Showing papers in "Acta Microbiologica Sinica in 1963"

Studies on several factors affecting the hemagglutinin titer of measles virus

Abstract: A study on several factors affecting the hemagglutinin titer of measles virus was made Without concentrating the infectious tissue culture fluid, the hemagglutinating titre of 1:32--1:64 has been obtained The following factors were found to be important in obtaining high titre hemagglutinin: 1) Type of cell culture used--continuous cell line was better than its corresponding primary cell culture and human renal cell culture better than human ammion cell culture; 2) With the same type of cells, cultures showing over- rapid development of C P E gave low titre of hemagglutinin, although the infectivity titre was found to be approximately the same as those giving high titre of hemagglutinin with late development of C P E culture Change of maintenance medium after 5--6 days of infection in primary cell culture or aftec 2--3 days in continuous cell lines not only maintained the cell in good condition but also stimulated the rapid development of CPE Thus leading to the production of high titre hemagglutinin; 3) Cell cultures in- cubated at 33℃ gave a better production of hemagglutinin than those incubated at 37℃; 4) Treatment of infected cell culture with ultrasonic wave increased the yield of hemag- glutinin to 4 folds By decreasing the concentraction of red blood cell from 1% to 05%, the hemagglutinin titre could be raised to 2 folds

Studies on the production of glycerol and arabitol by osmophilic yeasts iv.carbohydrate metabolism in osmophilic yeasts

Abstract: 1. Activity of enzymes of EMP and pentose phosphate cycle was determined in cell-free extracts of two strains of osmophilic yeasts. i.e., Hansenula arabitolgenes Fang 275 and Zygosaccharomyces chevalieri Guill. 2.309. Except phosphofructkinase, which was not detected in 2.309, all other key enzymes were present in the extracts of both strains. 2. A NADP-linked polyol dehydrogenase, which catalyzed the reduction of di- hydroxyacetone to glycerol (in both 275 and 2.309) and D-Ribulose to D-arabitol (in 275 only) was found in both strains. 3. Respiration experiments using glucose-C~(14) showed that pentose phosphate cycle was more dominant in strain 275. This is in accordance with the fact that strain 275 produced more 5-carbon compound-arabitol.