不同化学杂交剂(CHA)对小麦花药同工酶影响的研究

在小麦叶枕距±2cm时,喷施4种不同化学杂交剂（CHA）后,分别取小孢子处于不同发育阶段的花药,进行过氧化酶（POD）、淀粉酶（Amy）和酯酶（Est）等同工酶的分析。研究表明：在小孢子母细胞减数分裂期,处理2、3和4三种CHA对POD的A1、A2;B2、B4和B5,C1、C2和C3同工酶带的活性均有明显的抑制作用;处理5除去对A1和A2表现抑制外,对其他酶带的活性均有增强作用。在单枚早期,处理2和3的A、B和C区POD同工酶活性均明显低于对照;处理4和5上述各区POD同工酶活性却明显高于对照。在上述两个发育时期,处理2对Amy1区酶活性有增强作用,而处理3、4和5对该区酶活性却表现了专一性的抑制。各处理对Est同工酶A区和B区的酶活性主要表现为抑制。实验结果表明,不同的CHA均通过干扰花药的物质和能量代谢而导致雄性生理性不育。     

基于多目标灰色局势决策的三峡库区防护林类型空间优化配置

基于2007年Landsat TM遥感影像和影响防护林的主导环境因子,对三峡库区的森林立地进行分类,并通过选取水源涵养量、生物量和林分生产力3个指标,利用多目标灰色局势决策模型对库区现有的针叶林、阔叶林、针阔混交林和灌木林4种防护林类型进行空间优化配置.结果表明： 2007年,三峡库区森林立地可划分为40种类型;空间配置优化后,研究区针叶林、阔叶林、针阔混交林和灌木林的面积比例分别为32.55%、29.43%、34.95%和3.07%.与优化前相比,优化后针叶林和灌木林的面积比例分别减少了8.79%和28.55%,阔叶林和针阔混交林分别增加了10.23%和27.11%.通过防护林类型的空间优化,三峡库区整体的水源涵养能力、生物量和林分生产力分别增加14.09×10⁸ m³、0.35×10⁸ t和1.08×10⁶ t.     

Biodegradability of tannin-containing wastewater from leather industry

Tannins occur commonly in the wastewaters from forestry, plant medicine, paper and leather industries. The treatment of this kind of wastewaters, including settling and biodegradation, is usually difficult because tannins are highly soluble in water and would inhibit the growth of microorganisms in activated sludge. The objective of this study is to investigate biodegradability of tannin-containing wastewaters, so as to characterize the pollution properties of such wastewaters and provide a reference for their biological treatment in wastewater treatment plants. The research was typified by using the wastewater collected from vegetable tanning process in leather industry. A model was developed to describe the activated sludge process, and the biodegradation kinetics of vegetable tanning wastewater (VET wastewater) was studied. It was found that the biodegradability of tannin-containing wastewater varies heavily with the content of tannins in wastewater. The biodegradation of VET wastewater with tannin content around 4,900 mg/l occurred inefficiently due to the inhibition of tannins to the activated sludge process, and only 34.7% of biodegradation extent was reached in 14 days of incubation. The optimal biodegradability of VET wastewater was observed when its tannin content was diluted to 490 mg/l, where the COD and tannin removals reached 51.3% and 45.1% respectively in 6 days. Hence, it is suggested that a proper control of tannin content is necessary to achieve an effective biodegradation of tannin-containing wastewaters in wastewater treatment plants.     

粳稻SRAP分子标记遗传群的构建与分析

用超级稻品种‘沈农606’和普通粳稻‘丽江新团黑谷’为亲本杂交获得的102份F_2代单株,通过SRAP分子标记遗传分析,构建了包含14个连锁群,由129个多态性位点组成的水稻连锁图谱,此图谱覆盖基因组长度1671.5 cM,平均图距13.0 cM。连锁群上有17.2%的多态性位点表现偏分离,偏分离标记在连锁群上存在热点区域。     

不同性别类型黄瓜ACC合酶基因的单核苷酸多态性标记和酶切扩增长度多态性标记

黄瓜的性别分化与乙烯密切相关,1-氨基环丙烷-1-羧酸(ACC)合酶是乙烯生物合成过程中的关键酶.根据ACC合酶基因家族的保守序列设计PCR引物,从8个不同性别类型(雌雄同株、强雌性和全雌性)黄瓜品种中克隆了长度为1188bp的ACC合酶基因(CS-ACS2)片段(GenBank登记号为:DQ115884～DQ115886和DQ115875～DQ115879).经测序分析,3个雌雄同株性别类型品种的序列完全相同.与之相比,5个强雌性和全雌性品种中存在8个单核苷酸多态性(SNPs)标记,SNPs标记为4个A←→G和4个T←→C之间的转换.在8个SNPs中,有1个SNP位于内含子区域,其余7个SNPs都位于外显子区域.在7个位于外显子区域的SNPs中,有3个为非编码区的SNPs,4个为cSNPs.而在4个cSNPs中,有3个导致了编码的氨基酸序列改变.研究结果表明,与雌雄同株性别类型相比,雌性系中均存在单核苷酸的变异,这提示ACC合酶基因CS-ACS2的单核苷酸变异可能与黄瓜雌性系的发生形成有关.另一方面,根据SNP多态性还发展了一个酶切扩增长度多态性(CAPS)标记C-MT700.利用CAPS标记C-MT700能将强雌性优良品种MT-705与其他黄瓜品种相区别,该标记在黄瓜育种生产上具有一定的应用价值.此外,研究获得的SNPs标记和CAPS标记丰富了黄瓜的分子标记种类.     

长白落叶松（Larix olgensis）工业人工林的模拟间伐

应用马尔柯夫过程理论,在获得林分直径转移概率的基础上,采用间伐最小径阶林木,最大径阶林木,中间径阶林木三种间伐方式,在保留不同密度情况下对长白落叶松工业人工林进行模拟间伐,提出了适宜的保留密度和相应的抚育间伐对象。结果表明：马尔柯夫过程确能反映长白落叶松工业人工林的直径转移过程,利用马尔可夫过程理论对长白落叶松工业人工林进行模拟间伐实现了依据培育时间来确定间伐方法和措施,提高了长白落叶松工业人工林经营管理的精准性;长白落叶松工业人工林成林后的间伐无论从培育森林方面,还是从取得木材、加大林分收益方面考虑,都应该以间伐小径阶的林木为主,注重培育I、II级木,间伐III, IV级木;20～25 a长白落叶松工业人工林间伐后的保留经营密度以0.7为宜。     

Lyciumamide A,a dimer of phenolic amide,protects against NMDA-induced neurotoxicity and potential mechanisms in vitro

Journal of Molecular Histology - Currently, the excessive activation of N-methyl-D-aspartate receptors (NMDARs) is considered to be a crucial mechanism of brain injury. Lycium barbarum A (LyA) is a...     

毕氏海蓬子SbDREB基因的克隆与表达分析研究

以毕氏海蓬子的基因组为模板,通过PCR技术扩增到一个编码DREB蛋白AP2保守结构域的基因片段;根据该片段序列设计引物,以毕氏海蓬子经NaCl处理的植株肉质茎cDNA为模板,应用RACE技术获得该基因的cDNA全长,命名为SbDREB(GenBank登录号:JF894301)。SbDREB基因cDNA全长1206bp,包含一个编码284个氨基酸的完整开放阅读框。对氨基酸序列比对分析表明,该蛋白在靠近N端具有典型的AP2/EREBP保守结构域,且该结构域与一些高等植物DREB类转录因子的AP2区域具有高度同源性。进化树分析表明SbDREB属于DREB亚家族中的A-6亚族。实时荧光定量PCR结果显示:干旱、高盐和ABA能够诱导其表达,而低温则使其表达下调,表明该基因在毕氏海蓬子植株对干旱、盐和低温等非生物胁迫的应答中起作用。     

Crystallization and main-chain structure of neutral protease from Streptomyces caespitosus

A neutral protease, i.e., a zinc-containing metalloendoprotease from Streptomyces caespitosus, has been crystallized using acetone as a precipitating agent. The crystals diffract to better than 1.5 A resolution when a rotating anode X-ray generator is used as an X-ray source. Protein phase angles were calculated by the multiple isomorphous replacement method using two heavy-atom derivatives (HgCl2 and CH3HgCl). A 6 A resolution electron density map clearly showed molecular boundaries. Although its amino acid sequence is not known, the folding pattern of the polypeptide chain could be traced on a 2.5 A resolution electron density map. A large cleft, which is located on the molecular surface, was proved to be the active site of the enzyme by structure analyses of inhibitor-complex crystals. The highest electron density peak, which corresponds to the cleft, was assigned to a catalytically essential zinc atom on difference Fourier synthesis between native and EDTA-soaked crystals.