Smart phone, smart science: how the use of smartphones can revolutionize research in cognitive science

Investigating human cognitive faculties such as language, attention, and memory most often relies on testing small and homogeneous groups of volunteers coming to research facilities where they are asked to participate in behavioral experiments. We show that this limitation and sampling bias can be overcome by using smartphone technology to collect data in cognitive science experiments from thousands of subjects from all over the world. This mass coordinated use of smartphones creates a novel and powerful scientific "instrument" that yields the data necessary to test universal theories of cognition. This increase in power represents a potential revolution in cognitive science.     

Functional architecture of the inner pore of a voltage-gated Ca2+ channel

The inner pore of voltage-gated Ca2+ channels (VGCCs) is functionally important, but little is known about the architecture of this region. In K+ channels, this part of the pore is formed by the S6/M2 transmembrane segments from four symmetrically arranged subunits. The Ca2+ channel pore, however, is formed by four asymmetric domains of the same (alpha1) subunit. Here we investigated the architecture of the inner pore of P/Q-type Ca2+ channels using the substituted-cysteine accessibility method. Many positions in the S6 segments of all four repeats of the alpha1 subunit (Ca(v)2.1) were modified by internal methanethiosulfonate ethyltrimethylammonium (MTSET). However, the pattern of modification does not fit any known sequence alignment with K+ channels. In IIS6, five consecutive positions showed clear modification, suggesting a likely aqueous crevice and a loose packing between S6 and S5 segments, a notion further supported by the observation that some S5 positions were also accessible to internal MTSET. These results indicate that the inner pore of VGCCs is indeed formed by the S6 segments but is different from that of K+ channels. Interestingly some residues in IIIS6 and IVS6 whose mutations in L-type Ca2+ channels affect the binding of dihydropyridines and phenylalkylamines and are thought to face the pore appeared not to react with internal MTSET. Probing with qBBr, a rigid thiol-reactive agent with a dimension of 12 angstroms x 10 angstroms x 6 angstroms suggests that the inner pore can open to >10 angstroms. This work provides an impetus for future studies on ion permeation, gating, and drug binding of VGCCs.     

Heme oxidation in a chimeric protein of the alpha-selective Neisseriae meningitidis heme oxygenase with the distal helix of the delta-selective Pseudomonas aeruginosa

Heme oxygenases from the bacterial pathogens Neisseriae meningitidis (nm-HO) and Pseudomonas aeruginosa (pa-HO) share significant sequence identity (37%). In nm-HO, biliverdin IXalpha is the sole product of the reaction, whereas pa-HO yields predominantly biliverdin IXdelta. We have previously shown by NMR that the in-plane conformation of the heme in pa-HO is significantly different from that of nm-HO as a result of distinct interactions of the heme propionates with the protein scaffold [Caignan, G. A., Deshmukh, R., Wilks, A., Zeng, Y., Huang, H. W., Moenne-Loccoz, P., Bunce, R. A., Eastman, M. A., and Rivera, M. (2002) J. Am. Chem. Soc. 124, 14879-14892]. In the report presented here, we have extended these studies to investigate the role of the distal helix by preparing a chimera of nm-HO (nm-HOch), in which distal helix residues 107-142 of nm-HO have been replaced with the corresponding residues of the delta-regioselective pa-HO (112-147). Electronic absorption spectra, resonance Raman and FTIR spectroscopic studies confirm that the orientation and hydrogen bonding properties of the proximal His ligand are not significantly altered in the chimera relative those of the wild-type proteins. The catalytic turnover of the nm-HOch-heme complex yields almost exclusively alpha-biliverdin and a small but reproducible amount of delta-biliverdin. NMR spectroscopic studies reveal that the altered regioselectivity in the chimeric protein likely stems from a dynamic equilibrium between two alternate in-plane conformations of the heme (in-plane heme disorder). Replacement of K16 with Ala and Met31 with Lys in the chimeric protein in an effort to tune key polypeptide-heme propionate contacts largely stabilizes the in-plane conformer conducive to delta-meso hydroxylation.     

Efficient, pH-dependent RNA ligation by the VS ribozyme in trans

The VS ribozyme acts as a very efficient ligase in trans when the 5' cleavage product is prevented from dissociation by an extended helix Ia in the substrate. Provided that the length of this helix is >or=10 bp, the substrate becomes approximately 80% ligated by the ribozyme acting in trans. Most of the nucleotides that have been shown to be important for cleavage are similarly important for ligation, including the critical A756 of the active site. The exception to this is C755. The variant ribozyme C755A has almost normal cleavage activity, whereas the rate of ligation is reduced 70-fold. It is therefore likely that this nucleotide plays a specific role in the organization of the termini of the ligation substrates. We have found that the rate of the trans ligation reaction depends on pH, corresponding to the protonation/deprotonation of a group with a pK(A) of 5.6. A model is suggested whereby the approach to equilibrium is catalyzed by the ribozyme catalyzing the ligation reaction in its deprotonated state (rate 1.05 min(-1)) and the cleavage reaction in its protonated state (rate 0.18 min(-1)). A756 is a candidate for the nucleobase undergoing protonation/deprotonation.     

羊松果体细胞原代培养及其生物学特性的研究

体外培养山羊及绵羊的松果体细胞,观察其增殖情况和功能状态的变化.结果显示:山羊、绵羊的松果体细胞体外形态及生长情况相似.细胞多呈圆形或多角形,细胞体积有增大趋势.采用MTT法检测细胞生长状态,发现细胞有明显的增殖现象,大约于11d达到高峰.用免疫组织化学对培养细胞进行染色,发现5-HT阳性细胞数量随细胞的增殖而增加.表明山羊和绵羊松果体细胞在体外均增殖旺盛,并能保持体内的分泌功能.     

峨眉双蝴蝶组织培养与快速繁殖(简报)

峨眉双蝴蝶植株带芽茎段的最佳芽诱导培养基为MS＋6-BA 1.5mg／L;在1／2MS＋IBA 1.0培养基上可诱导出根,生根率96％以上;生根苗经炼苗后移栽成活率在89％以上。     

新型声学造影剂在常规诊断超声频率下对在 体肾脏及离体培养细胞影响的研究

目的：评价新型超声造影剂在常规诊断超声频率下对组织细胞结构的影响。资料和方法：体外培养的人近曲小管上皮细胞分为造影剂无超声照射组,单纯超声照射组,MI 1．5,造影剂加超声照射组。MI 0．28,造影剂加超声照射组,MI 1．5。超声照射时间为10分钟。实验完后用2.5％的戊二醛固定4小时,送电镜室做扫描电镜。正常免肾经耳缘静脉按0．02ml／kg团注脂氟显（新桥医院超声科实验室自制）,用6MHz的超声频率照射,MI 0．28。照射10分钟。活体取肾皮质。放入3．0％的戊二醛溶液中固定,送电镜室做投射电镜。结果：离体培养的人近端小管上皮细胞单纯超声照射、单纯加造影剂、造影剂加超声照射MI 0．28和MI 1．5时扫描电镜观察细胞形态无改变,细胞表面未见异常。透射电镜观察免肾小囊腔和肾小管上皮细胞超微结构未见特异性政变。结论：新型脂质体声学造影剂在诊断剂量超声照射下不会对组织细胞结构产生影响。新型脂质体声学造影剂在诊断剂量下是安全的。     

Development of microsatellite markers for the tropical moss,Acanthorrhynchium papillatum

We isolated and characterized microsatellite loci for the palaeotropic moss, Acanthorrhynchium papillatum. Eight loci tested on 98 gametophytic samples generated four to 26 alleles per locus with genetic diversities ranging from 0.578 to 0.936. These microsatellite loci are now being used as genetic markers for studies on the effects of deforestation on moss populations in South‐East Asia.     

重组阿拉伯糖苷酶在毕赤酵母中的分泌表达及其活性分析

假密环菌是一种果树腐病菌,具有较强的分解代谢纤维素的能力。本文根据已克隆出的阿拉伯糖苷酶基因序列（Accession Number AJ620046）设计引物从假密环菌的mRNA中克隆出阿拉伯糖苷酶的ORF片段,构建重组质粒pPIC9-AF,与组氨酸标签融合,电转化毕赤酵母菌GS115并进行诱导表达。所得到的重组阿拉伯糖苷酶在30-35℃时有较高的酶活,最适反应活性pH值在6.0-8.0之间,而在pH4.0－8.0范围内酶活基本保持在80%以上,比大多已报道的阿拉伯糖苷酶最适pH范围宽。本研究工作对于高效表达重组阿拉伯糖苷酶以及对其进一步的酶学性质研究提供了一个良好的基础。