Bidirectional regulation of dendritic voltage-gated potassium channels by the fragile X mental retardation protein

How transmitter receptors modulate neuronal signaling by regulating voltage-gated ion channel expression remains an open question. Here we report dendritic localization of mRNA of Kv4.2 voltage-gated potassium channel, which regulates synaptic plasticity, and its local translational regulation by fragile X mental retardation protein (FMRP) linked to fragile X syndrome (FXS), the most common heritable mental retardation. FMRP suppression of Kv4.2 is revealed by elevation of Kv4.2 in neurons from fmr1 knockout (KO) mice and in neurons expressing Kv4.2-3'UTR that binds FMRP. Moreover, treating hippocampal slices from fmr1 KO mice with Kv4 channel blocker restores long-term potentiation induced by moderate stimuli. Surprisingly, recovery of Kv4.2 after N-methyl-D-aspartate receptor (NMDAR)-induced degradation also requires FMRP, likely due to NMDAR-induced FMRP dephosphorylation, which turns off FMRP suppression of Kv4.2. Our study of FMRP regulation of Kv4.2 deepens our knowledge of NMDAR signaling and reveals a FMRP target of potential relevance to FXS.     

Fertilization and cytogenetic examination of interspecific reciprocal hybridization between the scallops, Chlamys farreri and Mimachlamys nobilis

Crossbreeding is a powerful tool for improving productivity and profitability in aquaculture. We conducted a pilot study of an artificial cross between two important cultivated scallops in China, Chlamys farreri and Mimachlamys nobilis, to test the feasibility of interspecific hybridization. Reciprocal hybridization experiments were performed using a single-pair mating strategy (M. nobilis ♀ × C. farreri ♂ and C. farreri ♀ × M. nobilis ♂). The fertilization of each pair was tracked using fluorescence staining of the gametes, and the chromosomes of the F1 hybrid larvae were examined via conventional karyotyping and genomic in situ hybridization (GISH). We observed moderate fertilization success in both interspecific crosses, although the overall fertilization was generally less rapid than that of intraspecific crosses. Conventional karyotyping showed that 70.4% of the viable F1 larvae in M. nobilis ♀ × C. farreri ♂ and 55.4% in C. farreri ♀ × M. nobilis ♂ comprised hybrid karyotypes (2n = 35 = 6m+5sm+11st+13t), and the results were further confirmed by GISH. Interestingly, we detected a few F1 from the M. nobilis ♀ × C. farreri ♂ cross that appeared to have developed gynogenetically. In addition, chromosome fragmentations, aneuploids and allopolyploids were observed in some F1 individuals. Our study presents evidence that the artificial cross between M. nobilis and C. farreri is experimentally possible. Further investigations of the potential heterosis of the viable F1 offspring at various developmental stages should be conducted to obtain a comprehensive evaluation of the feasibility of crossbreeding between these two scallop species.     

用平截末端使大豆根瘤菌苹果酸脱氨酶基因插入失活及电激法转化

本实验用平截末端连接法把卡那霉素抗性基因插入到大豆根瘤菌（Ｂｒａｈｙｒｈ;ｚｏｂｉｕｍｊａｐｏｎｉｃｕｍ）１１０的苹果酸脱氢酶（ｍｄｈ）基因中,致使ｍｄｈ基因失活,再通过电激法把这一重组基因转入大豆根瘤菌（Ｂｒａｈｙｒｈｉｚｏｂｉｕｍｊａｐｏｎｉｃｕｍ）２１４３中,进而探讨ｍｄｈ基因失活对大豆固氮作用的影响。     

糖皮质激素快速抑制高钾离子诱导嗜铬细胞瘤细胞内游离钙浓度升高 …

本研究应用钙离子特异光指示剂Ｆｕｒａ－２／ＡＭ,使用Ｍｉｒａｃａｌ影像系统检测了糖皮质激素对高钾离子升高嗜铬细胞瘤细胞（ＰＣ１２细胞）内游离钙浓度（［Ｃａ＾＋］ｉ）作用的影响。结果表明：（１）皮质酮抑制高钾离子诱导ＰＣ１２细胞［Ｃａ＾２＋］ｉ升高与其预处理细胞时间的长短有关,预处理３ｍｉｎ时,皮质酮开始产生抑制作用;预处理５ｍｉｎ时,其呈现的抑制作用最;预处理２５ｍｉｎ时,抑制作用基本消失。（２）     

异种血清诱发肝纤维化模型中ECM变化的研究

为了观察异种血清诱发肝纤维化过程中细胞外基质（ECM）及其生成细胞的变化规律,经腹腔注射猪血清建立大鼠肝纤维化模型,以免疫组织化学方法显示肝内胶原（Col）Ⅰ、Ⅲ、Ⅳ、Ⅴ型和纤连蛋白（Fn）及其生成细胞。结果：①Fn最早在汇管区、小叶间隔内沉积,ColⅢ、Ⅳ、Ⅴ随之增多,停止血清注射后它们都明显减弱或消失;ColⅠ沉积出现最迟,但阳性迅速增强,停止注射后仍较强;②结蛋白（Dm）阳性的肝星状细胞（HSC,原称Ito细胞）其分布和数量变化与Fn和ColⅡ基本同步,而位于汇管区及细胞间隔的原始间叶细胞（PMC）Dm（-）。提示ECM生成细胞可能来自细胞骨架表型不同的PMC和HSC,本模型由于能清晰地显示ECM及其生成细胞而更适用于肝纤维化机制及防治的研究。     

桂西壮族手皮纹的分析

本文对广西西部500例健康壮族大、中学生的手皮纹进行了观察分析,计算出各型指纹频率、指纹脊线总数、指纹频度指数、atd角度、a-b脊线数、τ距比、主线横向指数、皮纹花样出现率、掌褶纹出现率共九项基本参数,并将这些数值与汉族作了比较,桂西壮族的手纹与汉族既有相似之处,又有本民族的特点。     

Autophosphorylation-dependent protein kinase predominantly phosphorylates Ser115, thein vivo site in brain myelin basic protein

In a previous report [Yanget al., (1987a),J. Biol Chem. 262, 7034–7040], a cyclic-AMP- and calcium-independent brain kinase which requires autophosphorylation for activity was identified as a very potent myelin basic protein (MBP) kinase. In this report, the phosphorylation sites of MBP by this autophosphorylation-dependent protein kinase (autokinase) are further determined by two-dimensional electrophoresis/thin-layer chromatography, phosphoamino acid analysis, high-performance liquid chromatography, tryptic peptide mapping, sequential manual Edman degradation, and direct peptide sequencing. Autokinase phosphorylates MBP on both threonine and serine residues. Three major tryptic phosphopeptide peaks were resolved by C₁₈-reversed phase highper-formance liquid chromatography. Sequential manual Edman degradation together with direct sequence analysis revealed that FS(p)WGAEGQKPGFGYGGR is the phosphorylation site sequence (molar ratio ～1.0) for the first major phosphopeptide peak. When mapping with bovine brain MBP sequence, we finally demonstrate Ser¹¹⁵, one of thein vivo phosphorylation sites in MBP, as the major site phosphorylated by autokinase, implicating a physiologically relevant role of autokinase in the regulation of brain myelin function. By using the same approach, we also identified HRDT(p)GILDSLGR (molar ratio ～0.9) and TT(p)HYGSLPQK (molar ratio ～0.8) as the major phosphorylation site sequences in³²P-MBP phosphorylated by autokinase, further indicating that -Arg-XSer/Thr-(neutral amino acid)₃-(amino acid-containing hydroxyl group such as Ser/Glu/Asp)-(neutral amino acid)₂-may represent a unique consensus sequence motif specifically recognized by this autophosphorylation-dependent multisubstrate/ multifunctional protein kinase in the brain.     

Molecular definition of red cell Rh haplotypes by tightly linked SphI RFLPs.

The Rh blood group system of human red cells contains five major antigens D, C/c, and E/e (the latter four designated "non-D") that are specified by eight gene complexes known as Rh haplotypes. In this paper, we report on the mapping of RH locus and identification of a set of SphI RFLPs that are tightly linked with the Rh structural genes. Using exon-specific probes, we have localized the SphI cleavage sites resulting in these DNA markers and derived a comprehensive map for the RH locus. It was found that the SphI fragments encompassing exons 4-7 of the Rh genes occur in four banding patterns or frameworks that correspond to the distribution and segregation of the common Rh haplotypes. This linkage disequilibrium allowed a genotype-phenotype correlation and direct determination of Rh zygosity related to the Rh-positive or Rh-negative status (D/D, D/d, and d/d). Studies on the occurrence of SphI RFLPs in a number of rare Rh variants indicated that Rh phenotypic diversity has taken place on different haplotype backgrounds and has arisen by diverse genetic mechanisms. The molecular definition of Rh haplotypes by SphI RFLP frameworks should provide a useful procedure for genetic counseling and prenatal assessment of Rh alloimmunization.     

壳多糖酶研究的概况及最新进展

壳多糖酶专一性水解壳多糖中的β－1,4糖苷键,在自然界的碳循环中具有极其重要的意义．壳多糖酶分布广泛,功能多样,在真菌生长发育、植物抗真菌感染等生理过程中壳多糖酶均发挥重要作用．文章概述了壳多糖酶研究的现状及最新进展,介绍了壳多糖酶的分布、理化性质、催化性质、在细胞中的定位及其调控;简介了近年来真菌和植物壳多糖酶研究的动态及最新进展.