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Induced adaptive and cross-protective responses to peroxide stress are important strategies used by bacteria to survive stressful environments. We have shown that exposure to low levels of peroxide (adaptive) and superoxide anions (cross-protection) induced high levels of resistance to peroxide killing in Agrobacterium tumefaciens. The mechanisms and genes involved in these processes have not been identified. Here, the roles played by peroxide (oxyR) and superoxide (soxR) global regulators and a catalase gene (katA) during these responses were investigated. H 2 O 2 -induced adaptive protection was completely abolished in both the oxyR and katA mutants. Superoxide generator (menadione)-induced cross-protection to H 2 O 2 killing was observed in a soxR mutant, but not in either an oxyR or a katA mutant. In vivo analysis of the katA promoter, using a katA: :lacZ transcriptional fusion, revealed that it could be induced by menadione in an oxyR-dependent manner. These results lead us to conclude that H 2 O 2 and superoxide anions directly or indirectly oxidize OxyR and it is the resulting activation of katA expression that is responsible for the induced protection against lethal concentrations of H 2 O 2 .

This study identified norovirus in children presenting with acute gastroenteritis and determined the capsid genotypes of the circulating norovirus strains in multiple regions in Thailand during October 2004 to December 2006 and March 2008 to August 2010. A total of 7,420 stool samples were collected from both cases (3621) and controls (3799). The stool samples were screened by two real-time RT-PCR assays to detect genogroup I and genogroup II noroviruses. Norovirus-positive samples were identified in 516 cases (14.3%) and 181 controls (4.8%) with more than half of norovirus positive samples from 7-24 months old children. Positive samples were sequenced and genotyped for the capsid gene. GII.4 was the genotype observed most frequently (56.4%) followed by GII.3 (28.2%). Five peaks of infection were observed, with predominant capsid genotypes that alternated during the surveillance periods between GII.4 and GII.3. Analyses of positive samples showed variation in genotype from each region as well as from different study periods. This emphasizes the importance of multi-site studies to investigate norovirus epidemiology. Additionally, the observed regional and temporal variations suggest that a systematic nation-wide surveillance effort in Thailand is needed to track the continually changing norovirus epidemiology.

With TAC, pathogen load can be estimated from the amount of nucleic acid present for each pathogen, which can be analyzed further to better determine pathogen attribution and to compare pathogen load between case and control samples. Unfortunately, such correlative analysis was not possible because of the limited sample size available in this study. A larger sample size is needed for further evaluation of TAC on a specific population set, including military personnel. Regardless, TAC was found to be a useful and functional diagnostic platform that is less time-consuming, easy to use with high reproducibility, and costs less per sample compared to the current typically employed methods. The successful application of TAC in acute diarrhea stool samples from a US military population in the Philippines demonstrates its versatility as a potential candidate for a next-generation diagnostics platform.