目的:鉴定一株降解黄曲霉毒素B_1(aflatoxin B_1,AFB1)的霉菌HSK8,通过优化其发酵条件提高AFB_1降解率,并初步探索其降解机制。方法:通过形态学和内部转录间隔区(internal transcribed spacer,ITS)、18S r RNA和26S r RNA序列分析对该...目的:鉴定一株降解黄曲霉毒素B_1(aflatoxin B_1,AFB1)的霉菌HSK8,通过优化其发酵条件提高AFB_1降解率,并初步探索其降解机制。方法:通过形态学和内部转录间隔区(internal transcribed spacer,ITS)、18S r RNA和26S r RNA序列分析对该菌株进行鉴定,并通过单因素试验对发酵条件进行优化,采用薄层层析对AFB_1降解产物进行研究。结果:经鉴定该株霉菌为夏孢生枝孢(Cladosporium uredinicola)。其发酵条件经优化确定为:发酵温度28℃、装液量75 m L/250 m L、接种量15%、发酵时间36 h、初始p H 8.0。薄层层析观察到一个不同于AFB_1的荧光斑点。结论:发酵条件优化后,AFB_1降解率从40.68%提升到68.96%,提高了69.52%;AFB1降解产物能在365 nm波长处发出蓝色荧光。展开更多
In vitro gas production technique（IVGPT） was used with the objective of determining the inclusion effect of live cells of two strains of Candida yeast on in vitro ruminal fermentation of two fibrous substrates. In o...In vitro gas production technique（IVGPT） was used with the objective of determining the inclusion effect of live cells of two strains of Candida yeast on in vitro ruminal fermentation of two fibrous substrates. In order to achieve this, two experiments were performed： A） using oat straw（Avena sativa） as substrate; B） using alfalfa hay（Medicabo sativa） as substrate, comparing the effect of two different strains of Candida genre, both isolated from the rumen, on the mentioned substrates. Levica 25（Candida tropicalis） yeast belongs to the culture collection of the Institute of Animal Science, Cuba, and Levazoot 15（Candida norvegensis） yeast is part of the collection of the Faculty of Zootechnology and Ecology of the Autonomous University of Chihuahua, Mexico. Both strains demonstrated their potential in activating the ruminal fermentation. They stimulated（P〈0.0001） the ruminal fermentation of the substrates under study. However, the Levazoot strain stimulated the dry matter（DM） fermentation of alfalfa in 21.43%, more than Levica 25. It is concluded that there is an influence of yeast strain and diet on the rumen environment and, therefore, it is important to select the appropriate strain in every production condition.展开更多
基金Supported by the National High-tech R&D Program of China(No.2001AA644010,2003AA644020)the National Sci-tech Supporting Program of China(2006BAJ04A06)+1 种基金the Key Project of Chinese Ministryof Education(107122)the Shanghai-Rhone Alpes Region Interna-tional Scientific Research Cooperation Fund(06SR07105)
文摘目的:鉴定一株降解黄曲霉毒素B_1(aflatoxin B_1,AFB1)的霉菌HSK8,通过优化其发酵条件提高AFB_1降解率,并初步探索其降解机制。方法:通过形态学和内部转录间隔区(internal transcribed spacer,ITS)、18S r RNA和26S r RNA序列分析对该菌株进行鉴定,并通过单因素试验对发酵条件进行优化,采用薄层层析对AFB_1降解产物进行研究。结果:经鉴定该株霉菌为夏孢生枝孢(Cladosporium uredinicola)。其发酵条件经优化确定为:发酵温度28℃、装液量75 m L/250 m L、接种量15%、发酵时间36 h、初始p H 8.0。薄层层析观察到一个不同于AFB_1的荧光斑点。结论:发酵条件优化后,AFB_1降解率从40.68%提升到68.96%,提高了69.52%;AFB1降解产物能在365 nm波长处发出蓝色荧光。
基金supported by the project CONACy T-FOMIX-CHIHUAHUA-2006-CO2 53024 (Mexico)
文摘In vitro gas production technique（IVGPT） was used with the objective of determining the inclusion effect of live cells of two strains of Candida yeast on in vitro ruminal fermentation of two fibrous substrates. In order to achieve this, two experiments were performed： A） using oat straw（Avena sativa） as substrate; B） using alfalfa hay（Medicabo sativa） as substrate, comparing the effect of two different strains of Candida genre, both isolated from the rumen, on the mentioned substrates. Levica 25（Candida tropicalis） yeast belongs to the culture collection of the Institute of Animal Science, Cuba, and Levazoot 15（Candida norvegensis） yeast is part of the collection of the Faculty of Zootechnology and Ecology of the Autonomous University of Chihuahua, Mexico. Both strains demonstrated their potential in activating the ruminal fermentation. They stimulated（P〈0.0001） the ruminal fermentation of the substrates under study. However, the Levazoot strain stimulated the dry matter（DM） fermentation of alfalfa in 21.43%, more than Levica 25. It is concluded that there is an influence of yeast strain and diet on the rumen environment and, therefore, it is important to select the appropriate strain in every production condition.
