力竭性运动后大鼠血清CK、CK-MB活性和心肌组织形态学的动态改变

目的：探讨一次和反复力竭性运动后不同时相大鼠血清肌酸激酶（CK）、肌酸激酶同工酶（CK-MB）与心肌损伤的变化规律。方法：通过力竭性游泳制备运动性心肌损伤模型,分别于运动后即刻和3 h6、h、12 h2、4 h4、8 h、96 h检测血清CK、CK-MB活性,并观察心肌组织形态学的动态变化。结果：大鼠一次力竭运动后0~12 h,CK和CK-MB活性明显增加,6 h达高峰;心肌炎细胞浸润灶逐渐增多,胞质嗜酸性增强,损伤高峰在12 h左右。反复力竭运动后0~12 h和48 h9、6 h CK和CK-MB活性皆明显增加,分别于运动后即刻和96 h达高峰;心肌细胞均有不同程度的损伤,48 h最严重。结论：过度运动和/或力竭性运动皆引起运动性心肌损伤,同时存在延迟性心肌损伤。     

miRNA response to DNA damage

Faithful transmission of genetic material in eukaryotic cells requires not only accurate DNA replication and chromosome distribution but also the ability to sense and repair spontaneous and induced DNA damage. To maintain genomic integrity, cells undergo a DNA damage response using a complex network of signaling pathways composed of coordinate sensors, transducers and effectors in cell cycle arrest, apoptosis and DNA repair. Emerging evidence has suggested that miRNAs play a crucial role in regulation of DNA damage response. In this review, we discuss the recent findings on how miRNAs interact with the canonical DNA damage response and how miRNA expression is regulated after DNA damage.     

Intracellular expression of Vitreoscilla hemoglobin improves S-adenosylmethionine production in a recombinant Pichia pastoris

To develop an efficient way to produce S-adenosylmethionine (SAM), methionine adenosyltransferase gene (mat) from Streptomyces spectabilis and Vitreoscilla hemoglobin gene (vgb) were coexpressed intracellularly in Pichia pastoris, both under control of methanol-inducible promoter. Expression of mat in P. pastoris resulted in about 27 times higher specific activity of methionine adenosyltransferase (SMAT) and about 19 times higher SAM production relative to their respective control, suggesting that overexpression of mat could be used as an efficient method for constructing SAM-accumulating strain. Under induction concentration of 0.8 and 2.4% methanol, coexpression of vgb improved, though to different extent, cell growth, SAM production, and respiratory rate. However, the effects of VHb on SAM content (specific yield of SAM production) and SMAT seemed to be methanol concentration-dependent. When cells were induced with 0.8% methanol, no significant effects of VHb expression on SAM content and specific SMAT could be detected. When the cells were induced with 2.4% methanol, vgb expression increased SAM content significantly and depressed SMAT remarkably. We suggested that under our experimental scheme, the presence of VHb might improve ATP synthesis rate and thus improve cell growth and SAM production in the recombinant P. pastoris.     

Effects of the novel allelochemical ethyl 2-methylacetoacetate from the reed (<Emphasis Type="Italic">Phragmitis australis</Emphasis> Trin) on the growth of several common species of green algae

Bioassays were performed to investigate the effects of the novel allelochemical, ethyl 2-methylacetoacetate (EMA), isolated from the reed (Phragmitis australis) on the growth of three common species of algae; Scenedesmus obliquus, Selenastrum capricornutum and Chlamydomonas reinhardtii. The results demonstrated that EMA has three quite different types of effect on these three species of algae. The growth of S. capricornutum was significantly inhibited by EMA during the whole cultivation period. The EC₅₀ values of EMA on S. capricornutum was 0.6 mg L⁻¹(7 days). However, the inhibitory effect of EMA on S. obliquus was apparent during the first 4 days of batch cultivation and then the inhibitory effect disappeared, and a stimulating effect was observed instead. The EC₅₀ value of EMA on S. obliquus was 0.43 mg L⁻¹(4 days). In addition, following the addition of EMA, the cells of S. obliquus and S. capricornutum became significantly larger than the normal untreated one and the algal cells changed morphologically. The microstructure of the algal cells was disrupted by the addition of EMA. There was no significant inhibition of the growth of C. reinhardtii by EMA, but cell motility was affected.     

棉铃虫核型多角体病毒Hind III-K片段的核苷酸序列及其分析

测定了棉铃虫（Ｈｅｌｉｃｏｖｅｒｐａａｒｍｉｇｅｒａ）核型多角体病毒（ＨａＳＮＰＶ）基因组ＤＮＡ的ＨｉｎｄＩＩＫ片段核苷酸序列。该片段全长３２５５ｂｐ,含可编码大于４０个氨基酸残基的多肽的开放阅读框（ＯＲＦ）１５个,包括多角体蛋白（ｐｈ）基因编码区３′端４８９ｂｐ和蛋白激酶ＨａｖＰＫ基因编码区８０１ｂｐ。在ｐｈ和ＨａｖＰＫ两基因之间鉴定出一个可编码４１２个氨基酸残基的ＯＲＦ１２３６,转录方向与ｐｈ和ＨａｖＰＫ基因相反。同源分析表明,ＯＲＦ１２３６与谷实夜蛾（Ｈｅｌｉｃｏｖｅｒｐａｚｅａ）核型多角体病毒（ＨｚＳＮＰＶ）的ＯＲＦ８推导的蛋白氨基酸序列有９５．９％同源性,与苜蓿丫纹夜蛾（Ａｕｔｏｇｒａｐｈａｃａｌｉｆｏｒｎｉａ）核型多角体病毒（ＡｃＭＮＰＶ）ＯＲＦ１６２９只有２４．８％同源性,但三者均含有二组由多个脯氨酸残基串联而成的特征基序。     

马桑菌株的生物学特性

对从湖北、四川、云南等地采集的尼泊尔马桑(Coriaria nepalensis Wall.)根瘤中分离的20株内生菌纯培养物所进行的研究表明,其形态均具有弗兰克氏菌属的特征。在粗细不一的分枝菌丝体上有泡囊和孢囊,有的还有串珠状结构的菌丝体。不同菌株在液体培养基上生长速度很不一致;菌丝体多呈絮状或颗粒状沉淀,个别还呈薄膜状沉淀;绝大多数菌株的菌丝体具有不同色调的色素;在S培养基中大多数都能产生可溶性色素。上述这些培养特征常因培养基成分和培养方式的不同而有差异。大多数菌株的胞壁组分属Ⅱ型,少数菌株为Ⅲ型;全细胞糖型变化很大,20个菌株可划分为6个糖型,而且绝大多数糖型与已知弗兰克氏菌有所不同。此外,有65％的菌株还具有明显的抗菌活性。     

胜红蓟化感物质之间相互作用的研究

 通过柱层析从胜红蓟挥发油中分离出早熟素Ⅰ、早熟素Ⅱ、子丁香烯、3,3-二甲基-5-特丁基茚酮、红没药烯、乙酸葑醇酯等6种主要化感物质(占挥发油总量的97％),并研究了这些化感物质在挥发、淋溶(饱和水溶液)和土壤降解途径下对萝卜,番茄和绿豆幼苗的化感作用。结果表明：早熟素Ⅰ、早熟素Ⅱ、3,3-二甲基-5-特丁基茚酮及子丁香烯(挥发途径)虽有较强的化感活性,但均弱于挥发油的化感活性,而子丁香烯(淋溶途径),红没药烯和乙酸葑醇酯则基本无化感活性。但是,早熟素n和无活性的三个化感物质结合,则表现出强烈的化感活性,说明胜红蓟各化感物质之间存在着明显的协同作用。     

The DEK protein--an abundant and ubiquitous constituent of mammalian chromatin

The protein DEK is an abundant and ubiquitous chromatin protein in multicellular organisms (not in yeast). It is expressed in more than a million copies/nucleus of rapidly proliferating mammalian cells. DEK has two DNA binding modules of which one includes a SAP box, a sequence motif that DEK shares with a number of other chromatin proteins. DEK has no apparent affinity to specific DNA sequences, but preferentially binds to superhelical and cruciform DNA, and induces positive supercoils into closed circular DNA. The available evidence strongly suggests that DEK could function as an architectural protein in chromatin comparable to the better known classic architectural chromatin proteins, the high-mobility group or HMG proteins.     

油桐尺蠖单粒包埋核型多角体病毒（BusuNPV）BamHI—H片段的序列分析

对油桐尺蠖单粒包埋核型多用体病毒（Buzurasuppressariasingle－nucleocapsidnucleopolyhedrovirus,BusuNPV）基因组中BamHI－H片段的序列进行分析,该片段全长2422bp,包括三个开放阅读框：p47基因（AcMNPVORF40的同源区）的5′端,完整的组织蛋白酶基因（cathepsin）（AcMNPVORF127的同源区）和p74基因（AcMNPVORF138的同源区）的3′端。序列比较分析表明,BusuNPV的这三个基因与其它杆状病毒的同源基因具有相同的结构保守区。BusuNPV基因组BamHI－H片段上这三个基因的排列顺序完全不同于AcMNPV相应基因的排列顺序。