Biology Commons^™

Heat-Shock Protein 70 (Hsp70) As A Biochemical Stress Indicator: An Experimental Field Test In Two Congeneric Intertidal Gastropods (Genus: Tegula), Lars Tomanek, Eric Sanford

Biological Sciences

Although previous studies have demonstrated that heat-shock protein 70 (Hsp70) can be induced by environmental stress, little is known about natural variation in this response over short time scales. We examined how Hsp70 levels varied over days to weeks in two intertidal snail species of the genus Tegula. Sampling was conducted both under naturally changing environmental conditions and in different vertical zones on a rocky shore. The subtidal to low-intertidal T. brunnea was transplanted into shaded and unshaded mid-intertidal cages to assess temporal variation in Hsps under conditions of increased stress. For comparison, the low to mid-intertidal ,T. …

Continuous Hyperspectral Absorption Measurements Of Colored Dissolved Organic Material In Aquatic Systems, Gary J. Kirkpatrick, Cristina Orrico, Mark A. Moline, Matthew Oliver, Oscar M. Schofield

Biological Sciences

The majority of organic carbon in the oceans is present as dissolved organic matter (DOM); therefore understanding the distribution and dynamics of DOM is central to understanding global carbon cycles. Describing the time-space variability in colored dissolved organic matter (CDOM) has been difficult, as standard spectrophotometric methods for CDOM determination are laborious and susceptible to methodological biases. Previously, measurements of CDOM absorption in discrete water samples by use of a liquid-waveguide capillary cell (LWCC) compared favorably with measurements made with a benchtop spectrophotometer. Given this, we focused on automating the LWCC technique to improve our spatial and temporal sampling capabilities …

Complex Co-Substrate Addition Increases Initial Petroleum Degradation Rates During Land Treatment By Altering Bacterial Community Physiology, Christopher W, Kaplan, Brian G. Clement, Alice Hamrick, Robert W. Pease, Carl Flint, Raul J. Cano, Christopher L. Kits

Biological Sciences

A pilot-scale land treatment unit (LTU) was constructed at the former Guadalupe oil production field with the purpose of investigating the effect of co-substrate addition on the bacterial community and the resulting rate and extent of total petroleum hydrocarbon (TPH) degradation. The TPH was a weathered mid-cut distillate (C10-C32) excavated from the subsurface and stockpiled before treatment. A control cell (Cell 1) in the LTU was amended with nitrogen and phosphorus while the experimental cell (Cell 2) was amended with additional complex co-substrate—corn steep liquor. During the pilot LTU operation, measurements were taken of TPH, nutrients, moisture, aerobic heterotrophic bacteria …

Chromosome-Wide Control Of Meiotic Crossing Over In C. Elegans, Kenneth J. Hillers, Anne M. Villeneuve

Biological Sciences

A central event in sexual reproduction is the reduction in chromosome number that occurs at the meiosis I division. Most eukaryotes rely on crossing over between homologs, and the resulting chiasmata, to direct meiosis I chromosome segregation, yet make very few crossovers per chromosome pair [1] and [2]. This indicates that meiotic recombination must be tightly regulated to ensure that each chromosome pair enjoys the crossover necessary to ensure correct segregation. Here, we investigate control of meiotic crossing over in Caenorhabditis elegans, which averages only one crossover per chromosome pair per meiosis [3] and [4], by constructing genetic maps …

Characterization Of Six Polymorphic Microsatellites For The Polychaete Tubeworm Hydroides Elegans And Cross-Species Amplification In The Congener Hydroides Hexagonus, J. B. Pettengill, M. G. Hadfield, M. D. Schug, D. E. Wendt

Biological Sciences

We isolated and characterized six polymorphic microsatellite loci for the polychaete tubeworm, Hydroides elegans. Two additional loci were not reliably scorable and estimates of heterozygosity were obtained for the other six. In addition, cross-species amplification was successful for two loci using the congener H. hexagonus. Given that few microsatellite loci are available for polychaetes, these markers will be useful in assessing dispersal and gene flow in H. elegans and probably also other polychaetes.

Phenotype Management: A New Approach To Habitat Restoration, Jason V. Watters, Sean C. Lema, Gabrielle A. Nevitt

Biological Sciences

The goal of habitat restoration is to provide environmental conditions that promote the maintenance and growth of target populations. But rarely is it considered how the allocation of resources influences the diversity of phenotypes in these populations. Here we present a framework for considering how habitat restoration can shape the development and expression of phenotypes. We call this approach phenotype management as it entails restoring the resources in a habitat to manage phenotypic diversity. Phenotype management is achieved by manipulating the spatial and temporal distribution of resources to alter the degree of competition among individuals. Differences in competition, in turn, …

Functional And Comparative Genomic Analyses Of An Operon Involved In Fructooligosaccharide Utilization By Lactobacillus Acidophilus, Rodolphe Barrangou, Eric Altermann, Robert Hutkins, Raul J. Cano, Todd Klaenhammer

Biological Sciences

Lactobacillus acidophilus is a probiotic organism that displays the ability to use prebiotic compounds such as fructooligosaccharides (FOS), which stimulate the growth of beneficial commensals in the gastrointestinal tract. However, little is known about the mechanisms and genes involved in FOS utilization by Lactobacillus species. Analysis of the L. acidophilus NCFM genome revealed an msm locus composed of a transcriptional regulator of the LacI family, a four-component ATP-binding cassette (ABC) transport system, a fructosidase, and a sucrose phosphorylase. Transcriptional analysis of this operon demonstrated that gene expression was induced by sucrose and FOS but not by glucose or fructose, …

Variation Between Observed And True Terminal Restriction Fragment Length Is Dependent On True Trf Length And Purine Content, Christopher W. Kaplan, Christopher L. Kitts

Biological Sciences

Terminal Restriction Fragment (TRF) pattern analysis has become a widely used and informative tool for studying microbial communities. Variation between sequence-determined or true TRF length and observed TRF length (TRF drift) has been previously reported and can significantly affect identification of bacterial species using TRF lengths predicted from sequence databases. In this study TRF drift was determined for 21 bacterial species using an ABI 310 Genetic Analyzer. TRF drift was positively correlated with true TRF length and negatively correlated with TRF purine content. This implies that subtle differences in molecular weight, whether from purine content or dye label, can significantly …

A Pcr Assay For Specific Detection Of The Pandemic Vibrio Parahaemolyticus O3:K6 Clone From Shellfish, P.S. Marie Yeung, A. Depaola, C. A. Kaysner, K. J. Boor

Biological Sciences

The current standard method for identifying Vibrio parahaemolyticus serotype O3:K6, an emerging pathogen with apparent enhanced virulence characteristics, typically takes 4 to 6 d to complete and requires serotyping. To provide a more rapid strategy, we optimized a polymerase chain reaction (PCR)-based assay for specific detection of V. parahaemolyticus O3:K6. Of 78 V. parahaemolyticus isolates and other related species; only strains classified into the V. parahaemolyticus O3:K6 clonal group (n = 39) showed positive results in the PCR assay. The assay detected 2.3 cells/PCR reaction and 310 cells/g using bacterial cultures and inoculated oyster samples, respectively. Sensitive and specific detection …

Adaptive Differentiation In Response To Water Stress By Edaphic Races Of Lasthenia Californica (Asteraceae), Nishanta Rajakaruna, Gary E. Bradfield, Bruce A. Bohm, Jeanette Whitton

Biological Sciences

Two edaphic races of Lasthenia californica sensu Ornduff (races A and C) grow in parapatry on a serpentine outcrop at Jasper Ridge Biological Preserve, California. The races occupy distinct edaphic habitats that have different water‐holding capacities. We predict that the two races will show differentiation in reproductive strategies related to their response to water stress. In order to test this hypothesis, we performed a greenhouse experiment to characterize the reaction norms of the two races exposed to a gradient in water availability. We measured the response of five variables to the watering treatments: early survivorship, days to flowering, root/shoot dry …

Structure-Property Relationships Of Silicone Biofouling-Release Coatings: Effect Of Silicone Network Architecture On Pseudobarnacle Attachment Strengths, Judith Stein, Kathryn Truby, Christina Darkangelo Wood, Michael Takemori, Michael Vallance, Geoffrey Swain, Christopher Kavanagh, Brett Kovach, Michael Schultz, Deborah Wiebe, Eric Holm, Jean Montemarano, Dean Wendt, Celia Smith, Anne Meyer

Biological Sciences

Model silicone foul-release coatings with controlled molecular architecture were evaluated to determine the effect of compositional variables such as filler loading and crosslink density on pseudobarnacle attachment strength. Pseudobarnacle adhesion values correlated with filler loadings in both condensation and hydrosilylation-cured silicones. Variation of crosslink density of hydrosilylation-cured silicones had an insignificant effect on attachment strength. X-ray photoelectron spectroscopy (XPS) indicated that the mode of failure upon detachment of the pseudobarnacle was dependent upon the crosslink density; samples with high crosslink density failed cohesively within the silicone.

Removal Of Pcr Inhibitors From Soil Dna By Chemical Flocculation, Michael D. Braid, Laura M. Daniels, Christopher L. Kitts

Biological Sciences

Extracting high-purity DNA directly from soil has become essential for the study of microorganisms in environmental samples. However, many soils contain compounds that inhibit enzymes involved in manipulating DNA. In this study, chemical flocculation using multivalent cations was investigated as a potential method for eliminating soil-based inhibitors during the extraction process. The addition of AlNH4(SO4)2 during extraction significantly reduced the co-purification of PCR inhibitors with minimal loss of DNA yield.

Small Heat Shock Protein Responses Of A Closely Related Pair Of Desert And Coastal Encelia, Charles A. Knight, David D. Ackerly

Biological Sciences

Evolutionary variation for accumulation of small heat shock protein (sHsp) may contribute to thermal niche differentiation between species. Here we examine temperature and time-course-dependent variation for sHsp accumulation in a recently diverged pair of Encelia raised in a common environment: Encelia farinosa, common in the Mojave desert, and Encelia californica, which is found along the cool coastal bluffs of southern North America. Both species exhibit peak sHsp accumulation at 42^oC. Encelia californica accumulated greater levels of sHsp at temperatures below 42^oC, while E. farinosa had greater levels above 42^oC. Encelia farinosa accumulates …

Evolution And Plasticity Of Photosynthetic Thermal Tolerance, Specific Leaf Area And Leaf Size: Congeneric Species From Desert And Coastal Environments, Charles A. Knight, David D. Ackerly

Biological Sciences

• We examined whether increased high temperature photosynthetic thermal tolerance (PT), reduced specific leaf area (SLA) and reduced leaf size represent correlated and convergent adaptations for recently diverged Encelia, Salvia, Atriplex and Eriogonumcongeneric species pairs from contrasting thermal and water environments (the Mojave Desert and coastal California). We also studied whether variation in PT is associated with inducible small heat shock protein expression (sHsp).

• Traits were measured in a common environment (CE) and in the field to partition effects of phenotypic plasticity and genetic divergence.

• We found little evidence for convergent adaptation of PT (CE measurements). Field …

When Does A Reproducing Female Viper (Vipera Aspis) ‘Decide’ On Her Litter Size?, Olivier Lourdais, Xavier Bonnet, Richard Shine, Emily N. Taylor

Biological Sciences

Some organisms rely on stored energy to fuel reproductive expenditure (capital breeders) whereas others use energy gained during the reproductive bout itself (income breeders). Most species occupy intermediate positions on this continuum, but few experimental data are available on the timescale over which food intake can affect fecundity. Mark–recapture studies of free-ranging female aspic vipers Vipera aspis have suggested that reproductive output relies not only on the energy in fat bodies accumulated in previous years, but also on food intake immediately before ovulation. A simple experiment was conducted to test this hypothesis, maintaining female snakes in captivity throughout the vitellogenic …