Showing papers by "Andrew P. Waters published in 1990"
TL;DR: The complete sequence of PK66 was reported which allowed the demonstration that highly conserved analogues exist throughout Plasmodium including a recently reported gene from P. falciparum, which are highly promising vaccination candidates.
140 citations
TL;DR: The identification of a 66-kDa Plasmodium knowlesi late-stage schizont protein by monoclonal antibodies that inhibit in vitro multiplication of P. knowlesi is reported, suggesting that PK66 has a role in the invasion of erythrocytes.
78 citations
TL;DR: Andy Waters and Tom McCutchan describe how simple rRNA methodologies for Plasmodium can detect and identify parasites as well as follow different stages in their development.
71 citations
TL;DR: Type of genetic change that are related to phenotypic changes in the parasite are discussed and mechanisms for generating diversity in combination with the large number of organisms that accumulate during infection as a reservoir for selection are discussed.
Abstract: The genetic diversity among malaria parasites is considerable, and much scientific investigation has focused on the ramifications of this diversity. Here we have discussed types of genetic change that are related to phenotypic changes in the parasite. To date, these changes have not been observed to result from precise mechanisms like the antigenic diversity seen in trypanosomes. Rather, the parasite seems to depend upon less precise mechanisms for generating diversity in combination with the large number of organisms that accumulate during infection as a reservoir for selection.
42 citations
TL;DR: Two structurally distinct ribosomal RNAs occur in different developmental stages of malaria parasites and the transition from one type to the other is found shortly after sporozoites invade hepatocytes, the first stage of parasite development in the mammalian host.
32 citations
TL;DR: The observations suggest that 66 kD‐related antigens may play a role in the orientation of the apical prominence of merozoites towards the red cell, and/or in the junction formation that occurs subsequent to orientation.
Abstract: Summary We have previously reported that Fab fragments of a monoclonal antibody to the 66 kD-related antigens of Plasmodium knowlesi inhibit merozoite invasion of erythrocytes, strongly suggesting a role for these antigens as merozoite receptors for red cells. In this paper we have examined the distribution of these antigens on the surface of free merozoites. Rapid immunofluorescence microscopy on free, unfixed cells demonstrated a preferential association of antigen with a polar region of merozoites. This was confirmed, and localized essentially to the apical region, by immunoelectron microscopy under a variety of fixation regimes. Metabolic inhibitors did not affect the distribution, suggesting that apical localization is not due to capping induced by cross-linking antibodies. These observations suggest that 66 kD-related antigens may play a role in the orientation of the apical prominence of merozoites towards the red cell, and/or in the junction formation that occurs subsequent to orientation.
28 citations
TL;DR: The existence and importance of a small subset of mutations in Plasmodium falciparum genes that continually reoccur in separated populations are documents and indicates that there is a significant natural mechanism relating to the circumsporozoite protein that affects the success of malaria sporozoites.
15 citations