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Biological Sciences: Faculty Publications

Articles 301 - 316 of 316

Full-Text Articles in Biology

Identification Of An Escherichia Coli Genetic Locus Involved In Thermoregulation Of The Pap Operon, C. A. White-Ziegler, L. B. Blyn, B. A. Braaten, D. A. Low Jan 1990

Identification Of An Escherichia Coli Genetic Locus Involved In Thermoregulation Of The Pap Operon, C. A. White-Ziegler, L. B. Blyn, B. A. Braaten, D. A. Low

Biological Sciences: Faculty Publications

We previously showed, using a single-copy papBAp-lac fusion (previously designated papBA-lac), that pyelonephritis-associated pili (pap) pilin gene transcription is subject to both phase variation and thermoreg- ulatory control mechanisms (L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, and D. A. Low, EMBO J. 8:613-620, 1989). At 37°C, Escherichia coli strains carrying the papBAp-lac fusion displayed both Lac' and Lac- colony phenotypes. In contrast, at 23°C, colonies displayed a uniform Lac- phenotype, suggesting that pilin was not transcribed at this temperature. In this study, a strain carrying the papBAp-lac fusion was subjected to mini-TnlO (mTnlO) mutagenesis to …

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Direct Genomic Sequencing Of Bacterial Dna: The Pyruvate Kinase I Gene Of Escherichia Coli, Osamu Ohara, Robert L. Dorit, Walter Gilbert Sep 1989

Direct Genomic Sequencing Of Bacterial Dna: The Pyruvate Kinase I Gene Of Escherichia Coli, Osamu Ohara, Robert L. Dorit, Walter Gilbert

Biological Sciences: Faculty Publications

The genomic sequencing procedure is applied to the direct sequencing of uncharacterized regions of bacterial DNA by a "multiplex walking" approach. Samples of bulk Escherichia coli DNA are cut with various restriction enzymes, subjected to chemical sequencing degradations, run in a sequencing gel, and transferred to nylon membranes. When a labeled oligomer is hybridized to a membrane, a sequence ladder appears wherever the probe lies near a restriction cut. New probes, based on sequence that lies beyond other restriction sites, are then synthesized, and the membranes are reprobed to reveal new sequence. Repeated cycles of oligomer probe synthesis and subsequent …

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One-Sided Polymerase Chain Reaction: The Amplification Of Cdna, Osamu Ohara, Robert L. Dorit, Walter Gilbert Aug 1989

One-Sided Polymerase Chain Reaction: The Amplification Of Cdna, Osamu Ohara, Robert L. Dorit, Walter Gilbert

Biological Sciences: Faculty Publications

We report a rapid technique, based on the polymerase chain reaction (PCR), for the direct targeting, enhancement, and sequencing of previously uncharacterized cDNAs. This method is not limited to previously sequenced transcripts, since it requires only two adjacent or partially overlapping specific primers from only one side of the region to be amplified. These primers can be located anywhere within the message. The specific primers are used in conjunction with nonspecific primers targeted either to the poly(A)+ region of the message or to an enzymatically synthesized d( A) tail. Pairwise combinations of specific and general primers allow for the amplification …

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A Field Study Using The Polymerase Chain Reaction (Pcr) To Screen For Brugia Microfilariae In Human And Animal Blood, Janet Glover, Steven A. Williams, Susanne Szabo, David Landry, Larry A. Mcreynolds, Taniawati Supali, Felix Partono Jan 1989

A Field Study Using The Polymerase Chain Reaction (Pcr) To Screen For Brugia Microfilariae In Human And Animal Blood, Janet Glover, Steven A. Williams, Susanne Szabo, David Landry, Larry A. Mcreynolds, Taniawati Supali, Felix Partono

Biological Sciences: Faculty Publications

Blood samples from 43 humans and 14 cats with Brugia microfilariae were analyzed in a field study in Tanjung Pinang, Indonesia. The study used the polymerase chain reaction (PCR) to compare the sensitivity of radioactive and biotinylated species-specific oligonuleotide probes. The cloning char- acterization of the Hha I repeat DNA family found in filarial parasites of the genus Brugia, and the development of species-specific probes for B.malayi and B.pahangi based on these repeats has been described elsewhere (PNAS USA 83: 797-801); Mol.Biochem. Parasitol. 28: 163-170). The use of radioisotopes for labelling DNA probes is both expensive and inconvenient. To replace …

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Phase-Variation Of Pyelonephritis-Associated Pili In Escherichia Coli: Evidence For Transcriptional Regulation, L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, D. A. Low Jan 1989

Phase-Variation Of Pyelonephritis-Associated Pili In Escherichia Coli: Evidence For Transcriptional Regulation, L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, D. A. Low

Biological Sciences: Faculty Publications

The regulation of pyelonephritis-associated pill (pap) pflin gene transcription has been examined using two operons (pap-17 and pap-21) isolated from the pyelonephritogenic Escherichia coli strain C1212. DNA sequence analysis and E.coli minicell analysis were used to map two genes (papB and papl) within the pilin regulatory regions of both pap-17 and pap-21, and the protein products of these genes were identified. Pilin transcription, initiated at the papBA promoter, was monitored by constructing single copy operon fusions with lacZYA in E.coli K-12. Inocula- tion of E.coli (pap'-lac) strains onto solid M9 minimal medium containing glycerol and the Lac indicator X-gal (M9-Glycerol) …

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The Control Of Myocardial Contraction With Skeletal Fast Muscle Troponin C., A. Babu, Stylianos P. Scordilis, E. H. Sonnenblick, J. Gulati Apr 1987

The Control Of Myocardial Contraction With Skeletal Fast Muscle Troponin C., A. Babu, Stylianos P. Scordilis, E. H. Sonnenblick, J. Gulati

Biological Sciences: Faculty Publications

The present study describes experiments on the myocardial trabeculae from the right ventricle of Syrian hamsters whose troponin C (TnC) moiety was exchanged with heterologous TnC from fast skeletal muscle of the rabbit. These experiments were designed to help define the role of the various classes of Ca2+-binding sites on TnC in setting the characteristic sensitivities for activations of cardiac and skeletal muscles. Thin trabeculae were skinned and about 75% of their troponin C extracted by chemical treatment. Tension development on activations by Ca2+ and Sr2+ was found to be nearly fully blocked in such TnC extracted preparations. Troponin C …

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Cloning And Comparison Of Repeated Dna Sequences From The Human Filarial Parasite Brugia Malayi And The Animal Parasite Brugia Pahangi, Larry A. Mcreynolds, Susan M. Desimone, Steven A. Williams Feb 1986

Cloning And Comparison Of Repeated Dna Sequences From The Human Filarial Parasite Brugia Malayi And The Animal Parasite Brugia Pahangi, Larry A. Mcreynolds, Susan M. Desimone, Steven A. Williams

Biological Sciences: Faculty Publications

No abstract provided.

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Metatherian Reproduction: Transitional Or Transcending?, Virginia Hayssen, R. C. Lacy, P. J. Parker Jan 1985

Metatherian Reproduction: Transitional Or Transcending?, Virginia Hayssen, R. C. Lacy, P. J. Parker

Biological Sciences: Faculty Publications

The major difference between metatherian and eutherian reproductive patterns is the relative apportionment of maternal resources to gestation versus lactation, not the total temporal and energetic investment in each reproductive attempt. Gestation accounts for an average of 12% of the time from conception to weaning in marsupials; in placental mammals it accounts for 56% of this period of development. Parental investment at birth is less in marsupials (litter weight averages 0.09% of female body mass) than in eutherians (average 15.5%), but total maternal effort is comparable in the two groups, since the litter weight at weaning is similar for metatherians …

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Cloning The Gene For The Malolactic Fermentation Of Wine From Lactobacillus Delbrueckii In Escherichia Coli And Yeasts., Steven A. Williams, Robert A. Hodges, Terry L. Strike, Richard Snow, Ralph E. Kunkee Feb 1984

Cloning The Gene For The Malolactic Fermentation Of Wine From Lactobacillus Delbrueckii In Escherichia Coli And Yeasts., Steven A. Williams, Robert A. Hodges, Terry L. Strike, Richard Snow, Ralph E. Kunkee

Biological Sciences: Faculty Publications

No abstract provided.

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Macrophages Contain At Least Two Myosins, John A. Trotter, Stylianos P. Scordilis, Sarkis S. Margossian May 1983

Macrophages Contain At Least Two Myosins, John A. Trotter, Stylianos P. Scordilis, Sarkis S. Margossian

Biological Sciences: Faculty Publications

A number of motile functions of macrophages are thought to be mediated by myosin. We have observed that myosin from rabbit alveolar macrophages is heterogeneous with respect to its 20 kDa light chain: two species of 20 kDa light chain are identified by one-dimensional and two-dimensional polyacrylamide gel electrophoresis, in a ratio of 2:1. Native myosin, analyzed on non-denaturing gels, is also composed of two species, in a ratio of 2:1. These results indicate that macrophages contain at least two different myosins, which might have different physiological functions.

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Changes In Myosin And Myosin Light Chain Kinase During Myogenesis, Stylianos P. Scordilis, J. Maurice Miles, Robert S. Adelstein, B. William Uhlendorf, Sigfrido Scarpa, Giulio L. Cantoni Jan 1981

Changes In Myosin And Myosin Light Chain Kinase During Myogenesis, Stylianos P. Scordilis, J. Maurice Miles, Robert S. Adelstein, B. William Uhlendorf, Sigfrido Scarpa, Giulio L. Cantoni

Biological Sciences: Faculty Publications

Myosins and myosin light chain kinases have been isolated from a cloned line of myoblasts (L5/A10) as this cell line undergoes differentiation toward adult muscle. At least three myosin isozymes were obtained during this developmental process. Initially a nonmuscle type of myosin was found in the myoblasts. The molecular weights of the myoblast light chains were 20 000 and 15 000. Myosin isolated from early myotubes had light chains with molecular weights of 20 000 and 19 500. Myosin isolated from myotubes which contained sarcomeres had light chains with molecular weights of 23 000, 18 500, and 16000. This last …

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A Comparative Study Of The Myosin Light Chain Kinases From Myoblast And Muscle Sources. Studies On The Kinases From Proliferative Rat Myoblasts In Culture, Rat Thigh Muscle, And Rabbit Skeletal Muscle, S. P. Scordilis, R. S. Adelstein Dec 1978

A Comparative Study Of The Myosin Light Chain Kinases From Myoblast And Muscle Sources. Studies On The Kinases From Proliferative Rat Myoblasts In Culture, Rat Thigh Muscle, And Rabbit Skeletal Muscle, S. P. Scordilis, R. S. Adelstein

Biological Sciences: Faculty Publications

Myosin light chain kinases have been isolated from rat thigh and rabbit skeletal muscle and cultured rat myoblasts. From these preparations, two types of kinases can be distinguished: calcium-dependent and calcium-independent. Both types of kinases can phosphorylate isolated P-light chains of myosin from several sources (skeletal muscle, cardiac muscle, and platelet). Data are shown which support the phosphorylation of the same site on the non-muscle P-light chains by both types of kinases. The rates of these reactions are, however, different for the two types of kinases. Kinetic analysis of the myoblast kinase show differing affinities for various P-light chains (non-muscle …

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Membrane Potentials And Resistances Of Giant Mitochondria: Metabolic Dependence And The Effects Of Valinomycin, Bruce L. Maloff, Stylianos P. Scordilis, Christopher Reynolds, Henry Tedeschi Jul 1978

Membrane Potentials And Resistances Of Giant Mitochondria: Metabolic Dependence And The Effects Of Valinomycin, Bruce L. Maloff, Stylianos P. Scordilis, Christopher Reynolds, Henry Tedeschi

Biological Sciences: Faculty Publications

The membrane potentials and resistances of giant mitochondria from mice fed cuprizone have been studied. They were found to correspond approx. 10-20 mV, positive inside, and 2 M omega, respectively. These properties were found to be independent of the metabolic state. The microelectrodes were in the inner mitochondrial space since (a) the potentials in the presence of valinomycin depended on the K+ concentration of the medium and magnitude of the K+ diffusion potentials was consistent with the presence of a high internal concentration of K+, (b) almost identical results were obtained with mitochondria from which the external membrane had been …

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Assays Of The Metabolic Viability Of Single Giant Mitochondria. Experiments With Intact And Impaled Mitochondria, B. L. Maloff, S. P. Scordilis, H. Tedeschi Jan 1978

Assays Of The Metabolic Viability Of Single Giant Mitochondria. Experiments With Intact And Impaled Mitochondria, B. L. Maloff, S. P. Scordilis, H. Tedeschi

Biological Sciences: Faculty Publications

Single giant mitochondria isolated from mice fed cuprizone were assayed for their metabolic viability. Two tests were devised. One test optically detected the accumulation of calcium phosphate within the mitochondria under massive loading conditions (including the presence of succinate and ATP). The accumulation corresponds to a test of energy coupling from either electron transport or the hydrolysis of ATP since it is blocked by either antimycin A or oligomycin. The other assay tested for the production of ATP from ADP and Pi, using myofibrils. Myofibrils prepared from glycerinated rabbit psoas muscle contract only in the presence of ATP and not …

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Characterization Of The Myosin-Phosphorylating System In Normal Murine Astrocytes And Derivative Sv40 Wild-Type And A-Mutant Transformants, S. P. Scordilis, J. L. Anderson, R. Pollack, R. S. Adelstein Jan 1977

Characterization Of The Myosin-Phosphorylating System In Normal Murine Astrocytes And Derivative Sv40 Wild-Type And A-Mutant Transformants, S. P. Scordilis, J. L. Anderson, R. Pollack, R. S. Adelstein

Biological Sciences: Faculty Publications

Myosin and myosin light-chain kinase have been isolated and characterized from small quantities of normal and SV40-transformed, murine astrocytic neuroglial cells in culture and from intact normal mouse brain. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the astrocyte myosins revealed a heavy chain of 200,000 daltons and two light chains of 20,000 and 15,000 daltons. These myosins are similar to other cytoplasmic myosins. The astrocyte 20,000-dalton light chain can be phosphorylated by an endogenous myosin light- chain kinase which has properties similar to those of the myosin light-chain kinase found in human platelets. No differences were detected in either the …

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Donnan Potential Of Rabbit Skeletal Muscle Myofibrils I: Electrofluorochromometric Detection Of Potential, S. P. Scordilis, H. Tedeschi, C. Edwards Jan 1975

Donnan Potential Of Rabbit Skeletal Muscle Myofibrils I: Electrofluorochromometric Detection Of Potential, S. P. Scordilis, H. Tedeschi, C. Edwards

Biological Sciences: Faculty Publications

The fluorescence of the dye CC 6 [(3 hexyl 2 (3 hexyl 2 benzoxazolinylidene) 1 propenyl) benzoxazolium iodide] was shown to indicate Donnan potentials in rabbits skeletal muscle myofibrils. These results are in aggreement with previously published work in which the potentials were measured with microelectrodes on glycerol extracted muscle fibers. The magnitude of the Donnan potential of the myofibrils was shown to be dependent on the state (rigor or relaxed) of the system.

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