Resistance function of rice lipid transfer protein LTP110

Plant lipid transfer proteins (LTPs) are a class of proteins whose functions are still unknown. Some are proposed to have antimicrobial activities. To understand whether LTP110, a rice LTP that we previously identified from rice leaves, plays a role in the protection function against some serious rice pathogens, we investigated the antifungal and antibacterial properties of LTP110. A cDNA sequence, encoding the mature peptide of LTP110, was cloned into the Impact-CN prokaryotic expression system. The purified protein was used for an in vitro inhibition test against rice pathogens, Pyricularia oryzae and Xanthomonas oryzae. The results showed that LTP110 inhibited the germination of Pyricularia oryzae spores, and its inhibitory activity decreased in the presence of a divalent cation. This suggests that the antifungal activity is affected by ions in the media; LTP110 only slightly inhibited the growth of Xanthomonas oryzae. However, the addition of LTP110 to cultured Chinese hamster ovarian cells did not retard growth, suggesting that the toxicity of LTP110 is only restricted to some cell types. Its antimicrobial activity is potentially due to interactions between LTP and microbe-specific structures.     

真菌细胞溶壁酶的产酶培养和应用效果

从土样中分离的７１株木霉（Ｔｒｉｃｈｏｄｅｒｍａ ｓｐ．）筛选出一株分解几丁质和葡聚糖能力较强的菌株。该菌株在麸皮、稻草粉、硫酸铵和诱导物为主成份的固体培养基上,经过２５℃、８４ｈ的培养,产生较高的真菌细胞溶壁酶,能溶解酵母、毛霉、黑曲霉及食用菌等丝状菌丝体的细胞壁,形成原生质体,经选用酵母、毛霉等进行原生质体再生,效果较优。     

一株可同时降解多种高环PAHs的丝状真菌——宛氏拟青霉(Paecilomyces variotii)

采用液体培养的方法,分离纯化了丝状真菌宛氏拟青霉(Paecilomyces variotii)并研究了其对苯并[a]蒽、苯并[a]芘、苯并[b]荧蒽、苯并[k]荧蒽、茚并[1,2,3-cd]芘的降解效果.结果表明:接种处理30 d,该菌株对混合体系中5种PAHs的降解率为16.1%～24.6%,而对单一体系中的降解率为10.4%～33.3%;同时,对单一与混合体系中PAHs的降解作用存在一定差异,苯并[k]荧蒽和苯并[b]荧蒽在单一体系中降解率增大,而其他种类的则减小.本研究结果为高环多环芳烃共代谢机理研究和多环芳烃复合污染水土环境的生物修复提供了一种新的种质资源.     

Comparative studies of four protein preparation methods for proteomic study of the dinoflagellate Alexandrium sp. using two-dimensional electrophoresis

Alexandrium is a wide-spread genus of dinoflagellate causing harmful algal blooms and paralytic shellfish poisoning around the world. Proteomics has been introduced to the study of Alexandrium, but the protein preparation method is still unsatisfactory with respect to protein spot number, separation and resolution, and this has limited the application of a proteomic approach to the study of dinoflagellates. In this study we compared four protein preparation methods for the two-dimensional electrophoresis (2DE) analysis of A. tamarense: (1) urea/Triton X-100 buffer extraction with trichloroacetic acid (TCA)/acetone precipitation; (2) direct precipitation with TCA/acetone; (3) 40 mM Tris (hydroxymethyl) aminomethane (Tris) buffer extraction; and (4) 50 mM Tris/5% glycerol buffer extraction. The results showed that, among the four protein preparation methods, the method combining the urea/Triton X-100 buffer extraction and TCA/acetone precipitation allowed detection of the highest number and quality of protein spots with a clear background. Although the direct TCA/acetone precipitation method also detected a high number of protein spots with a clear background, the spot number, separation and intensity were not as good as those obtained from the urea/Triton X-100 buffer extraction with TCA/acetone precipitation method. The 40 mM Tris buffer and 50 mM Tris/5% glycerol buffer methods allowed the detection of fewer protein spots and a pH range only from 4 to 7. Subsequently, the urea/Triton X-100 buffer extraction with TCA/acetone precipitation method was successfully applied to profiling protein expression in A. catenella under light stress conditions and the differential expression proteins were identified using MALDI TOF–TOF mass spectrometry. The method developed here appears to be promising for further proteomic studies of this organism and related species.     

湿地生态旅游研究进展

湿地富有生物多样性和文化多样性,具有较高的旅游价值、环境教育功能及社区参与功能,湿地生态旅游体现了旅游经济与湿地保护的可持续协调发展,目前已引起国内外政府和学者的普遍关注. 本文对国内外相关研究理论和实践进行了总结,对湿地生态旅游的研究意义、进程、内容、方法和结果等进行了综述,并对湿地生态旅游研究进行了展望,以期推动湿地生态旅游研究的发展,为湿地及相关旅游区的资源开发、环境保护和科学管理提供参考.     

南方鲇血型的初步鉴定

本研究旨在通过观察南方鲇血清与其红细胞的交叉反应以鉴定南方鲇的血型.实验结果表明:南方鲇的血清与同种其他个体的红细胞进行交叉反应时均未出现凝集现象,这表明南方鲇可能不存在血型或南方鲇具备血型但血清中相应的凝集素含量不足.以南方鲇的红细胞为抗原免疫日本种大耳白兔制备的抗血清与南方鲇的红细胞进行交叉反应,出现了不同程度的凝集反应,这表明南方鲇存在血型.据上述两个实验结果可以推断,南方鲇可能存在4种血型,分别命名为NA、NB、NAB和NO型;同时也证实,在鉴定南方鲇血型的研究中,通过制备抗血清与红细胞进行交叉反应的方法更为可靠.     

枯草芽孢杆菌CAS15嗜铁素基因dhbC的克隆、表达及功能鉴定

通过PCR技术扩增得到dhbC基因,对其进行序列分析发现,dhbC基因片段长为1197bp,预期编码398个氨基酸,蛋白分子量大小为43.8kD。将目的片段连接到表达载体pET-30a(+),转化大肠杆菌Escherichia coli BL21(DE3)获得重组菌株BL21(DE3)/pET-30a-dhbC,以IPTG在30oC诱导4h实现高效表达,获得一个分子量为48.8kD的融合蛋白。重组蛋白可溶性分析结果表明:融合蛋白主要为可溶性蛋白。Western blotting分析结果表明:重组蛋白可与兔抗His-tag多克隆抗体发生特异性反应,在48.8kD处有特异条带,与预期结果一致,证明重组质粒中含有dhbC基因。通过同源重组的策略将dhbC基因敲除后重新导入,验证了dhbC基因与嗜铁素的生物合成密切相关。     

极地雪藻在不同培养基中生长和虾青素累积的研究

在常温（23℃）和低温（10℃）条件下,用BBM、Bold 1NV、TAP和MCM四种培养基对极地雪藻进行培养。通过对生长速率、细胞数、A535值及虾青素累积量的测定,比较不同培养基、不同培养条件对极地雪藻的生长与虾青素累积的影响。结果表明,低温有利于极地雪藻的生长和虾青素的累积,BBM培养基比其它培养基更适合极地雪藻的生长,10℃时条件下其生长速率最高,培养14d细胞数可达到3．53×10^6／mL;在高光强条件下培养15d后用BBM培养基培养的极地雪藻细胞的虾青素累积为其它培养基的2．21-3．59倍。     

Potential of a simple solid-phase extraction method coupled to analytical and bioanalytical methods for an improved determination of microcystins in algal samples

Artemia assays and protein phosphatase assays are commonly used for the screening of microcystins (MCs) in algal samples instead of the standard mouse toxicity assay. However, it has been shown that their results are often biased because of the matrix effects. To eliminate the possible interferences in the algal matrices, a new solid-phase extraction (SPE) method using silica gel as a sorbent was developed and evaluated. Results show that this SPE method could not only reduce the toxicity of the Microcystis samples towards brine shrimp by 50-80% but also eliminate 90-100% of the endogenous phosphatase activity from Spirulina and Chlorella samples, thus improving the determination of microcystins in algal samples using either of the two bioanalytical methods. The application of this SPE method as an off-line cleanup for high-performance liquid chromatography (HPLC) with UV detection is also described in this study. After SPE, the HPLC chromatograms of Microcystis samples have clear baselines that have no interferences with the analyte peaks.