Detection of dioxygenase genes present in various activated sludge

GOAL, SCOPE AND BACKGROUND: Activated sludge from refineries contains various microorganisms that could utilize aromatics under aerobic conditions due to the oxygenase enzymes. Dioxygenase enzymes are oxygenases, which are involved in the ring cleavage step of aromatic hydrocarbons. In this study, the selected catabolic loci involved in ring cleavage have been monitored in the activated sludge samples at different time intervals. The investigation of the dioxygenase genes in the Effluent Treatment Plants (ETPs) and evaluation of their presence at different time points provides a clue for the aromatic utilizing potential of the inherent microbial flora. METHODS: The catabolic gene loci pheB, xylE, tod-isp, bed and nahG responsible for the enzymes catechol 1,2-dioxygenase, catechol 2,3-dioxygenase, toluene dioxygenase-iron-sulphur protein component, benzene dioxygenase and naphthalene dioxygenase were used respectively. The time dependent change in eubacterial population was demonstrated by the amplification of 16S rDNA product, followed by restriction digestion. The template DNA was obtained from the activated sludge collected from ETPs. The supporting physiological data for the overall performance of sludge was developed using respirometric analysis. The on-site COD and MLSS analysis for ETP was used in final evaluation. The study was carried out with samples collected from three different ETPs and also from a selected ETP at different time intervals. RESULTS AND DISCUSSION: The respirometric studies were carried out with phenol, catechol, toluene, and naphthalene to arrive at the target genotypes for further study by PCR protocol. The respirometric analysis coupled with the COD and MLSS analysis represented the physiological capacity of the various sludges. Initially, the tracking protocol was optimized by using different sludge samples, which were collected from refineries. The selected genotypes were amplified and their presence has been confirmed using Southern analysis. The gene loci tod-isp, bed and xylE were commonly observed at various time intervals of the sludge from the same source. The gene loci pheB and nahG were found to be relatively rare. CONCLUSION: The 16S rDNA PCR products after restriction digestion produced different DNA fingerprint patterns, suggesting that the microbial community composition was diverse in the three sources. Similarly, the presence of the catechol 2,3-dioxygenase, benzene dioxygenase and toluene dioxygenase genes confirmed the aromatic degrading potential in the various sludges. The probes could not pick the nahG and pheB genes. However, the respirometeric assay suggested that the oxidative capacity to use naphthalene as a substrate exists. RECOMMENDATION AND PERSPECTIVE: Our study of the diversity at various time points from the ETP provided an overview of the shifts of the catabolic composition of the sludge. This also depends on the influential parameters like the incoming pollutant level and the environmental conditions that are prevailing and often changing from time to time. The results of direct DNA extraction and PCR amplification do reflect the relative abundance of a particular catabolic genotype, which could be used to monitor the efficiency of treatment.     

Factors Associated with Alien Plants Transitioning from Casual, to Naturalized, to Invasive

Abstract:  To explain current plant invasions, or predict future ones, more knowledge on which factors increase the probability of alien species becoming naturalized and subsequently invasive is needed. We created a database of the alien plants in seminatural habitats in Ireland that included data on taxonomy, invasive status, invasion history, distribution, and biological and ecological plant characteristics. We used information from this database to determine the importance of these factors in increasing the ability of species to become naturalized and invasive. More specifically, we used two multiple logistic regressions to identify factors that distinguish naturalized from casual alien plant species and invasive from noninvasive, naturalized alien species. Clonal growth, moisture-indicator value, nitrogen-indicator value, native range, and date of first record affected (in order of decreasing importance) the probability of naturalization. Factors that distinguished invasive from noninvasive species were ornamental introduction, hermaphrodite flowers, pollination mode, being invasive elsewhere, onset of flowering season, moisture-indicator value, native range, and date of first record. Incorporation of phylogenetic information had little influence on the results, suggesting that the capacity of alien species to naturalize and become invasive evolved largely independently in several phylogenetic lineages. Whereas some of the variables were important for both transitions, others were only important for naturalization or for invasion. This emphasizes the importance of studying different stages of the invasion process when looking for mechanisms of becoming a successful invasive plant, instead of simply comparing invasive with noninvasive alien species. Our results also suggest that a combination of species traits and other variables is likely to produce the most accurate prediction of invasions.     

Population Biology of Gametophytes in Homosporous Polypodiophyta

Modern data on the diversity of morphology and morphogenesis of gametophytes in homosporous ferns, their vegetative reproduction, and the existence of their colonies growing separately, independently of sporophytes, are reviewed. The ontogenetic states of gametophytes are identified and characterized. The problem of gametophyte chemical interactions mediated by antheridiogen, an exohormone, is discussed. These intrapopulation interactions determine the polyvariant character of gametophyte ontogeny and the complex age and sex structure of their colonies.     

污水处理厂中雄激素分布及行为的研究进展

人类及生物体内在自然代谢及药物使用过程中产生的甾醇类激素如果在污水处理厂中未能完全去除或是未加处理直接排放,则会污染受纳水体,并对其中的鱼类等生物造成影响,其中人体内产生的雄激素睾酮的浓度比雌激素雌二醇要高1~3个数量级.本文比较了当前各地污水处理厂中的雄激素分布,阐述了污水处理工艺对雄激素的去除效果;其中,格栅、初沉池等初级处理工艺基本不去除雄激素;厌氧-缺氧-好氧等二级处理工艺通过生物降解等作用可以有效去除80%~100%的雄激素;氯消毒、臭氧等三级处理工艺对雄激素的去除效率相差较大,在-66.7%~70%范围内波动;同时也对去除雄激素的新型材料研究及未来研究方向进行了展望.     

澎溪河消落带典型植物群落根际土壤无机氮形态及氮转化酶活性

三峡库区消落带是典型的生态脆弱带,其土壤N循环因受到植物根际效应和季节性淹水的影响而具有特殊性.本研究以三峡库区一级支流澎溪河消落带为例,选择4种植被(狗牙根、香附子、苍耳以及玉米)覆盖区,采集植物根际、非根际土壤,分析根际土壤与非根际土壤理化性质、无机氮形态以及7种N素转化相关酶,并比较了4种植物根际效应强度,以反映不同植物覆盖对消落带土壤N循环过程的影响.研究表明:供试植物根际土壤pH值均低于非根际,有机质、全氮、全磷含量均高于非根际,表明植物根际对消落带土壤养分有富集作用;4种植物根际土壤硝态氮、铵态氮、亚硝态氮及14d可矿化氮含量均高于非根际,且土壤硝态氮、亚硝态氮以及14d可矿化氮含量呈现香附子＞狗牙根＞苍耳/玉米;总体上根际土壤N转化酶活性高于非根际,且狗牙根和香附子覆盖区脲酶、亚硝酸还原酶、谷氨酰胺酶、脱氢酶显著高于玉米和苍耳覆盖区;蛋白酶、脲酶、谷氨酰胺酶活性与4种N形态均呈显著相关性,是消落带土壤N转化的主要参与酶类;根际效应分析结果香附子和狗牙根对消落带土壤N转化的根际效应强度大于苍耳和玉米,有利于土壤N素的固定和保持.植物根际效应对消落带土壤N素循环的影响可为消落带植被恢复工程中植被选择提供参考,也为改善消落带土壤退化相关研究提供科学支撑.     

利用文蛤生物标志物评价尾水-海水混合体系污染水平

采用不同浓度（体积比0%～40%,经天然海水稀释而成）的市政污水处理厂（MSTP）尾水对文蛤（Meretrix meretrix）连续培养9d,通过测定9种生化因子水平评价污染暴露对双壳类的生物学效应包括：内脏中的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GPx）、谷胱甘肽还原酶（GR）、谷胱甘肽（GSH）、乙酰胆碱酯酶（AChE）、金属硫蛋白（MTs）、硫代巴比妥酸反应物（TBARs）以及血细胞的溶酶体膜稳定性（LMS）.SOD、CAT除外的所有生化因子均能对尾水污染产生敏感响应,其中,GPx、MTs、AChE和LMS的响应与尾水浓度呈显著相关（P<0.05或P<0.01）,适于作为尾水污染的生物标志物;依据这些生物标志物计算的综合生物标志物响应指数值（IBR_v2=0.61～2.65）随尾水浓度上升而增大,且两者间存在显著相关性（P<0.01）.研究结果表明,基于生物标志物响应值计算IBR指数的方法适于MSTPs尾水-海水混合体系的综合污染评价.     

Phytoextraction of lead and its relationship with histidine in six plant species using ICP-MS and HPLC-MS

High-performance liquid chromatography-mass spectrometry and inductively coupled plasma mass spectrometer (ICP-MS) methods were used for determination of histidine and lead in leaves of six plant species taken from industrial areas, including Gaziantep and Bursa cities, Turkey. For extraction of histidine from plant samples, ultrapure water was used at 90°C for 30?min. Using optimum conditions of 0.2?mL?min^?1, 70?V, 15?µL and 20°C, concentrations of histidine (in mg?kg^?1) were found to be between 2 and 9 for Morus L., 6 and 13 for Robinia pseudoacacio L., 2 and 10 for Populous nigra L., 3 and 10 for Thuja, 1 and 11 for Cupressus arizonica and 4 for Cedrus libani. Concentrations of lead were in the ranges of 4–378?mg?kg^?1 for Morus L., 1–122?mg?kg^?1 for R. pseudoacacio L., 1–14?mg?kg^?1 for P. nigra L., 1.6–224?mg?kg^?1 for Thuja (Cupressaceae), 1.5–57?mg?kg^?1 for C. arizonica and 1.8?mg?kg^?1 for C. libani. Related with correlation coefficient, significant linear correlation for Thuja (Cupressaceae) (r?=?0.81) and insignificant linear correlation for P. nigra L. (r?=?0.50) were seen. Further, the leaves of Morus L., Thuja and R. pseudoacacio L. have a potential as biomonitor and/or hyperaccumulator for Pb because the rates of their maximum/minimum concentrations were found higher than 90.     

洱海湖滨带挺水植物残体腐解特征及其环境效应初探

采用试验模拟的方法,研究洱海4种主要挺水植物茭草(Zizania caduciflora)、香蒲(Typha latifolia)、水葱(Scirpus validus)和芦苇(Phragnites australis)在水体中的腐解特征. 结果表明:在21 d的腐解试验中,水葱腐解速率最快,茭草和香蒲其次,芦苇最慢; 挺水植物单位干物质TN释放量表现为水葱>茭草≈香蒲>芦苇,TP释放量表现为水葱>茭草>香蒲>芦苇; 4种植物TP释放率均高于TN,腐解出的TP进入水体的比例也明显高于TN. 水体中ρ(TN),ρ(TP)及ρ(COD_Cr)均在腐解初期(1～3 d)快速上升,pH和ρ(DO)快速下降; 随后,ρ(TN),ρ(TP)及ρ(COD_Cr)均缓慢下降,pH和ρ(DO)则缓慢回升. 结合洱海湖滨带挺水植物空间分布的调查结果,估算全湖湖滨带4种挺水植物中TN和TP的总质量分别为17.622和2.870 t,其中茭草和香蒲中的TN和TP分别占91%和95%,对茭草和香蒲进行适时、适宜的收割对改善湖滨带的水质具有重要的意义.      

A Global Outlook to the Carbon Dioxide Emissions in the World and Emission Factors of the Thermal Power Plants in Turkey

World primary energy demand increases with increases in population and economic development. Within the last 25 yr, the total energy consumption has almost doubled. For the purpose of meeting this demand, fossil energy sources are used and various pollutants are generated. CO₂ is also one of these gases, which cannot be removed like other pollutants, and it causes greenhouse effect and climate change. Reducing the CO₂ emission is very important because of the environmental concerns and regulations, especially the Kyoto Protocol. This paper reviews the estimated world carbon emissions, Turkey's situation in electrical energy production, emission amounts estimated until the year 2020 and emission factors for dust, SO₂, NO_x and CO₂. The estimated results show that CO₂ emissions from thermal power plants in Turkey will make about 0.66 % of the global CO₂ emissions in 2020.     

神农架国家级自然保护区樟科资源植物分析

神农架樟科植物种类共有 7属 3 1种 (含变种 ) ,资源植物十分丰富 ,按其用途可分为观赏植物类、蜜源植物类、药用植物类、木材植物类、香料植物类、工业用油脂植物类及珍稀保护植物类等。这些资源植物具有较大的开发利用价值。