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H O HALVORSON

Publications and source records attributed to H O HALVORSON.

At least 37 records · Page 2Linked to original sources
PubMed1962

Calcium dipicolinic acid-induced germination of Bacillus cereus spores.

Keynan, A. (University of Wisconsin, Madison) and H. O. Halvorson. Calcium dipicolinic acid-induced germination of Bacillus cereus spores. J. Bacteriol. 83:100-105. 1962.-The germination of spores of Bacillus cereus strain T can be initiated by calcium dipicolinic acid. The kinetics of germination are characterized by a long lag period followed by a rapid loss of refractility. The lag period displays the temperature dependence of a metabolic reaction, whereas the rate of germination is relatively independent of temperature. Germination induced by calcium dipicolinic acid is insensitive to l-alanine analogues, is sensitive to metabolic poisons, and proceeds without a detectable activation stage. It was concluded that calcium dipicolinic acid-induced germination has a metabolic basis and differs, at least in its initial phases, from l-alanine-induced germination.

Alanine↗
PubMed1962

Germination properties of spores with low dipicolinic acid content.

Keynan, A. (University of Wisconsin, Madison), W. G. Murrell, and H. O. Halvorson. Germination properties of spores with low dipicolinic acid content. J. Bacteriol. 83:395-399. 1962.-When the dipicolinic acid content of spores of Bacillus cereus strain T is reduced from 7.5 to 2 or 3%, the spores germinate spontaneously after heat activation and are sluggish in their response to l-alanine and other germination agents. Only germination initiated by calcium dipicolinic acid is unaffected. l-Alanine-induced germination is stimulated by exogenous dipicolinic acid. These results support the hypothesis that endogenous dipicolinic acid regulates the l-alanine-triggered germination.

Alanine↗
PubMed1962

Metabolic control of beta-glucosidase synthesis in yeast.

MacQuillan, Anthony M. (University of Wisconsin, Madison) and Harlyn O. Halvorson. Metabolic control of beta-glucosidase synthesis in yeast. J. Bacteriol. 84:23-30. 1962-The hybrid Saccharomyces fragilis x S. dobzhanskii produced a constitutive beta-glucosidase when grown in succinate synthetic medium. Upon addition of beta-glucosides, thio-beta-glucosides, or low concentrations of glucose, a further induction of enzyme synthesis was observed. Studies with other sugars revealed some specificity in response to hexose induction. Phenyl-thio-beta-d-glucoside did not affect constitutive synthesis nor induction by glucosides, thio-glucosides, or glucose. Repression of beta-glucosidase synthesis is brought about by high concentrations of glucose and other carbon compounds. Preinduction does not confer resistance to catabolic repression of enzyme synthesis; this leads to the conclusion that two sites of control for beta-glucosidase synthesis are present in yeast. Multiplicity of control is further suggested from: (i) the properties of the inducing system; (ii) semiconstitutive nature of enzyme synthesis; (iii) the repression of constitutive synthesis by glucose; (iv) the elevated derepressed rates of enzyme synthesis after glucose inhibition; and (v) the selection of a family of low constitutive mutants with variable inducibility.

Cellulases↗
PubMed1962

Physiological changes occurring in yeast undergoing glucose repression.

MacQuillan, Anthony M. (The University of Wisconsin, Madison) and Harlyn O. Halvorson. Physiological changes occuring in yeast undergoing glucose repression. J. Bacteriol. 84:31-36. 1962.-Growth of the hybrid yeast Saccharomyces fragilis x S. dobzhanskii on glucose or lactate resulted in (i) the possible impairment of a permeation system for succinic acid, (ii) the repression of succinic and isocitric dehydrogenases and beta-glucosidase, and (iii) the induction of isocitratase. The latter two changes were not observed in S. lactis Y14, in which beta-glucosidase synthesis is resistant to glucose repression.

Glucose↗
PubMed1961

L-Alanine dehydrogenase: a mechanism controlling the specificity of amino acid-induced germination of Bacillus cereus spores.

O'Connor, R. J. (University of Wisconsin, Madison), and Harlyn O. Halvorson. L-Alanine dehydrogenase: A mechanism controlling the specificity of amino acid-induced germination of Bacillus cereus spores. J. Bacteriol. 82:706-713. 1961.-A study has been undertaken of the properties and specificity of germination of spores of Bacillus cereus strain T. In the absence of additional carbon sources, only l-alanine, l-alpha-NH(2)-n-butyric acid, and l-cysteine were effective germinating agents. The physical properties of germination, induced by l-alanine and l-alpha-NH(2)-n-butyric acid following extended heat shock, were in close agreement with those of l-alanine dehydrogenase. The specificity of the germination system, as well as amino acid deamination in vivo, support the view that l-alanine dehydrogenase activity is essential for germination and that the enzyme serves as the initial binding site for l-alanine in heat-shocked spores.

Alanine↗