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41.
The carcass rinse procedure is a method commonly used for the detection of Campylobacter spp. on processed poultry products. Alternatively, carcass exudate (weep or drip), a viscous fluid comprised of blood and water that leaks into packaging, can also be sampled. It is unknown however if direct carcass rinse or exudate/weep can be utilized to preferentially recover different Campylobacter spp. subtypes. If there is a difference in subtypes recovered, the Campylobacter spp. subtypes from carcass rinse analysis may not be indicative of consumer exposure, as the exudate is the fluid to which consumers are potentially exposed to due to kitchen cross-contamination. Experiments were conducted to determine if there are differences in recovery of Campylobacter spp. subtypes between the two methodologies. The experiment was performed in triplicate using three flocks located on different farms. For each flock, 50 fecal samples were obtained on the farm, 25 carcass rinses during pre-chill processing, 25 carcass rinses during post-chill processing, and 50 samples from exudate from carcasses stored at 4 degrees C (25 after 2-day storage and 25 after 6-day storage). Each sample type was cultured for Campylobacter spp. Isolates recovered from positive samples were subtyped using flaA SVR (flagellin A-short variable region) DNA sequence typing and compared for relatedness. The data demonstrated that multiple subtypes of Campylobacter jejuni were present in a flock, and that subtypes present in a flock during production were also present on the final processed product. Subtypes recovered by the two recovery methodologies were similar based on flaA SVR classification. Combining the totals from all 3 flocks a total of 10 flaA SVR subtypes were recovered from post-chill carcass rinses and 9 subtypes recovered from 6-day exudate samples. 相似文献
42.
Objectives: The aim of this study was to assess persistence and tissue invasion of Candida albicans strains isolated from a 65 year‐old patient with chronic hyperplastic candidosis (CHC), that subsequently developed into squamous cell carcinoma (SCC). Materials and Methods: C. albicans (n=7) were recovered from the oral cavity of the patient over seven years. Confirmation of CHC and SCC in this patient was achieved by histopathological examination of incisional biopsy tissue. DNA fingerprinting was performed on the seven isolates from the CHC patient together with a further eight isolates from patients with normal oral mucosa (n=2), chronic atrophic candidosis (n=1), SCC (n=1) and CHC (n=4). Genotyping involved the use of inter‐repeat PCR using the eukaryotic repeat primer 1251. Characterisation of the tissue invasive abilities of the isolates was achieved by infecting a commercially available reconstituted human oral epithelium (RHE; SkinEthic, Nice, France). After 24 h. C. albicans tissue invasion was assessed by histopathological examination. Results: DNA fingerprinting demonstrated strain persistence of C. albicans in the CHC patient over a seven year period despite provision of systemic antifungal therapy. The strain of C. albicans isolated from this patient was categorised as a high invader within the RHE compared to other isolates. Conclusions: Candidal strain persistence was evident in a patient with CHC over seven years. This persistence may be due to incomplete eradication from the oral cavity following antifungal therapy or subsequent recolonisation from other body sites or separate exogenous sources. The demonstration of enhanced in vitro tissue invasion by this particular strain may, in part, explain the progression to carcinoma. 相似文献
43.
Smirnova I Poltorak A Chan EK McBride C Beutler B 《Genome biology》2000,1(1):research002.1-research00210
Background
Differences in responses to bacterial surface lipopolysaccharides (LPSs) are apparent between and within mammalian species. It has been shown in mice that resistance to LPS is caused by defects in the Toll-like receptor 4 gene (Tlr4), the product of which is thought to bind LPS and mediate LPS signal transduction in immune system cells. 相似文献44.
Lukas Rüber Maurice Kottelat Heok Hui Tan Peter KL Ng Ralf Britz 《BMC evolutionary biology》2007,7(1):38
Background
Paedocypris, a highly developmentally truncated fish from peat swamp forests in Southeast Asia, comprises the world's smallest vertebrate. Although clearly a cyprinid fish, a hypothesis about its phylogenetic position among the subfamilies of this largest teleost family, with over 2400 species, does not exist. Here we present a phylogenetic analyses of 227 cypriniform taxa, including 213 cyprinids, based upon complete mitochondrial DNA cytochrome b nucleotide sequences in order to determine the phylogenetic position of Paedocypris and to study the evolution of miniaturization among cyprinids. 相似文献45.
Meinersmann RJ Phillips RW Hiett KL Fedorka-Cray P 《Applied and environmental microbiology》2005,71(10):6368-6374
The DNA sequence of the flaA short variable region (SVR) was used to analyze a random population of Campylobacter isolates to investigate the weakly clonal population structure of members of the genus. The SVR sequence from 197 strains of C. jejuni and C. coli isolated from humans, bovine, swine, and chickens identified a group of 43 strains containing disparate short variable region sequences compared to the rest of the population. This group contains both C. jejuni and C. coli strains but disproportionately consisted of bovine isolates. Relative synonymous codon usage analysis of the sequences identified two groups: one group typified C. jejuni, and the second group was characteristic for C. coli and the disparate alleles were not clustered. The data show that there is significant differentiation of Campylobacter populations according to the source of the isolate even without considering the disparate isolates. Even though there is significant differentiation of chicken and bovine isolates, the bovine isolates did not show any difference in ability to colonize chickens. It is possible that disparate sequences were obtained through the lateral transfer of DNA from Campylobacter species other than C. jejuni and C. coli. It is evident that recombination within the flaA SVR occurs rapidly. However, the rate of migration between populations appears to limit the distribution of sequences and results in a weakly clonal population structure. 相似文献
46.
An antigen in the outer membrane protein (OMP) fraction of
Campylobacter jejuni was identified and characterized. Western blot
analysis demonstrated antigenic differences in this protein between two
congenic C. jejuni strains. Strain A74/C, which colonizes chickens,
expressed the antigen at 34 kDa, while strain A74/O, which poorly colonizes
chickens, expressed the antigen at 32 and 34 kDa. A genomic library was
constructed in λgt11 with DNA from A74/O and screened with antibody raised
against C. jejuni OMPs. A clone that possessed a 1.3-kb insert and
expressed an immunoreactive protein fused to β-galactosidase was isolated
and purified. DNA sequence analysis revealed the insert contained one open
reading frame 864 bases long. The deduced amino acid sequence demonstrated
56.3% similarity with Bacillus steorothermophilus glnH, a
glutamine-binding protein, and 54.0% similarity with C. jejuni
PEB1, a putative colonization adhesin. Southern hybridization, Northern
hybridization, and DNA sequence analyses of the congenic colonizing and
noncolonizing strains of C. jejuni failed to distinguish the two
strains and revealed only one copy of the gene. Post-translational
modification may be an alternate explanation for the antigenic differences
seen between the two strains.
Received: 15 October 1996 / Accepted: 3 December 1996 相似文献
47.
Volozhantsev NV Oakley BB Morales CA Verevkin VV Bannov VA Krasilnikova VM Popova AV Zhilenkov EL Garrish JK Schegg KM Woolsey R Quilici DR Line JE Hiett KL Siragusa GR Svetoch EA Seal BS 《PloS one》2012,7(5):e38283
Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium responsible for human food-borne disease as well as non-food-borne human, animal and poultry diseases. Because bacteriophages or their gene products could be applied to control bacterial diseases in a species-specific manner, they are potential important alternatives to antibiotics. Consequently, poultry intestinal material, soil, sewage and poultry processing drainage water were screened for virulent bacteriophages that lysed C. perfringens. Two bacteriophages, designated ΦCPV4 and ΦZP2, were isolated in the Moscow Region of the Russian Federation while another closely related virus, named ΦCP7R, was isolated in the southeastern USA. The viruses were identified as members of the order Caudovirales in the family Podoviridae with short, non-contractile tails of the C1 morphotype. The genomes of the three bacteriophages were 17.972, 18.078 and 18.397 kbp respectively; encoding twenty-six to twenty-eight ORF's with inverted terminal repeats and an average GC content of 34.6%. Structural proteins identified by mass spectrometry in the purified ΦCP7R virion included a pre-neck/appendage with putative lyase activity, major head, tail, connector/upper collar, lower collar and a structural protein with putative lysozyme-peptidase activity. All three podoviral bacteriophage genomes encoded a predicted N-acetylmuramoyl-L-alanine amidase and a putative stage V sporulation protein. Each putative amidase contained a predicted bacterial SH3 domain at the C-terminal end of the protein, presumably involved with binding the C. perfringens cell wall. The predicted DNA polymerase type B protein sequences were closely related to other members of the Podoviridae including Bacillus phage Φ29. Whole-genome comparisons supported this relationship, but also indicated that the Russian and USA viruses may be unique members of the sub-family Picovirinae. 相似文献
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Ceribelli A Krzyszczak ME Li Y Ross SJ Chan JY Chan EK Burlingame RW Webb TT Bubb MR Sobel ES Reeves WH Satoh M 《Arthritis research & therapy》2011,13(4):R119-7