Biology Commons^™

Liana Impacts On Carbon Cycling, Storage And Sequestration In Tropical Forests, Geertje M. Van Der Heijden, Stefan A. Schnitzer, Jennifer S. Powers, Oliver L. Phillips

Biological Sciences Faculty Research and Publications

Mature tropical forests sequester large quantities of atmospheric CO2, which they store as plant biomass. These forests are changing however, including an increase in liana abundance and biomass over recent decades in Neotropical forests. We ask here how this increase in lianas might impact the tropical forest carbon cycle and their capacity for carbon storage and sequestration. Lianas reduce tree growth, survival, and leaf productivity; however, lianas also invest significantly in leaf production, and the increase in lianas could conceivably offset liana‐induced reductions in tree canopy productivity with no adverse effects to the forest‐level canopy productivity. By contrast, lianas decrease …

Multiple C-Terminal Tails Within A Single E. Coli Ssb Homotetramer Coordinate Dna Replication And Repair, Edwin Antony, Elizabeth Weiland, Quan Yuan, Carol M. Manhart, Binh Nguyen, Alexander G. Kozlov, Charles S. Mchenry, Timothy M. Lohman

Biological Sciences Faculty Research and Publications

Escherichia coli single-stranded DNA binding protein (SSB) plays essential roles in DNA replication, recombination and repair. SSB functions as a homotetramer with each subunit possessing a DNA binding domain (OB-fold) and an intrinsically disordered C-terminus, of which the last nine amino acids provide the site for interaction with at least a dozen other proteins that function in DNA metabolism. To examine how many C-termini are needed for SSB function, we engineered covalently linked forms of SSB that possess only one or two C-termini within a four-OB-fold “tetramer”. Whereas E. coli expressing SSB with only two tails can survive, expression …

Left–Right Dewlap Asymmetry And Phylogeography Of Anolis Lineatus On Aruba And Curaçao, Gabriel E.A. Gartner, Tony Gamble, Alexander L. Jaffe, Alexis Harrison, Jonathan B. Losos

Biological Sciences Faculty Research and Publications

Anolis lizards exhibit a remarkable degree of diversity in the shape, colour, pattern and size of their dewlaps. Asymmetry, where one side of the dewlap differs in pattern or colour from the other, has only been reported in one species, Anolis lineatus, and then on only one of the two islands from which it occurs. Given the importance of the dewlap in intra- and interspecific signalling, we expanded on previous work by (1) investigating whether the reported asymmetry actually occurs and, if so, whether it occurs on animals from both Aruba and Curaçao; (2) examining whether populations differ in …

Effects Of Prolonged Space Flight On Human Skeletal Muscle Enzyme And Substrate Profiles, Robert H. Fitts, Patricia Colloton, Scott Trappe, J. L. Bain, Danny A. Riley

Biological Sciences Faculty Research and Publications

Our primary goal was to determine the effects of 6-mo flight on the International Space Station (ISS) on selected anaerobic and aerobic enzymes, and the content of glycogen and lipids in slow and fast fibers of the soleus and gastrocnemius. Following local anesthesia, biopsies were obtained from nine ISS crew members ∼45 days preflight and on landing day (R+0) postflight. We subdivided the crew into those who ran 200 min/wk or more (high treadmill, HT) in-flight from those who ran /wk (low treadmill, LT). In the LT group, there was a loss of lipid in soleus type I fibers, and …

Tonic And Phasic Smooth Muscle Contraction Is Not Regulated By The Pkcα - Cpi-17 Pathway In Swine Stomach Antrum And Fundus, Yu Zhang, Meghan E. Hermanson, Thomas J. Eddinger

Biological Sciences Faculty Research and Publications

Regulation of myosin light chain phosphatase (MLCP) via protein kinase C (PKC) and the 17 kDa PKC-potentiated inhibitor of myosin light chain phosphatase (CPI-17) has been reported as a Ca²⁺ sensitization signaling pathway in smooth muscle (SM), and thus may be involved in tonic vs. phasic contractions. This study examined the protein expression and spatial-temporal distribution of PKCα and CPI-17 in intact SM tissues. KCl or carbachol (CCh) stimulation of tonic stomach fundus SM generates a sustained contraction while the phasic stomach antrum generates a transient contraction. In addition, the tonic fundus generates greater relative force than phasic antrum …

Are Lianas More Drought-Tolerant Than Trees? A Test For The Role Of Hydraulic Architecture And Other Stem And Leaf Traits, Masha T. Van Der Sande, Lourens Poorter, Stefan A. Schnitzer, Lars Markesteijn

Biological Sciences Faculty Research and Publications

Lianas are an important component of Neotropical forests, where evidence suggests that they are increasing in abundance and biomass. Lianas are especially abundant in seasonally dry tropical forests, and as such it has been hypothesized that they are better adapted to drought, or that they are at an advantage under the higher light conditions in these forests. However, the physiological and morphological characteristics that allow lianas to capitalize more on seasonal forest conditions compared to trees are poorly understood. Here, we evaluate how saplings of 21 tree and liana species from a seasonal tropical forest in Panama differ in cavitation …

Srs2 Prevents Rad51 Filament Formation By Repetitive Motion On Dna, Yupeng Qiu, Edwin Antony, Sultan Doganay, Hye Ran Koh, Timothy M. Lohman, Sua Myong

Biological Sciences Faculty Research and Publications

Srs2 dismantles presynaptic Rad51 filaments and prevents its re-formation as an anti-recombinase. However, the molecular mechanism by which Srs2 accomplishes these tasks remains unclear. Here we report a single-molecule fluorescence study of the dynamics of Rad51 filament formation and its disruption by Srs2. Rad51 forms filaments on single-stranded DNA by sequential binding of primarily monomers and dimers in a 5′–3′ direction. One Rad51 molecule binds to three nucleotides, and six monomers are required to achieve a stable nucleation cluster. Srs2 exhibits ATP-dependent repetitive motion on single-stranded DNA and this activity prevents re-formation of the Rad51 filament. The same activity of …

A Requirement For Fatty Acid Oxidation In The Hormone-Induced Meiotic Maturation Of Mouse Oocytes, Deepa Valsangkar, Stephen M. Downs

Biological Sciences Faculty Research and Publications

We have previously shown that fatty acid oxidation (FAO) is required for AMP-activated protein kinase (PRKA)-induced maturation in vitro. In the present study, we have further investigated the role of this metabolic pathway in hormone-induced meiotic maturation. Incorporating an assay with ³H-palmitic acid as the substrate, we first examined the effect of PRKA activators on FAO levels. There was a significant stimulation of FAO in cumulus cell-enclosed oocytes (CEO) treated with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and RSVA405. In denuded oocytes (DO), AICAR stimulated FAO only in the presence of carnitine, the molecule that facilitates fatty acyl CoA entry into the …

A Substrate-Induced Biotin Binding Pocket In The Carboxyltransferase Domain Of Pyruvate Carboxylase, Adam D. Lietzan, Martin St. Maurice

Biological Sciences Faculty Research and Publications

Biotin-dependent enzymes catalyze carboxyl transfer reactions by efficiently coordinating multiple reactions between spatially distinct active sites. Pyruvate carboxylase (PC), a multifunctional biotin-dependent enzyme, catalyzes the bicarbonate- and MgATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To complete the overall reaction, the tethered biotin prosthetic group must first gain access to the biotin carboxylase domain and become carboxylated and then translocate to the carboxyltransferase domain, where the carboxyl group is transferred from biotin to pyruvate. Here, we report structural and kinetic evidence for the formation of a substrate-induced biotin binding pocket in the carboxyltransferase domain of …

Neurodegeneration In Drop-Dead Mutant Drosophila Melanogaster Is Associated With The Respiratory System But Not With Hypoxia, Christine Lynn Sansone, Edward M. Blumenthal

Biological Sciences Faculty Research and Publications

Mutations in the gene drop-dead (drd) cause diverse phenotypes in adult Drosophila melanogaster including early lethality, neurodegeneration, tracheal defects, gut dysfunction, reduced body mass, and female sterility. Despite the identification of the drd gene itself, the causes of early lethality and neurodegeneration in the mutant flies remain unknown. To determine the pattern of drd expression associated with the neurodegenerative phenotype, knockdown of drd with various Gal4 drivers was performed. Early adult lethality and neurodegeneration were observed upon knockdown of drd in the tracheal system with two independent insertions of the breathless-Gal4 driver and upon knockdown in the tracheal …

Nonspecific, Reversible Inhibition Of Voltage-Gated Calcium Channels By Camkii Inhibitor Ck59, Andrew S. Kahrls, Michelle Mynlieff

Biological Sciences Faculty Research and Publications

Investigation of kinase-related processes often uses pharmacological inhibition to reveal pathways in which kinases are involved. However, one concern about using such kinase inhibitors is their potential lack of specificity. Here, we report that the calcium–calmodulin-dependent kinase II (CaMKII) inhibitor CK59 inhibited multiple voltage-gated calcium channels, including the L-type channel during depolarization in a dose-dependent manner. The use of another CaMKII inhibitor, cell-permeable autocamtide-2 related inhibitory peptide II (Ant-AIP-II), failed to similarly decrease calcium current or entry in hippocampal cultures, as shown by ratiometric calcium imaging and whole-cell patch clamp electrophysiology. Notably, inhibition due to CK59 was reversible; washout of …

Roles Of Predicted Glycosyltransferases In The Biosynthesis Of The Rhizobium Etli Ce3 O Antigen, Kristylea J. Ojeda, Laurie Simonds, K. Dale Noel

Biological Sciences Faculty Research and Publications

The Rhizobium etli CE3 O antigen is a fixed-length heteropolymer. The genetic regions required for its synthesis have been identified, and the nucleotide sequences are known. The structure of the O antigen has been determined, but the roles of specific genes in synthesizing this structure are relatively unclear. Within the known O-antigen genetic clusters of this strain, nine open reading frames (ORFs) were found to contain a conserved glycosyltransferase domain. Each ORF was mutated, and the resulting mutant lipopolysaccharide (LPS) was analyzed. Tricine SDS-PAGE revealed stepwise truncations of the O antigen that were consistent with differences in mutant LPS sugar …

Inhibition Of Diuretic Stimulation Of An Insect Secretory Epithelium By A Cgmp-Dependent Protein Kinase, Kristen A. Ruka, Anna P. Miller, Edward M. Blumenthal

Biological Sciences Faculty Research and Publications

The rate of urine secretion by insect Malpighian tubules (MTs) is regulated by multiple diuretic and antidiuretic hormones, often working either synergistically or antagonistically. In the Drosophila melanogaster MT, only diuretic factors have been reported. Two such agents are the biogenic amine tyramine (TA) and the peptide drosokinin (DK), both of which act on the stellate cells of the tubule to increase transepithelial chloride conductance. In the current study, TA and DK signaling was quantified by microelectrode recording of the transepithelial potential in isolated Drosophila MTs. Treatment of tubules with cGMP caused a significant reduction in the depolarizing responses to …

Antifreeze Proteins In The Primary Urine Of Larvae Of The Beetle Dendroides Canadensis, Philip K. Nickell, Sandra Sass, Dawn Verleye, Edward M. Blumenthal, John G. Duman

Biological Sciences Faculty Research and Publications

To avoid freezing while overwintering beneath the bark of fallen trees, Dendroides canadensis (Coleoptera: Pyrochroidae) larvae produce a family of antifreeze proteins (DAFPs) that are transcribed in specific tissues and have specific compartmental fates. DAFPs and associated thermal hysteresis activity (THA) have been shown previously in hemolymph and midgut fluid, but the presence of DAFPs has not been explored in primary urine, a potentially important site that can contain endogenous ice-nucleating compounds that could induce freezing. A maximum mean THA of 2.65±0.33°C was observed in primary urine of winter-collected D. canadensis larvae. THA in primary urine increased significantly through autumn, …

Increasing Liana Abundance And Basal Area In A Tropical Forest: The Contribution Of Long‐Distance Clonal Colonization, Suzanne R. Yorke, Stefan A. Schnitzer, Joseph Mascaro, Susan G. Letcher, Walter P. Carson

Biological Sciences Faculty Research and Publications

Recent evidence suggests that liana abundance and biomass are increasing in Neotropical forests, representing a major structural change to tropical ecosystems. Explanations for these increases, however, remain largely untested. Over an 8‐yr period (1999–2007), we censused lianas in nine, 24 × 36 m permanent plots in old‐growth and selectively logged forest at La Selva Biological Station, Costa Rica to test whether: (1) liana abundance and basal area are increasing in this forest; (2) the increase is being driven by increased recruitment, decreased mortality, or both; and (3) long‐distance clonal colonization explains the increase in liana abundance and basal area. We …

Selenium Biotransformations In An Engineered Aquatic Ecosystem For Bioremediation Of Agricultural Wastewater Via Brine Shrimp Production, Radomir Schmidt, Prapakorn Tantoyotai, Sirine C. Fakra, Matthew A. Marcus, Soo In Yang, Ingrid J. Pickering, Gary S. BañUelos, Krassimira R. Hristova, John L. Freeman

Biological Sciences Faculty Research and Publications

An engineered aquatic ecosystem was specifically designed to bioremediate selenium (Se), occurring as oxidized inorganic selenate from hypersalinized agricultural drainage water while producing brine shrimp enriched in organic Se and omega-3 and omega-6 fatty acids for use in value added nutraceutical food supplements. Selenate was successfully bioremediated by microalgal metabolism into organic Se (seleno-amino acids) and partially removed via gaseous volatile Se formation. Furthermore, filterfeeding brine shrimp that accumulated this organic Se were removed by net harvest. Thriving in this engineered pond system, brine shrimp (Artemia franciscana Kellogg) and brine fly (Ephydridae sp.) have major ecological relevance as important food …

Confocal Imaging Of Transmembrane Voltage By Seer Of Di-8-Anepps, Carlo Manno, Lourdes Figueroa, Robert H. Fitts, Eduardo Rios

Biological Sciences Faculty Research and Publications

Imaging, optical mapping, and optical multisite recording of transmembrane potential (V_m) are essential for studying excitable cells and systems. The naphthylstyryl voltage-sensitive dyes, including di-8-ANEPPS, shift both their fluorescence excitation and emission spectra upon changes in V_m. Accordingly, they have been used for monitoring V_m in nonratioing and both emission and excitation ratioing modes. Their changes in fluorescence are usually much less than 10% per 100 mV. Conventional ratioing increases sensitivity to between 3 and 15% per 100 mV. Low sensitivity limits the value of these dyes, especially when imaged with low light systems …

Cns Control Of Glucose Metabolism: Response To Environmental Challenges, Deanna M. Arble, Darleen A. Sandoval

Biological Sciences Faculty Research and Publications

Over the last 15 years, considerable work has accumulated to support the role of the CNS in regulating postprandial glucose levels. As discussed in the first section of this review, the CNS receives and integrates information from afferent neurons, circulating hormones, and postprandially generated nutrients to subsequently direct changes in glucose output by the liver and glucose uptake by peripheral tissues. The second major component of this review focuses on the effects of external pressures, including high fat diet and changes to the light:dark cycle on CNS-regulating glucose homeostasis. We also discuss the interaction between these different pressures and how …

Complex Facilitation And Competition In A Temperate Grassland: Loss Of Plant Diversity And Elevated Co2 Have Divergent And Opposite Effects On Oak Establishment, Alexandra Wright, Stefan A. Schnitzer, Ian A. Dickie, Alex R. Gunderson, Gavriella A. Pinter, Scott A. Mangan, Peter B. Reich

Biological Sciences Faculty Research and Publications

Encroachment of woody vegetation into grasslands is a widespread phenomenon that alters plant community composition and ecosystem function. Woody encroachment is often the result of fire suppression, but it may also be related to changes in resource availability associated with global environmental change. We tested the relative strength of three important global change factors (CO₂ enrichment, nitrogen deposition, and loss of herbaceous plant diversity) on the first 3 years of bur oak (Quercus macrocarpa) seedling performance in a field experiment in central Minnesota, USA. We found that loss of plant diversity decreased initial oak survival but increased …

Synthetic Lethality Of Chk1 Inhibition Combined With P53 And/Or P21 Loss During A Dna Damage Response In Normal And Tumor Cells, Sofia Origanti, Shi-Rong Cai, A. Z. Munir, Lynn S. White, Helen Piwnica-Worms

Biological Sciences Faculty Research and Publications

Cell cycle checkpoints ensure genome integrity and are frequently compromised in human cancers. A therapeutic strategy being explored takes advantage of checkpoint defects in p53-deficient tumors in order to sensitize them to DNA-damaging agents by eliminating Chk1-mediated checkpoint responses. Using mouse models, we demonstrated that p21 is a key determinant of how cells respond to the combination of DNA damage and Chk1 inhibition (combination therapy) in normal cells as well as in tumors. Loss of p21 sensitized normal cells to the combination therapy much more than did p53 loss and the enhanced lethality was partially blocked by CDK inhibition. In …

Exogenous Delivery Of Chaperonin Subunit Fragment Apicct1 Modulates Mutant Huntingtin Cellular Phenotypes, Emily M. Sontag, Lukasz A. Joachimiak, Zhiqun Tan, Anthony Tomlinson, David E. Housman, Charles G. Glabe, Steven G. Potkin, Judith Frydman, Leslie M. Thompson

Biological Sciences Faculty Research and Publications

Aggregation of misfolded proteins is characteristic of a number of neurodegenerative diseases, including Huntington disease (HD). The CCT/TRiC (chaperonin containing TCP-1/TCP-1 ring) chaperonin complex can inhibit aggregation and cellular toxicity induced by expanded repeat Huntingtin (mHtt) fragments. The substrate-binding apical domain of CCT/TRiC subunit CCT1, ApiCCT1, is sufficient to inhibit aggregation of expanded repeat mHtt fragments in vitro, providing therapeutic promise for HD. However, a key hurdle in considering ApiCCT1 as a potential treatment is in delivery. Because ApiCCT1 has a region of similarity to the HIV Tat protein cell-transduction domain, we tested whether recombinant ApiCCT1 (ApiCCT1r) protein could enter …

Smb Myosin Heavy Chain Knockout Enhances Tonic Contraction And Reduces The Rate Of Force Generation In Ileum And Stomach Antrum, Qian Huang, Gopal J. Babu, Muthu Periasamy, Thomas J. Eddinger

Biological Sciences Faculty Research and Publications

The role of SMA and SMB smooth muscle myosin heavy chain (MHC) isoforms in tonic and phasic contractions was studied in phasic (longitudinal ileum and stomach circular antrum) and tonic (stomach circular fundus) smooth muscle tissues of SMB knockout mice. Knocking out the SMB MHC gene eliminated SMB MHC protein expression and resulted in upregulation of the SMA MHC protein without altering the total MHC protein level. Switching from SMB to SMA MHC protein expression decreased the rate of the force transient and increased the sustained tonic force in SMB^(−/−) ileum and antrum with high potassium (KPSS) but not …

The Conservation Status Of The World’S Reptiles, Tony Gamble

Biological Sciences Faculty Research and Publications

Effective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the …

A Transgenic Minipig Model Of Huntington's Disease, Monika Baxa, Marian Hruska-Plochan, Stefan Juhas, Petr Vodicka, Antonin Pavlok, Jana Juhasova, Atsushi Miyanohara, Tetsuya Nejime, Jiri Klima, Monika Macakova, Silvia Marsala, Andreas Weiss, Svatava Kubickova, Petra Musilova, Radek Vrtel, Emily M. Sontag, Leslie Thompson, Jan Schier, Hana Hansikova, David S. Howland, Elena Cattaneo, Marian Difiglia, Martin Marsala, Jan Motlik

Biological Sciences Faculty Research and Publications

Background: Some promising treatments for Huntington's disease (HD) may require pre-clinical testing in large animals. Minipig is a suitable species because of its large gyrencephalic brain and long lifespan. Objective: To generate HD transgenic (TgHD) minipigs encoding huntingtin (HTT)1–548 under the control of human HTT promoter. Methods: Transgenesis was achieved by lentiviral infection of porcine embryos. PCR assessment of gene transfer, observations of behavior, and postmortem biochemical and immunohistochemical studies were conducted. Results: One copy of the human HTT transgene encoding 124 glutamines integrated into chromosome 1 q24-q25 and successful germ line transmission occurred through successive generations (F0, F1, F2 …

Suppression Of Chemically Induced And Spontaneous Mouse Oocyte Activation By Amp-Activated Protein Kinase, Ru Ya, Stephen M. Downs

Biological Sciences Faculty Research and Publications

Oocyte activation is an important process triggered by fertilization that initiates embryonic development. However, parthenogenetic activation can occur either spontaneously or with chemical treatments. The LT/Sv mouse strain is genetically predisposed to spontaneous activation. LT oocytes have a cell cycle defect and are ovulated at the metaphase I stage instead of metaphase II. A thorough understanding of the female meiosis defects in this strain remains elusive. We have reported that AMP-activated protein kinase (PRKA) has an important role in stimulating meiotic resumption and promoting completion of meiosis I while suppressing premature parthenogenetic activation. Here we show that early activation of …

Liana Abundance, Diversity, And Distribution On Barro Colorado Island, Panama, Stefan A. Schnitzer, Scott A. Mangan, James W. Dalling, Claire Baldeck, Stephen P. Hubbell, Alicia Ledo, Helene C. Muller-Laudau, Michael F. Tobin, Salomón Aguilar, David Brassfield, Andres Hernandez, Suzanne Lao, Rolando Perez, Oldemar Valdes, Suzanne R. Yorke

Biological Sciences Faculty Research and Publications

Lianas are a key component of tropical forests; however, most surveys are too small to accurately quantify liana community composition, diversity, abundance, and spatial distribution – critical components for measuring the contribution of lianas to forest processes. In 2007, we tagged, mapped, measured the diameter, and identified all lianas ≥1 cm rooted in a 50-ha plot on Barro Colorado Island, Panama (BCI). We calculated liana density, basal area, and species richness for both independently rooted lianas and all rooted liana stems (genets plus clones). We compared spatial aggregation patterns of liana and tree species, and among liana species that varied …

Mir-786 Regulation Of A Fatty-Acid Elongase Contributes To Rhythmic Calcium-Wave Initiation In C. Elegans, Benedict J. Kemp, Erik Allman, Lois Immerman, Megan Mohnen, Maureen A. Peters, Keith Nerhke, Allison L. Abbott

Biological Sciences Faculty Research and Publications

Background: Rhythmic behaviors are ubiquitous phenomena in animals. In C. elegans, defecation is an ultradian rhythmic behavior: every ∼50 s a calcium wave initiating in the posterior intestinal cells triggers the defecation motor program that comprises three sequential muscle contractions. Oscillatory calcium signaling is central to the periodicity of defecation. The posteriormost intestinal cells function as the pacemaker for this rhythmic behavior, although it is unclear how the supremacy of these cells for calcium-wave initiation is controlled.

Results: We describe how the loss of the mir-240/786 microRNA cluster, which results in arrhythmic defecation, causes ectopic intestinal calcium-wave initiation. mir-240/786 expression …

The Enzymes Of Biotin Dependent Co(2) Metabolism: What Structures Reveal About Their Reaction Mechanisms, Grover L. Waldrop, Hazel M. Holden, Martin St. Maurice

Biological Sciences Faculty Research and Publications

Biotin is the major cofactor involved in carbon dioxide metabolism. Indeed, biotin-dependent enzymes are ubiquitous in nature and are involved in a myriad of metabolic processes including fatty acid synthesis and gluconeogenesis. The cofactor, itself, is composed of a ureido ring, a tetrahydrothiophene ring, and a valeric acid side chain. It is the ureido ring that functions as the CO₂ carrier. A complete understanding of biotin-dependent enzymes is critically important for translational research in light of the fact that some of these enzymes serve as targets for anti-obesity agents, antibiotics, and herbicides. Prior to 1990, however, there was a …

Dpy-30 Domain And Its Flanking Sequence Mediate The Assembly Modulation Of Flagellar Radial Spoke Complexes, Radhika Gopal, Kenneth W. Foster, Pinfen Yang

Biological Sciences Faculty Research and Publications

RIIa is known as the dimerization and docking (D/D) domain of the cyclic AMP (cAMP)-dependent protein kinase. However, numerous molecules, including radial spoke protein 2 (RSP2) in Chlamydomonas flagella, also contain an RIIa or a similar DPY-30 domain. To elucidate new roles of D/D domain-containing proteins, we investigated a panel of RSP2 mutants. An RSP2 mutant had paralyzed flagella defective in RSP2 and multiple subunits near the spokehead. New transgenic strains lacking only the DPY-30 domain in RSP2 were also paralyzed. In contrast, motility was restored in strains that lacked only RSP2’s calmodulin- binding C-terminal region. These cells swam normally …

Deep Diversification And Long-Term Persistence In The South American ‘Dry Diagona’: Integrating Continent-Wide Phylogeography And Distribution Modeling Of Geckos, Fernanda P. Werneck, Tony Gamble, Guarino R. Colli, Miguel T. Rodrigues, Jack W. Sites Jr.

Biological Sciences Faculty Research and Publications

The relative influence of Neogene geomorphological events and Quaternary climatic changes as causal mechanisms on Neotropical diversification remains largely speculative, as most divergence timing inferences are based on a single locus and have limited taxonomic or geographic sampling. To investigate these influences, we use a multilocus (two mitochondrial and 11 nuclear genes) range‐wide sampling of Phyllopezus pollicaris, a gecko complex widely distributed across the poorly studied South American ‘dry diagonal’ biomes. Our approach couples traditional and model‐based phylogeography with geospatial methods, and demonstrates Miocene diversification and limited influence of Pleistocene climatic fluctuations on P. pollicaris. Phylogeographic structure and …