徐州市奎河水质遗传毒理学分析

用蚕豆根尖细胞微核这一遗传毒理学技术,测定分析了市区奎河段水质的遗传学毒性,反映其污染情况。实验结果显示市区奎河段水质处于重度污染水平,部分水域的水质遗传毒理学指标很高,提示其中含有较多的污染物,对居民构成潜在的遗传毒性威胁。此外,对造成上述水域污染的原因进行了初步分析。     

蚕豆根尖细胞微核技术监测云龙湖污染的研究

本文用蚕豆根尖细胞微核技术测定了徐州市云龙湖的污染状况。数据统计分析结果表明湖区的西部与北部为重度污染,南部为中度污染,东部的污染程度介于上述两者之间。提示不同水域污染状况与其所受人类活动的影响程度密切相关。本文还对造成湖水污染的原因进行了讨论。     

PET系统时钟的设计方案探究

文章通过对目前系统时钟的几种设计方案的比较，认为有锁相环（PLL）的专用时钟系统芯片，能产生多类时钟标准、多种时钟频率和多路时钟驱动，且具有稳定的性能，成为高性能时钟系统的解决方案。     

化学疏雄对板栗产量和果实品质的影响

研究了疏雄醇对板栗产量和果实品质的影响、化学疏雄对板栗贮藏前后果实品质的变化。结果表明 :产量与疏雄率存在显著地相关性 ,化学疏雄可以提高产量 32 77% ,空蓬率降低 4 2个百分点 ,单果重提高1 7 6 % ,百蓬粒数增加 38 77% ,而且提前成熟 7～ 1 5d ,并能提高板栗果实的贮藏品质     

Mg-6Gd-Y-0.6Zr的析出行为和力学性能

利用光学显微镜、扫描电镜、X线衍射、透射电镜等手段研究添加1％Y(质量分数,下同)对Mg-6Gd-0.6Zr 合金析出行为和力学性能的影响.研究结果表明:添加合金元素Y能大大促进Mg-6Gd合金的时效析出;具有高过饱和度的Mg-6Gd-Y-0.6Zr合金在200℃表现出显著的时效硬化现象;随着时效温度的升高,晶界周围析出相极度粗化并且β'相体积分数降低、分布不均;尤其在250℃峰时效的组织中观察到Mg-6Gd合金所不具备的β'相.200℃时效72 h后,合金获得优异的力学性能,其室温抗拉强度、屈服强度和伸长率分别为354MPa,292MPa和9.5％,250℃时抗拉强度、屈服强度和伸长率分别为307MPa,220MPa和13.6％.     

Endogenous animal toxin-like human β-defensin 2 inhibits own K<Superscript>+</Superscript> channels through interaction with channel extracellular pore region

Human potassium channels are widely inhibited by peptide toxins from venomous animals. However, no human endogenous peptide inhibitor has been discovered so far. In this study, we demonstrate for the first time using electrophysiological techniques, that endogenous human β–defensin 2 (hBD2) is able to selectively and dose-dependently inhibit the human voltage-gated Kv1.3 channel at picomolar peptide concentration. The co-immunoprecipitation assays further supported the selective binding of hBD2 to Kv1.3 channel. Using mutagenesis experiments, we found that the outer pore domain of Kv1.3 channel was the binding site of hBD2, which is similar to the interacting site of Kv1.3 channel recognized by animal toxin inhibitors. The hBD2 was able to suppress IL-2 production through inhibition of Kv1.3 channel currents in human Jurkat cells, which was further confirmed by the lack of hBD2 activity on IL-2 production after Kv1.3 knockdown in these cells. More interestingly, hBD2 was also found to efficiently inhibit Kv1.3 channel currents and suppress IL-2 production in both human primary CD3⁺ T cells and peripheral mononuclear cells from either healthy donors or psoriasis patients. Our findings not only evidenced hBD2 as the first characterized endogenous peptide inhibitor of human potassium channels, but also paved a promising avenue to investigate newly discovered function of hBD2 as Kv1.3 channel inhibitor in the immune system and other fields.     

硫酸铈诱导果蝇氧化应激及细胞凋亡的研究

本实验主要研究了稀土硫酸铈（Ce（SO4）2）对果蝇氧化应激生物标记物和细胞凋亡的影响.果蝇培养在不同质量浓度（1,4,16,64,256,1 024 mg/L）的硫酸铈培养基中,分别测定其SOD,CAT和脂质过氧化产物（即MDA含量）,同时用彗星电泳和体外切割DNA实验来检测果蝇细胞中DNA损伤程度,用DNA Laddering法和TUNEL法测定稀土元素Ce对果蝇细胞凋亡的影响.与对照组相比,当Ce（SO4）2质量浓度低于16 mg/L时,果蝇体内SOD和CAT活性显著增加,MDA含量变化不明显;而当Ce（SO4）2质量浓度高于16 mg/L时,SOD和CAT活性明显下降,MDA含量上升.彗星电泳的结果表现为随着硫酸铈剂量的递增,果蝇中肠细胞的彗星率、彗星尾长和Olive尾矩增加,并表现为明显的剂量效应关系.果蝇体外实验结果表明,硫酸铈能打断DNA,使其片段化;同时,TUNEL结果显示果蝇中肠细胞呈现凋亡细胞的特征性蓝绿色颗粒,但DNA琼脂糖电泳没有表现出细胞凋亡特征性的梯形条带图谱.硫酸铈诱导果蝇的氧化应激可以使果蝇中肠细胞SOD和CAT活性降低,MDA含量上升,使中肠细胞出现凋亡特征.由此推断,硫酸铈可诱导果蝇细胞中遗传物质的损伤,对果蝇有一定的氧化毒性和遗传毒性作用．     

FISH analysis of the integration patterns in transgenic rice co-transformed by microprojectile bombardment

Using multi-color fluorescencein situ hybridization (FISH), we localized transferredbarnase-ps1 andpHctinG DNA sequences onto chromosomes of two transgenic rice plants, named Q12 and Q13, both of which were produced by micro-projectile bombardment. In both Q12 and Q13, each detected cell showed 2–3 signal spots on their chromosomes respectively. The signals of bothbarnase-ps1 andpHctinG were mostly detected in the adjacent chromosomal sites in which their signals were overlapped and could be recognized by the signal color on the metaphase chromosomes. Fiber FISH further demonstrated that the multiple copies in each of the two DNA sequences distributed adjacently on the DNA fiber in Q13. Combined with the results of Southern hybridization, the possible integration patterns in transgenic rice co-transformed by micro-projectile bombardment have been discussed.     

中华大蟾蜍与无蹼壁虎冬眠前后含水率的比较

冬眠后，无蹼壁虎的总含水率及各部分的含水率均比冬眠前有所降低，躯体含水率下降显著；大蟾蜍的总含水率及各部分的含水率均比冬眠前有所上升，其中脂肪体及内脏的含水率上升显著．二者在含水率的变化上存在显著差异．这是由于二者生存环境、物种及各自的冬眠环境的差异造成的．     

板栗雄花对树体营养消耗的影响

利用常规的化学分析方法，对板栗雄花消耗水分、干物质、氨基酸等营养成分定量地进行了研究，为板栗的疏雄增产提供理论依据