Life Sciences Commons^™

A Simple Spectrophotometric Streptavidin-Biotin Binding Assay Utilizing Biotin-4-Fluorescein., Mark Waner, David Mascotti

Mark J. Waner

A new assay for biotin binding capacity of Streptavidin (SA) is presented in this work. The assay is based on the large decrease in the extinction coefficient at 493 nm that accompanies binding of biotin-4-fluorescein (B4F) to SA. This decrease is attributed to formation of a charge transfer complex between the B4F-donor and one or more SA residues. We show that one may observe the stoichiometric binding via monitoring the absorbance at 493 nm using either SA or B4F as the titrant. The sensitivity of the assay is at the lower end of similar fluorimetric and photometric assays. Though the …

Co-Encapsulation Of Gallium With Gentamicin In Liposomes Enhances Antimicrobial Activity Of Gentamicin Against Pseudomonas Aeruginosa, Majed Halwani, B. Yebio, Zacharias E. Suntres, M. Alipour, Ali Azghani, A. Omri

Ali Azghani

The Internet Archive: How You Can Look Into The Web’S Past And Plan Your Future, Joe Zumalt

Joseph R. Zumalt

How to find historical pages on the World Wide Web with the Internet Archive.

Effects Of Oral Consumption Of The Green Tea Polyphenol Egcg In A Murine Model For Human Sjogren's Syndrome, An Autoimmune Disease., K. Gillespie, I. Kodani, D. Dickinson, K. Ogbureke, A. Camba, M. Wu, S. Looney, Tin-Chun Chu, H. Qin, F. Bisch, M. Sharawy, G. Schuster, S. Hsu

Tin-Chun Chu, Ph.D.

No abstract provided.

Demographic Parameters Of Yellowfin Croaker, Umbrina Roncador (Perciformes: Sciaenidae), From The Southern California Bight, Daniel Pondella, John Froeschke, Lynne Wetmore, Eric Miller, Charles Valle, Lea Medeiros

Daniel Pondella

The yellowfin croaker, Umbrina roncador Jordan & Gilbert, 1882, is a common nearshore and surf-zone species in the southern California bight. Age was determined for individuals (n = 1,209) using annual increments in otoliths, and size at age was modeled using the von Bertalanffy growth curve (L∞ = 307.754 mm, k = 0.278 yr−1, t0 = −0.995 yr; maximum age = 15 yr). Females (L∞= 313.173 mm, k = 0.307 yr−1, t0 = −0.771 yr) grew significantly faster and larger than males (L∞= 298.886, k = 0.269 yr−1, t0 = −1.072 yr). Age and growth modeling based upon otolith length …

Mexican Jay (Aphelocoma Ultramarina), John Mccormack, L. Brown

John E. McCormack

No abstract provided.

Stress-Induced Attenuation Of Acoustic Startle In Low-Saccharin-Consuming Rats., Clinton Chapman, Nancy Dess, Mitzi Gonzales, Cameryn Garrett

Clinton D Chapman

Exposure to stress can lead to either increased stress vulnerability or enhanced resiliency. Laboratory rats are a key tool in the exploration of basic biobehavioral processes underlying individual differences in the effect of stress on subsequent stressors' impact. The Occidental low (LoS) and high (HiS) saccharin-consuming rats, which differ in emotional reactivity, are useful in this effort. In the present study, footshock affected acoustic startle amplitude 4 h later among LoS but not HiS rats. Surprisingly, shock attenuated startle rather than sensitizing it, a finding not previously reported for male rats exposed to shock. Attenuation was blocked by administering the …

Gfp Tagging Of Sieve Element Occlusion (Seo) Proteins Results In Green Fluorescent Forisomes, Hélène Pélissier, Winfried Peters, Ray Collier, Aart Van Bel, Michael Knoblauch

Winfried S. Peters

Niche Expansion Leads To Small-Scale Adaptive Divergence Along An Elevation Gradient In A Medium-Sized Passerine Bird, John Mccormack, Thomas Smith

John E. McCormack

Niche expansion can lead to adaptive differentiation and speciation, but there are few examples from contemporary niche expansions about how this process is initiated. We assess the consequences of a niche expansion by Mexican jays (Aphelocoma ultramarina) along an elevation gradient. We predicted that jays at high elevation would have straighter bills adapted to feeding on pine cones, whereas jays at low elevation would have hooked bills adapted to feeding on acorns. We measured morphological and genetic variation of 95 adult jays and found significant differences in hook length between elevations in accordance with predictions, a pattern corroborated by analysis …

Integrating Paleoecology And Genetics Of Bird Populations In Two Sky Island Archipelagos, John Mccormack, Bonnie Bowen, Thomas Smith

John E. McCormack

Background: Genetic tests of paleoecological hypotheses have been rare, partly because recent genetic divergence is difficult to detect and time. According to fossil plant data, continuous woodland in the southwestern USA and northern Mexico became fragmented during the last 10,000 years, as warming caused cool-adapted species to retreat to high elevations. Most genetic studies of resulting 'sky islands' have either failed to detect recent divergence or have found discordant evidence for ancient divergence. We test this paleoecological hypothesis for the region with intraspecific mitochondrial DNA and microsatellite data from sky-island populations of a sedentary bird, the Mexican jay (Aphelocoma ultramarina). …

A Simple Spectrophotometric Streptavidin-Biotin Binding Assay Utilizing Biotin-4-Fluorescein., Mark Waner, David Mascotti

David P. Mascotti

A new assay for biotin binding capacity of Streptavidin (SA) is presented in this work. The assay is based on the large decrease in the extinction coefficient at 493 nm that accompanies binding of biotin-4-fluorescein (B4F) to SA. This decrease is attributed to formation of a charge transfer complex between the B4F-donor and one or more SA residues. We show that one may observe the stoichiometric binding via monitoring the absorbance at 493 nm using either SA or B4F as the titrant. The sensitivity of the assay is at the lower end of similar fluorimetric and photometric assays. Though the …

Psf2 Plays Important Roles In Normal Eye Development In Xenopus Laevis, Brian Walter, Kimberly Perry, Lisa Fukui, Erica Malloch, Jason Weaver, Jonathan Henry

Brian Walter

No abstract provided.

Iron Fertilization Of Kentucky Bluegrass, David Wehner, Jean Haley

David J. Wehner

Iron applications are sometimes used to enhance the color (darker green) of turfgrass stands even when iron is not deficient. A study was conducted to determine the feasibility of replacing a portion of the total yearly N applied to Kentucky bluegrass (Poa pratensis L.) with iron. Turfgrass response to iron chelate (Sequestrene 330) applications at 2.2 kg Fe ha^-1 in combination with three liquid-applied N sources (urea, Formolene, and FLUF) at 25 kg N ha^-1 was compared to turf response from applications of the N sources at 49 kg N ha^-1. Iron was substituted for …

Speciation In The Highlands Of Mexico: Genetic And Phenotypic Divergence In The Mexican Jay (Aphelocoma Ultramarina), John Mccormack, A. Peterson, E. Bonaccorso, Thomas Smith

John E. McCormack

The pine-oak woodlands of the Mexican highlands harbour significant biological diversity, yet little is known about the evolutionary history of organisms inhabiting this region. We assessed genetic and phenotypic differentiation in 482 individuals representing 27 populations of the Mexican jay (Aphelocoma ultramarina) — a widespread bird species of the Mexican highlands — to test whether populations in the central and northern Mexican sierras display discrete breaks between groups, which would be consistent with a role for the different mountain chains in divergence and speciation. We found abrupt breaks in mitochondrial DNA (mtDNA; ND2 and control region) delineating four major genetic …

Honey Bees: A History, Tammy Horn

Tammy Horn

Long known as the angels of agriculture, honey bees have received global attention due to losses attributed to a combination of factors: Colony Collapse Disorder, mites, deforestation and industrial agriculture. Honey bees provide pollination for crops, orchards and flowers; honey and wax for cosmetics, food and medicinal-religious objects; and inspiration to artists, architects and scientists.

Models For Predicting The Lower Limit Of The Canopy-Air Temperature Difference Of Two Cool Season Grasses, Dennis Martin, David Wehner, C. Throssell

David J. Wehner

Estimation of the lower limit of the canopy-air temperature differential, (T_c–T_a)_LL, is required for calculation of an empirically-based crop water stress, index. This research determined the complexity of model needed for accurate estimation of (T_c–T_a)_LL for several field grown cultivars of Kentucky bluegrass (Poa pratensis L.) and for creeping bentgrass (Agrostis stolonifera L. var. palustris (Huds.) Farw.). Regression models using vapor pressure deficit of the air (VPD), net radiation load (R_n), and wind speed (WS) were developed for predicting (T_c–T_{a …}

Melamine/Urea And Oxamide Fertilization Of Kentucky Bluegrass, David Wehner, Dennis Martin

David J. Wehner

The commercial lawn care industry represents a large market for N sources. A formulated melamine (2,4,6-triamino-s-triazine) plus urea combination (MLU) (45% melamine by weight) and oxamide were evaluated for use by the lawn care industry by comparing turfgrass response from these fertilizers to that from urea, sulfur coated urea (SCU), ureaformaldehyde (Nitroform), and a non-fertilized check. Fertilizers were applied four times per year to field plots of Kentucky bluegrass (Poa pratensis L.) growing on a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) at a rate of 49 kg N ha-1 per application. Color ratings and clipping weights were determined …

Why Are Incubation Periods Longer In The Tropics? A Common-Garden Experiment With House Wrens Reveals It Is All In The Egg, Given Harper, W. Douglas Robinson, John D. Styrsky, Brian J. Payne, Charles F. Thompson

Given Harper

Anisotropic Contraction In Forisomes: Simple Models Won't Fit, Winfried Peters, Michael Knoblauch, Stephen Warmann, William Pickard, Amy Shen

Winfried S. Peters

Responses To Multi-Directional Surface Translations Involve Redistribution Of Proximal Versus Distal Strategies To Maintain Upright Posture, Stephanie L. Jones, Sharon M. Henry, Christine C. Raasch, Juvena R. Hitt, Janice Y. Bunn

Stephanie Jones

Evaluation of postural control in multiple planes is necessary to determine the movement strategies used to respond to unexpected perturbations. The present study quantified net joint torques of the lower limbs and trunk in the sagittal and frontal planes following multi-directional surface translations. Twenty-one healthy subjects stood with feet on separate force plates mounted on a moveable platform, translated unexpectedly in one of 12 directions. Peak net torque magnitudes and latencies following perturbation onset were determined as were the relative contributions of each joint to total torque production. Magnitude of net torque generated by each leg varied by perturbation direction, …

Probiotics: 100 Years (1907-2007) After Elie Metchnikoff's Observations, Kingsley Anukam, Gregor Reid

Kingsley C Anukam

No abstract provided.

Dendritic Cells As Immune Regulators: The Mouse Model, Kristin Griffiths, Helen O'Neill

Helen O'Neill

Dendritic cells (DC) are central to the immune system because of their role in antigen presentation leading to either tolerance or immunity among cells of the adaptive immune response. It is becoming increasingly evident that DC show extensive plasticity in terms of their origin and function, giving rise to a number of subsets represented differentially in all lymphoid organs. This article considers the tolerogenic capacity of murine DC and draws a distinction between DC that induce tolerance in the immature state and immunity in an inflammatory context, and those that act as regulatory cells inducing immunosuppression in the presence of …

Definition Of Global And Transcript-Specific Mrna Export Pathways In Metazoans, Natalie Farny, Jessica Hurt, Pamela Silver

Natalie G. Farny

Eukaryotic gene expression requires export of messenger RNAs (mRNAs) from their site of transcription in the nucleus to the cytoplasm where they are translated. While mRNA export has been studied in yeast, the complexity of gene structure and cellular function in metazoan cells has likely led to increased diversification of these organisms' export pathways. Here we report the results of a genome-wide RNAi screen in which we identify 72 factors required for polyadenylated [poly-(A(+))] mRNA export from the nucleus in Drosophila cells. Using structural and functional conservation analysis of yeast and Drosophila mRNA export factors, we expose the evolutionary divergence …

'Partial Derivatives: Are You Kidding?': Teaching Thermodynamics Using Virtual Substance, Chrystal Bruce, Carribeth Bliem, John Papanikolas

Chrystal D. Bruce

No abstract provided.

Revisiting Classic Water Erosion Models In Drylands: The Strong Impact Of Biological Soil Crusts, Veer Chaudhary

V. Bala Chaudhary

Soil erosion and subsequent degradation has been a contributor to societal collapse in the past and is one of the major expressions of desertification in arid regions. The revised universal soil loss equation (RUSLE) models soil lost to water erosion as a function of climate erosivity (the degree to which rainfall can result in erosion), topography, soil erodibility, and land use/management. The soil erodibility factor (K) is primarily based upon inherent soil properties (those which change slowly or not at all) such as soil texture and organic matter content, while the cover/management factor (C) is based on several parameters including …

Invited Review: Heat Shock Proteins And Exercise: A Primer, Earl Noble, Kevin Milne, C.W. Melling

Jamie Melling

Heat shock proteins (HSPs) are, in general, prosurvival molecules within the cellular environment, and the overexpression of even just 1 family of HSPs can lead to protection against and improvements after a variety of stressors. Not surprisingly, a fertile area of study has grown out of effors to exploit the innate biologic behaviour of HSPs. Exercise, because of the inherent physiologic stresses associated with it, is but 1 stimulus that can result in a robust increase in various HSPs in several tissues, not the least of which happen to be the heart and skeletal muscle. The purpose of this review …

Combating Drug Resistance – Identifying Resilient Molecular Targets And Robust Drugs, Celia Schiffer

Celia A. Schiffer

In: Robert M. Stroud and Janet Finer-Moore, Computational and Structural Approaches to Drug Discovery: Ligand-Protein Interactions, Royal Society of Chemistry, 2008, Chapter 7, p. 127-132. ISBN 0854043659, 9780854043651.

Mechanism Of Cu+-Transporting Atpases: Soluble Cu+ Chaperones Directly Transfer Cu+ To Transmembrane Transport Sites, José Argüello, Manuel Gonzalez-Guerrero

José M. Argüello

As in other P-type ATPases, metal binding to transmembrane metal-binding sites (TM-MBS) in Cu(+)-ATPases is required for enzyme phosphorylation and subsequent transport. However, Cu(+) does not access Cu(+)-ATPases in a free (hydrated) form but is bound to a chaperone protein. Cu(+) transfer from Cu(+) chaperones to regulatory cytoplasmic metal-binding domains (MBDs) present in these ATPases has been described, but there is no evidence of a proposed subsequent Cu(+) movement from the MBDs to the TM-MBS. Alternatively, we postulate the parsimonious Cu(+) transfer by the chaperone directly to TM-MBS. Testing both models, the delivery of Cu(+) by Archaeoglobus fulgidus Cu(+) chaperone …

Nutrient Stress And Gall Flies Interact To Affect Floral-Sex Ratio In Gynomonoecious Solidago Altissima (Asteraceae), Warren Abrahamson, M.J. Wise, L.E. Coffey

Warren G. Abrahamson, II

No abstract provided.

Good Mothers, Bad Mothers, And Resistance To Herbivory In Solidago Altissima, Warren Abrahamson, M.J. Wise, J.M. Partelow, K.J. Everson, M.K. Anselmo

Warren G. Abrahamson, II

No abstract provided.