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Full-Text Articles in Life Sciences
Molecular Genetic Analysis Of Terminal Steps In Bacteriochlorophyll A Biosynthesis: Characterization Of A Rhodobacter Capsulatus Strain That Synthesizes Geranylgeranoil-Esterified Bacteriochlorophyll A, David Bollivar, Shaojie Wang, James P. Allen, Carl E. Bauer
Molecular Genetic Analysis Of Terminal Steps In Bacteriochlorophyll A Biosynthesis: Characterization Of A Rhodobacter Capsulatus Strain That Synthesizes Geranylgeranoil-Esterified Bacteriochlorophyll A, David Bollivar, Shaojie Wang, James P. Allen, Carl E. Bauer
David Bollivar
Site-directed mutational analysis of the Rhodobacter capsulatus photosynthesis gene cluster was undertaken in order to identify and characterize genetic loci involved in bacteriochlorophyll a biosynthesis. A mutant in orf304 was shown to accumulate the tetrapyrrole intermediate "bacteriochlorophyllide a" which is a tetrapyrrole that has a bacteriochlorophyll a ring structure without the presence of an esterifying alcohol. A mutant in orf391 is shown to synthesize acteriochlorophyll a that is esterified with geranylgeraniol rather than the normal phytol. This latter result provides the first genetic confirmation that esterification of bacteriochlorophyllide a initially involves the addition of a geranylgeraniol group followed by sequential …
Factors Affecting The Abundance Of Juvenile Fish Species On A Temperate Artificial Reef, Daniel Pondella, John Stephens
Factors Affecting The Abundance Of Juvenile Fish Species On A Temperate Artificial Reef, Daniel Pondella, John Stephens
Daniel Pondella
In contrast to most artificial reefs which are placed at relatively deep depths so as not to interfere with shipping, rocky breakwaters provide important habitat in the intertidal-shallow subtidal zone. This zone is especially preferred for recruitment by many rocky shore fishes. The breakwaters of King Harbor, Redondo Beach, California enhance this zone. Further, the lee of the outer breakwater provides a stable, quiet water area for numerous Young-of-Year (YOY) fishes. By means of SCUBA we monitored YOY abundance from 1986-1990. During these five years there were dramatic natural and anthropogenic disturbances of the habitat. With little inter-annual variation of …
Heterologous Expression Of The Bchm Gene Product From Rhodobacter Capsulatus And Demonstration That It Encodes S-Adenosyl-L-Methionine: Mg-Protoporhyrin Ix Methyltransferase, David Bollivar, Ze-Yu Jiang, Carl E. Bauer, Samuel I. Beale
Heterologous Expression Of The Bchm Gene Product From Rhodobacter Capsulatus And Demonstration That It Encodes S-Adenosyl-L-Methionine: Mg-Protoporhyrin Ix Methyltransferase, David Bollivar, Ze-Yu Jiang, Carl E. Bauer, Samuel I. Beale
David Bollivar
The bacteriochlorophyll biosynthesis gene, bchM, from Rlodobacter capsulatus was previously believed to code for a polypeptide involved in formation of the cyclopentone ring of protochlorophyllide from Mg-protoporphyrin IX monomethyl ester. In this study, R. capsulatus bchM was expressed in Escherichia coli and the gene product was subsequently demonstrated by enzymatic analysis to catalyze methylation of Mg-protoporphyrin IX to form Mg-protoporphyrin IX monomethyl ester. Activity required the substrates Mg-protoporphyrin IX and S-adenosyl-L-methionine. 14C-labeled product was formed in incubations containing 14C-methyl-labeled S-adenosyl-L-methionine. On the basis of these and previous results, we also conclude that the bchH gene, which was previously reported to …
Proceedings Of The Third Rhode Island Shellfish Industry Conference, Michael Rice, Elizabeth Gibbs
Proceedings Of The Third Rhode Island Shellfish Industry Conference, Michael Rice, Elizabeth Gibbs
Michael A Rice
Collections of various papers presented at the conference
Protein S-Thiolation In Hepatocytes Stimulated By T-Butyl Hydroperoxide, Menadione, And Neutrophils, Yuh-Cherng Chai, S. Hendrich, James Thomas
Protein S-Thiolation In Hepatocytes Stimulated By T-Butyl Hydroperoxide, Menadione, And Neutrophils, Yuh-Cherng Chai, S. Hendrich, James Thomas
Yuh-Cherng Chai
In order to examine potentially important S-thiolated proteins, ^3^5S-labeled hepatocytes were exposed to oxidative stress. A similar group of S-thiolated proteins including carbonic anhydrase III was observed in cells treated with t-butyl hydroperoxide, menadione, or stimulated neutrophils. The radioactive thiols bound to hepatocyte proteins were identified by HPLC and more than 85% was glutathione. In menadione-treated hepatocytes, proteins were gradually S-thiolated over 30 min and 25% of the cellular glutathione pool became protein-bound. In t-butyl hydroperoxide-treated cells, S-thiolation was more transient and 11% of the glutathione was protein-bound. Neutrophil-treated hepatocytes had nearly the same amount of protein S-thiolation (8% after …
S-Thiolation Of Individual Human Neutrophil Proteins Including Actin By Stimulation Of The Respiratory Burst: Evidence Against A Role For Glutathione Disulfide, Yuh-Cherng Chai, S. Ashraf, R. Johnson, James Thomas
S-Thiolation Of Individual Human Neutrophil Proteins Including Actin By Stimulation Of The Respiratory Burst: Evidence Against A Role For Glutathione Disulfide, Yuh-Cherng Chai, S. Ashraf, R. Johnson, James Thomas
Yuh-Cherng Chai
Protein S-thiolation, a reversible modification of protein sulfhydryls resulting in formation of mixed-disulfides, was studied in human neutrophils stimulated with phorbol diester to produce superoxide anion. Rapid S-thiolation of several proteins was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Glutathione was identified as the primary protein-bound thiol by HPLC chromatography, contributing considerably more than 85% of the total. Minor amounts of homocysteine and/or cysteine were also detected as protein-bound thiols. During the first 30 min after stimulation, 10% of the cellular glutathione became protein bound (2 nmol/mg of protein). There was no increase in glutathione disulfide suggesting that S-thiolation of …
Heterochronic Genes And The Temporal Control Of C. Elegans Development, Victor Ambros, Eric Moss
Heterochronic Genes And The Temporal Control Of C. Elegans Development, Victor Ambros, Eric Moss
Victor R. Ambros
The heterochronic genes of Caenorhabditis elegans encode part of a regulatory system that controls the temporal component of cell fates in development. The genes have been characterized genetically and molecularly, and their study has so far revealed a genetic hierarchy that specifies sequences of developmental events, a novel RNA-mediated mechanism of gene regulation and a reprogramming phenomenon associated with arrested development.
Irreversible Steps In The Ferritin Synthesis Induction Pathway.., L. Linggoess, David Mascotti, M. Bhattacharyya-Pakrasi, H. Gang, R. Thach
Irreversible Steps In The Ferritin Synthesis Induction Pathway.., L. Linggoess, David Mascotti, M. Bhattacharyya-Pakrasi, H. Gang, R. Thach
David P. Mascotti
The ability of cells to re-repress ferritin synthesis after removal of an inducing agent (iron or heme) was investigated. Re-repression was found to be a slow process, requiring approximately 4 (after iron removal) to 10 h (after heme removal) for completion. Desferrioxamine mesylate (Desferal) had only a slight effect on the rate of re-repression, whereas cycloheximide was strongly inhibitory, indicating that new protein synthesis is required for re-repression. Re-repression occurred at a slow but significant rate in the presence of both Desferal and cycloheximide. These results indicate that, in the absence of an iron chelator, the induction of ferritin synthesis …
Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung
Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung
Yuh-Cherng Chai
No abstract provided.
Water Potentials For Developing Cladodes And Fruits Of A Succulent Plant, Including Xylem-Versus-Phloem Implications For Water Movement, P. Nobel, J. Andrade, N. Wang, Gretchen North
Water Potentials For Developing Cladodes And Fruits Of A Succulent Plant, Including Xylem-Versus-Phloem Implications For Water Movement, P. Nobel, J. Andrade, N. Wang, Gretchen North
Gretchen North
Developing cladodes had lower water potentials and developing fruits had higher water potentials than the underlying cladodes of the widely cultivated prickly pear cactus, Opuntia ficus-indica. The 0.06 MPa lower value in 4-week-old daughter cladodes indicated a typical water potential gradient from the underlying clad-ode along the xylem of −0.2 MPa m−1; the 0.17 MPa higher value in 4-week-old fruits, which decreased to 0.07 MPa by 10 weeks, implicated the phloem as their supplier of water. The phloem sap of the underlying cladodes had an osmotic pressure of only 0.90 to 0.98 MPa, so the phloem could supply a relatively …
S-Thiolation And Irreversible Oxidation Of Sulfhydryls On Carbonic Anhydrase Iii During Oxidative Stress: A Method For Studying Protein Modification In Intact Cells And Tissues, C. Lii, Yuh-Cherng Chai, W. Zhao, James Thomas, S. Hendrich
S-Thiolation And Irreversible Oxidation Of Sulfhydryls On Carbonic Anhydrase Iii During Oxidative Stress: A Method For Studying Protein Modification In Intact Cells And Tissues, C. Lii, Yuh-Cherng Chai, W. Zhao, James Thomas, S. Hendrich
Yuh-Cherng Chai
No abstract provided.
Changes In Root Hydraulic Conductivity For Two Tropical Epiphytic Cacti As Soil Moisture Varies, Gretchen North, P. Nobel
Changes In Root Hydraulic Conductivity For Two Tropical Epiphytic Cacti As Soil Moisture Varies, Gretchen North, P. Nobel
Gretchen North
The tropical epiphytic cacti Epiphyllum phyllanthus and Rhipsalis baccifera experience extreme variations in soil moisture due to limited soil volumes and episodic rainfalls. To examine possible root rectification, whereby water uptake from a wet soil occurs readily but water loss to a dry soil is minimal, responses of root hydraulic conductivity (Lp) to soil drying and rewetting were investigated along with the underlying anatomical changes. After 30 d of soil drying, Lp decreased 50%-70% for roots of both species, primarily because increased suberization of the periderm reduced radial conductivity. Sheaths composed of soil particles, root hairs, and mucilage covered young …
Cladode Development For Opuntia Ficus-Indica (Cactaceae) Under Current And Doubled Co2 Concentrations, Gretchen North, T.L. Moore, P.S. Nobel
Cladode Development For Opuntia Ficus-Indica (Cactaceae) Under Current And Doubled Co2 Concentrations, Gretchen North, T.L. Moore, P.S. Nobel
Gretchen North
Morphological and anatomical changes for first-order daughter cladodes (flattened stem segments) of a prickly pear cactus, Opuntia ficus-indica, were monitored to determine the effects of a doubled atmospheric CO2 concentration on their development and mature form. For daughter cladodes developing in controlled environment chambers for 60 d, maximal elongation rates were similar under a photosynthetic photon flux density (PPFD) of 6 mol m-2 d-1 and a CO2 concentration of 370 μl liter-1, an increased PPFD (10 mol m-2 d-1), and an increased PPFD and a doubled CO2 concentration. These maximal rates, however, occurred at 20, 15, and 12 d, respectively. …