Glutathione (gamma-l-glutamyl-l-cysteinylglycine) is an important antioxidant molecule, helping t... more Glutathione (gamma-l-glutamyl-l-cysteinylglycine) is an important antioxidant molecule, helping to buffer the cell against free radicals and toxic electrophiles. Expression of the yeast GSH1 gene, encoding the first enzyme involved in glutathione biosynthesis, gamma-glutamylcysteine synthetase, is regulated by oxidants and the heavy metal cadmium at the level of transcription. We present evidence that the transcription factors involved in controlling the network of sulfur amino acid metabolism genes are also responsible for regulating GSH1 expression in response to cadmium. In particular the transcription factors Met-4, Met-31, and Met-32 are essential for cadmium-mediated regulation of gene expression, whereas the DNA-binding protein Cbf1 appears to play a negative role in controlling GSH1 expression.
The uptake of peptides by Salmonella typhimurium is mediated by three apparently independent tran... more The uptake of peptides by Salmonella typhimurium is mediated by three apparently independent transport systems. One of these systems, the oligopeptide permease, is encoded by a genetic locus (opp) which has been mapped at 34 min on the S. typhimurium chromosomal map. We accurately mapped the location of opp by cotransduction frequencies and by deletion analysis and show that the gene order for this region of the chromosome is cysB-trp-tonB-opp-galU-tdk. All opp mutants, independently isolated by a variety of means, mapped at this one locus, between tonB and galU. Spontaneous and transposon Tn10-generated deletions were used to construct a fine-structure genetic map of opp. Evidence is presented which indicates that opp covers a 5- to 6-kb segment of DNA and is therefore likely to consist of more than one gene.
Lepeophtheirus salmonis is a copepod ectoparasite of wild and farmed salmonids and can cause cons... more Lepeophtheirus salmonis is a copepod ectoparasite of wild and farmed salmonids and can cause considerable damage to infected Wsh. We have examined the eVect of the organophosphate trichlorphon, which was one of the early treatments for sea lice as NeguvonĀ® on L. salmonis. Suppression subtractive hybridisation was used to prepare a cDNA library enriched for cDNAs expressed in response to the organophosphate trichlorophon and using this technique a total of 33 cDNAs were found to be diVerentially regulated in response to organophosphate exposure. Sequence analysis of the cDNAs revealed that many were involved in cellular stress responses and or neuro- toxicity. The expression of two of these cDNAs was conWrmed to be up-regulated in response to trichlorophon.
Glutathione (gamma-l-glutamyl-l-cysteinylglycine) is an important antioxidant molecule, helping t... more Glutathione (gamma-l-glutamyl-l-cysteinylglycine) is an important antioxidant molecule, helping to buffer the cell against free radicals and toxic electrophiles. Expression of the yeast GSH1 gene, encoding the first enzyme involved in glutathione biosynthesis, gamma-glutamylcysteine synthetase, is regulated by oxidants and the heavy metal cadmium at the level of transcription. We present evidence that the transcription factors involved in controlling the network of sulfur amino acid metabolism genes are also responsible for regulating GSH1 expression in response to cadmium. In particular the transcription factors Met-4, Met-31, and Met-32 are essential for cadmium-mediated regulation of gene expression, whereas the DNA-binding protein Cbf1 appears to play a negative role in controlling GSH1 expression.
The uptake of peptides by Salmonella typhimurium is mediated by three apparently independent tran... more The uptake of peptides by Salmonella typhimurium is mediated by three apparently independent transport systems. One of these systems, the oligopeptide permease, is encoded by a genetic locus (opp) which has been mapped at 34 min on the S. typhimurium chromosomal map. We accurately mapped the location of opp by cotransduction frequencies and by deletion analysis and show that the gene order for this region of the chromosome is cysB-trp-tonB-opp-galU-tdk. All opp mutants, independently isolated by a variety of means, mapped at this one locus, between tonB and galU. Spontaneous and transposon Tn10-generated deletions were used to construct a fine-structure genetic map of opp. Evidence is presented which indicates that opp covers a 5- to 6-kb segment of DNA and is therefore likely to consist of more than one gene.
Lepeophtheirus salmonis is a copepod ectoparasite of wild and farmed salmonids and can cause cons... more Lepeophtheirus salmonis is a copepod ectoparasite of wild and farmed salmonids and can cause considerable damage to infected Wsh. We have examined the eVect of the organophosphate trichlorphon, which was one of the early treatments for sea lice as NeguvonĀ® on L. salmonis. Suppression subtractive hybridisation was used to prepare a cDNA library enriched for cDNAs expressed in response to the organophosphate trichlorophon and using this technique a total of 33 cDNAs were found to be diVerentially regulated in response to organophosphate exposure. Sequence analysis of the cDNAs revealed that many were involved in cellular stress responses and or neuro- toxicity. The expression of two of these cDNAs was conWrmed to be up-regulated in response to trichlorophon.
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