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Berlin Brandenburg

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  • 11
    Language: English
    In: Journal of Bacteriology, 2012, Vol. 194(10), p.2646
    Description: Escherichia coli K-12 WcaJ and the Caulobacter crescentus HfsE, PssY, and PssZ enzymes are predicted to initiate the synthesis of colanic acid (CA) capsule and holdfast polysaccharide, respectively. These proteins belong to a prokaryotic family of membrane enzymes that catalyze the formation of a phosphoanhydride bond joining a hexose-1-phosphate with undecaprenyl phosphate (Und-P). In this study, in vivo complementation assays of an E. coli K-12 wcaJ mutant demonstrated that WcaJ and PssY can complement CA synthesis. Furthermore, WcaJ can restore holdfast production in C. crescentus. In vitro transferase assays demonstrated that both WcaJ and PssY utilize UDP-glucose but not UDP-galactose. However, in a strain of Salmonella enterica serovar Typhimurium deficient in the WbaP O antigen initiating galactosyltransferase, complementation with WcaJ or PssY resulted in O-antigen production. Gas chromatography-mass spectrometry (GC-MS) analysis of the lipopolysaccharide (LPS) revealed the attachment of both CA and O-antigen molecules to lipid A-core oligosaccharide (OS). Therefore, while UDP-glucose is the preferred substrate of WcaJ and PssY, these enzymes can also utilize UDP-galactose. This unexpected feature of WcaJ and PssY may help to map specific residues responsible for the nucleotide diphosphate specificity of these or similar enzymes. Also, the reconstitution of O-antigen synthesis in Salmonella, CA capsule synthesis in E. coli, and holdfast synthesis provide biological assays of high sensitivity to examine the sugar-1-phosphate transferase specificity of heterologous proteins. ; p. 2646-2657.
    Keywords: Gas-Chromatography-Mass Spectrometry ; Oligosaccharides ; Bioassays ; Glucose 1-Phosphate ; Lipopolysaccharides ; Salmonella Enterica Subsp. Enterica Serovar Typhimurium ; Transferases ; Proteins ; Escherichia Coli K12 ; Antigens ; Caulobacter Crescentus ; Mutants;
    ISSN: 1098-5530
    ISSN: 10985530
    ISSN: 00219193
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  • 12
    Language: English
    In: PLoS ONE, Dec 8, 2014, Vol.9(12)
    Description: Resident bacterial communities (microbiota) and host antimicrobial peptides (AMPs) are both essential components of normal host innate immune responses that limit infection and pathogen induced inflammation. However, their interdependence has not been investigated in the context of urinary tract infection (UTI) susceptibility. Here, we explored the interrelationship between the urinary microbiota and host AMP responses as mechanisms for UTI risk. Using prospectively collected day of surgery (DOS) urine specimens from female pelvic floor surgery participants, we report that the relative abundance and/or frequency of specific urinary microbiota distinguished between participants who did or did not develop a post-operative UTI. Furthermore, UTI risk significantly correlated with both specific urinary microbiota and [beta]-defensin AMP levels. Finally, urinary AMP hydrophobicity and protease activity were greater in participants who developed UTI, and correlated positively with both UTI risk and pelvic floor symptoms. These data demonstrate an interdependency between the urinary microbiota, AMP responses and symptoms, and identify a potential mechanism for UTI risk. Assessment of bacterial microbiota and host innate immune AMP responses in parallel may identify increased risk of UTI in certain populations.
    Keywords: Peptides – Health Aspects ; Proteases – Health Aspects ; Urinary Tract Infections – Risk Factors ; Urinary Tract Infections – Health Aspects ; Microbiota (Symbiotic Organisms) – Health Aspects
    ISSN: 1932-6203
    Source: Cengage Learning, Inc.
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  • 13
    Language: English
    In: Journal of bacteriology, 01 August 2016, Vol.198(15), pp.2131-9
    Description: Intracellular bacterial pathogens in the family Chlamydiaceae are causes of human blindness, sexually transmitted disease, and pneumonia. Genetic dissection of the mechanisms of chlamydial pathogenicity has been hindered by multiple limitations, including the inability to inactivate genes that would prevent the production of elementary bodies. Many genes are also Chlamydia-specific genes, and chlamydial genomes have undergone extensive reductive evolution, so functions often cannot be inferred from homologs in other organisms. Conditional mutants have been used to study essential genes of many microorganisms, so we screened a library of 4,184 ethyl methanesulfonate-mutagenized Chlamydia trachomatis isolates for temperature-sensitive (TS) mutants that developed normally at physiological temperature (37°C) but not at nonphysiological temperatures. Heat-sensitive TS mutants were identified at a high frequency, while cold-sensitive mutants were less common. Twelve TS mutants were mapped using a novel markerless recombination approach, PCR, and genome sequencing. TS alleles of genes that play essential roles in other bacteria and chlamydia-specific open reading frames (ORFs) of unknown function were identified. Temperature-shift assays determined that phenotypes of the mutants manifested at distinct points in the developmental cycle. Genome sequencing of a larger population of TS mutants also revealed that the screen had not reached saturation. In summary, we describe the first approach for studying essential chlamydial genes and broadly applicable strategies for genetic mapping in Chlamydia spp. and mutants that both define checkpoints and provide insights into the biology of the chlamydial developmental cycle. Study of the pathogenesis of Chlamydia spp. has historically been hampered by a lack of genetic tools. Although there has been recent progress in chlamydial genetics, the existing approaches have limitations for the study of the genes that mediate growth of these organisms in cell culture. We used a genetic screen to identify conditional Chlamydia mutants and then mapped these alleles using a broadly applicable recombination strategy. Phenotypes of the mutants provide fundamental insights into unexplored areas of chlamydial pathogenesis and intracellular biology. Finally, the reagents and approaches we describe are powerful resources for the investigation of these organisms.
    Keywords: Recombination, Genetic ; Temperature ; Chlamydia Trachomatis -- Physiology
    ISSN: 00219193
    E-ISSN: 1098-5530
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  • 14
    Language: English
    In: Gastroenterology, May 2018, Vol.154(6), pp.S-857-S-857
    Keywords: Medicine
    ISSN: 0016-5085
    E-ISSN: 1528-0012
    Source: ScienceDirect Journals (Elsevier)
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  • 15
    Language: English
    In: Gastroenterology, April 2015, Vol.148(4), pp.S-637-S-638
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/S0016-5085(15)32147-8 Byline: Kalyan Ray Parashette, Vishal kumar Sarsani, Evelyn Toh, Emily C. Hon, Sarath Chandra Janga, David Nelson, Sandeep K. Gupta
    Keywords: Medicine
    ISSN: 0016-5085
    E-ISSN: 1528-0012
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  • 16
    Language: English
    In: Emerging infectious diseases, February 2017, Vol.23(2), pp.336-339
    Description: At a clinic in Indianapolis, Indiana, USA, we observed an increase in Neisseria gonorrhoeae-negative men with suspected gonococcal urethritis who had urethral cultures positive for N. meningitidis. We describe genomes of 2 of these N. meningitidis sequence type 11 complex urethritis isolates. Clinical evidence suggests these isolates may represent an emerging urethrotropic clade.
    Keywords: Neisseria ; Neisseria Gonorrhoeae ; Neisseria Meningitidis ; Bacteria ; Genome ; Meningitis ; Sexually Transmitted Disease ; Sexually Transmitted Infections ; Urethra ; Urethritis ; Neisseria Meningitidis -- Classification ; Urethritis -- Epidemiology
    ISSN: 10806040
    E-ISSN: 1080-6059
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  • 17
    Language: English
    In: Infection and immunity, July 2018, Vol.86(7)
    Description: Some members of the genus , including the human pathogen , infect multiple tissues, including the genital and gastrointestinal (GI) tracts. However, it is unknown if bacterial targeting to these sites is mediated by multifunctional or distinct chlamydial factors. We previously showed that disruption of individual large clostridial toxin homologs encoded within the plasticity zone were not critical for murine genital tract infection. Here, we assessed whether cytotoxin genes contribute to GI tropism. Infectivity and shedding of wild-type (WT) and three mutants containing nonsense mutations in different cytotoxin genes, , , and , were compared in mouse genital and GI infection models. One mutant, which had a nonsense mutation in , was highly attenuated for GI infection and had a GI 50% infectious dose (ID) that was 1,000 times greater than that of the WT. GI inoculation with this mutant failed to elicit anti-chlamydial antibodies or to protect against subsequent genital tract infection. Genome sequencing of the mutant revealed additional chromosomal mutations, and phenotyping of additional mutants suggested that the GI attenuation might be linked to a nonsense mutation in The molecular mechanism underlying this dramatic difference in tissue-tropic virulence is not fully understood. However, isolation of these mutants demonstrates that distinct chlamydial chromosomal factors mediate chlamydial tissue tropism and provides a basis for vaccine initiatives to isolate chlamydia strains that are attenuated for genital infection but retain the ability to colonize the GI tract and elicit protective immune responses.
    Keywords: Chlamydia ; Gastrointestinal Infection ; Genital Tract Immunity ; Intracellular Bacteria ; Intracellular Pathogen ; Sexually Transmitted Diseases ; Tropism ; Chlamydia Infections -- Etiology ; Chlamydia Muridarum -- Pathogenicity ; Chromosomes -- Physiology ; Gastrointestinal Diseases -- Etiology ; Reproductive Tract Infections -- Etiology
    ISSN: 00199567
    E-ISSN: 1098-5522
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  • 18
    In: Critical Care Medicine, 2017, Vol.45(6), pp.e543-e551
    Description: OBJECTIVES:: Characterization of urinary bacterial microbiome and antimicrobial peptides after burn injury to identify potential mechanisms leading to urinary tract infections and associated morbidities in burn patients. DESIGN:: Retrospective cohort study using human urine from control and burn subjects. SETTING:: University research laboratory. PATIENTS:: Burn patients. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Urine samples from catheterized burn patients were collected hourly for up to 40 hours. Control urine was collected from “healthy” volunteers. The urinary bacterial microbiome and antimicrobial peptide levels and activity were compared with patient outcomes. We observed a significant increase in urinary microbial diversity in burn patients versus controls, which positively correlated with a larger percent burn and with the development of urinary tract infection and sepsis postadmission, regardless of age or gender. Urinary psoriasin and β-defensin antimicrobial peptide levels were significantly reduced in burn patients at 1 and 40 hours postadmission. We observed a shift in antimicrobial peptide hydrophobicity and activity between control and burn patients when urinary fractions were tested against Escherichia coli and Enterococcus faecalis urinary tract infection isolates. Furthermore, the antimicrobial peptide activity in burn patients was more effective against E. coli than E. faecalis. Urinary tract infection–positive burn patients with altered urinary antimicrobial peptide activity developed either an E. faecalis or Pseudomonas aeruginosa urinary tract infection, suggesting a role for urinary antimicrobial peptides in susceptibility to select uropathogens. CONCLUSIONS:: Our data reveal potential links for urinary tract infection development and several morbidities in burn patients through alterations in the urinary microbiome and antimicrobial peptides. Overall, this study supports the concept that early assessment of urinary antimicrobial peptide responses and the bacterial microbiome may be used to predict susceptibility to urinary tract infections and sepsis in burn patients.
    Keywords: Medicine;
    ISSN: 0090-3493
    E-ISSN: 15300293
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  • 19
    Language: English
    In: Journal of bacteriology, March 2004, Vol.186(5), pp.1438-47
    Description: Caulobacter crescentus has a dimorphic life cycle composed of a motile stage and a sessile stage. In the sessile stage, C. crescentus is often found tightly attached to a surface through its adhesive holdfast. In this study, we examined the contribution of growth and external structures to the attachment of C. crescentus to abiotic surfaces. We show that the holdfast is essential but not sufficient for optimal attachment. Rather, adhesion in C. crescentus is a complex developmental process. We found that the attachment of C. crescentus to surfaces is cell cycle regulated and that growth or energy or both are essential for this process. The initial stage of attachment occurs in swarmer cells and is facilitated by flagellar motility and pili. Our results suggest that strong attachment is mediated by the synthesis of a holdfast as the swarmer cell differentiates into a stalked cell.
    Keywords: Bacterial Adhesion ; Gene Expression Regulation, Bacterial ; Caulobacter Crescentus -- Growth & Development
    ISSN: 0021-9193
    E-ISSN: 10985530
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  • 20
    In: The ISME Journal, 2015
    Description: Vector-borne microbes are subject to the ecological constraints of two distinct microenvironments: that in the arthropod vector and that in the blood of its vertebrate host. Because the structure of bacterial communities in these two microenvironments may substantially affect the abundance of vector-borne microbes, it is important to understand the relationship between bacterial communities in both microenvironments and the determinants that shape them. We used pyrosequencing analyses to compare the structure of bacterial communities in Synosternus cleopatrae fleas and in the blood of their Gerbillus andersoni hosts. We also monitored the interindividual and seasonal variability in these bacterial communities by sampling the same individual wild rodents during the spring and again during the summer. We show that the bacterial communities in each sample type (blood, female flea or male flea) had a similar phylotype composition among host individuals, but exhibited seasonal variability that was not directly associated with host characteristics. The structure of bacterial communities in male fleas and in the blood of their rodent hosts was remarkably similar and was dominated by flea-borne Bartonella and Mycoplasma phylotypes. A lower abundance of flea-borne bacteria and the presence of Wolbachia phylotypes distinguished bacterial communities in female fleas from those in male fleas and in rodent blood. These results suggest that the overall abundance of a certain vector-borne microbe is more likely to be determined by the abundance of endosymbiotic bacteria in the vector, abundance of other vector-borne microbes co-occurring in the vector and in the host blood and by seasonal changes, than by host characteristics.
    Keywords: Biology;
    ISSN: 1751-7362
    E-ISSN: 17517370
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