Immunology and Infectious Disease Commons^™

Mutation In The Plasmodium Falciparum Crt Protein Determines The Stereospecific Activity Of Antimalarial Cinchona Alkaloids, Carol E. Griffin, Jonathan M. Hoke, Upeka Samarakoon, Junhui Duan, Jianbing Mu, Michael T. Ferdig, David C. Warhurst, Roland Cooper

Roland A. Cooper

The Cinchona alkaloids are quinoline aminoalcohols that occur as diastereomer pairs, typified by (-)-quinine and (+)-quinidine. The potency of (+)-isomers is greater than the (-)-isomers in vitro and in vivo against Plasmodium falciparum malaria parasites. They may act by the inhibition of heme crystallization within the parasite digestive vacuole in a manner similar to chloroquine. Earlier studies showed that a K76I mutation in the digestive vacuole-associated protein, PfCRT (P. falciparum chloroquine resistance transporter), reversed the normal potency order of quinine and quinidine toward P. falciparum. To further explore PfCRT-alkaloid interactions in the malaria parasite, we measured the in vitro susceptibility …

Accumulation Of Artemisinin Trioxane Derivatives Within Neutral Lipids Of Plasmodium Falciparum Malaria Parasites Is Endoperoxide-Dependent, Carmony L. Hartwig, Andrew S. Rosenthal, John D'Angelo, Carol E. Griffin, Gary H. Posner, Roland A. Cooper

Roland A. Cooper

The antimalarial trioxanes, exemplified by the naturally occurring sesquiterpene lactone artemisinin and its semi-synthetic derivatives, contain an endoperoxide pharmacophore that lends tremendous potency against Plasmodium parasites. Despite decades of research, their mechanism of action remains unresolved. A leading model of anti-plasmodial activity hypothesizes that iron-mediated cleavage of the endoperoxide bridge generates cytotoxic drug metabolites capable of damaging cellular macromolecules. To probe the malarial targets of the endoperoxide drugs, we studied the distribution of fluorescent dansyl trioxane derivatives in living, intraerythrocytic-stage Plasmodium falciparum parasites using microscopic imaging. The fluorescent trioxanes rapidly accumulated in parasitized erythrocytes, localizing within digestive vacuole-associated neutral lipid …

Genome-Wide Compensatory Changes Accompany Drugselected Mutations In The Plasmodium Falciparum Crt Gene, Hongying Jiang, Jigar J. Patel, Ming Yi, Jianbing Mu, Jinhui Ding, Robert Stephens, Roland Cooper, Michael T. Ferdig, Xin-Zhuan Su

Roland A. Cooper

Mutations in PfCRT (Plasmodium falciparum chloroquine-resistant transporter), particularly the substitution at amino acid position 76, confer chloroquine (CQ) resistance in P. falciparum. Point mutations in the homolog of the mammalian multidrug resistance gene (pfmdr1) can also modulate the levels of CQ response. Moreover, parasites with the same pfcrt and pfmdr1 alleles exhibit a wide range of drug sensitivity, suggesting that additional genes contribute to levels of CQ resistance (CQR). Reemergence of CQ sensitive parasites after cessation of CQ use indicates that changes in PfCRT are deleterious to the parasite. Some CQR parasites, however, persist in the field and grow well …

Design, Synthesis, And Evaluation Of 10-N-Substituted Acridones As Novel Chemosensitizers In Plasmodium Falciparum, Jane X. Kelly, Martin J. Smilkstein, Roland A. Cooper, Kristin D. Lane, Robert A. Johnson, Aaron Janowsky, Rozalia A. Dodean, Rolf Winter, Michael Riscoe

Roland A. Cooper

A series of novel 10-N-substituted acridones, bearing alkyl side chains with tertiary amine groups at the terminal position, were designed, synthesized, and evaluated for the ability to enhance the potency of quinoline drugs against multidrug-resistant (MDR) Plasmodium falciparum malaria parasites. A number of acridone derivatives, with side chains bridged three or more carbon atoms apart between the ring nitrogen and terminal nitrogen, demonstrated chloroquine (CQ)-chemosensitizing activity against the MDR strain of P. falciparum (Dd2). Isobologram analysis revealed that selected candidates demonstrated significant synergy with CQ in the CQ-resistant (CQR) parasite Dd2 but only additive (or indifferent) interaction in the CQ-sensitive …

Detection Of Panulirus Argus Virus 1 (Pav1) In The Caribbean Spiny Lobster Using Fluorescence In Situ Hybridization (Fish), Caiwen Li, Jeffrey D. Shields, Hamish J. Small, Kimberly S. Reece, Carmony L. Hartwig, Roland A. Cooper, Robert E. Ratzlaff

Roland A. Cooper

Panulirus argus Virus 1 (PaV1) is the first virus known to be pathogenic to a wild lobster. It infects the Caribbean spiny lobster P. argus from the Florida Keys, and has a predilection for juveniles. The monitoring of the virus in wild populations and study of its behavior in the laboratory require the development of reliable diagnostic tools. A sensitive and specific fluorescence in situ hybridization (FISH) assay was developed for detection of PaV1. The lower detection limit using a 110 bp DNA probe in a dot-blot hybridization for PaV1 DNA was 10 pg of cloned template PaV1 DNA and …

Topical Lipophilic Epigallocatechin-3-Gallate On Herpes Labialis: A Phase Ii Clinical Trial Of Averteax Formula, Man Zhao, Rong Zheng, Jinyan Jiang, Douglas Dickinson, Baiping Fu, Tin-Chun Chu, Lee Lee, Hanna Pearl, Stephen Hsu

Tin-Chun Chu, Ph.D.

Objectives The aim of this study was to clinically evaluate a topical proprietary formulation containing lipophilic catechins (AverTeaX) on recurrent herpes labialis. Methods A double blind, placebo-controlled, randomized trial with 40 participants initially in two groups. Results Compared to the vehicle group, AverTeaX applied topically 6-8 times daily resulted in a significant reduction of clinical episode duration (median 4.5 days, range 1-11 days vs. 9 days, range 2-11 days, p=0.003) and shortened blistering/ulceration stages within an episode from a median of 3 (range 0-6) days to 1 (range 0-3) day (p=0.0003). Median quality of life scores based on a multi-question …

Preliminary Evaluation Of Near Infrared Spectroscopy As A Method To Detect Plasma Leakage In Children With Dengue Hemorrhagic Fever, Babs R. Soller, Anon Srikiatkhachorn, Fengmei Zou, Alan L. Rothman, In-Kyu Yoon, Robert V. Gibbons, Siripen Kalayanarooj, Stephen J. Thomas, Sharone Green

Sharone Green

BACKGROUND: Dengue viral infections are prevalent in the tropical and sub-tropical regions of the world, resulting in substantial morbidity and mortality. Clinical manifestations range from a self-limited fever to a potential life-threatening plasma leakage syndrome (dengue hemorrhagic fever). The objective of this study was to assess the utility of near infrared spectroscopy (NIRS) measurements of muscle oxygen saturation (SmO2) as a possible continuous measure to detect plasma leakage in children with dengue.

METHODS: Children ages 6 months to 15 years of age admitted with suspected dengue were enrolled from the dengue ward at Queen Sirikit National Institute for Child Health. …

Positive Selection Drives Preferred Segment Combinations During Influenza Virus Reassortment, Konstantin Zeldovich, Ping Liu, Nicholas Renzette, Matthieu Foll, Serena Pham, Sergey Venev, Glen Gallagher, Daniel Bolon, Evelyn Kurt-Jones, Jeffrey Jensen, Daniel Caffrey, Celia Schiffer, Timothy Kowalik, Jennifer Wang, Robert Finberg

Celia A. Schiffer

Influenza A virus (IAV) has a segmented genome that allows for the exchange of genome segments between different strains. This reassortment accelerates evolution by breaking linkage, helping IAV cross species barriers to potentially create highly virulent strains. Challenges associated with monitoring the process of reassortment in molecular detail have limited our understanding of its evolutionary implications. We applied a novel deep sequencing approach with quantitative analysis to assess the in vitro temporal evolution of genomic reassortment in IAV. The combination of H1N1 and H3N2 strains reproducibly generated a new H1N2 strain with the hemagglutinin and nucleoprotein segments originating from H1N1 …

Human Sewage Identified As Likely Source Of White Pox Disease Of The Threatened Caribbean Elkhorn Coral, Kathryn Sutherland, James Porter, Jeffrey Turner, Brian Thomas, Erin Looney, Trevor Luna, Meredith Meyers, J. Futch, Erin Lipp

Kathryn Patterson Sutherland PhD

Caribbean elkhorn coral, Acropora palmata, has been decimated in recent years, resulting in the listing of this species as threatened under the United States Endangered Species Act. A major contributing factor in the decline of this iconic species is white pox disease. In 2002, we identified the faecal enterobacterium, Serratia marcescens, as an etiological agent for white pox. During outbreaks in 2003 a unique strain of S. marcescens was identified in both human sewage and white pox lesions. This strain (PDR60) was also identified from corallivorious snails (Coralliophila abbreviata), reef water, and two non-acroporid coral species, Siderastrea siderea and Solenastrea …

Antiviral Activity Of Theaflavin Digallate Against Herpes Simplex Virus Type 1, Aline De Oliveira, Derek Prince, Chih-Yu Lo, Lee Lee, Tin-Chun Chu

Tin-Chun Chu, Ph.D.

Tea is the second most consumed drink in the world. The beneficial effects of tea have been mostly attributed to its catechin content. Black tea is derived from the leaves of Camellia sinensis plant, and it is rich in theaflavin polyphenols, in particular theaflavin (TF1), theaflavin-3-monogallate (TF2A), theaflavin-3′-monogallate (TF2B), and theaflavin-3,3′-digallate (TF3). Vero and A549 cells were used to evaluate the effect of purified individual black tea theaflavins as anti-herpes simplex virus 1 agents. With the rise of HSV resistant strains, there is a critical need to develop novel antiherpesviral treatments. Results of the cytotoxicity assay tested by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium] …

Hiv-1 Protease-Substrate Coevolution In Nelfinavir Resistance, Madhavi Kolli, Aysegul Ozen, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

Resistance to various human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) challenges the effectiveness of therapies in treating HIV-1-infected individuals and AIDS patients. The virus accumulates mutations within the protease (PR) that render the PIs less potent. Occasionally, Gag sequences also coevolve with mutations at PR cleavage sites contributing to drug resistance. In this study, we investigated the structural basis of coevolution of the p1-p6 cleavage site with the nelfinavir (NFV) resistance D30N/N88D protease mutations by determining crystal structures of wild-type and NFV-resistant HIV-1 protease in complex with p1-p6 substrate peptide variants with L449F and/or S451N. Alterations of residue …