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Update of the Standard Numbering Scheme for Class B ß-Lactamases. Gianpiero Garau, 2004. Localization of UvrA and Effect of DNA Damage on the Chromosome of Bacillus subtilis. Bradley T. Smith, 2002. Genome Sequence and Analysis of the Oral Bacterium Fusobacterium nucleatum Strain ATCC 25586. Vinayak Kapatral, 2002.We present a complete DNA sequence and metabolic analysis of the dominant oral bacterium Fusobacterium nucleatum . Although not considered a major dental pathogen on its own, this anaerobe facilitates the aggregation and establishment of several other species including the dental pathogens Porphyromonas gingivalis and Bacteroides forsythus . The F . nucleatum strain ATCC 25586 genome was assembled from shotgun sequences and analyzed using the ERGO bioinformatics suite (http://www.integratedgenomics.com) . The genome contains 2.17 Mb encoding 2,067 open reading frames, organized on a single circular chromosome with 27% GC content . Despite its taxonomic position among the gram-negative bacteria, several features of its core metabolism are similar to that of gram-positive Clostridium spp., Enterococcus spp., and Lactococcus spp . The genome analysis has revealed several key aspects of the pathways of organic acid, amino acid, carbohydrate, and lipid metabolism . Nine very-high-molecular-weight outer membrane proteins are predicted from the sequence, none of which has been reported in the literature . More than 137 transporters for the uptake of a variety of substrates such as peptides, sugars, metal ions, and cofactors have been identified . Biosynthetic pathways exist for only three amino acids: glutamate, aspartate, and asparagine . The remaining amino acids are imported as such or as di- or oligopeptides that are subsequently degraded in the cytoplasm . A principal source of energy appears to be the fermentation of glutamate to butyrate . Additionally, desulfuration of cysteine and methionine yields ammonia, H2S, methyl mercaptan, and butyrate, which are capable of arresting fibroblast growth, thus preventing wound healing and aiding penetration of the gingival epithelium . The metabolic capabilities of F . nucleatum revealed by its genome are therefore consistent with its specialized niche in the mouth . Characterization of Escherichia coli O157:H7 from Downer and Healthy Dairy Cattle in the Upper Midwest Region of the United States. C. M. Byrne, 2003.While cattle in general have been identified as a reservoir of Escherichia coli O157:H7, there are limited data regarding the prevalence and clonality of this pathogen in downer dairy cattle and the potential impact to human health that may occur following consumption of meat derived from downer dairy cattle . In the present study, conducted at two slaughter facilities in Wisconsin between May and October of 2001, we established a higher prevalence of E . coli O157:H7 in fecal and/or tissue samples obtained aseptically from intact colons of downer dairy cattle (10 of 203, 4.9%) than in those from healthy dairy cattle (3 of 201, 1.5%) . Analyses of 57 isolates, representing these 13 positive samples (one to five isolates per sample), by pulsed-field gel electrophoresis, revealed 13 distinct XbaI restriction endonuclease digestion profiles (REDP) . Typically, isolates from different animals displayed distinct REDP and isolates from the same fecal or colon sample displayed indistinguishable REDP . However, in one sample, two different, but highly related, REDP were displayed by the isolates recovered . Antimicrobial susceptibility testing indicated that 10 of the 57 isolates, recovered from 2 (1 downer and 1 healthy animal) of the 13 positive samples, were resistant to at least 1 of 18 antimicrobials tested . However, there was no appreciable difference in the frequency of resistance of isolates recovered from downer and healthy dairy cattle, and not all isolates with the same REDP displayed the same antimicrobial susceptibility profile . Lastly, it was not possible to distinguish between isolates recovered from downer and healthy cattle based on their XbaI REDP or antimicrobial susceptibility . These results indicate that downer cattle had a 3.3-fold-higher prevalence of E . coli O157:H7 than healthy cattle within the time frame and geographic scope of this study .
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