Life Sciences Commons^™

Drosophila Fascin Mutants Are Rescued By Overexpression Of The Villin-Like Protein, Quail, Kelly Cant, Brenda A. Knowles, Shalina Mahajan-Miklos, Matthew Heintzelman, Lynn Cooley

Dartmouth Scholarship

Actin bundle assembly in specialized structures such as microvilli on intestinal epithelia and Drosophila bristles requires two actin bundling proteins. In these systems, the distinct biochemical properties and temporal localization of actin bundling proteins suggest that these proteins are not redundant. During Drosophila oogenesis, the formation of cytoplasmic actin bundles in nurse cells requires two actin bundling proteins, fascin encoded by the singed gene and a villin-like protein encoded by the quail gene. singed and quail mutations are fully recessive and each mutation disrupts nurse cell cytoplasmic actin bundle formation. We used P-element mediated germline transformation to overexpress quail in …

Sex Can Be Dangerous: Acoustically-Orienting Parasitoids On Field Crickets (Orthoptera: Gryllidae), Gita R. Kolluru

Biological Sciences

The Orthopterists' Society generously awarded me grants in 1995 and 1997 to conduct research on Teleogryllus oceanicus (Orthoptera: Gryllidae) on the Big Island of Hawaii. Here I report results to date from fieldwork conducted in the past few years.

Exploitations Of Sexual Signals By Predators And Parasitoids, Marlene Zuk, Gita R. Kolluru

Biological Sciences

Signals used to attract mates are often conspicuous to predators and parasites, and their evolution via sexual selection is expected to be opposed by viability selection. Many secondary sexual traits may represent a compromise between attractiveness and avoidance of detection. Although such signal exploitation appears to be widespread, most examples come from species that use acoustic or olfactory mating signals, and relatively few cases of visual signal exploitation can be substantiated. Because males are usually the signaling sex, they are more at risk from predators or parasitoids that locate prey or hosts by sexual signals; this differential selection on the …

Bulletin No. 36: Amphibians And Reptiles Of The Connecticut College Arboretum, Jill Devito, Joseph Markow

Bulletins

No abstract provided.

New Caribbean Locality For The Extinct Great White Shark Carcharodon, Clare Flemming, Donald A. Mcfarlane

WM Keck Science Faculty Papers

Carcharodon is represented by a single upper tooth (Fig. 1) which we extracted from the eroding Pliocene limestone wall, some six meters above the floor at the northern end of Darby Sink. Much of the tooth is missing, but the remaining portion includes features diagnostic of this genus. The tooth conforms in size and morphology to Carcharodon megalodon (Agassiz, 1843), an extinct great white shark.

A Second Pre-Wisconsinan Locality For The Extinct Jamaican Rodent, Clidomys (Rodentia: Heptaxodontidae), Donald A. Mcfarlane, Joyce Lundberg, Clare Flemming, Ross D. E. Macphee, Stein-Erik Lauritzen

WM Keck Science Faculty Papers

Clidomys is the most distinctive but least well known member of the late Quaternary terrestrial mammal fauna of Jamaica. Here we report the second dated locality for this genus. The Illinoisan age we report further strengthens arguments we have made elsewhere, that Clidomys represents an early - probably pre-Wisconsinan - extinction that contrasts with the growing record of Holocene extinctions in the Antilles.

Ecological Effects Of Major Storms On Coastal Watersheds And Coastal Waters: Hurricane Bob On Cape Cod, I. Valiela, P. Peckol, C. D'Avanzo, J. Kremer, D. Hersh, K. Foreman, K. Lajtha, B. Seely, W. R. Geyer, T. Isaji, R. Crawford

Biological Sciences: Faculty Publications

Hurricane Bob, a category 3 storm, made landfall on Cape Cod in August 1991, and its effects on watersheds and adjoining estuaries were detected in the ongoing studies being caried out as part of the Waquoit Bay Land Margin Ecosystems Research project. On land, Bob had only minor overall effects on forests; localized wind bursts did snap and break trees in small and widely scattered forest parcels. Wind stripped up to half the leaves of deciduous trees and many herbaceous plants on the watershed, and most remaining leaves were damaged by salt, so that by the end of Aug, Cape …

Photosynthetic Parameters And Empirical Modeling Of Primary Production: A Case Study On The Antarctic Peninsula Shelf, Mark A. Moline, Oscar Schofield, Nicolas P. Boucher

Biological Sciences

Eight hundred photosynthesis-irradiance relationships were determined in the shelf waters adjacent to Palmer Station, Antarctica during the spring/summer periods of 1991–94. Biomass specific maximum photosynthetic rate, P^B_max, and the light limited photosynthetic efficiency, α^B, were poorly correlated to the physical forcing and nutrient regimes at the sampling stations. The two photosynthetic parameters, however, did strongly covary indicating the minimum irradiance required to saturate photosynthesis, I^k, was relatively constant in this highly variable environment. The variability in I^k could partially be attributed to both depth in the water column and time of the …

Structure Of The Protein Kinase Cβ Phospholipid-Binding C2 Domain Complexed With Ca2+, R. Bryan Sutton, Stephen R. Sprang

Biological Sciences Faculty Publications

Background: Conventional isoforms (α, β and γ) of protein kinase C (PKC) are synergistically activated by phosphatidylserine and Ca²⁺; both bind to C2 domains located within the PKC amino-terminal regulatory regions. C2 domains contain a bipartite or tripartite Ca²⁺-binding site formed by opposing loops at one end of the protein. Neither the structural basis for cooperativity between phosphatidylserine and Ca²⁺, nor the binding site for phosphatidylserine are known. Results: The structure of the C2 domain from PKCβ complexed with Ca²⁺ and o-phospho-L-serine has been determined to 2.7 Å resolution using X-ray crystallography. The …

Ecosystem Metabolism In A Subtropical Seagrass-Dominated Lagoon, Susan Ziegler, Ronald Benner

Faculty Publications

Measurements of ecosystem gross primary production (GPP) and respiration (R) were made for 2 to 3 consecutive days on 10 occasions from February 1996 through June 1997 in the seagrass-dominated Laguna Madre (Texas, USA). Ecosystem GPP and R were quantified using 3 independent measurements including the open-water technique using dissolved oxygen (DO) and dissolved inorganic carbon (DIC) and the summation of discrete measurements of the water column and benthos. Diel curves of DIC were often influenced by water movement while the impact of water movement on DO was not apparent. This was attributed to the longer turnover time of DIC …

Comparative Reproductive Biology Of Two Florida Pawpaws Asimina Reticulata Chapman And Asimina Tetramera Small, Anne Cheney Cox

FIU Electronic Theses and Dissertations

I investigated the phenology and breeding systems of two Florida endemic pawpaws, Asimina reticulata, widespread in peninsular Florida, and A. tetramera, a federally endangered species limited to two counties on the Atlantic Coastal Ridge. The purpose of this study was to determine if differences contribute to the rarity of Asimina tetramera compared with A. reticulata. The study was conducted in sand pine scrub sites with the largest populations of A. tetramera in the two counties. Flowering seasons differ for the two species. Both species are hermaphroditic and strongly protogynous. Pollination experiments show that neither species is autogamous and the primary …

Rostral-Caudal Variation In Troponin T And Parvalbumin Correlates With Differences In Relaxation Rates Of Cod Axial Muscle, Tierney M. Thys, Jason M. Blank, Fred H. Schachat

Biological Sciences

Relaxation rate is an important determinant of axial muscle power production during the oscillatory contractions of undulatory locomotion. Recently, significant differences have been reported in the relaxation rates of rostral versus caudal white muscle fibers of the Atlantic cod Gadus morhua L. The present study investigates the biochemical correlates of this rostral-caudal physiological variation. Using denaturing gel electrophoresis, a series of fresh muscle samples from the dorsal epaxial muscle region was analyzed and several differences were detected. First, a gradual shift occurs in the expression of two troponin T isoforms along the length of the body. Second, rostral muscles were …

Metamorphis Is Not A New Beginning, Jan A. Pechenik, Dean E. Wendt, Jeremiah N. Jarrett

Biological Sciences

No abstract provided.

Sequence Analysis Of Bacterial Dna In The Colon Of An Andean Mummy, Massimo Ubaldi, Stefania Luciani, Isolina Marota, Gino Fornaciari, Raul J. Cano, Franco Rollo

Biological Sciences

We have isolated DNA from 14 tissue samples from the internal organs of an Andean human mummy (10th–11th century A.D.) and have checked the persistence of the original human and bacterial templates using the following main approaches: 1) amino acid racemization test; 2) quantification of mitochondrial DNA copy number; 3) survey of bacterial DNA in the different organs; 4) sequence analysis of bacterial amplicons of different lengths. The results demonstrate that both the original human DNA and the DNA of the bacteria of the mummy gut are preserved. In particular, sequence analysis of two (respectively 100 and 196 bp in …

Testosterone Effects On Renal Norepinephrine Content And Release In Rats With Different Y Chromosomes, Thomas J. Jones, Gail Dunphy, Amy Milsted, Daniel Ely

Biology Faculty Research

The Y chromosome in spontaneously hypertensive rats (SHR) and stroke-prone rats has been shown to contain a locus that contributes to the hypertensive effect; both the sympathetic nervous system and testosterone may be involved. The objective of this study was to look at the effects of testosterone on renal norepinephrine (NE) release and content in the isolated perfused kidney in different Y chromosome backgrounds. The study involved male SHR, Wistar-Kyoto rats (WKY), and 2 consomic strains with different Y chromosomes (n=5 to 8 per group). Adult animals were castrated, and implants containing testosterone propionate were placed at the base of …

Responses Of Mole Salamanders To Clearcutting: Using Field Experiments In Forest Management, Anne C. Chazal, Peter H. Niewiarowski

Biology Faculty Research

Impacts of forest management practices on amphibian populations have received growing attention in the last 10 yr. However, to date, measured responses include only comparisons of species diversity indices and population counts without true spatial and temporal controls. We used an experimental approach to test for differences in growth rate, fecundity, age at maturity, and whole-body storage lipids in individual mole salamanders, Ambystoma talpoideum, placed in differently managed habitats. Four 100-m(2) field enclosures were built in each of two habitats, a 4-mo-old clearcut and an adjacent 40-yr-old pine forest. On 19 July 1994, 80 recently metamorphosed and individually marked, weighed, …

Effect Of Activity On Energy Allocation In The Northern Abalone, Haliotis Kamtschatkana (Jonas), Deborah A. Donovan, Thomas H. Carefoot

Biology Faculty and Staff Publications

The effect of activity, in the form of increased respiratory energy expenditure and secretion of mucus, on the summer and winter energy budgets of Haliotis kamtschatkana was assessed. Abalone exhibited seasonal variations in field activity with 20% of all individuals observed crawling during June to October, compared with -1 quiescent 12.0 h day^-1 alert. O.7 h day^-1 feeding, and 1.5 h day^-1 crawling during the summer, and 15.8 h day^-1 quiescent, 5.5 h day^-1 alert, 2.3 h day^-1 feeding, and o.4 h day^-1 crawling during the winter. Videotapes of abalone made over 24-h …

Hsp70 And Larval Thermotolerance In Drosophila Melanogaster: How Much Is Enough And When Is More Too Much?, Robert A. Krebs, Martin E. Feder

Biological, Geological, and Environmental Faculty Publications

Heat shock proteins (Hsps) and other molecular chaperones perform diverse cellular roles (e.g., inducible thermotolerance) whose functional consequences are concentration dependent. We manipulated Hsp70 concentration quantitatively in intact larvae of Drosophila melanogaster to examine its effect on survival, developmental time and tissue damage after heat shock. Larvae of an extra-copy strain, which has 22 hsp70 copies, produced Hsp70 more rapidly and to higher concentrations than larvae of a control strain, which has the wild-type 10 copies of the gene. Increasing the magnitude and duration of pretreatment increased Hsp70 concentrations, improved tolerance of more severe stress, and reduced delays in development. …

Characterization Of Sequences Associated With Position-Effect Variegation At Pericentric Sites In Drosophila Heterochromatin, D Cryderman, M Cuaycong, Sarah C.R. Elgin, L Wallrath

Biology Faculty Publications & Presentations

In a variety of organisms, euchromatic genes brought into juxtaposition with pericentric heterochromatin show position-effect variegation (PEV), a silencing of gene expression in a subset of the cells in which the gene is normally expressed. Previously, a P-element mobilization screen identified transgenic Drosophila stocks showing PEV of an hsp70-white+ reporter gene; transgenes in many of these stocks map to the chromocenter of polytene chromosome. A screen at an elevated temperature identified two stocks that under standard culture temperatures show complete repression of the hsp70-white+ transgene. The transgenes in both cases map to the chromocenter of polytene chromosomes. Different types of …

Deforestation In The Tropics: Reconciling Disparities In Estimates For India, Shaily Menon, Kamaljit S. Bawa

Peer Reviewed Publications

Here we examine recent disparate estimates of deforestation obtained for India. We discuss the sources of disparity and the implications of inaccurate estimates and suggest ways in which future attempts at estimating deforestation might reconcile the disparity. Despite the importance of deforestation and its consequences, no attempt has been made to reconcile the different estimates obtained for India.

Mutations In Bartonella Bacilliformis Gyrb Confer Resistance To Coumermycin A(1), James M. Battisti, Laura A. Smitherman, D. Scott Samuels, Michael F. Minnick

Biological Sciences Faculty Publications

This study describes the first isolation and characterization of spontaneous mutants conferring natural resistance to an antibiotic for any Bartonella species. The Bartonella bacilliformis gyrB gene, which encodes the B subunit of DNA gyrase, was cloned and sequenced. The gyrB open reading frame (ORF) is 2,079 bp and encodes a deduced amino acid sequence of 692 residues, corresponding to a predicted protein of similar to 77.5 kDa. Sequence alignment indicates that B. bacilliformis GyrB is most similar to the GyrB protein from Bacillus subtilis (40.1% amino acid sequence identity) and that it contains the longest N-terminal tail (52 residues) of …

Force-Velocity-Power And Force-Pca Relationships Of Human Soleus Fibers After 17 Days Of Bed Rest, Jeffrey J. Widrick, Kris M. Norenberg, C. A. Blaser, M. Karhanek, Jennifer J. Sherwood, Scott W. Trappe, Todd A. Trappe, David L. Costill, Robert H. Fitts

Biological Sciences Faculty Research and Publications

Soleus muscle fibers from the rat display a reduction in peak power and Ca²⁺ sensitivity after hindlimb suspension. To examine human responses to non-weight bearing, we obtained soleus biopsies from eight adult men before and immediately after 17 days of bed rest (BR). Single chemically skinned fibers were mounted between a force transducer and a servo-controlled position motor and activated with maximal (isotonic properties) and/or submaximal (Ca²⁺ sensitivity) levels of free Ca²⁺. Gel electrophoresis indicated that all pre- and post-BR fibers expressed type I myosin heavy chain. Post-BR fibers obtained from one subject displayed increases in …

Invasion Of The Nucleotide Snatchers, Stephen R. Sprang, David E. Coleman

Biological Sciences Faculty Publications

Although the mechanics differ, GEFs appear to deform their substrates in similar ways. In all cases, switch I is pulled away from switch II and the P loop, exposing the active site; dislocation of switch I also displaces a Mg²⁺-binding residue, but this in itself should have little affect on GDP affinity. GEFs also restructure and displace the amino terminus of switch II and consequently dismantle the χ-phosphate-binding site, at the same time moving a conserved aspartate residue that serves as a water-mediated Mg²⁺ ligand. Residues, either from the GEF or the G protein, are positioned to …

Transport Of Er Vesicles On Actin Filaments In Neurons By Myosin V, George M. Langford, Joel S. Tabb, Bradley J. Molyneaux, Darien L. Cohen, Sergei A. Kuznetsov

Biology - All Scholarship

Axoplasmic organelles in the giant axon of the squid have been shown to move on both actin filaments and microtubules and to switch between actin filaments and microtubules during fast axonal transport. The objectives of this investigation were to identify the specific classes of axoplasmic organelles that move on actin filaments and the myosin motors involved. We developed a procedure to isolate endoplasmic reticulum (ER) from extruded axoplasm and to reconstitute its movement in vitro. The isolated ER vesicles moved on exogenous actin filaments adsorbed to coverslips in an ATP-dependent manner without the addition of soluble factors. Therefore myosin was …

Transport Of Er Vesicles On Actin Filaments In Neurons By Myosin V, Joel S. Tabb, Bradley J. Molyneaux, Darien L. Cohen, Sergei A. Kuznetsov, George M. Langford

Dartmouth Scholarship

Axoplasmic organelles in the giant axon of the squid have been shown to move on both actin filaments and microtubules and to switch between actin filaments and microtubules during fast axonal transport. The objectives of this investigation were to identify the specific classes of axoplasmic organelles that move on actin filaments and the myosin motors involved. We developed a procedure to isolate endoplasmic reticulum (ER) from extruded axoplasm and to reconstitute its movement in vitro. The isolated ER vesicles moved on exogenous actin filaments adsorbed to coverslips in an ATP-dependent manner without the addition of soluble factors. Therefore myosin was …

Identification Of A G(Iα) Binding Site On Type V Adenylyl Cyclase, Carmen W. Dessauer, John J.G. Tesmer, Stephen R. Sprang, Alfred G. Gilman

Biological Sciences Faculty Publications

The stimulatory G protein α subunit G(sα) binds within a cleft in adenylyl cyclase formed by the α1-α2 and α3-β4 loops of the C₂ domain. The pseudosymmetry of the C₁ and C₂ domains of adenylyl cyclase suggests that the homologous inhibitory α subunit G(iα) could bind to the analogous cleft within C₁. We demonstrate that myristoylated guanosine 5'-3-O- (thio)triphosphate-G(iα1) forms a stable complex with the C₁ (but not the C₂) domain of type V adenylyl cyclase. Mutagenesis of the membrane-bound enzyme identified residues whose alteration either increased or substantially decreased the IC …

Effect Of Larval Swimming Duration On Growth And Reproduction Of Bugula Neritina (Bryozoa) Under Field Conditions, Dean E. Wendt

Biological Sciences

A growing body of evidence indicates that even subtle events occurring during one portion of an animal's life cycle can have detrimental, and in some cases, lasting effects on later stages. Using a laboratory-field transplant design, postmetamorphic costs associated with the duration of larval swimming were investigated in the bryozoan Bugula neritina. Larvae were induced to metamorphose in the laboratory after swimming for either less than 1 h or between 23 and 24 h; colonies that developed from these two groups of larvae are referred to hereafter as "1-h colonies" and "24-h colonies," respectively. After completing metamorphosis, individuals were …

Asymmetrical Force Production In The Maneuvering Flight Of Pigeons, Douglas R. Warrick, Kenneth P. Dial, Andrew A. Biewener

Biological Sciences Faculty Publications

Downstroke force produced by Rock Doves (Columba livia) as they negotiated an obstacle course was measured using in vivo recordings of delto-pectoral crest strain. During this slow $(<6\ {\rm m}\ {\rm s}^{-1})$ , maneuvering flight, pigeons produced a series of four to six successive wingbeats in which the wing on the outside of the turn produced greater peak force than the wing on the inside of the turn, suggesting that the birds maneuvered in a saltatory manner during slow flight. This asymmetrical downstroke force may be used to increase or reestablish bank lost during upstroke, or it may be directed as thrust to compensate for adverse yaw or create excess yaw to alter the bird's direction of flight. Continuous production of asymmetrical downstroke force through a turn differs from the traditional model of maneuvering flight, in which asymmetrical force is used only to initiate a bank, the forces are briefly reversed to arrest the momentum of the roll and then equalized to maintain the established bank, and the redirected lift of the wings then effects a turn. Although this traditional model probably describes most turns initiated during fast and gliding flight in birds, it underestimates the complexity of maneuvering during slow, flapping flight, where sophisticated kinematics and neuromuscular control are needed to change direction effectively.

Increased Photosynthesis Offsets Costs Of Allocation To Sapwood In An Arid Environment, Eileen V. Carey, Ragan M. Callaway, Evan H. Delucia

Biological Sciences Faculty Publications

We assessed the effect that varying patterns of biomass allocation had on growth of ponderosa pine (Pinus ponderosa) growing in the desert climate of the Great Basin and the montane climate of the eastern Sierra Nevada. Prior work established that desert trees have lower leaf:sapwood area ratios than montane trees (0.104 and 0.201 m²/cm², respectively) and proportionally greater stem respiration. Sapwood:leaf mass ratios are also greater and increase more as a function stem diameter in desert than in montane trees. We hypothesized that this increased allocation of carbon to stem sapwood and stem respiration …

Grizzly Bear Digging: Effects On Subalpine Meadow Plants In Relation To Mineral Nitrogen Availability, Sandra E. Tardiff, Jack Arthur Stanford

Biological Sciences Faculty Publications

Grizzly bears (Ursus arctos horribilis) affect plant distributions and mineral nitrogen availability when they forage by digging for the bulbs of glacier lilies (Erythronium grandiflorum) growing in subalpine meadows of Glacier National Park, Montana, United States. Our working hypothesis is that grizzly bears structure plant communities and influence nitrogen availability when they selectively dig for preferred plants. In this paper, we report on differences found in recently disturbed digs (<5 yr old) when compared to adjacent, undisturbed meadow.

We used ion exchange resin bags to determine the availability of mineral nitrogen in grizzly bear digs compared to undisturbed meadow. Soil in digs contained significantly …