| Aflatoxin is a fungi toxin that it not only badly pollutes the environment but alsogreatly does harm to person and brute. It is mainly produced by Aspergillus flavus andAspergillus parasiticus, and mainly contaminates maize, peanut, nut, and their productions.Considering food safety, it has been seeking that a safety, economy and effective methodwas used in inhibitting or decomposing aflatoxin. Some beneficialmicroorganisms, with inhibition of A. flavus gained by screening, and/or theiractive substances are used to destroy or reduce Aflatoxin in farm produce, which isincreasingly developing a significant and effective way access to control of aflatoxin.Based on Aspergillus niger's characteristic in physiology the test protocol was designed asfollows. A. niger, as a original strain, was implanted with N+ ions, and the strain ofinhibitive effects on aflatoxin was screened out from these mutant; the enzyme thatdecomposes the toxion was separated from the fermented broth of the mutant strain, andfinally was used in processing of the farm produces contamined aflatoxin. A.niger, imperfecti fungi, belongs to Hyphmycetes, Hyphmycetes, and Aspergillus,which extentively exists in soil under various climate. Because of the high yield andmultiplicity of A. niger's enzyme, these enzyme preparations not only adopt toindustrialization production, but also are safe, dependable and low-toxicity. The currentstudies focus on the hot aspect that A. niger is screened from the nature to gain a new-typestrain via biotechnology, e.g. ultraviolet radialization, laser irradiation, microwaveradiation, plasmogamy and gene transfer et al. The contents as follows were presented in this paper. N+ ions beam was implantedinto A. niger at dose of 30×2.6×1013, 50×2.6×1013, 70×2.6×1013, or 90×2.6×1013N+/cm2 respectively, under 20 Kev. With the effects of N+ ions beam on A. niger in energyaggradation, momentum transfer, mass aggradation and charge exchange, the N+ ionsimplantation induced the mutation of chromosome in A. niger. In each dose exposuredgroup, the biggest and the smallest colony were selected to enlarge respectively. And thenscreening of the best culture medium was conducted according to the growth state ofmutant strain in different substrate. The results indicated that as follows. Firstly, theactivity of Na+-K+ATPase in the membrane changed along with different the dose ofimplanted N+ ions, which resulted in changes on the utilization and absorption coefficientof the mycelial cell to nutriment in culture medium; the stability, selectivity andpenetrability of membrane and its metabolism states were also affected by N+ ions beamwith different dose. Secondly, the activities of malate dehydrogenase (MDH) and succinate vdehydrogenase (SDH) were varied by N+ ions implantion at different dose of exposure.There were two kinds of MDH, one was in cytoplasm, and another came frommitochondria; the MDH in cytoplasm was correlated with the biosynthesis, e.g. as areducing agent in lipid biosynthesis affecting the membranous fluidity. The SDH activityhad effects on energy creating and rtaio of tricarboxylic acid cycle. Thirdly, the activities ofenzyme and isoenzyme, MDH, PPO, catalase, POD, amylase, esterase, or (SOD), wereaffected after N+ ions beam was implanted, however, new isoenzymes were not induced insame case. Fourthly, the shape and structure of A. niger's spores were changedcompanying with the implantation of N+ ions beam. To sum up, analyzing correlative parameters, a mutation strain 90A with the bestsynthetical parameter signs was screened. In the antagonistic experiment of A. niger and A.flavus, it was found that a mutation strain 90A inhibited A. flavus from growth based onsome mechanisms such as adhering to, coiling around, paralleling, or decomposing hyphaet al. Three tests were designed in our investigation, which was A. flavus probuced toxinswas solely cultivated, A.
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