转OvDREB2B基因陆地棉鉴定及其对水分渗透胁迫的分析

通过花粉管通道技术,以该实验室自育陆地棉品系TH₁和TH₂为材料,将诸葛菜(Orychophragmus vidaceus)抗逆转录因子OvDREB2B基因构建到植物表达载体后,导入棉花基因组,经卡那霉素筛选和分子鉴定表明目的基因已整合到棉花基因组中并表达。将T₁代转基因植株和受体对照在温室中栽培,待植株生长至四叶一心时,用不同渗透势的PEG-6000水溶液进行渗透胁迫处理,分析探讨转基因植株的抗旱效果及其抗旱机理。结果显示:当渗透势为0和0.5 MPa处理时,转基因植株和对照无明显差异;当渗透势为0.8 MPa和1.1 MPa处理时转基因植株较对照抗旱性明显提高。当渗透势为1.1 MPa处理96 h时,对照植株F_v/F_m降至0.2左右,而转基因植株仍正常生长,F_v/F_m值约为0.51,而且初始荧光（F₀）值、净光合速率（P_n）、胞间CO₂浓度（C_i）、蒸腾速率（T_r）等一系列参数转基因植株都明显优于对照,表明DREB2B基因能够提高棉花对水分胁迫的耐受性。     

微杆菌Sneb159杀线虫活性物质的分离与鉴定

【目的】有关Microbacterium maritypicum在植物线虫生物防治方面的研究较少,探究菌株M. maritypicum Sneb159的杀线虫活性,明确菌株发酵液中具有杀线虫活性的物质,为生物农药的开发提供理论依据。【方法】本研究检测了菌株Sneb159发酵液对大豆胞囊线虫二龄幼虫的触杀活性;并以触杀活性为追踪,采用有机溶剂萃取、硅胶柱层析及半制备高效液相色谱等技术对菌株Sneb159发酵滤液中的活性物质进行分离纯化;采用核磁共振波谱对纯化物进行结构鉴定。【结果】菌株Sneb159具有杀线虫活性,在24 h和48 h处理组中线虫的死亡率均显著高于对照组。从菌株Sneb159发酵滤液中分离得到杀线虫活性物质A6,经结构鉴定确定该物质为苯乙酰胺。【结论】首次发现M. maritypicum对大豆胞囊线虫的触杀作用,并且明确活性物质为苯乙酰胺。结果表明菌株M. maritypicum Sneb159和苯乙酰胺在大豆胞囊线虫的生物防治方面具有较好的应用潜力。     

Discovery of 4′-OH-flurbiprofen Mannich base derivatives as potential Alzheimer’s disease treatment with multiple inhibitory activities

A series of 4′-OH flurbiprofen Mannich base derivatives were designed, synthesized and evaluated as potential multifunctional agents for the treatment of Alzheimer’s disease. The biological screening results indicated that most of these derivatives exhibited good multifunctional activities. Among them, compound 8n demonstrated the best inhibitory effects on self-induced Aβ_1-42 aggregation (65.03% at 25.0?μM). Moreover, this representative compound also exhibited good antioxidant activity, biometal chelating ability and anti-neuroinflammatory activity in vitro. Furthermore, compound 8n displayed appropriate blood-brain barrier permeability. These multifunctional properties highlight compound 8n as promising candidate for further development of multi-functional drugs against AD.     

库布齐东段不同植被恢复阶段荒漠生态系统碳氮储量及分配格局

为科学评价植被恢复促进沙漠化逆转对碳氮储量的影响,以流动沙地、半固定沙地、油蒿固定沙地、柠条固定沙地、沙柳固定沙地5个阶段荒漠生态系统为研究对象,采用时空替代法分析植被恢复过程中荒漠生态系统碳氮储量及分配格局。结果表明:不同恢复阶段碳氮储量均表现为:流动沙地(3320.97 kg C/hm~2、346.69 kg N/hm~2)半固定沙地(4371.46 kg C/hm~2、435.95 kg N/hm~2)油蒿固定沙地(6096.50 kg C/hm~2、513.76 kg N/hm~2)柠条固定沙地(9556.80 kg C/hm~2、926.31 kg N/hm~2)沙柳固定沙地(19488.54 kg C/hm~2、982.11 kg N/hm~2)。植被层碳氮储量均呈现随植被恢复逐渐增加的趋势,除流动沙地外,其他阶段碳氮储量均以灌木层为主,占比分别为66.65%—91.41%和52.94%—93.39%,草本和凋落物占比较小。灌木各器官生物量及碳储量分配均为:茎根叶,氮储量分配无明显规律,草本各器官生物量及碳氮储量分配均为地上部分高于地下部分。土壤层是荒漠生态系统碳氮储量的主体,碳储量占比为68.64%—99.62%,氮储量占比为89.26%—99.89%,同样呈现随植被恢复逐渐增加的趋势。碳氮储量随土层加深逐渐降低,具有明显的表层富集特征,且随植被恢复过程富集性显著加强。这说明人工建植促进植被演替实现沙漠化逆转可以显著增强荒漠生态系统的碳氮固存能力。     

入侵植物马缨丹研究进展

马缨丹原产于热带美洲,现已扩散至世界热带和亚热带地区,并严重威胁入侵地本地植物的生长。马缨丹因具有观赏价值而被我国大量引进,但由于疏于管理,发展成为入侵杂草,对我国农业、畜牧业及生态环境造成严重危害。目前对马缨丹的入侵机制还没有全面系统的认识。本文从马缨丹的生物学特性、入侵机制、生态学效应、防治与应用等方面进行综述,总结其研究进展,以期为马缨丹的防治工作提供依据。研究结果显示:马缨丹成功入侵的关键因素源于其独特的生物学性征;对农林业造成的危害的原因主要为它的化感作用;马缨丹的防治方法主要包括物理、化学和生物防治;马缨丹在防虫除虫、污染修复、药用价值等方面有所应用。此外,分析当前研究中的不足后发现,今后应加强马缨丹在自然环境中的适应机制、应用潜力、防治方法等的研究。     

Cloning and tissue distribution of the human B3GALT7 gene, a member of the β1,3-Glycosyltransferase family

We report here the cloning and tissue distribution of the human B3GALT7 gene, a member of the beta1,3-Glycosyltransferase family, structurally related to the beta1,3-Galactosyltransferase family and beta1,3- N -acetylglucosaminyltransferase family, isolated from a human lung cDNA library. B3GALT7 is mapped to chromosome 19q13.2 by browsing the UCSC genomic database. It contains an ORF with length of 1191bp, encoding a protein with a signal peptide sequence and galactosyl-T domain, and its molecular weight and isoelectric point is predicted to be 43.3 kDa and 8.67 respectively. The molecular weight of the protein when expressed in E. coli corresponded to that expected. Northern blotting showed that B3GALT7 was highly expressed in lung, throat and ileum, whereas the expression level was low in tongue, breast, uteri, testis. In addition, it was also demonstrated that B3GALT7 is differentially transcribed in human tumor cell lines.     

Indole-3-Acetic Acid Production in <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> HP72 and Its Association with Suppression of Creeping Bentgrass Brown Patch

Pseudomonas fluorescens HP72, which suppresses the brown patch disease on bentgrass, produces several secondary metabolites, 2,4-diacetylphloroglucinol (2,4-DAPG), HCN, siderophore, and indole-3-acetic acid (IAA). In this study, IAA biosynthesis in strain HP72 was investigated. After several repeated subcultures, the spontaneous IAA low-producing mutant HP72LI was isolated. The IAA low production of the strain HP72LI was due to the low tryptophan side chain oxidase (TSO) activity. Colonization of strain HP72 on the bentgrass root induced root growth reduction, while strain HP72LI did not induce such growth reduction. The colonization ability of strain HP72 on the bentgrass root is higher than that of strain HP72LI. However, as for biocontrol ability, a significant difference in both strains was not detected. IAA production by strain HP72 may play a role in the construction of short root systems and take advantage of root colonization, but does not contribute to the biocontrol properties of P. fluorescens HP72. RID= ID= <E5>Correspondence to: </E5>S. Suzuki. Received: 9 September 2002 / Accepted: 7 October 2002     

Casparian strips in needles of Pinus bungeana: isolation and chemical characterization

By using cell wall degrading enzymes, Casparian strips were for the first time isolated from Pinus bungeana needle endodermis. They appeared as a fine network, similar to those isolated from roots. Fourier transform infrared spectroscopic analysis provided evidence that the Casparian strips were impregnated with lignin, suberin, cellulose and cell wall proteins.     

Backbone dynamics of the ribonuclease binase active site area using multinuclear ((15)N and (13)CO) NMR relaxation and computational molecular dynamics

The nano-pico second backbone dynamics of the ribonuclease binase, homologous to barnase, is investigated with (15)N, (13)C NMR relaxation at 11.74 and 18.78 T and with a 1.1 ns molecular dynamics simulation. The data are compared with the temperature factors reported for the X-ray structure of this enzyme. The molecular dynamics and X-ray data correspond well and predict motions in the loops 56-61 and 99-104 that contain residues that specifically recognize substrate and are catalytic (His101), respectively. In contrast, the (15)N relaxation data indicate that these loops are mostly ordered at the nano-pico second time scale. Nano-pico second motions in the recognition loop 56-61 are evident from (13)CO-(13)C cross relaxation data, but the mobility of the catalytic loop 99-104 is not detected by (13)CO cross relaxation either. From the results of this and previous work [Wang, L., Pang, Y., Holder, T., Brender, J. R., Kurochkin, A., and Zuiderweg, E. R. P. (2001) Proc. Natl. Acad. Sci. U.S.A., 98, 7684-7689], the following dynamical characterization of the active site area of binase emerges: a beta sheet, rigid at all probed time scales, supports the catalytic residue Glu 72. Both substrate-encapsulating loops are mobile on both fast and slow time scales, but the fast motions of the loop which contains the other catalytic residue, His 101, as predicted by B-factors and computational molecular dynamics is not detected by NMR relaxation. This work strongly argues for the use of several measures in the study of protein dynamics.