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Articles 1 - 9 of 9

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Nonequilibrium Thermodynamic Approach To Biological Energy Conversion Systems , Michael K. Dowd Jan 1986

A Nonequilibrium Thermodynamic Approach To Biological Energy Conversion Systems , Michael K. Dowd

Retrospective Theses and Dissertations

Energy conversion devices are commonly built from individual subunits in order to increase the force or flow that can be obtained from the device. Examples occur in both engineering and biology and include the cylinders of an internal combustion engine, the plates of a battery, the cross-bridges of muscle, and the active transport complexes in a cell membrane;This work describes the behavior of assemblies of individual energy converting subunits. The linear phenomenological laws of nonequilibrium thermodynamics are used as constitutional equations that describe the relationship between the forces and flows of a subunit. These relationships along with the restrictions ...


Reduction Of Methemerythrin In The Erythrocytes Of Phascolopsis Gouldii , Ron E. Utecht Jan 1986

Reduction Of Methemerythrin In The Erythrocytes Of Phascolopsis Gouldii , Ron E. Utecht

Retrospective Theses and Dissertations

The non-heme oxygen carrier hemerythrin (Hr) undergoes autooxidation to give metHr, Fe(III),Fe(III) , a form that will not function in oxygen storage or transport. A methemerythrin reduction system has been isolated from the erythrocytes of the sipunculid Phascolopsis gouldii that reduces metHr to deoxyHr, Fe(II),Fe(II) , the active form in oxygen transport and storage. This methemerythrin reduction system is composed of cytochrome b(,5) and cytochrome b(,5) reductase with NADH acting as the source of electrons;EPR has shown the involvement of a one-electron reduction pathway for metHr in intact erythrocytes. Erythrocytes that have been ...


19f Nmr Studies Of 5-Fluorouracil-Substituted Escherichia Coli Transfer Rnas: Solution Structure And Codon-Anticodon Interaction , Paul Dennis Gollnick Jan 1986

19f Nmr Studies Of 5-Fluorouracil-Substituted Escherichia Coli Transfer Rnas: Solution Structure And Codon-Anticodon Interaction , Paul Dennis Gollnick

Retrospective Theses and Dissertations

('19)F NMR was used to study E. coli tRNA(,1)('Val), tRNA(,f)('Met), and tRNA(,m)('Met), in which 5-fluorouracil (FUra) has replaced uracil and uracil-derived minor bases. ('19)F NMR spectra of these tRNAs resolve resonances from nearly all the incorporated FUra residues. Each of the three tRNAs can be resolved into two isoaccepting species, termed forms A and B, whose ('19)F spectra differ in the shift of one ('19)F peak from ca. 4.5 ppm in form B, upfield to -15 ppm in form A. Because the two isoacceptors of each tRNA differ only ...


S-Thiolation Of Cytoplasmic Cardiac Proteins In Vivo , Mark William Collison Jan 1986

S-Thiolation Of Cytoplasmic Cardiac Proteins In Vivo , Mark William Collison

Retrospective Theses and Dissertations

Beating neonatal heart cell cultures were treated with diamide or t-butyl hydroperoxide (tBuOOH), and changes in glutathione oxidation, cell beating, and protein S-thiolation (protein mixed-disulfide formation) were examined. Both compounds caused extensive oxidation of glutathione. Cells treated with diamide stopped beating within 2 min, and beating returned to normal after 30-45 min. Cells stopped beating 25 min after addition of tBuOOH, and beating did not resume. tBuOOH caused S-thiolation of a variety of proteins, but only one protein, of molecular mass 23 kDa, was extensively modified. Diamide caused extensive modification of proteins with molecular masses of 97, 42, and 23 ...


Interaction Of Calmodulin And Ophiobolin A, A Fungal Phytotoxin , Pak Chow Leung Jan 1986

Interaction Of Calmodulin And Ophiobolin A, A Fungal Phytotoxin , Pak Chow Leung

Retrospective Theses and Dissertations

Ophiobolin A, a fungal phytotoxin which can stimulate the net leakage of electrolytes and glucose from maize seedling roots, is a potent inhibitor of calmodulin. The inhibition at pH 7.0 is time-dependent and could not be reversed by dialysis, dilution, nor denaturation, and was more pronounced in the presence than in the absence of Ca('2+). The direct interaction between ophiobolin A and calmodulin is shown by the quenching of the intrinsic tyrosine fluorescence of bovine brain calmodulin upon the addition of ophiobolin A. Maize calmodulin, reacted with ophiobolin A, has a smaller electrophoretic mobility than untreated calmodulin. Ophiobolin ...


The Heat Shock Response In Tetrahymena Thermophila: Control Of Protein Synthesis , Kevin W. Kraus Jan 1986

The Heat Shock Response In Tetrahymena Thermophila: Control Of Protein Synthesis , Kevin W. Kraus

Retrospective Theses and Dissertations

The changes in protein synthesis which result when Tetrahymena thermophila cells are shifted from 30(DEGREES)C to 40(DEGREES)C are shown to be regulated at both the mRNA accumulation and mRNA translation levels. The heat shock protein mRNAs are preferentially translated early in a heat shock while non-heat shock protein messages remain in the cell in a non-translated state. Later in heat shock these non-hsp messages return to polysomes at the same time as a small heat-induced RNA becomes associated with polysomal ribosomes. This novel RNA species may play an important role in the return to normal protein ...


Interaction Of Tgf-[Beta], Egf, And Tpa In Their Effects On The Production Of Secreted Proteins By Mouse 3t3 Cells And Human Fibroblasts , Chia-Ping Chiang Jan 1986

Interaction Of Tgf-[Beta], Egf, And Tpa In Their Effects On The Production Of Secreted Proteins By Mouse 3t3 Cells And Human Fibroblasts , Chia-Ping Chiang

Retrospective Theses and Dissertations

Growth regulators such as epidermal growth factor (EGF), fibroblast growth factor (FGF), 12-O-tetradecanoylphorbol 13-acetate (TPA), and type (beta) transforming growth factor (TGF-(beta)) regulate the production of certain proteins by cells in culture. EGF and TPA increased the secreted and intracellular levels of Mitogen-Regulated Protein (MRP) and Major Excreted Protein (MEP) by Swiss 3T3 cells. MRP is related by sequence to prolactin. MEP is a thiol protease located intracellularly in the lysosomes. EGF, FGF, and TPA also selectively induced a 52,000-dalton Mitogen-Induced Protein (MIP52) secreted by human fibroblasts. Two types of TGF-(beta)s were tested for their effects ...


Properties Of Retinyl Ester Hydrolase Activity In Pig And Rat Liver , Dale Alan Cooper Jan 1986

Properties Of Retinyl Ester Hydrolase Activity In Pig And Rat Liver , Dale Alan Cooper

Retrospective Theses and Dissertations

Hydrolysis of vitamin A esters by liver is important during their uptake as part of chylomicron remnants and for their mobilization from storage in vitamin A-containing globules. The regulation and properties of the enzyme thought to catalyze these reactions, retinyl ester hydrolase (REH), were studied by the use of a sensitive in vitro assay developed for this enzyme in pig and rat liver. Hydrolysis of retinyl palmitate was maximal in 3- (3-cholamidopropyl) dimethylammonio -1-propanesulfonate (CHAPS) and Triton X-100, and the production of retinol was quantified by HPLC;Regulation of hepatic REH was studied by determining the relationship between its activity ...


Effect Of The Major Histocompatibility Complex On Early Mouse Development , Sandra Oppel Gollnick Jan 1986

Effect Of The Major Histocompatibility Complex On Early Mouse Development , Sandra Oppel Gollnick

Retrospective Theses and Dissertations

The class I molecules of the murine major histocompatibility complex (MHC), the H-2 complex, are of utmost importance in the recognition of self vs. nonself, and in the regulation of the immune response. In recent years, a great deal of interest has centered on the role of the MHC in nonimmune phenomena. Among these traits are those associated with reproduction and development. We have shown that a gene, Ped (preimplantation embryo development) is associated with the H-2 complex. Ped gene expression is apparent at the first cleavage division and affects the rate of subsequent cleavages. Therefore, the Ped gene product ...