政策法规·国家标准·行业标准——活化乳和乳过氧化物酶体系保存生鲜牛乳实施规范

本标准规定了生鲜牛奶(包括水牛奶，下同)挤下后，在贮存，搜集和运输到乳品加工厂期间利用乳过氧化物酶体系防止其细菌性腐坏的方法。     

cDNA Cloning and Sequence Analysis of Rice Sbel and Sbe3 Genes

Two starch-branching enzyme (SBE) in rice, is known to be a key enzyme in amylopectin biosynthesis. The cDNA of two SBE(starch-branching enzyme) genes SheI and Shed encoding SBE Ⅰ and SBE Ⅲ (two major isoforms in rice) were cloned by an improved RT-PCR technique, from a template cDNA libray, derived from the total mRNAs extracted from the immature seeds of a japonica rice Wuyunjing 7. DNA sequence analysis showed that the size of the cloned SheI and Shed cDNAs were 2490 and 2481 bp long, respectively, including their entire coding sequences. Comparison analysis indicated that the nucleotide sequence of She3 was the same as that of shed (Genbank Accession No. D16201) as reported previously. There were only four base-pairs difference,which resulted in changes of two deduced amino acids between the cloned She1 cDNA and the reported she1 (Genbank Accession No. D11082). The cloned SheI and Shed cDNAs make it possible to improve rice starch quality through genetic engineering.     

木聚糖酶产生菌的筛选及酶学性质研究

从实验室保藏的13株菌株中筛选到l株高产木聚糖酶菌株-黑曲霉2107,酶谱检测发现,该茵株产2种木聚糖酶X-1和X-2.X-1和X-2的最适反应温度都为50℃,并在30～50℃都较稳定.X-1的半失活温度50～55℃,X-2的半失活温度为55～60℃.X-1的最适pH约为5,pH 4～10较稳定;X-2的最适pH约为3和4之间,pH 2～5之间较稳定.各种金属离子对2种酶都有不同程度的抑制作用.     

蚕丝新用途研究进展

随着对蚕丝物理化学性质研究的深入，蚕丝新用途的研究得到较快的发展。本文在介绍了蚕丝新用途利用原理，介绍了蚕丝在化妆品，医药，固定化酶载体材料，食品以及再生丝和涂膜化纤表面等方面的应用和研究进展。