Antioxidant capacity of the algae using a biosensor method

Three different methods, i.e. a biosensor method, a voltammetric method and a spectrophotometric method, have been used to evaluate the total antioxidant capacity of certain types of algae. In the final evaluation of the data also the variation in time of the antioxidant capacity of cultivated algae was considered and some experimental factors, such as the use of different solvent mixtures to extract the antioxidant substances contained in the algae, were discussed.     

Preparation of TiO2-coated hollow glass beads and their application to the control of algal growth in eutrophic water

Photocatalytic inactivation of algae, Anabaena, Microcystis and Melosira, was carried out with the TiO₂-coated pyrex hollow glass beads under the illumination of UV-A light. After being irradiated with UV-A light in the presence of the TiO₂-coated pyrex glass beads, Anabaena and Microcystis, known as typical cyanobacteria, lost their photosynthetic activity, and the string of Anabaena cells and the colonies of Microcystis cells were completely separated into individual spherical one. In the case of Melosira, which is a typical diatom, however, somewhat lower photocatalytic inactivation efficiency was obtained, which was believed to be due to the presence of the inorganic siliceous wall surrounding the cells of Melosira. The TiO₂-coated hollow glass beads could successfully be employed for the practical application at the eutrophicated river under sunlight. More than 50% of the chlorophyll-a concentration could be reduced by the action of TiO₂ photocatalysis.     

Dewatering characteristics of algae-containing alum sludge

The presence of algae in source waters not only causes problems in the water treatment process, but also complicates the treatment and disposal of sludge. This has become a major concern in Taiwan because of the increasing eutrophication of water sources. The purpose of this study was to determine the effects of algae during aging process on the characteristics of potable water treatment residuals and investigate their conditioning in order to provide water treatment plants with guidelines for treating algae-containing sludge. In this study, we measured the bound water content and CST to evaluate the influence of algae and their exudates on sludge conditioning. The change in zeta potential was monitored during sludge aging. During the aging process up to 5 days, the surface charge of sludge became more negative and the dewaterability was enhanced by algal exudates. Microphotographs of the algae-containing sludge suggest that algae and their exudates cause the bio-flocculation phenomenon.     

用氢化物—原子荧光光谱法测定海藻样品中的铅

报道了应用ＡＦＳ－２００１双道原子荧光光度计测定海藻样品中有毒元素Ｐｂ的结果，该法的检出限为０．４７μｇ／Ｌ。     

Determination of organotins in aquatic plants by headspace SPME followed by GC-PFPD determination

Optimal conditions of headspace solid-phase microextraction followed by gas chromatography coupled to pulsed flame photometric detection (SPME–GC–PFPD) have been investigated to validate the analysis of 11 organotin compounds in plant matrices including methyl-, butyl-, and phenyltin compounds. The extraction of organotin compounds from vegetal matrices has been carried out using optimized conditions of HCl-based extraction. The use of headspace SPME to preconcentrate the analytes allowed most of the detection limits to be obtained sub-0.5?ng(Sn)?g^?1. The precision evaluated using RSD with six replicates ranges between 5 and 10% (except for triphenyltin: 17%). The accuracy of the method was validated on spiked or polluted vegetal samples taken from Bizerte Lagoon (Tunisia) and by comparison with classical liquid–liquid extraction (LLE). These results highlight the suitability of the selected method for organotin control in complex environmental matrices such as aquatic plants.     

Amperometric Algal Chlorella vulgaris Cell Biosensors Based on Alginate and Polypyrrole‐Alginate Gels

The successful development and analytical performances of two biosensor configurations based on the entrapment of algal cells of Chlorella vulgaris into either a regular alginate gel or a newly synthesized pyrrole‐alginate matrix are reported. These biosensors were compared in terms of their amperometric current measurements to p‐nitrophenyl phosphate when used as substrate for the detection of an algal alkaline phosphatase activity. The high stability of the pyrrole‐alginate gel when compared to that of the alginate coating is herein demonstrated.     

Stable Carbon Isotope Fractionation in Lower Plants from the Schirmacher and Untersee Oases (Central Dronning Maud Land,East Antarctica)

Abstract

Lower plants (algae, lichens, mosses) from the Antarctic continent have been analysed for their stable carbon isotope composition. In contrast to lichens and mosses which exhibit quite normal δ¹³C-values the studied microbial benthos is characterized by an extremely low carbon isotope fractionation (δ¹³C-values up to ?1.4‰. vs. PDB). Limited CO₂ availability and bicarbonate uptake are probably the main factors responsible for this phenomenon.     

Absorption and Fluorescence Properties of Chromophoric Dissolved Organic Matter Produced by AlgaeSCIEI北大核心CSCD

Four kinds of diatom (Chaetoceros curvisetus, Phaeodactylumtricornutum, Nitzschia closterium f. minutissima and Navicula halophile) and two kinds of dinoflagellates (Prorocentrum donghaiense and Gymnodinium) were cultured under laboratory conditions. Variations of optical properties of chromophoric dissolved organic matter (CDOM) were studied with absorption and fluorescence excitation-emission matrix spectroscopy(EEM) during growth of marine microalgae in incubation experiment. Absorption spectrum revealed absorption coefficient a(355) (CDOM absorption coefficients at 355 nm) of 6 kinds of marine microalgae above increased by 64.8%, 242.3%, 535.1%, 903.2%, 836% and 196.4%, respectively. Simultaneously, the absorption spectral slope(Sg), determined between 270 and 350 rim, representing the size of molecular weight of CDOM and humic-like composition, decreased by 8.7%, 34.6%, 39.4%, 53.1%, 46.7%, and 35.7%, respectively. Applying parallel factor analysis (PARAFAC) together with EEM got four components of CDOM: C1(Ex/Em=350(260) nm/450 nm), C2 (Ex/Em=260 (430) nm/525 nm) 03 (Ex/Em=325 nm/400 nm) and C4(Ex/Em=275 nm/325 nm), which.were relative to three humic-like and one protein-like fluorescent components of Nitzschia closterium f. minutissima and Navicula halophile. In incubation experiment, fluorescence intensity of these four components during growth of Nitzschia closterium f. minutissima increased by, respectively, 8.68, 24.9, 7.19 and 39.8 times, and those of Navicula halophile increased by 2.64, 0.07, 4.39 and 12.4 times, respectively. Significant relationships were found between the fluorescence intensity of four components of CDOM, a(355) and Sg. All results demonstrated that both content and molecular weight of CDOM produced by diatom and dinoflagellate studied in incubation experiment increased, but these two parameters changed more obviously of the diatom than those of dinoflagellate; the proportion of humic-like components in the composition of CDOM also increased clearly with the growth of marine microalgae, but protein-like fluorescent component had only a slow growth. Furthermore, the absorption spectrum of CDOM produced by different species of algae changed obviously and the relative composition fluorescence intensity of CDOM produced by different microalgae were found to vary among different composition from EEM, which suggested CDOM produced by different microalgae make quite different contributions to CDOM in natural seawater.     

A Study of the Background Absorption of Slurry Algae in the Graphite Furnace Atomic Absorption Spectrometry

In general, biological organisms have the ability to absorb a specific element selectively. Holcombe and his co-workers reported that copper, nickel and cobalt could be separated from riverine and sea-water samples and cadmium from river water samples by unicellular green algae and were determined by slurry GFAAS. Dar-     

海藻鹧鸪菜化学成分的研究

海藻鹧鸪菜（ＣａｌｏｇｌｏｓａＬｅｐｒｉｅｕｒｉ,Ｊ．Ａｇｒａｒｄｈ）种属于红藻松节科,民间广泛用作驱虫药物．有关鹧鸪菜的化学成分报道很少［１,２］,已知有甾醇、甘露醇．为了进一步寻找其生理活性物质,我们对采自于中国南海西沙群岛海域样品的化学成分进行...