There is little known about the sequences that mediate initiation of transcription in Bacteroides fragilis, thus transcriptional start sites for 13 new genes were determined and a total 23 promoter regions upstream aligned similarities noted. A region at −7 contained consensus sequence TAnnTTTG centered −33, another TTTG motif was found majority promoters examined. Canonical, Escherichia coli, −10 −35 not readily apparent. Mutations within indicated residues essential since changes this...

A clinical isolate of Bacteroides vulgatus was resistant to tetracycline, clindamycin, ampicillin, cephaloridine, cefoxitin, and other beta-lactam antibiotics except imipenem. beta-Lactam resistance mediated by a membrane-associated, clavulanate-sensitive cephalosporinase capable degrading cephalosporins penicillins. Cefoxitin also degraded but at slow rate. The cefoxitin (Fxr) determinant cloned from B. genomic libraries that were prepared in Escherichia coli then mated with fragilis for...

The transfer of tetracycline resistance among strains Clostridium difficile is described. Transfer occurred by a conjugation-like event that was insensitive to deoxyribonuclease, could not be mediated donor culture filtrates or chloroform-treated cultures, and required cell-to-cell contact. Tetracycline-resistant progeny recovered from matings displayed phenotype identical the in level resistance, constitutive expression, transmissibility. Although original tetracycline-resistant contained 5...

Survival of Bacteroides fragilis in the presence oxygen was dependent on ability bacteria to synthesize new proteins, as determined by inhibition protein synthesis after exposure. The B. profile significantly altered either a shift from anaerobic aerobic conditions with or without paraquat addition exogenous hydrogen peroxide. As autoradiography two-dimensional gel electrophoresis, approximately 28 newly synthesized proteins were detected response oxidative conditions. These found have broad...

ABSTRACT The opportunistic pathogen Bacteroides fragilis is a commensal organism in the large intestine, where it utilizes both dietary and host-derived polysaccharides as source of carbon energy. In this study, four-gene operon required for starch utilization was identified. also found to be oxygen responsive thus designated osu o xygen-induced s tarch u tilization. first three genes were predicted encode outer membrane proteins involved binding, fourth gene, osuD , encoded an amylase...

Summary The intestinal anaerobic symbiont, Bacteroides fragilis , is highly aerotolerant and resistant to H 2 O . Analysis of the transcriptome showed that expression 45% genome was significantly affected by oxidative stress. gene patterns suggested exposure stress induced an acute response rapidly minimize immediate effects reactive oxygen species, then upon extended a broad metabolic induced. This genes encoding enzymes can supply reducing power for detoxification restore energy‐generating...

Abstract Bacteroides species are Gram‐negative, obligate anaerobic bacteria. They the predominant indigenous bacterial in human intestinal tract, where they play an important role normal physiology of host, but can also be significant opportunistic pathogens. The fact that these anaerobes is prevailing feature affects methodology used for their cultivation. Several techniques described culturing; glove box and jars two most adaptable to a range research needs. Straightforward methods...

In this study we report the identification and role of alkyl hydroperoxide reductase (ahp) gene in Bacteroides fragilis. The two components ahp, ahpC, ahpF, are organized an operon, deduced amino acid sequences revealed that B. fragilis AhpCF shares approximately 60% identity to orthologues other gram-positive gram-negative bacteria. Northern blot hybridization analysis total RNA showed ahpCF genes were transcribed as a polycistronic 2.4-kb mRNA ahpC also was present 0.6-kb monocistronic...

gamma-Glutamyl kinase, the first enzyme of proline biosynthetic pathway, was purified to homogeneity from an Escherichia coli strain resistant analog 3,4-dehydroproline. The had a native molecular weight 236,000 and apparently comprised six identical 40,000-dalton subunits. Enzymatic activity protein detectable only in assays containing highly gamma-glutamyl phosphate reductase, second pathway. Plots kinase as function glutamate concentration were sigmoidal, with half-saturation value for 33...

Bacteroides fragilis CS30 is a clinical isolate resistant to high concentrations of benzylpenicillin and cephaloridine but not cephamycin or penem antibiotics. beta-Lactam resistance mediated by chromosomally encoded cephalosporinase produced at level. The gene encoding this beta-lactamase was cloned from genomic libraries constructed in Escherichia coli then mated with B. 638 for identification ampicillin-resistant (Apr) strains. Apr transconjugants contained nitrocefin-reactive protein the...

Results of this study showed that the anaerobic, opportunistic pathogen Bacteroides fragilis lacks glutathione/glutaredoxin redox system and possesses an extensive number putative thioredoxin (Trx) orthologs. Analysis genome sequence revealed six Trx orthologs absence genes required for synthesis glutathione glutaredoxins. In addition, it was shown reductase (TrxB)/Trx is major or sole thiol/disulfide cellular homeostasis in anaerobic bacterium. Expression B. trxB gene induced following...

Studies of the microbiota dental plaque have been hampered by an inability to cultivate all or even a majority microorganisms present in this site. Failure recover could be attributed at least 3 types losses; inadequate dispersion, adhesion glassware used dilution and spreading, any single cultural environment resident microorganisms. Clumps more effectively dispersed sonic oscillation than tissue grinders. Anaerobic sonication proved significantly effective maintaining viability isolates...

Significance Human microbiota have a huge impact on health from proper development of the immune system to maintenance normal physiological processes. The largest concentration microbes is found in colon, which home hundreds bacterial species, most are obligate anaerobes. This population also poses significant threat opportunistic infection, and all species present, Bacteroides fragilis anaerobe frequently isolated extraintestinal infections intestinal origin. findings presented here...

ABSTRACT The peroxide response-inducible genes ahpCF , dps and katB in the obligate anaerobe Bacteroides fragilis are controlled by redox-sensitive transcriptional activator OxyR. This is first functional oxidative stress regulator identified characterized anaerobic bacteria. oxyR were found to be divergently transcribed, with an overlap their respective promoter regulatory regions. B. OxyR Dps proteins showed high identity homologues from a closely related anaerobe, Porphyromonas gingivalis...

Resistance to tetracycline and lincosamide antibiotics was transferred en bloc from a strain of Bacteroides fragilis (V503) plasmidless uniformis (V528) during in vitro filter matings. transfer detected at frequencies 10(-5) 10(-6) drug-resistant progeny per input donor cell dependent on cell-to-cell contact donors recipients. Transfer insensitive DNase not mediated by chloroform- or filter-sterilized broth cultures. A determinant for resistance cefoxitin V503 this system. contained 3.7 x...

The sequence of the EscherichiacoliproC gene which encodes for Δ 1 -pyrroline-5-carboxylate (PCA) reductase was determined. Overproduction proC product via an expression plasmid carrying bacteriophage λp L promoter allowed purification to homogeneity PCA by affinity adsorption chromatography. NH 2 and C00H-term1nal analysis amino add composition purified protein 1s consistent with reported. molecular weight monomer is 28,112.

A 2.9 kb DNA fragment carrying the Escherichia coli proBA region, which encodes first two enzymes of proline biosynthetic pathway, was subcloned onto an expression plasmid both bacteriophage lambda PL promoter (lambda PL) and gene encoding a thermolabile cI repressor protein (cI857). Derepression by thermal inactivation cI857 resulted in simultaneous overproduction proB (gamma-glutamyl kinase) proA phosphate reductase) products. Nucleotide sequence analysis locus allowed assignments...

Chimeric plasmids able to replicate in Bacteroides fragilis or B. and Escherichia coli were constructed used as molecular cloning vectors. The 2.7-kilobase pair (kb) cryptic plasmid pBI143 the E. vector pUC19 two replicons for these constructions. Selection of vectors was made possible by ligation a restriction fragment bearing clindamycin resistance (Ccr) determinant from R plasmid, pBF4;Ccr not expressed coli. chimeric ranged 5.3 7.3 kb size contained at least 10 unique enzyme recognition...