Jun Dai — Page 3 | PubMed Health

PubMed2002

[Study on the production of trehalose by bacterium D-97 endocellular enzymes using HPLC/RI and HPLC/ESI-MS].

The mechanism in which trehalose is produced from dextrin or starch hydrolyzate by endocellular enzymes of bacterium D-97 can be elucidated high performance liquid chromatography (HPLC) with differential refraction detection (RI) basically, including the effect of the different carbon sources on the endocellular trehalose-producing enzymes in bacterium D-97 and the possibility or ability of the endocellular enzymes to produce trehalose using maltooligosaccharides of different chain lengths. After purification of endocellular enzymes of bacterium D-97, two enzymes (called Enzyme A and Enzyme B) related to trehalose synthesis were found. The unknown oligosaccharides produced by Enzyme A were analyzed with the HPLC/RI and HPLC/ESI-MS (electrospray ionization mass spectrometry). The results showed the relative molecular masses of the unknown oligosaccharides were the same as those of the enzymatic reaction substances (maltotriose, maltotetraose and maltopentaose) respectively. In combining with other results of biological experiments, these unknown oligosaccharides had been identified basically. There was no reduction power in these unknown oligosaccharides and only one trehalose residue exited in the molecular chain of these unknown oligosaccharides.

Bacteria↗

PubMedDate not supplied

Garlic and its active metabolite allicin produce endothelium- and nitric oxide-dependent relaxation in rat pulmonary arteries.

1. The aims of the present study were to investigate the effects of fresh garlic and one of its active metabolites, allicin, on rat isolated pulmonary arteries (RPA). 2. In endothelium-intact and phenylephrine-precontracted RPA, the addition of a water or a 5% ethanol extract of fresh garlic (1-500 microg/mL) resulted in a dose-dependent relaxation reaching a maximum (mean +/- SEM) of -91 +/- 3 and -93 +/- 2%, respectively, with an ED(50) of 113 +/- 12 and 106 +/- 10 microg/mL, respectively. The vasorelaxation was readily reversible upon washing and no tachyphylaxis was noted. 3. An extract of the external garlic storage leaf produced a significantly greater relaxation than the inner stem. Microfiltration of extracts with a 10,000 molecular sieve did not attenuate relaxation. Inactivation of alliinase and allicin formation, with either boiling of the garlic clove for 30 min or 100% ethanol treatment, completely abolished relaxation. In contrast, similar treatment of crushed garlic with formed allicin retained the relaxation response. 4. Pure allicin produced a similar relaxation as garlic extract, with an EC(50) of approximately 0.8 microg/mL. Disruption of endothelium or N(G)-nitro-L-arginine methyl ester pretreatment attenuated the relaxation, whereas indomethacin had no effect. 5. Prior garlic (500 microg/mL) treatment enhanced acetylcholine relaxation by shifting the response curve to the left, but had no effect on nitric oxide (NO) donor-induced responses. 6. These results demonstrate that garlic and the active metabolite allicin are capable of eliciting a NO-dependent relaxation in RPA and that this response is likely to be mediated via garlic activation of NO formation rather than its stabilization.

Animals↗