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2010

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Effects Of Prescribed Burning, Mechanical, And Chemical Treatments To Curtail Rhododendron Dominance And Reduce Urban Interface Fuel Loads, Shepard M. Zedaker, Charles W. Harrell Iii, Christopher D. Pearce Jan 2010

Effects Of Prescribed Burning, Mechanical, And Chemical Treatments To Curtail Rhododendron Dominance And Reduce Urban Interface Fuel Loads, Shepard M. Zedaker, Charles W. Harrell Iii, Christopher D. Pearce

Joint Fire Science Program Research Project Reports

One-half-acre treatment areas were delineated within prescribed burns. Cutting treatments consisted of chainsaw or brushsaw severing of all rhododendron stems within 6 in of the ground surface. Herbicide and herbicide followed by fire treatments consisted of basal applications of triclopyr or imazapyr in methylated seed oil on each plot. Cutting and burning treatments followed by herbicides utilized foliar applications of triclopyr or imazapyr in emulsions to all resprouting rhododendron. All herbicide plots were randomly split in half for the application of imazapyr or triclopyr on different halves. Analyses of variance and mean separation by LSD were used to compare treatment …

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Evaluating Postfire Seeding Treatments Designed To Suppress Cheatgrass (Bromus Tectorum) In A Ponderosa Pine Forest On The Colorado Plateau, Matthew L. Brooks, Robert Klinger, Jennifer Chase, Curt Deuser Jan 2010

Evaluating Postfire Seeding Treatments Designed To Suppress Cheatgrass (Bromus Tectorum) In A Ponderosa Pine Forest On The Colorado Plateau, Matthew L. Brooks, Robert Klinger, Jennifer Chase, Curt Deuser

Joint Fire Science Program Research Project Reports

The restoration of historical fuel conditions and fire regimes is one of the primary land management goals in the Shivwits Plateau region of northwestern Arizona. Fire is the primary tool used in this region to reduce fuel loads and shift landscapes back to historical conditions of a low intensity, 8- 15 year return interval, surface fire regime. However, the invasive plant cheatgrass has become the dominant understory vegetation and fuel type following initial fire treatments in many areas. There is significant concern that repeated burning at historically appropriate fire return intervals for ponderosa pine forest will benefit this invasive plant …

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Evaluating Approaches To Mapping Burn Probabilities For A Quantitative Wildland Fire Risk Analysis Framework., Carol Miller, Marc Parisien, Alan Ager, Mark Finney Jan 2010

Evaluating Approaches To Mapping Burn Probabilities For A Quantitative Wildland Fire Risk Analysis Framework., Carol Miller, Marc Parisien, Alan Ager, Mark Finney

Joint Fire Science Program Research Project Reports

This final report summarizes a collaboration that brought together experts in burn probability (BP) modeling and wildland fire risk analysis to compare and evaluate BP models, and ultimately incorporate these into a risk analysis framework. The project built on and extended the work from JFSP project #01-1-1-05. This project evaluated and tested three different independent models that generate BP maps as output for their operational use in risk analysis. The project quantified the relative sensitivity of the three BP models to different inputs, enhanced our understanding of the factors that affect BP at the landscape scale, and yielded concrete improvements …

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Evaluating Postfire Seeding Treatments Designed To Suppress Cheatgrass (Bromus Tectorum) In A Ponderosa Pine Forest On The Colorado Plateau, Matthew L. Brooks, Robert Klinger, Jennifer Chase, Curt Deuser Jan 2010

Evaluating Postfire Seeding Treatments Designed To Suppress Cheatgrass (Bromus Tectorum) In A Ponderosa Pine Forest On The Colorado Plateau, Matthew L. Brooks, Robert Klinger, Jennifer Chase, Curt Deuser

Joint Fire Science Program Research Project Reports

The restoration of historical fuel conditions and fire regimes is one of the primary land management goals in the Shivwits Plateau region of northwestern Arizona. Fire is the primary tool used in this region to reduce fuel loads and shift landscapes back to historical conditions of a low intensity, 8- 15 year return interval, surface fire regime. However, the invasive plant cheatgrass has become the dominant understory vegetation and fuel type following initial fire treatments in many areas. There is significant concern that repeated burning at historically appropriate fire return intervals for ponderosa pine forest will benefit this invasive plant …

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Modeling Whole-Tree Carbon Assimilation Rate Using Observed Transpiration Rates And Needle Sugar Carbon Isotope Ratios, Jia Hu, David J. P. Moore, Diego Andrés Riveros-Iregui, Sean P. Burns, Russell K. Monson Jan 2010

Modeling Whole-Tree Carbon Assimilation Rate Using Observed Transpiration Rates And Needle Sugar Carbon Isotope Ratios, Jia Hu, David J. P. Moore, Diego Andrés Riveros-Iregui, Sean P. Burns, Russell K. Monson

School of Natural Resources: Faculty Publications

• Understanding controls over plant–atmosphere CO2 exchange is important for quantifying carbon budgets across a range of spatial and temporal scales. In this study, we used a simple approach to estimate whole-tree CO2 assimilation rate (ATree) in a subalpine forest ecosystem.
• We analysed the carbon isotope ratio (δ13C) of extracted needle sugars and combined it with the daytime leaf-to-air vapor pressure deficit to estimate tree water-use efficiency (WUE). The estimated WUE was then combined with observations of tree transpiration rate (E) using sap flow techniques to estimate ATree. …

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A Continuous Measure Of Gross Primary Production For The Conterminous United States Derived From Modis And Ameriflux Data, Jingfeng Xiao, Qianlai Zhuang, Beverly E. Law, Jiquan Chen, Dennis D. Baldocchi, David R. Cook, Ram Oren, Andrew D. Richardson, Sonia Wharton, Siyan Ma, Timothy A. Martin, Shashi Verma, Andrew E. Suyker, Russell L. Scott, Russell K. Monson, Marcy Litvak, David Y. Hollinger, Ge Sun, Kenneth J. Davis, Paul Bolstad, Sean Burns, Peter S. Curtis, Bert G. Drake, Matthias Falk, Marc L. Fischer, David R. Foster, Lianhong Gu, Julian L. Hadley, Gabriel G. Katul, Roser Matamala, Steve Mcnulty, Tilden P. Meyers, J. William Munger, Asko Noormets, Walter Oechel, Kyaw Tha Paw U, Hans Peter Schmid, Gregory Starr, Margaret S. Torn, Steven C. Wofsy Jan 2010

A Continuous Measure Of Gross Primary Production For The Conterminous United States Derived From Modis And Ameriflux Data, Jingfeng Xiao, Qianlai Zhuang, Beverly E. Law, Jiquan Chen, Dennis D. Baldocchi, David R. Cook, Ram Oren, Andrew D. Richardson, Sonia Wharton, Siyan Ma, Timothy A. Martin, Shashi Verma, Andrew E. Suyker, Russell L. Scott, Russell K. Monson, Marcy Litvak, David Y. Hollinger, Ge Sun, Kenneth J. Davis, Paul Bolstad, Sean Burns, Peter S. Curtis, Bert G. Drake, Matthias Falk, Marc L. Fischer, David R. Foster, Lianhong Gu, Julian L. Hadley, Gabriel G. Katul, Roser Matamala, Steve Mcnulty, Tilden P. Meyers, J. William Munger, Asko Noormets, Walter Oechel, Kyaw Tha Paw U, Hans Peter Schmid, Gregory Starr, Margaret S. Torn, Steven C. Wofsy

School of Natural Resources: Faculty Publications

The quantification of carbon fluxes between the terrestrial biosphere and the atmosphere is of scientific importance and also relevant to climate-policy making. Eddy covariance flux towers provide continuous measurements of ecosystem-level exchange of carbon dioxide spanning diurnal, synoptic, seasonal, and interannual time scales. However, these measurements only represent the fluxes at the scale of the tower footprint. Here we used remotely sensed data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to upscale gross primary productivity (GPP) data from eddy covariance flux towers to the continental scale. We first combined GPP and MODIS data for 42 AmeriFlux towers encompassing a wide …

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The Leading Objective: January 2010, John C. Owens Jan 2010

The Leading Objective: January 2010, John C. Owens

Leading Object

Perspectives, Diffendal fund benefits Chinese students 25 years later, IGERT coordinator also leads fish and wildlife unit, University assistantship prompted Pohlman to go into laboratory work, IGERT award to prepare the way for addressing global water issues, Todd receives Omtvedt Innovation Award, Lefholtz receives outstanding service award, Alumnus retires after 22 years with AFBF, Welcome to Leading Object online edition, Four IANR employees receive OEA recognition.

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Suffolk University Newsletter (Sun), Vol. 36, No. 6, 2010, Suffolk University Office Of Public Affairs Jan 2010

Suffolk University Newsletter (Sun), Vol. 36, No. 6, 2010, Suffolk University Office Of Public Affairs

Suffolk University Newsletter (SUN)

No abstract provided.

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Homophobia, Heterosexism, And Ambivalence In The Premier Issue Of Sports Illustrated Woman/Sport, Lisa M. Weidman Jan 2010

Homophobia, Heterosexism, And Ambivalence In The Premier Issue Of Sports Illustrated Woman/Sport, Lisa M. Weidman

Faculty Publications

The arrival of a magazine dedicated solely to the world of women's sports was an exciting prospect for fans and proponents of women's sports. But the first issue of Sports Illustrated Women/Sport disappointed many who considered it did not put women's sports in the best possible light, who were worried and disappointed that its editors did not print the best stories or even focus on the most deserving athletes. Lisa Weidman decided to investigate further, using feminist theory and prior research findings to better understand the magazine's messages. Through a critical analysis of the magazine's editorial content - at the …

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2010-2011 - College Of Pharmacy Catalog, Office Of The Registrar, East Tennessee State University Jan 2010

2010-2011 - College Of Pharmacy Catalog, Office Of The Registrar, East Tennessee State University

Pharmacy Academic Catalogs

No abstract provided.

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Language Arts Achievement And Reading Instructional Strategies In Indiana Elementary Schools With High Percentages Of Increasing And Declining Enrollments, Maryanne B. Mcmahon Jan 2010

Language Arts Achievement And Reading Instructional Strategies In Indiana Elementary Schools With High Percentages Of Increasing And Declining Enrollments, Maryanne B. Mcmahon

All-Inclusive List of Electronic Theses and Dissertations

The focus of this quantitative study was to identify third grade ISTEP+ data from the top 10 increasing and declining enrollment public school districts in the state of Indiana to determine if communities experiencing high percentages of increasing or declining enrollments have significantly different achievement in language arts. This data was disaggregated to examine the subgroups of English Language Learners and Socio-economic Status. Additionally, the study determined if teachers in these schools were informed about scientific, research-based reading instructional strategies and to what degree SRBI was utilized in reading instruction to meet the needs of students. School corporations experiencing high …

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Extracellular Matrix Proteins: Implications For Angiogenesis, Kent Edward Williams Jan 2010

Extracellular Matrix Proteins: Implications For Angiogenesis, Kent Edward Williams

All-Inclusive List of Electronic Theses and Dissertations

The extracellular matrix (ECM) is an essential requirement for maintaining permanent shape and rigidity in multicellular organisms. The ECM serves two main functions: scaffolding and signaling. Insoluble collagen and soluble proteoglycans, glycosaminoglycans (GAGs), and glycoproteins allow for water retention and flexibility. The signaling role of the ECM is essential for a multitude of events including vascular development and angiogenesis. Via interactions with vascular endothelial cells, proteins of the ECM can induce or repress angiogenesis.

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Application Of Genefishing Discovery System On Differential Gene Expression Study For Prokaryotic System, Kek Heng Chua, H.C. Chai, Savithri Devi Puthucheary Jan 2010

Application Of Genefishing Discovery System On Differential Gene Expression Study For Prokaryotic System, Kek Heng Chua, H.C. Chai, Savithri Devi Puthucheary

Research Publications (2006 to 2010)

GeneFishing Discovery is a system applied on disease and gene related research for eukaryotes and the starting material for the study could be either total RNA or mRNA. In this study we demonstrate the use of this discovery system for a prokaryotic system by modifying the eukaryotic protocol using the poly (A)-tailing approach. As an example we compared the gene expression pattern of two closely related species of bacteria under the same family (Burkholderia thailandensis and Burkholderia cepacia) with satisfactory results.

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Challenges Associated With The Synthesis Of Unusual O-Carboxamido Stilbenes By The Heck Protocol: Intriguing Substituent Effects, Their Toxicological And Chemopreventive Implications, Azhar Ariffin, N.F. Thomas, C.H. Kee, K. Awang, K. Takeya, H. Morita, S.I. Hussain, K.M. Chan, J.F.F. Weber, P.J. Wood, M.D. Threadgill, C.G. Lim, S. Ng Jan 2010

Challenges Associated With The Synthesis Of Unusual O-Carboxamido Stilbenes By The Heck Protocol: Intriguing Substituent Effects, Their Toxicological And Chemopreventive Implications, Azhar Ariffin, N.F. Thomas, C.H. Kee, K. Awang, K. Takeya, H. Morita, S.I. Hussain, K.M. Chan, J.F.F. Weber, P.J. Wood, M.D. Threadgill, C.G. Lim, S. Ng

Research Publications (2006 to 2010)

The syntheses of fourteen unusual o-carboxamido stilbenes by the Heck protocol revealed surprising complexity related to intriguing substituent effects with mechanistic implications. The unexpected cytotoxic and chemopreventive properties also seem to be substituent dependent. For example, although stilbene 15d (with a 4-methoxy substituent) showed cytotoxicity on HT29 colon cancer cells with an IC50 of 4.9 mu M, the 3,4-dimethoxy derivative (15c) is inactive. It is interesting to observe that the 3,5-dimethoxy derivative (15e) showed remarkable chemopreventive activity in WRL-68 fetal hepatocytes, surpassing the gold standard, resveratrol. The resveratrol concentration needed to be 5 times higher than that of 15e to …

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Dibutyl{N '- 1-(5-Chloro-2-Oxidophenyl-Kappa O)Ethylidene -3-Hydroxy-2-Naphthohydrazidato-Kappa N-2 ',O-2}Tin(Iv), S.M. Lee, K.M. Lo, Hapipah Mohd Ali Jan 2010

Dibutyl{N '- 1-(5-Chloro-2-Oxidophenyl-Kappa O)Ethylidene -3-Hydroxy-2-Naphthohydrazidato-Kappa N-2 ',O-2}Tin(Iv), S.M. Lee, K.M. Lo, Hapipah Mohd Ali

Research Publications (2006 to 2010)

The five-coordinate SnIV atoms in the two crystallographically independent molecules of the title compound, [Sn(C4H9)2- (C19H13ClN2O3)], are in distorted cis-C2NO2Sn trigonalbipyramidal coordination environments. The tridentate dianion of the Schiff base, N0-[1-(5-chloro-2-oxidophenyl)- ethylidene]-3-hydroxy-2-naphthohydrazide, displays intermolecular O—H N hydrogen bonding, which stabilizes the overall compound.

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Early Growth And Survival Of Avicennia Alba Seedlings Under Excessive Sedimentation, N.A.M. Affandi, B. Kamali, R. Mz, N.M. Tamin, Roslan Hashim Jan 2010

Early Growth And Survival Of Avicennia Alba Seedlings Under Excessive Sedimentation, N.A.M. Affandi, B. Kamali, R. Mz, N.M. Tamin, Roslan Hashim

Research Publications (2006 to 2010)

A field study of growth and survival of Avicennia alba seedlings was conducted at a reforestation site where excessive sediment accretion resulted in seedling burial. A nearby natural habitat, where the sedimentation was not active, was also monitored as control plot. Seedlings height and number of leaves increments and survival rates have been measured monthly as indicators of the growth performance. Seedlings at both sites have similarly produced 2 leaves per month while seedlings at the reforestation site showed a significantly higher stem elongation compared to those in the natural habitat. Higher stem elongation rate in the reforestation site could …

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Enhanced Biodegradation Of Used Engine Oil In Soil Amended With Organic Wastes, P.O. Abioye, Abdul Aziz Abdul Raman, P. Agamuthu Jan 2010

Enhanced Biodegradation Of Used Engine Oil In Soil Amended With Organic Wastes, P.O. Abioye, Abdul Aziz Abdul Raman, P. Agamuthu

Research Publications (2006 to 2010)

Three organic wastes (banana skin (BS), brewery spent grain (BSG), and spent mushroom compost (SMC)) were used for bioremediation of soil spiked with used engine oil to determine the potential of these organic wastes in enhancing biodegradation of used oil in soil. The rates of biodegradation of the oil were studied for a period of 84 days under laboratory conditions. Hydrocarbon-utilizing bacterial counts were high in all the organic waste-amended soil ranging between 10.2 x 10(6) and 80.5 x 10(6) CFU/g compared to unamended control soil throughout the 84 days of study. Oil-contaminated soil amended with BSG showed the highest …

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Is F-2-Isoprostane A Biological Marker For The Early Onset Of Type 2 Diabetes Mellitus?, Subramanian Kaviarasan, Sekaran Muniandy, Rajes Qvist, Karuthan Chinna, Ikram Shah Ismail Jan 2010

Is F-2-Isoprostane A Biological Marker For The Early Onset Of Type 2 Diabetes Mellitus?, Subramanian Kaviarasan, Sekaran Muniandy, Rajes Qvist, Karuthan Chinna, Ikram Shah Ismail

Research Publications (2006 to 2010)

Aim: This clinical study was undertaken to investigate whether F-2-isoprostane, a prostaglandin F-2-like compound derived from the non-enzymatic peroxidation of arachidonic acid, could serve as a novel biomarker for early detection of type 2 diabetes mellitus (T2DM) or its complications. Materials and Methods: Twenty-five individuals who had impaired glucose tolerance (IGT) or T2DM were compared with controls. Anthropometry, plasma glucose, hemoglobin A1c, lipid profile and F-2-isoprostane levels were measured in these subjects. Results: Clinical characteristics of subjects with IGT showed significant alteration when compared to subjects with T2DM but not with that of controls having normal glucose tolerance. In the …

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Life Cycle Impact Assessment (Lcia) Using Traci Methodology: An Analysis Of Potential Impact On Potable Water Production, Amir Hamzah Sharaai, Noor Zalina Mahmood, Abdul Halim Sulaiman Jan 2010

Life Cycle Impact Assessment (Lcia) Using Traci Methodology: An Analysis Of Potential Impact On Potable Water Production, Amir Hamzah Sharaai, Noor Zalina Mahmood, Abdul Halim Sulaiman

Research Publications (2006 to 2010)

Life cycle assessment (LCA) is a method to analyse a particular product or service. It begins with the process of extraction until the product is exhausted by 'cradle-to-grave' analysis. The LCA includes establishment of an inventory, that is all types of emissions and also waste products. After that, this inventory would be translated or transformed to show the impact on environment in the life cycle impact assessment (LCIA). Two LCIA methods has been accepted such as Midpoint and Endpoint approach. TRACI is one method that uses Midpoint approach. From the analysis on the two stages of potable water production, that …

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Necrotising Fasciitis Of The Lower Limb Caused By Community-Acquired Methicillin-Resistant Staphylococcus Aureus, C.K. Chan, A.M. Merican, A.M. Nawar, Y.A. Hanifah, Kwai Lin Thong Jan 2010

Necrotising Fasciitis Of The Lower Limb Caused By Community-Acquired Methicillin-Resistant Staphylococcus Aureus, C.K. Chan, A.M. Merican, A.M. Nawar, Y.A. Hanifah, Kwai Lin Thong

Research Publications (2006 to 2010)

Necrotising fasciitis caused by Community-Acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a new entity. Although it is recognised worldwide, there have been no reported cases to date in Malaysia. We report a case of necrotising fasciitis of the left lower limb in an otherwise healthy 20-year-old man. He presented with septic shock and despite the paucity of clinical signs in the limb, the infection was aggressive. Methicillin-Resistant Staphylococcus aureus (MRSA) was isolated from the deep fascia of the leg. Panton-Valentine leucocidin gene (PVL), which is a stable genetic marker for CA-MRSA strain, was positive in this case. This case …

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Office Of The Vice Provost For Research Annual Report - 2010, Office Of The Vice Provost For Research, East Tennessee State University Jan 2010

Office Of The Vice Provost For Research Annual Report - 2010, Office Of The Vice Provost For Research, East Tennessee State University

Annual Reports

No abstract provided.

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Open Access Repositories And Journals For Visibility: Implications For Malaysian Libraries, A.N. Zainab Jan 2010

Open Access Repositories And Journals For Visibility: Implications For Malaysian Libraries, A.N. Zainab

Research Publications (2006 to 2010)

This paper describes the growth of Open Access (OA) repositories and journals as reported by monitoring initiatives such as ROAR (Registry of Open Access Repositories), Open DOAR (Open Directory of Open Access Repositories), DOAJ (Directory of Open Access Journals), Directory of Web Ranking of World Repositories by the Cybermetrics Laboratory in Spain and published literature. The performance of Malaysian OA repositories and journals is highlighted. The strength of OA channels in increasing visibility and citations are evidenced by research findings. It is proposed that libraries champion OA initiatives by making university or institutional governance aware; encouraging institutional journal publishers to …

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Paraoxonase 1 Activity As A Predictor Of Cardiovascular Disease In Type 2 Diabetes, R. Poh, S. Muniandy Jan 2010

Paraoxonase 1 Activity As A Predictor Of Cardiovascular Disease In Type 2 Diabetes, R. Poh, S. Muniandy

Research Publications (2006 to 2010)

The role of paraoxonase 1 in cardiovascular disease complications in type 2 diabetes mellitus is not fully understood. We studied paraoxonase activity towards paraoxon in 188 non-diabetic and 140 diabetic subjects using general linear models and univariate analysis. Adjusting for age revealed a reduction in activity towards paraoxon was associated with a significant increase in risk (p=0.023) for cardiovascular disease complications in diabetic patients. Multivariate analysis of two plasma measures of paraoxonase activity using paraoxon and diazoxon also showed reduced paraoxonase activity towards paraoxon was associated with a significant increase in risk (p=0.045) for cardiovascular disease complications in diabetic patients. …

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Book Panel Response: Symposium On Ladelle Mcwhorter's Racism And Sexual Oppression In Anglo-America: A Genealogy, Ladelle Mcwhorter Jan 2010

Book Panel Response: Symposium On Ladelle Mcwhorter's Racism And Sexual Oppression In Anglo-America: A Genealogy, Ladelle Mcwhorter

Philosophy Faculty Publications

Unfortunately I do not have space to address individually each issue these four papers raise. Instead, I will first situate my work in relation to identity politics and address fears that my approach is reductive. Then, building on comments from Professors Wilkerson and Al-Saji, I will offer some remarks about aims, methods, and shortcomings.

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What If We Were Equal: A Mississippi Health Assessment, Arthur G. Cosby, Warren A. Jones, Lindsay B. Jones, Sangeetha Shivaji, Robert E. Greenberg, Colleen Mckee, Tara Morgan, Emily Nations, Tonya T. Neaves, Elliot Welford, Bailey Smith Jan 2010

What If We Were Equal: A Mississippi Health Assessment, Arthur G. Cosby, Warren A. Jones, Lindsay B. Jones, Sangeetha Shivaji, Robert E. Greenberg, Colleen Mckee, Tara Morgan, Emily Nations, Tonya T. Neaves, Elliot Welford, Bailey Smith

SSRC Publications

Mississippi has become a poster child for many of the societal problems affecting the disadvantaged of our nation. Of the challenges facing Mississippi, none are more important than the problems of health and health care pervading our population.

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Activity Analysis Of The Fragile X Mental Retardation Protein Isoforms 1, 2 And 3: Recombinant Bacterial Expression And Purification With Subsequent Quantitative Analysis Of Binding To In Vivo Target G Quadruplex Forming Ribonucleaic Acids And Regulation Of Translation, Timothy Lee Evans Jan 2010

Activity Analysis Of The Fragile X Mental Retardation Protein Isoforms 1, 2 And 3: Recombinant Bacterial Expression And Purification With Subsequent Quantitative Analysis Of Binding To In Vivo Target G Quadruplex Forming Ribonucleaic Acids And Regulation Of Translation, Timothy Lee Evans

Electronic Theses and Dissertations

The loss of expression of the fragile X mental retardation protein (FMRP) leads to fragile X syndrome. Fragile X syndrome is the most prevalent inheritable mental retardation. FMRP has two types of RNA binding domains, two K-homology domains and an arginine-glycine-glycine box domain, and is proposed to act as a translation regulator of specific mRNA. Despite extensive research, the mechanism by which FMRP loss leads to the fragile X syndrome remains unclear. Thus, there is high interest to produce sufficient quantities of pure recombinant FMRP for biochemical and biophysical studies of the protein function. However, the recombinant bacterial expression of …

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Ph-(Low)-Insertion-Peptide (Phlip) Translocation Of Membrane Impermeable Phalloidin Toxin Inhibits Cancer Cell Proliferation, Ming An, Dayanjali Wijesinghe, Oleg A. Andreev, Yana K. Reshetnyak, Donald M. Engelman Jan 2010

Ph-(Low)-Insertion-Peptide (Phlip) Translocation Of Membrane Impermeable Phalloidin Toxin Inhibits Cancer Cell Proliferation, Ming An, Dayanjali Wijesinghe, Oleg A. Andreev, Yana K. Reshetnyak, Donald M. Engelman

Physics Faculty Publications

We find that pH-(low)-insertion-peptide (pHLIP)-facilitated translocation of phalloidin, a cell-impermeable polar toxin, inhibits the proliferation of cancer cells in a pH-dependent fashion. The monomeric pHLIP inserts its C terminus across a membrane under slightly acidic conditions (pH 6–6.5), forming a transmembrane helix. The delivery construct carries phalloidin linked to its inserting C terminus via a disulfide bond that is cleaved inside cells, releasing the toxin. To facilitate delivery of the polar agent, a lipophilic rhodamine moiety is also attached to the inserting end of pHLIP. After a 3 h incubation at pH 6.1–6.2 with 2–4 μM concentrations of the …

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Ph (Low) Insertion Peptide (Phlip) Inserts Across A Lipid Bilayer As A Helix And Exits By A Different Path, Oleg A. Andreev, Alexander G. Karabadzhak, Dhammika Weerakkody, Gregory O. Andreev, Donald M. Engelman, Yana K. Reshetnyak Jan 2010

Ph (Low) Insertion Peptide (Phlip) Inserts Across A Lipid Bilayer As A Helix And Exits By A Different Path, Oleg A. Andreev, Alexander G. Karabadzhak, Dhammika Weerakkody, Gregory O. Andreev, Donald M. Engelman, Yana K. Reshetnyak

Physics Faculty Publications

What are the molecular events that occur when a peptide inserts across a membrane or exits from it? Using the pH-triggered insertion of the pH low insertion peptide to enable kinetic analysis, we show that insertion occurs in several steps, with rapid (0.1 sec) interfacial helix formation, followed by a much slower (100 sec) insertion pathway to give a transmembrane helix. The reverse process of unfolding and peptide exit from the bilayer core, which can be induced by a rapid rise of the pH from acidic to basic, proceeds approximately 400 times faster than folding/insertion and through different intermediate states. …

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Ph-Sensitive Membrane Peptides (Phlips) As A Novel Class Of Delivery Agents, Oleg A. Andreev, Donald M. Engelman, Yana K. Reshetnyak Jan 2010

Ph-Sensitive Membrane Peptides (Phlips) As A Novel Class Of Delivery Agents, Oleg A. Andreev, Donald M. Engelman, Yana K. Reshetnyak

Physics Faculty Publications

Here we review a novel class of delivery vehicles based on pH-sensitive, moderately polar membrane peptides, which we call pH (Low) Insertion Peptides (pHLIPs), that target cells located in the acidic environment found in many diseased tissues, including tumours. Acidity targeting by pHLIPs is achieved as a result of helix formation and transmembrane insertion. In contrast to the earlier technologies based on cell-penetrating peptides, pHLIPs act as monomeric membrane-inserting peptides that translocate one terminus across a membrane into the cytoplasm, while the other terminus remains in the extracellular space, locating the peptide in the membrane lipid bilayer. Therefore pHLIP has …

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Tuning The Insertion Properties Of Phlip, Monka Musial-Siwek, Alexander Karabadzhak, Oleg A. Andreev, Yana K. Reshetnyak, Donald M. Engelman Jan 2010

Tuning The Insertion Properties Of Phlip, Monka Musial-Siwek, Alexander Karabadzhak, Oleg A. Andreev, Yana K. Reshetnyak, Donald M. Engelman

Physics Faculty Publications

The pH (low) insertion peptide (pHLIP) has exceptional characteristics: at neutral pH it is an unstructured monomer in solution or when bound to lipid bilayer surfaces, and it inserts across a lipid bilayer as a monomeric alpha-helix at acidic pH. The peptide targets acidic tissues in vivo and may be useful in cancer biology for delivery of imaging or therapeutic molecules to acidic tumors. To find ways to vary its useful properties, we have designed and analyzed pHLIP sequence variants. We find that each of the Asp residues in the transmembrane segment is critical for solubility and pH-dependent membrane insertion …

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