• The Korean Journal of Mycology
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• v.13 no.4
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• pp.221-224
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• 1985

The life cycle of 17 species of Trichoderma was elucidated to seize the proper stage for observing the nuclear behavior and chromosome count. The most convenient stage for the purpose in their life cycle was the stage just before producing the asexual spore. Of the 17 species in the genus Trichoderma the haploid chromosome numbers were counted 5,6,7 and 10. Six chromosomes were most frequently observed. It is believed that the basic chromosome number is placed between 4 and 10, and that the number might be 6, referring to the related papers. It appears necessary to reclassify the single genus of Trichoderma into at least two or three genera.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.251-262
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• 1986

High-molecular-weight ${\beta}-glucosidase$ (EC 3.2.1.21) was purified from the culture filtrate of Trichoderma koningii through a four-step procedure including chromatography on Bio-Gel P-150, DEAE-Sephadex A-50 and SP-Sephadex C-50; and chromatofocusing on Polybuffer exchanger PBE 94. The molecular weight of the enzyme was determined to be about 101,000 by SDS-polyacrylamide gel electrophoreses, and the isoelectric point was estimated to be 4.96 by analytical isoelectric focusing. The temperature optimum for activity was about $55^{\circ}C$, and the pH optimumwas 3.5. The enzyme was considerably thermostable, for no loss of activity was observed when the enzyme was preincubated at $60^{\circ}C$ for 5h. Km values for cellobiose, gentiobiose, sophorose, salicin and $p-nitrophenyl-{\betha}-D-glucoside$ were 99.2, 14.7, 7.09, 3.15 and 0.70 mM, respectively, which indicates that the enzyme has much higher affinity towards $p-nitrophenyl-{\betha}-D-glucoside$ than towards the other substrates, especially cellobiose. Substrate inhibition by $p-nitrophenyl-{\betha}-D-glucoside$ and salicin was observed at the conecntrations exceeding 5mM. Gluconolactone was a powerful inhibitor against the action of the enzyme on $p-nitrophenyl-{\betha}-D-glucoside\;(K_i\;37.9\;{\mu}M)$, wherease glucose was much less effective ($K_i$ 1.95 mM). Inhibition was of the competitive type in each case. Transglucosylation activity was detected shen the readtion products formed from $p-nitrophenyl-{\betha}-D-glucoside$ by the enzyme were analysed using high-performance liquid chromatography.