Potential biodiesel-producing microalgae: two new strains of Amphikrikos sp.

BH32 and BH43 were isolated and identified as Amphikrikos sp. based on morphological characteristics and phylogenetic trees. They shared the same 18S rRNA sequences, but possessed different amounts of introns in their 18S rDNAs. The specific growth rate, cellular component and fatty acid profile under different growth stages have been surveyed. Their main fatty acids were found to be C16 and C18 groups. Our results indicated that both of them could be taken as excellent candidates of biodiesel. Moreover, the intra-genus polymorphism of 18S rDNA caused by intron presence/absence can provide valuable information for the study of intron evolution.     

Determination of the mechanism of photoinduced toxicity of selected metal oxide nanoparticles (ZnO, CuO, Co3O4 and TiO2) to E. coli bacteria

Cytotoxicity of selected metal oxide nanoparticles(MNPs)(ZnO,CuO,Co 3 O 4 and TiO 2)was investigated in Escherichia coli both under light and dark conditions.Cytotoxicity experiments were conducted with spread plate counting and the LC 50 values were calculated.We determined the mechanism of toxicity via measurements of oxidative stress,reduced glutathione,lipid peroxidation,and metal ions.The overall ranking of the LC 50 values was in the order of ZnO < CuO < Co 3 O 4 < TiO 2 under dark condition and ZnO < CuO < TiO 2 < Co 3 O 4 under light condition.ZnO MNPs were the most toxic among the tested nanoparticles.Our results indicate depletion of reduced glutathione level and elevation of malondialdehyde level correlated with the increase in oxidative stress.Released metal ions were found to have partial effect on the toxicity of MNPs to E.coli.In summary,the dynamic interactions of multiple mechanisms lead to the toxicity of the tested MNPs to E.coli.     

白洋淀多种生境沉积物有机质来源解析及其演变

沉积物有机质来源及其演变的解析对富营养化湖泊的防治及生态修复具有重要的意义.白洋淀是华北地区最大的淡水湖泊,由于受人类活动的影响,其生境逐渐破碎化且不同生境的有机质来源及演变过程尚不清楚.通过对白洋淀河道、湖面、鱼塘、荷塘4种不同生境沉积物岩芯正构烷烃含量与组成特征的分析,结合主成分分析-多元线性回归(PCA-MLR)模型,以解析其有机质的来源及演变.结果表明：由于受不同人类活动的影响,不同生境沉积物的有机质来源不同.鱼塘和荷塘沉积物有机质来源以藻类等水生低等生物为主,分别达到78.3%、72.7%;河道沉积物有机质来源则以陆生高等植物为主,占比为63.8%;开阔湖面沉积物中不同有机质来源所占比例分别为水生低等生物33.0%,水生高等植物26.2%,陆生高等植物40.8%.该结果与白洋淀地区人类活动变化与经济社会发展历程相对应.值得注意的是,尽管随着雄安新区一系列环境治理措施和环保工程的实施,白洋淀水质恶化趋势得到遏制,藻类等水生低等生物在河道和湖面的沉积物有机质来源占比开始缓慢降低,但是由于水体富营养化程度较深且藻类死亡后仍大量沉积于沉积物中,鱼塘和荷塘沉积物有机质来源中水生低等生物...     

国内外废弃油脂的处理情况及利用方式概述

介绍了国内外废油脂的产生及回收利用现状,研究了废油脂不同的处理利用技术,并重点分析了生物柴油技术的制备应用。     

采用尼罗红荧光探针对微藻中油脂的定量测定

以尼罗红为荧光探针,对小球藻油脂含量的定量分析条件进行了研究.测定中,使用48孔酶标仪作为荧光检测器.研究显示,当荧光激发光波长为485 nm,发射光波长为580 nm时,适用于测定微藻中的中性油脂含量.当二甲基亚砜终浓度为20%,尼罗红终浓度为0.5μg.mL-1,藻液与尼罗红置于40℃暗处反应5 min后,能够获得最大的相对荧光测定值.当藻液光密度OD680在0.61至1.73时,藻液油脂含量与尼罗红荧光测定值呈现良好的线性关系,相关系数R2为0.9836,可以通过尼罗红荧光值的测定推算油脂的含量.     

Rice seedlings under cadmium stress: effect of silicon on growth,cadmium uptake,oxidative stress,antioxidant capacity and root and leaf structures

In this study, the effect of silicon (Si) addition on cadmium (Cd) toxicity in rice seedlings was investigated. After a series of screening experiments, 50 μmol·L^?1 of Cd and 10 μ mol·L^?1 of Si were selected. Treatment of rice seedlings with Cd (50 μ mol·L^?1) resulted in significant accumulation of this metal in roots and shoots. The data revealed that accumulation of Cd resulted in oxidative stress in rice seedlings as evidenced by increased accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA; a peroxidation product of lipids). However, addition of Si (10 μ mol·L^?1) together with Cd prevented accumulation of Cd, H₂O₂ and MDA. Antioxidant capacity was decreased by Cd but enhanced by Si addition. Cd decreased the length and frequency of root hairs, stomatal frequency, and distorted leaf mesophyll cells and vascular bundles. However, addition of Si together with Cd reduced these abnormalities. The results showed that addition of exogenous Si protected rice seedlings against Cd toxicity by preventing Cd accumulation and oxidative stress (H₂O₂ and MDA accumulation) by increasing Si accumulation and antioxidant capacity, which maintained the structure and integrity of leaf and root.     

Studies on the water extracts of medicinal plants grown in copper mining areas and their antioxidant effects

High copper (Cu) accumulation in medicinal plants might favor lipid peroxidation and hence affect antioxidant responses. This effect was studied by determining antioxidant activities in the water extracts of medicinal plants from Cu mining impact site and compared with control samples. Antioxidant activities of the extracted medicinal plants were assayed by measuring (1) total phenolic and flavonoid contents, (2) diphenyl-1-picrylhydrazyl (DPPH)^? free radical scavenging activity, and (3) inhibition capacities of lipid peroxidation. The total phenolic as well as total flavonoid contents of the mining impact samples and control samples are not significantly different. However, inhibition of lipid peroxidation capacities was significantly less (12–60%) for mining impact samples as reflected by the IC₅₀ values. These anomalies were attributed to high concentrations of Cu (2–4-fold higher) in mining impact samples as measured by inductively coupled plasma mass spectrometry. A positive correlation was observed between Cu levels and IC₅₀ values for the inhibition of lipid peroxidation for mining impact samples.     

Influence of marine alga against mercury-induced biochemical changes,structural destabilization,and genotoxicity in marine tiger fish,Therapon jarbua

This study elucidated the protective role of alga against mercury (Hg)-induced toxicity in marine fish. Bath immersion with mercury chloride (HgCl) [0.125 and 0.25?ppm] in combination with the algal extract (3?ppm) to Therapon jarbua offered a significant protection against Hg only induced disturbed liver function, damaged histoarchitecture, elevated oxidative stress, and DNA fragmentation of tissues. Mercury exposure decreased hepatic superoxide dismutase (SOD), catalase (CAT) activities, and the level of nonprotein-soluble thiol (NPSH, GSH), with a concomitant increase in thiobarbituric acid reactive substances (TBARS) in the gill, kidneys, liver, and blood. Algal supplementation diminished the rise in TBARS restoring CAT, SOD, and GSH levels to control. Reduced generation of free radicals may be correlated to protect DNA stability and morphology. This study indicates the ability of alga to ameliorate Hg-mediated injuries. In conclusion, Kappaphycus alvarezii extract did not show any toxicity and its safety is suggestive for using as a supplement in fish food.     

Plasma lipid profiles and risk of cardiovascular disease on occupational exposure in Karimnagar

Occupational exposure is unregulated in developing countries like India, and becoming the most common cause of disease of environmental origin. The present study was aimed to investigate the effects of occupational exposure on plasma lipid profiles, and risk of cardiovascular diseases. A total of 79 human volunteers were included in the study. Control subjects were healthy housewives of Karimnagar, India. Occupationally exposed individuals included different occupational workers like petrol station attendants, battery chargers, drivers, welders, pesticide-exposed workers, painters, and auto mechanics. These subjects were shown to be chronic occupationally-exposed for at least three years, and neither associated with any other chronic pathological conditions like hypertension or diabetes, nor under any medication other than analgesics during the month preceding the study. Subjects with excessive high or low caloric intake were excluded from the study. Total cholesterol (TC), LDL cholesterol, triglycerides (TG), VLDL cholesterol, LDL/HDL cholesterol, and TC/HDL ratio in these subjects were significantly higher than those in control subjects, whereas HDL cholesterol was not markedly affected. Blood pressure (systolic and diastolic), and other anthropometric parameters (body mass index (BMI), body fat index (BFI), body surface area (BSA)) were not significantly different between groups. Data suggest that chronic occupational exposure increases plasma lipid levels and is thereby associated with cardiovascular complications.     

不同碳源种类对好氧颗粒污泥合成PHA的影响

影响好氧颗粒污泥稳定性的因素众多,其中碳源种类的不同会造成好氧颗粒污泥合成聚羟基烷酸酯(PHA)的不同,进而影响其稳定性能.采用混合碳源驯化培养的好氧颗粒污泥进行试验.考察了厌氧条件下,乙酸钠等八种碳源对好氧颗粒污泥合成PHA的影响.结果表明,颗粒污泥对乙酸钠和蔗糖具有较好的转化能力,合成PHA的量分别为102.19mgCOD/g·VSS和70.58mgCOD/g·VSS,显著高于其他碳源的PHA合成量(5~26mg/g×VSS).故以蔗糖和乙酸钠作碳源均有利于颗粒污泥稳定性能的维持,而当以甲醇作碳源时好氧颗粒污泥的贮存能力最差.