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2011

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Full-Text Articles in Social and Behavioral Sciences

Integrated Analysis Of Content And Construct Validity, Byron Gajewski, Larry Price, Valorie Coffland, Diane Boyle, Marjorie Bott Apr 2015

Integrated Analysis Of Content And Construct Validity, Byron Gajewski, Larry Price, Valorie Coffland, Diane Boyle, Marjorie Bott

Diane Kay Boyle PhD, RN, FAAN

Establishing adequacy of psychometric properties of an instrument involves acquisition and evaluation of evidence based on item content and internal structure. Content validity evidence consists of subject matter experts providing quantitative ratings of the extent to which items are a representative sample of targeted domain. Evidence of internal structure includes factor analytic studies and examination of item interrelationships based on item responses from participants. Although subject matter expert ratings and participant response data are traditionally analyzed separately, each serves to inform the other in important ways. We propose integrating subject matter experts’ and participants’ data seamlessly to establish a unified ...


Take Pride In America In Southern Nevada: Annual Progress Report, Period Covering January 1, 2011 - December 31, 2011, Margaret N. Rees Dec 2011

Take Pride In America In Southern Nevada: Annual Progress Report, Period Covering January 1, 2011 - December 31, 2011, Margaret N. Rees

Anti-littering Programs

  • A meeting of stakeholders across Nevada was held to explore the potential for statewide collaboration on litter and dumping issues.
  • Website activity for the first three quarters of the year averaged 1,122 hits per month, with an average of 1,927 pages viewed per month.
  • The team attended 12 community outreach events resulting in 2,154 direct contacts and 324 new mailing list records.
  • The Take Pride in America (TPIA) in Southern Nevada completed a total of 41 volunteer events contributing a total of 10,779 volunteer hours.
  • The TPIA team filed a no-cost extension to SNPLMA and received ...


Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Quarterly Progress Report, Period Covering October 1, 2011 To December 31, 2011, Margaret N. Rees Dec 2011

Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Quarterly Progress Report, Period Covering October 1, 2011 To December 31, 2011, Margaret N. Rees

Get Outdoors Nevada

  • The number of records in the volunteer database decreased by 20.7% over the last quarter. The database now contains 7,072 records.
  • Results show an average of 1,080 visits per month, and with an average of 2,328 pages viewed per month.
  • Get Outdoors Nevada supported 22 volunteer events in a variety of ways. These events utilized 867 volunteers whom contributed approximately 3,774.5 hours of service.
  • Two community outreach events were attended, resulting in 476 direct contacts with 50 names added to the database.
  • The 7th Annual Volunteer Recognition Banquet was held on 11/5/11 ...


Daily Stock Market Movement From Oscillating Social Mood Factors, Cari Bourette Dec 2011

Daily Stock Market Movement From Oscillating Social Mood Factors, Cari Bourette

Cari Bourette

Since 2006, there has been ongoing research into the correlation of a set of oscillating mood factors and socioeconomic, geopolitical, and natural events with the goal of forecasting increased risks of destabilizing events. While promising results have been forthcoming, it has been difficult to present models that allowed those outside a small circle of specialists to participate. Between July 2007 and June 2010, weekly social mood projections, as published in monthly issues of MoodCompass, were used to develop a model to convert four oscillating mood factors into stock market expectations. This model was modified to generate signals of projected stock ...


A Review Of Baobab (Adansonia Digitata) Products: Effect Of Processing Techniques, Medicinal Properties And Uses, Donatien Kabore, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Clarise Compaoré, Mamoudou H. Dicko Prof., Mogens Jacobsen Dec 2011

A Review Of Baobab (Adansonia Digitata) Products: Effect Of Processing Techniques, Medicinal Properties And Uses, Donatien Kabore, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Clarise Compaoré, Mamoudou H. Dicko Prof., Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

A general literature review including the effect of processing techniques, medicinal value and uses of baobab tree is reported in this manuscript. Baobab tree has multi-purpose uses, as it produces food and non-food products such as medicines, fuel, timber, fodder. Every part of the baobab tree is reported to be useful. The seeds, leaves, roots, flowers, fruit pulp and bark of baobab are edible. Baobab leaves are used in the preparation of soup. Seeds are used as a thickening agent in soups, but they can be fermented and used as a flavouring agent or roasted and eaten as snacks. The ...


Bargaining And Pricing In Networked Economic Systems, Tanmoy Chakraborty Dec 2011

Bargaining And Pricing In Networked Economic Systems, Tanmoy Chakraborty

Publicly Accessible Penn Dissertations

Economic systems can often be modeled as games involving several agents or players who act according to their own individual interests. Our goal is to understand how various features of an economic system affect its outcomes, and what may be the best strategy for an individual agent.

In this work, we model an economic system as a combination of many bilateral economic opportunities, such as that between a buyer and a seller. The transactions are complicated by the existence of many economic opportunities, and the influence they have on each other. For example, there may be several prospective sellers and ...


The Massachusetts Environmental Industry: Facing The Challenges Of Maturity, Betty J. Diener, David Terkla, Erick Cooke Dec 2011

The Massachusetts Environmental Industry: Facing The Challenges Of Maturity, Betty J. Diener, David Terkla, Erick Cooke

David G. Terkla

For most of the past 20 years, the environmental industry has been a very significant one, both in Massachusetts and across the country. Some have placed it alongside the electronics, computer hardware, software, biotechnology, fiber optics, and composite materials industries as part of the high-technology sector that has diversified and strengthened the state’s economy. Nationally, environmental industry employment exceeded that of several major manufacturing industries, including chemicals, paper, and aerospace. In the late 1990s, however, the momentum of the environmental movement began to wane. A decline in both employment and sales suggests that many of the most pressing environmental ...


Satellite Evidence For A Large Source Of Formic Acid From Boreal And Tropical Forests, T Stavrakou, J F. Muller, J Peeters, A Razavi, L Clarisse, C Clerbaux, P Coheur, D Hurtmans, M De Maziere, C Vigouroux, Nicholas Deutscher, David Griffith, Nicholas Jones, Clare Paton-Walsh Dec 2011

Satellite Evidence For A Large Source Of Formic Acid From Boreal And Tropical Forests, T Stavrakou, J F. Muller, J Peeters, A Razavi, L Clarisse, C Clerbaux, P Coheur, D Hurtmans, M De Maziere, C Vigouroux, Nicholas Deutscher, David Griffith, Nicholas Jones, Clare Paton-Walsh

Faculty of Science - Papers (Archive)

Formic acid contributes significantly to acid rain in remote environments1, 2. Direct sources of formic acid include human activities, biomass burning and plant leaves. Aside from these direct sources, sunlight-induced oxidation of non-methane hydrocarbons (largely of biogenic origin) is probably the largest source3, 4. However, model simulations substantially underpredict atmospheric formic acid levels5, 6, 7, indicating that not all sources have been included in the models. Here, we use satellite measurements of formic acid concentrations to constrain model simulations of the global formic acid budget. According to our simulations, 100–120 Tg of formic acid is produced annually, which is ...


Lesson Not Learned: Deepwater Horizon Research And Media Coverage Exposes Gaps In Knowledge And Risky Protocol Within The Oil Industry, Lauren Haller Dec 2011

Lesson Not Learned: Deepwater Horizon Research And Media Coverage Exposes Gaps In Knowledge And Risky Protocol Within The Oil Industry, Lauren Haller

Honors Theses

An insatiable thirst for oil has led poorly coordinated, risk-prone megasystems deeper into the ocean in search of new oil reserves. Profit-driven agendas at the corporate level have a top-down effect within these megasystems. Cost-cutting and risk-downplaying leaves the field employees unprepared to handle emergencies. A series of costly mistakes led to the 2010 BP Deepwater Horizon oil spill, which caused extensive damage to an already fragile ecosystem in the Gulf of Mexico. The wealth and political influence of the oil industry overpowers lax regulatory agencies and legislation-even though media and research has exposed frustrating parallels between the Deepwater Horizon ...


The Chernobyl Disaster : Reflection After 25 Years = 切爾諾貝爾核災難25年後的反思, Valentin Yakushik Dec 2011

The Chernobyl Disaster : Reflection After 25 Years = 切爾諾貝爾核災難25年後的反思, Valentin Yakushik

South South Forum 南南論壇

The adverse technogenic impact of industrial accidents that have gripped the world in recent decades definitely testifies to the problem-ridden character of contemporary economic and technological development. This is especially evident on the example of nuclear industry, which proved to be a source of dangerous pollution in case of potential (and real) catastrophes, as recently borne out by the Fukushima disaster. In this regard, the issues of Chernobyl disaster once again become the part of the discourse centered on the analysis of global nuclear industry problems. Likewise, current situation in Ukraine demands deeper investigation of the problems of technological development ...


2010 Massachusetts Recreational Boater Survey: Final Report Submitted To The Massachusetts Ocean Partnership, Dan Hellin, Jack Wiggin, Kristin Uiterwyk, Kim Starbuck, Nicholas Napoli, David Terkla, Chris Watson, Anthony Roman, Leona Roach, Tim Welch Dec 2011

2010 Massachusetts Recreational Boater Survey: Final Report Submitted To The Massachusetts Ocean Partnership, Dan Hellin, Jack Wiggin, Kristin Uiterwyk, Kim Starbuck, Nicholas Napoli, David Terkla, Chris Watson, Anthony Roman, Leona Roach, Tim Welch

David G. Terkla

The Massachusetts Ocean Management Plan (Plan) completed in 2009 recognized recreational boating as an activity with “significant actual and prospective conflicts among multiple waterway uses in Massachusetts” and included the economic value of recreational boating as a key socio-economic indicator that will be used to inform coastal management. At the time of Plan completion, statistically robust recreational boating data were identified as an important need for comprehensive ocean planning. To fill this data gap, the 2010 Massachusetts Recreational Boater Survey gathered information on boating activity in Massachusetts’ coastal and ocean waters directly from recreational boaters. Researchers sent 10,000 surveys ...


Model For Amorphous Aggregation Processes, Samual Stranks, Heath Ecroyd, Steve Van Sluyter, Elizabeth J. Waters, John A. Carver, Lorenz Von Smekal Dec 2011

Model For Amorphous Aggregation Processes, Samual Stranks, Heath Ecroyd, Steve Van Sluyter, Elizabeth J. Waters, John A. Carver, Lorenz Von Smekal

Heath Ecroyd

The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first ...


Endogenous Redox Activity In Mouse Spermatozoa And Its Role In Regulating The Tyrosine Phosphorylation Events Associated With Sperm Capacitation, Heath W. Ecroyd, Russell C. Jones, Robert J. Aitken Dec 2011

Endogenous Redox Activity In Mouse Spermatozoa And Its Role In Regulating The Tyrosine Phosphorylation Events Associated With Sperm Capacitation, Heath W. Ecroyd, Russell C. Jones, Robert J. Aitken

Heath Ecroyd

We investigated the role of endogenous redox activity in regulating the signal transduction pathway leading to tyrosine phosphorylation in mouse spermatozoa. Endogenous redox activity was monitored using a luminol-peroxidase chemiluminescent probe. Chemiluminescence increased in spermatozoa that were actively undergoing cAMP-mediated tyrosine phosphorylation events associated with capacitation and was inhibited in a dose-dependent manner by addition of catalase or diphenylene iodonium, both of which also inhibited tyrosine phosphorylation within the cell at points downstream of cAMP. Excluding bicarbonate from the incubation medium reduced the redox activity of sperm by 80-90% and dramatically reduced tyrosine phosphorylation. This study provides the first evidence ...


Role Of The Epididymis In Sperm Competition, Russell Jones, Jl Dacheux, Brett Nixon, Heath Ecroyd Dec 2011

Role Of The Epididymis In Sperm Competition, Russell Jones, Jl Dacheux, Brett Nixon, Heath Ecroyd

Heath Ecroyd

Although it is generally understood that the testes recruited kidney ducts for reproductive function during the evolution of vertebrates, little is understood of the biological significance of the adaptation. In the context of the evolution of the mammalian epididymis, this report provides evidence that a major role of the epididymis is to enhance a male's chance of achieving paternity in a competitive mating system. A unique example of sperm cooperation, in monotremes is used as evidence that the epididymis produces sperm competition proteins to form groups of 100 sperm into bundles that have a forward motility nearly thrice that ...


Carboxymethylated-K-Casein: A Convenient Tool For The Identification Of Polyphenolic Inhibitors Of Amyloid Fibril Formation, John A. Carver, Peter J. Duggan, Heath Ecroyd, Yanqin Liu, Adam G. Meyer, C E. Tranberg Dec 2011

Carboxymethylated-K-Casein: A Convenient Tool For The Identification Of Polyphenolic Inhibitors Of Amyloid Fibril Formation, John A. Carver, Peter J. Duggan, Heath Ecroyd, Yanqin Liu, Adam G. Meyer, C E. Tranberg

Heath Ecroyd

Reduced and carboxymethylated-κ-casein (RCM-κ-CN) is a milk-derived amyloidogenic protein that readily undergoes nucleation-dependent aggregation and amyloid fibril formation via a similar pathway to disease-specific amyloidogenic peptides like amyloid beta (Aβ), which is associated with Alzheimer’s disease. In this study, a series of flavonoids, many known to be inhibitors of Aβ fibril formation, were screened for their ability to inhibit RCM-κ-CN fibrilisation, and the results were compared with literature data on Aβ inhibition. Flavonoids that had a high degree of hydroxylation and molecular planarity gave good inhibition of RCM-κ-CN fibril formation. IC50 values were between 10- and 200-fold higher with ...


Tyrosine Phosphorylation Of Hsp-90 During Mammalian Sperm Capacitation, Heath Ecroyd, Russell Jones, Robert Aitken Dec 2011

Tyrosine Phosphorylation Of Hsp-90 During Mammalian Sperm Capacitation, Heath Ecroyd, Russell Jones, Robert Aitken

Heath Ecroyd

The process of sperm capacitation is correlated with activation of a signal transduction pathway leading to protein tyrosine phosphorylation. Whereas phosphotyrosine expression is an essential prerequisite for fertilization, the proteins that are phosphorylated during capacitation have not yet been identified. In the present study, we observed that a major target of this signaling pathway is the molecular chaperone protein, heat shock protein (HSP)-86, a member of the HSP-90 family of HSPs. We used cross-immunoprecipitation experiments to confirm the tyrosine phosphorylation of HSP-86, a process that is not inhibited by the ansamycin antibiotic, geldanamycin. The general significance of these findings ...


Dissociation From The Oligomeric State Is The Rate-Limiting Step In Fibril Formation By Kappa-Casein, Heath Ecroyd, Tomas Koudelka, David Thorn, Danielle Williams, Glyn Devlin, Peter Hoffmann, John Carver Dec 2011

Dissociation From The Oligomeric State Is The Rate-Limiting Step In Fibril Formation By Kappa-Casein, Heath Ecroyd, Tomas Koudelka, David Thorn, Danielle Williams, Glyn Devlin, Peter Hoffmann, John Carver

Heath Ecroyd

Amyloid fibrils are aggregated and precipitated forms of protein in which the protein exists in highly ordered, long, unbranching threadlike formations that are stable and resistant to degradation by proteases. Fibril formation is an ordered process that typically involves the unfolding of a protein to partially folded states that subsequently interact and aggregate through a nucleation-dependent mechanism. Here we report on studies investigating the molecular basis of the inherent propensity of the milk protein, kappa-casein, to form amyloid fibrils. Using reduced and carboxymethylated kappa-casein ( RCM kappa-CN), we show that fibril formation is accompanied by a characteristic increase in thioflavin T ...


An Epididymal Form Of Cauxin, A Carboxylesterase-Like Enzyme, Is Present And Active In Mammalian Male Reproductive Fluids, Heath W. Ecroyd, Maya Belghazi, Jl Dacheux, M Miyazaki, T Yamashita, Jl Gatti Dec 2011

An Epididymal Form Of Cauxin, A Carboxylesterase-Like Enzyme, Is Present And Active In Mammalian Male Reproductive Fluids, Heath W. Ecroyd, Maya Belghazi, Jl Dacheux, M Miyazaki, T Yamashita, Jl Gatti

Heath Ecroyd

Mass spectrometric analysis of a prion protein (PrP)-containing complex isolated from ram cauda epididymal fluid revealed a protein that showed homology to a carboxylesterase-like protein previously identified in cat urine (cauxin). Using anticauxin antibodies, immunoreactive bands were detected in corpus and cauda epididymal fluid from all mammals tested (ram, boar, mouse, and cat). In the ram, the protein was also present in seminal fluid but not found to be associated with sperm. The bands reacting with the anti-cauxin antibody coincided with those having esterase activity in a zymographic assay and its levels paralleled the esterase activity of native epididymal ...


The Dissociated Form Of Kappa-Casein Is The Precursor To Its Amyloid Fibril Formation, Heath Ecroyd, David Thorn, Yanqin Liu, John Carver Dec 2011

The Dissociated Form Of Kappa-Casein Is The Precursor To Its Amyloid Fibril Formation, Heath Ecroyd, David Thorn, Yanqin Liu, John Carver

Heath Ecroyd

Bovine milk kappa-casein forms a self-associating oligomeric micelle-like species, in equilibrium with dissociated forms. In its native form, intra- and inter-molecular disulfide bonds lead to the formation of multimeric species ranging from monomers to decamers. When incubated under conditions of physiological pH and temperature, both reduced and non-reduced kappa-casein form highly structured beta-sheet amyloid fibrils. We investigated whether the precursor to kappa-casein fibril formation is a dissociated state of the protein or its oligomeric micelle-like form. We show that reduced kappa-casein is capable of forming fibrils well below its critical micelle concentration, i.e. at concentrations where only dissociated forms ...


The Effect Of Small Molecules In Modulating The Chaperone Activity Of Alpha B-Crystallin Against Ordered And Disordered Protein Aggregation, Heath Ecroyd, John Carver Dec 2011

The Effect Of Small Molecules In Modulating The Chaperone Activity Of Alpha B-Crystallin Against Ordered And Disordered Protein Aggregation, Heath Ecroyd, John Carver

Heath Ecroyd

Protein aggregation can proceed via disordered or ordered mechanisms, with the latter being associated with amyloid fibril formation, which has been linked to a number of debilitating conditions including Alzheimer's, Parkinson's and Creutzfeldt-Jakob diseases. Small heat-shock proteins (sHsps), such as alpha B-crystallin, act as chaperones to prevent protein aggregation and are thought to play a key role in the prevention of protein-misfolding diseases. In this study, we have explored the potential for small molecules such as arginine and guanidine to affect the chaperone activity of alpha B-crystallin against disordered (amorphous) and ordered (amyloid fibril) forms of protein aggregation ...


The Interaction Of Unfolding Α-Lactalbumin And Malate Dehydrogenase With The Molecular Chaperone Αb-Crystallin: A Light And X-Ray Scattering Investigation, J W. Regini, Heath Ecroyd, Sarah Meehan, Kristen Bremmell, Matthew J. Clarke, Donna Lammie, Tim Wess, John A. Carver Dec 2011

The Interaction Of Unfolding Α-Lactalbumin And Malate Dehydrogenase With The Molecular Chaperone Αb-Crystallin: A Light And X-Ray Scattering Investigation, J W. Regini, Heath Ecroyd, Sarah Meehan, Kristen Bremmell, Matthew J. Clarke, Donna Lammie, Tim Wess, John A. Carver

Heath Ecroyd

Purpose: The molecular chaperone αB-crystallin is found in high concentrations in the lens and is present in all major body tissues. Its structure and the mechanism by which it protects its target protein from aggregating and precipitating are not known. Methods: Dynamic light scattering and X-ray solution scattering techniques were used to investigate structural features of the αB-crystallin oligomer when complexed with target proteins under mild stress conditions, i.e., reduction of α- lactalbumin at 37 °C and malate dehydrogenase when heated at 42 °C. In this investigation, the size, shape and particle distribution of the complexes were determined in ...


Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath Ecroyd, Shaun Roman, Robert Aitken Dec 2011

Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath Ecroyd, Shaun Roman, Robert Aitken

Heath Ecroyd

The capacitation of mammalian spermatozoa involves the activation of a cAMP-mediated signal transduction pathway that drives tyrosine phosphorylation via mechanisms that are unique to this cell type. Controversy surrounds the impact of extracellular calcium on this process, with positive and negative effects being recorded in independent publications. We clearly demonstrate that the presence of calcium in the external medium decreases tyrosine phosphorylation in both human and mouse spermatozoa. Under these conditions, a rise in intracellular pH was recorded, however, this event was not responsible for the observed changes in phosphotyrosine expression. Rather, the impact of calcium on tyrosine phosphorylation in ...


(-)-Epigallocatechin-3-Gallate (Egcg) Maintains K-Casein In Its Pre-Fibrillar State Without Redirecting Its Aggregation Pathway, Sean A. Hudson, Heath Ecroyd, Francis C. Dehle, Ian F. Musgrave, John Carver Dec 2011

(-)-Epigallocatechin-3-Gallate (Egcg) Maintains K-Casein In Its Pre-Fibrillar State Without Redirecting Its Aggregation Pathway, Sean A. Hudson, Heath Ecroyd, Francis C. Dehle, Ian F. Musgrave, John Carver

Heath Ecroyd

The polyphenol (-)-epigallocatechin-3-gallate (EGCG) has recently attracted much research interest in the field of protein-misfolding diseases because of its potent anti-amyloid activity against amyloid-beta, alpha-synuclein and huntingtin, the amyloid-fibril-forming proteins involved in Alzheimer's, Parkinson's and Huntington's diseases, respectively. EGCG redirects the aggregation of these polypeptides to a disordered off-folding pathway that results in the formation of non-toxic amorphous aggregates. whether this anti-fibril activity is specific to these disease-related target proteins or ismore generic remains to be established. In addition, the mechanism by which EGCG exerts its effects, as with all anti-amyloidogenic polyphenols, remains unclear. To address these ...


The Two Faced Nature Of Milk Casein Proteins: Amyloid Fibril Formation And Chaperone-Like Activity, David Thorn, Heath Ecroyd, John Carver Dec 2011

The Two Faced Nature Of Milk Casein Proteins: Amyloid Fibril Formation And Chaperone-Like Activity, David Thorn, Heath Ecroyd, John Carver

Heath Ecroyd

Molecular chaperones are a diverse group of proteins that stabilise partially folded target proteins to prevent their misfolding, aggregation and potential precipitation under conditions of cellular stress, e.g. elevated temperature. Protein aggregation, particularly the formation of highly ordered protein aggregates termed amyloid fibrils, is of considerable research interest because of its intimate association with a wide range of debilitating diseases, including Alzheimer's, Parkinson's and Huntington's diseases and type II diabetes. In this review, we discuss the ability of the milk casein proteins to act in a chaperone-like manner. This property is of biological importance since at ...


New Proteins Identified In Epididymal Fluid From The Platypus (Ornithorhynchus Anatinus), Jean-Louis Dacheux, Francoise Dacheux, Valerie Labas, Heath Ecroyd, Brett Nixon, Russell C. Jones Dec 2011

New Proteins Identified In Epididymal Fluid From The Platypus (Ornithorhynchus Anatinus), Jean-Louis Dacheux, Francoise Dacheux, Valerie Labas, Heath Ecroyd, Brett Nixon, Russell C. Jones

Heath Ecroyd

The platypus epididymal proteome is being studied because epididymal proteins are essential for male fertility in mammals and it is considered that knowledge of the epididymal proteome in an early mammal would be informative in assessing the convergence and divergence of proteins that are important in the function of the mammalian epididymis. Few of the epididymal proteins that have been identified in eutherian mammals were found in platypus caudal epididymal fluid, and the major epididymal proteins in the platypus (PXN-FBPL, SPARC and E-OR20) have never been identified in the epididymis of any other mammal.


Mimicking Phosphorylation Of Alphab-Crystallin Affects Its Chaperone Activity, Heath W. Ecroyd, Sarah Meehan, J Horwitz, Andrew Aquilina, J L Benesch, C V Robinson, Cait Macphee, John Carver Dec 2011

Mimicking Phosphorylation Of Alphab-Crystallin Affects Its Chaperone Activity, Heath W. Ecroyd, Sarah Meehan, J Horwitz, Andrew Aquilina, J L Benesch, C V Robinson, Cait Macphee, John Carver

Heath Ecroyd

No abstract provided.


The Thioflavin T Fluorescence Assay For Amyloid Fibril Detection Can Be Biased By The Presence Of Exogenous Compounds, Sean A. Hudson, Heath Ecroyd, Tak W. Kee, John A. Carver Dec 2011

The Thioflavin T Fluorescence Assay For Amyloid Fibril Detection Can Be Biased By The Presence Of Exogenous Compounds, Sean A. Hudson, Heath Ecroyd, Tak W. Kee, John A. Carver

Heath Ecroyd

Thioflavin T (ThT) dye fluorescence is used regularly to quantify the formation and inhibition of amyloid fibrils in the presence of anti-amyloidogenic compounds such as polyphenols. However, in this study, it was shown, using three polyphenolics (curcumin, quercetin and resveratrol), that ThT fluorescence should be used with caution in the presence of such exogenous compounds. The strong absorptive and fluorescent properties of quercetin and curcumin were found to significantly bias the ThT fluorescence readings in both in situ real-time ThT assays and single time-point dilution ThT-type assays. The presence of curcumin at concentrations as low as 0.01 and 1 ...


Unraveling The Mysteries Of Protein Folding And Misfolding, Heath Ecroyd, John A. Carver Dec 2011

Unraveling The Mysteries Of Protein Folding And Misfolding, Heath Ecroyd, John A. Carver

Heath Ecroyd

This mini-review focuses on the processes and consequences of protein folding and misfolding. The latter process often leads to protein aggregation and precipitation with the aggregates adopting either highly ordered (amyloid fibril) or disordered (amorphous) forms. In particular, the amyloid fibril is discussed because this form has gained considerable notoriety due to its close links to a variety of debilitating diseases including Alzheimer's, Parkinson's, Huntington's, and Creutzfeldt-Jakob diseases, and type-II diabetes. In each of these diseases a different protein forms fibrils, yet the fibrils formed have a very similar structure. The mechanism by which fibrils form, fibril ...


Crystallin Proteins And Amyloid Fibrils, Heath Ecroyd, John A. Carver Dec 2011

Crystallin Proteins And Amyloid Fibrils, Heath Ecroyd, John A. Carver

Heath Ecroyd

Improper protein folding (misfolding) can lead to the formation of disordered (amorphous) or ordered (amyloid fibril) aggregates. The major lens protein, alpha-crystallin, is a member of the small heat-shock protein (sHsp) family of intracellular molecular chaperone proteins that prevent protein aggregation. Whilst the chaperone activity of sHsps against amorphously aggregating proteins has been well studied, its action against fibril-forming proteins has received less attention despite the presence of sHsps in deposits found in fibril-associated diseases (e.g. Alzheimer's and Parkinson's). In this review, the literature on the interaction of alpha B-crystallin and other sHsps with fibril-forming proteins is ...


Amyloid Fibril Formation By Bovine Milk Alpha(S2)-Casein Occurs Under Physiological Conditions Yet Is Prevented By Its Natural Counterpart, Alpha(S1)-Casein, David Thorn, Heath Ecroyd, M Sunde, Stephen Poon, John Carver Dec 2011

Amyloid Fibril Formation By Bovine Milk Alpha(S2)-Casein Occurs Under Physiological Conditions Yet Is Prevented By Its Natural Counterpart, Alpha(S1)-Casein, David Thorn, Heath Ecroyd, M Sunde, Stephen Poon, John Carver

Heath Ecroyd

The calcified proteinaceous deposits, or corpora amylacea, of bovine mammary tissue often comprise a network of amyloid fibrils, the origins of which have not been fully elucidated. Here, we demonstrate by transmission electron microscopy, dye binding assays, and X-ray fiber diffraction that bovine milk alpha(s2)-casein, a protein synthesized and secreted by mammary epithelial cells, readily forms fibrils in vitro. As a component of whole alpha(s)-casein, alpha(s2)-casein was separated from alpha(s1)-casein under nonreducing conditions via cation-exchange chromatography. Upon incubation at neutral pH and 37 degrees C, the spherical particles typical of alpha(s2 ...