【作者】 刘玉春； 周志刚； 何夙旭； 姚斌；

【Author】 Yuchun Liu,Zhigang Zhou~*,Suxu He,Bin Yao~* Key Laboratory for Feed Biotechnology of the Ministry of Agriculture,Feed Research Institute, Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China.

【机构】 中国农业科学院饲料研究所农业部饲料生物技术重点试验室；

【摘要】 甲壳素是一种由β-(1,4)糖苷键相连的N-乙酰D-葡萄糖的聚合物,是自然界中最丰富的有机化合物之一。甲壳素作为一种结构性多糖骨架存在于甲壳中,占贝类总重量的约75%,占到贝类干重20至58%。几丁质酶能水解几丁质和甲壳素,而几丁质和甲壳素可以作为一种可再生资源利用的重要作用中发挥的。目前甲壳类废弃物被广泛用作水产养殖饲料添加剂使用。目前多种来源几丁质酶一直为人们所关注,例如来源于海洋,温泉和潮间带栖息地微生物的几丁质酶。但是还没有关于来源于河蟹养殖池塘底泥中的微生物几丁质酶的报道。河蟹通常需要7到11次脱皮才能达到成熟的平均背甲长的度,其中包括在第一年的6到8次,在第二年的4到5次和第三年的2到3次。因此高密度养殖的蟹塘底泥是一个含有大量几丁质的环境。生物体根据不同的需要能够产生多种几丁质酶。由于几丁质酶在营养和寄生方面发挥重要作用,因此使微生物特别是细菌成为几丁质酶的主要来源之一。本研究应用16S rDNA的PCR变性梯度凝胶电泳技术(PCR-DGGE技术)技术和微生物几丁质酶基因简并引物对蟹塘底泥进行了分析。研究发现蟹塘底泥中细菌主要为Chloroflexi,Proteobacteria,Bacteroidetes以及unclassified_Bacteria。通过微生物几丁质酶基因简并引物扩增共得到7种几丁质酶基因片段。通过与在GenBank的已注册序列比对,这些几丁质酶基因片段分别来源于Proteobacteria(1.27%),Bacteroidetes(45.57%),Chlorofl exi(2.53%)和Act inobacteria(50.63%)。更多还原

【Abstract】 Chitin is a linear polymer ofβ-(1,4)-linked N-acetyl D-glucosamine(GlcNAc),and represents one of the most abundant organic compounds in nature.It is a structural polysaccharide in the skeleton of crustaceans,composing approximately 75%of the total weight of shellfish,and 20 to 58%of the dry weight. Chitinase can hydrolyze chitin and play an important role in the decomposition of chitin and in the utilization of chitin as a renewable resource.At present the shell waste,especially the cost effective and valuable crab by-products,is widely utilized as aquaculture feed supplement.To make efficient use of shell, researchers have been striving to apply chitinase in aquaculture. To date,chitinases of various sources,such as marine,aquatic and intertidal hot springs habitats,have been focused.However,no studies were conducted to explore the chitinase in the crab culture pond.Generally a crab may experience 7 to 11 molts to reach mean carapace length,including 6 to 8 during the first year,4 to 5 during the second year,and 2 to 3 during the third year.Therefore the high-density crab pond is one of the most chitin-rich environments.Organisms produce chitinase for different physiological purposes.更多还原