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

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 …

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

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.

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

Incidence And Post-Pollination Mechanisms Of Nonrandom Mating In Arabidopsis Thaliana, Rob Swanson, Ann L. Carlson, Megan Telligman

Rob Swanson

Compatible pollinations from many different taxa display nonrandom mating. Here we describe a system for examining questions of nonrandom mating in Arabidopsis thaliana. Using this system, we demonstrate that Arabidopsis thaliana displays nonrandom mating between distinct accessions. Statistical analysis of these data demonstrates aspects of both pollen competition and male–female complementarity in these matings. Cytological experiments implicate pollen germination and pollen tube growth rates as possible causal factors in these nonrandom mating efficiencies.

Life In The Slow Lane: Palmetto Seedlings Exhibit Remarkable Survival But Slow Growth In Florida's Nutrient-Poor Uplands, W. G. Abrahamson, C. R. Abrahamson

Warren G. Abrahamson, II

The palmettos Serenoa repens and Sabal etonia are crucial foundation species in many peninsular Florida vegetative associations. We monitored the survival and growth of individual palmetto seedlings using two cohorts found in different vegetative associations. Seedling cohorts containing both S. repens and S. etonia were individually tagged in 1989 and have been monitored until 2008, a period of 19 years. One cohort (N = 100 seedlings) occurs in a xeric, “inopina-phase” scrubby flatwoods and a second cohort (N =78 seedlings) lives in a well-drained, “wiregrass-phase” flatwoods. The soils at both sites are very nutrient-poor Entisols that show rapid permeability, low …

Lap3, A Novel Plant Protein Required For Pollen Development, Is Essential For Proper Exine Formation Is Essential For Proper Exine Formation, Rob Swanson, Anna A. Dobritsa, Shuh-Ichi Nishikawa, Daphne Preuss, Ewa Urbanczyk-Wochniak, Lloyd W. Sumner, Adam Hammond, Ann L. Carlson

Rob Swanson

We isolated lap3-1 and lap3-2 mutants in a screen for pollen that displays abnormal stigma binding. Unlike wild-type pollen, lap3-1 and lap3-2 pollen exine is thinner, weaker, and is missing some connections between their roof-like tectum structures. We describe the mapping and identification of LAP3 as a novel gene that contains a repetitive motif found in b-propeller enzymes. Insertion mutations in LAP3 lead to male sterility. To investigate possible roles for LAP3 in pollen development, we assayed the metabolite profile of anther tissues containing developing pollen grains and found that the lap3-2 defect leads to a broad range of metabolic …

Optimization Strategies For Electrospun Silk Fibroin Tissue Engineering Scaffolds, A. J. Meinel, Kristopher E. Kubow, E. Klotzsch, M. Garcia-Fuentes, M. L. Smith, V. Vogel, H. P. Merkle, L. Meinel

Kristopher E Kubow

No abstract provided.

Associational Resistance, Gall-Fly Preferences, And A Stem Dimorphism In Solidago Altissima, M. J. Wise, C. G. Yi, W. G. Abrahamson

Warren G. Abrahamson, II

No abstract provided.

A Public Choice Framework For Controlling Transmissable And Evolving Diseases, Ted C. Bergstrom, Carl T. Bergstrom, Ben Althouse

Ted C Bergstrom

Control measures used to limit the spread of infectious disease often generate externalities. Vaccination for transmissible diseases can re- duce the incidence of disease even among the unvaccinated, whereas antimicrobial chemotherapy can lead to the evolution of antimicro- bial resistance and thereby limit its own e#11;ectiveness over time. We integrate the economic theory of public choice with mathematical models of infectious disease to provide quantitative framework for making allocation decisions in the presence of these externalities. To illustrate, we present a series of examples: vaccination for tetanus, vaccination for measles, antibiotic treatment of otitis media, and antiviral treatment of pandemic …

Anuran Captured In Pitfall Traps In Three Agrossystem In Northwestern São Paulo State, Brazil, Rodrigo Souza Santos Rss

Rodrigo Souza Santos RSS

Although it is generally assumed that agriculture negatively influences amphibian populations, few studies on the effects of agricultural cultivations on neotropical anuran have been conducted. As a contribution to the knowledge about anuran in agriculture, the present study sought to identify the anuran species present in three different agrossystems. We used data from anurans captured in pitfall traps initially proposed for a survey of harvestmen fauna in three agrossystems (corn, soybean, and rubber tree). Four anuran species found in the pitfall traps belong to two Families: Leptodactylidae: Leptodactulus fuscus and L. mystacinus; and Leiuperidae: Eupemphix nattereri and Physalaemus cuvieri. In …

Individual Differences In Exploratory And Antipredator Behaviour In Juvenile Smallmouth Bass (Micropterus Dolomieu), Kelly L. Smith, Jeffrey Gibson Miner, Daniel D. Wiegmann, Steven P. Newman

Jeffrey Gibson Miner

The correlation of individual behaviour in different contexts, known as a behavioural syndrome, constrains the optimization of behaviour within each context. Recent studies reveal that the strength of syndromes differs amongst populations and over individual ontogeny. In this study, exploratory behaviour in an unfamiliar environment and behavioural responses to a simulated predator attack in the presence of food were measured in juvenile smallmouth bass (Micropterus dolomieu). The results revealed a syndrome: individuals who actively explored the unfamiliar environment also behaved more boldly in the presence of the model predator. The syndrome implies a tradeoff between collecting information about one's environment …

Models Of Winner And Loser Effects: A Cost-Benefit Analysis, Karlo Hock, Robert Huber

Robert Huber

Winner and loser effects, in which the probability of future success depends on individual's interaction history, help shape the structure of social hierarchies in animal groups. While reports have documented that both magnitude and symmetry of these effects vary widely across different systems, questions remain whether these effects serve to reduce the associated costs during hierarchy formation. In a series of models, cost-benefit properties of an emerging hierarchy were assessed in relation to variation in winner and loser effects. Coupling high winner effects with low loser effects resulted in an overall increase in aggressiveness in the group, increasing the costs …