Identification of Phytopathogenic Virus Strains by their Luminescent Properties

A quick test has been developed to identify phytopathogenic virus strains by variations in their photoluminescence parameters. When heated, the virus suspension shows a jumpwise drop or rise in fluorescence intensity caused by conformational changes in the macromolecules of the virion protein capsules. The relative value of the jump in fluorescence intensity and the temperature value at which the jump occurs are essentially strain-specific. The minimum time needed for one test is from 15 to 20 minutes.     

Role of pituitary hormones in regulating renal vitamin D metabolism in man.

Studies in animals and tissue culture have shown the importance of prolactin and growth hormone in regulating renal 1 alpha-hydroxylase activity and plasma concentrations of 1,25-dihydroxycholecalciferol (1,25(OH)2D3). Evidence for a similar role for these hormones in man was sought by using a radioreceptor assay to measure plasma 1,25(OH)2D3 concentrations in 20 normal subjects, 12 patients receiving dialysis, 11 patients with primary hyperparathyroidism, 10 pregnant women, seven women with prolactinoma, and 14 patients with acromegaly. Circulating 1,25(OH)2D3 concentrations were appreciably raised in the patients with primary hyperparathyroidism and the pregnant women (P less than 0.001), slightly but significantly increased in the patients with prolactinoma (P less than 0.05), and greatly raised in those with acromegaly (P less than 0.001). These results suggest that prolactin and growth hormone are important regulators of renal vitamin D metabolism in the physiological conditions of pregnancy, lactation, and growth in man.     

Germination of the chlamydospores of Candida albicans

Using a slide culture technique, it was determined unequivocally that the chlamydospore of Candida albicans does germinate. The germination was by way of a multiple-budding process which was associated mostly with young spores following their transfer to a fresh environment. It is concluded the chlamydospore of C. albicans is a reproductive cell with a transient viability.     

Isolation of Temperature-Sensitive Membrane Mutants of Escherichia coli K-12

Mutants with impaired biosynthesis of unsaturated fatty acids or altered metabolism of the phospholipids were isolated at a rather high frequency from a set of temperature-sensitive lysis mutants. It is suggested that preselection for the lysis phenotype makes it possible to isolate several kinds of mutants affected in the integrity of the cytoplasmic membrane.