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Biomedical subjects

M Yang

Publications and source records attributed to M Yang.

At least 505 records · Page 28Linked to original sources
PubMed1987

Characterization and mapping of the Bacillus subtilis prtR gene.

A gene from Bacillus natto encoding a 60-amino-acid peptide has been previously described that, when cloned on a high-copy plasmid in B. subtilis, enhances production of alkaline protease, neutral protease, and levansucrase. An identical gene was isolated from B. subtilis and caused a similar phenotype when placed on a high-copy plasmid. Genetic mapping localized this gene near metB, distant from other pleiotropic genes causing similar effects. Deletion of this gene from the B. subtilis chromosome had no obvious phenotypic effect.

Amino Acid Sequence↗
PubMed1986

Identification of the pleiotropic sacQ gene of Bacillus subtilis.

The sacQ gene of Bacillus subtilis, a pleiotropic gene affecting the expression of a number of secreted gene products, has been identified as a small 46-amino-acid polypeptide. The increased expression of this polypeptide in strains carrying the sacQ36 allele, or in strains carrying the sacQ gene on a high copy plasmid, appears to be responsible for the phenotype of higher levels of proteases seen in these strains. A deletion of the sacQ gene had no apparent phenotype, indicating that it is not an essential gene.

Alleles↗
PubMed1986

CSF brain creatine kinase levels and lactic acidosis in severe head injury.

The posttraumatic creatine kinase-BB isoenzyme (CKBB) activity and lactate concentration in ventricular cerebrospinal fluid (CSF) have been studied in 29 patients with severe head injuries. The CKBB activity reaches its maximum a few hours after trauma, and has a monoexponential drop with a half-time of approximately 10 hours. Ventricular CSF lactate concentration continues to rise in patients with a poor outcome, and decreases only slowly and inconsistently in most of the other patients. Thus, increase of lactate in the ventricular CSF is not, like CKBB, a direct one-stage consequence of the trauma but is due to continuous production from a derangement of metabolism caused by the trauma. Since even higher ventricular CSF lactate levels can be survived when not caused by head injury, and since no significant pH changes were related to the ventricular CSF lactic acidosis in these artificially ventilated patients, it is concluded that ventricular CSF lactic acidosis is indicative of a severe, although not necessarily intractable, disturbance of brain function associated with intracellular lactate production and acidosis.

Acidosis, Lactic↗
PubMed1983

Nucleotide sequence of the amylase gene from Bacillus subtilis.

The gene coding for amylase (EC.3.2.1.1) has been isolated and sequenced from Bacillus subtilis by cloning in lambda Charon4A and pBR322. The entire coding sequence and large preceding and following regions, comprising the presumed transcriptional and translational regulatory regions, were sequenced. The coding sequence shows a large open reading frame with a translated molecular weight of 72,800 and a presumed signal sequence of approximately thirty-two amino acids. When the intact gene is present in Escherichia coli, it confers the ability to degrade starch, indicating that the gene is expressed in a functional state.

Amino Acid Sequence↗
PubMed1981

Nucleotide sequence of cloned rat serum albumin messenger RNA.

The nucleotide sequences of the recombinant DNA inserts of three bacterial plasmid clones containing nearly all of the rat serum albumin mRNA have been determined. A statistical analysis of the nucleotide sequence reveals a pattern of repeated internal homology that confirms the "intragenic triplication" model of albumin evolution.

Amino Acid Sequence↗
PubMed1981

Sequence homology between RNAs encoding rat alpha-fetoprotein and rat serum albumin.

We have determined the sequences of the recombinant DNA inserts of three bacterial plasmid cDNA clones containing most of the rat alpha a-fetoprotein mRNA. The resultant nucleotide sequence of alpha-fetoprotein was exhaustively compared to the nucleotide sequence of the mRNA encoding rat serum albumin. These two mRNAs have extensive homology (50%) throughout and the same intron locations. The amino acid sequence of rat alpha-fetoprotein has been deduced from the nucleotide sequence, and its comparison to rat serum albumin's amino acid sequence reveals a 34% homology. The regularly spaced positions of the cysteines found in serum albumin are conserved in rat alpha-fetoprotein, indicating that these two proteins may have a similar secondary folding structure. These homologies indicate that alpha-fetoprotein and serum albumin were derived by duplication of a common ancestral gene and constitute a gene family.

Amino Acid Sequence↗
PubMed1981

Fine structure and evolution of the rat serum albumin gene.

The exons, their boundaries, and approximately half of the intronic deoxyribonucleic acid of the rat serum albumin gene were sequenced. In addition to the 14 exons identified earlier by R-loop analysis, a small exon was detected between the "leader" exon (Z) and exon B. The leader exon encoded the 5'-untranslated portion of albumin messenger ribonucleic acid and the "pre-pro" oligopeptide present on the nascent protein. The sites of initiation and termination of transcription were tentatively identified by comparison of the 5' and 3' gene-flanking sequences with those of other eucaryotic genes. All 28 intron/exon junctions conformed to the "GT-AG rule" (Breathnach et al., Proc. Natl. Acad. Sci. 75:4853-4857, 1978). The three homologous domains of albumin were encoded by three subgenes that consisted of four exons each and evolved by intragenic duplication of a common ancestor. The second and forth exons of each subgene appeared to be the result of an even earlier duplication event. We propose a model for the evolution of this gene that accounts for the observed patterns of exon size and homology.

Animals↗
PubMed1980

Hypotensive action of parathyroid hormone preparations on rats and dogs.

Bovine parathyroid extract and two commercial preparations containing the first 34 amino acids of synthetic bovine parathyroid hormone [bPTH-(1-34)]produced dose-related hypotension in anesthetized rats. Dogs were 10 times more sensitive to the two bPTH-(1-34) preparations than were rats. Propranolol, phentolamine, atropine, and promethazine did not affect the hypotensive action of bPTH-(1-34) in rats and dogs. bPTH-(1-34) decreased perfusion pressure in rat hindlimbs perfused in situ with Ringer's solution and was a vasodilator in dog kidneys perfused in vitro with Ringer's solution. Helical strips of rabbit aorta were also relaxed by bPTH-(1-34). We conclude that the direct vasodilatory action of bPTH preparations represents an intrinsic property of parathyroid hormone and that the hypotensive effect of this hormone is produced by part or all of the first NH2-terminal 34 amino acids.

Adrenergic alpha-Antagonists↗
PubMed1979

Automated measurement of alpha, beta, sigma, and theta burst characteristics.

An automatic system was used for the selection and analysis of alpha, beta, and theta waveforms occurring in the awake and REM sleep states and sleep spindles occurring in stage 2 sleep. Two nights of sleep were analyzed for each of five normal subjects in each of five age groups: 3--5; 13; 25--34; 43--53; and 67--79 years of age. The waveform frequencies, length, and rate of occurrence were measured. No age-related changes were found in the alpha frequency (except for the younger group). No significant age differences were found in the beta and theta frequencies in the awake state. During REM sleep, the average beta and theta frequencies of the two youngest groups were significantly different from those of the three older groups. The average frequency of stage 2 sleep spindles of the two youngest groups was less than that in the middle group; the average spindle frequency of this group was significantly less than that of the two older groups. The number of spindles per minute was significantly less for the younger group and significantly more for the 25- to 34-year-olds.

Adolescent↗
PubMed1977

Ontogeny of delta activity during human sleep.

The study describes the ontogenetic and time-related changes in peak amplitude, frequency, and incidence of delta waves of twenty-five normal subjects between the ages of 3 and 79 years of age. All slow waves greater then 5 muV in magnitude and between 0.5 and 3.0 c/sec were analyzed for the first 6 h of the night's sleep. In this study increasing age was accompanied by decreases in average peak amplitude of delta waves over 5 muV, slowing of delta frequencies, and decreases in incidence of waves greater than 20 muV. Across 2-h epochs of the night there were tendencies for the average peak amplitude of delta waves to decrease, for the average frequency for a given amplitude range to decrease, and for the incidence of low-amplitude delta waves to increase and high-amplitude waves to decrease. The incidence of waves greater than 5 muV remained constant across ages and epochs. Frontal channel delta waves exhibited an age-group difference whereas no such difference was apparent for central channel delta activity, suggesting that the frontal channel may possess advantages over the central because of greater sensitivity to age related changes.

Adolescent↗
PubMed1977

Ecotaxis: the principle and its application to the study of Hodgkin's disease.

A study of the function, characterization and distribution of T and B lymphocytes in five children with Hodgkin's disease is presented. The results, indicating that lymphocyte depletion in the peripheral blood does not necessarily reflect an overall lack of circulating lymphocytes, are presented to demonstrate that failure of ecotaxis (normal lymphocyte migration and distribution) can occur in man. The underlying reasons for such failure and their relevance to the pathogenesis of Hodgkin's disease are discussed.

Adolescent↗