Life Sciences Commons^™

Rhoa Kinase And Protein Kinase C Participate In Regulation Of Rabbit Stomach Fundus Smooth Muscle Contraction, Paul H. Ratz, Joel T. Meehl, Thomas Eddinger

Biological Sciences Faculty Research and Publications

1. The degree to which the RhoA kinase (ROK) blockers, Y-27632 (1 µM) and HA-1077 (10 µM), and the PKC blocker, GF-109203X (1 µM), reduced force produced by carbachol, a muscarinic receptor agonist, and phenylephrine, an α-adrenoceptor agonist, was examined in rabbit stomach fundus smooth muscle.

2. When examining the effect on cumulative carbachol concentration-response curves (CRCs), ROK and PKC blockers shifted the potency (~EC50) to the right but did not reduce the maximum response.

3. In a single-dose carbachol protocol using moderate (~EC50) and maximum carbachol concentrations, Y-27632 and HA-1077 reduced peak force, but GF-109203X had no effect. By …

Asi1, A Gene Encoding A Novel Leucine Zipper Protein, Is Induced During Development Of The Macronucleus In Tetrahymena, Rupa A. Udani, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

Sexual reproduction in the ciliate Tetrahymena follows a complex developmental program involving the sequential regulation of dozens of genes. Genes that are up-regulated during post-zygotic development in Tetrahymena were isolated by subtractive hybridization. Anlagen stage induced gene 1 (ASI1) encodes a 2.8 kb transcript that contains a single intron and is induced during macronuclear development. ASI1 is a single copy gene in both the micronucleus and the macronucleus. It encodes a 95 kDa conceptual protein with a leucine zipper near the amino terminus

Insertion Of Proteins Into The Inner Membrane Of Mitochondria: The Role Of The Oxa1 Complex, Rosemary A. Stuart

Biological Sciences Faculty Research and Publications

The inner mitochondrial membrane harbors a large number of proteins that display a wide range of topological arrangements. The majority of these proteins are encoded in the cell's nucleus, but a few polytopic proteins, all subunits of respiratory chain complexes are encoded by the mitochondrial genome. A number of distinct sorting mechanisms exist to direct these proteins into the mitochondrial inner membrane. One of these pathways involves the export of proteins from the matrix into the inner membrane and is used by both proteins synthesized within the mitochondria, as well as by a subset of nuclear encoded proteins. Prior to …

Herbivore And Pathogen Damage On Grassland And Woodland Plants: A Test Of The Herbivore Uncertainty Principle, Stefan A. Schnitzer, Peter B. Reich, Belle Bergner, Walter P. Carson

Biological Sciences Faculty Research and Publications

Researchers can alter the behaviour and ecology of their study organisms by conducting such seemingly benign activities as non‐destructive measurements and observations. In plant communities, researcher visitation and measurement of plants may increase herbivore damage in some plant species while decreasing it in others. Simply measuring plants could change their competitive ability by altering the amount of herbivore damage that they suffer. Currently, however, there is only limited empirical evidence to support this `herbivore uncertainty principle' (HUP). We tested the HUP by quantifying the amount of herbivore and pathogen damage in 13 plant species (> 1400 individuals) at four different …

A Novel Family Of Mobile Genetic Elements Is Limited To The Germline Genome In Tetrahymena Thermophila, Jeffrey D. Wuitschick, Jill A. Gershan, Andrew J. Lochowicz, Shuqiang Li, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

In the ciliated protozoan Tetrahymena thermophila, extensive DNA elimination is associated with differentiation of the somatic macronucleus from the germline micronucleus. This study describes the isolation and complete characterization of Tlr elements, a family of approximately 30 micronuclear DNA sequences that are efficiently eliminated from the developing macronucleus. The data indicate that Tlr elements are comprised of an ~22 kb internal region flanked by complex and variable termini. The Tlr internal region is highly conserved among family members and contains 15 open reading frames, some of which resemble genes encoded by transposons and viruses. The Tlr termini appear to …

The Ecology Of Lianas And Their Role In Forests, Stefan A. Schnitzer, Frans Bongers

Biological Sciences Faculty Research and Publications

Recent studies have demonstrated the increasingly important role of lianas (woody vines) in forest regeneration, species diversity and ecosystem-level processes, particularly in the tropics. Mechanisms responsible for the maintenance of liana species diversity could yield new insights into the maintenance of overall species diversity. Lianas contribute to forest regeneration and competition, not only by competing directly with trees, but also by differentially affecting tree species and thus changing how trees compete among themselves. In addition, they contribute considerably to ecosystem-level processes, such as whole-forest transpiration and carbon sequestration. As the rate of tropical forest disturbance increases, they are likely to …

Dual Requirement For Yeast Hnrnp Nab2p In Mrna Poly(A) Tail Length Control And Nuclear Export, Ronald E. Hector, Keith R. Nykamp, Sonia Dheur, James T. Anderson, Priscilla J. Non, Carl R. Urbinati, Scott M. Wilson, Lionel Minvielle‐Sebastia, Maurice S. Swanson

Biological Sciences Faculty Research and Publications

Recent studies of mRNA export factors have provided additional evidence for a mechanistic link between mRNA 3′‐end formation and nuclear export. Here, we identify Nab2p as a nuclear poly(A)‐binding protein required for both poly(A) tail length control and nuclear export of mRNA. Loss of NAB2 expression leads to hyperadenylation and nuclear accumulation of poly(A)⁺ RNA but, in contrast to mRNA export mutants, these defects can be uncoupled in a nab2 mutant strain. Previous studies have implicated the cytoplasmic poly(A) tail‐binding protein Pab1p in poly(A) tail length control during polyadenylation. Although cells are viable in the absence of NAB2 expression …

Serotonin Modulates Oscillations Of The Membrane Potential In Isolated Spinal Neurons From Lampreys, I. V. Batueva, James Buchanan, N. P. Veselkin, E. I. Suderevskaya, E. A. Tsvetkov

Biological Sciences Faculty Research and Publications

Studies were performed on spinal neurons from lampreys isolated by an enzymatic/mechanical method using pronase. The effects of 100 µM serotonin (5-HT) on membrane potential oscillations induced by a variety of excitatory amino acids were studied. 5-HT was found to depolarize branched cells (presumptive motoneurons and interneurons) by 2–6 mV without inducing membrane potential oscillations. However, when oscillations were already present because of an excitatory amino acid, 5-HT changed the parameters of these oscillations, increasing the amplitudes of all types of oscillations, increasing the frequency of irregular oscillations, and increasing the duration of the depolarization plateaus accompanied by action potentials. …

Smooth Muscle Myosin Heavy Chain Isoform Distribution In The Swine Stomach, Jonathan A. Parisi, Thomas J. Eddinger

Biological Sciences Faculty Research and Publications

To evaluate the distribution of smooth muscle myosin heavy chain isoforms (SMB, with head insert), we examined frozen sections from the various regions of swine stomachs using isoform-specific antibodies. We previously reported variable SMB myosin heavy chain (MHC) expression in stomach cells that correlates with unloaded shortening velocities. This is consistent with the generalization of tonic fundic muscle having low expression and phasic antral muscle having high expression of the SMB MHC isoform. Using immunohistochemistry (IHC), we show a progression of the SMB MHC from very low immunoreactivity in the fundus to very intense immunoreactivity in the antrum. In the …

A Novel Family Of Mobile Genetic Elements Is Limited To The Germline Genome In Tetrahymena Thermophila, Jeffrey D. Wuitschick, Jill A. Gershan, Andrew J. Lochowicz, Shuqiang Li, Kathleen M. Karrer

Biological Sciences Faculty Research and Publications

In the ciliated protozoan Tetrahymena thermophila, extensive DNA elimination is associated with differentiation of the somatic macronucleus from the germline micronucleus. This study describes the isolation and complete characterization of Tlr elements, a family of approximately 30 micronuclear DNA sequences that are efficiently eliminated from the developing macronucleus. The data indicate that Tlr elements are comprised of an ∼22 kb internal region flanked by complex and variable termini. The Tlr internal region is highly conserved among family members and contains 15 open reading frames, some of which resemble genes encoded by transposons and viruses. The Tlr termini appear to …

Spinal Cord Of Lamprey, James T. Buchanan

Biological Sciences Faculty Research and Publications

No abstract provided.

Methylation Of Adenine In The Nuclear Dna Of "Tetrahymena" Is Internucleosomal And Independent Of Histone H1, Kathleen M. Karrer, Teresa Ann Van Nuland

Biological Sciences Faculty Research and Publications

There are about 50 copies of each chromosome in the somatic macronucleus of the ciliated protozoan Tetrahymena. Approximately 0.8% of the adenine residues in the macronuclear DNA of Tetrahymena are methylated to N⁶-methyladenine. The degree of methylation varies between sites from a very low percentage to >90%. In this study a correlation was found between nucleosome positioning and DNA methylation. Eight GATC sites with different levels of methylation were examined. There was a direct correlation between the degree of methylation and proximity to linker DNA at these sites. Although methylation occurs preferentially in linker DNA, the patterns …

The Effects Of Serotonin On Functionally Diverse Isolated Lamprey Spinal Cord Neurons, I. V. Batueva, James T. Buchanan, N. P. Veselkin, E. I. Suderevskaya, E. A. Tsvetkov

Biological Sciences Faculty Research and Publications

The experiments reported here showed that application of serotonin (5-hydroxytryptamine, 5-HT) (100 µ M) did not induce any significant current through the membranes of any of the spinal neurons studied (n = 62). At the same time, the membranes of most motoneurons and interneurons (15 of 18) underwent slight depolarization (2–6 mV) in the presence of 5-HT, which was not accompanied by any change in the input resistance of the cells. Depolarization to 10–20 mV occurred in some cells (3 of 18) of these functional groups, this being accompanied by 20–60% decreases in input resistance. The same concentration of 5-HT …