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Articles 781 - 810 of 1010

Full-Text Articles in Biology

Effect Of Hindlimb Unweighting On Single Soleus Fiber Maximal Shortening Velocity And Atpase Activity, Kerry S. Mcdonald, Robert H. Fitts Jun 1993

Effect Of Hindlimb Unweighting On Single Soleus Fiber Maximal Shortening Velocity And Atpase Activity, Kerry S. Mcdonald, Robert H. Fitts

Biological Sciences Faculty Research and Publications

This study characterizes the time course of change in single soleus muscle fiber size and function elicited by hindlimb unweighting (HU) and analyzes the extent to which varying durations of HU altered maximal velocity of shortening (Vo), myofibrillar adenosinetriphosphatase (ATPase), and relative content of slow and fast myosin in individual soleus fibers. After 1, 2, or 3 wk of HU, soleus muscle bundles were prepared and stored in skinning solution at -20 degrees C. Single fibers were isolated and mounted between a motor arm and a transducer, and fiber force, Vo, and ATPase activity were …

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Smooth Muscle Myosin Heavy Chains Combine To Form Three Native Myosin Isoforms, Allen E. Tsao, Thomas J. Eddinger May 1993

Smooth Muscle Myosin Heavy Chains Combine To Form Three Native Myosin Isoforms, Allen E. Tsao, Thomas J. Eddinger

Biological Sciences Faculty Research and Publications

Two smooth muscle myosin heavy chains (MHC; SM1 and SM2) of approximately 204 and 200 kDa exist in smooth muscle cells and can be visualized on reducing sodium dodecyl sulfate (SDS)-polyacrylamide gels. Chymotryptic digestion of the native myosin molecule results in two fragments: heavy meromyosin (HMM) and light meromyosin (LMM). LMM is the alpha-helical coiled-coil carboxy terminal half of the molecule containing the difference peptide between SM1 and SM2. Electrophoresis of the LMM fragments on a reducing SDS-polyacrylamide gel resolves two subunits from the two MHC [LM1 from SM1 (approximately 100 kDa) and LM2 from SM2 (approximately 95 kDa), where …

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Fatigability And Blood Flow In The Rat Gastrocnemius-Plantaris-Soleus After Hindlimb Suspension, Kerry S. Mcdonald, M. D. Delp, Robert H. Fitts Sep 1992

Fatigability And Blood Flow In The Rat Gastrocnemius-Plantaris-Soleus After Hindlimb Suspension, Kerry S. Mcdonald, M. D. Delp, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to test the hypothesis that hindlimb suspension increases the fatigability of the soleus during intense contractile activity and determine whether the increased fatigue is associated with a reduced muscle blood flow. Cage-control (C) and 15-day hindlimb-suspended (HS) rats were anesthetized, and either the gastrocnemius-plantaris-soleus (G-P-S) muscle group or the soleus was stimulated (100 Hz, 100-ms trains at 120/min) for 10 min in situ. In the G-P-S preparation, blood flow was measured with radiolabeled microspheres before and at 2 and 10 min of contractile activity. The G-P-S fatigued markedly at this stimulation frequency, and the …

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Dissection Of Nodule Development By Supplementation Of Rhizobium Leguminosarum Biovar Phaseoli Purine Auxotrophs With 4-Aminoimidazole-5-Carboxamide Riboside, Jeffrey D. Newman, Bruce W. Schultz, K. Dale Noel Jun 1992

Dissection Of Nodule Development By Supplementation Of Rhizobium Leguminosarum Biovar Phaseoli Purine Auxotrophs With 4-Aminoimidazole-5-Carboxamide Riboside, Jeffrey D. Newman, Bruce W. Schultz, K. Dale Noel

Biological Sciences Faculty Research and Publications

Purine auxotrophs of Rhizobium leguminosarum biovar phaseoli CFN42 elicit uninfected pseudonodules on bean (Phaseolus vulgaris L.). Addition of 4-aminoimidazole-5-carboxamide (AICA) riboside to the root medium during incubation of the plant with these mutants leads to enhanced nodule development, although nitrogenase activity is not detected. Nodules elicited in this manner had infection threads and anatomical features characteristic of normal nodules, such as peripheral vasculature rather than the central vasculature of the pseudonodules that were elicited without AICA riboside supplementation. Although 105 to 106 bacteria could be recovered from these nodules after full development, bacteria were not observed in …

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Effect Of Hindlimb Unweighting On Tissue Blood Flow In The Rat, Kerry S. Mcdonald, M. D. Delp, Robert H. Fitts Jun 1992

Effect Of Hindlimb Unweighting On Tissue Blood Flow In The Rat, Kerry S. Mcdonald, M. D. Delp, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to characterize the distribution of blood flow in the rat during hindlimb unweighting (HU) and post-HU standing and exercise and examine whether the previously reported (Witzmann et al., J. Appl. Physiol. 54: 1242–1248, 1983) elevation in anaerobic metabolism observed with contractile activity in the atrophied soleus muscle was caused by a reduced hindlimb blood flow. After either 15 days of HU or cage control, blood flow was measured with radioactive microspheres during unweighting, normal standing, and running on a treadmill (15 m/min). In another group of control and experimental animals, blood flow was measured …

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Heterogeneous Nuclear Ribonucleoprotein A1 Catalyzes Rna.Rna Annealing, Stephen Munroe, Xiaofan Dong Feb 1992

Heterogeneous Nuclear Ribonucleoprotein A1 Catalyzes Rna.Rna Annealing, Stephen Munroe, Xiaofan Dong

Biological Sciences Faculty Research and Publications

Within the nucleus, pre-mRNA molecules are complexed with a set of proteins to form heterogeneous nuclear ribonucleoprotein complexes. A1, an abundant RNA binding protein present in these complexes, has been shown to bind selectively to single-stranded RNAs and destabilize base-pairing interactions. In this study.A1 is shown to promote the rate of annealing of complementary RNA strands greater than 300-fold under a wide range of salt concentration and temperature. Maximal annealing is observed under saturating or near saturating concentrations of protein, but annealing decreases sharply at both higher and lower concentrations of A1. Kinetic analysis shows that the rate of annealing …

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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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Boll Weevil Testis-Specific Cdna, Patrick M. Trewitt, Larry J. Heilmann, A. Krishna Kumaran Jun 1990

Boll Weevil Testis-Specific Cdna, Patrick M. Trewitt, Larry J. Heilmann, A. Krishna Kumaran

Biological Sciences Faculty Research and Publications

No abstract provided.

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Transcriptional Regulation Of Gene Expression In Tetrahymena Thermophila, Laurie A. Stargell, Kathleen M. Karrer, Martin A. Gorovsky Jan 1990

Transcriptional Regulation Of Gene Expression In Tetrahymena Thermophila, Laurie A. Stargell, Kathleen M. Karrer, Martin A. Gorovsky

Biological Sciences Faculty Research and Publications

The only well-characterized study of gene expression in Tetrahymena thermophila (1) demonstrates that the temperature dependent expression of the Ser H3 gene is regulated at the level of mRNA stability. A run-on transcription assay was developed to determine if regulation of RNA stability was a major mechanism regulating gene expression in Tetrahymena or if transcriptional regulation dominates. The relative transcriptional activities of 14 Tetrahymena genes were determined in different physiological/developmental states (growing, starved and conjugating) in which many of the genes showed striking differences in RNA abundance. In every case except Ser H3, changes in transcription accompanied changes in RNA …

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The Voltage Sensor Of Excitation-Contraction Coupling In Skeletal Muscle. Ion Dependence And Selectivity, Gonzalo Pizarro, Robert H. Fitts, Ismael Uribe, Eduardo Rios Sep 1989

The Voltage Sensor Of Excitation-Contraction Coupling In Skeletal Muscle. Ion Dependence And Selectivity, Gonzalo Pizarro, Robert H. Fitts, Ismael Uribe, Eduardo Rios

Biological Sciences Faculty Research and Publications

Manifestations of excitation-contraction (EC) coupling of skeletal muscle were studied in the presence of metal ions of the alkaline and alkaline-earth groups in the extracellular medium. Single cut fibers of frog skeletal muscle were voltage clamped in a double Vaseline gap apparatus, and intramembrane charge movement and myoplasmic Ca2+ transients were simultaneously measured. In metal-free extracellular media both charge movement of the charge 1 type and Ca transients were suppressed. Under metal-free conditions the nonlinear charge distribution was the same in depolarized (holding potential of 0 mV) and normally polarized fibers (holding potentials between -80 and -90 mV). The manifestations …

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Identification Of Excitatory Interneurons Contributing To Generation Of Locomotion In Lamprey: Structure, Pharmacology, And Function, James T. Buchanan, Stan Grillner, Staffan Cullheim, Mårten Risling Jul 1989

Identification Of Excitatory Interneurons Contributing To Generation Of Locomotion In Lamprey: Structure, Pharmacology, And Function, James T. Buchanan, Stan Grillner, Staffan Cullheim, Mårten Risling

Biological Sciences Faculty Research and Publications

1. In the in vitro preparation of the lamprey spinal cord, paired intracellular recordings of membrane potential were used to identify interneurons producing excitatory postsynaptic potentials (EPSPs) on myotomal motoneurons. 2. Seventy-nine interneurons (8.4% of all neuron-motoneuron pairs tested) elicited unitary EPSPs that followed one-for-one at short, constant latencies and were therefore considered monosynaptic according to conventional criteria. Evidence was obtained for selectivity and divergence of excitatory interneuron (EIN) outputs and for convergence of EIN input to motoneurons. 3. The neurotransmitter released by EINs may be an excitatory amino acid such as glutamate, because the EPSPs were depressed by antagonists …

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Molecular Analysis Of N6-Methyladenine Patterns In Tetrahymena Thermophila Nuclear Dna, Elizabeth E. Capowski, John M. Wells, Gail Singer Harrison, Kathleen M. Karrer Jun 1989

Molecular Analysis Of N6-Methyladenine Patterns In Tetrahymena Thermophila Nuclear Dna, Elizabeth E. Capowski, John M. Wells, Gail Singer Harrison, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

We have cloned two DNA fragments containing 5'-GATC-3' sites at which the adenine is methylated in the macronucleus of the ciliate Tetrahymena thermophila. Using these cloned fragments as molecular probes, we analyzed the maintenance of methylation patterns at two partially and two uniformly methylated sites. Our results suggest that a semiconservative copying model for maintenance of methylation is not sufficient to account for the methylation patterns we found during somatic growth of Tetrahymena. Although we detected hemimethylated molecules in macronuclear DNA, they were present in both replicating and nonreplicating DNA. In addition, we observed that a complex methylation …

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Contractile Function Of Single Muscle Fibers After Hindlimb Suspension, P. R. Gardetto, Jane Marie Schluter, Robert H. Fitts Jun 1989

Contractile Function Of Single Muscle Fibers After Hindlimb Suspension, P. R. Gardetto, Jane Marie Schluter, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this investigation was to determine how muscle atrophy produced by the hindlimb suspension (HS) model alters the contractile function of slow- and fast-twitch single muscle fibers. After 2 wk of HS, small bundles of fibers were isolated from the soleus and the deep and superficial regions of the lateral and medial heads of the gastrocnemius, respectively. The bundles were placed in skinning solution and stored at -20ºC until studied. Single fibers were isolated and suspended between a motor arm and force transducer, the functional properties were studied, and subsequently the fiber type was established by myosin heavy …

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Effects Of 5-Hydroxytryptamine On The Afterhyperpolarization, Spike Frequency Regulation, And Oscillatory Membrane Properties In Lamprey Spinal Cord Neurons, P. Wallén, James T. Buchanan, Stan Grillner, R. H. Hill, J. Christenson, T. Hökfelt Apr 1989

Effects Of 5-Hydroxytryptamine On The Afterhyperpolarization, Spike Frequency Regulation, And Oscillatory Membrane Properties In Lamprey Spinal Cord Neurons, P. Wallén, James T. Buchanan, Stan Grillner, R. H. Hill, J. Christenson, T. Hökfelt

Biological Sciences Faculty Research and Publications

1. Local application of 5-hydroxytryptamine (5-HT) in the area in which a dense 5-HT plexus is located in the lamprey spinal cord leads to a marked depression of the late phase of the afterhyperpolarization (AHP) following the action potential. This effect was observed in motoneurons, premotor interneurons, and giant interneurons, whereas no effect was observed in the sensory dorsal cells and edge cells. 2. The late 5-HT sensitive phase of the AHP was increased in amplitude when calcium entry was enhanced during the prolongation of action potentials caused by tetraethylammonium (TEA). Conversely, a blockade of Ca2+ entry by manganese reduced …

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Methylation Of Replicating And Nonreplicating Dna In The Ciliate Tetrahymena Thermophila, Gail Singer Harrison, Kathleen M. Karrer Feb 1989

Methylation Of Replicating And Nonreplicating Dna In The Ciliate Tetrahymena Thermophila, Gail Singer Harrison, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

Methylation of adenine in replicating and nonreplicating DNA of the ciliate Tetrahymena thermophila was examined. In growing cells, 87% of the methylation occurred on the newly replicated daughter strand, but methylation was also detectable on the parental strand. Methylation of nonreplicating DNA from starved cells was demonstrated.

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Effect Of Swim Exercise Training On Human Muscle Fiber Function, Robert H. Fitts, D. L. Costill, P. R. Gardetto Jan 1989

Effect Of Swim Exercise Training On Human Muscle Fiber Function, Robert H. Fitts, D. L. Costill, P. R. Gardetto

Biological Sciences Faculty Research and Publications

This study examined the effect of a typical collegiate swim-training program and an intensified 10-day training period on the peak tension (Po), negative log molar Ca2+ concentration (pCa)-force, and maximal shortening speed (Vmax) of the slow-twitch type I and fast-twitch type II fibers of the deltoid muscle. Over a 10-wk period, the swimmers averaged 4,266 ± 264 m/day swimming intermittent bouts of front crawl, kicking, or pulling. The training program induced an almost twofold increase in the mitochondrial marker enzyme citrate synthase. Po of the single fibers was not altered by either the training …

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Transformation Of Tetrahymena Thermophila With Hypermethylated Rrna Genes, Kathleen M. Karrer, Meng-Chao Yao Apr 1988

Transformation Of Tetrahymena Thermophila With Hypermethylated Rrna Genes, Kathleen M. Karrer, Meng-Chao Yao

Biological Sciences Faculty Research and Publications

The extrachromosomal rRNA genes (rDNA) of Tetrahymena thermophila contain 0.4% N6-methyladenine. C3 strain rDNA was isolated, hypermethylated in vitro, and microinjected into B strain host cells. Clonal cell lines were established, and transformants were selected on the basis of resistance to paromomycin, conferred by the injected rDNA. The effects of methylation by three enzymes which methylate the sequence 5'-NAT-3', the dam, EcoRI, and ClaI methylases, were tested. Hypermethylation of the injected rDNA had no effect on transformation efficiency relative to mock-methylated controls. The injected C3 strain rDNA efficiently replaced host rDNA as the major constituent of the population of rDNA …

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Characterization Of The Lipopolysaccharide From A Rhizobium Phaseoli Mutant That Is Defective In Infection Thread Development, Russell W. Carlson, Stanislaw Kalembasa, Debra A. Turowski, Pappi Pachori, K. Dale Noel Nov 1987

Characterization Of The Lipopolysaccharide From A Rhizobium Phaseoli Mutant That Is Defective In Infection Thread Development, Russell W. Carlson, Stanislaw Kalembasa, Debra A. Turowski, Pappi Pachori, K. Dale Noel

Biological Sciences Faculty Research and Publications

The lipopolysaccharide (LPS) from a Rhizobium phaseoli mutant, CE109, was isolated and compared with that of its wild-type parent, CE3. A previous report has shown that the mutant is defective in infection thread development, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that it has an altered LPS (K. D. Noel, K. A. VandenBosch, and B. Kulpaca, J. Bacteriol. 168:1392-1462, 1986). Mild acid hydrolysis of the CE3 LPS released a polysaccharide and an oligosaccharide, PS1 and PS2, respectively. Mild acid hydrolysis of CE109 LPS released only an oligosaccharide. Chemical and immunochemical analyses showed that CE3-PS1 is the antigenic O chain of …

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Fatigue From High- And Low-Frequency Muscle Stimulation: Contractile And Biochemical Alterations, Joseph Mark Metzger, Robert H. Fitts May 1987

Fatigue From High- And Low-Frequency Muscle Stimulation: Contractile And Biochemical Alterations, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

This study examined the effect of high- (75 Hz, 1 min) and low- (5 Hz, 1.5 min) frequency stimulation on contractile and biochemical properties of the diaphragm. Tension was reduced to 21 ± 1 and 54 ± 2% (SE) of the initial value after high- and low-frequency stimulation, respectively. After 0, 0.25, 1, and 2 min of recovery from high-frequency stimulation, 5 Hz elicited more force (expressed as % of initial tension) than 75-Hz stimulation. Time 0 recovery values were 21 ± 1 and 78 ± 6% of the initial force for 75- and 5-Hz stimulation, respectively. By 1 min …

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Role Of Intracellular Ph In Muscle Fatigue, Joseph Mark Metzger, Robert H. Fitts Apr 1987

Role Of Intracellular Ph In Muscle Fatigue, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

Intracellular pH of in vitro diaphragm preparations was determined following low- (5 Hz, 1.5 min) and high- (75 Hz, 1 min) frequency stimulation, using glass microelectrodes of the liquid membrane type (pHm). Results were compared with values obtained by the standard homogenate technique (pHh). High- and low-frequency stimulation reduced peak tetanic tension to 21 ± 1 (SE) and 71 ± 2% of initial values, respectively. Peak tetanic tension returned to resting values after 10- to 15-min recovery from high- or low-frequency stimulation. Resting pHm was 7.063 ± 0.011 (n = 72), and after fatiguing …

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Mutations In Rhizobium Phaseoli That Lead To Arrested Development Of Infection Threads, K. Dale Noel, Kathryn A. Vandenbosch, Bruce Kulpaca Dec 1986

Mutations In Rhizobium Phaseoli That Lead To Arrested Development Of Infection Threads, K. Dale Noel, Kathryn A. Vandenbosch, Bruce Kulpaca

Biological Sciences Faculty Research and Publications

Two Rhizobium phaseoli mutants, isolated previously by Tn5 mutagenesis, elicited infection threads which ceased development prematurely, usually within root hairs. These infection threads were wide, globular, and otherwise altered in morphology, compared with normal infection threads. Anatomy and division of the root cortical cells during initial stages of nodule morphogenesis appeared normal. However, later nodule differentiation deviated considerably from normal development, and release of bacteria from infection threads was not observed. In tryptone-yeast extract medium the mutants sedimented during growth in shaken cultures and formed rough colonies on agar. Electrophoresis of washed cultures solubilized in dodecyl sulfate revealed that the …

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A Family Of Dna Sequences Is Reproducibly Rearranged In The Somatic Nucleus Of Tetrahymena, Bernice A. Allitto, Kathleen M. Karrer Oct 1986

A Family Of Dna Sequences Is Reproducibly Rearranged In The Somatic Nucleus Of Tetrahymena, Bernice A. Allitto, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

A small family of DNA sequences Is rearranged during the development of the somatic nucleus in Tetrahymena. The family is defined by 266 bp of highly conserved sequence which restriction mapping, hybridization and sequence analysis have shown is shared by a cloned micronuclear fragment and three sequences which constitute the macronuclear family. Genomic Southern hybridization experiments indicate there are five members of the family in micronuclear DNA. All of the family members are present in whole genome homozygotes and are therefore nonallellic. The three macronuclear sequences are all present in clonal cell lines and are reproducibly generated in every …

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Site-Specific Methylation Of Adenine In The Nuclear Genome Of A Eucaryote, Tetrahymena Thermophila, Gail Singer Harrison, R. Craig Findly, Kathleen M. Karrer Jul 1986

Site-Specific Methylation Of Adenine In The Nuclear Genome Of A Eucaryote, Tetrahymena Thermophila, Gail Singer Harrison, R. Craig Findly, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

DNA in the polyploid macronucleus of the ciliated protozoan Tetrahymena thermophila contains the modified base N6-methyladenine. We identified two GATC sites which are methylated in most or all of the 45 copies of the macronuclear genome. One site is 2 kilobases 5' to the histone H4-I gene, and the other is 5 kilobases 3' to the 73-kilodalton heat shock protein gene. These sites are de novo methylated between 10 and 16 h after initiation of conjugation, during macronuclear anlage development. The methylation states of these two GATC sites and four other unmethylated GATC sites do not change in the DNA …

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Models Of Disuse: A Comparison Of Hindlimb Suspension And Immobilization, Robert H. Fitts, Joseph Mark Metzger, Denise A. Riley, B. R. Unsworth Jun 1986

Models Of Disuse: A Comparison Of Hindlimb Suspension And Immobilization, Robert H. Fitts, Joseph Mark Metzger, Denise A. Riley, B. R. Unsworth

Biological Sciences Faculty Research and Publications

The effects of 1 and 2 wk of hindlimb suspension (HS) on rat skeletal muscle function were determined and the results compared with those obtained previously with hindlimb immobilization (HI). Both models of disuse (HS and HI) primarily affected slow-twitch muscle. Each decreased the isometric twitch duration in the slow-twitch soleus; however, the HS-mediated effect was entirely a result of a shortened contraction time (CT), whereas HI reduced one-half relaxation time (½RT) as well as CT. Soleus muscle mass and peak tetanic tension (P0) declined with disuse. The HS effect on muscle mass and P0 was variable, …

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Effect Of High-Intensity Exercise Training On Functional Capacity Of Limb Skeletal Muscle, John Patrick Troup, Joseph Mark Metzger, Robert H. Fitts May 1986

Effect Of High-Intensity Exercise Training On Functional Capacity Of Limb Skeletal Muscle, John Patrick Troup, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to determine whether a program of regular sprint exercise training alters the functional properties or protects against the development of fatigue in fast- and slow-twitch rat skeletal muscle. The training program consisted of 6 sprints of 4.5-min duration at 40 m/min and 15% slope with 2.5-min rest intervals, performed 5 days/wk for 6 wk. The exercise program significantly increased (P-1·min-1) in the predominantly type I soleus (SOL) from 28 ± 2 to 44 ± 2; the type IIb superficial region of the vastus lateralis (SVL) from 10 ± 1 to 16 ± …

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Contractile And Biochemical Properties Of Diaphragm: Effects Of Exercise Training And Fatigue, Joseph Mark Metzger, Robert H. Fitts May 1986

Contractile And Biochemical Properties Of Diaphragm: Effects Of Exercise Training And Fatigue, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The effect of high-intensity trained (6 X 4.5 min at 40 m/min, 15% grade, 2.5-min rest between bouts, 5 days/wk, for 6 wk) on contractile, biochemical, and fatigue properties of the rat diaphragm were examined. The exercise program produced significant elevations in the mitochondrial marker enzyme citrate synthase (µmol·X·g-1·X min-1) in the soleus (SOL) (27.2 ± 1.5 vs. 46.7 ± 2.4; mean ± SE), deep vastus lateralis (DVL) (40.8 ± 2.6 vs. 58.3 ± 2.8), and superficial vastus lateralis (SVL) (8.5 +/- 0.6 vs. 11.4 +/- 0.7). No significant differences were observed in the crural (CRU) …

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Fiber Number And Type Composition In Extensor Digitorum Longus, Soleus, And Diaphragm Muscles With Aging In Fisher 344 Rats, Thomas J. Eddinger, Richard L. Moss, Robert G. Cassens Oct 1985

Fiber Number And Type Composition In Extensor Digitorum Longus, Soleus, And Diaphragm Muscles With Aging In Fisher 344 Rats, Thomas J. Eddinger, Richard L. Moss, Robert G. Cassens

Biological Sciences Faculty Research and Publications

Histochemical (M-ATPase) fiber typing was done on extensor digitorum longus, (EDL), soleus (SOL), and diaphragm (DIA) muscles of barrier-reared Fisher 344 rats obtained at four different ages (3, 9, 28, and 30 months) from the colonies of the National Institute of Aging. In the EDL there are no differences in the percent of type I fibers among the four age groups. The percent of type IIa and IIb fibers also showed no difference between the 3 and 30 month age groups. There was no apparent trend for an increase or decrease in the percent of type IIa or IIb fibers …

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Recovery In Skeletal Muscle Contractile Function After Prolonged Hindlimb Immobilization, Robert H. Fitts, C. J. Brimmer Sep 1985

Recovery In Skeletal Muscle Contractile Function After Prolonged Hindlimb Immobilization, Robert H. Fitts, C. J. Brimmer

Biological Sciences Faculty Research and Publications

Contractile properties of slow-twitch soleus (SOL), fast-twitch extensor digitorum longus (EDL), and fast-twitch superficial region of the vastus lateralis were determined in vitro (22ºC) in rats remobilized after prolonged (3 mo) hindlimb immobilization (IM). For all muscles the muscle-to-body weight ratio was significantly depressed by IM, and the ratios failed to completely recover even after 90 days. The contractile properties of the fast-twitch muscles were less affected by IM than the slow-twitch SOL. The IM shortened the SOL isometric twitch duration due to a reduced contraction and half-relaxation time. These parameters returned to control levels by the 14th day of …

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Nodule Initiation Elicited By Noninfective Mutants Of Rhizobium Phaseoli, Kathryn A. Vandenbosch, K. Dale Noel, Yasuko Kaneko, Eldon H. Newcomb Jun 1985

Nodule Initiation Elicited By Noninfective Mutants Of Rhizobium Phaseoli, Kathryn A. Vandenbosch, K. Dale Noel, Yasuko Kaneko, Eldon H. Newcomb

Biological Sciences Faculty Research and Publications

Rhizobium phaseoli CE106, CE110, and CE115, originally derived by transposon mutagenesis (Noel et al., J. Bacteriol. 158:149-155, 1984), induced the formation of uninfected root nodule-like swellings on bean (Phaseolus vulgaris). Bacteria densely colonized the root surface, and root hair curling and initiation of root cortical-cell divisions occurred normally in mutant-inoculated seedlings, although no infection threads formed. The nodules were ineffective, lacked leghemoglobin, and were anatomically distinct from normal nodules. Ultrastructural specialization for ureide synthesis, characteristic of legumes that form determinate nodules, was absent. Colony morphology of the mutant strains on agar plates was less mucoid than that of …

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Histochemical And Physiological Characteristics Of The Rat Diaphragm, Joseph Mark Metzger, K. B. Scheidt, Robert H. Fitts Apr 1985

Histochemical And Physiological Characteristics Of The Rat Diaphragm, Joseph Mark Metzger, K. B. Scheidt, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The histochemical and contractile characteristics of the adult rat diaphragm were determined. Based on enzyme histochemistry, the rat diaphragm contained 40% type I, 27% type IIa, and 34% type IIb fibers. There were significantly more type I fibers in the ventral costal (VEN) compared with the crural (CRU) region of the muscle and a slightly higher percentage of type I's on the thoracic relative to the abdominal surface. The contractile properties and the effect of temperature (Q10) were similar in the VEN and CRU regions. Increasing temperature produced higher isometric peak tetanic tension, whereas twitch tension, contraction, and …

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