Die klassische Identifizierung von obligat anaeroben Bakterien ist mit einem hohen Labor- und Zeitaufwand verbunden. Um festzustellen, ob die Identifizierung mittels Matrix-unterstützter Laser-Desorption/Ionisation und Massenspektrometrie mit Flugzeitanalysator (Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; MALDI-TOF MS) ein Verfahren ist, um obligate Anaerobier eindeutig zu identifizieren, wurde mit der vorliegenden Arbeit die Identifizierung von unterschiedlichen Spezies der B. fragilis Gruppe mittels MALDI-TOF MS untersucht. Hierfür wurden 105 obligate Anaerobier der B. fragilis Gruppe aus der Stammsammlung des Institutes für Medizinische Mikrobiologie und Infektionsepidemiologie der Universität Leipzig untersucht. Es fanden sich für die untersuchten Erreger Spektren mit sehr guter Auflösung. Eine Identifizierung und Differenzierung war eindeutig möglich. Unter Verwendung dieser Daten wurde eine Referenzdatenbank erstellt. Die erhaltenen Ergebnisse wurden mittels einer verblindeten Studie überprüft, wobei 52 von 53 (98,1%) der untersuchten Stämme eindeutig identifiziert werden konnten. Dies schließt ebenfalls die Identifizierung und Differenzierung von 15 Metronidazol-sensiblen/ Enterotoxin-negativen, 8 Metronidazol-resistenten/ Enterotoxin-negativen und 8 Metronidazol-sensiblen/ Enterotoxin-positiven B. fragilis Stämmen ein. Die Identifizierung mittels MALDI-TOF MS ist somit eine zuverlässige Methode zur Identifizierung von obligaten Anaerobiern der B. fragilis Gruppe. Weiterhin finden sich Hinweise, dass ein Nachweis von Resistenz-, Virulenz- und Pathogenitätsfaktoren mittels MALDI-TOF MS bei diesen Erregern möglich ist.

Thesis (doctoral)--Vrije Universiteit te Amsterdam, 1981. / Summary in Dutch. Includes bibliographical references (p. 115-123).

Thesis (doctoral)--Vrije Universiteit te Amsterdam, 1981. / Summary in Dutch. Includes bibliographical references (p. 115-123).

No description available.

The human gut is home to a significant number of microorganisms including the dominant symbiont Bacteroides thetaiotaomicron. This microbe is predicted to possess an array of glycoside hydrolases, majority of which are involved in starch utilization. Presented here is a comparative functional analysis of two alpha-glucosidases, Family 31 Glycoside Hydrolases from Bacteroides thetaiotaomicron. Enzymatic kinetics revealed these enzymes both preferentially cleave alpha-(1,6) linkage in comparison to the predicted alpha-(1,4) and favour maltose derived substrates of longer length.

The human gut is home to a significant number of microorganisms including the dominant symbiont Bacteroides thetaiotaomicron. This microbe is predicted to possess an array of glycoside hydrolases, majority of which are involved in starch utilization. Presented here is a comparative functional analysis of two alpha-glucosidases, Family 31 Glycoside Hydrolases from Bacteroides thetaiotaomicron. Enzymatic kinetics revealed these enzymes both preferentially cleave alpha-(1,6) linkage in comparison to the predicted alpha-(1,4) and favour maltose derived substrates of longer length.

SILVA, Janice Oliveira. Sensibilidade a antimicribianos de bacteroidales de microbiota intestinal de cães e o efeito de concentracöes subinibitórias de antimicrobianos na formação de biofilme in vitro. 2015. 71 f. Dissertação (Mestrado em Microbiologia Médica) – Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by denise santos (denise.santos@ufc.br) on 2015-12-21T14:02:09Z No. of bitstreams: 1 2012_dis_josilva.pdf: 3676948 bytes, checksum: 203813cb8b6b1cfde06f219baa3a05cb (MD5) / Approved for entry into archive by denise santos(denise.santos@ufc.br) on 2015-12-21T14:03:06Z (GMT) No. of bitstreams: 1 2012_dis_josilva.pdf: 3676948 bytes, checksum: 203813cb8b6b1cfde06f219baa3a05cb (MD5) / Made available in DSpace on 2015-12-21T14:03:06Z (GMT). No. of bitstreams: 1 2012_dis_josilva.pdf: 3676948 bytes, checksum: 203813cb8b6b1cfde06f219baa3a05cb (MD5) Previous issue date: 2015 / The Bacteroides and Parabacteroides spp are involved in serious diseases like abscesses and bacteremia in humans and animals. These bacteria are characterized by antimicrobial resistance and B. fragilis is the main anaerobic bacteria isolated from the intestine which can form biofilm. The aim of this study was to isolate Bacteroides and Parabacteroides strains from dogs intestinal tract, to investigate the antimicrobial susceptibility and to evaluate the action of antimicrobials subinhibitory concentrations on biofilm formation. A total of 30 strains were evaluated in this study. The assays were performed in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines and other established methods. Antimicrobial susceptibility was observed against penicillin, amoxicillin-clavulanic acid, cefoxitin, imipenem, clindamycin, ciprofloxacin, enrofloxacin, tetracycline, chloramphenicol and metronidazole. Fifteen B. fragilis strains were tested for biofilm formation and the stronger four biofilm producer strains were chosen to evaluate the effect of subinhibitory concentrations (1/2 and 1/4MIC) of six antimicrobials on biofilm formation. B. fragilis was the most frequently isolated anaerobic bacteria followed by P. distasonis and B. vulgatus. The isolates were uniformly susceptible to metronidazole, imipenem and chloramphenicol and were penicillin resistant. Tetracycline and clindamycin were active against 50% and 33% of the strains respectively. The biofilm production of all four strains was uniformly and significantly lower (P<0.05) after growth with ½ MIC and ¼ MIC of imipenem and metronidazole. The induction of biofilm formation was observed in two isolates at ½ MIC and ¼ MIC of enrofloxacin. / Os gêneros Bacteroides e Parabacteroides estão envolvidos em doenças graves como abscessos e bacteremia em humanos e animais. Estas bactérias são caracterizadas pela resistência antimicrobiana e B. fragilis é a principal bactéria anaeróbica isolada do intestino que pode formar biofilme. O objetivo deste trabalho foi isolar Bacteroides e Parabacteroides do trato intestinal de cães, para avaliar a sensibilidade antimicrobiana e a ação de concentrações subinibitórias de antimicrobianos sobre a formação de biofilme. Um total de 30 amostras foram avaliadas neste estudo. Os ensaios foram realizados de acordo com os métodos e as diretrizes de Clínicals Laboratory Standards Institute (CLSI) e outras metodologias estabelecidas. Os antimicrobianos testados contra Bacteroides e Parabacteroides foram: penicilina, amoxicilina-ácido clavulânico, cefoxitina, imipenem, clindamicina, ciprofloxacina, enrofloxacina, tetraciclina, cloranfenicol e metronidazol. Quinze cepas de B. fragilis foram testadas para a formação de biofilme e as quatro cepas mais produtoras de biofilmes foram escolhidas para avaliar o efeito de concentrações subinibitórias (1/2 e 1/4CIM) de seis antimicrobianos sobre a formação de biofilme. B. fragilis foi a bactéria mais frequentemente isolada seguida por P. distasonis e B. vulgatus. Os isolados foram uniformemente sensíveis ao metronidazol, imipenem e cloranfenicol e foram resistentes à penicilina. Tetraciclina e clindamicina foram ativas contra 50% e 33% das cepas, respectivamente. A produção de biofilme de todas as quatro cepas foi uniforme e significativamente menor (P <0,05) após crescimento com ½ e ¼CIM de imipenem e metronidazol. A indução da formação de biofilme foi observada em duas cepas com ½ e ¼ CIM de enrofloxacina.

Thirty-one strains from the genus Bacteriods (12 species and subspecies) were tentatively identified using cellular fatty acid analysis. The procedures were slightly modified to permit use of packed-column, thermal conductivity instruments, such as would be found in clinical laboratories currently using analysis of volatile/non volatile fatty acids as part of a scheme for the identification of anaerobes. Different types of rapid extraction and commonly used meida . Teh overall rate of correct identification for the black-pigmented and related species of Bacteriodes was 67%. The considerable savings of time in obtaining presumed identification using inexpensive material may be of interest for the routine clinical microbiology laboratory.

In the course of studies on degradation of dietary fiber by the human colon bacteria, a number of Bacteroides strains from the human colon have been found to degrade polygalacturonic acid and/or pectin. Four of these strains were examined for presence of polygalacturonate lyase (PGAL). The Bacteroides strains studied synthesized inducible, cell-associated PGALs when the bacteria were grown on media containing polygalacturonic acid or on peanut cell wall (a prototype dietary fiber with a uronide content of 14.0%) as the sole carbon source. No PGAL activity could be detected in cultures grown on media containing glucose or D-galacturonate. The PGALs produced by the four Bacteroides strains had properties similar to other bacterial PGALs: An alkaline pH optima (8.5), stimulation of activity by calcium ions. complete inhibition by ethylenediaminetetraacetic acid (EDTA), preference for polygalacturonic acid as a substrate over pectin, and accumulation of unsaturated products which absorb at 235 nm. The Bacteroides PGALs catalyzed partial degradation of the uronides of peanut cell wall substrate, but at a slower rate compared to their action on polygalacturonic acid substrate. / M.S.

Family 6 Glycosyltransferases (GT6s) are involved in the biosynthesis of complex glycans and can be found in all vertebrates, cyanophages, and some bacteria and unicellular eukaryotes. Understanding variations within family 6 GTs is important because of the roles of their products in cellular recognition, intercellular interactions, pathogenicity, and immunity and is likewise important for understanding the evolution of GTs. PaGT6 (from Parchlamydia acanthamoebae) and α3GT (from Bos taurus) both require a divalent metal ion for catalysis which binds to a DXD motif. In BoGT6a from Bacteroides ovatus a NXN motif replaces DXD, and activity is metal-independent. However, mutating the NXN motif in BoGT6a to DXD did not introduce metal-dependency, indicating that metal-dependency is linked to additional differences. Calorimetric studies have shown that the presence of a divalent metal ion enhances UDP and donor substrate binding to PaGT6 and causes an increase in the entropy of the interaction. Protein modelling of PaGT6 has revealed that the presence of Mn2+ allows a hydrogen bond to form between Asp 97 and UDP-GalNAc, causing the donor substrate to bend and form hydrogen bonds with His 119, Asn 229, Lys 228, and Arg 234. These interactions do not occur in the absence of Mn2+. Investigation of acceptor substrate binding revealed that the presence of UDP enhances acceptor substrate binding to BoGT6a and PaGT6. Calorimetric titrations of BoGT6a with 2-fucosyllactose in the absence and presence of UDP showed that UDP increases the affinity of 2-fucosyllactose 16-fold with little effect on ΔH. Measurements of ΔCp for 2-fucosyllactose binding indicate that there is not a hydrophobic effect for the binding of 2-fucosyllactose. The preferred acceptor substrate for the bovine and Bacteroides GT6 has a β-1,4 linked galactose, but P. acanthamoebae GT6 prefers an acceptor substrate with a β-1,3 linked galactose. The N-terminus of the catalytic domain of bacterial GT6s is truncated by 47 residues relative to the catalytic domain of bovine α3GT. Removal of this region from α3GT results in an unfolded protein, indicating that although this region is not directly involved in substrate binding, it forms interactions necessary for the stability of the catalytic domain. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection