Proteasomes are multi-subunit proteases involved in several mechanisms and thought to contribute to the regulation of cellular homeostasis. Here, we report for the first time biochemical evidence for the existence of a ubiquitin-proteasome proteolytic pathway in this parasite. Proteasomes from both cercariae and adult worms exhibited a high preference for hydrolysis of the substrate Suc-LLVY-AM...

The vectorial capacity of Biomphalaria pfeifferi from Ndiangue, Senegal, was investigated with an allopatric isolate of Schistosoma mansoni from Nkolbisson, Cameroon. The snail infection rate after exposure to a single miracidium per snail (MD1) was 56. 3 %, and 91.6%, for snails exposed to 5 miracidia per snail (MD5). The minimum pre-patent period was 21 days. The mean total cercarial producti...

Natural infections of Galba truncatula with Haplometra cylindracea were followed from 2001 to 2009 to determine if their characteristics were similar when snails came from water collections frequented by Bufo bufo or by frogs and newts for their egg-laying. Snail samples were collected from both types of sites to count shed cercariae for three days and also free cercariae when snails were disse...

Schistosomiasis is a debilitating disease that affects over 240 million people worldwide and is considered the most important neglected tropical disease following malaria. Free-swimming freshwater cercariae, one of the six morphologically distinct schistosome life stages, infect humans by directly penetrating through the skin. Cercariae identify and seek the host by sensing chemicals released f...

Background: Agrochemicals are widely used in many parts of the world posing direct and indirect threats to organisms. Xenobiotic-related disease susceptibility is a common phenomenon and a proposed cause of amphibian declines and malformations. For example, parasitic infections combined with pesticides generally pose greater risk to both tadpoles and adult frogs than either factor alone. Here, ...

Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of nonspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the...

BACKGROUND Trematodes belonging to the genus Schistosoma cause schistosomiasis. The relationship between schistosomes and their intermediate hosts varies among snails. This study investigated the effects of S. japonicum on its snail host, Oncomelania hupensis, and cercarial release rythmicity of S. japonicum and the effects of light on it. METHODS Seven groups of O. hupensis (n = 40 each) wer...

Fresh water snails, Semisulcospira libertina, including S reiniana and S. japonica, are known as the first intermediate hosts of pathogenic trematodes, e. g. Paragonimus, Metagonimus, etc. These snails are also infected with many other non-pathogenic cercariae, the majority of which have been described up to now incompletely. Therefore, in the case of epidemiological studies, research workers u...

N,N-diethyl-3-methylbenzamide (DEET) has recently been reported to kill cercariae of Schistosoma mansoni in vitro. In addition, it blocked cercarial entry into mouse tail skin. We confirmed these results and compared the efficacy of DEET to a second insect repellent, 1-(3-Cyclohexen-1-yl-carbonyl)-2-methylpiperidine (AI3-37220), in preventing S. mansoni infections in mice. Both AI3-37220 and DE...

Schistosoma mansoni cercariae display specific behavioral responses to abiotic/biotic stimuli enabling them to locate and infect the definitive human host. Here we report the effect of such stimulants on signaling pathways of cercariae in relation to host finding and invasion. Cercariae exposed to various light/temperature regimens displayed modulated protein kinase C (PKC), extracellular signa...