615小鼠血红蛋白α链的氨基酸组成及个别肽段的氨基酸序列

用CM-Cellulose-23柱层析分离纯化了615小鼠珠蛋白α链,测定其N端氨基酸残基为缬氨酸.615小鼠珠蛋白α链含有141个氨基酸残基,其中19个亮氨酸残基,10个组氨酸残基,9个缬氨酸残基,上述氨基酸残基的数目与文献中其亲本C₅₇BL不同.用胰蛋白酶水解615小鼠珠蛋白α链,发现有不溶性的‘核心’和可溶性的酶解片段.其中一个酶解肽段从N端数第8位氨基酸残基发生了突变,由亲本的缬氨酸变为亮氨酸.     

Ion Composition of the Chara Internode

Ion compositions of the cytoplasm and the vacuole of Chara australiswere analyzed according to Kishimoto and Tazawa (1964) and Kiyosawa(1979a). The ions in the cytoplasm and the vacuole analyzedwere K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl^–, NO₃^– and H₂PO₄^–.Assuming that the volume of the cytoplasm V_p is 10% of thatof the whole cell V, the concentrations of K⁺, Na⁺, Ca²⁺, Mg²⁺,Cl^–, NO₃^– and H₂PO₄^– in the cytoplasm averaged70, 15, 13, 4.6, 31, 2.2 and 16 mM, respectively. If the volumeof the cytoplasm was assumed to be 5% of that of the whole cell,their averaged concentrations were 139, 31, 25, 9.2, 62, 4.4and 33 mM, respectively. The averaged ion compositions of thecell sap were K⁺, 111; Na⁺, 47; Ca²⁺, 4.4; Mg²⁺, 8.9; Cl^–,91; NO^–₃, 3.3 and H₂PO₄^–, 6.0 mM. These values,taking the concentrations and the charges of the protein (Kiyosawa1979b) and amino acids (Sakano and Tazawa 1984) into accountand assuming the presence of some uni- or oligovalent anionsand/or small nonelectrolyte molecules, could explain fairlywell both the electroneutrality and the osmotic pressure ofthe cell, except when V_p/V = 5%. (Received May 18, 1987; Accepted September 29, 1987)     

Composition of the regulators of bacterial autolysis

This work was aimed at studying the composition of agents regulating bacterial autolysis and isolated from the lysate of Bacillus subtilis 402, B. subtilis R2 and Micrococcus lysodeikticus biomass by extraction with 5% TCA followed by precipitation from the extract with 5 volumes of isopropanol. Fractions activating bacterial autolysis and fractions inhibiting it were found in all of the preparations after separation on Acrylex P-60. Fractions with a molecular mass below 12,600 D activated the autolysis whereas fractions with a molecular mass above 18,400 D inhibited it. The activity of fractions inhibiting the autolysis decreased while that of fractions activating the autolysis increased in the regulating agents isolated from B. subtilis cultures with the aging of the latter. The capability of the fractions to activate the autolysis correlated with the content of amino groups and phosphate in them whereas the capacity to inhibit the autolysis correlated with the content of reducing sugars in the fractions. The preparation of the fraction which activated the autolysis from B. subtilis R2 contained 18 amino acids with the predominance of alanine, glutamic acid, lysine and phenylalanine. Apparently, the regulating properties of the preparations are created with the aid of teichoic acids as well as peptidoglycan and protein fragments associated with the acids.     

Enzyme Composition and the Taxonomy of Acanthamoeba

The enzyme activities of 37 representative strains of Acanthamoeba against 19 substrates have been examined. A total of 13 enzyme complements were identified, which could be arranged in six larger groups. There was good agreement between these groupings and the arrangement of the strains that was suggested by the electrophoresis patterns of their esterases and acid phosphatases. A nomericlature is described which provides an unequivocal numerical label for each enzyme complement.     

Structure and Composition of the Fusion Pore

Earlier studies using atomic force microscopy (AFM) demonstrated the presence of fusion pores at the cell plasma membrane in a number of live secretory cells, revealing their morphology and dynamics at nm resolution and in real time. Fusion pores were stable structures at the cell plasma membrane where secretory vesicles dock and fuse to release vesicular contents. In the present study, transmission electron microscopy confirms the presence of fusion pores and reveals their detailed structure and association with membrane-bound secretory vesicles in pancreatic acinar cells. Immunochemical studies demonstrated that t-SNAREs, NSF, actin, vimentin, α-fodrin and the calcium channels α1c and β3 are associated with the fusion complex. The localization and possible arrangement of SNAREs at the fusion pore are further demonstrated from combined AFM, immunoAFM, and electrophysiological measurements. These studies reveal the fusion pore or porosome to be a cup-shaped lipoprotein structure, the base of which has t-SNAREs and allows for docking and release of secretory products from membrane-bound vesicles.     

Composition of the bacterial flora in tonsilloliths

Tonsilloliths are a potential cause of oral malodor. In this study, microbial profiles and composition of tonsilloliths were determined using culture-independent molecular methods and scanning electron microscopy. 16S ribosomal RNA bacterial genes (16S rDNAs) isolated from tonsilloliths of 6 individuals were amplified by PCR and cloned into Escherichia coli. Partial 16S rDNA sequences of approximately 600 bases of cloned inserts were used to determine species identity by comparison with sequences of known species. Characteristics of bacteria on the surface and inside the tonsillolith were analyzed using scanning electron microscopy. Anaerobic bacteria detected in tonsilloliths belonged to the genera Eubacterium, Fusobacterium, Megasphaera, Porphyromonas, Prevotella, Selenomonas and Tannerella, all of which appear to be associated with production of volatile sulfur compounds. Electron microscopy revealed cocci and rods on the surface and rods predominating inside the tonsilloliths. These results support the tonsillolith as an origin of oral malodor.     

Composition of the synaptic PSD-95 complex

Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein interaction domains, forms the backbone of an extensive postsynaptic protein complex that organizes receptors and signal transduction molecules at the synaptic contact zone. Large, detergent-insoluble PSD-95-based postsynaptic complexes can be affinity-purified from conventional PSD fractions using magnetic beads coated with a PSD-95 antibody. In the present study purified PSD-95 complexes were analyzed by LC/MS/MS. A semiquantitative measure of the relative abundances of proteins in the purified PSD-95 complexes and the parent PSD fraction was estimated based on the cumulative ion current intensities of corresponding peptides. The affinity-purified preparation was largely depleted of presynaptic proteins, spectrin, intermediate filaments, and other contaminants prominent in the parent PSD fraction. We identified 525 of the proteins previously reported in parent PSD fractions, but only 288 of these were detected after affinity purification. We discuss 26 proteins that are major components in the PSD-95 complex based upon abundance ranking and affinity co-purification with PSD-95. This subset represents a minimal list of constituent proteins of the PSD-95 complex and includes, in addition to the specialized scaffolds and N-methyl-d-aspartate (NMDA) receptors, an abundance of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, small G-protein regulators, cell adhesion molecules, and hypothetical proteins. The identification of two Arf regulators, BRAG1 and BRAG2b, as co-purifying components of the complex implies pivotal functions in spine plasticity such as the reorganization of the actin cytoskeleton and insertion and retrieval of proteins to and from the plasma membrane. Another co-purifying protein (Q8BZM2) with two sterile alpha motif domains may represent a novel structural core element of the PSD.     

台湾海峡鱼类组成及其生态区系

本文依据台湾海峡鱼类物种的相关历史调查资料和文献, 分析了台湾海峡鱼类物种组成及其生态类型和区系特征, 探讨全球变化背景下台湾海峡鱼类物种组成变化。结果显示, 台湾海峡共有鱼类1,697种, 分隶40目206科740属, 其中, 目级分类阶元种类数最多的为鲈形目, 科级分类阶元种类数最多的为鰕虎科; 从适温性上看, 暖水性鱼类最多, 有1,560种, 其次为暖温性鱼类(128种)和冷温性鱼类(9种); 栖息地生态类型则以大陆架砂泥质底层鱼类和岩礁性鱼类种类数最多, 各有596种, 其后依次是大陆架近底层鱼类(249种)、大陆架中上层鱼类(158种)和大洋性鱼类(98种), 洄游性鱼类181种, 经济性鱼类735种; 海区间鱼类种类数对比显示, 台湾海峡鱼类与南海鱼类共有种最多, 共有种比例高达91.9%, 其次为东海(69.3%)和黄海(19.4%), 多为印度—西太平洋海区分布种, 仅288种广泛分布于中国各海区。由此, 台湾海峡鱼类区系特征兼有热带和亚热带海区鱼类区系特点, 属于印度—西太平洋暖水区系中—日亚区和印度—马来亚区的过渡海区, 其分界区域在台湾浅滩东部外缘至澎湖列岛偏北海域。     

大熊猫乳汁蛋白组成

测定了2只大熊猫（ailuropoda melanoleuca)乳汁中蛋白含量,乳糖含量,乳蛋白组成,并与成都麻羊（Capra hircus)初乳和中国荷斯坦牛（Bos taurus)乳进行了比较,大熊猫乳蛋白含量平均为41．52g/L,与中国荷斯坦牛乳接近;乳糖平均含量为15．41g/L,极显著低于牛乳和成都麻羊初乳,乳蛋白SDS－PAGE分析表明,大熊猫乳中酪蛋白（CN）含量明显低于羊乳和牛乳;乳中存在3条蛋白含量的区带,而在成都麻羊和中国荷斯坦牛乳电泳图谱的相应位置未见明显的区带,乳中上皮粘蛋白MUC1仅存在1条分子量约为196kDa的区带,未发现多态现象。