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The trans-Acting Protein Interacting with the DNA Motif Proximal to the Transcriptional Start Site of Plant L-Asparaginase Is Bacterial Sarcosine Oxidase. William T. Jones, 2004.A trans-acting protein interacting with a specific sequence motif proximal to the transcriptional start site of the L-asparaginase promoter has been observed previously (E . Vincze, J . M . Reeves, E . Lamping, K . J . F . Farnden, and P . H . S . Reynolds, Plant Mol . Biol . 26:303-311, 1994) . Gel retardation experiments in which protein extracts of Mesorhizobium loti and developing nodules were used suggested a bacterial origin for the repressor binding protein (rep2037) . Nodulation tests were performed by using different Fix- Tn5 mutants of M . loti. Analyses of these mutants revealed a correlation between the presence of Mesorhizobium in the nodule-like structures and the ability of nodule protein extracts to bind the repressor binding domain (RBD) . Through the use of mutated RBD sequences, the RBD sequence was identified as CTAAAAT . The repressor protein was isolated from M . loti NZP2037 by multiple chromatographic procedures and affinity separation by using concatemers of RBD attached to magnetic beads . Sequencing of the recovered protein resulted in identification of the repressor protein as the sarcosine oxidase 
subunit . This was confirmed by expression of the gene encoding the
M . loti
subunit of sarcosine oxidase in Escherichia coli. When the
expressed peptide was bound to RBD, the gel retardation result was
identical to the result obtained with rep2037 from M . loti
strain NZP2037 .
Pseudomonas aeruginosa LasA Protease in Treatment of Experimental Staphylococcal Keratitis. Irina S. Barequet, 2004.LasA protease is a staphylolytic endopeptidase secreted by Pseudomonas aeruginosa . We have examined the effectiveness of LasA protease in the treatment of staphylococcal keratitis caused by methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S . aureus (MRSA) isolates in a rabbit model . Keratitis was induced by intrastromal injection of the bacteria . The eyes were treated topically, and the efficacy of LasA protease was compared to those of lysostaphin (a staphylolytic protease secreted by Staphylococcus simulans) and vancomycin . When treatment was initiated early (4 h) after infection, practically all of the MSSA- and MRSA-infected corneas were sterilized by LasA protease, and its efficacy in eradicating the bacteria was comparable to those of lysostaphin and vancomycin . By contrast, most of the control corneas were heavily infected, with median values of 4.5 x 106 (MSSA) and 5 x 105 (MRSA) CFU/cornea (P < 0.001) . When treatment was initiated late (10 h) after infection, LasA protease reduced the numbers of CFU in both MSSA- and MRSA-infected corneas by 3 to 4 orders of magnitude compared to the numbers of CFU for the controls (median values, 1,380 and 30 CFU/cornea, respectively, for the treated animals compared to 1.2 x 106 and 5 x 105 CFU/cornea for the respective controls [P = 0.001]), and it was more effective than vancomycin in eradicating MRSA cells (P = 0.02) . In both the early- and the late-treatment protocols, the clinical scores for eyes treated with LasA protease were significantly lower than those for the eyes of the corresponding controls and comparable to those for the lysostaphin- and vancomycin-treated eyes . We conclude that LasA protease is effective in the treatment of experimental S . aureus keratitis in rabbits and may have potential for the treatment of disease in humans . Nonmarine Crenarchaeol in Nevada Hot Springs. A. Pearson, 2004.Glycerol dialkyl glycerol tetraethers (GDGTs) are core membrane lipids of the Crenarchaeota . The structurally unusual GDGT crenarchaeol has been proposed as a taxonomically specific biomarker for the marine planktonic group I archaea . It is found ubiquitously in the marine water column and in sediments . In this work, samples of microbial community biomass were obtained from several alkaline and neutral-pH hot springs in Nevada, United States . Lipid extracts of these samples were analyzed by high-performance liquid chromatography-mass spectrometry and by gas chromatography-mass spectrometry . Each sample contained GDGTs, and among these compounds was crenarchaeol . The distribution of archaeal lipids in Nevada hot springs did not appear to correlate with temperature, as has been observed in the marine environment . Instead, a significant correlation with the concentration of bicarbonate was observed . Archaeal DNA was analyzed by denaturing gradient gel electrophoresis . All samples contained 16S rRNA gene sequences which were more strongly related to thermophilic crenarchaeota than to Cenarchaeum symbiosum, a marine nonthermophilic crenarchaeon . The occurrence of crenarchaeol in environments containing sequences affiliated with thermophilic crenarchaeota suggests a wide phenotypic distribution of this compound . The results also indicate that crenarchaeol can no longer be considered an exclusive biomarker for marine species . Overrepresentation of a Gene Family Encoding Extracytoplasmic Solute Receptors in Bordetella. Rudy Antoine, 2003.A family of genes that are likely to encode extracytoplasmic solute receptors is strongly overrepresented in several ß-proteobacteria, including Bordetella pertussis . This gene family, of which members have been called bug genes, contains some examples that are contained within polycistronic operons coding for tripartite uptake transporters of the TTT family, while the vast majority are "orphan" genes . Proteomic and functional analyses demonstrated that several of these genes are expressed in B . pertussis, and one is involved in citrate uptake . The bug genes probably form an ancient family that has been subjected to a large expansion in a restricted phylogenic group .
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