外源亚精胺对NaCl胁迫下毕氏海蓬子光合参数和叶绿体超微结构的影响

在0、100、300、500和700 mmol·L-1NaCl胁迫条件下比较了喷施0.1mmol·L-1亚精胺(Spd)对毕氏海蓬子(Salicomia bigelovii Torr.)幼苗叶绿素含量、净光合速率、气孔导度、胞间CO2浓度和叶绿体超微结构的影响.结果表明:毕氏海蓬子的叶绿素含量、净光合速率和气孔导度均呈低浓度条件下(0、100和300 mmol·L-1NaCl)升高、高浓度条件下(500和700 mmol·L-1NaCl)降低的趋势,在300 mmol·L-1 NaCl胁迫条件下达到最高值:胞间CO2浓度则呈低浓度NaCl胁迫条件下降低、500 mmol·L-1NaCl条件下升高、700 mmol·L-1NaCl条件下略降低的趋势;在0～500 mmol·L-1NaCl胁迫条件下叶绿素a/b值变化不明显,但在700 mmol·L-1NaCl条件下急剧降低.在低浓度NaCl胁迫条件下,叶绿体整体膨胀,类囊体片层结构松散,但叶绿体和类囊体结构仍保持完整;而经500和700mmol·L-1NaCl处理后,叶绿体超微结构被严重破坏,叶绿体膜结构破裂、类囊体结构松散呈放射状、有些叶绿体完全解体.而在相应的NaCl胁迫条件下喷施0.1 mmol·L-1Spd,毕氏海蓬子的叶绿素含量、净光合速率、气孔导度和胞间CO2浓度虽然也呈现出相同的变化趋势,但其数值均显著高于对照(未喷施Spd);且叶绿体超微结构的损伤程度也轻于对照.研究结果说明:喷施外源Spd能够减缓NaCl胁迫对毕氏海蓬子的伤害作用.     

The atlas of RNase H antisense oligonucleotide distribution and activity in the CNS of rodents and non-human primates following central administration

Antisense oligonucleotides (ASOs) have emerged as a new class of drugs to treat a wide range of diseases, including neurological indications. Spinraza, an ASO that modulates splicing of SMN2 RNA, has shown profound disease modifying effects in Spinal Muscular Atrophy (SMA) patients, energizing efforts to develop ASOs for other neurological diseases. While SMA specifically affects spinal motor neurons, other neurological diseases affect different central nervous system (CNS) regions, neuronal and non-neuronal cells. Therefore, it is important to characterize ASO distribution and activity in all major CNS structures and cell types to have a better understanding of which neurological diseases are amenable to ASO therapy. Here we present for the first time the atlas of ASO distribution and activity in the CNS of mice, rats, and non-human primates (NHP), species commonly used in preclinical therapeutic development. Following central administration of an ASO to rodents, we observe widespread distribution and target RNA reduction throughout the CNS in neurons, oligodendrocytes, astrocytes and microglia. This is also the case in NHP, despite a larger CNS volume and more complex neuroarchitecture. Our results demonstrate that ASO drugs are well suited for treating a wide range of neurological diseases for which no effective treatments are available.     

Synthesis and Antiviral Activities of 1,3-Oxathiolanyl Nucleosides with 5-Hydroxymethyl Substituent

Abstract

Novel 1,3-oxathiolanyl pyrimidine nucleosides with 5-hydroxymethyl substituent were synthesized starting from _d-mannose and evaluated for antiviral activities against HIV-1, HSV type 1,2 and HCMV.     

降低mRNA差异显示技术假阳性率的一种方法

为了探讨降低mRNA差异显示技术假阳性率的方法 ,进一步提高此技术的可靠性 ,提取了手术切除肝癌及非癌肝组织成对标本的总RNA ,逆转录获得cDNA片段 ,以mRNA差异显示方法筛选差异表达基因 ,选取较明显的一条差异表达条带 ,行进一步PCR扩增 .分别对PCR产物及其经TA克隆后随机挑选的 6个单克隆质粒DNA进行序列分析 ,并通过GenBank BLAST数据库进行序列的同源性比较 ,以Northern杂交予以来源确认 .自 72 0余条扩增条带中共选出 2 8条差异条带 .序列分析及同源性比较表明 ,所选择条带的PCR产物为一可能的新基因片段 ;而随机选择的 6个TA克隆质粒DNA中 ,有 4个为同一已知基因片段 ,一个为另一已知基因片段 ,一个为一可能的新基因片段 .同源性比较表明 ,PCR产物直接测序所得序列与TA克隆质粒DNA的 6个片段不具同源性 .结果表明 ,mRNA差异显示条带可能由 1条以上分子量相似的片段构成 ,直接对PCR产物行序列分析并以其为探针进行Northern杂交 ,是导致出现假阳性片段的原因之一 .将PCR产物进行TA克隆 ,对单克隆质粒DNA进行序列分析并以其为探针进行Northern杂交 ,可能是解决此问题的一种较好方法 .     

Agriculture driving male expansion in Neolithic Time

正Dear Editor,Dispute between agriculture and initial population expansion in Neolithic Time has been in suspense for a long time.Agriculture first appeared in the Fertile Crescent of West Asia about 11–12 thousand years ago(kya),with domesticating few wild plant and animal species.There is also evidence of the cultivation of rice and millet in Yangtze and Yellow River Basins of China approximately 9 kya.During the subsequent times between 9 and 4 kya,agriculture arose     

Observation on the initial inoculum source and dissemination of Entomophthorales-caused epizootics in populations of cereal aphids

A total number of 1092 migratory alates were trapped from air in wheat grown area of Yuanyang County, Henan Province from early April through May 2002 in order to confirm the source and dissemination of entomophthoralean inocula to cause epizootics of cereal aphids. Those included 415 Sitobion avenae, 642 Rhopalosiphum padi, 22 Metopolophium dirhodum, and 13 Schizaphis graminum. The trapped alates were daily collected and individually reared for 7 days on wheat plants in laboratory. Of those 341 alates died of fungal infection, taking 31.2% in the trapped alates. These included 224 S. avenae, 106 R. padi, 8 M. dirhodum, and 3 S. graminum. Deaths of all infected alates occurred during the first 5 days and 78.9% of the deaths occurred within the first 3 days. Individual examination under microscope proved that all deaths were attributed to entomophthoralean fungi. Of those Pandora neoaphidis accounted for 84.6%, Conidiobolus obscurus for 9.9%, and Entomophthora planchoniana for 5.5%. Four alate deaths die     

离子交换高效液相层析法测定腺苷酸环化酶活性

用离子交换高效液相层析（ＨＰＬＣ）分离并同步测定脑组织腺苷酸环化酶（ＡＣ）反应生成的ｃＡＭＰ,从而直接测定ＡＣ活性。１００℃加热１ｍｉｎ终止ＡＣ反应后,混合物在０℃放置２ｈ。在此期间,反应体系中残留的ＡＴＰ水解酶将反应混合物中大部分剩余的ＡＴＰ水解除去。用二氯甲烷抽提除去罂粟碱等干扰物质,使混合物中的ｃＡＭＰ同蓁物质在Ｓｈｉｍ－Ｐａｋ ＷＡＸ－１阴离子交换ＨＰＬＣ术上基线分离,并可定量测定,用此方     

提高糖基化的酶蛋白可结晶性研究 *

糖基化修饰是一类重要的翻译后修饰,对蛋白质的表达调控,折叠,分泌和功能等方面发挥着关键作用.酶是由活细胞产生的具有高度特异性和高效催化性的生物催化剂,酶的糖基化修饰对其生物催化特性和稳定性具有重要影响.研究糖基化修饰对酶蛋白的影响机制需要获取糖基化酶蛋白的结构,X-射线晶体衍射学是获得结构信息的重要技术手段,在糖基化酶蛋白的晶体衍射研究中,复杂,多样,不均一的糖基化修饰限制了该类酶的晶体生长,这是影响糖基化的酶蛋白结构解析的关键瓶颈问题.因此,如何提高糖基化的酶蛋白可结晶性是当前蛋白质结构研究的热点和难点.糖苷酶的去糖基处理,糖基转移酶抑制剂的引入和异源表达体系优化等手段都是当前研究领域提高糖基化的酶蛋白可结晶性的重要策略,这些手段可以在避免损害糖基化的酶蛋白稳定性和催化活性的同时提高其均一性.