Comparisons of different methods for virus-elimination of edible fungi / 病毒学报

Four dsRNA bands were extracted from Pleurotus ostreatus TD300 by the dsRNA isolation technique with sizes of 8.2 kb, 2.5 kb, 2.1 kb, and 1.1 kb, respectively. Four virus-eliminated methods, i. e. hyphal tips cut (HTC), protoplast regeneration (PR), single spore hybridization (SSH), and frozen and lyophilized (FL), were applied to prepare virus-eliminated strains, and one virus-eliminated strain was selected for each virus-elimination method. The virus-eliminated strains were named as HTC8, PR15, FL01, and SSH11, respectively. There were low concentration of 8.2 kb dsRNA remained in HTC8, as well as low concentration of 8.2 kb and 2.5 kb dsRNA remained in FL01. However, no dsRNA remained in PR15 and SSH11. The hyphal growth rate and laccase activity of the virus-eliminated strains increased, especially HTC8 and PR15, whose hyphal growth rate was higher by 22.73% and 18.18%, and laccase activities higher by 145.83% and 134.38% than that of the original strain, respectively. The conclusion is that hyphal tips cut and protoplast regeneration are suitable to prepare virus-eliminated strains of edible fungi.

Should Strengthen Cognizing and Teaching to the Deceleration Phase of Single Cell Organisms Growth Curve in Batch Cultivation / 微生物学通报

The growth curve of single cell organisms in batch cultivation could divide into 6 phases, lag phase, acceleration phase, log phase, deceleration phase, stationary phase, and death phase, based on specific growth rate during cultivation process. There were significantly differences between deceleration phase and the other phases in cell growth, substrate consumption, product formation, and genes express profile. The deceleration phase was highly important to fermentation process. However, cognizing and teaching to the deceleration phase had been considerably weakened since a long period. So it should be strengthened.

The Research Advance of Heterokaryon Incompatibility Mechanism in Fungi / 微生物学通报

Heterokaryon incompatibility is a widespread phenomenon among fungi,controlled by specific loci termed het (for heterokaryon incompatibility).This review focuses on recent developments in our understanding of the molecular mechanisms of nonself recognition and the relationship between the death progresses of heterokaryon incompatibility and associated proteins in fungi.The deep research of heterokaryon incompatibility mechanism will hopefully reveal underlying principles of the evolution of nonself recognition systems and will find some effective method for settling the instability of protoplast fusant of fungi.

Study on the Optimal Fermentation Process for Production Chitinase of Streptomyces sp. A048 / 微生物学通报

Streptomyces sp. A048 was cultured in a complete medium to the last stage of log phase,the hyphae were washed and collected by centrifugation. Then the hyphae were inoculated in liquid medium for chitinase production using two-step fermentation. Activity of chitinase produced by two-step fermentation was 1.1 times higher than that from one-step fermentation,and ferment cycle was for 54 hours,which was 66 hours shorter than that of one-step fermentation. The hyphae and the powder of chitin were co-immobilizated and cultured in liquid medium for 36 hours,activity of chitinase was 1.8 times higher than that from one-step fermentation,and ferment cycle was 54h shorter than that of one-step fermentation. By adding 0.4% cellulose to two-step fermentation,activity of chitinase was 18.52 U/mL that was 4 times higher than that from the control and 10 times higher than that from one-step fermentation. Two step fermentation with chitin and cellulose may be the optimal fermentation process to produce Chitinase from Streptomyces sp. A048.