Robert W. Krauss

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The chlorophyll a:b ratio was shifted in Chlorella vannielii by varying the illuminance under which the cells were cultured-the ratio increased from 2.9, 3.0, 4.0, and 4.8 to 6.2, respectively, at 100, 300, 900, 2,700 and 6,000 foot candles. The 6,000-foot candle cells retained an optimal growth rate at the chlorophyll a:b ratio of 6.2 which was the upper(More)
Growth is most often measured as increase in mass. In an individual cell this process is interrupted by cell division. Growth studies on nonsynchronized microbial populations usually produce data affected by both of these processes since a nonsynchronized population consists of cells in various developmental stages. The separation of growth from cell(More)
Halimeda is a prominent part of the calcifying algae in the coral-reef lagoon ecosystems in the Caribbean. Experiments were performed on the Cayo Enrique Reef off Puerto Rico and in the laboratories of the University of Maryland to study factors influencing the calcification processes. Halimeda opuntia has a higher percentage of calcium carbonate than does(More)
Multicellular organisms and steady-state microbial populations consist of cells in all possible developmental stages. In such populations some cells are vigorously growing, others are preparing to divide, and stll others are actually in the process of cell division. Environmental conditions necessary for the optimum development of one stage in the life(More)
Glucose cultures of Chlorella vulgaris were grown in white light, in monochromatic light, and in darkness. Difference spectra showed that all wavelengths resulted in increased pigmentation over the dark controls.Cells irradiated with the 600 mmu beam showed a much higher absorption in the blue end of the spectrum with respect to the red end than is normally(More)
Chlorella vulgaris Beyerinck (Emerson's strain), fails to grow in the dark even when sugars are provided. This phenomenon was clearly demonstrated in the alga, C. vulgaris, for which the growth rate in darkness on a glucose medium remained constant for 2 days and then declined to approach zero. Pigment concentrations also declined in darkness. Changes in(More)
We investigated the effect of the bile acid sequestrant, colestipol hydrochloride, on the composition and metabolism of human low density lipoprotein (LDL). Colestipol treatment produced a disproportionate decrease in LDL cholesterol compared to LDL apoB, resulting in a significant decrease in the LDL cholesterol/apoB ratio. Electron microscopy revealed(More)