Oxidative stress in the hydrophilic medium of algae and invertebrates

The harmful effects of the reactive species may be due to the increase in their steady state concentration either by the enhancement of their production rates and/or the decrease of their consumption rate by antioxidant activity. The ascorbyl radical (A^• ) can be considered as a final product of radical oxidative transformations of ascorbate (AH^-). The ratio A^• content/AH^- content (A^• /AH^-) has been widely used as an interesting tool to estimate mild to moderate oxidative transformations, providing a quick and simple method of diagnosis of stress in the hydrophilic cellular medium. The aim of this work was to summarize studies on the cellular oxidative condition in algae and invertebrates by assessing the A^• /AH^- ratio under environmentally changing conditions. The use of indices of oxidative stress increasingly sensitive and, somewhat more specific, can bring a new light to the still unknown world of oxidative responses in marine organisms     

基于AQUATOX模型的入湖河道富营养化模拟研究

针对目前入湖河流污染负荷高、富营养化严重等问题,以殷村港为例,基于2014年殷村港每月实测数据,借助AQUATOX水生态模型软件进行建模,并在模型率定、验证后对其水环境进行敏感性分析及控制、非控制模拟,分析了营养盐、温度、流速等因子对殷村港富营养化水平的影响。结果表明,同是控制削减20%浓度下,控磷比控氮更有利于抑制殷村港藻类生长,20%TP的削减可使殷村港叶绿素a浓度削减量达33%,另外在削减磷含量的同时适当增大氮浓度以增大氮磷比可更好抑制藻类生长;水温降低15%,藻类总量有所增加,但蓝藻显著减少,夏季削减量最高达20%以上;流速增大15%时,蓝藻的生物量削减在15%左右,而绿藻、硅藻生物量增多。因此,修建沿河生态护岸、河湖水系连通等可利于改善入湖河道的富营养化状态。     

Novel anticoagulant compound from fermented red alga <Emphasis Type="Italic">Pachymeniopsis elliptica</Emphasis>

Natural fermentation was tested as a method of releasing active compounds during screening for potential anticoagulant activity in three types of algae (Pachymeniopsis elliptica, Sargassum horneri, and Ulva pertusa). Freeze dried algae samples (2.5 g) were fermented by adding 75 g of sugar and 500 mL of water and thereafter kept at room temperature (25 °C) for 3 months. Activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were measured every 2 weeks for 3 months to determine the optimum time for the highest activity. Fermented P. elliptica, (which had the highest activity) was subjected to anion exchange chromatography (DEAE-cellulose) and sepharose 4B gel permeation chromatography. The purified sample was analyzed by agarose-gel electrophoresis and polyacrylamide gel electrophoresis (PAGE) to confirm the purification and to determine the molecular mass, respectively. The 360 μg/mL of purified compound (Mwt > 500,000 Da) had both APTT and PT activities (>1,000 s). However, at the concentrations of 180 μg/mL, purified compound and heparin showed 540 and >1,000 s APTT activity, respectively. Though, the purified compound of P. elliptica considered as a weaker anticoagulant than heparin, this purified anticoagulant polysaccharide could be considered as a good alternative source as an anticoagulant. Moreover, the technique of fermentation is an inexpensive and feasible, this purified anticoagulant polysaccharide compound could be used in pharmaceutical and biomedical industry. Further investigations need to be performed to determine the mechanism of this novel anticoagulant compound. The authors Prashani Mudika Ekanayake and Chamilani Nikapitiya contributed equally to this work.     

Effects of nutrient deprivation on biochemical compositions and photo-hydrogen production of Tetraselmis subcordiformis

Tetraselmis subcordiformis (formerly called Platymonas subcordiformis), a marine green alga, was previously demonstrated to photo-biologically produce hydrogen when treated with CCCP (Carbonyl Cyanide m-Chlorophenylhydrazone). The current results of our studies showed that there was a peak yield of hydrogen by T. subcordiformis at the stationary stage of its algal growth curve, suggesting that starvation of an essential element induced biochemical changes that enhanced hydrogen production by T. subcordiformis. Further investigation indicated that among nitrogen, sulphur and phosphorus (which are major components in the cultivation medium), nitrogen deprivation in the medium reduced the protein content inside the cells of T. subcordiformis, but increased the carbohydrate content over 4 times, resulting in 5.5 times increase in the hydrogen yield.     

固相微萃取-气相色谱串联两级质谱法测定水中10种藻类代谢产物

文中建立了固相微萃取-气相色谱串联两级质谱法测定地表水中的10种藻类代谢产物的含量,研究了萃取时间、萃取温度、萃取剂量、萃取纤维等预处理参数对嗅味物质含量的影响,同时对不同规格的色谱柱进行分离效果比较.结果表明,在萃取时间为25 min、萃取温度为65℃、氯化钠含量为1.7 g的测定条件下,采用50/30μm DVB/...     

高锰酸钾预氧化及预氯化处理滦河水的研究

该研究从高锰酸钾的衰减速度着手,综合剩余高锰酸钾浓度、气浮和过滤后出水浊度来确定高锰酸钾最佳投量范围为0．7～1．3mg／L。比较了预氯化和高锰酸钾预氧化对出水水质及后续工艺的影响。     

15%CO2胁迫下雨生红球藻积累油脂制生物柴油

采用经60Co-γ射线核辐射诱变和15%CO2驯化后的雨生红球藻突变藻株为对象,研究15%CO2对雨生红球藻制备生物柴油潜力的影响。结果表明:随着高光照和15%CO2协同胁迫时间的延长,油脂合成相关乙酰辅酶a羧化酶、β-酮酰基-ACP缩合酶Ⅲ和二酰基甘油酰基转移酶相对表达量分别提高至初始水平的1.2、1.4和1.3倍。15%CO2胁迫下雨生红球藻饱和油脂含量由2%CO2条件下的33.0%升至35.2%。15%CO2胁迫下雨生红球藻细胞孔径增大15%,孔面积增加2.3倍。萃取虾青素后的雨生红球藻渣亲水性指数为4.98,高于未处理生物质的亲水性指数。差示扫描量热分析(DSC)结果表明,藻渣制备的生物柴油的结晶度和熔点分别为-1.3℃和6.1℃。     

Hydrogen production from dry spirulina algae with downstream feeding in microwave plasma reactor assisted under atmospheric pressure

Advancement in the field of biomass and bioenergy has pulled in researchers to produce biofuels derived from naturally accessible feedstock by adopting diverse innovative approaches in biomass pretreatment. In this study, pyrolysis of micro algae with downstream processing of biomass from the resonator cavity under atmospheric pressure was conducted and hydrogen production produced under different microwave power was analyzed. With the increase in microwave power, the hydrogen gas yield accounted to be as twice as that at lower power, where the concentration of produced hydrogen accounts for about 30.80%, 33.20%, and 37.58% at microwave power levels of 800, 900 and 1000 W. It was also observed that no methane was produced in this study since most of the methane produced from microwave plasma conversion has reacted with CO₂ and produced CO and H₂, hence dropped in the concentration of CO₂ with decline in power intensity.     

褐藻多酚对晚期糖基化终产物的抑制作用研究

目的 研究褐藻多酚对晚期糖基化终产物(advanced glycation end products,AGEs)生成的抑制作用及其机制.方法 建立牛血清蛋白与葡萄糖体外模拟体系及食品热加工鱼肉肠模型,以不同浓度褐藻多酚为抑制剂,研究其对AGEs生成的抑制作用;通过分析模拟体系中赖氨酸和葡萄糖含量、蛋白质巯基水平及葡萄糖...     

Factors affecting Cladophora growth in the eastern basin of Lake Erie: Analysis of a monitoring dataset (2012–2019)

Cladophora is a naturally occurring benthic alga in the Great Lakes which can reach nuisance levels in the nearshore, leading to beach closures and other impacts. A monitoring program was initiated in 2012 in the eastern basin of Lake Erie to identify ecological factors driving its growth. Inflows from the Grand River, the largest river to the north shore, were generally positively associated with phosphorus concentrations in the nearshore and negatively associated with light reaching the lakebed. At the depths sampled (3 m–18 m), Cladophora was strongly influenced by light availability, and due to shading by the Grand River plume, an overall negative association was found between Cladophora biomass and phosphorus inputs. Phosphorus limitation was only observed at shallow sites farthest from the Grand River. Positive associations between dreissenid mussel coverage and both Cladophora biomass and tissue phosphorus suggest that nutrient cycling by dreissenids supports Cladophora growth. Our results indicate that i.) the Grand River has a strong influence on nearshore nutrient levels and water clarity; and ii.) Cladophora is limited by both phosphorus and light to varying degrees within the study area, although light appears to be the dominant factor, at least at these depths, years, and locations. The implication that phosphorus reductions could lead to increased Cladophora biomass by improving light conditions will need to be considered carefully against the known historical success of controlling nuisance algae through nutrient management.