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R L Fischer

Publications and source records attributed to R L Fischer.

65 records · Page 4Linked to original sources
PubMed1989

Molecular characterization of an aberrant allele for the Gy3 glycinin gene: a chromosomal rearrangement.

The soybean variety Forrest contains an aberrant allele for the Gy3 glycinin gene. The aberrant allele is designated gy3 because mRNA for the G3 glycinin subunit is reduced to below detectable amounts in the seed. Molecular and genetic characterization of gy3 show it to be associated with a chromosomal rearrangement that causes the 5' halves and 3' halves of the gene to become separated from one another in the genome. An inversion is the simplest structural model that accounts for the genetic and molecular features of the chromosomal rearrangement involving gy3, although more complex models that involve reciprocal translocations are also consistent with the data.

Alleles↗
PubMed1988

Interaction of a DNA binding factor with the 5'-flanking region of an ethylene-responsive fruit ripening gene from tomato.

To understand how fruit development is controlled, we have begun experiments to identify DNA sequences and proteins that regulate gene expression during tomato (Lycopersicon esculentum) fruit ripening. We have focused on the E8 gene because its transcription is responsive to ethylene hormone and is activated at the onset of fruit ripening. We report here that sequences required for ethylene-responsive and developmentally regulated E8 gene expression in transgenic tomato plants are contained on a 4.4 kb restriction fragment which includes sequences 2 kb 5' and 0.5 kb 3' to the gene. In addition, we have identified a DNA-binding factor that specifically interacts with DNA sequences that flank the E8 gene. This DNA-binding activity is low in unripe fruit and increases during fruit ripening. This factor also binds to the 5'-flanking region of another ethylene-responsive gene which is coordinately expressed during tomato fruit ripening. These data suggest that the DNA binding-factor may be involved in the regulation of gene expression during fruit ripening.

Base Sequence↗
PubMed1988

Diverse mechanisms for the regulation of ethylene-inducible gene expression.

We have investigated the mechanism of action of the plant hormone ethylene by analyzing the expression of ethylene-inducible genes isolated from tomato (Lycopersicon esculentum). We have found that the expression of each cloned gene is regulated by ethylene in a unique manner. That is, for certain genes ethylene affects transcriptional processes, while for another gene it affects both transcriptional and post-transcriptional processes. Furthermore, induction of gene transcription by ethylene is organ specific for one gene, while for others it is not. In addition, we have measured gene expression as a function of ethylene concentration and have found that each gene displays a unique ethylene dose-response curve. Our results suggest that ethylene modulates gene expression by a variety of mechanisms.

Dose-Response Relationship, Drug↗
PubMed1988

Ethylene-regulated expression of a tomato fruit ripening gene encoding a proteinase inhibitor I with a glutamic residue at the reactive site.

We report the isolation from tomato (Lycopersicon esculentum) of an ethylene-responsive member of the proteinase inhibitor gene family. DNA sequence analysis of a full-length cDNA clone indicates that the ethylene-responsive gene is distantly related to the tomato proteinase inhibitor I gene, having 53% sequence identity. The predicted amino acid sequence reveals 47% and 45% sequence identity with the tomato and potato proteinase inhibitor I polypeptides, respectively. Additionally, the ethylene-responsive inhibitor has evolved a completely different pattern of gene expression and inhibitory specificity than other members of the inhibitor I family. Gel blot hybridization experiments show that, unlike the tomato proteinase inhibitor I gene, it is not induced in wounded leaves. In contrast, it is activated by the plant hormone ethylene in leaves and during fruit ripening. Furthermore, the ethylene-responsive inhibitor exhibits a novel reactive site, having glutamic acid as the P1 residue. This suggests that the ethylene-responsive proteinase inhibitor does not react with chymotrypsin, as does proteinase inhibitor I, but that it reacts with proteolytic enzymes that cleave at glutamic residues, such as the Staphylococcus aureus V8 proteinase, for which no inhibitors are known. Finally, isolation and analysis of a genomic clone reveals that the ethylene-responsive proteinase inhibitor gene is tightly linked to another, yet unidentified, coordinately expressed gene. We discuss these results with regard to the function and evolution of proteinase inhibitor genes in tomato.

Base Sequence↗
PubMed1988

Analysis of mRNAs that Accumulate in Response to Low Temperature Identifies a Thiol Protease Gene in Tomato.

We have studied the induction of gene expression at low temperature by cloning mRNAs that accumulate when unripe tomato (Lycopersicon esculentum) fruit are incubated at 4 degrees C. Two cloned mRNAs, C14 and C17, accumulate relatively rapidly in response to cold treatment, while a third, C19, displays a delayed response. Significant levels of these mRNAs were not detected during fruit ripening at normal temperature. We have analyzed gene expression at different temperatures and detect half-maximal accumulation of the C14 and C17 mRNAs at 16 degrees C and 11 degrees C, respectively, and have observed that sustained gene expression requires continuous cold treatment. Furthermore, the level of C14 and C17 gene expression in cold-tolerant (hybrid L. esculentum/Lycopersicon pimpinellifolium) fruit is different from that in cold-sensitive (L. esculentum) fruit. DNA sequence analysis indicates that the C14 mRNA encodes a polypeptide with a region that is homologous to the plant thiol proteases actinidin and papain and to the animal thiol protease cathepsin H. We conclude from these experiments that low temperature selectively induces the expression of specific genes and that one such gene encodes a thiol protease.

Journal Article↗
PubMed1988

Regulation of Gene Expression by Ethylene in Wild-Type and rin Tomato (Lycopersicon esculentum) Fruit.

Levels of ethylene biosynthesis and ethylene-inducible gene expression in wild-type tomato (Lycopersicon esculentum) fruit and in nonripening fruit from the tomato mutant rin (ripening inhibitor) were compared in order to investigate the mechanism of ethylene action. Whereas wild-type tomato fruit dramatically increase the rate of ethylene biosynthesis at the onset of ripening, rin fruit constitutively produce ethylene at a low basal level. We have compared the mRNA levels and transcription rates of four cloned ethylene-inducible genes (JE Lincoln, S Cordes, E Read, RL Fischer 1987 Proc Natl Acad Sci USA 84: 2793-2797) during wild-type and rin fruit development. In wild-type fruit, both mRNA levels and transcription rates of these genes increase. The effect of the rin mutation on gene expression is different for each ethylene-inducible gene. In one case expression is completely suppressed, while in other instances it is either partially inhibited or relatively unaffected by the mutation. The mRNA levels of each of these genes in response to exogenous ethylene in rin fruit was also measured. The mRNAs for all four genes accumulate to similar levels in both ethylene treated rin and ethylene treated wild-type fruit. These results are discussed with regard to the response of plants to ethylene hormone at the level of gene expression.

Journal Article↗
PubMed1988

Comparison of continuous epidural infusion of fentanyl-bupivacaine and morphine-bupivacaine in management of postoperative pain.

The short duration of epidural fentanyl has limited its direct comparison with epidural morphine in previous reports. The following study was performed of continuous postoperative epidural infusions at 5 ml/hr fentanyl 10 micrograms/ml (n = 59) or morphine 0.1 mg/ml (n = 48), both with bupivacaine 0.1%, in patients having cesarean sections. Postoperative evaluations included the frequency and magnitude of clinically evident respiratory depression, the adequacy of analgesia, nausea, pruritus, the ability to ambulate, and other side effects for 24 hours. Analgesia and the number of supplemental narcotic injections needed were similar in both groups. The incidence of nausea and pruritus was significantly less in the patients receiving fentanyl. No patient developed respiratory depression in either group. Patient and staff acceptance of the continuous epidural technique was excellent because there were only minor catheter-related problems associated with its use. It is concluded that continuous epidural fentanyl combined with bupivacaine offers excellent postoperative analgesia with minimal side effects.

Bupivacaine↗
PubMed1987

Regulation of gene expression by ethylene during Lycopersicon esculentum (tomato) fruit development.

We have investigated the regulation of gene expression by the plant hormone ethylene by cloning mRNAs that accumulate in unripe tomato fruit (Lycopersicon esculentum) exposed to exogenous ethylene. The response to exogenous ethylene is rapid; within 30-120 min we detect an increase in the cloned mRNA concentrations. DNA sequence analysis indicates that one of the ethylene-inducible genes is related to a gene encoding wound-inducible proteinase inhibitor I. We have measured ethylene production during fruit development and detect low basal levels in unripe fruit and much higher levels in ripening fruit. Blot hybridization experiments show that expression of the cloned genes is developmentally regulated by ethylene during fruit ripening: the mRNAs produced by these genes are more abundant in ripe fruit than in unripe fruit, and this mRNA accumulation is repressed by a competitive inhibitor of ethylene action, norbornadiene. However, during fruit development some of the cloned mRNAs begin to accumulate when ethylene production is at a basal level, whereas other mRNAs begin to accumulate later when the endogenous ethylene concentration increases, suggesting that gene expression during fruit development can be activated by ethylene in two ways. In some cases gene expression is primarily activated by an increase in sensitivity to basal ethylene levels, whereas in other cases it may be regulated by an increase in ethylene concentration.

Amino Acid Sequence↗
PubMed1982

Structure and flanking regions of soybean seed protein genes.

We have characterized the structure and flanking region of genes representing two, coordinately expressed, soybean seed protein gene families. One family directs the synthesis of the major storage protean glycinin; the other encodes a 15.5 kd polypeptide of unknown function. DNA blot hybridization experiments showed approximately three, nonallelic genes in the glycinin family and two in the 15 kd protein family, and showed that these families are not selectively amplified or rearranged during embryogeny. R-loop and S1 nuclease mapping studies demonstrated no detectable introns in the 15 kd protein genes but at least one and possibly two in the glycinin genes. No interfamily clustering of these genes occurs within a 10-15 kb chromosomal domain. Nor are they contiguous to other genes expressed at moderate levels during embryogenesis. Each of them, however, is contiguous to a gene expressed at another developmental period in the leaf. These leaf genes encode rare class messages which constitute only 1 X 10(-5%) of the leaf mRNA, or about one molecule per cell. R-loop analysis of two leaf genes showed that one contains no detectable introns while the other possesses at least three. DNA gel blot studies showed that only one of the seed protein genomic clones contains an interspersed repetitive DNA element. Pairwise cross-hybridization studies did not detect any flanking sequences shared by the 15 kd protein, glycinin and leaf genes.

Base Sequence↗
PubMedDate not supplied

Does light pressure effleurage reduce pain and anxiety associated with genetic amniocentesis? A randomized clinical trial.

OBJECTIVE: To determine if light pressure effleurage (leg rubbing) during genetic amniocentesis reduces procedure-related pain and anxiety. METHODS: Two hundred women with singleton gestations undergoing genetic amniocentesis between 15-22 weeks recorded their level of anticipated pain and anxiety on a 10-cm linear visual analog scale prior to the amniocentesis. Subjects were then randomized to receive effleurage or no effleurage by the assisting nurse during the procedure. Subjects were blinded to the effleurage nature of the study. Following the amniocentesis, subjects repeated the pain and anxiety scoring. RESULTS: The two groups were similar with respect to subject and procedure characteristics, as well as anticipated pain or anxiety prior to amniocentesis. Postamniocentesis pain and anxiety scoring were similar in the two groups. The mean effleurage acceptance score was 8.3 +/- 1.8 (out of 10), and 90.2% of subjects reported that they would want effleurage with future amniocenteses. CONCLUSIONS: Although well accepted by women, light pressure effleurage during genetic amniocentesis does not reduce procedure-related pain or anxiety.

Adult↗