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S McCormick

Publications and source records attributed to S McCormick.

At least 37 records · Page 2Linked to original sources
PubMed1991

Ac transposition from a T-DNA can generate linked and unlinked clusters of insertions in the tomato genome.

We have investigated the distribution of transposed Acs in the tomato genome. Our approach has been to clone the regions flanking the T-DNAs and transposed Acs from two transgenic lines of tomato and place these sequences on the tomato restriction fragment length polymorphism (RFLP) map. The distribution of transposed Acs around the T-DNA and at locations unlinked to the T-DNA indicates that Ac transposes to linked and unlinked sites in tomato as it does in maize. The structure and terminal sequence of these cloned elements shows that Ac remains intact after transposition. We discuss these results and their bearing on gene tagging strategies using Ac and Ds.

Base Sequence↗
PubMed1991

Promoter analysis of genes that are coordinately expressed during pollen development reveals pollen-specific enhancer sequences and shared regulatory elements.

We have investigated the functional organization and properties of cis regulatory elements in the promoter regions of two genes from tomato (LAT52 and LAT59) that are preferentially and coordinately expressed during pollen maturation. Promoter deletion analysis in transgenic plants demonstrated that only minimal (less than 200 bp) promoter proximal regions are required for developmentally regulated expression in pollen and in specific cell types of the sporophyte. Cis-acting regulatory regions of these two promoters and of a third pollen-expressed promoter (LAT56) were characterized in detail using a transient expression assay. We identified two upstream activator regions in the LAT52 promoter and further showed that a 19-bp segment from one of those regions enhanced expression of the heterologous CaMV35S promoter in pollen. Similarities in sequence between crucial cis elements provide evidence that shared regulatory elements are involved in the coordinate expression of the LAT genes during microsporogenesis.

Base Sequence↗
PubMed1991

Molecular analysis of gene regulation and function during male gametophyte development.

We have characterised three pollen-expressed genes (LAT52, LAT56 and LAT59) from tomato in order to determine their role in pollen development, and to determine the DNA sequences responsible for gene expression in pollen. LAT52 encodes a protein that shows amino acid sequence similarity to a protein encoded by a pollen-specific cDNA clone (pZmc13) isolated from maize, and both proteins have amino acid sequence similarity to Kunitz trypsin inhibitors of soybean and winged bean. The proteins encoded by LAT56 and LAT59 genes are 54% identical at the amino acid level, and show significant sequence similarity to bacterial pectate lyases and to a fungal pectin lyase. Additionally, regions of LAT56 and LAT59 show significant sequence similarity to tryptic peptides of ragweed and Japanese cedar pollen allergens. Preliminary results suggest that plants harboring antisense constructs of the LAT52 coding region show defects in pollen germination and fertilisation; no obvious phenotype was seen in plants harboring antisense constructs of the LAT59 coding region. Promoter fragments of these three LAT genes were fused to the reporter gene GUS and assayed using both a transient system and stably transformed plants. We have identified relatively short regions of the LAT promoters that are important for pollen expression, and are attempting to isolate trans-acting factors that interact with these cis-acting sequences, using both molecular and classical genetic approaches.

Amino Acid Sequence↗
PubMed1991

A 25-year experience with 519 anterior colporrhaphy procedures.

A 25-year experience with 519 anterior colporrhaphies was reviewed to assess the results in treating genuine and mixed stress urinary incontinence, the incidence of new urinary incontinence following prolapse surgery, the incidence of new detrusor instability after incontinence and prolapse surgery, and the morbidity associated with anterior colporrhaphy. The cure rate in treating genuine stress incontinence in 194 patients was increased from 75 to 94% when a Kelly-Kennedy-type technique was modified to include a vaginal retropubic urethropexy. The surgical cure in treating mixed incontinence was unsatisfactory (64%) in unselected cases but good (84%) in selected cases. Previous incontinence surgery, especially more than one procedure, significantly reduced the cure rate for genuine stress incontinence. The incidence of new incontinence after prolapse surgery in one subgroup of patients was 11%, indicating the need for measures to minimize this possibility at prolapse surgery. The incidence of new detrusor instability after surgery was 6% (higher after incontinence surgery than after prolapse surgery). The incidence of significant morbidity, excluding incontinence, was minimal (1%) among the 519 anterior colporrhaphies.

Adult↗
PubMed1991

An open trial of buspirone added to neuroleptics in schizophrenic patients.

Twenty chronic schizophrenic patients completed at least 2 weeks of a 6-week trial of buspirone (mean dose 23.8 mg/day) added to a stable dose of neuroleptic. At week 6, mean scores were significantly improved (p less than 0.01) on the Brief Psychiatric Rating Scale, the Simpson Angus Scale for Extrapyramidal Symptoms and the Global Assessment Scale. Overall measures of akathisia and tardive dyskinesia were not significantly changed at week 6. In the 7 patients taking oral haloperidol, mean plasma concentrations of haloperidol were significantly increased (p less than 0.05) by 26% 6 weeks after adding buspirone.

Adult↗
PubMed1990

Molecular and genetic characterization of two pollen-expressed genes that have sequence similarity to pectate lyases of the plant pathogen Erwinia.

A set of cDNAs that are expressed in tomato anthers were isolated. We further characterized two of these cDNAs (LAT56 and LAT59) and their corresponding genomic clones. LAT56 and LAT59 show low levels of steady-state mRNA in immature anthers and maximal levels in mature anthers and pollen. The LAT56 and LAT59 genes are single-copy in the tomato genome, and are linked on chromosome 3, approximately 5 cM apart. Although these cDNAs did not cross-hybridize, their deduced protein sequences (P56 and P59) have 54% amino acid identity. The LAT56 and LAT59 genes each have two introns, but they are located in non-homologous positions. P56 and P59 show significant protein sequence similarity to pectate lyases of plant pathogenic bacteria. The similarity of P56 and P59 to the bacterial pectate lyases is equivalent to the homology described for different pectate lyase sequences of the genus Erwinia. We suggest that the pollen expression of LAT56 and LAT59 might relate to a requirement for pectin degradation during pollen tube growth.

Amino Acid Sequence↗
PubMed1990

Pollen-specific gene expression in transgenic plants: coordinate regulation of two different tomato gene promoters during microsporogenesis.

To investigate the regulation of gene expression during male gametophyte development, we analyzed the promoter activity of two different genes (LAT52 and LAT59) from tomato, isolated on the basis of their anther-specific expression. In transgenic tomato, tobacco and Arabidopsis plants containing the LAT52 promoter region fused to the beta-glucuronidase (GUS) gene, GUS activity was restricted to pollen. Transgenic tomato, tobacco and Arabidopsis plants containing the LAT59 promoter region fused to GUS also showed very high levels of GUS activity in pollen. However, low levels of expression of the LAT59 promoter construct were also detected in seeds and roots. With both constructs, the appearance of GUS activity in developing anthers was correlated with the onset of microspore mitosis and increased progressively until anthesis (pollen shed). Our results demonstrate co-ordinate regulation of the LAT52 and LAT59 promoters in developing microspores and suggest that the mechanisms that regulate pollen-specific gene expression are evolutionarily conserved.

Chimera↗
PubMed1990

A role for high-dose antipsychotics.

The authors present a series of cases demonstrating that some chronically psychotic patients require higher doses of antipsychotic medication (greater than 15 mg/day of haloperidol equivalents) than are currently in vogue as a result of research on low-dose treatment. In a random sample of 100 patients treated with psychotropic medication, 64 were treated with antipsychotics. Of these, 8 (12.5%) appeared to require high doses. The literature on low-dose treatment is reviewed, and the role of higher-dose therapy is placed in perspective.

Adult↗
PubMed1989

Isolation and expression of an anther-specific gene from tomato.

We have isolated and sequenced an anther-specific cDNA clone and a corresponding genomic clone from tomato. The gene (LAT52) encodes an 800-nucleotide-long transcript that is detectable in pollen, anthers and at 20- to 50-fold lower levels in petals. LAT52 mRNA is not detectable in pistils, sepals or non-reproductive tissues. Steady-state levels of LAT52 mRNA are detectable in immature anthers containing pollen at the tetrad stage and increase progressively throughout microsporogenesis until anthesis (pollen shed). The LAT52 gene contains 5' and 3' untranslated regions of 110 and approximately 150 nucleotides, respectively, and a single intron with a highly repetitive sequence. A TATA box motif is located 28 nucleotides upstream of the transcription start site. The gene encodes a putative protein of 18 kDa that is cysteine rich and has an N-terminal hydrophobic region with characteristics similar to eucaryotic secretory signal sequences. LAT52 is a single or low copy gene in tomato and shares homology with sequences in tobacco.

Amino Acid Sequence↗
PubMed1989

Gametophytic and sporophytic expression of anther-specific genes in developing tomato anthers.

The tissue localization of transcripts corresponding to five anther-specific cDNA clones isolated from tomato was determined. Transcripts specified by three of the cDNA clones were first detectable in anthers containing mitotic-stage gametophytes and were localized to the gametophyte. Transcripts specified by the two other cDNA clones were not detectable until anthers had reached a later developmental stage; these transcripts were also localized to the (now bicellular) gametophytes. Transcript levels for all of the cDNAs increased during gametogenesis and reached maximal levels in mature pollen grains. These mRNAs persisted in in vitro-grown pollen tubes, concentrating toward the tips of the growing tubes. At flower maturity, transcripts specified by each of the cDNAs were also detected in the epidermal and endothecial cell layers of the anther wall. The spatial distribution of transcripts in the anther wall was confined to that region of the anther that surrounds the locule. Transcripts were not detected in the sterile tip of the anther or in the filament. mRNA levels for these cDNA clones were markedly reduced in the anthers of several independent male-sterile mutants of tomato. Our results provide evidence that these anther-specific cDNAs represent genes expressed in both the gametophytic and sporophytic phases of the plant life cycle. The patterns of mRNA accumulation observed support the hypothesis that the proteins encoded by these genes function during pollen development and pollen tube growth.

DNA↗
PubMed1989

5-Hydroxytryptamine uptake in oxygen radical-mediated acute lung injury.

Pulmonary endothelial cell function (ECF) studies have been shown to be a sensitive indicator of chronic lung injury. We attempted to correlate changes in 5-hydroxytryptamine (5HT) uptake with an acute oxygen radical-mediated lung injury in dogs. Beta-d glucose/glucose oxidase was injected intravenously in an experimental group (n = 10), while the control group (n = 5) received saline. 5HT uptake, measured using a multiple indicator dilution technique before and 20 min after injection, was calculated for both the percent total uptake and the peak extraction ratio of 5HT during a single passage through the lung. The mean pulmonary and systemic arterial pressures (PAP, SAP), total pulmonary resistance (TPR), extravascular lung water (EVLW), and wet-to-dry weight ratios were also determined. The experimental group showed an acute rise in PAP and TPR and a fall in SAP after the injection, all returning to normal by 20 min; total 5HT uptake fell from 81 +/- 2.3% to 47 +/- 6.5% (p = 0.0002) as did the peak extraction ratio from 0.87 +/- 0.013 to 0.44 +/- 0.066 (p = 0.0001). No change in 5HT uptake was observed in the control group. EVLW did not change in either group, but wet-to-dry weight ratio was elevated in the experimental group (5.21 +/- 0.12 versus 4.73 +/- 0.06, p less than 0.01). ECF studies of 5HT uptake appear to be a sensitive indicator of acute lung injury in this large-animal, oxygen radical-induced injury model.

Acute Disease↗
PubMed1988

Influence of collagen gel substratum on response to low-density lipoprotein by cultured human skin fibroblasts.

The effect of low-density lipoprotein (LDL) on accumulation of glycosaminoglycans (GAG) was compared in cultures of human skin fibroblasts on a conventional plastic substratum and in a native type I collagen gel. The 24-h incorporation of [3H]glucosamine and Na2(35)SO4 into GAG secreted into the medium or associated with the substratum and cell surface (SCA) was measured in cells at subconfluent densities. When cells were grown on plastic, 13-25% of the labeled GAG was in the SCA pool. Cells cultured within a collagen gel matrix incorporated three times more [3H]glucosamine and up to five times more [35S]sulfate into this pool. The addition of LDL (300 micrograms protein/mL) to the medium increased the level of total GAG incorporation of [3H]glucosamine by 40-50% and of [35S]sulfate by 15-20% on both substrata. For cells on plastic the relative increase in the medium and SCA pool was similar, whereas for cells in collagen gel the response to LDL was twice as great in the SCA pool as in the medium. The distribution of GAG types was unaffected by LDL; hyaluronic acid remained the principal GAG in the media pools of both substrata, heparan sulfate remained the main SCA GAG in cultures on plastic, and dermatan sulfate remained the dominant GAG in the SCA pool of collagen gel cultures. LDL degradation was measured at intervals up to 48 h after the addition of 125I-labeled LDL. The rate of accumulation of degraded LDL products was lower in collagen gel cultures, but the final levels achieved were the same in the two substrata. Concentrations of total cell cholesterol were similar, although the increases in free cholesterol induced by LDL were 26% greater in cells within collagen gel than in those on plastic. We conclude that fibroblasts grown within a collagen gel, as compared with those on a plastic substratum, (i) accumulate more GAG that remain attached to the substratum and cell surface; (ii) respond to LDL with a similar degree of increase in GAG accumulation, but more of the increase is found in the substratum and cell surface compartment; and (iii) accumulate more intracellular free cholesterol in response to LDL.

Cells, Cultured↗