Toxicity of lipid-soluble copper(II) complexes to the marine diatom Nitzschia closterium: Amelioration by humic substances

Algal assays, using the marine diatom Nitzschia closterium, have established that humic acid (5 mg kg⁻¹) can ameliorate the toxicity of the lipophilic complex Cu(oxine)₂ (3 × 10⁻⁸ mol l⁻¹ in unsupplemented seawater). The toxicity of Cu(PAN)₂ is not ameliorated [PAN = 1-(2-pyridylazo)-2-napthol]. In conjunction with previous visible absorption spectrophotometry and polarographic measurements it was established that humic acid sequesters copper(II) from the hydrophobic complexes, releasing a ligand molecule. The copper(II) toxicity may be ameliorated provided the ligand itself is not toxic.Fulvic acid was significantly less effective in ameliorating toxicity. Because of the significant competition from Ca(II) and Mg(II) in seawater, it is inferred that humic substances may be more effective in ameliorating toxicity of hydrophobic copper complexes in fresh water.     

混凝—气浮除藻工艺中各参数的优化

以聚合氯化铝(PAC)为混凝剂,采用混凝-气浮工艺处理含藻原水,确定了该工艺的最佳运行参数.结果表明,在原水中铜绿微囊藻的含量为(1.90～2.04)×1010个/L的条件下,当PAC投量为20 mg/L、快速混合G值为500 s-1(60 s)、一级絮凝的G值为100 s-1(4 min)、二级絮凝的G值为20 s-1(4 min)、溶气水回流比为10%、气浮紊动强度G值为9.5 s-1、气浮接触时间为75 s、静置时间为3 min时处理效果最好.     

Binding of Cu(II) to algae in a metal buffer

The interactions of Cu(II) with algal surfaces and exudates were studied in metal-NTA buffers by a combination of several analytical techniques. Suspensions of living algae in the presence of NTA were titrated at constant pH with Cu(II). The various Cu species were determined as follows: a copper ion selective electrode was used reliably in the pCu range 9–12; differential pulse polarography was used to measure separately Cu(II)-NTA complexes and labile Cu(II) species and to evaluate the complexation of copper by ligands in solution; copper bound to the algal surfaces was extracted by acid treatment and measured by AAS. Thus, we determined both the binding of Cu to the algal surfaces and to exudates excreted by the algae. The results were interpreted in terms of conditional equilibrium constants valid at a given pH; the conditional constants, both for the binding to the surfaces and with the exudates increase in the pH range 5.0–6.5. Simple equilibrium models using the experimentally determined binding capacities and equilibrium constants were able to simulate the results and to evaluate the speciation of copper. Under the experimental conditions used, the binding of Cu(II) to algal exudates has a more significant effect on copper speciation than the binding to the algal surfaces. These extracellular ligands may play an important role in decreasing the concentration of free copper ion and thus mitigating the potential toxic effects in organisms.     

二氧化氯在循环冷却水中的应用

本文介绍了ＣｌＯ２作为杀菌灭藻剂的工艺机理,在工业循环水中的杀菌灭藻效果,并对其进行经济性比较。     

五株海藻次级代谢产物化学筛选

海藻是海洋中未开发完全的生物新资源,富含各种有利用价值的活性代谢产物。为了确定海藻中次级代谢产物的丰富度,该实验利用化学筛选方法（薄层层析色谱（TLC）、高效液相色谱（HPLC）、气相色谱-质谱（GC-MS））对江篱、刺麒麟菜、异枝麒麟菜、石花菜及小球藻这五株海藻中的次级代谢产物进行初步筛选。结果表明,通过薄层层析色谱和高效液相色谱分析得出江蓠和石花菜显色明显,代谢产物丰富且易于提取分离。通过气相色谱-质谱分析色谱分析得出,石花菜、小球藻的石油醚相成分复杂,未知化合物较多,特别是石花菜和小球藻可以进行重点研究,为后续海藻活性代谢产物研究与应用上的研发提供有力的实验基础。     

蛋白质组学技术在藻类研究中的应用现状与展望

藻类具有复杂多样的进化历史和生物学特征,不仅在生态系统中扮演着重要角色,而且具有许多独特的基因和生物过程。随着后基因时代的到来,组学技术受到各界学者的高度重视,近年来在藻类研究中也得到了应用。高通量技术在藻类研究领域中的应用,也大大促进了藻类蛋白质组学的发展。本文综述了蛋白质组学技术在藻类品质差异鉴定、养殖胁迫作用、生理机制方面的研究进展,并对其发展方向和应用前景进行了展望,为从事藻类组学的研究者提供参考。     

预氧化处理微污染水库水中优势藻类试验研究

采用高锰酸钾复合药剂对水库水中的藻类及优势藻类的去除效果进行了研究．试验结果表明：高锰酸钾复合药剂对水库水中的藻类有较好的去除效果,对某些优势藻类的去除效果更加明显．同时,探讨了高锰酸钾复合药剂预氧化处理优势藻类的机理．     

藻类对微量元素的生物富集及其机理探讨

介绍了藻类生物富集微量元素的特点和研究现状,探讨了藻类生物富集的作用机理。藻类对有益微量元素的富集作用大于毒性元素;藻类生物富集微量元素的作用机理主要为生物吸附和主动运输,并以主动运输途径富集的微量元素具有较高的生物活性。     

Physico‐chemical Characterization of Floridean Starch of Red Algae

The current work reports on isolation and physico‐chemical characterization of floridean starch from three species of agarophytic macro red algae. As determined by ¹H‐NMR spectroscopy, the average chain length and degree of branching frequency of this starch were 18 and 4.8, respectively. According to its amylopectin chain length distribution obtained by Dionex analysis, the crystalline polymorph of floridean starch from the red alga Gracilariopsis lemaneiformis was deduced to be C‐type and this was further supported from its X‐ray crystallographic pattern. Enzymatic analysis of its glucose 6‐phosphate content showed that floridean starch had a low level of covalently linked phosphate (1 nmol per milligram starch) and this was further confirmed by ³¹P‐NMR. The absorbance peak of floridean starch with iodine occurred at 527—530 nm and the blue value was low (0.1), indicating the absence of amylose, which was confirmed by differential scanning calorimetry (DSC). Floridean starch exhibited low gelatinization temperature, low viscosity, high clarity and little or no retrogradation upon repetitive freeze‐thaw cycles, as studied by DSC and rapid viscosity analysis (RVA). These results are discussed in light of the functional properties and the structure of floridean starch.