Black Widow Spider

Latrodectus hesperus

Notorious for their bloodthirsty courtship, black widow spiders are identified by the colored markings on their black bodies.

Photograph by George Grall

Black widows are notorious spiders identified by the colored, hourglass-shaped mark on their abdomens. Several species answer to the name, and they are found in temperate regions around the world.

This spider's bite is much feared because its venom is reported to be 15 times stronger than a rattlesnake's. In humans, bites produce muscle aches, nausea, and a paralysis of the diaphragm that can make breathing difficult; however, contrary to popular belief, most people who are bitten suffer no serious damage—let alone death. But bites can be fatal—usually to small children, the elderly, or the infirm. Fortunately, fatalities are fairly rare; the spiders are nonaggressive and bite only in self-defense, such as when someone accidentally sits on them.

The animals most at risk from the black widow's bite are insects—and male black widow spiders. Females sometimes kill and eat their counterparts after mating in a macabre behavior that gave the insect its name. Black widows are solitary year-round except during this violent mating ritual.

These spiders spin large webs in which females suspend a cocoon with hundreds of eggs. Spiderlings disperse soon after they leave their eggs, but the web remains. Black widow spiders also use their webs to ensnare their prey, which consists of flies, mosquitoes, grasshoppers, beetles, and caterpillars. Black widows are comb-footed spiders, which means they have bristles on their hind legs that they use to cover their prey with silk once it has been trapped.

Find more here... http://animals.nationalgeographic.com/animals/bugs/black-widow-spider/

Novel Anti-Malarial Drug

Novel Anti-Malarial Drug Target Identified

ScienceDaily (July 19, 2012) — An international team of scientists, led by researchers from the Department of Pediatrics at the University of California, San Diego School of Medicine, have identified the first reported inhibitors of a key enzyme involved in survival of the parasite responsible for malaria.

This is an illustration of Anopheles darlingi. (Credit: UC San Diego School of Medicine)

Their findings, which may provide the basis for anti-malarial drug development, are currently published in the online version of the Journal of Medicinal Chemistry.

Tropical malaria is responsible for more than 1.2 million deaths annually. Severe forms of the disease are mainly caused by the parasite Plasmodium falciparum, transmitted to humans by female Anopheles mosquitoes. Malaria eradication has not been possible due to the lack of vaccines and the parasite's ability to develop resistance to most drugs.

The researchers conducted high-throughput screening of nearly 350,000 compounds in the National Institutes of Health's Molecular Libraries Small Molecule Repository (MLSMR) to identify compounds that inhibit an enzyme which plays an important role in parasite development: Plasmodium falciparumglucose-6-phosphate dehydrogenase (PfG6PD) is essential for proliferating and propagating P. falciparum.

"The enzyme G6PD catalyzes an initial step in a process that protects the malaria parasite from oxidative stress in red blood cells, creating an environment in which the parasite survives," said senior author Lars Bode, PhD, assistant professor in the UCSD Department of Pediatrics, Division of Neonatology and the Division of Gastroenterology, Hepatology and Nutrition. People with a natural deficiency in this enzyme are protected from malaria and its deadly symptoms, an observation that triggered the reported research.

The parasitic form of the enzyme (PfG6PD) is what contributes the majority of G6PD activity in infected red blood cells. Because the parasite lives in the blood of a malaria-infected person, the scientists aimed at identifying compounds that inhibit the parasitic form but not the human form of the enzyme. "We didn't want to interfere with the human form of the enzyme and risk potential side effects," Bode explained.

Scientific testing had previously been limited by a lack of recombinant PfG6PD. Team members in the lab of Katja Becker, PhD, at the Interdisciplinary Research Center at Justus-Liebig-University in Giessen, Germany produced the first complete and functional recombinant PfG6PD, and researchers led by Anthony Pinkerton, PhD, at Sanford-Burnham Medical Research Institute used it to identify the lead compound resulting from their efforts, ML276.

ML276 represents the first reported selective PfG6PD inhibitor, which stops the growth of malaria parasites in cultured red blood cells -- even those parasites that developed resistance to currently available drugs. "ML276 is a very promising basis for future drug design of new anti-malarial therapeutics," said Bode.

Story Source:

The above story is reprinted from materials provided byUniversity of California - San Diego, via Newswise.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Janina Preuss, Patrick Maloney, Satyamaheshwar Peddibhotla, Michael P Hedrick, Paul Hershberger, Palak Gosalia, Monika Milewski, Yujie Linda Li, Eliot Sugarman, Becky Hood, Eigo Suyama, Kevin Nguyen, Stefan Vasile, Eduard Sergienko, Arianna Mangravita-Novo, Michael Vicchiarelli, Danielle McAnally, Layton H Smith, Gregory P Roth, Jena Diwan, Thomas D.Y. Chung, Esther Jortzik, Stefan Rahlfs, Katja Becker, Anthony B. Pinkerton, Lars Bode. Discovery of aPlasmodium falciparumglucose-6-phosphate dehydrogenase 6-phosphogluconolactonase inhibitor (R,Z)-N-((1-ethylpyrrolidin-2-yl)methyl)-2-(2-fluorobenzylidene)-3-oxo-3,4-dihydro-2H-benzo[b][1,4]thiazine-6-carboxamide (ML276) that reduces parasit. Journal of Medicinal Chemistry, 2012; : 120719125855007 DOI:10.1021/jm300833h

link: http://www.sciencedaily.com/releases/2012/07/120719161859.htm

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