Role of hydrosulfide ions (HS-) in methylmercury resistance in Saccharomyces cerevisiae

Saccharomyces cerevisiae showed an ultradian respiratory oscillation during aerobic continuous culture. Analysis of the off-gas revealed that hydrogen sulphide production also oscillated. Production was ®rst detected at the onset of low respiration and reached a maximum (1.5 mM) prior to minimum respiratory activity. Then H 2 S concentration fell rapidly to below 0.2 mM before the onset of high respiration. Injection of respiratory oscillation perturbation agents, such as glutathione (50 mM), NaNO 2 (50 mM) or acetaldehyde (4.5 mM), transiently increased H 2 S production above 6 mM. The synchronization properties of H 2 S were analysed to reveal that changes of oscillation period and amplitude were dependent on H 2 S concentration in culture. It is concluded that H 2 S produced during oscillation produces population synchrony by respiratory chain inhibition.

Section: Discussionmentioning

confidence: 99%

Ultradian oscillation of Saccharomyces cerevisiae during aerobic continuous culture: hydrogen sulphide mediates population synchrony

Sohn¹,

Murray²,

Kuriyama³

2000

“…To score the Met auxotrophic phenotype, use SD plates supplemented with the requirements of the strain. Note that SC met medium cannot be used unless cysteine is also omitted, as either methionine or cysteine allows growth of met15 mutants (Ono et al, 1991;Cost and Boeke, 1996). construction, all 5 overhangs created by restriction digests were blunted by filling in with the Klenow large fragment of Escherichia coli DNA polymerase, and all 3 overhangs were made blunt using the 3 to 5 exonuclease activity of T4 DNA polymerase.…”

Section: New Prs Plasmidsmentioning

confidence: 99%

Designer deletion strains derived fromSaccharomyces cerevisiae S288C: A useful set of strains and plasmids for PCR-mediated gene disruption and other applications

Brachmann

Davies

Cost

et al. 1998

3,158

1,714

A set of yeast strains based on Saccharomyces cerevisiae S288C in which commonly used selectable marker genes are deleted by design based on the yeast genome sequence has been constructed and analysed. These strains minimize or eliminate the homology to the corresponding marker genes in commonly used vectors without significantly affecting adjacent gene expression. Because the homology between commonly used auxotrophic marker gene segments and genomic sequences has been largely or completely abolished, these strains will also reduce plasmid integration events which can interfere with a wide variety of molecular genetic applications. We also report the construction of new members of the pRS400 series of vectors, containing the kanMX, ADE2 and MET15 genes. © 1998 John Wiley & Sons, Ltd.

“…Therefore we focused on two interesting candidates, the MET2 and MET15 genes, since their disruption would rationally lead to: (a) methionine requirement; and (b) accumulation of hydrosulphide ions. Accumulated hydrosulphide is known to easily form a complex with heavy metal ions and thus would modulate the colour of the colonies (due to the resulting precipitate) and would decrease susceptibility toward heavy metals (Cost and Boeke, 1996;Ono et al, 1991;Singh and Sherman, 1974). The C. guilliermondii open reading frames (ORFs) PGUG_04771 and PGUG_01379 exhibited significant identities with the C. albicans MET2 and MET15 genes, respectively.…”

Section: Resultsmentioning

confidence: 99%

Disrupting the methionine biosynthetic pathway in Candida guilliermondii: characterization of the MET2 gene as counter‐selectable marker

Montoya

Mélin

Blanc

et al. 2014

Candida guilliermondii (teleomorph Meyerozyma guilliermondii) is an ascomycetous species belonging to the fungal CTG clade. This yeast remains actively studied as a result of its moderate clinical importance and most of all for its potential uses in biotechnology. The aim of the present study was to establish a convenient transformation system for C. guilliermondii by developing both a methionine auxotroph recipient strain and a functional MET gene as selection marker. We first disrupted the MET2 and MET15 genes encoding homoserine-O-acetyltransferase and O-acetylserine O-acetylhomoserine sulphydrylase, respectively. The met2 mutant was shown to be a methionine auxotroph in contrast to met15 which was not. Interestingly, met2 and met15 mutants formed brown colonies when cultured on lead-containing medium, contrary to the wild-type strain, which develop as white colonies on this medium. The MET2 wild-type allele was successfully used to transfer a yellow fluorescent protein (YFP) gene-expressing vector into the met2 recipient strain. In addition, we showed that the loss of the MET2-containing YFPexpressing plasmid can be easily observed on lead-containing medium. The MET2 wildtype allele, flanked by two short repeated sequences, was then used to disrupt the LYS2 gene (encoding the α-aminoadipate reductase) in the C. guilliermondii met2 recipient strain. The resulting lys2 mutants displayed, as expected, auxotrophy for lysine. Unfortunately, all our attempts to pop-out the MET2 marker (following the recombination of the bordering repeat sequences) from a target lys2 locus were unsuccessful using white/brown colony colour screening. Nevertheless, this MET2 transformation/disruption system represents a new versatile genetic tool for C. guilliermondii.