Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 11 of 11

Full-Text Articles in Life Sciences

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan Dec 1990

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan

Electronic Theses and Dissertations

A temperature-sensitive mutant of Escherichia coli affected in the alpha subunit of RNA polymerase has been investigated. Gene mapping and complementation experiments placed the mutation to temperature-sensitivity within the alpha operon at 72 min on the bacterial chromosome. The rate of RNA synthesis in vivo and the accumulation of ribosomal RNA were significantly reduced in the mutant at 44$\sp\circ$C. The thermostability at 44$\sp\circ$C of the purified holoenzyme from mutant cells was about 20% of that of the normal enzyme. Assays with T7 DNA as a template showed that the fraction of active enzyme competent ...


Nucleotide Sequence Of The Epsilon-Subunit Of The Mouse Muscle Nicotinic Acetylcholine Receptor, P D. Gardner Nov 1990

Nucleotide Sequence Of The Epsilon-Subunit Of The Mouse Muscle Nicotinic Acetylcholine Receptor, P D. Gardner

Open Dartmouth: Faculty Open Access Scholarship

The two predominant types of nicotinic acetylcholine receptors expressed in mammalian muscle differ with respect to a variety of electrophysiological and biochemical properties. A developmental, innervation-dependent switch in the subunit structure of the receptor, in which a y subunit is replaced by an E subunit, is thought to account, in large part, for these differences(1). Because of the interest in the regulatory mechanisms underlying this switch, much attention has focused on these two subunits. Here I report the nucleotide and deduced amino acid sequences of a clone coding for the mouse muscle E subunit isolated from a cDNA library ...


The Growth Of Simian Virus 40 (Sv40) Host Range/Adenovirus Helper Function Mutants In An African Green Monkey Cell Line That Constitutively Expresses The Sv40 Agnoprotein., Terryl P. Stacy, Michele Chamberlain, Susan Carswell, Charles N. Cole Jul 1990

The Growth Of Simian Virus 40 (Sv40) Host Range/Adenovirus Helper Function Mutants In An African Green Monkey Cell Line That Constitutively Expresses The Sv40 Agnoprotein., Terryl P. Stacy, Michele Chamberlain, Susan Carswell, Charles N. Cole

Open Dartmouth: Faculty Open Access Scholarship

The simian virus 40 T-antigen carboxy-terminal mutants, dlA2459 and dlA2475, are cell line and temperature dependent for growth and plaque formation in monkey kidney cells. Although these mutants did form plaques on BSC-1 cells at 37 degrees C, they were about fivefold less efficient for plaque formation than wild-type simian virus 40. These mutants did not grow in CV-1 cells and did not synthesize agnoprotein in those cells. CV-1 cells which constitutively express the agnoprotein were permissive for mutant plaque formation. However, late mRNAs, virion proteins, and progeny virion yields did not accumulate to wild-type levels during mutant infection of ...


Mutually Dependent Elements In The Neurotensin/Neuromedin N Gene Promoter Integrate Multiple Environmental Stimuli In Pc12 Cells: A Thesis, Edward H. Kislauskis Jun 1990

Mutually Dependent Elements In The Neurotensin/Neuromedin N Gene Promoter Integrate Multiple Environmental Stimuli In Pc12 Cells: A Thesis, Edward H. Kislauskis

GSBS Dissertations and Theses

This thesis examines the structure and regulated expression of the gene encoding the neuroendocrine peptides neurotensin and neuromedin N (NT/N gene). Previous studies have shown that expression of NT/N mRNA and NT peptide in PC12 cells are strictly dependent on simultaneous exposure to combinations of nerve growth factor (NGF), glucocorticoids, activators of adenylate cyclase, and lithium ion. My objective was to characterize the cis-regulatory DNA sequences involved in regulated expression of this gene.

The initial focus of this study was an analysis of the structure, tissue-specific expression, and exon evolution of the rat NT/N gene. Nucleotide sequence ...


Mechanism Of Escape Of Endogenous Murine Leukemia Virus Emv-14 From Recognition By Anti-Akr/Gross Virus Cytolytic T Lymphocytes., Hillary D. White, Michael D. Robbins, William R. Green Jun 1990

Mechanism Of Escape Of Endogenous Murine Leukemia Virus Emv-14 From Recognition By Anti-Akr/Gross Virus Cytolytic T Lymphocytes., Hillary D. White, Michael D. Robbins, William R. Green

Open Dartmouth: Faculty Open Access Scholarship

It was previously shown that spleen cells from endogenous ecotropic murine leukemia virus emv-14+ AKXL-5 mice fail to stimulate an anti-AKR/Gross virus cytolytic T-lymphocyte (CTL) response in a mixed lymphocyte culture with primed C57BL/6 responder spleen cells, whereas spleen cells from AKXL strains carrying the very similar emv-11 provirus do stimulate a response (Green and Graziano, Immunogenetics 23:106-110, 1986). We wished to determine whether the lack of response with AKXL-5 spleen cells was at the level of recognition between effector cell and target cell and whether the relevant mutation was within the emv-14 provirus. It is shown ...


Studies On The Maize Activator (Ac) Transposable Element In Transgenic Plants , James Hua Zhou Jan 1990

Studies On The Maize Activator (Ac) Transposable Element In Transgenic Plants , James Hua Zhou

Retrospective Theses and Dissertations

A series of plasmids, containing maize transposable element Activator (Ac), has been constructed. These constructs have been introduced into tobacco and soybean via Agrobacterium- mediated transformation to study the basic problems of Ac transposition, and plant cell lineages;An Ac element between a cauliflower mosaic virus 35S promoter and a bacterial [beta]-glucuronidase (GUS) reporter gene inactivates the reporter gene, and restores the reporter gene after its excision. Each sector histochemically stained arises from a single cell in which excision of the Ac element has restored GUS gene activity. Phloem and phloem parenchyma cells within vascular tissue of transgenic tobacco ...


A Genetic Study On The Activiation Of Quiescent Uq Transposable Elements In Zea Mays L. , Yong-Bao Pan Jan 1990

A Genetic Study On The Activiation Of Quiescent Uq Transposable Elements In Zea Mays L. , Yong-Bao Pan

Retrospective Theses and Dissertations

The standard a-ruq allele reports the activity of the Uq transposable element in the form of color spots or sectors of color spots in otherwise colorless aleurone tissue. As reported by this a-ruq, genomes of four maize inbred lines (C123, C103, B70 and 187-2) lack an active Uq element. However, these genomes contain quiescent Uq sequences that randomly and infrequently become activated;Spontaneous activation of quiescent Uq sequences during development of a-ruq/a-ruq/a-ruq endosperm results in sectors of Uq-a-ruq spotting in otherwise colorless aleurone tissue;Spontaneous germinal activation (at a rate of about 2 x 10[superscript]-4) of ...


Targeting Of Fusion Proteins To Organelles In Yeast And Tobacco: Investigation Of The Molecular Basis Of Toxin Susceptibility In Mitochondria Of Maize (Zea Mays L.) With The Texas Male-Sterile Cytoplasm , Jintai Huang Jan 1990

Targeting Of Fusion Proteins To Organelles In Yeast And Tobacco: Investigation Of The Molecular Basis Of Toxin Susceptibility In Mitochondria Of Maize (Zea Mays L.) With The Texas Male-Sterile Cytoplasm , Jintai Huang

Retrospective Theses and Dissertations

The T-URF13 protein from mitochondria of maize with the Texas male-sterile (cms-T) cytoplasm is implicated in the causation of cytoplasmic male sterility and sensitivity to host-specific fungal toxins produced by Helminthosporium maydis race T (HmT toxin) and Phyllosticta maydis (Pm toxin), as well as to the insecticide methomyl. Whether T-URF13 is responsible for toxin sensitivity in cms-T mitochondria was addressed. A chimeric gene coding for T-URF13 fused to the mitochondrial leader peptide from the Neurospora crassa ATP synthase subunit 9 precursor was expressed in the yeast Saccharomyces cerevisiae. The fusion protein encoded by this gene was translocated into the membrane ...


Genetic Analysis Of Deltex, A Gene Involved In The Development Of Drosophila Melanogaster , Maureen Joan Gorman Jan 1990

Genetic Analysis Of Deltex, A Gene Involved In The Development Of Drosophila Melanogaster , Maureen Joan Gorman

Retrospective Theses and Dissertations

The Notch gene is a member of one of the sets of genes that control the developmental pathways that specify cell fate decisions in Drosophila melanogaster. The goal of this research was to use a genetic approach to identify and characterize a gene that functions with Notch in a cell fate pathway. A candidate was found in a new mutation that causes phenotypes similar to Notch and that interacts phenotypically with Notch mutations. This mutation was identified as a mutation of the deltex gene. The deltex gene was mapped to the salivary chromosome band region 6AB. Mutant phenotypes in the ...


Genetic And Molecular Analyses Of Suppressor Of Forked In Drosophila Melanogaster , Cynthia Lynn Fitch-Steenson Jan 1990

Genetic And Molecular Analyses Of Suppressor Of Forked In Drosophila Melanogaster , Cynthia Lynn Fitch-Steenson

Retrospective Theses and Dissertations

Mutations at the suppressor of forked, su(f), locus are trans-acting, allele specific suppressors and enhancers of mutations at certain other loci. Su(f) is a trans-acting regulator whose normal product is necessary for proper transcription of these genes. The su(f) product regulates the transcription of transposable elements located within these genes. Our investigation includes a genetic analysis in which a number of new su(f) alleles were isolated, a development analysis in which the effects of new alleles and allelic combinations were characterized, and a molecular analysis in which a cloned genomic DNA fragment containing su(f) was ...


A Restriction Fragment Length Polymorphism Map Of Cochliobolus Heterostrophus , Tzy-Hwa Tzeng Jan 1990

A Restriction Fragment Length Polymorphism Map Of Cochliobolus Heterostrophus , Tzy-Hwa Tzeng

Retrospective Theses and Dissertations

An RFLP map was constructed for Cochliobolus heterostrophus, the causal agent of southern corn leaf blight, to facilitate the cloning of pathogenicity genes. A total of 128 RFLP and 4 phenotypic markers were analyzed. Of these, 126 were linked to other markers and delimited 944 cM, or, at a maximum, 58% of the total map length. Several RFLPs were found tightly linked to Tox1, a pathogenicity gene. A previously hypothesized translocation tightly linked to Tox1 was also detected;The numbers and sizes of the chromosomes of the two strains crossed to make the RFLP map were investigated using pulsed field ...