Cleansing contaminated seawaters using marine cyanobacteria: evaluation of trace metal removal from the medium

The use of microbial biomass in biosorption is already being studied as a potential alternative to (or combined with) conventional processes, where several algae and microorganisms have already shown promising ability to uptake metals. Cyanobacteria (blue-green algae) are widespread organisms, with specific properties, such as high nutrient removal capacity and tolerance to highly variable conditions which make them well-suited for wastewater and remediation purposes. The main aim of this work was to evaluate the use of a marine cyanobacterium LEANCYA 21 (Synechocystis sp.), collected from the Portuguese southern border, for the removal of selected trace metals when in natural seawater culture medium. It was observed, for the first time, that this particular strain is capable of uptaking Pb, Ni and Zn (at nM levels) from seawater solutions using small amounts of biomass. Uptake values for Pb were up to 90% (0.75 mg g^?1 biomass) in 6 h. The specific biosorption curves of Ni and Zn showed that these metals follow a first order kinetics biosorption in batch conditions. Solutions containing multimetals have revealed that Ni uptake is affected by the presence of Pb and Zn. The calculated specific absorption values were high enough to predict a possible application in aquaculture where such low levels of metals may inhibit microalgae growth.     

QuEChERS提取-高效液相色谱-高分辨质谱法测定水产品中3种蓝藻毒素的含量

取水产品样品2.00g与2g无水硫酸钠混匀后加入提取剂10 mL甲醇,涡旋振荡5min后超声提取5 min,再离心5 min,取其上清液。在上清液中加入500 mg中性氧化铝和15mg石墨化碳黑(GCB)涡旋振荡1min,离心5min,取上清液,于40℃下吹氮至近干,用体积比为1∶1的流动相A-流动相B混合溶液溶解残渣并定容至2.0mL,经0.22μm滤膜过滤,取其滤液按高效液相色谱-高分辨质谱法测定其中3种蓝藻毒素的含量。色谱分离中用Hypersile Gold C8色谱柱(150mm×2.1mm,3μm)为固定相,用不同比例的流动相A和流动相B两溶液的混合液作为流动相进行程序梯度洗脱。质谱测定中采用电喷雾离子源,正、负离子切换模式。由于3种蓝藻毒素均产生基质减弱效应,制作工作曲线需用基质标准溶液以消除基质效应。结果表明:所测3种蓝藻毒素均在10~200μg·L^-1内与其峰面积之间呈线性关系,其检出限(3S/N)均为5μg·kg^-1。通过标准加入法进行回收试验,测得回收率为68.3%~104%,测定值的相对标准偏差(n=6)为7.7%~17%。     

A single microcystin in a toxic Microcystis bloom from the river Río de la Plata (Argentina)

Microcystis is one of the most common bloom-forming cyanobacteria genera in diverse ecosystems. More than 80% of its strains are toxic, mainly due to their ability to produce metabolites known as microcystins (MC). Here we report on a M. aeruginosa bloom that appeared in the summer of 2001 at a site of the Río de la Plata, within the city of Buenos Aires. The symptoms in mice indicated that the bloom was hepatotoxic. LC-PDA analysis revealed a similar high concentration (0.9–1?mg?g^–1?d w) of just one MC in the bloom biomass during the 3-month study period. During this period most of the MC (ca. 98 %) was found intracellularly, and the content remained almost the same. The molecular mass of the bloom MC was 1036?Da, as deduced from LC-ESI-MS data. Fragment ion analysis by LC-IT-MS-MS allowed identifying 6 out of the 7 amino acids, as well as their position in the molecule. The molecular mass of the unidentified amino acid residue was 155?Da. According to the data obtained, the MC under study was MC-XR, X representing the unidentified amino acid. This is the first report both on the characterisation of MCs in an urban site of the Río de la Plata waters, and on an Argentinean bloom exhibiting only one MC variant.     

控藻鲢鱼的捕捞策略

鲢鱼是一种以水中浮游动植物为食的滤食性鱼类,利用鲢鱼控制蓝藻数量是一种有效的纯生物手段.分析蠡湖鲢鱼资源稳定的条件,建立鱼量的基本方程式及利润模型,给出利润与捕捞强度的关系和鱼群数量的变化趋势.最后得到了鲢鱼的放流与回捕策略.     

Caldorin,a new polyketide from the marine cyanobacterium Caldora penicillata

A new polyketide with a cis-fused decalin ring scaffold, caldorin, was isolated from the marine cyanobacterium Caldora penicillata. The gross structure and relative configuration were elucidated by spectroscopic analyses. We also clarified that caldorin is a weak SOAT inhibitor and moderate osteoblast differentiation inhibitor. On the other hand, caldorin did not exhibit cytotoxicity against either HeLa or HL60 cells.     

Symbiodinolactone A,a new 12-membered macrolide from symbiotic marine dinoflagellate Symbiodinium sp.

A new 12-membered macrolide, symbiodinolactone A, was isolated from the culture broth of symbiotic marine dinoflagellate Symbiodinium sp. The gross structure of symbiodinolactone A was elucidated by spectroscopic analyses, and the relative configuration was elucidated by the J-based configuration analysis and density-functional theory calculations. Symbiodinolactone A is the new 12-membered macrolide possessing an E double bond between C-4 and C-5, a branched methyl group at C-7, and a 1,2,3-trihydroxybutyl group at C-11. Symbiodinolactone A is the first usual size macrolide and the first non-nitrogen-containing macrolide from dinoflagellate Symbiodinium sp. Symbiodinolactone A might be generated by the unexplained dinoflagellate polyketide biosynthetic machinery.     

Durinskiol A: a long carbon-chain polyol compound from the symbiotic dinoflagellate Durinskia sp.

A long carbon-chain polyol compound with a molecular weight of 2128 mu, durinskiol A (1) was isolated from the cultured symbiotic dinoflagellate Durinskia sp. Its planar structure was elucidated based on 2D-NMR and MS/MS analysis. Durinskiol A (1) caused a short body length, abnormal pigment pattern, and pericardiac and yolk-sac edema in zebrafish.     

光照强度对蛇足石杉共生蓝藻细胞悬浮培养的影响

以蛇足石杉孢子囊为材料,分离出蛇足石杉共生蓝藻细胞,研究光照强度对液体培养的共生蓝藻细胞生长的影响.研究结果表明,在光强500 Lx下,共生蓝藻的生长速率最大;增加光照强度(> 2000 Lx)将抑制共生蓝藻的生长,菌体褪绿变白;在共生蓝藻生长过程中,蓝藻细胞内叶绿素a的含量随着光强的增加而显著减少,这与其在强光照下生物量的降低呈正相关.不同光质实验结果表明,绿光和蓝光条件下蛇足石杉内生藻生长快而红光条件下藻体增殖最慢,这与在绿光和蓝光条件下藻体细胞合成的色素含量增高有密切的关系.实验结论:蛇足石杉共生蓝藻细胞适宜的光照条件是弱光光照,适宜的光质是绿光或蓝光.     

Utilization of cyanobacteria in photobioreactors for orthophosphate removal from water

The effectiveness of photosynthetic free-living and polyurethane foam (PU) immobilized Anabaena variabilis cells for, removal of orthophosphate (P) from water in batch cultures and in a photobioreactor was studied. Immobilization in PU foams was found to have a positive effect on P uptake by cyanobacteria in batch cultures. The efficiency of P uptake by immobilized cells was higher than by free-living cells. A laboratory scale photobioreactor was constructed for removal of P from water by the immobilized cyanobacteria. The photobioreactor was designed so that the growth medium (water) from a reservoir was pumped through a photobioreactor column with immobilized cyanobacteria and back to the reservoir. This created a closed system in which it was possible to measure P uptake. No leakage of cells into the photobioreactor medium reservoir was observed during the operation. The immobilized cells incorporated into a photobioreactor column removed P continuously for about 15 d. No measurable uptake was demonstrated after this period. Orthophosphate uptake efficiency of 88–92% was achieved by the photobioreactor.     

Maedamide,a novel chymotrypsin inhibitor from a marine cyanobacterial assemblage of Lyngbya sp.

Maedamide, a novel chymotrypsin-inhibiting depsipeptide, was isolated from a cyanobacterial assemblage that mostly consisted of Lyngbya sp. Its structure was elucidated by spectroscopic analyses and chiral HPLC analyses of hydrolysis products. Maedamide selectively inhibited chymotrypsin but not elastase and trypsin. In addition, Maedamide strongly inhibited the growth of HeLa cells and HL60 cells.