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Identification of Two myo-Inositol Transporter Genes of Bacillus subtilis. Ken-Ichi Yoshida, 2002.Among hundreds of mutants constructed systematically by the Japanese groups participating in the functional analysis of the Bacillus subtilis genome project, we found that a mutant with inactivation of iolT (ydjK) exhibited a growth defect on myo-inositol as the sole carbon source . The putative product of iolT exhibits significant similarity with many bacterial sugar transporters in the databases . In B . subtilis, the iolABCDEFGHIJ and iolRS operons are known to be involved in inositol utilization, and its transcription is regulated by the IolR repressor and induced by inositol . Among the iol genes, iolF was predicted to encode an inositol transporter . Inactivation of iolF alone did not cause such an obvious growth defect on inositol as the iolT inactivation, while simultaneous inactivation of the two genes led to a more severe defect than the single iolT inactivation . Determination of inositol uptake by the mutants revealed that iolT inactivation almost completely abolished uptake, but uptake by IolF itself was slightly detectable . These results, as well as the Km and Vmax values for the IolT and IolF inositol transporters, indicated that iolT and iolF encode major and minor inositol transporters, respectively . Northern and primer extension analyses of iolT transcription revealed that the gene is monocistronically transcribed from a promoter likely recognized by  sgr;A RNA polymerase and negatively regulated by IolR as well . The interaction between IolR and the iolT promoter region was analyzed by means of gel retardation and DNase I footprinting experiments, it being suggested that the mode of interaction is quite similar to that found for the promoter regions of the iol divergon .
Presence of Viral Genomes in Mineral Water: a Sufficient Condition To Assume Infectious Risk?. Benoît Gassilloud, 2003.Appropriate interpretation of a positive reverse transcription-PCR is an important issue for virus-related health hazard assessment because viral genomes and infectious viruses exhibit different behavior patterns in water . In this context, using Poliovirus 1 and Feline calicivirus f9 as examples of enteric viruses, first we demonstrated that the stability of infectious viruses is greatly affected by the temperature of mineral water (10, 20, and 35°C) and that, in contrast, temperature has little effect on the corresponding genomes . Second, we demonstrated that infectious particles are degraded more rapidly than viral genomes at all temperatures studied . At 35°C, Poliovirus 1 infectivity was reduced 4 logs after only 19 days, while an equivalent reduction would have taken 75 years (according to the model applied) for the viral genome . Contradictory conclusions can also be drawn concerning the sensitivity of viral serotypes depending on whether the infectious virus or the viral genome is considered . The Feline calicivirus f9 genome is more resistant than the Poliovirus 1 genome, whereas the opposite is true for the corresponding infectious viruses . Thus, we concluded that a positive test for a viral genome in mineral water must be interpreted with utmost caution because of the lack of a correlation between the presence of viral genomes and viral infectivity . Detection of viral genomes may be necessary to identify infectious risk for the human population, but it cannot be considered sufficient .
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