Carbendazim resistance and calculation effective concentration of carbendazim for Trichoderma harzianum

There is a method for investigating the transformation of resistance gene of carbendazim into Trichoderma harzianum. In order to introduce the resistance to benzimidazole fungicide into bio-control microorganism Trichoderma harzianum was transformed with the resistance gene. In this study, we investigate resistance level and calculate EC 50 (effective concentration of carbendazim that can survive 50% of Trichoderma harzianum in that concentration) and stability of the resistance for the transformant isolate of Trichoderma harzianum. Results show the transformants can growth on the medium containing more than 1 000 μg/ml carbendazim and the resistance is stabled after 10 times transfer on non-selective medium and have EC 50 average about, 1 200 μg/ml.

In Vitro Detection of Herbicide-Tolerant Fungi Isolated from Pesticides Polluted-Soil

Forty-five rhizofungal isolates were isolated, identified and characterized from 11 herbicides polluted-soil. Among the isolates, 10 fungal species proved to be the most potent and promising ones in herbicides tolerance. The herbicides exhibited severe and dramatic effect and modulation on fungal DNA and protein represented in DNA and protein profile. Severely loss in the total soluble cell ions （SCI） and total cell protein percentage （TCPC） concentrations were observed. The loss of SCI by glyphosate, Aspergillus flavus （86,30%） was the most affected one, followed by Penicillium spiculisporus （76,30%）, Penicilliurn verruculosum （64.40%） and Alternaria tenuissima （64%）, respectively. For pendimethalin, Alternaria tenuissima （54.01%） was the most affected fungi. For diclofop-methyl, Penicillium spiculisporus （74.20%） was the most affected fungi. The loss of TCPC by glyphosate, Alternaria tenuissima （64.71%） was the most effected fungi, followed by Penicillium spiculisporus （57.14%）, respectively. For pendimethalin, A. terreus （54.29%） w, as the most affected fungi. For diclofop-methyl, Penicillium spiculisporus （60%） was the most affected fungi, fbllowed by Alternaria tenuissima （58.82%）, Aspergillus tamarii （55.56%）, respectively. The results proved severe reductions and alteration in protein, SCI, TCPC and DNA in fungal strains exposed to these herbicides which might reflex a degree of tolerance occurred during the assimilation of those toxic compounds from the pesticides polluted-soil.

DMSO胁迫提高发光细菌毒性实验敏感度的研究

利用二甲基亚砜(DMSO)胁迫,以发光细菌青海弧菌Q67种为实验菌种,通过与标准物质作用测定相对发光值确定其生物毒性效价,对多种食品中可能存在的污染物进行毒性对比研究。结果表明,DMSO浓度在0.1%~1.0%之间不影响发光细菌正常生理反应,同时可以有效的提高其对毒性物质作用毒性。DMSO能明显提高发光细菌的检测敏感度,有效降低半数致死量EC50。对受试重金属汞、铜、镉和锌,其提高效率为43.28%~58.50%;四环类抗生素中盐酸金霉素、盐酸四环素和土霉素的提高效率在8.2%~11.6%之间;抗菌类农药二氰蒽醌、溴菌腈、甲霜灵和异菌氟腚胺的提高效率为10.49%~38.32%。DMSO的胁迫促进效果适用于多种毒性物质,并且能够在短时间内提高作用效果(30 min以内),为食品领域应用生物毒性检测方面提供了一种新的分析方法。