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61.
AIMS: The aim of this research was to compare excision sampling with polyurethane and cellulose acetate sponge swabbing for the recovery of total viable counts and Enterobacteriaceae on meat carcasses. METHODS AND RESULTS: Two sample types were used to compare the methods: (i) individual samples, taken from four sites on each carcass and (ii) composite samples, created by pooling the samples from four sites from an additional set of carcasses. When the polyurethane sponge and excision method were compared for individual sites, there were no significant differences in bacterial recovery on beef and pork carcasses and on two of four sites on lamb carcasses. However, when samples from each site were pooled, the excision method was more efficient than either swabbing method across the three animal species. CONCLUSIONS: Sampling using the polyurethane sponge represents an equivalent alternative method to excision for the bacteriological sampling of carcass surfaces which is nondestructive and less labour intensive. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides the scientific basis for using sponge swabbing instead of excision in compliance with 2001/471/EC. 相似文献
62.
Spatial epidemiology and natural population structure of Campylobacter jejuni colonizing a farmland ecosystem 总被引:3,自引:0,他引:3
French N Barrigas M Brown P Ribiero P Williams N Leatherbarrow H Birtles R Bolton E Fearnhead P Fox A 《Environmental microbiology》2005,7(8):1116-1126
Recent progress in determining the population structure of Campylobacter jejuni, and discerning associations between genotypes and specific niches, has emphasized the shortfall in our understanding of the ecology and epidemiology of this bacterium. We examined the natural structure of the C. jejuni community associated with cattle farmland in the UK by structured spatiotemporal sampling of habitats, including livestock and wild animal faeces, environmental water and soil, over a 10-week period within a 100 km2 area. A total of 172 isolates were characterized using multilocus sequence typing into 65 sequence types (STs). Isolates from cattle faeces were significantly over-represented in the ST-61 complex, whereas isolates from wildlife faeces and water were more likely to belong to the ST-45 complex and a number of unusual STs, many of which were first encountered during this study. Sampling within a narrow spatiotemporal window permitted the application of novel statistical methods exploring the relationship between the genetic relatedness and spatial separation of isolates. This approach showed that isolates from the same sampling squares and squares separated by <1.0 km were genetically more similar than isolates separated by greater distances. Our study demonstrates the potential of multilocus sequence typing combined with spatial modelling in exploring natural transmission pathways for C. jejuni. 相似文献
63.
64.
Role of interleukin-4 in regulation of age-related inflammatory changes in the hippocampus 总被引:7,自引:0,他引:7
Nolan Y Maher FO Martin DS Clarke RM Brady MT Bolton AE Mills KH Lynch MA 《The Journal of biological chemistry》2005,280(10):9354-9362
It is well documented that long term potentiation (LTP) is impaired in the hippocampus of the aged animal. Among the changes that contribute to this impairment is an increase in hippocampal concentration of the pro-inflammatory cytokine interleukin-1beta (IL-1beta), and increased IL-1beta-induced signaling. In this study we investigated the possibility that these changes were a consequence of decreased concentration of the anti-inflammatory cytokine, IL-4, and decreased IL-4-stimulated signaling. We report that functional IL-4 receptors are expressed on granule cells of the dentate gyrus and that receptor activation results in phosphorylation of JAK1 and STAT6. Hippocampal IL-4 concentration was decreased with age, and this was accompanied by a decrease in phosphorylation of JAK1 and STAT6. The evidence indicates that IL-4 modulates expression of IL-1beta mRNA and protein and that it attenuates IL-1beta-induced impairment of LTP and phosphorylation of JNK and c-Jun. We argued that, if a decrease in hippocampal IL-4 concentration significantly contributed to the age-related impairment in LTP, then restoration of IL-4 should restore LTP. To test this, we treated rats with VP015 (phospholipid microparticles-incorporating phosphatidylserine), which increases IL-4 concentration in hippocampus. The data indicate that the VP015-induced increase in IL-4 concentration in hippocampus of aged rats and lipopolysaccharide (LPS)-treated rats was accompanied by a reversal of the age-related and LPS-induced impairment in LTP in perforant path granule cell synapses. We propose that interplay between pro-inflammatory and anti-inflammatory responses impact significantly on synaptic function in the hippocampus of the aged rat. 相似文献
65.
Rukamp BJ Kam CM Natarajan S Bolton BW Smyth MJ Kelly JM Powers JC 《Archives of biochemistry and biophysics》2004,422(1):9-22
Granzyme M is a member of a family of granule serine proteases that participate in target cell death initiated by cytotoxic lymphocytes. The enzyme is almost exclusively expressed in NK cell types. Granzyme M cleaves at the carboxy side of amino acids with long, hydrophobic side chains like Met, Leu, and Nle. To further study the substrate specificity of the enzyme, a series of peptide thiobenzyl esters was synthesized. The hydrolysis of the substrates with murine and human recombinant forms of granzyme M was observed. The results show that the enzyme has a strong preference for Pro at the P2 position and Ala, Ser, or Asp at the P3 position. These results suggest that the protein residues of the S2 and S3 subsites form important binding interactions that aid in the selection of specific natural substrates for granzyme M. A series of inhibitors was also tested with granzyme M. None of the inhibitors were effective inactivators of granzyme M, including the general serine protease inhibitor, 3,4-dichloroisocoumarin, which is usually a potent inactivator of serine proteases. This suggests that inhibition of granzyme M may be difficult. Also reported for the first time is the method utilized to isolate granzyme M used in this and previous publications. The observations in this paper will be valuable in development of new potent inhibitors for granzyme M as well as assist in determining the biological function of the enzyme. 相似文献
66.
Questions: Do species planted outdoors in native soil differ in the timing of their period of vegetative spread during the growing season? Location: Cleish Hills, Fife, Scotland, UK. Methods: Patches (20 cm × 20 cm) of Agrostis capillaris, Festuca rubra, Holcus lanatus, Lolium perenne and Poa trivialis were arranged in plots so that every species patch had all the remaining species as neighbours. The plots were cut every 14 days at 3 cm and photographed monthly from above. The photographs of species boundaries were traced and digitised. Measurements were made on the digitised images of the distances each species spread and of the area occupied by each species. Results: Fitting some simple models to the data indicated firstly that species varied in their vegetative competitive ability, with A. capillaris and P. trivialis being the most and least competitive respectively, and secondly that the ability of a species to colonize can differ from its ability to resist colonization, the most discrepant species being H. lanatus. Our analysis also indicated statistically significant variation in the data over and above the simple models, providing evidence of additional, genuine, complexity in the seasonal patterns of spread. Conclusion: This study provides evidence to support the hypothesis that clonal grass species do not spread vegetatively at the same times within a growing season. Since sward height is known to affect species spread, there is some opportunity for the manipulation of species composition simply through temporal control of sward height. 相似文献
67.
Interstitial cells of Cajal (ICCs) freshly isolated from rabbit portal vein and loaded with the Ca(2+)-sensitive indicator fluo-3 revealed rhythmical [Ca(2+)](i) changes occurring at 0.02-0.1 Hz. Each increase in [Ca(2+)](i) originated from a discrete central region of the ICC and propagated as a [Ca(2+)](i) wave towards the cell periphery, but usually became attenuated before reaching the ends of the cell. In about 40% of ICCs each rhythmical change in [Ca(2+)](i) consisted of an initial [Ca(2+)](i) increase (phase 1) followed by a faster rise in [Ca(2+)](i) (phase 2) and then a decrease in [Ca(2+)](i) (phase 3); the frequency correlated with the rate of rise of [Ca(2+)](i) during phase 1, but not with the peak amplitude. Rhythmical [Ca(2+)](i) changes persisted in nicardipine, but were abolished in Ca(2+)-free solution as well as by SK&F96365, cyclopiazonic acid, thapsigargin, 2-APB, xestospongin C or ryanodine. Intracellular Ca(2+) stores visualised with the low-affinity Ca(2+) indicator fluo-3FF were found to be enriched with ryanodine receptors (RyRs) detected with BODIPY TR-X ryanodine. Rhythmical [Ca(2+)](i) changes originated from a perinuclear S/ER element showing the highest RyR density. Immunostaining with anti-TRPC3,6,7 antibodies revealed the expression of these channel proteins in the ICC plasmalemma. This suggests that these rhythmical [Ca(2+)](i) changes, a key element of ICC pacemaking activity, result from S/ER Ca(2+) release which is mediated via RyRs and IP(3) receptors and is modulated by the activity of S/ER-Ca(2+)-ATPase and TRP channels but not by L-type Ca(2+) channels. 相似文献
68.
69.
Bolton MD Secor GA Rivera V Weiland JJ Rudolph K Birla K Rengifo J Campbell LG 《Fungal biology》2012,116(4):511-521
Cercospora leaf spot, caused by the hemibiotrophic fungal pathogen Cercospora beticola, is the most economically damaging foliar disease of sugarbeet worldwide. Although most C. beticola populations display characteristics reminiscent of sexual recombination, no teleomorph has been described. To assess whether populations in northern United States have characteristics consistent with sexual reproduction, 1024 isolates collected over a 3-y period were analyzed for frequency and distribution of mating type genes. After clone correction, an approximately equal distribution of mating types was found for each sampling year. Mating type frequency was also assessed in individual lesions. Lesions always consisted of isolates with a single mating type and microsatellite haplotype, but both mating types and up to five microsatellite haplotypes could be found on an individual leaf. The MAT1-1-1 and MAT1-2-1 genes were sequenced from 28 MAT1-1 and 28 MAT1-2 isolates, respectively. Three MAT1-1-1 nucleotide haplotypes were identified that encoded a single amino acid sequence. For MAT1-2-1, five nucleotide haplotypes were identified that encoded four protein variants. MAT1-1-1 and MAT1-2-1 gene expression analyses were conducted on plants inoculated with either or both mating types. MAT1-1-1 expression remained low, but MAT1-2-1 spiked during late stages of colonization. A segment of the MAT1-2-1 coding sequence was also found in MAT1-1 isolates. Taken together, these results suggest that C. beticola has the potential for sexual reproduction. 相似文献
70.
Lipoteichoic acid is an important microbe-associated molecular pattern of Lactobacillus rhamnosus GG
Claes Ingmar JJ Segers Marijke E Verhoeven Tine LA Dusselier Michiel Sels Bert F De Keersmaecker Sigrid CJ Vanderleyden Jos Lebeer Sarah 《Microbial cell factories》2012,11(1):1-8