Origin and evolution of new exons in the rodent zinc finger protein 39 gene

The origin of new structures and functions is an important process in evolution. In the past decades, we have obtained some preliminary knowledge of the origin and evolution of new genes. However, as the basic unit of genes, the origin and evolution of exons remain unclear. Because young exons retain the footprints of origination, they can be good materials for studying origin and evolution of new exons. In this paper, we report two young exons in a zinc finger protein gene of rodents. Since they are unique sequences in mouse and rat genome and no homologous sequences were found in the orthologous genes of human and pig, the young exons might originate after the divergence of primates and rodents through exonization of intronic sequences. Strong positive selection was detected in the new exons between mouse and rat, suggesting that these exons have undergone significant functional divergence after the separation of the two species. On the other hand, population genetics data of mouse demonstrate that the new exons have been subject to functional constraint, indicating an important function of the new exons in mouse. Functional analyses suggest that these new exons encode a nuclear localization signal peptide, which may mediate new ways of nuclear protein transport. To our knowledge, this is the first example of the origin and evolution of young exons.     

The scorpine family of defensins: gene structure,alternative polyadenylation and fold recognition

Small cationic antimicrobial peptides (SCAMPs) as effectors of animal innate immunity provide the first defense against infectious pathogens. This class of molecules exists widely in invertebrate hemolymph and vertebrate skin secretion, but animal venoms are emerging as a new rich resource. Scorpine is a unique scorpion venom defensin peptide that has an extended amino-terminal sequence similar to cecropins. From the African scorpion Opistophthalmus carinatus venom gland, we isolated and identified several cDNAs encoding four new homologs of scorpine (named opiscorpines 1–4). Importantly, we show for the first time the existence of multiple opiscorpine mRNAs with variable 3 untranslated regions (UTRs) in the venom gland, which may be generated by alternative usage of polyadenylation signals. The complete opiscorpine gene structure including its promoter region is determined by genomic DNA amplification. Two large introns were found to be located within the 5 UTR and at the boundary of the mature peptide-coding region. Such a gene structure is distinct, when compared with other scorpion venom peptide genes. However, a comparative promoter analysis revealed that both opiscorpine and scorpion venom neurotoxins share a similar promoter organization. Sequence analysis and structural modeling allow us to group the scorpines and scorpion long-chain K-channel toxins together into one family that shares a similar fold with two distinct domains. The N-terminal cecropin-like domain displaying a clear antimicrobial activity implies that the scorpine family represents a group of real naturally occurring hybrids. Based on the phylogenetic analysis, a possible cooperative interaction between the N and C domains is elucidated, which provides an evolutionary basis for the design of a new class of anti-infectious drugs.Received 5 April 2004; accepted 17 May 2004     

丹参有效成分的提取及抗氧化研究

对丹麦脂溶性成分的抗氧化能力做了比较全面的研究，同时对其提取方法做了比较深入的探索。结果发明，丹参的脂溶性成分抗氧化能力很强，当０．０８％的ＳＭＥＣ和０．０４％的ＴＢＨＱ一起使用时，ＥＰＡ和ＤＨＡ的氧化稳定性增加了３６倍，随着温度的降低，ＳＭＥＣ对ＥＰＡ和ＤＨＡ的抗氧化效果明显增加；１１０℃时，ＳＭＥＣ对猪油仍然有很强的抗氧化作用，并且发现野生丹参ＳＭＥＣ的含量是栽培丹参的５倍。     

脑钠素的基因工程研究

脑钠素是利钠多肽家族成员之一 ,存在于人体的多种器官组织中 .脑钠素具有很强的利钠利尿、舒张血管和降低血压等生理功能 ,而脑钠素的改变与高血压、心脑血管病和肾病等许多疾病有关 .脑钠素具有潜在的药用开发价值和良好的应用前景 ,其开发通常采用基因工程手段 ,但至今尚未成功 .本文综合评述了脑钠素基因工程研究的历史与现状 ,全面分析了所存在的问题 ,并提出了相应的解决问题的方法 .     

没食子酸丙酯合成工艺研究

报道没食子酸和正丙醇在硫酸等酸性催化剂存在下，采用外脱水和水溶剂重结晶法制造食品级没食子酸丙酯。该方法与传统硫酸法相比，具有简便、安全、收率高和产品质量稳定等优点，适于工业生产采用。     

家蚕蛹抗菌肽β组分水溶液的激光喇曼光谱

报道了家蚕蛹抗菌肽β组分水溶液的喇曼光谱，结果表明，抗菌肽β组分的主链结构主要由β－螺旋及小量的β－折叠和β－回转构成，并提示抗菌肽β－组分可能为糖肽。     

Fungitoxicity ofm-fluorophenylalanine-containing peptides towardsPythium ultimum

Summary The tripeptide L-m-fluorophenylalanyl-L-alanyl-L-alanine was much more fungitoxic towardsPythium ultimum than the dipeptide L-m-fluorophenylalanyl-L-alanine orm-fluorophenylalanine. The fungitoxicity of the tripeptide was reduced by L-alanyl peptides and phenylalanine, but not by other amino acids. In contrast, the fungitoxicity ofm-fluorophenylalanine was unaffected by peptides, and was antagonized by several amino acids. These results suggest the effective delivery ofm-fluorophenylalanine into the cell by a tripeptide carrier.     

抗生素药物环丙沙星对剑尾鱼的毒性效应

测试了抗生素药物盐酸环丙沙星(Ciprofloxacin hydrochloride,CPFX)对剑尾鱼(Xiphophorus helleri)的急性毒性及其Ⅰ相、Ⅱ相代谢酶活性的影响。结果表明CPFX对剑尾鱼无急性毒性;CPFX对剑尾鱼肝脏还原型谷光苷肽(GSH)、谷光苷肽硫转酶(GST)和7-乙氧基异吩恶唑酮-脱乙基酶(EROD)都存在诱导作用;雌雄个体在EROD的诱导响应有一定的差异性,其中雌性个体EROD对CPFX暴露响应变化较大。     

四溴双酚A对鲫鱼血清抗氧化系统的影响

研究了幼龄鲫鱼(Carassius auratus)体外暴露于四溴双酚A(TBBPA)后,血清抗氧化系统中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)及过氧化氢酶(CAT)活性和还原型谷胱甘肽(GSH)含量分别随暴露剂量和时间的变化.在整个试验剂量范围内,GSH含量被显著抑制;GSH-Px在中低浓度下被显著诱导,高浓度时活性变化不大;SOD、CAT活性在高浓度暴露时显著升高.0.1 mg/L动态暴露中,GSH含量在整个过程中都被抑制,SOD呈先抑制后诱导,GSH-Px在暴露初期和中期被诱导CAT活性则在暴露后期被显著诱导.试验表明在鱼体受到不同程度的氧化胁迫时,可能会倾向于选择不同的应激补偿机制来消除胁迫;GSH对TBBPA十分敏感,可以考虑作为水环境中TBBPA污染的生物监测指标.