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Efficacy of Organic Acids in Hand Cleansers for Prevention of Rhinovirus Infections. Ronald B. Turner, 2004.Direct hand-to-hand contact is an important mechanism of transmission of rhinovirus infection . The rhinoviruses are inactivated at a low pH . A survey of organic acids in vitro revealed that these compounds have antirhinoviral activity that persists for at least 3 h after application to the skin . In additional studies of salicylic acid (SA) and pyroglutamic acid (PGA), the hands of volunteers were contaminated with rhinovirus at defined times after application of the acid, and then volunteers attempted to inoculate the nasal mucosa with one hand and quantitative viral cultures were done on the other hand . In one study, 3.5% SA or 1% SA with 3.5% PGA was compared with controls 15 min after application to assess the efficacy of the inactivation of virus and prevention of infection . Virus was recovered from the hands of 28 out of 31 (90%) of the volunteers in the control group compared to 4 out of 27 (15%) and 0 out of 27 in the groups administered 3.5 and 1% SA, respectively (P < 0.05) . Rhinovirus infection occurred in 10 out of 31 (32%) of the controls and 2 out of 27 (7%) of volunteers in both treatment groups (P < 0.05 compared with control) . In a second study, the efficacy of 4% PGA was evaluated 15 min, 1 h, and 3 h after application . Significantly fewer volunteers had positive hand cultures at all time points compared with the control group, but the proportion that developed rhinovirus infection was not significantly reduced . These results suggest the feasibility of the prevention of rhinovirus transmission by hand treatments that are virucidal on contact and have activity that persists after application . Biomass Content Governs Fermentation Rate in Nitrogen-Deficient Wine Musts. Cristian Varela, 2004.Problematic fermentations are common in the wine industry . Assimilable nitrogen deficiency is the most prevalent cause of sluggish fermentations and can reduce fermentation rates significantly . A lack of nitrogen diminishes a yeast's metabolic activity, as well as the biomass yield, although it has not been clear which of these two interdependent factors is more significant in sluggish fermentations . Under winemaking conditions with different initial nitrogen concentrations, metabolic flux analysis was used to isolate the effects . We quantified yeast physiology and identified key metabolic fluxes . We also performed cell concentration experiments to establish how biomass yield affects the fermentation rate . Intracellular analysis showed that trehalose accumulation, which is highly correlated with ethanol production, could be responsible for sustaining cell viability in nitrogen-poor musts independent of the initial assimilable nitrogen content . Other than the higher initial maintenance costs in sluggish fermentations, the main difference between normal and sluggish fermentations was that the metabolic flux distributions in nitrogen-deficient cultures revealed that the specific sugar uptake rate was substantially lower . The results of cell concentration experiments, however, showed that in spite of lower sugar uptake, adding biomass from sluggish cultures not only reduced the time to finish a problematic fermentation but also was less likely to affect the quality of the resulting wine as it did not alter the chemistry of the must . A Second PDZ-Containing Serine Protease Contributes to Activation of the Sporulation Transcription Factor  K in Bacillus subtilis.Qi Pan, 2003.Gene expression late during the process of sporulation in Bacillus subtilis is governed by a multistep, signal transduction pathway involving the transcription factor K, which is derived by regulated proteolysis from the inactive proprotein pro-K . Processing of pro-K is triggered by a signaling protein known as SpoIVB, a serine protease that contains a region with similarity to the PDZ family of protein-protein interaction domains . Here we report the discovery of a second PDZ-containing serine protease called CtpB that contributes to the activation of the pro-K processing pathway . CtpB is a sporulation-specific, carboxyl-terminal processing protease and shares several features with SpoIVB . We propose that CtpB acts to fine-tune the regulation of pro-K processing, and we discuss possible models by which CtpB influences the
K activation pathway .
In Vitro Properties of RpoS (  S) Mutants of Escherichia coli with Postulated N-Terminal Subregion 1.1 or C-Terminal Region 4 Deleted.J. Gowrishankar, 2003.Derivatives of the stationary-phase sigma factor S of Escherichia coli lacking either of two conserved domains, the postulated N-terminal subregion 1.1 or the C-terminal region 4, were shown to be competent in vitro for transcription initiation from several
S-dependent promoters on supercoiled DNA templates . Unlike wild-type
S, however, the deletion derivatives were inactive on relaxed templates . The anomalous slow electrophoretic mobility of
S on denaturing gels was corrected by deletion of subregion 1.1, suggesting that this domain in
S may be structurally and functionally analogous to subregion 1.1 of
70, substitutions in which have previously been shown to rectify the anomalous electrophoretic migration of
70 (V . Gopal and D . Chatterji, Eur . J . Biochem . 244:614-618, 1997) .
Overexpression of groESL in Clostridium acetobutylicum Results in Increased Solvent Production and Tolerance, Prolonged Metabolism, and Changes in the Cell's Transcriptional Program. Christopher A. Tomas, 2003.DNA array and Western analyses were used to examine the effects of groESL overexpression and host-plasmid interactions on solvent production in Clostridium acetobutylicum ATCC 824 . Strain 824(pGROE1) was created to overexpress the groESL operon genes from a clostridial thiolase promoter . The growth of 824(pGROE1) was inhibited up to 85% less by a butanol challenge than that of the control strain, 824(pSOS95del) . Overexpression of groESL resulted in increased final solvent titers 40% and 33% higher than those of the wild type and plasmid control strains, respectively . Active metabolism lasted two and one half times longer in 824(pGROE1) than in the wild type . Transcriptional analysis of 824(pGROE1) revealed increased expression of motility and chemotaxis genes and a decrease in the expression of the other major stress response genes . Decreased expression of the dnaKJ operon upon overexpression of groESL suggests that groESL functions as a modulator of the CIRCE regulon, which is shown here to include the hsp90 gene . Analysis of the plasmid control strain 824(pSOS95del) revealed complex host-plasmid interactions relative to the wild-type strain, resulting in prolonged biphasic growth and metabolism . Decreased expression of four DNA gyrases resulted in differential expression of many key primary metabolism genes . The ftsA and ftsZ genes were expressed at higher levels in 824(pSOS95del), revealing an altered cell division and sporulation pattern . Both transcriptional and Western analyses revealed elevated stress protein expression in the plasmid-carrying strain .
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