Detection of small genotypic changes in Escherichia coli by pyrolysis mass spectroscopy

Abstract Pyrolysis mass spectrometry (Py-MS0 has been used to discriminate between four very closely related strains of Escherichia coli ; a parent strain UB5021 and three derivatives each containing one of the antibiotic resistance plasmids, pBR322, pACYC184 or R388.     

Hepatoprotection by L-cysteine-glutathione mixed disulfide,a sulfhydryl-modified prodrug of glutathione

L-Cysteine-glutathione disulfide, a ubiquitous substance present in mammalian cells, was shown to be highly effective in protecting mice against acetaminophen-induced hepatotoxicity. Since the corresponding D-cysteine-glutathione disulfide was totally ineffective in this regard, an enzymatic mechanism that provides glutathione directly to cells is postulated.     

Reproducibility of pyrolysis mass spectrometry: effect of growth medium and instrument stability on the differentiation of selected Bacillus species

The discrimination of a set of 53 strains, taken from four closely related Bacillus species ( Bacillus subtilis, B. pumilus, B. licheniformis and B. amyloliquefaciens ), was examined using pyrolysis mass spectrometry. Strains were grown on six different media to examine the effect of media variation, especially batch-to-batch variation of a single medium, on the pyrolysis mass spectra and strain discrimination achieved. Long-term reproducibility over a period of 14 months was also examined. It was shown that batch-to-batch media variation is insufficient to affect spectra and strain discrimination significantly, but different media types do affect this. It was shown that species groups could still be recovered from the data, however, with an appropriate data-handling system. It was not possible to directly compare spectra produced 14 months apart, but the strain and species discrimination achieved using each data-set were highly comparable.