Plasmodium knowlesi

Deoxoartemisinin and carboxypropyldeoxoartimisinin have also been shown to have anti-tumour activity and, NMR studies on solution conformations have been reported <00BBR359>. One of the problems with artemisinin use is its poor water solubility characteristics. An attempt to rectify this, and to overcome stability problems associated with sodium artesunate in solution, has involved the introduction of amino group functionality as in 127 (eg. R = 0(CH2)3NR r2 where NR r2 = morpholine). The maleate salt of this compound has reasonable water solubility and aqueous solutions are stable at room temperature for an extended time. However activity against Plasmodium knowlesi in rhesus monkeys after oral administration was poorer compared with artesunic acid <00JMC1635>. 

B7. Brown, K. N., and Brown, I. N., Immunity to malaria. Antigenic variation in chronic infections of Plasmodium knowlesi. Nature (London) 208, 1286-1288 (1965). 

Four principal species from the genus Plasmodium cause natural human infection Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum. P. falciparum is the most lethal as it causes approximately 90% of malaria-related deaths (1). An additional species, Plasmodium knowlesi, which generally infects macaques, has also been shown increasingly to infect humans as well (4). As more sophisticated diagnostic tests are now able to easily distinguish one species of Plasmodium from another, it is thought that infection with P. knowlesi has heretofore been underreported because this species morphologically resembles other Plasmodium species in blood smears (5). 

Sermwittayawong N, Singh B, Nishibuchi M et al (2012) Human Plasmodium knowlesi infection in Ranong province, southwestern border of Thailand. Malar J 11(1) 36... 

Lucchi NW, Poorak M, Oberstaller J et al (2012) A new single-step PCR assay for the detection of the zoonotic malaria parasite Plasmodium knowlesi. PLoS One 7(2) e31848... 

Ribosomes of Plasmodium knowlesi were isolated and characterized recently by Sherman et al. 21 These ribosomes sedimented in the 80S range and could be dissociated into 60S and 40S subparticles. The ribosomal RNA had a low % G+C of 37% and had sizes of 24.2S and 16.6S.22 The ribosomes demonstrated high activity in poly(IJ)-directed synthesis of polyphenylalanine and were strongly inhibited by 10 4m of nucleocidin, chlortetracycline, ethidium, puromycin, cycloheximide or berenil.23 Similar studies have been also carried out on Plasmodium lophurae, and similar profile of drug sensitivities were demonstrated.24 Most of the well-known antimalarial drugs tested showed no significant inhibitory activity in this in vitro assay. 

Blood group antigen-bearing proteins also serve as receptors for infection agents (Table 10-7). A notable example is the presence of receptors in the Duffy blood group antigens to Plasmodium vivax and Plasmodium knowlesi. Individuals who do not express Duffy antigens are resistant to infection by these malarial parasites. 

It was the search for the mode of action of atabrine (and to a lesser degree quinine) that stimulated the earliest biochemical studies on malaria parasites. The first such study was conducted at the London School of Hygiene and Tropical Medicine (LSHTM, London, United Kingdom) by Christophers and Fulton (1938) using Plasmodium knowlesi, discovered in 1932 in a Malayan kra monkey that had been sent to the... 

Adams, J. H., Hudson, D. E., Torii, M., Ward, G. E., Wellems, T. E., Aikawa, M., and Miller, L. H. (1990). The Duffy receptor family of Plasmodium knowlesi is located within the micronemes of invasive malaria merozoites. Cell 63,141-153. 

Aikawa, M., Cook, R. T., Sakoda, J. J., and Sprinz, H. (1969). Fine structure of the erythrocytic stages of Plasmodium knowlesi. A comparison between intracellular and free forms. Z. Zellforsch. Mikrosk. Anat. 100, 271-284. 

Barnwell, J. W., Howard, R. J., and Miller, L. H. (1982). Altered expression of Plasmodium knowlesi variant antigen on the erythrocyte membrane in splenectomized rhesus monkeys.. Immunol. 128, 224-226. 

Beaumelle, B. D., and Vial, H. J. (1988). Acyl-CoA synthetase activity in Plasmodium knowlesi-infected erythrocytes displays peculiar substrate specificities. Biochim. Biophys. Acta 958, 1-9. 

Chitnis, C. E., and Miller, L. H. (1994). Identification of the erythrocyte binding domains of Plasmodium vivax and Plasmodium knowlesi proteins involved in erythrocyte invasion. J. Exp. Med. 180, 497-506. 

Coggeshall, L. (1938a). the cure of Plasmodium knowlesi malaria in rhesus monkeys with sulfanilamide and their susceptibility to reinfection. Am. J. Trap. Med. Hyg. 18, 715-721. 

Cook, R. T., Rock, R. C., Aikawa, M., and Fournier, M. J. J. (1971). Ribosomes of the malarial parasite, Plasmodium knowlesi. I. Isolation, activity and sedimentation velocity. Comp. Biochem. Physiol. 39B, 897-911. 

Deegan, T., and Maegraith, B. G. (1956a). Studies on the nature of malarial pigment (haemo-zion). I. The pigment of the simian species, Plasmodium knowlesi and P. Cynomolgi. Ann. Trap. Med. Parasitol. 50,194-211. 

Dennis, E. D., Mitchell, G. H., Butcher, G. A., and Cohen, S. (1975). In vitro isolation of Plasmodium knowlesi merozoites using polycarbonate sieves. Parasitology 71,475481. 

Eggitt, M. J., Tappenden, L., and Brown, K. N. (1979). Synthesis of Plasmodium knowlesi polypeptides in a cell-free system. Bull. World Health Organ. 57(Suppl 1), 109-113. 

Inhibition of dendritic cell maturation by malaria is dose dependent and does not require Plasmodium falciparum- erythrocyte membrane protein 1. Infect. Immun. 75,3621-3632. Ellis, J., Ozaki, L. S., Gwadz, R. W., Cochrane, A. H., Nussenzweig, V., Nussenzweig, R. S., and Godson, G. N. (1983). Cloning and expression in E. coli of the malarial sporozoite surface antigen gene from Plasmodium knowlesi. Nature 302,536-538. 

Fulton, J. D. (1939). Experiments on the utilization of sugars by malarial parasites (Plasmodium knowlesi). Ann. Trap. Med. Parasitol. 32, 217-227. 

Gupta, C. M., and Mishra, G. C. (1981). Transbilayer phospholipid asymmetry in Plasmodium knowlesi-infected host cell membrane. Science 212,1047-1049. 

Howard, R. J., Barnwell, J. W., and Kao, V. (1983). Antigenic variation of Plasmodium knowlesi malaria Identification of the variant antigen on infected erythrocytes. Proc. Natl. Acad. Sci. USA 80,4129-4133. 

Korir, C. C., and Galinski, M. R. (2006). Proteomic studies of Plasmodium knowlesi SICA variant antigens demonstrate their relationship with P. falciparum EMP1. Infect. Genet. Evol. 6,75-79. 

Mason, S. J., Miller, L. H., Shiroishi, T., Dvorak, J. A., and McGinniss, M. H. (1977). The Duffy blood group determinants Their role in the susceptibility of human and animal erythrocytes to Plasmodium knowlesi malaria. Br. ]. Haematol. 36,327-335. 

McCormick, G. J. (1970). Amino acid transport and incorporation in red blood cells of normal and Plasmodium knowlesi-infected rhesus monkeys. Exp. Parasitol. 27,143-149. 

Polet, H., and Conrad, M. E. (1968). Malaria extracellular amino acid requirements for in vitro growth of erythrocytic forms of Plasmodium knowlesi. Proc. Soc. Exp. Biol. Med. 127, 251-253. 

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