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Biomedical subjects

M S Wright

Publications and source records attributed to M S Wright.

At least 19 recordsLinked to original sources
PubMed1992

Cloning strategies for peptide hormone receptors.

With the advancement in molecular biology in the last decade many receptors have been cloned and the understanding of their mechanism of function has improved proportionally. In addition the concurrent discovery of receptor gene families has been used to design elegant cloning strategies which in turn have facilitated the characterization of new receptors and receptor subtypes. This review covers the most currently used cloning strategies and gives some examples.

Animals↗
PubMed1992

Validation of a self-reported shelf inventory to measure food purchase behavior.

A mailed, self-reported shelf inventory was validated for use as a tool in assessing the impact of a community nutrition intervention that included a point-of-purchase component. The self-reported inventory was evaluated for overall accuracy as well as for the effects of gender, age, and shopping responsibility on accuracy. In addition, the food-shelf inventory was compared with a specific food frequency questionnaire. Specificity and sensitivity were calculated for self-reported inventories using an interviewer-completed, same-day inventory as the gold standard. Overall sensitivity was 86% and 87%, and overall specificity was 92% and 90% in two validation studies. Results show that the mailed, self-reported shelf inventory is a valid measure of the presence or absence of particular foods in households. As such, it may be a useful tool for assessing the impact of point-of-purchase nutrition interventions.

Adult↗
PubMed1991

Use of a lacZ fusion to study transcriptional regulation of the Rhodobacter capsulatus hemA gene.

An EcoRI fragment containing the Rhodobacter capsulatus hemA promoter has been cloned into a lacZ translational fusion vector. The resulting plasmid produced a hemA-lacZ fusion protein with a molecular mass of 147,000. Expression of the hemA-lacZ fusion, as measured by production of beta-galactosidase, was regulated 2- to 3-fold by oxygen tension. The unexpectedly small change in beta-galactosidase levels suggests that transcriptional regulation of the hemA gene is not the major factor in oxygen-mediated control of porphyrin synthesis.

5-Aminolevulinate Synthetase↗
PubMed1991

Immunocytochemical localization of leucomyosuppressin-like peptides in the CNS of the cockroach, Leucophaea maderae.

Immunocytochemistry was used to determine sites of synthesis and pathways for the transport of the neuropeptide, Leucomyosuppressin (pQDVDHVFLRFamide) in the cockroach, Leucophaea maderae. This study led to identification of neurons in the brain and thoracic ganglia reactive to polyclonal antibodies raised against this peptide. No immunoreactive cells were found in the subesophageal or abdominal ganglia. Although the corpus cardiacum contained no intrinsic cells immunoreactive to LMS antibodies, the periphery of this organ and that of the nervi corporis allati contain an abundance of LMS-reactive terminals.

Amino Acid Sequence↗
PubMed1991

Localization of leucomyosuppressin-like peptides in the central nervous system of the stable fly with immunocytochemistry.

An antiserum raised against leucomyosuppressin (LMS), the first insect neuropeptide shown to inhibit contraction of both visceral and skeletal muscles of insects, revealed the presence of LMS-like material in neurons of the adult stable fly, Stomoxys calcitrans (L.). Cells and their processes immunoreactive to the LMS antiserum were found in the brain, subesophageal, and thoracico-abdominal ganglia, with the majority of these neurons in the thoracico-abdominal ganglion. Positive immunostaining after preabsorption of the antibodies with the molluscan tetrapeptide FMRFamide, which absorbs the antibodies directed against the C-terminal FLRFamide of LMS, indicates that structural similarities between LMS and the stable fly neuropeptide(s) extend beyond a similar C-terminal tetrapeptide sequence.

Animals↗
PubMed1990

Different-sized mRNAs from GH4C1 cells induce a TRH-dependent electrical response in Xenopus laevis oocytes.

Poly(A)+ RNA from the GH4C1 rat pituitary cell line elicited a thyrotropin releasing hormone response in Xenopus laevis oocytes which could be measured as a change in membrane current by the voltage-clamp method. Oocytes injected with Poly(A)+ RNA from GH12C1 cells which do not bind thyrotropin releasing hormone or with buffer solution alone did not show this response. Size fractionation of total poly(A)+ RNA by sucrose density-gradient centrifugation shows two response maximal representing various mRNA fractions larger than 18S. These results indicate the presence of thyrotropin releasing hormone receptor mRNA heterogeneity where the smallest mRNA is at least 2 kb.

Animals↗
PubMed1988

Cloning of the Rhodobacter capsulatus hemA gene.

Portions of the Rhodobacter capsulatus hemA gene have been cloned from a hemA::Tn5 insertion strain into the lambda bacteriophage derivative EMBL3. A cosmid containing the wild-type R. capsulatus hemA gene was isolated by complementation of the hemA::Tn5 mutant. The cosmid contains a 1.4-kilobase EcoRI fragment that spans the hemA::Tn5 insertion site. The entire hemA gene is contained in this fragment and the adjacent 0.6-kilobase EcoRI fragment.

5-Aminolevulinate Synthetase↗
PubMed1987

Isolation and characterization of an aminolevulinate-requiring Rhodobacter capsulatus mutant.

Using transposon Tn5 mutagenesis, we isolated a mutant strain of Rhodobacter capsulatus that requires aminolevulinate for growth. Southern blot analysis indicated that this strain has a single Tn5 insertion. The addition of 0.1 mM aminolevulinate to the medium allowed the mutant to grow either aerobically or photosynthetically with generation times similar to those of the parental strain. When grown photosynthetically, bacteriochlorophyll accumulation increased with increasing aminolevulinate concentration. The mutant strain had only 10% of the normal aminolevulinate synthase activity, but it had a normal level of porphobilinogen synthase activity. The requirement for aminolevulinate could be satisfied by porphobilinogen, hemin, or protoporphyrin. While the mutant grew well on agar plates containing any of these substrates, growth in liquid media containing hemin or protoporphyrin was poor. Introduction of an R' factor containing all the known R. capsulatus bch genes into the mutant strain did not relieve the requirement for aminolevulinate, suggesting that the Tn5 insertion is not within the bch region.

Aminolevulinic Acid↗
PubMed1985

Distribution of calmodulin in insects as determined by radioimmunoassay.

The distribution of calmodulin in 11 separate tissues of the cockroach Leucophaea maderae was determined by radioimmunoassay. The highest levels of this protein were found in Malpighian tubules, visceral muscle and the central nervous system. Distribution of calmodulin was also determined for the following insect species: Apis mellifera, Canthon imitator, Heliothis zea (larvae) and Periplaneta americana. Abdominal tissues contained the highest levels of the calcium binding protein, while lesser amounts were found in the thorax and head. The detected levels of calmodulin suggest that this protein serves as an important regulator of biochemical functions in the viscera and nervous system of insects.

Animals↗