植物遗传资源的评价、保持和利用

阐明了植物遗传资源的重要作用,认为植物遗传资源是人类赖以生存和发展的物质基础,是植物育种丰富的基因资源的重要保证;分析了植物遗传资源评价的重要性,指出对植物遗传资源的正确评价是科学利用的前提;介绍了植物遗传资源的原生境保持和非原生境保持2种重要方法;重点论述了作物的高产基因、抗性基因及抗旱基因与肥高效基因等植物遗传资源的挖掘与利用,为引起人们对植物遗传资源保持重要性的高度认识提供理论参考。     

Trace Elements in Fingernails of Healthy Chinese Centenarians

Trace element concentrations in body tissues of healthy centenarians have not been widely analyzed, yet they can be used as reference data leading to improved assessment of the aging process and monitoring of the micronutrient status of this age group. The present study sought to assess trace element concentrations and behaviors in the fingernails of healthy Chinese centenarians. The effects of gender on element concentrations, which also play an important role in determining the lifespan, were also investigated. Trace elements (Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Se, Sr, and Zn) in the fingernails of 78 healthy Chinese centenarians were determined by inductively coupled plasma mass spectrometry. The overall reference values obtained in milligram per kilogram are as follows: Ba, 5.10; Cd, 0.031; Co, 0.101; Cr, 0.82; Cu, 3.71; Fe, 154.35; Li, 0.31; Mn, 3.09; Mo, 0.040; Ni, 0.95; Pb, 1.86; Se, 0.44; Sr, 6.20; and Zn, 147.96. Data analysis showed that only Cr and Se concentrations show a normal distribution, and no significant difference between male and female groups was found for any element except Cr. Result also revealed that sufficient Se, Co, and Zn as well as lower or lack of exposure to Cr contribute positively to the lifespan of centenarians. The results suggest that regulating in vivo contents of trace elements, especially Se, Co, and Zn, is reasonable to intervene with geriatric diseases.     

An integrin from shrimp Litopenaeus vannamei mediated microbial agglutination and cell proliferation

Background

Integrins are a family of adhesion receptors which regulate cell proliferation, differentiation, leukocyte migration, and complement receptor-dependent phagocytosis. In invertebrates, as a cell adhesion receptor, β integrins play an important role for the balanced activation of immune defense responses especially during the encounter of infections. The present study attempts to characterize the immune functions of shrimp integrin (LvIntegrin) to have better understanding on the immune system and its regulation mechanisms in shrimps.

Methodology

A shrimp integrin was identified from the Pacific white shrimp Litopenaeus vannamei (designated as LvIntegrin). Its full-length cDNA was of 2621 bp with an open reading frame (ORF) of 2439 bp encoding a polypeptide of 812 amino acids. The mRNA expression of LvIntegrin was significantly up-regulated at 3, 6 and 12 h after Listonella anguillarum challenge. The cDNA fragment encoding β integrin domains (βA and hybrid domain) of LvIntegrin was recombined and expressed in Escherichia coli BL21(DE3)-pLysS. The recombinant protein (rLvIntegrin) could significantly agglutinate the tested microbe including E. coli JM109, L. anguillarum, Micrococcus luteus and Candida dattiladattila in the presence of divalent cations. Moreover, when NIH3T3 cells were cultured with rLvIntegrin, the proliferation rate increased significantly in a dose-dependent manner.

Conclusions

LvIntegrin, a shrimp β integrin was identified from L. vannamei, shared several highly conserved features. LvIntegrin exhibited broad-spectrum agglutination activity towards both bacteria and fungi and could improve the proliferation of NIH3T3 cells, indicating that LvIntegrin is involved in the immune response against microbe challenge and regulation of cell proliferation as a cell adhesion receptor in shrimp.     

两性霉素B脂质体、氟胞嘧啶和伊曲康唑联合治疗隐球菌性脑膜炎的临床回顾性研究

目的 观察两性霉素B脂质体、氟胞嘧啶和伊曲康唑联合治疗非AIDS、非器官移植隐球菌性脑膜炎患者的疗效和安全性,探讨非AIDS、非器官移植隐球菌性脑膜炎患者诱导治疗的新方案.方法 采用回顾性病例对照研究,18例非AIDS、非器官移植隐球菌性脑膜炎患者诱导期分别接受两性霉素B脂质体、氟胞嘧啶和伊曲康唑联合(研究组n=7)与两性霉素B、氟胞嘧啶和氟康唑联合治疗(对照组n=11).比较两组治疗方案在临床症状、体征变化、病死率、病原学转阴率、脑脊液改变等方面的差异及血常规、肝肾功能损害等不良反应发生情况.结果 治疗前研究组和对照组脑脊液新型隐球菌培养阳性分别为5例和8例(P =0.676),治疗1周后分别为5例和8例(P =0.676),治疗2周后分别为2例和4例(P =0.572),治疗3周后分别为0例和1例(P=0.611),治疗4周后,无死亡病例,两组脑脊液新型隐球菌培养均为阴性,脑脊液生化两组之间差异无统计学意义,对照组较研究组丙氨酸氨基转移酶(156.82±41.30 vs 97.00±22.02,P=0.003)、尿素氮(8.45±3.18 vs 5.54±1.28,P=0.020)升高更明显.结论 两性霉素B脂质体、氟胞嘧啶及伊曲康唑联合治疗非AIDS、非器官移植隐球菌性脑膜炎患者疗效确切,安全性较好,可以作为诱导期治疗的选择.     

白细胞介素-21与乙型肝炎病毒前S2S抗原融合蛋白在293T细胞中的表达

目的:构建白细胞介素-21(interleukin-21,IL-21)和乙型肝炎病毒前S2S抗原(S2S)的融合表达质粒,并研究其在293T细胞中的表达。方法:采用PCR方法扩增IL-21和HBV前S2S基因片段,分别克隆入pcDNA3真核表达质粒,用分子克隆方法构建融合表达质粒,并以脂质体2000转染293T细胞,分别应用ELISA法和Western Blot法检测细胞上清及细胞中IL-21和HBsAg的表达水平。结果:经酶切鉴定及DNA序列证实重组质粒内插入片段序列正确,三种重组质粒分别命名为pcDNA-IL-21、pcDNA-S2S和pcDNA-IL-21-S2S,并且重组质粒能在293T细胞内表达并分泌相关蛋白。结论:成功构建IL-21和乙型肝炎病毒前S2S抗原的融合表达质粒,重组质粒能在真核细胞内表达。     

枯草杆菌脂肪水解酶LipA和LipB

源自枯草杆菌的分泌型脂肪水解酶LipA及LipB已经被克隆、表达并表征. 它们的分子结构特点、催化机理也已经被深入研究. 枯草杆菌脂肪水解酶因为具有较好的食品工业及化学工业等方面的应用潜力,已经吸引了越来越多的关注. 通过定向进化及高通量筛选的方法对酶分子进行改造,提高其热稳定性及立体选择性是近年的研究热点. 结合国外及本研究组的工作,本文对LipA和LipB的生化性质、结构特点以及采用基因工程突变的方法进行分子改造等方面的研究进展做一简要综述. 另外,对其中一些研究论文做了简要的评价,并提出对未来工作的展望.     

Diverse Tetracycline Resistant Bacteria and Resistance Genes from Coastal Waters of Jiaozhou Bay

Environmental microbiology investigation was carried out in Jiaozhou Bay to determine the source and distribution of tetracycline-resistant bacteria and their resistance mechanisms. At least 25 species or the equivalent molecular phylogenetic taxa in 16 genera of resistant bacteria could be identified based on 16S ribosomal deoxyribonucleic acid sequence analysis. Enterobacteriaceae, Pseudomonadaceae, and Vibrionaceae constituted the majority of the typical resistant isolates. Indigenous estuarine and marine Halomonadaceae, Pseudoalteromonadaceae, Rhodobacteraceae, and Shewanellaceae bacteria also harbored tetracycline resistance. All the six resistance determinants screened, tet(A)–(E) and tet(G), could be detected, and the predominant genes were tet(A), tet(B), and tet(G). Both anthropogenic activity-related and indigenous estuarine or coastal bacteria might contribute to the tet gene reservoir, and resistant bacteria and their molecular determinants may serve as bioindicators of coastal environmental quality. Our work probably is the first identification of tet(E) in Proteus, tet(G) in Acinetobacter, tet(C) and tet(D) in Halomonas, tet(D) and tet(G) in Shewanella, and tet(B), tet(C), tet(E), and tet(G) in Roseobacter. Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

绿绒蒿属一新变种

报道了绿绒蒿属一新变种,即椭圆叶红花绿绒蒿(MeconopsispuniceaMaxim.var.ellipticaZ.J.Cui etY.Sh.Lian)。     

安徽两种蜜蜂种群的春季繁殖及数量动态特征

1997～ 1999年在皖中和皖西、皖南山区对意大利蜜蜂 (ApismelliferaLigusticaSpi.)和中华蜜蜂(ApisceranaceranaFeb .)种群数量动态进行系统观察研究 .结果表明 ,蜜蜂种群数量明显受气候和蜜粉源植物的影响 ,周年呈现“两高”(春、秋 )和两低 (夏、冬 )的变化模式曲线 ;意大利蜜蜂春繁及秋季更新速度明显快于中华蜜蜂 ,但越夏效果不及中华蜜蜂 .意大利蜜蜂的性比值为 (314.4± 2 89.9)∶1～ (32 9.4± 30 5 .8)∶1,中华蜜蜂为 (334.2± 2 35 .5 )∶1～ (413 .1± 377.2 )∶1,雄蜂呈季节性出现 .蜜蜂种群内年龄组配在不断变化 .