Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 61 - 75 of 75

Full-Text Articles in Life Sciences

Insights From Comparative Analyses Of Aging In Birds And Mammals, Robert E. Ricklefs Jan 2010

Insights From Comparative Analyses Of Aging In Birds And Mammals, Robert E. Ricklefs

Robert Ricklefs

Many laboratory models used in aging research are inappropriate for understanding senescence in mammals, including humans, because of fundamental differences in life history, maintenance in artificial environments, and selection for early aging and high reproductive rate. Comparative studies of senescence in birds and mammals reveal a broad range in rates of aging among a variety of taxa with similar physiology and patterns of development. These comparisons suggest that senescence is a shared property of all vertebrates with determinate growth, that the rate of senescence has been modified by evolution in response to the potential life span allowed by extrinsic mortality …


Root Contraction Helps Protect The "Living Rock" Cactus Ariocarpus Fissuratus From Lethal High Temperatures When Growing In Rocky Soil, Gretchen North, T.Y. Garrett, C.V. Huynh Dec 2009

Root Contraction Helps Protect The "Living Rock" Cactus Ariocarpus Fissuratus From Lethal High Temperatures When Growing In Rocky Soil, Gretchen North, T.Y. Garrett, C.V. Huynh

Gretchen North

• Premise of the study: We investigated how the “living rock” cactus Ariocarpus fissuratus, like other low-growing desert plants, can endure potentially lethal high temperatures at the soil surface. Specifically, we examined how shoot descent by root contraction in the presence or absence of soil rocks influences shoot temperatures and transpiration. • Methods: Root contraction was identified by measuring shoot descent and anatomical analysis. Temperatures and transpiration were measured for plants at two heights in sandy and rocky soil, and temperature tolerances were determined by vital staining. • Key results: Plants embedded in rocky soil survived an extreme heat episode, …


Functional Anatomy Of Penaeid Shrimp, Gary Martin, Jo Hose Dec 2009

Functional Anatomy Of Penaeid Shrimp, Gary Martin, Jo Hose

Gary Martin

A comprehensive source of information on all aspects of shrimp production, this reference covers not only the global status of shrimp farming, but also examines shrimp anatomy and physiology. From nutrition to health management and harvesting issues to biosecurity, this well-researched volume evaluates existing knowledge, proposes new concepts, and questions common practices. With an extensive review on worldwide production systems, this compilation will be highly relevant to research scientists, students, and shrimp producers.


Biological Stoichiometry Of Plant Production: Metabolism, Scaling, And Ecological Response To Global Change, Andrew Kerkhoff, J.J. Elser, W.F. Fagan, B.J. Enquist Dec 2009

Biological Stoichiometry Of Plant Production: Metabolism, Scaling, And Ecological Response To Global Change, Andrew Kerkhoff, J.J. Elser, W.F. Fagan, B.J. Enquist

Andrew J Kerkhoff

No abstract provided.


A New Andean Species Of The Hypsiboas Pulchellus Group: Adults, Calls, And Phylogenetic Relationships, Edgar Lehr, Julian Faivovich, Karl-Heinz Jungfer Dec 2009

A New Andean Species Of The Hypsiboas Pulchellus Group: Adults, Calls, And Phylogenetic Relationships, Edgar Lehr, Julian Faivovich, Karl-Heinz Jungfer

Edgar Lehr

We describe a new species of the Hypsiboas pulchellus Group from the eastern Andes of central Peru (Region Pasco). Calls of both H. melanopleura and the new species are described. The new species is more similar to H. melanopleura and H. palaestes but differs in morphological characters and in coloration pattern. The new species and H. melanopleura are included in a molecular phylogenetic analysis of the H. pulchellus Group that shows them to be sister species and forming a second, independent, Andean clade within the group. New collecting sites for H. melanopleura are provided with the first record in the …


Genetic Variation For Susceptibility To Storm-Induced Stem Breakage In Solidago Altissima: The Role Of Stem Height And Morphology, M. Wise, W. Abrahamson Dec 2009

Genetic Variation For Susceptibility To Storm-Induced Stem Breakage In Solidago Altissima: The Role Of Stem Height And Morphology, M. Wise, W. Abrahamson

Warren G. Abrahamson, II

While storms can have obvious ecological impacts on plants, plants’ potential to respond evolutionarily to selection for increased resistance to storm damage has received little study. We took advantage of a thunderstorm with strong wind and hail to examine genetic variation for resistance to stem breakage in the herbaceous perennial Solidago altissima. The storm broke the apex of nearly 10% of 1883 marked ramets in a common-garden plot containing 26 genets of S. altissima. Plant genets varied 20-fold in resistance to breakage. Stem height was strongly correlated with resistance to breakage, with taller stems being significantly more susceptible. A stem’s …


Video: Body Languages: Choreographing Biology, Katja Kolcio Dec 2009

Video: Body Languages: Choreographing Biology, Katja Kolcio

Katja Kolcio Ph.D.

Co-taught by professors Manju Hingorani and Katja Kolcio at Wesleyan University, this course was an introduction to human biology. From scientific and choreographic perspectives, students practiced movement awareness and learned basic principles of choreography, and applied these skills to the exploration of human biology. Manju Hingorani, Professor of Molecular Biology and Biochemistry Katja Kolcio, Associate Professor of Dance and Environmental Studies


Spatiotemporal Variation Of Fruit Digestible-Nutrient Production In Florida's Uplands, J. Layne, W. Abrahamson Dec 2009

Spatiotemporal Variation Of Fruit Digestible-Nutrient Production In Florida's Uplands, J. Layne, W. Abrahamson

Warren G. Abrahamson, II

We examined annual total digestible nutrient (TDN) production by fruits of eight species (Quercus chapmanii, Q. geminata, Q. inopina, Q. laevis, Q. myrtifolia, Carya floridana, Sabal etonia, Serenoa repens) that account for the major proportion of TDN production by fruits and seeds in Florida’s xeric upland associations (southern ridge sandhill, sand pine scrub, scrubby flatwoods). Mean annual fruit TDN of all species combined over a 27-year span in sandhill and scrub and 24 years in scrubby flatwoods was highest (45.4 kg/ha) in sandhill, intermediate in scrubby flatwoods (28.8 kg/ha), and lowest in scrub (14.2 kg/ha). Sandhill fruit TDN production was …


Dc Expressing Transgene Foxp3 Are Regulatory Apc, Michael Lipscomb Dec 2009

Dc Expressing Transgene Foxp3 Are Regulatory Apc, Michael Lipscomb

Michael Lipscomb

Tolerogenic DC and suppressive Foxp3(+) Treg play important roles in preventing autoimmunity and allograft rejection. We report that (adenovirus mediated) ectopic expression of Foxp3 in human DC (i.e. DC.Foxp3) yields an APC that severely limits T-cell proliferation and type-1 immune responses from the naïve, but not memory, pool of responder T cells in vitro. In marked contrast, the frequencies of type-2 and Treg responses were dramatically increased after stimulation of naïve T cells with DC.Foxp3 versus control DC. DC.Foxp3-induced CD4(+)CD25(+) Treg cells potently suppressed the proliferation of, and IFN-gamma production from, CD4(+) and CD8(+) responder T cells. Notably, the immunosuppressive …


Nomenclatural Changes For Some Grasses In California And The Muhlenbergia Clade (Poaceae), James Payne Smith Jr. Dec 2009

Nomenclatural Changes For Some Grasses In California And The Muhlenbergia Clade (Poaceae), James Payne Smith Jr.

James Payne Smith

No abstract provided.


3hsds1和17hsds7基因5'上游区转录活性研究.Pdf, Xinxing Dong, Yi Xin, Ying Bai, Yunzhou Yang, Jibin Zhang, Meiying Fang, Gang Chen Dec 2009

3hsds1和17hsds7基因5'上游区转录活性研究.Pdf, Xinxing Dong, Yi Xin, Ying Bai, Yunzhou Yang, Jibin Zhang, Meiying Fang, Gang Chen

Jibin Zhang

3β-hydroxysteroid dehydrogenases (HSDs) and 17βHSDs are pivotal enzymes involved in synthesis, activation and deactivation of steroid hormones. Therefore, they play an important role to maintain homeostasis of hormone and regulate the synthesis and metabolism of hormones, and they are also related to metabolism of androstenone which can cause boar taint in male pigs. Through ligation of different PCR fragments of these genes from Large White pigs to pGL3-basic plasmid and subsequent transient transfection of constructed vectors into HepG2 cell culture, we found that the fragment from -1038bp to 45bp in porcine 3βHSD gene and the fragment from -966bp to 39bp …


Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole Dec 2009

Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole

Warren G. Abrahamson, II

Herbivores are among the most pervasive selective forces acting on plants, and the number of plant chemicals that presumably evolved for defense against herbivory is immense. In contrast, biologists are only beginning to appreciate the important roles that architectural traits can play in antiherbivore defense. One putative architectural-resistance trait is the nodding stem apex of some goldenrods (Solidago ; Asteraceae). Individuals of S. altissima genets that undergo temporary nodding in the late spring (i.e., “candy-cane ramets) have been shown to be more resistant than individuals of erect-stemmed genets to certain apex-attacking” herbivores. We tested the hypothesis that the greater resistance …


Nutrition As A Facilitator Of Host-Race Formation: The Role Of Food Quality In The Shift Of A Stem-Boring Beetle To A Gall Host, C. P. Blair, R. V. Schlanger, S. E. Diamond, W. G. Abrahamson Dec 2009

Nutrition As A Facilitator Of Host-Race Formation: The Role Of Food Quality In The Shift Of A Stem-Boring Beetle To A Gall Host, C. P. Blair, R. V. Schlanger, S. E. Diamond, W. G. Abrahamson

Warren G. Abrahamson, II

1. The importance of host-race formation to herbivorous insect diversity depends on the likelihood that successful populations can be established on a new plant host. A previously unexplored ecological aid to success on a novel host is better nutritional quality. The role of nutrition was examined in the shift of the stem-boring beetle Mordellistena convicta to fly-induced galls on goldenrod and the establishment there of a genetically distinct gall host race. 2. First, larvae of the host race inhabiting stems of Solidago gigantea were transplanted into stems and galls of greenhouse-grown S. gigantea plants. At the end of larval development, …


Children In Jeopardy: Anthropogenic Toxins And Childhood Exposure, Russell Butkus, Steve Kolmes Dec 2009

Children In Jeopardy: Anthropogenic Toxins And Childhood Exposure, Russell Butkus, Steve Kolmes

Steve Kolmes

No abstract provided.


Polyphyly Of The Pikeminnows (Teleostei: Cyprinidae) Inferred Using Mitochondrial Dna Sequences, T. Heath Ogden Dec 2009

Polyphyly Of The Pikeminnows (Teleostei: Cyprinidae) Inferred Using Mitochondrial Dna Sequences, T. Heath Ogden

T. Heath Ogden

The phylogenetic relationships of the Colorado pikeminnow Ptychocheilus lucius, northern pikeminnow P. oregonensis, Sacramento pikeminnow P. grandis, Umpqua pikeminnow P. umpquae, and hardhead Mylopharodon conocephalus were examined by using molecular data to investigate monophyly of the genus Ptychocheilus. Phylogenies generated using DNA sequence data from the cytochrome b and 16S ribosomal DNA genes of the mitochondrial genome reveal that Ptychocheilus is a polyphyletic genus and suggest that the taxonomy of the group is in need of further revision. These data yield insights into the evolution of the pikeminnows and help place the significant evolutionary events in context with the geological …