Comparison of the community structure of planktonic bacteria in ballast water from entry ships and local sea water in Xiamen Port

In this study, the bacterial community structures in samples of ballast water collected from a ship from Singapore and of local sea water collected from Xiamen Port were compared using restriction fragment length polymorphism (RFLP) and 16S rDNA sequence analysis. Except for dominant α-Proteobacteria that are common to both systems, the bacterial community structures of the two systems were quite different. Most of the clones derived from the different systems were grouped into different phylogenetic clusters, and the sys-tems share only one common RFLP pattern. The ballast water, which is likely from clean offshore waters, contains sequences specific to α- and γ-Proteobacteria. Phylogenetic analysis revealed that the ballast water contained sequences belonging to attached bacteria and bacteria commonly found in the open sea, as well as many novel sequences. In addition, no known pathogenic bacteria were detected in the ballast water samples. Conversely, water samples from Xiamen Port were apparently affected by the near shore environments.Specifically, in addition to α- and γ-Proteobacteria, water from Xiamen Port contained β- and δ-Proteobacteria, Synechococcus, Bacter-oidetes and Actinobacteria, which are common in coastal environments. Additionally, four pathogenic bacterial sequences and one plas-mid sequence of a potential red tide forming alga were detected in the water from Xiamen Port, which suggests that the local sea water is polluted. The results of this study can be used as background information to assess the risk associated with the introduction of non-indig-enous species to local systems and to establish ballast water management systems.     

Evolutionary analysis of allotetraploid hybrids of red crucian carp × common carp, based on ISSR, AFLP molecular markers and cloning of cyclins genes

The allotetraploid hybrids of red crucian carp x common carp are the first reported artificially cultured polyploid fish with bisexual fertility and stable inheritance in vertebrate. Using ISSR and AFLP markers and the cyclins genes, the genomes and cyclin gene sequence changes were analyzed between the allotetraploid hybrids and their parents. The results indicated that the allotetraploids inherited many genetic characteristics from their parents and the genetic characteristics were stable after 15 generations. However, the allotetraploids had a closer genetic relationship with their original female parents and represented a bias toward the maternal progenitor. DNA fingerprinting analysis showed that the allotetraploids had undergone sequences deletion from their original parents and that the deleted sequences were mostly from the male parent＇s genome. Some non-parental bands were found in the allotetraploid hybrids. Sequences analysis of the cyclin A1 and B1 genes showed nonsynonymous substitutions of single nucleotides in codons that were different from their original parents, leading to non-parental amino acid loci. We speculate that the non-additivity in the allotetraploids, compared with their progenitors, could be an adjustment to the genomic shock from heterozygosity and polyploidy, allowing maintenance of genetic stability.     

预制破片对屏蔽炸药冲击引爆研究*

针对破片斜冲击状态下引爆屏蔽固体炸药问题开展了研究。从理论上建立了与冲击角度相关的冲击压力计算方法。结合炸药起爆判据,可确定炸药冲击起爆的临界速度。采用Lee-Tarver点火增长模型和LS-DYNA仿真软件,对破片斜撞击屏蔽装药冲击起爆过程进行了数值模拟。利用升-降法确定了临界起爆速度,验证了理论模型的有效性;并分析了破片材料、入射角和靶板厚度对冲击起爆JO—9195固体炸药临界速度的影响。结果表明:理论计算和数值模拟误差不超过5.98%,吻合较好,表明所建立的理论计算方法是有效的。在相同条件下,钨合金破片相对于钢质和铜质破片临界起爆速度低;随着入射角和靶板厚度增加,冲击起爆的临界速度也随之增大。     

活性破片终点毁伤威力试验研究

针对活性破片终点毁伤威力问题,采用试验研究的方法,分析了活性破片的击穿能力、引燃能力和引爆能力. 结果表明,2.5 g活性破片在870 m/s以上碰撞速度条件下,能可靠击穿8 mm厚LY12硬铝,侵孔直径约为自身直径的1.6~2.0倍;10 g活性破片以大于800 m/s左右速度击穿10 mm厚LY12硬铝板后,可靠引燃航空煤油;10 g活性破片以大于960 m/s左右速度击穿6 mm厚A3钢板后,可靠引爆战斗部装药. 结合活性破片击穿能力可知,活性破片贯穿一定厚度靶板并达到其起爆阈值,就能引燃燃油或引爆装药.      

钢筋混凝土板震塌碎片特性试验

为研究钢筋混凝土板震塌碎片速度、质量和毁伤特性,对三种厚度靶板开展了14炮次爆炸试验,通过图像捕捉法获取了碎片初始速度,依据量纲分析,建立了速度与震塌系数的定量关系.对试验结果统计分析发现,有限厚度板(≤300 mm)无论发生何种破坏类型(震塌、贯穿、冲切),产生的单个碎片质量均以60 g以下为主,其中30 g以下碎片主要为单粒石子,30 ～ 60 g碎片以砂石胶结体为主,且震塌系数越小,单粒碎片尺度越小、质量越小.对等效模拟物的毁伤状态分析表明,混凝土类单粒碎片无法对25 mm厚松木板形成有效贯穿,松木板的损伤主要表现为冲击伤,板表面呈现较多冲击压痕.由于碎片自身强度有限,部分碎片对目标撞击过程中易出现碎裂或者粉碎,从而导致无法继续侵入.虽然单粒碎片无法侵入松木板,但其数量较多、单位面积上密度较大,易对人员造成大面积表皮伤.碎片束(碎片云)对目标物的持续冲击时间可达200～500 ms,可使目标产生损伤累积,最终导致目标物严重损毁或者人员伤亡.     

单抗Fab片段与抗癌抗生素C1027偶联物对裸鼠移植人肝癌的治疗作用

抗人肝癌单抗3A5用氯化汞合木瓜蛋白酶消化,经SDS-PAGE、ELISA方法检测证实得到Fab活性片段。单抗3AS及Fab片段与抗癌抗生素C1027偶联,得到3A5-C1027和Fab-C1027偶联物。克隆生成测定对肝癌细胞具有极强的杀伤作用,C1027、3A5-C1027和Fab-C1027的IC50值分别为6.5 x10~(-16)、4.2×10~(-14)M和8.6×10~(-16) M。 Fab-C1027对人咽上皮癌细胞与靶细胞的杀伤活性相比,两者相差32倍,呈选择性杀伤作用。观察C1027、Fab-C1027对移植人肝癌裸鼠的治疗作用,其抑瘤率分别为59％和85％。在可耐受剂量下,C1027对人肝癌有明显的抑制作用,而Fab-C1027显示更强的抑制作用。     

Effects of Chlorophyll Availability on Fluorescence Components of Photosystems in the ORF469-Deletion Mutant of Cyanobacterium

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｃｙａｎｏｂａｃｔｅｒｉａ ,ｔｗｏ ｐａｔｈｗａｙｓｏｆ ｐｒｏｔｏ ｃｈｌｏｒｏｐｈｙｌｌｉｄｅ (Ｐｃｈｌｉｄｅ)ｒｅｄｕｃｔｉｏｎａｎｄｃｈｌｏｒｏｐｈｙｌｌ(Ｃｈｌ)ｂｉｏｓｙｎｔｈｅｓｉｓａｐｐｅａｒｔｏｅｘｉｓｔ:ｏｎｅｉｓｌｉｇｈｔ ｄｅｐｅｎｄｅｎｔ ,ｔｈｅｏｔｈｅｒｉｓｌｉｇｈｔ ｉｎｄｅｐｅｎｄｅｎｔ[1,2 ] .Ａｔｌｅａｓｔｔｈｒｅｅ ｐｏｌｙｐｅｐｔｉｄｅｓａｒｅｉｎｖｏｌｖｅｄｉｎｔｈｅｌｉｇｈｔ ｉｎｄｅｐｅｎｄｅｎｔｐａｔｈｗａｙ .Ｏｎｅｏｆｔｈｅｓｅｐ…     

甲苯二异氰酸酯对小鼠遗传毒性的研究

考察受试物甲苯二异氰酸酯(TDI)是否具有遗传毒性.通过小鼠染色体畸变实验,和姐妹染色单体交换实验进行检测.在给予甲苯二异氰酸酯1/16LC50和1/8LC50剂量的染毒组对染色体畸变率和姐妹染色单体交换率无显著性影响(P>0 05),而1/4LC50以及1/2LC50剂量的染毒组对染色体畸变率和姐妹染色单体交换率有非常显著的影响(P<0 01),结果显示,甲苯二异氰酸酯具有一定的遗传毒性.     

松材线虫与拟松材线虫RAPD检测技术

采用RAPD技术对松材线虫和拟松材线虫进行了检测研究,从140个随机引物中筛选出引物OPK09与引物组合OPC18 OPN18。引物OPK09对12个松材线虫株系扩增出一条约2400bp左右的特异片段,引物组合OPC18 OPN18对10个拟松材线虫株系扩增出一条970bp左右的特异片段。实验表明,引物OPK09与引物组合OPC18 OPN18具有特异性强、灵敏度高的优点。用这两组引物可以快速、准确鉴定松材线虫和拟松材线虫。     

DNA序列拼接中重复序列屏蔽的一种新方法

针对序列拼接中的重复序列问题,提出了一种基于快速沃尔什变换的重复序列屏蔽方法．根据快速沃尔什变换的特点,快速给出重复序列所在的可能位置信息,从而快速识别重复序列且加以屏蔽．该方法不仅识别重复序列的错误率低而且大大降低了cPu运行时间,计算也简单易行,最后给出了模拟分析．