An Atlas for Schistosoma mansoni Organs and Life-Cycle Stages Using Cell Type-Specific Markers and Confocal Microscopy

Schistosomiasis (bilharzia) is a tropical disease caused by trematode parasites (Schistosoma) that affects hundreds of millions of people in the developing world. Currently only a single drug (praziquantel) is available to treat this disease, highlighting the importance of developing new techniques to study Schistosoma. While molecular advances, including RNA interference and the availability of complete genome sequences for two Schistosoma species, will help to revolutionize studies of these animals, an array of tools for visualizing the consequences of experimental perturbations on tissue integrity and development needs to be made widely available. To this end, we screened a battery of commercially available stains, antibodies and fluorescently labeled lectins, many of which have not been described previously for analyzing schistosomes, for their ability to label various cell and tissue types in the cercarial stage of S. mansoni. This analysis uncovered more than 20 new markers that label most cercarial tissues, including the tegument, the musculature, the protonephridia, the secretory system and the nervous system. Using these markers we present a high-resolution visual depiction of cercarial anatomy. Examining the effectiveness of a subset of these markers in S. mansoni adults and miracidia, we demonstrate the value of these tools for labeling tissues in a variety of life-cycle stages. The methodologies described here will facilitate functional analyses aimed at understanding fundamental biological processes in these parasites

Skeletal muscle oxidative capacity in rats fed high-fat diet.

To investigate whether young rats respond to high-fat feeding through changes in energy efficiency and fuel partitioning at the level of skeletal muscle, to avoid obesity development. In addition, to establish whether the two mitochondrial subpopulations, which exist in skeletal muscle, ie subsarcolemmal and intermyofibrillar, are differently affected by high-fat feeding. DESIGN: Weaning rats were fed a low-fat or a high-fat diet for 15 days. MEASUREMENTS: Energy balance and lipid partitioning in the whole animal. State 3 and state 4 oxygen consumption rates in whole skeletal muscle homogenate. State 3 and state 4 oxygen consumption rates, membrane potential and uncoupling effect of palmitate in subsarcolemmal and intermyofibrillar mitochondria from skeletal muscle. RESULTS: Rats fed a high-fat diet showed an increased whole body lipid utilization. Skeletal muscle NAD-linked and lipid oxidative capacity significantly increased at the whole-tissue level, due to an increase in lipid oxidative capacity in subsarcolemmal and intermyofibrillar mitochondria and in NAD-linked activity only in intermyofibrillar ones. In addition, rats fed a high-fat diet showed an increase in the uncoupling effect of palmitate in both the mitochondrial populations. CONCLUSIONS: In young rats fed a high-fat diet, skeletal muscle contributes to enhanced whole body lipid oxidation through an increased mitochondrial capacity to use lipids as metabolic fuels, associated with a decrease in energy couplin

Mutation in a winged-helix DNA-binding motif causes atypical bare lymphocyte syndrome

Bare lymphocyte syndrome (BLS) is an autosomal recessive severe-combined immunodeficiency that can result from mutations in four different transcription factors that regulate the expression of major histocompatibility complex (MHC) class II genes. We have identified here the defective gene that is responsible for the phenotype of the putative fifth BLS complementation group. The mutation was found in the regulatory factor that binds X-box 5 (RFX5) and was mapped to one of the arginines in a DNA-binding surface of this protein. Its wild-type counterpart restored binding of the RFX complex to DNA, transcription of all MHC class II genes and the appearance of these determinants on the surface of BLS cells