[Show abstract][Hide abstract] ABSTRACT: Tobacco mosaic virus reached higher concentrations when inoculated tobacco leaves were placed in a solution containing 10 g.P. sucrose and 0.2 g.P. calcium phosphate than when in water. Detached leaves in water usually produced momvirus than leaves left on the plants. Other sugars and phosphates also increased virus production. Sugar and calcium phosphate sometimes separately increased the concentration of the virus, but the response was usually greatest to both together. The increase varied with the nutritional state of the plants from which the leaves me and some other environmental conditions. Virus concentration, and the effect of sucrose and calcium phosphate in increasing it, was greater when leaves were in the light than in the dark. Conditions which increased virus concentration also increased the total carbohydrates of the leaves. The effect of various substances on the multiplication of tobacco mosaic virus has been studied in detached tobacco leaves or in disks cut from the leaves. Most of such work has been done to find substances that inhibit multiplication, and there have been few experiments to find conditions under which the virus multiplies most extensively, although work with whole plants has demon- strated that host nutrition and environment both affect virus production. The experiments described below show that virus production is greater in detached leaves placed in solutions containing sugar and phosphate than in water, and that the extent to which sugar and phosphate affect virus multiplication vanes with the physiological conditions of the leaves and depends on whether they are kept in the light or dark.
Journal of general microbiology 01/1954; 9(3):467-74.
[Show abstract][Hide abstract] ABSTRACT: The extracellular development of Plasmodium lophurae in vitro was favored by the addition, to the erythrocyte-extract medium, of a coenzyme A (CoA) preparation of about 75% purity. The effect of CoA was the same regardless of the concentration of free pantothenate in the medium, indicating that the parasites require the complete coenzyme rather than its pantothenic acid moiety. Erythrocyte extracts were found to contain enzymes which hydrolyzed added CoA at a rate such that 8 units per ml. of coenzyme was only slightly destroyed after 3 hours’incubation but almost completely destroyed after 18 hours’incubation at 40°C. The CoA content of erythrocytes from chickens or ducks heavily infected with P. lophurae was about twice as high as that of erythrocytes from uninfected birds. The increased CoA was associated with the parasites, an observation suggesting that malaria parasites can accumulate this essential growth factor which they cannot synthesize. The CoA concentration in the livers of infected chickens was approximately 40% lower than that in the livers of control chickens. The livers of ducks on the 6th day of infection had a slightly lower CoA concentration than those of uninfected ducks. This depletion in CoA, together with the depletion in biotin previously demonstrated in P. lophurae infection, may play a role in the pathology of this infection.
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