The see more present study does not limit the function of the Cls1 backup system to acute low-pH stress. This study was supported in part by the Program to Disseminate Tenure Tracking System, MEXT, Japan (to RLO). R.L.O. and K.K. contributed equally to the work. “
“5′-Methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) plays crucial roles in the production of autoinducers and methionine metabolism. Putative genes encoding MTAN and AdoHcyase from Burkholderia

thailandensis were cloned and characterized. The Km values of MTAN for 5′-methylthioadenosine (MTA) and S-adenosylhomocysteine (SAH) were 19 and 58 μM, respectively. The catalytic efficiency of MTAN for SAH was only 0.004% of the value for MTA, indicating an almost complete substrate preference of MTAN for MTA. The results of autoinducer-2 assay of B. thailandensis and recombinants indicated that LuxS enzyme activity was lacking in Burkholderia species. Instead, AdoHcyase hydrolysed SAH directly to homocysteine and adenosine in the activated methyl cycle. Meanwhile, the Km value of AdoHcyase for SAH was determined to be 40 μM. Sequence analysis revealed that MTAN had much higher diversity than AdoHcyase, which likely contributes to its substrate preference for MTA. Furthermore, the 5FU phylogenetic tree of MTAN sequences revealed that LuxS+ bacteria could be discriminated from LuxS− bacteria. These results suggested that the substrate preference of MTAN for MTA and SAH degradation

pathway evolved with the bacterial-activated methyl cycle. “
“The need for improved rapid diagnostic tests selleck screening library for tuberculosis disease has prompted interest in the volatile organic compounds (VOCs) emitted by Mycobacterium tuberculosis complex bacteria. We have

investigated VOCs emitted by Mycobacterium bovis BCG grown on Lowenstein–Jensen media using selected ion flow tube mass spectrometry and thermal desorption-gas chromatography-mass spectrometry. Compounds observed included dimethyl sulphide, 3-methyl-1-butanol, 2-methyl-1-propanol, butanone, 2-methyl-1-butanol, methyl 2-methylbutanoate, 2-phenylethanol and hydrogen sulphide. Changes in levels of acetaldehyde, methanol and ammonia were also observed. The compounds identified are not unique to M. bovis BCG, and further studies are needed to validate their diagnostic value. Investigations using an ultra-rapid gas chromatograph with a surface acoustic wave sensor (zNose) demonstrated the presence of 2-phenylethanol (PEA) in the headspace of cultures of M. bovis BCG and Mycobacterium smegmatis, when grown on Lowenstein–Jensen supplemented with glycerol. PEA is a reversible inhibitor of DNA synthesis. It is used during selective isolation of gram-positive bacteria and may also be used to inhibit mycobacterial growth. PEA production was observed to be dependent on growth of mycobacteria. Further study is required to elucidate the metabolic pathways involved and assess whether this compound is produced during in vivo growth of mycobacteria.