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Biomedical subjects

H Murphy

Publications and source records attributed to H Murphy.

13 recordsLinked to original sources

The nucleotide sequence of recG, the distal spo operon gene in Escherichia coli K-12.

A gene is identified in the Escherichia coli K-12 spo operon as recG. Previously identified genes in the spo operon were spoS, alias rpoZ, encoding the omega (omega) subunit of RNA polymerase, as well as the spoT gene encoding the major cellular source of guanosine 3',5'-bispyrophosphate hydrolase activity. The gene order within the spo operon is: spoS (rpoZ), spoT, spoU, recG. A convergent gltS gene is present beyond the spo operon. Mutants bearing recG deletion-insertion alleles display mild sensitivities to both ultraviolet irradiation and to mitomycin C, which is expected to be due to a known recG insertion allele. Deletion-insertion mutations in upstream operon genes (spoT and spoU) show polar effects on these assays of recG function. The deduced 693-amino acid (aa) RecG sequence shows a weak, but significant, relatedness to aa sequence motifs previously reported for putative helicases involved in replication, recombination, and DNA repair.

Amino Acid Sequence

Effects of in-utero exposure to oral hypoglycaemic drugs.

The observation that several Mexican-American women were taking oral hypoglycaemic agents while pregnant led to a study to confirm reports of associations between these agents and congenital abnormalities. 20 non-insulin-dependent (NIDDM) pregnant diabetic women with exposure to oral hypoglycaemic drugs during embryogenesis and 40 pregnant NIDDM women matched for age, race, parity, weight, and glycaemic control but not exposed to oral hypoglycaemic drugs were followed up. 10 infants (50%) in the exposed group had congenital malformations, compared with only 6 (15%) in the control group (p less than 0.002). 5 (25%) infants in the exposed group had ear malformations, anomalies not commonly described in diabetic embryopathy. Hyperbilirubinemia (p less than 0.04), polycythaemia, and hyperviscosity requiring partial exchange transfusions (p less than 0.03) were commoner among babies in the exposed than in the control group. 3 babies in the exposed group but none in the comparison group had severe prolonged neonatal hypoglycaemia lasting 2, 4, and 7 days; 2 of the 3 had been exposed for 22 and 28 weeks during gestation, whereas the third had been exposed throughout the first trimester. Although exposure to oral hypoglycaemic drugs during fetal life seems to be associated with congenital malformations and neonatal hypoglycaemia, a large, prospective study is needed to exclude the confounding effect of maternal metabolic derangement secondary to diabetes.

Abnormalities, Drug-Induced

rhlB, a new Escherichia coli K-12 gene with an RNA helicase-like protein sequence motif, one of at least five such possible genes in a prokaryote.

A newly recognized gene we name rhlB, after RNA helicase-like genes, has been found in the 85-minute region of the Escherichia coli chromosome. This gene encodes protein sequence motifs similar to those known for "D-E-A-D box" gene products. Proteins in this gene family occur in eukaryotes as well as prokaryotes, and, as far as tested, have been found to participate in ATP-dependent RNA helicase or RNA-dependent ATPase activities. The functions of these enzymes are poorly understood. In yeast, mutant phenotypes of various D-E-A-D genes suggest that they function in RNA splicing, processing, or translation. We find that rhlB is necessary for viability only in some genetic backgrounds. Conditional rhlB lethality is not complemented by another E. coli RNA helicase-like gene (srmB). Using primers with homology to consensus sequences in D-E-A-D box proteins, we have recovered DNA fragments amplified from E. coli genomic DNA by polymerase chain reactions. Sequence analysis of these fragments suggests that E. coli possesses at least five RNA helicase-like (rhl) D-E-A-D box genes at widely separated chromosomal locations. The multiplicity of such genes in a prokaryote raises the possibility of important roles for the corresponding class of biologically widespread proteins.

Amino Acid Sequence

Factor M as a correlate of physical fitness: imagination or just more energy.

Determined whether 16PF scale scores could contribute significantly to the prediction of a measure of fitness. Sixty-three firemen from a large metropolitan area in the Southeast were Ss. Factor M contributed significantly to the prediction of one measure of fitness (i.e., treadmill time). The assumption cited in the literature that Factor M reflects "imagination" in individuals who score high on fitness measures was questioned. The article concluded that Cattell's earlier work relating high Factor M to high energy and endurance suggests a more logical interpretation of Factor M vis à vis measures of fitness.

Adult

Double blind trial of ritodrine and placebo in twin pregnancy.

In a double blind trial, 25 patients with twin pregnancy were given 40 mg of ritodrine hydrochloride by mouth daily and 24 similar patients received a placebo. The ritodrine group had no significant prolongation of pregnancy nor increase in birth weight, and a high incidence of side effects occurred.

Clinical Trials as Topic

Plaque assay of avian sarcoma viruses using casein.

The caseinolytic activity of several strains of Rous sarcoma virus (RSV), conditional and nonconditional mutants of RSV, and nontransforming avian leukosis viruses was investigated. Only those viruses capable of transforming chick fibroblasts in vitro induced lysis of casein incorporated into an agar overlay. Lysis produced distinct clear areas in the turbid casein-agar gel which allowed a quantitative "plaque" assay of cell transformation. Casein plaque formation could not be separated from morphological conversion in cultures infected by wild-type RSV strains. In plates infected by mutants temperature sensitive for transformation, the caseinolytic activity appeared to be affected by temperature to a lesser extent than morphological conversion.

Avian Leukosis Virus