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Full-Text Articles in Biology

Bioengineering Tissue Constructs Using Elastic Alginate Hydrogels, Barbana A. Graham May 2010

Bioengineering Tissue Constructs Using Elastic Alginate Hydrogels, Barbana A. Graham

Biological Sciences

Bioengineered 3-D tissue constructs have great potential for understanding tissue development and tissue repair in patients lacking functional organs. One of the major challenges faced in the field, however, is to build functional tissue constructs that resemble tissue found in vivo. Cells and tissues in the body are organized into three-dimensional architectures, which interact with fibrillar extracellular matrix (ECM) proteins at a nanoscale. Both the topology and elasticity of the ECM play critical roles in regulating tissue formation. Alginate, a naturally occurring polysaccharide, is a good candidate to use as a biomaterial to mimic the topography and elasticity of the …


The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle In The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig M. Lind, Jerry F. Husak, Cas Eikenaar, Ignacio T. Moore, Emily N. Taylor May 2010

The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle In The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig M. Lind, Jerry F. Husak, Cas Eikenaar, Ignacio T. Moore, Emily N. Taylor

Biological Sciences

We describe the reproductive cycle of Northern Pacific rattlesnakes (Crotalus oreganus) by quantifying steroid hormone concentrations and observing reproductive behaviors in free-ranging individuals. Additionally, we examined reproductive tissues from museum specimens. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (March–October). We measured testosterone (T), 5α-dihydrotestosterone (DHT), and corticosterone (B) concentrations in both sexes and 17β-estradiol (E2) and progesterone (P) in females only. We observed reproductive behaviors (e.g., consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum collections to relate …


Correlated Evolution Of Defensive And Nutritional Traits In Native And Non-Native Plants, Nicole Molinari, Charles A. Knight May 2010

Correlated Evolution Of Defensive And Nutritional Traits In Native And Non-Native Plants, Nicole Molinari, Charles A. Knight

Biological Sciences

We performed a comparative analysis of defensive and nutritional plant traits responsible for differential herbivory in a series of experimental feeding trials with generalist herbivores. We measured three defensive traits (leaf strength, leaf mass per unit area and endophytic fungal infection) and two nutritional traits (foliar nitrogen and water) for 26 native and eight non-native plant species from coastal California shrublands. Our feeding trials involved three species of generalist herbivore (beet armyworm, cabbage looper and the garden snail) in two types of laboratory feeding trial (single plant species and preference tests). All traits were significantly related to the amount of …


Vascular Plants Of Adjacent Serpentine And Granite Outcrops On The Deer Isles, Maine, U.S.A, Nathaniel S. Pope, Tanner B. Harris, Nishanta Rajakaruna Apr 2010

Vascular Plants Of Adjacent Serpentine And Granite Outcrops On The Deer Isles, Maine, U.S.A, Nathaniel S. Pope, Tanner B. Harris, Nishanta Rajakaruna

Biological Sciences

We performed a comparative study of the vascular flora of a serpentine outcrop, Pine Hill, and that of a granite outcrop, Settlement Quarry, from Little Deer Isle and Deer Isle, respectively, Hancock County, Maine. We established four transects along a gradient from exposed to forested areas within each outcrop. Plants were recorded for presence and percent cover from circular plots along each transect. Soil and tissue samples were collected to examine soil-tissue elemental relations. One hundred thirty-two taxa were recorded from serpentine and 89 from granite. Fifty-seven taxa were shared by both sites. Species richness (α diversity) and diversity indices …


Bacteria - The Last Stronghold Of Lamarckism?, William D. Stansfield Mar 2010

Bacteria - The Last Stronghold Of Lamarckism?, William D. Stansfield

Biological Sciences

French naturalist J.B. Lamarck is most commonly known for popularizing the theory that some traits acquired during the life of an organism can be inherited in his 1809 book. German biologist A. Weismann presented evidence in his 1891 book that acquired traits were not heritable in sexually reproducing animals. But so little was known about bacteria that they were considered to be the last stronghold of Lamarckism. The “fluctuation test” of S. Luria and M. Delbrück in 1943 seemed to confirm that Lamarckism in bacteria was indeed dead. This review, however, proposes that today bacteria may be viewed as the …


Foraging Rates Of Larval Dragonfly Colonists Are Positively Related To Habitat Isolation: Results From A Landscape-Level Experiment, Shannon J. Mccauley, Tomas Brodin, John Hammond Mar 2010

Foraging Rates Of Larval Dragonfly Colonists Are Positively Related To Habitat Isolation: Results From A Landscape-Level Experiment, Shannon J. Mccauley, Tomas Brodin, John Hammond

Biological Sciences

There is increasing evidence of intraspecific variation in dispersal behavior. Individual differences in dispersal behavior may be correlated with other traits that determine the impact individuals have on patches they colonize. We established habitat patches—artificial pools—across a landscape, and these pools were naturally colonized by dragonfly larvae. Larvae were collected from pools at different levels of isolation and held under common lab conditions for 5 months. We then compared larval foraging rates. Foraging rate was positively related to habitat isolation, and colonists from the most isolated artificial pools had significantly higher foraging rates than individuals from the least isolated pools. …


Variation In The Heat Shock Response And Its Implication For Predicting The Effect Of Global Climate Change On Species' Biogeographical Distribution Ranges And Metabolic Costs, Lars Tomanek Feb 2010

Variation In The Heat Shock Response And Its Implication For Predicting The Effect Of Global Climate Change On Species' Biogeographical Distribution Ranges And Metabolic Costs, Lars Tomanek

Biological Sciences

The preferential synthesis of heat shock proteins (Hsps) in response to thermal stress [the heat shock response (HSR)] has been shown to vary in species that occupy different thermal environments. A survey of case studies of aquatic (mostly marine) organisms occupying stable thermal environments at all latitudes, from polar to tropical, shows that they do not in general respond to heat stress with an inducible HSR. Organisms that occupy highly variable thermal environments (variations up to >20°C), like the intertidal zone, induce the HSR frequently and within the range of body temperatures they normally experience, suggesting that the response is …


Hormones And Reproductive Cycles In Snakes, Emily N. Taylor, Dale F. Denardo Feb 2010

Hormones And Reproductive Cycles In Snakes, Emily N. Taylor, Dale F. Denardo

Biological Sciences

The study of the hormonal regulation of reproduction in snakes is in its infancy. Studies have disproportionately examined temperate zone viperid and colubrid snakes, especially the red-sided garter snake (Thamnophis sirtalis parietalis). Indeed, extensive observational and experimental studies on T. s. parietalis form the basis for our understanding of the hormonal regulation of reproduction in snakes. This review focuses on seasonal hormone concentrations in snakes in relation to events in the reproductive cycle; the limited data available on hypothalamic hormones, gonadotropins (GTHs), hormone receptors, and binding globulins; the neuroendocrinology of reproduction; and the environmental, social, physiological, and embryonic aspects of …


Layered Organization In The Coastal Ocean: An Introduction To Planktonic Thin Layers And The Loco Project, James M. Sullivan, D. Van Holliday, Malcolm Mcfarland, Margaret A. Mcmanus, Olivia M. Cheriton, Kelly J. Benoit-Bird, Louis Goodman, Zhankun Wang, John P. Ryan, Mark Stacey, Charles Greenlaw, Mark A. Moline Jan 2010

Layered Organization In The Coastal Ocean: An Introduction To Planktonic Thin Layers And The Loco Project, James M. Sullivan, D. Van Holliday, Malcolm Mcfarland, Margaret A. Mcmanus, Olivia M. Cheriton, Kelly J. Benoit-Bird, Louis Goodman, Zhankun Wang, John P. Ryan, Mark Stacey, Charles Greenlaw, Mark A. Moline

Biological Sciences

No abstract provided.


Integrated Measurements Of Acoustical And Optical Thin Layers Ii: Horizontal Length Scales, Mark A. Moline, Kelly J. Benoit-Bird, Ian C. Robbins, Maddie Schroth-Miller, Chad M. Waluk, Brian Zelenke Jan 2010

Integrated Measurements Of Acoustical And Optical Thin Layers Ii: Horizontal Length Scales, Mark A. Moline, Kelly J. Benoit-Bird, Ian C. Robbins, Maddie Schroth-Miller, Chad M. Waluk, Brian Zelenke

Biological Sciences

The degree of layered organization of planktonic organisms in coastal systems impacts trophic interactions, the vertical availability of nutrients, and many biological rate processes. While there is reasonable characterization of the vertical structure of these phenomena, the extent and horizontal length scale of variation has rarely been addressed. Here we extend the examination of the vertical scale in the first paper of the series to the horizontal scale with combined shipboard acoustic measurements and bio-optic measurements taken on an autonomous underwater vehicle. Measurements were made in Monterey Bay, CA from 2002 to 2008 for the bio-optical parameters and during 2006 …


Integrated Measurements Of Acoustical And Optical Thin Layers I: Vertical Scales Of Association, Kelly J. Benoit-Bird, Mark A. Moline, Chad M. Waluk, Ian C. Robbins Jan 2010

Integrated Measurements Of Acoustical And Optical Thin Layers I: Vertical Scales Of Association, Kelly J. Benoit-Bird, Mark A. Moline, Chad M. Waluk, Ian C. Robbins

Biological Sciences

This study combined measurements from multiple platforms with acoustic instruments on moorings and on a ship and optics on a profiler and an autonomous underwater vehicle (AUV) to examine the relationships between fluorescent, bioluminescent, and acoustically scattering layers in Monterey Bay during nighttime hours in July and August of 2006 and May of 2008. We identified thin bioluminescent layers that were strongly correlated with acoustic scattering at the same depth but were part of vertically broad acoustic features, suggesting layers of unique composition inside larger biomass features. These compositional thin layers nested inside larger biomass features may be a common …


Bioluminescence In The Sea, Steven H.D. Haddock, Mark A. Moline, James F. Case Jan 2010

Bioluminescence In The Sea, Steven H.D. Haddock, Mark A. Moline, James F. Case

Biological Sciences

Bioluminescence spans all oceanic dimensions and has evolved many times—from bacteria to fish—to powerfully influence behavioral and ecosystem dynamics. New methods and technology have brought great advances in understanding of the molecular basis of bioluminescence, its physiological control, and its significance in marine communities. Novel tools derived from understanding the chemistry of natural light-producing molecules have led to countless valuable applications, culminating recently in a related Nobel Prize. Marine organisms utilize bioluminescence for vital functions ranging from defense to reproduction. To understand these interactions and the distributions of luminous organisms, new instruments and platforms allow observations on individual to oceanographic …


On The Relationship Between Pollen Size And Genome Size, Charles A. Knight, Rachel B. Clancy, Lars Götzenberger, Leighton Dann, Jeremy M. Beaulieu Jan 2010

On The Relationship Between Pollen Size And Genome Size, Charles A. Knight, Rachel B. Clancy, Lars Götzenberger, Leighton Dann, Jeremy M. Beaulieu

Biological Sciences

Here we test whether genome size is a predictor of pollen size. If it were, inferences of ancient genome size would be possible using the abundant paleo-palynolgical record. We performed regression analyses across 464 species of pollen width and genome size. We found a significant positive trend. However, regression analysis using phylogentically independent contrasts did not support the correlated evolution of these traits. Instead, a large split between angiosperms and gymnosperms for both pollen width and genome size was revealed. Sister taxa were not more likely to show a positive contrast when compared to deeper nodes. However, significantly more congeneric …


Small Heat Shock Protein Responses Differ Between Chaparral Shrubs From Contrasting Microclimates, Charles A. Knight Jan 2010

Small Heat Shock Protein Responses Differ Between Chaparral Shrubs From Contrasting Microclimates, Charles A. Knight

Biological Sciences

Small heat shock protein (sHsp) responses were studied for two evergreen perennial shrubs in the northern California chaparral; one common on warm, south-facing slopes (Ceanothus cuneatus), and the other on cooler, north-facing slopes (Prunus ilicifolia). Small Hsp expression was induced experimentally for field collected leaves. Leaf collections were made where the species co-occur. Small Hsp expression was quantified using two antibodies, one specific to a chloroplast 22 kD sHsp and another that detects a broad range of sHsps. Differences between chloroplast sHsp accumulation, which protects thermally labile proteins in PSII, and the general sHsp response were …


Genome Size Is A Strong Predictor Of Root Meristem Growth Rate, Adam Gruner, Nathan Hoverter, Tylia Smith, Charles A. Knight Jan 2010

Genome Size Is A Strong Predictor Of Root Meristem Growth Rate, Adam Gruner, Nathan Hoverter, Tylia Smith, Charles A. Knight

Biological Sciences

Variation in genome size (GS) has been linked to several facets of the plant phenotype. Recently it was shown that GS is significantly correlated with cell size and the duration of the cell cycle. Here we test the hypothesis that GS might also be a predictor of apical root meristem growth rate (RMGR). We studied eight species of eudicots with varying GS using time-lapse microscopic image analysis. A significant negative exponential relationship was observed between GS and RMGR. Our results show significantly decreased RMGR for large genome species. This relationship represents a significant consequence of GS expansion in plants and …


The Proteomic Response Of The Mussel Congeners Mytilus Gallaprovincialis And M. Trossulus To Acute Heat Stress: Implications For Thermal Tolerance Limits And Metabolic Costs Of Thermal Stress, Lars Tomanek, Marcus J. Zuzow Jan 2010

The Proteomic Response Of The Mussel Congeners Mytilus Gallaprovincialis And M. Trossulus To Acute Heat Stress: Implications For Thermal Tolerance Limits And Metabolic Costs Of Thermal Stress, Lars Tomanek, Marcus J. Zuzow

Biological Sciences

The Mediterranean blue mussel, Mytilus galloprovincialis, an invasive species in California, has displaced the more heat-sensitive native congener, Mytilus trossulus, from its former southern range, possibly due to climate change. By comparing the response of their proteomes to acute heat stress we sought to identify responses common to both species as well as differences that account for greater heat tolerance in the invasive. Mussels were acclimated to 13°C for four weeks and exposed to acute heat stress (24°C, 28°C and 32°C) for 1 h and returned to 13°C to recover for 24 h. Using two-dimensional gel electrophoresis and …


Zooplankton Avoidance Of A Profiled Open-Path Fluorometer, Kelly J. Benoit-Bird, Mark A. Moline, Oscar M. Schofield, Ian C. Robbins, Chad M. Waluk Jan 2010

Zooplankton Avoidance Of A Profiled Open-Path Fluorometer, Kelly J. Benoit-Bird, Mark A. Moline, Oscar M. Schofield, Ian C. Robbins, Chad M. Waluk

Biological Sciences

Significant avoidance of acoustically detected zooplankton was observed in response to a profiling instrument package. Avoidance decreased acoustic scattering from zooplankton averaged over the entire profile by more than a factor of 2, while the maximum avoidance decreased zooplankton acoustic scattering by a factor of 15 over the depth of some discrete scattering layers. Experimental manipulation of the profiler and its instruments revealed that an open-path fluorometer was triggering the avoidance. Avoidance occurred at an average of 8 m below the profiler with a range between 2 and 13 m. Effect range was positively correlated with the average attenuation coefficient …


Effects Of Yogurt Starter Cultures On The Survival Of Lactobacillus Acidophilus, Elizabeth W. Ng, Marie Yeung, Phillip S. Tong Jan 2010

Effects Of Yogurt Starter Cultures On The Survival Of Lactobacillus Acidophilus, Elizabeth W. Ng, Marie Yeung, Phillip S. Tong

Biological Sciences

Recognized to confer health benefits to consumers, probiotics such as Lactobacillus acidophilus are commonly incorporated into fermented dairy products worldwide; among which yogurt is a popular delivery vehicle. To materialize most of the putative health benefits associated with probiotics, an adequate amount of viable cells must be delivered at the time of consumption. However, the loss in their viabilities during refrigerated storage has been demonstrated previously. This study focused on the effects of yogurt starter cultures on the survival of five strains of L. acidophilus, with emphases on low pH and acid production. Differential survival behavior between L. acidophilus strains …


The Metabolic Demands Of Swimming Behavior Influence The Evolution Of Skeletal Muscle Fiber Design In The Brachyuran Crab Family Portunidae, Kristin M. Hardy, Sean C. Lema, Stephen T. Kinsey Jan 2010

The Metabolic Demands Of Swimming Behavior Influence The Evolution Of Skeletal Muscle Fiber Design In The Brachyuran Crab Family Portunidae, Kristin M. Hardy, Sean C. Lema, Stephen T. Kinsey

Biological Sciences

We investigated the influence of intracellular diffusion on muscle fiber design in several swimming and non-swimming brachyuran crabs. Species with sustained swimming behavior had aerobic dark fibers subdivided into small metabolic functional units, creating short diffusion distances necessary to support the high rates of aerobic ATP turnover associated with endurance activity. This dark fiber design was observed in all swimming species including Ovalipes ocellatus, which has apparently evolved swimming behavior independently of other Portunidae. In addition, we observed fiber and subdivision size-dependent differences in organelle distribution. Mitochondria, which rely on oxygen to function, were uniformly distributed in small fibers/subdivisions, …


Using On‐Line Data Sources To Allow Students To Test Hypotheses About River Flow And Effects On Remotely Sensed Coastal Ocean Properties., Lawrence B. Cohoon, Kristin M. Hardy, Dustin M. Allen Jan 2010

Using On‐Line Data Sources To Allow Students To Test Hypotheses About River Flow And Effects On Remotely Sensed Coastal Ocean Properties., Lawrence B. Cohoon, Kristin M. Hardy, Dustin M. Allen

Biological Sciences

This exercise shows students how to relate remotely sensible properties of coastal waters to variations in river discharge using on‐line data resources. Students can then test hypotheses about the effects of climate changes (drought and wet periods), anthropogenic impacts (urbanized, agricultural, or undeveloped watersheds), or seasonality on river discharges and their consequences, if any, on coastal water quality as determined from remotely sensed properties. River flow has been measured for various periods of time, in some cases from almost the beginning of the 20th century, at many locations throughout the U.S. by the U.S. Geological Survey, with data on …


Meeting The Challenges: The Western Section's Role In Developing Tomorrow's Resource Management Professionals, John D. Perrine Jan 2010

Meeting The Challenges: The Western Section's Role In Developing Tomorrow's Resource Management Professionals, John D. Perrine

Biological Sciences

The following is a slightly edited version of a plenary address delivered at the Western Section annual meeting in January 2009. The plenary theme was “The view from the future: wildlife management challenges and opportunities of the next 100 years.” Key references are listed at the end of the address. Readers will also be interested in the Winter 2009 (Vol. 3, No. 4) issue of The Wildlife Professional, which contains a special section on the preparation and training of future wildlife professionals.