Parasitology today (Personal ed.)最新文献

Plasmodium, the causative agent of malaria, has many morphologically and functionally distinct developmental stages. In the mosquito host alone, there are five transitions during the development of a gametocyte into a sporozoite. Determining which genes are expressed at the different developmental stages is vital to our understanding of the parasite. There are a growing number of techniques designed to study gene expression, including microarray. Here, Johannes Dessens, Gabrielle Margos, Maria del Carmen Rodriguez and Robert Sinden describe a novel method: suppression subtractive hybridization (SSH) and its successful application in obtaining mosquito midgut stage-specific genes of Plasmodium.

The amplified restriction fragment length polymorphism (AFLP) technique is a relatively new method for the analysis of polymorphism that has not yet been widely used in parasitology. In this article, Dan Masiga, Andy Tait and Mike Turner provide a brief introduction to AFLP and illustrate how it can be used in the investigation of marker inheritance in genetic crosses and in the analysis of polymorphism of field populations. They also briefly highlight the strengths and weaknesses of AFLP in comparison with other methods for detecting polymorphism and conclude that AFLP is a very useful addition to the range of techniques available.

Lymphatic filariasis caused by Wuchereria bancrofti and Brugia malayi is endemic throughout most of the southern half of the Philippine archipelago. Economic and manpower shortages prior to 1996 made it difficult to acquire new prevalence data and vector control data concurrently from all provinces. Nevertheless, analysis of cumulative prevalence data on filariasis indicates the persistence of filariasis in each of the three major island groups – Luzon, Visayas and Mindanao – including 45 out of 77 provinces. Here, Michael Kron and colleagues summarize the prevalence data, and review host, parasite and vector characteristics relevant to the design and implementation of disease control initiatives in the Philippines planned for the year 2000.

Gene discovery programs centred around expressed sequence tag (EST) and genome sequencing projects have predictably led to an exponential surge in the number of parasite gene sequences deposited in public databases. To take advantage of this wealth of sequence information, it is essential to develop rapid methods for elucidating the biological function or mode of action of individual genes. Here, Patricia Kuwabara and Alan Coulson discuss the virtues of a powerful epigenetic gene disruption technique, RNA-mediated interference (RNAi), which was originally developed for the nematode Caenorhabditis elegans. It is anticipated that this technique will not only provide insights into gene function, but also help investigators to mine the genome for candidate drug intervention or vaccine development targets, some of which may not be readily apparent on the basis of sequence information alone.

C-type lectins (C-TLs) are a family of carbohydrate-binding proteins intimately involved in diverse processes including vertebrate immune cell signalling and trafficking, activation of innate immunity in both vertebrates and invertebrates, and venom-induced haemostasis. Helminth C-TLs sharing sequence and structural similarity with mammalian immune cell lectins have recently been identified from nematode parasites, suggesting clear roles for these proteins at the host–parasite interface, notably in immune evasion. Here, Alex Loukas and Rick Maizels review the status of helminth lectin research and suggest ways in which parasitic worms might utilize C-TLs during their life history.