Biomedical subjects

S Swift

Publications and source records attributed to S Swift.

75 records · Page 5Linked to original sources

PubMedDate not supplied

The role of RsmA in the regulation of swarming motility in Serratia marcescens.

Swarming motility is a multicellular phenomenon comprising population migration across surfaces by specially differentiated cells. In Serratia marcescens, a network exists in which the flhDC flagellar regulatory master operon, temperature, nutrient status, and quorum sensing all contribute to the regulation of swarming motility. In this study, the rsmA (repressor of secondary metabolites) gene (hereafter rsmA(Sm)) was cloned from S. marcescens. The presence of multicopy, plasmid-encoded rsmA(Sm) expressed from its native promoter in S. marcescens inhibits swarming. Synthesis of N-acylhomoserine lactones, presumably by the product of smaI (a luxI homolog isolated from S. marcescens), was also inhibited. Knockout of rsmA(Sm) on the S. marcescens chromosome shortens the time before swarming motility begins after inoculation to an agar surface. A single copy of the chromosomal PrsmA(Sm)::luxAB reporter of rsmA(Sm) transcription was constructed. Using this reporter, the roles of the flhDC flagellar regulatory master operon, temperature and autoregulation in the control of rsmA(Sm) expression were determined. Our findings indicate that RsmA(Sm) is a component of the complex regulatory network that controls swarming.

Amino Acid Sequence↗

PubMedDate not supplied

Identification of the breast cancer susceptibility gene BRCA2.

In Western Europe and the United States approximately 1 in 12 women develop breast cancer. A small proportion of breast cancer cases, in particular those arising at a young age, are attributable to a highly penetrant, autosomal dominant predisposition to the disease. The breast cancer susceptibility gene, BRCA2, was recently localized to chromosome 13q12-q13. Here we report the identification of a gene in which we have detected six different germline mutations in breast cancer families that are likely to be due to BRCA2. Each mutation causes serious disruption to the open reading frame of the transcriptional unit. The results indicate that this is the BRCA2 gene.

Amino Acid Sequence↗

PubMedDate not supplied

Simultaneous measurement of hundreds of liver proteins: application in assessment of liver function.

Proteins implement most biological functions at the molecular level. As one might expect based on this fact, it appears that the altered functional states associated with toxic effects involve changes in the abundance or structure of proteins. Although numerous specific assays exist to measure changes in the abundance of individual proteins, practical limitations have prevented widespread use of multiple protein assays for the global characterization of toxicity. Recent developments in protein analytical technology are rapidly changing this picture. Two-dimensional gel electrophoresis, a technique capable of resolving and quantitating hundreds of proteins simultaneously, is becoming an automated, high-throughput tool. In parallel, techniques have been developed that allow the resulting deluge of protein measurements to be organized into a prototype Molecular Effects Database describing xenobiotic effects in rodent liver. This database can detect, classify, and characterize a broad range of liver toxicity mechanisms. It currently contains approximately 10 million protein measurements, including data on the liver effects of 43 compounds, with a further 50 compounds to be added in 1995. Observed effects range from very broad (sex steroids alter levels of 45% of all liver proteins) to very specific (e.g., hepatic hydroxymethyl glutaryl coenzyme A reductase inhibitors). Companion 2-dimensional databases describing rodent brain and kidney have been initiated, as have linkages to the genomic sequence databases. Assimilation of this approach into research and regulatory toxicology poses an interesting challenge--one that is likely to lead to a radically more sophisticated understanding of toxicity and its biological basis.

Animals↗