Life Sciences Commons^™

Varriation Of Growth Rates In Yellow-Bellied Marmots, Carmen M. Salsbury, K. B. Armitage

Carmen M. Salsbury

Growth rates of yellow-bellied marmot (Marmota flaviventris) populations over a 32-year period (1965 -1996) varied Significantly with sex, age, location, and year. Overall, males had higher growth rates than females and young and yearlings generally had higher growth rates compared to adults at all locations. The locations varied with respect to elevation and the relationship between elevation and growth rate was complex and likely weather dependent. Low rainfall in late summer was often associated with low growth rates at high elevations where the active season is constrained and delayed by late spring snowmelt compared to low elevations. Growth rates and …

Varriation Of Growth Rates In Yellow-Bellied Marmots, Carmen M. Salsbury, K. B. Armitage

Carmen M. Salsbury

Growth rates of yellow-bellied marmot (Marmota flaviventris) populations over a 32-year period (1965 -1996) varied Significantly with sex, age, location, and year. Overall, males had higher growth rates than females and young and yearlings generally had higher growth rates compared to adults at all locations. The locations varied with respect to elevation and the relationship between elevation and growth rate was complex and likely weather dependent. Low rainfall in late summer was often associated with low growth rates at high elevations where the active season is constrained and delayed by late spring snowmelt compared to low elevations. Growth rates and …

Applications Of Natural Products In The Control Of Mosquito-Transmitted Diseases, Jesse A. Hardin, Fatimah Linda Collier Jackson

Fatimah Linda Collier Jackson

The Behavioral And Pharmacological Actions Of Nmda Receptor Antagonism Are Conserved In Zebrafish Larvae, John Chen, Roshni Patel, Theodore C. Friedman, Kevin S. Jones

Kevin Jones

Metazoan Stress Granule Assembly Is Mediated By P-Eif2alpha-Dependent And -Independent Mechanisms, Natalie Farny, Nancy Kedersha, Pamela Silver

Natalie G. Farny

Stress granules (SGs) are cytoplasmic bodies wherein translationally silenced mRNAs are recruited for triage in response to environmental stress. We report that Drosophila cells form SGs in response to arsenite and heat shock. Drosophila SGs, like mammalian SGs, are distinct from but adjacent to processing bodies (PBs, sites of mRNA silencing and decay), require polysome disassembly, and are in dynamic equilibrium with polysomes. We further examine the role of the two Drosophila eIF2alpha kinases, PEK and GCN2, in regulating SG formation in response to heat and arsenite stress. While arsenite-induced SGs are dependent upon eIF2alpha phosphorylation, primarily via PEK, heat-induced …

Ectopic T-Bet Expression Licenses Dendritic Cells For Il-12-Independent Priming Of Type 1 T Cells In Vitro, Michael Lipscomb

Michael Lipscomb

Robustness Of The Bacterial Community In The Cabbage White Butterfly Larval Midgut, Courtney Jaime Robinson, Patrick Schloss, Yolied Ramos, Kenneth F. Raffa, Jo Handelsman

Courtney Robinson

Is A Long-Chain Fatty Acid Omega-Hydroxylase Essential For Sporopollenin Synthesis In Pollen Of Arabidopsis. Plant Physiology, Rob Swanson, Anna A. Dobritsa, Jay Shrestha, Marc Morant, Franck Pinot, Michiyo Matsuno, Birger Lindberg Møller, Daphne Preuss

Rob Swanson

Sporopollenin is the major component of the outer pollen wall (exine). Fatty acid derivatives and phenolics are thought to be its monomeric building blocks, but the precise structure, biosynthetic route, and genetics of sporopollenin are poorly understood. Based on a phenotypic mutant screen in Arabidopsis (Arabidopsis thaliana), we identified a cytochrome P450, designated CYP704B1, as being essential for exine development. CYP704B1 is expressed in the developing anthers. Mutations in CYP704B1 result in impaired pollen walls that lack a normal exine layer and exhibit a characteristic striped surface, termed zebra phenotype. Heterologous expression of CYP704B1 in yeast cells demonstrated that it …

Life History, Sexual Dimorphism And 'Ornamental' Feathers In The Mesozoic Bird Confuciusornis Sanctus., Winfried S. Peters, Dieter Stefan Peters

Winfried S. Peters

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

Shaily Menon

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.

Preliminary Analysis Of The Ecology And Geography Of The Asian Nuthatches (Aves: Sittidae), Shaily Menon, Zafar-Ul Islam, Jorge Soberon, A. Townsend Peterson

Shaily Menon

We explored distributions of Asian nuthatch species in ecological and geographic space using ecological niche modeling based on occurrence data associated with specimens and observations. Nuthatches represent a well-defined clade occurring throughout the Northern Hemisphere, but are most diverse in southern Asia where 15 of the 24 species occur and where the lineage is believed to have evolved. Species richness was focused in a narrow east-west band corresponding to the forested parts of the Himalayas with a maximum number of nine species predicted present in these foci. The distributional predictions have a mid-elevation focus with highest species diversity between 1,000 …

Phospholipase Dα1 And Phosphatidic Acid Regulate Nadph Oxidase Activity And Production Of Reactive Oxygen Species In Aba-Mediated Stomatal Closure In Arabidopsis, Xuemin Wang, Yanyan Zhang, Huiying Zhu, Qun Zhang, Maoyin Li, Min Yan, Rong Wang, Liling Wang, Ruth Welti, Wenhua Zhang

Xuemin (Sam) Wang

Spider Silk As A Novel High Performance Biomimetic Muscle Driven By Humidity, Ingi Agnarsson, Ali Dhinojwala, Vasav Sahni, Todd Blackledge

Todd A. Blackledge

The abrupt halt of a bumble bee's flight when it impacts the almost invisible threads of an orb web provides an elegant example of the amazing strength and toughness of spider silk. Spiders depend upon these properties for survival, yet the impressive performance of silk is not limited solely to tensile mechanics. Here, we show that silk also exhibits powerful cyclic contractions, allowing it to act as a high performance mimic of biological muscles. These contractions are actuated by changes in humidity alone and repeatedly generate work 50 times greater than the equivalent mass of human muscle. Although we demonstrate …

How Super Is Supercontraction? Persistent Versus Cyclic Responses To Humidity In Spider Dragline Silk, Todd Blackledge, Cecilia Boutry, Shing-Chung Wong, Avinash Baji

Todd A. Blackledge

Spider dragline silk has enormous potential for the development of biomimetic fibers that combine strength and elasticity in low density polymers. These applications necessitate understanding how silk reacts to different environmental conditions. For instance, spider dragline silk 'supercontracts' in high humidity. During supercontraction, unrestrained dragline silk contracts up to 50% of its original length and restrained fibers generate substantial stress. Here we characterize the response of dragline silk to changes in humidity before, during and after supercontraction. Our findings demonstrate that dragline silk exhibits two qualitatively different responses to humidity. First, silk undergoes a previously unknown cyclic relaxation-contraction response to …

Was Climate The Prime Releaser For Encephalization? An Editorial Comment, David Schwartzman, George Middendorf, Miranda Armour-Chelu

George Middendorf

How Super Is Supercontraction? Persistent Versus Cyclic Responses To Humidity In Spider Dragline Silk, Todd A. Blackledge, Cecilia Boutry, Shing-Chung Wong, Avinash Baji

Dr. Shing-Chung Josh Wong

Spider dragline silk has enormous potential for the development of biomimetic fibers that combine strength and elasticity in low density polymers. These applications necessitate understanding how silk reacts to different environmental conditions. For instance, spider dragline silk 'supercontracts' in high humidity. During supercontraction, unrestrained dragline silk contracts up to 50% of its original length and restrained fibers generate substantial stress. Here we characterize the response of dragline silk to changes in humidity before, during and after supercontraction. Our findings demonstrate that dragline silk exhibits two qualitatively different responses to humidity. First, silk undergoes a previously unknown cyclic relaxation-contraction response to …

Spider Silk As A Novel High Performance Biomimetic Muscle Driven By Humidity, Ingi Agnarsson, Ali Dhinojwala, Vasav Sahni, Todd A. Blackledge

Ali Dhinojwala

The abrupt halt of a bumble bee's flight when it impacts the almost invisible threads of an orb web provides an elegant example of the amazing strength and toughness of spider silk. Spiders depend upon these properties for survival, yet the impressive performance of silk is not limited solely to tensile mechanics. Here, we show that silk also exhibits powerful cyclic contractions, allowing it to act as a high performance mimic of biological muscles. These contractions are actuated by changes in humidity alone and repeatedly generate work 50 times greater than the equivalent mass of human muscle. Although we demonstrate …

Allometry Of The Duration Of Flight Feather Molt In Birds, Sievert Rohwer, Robert E. Ricklefs, Vanya G. Rohwer, Michelle M. Copple

Robert Ricklefs

No abstract provided.

Treatment Options For Hepatitis C And The Rationale For Low Response Rates In African Americans, Cheu Patricia Manka, Ralph Gomes, Rebecca Reviere, Clarence Lee

Clarence Lee

Two New Species Of Cave-Dwelling Beetles Trechus Clairville Of Fulvus-Group In Portugal, Ana Reboleira, Fernando Gonçalves, Artur Serrano

Ana Sofia P.S. Reboleira

Two new cave-dwelling ground beetle species, Trechus gamae sp. n. and Trechus lunai sp. n., from Portugal, are described. The new species are included in the Trechus fulvus-group by their morphological characters. The work provides diagnostic characters in particular those of the structure of male genitalia, and the distribution of the hypogean species of the fulvus -group at the Estremenho Karstic Massif is mapped. Some comments on the seasonal activity of T. gamae sp. n. are also given. An identification key to the males of the T. fulvus-group species from the Estremenho Karstic Massif is presented, and biogeographical comments are …

A Conserved Ccch-Type Zinc Finger Protein Regulates Mrna Nuclear Adenylation And Export, Natalie Farny, Jessica Hurt, Robert Obar, Steven Gygi, Pamela Silver, Bo Zhai

Natalie G. Farny

Coupling of messenger RNA (mRNA) nuclear export with prior processing steps aids in the fidelity and efficiency of mRNA transport to the cytoplasm. In this study, we show that the processes of export and polyadenylation are coupled via the Drosophila melanogaster CCCH-type zinc finger protein CG6694/dZC3H3 through both physical and functional interactions. We show that depletion of dZC3H3 from S2R+ cells results in transcript hyperadenylation. Using targeted coimmunoprecipitation and liquid chromatography mass spectrometry (MS)/MS techniques, we characterize interactions of known components of the mRNA nuclear export and polyadenylation machineries with dZC3H3. Furthermore, we demonstrate the functional conservation of this factor, …

Genetic Change Following Fire In Populations Of A Seed-Banking Perennial Plant, Rebecca W. Dolan, Pedro F. Quintana-Ascencio, Eric S. Menges

Rebecca W. Dolan

Disturbances such as fire have the potential to remove genetic variation, but seed banks may counter this loss by restoring alleles through a reservoir effect. We used allozyme analysis to characterize genetic change in two populations of the perennial Hypericum cumulicola, an endemic of the fire-prone Florida scrub. We assessed genetic variation before and 1, 2, and 3 years after fire that killed nearly all aboveground plants. Populations increased in size following fire, with most seedlings likely recruited from a persistent seed bank. Four of five loci were variable. Most alleles were present in low frequencies, but our large sample …

A New Species Of Streptanthus (Brassicaceae) From Three Peaks In Lake County, California, Rebecca W. Dolan, Richard O'Donnell

Rebecca W. Dolan

Streptanlhus vernalis is a newly described species inhabiting serpentine rock outcrops in the Three Peaks area in Lake County, California. Morphological and allozyme data indicate that this taxon is related to the S. morrisonii complex.

Defining Behavioral And Molecular Differences Between Summer And Migratory Monarch Butterflies, Robert Gegear, Haisun Zhu, Amy Casselman, Sriramana Kanginakudru, Steven Reppert

Robert J. Gegear

Background: In the fall, Eastern North American monarch butterflies (Danaus plexippus) undergo a magnificent long-range migration. In contrast to spring and summer butterflies, fall migrants are juvenile hormone deficient, which leads to reproductive arrest and increased longevity. Migrants also use a time-compensated sun compass to help them navigate in the south/southwesterly direction en route for Mexico. Central issues in this area are defining the relationship between juvenile hormone status and oriented flight, critical features that differentiate summer monarchs from fall migrants, and identifying molecular correlates of behavioral state. Results: Here we show that increasing juvenile hormone activity to induce summer-like …

The Value Of A Net‐Cage As A Fish Aggregating Device In Southern California, Daniel Pondella

Daniel Pondella

There is an urgent need for primary data that can be used to quantify the value of marine aquaculture facilities that also describe influences on the surrounding natural ecosystem and its wild fish communities. Divers completed 360 transect replicates below a net-cage and at nearby and distant rocky reefs off Catalina Island, California, estimating the species abundance and size class of all conspicuous fishes in the water column. We observed 10,234 fishes aggregating below the net-cage with a mean annual density of 142 (SE ± 30) per 100 m2 and diversity H′ 2.29. At the adjacent reference reef, we counted …

Drosophila Nanoparticle Toxicity Model, Mark Nielsen

Mark G. Nielsen

Department of Defense Consortium Research Fellows Program, $120,000 (2009-2012). Research Assistantship funding for my Ph.D. student Ryan Posgai, who developed the Drosophila nanoparticle toxicity model

Structural Implications Of Succulence: Architecture, Anatomy, And Mechanics Of Photosynthetic Stem Succulents, Pachycauls, And Leaf Succulents, Gretchen North, E. Bobich

Gretchen North

No abstract provided.

Behavioural, Ecological And Genetic Evidence Confirm The Occurrence Of Host-Associated Differentiation In Goldenrod Gall Midges, Warren Abrahamson, N. Dorchin, S.D. Jordan, E.R. Scott, C.E. Clarkin, M.P. Luongo

Warren G. Abrahamson, II

No abstract provided.

Inheritance Of Shoulder Spotting In The Tetra, Hyphessobrycon Bentosi Characidae, Jack Frankel

Jack Frankel

Contributions Of Gut Bacteria To Bacillus Thuringiensis-Induced Mortality Vary Across A Range Of Lepidoptera, Nichole A. Broderick, Courtney Jaime Robinson, Matthew D. Mcmahon, Kenneth F. Raffa

Courtney Robinson