The fate of the circumsporozoite antigens during the exoerythrocytic stage of Plasmodium berghei.

There has been considerable interest in the circumsporozoite proteins due to their potential use in anti-malarial vaccines. Previous authors have shown that these proteins persist from the invading sporozoite throughout the growing exoerythrocytic or liver stage. We show that the different distributions of these proteins seen during the development of the exoerythrocytic parasite of Plasmodium berghei closely follow morphological changes, which can be recognized under the light microscope.

Immunoelectron microscopic localization of circumsporozoite antigen in the differentiating exoerythrocytic trophozoite of Plasmodium berghei.

The distribution of the circumsporozoite (CS) antigens in the 24 hour exoerythrocytic trophozoite of P. berghei was studied using Lowicryl immunogold electron microscopy. These antigens were present on the plasmalemma of the parasite, in disrupted areas of the host cell cytoplasm adjacent to the trophozoite and around inclusions of the host cell cytoplasm.

The in vitro cultivation of P. falciparum ookinetes, and their enrichment on Nycodenz density gradients.

Employing a simple method of growing ookinetes of Plasmodium falciparum in culture, 40% of mature gametocytes convert to macrogametes, 4% reach the retort-form ookinete stage and 0.45% become mature ookinetes. A single-step gradient centrifugation method on 12.

Transplantable colonic adenocarcinomas in rats.

The induction of colonic adenocarcinoma using two different regimens of dimethylhydrazine (DMH) in Fischer F344 rats is described. Rats receiving 20 mg/kg of DMH per week for 20 weeks developed primary tumors with metastases, whereas rats receiving the same weekly dose for 15 weeks developed primary tumors only. The most common route of metastases was transcelomic which often was associated with ascites.

Recognition, calcium and the control of desmosome formation.

Since desmosome formation requires the participation of two adjacent cells, a crucial initiating event must be recognition between desmosomal adhesion molecules. Studies of mutual desmosome formation between different cell types suggest that the recognition mechanisms are highly conserved between different tissues and different species of animals. A further requirement for desmosome formation is an adequate extracellular concentration of Ca2+ (greater than 0.

The complete development in vitro of the vertebrate phase of the mammalian malarial parasite Plasmodium berghei.

All three 'vertebrate' stages of the rodent malarial parasite Plasmodium berghei berghei were grown in vitro in the absence of the vertebrate host. The parasite was introduced into culture from infected mosquitoes and 2 in vitro culture methods were used sequentially to complete the 'vertebrate' phases of development in hepatoma and erythrocyte host cells. The resultant blood infection produced mature schizonts and male and female gametocytes.

An investigation of the molecular components of desmosomes in epithelial cells of five vertebrates.

We have shown previously, by fluorescent antibody staining, that desmosomal antigens are widely distributed in the tissues of vertebrate animals. Furthermore, we have demonstrated mutual desmosome formation between cells derived from man, cow, dog, chicken and frog. In this paper we have studied the components of desmosomes in a tissue or a cell line from each of these animals by immunoblotting with antibodies raised against the desmosomal components isolated from bovine nasal epithelium.