Search PubMed⌕ Search

Biomedical subjects

J A Winter

Publications and source records attributed to J A Winter.

33 records · Page 2Linked to original sources
PubMed1988

Structure, expression, and evolution of the 5-enolpyruvylshikimate-3-phosphate synthase genes of petunia and tomato.

5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase is an enzyme of the shikimate pathway which is located in the chloroplasts in higher plants. This enzyme is the target of the nonselective herbicide glyphosate. We have isolated and sequenced cDNA clones encoding EPSP synthase from petunia and tomato. The deduced amino acid sequences of the two enzyme precursors show 93% identity in the mature protein regions and 58% identity in the transit peptides. The sequences of the plant enzymes show significantly greater similarity to bacterial EPSP synthases than to fungal EPSP synthases. A genomic clone containing an EPSP synthase gene was isolated from a library of petunia DNA and was shown to contain seven intervening sequences. This gene is expressed approximately 25-fold higher in flower petals than in other organs of petunia. Transcription of this gene is initiated at multiple sites in petunia leaves and in a glyphosate-tolerant petunia cell line overproducing EPSP synthase mRNA. In petals, however, transcription of this gene is initiated almost entirely from only one of these sites. In contrast to petunia, the levels of EPSP synthase mRNA in different organs of tomato do not differ significantly.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1987

Comparison of cauliflower mosaic virus 35S and nopaline synthase promoters in transgenic plants.

We have compared the level of expression of the Cauliflower Mosaic Virus 35S promoter and the nopaline synthase promoter when fused to a common reporter gene. A cassette containing the neomycin phosphotransferase (type II) coding sequence followed by the nopaline synthase 3' nontranslated region was used for transcriptional and translational evaluation of the two different promoters. These chimeric genes were introduced into petunia plants and the copy number of the gene, the steady state level of NPTII transcript and the levels of NPTII enzyme activity were determined. In this paper, we report that the NPT II transcript levels are on the average 30 fold higher in plants containing CaMV 35S promoter and leader sequences than in plants containing the same reporter gene but nopaline synthase promoter and leader sequences. Similarly, plants containing the CaMV 35S promoter had an average of 110 fold higher levels of NPTII enzyme activity than those containing the nopaline synthase promoter. The significance of these results for expression of foreign genes in plants is discussed. In addition, we describe the construction of a convenient plant expression cassette vector (pMON316) which utilizes the CaMV 35S promoter.

Amino Acid Oxidoreductases↗
PubMed1984

Map locations of five transcripts homologous to TR-DNA in tobacco and sunflower crown gall tumors.

Polyadenylated RNA from two octopine type tumor lines (E1, PSCG-15955) was analyzed by RNA blot hybridization and shown to contain five major transcripts homologous to TR DNA. In tobacco E1 tissue, the molecular weights of the TR homologous RNAs are 1.65 kb, 1.55 kb, 1.45 kb, 1.05 kb, and 0.78 kb. The 5' - and 3'-termini of each of the five E1 tumor transcripts were determined by S1 nuclease hybrid protection mapping. The polarity of transcription for the 0.78, 1.05 and 1.65 kb RNAs is from left to right, while the 1.55 and 1.45 kb RNAs are transcribed from right to left. Although we see the same size transcripts in sunflower PSCG-15955 tissue (with the exception of a 0.89 kb RNA in place of the 1.55 kb transcript of E1) there is an apparent difference in the relative abundance of the various RNAs between the two tumor lines.

Base Sequence↗
PubMed1983

Concentration of 18:1 and 16:1 transunsaturated fatty acids in the adipose body tissue of decedents dying of ischaemic heart disease compared with controls: analysis by gas liquid chromatography.

Proportions of "lower" 16:1 and 18:1 trans acids (TL) and "higher" C20 and C22 trans acids (TH) in samples of depot fat taken at postmortem examination from 136 people who had died of ischaemic heart disease (cases) and from those who had died of unrelated causes (controls) have been determined. Whereas mean percentages of TH are virtually identical for cases and controls, the mean value of TL was significantly higher for the case specimens. Although these lower trans acids are present in small amounts in ruminant-animal fat, they are more characteristic of commercially hydrogenated fats. We conclude, therefore, that the cases consumed on average a higher proportion of those hydrogenated fats rich in 16:1 trans and 18:1 trans acids and a lower proportion of ruminant fat than did the controls.

Adipose Tissue↗
PubMed1983

Concentration of transunsaturated fatty acids in the adipose body tissue of decedents dying of ischaemic heart disease compared with controls.

The constituents of the fat of 136 decedents who had died of ischaemic heart disease are compared with the constituents of the fat from 95 controls who had died from other causes. The cases had a lower concentration of fatty acids (L) characteristic of ruminant animal fat and a higher concentration of total transunsaturated acids (T), but the concentrations of certain higher (C20 and C22 mostly monoenoic) acids (H) were similar. The ratio T/L was higher in the cases, which suggests that the cases may have consumed more hydrogenated fats in life than had the controls. The ratio T/L increased linearly with H within both the case and control specimens, which suggests in view of the similarity in the mean levels of H that the difference in trans contents may be concentrated in the lower (18:1 and 16:1) trans acids.

Adipose Tissue↗
PubMed1981

Hydrogenated oils and fats: the presence of chemically-modified fatty acids in human adipose tissue.

A total of 231 samples of adipose tissue has been analyzed for trans unsaturated acids which arise in large measure via consumption of hydrogenated fat; 136 specimens derived from patients who had died of ischemic heart disease (cases), the remainder being controls. They have also been analyzed by gas-liquid chromatography which gave information regarding the amounts of 1) "higher acids"--C20 plus C22 acids, mainly monoenoic--which derive from hydrogenated marine oils present in high amounts in certain margarines in the United Kingdom, and 2) "lower acids"--14:1 plus odd-numbered and branched chain acids in the C15 to C17 range--which are present in hydrogenated fat in lower amounts than in, say, butter-fat. Values of trans unsaturated acids tend to be higher, and values of lower acids lower for cases than controls, but we cannot at present conclude that these differences are statistically significant. Case versus control levels in respect of higher acids and linoleic acid do not appear to be significantly different.

Adipose Tissue↗
PubMedDate not supplied

Differential effects of betamethasone and dexamethasone fetal administration of parturition in sheep.

OBJECTIVE: We tested the hypothesis that betamethasone is more potent than dexamethasone in inducing the essential mechanisms of parturition in sheep. METHODS: Twenty-one sheep were instrumented under general anesthesia with maternal and fetal arterial and venous catheters and myometrial electromyogram electrodes at 117 days' gestation (dGA). At 125 dGA at 12:00 PM, after 2 days of baseline recording, either saline (n = 7, control group), betamethasone (n = 7), or dexamethasone (n = 7) was administered into the fetal jugular vein at a rate of 10 micrograms/hour. A total dose of 0.48 mg was given over the next 48 hours. The animals underwent autopsy 3 days after the end of the infusion period (130 dGA), or earlier if labor resulted from the glucocorticoid administration. Daily maternal and fetal arterial blood samples (4 mL) for hormone measurement were taken at 10:00 AM throughout the study period. Additional arterial blood samples were taken if the animal developed labor. Maternal plasma progesterone and fetal ACTH and cortisol concentrations were measured by radioimmunoassay, and corticosteroid-binding globulin (CBG) binding capacity was determined by saturation analysis. Myometrial activity was monitored continuously throughout the experimental protocol. RESULTS: All seven betamethasone-treated animals developed labor after the glucocorticoid infusion regimen. In contrast, only two of seven dexamethasone-treated animals developed labor. Fetal treatment with betamethasone produced a greater and earlier fall in maternal plasma progesterone than fetal treatment with dexamethasone. Both betamethasone and dexamethasone treatments elevated fetal plasma CBG to similar binding capacities. Elevated fetal plasma ACTH and cortisol concentrations at the end of the infusion period in both betamethasone-and dexamethasone-treated animals were not related to the development of labor-type contractions. CONCLUSION: These data support the hypothesis that betamethasone is more potent than dexamethasone in inducing the essential mechanisms of parturition in sheep.

Adrenocorticotropic Hormone↗