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Biomedical subjects

J Beckwith

Publications and source records attributed to J Beckwith.

188 records · Page 11Linked to original sources
PubMedDate not supplied

Alkaline phosphatase fusions in the study of cell division genes.

Alkaline phosphatase fusions have been used to analyse plasmid- or phage-carried genes from the two-minute region of the Escherichia coli chromosome. These studies have revealed the following: 1) Bacteriophage lambda carries two genes for cell envelope proteins, lom and bor, that are expressed in lysogens and probably contribute to the pathogenicity of its E. coli host. 2) The ftsQ and ftsl gene products are integral proteins of the cytoplasmic membrane with small cytoplasmic domains and large periplasmic domains. 3) The ftsQ and ftsl gene products are made in very small amounts, on the order of 25 molecules per cell. 4) The ftsQ gene product is essential for cell growth and is required throughout the formation of the cell septum. 5) An open reading frame just upstream from ftsl, thought to be involved in cell division, is expressed and probably codes for a cytoplasmic membrane protein.

Alkaline Phosphatase↗
PubMedDate not supplied

Signal sequence mutations disrupt feedback between secretion of an exported protein and its synthesis in E. coli.

Recent studies in a eukaryotic system indicate that a block in secretion can lead to a block in the translation of secretory proteins. This feedback on protein synthesis is thought to be a result of an interaction of the signal recognition particle with the signal sequences of nascent proteins. Genetic studies in the prokaryote Escherichia coli suggest that a complex secretion machinery and a similar feedback mechanism exist. In addition, mutations affecting two genes, secA and secC, thought to encode components of the bacterial secretion machinery, selectively interfere with the synthesis of exported proteins. This selective interference with translation may be a result of recognition by the secretion machinery of signal sequences. If so, alteration of the signal sequence of a particular protein by mutation should eliminate the block in synthesis for that protein. We show here that signal sequence mutants for an exported protein, maltose binding protein, prevent the block in synthesis of this protein in a secA mutant.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

Mutations that alter the DNA sequence specificity of the catabolite gene activator protein of E. coli.

Three mutations that alter the DNA sequence specificity of the catabolite gene activator protein (CAP) from AA-TGTGA--T---TCA-ATW to AA-TGTAA--T---TCA-ATW have been isolated. All three mutations affect the same amino acid of CAP, glutamic acid 181. We propose that it is this amino acid of CAP that makes contacts with base pairs 7 and 16 of the symmetrical recognition site.

Amino Acid Sequence↗
PubMedDate not supplied

Genetic fatalism and social policy: the implications of behavior genetics research.

Recent advances in molecular genetics methods have provided new means of determining the genetic bases of human behavioral traits. The impetus for the use of these approaches for specific behaviors depends, in large part, on previous familial studies on inheritance of such traits. In the past, a finding of a genetic basis for a trait was often accompanied with the idea that that trait is unchangeable. We discuss the definition of "genetic trait" and heritability and examine the relationship between these concepts and the malleability of traits for both molecular and nonmolecular approaches to behavioral genetics. We argue that the malleability of traits is as much a social and political question as it is a biological one and that whether or not a trait is genetic has little relevance to questions concerning determinism, free will, and individual responsibility for actions. We conclude by noting that "scientific objectivity" should not be used to conceal the social perspectives that underlie proposals regarding social change.

Female↗