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Articles 1 - 21 of 21
Full-Text Articles in Life Sciences
Adverse Effects Of Chronic Circadian Desynchronization In Animals In A "Challenging" Environment, Fabian Preuss, Tueming Tang, Aaron D. Laposky, Deanna M. Arble, Ali Keshavarzian, Fred W. Turek
Adverse Effects Of Chronic Circadian Desynchronization In Animals In A "Challenging" Environment, Fabian Preuss, Tueming Tang, Aaron D. Laposky, Deanna M. Arble, Ali Keshavarzian, Fred W. Turek
Biological Sciences Faculty Research and Publications
Continuous disruption of circadian rhythms, as seen in human shift workers, has been associated with the development of a number of adverse mental and physiological conditions. However, scientific evidence linking circadian disruption to overall health, particularly in animal models, is not well documented. In this study, we have demonstrated that exposing C57BL/6J mice to 12-h phase shifts every 5 days for 3 mo had no effect on body weight or intestinal physiology. However, when animals were further challenged with dextran sodium sulfate to induce colitis, chronic shifting of the light-dark cycle led to a dramatic increase in the progression of …
Phylogeography Of The Bigeye Chub Hybopsis Amblops (Teleostei: Cypriniformes): Early Pleistocene Diversification And Post‐Glacial Range Expansion, Peter B. Berendzen, Tony Gamble, Andrew M. Simons
Phylogeography Of The Bigeye Chub Hybopsis Amblops (Teleostei: Cypriniformes): Early Pleistocene Diversification And Post‐Glacial Range Expansion, Peter B. Berendzen, Tony Gamble, Andrew M. Simons
Biological Sciences Faculty Research and Publications
The bigeye chub, Hybopsis amblops, is a member of the Central Highlands ichthyofauna of eastern North America. Phylogenetic analyses of the H. amblops species group based on a 1059 bp fragment of the mitochondrial DNA cytochrome b gene did not recover a monophyletic group. The inclusion of Hybopsis hypsinotus in the species complex is questionable. Within H. amblops, five strongly supported clades were identified; two clades containing haplotypes from the Ozark Highlands and three clades containing haplotypes from the Eastern Highlands and previously glaciated regions of the Ohio and Wabash River drainages. Estimates of the timing of divergence …
The Yeast Aac2 Protein Exists In Physical Association With The Cytochrome Bc1-Cox Supercomplex And The Tim23 Machinery, Mary Kathryn Dienhart, Rosemary A. Stuart
The Yeast Aac2 Protein Exists In Physical Association With The Cytochrome Bc1-Cox Supercomplex And The Tim23 Machinery, Mary Kathryn Dienhart, Rosemary A. Stuart
Biological Sciences Faculty Research and Publications
The ADP/ATP carrier (AAC) proteins play a central role in cellular metabolism as they facilitate the exchange of ADP and ATP across the mitochondrial inner membrane. We present evidence here that in yeast (Saccharomyces cerevisiae) mitochondria the abundant Aac2 isoform exists in physical association with the cytochrome c reductase (cytochrome bc1)-cytochrome c oxidase (COX) supercomplex and its associated TIM23 machinery. Using a His-tagged Aac2 derivative and affinity purification studies, we also demonstrate here that the Aac2 isoform can be affinity-purified with other AAC proteins. Copurification of the Aac2 protein with the TIM23 machinery can occur independently …
Limited Native Plant Regeneration In Novel, Exotic-Dominated Forests On Hawai’I, Joseph Mascaro, Kristen K. Becklund, R. Flint Hughes, Stefan A. Schnitzer
Limited Native Plant Regeneration In Novel, Exotic-Dominated Forests On Hawai’I, Joseph Mascaro, Kristen K. Becklund, R. Flint Hughes, Stefan A. Schnitzer
Biological Sciences Faculty Research and Publications
Ecological invasions are a major driver of global environmental change. When invasions are frequent and prolonged, exotic species can become dominant and ultimately create novel ecosystem types. These ecosystems are now widespread globally. Recent evidence from Puerto Rico suggests that exotic-dominated forests can provide suitable regeneration sites for native species and promote native species abundance, but this pattern has been little explored elsewhere. We surveyed 46 sites in Hawai’i to determine whether native species occurred in the understories of exotic-dominated forests. Native trees smaller than 10 cm in diameter were absent in 28 of the 46 sites and rare in …
Cellular And Synaptic Actions Of Acetylcholine In The Lamprey Spinal Cord, Katharina A. Quinlan, James T. Buchanan
Cellular And Synaptic Actions Of Acetylcholine In The Lamprey Spinal Cord, Katharina A. Quinlan, James T. Buchanan
Biological Sciences Faculty Research and Publications
This study investigated cellular and synaptic mechanisms of cholinergic neuromodulation in the in vitro lamprey spinal cord. Most spinal neurons tested responded to local application of acetylcholine (ACh) with depolarization and decreased input resistance. The depolarization persisted in the presence of either tetrodotoxin or muscarinic antagonist scopolamine and was abolished with nicotinic antagonist mecamylamine, indicating a direct depolarization through nicotinic ACh receptors. Local application of muscarinic ACh agonists modulated synaptic strength in the spinal cord by decreasing the amplitude of unitary excitatory and inhibitory postsynaptic potentials. The postsynaptic response to direct application of glutamate was unchanged by muscarinic agonists, suggesting …
Vibration Causes Acute Vascular Injury In A Two-Step Process: Vasoconstriction And Vacuole Disruption, Sandya R. Govindaraju, James L. W. Bain, Thomas J. Eddinger, Danny A. Riley
Vibration Causes Acute Vascular Injury In A Two-Step Process: Vasoconstriction And Vacuole Disruption, Sandya R. Govindaraju, James L. W. Bain, Thomas J. Eddinger, Danny A. Riley
Biological Sciences Faculty Research and Publications
Hand–arm vibration syndrome is a vasospastic and neurodegenerative occupational disease. In the current study, the mechanism of vibration- induced vascular smooth muscle cell (SMC) injury was examined in a rat-tail vibration model. Tails of male Sprague Dawley rats were vibrated continuously for 4 hr at 60 Hz, 49 m/s2 with or without general anesthesia. Ventral tail arteries were aldehyde fixed and embedded in epoxy resin to enable morphological analysis. Vibration without anesthesia caused vasoconstriction and vacuoles in the SMC. Anesthetizing rats during vibration prevented vasoconstriction and vacuole formation. Exposing tail arteries in situ to 1 mM norepinephrine (NE) for 15 …
Species Limits And Phylogeography Of North American Cricket Frogs (Acris: Hylidae), Tony Gamble, Peter B. Berendzen, H. Bradley Shaffer, David E. Starkey, Andrew M. Simons
Species Limits And Phylogeography Of North American Cricket Frogs (Acris: Hylidae), Tony Gamble, Peter B. Berendzen, H. Bradley Shaffer, David E. Starkey, Andrew M. Simons
Biological Sciences Faculty Research and Publications
Cricket frogs are widely distributed across the eastern United States and two species, the northern cricket frog (Acris crepitans) and the southern cricket frog (A. gryllus) are currently recognized. We generated a phylogenetic hypothesis for Acris using fragments of nuclear and mitochondrial genes in separate and combined phylogenetic analyses. We also used distance methods and fixation indices to evaluate species limits within the genus and the validity of currently recognized subspecies of A. crepitans. The distributions of existing A. crepitans subspecies, defined by morphology and call types, do not match the distributions of evolutionary lineages recovered using …
Out Of The Blue: A Novel, Trans‐Atlantic Clade Of Geckos (Gekkota, Squamata), Tony Gamble, Aaron M. Bauer, Eli Greenbaum, Todd R. Jackman
Out Of The Blue: A Novel, Trans‐Atlantic Clade Of Geckos (Gekkota, Squamata), Tony Gamble, Aaron M. Bauer, Eli Greenbaum, Todd R. Jackman
Biological Sciences Faculty Research and Publications
Phylogenetic relationships among gekkotan lizards were estimated from five nuclear protein-coding genes in separate and combined analyses using maximum parsimony, maximum likelihood and Bayesian analyses. All analyses recovered a monophyletic trans-Atlantic gecko clade (Phyllodactylidae) consisting of the genera Asaccus, Haemodracon, Homonota, Phyllodactylus, Phyllopezus, Ptyodactylus, Tarentola and Thecadactylus. No other phylogenetic or taxonomic hypotheses have proposed linking these genera, which have been consistently grouped with other taxa outside of the clade. In this paper, we determine the relationships of this new clade to other major gekkotan groups, evaluate previous phylogenetic hypotheses regarding constituent members of this novel clade, and critically …
Cloning Of The Neurodegeneration Gene Drop-Dead And Characterization Of Additional Phenotypes Of Its Mutation, Edward M. Blumenthal
Cloning Of The Neurodegeneration Gene Drop-Dead And Characterization Of Additional Phenotypes Of Its Mutation, Edward M. Blumenthal
Biological Sciences Faculty Research and Publications
Mutations in the Drosophila gene drop-dead (drd) result in early adult lethality and neurodegeneration, but the molecular identity of the drd gene and its mechanism of action are not known. This paper describes the characterization of a new X-linked recessive adult-lethal mutation, originally called lot's wife (lwf1) but subsequently identified as an allele of drd (drdlwf); drdlwf mutants die within two weeks of eclosion. Through mapping and complementation, the drd gene has been identified as CG33968, which encodes a putative integral membrane protein of unknown function. The drdlwf allele is associated …
Weak Competition Among Tropical Tree Seedlings: Implications For Species Coexistence, C.E. Timothy Paine, Kyle E. Harms, Stefan A. Schnitzer, Walter P. Carson
Weak Competition Among Tropical Tree Seedlings: Implications For Species Coexistence, C.E. Timothy Paine, Kyle E. Harms, Stefan A. Schnitzer, Walter P. Carson
Biological Sciences Faculty Research and Publications
The intensity of competition among forest tree seedlings is poorly understood, but has important ramifications for their recruitment and for the maintenance of species diversity. Intense competition among seedlings could allow competitively dominant species to exclude subordinate species. Alternatively, the low density and small stature of forest tree seedlings could preclude intense interseedling competition. In this case, other processes, such as size‐asymmetric competition with adults, interactions with consumers, or neutral dynamics would prevail as those structuring the forest understory. We tested the intensity of, and potential for, intraspecific competition among tree seedlings of three species (Brosimum alicastrum, Matisia …
Contribution Of Cystine-Glutamate Antiporters To The Psychotomimetic Effects Of Phencyclidine, David A. Baker, Aric Madayag, Lars V. Kristiansen, James H. Meador-Woodruff, Vahram Haroutunian, Ilangovan Raju
Contribution Of Cystine-Glutamate Antiporters To The Psychotomimetic Effects Of Phencyclidine, David A. Baker, Aric Madayag, Lars V. Kristiansen, James H. Meador-Woodruff, Vahram Haroutunian, Ilangovan Raju
Biological Sciences Faculty Research and Publications
Altered glutamate signaling contributes to a myriad of neural disorders, including schizophrenia. While synaptic levels are intensely studied, nonvesicular release mechanisms, including cystine–glutamate exchange, maintain high steady-state glutamate levels in the extrasynaptic space. The existence of extrasynaptic receptors, including metabotropic group II glutamate receptors (mGluR), pose nonvesicular release mechanisms as unrecognized targets capable of contributing to pathological glutamate signaling. We tested the hypothesis that activation of cystine–glutamate antiporters using the cysteine prodrug N-acetylcysteine would blunt psychotomimetic effects in the rodent phencyclidine (PCP) model of schizophrenia. First, we demonstrate that PCP elevates extracellular glutamate in the prefrontal cortex, an effect …
Requirement Of A Plasmid-Encoded Catalase For Survival Of Rhizobium Etli Cfn42 In A Polyphenol-Rich Environment, Alejandro García-De Los Santos, Erika López, Ciro A. Cubillas, K. Dale Noel, Susana Brom, David Romero
Requirement Of A Plasmid-Encoded Catalase For Survival Of Rhizobium Etli Cfn42 In A Polyphenol-Rich Environment, Alejandro García-De Los Santos, Erika López, Ciro A. Cubillas, K. Dale Noel, Susana Brom, David Romero
Biological Sciences Faculty Research and Publications
Nitrogen-fixing bacteria collectively called rhizobia are adapted to live in polyphenol-rich environments. The mechanisms that allow these bacteria to overcome toxic concentrations of plant polyphenols have not been clearly elucidated. We used a crude extract of polyphenols released from the seed coat of the black bean to simulate a polyphenol-rich environment and analyze the response of the bean-nodulating strain Rhizobium etli CFN42. Our results showed that the viability of the wild type as well as that of derivative strains cured of plasmids p42a, p42b, p42c, and p42d or lacking 200 kb of plasmid p42e was not affected in this environment. …
Supplemental Protocol For Liana Censuses, Stefan A. Schnitzer, Suzanne Rutishauser, Salomón Aguilar
Supplemental Protocol For Liana Censuses, Stefan A. Schnitzer, Suzanne Rutishauser, Salomón Aguilar
Biological Sciences Faculty Research and Publications
Lianas affect many aspects of tropical forest dynamics and thus the study of their ecology is critical for a comprehensive understanding of tropical forest ecology. Recently, we initiated a complete census of all lianas ≥1 cm diameter in the 50 ha forest dynamics plot on Barro Colorado Island, Panama using the census protocol developed by Gerwing et al. [Gerwing, J.J., Schnitzer, S.A., Burnham, R.J., Bongers, F., Chave, J., DeWalt, S.J., Ewango, C.E.N., Foster, R., Kenfack, D., Martinez-Ramos, M., Parren, M., Parthasarathy, N., Perez-Salicrup, D.R., Putz, F.E., Thomas, D.W., 2006. A standard protocol for liana censuses. Biotropica 38, 256–261]. This protocol …
Biomass And Toxicity Responses Of Poison Ivy (Toxicodendron Radicans) To Elevated Atmospheric Co2: Comment, Stefan A. Schnitzer, Ronald A. Londre, John Klironomos, Peter B. Reich
Biomass And Toxicity Responses Of Poison Ivy (Toxicodendron Radicans) To Elevated Atmospheric Co2: Comment, Stefan A. Schnitzer, Ronald A. Londre, John Klironomos, Peter B. Reich
Biological Sciences Faculty Research and Publications
No abstract provided.
Degradation Of Hypomodified TrnaIMet In Vivo Involves Rna-Dependent Atpase Activity Of The Dexh Helicase Mtr4p, Xuying Wang, Huijue Jia, Eckhard Jankowsky, James T. Anderson
Degradation Of Hypomodified TrnaIMet In Vivo Involves Rna-Dependent Atpase Activity Of The Dexh Helicase Mtr4p, Xuying Wang, Huijue Jia, Eckhard Jankowsky, James T. Anderson
Biological Sciences Faculty Research and Publications
Effective turnover of many incorrectly processed RNAs in yeast, including hypomodified tRNAi Met, requires the TRAMP complex, which appends a short poly(A) tail to RNA designated for decay. The poly(A) tail stimulates degradation by the exosome. The TRAMP complex contains the poly(A) polymerase Trf4p, the RNA-binding protein Air2p, and the DExH RNA helicase Mtr4p. The role of Mtr4p in RNA degradation processes involving the TRAMP complex has been unclear. Here we show through a genetic analysis that MTR4 is required for degradation but not for polyadenylation of hypomodified tRNAi Met. A suppressor of the trm6-504 mutation …
The Spinobulbar System In Lamprey, James T. Buchanan, James F. Einum
The Spinobulbar System In Lamprey, James T. Buchanan, James F. Einum
Biological Sciences Faculty Research and Publications
Locomotor networks in the spinal cord are controlled by descending systems which in turn receive feedback signals from ascending systems about the state of the locomotor networks. In lamprey, the ascending system consists of spinobulbar neurons which convey spinal network signals to the two descending systems, the reticulospinal and vestibulospinal neurons. Previous studies showed that spinobulbar neurons consist of both ipsilaterally and contralaterally projecting cells distributed at all rostrocaudal levels of the spinal cord, though most numerous near the obex. The axons of spinobulbar neurons ascend in the ventrolateral spinal cord and brainstem to the caudal mesencephalon and within the …
Mitochondrial Biogenesis: Is An Old Dog Still Teaching Us New Tricks? Meeting On The Assembly Of The Mitochondrial Respiratory Chain, Rosemary A. Stuart, Peter Rehling
Mitochondrial Biogenesis: Is An Old Dog Still Teaching Us New Tricks? Meeting On The Assembly Of The Mitochondrial Respiratory Chain, Rosemary A. Stuart, Peter Rehling
Biological Sciences Faculty Research and Publications
No abstract provided.
Effect Of Ethanol On Microbial Community Structure And Function During Natural Attenuation Of Benzene, Toluene, And O-Xylene In A Sulfate-Reducing Aquifer, Kevin Feris, Doug Mackay, Nick De Sieyes, Irina Chakraborty, Murray Einarson, Krassimira R. Hristova, Kate M. Scow
Effect Of Ethanol On Microbial Community Structure And Function During Natural Attenuation Of Benzene, Toluene, And O-Xylene In A Sulfate-Reducing Aquifer, Kevin Feris, Doug Mackay, Nick De Sieyes, Irina Chakraborty, Murray Einarson, Krassimira R. Hristova, Kate M. Scow
Biological Sciences Faculty Research and Publications
Ethanol (EtOH) is a commonly used fuel oxygenate in reformulated gasoline and is an alternative fuel and fuel supplement. Effects of EtOH release on aquifer microbial ecology and geochemistry have not been well characterized in situ. We performed a controlled field release of petroleum constituents (benzene (B), toluene (T), o-xylene (o-X) at ∼1–3 mg/L each) with and without EtOH (∼500 mg/L). Mixed linear modeling (MLM) assessed effects on the microbial ecology of a naturally sulfidic aquifer and how the microbial community affected B, T, and o-X plume lengths and aquifer geochemistry. Changes in microbial community structure …
Dimeric Heat Shock Protein 40 Binds Radial Spokes For Generating Coupled Power Strokes And Recovery Strokes Of 9 + 2 Flagella, Chun Yang, Heather A. Owen, Pinfen Yang
Dimeric Heat Shock Protein 40 Binds Radial Spokes For Generating Coupled Power Strokes And Recovery Strokes Of 9 + 2 Flagella, Chun Yang, Heather A. Owen, Pinfen Yang
Biological Sciences Faculty Research and Publications
T-shape radial spokes regulate flagellar beating. However, the precise function and molecular mechanism of these spokes remain unclear. Interestingly, Chlamydomonas reinhardtii flagella lacking a dimeric heat shock protein (HSP) 40 at the spokehead–spokestalk juncture appear normal in length and composition but twitch actively while cells jiggle without procession, resembling a central pair (CP) mutant. HSP40− cells begin swimming upon electroporation with recombinant HSP40. Surprisingly, the rescue doesn't require the signature DnaJ domain. Furthermore, the His-Pro-Asp tripeptide that is essential for stimulating HSP70 adenosine triphosphatase diverges in candidate orthologues, including human DnaJB13. Video microscopy reveals hesitance in bend initiation and …
Amp-Activated Protein Kinase Is Involved In Hormone-Induced Mouse Oocyte Meiotic Maturation In Vitro, Jing Chen, Stephen Downs
Amp-Activated Protein Kinase Is Involved In Hormone-Induced Mouse Oocyte Meiotic Maturation In Vitro, Jing Chen, Stephen Downs
Biological Sciences Faculty Research and Publications
We have previously shown that AMP-activated protein kinase (AMPK) can induce the resumption of meiosis in mouse oocytes maintained in meiotic arrest in vitro. The present study was carried out to determine whether AMPK activation is involved in hormone-induced maturation. Follicle-stimulating hormone (FSH) and the EGF-like peptide, amphiregulin (AR), are potent inducers of maturation in cumulus cell-enclosed oocytes (CEO). Within 3 h of FSH treatment, phospho-acetyl CoA carboxylase (ACC) levels were increased in germinal vesicle (GV)-stage oocytes when compared to non-stimulated controls and remained elevated throughout 9 h of culture, indicating AMPK activation. A similar response to AR was observed …
Tertiary Climate Change And The Diversification Of The Amazonian Gecko Genus Gonatodes (Sphaerodactylidae, Squamata), Tony Gamble, Andrew M. Simons, Guarino R. Colli, Laurie J. Vitt
Tertiary Climate Change And The Diversification Of The Amazonian Gecko Genus Gonatodes (Sphaerodactylidae, Squamata), Tony Gamble, Andrew M. Simons, Guarino R. Colli, Laurie J. Vitt
Biological Sciences Faculty Research and Publications
The genus Gonatodes is a monophyletic group of small-bodied, diurnal geckos distributed across northern South America, Central America, and the Caribbean. We used fragments of three nuclear genes (RAG2, ACM4, and c-mos) and one mitochondrial gene (16S) to estimate phylogenetic relationships among Amazonian species of Gonatodes. We used Penalized Likelihood to estimate timing of diversification in the genus. Most cladogenesis occurred in the Oligocene and early Miocene and coincided with a burst of diversification in other South American animal groups including mollusks, birds, and mammals. The Oligocene and early Miocene were periods dominated by …