WorldWideScience

Sample records for bacteroides

  1. Molybdate transport by Bradyrhizobium japonicum bacteroids.

    OpenAIRE

    Maier, R J; Graham, L.

    1988-01-01

    Bacteroid suspensions of Bradyrhizobium japonicum USDA 136 isolated from soybeans grown in Mo-deficient conditions were able to transport molybdate at a nearly constant rate for up to 1 min. The apparent Km for molybdate was 0.1 microM, and the Vmax was about 5 pmol/min per mg (dry weight) of bacteroid. Supplementation of bacteroid suspensions with oxidizable carbon sources did not markedly increase molybdate uptake rates. Anaerobically isolated bacteroids accumulated twice as much Mo in 1 h ...

  2. Species differentiation of Bacteroides dorei from Bacteroides vulgatus and Bacteroides ovatus from Bacteroides xylanisolvens - Back to basics

    DEFF Research Database (Denmark)

    Micha Pedersen, Rune; Marmolin, Ea Sofie; Justesen, Ulrik S

    2013-01-01

    We present the results from 16S sequencing and phenotypic tests for differentiation of Bacteroides dorei from Bacteroides vulgatus and Bacteroides ovatus from Bacteroides xylanisolvens, which was not possible with MALDI-TOF MS. Testing with β-glucosidase could differentiate B. dorei from B. vulga....... vulgatus and a negative catalase reaction could identify B. xylanisolvens....

  3. Plasmidos R en especies de "bacteroides"

    OpenAIRE

    Jiménez Díaz, Rufino

    1982-01-01

    Se han aislado 60 estirpes de bacteroides del grupo fragilis de muestras clínicas procedentes del hospital Universitario de Sevilla que se clasificaron mediante pruebas bioquímicas y cromatografía liquido gas. Se ha estudiado su patr&oac ute;n de resistencia a antibióticos fundamentalmente del grupo b-lactámicos y su correlación con la producción de b-cactamasa. Se estudia la localización de los genes implicados en ambos caracteres; de los experimentos realizados puede deducirse que dichos g...

  4. Viability of Rhizobium bacteroids isolated from soybean nodule protoplasts.

    Science.gov (United States)

    Gresshoff, P M; Rolfe, B G

    1978-01-01

    Bacteriods isolated from protoplasts taken from Rhizobium japonicum induced root nodule of Glycine max L. showed complete viability when plated onto a conventional rhizobial growth medium supplemented with 0.2 M Mannitol. The same medium but without extra mannitol resulted in the absence of colony formation. The protoplast isolation method eliminated the possibility of contaminant bacteria from infection threads to be scored. The redifferentiated bacteroid clones have the same genetical characteristics as the orginal inoculum strain. This and other recent findings of bacteroid viability are discussed in the light of the existing belief that bacteroids are non-viable.

  5. [The first metronidazole-resistant Bacteroides species isolated at Marmara University Hospital: Bacteroides thetaiotaomicron].

    Science.gov (United States)

    Toprak Ülger, Nurver; Sayın, Elvan; Soyad, Ad; Dane, Faysal; Söyletir, Güner

    2013-10-01

    Bacteroides species, the predominant constituents of the human intestinal microbiota can cause serious intraabdominal and postoperative wound infections and bacteremia. Moreover, these bacteria are more resistant to antimicrobial agents than the other anaerobes. The limited number of the antimicrobials, such as carbapenems, beta-lactam/beta-lactamase inhibitors and nitroimidazoles are highly effective in eliminating Bacteroides. However, a few metronidazole-resistant isolates have been reported from several countries recently. The nim genes (nim A-G) are suggested to be responsible for the majority of the metronidazole resistance. Here, we describe a metronidazole-resistant Bacteroides thetaiotaomicron isolated from a blood culture. A gram-negative obligate anaerobic rod was isolated from the postoperative 5th day blood culture of a 62-year-old male patient with adenocarcinoma of the pancreas head. The strain was identified as B.thetaiotaomicron by using a combination of conventional tests and commercially available biochemical kits. Antimicrobial susceptibility testing was performed by agar dilution method. The resistance genes were investigated by means of PCR using specific primer pairs for nim gene. The purified PCR product was sequenced and analyzed by comparison of the consensus sequences with GenBank sequences. The MIC for metronidazole was 16 mg/L. Although the strain was intermediate according the CLSI criteria, it was resistant (> 4 mg/L) according to EUCAST criteria. The isolate was nim gene positive, and nucleotide sequencing of the PCR product shared 100% similarity with nimE gene (emb |AM042593.1 |). On the other hand the isolate was susceptible to carbapenems and sulbactam-ampicillin. Following administration of ampicillin-sulbactam, the patient's fever disappeared after 24 hours. The clinical condition improved considerably and he was discharged at day 8. The patient was followed up at the medical oncology clinic; however he died due to disease

  6. Demonstration of bacteroides capsules by light microscopy and ultrastructural cytochemistry.

    Science.gov (United States)

    Strohm, H; Payne, C M; Ryan, K J

    1983-05-01

    Forty-six anaerobic gram-negative bacilli, including 26 members of the Bacteroides fragilis group (BFG), were examined for capsules by the India ink technic. Thirty-five were encapsulated, including all the BFG strains. As a follow-up, seven of these isolates and two previously studied reference strains (B. fragilis ATCC 23745 and Bacteroides vulgatus ATCC 8482) were examined for capsules by ultrastructural cytochemistry. Using the periodic acid thiocarbohydrazide silver proteinate (PATCSP) method of Thiéry, all the BFG examined were encapsulated. In addition to the reference strains, this included one strain of B. fragilis and four of Bacteroides thetaiotaomicron. One non-BFG strain showed no capsular material. Differences between these results and those reported previously with the ruthenium red technic may reflect species differences in the chemical composition of Bacteroides capsules.

  7. Bacteremia with Bacteroides pyogenes after a cat bite

    DEFF Research Database (Denmark)

    Madsen, Ida Ringsborg; Justesen, Ulrik Stenz

    2011-01-01

    Animal bite wounds are often infected with bacteria from the animal's oral flora. We report what we believe to be the first case of bacteremia with Bacteroides pyogenes resulting from an infected cat bite.......Animal bite wounds are often infected with bacteria from the animal's oral flora. We report what we believe to be the first case of bacteremia with Bacteroides pyogenes resulting from an infected cat bite....

  8. Bacteroides gingivalis and Bacteroides intermedius recognize different sites on human fibrinogen

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, M.S.; Allen, R.D.; Bounelis, P.; Switalski, L.M.; Hook, M. (Univ. of Alabama, Birmingham (USA))

    1990-02-01

    Bacteroides (Porphyromonas) gingivalis and Bacteroides (Porphyromonas) intermedius have been implicated in the etiology of human periodontal diseases. These organisms are able to bind and degrade human fibrinogen, and these interactions may play a role in the pathogenesis of periodontal disease. In attempts to map the bacterial binding sites along the fibrinogen molecule, we have found that strains of B. gingivalis and B. intermedius, respectively, recognize spatially distant and distinct sites on the fibrinogen molecule. Isolated reduced and alkylated alpha-, beta-, and gamma-fibrinogen chains inhibited binding of 125I-fibrinogen to both Bacteroides species in a concentration-dependent manner. Plasmin fragments D and to some extent fragment E, however, produced a concentration-dependent inhibition of 125I-fibrinogen binding to B. intermedius strains but did not affect binding of 125I-fibrinogen to B. gingivalis strains. Radiolabeled fibrinogen chains and fragments were compared with 125I-fibrinogen with respect to specificity and reversibility of binding to bacteria. According to these criteria, gamma chain most closely resembled the native fibrinogen molecule in behavior toward B. gingivalis strains and fragments D most closely resembled fibrinogen in behavior toward B. intermedius strains. The ability of anti-human fibrinogen immunoglobulin G (IgG) to inhibit binding of 125I-fibrinogen to B. intermedius strains was greatly reduced by absorbing the IgG with fragments D. Absorbing the IgG with fragments D had no effect on the ability of the antibody to inhibit binding of 125I-fibrinogen to B. gingivalis strains. A purified staphylococcal fibrinogen-binding protein blocked binding of 125I-fibrinogen to B. intermedius strains but not to B. gingivalis strains.

  9. [Selected properties of Bacteroides fragilis enterotoxigenic strains].

    Science.gov (United States)

    Rokosz, A; Meisel-Mikołajczyk, F

    1995-01-01

    Seven B. fragilis strains were examined. One strain was reference, non-enterotoxigenic, representing serotype E2 according to Beerens et al. (1971). Six strains produced enterotoxin (ETBF). Four of them were isolated from human feces and two of them from swine feces. All strains were investigated morphologically, biochemically (ATB Expression, France) and by means of direct immunofluorescence (Bacteroides--IF test, Poland). Their resistance to chemotherapeutics was tested (ATB Expression, France). The MIC values of clindamycin and metronidazole were determined using E test strips (AB Biodisk, Sweden). Each strain formed capsules. The percentage of encapsulated cells was high (80-100%). Some strains produced thick capsules. Biochemical patterns were similar and typical for B. fragilis rods. One enterotoxigenic strain produced gelatinase and three ETBF strains fermented trehalose. All strains reacted in direct immunofluorescence exclusively with conjugate against serotype E of BFG. Thus, each strain showed antigenic pattern E. Drug susceptibility of all strains was similar. One enterotoxigenic strain was resistant to clindamycin. All strains were susceptible to metronidazole. These studies indicate that on the basis of morphological, biochemical and serological features (IF), enterotoxigenic B. fragilis strains cannot be distinguished from the nonenterotoxigenic one. Also, the correlation between toxigenicity and drug sensitivity of the examined strains is not observed.

  10. Chromosomal DNA probes for the identification of Bacteroides tectum and Bacteroides fragilis from the oral cavity of cats.

    Science.gov (United States)

    Love, D N; Bailey, G D

    1993-01-01

    A dot-blot hybridisation assay using high molecular weight DNA as whole chromosomal probes was used to differentiate Bacteroides tectum from Bacteroides fragilis. 32P-labelled probes were compared with digoxigenin (DIG)-labelled probes. The whole chromosomal probes were specific--differentiating B. tectum from B. fragilis and both from a variety of other species (including other members of the genera Bacteroides, Fusobacterium, Eubacterium, and Prevotella) found in normal and abnormal mouths of cats and horses. However, even at very high stringencies, B. tectum homology groups I, II and III were not distinguishable from one another using either 32P-labelled or DIG-labelled probes. Thus, DIG-labelled whole chromosome probes directed against cellular DNA released directly onto nitrocellulose membranes is considered a useful method for diagnostic veterinary laboratories wishing to identify B. tectum and distinguish it from B. fragilis and other oral anaerobic flora of cats.

  11. Organic Acid Metabolism by Isolated Rhizobium japonicum Bacteroids

    Science.gov (United States)

    Stovall, Iris; Cole, Michael

    1978-01-01

    Rhizobium japonicum bacteroids isolated from soybean (Glycine max L.) nodules oxidized 14C-labeled succinate, pyruvate, and acetate in a manner consistent with operation of the tricarboxylic acid cycle and a partial glyoxylate cycle. Substrate carbon was incorporated into all major cellular components (cell wall + membrane, nucleic acids, and protein). PMID:16660386

  12. Detection of Bacteroides fragilis endotoxin in amniotic fluid by counterimmunoelectrophoresis

    NARCIS (Netherlands)

    I. Beckmann (Ilse); K. de Graaff (K.); F. Meisel-Mikolajczyk; H.C.S. Wallenburg (Henk)

    1994-01-01

    textabstractThe ability of counter immunoelectrophoresis (CIE) to detectBacteroides fragilis endotoxin in amniotic fluid in small concentrations was evaluated. A method was developed which, in combination with ultrafiltration, permits detection ofB. fragilis endotoxin in amniotic fluid in a concentr

  13. Characteristics of bacteroids in indeterminate nodules of the leguminous tree Leucaena glauca.

    Science.gov (United States)

    Ishihara, Hironobu; Koriyama, Hiroki; Osawa, Atsushi; Zehirov, Grigor; Yamaura, Masatoshi; Kucho, Ken-ichi; Abe, Mikiko; Higashi, Shiro; Kondorosi, Eva; Mergaert, Peter; Uchiumi, Toshiki

    2011-01-01

    Rhizobia establish symbiosis with legumes. Bacteroids in indeterminate nodules of Inverted Repeat Lacking Clade (IRLC) legumes undergo terminal differentiation caused by Nodule-specific Cysteine-Rich peptides (NCRs). Microscopic observations of bacteroids and the detection of NCRs in indeterminate nodules of the non-IRLC legume Leucaena glauca were performed. A portion of the bacteroids showed moderate cell elongation, loss of membrane integrity, and multiple nucleoids. The symbiosome contained multiple bacteroids and NCR-like peptides were not detectable. These results indicate that bacteroid differentiation in L. glauca is different from that in IRLC legumes although both hosts form indeterminate nodules.

  14. Identification of feces by detection of Bacteroides genes.

    Science.gov (United States)

    Nakanishi, Hiroaki; Shojo, Hideki; Ohmori, Takeshi; Hara, Masaaki; Takada, Aya; Adachi, Noboru; Saito, Kazuyuki

    2013-01-01

    In forensic science, the identification of feces is very important in a variety of crime investigations. However, no sensitive and simple fecal identification method using molecular biological techniques has been reported. Here, we focused on the fecal bacteria, Bacteroides uniformis, Bacteroides vulgatus and Bacteroides thetaiotaomicron, and developed a novel fecal identification method by detection of the gene sequences specific to these bacteria in various body (feces, blood, saliva, semen, urine, vaginal fluids and skin surfaces) and forensic (anal adhesions) specimens. Bacterial gene detection was performed by real-time PCR using a minor groove binding probe to amplify the RNA polymerase β-subunit gene of B. uniformis and B. vulgatus, and the α-1-6 mannanase gene of B. thetaiotaomicron. At least one of these bacteria was detected in the feces of 20 donors; the proportions of B. uniformis, B. vulgatus and B. thetaiotaomicron were 95, 85 and 60%, respectively. Bacteroides vulgatus was also detected in one of six vaginal fluid samples, but B. thetaiotaomicron and B. uniformis were not detected in body samples other than feces. Further, we applied this method to forensic specimens from 18 donors. Eighteen anal adhesions also contained at least one of three bacteria; B. uniformis, B. vulgatus and B. thetaiotaomicron were detected in 89, 78 and 56%, respectively, of the specimens. Thus, these bacteria were present at a high frequency in the fecal and forensic specimens, while either B. uniformis or B. vulgatus was detected in all samples. Therefore, B. uniformis and B. vulgatus represent more appropriate target species than B. thetaiotaomicron for the identification of fecal material. If B. vulgatus and/or B. uniformis are detected, it is likely that the sample contains feces. Taken together, our results suggest that the use of molecular biological techniques will aid the detection of feces in forensic practice, although it is possible that the samples contained

  15. Production of a fecal mutagen by Bacteroides spp.

    OpenAIRE

    Van Tassel, R L; MacDonald, D K; Wilkins, T D

    1982-01-01

    Forty species of anaerobes were screened for the ability to produce an ether-extractable mutagen which is present in the feces of 15 to 20% of individuals in populations at high risk for colon cancer. This mutagen can be produced in vitro by incubating the feces of these individuals anaerobically or by supplementing anaerobic broths with methanol extracts of the feces and incubating them with a dilute fecal inoculum. Of the anaerobes screened, strains of five species of Bacteroides (B. thetai...

  16. Early intestinal Bacteroides fragilis colonisation and development of asthma

    Directory of Open Access Journals (Sweden)

    Goossens Herman

    2008-09-01

    Full Text Available Abstract Background The 'hygiene hypothesis' suggests that early exposure to microbes can be protective against atopic disease. The intestinal microbial flora could operate as an important postnatal regulator of the Th1/Th2 balance. The aim of the study was to investigate the association between early intestinal colonisation and the development of asthma in the first 3 years of life. Methods In a prospective birth cohort, 117 children were classified according to the Asthma Predictive Index. A positive index included wheezing during the first three years of life combined with eczema in the child in the first years of life or with a parental history of asthma. A faecal sample was taken at the age of 3 weeks and cultured on selective media. Results Asthma Predictive Index was positive in 26/117 (22% of the children. The prevalence of colonisation with Bacteroides fragilis was higher at 3 weeks in index+ compared to index- children (64% vs. 34% p Bacteroides fragilis and Total Anaerobes counts at 3 weeks were significantly higher in children with a positive index as compared with those without. After adjusting for confounders a positive association was found between Bacteroides fragilis colonisation and Asthma Predictive Index (odds ratio: 4,4; confidence interval: 1,7 – 11,8. Conclusion Bacteroides fragilis colonisation at age 3 weeks is an early indicator of possible asthma later in life. This study could provide the means for more accurate targeting of treatment and prevention and thus more effective and better controlled modulation of the microbial milieu.

  17. Bacteriophages infecting Bacteroides as a marker for microbial source tracking.

    Science.gov (United States)

    Jofre, Joan; Blanch, Anicet R; Lucena, Francisco; Muniesa, Maite

    2014-05-15

    Bacteriophages infecting certain strains of Bacteroides are amid the numerous procedures proposed for tracking the source of faecal pollution. These bacteriophages fulfil reasonably well most of the requirements identified as appropriate for a suitable marker of faecal sources. Thus, different host strains are available that detect bacteriophages preferably in water contaminated with faecal wastes corresponding to different animal species. For phages found preferably in human faecal wastes, which are the ones that have been more extensively studied, the amounts of phages found in waters contaminated with human fecal samples is reasonably high; these amounts are invariable through the time; their resistance to natural and anthropogenic stressors is comparable to that of other relatively resistant indicator of faecal pollution such us coliphages; the abundance ratios of somatic coliphages and bacteriophages infecting Bacteroides thetaiotaomicron GA17 are unvarying in recent and aged contamination; and standardised detection methods exist. These methods are easy, cost effective and provide data susceptible of numerical analysis. In contrast, there are some uncertainties regarding their geographical stability, and consequently suitable hosts need to be isolated for different geographical areas. However, a feasible method has been described to isolate suitable hosts in a given geographical area. In summary, phages infecting Bacteroides are a marker of faecal sources that in our opinion merits being included in the "toolbox" for microbial source tracking. However, further research is still needed in order to make clear some uncertainties regarding some of their characteristics and behaviour, to compare their suitability to the one of emerging methods such us targeting Bacteroidetes by qPCR assays; or settling molecular methods for their determination.

  18. Metronidazole and spiramycin therapy of mixed Bacteroides spp. and Neisseria gonorrhoeae infection in mice.

    Science.gov (United States)

    Brook, I

    1989-01-01

    The in vitro and in vivo activity of metronidazole and spiramycin, used singly or in combination, was tested in the eradication of infection caused by Bacteroides spp. and Neisseria gonorrhoeae alone or in combination. The in vitro tests consisted of determinations of the minimal inhibitory concentrations (MIC), carried out with or without the addition of a constant amount of the other antimicrobials. The MIC of both Bacteroides bivius and Bacteroides fragilis for metronidazole were significantly reduced by the addition of spiramycin (from 0.5 to 0.125 micrograms/ml). The in vivo tests were carried out in mice and consisted of measurements of the effects of the antimicrobial agents on the bacterial contents of abscesses induced by subcutaneous injection of bacterial suspension. Synergism between metronidazole and spiramycin was noted against Bacteroides spp. in abscesses caused by either Bacteroides spp. alone, or in combination with N. gonorrhoeae. Furthermore, an additional reduction in the number of N gonorrhoeae was noted in mixed infection with Bacteroides that was treated with metronidazole alone. This study demonstrates the in vitro and in vivo efficacy of the combination of metronidazole and spiramycin in the treatment of infections caused by either Bacteroides spp. alone or in combination with N. gonorrhoeae.

  19. Susceptibility of Bacteroides nodosus to various antimicrobial agents.

    Science.gov (United States)

    Gradin, J L; Schmitz, J A

    1983-08-15

    The susceptibility of 18 strains of Bacteroides nodosus to 21 antimicrobial agents was tested in vitro. Penicillin was the most effective antibiotic tested. Other antibiotics tested, in order of relative efficacy, were cefamandole, clindamycin, tetracycline, chloramphenicol, erythromycin, sodium cefoxitin, tylosin tartrate, nitrofurazone, tinidazole, and dihydrostreptomycin sulfate. Tests of solutions of 4 antibiotics in 70% ethanol indicated that ethanol served primarily as a diluent and did not contribute substantially to the curative effect of such topical medications on foot rot lesions in sheep. Of the chemicals commonly used in foot baths for treatment of ovine foot rot, copper sulfate was most effective, followed by zinc sulfate, then formalin. Several commercial disinfectants and iodine were quite effective against B nodosus, whereas 5.25% sodium hypochlorite and 70% ethanol alone were relatively ineffective.

  20. Persistence of Bacteroides ovatus under simulated sunlight irradiation

    KAUST Repository

    Dong, Shengkun

    2014-07-04

    Background: Bacteroides ovatus, a member of the genus Bacteroides, is considered for use in molecular-based methods as a general fecal indicator. However, knowledge on its fate and persistence after a fecal contamination event remains limited. In this study, the persistence of B. ovatus was evaluated under simulated sunlight exposure and in conditions similar to freshwater and seawater. By combining propidium monoazide (PMA) treatment and quantitative polymerase chain reaction (qPCR) detection, the decay rates of B. ovatus were determined in the presence and absence of exogenous photosensitizers and in salinity up to 39.5 parts per thousand at 27°C. Results: UVB was found to be important for B. ovatus decay, averaging a 4 log10 of decay over 6 h of exposure without the presence of extracellular photosensitizers. The addition of NaNO2, an exogenous sensitizer producing hydroxyl radicals, did not significantly change the decay rate of B. ovatus in both low and high salinity water, while the exogenous sensitizer algae organic matter (AOM) slowed down the decay of B. ovatus in low salinity water. At seawater salinity, the decay rate of B. ovatus was slower than that in low salinity water, except when both NaNO2 and AOM were present. Conclusion: The results of laboratory experiments suggest that if B. ovatus is released into either freshwater or seawater environment in the evening, 50% of it may be intact by the next morning; if it is released at noon, only 50% may be intact after a mere 5 min of full spectrum irradiation on a clear day. This study provides a mechanistic understanding to some of the important environmental relevant factors that influenced the inactivation kinetics of B. ovatus in the presence of sunlight irradiation, and would facilitate the use of B. ovatus to indicate the occurrence of fecal contamination.

  1. In Vitro Kinetic Analysis of Oligofructose Consumption by Bacteroides and Bifidobacterium spp. Indicates Different Degradation Mechanisms

    OpenAIRE

    Van der Meulen, Roel; Makras, Lefteris; Verbrugghe, Kristof; Adriany, Tom; De Vuyst, Luc

    2006-01-01

    The growth of pure cultures of Bacteroides thetaiotaomicron LMG 11262 and Bacteroides fragilis LMG 10263 on fructose and oligofructose was examined and compared to that of Bifidobacterium longum BB536 through in vitro laboratory fermentations. Gas chromatography (GC) analysis was used to determine the different fractions of oligofructose and their degradation during the fermentation process. Both B. thetaiotaomicron LMG 11262 and B. fragilis LMG 10263 were able to grow on oligofructose as fas...

  2. Pyruvate Is Synthesized by Two Pathways in Pea Bacteroids with Different Efficiencies for Nitrogen Fixation▿

    OpenAIRE

    Mulley, Geraldine; Lopez-Gomez, Miguel; Zhang, Ye; Terpolilli, Jason; Prell, Jurgen; Finan, Turlough; Poole, Philip

    2010-01-01

    Nitrogen fixation in legume bacteroids is energized by the metabolism of dicarboxylic acids, which requires their oxidation to both oxaloacetate and pyruvate. In alfalfa bacteroids, production of pyruvate requires NAD+ malic enzyme (Dme) but not NADP+ malic enzyme (Tme). However, we show that Rhizobium leguminosarum has two pathways for pyruvate formation from dicarboxylates catalyzed by Dme and by the combined activities of phosphoenolpyruvate (PEP) carboxykinase (PckA) and pyruvate kinase (...

  3. Molecular Investigations of Bacteroides as Microbial Source Tracking Tools in Southeast Louisiana Watersheds

    Science.gov (United States)

    Schulz, C. J.; Childers, G. W.; Engel, A. S.

    2006-12-01

    Microbial Source Tracking (MST) is a developing field that is gaining increased attention. MST refers to a host of techniques that discriminates among the origins of fecal material found in natural waters from different sources (e.g. human, livestock, and wildlife) by using microbial indicator species with specificity to only certain host organisms. The development of species-specific molecular markers would allow for better evaluation of public health risks and tracking of nutrient sources impacting a watershed. Although several MST methods have been reported with varying levels of success, few offer general applicability for natural waters due to spatial and temporal constraints associated with these methods. One group of molecular MST markers that show promise for broad environmental applications are molecular 16S rDNA probes for Bacteroides. This method is based on 16S rDNA detection directly from environmental samples without the need for a preliminary cultivation step. In this study we have expanded previous sampling efforts to compile a database of over 1000 partial 16S rRNA Bacteroides genes retrieved from the fecal material of 15 different host species (human, cat, dog, pig, kangaroo). To characterize survival of Bacteroides outside of the host, survival time of the Bacteroides marker was compared to that of E.coli under varying natural environmental conditions (temperature and salinity). Bacteroides displayed a survival curve with shouldering and tailing similar to that of E.coli, but log reduction times differed with treatment. In summary, MST marker stability was identified within host species and the overall Bacteroides community structure correlated to host diet, suggesting that detection of a Bacteroides community could confidently identify fecal contamination point sources. Natural water samples from southeast Louisiana were collected for MST including the Tangipahoa River watershed where the source of fecal contamination has been hotly debated. The

  4. Bacteroides species from the oral cavity and oral-associated diseases of cats.

    Science.gov (United States)

    Love, D N; Johnson, J L; Moore, L V

    1989-03-01

    One hundred and sixty-seven strains of Bacteroides were isolated from 71 subcutaneous fight-wound abscesses of cats, 21 cases of feline pyothorax, normal gingival margins from 10 cats and 6 cases of feline gingivitis. Bacteroides species constituted (as a proportion of all anaerobic isolates examined) 44.5% from subcutaneous abscesses, 33.7% from pyothoraxes, 37.5% from normal gingiva and 27.7% from diseased gingiva. Bacteroides tectum comprised 43.7% or 73 of 167 strains, followed by the black- or brown-pigmented asaccharolytic feline species of B. gingivalis, B. salivosus and Group B, comprising 32.3% or 54 of 167 strains. B. heparinolyticus (some 10% or 17 of 167 strains) was the next most common species described. The remainder consisted of two strains of B. fragilis and 21 unspeciated strains. Bacteroides tectum was frequently isolated from subcutaneous abscesses (43.7%) and pyothoraxes (46.6%), and it constituted some 33% of anaerobic isolated from normal gingiva. Bacteroides heparinolyticus was more commonly encountered in purulent lesions (abscesses and pyothoraxes) than in the oral cavity.

  5. Novel Bacteroides host strains for detection of human- and animal-specific bacteriophages in water.

    Science.gov (United States)

    Wicki, Melanie; Auckenthaler, Adrian; Felleisen, Richard; Tanner, Marcel; Baumgartner, Andreas

    2011-03-01

    Bacteriophages active against specific Bacteroides host strains were shown to be suitable for detection of human faecal pollution. However, the practical application of this finding is limited because some specific host strains were restricted to certain geographic regions. In this study, novel Bacteroides host strains were isolated that discriminate human and animal faecal pollution in Switzerland. Two strains specific for bacteriophages present in human faecal contamination and three strains specific for bacteriophages indicating animal faecal contamination were evaluated. Bacteriophages infecting human strains were exclusively found in human wastewater, whereas animal strains detected bacteriophages only in animal waste. The newly isolated host strains could be used to determine the source of surface and spring water faecal contamination in field situations. Applying the newly isolated host Bacteroides thetaiotaomicron ARABA 84 for detection of bacteriophages allowed the detection of human faecal contamination in spring water.

  6. Complete genome sequence of Bacteroides salanitronis type strain (BL78T)

    Energy Technology Data Exchange (ETDEWEB)

    Gronow, Sabine [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Held, Brittany [Los Alamos National Laboratory (LANL); Lucas, Susan [Joint Genome Institute, Walnut Creek, California; Lapidus, Alla L. [Joint Genome Institute, Walnut Creek, California; Glavina Del Rio, Tijana [Joint Genome Institute, Walnut Creek, California; Nolan, Matt [Joint Genome Institute, Walnut Creek, California; Tice, Hope [Joint Genome Institute, Walnut Creek, California; Deshpande, Shweta [Joint Genome Institute, Walnut Creek, California; Cheng, Jan-Fang [Joint Genome Institute, Walnut Creek, California; Pitluck, Sam [Joint Genome Institute, Walnut Creek, California; Liolios, Konstantinos [Joint Genome Institute, Walnut Creek, California; Pagani, Ioanna [Joint Genome Institute, Walnut Creek, California; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Chen, Amy [Joint Genome Institute, Walnut Creek, California; Palaniappan, Krishna [Joint Genome Institute, Walnut Creek, California; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Chang, Yun-Juan [ORNL; Jeffries, Cynthia [Oak Ridge National Laboratory (ORNL); Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Detter, J. Chris [Joint Genome Institute, Walnut Creek, California; Woyke, Tanja [Joint Genome Institute, Walnut Creek, California; Bristow, James [Joint Genome Institute, Walnut Creek, California; Markowitz, Victor [Joint Genome Institute, Walnut Creek, California; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [Joint Genome Institute, Walnut Creek, California; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Eisen, Jonathan [Joint Genome Institute, Walnut Creek, California

    2011-01-01

    Bacteroides salanitronis Lan et al. 2006 is a species of the genus Bacteroides, which belongs to the family Bacteroidaceae. The species is of interest because it was isolated from the gut of a chicken and the growing awareness that the anaerobic microflora of the cecum is of benefit for the host and may impact poultry farming. The 4,308,663 bp long genome consists of a 4.24 Mbp chromosome and three plasmids (6 kbp, 19 kbp, 40 kbp) containing 3,737 protein-coding and 101 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  7. Growth inhibitory effects of endotoxins from Bacteroides gingivalis and intermedius on human gingival fibroblasts in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Layman, D.L.; Diedrich, D.L.

    1987-06-01

    Purified endotoxin or lipopolysaccharide from Bacteroides gingivalis and Bacteroides intermedius caused a similar dose-dependent inhibition of growth of cultured human gingival fibroblasts as determined by /sup 3/H-thymidine incorporation and direct cell count. Approximately 200 micrograms/ml endotoxin caused a 50% reduction in /sup 3/H-thymidine uptake of logarithmically growing cells. Inhibition of growth was similar in cultures of fibroblasts derived from either healthy or diseased human gingiva. When examining the change in cell number with time of exposure in culture, the rate of proliferation was significantly suppressed during the logarithmic phase of growth. However, the cells recovered so that the rate of proliferation, although reduced, was sufficient to produce a cell density similar to the control cells with prolonged culture. The endotoxins were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The profiles of the Bacteroides endotoxins were different. B. gingivalis endotoxin showed a wide range of distinct bands indicating a heterogeneous distribution of molecular species. Endotoxin from B. intermedius exhibited a few discrete low molecular weight bands, but the majority of the lipopolysaccharides electrophoresed as a diffuse band of high molecular weight material. The apparent heterogeneity of the two Bacteroides endotoxins and the similarity in growth inhibitory capacity suggest that growth inhibitory effects of these substances cannot be attributed to any polysaccharide species of endotoxin.

  8. In vitro kinetic analysis of oligofructose consumption by Bacteroides and Bifidobacterium spp. indicates different degradation mechanisms.

    Science.gov (United States)

    Van der Meulen, Roel; Makras, Lefteris; Verbrugghe, Kristof; Adriany, Tom; De Vuyst, Luc

    2006-02-01

    The growth of pure cultures of Bacteroides thetaiotaomicron LMG 11262 and Bacteroides fragilis LMG 10263 on fructose and oligofructose was examined and compared to that of Bifidobacterium longum BB536 through in vitro laboratory fermentations. Gas chromatography (GC) analysis was used to determine the different fractions of oligofructose and their degradation during the fermentation process. Both B. thetaiotaomicron LMG 11262 and B. fragilis LMG 10263 were able to grow on oligofructose as fast as on fructose, succinic acid being the major metabolite produced by both strains. B. longum BB536 grew slower on oligofructose than on fructose. Acetic acid and lactic acid were the main metabolites produced when fructose was used as the sole energy source. Increased amounts of formic acid and ethanol were produced when oligofructose was used as an energy source at the cost of lactic acid. Detailed kinetic analysis revealed a preferential metabolism of the short oligofructose fractions (e.g., F2 and F3) for B. longum BB536. After depletion of the short fractions, the larger oligofructose fractions (e.g., F4, GF4, F5, GF5, and F6) were metabolized, too. Both Bacteroides strains did not display such a preferential metabolism and degraded all oligofructose fractions simultaneously, transiently increasing the fructose concentration in the medium. This suggests a different mechanism for oligofructose breakdown between the strain of Bifidobacterium and both strains of Bacteroides, which helps to explain the bifidogenic nature of inulin-type fructans.

  9. Extensive Mobilome-Driven Genome Diversification in Mouse Gut-Associated Bacteroides vulgatus mpk.

    Science.gov (United States)

    Lange, Anna; Beier, Sina; Steimle, Alex; Autenrieth, Ingo B; Huson, Daniel H; Frick, Julia-Stefanie

    2016-01-01

    Like many other Bacteroides species, Bacteroides vulgatus strain mpk, a mouse fecal isolate which was shown to promote intestinal homeostasis, utilizes a variety of mobile elements for genome evolution. Based on sequences collected by Pacific Biosciences SMRT sequencing technology, we discuss the challenges of assembling and studying a bacterial genome of high plasticity. Additionally, we conducted comparative genomics comparing this commensal strain with the B. vulgatus type strain ATCC 8482 as well as multiple other Bacteroides and Parabacteroides strains to reveal the most important differences and identify the unique features of B. vulgatus mpk. The genome of B. vulgatus mpk harbors a large and diverse set of mobile element proteins compared with other sequenced Bacteroides strains. We found evidence of a number of different horizontal gene transfer events and a genome landscape that has been extensively altered by different mobilization events. A CRISPR/Cas system could be identified that provides a possible mechanism for preventing the integration of invading external DNA. We propose that the high genome plasticity and the introduced genome instabilities of B. vulgatus mpk arising from the various mobilization events might play an important role not only in its adaptation to the challenging intestinal environment in general, but also in its ability to interact with the gut microbiota.

  10. Neuraminidase-enhanced attachment of Bacteroides intermedius to human erythrocytes and buccal epithelial cells.

    OpenAIRE

    Okuda, K; Ono, M.; Kato, T.

    1989-01-01

    Bacteroides intermedius strains strongly agglutinated only neuraminidase-treated erythrocytes. The neuraminidase-dependent hemagglutinating activity of B. intermedius was abolished by heating or treating with protease. The adherence of these microorganisms to human buccal epithelial cells was enhanced by neuraminidase pretreatment of the cells (P less than 0.01).

  11. Genome sequence of the Bacteroides fragilis phage ATCC 51477-B1

    Science.gov (United States)

    Hawkins, Shawn A; Layton, Alice C; Ripp, Steven; Williams, Dan; Sayler, Gary S

    2008-01-01

    The genome of a fecal pollution indicator phage, Bacteroides fragilis ATCC 51477-B1, was sequenced and consisted of 44,929 bases with a G+C content of 38.7%. Forty-six putative open reading frames were identified and genes were organized into functional clusters for host specificity, lysis, replication and regulation, and packaging and structural proteins. PMID:18710568

  12. Multidrug-Resistant Bacteroides fragilis Bacteremia in a US Resident: An Emerging Challenge

    Directory of Open Access Journals (Sweden)

    Cristian Merchan

    2016-01-01

    Full Text Available We describe a case of Bacteroides fragilis bacteremia associated with paraspinal and psoas abscesses in the United States. Resistance to b-lactam/b-lactamase inhibitors, carbapenems, and metronidazole was encountered despite having a recent travel history to India as the only possible risk factor for multidrug resistance. Microbiological cure was achieved with linezolid, moxifloxacin, and cefoxitin.

  13. Energy supply for dinitrogen fixation by Azotobacter vinelandii and by bacteroids of Rhizobium leguminosarum

    NARCIS (Netherlands)

    Laane, N.C.M.

    1980-01-01

    The central issue of this thesis is how obligate aerobes, such as Rhizobium leguminosarum bacteroids and Azotobacter vinelandii, generate and regulate the energy supply (in the form of ATP and reducing equivalents) for nitrogenase.In an effective Rhizobium -legume symbiosis, the actual reduction of

  14. Production of a Mouse Antiserum to Bacteroides fragilis Enterotoxin Using a Recombinant Enterotoxin Precursor

    OpenAIRE

    Sandini, Silvia; d'Abusco, Anna Scotto; La Valle, Roberto; Pantosti, Annalisa

    2001-01-01

    The precursor of the Bacteroides fragilis metalloprotease enterotoxin was cloned and expressed in Escherichia coli, which was not able to process the precursor into the biologically active enterotoxin. Mouse antiserum elicited to the recombinant precursor reacted with the purified enterotoxin and with a crude enterotoxin preparation from an enterotoxigenic strain. The antiserum neutralized the cytotoxic activity of the enterotoxin in HT-29 cells.

  15. Lower Level of Bacteroides in the Gut Microbiota Is Associated with Inflammatory Bowel Disease: A Meta-Analysis

    Science.gov (United States)

    Zhou, Yingting

    2016-01-01

    Background and Aims. Multiple studies have reported associations between inflammatory bowel disease (IBD) and the flora disequilibrium of Bacteroides. We performed a meta-analysis of the available data to provide a more precise estimate of the association between Bacteroides level in the gut and IBD. Methods. We searched PubMed/MEDLINE, EMBASE, Cochrane Library, Wiley Library, BIOSIS previews, Web of Science, CNKI, and ScienceDirect databases for published literature on IBD and gut microbiota from 1990 to 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). We compared the level of Bacteroides in IBD patients with that in a control group without IBD, different types of IBD patients, and IBD patients with active phase and in remission. Results. We identified 63 articles, 9 of which contained sufficient data for evaluation. The mean level of Bacteroides was significantly lower in Crohn's disease (CD) and ulcerative colitis (UC) patients in active phase than in normal controls. The level of Bacteroides in remission CD and UC patients was much lower than patients in the control group. Bacteroides level was even lower in patients with CD and UC in active phase than in remission. Conclusions. This analysis suggests that lower levels of Bacteroides are associated with IBD, especially in active phase. PMID:27999802

  16. Lower Level of Bacteroides in the Gut Microbiota Is Associated with Inflammatory Bowel Disease: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Yingting Zhou

    2016-01-01

    Full Text Available Background and Aims. Multiple studies have reported associations between inflammatory bowel disease (IBD and the flora disequilibrium of Bacteroides. We performed a meta-analysis of the available data to provide a more precise estimate of the association between Bacteroides level in the gut and IBD. Methods. We searched PubMed/MEDLINE, EMBASE, Cochrane Library, Wiley Library, BIOSIS previews, Web of Science, CNKI, and ScienceDirect databases for published literature on IBD and gut microbiota from 1990 to 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS. We compared the level of Bacteroides in IBD patients with that in a control group without IBD, different types of IBD patients, and IBD patients with active phase and in remission. Results. We identified 63 articles, 9 of which contained sufficient data for evaluation. The mean level of Bacteroides was significantly lower in Crohn’s disease (CD and ulcerative colitis (UC patients in active phase than in normal controls. The level of Bacteroides in remission CD and UC patients was much lower than patients in the control group. Bacteroides level was even lower in patients with CD and UC in active phase than in remission. Conclusions. This analysis suggests that lower levels of Bacteroides are associated with IBD, especially in active phase.

  17. Pyruvate is synthesized by two pathways in pea bacteroids with different efficiencies for nitrogen fixation.

    Science.gov (United States)

    Mulley, Geraldine; Lopez-Gomez, Miguel; Zhang, Ye; Terpolilli, Jason; Prell, Jurgen; Finan, Turlough; Poole, Philip

    2010-10-01

    Nitrogen fixation in legume bacteroids is energized by the metabolism of dicarboxylic acids, which requires their oxidation to both oxaloacetate and pyruvate. In alfalfa bacteroids, production of pyruvate requires NAD+ malic enzyme (Dme) but not NADP+ malic enzyme (Tme). However, we show that Rhizobium leguminosarum has two pathways for pyruvate formation from dicarboxylates catalyzed by Dme and by the combined activities of phosphoenolpyruvate (PEP) carboxykinase (PckA) and pyruvate kinase (PykA). Both pathways enable N2 fixation, but the PckA/PykA pathway supports N2 fixation at only 60% of that for Dme. Double mutants of dme and pckA/pykA did not fix N2. Furthermore, dme pykA double mutants did not grow on dicarboxylates, showing that they are the only pathways for the production of pyruvate from dicarboxylates normally expressed. PckA is not expressed in alfalfa bacteroids, resulting in an obligate requirement for Dme for pyruvate formation and N2 fixation. When PckA was expressed from a constitutive nptII promoter in alfalfa dme bacteroids, acetylene was reduced at 30% of the wild-type rate, although this level was insufficient to prevent nitrogen starvation. Dme has N-terminal, malic enzyme (Me), and C-terminal phosphotransacetylase (Pta) domains. Deleting the Pta domain increased the peak acetylene reduction rate in 4-week-old pea plants to 140 to 150% of the wild-type rate, and this was accompanied by increased nodule mass. Plants infected with Pta deletion mutants did not have increased dry weight, demonstrating that there is not a sustained change in nitrogen fixation throughout growth. This indicates a complex relationship between pyruvate synthesis in bacteroids, nitrogen fixation, and plant growth.

  18. Effect of clavulanic acid on the activities of ten beta-lactam agents against members of the Bacteroides fragilis group.

    Science.gov (United States)

    Lamothe, F; Auger, F; Lacroix, J M

    1984-01-01

    Clavulanic acid reduced the MICs of amoxicillin, carbencillin , cefamandole, cefotaxime, ceftazidime, ceftizoxime, cephalothin, and penicillin G, but not of cefoxitin or moxalactam, against 77 isolates of the Bacteroides fragilis group, all rapidly beta-lactamase positive by the nitrocefin slide test. It had no effect on the susceptibilities of eight Bacteroides distasonis strains that were slowly beta-lactamase positive (18 h of incubation). PMID:6732233

  19. Multidrug-resistant Bacteroides fragilis group on the rise in Europe?

    DEFF Research Database (Denmark)

    Hartmeyer, G N; Sóki, J; Nagy, E;

    2012-01-01

    We report a case of multidrug-resistance (MDR) in a strain of Bacteroides fragilis from a blood culture and abdominal fluid in a Danish patient. The patient had not been travelling for several years and had not received antibiotics prior to the present case. We also summarize the cases that have...... been reported to date of MDR B. fragilis group in Europe. As far as we know, a case like this with MDR B. fragilis has not been described in Scandinavia before....

  20. Genome sequence of the Bacteroides fragilis phage ATCC 51477-B1

    Directory of Open Access Journals (Sweden)

    Hawkins Shawn A

    2008-08-01

    Full Text Available Abstract The genome of a fecal pollution indicator phage, Bacteroides fragilis ATCC 51477-B1, was sequenced and consisted of 44,929 bases with a G+C content of 38.7%. Forty-six putative open reading frames were identified and genes were organized into functional clusters for host specificity, lysis, replication and regulation, and packaging and structural proteins.

  1. Analysis of proteins associated with growth of Bacteroides ovatus on the branched galactomannan guar gum.

    OpenAIRE

    Valentine, P J; Salyers, A A

    1992-01-01

    Bacteroides ovatus, a gram-negative obligate anaerobe from the human colon, can ferment the branched galactomannan guar gum. Previously, three enzymes involved in guar gum breakdown were characterized. The expression of these enzymes appeared to be regulated; i.e., specific activities were higher in extracts from bacteria grown on guar gum than in extracts from bacteria grown on the monosaccharide constituents of guar gum, mannose and galactose. In the present study, we used two-dimensional g...

  2. Oxygen-independent killing of Bacteroides fragilis by granule extracts from human polymorphonuclear leukocytes.

    OpenAIRE

    Wetherall, B L; Pruul, H; McDonald, P J

    1984-01-01

    Granule proteins from human neutrophils were prepared by extraction with acetate, and their antibacterial activity against Bacteroides fragilis was determined. Activity was highly dependent on pH; greatest killing occurred at the most acid pH tested (pH 5.0). Optimum activity was observed at physiological ionic strength and low bacterial numbers. Killing was inhibited by incubation temperatures of less than 37 degrees C. Eight times more extract was required to kill 50% of stationary-phase ba...

  3. Augmentation of the in vitro activity of azlocillin against Bacteroides fragilis by clavulanic acid.

    Science.gov (United States)

    Bansal, M B; Chuah, S K; Thadepalli, H

    1984-01-01

    Azlocillin was active against 90% of 154 strains of Bacteroides fragilis at a concentration of 64 micrograms/ml. Twenty-eight strains of B. fragilis with an azlocillin MIC of greater than or equal to 8 micrograms/ml were retested with a combination of azlocillin plus clavulanic acid. Of these strains, 71% showed a 4- to 32-fold decrease in the MIC of azlocillin plus clavulanic acid. PMID:6517552

  4. Bacteroides Fragilis OmpA: Utility as a Live Vaccine Vector for Biodefense Agents

    Science.gov (United States)

    2009-01-01

    same results as the porin alone (data not shown). The supernatants containing the OmpA proteins were subjected to sodium dodecyl sulfate polyacrylamide ...thetaiotaomicron outer membrane protein that is essential for utilization of maltooligosaccharides and starch . J Bacteriol 178, 823-830. Reeves, A. R., Wang, G. R...Salyers, A. A. (1997).Characterization of four outer membrane proteins that play a role in utilization of starch by Bacteroides thetaiotaomicron

  5. Two Sinorhizobium meliloti glutaredoxins regulate iron metabolism and symbiotic bacteroid differentiation.

    Science.gov (United States)

    Benyamina, Sofiane M; Baldacci-Cresp, Fabien; Couturier, Jérémy; Chibani, Kamel; Hopkins, Julie; Bekki, Abdelkader; de Lajudie, Philippe; Rouhier, Nicolas; Jacquot, Jean-Pierre; Alloing, Geneviève; Puppo, Alain; Frendo, Pierre

    2013-03-01

    Legumes interact symbiotically with bacteria of the Rhizobiaceae to form nitrogen-fixing root nodules. We investigated the contribution of the three glutaredoxin (Grx)-encoding genes present in the Sinorhizobium meliloti genome to this symbiosis. SmGRX1 (CGYC active site) and SmGRX3 (CPYG) recombinant proteins displayed deglutathionylation activity in the 2-hydroethyldisulfide assay, whereas SmGRX2 (CGFS) did not. Mutation of SmGRX3 did not affect S. meliloti growth or symbiotic capacities. In contrast, SmGRX1 and SmGRX2 mutations decreased the growth of free-living bacteria and the nitrogen fixation capacity of bacteroids. Mutation of SmGRX1 led to nodule abortion and an absence of bacteroid differentiation, whereas SmGRX2 mutation decreased nodule development without modifying bacteroid development. The higher sensitivity of the Smgrx1 mutant strain as compared with wild-type strain to oxidative stress was associated with larger amounts of glutathionylated proteins. The Smgrx2 mutant strain displayed significantly lower levels of activity than the wild type for two iron-sulfur-containing enzymes, aconitase and succinate dehydrogenase. This lower level of activity could be associated with deregulation of the transcriptional activity of the RirA iron regulator and higher intracellular iron content. Thus, two S. meliloti Grx proteins are essential for symbiotic nitrogen fixation, playing independent roles in bacterial differentiation and the regulation of iron metabolism.

  6. Pigment production by Bacteroides species with reference to sub-classification.

    Science.gov (United States)

    Duerden, B I

    1975-02-01

    All six reference strains of Bacteroides species, 36 laboratory isolates conforming to this group, and individual strains of Escherichia coli, Proteus mirabilis, Salmonella typhimurium and Clostridum welchii produced a dense black pigment, identified as ferrus sulphide, when grown in cooked-meat media containing cystine and ferrous sulphate. This was an indicator effect resulting from the production of H2S by the bacteria in the presence of ferrous ions and was unrelated to the characteristic pigment produced by strains of B. melaninogenicus when grown on blood agar. A pigment was extracted by ultrasonic disintegration of washed cells of three reference strains of B. melanino-genicus grown for 1 week in horse-blood broth and on human-blood agar. It was intracellular or cell-associated, soluble in water and had the spectrophotometric characteristics of a derivative of haemoglobin. No such pigment was extracted from strains of B. fragilis or B. necrophorus by similar procedures. Pigment production is a stable characteristic of those strains of Bacteroides called B. melaninogenicus and it is a significant property in the classification of the Bacteroides group. However, the pigment-producing strains are not a homogenous species, and there were considerable differences between the results of biochemical tests and antibograms obtained with the three strains of B. melaninogenicus.

  7. An electron microscope survey of the surface structures and hydrophobicity of oral and non-oral species of the bacterial genus Bacteroides.

    Science.gov (United States)

    Handley, P S; Tipler, L S

    1986-01-01

    Seventeen strains of Bacteroides representing 10 species were examined by negative staining; the majority were from the mouth but a few non-oral strains were included. Seven species had peritrichously-arranged, non-flagellar appendages which could be divided by morphology and ultrastructure into two subgroups, fibrils and fimbriae. Bacteroides asaccharolyticus strains B536 and B537 and Bacteroides gingivalis strains W50, W83, WPH15 and WPH35 had fimbriae with mean width of 4.4 nm and 0.5 to 6.0 microns long depending on the strain. The fimbrial length within each strain also varied. Fibrils were present on two fresh oral isolates of Bacteroides melaninogenicus, Bacteroides intermedius strains T588 and W09, Bacteroides corporis ATCC 33547, Bacteroides oralis ATCC 33269 and Bacteroides buccae ATCC 33574. Fibrils consistently clumped into bundles of variable thickness and formed a fringe around the cell periphery, ranging from 0.27 to 1.2 microns long depending on the strain. Fibril lengths of each strain were uniform. Fibrils had no measurable width and the clumps tapered towards the free ends. Bacteroides loeschii VPI 9085, Bacteroides pentosaceus strains NP333 and J1 and Bacteroides capillosus 29799 had no detectable surface appendages. Fimbriate strains had a layer outside the outer membrane, with a mean thickness of between 17.8 and 28.6 nm. Both fibrillar and fimbriate strains produced many small membranous vesicles budding from the outer membrane. There were two morphological forms of vesicles, ones with either fimbriae or fibrils (species-dependent) and ones with no attached appendages. Of eleven strains tested for cell-surface hydrophobicity by partitioning between hexadecane and buffer, all but one was non-hydrophobic.

  8. Spinal epidural abscess caused by Bacteroides fragilis group after dilation and curettage for incomplete abortion

    Directory of Open Access Journals (Sweden)

    Masaki Ohyagi

    2012-01-01

    Full Text Available Spinal epidural abscess (SEA is a rare infection complicated in patients who have some risk factors such as injection-drug use, diabetes mellitus, and several illnesses. However, no case of SEA associated with abortion has been reported. Here we report a case of SEA in a 30-year-old woman after dilation and curettage for incomplete abortion. The diagnosis of SEA was done by MRI and pus was drained after the cervical discectomy. Bacteroides fragilis group was cultured from the aspirated pus sample. The patient responded to surgical drainage and antibiotics.

  9. Spinal epidural abscess caused by bacteroides fragilis group after dilation and curettage for incomplete abortion.

    Science.gov (United States)

    Ohyagi, Masaki; Ohkubo, Takuya; Taniyama, Takashi; Tomizawa, Shoji; Okawa, Atsushi; Yokota, Takanori; Mizusawa, Hidehiro

    2012-04-01

    Spinal epidural abscess (SEA) is a rare infection complicated in patients who have some risk factors such as injection-drug use, diabetes mellitus, and several illnesses. However, no case of SEA associated with abortion has been reported. Here we report a case of SEA in a 30-year-old woman after dilation and curettage for incomplete abortion. The diagnosis of SEA was done by MRI and pus was drained after the cervical discectomy. Bacteroides fragilis group was cultured from the aspirated pus sample. The patient responded to surgical drainage and antibiotics.

  10. An assessment of Bacteroides fragilis group organisms as indicators of human faecal pollution.

    Science.gov (United States)

    Allsop, K; Stickler, D J

    1985-01-01

    Membrane filtration techniques were used to enumerate Bacteroides fragilis group (BFG) organisms and Escherichia coli in a variety of natural waters, the influents and effluents from three types of sewage treatment plants and faeces of various animals. The results suggest that BFG organisms die off more rapidly than E. coli in water and that animal faeces are not a significant source of BFG. It is suggested that the ratio of BFG to E. coli in water may be used to indicate the proximity of a source of human faecal contamination.

  11. The enumeration of Bacteroides fragilis group organisms from sewage and natural waters.

    Science.gov (United States)

    Allsop, K; Stickler, D J

    1984-02-01

    A membrane filtration technique has been developed for the enumeration of Bacteroides fragilis group (BFG) organisms from sewage and natural waters. The method uses the agar medium of Wilkins and Chalgren supplemented with gentamicin, penicillin, aesculin and ferric ammonium citrate. Membrane filters with 0.22 micron pores were significantly more efficient than those with 0.45 micron pores in the isolation of BFG. A preliminary incubation period of 4 h at 30 degrees C prior to 44 h at 37 degrees C yielded significantly higher numbers of BFG than direct incubation at 37 degrees C for 48 h.

  12. High quality draft genome sequence of Bacteroides barnesiae type strain BL2(T) (DSM 18169(T)) from chicken caecum.

    Science.gov (United States)

    Sakamoto, Mitsuo; Lapidus, Alla L; Han, James; Trong, Stephan; Haynes, Matthew; Reddy, T B K; Mikhailova, Natalia; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia N; Pukall, Rüdiger; Markowitz, Victor M; Woyke, Tanja; Klenk, Hans-Peter; Kyrpides, Nikos C; Ohkuma, Moriya

    2015-01-01

    Bacteroides barnesiae Lan et al. 2006 is a species of the genus Bacteroides, which belongs to the family Bacteroidaceae. Strain BL2(T) is of interest because it was isolated from the gut of a chicken and the growing awareness that the anaerobic microbiota of the caecum is of benefit for the host and may impact poultry farming. The 3,621,509 bp long genome with its 3,059 protein-coding and 97 RNA genes is a part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.

  13. Different metabolic features of Bacteroides fragilis growing in the presence of glucose and exopolysaccharides of bifidobacteria

    Directory of Open Access Journals (Sweden)

    David eRios-Covian

    2015-08-01

    Full Text Available Bacteroides is among the most abundant microorganism inhabiting the human intestine. They are saccharolytic bacteria able to use dietary or host-derived glycans as energy sources. Some Bacteroides fragilis strains contribute to the maturation of the immune system but it is also an opportunistic pathogen. The intestine is the habitat of most Bifidobacterium species, some of whose strains are considered probiotics. Bifidobacteria can synthesize exopolysaccharides (EPS, which are complex carbohydrates that may be available in the intestinal environment. We studied the metabolism of B. fragilis when an EPS preparation from bifidobacteria was added to the growth medium compared to its behavior with added glucose. 2D-DIGE coupled with the identification by MALDI-TOF/TOF evidenced proteins that were differentially produced when EPS was added. The results were supported by RT-qPCR gene expression analysis. The intracellular and extracellular pattern of certain amino acids, the redox balance and the α-glucosidase activity were differently affected in EPS with respect to glucose. These results allowed us to hypothesize that three general main events, namely the activation of amino acids catabolism, enhancement of the transketolase reaction from the pentose-phosphate cycle, and activation of the succinate-propionate pathway, promote a shift of bacterial metabolism rendering more reducing power and optimizing the

  14. Medicago truncatula root nodule proteome analysis reveals differential plant and bacteroid responses to drought stress.

    Science.gov (United States)

    Larrainzar, Estíbaliz; Wienkoop, Stefanie; Weckwerth, Wolfram; Ladrera, Rubén; Arrese-Igor, Cesar; González, Esther M

    2007-07-01

    Drought is one of the environmental factors most affecting crop production. Under drought, symbiotic nitrogen fixation is one of the physiological processes to first show stress responses in nodulated legumes. This inhibition process involves a number of factors whose interactions are not yet understood. This work aims to further understand changes occurring in nodules under drought stress from a proteomic perspective. Drought was imposed on Medicago truncatula 'Jemalong A17' plants grown in symbiosis with Sinorhizobium meliloti strain 2011. Changes at the protein level were analyzed using a nongel approach based on liquid chromatography coupled to tandem mass spectrometry. Due to the complexity of nodule tissue, the separation of plant and bacteroid fractions in M. truncatula root nodules was first checked with the aim of minimizing cross contamination between the fractions. Second, the protein plant fraction of M. truncatula nodules was profiled, leading to the identification of 377 plant proteins, the largest description of the plant nodule proteome so far. Third, both symbiotic partners were independently analyzed for quantitative differences at the protein level during drought stress. Multivariate data mining allowed for the classification of proteins sets that were involved in drought stress responses. The isolation of the nodule plant and bacteroid protein fractions enabled the independent analysis of the response of both counterparts, gaining further understanding of how each symbiotic member is distinctly affected at the protein level under a water-deficit situation.

  15. Modulation of endogenous indole-3-acetic acid biosynthesis in bacteroids within Medicago sativa nodules.

    Science.gov (United States)

    Bianco, C; Senatore, B; Arbucci, S; Pieraccini, G; Defez, R

    2014-07-01

    To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth.

  16. [Possible role of enterotoxigenic Bacteroides fragilis in the etiology of infectious vaginitis].

    Science.gov (United States)

    Polanco, Nina; Manzi, Lorna; Carmona, Oswaldo

    2012-03-01

    Vaginitis is a common gynecologic disorder. It is due to several causes, some even unknown. Bacteroides fragilis is the most important anaerobe in clinical bacteriology, some strains of this group are notable for being enterotoxigenic and they have been associated with intestinal and extraintestinal syndromes. They have recently been isolated from patients with vaginitis. The purpose of this study was to investigate a possible association of enterotoxigenic B. fragilis with infectious vaginitis. 265 samples of vaginal exudate were processed, 202 from symptomatic patients and 63 healthy women. The identification of the microorganisms was carried out by conventional methods. In 31.2% of symptomatic patients were identified: Gardnerella vaginalis, Mobiluncus, Candida albicans, Mycoplasma hominis, Ureaplasma urealyticum and Streptococcus agalactiae. B. fragilis was identified in 27 symptomatic patients and 5 healthy women. These strains were cultivated in liquid medium and incubated during 48 h at 36 degrees C in anaerobe chambers. Supernatant activity was assayed in HT-29 cells. Eighteen B. fragilis strains isolated from symptomatic patients were enterotoxigenic, because induced alterations in target cell morphology. It was not identified in healthy women (P < 0.05). 77.7% of enterotoxigenic B. fragilis strains were not associated with other specific pathogens. This fact suggests that enterotoxigenic B. fragilis could be a cause for vaginitis. The effect of enterotoxin on E-cadherin of vaginal epithelium could facilitate invasion and its possible pathogenic role in the vagina. This is the first report that associates enterotoxigenic Bacteroides fragilis as a possible cause of infectious vaginitis.

  17. The methylome of the gut microbiome: disparate Dam methylation patterns in intestinal Bacteroides dorei

    Directory of Open Access Journals (Sweden)

    Michael T. Leonard

    2014-07-01

    Full Text Available Despite the large interest in the human microbiome in recent years, there are no reports of bacterial DNA methylation in the microbiome. Here metagenomic sequencing using the Pacific Biosciences platform allowed for rapid identification of bacterial GATC methylation status of a bacterial species in human stool samples. For this work, two stool samples were chosen that were dominated by a single species, Bacteroides dorei. Based on 16S rRNA analysis, this species represented over 45% of the bacteria present in these two samples. The B. dorei genome sequence from these samples was determined and the GATC methylation sites mapped. The Bacteroides dorei genome from one subject lacked any GATC methylation and lacked the DNA adenine methyltransferase genes. In contrast, B. dorei from another subject contained 20,551 methylated GATC sites. Of the 4,970 open reading frames identified in the GATC methylated B. dorei genome, 3,184 genes were methylated as well as 1,735 GATC methylations in intergenic regions. These results suggest that DNA methylation patterns are important to consider in multi-omic analyses of microbiome samples seeking to discover the diversity of bacterial functions and may differ between disease states.

  18. Analysis of Romanian Bacteroides isolates for antibiotic resistance levels and the corresponding antibiotic resistance genes.

    Science.gov (United States)

    Székely, Edit; Eitel, Zsuzsa; Molnár, Szabolcs; Szász, Izabella Éva; Bilca, Doina; Sóki, József

    2015-02-01

    As part of an ESCMID Study Group on Anaerobic Infections (ESGAI) project, a study was conducted to measure the antibiotic susceptibilities and corresponding gene contents of 53 Bacteroides fragilis group strains isolated in Romania. The antibiotic resistance data was comparable with the data found for other East-European countries. Here, no resistant isolate was found for imipenem, metronidazole and tigecycline. An increasing role of the cepA, cfxA and cfiA genes was observed in their corresponding antibiotic resistances. Moreover, no isolate was found that harbored the cfiA gene with a possible activating IS element. Clindamycin resistance was low, similarly to that the rate for the ermF gene. However, we did find some isolates with nimB, ermB, msrSA, linA, satG, tetX, tetM and bexA genes. This study was the first to provide antibiotic resistance data for clinical Bacteroides strains from Romania.

  19. Heterogeneity in resistant fecal Bacteroides fragilis group collected from healthy people.

    Science.gov (United States)

    Narimani, T; Douraghi, M; Owlia, P; Rastegar, A; Esghaei, M; Nasr, B; Talebi, M

    2016-06-01

    Normal nonpathogenic flora would represent a constant lake of resistance genes potentially transferable to human pathogens. To assess the prevalence of resistance genes and genetic variability of Bacteroides fragilis group (BFG) from normal flora, 177 Bacteroides isolates obtained from the fecal samples of healthy individuals. These isolates were subjected to antibiotic susceptibility testing and pulsed field gel electrophoresis (PFGE). The isolates were further tested for the presence of ermF, tetQ and bft genes by PCR. Our results indicated the presence of different clonal strains (1 common type and 57 single types) among the resistant isolates. The resistance rate for the six antibiotics in this study was between 1% and 95%. Most of the isolates (99%) were susceptible to metronidazole. ermF and tetQ were detected in all erythromycin and tetracycline resistant isolates. None of the isolates were carried bft gene. These data suggest dissemination of heterogenic clonal groups in healthy persons and resistance to 5 high commonly used antibiotics.

  20. Adhesion molecule expression stimulated by Bacteroides thetaiotaomicron cell-surface antigens.

    Science.gov (United States)

    Rokosz, A; Meisel-Mikołajczyk, F; Malchar, C; Nowaczyk, M; Górski, A

    1999-01-01

    Bacteroides thetaiotaomicron, a Gram-negative anaerobic rod belonging to the Bacteroides fragilis group (BFG), is involved in many systemic and local, most frequently suppurative infections in man. The cell envelope of these rods is composed of two carbohydrate-containing antigens: lipopolysaccharide (LPS) and capsular polysaccharide (CPS). Adhesion molecules ICAM-1, VCAM-1 and E-selectin (ELAM-1) are induced on the endothelial cells by mediators of inflammation. The aim of this study was to assay the ability of B. thetaiotaomicron surface antigens to induce adhesion molecule expression on the endothelial cells. The influence of LPS and CPS on the expression of adhesion molecules on HMEC-1 cell line was examined in an ELISA test. ELISA was performed with monoclonal mouse anti-human: ICAM-1, VCAM-1 and E-selectin antibodies of the IgG class. B. thetaiotaomicron lipopolysaccharides revealed the ability to induce ICAM-1, VCAM-1 and E-selectin expression on the endothelial cells. Their activities were similar, but lower than the activity of Eschericha coli LPS. ICAM-1 was the most stimulated adhesion molecule. The strongest activation by LPS was achieved at the concentrations of 10.0 and 1.0 micrograms/ml. The ability of capsular polysaccharide to induce the expression of adhesion molecules was considerably weaker.

  1. Evaluation of Bacteroides fragilis GB-124 bacteriophages as novel human-associated faecal indicators in the United States

    Science.gov (United States)

    Phages infecting human-associated Bacteroides fragilis (GB-124 phages) have been employed in the European Union (EU) to identify human fecal pollution, but their utility for U.S. was unclear. Primary sewage effluent samples were collected seasonally from seven wastewater treatme...

  2. Occurrence of bacteriophages infecting Bacteroides host strains (ARABA 84 and GB-124) in fecal samples of human and animal origin.

    Science.gov (United States)

    Diston, David; Wicki, Melanie

    2015-09-01

    Bacteriophage-based microbial source-tracking studies are an economical and simple way of identifying fecal sources in polluted water systems. Recently isolated Bacteroides spp. strains ARABA 84, and GB-124 have been shown to detect bacteriophages exclusively in aquatic systems impacted by human fecal material. To date, limited examination of the occurrence or concentration of phages capable of infecting Bacteroides fragilis strain GB-124 or B. thetaiotaomicron strain ARABA 84 in human and animal feces has been carried out. This study reports the prevalence rates and concentrations of phages infecting ARABA 84 and GB-124 host strains in human and a range of animal feces. Discrete human fecal samples (n=55) and pooled animal samples (n=46, representing the feces of over 230 animals) were examined for phages infecting the host strains ARABA 84, GB-124, and E. coli strain WG5. Both human Bacteroides host strains were highly specific (95% and 100% for ARABA 84 and GB-124, respectively), challenging results from previous studies. This study supports the use of Bacteroides strains GB-124 and ARABA 84 in fecal source tracking studies for the detection of human fecal contamination.

  3. Terminal Bacteroid Differentiation Is Associated With Variable Morphological Changes in Legume Species Belonging to the Inverted Repeat-Lacking Clade.

    Science.gov (United States)

    Montiel, Jesús; Szűcs, Attila; Boboescu, Iulian Z; Gherman, Vasile D; Kondorosi, Éva; Kereszt, Attila

    2016-03-01

    Medicago and closely related legume species from the inverted repeat-lacking clade (IRLC) impose terminal differentiation onto their bacterial endosymbionts, manifested in genome endoreduplication, cell enlargement, and loss of cell-division capacity. Nodule-specific cysteine-rich (NCR) secreted host peptides are plant effectors of this process. As bacteroids in other IRLC legumes, such as Cicer arietinum and Glycyrrhiza lepidota, were reported not to display features of terminal differentiation, we investigated the fate of bacteroids in species from these genera as well as in four other species representing distinct genera of the phylogenetic tree for this clade. Bacteroids in all tested legumes proved to be larger in size and DNA content than cultured cells; however, the degree of cell elongation was rather variable in the different species. In addition, the reproductive ability of the bacteroids isolated from these legumes was remarkably reduced. In all IRLC species with available sequence data, the existence of NCR genes was found. These results indicate that IRLC legumes provoke terminal differentiation of their endosymbionts with different morphotypes, probably with the help of NCR peptides.

  4. Bacteroides fragilis in biopsies of patients with major abscesses and diabetic foot infections: direct molecular versus culture-based detection

    OpenAIRE

    Stappers, Mark H. T.; Hagen, Ferry; Reimnitz, Peter; Mouton, Johan W.; Meis, Jacques F.; Gyssens, Inge C

    2016-01-01

    Direct determination by pathogen-specific real-time PCR assay for Bacteroides fragilis was compared to culture in major abscess and diabetic foot infection biopsy samples. Real-time PCR resulted in an increased detection rate of 12% for B. fragilis and could improve the detection of B. fragilis in clinical samples. (C) 2016 Elsevier Inc. All rights reserved.

  5. Bacteroides fragilis induce necrosis on mice peritoneal macrophages: In vitro and in vivo assays

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, J.M.B.D., E-mail: jmanya@terra.com.br [Laboratorio de Tecnologia em Cultura de Celulas, UEZO, Rio de Janeiro (Brazil); Laboratorio de Biologia de Anaerobios, IMPPG, UFRJ, Rio de Janeiro (Brazil); Seabra, S.H. [Laboratorio de Tecnologia em Cultura de Celulas, UEZO, Rio de Janeiro (Brazil); Vallim, D.C. [Instituto Oswaldo Cruz, Rio de Janeiro (Brazil); Americo, M.A.; Fracallanza, S.E.L. [Laboratorio de Bacteriologia Medica, IMPPG, UFRJ, Rio de Janeiro (Brazil); Vommaro, R.C. [Laboratorio de Ultra-estrutura Celular Hertha Meyer, IBCCF, UFRJ (Brazil); Domingues, R.M.C.P. [Laboratorio de Biologia de Anaerobios, IMPPG, UFRJ, Rio de Janeiro (Brazil)

    2009-10-02

    Bacteroides fragilis is an anaerobic bacteria component of human intestinal microbiota and agent of infections. In the host B. fragilis interacts with macrophages, which produces toxic radicals like NO. The interaction of activated mice peritoneal macrophages with four strains of B. fragilis was evaluated on this study. Previously was shown that such strains could cause metabolic and morphologic alterations related to macrophage death. In this work propidium iodide staining showed the strains inducing macrophage necrosis in that the labeling was evident. Besides nitroblue tetrazolium test showed that B. fragilis stimulates macrophage to produce oxygen radicals. In vivo assays performed in BalbC mice have results similar to those for in vitro tests as well as scanning electron microscopy, which showed the same surface pore-like structures observed in vitro before. The results revealed that B. fragilis strains studied lead to macrophage death by a process similar to necrosis.

  6. Levan Enhances Associated Growth of Bacteroides, Escherichia, Streptococcus and Faecalibacterium in Fecal Microbiota

    DEFF Research Database (Denmark)

    Adamberg, Kaarel; Tomson, Katrin; Talve, Tiina

    2015-01-01

    were determined. The composition of fecal microbiota and profile of metabolites changed in response to substrate (levan and amino acids) availability. The main products of levan metabolism were acetic, lactic, butyric, propionic and succinic acids and carbon dioxide. Associated growth of levan....... Eleven fecal samples from healthy donors were incubated in phosphate-buffered defined medium with or without levan supplementation and varying presence of amino acids. The generation of heat, changes in pH and microbiota composition, concentrations of produced and consumed metabolites during the growth......-degrading (e.g. Bacteroides) and butyric acid-producing (e.g. Faecalibacterium) taxa was observed in levan-supplemented media. The study shows that the capacity of levan and possibly also other dietary fibers/prebiotics to modulate the composition and function of colon microbiota can be predicted by using...

  7. Comparative antimicrobial efficacy of Metapex, Metronidazole, BioPure MTAD, Aztreonam on Bacteroides fragilis and Propionibacterium acne

    Directory of Open Access Journals (Sweden)

    Rajkumar Balakrishnan

    2013-01-01

    Full Text Available Aim: The purpose of this study was to evaluate the comparative antibacterial efficacy of Biopure MTAD, Metapex, Metronidazole, and Aztreonam against two obligate anerobic bacteria. Materials and Methods: Antimicrobial efficacy of selected medicaments against two obligate anaerobic bacteria Bacteroides fragilis and Propionibacterium acnes was done by Agar disc-diffusion method. Pre-sterilized Whatman paper discs, 6 mm in diameter and soaked with the test solution, were prepared and placed onto the previously seeded agar Petri plates. Each plate was incubated in anaerobic jar for anerobic environment at 37°C for 48 hours. A zone of inhibition was recorded for each plate and the results were analysed statistically. Saline and ethanol used as control group in this study. Results: Biopure MTAD, Metapex and Metronidazole were effective against all the selected microorganisms. Aztreonam was effective against Bacteroides fragilis. Saline and ethanol used as control were ineffective. Conclusions: Metronidazole showed the superior antibacterial property amongst the tested medicaments.

  8. Identification of antimicrobial resistance genes in multidrug-resistant clinical Bacteroides fragilis isolates by whole genome shotgun sequencing

    DEFF Research Database (Denmark)

    Sydenham, Thomas Vognbjerg; Sóki, József; Hasman, Henrik;

    2015-01-01

    Bacteroides fragilis constitutes the most frequent anaerobic bacterium causing bacteremia in humans. The genetic background for antimicrobial resistance in B. fragilis is diverse with some genes requiring insertion sequence (IS) elements inserted upstream for increased expression. To evaluate whole...... genetic data will most likely require complete or nearly complete genomes. Current approaches to this are laborious and/or costly. Emerging technologies such as nanopore based single DNA strand sensing could perhaps provide a solution in the future....

  9. First national survey of antibiotic susceptibility of the Bacteroides fragilis group: emerging resistance to carbapenems in Argentina.

    Science.gov (United States)

    Fernández-Canigia, Liliana; Litterio, Mirta; Legaria, María C; Castello, Liliana; Predari, Silvia C; Di Martino, Ana; Rossetti, Adelaida; Rollet, Raquel; Carloni, Graciela; Bianchini, Hebe; Cejas, Daniela; Radice, Marcela; Gutkind, Gabriel

    2012-03-01

    The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. Resistance to imipenem, doripenem, and ertapenem was observed in 1.1%, 1.6%, and 2.3% of B. fragilis group strains, respectively. B. fragilis species showed a resistance profile of 1.5% to imipenem, 1.9% to doripenem, and 2.4% to ertapenem. This is the first report of carbapenem resistance in Argentina. The cfiA gene was present in 8 out of 23 isolates, all of them belonging to the B. fragilis species and displaying reduced susceptibility or resistance to carbapenems (MICs ≥ 4 μg/ml). Three out of eight cfiA-positive isolates were fully resistant to carbapenems, while 5 out of 8 isolates showed low-level resistance (MICs, 4 to 8 μg/ml). The inhibition by EDTA was a good predictor of the presence of metallo-β-lactamases in the fully resistant B. fragilis strains, but discrepant results were observed for low-level resistant isolates. B. fragilis was more susceptible to antimicrobial agents than other Bacteroides species. Bacteroides vulgatus species was the most resistant to ampicillin-sulbactam and piperacillin-tazobactam, and B. thetaiotaomicron/ovatus strains showed the highest level of resistance to carbapenems, with an unknown resistance mechanism. B. vulgatus and the uncommon non-Bacteroides fragilis species were the most resistant to moxifloxacin, showing an overall resistance rate of 15.1%.

  10. A Closer Look at Bacteroides: Phylogenetic Relationship and Genomic Implications of a Life in the Human Gut

    DEFF Research Database (Denmark)

    Karlsson, Fredrik H.; Ussery, David; Nielsen, Jens;

    2011-01-01

    The human gut is extremely densely inhabited by bacteria mainly from two phyla, Bacteroidetes and Firmicutes, and there is a great interest in analyzing whole-genome sequences for these species because of their relation to human health and disease. Here, we do whole-genome comparison of 105 Bacte...... of members of the Bacteroidetes/Chlorobi phylum by whole genome comparison. Gut living Bacteroides have an enriched set of glycan, vitamin, and cofactor enzymes important for diet digestion.......The human gut is extremely densely inhabited by bacteria mainly from two phyla, Bacteroidetes and Firmicutes, and there is a great interest in analyzing whole-genome sequences for these species because of their relation to human health and disease. Here, we do whole-genome comparison of 105...... Bacteroidetes/Chlorobi genomes to elucidate their phylogenetic relationship and to gain insight into what is separating the gut living Bacteroides and Parabacteroides genera from other Bacteroidetes/Chlorobi species. A comprehensive analysis shows that Bacteroides species have a higher number...

  11. Decrease in anaerobe-related bacteraemias and increase in Bacteroides species isolation rate from 1998 to 2007: a retrospective study.

    Science.gov (United States)

    Lazarovitch, Tsilia; Freimann, Sarit; Shapira, Galina; Blank, Helena

    2010-06-01

    Conflicting data have accumulated in recent years regarding the incidence of anaerobic bacteraemias. The aim of this study was to determine the prevalence of bacteraemias due to anaerobic bacteria and evaluate the importance of anaerobic blood cultures in a university hospital in Israel. A retrospective survey which focused on anaerobic blood culture bottles was performed on blood cultures received in our laboratory during the decade from January 1998 to December 2007. Anaerobic-related bacteraemias decreased during that period, whereas a significant increase was observed in Bacteroides species isolated from the blood cultures (from 18% during 1998-2002 to 43% during 2003-2007). Comparison of the medical records of 54 patients with Bacteroides-related bacteraemia during the two end periods (1998-1999 and 2006-2007) revealed a marked increase in complex underlying diseases. Hypertension and diabetes mellitus type II were found in 29% of the patients in 1998-1999 and increased to 43-45% of the patients in 2006-2007. Ischemic heart disease also increased from 14% of the patients in 1998-1999 to 43% in 2006-2007. We conclude that although positive anaerobic blood cultures account for a small percentage of positive blood samples, the growing involvement of Bacteroides species-related bacteraemias together with an increase in complex underlying diseases in these patients emphasize the importance of anaerobic blood cultures, particularly in patients with co-morbidities.

  12. Polyamine catabolism contributes to enterotoxigenic Bacteroides fragilis-induced colon tumorigenesis.

    Science.gov (United States)

    Goodwin, Andrew C; Destefano Shields, Christina E; Wu, Shaoguang; Huso, David L; Wu, XinQun; Murray-Stewart, Tracy R; Hacker-Prietz, Amy; Rabizadeh, Shervin; Woster, Patrick M; Sears, Cynthia L; Casero, Robert A

    2011-09-13

    It is estimated that the etiology of 20-30% of epithelial cancers is directly associated with inflammation, although the direct molecular events linking inflammation and carcinogenesis are poorly defined. In the context of gastrointestinal disease, the bacterium enterotoxigenic Bacteroides fragilis (ETBF) is a significant source of chronic inflammation and has been implicated as a risk factor for colorectal cancer. Spermine oxidase (SMO) is a polyamine catabolic enzyme that is highly inducible by inflammatory stimuli resulting in increased reactive oxygen species (ROS) and DNA damage. We now demonstrate that purified B. fragilis toxin (BFT) up-regulates SMO in HT29/c1 and T84 colonic epithelial cells, resulting in SMO-dependent generation of ROS and induction of γ-H2A.x, a marker of DNA damage. Further, ETBF-induced colitis in C57BL/6 mice is associated with increased SMO expression and treatment of mice with an inhibitor of polyamine catabolism, N(1),N(4)-bis(2,3-butandienyl)-1,4-butanediamine (MDL 72527), significantly reduces ETBF-induced chronic inflammation and proliferation. Most importantly, in the multiple intestinal neoplasia (Min) mouse model, treatment with MDL 72527 reduces ETBF-induced colon tumorigenesis by 69% (P < 0.001). The results of these studies indicate that SMO is a source of bacteria-induced ROS directly associated with tumorigenesis and could serve as a unique target for chemoprevention.

  13. Polyamine catabolism contributes to enterotoxigenic Bacteroides fragilis-induced colon tumorigenesis

    Science.gov (United States)

    Goodwin, Andrew C.; Shields, Christina E. Destefano; Wu, Shaoguang; Huso, David L.; Wu, XinQun; Murray-Stewart, Tracy R.; Hacker-Prietz, Amy; Rabizadeh, Shervin; Woster, Patrick M.; Sears, Cynthia L.; Casero, Robert A.

    2011-01-01

    It is estimated that the etiology of 20–30% of epithelial cancers is directly associated with inflammation, although the direct molecular events linking inflammation and carcinogenesis are poorly defined. In the context of gastrointestinal disease, the bacterium enterotoxigenic Bacteroides fragilis (ETBF) is a significant source of chronic inflammation and has been implicated as a risk factor for colorectal cancer. Spermine oxidase (SMO) is a polyamine catabolic enzyme that is highly inducible by inflammatory stimuli resulting in increased reactive oxygen species (ROS) and DNA damage. We now demonstrate that purified B. fragilis toxin (BFT) up-regulates SMO in HT29/c1 and T84 colonic epithelial cells, resulting in SMO-dependent generation of ROS and induction of γ-H2A.x, a marker of DNA damage. Further, ETBF-induced colitis in C57BL/6 mice is associated with increased SMO expression and treatment of mice with an inhibitor of polyamine catabolism, N1,N4-bis(2,3-butandienyl)-1,4-butanediamine (MDL 72527), significantly reduces ETBF-induced chronic inflammation and proliferation. Most importantly, in the multiple intestinal neoplasia (Min) mouse model, treatment with MDL 72527 reduces ETBF-induced colon tumorigenesis by 69% (P < 0.001). The results of these studies indicate that SMO is a source of bacteria-induced ROS directly associated with tumorigenesis and could serve as a unique target for chemoprevention. PMID:21876161

  14. Two New Xylanases with Different Substrate Specificities from the Human Gut Bacterium Bacteroides intestinalis DSM 17393

    KAUST Repository

    Hong, Pei-Ying

    2014-01-24

    Xylan is an abundant plant cell wall polysaccharide and is a dominant component of dietary fiber. Bacteria in the distal human gastrointestinal tract produce xylanase enzymes to initiate the degradation of this complex heteropolymer. These xylanases typically derive from glycoside hydrolase (GH) families 10 and 11; however, analysis of the genome sequence of the xylan-degrading human gut bacterium Bacteroides intestinalis DSM 17393 revealed the presence of two putative GH8 xylanases. In the current study, we demonstrate that the two genes encode enzymes that differ in activity. The xyn8A gene encodes an endoxylanase (Xyn8A), and rex8A encodes a reducing-end xylose-releasing exo-oligoxylanase (Rex8A). Xyn8A hydrolyzed both xylopentaose (X5) and xylohexaose (X6) to a mixture of xylobiose (X2) and xylotriose (X3), while Rex8A hydrolyzed X3 through X6 to a mixture of xylose (X1) and X2. Moreover, rex8A is located downstream of a GH3 gene (xyl3A) that was demonstrated to exhibit β-xylosidase activity and would be able to further hydrolyze X2 to X1. Mutational analyses of putative active site residues of both Xyn8A and Rex8A confirm their importance in catalysis by these enzymes. Recent genome sequences of gut bacteria reveal an increase in GH8 Rex enzymes, especially among the Bacteroidetes, indicating that these genes contribute to xylan utilization in the human gut.

  15. Prebiotic galactooligosaccharides activate mucin and pectic galactan utilization pathways in the human gut symbiont Bacteroides thetaiotaomicron

    Science.gov (United States)

    Lammerts van Bueren, Alicia; Mulder, Marieke; Leeuwen, Sander van; Dijkhuizen, Lubbert

    2017-01-01

    Galactooligosaccharides (GOS) are prebiotic carbohydrates that impart changes in the gut bacterial composition of formula-fed infants to more closely resemble that of breast-fed infants. Consuming human milk oligosaccharides (HMOs) provides specific bacterial strains with an advantage for colonizing the infant intestine. These same effects are seen in infants after GOS consumption, however GOS are very complex mixtures and the underlying molecular mechanisms of how GOS mimic HMOs are relatively unknown. Here we studied the effects of GOS utilization on a prominent gut symbiont, Bacteroides thetaiotaomicron, which has been previously shown to consume HMOs via mucin O-glycan degradation pathways. We show that several pathways for targeting O-mucin glycans are activated in B. thetaiotaomicron by GOS, as well as the galactan utilization sytem. Characterization of the endo-galactanase from this system identified activity on various longer GOS substrates while a subset of GOS compounds were identified as potential activators of mucin glycan metabolism in B. thetaiotaomicron. Our results show that GOS functions as an inducer of mucin-glycan pathways while providing a nutrient source in the form of β-(1 → 4)-galactan. These metabolic features of GOS mixtures may serve to explain the beneficial effects that are seen for GOS supplemented infant formula. PMID:28091546

  16. The dissemination of C10 cysteine protease genes in Bacteroides fragilis by mobile genetic elements

    LENUS (Irish Health Repository)

    Thornton, Roibeard F

    2010-04-23

    Abstract Background The C10 family of cysteine proteases includes enzymes that contribute to the virulence of bacterial pathogens, such as SpeB in Streptococcus pyogenes. The presence of homologues of cysteine protease genes in human commensal organisms has not been examined. Bacteroides fragilis is a member of the dominant Bacteroidetes phylum of the human intestinal microbiota, and is a significant opportunistic pathogen. Results Four homologues of the streptococcal virulence factor SpeB were identified in the B. fragilis genome. These four protease genes, two were directly contiguous to open reading frames predicted to encode staphostatin-like inhibitors, with which the protease genes were co-transcribed. Two of these protease genes are unique to B. fragilis 638R and are associated with two large genomic insertions. Gene annotation indicated that one of these insertions was a conjugative Tn-like element and the other was a prophage-like element, which was shown to be capable of excision. Homologues of the B. fragilis C10 protease genes were present in a panel of clinical isolates, and in DNA extracted from normal human faecal microbiota. Conclusions This study suggests a mechanism for the evolution and dissemination of an important class of protease in major members of the normal human microbiota.

  17. Absence of Porphyromonas asaccharolytica, Bacteroides fragilis and Chlamydia pneumoniae in human subgingival plaque.

    Science.gov (United States)

    Tran, T; Flynn, M J; Chen, C; Slots, J

    1997-12-01

    Little is known about the presence of common medical pathogens in the human oral cavity. Using a 16S rRNA-based PCR identification method, this study determined the occurrence of Porphyromonas asaccharolytica, Bacteroides fragilis and Chlamydia pneumoniae in subgingival plaque from 50 adults with advanced periodontitis. Each patient contributed samples from 3 deep periodontal pockets collected by paper points. The PCR primers were for P. asaccharolytica 5'-CTC TAG CTA GAG TGT ACT GG-3' and 5'-ATA GGG TTT ATA GAT TAG CTC TCT-3', for B. fragilis 5'-AAT GAT TCC GCA TGG TTT CAT TA-3' and 5'-GCG GTG ATT GCT CAC TGA CA-3', and for C. pneumoniae 5'- TGA CAA CTG TAG AAA TAC AGC-3' and 5'-CGC CTC TCT CCT ATA AAT-3'. The primers yielded a single amplicon with the respective reference strains and produced no amplicon with colonies of 25 groups of oral organisms. None of the three test species were detected in any of the 50 pooled subgingival samples tested. P. asaccharyolytica, B. fragilis and C. pneumoniae do not seem to be part of the periodontopathic microbiota in humans.

  18. Characterization of certain proteinase isoenzymes produced by benign and virulent strains of Bacteroides nodosus.

    Science.gov (United States)

    Green, R S

    1985-11-01

    Three proteinase isoenzymes from one benign strain of Bacteroides nodosus and five proteinase isoenzymes from each of two virulent strains of B. nodosus were purified by horizontal slab polyacrylamide gel electrophoresis. The purified isoenzymes hydrolysed casein, collagen I, collagen III, elastin, alpha-elastin, fibrinogen, gelatin, haemoglobin and alpha-keratin. The pH optima of all the isoenzymes lay between 7.25 and 9.5, the range of 8.75-9.25 being common to all. The isoenzymes were inhibited by phenylmethylsulphonyl fluoride, diphenylcarbamyl chloride, L-(1-tosylamide-2-phenyl)ethyl chloromethyl ketone, EGTA and EDTA, indicating that they were chymotrypsin-like serine proteinases that require a metal ion for stability or activity. EDTA inhibition was not reversed by addition of Ca2+ or Mg2+. Some isoenzymes were activated by Mg2+, Ca2+, Cr3+ and Se4+ and all were inhibited by Fe2+, Co2+, Cu2+, Zn2+, Cd2+ and Hg2+. Isoenzymes from benign strains had a lower temperature stability, losing all activity at 55 degrees C, whereas those from virulent strains lost all activity at 60 degrees C.

  19. A novel strain of Bacteroides fragilis enhances phagocytosis and polarises M1 macrophages

    Science.gov (United States)

    Deng, Huimin; Li, Zhengchao; Tan, Yafang; Guo, Zhaobiao; Liu, Yangyang; Wang, Ye; Yuan, Yuan; Yang, Ruifu; Bi, Yujing; Bai, Yang; Zhi, Fachao

    2016-01-01

    Commensal Bacteroides fragilis possesses immune-regulatory characteristics. Consequently, it has been proposed as a potential novel probiotic because of its therapeutic effects on immune imbalance, mental disorders and inflammatory diseases. Macrophages play a central role in the immune response, developing either a classical-M1 or an alternative-M2 phenotype after stimulation with various signals. The interactions between macrophages and B. fragilis, however, remain to be defined. Here, a new isolate of B. fragilis, ZY-312, was shown to possess admirable properties, including tolerance to simulated gastric fluid, intestinal fluid and ox bile, and good safety (MOI = 100, 200) and adherent ability (MOI = 100) to LoVo cells. Isolate ZY-312 cell lysate promoted phagocytosis of fluorescent microspheres and pathogenic bacteria in bone marrow-derived macrophage (BMDM) cells. Gene expression of IL-12, iNOS and IL-1β in BMDM cells was increased after treatment with ZY-312, indicating the induction of M1 macrophages, consistent with enhanced secretion of NO. Cell surface expression of CD80 and CD86 was also increased. This study is the first to demonstrate that B. fragilis enhances the phagocytic functions of macrophages, polarising them to an M1 phenotype. Our findings provide insight into the close relationship between B. fragilis and the innate immune system. PMID:27381366

  20. Enterotoxigenic and non-enterotoxigenic Bacteroides fragilis from fecal microbiota of children

    Directory of Open Access Journals (Sweden)

    Aline Ignacio

    2015-01-01

    Full Text Available Enterotoxigenic Bacteroides fragilis (ETBF is an important part of the human and animal intestinal microbiota and is commonly associated with diarrhea. ETBF strains produce an enterotoxin encoded by the bft gene located in the B. fragilispathogenicity island (BfPAI. Non-enterotoxigenic B. fragilis(NTBF strains lack the BfPAI and usually show two different genetic patterns, II and III, based on the absence or presence of a BfPAI-flanking region, respectively. The incidence of ETBF and NTBF strains in fecal samples isolated from children without acute diarrhea or any other intestinal disorders was determined. All 84 fecal samples evaluated were B. fragilis-positive by PCR, four of them harbored the bft gene, 27 contained the NTBF pattern III DNA sequence, and 52 were considered to be NTBF pattern II samples. One sample was positive for both ETBF and NTBF pattern III DNA sequences. All 19 B. fragilis strains isolated by the culture method were bft-negative, 9 belonged to pattern III and 10 to pattern II. We present an updated overview of the ETBF and NTBF incidence in the fecal microbiota of children from Sao Paulo City, Brazil.

  1. Oxygen-independent killing of Bacteroides fragilis by granule extracts from human polymorphonuclear leukocytes.

    Science.gov (United States)

    Wetherall, B L; Pruul, H; McDonald, P J

    1984-03-01

    Granule proteins from human neutrophils were prepared by extraction with acetate, and their antibacterial activity against Bacteroides fragilis was determined. Activity was highly dependent on pH; greatest killing occurred at the most acid pH tested (pH 5.0). Optimum activity was observed at physiological ionic strength and low bacterial numbers. Killing was inhibited by incubation temperatures of less than 37 degrees C. Eight times more extract was required to kill 50% of stationary-phase bacteria, compared with those growing in logarithmic phase. The antibacterial effect of granule extract was destroyed by boiling, but some activity was retained after heating to 56 degrees C and 80 degrees C. Granule extract activity was tested under conditions in which oxygen-dependent antibacterial systems were inhibited. The rate and extent of killing was not affected by anaerobiosis, sodium azide, or cysteine hydrochloride. These results suggest that the activity of granule extract is independent of oxidative antibacterial systems, and therefore, under conditions that occur in anaerobic infections, potent leukocyte granule-associated mechanisms exist for the destruction of B. fragilis.

  2. Structural and functional diversity of metalloproteinases encoded by the Bacteroides fragilis pathogenicity island.

    Science.gov (United States)

    Shiryaev, Sergey A; Aleshin, Alexander E; Muranaka, Norihito; Kukreja, Muskan; Routenberg, David A; Remacle, Albert G; Liddington, Robert C; Cieplak, Piotr; Kozlov, Igor A; Strongin, Alex Y

    2014-06-01

    Bacteroides fragilis causes the majority of anaerobic infections in humans. The presence of a pathogenicity island in the genome discriminates pathogenic and commensal B. fragilis strains. The island encodes metalloproteinase II (MPII), a potential virulence protein, and one of three homologous fragilysin isozymes (FRA; also termed B. fragilis toxin or BFT). Here, we report biochemical data on the structural-functional characteristics of the B. fragilis pathogenicity island proteases by reporting the crystal structure of MPII at 2.13 Å resolution, combined with detailed characterization of the cleavage preferences of MPII and FRA3 (as a representative of the FRA isoforms), identified using a high-throughput peptide cleavage assay with 18 583 substrate peptides. We suggest that the evolution of the MPII catalytic domain can be traced to human and archaebacterial proteinases, whereas the prodomain fold is a feature specific to MPII and FRA. We conclude that the catalytic domain of both MPII and FRA3 evolved differently relative to the prodomain, and that the prodomain evolved specifically to fit the B. fragilis pathogenicity. Overall, our data provide insights into the evolution of cleavage specificity and activation mechanisms in the virulent metalloproteinases.

  3. The dissemination of C10 cysteine protease genes in Bacteroides fragilis by mobile genetic elements

    Directory of Open Access Journals (Sweden)

    Kagawa Todd F

    2010-04-01

    Full Text Available Abstract Background The C10 family of cysteine proteases includes enzymes that contribute to the virulence of bacterial pathogens, such as SpeB in Streptococcus pyogenes. The presence of homologues of cysteine protease genes in human commensal organisms has not been examined. Bacteroides fragilis is a member of the dominant Bacteroidetes phylum of the human intestinal microbiota, and is a significant opportunistic pathogen. Results Four homologues of the streptococcal virulence factor SpeB were identified in the B. fragilis genome. These four protease genes, two were directly contiguous to open reading frames predicted to encode staphostatin-like inhibitors, with which the protease genes were co-transcribed. Two of these protease genes are unique to B. fragilis 638R and are associated with two large genomic insertions. Gene annotation indicated that one of these insertions was a conjugative Tn-like element and the other was a prophage-like element, which was shown to be capable of excision. Homologues of the B. fragilis C10 protease genes were present in a panel of clinical isolates, and in DNA extracted from normal human faecal microbiota. Conclusions This study suggests a mechanism for the evolution and dissemination of an important class of protease in major members of the normal human microbiota.

  4. Differential proteomic analysis of outer membrane enriched extracts of Bacteroides fragilis grown under bile salts stress.

    Science.gov (United States)

    Boente, Renata F; Pauer, Heidi; Silva, Deborah N S; Filho, Joaquim Santos; Sandim, Vanessa; Antunes, Luis Caetano M; Ferreira, Rosana Barreto Rocha; Zingali, Russolina B; Domingues, Regina M C P; Lobo, Leandro A

    2016-06-01

    Bacteroides fragilis is the most commonly isolated anaerobic bacteria from infectious processes. Several virulence traits contribute to the pathogenic nature of this bacterium, including the ability to tolerate the high concentrations of bile found in the gastrointestinal tract (GIT). The activity of bile salts is similar to detergents and may lead to membrane permeabilization and cell death. Modulation of outer membrane proteins (OMPs) is considered a crucial event to bile salts resistance. The primary objective of the current work was to identify B. fragilis proteins associated with the stress induced by high concentration of bile salts. The outer membrane of B. fragilis strain 638R was isolated after growth either in the presence of 2% conjugated bile salts or without bile salts. The membrane fractions were separated on SDS-PAGE and analyzed by ESI-Q/TOF tandem mass spectrometry. A total of 37 proteins were identified; among them nine were found to be expressed exclusively in the absence of bile salts whereas eight proteins were expressed only in the presence of bile salts. These proteins are related to cellular functions such as transport through membrane, nutrient uptake, and protein-protein interactions. This study demonstrates the alteration of OMPs composition in B. fragilis during bile salts stress resistance and adaptation to environmental changes. Proteomics of OMPs was also shown to be a useful approach in the identification of new targets for functional analyses.

  5. An orthologue of Bacteroides fragilis NanH is the principal sialidase in Tannerella forsythia.

    Science.gov (United States)

    Thompson, Hayley; Homer, Karen A; Rao, Susmitha; Booth, Veronica; Hosie, Arthur H F

    2009-06-01

    Sialidase activity is a putative virulence factor of the anaerobic periodontal pathogen Tannerella forsythia, but it is uncertain which genes encode this activity. Characterization of a putative sialidase, SiaHI, by others, indicated that this protein alone may not be responsible for all of the sialidase activity. We describe a second sialidase in T. forsythia (TF0035), an orthologue of Bacteroides fragilis NanH, and its expression in Escherichia coli. Sialidase activity of the expressed NanH was confirmed by using 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid as a substrate. Biochemical characterization of the recombinant T. forsythia NanH indicated that it was active over a broad pH range, with optimum activity at pH 5.5. This enzyme has high affinity for 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid (K(m) of 32.9 +/- 10.3 microM) and rapidly releases 4-methylumbelliferone (V(max) of 170.8 +/- 11.8 nmol of 4-methylumbelliferone min(-1) mg of protein(-1)). E. coli lysates containing recombinant T. forsythia NanH cleave sialic acid from a range of substrates, with a preference for alpha2-3 glycosidic linkages. The genes adjacent to nanH encode proteins apparently involved in the metabolism of sialic acid, indicating that the NanH sialidase is likely to be involved in nutrient acquisition.

  6. Epitope identification for a panel of anti-Sinorhizobium meliloti monoclonal antibodies and application to the analysis of K antigens and lipopolysaccharides from bacteroids

    Energy Technology Data Exchange (ETDEWEB)

    Reuhs, B.L.; Stephens, S.B.; Geller, D.P.; Kim, J.S.; Glenn, J.; Przytycki, J.; Ojanen-Reuhs, T.

    1999-11-01

    In two published reports using monoclonal antibodies (MAbs) generated against whole cells, Olsen et al. showed that strain-specific antigens on the surface of cultured cells of Sinorhyzobium meliloti were diminished or absent in the endophytic cells (bacteroids) recovered from alfalfa nodules, whereas two common antigens were not affected by bacterial differentiation. The nature of the antigens, however, were not determined in those studies. For this report, the epitopes for five of the anti-S. meliloti MAbs were identified by polyacrylamide gel electrophoresis-immunoblot analyses of the polysaccharides extracted from S. meliloti and Sinorhizobium fridii. This showed that the strain-specific MAbs recognized K antigens, whereas the strain-cross-reactive MAbs recognized the lipopolysaccharide (LPS) core. The MAbs were then used in the analysis of the LPS and K antigens extracted from S. meliloti bacteroids, which had been recovered from the root nodules of alfalfa, and the results supported the findings of Olsen et al. The size range of the K antigens from bacteroids of S. meliloti NRG247 on polyacrylamide gels was altered, and the epitope was greatly diminished in abundance compared to those from the cultured cells, and no K antigens were detected in the S. meliloti NRG185 bacteroid extract. In contrast to the K antigens, the LPS core appeared to be similar in both cultured cells and bacteroids, although a higher proportion of the LPS fractionated into the organic phase during the phenol-water extraction of the bacteroid polysaccharides. Importantly, immunoblot analysis with an anti-LPS MAb showed that smooth LPS production was modified in the bacteroids.

  7. Loss of NHE3 alters gut microbiota composition and influences Bacteroides thetaiotaomicron growth.

    Science.gov (United States)

    Engevik, Melinda A; Aihara, Eitaro; Montrose, Marshall H; Shull, Gary E; Hassett, Daniel J; Worrell, Roger T

    2013-11-15

    Changes in the intestinal microbiota have been linked to diabetes, obesity, inflammatory bowel disease, and Clostridium difficile (C. difficile)-associated disease. Despite this, it remains unclear how the intestinal environment, set by ion transport, affects luminal and mucosa-associated bacterial composition. Na(+)/H(+)-exchanger isoform 3 (NHE3), a target of C. difficile toxin B, plays an integral role in intestinal Na(+) absorption. Thus the NHE3-deficient mouse model was chosen to examine the effect of pH and ion composition on bacterial growth. We hypothesized that ion transport-induced change in the intestinal environment would lead to alteration of the microbiota. Region-specific changes in ion composition and pH correlated with region-specific alteration of luminal and mucosal-associated bacteria with general decreases in Firmicutes and increases in Bacteroidetes members. Bacteroides thetaiotaomicron (B. thetaiotaomicron) increased in NHE3(-/-) terminal ileum and was examined in vitro to determine whether altered Na(+) was sufficient to affect growth. Increased in vitro growth of B. thetaiotaomicron occurred in 43 mM Na(+) correlating with the NHE3(-/-) mouse terminal ileum [Na(+)]. NHE3(-/-) terminal ileum displayed increased fut2 mRNA and fucosylation correlating with B. thetaiotaomicron growth. Inoculation of B. thetaiotaomicron in wild-type and NHE3(-/-) terminal ileum organoids displayed increased fut2 and fucosylation, indicating that B. thetaiotaomicron alone is sufficient for the increased fucosylation seen in vivo. These data demonstrate that loss of NHE3 alters the intestinal environment, leading to region-specific changes in bacteria, and shed light on the growth requirements of some gut microbiota members, which is vital for creating better treatments of complex diseases with an altered gut microbiota.

  8. Bacteroides fragilis lipopolysaccharide and inflammatory signaling in Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Walter J. Lukiw

    2016-09-01

    Full Text Available The human microbiome consists of ~3.8x1013 symbiotic microorganisms that form a highly complex and dynamic ecosystem: the gastrointestinal (GI tract constitutes the largest repository of the human microbiome by far, and its impact on human neurological health and disease is becoming increasingly appreciated. Bacteroidetes, the largest phylum of gram-negative bacteria in the GI tract microbiome, while generally beneficial to the host when confined to the GI tract, have potential to secrete a remarkably complex array of pro-inflammatory neurotoxins that include surface lipopolysaccharides (LPSs and toxic proteolytic species. The deleterious effects of these bacterial exudates appear to become more important as GI tract and blood-brain barriers alter or increase their permeability with aging and disease. For example, presence of the unique LPSs of the abundant Bacteroidetes species Bacteroides fragilis (BF-LPS in the serum represents a major contributing factor to systemic inflammation. BF-LPS is further recognized by TLR2, TLR4 and/or CD14 microglial cell receptors as are the pro-inflammatory 42 amino acid amyloid-beta (Aβ42 peptides that characterize Alzheimer’s disease (AD brain. Here we provide the first evidence that BF-LPS exposure to human primary brain cells is an exceptionally potent inducer of the pro-inflammatory transcription factor NF-kB (p50/p65 complex, a known trigger in the expression of pathogenic pathways involved in inflammatory neurodegeneration. This ‘Perspectives communication’ will in addition highlight work from recent studies that advance novel and emerging concepts on the potential contribution of microbiome-generated factors, such as BF-LPS, in driving pro-inflammatory degenerative neuropathology in the AD brain.

  9. Exploratory investigation of Bacteroides fragilis transcriptional response during in vitro exposure to subinhibitory concentration of metronidazole

    Directory of Open Access Journals (Sweden)

    Michele Cristine Ribeiro Freitas

    2016-09-01

    Full Text Available Bacteroides fragilis, member from commensal gut microbiota, is an important pathogen associated to endogenous infections and metronidazole remains a valuable antibiotic for the treatment of these infections, although bacterial resistance is widely reported. Considering the need of a better understanding on the global mechanisms by which B. fragilis survive upon metronidazole exposure, we performed a RNA-seq transcriptomic approach with validation of gene expression results by qPCR. Bacteria strains were selected after in vitro subcultures with subinhibitory concentration (SIC of the drug. From a wild type B. fragilis ATCC 43859 four derivative strains were selected: 1st and 4th subcultures under metronidazole exposure and 1st and 4th subcultures after drug removal. According to global gene expression analysis, 2,146 protein coding genes were identified, of which a total of 1,618 (77% were assigned to a Gene Ontology term (GO, indicating that most known cellular functions were taken. Among these 2,146 protein coding genes, 377 were shared among all strains, suggesting that they are critical for B. fragilis survival. In order to identify distinct expression patterns, we also performed a K-means clustering analysis set to 15 groups. This analysis allowed us to detect the major activated or repressed genes encoding for enzymes which act in several metabolic pathways involved in metronidazole response such as drug activation, defense mechanisms against superoxide ions, high expression level of multidrug efflux pumps, and DNA repair. The strains collected after metronidazole removal were functionally more similar to those cultured under drug pressure, reinforcing that drug-exposure lead to drastic persistent changes in the B. fragilis gene expression patterns. These results may help to elucidate B. fragilis response during metronidazole exposure, mainly at SIC, contributing with information about bacterial survival strategies under stress conditions

  10. Bacteroides gingivalis antigens and bone resorbing activity in root surface fractions of periodontally involved teeth

    Energy Technology Data Exchange (ETDEWEB)

    Patters, M.R.; Landsberg, R.L.; Johansson, L.A.; Trummel, C.L.; Robertson, P.R. (Department of Periodontology, University of Connecticut, School of Dental Medicine, Farmington, Connecticut, U.S.A.)

    1982-01-01

    Bone resorbing activity and the presence of antigens of Bacteroides gingivalis were assessed in plaque, calculus, cementum, and dentin obtained from roots of teeth previously exposed to periodontitis. Each fraction was obtained by scaling the root surface. The fraction were extracted by stirring and sonication, and the soluble centrifuged, sterilized, dialyzed, and adjusted to equivalent protein concentrations. Cementum and dentin extracts from impacted teeth were prepared similarly and served as controls. Stimulation of bone resorption by each extract was assessed in organ cultures of fetal rat bones by measurement of release of previously-incorporated /sup 45/Ca from the bone into the medium. In some groups of teeth, calculus and cementum were treated with acid prior to scaling. Citric acid washes were recovered and dialyzed. An enzyme-linked immunosorbent assay (ELISA) was used to assess the extracts for the presence of antigens reactive with an antiserum to B. gingivalis. Significant stimulation of bone resorption was found in all calculus and periodontally-involved cementum preparations. ELISA showed significant levels of B.gingivalis antigens in plaque, calculus, and cementum of periodontally-involved teeth, but not in involved dentin nor in cementum or dentin of impact teeth. Treatment with citric acid removed essentially all B.gingivalis antigens from cementum but not calculus. The results suggest that substances which stimulate bone resorption and substances which react with B. gingivalis antiserum are present in surface plaque, calculus, and cementum or periodontally-involved teeth. These substances are not present in cementum and dentin of impacted teeth nor in dentin of periodontally-involved teeth. Treatment by both scaling and citric demineralization will remove most of these substances from cementum of teeth previously exposed to periodontitis.

  11. Exploratory Investigation of Bacteroides fragilis Transcriptional Response during In vitro Exposure to Subinhibitory Concentration of Metronidazole

    Science.gov (United States)

    de Freitas, Michele C. R.; Resende, Juliana A.; Ferreira-Machado, Alessandra B.; Saji, Guadalupe D. R. Q.; de Vasconcelos, Ana T. R.; da Silva, Vânia L.; Nicolás, Marisa F.; Diniz, Cláudio G.

    2016-01-01

    Bacteroides fragilis, member from commensal gut microbiota, is an important pathogen associated to endogenous infections and metronidazole remains a valuable antibiotic for the treatment of these infections, although bacterial resistance is widely reported. Considering the need of a better understanding on the global mechanisms by which B. fragilis survive upon metronidazole exposure, we performed a RNA-seq transcriptomic approach with validation of gene expression results by qPCR. Bacteria strains were selected after in vitro subcultures with subinhibitory concentration (SIC) of the drug. From a wild type B. fragilis ATCC 43859 four derivative strains were selected: first and fourth subcultures under metronidazole exposure and first and fourth subcultures after drug removal. According to global gene expression analysis, 2,146 protein coding genes were identified, of which a total of 1,618 (77%) were assigned to a Gene Ontology term (GO), indicating that most known cellular functions were taken. Among these 2,146 protein coding genes, 377 were shared among all strains, suggesting that they are critical for B. fragilis survival. In order to identify distinct expression patterns, we also performed a K-means clustering analysis set to 15 groups. This analysis allowed us to detect the major activated or repressed genes encoding for enzymes which act in several metabolic pathways involved in metronidazole response such as drug activation, defense mechanisms against superoxide ions, high expression level of multidrug efflux pumps, and DNA repair. The strains collected after metronidazole removal were functionally more similar to those cultured under drug pressure, reinforcing that drug-exposure lead to drastic persistent changes in the B. fragilis gene expression patterns. These results may help to elucidate B. fragilis response during metronidazole exposure, mainly at SIC, contributing with information about bacterial survival strategies under stress conditions in their

  12. The structure of BVU2987 from Bacteroides vulgatus reveals a superfamily of bacterial periplasmic proteins with possible inhibitory function

    OpenAIRE

    2010-01-01

    Proteins that contain the DUF2874 domain constitute a new Pfam family PF11396. Members of this family have predominantly been identified in microbes found in the human gut and oral cavity. The crystal structure of one member of this family, BVU2987 from Bacteroides vulgatus, has been determined, revealing a β-lactamase inhibitor protein-like structure with a tandem repeat of domains. Sequence analysis and structural comparisons reveal that BVU2987 and other DUF2874 proteins are related to β-l...

  13. The structure of BVU2987 from Bacteroides vulgatus reveals a superfamily of bacterial periplasmic proteins with possible inhibitory function.

    Science.gov (United States)

    Das, Debanu; Finn, Robert D; Carlton, Dennis; Miller, Mitchell D; Abdubek, Polat; Astakhova, Tamara; Axelrod, Herbert L; Bakolitsa, Constantina; Chen, Connie; Chiu, Hsiu Ju; Chiu, Michelle; Clayton, Thomas; Deller, Marc C; Duan, Lian; Ellrott, Kyle; Ernst, Dustin; Farr, Carol L; Feuerhelm, Julie; Grant, Joanna C; Grzechnik, Anna; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K; Klock, Heath E; Knuth, Mark W; Kozbial, Piotr; Krishna, S Sri; Kumar, Abhinav; Marciano, David; McMullan, Daniel; Morse, Andrew T; Nigoghossian, Edward; Nopakun, Amanda; Okach, Linda; Puckett, Christina; Reyes, Ron; Rife, Christopher L; Sefcovic, Natasha; Tien, Henry J; Trame, Christine B; van den Bedem, Henry; Weekes, Dana; Wooten, Tiffany; Xu, Qingping; Hodgson, Keith O; Wooley, John; Elsliger, Marc André; Deacon, Ashley M; Godzik, Adam; Lesley, Scott A; Wilson, Ian A

    2010-10-01

    Proteins that contain the DUF2874 domain constitute a new Pfam family PF11396. Members of this family have predominantly been identified in microbes found in the human gut and oral cavity. The crystal structure of one member of this family, BVU2987 from Bacteroides vulgatus, has been determined, revealing a β-lactamase inhibitor protein-like structure with a tandem repeat of domains. Sequence analysis and structural comparisons reveal that BVU2987 and other DUF2874 proteins are related to β-lactamase inhibitor protein, PepSY and SmpA_OmlA proteins and hence are likely to function as inhibitory proteins.

  14. Population structure and distribution of virulence-related genes of Bacteroides fragilis isolates from Korea and Japan.

    Science.gov (United States)

    Ko, Kwan Soo; Kuwahara, Tomomi; Lee, Kyungwon; Kook, Yoon-Hoh

    2009-07-01

    Sequences for rpoB, gyrB, pdiA, and ompA were determined from 63 Bacteroides fragilis isolates, which were from Korea and Japan and include 4 reference strains. All 4 gene sequences supported clear separation of the cfi(+) group from the cfi(-) group. Combined sequences of the 60 division I isolates (cfi(-)) produced 45 different clones. Apparent discordance of gene trees, index of association, maximum likelihood test, and homoplasy ratio all supported a high frequency of recombination. There was no association between the presence of virulence-related genes and phylogenetic clustering in any gene tree.

  15. Overexpression of BetS, a Sinorhizobium meliloti high-affinity betaine transporter, in bacteroids from Medicago sativa nodules sustains nitrogen fixation during early salt stress adaptation.

    Science.gov (United States)

    Boscari, Alexandre; Van de Sype, Ghislaine; Le Rudulier, Daniel; Mandon, Karine

    2006-08-01

    Sinorhizobium meliloti possesses several betaine transporters to cope with salt stress, and BetS represents a crucial high-affinity glycine and proline betaine uptake system involved in the rapid acquisition of betaines by cells subjected to osmotic upshock. Using a transcriptional lacZ (beta-galactosidase) fusion, we showed that betS is expressed during the establishment of the symbiosis and in mature nitrogen-fixing nodules. However, neither Nod nor Fix phenotypes were impaired in a betS mutant. BetS is functional in isolated bacteroids, and its activity is strongly activated by high osmolarity. In bacteroids from a betS mutant, glycine betaine and proline betaine uptake was reduced by 85 to 65%, indicating that BetS is a major component of the overall betaine uptake activity in bacteroids in response to osmotic stress. Upon betS overexpression (strain UNA349) in free-living cells, glycine betaine transport was 2.3-fold higher than in the wild-type strain. Interestingly, the accumulation of proline betaine, the endogenous betaine synthesized by alfalfa plants, was 41% higher in UNA349 bacteroids from alfalfa plants subjected to 1 week of salinization (0.3 M NaCl) than in wild-type bacteroids. In parallel, a much better maintenance of nitrogen fixation activity was observed in 7-day-salinized plants nodulated with the overexpressing strain than in wild-type nodulated plants. Taken altogether, these results are consistent with the major role of BetS as an emergency system involved in the rapid uptake of betaines in isolated and in planta osmotically stressed bacteroids of S. meliloti.

  16. Effect of the corn silage to grass silage ratio and feed particle size of diets for ruminants on the ruminal Bacteroides-Prevotella community in vitro.

    Science.gov (United States)

    Witzig, M; Boguhn, J; Kleinsteuber, S; Fetzer, I; Rodehutscord, M

    2010-08-01

    This study examined whether different corn silage to grass silage ratios in ruminant rations and different grinding levels of the feed affect the composition of the ruminal Bacteroides-Prevotella community in vitro. Three diets, composed of 10% soybean meal as well as of different corn silage and grass silage proportions, were ground through 1mm or 4mm screened sieves and incubated in a semi-continuous rumen simulation system. On day 14 of the incubation microbes were harvested by centrifugation from the liquid effluent of fermenter vessels. Microbial DNA was extracted for single strand conformation polymorphism (SSCP) analysis of 16S rRNA genes followed by sequencing of single SSCP bands. Fluorescence in situ hybridization (FISH) and real-time quantitative (q) PCR were used to quantify differences in the relative abundance of Bacteroides-Prevotella and Prevotella bryantii. SSCP profiles revealed a significant influence of the forage source as well as of the feed particle size on the community structure of the Bacteroides-Prevotella group. Different, phylogenetically distinct, so far uncultured Prevotella species were detected by sequence analysis of several treatment-dependent occurring SSCP bands indicating different nutritional requirements of these organisms for growth. No quantitative differences in the occurrence of Bacteroides-Prevotella-related species were detected between diets by FISH with probe BAC303. However, real-time qPCR data revealed a higher abundance of P. bryantii with increasing grass silage to corn silage ratio, thus again indicating changes within the community composition of the Bacteroides-Prevotella group. As P. bryantii possesses high proteolytic activity its higher abundance may have been caused by the higher contents of crude protein in the grass silage containing diets. To conclude, results of this study show an influence of the forage source on the ruminal community of Bacteroides-Prevotella. Furthermore, they suggest an effect of

  17. Suppression of colorectal tumorigenesis by recombinant Bacteroides fragilis enterotoxin-2 in vivo

    Science.gov (United States)

    Lv, You; Ye, Tao; Wang, Hui-Peng; Zhao, Jia-Ying; Chen, Wen-Jie; Wang, Xin; Shen, Chen-Xia; Wu, Yi-Bin; Cai, Yuan-Kun

    2017-01-01

    AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dose toxin (ADLT; n = 20, 10 μg), and a model + high-dose toxin (ADHT; n = 20, 20 μg) group. Mice weight, tumor formation and pathology were analyzed. Immunohistochemistry determined Ki-67 and Caspase-3 expression in normal and tumor tissues of colorectal mucosa. RESULTS Recombinant BFT-2 was successfully obtained, along with its biological activity. The most obvious weight loss occurred in the AD group compared with the ADLT group (21.82 ± 0.68 vs 23.23 ± 0.91, P < 0.05) and the ADHT group (21.82 ± 0.68 vs 23.57 ± 1.06, P < 0.05). More tumors were found in the AD group than in the ADLT and ADHT groups (19.75 ± 3.30 vs 6.50 ± 1.73, P < 0.05; 19.75 ± 3.30 vs 6.00 ± 2.16, P < 0.05). Pathology showed that 12 mice had adenocarcinoma and 6 cases had adenoma in the AD group. Five mice had adenocarcinoma and 15 had adenoma in the ADLT group. Four mice had adenocarcinoma and 16 had adenoma in the ADHT group. The incidence of colorectal adenocarcinoma in both the ADHT group and the ADHT group was reduced compared to that in the AD group (P < 0.05, P < 0.05). The positive rate of Ki-67 in the ADLT group and the ADHT group was 50% and 40%, respectively, both of which were lower than that found in the AD group (94.44%, P < 0.05, P < 0.05). Caspase-3 expression in the ADLT group and the ADHT group was 45% and 55%, both of which were higher than that found in the BC group (16.67%, P < 0.05, P < 0.05). CONCLUSION Oral administration with lower-dose biologically active recombinant BFT-2

  18. Bacteroides intestinalis DSM 17393, a member of the human colonic microbiome, upregulates multiple endoxylanases during growth on xylan

    Science.gov (United States)

    Wang, Kui; Pereira, Gabriel V.; Cavalcante, Janaina J. V.; Zhang, Meiling; Mackie, Roderick; Cann, Isaac

    2016-01-01

    Many human diets contain arabinoxylan, and the ease of genome sequencing coupled with reduced cost have led to unraveling the arsenal of genes utilized by the colonic Bacteroidetes to depolymerize this polysaccharide. The colonic Bacteroidetes with potential to ferment arabinoxylans include Bacteroides intestinalis. In this study, we analyzed the hydrolytic activities of members of a xylan degradation cluster encoded on the genome of Bacteroides intestinalis DSM 17393. Here, it is demonstrated that a cocktail of the xylanolytic enzymes completely hydrolyze arabinoxylans found in human diets. We show that this bacterium and relatives have evolved and secrete a unique bifunctional endoxylanase/arabinofuranosidase in the same polypeptide. The bifunctional enzyme and other secreted enzymes attack the polysaccharides extracellularly to remove the side-chains, exposing the xylan backbone for cleavage to xylo-oligosaccharides and xylose. These end products are transported into the cell where a β-xylosidase cleaves the oligosaccharides to fermentable sugars. While our experiments focused on B. intestinalis, it is likely that the extracellular enzymes also release nutrients to members of the colonic microbial community that practice cross-feeding. The presence of the genes characterized in this study in other colonic Bacteroidetes suggests a conserved strategy for energy acquisition from arabinoxylan, a component of human diets. PMID:27681607

  19. Bacteroides isolated from four mammalian hosts lack host-specific 16S rRNA gene phylogeny and carbon and nitrogen utilization patterns.

    Science.gov (United States)

    Atherly, Todd; Ziemer, Cherie J

    2014-04-01

    One-hundred-and-three isolates of Bacteroides ovatus, B. thetaiotaomicron, and B. xylanisolvens were recovered from cow, goat, human, and pig fecal enrichments with cellulose or xylan/pectin. Isolates were compared using 16S rRNA gene sequencing, repetitive sequence-based polymerase chain reaction (rep-PCR), and phenotypic microarrays. Analysis of 16S rRNA gene sequences revealed high sequence identity in these Bacteroides; with distinct phylogenetic groupings by bacterial species but not host origin. Phenotypic microarray analysis demonstrated these Bacteroides shared the ability to utilize many of the same carbon substrates, without differences due to species or host origin, indicative of their broad carbohydrate fermentation abilities. Limited nitrogen substrates were utilized; in addition to ammonia, guanine, and xanthine, purine derivatives were utilized by most isolates followed by a few amino sugars. Only rep-PCR analysis demonstrated host-specific patterns, indicating that genomic changes due to coevolution with host did not occur by mutation in the 16S rRNA gene or by a gain or loss of carbohydrate utilization genes within these Bacteroides. This is the first report to indicate that host-associated genomic differences are outside of 16S rRNA gene and carbohydrate utilization genes and suggest conservation of specific bacterial species with the same functionality across mammalian hosts for this Bacteroidetes clade.

  20. Probabilistic analysis showing that a combination of bacteroides and methanobrevibacter source tracking markers is effective for identifying waters contaminated by human fecal pollution

    Science.gov (United States)

    Johnston, Christopher; Byappanahalli, Muruleedhara N.; Gibson, Jacqueline MacDonald; Ufnar, Jennifer A.; Whitman, Richard L.; Stewart, Jill R.

    2013-01-01

    Microbial source tracking assays to identify sources of waterborne contamination typically target genetic markers of host-specific microorganisms. However, no bacterial marker has been shown to be 100% host-specific, and cross-reactivity has been noted in studies evaluating known source samples. Using 485 challenge samples from 20 different human and animal fecal sources, this study evaluated microbial source tracking markers including the Bacteroides HF183 16S rRNA, M. smithii nifH, and Enterococcus esp gene targets that have been proposed as potential indicators of human fecal contamination. Bayes' Theorem was used to calculate the conditional probability that these markers or a combination of markers can correctly identify human sources of fecal pollution. All three human-associated markers were detected in 100% of the sewage samples analyzed. Bacteroides HF183 was the most effective marker for determining whether contamination was specifically from a human source, and greater than 98% certainty that contamination was from a human source was shown when both Bacteroides HF183 and M. smithii nifH markers were present. A high degree of certainty was attained even in cases where the prior probability of human fecal contamination was as low as 8.5%. The combination of Bacteroides HF183 and M. smithii nifH source tracking markers can help identify surface waters impacted by human fecal contamination, information useful for prioritizing restoration activities or assessing health risks from exposure to contaminated waters.

  1. Nitrogen Fixation (C(2)H(2) Reduction) by Broad Bean (Vicia faba L.) Nodules and Bacteroids under Water-Restricted Conditions.

    Science.gov (United States)

    Guerin, V; Trinchant, J C; Rigaud, J

    1990-03-01

    Water potentials of leaves and nodules of broad bean (Vicia faba L.) cultivated on a sandy mixture were linearly and highly (r(2) = 0.99) correlated throughout a water deprivation of plants. A decrease of 0.2 megapascal of the nodule water potential (Psi(nod)) induced an immediate 25% inhibition of the highest level of acetylene reduction of broad bean nodules attached to roots. This activity continued to be depressed when water stress increased, but the effect was less pronounced. Partial recovery of optimal C(2)H(2) reduction capacity of mildly water stressed nodules (Psi(nod) = -1.2 megapascals) was possible by increasing the external O(2) partial pressure up to 60 kilopascals. The dense packing of the cortical cells of nodules may be responsible for the limitation of O(2) diffusion to the central tissue. Bacteroids isolated from broad bean nodules exhibited higher N(2) fixation activity with glucose than with succinate as an energy-yielding substrate. Bacteroids from stressed nodules appeared more sensitive to O(2), and their optimal activity declined with increasing nodule water deprivation. This effect could be partly due to decreased bacteroid respiration capacity with water stress. Water stress was also responsible for a decrease of the cytosolic protein content of the nodule and more specifically of leghemoglobin. The alteration of the bacteroid environment appears to contribute to the decline in N(2) fixation under water restricted conditions.

  2. High-resolution transcriptomic analyses of Sinorhizobium sp. NGR234 bacteroids in determinate nodules of Vigna unguiculata and indeterminate nodules of Leucaena leucocephala.

    Science.gov (United States)

    Li, Yan; Tian, Chang Fu; Chen, Wen Feng; Wang, Lei; Sui, Xin Hua; Chen, Wen Xin

    2013-01-01

    The rhizobium-legume symbiosis is a model system for studying mutualistic interactions between bacteria and eukaryotes. Sinorhizobium sp. NGR234 is distinguished by its ability to form either indeterminate nodules or determinate nodules with diverse legumes. Here, we presented a high-resolution RNA-seq transcriptomic analysis of NGR234 bacteroids in indeterminate nodules of Leucaena leucocephala and determinate nodules of Vigna unguiculata. In contrast to exponentially growing free-living bacteria, non-growing bacteroids from both legumes recruited several common cellular functions such as cbb3 oxidase, thiamine biosynthesis, nitrate reduction pathway (NO-producing), succinate metabolism, PHB (poly-3-hydroxybutyrate) biosynthesis and phosphate/phosphonate transporters. However, different transcription profiles between bacteroids from two legumes were also uncovered for genes involved in the biosynthesis of exopolysaccharides, lipopolysaccharides, T3SS (type three secretion system) and effector proteins, cytochrome bd ubiquinol oxidase, PQQ (pyrroloquinoline quinone), cytochrome c550, pseudoazurin, biotin, phasins and glycolate oxidase, and in the metabolism of glutamate and phenylalanine. Noteworthy were the distinct expression patterns of genes encoding phasins, which are thought to be involved in regulating the surface/volume ratio of PHB granules. These patterns are in good agreement with the observed granule size difference between bacteroids from L. leucocephala and V. unguiculata.

  3. De Novo Alanine Synthesis by Bacteroids of Mesorhizobium loti Is Not Required for Nitrogen Transfer in the Determinate Nodules of Lotus corniculatus

    OpenAIRE

    Kumar, Shalini; Bourdès, Alexandre; Poole, Philip

    2005-01-01

    Deletion of both alanine dehydrogenase genes (aldA) in Mesorhizobium loti resulted in the loss of AldA enzyme activity from cultured bacteria and bacteroids but had no effect on the symbiotic performance of Lotus corniculatus plants. Thus, neither indeterminate pea nodules nor determinate L. corniculatus nodules export alanine as the sole nitrogen secretion product.

  4. De novo alanine synthesis by bacteroids of Mesorhizobium loti is not required for nitrogen transfer in the determinate nodules of Lotus corniculatus.

    Science.gov (United States)

    Kumar, Shalini; Bourdès, Alexandre; Poole, Philip

    2005-08-01

    Deletion of both alanine dehydrogenase genes (aldA) in Mesorhizobium loti resulted in the loss of AldA enzyme activity from cultured bacteria and bacteroids but had no effect on the symbiotic performance of Lotus corniculatus plants. Thus, neither indeterminate pea nodules nor determinate L. corniculatus nodules export alanine as the sole nitrogen secretion product.

  5. Improved Multiplex PCR Using Conserved and Species-Specific 16S rRNA Gene Primers for Simultaneous Detection of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, and Porphyromonas gingivalis

    OpenAIRE

    Tran, Simon Dangtuan; Rudney, Joel. D.

    1999-01-01

    Among putative periodontal pathogens, Actinobacillus actinomycetemcomitans, Bacteroides forsythus, and Porphyromonas gingivalis are most convincingly implicated as etiological agents in periodontitis. Therefore, techniques for detection of those three species would be of value. We previously published a description of a multiplex PCR that detects A. actinomycetemcomitans and P. gingivalis. The present paper presents an improvement on that technique, which now allows more sensitive detection o...

  6. Bacteroides dorei dominates gut microbiome prior to autoimmunity in Finnish children at high risk for type 1 diabetes.

    Directory of Open Access Journals (Sweden)

    Austin G Davis-Richardson

    2014-12-01

    Full Text Available The incidence of the autoimmune disease, type 1 diabetes (T1D, has increased dramatically over the last half century in many developed countries and is particularly high in Finland and other Nordic countries. Along with genetic predisposition, environmental factors are thought to play a critical role in this increase. As with other autoimmune diseases, the gut microbiome is thought to play a potential role in controlling progression to T1D in children with high genetic risk, but we know little about how the gut microbiome develops in children with high genetic risk for T1D. In this study, the early development of the gut microbiomes of 76 children at high genetic risk for T1D was determined using high-throughput 16S rRNA gene sequencing. Stool samples from children born in the same hospital in Turku, Finland were collected at monthly intervals beginning at 4-6 months after birth until 2.2 years of age. Of those 76 children, 29 seroconverted to T1D-related autoimmunity (cases including 22 who later developed T1D, the remaining 47 subjects remained healthy (controls. While several significant compositional differences in low abundant species prior to seroconversion were found, one highly abundant group composed of two closely related species, Bacteroides dorei and Bacteroides vulgatus, was significantly higher in cases compared to controls prior to seroconversion. Metagenomic sequencing of samples high in the abundance of the B. dorei/vulgatus group before seroconversion, as well as longer 16S rRNA sequencing identified this group as Bacteroides dorei. The abundance of B. dorei peaked at 7.6 months in cases, over eight months prior to the appearance of the first islet autoantibody, suggesting that early changes in the microbiome may be useful for predicting T1D autoimmunity in genetically susceptible infants. The cause of increased B. dorei abundance in cases is not known but its timing appears to coincide with the introduction of solid food.

  7. Current Status of Marker Genes of Bacteroides and Related Taxa for Identifying Sewage Pollution in Environmental Waters

    Directory of Open Access Journals (Sweden)

    Warish Ahmed

    2016-05-01

    Full Text Available Microbial source tracking (MST endeavors to determine sources of fecal pollution in environmental waters by capitalizing on the association of certain microorganisms with the gastrointestinal tract and feces of specific animal groups. Several decades of research have shown that bacteria belonging to the gut-associated order Bacteroidales, and particularly the genus Bacteroides, tend to co-evolve with the host, and are, therefore, particularly suitable candidates for MST applications. This review summarizes the current research on MST methods that employ genes belonging to Bacteroidales/Bacteroides as tracers or “markers” of sewage pollution, including known advantages and deficiencies of the many polymerase chain reaction (PCR-based methods that have been published since 2000. Host specificity is a paramount criterion for confidence that detection of a marker is a true indicator of the target host. Host sensitivity, or the prevalence of the marker in feces/waste from the target host, is necessary for confidence that absence of the marker is indicative of the absence of the pollution source. Each of these parameters can vary widely depending on the type of waste assessed and the geographic location. Differential decay characteristics of bacterial targets and their associated DNA contribute to challenges in interpreting MST results in the context of human health risks. The HF183 marker, derived from the 16S rRNA gene of Bacteroides dorei and closely related taxa, has been used for almost two decades in MST studies, and is well characterized regarding host sensitivity and specificity, and in prevalence and concentration in sewage in many countries. Other markers such as HumM2 and HumM3 show promise, but require further performance testing to demonstrate their widespread utility. An important limitation of the one-marker-one-assay approach commonly used for MST is that given the complexities of microbial persistence in environmental waters, and

  8. The type 4 pilin of Moraxella nonliquefaciens exhibits unique similarities with the pilins of Neisseria gonorrhoeae and Dichelobacter (Bacteroides) nodosus.

    Science.gov (United States)

    Tønjum, T; Marrs, C F; Rozsa, F; Bøvre, K

    1991-10-01

    Moraxella nonliquefaciens is a bacterium which is part of the normal flora of the human upper respiratory tract and is an occasional cause of disease. Using a previously cloned type 4 pilin gene (tfpQ) from Moraxella bovis as a hybridization probe, we have cloned an 826 bp Sau3 AI fragment which contains an M. nonliquefaciens type 4 pilin gene (tfpA) from strain NCTC 7784. The pilin gene is expressed in Escherichia coli. We have examined NCTC 7784 and nine other M. nonliquefaciens strains by genomic Southern hybridization using tfpA as a probe, and they all appeared to have more than one pilin gene. While the predicted amino acid sequence of the M. nonliquefaciens tfpA pilin has conserved regions as compared to pilins of M. bovis and M. lacunata, it also shows similarities to both the type 4 pilin of Neisseria gonorrhoeae and the type 4 pilin of Dichelobacter nodosus (formerly Bacteroides nodosus).

  9. Fluorescence studies with malate dehydrogenase from rhizobium japonicum 3I1B-143 bacteroids: a two-tryptophan containing protein

    Science.gov (United States)

    Ghiron, Camillo A.; Eftink, Maurice R.; Waters, James K.; Emerich, David W.

    1990-05-01

    A number of fluorescence studies, both of trp residues and bound NADH, have been reported for porcine MDH. The large number of trp residues (6) complicates the interpretation of some studies. To circumvent this we have performed studies with a two tryptophan (per subunit) MDH from Rhizobium japonicum 311B-143 bacteroids. We have performed phase/modulation fluorescence lifetime measurements, as a function of temperature and added quencher KI, in order to resolved the 1.3 ns (blue) and 6.6 ns (red) contributions from the two classes of trp residues. Anisotropy decay studies have also been performed. The binding of NADH dynamically quenches the fluorescence of both tip residues, but, unlike mammalian cytoplasmic and mitochondrial MDH, there is not a large enhancement in fluorescence of bound NADH upon forming a ternary complex with either tartronic acid or D-malonate.

  10. Bacteroides uniformis is a putative bacterial species associated with the degradation of the isoflavone genistein in human feces.

    Science.gov (United States)

    Renouf, Mathieu; Hendrich, Suzanne

    2011-06-01

    Inter-individual variation in isoflavone absorption depends on gut microbial degradation and affects the efficacy of these compounds. We hypothesized that inter-individual variation in fecal isoflavone disappearance coincided with variation in bacterial species. In vitro anaerobic fecal disappearance of isoflavones was measured from 33 participants by HPLC. Fecal microbial 16S rRNA variable region PCR products were obtained from 4 participants with the greatest and least genistein or glycitein degradation and were subjected to denaturing gradient gel electrophoresis. DNA bands with a homology of 90-95% to Bacteroides uniformis and Faecalibacterium prausnitzii were present in greater intensities in fecal samples showing a genistein disappearance rate constant of 1.47 ± 0.14 h(-1) compared with those with a genistein disappearance rate constant of 0.15 ± 0.03 h(-1) (P < 0.05). Human fecal bacterial species with DNA sequences 90-100% homologous to Tannerella forsythensis and 4 other species were present in greater intensities in fecal samples showing a glycitein disappearance rate constant of 0.57 ± 0.30 h(-1) compared with fecal samples with a glycitein disappearance rate constant of 0.08 ± 0.03 h(-1) (P < 0.05). In high degraders, B. uniformis may be a candidate for genistein degradation and T. forsythensis for glycitein degradation, based on fecal isoflavone degradation in the presence of these species. Bacteroides acidifaciens increased isoflavone disappearance in anaerobic human fecal incubations under nutrient-rich and -depleted conditions, suggesting this species as one responsible for the generally high degradation of isoflavones by humans. These fecal microbes are candidate biomarkers for interindividual variation in isoflavone uptake and efficacy.

  11. Suppurative otitis and ascending meningoencephalitis associated with Bacteroides tectus and Porphyromonas gulae in a captive Parma wallaby (Macropus parma) with toxoplasmosis.

    Science.gov (United States)

    Giannitti, Federico; Schapira, Andrea; Anderson, Mark; Clothier, Kristin

    2014-09-01

    A 6-year-old female Parma wallaby (Macropus parma) at a zoo in California developed acute ataxia and left-sided circling. Despite intensive care, clinical signs progressed to incoordination and prostration, and the animal was euthanized. At necropsy, the left tympanic cavity was filled with homogeneous suppurative exudate that extended into the cranium expanding the meninges and neuroparenchyma in the lateral and ventral aspect of the caudal ipsilateral brainstem and medulla oblongata. Microscopically, the brainstem showed regional severe suppurative meningoencephalitis with large numbers of neutrophils, fewer macrophages, and lymphocytes admixed with fibrin, necrotic cellular debris, hemorrhage, and mineralization, with numerous intralesional Gram-negative bacilli. Bacteroides spp. and Porphyromonas spp. were isolated on anaerobic culture from the meninges, and the bacteria were further characterized by partial 16S ribosomal RNA gene sequencing as Bacteroides tectus and Porphyromonas gulae. Bacterial aerobic culture from the meninges yielded very low numbers of mixed flora and Proteus spp., which were considered contaminants. Culture of Mycoplasma spp. from middle ear and meninges was negative. Additionally, Toxoplasma gondii cysts were detected by immunohistochemistry in the heart and brain, and anti-Toxoplasma antibodies were detected in serum. The genera Bacteroides and Porphyromonas have been associated with oral disease in marsupials; but not with otitis and meningoencephalitis. The results of the present work highlight the importance of performing anaerobic cultures in the diagnostic investigation of cases of suppurative otitis and meningoencephalitis in macropods.

  12. [Use of reactions with Limulus amoebocyte lysate (LAL) to determine biological activity of lipopolysaccharides from reference and clinical strains of the Bacteroides fragilis group].

    Science.gov (United States)

    Rokosz, Alicja; Fiejka, Maria; Górska, Paulina; Aleksandrowicz, Janina; Meisel-Mikołajczyk, Felicja; Łuczak, MirosŁaw

    2002-01-01

    The aim of this study was to determine and compare a biological activity of lipopolysaccharides (LPS) from reference and clinical strains of strictly anaerobic bacteria belonging to the Bacteroides fragilis group (BFG) by means of quantitative, photometric BET (LAL) method with Limulus polyphemus amoebocyte lysate and chromogenic substrate S-2423. Lipopolysaccharides of five BFG species were extracted by Westphal and Jann method (1965) from eight reference and two clinical strains of B. fragilis group. Crude LPS preparations were purified according to the procedure described by Gmeiner (1975) with ultracentrifugation and nuclease treatment. Biological activities of bacterial endotoxins were determined by quantitative BET method with chromogenic substrate S-2423 (ENDOCHROME kit, Charles River Endosafe Ltd., USA). Tests were performed according to the producer's recommendations. E. coli O55:B5 LPS was applied to compare its activity in reaction with LAL reagent with activities of LPS preparations from rods of the Bacteroides genus. Among examined bacterial compounds the most active in BET method was E. coli O55:B5 LPS. Activities of lipopolysaccharides from five species of BFG rods in reaction with Limulus amoebocyte lysate were differentiated. Greater ability to activate LAL proenzyme revealed lipopolysaccharides of these species of the Bacteroides genus, which are important from the clinical point of view--B. fragilis and B. thetaiotaomicron.

  13. Monoclonal antibodies specific for Bacteroides fragilis enterotoxins BFT1 and BFT2 and their use in immunoassays

    Science.gov (United States)

    Kaplan, Paul M.

    2017-01-01

    We have developed 22 mouse IgG1 monoclonal antibodies (mAbs) against Bacteroides fragilis zinc metalloprotease toxins 1 and 2 (BFT1 and BFT2). Mice were immunized with recombinant BFT1 or BFT2 proteins with metalloprotease activity. Eight of the mAbs bind specifically to BFT1. One mAb, 2H6, binds specifically to BFT2. The remaining 13 mAbs bind to both BFT1 and BFT2. The eight BFT1-specific mAbs recognize at least five different epitopes on the toxin. Four of the BFT1-specific mAbs neutralized rBFT1 metalloprotease activity. Only one of these four mAbs, 1D9, neutralizes the cytotoxic effect of BFT1. Here, we describe the development of enzyme-linked immunosorbent assays (ELISAs) to detect BFT1 or BFT2 toxin in an isotype-specific manner. The sandwich ELISAs have a detection limit of 20 to 40 ng/ml when purified recombinant BFT protein is diluted into PBS. The sandwich ELISA can be used to distinguish and quantify levels of rBFT1 and rBFT2 in stool. This ELISA can be an important tool to investigate the association between BFT expression by enterotoxigenic B. fragilis and diseases such as diarrhea, inflammatory bowel disease and colorectal cancer. PMID:28257448

  14. Structures of Bacteroides fragilis uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) acyltransferase (BfLpxA).

    Science.gov (United States)

    Ngo, Alice; Fong, Kai T; Cox, Daniel L; Chen, Xi; Fisher, Andrew J

    2015-05-01

    Uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) acyltransferase (LpxA) catalyzes a reversible reaction for adding an O-acyl group to the GlcNAc in UDP-GlcNAc in the first step of lipid A biosynthesis. Lipid A constitutes a major component of lipopolysaccharides, also referred to as endotoxins, which form the outer monolayer of the outer membrane of Gram-negative bacteria. Ligand-free and UDP-GlcNAc-bound crystal structures of LpxA from Bacteroides fragilis NCTC 9343, the most common pathogenic bacteria found in abdominal abscesses, have been determined and are presented here. The enzyme crystallizes in a cubic space group, with the crystallographic threefold axis generating the biological functional homotrimer and with each monomer forming a nine-rung left-handed β-helical (LβH) fold in the N-terminus followed by an α-helical motif in the C-terminus. The structure is highly similar to LpxA from other organisms. Yet, despite sharing a similar LβH structure with LpxAs from Escherichia coli and others, previously unseen calcium ions are observed on the threefold axis in B. fragilis LpxA to help stabilize the trimeric assembly.

  15. Survey of antimicrobial susceptibility patterns of the bacteria of the Bacteroides fragilis group isolated from the intestinal tract of children

    Directory of Open Access Journals (Sweden)

    Viviane Nakano

    2004-05-01

    Full Text Available The bacteria of the Bacteroides fragilis group are considered important clinical pathogens and they are the most common anaerobes isolated from human endogenous infections. In this study, the susceptibility patterns to antibiotics and metals of 114 species of the B. fragilis group isolated from children with and without diarrhea were determined. Susceptibility was assayed by using an agar dilution method with Wilkins-Chalgren agar. All B. fragilis strains were resistant to lead and nickel, but susceptible to metronidazole and imipenem. beta-lactamase production was detected by using biological and nitrocefin methods, respectively, in 50% and 90.6% of the isolates of children with diarrhea and in 60% and 90% of the isolates of children without diarrhea. Our results show an increase of antibiotics and metals resistance in this microbial group, and a periodic evaluation of the antimicrobial susceptibility is needed. In Brazil, the contamination for antibiotics or metal ions is often observed, and it is suggested an increase the antimicrobial resistance surveillance of this microbial group, mainly those isolated from children's diarrhea.

  16. Analysis of the outer membrane proteome and secretome of Bacteroides fragilis reveals a multiplicity of secretion mechanisms.

    Directory of Open Access Journals (Sweden)

    Marlena M Wilson

    Full Text Available Bacteroides fragilis is a widely distributed member of the human gut microbiome and an opportunistic pathogen. Cell surface molecules produced by this organism likely play important roles in colonization, communication with other microbes, and pathogenicity, but the protein composition of the outer membrane (OM and the mechanisms used to transport polypeptides into the extracellular space are poorly characterized. Here we used LC-MS/MS to analyze the OM proteome and secretome of B. fragilis NCTC 9343 grown under laboratory conditions. Of the 229 OM proteins that we identified, 108 are predicted to be lipoproteins, and 61 are predicted to be TonB-dependent transporters. Based on their proximity to genes encoding TonB-dependent transporters, many of the lipoprotein genes likely encode proteins involved in nutrient or small molecule uptake. Interestingly, protease accessibility and biotinylation experiments indicated that an unusually large fraction of the lipoproteins are cell-surface exposed. We also identified three proteins that are members of a novel family of autotransporters, multiple potential type I protein secretion systems, and proteins that appear to be components of a type VI secretion apparatus. The secretome consisted of lipoproteins and other proteins that might be substrates of the putative type I or type VI secretion systems. Our proteomic studies show that B. fragilis differs considerably from well-studied Gram-negative bacteria such as Escherichia coli in both the spectrum of OM proteins that it produces and the range of secretion strategies that it utilizes.

  17. BacS: an abundant bacteroid protein in Rhizobium etli whose expression ex planta requires nifA.

    Science.gov (United States)

    Jahn, Olivia J; Davila, Guillermo; Romero, David; Noel, K Dale

    2003-01-01

    Rhizobium etli CFN42 bacteroids from bean nodules possessed an abundant 16-kDa protein (BacS) that was found in the membrane pellet after cell disruption. This protein was not detected in bacteria cultured in tryptone-yeast extract. In minimal media, it was produced at low oxygen concentration but not in a mutant whose nifA was disrupted. N-terminal sequencing of the protein led to isolation of a bacS DNA fragment. DNA hybridization and nucleotide sequencing revealed three copies of the bacS gene, all residing on the main symbiotic plasmid of strain CFN42. A stretch of 304 nucleotides, exactly conserved upstream of all three bacS open reading frames, had very close matches with the NifA and sigma 54 consensus binding sequences. The only bacS homology in the genetic sequence databases was to three hypothetical proteins of unknown function, all from rhizobial species. Mutation and genetic complementation indicated that each of the bacS genes gives rise to a BacS polypeptide. Mutants disrupted or deleted in all three genes did not produce the BacS polypeptide but were Nod+ and Fix+ on Phaseolus vulgaris.

  18. Evaluation of a direct fluorescent antibody staining method for rapid identification of members of the bacteroides fragilis group.

    Science.gov (United States)

    DeGirolami, P C; Mepani, C P

    1981-07-01

    A direct fluorescent antibody test kit (Fluorotec-F, Pfizer Inc., New York, New York) designed for rapid identification of members of the Bacteroides fragilis group (BFG) was evaluated. Tested were 228 clinical specimens (144 direct smears of clinical material, 14 smears of positive blood cultures, and 70 smears of colonies isolated from clinical material) and 49 reference strains of anaerobic bacteria, including 23 members of the BFG. Fluorotec-F detected 68 of 69 (98.5%) members of the BFG, including 55 B. fragilis, 12 B. thetaiotaomicron, and two B. ovatus, identified by cultural methods in all clinical specimens. Three specimens that yielded B. uniformis also fluoresced. Three specimens fluoresced but failed to yield members of the BFG or B. uniformis on culture. Of the 49 reference strains tested, all strains of B. fragilis, B. thetaiotaomicron, nd B. uniformis tested were detected by Fluorotec-F, but only five of a total of 14B. vulgatus, B. distasonis, and B. ovatus tested fluoresced. Of the 25 reference strains of anaerobic bacteria not belonging to the BFG, none fluoresced except for two strains of B. eggerthii. Direct fluorescent antibody staining of smears of clinical specimens suitable for anaerobic culture is a valuable tool for rapid detection of B. fragilis infections.

  19. Degradation of Fructans and Production of Propionic Acid by Bacteroides thetaiotaomicron are Enhanced by the Shortage of Amino Acids.

    Science.gov (United States)

    Adamberg, Signe; Tomson, Katrin; Vija, Heiki; Puurand, Marju; Kabanova, Natalja; Visnapuu, Triinu; Jõgi, Eerik; Alamäe, Tiina; Adamberg, Kaarel

    2014-01-01

    Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory) and levan (synthesized using levansucrase from Pseudomonas syringae), two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (degree of polymerization > 3). Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h), followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of d-lactate (82 ± 33 mmol/gDW) occurred in parallel with extensive consumption (up to 17 mmol/gDW) of amino acids, especially Ser, Thr, and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will

  20. Degradation of fructans and production of propionic acid by Bacteroides thetaiotaomicron are enhanced by shortage of amino acids

    Directory of Open Access Journals (Sweden)

    Signe eAdamberg

    2014-12-01

    Full Text Available Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by the catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory and levan (synthesized using levansucrase from Pseudomonas syringae, two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (DP > 3. Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h, followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of D-lactate (82 ± 33 mmol/gDW occurred in parallel with extensive consumption (up to 17 mmol/gDW of amino acids, especially Ser, Thr and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will be studied in

  1. The colitis-associated transcriptional profile of commensal Bacteroides thetaiotaomicron enhances adaptive immune responses to a bacterial antigen.

    Directory of Open Access Journals (Sweden)

    Jonathan J Hansen

    Full Text Available BACKGROUND: Inflammatory bowel diseases (IBD may be caused in part by aberrant immune responses to commensal intestinal microbes including the well-characterized anaerobic gut commensal Bacteroides thetaiotaomicron (B. theta. Healthy, germ-free HLA-B27 transgenic (Tg rats develop chronic colitis when colonized with complex gut commensal bacteria whereas non-transgenic (nTg rats remain disease-free. However, the role of B. theta in causing disease in Tg rats is unknown nor is much known about how gut microbes respond to host inflammation. METHODS: Tg and nTg rats were monoassociated with a human isolate of B. theta. Colonic inflammation was assessed by histologic scoring and tissue pro-inflammatory cytokine measurement. Whole genome transcriptional profiling of B. theta recovered from ceca was performed using custom GeneChips and data analyzed using dChip, Significance Analysis of Microarrays, and Gene Set Enrichment Analysis (GSEA software. Western Blots were used to determine adaptive immune responses to a differentially expressed B. theta gene. RESULTS: B. theta monoassociated Tg rats, but not nTg or germ-free controls, developed chronic colitis. Transcriptional profiles of cecal B. theta were significantly different in Tg vs. nTg rats. GSEA revealed that genes in KEGG canonical pathways involved in bacterial growth and metabolism were downregulated in B. theta from Tg rats with colitis though luminal bacterial concentrations were unaffected. Bacterial genes in the Gene Ontology molecular function "receptor activity", most of which encode nutrient binding proteins, were significantly upregulated in B. theta from Tg rats and include a SusC homolog that induces adaptive immune responses in Tg rats. CONCLUSIONS: B. theta induces colitis in HLA-B27 Tg rats, which is associated with regulation of bacterial genes in metabolic and nutrient binding pathways that may affect host immune responses. These studies of the host-microbial dialogue may lead to

  2. Bacteroides uniformis CECT 7771 ameliorates metabolic and immunological dysfunction in mice with high-fat-diet induced obesity.

    Directory of Open Access Journals (Sweden)

    Paola Gauffin Cano

    Full Text Available BACKGROUND: Associations have been made between obesity and reduced intestinal numbers of members of the phylum Bacteroidetes, but there is no direct evidence of the role these bacteria play in obesity. Herein, the effects of Bacteroides uniformis CECT 7771 on obesity-related metabolic and immune alterations have been evaluated. METHODS AND FINDINGS: Adult (6-8 week male wild-type C57BL-6 mice were fed a standard diet or a high-fat-diet HFD to induce obesity, supplemented or not with B. uniformis CECT 7771 for seven weeks. Animal weight was monitored and histologic, biochemical, immunocompetent cell functions, and features of the faecal microbiota were analysed after intervention. The oral administration of B. uniformis CECT 7771 reduced body weight gain, liver steatosis and liver cholesterol and triglyceride concentrations and increased small adipocyte numbers in HFD-fed mice. The strain also reduced serum cholesterol, triglyceride, glucose, insulin and leptin levels, and improved oral tolerance to glucose in HFD fed mice. The bacterial strain also reduced dietary fat absorption, as indicated by the reduced number of fat micelles detected in enterocytes. Moreover, B. uniformis CECT 7771 improved immune defence mechanisms, impaired in obesity. HFD-induced obesity led to a decrease in TNF-α production by peritoneal macrophages stimulated with LPS, conversely, the administration of B. uniformis CECT 7771 increased TNF-α production and phagocytosis. Administering this strain also increased TNF-α production by dendritic cells (DCs in response to LPS stimulation, which was significantly reduced by HFD. B. uniformis CECT 7771 also restored the capacity of DCs to induce a T-cell proliferation response, which was impaired in obese mice. HFD induced marked changes in gut microbiota composition, which were partially restored by the intervention. CONCLUSIONS: Altogether, the findings indicate that administration of B. uniformis CECT 7771 ameliorates HFD

  3. Determination of thermodynamic parameters of benzylpenicillin hydrolysis by metallo-β-lactamase CcrA from Bacteroides fragilis

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Le; Zhou, Li-Sheng; Liu, Cheng-Cheng; Shi, Ying; Zhou, Ya-Jun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China); Yang, Ke-Wu, E-mail: kwyang@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China)

    2013-03-20

    Highlights: ► First report the thermokinetic parameters of benzylpenicillin hydrolysis with CcrA. ► The hydrolysis is a spontaneous and exothermic reaction with order of 1.4. ► Summarized that CcrA prefer to hydrolyze penicillins among β-lactam antibiotics. - Abstract: One of the most common way that bacteria become resistant to antibiotics is by the production of metallo-β-lactamases (MβLs) to hydrolyze the β-lactam-containing antibiotics. In this paper, the thermodynamic parameters of benzylpenicillin hydrolysis with B1 subclasses MβL CcrA (carbapenem and cephamycin resistance) from Bacteroides fragilis were determined by microcalorimetry. The activation free energy ΔG{sub ≠}{sup θ} is 87.90 ± 0.03, 88.99 ± 0.01, 89.93 ± 0.04 and 90.93 ± 0.05 kJ mol{sup −1} at 293.15, 298.15, 303.15 and 308.15 K, activation enthalpy ΔH{sub ≠}{sup θ} is 29.21 ± 0.03 kJ mol{sup −1}, activation entropy ΔS{sub ≠}{sup θ} is −200.34 ± 0.08 J mol{sup −1} K{sup −1}, the reaction order is 1.4, and the apparent activation energy E is 31.71 kJ mol{sup −1}. The thermodynamic characterization indicated that CcrA prefer to hydrolyze penicillins among three kinds of β-lactam-containing antibiotics.

  4. Structure of the GH76 α-mannanase homolog, BT2949, from the gut symbiont Bacteroides thetaiotaomicron

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Andrew J. [University of York, Heslington, York YO10 5DD (United Kingdom); Cuskin, Fiona [Newcastle University, Newcastle upon Tyne NE2 4HH (United Kingdom); Spears, Richard J.; Dabin, Jerome; Turkenburg, Johan P. [University of York, Heslington, York YO10 5DD (United Kingdom); Gilbert, Harry J., E-mail: harry.gilbert@newcastle.ac.uk [Newcastle University, Newcastle upon Tyne NE2 4HH (United Kingdom); Davies, Gideon J., E-mail: harry.gilbert@newcastle.ac.uk [University of York, Heslington, York YO10 5DD (United Kingdom)

    2015-02-01

    A high-resolution structure of a noncanonical α-mannanase relevant to human health and nutrition has been solved via heavy-atom phasing of a selenomethionine derivative. The large bowel microbiota, a complex ecosystem resident within the gastrointestinal tract of all human beings and large mammals, functions as an essential, nonsomatic metabolic organ, hydrolysing complex dietary polysaccharides and modulating the host immune system to adequately tolerate ingested antigens. A significant member of this community, Bacteroides thetaiotaomicron, has evolved a complex system for sensing and processing a wide variety of natural glycoproducts in such a way as to provide maximum benefit to itself, the wider microbial community and the host. The immense ability of B. thetaiotaomicron as a ‘glycan specialist’ resides in its enormous array of carbohydrate-active enzymes, many of which are arranged into polysaccharide-utilization loci (PULs) that are able to degrade sugar polymers that are often inaccessible to other gut residents, notably α-mannan. The B. thetaiotaomicron genome encodes ten putative α-mannanases spread across various PULs; however, little is known about the activity of these enzymes or the wider implications of α-mannan metabolism for the health of both the microbiota and the host. In this study, SAD phasing of a selenomethionine derivative has been used to investigate the structure of one such B. thetaiotaomicron enzyme, BT2949, which belongs to the GH76 family of α-mannanases. BT2949 presents a classical (α/α){sub 6}-barrel structure comprising a large extended surface cleft common to other GH76 family members. Analysis of the structure in conjunction with sequence alignments reveals the likely location of the catalytic active site of this noncanonical GH76.

  5. Distinct interactions with cellular E-cadherin of the two virulent metalloproteinases encoded by a Bacteroides fragilis pathogenicity island.

    Science.gov (United States)

    Remacle, Albert G; Shiryaev, Sergey A; Strongin, Alex Y

    2014-01-01

    Bacteroides fragilis causes the majority of Gram-negative anaerobic infections in the humans. The presence of a short, 6-kb, pathogenicity island in the genome is linked to enterotoxigenic B. fragilis (ETBF). The role of the enterotoxin in B. fragilis virulence, however, remains to be determined, as the majority of clinical isolates lack ETBF genes and healthy individuals carry enterotoxin-positive B. fragilis. The island encodes secretory metalloproteinase II (MPII) and one of three homologous enterotoxigenic fragilysin isoenzymes (FRA; also termed B. fragilis toxin or BFT). The secretory metalloproteinases expressed from the genes on the B. fragilis pathogenicity island may have pathological importance within the gut, not linked to diarrhea. MPII and FRA are counter-transcribed in the bacterial genome, implying that regardless of their structural similarity and overlapping cleavage preferences these proteases perform distinct and highly specialized functions in the course of B. fragilis infection. The earlier data by us and others have demonstrated that FRA cleaves cellular E-cadherin, an important adherens junction protein, and weakens cell-to-cell contacts. Using E-cadherin-positive and E-cadherin-deficient cancer cells, and the immunostaining, direct cell binding and pull-down approaches, we, however, demonstrated that MPII via its catalytic domain efficiently binds, rather than cleaves, E-cadherin. According to our results, E-cadherin is an adherens junction cellular receptor, rather than a proteolytic target, of the B. fragilis secretory MPII enzyme. As a result of the combined FRA and MPII proteolysis, cell-to-cell contacts and adherens junctions are likely to weaken further.

  6. Update on resistance of Bacteroides fragilis group and related species with special attention to carbapenems 2006-2009.

    Science.gov (United States)

    Snydman, D R; Jacobus, N V; McDermott, L A; Golan, Y; Goldstein, E J C; Harrell, L; Jenkins, S; Newton, D; Pierson, C; Rosenblatt, J; Venezia, R; Gorbach, S L; Queenan, A M; Hecht, D W

    2011-08-01

    The susceptibility trends for the species of the Bacteroides fragilis group against various antibiotics were determined using data from 4 years [2006-2009] on 1957 isolates referred by 8 medical centers participating in a National Survey for the Susceptibility of B. fragilis. The antibiotic test panel included doripenem, ertapenem, imipenem, meropenem, ampicillin:sulbactam, piperacillin:tazobactam, cefoxitin, clindamycin, moxifloxacin, tigecycline, chloramphenicol and metronidazole. MICs were determined using agar dilution methods following CLSI recommendations. Genetic analysis of isolates from 2008 with elevated MICs (>2 μg/mL) to one or more of the carbapenems to detect presence of the cfiA gene was performed using PCR methodology. The results showed an increase in the resistance rates to the β-lactam antibiotics. High resistance rates were seen for clindamycin and moxifloxacin (as high as 60% for clindamycin and >80% for moxifloxacin), with relatively stable low resistance (5.4%) for tigecycline. For carbapenems, resistance in B. fragilis was 1.1%-2.5% in 2008-9. One isolate resistant to metronidazole (MIC 32 μg/mL) was observed as well as isolates with elevated MICs to chloramphenicol (16 μg/mL). Genetic analysis indicated that the cfiA gene was present in some but not all of the isolates with high MICs to the carbapenems. These data indicate that there continue to be changes in susceptibility over time, and that resistance can be seen among the carbapenems. High antibiotic resistance rates tend to be associated with specific species.

  7. Pglyrp-Regulated Gut Microflora Prevotella falsenii, Parabacteroides distasonis and Bacteroides eggerthii Enhance and Alistipes finegoldii Attenuates Colitis in Mice.

    Science.gov (United States)

    Dziarski, Roman; Park, Shin Yong; Kashyap, Des Raj; Dowd, Scot E; Gupta, Dipika

    2016-01-01

    Dysbiosis is a hallmark of inflammatory bowel disease (IBD), but it is unclear which specific intestinal bacteria predispose to and which protect from IBD and how they are regulated. Peptidoglycan recognition proteins (Pglyrps) are antibacterial, participate in maintaining intestinal microflora, and modulate inflammatory responses. Mice deficient in any one of the four Pglyrp genes are more sensitive to dextran sulfate sodium (DSS)-induced colitis, and stools from Pglyrp-deficient mice transferred to wild type (WT) germ-free mice predispose them to much more severe colitis than stools from WT mice. However, the identities of these Pglyrp-regulated bacteria that predispose Pglyrp-deficient mice to colitis or protect WT mice from colitis are not known. Here we identified significant changes in β-diversity of stool bacteria in Pglyrp-deficient mice compared with WT mice. The most consistent changes in microbiome in all Pglyrp-deficient mice were in Bacteroidales, from which we selected four species, two with increased abundance (Prevotella falsenii and Parabacteroides distasonis) and two with decreased abundance (Bacteroides eggerthii and Alistipes finegoldii). We then gavaged WT mice with stock type strains of these species to test the hypothesis that they predispose to or protect from DSS-induced colitis. P. falsenii, P. distasonis, and B. eggerthii all enhanced DSS-induced colitis in both WT mice with otherwise undisturbed intestinal microflora and in WT mice with antibiotic-depleted intestinal microflora. By contrast, A. finegoldii (which is the most abundant species in WT mice) attenuated DSS-induced colitis both in WT mice with otherwise undisturbed intestinal microflora and in WT mice with antibiotic-depleted intestinal microflora, similar to the colitis protective effect of the entire normal microflora. These results identify P. falsenii, P. distasonis, and B. eggerthii as colitis-promoting species and A. finegoldii as colitis-protective species.

  8. Microbial enterotypes, inferred by the prevotella-to-bacteroides ratio, remained stable during a 6-month randomized controlled diet intervention with the new nordic diet

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Licht, Tine Rask; Poulsen, Sanne;

    2014-01-01

    with central obesity and components of metabolic syndrome could be grouped into two discrete groups simply by their relative abundance of Prevotella spp. divided by Bacteroides spp. (P/B ratio) obtained by quantitative PCR analysis. Furthermore, we showed that these groups remained stable during a 6-month......, controlled dietary intervention, where the effect of consuming a diet in accord with the new Nordic diet (NND) recommendations as opposed to consuming the average Danish diet (ADD) on the gut microbiota was investigated. In this study, subjects (with and without stratification according to P/B ratio) did...

  9. Novel Approach for Evaluation of Bacteroides fragilis Protective Role against Bartonella henselae Liver Damage in Immunocompromised Murine Model

    Science.gov (United States)

    Pagliuca, Chiara; Cicatiello, Annunziata G.; Colicchio, Roberta; Greco, Adelaide; Cerciello, Raimondo; Auletta, Luigi; Albanese, Sandra; Scaglione, Elena; Pagliarulo, Caterina; Pastore, Gabiria; Mansueto, Gelsomina; Brunetti, Arturo; Avallone, Bice; Salvatore, Paola

    2016-01-01

    Bartonella henselae is a gram-negative facultative intracellular bacterium and is the causative agent of cat-scratch disease. Our previous data have established that Bacteroides fragilis colonization is able to prevent B. henselae damages through the polysaccharide A (PSA) in an experimental murine model. In order to determine whether the PSA is essential for the protection against pathogenic effects of B. henselae in immunocompromised hosts, SCID mice were co-infected with B. fragilis wild type or its mutant B. fragilis ΔPSA and the effects of infection on murine tissues have been observed by High-Frequency Ultrasound (HFUS), histopathological examination, and Transmission Electron Microscopy (TEM). For the first time, echostructure, hepatic lobes length, vascular alterations, and indirect signs of hepatic dysfunctions, routinely used as signs of disease in humans, have been analyzed in an immunocompromised murine model. Our findings showed echostructural alterations in all infected mice compared with the Phosphate Buffer Solution (PBS) control group; further, those infected with B. henselae and co-infected with B. henselae/B. fragilis ΔPSA presented the major echostructural alterations. Half of the mice infected with B. henselae and all those co-infected with B. henselae/B. fragilis ΔPSA have showed an altered hepatic echogenicity compared with the renal cortex. The echogenicity score of co-infected mice with B. henselae/B. fragilis ΔPSA differed significantly compared with the PBS control group (p < 0.05). Moreover the inflammation score of the histopathological evaluation was fairly concordant with ultrasound findings. Ultrastructural analysis performed by TEM revealed no significant alterations in liver samples of SCID mice infected with B. fragilis wild type while those infected with B. fragilis ΔPSA showed the presence of collagen around the main vessels compared with the PBS control group. The liver samples of mice infected with B. henselae showed

  10. Infection with bacteroides thetaiotaomicron during posterior decompression and dynamic stabilization of the lumbar spine: a case report and review of the literature.

    Science.gov (United States)

    Agarwal, Nitin; Hansberry, David R; Goldstein, Ira M

    2014-08-01

    Patient and surgical risk factors have often been implicated for postoperative posterior spinal wound infection. A 56-year-old male with widely disseminated multiple myeloma presented with severe back pain and lower extremity weakness as a result of fracture and collapse of the L4 vertebral body. Posterior decompression involving bilateral pedicle resection and partial L4 corpectomy was performed. Stabilization was performed by Dynesys instrumentation of L3-5, screw supplementation with polymethylmethacrylate, and posterolateral fusion was performed. Postoperatively, the patient suffered from multiple infections, including Bacteroides thetaiotaomicron, which were eventually resolved with antibiotic as well as incision and debridement treatment regimens. In cases with numerous perioperative risk factors for infections, the best therapeutic approach may be a preventative one. An understanding of the relevant risk factors may enable the physician to facilitate a perioperative condition best suited for optimal treatment. A case report of infection with Bacteroides thetaiotaomicron during lumbar decompression and dynamic stabilization as well as a review of the literature regarding infection risk factors are presented.

  11. Characterization of the RokA and HexA broad-substrate-specificity hexokinases from Bacteroides fragilis and their role in hexose and N-acetylglucosamine utilization.

    Science.gov (United States)

    Brigham, Christopher J; Malamy, Michael H

    2005-02-01

    Bacteroides fragilis, a human gastrointestinal commensal and an opportunistic pathogen, utilizes simple and complex sugars and polysaccharides for growth in the large intestine and at sites of infection. Because B. fragilis lacks transport-linked sugar phosphorylation systems, cytoplasmic kinase(s) was expected to be required for the phosphorylation of hexoses and hexosamines. We have now identified two hexose kinases that are important for growth of B. fragilis on glucose, mannose, and other sugars. One kinase (RokA), a member of the ROK family of proteins, was found to be the sole kinase for activation of N-acetyl-D-glucosamine (NAG). The other kinase (HexA) is responsible for the majority of the glucose kinase activity in the cell, although a hexA deletion mutant strain was not defective for growth on any substrate tested. Deletion of both the rokA and hexA kinase genes resulted in inability of the cell to use glucose, mannose, NAG, and many other sugars. We purified RokA and determined its approximate molecular mass to be 36.5 kDa. The purified RokA protein was shown to phosphorylate several substrates, including glucose, NAG, and mannose, but not N-acetylmannosamine or N-acetylneuraminic acid. Phylogenetic analysis of RokA showed that it is most similar to kinases from the Cytophaga-Flavibacterium-Bacteroides group, while HexA was most similar to other bacterial hexokinases and eukaryotic hexokinases.

  12. A Highly Active Endo-Levanase BT1760 of a Dominant Mammalian Gut Commensal Bacteroides thetaiotaomicron Cleaves Not Only Various Bacterial Levans, but Also Levan of Timothy Grass

    Science.gov (United States)

    Vija, Heiki; Aasamets, Anneli; Viigand, Katrin

    2017-01-01

    Bacteroides thetaiotaomicron, an abundant commensal of the human gut, degrades numerous complex carbohydrates. Recently, it was reported to grow on a β-2,6-linked polyfructan levan produced by Zymomonas mobilis degrading the polymer into fructooligosaccharides (FOS) with a cell surface bound endo-levanase BT1760. The FOS are consumed by B. thetaiotaomicron, but also by other gut bacteria, including health-promoting bifidobacteria and lactobacilli. Here we characterize biochemical properties of BT1760, including the activity of BT1760 on six bacterial levans synthesized by the levansucrase Lsc3 of Pseudomonas syringae pv. tomato, its mutant Asp300Asn, levansucrases of Zymomonas mobilis, Erwinia herbicola, Halomonas smyrnensis as well as on levan isolated from timothy grass. For the first time a plant levan is shown as a perfect substrate for an endo-fructanase of a human gut bacterium. BT1760 degraded levans to FOS with degree of polymerization from 2 to 13. At optimal reaction conditions up to 1 g of FOS were produced per 1 mg of BT1760 protein. Low molecular weight (prebiotic fiber for B. thetaiotaomicron and contribute to short-chain fatty acids synthesis by gut microbiota. In the genome of Bacteroides xylanisolvens of human origin a putative levan degradation locus was disclosed. PMID:28103254

  13. Scientific Opinion on the safety of ‘heat-treated milk products fermented with Bacteroides xylanisolvens DSM 23964’ as a novel food

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following a request from the European Commission, the EFSA NDA Panel was asked to carry out the additional assessment for ‘pasteurised milk products fermented with Bacteroides xylanisolvens DSM 23964’ as a novel food (NF) in the context of Regulation (EC) No 258/97. Pasteurised or ultra-high-temp......Following a request from the European Commission, the EFSA NDA Panel was asked to carry out the additional assessment for ‘pasteurised milk products fermented with Bacteroides xylanisolvens DSM 23964’ as a novel food (NF) in the context of Regulation (EC) No 258/97. Pasteurised or ultra......-high-temperature-treated milk is used for the fermentation process with B. xylanisolvens DSM 23964. After fermentation the product is heat treated for one hour at 75 °C to ensure the absence of viable B. xylanisolvens DSM 23964. The Panel considers the information provided on the identity and characterisation of B....... xylanisolvens DSM 23964 to be sufficient. The production process encompasses standard techniques used by the dairy industry, is sufficiently described by the applicant and does not give rise to safety concerns. The Panel considers that the information provided on the production process and on the content...

  14. In vitro activity of trovafloxacin against Bacteroides fragilis in mixed culture with either Escherichia coli or a vancomycin- resistant strain of Enterococcus faecium determined by an anaerobic time-kill technique.

    NARCIS (Netherlands)

    L.E.T. Stearne (Lorna); C. Kooi; W.H.F. Goessens (Wil); I.A.J.M. Bakker-Woudenberg (Irma); I.C. Gyssens (Inge)

    2001-01-01

    textabstractTo determine the efficacy of trovafloxacin as a possible treatment for intra-abdominal abscesses, we have developed an anaerobic time-kill technique using different inocula to study the in vitro killing of Bacteroides fragilis in pure culture or in mixed cul

  15. [Tracing the Fecal Contamination Sources Based on Bacteroides 16S rRNA PCR- DGGE in Karst Groundwater: Taking Laolongdong Underground River System, Nanshan, Chongqing as an Example].

    Science.gov (United States)

    Zhang, Hong; Jiang, Yong-jun; Zhang, Yuan-zhu; Duan, Yi-fan; Lü, Xian-fu; He, Qiu-fang

    2016-05-15

    Microbial contamination in karst groundwater continually increases and tracing the source researches has become a hot topic for international researchers. In this study, Laolongdong underground river at Nanshan, Chongqing was chosen as an example to adopt filter membrane methods to monitor the fecal microbial contaminations including the total bacterial concentration (TB), the total E. coli concentration (TE), the total fecal coliform (FC) and the total fecal Streptocoocci (FS). Bacteriodes was used as an indicator and PCR-DGGE analysis was used to trace fecal contamination sources in karst groundwater. The results suggested that groundwater in this area was seriously polluted by microbes from feces. The concentrations of microbial parameters exceeded limited levels greatly and the total bacterial amounts ranged 10-2.9 x 10⁷ CFU · mL⁻¹, the concentrations of E. coli were between 4.3-4.0 x 10⁵ CFU · mL⁻¹, the max concentration of FC was 1.1 x 10⁶ CFU · (100 mL)⁻¹ and the max concentration of FS was 1.1 x 10⁵ CFU · (100 mL)⁻¹. The FC/FS ratios were mostly over 2 which suggested that the main fecal source in groundwater was human feces. In addition, PCR-DGGE contrastive analysis of Bacteroides communities showed that the similarities between groundwater samples and human feces were in range of 7. 1% -69. 1% , and the similarity of the groundwater sample from Laolongdong underground river outlet was 69.1% . Bacteroides community similarities between groundwater samples and swine feces were in range of 1.1%-53.4%, and the similarity of Laolongdong underground river outlet was merely 1.5%. The similarity data implied that groundwater contamination resulted mainly from human feces, swine feces contamination composed part of animals' fecal contamination, and other animals' feces participated too. Furthermore, sequencing results of PCR-DGGE products revealed that most Bacteroides in groundwater originated from human intestinal tract and human feces.

  16. Molecular analysis of the carbapenem and metronidazole resistance mechanisms of Bacteroides strains reported in a Europe-wide antibiotic resistance survey.

    Science.gov (United States)

    Sóki, József; Eitel, Zsuzsa; Urbán, Edit; Nagy, Elisabeth

    2013-02-01

    Here we examine the carbapenem and metronidazole resistance mechanisms of 640 Bacteroides strains reported in the 2008-2009 European antibiotic susceptibility survey. Of the 22 strains with elevated imipenem minimum inhibitory concentrations (≥4 μg/mL), 10 were cfiA-positive and out of these 5 carried activating insertion sequence (IS) elements in the upstream regions of the cfiA genes. However, resistant strains with cfiA genes but with no activating IS elements were found (n=2) as well as a resistant strain with no cfiA gene. In the former the resistance phenotypes by Etest were heterogeneous, whilst in the latter no carbapenemase production was seen; both mechanisms have been rarely observed, examined and characterised. Interestingly, few (n=3) nim-positive strains were found, including one metronidazole-resistant strain harbouring nimE activated by ISBf6, and two susceptible strains harbouring chromosomally located nim genes.

  17. Effect of the oral intake of yogurt containing Bifidobacterium longum BB536 on the cell numbers of enterotoxigenic Bacteroides fragilis in microbiota.

    Science.gov (United States)

    Odamaki, Toshitaka; Sugahara, Hirosuke; Yonezawa, Sumiko; Yaeshima, Tomoko; Iwatsuki, Keiji; Tanabe, Soichi; Tominaga, Tomoya; Togashi, Hideo; Benno, Yoshimi; Xiao, Jin-zhong

    2012-02-01

    Enterotoxigenic Bacteroides fragilis (ETBF) strains have been suggested to be associated with acute and persistent diarrheal disease, inflammatory bowel disease and colorectal cancer, although further epidemiological studies are needed for clarification. Here, a pilot study was performed to examine the effect of the oral administration of yogurt supplemented with a probiotic strain on the cell numbers of fecal ETBF in a healthy population. Among 420 healthy adults, 38 subjects were found to be ETBF carriers, giving a prevalence of approximately 9%. Among them, 32 subjects were enrolled in an open, randomized, parallel-group study to ingest yogurt supplemented with a probiotic strain, Bifidobacterium longum BB536 (BB536Y group), for 8 weeks, with milk provided to the control group (milk group). The cell numbers of ETBF and the dominant species of the B. fragilis group were measured by a quantitative PCR method. Compared with the baseline values, there was a significant decrease in the cell number of ETBF at week 8 in the BB536Y group but not in the milk group. Linear mixed models analysis for longitudinal data revealed a significant difference in the changes of ETBF cell number between the two groups during the intervention phase. These results imply the potential of probiotic yogurt for eliminating ETBF in the microbiota, but its clinical significance needs to be evaluated in the future. This is the first report of a possible effect of probiotic intake on ETBF in the microbiota.

  18. Characterization of the first alginolytic operons in a marine bacterium: from their emergence in marine Flavobacteriia to their independent transfers to marine Proteobacteria and human gut Bacteroides.

    Science.gov (United States)

    Thomas, François; Barbeyron, Tristan; Tonon, Thierry; Génicot, Sabine; Czjzek, Mirjam; Michel, Gurvan

    2012-09-01

    Alginate constitutes a significant part of seaweed biomass and thus a crucial nutrient for numerous marine heterotrophic bacteria. However, the mechanisms for alginate assimilation remain largely unknown in marine microorganisms. We show here that the genome of the marine flavobacterium Zobellia galactanivorans contains seven putative alginate lyase genes, five of them localized within two clusters comprising additional carbohydrate-related genes. The transcription of these genes and the alginolytic activity were strongly induced when Z. galactanivorans used alginate as sole carbon source. These clusters were shown to be transcribed as polycistronic mRNAs and thus to constitute operons. Several candidate enzymes were successfully overexpressed in Escherichia coli, purified and their activity tested. Particularly, AlyA1, AlyA4, AlyA5 and AlyA7 are confirmed as active alginate lyases. Zg2622 and Zg2614 are a dehydrogenase and a kinase, respectively, further converting the terminal unsaturated monosaccharides released by alginate lyases into 2-keto-3-deoxy-6-phosphogluconate. In-depth phylogenomic analyses reveal that such alginolytic operons originated from an ancestral marine flavobacterium and were independently transferred to marine proteobacteria and Japanese gut Bacteroides. These bacteria thus gained the capacity to assimilate the main polysaccharide of brown algae, an adaptive advantage in coastal environments but also in the gut microbiota of specific human population.

  19. Coculture fermentations of Bifidobacterium species and Bacteroides thetaiotaomicron reveal a mechanistic insight into the prebiotic effect of inulin-type fructans.

    Science.gov (United States)

    Falony, Gwen; Calmeyn, Thomas; Leroy, Frédéric; De Vuyst, Luc

    2009-04-01

    Four bifidobacteria, each representing a cluster of strains with specific inulin-type-fructan degradation capacities, were grown in coculture fermentations with Bacteroides thetaiotaomicron LMG 11262, a strain able to metabolize both oligofructose and inulin. In a medium for colon bacteria with inulin as the sole added energy source, the ability of the bifidobacteria to compete for this substrate reflected phenotypical variation. Bifidobacterium breve Yakult, a strain that was not able to degrade oligofructose or inulin, was outcompeted by B. thetaiotaomicron LMG 11262. Bifidobacterium adolescentis LMG 10734, a strain that could degrade oligofructose (displaying a preferential breakdown mechanism) but that did not grow on inulin, managed to become competitive when oligofructose and short fractions of inulin started to accumulate in the fermentation medium. Bifidobacterium angulatum LMG 11039(T), a strain that was previously shown to degrade all oligofructose fractions simultaneously and to be able to partially break down inulin, was competitive from the beginning of the fermentation, consuming short fractions of inulin from the moment they appeared. Bifidobacterium longum LMG 11047, representing a cluster of bifidobacteria that shared both high fructose consumption and oligofructose degradation rates and were able to perform partial breakdown of inulin, was the dominating strain in a coculture with B. thetaiotaomicron LMG 11262. These observations indicate that distinct subgroups within the large-intestinal Bifidobacterium population will be stimulated by different groups of prebiotic inulin-type fructans, a variation that could be reflected in differences concerning their health-promoting effects.

  20. Distribution, Detection of Enterotoxigenic Strains and Antimicrobial Drug Susceptibility Patterns of Bacteroides Fragilis Group in Diarrheic and Non-Diarrheic Feces from Brazilian Infants

    Science.gov (United States)

    Ferreira, Débora Paula; Silva, Vânia Lúcia; Guimarães, Danielle Aparecida; Coelho, Cíntia Marques; Zauli, Danielle Alves Gomes; Farias, Luiz Macêdo; Carvalho, Maria Auxiliadora Roque; Diniz, Claudio Galuppo

    2010-01-01

    Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0–5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children. PMID:24031535

  1. Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of bacteroides fragilis group in diarrheic and non-diarrheic feces from brazilian infants.

    Science.gov (United States)

    Ferreira, Débora Paula; Silva, Vânia Lúcia; Guimarães, Danielle Aparecida; Coelho, Cíntia Marques; Zauli, Danielle Alves Gomes; Farias, Luiz Macêdo; Carvalho, Maria Auxiliadora Roque; Diniz, Claudio Galuppo

    2010-07-01

    Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.

  2. The Dysregulation of Polyamine Metabolism in Colorectal Cancer Is Associated with Overexpression of c-Myc and C/EBPβ rather than Enterotoxigenic Bacteroides fragilis Infection

    Directory of Open Access Journals (Sweden)

    Anastasiya V. Snezhkina

    2016-01-01

    Full Text Available Colorectal cancer is one of the most common cancers in the world. It is well known that the chronic inflammation can promote the progression of colorectal cancer (CRC. Recently, a number of studies revealed a potential association between colorectal inflammation, cancer progression, and infection caused by enterotoxigenic Bacteroides fragilis (ETBF. Bacterial enterotoxin activates spermine oxidase (SMO, which produces spermidine and H2O2 as byproducts of polyamine catabolism, which, in turn, enhances inflammation and tissue injury. Using qPCR analysis, we estimated the expression of SMOX gene and ETBF colonization in CRC patients. We found no statistically significant associations between them. Then we selected genes involved in polyamine metabolism, metabolic reprogramming, and inflammation regulation and estimated their expression in CRC. We observed overexpression of SMOX, ODC1, SRM, SMS, MTAP, c-Myc, C/EBPβ (CREBP, and other genes. We found that two mediators of metabolic reprogramming, inflammation, and cell proliferation c-Myc and C/EBPβ may serve as regulators of polyamine metabolism genes (SMOX, AZIN1, MTAP, SRM, ODC1, AMD1, and AGMAT as they are overexpressed in tumors, have binding site according to ENCODE ChIP-Seq data, and demonstrate strong coexpression with their targets. Thus, increased polyamine metabolism in CRC could be driven by c-Myc and C/EBPβ rather than ETBF infection.

  3. Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of Bacteroides fragilis group in diarrheic and non-diarrheic feces from Brazilian infants

    Directory of Open Access Journals (Sweden)

    Débora Paula Ferreira

    2010-10-01

    Full Text Available Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110 and non-diarrheic (n=65 fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic, and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.

  4. The symbiotic bacterial surface factor polysaccharide A on Bacteroides fragilis inhibits IL-1β-induced inflammation in human fetal enterocytes via toll receptors 2 and 4

    Science.gov (United States)

    Jiang, Fei; Meng, Di; Weng, Meiqian; Zhu, Weishu; Wu, Wenxue; Kasper, Dennis; Walker, W. Allan

    2017-01-01

    Colonizing bacteria interacting with the immature, unlike the mature, human intestine favors inflammation over immune homeostasis. As a result, ten percent of premature infants under 1500 grams weight develop an inflammatory necrosis of the intestine after birth, e.g., necrotizing enterocolitis (NEC). NEC is a major health problem in this population causing extensive morbidity and mortality and an enormous expenditure of health care dollars. NEC can be prevented by giving preterm infants their mother’s expressed breast milk or ingesting selective probiotic organisms. Vaginally delivered, breast fed newborns develop health promoting bacteria (“pioneer” bacteria) which preferentially stimulate intestinal host defense and anti-inflammation. One such “pioneer” organism is Bacteroides fragilis with a polysaccharide (PSA) on its capsule. B. fragilis has been shown developmentally in intestinal lymphocytes and dendritic cells to produce a balanced T-helper cell (TH1/TH2) response and to reduce intestinal inflammation by activity through the TLR2 receptor stimulating IL-10 which inhibits IL-17 causing inflammation. No studies have been done on the role of B. fragilis PSA on fetal enterocytes and its increased inflammation. Accordingly, using human and mouse fetal intestinal models, we have shown that B. fragilis with PSA and PSA alone inhibits IL-1β-induced IL-8 inflammation in fetal and NEC intestine. We have also begun to define the mechanism for this unique inflammation noted in fetal intestine. We have shown that B. fragilis PSA anti-inflammation requires both the TLR2 and TLR4 receptor and is in part mediated by the AP1 transcription factor (TLR2) which is developmentally regulated. These observations may help to devise future preventative treatments of premature infants against NEC. PMID:28278201

  5. Scientific Opinion on the safety of ?heat-treated milk products fermented with Bacteroides xylanisolvens DSM 23964? as a novel food

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2015-01-01

    Full Text Available Following a request from the European Commission, the EFSA NDA Panel was asked to carry out the additional assessment for ‘pasteurised milk products fermented with Bacteroides xylanisolvens DSM 23964’ as a novel food (NF in the context of Regulation (EC No 258/97. Pasteurised or ultra-high-temperature-treated milk is used for the fermentation process with B. xylanisolvens DSM 23964. After fermentation the product is heat treated for one hour at 75 °C to ensure the absence of viable B. xylanisolvens DSM 23964. The Panel considers the information provided on the identity and characterisation of B. xylanisolvens DSM 23964 to be sufficient. The production process encompasses standard techniques used by the dairy industry, is sufficiently described by the applicant and does not give rise to safety concerns. The Panel considers that the information provided on the production process and on the content of vitamins B2 and B12 and furosine in heat-treated fermented milk products does not give rise to concerns regarding disadvantageous nutritional effects. The Panel considers that the microbiological data provided do not give rise to safety concerns. The Panel also notes that a pilot study and a RCT over six weeks with 140 volunteers receiving daily doses of a spray-dried heat-treated fermented milk product containing intakes of up to 1 ´ 1012 inactivated bacterial cells of B. xylanisolvens DSM 23964 were provided. No clinical effects related to the treatment were observed in the two studies. Although no information has been provided to conclude on the risk of allergic reactions caused by the NF, the Panel considers that it is unlikely that its allergenic potential is dissimilar to that of other fermented dairy products. The Panel concludes that the NF ‘heat-treated milk products fermented with B. xylanisolvens DSM 23964’ is safe for the proposed uses and at the proposed use levels.

  6. Effects of Diet on Resource Utilization by a Model Human Gut Microbiota Containing Bacteroides cellulosilyticus WH2, a Symbiont with an Extensive Glycobiome

    Energy Technology Data Exchange (ETDEWEB)

    McNulty, Nathan [Washington University, St. Louis; Wu, Meng [Washington University, St. Louis; Erickson, Alison L [ORNL; Pan, Chongle [ORNL; Erickson, Brian K [ORNL; Martens, Eric C [University of Michigan; Pudlo, Nicholas A [University of Michigan; Muegge, Brian [Washington University, St. Louis; Henrissat, Bernard [Universite d' Aix-Marseille I & II; Hettich, Robert {Bob} L [ORNL; Gordon, Jeffrey [Washington University, St. Louis

    2013-01-01

    The human gut microbiota is an important metabolic organ, yet little is known about how its individual species interact, establish dominant positions, and respond to changes in environmental factors such as diet. In this study, gnotobiotic mice were colonized with an artificial microbiota comprising 12 sequenced human gut bacterial species and fed oscillating diets of disparate composition. Rapid, reproducible, and reversible changes in the structure of this assemblage were observed. Time-series microbial RNA-Seq analyses revealed staggered functional responses to diet shifts throughout the assemblage that were heavily focused on carbohydrate and amino acid metabolism. High-resolution shotgun metaproteomics confirmed many of these responses at a protein level. One member, Bacteroides cellulosilyticus WH2, proved exceptionally fit regardless of diet. Its genome encoded more carbohydrate active enzymes than any previously sequenced member of the Bacteroidetes. Transcriptional profiling indicated that B. cellulosilyticus WH2 is an adaptive forager that tailors its versatile carbohydrate utilization strategy to available dietary polysaccharides, with a strong emphasis on plant-derived xylans abundant in dietary staples like cereal grains. Two highly expressed, diet-specific polysaccharide utilization loci (PULs) in B. cellulosilyticus WH2 were identified, one with characteristics of xylan utilization systems. Introduction of a B. cellulosilyticus WH2 library comprising .90,000 isogenic transposon mutants into gnotobiotic mice, along with the other artificial community members, confirmed that these loci represent critical diet-specific fitness determinants. Carbohydrates that trigger dramatic increases in expression of these two loci and many of the organism s 111 other predicted PULs were identified by RNA-Seq during in vitro growth on 31 distinct carbohydrate substrates, allowing us to better interpret in vivo RNA-Seq and proteomics data. These results offer insight

  7. Structures of complexes of a metal-independent glycosyltransferase GT6 from Bacteroides ovatus with UDP-N-acetylgalactosamine (UDP-GalNAc) and its hydrolysis products.

    Science.gov (United States)

    Pham, Tram T K; Stinson, Brittany; Thiyagarajan, Nethaji; Lizotte-Waniewski, Michelle; Brew, Keith; Acharya, K Ravi

    2014-03-21

    Mammalian members of glycosyltransferase family 6 (GT6) of the CAZy database have a GT-A fold containing a conserved Asp-X-Asp (DXD) sequence that binds an essential metal cofactor. Bacteroides ovatus GT6a represents a GT6 clade found in more than 30 Gram-negative bacteria that is similar in sequence to the catalytic domains of mammalian GT6, but has an Asn(95)-Ala-Asn(97) (NXN) sequence substituted for the DXD motif and metal-independent catalytic activity. Co-crystals of a low activity mutant of BoGT6a (E192Q) with UDP-GalNAc contained protein complexes with intact UDP-GalNAc and two forms with hydrolysis products (UDP plus GalNAc) representing an initial closed complex and later open form primed for product release. Two cationic residues near the C terminus of BoGT6a, Lys(231) and Arg(243), interact with the diphosphate moiety of UDP-GalNAc, but only Lys(231) interacts with the UDP product and may function in leaving group stabilization. The amide group of Asn(95), the first Asn of the NXN motif, interacts with the ribose moiety of the substrate. This metal-independent GT6 resembles its metal-dependent homologs in undergoing conformational changes on binding UDP-GalNAc that arise from structuring the C terminus to cover this substrate. It appears that in the GT6 family, the metal cofactor functions specifically in binding the UDP moiety in the donor substrate and transition state, actions that can be efficiently performed by components of the polypeptide chain.

  8. Development of Bacteroides 16S rRNA Gene TaqMan-Based Real-Time PCR Assays for Estimation of Total, Human, and Bovine Fecal Pollution in Water

    Science.gov (United States)

    Layton, Alice; McKay, Larry; Williams, Dan; Garrett, Victoria; Gentry, Randall; Sayler, Gary

    2006-01-01

    Bacteroides species are promising indicators for differentiating livestock and human fecal contamination in water because of their high concentration in feces and potential host specificity. In this study, a real-time PCR assay was designed to target Bacteroides species (AllBac) present in human, cattle, and equine feces. Direct PCR amplification (without DNA extraction) using the AllBac assay was tested on feces diluted in water. Fecal concentrations and threshold cycle were linearly correlated, indicating that the AllBac assay can be used to estimate the total amount of fecal contamination in water. Real-time PCR assays were also designed for bovine-associated (BoBac) and human-associated (HuBac) Bacteroides 16S rRNA genes. Assay specificities were tested using human, bovine, swine, canine, and equine fecal samples. The BoBac assay was specific for bovine fecal samples (100% true-positive identification; 0% false-positive identification). The HuBac assay had a 100% true-positive identification, but it also had a 32% false-positive rate with potential for cross-amplification with swine feces. The assays were tested using creek water samples from three different watersheds. Creek water did not inhibit PCR, and results from the AllBac assay were correlated with those from Escherichia coli concentrations (r2 = 0.85). The percentage of feces attributable to bovine and human sources was determined for each sample by comparing the values obtained from the BoBac and HuBac assays with that from the AllBac assay. These results suggest that real-time PCR assays without DNA extraction can be used to quantify fecal concentrations and provide preliminary fecal source identification in watersheds. PMID:16751534

  9. In Vivo Efficacy of Trovafloxacin against Bacteroides fragilis in Mixed Infection with either Escherichia coli or a Vancomycin-Resistant Strain of Enterococcus faecium in an Established-Abscess Murine Model

    OpenAIRE

    2001-01-01

    The pharmacodynamic and pharmacokinetic properties of trovafloxacin were studied in a standardized murine model of established subcutaneous abscesses. Daily dosing regimens of 37.5 to 300 mg/kg every 8 h (q8h) or every 24 h (q24h) were started 3 days after inoculation with mixtures containing either Bacteroides fragilis-Escherichia coli-autoclaved cecal contents (ACC) or B. fragilis–vancomycin-resistant Enterococcus faecium (VREF)–ACC. Treatment was continued for 3 or 5 days. The efficacy of ...

  10. Levofloxacin plus metronidazole administered once daily versus moxifloxacin monotherapy against a mixed infection of Escherichia coli and Bacteroides fragilis in an in vitro pharmacodynamic model.

    Science.gov (United States)

    Hermsen, Elizabeth D; Hovde, Laurie B; Sprandel, Kelly A; Rodvold, Keith A; Rotschafer, John C

    2005-02-01

    Moxifloxacin has been suggested as an option for monotherapy of intra-abdominal infections. Recent data support the use of a once-daily metronidazole regimen. The purpose of this study was to investigate the activity of levofloxacin (750 mg every 24 h [q24h]) plus metronidazole (1,500 mg q24h) compared with that of moxifloxacin (400 mg q24h) monotherapy in a mixed-infection model. By using an in vitro pharmacodynamic model in duplicate, Escherichia coli and Bacteroides fragilis were exposed to peak concentrations of 8.5 mg of levofloxacin/liter q24h, 32 mg of metronidazole/liter q24h, and 2 mg for moxifloxacin/liter q24h for 24 h. The activities of levofloxacin, metronidazole, moxifloxacin, and levofloxacin plus metronidazole were evaluated against E. coli, B. fragilis, and E. coli plus B. fragilis. The targeted half-lives of levofloxacin, metronidazole, and moxifloxacin were 8, 8, and 12 h, respectively. Time-kill curves were analyzed for time to 3-log killing, slope, and regrowth. Pre- and postexposure MICs were determined. The preexposure levofloxacin, metronidazole, and moxifloxacin MICs for E. coli and B. fragilis were 0.5 and 1, >64 and 0.5, and 1 and 0.25 mg/liter, respectively. Levofloxacin and moxifloxacin achieved a 3-log killing against E. coli and B. fragilis in all experiments, as did metronidazole against B. fragilis. Metronidazole did not decrease the starting inoculum of E. coli. The area under the concentration-time curve/MIC ratios for E. coli and B. fragilis were 171.7 and 85.9, respectively, for levofloxacin and 26 and 103.9, respectively, for moxifloxacin. Levofloxacin plus metronidazole exhibited the fastest rates of killing. The levofloxacin and moxifloxacin MICs for B. fragilis increased 8- to 16-fold after the organism was exposed to moxifloxacin. No other changes in the postexposure MICs were found. Levofloxacin plus metronidazole administered once daily exhibited activity similar to that of moxifloxacin against the mixed E. coli and B

  11. Phenotypic detection of the cfiA metallo-β-lactamase in Bacteroides fragilis with the meropenem-EDTA double-ended Etest and the ROSCO KPC/MBL Confirm Kit

    DEFF Research Database (Denmark)

    Schwensen, Simon A; Acar, Ziyap; Sydenham, Thomas V

    2016-01-01

    OBJECTIVES: To investigate the performance of the meropenem and imipenem double-ended Etest ± EDTA and the tablet-based (meropenem and meropenem + dipicolinic acid) KPC/MBL Confirm Kit to detect cfiA metallo-β-lactamase (MBL) in Bacteroides fragilis. METHODS: Well-characterized B. fragilis isolates......-ended Etest gave an MIC ratio ≥8 (positive test) with all the isolates. All isolates that were meropenem intermediate or resistant had a zone diameter difference ≥6 mm with the KPC/MBL Confirm Kit. CONCLUSIONS: The meropenem double-ended Etest and not imipenem should be preferred for phenotypic detection...... of MBLs in B. fragilis. The KPC/MBL Confirm Kit could be an alternative with isolates that are meropenem intermediate or resistant (MIC >2 mg/L)....

  12. [Tigecycline: CMI 50/90 towards 1766 Gram-negative bacilli (3rd generation cephalosporins resistant enterobacteriaceae), Acinetobacter baumannii and Bacteroides fragilis group, University Hospital - Montpellier, 2008-2011].

    Science.gov (United States)

    Froment Gomis, P; Jean-Pierre, H; Rousseau-Didelot, M-N; Compan, B; Michon, A-L; Godreuil, S

    2013-12-01

    Tigecycline is a new glycylcyclin with a wide spectre including multi-resistant bacteria. Our laboratory tests in routine the in vitro activity of the TGC towards clinically significant isolates of 3rd generation cephalosporins resistant enterobacteriaceae (EC3R), Acinetobacter baumannii and Bacteroides fragilis group (BFG). The objective of this study is to describe the in vitro activity of TGC against these strains isolated between 2008 and 2011 in the university hospital of Montpellier. In this study period, 1070 isolates EC3R including 541 extended spectrum β-lactamase-producers (ESBL) strains, 47 isolates of A. baumannii including 40 multi-resistant isolates and 645 isolates of BFG were tested. Minimum inhibitory concentrations (MIC) were determined using the E-test method. TGC was active against 86.2% of EC3R with a MIC 90 less or equal to 1mg/L (Escherichia coli being the most sensitive species). A. baumannii and BFG were also inhibited at low concentrations of TGC with a MIC 90 less or equal to 2mg/L respectively for 47% and 84.2% of the isolates. Our study confirms the activity of TGC against the EC3R including ESBL-producers strains. The relevance of the therapeutic use of TGC on the BFG isolates with a MIC greater than 2mg/L should be better documented. Often prescribed in therapeutic impasse, the proper use of TGC would require: clarifying the threshold of sensitivity for some species (i.e., A. baumannii, Bacteroides fragilis group); a better understanding of correlation between in vitro and in vivo activity.

  13. THE PCR DETECTION AND CLINIC SIGNIFICANCE ABOUT BACTEROIDES FORSYTHUS IN THE PATIENTS WITH PERI-IMPLANTITIS%种植体周围袋中福赛类杆菌的PCR检测及临床意义

    Institute of Scientific and Technical Information of China (English)

    王海涛; 隋素琴; 白燕; 张晓敏; 杨慧; 曹庆堂

    2012-01-01

    Objective: we can provide the basis for evaluation in peri - implantitis diagnosis and treatment through exploring the peri - implant pathogenesis and analysing the distribution prevalance and content of Bacteroides forsythus (B. f) in peri - implantitis patients . chronic periodontitis patients and periodontally healthy adults. Method: Subgingival plaque samples were collected from 56 peri -implantitis patients,60 chronic periodontitis patients and 58 periodontally healthy adults. Bacteroides forsythus were detected by 16S rRNA polymerase chain reaction. Results:The prevalance of B. f differed significantly in patients with peri - implantitis, patients with chronic periodontitis and periodontally healthy adults( P 0.05). Ct of B. f in peri - im-plantitis is higher than chronic periodontitis (P <0.05). Conclusion: These results indicate a possible association between chronical periodontal disease,chronical peri -implantitis disease and content of B. f, Implant denture need more special maintenance.%目的:探讨福赛类杆菌在牙周健康者龈沟液中、慢性牙周炎病人牙周袋内、种植体周围炎病人种植周围袋内的含量及其与感染发生的关系.方法:收集58名牙周健康者、60例慢性牙周炎病人、56例慢性种植体周围炎病人龈下菌斑,采用免疫荧光定量16S RNA PCR方法检测福赛类杆菌的含量与分布.结果 牙周健康者龈沟内福赛类杆菌的检出率为8.62%,平均Ct值为0.0122±0.0000;慢性牙周炎病人龈下菌斑福赛类杆菌的检出率为81.67%,平均Ct值为0.0356±0.0018;慢性种植体周围炎病人龈下菌斑赛类杆菌的检出率为85.71%,平均Ct值为0.0563±0.0021.结论:种植体周围炎、慢性牙周炎的发生与福赛类杆菌的感染有相关性,种植体周围炎、慢性牙周炎的发病机理可能相一致.

  14. 肉桂水提物对大鼠肠道梭菌属IV簇细菌和拟杆菌的影响%Effect of aqueous Cinnamomum cassia extracts on gastrointestinal Clostridium cluster IV and Bacteroides in rats

    Institute of Scientific and Technical Information of China (English)

    黄丽珠; 詹宏林; 王聪; 彭喜春; 张宁; 刘柳

    2012-01-01

    目的:肉桂水提物对大鼠结肠和直肠梭菌属IV簇和拟杆菌的影响。方法:给SD大鼠灌胃一个月后分别取结肠和直肠内容物,针对肠道梭菌属IV簇和拟杆菌的16SrRNA基因应用末端限制性片段多态性分析技术对这两类菌的多样性及分布进行分析。结果:研究发现肉桂水提物能降低梭菌属IV簇细菌在结肠和直肠中的数量,增加拟杆菌属细菌在结肠和直肠中的数量;该水提物对结肠和直肠的结构均产生影响,但影响并不相同,其中对直肠的影响更大。结论:肉桂水提物对大鼠肠道菌群的这种影响可能与肉桂治疗肥胖和糖尿病有功效有关。%Objective:To explore the impact of aqueous Cinnamomum cassia(C.cassia) extracts on gut microbiota.Methods:The colon and rectal contents were sampled after rats had been orally administrated the aqueous extracts for one month.Clostridium cluster IV and Bacteroides in the samples were analyzed by the terminal restriction fragment length polymorphism(tRFLP) method based on the bacterial 16S rRNA gene and nucleotide sequencing.Result:The aqueous C.cassia extracts could down-regulate the amount of microbiota of Clostridium cluster IV in rat gut,along with the increase of microbiota of Bacteroides.Various effects were exerted by the extracts on microbiota in colon and rectum,and the impact presented heavier in rectum.Conclusion:These variations of rat gut microbiota induced by the aqueous C.cassia extracts may reflect the functions of anti-obese and anti-dyspepsia of C.cassia.

  15. In vivo efficacy of trovafloxacin against Bacteroides fragilis in mixed infection with either Escherichia coli or a vancomycin-resistant strain of Enterococcus faecium in an established-abscess murine model.

    Science.gov (United States)

    Stearne, L E; Gyssens, I C; Goessens, W H; Mouton, J W; Oyen, W J; van der Meer, J W; Verbrugh, H A

    2001-05-01

    The pharmacodynamic and pharmacokinetic properties of trovafloxacin were studied in a standardized murine model of established subcutaneous abscesses. Daily dosing regimens of 37.5 to 300 mg/kg every 8 h (q8h) or every 24 h (q24h) were started 3 days after inoculation with mixtures containing either Bacteroides fragilis-Escherichia coli-autoclaved cecal contents (ACC) or B. fragilis-vancomycin-resistant Enterococcus faecium (VREF)-ACC. Treatment was continued for 3 or 5 days. The efficacy of treatment was determined by the decrease in abscess bacterial counts and abscess weights, as well as by the reduction in inflammation (biodistribution of (99m)Tc-HYNIC immunoglobulin G) compared to saline-treated controls. Trovafloxacin showed a significant dose-response effect on the bacterial counts, weight, and inflammation of B. fragilis-E. coli abscesses after 3 and/or 5 days of treatment. A maximum 3.4 and 3.1 log(10) reduction in CFU/abscess in the respective B. fragilis and E. coli bacterial counts was attained after 5 days of treatment with daily doses of 300 mg/kg. The peak serum concentration was more predictive for effect than the area under the concentration-time curve. The C(max) was the pharmacodynamic index most predictive for success, and the efficacy of the q24h regimens was significantly better than the q8h regimens. The antibiotic was ineffective against the VREF in mixed infection with B. fragilis, while the killing of the anaerobe in the same combination was significantly less than in the E. coli combination (P abscesses. In addition, we have shown for the first time that a decrease in bacterial numbers also leads to a reduction in both abscess weight and inflammation.

  16. Preparation and Identification of Polyclonal Antibody Against a Nov-el α-Galactosidase from Bacteroides fragilis%新型α-半乳糖苷酶多克隆抗体的制备及特异性鉴定

    Institute of Scientific and Technical Information of China (English)

    李素波; 高红伟; 张雪; 鲍国强; 檀英霞; 王颖丽; 季守平; 宫锋

    2013-01-01

    目的:制备高效价、高特异性的新型α-半乳糖苷酶的兔多抗,并鉴定该抗体的特异性。方法:用脆弱类杆菌来源的基因重组α-半乳糖苷酶(纯度大于90%)免疫新西兰大白兔,获得α-半乳糖苷酶的兔抗血清,并经HiTrap rProtein A柱纯化获得高纯度的抗体;用间接ELISA法检测抗体效价,Western印迹评价抗体的特异性。结果:通过免疫法得到了α-半乳糖苷酶的兔多克隆抗体血清,抗体效价达1∶1×106,经rProtein A柱纯化后获得了高效价、高纯度的抗体,Western印迹显示该抗体特异性地与新型α-半乳糖苷酶结合。结论:获得了新型α-半乳糖苷酶的高效价、高特异性的兔多克隆抗体,可用于血型转变过程中残留α-半乳糖苷酶含量的特异性检测。%Objective: To prepare high titer and high specific rabbit polyclonal antibody against a novel α-galac-tosidase from Bacteroides fragilis. Methods: The New Zealand rabbits were immunized with purified recombinant bacteria α-galactosidase(the purity>90%). Rabbit sera were purified by HiTrap rProtein A column, and its titer and specificity were detected by ELISA and Western blotting respectively Results: The purity of antibody protein was about 95%. And the titer of rabbit sera were 1∶1 × 106. Western blotting showed that the antibody reacted with α-galactosidase only. Conclusion: We had obtained high titer and high purity rabbit polyclonal antibody ofα-galactosidase. The antibody can be used in detecting the minimal amount of residual α-galactosidase involved in conversion of blood type B to O.

  17. Polaribacter gen. nov., with three new species, P. irgensii sp. nov., P. franzmannii sp. nov. and P. filamentus sp. nov., gas vacuolate polar marine bacteria of the Cytophaga-Flavobacterium-Bacteroides group and reclassification of 'Flectobacillus glomeratus' as Polaribacter glomeratus comb. nov

    Science.gov (United States)

    Gosink, J. J.; Woese, C. R.; Staley, J. T.

    1998-01-01

    Several psychrophilic, gas vacuolate strains of the Cytophage-Flavobacterium-Bacteroides (CFB) phylogenetic group were isolated from sea ice and water from the Arctic and the Antarctic. The closest taxonomically defined species by 16S rRNA sequence analysis is 'Flectobacillus glomeratus'. However, 'Flc. glomeratus' is phylogenetically distant from the Flectobacillus type species, Flc. major. On the basis of phenotypic, genotypic and 16S rRNA sequence analyses we propose a new genus, Polaribacter, with three new species, Polaribacter irgensii strain 23-P (ATCC 700398), Polaribacter franzmannii strain 301 (ATCC 700399) and Polaribacter filamentus strain 215 (ATCC 700397). P. filamentus is the type species of the genus. None of these species exhibits a cosmopolitan or bipolar distribution. This is the first taxonomic description of gas vacuolate bacteria in the CFB group. Additionally, we propose that 'Flc. glomeratus' be reclassified to the genus Polaribacter as P. glomeratus, comb. nov.

  18. IgA production in the large intestine is modulated by a different mechanism than in the small intestine: Bacteroides acidifaciens promotes IgA production in the large intestine by inducing germinal center formation and increasing the number of IgA+ B cells.

    Science.gov (United States)

    Yanagibashi, Tsutomu; Hosono, Akira; Oyama, Akihito; Tsuda, Masato; Suzuki, Ami; Hachimura, Satoshi; Takahashi, Yoshimasa; Momose, Yoshika; Itoh, Kikuji; Hirayama, Kazuhiro; Takahashi, Kyoko; Kaminogawa, Shuichi

    2013-04-01

    It has been demonstrated that intestinal commensal bacteria induce immunoglobulin (Ig) A production by promoting the development of gut-associated lymphoid tissues in the small intestine. However, the precise mechanism whereby these bacteria modulate IgA production in the large intestine, which harbors the majority of intestinal commensals, is poorly understood. In addition, it is not known which commensal bacteria induce IgA production in the small intestine and which induce production in the large intestine. To address these issues, we generated gnotobiotic mice mono-associated with different murine commensal bacteria by inoculating germ-free (GF) mice with Lactobacillus johnsonii or Bacteroides acidifaciens. In GF mice, IgA production was barely detectable in the small intestine and was not detected in the large intestine. Interestingly, total IgA secretion in the large intestinal mucosa of B. acidifaciens mono-associated (BA) mice was significantly greater than that of GF and L. johnsonii mono-associated (LJ) mice. However, there was no difference in total IgA production in the small intestine of GF, LJ and BA mice. In addition, in the large intestine of BA mice, the expression of IgA(+) cells and germinal center formation were more remarkable than in GF and LJ mice. Furthermore, B. acidifaciens-specific IgA was detected in the large intestine of BA mice. These results suggest that the production of IgA in the large intestine may be modulated by a different mechanism than that in the small intestine, and that B. acidifaciens is one of the predominant bacteria responsible for promoting IgA production in the large intestine.

  19. Xylose metabolism in Bacteroides xylanolyticus X5-1.

    NARCIS (Netherlands)

    Biesterveld, S.

    1994-01-01

    Plant cell walls represent a major part of the available biomass on earth. They are mainly composed of the energy-rich polymers lignin, cellulose, and hemicellulose. For many decades, research is done to exploit agricultural and forestry wastes as renewable resources. Much research was focused on th

  20. 抗脆弱类杆菌和产气荚膜杆菌McAb池在外科感染快速诊断中的应用%Application of monoclonal antibody pool against Bacteroides fragilis and Clostridium perfringens in rapid diagnosis in surgical infection

    Institute of Scientific and Technical Information of China (English)

    张雅萍; 甘露; 常山

    2001-01-01

    目的 制备抗脆弱类杆菌和抗产气荚膜杆菌单克隆抗体池,并用于快速诊断及时指导临床治疗。方法 采用间接免疫荧光抗体染色法(IFA)和免疫酶标抗体染色法(ELA)对我院1998~1999年191例外科感染患者的标本进行细菌学检测,并与常规培养法进行比较。结果 3种方法从191份标本中分别检出脆弱类杆菌53株(27.7%)和55株(28.8%)以及25株(13.1%);检出产气荚膜杆菌12株(6.3%)和11株(5.8%)以及6株(3.1%)。IFA和ELA法2种厌氧菌检出率明显高于CM法。但IFA和ELA法之间检出率差异无显著性。结论 自制抗脆弱类杆菌和抗产气荚膜杆菌的McAb池,检测平时常见的脆弱类杆菌和战时常见的产气荚膜杆菌,敏感性高,特异性强,简便,快速,便于推广。%Objective To prepare monoclonal antibody (McAb) pool against Bacteroides fragilis and Clostridium perfringens and evaluated its effect in rapid diagnosis in surgical infection. Methods After the preparation of monoclonal antibodies against B. fragilis and C. perfringens, 191 specimens collected from infectious patients was detected with indirect immunofluorescent antibody (IFA) and enzyme labeled antibody (ELA). The results were compared with routine cultural method (CM). Results Among the 191 specimens, 53 (27.7%), 55 (28.8%) and 25 (13.1%)strains of B. fragilis were detected with IFA, ELA and CM respectively, and for C.perfringens, 12(6.3%), 11(5.8%), and 6(3.1%) strains were found. The detectable rate of anaerobic bacteria by IFA and ELA was higher than by CM, but no difference was found between these 2. Conclusion The self-made McAb pool against B.fagilis and C.perfringens might be a rapid, specific, sensitive and simple McAb pool for detecting B.fragilis in surgical infection and C.perfringens in wartime.

  1. Bacteroides forsythus: sensibilidade a antimicrobianos em amostras de pacientes portadores de periodontite Bacteroides forsythus: sensitivity to antimicrobial agents in samples from patients with periodontitis

    Directory of Open Access Journals (Sweden)

    Roberto Fraga Moreira LOTUFO

    2001-03-01

    Full Text Available Os autores realizaram teste de sensibilidade antimicrobiana in vitro (técnica de diluição em ágar para 105 cepas de B. forsythus obtidas de pacientes portadores de periodontite. De acordo com o teste realizado, o microrganismo demonstrou ser sensível ao metronidazol (100% das cepas testadas e à amoxicilina (94% das cepas testadas, enquanto 72% e 65% das cepas foram susceptíveis à tetraciclina e ciprofloxacina, respectivamente. O metronidazol e a amoxicilina parecem ser os antimicrobianos indicados para o tratamento de infecções periodontais nas quais B. forsythus seja o patógeno predominante.An in vitro antimicrobial sensitivity test (technique of agar dilution was carried out for 105 clinical isolates of B. forsythus from patients with periodontitis. Metronidazole and amoxicillin were the most efficient drugs and, thus, are indicated for the treatment of periodontal infections in which this microorganism is the most prevalent pathogen.

  2. Utilización de cepas de bacteroides spp. como probiótico en conejos

    OpenAIRE

    Pérez de Rozas Ruiz de Gauna, Ana Mª; Castellà Gómez, Gemma

    2015-01-01

    La utilización de antimicrobianos, de forma metafiláxica, para mantener la salud de los animales en las granjas de producción, puede ser problemático en un futuro próximo, debido a las altas tasas de resistencias que se están observando. Esta situación obliga a replantearse medidas alternativas, las más habituales basadas en el uso de prebióticos, probióticos o la combinación de ambos (simbióticos). El objetivo principal de este trabajo ha sido el de seleccionar cepas de diferentes especies d...

  3. Utilización de cepas de bacteroides spp. como probiótico en conejos

    OpenAIRE

    Pérez de Rozas Ruiz de Gauna, Ana Mª

    2014-01-01

    La utilización de antimicrobianos, de forma metafiláxica, para mantener la salud de los animales en las granjas de producción, puede ser problemático en un futuro próximo, debido a las altas tasas de resistencias que se están observando. Esta situación obliga a replantearse medidas alternativas, las más habituales basadas en el uso de prebióticos, probióticos o la combinación de ambos (simbióticos). El objetivo principal de este trabajo ha sido el de seleccionar cepas de diferentes especi...

  4. The rag locus of porphyromonas gingivalis might arise from bacteroides via horizontal gene transfer

    OpenAIRE

    Z. Su; Kong, F.; Wang, S.; J. Chen; Yin, R.; Zhou, C.; Zhang, Y.; He, Z; Shi, Y.; Xue, Y.; X. Shi; Lu, L.; Shao, Q.; H. Xu

    2010-01-01

    Porphyromonas gingivalis is regarded as one of the risk factors of periodontitis. P. gingivalis exhibits a wide variety of genotypes. Many insertion sequences (ISs), located in their chromosomes, made P. gingivalis differentiate into virulent and avirulent strains. In this research, we investigated the prevalence of P. gingivalis in the gingival crevicular fluid (GCF) among periodontitis patients from Zhenjiang, China, detected the P. gingivalis rag locus distributions by multiplex polymerase...

  5. Bacteroides Fragilis OmpA: Utility as a Live Vaccine Vector for Biodefense Agents

    Science.gov (United States)

    2008-01-01

    described extensively [25]. We have recently described these loops in monomeric porins from Acinetobacter baumannii [26], B. fragilis [14], and P...heat-modifiable proteins from the outer membrane of Porphyromonas asaccharolytica and Acinetobacter baumannii . Anaerobe 5, 43-50. 2 Jousimies-Somer...encoding a pore- forming protein from a clinical isolate of Acinetobacter baumannii . Curr. Microbiol. 47, 434-443. Table 1. Primers used for the

  6. Differential metabolism of Exopolysaccharides from probiotic Lactobacilli by the human gut symbiont Bacteroides thetaiotaomicron

    NARCIS (Netherlands)

    Lammerts van Bueren, Alica; Saraf, Aakanksha; Martens, Eric C; Dijkhuizen, Lubbert

    2015-01-01

    Probiotic microorganisms are ingested as food or supplements and impart positive health benefits to consumers. Previous studies have indicated that probiotics transiently reside in the gastrointestinal tract and in addition to modulating commensal species diversity, also increase the expression of g

  7. Two Sinorhizobium meliloti glutaredoxins regulate iron metabolism and symbiotic bacteroid differentiation

    OpenAIRE

    Benyamina, S.M.; Baldacci-Cresp, F.; Couturier, J; Chibani, K.; J. Hopkins; Bekki, A.; Lajudie de, Philippe; Rouhier, N.; Jacquot, J P; Alloing, G; A Puppo; Frendo, P

    2013-01-01

    Legumes interact symbiotically with bacteria of the Rhizobiaceae to form nitrogen-fixing root nodules. We investigated the contribution of the three glutaredoxin (Grx)-encoding genes present in the Sinorhizobium meliloti genome to this symbiosis. SmGRX1 (CGYC active site) and SmGRX3 (CPYG) recombinant proteins displayed deglutathionylation activity in the 2-hydroethyldisulfide assay, whereas SmGRX2 (CGFS) did not. Mutation of SmGRX3 did not affect S.meliloti growth or symbiotic capacities. In...

  8. Requirement of succinate dehydrogenase activity for symbiotic bacteroid differentiation of Rhizobium meliloti in alfalfa nodules.

    OpenAIRE

    Gardiol, A E; Truchet, G L; Dazzo, F. B.

    1987-01-01

    Transmission electron microscopy was used to study the cellular morphologies of a wild-type Rhizobium meliloti strain (L5-30), a nitrogen fixation-ineffective (Fix-) succinate dehydrogenase mutant (Sdh-) strain, and a Fix+ Sdh+ revertant strain within alfalfa nodules and after free-living growth in a minimal medium containing 27 mM mannitol plus 20 mM succinate. The results showed a requirement of succinate dehydrogenase activity for symbiotic differentiation and maintenance of R. meliloti ba...

  9. Porphyromonas gingivalis, Bacteroides forsythus and other putative periodontal pathogens in subjects with and without periodontal destruction

    NARCIS (Netherlands)

    van Winkelhoff, AJ; Loos, BG; van der Reijden, WA; van der Velden, U

    2002-01-01

    Background and aims: Bacteria play an essential role in the pathogenesis of destructive periodontal disease. It has been suggested that not all bacteria associated with periodontitis may be normal inhabitants of a periodontally healthy dentition. In particular, Porphyromonas gingivalis and Actinobac

  10. Medicago truncatula ENOD40-1 and ENOD40-2 are both involved in nodule initiation and bacteroid development

    NARCIS (Netherlands)

    Wan, X.; Hontelez, J.; Lillo, A.; Guarnerio, C.; Peut, van de D.; Fedorova, E.; Bisseling, T.; Franssen, H.

    2007-01-01

    The establishment of a nitrogen-fixing root nodule on legumes requires the induction of mitotic activity of cortical cells leading to the formation of the nodule primordium and the infection process by which the bacteria enter this primordium. Several genes are up-regulated during these processes, a

  11. Development of EUCAST disk diffusion method for susceptibility testing of the Bacteroides fragilis group isolates

    DEFF Research Database (Denmark)

    Nagy, Elisabeth; Justesen, Ulrik Stenz; Eitel, Zsuzsa

    2015-01-01

    -clavulanic acid, cefoxitin, clindamycin, imipenem, metronidazole, moxifloxacin, piperacillin/tazobactam, tigecycline by agar dilution method previously. The inhibition zones of the same antibiotics including meropenem disc were determined by the disc diffusion on Brucella blood agar supplemented with haemin...

  12. Effects of DNA Extraction Procedures on Bacteroides Profiles in Fecal Samples From Various Animals Determined by Terminal Restriction Fragment Length Polymorphism Analysis

    Science.gov (United States)

    A major assumption in microbial source tracking is that some fecal bacteria are specific to a host animal, and thus provide unique microbial fingerprints that can be used to differentiate hosts. However, the DNA information obtained from a particular sample may be biased dependi...

  13. Bacteroides isolated from four mammalian hosts lack host specific 16S rRNA gene phylogeny and carbon and nitrogen utilization patterns

    Science.gov (United States)

    Within the distal gut of mammals are trillions of microbes that utilize nutrients from diet, intestinal mucosa, and other gut microbes. One hundred three (103) isolates of B. ovatus, B. thetaiotaomicron, and B. xylanisolvens were recovered from cow, goat, human, and pig fecal enrichments with cellul...

  14. Normal luminal bacteria, especially Bacteroides species, mediate chronic colitis, gastritis, and arthritis in HLA-B27/human beta2 microglobulin transgenic rats.

    OpenAIRE

    Rath, H. C.; Herfarth, H H; Ikeda, J S; Grenther, W B; Hamm, T. E.; Balish, E.; Taurog, J D; Hammer, R. E.; Wilson, K. H.; Sartor, R B

    1996-01-01

    Genetic and environmental factors are important in the pathogenesis of clinical and experimental chronic intestinal inflammation. We investigated the influence of normal luminal bacteria and several groups of selected bacterial strains on spontaneous gastrointestinal and systemic inflammation in HLA-B27 transgenic rats. Rats maintained germfree for 3-9 mo were compared with littermates conventionalized with specific pathogen-free bacteria. Subsequently, germfree transgenic rats were colonized...

  15. G protein-coupled receptor120 (GPR120) transcription in intestinal epithelial cells is significantly affected by bacteria belonging to the Bacteroides, Proteobacteria, and Firmicutes phyla.

    Science.gov (United States)

    Fredborg, M; Theil, P K; Jensen, B B; Purup, S

    2012-12-01

    Free fatty acids (FFA) are produced in the intestine by microbial fermentation. Recently, a family of G protein-coupled receptors (GPR) acting as FFA transporters has been reported including GPR120, which is expressed by intestinal epithelial cells. The GPR120 has been reported to affect the expression of glucagon-like peptide (GLP)-1 as well as function as a control point for anti-inflammatory effects. The aim of the present study was to evaluate whether 12 selected intestinal bacteria, representing the 4 major phyla present in the intestine, affect intestinal epithelial cell GPR120 and GLP-1 mRNA abundance. Supernatants of the 12 bacteria were added to differentiated Caco-2 intestinal epithelial cells cultured on filter inserts in concentrations corresponding to a cell:bacteria ratio of 1:200. After 4 h of incubation, changes in cellular mRNA of GLP-1 and GPR120 by bacterial supernatant were examined using real-time reverse transcriptase polymerase chain reaction. The abundance of GLP-1 mRNA decreased when cells were exposed to 4 of the 12 supernatants (P ≤ 0.05) compared with cells without bacteria added. Supernatants from 8 of the 12 bacteria analyzed increased the mRNA level of GPR120 (P ≤ 0.05) compared with cells without bacteria added. The alteration in cellular GPR120 mRNA was observed with bacteria categorized as either probiotics or bacteria capable of inducing an anti-inflammatory effect. The beneficial effect of these bacteria may very well be mediated by regulation of GPR120. The regulation of GPR120 by intestinal microbiota represents a direct signaling pathway for gut bacteria to affect host health and metabolism.

  16. G protein-coupled receptor 120 (GPR120) transcription in intestinal epithelial cells is significantly affected by bacteria belonging to the Bacteroides, Proteobacteria, and Firmicutes phyla

    DEFF Research Database (Denmark)

    Fredborg, Marlene; Theil, Peter Kappel; Jensen, Bent Borg;

    2012-01-01

    Free fatty acids (FFA) are produced in the intestine by microbial fermentation. Recently, a family of G protein-coupled receptors (GPR) acting as FFA transporters has been reported including GPR120, which is expressed by intestinal epithelial cells. The GPR120 has been reported to affect the expr....... The regulation of GPR120 by intestinal microbiota represents a direct signaling pathway for gut bacteria to affect host health and metabolism...... ≤ 0.05) compared with cells without bacteria added. The alteration in cellular GPR120 mRNA was observed with bacteria categorized as either probiotics or bacteria capable of inducing an anti-inflammatory effect. The beneficial effect of these bacteria may very well be mediated by regulation of GPR120...

  17. In vivo efficacy of trovafloxacin against Bacteroides fragilis in mixed infection with either Escherichia coli or a vancomycin-resistant strain of Enterococcus faecium in an established-abscess murine model.

    NARCIS (Netherlands)

    L.E.T. Stearne (Lorna); I.C. Gyssens (Inge); W.H.F. Goessens (Wil); J.W. Mouton (Johan); W.J. Oyen (Wim); J.W. van der Meer; H.A. Verbrugh (Henri)

    2001-01-01

    textabstractThe pharmacodynamic and pharmacokinetic properties of trovafloxacin were studied in a standardized murine model of established subcutaneous abscesses. Daily dosing regimens of 37.5 to 300 mg/kg every 8 h (q8h) or every 24 h (q24h) were started 3 days after i

  18. Inactivation of murine norovirus 1, coliphage phiX174, and Bacteroides [corrected] fragilis phage B40-8 on surfaces and fresh-cut iceberg lettuce by hydrogen peroxide and UV light.

    Science.gov (United States)

    Li, Dan; Baert, Leen; De Jonghe, Maarten; Van Coillie, Els; Ryckeboer, Jaak; Devlieghere, Frank; Uyttendaele, Mieke

    2011-02-01

    In this study, the inactivating properties of liquid hydrogen peroxide (L-H(2)O(2)), vaporized hydrogen peroxide (V-H(2)O(2)), UV light, and a combination of V-H(2)O(2) and UV light were tested on murine norovirus 1 (MNV-1) and bacteriophages (φX174 and B40-8) as models for human noroviruses. Disinfection of surfaces was examined on stainless steel discs based on European Standard EN 13697 (2001). For fresh-produce decontamination, a mixture of the viruses was inoculated onto shredded iceberg lettuce and treated after overnight incubation at 2°C. According to our results, L-H(2)O(2) (2.1%) was able to inactivate MNV-1 and φX174 on stainless steel discs by approximately 4 log(10) units within 10 min of exposure, whereas for B40-8, 15% of L-H(2)O(2) was needed to obtain a similar reduction in 10 min. Only a marginal reduction (≤1 log(10) unit after 5 min of exposure) by V-H(2)O(2) (2.52%) was achieved for the tested model viruses, although in combination with UV light, a 4-log(10)-unit decrease within 5 min of treatment was observed on stainless steel discs. Similar trends were observed for the decontamination of shredded iceberg lettuce, but the viral decline was reduced. These results demonstrated that both L-H(2)O(2) and a combination of V-H(2)O(2) and UV light can be used for norovirus inactivation on surfaces; V-H(2)O(2) (2.52%) in combination with UV light is promising for decontamination of fresh produce with much less consumption of water and disinfectant.

  19. Inactivation of murine Norovirus-1, coliphage φX174 and Bacteroides fragilis phage B40-8 on surfaces and fresh cut iceberg lettuce by hydrogen peroxide and UV light

    OpenAIRE

    2011-01-01

    In this study, the inactivating properties of liquid hydrogen peroxide (L-H2O2), vaporized hydrogen peroxide (V-H2O2), UV light, and a combination of V-H2O2 and UV light were tested on murine norovirus 1 (MNV-1) and bacteriophages (φX174 and B40-8) as models for human noroviruses. Disinfection of surfaces was examined on stainless steel discs based on European Standard EN 13697 (2001). For fresh-produce decontamination, a mixture of the viruses was inoculated onto shredded iceberg lettuce and...

  20. Convergent Evolution of Endosymbiont Differentiation in Dalbergioid and Inverted Repeat-Lacking Clade Legumes Mediated by Nodule-Specific Cysteine-Rich Peptides1

    Science.gov (United States)

    Czernic, Pierre; Gully, Djamel; Cartieaux, Fabienne; Moulin, Lionel; Guefrachi, Ibtissem; Patrel, Delphine; Pierre, Olivier; Fardoux, Joël; Chaintreuil, Clémence; Nguyen, Phuong; Gressent, Frédéric; Da Silva, Corinne; Poulain, Julie; Wincker, Patrick; Rofidal, Valérie; Hem, Sonia; Barrière, Quentin; Arrighi, Jean-François; Mergaert, Peter; Giraud, Eric

    2015-01-01

    Nutritional symbiotic interactions require the housing of large numbers of microbial symbionts, which produce essential compounds for the growth of the host. In the legume-rhizobium nitrogen-fixing symbiosis, thousands of rhizobium microsymbionts, called bacteroids, are confined intracellularly within highly specialized symbiotic host cells. In Inverted Repeat-Lacking Clade (IRLC) legumes such as Medicago spp., the bacteroids are kept under control by an arsenal of nodule-specific cysteine-rich (NCR) peptides, which induce the bacteria in an irreversible, strongly elongated, and polyploid state. Here, we show that in Aeschynomene spp. legumes belonging to the more ancient Dalbergioid lineage, bacteroids are elongated or spherical depending on the Aeschynomene spp. and that these bacteroids are terminally differentiated and polyploid, similar to bacteroids in IRLC legumes. Transcriptome, in situ hybridization, and proteome analyses demonstrated that the symbiotic cells in the Aeschynomene spp. nodules produce a large diversity of NCR-like peptides, which are transported to the bacteroids. Blocking NCR transport by RNA interference-mediated inactivation of the secretory pathway inhibits bacteroid differentiation. Together, our results support the view that bacteroid differentiation in the Dalbergioid clade, which likely evolved independently from the bacteroid differentiation in the IRLC clade, is based on very similar mechanisms used by IRLC legumes. PMID:26286718

  1. Convergent Evolution of Endosymbiont Differentiation in Dalbergioid and Inverted Repeat-Lacking Clade Legumes Mediated by Nodule-Specific Cysteine-Rich Peptides.

    Science.gov (United States)

    Czernic, Pierre; Gully, Djamel; Cartieaux, Fabienne; Moulin, Lionel; Guefrachi, Ibtissem; Patrel, Delphine; Pierre, Olivier; Fardoux, Joël; Chaintreuil, Clémence; Nguyen, Phuong; Gressent, Frédéric; Da Silva, Corinne; Poulain, Julie; Wincker, Patrick; Rofidal, Valérie; Hem, Sonia; Barrière, Quentin; Arrighi, Jean-François; Mergaert, Peter; Giraud, Eric

    2015-10-01

    Nutritional symbiotic interactions require the housing of large numbers of microbial symbionts, which produce essential compounds for the growth of the host. In the legume-rhizobium nitrogen-fixing symbiosis, thousands of rhizobium microsymbionts, called bacteroids, are confined intracellularly within highly specialized symbiotic host cells. In Inverted Repeat-Lacking Clade (IRLC) legumes such as Medicago spp., the bacteroids are kept under control by an arsenal of nodule-specific cysteine-rich (NCR) peptides, which induce the bacteria in an irreversible, strongly elongated, and polyploid state. Here, we show that in Aeschynomene spp. legumes belonging to the more ancient Dalbergioid lineage, bacteroids are elongated or spherical depending on the Aeschynomene spp. and that these bacteroids are terminally differentiated and polyploid, similar to bacteroids in IRLC legumes. Transcriptome, in situ hybridization, and proteome analyses demonstrated that the symbiotic cells in the Aeschynomene spp. nodules produce a large diversity of NCR-like peptides, which are transported to the bacteroids. Blocking NCR transport by RNA interference-mediated inactivation of the secretory pathway inhibits bacteroid differentiation. Together, our results support the view that bacteroid differentiation in the Dalbergioid clade, which likely evolved independently from the bacteroid differentiation in the IRLC clade, is based on very similar mechanisms used by IRLC legumes.

  2. NCBI nr-aa BLAST: CBRC-MLUC-01-0598 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-MLUC-01-0598 ref|ZP_03207828.1| hypothetical protein BACPLE_01456 [Bacteroides plebe...ius DSM 17135] gb|EDY96150.1| hypothetical protein BACPLE_01456 [Bacteroides plebeius DSM 17135] ZP_03207828.1 5.5 28% ...

  3. NCBI nr-aa BLAST: CBRC-TTRU-01-0884 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-0884 ref|ZP_03210142.1| hypothetical protein BACPLE_03833 [Bacteroides plebe...ius DSM 17135] gb|EDY94379.1| hypothetical protein BACPLE_03833 [Bacteroides plebeius DSM 17135] ZP_03210142.1 0.12 22% ...

  4. Novel Probiotic Therapies for Autism

    Science.gov (United States)

    2013-09-01

    commensal Bacteroides fragilis corrects gut permeability and ameliorates defects in communicative, stereotypic, anxiety-like and sensorimotor behaviors...2010; Hooper et al., 2012). In particular, the human commensal Bacteroides fragilis exhibits therapeutic properties in mouse models of both...colitis and multiple sclerosis (MS) (Ochoa-Reparaz et al., 2010; Round et al., 2010). Therefore, we are exploring the utility of commensal bacteria in

  5. NCBI nr-aa BLAST: CBRC-DNOV-01-2520 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DNOV-01-2520 ref|YP_001297577.1| alginate O-acetylation protein [Bacteroides v...ulgatus ATCC 8482] gb|ABR37955.1| alginate O-acetylation protein [Bacteroides vulgatus ATCC 8482] YP_001297577.1 4.6 33% ...

  6. Characterisation by proteomics of peribacteroid space and peribacteroid membrane preparations from pea (¤Pisum sativum¤) symbiosomes

    DEFF Research Database (Denmark)

    Saalbach, G.; Erik, P.; Wienkoop, S.

    2002-01-01

    The legume Rhizobium symbiosis leads to the formation of a new compartment in the plant cell, the symbiosome. This compartment harbours the bacteroids surrounded by a peribacteroid membrane (PBM) originating from the plant plasma membrane. The PBM and the space between the PBM and the bacteroid...

  7. NCBI nr-aa BLAST: CBRC-MMUS-16-0028 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-MMUS-16-0028 ref|NP_811436.1| alpha-rhamnosidase [Bacteroides thetaiotaomicron... VPI-5482] gb|AAO77630.1| alpha-rhamnosidase [Bacteroides thetaiotaomicron VPI-5482] NP_811436.1 6.7 24% ...

  8. NCBI nr-aa BLAST: CBRC-XTRO-01-0040 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-0040 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 1e-11 37% ...

  9. NCBI nr-aa BLAST: CBRC-PABE-23-0015 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PABE-23-0015 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 1e-10 34% ...

  10. NCBI nr-aa BLAST: CBRC-GGAL-35-0039 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-GGAL-35-0039 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 7e-04 29% ...

  11. NCBI nr-aa BLAST: CBRC-PTRO-24-0002 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-24-0002 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 5e-11 39% ...

  12. NCBI nr-aa BLAST: CBRC-TSYR-01-0668 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TSYR-01-0668 ref|NP_813030.1| hypothetical protein BT_4119 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO79224.1| pectate lyase [Bacteroides thetaiotaomicron VPI-5482] NP_813030.1 2.4 37% ...

  13. NCBI nr-aa BLAST: CBRC-XTRO-01-3254 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-3254 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 2e-14 31% ...

  14. NCBI nr-aa BLAST: CBRC-DRER-07-0096 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DRER-07-0096 ref|NP_809575.1| hypothetical protein BT_0662 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO75769.1| O-antigen polymerase [Bacteroides thetaiotaomicron VPI-5482] NP_809575.1 0.052 26% ...

  15. NCBI nr-aa BLAST: CBRC-PABE-17-0001 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PABE-17-0001 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 1e-08 30% ...

  16. NCBI nr-aa BLAST: CBRC-XTRO-01-1901 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-1901 ref|NP_809995.1| Na+/solute symporter [Bacteroides thetaiotaomicr...on VPI-5482] gb|AAO76189.1| Na+/solute symporter [Bacteroides thetaiotaomicron VPI-5482] NP_809995.1 6.0 20% ...

  17. NCBI nr-aa BLAST: CBRC-XTRO-01-1047 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-1047 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 1e-12 29% ...

  18. NCBI nr-aa BLAST: CBRC-BTAU-01-2762 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-BTAU-01-2762 ref|NP_809349.1| arabinose-proton symporter [Bacteroides thetaiotao...micron VPI-5482] gb|AAO75543.1| arabinose-proton symporter [Bacteroides thetaiotaomicron VPI-5482] NP_809349.1 1.9 26% ...

  19. NCBI nr-aa BLAST: CBRC-PMAR-01-0565 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PMAR-01-0565 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 9e-11 30% ...

  20. NCBI nr-aa BLAST: CBRC-XTRO-01-3864 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-3864 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 1e-06 32% ...

  1. NCBI nr-aa BLAST: CBRC-LAFR-01-1776 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-LAFR-01-1776 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 8.9 30% ...

  2. NCBI nr-aa BLAST: CBRC-GGOR-01-0989 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-GGOR-01-0989 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 0.006 25% ...

  3. NCBI nr-aa BLAST: CBRC-PTRO-20-0065 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-20-0065 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 6e-06 37% ...

  4. NCBI nr-aa BLAST: CBRC-XTRO-01-2290 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-2290 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 0.032 25% ...

  5. NCBI nr-aa BLAST: CBRC-ACAR-01-0080 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-ACAR-01-0080 ref|NP_810942.1| hypothetical protein BT_2029 [Bacteroides thetaiotao...micron VPI-5482] gb|AAO77136.1| conserved hypothetical protein [Bacteroides thetaiotaomicron VPI-5482] NP_810942.1 5e-17 39% ...

  6. NCBI nr-aa BLAST: CBRC-TTRU-01-1191 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-1191 ref|ZP_02070692.1| hypothetical protein BACUNI_02116 [Bacteroides uniform...is ATCC 8492] gb|EDO54112.1| hypothetical protein BACUNI_02116 [Bacteroides uniformis ATCC 8492] ZP_02070692.1 1.1 22% ...

  7. NCBI nr-aa BLAST: CBRC-TTRU-01-1354 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-1354 ref|ZP_02070692.1| hypothetical protein BACUNI_02116 [Bacteroides uniform...is ATCC 8492] gb|EDO54112.1| hypothetical protein BACUNI_02116 [Bacteroides uniformis ATCC 8492] ZP_02070692.1 0.40 23% ...

  8. NCBI nr-aa BLAST: CBRC-VPAC-01-0352 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-VPAC-01-0352 ref|ZP_02070696.1| hypothetical protein BACUNI_02120 [Bacteroides uniform...is ATCC 8492] gb|EDO54116.1| hypothetical protein BACUNI_02120 [Bacteroides uniformis ATCC 8492] ZP_02070696.1 0.97 24% ...

  9. NCBI nr-aa BLAST: CBRC-VPAC-01-0246 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-VPAC-01-0246 ref|ZP_02070696.1| hypothetical protein BACUNI_02120 [Bacteroides uniform...is ATCC 8492] gb|EDO54116.1| hypothetical protein BACUNI_02120 [Bacteroides uniformis ATCC 8492] ZP_02070696.1 0.64 25% ...

  10. NCBI nr-aa BLAST: CBRC-TTRU-01-0916 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-0916 ref|ZP_02070692.1| hypothetical protein BACUNI_02116 [Bacteroides uniform...is ATCC 8492] gb|EDO54112.1| hypothetical protein BACUNI_02116 [Bacteroides uniformis ATCC 8492] ZP_02070692.1 0.054 22% ...

  11. Failure to fix nitrogen by non-reproductive symbiotic rhizobia triggers host sanctions that reduce fitness of their reproductive clonemates.

    Science.gov (United States)

    Oono, Ryoko; Anderson, Carolyn G; Denison, R Ford

    2011-09-07

    The legume-rhizobia symbiosis is a classical mutualism where fixed carbon and nitrogen are exchanged between the species. Nonetheless, the plant carbon that fuels nitrogen (N(2)) fixation could be diverted to rhizobial reproduction by 'cheaters'--rhizobial strains that fix less N(2) but potentially gain the benefit of fixation by other rhizobia. Host sanctions can decrease the relative fitness of less-beneficial reproductive bacteroids and prevent cheaters from breaking down the mutualism. However, in certain legume species, only undifferentiated rhizobia reproduce, while only terminally differentiated rhizobial bacteroids fix nitrogen. Sanctions were, therefore, tested in two legume species that host non-reproductive bacteroids. We demonstrate that even legume species that host non-reproductive bacteroids, specifically pea and alfalfa, can severely sanction undifferentiated rhizobia when bacteroids within the same nodule fail to fix N(2). Hence, host sanctions by a diverse set of legumes play a role in maintaining N(2) fixation.

  12. Identification of Human Intestinal Bacteria that Promote or Inhibit Inflammation

    Science.gov (United States)

    2012-11-01

    Vibrio " cholerae " Proteus"sp." Bacteroides"thetaiotaomicron" Escherichea"coli"(EH)" Escherichea"coli"(HMC)" Bacteroidetes"fragilis...equally  inflammatory  species   Escherichia   coli,   Vibrio   colerae   and   Bacteroides   fragilis.   Similarly,   the...the   equally   inflammatory  species   Vibrio  colerae  and  Bacteroides  fragilis.  These   findings   are  

  13. Effect of β-glucanase and xylanase supplementation of barley- and rye-based diets on caecal microbiota of broiler chickens

    DEFF Research Database (Denmark)

    Josefiak, Damian; Rutkowski, A; Kaczmarek, S

    2010-01-01

    in the broiler caeca were Clostridium coccoides-Eubacterium rectale followed by Bacteroides sp., Lactobacillus sp./Enterococcus sp., Bifidobacterium sp. and Enterobacteriaceae. For both cereal types, the enzyme supplementation significantly decreased the relative amount of Enterobacteriaceae. 4. The T...

  14. Symbiotic leghemoglobins are crucial for nitrogen fixation in legume root nodules but not for general plant growth and development

    DEFF Research Database (Denmark)

    Ott, Thomas; van Dongen, Joost T; Günther, Catrin

    2005-01-01

    fixation (SNF). In legumes, SNF occurs in specialized organs, called nodules, which contain millions of nitrogen-fixing rhizobia, called bacteroids. The induction of nodule-specific plant genes, including those encoding symbiotic leghemoglobins (Lb), accompanies nodule development. Leghemoglobins...

  15. Symbiotic Legume Nodules Employ Both Rhizobial Exo- and Endo-Hydrogenases to Recycle Hydrogen Produced by Nitrogen Fixation

    OpenAIRE

    Ciccolella, Christopher O.; Raynard, Nathan A.; John H-M Mei; Derek C Church; Ludwig, Robert A.

    2010-01-01

    BACKGROUND: In symbiotic legume nodules, endosymbiotic rhizobia (bacteroids) fix atmospheric N(2), an ATP-dependent catalytic process yielding stoichiometric ammonium and hydrogen gas (H(2)). While in most legume nodules this H(2) is quantitatively evolved, which loss drains metabolic energy, certain bacteroid strains employ uptake hydrogenase activity and thus evolve little or no H(2). Rather, endogenous H(2) is efficiently respired at the expense of O(2), driving oxidative phosphorylation, ...

  16. Mucosa-associated bacteria in two middle-aged women diagnosed with collagenous colitis

    Institute of Scientific and Technical Information of China (English)

    Rita J Gustafsson; Bodil Ohlsson; Cecilia Benoni; Bengt Jeppsson; Crister Olsson

    2012-01-01

    AIM:To characterize the colon microbiota in two women histologically diagnosed with collagenous colitis using a culture-independent method.METHODS:Biopsies were taken from the ascending colon and the total DNA was extracted.Universal bacterial primers were used to amplify the bacterial 16S rRNA genes.The amplicons were then cloned into competent Escherichia coli cells.The clones were sequenced and identified by comparison to known sequences.RESULTS:The clones could be divided into 44 different phylotypes.The microbiota was dominated by Firmicutes and Bacteroidetes.Seven phylotypes were found in both patients and constituted 47.5% of the total number of clones.Of these,the most dominating were clones similar to Bacteroides cellulosilyticus,Bacteroides caccae,Bacteroides thetaiotaomicron,Bacteroides uniformis and Bacteroides dorei within Bacteroidetes.Sequences similar to Faecalibacterium prausnitzii and C/ostridium citroniae were also found in both patients.CONCLUSION:A predominance of potentially pathogenic Bacteroidesspp.,and the presence of clones showing similarity to Clostridium clostridioforme were found but the overall colon microbiota showed similarities to a healthy one.Etiologies for collagenous colitis other than an adverse bacterial flora must also be considered.

  17. Presence of microbial and chemical source tracking markers in roof-harvested rainwater and catchment systems for the detection of fecal contamination.

    Science.gov (United States)

    Waso, M; Ndlovu, T; Dobrowsky, P H; Khan, S; Khan, W

    2016-09-01

    Microbial source tracking (MST) and chemical source tracking (CST) markers were utilized to identify fecal contamination in harvested rainwater and gutter debris samples. Throughout the sampling period, Bacteroides HF183 was detected in 57.5 % of the tank water samples and 95 % of the gutter debris samples, while adenovirus was detected in 42.5 and 52.5 % of the tank water and gutter debris samples, respectively. Human adenovirus was then detected at levels ranging from below the detection limit to 316 and 1253 genome copies/μL in the tank water and debris samples, respectively. Results for the CST markers showed that salicylic acid (average 4.62 μg/L) was the most prevalent marker (100 %) in the gutter debris samples, caffeine (average 18.0 μg/L) was the most prevalent in the tank water samples (100 %) and acetaminophen was detected sporadically throughout the study period. Bacteroides HF183 and salicylic acid (95 %) and Bacteroides HF183 and caffeine (80 %) yielded high concurrence frequencies in the gutter debris samples. In addition, the highest concurrence frequency in the tank water samples was observed for Bacteroides HF183 and caffeine (60 %). The current study thus indicates that Bacteroides HF183, salicylic acid and caffeine may potentially be applied as source tracking markers in rainwater catchment systems in order to supplement fecal indicator analyses.

  18. Production of α-galactosylceramide by a prominent member of the human gut microbiota.

    Directory of Open Access Journals (Sweden)

    Laura C Wieland Brown

    2013-07-01

    Full Text Available While the human gut microbiota are suspected to produce diffusible small molecules that modulate host signaling pathways, few of these molecules have been identified. Species of Bacteroides and their relatives, which often comprise >50% of the gut community, are unusual among bacteria in that their membrane is rich in sphingolipids, a class of signaling molecules that play a key role in inducing apoptosis and modulating the host immune response. Although known for more than three decades, the full repertoire of Bacteroides sphingolipids has not been defined. Here, we use a combination of genetics and chemistry to identify the sphingolipids produced by Bacteroides fragilis NCTC 9343. We constructed a deletion mutant of BF2461, a putative serine palmitoyltransferase whose yeast homolog catalyzes the committed step in sphingolipid biosynthesis. We show that the Δ2461 mutant is sphingolipid deficient, enabling us to purify and solve the structures of three alkaline-stable lipids present in the wild-type strain but absent from the mutant. The first compound was the known sphingolipid ceramide phosphorylethanolamine, and the second was its corresponding dihydroceramide base. Unexpectedly, the third compound was the glycosphingolipid α-galactosylceramide (α-GalCer(Bf, which is structurally related to a sponge-derived sphingolipid (α-GalCer, KRN7000 that is the prototypical agonist of CD1d-restricted natural killer T (iNKT cells. We demonstrate that α-GalCer(Bf has similar immunological properties to KRN7000: it binds to CD1d and activates both mouse and human iNKT cells both in vitro and in vivo. Thus, our study reveals BF2461 as the first known member of the Bacteroides sphingolipid pathway, and it indicates that the committed steps of the Bacteroides and eukaryotic sphingolipid pathways are identical. Moreover, our data suggest that some Bacteroides sphingolipids might influence host immune homeostasis.

  19. Production of α-Galactosylceramide by a Prominent Member of the Human Gut Microbiota

    Science.gov (United States)

    Kashyap, Purna C.; Williams, Brianna B.; Clardy, Jon; Kronenberg, Mitchell; Sonnenburg, Justin L.; Comstock, Laurie E.; Bluestone, Jeffrey A.; Fischbach, Michael A.

    2013-01-01

    While the human gut microbiota are suspected to produce diffusible small molecules that modulate host signaling pathways, few of these molecules have been identified. Species of Bacteroides and their relatives, which often comprise >50% of the gut community, are unusual among bacteria in that their membrane is rich in sphingolipids, a class of signaling molecules that play a key role in inducing apoptosis and modulating the host immune response. Although known for more than three decades, the full repertoire of Bacteroides sphingolipids has not been defined. Here, we use a combination of genetics and chemistry to identify the sphingolipids produced by Bacteroides fragilis NCTC 9343. We constructed a deletion mutant of BF2461, a putative serine palmitoyltransferase whose yeast homolog catalyzes the committed step in sphingolipid biosynthesis. We show that the Δ2461 mutant is sphingolipid deficient, enabling us to purify and solve the structures of three alkaline-stable lipids present in the wild-type strain but absent from the mutant. The first compound was the known sphingolipid ceramide phosphorylethanolamine, and the second was its corresponding dihydroceramide base. Unexpectedly, the third compound was the glycosphingolipid α-galactosylceramide (α-GalCerBf), which is structurally related to a sponge-derived sphingolipid (α-GalCer, KRN7000) that is the prototypical agonist of CD1d-restricted natural killer T (iNKT) cells. We demonstrate that α-GalCerBf has similar immunological properties to KRN7000: it binds to CD1d and activates both mouse and human iNKT cells both in vitro and in vivo. Thus, our study reveals BF2461 as the first known member of the Bacteroides sphingolipid pathway, and it indicates that the committed steps of the Bacteroides and eukaryotic sphingolipid pathways are identical. Moreover, our data suggest that some Bacteroides sphingolipids might influence host immune homeostasis. PMID:23874157

  20. Effects of microgravity on the binding of acetylsalicylic acid by Rhizobium leguminosarum bv. trifolii

    Science.gov (United States)

    Urban, James E.; Gerren, Richard; Zoelle, Jeffery

    1995-07-01

    Bacteroids can be induced in vitro by treating growing Rhizobium leguminosarum bv. trifolii with succinic acid or succinic acid structural analogs like acetylsalicylic acid. Quantitating bacteroid induction by measuring acetylsalicylic binding under normal (1 g) conditions showed two forms of binding to occur. In one form of binding cells immediately bound comparatively high levels of acetylsalicylic acid, but the binding was quickly reversed. The second form of binding increased with time by first-order kinetics, and reached saturation in 40 s. Similar experiments performed in the microgravity environment aboard the NASA 930 aircraft showed only one form of binding and total acetylsalicylic acid bound was 32% higher than at 1 g.

  1. Treatment of colitis with a commensal gut bacterium engineered to secrete human TGF-beta1 under the control of dietary xylan

    Science.gov (United States)

    Background: Growth factors have shown promise in treating inflammatory bowel disease. They are unstable when administered orally and required in higher doses with systemic administration. In consideration of these problems, we have engineered the commensal bacterium Bacteroides ovatus for the con...

  2. [Comparative study of the antimicrobial effect of various cavity liners used in conservative dentistry].

    Science.gov (United States)

    Pumarola Suñé, J; Espias Gómez, A; Canalda Sahli, C

    1989-01-01

    We have compared the microbiological activity of the following cavity liners: Life, Dycal II, Calcipulpe, Pure calcium hydroxide and Cavitec; against five different bacterial strains: Veillonella parvula, Bacteroides fragilis, Peptococcus s.p., Staphylococcus aureus, and Streptococcus beta hemolytic: The results demonstrate the higher antimicrobial activity of the manufactured cavity liners with calcium hydroxide base in comparison with the pure calcium hydroxide.

  3. Global changes in gene expression in Sinorhizobium meliloti 1021 under microoxic and symbiotic conditions.

    Science.gov (United States)

    Becker, Anke; Bergès, Hélène; Krol, Elizaveta; Bruand, Claude; Rüberg, Silvia; Capela, Delphine; Lauber, Emmanuelle; Meilhoc, Eliane; Ampe, Frédéric; de Bruijn, Frans J; Fourment, Joëlle; Francez-Charlot, Anne; Kahn, Daniel; Küster, Helge; Liebe, Carine; Pühler, Alfred; Weidner, Stefan; Batut, Jacques

    2004-03-01

    Sinorhizobium meliloti is an alpha-proteobacterium that alternates between a free-living phase in bulk soil or in the rhizosphere of plants and a symbiotic phase within the host plant cells, where the bacteria ultimately differentiate into nitrogen-fixing organelle-like cells, called bacteroids. As a step toward understanding the physiology of S. meliloti in its free-living and symbiotic forms and the transition between the two, gene expression profiles were determined under two sets of biological conditions: growth under oxic versus microoxic conditions, and in free-living versus symbiotic state. Data acquisition was based on both macro- and microarrays. Transcriptome profiles highlighted a profound modification of gene expression during bacteroid differentiation, with 16% of genes being altered. The data are consistent with an overall slow down of bacteroid metabolism during adaptation to symbiotic life and acquisition of nitrogen fixation capability. A large number of genes of unknown function, including potential regulators, that may play a role in symbiosis were identified. Transcriptome profiling in response to oxygen limitation indicated that up to 5% of the genes were oxygen regulated. However, the microoxic and bacteroid transcriptomes only partially overlap, implying that oxygen contributes to a limited extent to the control of symbiotic gene expression.

  4. AcEST: DK958680 [AcEST

    Lifescience Database Archive (English)

    Full Text Available YLGL 588 + RS+ +V R LG+ Sbjct: 251 EGR-MLRSKADVFRLLGI 267 >tr|B5CVC7|B5CVC7_9BACE Putative uncharacterized protein OS=Bacteroides ple...beius DSM 17135 GN=BACPLE_00656 PE=4 SV=1 Length = 1370

  5. GenBank blastx search result: AK104703 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104703 001-037-D02 AF129406.1 Bacteroides fragilis alkyl hydroperoxide reductase subunit C (ahp...C) and alkyl hydroperoxide reductase subunit F (ahpF) genes, complete cds.|BCT BCT 8e-36 +3 ...

  6. GenBank blastx search result: AK104317 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104317 001-024-C03 AF129406.1 Bacteroides fragilis alkyl hydroperoxide reductase subunit C (ahp...C) and alkyl hydroperoxide reductase subunit F (ahpF) genes, complete cds.|BCT BCT 8e-19 +3 ...

  7. GenBank blastx search result: AK058859 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058859 001-005-E08 AF129406.1 Bacteroides fragilis alkyl hydroperoxide reductase subunit C (ahp...C) and alkyl hydroperoxide reductase subunit F (ahpF) genes, complete cds.|BCT BCT 4e-11 +1 ...

  8. Dicty_cDB: Contig-U13810-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 4( CP000139 |pid:none) Bacteroides vulgatus ATCC 8482,... 35 1.3 DQ286524_1( DQ286524 |pid:none) Microspor...um canis dipeptidyl pepti... 34 2.2 D42121_1( D42121 |pid:none) Flavobacterium meni

  9. Transepithelial activation of human leukocytes by probiotics and commensal bacteria: role of Enterobacteriaceae-type endotoxin

    DEFF Research Database (Denmark)

    Bäuerlein, A.; Ackermann, S.; Parlesak, Alexandr

    2009-01-01

    Escherichia coli K12, probiotic E. coli Nissle, EPEC) induced basolateral production of TNF-alpha, IFN-gamma, IL 6, 8, and 10. Gram-positive probiotics (Lactobacillus spp. and Bifidobacterium spp.) had virtually no effect. In addition, commensals (Enterococcus faecalis, Bacteroides vulgatus) and food...

  10. In vitro growth of four individual human gut bacteria on oligosaccharides produced by chemoenzymatic synthesis

    DEFF Research Database (Denmark)

    Vigsnæs, Louise Kristine; Nakai, Hiroyuki; Hemmingsen, Lene

    2013-01-01

    . These OS have not been previously tested for effects of bacterial growth and here the ability of all 19 OS to support growth of four gastrointestinal bacteria: three probiotic bacteria Bifidobacterium lactis, Bifidobacterium longum, and Lactobacillus acidophilus, and one commensal bacterium, Bacteroides...

  11. Detection and source identification of faecal pollution in non-sewered catchment by means of host-specific molecular markers.

    Science.gov (United States)

    Ahmed, W; Powell, D; Goonetilleke, A; Gardner, T

    2008-01-01

    Multiple host-specific molecular markers were used to detect the sources of faecal pollution in a mixed land use non-sewered catchment in Southeast Queensland, Australia. These markers included human-specific Bacteroides (HF183 and HF134), cattle-specific Bacteroides (CF128), dog-specific Bacteroides (BacCan) and human-specific enterococci surface protein (esp) markers. The sensitivity and specificity of these markers were determined by testing 197 faecal samples from 13 host groups. The overall sensitivity and specificity of these markers was high (sensitivity>/=85% and specificity>/=93%) indicating their suitability for detecting the sources of faecal pollution. Of the 16 samples collected from the study area, 14 (87%) were positive for at least one of the molecular marker tested. Amongst all the markers, cattle-specific CF128 was more prevalent than others, followed by human-specific HF183 which was consistently detected in samples collected from sites within close proximity to urban development. Significant correlations were found between E. coli and enterococci concentrations with the positive/negative results of human-specific Bacteroides HF183 (psources of human faecal pollution in surface waters in Southeast Queensland, Australia.

  12. Epidemiology and Antimicrobial Susceptibilities of Wound Isolates of Obligate Anaerobes from Combat Casualties

    Science.gov (United States)

    White, Brian K.; Mende, Katrin; Weintrob, Amy C.; Beckius, Miriam L.; Zera, Wendy C.; Lu, Dan; Bradley, William; Tribble, David R.; Schnaubelt, Elizabeth R.; Murray, Clinton K.

    2015-01-01

    Data from recent conflicts related to war wounds and obligate anaerobes are limited. We define the epidemiology and antimicrobial susceptibility of obligate anaerobes from Iraq and Afghanistan casualties (6/2009–12/2013), as well as their association with clinical outcomes. Susceptibility against eleven antibiotics (7 classes) was tested. Overall, 59 patients had 119 obligate anaerobes identified (83 were first isolates). Obligate anaerobes were isolated 7–13 days post-injury, primarily from lower extremity wounds (43%), and were largely Bacteroides spp. (42%) and Clostridium spp. (19%). Patients with pelvic wounds were more likely to have Bacteroides spp. and concomitant resistant gram-negative aerobes. Seventy-three percent of isolates were resistant to ≥1 antimicrobials. Bacteroides spp. demonstrated the most resistance (16% of first isolates). Patients with resistant isolates had similar outcomes to those with susceptible strains. Serial recovery of isolates occurred in 15% of patients and was significantly associated with isolation of Bacteroides spp., along with resistant gram-negative aerobes. PMID:26607420

  13. Fecal microbiota composition and frailty

    NARCIS (Netherlands)

    van Tongeren, SP; Slaets, JPJ; Harmsen, HJM; Welling, GW

    2005-01-01

    The relationship between fecal microbiota composition and frailty in the elderly was studied. Fecal samples from volunteers with high frailty scores showed a significant reduction in the number of lactobacilli (26-fold). At much higher population levels, both the Bacteroides/Prevotella (threefold) a

  14. Dicty_cDB: Contig-U10128-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available :none) Bacteroides thetaiotaomicron VP... 37 0.89 DQ273698_3( DQ273698 |pid:none) Crocody...5 3.4 AJ810453_3( AJ810453 |pid:none) Crocodylus porosus complete mitoch... 34 4.4 EF156850_1( EF156850 |pid

  15. Impact of probiotics on colonic microflora in patients with colitis

    DEFF Research Database (Denmark)

    Reddy, B. S.; Ahmed, J.; Macfie, J.;

    2010-01-01

    years (IQR 50–65). An average of 22 T-RF’s was identified in each patient. Dice cluster analysis showed that each patient had a unique microbial spectrum and did not change significantly at different points in the study in both groups. T-RF 102bp potential representing Bacteroides fragilis was the only...

  16. Domain Modeling: NP_115873.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_115873.1 chr17 Crystal structure of a domain of phenylacetate-coenzyme A ligase ...from Bacteroides vulgatus ATCC 8482 p3gxsa_ chr17/NP_115873.1/NP_115873.1_apo_386-519.pdb psi-blast 0 ...

  17. Nodulin gene expression in the developing pea root nodule.

    NARCIS (Netherlands)

    Govers, F.

    1987-01-01

    Infection of leguminous plants with bacteria of the genus Rhizobium results in a symbiotic interaction which brings about the development of an entirely new organ on the plant, the root nodule. Within this organ about half of the plant cells are inhabited by bacteroids, the endosymblotic form

  18. Rhizobium Strain Effects on Yield and Bleeding Sap Amino Compounds in Pisum sativum

    DEFF Research Database (Denmark)

    Rosendahl, Lis

    1984-01-01

    for a higher percentage of the organic solutes transporting newly assimilated N from the root system than in the association with 1044. The Rhizobium strain effect on amino compound composition of the bleeding sap may indicate an influence of the bacteroids on either the N-assimilatory enzyme system...

  19. Legume receptors perceive the rhizobial lipochitin oligosaccharide signal molecules by direct binding

    DEFF Research Database (Denmark)

    Broghammer, Angelique; Krusell, Lene; Blaise, Mickaël

    2012-01-01

    Lipochitin oligosaccharides called Nod factors function as primary rhizobial signal molecules triggering legumes to develop new plant organs: root nodules that host the bacteria as nitrogen-fixing bacteroids. Here, we show that the Lotus japonicus Nod factor receptor 5 (NFR5) and Nod factor recep...

  20. The lipopolysaccharide lipid-a long chain fatty acid is important for rhizobium leguminosarum growth and stress adaptation in free-living and nodule environments

    Science.gov (United States)

    Rhizobium bacteria live in soil and plant environments, are capable of inducing symbiotic nodules on legumes, invade these nodules, and develop into bacteroids that fix atmospheric nitrogen into ammonium. Lipopolysaccharide (LPS) is anchored in the bacterial outer membrane through a specialized lipi...

  1. Quantitative Analysis of Intestinal Flora of Uygur and Han Ethnic Chinese Patients with Ulcerative Colitis.

    Science.gov (United States)

    Yao, Ping; Cui, Min; Wang, Haikun; Gao, Hongliang; Wang, Lei; Yang, Tao; Cheng, Yongbo

    2016-01-01

    Aim. To study the correlation between intestinal flora and ulcerative colitis by analyzing the abundance of Bacteroides, Fusobacterium, Clostridium, Bifidobacterium spp., and Faecalibacterium prausnitzii in the intestinal of ulcerative colitis (UC) patients and healthy controls with Uygur and Han ethnic. Methods. Bacterial genomic DNA was extracted from fecal samples and analyzed with real-time fluorescence quantitative polymerase chain reaction (PCR) to identify the abundance of Bacteroides, Fusobacterium, Clostridium, Bifidobacterium spp., and Faecalibacterium prausnitzii. Results. The samples from UC patients, Uygur and Han ethnic combined, had higher abundance of Bacteroides (P = 0.026) but lower Clostridium (P = 0.004), Bifidobacterium spp. (P = 0.009), and Faecalibacterium prausnitzii (P = 0.008) than those from healthy controls. Among UC patients, Bacteroides population was raised in acute UC patients (P ≤ 0.05), while the abundance of Clostridium, Bifidobacterium spp., Fusobacterium, and Faecalibacterium prausnitzii decreased (P ≤ 0.05) compared with the remission. In both UC patients group and control group, no difference was observed in the abundance of these 5 bacteria between the Han and the Uygur group. Conclusions. Variations in the abundance of these five bacterial strains in intestines may be associated with the occurrence of UC in Uygur and Han populations; however, these variations were not associated with ethnic difference.

  2. Dicty_cDB: Contig-U13889-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 60 5e-08 CP000139_431( CP000139 |pid:none) Bacteroides vulgatus ATCC 8482, ... 60 5e-08 FJ356060_1( FJ356060... |pid:none) Chorispora bungeana putative glyci... 60 5e-08 BX649404_1( BX649404 |pid:none) Zebrafish DNA seq

  3. Gut microbiota in 2015: Prevotella in the gut: choose carefully.

    Science.gov (United States)

    Ley, Ruth E

    2016-02-01

    Gut microbial communities often contain many Bacteroides or their close relatives, Prevotella, but not both. Prevotella strains are associated with plant-rich diets but are also linked with chronic inflammatory conditions. In 2015, papers probed the genomic diversity of Prevotella strains and interactions of Prevotella copri with its host and other bacteria.

  4. Quantitative Analysis of Intestinal Flora of Uygur and Han Ethnic Chinese Patients with Ulcerative Colitis

    Directory of Open Access Journals (Sweden)

    Ping Yao

    2016-01-01

    Full Text Available Aim. To study the correlation between intestinal flora and ulcerative colitis by analyzing the abundance of Bacteroides, Fusobacterium, Clostridium, Bifidobacterium spp., and Faecalibacterium prausnitzii in the intestinal of ulcerative colitis (UC patients and healthy controls with Uygur and Han ethnic. Methods. Bacterial genomic DNA was extracted from fecal samples and analyzed with real-time fluorescence quantitative polymerase chain reaction (PCR to identify the abundance of Bacteroides, Fusobacterium, Clostridium, Bifidobacterium spp., and Faecalibacterium prausnitzii. Results. The samples from UC patients, Uygur and Han ethnic combined, had higher abundance of Bacteroides (P=0.026 but lower Clostridium (P=0.004, Bifidobacterium spp. (P=0.009, and Faecalibacterium prausnitzii (P=0.008 than those from healthy controls. Among UC patients, Bacteroides population was raised in acute UC patients (P≤0.05, while the abundance of Clostridium, Bifidobacterium spp., Fusobacterium, and Faecalibacterium prausnitzii decreased (P≤0.05 compared with the remission. In both UC patients group and control group, no difference was observed in the abundance of these 5 bacteria between the Han and the Uygur group. Conclusions. Variations in the abundance of these five bacterial strains in intestines may be associated with the occurrence of UC in Uygur and Han populations; however, these variations were not associated with ethnic difference.

  5. Mixed Red-Complex Bacterial Infection in Periodontitis

    Directory of Open Access Journals (Sweden)

    N. Suzuki

    2013-01-01

    Full Text Available The red complex, which includes Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia (formerly Bacteroides forsythus, are recognized as the most important pathogens in adult periodontal disease. These bacteria are usually found together in periodontal pockets, suggesting that they may cause destruction of the periodontal tissue in a cooperative manner. This article discusses the interspecies pathogenic interactions within the red complex.

  6. Sustainable microbial water quality monitoring programme design using phage-lysis and multivariate techniques.

    Science.gov (United States)

    Nnane, Daniel Ekane

    2011-11-15

    Contamination of surface waters is a pervasive threat to human health, hence, the need to better understand the sources and spatio-temporal variations of contaminants within river catchments. River catchment managers are required to sustainably monitor and manage the quality of surface waters. Catchment managers therefore need cost-effective low-cost long-term sustainable water quality monitoring and management designs to proactively protect public health and aquatic ecosystems. Multivariate and phage-lysis techniques were used to investigate spatio-temporal variations of water quality, main polluting chemophysical and microbial parameters, faecal micro-organisms sources, and to establish 'sentry' sampling sites in the Ouse River catchment, southeast England, UK. 350 river water samples were analysed for fourteen chemophysical and microbial water quality parameters in conjunction with the novel human-specific phages of Bacteroides GB-124 (Bacteroides GB-124). Annual, autumn, spring, summer, and winter principal components (PCs) explained approximately 54%, 75%, 62%, 48%, and 60%, respectively, of the total variance present in the datasets. Significant loadings of Escherichia coli, intestinal enterococci, turbidity, and human-specific Bacteroides GB-124 were observed in all datasets. Cluster analysis successfully grouped sampling sites into five clusters. Importantly, multivariate and phage-lysis techniques were useful in determining the sources and spatial extent of water contamination in the catchment. Though human faecal contamination was significant during dry periods, the main source of contamination was non-human. Bacteroides GB-124 could potentially be used for catchment routine microbial water quality monitoring. For a cost-effective low-cost long-term sustainable water quality monitoring design, E. coli or intestinal enterococci, turbidity, and Bacteroides GB-124 should be monitored all-year round in this river catchment.

  7. Transcriptomic Analysis of Sinorhizobium meliloti and Medicago truncatula Symbiosis Using Nitrogen Fixation-Deficient Nodules.

    Science.gov (United States)

    Lang, Claus; Long, Sharon R

    2015-08-01

    The bacterium Sinorhizobium meliloti interacts symbiotically with legume plant hosts such as Medicago truncatula to form nitrogen-fixing root nodules. During symbiosis, plant and bacterial cells differentiate in a coordinated manner, resulting in specialized plant cells that contain nitrogen-fixing bacteroids. Both plant and bacterial genes are required at each developmental stage of symbiosis. We analyzed gene expression in nodules formed by wild-type bacteria on six plant mutants with defects in nitrogen fixation. We observed differential expression of 482 S. meliloti genes with functions in cell envelope homeostasis, cell division, stress response, energy metabolism, and nitrogen fixation. We simultaneously analyzed gene expression in M. truncatula and observed differential regulation of host processes that may trigger bacteroid differentiation and control bacterial infection. Our analyses of developmentally arrested plant mutants indicate that plants use distinct means to control bacterial infection during early and late symbiotic stages.

  8. In vitro activity of moxifloxacin against 923 anaerobes isolated from human intra-abdominal infections.

    Science.gov (United States)

    Goldstein, Ellie J C; Citron, Diane M; Warren, Yumi A; Tyrrell, Kerin L; Merriam, C Vreni; Fernandez, Helen

    2006-01-01

    The in vitro activity of moxifloxacin against 923 recent anaerobic isolates obtained from pretreatment cultures in patients with complicated intra-abdominal infections was studied using the CLSI M11-A-6 agar dilution method. Moxifloxacin was active against 87% (96 of 110) Bacteroides fragilis strains at accounting for most of the resistant isolates; excluding the aforementioned four resistant species, 86% (303 of 363) of Bacteroides species isolates and 94% (417 of 450) of all other genera and species were susceptible to < or = 2 microg/ml of moxifloxacin. Overall, moxifloxacin was active against 763 of 923 (83%) of strains at < or = 2 microg/ml, supporting its use as a monotherapy for some community-acquired intra-abdominal infections.

  9. Fecal microbiota imbalance in Mexican children with type 1 diabetes.

    Science.gov (United States)

    Mejía-León, María Esther; Petrosino, Joseph F; Ajami, Nadim Jose; Domínguez-Bello, María Gloria; de la Barca, Ana María Calderón

    2014-01-22

    Dysbiosis of the intestinal microbiota affecting the gut barrier could be triggering Type 1 Diabetes (T1D), the second most frequent autoimmune disease in childhood. This study compared the structure of the fecal microbiota in 29 mestizo children aged 7-18 years, including 8 T1D at onset, 13 T1D after 2 years treatment, and 8 healthy controls. Clinical information was collected, predisposing haplotypes were determined; the fecal DNA was extracted, the V4 region of the 16S rRNA gene amplified and 454-pyrosequenced. The newly diagnosed T1D cases had high levels of the genus Bacteroides (p microbiota dominated by Prevotella. Children with T1D treated for ≥2 years had levels of Bacteroides and Prevotella compared to those of the control group. The gut microbiota of newly diagnosed T1D cases is altered, but whether it is involved in disease causation or is a consequence of host selection remains unclear.

  10. [Antimicrobial susceptibility testing of anaerobic bacteria].

    Science.gov (United States)

    García-Sánchez, José E; García-Sánchez, Enrique; García-García, María Inmaculada

    2014-02-01

    The anaerobic bacteria resistance to antibiotics is increasing, and even has appeared against the most active of those, like metronidazol and carbapenems. This fact forces to make and periodical sensibility tests -at least in the most aggressive and virulent species, in cases that they are isolated from life locations and in the absence of therapeutic response- to check the local sensibility and to establish suitable empiric therapies, all based on multicentric studies carried out in order to this or well to check the activity of new antibiotics. For the laboratory routine, the easiest sensibility method is the E-test/MIC evaluator. Another alternative is microdilution, that's only normalized for Bacteroides. There are preliminary facts that allow the use of disc diffusion method in some species of Bacteroides and Clostridium. For the temporal and multicentric studies, the procedure is dilution in agar plate, the reference method.

  11. Synthesis and biological activity of a novel series of 17-azapentacyclo [6.6.5.0(2.7).0(9.14).0(15,19)]nonadeca-2,4,6,9,11,13-hexaen-16,18-dione derivatives.

    Science.gov (United States)

    Kuran, Bozena; Krawiecka, Mariola; Kossakowski, Jerzy; Szymanek, Ksenia; Kierzkowska, Marta; Młynarczyk, Grazyna

    2012-01-01

    In the search for novel antimicrobial agents, a series of new derivatives - N-substituted imides were prepared. All of the compounds were characterized by 'H NMR and ESI MS spectra. These derivatives were tested for antimicrobial activity. Microorganisms used in this study included aerobic and facultative anaerobic bacteria such as Staphylococcus aureus, Escherichia coli, Stenotrophomonas maltophilia, and obligatory anaerobes such as Bacteroides fragilis, Bacteroides thetaiotaomicron and Propionibacterium acnes. Moreover, Candida albicans yeast was used. For representatives of all species the MICs of the investigated compounds were determined. Most of investigated derivatives had no antimicrobial activity (MIC > 512 mg/L) except the derivative 22 which showed slight activity against Gram-positive aerobes and anaerobes.

  12. Dietary shifts affect the gastrointestinal microflora of the giant panda (Ailuropoda melanoleuca).

    Science.gov (United States)

    Williams, C L; Willard, S; Kouba, A; Sparks, D; Holmes, W; Falcone, J; Williams, C H; Brown, A

    2013-06-01

    Giant pandas exhibit seasonal changes in bamboo plant part preference. The influences on the gastrointestinal tracts (GIT) microbial populations were evaluated during a 14-month period for a pair of adult male and female giant pandas housed at the Memphis Zoo using traditional culturing methods to enumerate eight bacterial groups (total anaerobes, total aerobes (TAR), streptococci (STR), total enterics, Escherichia coli, Bacteroides spp., lactobacilli and Clostridium spp.). Both the male and female pandas altered bamboo consumption behaviours, with a sharp decrease in leaf preference in April 2010 and returning to high levels of leaf preference from June to October, corresponding to significant shifts in the densities of TAR, STR, and lactobacilli and Bacteroides spp. These findings indicate seasonal changes in food preference affect the assemblages of microbial populations within the GIT of the giant panda and contribute to a better understanding of the importance of bamboo in this species' foraging strategy.

  13. Influence of Forage Phenolics on Ruminal Fibrolytic Bacteria and In Vitro Fiber Degradation

    OpenAIRE

    Varel, Vincent H.; Jung, Hans-Joachim G.

    1986-01-01

    In vitro cultures of ruminal microorganisms were used to determine the effect of cinnamic acid and vanillin on the digestibility of cellulose and xylan. Cinnamic acid and vanillin depressed in vitro dry matter disappearance of cellulose 14 and 49%, respectively, when rumen fluid was the inoculum. The number of viable Bacteroides succinogenes cells, the predominant cellulolytic organism, was threefold higher for fermentations which contained vanillin than for control fermentations. When xylan ...

  14. Efficacy of fecal microbiota transplantation in 2 children with recurrent Clostridium difficile infection and its impact on their growth and gut microbiome.

    Science.gov (United States)

    Walia, Ritu; Garg, Shashank; Song, Yang; Girotra, Mohit; Cuffari, Carmen; Fricke, Wolfgang Florian; Dutta, Sudhir K

    2014-11-01

    Fecal microbiota transplantation (FMT) is recognized as an alternative therapeutic modality for recurrent Clostridium difficile infection (RCDI); however, data on its efficacy in children are lacking, including its effect on their growth and fecal microbiota. We report on 2 young children (microbiota diversity, especially proportion of Bacteroides. Our 2 cases illustrate the efficacy of FMT in children with RCDI and its positive effect on their growth and gut microbiota.

  15. Associations between common intestinal parasites and bacteria in humans as revealed by qPCR

    DEFF Research Database (Denmark)

    O'Brien Andersen, L.; Karim, A. B.; Roager, Henrik Munch

    2016-01-01

    Several studies have shown associations between groups of intestinal bacterial or specific ratios between bacterial groups and various disease traits. Meanwhile, little is known about interactions and associations between eukaryotic and prokaryotic microorganisms in the human gut. In this work, w...... of Bifidobacterium was subsequently performed, and the relative abundance of these bacteria across the four groups was compared. The relative abundance of Bacteroides in B- D- samples was significantly higher compared with B+ D- and B+ D+ samples (P ...

  16. Functional Characterization of SbmA, a Bacterial Inner Membrane Transporter Required for Importing the Antimicrobial Peptide Bac7(1-35)

    OpenAIRE

    Runti, Giulia; Lopez Ruiz, Maria del Carmen; Stoilova, Tatiana; Hussain, Rohanah; Jennions, Matthew; Choudhury, Hassanul G.; Benincasa, Monica; Gennaro, Renato; Beis, Konstantinos; Scocchi, Marco

    2013-01-01

    SbmA is an inner membrane protein of Gram-negative bacteria that is involved in the internalization of glycopeptides and prokaryotic and eukaryotic antimicrobial peptides, as well as of peptide nucleic acid (PNA) oligomers. The SbmA homolog BacA is required for the development of Sinorhizobium meliloti bacteroids within plant cells and favors chronic infections with Brucella abortus and Mycobacterium tuberculosis in mice. Here, we investigated functional features of SbmA/BacA using the prolin...

  17. Determination of reactive oxygen generated from natural medicines and their antibacterial activity

    Directory of Open Access Journals (Sweden)

    Noriko Tajima

    2016-08-01

    Galla chinensis generated 2.4×10−4 mol/L hydrogen peroxide from a 1 mg/mL solution. In bacterial growth tests, Galla chinensis extract had antibacterial activity against Escherichia coli, Staphylococcus aureus, Bacteroides thetaiotaomicron, Campylobacter sputorum biovar sputorum, Streptococcus salivarius thermophilus, Lactobacillus casei, and Bifidobacterium longum infantis. This antibacterial activity was decreased by the addition of catalase. It revealed that hydrogen peroxide which Galla chinensis produced participated in antibacterial activity.

  18. Rhizobium meliloti genes required for C4-dicarboxylate transport and symbiotic nitrogen fixation are located on a megaplasmid.

    OpenAIRE

    Watson, R J; Chan, Y K; Wheatcroft, R; Yang, A. F.; Han, S. H.

    1988-01-01

    A mutant of Rhizobium meliloti unable to transport C4 dicarboxylates (dct) was isolated after Tn5 mutagenesis. The mutant, 4F6, could not grow on aspartate or the tricarboxylic acid cycle intermediates succinate, fumarate, or malate. It produced symbiotically ineffective nodules on Medicago sativa in which bacteroids appeared normal, but the symbiotic zone was reduced and the plant cells contained numerous starch granules at their peripheries. Cosmids containing the dct region were obtained b...

  19. Role of Symbiotic Auxotrophy in the Rhizobium-Legume Symbioses

    OpenAIRE

    Jurgen Prell; Alexandre Bourdès; Shalini Kumar; Emma Lodwig; Arthur Hosie; Seonag Kinghorn; James White; Philip Poole

    2010-01-01

    Background Rhizobium leguminosarum bv. viciae mutants unable to transport branched-chain amino acids via the two main amino acid ABC transport complexes AapJQMP and BraDEFGC produce a nitrogen starvation phenotype when inoculated on pea (Pisum sativum) plants [1], [2]. Bacteroids in indeterminate pea nodules have reduced abundance and a lower chromosome number. They reduce transcription of pathways for branched-chain amino acid biosynthesis and become dependent on their provision by the host....

  20. Growth Conditions Determine the DNF2 Requirement for Symbiosis

    OpenAIRE

    Fathi Berrabah; Marie Bourcy; Anne Cayrel; Alexis Eschstruth; Samuel Mondy; Pascal Ratet; Benjamin Gourion

    2014-01-01

    Rhizobia and legumes are able to interact in a symbiotic way leading to the development of root nodules. Within nodules, rhizobia fix nitrogen for the benefit of the plant. These interactions are efficient because spectacularly high densities of nitrogen fixing rhizobia are maintained in the plant cells. DNF2, a Medicago truncatula gene has been described as required for nitrogen fixation, bacteroid's persistence and to prevent defense-like reactions in the nodules. This manuscript shows that...

  1. Acute Necrotizing Ulcerative Gingivitis: Microbial and Immunologic Studies

    Science.gov (United States)

    1983-10-01

    34 Odd ii 4n....00p IdaOdifir 0’ block flumber) Periodontal Disease Spirochetes Microbiology Fusobacteria immunology Bacteroides 20. AN3T7RAC~r C4.tft...and serological etudies with ’We 7. nucleatum isolates from patients with ANUG, chronic periodontitis , Juvenile periodontitis , and adults and children...routine periodontal procedures (34-37). Early studies on the histopathology of ANUG lesions reported that the pathological process appears to begin or the

  2. Necrotizing Soft-Tissue Infections: Clinical Guidelines

    Science.gov (United States)

    2009-10-01

    predictor of mortality in this disease Table 3. Causative Organisms in NSTI Group A beta-hemolytic Streptococcus ( pyogenes ) Anaerobes—Bacteroides...patients treated with hyperbaric oxygen Mascini et al30 In vitro comparison in 14 isolates of Streptococcus pyogenes II Clindamycin superior to penicillin...damycin compared with beta-lactam antibiotic treatment for invasive Streptococcus pyogenes infection. Pediatr Infect Dis J 1999;18:1096–100. 32. Wang R

  3. Gut-Associated Microbial Symbionts of the Marsh Fiddler Crab, Uca Pugnax

    Science.gov (United States)

    2004-09-01

    and readily digested starches (Stevens and Hume 1995), have sufficient endogenous enzymes to process their diets and therefore have been predicted to... polyacrylamide , 30-60% or 20-70% denaturant). Gels of 20-70% denaturant were used initially to assess the complete spectrum of 80 diversity patterns. A narrower...strict anaerobes involved in starch degradation (Mccarthy et al. 1988). Furthermore, Sebaldella termitidis, previously Bacteroides termitidis, produces

  4. Influencia del estrógeno en la enfermedad periodontal: revisión de literatura

    OpenAIRE

    2015-01-01

    La etiología de la enfermedad periodontal está bien definida, dentro de los agentes etiológicos que la causan podemos citar algunos microorganismos subgingivales como: Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Actinobacillus actinomycetemcomitans y espiroquetas. La susceptibilidad del huésped a estos agentes bacterianos también tiene un papel importante dentro del progreso y prevalencia de la enfermedad periodontal. Dentro de los factores de riesgo asociados con ...

  5. Chest wall actinomycosis in association with the use of an intra-uterine device.

    Science.gov (United States)

    McBride, W J; Hill, D R; Gordon, D L

    1995-02-01

    A 31 year old woman presented with a chest wall abscess due to Actinomyces israellii and Porphyromonas asaccharolytica (previously Bacteroides asaccharolyticus). She was a long-term user of an intra-uterine device (IUD) and, although asymptomatic, had radiological evidence of pelvic infection. Actinomyces-like organisms were seen on cervico-vaginal smears. The abscess was surgically drained, the IUD removed, and a prolonged course of amoxycillin/clavulanic acid given.

  6. Porphyromonas gingivalis Vesicles Enhance Attachment, and the Leucine-Rich Repeat BspA Protein Is Required for Invasion of Epithelial Cells by “Tannerella forsythia”

    OpenAIRE

    Inagaki, Satoru; Onishi, Shinsuke; Kuramitsu, Howard K.; Sharma, Ashu

    2006-01-01

    The human oral cavity harbors more than 500 species of bacteria. Periodontitis, a bacterially induced inflammatory disease that leads to tooth loss, is believed to result from infection by a select group of gram-negative periodontopathogens that includes Porphyromonas gingivalis, Treponema denticola, and “Tannerella forsythia” (opinion on name change from Tannerella forsythensis pending; formerly Bacteroides forsythus). Epithelial cell invasion by periodontopathogens is considered to be an im...

  7. Fermentation characteristics ofMegasphaera elsdeniiJ6 derived from pig feces on different lactate isomers

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiao-lin; SU Yong; ZHU Wei-yun

    2016-01-01

    D-Lactate-utilizing bacteria play important roles in maintaining the balance of gut lactate; however, studies on gut D-lactate-uti-lizing bacteria have been limited. This study aimed to isolate and identify D-lactate-utilizing bacteria from pig gut using the Hungate rol-tube method, and to investigate their metabolic characteristicsin vitro. Six different anaerobes were isolated from pig feces, which were identiifed as related toBacteroides fragilis, Bacteroides acidifaciens,Veilonela denticariosi, Veilonela caviae,Bacteroides uniformis, andMegasphaera elsdenibased on the 16S rRNA gene sequences. Al strains had a signiifcant ability to utilize D-lactate, which was concluded afterin vitro fermentation with 25 mmol L–1 D-lactate as the primary carbon source. Of al 6 strains,M. elsdeniJ6 showed the highest efifciency of D-lactate utilization and produced a higher ratio of butyrate in total short chain fatty acids (SCFAs). Thus, thein vitro fermentation characteristics of this strain in D-, L-, and DL-lactate mixtures (D-lactate:L-lactate=1:1 or 1:2) were further studied. The results showed that M. elsdeni J6 preferred utilizing D-lactate, and produced more SCFA when using D-lactate as the primary carbon source. The ifndings suggest that the administration of D-lactate-utilizing bacteria such asM. elsdeni J6 may have a potential advantage in the aleviation of D-lactic acidosis in the animal gut.

  8. Proline auxotrophy in Sinorhizobium meliloti results in a plant-specific symbiotic phenotype.

    Science.gov (United States)

    diCenzo, George C; Zamani, Maryam; Cowie, Alison; Finan, Turlough M

    2015-12-01

    In order to effectively manipulate rhizobium-legume symbioses for our benefit, it is crucial to first gain a complete understanding of the underlying genetics and metabolism. Studies with rhizobium auxotrophs have provided insight into the requirement for amino acid biosynthesis during the symbiosis; however, a paucity of available L-proline auxotrophs has limited our understanding of the role of L-proline biosynthesis. Here, we examined the symbiotic phenotypes of a recently described Sinorhizobium meliloti L-proline auxotroph. Proline auxotrophy was observed to result in a host-plant-specific phenotype. The S. meliloti auxotroph displayed reduced symbiotic capability with alfalfa (Medicago sativa) due to a decrease in nodule mass formed and therefore a reduction in nitrogen fixed per plant. However, the proline auxotroph formed nodules on white sweet clover (Melilotus alba) that failed to fix nitrogen. The rate of white sweet clover nodulation by the auxotroph was slightly delayed, but the final number of nodules per plant was not impacted. Examination of white sweet clover nodules by confocal microscopy and transmission electron microscopy revealed the presence of the S. meliloti proline auxotroph cells within the host legume cells, but few differentiated bacteroids were identified compared with the bacteroid-filled plant cells of WT nodules. Overall, these results indicated that L-proline biosynthesis is a general requirement for a fully effective nitrogen-fixing symbiosis, likely due to a transient requirement during bacteroid differentiation.

  9. Results From a Microbial Source-Tracking Study at Villa Angela Beach, Cleveland, Ohio, 2007

    Science.gov (United States)

    Bushon, Rebecca N.; Stelzer, Erin A.; Stoeckel, Donald M.

    2009-01-01

    During the 2007 recreational season at Villa Angela Beach in Cleveland, Ohio, scientists with the U.S. Geological Survey (USGS) and the Northeast Ohio Regional Sewer District (NEORSD) found high Escherichia coli (E. coli) concentrations that were not easily explained by results obtained to date in ongoing investigations of recreational water quality at the beach. To help understand the sources behind these elevated E. coli concentrations, the USGS and NEORSD sampled beach-area water for Bacteroides DNA markers. Bacteroides are a group of enteric bacteria that are being used in microbial source tracking, in hope that host-associated DNA markers could be used to indicate potential sources of E. coli in the Villa Angela environment. The USGS Ohio Water Microbiology Laboratory analyzed a total of 13 source samples (sewage and waterfowl feces) and 33 beach-area water and sand samples for three Bacteroides DNA markers. This report lists the results of those analyses, along with environmental conditions at Villa Angela on the dates that samples were collected.

  10. Geographic setting influences Great Lakes beach microbiological water quality

    Science.gov (United States)

    Haack, Sheridan K.; Fogarty, Lisa R.; Stelzer, Erin A.; Fuller, Lori M.; Brennan, Angela K.; Isaacs, Natasha M.; Johnson, Heather E.

    2013-01-01

    Understanding of factors that influence Escherichia coli (EC) and enterococci (ENT) concentrations, pathogen occurrence, and microbial sources at Great Lakes beaches comes largely from individual beach studies. Using 12 representative beaches, we tested enrichment cultures from 273 beach water and 22 tributary samples for EC, ENT, and genes indicating the bacterial pathogens Shiga-toxin producing E. coli (STEC), Shigella spp., Salmonella spp, Campylobacter jejuni/coli, and methicillin-resistant Staphylococcus aureus, and 108–145 samples for Bacteroides human, ruminant, and gull source-marker genes. EC/ENT temporal patterns, general Bacteroides concentration, and pathogen types and occurrence were regionally consistent (up to 40 km), but beach catchment variables (drains/creeks, impervious surface, urban land cover) influenced exceedances of EC/ENT standards and detections of Salmonella and STEC. Pathogen detections were more numerous when the EC/ENT Beach Action Value (but not when the Geometric Mean and Statistical Threshold Value) was exceeded. EC, ENT, and pathogens were not necessarily influenced by the same variables. Multiple Bacteroides sources, varying by date, occurred at every beach. Study of multiple beaches in different geographic settings provided new insights on the contrasting influences of regional and local variables, and a broader-scale perspective, on significance of EC/ENT exceedances, bacterial sources, and pathogen occurrence.

  11. Isoenzymes of superoxide dismutase in nodules of Phaseolus vulgaris L. , Pisum sativum L. , and Vigna unguiculata (L. ) Walp

    Energy Technology Data Exchange (ETDEWEB)

    Becana, M.; Paris, F.J.; Sandalio, L.M.; Del Rio, L.A. (IRNA, Salamanca (Spain) Unidad de Bioquimica Vegetal, Granada (Spain))

    1989-08-01

    The activity and isozymic composition of superoxide dismutase were determined in nodules of Phaseolus vulgaris L., Pisum sativum L., and Vigna unguiculata (L.) Walp. A Mn-SOD was present in Rhizobium and two in Bradyrhizobium and bacteroids. Nodule mitochondria from all three legume species had a single Mn-SOD with similar relative mobility, whereas the cytosol contained several CuZn-SODs: two in Phaseolus and Pisum, and four in Vigna. In the cytoplasm of V. unguiculata nodules, a Fe-containing SOD was also present, with an electrophoretic mobility between those of CuZn- and Mn-SODs, and an estimated molecular weight of 57,000. Total SOD activity of the soluble fraction of host cells, expressed on a nodule fresh weight basis, exceeded markedly that of bacteroids. Likewise, specific SOD activities of free-living bacteria were superior or equal to those of their symbiotic forms. Soluble extracts of bacteria and bacteroids did not show peroxidase activity, but the nodule cell cytoplasm contained diverse peroxidase isozymes which were readily distinguishable from leghemoglobin components by electrophoresis. Data indicated that peroxidases and leghemoglobins did not significantly interfere with SOD localization on gels. Treatment with chloroform-ethanol scarcely affected the isozymic pattern of SODs and peroxidases, and had limited success in the removal of leghemoglobin.

  12. In vitro fermentation of alginate and its derivatives by human gut microbiota.

    Science.gov (United States)

    Li, Miaomiao; Li, Guangsheng; Shang, Qingsen; Chen, Xiuxia; Liu, Wei; Pi, Xiong'e; Zhu, Liying; Yin, Yeshi; Yu, Guangli; Wang, Xin

    2016-06-01

    Alginate (Alg) has a long history as a food ingredient in East Asia. However, the human gut microbes responsible for the degradation of alginate and its derivatives have not been fully understood yet. Here, we report that alginate and the low molecular polymer derivatives of mannuronic acid oligosaccharides (MO) and guluronic acid oligosaccharides (GO) can be completely degraded and utilized at various rates by fecal microbiota obtained from six Chinese individuals. However, the derivative of propylene glycol alginate sodium sulfate (PSS) was not hydrolyzed. The bacteria having a pronounced ability to degrade Alg, MO and GO were isolated from human fecal samples and were identified as Bacteroides ovatus, Bacteroides xylanisolvens, and Bacteroides thetaiotaomicron. Alg, MO and GO can increase the production level of short chain fatty acids (SCFA), but GO generates the highest level of SCFA. Our data suggest that alginate and its derivatives could be degraded by specific bacteria in the human gut, providing the basis for the impacts of alginate and its derivates as special food additives on human health.

  13. Glycosaminoglycan-depolymerizing enzymes produced by anaerobic bacteria isolated from the human mouth.

    Science.gov (United States)

    Tipler, L S; Embery, G

    1985-01-01

    A number of obligately anaerobic bacteria, some implicated in periodontal disease, were screened for their ability to produce enzymes capable of degrading hyaluronic acid and chondroitin-4-sulphate. Two screening methods were used following anaerobic incubation at 37 degrees C for 7 days. One involved incorporating the respective substrates and bovine-serum albumin into agar plates and, after incubation, flooding the plates with 2 M acetic acid. Clear zones were produced around colonies which produced enzymes capable of depolymerizing the substrates. The second was a sensitive spectrophotometric procedure based on the ability of certain bacteria to produce eliminase enzymes, which degrade the substrates to unsaturated products having a characteristic u.v. absorption at 232 nm. Strains of Bacteroides gingivalis and Bacteroides melaninogenicus degraded both substrates whereas Bacteroides asaccharolyticus degraded neither substrate by either method. Some bacteria gave negative results with the plate method whereas the more sensitive spectrophotometric assay proved positive. The number of anaerobic bacteria capable of degrading hyaluronic acid and chondroitin-4-sulphate in vitro may therefore have been underestimated in previous studies.

  14. Symbiosomes: temporary moonlighting organelles.

    Science.gov (United States)

    Emerich, David W; Krishnan, Hari B

    2014-05-15

    Symbiosomes are a unique structural entity that performs the role of biological nitrogen fixation, an energy-demanding process that is the primary entryway of fixed nitrogen into the biosphere. Symbiosomes result from the infection of specific rhizobial strains into the roots of an appropriate leguminous host plant forming an organ referred to as a nodule. Within the infected plant cells of the nodule, the rhizobia are encased within membrane-bounded structures that develop into symbiosomes. Mature symbiosomes create an environment that allows the rhizobia to differentiate into a nitrogen-fixing form called bacteroids. The bacteroids are surrounded by the symbiosome space, which is populated by proteins from both eukaryotic and prokaryotic symbionts, suggesting this space is the quintessential component of symbiosis: an inter-kingdom environment with the single purpose of symbiotic nitrogen fixation. Proteins associated with the symbiosome membrane are largely plant-derived proteins and are non-metabolic in nature. The proteins of the symbiosome space are mostly derived from the bacteroid with annotated functions of carbon metabolism, whereas relatively few are involved in nitrogen metabolism. An appreciable portion of both the eukaryotic and prokaryotic proteins in the symbiosome are also 'moonlighting' proteins, which are defined as proteins that perform roles unrelated to their annotated activities when found in an unexpected physiological environment. The essential functions of symbiotic nitrogen fixation of the symbiosome are performed by co-operative interactions of proteins from both symbionts some of which may be performing unexpected roles.

  15. Bradyrhizobium BclA Is a Peptide Transporter Required for Bacterial Differentiation in Symbiosis with Aeschynomene Legumes.

    Science.gov (United States)

    Guefrachi, Ibtissem; Pierre, Olivier; Timchenko, Tatiana; Alunni, Benoît; Barrière, Quentin; Czernic, Pierre; Villaécija-Aguilar, José-Antonio; Verly, Camille; Bourge, Mickaël; Fardoux, Joël; Mars, Mohamed; Kondorosi, Eva; Giraud, Eric; Mergaert, Peter

    2015-11-01

    Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen-fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called nodule-specific cysteine-rich (NCR) peptides in the symbiotic nodule cells which house the bacteroids. NCR peptides are related to antimicrobial peptides of innate immunity. They induce the endosymbionts into a differentiated, enlarged, and polyploid state. The bacterial symbionts, on their side, evolved functions for the response to the NCR peptides. Here, we identified the bclA gene of Bradyrhizobium sp. strains ORS278 and ORS285, which is required for the formation of differentiated and functional bacteroids in the nodules of the NCR peptide-producing Aeschynomene legumes. The BclA ABC transporter promotes the import of NCR peptides and provides protection against the antimicrobial activity of these peptides. Moreover, BclA can complement the role of the related BacA transporter of Sinorhizobium meliloti, which has a similar symbiotic function in the interaction with Medicago legumes.

  16. Chromosomal DNA probes for the identification of asaccharolytic anaerobic pigmented bacterial rods from the oral cavity of cats.

    Science.gov (United States)

    Love, D N; Bailey, G D; Bastin, D

    1992-06-01

    A dot-blot hybridisation assay using isolated high molecular weight DNA as whole chromosomal probes of the cat pigmented asaccharolytic Bacteroides/Porphyromonas species was used against both purified high molecular weight DNA and DNA released on membranes from whole cells for the identification of B. salivosus and for its differentiation from the other anaerobic species isolated from normal and diseased mouths of cats and horses. 32P-labelled probes were compared with digoxigenin (DIG)-labelled probes (Boehringer-Mannheim). The whole chromosomal probes were specific--differentiating B. salivosus from a variety of species (including members of the genera Bacteroides, Fusobacterium, Eubacterium, and Prevotella) found in normal and abnormal mouths of cats and horses. Likewise, asaccharolytic black pigmented Group 2 strains were distinguishable from all strains tested. However, cat strains of P. gingivalis which show 68-76% DNA-DNA homology with human strain P. gingivalis ATCC 33277T, were not distinguishable from each other using either 32P-labelled or DIG-labelled probes. The minimum amount of pure Bacteroides DNA which could be detected by the 32P-labelled probe was 100-300 pg, while the amount of pure DNA detected by the DIG system was 1-3 mg after room temperature colour development for 1 h and 100-300 pg after 6 h colour development.

  17. The gut microbial community in metabolic syndrome patients is modified by diet.

    Science.gov (United States)

    Haro, Carmen; Garcia-Carpintero, Sonia; Alcala-Diaz, Juan F; Gomez-Delgado, Francisco; Delgado-Lista, Javier; Perez-Martinez, Pablo; Rangel Zuñiga, Oriol A; Quintana-Navarro, Gracia M; Landa, Blanca B; Clemente, Jose C; Lopez-Miranda, Jose; Camargo, Antonio; Perez-Jimenez, Francisco

    2016-01-01

    Intestinal microbiota changes may be involved in the development of metabolic syndrome (MetS), which is a multicomponent disorder frequently associated with obesity. The aim of this study was to test the effect of consuming two healthy diets: a Mediterranean diet and a low-fat high-carbohydrate diet, for 2years in the gut microbiota of MetS patients and those in the control group. We analyzed the differences in the bacterial community structure between the groups after 2years of dietary intervention (Mediterranean or low-fat diet) through quantitative polymerase chain reaction using primers, targeting specific bacterial taxa. We observed, at basal time, that the abundance of Bacteroides, Eubacterium and Lactobacillus genera is lower in the control group than in MetS patients, while Bacteroides fragilis group, Parabacteroides distasonis, Bacteroides thetaiotaomicron, Faecalibacterium prausnitzii, Fusobacterium nucleatum, Bifidobacterium longum, Bifidobacterium adolescentis, Ruminococcus flavefaciens subgroup and Eubacterium rectale are depleted in MetS patients (all P values diet partially restores the population of P. distasonis, B. thetaiotaomicron, F. prausnitzii, B. adolescentis and B. longum in MetS patients (all P values diet could be a useful tool to restore potentially beneficial members of the gut microbiota, although the stability of these changes over time still remains to be assessed.

  18. The evolution of cooperation within the gut microbiota.

    Science.gov (United States)

    Rakoff-Nahoum, Seth; Foster, Kevin R; Comstock, Laurie E

    2016-05-12

    Cooperative phenotypes are considered central to the functioning of microbial communities in many contexts, including communication via quorum sensing, biofilm formation, antibiotic resistance, and pathogenesis. The human intestine houses a dense and diverse microbial community critical to health, yet we know little about cooperation within this important ecosystem. Here we test experimentally for evolved cooperation within the Bacteroidales, the dominant Gram-negative bacteria of the human intestine. We show that during growth on certain dietary polysaccharides, the model member Bacteroides thetaiotaomicron exhibits only limited cooperation. Although this organism digests these polysaccharides extracellularly, mutants lacking this ability are outcompeted. In contrast, we discovered a dedicated cross-feeding enzyme system in the prominent gut symbiont Bacteroides ovatus, which digests polysaccharide at a cost to itself but at a benefit to another species. Using in vitro systems and gnotobiotic mouse colonization models, we find that extracellular digestion of inulin increases the fitness of B. ovatus owing to reciprocal benefits when it feeds other gut species such as Bacteroides vulgatus. This is a rare example of naturally-evolved cooperation between microbial species. Our study reveals both the complexity and importance of cooperative phenotypes within the mammalian intestinal microbiota.

  19. Differentiation of symbiotic cells and endosymbionts in Medicago truncatula nodulation are coupled to two transcriptome-switches.

    Directory of Open Access Journals (Sweden)

    Nicolas Maunoury

    Full Text Available The legume plant Medicago truncatula establishes a symbiosis with the nitrogen-fixing bacterium Sinorhizobium meliloti which takes place in root nodules. The formation of nodules employs a complex developmental program involving organogenesis, specific cellular differentiation of the host cells and the endosymbiotic bacteria, called bacteroids, as well as the specific activation of a large number of plant genes. By using a collection of plant and bacterial mutants inducing non-functional, Fix(- nodules, we studied the differentiation processes of the symbiotic partners together with the nodule transcriptome, with the aim of unravelling links between cell differentiation and transcriptome activation. Two waves of transcriptional reprogramming involving the repression and the massive induction of hundreds of genes were observed during wild-type nodule formation. The dominant features of this "nodule-specific transcriptome" were the repression of plant defense-related genes, the transient activation of cell cycle and protein synthesis genes at the early stage of nodule development and the activation of the secretory pathway along with a large number of transmembrane and secretory proteins or peptides throughout organogenesis. The fifteen plant and bacterial mutants that were analyzed fell into four major categories. Members of the first category of mutants formed non-functional nodules although they had differentiated nodule cells and bacteroids. This group passed the two transcriptome switch-points similarly to the wild type. The second category, which formed nodules in which the plant cells were differentiated and infected but the bacteroids did not differentiate, passed the first transcriptome switch but not the second one. Nodules in the third category contained infection threads but were devoid of differentiated symbiotic cells and displayed a root-like transcriptome. Nodules in the fourth category were free of bacteria, devoid of

  20. Gut bacteria alteration in obese people and its relationship with gene polymorphism

    Institute of Scientific and Technical Information of China (English)

    Hao-Jiang Zuo; Zhi-Mei Xie; Wei-Wei Zhang; Yong-Ru Li; Wei Wang; Xiao-Bei Ding; Xiao-Fang Pei

    2011-01-01

    AIM:To investigate the differences in cultivable gut bacteria and peroxisome proliferator-activated receptor γ2 (PPAR-γ2 ) gene Pro12Ala variation in obese and normal-weight Chinese people. METHODS:Using culture methods,the amounts of Escherichia coli ,Enterococci ,Bacteroides ,Lactobacilli ,Bifidobacteria and Clostridium perfringens (C.perfringens ) in the feces of 52 obese participants [body mass index (BMI):≥ 28 kg/m2] and 52 participants of normalweight (BMI:18.5-24 kg/m2) were obtained.Study participants completed comprehensive questionnaires and underwent clinical laboratory tests.The polymerase chain reaction-restriction fragment length polymorphism (PCR-PFLP) assay was used to analyze PPAR-γ2 gene Pro12Ala variation. RESULTS:The obese group exhibited a lower amount of C.perfringens (6.54 ± 0.65 vs 6.94 ± 0.57,P = 0.001) and Bacteroides (9.81 ± 0.58 vs 10.06 ± 0.39,P = 0.012) than their normal-weight counterparts.No major differences were observed in Pro12Ala genotype distribution between the two groups; however,obese individuals with a Pro/Ala genotype had a significantly lower level of Bacteroides (9.45 ± 0.62 vs 9.93 ± 0.51,P = 0.027) than those with a Pro/Pro genotype.In addition, the obese group demonstrated a higher stool frequency (U = 975,P < 0.001) and a looser stool (U = 1062,P = 0.015) than the normal-weight group. CONCLUSION:Our results indicated interactions among cultivable gut flora,host genetic factors and obese phenotype and this might be helpful for obesity prevention.

  1. Microbial Community of Healthy Thai Vegetarians and Non-Vegetarians, Their Core Gut Microbiota, and Pathogen Risk.

    Science.gov (United States)

    Ruengsomwong, Supatjaree; La-Ongkham, Orawan; Jiang, Jiahui; Wannissorn, Bhusita; Nakayama, Jiro; Nitisinprasert, Sunee

    2016-10-28

    Pyrosequencing analysis of intestinal microflora from healthy Thai vegetarians and non-vegetarians exhibited 893 OTUs covering 189 species. The strong species indicators of vegetarians and non-vegetarians were Prevotella copri and Bacteroides vulgatus as well as bacteria close to Escherichia hermanii with % relative abundance of 16.9 and 4.5-4.7, respectively. Core gut microbiota of the vegetarian and non-vegetarian groups consisted of 11 and 20 different bacterial species, respectively, belonging to Actinobacteria, Firmicutes, and Proteobacteria commonly found in both groups. Two species, Faecalibacterium prausnitzii and Gemmiger formicilis, had a prevalence of 100% in both groups. Three species, Clostridium nexile, Eubacterium eligens, and P. copri, showed up in most vegetarians, whereas more diversity of Collinsella aerofaciens, Ruminococcus torques, various species of Bacteroides, Parabacteroides, Escherichia, and different species of Clostridium and Eubacterium were found in most non-vegetarians. Considering the correlation of personal characters, consumption behavior, and microbial groups, the age of non-vegetarians showed a strong positive correlation coefficient of 0.54 (p = 0.001) to Bacteroides uniformis but exhibited a moderate one to Alistipes finegoldii and B. vulgatus. Only a positive moderate correlation of body mass index and Parabacteroides distasonis appeared. Based on the significant abundance of potential pathogens, the microbiota of the non-vegetarian group showed an abundance of potential pathogen varieties of Bilophila wadsworthia, Escherichia coli, and E. hermannii, whereas that of the vegetarian group served for only Klebsiella pneumoniae. These results implied that the microbiota of vegetarians with high abundance of P. copri and low potential pathogen variety would be a way to maintain good health in Thais.

  2. Protection of Sinorhizobium against host cysteine-rich antimicrobial peptides is critical for symbiosis.

    Directory of Open Access Journals (Sweden)

    Andreas F Haag

    2011-10-01

    Full Text Available Sinorhizobium meliloti differentiates into persisting, nitrogen-fixing bacteroids within root nodules of the legume Medicago truncatula. Nodule-specific cysteine-rich antimicrobial peptides (NCR AMPs and the bacterial BacA protein are essential for bacteroid development. However, the bacterial factors central to the NCR AMP response and the in planta role of BacA are unknown. We investigated the hypothesis that BacA is critical for the bacterial response towards NCR AMPs. We found that BacA was not essential for NCR AMPs to induce features of S. meliloti bacteroids in vitro. Instead, BacA was critical to reduce the amount of NCR AMP-induced membrane permeabilization and bacterial killing in vitro. Within M. truncatula, both wild-type and BacA-deficient mutant bacteria were challenged with NCR AMPs, but this resulted in persistence of the wild-type bacteria and rapid cell death of the mutant bacteria. In contrast, BacA was dispensable for bacterial survival in an M. truncatula dnf1 mutant defective in NCR AMP transport to the bacterial compartment. Therefore, BacA is critical for the legume symbiosis by protecting S. meliloti against the bactericidal effects of NCR AMPs. Host AMPs are ubiquitous in nature and BacA proteins are essential for other chronic host infections by symbiotic and pathogenic bacteria. Hence, our findings suggest that BacA-mediated protection of bacteria against host AMPs is a critical stage in the establishment of different prolonged host infections.

  3. Identification and characterization of the intracellular poly-3-hydroxybutyrate depolymerase enzyme PhaZ of Sinorhizobium meliloti

    Directory of Open Access Journals (Sweden)

    Zachertowska Alicja

    2010-03-01

    Full Text Available Abstract Background S. meliloti forms indeterminate nodules on the roots of its host plant alfalfa (Medicago sativa. Bacteroids of indeterminate nodules are terminally differentiated and, unlike their non-terminally differentiated counterparts in determinate nodules, do not accumulate large quantities of Poly-3-hydroxybutyrate (PHB during symbiosis. PhaZ is in intracellular PHB depolymerase; it represents the first enzyme in the degradative arm of the PHB cycle in S. meliloti and is the only enzyme in this half of the PHB cycle that remains uncharacterized. Results The S. meliloti phaZ gene was identified by in silico analysis, the ORF was cloned, and a S. meliloti phaZ mutant was constructed. This mutant exhibited increased PHB accumulation during free-living growth, even when grown under non-PHB-inducing conditions. The phaZ mutant demonstrated no reduction in symbiotic capacity; interestingly, analysis of the bacteroids showed that this mutant also accumulated PHB during symbiosis. This mutant also exhibited a decreased capacity to tolerate long-term carbon starvation, comparable to that of other PHB cycle mutants. In contrast to other PHB cycle mutants, the S. meliloti phaZ mutant did not exhibit any decrease in rhizosphere competitiveness; however, this mutant did exhibit a significant increase in succinoglycan biosynthesis. Conclusions S. meliloti bacteroids retain the capacity to synthesize PHB during symbiosis; interestingly, accumulation does not occur at the expense of symbiotic performance. phaZ mutants are not compromised in their capacity to compete for nodulation in the rhizosphere, perhaps due to increased succinoglycan production resulting from upregulation of the succinoglycan biosynthetic pathway. The reduced survival capacity of free-living cells unable to access their accumulated stores of PHB suggests that PHB is a crucial metabolite under adverse conditions.

  4. Microbial Source Tracking as a Tool for TMDL Development, Little Blue River in Independence, Missouri

    Science.gov (United States)

    Christensen, Eric D.; Bushon, Rebecca N.; Brady, Amie M.G.

    2013-01-01

    The Little Blue River in Jackson County, Missouri has been listed by the Missouri Department of Natural Resources as impaired by bacteria for the protection of aquatic life and contact recreation from urban point and nonpoint sources. The Clean Water Act requires that a total maximum daily load (TMDL) for Escherichia coli (E. coli) be developed. Over a 5-year period, 108 base-flow, 87 stormflow, 48 fecal source, and 12 sewage influent samples were collected and analyzed for E. coli and Bacteroides general and host-associated microbial source tracking (MST) genetic markers. Less than half of the main-stem base-flow samples exceeded the E. coli state standard, whereas, all of the stormflow samples exceeded the standard during the recreation season (April through October). Both E. coli and MST markers were detected more frequently and at higher concentrations in stormflow samples. Only 14 percent of samples with E. coli detections greater than the Missouri state standard of 206 colonies per 100 milliliters had the human-associated Bacteroides marker as the only identified marker; therefore, Little Blue River TMDL development may require a broader scope beyond the municipal separate storm sewer system if bacteria sources are to be identified and addressed. Fecal samples showed a greater specificity with the human-associated marker than the dog- or ruminant-associated Bacteroides markers; however, false positives were at least one order of magnitude lower than true positives. MST data may be a useful tool for identifying probable sources of contamination and directing TMDL strategies.

  5. More than meets the eye: associations of vaginal bacteria with gram stain morphotypes using molecular phylogenetic analysis.

    Directory of Open Access Journals (Sweden)

    Sujatha Srinivasan

    Full Text Available Bacterial vaginosis (BV is a highly prevalent condition associated with adverse health outcomes. Gram stain analysis of vaginal fluid is the standard for confirming the diagnosis of BV, wherein abundances of key bacterial morphotypes are assessed. These Lactobacillus, Gardnerella, Bacteroides, and Mobiluncus morphotypes were originally linked to particular bacterial species through cultivation studies, but no studies have systematically investigated associations between uncultivated bacteria detected by molecular methods and Gram stain findings. In this study, 16S-rRNA PCR/pyrosequencing was used to examine associations between vaginal bacteria and bacterial morphotypes in 220 women with and without BV. Species-specific quantitative PCR (qPCR and fluorescence in Situ hybridization (FISH methods were used to document concentrations of two bacteria with curved rod morphologies: Mobiluncus and the fastidious BV-associated bacterium-1 (BVAB1. Rank abundance of vaginal bacteria in samples with evidence of curved gram-negative rods showed that BVAB1 was dominant (26.1%, while Mobiluncus was rare (0.2% of sequence reads. BVAB1 sequence reads were associated with Mobiluncus morphotypes (p<0.001. Among women with curved rods, mean concentration of BVAB1 DNA was 2 log units greater than Mobiluncus (p<0.001 using species-specific quantitative PCR. FISH analyses revealed that mean number of BVAB1 cells was 2 log units greater than Mobiluncus cells in women with highest Nugent score (p<0.001. Prevotella and Porphyromonas spp. were significantly associated with the "Bacteroides morphotype," whereas Bacteroides species were rare. Gram-negative rods designated Mobiluncus morphotypes on Gram stain are more likely BVAB1. These findings provide a clearer picture of the bacteria associated with morphotypes on vaginal Gram stain.

  6. A comparative study on the effects of tylosin on select bacteria during continuous flow culture of mixed populations of gut microflora derived from a feral and a domestic pig.

    Science.gov (United States)

    Ramlachan, Nicole; Anderson, Robin C; Andrews, Kathleen; Harvey, Roger B; Nisbet, David J

    2008-02-01

    Continuous flow cultures of feral (culture FC) and domesticated (culture RPCF) pig gut microflora were established in steady state. Cultures were continuously infused with 25 or 100 microg tylosin/mL and sampled at intervals to assess effects on total culturable anaerobes, Bacteroides and Enterococcus via plating to agar supplemented without or with 100 microg tylosin/mL, the latter to assess bacterial sensitivity to tylosin. Endogenous tylosin-insensitive anaerobes within the cultures, while similar prior to tylosin administration, responded differently during tylosin administration, with concentrations in RPCF cultures becoming enriched more than in FC cultures. Tylosin-insensitive anaerobes in RPCF cultures persisted at increased concentrations after cessation of tylosin administration whereas concentrations in FC cultures decreased slightly. Concentrations of Bacteroides and endogenous Enterococcus recovered on medium without tylosin decreased to near or below detectable levels in FC cultures administered 25 or 100 microg tylosin/mL. Tylosin-insensitive Bacteroides were enriched to >5 log10 CFU/mL in RPCF cultures after 25 microg tylosin/mL but not at 100 microg tylosin/mL. Populations of endogenous tylosin-insensitive Enterococcus were enriched in RPCF but not FC cultures administered 25 or 100 microg tylosin/mL. In cultures administered 100 microg tylosin/mL, an exogenous-sourced E. faecium possessing tylosin resistance maintained itself only in the presence of tylosin. These results indicate that under the conditions of these tests, antibiotic exposure may enrich for antibiotic-insensitive bacteria populations of endogenous or exogenous origin but that the ability of an exogenous tylosin-resistant E. faecium to persist is reduced in the absence of the antibiotic, likely due to exclusion by native flora.

  7. Antibiotic selection of Escherichia coli sequence type 131 in a mouse intestinal colonization model.

    Science.gov (United States)

    Boetius Hertz, Frederik; Løbner-Olesen, Anders; Frimodt-Møller, Niels

    2014-10-01

    The ability of different antibiotics to select for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli remains a topic of discussion. In a mouse intestinal colonization model, we evaluated the selective abilities of nine common antimicrobials (cefotaxime, cefuroxime, dicloxacillin, clindamycin, penicillin, ampicillin, meropenem, ciprofloxacin, and amdinocillin) against a CTX-M-15-producing E. coli sequence type 131 (ST131) isolate with a fluoroquinolone resistance phenotype. Mice (8 per group) were orogastrically administered 0.25 ml saline with 10(8) CFU/ml E. coli ST131. On that same day, antibiotic treatment was initiated and given subcutaneously once a day for three consecutive days. CFU of E. coli ST131, Bacteroides, and Gram-positive aerobic bacteria in fecal samples were studied, with intervals, until day 8. Bacteroides was used as an indicator organism for impact on the Gram-negative anaerobic population. For three antibiotics, prolonged colonization was investigated with additional fecal CFU counts determined on days 10 and 14 (cefotaxime, dicloxacillin, and clindamycin). Three antibiotics (cefotaxime, dicloxacillin, and clindamycin) promoted overgrowth of E. coli ST131 (P organisms. Only clindamycin treatment resulted in prolonged colonization. The remaining six antibiotics, including ciprofloxacin, did not promote overgrowth of E. coli ST131 (P > 0.95), nor did they suppress Bacteroides or Gram-positive organisms. The results showed that antimicrobials both with and without an impact on Gram-negative anaerobes can select for ESBL-producing E. coli, indicating that not only Gram-negative anaerobes have a role in upholding colonization resistance. Other, so-far-unknown bacterial populations must be of importance for preventing colonization by incoming E. coli.

  8. Long-Term Survival of Fecal Indicator Bacteria in Estuarine Sediment

    Science.gov (United States)

    Ferguson, A. S.; Layton, A.; Culligan, P. J.; Kenna, T. C.; Mailloux, B. J.

    2010-12-01

    Fecal contamination of marine and freshwater environments can negatively impact water quality, leading to contaminated drinking water as well as the closure of recreational beaches and waterways. Fecal contamination is routinely assessed using fecal indicator bacteria (FIB), and even though the potential for their long-term survival or proliferation in sediments exist, information linking deposition of FIB with sediment age is scarce. We evaluate sediments as a reservoir for culturable FIB, by examining dated sediments from the lower Hudson River estuary for Escherichia coli (E. coli), enterococcus, and Bacteroides. Sediment cores were collected from in the vicinity of the George Washington (GWB) and Tappan Zee (TZB) Bridges NY. Sediment deposition ages were constrained using gamma emitting radionuclides and pollution chronology. Culturable E. coli and enterococcus were quantified using a culture-based most probable number method (ColilertTM, Idexx Laboratories). Molecular based methods were used to quantify E. coli and Bacteroides. In the GWB core, viable enterococcus or E. coli were consistently detected in sediment younger than the 1960s with maximum concentrations of 39 and 171 cells/g, respectively. In the TZB core, only enterococcus was sporadically detected in sediment younger than 1950 with a maximum concentration of 79 cells/g. Molecular Bacteroides and E. coli were detected in all core samples with a geometric mean of 4.2x104 and 1.2x105 copies/g, respectively. Results indicate that fecal bacteria can survive within estuarine sediments for decades, suggesting that sediments could be a significant and persistent source of bacterial pollution.

  9. The influence of sulbactam on the in vitro activity of mezlocillin, piperacillin and cefotaxime.

    Science.gov (United States)

    Bauernfeind, A; Grimm, H; Klietmann, W; Opferkuch, W; Werner, H

    1996-04-01

    In a multicentre study, the in-vitro activity of mezlocillin (MEZ, Chemical Abstract Service [CAS] 51481-65-3), piperacillin (PIP, CAS 61477-96-1) and cefotaxime (CTX, CAS 63527-52-6) against mezlocillin-resistant organisms was determined alone and in combination with the beta-lactamase inhibitor sulbactam (SBT, CAS 68373-14-8). A total of 870 strains were investigated (481 Enterobacteriaceae, 57 Pseudomonas aeruginosa, 41 Acinetobacter spp., 194 Bacteroides fragilis and 97 Staphylococcus spp.). MIC values were determined using the agar dilution test (aerobic organisms) or the microbroth dilution test (Bacteroides spp.) in accordance with Deutsche Industrie für Normung 58 940. SBT was added in fixed concentrations of 5 mg/l and 10 mg/l. For all combinations with SBT investigated, the geometric mean of the MIC and the MIC(50) and MIC(90) values were reduced as compared with the antibiotic alone (without SBT). Consequently, the proportion of sensitive strains was appreciably increased, for example in the Enterobacteriaceae: MEZ 1%, MEZ + 10 mg/l SBT 53%; PIP 4%, PIP + 10 mg/l SBT 54%; CTX 52%, CTX + 10 mg/l SBT 68%. The effect of SBT was especially pronounced on Bacteroides spp. For this organism, the proportion of sensitive strain rose from 2% to 97% (MEZ), 6% to 95% (PIP) and from 7% to 98% (CTX). The results show that adding SBT appreciably enhances the activity of MEZ, PIP and CTX against resistant strains of microorganism, and extends the activity spectrum to include anaerobic organisms. Thus the availability of SBT as a single-agent preparation for use in combination with various beta-lacta antibiotics represents a worthwhile enlargement of the therapeutic armamentarium for treating bacterial infections.

  10. Microbiome analysis of stool samples from African Americans with colon polyps.

    Directory of Open Access Journals (Sweden)

    Hassan Brim

    Full Text Available BACKGROUND: Colonic polyps are common tumors occurring in ~50% of Western populations with ~10% risk of malignant progression. Dietary agents have been considered the primary environmental exposure to promote colorectal cancer (CRC development. However, the colonic mucosa is permanently in contact with the microbiota and its metabolic products including toxins that also have the potential to trigger oncogenic transformation. AIM: To analyze fecal DNA for microbiota composition and functional potential in African Americans with pre-neoplastic lesions. MATERIALS & METHODS: We analyzed the bacterial composition of stool samples from 6 healthy individuals and 6 patients with colon polyps using 16S ribosomal RNA-based phylogenetic microarray; the Human intestinal Tract Chip (HITChip and 16S rRNA gene barcoded 454 pyrosequencing. The functional potential was determined by sequence-based metagenomics using 454 pyrosequencing. RESULTS: Fecal microbiota profiling of samples from the healthy and polyp patients using both a phylogenetic microarraying (HITChip and barcoded 454 pyrosequencing generated similar results. A distinction between both sets of samples was only obtained when the analysis was performed at the sub-genus level. Most of the species leading to the dissociation were from the Bacteroides group. The metagenomic analysis did not reveal major differences in bacterial gene prevalence/abundances between the two groups even when the analysis and comparisons were restricted to available Bacteroides genomes. CONCLUSION: This study reveals that at the pre-neoplastic stages, there is a trend showing microbiota changes between healthy and colon polyp patients at the sub-genus level. These differences were not reflected at the genome/functions levels. Bacteria and associated functions within the Bacteroides group need to be further analyzed and dissected to pinpoint potential actors in the early colon oncogenic transformation in a large sample size.

  11. Differential interleukin-10 (IL-10) and IL-23 production by human blood monocytes and dendritic cells in response to commensal enteric bacteria.

    Science.gov (United States)

    Manuzak, Jennifer; Dillon, Stephanie; Wilson, Cara

    2012-08-01

    Human peripheral blood contains antigen-presenting cells (APC), including dendritic cells (DC) and monocytes, that may encounter microbes that have translocated from the intestine to the periphery in disease states like HIV-1 infection and inflammatory bowel disease. We investigated the response of DC and monocytes in peripheral blood mononuclear cells (PBMC) to a panel of representative commensal enteric bacteria, including Escherichia coli, Enterococcus sp., and Bacteroides fragilis. All three bacteria induced significant upregulation of the maturation and activation markers CD40 and CD83 on myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC). However, only mDC produced cytokines, including interleukin-10 (IL-10), IL-12p40/70, and tumor necrosis factor alpha (TNF-α), in response to bacterial stimulation. Cytokine profiles in whole PBMC differed depending on the stimulating bacterial species: B. fragilis induced production of IL-23, IL-12p70, and IL-10, whereas E. coli and Enterococcus induced an IL-10-predominant response. mDC and monocyte depletion experiments indicated that these cell types differentially produced IL-10 and IL-23 in response to E. coli and B. fragilis. Bacteroides thetaiotaomicron did not induce levels of IL-23 similar to those of B. fragilis, suggesting that B. fragilis may have unique proinflammatory properties among Bacteroides species. The addition of recombinant human IL-10 to PBMC cultures stimulated with commensal bacteria abrogated the IL-23 response, whereas blocking IL-10 significantly enhanced IL-23 production, suggesting that IL-10 controls the levels of IL-23 produced. These results indicate that blood mDC and monocytes respond differentially to innate stimulation with whole commensal bacteria and that IL-10 may play a role in controlling the proinflammatory response to translocated microbes.

  12. 琥珀酸对中性粒细胞的抑制作用%Succinic acid inhibits polymorphonuclear leukocyte's function

    Institute of Scientific and Technical Information of China (English)

    任利成; 黄晓元; 龙剑虹

    2004-01-01

    Objective:To examine the effect of succinic acid on the function of human polymorphonuclear(PMN)leukocyte and it's special function as a virulent factor of Bacteroides Fragilis.Methods:PMN wasseperated from the blood of healthy donors,incubated with succinic acid at the concentration of 5,10,20 and 30 mmol/L for 20 min or at the concentration of 20 mmol/L for 5,10 15 and 20 min.Tested PMN's power of adherence and deoxidizing NBT.Results:Succinic acid can inhibit PMN's power of adherence and deoxidization,the inhibitory action was related to the time of incubation and succinic acid's concentration.Conclusions:Succinic acid can inhibit PMN's function and it may be an important virulent factor to Bacteroides Fragilis.%目的探讨脆弱类杆菌代谢产物琥珀酸(succinic acid)对中性粒细胞(polymorphonuclear,PMN)功能的影响及其在脆弱类杆菌(bacteroides fragilis)发病中的作用.方法体外分离外周血PMN,以5,10,20,30 nmol/L四种浓度的琥珀酸分别孵育20 min,或以20 mmol/L浓度的琥珀酸孵育5,10,15和20 min,测定对PMN粘附率(adherencerate)及硝基蓝四氮唑(NBT)还原能力的影响.结果琥珀酸能显著抑制PMN粘附率及NBT还原能力,且呈浓度,时间依赖关系.结论琥珀酸能抑制PMN的功能,在脆弱类杆菌的发病中占有重要的作用.

  13. Pleiotropic effects of a rel mutation on stress survival of Rhizobium etli CNPAF512

    Directory of Open Access Journals (Sweden)

    Beullens Serge

    2008-12-01

    Full Text Available Abstract Background The rel gene of Rhizobium etli (relRet, the nodulating endosymbiont of the common bean plant, determines the cellular level of the alarmone (pppGpp and was previously shown to affect free-living growth and symbiosis. Here, we demonstrate its role in cellular adaptation and survival in response to various stresses. Results Growth of the R. etli relRet mutant was strongly reduced or abolished in the presence of elevated NaCl levels or at 37°C, compared to the wild type. In addition, depending on the cell density, decreased survival of exponentially growing or stationary phase relRet mutant cells was obtained after H2O2, heat or NaCl shock compared to the wild-type strain. Survival of unstressed stationary phase cultures was differentially affected depending on the growth medium used. Colony forming units (CFU of relRet mutant cultures continuously decreased in minimal medium supplemented with succinate, whereas wild-type cultures stabilised at higher CFU levels. Microscopic examination of stationary phase cells indicated that the relRet mutant was unable to reach the typical coccoid morphology of the wild type in stationary phase cultures. Assessment of stress resistance of re-isolated bacteroids showed increased sensitivity of the relRet mutant to H2O2 and a slightly increased resistance to elevated temperature (45°C or NaCl shock, compared to wild-type bacteroids. Conclusion The relRet gene is an important factor in regulating rhizobial physiology, during free-living growth as well as in symbiotic conditions. Additionally, differential responses to several stresses applied to bacteroids and free-living exponential or stationary phase cells point to essential physiological differences between the different states.

  14. INFLUENCIA DE LA SEQUÍA SOBRE EL METABOLISMO DEL NITRÓGENO FIJADO DURANTE LA SIMBIOSIS Bradyrhizobium-SOYA

    OpenAIRE

    J. A. Freixas; Inés M. Reynaldo; María C. Nápoles

    2010-01-01

    La soya (Glycine max L. Merr.) establece simbiosis con bacterias fijadoras del nitrógeno de la familia de los rizobios; específicamente con bacterias del género Bradyrhizobium. Los rizobios secretan moléculas específicas denominadas factores Nod, que juegan un papel importante en el desarrollo del nódulo radicular. En el nódulo, los rizobios son diferenciados en bacteroides, donde ocurre la fijación biológica del nitrógeno (BNF) y se produce amonio. La mayor parte del amonio es asimilado en g...

  15. Eikenella corrodens: Patogénesis y aspectos clínicos

    OpenAIRE

    Rubén Darío Jaramillo; Paola Suárez; Beatriz Barraza; Paulina Lara; Luis Teherán; José Edgardo Escamilla

    2006-01-01

    El ambiente microbiológico oral es único y tiene una dinámica compleja. Se calcula que cerca de 500 especies de bacterias habitan la cavidad oral humana, y alrededor de 22 géneros son los predominantes. Las bacterias que se aíslan con más frecuencia de los sitios infectados de la cavidad oral, y que son también patógenos potenciales, forma un grupo pequeño de microorganismos gramnegativos, entre los que se incluyen los siguientes: Actinobacillus actinomycetemcomitans, Bacteroides forsythus, C...

  16. Methane and hydrogen production by human intestinal anaerobic bacteria.

    Science.gov (United States)

    McKay, L F; Holbrook, W P; Eastwood, M A

    1982-06-01

    The gas above liquid cultures of a variety of human intestinal anaerobic bacteria was sampled and analysed by headspace gas chromatography. Hydrogen production was greatest with strains of the genus Clostridium, intermediate with anaerobic cocci and least with Bacteroides sp. Very few strains produced methane although small amounts were detected with one strain of B. thetaiotaomicron, C. perfringens and C. histolyticum. There may be a relationship between these anaerobic bacteria and several gastrointestinal disorders in which there is a build up of hydrogen or methane in the intestines.

  17. Eficacia y mecanismos de acción de bacterias intestinales en alteraciones metabólicas e inmunológicas asociadas a la obesidad y al estrés

    OpenAIRE

    Moya Perez, Angela

    2015-01-01

    El objetivo general de la presente Tesis ha sido analizar la contribución de la microbiota intestinal a la función del sistema inmune, metabolismo, Sistema Nervioso Central y evaluar el efecto de potenciales probióticos en modelos animales de obesidad y ansiedad inducida por estrés. Los objetivos concretos han sido los siguientes: 1. Evaluar la eficacia de Bacteroides uniformis CECT 7771 en un modelo murino de obesidad inducida por la dieta. 2. Identificar el mecanismo de acción d...

  18. Rhizobium meliloti and Rhizobium leguminosarum dctD gene products bind to tandem sites in an activation sequence located upstream of sigma 54-dependent dctA promoters.

    OpenAIRE

    Ledebur, H; Gu, B.; Sojda, J; Nixon, B T

    1990-01-01

    Free-living rhizobia transport external C4-dicarboxylates to use as sole carbon sources, and uptake of these compounds is essential for nitrogen fixation by rhizobial bacteroids. In both Rhizobium leguminosarum and Rhizobium meliloti, the genes dctB and dctD are believed to form an ntrB/ntrC-like two-component system which regulates the synthesis of a C4-dicarboxylate transport protein encoded by dctA. Here we confirm the identity of sigma 54-dependent promoters previously hypothesized for th...

  19. Risks Associated with High-Dose Lactobacillus rhamnosus in an Escherichia coli Model of Piglet Diarrhoea

    DEFF Research Database (Denmark)

    Li, Xiao-Qiong; Zhu, Yao-Hong; Zhang, Hong-Fu

    2012-01-01

    detected by ELISA and immunohistochemistry, respectively. Unexpectedly, high-dose administration increased the incidence of diarrhoea before F4+ETEC challenge, despite the fact that both doses ameliorated F4+ETEC-induced diarrhoea with increased Lactobacillus and Bifidobacterium counts accompanied...... by reduced coliform shedding in faeces. Interestingly, L. rhamnosus administration reduced Lactobacillus and Bifidobacterium counts in the colonic contents, and the high-dose piglets also had lower Lactobacillius and Bacteroides counts in the ileal contents. An increase in the concentration of serum TNF...

  20. Effects of selected non-digestible dietary carbohydrates on the composition of the large intestinal microbiota and susceptibility to salmonella infections

    DEFF Research Database (Denmark)

    Petersen, Anne

    in the faecal microbiota including an increase in the Bacteroidetes phylum, the Bacteroides fragilis group and in Bifidobacterium spp., while reductions were observed in the Firmicutes phylum and the Clostridium coccoides group. The findings thus suggest that some microbial changes in the large intestine may...... in the C. coccoides group. Other microbial changes observed, including a reduction in Bifidobacterium spp. and sulphate-reducing bacteria, suggest that quantities of some bacterial species are related to changes in faecal water genotoxicity. Conclusively, the studies contribute to our knowledge...

  1. Introduction of the Escherichia coli gdhA gene into Rhizobium phaseoli: effect on nitrogen fixation.

    Science.gov (United States)

    Bravo, A; Becerril, B; Mora, J

    1988-01-01

    Rhizobium phaseoli lacks glutamate dehydrogenase (GDH) and assimilates ammonium by the glutamine synthetase-glutamate synthase pathway. A strain of R. phaseoli harboring the Escherichia coli GDH structural gene (gdhA) was constructed. GDH activity was expressed in R. phaseoli in the free-living state and in symbiosis. Nodules with bacteroids that expressed GDH activity had severe impairment of nitrogen fixation. Also, R. phaseoli cells that lost GDH activity and assimilated ammonium by the glutamine synthetase-glutamate synthase pathway preferentially nodulated Phaseolus vulgaris. PMID:2892830

  2. STUDY OF AEROBIC AND ANAEROBIC BACTERIA IN CHRONIC SUPPURATIVE OTITIS MEDIA

    Directory of Open Access Journals (Sweden)

    Satyanarayana

    2015-04-01

    Full Text Available One hundred six patients with clinical diagnosis of CSOM were investigated bacteriologically using appropriate aerobic and anaerobic techniques. Positive cultures were obtained in 100 specimens. Aerobic bacteria alone were present in 51%, anaerobic bacteria alone in 10% and a combination of both in 34% of aural swabs . The anaerobes isolated were Bacteroides 30%, Peptostreptococci 26%, followed by others. Aerobic bacteriology showed the predominance of Pseudomonas 30.4% followed by Staphylococcus aureus 21.4%. Metronidazole was found to be most effective (87% drug aga inst anaerobes and Amikacin (98% against aerobes.

  3. Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria.

    Science.gov (United States)

    1976-01-15

    Peptococcus micros 5.8 Fusobacterium varium 5.2 Clostridium sartagoformum 5.2 Clostridium tyrobutyricum 5.0 Bacteriological studies were also performed on...4.5 Non-sooreforming Gram- Corynebacterium sp. 4.4 positive rod 6.3 c-hemolytic streptococcus 4.0 Clostridium perfringens 6.1 Proteus mirabilis 4.0... Clostridium paraputrificum 6.0 Proteus morganii 3.9 Clostridium species 6.0 Moraxella sp. 3.1 Bacteroides fragilis 5.8 Peptococcus morbillorum 5.7

  4. [Appendiceal peritonitis in childhood, antibiotic treatment with cefoxitin].

    Science.gov (United States)

    Aristegui, J; de la Fuente, E; Pérez Legorburu, A; de Gárate, J

    1982-11-01

    Twenty one cases of appendiceal peritonitis in children are reviewed. An antibiotic (sodium cefoxitine) has been used during the post-operative course to decrease the risk of suppurative complications. Cultures obtained from peritoneal exudate yielded "E. coli" and "Bacteroides" sp. as the most commonly isolated bacteria. External drainage was placed as a rutine and the percentage of suppurative complications was 14%. No patient showed evidence of adverse reactions to the antibiotic and the mortality of the serie was zero. Obtained results allow to state that cefoxitine is effective in the management of appendiceal peritonitis in children.

  5. Influence of age and immunization on development of gingivitis in rats

    DEFF Research Database (Denmark)

    Lekic, P; Klausen, B; Friis-Hasché, E

    1989-01-01

    To study the effect of age and antigenic priming on the development of gingivitis, 33 healthy rats were placed in contact with Streptococcus mutans, Actinomyces viscosus, Fusobacterium nucleatum, and Bacteroides gingivalis. On days 0, 3, 7, and 14 after inoculation, the gingival condition...... was judged clinically and histologically, and serum antibody titers against the bacteria were measured. The rats were divided into three groups: 1 month old, 3 months old, and 3 months old immunized. None of the young rats developed gingivitis during the experiment, whereas half of the adult and all...

  6. Diet shapes the ability of human intestinal microbiota to degrade phytate - in vitro studies

    OpenAIRE

    Markiewicz, L. H.; Honke, J.; Haros, Monika; Swiatecka, D.; Wróblewska, B.

    2013-01-01

    Aims: Investigation of intestinal bacterial groups involved in phytate degradation and the impact of diets with different phytate contents on phytase activity. Methods and Results: Faecal samples of adults on conventional (n = 8) or vegetarian (n = 8) diets and breastfed infants (n = 6) were used as an inoculum for modified media supplemented with phytate. Populations of Gram-positive anaerobes (GPA), lactic acid bacteria (LAB), Proteobacteria-Bacteroides (P-B), coliforms and anaerobes were s...

  7. Tracking heavy water (D2O) incorporation for identifying and sorting active microbial cells

    DEFF Research Database (Denmark)

    Berry, David; Mader, Esther; Lee, Tae Kwon;

    2015-01-01

    peaks in single-cell Raman spectra, and the obtained labeling pattern was confirmed by nanoscaleresolution secondary ion MS. In fast-growing Escherichia coli cells, label detection was already possible after 20 min. For functional analyses of microbial communities, the detection of D incorporation from...... D2O in individual microbial cells via Raman microspectroscopy can be directly combined with FISH for the identification of active microbes. Applying this approach to mouse cecal microbiota revealed that the host-compound foragers Akkermansia muciniphila and Bacteroides acidifaciens exhibited...

  8. Phylogenetic analysis of bacteria in sea ice brine sampled from the Canada Basin, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Bacterial diversity in sea ice brine samples which collected from four stations located at the Canada Basin, Arctic Ocean was analyzed by PCR-DGGE. Twenty-three 16S rDNA sequences of bacteria obtained from DGGE bands were cloned and sequenced. Phylogenetic analysis clustered these sequences within γ-proteobacteria, Cytophaga-Flexibacter-Bacteroides (CFB) group, Firmicutes and Actinobacteria. The phylotype of Pseudoalteromonas in the γ-proteobacteria was predominant and members of the CFB group and γ-proteobacteria were highly abundant in studied sea ice brine samples.

  9. Tissue-associated bacterial alterations in rectal carcinoma patients revealed by 16S rRNA community profiling

    Directory of Open Access Journals (Sweden)

    Andrew Maltez Thomas

    2016-12-01

    Full Text Available Sporadic and inflammatory forms of colorectal cancer (CRC account for more than 80% of cases. Recent publications have shown mechanistic evidence for the involvement of gut bacteria in the development of both CRC-forms. Whereas colon and rectal cancer have been routinely studied together as CRC, increasing evidence show these to be distinct diseases. Also, the common use of fecal samples to study microbial communities may reflect disease state but possibly not the tumor microenvironment. We performed this study to evaluate differences in bacterial communities found in tissue samples of 18 rectal-cancer subjects when compared to 18 non-cancer controls. Samples were collected during exploratory colonoscopy (non-cancer group or during surgery for tumor excision (rectal-cancer group. High throughput 16S rRNA amplicon sequencing of the V4-V5 region was conducted on the Ion PGM platform, reads were filtered using Qiime and clustered using UPARSE. We observed significant increases in species richness and diversity in rectal cancer samples, evidenced by the total number of OTUs and the Shannon and Simpson indexes. Enterotyping analysis divided our cohort into two groups, with the majority of rectal cancer samples clustering into one enterotype, characterized by a greater abundance of Bacteroides and Dorea. At the phylum level, rectal-cancer samples had increased abundance of candidate phylum OD1 (also known as Parcubacteria whilst non-cancer samples had increased abundance of Planctomycetes. At the genera level, rectal-cancer samples had higher abundances of Bacteroides, Phascolarctobacterium, Parabacteroides, Desulfovibrio and Odoribacter whereas non-cancer samples had higher abundances of Pseudomonas, Escherichia, Acinetobacter, Lactobacillus and Bacillus. Two Bacteroides fragilis OTUs were more abundant among rectal-cancer patients seen through 16S rRNA amplicon sequencing, whose presence was confirmed by immunohistochemistry and enrichment verified

  10. Isolation of Rhizobium phaseoli Tn5-induced mutants with altered expression of cytochrome terminal oxidases o and aa3.

    Science.gov (United States)

    Soberón, M; Membrillo-Hernández, J; Aguilar, G R; Sánchez, F

    1990-01-01

    Two Rhizobium phaseoli mutants affected in cytochrome expression were obtained by Tn5-mob mutagenesis of the wild-type strain (CE3). Mutant strain CFN031 expressed sevenfold less cytochrome o in culture, expressed cytochrome aa3 under microaerophilic culture conditions, in contrast to strain CE3, and was affected in its vegetative growth properties and proliferation inside plant host cells. Mutant CFN037 expressed cytochrome aa3 under microaerophilic culture conditions, while bacteroid development and nitrogen fixation occurred earlier than in strain CE3. Images FIG. 2 PMID:2155209

  11. [Significance of deficient bacterial colonization in the pathogenesis of mucosal lesions in experimental blind loop syndrome].

    Science.gov (United States)

    Menge, H; Germer, C T; Stössel, R; Simes, G; Wagner, J; Hahn, H; Riecken, E O

    1985-07-20

    A complete evaluation of the bacterial flora in jejunal self-filling blind loops was performed. The results show a significant increase in bacteria of the genera E. coli, Streptococcus and Bacteroides. In further experiments, jejunal self-filling blind loops were created in germ-free animals. In spite of the germ-free state the mucosa displayed marked hyperplasia. The same was true when the blind loops had been contaminated with aerobic bacteria. These results demonstrate that other factors in addition to bacterial overgrowth contribute to the mucosal damage observed in self-filling blind loops.

  12. Bacterial populations and metabolites in the feces of free roaming and captive grizzly bears.

    Science.gov (United States)

    Schwab, Clarissa; Cristescu, Bogdan; Boyce, Mark S; Stenhouse, Gordon B; Gänzle, Michael

    2009-12-01

    Gut physiology, host phylogeny, and diet determine the composition of the intestinal microbiota. Grizzly bears (Ursus arctos horribilis) belong to the Order Carnivora, yet feed on an omnivorous diet. The role of intestinal microflora in grizzly bear digestion has not been investigated. Microbiota and microbial activity were analysed from the feces of wild and captive grizzly bears. Bacterial composition was determined using culture-dependent and culture-independent methods. The feces of wild and captive grizzly bears contained log 9.1 +/- 0.5 and log 9.2 +/- 0.3 gene copies x g(-1), respectively. Facultative anaerobes Enterobacteriaceae and enterococci were dominant in wild bear feces. Among the strict anaerobes, the Bacteroides-Prevotella-Porphyromonas group was most prominent. Enterobacteriaceae were predominant in the feces of captive grizzly bears, at log 8.9 +/- 0.5 gene copies x g(-1). Strict anaerobes of the Bacteroides-Prevotella-Porphyromonas group and the Clostridium coccoides cluster were present at log 6.7 +/- 0.9 and log 6.8 +/- 0.8 gene copies x g(-1), respectively. The presence of lactate and short-chain fatty acids (SCFAs) verified microbial activity. Total SCFA content and composition was affected by diet. SCFA composition in the feces of captive grizzly bears resembled the SCFA composition of prey-consuming wild animals. A consistent data set was obtained that associated fecal microbiota and metabolites with the distinctive gut physiology and diet of grizzly bears.

  13. Endophytic bacterial diversity in roots of Typha angustifolia L. in the constructed Beijing Cuihu Wetland (China).

    Science.gov (United States)

    Li, Yan Hong; Liu, Qun Fang; Liu, Yin; Zhu, Jing Nan; Zhang, Qiang

    2011-01-01

    We investigated the community structure of endophytic bacteria in narrowleaf cattail (Typha angustifolia L.) roots growing in the Beijing Cuihu Wetland, China, using the 16S rDNA library technique. In total, 184 individual sequences were used to assess the diversity of endophytic bacteria. Phylogenetic analysis revealed that 161 clones (87.5%) were affiliated with Proteobacteria, other clones grouped into Cytophaga/Flexibacter/Bacteroids (3.3%), Fusobacteria (3.8%), and nearly 5% were uncultured bacteria. In Proteobacteria, the beta and gamma subgroups were the most abundant, accounting for approximately 46% and 36.6% of all Proteobacteria, respectively. The dominant genera included Rhodoferax, Pelomonas, Uliginosibacterium, Pseudomonas, Aeromonas, Rhizobium, Sulfurospirillum, Ilyobacter and Bacteroides. While some of these endophytic bacteria are capable of fixing nitrogen and can therefore improve plant growth, other endophytes may play important biological roles by removing nitrogen, phosphorus and/or organic matter from the water body and thus have the potential to enhance the phytoremediation of eutrophic water bodies. These bacteria have the potential to degrade xenobiota such as methane, methanol, methylated amines, catechol, oxochlorate, urea, cyanide, and 2,4-dichlorophenol. Hence, the use of certain endophytic bacteria in the process of phytoremediation could be a powerful approach for the restoration of eutrophic systems.

  14. Molecular cloning, functional characterization, and subcellular localization of soybean nodule dihydrolipoamide reductase.

    Science.gov (United States)

    Moran, Jose F; Sun, Zhaohui; Sarath, Gautam; Arredondo-Peter, Raúl; James, Euan K; Becana, Manuel; Klucas, Robert V

    2002-01-01

    Nodule ferric leghemoglobin reductase (FLbR) and leaf dihydrolipoamide reductase (DLDH) belong to the same family of pyridine nucleotide-disulfide oxidoreductases. We report here the cloning, expression, and characterization of a second protein with FLbR activity, FLbR-2, from soybean (Glycine max) nodules. The cDNA is 1,779 bp in length and codes for a precursor protein comprising a 30-residue mitochondrial transit peptide and a 470-residue mature protein of 50 kD. The derived protein has considerable homology with soybean nodule FLbR-1 (93% identity) and pea (Pisum sativum) leaf mitochondria DLDH (89% identity). The cDNA encoding the mature protein was overexpressed in Escherichia coli. The recombinant enzyme showed Km and kcat values for ferric leghemoglobin that were very similar to those of DLDH. The transcripts of FLbR-2 were more abundant in stems and roots than in nodules and leaves. Immunoblots of nodule fractions revealed that an antibody raised against pea leaf DLDH cross-reacted with recombinant FLbR-2, native FLbR-2 of soybean nodule mitochondria, DLDH from bacteroids, and an unknown protein of approximately 70 kD localized in the nodule cytosol. Immunogold labeling was also observed in the mitochondria, cytosol, and bacteroids of soybean nodules. The similar biochemical, kinetic, and immunological properties, as well as the high amino acid sequence identity and mitochondrial localization, draw us to conclude that FLbR-2 is soybean DLDH.

  15. The currently used commercial DNA-extraction methods give different results of clostridial and actinobacterial populations derived from human fecal samples.

    Science.gov (United States)

    Maukonen, Johanna; Simões, Catarina; Saarela, Maria

    2012-03-01

    Recently several human health-related microbiota studies have had partly contradictory results. As some differences may be explained by methodologies applied, we evaluated how different storage conditions and commonly used DNA-extraction kits affect bacterial composition, diversity, and numbers of human fecal microbiota. According to our results, the DNA-extraction did not affect the diversity, composition, or quantity of Bacteroides spp., whereas after a week's storage at -20 °C, the numbers of Bacteroides spp. were 1.6-2.5 log units lower (P DNA-extraction as detected with qPCR, regardless of storage. Furthermore, the bacterial composition of Erec-group differed significantly after different DNA-extractions; after enzymatic DNA-extraction, the most prevalent genera detected were Roseburia (39% of clones) and Coprococcus (10%), whereas after mechanical DNA-extraction, the most prevalent genera were Blautia (30%), Coprococcus (13%), and Dorea (10%). According to our results, rigorous mechanical lysis enables detection of higher bacterial numbers and diversity from human fecal samples. As it was shown that the results of clostridial and actinobacterial populations are highly dependent on the DNA-extraction methods applied, the use of different DNA-extraction protocols may explain the contradictory results previously obtained.

  16. Multiple Ku orthologues mediate DNA non-homologous end-joining in the free-living form and during chronic infection of Sinorhizobium meliloti.

    Science.gov (United States)

    Kobayashi, Hajime; Simmons, Lyle A; Yuan, Daniel S; Broughton, William J; Walker, Graham C

    2008-01-01

    The bacterial non-homologous end-joining (NHEJ) apparatus is a two-component system that uses Ku and LigD to repair DNA double-strand breaks. Although the reaction mechanism has been extensively studied, much less is known about the physiological role of bacterial NHEJ. Recent studies suggest that NHEJ acts under conditions where DNA replication is reduced or absent (such as in a spore or stationary phase). Interestingly, genes encoding Ku and LigD have been identified in a wide range of bacteria that can chronically infect eukaryotic hosts. Strikingly, Sinohizobium meliloti, an intracellular symbiont of legume plants, carries four genes encoding Ku homologues (sku1 to sku4). Deletion analysis of the sku genes indicated that all Ku homologues are functional. One of these genes, sku2, is strongly expressed in free-living cells, as well as in bacteroid cells residing inside of the host plant. To visualize the NHEJ apparatus in vivo, SKu2 protein was fused to yellow fluorescent protein (YFP). Ionizing radiation (IR) induced focus formation of SKu2-YFP in free-living cells in a dosage-dependent manner. Moreover, SKu2-YFP foci formed in response to IR in non-dividing bacteroids, indicating that NHEJ system is functional even during the chronic infection phase of symbiosis.

  17. [Microbial ecology of the intestines in health and in pathology].

    Science.gov (United States)

    Goncharova, G I; Dorofeĭchuk, V G; Smolianskaia, A Z; Sokolova, K Ia

    1989-06-01

    Bifidoflora constitute 85--95 per cent of the large intestine microbiocenosis in children under 1 year of age. Bacteroides are not specific of children under 6 months of age. Lactobacilli, lactic acid streptococci, colon bacilli, enterococci and staphylococci (saprophytic, epidermal) constitute not more than 15 per cent. The predominating group peculiar of eubiosis in adults includes bifidobacteria and bacteroides. Changes in human autoflora are often induced by such factors as impaired ecology, stress, uncontrolled use of antibacterial drugs, radio- and chemotherapy, etc. Dysbacteriosis (first of all lower quantitative contents of bifidoflora) has an unfavourable effect on the intestine secretory function, absorption and certain indices of protein, lipid and mineral metabolism, vitamin synthesizing and fermentative functions and leads to disfunction of the gastrointestinal tract. It is a cause of persisting and relapsing infections in children and adults. High and optimal levels of bifidoflora in the intestine usually prevent the pathogenic action of pathogens. Lysozyme of digestive secretion and secretory immunity with immunoglobulin A prevalence also play an important role in the complicated mechanism of the protective barrier. The use of bacterial preparations such as bifidumbacterin, lactobacterin or bifilact for stabilization and recovery of high bifidoflora levels is indicated in all the cases with impaired microbiocenosis of the intestine.

  18. Characterization of the urease gene cluster from Rhizobium leguminosarum bv. viciae.

    Science.gov (United States)

    Toffanin, Annita; Cadahia, Esther; Imperial, Juan; Ruiz-Argüeso, Tomás; Palacios, Manuel

    2002-04-01

    Moderate levels of urease activity (ca. 300 mU mg(-1)) were detected in Rhizobium leguminosarum bv. viciae UPM791 vegetative cells. This activity did not require urea for induction and was partially repressed by the addition of ammonium into the medium. Lower levels of urease activity (ca. 100 mU mg(-1)) were detected also in pea bacteroids. A DNA region of ca. 9 kb containing the urease structural genes ( ureA, ureB and ureC), accessory genes ( ureD, ureE, ureF, and ureG), and five additional ORFs ( orf83, orf135, orf207, orf223, and orf287) encoding proteins of unknown function was sequenced. Three of these ORFs ( orf83, orf135 and orf207) have a homologous counterpart in a gene cluster from Sinorhizobium meliloti, reported to be involved in urease and hydrogenase activities. R. leguminosarum mutant strains carrying Tn 5 insertions within this region exhibited a urease-negative phenotype, but induced wild-type levels of hydrogenase and nitrogenase activities in bacteroids. orf287 encodes a potential transmembrane protein with a C-terminal GGDEF domain. A mutant affected in orf287 exhibited normal levels of urease activity in culture cells. Experiments aimed at cross-complementing Ni-binding proteins required for urease and hydrogenase synthesis (UreE and HypB, respectively) indicated that these two proteins are not functionally interchangeable in R. leguminosarum.

  19. Comparative cytotoxicity of periodontal bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, R.H.; Hammond, B.F.

    1988-11-01

    The direct cytotoxicity of sonic extracts (SE) from nine periodontal bacteria for human gingival fibroblasts (HGF) was compared. Equivalent dosages (in terms of protein concentration) of SE were used to challenge HGF cultures. The cytotoxic potential of each SE was assessed by its ability to (1) inhibit HGF proliferation, as measured by direct cell counts; (2) inhibit 3H-thymidine incorporation in HGF cultures; or (3) cause morphological alterations of the cells in challenged cultures. The highest concentration (500 micrograms SE protein/ml) of any of the SEs used to challenge the cells was found to be markedly inhibitory to the HGFs by all three of the criteria of cytotoxicity. At the lowest dosage tested (50 micrograms SE protein/ml); only SE from Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Fusobacterium nucleatum caused a significant effect (greater than 90% inhibition or overt morphological abnormalities) in the HGFs as determined by any of the criteria employed. SE from Capnocytophaga sputigena, Eikenella corrodens, or Wolinella recta also inhibited cell proliferation and thymidine incorporation at this dosage; however, the degree of inhibition (5-50%) was consistently, clearly less than that of the first group of three organisms named above. The SE of the three other organisms tested (Actinomyces odontolyticus, Bacteroides intermedius, and Streptococcus sanguis) had little or no effect (0-10% inhibition) at this concentration. The data suggest that the outcome of the interaction between bacterial components and normal resident cells of the periodontium is, at least in part, a function of the bacterial species.

  20. The phylogenetic relationships of Caulobacter, Asticcacaulis and Brevundimonas species and their taxonomic implications.

    Science.gov (United States)

    Sly, L I; Cox, T L; Beckenham, T B

    1999-04-01

    The phylogenetic relationships among the species of Caulobacter, Asticcacaulis and Brevundimonas were studied by comparison of their 16S rDNA sequences. The analysis of almost complete sequences confirmed the early evolutionary divergence of the freshwater and marine species of Caulobacter reported previously [Stahl, D. A., Key, R., Flesher, B. & Smit, J. (1992). J Bacteriol 174, 2193-2198]. The freshwater species formed two distinct clusters. One cluster contained the species Caulobacter bacteroides, Caulobacter crescentus, Caulobacter fusiformis and Caulobacter henricii. C. bacteroides and C. fusiformis are very closely related (sequence identity 99.8%). The second cluster was not exclusive and contained the specis Caulobacter intermedius, Caulobacter subvibrioides and Caulobacter variabilis, as well as Brevundimonas diminuta and Brevundimonas vesicularis. The marine species Caulobacter halobacteroides and Caulobacter maris were very closely related, with a sequence identity of 99.7%. These two species were most closely but distantly related to the marine hyphal/budding bacteria Hyphomonas jannaschiana and Hirschia baltica, which formed a deep phylogenetic line with Rhodobacter sphaeroides and Rhodobacter capsulatus. Caulobacter leidyia is unrelated to the other species of Caulobacter and belongs to the alpha-4 subclass of the Proteobacteria, forming a distinct cluster with Asticcacaulis excentricus and Asticcacaulis biprosthecium. The taxonomic implications of the polyphyletic nature of the genus Caulobacter and the absence of a type culture for the type species of the genus Caulobacter vibrioides, are discussed.

  1. Comparative study on the in vitro effects of Pseudomonas aeruginosa and seaweed alginates on human gut microbiota.

    Science.gov (United States)

    Bai, Shaofeng; Chen, Huahai; Zhu, Liying; Liu, Wei; Yu, Hongwei D; Wang, Xin; Yin, Yeshi

    2017-01-01

    Alginates pertain to organic polysaccharides that have been extensively used in food- and medicine-related industries. The present study obtained alginates from an alginate overproducing Pseudomonas aeruginosa PAO1 mutant by screening transposon mutagenesis libraries. The interaction between bacterial and seaweed alginates and gut microbiota were further studied by using an in vitro batch fermentation system. Thin-layer chromatography (TLC) analysis indicated that both bacterial and seaweed alginates can be completely degraded by fecal bacteria isolated from study volunteers, indicating that a minor structural difference between bacterial and seaweed alginates (O-acetylation and lack of G-G blocks) didn't affect the digestion of alginates by human microbiota. Although, the digestion of bacterial and seaweed alginates was attributed to different Bacteroides xylanisolvens strains, they harbored similar alginate lyase genes. Genus Bacteroides with alginate-degrading capability were enriched in growth medium containing bacterial or seaweed alginates after in vitro fermentation. Short-chain fatty acid (SCFA) production in both bacterial and seaweed alginates was also comparable, but was significantly higher than the same medium using starch. In summary, the present study has isolated an alginate-overproducing P. aeruginosa mutant strain. Both seaweed and bacterial alginates were degraded by human gut microbiota, and their regulatory function on gut microbiota was similar.

  2. Molecular analysis of gut microbiota in obesity among Indian individuals

    Indian Academy of Sciences (India)

    Deepak P Patil; Dhiraj P Dhotre; Sachin G Chavan; Armiya Sultan; Dhawal S Jain; Vikram B Lanjekar; Jayshree Gangawani; Poonam S Shah; Jayshree S Todkar; Shashank Shah; Dilip R Ranade; Milind S Patole; Yogesh S Shouche

    2012-09-01

    Obesity is a consequence of a complex interplay between the host genome and the prevalent obesogenic factors among the modern communities. The role of gut microbiota in the pathogenesis of the disorder was recently discovered; however, 16S-rRNA-based surveys revealed compelling but community-specific data. Considering this, despite unique diets, dietary habits and an uprising trend in obesity, the Indian counterparts are poorly studied. Here, we report a comparative analysis and quantification of dominant gut microbiota of lean, normal, obese and surgically treated obese individuals of Indian origin. Representative gut microbial diversity was assessed by sequencing fecal 16S rRNA libraries for each group (n=5) with a total of over 3000 sequences. We detected no evident trend in the distribution of the predominant bacterial phyla, Bacteroidetes and Firmicutes. At the genus level, the bacteria of genus Bacteroides were prominent among the obese individuals, which was further confirmed by qPCR ( > 0.05). In addition, a remarkably high archaeal density with elevated fecal SCFA levels was also noted in the obese group. On the contrary, the treated-obese individuals exhibited comparatively reduced Bacteroides and archaeal counts along with reduced fecal SCFAs. In conclusion, the study successfully identified a representative microbial diversity in the Indian subjects and demonstrated the prominence of certain bacterial groups in obese individuals; nevertheless, further studies are essential to understand their role in obesity.

  3. A vapBC-type toxin-antitoxin module of Sinorhizobium meliloti influences symbiotic efficiency and nodule senescence of Medicago sativa.

    Science.gov (United States)

    Lipuma, Justine; Cinege, Gyöngyi; Bodogai, Monica; Oláh, Boglárka; Kiers, Aurélie; Endre, Gabriella; Dupont, Laurence; Dusha, Ilona

    2014-12-01

    The symbiotic nitrogen-fixing soil bacterium Sinorhizobium meliloti carries a large number of toxin-antitoxin (TA) modules both on the chromosome and megaplasmids. One of them, the vapBC-5 module that belongs to the type II systems was characterized here. It encodes an active toxin vapC-5, and was shown to be controlled negatively by the complex of its own proteins. Different mutants of the vapBC-5 genes exhibited diverse effects on symbiotic efficiency during interaction with the host plant Medicago sativa. The absence of the entire vapBC-5 region had no influence on nodule formation and nitrogen fixation properties. The strain carrying an insertion in the antitoxin gene showed a reduced nitrogen fixation capacity resulting in a lower plant yield. In contrast, when the toxin gene was mutated, the strain developed more efficient symbiosis with the host plant. The nitrogen fixing root nodules had a delayed senescent phenotype and contained elevated level of plant-derived molecules characteristic of later steps of nodule development. The longer bacteroid viability and abundance of active nitrogen fixing zone resulted in increased production of plant material. These data indicate that modification of the toxin/antitoxin production may influence bacteroid metabolism and may have an impact on the adaptation to changing environmental conditions.

  4. Quantification of human-associated fecal indicators reveal sewage from urban watersheds as a source of pollution to Lake Michigan

    Science.gov (United States)

    Templar, Hayley A.; Dila, Deborah K.; Bootsma, Melinda J.; Corsi, Steven; McLellan, Sandra L.

    2016-01-01

    Sewage contamination of urban waterways from sewer overflows and failing infrastructure is a major environmental and public health concern. Fecal coliforms (FC) are commonly employed as fecal indicator bacteria, but do not distinguish between human and non-human sources of fecal contamination. Human Bacteroides and humanLachnospiraceae, two genetic markers for human-associated indicator bacteria, were used to identify sewage signals in two urban rivers and the estuary that drains to Lake Michigan. Grab samples were collected from the rivers throughout 2012 and 2013 and hourly samples were collected in the estuary across the hydrograph during summer 2013. Human Bacteroides and human Lachnospiraceae were highly correlated with each other in river samples (Pearson’s r = 0.86), with average concentrations at most sites elevated during wet weather. These human indicators were found during baseflow, indicating that sewage contamination is chronic in these waterways. FC are used for determining total maximum daily loads (TMDLs) in management plans; however, FC concentrations alone failed to prioritize river reaches with potential health risks. While 84% of samples with >1000 CFU/100 ml FC had sewage contamination, 52% of samples with moderate (200–1000 CFU/100 ml) and 46% of samples with low (land use, storm characteristics, and other factors that drive sewage contamination in urban waterways.

  5. Understanding how commensal obligate anaerobic bacteria regulate immune functions in the large intestine.

    Science.gov (United States)

    Maier, Eva; Anderson, Rachel C; Roy, Nicole C

    2014-12-24

    The human gastrointestinal tract is colonised by trillions of commensal bacteria, most of which are obligate anaerobes residing in the large intestine. Appropriate bacterial colonisation is generally known to be critical for human health. In particular, the development and function of the immune system depends on microbial colonisation, and a regulated cross-talk between commensal bacteria, intestinal epithelial cells and immune cells is required to maintain mucosal immune homeostasis. This homeostasis is disturbed in various inflammatory disorders, such as inflammatory bowel diseases. Several in vitro and in vivo studies indicate a role for Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Bacteroides fragilis, Akkermansia muciniphila and segmented filamentous bacteria in maintaining intestinal immune homeostasis. These obligate anaerobes are abundant in the healthy intestine but reduced in several inflammatory diseases, suggesting an association with protective effects on human health. However, knowledge of the mechanisms underlying the effects of obligate anaerobic intestinal bacteria remains limited, in part due to the difficulty of co-culturing obligate anaerobes together with oxygen-requiring human epithelial cells. By using novel dual-environment co-culture models, it will be possible to investigate the effects of the unstudied majority of intestinal microorganisms on the human epithelia. This knowledge will provide opportunities for improving human health and reducing the risk of inflammatory diseases.

  6. Rhizobium leguminosarum bv. viciae 3841 Adapts to 2,4-Dichlorophenoxyacetic Acid with "Auxin-Like" Morphological Changes, Cell Envelope Remodeling and Upregulation of Central Metabolic Pathways.

    Directory of Open Access Journals (Sweden)

    Supriya V Bhat

    Full Text Available There is a growing need to characterize the effects of environmental stressors at the molecular level on model organisms with the ever increasing number and variety of anthropogenic chemical pollutants. The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D, as one of the most widely applied pesticides in the world, is one such example. This herbicide is known to have non-targeted undesirable effects on humans, animals and soil microbes, but specific molecular targets at sublethal levels are unknown. In this study, we have used Rhizobium leguminosarum bv. viciae 3841 (Rlv as a nitrogen fixing, beneficial model soil organism to characterize the effects of 2,4-D. Using metabolomics and advanced microscopy we determined specific target pathways in the Rlv metabolic network and consequent changes to its phenotype, surface ultrastructure, and physical properties during sublethal 2,4-D exposure. Auxin and 2,4-D, its structural analogue, showed common morphological changes in vitro which were similar to bacteroids isolated from plant nodules, implying that these changes are related to bacteroid differentiation required for nitrogen fixation. Rlv showed remarkable adaptation capabilities in response to the herbicide, with changes to integral pathways of cellular metabolism and the potential to assimilate 2,4-D with consequent changes to its physical and structural properties. This study identifies biomarkers of 2,4-D in Rlv and offers valuable insights into the mode-of-action of 2,4-D in soil bacteria.

  7. Changes in human fecal microbiota due to chemotherapy analyzed by TaqMan-PCR, 454 sequencing and PCR-DGGE fingerprinting.

    Directory of Open Access Journals (Sweden)

    Jutta Zwielehner

    Full Text Available BACKGROUND: We investigated whether chemotherapy with the presence or absence of antibiotics against different kinds of cancer changed the gastrointestinal microbiota. METHODOLOGY/PRINCIPAL FINDINGS: Feces of 17 ambulant patients receiving chemotherapy with or without concomitant antibiotics were analyzed before and after the chemotherapy cycle at four time points in comparison to 17 gender-, age- and lifestyle-matched healthy controls. We targeted 16S rRNA genes of all bacteria, Bacteroides, bifidobacteria, Clostridium cluster IV and XIVa as well as C. difficile with TaqMan qPCR, denaturing gradient gel electrophoresis (DGGE fingerprinting and high-throughput sequencing. After a significant drop in the abundance of microbiota (p = 0.037 following a single treatment the microbiota recovered within a few days. The chemotherapeutical treatment marginally affected the Bacteroides while the Clostridium cluster IV and XIVa were significantly more sensitive to chemotherapy and antibiotic treatment. DGGE fingerprinting showed decreased diversity of Clostridium cluster IV and XIVa in response to chemotherapy with cluster IV diversity being particularly affected by antibiotics. The occurrence of C. difficile in three out of seventeen subjects was accompanied by a decrease in the genera Bifidobacterium, Lactobacillus, Veillonella and Faecalibacterium prausnitzii. Enterococcus faecium increased following chemotherapy. CONCLUSIONS/SIGNIFICANCE: Despite high individual variations, these results suggest that the observed changes in the human gut microbiota may favor colonization with C. difficile and Enterococcus faecium. Perturbed microbiota may be a target for specific mitigation with safe pre- and probiotics.

  8. Evaluation of fecal microorganisms of children with cleft palate before and after palatoplasty

    Directory of Open Access Journals (Sweden)

    Narciso Almeida Vieira

    2013-09-01

    Full Text Available This study isolated and quantified intestinal bacteria of children with cleft palate before and after palatoplasty. A prospective study was conducted from May 2007 to September 2008 on 18 children with cleft palate, aged one to four years, of both genders, attending a tertiary cleft center in Brazil for palatoplasty, to analyze the effect of surgical palate repair on the concentration of anaerobes Bacteroides sp, Bifidobacterium sp and microaerophiles Lactobacillus sp in feces of infants with cleft palate before and 24 hours after treatment with cefazolin for palatoplasty. There was significant reduction of Lactobacillus sp (p < 0.002, Bacteroides sp (p < 0.001 and Bifidobacterium sp (p = 0.021 after palatoplasty, revealing that surgery and utilization of cefazolin significantly influenced the fecal microbiota comparing collections before and after surgery. However, due to study limitations, it was not possible to conclude that other isolated factors, such as surgical stress, anesthetics and other medications used in palatoplasty might have a significant influence on the microbiota. Considering the important participation of the intestinal microbiota on both local and systemic metabolic and immunological activities of the host, professionals should be attentive to the possible influence of these changes in patients submitted to cleft repair.

  9. Current trends in the diagnosis and treatment of tuboovarian abscess

    Energy Technology Data Exchange (ETDEWEB)

    Landers, D.V.; Sweet, R.L.

    1985-04-15

    Tuboovarian abscess is a well-recognized complication of acute salpingitis and has been reported in as many as one third of hospital admissions for acute salpingitis. The incidence of tuboovarian abscess is expected to increase as a result of the current epidemic of sexually transmitted diseases and their sequelae. Patients with tuboovarian abscess most commonly present with lower abdominal pain and an adnexal mass(es). Fever and leukocytosis may be absent. Ultrasound, computed tomographic scans, laparoscopy, or laparotomy may be necessary to confirm the diagnosis. Tuboovarian abscess may be unilateral or bilateral regardless of intrauterine contraceptive device usage. Tuboovarian abscess is polymicrobial with a preponderance of anaerobic organisms. An initial conservative antimicrobial approach to the management of the unruptured tuboovarian abscess is appropriate if the antimicrobial agents used can penetrate abscesses, remain active within the abscess environment, and are active against the major pathogens in tuboovarian abscess, including the resistant gram-negative anaerobes such as Bacteroides fragilis and Bacteroides bivius. However, if the patient does not begin to show a response within a reasonable amount of time, about 48 to 72 hours, surgical intervention should be undertaken. Suspicion of rupture should remain an indication for immediate operation. Once operation is undertaken, a conservative approach with unilateral adnexectomy for one-side tuboovarian abscess is appropriate if future fertility or hormone production is desired.

  10. Anaerobic infections in the head and neck region.

    Science.gov (United States)

    Tabaqchali, S

    1988-01-01

    Anaerobic bacteria form the predominant flora of the oral cavity, outnumbering facultative organisms by 10-1,000: 1. The type of anaerobic bacteria and their concentration depend on the anatomical site and the degree of anaerobiosis in the different sites in the mouth. Three groups of anaerobic bacteria inhabit the oral cavity; the strict anaerobes, the moderate anaerobes, and the microaerophilic group of organisms. The majority of anaerobic bacterial infections occurring in the region of the mouth, head and neck are caused by the commensal flora. These infections include dental and periodontal disease where the predominant organisms are Bacteroides species, Veillonella, Bifidobacteria, Peptococcus, Peptostreptococcus and Propionibacterium species. More recently, Bacteroides endontalis has been isolated from a periapical abscess of endodontal origin and B. gingivalis, B. intermedius, Haemophilus actinomycetemcomitans and Wollinella species in chronic periodontal disease. Treponema species and other strict anaerobes are seen in smears of severe periodontal disease and acute necrotising gingivitis, but have not yet been isolated in pure culture. Until such time, their role in disease remains uncertain. Fusobacterium nucleatum is specially associated with severe orofacial infections which may extend into the mediastinum. Other anaerobic infections include chronic otitis media, chronic sinusitis and mastoiditis, and brain abscess. Treatment of these conditions should include the use of beta-lactamase resistant antimicrobials, such as clindamycin or one of the nitroimidazoles with penicillin.

  11. Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater

    Science.gov (United States)

    Ferguson, Andrew S.; Layton, Alice C.; Mailloux, Brian J; Culligan, Patricia J.; Williams, Daniel E.; Smartt, Abby E.; Sayler, Gary S.; Feighery, John; McKay, Larry; Knappett, Peter S.K.; Alexandrova, Ekaterina; Arbit, Talia; Emch, Michael; Escamilla, Veronica; Ahmed, Kazi Matin; Alam, Md. Jahangir; Streatfield, P. Kim; Yunus, Mohammad; van Geen, Alexander

    2012-01-01

    Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary. PMID:22705866

  12. Composition, variability, and temporal stability of the intestinal microbiota of the elderly.

    LENUS (Irish Health Repository)

    Claesson, Marcus J

    2011-03-15

    Alterations in the human intestinal microbiota are linked to conditions including inflammatory bowel disease, irritable bowel syndrome, and obesity. The microbiota also undergoes substantial changes at the extremes of life, in infants and older people, the ramifications of which are still being explored. We applied pyrosequencing of over 40,000 16S rRNA gene V4 region amplicons per subject to characterize the fecal microbiota in 161 subjects aged 65 y and older and 9 younger control subjects. The microbiota of each individual subject constituted a unique profile that was separable from all others. In 68% of the individuals, the microbiota was dominated by phylum Bacteroides, with an average proportion of 57% across all 161 baseline samples. Phylum Firmicutes had an average proportion of 40%. The proportions of some phyla and genera associated with disease or health also varied dramatically, including Proteobacteria, Actinobacteria, and Faecalibacteria. The core microbiota of elderly subjects was distinct from that previously established for younger adults, with a greater proportion of Bacteroides spp. and distinct abundance patterns of Clostridium groups. Analyses of 26 fecal microbiota datasets from 3-month follow-up samples indicated that in 85% of the subjects, the microbiota composition was more like the corresponding time-0 sample than any other dataset. We conclude that the fecal microbiota of the elderly shows temporal stability over limited time in the majority of subjects but is characterized by unusual phylum proportions and extreme variability.

  13. Carbohydrate Staple Food Modulates Gut Microbiota of Mongolians in China

    Science.gov (United States)

    Li, Jing; Hou, Qiangchuan; Zhang, Jiachao; Xu, Haiyan; Sun, Zhihong; Menghe, Bilige; Zhang, Heping

    2017-01-01

    Gut microbiota is a determining factor in human physiological functions and health. It is commonly accepted that diet has a major influence on the gut microbial community, however, the effects of diet is not fully understood. The typical Mongolian diet is characterized by high and frequent consumption of fermented dairy products and red meat, and low level of carbohydrates. In this study, the gut microbiota profile of 26 Mongolians whom consumed wheat, rice and oat as the sole carbohydrate staple food for a week each consecutively was determined. It was observed that changes in staple carbohydrate rapidly (within a week) altered gut microbial community structure and metabolic pathway of the subjects. Wheat and oat favored bifidobacteria (Bifidobacterium catenulatum, Bifodobacteriumbifidum, Bifidobacterium adolescentis); whereas rice suppressed bifidobacteria (Bifidobacterium longum, Bifidobacterium adolescentis) and wheat suppresses Lactobaciilus, Ruminococcus and Bacteroides. The study exhibited two gut microbial clustering patterns with the preference of fucosyllactose utilization linking to fucosidase genes (glycoside hydrolase family classifications: GH95 and GH29) encoded by Bifidobacterium, and xylan and arabinoxylan utilization linking to xylanase and arabinoxylanase genes encoded by Bacteroides. There was also a correlation between Lactobacillus ruminis and sialidase, as well as Butyrivibrio crossotus and xylanase/xylosidase. Meanwhile, a strong concordance was found between the gastrointestinal bacterial microbiome and the intestinal virome. Present research will contribute to understanding the impacts of the dietary carbohydrate on human gut microbiome, which will ultimately help understand relationships between dietary factor, microbial populations, and the health of global humans. PMID:28377764

  14. Bacterial pathogens induce abscess formation by CD4(+) T-cell activation via the CD28-B7-2 costimulatory pathway.

    Science.gov (United States)

    Tzianabos, A O; Chandraker, A; Kalka-Moll, W; Stingele, F; Dong, V M; Finberg, R W; Peach, R; Sayegh, M H

    2000-12-01

    Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naïve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus, Bacteroides fragilis, and a combination of Enterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28-B7-2 pathway.

  15. Assessment of Fecal Microflora Changes in Pigs Supplemented with Herbal Residue and Prebiotic.

    Directory of Open Access Journals (Sweden)

    Ashis Kumar Samanta

    Full Text Available Antibiotic usage in animals as a growth promoter is considered as public health issue due to its negative impact on consumer health and environment. The present study aimed to evaluate effectiveness of herbal residue (ginger, Zingiber officinale, dried rhizome powder and prebiotic (inulin as an alternative to antibiotics by comparing fecal microflora composition using terminal restriction fragment length polymorphism. The grower pigs were offered feed containing antibiotic (tetracycline, ginger and inulin separately and un-supplemented group served as control. The study revealed significant changes in the microbial abundance based on operational taxonomic units (OTUs among the groups. Presumptive identification of organisms was established based on the fragment length of OTUs generated with three restriction enzymes (MspI, Sau3AI and BsuRI. The abundance of OTUs representing Bacteroides intestinalis, Eubacterium oxidoreducens, Selonomonas sp., Methylobacterium sp. and Denitrobacter sp. was found significantly greater in inulin supplemented pigs. Similarly, the abundance of OTUs representing Bacteroides intestinalis, Selonomonas sp., and Phascolarcobacterium faecium was found significantly greater in ginger supplemented pigs. In contrast, the abundance of OTUs representing pathogenic microorganisms Atopostipes suicloacalis and Bartonella quintana str. Toulouse was significantly reduced in ginger and inulin supplemented pigs. The OTUs were found to be clustered under two major phylotypes; ginger-inulin and control-tetracycline. Additionally, the abundance of OTUs was similar in ginger and inulin supplemented pigs. The results suggest the potential of ginger and prebioticsto replace antibiotics in the diet of grower pig.

  16. Distribution of genetic markers of fecal pollution on a freshwater sandy shoreline in proximity to wastewater effluent.

    Science.gov (United States)

    Eichmiller, Jessica J; Hicks, Randall E; Sadowsky, Michael J

    2013-04-02

    Water, sand, and sediment from a Lake Superior harbor site continuously receiving wastewater effluent was sampled monthly for June to October 2010 and from May to September 2011. Understanding the dynamics of genetic markers of fecal bacteria in these matrices is essential to accurately characterizing health risks. Genetic markers for enterococci, total Bacteroides, and human-associated Bacteroides were measured in site-water, sand, and sediment and in final effluent by quantitative PCR. The similarity between the quantity of molecular markers in the water column and effluent indicated that the abundance of genetic markers in the water column was likely controlled by effluent inputs. Effluent turbidity was positively correlated (p ≤ 0.05) with AllBac and HF183 in final effluent and AllBac in the water column. In sand and sediment, Entero1 and AllBac were most abundant in the upper 1-3 cm depths, whereas HF183 was most abundant in the upper 1 cm of sand and at 7 cm in sediment. The AllBac and Entero1 markers were 1- and 2-orders of magnitude more abundant in sand and sediment relative to the water column per unit mass. These results indicate that sand and sediment may act as reservoirs for genetic markers of fecal pollution at some freshwater sites.

  17. Antianaerobe activity of ceftobiprole, a new broad-spectrum cephalosporin.

    Science.gov (United States)

    Ednie, Lois; Shapiro, Stuart; Appelbaum, Peter C

    2007-05-01

    Agar dilution testing of 463 anaerobes showed most Gram-positive beta-lactamase-negative strains (other than some Clostridium difficile and Peptostreptococcus anaerobius), as well as both beta-lactamase-positive and beta-lactamase-negative strains of Fusobacterium nucleatum, to have ceftobiprole MIC values of Ceftobiprole was less active against beta-lactamase-positive Gram-negative bacilli, especially the members of the Bacteroides fragilis group. Like ceftobiprole, piperacillin was active mainly against beta-lactamase-negative strains, though MIC values for piperacillin were often 1 to 2 dilutions higher than for ceftobiprole. Carbapenems had MIC values < or =4 microg/L against all except some C. difficile and 2 strains of B. fragilis. All strains were susceptible to metronidazole, and all bacteria, except C. difficile and a single Bacteroides distasonis strain, were susceptible to chloramphenicol. Clindamycin resistance was seen in most anaerobe groups, whereas high moxifloxacin MICs were found mainly among the B. fragilis and Prevotella groups, and a few C. difficile and F. nucleatum strains.

  18. A Proteomic Approach of Bradyrhizobium/Aeschynomene Root and Stem Symbioses Reveals the Importance of the fixA Locus for Symbiosis

    Directory of Open Access Journals (Sweden)

    Nathanael Delmotte

    2014-02-01

    Full Text Available Rhizobia are soil bacteria that are able to form symbiosis with plant hosts of the legume family. These associations result in the formation of organs, called nodules in which bacteria fix atmospheric nitrogen to the benefit of the plant. Most of our knowledge on the metabolism and the physiology of the bacteria during symbiosis derives from studying roots nodules of terrestrial plants. Here we used a proteomics approach to investigate the bacterial physiology of photosynthetic Bradyrhizobium sp. ORS278 during the symbiotic process with the semi aquatical plant Aeschynomene indica that forms root and stem nodules. We analyzed the proteomes of bacteria extracted from each type of nodule. First, we analyzed the bacteroid proteome at two different time points and found only minor variation between the bacterial proteomes of 2-week- and 3-week-old nodules. High conservation of the bacteroid proteome was also found when comparing stem nodules and root nodules. Among the stem nodule specific proteins were those related to the phototrophic ability of Bradyrhizobium sp. ORS278. Furthermore, we compared our data with those obtained during an extensive genetic screen previously published. The symbiotic role of four candidate genes which corresponding proteins were found massively produced in the nodules but not identified during this screening was examined. Mutant analysis suggested that in addition to the EtfAB system, the fixA locus is required for symbiotic efficiency.

  19. Detection of S-nitrosothiol and nitrosylated proteins in Arachis hypogaea functional nodule: response of the nitrogen fixing symbiont.

    Directory of Open Access Journals (Sweden)

    Debasis Maiti

    Full Text Available To detect the presence of NO, ROS and RNS in nodules of crack entry legumes, we used Arachis hypogaea functional nodule. The response of two cognate partner rhizobia was compared towards NO and GSNO using S. meliloti and Bradyrhizobium sp NC921001. ROS, NO, nitrosothiol and bacteroids were detected by fluorescence microscopy. Redox enzymes and thiol pools were detected biochemically. Nitrosothiols were found to be present but ROS and NO were absent in A. hypogaea nodule. A number of S-nitrosylated proteins were also detected. The total thiol pool and most of the redox enzymes were low in nodule cytosolic extract but these were found to be high in the partner microorganisms indicating partner rhizobia could protect the nodule environment against the nitrosothiols. Both S. meliloti and Bradyrhizobium sp NC921001 were found to contain GSNO reductase. Interestingly, there was a marked difference in growth pattern between S. meliloti and Bradyrhizobium sp in presence of sodium nitroprusside (SNP and S-nitrosoglutathione (GSNO. Bradyrhizobium sp was found to be much more tolerant to NO donor compounds than the S. meliloti. In contrast, S. meliloti showed resistance to GSNO but was sensitive to SNP. Together our data indicate that nodule environment of crack entry legumes is different than the nodules of infection mode entry in terms of NO, ROS and RNS. Based on our biochemical characterization, we propose that exchange of redox molecules and reactive chemical species is possible between the bacteroid and nodule compartment.

  20. Microgravity effects on the legume/Rhizobium symbiosis

    Science.gov (United States)

    Urban, James E.

    1997-01-01

    Symbiotic nitrogen fixation is of critical importance to world agriculture and likely will be a critical part of life support systems developed for prolonged missions in space. Bacteroid formation, an essential step in an effective Dutch White Clover/Rhizobium leguminosarum bv trifolii symbiosis, is induced by succinic acid which is produced by the plant and which is bound and incorporated by the bacterium. Aspirin mimics succinate in its role as a bacteroid inducer and measures of aspirin binding mimiced measurements of succinate binding. In normal gravity (1×g), rhizobium bacteria immediately bound relatively high levels of aspirin (or succinate) in a readily reversible manner. Within a few seconds a portion of this initially bound aspirin became irreversibly bound. In the microgravity environment aboard the NASA 930 aircraft, rhizobia did not display the initial reversible binding of succinate, but did display a similar kinetic pattern of irreversible binding, and ultimately bound 32% more succinate (Acta Astronautica 36:129-133, 1995.) In normal gravity succinate treated cells stop dividing and swell to their maximum size (twice the normal cell volume) within a time equivalent to the time required for two normal cell doublings. Swelling in microgravity was tested in FPA and BPM sample holders aboard the space shuttle (USML-1, and STS-54, 57, and 60.) The behavior of cells in the two sample holders was similar, and swelling behavior of cells in microgravity was identical to behavior in normal gravity.

  1. Morphogenesis of root nodules in white clover. II. The effect of mutation in genes nod IJ of the microsymbiont upon the nodule structure

    Directory of Open Access Journals (Sweden)

    Barbara Łotocka

    2014-01-01

    Full Text Available Morphogenesis of ineffective root nodules initiated on the roots of white clover 'Astra' by the Rhizobium leguminosarum biovar. trifolii strains ANU261 (Tn5 insertion in nod 1 gene and ANU262 (Tn5 insertion in nod J gene was investigated. Following changes were observed, as compared to the wild-type nodulation: the exaggerated, not delayed reaction of root hairs; the delay in nodulation with the number of nodules the same as in plants inoculated with a wild strain; the formation and organization of the nodule primordium not changed in comparison with the wild-type nodules; infection threads abnormally branched and diffusing with bacteria deprived of light zone and enriched with storage material; infected cells of bacteroidal tissue abnormally strongly osmiophilic and only slightly vacuolated; symbiosomes with very narrowed peribacteroidal space, subject to premature degradation; abnormal accumulation of starch in the nodule tissues; nodule development blocked at the stage of laterally situated meristem and single nodule bundle; inhibition of divisions in the meristem and vacuolation of its cells; the appearance of single cells with colonies of saprophytic rhizobia embedded in the fibrillar matrix in the old, degraded regions of the bacteroidal tissue.

  2. Intestinal microbiota and allergic diseases: A systematic review.

    Science.gov (United States)

    Melli, L C F L; do Carmo-Rodrigues, M S; Araújo-Filho, H B; Solé, D; de Morais, M B

    2016-01-01

    Evidence suggests that possible imbalances in intestinal microbiota composition may be implicated in the occurrence of allergic diseases. Although several studies published until 2006 indicated a correlation between microbiota composition and allergic symptoms, it has not been possible to distinguish protective microorganisms from those associated with increased risk of allergic diseases. Therefore, the objective of this study was to review the studies published since 2007 that address the intestinal microbiota in allergic diseases. Twenty-one studies were identified after excluding those that performed a clinical intervention before stool collection. In the early microbiota of children who later developed allergies, lower bacterial diversity was observed, with a predominance of Firmicutes; a higher count of Bacteroidaceae; a higher prevalence of the anaerobic bacteria Bacteroides fragilis, Escherichia coli, Clostridium difficile, Bifidobacterium catenulatum, Bifidobacterium bifidum, and Bifidobacterium longum; and a lower prevalence of Bifidobacterium adolescentis, B. bifidum, and Lactobacillus. In the microbiota of allergic children whose intestinal microbiota was assessed at the onset of allergic symptoms, there was a higher count of Bacteroides; a lower count of Akkermansia muciniphila, Faecalibacterium prausnitzii, and Clostridium; a higher prevalence of B. adolescentis; a lower prevalence of B. catenulatum and Staphylococcus aureus; and a lower bacterial diversity.

  3. Bacterial pericarditis in a cat

    Directory of Open Access Journals (Sweden)

    Nicole LeBlanc

    2015-09-01

    Full Text Available Case summary A 4-year-old male neutered domestic shorthair cat was presented to the Oregon State University cardiology service for suspected pericardial effusion. Cardiac tamponade was documented and pericardiocentesis yielded purulent fluid with cytologic results supportive of bacterial pericarditis. The microbial population consisted of Pasteurella multocida, Actinomyces canis, Fusobacterium and Bacteroides species. Conservative management was elected consisting of intravenous antibiotic therapy with ampicillin sodium/sulbactam sodium and metronidazole for 48 h followed by 4 weeks of oral antibiotics. Re-examination 3 months after the initial incident indicated no recurrence of effusion and the cat remained free of clinical signs 2 years after presentation. Relevance and novel information Bacterial pericarditis is a rare cause of pericardial effusion in cats. Growth of P multocida, A canis, Fusobacterium and Bacteroides species has not previously been documented in feline septic pericarditis. Conservative management with broad-spectrum antibiotics may be considered when further diagnostic imaging or exploratory surgery to search for a primary nidus of infection is not feasible or elected.

  4. Lack of glyphosate resistance gene transfer from Roundup Ready soybean to Bradyrhizobium japonicum under field and laboratory conditions.

    Science.gov (United States)

    Isaza, Laura Arango; Opelt, Katja; Wagner, Tobias; Mattes, Elke; Bieber, Evi; Hatley, Elwood O; Roth, Greg; Sanjuán, Juan; Fischer, Hans-Martin; Sandermann, Heinrich; Hartmann, Anton; Ernst, Dieter

    2011-01-01

    A field study was conducted at the Russell E. Larson Agricultural Research Center to determine the effect of transgenic glyphosate-resistant soybean in combination with herbicide (Roundup) application on its endosymbiont Bradyrhizobium japonicum. DNA of bacteroids from isolated nodules was analysed for the presence of the transgenic 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS) DNA sequence using polymerase chain reaction (PCR). To further assess the likelihood that the EPSPS gene may be transferred from the Roundup Ready (RR) soybean to B. japonicum, we have examined the natural transformation efficiency of B. japonicum strain 110spc4. Analyses of nodules showed the presence of the transgenic EPSPS DNA sequence. In bacteroids that were isolated from nodules of transgenic soybean plants and then cultivated in the presence of glyphosate this sequence could not be detected. This indicates that no stable horizontal gene transfer (HGT) of the EPSPS gene had occurred under field conditions. Under laboratory conditions, no natural transformation was detected in B. japonicum strain 110spc4 in the presence of various amounts of recombinant plasmid DNA. Our results indicate that no natural competence state exists in B. japonicum 110spc4. Results from field and laboratory studies indicate the lack of functional transfer of the CP4-EPSPS gene from glyphosate-tolerant soybean treated with glyphosate to root-associated B. japonicum.

  5. Phylogeny of culturable estuarine bacteria catabolizing riverine organic matter in the northern Baltic Sea.

    Science.gov (United States)

    Kisand, Veljo; Cuadros, Rocio; Wikner, Johan

    2002-01-01

    The objective of our study was to isolate and determine the phylogenetic affiliation of culturable estuarine bacteria capable of catabolizing riverine dissolved organic matter (RDOM) under laboratory conditions. Additions of RDOM consistently promoted the growth of estuarine bacteria in carbon-limited dilution cultures, with seasonal variation in growth rates and yields. At least 42 different taxa were culturable on solid agar media and, according to quantitative DNA-DNA hybridizations, constituted 32 to 89% of the total bacterial number in the enriched treatments. Five species in the Cytophaga-Flexibacter-Bacteroides group and one in the gamma-proteobacteria phylogenetic group (Marinomonas sp.) were numerically dominant during the stationary phase of the RDOM-enriched dilution cultures but not in the control cultures. Four of the isolates in Cytophaga-Flexibacter-Bacteroides group were putatively affiliated with the genus FLAVOBACTERIUM: All dominating isolates were determined to be new species based on comparison to the current databases. The same group of species dominated independently of the season investigated, suggesting a low diversity of bacteria catabolizing RDOM in the estuary. It also suggested a broad tolerance of the dominating species to seasonal variation in hydrography, chemistry, and competition with other species. Taken together, our results suggest that a limited group of bacteria, mainly in the Flavobacterium genus, played an important role in introducing new energy and carbon to the marine system in the northern Baltic Sea.

  6. Establishment of intestinal microbiota during early life: a longitudinal, explorative study of a large cohort of Danish infants.

    Science.gov (United States)

    Bergström, Anders; Skov, Thomas Hjort; Bahl, Martin Iain; Roager, Henrik Munch; Christensen, Line Brinch; Ejlerskov, Katrine Tschentscher; Mølgaard, Christian; Michaelsen, Kim F; Licht, Tine Rask

    2014-05-01

    Fecal samples were obtained from a cohort of 330 healthy Danish infants at 9, 18, and 36 months after birth, enabling characterization of interbacterial relationships by use of quantitative PCR targeting 31 selected bacterial 16S rRNA gene targets representing different phylogenetic levels. Nutritional parameters and measures of growth and body composition were determined and investigated in relation to the observed development in microbiota composition. We found that significant changes in the gut microbiota occurred, particularly from age 9 to 18 months, when cessation of breastfeeding and introduction of a complementary feeding induce replacement of a microbiota characterized by lactobacilli, bifidobacteria, and Enterobacteriaceae with a microbiota dominated by Clostridium spp. and Bacteroides spp. Classification of samples by a proxy enterotype based on the relative levels of Bacteroides spp. and Prevotella spp. showed that enterotype establishment occurs between 9 and 36 months. Thirty percent of the individuals shifted enterotype between 18 and 36 months. The composition of the microbiota was most pronouncedly influenced by the time of cessation of breastfeeding. From 9 to 18 months, a positive correlation was observed between the increase in body mass index and the increase of the short-chain-fatty-acid-producing clostridia, the Clostridum leptum group, and Eubacterium hallii. Considering previously established positive associations between rapid infant weight gain, early breastfeeding discontinuation, and later-life obesity, the corresponding microbial findings seen here warrant attention.

  7. Quantification of human-associated fecal indicators reveal sewage from urban watersheds as a source of pollution to Lake Michigan.

    Science.gov (United States)

    Templar, Hayley A; Dila, Deborah K; Bootsma, Melinda J; Corsi, Steven R; McLellan, Sandra L

    2016-09-01

    Sewage contamination of urban waterways from sewer overflows and failing infrastructure is a major environmental and public health concern. Fecal coliforms (FC) are commonly employed as fecal indicator bacteria, but do not distinguish between human and non-human sources of fecal contamination. Human Bacteroides and human Lachnospiraceae, two genetic markers for human-associated indicator bacteria, were used to identify sewage signals in two urban rivers and the estuary that drains to Lake Michigan. Grab samples were collected from the rivers throughout 2012 and 2013 and hourly samples were collected in the estuary across the hydrograph during summer 2013. Human Bacteroides and human Lachnospiraceae were highly correlated with each other in river samples (Pearson's r = 0.86), with average concentrations at most sites elevated during wet weather. These human indicators were found during baseflow, indicating that sewage contamination is chronic in these waterways. FC are used for determining total maximum daily loads (TMDLs) in management plans; however, FC concentrations alone failed to prioritize river reaches with potential health risks. While 84% of samples with >1000 CFU/100 ml FC had sewage contamination, 52% of samples with moderate (200-1000 CFU/100 ml) and 46% of samples with low (urban areas have unrecognized sewage inputs that may not be adequately prioritized for remediation by the TMDL process. Further analysis using these approaches could determine relationships between land use, storm characteristics, and other factors that drive sewage contamination in urban waterways.

  8. [Role of infectious agents in the emergence of malignant tumors].

    Science.gov (United States)

    Kutikhin, A G; Yuzhalin, A E; Brusina, E B; Briko, N I

    2012-01-01

    According to the data of the International Agency for Research on Cancer (IARC), at least 6 virus species (HPV, EBV, HHV-8/KSHV, HTLV-1, HBV, HCV), 4 helminthes species (Schistosoma haematobium and japonicum, Opisthorchis viverrini, Clonorchis sinensis) and I bacterium species (Helicobacter pylori) have been proved to be capable of causing the development of cancer. The analysis of the data available shows that Merkel cell polyomavirus (MCV), herpes simplex virus (HSV), John Cunningham polyomavirus (JCV), monkey virus 40 (SV40), cytomegalovirus (CMV), xenotropic murine leukemia virus (XMRV), Helicobacter bilis and hepaticus, Campylobacter jejuni, Fusobacterium varium, enteropathogenic Escherichia coli, enterotoxigenic Bacteroides fragilis, Bacteroides vulgatus, Prevotella spp., Streptococcus bovis and anginosus, Treponema denticola, Salmonella typhi, paratyphi and typhimurium, Borrelia burgdorferi, Bartonella spp., Mycobacterium tuberculosis, Chlamydia pneumoniae, trachomatis and psittaci, Neisseria gonorrhoeae, Propionibacterium acnes, Tropheryma whippelii, Schistosoma mansoni, Opistorchis felineus, Strongyloides stercoralis, Taenia solium, Candida spp., Paracoccidioides brasiliensis, Histoplasma capsulatum and Trichomonas vaginalis can also be potential etiological agents of cancer. Apparently, detection of new associations between infectious agents and risk of the development of cancer will facilitate progress in elaboration of prophylaxis measures, early diagnostic methods and, probably, methods of treatment of malignant tumors.

  9. Microbiota saprófita associada à doença periodontal em cães Oral flora associated with periodontal disease in dogs

    Directory of Open Access Journals (Sweden)

    L.M. Domingues

    1999-08-01

    Full Text Available Realizou-se um estudo sobre a microbiota saprófita associada à doença periodontal espontânea em cães com o objetivo de identificar as bactérias anaeróbias predominantes nas lesões. Com auxílio de cureta odontológica, amostras colhidas diretamente do espaço subgengival foram semeadas em meio CDC (Central for Disease Control para anaeróbios e incubadas, em anaerobiose, a 37°C, por sete dias. A caracterização das colônias foi realizada por meio da morfologia e do teste bioquímico (Sistema API 20AÒ. Identificaram-se os seguintes gêneros: Prevotella spp., Bacteroides spp., Propionibacterium spp., Gemella spp., Actinomyces spp., Eubacterium spp. e Porphyromonas spp.Anaerobic bacteria associated with spontaneous periodontal disorders were studied. The samples were directly colected from the subgingival space with a odontologic curet, and they were plated in Central for Disease Control culture medium for anaerobic bacteria and incubated in anaerobic conditions at 37°C for seven days. The characterization of the colonies were done by the morphologic study and biochemical tests (API 20A. Prevotella spp., Bacteroides spp., Propionibacterium spp., Actinomyces spp., Eubacterium spp., Porphyromonas spp. and Gemella spp. were identified in the samples.

  10. Growth Rate of and Gene Expression in Bradyrhizobium diazoefficiens USDA110 due to a Mutation in blr7984, a TetR Family Transcriptional Regulator Gene.

    Science.gov (United States)

    Ohkama-Ohtsu, Naoko; Honma, Haruna; Nakagome, Mariko; Nagata, Maki; Yamaya-Ito, Hiroko; Sano, Yoshiaki; Hiraoka, Norina; Ikemi, Takaaki; Suzuki, Akihiro; Okazaki, Shin; Minamisawa, Kiwamu; Yokoyama, Tadashi

    2016-09-29

    Previous transcriptome analyses have suggested that a gene cluster including a transcriptional regulator (blr7984) of the tetracycline repressor family was markedly down-regulated in symbiosis. Since blr7984 is annotated to be the transcriptional repressor, we hypothesized that it is involved in the repression of genes in the genomic cluster including blr7984 in symbiotic bacteroids. In order to examine the function and involvement of the blr7984 gene in differentiation into bacteroids, we compared the free-living growth/symbiotic phenotype and gene expression between a blr7984-knockout mutant and the wild-type strain of Bradyrhizobium diazoefficiens USDA110. The mutant transiently increased the cell growth rate under free-living conditions and nodule numbers over those with the wild-type strain USDA110. The expression of three genes adjacent to the disrupted blr7984 gene was strongly up-regulated in the mutant in free-living and symbiotic cells. The mutant also induced the expression of genes for glutathione S-transferase, cytochrome c oxidases, ABC transporters, PTS sugar transport systems, and flagella synthesis under free-living conditions. bll7983 encoding glutathione S-transferase was up-regulated the most by the blr7984 disruption. Since redox regulation by glutathione is known to be involved in cell division in prokaryotes and eukaryotes, the strong expression of glutathione S-transferase encoded by the bll7983 gene may have caused redox changes in mutant cells, which resulted in higher rates of cell division.

  11. Gut Microbiota Linked to Sexual Preference and HIV Infection

    Directory of Open Access Journals (Sweden)

    Marc Noguera-Julian

    2016-03-01

    Full Text Available The precise effects of HIV-1 on the gut microbiome are unclear. Initial cross-sectional studies provided contradictory associations between microbial richness and HIV serostatus and suggested shifts from Bacteroides to Prevotella predominance following HIV-1 infection, which have not been found in animal models or in studies matched for HIV-1 transmission groups. In two independent cohorts of HIV-1-infected subjects and HIV-1-negative controls in Barcelona (n = 156 and Stockholm (n = 84, men who have sex with men (MSM predominantly belonged to the Prevotella-rich enterotype whereas most non-MSM subjects were enriched in Bacteroides, independently of HIV-1 status, and with only a limited contribution of diet effects. Moreover, MSM had a significantly richer and more diverse fecal microbiota than non-MSM individuals. After stratifying for sexual orientation, there was no solid evidence of an HIV-specific dysbiosis. However, HIV-1 infection remained consistently associated with reduced bacterial richness, the lowest bacterial richness being observed in subjects with a virological-immune discordant response to antiretroviral therapy. Our findings indicate that HIV gut microbiome studies must control for HIV risk factors and suggest interventions on gut bacterial richness as possible novel avenues to improve HIV-1-associated immune dysfunction.

  12. Gut Microbiota Linked to Sexual Preference and HIV Infection

    Science.gov (United States)

    Noguera-Julian, Marc; Rocafort, Muntsa; Guillén, Yolanda; Rivera, Javier; Casadellà, Maria; Nowak, Piotr; Hildebrand, Falk; Zeller, Georg; Parera, Mariona; Bellido, Rocío; Rodríguez, Cristina; Carrillo, Jorge; Mothe, Beatriz; Coll, Josep; Bravo, Isabel; Estany, Carla; Herrero, Cristina; Saz, Jorge; Sirera, Guillem; Torrela, Ariadna; Navarro, Jordi; Crespo, Manel; Brander, Christian; Negredo, Eugènia; Blanco, Julià; Guarner, Francisco; Calle, Maria Luz; Bork, Peer; Sönnerborg, Anders; Clotet, Bonaventura; Paredes, Roger

    2016-01-01

    The precise effects of HIV-1 on the gut microbiome are unclear. Initial cross-sectional studies provided contradictory associations between microbial richness and HIV serostatus and suggested shifts from Bacteroides to Prevotella predominance following HIV-1 infection, which have not been found in animal models or in studies matched for HIV-1 transmission groups. In two independent cohorts of HIV-1-infected subjects and HIV-1-negative controls in Barcelona (n = 156) and Stockholm (n = 84), men who have sex with men (MSM) predominantly belonged to the Prevotella-rich enterotype whereas most non-MSM subjects were enriched in Bacteroides, independently of HIV-1 status, and with only a limited contribution of diet effects. Moreover, MSM had a significantly richer and more diverse fecal microbiota than non-MSM individuals. After stratifying for sexual orientation, there was no solid evidence of an HIV-specific dysbiosis. However, HIV-1 infection remained consistently associated with reduced bacterial richness, the lowest bacterial richness being observed in subjects with a virological-immune discordant response to antiretroviral therapy. Our findings indicate that HIV gut microbiome studies must control for HIV risk factors and suggest interventions on gut bacterial richness as possible novel avenues to improve HIV-1-associated immune dysfunction. PMID:27077120

  13. Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene.

    Science.gov (United States)

    Verstraelen, Hans; Vilchez-Vargas, Ramiro; Desimpel, Fabian; Jauregui, Ruy; Vankeirsbilck, Nele; Weyers, Steven; Verhelst, Rita; De Sutter, Petra; Pieper, Dietmar H; Van De Wiele, Tom

    2016-01-01

    Background. It is widely assumed that the uterine cavity in non-pregnant women is physiologically sterile, also as a premise to the long-held view that human infants develop in a sterile uterine environment, though likely reflecting under-appraisal of the extent of the human bacterial metacommunity. In an exploratory study, we aimed to investigate the putative presence of a uterine microbiome in a selected series of non-pregnant women through deep sequencing of the V1-2 hypervariable region of the 16S ribosomal RNA (rRNA) gene. Methods. Nineteen women with various reproductive conditions, including subfertility, scheduled for hysteroscopy and not showing uterine anomalies were recruited. Subjects were highly diverse with regard to demographic and medical history and included nulliparous and parous women. Endometrial tissue and mucus harvesting was performed by use of a transcervical device designed to obtain endometrial biopsy, while avoiding cervicovaginal contamination. Bacteria were targeted by use of a barcoded Illumina MiSeq paired-end sequencing method targeting the 16S rRNA gene V1-2 region, yielding an average of 41,194 reads per sample after quality filtering. Taxonomic annotation was pursued by comparison with sequences available through the Ribosomal Database Project and the NCBI database. Results. Out of 183 unique 16S rRNA gene amplicon sequences, 15 phylotypes were present in all samples. In some 90% of the women included, community architecture was fairly similar inasmuch B. xylanisolvens, B. thetaiotaomicron, B. fragilis and an undetermined Pelomonas taxon constituted over one third of the endometrial bacterial community. On the singular phylotype level, six women showed predominance of L. crispatus or L. iners in the presence of the Bacteroides core. Two endometrial communities were highly dissimilar, largely lacking the Bacteroides core, one dominated by L. crispatus and another consisting of a highly diverse community, including Prevotella spp

  14. Influence of Bifidobacterium longum BB536 intake on faecal microbiota in individuals with Japanese cedar pollinosis during the pollen season.

    Science.gov (United States)

    Odamaki, Toshitaka; Xiao, Jin-Zhong; Iwabuchi, Noriyuki; Sakamoto, Mitsuo; Takahashi, Noritoshi; Kondo, Shizuki; Miyaji, Kazuhiro; Iwatsuki, Keiji; Togashi, Hideo; Enomoto, Tadao; Benno, Yoshimi

    2007-10-01

    It has been reported that intake of yogurt or powder supplemented with the Bifidobacterium longum BB536 probiotic strain alleviated subjective symptoms and affected blood markers of allergy in individuals with Japanese cedar pollinosis (JCPsis) during the pollen seasons of 2004 and 2005, based on randomized, double-blind, placebo-controlled trials. Furthermore, the 2004 study found that intestinal bacteria such as the Bacteroides fragilis group significantly fluctuated during the pollen season in JCPsis individuals and intake of BB536 yogurt tended to suppress these fluctuations. The present study investigated faecal microbiota to examine whether any changes occurred during the pollen season and whether any influence was exerted by intake of BB536 powder in the 2005 pollen season, which happened to be a heavy season, to confirm the 2004 findings and to evaluate the relationship of microbiota with symptom development. In a randomized, double-blind, placebo-controlled trial, 44 JCPsis subjects received BB536 or a placebo for 13 weeks during the pollen season. Another 14 Japanese cedar pollen (JCP)-specific IgE negative healthy subjects received placebo for the same period. Faecal samples were collected before (week 0), during (weeks 4, 8 and 13) and after (week 17) intervention, and out of JCP season (week 28). Faecal microbiota were analysed using terminal-RFLP (T-RFLP) and real-time PCR methods. Principal component analysis based on T-RFLP indicated distinct patterns of microbiota between healthy subjects and JCPsis subjects in the placebo group, but an intermediate pattern in the BB536 group at week 13, the last stage of the pollen season. The coordinate of principal component 1 at week 13 correlated with composite scores of JCPsis symptoms recorded during the pollen season. Faecalibacterium prausnitzii and the Bacteroides fragilis group were identified as the main contributors to microbiotal fluctuations. Real-time PCR indicated that BB536 intake suppressed

  15. Tissue-Associated Bacterial Alterations in Rectal Carcinoma Patients Revealed by 16S rRNA Community Profiling

    Science.gov (United States)

    Thomas, Andrew M.; Jesus, Eliane C.; Lopes, Ademar; Aguiar, Samuel; Begnami, Maria D.; Rocha, Rafael M.; Carpinetti, Paola Avelar; Camargo, Anamaria A.; Hoffmann, Christian; Freitas, Helano C.; Silva, Israel T.; Nunes, Diana N.; Setubal, João C.; Dias-Neto, Emmanuel

    2016-01-01

    Sporadic and inflammatory forms of colorectal cancer (CRC) account for more than 80% of cases. Recent publications have shown mechanistic evidence for the involvement of gut bacteria in the development of both CRC-forms. Whereas, colon and rectal cancer have been routinely studied together as CRC, increasing evidence show these to be distinct diseases. Also, the common use of fecal samples to study microbial communities may reflect disease state but possibly not the tumor microenvironment. We performed this study to evaluate differences in bacterial communities found in tissue samples of 18 rectal-cancer subjects when compared to 18 non-cancer controls. Samples were collected during exploratory colonoscopy (non-cancer group) or during surgery for tumor excision (rectal-cancer group). High throughput 16S rRNA amplicon sequencing of the V4–V5 region was conducted on the Ion PGM platform, reads were filtered using Qiime and clustered using UPARSE. We observed significant increases in species richness and diversity in rectal cancer samples, evidenced by the total number of OTUs and the Shannon and Simpson indexes. Enterotyping analysis divided our cohort into two groups, with the majority of rectal cancer samples clustering into one enterotype, characterized by a greater abundance of Bacteroides and Dorea. At the phylum level, rectal-cancer samples had increased abundance of candidate phylum OD1 (also known as Parcubacteria) whilst non-cancer samples had increased abundance of Planctomycetes. At the genera level, rectal-cancer samples had higher abundances of Bacteroides, Phascolarctobacterium, Parabacteroides, Desulfovibrio, and Odoribacter whereas non-cancer samples had higher abundances of Pseudomonas, Escherichia, Acinetobacter, Lactobacillus, and Bacillus. Two Bacteroides fragilis OTUs were more abundant among rectal-cancer patients seen through 16S rRNA amplicon sequencing, whose presence was confirmed by immunohistochemistry and enrichment verified by digital

  16. Acetyl Coenzyme A Acetyltransferase of Rhizobium sp. (Cicer) Strain CC 1192.

    Science.gov (United States)

    Kim, S A; Copeland, L

    1997-09-01

    To investigate why Rhizobium sp. (Cicer) strain CC 1192 cells accumulate poly-R-3-hydroxybutyrate in the free-living state but not as bacteroids in nodules on chickpea (Cicer arietinum L.) plants, we have examined the kinetic properties of acetyl coenzyme A (acetyl-CoA) acetyltransferase (also known as acetoacetyl-CoA thiolase and 3-ketothiolase [EC 2.3.1.9]) from both types of cells. The enzyme had a native molecular mass of 180 (plusmn) 4 kDa, and the subunit molecular mass was 44 (plusmn) 1 kDa. The seven amino acids from the N terminus were Lys-Ala-Ser-Ile-Val-Ile-Ala. Thiolysis and condensation activity of the enzyme from free-living CC 1192 cells were optimal at pHs 7.8 and 8.1, respectively. The relationship between substrate concentrations and initial velocity for the thiolysis reaction were hyperbolic and gave K(infm) values for acetoacetyl-CoA and CoA of 42 and 56 (mu)M, respectively. The maximum velocity in the condensation direction was approximately 10% of that of the thiolysis reaction. With highly purified preparations of the enzyme, a value of approximately 1 mM was determined for the apparent K(infm) for acetyl-CoA. However, with partially purified enzyme preparations or when N-ethylmaleimide was included in reaction mixtures the apparent K(infm) for acetyl-CoA was close to 0.3 mM. In the condensation direction, CoA was a potent linear competitive inhibitor with an inhibition constant of 11 (mu)M. The much higher affinity of the enzyme for the product CoA than the substrate acetyl-CoA could have significance in view of metabolic differences between bacteroid and free-living cells of CC 1192. We propose that in free-living CC 1192 cells, the acetyl-CoA/CoA ratio reaches a value that allows condensation activity of acetyl-CoA acetyltransferase, but that in CC 1192 bacteroids, the ratio is poised so that the formation of acetoacetyl-CoA is not favored.

  17. Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene

    Directory of Open Access Journals (Sweden)

    Hans Verstraelen

    2016-01-01

    Full Text Available Background. It is widely assumed that the uterine cavity in non-pregnant women is physiologically sterile, also as a premise to the long-held view that human infants develop in a sterile uterine environment, though likely reflecting under-appraisal of the extent of the human bacterial metacommunity. In an exploratory study, we aimed to investigate the putative presence of a uterine microbiome in a selected series of non-pregnant women through deep sequencing of the V1-2 hypervariable region of the 16S ribosomal RNA (rRNA gene.Methods. Nineteen women with various reproductive conditions, including subfertility, scheduled for hysteroscopy and not showing uterine anomalies were recruited. Subjects were highly diverse with regard to demographic and medical history and included nulliparous and parous women. Endometrial tissue and mucus harvesting was performed by use of a transcervical device designed to obtain endometrial biopsy, while avoiding cervicovaginal contamination. Bacteria were targeted by use of a barcoded Illumina MiSeq paired-end sequencing method targeting the 16S rRNA gene V1-2 region, yielding an average of 41,194 reads per sample after quality filtering. Taxonomic annotation was pursued by comparison with sequences available through the Ribosomal Database Project and the NCBI database.Results. Out of 183 unique 16S rRNA gene amplicon sequences, 15 phylotypes were present in all samples. In some 90% of the women included, community architecture was fairly similar inasmuch B. xylanisolvens, B. thetaiotaomicron, B. fragilis and an undetermined Pelomonas taxon constituted over one third of the endometrial bacterial community. On the singular phylotype level, six women showed predominance of L. crispatus or L. iners in the presence of the Bacteroides core. Two endometrial communities were highly dissimilar, largely lacking the Bacteroides core, one dominated by L. crispatus and another consisting of a highly diverse community, including

  18. Obesity Alters the Microbial Community Profile in Korean Adolescents.

    Directory of Open Access Journals (Sweden)

    Hae-Jin Hu

    Full Text Available Obesity is an increasing public health concern worldwide. According to the latest Organization for Economic Co-operation and Development (OECD report (2014, the incidence of child obesity in Korea has exceeded the OECD average. To better understand and control this condition, the present study examined the composition of the gut microbial community in normal and obese adolescents. Fecal samples were collected from 67 obese (body mass index [BMI] ≥ 30 kg/m2, or ≥ 99th BMI percentile and 67 normal (BMI < 25 kg/m2 or < 85th BMI percentile Korean adolescents aged 13-16 years and subjected to 16S rRNA gene sequencing. Analysis of bacterial composition according to taxonomic rank (genus, family, and phylum revealed marked differences in the Bacteroides and Prevotella populations in normal and obese samples (p < 0.005 at the genus and family levels; however, there was no difference in the Firmicutes-to-Bacteroidetes (F/B ratio between normal and obese adolescents samples at the phylum level (F/B normal = 0.50 ± 0.53; F/B obese = 0.56 ± 0.86; p = 0.384. Statistical analysis revealed a significant association between the compositions of several bacterial taxa and child obesity. Among these, Bacteroides and Prevotella showed the most significant association with BMI (p < 0.0001 and 0.0001, respectively. We also found that the composition of Bacteroides was negatively associated with triglycerides (TG, total cholesterol, and high-sensitive C-reactive protein (hs-crp (p = 0.0049, 0.0023, and 0.0038, respectively levels, whereas that of Prevotella was positively associated with TG and hs-crp levels (p = 0.0394 and 0.0150, respectively. We then applied the association rule mining algorithm to generate "rules" to identify the association between the populations of multiple bacterial taxa and obesity; these rules were able to discriminate obese from normal states. Therefore, the present study describes a systemic approach to identify the association

  19. Glutamine synthetase I-deficiency in Mesorhizobium loti differentially affects nodule development and activity in Lotus japonicus.

    Science.gov (United States)

    Chungopast, Sirinapa; Thapanapongworakul, Pilunthana; Matsuura, Hiroyuki; Van Dao, Tan; Asahi, Toshimasa; Tada, Kuninao; Tajima, Shigeyuki; Nomura, Mika

    2014-03-01

    In this study, we focused on the effect of glutamine synthetase (GSI) activity in Mesorhizobium loti on the symbiosis between the host plant, Lotus japonicus, and the bacteroids. We used a signature-tagged mutant of M. loti (STM30) with a transposon inserted into the GSI (mll0343) gene. The L. japonicus plants inoculated with STM30 had significantly more nodules, and the occurrence of senesced nodules was much higher than in plants inoculated with the wild-type. The acetylene reduction activity (ARA) per nodule inoculated with STM30 was lowered compared to the control. Also, the concentration of chlorophyll, glutamine, and asparagine in leaves of STM30-infected plants was found to be reduced. Taken together, these data demonstrate that a GSI deficiency in M. loti differentially affects legume-rhizobia symbiosis by modifying nodule development and metabolic processes.

  20. Antimicrobial Activity of Diterpenes from Viguiera arenaria against Endodontic Bacteria

    Directory of Open Access Journals (Sweden)

    Carlos H. G. Martins

    2011-01-01

    Full Text Available Six pimarane-type diterpenes isolated from Viguiera arenaria Baker and two semi-synthetic derivatives were evaluated in vitro against a panel of representative microorganisms responsible for dental root canal infections. The microdilution method was used for the determination of the minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC against Porphyromonas gingivalis, Prevotella nigrescens, Prevotella intermedia, Prevotella buccae, Fusobacterium nucleatum, Bacteroides fragilis, Actinomyces naeslundii, Actinomyces viscosus, Peptostreptococcus micros, Enterococcus faecalis and Aggregatibacter actinomycetemcomitans. The compounds ent-pimara-8(14,15-dien-19-oic acid, its sodium salt and ent-8(14,15-pimaradien-3β-ol were the most active, displaying MIC values ranging from 1 to 10 μg mL-1. The results also allow us to conclude that minor structural differences among these diterpenes significantly influence their antimicrobial activity, bringing new perspectives to the discovery of new chemicals for use as a complement to instrumental endodontic procedures.

  1. [Characterization of the microflora of the small intestine (author's transl)].

    Science.gov (United States)

    Bernhardt, H; Knoke, M

    1980-03-01

    Normal and abnormal microflora of the upper small intestine was studied in 356 patients. Low counts are characteristic of normal microbial colonization (eubiosis), changes in quality and/or quantity are pathological (dysbiosis). The latter status is described as overgrowth syndrome. We found some types of dysbiosis. Prevalent was type Dys1 with the highest counts and the greatest variety of bacteria and yeasts. In contrast to this, type Dys2 showed higher germ counts of only one genus like coliforms (Dys2 Coli), streptococci (Dys2 Str.), lactobacilli (Dys2 L.) or yeasts (Dys2 Y.). In dysbiosis, we frequently saw bifidobacterium and bacteroides. Simultaneous sampling from stomach, duodenum, and jejunum indicated different modes of colonization of these parts (oral or fecal type).

  2. Isolation and identification of quercetin degrading bacteria from human fecal microbes.

    Directory of Open Access Journals (Sweden)

    Zhichao Zhang

    Full Text Available Quercetin has a wide range of biological properties. The gut microflora can often modulate its biological activity and their potential health effects. There still is a lack of information about gut bacteria involving in this process. The strains of gut microbes from human feces that can transform quercetin were isolated and identified by in vitro fermentation. The results showed that Escherichia coli, Stretococcus lutetiensis, Lactobacillus acidophilus, Weissella confusa, Enterococcus gilvus, Clostridium perfringens and Bacteroides fragilis have the various ability of degrading quercetin. Among them, C. perfringens and B. fragilis were discovered to have the strongest ability of degrading quercetin. Additionally, quercetin can't inhibit the growth of C. perfringens. In conclusion, many species of gut microbiota can degrade quercetin, but their ability are different.

  3. Utility of Microbial Source-Tracking Markers for Assessing Fecal Contamination in the Portage River Watershed, Northwestern Ohio, 2008

    Science.gov (United States)

    Kephart, Christopher M.; Bushon, Rebecca N.

    2010-01-01

    An influx of concentrated animal feeding operations in northwest Ohio has prompted local agencies to examine the effects of these industrial farms on water quality in the upper Portage River watershed. The utility of microbial source-tracking (MST) tools as a means of characterizing sources of fecal contamination in the watershed was evaluated. From 2007 to 2008, scientists with the U.S. Geological Survey, Bowling Green State University, and the Wood County Health Department collected and analyzed 17 environmental samples and 13 fecal source samples for Bacteroides-based host-associated DNA markers. At many of the environmental sites tested, MST marker results corroborated the presumptive fecal contamination sources. Results from this demonstration study support the utility of using MST with host-specific molecular markers to characterize the sources of fecal contamination in the Portage River watershed.

  4. In vivo effects on the intestinal microflora of Physalis alkekengi var. francheti extracts.

    Science.gov (United States)

    Li, Xinli; Zhang, Cuili; Li, Weiling; Wu, Dachang; Liu, Jianjun; Tang, Li; Xin, Yi

    2013-06-01

    This study aimed to investigate the effects on the intestinal microflora balance of Physalis alkekengi var. francheti extracts (PE) using in vivo mouse model. Luteolin-7-O-β-glycoside, Physalin J, Physalin D, and Physalin P were isolated from PE extracts and identified. Bacteroides, Lactobacillus, Helicobacter, Prevotella, Odoribacter and Oribacterium were detected as dominant organisms in the intestinal tract of mice by denaturing gradient gel electrophoresis (DGGE) analysis. The quality and quantity of Lactobacillus genus increased significantly with increasing concentration of PE. This study shows that the intestinal microflora balance could be improved by PE, and thus, it has the significant potential to be used as a natural agent for restoring the intestinal microflora balance.

  5. Detection of gram-negative bacteremia by limulus amebocyte lysate assay: evaluation in a rat model of peritonitis.

    Science.gov (United States)

    du Moulin, G C; Lynch, S E; Hedley-Whyte, J; Broitman, S A

    1985-01-01

    A spectrophotometric Limulus amebocyte lysate assay using lysis filtration and centrifugation has been developed for the detection of gram-negative bacteria in blood. The assay is directed at detection of endotoxin in viable and nonviable bacteria present in the blood-stream and not detection of free endotoxin in plasma. The assay was evaluated in a model of peritonitis in which rats were challenged with an inoculum consisting of sterilized human feces, barium sulfate, and one of eight species of bacteria. This assay was able to detect gram-negative bacteremia due to Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Proteus mirabilis, and Klebsiella pneumoniae in the rat model when compared with sham-inoculated uninfected rats. The assay failed to detect bacteremia due to Bacteroides fragilis or Staphylococcus aureus, nor was there a significant rise in absorbance when a pellet containing sterilized feces was implanted in the rat.

  6. Molecular genetic diversity of bacteria in the bottom section of arctic sea ice from the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    LI Huirong; YU Yong; CHEN Bo; ZENG Yinxin; REN Daming

    2005-01-01

    PCR-DGGE approach was used to analyze bacterial diversity in the bottom section of seven arctic sea ice samples colleted from the Canada Basin. Thirty-two 16S rDNA sequences were obtained from prominent DGGE bands. The closest relatives of these sequences are found to be those of cultivated or uncultured bacteria from antarctic or arctic sea ice. Phylogenetic analysis clustered these sequences or phylotypes within α- proteobacteria, γ-proteobacteria and CFB (cytophaga-flexibacter-bacteroides) group. Sequences belonging to γ-proteobacteria were dominant and members of the CFB group were highly abundant. It was suggested that the CFB group was the representative of the bottom section of sea ice samples.

  7. Dietary Fiber-Induced Improvement in Glucose Metabolism Is Associated with Increased Abundance of Prevotella

    DEFF Research Database (Denmark)

    Kovatcheva-Datchary, Petia; Nilsson, Anne; Akrami, Rozita

    2015-01-01

    The gut microbiota plays an important role in human health by interacting with host diet, but there is substantial inter-individual variation in the response to diet. Here we compared the gut microbiota composition of healthy subjects who exhibited improved glucose metabolism following 3-day...... consumption of barley kernel-based bread (BKB) with those who responded least to this dietary intervention. The Prevotella/Bacteroides ratio was higher in responders than non-responders after BKB. Metagenomic analysis showed that the gut microbiota of responders was enriched in Prevotella copri and had...... increased potential to ferment complex polysaccharides after BKB. Finally, germ-free mice transplanted with microbiota from responder human donors exhibited improved glucose metabolism and increased abundance of Prevotella and liver glycogen content compared with germ-free mice that received non...

  8. Evaluation of postmortem bacterial migration using culturing and real-time quantitative PCR.

    Science.gov (United States)

    Tuomisto, Sari; Karhunen, Pekka J; Vuento, Risto; Aittoniemi, Janne; Pessi, Tanja

    2013-07-01

    Postmortem bacteriology can be a valuable tool for evaluating deaths due to bacterial infection or for researching the involvement of bacteria in various diseases. In this study, time-dependent postmortem bacterial migration into liver, mesenteric lymph node, pericardial fluid, portal, and peripheral vein was analyzed in 33 autopsy cases by bacterial culturing and real-time quantitative polymerase chain reaction (RT-qPCR). None suffered or died from bacterial infection. According to culturing, pericardial fluid and liver were the most sterile samples up to 5 days postmortem. In these samples, multigrowth and staphylococci were not or rarely detected. RT-qPCR was more sensitive and showed higher bacterial positivity in all samples. Relative amounts of intestinal bacterial DNA (bifidobacteria, bacteroides, enterobacter, clostridia) increased with time. Sterility of blood samples was low during the studied time periods (1-7 days). The best postmortem microbiological sampling sites were pericardial fluid and liver up to 5 days after death.

  9. Microbiote intestinal et lipides : impact sur la santé humaine

    Directory of Open Access Journals (Sweden)

    Gérard Philippe

    2012-07-01

    Full Text Available The human intestine harbours a complex and diverse bacterial community called the gut microbiota. This microbiota, stable during the lifetime, is specific of each individual despite the existence of a phylogenetic core shared by the majority of adults. The influence of the gut microbiota on host’s physiology has been largely studied using germfree animals and recently it has been proposed that the gut microbiota affects nutrient acquisition, energy regulation and fat storage. Indeed, germfree animals are resistant to diet induced obesity and display low levels of blood and liver lipids. In humans, several grams of lipids reach the colon each day. These lipids have an impact on the gut microbiota composition characterized by an increase of the Firmicutes/ Bacteroides ratio. Concurrently, the gut microbiota is able to convert lipids, including fatty acids or cholesterol, leading to the production of metabolites with potential health effects.

  10. Effect of radiation-induced xerostomia on the human oral microflora. Report no. 12 (final), 1 Jul 1971-30 Jun 1976

    Energy Technology Data Exchange (ETDEWEB)

    Dreizen, S.; Brown, L.R.

    1976-06-30

    The caries-conducive impact of xerostomia was studied in 42 irradiated cancer patients. The radiation-induced xerostomia was paralleled by changes in the physical, microbial, biochemical, immunologic and dietary parameters of cariogenicity that collectively comprised an overwhelming caries challenge. Microbiologically, significant xerostomia-related increases in Strep. mutans, lactobacilli, staphylococci, yeasts and catalase-positive diphtheroids were accompanied by decreases in Strep. sanguis, bacteroides and fusobacteria in each of the 5 microenvironments tested. The scanty xerostomic saliva contained greater amounts of Na(+), Cl(-), Ca(++), Mg(++), Prot(-), lysozyme, IgA and IgG and considerably less HCO3(-). The increased concentrations of caries protective electrolytes and immunoproteins were negated by huge reductions in total daily saliva output. The xerostomia created caries challenge was almost completely neutralized by a preventive program of daily topical NaF applications and strict oral hygiene. (GRA)

  11. Human gut microbes impact host serum metabolome and insulin sensitivity

    DEFF Research Database (Denmark)

    Pedersen, Helle Krogh; Gudmundsdottir, Valborg; Nielsen, Henrik Bjørn

    2016-01-01

    Insulin resistance is a forerunner state of ischaemic cardiovascular disease and type 2 diabetes. Here we show how the human gut microbiome impacts the serum metabolome and associates with insulin resistance in 277 non-diabetic Danish individuals. The serum metabolome of insulin-resistant individ......Insulin resistance is a forerunner state of ischaemic cardiovascular disease and type 2 diabetes. Here we show how the human gut microbiome impacts the serum metabolome and associates with insulin resistance in 277 non-diabetic Danish individuals. The serum metabolome of insulin......-resistant individuals is characterized by increased levels of branched-chain amino acids (BCAAs), which correlate with a gut microbiome that has an enriched biosynthetic potential for BCAAs and is deprived of genes encoding bacterial inward transporters for these amino acids. Prevotella copri and Bacteroides vulgatus...

  12. Doxycycline sustained release from brushite cements for the treatment of periodontal diseases.

    Science.gov (United States)

    Tamimi, Faleh; Torres, Jesús; Bettini, Ruggero; Ruggera, Francesca; Rueda, Carmen; López-Ponce, Manuel; Lopez-Cabarcos, Enrique

    2008-06-01

    Doxycycline (DOXY) is a wide spectrum antibiotic used in the treatment of dental, periodontal, and bone infections. Brushite cements are calcium phosphate biomaterials especially interesting for bone regeneration processes. In this work, we describe the preparation of a brushite cement containing DOXY and the drug release from the cement. DOXY solutions were mixed with the cement powder and after a 50% burst release in the first 12 h, a slow and controlled release was achieved over 3.5 days. The release of DOXY hyclate was controlled by both, diffusion and Ca(2+) interaction. Formation of DOXY-Ca(2+) chelates was detected in the cement structure using solid state fluorescence. The brushite cement loaded with DOXY hyclate had antibacterial activity against periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides frosthytus. This new biomaterial may be helpful for the treatment of periodontal diseases.

  13. Temporomandibular Joint Septic Arthritis and Mandibular Osteomyelitis Arising From an Odontogenic Infection: A Case Report and Review of the Literature.

    Science.gov (United States)

    Gams, Kevin; Freeman, Phillip

    2016-04-01

    Septic arthritis of the temporomandibular joint (TMJ) has been infrequently reported in the literature. Some investigators believe that this condition is under-reported because it is underdiagnosed. Misdiagnosis or late diagnosis of this condition can lead to serious morbidity, including fistula formation, intracranial abscess, fibrous or bony ankylosis, temporal bone or condylar osteomyelitis, growth alteration, and several others. This report describes a case of septic TMJ arthritis arising from direct spread of an odontogenic infection with subsequent development of mandibular osteomyelitis. The purpose of this case report is to 1) increase awareness of an underdiagnosed condition, 2) establish the seriousness of this infection, 3) for the first time report on a case of TMJ septic arthritis caused by Bacteroides infection, and 4) provide a review of the relevant literature.

  14. Medical Surveillance Monthly Report, Volume 20, Number 8

    Science.gov (United States)

    2013-08-01

    septicemia (S. pneumoniae septicemia) 038.3 Septicemia due to anaerobes/bacteroides 003.1 Salmonella septicemia 022.3 Anthrax septicemia 036.2...0.1 -100 Salmonella septicemia 6 0.0 7 Unspecifi ed organism (total) 1,506 8.2 875 Other specifi ed septicemias 79 0.4 1,163 Unspecifi ed septicemia...Enterobacter cloacae 116 (5.6) 80 (6.8) 10 (3.4) 9 (3.2) 13 (5.1) 4 (7.4) Citrobacter spp . 83 (4.0) 57 (4.8) 6 (2.1) 9 (3.2) 8 (3.1) 3 (5.6) Pseudomonas spp

  15. Bacteriophages as viral indicators for radiation processing of water: a chemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Gehringer, Peter E-mail: peter.gehringer@arcs.ac.at; Eschweiler, Helmut; Leth, Hermann; Pribil, Walter; Pfleger, Silvia; Cabaj, Alexander; Haider, Thomas; Sommer, Regina

    2003-06-01

    Inactivation of the bacteriophages PHI X 174 (somatic coliphage), MS2 (F-specific coliphage) and B40-8 (phage infecting Bacteroides fragilis) suspended in tap water was studied applying gamma and electron beam irradiation as well. PHI X 174 phage was found to be a suitable viral indicator for water disinfection by means of ionizing radiation. The nutrient broths introduced simultaneously with the bacteriophages into the water when it is spiked with the phages for the experiments did not significantly change the scavenging capacity of the water matrix. No dose rate effect was observed with MS2 and B40-8 phages but PHI X 174 phage showed a clear dose rate effect. It was found that in water MS2 phage is significantly more sensitive to ionizing radiation than Escherichia coli.

  16. Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae, isolated compounds and semi-synthetic derivatives against endodontic bacteria

    Directory of Open Access Journals (Sweden)

    Fernanda M. dos Santos

    2012-06-01

    Full Text Available This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of b-amyrin, a-amyrin, and b-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis.

  17. Enterotypes influence temporal changes in gut microbiota

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Licht, Tine Rask; Kellebjerg Poulsen, Sanne

    The human gut microbiota plays an important role for the health of the host. The question is whether we can modulate the gut microbiota by changing diet. During a 6-month, randomised, controlled dietary intervention, the effect of a moderate diet shift from Average Danish Diet to New Nordic Diet...... on the gut microbiota in humans (n=62) was investigated. Quantitative PCR analysis showed that the microbiota did not change significantly by the intervention. Nevertheless, by stratifying subjects into two enterotypes, distinguished by the Prevotella/Bacteroides ratio (P/B), we were able to detect...... significant changes in the gut microbiota composition resulting from the interventions. Subjects with a high-P/B experienced more pronounced changes in the gut microbiota composition than subjects with a low-P/B. The study is the first to indicate that enterotypes influence microbiota response to a dietary...

  18. Enterotypes influence temporal changes in gut microbiota

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Licht, Tine Rask; Kellebjerg Poulsen, Sanne

    The human gut microbiota plays an important role for human health. The question is whether we can modulate the gut microbiota by changing diet. During a 6-month, randomised, controlled dietary intervention, the effect of consuming a diet following the New Nordic Diet recommendations (NND......) as opposed to Average Danish Diet (ADD) on the gut microbiota in humans (n=62) was investigated. Quantitative PCR analysis showed that the microbiota did not change significantly by the intervention. Nevertheless, by stratifying subjects into two enterotypes, distinguished by the Prevotella/Bacteroides ratio...... (P/B), we were able to detect significant changes in the gut microbiota composition resulting from the interventions. Subjects with a high-P/B experienced more pronounced changes in the gut microbiota composition than subjects with a low-P/B. The study is the first to indicate that enterotypes...

  19. COMPARATIVE ANALYSIS OF THE BACTERIAL POPULATION OF THE PROSTATE IN ITS CANCER AND BENIGN HYPERPLASIA

    Directory of Open Access Journals (Sweden)

    M. I. Kogan

    2011-01-01

    Full Text Available A bacteriological study of prostate biopsy specimens was conducted in patients with prostate benign hyperplasia (PBH and in those with prostate cancer (PC. It revealed a wide range of aerobic (Corynebacterium sp., Enterococcus sp., E. coli, S. haemolyticus, S. hominis and nonclostridial anaerobic (Bacteroides sp., Bifidobacterium sp., Eubacterium sp., Propionibacterium sp., Рeptococcus niger, Peptostreptococcus sp., Prevotella sp., Veilonella sp., Fusobacterium sp., Capnocytophaga ochracea, Streptococcus parvulus bacteria. Differences were seen in the detection rate of these microorganisms and in the level of tissue infectivity in PBH and PC. The average seeding of the prostate biopsy specimens and the detection rate of different types of bacteria in PBH were greater than those in PC; moreover, some bacteria were undetectable in PC at all.

  20. COMPARATIVE ANALYSIS OF THE BACTERIAL POPULATION OF THE PROSTATE IN ITS CANCER AND BENIGN HYPERPLASIA

    Directory of Open Access Journals (Sweden)

    M. I. Kogan

    2014-08-01

    Full Text Available A bacteriological study of prostate biopsy specimens was conducted in patients with prostate benign hyperplasia (PBH and in those with prostate cancer (PC. It revealed a wide range of aerobic (Corynebacterium sp., Enterococcus sp., E. coli, S. haemolyticus, S. hominis and nonclostridial anaerobic (Bacteroides sp., Bifidobacterium sp., Eubacterium sp., Propionibacterium sp., Рeptococcus niger, Peptostreptococcus sp., Prevotella sp., Veilonella sp., Fusobacterium sp., Capnocytophaga ochracea, Streptococcus parvulus bacteria. Differences were seen in the detection rate of these microorganisms and in the level of tissue infectivity in PBH and PC. The average seeding of the prostate biopsy specimens and the detection rate of different types of bacteria in PBH were greater than those in PC; moreover, some bacteria were undetectable in PC at all.

  1. Electricity generation from food wastes and microbial community structure in microbial fuel cells.

    Science.gov (United States)

    Jia, Jianna; Tang, Yu; Liu, Bingfeng; Wu, Di; Ren, Nanqi; Xing, Defeng

    2013-09-01

    Microbial fuel cell (MFC) was studied as an alternate and a novel way to dispose food wastes (FWs) in a waste-to-energy form. Different organic loading rate obviously affected the performance of MFCs fed with FWs. The maximum power density of ~18 W/m(3) (~556 mW/m(2)) was obtained at COD of 3200±400 mg/L and the maximum coulombic efficiency (CE) was ~27.0% at COD of 4900±350 mg/L. The maximum removals of COD, total carbohydrate (TC) and total nitrogen (TN) were ~86.4%, ~95.9% and ~16.1%, respectively. Microbial community analysis using 454 pyrosequencing of 16S rRNA gene demonstrated the combination of the dominant genera of the exoelectrogenic Geobacter and fermentative Bacteroides effectively drove highly efficient and reliable MFC systems with functions of organic matters degradation and electricity generation.

  2. [Postoperative necrotizing fasciitis: a rare and fatal complication].

    Science.gov (United States)

    Ghezala, Hassen Ben; Feriani, Najla

    2016-01-01

    Postoperative parietal complications can be exceptionally severe and serious threatening vital prognosis. Necrotizing fasciitis is a rare infection of the skin and deep subcutaneous tissues, spreading along fascia and adipose tissue. It is mainly caused by group A streptococcus (streptococcus pyogenes) but also by other bacteria such as Vibrio vulnificus, Clostridium perfringens or Bacteroides fragilis. Necrotizing fasciitis is a real surgical and medical emergency. We report, in this study, a very rare case of abdominal parietal gangrene occurring in a 75-year-old woman on the fifth day after surgery for an ovarian cyst. Evolution was marked by occurrence of a refractory septic shock with a rapidly fatal course on the third day of management.

  3. [Effects of nifuroxazide on fecal flora in healthy subjects].

    Science.gov (United States)

    Buisson, Y; Larribaud, J

    1989-01-01

    Effect of nifuroxazide on fecal flora was studied in 12 healthy volunteers receiving, in hazardous order and double-blind procedure, three six-days courses of treatment separated by eight-days spaces of time: the conventional dosage of 400 mg twice a day, a dosage of 1200 mg once a day, and placebo. Among six settled bacteriological index (wealth of the fecal flora, percentage of gram-negative bacteria, numbers of E. coli, Enterococcus, Clostridium and Bacteroides), no significant variation was found by means of statistical study between D0, D2 and D7, nor between the three courses of treatment. Therefore nifuroxazide, even in high dosage, does not injure integrity of microbial intestinal ecosystem under so defined experimental conditions, similar with clinical conditions.

  4. 血培养厌氧菌实验室鉴定%ANAEROBIC BLOOD CULTURE OF LABORATORY IDENTIFICATION

    Institute of Scientific and Technical Information of China (English)

    郭素芳; 王俊瑞; 范文斌; 福泉; 张军力

    2015-01-01

    目的::通过血培养厌氧菌病例的临床及实验室检测资料,掌握厌氧菌鉴定方法,探讨实验室开展厌氧菌检测的重要性。方法:观察血培养仪厌氧血培养瓶阳性报警曲线,转种厌氧血琼脂厌氧环境培养,观察茵落形态,涂片革兰氏染色,VITIE 2鉴定到种。结果:12份血培养出厌氧菌13株。其中2份为需氧菌和厌氧菌混合感染,分别是脆弱拟杆菌混合血液链球菌和中间链球菌;1份血培养分离出2种厌氧菌分别为脆弱拟杆菌和梭形梭菌;其他血培养分别培养出产气荚膜梭菌、脆弱拟杆菌、单形拟杆菌等。结论:厌氧菌感染多为混合感染,且培养、鉴定要求条件较高。加强对厌氧菌感染的认识和实验室检测,对临床诊断、治疗以及合理使用抗生素具有指导作用。%Objective:By the case of anaerobic blood culture of clinical and laboratory test data,to master anaerobes identification methods and explore the importance of laboratory testing of anaerobic bacteria. Methods:Observe positive anaerobic blood culture bottles alarm curve in blood culture system,turn kind of anaerobic blood agar and anaerobic environment to culture,observing colony mor-phology,smearing by Gram staln and using VITIE 2 identified to species. Results:There are 13 anaerobic bacteria stralns of 12 cases of blood culture. Including 2 cases of aerobic and anaerobic mixed infections,respectively are bacteroides fragilis mixed with Streptococcus sanguis and Streptococcus in-termadius. One case of blood culture isolate two kinds of anaerobic bacteria were Bacteroides fragilis and Clostridium fusiform. Other blood cultures were isolated clostridium perfringens, bacteroides fragilis,Bacteroides uniformis and so on. Conclusion:We conclude that anaerobic bacteria infections are mostly mixed infection, the culture and identification of anaerobic bacteria requires a higher condition. Enhance understanding of anaerobic infections

  5. Starch Catabolism by a Prominent Human Gut Symbiont Is Directed by the Recognition of Amylose Helices

    Energy Technology Data Exchange (ETDEWEB)

    Koropatkin, Nicole M.; Martens, Eric C.; Gordon, Jeffrey I.; Smith, Thomas J. (WU); (Danforth)

    2009-01-12

    The human gut microbiota performs functions that are not encoded in our Homo sapiens genome, including the processing of otherwise undigestible dietary polysaccharides. Defining the structures of proteins involved in the import and degradation of specific glycans by saccharolytic bacteria complements genomic analysis of the nutrient-processing capabilities of gut communities. Here, we describe the atomic structure of one such protein, SusD, required for starch binding and utilization by Bacteroides thetaiotaomicron, a prominent adaptive forager of glycans in the distal human gut microbiota. The binding pocket of this unique {alpha}-helical protein contains an arc of aromatic residues that complements the natural helical structure of starch and imposes this conformation on bound maltoheptaose. Furthermore, SusD binds cyclic oligosaccharides with higher affinity than linear forms. The structures of several SusD/oligosaccharide complexes reveal an inherent ligand recognition plasticity dominated by the three-dimensional conformation of the oligosaccharides rather than specific interactions with the composite sugars.

  6. Effect of Lactobacillus plantarum on disordered intestinal flora of mice introduced by antibiotics using PCR-DGGE technology%用DGGE技术分析植物乳杆菌对小鼠肠道菌群失调的影响

    Institute of Scientific and Technical Information of China (English)

    李艺; 孟镇; 钟其顶; 仇凯; 熊正河; 栾同青; 张泽生

    2013-01-01

    This article's aim was to adopt PCR-DGGE method to study the effect of feeding Lactobacillus plantarum to antibiotic intestinal flora in mice on the gut microflora.Female KM mice were continuously fed with cefdinir solution for five days to cause antibiotic-associated intestinal flora in them,and then treated by oral gavage of Lactobacillus plantarum(109CFU/mL) for another 5 days.Feces were abstracted and 16S rDNAbased PCR-DGGE method was used to analyze the influence of Lactobacillus plantarum adjustment process on the microbial community structure and diversity.The main preponderant strips were rubber cutting cloned and sequenced.PCR-DGGE profiles showed that with the extension of the Lactobacillus plantarum feeding time,the richness of the mouse intestinal flora presented a gradual increase in the successionprocess.The richness index(18) and diversity index(2.75) of the intestinal flora after the mice were gavaged using Lactobacillus plantarum for fourth day were the same as the normal ones.DGGE profiles,sequencing results showed that plant lactobacillus control mice intestinal dysbacteriosis mainly manifested in two aspects:selective increase beneficial bacteria such as Bacteroides stercoris,Bacteroides uniformis strain of quantity.Inhibition of pathogenic bacteria such as Clostridium clostridioforme,Pseudomonas stutzeri growth,etc.Results showed that the Lactobacillus plantarum had adjustment effect on intestinal flora disorder caused by cefdinir.Establishment of PCR-DGGE method analysis methods were in order to monitor the dynamic changes of intestinal flora,and to lay the foundation for further study of probiotics on the mechanism of action of the intestinal flora.%采用PCR-DGGE方法研究植物乳杆菌对小鼠肠道失调菌群微生态的影响.选用昆明雌性小鼠建立小鼠抗生素相关性菌群失调模型,灌服植物乳杆菌菌液(109CFU/mL)5d,分离提取小鼠粪便中微生物群落的DNA,通过PCRDGGE技术分析植物乳杆菌调节

  7. A conformational switch in the active site of BT_2972, a methyltransferase from an antibiotic resistant pathogen B. thetaiotaomicron.

    Directory of Open Access Journals (Sweden)

    Veerendra Kumar

    Full Text Available Methylation is one of the most common biochemical reactions involved in cellular and metabolic functions and is catalysed by the action of methyltransferases. Bacteroides thetaiotaomicron is an antibiotic-resistant bacterium that confers resistance through methylation, and as yet, there is no report on the structure of methyltransferases from this bacterium. Here, we report the crystal structure of an AdoMet-dependent methyltransferase, BT_2972 and its complex with AdoMet and AdoHcy for B. thetaiotaomicron VPI-5482 strain along with isothermal titration calorimetric assessment of the binding affinities. Comparison of the apo and complexed BT_2972 structures reveals a significant conformational change between open and closed forms of the active site that presumably regulates the association with cofactors and may aid interaction with substrate. Together, our analysis suggests that BT_2972 is a small molecule methyltransferase and might catalyze two O-methylation reaction steps involved in the ubiquinone biosynthesis pathway.

  8. Localization of acid phosphatase activity in the apoplast of root nodules of pea (Pisum sativum

    Directory of Open Access Journals (Sweden)

    Marzena Sujkowska

    2011-01-01

    Full Text Available Changes in the activity of acid phosphatase (AcPase in the apoplast of pea root nodule were investigated. The activity was determined using lead and cerium methods. The results indicated a following sequence of AcPase activity appearance during the development of the infection thread: 1 low AcPase activity appears in the outer part of cells of symbiotic bacteria; 2 bacteria show increased AcPase activity, and the enzyme activity appears in the thread walls; 3 activity exhibits also matrix of the infection thread; 4 bacteria just before their release from the infection threads show high AcPase activity; 5 AcPase activity ceases after bacteria transformation into bacteroids. The increase in bacterial AcPase activity may reflect a higher demand for inorganic phosphorus necessary for propagation of the bacteria within the infection threads and/or involved in bacteria release from the infection threads.

  9. In vitro fermentation by human gut bacteria of proteolytically digested caseinomacropeptide nonenzymatically glycosylated with prebiotic carbohydrates.

    Science.gov (United States)

    Hernandez-Hernandez, Oswaldo; Sanz, M Luz; Kolida, Sofia; Rastall, Robert A; Moreno, F Javier

    2011-11-23

    The in vitro fermentation selectivity of hydrolyzed caseinomacropeptide (CMP) glycosylated, via Maillard reaction (MR), with lactulose, galacto-oligosaccharides from lactose (GOSLa), and galacto-oligosaccharides from lactulose (GOSLu) was evaluated, using pH-controlled small-scale batch cultures at 37 °C under anaerobic conditions with human feces. After 10 and 24 h of fermentation, neoglyconjugates exerted a bifidogenic activity, similar to those of the corresponding prebiotic carbohydrates. No significant differences were found in Bacteroides , Lactobacillus - Enterococcus , Clostridium histolyticum subgroup, Atopobium and Clostridium coccoides - Eubacterium rectale populations. Concentrations of lactic acid and short-chain fatty acids (SCFA) produced during the fermentation of prebiotic carbohydrates were similar to those produced for their respective neoglycoconjugates at both fermentation times. These findings, joined with the functional properties attributed to CMP, could open up new applications of MR products involving prebiotics as novel multiple-functional ingredients with potential beneficial effects on human health.

  10. Dicty_cDB: Contig-U06548-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 3( CP001359 |pid:none) Anaeromyxobacter dehalogenans 2C... 86 2e-15 AF205887_1( AF205887 |pid:none) Leishmania donovani peroxido...Bacteroides fragilis YCH46 DNA,... 85 2e-15 AF134161_1( AF134161 |pid:none) Leishmania chagasi peroxidoxin 1...971 |pid:none) Finegoldia magna ATCC 29328 DNA,... 84 7e-15 AF312397_1( AF312397 |pid:none) Leishmania chagasi peroxido...5 AF312398_1( AF312398 |pid:none) Leishmania chagasi peroxidoxin 3 (... 84 7e-15 ...anella halifaxensis HAW-EB4... 84 7e-15 DQ071681_1( DQ071681 |pid:none) Leishmania aethiopica peroxidoxin ..

  11. Effects of bitter melon (Momordica charantia L.) on the gut microbiota in high fat diet and low dose streptozocin-induced rats.

    Science.gov (United States)

    Zhu, Ying; Bai, Juan; Zhang, Yi; Xiao, Xiang; Dong, Ying

    2016-09-01

    The effects on gut microbiota of type 2 diabetic rats fed a bitter melon formulation (BLSP, a lyophilized superfine powder) were investigated. BLSP treatment significantly reduced fasting blood glucose levels (p microbiota of treated and control rats were profiled by PCR amplification and pyrosequencing of 16S rRNA genes (V3-V9 region). BLSP significantly reduced the ratio of Firmicutes to Bacteroidetes in diabetic rats, while the relative abundances of Ruminococcaceae, Bacteroides and Ruminococcus were significantly lowered in BLSP-treated rats compared to diabetic rats. Additionally, BLSP significantly suppressed the activation of MAPK (JNK and p38). The results indicate that BLSP can significantly modify the proportions of particular gut microbiota in diabetic rats without disturbing the normal population diversity. By suppressing the activation of MAPK signaling pathway, a BLSP containing diet may ameliorate type 2 diabetes.

  12. [A Case of Hyperammonemia Caused by Urinary Tract Infection Due to Urease-Producing Bacteria].

    Science.gov (United States)

    Emura, Masahiro; Tsuchihashi, Kazunari; Shimizu, Yosuke; Kanamaru, Sojun; Matoba, Shun; Ito, Noriyuki

    2016-08-01

    We present here a rare case of hyperammonemia without liver dysfunction or portal-systemic shunting. The patient was an 80-year-old woman with a history of neurogenic bladder. She was admitted to a nearby hospital for vomiting, diarrhea and consciousness disturbance. Two days after admission, she was transferred to our hospital because of persistant consciousness disturbance. Laboratory data revealed hyperammonemia, but there was no indication of liver dysfunction. Moreover abdominal computed tomography did not reveal any clear finding of liver disease or portal-systemic shunting, but we noted multiple large bladder diverticula. Antibiotic therapy, tracheal intubation, ventilator management and bladder catheterization were performed. The patient's level of consciousness improved rapidly. Urinary culture revealed Bacteroides ureolyticus (urease-producing bacteria). The patient was diagnosed with hyperammonemia and a urinary tract infection due to urease-producing bacteria. Thus, physicians should be aware that obstructive urinary tract infections due to urease-producing bacteria can also be the cause of hyperammonemia.

  13. Characteristics of enriched cultures for bio-huff-`n`-puff tests at Jilin oil field

    Energy Technology Data Exchange (ETDEWEB)

    Xiu-Yuan Wang; Gang Dai; Yan-Fen Xue; Shu-Hua Xie [Institute of Microbiology, Beijing (China)] [and others

    1995-12-31

    Three enriched cultures (48, 15a, and 26a), selected from more than 80 soil and water samples, could grow anaerobically in the presence of crude oil at 30{degrees}C and could ferment molasses to gases and organic acids. Oil recovery by culture 48 in the laboratory model experiment was enhanced by 25.2% over the original reserves and by 53.7% over the residual reserves. Enriched culture 48 was composed of at least 4 species belonging to the genera Eubacterium, Fusobacterium, and Bacteroides. This enriched culture was used as inoculum for MEOR field trials at Jilin oil field with satisfactory results. The importance of the role of these isolates in EOR was confirmed by their presence and behavior in the fluids produced from the microbiologically treated reservoir.

  14. Relationships between Nitrate and Oxygen Supply in Symbiotic Nitrogen Fixation by White Clover

    DEFF Research Database (Denmark)

    Minchin, F. R.; Ines Minguez, M.; Sheedy, J. E.;

    1986-01-01

    in nitrogenase-linked respiration and a 340% increase in growth and maintenance respiration. Carbon costs of nitrogenase activity (mol CO2 respired per mol C2H4 produced) increased by 45% over the exposure period. Sucrose content of the nodules decreased, but the pattern of decrease did not correlate......Exposure of mature, nodulated plants of white clover (Trifolium repens) cv. Blanca to 330 mg dm−3 NO3-N for 8 d caused nitrogenase activity per plant to decrease by 80%. Total nodulated root respiration was not significantly affected but analysis of its components showed an 81% decrease...... with that of nitrogenase activity. The oxygen diffusion resistance of the nodules was increased by a factor of five. Characterization of this resistance increase suggests an abnormal modification of the diffusion barrier and it is concluded that alteration in the oxygen supply to the bacteroids is involved in the effect...

  15. Inhibitory activity of Aloe vera gel on some clinically isolated cariogenic and periodontopathic bacteria.

    Science.gov (United States)

    Fani, Mohammadmehdi; Kohanteb, Jamshid

    2012-03-01

    Aloe vera is a medicinal plant with anti-inflammatory, antimicrobial, antidiabetic and immune-boosting properties. In the present study we investigated the inhibitory activities of Aloe vera gel on some cariogenic (Streptococcus mutans), periodontopathic (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis) and an opportunistic periodontopathogen (Bacteroides fragilis) isolated from patients with dental caries and periodontal diseases. Twenty isolates of each of these bacteria were investigated for their sensitivity to Aloe vera gel using the disk diffusion and microdilution methods. S. mutans was the species most sensitive to Aloe vera gel with a MIC of 12.5 µg/ml, while A. actinomycetemcomitans, P. gingivalis, and B. fragilis were less sensitive, with a MIC of 25-50 µg/ml (P Aloe vera gel at optimum concentration could be used as an antiseptic for prevention of dental caries and periodontal diseases.

  16. Regulation of symbiotic nitrogen fixation in root nodules of alfalfa (Medicago sativa) infected with Rhizobium meliloti.

    Science.gov (United States)

    Kamberger, W

    1977-10-24

    Symbiotic nitrogen fixation of Rhizobium meliloti bacteroids in Medicago sativa root nodules was suppressed by several inorganic nitrogen sources. Amino acids like glutamine, glutamic acid and aspartic acid, which can serve as sole nitrogen sources for the unnodulated plant did not influence nitrogenase activity of effective nodules, even at high concetrations. Ammonia and nitrate suppressed symbiotic nitrogen fixation in vivo only at concentrations much higher than those needed for suppression of nitrogenase activity in free living nitrogen fixing bacteria. The kinetics of suppression were slow compared with that of free living nitrogen fixing bacteria. On the other hand, nitrite, which acts as a direct inhibitor of nitrogenase, suppressed very quickly and at low concentrations. Glutamic acid and glutamine enhanced the effect of ammonia dramatically, while the suppression by nitrate was enhanced only slightly.

  17. Glycan complexity dictates microbial resource allocation in the large intestine

    Science.gov (United States)

    Rogowski, Artur; Briggs, Jonathon A.; Mortimer, Jennifer C.; Tryfona, Theodora; Terrapon, Nicolas; Lowe, Elisabeth C.; Baslé, Arnaud; Morland, Carl; Day, Alison M.; Zheng, Hongjun; Rogers, Theresa E.; Thompson, Paul; Hawkins, Alastair R.; Yadav, Madhav P.; Henrissat, Bernard; Martens, Eric C.; Dupree, Paul; Gilbert, Harry J.; Bolam, David N.

    2015-01-01

    The structure of the human gut microbiota is controlled primarily through the degradation of complex dietary carbohydrates, but the extent to which carbohydrate breakdown products are shared between members of the microbiota is unclear. We show here, using xylan as a model, that sharing the breakdown products of complex carbohydrates by key members of the microbiota, such as Bacteroides ovatus, is dependent on the complexity of the target glycan. Characterization of the extensive xylan degrading apparatus expressed by B. ovatus reveals that the breakdown of the polysaccharide by the human gut microbiota is significantly more complex than previous models suggested, which were based on the deconstruction of xylans containing limited monosaccharide side chains. Our report presents a highly complex and dynamic xylan degrading apparatus that is fine-tuned to recognize the different forms of the polysaccharide presented to the human gut microbiota. PMID:26112186

  18. Emphysematous pyelonephritis in failed renal allograft: Case report and review of literature.

    Science.gov (United States)

    Bansal, Rahul Kumar; Lambe, Shahid; Kapoor, Anil

    2016-01-01

    Emphysematous pyelonephritis (EPN) in renal allograft is rare but potentially lethal complication and requires aggressive medical and/or surgical therapy to achieve cure. We report a case of 60-year-old diabetic male with poor cardiac function on maintenance hemodialysis, who underwent delayed allograft nephrectomy for EPN in failed renal allograft. Blood culture grew Bacteroides. He was stable in the postoperative period but passed away on day 4 due to myocardial infarction likely secondary to poor baseline cardiac function. Delay in diagnosis and treatment could have contributed to this unfavorable outcome. There is a paucity of published literature regarding EPN in the transplant population, such that management decisions (percutaneous conservative versus urgent surgical) are challenging. Further studies are required to establish treatment guidelines.

  19. [Qualitative and quantitative detection of bacterial flora in experimental blind loop syndrome of the rat].

    Science.gov (United States)

    Menge, H; Simes, G; Germer, C T; Wagner, J; Hahn, H; Riecken, E O

    1985-08-01

    In the blind loop syndrome bacterial overgrowth--accompanied by an increase in bile acid deconjugation--is thought to be responsible for the observed morphological alterations of the small intestinal mucosa with its concomitant malabsorption syndrome. Since in this chain of events the bacterial overgrowth is of primary importance, we have performed a complete qualitative and quantitative evaluation of the intraluminal flora in rats with surgically created self-filling blind loops. The results show a significant increase in bacteria of the aerobic growing genera E. coli and Streptococcus (Enterococcus), and of the anaerobic growing genus Bacteroides, in one single rat also of the genera Lactobacillus/Bifidobacterium. In order to elucidate which strains of bacteria are predominantly responsible for the morphological and functional alterations observed in the stagnant loop syndrome, germ-free rats with self-filling blind loops should be contaminated selectively with bacteria of these genera.

  20. Determination of reactive oxygen generated from natural medicines and their antibacterial activity$

    Institute of Scientific and Technical Information of China (English)

    Noriko Tajima; Makiko Takasaki; Haruka Fukamachi; Takeshi Igarashi; Yoshijiro Nakajima; Hidetoshi Arakawa

    2016-01-01

    Extracts of 16 natural medicine powders (Galla chinensis, Malloti cortex, Cassiae semen, Sophorae radix, Myricae cortex, Crataegi fructus, Gambir, Mume fructus, Geranii herba, Phellodendri cortex, Coptidis rhizoma, Swertiae herba, and Cinnamomi cortex) were assayed for reactive oxygen concentrations using the per-oxyoxalate chemiluminescent detection system. High luminescence intensity was observed in Galla chinensis, Geranii herba, Malloti cortex, Myricae cortex, and Cinnamomi cortex. Additional experiments identified the reactive oxygen species as hydrogen peroxide. Galla chinensis generated 2.4 ? 10 ? 4 mol/L hydrogen peroxide from a 1 mg/mL solution. In bacterial growth tests, Galla chinensis extract had antibacterial activity against Escherichia coli, Staphylococcus aureus, Bacteroides thetaiotaomicron, Campylobacter sputorum biovar sputorum, Streptococcus salivarius thermophilus, Lactobacillus casei, and Bifidobacterium longum infantis. This antibacterial activity was de-creased by the addition of catalase. It revealed that hydrogen peroxide which Galla chinensis produced participated in antibacterial activity.

  1. Performance of viruses and bacteriophages for fecal source determination in a multi-laboratory, comparative study.

    Science.gov (United States)

    Harwood, Valerie J; Boehm, Alexandria B; Sassoubre, Lauren M; Vijayavel, Kannappan; Stewart, Jill R; Fong, Theng-Theng; Caprais, Marie-Paule; Converse, Reagan R; Diston, David; Ebdon, James; Fuhrman, Jed A; Gourmelon, Michele; Gentry-Shields, Jennifer; Griffith, John F; Kashian, Donna R; Noble, Rachel T; Taylor, Huw; Wicki, Melanie

    2013-11-15

    An inter-laboratory study of the accuracy of microbial source tracking (MST) methods was conducted using challenge fecal and sewage samples that were spiked into artificial freshwater and provided as unknowns (blind test samples) to the laboratories. The results of the Source Identification Protocol Project (SIPP) are presented in a series of papers that cover 41 MST methods. This contribution details the results of the virus and bacteriophage methods targeting human fecal or sewage contamination. Human viruses used as source identifiers included adenoviruses (HAdV), enteroviruses (EV), norovirus Groups I and II (NoVI and NoVII), and polyomaviruses (HPyVs). Bacteriophages were also employed, including somatic coliphages and F-specific RNA bacteriophages (FRNAPH) as general indicators of fecal contamination. Bacteriophage methods targeting human fecal sources included genotyping of FRNAPH isolates and plaque formation on bacterial hosts Enterococcus faecium MB-55, Bacteroides HB-73 and Bacteroides GB-124. The use of small sample volumes (≤50 ml) resulted in relatively insensitive theoretical limits of detection (10-50 gene copies or plaques × 50 ml(-1)) which, coupled with low virus concentrations in samples, resulted in high false-negative rates, low sensitivity, and low negative predictive values. On the other hand, the specificity of the human virus methods was generally close to 100% and positive predictive values were ∼40-70% with the exception of NoVs, which were not detected. The bacteriophage methods were generally much less specific toward human sewage than virus methods, although FRNAPH II genotyping was relatively successful, with 18% sensitivity and 85% specificity. While the specificity of the human virus methods engenders great confidence in a positive result, better concentration methods and larger sample volumes must be utilized for greater accuracy of negative results, i.e. the prediction that a human contamination source is absent.

  2. Throwing the dice for the diagnosis of vaginal complaints?

    Directory of Open Access Journals (Sweden)

    Taras David

    2006-02-01

    Full Text Available Abstract Backround Vaginitis is among the most common conditions women are seeking medical care for. Although these infections can easily be treated, the relapse rate is high. This may be due to inadequate use of the diagnostic potential. Methods We evaluated the misjudgement rate of the aetiology of vaginal complaints. A total of 220 vaginal samples from women with a vaginal complaint were obtained and analysed for numbers of total lactobacilli, H2O2-producing lactobacilli, total aerobic cell counts and total anaerobic cell counts including bifidobacteria, Bacteroides spp., Prevotella spp. Additionally, the presence of Atopobium vaginae, Gardnerella vaginalis, Candida spp. and Trichomonas vaginalis was evaluated by DNA-hybridisation using the PCR and Affirm VPIII Microbial Identification Test, respectively. Results The participating physicians diagnosed Bacterial vaginosis (BV as origin of discomfort in 80 cases, candidiasis in 109 cases and mixed infections in 8 cases. However, a present BV, defined as lack of H2O2-lactobacilli, presence of marker organisms, such as G. vaginalis, Bacteroides spp. or Atopobium vaginae, and an elevated pH were identified in only 45 cases of the women examined. Candida spp. were detected in 46 cases. Interestingly, an elevated pH corresponded solely to the presence of Atopobium vaginae, which was detected in 11 cases. Conclusion Errors in the diagnosis of BV and candida vulvovaginitis (CV were high. Interestingly, the cases of misjudgement of CV (77% were more numerous than that of BV (61%. The use of Amsel criteria or microscopy did not reduce the number of misinterpretations. The study reveals that the misdiagnosis of vaginal complaints is rather high.

  3. TLA-1: a new plasmid-mediated extended-spectrum beta-lactamase from Escherichia coli.

    Science.gov (United States)

    Silva, J; Aguilar, C; Ayala, G; Estrada, M A; Garza-Ramos, U; Lara-Lemus, R; Ledezma, L

    2000-04-01

    Escherichia coli R170, isolated from the urine of an infected patient, was resistant to expanded-spectrum cephalosporins, aztreonam, ciprofloxacin, and ofloxacin but was susceptible to amikacin, cefotetan, and imipenem. This particular strain contained three different plasmids that encoded two beta-lactamases with pIs of 7.0 and 9.0. Resistance to cefotaxime, ceftazidime, aztreonam, trimethoprim, and sulfamethoxazole was transferred by conjugation from E. coli R170 to E. coli J53-2. The transferred plasmid, RZA92, which encoded a single beta-lactamase, was 150 kb in length. The cefotaxime resistance gene that encodes the TLA-1 beta-lactamase (pI 9.0) was cloned from the transconjugant by transformation to E. coli DH5alpha. Sequencing of the bla(TLA-1) gene revealed an open reading frame of 906 bp, which corresponded to 301 amino acid residues, including motifs common to class A beta-lactamases: (70)SXXK, (130)SDN, and (234)KTG. The amino acid sequence of TLA-1 shared 50% identity with the CME-1 chromosomal class A beta-lactamase from Chryseobacterium (Flavobacterium) meningosepticum; 48.8% identity with the VEB-1 class A beta-lactamase from E. coli; 40 to 42% identity with CblA of Bacteroides uniformis, PER-1 of Pseudomonas aeruginosa, and PER-2 of Salmonella typhimurium; and 39% identity with CepA of Bacteroides fragilis. The partially purified TLA-1 beta-lactamase had a molecular mass of 31.4 kDa and a pI of 9.0 and preferentially hydrolyzed cephaloridine, cefotaxime, cephalothin, benzylpenicillin, and ceftazidime. The enzyme was markedly inhibited by sulbactam, tazobactam, and clavulanic acid. TLA-1 is a new extended-spectrum beta-lactamase of Ambler class A.

  4. TLA-1: a New Plasmid-Mediated Extended-Spectrum β-Lactamase from Escherichia coli

    Science.gov (United States)

    Silva, J.; Aguilar, C.; Ayala, G.; Estrada, M. A.; Garza-Ramos, U.; Lara-Lemus, R.; Ledezma, L.

    2000-01-01

    Escherichia coli R170, isolated from the urine of an infected patient, was resistant to expanded-spectrum cephalosporins, aztreonam, ciprofloxacin, and ofloxacin but was susceptible to amikacin, cefotetan, and imipenem. This particular strain contained three different plasmids that encoded two β-lactamases with pIs of 7.0 and 9.0. Resistance to cefotaxime, ceftazidime, aztreonam, trimethoprim, and sulfamethoxazole was transferred by conjugation from E. coli R170 to E. coli J53-2. The transferred plasmid, RZA92, which encoded a single β-lactamase, was 150 kb in length. The cefotaxime resistance gene that encodes the TLA-1 β-lactamase (pI 9.0) was cloned from the transconjugant by transformation to E. coli DH5α. Sequencing of the blaTLA-1 gene revealed an open reading frame of 906 bp, which corresponded to 301 amino acid residues, including motifs common to class A β-lactamases: 70SXXK, 130SDN, and 234KTG. The amino acid sequence of TLA-1 shared 50% identity with the CME-1 chromosomal class A β-lactamase from Chryseobacterium (Flavobacterium) meningosepticum; 48.8% identity with the VEB-1 class A β-lactamase from E. coli; 40 to 42% identity with CblA of Bacteroides uniformis, PER-1 of Pseudomonas aeruginosa, and PER-2 of Salmonella typhimurium; and 39% identity with CepA of Bacteroides fragilis. The partially purified TLA-1 β-lactamase had a molecular mass of 31.4 kDa and a pI of 9.0 and preferentially hydrolyzed cephaloridine, cefotaxime, cephalothin, benzylpenicillin, and ceftazidime. The enzyme was markedly inhibited by sulbactam, tazobactam, and clavulanic acid. TLA-1 is a new extended-spectrum β-lactamase of Ambler class A. PMID:10722503

  5. Alterations of the Ileal and Colonic Mucosal Microbiota in Canine Chronic Enteropathies.

    Directory of Open Access Journals (Sweden)

    Eric Cassmann

    Full Text Available The intestinal microbiota is increasingly linked to the pathogenesis of chronic enteropathies (CE in dogs. While imbalances in duodenal and fecal microbial communities have been associated with mucosal inflammation, relatively little is known about alterations in mucosal bacteria seen with CE involving the ileum and colon.To investigate the composition and spatial organization of mucosal microbiota in dogs with CE and controls.Tissue sections from endoscopic biopsies of the ileum and colon from 19 dogs with inflammatory bowel disease (IBD, 6 dogs with granulomatous colitis (GC, 12 dogs with intestinal neoplasia, and 15 controls were studied by fluorescence in situ hybridization (FISH on a quantifiable basis.The ileal and colonic mucosa of healthy dogs and dogs with CE is predominantly colonized by bacteria localized to free and adherent mucus compartments. CE dogs harbored more (P < 0.05 mucosal bacteria belonging to the Clostridium-coccoides/Eubacterium rectale group, Bacteroides, Enterobacteriaceae, and Escherichia coli versus controls. Within the CE group, IBD dogs had increased (P < 0.05 Enterobacteriaceae and E. coli bacteria attached onto surface epithelia or invading within the intestinal mucosa. Bacterial invasion with E. coli was observed in the ileal and colonic mucosa of dogs with GC (P < 0.05. Dogs with intestinal neoplasia had increased (P < 0.05 adherent (total bacteria, Enterobacteriaceae, E. coli and invasive (Enterobacteriaceae, E. coli, and Bacteroides bacteria in biopsy specimens. Increased numbers of total bacteria adherent to the colonic mucosa were associated with clinical disease severity in IBD dogs (P < 0.05.Pathogenic events in canine CE are associated with different populations of the ileal and colonic mucosal microbiota.

  6. In silico insights into the symbiotic nitrogen fixation in Sinorhizobium meliloti via metabolic reconstruction.

    Directory of Open Access Journals (Sweden)

    Hansheng Zhao

    Full Text Available BACKGROUND: Sinorhizobium meliloti is a soil bacterium, known for its capability to establish symbiotic nitrogen fixation (SNF with leguminous plants such as alfalfa. S. meliloti 1021 is the most extensively studied strain to understand the mechanism of SNF and further to study the legume-microbe interaction. In order to provide insight into the metabolic characteristics underlying the SNF mechanism of S. meliloti 1021, there is an increasing demand to reconstruct a metabolic network for the stage of SNF in S. meliloti 1021. RESULTS: Through an iterative reconstruction process, a metabolic network during the stage of SNF in S. meliloti 1021 was presented, named as iHZ565, which accounts for 565 genes, 503 internal reactions, and 522 metabolites. Subjected to a novelly defined objective function, the in silico predicted flux distribution was highly consistent with the in vivo evidences reported previously, which proves the robustness of the model. Based on the model, refinement of genome annotation of S. meliloti 1021 was performed and 15 genes were re-annotated properly. There were 19.8% (112 of the 565 metabolic genes included in iHZ565 predicted to be essential for efficient SNF in bacteroids under the in silico microaerobic and nutrient sharing condition. CONCLUSIONS: As the first metabolic network during the stage of SNF in S. meliloti 1021, the manually curated model iHZ565 provides an overview of the major metabolic properties of the SNF bioprocess in S. meliloti 1021. The predicted SNF-required essential genes will facilitate understanding of the key functions in SNF and help identify key genes and design experiments for further validation. The model iHZ565 can be used as a knowledge-based framework for better understanding the symbiotic relationship between rhizobia and legumes, ultimately, uncovering the mechanism of nitrogen fixation in bacteroids and providing new strategies to efficiently improve biological nitrogen fixation.

  7. Role of symbiotic auxotrophy in the Rhizobium-legume symbioses.

    Directory of Open Access Journals (Sweden)

    Jurgen Prell

    Full Text Available Rhizobium leguminosarum bv. viciae mutants unable to transport branched-chain amino acids via the two main amino acid ABC transport complexes AapJQMP and BraDEFGC produce a nitrogen starvation phenotype when inoculated on pea (Pisum sativum plants [1], [2]. Bacteroids in indeterminate pea nodules have reduced abundance and a lower chromosome number. They reduce transcription of pathways for branched-chain amino acid biosynthesis and become dependent on their provision by the host. This has been called "symbiotic auxotrophy".A region important in solute specificity was identified in AapQ and changing P144D in this region reduced branched-chain amino acid transport to a very low rate. Strains carrying P144D were still fully effective for N(2 fixation on peas demonstrating that a low rate of branched amino acid transport in R. leguminosarum bv. viciae supports wild-type rates of nitrogen fixation. The importance of branched-chain amino acid transport was then examined in other legume-Rhizobium symbioses. An aap bra mutant of R. leguminosarum bv. phaseoli also showed nitrogen starvation symptoms when inoculated on French bean (Phaseolus vulgaris, a plant producing determinate nodules. The phenotype is different from that observed on pea and is accompanied by reduced nodule numbers and nitrogen fixation per nodule. However, an aap bra double mutant of Sinorhizobium meliloti 2011 showed no phenotype on alfalfa (Medicago sativa.Symbiotic auxotrophy occurs in both determinate pea and indeterminate bean nodules demonstrating its importance for bacteroid formation and nodule function in legumes with different developmental programmes. However, only small quantities of branched chain amino acids are needed and symbiotic auxotrophy did not occur in the Sinorhizobium meliloti-alfalfa symbiosis under the conditions measured. The contrasting symbiotic phenotypes of aap bra mutants inoculated on different legumes probably reflects altered timing of amino acid

  8. Water quality, weather and environmental factors associated with fecal indicator organism density in beach sand at two recreational marine beaches

    Science.gov (United States)

    Heaney, Christopher D.; Exum, Natalie G.; Dufour, Alfred P.; Brenner, Kristen P.; Haugland, Richard A.; Chern, Eunice; Schwab, Kellogg J.; Love, David C.; Serre, Marc L.; Noble, Rachel; Wade, Timothy J.

    2015-01-01

    Recent studies showing an association between fecal indicator organisms (FIOs) in sand and gastrointestinal (GI) illness among beachgoers with sand contact have important public health implications because of the large numbers of people who recreate at beaches and engage in sand contact activities. Yet, factors that influence fecal pollution in beach sand remain unclear. During the 2007 National Epidemiological and Environmental Assessment of Recreational (NEEAR) Water Study, sand samples were collected at three locations (60 m apart) on weekend days (Sat, Sun) and holidays between June and September at two marine beaches — Fairhope Beach, AL and Goddard Beach, RI — with nearby publicly-owned treatment works (POTWs) outfalls. F+ coliphage, enterococci, Bacteroidales, fecal Bacteroides spp., and Clostridium spp. were measured in sand using culture and qPCR-based calibrator-cell equivalent methods. Water samples were also collected on the same days, times and transects as the 144 sand samples and were assayed using the same FIO measurements. Weather and environmental data were collected at the time of sample collection. Mean FIO concentrations in sand varied over time, but not space. Enterococci CFU and CCE densities in sand were not correlated, although other FIOs in sand were. The strongest correlation between FIO density in sand and water was fecal Bacteroides CCE, followed by enterococci CFU, Clostridium spp. CCE, and Bacteroidales CCE. Overall, the factors associated with FIO concentrations in sand were related to the sand–water interface (i.e., sand-wetting) and included daily average densities of FIOs in water, rainfall, and wave height. Targeted monitoring that focuses on daily trends of sand FIO variability, combined with information about specific water quality, weather, and environmental factors may inform beach monitoring and management decisions to reduce microbial burdens in beach sand. The views expressed in this paper are those of the authors

  9. Impact of Surotomycin on the Gut Microbiota of Healthy Volunteers in a Phase 1 Clinical Trial.

    Science.gov (United States)

    Citron, Diane M; Tyrrell, Kerin L; Dale, Suzanne E; Chesnel, Laurent; Goldstein, Ellie J C

    2016-04-01

    Clostridium difficile-associated diarrhea has been associated with disruption of the normal intestinal microbiota, particularly theBacteroides fragilisgroup andPrevotellaspecies. Surotomycin is a bactericidal cyclic lipopeptide in development for treatment ofClostridium difficile-associated diarrhea that has selective and potent activity againstC. difficileand other Gram-positive bacteria and a minimal impact on intestinal Gram-negative organisms. The impacts of ascending doses of surotomycin on major organism groups in the gut microbiota of healthy volunteers were evaluated during a randomized, double-blind, placebo-controlled, multiple-dose phase 1 study. Thirty volunteers were randomized into 3 cohorts, using a 4:1 ratio, to receive 250 mg, 500 mg, or 1,000 mg of surotomycin, or placebo, twice daily for 14 days. Stool samples collected at baseline (days 0 and 1) and at the end of treatment (days 13 to 15) were cultured quantitatively. TheB. fragilisgroup, theBacteroides/Prevotellagroup, andEnterobacteriaceaewere also quantified by quantitative real-time PCR. Baseline and end-of-treatment stool samples showed 1- to 2-log10CFU/g reductions in total bacterial counts for most volunteers. Various decreases in clostridial,Lactobacillus-Bifidobacteriumgroup, and enterococcus-streptococcus group counts occurred while patients were receiving surotomycin, whereas the enterobacteria and theB. fragilisgroup persisted at the end of treatment. There was no change in enterococcus MICs of surotomycin, nor was vancomycin-resistantEnterococcusdetected after exposure. Surotomycin at doses of up to 1,000 mg twice daily had only modest disruptive effects on the gut microbiota. The potential sparing of the gut microbiota by surotomycin may decrease the risk of disease recurrence.

  10. Characterization of a Mesorhizobium loti α-Type Carbonic Anhydrase and Its Role in Symbiotic Nitrogen Fixation▿

    Science.gov (United States)

    Kalloniati, Chrysanthi; Tsikou, Daniela; Lampiri, Vasiliki; Fotelli, Mariangela N.; Rennenberg, Heinz; Chatzipavlidis, Iordanis; Fasseas, Costas; Katinakis, Panagiotis; Flemetakis, Emmanouil

    2009-01-01

    Carbonic anhydrase (CA) (EC 4.2.1.1) is a widespread enzyme catalyzing the reversible hydration of CO2 to bicarbonate, a reaction that participates in many biochemical and physiological processes. Mesorhizobium loti, the microsymbiont of the model legume Lotus japonicus, possesses on the symbiosis island a gene (msi040) encoding an α-type CA homologue, annotated as CAA1. In the present work, the CAA1 open reading frame from M. loti strain R7A was cloned, expressed, and biochemically characterized, and it was proven to be an active α-CA. The biochemical and physiological roles of the CAA1 gene in free-living and symbiotic rhizobia were examined by using an M. loti R7A disruption mutant strain. Our analysis revealed that CAA1 is expressed in both nitrogen-fixing bacteroids and free-living bacteria during growth in batch cultures, where gene expression was induced by increased medium pH. L. japonicus plants inoculated with the CAA1 mutant strain showed no differences in top-plant traits and nutritional status but consistently formed a higher number of nodules exhibiting higher fresh weight, N content, nitrogenase activity, and δ13C abundance. Based on these results, we propose that although CAA1 is not essential for nodule development and symbiotic nitrogen fixation, it may participate in an auxiliary mechanism that buffers the bacteroid periplasm, creating an environment favorable for NH3 protonation, thus facilitating its diffusion and transport to the plant. In addition, changes in the nodule δ13C abundance suggest the recycling of at least part of the HCO3− produced by CAA1. PMID:19218391

  11. Characterization of a Mesorhizobium loti alpha-type carbonic anhydrase and its role in symbiotic nitrogen fixation.

    Science.gov (United States)

    Kalloniati, Chrysanthi; Tsikou, Daniela; Lampiri, Vasiliki; Fotelli, Mariangela N; Rennenberg, Heinz; Chatzipavlidis, Iordanis; Fasseas, Costas; Katinakis, Panagiotis; Flemetakis, Emmanouil

    2009-04-01

    Carbonic anhydrase (CA) (EC 4.2.1.1) is a widespread enzyme catalyzing the reversible hydration of CO(2) to bicarbonate, a reaction that participates in many biochemical and physiological processes. Mesorhizobium loti, the microsymbiont of the model legume Lotus japonicus, possesses on the symbiosis island a gene (msi040) encoding an alpha-type CA homologue, annotated as CAA1. In the present work, the CAA1 open reading frame from M. loti strain R7A was cloned, expressed, and biochemically characterized, and it was proven to be an active alpha-CA. The biochemical and physiological roles of the CAA1 gene in free-living and symbiotic rhizobia were examined by using an M. loti R7A disruption mutant strain. Our analysis revealed that CAA1 is expressed in both nitrogen-fixing bacteroids and free-living bacteria during growth in batch cultures, where gene expression was induced by increased medium pH. L. japonicus plants inoculated with the CAA1 mutant strain showed no differences in top-plant traits and nutritional status but consistently formed a higher number of nodules exhibiting higher fresh weight, N content, nitrogenase activity, and delta(13)C abundance. Based on these results, we propose that although CAA1 is not essential for nodule development and symbiotic nitrogen fixation, it may participate in an auxiliary mechanism that buffers the bacteroid periplasm, creating an environment favorable for NH(3) protonation, thus facilitating its diffusion and transport to the plant. In addition, changes in the nodule delta(13)C abundance suggest the recycling of at least part of the HCO(3)(-) produced by CAA1.

  12. Monitoring of microbial community structure and succession in the biohydrogen production reactor by denaturing gradient gel electrophoresis (DGGE).

    Science.gov (United States)

    Xing, Defeng; Ren, Nanqi; Gong, Manli; Li, Jianzheng; Li, Qiubo

    2005-04-01

    To study the structure of microbial communities in the biological hydrogen production reactor and determine the ecological function of hydrogen producing bacteria, anaerobic sludge was obtained from the continuous stirred tank reactor (CSTR) in different periods of time, and the diversity and dynamics of microbial communities were investigated by denaturing gradient gel electrophoresis (DGGE). The results of DGGE demonstrated that an obvious shift of microbial population happened from the beginning of star-up to the 28th day, and the ethanol type fermentation was established. After 28 days the structure of microbial community became stable, and the climax community was formed. Comparative analysis of 16S rDNA sequences from reamplifying and sequencing the prominent bands indicated that the dominant population belonged to low G+C Gram-positive bacteria (Clostridium sp. and Ethanologenbacterium sp.), beta-proteobacteria (Acidovorax sp.), gamma-proteobacteria (Kluyvera sp.), Bacteroides (uncultured bacterium SJA-168), and Spirochaetes (uncultured eubacterium E1-K13), respectively. The hydrogen production rate increased obviously with the increase of Ethanologenbacterium sp., Clostridium sp. and uncultured Spirochaetes after 21 days, meanwhile the succession of ethanol type fermentation was formed. Throughout the succession the microbial diversity increased however it decreased after 21 days. Some types of Clostridium sp. Acidovorax sp., Kluyvera sp., and Bacteroides were dominant populations during all periods of time. These special populations were essential for the construction of climax community. Hydrogen production efficiency was dependent on both hydrogen producing bacteria and other populations. It implied that the co-metabolism of microbial community played a great role of biohydrogen production in the reactors.

  13. Xylan utilization in human gut commensal bacteria is orchestrated by unique modular organization of polysaccharide-degrading enzymes

    KAUST Repository

    Zhang, Meiling

    2014-08-18

    Enzymes that degrade dietary and host-derived glycans represent the most abundant functional activities encoded by genes unique to the human gut microbiome. However, the biochemical activities of a vast majority of the glycan-degrading enzymes are poorly understood. Here, we use transcriptome sequencing to understand the diversity of genes expressed by the human gut bacteria Bacteroides intestinalis and Bacteroides ovatus grown in monoculture with the abundant dietary polysaccharide xylan. The most highly induced carbohydrate active genes encode a unique glycoside hydrolase (GH) family 10 endoxylanase (BiXyn10A or BACINT-04215 and BACOVA-04390) that is highly conserved in the Bacteroidetes xylan utilization system. The BiXyn10A modular architecture consists of a GH10 catalytic module disrupted by a 250 amino acid sequence of unknown function. Biochemical analysis of BiXyn10A demonstrated that such insertion sequences encode a new family of carbohydrate-binding modules (CBMs) that binds to xy-lose- configured oligosaccharide/polysaccharide ligands, the substrate of the BiXyn10A enzymatic activity. The crystal structures of CBM1 from BiXyn10A (1.8 Å), a cocomplex of BiXyn10A CBM1 with xylohexaose (1.14 Å), and the CBM fromits homolog in the Prevotella bryantii B 14 Xyn10C (1.68 Å) reveal an unanticipated mode for ligand binding. Aminimal enzyme mix, composed of the gene products of four of the most highly up-regulated genes during growth on wheat arabinoxylan, depolymerizes the polysaccharide into its component sugars. The combined biochemical and biophysical studies presented here provide a framework for understanding fiber metabolism by an important group within the commensal bacterial population known to influence human health.

  14. Role of commensal bacteria in chronic experimental colitis: lessons from the HLA-B27 transgenic rat.

    Science.gov (United States)

    Rath, Heiko C

    Rats on Lewis or Fischer background, transgenic for human HLA-B27 and beta(2)-microglobulin genes spontaneously develop colitis, gastritis, arthritis, dermatitis, orchitis, epididymitis, carditis, alopecia and nail changes. Disease susceptibility correlates with the gene copy number and is influenced by the genetic background. The pathomechanism in this model is still not completely understood. Cell transfer experiments indicate an essential role of HLA-B27 expression in bone marrow-derived cells. On Fischer background the onset of colitis occurs at 2 months of age, peaks at 3 months of age, and plateaus. Histologic findings include inflammatory cell infiltration, mostly limited to the mucosa, crypt hyperplasia, reduction of goblet cells, occasionally crypt abscesses and early ulcers. There is evidence that normal luminal bacteria play an essential role in initiating and perpetuating chronic colitis and gastritis in HLA-B27 transgenic rats: Transgenic rats raised under germ-free conditions do not develop gastrointestinal disease, whereas transgenic littermates exposed to specific pathogen-free bacteria develop colitis and gastritis within 2-4 weeks. Obligate anaerobic bacteria, especially Bacteroides spp., may play a predominant role since metronidazole prevents colitis and transgenic germ-free rats contaminated with a cocktail of six obligate and facultative anaerobic bacteria develop colitis and gastritis only in the presence of Bacteroides vulgatus. Luminal bacteria may also be involved in trafficking and homing of inflammatory cells into remote organs, since varying cecal bacterial composition does not only alter local inflammation but also influences gastritis. Lymphocyte transfer experiments indicate a specific response to luminal bacteria. In summary, this animal model is suitable for investigating the influence of normal luminal bacteria on the cellular immune mechanism in chronic intestinal inflammation.

  15. Molecular analysis of the gut microbiota of identical twins with Crohn's disease

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Janet; Dicksved, Johan; Halfvarson, Jonas; Rosenquist, Magnus; Jarnerot, Gunnar; Tysk, Curt; Apajalahti, Juha; Engstrand, Lars; Jansson, Janet K.

    2008-03-14

    Increasing evidence suggests that a combination of host genetics and the composition of the gut microbiota are important for development of Crohn's disease (CD). Our aim was to study identical twins with CD to determine microbial factors independently of host genetics. Fecal samples were studied from 10 monozygotic twin pairs with CD (discordant n=6, concordant n=4) and 8 healthy twin pairs. DNA was extracted, 16S rRNA genes were PCR amplified and T-RFLP fingerprints generated using general bacterial and Bacteroides group specific primers. The microbial communities were also profiled based on their % G+C contents. Bacteroides 16S rRNA genes were cloned and sequenced from a subset of the samples. The bacterial diversity in each sample and similarity indices between samples were estimated based on the T-RFLP data using a combination of statistical approaches. Healthy individuals had a significantly higher bacterial diversity compared to individuals with CD. The fecal microbial communities were more similar between healthy twins than between twins with CD, especially when these were discordant for the disease. The microbial community profiles of individuals with ileal CD were significantly different from healthy individuals and those with colonic CD. Also, CD individuals had a lower relative abundance of B. uniformis and higher relative abundances of B. ovatus and B. vulgatus. Our results suggest that genetics and/or environmental exposure during childhood in part determine the gut microbial composition. However, CD is associated with dramatic changes in the gut microbiota and this was particularly evident for individuals with ileal CD.

  16. Bases farmacomicrobiológicas del tratamiento antibiótico de las enfermedades periodontales y periimplatarias Farmacobiological concepts in the antibiotic treatment of the periodontal diseases

    Directory of Open Access Journals (Sweden)

    J. Liñares

    2003-12-01

    Full Text Available La enfermedad periodontal debe considerarse un proceso infeccioso bacteriano crónico. En su etiología, no hay una única especie bacteriana implicada, sino que podríamos considerarla como una infección polimicrobiana en la que estarían implicados diversos microorganismos. Las bacterias que se han asociado más directamente con la enfermedad periodontal son Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus y Treponema denticola. Los parámetros farmacodinámicos de los antibióticos son muy útiles a la hora de seleccionar pautas posológicas. El aumento de resistencias producido en muchos periodontopatógenos en los últimos años ha relegado a algunos antibióticos a un segundo plano. Entre la gran variedad de antibióticos utilizados, se han obtenido buenas respuestas terapéuticas con amoxicilina/ácido clavulánico, metronidazol, clindamicina, doxiciclina y las combinaciones de metronidazol más amoxicilina y metronidazol más amoxicili-na/ácido clavulánico.Periodontal disease must be considered a chronic bacterial infection. It does not appear to one single bacterial species that is uniquely involved. Rather, periodontal disease seems to be a polymicrobial infection involving several organisms. The bacteria most often associated with periodontal disease are Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus y Treponema denticola. Pharmacodynamics parameters are very useful to select dosing regimens. The increase in prevalence of resistance occurred in some periodontopathogens in the last years has pushed some antibiotics into the background. Positive responses have been reported with amoxicillin/clavulanate, metronidazole, clindamycin, doxycycline and the combination therapy metronidazole plus amoxicillin and metronidazole plus amoxicillin/clavulanate.

  17. Effects of the Dietary Protein and Carbohydrate Ratio on Gut Microbiomes in Dogs of Different Body Conditions

    Science.gov (United States)

    Lauber, Christian L.; Czarnecki-Maulden, Gail; Pan, Yuanlong; Hannah, Steven S.

    2017-01-01

    ABSTRACT Obesity has become a health epidemic in both humans and pets. A dysbiotic gut microbiota has been associated with obesity and other metabolic disorders. High-protein, low-carbohydrate (HPLC) diets have been recommended for body weight loss, but little is known about their effects on the canine gut microbiome. Sixty-three obese and lean Labrador retrievers and Beagles (mean age, 5.72 years) were fed a common baseline diet for 4 weeks in phase 1, followed by 4 weeks of a treatment diet, specifically, the HPLC diet (49.4% protein, 10.9% carbohydrate) or a low-protein, high-carbohydrate (LPHC) diet (25.5% protein, 38.8% carbohydrate) in phase 2. 16S rRNA gene profiling revealed that dietary protein and carbohydrate ratios have significant impacts on gut microbial compositions. This effect appeared to be more evident in obese dogs than in lean dogs but was independent of breed. Consumption of either diet increased the bacterial evenness, but not the richness, of the gut compared to that after consumption of the baseline diet. Macronutrient composition affected taxon abundances, mainly within the predominant phyla, Firmicutes and Bacteroidetes. The LPHC diet appeared to favor the growth of Bacteroides uniformis and Clostridium butyricum, while the HPLC diet increased the abundances of Clostridium hiranonis, Clostridium perfringens, and Ruminococcus gnavus and enriched microbial gene networks associated with weight maintenance. In addition, we observed a decrease in the Bacteroidetes to Firmicutes ratio and an increase in the Bacteroides to Prevotella ratio in the HPLC diet-fed dogs compared to these ratios in dogs fed other diets. Finally, analysis of the effect of diet on the predicted microbial gene network was performed using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). PMID:28119466

  18. Sulfate-reducing bacteria colonize pouches formed for ulcerative colitis but not for familial adenomatous polyposis.

    LENUS (Irish Health Repository)

    Duffy, M

    2012-02-03

    PURPOSE: Ileal pouch-anal anastomosis remains the "gold standard" in surgical treatment of ulcerative colitis and familial adenomatous polyposis. Pouchitis occurs mainly in patients with a background of ulcerative colitis, although the reasons for this are unknown. The aim of this study was to characterize differences in pouch bacterial populations between ulcerative colitis and familial adenomatous pouches. METHODS: After ethical approval was obtained, fresh stool samples were collected from patients with ulcerative colitis pouches (n = 10), familial adenomatous polyposis (n = 7) pouches, and ulcerative colitis ileostomies (n = 8). Quantitative measurements of aerobic and anaerobic bacteria were performed. RESULTS: Sulfate-reducing bacteria were isolated from 80 percent (n = 8) of ulcerative colitis pouches. Sulfate-reducing bacteria were absent from familial adenomatous polyposis pouches and also from ulcerative colitis ileostomy effluent. Pouch Lactobacilli, Bifidobacterium, Bacteroides sp, and Clostridium perfringens counts were increased relative to ileostomy counts in patients with ulcerative colitis. Total pouch enterococci and coliform counts were also increased relative to ileostomy levels. There were no significant quantitative or qualitative differences between pouch types when these bacteria were evaluated. CONCLUSIONS: Sulfate-reducing bacteria are exclusive to patients with a background of ulcerative colitis. Not all ulcerative colitis pouches harbor sulfate-reducing bacteria because two ulcerative colitis pouches in this study were free of the latter. They are not present in familial adenomatous polyposis pouches or in ileostomy effluent collected from patients with ulcerative colitis. Total bacterial counts increase in ulcerative colitis pouches after stoma closure. Levels of Lactobacilli, Bifidobacterium, Bacteroides sp, Clostridium perfringens, enterococci, and coliforms were similar in both pouch groups. Because sulfate-reducing bacteria are

  19. Disrupted intestinal microbiota and intestinal inflammation in children with cystic fibrosis and its restoration with Lactobacillus GG: a randomised clinical trial.

    Directory of Open Access Journals (Sweden)

    Eugenia Bruzzese

    Full Text Available BACKGROUND & AIMS: Intestinal inflammation is a hallmark of cystic fibrosis (CF. Administration of probiotics can reduce intestinal inflammation and the incidence of pulmonary exacerbations. We investigated the composition of intestinal microbiota in children with CF and analyzed its relationship with intestinal inflammation. We also investigated the microflora structure before and after Lactobacillus GG (LGG administration in children with CF with and without antibiotic treatment. METHODS: The intestinal microbiota were analyzed by denaturing gradient gel electrophoresis (DGGE, real-time polymerase chain reaction (RT-PCR, and fluorescence in situ hybridization (FISH. Intestinal inflammation was assessed by measuring fecal calprotectin (CLP and rectal nitric oxide (rNO production in children with CF as compared with healthy controls. We then carried out a small double-blind randomized clinical trial with LGG. RESULTS: Twenty-two children with CF children were enrolled in the study (median age, 7 years; range, 2-9 years. Fecal CLP and rNO levels were higher in children with CF than in healthy controls (184±146 µg/g vs. 52±46 µg/g; 18±15 vs. 2.6±1.2 µmol/L NO2 (-, respectively; P<0.01. Compared with healthy controls, children with CF had significantly different intestinal microbial core structures. The levels of Eubacterium rectale, Bacteroides uniformis, Bacteroides vulgatus, Bifidobacterium adolescentis, Bifidobacterium catenulatum, and Faecalibacterium prausnitzii were reduced in children with CF. A similar but more extreme pattern was observed in children with CF who were taking antibiotics. LGG administration reduced fecal CLP and partially restored intestinal microbiota. There was a significant correlation between reduced microbial richness and intestinal inflammation. CONCLUSIONS: CF causes qualitative and quantitative changes in intestinal microbiota, which may represent a novel therapeutic target in the treatment of CF

  20. Anaerobic Bacteremia: Impact of Inappropriate Therapy on Mortality

    Science.gov (United States)

    Lee, Yangsoon; Park, Yongjung; Kim, Myungsook; Choi, Jun Yong; Yong, Dongeun; Jeong, Seok Hoon

    2016-01-01

    Background Investigation on incidence and mortality of anaerobic bacteremia (AB) is clinically relevant in spite of its infrequent occurrence and not often explored, which report varies according to period and institutions. Therefore, it is necessary to analyze the incidence and risk factors related to mortality and assess clinical outcomes of AB in current aspect. Materials and Methods Characteristics of AB patients and anaerobic bacteria from blood culture at a university hospital in 2012 were reviewed retrospectively. The correlation between risk factors and 28-day patient mortality was analyzed. Results A total of 70 non-duplicated anaerobic bacteria were isolated from blood of 70 bacteremia patients in 2012. The history of cardiovascular disease as host's risk factor was statistically significant (P = 0.0344) in univariate and multivariate analysis. Although the inappropriate therapy was not statistically significant in univariate and multivariate analysis, the survival rate of bacteremia was significantly worse in patients who had inappropriate therapy compared with those underwent appropriate therapy (hazard ratio, 5.4; 95% confidence interval, 1.7–6.9; P = 0.004). The most frequently isolated organism was Bacteroides fragilis (32 isolates, 46%), followed by Bacteroides thetaiotaomicron (10, 14%), and non-perfringens Clostridium (7, 10%). Conclusion The incidence of AB in 2012 was 2.3% (number of AB patients per 100 positive blood culture patients) and the mortality rate in patients with clinically significant AB was 21.4%. In addition, AB was frequently noted in patients having malignancy and the survival rate of AB was significantly worse in patients who received inappropriate therapy compared with those underwent appropriate therapy. PMID:27433379

  1. Monitoring of microbial community structure and succession in the biohydrogen production reactor by denaturing gradient gel electrophoresis (DGGE)

    Institute of Scientific and Technical Information of China (English)

    XING; Defeng; REN; Nanqi; GONG; Manli; LI; Jianzheng; LI; Q

    2005-01-01

    To study the structure of microbial communities in the biological hydrogen production reactor and determine the ecological function of hydrogen producing bacteria, anaerobic sludge was obtained from the continuous stirred tank reactor (CSTR) in different periods of time, and the diversity and dynamics of microbial communities were investigated by denaturing gradient gel electrophoresis (DGGE). The results of DGGE demonstrated that an obvious shift of microbial population happened from the beginning of star-up to the 28th day, and the ethanol type fermentation was established. After 28 days the structure of microbial community became stable, and the climax community was formed. Comparative analysis of 16S rDNA sequences from reamplifying and sequencing the prominent bands indicated that the dominant population belonged to low G+C Gram-positive bacteria (Clostridium sp. And Ethanologenbacterium sp.), β- proteobacteria (Acidovorax sp.), γ-proteobacteria (Kluyvera sp.), Bacteroides (uncultured bacterium SJA-168), and Spirochaetes (uncultured eubacterium E1-K13), respectively. The hydrogen production rate increased obviously with the increase of Ethanologenbacterium sp., Clostridium sp. And uncultured Spirochaetes after 21 days, meanwhile the succession of ethanol type fermentation was formed. Throughout the succession the microbial diversity increased however it decreased after 21 days. Some types of Clostridium sp. Acidovorax sp., Kluyvera sp., and Bacteroides were dominant populations during all periods of time. These special populations were essential for the construction of climax community. Hydrogen production efficiency was dependent on both hydrogen producing bacteria and other populations. It implied that the co-metabolism of microbial community played a great role of biohydrogen production in the reactors.

  2. Genetic analysis of the Rhizobium meliloti bacA gene: functional interchangeability with the Escherichia coli sbmA gene and phenotypes of mutants.

    Science.gov (United States)

    Ichige, A; Walker, G C

    1997-01-01

    The Rhizobium meliloti bacA gene encodes a function that is essential for bacterial differentiation into bacteroids within plant cells in the symbiosis between R. meliloti and alfalfa. An Escherichia coli homolog of BacA, SbmA, is implicated in the uptake of microcin B17, microcin J25 (formerly microcin 25), and bleomycin. When expressed in E. coli with the lacZ promoter, the R. meliloti bacA gene was found to suppress all the known defects of E. coli sbmA mutants, namely, increased resistance to microcin B17, microcin J25, and bleomycin, demonstrating the functional similarity between the two proteins. The R. meliloti bacA386::Tn(pho)A mutant, as well as a newly constructed bacA deletion mutant, was found to show increased resistance to bleomycin. However, it also showed increased resistance to certain aminoglycosides and increased sensitivity to ethanol and detergents, suggesting that the loss of bacA function causes some defect in membrane integrity. The E. coli sbmA gene suppressed all these bacA mutant phenotypes as well as the Fix- phenotype when placed under control of the bacA promoter. Taken together, these results strongly suggest that the BacA and SbmA proteins are functionally similar and thus provide support for our previous hypothesis that BacA may be required for uptake of some compound that plays an important role in bacteroid development. However, the additional phenotypes of bacA mutants identified in this study suggest the alternative possibility that BacA may be needed for membrane integrity, which is likely to be critically important during the early stages of bacterial differentiation within plant cells.

  3. Identifying keystone species in the human gut microbiome from metagenomic timeseries using sparse linear regression.

    Directory of Open Access Journals (Sweden)

    Charles K Fisher

    Full Text Available Human associated microbial communities exert tremendous influence over human health and disease. With modern metagenomic sequencing methods it is now possible to follow the relative abundance of microbes in a community over time. These microbial communities exhibit rich ecological dynamics and an important goal of microbial ecology is to infer the ecological interactions between species directly from sequence data. Any algorithm for inferring ecological interactions must overcome three major obstacles: 1 a correlation between the abundances of two species does not imply that those species are interacting, 2 the sum constraint on the relative abundances obtained from metagenomic studies makes it difficult to infer the parameters in timeseries models, and 3 errors due to experimental uncertainty, or mis-assignment of sequencing reads into operational taxonomic units, bias inferences of species interactions due to a statistical problem called "errors-in-variables". Here we introduce an approach, Learning Interactions from MIcrobial Time Series (LIMITS, that overcomes these obstacles. LIMITS uses sparse linear regression with boostrap aggregation to infer a discrete-time Lotka-Volterra model for microbial dynamics. We tested LIMITS on synthetic data and showed that it could reliably infer the topology of the inter-species ecological interactions. We then used LIMITS to characterize the species interactions in the gut microbiomes of two individuals and found that the interaction networks varied significantly between individuals. Furthermore, we found that the interaction networks of the two individuals are dominated by distinct "keystone species", Bacteroides fragilis and Bacteroided stercosis, that have a disproportionate influence on the structure of the gut microbiome even though they are only found in moderate abundance. Based on our results, we hypothesize that the abundances of certain keystone species may be responsible for individuality in

  4. Microbial community mapping in intestinal tract of broiler chicken.

    Science.gov (United States)

    Xiao, Yingping; Xiang, Yun; Zhou, Weidong; Chen, Jinggang; Li, Kaifeng; Yang, Hua

    2016-10-06

    Domestic chickens are valuable sources of protein associated with producing meat and eggs for humans. The gastrointestinal tract (GIT) houses a large microbial community, and these microbiota play an important role in growth and health of chickens, contributing to the enhancement of nutrient absorption and improvement of the birds' immune systems. To improve our understanding of the chicken intestinal microbial composition, microbiota inhabiting 5 different intestinal locations (duodenum, jejunum, ileum, cecum, and colon) of 42-day-old broiler chickens were detected based on 16S rRNA gene sequence analysis. As a result, 1,502,554 sequences were clustered into 796 operational taxonomic units (OTUs) at the 97% sequence similarity value and identified into 15 phyla and 288 genera. Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, and Cyanobacteria were the major microbial groups and Firmicutes was the dominant phylum in duodenum, jejunum, ileum and colon accounting for > 60% of sequences, while Bacteroidetes was the dominant phylum in cecum (>50% of sequences), but little in the other four gut sections. At the genus level, the major microbial genera across all gut sections were Lactobacillus, Enterococcus, Bacteroides, and Corynebacterium. Lactobacillus was the predominant genus in duodenum, jejunum, and ileum (>35%), but was rarely present in cecum, and Bacteroides was the most dominant group in cecum (about 40%), but rarely present in the other 4 intestinal sections. Differences of microbial composition between the 5 intestinal locations might be a cause and consequence of gut functional differences and may also reflect host selection mediated by innate or adaptive immune responses. All these results could offer some information for the future study on the relationship between intestinal microbiota and broiler chicken growth performance as well as health.

  5. Inulin and fructo-oligosaccharides have divergent effects on colitis and commensal microbiota in HLA-B27 transgenic rats.

    Science.gov (United States)

    Koleva, Petya T; Valcheva, Rosica S; Sun, Xu; Gänzle, Michael G; Dieleman, Levinus A

    2012-11-14

    Modulation of intestinal microbiota by non-digestible carbohydrates may reduce inflammation in inflammatory bowel disease (IBD). The aim of the present study was to assess the effects of inulin and fructo-oligosaccharides (FOS) on intestinal microbiota and colitis in HLA-B27 transgenic rats, a well-validated rodent model for IBD. In this study, 4-week-old rats were fed 8 g/kg body weight inulin or FOS for 12 weeks, or not. Faeces were collected at 4 and 16 weeks of age; and caecal samples were collected at necropsy. The effects of inulin and FOS on chronic intestinal inflammation were assessed using a gross gut score, histology score and levels of mucosal IL-1β. Intestinal microbiota were characterised by quantitative PCR and denaturing gradient gel electrophoresis. Colitis was significantly reduced in all FOS-fed rats compared to the control diet, whereas inulin decreased chronic intestinal inflammation in only half the number of animals. Quantitative analysis of caecal microbiota demonstrated that inulin increased the numbers of total bacteria and the Bacteroides-Prevotella-Porphyromonas group, FOS increased bifidobacteria, and both fructans decreased Clostridium cluster XI. In the faecal samples, both inulin and FOS decreased total bacteria, Bacteroides-Prevotella-Porphyromonas group, and Clostridium clusters XI and XIVa. FOS increased Bifidobacterium spp., and mediated a decrease of gene copies of Enterobacteriaceae and Clostridium difficile toxin B in faeces. SCFA concentrations in the faecal and caecal samples were unaffected by the diets. In conclusion, FOS increased the abundance of Bifidobacterium spp., whereas both fructans reduced Clostridium cluster XI and C. difficile toxin gene expression, correlating with a reduction of chronic intestinal inflammation.

  6. Propionibacterium acidipropionici CRL1198 influences the production of acids and the growth of bacterial genera stimulated by inulin in a murine model of cecal slurries.

    Science.gov (United States)

    Lorenzo-Pisarello, M J; Gultemirian, M L; Nieto-Peñalver, C; Perez Chaia, A

    2010-08-01

    Different attempts have been made to improve the health status of humans and animals by increasing the intestinal production of short-chain fatty acids (SCFA) derived from non-digestible carbohydrates fermentation. In this paper we investigate the in vitro production of short-chain fatty acids (SCFA) after addition of inulin, propionibacteria or a combination of both in an experimental model of mice cecal slurries. The development of bacterial genera which are usually stimulated by inulin addition was also investigated. According to our experimental data, acetic acid and butyric acids concentrations increased after incubation in slurries that had no supplements. By contrast, butyric acid concentrations remained in the basal value when supplements were used. Fermentation of only inulin did not increase the concentration of total SCFA. Propionibacterium acidipropionici CRL1198 improved the production of propionic acid in cecal slurries when it was added alone, but the effect was more noticeable in the combination with inulin. A modulation of the global fermentative activity of the cecal microbiota was evidenced by the increase on the ratio propionic acid/SCFA in supplementations with propionibacteria. Statistical analysis of data demonstrated that samples from homogenates with propionibacteria alone or combined with inulin belong to the same cluster. The presence of propionibacteria limited the growth of Bacteroides fragilis and Clostridium hystoliticum groups in slurries with and without inulin. The growth of Bifidobacterium was not modified and the stimulating effect of inulin on lactobacilli disappeared in the presence of propionibacteria. In conclusion, dairy propionibacteria are potential candidates to develop new functional foods helpful to ensure the intestinal production of SCFA during inulin supplementation and to control the overgrowth of bacteria belonging to Bacteroides and Clostridium genera.

  7. A novel sampling method for the investigation of gut microbiota

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: In order to characterize the qualitative and quantitative microorganisms in different sites of the lower digestive tract (LDT) in healthy volunteers, a specific technique was developed for collecting mucous of the distal ileum, colon and rectum.METHODS: A polyethylene tube was designed to go through the colonoscope channel with a No. 8 French tube. In order to avoid internal contamination, the distal extremity was protected with a membrane of microfilm after being sterilized in ethilene oxid. To facilitate the aspiration of a precise volume, its interior was coated with silicone. One hundred microlliter (0.1 mL) sample of mucous was collected and transferred into an Eppenddorff tube containing nine hundred microlliter (0.9 mL) of VMGA-3 (viable medium of Goteborg). This procedure was repeated at each site of the LDT with a new sterilized catheter.RESULTS: All sites revealed the "non pathogenic"anaerobic bacteria Veillonella sp (average 105 colony forming units/mL-CFU/mL), allowing to conclude an environment of low oxidation-reduction potential (redox)in the LDT. It was also characterized the presence of Klebisiella sp with significant statistical predominance (SSP) in the ileum. Enterobacter sp was found with SSP in the sigmoid colon, BacteroideS sp non-pigmented (npg)and E. coli with SSP in the sigmoid colon and rectum,Enterococcus sp and Lactobacillus sp with SSP in the rectum, all in a mean concentration of 105 CFU/mL.CONCLUSION: This procedure is feasible and efficient and can point out a similar distribution of the aerobic and anaerobic bacteria with the presence of biological markers of normal microbiota in the LDT.

  8. Progreso en el conocimiento de la microbiota intestinal humana

    Directory of Open Access Journals (Sweden)

    Virginia Robles-Alonso

    2013-06-01

    Full Text Available La aparición de nuevas técnicas de secuenciación así como el desarrollo de herramientas bioinformáticas han permitido no sólo describir la composición de la comunidad bacteriana que habita el tracto gastrointestinal, sino también las funciones metabólicas de las que proveen al huésped. La mayoría de los miembros de esta amplia comunidad bacteriana pertenecen a Dominio Bacteria, aunque encontramos también Archaea y formas eucariotas y virus. Únicamente entre 7 y 9 de las 55 Phyla del Dominio Bacteria conocidos están presentes en flora fecal humana. Su mayoría pertenecen además a las Divisiones Bacteroidetes and Firmicutes, encontrando también Proteobacteria, Actinobacteria, Fusobacteria y Verrucomicrobia. Bacteroides, Faecalibacterium y Bifidobacterium son los Géneros más abundantes aunque su abundancia relativa es muy variable entre individuos. El análisis metagenómico de la flora intestinal ha permitido describir una colección de 5 millones de genes microbianos que codifican para aproximadamente 20.000 funciones biológicas relacionadas con la vida de las bacterias. El ecosistema intestinal humano puede clasificarse en torno a tres grupos de acuerdo a la abundancia relativa de tres Géneros: Bacteroides (enterotipo 1, Prevotella (enterotipo 2 y Ruminococcus (enterotype 3. Estos grupos han sido denominados "enterotipos" y su descripción sugiere que las variaciones entre individuos están estratificadas. Una vez descrita la composición bacteriana sería interesante establecer la relación entre la alteración de equilibrios ecológicos con estados de enfermedad que puedan desembocar en una novedosa vía terapéutica.

  9. Avaliação das atividades antibacteriana, tripanocida e citotóxica do extrato hidroalcóolico das raízes de Tradescantia sillamontana Matuda (Veludo Branco (Commelinaceae

    Directory of Open Access Journals (Sweden)

    E.B.B. ESTEVAM

    Full Text Available RESUMO O objetivo deste estudo foi avaliar o efeito antibacteriano e tripanocida in vitro do extrato hidroalcóolico das raízes de Tradescantia sillamontana Matuda (Commelinaceae, conhecida popularmente como veludo branco. Foi avaliada a atividade antibacteriana in vitro frente às bactérias Streptococcus mitis (CIM = 100 µg/mL; CMB = 150 µg/mL, Streptococcus mutans (CIM = 200 µg/mL; CMB = 220 µg/mL, Streptococcus sanguinis (CIM = 400 µg/mL; CMB = 425 µg/mL, Streptococcus sobrinus (CIM = 400 µg/mL; CMB = 420 µg/mL e Bacteroides fragilis (CIM = 400 µg/mL; CMB = 430 µg/mL pelo método de diluição em caldo. Os protozoários da família tripanossomatídeo causam doenças tropicais que costumam ser negligenciadas que costumam ser como a tripanossomíase, para a qual estão disponíveis poucos medicamentos. Neste contexto, o extrato hidroalcóolico das raízes de T. sillamontana também foi avaliado frente às formas tripomastigotas da cepa Y de Trypanosoma cruzi, com promissora atividade frente a este protozoário (IC50 = 2,4 µg/mL. Quando avaliada a atividade citotóxica frente a fibroblastos da linhagem LLCMK2, o extrato apresentou moderada citotoxicidade (CC50 = 480,37 µg/mL. Os resultados ora apresentados para o extrato hidroalcóolico das raízes de Tradescantia sillamontana Matuda demonstraram promissoras atividades antibacteriana e tripanocida, sendo uma fonte alternativa de produtos naturais com atividades contra T. cruzi e algumas bactérias do gênero Streptococcus e Bacteroides.

  10. Fish oil enhances recovery of intestinal microbiota and epithelial integrity in chronic rejection of intestinal transplant.

    Directory of Open Access Journals (Sweden)

    Qiurong Li

    Full Text Available BACKGROUND: The intestinal chronic rejection (CR is the major limitation to long-term survival of transplanted organs. This study aimed to investigate the interaction between intestinal microbiota and epithelial integrity in chronic rejection of intestinal transplantation, and to find out whether fish oil enhances recovery of intestinal microbiota and epithelial integrity. METHODS/PRINCIPAL FINDINGS: The luminal and mucosal microbiota composition of CR rats were characterized by DGGE analysis at 190 days after intestinal transplant. The specific bacterial species were determined by sequence analysis. Furthermore, changes in the localization of intestinal TJ proteins were examined by immunofluorescent staining. PCR-DGGE analysis revealed that gut microbiota in CR rats had a shift towards Escherichia coli, Bacteroides spp and Clostridium spp and a decrease in the abundance of Lactobacillales bacteria in the intestines. Fish oil supplementation could enhance the recovery of gut microbiota, showing a significant decrease of gut bacterial proportions of E. coli and Bacteroides spp and an increase of Lactobacillales spp. In addition, CR rats showed pronounced alteration of tight junction, depicted by marked changes in epithelial cell ultrastructure and redistribution of occuldin and claudins as well as disruption in TJ barrier function. Fish oil administration ameliorated disruption of epithelial integrity in CR, which was associated with an improvement of the mucosal structure leading to improved tight junctions. CONCLUSIONS/SIGNIFICANCE: Our study have presented novel evidence that fish oil is involved in the maintenance of epithelial TJ integrity and recovery of gut microbiota, which may have therapeutic potential against CR in intestinal transplantation.

  11. Gut Dysbiosis in Patients with Anorexia Nervosa.

    Science.gov (United States)

    Morita, Chihiro; Tsuji, Hirokazu; Hata, Tomokazu; Gondo, Motoharu; Takakura, Shu; Kawai, Keisuke; Yoshihara, Kazufumi; Ogata, Kiyohito; Nomoto, Koji; Miyazaki, Kouji; Sudo, Nobuyuki

    2015-01-01

    Anorexia nervosa (AN) is a psychological illness with devastating physical consequences; however, its pathophysiological mechanism remains unclear. Because numerous reports have indicated the importance of gut microbiota in the regulation of weight gain, it is reasonable to speculate that AN patients might have a microbial imbalance, i.e. dysbiosis, in their gut. In this study, we compared the fecal microbiota of female patients with AN (n = 25), including restrictive (ANR, n = 14) and binge-eating (ANBP, n = 11) subtypes, with those of age-matched healthy female controls (n = 21) using the Yakult Intestinal Flora-SCAN based on 16S or 23S rRNA-targeted RT-quantitative PCR technology. AN patients had significantly lower amounts of total bacteria and obligate anaerobes including those from the Clostridium coccoides group, Clostridium leptum subgroup, and Bacteroides fragilis group than the age-matched healthy women. Lower numbers of Streptococcus were also found in the AN group than in the control group. In the analysis based on AN subtypes, the counts of the Bacteroides fragilis group in the ANR and ANBP groups and the counts of the Clostridium coccoides group in the ANR group were significantly lower than those in the control group. The detection rate of the Lactobacillus plantarum subgroup was significantly lower in the AN group than in the control group. The AN group had significantly lower acetic and propionic acid concentrations in the feces than the control group. Moreover, the subtype analysis showed that the fecal concentrations of acetic acid were lower in the ANR group than in the control group. Principal component analysis confirmed a clear difference in the bacterial components between the AN patients and healthy women. Collectively, these results clearly indicate the existence of dysbiosis in the gut of AN patients.

  12. Gut Dysbiosis in Patients with Anorexia Nervosa.

    Directory of Open Access Journals (Sweden)

    Chihiro Morita

    Full Text Available Anorexia nervosa (AN is a psychological illness with devastating physical consequences; however, its pathophysiological mechanism remains unclear. Because numerous reports have indicated the importance of gut microbiota in the regulation of weight gain, it is reasonable to speculate that AN patients might have a microbial imbalance, i.e. dysbiosis, in their gut. In this study, we compared the fecal microbiota of female patients with AN (n = 25, including restrictive (ANR, n = 14 and binge-eating (ANBP, n = 11 subtypes, with those of age-matched healthy female controls (n = 21 using the Yakult Intestinal Flora-SCAN based on 16S or 23S rRNA-targeted RT-quantitative PCR technology. AN patients had significantly lower amounts of total bacteria and obligate anaerobes including those from the Clostridium coccoides group, Clostridium leptum subgroup, and Bacteroides fragilis group than the age-matched healthy women. Lower numbers of Streptococcus were also found in the AN group than in the control group. In the analysis based on AN subtypes, the counts of the Bacteroides fragilis group in the ANR and ANBP groups and the counts of the Clostridium coccoides group in the ANR group were significantly lower than those in the control group. The detection rate of the Lactobacillus plantarum subgroup was significantly lower in the AN group than in the control group. The AN group had significantly lower acetic and propionic acid concentrations in the feces than the control group. Moreover, the subtype analysis showed that the fecal concentrations of acetic acid were lower in the ANR group than in the control group. Principal component analysis confirmed a clear difference in the bacterial components between the AN patients and healthy women. Collectively, these results clearly indicate the existence of dysbiosis in the gut of AN patients.

  13. Application of empirical predictive modeling using conventional and alternative fecal indicator bacteria in eastern North Carolina waters

    Science.gov (United States)

    Gonzalez, Raul; Conn, Kathleen E.; Crosswell, Joey; Noble, Rachel

    2012-01-01

    Coastal and estuarine waters are the site of intense anthropogenic influence with concomitant use for recreation and seafood harvesting. Therefore, coastal and estuarine water quality has a direct impact on human health. In eastern North Carolina (NC) there are over 240 recreational and 1025 shellfish harvesting water quality monitoring sites that are regularly assessed. Because of the large number of sites, sampling frequency is often only on a weekly basis. This frequency, along with an 18–24 h incubation time for fecal indicator bacteria (FIB) enumeration via culture-based methods, reduces the efficiency of the public notification process. In states like NC where beach monitoring resources are limited but historical data are plentiful, predictive models may offer an improvement for monitoring and notification by providing real-time FIB estimates. In this study, water samples were collected during 12 dry (n = 88) and 13 wet (n = 66) weather events at up to 10 sites. Statistical predictive models for Escherichiacoli (EC), enterococci (ENT), and members of the Bacteroidales group were created and subsequently validated. Our results showed that models for EC and ENT (adjusted R2 were 0.61 and 0.64, respectively) incorporated a range of antecedent rainfall, climate, and environmental variables. The most important variables for EC and ENT models were 5-day antecedent rainfall, dissolved oxygen, and salinity. These models successfully predicted FIB levels over a wide range of conditions with a 3% (EC model) and 9% (ENT model) overall error rate for recreational threshold values and a 0% (EC model) overall error rate for shellfish threshold values. Though modeling of members of the Bacteroidales group had less predictive ability (adjusted R2 were 0.56 and 0.53 for fecal Bacteroides spp. and human Bacteroides spp., respectively), the modeling approach and testing provided information on Bacteroidales ecology. This is the first example of a set of successful statistical

  14. Biochemical and functional characterization of phosphoserine aminotransferase from Entamoeba histolytica, which possesses both phosphorylated and non-phosphorylated serine metabolic pathways.

    Science.gov (United States)

    Ali, Vahab; Nozaki, Tomoyoshi

    2006-01-01

    The enteric protozoan parasite Entamoeba histolytica is a unicellular eukaryote that possesses both phosphorylated and non-phosphorylated serine metabolic pathways. In the present study, we described enzymological and functional characterization of phosphoserine aminotransferase (PSAT) from E. histolytica. E. histolytica PSAT (EhPSAT) showed maximum activity for the forward reaction at basic pH, dissimilar to mammalian PSAT, which showed sharp neutral optimum pH. EhPSAT activity was significantly inhibited by substrate analogs, O-phospho-d-serine, O-phospho-l-threonine, and O-acetylserine, suggesting possible regulation of the amoebic PSAT by these metabolic intermediates. Fractionation of the whole parasite lysate and rEhPSAT by anion exchange chromatography verified that EhPSAT represents a dominant PSAT activity. EhPSAT showed a close kinship to PSAT from bacteroides based on amino acid alignment and phylogenetic analyses, suggesting that E. histolytica gained this gene from bacteroides by lateral gene transfer. Comparisons of kinetic properties of recombinant PSAT from E. histolytica and Arabidopsis thaliana showed that EhPSAT possesses significantly higher affinity toward glutamate than the A. thaliana counterpart, which may be explained by significant differences in the isoelectric point and the substitution of arginine, which is involved the binding to the gamma-carboxylate moiety of glutamate, in Escherichia coli PSAT, to serine or threonine in E. histolytica or A. thaliana PSAT, respectively. Heterologous expression of EhPSAT successfully rescued growth defect of a serine-auxotrophic E. coli strain KL282, where serC was deleted, confirming its in vivo role in serine biosynthesis. Together with our previous demonstration of phosphoglycerate dehydrogenase, the present study reinforces physiological significance of the phosphorylated pathway in amoeba.

  15. Phylogenetic diversity of dissimilatory ferric iron reducers in paddy soil of Hunan, South China

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xin-Jun [State Key Lab. of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, BJ (China); Graduate Univ., Chinese Academy of Sciences, BJ (China); Yang Jing; Chen Xue-Ping; Sun Guo-Xin [State Key Lab. of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, BJ (China); Zhu Yong-Guan [State Key Lab. of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, BJ (China); Key Lab. of Urban Environment and Health, Inst. of Urban Environment, Chinese Academy of Sciences, Xiamen (China)

    2009-12-15

    Purpose: Dissimilatory iron-reducing bacteria have been described by both culture-dependent and -independent methods in various environments, including freshwater, marine sediments, natural wetlands, and contaminated aquifers. However, little is known about iron-reducing microbial communities in paddy soils. The goal of this study was to characterize iron-reducing microbial communities in paddy soil. Moreover, the effect of dissolved and solid-phase iron (III) species on the iron-reducing microbial communities was also investigated by enrichment cultures. Methods: Ferric citrate and ferrihydrite were used respectively to set up enrichment cultures of dissimilatory ironreducing microorganisms using 1% inoculum of soil samples, and the iron reduction was measured. Moreover, bacterial DNA was extracted and 16S rRNA genes were PCR-amplified, and subsequently analyzed by the clone library and terminal restriction fragment length polymorphism (T-RFLP). Results: Phylogenetic analysis of 16S rRNA gene sequences extracted from the enrichment cultures revealed that Bradyrhizobium, Bacteroides, Clostridium and Ralstonia species were the dominant bacteria in the ferric citrate enrichment. However, members of the genera Clostridium, Bacteroides, and Geobacter were the dominant micro-organisms in the ferrihydrite enrichment. Analysis of enrichment cultures by T-RFLP strongly supported the cloning and sequencing results. Conclusions: The present study demonstrated that dissimilatory iron-reducing consortia in As-contaminated paddy soil are phylogenetically diverse. Moreover, iron (III) sources as a key factor have a strong effect on the iron (III)-reducing microbial community structure and relative abundance in the enrichments. In addition, Geobacter species are selectively enriched by ferrihydrite enrichment cultures. (orig.)

  16. Significant differences in fecal microbiota are associated with various stages of glucose tolerance in African American male veterans.

    Science.gov (United States)

    Ciubotaru, Irina; Green, Stefan J; Kukreja, Subhash; Barengolts, Elena

    2015-11-01

    The importance of gut microbiota in pathogenesis of diabetes remains unknown. This study investigated the relationship between microbiota and metabolic markers in African American men (AAM) with prediabetes and hypovitaminosis D. The study was ancillary to a randomized trial of vitamin D supplementation with weekly ergocalciferol (50,000 IU) conducted in AAM veterans over 12 months (D Intervention in Veterans Affairs). Glycemic groups (Gr) were characterized based on changes in oral glucose tolerance between baseline and exit. Subjects with stable normal glucose tolerance were assigned to Gr-1 and those with stable prediabetes (impaired glucose tolerance and impaired fasting glucose) to Gr-2. Microbiota composition was analyzed in stool collected at the exit (n = 115) and compared between Gr-1 and Gr-2, as well as between the lowest and highest quartiles of dietary intake of energy and fat, hemoglobin A1c, and serum 25-hydroxyvitamin D (25[OH]D) level. Differences between Gr-1 and Gr-2 included the Bacteroidetes/Firmicutes and Bacteroidales/Clostridia ratios and differences in genera such as Ruminococcus and Dialister. Changes in specific taxa associated with the lowest and highest quartiles of 25(OH)D (eg, Ruminococcus, Roseburia, Blautia, Dorea) were clearly distinct from those of dietary intake (eg, Bacteroides, Bacteroides/Prevotella ratio) or A1c (eg, Faecalibacterium, Catenibacterium, Streptococcus). These findings suggest a novel interaction between microbiota and vitamin D and a role for microbiota in early stages of diabetes development. Although results suggest that specific taxa are associated with glycemic stability over time, a causative relationship between microbiota makeup and dysglycemia is still to be demonstrated.

  17. Thiol-based redox signaling in the nitrogen-fixing symbiosis

    Directory of Open Access Journals (Sweden)

    Pierre eFrendo

    2013-09-01

    Full Text Available In nitrogen poor soils legumes establish a symbiotic interaction with rhizobia that results in the formation of root nodules. These are unique plant organs where bacteria differentiate into bacteroids, which express the nitrogenase enzyme complex that reduces atmospheric N2 to ammonia. Nodule metabolism requires a tight control of the concentrations of reactive oxygen and nitrogen species (RONS so that they can perform useful signaling roles while avoiding nitro-oxidative damage. In nodules a thiol-dependent regulatory network that senses, transmits and responds to redox changes is starting to be elucidated. A combination of enzymatic, immunological, pharmacological and molecular analyses has allowed to conclude that glutathione and its legume-specific homolog, homoglutathione, are abundant in meristematic and infected cells, their spatio-temporally distribution is correlated with the corresponding (homoglutathione synthetase activities, and are crucial for nodule development and function. Glutathione is at high concentrations in the bacteroids and at moderate amounts in the mitochondria, cytosol and nuclei. Less information is available on other components of the network. The expression of multiple isoforms of glutathione peroxidases, peroxiredoxins, thioredoxins, glutaredoxins and NADPH-thioredoxin reductases has been detected in nodule cells using antibodies and proteomics. Peroxiredoxins and thioredoxins are essential to regulate and in some cases to detoxify RONS in nodules. Further research is necessary to clarify the regulation of the expression and activity of thiol redox-active proteins in response to abiotic, biotic and developmental cues, their interactions with downstream targets by disulfide-exchange reactions, and their participation in signaling cascades. The availability of mutants and transgenic lines will be crucial to facilitate systematic investigations into the function of the various proteins in the legume

  18. Denaturing gradient gel electrophoresis of neonatal intestinal microbiota in relation to the development of asthma

    Directory of Open Access Journals (Sweden)

    Desager Kristine N

    2011-04-01

    Full Text Available Abstract Background The extended 'hygiene hypothesis' suggests that the initial composition of the infant gut microbiota is a key determinant in the development of atopic disease. Several studies have demonstrated that the microbiota of allergic and non-allergic infants are different even before the development of symptoms, with a critical time window during the first 6 months of life. The aim of the study was to investigate the association between early intestinal colonisation and the development of asthma in the first 3 years of life using DGGE (denaturing gradient gel electrophoresis. Methods In a prospective birth cohort, 110 children were classified according to the API (Asthma Predictive Index. A positive index included wheezing during the first three years of life combined with eczema in the child in the first years of life or with a parental history of asthma. A fecal sample was taken at the age of 3 weeks and analysed with DGGE using universal and genus specific primers. Results The Asthma Predictive Index was positive in 24/110 (22% of the children. Using universal V3 primers a band corresponding to a Clostridum coccoides XIVa species was significantly associated with a positive API. A Bacteroides fragilis subgroup band was also significantly associated with a positive API. A final DGGE model, including both bands, allowed correct classification of 73% (80/110 of the cases. Conclusion Fecal colonisation at age 3 weeks with either a Bacteroides fragilis subgroup or a Clostridium coccoides subcluster XIVa species is an early indicator of possible asthma later in life. These findings need to be confirmed in a new longitudinal follow-up study.

  19. Prebiotic fibres dose-dependently increase satiety hormones and alter Bacteroidetes and Firmicutes in lean and obese JCR:LA-cp rats.

    Science.gov (United States)

    Parnell, Jill A; Reimer, Raylene A

    2012-02-01

    There is a growing interest in modulating gut microbiota with diet in the context of obesity. The purpose of the present study was to evaluate the dose-dependent effects of prebiotics (inulin and oligofructose) on gut satiety hormones, energy expenditure, gastric emptying and gut microbiota. Male lean and obese JCR:LA-cp rats were randomised to either of the following: lean 0 % fibre (LC), lean 10 % fibre (LF), lean 20 % fibre (LHF), obese 0 % fibre (OC), obese 10 % fibre (OF) or obese 20 % fibre (OHF). Body composition, gastric emptying, energy expenditure, plasma satiety hormone concentrations and gut microbiota (using quantitative PCR) were measured. Caecal proglucagon and peptide YY mRNA levels were up-regulated 2-fold in the LF, OF and OHF groups and 3-fold in the LHF group. Ghrelin O-acyltransferase mRNA levels were higher in obese v. lean rats and decreased in the OHF group. Plasma ghrelin response was attenuated in the LHF group. Microbial species measured in the Bacteroidetes division decreased, whereas those in the Firmicutes increased in obese v. lean rats and improved with prebiotic intake. Bifidobacterium and Lactobacillus increased in the OHF v. OC group. Bacteroides and total bacteria negatively correlated with percentage of body fat and body weight. Enterobacteriaceae increased in conjunction with glucose area under the curve (AUC) and glucagon-like peptide-1 AUC. Bacteroides and total bacteria correlated positively with ghrelin AUC yet negatively with insulin AUC and energy intake (P < 0·05). Several of the mechanisms through which prebiotics act (food intake, satiety hormones and alterations in gut microbiota) are regulated in a dose-dependent manner. The combined effects of prebiotics may have therapeutic potential for obesity.

  20. In vitro utilization of amylopectin and high-amylose maize (Amylomaize) starch granules by human colonic bacteria.

    Science.gov (United States)

    Wang, X; Conway, P L; Brown, I L; Evans, A J

    1999-11-01

    It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (starch.

  1. The intestinal ecosystem in chronic functional constipation.

    Science.gov (United States)

    Zoppi, G; Cinquetti, M; Luciano, A; Benini, A; Muner, A; Bertazzoni Minelli, E

    1998-08-01

    Chronic functional constipation is common in infants, and the bacterial composition of stools in this condition is not known. The study aims were to: (i) investigate the composition of the intestinal ecosystem in chronic functional constipation; (ii) establish whether the addition of the water-holding agent calcium polycarbophil to the diet induces an improvement in constipation; and (iii) determine the composition of the intestinal ecosystem after the use of this agent. In total, 42 children (20F, 22M; mean age: 8.6 +/- 2.9 y) were studied. Twenty-eight children with functional chronic constipation without anatomical disorders were treated double-blind in random sequence for 1 month with an oral preparation of calcium polycarbophil (0.62 g/twice daily) or placebo. Intestinal flora composition was evaluated by standard microbiological methods and biochemical assays on faecal samples collected before and after treatment. Fourteen healthy children were studied as controls. The results show that (i) the constipated children presented a significant increase in clostridia and bifidobacteria in faeces compared to healthy subjects--different species of clostridia and enterobacteriaceae were frequently isolated; no generalized overgrowth was observed; Clostridia outnumbered bacteroides and E. coli mean counts by 2-3log, while bacteroides and E. coli counts were similar (5-6 log10/g fresh faeces); these intestinal disturbances could be defined as a dysbiosis, i.e. a quantitative alteration in the relative proportions of certain intestinal bacterial species. (ii) Clinical resolution of constipation was achieved only in 43% of treated children and an improvement in 21% (one bowel movement every 2 d). (iii) Calcium polycarbophil treatment induced no significant changes in the composition of the intestinal ecosystem, nor in blood chemistry parameters.

  2. Helicobacter species ribosomal DNA in the pancreas, stomach and duodenum of pancreatic cancer patients

    Institute of Scientific and Technical Information of China (English)

    Hans-Olof Nilsson; Unne Stenram; Ingemar Ihse; Torkel Wadstr(o)m

    2006-01-01

    AIM: To determine whether gastric and enteric Helico-bacter species are associated with pancreatic cancer.METHODS: Patients with exocrine pancreatic cancer(n = 40), neuroendocrine cancer (n = 14), multipleendocrine neoplasia type 1 (n = 8), and chronic pan-creatitis (n = 5) were studied. Other benign pancreat-ic diseases (n = 10) and specimens of normal pancre-as (n = 7) were included as controls. Pancreatic tissuespecimens were analyzed by Helicobacter-specificPCR-assay and products were characterized by dena-turing gradient electrophoresis and DNA-sequencing.From a subset of the pancreatic cancer patients, gas-tric and/or duodenal tissue as well as gallbladder andductus choledochus tissue were analyzed. Gallbladderand choledochus samples were included as controls.Stomach and duodenum samples were investigated toanalyze whether a gastric helicobacter might dissemi-nate to the pancreas in pancreatic cancer patients.Pancreatic specimens were analyzed by Bacteroides-specific PCR for detecting the translocation of indig-enous gut microbes to the diseased pancreas.RESULTS: Helicobacter DNA was detected in pancreas(tumor and/or surrounding tissue) of 75% of patientswith exocrine cancer, 57% of patients with neuro-endocrine cancer, 38% of patients with multiple eh-docrine neoplasia, and 60% of patients with chronicpancreatitis. All samples from other benign pancreaticdiseases and normal pancreas were negative. Thirty-three percent of the patients were helicobacter-positive in gastroduodenal specimens. Surprisingly,H. bilis was identified in 60% of the positive gastro-duodenal samples. All gallbladder and ductus cho-ledochus specimens were negative for helicobacter.Bacteroides PCR-assay was negative for all pancreaticsamples.CONCLUSION: Helicobacter DNA commonly detectedin pancreatic cancer suggests a possible role of theemerging pathogens in the development of chronicpancreatitis and pancreatic cancer.

  3. Effect of Heat Stress on the Intestinal Flora Structure and Alkaline Phosphatase Activities and mRNA Expression of Amino Acid Transporters of Layer%热应激对蛋鸡肠道菌群结构、碱性磷酸酶活性及氨基酸转运载体mRNA表达丰度的影响

    Institute of Scientific and Technical Information of China (English)

    李永洙; 陈常秀; Yongquan Cui

    2013-01-01

    [目的]揭示热应激环境下蛋鸡肠道菌群结构、肠黏膜碱性磷酸酶活性和氨基酸转运载体mRNA表达量的变化机理。[方法]试验选择16周龄济宁百日鸡96只,随机分成对照组((24±1)℃;Ⅰ)和热应激((38±1)℃)组,各组设6个重复,每个重复8只,试验持续14 d。采用16S rDNA的PCR-DGGE技术和实时荧光定量PCR等手段,分析热应激2(Ⅱ)、7(Ⅲ)、14 d(Ⅳ)时,对十二指肠、空肠及回肠内容物菌群多样性和肠黏膜碱性磷酸酶活性以及氨基酸转运载体rBAT、y+LAT 1、CAT l mRNA基因表达的相对丰度变化规律。[结果]热应激7 d开始各肠段菌群多样性较为丰富,热应激7、14 d时空肠和回肠部位敏感乳杆菌(Lactobacillus agilis),回肠部位约氏乳杆菌(Lactobacillus johnsonii)、不可培养细菌(uncultured bacterium)和不可培养的拟杆菌属(uncultured Bacteroidalesbacterium)均末检测到;而热应激不同时间段空肠和回肠部位可检测到不可培养细菌、溃疡拟杆菌(Bacteroides helcogenes)、卵形拟杆菌(Bacteroides ovatus)、索氏志贺氏菌(Shigella sonnei);空肠和回肠部位黏膜上皮细胞表面的碱性磷酸酶活性与Ⅰ组比较显著下降(P<0.05);而空肠和回肠Ⅲ组的rBAT、y+LAT 1 mRNA表达丰度均最低,空肠在各热应激时段表达丰度变化幅度最大(P<0.05),回肠的CAT 1 mRNA表达丰度在Ⅲ、Ⅳ组与Ⅰ组比较影响更明显(P<0.01)。[结论]热应激对空肠和回肠部位微生物菌群影响较为明显,肠道微生物群落改变可导致肠道的消化吸收功能发生改变。%[Objective] The objective of this study is to reveal the influence mechanisms of heat stress affecting the intestinal flora structure of layer, the alkaline phosphatase activities of intestinal mucosa and the mRNA expression of amino acid transporters.[Method]A total of 96 Jining Bairi

  4. The changes and significances of intestinal microflora in patients with irritable bowel syndrome%肠易激综合征患者肠道菌群的变化及意义

    Institute of Scientific and Technical Information of China (English)

    胡乐义; 王巧民; 姜彬言; 王海浪; 宋继中; 叶飞

    2012-01-01

    To investigate the changes of irritable bowel syndrome( IBS ) intestinal microflorain patients, and explored the significances. Methods Fifty Rome Ⅲ criteria IBS patients and twenty-five healthy subjects were enrolled, fresh faecal samples were collected and the method established by Mit-suoka was used to quantitatively and qualitatively culture the fecal three kinds of anaerobes ( Bifidobacterium, Lactobacillus, Bacteroides ) and two kinds of aerobes ( Enterobacteriaceae, Enterococcus ). We also calculated the ratio of Bifidobacterium to Enterobacteriaceae ( B/E value ). Results Compared with healthy subjects, the number of fecal Enterobacteriaceae was significantly increased( P < 0. 05 ), Bifidobacterium, Lactobacillus and B/E value were significantly decreased in IBS patients ( P < 0. 05 ) , but the number of Bacteroides and Enterococcus were not significantly . Different types of IBS had dif- ferent changes of intestinal microflora, the number of fecal Enterobacteriaceae was significantly increased, the number of fecal Bifidobacterium, Lactobacillus and B/E value were significantly decreased in diarrhea-predominant IBS patients versus healthy subjects( P < 0. 05 ); compare with healthy subjects the level of fecal Bacteroides was significantly increased in constipation-predominant IBS( P < 0. 05 ), others were not significantly; compared with healthy subjects, the level of fecal Enterobacteriaceae was significantly increased, Lactobacillus and B/E value were significantly decreased in alterlated-predominant IBS patients ( P < 0. 05 ). Conclusion There are intestinal microflora disorders in IBS patients, B/E value is less than 1, the numbers of Enterobacteriaceae are significantly increased, the numbers of Bifidobacterium and Lactobacillus are significantly decreased. Different types of IBS have different changes of intestinal flora.%目的 了解肠易激综合征(IBS)患者肠道菌群变化情况并探讨其意义.方法 选取符合罗马Ⅲ标准的50

  5. Microbial Health Risks Associated with Exposure to Stormwater in a Water Plaza

    Science.gov (United States)

    Sales-Ortells, Helena; Medema, Gertjan

    2015-04-01

    Climate change scenarios predict an increase of intense rainfall events in summer in Western Europe. Current urban drainage systems cannot cope with such intense precipitation events. Cities are constructing local stormwater storage facilities to prevent pluvial flooding. Combining storage with other functions, such as recreation, may lead to exposure to contaminants. This study assessed the microbial quality of rainwater collected in a water plaza in Rotterdam (The Netherlands) and the health risks associated with recreational exposure. The water plaza collects street run-off, diverges first flush to the sewer system and stores the rest of the run-off in the plaza as open water. A rain simulation experiment was conducted using drinking water from fire hydrants. The water flowed over the street pavement into the street gutters and into the square. Samples were collected from the first flush diverted water and from two different levels of the water plaza at different points in time. Campylobacter spp., Cryptosporidium, and Legionella pneumophila were the pathogens investigated, using quantitative PCR. Escherichia coli was quantified with culture methods to obtain information on faecal contamination. Microbial source tracking tools (human Bacteroides, avian Helicobacter and canine mitochondrial DNA, all analysed with quantitative PCR) were used to determine the origin (human, animal) of the intestinal pathogens. To estimate the health risks for children playing in the water plaza after a rain event, a quantitative microbial risk assessment model was built. The volume of water ingested was obtained from literature on similar locations (flooded streets). Published dose-response models were used to calculate the risk per event. Exposure frequency was estimated using weather data (precipitation events). E. coli concentrations were below the level for excellent bathing water in the EU Bathing Water Directive. Cryptosporidium was not found in any sample. Campylobacter spp

  6. Cell Cycle Control by the Master Regulator CtrA in Sinorhizobium meliloti.

    Directory of Open Access Journals (Sweden)

    Francesco Pini

    2015-05-01

    Full Text Available In all domains of life, proper regulation of the cell cycle is critical to coordinate genome replication, segregation and cell division. In some groups of bacteria, e.g. Alphaproteobacteria, tight regulation of the cell cycle is also necessary for the morphological and functional differentiation of cells. Sinorhizobium meliloti is an alphaproteobacterium that forms an economically and ecologically important nitrogen-fixing symbiosis with specific legume hosts. During this symbiosis S. meliloti undergoes an elaborate cellular differentiation within host root cells. The differentiation of S. meliloti results in massive amplification of the genome, cell branching and/or elongation, and loss of reproductive capacity. In Caulobacter crescentus, cellular differentiation is tightly linked to the cell cycle via the activity of the master regulator CtrA, and recent research in S. meliloti suggests that CtrA might also be key to cellular differentiation during symbiosis. However, the regulatory circuit driving cell cycle progression in S. meliloti is not well characterized in both the free-living and symbiotic state. Here, we investigated the regulation and function of CtrA in S. meliloti. We demonstrated that depletion of CtrA cause cell elongation, branching and genome amplification, similar to that observed in nitrogen-fixing bacteroids. We also showed that the cell cycle regulated proteolytic degradation of CtrA is essential in S. meliloti, suggesting a possible mechanism of CtrA depletion in differentiated bacteroids. Using a combination of ChIP-Seq and gene expression microarray analysis we found that although S. meliloti CtrA regulates similar processes as C. crescentus CtrA, it does so through different target genes. For example, our data suggest that CtrA does not control the expression of the Fts complex to control the timing of cell division during the cell cycle, but instead it negatively regulates the septum-inhibiting Min system. Our

  7. Cell Cycle Control by the Master Regulator CtrA in Sinorhizobium meliloti.

    Science.gov (United States)

    Pini, Francesco; De Nisco, Nicole J; Ferri, Lorenzo; Penterman, Jon; Fioravanti, Antonella; Brilli, Matteo; Mengoni, Alessio; Bazzicalupo, Marco; Viollier, Patrick H; Walker, Graham C; Biondi, Emanuele G

    2015-05-01

    In all domains of life, proper regulation of the cell cycle is critical to coordinate genome replication, segregation and cell division. In some groups of bacteria, e.g. Alphaproteobacteria, tight regulation of the cell cycle is also necessary for the morphological and functional differentiation of cells. Sinorhizobium meliloti is an alphaproteobacterium that forms an economically and ecologically important nitrogen-fixing symbiosis with specific legume hosts. During this symbiosis S. meliloti undergoes an elaborate cellular differentiation within host root cells. The differentiation of S. meliloti results in massive amplification of the genome, cell branching and/or elongation, and loss of reproductive capacity. In Caulobacter crescentus, cellular differentiation is tightly linked to the cell cycle via the activity of the master regulator CtrA, and recent research in S. meliloti suggests that CtrA might also be key to cellular differentiation during symbiosis. However, the regulatory circuit driving cell cycle progression in S. meliloti is not well characterized in both the free-living and symbiotic state. Here, we investigated the regulation and function of CtrA in S. meliloti. We demonstrated that depletion of CtrA cause cell elongation, branching and genome amplification, similar to that observed in nitrogen-fixing bacteroids. We also showed that the cell cycle regulated proteolytic degradation of CtrA is essential in S. meliloti, suggesting a possible mechanism of CtrA depletion in differentiated bacteroids. Using a combination of ChIP-Seq and gene expression microarray analysis we found that although S. meliloti CtrA regulates similar processes as C. crescentus CtrA, it does so through different target genes. For example, our data suggest that CtrA does not control the expression of the Fts complex to control the timing of cell division during the cell cycle, but instead it negatively regulates the septum-inhibiting Min system. Our findings provide valuable

  8. Effect of water stress on nitrogen fixation and nodule structure of common bean Efeito do estresse hídrico na fixação biológica de nitrogênio e estrutura de nódulos de feijão

    Directory of Open Access Journals (Sweden)

    Maria Lucrecia Gerosa Ramos

    2003-03-01

    Full Text Available The aim of this work was to investigate the effect of water stress on N2 fixation and nodule structure of two common bean (Phaseolus vulgaris L. cultivars Carioca and EMGOPA-201. Plants were harvested after five and eight days of water stress. Carioca had lower nodule dry weight on both water stress periods; shoot dry weight was lower at five days water stress and did not differ from control after eight days stress. Both cultivars had lower nitrogenase activity than control after five and eight days water stress. For both cultivars, after eight days stress bacteroid membranes were damaged. Carioca presented more pronounced damage to infected tissue, with host cell vacuolation and loss of the peribacteroid membrane at five days after stress; at eight days after stress, there was degradation of cytoplasm host cells and senescence of bacteroids, with their release into intercellular spaces. Intensity of immunogold-labeling of intercellular cortical glycoprotein with the monoclonal antibodies MAC 236/265 was different for both cultivars.O objetivo deste trabalho foi investigar o efeito do estresse hídrico na fixação biológica do N2 e na estrutura dos nódulos de feijão (Phaseolus vulgaris L., nas cultivares Carioca e EMGOPA-201. As plantas foram colhidas após cinco e oito dias de estresse hídrico. A cultivar Carioca apresentou menor peso seco de nódulos que o controle (plantas irrigadas. O peso da parte aérea seca da cultivar Carioca foi menor aos cinco dias de estresse hídrico e não diferiu do controle, após oito dias de estresse. As duas cultivares tiveram menor atividade da nitrogenase após cinco e oito dias de estresse hídrico e apresentaram danos na membrana peribacteróide após oito dias de estresse. A cultivar Carioca foi mais afetada do que a EMGOPA-201, com vacuolação das células e perda da membrana peribacteróide após cinco dias de estresse; aos oito dias, houve degradação das células do citoplasma, senescência e

  9. Characterization of fecal indicator bacteria in sediments cores from the largest freshwater lake of Western Europe (Lake Geneva, Switzerland).

    Science.gov (United States)

    Thevenon, Florian; Regier, Nicole; Benagli, Cinzia; Tonolla, Mauro; Adatte, Thierry; Wildi, Walter; Poté, John

    2012-04-01

    This study characterized the fecal indicator bacteria (FIB), including Escherichia coli (E. coli) and Enteroccocus (ENT), disseminated over time in the Bay of Vidy, which is the most contaminated area of Lake Geneva. Sediments were collected from a site located at ∼500 m from the present waste water treatment plant (WWTP) outlet pipe, in front of the former WWTP outlet pipe, which was located at only 300 m from the coastal recreational area (before 2001). E. coli and ENT were enumerated in sediment suspension using the membrane filter method. The FIB characterization was performed for human Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium) and human specific bacteroides by PCR using specific primers and a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Bacterial cultures revealed that maximum values of 35.2 × 10(8) and 6.6 × 10(6)CFU g(-1) dry sediment for E. coli and ENT, respectively, were found in the sediments deposited following eutrophication of Lake Geneva in the 1970s, whereas the WWTP started operating in 1964. The same tendency was observed for the presence of human fecal pollution: the percentage of PCR amplification with primers ESP-1/ESP-2 for E. faecalis and E. faecium indicated that more than 90% of these bacteria were from human origin. Interestingly, the PCR assays for specific-human bacteroides HF183/HF134 were positive for DNA extracted from all isolated strains of sediment surrounding WWPT outlet pipe discharge. The MALDI-TOF MS confirmed the presence of general E. coli and predominance E. faecium in isolated strains. Our results demonstrated that human fecal bacteria highly increased in the sediments contaminated with WWTP effluent following the eutrophication of Lake Geneva. Additionally, other FIB cultivable strains from animals or adapted environmental strains were detected in the sediment of the bay. The approaches used in this research are valuable to assess the

  10. Analysis on intestinal flora changes in patients with diarrhea%大连市57例腹泻患者肠道菌群变化的分析

    Institute of Scientific and Technical Information of China (English)

    朱伟

    2013-01-01

    目的 研究急性和慢性腹泻患者与正常人的肠道菌群变化差异.方法 对慢性腹泻组22例、急性腹泻组35例,对照组20例的成年患者粪便进行肠杆菌、肠球菌、双歧杆菌、乳酸杆菌检测分析与比较.结果 急性腹泻患者与对照组相比肠杆菌显著增加,而双歧杆菌、乳酸杆菌、类杆菌及肠球菌显著减少(P<0.01),慢性腹泻患者的肠杆菌明显增加,乳酸杆菌明显减少(P<0.05),双歧杆菌、类杆菌及肠球菌较对照组减少,但结果差异无统计学意义.急性腹泻者厌氧菌较慢性腹泻者有所减少,其中类杆菌和乳杆菌显著减少(P<0.05).结论 无论急慢性腹泻患者都存在肠道菌群失调的情况,其中急性腹泻患者更加明显.%Objective To investigate the changes in the intestinal flora of patients with acute and chronic diarrhea.Methods With 22 patients as the chronic diarrhea group,35 patients as the acute diarrhea group and 20 healthy adults as the control group,the faecel specimens of all three groups were detected for Enterobacilli,Enterococci,Bifidobactenia,Lactobacilli and Bacteroides; the results were analyzed and compared.Results The colony forming units of Enterobacterium of acute diarrhea group increased and those of Enterococcus,Bifidobacterum,Lactobacillum and Bacteroides decreased,comparing with the control group (P < 0.01) ; the units of Enterobacterium increased and that of Lactobacillum decreased in patients with chronic diarrhea (P < 0.05).Moreover,the numbers of Bateroides and Lactobacillum in patients with chronic diarrhea decreased less significantly than that in patients with acute patients (P < 0.05).Conclusion Both patients with acute and chronic diarrhea have intestinal dysbacteriosis,and the intestinal flora in patients with acute diarrhea was disturbed more severely than those with chronic diarrhea.

  11. Occurrence and distribution of microbiological contamination and enteric viruses in shallow ground water in Baltimore and Harford counties, Maryland

    Science.gov (United States)

    Banks, William S.L.; Battigelli, David A.

    2002-01-01

    The U.S. Geological Survey, in cooperation with the Maryland Department of the Environment and the Wisconsin State Laboratory of Hygiene, conducted a study to characterize the occurrence and distribution of viral contamination in small (withdrawing less than 10,000 gallons per day) public water-supply wells screened in the shallow aquifer in the Piedmont Physiographic Province in Baltimore and Harford Counties, Maryland. Two hundred sixty-three small public water-supply wells were in operation in these counties during the spring of 2000. Ninety-one of these sites were selected for sampling using a methodology that distributed the samples evenly over the population and the spatial extent of the study area. Each site, and its potential susceptibility to microbiological contamination, was evaluated with regard to hole depth, casing interval, and open interval. Each site was evaluated using characteristics such as on-site geology and on-site land use.Samples were collected by pumping between 200 and 400 gallons of untreated well water through an electropositive cartridge filter. Water concentrates were subjected to cell-culture assay for the detection of culturable viruses and reverse-transcription polymerase chain reaction/gene probe assays to detect viral ribonucleic acid; grab samples were analyzed for somatic and male-specific coliphages, Bacteroides fragilis, Clostridium perfringens, enterococci, Escherichia coli, total coliforms, total oxidized nitrogen, nitrite, organic nitrogen, total phosphate, ortho-phosphate, calcium, magnesium, sodium, potas-sium, chloride, sulfate, iron, acid-neutralizing capacity, pH, specific conductance, temperature, and dissolved oxygen.One sample tested positive for the presence of the ribonucleic acid of rotavirus through poly-merase chain-reaction analysis. Twenty-nine per-cent of the samples (26 of 90) had bacterial con-tamination. About 7 percent of the samples (6 of 90) were contaminated with either male-specific coliphage

  12. Ground-water quality and discharge to Chincoteague and Sinepuxent Bays adjacent to Assateague Island National Seashore, Maryland

    Science.gov (United States)

    Dillow, Jonathan J.A.; Banks, William S.L.; Smigaj, Michael J.

    2002-01-01

    The U.S. Geological Survey, in cooperation with the Maryland Department of the Environment and the Wisconsin State Laboratory of Hygiene, conducted a study to characterize the occurrence and distribution of viral contamination in small (withdrawing less than 10,000 gallons per day) public water-supply wells screened in the shallow aquifer in the Piedmont Physiographic Province in Baltimore and Harford Counties, Maryland. Two hundred sixty-three small public water-supply wells were in operation in these counties during the spring of 2000. Ninety-one of these sites were selected for sampling using a methodology that distributed the samples evenly over the population and the spatial extent of the study area. Each site, and its potential susceptibility to microbiological contamination, was evaluated with regard to hole depth, casing interval, and open interval. Each site was evaluated using characteristics such as on-site geology and on-site land use.Samples were collected by pumping between 200 and 400 gallons of untreated well water through an electropositive cartridge filter. Water concentrates were subjected to cell-culture assay for the detection of culturable viruses and reverse-transcription polymerase chain reaction/gene probe assays to detect viral ribonucleic acid; grab samples were analyzed for somatic and male-specific coliphages, Bacteroides fragilis, Clostridium perfringens, enterococci, Escherichia coli, total coliforms, total oxidized nitrogen, nitrite, organic nitrogen, total phosphate, ortho-phosphate, calcium, magnesium, sodium, potas-sium, chloride, sulfate, iron, acid-neutralizing capacity, pH, specific conductance, temperature, and dissolved oxygen.One sample tested positive for the presence of the ribonucleic acid of rotavirus through poly-merase chain-reaction analysis. Twenty-nine per-cent of the samples (26 of 90) had bacterial con-tamination. About 7 percent of the samples (6 of 90) were contaminated with either male-specific coliphage

  13. Effect of Green Tea Infusions on Obesity-associated Gut Microbiota%绿茶茶汤对肥胖相关肠道菌群的影响

    Institute of Scientific and Technical Information of China (English)

    郭虹雯; 许翔雨; 陈莹婕; 倪莉; 刘志彬

    2016-01-01

    近年来,饮茶调节肠道微生态的效果受到广泛关注。本研究通过将绿茶茶汤与志愿者新鲜粪样混合培养,使用荧光原位杂交技术考察不同发酵时间点(0、6、12、24 h)绿茶茶汤对与肥胖密切相关的肠道菌群(包括总菌、拟杆菌门微生物和厚壁菌门微生物)的影响,从而评估绿茶茶汤调节肠道微生态作用的效果。实验结果表明,绿茶茶汤在体外粪样混合培养体系中发酵24 h 时,对于肠道中总菌、拟杆菌门微生物以及厚壁菌门微生物的数量减少有抑制效果(P<0.05),并可以改善肠道中拟杆菌门与厚壁菌门的相对丰度,降低厚壁菌门与拟杆菌门比例(F/B),这为饮茶对改善肠道健康、减肥降脂作用提供了一定的理论参考。%In recent years, the effect of tea on intestinal microflora attracted widespread attention. In this study, the green tea infusion with human fecal was mixed, the change of intestinal flora related to obesity in different fermentation time points (0, 6, 12, 24 h) were measured and the role of tea regulated intestinal microflora was evaluated. The results showed that green tea infusion inhibited the reduction of total gut bacteria, Bacteroides and Firmicutes after fermentation for 24 h (P<0.05), improved the relative abundance of Bacteroides and Firmicutes, reduced the F/B ratio, which provides a reference to support the important role of green tea infusion in improving intestinal health, reducing weight and lowering blood lipid.

  14. Rhizobial exopolysaccharides: genetic control and symbiotic functions

    Directory of Open Access Journals (Sweden)

    Mazur Andrzej

    2006-02-01

    Full Text Available Abstract Specific complex interactions between soil bacteria belonging to Rhizobium, Sinorhizobium, Mesorhizobium, Phylorhizobium, Bradyrhizobium and Azorhizobium commonly known as rhizobia, and their host leguminous plants result in development of root nodules. Nodules are new organs that consist mainly of plant cells infected with bacteroids that provide the host plant with fixed nitrogen. Proper nodule development requires the synthesis and perception of signal molecules such as lipochitooligosaccharides, called Nod factors that are important for induction of nodule development. Bacterial surface polysaccharides are also crucial for establishment of successful symbiosis with legumes. Sugar polymers of rhizobia are composed of a number of different polysaccharides, such as lipopolysaccharides (LPS, capsular polysaccharides (CPS or K-antigens, neutral β-1, 2-glucans and acidic extracellular polysaccharides (EPS. Despite extensive research, the molecular function of the surface polysaccharides in symbiosis remains unclear. This review focuses on exopolysaccharides that are especially important for the invasion that leads to formation of indetermined (with persistent meristem type of nodules on legumes such as clover, vetch, peas or alfalfa. The significance of EPS synthesis in symbiotic interactions of Rhizobium leguminosarum with clover is especially noticed. Accumulating data suggest that exopolysaccharides may be involved in invasion and nodule development, bacterial release from infection threads, bacteroid development, suppression of plant defense response and protection against plant antimicrobial compounds. Rhizobial exopolysaccharides are species-specific heteropolysaccharide polymers composed of common sugars that are substituted with non-carbohydrate residues. Synthesis of repeating units of exopolysaccharide, their modification, polymerization and export to the cell surface is controlled by clusters of genes, named exo/exs, exp or

  15. Cell Cycle Control by the Master Regulator CtrA in Sinorhizobium meliloti

    Science.gov (United States)

    Ferri, Lorenzo; Penterman, Jon; Fioravanti, Antonella; Brilli, Matteo; Mengoni, Alessio; Bazzicalupo, Marco; Viollier, Patrick H.; Walker, Graham C.; Biondi, Emanuele G.

    2015-01-01

    In all domains of life, proper regulation of the cell cycle is critical to coordinate genome replication, segregation and cell division. In some groups of bacteria, e.g. Alphaproteobacteria, tight regulation of the cell cycle is also necessary for the morphological and functional differentiation of cells. Sinorhizobium meliloti is an alphaproteobacterium that forms an economically and ecologically important nitrogen-fixing symbiosis with specific legume hosts. During this symbiosis S. meliloti undergoes an elaborate cellular differentiation within host root cells. The differentiation of S. meliloti results in massive amplification of the genome, cell branching and/or elongation, and loss of reproductive capacity. In Caulobacter crescentus, cellular differentiation is tightly linked to the cell cycle via the activity of the master regulator CtrA, and recent research in S. meliloti suggests that CtrA might also be key to cellular differentiation during symbiosis. However, the regulatory circuit driving cell cycle progression in S. meliloti is not well characterized in both the free-living and symbiotic state. Here, we investigated the regulation and function of CtrA in S. meliloti. We demonstrated that depletion of CtrA cause cell elongation, branching and genome amplification, similar to that observed in nitrogen-fixing bacteroids. We also showed that the cell cycle regulated proteolytic degradation of CtrA is essential in S. meliloti, suggesting a possible mechanism of CtrA depletion in differentiated bacteroids. Using a combination of ChIP-Seq and gene expression microarray analysis we found that although S. meliloti CtrA regulates similar processes as C. crescentus CtrA, it does so through different target genes. For example, our data suggest that CtrA does not control the expression of the Fts complex to control the timing of cell division during the cell cycle, but instead it negatively regulates the septum-inhibiting Min system. Our findings provide valuable

  16. Real-time analysis of gut flora in Entamoeba histolytica infected patients of Northern India

    Directory of Open Access Journals (Sweden)

    Verma Anil Kumar

    2012-08-01

    Full Text Available Abstract Background Amebic dysentery is caused by the protozoan parasite Entamoeba histolytica and the ingestion of quadrinucleate cyst of E. histolytica from fecally contaminated food or water initiates infection. Excystation occurs in the lumen of small intestine, where motile and potentially invasive trophozoites germinate from cysts. The ability of trophozoites to interact and digest gut bacteria is apparently important for multiplication of the parasite and its pathogenicity; however the contribution of resident bacterial flora is not well understood. We quantified the population of Bacteroides, Bifidobacterium, Ruminococcus, Lactobacillus, Clostridium leptum subgroup, Clostridium coccoides subgroup, Eubacterium, Campylobacter, Methanobrevibacter smithii and Sulphur reducing bacteria using genus specific primers in healthy (N = 22 vs amebic patients (E. histolytica positive, N = 17 stool samples by Real-time PCR. Results Absolute quantification of Bacteroides (p = .001, Closrtridium coccoides subgroup (p = 0.002, Clostridium leptum subgroup (p = 0.0001, Lactobacillus (p = 0.037, Campylobacter (p = 0.0014 and Eubacterium (p = 0.038 show significant drop in their population however, significant increase in Bifdobacterium (p = 0.009 was observed where as the population of Ruminococcus (p = 0.33 remained unaltered in healthy vs amebic patients (E. histolytica positive. We also report high prevalence of nimE gene in stool samples of both healthy volunteers and amebic patients. No significant decrease in nimE gene copy number was observed before and after the treatment with antiamebic drug. Conclusions Our results show significant alteration in predominant gut bacteria in E. histolytica infected individuals. The frequent episodes of intestinal amoebic dysentery thus result in depletion of few predominant genera in gut that may lead to poor digestion and absorption of food in intestine. It further disturbs

  17. The comparison of the vaginal bacterial microbiota in healthy and metritic dairy cows%健康与子宫内膜炎奶牛阴道菌群结构的比较研究

    Institute of Scientific and Technical Information of China (English)

    孙城涛; 赵静; 王军; 李向楠; 吕文发

    2014-01-01

    利用16S rDNA结合PCR-DGGE技术分析比较了产后45 d健康奶牛和患子宫内膜炎奶牛阴道内细菌群落多样性及其差异,并通过切胶、克隆测序等步骤分析了奶牛阴道细菌种类.研究结果表明,患病奶牛DGGE图谱的条带数量、多样性指数均显著高于健康奶牛;健康奶牛阴道优势菌主要有清酒乳杆菌(Lactobacillus sakei subsp.)、魏斯杆菌(Weissella koreensis sp.)和地衣芽孢杆菌(Bacillus licheniformis),而患病组奶牛阴道内此3种优势菌含量显著降低或缺失,且也无其他明显优势菌存在;从健康和患病奶牛阴道内均分离出脆弱拟杆菌(Bacteroides fragilis)、溃疡拟杆菌(Bacteroides helcogenes)、无乳支原体(Mycoplasma agalactiae)、普氏菌(Prevotella dentalis)、产气荚膜梭菌(Clostridium perfringens str.)和肠球菌(Enterococcus hirae)等常见病原微生物,在患病奶牛阴道内分离出大肠杆菌(Escherichia coli str.K-12 substr.)、梭杆菌(Fusobacterium nucleatum subsp.)等特定致病菌.研究结果提示,子宫内膜炎奶牛阴道内菌群结构比健康奶牛更为复杂,且无优势菌,阴道菌群结构失衡可能是奶牛发生子宫内膜炎的原因.

  18. Effects of dietary combinations of organic acids and medium chain fatty acids on the gastrointestinal microbial ecology and bacterial metabolites in the digestive tract of weaning piglets.

    Science.gov (United States)

    Zentek, J; Ferrara, F; Pieper, R; Tedin, L; Meyer, W; Vahjen, W

    2013-07-01

    Organic short and medium chain fatty acids are used in diets for piglets because they have an impact on the digestive processes and the intestinal microbiota. In this study, 48 pens (2 piglets/pen) were assigned randomly to 4 diets, without additive (control), with organic acids (OA; 0.416% fumaric and 0.328% lactic acid), with medium chain fatty acids (MCFA; 0.15% caprylic and capric acid), and a combination of OA and MCFA, to assess changes in the gastrointestinal microbiota with 12 pens per diet. Eight to nine piglets from each group were euthanized after 4 wk. Organic acids, MCFA, and pH in the digesta were determined and the intestinal microbiota was quantified by real-time PCR. The different diets had no effect on the growth performance. Concentration of added fumaric acid was below the detection limit in the upper small intestine whereas the concentration of lactic acid in the digesta was not affected by the treatments. The added MCFA was recovered in the MCFA treated groups in the stomach, but the concentrations declined in the upper small intestine. Concentration of short chain fatty acids was reduced in the colon digesta in piglets fed diets with OA compared with those fed unsupplemented diets (P = 0.029). The MCFA resulted in a pH reduction of the digesta, likely because of the effect on bacterial acid production. The addition of OA increased cell counts of Bacteroides-Porphyromonas-Prevotella group and clostridial clusters XIVa, I, and IV in the stomach, the clostridial cluster XIVa in the jejunum, and Bacteroides-Porphyromonas-Prevotella in the ileum and reduced counts of Streptococcus spp. in the colon (P < 0.05). The MCFA induced only minor changes in the gastrointestinal microbiota but increased cell counts for the Escherichia-Hafnia-Shigella group in the jejunum and the clostridial cluster XIVa in the colon digesta (P < 0.05). In the colon of piglets fed diets with organic OA, reduced mean cell counts of STb (est-II) positive Escherichia coli were

  19. The use of genomic DNA fingerprinting in studies of the epidemiology of bacteria in periodontitis.

    Science.gov (United States)

    Genco, R J; Loos, B G

    1991-07-01

    Recent studies of microbial epidemiology emphasizing the genetic organization and distribution of organisms associated with orofacial infections have led to new insights into the possible origins of pathogenicity. Studies into genetic heterogeneity, acquisition and transmission of these organisms have been markedly advanced by the utilization of the powerful technique of genomic DNA fingerprinting. Characteristic fingerprints for each bacterial isolate can be produced by cleavage of high molecular weight genomic DNA by restriction endonucleases. It is assumed that each DNA fingerprint represents a clonal type. In this report, we review and analyze studies of the epidemiology of bacteria associated with orofacial infections with an emphasis on periodontal disease. Studies of nontypable (NT) Haemophilus influenzae associated with recurrent otitis media illustrate the utility of this technique. DNA fingerprinting clearly demonstrates genetic heterogeneity of NT H. influenzae isolates, and clonality of infection of any individual. Furthermore, DNA fingerprinting has shown that the same clonal type is seen in siblings concurrently suffering from otitis media, suggesting horizontal transmission within the family. Studies of mutans Streptococci also show extensive genetic heterogeneity and show vertical transmission of a predominant clonal type only from mother to infant, but not from father to infant. Studies of Actinobacillus actinomycetemcomitans show considerable genetic heterogeneity among monkey isolates. Thus far, three clonal types have been reported with DNA fingerprinting among isolates from periodontal patients, but additional genetic heterogeneity can be found using specific DNA fragments as probes in hybridization experiments. Intrafamilial transmission of A. actinomycetemcomitans has been demonstrated. Porphyromonas (Bacteroides) gingivalis shows extensive genetic heterogeneity and case reports suggest clonal infection of any one individual. In contrast

  20. Local structure based method for prediction of the biochemical function of proteins: Applications to glycoside hydrolases.

    Science.gov (United States)

    Parasuram, Ramya; Mills, Caitlyn L; Wang, Zhouxi; Somasundaram, Saroja; Beuning, Penny J; Ondrechen, Mary Jo

    2016-01-15

    Thousands of protein structures of unknown or uncertain function have been reported as a result of high-throughput structure determination techniques developed by Structural Genomics (SG) projects. However, many of the putative functional assignments of these SG proteins in the Protein Data Bank (PDB) are incorrect. While high-throughput biochemical screening techniques have provided valuable functional information for limited sets of SG proteins, the biochemical functions for most SG proteins are still unknown or uncertain. Therefore, computational methods for the reliable prediction of protein function from structure can add tremendous value to the existing SG data. In this article, we show how computational methods may be used to predict the function of SG proteins, using examples from the six-hairpin glycosidase (6-HG) and the concanavalin A-like lectin/glucanase (CAL/G) superfamilies. Using a set of predicted functional residues, obtained from computed electrostatic and chemical properties for each protein structure, it is shown that these superfamilies may be sorted into functional families according to biochemical function. Within these superfamilies, a total of 18 SG proteins were analyzed according to their predicted, local functional sites: 13 from the 6-HG superfamily, five from the CAL/G superfamily. Within the 6-HG superfamily, an uncharacterized protein BACOVA_03626 from Bacteroides ovatus (PDB 3ON6) and a hypothetical protein BT3781 from Bacteroides thetaiotaomicron (PDB 2P0V) are shown to have very strong active site matches with exo-α-1,6-mannosidases, thus likely possessing this function. Also in this superfamily, it is shown that protein BH0842, a putative glycoside hydrolase from Bacillus halodurans (PDB 2RDY), has a predicted active site that matches well with a known α-L-galactosidase. In the CAL/G superfamily, an uncharacterized glycosyl hydrolase family 16 protein from Mycobacterium smegmatis (PDB 3RQ0) is shown to have local structural

  1. ISOLATION OF ANAEROBES IN DEEP SEATED PRESSURE ULCERS USING A NOVEL INNOVATIVE TECHNIQUE OF ANAEROBE ISOLATION

    Directory of Open Access Journals (Sweden)

    Lalbiaktluangi

    2015-12-01

    Full Text Available BACKGROUND Isolation of an anaerobe is usually neglected in hospitals with limited resources due to the expensive and complicated technique of anaerobic isolation methods, which is difficult to arrange in such resource poor settings. Conventionally adopted anaerobic culture methods such as Anaerobic jar, Gas-Pak, Anoxomat or Automated glove-box systems are extremely costly and cumbersome for single unit testing, but not suitable for small scale laboratories. However, anaerobic bacteria are not to be overlooked as they have made a comeback in clinical settings and are even showing resistance to Metronidazole, once thought to be the gold standard bullet against anaerobes. Deep seated pressure ulcers are usually the site where anaerobe causes an infection in synergy with aerobes. AIMS AND OBJECTIVES Isolation of anaerobes in deep seated pressure ulcers using a novel innovative technique and to study their antibiogram profile. MATERIALS AND METHODS Swabs taken from depth of deep seated pressure ulcers were immediately inoculated in Brucella blood agar at bedside and placed in polycarbonate airtight jar for anaerobic incubation using a novel innovative Modified Candle Jar technique. In this technique five grams of grease-free grade zero steel wool were dipped in 50ml freshly prepared acidified copper sulphate solution until the copper colour appeared. Excess solution was drained and the steel wool was moulded into a loose pad to fit on an open Petri plate placed on top of the inoculated Brucella blood agar plates. A white-wax candle was placed at the centre of this plate. A small test tube containing mixture of 0.5g sodium-bicarbonate and 0.5g magnesium carbonate was kept ready to be placed inside the jar, just after placing the inoculated plate and incubated for 48 hours. RESULTS Peptostreptococcus anaerobius and Bacteroides fragilis were successfully isolated from deep seated pressure ulcers by this method. Antibiogram studies were done using the

  2. Phylogeny and molecular signatures (conserved proteins and indels that are specific for the Bacteroidetes and Chlorobi species

    Directory of Open Access Journals (Sweden)

    Lorenzini Emily

    2007-05-01

    Full Text Available Abstract Background The Bacteroidetes and Chlorobi species constitute two main groups of the Bacteria that are closely related in phylogenetic trees. The Bacteroidetes species are widely distributed and include many important periodontal pathogens. In contrast, all Chlorobi are anoxygenic obligate photoautotrophs. Very few (or no biochemical or molecular characteristics are known that are distinctive characteristics of these bacteria, or are commonly shared by them. Results Systematic blast searches were performed on each open reading frame in the genomes of Porphyromonas gingivalis W83, Bacteroides fragilis YCH46, B. thetaiotaomicron VPI-5482, Gramella forsetii KT0803, Chlorobium luteolum (formerly Pelodictyon luteolum DSM 273 and Chlorobaculum tepidum (formerly Chlorobium tepidum TLS to search for proteins that are uniquely present in either all or certain subgroups of Bacteroidetes and Chlorobi. These studies have identified > 600 proteins for which homologues are not found in other organisms. This includes 27 and 51 proteins that are specific for most of the sequenced Bacteroidetes and Chlorobi genomes, respectively; 52 and 38 proteins that are limited to species from the Bacteroidales and Flavobacteriales orders, respectively, and 5 proteins that are common to species from these two orders; 185 proteins that are specific for the Bacteroides genus. Additionally, 6 proteins that are uniquely shared by species from the Bacteroidetes and Chlorobi phyla (one of them also present in the Fibrobacteres have also been identified. This work also describes two large conserved inserts in DNA polymerase III (DnaE and alanyl-tRNA synthetase that are distinctive characteristics of the Chlorobi species and a 3 aa deletion in ClpB chaperone that is mainly found in various Bacteroidales, Flavobacteriales and Flexebacteraceae, but generally not found in the homologs from other organisms. Phylogenetic analyses of the Bacteroidetes and Chlorobi species is also

  3. Effects of low levels of ciprofloxacin on a chemostat model of the human colonic microflora.

    Science.gov (United States)

    Carman, R J; Woodburn, M A

    2001-06-01

    To study the utility of an in vitro model system for assessing the effect of low concentrations of a fluoroquinolone (FQ) drug on the ecology of the human intestinal microflora, chemostats containing human fecal flora were exposed to 0.43, 4.3, and 43microg of ciprofloxacin (CI) per milliliter. Prior to and during drug exposure, we assayed short-chain fatty acids (SCFA), bacterial populations, and the relative levels of susceptibility of these populations to CI and trovafloxacin (TV), a newer related FQ with increased activity against anaerobes. The degree to which CI affected the chemostat ecology was measured statistically by comparing observed data with the corresponding predicted "no effect" level. No changes in total SCFA were observed; only butyrate was significantly higher at the intermediate and high-dose levels. Enterococci counts and the levels of susceptibility to CI among enterococci were also unaffected. Escherichia coli counts decreased in a dose-dependent manner. Susceptibility levels in E. coli followed no interpretable pattern. Bacteroides fragilis group (BfG) counts decreased significantly following exposure to 43 and 4.3microg/mL CI. Ciprofloxacin susceptibility among the BfG in these chemostats was not determined because the BfG counts were too low (less than 30 colonies per plate) when undiluted chemostat samples were plated. However, within 2 days of exposure to 0.43microg/mL CI, the percentage of BfG resistant to 4microg/mL CI increased to over 95%. Before exposure, all BfG were susceptible to both CI (2microg/mL) and TV (0.25microg/mL). All BfG isolated during exposure were resistant to both CI (4microg/mL) and TV (2microg/mL). Resistance selection in the BfG was unexpected as the MIC(90) of CI for B. fragilis is 8microg/mL. Since the average colon flora is about 20% B. fragilis and other bacteroides, CI may impact the human gut flora even at subtherapeutic levels.

  4. Integrated analysis of water quality parameters for cost-effective faecal pollution management in river catchments.

    Science.gov (United States)

    Nnane, Daniel Ekane; Ebdon, James Edward; Taylor, Huw David

    2011-03-01

    In many parts of the world, microbial contamination of surface waters used for drinking, recreation, and shellfishery remains a pervasive risk to human health, especially in Less Economically Developed Countries (LEDC). However, the capacity to provide effective management strategies to break the waterborne route to human infection is often thwarted by our inability to identify the source of microbial contamination. Microbial Source Tracking (MST) has potential to improve water quality management in complex river catchments that are either routinely, or intermittently contaminated by faecal material from one or more sources, by attributing faecal loads to their human or non-human sources, and thereby supporting more rational approaches to microbial risk assessment. The River Ouse catchment in southeast England (U.K.) was used as a model with which to investigate the integration and application of a novel and simple MST approach to monitor microbial water quality over one calendar year, thereby encompassing a range of meteorological conditions. A key objective of the work was to develop simple low-cost protocols that could be easily replicated. Bacteriophages (viruses) capable of infecting a human specific strain of Bacteroides GB-124, and their correlation with presumptive Escherichia coli, were used to distinguish sources of faecal pollution. The results reported here suggest that in this river catchment the principal source of faecal pollution in most instances was non-human in origin. During storm events, presumptive E. coli and presumptive intestinal enterococci levels were 1.1-1.2 logs higher than during dry weather conditions, and levels of the faecal indicator organisms (FIOs) were closely associated with increased turbidity levels (presumptive E. coli and turbidity, r = 0.43). Spatio-temporal variation in microbial water quality parameters was accounted for by three principal components (67.6%). Cluster Analysis, reduced the fourteen monitoring sites to six

  5. Modificação da microbiota associada às lesões peridentárias da "cara inchada" em bezerros transferidos para área indene

    Directory of Open Access Journals (Sweden)

    Dutra Iveraldo S.

    2000-01-01

    Full Text Available Observações sobre a epizootiologia da "cara inchada" dos bovinos (CI indicam que animais clinicamente positivos se recuperam espontâneamente quando transferidos para área indene. No presente estudo, 13 bovinos com lesões peridentárias progressivas da "cara inchada" foram transferidos para área indene com a finalidade de se verificar a evolução clínica da doença e a composição da microbiota da bolsa peridentária em duas situações distintas: (1 nas lesões progressivas e (2 quando da recuperação clínica. O estudo bacteriológico semi-quantitativo e qualitativo foi realizado tendo como referência a percentagem de Bacteroides pigmentados de negro presentes nos cultivos. Nas lesões progressivas a percentagem média destes microrganismos foi de 71,3%. Após 4 a 7 meses da transferência os animais se recuperaram espontaneamente, observando-se uma melhora na condição nutricional, desaparecimento do abaulamento facial e do odor fétido bucal e cicatrização com epitelização das lesões peridentárias. Na avaliação da composição da micro-biota das bolsas peridentárias dos bezerros quando clinicamente recuperados, este mesmo grupo de micorganismos representou em média 1,7%. Os resultados revelaram a ocorrência de uma predominância de Bacteroides pigmentados de negro nas lesões peridentárias progressivas da "cara inchada"e sua remissão quantitativa percentual após a recuperação clínica dos animais, consubstanciando as evidências de sua natureza infecciosa primária.

  6. Systems biology of bacterial nitrogen fixation: High-throughput technology and its integrative description with constraint-based modeling

    Directory of Open Access Journals (Sweden)

    Resendis-Antonio Osbaldo

    2011-07-01

    Full Text Available Abstract Background Bacterial nitrogen fixation is the biological process by which atmospheric nitrogen is uptaken by bacteroids located in plant root nodules and converted into ammonium through the enzymatic activity of nitrogenase. In practice, this biological process serves as a natural form of fertilization and its optimization has significant implications in sustainable agricultural programs. Currently, the advent of high-throughput technology supplies with valuable data that contribute to understanding the metabolic activity during bacterial nitrogen fixation. This undertaking is not trivial, and the development of computational methods useful in accomplishing an integrative, descriptive and predictive framework is a crucial issue to decoding the principles that regulated the metabolic activity of this biological process. Results In this work we present a systems biology description of the metabolic activity in bacterial nitrogen fixation. This was accomplished by an integrative analysis involving high-throughput data and constraint-based modeling to characterize the metabolic activity in Rhizobium etli bacteroids located at the root nodules of Phaseolus vulgaris (bean plant. Proteome and transcriptome technologies led us to identify 415 proteins and 689 up-regulated genes that orchestrate this biological process. Taking into account these data, we: 1 extended the metabolic reconstruction reported for R. etli; 2 simulated the metabolic activity during symbiotic nitrogen fixation; and 3 evaluated the in silico results in terms of bacteria phenotype. Notably, constraint-based modeling simulated nitrogen fixation activity in such a way that 76.83% of the enzymes and 69.48% of the genes were experimentally justified. Finally, to further assess the predictive scope of the computational model, gene deletion analysis was carried out on nine metabolic enzymes. Our model concluded that an altered metabolic activity on these enzymes induced

  7. Tiered approach for identification of a human fecal pollution source at a recreational beach: case study at Avalon Bay, Catalina Island, California.

    Science.gov (United States)

    Boehm, Alexandria B; Fuhrman, Jed A; Mrse, Robert D; Grant, Stanley B

    2003-02-15

    Recreational marine beaches in California are posted as unfit for swimming when the concentration of fecal indicator bacteria (FIB) exceeds any of seven concentration standards. Finding and mitigating sources of shoreline FIB is complicated by the many potential human and nonhuman sources of these organisms and the complex fate and transport processes that control their concentrations. In this study, a three-tiered approach is used to identify human and nonhuman sources of FIB in Avalon Bay, a popular resort community on Catalina Island in southern California. The first and second tiers utilize standard FIB tests to spatially isolate the FIB signal, to characterize the variability of FIB over a range of temporal scales, and to measure FIB concentrations in potential sources of these organisms. In the third tier, water samples from FIB "hot spots" and sources are tested for human-specific bacteria Bacteroides/Prevotella and enterovirus to determine whether the FIB are from human sewage or from nonhuman sources such as bird feces. FIB in Avalon Bay appear to be from multiple, primarily land-based, sources including bird droppings, contaminated subsurface water, leaking drains, and runoff from street wash-down actvities. Multiple shoreline samples and two subsurface water samples tested positive for human-specific bacteria and enterovirus, suggesting that at least a portion of the FIB contamination is from human sewage.

  8. RNA-stable-isotope probing shows utilization of carbon from inulin by specific bacterial populations in the rat large bowel.

    Science.gov (United States)

    Tannock, Gerald W; Lawley, Blair; Munro, Karen; Sims, Ian M; Lee, Julian; Butts, Christine A; Roy, Nicole

    2014-04-01

    Knowledge of the trophisms that underpin bowel microbiota composition is required in order to understand its complex phylogeny and function. Stable-isotope ((13)C)-labeled inulin was added to the diet of rats on a single occasion in order to detect utilization of inulin-derived substrates by particular members of the cecal microbiota. Cecal digesta from Fibruline-inulin-fed rats was collected prior to (0 h) and at 6, 12, 18 and 24 h following provision of the [(13)C]inulin diet. RNA was extracted from these cecal specimens and fractionated in isopycnic buoyant density gradients in order to detect (13)C-labeled nucleic acid originating in bacterial cells that had metabolized the labeled dietary constituent. RNA extracted from specimens collected after provision of the labeled diet was more dense than 0-h RNA. Sequencing of 16S rRNA genes amplified from cDNA obtained from these fractions showed that Bacteroides uniformis, Blautia glucerasea, Clostridium indolis, and Bifidobacterium animalis were the main users of the (13)C-labeled substrate. Culture-based studies of strains of these bacterial species enabled trophisms associated with inulin and its hydrolysis products to be identified. B. uniformis utilized Fibruline-inulin for growth, whereas the other species used fructo-oligosaccharide and monosaccharides. Thus, RNA-stable-isotope probing (RNA-SIP) provided new information about the use of carbon from inulin in microbiota metabolism.

  9. Effects of New Dietary Fiber from Japanese Apricot (Prunus mume Sieb. et Zucc. on Gut Function and Intestinal Microflora in Adult Mice

    Directory of Open Access Journals (Sweden)

    Nobuki Gato

    2011-03-01

    Full Text Available Much attention has been focused recently on functional foods. Ume, the Japanese name for the apricot of Prunus mume Sieb. et Zucc., is an example of a Japanese traditional functional food. There are, however, few reports on the effects of fiber from this fruit on bowel function. With this objective, we prepared ume fiber to test the hypothesis that it can change gut function and intestinal flora in mice. Mice were fed an ume fiber (UF or cellulose (CF diet (control for 40 days. The fecal weight, fecal lipids, plasma lipids and cecal composition of the microflora were analyzed. The amount of feces was significantly greater in the UF group than in the CF group (p < 0.01. The fecal lipids content (% DW of the feces sampled on the final days of the experiment were significantly greater in the UF group than in the CF group (p < 0.01. Plasma non-esterified fatty acids (NEFA concentrations tended to be lower in the UF compared to the CF group (p = 0.058. Occupation ratios of Bacteroides and Clostridium cluster IV were significantly greater in the cecal flora of the UF group. Our results suggest that ume fiber possesses the fecal lipid excretion effects and feces bulking effects.

  10. 肠道细菌对天然药物代谢的研究进展Ⅱ

    Institute of Scientific and Technical Information of China (English)

    刘明杰; 林琳; 王钊

    2001-01-01

    @@ 3.3 皂苷类化合物 皂苷类化合物大都可以被肠道细菌水解.甘草甜素(Glycyrrhizin,GL)是欧亚甘草(Glycyrrhiza glabra)浸出物的主要组份,可作甜味剂,同时还具有抗病毒、抗炎和固醇类作用.GL在人肠道细菌作用下可从两个途径代谢:主要途径是通过畸形菌体J-37(Bacteroides J-37)和真细菌GLH(Eubacterium sp.GLH)的β-葡糖苷酸酶的作用,代谢生成甘草次酸(18β-glycyrrhetinic acid,GA)[7]:次要途径是先在链球菌LJ-22(Streptococcus LJ-22)的β-D葡糖苷酸酶作用下,GL代谢生成3-葡糖醛酸甘草次酸(18β-glycyrrhetinic acid-3-O-β-D-glucuronide,GAMG),进一步在β-D-葡糖醛酸酶的作用下生成GA[8].

  11. Comparative analysis of bacterial community and antibiotic-resistant strains in different developmental stages of the housefly (Musca domestica).

    Science.gov (United States)

    Wei, Ting; Hu, Jun; Miyanaga, Kazuhiko; Tanji, Yasunori

    2013-02-01

    The housefly (Musca domestica) is an important host for a variety of bacteria, including some pathogenic and antibiotic-resistant strains. To further investigate the relationship between the housefly and the bacteria it harbors, it is necessary to understand the fate of microorganisms during the larval metamorphosis. The major bacterial communities in three developmental stages of the housefly (maggot, pupa, and adult fly) were investigated by a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA genes. The bacteria that were identified using DGGE analysis spanned phyla Proteobacteria, Firmicutes, and Bacteroidetes. Changes in the predominant genera were observed during the housefly development. Bacteroides, Koukoulia, and Schineria were detected in maggots, Neisseria in pupae, and Macrococcus, Lactococcus, and Kurthia in adult flies. Antibiotic-resistant bacteria were screened using a selective medium and tested for antibiotic susceptibility. Most resistant isolates from maggots and pupae were classified as Proteus spp., while those from adult flies were much more diverse and spanned 12 genera. Among 20 tested strains across the three stages, 18 were resistant to at least two antibiotics. Overall, we demonstrated that there are changes in the major bacterial communities and antibiotic-resistant strains as the housefly develops.

  12. Use of bromodeoxyuridine immunocapture to identify psychrotolerant phenanthrene-degrading bacteria in phenanthrene-enriched polluted Baltic Sea sediments

    Energy Technology Data Exchange (ETDEWEB)

    Edlund, A.; Jansson, J.

    2008-05-01

    The aim of this study was to enrich and identify psychrotolerant phenanthrenedegrading bacteria from polluted Baltic Sea sediments. Polyaromatic hydrocarbon (PAH)-contaminated sediments were spiked with phenanthrene and incubated for 2 months in the presence of bromodeoxyuridine that is incorporated into the DNA of replicating cells. The bromodeoxyuridine-incorporated DNA was extracted by immunocapture and analyzed by terminal-restriction fragment length polymorphism and 16S rRNA gene cloning and sequencing to identify bacterial populations that were growing. In addition, degradation genes were quantified in the bromodeoxyuridine-incorporated DNA by real-time PCR. Phenanthrene concentrations decreased after 2 months of incubation in the phenanthrene-enriched sediments and this reduction correlated to increases in copy numbers of xylE and phnAc dioxygenase genes. Representatives of Exiguobacterium, Schewanella,Methylomonas, Pseudomonas, Bacteroides and an uncultured Deltaproteobacterium and a Gammaproteobacterium dominated the growing community in the phenanthrene spiked sediments. Isolates that were closely related to three of these bacteria (two pseudomonads and an Exiguobacterium sp.) could reduce phenanthrene concentrations in pure cultures and they all harbored phnAc dioxygenase genes. These results confirm that this combination of culture-based and molecular approaches was useful for identification of actively growing bacterial species with a high potential for phenanthrene degradation.

  13. Redundant Innate and Adaptive Sources of IL17 Production Drive Colon Tumorigenesis.

    Science.gov (United States)

    Housseau, Franck; Wu, Shaoguang; Wick, Elizabeth C; Fan, Hongni; Wu, Xinqun; Llosa, Nicolas J; Smith, Kellie N; Tam, Ada; Ganguly, Sudipto; Wanyiri, Jane W; Iyadorai, Thevambiga; Malik, Ausama A; Roslani, April C; Vadivelu, Jamunarani S; Van Meerbeke, Sara; Huso, David L; Pardoll, Drew M; Sears, Cynthia L

    2016-04-15

    IL17-producing Th17 cells, generated through a STAT3-dependent mechanism, have been shown to promote carcinogenesis in many systems, including microbe-driven colon cancer. Additional sources of IL17, such as γδ T cells, become available under inflammatory conditions, but their contributions to cancer development are unclear. In this study, we modeled Th17-driven colon tumorigenesis by colonizing Min(Ap) (c+/-) mice with the human gut bacterium, enterotoxigenic Bacteroides fragilis (ETBF), to investigate the link between inflammation and colorectal cancer. We found that ablating Th17 cells by knocking out Stat3 in CD4(+) T cells delayed tumorigenesis, but failed to suppress the eventual formation of colonic tumors. However, IL17 blockade significantly attenuated tumor formation, indicating a critical requirement for IL17 in tumorigenesis, but from a source other than Th17 cells. Notably, genetic ablation of γδ T cells in ETBF-colonized Th17-deficient Min mice prevented the late emergence of colonic tumors. Taken together, these findings support a redundant role for adaptive Th17 cell- and innate γδT17 cell-derived IL17 in bacteria-induced colon carcinogenesis, stressing the importance of therapeutically targeting the cytokine itself rather than its cellular sources. Cancer Res; 76(8); 2115-24. ©2016 AACR.

  14. Phylogenetic analysis of anaerobic psychrophilic enrichment cultures obtained from a greenland glacier ice core

    Science.gov (United States)

    Sheridan, Peter P.; Miteva, Vanya I.; Brenchley, Jean E.

    2003-01-01

    The examination of microorganisms in glacial ice cores allows the phylogenetic relationships of organisms frozen for thousands of years to be compared with those of current isolates. We developed a method for aseptically sampling a sediment-containing portion of a Greenland ice core that had remained at -9 degrees C for over 100,000 years. Epifluorescence microscopy and flow cytometry results showed that the ice sample contained over 6 x 10(7) cells/ml. Anaerobic enrichment cultures inoculated with melted ice were grown and maintained at -2 degrees C. Genomic DNA extracted from these enrichments was used for the PCR amplification of 16S rRNA genes with bacterial and archaeal primers and the preparation of clone libraries. Approximately 60 bacterial inserts were screened by restriction endonuclease analysis and grouped into 27 unique restriction fragment length polymorphism types, and 24 representative sequences were compared phylogenetically. Diverse sequences representing major phylogenetic groups including alpha, beta, and gamma Proteobacteria as well as relatives of the Thermus, Bacteroides, Eubacterium, and Clostridium groups were found. Sixteen clone sequences were closely related to those from known organisms, with four possibly representing new species. Seven sequences may reflect new genera and were most closely related to sequences obtained only by PCR amplification. One sequence was over 12% distant from its closest relative and may represent a novel order or family. These results show that phylogenetically diverse microorganisms have remained viable within the Greenland ice core for at least 100,000 years.

  15. Molecular detection of marine bacterial populations on beaches contaminated by the Nakhodka tanker oil-spill accident

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Y.; Kishira, H.; Syutsubo, K.; Harayama, S.

    2001-04-01

    In January 1997, the tanker Nakhodka sank in the Japan Sea, and more than 5000 tons of heavy oil leaked. The released oil contaminated more than 500 km of the coastline, and some still remained even by June 1999. To investigate the long-term influence of the Nakhodka oil spill on marine bacterial populations, sea water and residual oil were sampled from the oil-contaminated zones 10, 18, 22 and 29 months after the accident, and the bacterial populations in these samples were analysed by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA fragments. The dominant DGGE bands were sequenced, and the sequences were compared with those in DNA sequence libraries. Most of the bacteria in the sea water samples were classified as the Cytophaga-Flavobacterium-Bacteroides phylum, {alpha}-Proteobacteria or cyanobacteria. The bacteria detected in the oil paste samples were different from those detected in the sea water samples; they were types related to hydrocarbon degraders, exemplified by strains closely related to Sphingomonas subarctica and Alcanivorax borkumensis. The sizes of the major bacterial populations in the oil paste samples ranged from 3.4 x 10{sup 5} to 1.6 x 10{sup 6} bacteria per gram of oil paste, these low numbers explaining the slow rate of natural attenuation. (Author)

  16. Molecular detection of marine bacterial populations on beaches contaminated by the Nakhodka tanker oil-spill accident.

    Science.gov (United States)

    Kasai, Y; Kishira, H; Syutsubo, K; Harayama, S

    2001-04-01

    In January 1997, the tanker Nakhodka sank in the Japan Sea, and more than 5000 tons of heavy oil leaked. The released oil contaminated more than 500 km of the coastline, and some still remained even by June 1999. To investigate the long-term influence of the Nakhodka oil spill on marine bacterial populations, sea water and residual oil were sampled from the oil-contaminated zones 10, 18, 22 and 29 months after the accident, and the bacterial populations in these samples were analysed by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA fragments. The dominant DGGE bands were sequenced, and the sequences were compared with those in DNA sequence libraries. Most of the bacteria in the sea water samples were classified as the Cytophaga-Flavobacterium-Bacteroides phylum, alpha-Proteobacteria or cyanobacteria. The bacteria detected in the oil paste samples were different from those detected in the sea water samples; they were types related to hydrocarbon degraders, exemplified by strains closely related to Sphingomonas subarctica and Alcanivorax borkumensis. The sizes of the major bacterial populations in the oil paste samples ranged from 3.4 x 10(5) to 1.6 x 10(6) bacteria per gram of oil paste, these low numbers explaining the slow rate of natural attenuation.

  17. A case of Goodpasture syndrome positive for anti-GBM antibody and MPO-ANCA complicated by a variety of serious infections.

    Science.gov (United States)

    Sakoda, C; Kusaba, T; Adachi, T; Sonomura, K; Kimura, T; Nakayama, M; Kishimoto, N; Nakagawa, H; Okigaki, M; Hatta, T; Matsubara, H; Mori, Y

    2011-04-01

    A 62-year-old female was admitted to our hospital for investigation of acute progressive renal insufficiency and a systemic inflammatory reaction, despite treatment with several antibiotics. Laboratory data revealed severe renal insufficiency and positive titers for the myeloperoxidase anti-neutrophil cytoplasmic and anti-glomerular basement membrane antibodies. The deterioration of her general status did not allow us to perform the renal biopsy. Although corticosteroid therapy, hemodialysis, and plasma exchange were concomitantly initiated, pulmonary hemorrhage occurred several days after admission. Mechanical ventilation support was provided and continuous hemodiafiltration was carried out, following which the respiratory failure improved immediately. However, she developed clinical depression and suicidal behavior under the intensive therapy. Therefore, plasma exchange was discontinued and corticosteroid was tapered as quickly as possible. Four months after admission, platelet transfusion and short-term mechanical ventilation support improved the pulmonary hemorrhage; however, her mental status deteriorated despite psychiatric consultation and treatment with a tranquilizer. Thereafter, severe and serious systemic infection due to various pathogens including Staphylococcus aureus, Cytomegalovirus, Pneumocystis jiroveci, Pseudomonas aeruginosa, and Bacteroides recurred, and she died from systemic invasive aspergillosis (IA). We suspected severe immunosuppression caused by various factors, such as predonisolone administration, chronic renal failure on maintenance hemodialysis, depression, and malnutrition due to chronic inflammation and granulocytopenia as a side effect of ganciclovir. When treating rapidly progressive glomerulonephritis, immunosuppressive status should be carefully monitored regarding not only the dosage of therapeutic regimen but also the mental health status and nutrition of the patient.

  18. Accurate genome relative abundance estimation based on shotgun metagenomic reads.

    Directory of Open Access Journals (Sweden)

    Li C Xia

    Full Text Available Accurate estimation of microbial community composition based on metagenomic sequencing data is fundamental for subsequent metagenomics analysis. Prevalent estimation methods are mainly based on directly summarizing alignment results or its variants; often result in biased and/or unstable estimates. We have developed a unified probabilistic framework (named GRAMMy by explicitly modeling read assignment ambiguities, genome size biases and read distributions along the genomes. Maximum likelihood method is employed to compute Genome Relative Abundance of microbial communities using the Mixture Model theory (GRAMMy. GRAMMy has been demonstrated to give estimates that are accurate and robust across both simulated and real read benchmark datasets. We applied GRAMMy to a collection of 34 metagenomic read sets from four metagenomics projects and identified 99 frequent species (minimally 0.5% abundant in at least 50% of the data-sets in the human gut samples. Our results show substantial improvements over previous studies, such as adjusting the over-estimated abundance for Bacteroides species for human gut samples, by providing a new reference-based strategy for metagenomic sample comparisons. GRAMMy can be used flexibly with many read assignment tools (mapping, alignment or composition-based even with low-sensitivity mapping results from huge short-read datasets. It will be increasingly useful as an accurate and robust tool for abundance estimation with the growing size of read sets and the expanding database of reference genomes.

  19. Development and application of a multilocus sequence analysis method for the identification of genotypes within genus Bradyrhizobium and for establishing nodule occupancy of soybean (Glycine max L. Merr).

    Science.gov (United States)

    van Berkum, Peter; Elia, Patrick; Song, Qijian; Eardly, Bertrand D

    2012-03-01

    A multilocus sequence typing (MLST) method based on allelic variation of seven chromosomal loci was developed for characterizing genotypes (GT) within the genus Bradyrhizobium. With the method, 29 distinct multilocus GT were identified among 190 culture collection soybean strains. The occupancy of 347 nodules taken from uninoculated field-grown soybean plants also was determined. The bacteroid GT were either the same as or were closely related to GT identified among strains in the culture collection. Double-nodule occupancy estimates of 2.9% were much lower than values published based on serology. Of the 347 nodules examined, 337 and 10 were occupied by Bradyrhizobium japonicum and B. elkanii, respectively. The collection strains within the species B. japonicum and B. elkaniialso were compared with Bradyrhizobium cultures from other legumes. In many cases, the observed GT varied more according to their geographic origin than by their trap hosts of isolation. In other cases, there were no apparent relationships with either the legume or geographic source. The MLST method that was developed should be a useful tool in determining the influence of geographic location, temperature, season, soil type, and host plant cultivar on the distribution of GT of Bradyrhizobium spp.

  20. Cell-free supernatants from probiotic Lactobacillus casei and Lactobacillus rhamnosus GG decrease colon cancer cell invasion in vitro.

    Science.gov (United States)

    Escamilla, Juanita; Lane, Michelle A; Maitin, Vatsala

    2012-08-01

    Probiotics have been shown to have a preventative role in colorectal carcinogenesis but research concerning their prophylactic potential in the later stages of colorectal cancer, specifically metastasis is limited. This study explored the potential of cell-free supernatants (CFS) from 2 probiotic Lactobacillus sp., Lactobacillus casei and Lactobacillus rhamnosus GG, to inhibit colon cancer cell invasion by influencing matrix metalloproteinase-9 (MMP-9) activity and levels of the tight junction protein zona occludens-1 (ZO-1) in cultured metastatic human colorectal carcinoma cells. HCT-116 cells were treated with CFS from L. casei, L. rhamnosus, or Bacteroides thetaiotaomicron (a gut commensal); or with uninoculated bacterial growth media. Treatment with CFS from both Lactobacillus sp. decreased colorectal cell invasion but treatment with CFS from B. thetaiotaomicron did not. CFS from both Lactobacillus sp. decreased MMP-9 and increased ZO-1 protein levels. L. rhamnosus CFS also lowered MMP-9 activity. To begin elucidating the secreted bacterial factor conveying these responses, Lactobacillus sp. CFS were fractionated into defined molecular weight ranges and cell invasion assessed. Fractionation revealed that the inhibitory activity was contained primarily in the >100 kDa and 50-100 kDa fractions, suggesting the inhibitory compound may be a macromolecule such as a protein, nucleic acid, or a polysaccharide.

  1. Limited beneficial effects of piceatannol supplementation on obesity complications in the obese Zucker rat: gut microbiota, metabolic, endocrine, and cardiac aspects.

    Science.gov (United States)

    Hijona, E; Aguirre, L; Pérez-Matute, P; Villanueva-Millán, M J; Mosqueda-Solis, A; Hasnaoui, M; Nepveu, F; Senard, J M; Bujanda, L; Aldámiz-Echevarría, L; Llarena, M; Andrade, F; Perio, P; Leboulanger, F; Hijona, L; Arbones-Mainar, J M; Portillo, M P; Carpéné, C

    2016-09-01

    Resveratrol is beneficial in obese and diabetic rodents. However, its low bioavailability raises questions about its therapeutic relevance for treating or preventing obesity complications. In this context, many related natural polyphenols are being tested for their putative antidiabetic and anti-obesity effects. This prompted us to study the influence of piceatannol, a polyhydroxylated stilbene, on the prevention of obesity complications in Zucker obese rats. A 6-week supplementation was followed by the determination of various markers in plasma, liver, adipose tissue and heart, together with a large-scale analysis of gut microbiota composition. When given in doses of 15 or 45 mg/kg body weight/day, piceatannol did not reduce either hyperphagia or fat accumulation. It did not modify the profusion of the most abundant phyla in gut, though slight changes were observed in the abundance of several Lactobacillus, Clostridium, and Bacteroides species belonging to Firmicutes and Bacteroidetes. This was accompanied by a tendency to reduce plasma lipopolysaccharides by 30 %, and by a decrease of circulating non-esterified fatty acids, LDL-cholesterol, and lactate. While piceatannol tended to improve lipid handling, it did not mitigate hyperinsulinemia and cardiac hypertrophy. However, it increased cardiac expression of ephrin-B1, a membrane protein that contributes to maintaining cardiomyocyte architecture. Lastly, ascorbyl radical plasma levels and hydrogen peroxide release by adipose tissue were similar in control and treated groups. Thus, piceatannol did not exhibit strong slimming capacities but did limit several obesity complications.

  2. Functional diversity of five homologous Cu+-ATPases present in Sinorhizobium meliloti.

    Science.gov (United States)

    Patel, Sarju J; Padilla-Benavides, Teresita; Collins, Jessica M; Argüello, José M

    2014-06-01

    Copper is an important element in host-microbe interactions, acting both as a catalyst in enzymes and as a potential toxin. Cu(+)-ATPases drive cytoplasmic Cu(+) efflux and protect bacteria against metal overload. Many pathogenic and symbiotic bacteria contain multiple Cu(+)-ATPase genes within particular genetic environments, suggesting alternative roles for each resulting protein. This hypothesis was tested by characterizing five homologous Cu(+)-ATPases present in the symbiotic organism Sinorhizobium meliloti. Mutation of each gene led to different phenotypes and abnormal nodule development in the alfalfa host. Distinct responses were detected in free-living S. meliloti mutant strains exposed to metal and redox stresses. Differential gene expression was detected under Cu(+), oxygen or nitrosative stress. These observations suggest that CopA1a maintains the cytoplasmic Cu(+) quota and its expression is controlled by Cu(+) levels. CopA1b is also regulated by Cu(+) concentrations and is required during symbiosis for bacteroid maturation. CopA2-like proteins, FixI1 and FixI2, are necessary for the assembly of two different cytochrome c oxidases at different stages of bacterial life. CopA3 is a phylogenetically distinct Cu(+)-ATPase that does not contribute to Cu(+) tolerance. It is regulated by redox stress and required during symbiosis. We postulated a model where non-redundant homologous Cu(+)-ATPases, operating under distinct regulation, transport Cu(+) to different target proteins.

  3. Transcriptional regulator LsrB of Sinorhizobium meliloti positively regulates the expression of genes involved in lipopolysaccharide biosynthesis.

    Science.gov (United States)

    Tang, Guirong; Wang, Ying; Luo, Li

    2014-09-01

    Rhizobia induce nitrogen-fixing nodules on host legumes, which is important in agriculture and ecology. Lipopolysaccharide (LPS) produced by rhizobia is required for infection or bacteroid survival in host cells. Genes required for LPS biosynthesis have been identified in several Rhizobium species. However, the regulation of their expression is not well understood. Here, Sinorhizobium meliloti LsrB, a member of the LysR family of transcriptional regulators, was found to be involved in LPS biosynthesis by positively regulating the expression of the lrp3-lpsCDE operon. An lsrB in-frame deletion mutant displayed growth deficiency, sensitivity to the detergent sodium dodecyl sulfate, and acidic pH compared to the parent strain. This mutant produced slightly less LPS due to lower expression of the lrp3 operon. Analysis of the transcriptional start sites of the lrp3 and lpsCDE gene suggested that they constitute one operon. The expression of lsrB was positively autoregulated. The promoter region of lrp3 was specifically precipitated by anti-LsrB antibodies in vivo. The promoter DNA fragment containing TN11A motifs was bound by the purified LsrB protein in vitro. These new findings suggest that S. meliloti LsrB is associated with LPS biosynthesis, which is required for symbiotic nitrogen fixation on some ecotypes of alfalfa plants.

  4. Comparison of Ribosomal Protein of Alfalfa Rhizobia ( Sinorhizobium meliloti ) under Self-Growing and Symbiotic States%苜蓿根瘤菌自生与共生状态下核糖体蛋白的比较

    Institute of Scientific and Technical Information of China (English)

    谢荣; 刘望夷; 朱家壁; 俞冠翘

    2006-01-01

    苜蓿根瘤菌在与宿主植物建立共生关系的过程中,以自生状态进入宿主植物细胞,经过分化发育转变为共生状态的类菌体(Bacteroid).由于生存环境发生了变化,类菌体在形态、结构和功能方面都产生了很大的改变,其中最为明显的改变是类菌体获得了共生固氮的能力.此时,类菌体中许多与共生相关的基因被激活,蛋白的表达量显著增加.为了探明这种改变是否与合成蛋白质的细胞器-核糖体有关,比较分析了苜蓿根瘤菌在自生和共生状态下核糖体蛋白的表达谱.蛋白质双向电泳结果显示二者之间没有明显的差别,说明类菌体的分化发育过程中核糖体蛋白的形成没有改变.

  5. Sinorhizobium meliloti CpdR1 is critical for co-ordinating cell cycle progression and the symbiotic chronic infection.

    Science.gov (United States)

    Kobayashi, Hajime; De Nisco, Nicole J; Chien, Peter; Simmons, Lyle A; Walker, Graham C

    2009-08-01

    ATP-driven proteolysis plays a major role in regulating the bacterial cell cycle, development and stress responses. In the nitro -fixing symbiosis with host plants, Sinorhizobium meliloti undergoes a profound cellular differentiation, including endoreduplication of the ome. The regulatory mechanisms governing the alterations of the S. meliloti cell cycle in planta are largely unknown. Here, we report the characterization of two cpdR homologues, cpdR1 and cpdR2, of S. meliloti that encode single-domain response regulators. In Caulobacter crescentus, CpdR controls the polar localization of the ClpXP protease, thereby mediating the regulated proteolysis of key protein(s), such as CtrA, involved in cell cycle progression. The S. meliloti cpdR1-null mutant can invade the host cytoplasm, however, the intracellular bacteria are unable to differentiate into bacteroids. We show that S. meliloti CpdR1 has a polar localization pattern and a role in ClpX positioning similar to C. crescentus CpdR, suggesting a conserved function of CpdR proteins among alpha-proteobacteria. However, in S. meliloti, free-living cells of the cpdR1-null mutant show a striking morphology of irregular coccoids and aberrant DNA replication. Thus, we demonstrate that CpdR1 mediates the co-ordination of cell cycle events, which are critical for both the free-living cell division and the differentiation required for the chronic intracellular infection.

  6. The DivJ, CbrA and PleC system controls DivK phosphorylation and symbiosis in Sinorhizobium meliloti.

    Science.gov (United States)

    Pini, Francesco; Frage, Benjamin; Ferri, Lorenzo; De Nisco, Nicole J; Mohapatra, Saswat S; Taddei, Lucilla; Fioravanti, Antonella; Dewitte, Frederique; Galardini, Marco; Brilli, Matteo; Villeret, Vincent; Bazzicalupo, Marco; Mengoni, Alessio; Walker, Graham C; Becker, Anke; Biondi, Emanuele G

    2013-10-01

    Sinorhizobium meliloti is a soil bacterium that invades the root nodules it induces on Medicago sativa, whereupon it undergoes an alteration of its cell cycle and differentiates into nitrogen-fixing, elongated and polyploid bacteroid with higher membrane permeability. In Caulobacter crescentus, a related alphaproteobacterium, the principal cell cycle regulator, CtrA, is inhibited by the phosphorylated response regulator DivK. The phosphorylation of DivK depends on the histidine kinase DivJ, while PleC is the principal phosphatase for DivK. Despite the importance of the DivJ in C. crescentus, the mechanistic role of this kinase has never been elucidated in other Alphaproteobacteria. We show here that the histidine kinases DivJ together with CbrA and PleC participate in a complex phosphorylation system of the essential response regulator DivK in S. meliloti. In particular, DivJ and CbrA are involved in DivK phosphorylation and in turn CtrA inactivation, thereby controlling correct cell cycle progression and the integrity of the cell envelope. In contrast, the essential PleC presumably acts as a phosphatase of DivK. Interestingly, we found that a DivJ mutant is able to elicit nodules and enter plant cells, but fails to establish an effective symbiosis suggesting that proper envelope and/or low CtrA levels are required for symbiosis.

  7. Nitric oxide is formed in Medicago truncatula-Sinorhizobium meliloti functional nodules.

    Science.gov (United States)

    Baudouin, Emmanuel; Pieuchot, Laurent; Engler, Gilbert; Pauly, Nicolas; Puppo, Alain

    2006-09-01

    Nitric oxide (NO) has recently gained interest as a major signaling molecule during plant development and response to environmental cues. Its role is particularly crucial for plant-pathogen interactions, during which it participates in the control of plant defense response and resistance. Indication for the presence of NO during symbiotic interactions has also been reported. Here, we defined when and where NO is produced during Medicago truncatula-Sinorhizobium meliloti symbiosis. Using the NO-specific fluorescent probe 4,5-diaminofluorescein diacetate, NO production was detected by confocal microscopy in functional nodules. NO production was localized in the bacteroid-containing cells of the nodule fixation zone. The infection of Medicago roots with bacterial strains impaired in nitrogenase or nitrite reductase activities lead to the formation of nodules with an unaffected NO level, indicating that neither nitrogen fixation nor denitrification pathways are required for NO production. On the other hand, the NO synthase inhibitor N-methyl-L-arginine impaired NO detection, suggesting that a NO synthase may participate to NO production in nodules. These data indicate that a NO production occurs in functional nodules. The location of such a production in fully metabolically active cells raises the hypothesis of a new function for NO during this interaction unrelated to defense and cell-death activation.

  8. Microbial community structure in major habitats above 6000 m on Mount Everest

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Bacterial abundance in surface snow between 6600 and 8000 m a.s.l. On the northern slope of Mt. Everest was investigated by flow cytometry. Bacterial diversity in serac ice at 6000 m a.s.l., glacier meltwater at 6350 m, and surface snow at 6600 m a.s.l. Was examined by constructing a 16S rRNA gene clone library. Bacterial abundance in snow was higher than that in the Antarctic but similar to other mountain regions in the world. Bacterial abundance in surface snow increased with altitude but showed no correlation with chemical parameters. Bacteria in the cryosphere on Mt. Everest were closely related to those isolated from soil, aquatic environments, plants, animals, humans and other frozen environments. Bacterial community structures in major habitats above 6000 m were variable. The Cytophaga-Flavobacterium-Bacteroides (CFB) group absolutely dominated in glacial meltwater, while β-Proteobacteria and the CFB group dominated in serac ice, and β-Proteobacteria and Actinobacteria dominated in surface snow. The remarkable differences among the habitats were most likely due to the bacterial post-deposition changes during acclimation processes.

  9. Bacteremia due to anaerobic bacteria: epidemiology in a northern Bari Hospital, Italy

    Directory of Open Access Journals (Sweden)

    Maria Antonietta Distasi

    2015-06-01

    Full Text Available Background. Anaerobic bacteria are part of the commensal bacterial flora of skin and mucosae. Iatrogenic and pathological conditions altering this commensal relationship cause life-threatening diseases. Materials and Methods. We analysed the blood cultures sent to the microbiology of our hospital between 2008 and the first quarter of 2013 to measure the frequency of bacteraemia caused by anaerobia. We examined 3138 vials of blood cultures for anaerobia, inoculated following in-house standard procedures. The colonies grown in absence of air were subjected to biochemical analysis. The MICs of metronidazole for 23 of the 26 organisms was tested. Results. Twelve bacteria of the Bacteroides genus were identified, 9 Propionibacterium acnes, 1 Peptosctreptococcus micros, 1 Lactobacillus acidophilus, 1 Clostridium perfringens, 1 Prevotella oralis, 1 Eubacterium lentum. Conclusions. The analysis of the results suggests that the incidence of cultures positive to anaerobia was constant across the years. We note that advanced age, altered mucocutaneous tropism, alterations to the oral and intestinal bacterial flora intensify the risk of anaerobial pathogenicity. The analysis of the metronidazole-determined MIC suggests that the intestinal anaerobic flora responds well to therapy and prophylaxis with Metronidazole, while the anaerobic bacteria residing on skin and other mucosae are resistant. It is however hard to determine the clinical impact of anaerobic bacteremiae and their effect on the outcome of the patient, due to the scarcity of available clinical data.

  10. Algae-bacteria association inferred by 16S rDNA similarity in established microalgae cultures.

    Science.gov (United States)

    Schwenk, Dagmar; Nohynek, Liisa; Rischer, Heiko

    2014-06-01

    Forty cultivable, visually distinct bacterial cultures were isolated from four Baltic microalgal cultures Chlorella pyrenoidosa, Scenedesmus obliquus, Isochrysis sp., and Nitzschia microcephala, which have been maintained for several years in the laboratory. Bacterial isolates were characterized with respect to morphology, antibiotic susceptibility, and 16S ribosomal DNA sequence. A total of 17 unique bacterial strains, almost all belonging to one of three families, Rhodobacteraceae, Rhizobiaceae, and Erythrobacteraceae, were subsequently isolated. The majority of isolated bacteria belong to Rhodobacteraceae. Literature review revealed that close relatives of the bacteria isolated in this study are not only often found in marine environments associated with algae, but also in lakes, sediments, and soil. Some of them had been shown to interact with organisms in their surroundings. A Basic Local Alignment Search Tool study indicated that especially bacteria isolated from the Isochrysis sp. culture were highly similar to microalgae-associated bacteria. Two of those isolates, I1 and I6, belong to the Cytophaga-Flavobacterium-Bacteroides phylum, members of which are known to occur in close communities with microalgae. An UniFrac analysis revealed that the bacterial community of Isochrysis sp. significantly differs from the other three communities.

  11. Dietary history contributes to enterotype-like clustering and functional metagenomic content in the intestinal microbiome of wild mice.

    Science.gov (United States)

    Wang, Jun; Linnenbrink, Miriam; Künzel, Sven; Fernandes, Ricardo; Nadeau, Marie-Josée; Rosenstiel, Philip; Baines, John F

    2014-07-01

    Understanding the origins of gut microbial community structure is critical for the identification and interpretation of potential fitness-related traits for the host. The presence of community clusters characterized by differences in the abundance of signature taxa, referred to as enterotypes, is a debated concept first reported in humans and later extended to other mammalian hosts. In this study, we provide a thorough assessment of their existence in wild house mice using a panel of evaluation criteria. We identify support for two clusters that are compositionally similar to clusters identified in humans, chimpanzees, and laboratory mice, characterized by differences in Bacteroides, Robinsoniella, and unclassified genera belonging to the family Lachnospiraceae. To further evaluate these clusters, we (i) monitored community changes associated with moving mice from the natural to a laboratory environment, (ii) performed functional metagenomic sequencing, and (iii) subjected wild-caught samples to stable isotope analysis to reconstruct dietary patterns. This process reveals differences in the proportions of genes involved in carbohydrate versus protein metabolism in the functional metagenome, as well as differences in plant- versus meat-derived food sources between clusters. In conjunction with wild-caught mice quickly changing their enterotype classification upon transfer to a standard laboratory chow diet, these results provide strong evidence that dietary history contributes to the presence of enterotype-like clustering in wild mice.

  12. Comprehensive Survey of Intestinal Microbiota Changes in Offspring of Human Microbiota-Associated Mice

    Science.gov (United States)

    von Klitzing, Eliane; Öz, Fulya; Ekmekciu, Ira; Escher, Ulrike; Bereswill, Stefan; Heimesaat, Markus M.

    2017-01-01

    Secondary abiotic mice generated by broad-spectrum antibiotic treatment provide a valuable tool for association studies with microbiota derived from different vertebrate hosts. We here generated human microbiota-associated (hma) mice by human fecal microbiota transplantation of secondary abiotic mice and performed a comprehensive survey of the intestinal microbiota dynamics in offspring of hma mice over 18 weeks following weaning as compared to their mothers applying both cultural and molecular methods. Mice were maintained under standard hygienic conditions with open cages, handled under aseptic conditions, and fed autoclaved chow and water. Within 1 week post weaning, fecal loads of commensal enterobacteria and enterococci had decreased, whereas obligate anaerobic bacteria such as Bacteroides/Prevotella species and clostridia were stably colonizing the intestines of hma offspring at high loads. Lactobacilli numbers were successively increasing until 18 weeks post weaning in both hma offspring and mothers, whereas by then, bifidobacteria were virtually undetectable in the former only. Interestingly, fecal lactobacilli and bifidobacteria were higher in mothers as compared to their offspring at 5 and 18 weeks post weaning. We conclude that the intestinal microbiota composition changes in offspring of hma mice, but also their mothers over time particularly affecting aerobic and microaerobic species. PMID:28386472

  13. crinkle, a novel symbiotic mutant that affects the infection thread growth and alters the root hair, trichome, and seed development in Lotus japonicus.

    Science.gov (United States)

    Tansengco, Myra L; Hayashi, Makoto; Kawaguchi, Masayoshi; Imaizumi-Anraku, Haruko; Murooka, Yoshikatsu

    2003-03-01

    To elucidate the mechanisms involved in Rhizobium-legume symbiosis, we examined a novel symbiotic mutant, crinkle (Ljsym79), from the model legume Lotus japonicus. On nitrogen-starved medium, crinkle mutants inoculated with the symbiont bacterium Mesorhizobium loti MAFF 303099 showed severe nitrogen deficiency symptoms. This mutant was characterized by the production of many bumps and small, white, uninfected nodule-like structures. Few nodules were pale-pink and irregularly shaped with nitrogen-fixing bacteroids and expressing leghemoglobin mRNA. Morphological analysis of infected roots showed that nodulation in crinkle mutants is blocked at the stage of the infection process. Confocal microscopy and histological examination of crinkle nodules revealed that infection threads were arrested upon penetrating the epidermal cells. Starch accumulation in uninfected cells and undeveloped vascular bundles were also noted in crinkle nodules. Results suggest that the Crinkle gene controls the infection process that is crucial during the early stage of nodule organogenesis. Aside from the symbiotic phenotypes, crinkle mutants also developed morphological alterations, such as crinkly or wavy trichomes, short seedpods with aborted embryos, and swollen root hairs. crinkle is therefore required for symbiotic nodule development and for other aspects of plant development.

  14. Structure-guided functional characterization of DUF1460 reveals a highly specific NlpC/P60 amidase family.

    Science.gov (United States)

    Xu, Qingping; Mengin-Lecreulx, Dominique; Patin, Delphine; Grant, Joanna C; Chiu, Hsiu-Ju; Jaroszewski, Lukasz; Knuth, Mark W; Godzik, Adam; Lesley, Scott A; Elsliger, Marc-André; Deacon, Ashley M; Wilson, Ian A

    2014-12-02

    GlcNAc-1,6-anhydro-MurNAc-tetrapeptide is a major peptidoglycan degradation intermediate and a cytotoxin. It is generated by lytic transglycosylases and further degraded and recycled by various enzymes. We have identified and characterized a highly specific N-acetylmuramoyl-L-alanine amidase (AmiA) from Bacteroides uniformis, a member of the DUF1460 protein family, that hydrolyzes GlcNAc-1,6-anhydro-MurNAc-peptide into disaccharide and stem peptide. The high-resolution apo structure at 1.15 Å resolution shows that AmiA is related to NlpC/P60 γ-D-Glu-meso-diaminopimelic acid amidases and shares a common catalytic core and cysteine peptidase-like active site. AmiA has evolved structural adaptations that reconfigure the substrate recognition site. The preferred substrates for AmiA were predicted in silico based on structural and bioinformatics data, and subsequently were characterized experimentally. Further crystal structures of AmiA in complexes with GlcNAc-1,6-anhydro-MurNAc and GlcNAc have enabled us to elucidate substrate recognition and specificity. DUF1460 is highly conserved in structure and defines another amidase family.

  15. In vitro fermentation of B-GOS: impact on faecal bacterial populations and metabolic activity in autistic and non-autistic children.

    Science.gov (United States)

    Grimaldi, Roberta; Cela, Drinalda; Swann, Jonathan R; Vulevic, Jelena; Gibson, Glenn R; Tzortzis, George; Costabile, Adele

    2017-02-01

    Children with autism spectrum disorders (ASD) often suffer gastrointestinal problems consistent with imbalances in the gut microbial population. Treatment with antibiotics or pro/prebiotics has been postulated to regulate microbiota and improve gut symptoms, but there is a lack of evidence for such approaches, especially for prebiotics. This study assessed the influence of a prebiotic galactooligosaccharide (B-GOS) on gut microbial ecology and metabolic function using faecal samples from autistic and non-autistic children in an in vitro gut model system. Bacteriology was analysed using flow cytometry combined with fluorescence in situ hybridization and metabolic activity by HPLC and (1)H-NMR. Consistent with previous studies, the microbiota of children with ASD contained a higher number of Clostridium spp. and a lower number of bifidobacteria compared with non-autistic children. B-GOS administration significantly increased bifidobacterial populations in each compartment of the models, both with autistic and non-autistic-derived samples, and lactobacilli in the final vessel of non-autistic models. In addition, changes in other bacterial population have been seen in particular for Clostridium, Rosburia, Bacteroides, Atopobium, Faecalibacterium prausnitzii, Sutterella spp. and Veillonellaceae. Furthermore, the addition of B-GOS to the models significantly altered short-chain fatty acid production in both groups, and increased ethanol and lactate in autistic children.

  16. Dairy and plant based food intakes are associated with altered faecal microbiota in 2 to 3 year old Australian children

    Science.gov (United States)

    Smith-Brown, P.; Morrison, M.; Krause, L.; Davies, P. S. W.

    2016-01-01

    The first 1000 days (conception to 24 months) is when gut microbiota composition and eating patterns are established, and a critical period influencing lifelong health. The aim of this study is to examine the associations between food intakes and microbiota composition at the end of this period. Diet was quantified for 37 well-nourished Australian children aged between 2 to 3 years by using a food frequency questionnaire and 24 hr recalls. Both dairy and plant-based (fruit, vegetables, soy, pulses and nuts) food intakes were associated with distinct microbiota profiles. Dairy intake was positively associated with the Firmicutes:Bacteroidetes ratio, and in particular Erysipelatoclostridium spp., but negatively associated with species richness and diversity. Vegetable intake was positively associated with the relative abundance of the Lachnospira genus, while soy, pulse and nut intake was positively associated with the relative abundance of bacteria related to Bacteroides xylanisolvens. Fruit intake, especially apples and pears, were negatively associated with the relative abundance of bacteria related to Ruminococcus gnavus. In this cohort of young children dairy and plant based food intakes were found to be associated with altered microbiota composition. Further exploration is needed to elucidate the effect of these dietary and microbial differences on host phenotype. PMID:27694811

  17. Intake of Meat Proteins Substantially Increased the Relative Abundance of Genus Lactobacillus in Rat Feces.

    Directory of Open Access Journals (Sweden)

    Yingying Zhu

    Full Text Available Diet has been shown to have a critical influence on gut bacteria and host health, and high levels of red meat in diet have been shown to increase colonic DNA damage and thus be harmful to gut health. However, previous studies focused more on the effects of meat than of meat proteins. In order to investigate whether intake of meat proteins affects the composition and metabolic activities of gut microbiota, feces were collected from growing rats that were fed with either meat proteins (from beef, pork or fish or non-meat proteins (casein or soy for 14 days. The resulting composition of gut microbiota was profiled by sequencing the V4-V5 region of the 16S ribosomal RNA genes and the short chain fatty acids (SCFAs were analyzed using gas chromatography. The composition of gut microbiota and SCFA levels were significantly different between the five diet groups. At a recommended dose of 20% protein in the diet, meat protein-fed rats had a higher relative abundance of the beneficial genus Lactobacillus, but lower levels of SCFAs and SCFA-producing bacteria including Fusobacterium, Bacteroides and Prevotella, compared with the soy protein-fed group. Further work is needed on the regulatory pathways linking dietary protein intake to gut microbiota.

  18. Anaerobic bacteria grow within Candida albicans biofilms and induce biofilm formation in suspension cultures.

    Science.gov (United States)

    Fox, Emily P; Cowley, Elise S; Nobile, Clarissa J; Hartooni, Nairi; Newman, Dianne K; Johnson, Alexander D

    2014-10-20

    The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival.

  19. A retrospective metagenomics approach to studying Blastocystis.

    Science.gov (United States)

    Andersen, Lee O'Brien; Bonde, Ida; Nielsen, Henrik Bjørn; Stensvold, Christen Rune

    2015-07-01

    Blastocystis is a common single-celled intestinal parasitic genus, comprising several subtypes. Here, we screened data obtained by metagenomic analysis of faecal DNA for Blastocystis by searching for subtype-specific genes in coabundance gene groups, which are groups of genes that covary across a selection of 316 human faecal samples, hence representing genes originating from a single subtype. The 316 faecal samples were from 236 healthy individuals, 13 patients with Crohn's disease (CD) and 67 patients with ulcerative colitis (UC). The prevalence of Blastocystis was 20.3% in the healthy individuals and 14.9% in patients with UC. Meanwhile, Blastocystis was absent in patients with CD. Individuals with intestinal microbiota dominated by Bacteroides were much less prone to having Blastocystis-positive stool (Matthew's correlation coefficient = -0.25, P metagenomics approach. The study serves as an example of how it is possible to retrospectively investigate microbial eukaryotic communities in the gut using metagenomic datasets targeting the bacterial component of the intestinal microbiome and the interplay between these microbial communities.

  20. Interspecific variations in the gastrointestinal microbiota in penguins

    Science.gov (United States)

    Dewar, Meagan L; Arnould, John P Y; Dann, Peter; Trathan, Phil; Groscolas, Rene; Smith, Stuart

    2013-01-01

    Despite the enormous amount of data available on the importance of the gastrointestinal (GI) microbiota in vertebrate (especially mammals), information on the GI microbiota of seabirds remains incomplete. As with many seabirds, penguins have a unique digestive physiology that enables them to store large reserves of adipose tissue, protein, and lipids. This study used quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA gene pyrosequencing to characterize the interspecific variations of the GI microbiota of four penguin species: the king, gentoo, macaroni, and little penguin. The qPCR results indicated that there were significant differences in the abundance of the major phyla Firmicutes, Bacteroides, Actinobacteria, and Proteobacteria. A total of 132,340, 18,336, 6324, and 4826 near full-length 16S rRNA gene sequences were amplified from fecal samples collected from king, gentoo, macaroni, and little penguins, respectively. A total of 13 phyla were identified with Firmicutes, Bacteroidetes, Proteobacteria, and Fusobacteria dominating the composition; however, there were major differences in the relative abundance of the phyla. In addition, this study documented the presence of known human pathogens, such as Campylobacter, Helicobacter, Prevotella, Veillonella, Erysipelotrichaceae, Neisseria, and Mycoplasma. However, their role in disease in penguins remains unknown. To our knowledge, this is the first study to provide an in-depth investigation of the GI microbiota of penguins. PMID:23349094