环渤海红条毛肤石鳖种群遗传多样性研究

以线粒体细胞色素c氧化酶亚基Ⅰ(COⅠ)为遗传标记分析了环渤海红条毛肤石鳖Acanthochiton rubrolineatus 9个种群的遗传多样性及遗传结构。126只个体经PCR扩增测序获得654 bp的COⅠ基因序列,41个多态位点产生29种单倍型,单倍型多样性为0. 899±0. 013,核苷酸多样性为0. 013 3±0. 006 8。种群遗传多样性与纬度(r=-0. 808,P <0. 05)及年平均温度变异系数(r=-0. 795,P <0. 05)呈显著负相关,表明红条毛肤石鳖适应低纬度及温度稳定的海洋环境。分子方差分析表明,遗传变异主要发生在种群内(83. 26%,P <0. 001)。系统发生树与单倍型网络图没有呈现明显的谱系地理结构。种群历史动态结果显示,红条毛肤石鳖在早更新世晚期(第二温暖期)间冰期经历了种群扩张。     

Keeping fingers crossed: heterochromatin spreading through interdigitation of nucleosome arrays

Interphase eukaryotic nuclei contain diffuse euchromatin and condensed heterochromatin. Current textbook models suggest that chromatin condensation occurs via accordion-type compaction of nucleosome zigzag chains. Recent studies have revealed several structural aspects that distinguish the highly compact state of condensed heterochromatin. These include an extensive lateral self-association of chromatin fibers, prominent nucleosome linker 'stems', and special protein factors that promote chromatin self-association. Here I review the molecular and structural determinants of chromatin compaction and discuss how heterochromatin spreading may be mediated by lateral self-association of zigzag nucleosome arrays.     

Study of the Carbohydrate Specificity of Antibodies Against <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> Using the Library of Synthetic Mycoantigens

The carbohydrate specificity of antibodies obtained by immunizing laboratory animals with immunogens prepared from the Aspergillus fumigatus cell wall was analyzed using the library of biotinylated synthetic oligosaccharides. It has been shown that the main part of antipolysaccharide antibodies recognizes galactomannan in the studied immunogens with preference to its fragments containing more than two β-(1→5)-linked galactofuranosyl units. The data obtained can form the basis for the development of enzyme immunoassay for the detection of this dangerous fungal pathogen.     

一个重要的蒙古二叠纪牙形刺种

在蒙古南部Lugiingol剖面卢金格尔(Lugiingol)组下部发现牙形刺Mesogondolell aidahoensis,该地层应归入下二叠统空谷阶,而不是像以前那样归入上二叠统。     

Toward convergence of experimental studies and theoretical modeling of the chromatin fiber

Understanding the structural organization of eukaryotic chromatin and its control of gene expression represents one of the most fundamental and open challenges in modern biology. Recent experimental advances have revealed important characteristics of chromatin in response to changes in external conditions and histone composition, such as the conformational complexity of linker DNA and histone tail domains upon compact folding of the fiber. In addition, modeling studies based on high-resolution nucleosome models have helped explain the conformational features of chromatin structural elements and their interactions in terms of chromatin fiber models. This minireview discusses recent progress and evidence supporting structural heterogeneity in chromatin fibers, reconciling apparently contradictory fiber models.     

榕树须活性部位的成分研究

采用硅胶柱层析色谱和重结晶方法对榕树须95%乙醇提取物进行分离,得到8化合物,通过理化性质和波谱技术分别鉴定为:α-香树脂醇乙酸酯(1),羽扇豆醇乙酸酯(2),木栓酮(3),木栓醇(4),正三十五烷醇(5),白桦酯酸(6),β-谷甾醇(7)和豆甾-4-烯-6β-羟基-3-酮(8)。除化合物6外,其余化合物均为首次从该植物中分离得到。     

Higher-order folding of heterochromatin: protein bridges span the nucleosome arrays.

In interphase eukaryotic nuclei, chromatin is divided into two morphologically distinct types known as heterochromatin and euchromatin. It has been long suggested that the two types of chromatin differ at the level of higher-order folding. Recent studies have revealed the features of chromatin 3D architecture that distinguish the higher-order folding of repressed and active chromatin and have identified chromosomal proteins and their modifications associated with these structural transitions. This review discusses the molecular and structural determinants of chromatin higher-order folding in relation to mechanism(s) of heterochromatin formation and genetic silencing during cell differentiation and tissue development.     

感应电治疗股外侧皮神经炎临床观察

目的:探讨感应电治疗股外侧皮神经炎的临床疗效.方法:将符合纳入标准的股外侧皮神经炎患者88例随机分为治疗组和对照组,对照组在髂前上棘下10cm处进行肌肉注射维生素B 1100mg和B1 20.5mg治疗,治疗组用感应电治疗.结果:治疗一疗程后蚁走感、烧灼感、麻木感积分改善情况治疗组与对照组比较差异有显著性(p<0.01或<0.05),治疗二疗程后各症状积分改善情况治疗组与对照组比较差异有显著性(p<0.01或<0.05);治疗一疗程后及治疗二疗程后治疗组的临床疗效均优于对照组(p<0.01或<0.05).结论:感应电治疗股外侧皮神经炎疗效较好,值得临床推广.     

锂对铅引起的大鼠海马CA1区长时程增强效应（LTP）损伤的修复作用

应用离体脑片记录技术,记录大鼠海马CA1区的兴奋性突触后电位(EPSPs),研究了锂对铅引起的大鼠海马CA1区长时程增强效应(long-termpotentiation,LTP)损伤的修复作用。结果表明:对照组大鼠海马CA1区LTP幅度为194.42±14.05%(n=10);铅处理组LTP的幅度为147.06±9.55%(n=13);而锂加铅处理组LTP的幅度为193.45±14.91%(n=15)。与对照组相比,铅处理组LTP的幅度降低了47.36%,而锂几乎完全修复了铅对大鼠海马CA1区LTP幅度的损伤。锂和铅处理后对大鼠海马CA1区的双脉冲易化(paired-pulsefacilica-tion,PPF)都有一定的抑制作用,在脉冲间隔为50ms时,这种抑制效应最大:对照组为155.58±6.35%(n=7);铅暴露组为150.26±13.74%(n=8);锂加铅处理组为140.59±15.42%(n=8)。结果表明:锂对铅引起大鼠海马CA1区LTP的损伤有一定的修复作用。