Effect of the method of agitation on the accumulation of protective antigen in cultures of Bacillus anthracis.
Accumulation of protective antigen was essentially independent of culture volume, provided the organisms were kept in suspension by stirring. Agitation by orbited shaking was unsatisfactory.
STUDIES ON IMMUNITY IN ANTHRAX IX
Wright, George G. (Fort Detrick, Frederick, Md.), Milton Puziss, and W. Brook Neely. Studies on immunity in anthrax. IX. Effect of variation in cultural conditions on elaboration of protective antigen by strains of Bacillus anthracis. J. Bacteriol. 83:515–522. 1962.—Nonproteolytic and nonencapsulated avirulent mutants were isolated from six virulent strains of Bacillus anthracis and tested for elaboration of protective antigen in the chemically defined medium developed previously (599 medium). Initially the strains grew rather slowly in 599 medium; serial transfer in the medium increased the rate of growth but reduced the elaboration of antigen. Two of the strains tended to revert to the encapsulated form during serial passage in 599 medium. Modifications in the medium and cultural conditions were studied in an attempt to obtain improved growth; the most significant alterations were the addition of adenosine and l-alanine, reduction in the concentration of ferrous sulfate, and growth under anaerobic conditions with agitation. Study of amino acid utilization in the medium revealed that the concentrations of certain amino acids could be reduced. These modifications, together with substitution of more productive strains, resulted in an approximately fivefold increase in elaboration of protective antigen, and greatly simplified production of the antigen on a practical scale. Omission of bicarbonate from the medium had no significant influence on utilization of amino acids.
The Determination of Physicochemical Characteristics of Biodiesel and Its Blending Oils
The viscosity,combustion heat,sulfur content,carbon residue,ash,flash point,moisture and cetane value of biodiesel and its blending oils with diesel were determined.The influence of temperature on the viscosity was studied,and the physicochemical characteristics of biodiesel and its blending oils were compared with diesel.The results indicated that biodiesel and its blending oils had some superior performances and good application prospect.