大豆抗冷性的生理生化研究及其指标筛选

本文研究了10个大豆品种在吸胀期对冷害的敏感性的差异。结果表明： （1）依据对低温反应的差异，各品种可归为三种类型：a）冷敏感型，低温处理使其各种萌发指标大幅度下降;b）抗冷型，低温处理使其各种萌发指标下降很小;c）中抗型，介于两者之间。 （2）低温导致的冷敏感品种的ATP含量下降幅度大于抗冷型的。 （3）抗冷品种脱氢酶活性高，且低温导致的下降幅度小;而冷敏感品种则相反。 （4）抗冷性越强，SOD活性越高，MDA含量越低，且低温导致的MDA含量的升高也越小。 （5）除个别品种外，低温导致的敏感品种的电导率升高大于抗冷型的。 （6）低温处理下，抗性品种的胚根细胞仍具有较高的ATPase活性，含有大量液泡和内质网;而冷敏感品种不仅ATPase活性低，且只有蛋白体和拟脂体，未见到液泡和内质网。 依据以上结果，提出了大豆吸胀冷害的可能机制：低温下质膜修复与重建、ATP迅速产生及一些酶的活化的受阻可能是大豆吸胀冷害的原初反应，由此导致一系列生理、生化紊乱，以致于萌发缓慢，活力降低。 我们建议萌发生理测定、ATP含量测定及电导实验可用做大豆抗冷性的评价。

非晶状体βγ-晶状体蛋白与三叶因子蛋白复合物的细胞核转运及其选择性杀伤肿瘤细胞机制的研究

非晶状体βγ晶状体蛋白与三叶因子蛋白复合物(βγ-CAT)是从大蹼铃蟾(Bombina maxima)皮肤分泌物中分离的分子量为72 kDa的天然蛋白复合物.本研究通过激光共聚焦显微镜和Westem blot分析βγ-CAT在人脐静脉内皮细胞(HUVEC)中的细胞核转运机制,以及βγ-CAT对多株肿瘤细胞(HCT116,HT29,A375,Hela,THP-1等)的细胞毒效应.结果表明:βγ-CAT的α亚基中含有典型的GTP/ATPase的保守结构模体Walker A和Walker B,体外检测到βγ-CAT具有GTP/ATP水解酶和GTP/ATP结合活性.在细胞核转运过程中,βγ-CAT的α亚基和β亚基参与形成约150kDa含有泛素化修饰信号的大分子复合物,且泛素化修饰信号和βγ-CAT的α亚基和β亚基共定位于细胞内和融合于细胞核区域的转运囊泡小体中.βγ-CAT能够选择性的杀伤肿瘤细胞,诱导肿瘤细胞脱落和发生凋亡.上述结果为进一步深入研究阡βγ-CAT的细胞核转运和调节细胞功能的分子作用机制提供思路和线索.

Comparison of physicochemical properties of muscle proteins in cultured and wild prawns (Penaeus (Fenneropenaeus) orientalis Kishinouye, 1918)

Protein physicochemical properties in cultured and wild prawns (Penaeus (F.) orientalis Kishinouye, 1918) were studied and compared. Protein fractions were separated into water-soluble, salt-soluble, alkali-soluble, and stroma. The results showed that salt- and alkali-soluble proteins were slightly higher in wild prawns and water-soluble proteins were higher in cultured prawns. There were only slight differences in Ca2+-ATPase, MG2+-ATPase, and ATP sensitivities. The textural values of wild prawns were significantly higher than the cultured ones.

Suitability of sodium lactate as cryoprotectant and its effect on gel forming ability and protein denaturation of croaker fish surimi during frozen storage

The effect of sodium lactate is compared with sucrose + sorbitol + sodium tri-poly phosphate as cryoprotectant on gel forming ability & protein denaturation of croaker surimi during frozen storage at -20±2°C for 90 days was evaluated. The quality of Croaker surimi with 6% (w/v) sodium lactate was examined in terms of biochemical parameters of muscle protein, thaw drip, gel strength and calcium ATPase activity :.omparing with those of surimi added with sucrose/sorbitol & without additive as control. Both the cryoprotectants minimized the negative effects of frozen storage on physico-chemical traits of myofibrillar proteins which was evident from the biochemical and sensory parameters. The residual Ca2+ ATPase activity and gel strength of surimi with sodium lactate were higher than those of control throughout 90 days of storage. Ca2+ A TPase activity and gel strength found a high positive correlation. From the results, it was found that sodium lactate was equally effective in preservation of croaker muscle protein native structure during frozen storage as the sucrose/ sorbitol and also less sweet without any risk of maillard browning.

大蹼铃蟾非晶状体βγ-晶状体蛋白与三叶因子蛋白复合物和基因及制法及用途

本发明涉及一种大蹼铃蟾非晶状体βγ-晶状体蛋白与三叶因子蛋白复合物和基因及制法及用途。其天然表观分子量为72kDa，由α亚基和β亚基按αβ2的分子形式以非共价键连接而成，为一类新的ATPase和GTPase酶，具有多种细胞生物活性，在体外纳摩尔水平能够杀死多种肿瘤细胞、抑制肿瘤细胞生长和诱导肿瘤细胞脱落和凋亡。在皮摩尔水平具有促进创伤修复的活性。在细胞外经单泛素化修饰，能够直接转运到细胞核中进行基因表达的调控从而调节细胞状态，包括细胞迁移、脱落、生长。本发明的蛋白复合物提供了非晶状体βγ-晶状体蛋白全新的细胞生物学功能及其能够与三叶因子蛋白协同作用的机制，可应用于生物医学试剂制备和抗肿瘤以及促进创伤修复制药

Improved handling and preservation of freshwater giant prawn, Macrobrachium rosenbergii for producing safe and wholesome products

Studies were undertaken to evaluate the quality changes in freshwater giant prawn, Macrobrachium rosenbergii during various storage conditions of handling and preservation and producing safe and quality products. The samples kept in ice immediately after catch with head-on and head-less condition were found to be acceptable for 6 days and 7 days, respectively. Delaying of icing considerably shortened the shelf-life. The pH value increased from 6.36 to 8.0 after 10 days in ice. The initial average TVB-N value of sample increased from below 10 mg/100 g to 25 mg/100 g with the lapse of storage period. The Ca++ ATPase activity in presence of 0.1M KCl slightly decreased at the end of 10 days of ice storage. Immediately after harvest, initial aerobic plate count (APC) was 2.88x10^6 CFU/g which gradually increased to 1.12x10^8 CFU/g after 6 days in ice storage and showed early signs of spoilage. Initial bacterial genera in the prawn iced at 0 hours were comprised of Coryneform (22.21 %), Bacillus (7.40%), Micrococcus (11.11 %), Achromobacter (48.14%), Flavobacterium/Cytophaga (7.40%), Pseudomonas (3.70%) and Aeromonas (3.70%). During ice storage Coryneforms and Bacillus were always dominating along with less prominent ones - Micrococcus, Achromobacter and Flavobacterium. Studies were conducted on the stability of myofibrillar protein of M. rosenbergii under different storage and pH conditions. The influence of a wide range of pH on the remaining Ca++ ATPase activity of M. rosenbergii muscle myofibrils after storage at -20°C for 2 days, at 0°C for 2 days and at 35°C for 30 minutes demonstrated that ATPase activities were lower in acidic and alkaline pH regions and the activity remained relatively high. Mg++ ATPase activities both in presence and absence of Ca++ remained high at neutral pH compared to those of acidic and alkaline region. The solubility of myofibrillar protein decreased gradually both in acidic and alkaline pH regions. The study also examined the bacteriological quality of freshly harvested M. rosenbergii, pond sediment and pond water from four commercial freshwater prawn farms at Fulpur and Tarakanda upazilas in the district of Mymensingh. The study included aerobic plate count (APC), total coliform count, detection, isolation and identification of suspected public health hazard bacteria and their seasonal variation, salt tolerance test, antibiotic sensitivity test of the isolates and washing effect of chlorinated water on the bacterial load in the prawn samples. APC in sediment soil and water of the farm and gill and hepatopancreas of freshly harvested prawns varied considerably among the farms and between summer and winter season. The range of coliform count in water, gill and hepatopancreas ranged between 6 - 2.8x10^2 CFU/ml, 1.2x10^2 - 3.32x10^2 CFU/g and 1.43x10^2 - 3.89 x10^3 CFU/g, respectively. No coliform was detected in pond sediment sample. Suspected health hazard bacteria isolated and identified from pond sediment, water, gill and hepatopancreas included Streptococcus, Bacillus, Escherichia coli, Klebsialla, Salmonella, Staphylococcus, Pseudomonas and Aeromonas. Bacillus, Salmonella and Staphyloccus [sic], and were found to be highly salt tolerant and capable of growing at 10% NaCl. The antibiotic discs with different concentration of antibiotics were used for the sensitivity test. The organisms were found to be most sensitive against Tetracyclin and Gentamycin.

Technological aspects of preservation and processing of edible shell fishes III. Factors influencing the keeping quality of crab (Scylla serrata) during freezing and frozen storage

The possible factors leading to the loss of flavour and general quality of crab during freezing and frozen storage have been studied. The preprocess ice storage condition of the raw material was found to be one such important factor while the fresh frozen crab meat remained in good organoleptic condition for about 51 weeks at -23°C, the 7 days iced material held frozen was found to have a shelf life of about 21 weeks. The fall in myofibrillar protein noted during frozen storage together with the loss of myosin ATPase activity correlated well with the loss of organoleptic qualities.

Denaturation of Labeo rohita (Rohu) actomyosin on frozen storage: preventive effect of carbohydrates

The preventive effect of sucrose and glucose on the denaturation of frozen rohu actomyosin at -20°C for 7 weeks was examined using an in vitro test model. The rate of denaturation was followed by estimating percentage salt extractability, Ca¹²+ ATPase activity and the clearing response test. Sucrose and glucose showed cryoprotective action for all concentration of actomyosin. Higher actomyosin concentration was preserved better than lower concentration. Post-rigor actomyosin was preserved to a greater extent than pre-rigor actomyosin. Correlation between percentage salt extractability and enzyme activity could not be observed in all samples of frozen actomyosin studied.

Comparison of physicochemical properties of muscle proteins in cultured and wild prawns (Penaeus (Fenneropenaeus) orientalis Kishinouye, 1918)

Protein physicochemical properties in cultured and wild prawns (Penaeus (F.) orientalis Kishinouye, 1918) were studied and compared. Protein fractions were separated into water-soluble, salt-soluble, alkali-soluble, and stroma. The results showed that salt- and alkali-soluble proteins were slightly higher in wild prawns and water-soluble proteins were higher in cultured prawns. There were only slight differences in Ca super(2+)-ATPase, MG super(2+)-ATPase, and ATP sensitivities. The textural values of wild prawns were significantly higher than the cultured ones.

Identification, characteristic and phylogenetic analysis of type II DNA topoisomerase gene in Giardia lamblia

The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene, GlTop 2 was identified. It is a single copy gene with a 4476 by long ORF without intron. The deduced amino acid sequence shows strong homology to eukaryotic DNA Top 2. However, some distortions were found, such as six insertions in the ATPase domain and the central domain, a similar to 100 as longer central domain; a similar to 200 as shorter C-terminal domain containing rich charged residues. These features revealed by comparing with Top 2 of the host, human, might be helpful in exploiting drug selectivity for antigiardial therapy. Phylogenetic analysis of eukaryotic enzymes showed that kinetoplastids, plants, fungi, and animals were monophyletic groups, and the animal and fungi lineages shared a more recent common ancestor than either did with the plant lineage; microsporidia grouped with fungi. However, unlike many previous phylogenetic analyses, the "amitochondriate" G. lamblia was not the earliest branch but diverged after mitochondriate kinetoplastids in our trees. Both the finding of typical eukaryotic type IIA topoisomerase and the phylogenetic analysis suggest G. lamblia is not possibly as primitive as was regarded before and might diverge after the acquisition of mitochondria. This is consistent with the recent discovery of mitochondrial remnant organelles in G. lamblia.

Effects of atrazine herbicide on physiological, biochemical and histological biomarkers of developmental stages of larvae and fry in Caspian kutum, Rutilus frisii kutum

To investigation of the toxic effects of atrazine on newly hatched larvae and releasing age fry of the Caspian Kutum, Rutilus frisii kutum, the 96h LC50 was determined as 18.53 ppm and 24.95 ppm, respectively. Newly hatched larvae were exposed to three sublethal concentrations of atrazine (1/2LC50, 1/4LC50 and 1/8LC50) for 7 days. Different histopathological alterations were observed in fins and integument, gills, Kidney, digestive system, liver and the brain of the exposed larvae. Fry’s were exposed to one sublethal concentration of atrazine (1/2LC50) for four days, and like the larvae’s, many histopathological alterations were observed in fins and integument, gills, Kidney, digestive system, liver and the brain of the exposed fry’s, too. Also, measurements of the body ions: Na+, K+, Ca2+, Mg2+ and Cl- in atrazine exposed larvae and fry’s compare to control groups showed that atrazine is changed the body ions composition. No significant differences were found in length growth rate, weight growth rate and the condition factor of the atrazine exposed larvae and fry. Immunohistochemical localization of the Na+, K+-ATPase in integumentary and gill ionocytes, showed no differences in dispersion pattern of the ionocytes in atrazine exposed larvae and fry, compare to control group. Measuring the dimensions of the ionocytes and counting the ionocytes showed that atrazine is affecting on ionocytes by mild increasing in size and mild decreasing in number. Ultrastructural studies, using SEM and TEM, showed that atrazine have significant effects on cellular and subcellular properties. It caused necrosis in surface of the pavement cells in branchial epithelium, necrosis in endoplasmic reticulum of the ionocytes and changed the shape of the mitochondria in these cells. Results showed that sublethal concentrations of atrazine were very toxic to larvae and fry of the Rutilus frisii kutum, and at these levels can made some serious histopathological alterations in their tissues. Related to the severe histopathological alterations in osmoregulatory organs, like gill, kidney and digestive system, and the alterations in the body ion composition, it could be concluded that atrazine could interfere with the osmoregulation process of the Rutilus frisii kutum at the early stages of the life history.

Theoretical studies on conformation comparison of braid-like and triplex DNA

Based on the experimental data of scanning tunneling microscopy (STM), models of three-stranded braid-like DNAs composed by three kinds of base triplets AAA, TAT and GCA were constructed. We investigated the braid-like DNAs and their comparative tripler DNAs using a molecular mechanics method. The three strands of braid-like DNAs are proven equivalent, while those of tripler DNAs are not. The conformational energies for braid-like DNAs were found to be higher than that for tripler DNAs. Each period in one strand of braid-like DNA has 18 nucleotides, half of which are right-handed, while the other half are left-handed. Additional discussions concerning sugar puckering modes and the H-bonds are also included. (C) 1999 Elsevier Science B.V. All rights reserved.

Influence of specific HSP70 domains on fibril formation of the yeast prion protein Ure2.

Ure2p is the protein determinant of the Saccharomyces cerevisiae prion state [URE3]. Constitutive overexpression of the HSP70 family member SSA1 cures cells of [URE3]. Here, we show that Ssa1p increases the lag time of Ure2p fibril formation in vitro in the presence or absence of nucleotide. The presence of the HSP40 co-chaperone Ydj1p has an additive effect on the inhibition of Ure2p fibril formation, whereas the Ydj1p H34Q mutant shows reduced inhibition alone and in combination with Ssa1p. In order to investigate the structural basis of these effects, we constructed and tested an Ssa1p mutant lacking the ATPase domain, as well as a series of C-terminal truncation mutants. The results indicate that Ssa1p can bind to Ure2p and delay fibril formation even in the absence of the ATPase domain, but interaction of Ure2p with the substrate-binding domain is strongly influenced by the C-terminal lid region. Dynamic light scattering, quartz crystal microbalance assays, pull-down assays and kinetic analysis indicate that Ssa1p interacts with both native Ure2p and fibril seeds, and reduces the rate of Ure2p fibril elongation in a concentration-dependent manner. These results provide new insights into the structural and mechanistic basis for inhibition of Ure2p fibril formation by Ssa1p and Ydj1p.

苯并(a)芘致毒的鱼的分子生态毒理学指标研究

通过测定典型的多环芳烃类物质苯并（a）芘（BaP）致毒后鱼体内几种重要分子生态毒理学指标的变化，来反映苯并（a）芘致毒对鱼体的影响．结果表明，肝脏ATPase活性降低，GST活性升高，DNA加合物相对标记水平（RAL）也增大，而EROD活性没有明显改变．这说明苯并（a）芘致毒对鱼体正常生命活动产生了重大影响，并具有潜在的致癌性．

盐生杜氏藻细胞对回转器模拟微重力刺激的反应

通过回转器模拟微重力刺激实验 ,以盐生杜氏藻为试验材料 ,发现在微重力刺激下 ,盐生杜氏藻细胞及其生理生化特性发生了一系列的变化 .具体表现为甘油含量增加 ;H+分泌速率加快 ;膜磷脂与膜蛋白比率下降 ;质膜 (PM )H+ ATPase活性升高等 .这些变化表明 ,微重力环境对藻类来说是一个耗能胁迫环境 .微重力对藻细胞代谢特性的影响可能是通过次级的水分胁迫而产生的