Growth ofNostoc muscorum mutants in the presence of diuron (DCMU) and L-methionine-DL-sulfoximine

Summary Diuron (DCMU) is inhibitory to the photoautotrophic and photoheterotrophic growth of the N₂-fixing blue-green algaNostoc muscorum at concentrations of 1.0×10^–5 M and 2.0×10^–5 M, respectively. A mutant of this organism resistant to 5.0×10^–5 M DCMU under its photoheterotrophic growth conditions, with the ability to utilize DCMU as a carbon and nitrogen source for growth, and complete inability to grow photoautotrophically has been isolated. With the apparent defect in its photosynthetic ability, it is suggested that theDCMU ^r mutant lacks the step inhibited by 1.0×10^–5 M DCMU, and metabolizes DCMU by an existing enzyme system in the absence of such inhibition. That this enzyme may be glutamine synthetase (GS) is explained with the help of a L-methionine-DL-sulfoximine (MSO)-resistant mutant ofN. muscorum which is able to grow faster with 2.0×10^–5 DCMU and is known to contain an altered GS.Thanks are due to the Council of Scientific and Industrial Research, CSIR Complex, Govt. of India, New Delhi-110012, for appointing the author to the Scientists' Pool for undertaking researches on the physiological and genetic controls of nitrogen metabolism in blue-green algae, a part of which is presented in this literature.     

Experimental study of gold distribution in the algae-organic matter-fluid system

Conclusion Gold distribution and transformation in algae-organic matter-fluid system is very complicated. Gold is first concentrated in kerogen after algae died. With the increase of dissolved organic matter owing to the increase of temperature and pressure, part of gold simultaneously emigrates from kerogen to DOM. When DOM forms organic fluid and emigrates from the strata, gold is simultaneously carried away by organic fluid in acidic condition, but by water in alkali condition. When the auriferous fluid flows through carbonaceous strata, gold in fluid is unloaded by kerogen. Gold migration in the system, accompanied by the evolution of algae-organic matter-fluid, provides the basic information of biometallogenetic evolution of gold.     

黄河兰州段藻类群落结构演替特征研究

2014年对黄河兰州段水体的浮游藻类调查结果表明,该段藻类的数量不同,随月份与水温变化差异明显,丰水期是藻类的爆发期,藻类数量最多达到63 700个/L;枯水期藻类数量最少10 800个/L.硅藻在藻类群落中占有优势地位,与黄河水体富含泥沙的特性息息相关,而绿藻类和蓝藻类在各断面的优势种属中也占据了一定的比例.兰州段各采样点氮磷比介于56~282之间,磷成为藻类生长的主要营养制约因子.藻类数量与水温呈明显的正相关.     

云南省丝状绿藻初报

报道了云南省的丝状绿藻１７属２９种，其中１７种是云南首次报道，３种为中国新记录．     

单胞藻浓缩、保藏及应用技术的初步研究

本文报道以明矾等为浓缩剂,对多种单细胞藻类进行浓缩和再培养,在比较的基础上,得出各种藻的较适浓缩剂及浓缩剂量。同时将浓缩的藻类经低温数月保存后,进行三级扩种培养和对中国对虾幼体及褶皱臂尾轮虫进行直接投喂效果试验,结果表明与常规培养藻无差异。     

海带热模拟实验的固体残余物研究及其石油地质意义

宏观底栖藻类作为海相烃源岩中重要的生油母质类型日益受到重视．通过对大型底栖褐藻海带的热模拟实验，利用傅立叶转换红外光谱、扫描电镜、漫反射光谱、反射率测定等分析和显微镜观察系统研究了海带的热演化规律，从有机质成熟度、残余物成分变化和实验样品的孔隙结构变化讨论了海带的石油地质意义．发现海带在较高的成熟度条件下依然具有较强的生烃能力，其孔隙发育规律对研究天然气的赋存和排出有着重要意义．     

混凝去除铜绿微囊藻(Microcystis aeruginosa)的效果研究

取纯培养条件下的铜绿微囊藻水样，分别用三氯化铁、聚合氯化铝、硫酸铝等3种药剂作混凝去除铜绿微囊藻烧杯试验，结果表明：聚合氯化铝混凝效果优于其他2种药剂，具有药剂投加量少(30～40mg／L)、矾花形成快、矾花沉降性能好、除藻效率高等特点．在聚合氯化铝最佳混凝条件下，投加聚丙烯酰胺助凝试验，发现添加6mg／L的聚丙烯酰胺只使除藻效率在原有基础上提高3％．铜绿微囊藻水样的pH对聚合氯化铝的混凝效果有明显影响，产生最佳混凝的pH值范围为6．0～7．0之间．     

浮游藻类群落结构动态与城市小水体水质的关系

比较了上海市徐汇区4个小水体3—5月浮游藻类群落结构和叶绿素a含量与水质的关系．康健公园内一条内河和上海师范大学内两个池塘种植水生高等植物和养殖鱼类，藻类数量少，叶绿素a含量低，修正的卡森营养状态指数TSIM(chl)处中营养状态，水质较好．桂林公园内一个池塘未种植水生高等植物和养殖鱼类，藻类数量多，叶绿素a含量高，修正的卡森营养状态指数TSIM(chl)处重营养状态，水质较差；并且4月由裸藻门的绿色裸藻(E．viridis)引起水华，水质恶化，处异常富营养状态．     

粘土存在下固定化海藻对金属离子吸附应用的研究

研究了在粘土存在下固定化海藻粉吸附含铅溶液的过程.结果表明:粘土与海藻混合后,对重金属的吸附量随海藻的含量的增加而增加.在pH=5时,最佳的比例为粘土比海藻为1:4.现场重金属废水处理(Cu2 、Pb2 、Cd2 、Ni2 )的平均吸附率大于70%.