During the course of Candida albicans antigen production, a variant of this organism was encountered which did not produce hyphae at 37°C. Presented here are some of the characteristics of this variant. It produces hyphae at 25°C on cornmeal agar and synthetic medium plus N-acetylglucosamine and Tween 80. At 37°C, it does not produce hyphae on these media, although C. albicans normally does produce hyphae under these circumstances. In liquid synthetic medium, this variant does not produce hyphae at 37°C. The variant strain was analyzed for DNA, RNA, protein content, and particle size. After 50 to 70 h in balanced exponential-phase growth, particle size distribution was narrow, and there were no differences in the DNA, RNA, or protein content per particle in the two strains. When balanced exponential-phase cultures were brought into stationary phase, both strains contained the same amount of DNA per cell.
The relationship between culture density or phase of growth at 24.5 degrees C and the ability of Candida albicans to form germ tubes when shifted to 37 degrees C was investigated. Evidence is presented demonstrating germ tube production from liquid synthetic medium cultures at all phases of growth. Previous studies reported that only cells from stationary phase cultures were competent to form germ tubes. Comparisons between exponential and stationary phase cultures indicate more rapid and more synchronous germ tube production from cells growing in the exponential phase.
Whether vitamin B1 is deficient or not in normal diets in this countryis open to doubt. It is probable that at times when added amounts of B1 are required, as for instance in childhood, adolescence and during pregnancy and lactation, many persons would benefit from additional B1 and some ill health might be preventable by addition of this vitamin to the diet.It has been calculated by Cowgill that B, requirements are proportional to metabolism. The amounts required daily by an adult weighing ten stone have been variously stated. They are thought to be in the region of four hundred and fifty to one thousand five hundred international units rather than two hundred as was previously suggested. The pregnant and lactating woman seem to require something in the region of one thousand international units daily for optimal well-being. The amount required by an infant has not been ascertained, but a child appears to require relatively more than an adult for each pound of body weight; four hundred interna--tional units has been suggested for a child of four and six hundred and eighty for a child of eleven years. Increase of weight would seem to need increase of vitamin B1. A diet of high caloric value requires this vitamin for its utilization. Vogt-Miillerl states that the more carbohydrates a diet contains the greater the requirements of B1 and this agrees with experimental work on animals.
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