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 A free newsletter, sent 6 times a year, focusing on the evolution of infectious diseases from emerging infectious diseases, host-pathogen interactions and the impact of genomics to the evolution of drug resistance |
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| Imperfect vaccines and
imperfect models themes and variations A recent Science paper by Gordon et al. presents a model for how leaky vaccines can lead to evolutionary changes in the virulence of parasites. Whilst readers of some of the press reaction to this paper might be forgiven for thinking that it referred to certainties about actual malaria vaccines, there are currently no malaria vaccines beyond the early clinical trial phase, so the paper could in principle offer no more than theoretical predictions. The models might well be less appropriate for the chosen example of Plasmodium falciparum malaria than for other parasites. Critical review of the Gandon et al. paper highlights both the fact that the determinants of virulence in malaria are not well understood, and that monitoring of malaria vaccines should consider more than just the immediate effects on vaccine efficacy. From: Trends in Ecology & Evolution, 2002, 17: 154-156  FREE
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| Units of biodiversity Darwin's Origin of Species was published 140 years ago, but we still do not really know what a species is - there is no generally applicable definition. Are we trying to define something that does not exist? Species diagniosis is particularly important in the field of parasite research. In parasites, there is a strong potential for genetic variability and biodiversity. Sympatric speciation, clonal reproduction, selfing, sib mating and parthenogenesis all contribute to the evolution of the gene pool diversities in parasites, making this an intriguing topic. From: Trends in Parasitology, 2002, 18:121-124 FREE
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| The PE multigene family: a
'molecular mantra' for mycobacteria The PE multigene family of Mycobacterium tuberculosis is remarkable in that it is composed of approximately 100 highly related genes that are found only in mycobacteria. Early evidence suggests that proteins encoded by certain members of this gene family could be present in the mycobacterial cell wall, impact antigen-presentation pathways and the ensuing host immune responses, and also provide a mechanism for generating antigenic diversity in mycobacteria. Molecular analysis of the individual proteins will be difficult. Nevertheless, the rewards resulting from investigation of this unique family of genes are certain to compensate for the trouble, especially if they lead to novel interventions for controlling and treating mycobacterial infections and diseases such as TB. From: Trends in Microbiology, 2002, 10:246-249 FREE
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| Enhanceosomes The enhanceosome is a powerful transcriptional activation machine that controls specificity of gene expression. The molecular switch triggering the assembly of the best studied enchancesome, that of interferon-beta, is the high mobility group protein HMG I(Y), which binds to 4 sites in the enhancer and unbends DNA. This allows a network of protein-protein interactions to take place, resulting in the cooperative assembly of the enhanceosome. This stable complex forms a unique activating surface that can initiate a programme of transcription with remarkable precision. From: Current Opinion in Genetics and Development, 2001, 11:2:205-208 FREE
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| How to access full text * Abstracts are free to all users. Full text is available in BioMedNet Reviews - the world's largest life science reviews database. Ask your librarian to subscribe, or to register for an institutional trial. |
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| Dengue strains vaccine
development The virus that causes epidemics of dengue fever in south-east Asia and central America evolves new strains so rapidly that an effective vaccine is many years away, Vincent Chow, associate professor in molecular genetics at the National University of Singapore, warned delegates at ICID 2002 this March. Although four main types of the virus, which is transmitted by the mosquito Aedes aegypti, are found in all parts of the world, there are dozens of different strains, within each serotype, that show more regional variation. Chow's team is now revealing the impact that such variations might have on the effectiveness of vaccines for the disease, which infects as many as 60 million people each year. "A vaccine that works against certain strains may not be useful against new strains that may emerge in the future," Chow said. "From [our] molecular work, they are emerging very quickly." From: BioMedNet Conference Reporter FREE
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| How do bacteria resist
human antimicrobial peptides? Cationic antimicrobial peptides (CAMPs), such as defensins, cathelicidins and thrombocidins, are an important human defense mechanism, protecting skin and epithelia against invading microorganisms. These host defense peptides are widely distributed in animals and plants and are among the most ancient of host defense factors. Not suprisingly, many bacterial pathogens have evolved countermeasures to limit the effectiveness of this component of the host immune system and many mechanisms of resistance to CAMPs reflect the same molecular strategy. The common theme in CAMP resistance in bacteria is reduction of the negative surface charge of the bacterial cell envelope with positively charged substituents, thus minimizing the potential for interaction with the positively charged peptides. From: Trends in Microbiology, 2002, 10:179-186 FREE
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< < ADVERTISEMENT > > Every month THE LANCET INFECTIOUS DISEASES delivers insightful expert reviews and timely global news on the important topics in infectious diseases. For more information, or to subscribe, visit us online at http://infection.thelancet.com. |
Unmet need in infectious
disease research: social science Despite
the consensus that numerous social factors contribute to the global
spread of infectious disease, the field still suffers from a dearth of
important social-science information, Jonathan Mayer, a geographer at
the University of Washington, said at the US National Academies of
Sciences (NAS) Institute of Medicine's forum on emerging infections. At
the meeting, he spoke on how the dynamics of vector-borne disease are
changing with increased globalization, and that understanding these
dynamics requires us to unify vector and human ecology. "We need to look
at population movements, organization, behaviours and culture," he said.
From: BioMedNet News and Comment FREE
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| Old diseases never die (or
fade away) This article reviews the status of Chagas disease in Amazonian Brazil, including known reservoirs and vectors, and the genetic diversity of the c ausative agent, Trypanosoma cruzi, which has a great capacity for genetic exchange. Infection in Amazonian Brazil is enzootic, involving a variety of wild mammals and at least ten of the triotamine bug species that acts as vector. Numbers of human cases of this disease are increasing, and this health problem continues to challenge disease control authorities in this region. From: Trends in Parasitology, 2002, 18:171-176 FREE
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