid (2n = 3x = 21; JJE) hybrids between Thinopyrum bessarabicum (2n = 2x = 14; JJ) and T. elongatum (2n = 2x = 14; EE) were analyzed. The diploid hybrids (JE) showed a mean pairing of < 0.01V + 0.30IV + 0.28III + 4.98II + 1.97I with 8.36 chiasmata per cell. The pairing was rather poor, most bivalents being rod-shaped; some were clearly hetero-morphic and loosely paired (probably pseudochiasmate). The diploid hybrids were sterile, showing the reproductive isolation of the parental species. The JJE triploid had a mean chromosome configuration of < 0.01VI + 0.06IV + 1.53III + 5.46II + 5.20I with a chiasma frequency of 13.45 per cell. Chromosomes of the duplicated genome JJ showed preferential pairing, forming mostly ring bivalents with two or even three chiasmata each, as in the T. bessarabicum parent; most chromosomes of the E genome remained as univalents. Thus, the E genome chromosomes offered little synaptic competition to the chromosomes of the duplicated JJ genome. The degree of preferential pairing was even stronger in the JJEE amphidiploids, which predominantly showed bivalent pairing with up to 14 ring bivalents in some cells. They had a mean pairing of 0.01VI + 0.55IV + 0.26III + 11.75II + 1.42I; the mean quadrivalent frequency per cell varied from 0.10 to 1.53. Thus J and E genomes essentially maintained their meiotic integrity at the 4x level. This pattern of chromosome pairing in hybrids at different ploidies and the sterility of diploid hybrids show that J and E are distinct genomes and that there is little justification for merging them, as suggested by previous workers. The J and E are homoeologous at best. The merger of Lophopyrum (E genome) with the genus Thinopyrum (J genome) would be improper. Although the J and E genomes are close enough to permit some intergenomic gene flow, which may be exploited in plant breeding, they are certainly not close enough to have the same genomic designation. The JJEE amphidiploids are meiotically stable and may be a useful source of genes for wheat improvement.Key words: genome, meiosis, chromosome pairing, phylogenetic relationships, Thinopyrum, interspecific hybrid, autoallo-triploid, amphidiploid.
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Manavalan, Tamilvendan, Arulmani Manavalan, Shiyamsundar Ramachandran, and Klaus Heese. "Identification of a Novel Thermostable Alkaline Protease from Bacillus megaterium-TK1 for the Detergent and Leather Industry." Biology 9, no. 12 (December 16, 2020): 472. http://dx.doi.org/10.3390/biology9120472.
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An increased need by the green industry for enzymes that can be exploited for eco-friendly industrial applications led us to isolate and identify a unique protease obtained from a proteolytic Bacillus megaterium-TK1 strain from a seawater source. The extracellular thermostable serine protease was processed by multiple chromatography steps. The isolated protease displayed a relative molecular weight (MW) of 33 kDa (confirmed by zymography), optimal enzyme performance at pH 8.0, and maximum enzyme performance at 70 °C with 100% substrate specificity towards casein. The proteolytic action was blocked by phenylmethylsulfonyl fluoride (PMSF), a serine hydrolase inactivator. Protease performance was augmented by several bivalent metal cations. The protease tolerance was studied under stringent conditions with different industrial dispersants and found to be stable with Surf Excel, Tide, or Rin detergents. Moreover, this protease could clean blood-stained fabrics and showed dehairing activity for cow skin with significantly reduced pollution loads. Our results suggest that this serine protease is a promising additive for various eco-friendly usages in both the detergent and leather industries.
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Kmita, H., O. Stobienia, and J. Michejda. "The access of metabolites into yeast mitochondria in the presence and absence of the voltage dependent anion selective channel (YVDAC1)." Acta Biochimica Polonica 46, no. 4 (December 31, 1999): 991–1000. http://dx.doi.org/10.18388/abp.1999_4124.
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Since yeast Saccharomyces cerevisiae mutants depleted of the voltage dependent anion selective channel (YVDAC1) are still able to grow on a non-fermentable carbon source, a functional transport system in the outer mitochondrial membrane must exist to support the access of metabolites into mitochondria. It was assumed that the properties of the system could be inferred from the differences in the results observed between wild type and mutant mitochondria since no crucial differences in this respect between the two types of mitoplasts were observed. YVDAC1-depleted mitochondria displayed a highly reduced permeability of the outer membrane, which was reflected in increased values of K0.5(NADH) for respiration and K0.5(ADP) for triggering phosphorylating state as well as in delayed action of carboxyatractylate (CATR) in inhibition of phosphorylating state. The parameters were chosen to express the accessibility of the applied species to the intermembrane space. The passage of the molecules through the outer membrane depleted of YVDAC1 could be partially improved in the presence of bivalent cations (Mg2+, Ca2+), as in their presence lower values of the calculated parameters were obtained. The restrictions imposed on the transport of molecules through the YVDAC1-depleted outer membrane resulted in a competition between them for the access to the intermembrane space as measured by changes in parameters observed for a given species in the presence of another one. The competition was stronger in the absence of Mg2+ and depended on charge and size of transported molecules, as the strongest competitor was CATR and the weakest one--NADH. Thus, it can be concluded that the transport system functioning in the absence of YVDAC1 is modulated by bivalent cations and charge as well as size of transported molecules. Since an increased level of respiration due to the dissipation of delta psi causes an increase of K0.5(NADH) in both wild type and YVDAC1-depleted mitochondria it is concluded that a common property of YVDAC1 and the system functioning in YVDAC1-depleted mitochondria seems to be the dependence of the capacity on the level of mitochondrial respiration.
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Bikchurina, T. I., E. K. Tomgorova, A. A. Torgasheva, V. A. Bagirov, N. A. Volkova, and P. M. Borodin. "Chromosome synapsis, recombination and epigenetic modification in rams heterozygous for metacentric chromosome 3 of the domestic sheep Ovis aries and acrocentric homologs of the argali Ovis ammon." Vavilov Journal of Genetics and Breeding 23, no. 3 (May 14, 2019): 355–61. http://dx.doi.org/10.18699/vj19.502.
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Hybridization of domestic animal breeds with their wild relatives is a promising method for increasing the genetic diversity of farm animals. Resource populations derived from the hybridization of various breeds of domestic sheep with mouflon and argali are an important source of breeding material. The karyotypes of argali and domestic sheep differ for a Robertsonian translocation, which occurred in the common ancestor of mouflon and domestic sheep (Ovis aries) due to the centric fusion of chromosomes 5 and 11 of the argali (O. ammon) into chromosome 3 of sheep. It is known that heterozygosity for translocation can lead to synapsis, recombination and chromosome segregation abnormalities in meiosis. Meiosis in the heterozygotes for translocation that distinguishes the karyotypes of sheep and argali has not yet been studied. We examined synapsis, recombination, and epigenetic modification of chromosomes involved in this rearrangement in heterozygous rams using immunolocalization of key proteins of meiosis. In the majority of cells, we observed complete synapsis between the sheep metacentric chromosome and two argali acrocentric chromosomes with the formation of a trivalent. In a small proportion of cells at the early pachytene stage we observed delayed synapsis in pericentromeric regions of the trivalent. Unpaired sites were subjected to epigenetic modification, namely histone H2A.X phosphorylation. However, by the end of the pachytene, these abnormalities had been completely eliminated. Asynapsis was replaced by a nonhomologous synapsis between the centromeric regions of the acrocentric chromosomes. By the end of the pachytene, the γH2A.X signal had been preserved only at the XY bivalent and was absent from the trivalent. The translocation trivalent did not differ from the normal bivalents of metacentric chromosomes for the number and distribution of recombination sites as well as for the degree of centromeric and crossover interference. Thus, we found that heterozygosity for the domestic sheep chromosome 3 and argali chromosomes 5 and 11 does not cause significant alterations in key processes of prophase I meiosis and, therefore, should not lead to a decrease in fertility of the offspring from interspecific sheep hybridization.
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NIGOU, Jérôme, and Gurdyal S. BESRA. "Characterization and regulation of inositol monophosphatase activity in Mycobacterium smegmatis." Biochemical Journal 361, no. 2 (January 8, 2002): 385–90. http://dx.doi.org/10.1042/bj3610385.
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Mycobacterium tuberculosis and related members of the genus Mycobacterium contain a number of inositol-based lipids, such as phosphatidylinositol mannosides, lipomannan and lipoarabinomannan. The synthesis of phosphatidylinositol in M. smegmatis is essential for growth and myo-inositol is a key metabolite for mycobacteria. Little is known about the biosynthesis of inositol in mycobacteria and the only known de novo pathway for myo-inositol biosynthesis involves a two-step process. First, cyclization of glucose 6-phosphate to afford myo-inositol 1-phosphate via inositol-1-phosphate synthase and, secondly, dephosphorylation of myo-inositol 1-phosphate by inositol monophosphatase (IMP) to afford myo-inositol. The following report examines IMP activity in M. smegmatis extracts, with regard to pH dependence, bivalent cation re quirement, univalent cation inhibition, regulation by growth and carbon source. We show that IMP activity, which is optimal at the end of the exponential growth phase in Sauton's medium, is Mg2+-dependent. Moreover, IMP activity is inhibited by Li+ and Na+, with Li+ also being able to inhibit growth of M. smegmatis in vivo. This study represents a first step in the delineation of myo-inositol biosynthesis in mycobacteria.
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Pusic, Milenko, and Milan Dimkic. "Comparative assessment of radial collector well elements with a new approach." Annales g?ologiques de la Peninsule balkanique, no. 78 (2017): 37–45. http://dx.doi.org/10.2298/gabp1778037p.
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In radial collector well design or rehabilitation it is extremely important to define the capacity of the location and the long-term sustainable discharge of the well. Where incrustation occurs, groundwater entrance velocities at horizontal screens also need to be determined. At Belgrade Groundwater Source, maximum permissible screen entrance velocities are correlated with the oxic state of the aquifer, expressed via the redox potential, and the concentration of bivalent iron in the groundwater. The entrance velocities limit the rate of screen incrustation and are based on the maximum permissible increase in local hydraulic resistance at the screens. This is a novel approach on a global scale. In the case of anoxic groundwater, the derived permissible entrance velocities are much lower than estimated by standard, commonly used methods. The new approach is believed to be a significant contribution to well design. Jaroslav Cerni Institute for the Development of Water Resources (JCI) has developed software for estimating 3D groundwater flow, which relatively easily and realistically simulates horizontal screens and riverbed configuration and conductivity. The software is an effective tool for determining the capacity of the location and of the radial collector well itself. It is especially useful where the aquifer system comprises a semi-permeable interbed between the water-bearing layer, in which the screens are emplaced, and the overlying strata. Acomparative hydrodynamic analysis of two wells at Belgrade Groundwater Source is presented in the paper. One of the wells (RB-16) clearly reflects the presence of a semi-permeable interbed, whereas the other (RB-46) does not.
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Sohrabi-Jahromi, Salma, and Johannes Söding. "Thermodynamic modeling reveals widespread multivalent binding by RNA-binding proteins." Bioinformatics 37, Supplement_1 (July 1, 2021): i308—i316. http://dx.doi.org/10.1093/bioinformatics/btab300.
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Abstract Motivation Understanding how proteins recognize their RNA targets is essential to elucidate regulatory processes in the cell. Many RNA-binding proteins (RBPs) form complexes or have multiple domains that allow them to bind to RNA in a multivalent, cooperative manner. They can thereby achieve higher specificity and affinity than proteins with a single RNA-binding domain. However, current approaches to de novo discovery of RNA binding motifs do not take multivalent binding into account. Results We present Bipartite Motif Finder (BMF), which is based on a thermodynamic model of RBPs with two cooperatively binding RNA-binding domains. We show that bivalent binding is a common strategy among RBPs, yielding higher affinity and sequence specificity. We furthermore illustrate that the spatial geometry between the binding sites can be learned from bound RNA sequences. These discovered bipartite motifs are consistent with previously known motifs and binding behaviors. Our results demonstrate the importance of multivalent binding for RNA-binding proteins and highlight the value of bipartite motif models in representing the multivalency of protein-RNA interactions. Availability and implementation BMF source code is available at https://github.com/soedinglab/bipartite_motif_finder under a GPL license. The BMF web server is accessible at https://bmf.soedinglab.org. Supplementary information Supplementary data are available at Bioinformatics online.
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Espinoza, Francisco, and Camilo L. Quarín. "Cytoembryology of Paspalum chaseanum and Sexual Diploid Biotypes of Two Apomictic Paspalum Species." Australian Journal of Botany 45, no. 5 (1997): 871. http://dx.doi.org/10.1071/bt96055.
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This study was undertaken to determine the cytology, method of reproduction, and flowering behaviour of three Paspalum species. Paspalum plicatulum has long been considered a segmental allotetraploid that reproduces by obligate apomixis with the type being apospory followed by pseudogamy. Paspalum simplex is an apomictic autotetraploid species, while P. chaseanum is a rare species for which no information regarding cytology and reproduction is available. This investigation concerns diploid cytotypes (2n = 2x = 20) of P. plicatulum and P. simplex that were recently collected in subtropical South America. In addition, two accessions of P. chaseanum were also recorded and both had 2n = 2x = 20 chromosomes. Meiosis showed regular bivalent chromosome pairing. Embryological observations indicated that the three species reproduce sexually at the diploid level. Pollen–pistil interaction following self-pollination suggested the presence of a self-incompatibility system responsible for allogamy. The results indicate that P. plicatulum and P. simplex complexes consist of diploid sexual allogamous cytotypes in addition to the known tetraploid apomictic cytotypes. Diploid strains constitute a source of sexuality for plant improvement. Chromosome doubling will likely produce sexual tetraploids to be used as females in crosses with natural apomictic tetraploid biotypes. Since diploid self-incompatible sexual Paspalum plants usually have apomictic tetraploid co-specific counterparts, the self-incompatible diploid P. chaseanum described in this study warrants further exploration for its apomictic counterpart.
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Han, Bing, Wei Xu, Naeem Ahmed, Anmin Yu, Zaiqing Wang, and Aizhong Liu. "Changes and Associations of Genomic Transcription and Histone Methylation with Salt Stress in Castor Bean." Plant and Cell Physiology 61, no. 6 (March 18, 2020): 1120–33. http://dx.doi.org/10.1093/pcp/pcaa037.
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Abstract Soil salinity is a major source of abiotic plant stress, adversely affecting plant growth, development and productivity. Although the physiological and molecular mechanisms that underlie plant responses to salt stress are becoming increasingly understood, epigenetic modifications, such as histone methylations and their potential regulation of the transcription of masked genes at the genome level in response to salt stress, remain largely unclear. Castor bean, an important nonedible oil crop, has evolved the capacity to grow under salt stress. Here, based on high-throughput RNA-seq and ChIP-seq data, we systematically investigated changes in genomic transcription and histone methylation using typical histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 tri-methylated lysine 27 (H3K27me3) markers in castor bean leaves subjected to salt stress. The results showed that gain or loss of histone methylation was closely associated with activated or repressed gene expression, though variations in both transcriptome and histone methylation modifications were relatively narrow in response to salt stress. Diverse salt responsive genes and switched histone methylation sites were identified in this study. In particular, we found for the first time that the transcription of the key salt-response regulator RADIALIS-LIKE SANT (RSM1), a MYB-related transcription factor involved in ABA(abscisic acid)-mediated salt stress signaling, was potentially regulated by bivalent H3K4me3-H3K27me3 modifications. Combining phenotypic variations with transcriptional and epigenetic changes, we provide a comprehensive profile for understanding histone modification, genomic transcription and their associations in response to salt stress in plants.
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Kutzner, Tanja J., Adele Gabba, Forrest G. FitzGerald, Nadezhda V. Shilova, Gabriel García Caballero, Anna-Kristin Ludwig, Joachim C. Manning, et al. "How altering the modular architecture affects aspects of lectin activity: case study on human galectin-1." Glycobiology 29, no. 8 (May 15, 2019): 593–607. http://dx.doi.org/10.1093/glycob/cwz034.
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Abstract Discoveries on involvement of glycan–protein recognition in many (patho)physiological processes are directing attention to exploring the significance of a fundamental structural aspect of sugar receptors beyond glycan specificity, i.e., occurrence of distinct types of modular architecture. In order to trace clues for defining design–functionality relationships in human lectins, a lectin's structural unit has been used as source material for engineering custom-made variants of the wild-type protein. Their availability facilitates comparative analysis toward the stated aim. With adhesion/growth-regulatory human galectin-1 as example, the strategy of evaluating how changes of its design (here, from the homodimer of non-covalently associated domains to (i) linker-connected di- and tetramers and (ii) a galectin-3-like protein) affect activity is illustrated by using three assay systems of increasing degree of glycan complexity. Whereas calorimetry with two cognate disaccharides and array testing with 647 (glyco)compounds disclosed no major changes, galectin histochemical staining profiles of tissue sections that present natural glycome complexity revealed differences between wild-type and linker-connected homo-oligomers as well as between the galectin-3-like variant and wild-type galectin-3 for cell-type positivity, level of intensity at the same site and susceptibility for inhibition by a bivalent glycocompound. These results underscore the strength of the documented approach. Moreover, they give direction to proceed to (i) extending its application to other members of this lectin family, especially galectin-3 and (ii) then analyzing impact of architectural alterations on cell surface lattice formation and ensuing biosignaling systematically, considering the variants’ potential for translational medicine.
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Brunke, Sascha, and Bernhard Hube. "MfLIP1, a gene encoding an extracellular lipase of the lipid-dependent fungus Malassezia furfur." Microbiology 152, no. 2 (February 1, 2006): 547–54. http://dx.doi.org/10.1099/mic.0.28501-0.
Full textAbstract:
Malassezia furfur is a dimorphic fungus and a member of the normal cutaneous microflora of humans. However, it is also a facultative pathogen, associated with a wide range of skin diseases. One unusual feature of M. furfur is an absolute dependency on externally provided lipids which the fungus hydrolyses by lipolytic activity to release fatty acids necessary for both growth and pathogenicity. In this study, the cloning and characterization of the first gene encoding a secreted lipase of M. furfur possibly associated with this activity are reported. The gene, MfLIP1, shows high sequence similarity to other known extracellular lipases, but is not a member of a lipase gene family in M. furfur. MfLIP1 consists of 1464 bp, encoding a protein with a molecular mass of 54·3 kDa, a conserved lipase motif and an N-terminal signal peptide of 26 aa. By using a genomic library, two other genes were identified flanking MfLIP1, one of them encoding a putative secreted catalase, the other a putative amine oxidase. The cDNA of MfLIP1 was expressed in Pichia pastoris and the biochemical properties of the recombinant lipase were analysed. MfLip1 is most active at 40 °C and the pH optimum was found to be 5·8. The lipase hydrolysed lipids, such as Tweens, frequently used as the source of fatty acids in M. furfur media, and had minor esterase activity. Furthermore, the lipase is inhibited by different bivalent metal ions. This is the first molecular description of a secreted lipase from M. furfur.
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Ferreri, K., and K. M. J. Menon. "Characterization and isolation of a high-density-lipoprotein-binding protein from bovine corpus luteum plasma membrane." Biochemical Journal 287, no. 3 (November 1, 1992): 841–48. http://dx.doi.org/10.1042/bj2870841.
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The ovary uses the cholesterol from high-density lipoproteins (HDL) as a substrate source for steroid hormone production. It is not clear, however, how ovarian cells acquire the lipoprotein cholesterol. This study describes the characterization and isolation of a high-affinity-binding protein for apolipoprotein E-free HDL from the plasma-membrane fraction of bovine corpora lutea. Plasma membranes were prepared by differential centrifugation with 5-6-fold enrichment of 5′-nucleotidase activity. The binding of 125I-HDL to the plasma membranes was time-dependent, and there appeared to be a single high-affinity site with a Kd of 6.7 micrograms of HDL/ml of assay buffer. The binding was not affected by high concentrations of low-density lipoproteins or the Ca2+ chelator EDTA, nor by changes in pH in the range 6.5-9.0. The binding was affected by the salt concentration in the buffer, with a dose-dependent increase that reached a maximum at 150-250 mM-NaCl. Binding was increased in the presence of high concentrations of KCl and KBr, and most significantly increased by high concentrations of bivalent metal ions. Ligand-blot analysis under reducing conditions revealed that the binding protein was a single polypeptide of about 108 kDa that was associated with the plasma-membrane fraction. This HDL-binding protein was purified to homogeneity by solubilization with Triton X-100, poly(ethylene glycol) precipitation, DEAE-Sephadex chromatography, and preparative SDS/PAGE. The purified binding protein is a single polypeptide of 108 kDa that retains high affinity and specificity for HDL as assayed by ligand blotting.
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ZHANG, WEN-RAN, PAUL P. WANG, KARL E. PEACE, JUSTIN ZHAN, and YAN-QING ZHANG. "ON TRUTH, UNCERTAINTY, EQUILIBRIUM AND HARMONY — A TAXONOMY FOR YINYANG SCIENTIFIC COMPUTING." New Mathematics and Natural Computation 04, no. 02 (July 2008): 207–29. http://dx.doi.org/10.1142/s1793005708001033.
Full textAbstract:
Although modern scientific and technological advances derive computational power primarily from the classical evidence-based bottom-up cognition as founded by Greek philosopher Aristotle in his philosophy of science with a bivalent logic, the classical cognition, however, has met stiff challenges during the last few decades because of uncertainty faced by many new scientific endeavors. The holistic top-down nature of nanotechnology and brain modeling are just two of many examples. This new development points to the need for a critical review of the historical origins and distinctions of both top-down and bottom-up cognitions. This paper reviews the philosophy of science as founded by Aristotle (300BC), the Platonic realism as founded by Aristotle's teacher Plato (400BC-300BC), and the YinYang philosophy as founded by the ancient Chinese philosopher Laozi (or Laotze) (600BC). It is suggested that the long-standing unsettled dispute between Aristotle and Plato features a major source of uncertainty for both logic and mathematics. The authors hence propose a number of controversial philosophical and logical issues for debate. We advocate YinYang as an inspiration and unifying force for both top-down inductive and bottom-up deductive reasoning. We attempt to use an equilibrium-based YinYang bipolar dynamic logic (BDL) to bridge the gap between Aristotle and Plato as well as between logic and mathematics. Furthermore, we present a taxonomy for YinYang scientific computing with a classification of logical and statistical models for further discussion; we suggest that YinYang can be used as a catalyst for resolving certain "terminological difficulties" regarding truth, polarity, intuitionism, para-consistency, and fuzziness for equilibrium and harmony. A number of critical points are enumerated and discussed. An open challenge is posted.
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HILL, Craig M., and Ronald G. DUGGLEBY. "Mutagenesis of Escherichia coli acetohydroxyacid synthase isoenzyme II and characterization of three herbicide-insensitive forms." Biochemical Journal 335, no. 3 (November 1, 1998): 653–61. http://dx.doi.org/10.1042/bj3350653.
Full textAbstract:
Sulphonylurea and imidazolinone herbicides act by inhibiting acetohydroxyacid synthase (AHAS; EC 4.1.3.18), the enzyme that catalyses the first step in the biosynthesis of branched-chain amino acids. AHAS requires as cofactors thiamin diphosphate, a bivalent metal ion and, usually, FAD. Escherichia coli contains three isoenzymes and this study concerns isoenzyme II, the most herbicide-sensitive of the E. coli forms. A plasmid containing the large and small subunit genes of AHAS II was mutagenized using hydroxylamine and clones resistant to the sulphonylurea chlorimuron ethyl were selected. Three mutants were isolated; A26V, V99M and A108V. A26V has been described previously whereas the equivalent mutation of A108V has been reported in a herbicide-insensitive variant of yeast AHAS. The V99M mutation has not been discovered previously in AHAS from any source. The mutants were each over-expressed in E. coli, and the enzymes were purified to homogeneity. Some differences from wild type in the kinetic properties (kcat, Km and cofactor affinities) were observed, most notably a 28-fold decrease in the affinity for thiamin diphosphate of V99M. None of the mutants shows marked changes from the wild type in sensitivity to three imidazolinones, with the largest increase in the apparent inhibition constant being a factor of approximately 5. The A26V mutant is weakly resistant (6- to 20-fold) to six sulphonylureas, whereas stronger resistance is seen in V99M (20- to 250-fold) and A108V (35- to 420-fold). Resistance as a result of these mutations is consistent with a molecular model of the herbicide-binding site, which predicts that mutation of G249 might also confer herbicide insensitivity. Three G249 mutants were constructed, expressed and purified but all are inactive, apparently because they cannot bind FAD.
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Gilmour, R., C. F. Goodhew, G. W. Pettigrew, S. Prazeres, I. Moura, and J. J. G. Moura. "Spectroscopic characterization of cytochrome c peroxidase from Paracoccus denitrificans." Biochemical Journal 294, no. 3 (September 15, 1993): 745–52. http://dx.doi.org/10.1042/bj2940745.
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The cytochrome c peroxidase of Paracoccus denitrificans is similar to the well-studied enzyme from Pseudomonas aeruginosa. Like the Pseudomonas enzyme, the Paracoccus peroxidase contains two haem c groups, one high potential and one low potential. The high-potential haem acts as a source of the second electron for H2O2 reduction, and the low-potential haem acts as a peroxidatic centre. Reduction with ascorbate of the high-potential haem of the Paracoccus enzyme results in a switch of the low-potential haem to a high-spin state, as shown by visible and n.m.r. spectroscopy. This high-spin haem of the mixed-valence enzyme is accessible to ligands and binds CN- with a KD of 5 microM. The Paracoccus enzyme is significantly different from that from Pseudomonas in the time course of high-spin formation after reduction of the high-potential haem, and in the requirement for bivalent cations. Reduction with 1 mM ascorbate at pH 6 is complete within 2 min, and this is followed by a slow appearance of the high-spin state with a half-time of 10 min. Thus the process of reduction and spin state change can be easily separated in time and the intermediate form obtained. This separation is also evident in e.p.r. spectra, although the slow change involves an alteration in the low-spin ligation at this temperature rather than a change in spin state. The separation is even more striking at pH 7.5, where no high-spin form is obtained until 1 mM Ca2+ is added to the mixed-valence enzyme. The spin-state switch of the low-potential haem shifts the midpoint redox potential of the high-potential haem by 50 mV, a further indication of haem-haem interaction.
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Gallini, Luigi, Andrew Hursthouse, and Antonio Scopa. "Development and Validation of a Box and Flux Model to Describe Major, Trace and Potentially Toxic Elements (PTEs) in Scottish Soils." International Journal of Environmental Research and Public Health 18, no. 17 (August 25, 2021): 8930. http://dx.doi.org/10.3390/ijerph18178930.
Full textAbstract:
The box and flux model is a mathematical tool used to describe and forecast the major and trace elements perturbations of the Earth biogeochemical cycles. This mathematical tool describes the biogeochemical cycles, using kinetics of first, second and even third order. The theory and history of the box and flux modeling are shortly revised and discussed within the framework of Jim Lovelok’s Gaia theory. The objectives of the investigation were to evaluate the natural versus anthropic load of Potentially Toxic Elements (PTEs) of the Scottish soils, investigate the soil components adsorbing and retaining the PTEs in non-mobile species, evaluate the aging factor of the anthropic PTEs and develop a model which describes the leaching of PTEs in layered soils. In the Scottish land, the soil-to-rock enrichment factorinversely correlates with the boiling point of the PTEs. The same is observed in NW Italy and USA soils, suggesting the common source of the PTEs. The residence time in soils of the measured PTEs linearly correlates with the Soil Organic Matter (SOM). The element property which mostly explains the adsorption capacity for PTEs’ is the ionic potential (IP). The downward migration rates of the PTEs inversely correlate with SOM, and in Scottish soil, they range from 0.5 to 2.0 cm·year−1. Organic Bentoniteis the most important soil phase adsorbing cation bivalent PTEs. The self-remediation time of the polluted soil examined ranged from 50 to 100 years. The aging factor, the adsorption of PTEs’ into non-mobile species, and occlusion into the soil mineral lattice was not effective. The box and flux model developed, tested and validatedhere does not describe the leaching of PTEs following the typical Gaussian shape distribution of the physical diffusion models. Indeed, the mathematical model proposed is sensitive to the inhomogeneity of the layered soils.
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Hutchings, Carmel, Satish Kumar Rajasekharan, Ram Reifen, and Moshe Shemesh. "Mitigating Milk-Associated Bacteria through Inducing Zinc Ions Antibiofilm Activity." Foods 9, no. 8 (August 11, 2020): 1094. http://dx.doi.org/10.3390/foods9081094.
Full textAbstract:
Dairy products are a sector heavily impacted by food loss, often due to bacterial contaminations. A major source of contamination is associated with the formation of biofilms by bacterial species adopted to proliferate in milk production environment and onto the surfaces of milk processing equipment. Bacterial cells within the biofilm are characterized by increased resistance to unfavorable environmental conditions and antimicrobial agents. Members of the Bacillus genus are the most commonly found spoilage microorganisms in the dairy environment. It appears that physiological behavior of these species is somehow depended on the availability of bivalent cations in the environment. One of the important cations that may affect the bacterial physiology as well as survivability are Zn2+ ions. Thus, the aim of this study was to examine the antimicrobial effect of Zn2+ ions, intending to elucidate the potential of a zinc-based antibacterial treatment suitable for the dairy industry. The antimicrobial effect of different doses of ZnCl2 was assessed microscopically. In addition, expression of biofilm related genes was evaluated using RT-PCR. Analysis of survival rates following heat treatment was conducted in order to exemplify a possible applicative use of Zn2+ ions. Addition of zinc efficiently inhibited biofilm formation by B. subtilis and further disrupted the biofilm bundles. Expression of matrix related genes was found to be notably downregulated. Microscopic evaluation showed that cell elongation was withheld when cells were grown in the presence of zinc. Finally, B. cereus and B. subtilis cells were more susceptible to heat treatment after being exposed to Zn2+ ions. It is believed that an anti-biofilm activity, expressed in downregulation of genes involved in construction of the extracellular matrix, would account for the higher sensitivity of bacteria during heat pasteurization. Consequently, we suggest that Zn2+ ions can be of used as an effective antimicrobial treatment in various applications in the dairy industry, targeting both biofilms and vegetative bacterial cells.
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KIM, Seonghun, and Sun Bok LEE. "Identification and characterization of Sulfolobus solfataricusD-gluconate dehydratase: a key enzyme in the non-phosphorylated Entner–Doudoroff pathway." Biochemical Journal 387, no. 1 (March 22, 2005): 271–80. http://dx.doi.org/10.1042/bj20041053.
Full textAbstract:
The extremely thermoacidophilic archaeon Sulfolobus solfataricus utilizes D-glucose as a sole carbon and energy source through the non-phosphorylated Entner–Doudoroff pathway. It has been suggested that this micro-organism metabolizes D-gluconate, the oxidized form of D-glucose, to pyruvate and D-glyceraldehyde by using two unique enzymes, D-gluconate dehydratase and 2-keto-3-deoxy-D-gluconate aldolase. In the present study, we report the purification and characterization of D-gluconate dehydratase from S. solfataricus, which catalyses the conversion of D-gluconate into 2-keto-3-deoxy-D-gluconate. D-Gluconate dehydratase was purified 400-fold from extracts of S. solfataricus by ammonium sulphate fractionation and chromatography on DEAE-Sepharose, Q-Sepharose, phenyl-Sepharose and Mono Q. The native protein showed a molecular mass of 350 kDa by gel filtration, whereas SDS/PAGE analysis provided a molecular mass of 44 kDa, indicating that D-gluconate dehydratase is an octameric protein. The enzyme showed maximal activity at temperatures between 80 and 90 °C and pH values between 6.5 and 7.5, and a half-life of 40 min at 100 °C. Bivalent metal ions such as Co2+, Mg2+, Mn2+ and Ni2+ activated, whereas EDTA inhibited the enzyme. A metal analysis of the purified protein revealed the presence of one Co2+ ion per enzyme monomer. Of the 22 aldonic acids tested, only D-gluconate served as a substrate, with Km=0.45 mM and Vmax=0.15 unit/mg of enzyme. From N-terminal sequences of the purified enzyme, it was found that the gene product of SSO3198 in the S. solfataricus genome database corresponded to D-gluconate dehydratase (gnaD). We also found that the D-gluconate dehydratase of S. solfataricus is a phosphoprotein and that its catalytic activity is regulated by a phosphorylation–dephosphorylation mechanism. This is the first report on biochemical and genetic characterization of D-gluconate dehydratase involved in the non-phosphorylated Entner–Doudoroff pathway.
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Atlagic, J., V. Secerov-Fiser, and R. Marinkovic. "Interspecific hybridisation and cytogenetic studies in ornamental sunflower breeding." Australian Journal of Experimental Agriculture 45, no. 1 (2005): 93. http://dx.doi.org/10.1071/ea01109.
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This study examined the possibility of using wild sunflower species as a source of desirable genes in breeding the common ornamental sunflower. Crossing 7 wild species with 6 inbred lines of common ornamental sunflower produced F1 hybrid plants only with Helianthus argophyllus and H. petiolaris. The F1’s exhibited the dominant phenotype of the wild species. Cytological analysis showed irregularities in meiosis and low pollen fertility in F1 hybrids. The most frequent configuration was 15 bivalents and 1 quadrivalent and 13 bivalents and 2 quadrivalents. The presence of quadrivalents at diakinesis indicated the occurrence of translocations. In a small percentage of anaphase I meiocytes, chromosome bridges were detected resulting from inversions. The occurrence of translocations and inversions showed the differences in chromosome structure among the crossed species. Helianthus argophyllus and H. petiolaris may be useful in ornamental sunflower breeding as valuable sources of desirable genes.
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Mantel, Charlie, and Hal E. Broxmeyer. "Embryonic Stem Cells Bypass Numerous Cell Cycle Checkpoints; Not Just G1." Blood 112, no. 11 (November 16, 2008): 1331. http://dx.doi.org/10.1182/blood.v112.11.1331.1331.
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Abstract It was recently demonstrated that human and mouse embryonic stem cells (ESC) have deficiencies in the mitotic spindle assembly checkpoint (SAC) and it’s uncoupling to apoptosis which leads to polyploidy (Mantel et.al. BLOOD10:4518; 2007), a source of genetic instability in ESC in-vitro. The G1 checkpoint is also absent in ESC, a fact already known. It was also shown that p53 phosphorylation is absent in SAC-bypassed murine ESC in contrast to somatic cells with intact checkpoints (Mantel, et.al. CELL CYCLE 7:484; 2008). This lack of p53 phosporylation likely contributes to apoptosis uncoupling and polyploidization in ESC after microtubule/spindle damage and SAC-bypass. Microtubule/spindle damage in somatic cells eventually causes M-phase slippage where cells enter a 4C-G1 state that has 4C DNA content, no cyclin B1, and highly phosphorylated Rb. 4C-G1 status has not been investigated in ESC. We have now begun studies to determine mechanisms of checkpoint-bypass and polyploidization in ESC using intracellular flow cytometric analysis and here we report on the phosphorylation status of Rb in polyploid ESC. Because histone acetylation has been linked to cell cycle checkpoint function and because chromatin structure is more “open” in ESC, we investigated the oscillatory acetylations of the four core nucleosomal histones during checkpoint-bypass in ESC. The effects of DNA strand breaks on cell cycle checkpoints in ESC were also investigated. Results demonstrated that Rb is highly phosphorylated at several sites when ESC are in a cell cycle phase consistent with that seen in somatic cells in 4C-G1 after microtubule damage. It is concluded that ESC polyploidization is accompanied by 4C-G1-exit without apoptosis, which contrasts to 4C-G1-exit in somatic cells that do initiate apoptosis. There were also pronounced differences in acetylation oscillations on histone H4 and histone H2B compared to histone H3 and histone H2A during checkpoint activation and bypass. Total histones increased linearly as DNA content increased, as expected. Bivalent histone acetylation/methylation site, histone H3K9, changed little during checkpoint-bypass. However, DNA strand breakage revealed that S, G2, and the following G1 DNA-damage checkpoints also appeared to be bypassed in ESC. Most unusual is the polyploidization after DNA strand breakage, which may be due to aborted G2/M phases, but not to SAC activation since DNA strand breakage is not known to activate the SAC. DNA damage caused polyploidy without accumulation of cells in 4C-G1, as noted by lack of Rb phosphorylation, lack of p53 phosphorylation (as previously determined), but with an increase in total p53 in all phases of the cell cycle including 8C/polyploid. We conclude that mouse ESC can bypass numerous cell cycle checkpoints and fail to couple them to apoptosis initiation. This could be related to differences in histone acetylation, Rb phosphorylation, and the absence of p53 phosphorylation when compared to results of similar studies of somatic cells. Bypass of numerous checkpoints is a likely source of genetic instability in ESC cultured in-vitro.
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Klausz, Katja, Amir Karimzadeh-Tabrizi, Malena Buck, Steffen Krohn, Anna-Kathrin Otte, Christian Kellner, Giorgio Alberto Croci, Wolfram Klapper, Matthias Peipp, and Martin Gramatzki. "Targeting the Glyco-Antigen CD75s with the Tetravalent, Fc-Engineered Antibody 'Ebu-141 Tetra' Induces Potent Killing of B Cell Lymphoma and Plasma Cell Tumors." Blood 132, Supplement 1 (November 29, 2018): 4178. http://dx.doi.org/10.1182/blood-2018-99-118068.
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Abstract While monoclonal antibodies (MoAb) are already well established for the treatment of B cell-derived malignancies and usually show a good safety profile, not all patients benefit and relapses may be a problem. In order to identify novel surface structures suitable for antibody-based therapies and to improve killing mechanisms, 'EBU-141 Tetra' was developed. The parental MoAb EBU-141 is of mouse IgMk isotype, was generated in our laboratory and recognizes the glyco-antigen CD75s (previously CDw75), which are α-2,6-sialylated lactosamines on cell surface glycoproteins and glycolipids. CD75s was found on normal mature B cells and subsets of T cells, but is also expressed on certain lymphatic and solid tumors, e.g. mature B cell lymphoma, pancreatic and prostate cancer cells. EBU-141 specifically binds to CD75s on most B cell lymphoma, including Burkitt's lymphoma, FL, DLBCL, MCL, CLL, and interestingly plasma cell tumors. In addition, EBU-141 showed reactivity on a few cases of peripheral T-cell lymphoma, whereas classical Hodgkin lymphomas were consistently negative. Previously a chimeric IgG1k antibody, chEBU-141, was derived from EBU-141. Compared to the parental IgM antibody, chEBU-141 showed strongly reduced binding avidity, but was moderately effective in triggering antibody-dependent cell-mediated cytotoxicity (ADCC) of mature B cell lymphoma and malignant plasma cells via recruitment of NK cells. However, chEBU-141 lacked the potent complement-dependent cytotoxicity (CDC) observed with the parental EBU-141 antibody. The aim of this study was to generate a tetravalent binding, Fc-engineered chEBU-141 IgG1 antibody with enhanced binding avidity for CD75s and potent effector functions for antibody-based therapy of mature B cell lymphomas and multiple myeloma. Using the variable regions of EBU-141, the chimeric IgG1κ antibody with a protein-engineered Fc and tetravalent binding properties, named 'EBU-141 Tetra', was generated. This MoAb and relevant controls were produced by transient transfection of 293T cells and purified from cell culture supernatants by affinity chromatography. Direct anti-tumor effects and Fc-mediated modes of action were investigated in cell proliferation assays and chromium release experiments using lymphoma and myeloma cell lines. Peripheral blood mononuclear cells and serum of healthy donors were used as source of human effector cells and complement in the cytotoxicity experiments. The 'EBU-141 Tetra' showed improved binding to CD75s on cell surface of mature B cell lymphoma as well as myeloma plasma cells compared to the bivalent binding chEBU-141 IgG1. The higher avidity for CD75s resulted in markedly improved ADCC activity of the 'EBU-141 Tetra' against Daudi Burkitt's lymphoma and U266 plasma cells with EC50 values in the picomolar range and higher maximum lysis rates. In addition, the 'EBU-141 Tetra' regained CDC activity of the parental EBU-141 and demonstrated efficient killing of Burkitt's lymphoma and myeloma cell lines with human serum as complement source. Thus, recruitment of immune effector cells and activation of the complement system are the main modes of action of the novel, tetravalent, chimeric, Fc-engineered antibody 'EBU-141 Tetra' antibody. Our findings further demonstrate that highly potent IgG-like antibodies against glycan-structures can be generated from mouse IgM antibodies and may open a new therapeutic window for therapy of patients with mature B cell lymphomas and multiple myeloma. Disclosures Klausz: Affimed: Research Funding. Otte:Affimed: Research Funding. Klapper:HTG Molecular Diagnostics, Inc.: Research Funding; Amgen: Honoraria, Research Funding; F.Hoffman-La Roche: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Regeneron: Honoraria, Research Funding. Peipp:Affimed: Research Funding. Gramatzki:Affimed: Research Funding.
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Atlagic, Jovanka, and Sreten Terzic. "Cytogenetic study of hexaploid species Helianthus tuberosus and its F1 and BC1F1 hybrids with cultivated sunflower, H. annuus." Genetika 38, no. 3 (2006): 203–13. http://dx.doi.org/10.2298/gensr0603203a.
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Helianthus tuberosus is a potential source of resistance to many disease-provoking pathogens. Three accessions of H. tuberosus were used in this research and they were crossed with cultivated sunflower. Six F] and two BC1F1 hybrid combinations were obtained. Analysis of meiosis was performed using aceto-carmine method (GEORGIEVA-TODOROVA, 1976) and pollen viability was determined by staining method of ALEXANDER (1969). Meiosis was regular in cultivated sunflower and the pollen viability was high (96.8-98.9%). Low percent of irregularities was found in the meiosis of H. tuberosus. Pollen viability was high (97.2-98.7%). Chromosome pairing was mostly regular in F1 hybrids (34 bivalents), but some meiocytes contained 28-32 bivalents with uni- and quadrivalents present. The percent of meiocytes with fast chromosomes in metaphase was 24.6-87.2, with lagging chromosomes in anaphase I 10.5-81.0 and in telophase 25.0-33.3. Chromosome bridges were detected in 0-9.9% of meiocytes in anaphase. Pollen viability in F1 hybrids ranged from 27.0 to 47.9%. In BC1F1 hybrids number of bivalents was 16-25, univalent 2-18 and multivalent 0-1. Although a triploid set of chromosomes (51) was expected in BC1F1 hybrids, number of chromosomes was 45-57. Pollen viability varied from 0 to 54.3%.
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Agustin, Clara, and Jagdip Singh. "Curvilinear Effects of Consumer Loyalty Determinants in Relational Exchanges." Journal of Marketing Research 42, no. 1 (February 2005): 96–108. http://dx.doi.org/10.1509/jmkr.42.1.96.56961.
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Drawing from need, motivation, and social exchange theories, this study conceptualizes and empirically examines the differential curvilinear effects of multiple determinants of loyalty intentions, including transactional satisfaction, trust, and value for relational exchanges. The authors conceptualize trust as a “motivator,” satisfaction as a “hygiene,” and value as a “bivalent” factor in consumer loyalty mechanisms. Using consumer data on relational exchanges in two different service contexts—retail clothing and nonbusiness airline travel—and accounting for different sources of error—namely, measurement, common method, and response style—the authors empirically investigate the hypothesized mechanisms. The data support the motivator, or the enhancing role of trust, and the hygiene, or the maintaining role of satisfaction, on loyalty intentions in both contexts. Although the authors also obtain consistent results for the influence of value, its role is aligned with a hygiene mechanism, not a bivalent mechanism. The authors contribute to the study of loyalty antecedents by (1) theoretically proposing the nature and shape of the influence of different loyalty determinants, (2) considering the simultaneous and differential effects of multiple determinants, and (3) drawing implications from the results for theory and managerial practice.
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Sadida, Faozia Faleha, and Ma Manchur. "Production and Optimization of Cellulase Activity of Thermomonospora Viridis Isolated From Rice Straw." Bangladesh Journal of Botany 50, no. 2 (June 18, 2021): 395–404. http://dx.doi.org/10.3329/bjb.v50i2.54097.
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A highly cellulolytic actinomycete SR1 was locally isolated from rice straw and provisionally identified as Thermomonospora viridis. Optimum pH, temperature, carbon and nitrogen sources for its cellulase production were 6.5, 35°C, Carboxymethyl cellulase (CMC) and yeast extract, respectively whereas those of cellulase activity were 7.5, 40°C, CMC and peptone respectively. The effects of various metal ions and different reductant and inhibitors on its cellulase activity were investigated. Univalent Ag+ was found to decrease the enzyme activity whereas increased by bivalent Mg2+. Ethylene diamine tetraacetic acid (EDTA) caused remarkable decrease of cellulase activity but β-Mercaptoethanol stimulated its cellulase activity.
Bangladesh J. Bot. 50(2): 395-404, 2021 (June)
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Stelly, David M., D. W. Altman, R. J. Kohel, T. S. Rangan, and E. Commiskey. "Cytogenetic abnormalities of cotton somaclones from callus cultures." Genome 32, no. 5 (October 1, 1989): 762–70. http://dx.doi.org/10.1139/g89-509.
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Somaclonal variation occurs among regenerants from tissue culture of many plant species. Our objective was to determine whether cytogenetic variation contributes to somaclonal variation in cotton (Gossyptum hirsutum L.,2n = 4x = 52). Of 117 somaclones of cotton regenerated from 18-month-old callus cultures of 'SJ-2' and 'SJ-5' cultivars, 35 were analyzed for meiotic abnormalities. The population of somaclones was extremely varied in phenotype, most plants being strikingly aberrant in phenotype. Fertility was generally poor: 84% failed to set bolls and only 5% set 10 or more bolls in a field environment. Only one of the somaclones (3%) formed 26 bivalents at metaphase I. Fourteen were nonsynaptic to partially synaptic at metaphase I. Synaptic abnormalities impaired fertility and precluded thorough metaphase analysis. Chromosome numbers obtained for 32 plants ranged from 49 to 53, and only 1 plant was hyperaneuploid. No plant was polyploid. Chromosomal abnormalities in plants with normal metaphase pairing included univalents, unequal bivalents, rod bivalents, trivalents, open quadrivalents, and centric fragments. Seventeen hypoaneuploid plants formed a V-shaped trivalent at metaphase I, constituting a high frequency of tertiary monosomy. The high frequencies of aneuploidy and tertiary monosomy indicate that cytogenetic anomalies are a major source of somaclonal variation in cotton. It is hypothesized that (i) primary cytogenetic events during cotton cell culture give rise to breakage – fusion – bridge (BFB) cycles, (ii) BFB cycles accrue during culture, (iii) BFB cycles cause loss of chromatin, and (iv) BFB cycles are resolved by the formation of stable tertiary chromosomes with mono-centric activity. The hypothesis accounts mechanistically for the coincidence of chromatin deficiencies and chromatin exchange involved implicitly in tertiary monosomy, as well as for the relatively high frequency of tertiary monosomy among somaclones.Key words: aneuploid, monosomic, synaptic, sterility, Gossypium.
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McCoy, T. J. "Interspecific hybridization of Medicago sativa L. and M. rupestris M. B. using ovule–embryo culture." Canadian Journal of Genetics and Cytology 27, no. 2 (April 1, 1985): 238–45. http://dx.doi.org/10.1139/g85-035.
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An ovule–embryo culture method was used to produce the first interspecific hybrids between alfalfa (Medicago sativa L.) and Medicago rupestris M. B. Culture of fertilized ovules from the cross diploid (2n = 2x = 16) M. sativa (jpjp) × diploid (2n = 2x = 16) M. rupestris began 14 days after pollination. After 5 days in culture, the interspecific hybrid embryo was removed and transferred to fresh medium, where development into a plant occurred. Forty-six M. sativa – M. rupestris F1 hybrids have been recovered using this technique. All but one of the 46 F1 hybrids were diploid (2n = 2x = 16); the only exception was tetraploid (2n = 4x = 32). The most frequent meiotic configurations observed in the F1 hybrid plants were eight bivalents or seven bivalents and two univalents, indicating significant homology between M. sativa and M. rupestris genomes. However, pollen stainability (0–12%) and pollen germination (0–6%) were extremely low. Similar to the production of the F1, no first backcross (BC1) plants were obtained from seed; however, the ovule–embryo culture method was found to be a very effective method for recovering BC1 plants and hundreds of BC1 plants have been produced. The BC1 plants from crossing the F1 with diploid M. sativa were predominantly diploid. Medicago rupestris can now be considered a potential germplasm source for alfalfa improvement. The ovule–embryo culture method represents the first successful recovery of Medicago interspecific hybrids via some form of embryo rescue. Importantly, it appears this technique can be applied to other interspecific hybrid combinations in the Medicago genus.Key words: Medicago, alfalfa, embryo culture, interspecific hybrid.
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Kot, Y. G., E. V. Kot, E. S. Morosova, E. E. Persky, M. A. Gritsenko, and N. I. Bulankina. "Comparison of gene expression of metallothioneins, ubiquitin and p53 in fibroblasts from lung and skin of rats of different age." Visnyk of Dnipropetrovsk University. Biology, medicine 6, no. 2 (September 24, 2015): 161–64. http://dx.doi.org/10.15421/021529.
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We studied gene expression of five metallothioneins (MT 1-5), ubiquitin and protein p53 and their products in fibroblasts culture of the skin and lungs of white rats of different ages (2 weeks, 1, 3, and 24 months) and determined its (metallothionein 1-5 types, ubiquitin, p53) product quantity. All these proteins are protective ones, but perform their functions by using different mechanisms. Metallothionein bind, transport and excrete ions of bivalent metals, ubiquitin controls the cleavage of the defective and short-lived proteins in the proteasome, protein p53 controls apoptosis, thus ensuring the genome stability. The similarity of age dynamics of gene expression of ubiquitin and MT of cells of both sources has been shown – maximum at 3 months. Expression of p53 gene has a difference: both in the skin and lungs expression increases up to 24 months. Product quantity of p53 has a minimum in the skin at 3 months and remains constant; in the lungs, this value has a maximum at 1 month.
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Dweikat, I. M., and P. M. Lyrene. "Induced Tetraploidy in a Vaccinium elliottii Facilitates Crossing with Cultivated Highbush Blueberry." Journal of the American Society for Horticultural Science 116, no. 6 (November 1991): 1063–66. http://dx.doi.org/10.21273/jashs.116.6.1063.
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A synthetic autotetraploid derived by colchicine treatment of a Vaccinium elliottii Chapm. plant (2n = 2x = 24) was used to study the effect of chromosome doubling on the ability of this noncultivated species to cross with the cultivated tetraploid highbush blueberry (V. corymbosum L.). Mean pollen germination was 28%1 for the autotetraploid plant, compared to 53% for the diploid V. elliottii plant. However, the number of seedlings obtained per flower pollinated on the tetraploid highbush cultivar O'Neal rose from 0.01 when diploid V. elliottii was the pollen source to 3.86 when pollen from the autotetraploid V. elliottii plant was used. Reciprocal crosses between diploid V. elliottii and its autotetraploid and selfs of the autotetraploid produced no seedlings. Meiotic irregularities, such as multivalent during metaphase, laggards, and unequal chromosome disjunction, were observed in the autotetraploid, but most chromosomes were associated as bivalents.
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Vaicekauskienė, Loreta. "The Social Meaning Potential of the Global English Based on Data from Different Communities." Taikomoji kalbotyra, no. 14 (December 28, 2020): 183–208. http://dx.doi.org/10.15388/taikalbot.2020.14.13.
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This paper describes the social value of the global English language as identified in the investigations of various communities worldwide and shows how the social meanings of English relate to each other in a broader ideological field universal for today’s locally global world. The notions of indexical field (Eckert 2008) and bivalent indexicality (Cotter, Valentinsson 2018) are applied in the analysis. The aim of the study is to synthesize results obtained by different researchers from different ideological and communicative contexts and to explore the indexical potential of English, including its local varieties and mixed speech styles. The study is based on a qualitative analysis of a corpus of secondary sources, consisting of a total of 74 scholarly publications from the Expanding Circle communities, which were published in English in 1990–2020 (most of them during the second decade of the 21st century).In total, more than 50 social meanings of the global English language have been identified. It is likely that the abundance of social associations with English is due to the strong first-order indexes. Hence, the social meanings were grouped into the following nine indexical categories based on the presumed first-order sociocultural indexicalities: British and American culture; International sphere; Technologies, science and education; Economic and social status; Personal capital; Youth; Popular culture and media; Urban sphere; and Male. Positive social meanings dominate the indexicalities, but for some of them, bivalent indexicality (presence of contradictory positive and negative values) has been recorded. Although there is much overlap between these relative categories, the constellation as a whole is interpreted as a complex of several separate and multivalent indexical fields. It is to be hoped that this study not only illustrates that the notion of indexical field is applicable for analysis of the imagined global community of users of English, but also provides a broader ideological context for further research of the social meaning-making potential of the global English language.
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Raphael, Brian H., Mallory J. Choudoir, Carolina Lúquez, Rafael Fernández, and Susan E. Maslanka. "Sequence Diversity of Genes Encoding Botulinum Neurotoxin Type F." Applied and Environmental Microbiology 76, no. 14 (May 28, 2010): 4805–12. http://dx.doi.org/10.1128/aem.03109-09.
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ABSTRACT Botulism due to type F botulinum neurotoxin (BoNT/F) is rare (<1% of cases), and only a limited number of clostridial strains producing this toxin type have been isolated. As a result, analysis of the diversity of genes encoding BoNT/F has been challenging. In this study, the entire bont/F nucleotide sequences were determined from 33 type F botulinum toxin-producing clostridial strains isolated from environmental sources and botulism outbreak investigations. We examined proteolytic and nonproteolytic Clostridium botulinum type F strains, bivalent strains, including Bf and Af, and Clostridium baratii type F strains. Phylogenetic analysis revealed that the bont/F genes examined formed 7 subtypes (F1 to F7) and that the nucleotide sequence identities of these subtypes differed by up to 25%. The genes from proteolytic (group I) C. botulinum strains formed subtypes F1 through F5, while the genes from nonproteolytic (group II) C. botulinum strains formed subtype F6. Subtype F7 was composed exclusively of bont/F genes from C. baratii strains. The region of the bont/F5 gene encoding the neurotoxin light chain was found to be highly divergent compared to the other subtypes. Although the bont/F5 nucleotide sequences were found to be identical in strains harboring this gene, the gene located directly upstream (ntnh/F) demonstrated sequence variation among representative strains of this subtype. These results demonstrate that extensive nucleotide diversity exists among genes encoding type F neurotoxins from strains with different phylogenetic backgrounds and from various geographical sources.
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Khavanov, Pavel, and Anatoly Chulenyov. "Energy-efficient solar power plants for autonomous heat supply in Russia." MATEC Web of Conferences 251 (2018): 03012. http://dx.doi.org/10.1051/matecconf/201825103012.
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In the complex of measures for energy saving, partial replacement and reduction of consumption of fossil energy and electricity, water heating solar installations for heating systems have long been in practice for small energy facilities. Solar energy is one of the most dynamically developing directions of use of renewable energy sources, especially the introduction of which are associated with climatic conditions and technical requirements of their application. The territory of Russia is located mainly in the cold climatic zone and in regions with a sharply continental climate in which the operation of water heating solar plants is justified and most rational in seasonal use, in this case, their technical operation is carried out mainly during the non-heating period of the year. In such installations, in a number of cases, it is possible to avoid the need to use “non-freezing” heat carriers, and therefore the thermal schemes of the plants are simpler in design and cheaper, since heat exchangers or bivalent storage tanks can be excluded to transfer heat from the antifreeze to the water of the heating circuit or hot water system.
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Liu, Huiping, Yi Dai, Dawn Chi, Shuai Huang, Haifeng Li, Yamei Duan, Wenguang Cao, Yong Gao, George Fedak, and Jianmin Chen. "Production and Molecular Cytogenetic Characterization of a Durum Wheat-Thinopyrum elongatum 7E Disomic Addition Line with Resistance to Fusarium Head Blight." Cytogenetic and Genome Research 153, no. 3 (2017): 165–73. http://dx.doi.org/10.1159/000486382.
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Wheatgrass, Thinopyrum elongatum (2n = 2x = 14, EE), is an important wild relative of wheat with many excellent traits, including resistance to Fusarium head blight (FHB), that can be used for durum wheat improvement. Through hybridization of the durum cultivar “Langdon” with the amphiploid 8801 (AABBEE), a disomic alien addition line (2n = 30) with a pair of Th. elongatum 7E chromosomes was obtained and confirmed using chromosome-specific molecular markers of Th. elongatum and genomic in situ hybridization (GISH). This line is meiotically and reproductively stable, generally forming 15 bivalents at meiosis including 14 pairs from Langdon and 1 from Th. elongatum with 2 chiasmata each as revealed by GISH analysis. At the adult growth stages under field conditions, this addition line shows high resistance to FHB, with less than 16% infection on visual observation in 2 years (2014 and 2015). This addition line is shorter in height and has narrower leaves and shorter spikes as compared to its parent Langdon. So the linkage group 7E might be a further source of wheat improvement by targeted introgression approaches.
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Kang, Min, Hou Shang Li, and Xiu Qing Fu. "Measurement of Electrochemical Machining Initial Gap Based on Machine Vision." Advanced Materials Research 230-232 (May 2011): 1190–94. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.1190.
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In order to measure the initial gap between the workpiece and tool-cathode in electrochemical machining, the measurement method based on machine vision was studied in this paper. First, the measurement system based on machine vision was established. The hardware of the system consisted of CCD camera, image data acquisition card, light source and computer. The software of the system was developed by VC++6.0. Then, the original digital image of electrochemical machining initial gap collected by the CCD camera system was changed into the contour of image through graying, bivalency, edge detection and segmentation. Through system calibration, the physical size of the gap was calculated. Finally, relative experiments were carried out. The experimental results validated the feasibility of the method which measures the electrochemical machining initial gap based on machine vision.
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Newsholme, P., A. A. Adogu, M. A. Soos, and C. N. Hales. "Complement-induced Ca2+ influx in cultured fibroblasts is decreased by the calcium-channel antagonist nifedipine or by some bivalent inorganic cations." Biochemical Journal 295, no. 3 (November 1, 1993): 773–79. http://dx.doi.org/10.1042/bj2950773.
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The effects of different extracellular cations or organic Ca(2+)-channel modulators on complement-induced changes in intracellular Ca2+ and cell death have been investigated in the transfected NIH-3T3 HIR 3.5 cell line, which overexpresses the human insulin receptor. Cells were incubated with mouse anti-(human insulin receptor) monoclonal antibodies before exposure to rabbit or human serum (sources of heterologous complement). Changes in intracellular Ca2+ were complement-dependent (measured by influx of 45Ca), as was cytotoxicity (monitored by leakage of lactate dehydrogenase into the culture supernatant). Addition of a dihydropyridine Ca(2+)-channel antagonist (nifedipine) or some bivalent inorganic cations caused inhibition of 45Ca entry via a novel channel distinct from endogenous voltage-gated Ca2+ channels. Nifedipine decreased, but conversely the addition of a phenylalkylamine Ca(2+)-channel antagonist (verapamil) or the inorganic Ca2+ agonists Ba2+ and Sr+ increased, complement-induced cytotoxicity. These agents had no effect on cell viability at the studied concentrations, in the absence of complement. It is concluded that complement-induced cytotoxicity is mediated by Ca2+ influx through novel specific transmembrane channels which are sensitive to the Ca(2+)-channel antagonist nifedipine, but otherwise show little resemblance to L- or T-type voltage-gated Ca2+ channels.
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White, Jeffrey, Erin Kovar, Tiffany Chambers, Kunj Sheth, Erin Peckham-Gregory, Marisol O’Neill, Peter Langlois, Carolina Jorgez, Philip Lupo, and Abhishek Seth. "Hypospadias Risk from Maternal Residential Exposure to Heavy Metal Hazardous Air Pollutants." International Journal of Environmental Research and Public Health 16, no. 6 (March 15, 2019): 930. http://dx.doi.org/10.3390/ijerph16060930.
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Objective: Investigate whether residential prenatal exposure to heavy metal hazardous air pollutants (HMHAPs) is associated with an increased risk of hypospadias. Methods: Data on non-syndromic hypospadias cases (n = 8981) and control patients delivered in Texas were obtained from the Texas Birth Defects Registry and matched 1:10 by birth year. Average exposure concentrations of HMHAPs were obtained from the 2005 U.S. Environmental Protection Agency National-Scale Air Toxics Assessment and categorized into quintiles. Odds ratios and 95% confidence intervals were estimated. STROBE reporting guidelines were followed. Results: We observed associations between hypospadias and prenatal HMHAP exposure. Manganese demonstrated significant increased risk of hypospadias at the medium, medium-high and high exposure quintiles; lead in the medium-high and high exposure quintiles. Cadmium, mercury and nickel demonstrated a significant inverted “U-shaped” association for exposures with significant associations in the medium and medium-high quintiles but not in the medium-low and high quintiles. Arsenic and chromium demonstrated a significant bivalent association for risk of hypospadias in a lower quintile as well as a higher quintile with non-significant intermediate quintiles. Conclusions: Using data from one of the world’s largest active surveillance birth defects registries, we identified significant associations between hypospadias and HMHAP exposures. These results should be used in counseling for maternal demographic risk factors as well as avoidance of heavy metals and their sources.