The adaptability of three Arctic microalgae to different low temperatures

In order to study the adaptability of Arctic mieroalgae to different environmental temperatures, the growth curves and antioxidase system of three microalgae ( Skeletonema marinoi, Chlorella sp. and Chlam ydomonas sp. ) that were separated from the Ny-Alesund, the high Arctic, at different low temperatures (0 ℃, 4 ℃ and 8 ℃ ) were determined. The result showed that the adaptability of the microalgae to temperatures depended on the species. The growth rate, SOD and CAT activities of Skeletonema marinoi were the highest at 4 ℃,but MDA content was the lowest. The growth rate and enzyme activity of Chlorella sp. were the highest at 8 ℃, while the lowest MDA content presented at 0 ℃. The growth of Chlamydomonas sp. at the different temperatures was not so significant, the lowest MDA content presented at 8 ℃. The change of antioxidase system also depended on species and temperatures. Three indexes of antioxidase system of Skeletonema marinoi between 0 ℃ and 4 ℃ showed extremely significant difference (p < 0. 01 ). SOD activity of Skeletonema marinoi and Chlorella sp. between 0 ℃ and 8 ℃ showed significant difference (p<0.05),and the other two indexes of them differed insignificantly. Antioxidase systems of Chlamydomonas sp. at the three temperatures differed insignificantly. In conclusion, the three microalgae had good adaptability to the three temperatures;their MDA content presented a low level, and had unique physiological mechanism to adapt to the environment with different low temperatures.     

藏南白垩纪黑色页岩和大洋红层的活性铁埋藏记录及其古海洋意义

由于白垩纪黑色-红色沉积转变涉及温室气候条件下的全球变化和碳-氧循环等重要科学问题,因此已成为国际白垩纪研究领域新的重要方向[1].     

The acid lakes and rivers of Copahue Volcano, Argentina

Copahue is an active volcano in the Andes （Argentina, 37.5 S, 71 W） with an acid crater lake, acid chloride-sulfate hot springs feed the Upper Rio Agrio River that discharges into glacial Lake Caviahue. The Lower Rio Agrio outlet mixes with non-acidic meteoric waters, which leads to abundant precipitation of poorly crystalline yellow flocs. Further dilution and neutralization downstream lead to the precipitation of Al-rich material. This river and lake system is an extreme example of a naturally acidified watershed with similarities to streams impacted by acid mine drainage. We determined the chemistry and element fluxes of the Copahue-Caviahue system between 1997 and 2006, and this time series carries data from before, during and after the 2000 Copahue eruptions. The crater lake and hot springs had pH〈0.5 prior to the eruption with up to 6.5 % sulfate and 1% chloride. The fluids were saturated relative to gypsum/anhydrite and copper sulfides. Sulfur isotope studies suggested that the sulfate and associated acidity of the water formed from the disproportionation of magmatic SO2 at about 300℃. Just prior to the eruption, the fluids became saturated with additional minerals, including jarosite and hematite. The Upper Rio Agrio bed became coated with bright red hematite in 2004. Mixing with glacial meltwater increases the pH of the Upper Rio Agrio to values of 1-2, and the input of the Upper Rio Agrio has gradually acidified Lake Caviahue to pHi2.5. Annual element fluxes through the Upper Rio Agrio before the eruption were on the order of 15000 tounes Cl, 25000 tounes SOn and 1500 tounes F, with large outputs of dissolved rock contents as well. Annual volcanogenic trace element fluxes through the river include 7.5 tounes As, 5 tounes B and 0.6 tounes Li. After the eruption, the system became more dilute, the element fluxes decreased and Lake Caviahue became less acidic （pH≈2.8）. In the spring of 2006, the hot springs and crater lake had pH values〈 0.5 once again, suggesting that the system is becoming more active again.     

泥蚶血红蛋白的制备及其抗菌活性研究

利用凝胶层析技术从泥蚶血细胞裂解物中分离纯化得到两种血红蛋白,回收率为74.3%,并通过Tricine-SDS-PAGE和质谱技术鉴定为Tg-HbⅠ(同源二聚体)和Tg-HbⅡ(异源四聚体)。分别通过琼脂扩散法和分光光度法测其抗菌活性和过氧化物酶活性,结果发现,两种Tg-Hb对大肠杆菌和恶臭假单胞杆菌均有抗菌活性,Tg-HbⅡ对于恶臭假单胞菌和大肠杆菌的MIC值分别为0.063mg/mL和0.13mg/mL,Tg-HbⅠ对两种菌的MIC均为0.048mg/mL;两种Tg-Hb均具有过氧化物酶活性,能催化愈创木酚、邻苯二酚、对苯二酚、苯酚、左旋多巴等多种酚类物质。在Tg-Hb中添加GSH后,两种Tg-Hb均不再对恶臭假单胞杆菌具有抗菌活性。可见,两种Tg-Hb对恶臭假单胞杆菌等的抗菌活性均是通过其过氧化物酶活性发挥作用的。     

海洋沉积物来源真菌嗜松青霉SD-272 代谢产物研究

对来源于珠江口沉积物的一株海洋真菌嗜松青霉(Penicillium pinophilum)SD-272的次生代谢产物,进行了化学成分分离及其生物活性研究。采用常规硅胶柱层析、凝胶Sephadex LH-20柱层析、制备薄层层析等分离手段,通过紫外、核磁共振技术、质谱技术等现代波谱学技术,从其发酵液提取物中共分离并鉴定了13个化合物,分别为:4'-demethylvermistatin(1),vermistatin(2),penisimplicissin(3),deoxyfunicone(4),5,6-epoxy-3-deoxyfunicone(5),5′-methoxy-6-methyl-biphenyl-3,4,3′-triol(6),altenusin(7),1-deoxyrubralactone(8),kojic acid(9),7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone(10),dankasterone(11),4-hydroxy-2-methoxyacetanilide(12),N-(2-hydroxypropanoyl)-2-aminobenzoic acid amide(13)。这些化合物均为首次从嗜松青霉中分离得到,其中化合物11显示较好的卤虫致死活性,LD50值为39.2μmol/L。     

厦门海域环境与功能区划符合性分析

文章根据2007年厦门市海洋功能区划的标准,将2007-2012年厦门海域环境状况与海洋功能区划环境要求做对比,发现厦门海域在海水环境方面基本符合区划制定的环境保护要求。厦门海水水质主要污染物无机氮与活性磷酸盐,总体呈增加趋势,而在2009年突然大幅下降,随即在2010年该数值有所回升。文章就这一现象进行分析讨论,为将来修编厦门海洋功能区划能更切合环境使用实际、避免造成海域环境污染、形成良好的海洋开发和管理秩序、为厦门海域资源的可持续利用提供参考。     

极地抗植物病原真菌活性菌株PKS和NRPS基因的克隆与分析

植物常见病原真菌尖孢镰刀菌(Fusarium oxysporum)为指示菌,采用平板扩散法对实验室保藏的38株极地细菌进行了抑菌活性验证,并对其中活性较强的菌株进行了分子鉴定与系统发育分析及次级代谢产物合成功能基因(PKS和NRPS)的克隆与分析。结果表明,38株极地细菌中,13株具有明显的抗病原真菌活性;分子鉴定与系统发育分析表明,11株活性菌株属于Pseudomonas,1株属于Psychrobacter,1株属于Arthrobacter;对活性菌株PKS和NRPS基因的克隆与分析表明,从10株活性菌株克隆到12条NRPS A结构域基因片段,其中5株活性菌株同时含有PKS I型KS结构域基因片段。据此为从聚酮和非核糖体肽等生物合成途径深入研究活性菌株的次级代谢产物提供了基因学证据。     

海洋放线菌Y18的分子鉴定、生物活性及其抗菌物质发酵条件优化

从北冰洋楚科奇海海洋沉积物中分离到一株放线菌Y18,其良好生长需要海水。经16S rRNA基因序列分析确定该菌株属于拟诺卡氏菌属(Nocardiopsis),次级代谢产物合成酶基因及抗菌活性筛选发现,它含有聚酮类Ⅱ型(PKSⅡ)和非核糖体含硫多肽类(non ribosome-bound sulfur-containing peptides,NRPS)化合物合成酶基因,并且对枯草芽孢杆菌和白色念珠菌有抑制作用。以枯草芽孢杆菌为指示菌对Y18的发酵条件进行了初步优化,适合的发酵条件为:发酵培养基(蛋白胨2 g,酪素水解物2 g,酵母膏2 g,葡萄糖1 g,海水1 L),种子液接种量4%,发酵温度28℃,发酵培养基初始pH值8.0,培养时间6天,1 000 mL三角瓶装液量20%。并对Y18发酵液稳定性进行了测定,结果显示:发酵液对酸碱、热的稳定性都较强,4℃下贮藏发酵液的抗菌活性保留时间较长。