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Biology

1992

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Articles 271 - 280 of 280

Full-Text Articles in Life Sciences

An Examination And Correction Of Plant Tissue Culture Basal Medium Formulations, Henry R. Owen, A. Raymond Miller Jan 1992

An Examination And Correction Of Plant Tissue Culture Basal Medium Formulations, Henry R. Owen, A. Raymond Miller

Faculty Research & Creative Activity

The inorganic formulations of fourteen common plant tissue culture basal media were examined from the primary literature. Inaccuracies and errors were found for molecular formulae, chemical hydrations, and molar equivalences for iron/EDTA complexation. A comparison with published basal medium formulations from six commercial suppliers uncovered additional inaccuracies, modifications, and errors, thereby emphasizing the need for investigators to examine and describe medium formulations precisely in future publications.

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Modulation By Camp Of A Slowly Activating Potassium Channel Expressed In Xenopus Oocytes, Edward M. Blumenthal, Leonard K. Kaczmarek Jan 1992

Modulation By Camp Of A Slowly Activating Potassium Channel Expressed In Xenopus Oocytes, Edward M. Blumenthal, Leonard K. Kaczmarek

Biological Sciences Faculty Research and Publications

When expressed in the Xenopus oocyte, the minK protein induces a slowly activating voltage-dependent potassium current (Isk). We studied the modulation of this current by altering intracellular cAMP levels and found that the amplitude of Isk is dramatically increased by treatments that raise cAMP levels and decreased by agents that lower cAMP levels. Preinjection of a protein inhibitor of the cAMP-dependent protein kinase blocked the effects of increased cAMP levels. There were no changes in the voltage dependence or kinetics of Isk. Mutations that eliminate a potential phosphorylation site on the minK protein did …

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Experimental Manipulations Of The Organic Chemistry Of Seawater: Implications For Studies Of Energy Budgets In Marine Invertebrate Larvae, William Jaeckle Jan 1992

Experimental Manipulations Of The Organic Chemistry Of Seawater: Implications For Studies Of Energy Budgets In Marine Invertebrate Larvae, William Jaeckle

Scholarship

Correct measurement of changes in biomass and metabolic rates over time are two essential elements for the accurate construction of energy budgets for invertebrate larvae. Both components of larval energetics are altered by changes in the organic chemistry of the seawater. Axenic (bacteria-free) veliger larvae (88 µm shell length) of the bivalve Crassostrea gigas (Thunberg, 1795) had a 53% enhancement of their metabolic rate relative to control values (5.8 ± 0.6 pmol larva -1 h -1 , x¯ ± 1 SE) when exposed to seawater to which 1 µM glucose had been added. Gastrulae increased their rate of respiration by …

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Individualistic Perspectives On Plant Competition, Nancy J. Huntly Jan 1992

Individualistic Perspectives On Plant Competition, Nancy J. Huntly

Biology Faculty Publications

No abstract provided.

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Metabolite Production By Entomopathogenic Fungi, Donald W. Roberts, Raymond J. St. Leger, Sandeep Gupta Jan 1992

Metabolite Production By Entomopathogenic Fungi, Donald W. Roberts, Raymond J. St. Leger, Sandeep Gupta

Biology Faculty Publications

The entomopathogenic fungi produce a wide assortment of metabolites, some of which are important to the host-specialization of this group of fungi. Very few entomopathogenic fungi have been examined in detail for their metabolites in the disease process. Nevertheless, it is clear that certain proteases and lipases are crucial to the invasion of insect cuticle by the fungus. These fungi have the unusual ability to hydrolyze branched alkanes. Also, they normally produce very active, broad-spectrum proteases. These are needed for penetration of the hydrophobic epicuticle and the highly proteinaceous cuticle of insects. Chitinases also are involved, but usually have only …

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Creation Of A Vector For Regulated Expression Of Antisense Rna In Escherichia Coli, Wen-Jun Wu Jan 1992

Creation Of A Vector For Regulated Expression Of Antisense Rna In Escherichia Coli, Wen-Jun Wu

Masters Theses & Specialist Projects

A plasmid (pGEM-SD) was constructed in which the Shine-Dalgarno sequence had been deleted from pGEM-7zf(+) plasmid to generate a vector for regulated expression of antisense RNA. The binding of antisense RNA to mRNA provides a potent mechanism by which specific transcripts can be translationally inactivated. Although part of the lac operator sequence was deleted in pGEM-SD plasmid, it was proven that mRNA still can be induced under the control of lac promoter. Recombinant plasmids were generated by ligating bacterial genornic DNA into pGEM-SD plasmid, but the orientation of the inserted gene with respect to the lac promoter has not been …

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Biochemical Systematics Of Notothenioid Fishes From Antarctica, Mara A. Mcdonald, Michael H. Smith, Michael W. Smith, James M. Novak, Paul E. Johns, Arthur L. Devries Jan 1992

Biochemical Systematics Of Notothenioid Fishes From Antarctica, Mara A. Mcdonald, Michael H. Smith, Michael W. Smith, James M. Novak, Paul E. Johns, Arthur L. Devries

Faculty Research & Creative Activity

Genetic variation at 30 protein-coding loci was examined in seven forms of notothenioid fishes from Antarctica. Multilocus heterozygosity varied from 0.018 to 0.078 across taxa. An analysis of the allozyme data revealed the probable existence of an unrecognized cryptic species within Trematomu5 bemacchii. Pagothenia borchgrevinki is as closely related to some species of Trematomus as are some species of Trematomus to each other. Speciation among the species of Trematomus and Pagothenia appears to have taken place primarily after the separation of Antarctica from Australia.

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Fluorescence Quenching In The Varied Photosynthetic Modes Of Portulacaria Afra (L.) Jacq, Lonnie J. Guralnick, Guillermo Goldstein, Robert L. Heath, Irwin P. Ting Jan 1992

Fluorescence Quenching In The Varied Photosynthetic Modes Of Portulacaria Afra (L.) Jacq, Lonnie J. Guralnick, Guillermo Goldstein, Robert L. Heath, Irwin P. Ting

Arts & Sciences Faculty Publications

No abstract provided.

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The Costs Of Female Choice In A Lekking Bird, Robert M. Gibson, Gwendolyn C. Bachman Jan 1992

The Costs Of Female Choice In A Lekking Bird, Robert M. Gibson, Gwendolyn C. Bachman

School of Biological Sciences: Faculty Publications

We investigated the costs of active female choice in sage grouse, Centrocercus urophasianus, a lekking species in which females make repeated, lengthy visits to leks to assess males before mating. Several potential costs were measured by monitoring changes in hens' ranging behavior, time budgets, and encounter rates with predators when they visited leks. Two costs were identified: hens moved further per day and encountered golden eagles, Aquila chrysaetos, more frequently when visiting leks. However, extra travel due to visiting leks increased predicted daily energetic expenditure by only about 1%, and the risk of predation by golden eagles over …

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The Morphology, Physiology, And Fine Structure Of A Toluene-Oxidizing Strain Of Pseudomonas Putida, Barry Clayton Anderson Jan 1992

The Morphology, Physiology, And Fine Structure Of A Toluene-Oxidizing Strain Of Pseudomonas Putida, Barry Clayton Anderson

Dissertations and Theses

The role of microorganisms in the degradation of xenobiotics in the environment is well established. Bacteria from the genus Pseudomonas are particularly well adapted to the degradation of hydrocarbons, aromatics, and numerous other natural and introduced substrates. We have isolated a strain of Pseudomonas putida, designated PC2P15, that uses toluene, phenol, benzene, and a number of other substrates as its sole sources of carbon and energy.

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