Destruction of toxic fungi with low concentrations of methyl bromide

Aspergillus parasiticus and Penicillium rubrum spores at the level of 10(4) to 10(5) / g were completely killed by prolonged exposure to 30 to 45 mg of methyl bromide per liter.

Enzymatic and 14C-mannitol studies of the Aspergillus mannitol metabolism

Aspergillus species (UC4177) accumulated mannitol from glucose substrate and it also used mannitol as the sole carbon source. Experiment with radioactive mannitol showed that the accumulation of mannitol and the oxidation of mannitol to CO2 proceeded simultaneously. The presence of glucose in the medium did not inhibit mannitol oxidation. Mannitol was oxidized at about 25% of the metabolic rate of glucose. The rate of mannitol oxidation and several of the enzymes directly involved in mannitol metabolism were unaffected by using glucose or mannitol as the sole source of carbon. Nine enzymes of glucose metabolism were tested and none appeared to limit the rate of glucose oxidation. Aspergillus phosphofructokinase was not inhibited by 2.4 mM ATP or 10 mM citrate. Possible enzymatic defects favoring mannitol accumulation were not found.

Sampled fourier transform hologram generated by computer

A technique to determine a real nonnegative function representing the transmittance of a synthesized hologram is described. The technique uses the positions of the samples in the synthesized hologram to record the phase information of a complex wavefront. Synthesized holograms are displayed on a flying spot scanner and recorded on film. The transmittance of the synthesized hologram is quantized into 256 levels because of a hardware limitation of the scanner.

Serine requirement in leukemic and normal blood cells

In a serine-deficient medium, cells from humangt chronic granulocytic leukemia and normal human bone marrow exhibited a marked inhibition of incorporation of-radioactive precursors of DNA, RNA, and protein into an acid insoluble cell fraction. Normal diploid human fibroblasts did not exhibit inhibition without serine. Chronic granulocytic leukemia and normal marrow cells were essentially unable to synthesize C(14)-serine from C(14)-glucose, while human diploid fibroblasts were highly capable of this synthesis.

Chromosomal alterations in marine fish cells in vitro

The modal chromosome number of the GF cell line is 46, consisting of 44 telocentrics and two metacentrics. Primary grunt fin tissue exhibits 2n = 48; all are telocentric chromosomes. The modal cell of the GF cell line does not represent the in vivo genetic constitution conserved by Robertsonian translocation since the modal cells are variously haploid or nullo for the chromosome pair bearing secondary constrictions. Despite the fact that GF cells possess 44 telocentric chromosomes, only limited centric fusion appears to have occurred during 8 years of culture in vitro.

Improved separation of sterols by column chromatography

Some closely related sterols have been separated on columns of neutral alumina-Super-Cel impregnated with silver nitrate. Most notable are the separations of some Delta(8)-sterols from their Delta(7)-isomers, separations which have been difficult, if not impossible, to achieve with other published column chromatographic methods.

Carbon balance of a mannitol fermentation and the biosynthetic pathway

The carbon balance was determined for a fermentation in which mannitol is produced from glucose by an Aspergillus species. The products found were: cells (17% of carbon input), CO(2) (26%), mannitol (35%), glycerol (10%), erythritol (2.5%), glycogen (1%), and unidentified compounds (8%). Thus, 92% of the carbon input was accounted for. Cell-free enzyme studies showed that mannitol was synthesized via the reduction of fructose-6-phosphate and not by the direct reduction of fructose. If the cell yield from glucose was assumed to be 50% and the theoretical conversion efficiency from glucose to polyols was 90%, as calculated from the energy balance, then 34% of the glucose carbon was used for growth and 53% was used for polyol formation.

Thin-layer chromatography of sterols on neutral alumina impregnated with silver nitrate

Thin-layer chromatography for the rapid separation of several sterols on neutral alumina impregnated with silver nitrate is described. The method is particularly effective for sterols that differ in the number and location of olefinic bonds.