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Correlations between Shine-Dalgarno Sequences and Gene Features Such as Predicted Expression Levels and Operon Structures. Jiong Ma, 2002.This work assesses relationships for 30 complete prokaryotic genomes between the presence of the Shine-Dalgarno (SD) sequence and other gene features, including expression levels, type of start codon, and distance between successive genes . A significant positive correlation of the presence of an SD sequence and the predicted expression level of a gene based on codon usage biases was ascertained, such that predicted highly expressed genes are more likely to possess a strong SD sequence than average genes . Genes with AUG start codons are more likely than genes with other start codons, GUG or UUG, to possess an SD sequence . Genes in close proximity to upstream genes on the same coding strand in most genomes are significantly higher in SD presence . In light of these results, we discuss the role of the SD sequence in translation initiation and its relationship with predicted gene expression levels and with operon structure in both bacterial and archaeal genomes . Adhesive Surface Proteins of Erysipelothrix rhusiopathiae Bind to Polystyrene, Fibronectin, and Type I and IV Collagens. Yoshihiro Shimoji, 2003.Erysipelothrix rhusiopathiae is a gram-positive bacterium that causes erysipelas in animals and erysipeloid in humans . We found two adhesive surface proteins of E . rhusiopathiae and determined the nucleotide sequences of the genes, which were colocalized and designated rspA and rspB . The two genes were present in all of the serovars of E . rhusiopathiae strains examined . The deduced RspA and RspB proteins contain the C-terminal anchoring motif, LPXTG, which is preceded by repeats of consensus amino acid sequences . The consensus sequences are composed of 78 to 92 amino acids and repeat 16 and 3 times in RspA and RspB, respectively . Adhesive surface proteins of other gram-positive bacteria, including Listeria monocytogenes adhesin-like protein, Streptococcus pyogenes protein F2 and F2-like protein, Streptococcus dysgalactiae FnBB, and Staphylococcus aureus Cna, share the same consensus repeats . Furthermore, the N-terminal regions of RspA and RspB showed characteristics of the collagen-binding domain that was described for Cna . RspA and RspB were expressed in Escherichia coli as histidine-tagged fusion proteins and purified . The recombinant proteins showed a high degree of capacity to bind to polystyrene and inhibited the binding of E . rhusiopathiae onto the abiotic surface in a dose dependent manner . In a solid-phase binding assay, both of the recombinant proteins bound to fibronectin, type I and IV collagens, indicating broad spectrum of their binding ability . It was suggested that both RspA and RspB were exposed on the cell surface of E . rhusiopathiae, as were the bacterial cells agglutinated by the anti-RspA immunoglobulin G (IgG) and anti-RspB IgG . RspA and RspB were present both in surface-antigen extracts and the culture supernatants of E . rhusiopathiae Fujisawa-SmR (serovar 1a) and SE-9 (serovar 2) . The recombinant RspA, but not RspB, elicited protection in mice against experimental challenge . These results suggest that RspA and RspB participate in initiation of biofilm formation through their binding abilities to abiotic and biotic surfaces . Characterization of Anaplasma marginale Isolated from North American Bison. José de la Fuente, 2003.Anaplasma marginale (Rickettsiales: Anaplasmataceae), a tick-borne pathogen of cattle, is endemic in tropical and subtropical regions of the world . Although serologic tests have identified American bison, Bison bison, as being infected with A . marginale, the present study was undertaken to confirm A . marginale infection and to characterize isolates obtained from naturally infected bison in the United States and Canada . Major surface protein (MSP1a and MSP4) sequences of bison isolates were characterized in comparison with New World cattle isolates . Blood from one U.S . bison was inoculated into a susceptible, splenectomized calf, which developed acute anaplasmosis, demonstrating infectivity of this A . marginale bison isolate for cattle . The results of this study showed that these A . marginale isolates obtained from bison were similar to ones from naturally infected cattle .
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