2,3-Dihydroxybiphenyl dioxygenase gene was first discovered in Arthrobacter sp. strain PJ3

Bacterium strain PJ3,isolated from wastewater and identified as Arthrobacter sp. bacterium based on its 16S rDNA gene,could use carbazole as the sole carbon,nitrogen and energy source. The genomic library of strain PJ3 was constructed and a positive clone JM109(pUCW402) was screened out for the expression of dioxygenase by the ability to form yellow ring-fission product. A 2,3-dihydroxybiphenyl dioxygenase(23DHBD) gene of 933 bp was found in the 3360 bp exogenous fragment of pUCW402 by GenSCAN software and BLAST analysis. The phylogenetic analysis showed that 23DHBD from strain PJ3 formed a deep branch separate from a cluster containing most known 23DHBD in GenBank. Southern hybridization confirmed for the first time that the 23DHBD gene was from the genomic DNA of Arthrobacter sp. PJ3. In order to test the gene function,recombinant bacterium BL21(pETW-8) was constructed to express 23DHBD. The expression level in BL21(pETW-8) was highest compared with the recombinant bacteria JM109(pUCW402) and strain PJ3. We observed that 23DHBD was not absolute specific. The enzyme activity was higher with 2,3-dihydroxybiphenyl as a substrate than with catechol. The substrate specificity assay suggested that 23DHBD was essential for cleavage of bi-cyclic aromatic compounds during the course of aromatic compound biodegradation in Arthrobacter sp. strain PJ3.     

一种基于Rough sets生成决策树的算法改进

介绍了决策树算法的含义和构筑方法，对基于加权平均粗糙度构造决策树算法进行改进，通过实例说明了改进算法的优势。     

浅谈神东煤炭分公司安全生产管理与持续发展

通过对安全生产的分析,结合神东煤炭分公司安全生产管理模式,论证了安全生产管理与持续发展的关系。     

我国安全生产人为事故特点及对策分析

阐述了我国安全生产的基本形势及我国安全生产面临的问题,基于我国安全事故人为因素的分析,提出了相应对策。     

枣树嫁接育苗技术

从苗圃地的选择、砧木的培育、采集和贮藏接穗、枣树嫁接方法及嫁接苗的管理等方面介绍了我国北方枣树嫁接育苗的技术。     

狭叶四照花果实性状变异分析

对分布于鄂西南的狭叶四照花果实测定果重、横径、纵径、果穗梗长、果形指数等指标,结果表明:(1)果实性状与果重的关联程度为果形指数>果实横径>果穗梗长>果实纵径;(2)产自利川市花板溪的果实性状综合评价最好.     

最小代价归并树的动态规划实现

动态规划算法广泛应用于求解最优化问题中，通过对最小代价归并树问题的研究，构造出动态递归方程，分析其最优子结构以及重叠子问题性质，从而实现动态规划的过程分析，并用C程序生成最小代价归并树验证其有效性。     

古树移植技术分析

保证大树或者古树移植成活率的关键是掌握大树移植技术，其技术主要包括大树假植技术和移栽定植技术。文章就此进行了阐述和分析。     

数据挖掘中决策树SPRINT算法探讨

本文简明扼要的介绍了数据挖掘中决策树SPRINT算法，并对其进行了一定程度上系统的分析和改进．     

基于OBS网络的一种最少冗余包的组播树共享算法

为了减少组播树共享算法(TS-MCAST)产生冗余包,有效地利用链路网络带宽,提出了一种基于光突发交换(OBS)网络的最少冗余包的组播树共享算法(LRP-MCAST-TS)。该算法实现过程中,引入了树分割规则,将满足分割条件的组播树分割成森林,然后根据重叠大小将汇聚的组播会话划分成多个组播共享类。通过理论分析,证明了LRP-MCAST-TS算法设计的正确性,达到了减少冗余包的目的。