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1.
Ueli von Ah Valeria Mozzetti Christophe Lacroix Ehab E Kheadr Ismaïl Fliss Leo Meile 《BMC microbiology》2007,7(1):79
Background
Bifidobacteria are found at varying prevalence in human microbiota and seem to play an important role in the human gastrointestinal tract (GIT). Bifidobacteria are highly adapted to the human GIT which is reflected in the genome sequence of a Bifidobacterim longum isolate. The competitiveness against other bacteria is not fully understood yet but may be related to the production of antimicrobial compounds such as bacteriocins. In a previous study, 34 Bifidobacterium isolates have been isolated from baby faeces among which six showed proteinaceous antilisterial activity against Listeria monocytogenes. In this study, one of these isolates, RBL67, was further identified and characterized. 相似文献2.
Guglielmetti S Karp M Mora D Tamagnini I Parini C 《Applied microbiology and biotechnology》2007,74(5):1053-1061
In this study, we performed molecular characterization and sequence analysis of three plasmids from the human intestinal isolate
Bifidobacterium longum biovar longum NAL8 and developed a novel vector screening system. Plasmids pNAL8H (10 kb) and pNAL8M (4.9 kb) show close sequence similarity
to and the same gene organization as the already characterized B. longum plasmids. The B. longum plasmid pNAC1 was identified as being most closely related to pNAL8L (3.5 kb). However, DNA sequence analysis suggested that
direct repeat-rich sites could have promoted several recombination events to diversify the two plasmid molecules. We verified
the likely rolling circle replication of plasmid pNAL8L and studied the phylogenetic relationship in all the Bifidobacterium plasmids fully sequenced to date based on in silico comparative sequence analysis of their replication proteins and iteron regions. Our transformation experiments confirmed
that the ColE1 replication origin from high-copy-number pUC vectors could interfere with the replication apparatus of Bifidobacterium plasmids and give rise to false positive clones. As a result, we developed a system suitable for avoiding possible interference
by other functional replication modules on the vector and for screening functional replicons from wild-type plasmids.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users only. 相似文献
3.
Sophie Mathys Ueli von Ah Christophe Lacroix Ernö Staub Raffaella Mini Tania Cereghetti Leo Meile 《BMC biotechnology》2007,7(1):55
Background
Bacteriocin-producing lactic acid bacteria are commonly used as natural protective cultures. Among them, strains of the genus Pediococcus are particularly interesting for their ability to produce pediocin, a broad spectrum antimicrobial peptide with a strong antagonistic activity against the food-borne pathogen Listeria monocytogenes. Furthermore, there is increasing interest in isolating new bacteriocin-producing strains of human intestinal origin that could be developed for probiotic effects and inhibition of pathogenic bacteria in the gut. In this work, we typed a new strain, co-isolated from baby faeces together with a Bifidobacterium thermophilum strain, and characterized its proteinaceous compound with strong antilisterial activity. 相似文献4.
Previous reports have shown that Escherichia coli O157:H7 infection is strongly modified by intestinal microbes. In this paper, we examined whether bifidobacteria protect
against E. coli O157:H7 infections using gnotobiotic mice di-associated with Bifidobacterium strains (6 species, 9 strains) and E. coli O157:H7. Seven days after oral administration of each Bifidobacterium strain, the mice were orally infected with E. coli O157:H7 and their mortality was examined. Bifidobacterium longum subsp. infantis 157F-4-1 (B. infantis 157F) and B. longum subsp. longum NCC2705 (B. longum NS) protected against the lethal infection, while mice associated with all other Bifidobacterium strains, including type strains of B. longum subsp. infantis and B. longum subsp. longum, died. There were no significant differences in the numbers of E. coli O157:H7 in the faeces among the Bifidobacterium-associated mouse groups. However, the Shiga toxin concentrations in the cecal contents and sera of the GB mice associated
with B. infantis 157F and B. longum NS were significantly lower than those of the other groups. However, there were no significant differences in the volatile
fatty acid concentrations and histopathological lesions between these two groups. These data suggest that some strains of
B. longum subsp. longum/infantis can protect against the lethal infections of E. coli O157:H7 by preventing Shiga toxin production in the cecum and/or Shiga toxin transfer from the intestinal lumen to the bloodstream. 相似文献
5.
The health beneficial attributes of bifidobacteria and its safe association with the host gut has increased its significance as a probiotic. However delivering probiotic bifidobacteria with Minimum Biological Value (MBV) through product has always been a challenge. In the present study, an attempt was made to maintain the viability of native isolate of Bifidobacterium longum CFR 815j and deliver through ice-cream. B. longum CFR815j was microencapsulated in alginate starch capsules by emulsification followed by evaluation of bead stability in simulated gastrointestinal conditions. After incorporation in ice-cream, the effect on chemical properties, sensory parameters and meltdown characteristics of the product were also evaluated. Survival studies of B. longum revealed higher counts than 107 in the product which is essential for probiotic bacteria to exhibit beneficial effect. Further, all the properties of this ice-cream were comparable to the regular ice-cream. Our studies conclude that encapsulation was able to maintain the requisite MBV of bifidobacteria in ice-cream without affecting the sensory characteristics. 相似文献
6.
Background
Culture-independent methods based on the 16S ribosomal RNA molecule are nowadays widely used for assessment of the composition of the intestinal microbiota, in relation to host health or probiotic efficacy. Because Bifidobacterium thermophilum was only recently isolated from human faeces until now, no specific real-time PCR (qPCR) assay has been developed for detection of this species as component of the bifidobacterial community of the human intestinal flora. 相似文献7.
Background
The Brucella genome contains an insertion sequence (IS) element called IS711 or IS6501, which is specific to the genus. The copy number of IS711 varies in the genome of the different Brucella species, ranging from 7 in B. abortus, B. melitensis and B. suis to more than 30 in B. ovis and in Brucella strains isolated from marine mammals. At present, there is no experimental evidence of transposition of IS711, but the occurrence of this element with a high copy number in some species, and the isolation of Brucella strains with "ectopic" copies of IS711 suggested that this IS could still transpose. 相似文献8.
Rachel Balder Serena Lipski John J Lazarus William Grose Ronald M Wooten Robert J Hogan Donald E Woods Eric R Lafontaine 《BMC microbiology》2010,10(1):250
Background
Burkholderia pseudomallei and Burkholderia mallei cause the diseases melioidosis and glanders, respectively. A well-studied aspect of pathogenesis by these closely-related bacteria is their ability to invade and multiply within eukaryotic cells. In contrast, the means by which B. pseudomallei and B. mallei adhere to cells are poorly defined. The purpose of this study was to identify adherence factors expressed by these organisms. 相似文献9.
Ying Huang Xin Wang Zhigang Cui Yuhuan Yang Yuchun Xiao Liuying Tang Biao Kan Jianguo Xu Huaiqi Jing 《BMC microbiology》2010,10(1):211
Background
Yersinia enterocolitica is an enteric pathogen that invades the intestinal mucosa and proliferates within the lymphoid follicles (Peyer's patches). The attachment invasion locus (ail) mediates invasion by Y. enterocolitica and confers an invasive phenotype upon non-invasive E. coli; ail is the primary virulence factor of Y. enterocolitica. The ferrioxamine receptor (foxA) located on the Y. enterocolitica chromosome, together with its transport protein, transports a siderophore specific for ferric ion. Currently, ail is the primary target gene for nucleic acid detection of pathogenic Y. enterocolitica. 相似文献10.
Background
The induction of metalloprotease encoded by empA in Vibrio anguillarum occurs at high cell density in salmon intestinal mucus. Previously we have shown that there are significant differences in empA expression in two strains of V. anguillarum, M93Sm and NB10. It is hypothesized that differences in empA regulation are due to differences in binding of regulatory elements. 相似文献11.
Background
Shigella is the etiological agent of shigellosis, a disease responsible for more than 500,000 deaths of children per year, in developing countries. These pathogens colonize the intestinal colon, invade, spreading to the other enterocytes. Breastfeeding plays a very important role in protecting infants from intestinal infections. Amongst milk compounds, glycosylated proteins prevent the adhesion of many enteropathogens in vitro. The aim of this work was to determine the effect of human milk proteins on the colonization potential of Shigella dysenteriae, S. flexneri and S. sonnei. To fulfill this purpose, pooled milk samples from five donors, were fractionated by gel filtration and affinity chromatography. Using tissue culture, the milk fractions obtained were tested in Shigella adhesion and invasion assays. 相似文献12.
Background
Anopheles gambiae females are the world's most successful vectors of human malaria. However, a fraction of these mosquitoes is refractory to Plasmodium development. L3-5, a laboratory selected refractory strain, encapsulates transforming ookinetes/early oocysts of a wide variety of Plasmodium species. Previous studies on these mosquitoes showed that one major (Pen1) and two minor (Pen2, Pen3) autosomal dominant quantitative trait loci (QTLs) control the melanotic encapsulation response against P. cynomolgi B, a simian malaria originating in Malaysia. 相似文献13.
Valentine Cleusix Christophe Lacroix Sabine Vollenweider Marc Duboux Gwenaelle Le Blay 《BMC microbiology》2007,7(1):101
Background
Reuterin produced from glycerol by Lactobacillus reuteri, a normal inhabitant of the human intestine, is a broad-spectrum antimicrobial agent. It has been postulated that reuterin could play a role in the probiotic effects of Lb. reuteri. Reuterin is active toward enteropathogens, yeasts, fungi, protozoa and viruses, but its effect on commensal intestinal bacteria is unknown. Moreover reuterin's mode of action has not yet been elucidated. Glutathione, a powerful antioxidant, which also plays a key role in detoxifying reactive aldehydes, protects certain bacteria from oxidative stress, and could also be implicated in resistance to reuterin. 相似文献14.
Background
Campylobacter jejuni has been divided into two subspecies: C. jejuni subsp. jejuni (Cjj) and C. jejuni subsp. doylei (Cjd). Nearly all of the C. jejuni strains isolated are Cjj; nevertheless, although Cjd strains are isolated infrequently, they differ from Cjj in two key aspects: they are obtained primarily from human clinical samples and are associated often with bacteremia, in addition to gastroenteritis. In this study, we utilized multilocus sequence typing (MLST) and a DNA microarray-based comparative genomic indexing (CGI) approach to examine the genomic diversity and gene content of Cjd strains. 相似文献15.
Kenneth M Noll Pascal Lapierre J Peter Gogarten Dhaval M Nanavati 《BMC evolutionary biology》2008,8(1):7
Background
The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. 相似文献16.
Inés Ponce de León Juan Pablo Oliver Alexandra Castro Carina Gaggero Marcel Bentancor Sabina Vidal 《BMC plant biology》2007,7(1):52
Background
Vascular plants respond to pathogens by activating a diverse array of defense mechanisms. Studies with these plants have provided a wealth of information on pathogen recognition, signal transduction and the activation of defense responses. However, very little is known about the infection and defense responses of the bryophyte, Physcomitrella patens, to well-studied phytopathogens. The purpose of this study was to determine: i) whether two representative broad host range pathogens, Erwinia carotovora ssp. carotovora (E.c. carotovora) and Botrytis cinerea (B. cinerea), could infect Physcomitrella, and ii) whether B. cinerea, elicitors of a harpin (HrpN) producing E.c. carotovora strain (SCC1) or a HrpN-negative strain (SCC3193), could cause disease symptoms and induce defense responses in Physcomitrella. 相似文献17.
Jiu-Cun Wang Syeling Lai Xinjian Guo Xuefeng Zhang Benoit de Crombrugghe Sonali Sonnylal Frank C Arnett Xiaodong Zhou 《Arthritis research & therapy》2010,12(2):R60
Introduction
SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs. 相似文献18.
Chun-Li Wang Yang-Bin Fan Hsiao-Hwa Lu Tung-Hu Tsai Ming-Cheng Tsai Hui-Po Wang 《Journal of biomedical science》2010,17(1):71
Background
l-Dopa has been used for Parkinson's disease management for a long time. However, its wide variety in the rate and the extent of absorption remained challenge in designing suitable therapeutic regime. We report here a design of using d-phenylglycine to guard l-dopa for better absorption in the intestine via intestinal peptide transporter I (PepT1). 相似文献19.