Journal articles: 'Obligate intracellular bacteria'

1

Otten, Christian, Matteo Brilli, Waldemar Vollmer, Patrick H. Viollier, and Jeanne Salje. "Peptidoglycan in obligate intracellular bacteria." Molecular Microbiology 107, no. 2 (December 12, 2017): 142–63. http://dx.doi.org/10.1111/mmi.13880.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

McOrist, Steven. "Obligate intracellular bacteria and antibiotic resistance." Trends in Microbiology 8, no. 11 (November 2000): 483–86. http://dx.doi.org/10.1016/s0966-842x(00)01854-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Raoult, Didier. "Antimicrobial activity against obligate intracellular bacteria." Trends in Microbiology 9, no. 1 (January 2001): 14. http://dx.doi.org/10.1016/s0966-842x(00)01861-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Bordenstein, Seth R., and William S. Reznikoff. "Mobile DNA in obligate intracellular bacteria." Nature Reviews Microbiology 3, no. 9 (August 10, 2005): 688–99. http://dx.doi.org/10.1038/nrmicro1233.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

McClure, Erin E., Adela S. Oliva Chávez, Dana K. Shaw, Jason A. Carlyon, Roman R. Ganta, Susan M. Noh, David O. Wood, et al. "Engineering of obligate intracellular bacteria: progress, challenges and paradigms." Nature Reviews Microbiology 15, no. 9 (June 19, 2017): 544–58. http://dx.doi.org/10.1038/nrmicro.2017.59.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Boichenko, M. N., E. O. Kravtsova, and V. V. Zverev. "Mechanism of intracellular bacterial parasitism." Journal of microbiology, epidemiology and immunobiology, no. 5 (November 21, 2019): 61–72. http://dx.doi.org/10.36233/0372-9311-2019-5-61-72.

Full text

Abstract:

Algorithm of intracellular bacterial parasitism does not depend on if bacterium is obligate or facultative intracellular parasite. Depending on replicative niche’s localization intracellular bacterial parasites are divided onto cellular and vacuolated. Rickettsia spp., Shigella spp., Chlamydia spp. and Listeria monocytogenes use cell’s machinery of actin polymerization during process of their intracellular parasitism. These bacteria possess some of effector’s proteins which contain domains identical to effector proteins from the host cell. Shigella spp. T3SS and autotransporter protein IscA provide this process together with spreading bacteria intra colonic epithelium. In contrast other intracellular bacterial parasites, Listeria monocytogenes switches from dissemination in cytosol to persist in vacuole. In case of Brucella spp. the leading role in the creation of a replicative niche and in the modulation of the innate immune response is played by effector proteins of fourth type secretory system (T4SS).

APA, Harvard, Vancouver, ISO, and other styles

7

Hooppaw, Anna J., and Derek J. Fisher. "A Coming of Age Story: Chlamydia in the Post-Genetic Era." Infection and Immunity 84, no. 3 (December 14, 2015): 612–21. http://dx.doi.org/10.1128/iai.01186-15.

Full text

Abstract:

Chlamydiaspp. are ubiquitous, obligate, intracellular Gram-negative bacterial pathogens that undergo a unique biphasic developmental cycle transitioning between the infectious, extracellular elementary body and the replicative, intracellular reticulate body. The primaryChlamydiaspecies associated with human disease areC. trachomatis, which is the leading cause of both reportable bacterial sexually transmitted infections and preventable blindness, andC. pneumoniae, which infects the respiratory tract and is associated with cardiovascular disease. Collectively, these pathogens are a significant source of morbidity and pose a substantial financial burden on the global economy. Past efforts to elucidate virulence mechanisms of these unique and important pathogens were largely hindered by an absence of genetic methods. Watershed studies in 2011 and 2012 demonstrated that forward and reverse genetic approaches were feasible withChlamydiaand that shuttle vectors could be selected and maintained within the bacterium. While these breakthroughs have led to a steady expansion of the chlamydial genetic tool kit, there are still roads left to be traveled. This minireview provides a synopsis of the currently available genetic methods forChlamydiaalong with a comparison to the methods used in other obligate intracellular bacteria. Limitations and advantages of these techniques will be discussed with an eye toward the methods still needed, and how the current state of the art for genetics in obligate intracellular bacteria could direct future technological advances forChlamydia.

APA, Harvard, Vancouver, ISO, and other styles

8

Zientz, Evelyn, Thomas Dandekar, and Roy Gross. "Metabolic Interdependence of Obligate Intracellular Bacteria and Their Insect Hosts." Microbiology and Molecular Biology Reviews 68, no. 4 (December 2004): 745–70. http://dx.doi.org/10.1128/mmbr.68.4.745-770.2004.

Full text

Abstract:

SUMMARY Mutualistic associations of obligate intracellular bacteria and insects have attracted much interest in the past few years due to the evolutionary consequences for their genome structure. However, much less attention has been paid to the metabolic ramifications for these endosymbiotic microorganisms, which have to compete with but also to adapt to another metabolism—that of the host cell. This review attempts to provide insights into the complex physiological interactions and the evolution of metabolic pathways of several mutualistic bacteria of aphids, ants, and tsetse flies and their insect hosts.

APA, Harvard, Vancouver, ISO, and other styles

9

Martinson, Vincent G., Ryan M. R. Gawryluk, Brent E. Gowen, Caitlin I. Curtis, John Jaenike, and Steve J. Perlman. "Multiple origins of obligate nematode and insect symbionts by a clade of bacteria closely related to plant pathogens." Proceedings of the National Academy of Sciences 117, no. 50 (November 30, 2020): 31979–86. http://dx.doi.org/10.1073/pnas.2000860117.

Full text

Abstract:

Obligate symbioses involving intracellular bacteria have transformed eukaryotic life, from providing aerobic respiration and photosynthesis to enabling colonization of previously inaccessible niches, such as feeding on xylem and phloem, and surviving in deep-sea hydrothermal vents. A major challenge in the study of obligate symbioses is to understand how they arise. Because the best studied obligate symbioses are ancient, it is especially challenging to identify early or intermediate stages. Here we report the discovery of a nascent obligate symbiosis in Howardula aoronymphium, a well-studied nematode parasite of Drosophila flies. We have found that H. aoronymphium and its sister species harbor a maternally inherited intracellular bacterial symbiont. We never find the symbiont in nematode-free flies, and virtually all nematodes in the field and the laboratory are infected. Treating nematodes with antibiotics causes a severe reduction in fly infection success. The association is recent, as more distantly related insect-parasitic tylenchid nematodes do not host these endosymbionts. We also report that the Howardula nematode symbiont is a member of a widespread monophyletic group of invertebrate host-associated microbes that has independently given rise to at least four obligate symbioses, one in nematodes and three in insects, and that is sister to Pectobacterium, a lineage of plant pathogenic bacteria. Comparative genomic analysis of this group, which we name Candidatus Symbiopectobacterium, shows signatures of genome erosion characteristic of early stages of symbiosis, with the Howardula symbiont’s genome containing over a thousand predicted pseudogenes, comprising a third of its genome.

APA, Harvard, Vancouver, ISO, and other styles

10

Libbing, Cassandra L., Adam R. McDevitt, Rea-Mae P. Azcueta, Ahila Ahila, and Minal Mulye. "Lipid Droplets: A Significant but Understudied Contributor of Host–Bacterial Interactions." Cells 8, no. 4 (April 15, 2019): 354. http://dx.doi.org/10.3390/cells8040354.

Full text

Abstract:

Lipid droplets (LDs) are cytosolic lipid storage organelles that are important for cellular lipid metabolism, energy homeostasis, cell signaling, and inflammation. Several bacterial, viral and protozoal pathogens exploit host LDs to promote infection, thus emphasizing the importance of LDs at the host–pathogen interface. In this review, we discuss the thus far reported relation between host LDs and bacterial pathogens including obligate and facultative intracellular bacteria, and extracellular bacteria. Although there is less evidence for a LD–extracellular bacterial interaction compared to interactions with intracellular bacteria, in this review, we attempt to compare the bacterial mechanisms that target LDs, the host signaling pathways involved and the utilization of LDs by these bacteria. Many intracellular bacteria employ unique mechanisms to target host LDs and potentially obtain nutrients and lipids for vacuolar biogenesis and/or immune evasion. However, extracellular bacteria utilize LDs to either promote host tissue damage or induce host death. We also identify several areas that require further investigation. Along with identifying LD interactions with bacteria besides the ones reported, the precise mechanisms of LD targeting and how LDs benefit pathogens should be explored for the bacteria discussed in the review. Elucidating LD–bacterial interactions promises critical insight into a novel host–pathogen interaction.

APA, Harvard, Vancouver, ISO, and other styles

11

Henríquez, Vitalia, María Verónica Rojas, and Sergio H. Marshall. "An Alternative Efficient Procedure for Purification of the Obligate Intracellular Fish Bacterial Pathogen Piscirickettsia salmonis." Applied and Environmental Microbiology 69, no. 10 (October 2003): 6268–71. http://dx.doi.org/10.1128/aem.69.10.6268-6271.2003.

Full text

Abstract:

ABSTRACT Piscirickettsia salmonis is an obligate intracellular bacterial pathogen of salmonid fish and the etiological agent of the aggressive disease salmonid rickettsial syndrome. Today, this disease, also known as piscirickettsiosis, is the cause of high mortality in net pen-reared salmonids in southern Chile. Although the bacteria can be grown in tissue culture cells, genetic analysis of the organism has been hindered because of the difficulty in obtaining P. salmonis DNA free from contaminating host cell DNA. In this report, we describe a novel procedure to purify in vitro-grown bacteria with iodixanol as the substrate to run differential centrifugation gradients which, combined with DNase I digestion, yield enough pure bacteria to do DNA analysis. The efficiency of the purification procedure relies on two main issues: semiquantitative synchrony of the P. salmonis-infected Chinook salmon embryo (CHSE-214) tissue culture cells and low osmolarity of iodixanol to better resolve bacteria from the membranous structures of the host cell. This method resulted in the isolation of intact piscirickettsia organisms and removed salmon and mitochondrial DNA effectively, with only 1.0% contamination with the latter.

APA, Harvard, Vancouver, ISO, and other styles

12

Drevets, Douglas A., Pieter J. M. Leenen, and Ronald A. Greenfield. "Invasion of the Central Nervous System by Intracellular Bacteria." Clinical Microbiology Reviews 17, no. 2 (April 2004): 323–47. http://dx.doi.org/10.1128/cmr.17.2.323-347.2004.

Full text

Abstract:

SUMMARY Infection of the central nervous system (CNS) is a severe and frequently fatal event during the course of many diseases caused by microbes with predominantly intracellular life cycles. Examples of these include the facultative intracellular bacteria Listeria monocytogenes, Mycobacterium tuberculosis, and Brucella and Salmonella spp. and obligate intracellular microbes of the Rickettsiaceae family and Tropheryma whipplei. Unfortunately, the mechanisms used by intracellular bacterial pathogens to enter the CNS are less well known than those used by bacterial pathogens with an extracellular life cycle. The goal of this review is to elaborate on the means by which intracellular bacterial pathogens establish infection within the CNS. This review encompasses the clinical and pathological findings that pertain to the CNS infection in humans and includes experimental data from animal models that illuminate how these microbes enter the CNS. Recent experimental data showing that L. monocytogenes can invade the CNS by more than one mechanism make it a useful model for discussing the various routes for neuroinvasion used by intracellular bacterial pathogens.

APA, Harvard, Vancouver, ISO, and other styles

13

Ogawa, Motohiko, Mamoru Takahashi, Minenosuke Matsutani, Nobuhiro Takada, Shinichi Noda, and Masayuki Saijo. "Obligate intracellular bacteria diversity in unfed Leptotrombidium scutellare larvae highlights novel bacterial endosymbionts of mites." Microbiology and Immunology 64, no. 1 (October 23, 2019): 1–9. http://dx.doi.org/10.1111/1348-0421.12745.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Nováková, Eva, Filip Husník, Eva Šochová, and Václav Hypša. "Arsenophonus and Sodalis Symbionts in Louse Flies: an Analogy to the Wigglesworthia and Sodalis System in Tsetse Flies." Applied and Environmental Microbiology 81, no. 18 (July 6, 2015): 6189–99. http://dx.doi.org/10.1128/aem.01487-15.

Full text

Abstract:

ABSTRACTSymbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated withMelophagus ovinus, a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites. Interestingly, the whole system provides a remarkable analogy to the association betweenGlossinaand its symbiotic bacteria. In both, the symbiotic systems are composed of an obligate symbiont and two facultative intracellular associates,SodalisandWolbachia. In addition, extracellularBartonellaresides in the gut ofMelophagus. However, the phylogenetic origins of the two obligate mutualist symbionts differ. InGlossina, the mutualisticWigglesworthiaappears to be a relatively isolated symbiotic lineage, whereas inMelophagus, the obligate symbiont originated within the widely distributedArsenophonuscluster. Although phylogenetically distant, the two obligate symbionts display several remarkably similar traits (e.g., transmission via the host's “milk glands” or similar pattern of genome reduction). To obtain better insight into the biology and possible role of theM. ovinusobligate symbiont, “CandidatusArsenophonus melophagi,” we performed several comparisons of its gene content based on assignments of the Cluster of Orthologous Genes (COG). Using this criterion, we show that within a set of 44 primary and secondary symbionts, “Ca. Arsenophonus melophagi” is most similar toWigglesworthia. On the other hand, these two bacteria also display interesting differences, such as absence of flagellar genes inArsenophonusand their presence inWigglesworthia. This finding implies that a flagellum is not essential for bacterial transmission via milk glands.

APA, Harvard, Vancouver, ISO, and other styles

15

Chafee, M. E., D. J. Funk, R. G. Harrison, and S. R. Bordenstein. "Lateral Phage Transfer in Obligate Intracellular Bacteria (Wolbachia): Verification from Natural Populations." Molecular Biology and Evolution 27, no. 3 (November 11, 2009): 501–5. http://dx.doi.org/10.1093/molbev/msp275.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Kent, Bethany N., Lisa J. Funkhouser, Shefali Setia, and Seth R. Bordenstein. "Evolutionary Genomics of a Temperate Bacteriophage in an Obligate Intracellular Bacteria (Wolbachia)." PLoS ONE 6, no. 9 (September 14, 2011): e24984. http://dx.doi.org/10.1371/journal.pone.0024984.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Winslow, Gary M., Eric Yager, Konstantin Shilo, Erin Volk, Andrew Reilly, and Frederick K. Chu. "Antibody-Mediated Elimination of the Obligate Intracellular Bacterial Pathogen Ehrlichia chaffeensisduring Active Infection." Infection and Immunity 68, no. 4 (April 1, 2000): 2187–95. http://dx.doi.org/10.1128/iai.68.4.2187-2195.2000.

Full text

Abstract:

ABSTRACT It is generally accepted that cellular, but not humoral immunity, plays an important role in host defense against intracellular bacteria. However, studies of some of these pathogens have provided evidence that antibodies can provide immunity if present during the initiation of infection. Here, we examined immunity against infection byEhrlichia chaffeensis, an obligate intracellular bacterium that causes human monocytic ehrlichiosis. Studies with mice have demonstrated that immunocompetent strains are resistant to persistent infection but that SCID mice become persistently and fatally infected. Transfer of immune serum or antibodies obtained from immunocompetent C57BL/6 mice to C57BL/6 scid mice provided significant although transient protection from infection. Bacterial clearance was observed when administration occurred at the time of inoculation or well after infection was established. The effect was dose dependent, occurred within 2 days, and persisted for as long as 2 weeks. Weekly serum administration prolonged the survival of susceptible mice. Although cellular immunity is required for complete bacterial clearance, the data show that antibodies can play a significant role in the elimination of this obligate intracellular bacterium during active infection and thus challenge the paradigm that humoral responses are unimportant for immunity to such organisms.

APA, Harvard, Vancouver, ISO, and other styles

18

Schmitz-Esser, Stephan, Ilka Haferkamp, Silvia Knab, Thomas Penz, Michelle Ast, Christian Kohl, Michael Wagner, and Matthias Horn. "Lawsonia intracellularis Contains a Gene Encoding a Functional Rickettsia-Like ATP/ADP Translocase for Host Exploitation." Journal of Bacteriology 190, no. 17 (July 7, 2008): 5746–52. http://dx.doi.org/10.1128/jb.00391-08.

Full text

Abstract:

ABSTRACT ATP/ADP translocases are a hallmark of obligate intracellular pathogens related to chlamydiae and rickettsiae. These proteins catalyze the highly specific exchange of bacterial ADP against host ATP and thus allow bacteria to exploit their hosts' energy pool, a process also referred to as energy parasitism. The genome sequence of the obligate intracellular pathogen Lawsonia intracellularis (Deltaproteobacteria), responsible for one of the most economically important diseases in the swine industry worldwide, revealed the presence of a putative ATP/ADP translocase most similar to known ATP/ADP translocases of chlamydiae and rickettsiae (around 47% amino acid sequence identity). The gene coding for the putative ATP/ADP translocase of L. intracellularis (L. intracellularis nucleotide transporter 1 [NTT1 Li ]) was cloned and expressed in the heterologous host Escherichia coli. The transport properties of NTT1 Li were determined by measuring the uptake of radioactively labeled substrates by E. coli. NTT1 Li transported ATP in a counterexchange mode with ADP in a highly specific manner; the substrate affinities determined were 236.3 (± 36.5) μM for ATP and 275.2 (± 28.1) μM for ADP, identifying this protein as a functional ATP/ADP translocase. NTT1 Li is the first ATP/ADP translocase from a bacterium not related to Chlamydiae or Rickettsiales, showing that energy parasitism by ATP/ADP translocases is more widespread than previously recognized. The occurrence of an ATP/ADP translocase in L. intracellularis is explained by a relatively recent horizontal gene transfer event with rickettsiae as donors.

APA, Harvard, Vancouver, ISO, and other styles

19

Blanc, G., H. Ogata, C. Robert, S. Audic, J. M. Claverie, and D. Raoult. "Lateral gene transfer between obligate intracellular bacteria: Evidence from the Rickettsia massiliae genome." Genome Research 17, no. 11 (November 1, 2007): 1657–64. http://dx.doi.org/10.1101/gr.6742107.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Fan, H., R. C. Brunham, and G. McClarty. "Acquisition and synthesis of folates by obligate intracellular bacteria of the genus Chlamydia." Journal of Clinical Investigation 90, no. 5 (November 1, 1992): 1803–11. http://dx.doi.org/10.1172/jci116055.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Sloan, Daniel B., and Nancy A. Moran. "Endosymbiotic bacteria as a source of carotenoids in whiteflies." Biology Letters 8, no. 6 (September 12, 2012): 986–89. http://dx.doi.org/10.1098/rsbl.2012.0664.

Full text

Abstract:

Although carotenoids serve important biological functions, animals are generally unable to synthesize these pigments and instead obtain them from food. However, many animals, such as sap-feeding insects, may have limited access to carotenoids in their diet, and it was recently shown that aphids have acquired the ability to produce carotenoids by lateral transfer of fungal genes. Whiteflies also contain carotenoids but show no evidence of the fungus-derived genes found in aphids. Because many sap-feeding insects harbour intracellular bacteria, it has long been hypothesized that these endosymbionts could serve as an alternative source of carotenoid biosynthesis. We sequenced the genome of the obligate bacterial endosymbiont Portiera from the whitefly Bemisia tabaci . The genome exhibits typical signatures of obligate endosymbionts in sap-feeding insects, including extensive size reduction (358.2 kb) and enrichment for genes involved in essential amino acid biosynthesis. Unlike other sequenced insect endosymbionts, however, Portiera has bacterial homologues of the fungal carotenoid biosynthesis genes in aphids. Therefore, related lineages of sap-feeding insects appear to have convergently acquired the same functional trait by distinct evolutionary mechanisms—bacterial endosymbiosis versus fungal lateral gene transfer.

APA, Harvard, Vancouver, ISO, and other styles

22

N. Tabrizi, Sepehr. "Diagnosis of Chlamydia trachomatis using self-collected non-invasive specimens ? the Australian experience." Microbiology Australia 28, no. 1 (2007): 12. http://dx.doi.org/10.1071/ma07010.

Full text

Abstract:

Chlamydia trachomatis are small, non-motile, obligate intracellular bacteria that typically infect human eukaryotic columnar epithelial cells. C. trachomatis infections result in a number of diseases of worldwide public health concern, including trachoma, lymphogranuloma venereum (LGV) and urogenital infections. Chlamydia is the most common sexually transmitted bacterial pathogen worldwide and in Australia has exhibited a steady rise in prevalence 1. National notification rates of newly diagnosed chlamydia infections have increased nearly four-fold since 1994 and more than doubled since 1999.

APA, Harvard, Vancouver, ISO, and other styles

23

Kuechler, Stefan Martin, Konrad Dettner, and Siegfried Kehl. "Characterization of an Obligate Intracellular Bacterium in the Midgut Epithelium of the Bulrush Bug Chilacis typhae (Heteroptera, Lygaeidae, Artheneinae)." Applied and Environmental Microbiology 77, no. 9 (March 4, 2011): 2869–76. http://dx.doi.org/10.1128/aem.02983-10.

Full text

Abstract:

ABSTRACTMany members of the suborder Heteroptera have symbiotic bacteria, which are usually found extracellularly in specific sacs or tubular outgrowths of the midgut or intracellularly in mycetomes. In this study, we describe the second molecular characterization of a symbiotic bacterium in a monophagous, seed-sucking stink bug of the family Lygaeidae (sensu stricto).Chilacis typhaepossesses at the end of the first section of the midgut a structure which is composed of circularly arranged, strongly enlarged midgut epithelial cells. It is filled with an intracellular endosymbiont. This “mycetocytic belt” might represent an evolutionarily intermediate stage of the usual symbiotic structures found in stink bugs. Phylogenetic analysis based on the 16S rRNA and thegroELgenes showed that the bacterium belongs to theGammaproteobacteria, and it revealed a phylogenetic relationship with a secondary bacterial endosymbiont ofCimex lectulariusand free-living plant pathogens such asPectobacteriumandDickeya. The distribution and ultrastructure of the rod-shapedChilacisendosymbiont were studied in adults and nymph stages using fluorescencein situhybridization (FISH) and electron microscopy. The detection of symbionts at the anterior poles of developing eggs indicates that endosymbionts are transmitted vertically. A new genus and species name, “CandidatusRohrkolberia cinguli,” is proposed for this newly characterized clade of symbiotic bacteria.

APA, Harvard, Vancouver, ISO, and other styles

24

Ardissone, Silvia, Aurélie Scherler, Trestan Pillonel, Virginie Martin, Carole Kebbi-Beghdadi, and Gilbert Greub. "Transcriptional Landscape of Waddlia chondrophila Aberrant Bodies Induced by Iron Starvation." Microorganisms 8, no. 12 (November 24, 2020): 1848. http://dx.doi.org/10.3390/microorganisms8121848.

Full text

Abstract:

Chronic infections caused by obligate intracellular bacteria belonging to the Chlamydiales order are related to the formation of persistent developmental forms called aberrant bodies (ABs), which undergo DNA replication without cell division. These enlarged bacteria develop and persist upon exposure to different stressful conditions such as β-lactam antibiotics, iron deprivation and interferon-γ. However, the mechanisms behind ABs biogenesis remain uncharted. Using an RNA-sequencing approach, we compared the transcriptional profile of ABs induced by iron starvation to untreated bacteria in the Chlamydia-related species Waddliachondrophila, a potential agent of abortion in ruminants and miscarriage in humans. Consistent with the growth arrest observed following iron depletion, our results indicate a significant reduction in the expression of genes related to energy production, carbohydrate and amino acid metabolism and cell wall/envelope biogenesis, compared to untreated, actively replicating bacteria. Conversely, three putative toxin-antitoxin modules were among the most up-regulated genes upon iron starvation, suggesting that their activation might be involved in growth arrest in adverse conditions, an uncommon feature in obligate intracellular bacteria. Our work represents the first complete transcriptomic profile of a Chlamydia-related species in stressful conditions and sets the grounds for further investigations on the mechanisms underlying chlamydial persistence.

APA, Harvard, Vancouver, ISO, and other styles

25

Rymaszewska, A., and S. Grenda. "Bacteria of the genus Anaplasma – characteristics of Anaplasma and their vectors: a review." Veterinární Medicína 53, No. 11 (December 15, 2008): 573–84. http://dx.doi.org/10.17221/1861-vetmed.

Full text

Abstract:

Over recent years, there has been a growing interest in bacteria from the genus Anaplasma, especially the species A. marginale, A. ovis and A. phagocytophilum. It is connected with the pathogenic activity of these bacteria in farm animals, and also, though to a lesser degree, in humans. Anaplasmosis, a disease caused by various species of anaplasma, is an especially important issue for animal breeders. The main vectors of the Anaplasma bacteria are ticks, common arachnida occurring everywhere in the world, especially the genera Ixodes, Dermacentor, Rhipicephalus and Amblyomma. The genus Anaplasma includes obligate intracellular bacteria, parasitizing in the vacuoles of cells in eukaryotic hosts. A. marginale, A. centrale, A. ovis andA. bovis are obligate intracellular bacteria parasitizing in erythrocytes and monocytes of higher vertebrates, mostly ruminants. A. platys is mainly a pathogen of canines (displaying tropism to thrombocytes) and the species A. phagocytophilum (displaying tropism to granulocytes) is pathogenic to people and domestic animals. In this paper we present characteristics and differentiation of six species of the genus Anaplasma and their vectors in the world.

APA, Harvard, Vancouver, ISO, and other styles

26

Husnik, Filip, Vaclav Hypsa, and Alistair Darby. "Insect—Symbiont Gene Expression in the Midgut Bacteriocytes of a Blood-Sucking Parasite." Genome Biology and Evolution 12, no. 4 (February 18, 2020): 429–42. http://dx.doi.org/10.1093/gbe/evaa032.

Full text

Abstract:

Abstract Animals interact with a diverse array of both beneficial and detrimental microorganisms. In insects, these symbioses in many cases allow feeding on nutritionally unbalanced diets. It is, however, still not clear how are obligate symbioses maintained at the cellular level for up to several hundred million years. Exact mechanisms driving host–symbiont interactions are only understood for a handful of model species and data on blood-feeding hosts with intracellular bacteria are particularly scarce. Here, we analyzed interactions between an obligately blood-sucking parasite of sheep, the louse fly Melophagus ovinus, and its obligate endosymbiont, Arsenophonus melophagi. We assembled a reference transcriptome for the insect host and used dual RNA-Seq with five biological replicates to compare expression in the midgut cells specialized for housing symbiotic bacteria (bacteriocytes) to the rest of the gut (foregut–hindgut). We found strong evidence for the importance of zinc in the system likely caused by symbionts using zinc-dependent proteases when acquiring amino acids, and for different immunity mechanisms controlling the symbionts than in closely related tsetse flies. Our results show that cellular and nutritional interactions between this blood-sucking insect and its symbionts are less intimate than what was previously found in most plant-sap sucking insects. This finding is likely interconnected to several features observed in symbionts in blood-sucking arthropods, particularly their midgut intracellular localization, intracytoplasmic presence, less severe genome reduction, and relatively recent associations caused by frequent evolutionary losses and replacements.

APA, Harvard, Vancouver, ISO, and other styles

27

Korhonen, Juha T., Mirja Puolakkainen, Reetta Häivälä, Tuula Penttilä, Anu Haveri, Eveliina Markkula, and Riitta Lahesmaa. "Flotillin-1 (Reggie-2) Contributes to Chlamydia pneumoniae Growth and Is Associated with Bacterial Inclusion." Infection and Immunity 80, no. 3 (January 3, 2012): 1072–78. http://dx.doi.org/10.1128/iai.05528-11.

Full text

Abstract:

Chlamydiaeare obligate intracellular pathogens replicating only inside the eukaryotic host. Here, we studied the effect of human flotillin-1 protein onChlamydia pneumoniaegrowth in human line (HL) and A549 epithelial cell lines. RNA interference was applied to disrupt flotillin-1-mediated endocytosis. Host-associated bacteria were detected by quantitative PCR, andC. pneumoniaegrowth was evaluated by inclusion counts.C. pneumoniaeattachment to host cells was unaffected, but bacterial intracellular growth was attenuated in the flotillin-1-silenced cells. By using confocal microscopy, we detected flotillin-1 colocalized with the inclusion membrane protein A (IncA) in theC. pneumoniaeinclusion membranes. In addition, flotillin-1 was associated with IncA in detergent-resistant membrane microdomains (DRMs) in biochemical fractioning. These results suggest that flotillin-1 localizes to theC. pneumoniaeinclusion membrane and plays an important role for intracellular growth ofC. pneumoniae.

APA, Harvard, Vancouver, ISO, and other styles

28

Wu, Jinyu, Tonghai Yu, Qiyu Bao, and Fangqing Zhao. "Evidence of Extensive Homologous Recombination in the Core Genome ofRickettsia." Comparative and Functional Genomics 2009 (2009): 1–5. http://dx.doi.org/10.1155/2009/510270.

Full text

Abstract:

The important role of homologous recombination has been extensively demonstrated to be fundamental for genetic variation in bacterial genomes. In contrast to extracellular or facultative intracellular bacteria, obligate intracellular bacteria are considered to be less prone to recombination, especially for their core genomes. InRickettsia, only antigen-related genes were identified to have experienced homologous recombination. In this study, we employed evolutionary genomic approaches to investigate the impact of recombination on the core genome ofRickettsia. Phylogenetic network and phylogenetic compatibility matrix analyses are clearly consistent with the hypothesis that recombination has occurred frequently duringRickettsiaevolution. 28% ofRickettsiacore genes (194 out of 690) are found to present the evidence of recombination under four independent statistical methods. Further functional classification shows that these recombination events occur across all functional categories, with a significant overrepresentation in the cell wall/membrane/envelope biogenesis, which may provide a molecular basis for the parasite adaptation to host immunity. This evolutionary genomic analysis provides insight into the substantial role of recombination in the evolution of the intracellular pathogenic bacteriaRickettsia.

APA, Harvard, Vancouver, ISO, and other styles

29

Willems, H., Cornelie Jäger, and Georg Baljer. "Physical and Genetic Map of the Obligate Intracellular Bacterium Coxiella burnetii." Journal of Bacteriology 180, no. 15 (August 1, 1998): 3816–22. http://dx.doi.org/10.1128/jb.180.15.3816-3822.1998.

Full text

Abstract:

ABSTRACT Pulsed-field gel electrophoresis and PCR techniques have been used to construct a NotI macrorestriction map of the obligate intracellular bacterium Coxiella burnetii Nine Mile. The size of the chromosome has been determined to be 2,103 kb comprising 29NotI restriction fragments. The average resolution is 72.5 kb, or about 3.5% of the genome. Experimental data support the presence of a linear chromosome. Published genes were localized on the physical map by Southern hybridization. One gene, recognized as transposable element, was found to be present in at least nine sites evenly distributed over the whole chromosome. There is only one copy of a 16S rRNA gene. The putative oriC has been located on a 27.5-kb NotI fragment. Gene organization upstream theoriC is almost identical to that of Pseudomonas putida and Bacillus subtilis, whereas gene organization downstream the oriC seems to be unique among bacteria. The physical map will be helpful in investigations of the great heterogeneity in restriction fragment length polymorphism patterns of different isolates and the great variation in genome size. The genetic map will help to determine whether gene order in different isolates is conserved.

APA, Harvard, Vancouver, ISO, and other styles

30

Орлова, Светлана, Svetlana Orlova, Александр Сидорчук, Aleksandr Sidorchuk, Татьяна Гребенникова, and Tat'yana Grebennikova. "Cultivation of mycoplasmas ― a retrospective and prospects." Russian veterinary journal 2018, no. 5 (November 30, 2018): 6–13. http://dx.doi.org/10.32416/article_5d1caf6645a4b1.87344381.

Full text

Abstract:

Isolation and identification of mycoplasmas from different species of domestic animals have recently become increasingly important. This prompted us to carry out research work to simplify the methods of sampling, cultivation, cloning, and storage of mycoplasmas living on the mucous membranes of dogs and cats. However, the unique properties of these bacteria, actually occupying an intermediate position between extracellular and intracellular parasites, often lead to confusion and misunderstanding. Indeed, even highly qualified veterinarians often have the wrong judgment that mycoplasmas are obligate intracellular bacteria similar Chlamydia or Rickettsia. Therefore, before presenting the main results of our studies, we gave a brief description of these unusual bacteria in this small review, with putting a focus on the properties which prevent to effective laboratory diagnostics.

APA, Harvard, Vancouver, ISO, and other styles

31

Binet, Rachel, Anne K. Bowlin, Anthony T. Maurelli, and Roger G. Rank. "Impact of Azithromycin Resistance Mutations on the Virulence and Fitness of Chlamydia caviae in Guinea Pigs." Antimicrobial Agents and Chemotherapy 54, no. 3 (January 11, 2010): 1094–101. http://dx.doi.org/10.1128/aac.01321-09.

Full text

Abstract:

ABSTRACT Azithromycin (AZM) is a major drug used in the treatment and prophylaxis of infections caused by Chlamydia, yet no significant clinical resistance has been reported for these obligate intracellular bacteria. Nevertheless, spontaneous AZM resistance (Azmr) arose in vitro at frequencies ranging from 3 × 10−8 to 8 × 10−10 for clonal isolates of Chlamydia caviae, which is a natural pathogen of guinea pigs. Sequencing of the unique 23S rRNA gene copy in 44 independent Azmr isolates identified single mutations at position A2058 or A2059 (Escherichia coli numbering system). While SP6AZ1 (A2058C) and SP6AZ2 (A2059C) Azmr mutants showed growth defects in cell culture and were less pathogenic in the guinea pig ocular infection model than in the parent SP6, the three isogenic C. caviae isolates grew equally well in the animal. On the other hand, coinoculation of the C. caviae parent strain with one of the Azmr strains was detrimental for the mutant strain. This apparent lack of association between pathology and bacterial load in vivo showed that virulence of the two Azmr mutants of C. caviae was attenuated. While chlamydial growth in vitro reflects the ability of the bacteria to multiply in permissive cells, survival in the host is a balance between cellular multiplication and clearance by the host immune system. The obligate intracellular nature of Chlamydia may therefore limit emergence of resistance in vivo due to the strength of the immune response induced by the wild-type antibiotic-sensitive bacteria at the time of antibiotic treatment.

APA, Harvard, Vancouver, ISO, and other styles

32

Wang, Xiaozhu, Xiao Xiong, Wenqi Cao, Chao Zhang, John H. Werren, and Xu Wang. "Genome Assembly of the A-Group Wolbachia in Nasonia oneida Using Linked-Reads Technology." Genome Biology and Evolution 11, no. 10 (October 1, 2019): 3008–13. http://dx.doi.org/10.1093/gbe/evz223.

Full text

Abstract:

Abstract Wolbachia are obligate intracellular bacteria which commonly infect various nematode and arthropod species. Genome sequences have been generated from arthropod samples following enrichment for the intracellular bacteria, and genomes have also been assembled from arthropod whole-genome sequencing projects. However, these methods remain challenging for infections that occur at low titers in hosts. Here we report the first Wolbachia genome assembled from host sequences using 10× Genomics linked-reads technology. The high read depth attainable by this method allows for recovery of intracellular bacteria that are at low concentrations. Based on the depth differences (714× for the insect and 59× for the bacterium), we assembled the genome of a Wolbachia in the parasitoid jewel wasp species Nasonia oneida. The final draft assembly consists of 1,293, 06 bp in 47 scaffolds with 1,114 coding genes and 97.01% genome completeness assessed by checkM. Comparisons of the five Multi Locus Sequence Typing genes revealed that the sequenced Wolbachia genome is the A1 strain (henceforth wOneA1) previously reported in N. oneida. Pyrosequencing confirms that the wasp strain lacks A2 and B types previously detected in this insect, which were likely lost during laboratory culturing. Assembling bacterial genomes from host genome projects can provide an effective method for sequencing bacterial genomes, even when the infections occur at low density in sampled tissues.

APA, Harvard, Vancouver, ISO, and other styles

33

Ko, Youngho, Ji-Hye Choi, Na-Young Ha, Ik-Sang Kim, Nam-Hyuk Cho, and Myung-Sik Choi. "Active Escape of Orientia tsutsugamushi from Cellular Autophagy." Infection and Immunity 81, no. 2 (December 10, 2012): 552–59. http://dx.doi.org/10.1128/iai.00861-12.

Full text

Abstract:

ABSTRACTOrientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular pathogen. After entry into host cells, the bacterium rapidly escapes from the endosomal pathway and replicates in the cytosol of eukaryotic host cells. Here we show thatO. tsutsugamushiinfection efficiently promotes cellular autophagy, a cell-autonomous defense mechanism of innate immunity. However, most of the internalized bacteria barely colocalized with the induced autophagosomes, even when stimulated with rapamycin, a chemical inducer of autophagy. Treatment of infected cells with tetracycline suppressed bacterial evasion from autophagy and facilitatedO. tsutsugamushitargeting to autophagosomes, suggesting that the intracellular pathogen may be equipped with a bacterial factor or factors that block autophagic recognition. Finally, we also found that chemical modulators of cellular autophagy or genetic knockout of theatg3gene does not significantly affect the intracellular growth ofO. tsutsugamushiin vitro. These results suggest thatO. tsutsugamushihas evolved to block autophagic microbicidal defense by evading autophagic recognition even though it activates the autophagy pathway during the early phase of infection.

APA, Harvard, Vancouver, ISO, and other styles

34

Hess, Sebastian, Andreas Suthaus, and Michael Melkonian. "“Candidatus Finniella” (Rickettsiales, Alphaproteobacteria), Novel Endosymbionts of Viridiraptorid Amoeboflagellates (Cercozoa, Rhizaria)." Applied and Environmental Microbiology 82, no. 2 (November 13, 2015): 659–70. http://dx.doi.org/10.1128/aem.02680-15.

Full text

Abstract:

ABSTRACTTheRickettsiales(Alphaproteobacteria) are obligate intracellular bacteria that colonize a wide range of eukaryotic hosts, including diverse metazoa and protists. Here, we characterize rickettsial endosymbionts discovered in the cytoplasm of the algivorous amoeboflagellatesViridiraptor invadensandOrciraptor agilis(Viridiraptoridae, Cercozoa, Rhizaria), supplying evidence of free-living, phagotrophic members of the Cercozoa serving as hosts forRickettsiales. According to 16S rRNA gene phylogenies, the bacteria represent two closely related but distinct genotypes within a deep-branching rickettsial clade, which contains the genera “CandidatusOdyssella,” “CandidatusParacaedibacter,” and “CandidatusCaptivus.” Using the full-cycle rRNA approach, we detected the novel bacteria in four of nine viridiraptorid strains tested. Furthermore, two specific oligonucleotide probes with a single-nucleotide-difference discriminated both bacterial genotypes by fluorescencein situhybridization (FISH). We establish the candidate species “CandidatusFinniella inopinata” (found inViridiraptor invadens) and “CandidatusFinniella lucida” (found inOrciraptor agilis) for the novel bacteria and propose a new, provisional family ofRickettsiales, “CandidatusParacaedibacteraceae.”

APA, Harvard, Vancouver, ISO, and other styles

35

Douglas, Angela E., and John A. Raven. "Genomes at the interface between bacteria and organelles." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1429 (January 29, 2003): 5–18. http://dx.doi.org/10.1098/rstb.2002.1188.

Full text

Abstract:

The topic of the transition of the genome of a free–living bacterial organism to that of an organelle is addressed by considering three cases. Two of these are relatively clear–cut as involving respectively organisms (cyanobacteria) and organelles (plastids). Cyanobacteria are usually free–living but some are involved in symbioses with a range of eukaryotes in which the cyanobacterial partner contributes photosynthesis, nitrogen fixation, or both of these. In several of these symbioses the cyanobacterium is vertically transmitted, and in a few instances, sufficient unsuccessful attempts have been made to culture the cyanobiont independently for the association to be considered obligate for the cyanobacterium. Plastids clearly had a cyanobacterial ancestor but cannot grow independently of the host eukaryote. Plastid genomes have at most 15% of the number of genes encoded by the cyanobacterium with the smallest number of genes; more genes than are retained in the plastid genome have been transferred to the eukaryote nuclear genome, while the rest of the cyanobacterial genes have been lost. Even the most cyanobacteria–like plastids, for example the ‘cyanelles’ of glaucocystophyte algae, are functionally and genetically very similar to other plastids and give little help in indicating intermediates in the evolution of plastids. The third case considered is the vertically transmitted intracellular bacterial symbionts of insects where the symbiosis is usually obligate for both partners. The number of genes encoded by the genomes of these obligate symbionts is intermediate between that of organelles and that of free–living bacteria, and the genomes of the insect symbionts also show rapid rates of sequence evolution and AT (adenine, thymine) bias. Genetically and functionally, these insect symbionts show considerable similarity to organelles.

APA, Harvard, Vancouver, ISO, and other styles

36

Nicholson, Tracy L., Karen Chiu, and Richard S. Stephens. "Chlamydia trachomatis Lacks an Adaptive Response to Changes in Carbon Source Availability." Infection and Immunity 72, no. 7 (July 2004): 4286–89. http://dx.doi.org/10.1128/iai.72.7.4286-4289.2004.

Full text

Abstract:

ABSTRACT Most bacteria coordinately regulate gene expression as an adaptive response to a variety of environmental changes. One key environmental cue is the carbon source necessary for central metabolism. We used microarray analysis to monitor the global transcriptional response of the obligate intracellular pathogen Chlamydia trachomatis to the presence of glycolytic and gluconeogenic carbon sources. In contrast to free-living bacteria, changing the carbon source from glucose to glutamate or α-ketoglutarate had little effect on the global gene transcription of C. trachomatis.

APA, Harvard, Vancouver, ISO, and other styles

37

Lukic, Ruzica, Bojana Lukovic, Nevena Gajovic, Slava Prljic, and Slobodanka Djukic. "Mechanisms of Intracellular Chlamydiae Survival." Serbian Journal of Experimental and Clinical Research 17, no. 2 (June 1, 2016): 145–52. http://dx.doi.org/10.1515/sjecr-2016-0010.

Full text

Abstract:

AbstractChlamydiae are Gram-negative, non-motile, obligate intracellular, and spherically shaped bacteria with a diameter of 0.2-1.5 μm. Chlamydiae are present in several different morphological forms: the elementary body, the reticular body, and in the last several years, there has been the observation of a third form known as the persistent or atypical form. The intracellular localization of Chlamydia provides a unique replication cycle that occurs inside a membrane-surrounded vacuole in the host cell cytoplasm and is significantly different from the method of multiplication of other microorganisms. Chlamydiae are capable of manipulating different signalling pathways inside the infected cell, thus avoiding the host immune response. This ensures intracellular multiplication, survival, and long-term persistence of Chlamydiae. There are two basic means of achieving this persistence: inhibition of apoptosis and manipulation of NF-κB (nuclear factor kappa B)-mediated signals in the host.

APA, Harvard, Vancouver, ISO, and other styles

38

Stepkowski, T., and A. B. Legocki. "Reduction of bacterial genome size and expansion resulting from obligate intracellular lifestyle and adaptation to soil habitat." Acta Biochimica Polonica 48, no. 2 (June 30, 2001): 367–81. http://dx.doi.org/10.18388/abp.2001_3922.

Full text

Abstract:

Prokaryotic organisms are exposed in the course of evolution to various impacts, resulting often in drastic changes of their genome size. Depending on circumstances, the same lineage may diverge into species having substantially reduced genomes, or such whose genomes have undergone considerable enlargement. Genome reduction is a consequence of obligate intracellular lifestyle rendering numerous genes expendable. Another consequence of intracellular lifestyle is reduction of effective population size and limited possibility of gene acquirement via lateral transfer. This causes a state of relaxed selection resulting in accumulation of mildly deleterious mutations that can not be corrected by recombination with the wild type copy. Thus, gene loss is usually irreversible. Additionally, constant environment of the eukaryotic cell renders that some bacterial genes involved in DNA repair are expandable. The loss of these genes is a probable cause of mutational bias resulting in a high A+T content. While causes of genome reduction are rather indisputable, those resulting in genome expansion seem to be less obvious. Presumably, the genome enlargement is an indirect consequence of adaptation to changing environmental conditions and requires the acquisition and integration of numerous genes. It seems that the need for a great number of capabilities is common among soil bacteria irrespective of their phylogenetic relationship. However, this would not be possible if soil bacteria lacked indigenous abilities to exchange and accumulate genetic information. The latter are considerably facilitated when housekeeping genes are physically separated from adaptive loci which are useful only in certain circumstances.

APA, Harvard, Vancouver, ISO, and other styles

39

Dille, Stephanie, Eva-Maria Kleinschnitz, Collins Waguia Kontchou, Thilo Nölke, and Georg Häcker. "In Contrast to Chlamydia trachomatis, Waddlia chondrophila Grows in Human Cells without Inhibiting Apoptosis, Fragmenting the Golgi Apparatus, or Diverting Post-Golgi Sphingomyelin Transport." Infection and Immunity 83, no. 8 (June 8, 2015): 3268–80. http://dx.doi.org/10.1128/iai.00322-15.

Full text

Abstract:

TheChlamydialesare an order of obligate intracellular bacteria sharing a developmental cycle inside a cytosolic vacuole, with very diverse natural hosts, from amoebae to mammals. The clinically most important species isChlamydia trachomatis. Many uncertainties remain as to howChlamydiaorganizes its intracellular development and replication. The discovery of newChlamydialesspecies from other families permits the comparative analysis of cell-biological events and may indicate events that are common to all or peculiar to some species and more or less tightly linked to “chlamydial” development. We used this approach in the infection of human cells withWaddlia chondrophila, a species from the familyWaddliaceaewhose natural host is uncertain. Compared toC. trachomatis,W. chondrophilahad slightly different growth characteristics, including faster cytotoxicity. The embedding in cytoskeletal structures was not as pronounced as for theC. trachomatisinclusion.C. trachomatisinfection generates proteolytic activity by the proteaseChlamydiaprotease-like activity factor (CPAF), which degrades host substrates upon extraction; these substrates were not cleaved in the case ofW. chondrophila. UnlikeChlamydia,W. chondrophiladid not protect against staurosporine-induced apoptosis.C. trachomatisinfection causes Golgi apparatus fragmentation and redirects post-Golgi sphingomyelin transport to the inclusion; both were absent fromW. chondrophila-infected cells. When host cells were infected with both species, growth of both species was reduced. This study highlights differences between bacterial species that both depend on obligate intracellular replication inside an inclusion. Some features seem principally dispensable for intracellular development ofChlamydialesin vitrobut may be linked to host adaptation ofChlamydiaand the higher virulence ofC. trachomatis.

APA, Harvard, Vancouver, ISO, and other styles

40

Beatty, Wandy L. "Late Endocytic Multivesicular Bodies Intersect the Chlamydial Inclusion in the Absence of CD63." Infection and Immunity 76, no. 7 (April 21, 2008): 2872–81. http://dx.doi.org/10.1128/iai.00129-08.

Full text

Abstract:

ABSTRACT Chlamydiae are obligate intracellular bacterial pathogens that replicate solely within a membrane-bound vacuole termed an inclusion. Within the confines of the inclusion, the replicating bacteria acquire amino acids, nucleotides, and other precursors from the host cell. Trafficking from CD63-positive multivesicular bodies to the inclusion was previously identified as a novel interaction that provided essential precursors for the maintenance of a productive intracellular infection. The present study analyzes the direct delivery of resident protein and lipid constituents of multivesicular bodies to the intracellular chlamydiae. The manipulation of this trafficking pathway with an inhibitor of multivesicular body transport and the delivery of exogenous antibodies altered protein and cholesterol acquisition and delayed the maturation of the chlamydial inclusion. Although inhibitor studies and ultrastructural analyses confirmed a novel interaction between CD63-positive multivesicular bodies and the intracellular chlamydiae, neutralization with small interfering RNAs and anti-CD63 Fab fragments revealed that CD63 itself was not required for this association. These studies confirm CD63 as a constituent in multivesicular body-to-inclusion transport; however, other requisite components of these host cell compartments must control the delivery of key nutrients that are essential to intracellular bacterial development.

APA, Harvard, Vancouver, ISO, and other styles

41

Pannekoek, Yvonne, Giovanna Morelli, Barica Kusecek, Servaas A. Morré, Jacobus M. Ossewaarde, Ankie A. Langerak, and Arie van der Ende. "Multi locus sequence typing of Chlamydiales: clonal groupings within the obligate intracellular bacteria Chlamydia trachomatis." BMC Microbiology 8, no. 1 (2008): 42. http://dx.doi.org/10.1186/1471-2180-8-42.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Estes, Anne M., David J. Hearn, Judith L. Bronstein, and Elizabeth A. Pierson. "The Olive Fly Endosymbiont, “Candidatus Erwinia dacicola,” Switches from an Intracellular Existence to an Extracellular Existence during Host Insect Development." Applied and Environmental Microbiology 75, no. 22 (September 18, 2009): 7097–106. http://dx.doi.org/10.1128/aem.00778-09.

Full text

Abstract:

ABSTRACT As polyphagous, holometabolous insects, tephritid fruit flies (Diptera: Tephritidae) provide a unique habitat for endosymbiotic bacteria, especially those microbes associated with the digestive system. Here we examine the endosymbiont of the olive fly [Bactrocera oleae (Rossi) (Diptera: Tephritidae)], a tephritid of great economic importance. “Candidatus Erwinia dacicola” was found in the digestive systems of all life stages of wild olive flies from the southwestern United States. PCR and microscopy demonstrated that “Ca. Erwinia dacicola” resided intracellularly in the gastric ceca of the larval midgut but extracellularly in the lumen of the foregut and ovipositor diverticulum of adult flies. “Ca. Erwinia dacicola” is one of the few nonpathogenic endosymbionts that transitions between intracellular and extracellular lifestyles during specific stages of the host's life cycle. Another unique feature of the olive fly endosymbiont is that unlike obligate endosymbionts of monophagous insects, “Ca. Erwinia dacicola” has a G+C nucleotide composition similar to those of closely related plant-pathogenic and free-living bacteria. These two characteristics of “Ca. Erwinia dacicola,” the ability to transition between intracellular and extracellular lifestyles and a G+C nucleotide composition similar to those of free-living relatives, may facilitate survival in a changing environment during the development of a polyphagous, holometabolous host. We propose that insect-bacterial symbioses should be classified based on the environment that the host provides to the endosymbiont (the endosymbiont environment).

APA, Harvard, Vancouver, ISO, and other styles

43

Rychlik, Jennifer L., and James B. Russell. "Bacteriocin-Like Activity of Butyrivibrio fibrisolvens JL5 and Its Effect on Other Ruminal Bacteria and Ammonia Production." Applied and Environmental Microbiology 68, no. 3 (March 2002): 1040–46. http://dx.doi.org/10.1128/aem.68.3.1040-1046.2002.

Full text

Abstract:

ABSTRACT When ruminal bacteria from a cow fed hay were serially diluted into an anaerobic medium that had only peptides and amino acids as energy sources, little growth or ammonia production was detected at dilutions greater than 10−6. The 10−8 and 10−9 dilutions contained bacteria that fermented carbohydrates, and some of these bacteria inhibited Clostridium sticklandii SR, an obligate amino acid-fermenting bacterium. Phylogenetic analysis indicated that the most active isolate (JL5) was closely related to Butyrivibrio fibrisolvens B835. Strain JL5 inhibited B. fibrisolvens 49 and a variety of other gram-positive organisms, but it had little effect on most gram-negative ruminal bacteria. Strain JL5 did not produce a bacteriocin-like inhibitory substance (BLIS) until it reached the late log or stationary phase. The JL5 BLIS did not cause the lysis of B. fibrisolvens 49, but the intracellular potassium level, the ATP level, the electrical potential, and the viability decreased rapidly. The JL5 BLIS also caused marked decreases in the viability and cellular potassium level of C. sticklandii SR. The membrane potential and intracellular ATP level also declined. The BLIS was degraded very slowly by pronase E, but it could be precipitated with 60% ammonium sulfate and dialyzed (3,500-Da cutoff). The BLIS could be separated from other peptides by polyacrylamide gel electrophoresis, and C. sticklandii SR overlays indicated that the molecular size of this compound was approximately 3,600 Da. Based on these results, it appeared that the JL5 BLIS was a pore-forming peptide. Because carbohydrate-fermenting ruminal bacteria could inhibit the growth of obligate amino acid-fermenting bacteria, BLIS may play a role in regulating ammonia production in vivo.

APA, Harvard, Vancouver, ISO, and other styles

44

Vivoda, Maja, Ivana Cirkovic, Djordje Aleksic, Lazar Ranin, and Slobodanka Djukic. "Biology and intracellular life of chlamydia." Medical review 64, no. 11-12 (2011): 561–64. http://dx.doi.org/10.2298/mpns1112561v.

Full text

Abstract:

Introduction. Chlamydiae are Gram-negative obligate intracellular bacteria. The developmental cycle of Chlamydiae is specific and different from other bacteria. The elementary body is the infectious form of the organism, responsible for attaching to the target host cell and promoting its entry. The reticulate body is the larger, metabolically active form of the organism, synthesizing deoxyribonucleic acid, ribonucleic acid and proteins. The elementary body and reticulate body represent evolutionary adaptations to extracellular and intracellular environments. Intracellular persistence of Chlamydia. Predisposition of Chlamydia to persist within the host cell has been recognized as a major factor in the pathogenesis of chlamydial disease. The persistence implies a long-term association between chlamydiae and their host cell that may not manifest as clinically recognizable disease. The ability of chlamydia to remain within one morphological state for a long time in response to exogenous factors suggests an innate ability of these organisms to persist intracellulary in a unique developmental form. Chlamydiae induce interferon ? and exhibit growth inhibition in their presence. While the high levels of interferon ? completely restrict the development of chlamydia, its low levels induce the development of morphologically aberrant intracellular forms. The persistent forms contain reduced levels of major outer membrane protein but high levels of chlamydial heat shock protein. Conclusion. Immunopathogenesis of chlamydial infection is one of the main focal points of current research into Chlamydia. Chlamydial infections are highly prevalent, usually asymptomatic and associated with serious sequelae. Screening programmes are the most important in the prevention of a long-term sequele.

APA, Harvard, Vancouver, ISO, and other styles

45

Li, Julia Shu-yi, and Gary M. Winslow. "Survival, Replication, and Antibody Susceptibility of Ehrlichia chaffeensis outside of Host Cells." Infection and Immunity 71, no. 8 (August 2003): 4229–37. http://dx.doi.org/10.1128/iai.71.8.4229-4237.2003.

Full text

Abstract:

ABSTRACT Ehrlichia chaffeensis, an obligate intracellular, tick-transmitted bacterium, is susceptible to antibody-mediated host defense, but the mechanism by which this occurs is not understood. One possible explanation is that antibodies directly access the bacteria in the extracellular environment of the host, perhaps during bacterial intercellular transfer. Accordingly, we investigated whether bacteria could be found outside of host cells during infection. Host cell-free plasma obtained from infected mice was found to contain ehrlichiae, and the host cell-free ehrlichiae readily transferred disease to susceptible SCID recipients. The host cell-free ehrlichiae were found during infection of both immunocompetent BALB/c and immunocompromised BALB/c-scid mice and reached levels as high as 108/ml in plasma during persistent infection in SCID mice. Approximately 10% of the blood-borne bacteria were found outside of host cells. Although it is generally accepted that replication of ehrlichiae occurs only within host cells, the cell-free bacteria were shown to undergo DNA replication and cell division in vitro for 3 to 5 days when incubated at 37°C in plasma. Paradoxically, both infectivity and virulence were lost after 24 h of ex vivo culture. The data indicate that E. chaffeensis is exposed to the extracellular milieu during infection, presumably during intercellular transfer, and reveal that these intracellular bacteria do not require the environment of the host cell for replication. Our findings reveal a possible mechanism by which antibodies can access the intracellular bacteria upon their release into the extracellular milieu and mediate host defense and also have implications for understanding the replication and transmission of this vector-borne pathogen.

APA, Harvard, Vancouver, ISO, and other styles

46

Wixon, Jo. "Reductive Evolution in Bacteria:Buchnerasp.,Rickettsia prowazekiiandMycobacterium leprae." Comparative and Functional Genomics 2, no. 1 (2001): 44–48. http://dx.doi.org/10.1002/cfg.70.

Full text

Abstract:

Obligate intracellular bacteria commonly have much reduced genome sizes compared to their nearest free-living relatives. One reason for this is reductive evolution: the loss of genes rendered non-essential due to the intracellular habitat. This can occur because of the presence of orthologous genes in the host, combined with the ability of the bacteria to import the protein or metabolite products of the host genes. In this article we take a look at three such bacteria whose genomes have been fully sequenced.Buchnerais an endosymbiont of the pea aphid,Acyrthosiphon pisum, the relationship between these two organisms being so essential that neither can reproduce in the absence of the other.Rickettsia prowazekiiis the causative agent of louse-borne typhus in humans andMycobacterium lepraeinfection of humans leads to leprosy. Both of these human pathogens have fastidious growth requirements, which has made them very difficult to study.

APA, Harvard, Vancouver, ISO, and other styles

47

Manzano-Marı́n, Alejandro, Armelle Coeur d’acier, Anne-Laure Clamens, Céline Orvain, Corinne Cruaud, Valérie Barbe, and Emmanuelle Jousselin. "Serial horizontal transfer of vitamin-biosynthetic genes enables the establishment of new nutritional symbionts in aphids’ di-symbiotic systems." ISME Journal 14, no. 1 (October 17, 2019): 259–73. http://dx.doi.org/10.1038/s41396-019-0533-6.

Full text

Abstract:

Abstract Many insects depend on obligate mutualistic bacteria to provide essential nutrients lacking from their diet. Most aphids, whose diet consists of phloem, rely on the bacterial endosymbiont Buchnera aphidicola to supply essential amino acids and B vitamins. However, in some aphid species, provision of these nutrients is partitioned between Buchnera and a younger bacterial partner, whose identity varies across aphid lineages. Little is known about the origin and the evolutionary stability of these di-symbiotic systems. It is also unclear whether the novel symbionts merely compensate for losses in Buchnera or carry new nutritional functions. Using whole-genome endosymbiont sequences of nine Cinara aphids that harbour an Erwinia-related symbiont to complement Buchnera, we show that the Erwinia association arose from a single event of symbiont lifestyle shift, from a free-living to an obligate intracellular one. This event resulted in drastic genome reduction, long-term genome stasis, and co-divergence with aphids. Fluorescence in situ hybridisation reveals that Erwinia inhabits its own bacteriocytes near Buchnera’s. Altogether these results depict a scenario for the establishment of Erwinia as an obligate symbiont that mirrors Buchnera’s. Additionally, we found that the Erwinia vitamin-biosynthetic genes not only compensate for Buchnera’s deficiencies, but also provide a new nutritional function; whose genes have been horizontally acquired from a Sodalis-related bacterium. A subset of these genes have been subsequently transferred to a new Hamiltonella co-obligate symbiont in one specific Cinara lineage. These results show that the establishment and dynamics of multi-partner endosymbioses can be mediated by lateral gene transfers between co-ocurring symbionts.

APA, Harvard, Vancouver, ISO, and other styles

48

Schmitz-Esser, Stephan, Nicole Linka, Astrid Collingro, Cora L. Beier, H. Ekkehard Neuhaus, Michael Wagner, and Matthias Horn. "ATP/ADP Translocases: a Common Feature of Obligate Intracellular Amoebal Symbionts Related to Chlamydiae and Rickettsiae." Journal of Bacteriology 186, no. 3 (February 1, 2004): 683–91. http://dx.doi.org/10.1128/jb.186.3.683-691.2004.

Full text

Abstract:

ABSTRACT ATP/ADP translocases catalyze the highly specific transport of ATP across a membrane in an exchange mode with ADP. Such unique transport proteins are employed by plant plastids and have among the prokaryotes so far only been identified in few obligate intracellular bacteria belonging to the Chlamydiales and the Rickettsiales. In this study, 12 phylogenetically diverse bacterial endosymbionts of free-living amoebae and paramecia were screened for the presence of genes encoding ATP/ADP transport proteins. The occurrence of ATP/ADP translocase genes was found to be restricted to endosymbionts related to rickettsiae and chlamydiae. We showed that the ATP/ADP transport protein of the Parachlamydia-related endosymbiont of Acanthamoeba sp. strain UWE25, a recently identified relative of the important human pathogens Chlamydia trachomatis and Chlamydophila pneumoniae, is functional when expressed in the heterologous host Escherichia coli and demonstrated the presence of transcripts during the chlamydial developmental cycle. These findings indicate that the interaction between Parachlamydia-related endosymbionts and their amoeba hosts concerns energy parasitism similar to the interaction between pathogenic chlamydiae and their human host cells. Phylogenetic analysis of all known ATP/ADP translocases indicated that the genes encoding ATP/ADP translocases originated from a chlamydial ancestor and were, after an ancient gene duplication, transferred horizontally to rickettsiae and plants.

APA, Harvard, Vancouver, ISO, and other styles

49

Corsaro, Daniele, and Gilbert Greub. "Pathogenic Potential of Novel Chlamydiae and Diagnostic Approaches to Infections Due to These Obligate Intracellular Bacteria." Clinical Microbiology Reviews 19, no. 2 (April 2006): 283–97. http://dx.doi.org/10.1128/cmr.19.2.283-297.2006.

Full text

Abstract:

SUMMARY Novel chlamydiae are newly recognized members of the phylum Chlamydiales that are only distantly related to the classic Chlamydiaceae, i.e., Chlamydia and Chlamydophila species. They also exibit an obligate biphasic intracellular life cycle within eukaryote host cells. Some of these new chlamydiae are currently considered potential emerging human and/or animal pathogens. Parachlamydia acanthamoebae and Simkania negevensis are both emerging respiratory human pathogens, Waddlia chondrophila could be a novel abortigenic bovine agent, and Piscichlamydia salmonis has recently been identified as an agent of the gill epitheliocystis in the Atlantic salmon. Fritschea spp. and Rhabdochlamydia spp. seem to be confined to arthropods, but some evidence for human exposure exists. In this review, we first summarize the data supporting a pathogenic potential of the novel chlamydiae for humans and other vertebrates and the interactions that most of these chlamydiae have with free-living amoebae. We then review the diagnostic approaches to infections potentially due to the novel chlamydiae, especially focusing on the currently available PCR-based protocols, mammalian cell culture, the amoebal coculture system, and serology.

APA, Harvard, Vancouver, ISO, and other styles

50

Obradovic, Milan, J. Alex Pasternak, Siew Hon Ng, and Heather L. Wilson. "Use of flow cytometry and PCR analysis to detect 5-carboxyfluoroscein-stained obligate intracellular bacteria Lawsonia intracellularis invasion of McCoy cells." Journal of Microbiological Methods 126 (July 2016): 60–66. http://dx.doi.org/10.1016/j.mimet.2016.04.015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Obligate intracellular bacteria'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles