Identification and characterization of expression mechanism of a multidrug-resistant operon (lmr) newly found in Bacillus subtilis genome sequencing analysis of the 22 - 25 degree region

A 32-kb nucleotide sequence in the region of the lincomycin-resistence gene, located from 22°to 25°on the Bacillus subtilis chromosome, was determined. Thirty two putative open reading frames (ORF_s) were identified in this region, and this regionseems to be rich in membrane proteins, since at least 16 gene products appeared to contain membrane-spanning domains.I mapped and identified the site of the lin-2 mutation (two nucleotide replacements) by sequencing. This site is lacated between a putative promoter and the SD sequence of lmrA (yccB) [a putative regulatory gene of the lmr operon, which consists of lmrA and lmrB (yccA)]. LmrB is a homologue of proteins involved in drug-export systems and seems likely to be the protein responsible for resistance to lincomycin. The lincomycin-resistemt mutant is also resistant to puromycin, rhodamine 6G, norfloxacin, and tosufloxacin.To analyze the machanism of acquired lincomycin resistence, I isolated 19 lincomycin-resistent mutants expressing lmrB, and compared nucleotide sequences at lmrA and its flanking regions in the mutants with those of the lin-2 lincomycin-resistantstrain, B. subtilis 1A221 (Bacillus Genetic Stock Center) and of the wold type strain, 168. All but one of the mutation sites of 18 mutants and of 1A221 were located at two regions (-3 to -1 and +15) immediatelydownstream of the -10 region of the lmrpromoter. These mutations at one or both sites increased lmr transcription activity in vivo and in vitro. The mechanism of lmr expression is a novel system, which differs from other typical expression mechanisms of multidrug resistance genes.Thesis (Ph. D. in Science)--University of Tsukuba, (A), no. 3072, 2003.3.25Includes bibliographical references枯草菌染色体２２度～２５度のゲノム解析に基づく新規多剤耐性遺伝子オペロン（lmr）の同定と発現機構の解析 ~ 熊野、みゆ

A Novel Methodology to Evaluate Health Impacts Caused by VOC Exposures Using Real-Time VOC and Holter Monitors

While various volatile organic compounds (VOCs) are known to show neurotoxic effects, the detailed mechanisms of the action of VOCs on the autonomic nervous system are not fully understood, partially because objective and quantitative measures to indicate neural abnormalities are still under development. Nevertheless, heart rate variability (HRV) has been recently proposed as an indicative measure of the autonomic effects. In this study, we used HRV as an indicative measure of the autonomic effrects to relate their values to the personal concentrations of VOCs measured by a real-time VOC monitor. The measurements were conducted for 24 hours on seven healthy subjects under usual daily life conditions. The results showed HF powers were significantly decreased for six subjects when the changes of total volatile organic compound (TVOC) concentrations were large, indicating a suppression of parasympathetic nervous activity induced by the exposure to VOCs. The present study indicated these real-time monitoring was useful to characterize the trends of VOC exposures and their effects on autonomic nervous system

Lincomycin Resistance Mutations in Two Regions Immediately Downstream of the −10 Region of lmr Promoter Cause Overexpression of a Putative Multidrug Efflux Pump in Bacillus subtilis Mutants

We isolated 19 lincomycin-resistant Bacillus subtilis mutants by expressing lmrB encoding a putative multidrug efflux protein. Eighteen of the mutants altered at two regions (−3 to −1 and +15) immediately downstream of the −10 region of the lmr promoter increased lmr transcription in vivo and in vitro

In-situ Real-Time Monitoring of Volatile Organic Compound Exposure and Heart Rate Variability for Patients with Multiple Chemical Sensitivity

In-situ real-time monitoring of volatile organic compound (VOC) exposure and heart rate variability (HRV) were conducted for eight multiple chemical sensitivity (MCS) patients using a VOC monitor, a Holter monitor, and a time-activity questionnaire for 24 h to identify the relationship between VOC exposure, biological effects, and subjective symptoms in actual life. The results revealed no significantly different parameters for averaged values such as VOC concentration, HF (high frequency), and LF (low frequency) to HF ratio compared with previous data from healthy subjects (Int. J. Environ. Res. Public Health 2010, 7, 4127–4138). Significant negative correlations for four subjects were observed between HF and amounts of VOC change. These results suggest that some patients show inhibition of parasympathetic activities along with VOC exposure as observed in healthy subjects. Comparing the parameters during subjective symptoms and normal condition, VOC concentration and/or VOC change were high except for one subject. HF values were low for five subjects during subjective symptoms. Examining the time-series data for VOC exposure and HF of each subject showed that the subjective symptoms, VOC exposure, and HF seemed well related in some symptoms. Based on these characteristics, prevention measures of symptoms for each subject may be proposed

Methicillin-Resistant Staphylococcus saprophyticus Isolates Carrying Staphylococcal Cassette Chromosome mec Have Emerged in Urogenital Tract Infections▿

Staphylococcus saprophyticus is a uropathogenic bacterium that causes acute uncomplicated urinary tract infections, particularly in female outpatients. We investigated the dissemination and antimicrobial susceptibilities of 101 S. saprophyticus isolates from the genitourinary tracts of patients in Japan. Eight of these isolates were mecA positive and showed β-lactam resistance. Pulsed-field gel electrophoresis showed that only some isolates were isogenic, indicating that the mecA gene was apparently acquired independently by mecA-positive isolates through staphylococcal cassette chromosome mec (SCCmec). Type determination of SCCmec by multiplex PCR showed a nontypeable element in the eight mecA-positive isolates. Sequence analysis of the entire SCCmec element from a prototype S. saprophyticus strain revealed that it was nontypeable with the current SCCmec classification due to the novel composition of the class A mec gene complex (IS431-mecA-mecR1-mecI genes) and the ccrA1/ccrB3 gene complex. Intriguingly, the attachment sites of SCCmec are similar to those of type I SCCmec in S. aureus NCTC 10442. Furthermore, the genes around the mec gene complex are similar to those of type II/III SCCmec in S. aureus, while those around the ccr gene complex are similar to those of SCC15305RM found in S. saprophyticus ATCC 15305. In comparison with known SCCmec elements, this S. saprophyticus SCCmec is a novel type