scholarly journals STUDIES ON CONDITIONS AFFECTING THE SURVIVAL IN VITRO OF A MALARIAL PARASITE (PLASMODIUM LOPHURAE)

1941 ◽  
Vol 74 (5) ◽  
pp. 441-462 ◽  
Author(s):  
William Trager
Keyword(s):  
Liver Extract ◽  
Cell Extract ◽  
Malarial Parasite ◽  
Red Cell ◽  
High Potassium ◽  
Plasmodium Lophurae ◽  
Parasite Plasmodium ◽  
Chick Embryo Extract ◽  
Very High

The survival of Plasmodium lophurae in vitro, at temperatures of 39.5–42°C., is favored by a balanced salt solution having a high potassium content, by aeration but not by a very high oxygen tension, by an optimal density of parasites per cubic millimeter, by frequent renewal of the suspending medium, by concentrated red cell extract, by optimal concentrations of plasma or serum, of chick embryo extract, of glucose or glycogen, and of glutathione, and probably by yeast extract and a very low concentration of liver extract. In the best preparations, as judged by infectivity, more than 40 per cent of the parasites were alive on the 3rd day, more than 20 per cent on the 4th day, perhaps 1 per cent on the 5th day, and about 0.05 per cent on the 6th day. Evidence was obtained that the parasites had multiplied during the 1st day of incubation.

scholarly journals FURTHER STUDIES ON THE SURVIVAL AND DEVELOPMENT IN VITRO OF A MALARIAL PARASITE

1943 ◽  
Vol 77 (5) ◽  
pp. 411-420 ◽  
Author(s):  
William Trager
Keyword(s):  
Salt Solution ◽  
Cell Extract ◽  
Malarial Parasite ◽  
Red Cell ◽  
Calcium Pantothenate ◽  
Plasmodium Lophurae ◽  
Survival And Development ◽  
Gentle Agitation ◽  
Development In Vitro

The survival of Plasmodium lophurae in vitro is favored by the presence of calcium pantothenate (0.02 mg. per ml). Survival of about 2 weeks in vitro at 40–41°C. has been obtained under the following conditions: a medium consisting of duck red cell extract in balanced salt solution with glutathione and glucose or glycogen, serum, embryo extract, and calcium pantothenate; daily replacement of about half of the medium with fresh medium; addition of fresh uninfected erythrocytes every 2nd day; gentle agitation of the preparation on a rocking machine. In some of these preparations significant increases in male gametocytes and, more rarely, in total numbers of parasites occurred during the first few days.

scholarly journals STUDIES ON THE EXTRACELLULAR CULTIVATION OF AN INTRACELLULAR PARASITE (AVIAN MALARIA)

1950 ◽  
Vol 92 (4) ◽  
pp. 349-366 ◽  
Author(s):  
William Trager
Keyword(s):  
Avian Malaria ◽  
Culture Media ◽  
Cell Extract ◽  
Red Cells ◽  
Red Cell ◽  
Sodium Pyruvate ◽  
Plasmodium Lophurae ◽  
Adenylic Acid ◽  
Survival And Development

The erythrocytic stages of Plasmodium lophurae were freed from their host red cells by specific hemolysis directly into a favorable medium containing an extract of duck erythrocytes. Extracellular survival and development of the parasite in vitro occurred in culture media consisting essentially of a very concentrated extract of duck red cells prepared in a special nutrient solution. Omission or dilution of the red cell extract resulted in rapid degeneration of the parasites. Their survival and development were favored by the presence in the erythrocyte extract of gelatin, yeast adenylic acid, and cozymase, and especially by the further addition of adenosinetriphosphate and sodium pyruvate. Under the best conditions yet tested, all the free parasites continued their development extracellularly during the first two days of cultivation. Merozoites formed by the extracellular segmentation of the free parasites originally present developed further into trophozoites. On the third day a majority of the free parasites were still of normal appearance, but by the fourth day more were degenerate, and very few normal parasites remained on the fifth day.

scholarly journals Localization of ferrochelatase in Plasmodium falciparum

2004 ◽  
Vol 384 (2) ◽  
pp. 429-436 ◽  
Author(s):  
Sundaramurthy VARADHARAJAN ◽  
B. K. Chandrashekar SAGAR ◽  
Pundi N. RANGARAJAN ◽  
Govindarajan PADMANABAN
Keyword(s):  
Plasmodium Falciparum ◽  
De Novo ◽  
Enzymic Activity ◽  
Malarial Parasite ◽  
Parasite Genome ◽  
Marker Proteins ◽  
Parasite Plasmodium ◽  
Theoretical Predictions ◽  
Parasite Plasmodium Falciparum

Our previous studies have demonstrated de novo haem biosynthesis in the malarial parasite (Plasmodium falciparum and P. berghei). It has also been shown that the first enzyme of the pathway is the parasite genome-coded ALA (δ-aminolaevulinate) synthase localized in the parasite mitochondrion, whereas the second enzyme, ALAD (ALA dehydratase), is accounted for by two species: one species imported from the host red blood cell into the parasite cytosol and another parasite genome-coded species in the apicoplast. In the present study, specific antibodies have been raised to PfFC (parasite genome-coded ferrochelatase), the terminal enzyme of the haem-biosynthetic pathway, using recombinant truncated protein. With the use of these antibodies as well as those against the hFC (host red cell ferrochelatase) and other marker proteins, immunofluorescence studies were performed. The results reveal that P. falciparum in culture manifests a broad distribution of hFC and a localized distribution of PfFC in the parasite. However, PfFC is not localized to the parasite mitochondrion. Immunoelectron-microscopy studies reveal that PfFC is indeed localized to the apicoplast, whereas hFC is distributed in the parasite cytoplasm. These results on the localization of PfFC are unexpected and are at variance with theoretical predictions based on leader sequence analysis. Biochemical studies using the parasite cytosolic and organellar fractions reveal that the cytosol containing hFC accounts for 80% of FC enzymic activity, whereas the organellar fraction containing PfFC accounts for the remaining 20%. Interestingly, both the isolated cytosolic and organellar fractions are capable of independent haem synthesis in vitro from [4-14C]ALA, with the cytosol being three times more efficient compared with the organellar fraction. With [2-14C]glycine, most of the haem is synthesized in the organellar fraction. Thus haem is synthesized in two independent compartments: in the cytosol, using the imported host enzymes, and in the organellar fractions, using the parasite genome-coded enzymes.

Developmental modulation of protein synthetic patterns by the human malarial parasite Plasmodium falciparum

1983 ◽  
Vol 61 (12) ◽  
pp. 1304-1314 ◽  
Author(s):  
David R. Allred ◽  
Irwin W. Sherman
Keyword(s):  
Amino Acids ◽  
Plasmodium Falciparum ◽  
Acetylcholinesterase Activity ◽  
Amino Acid Mixture ◽  
Malarial Parasite ◽  
Acid Mixture ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Developmental Modulation

Under conditions of in vitro culture, Plasmodium falciparum incorporated amino acids into particulate (membrane) and soluble proteins in a pattern which changed sequentially and which was dependent upon the stage of parasite maturation. Synchronized cultures pulse labeled with a mixture of 15 14C-labeled amino acids or [14C]histidine alone displayed stage-related patterns of polypeptide biosynthesis. Certain plasmodial proteins were associated with both particulate (membrane) and soluble fractions, whereas others appeared to be specific to a given fraction. Proteolysis of intact infected cells with pronase under conditions which removed 97 ± 2.2% of the endogenous red cell acetylcholinesterase activity did not cause the apparent removal of any radiolabeled proteins; this suggests the absence of externally exposed, parasite-synthesized proteins in the infected red cell membrane. Such a result was consistent whether the radiolabel was [14C]histidine or the 14C-labeled amino acid mixture. These results indicate that specific modulation of parasite biosynthetic patterns occurs during the asexual reproductive cycle and is probably one mechanism whereby parasite differentiation occurs. Despite the formation of surface excrescences on infected red cells containing mature parasites, results of surface digestion experiments failed to demonstrate the presence of surface-exposed plasmodial proteins.

scholarly journals THE DEVELOPMENT OF LEISHMANIA DONOVANI IN VITRO AT 37°C

1953 ◽  
Vol 97 (2) ◽  
pp. 177-188 ◽  
Author(s):  
William Trager
Keyword(s):  
Human Serum ◽  
Human Erythrocyte ◽  
Small Proportion ◽  
Culture Medium ◽  
Leishmania Donovani ◽  
Cell Extract ◽  
Rabbit Serum ◽  
Red Cell

Suspensions of leishmanias from the spleen of hamsters infected with Leishmania donovani were placed in culture flasks and incubated at 37°C. In a medium of human erythrocyte extract and human serum there appeared within a day or two aflagellate forms resembling leishmanias but larger, as well as other aflagellate forms more nearly resembling rounded leptomonads. These intermediate forms multiplied during the first 4 days of culture. They then slowly died off, despite frequent renewal of the culture medium. Sometimes a small proportion of motile, typical leptomonads also appeared in such cultures. Leptomonads from cultures maintained at 28°C., when placed in the human red cell extract-human serum medium and incubated at 37°C., survived at least 4 days. For both types of effect, human serum could be replaced by normal hamster serum but not by rabbit serum. Nicotinamide, added to the human red cell extract-human serum medium at a concentration of 400 mg. per 100 ml., completely prevented the development of intermediate forms from leishmanias and brought about the rapid death of leptomonads at 37°C.

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