Institute of Hydrobiology, Chinese Academy Of Sciences
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Morphological description of Opalina obtrigonoidea Metcalf, 1923 (Heterokonta, Opalinea) from Duttaphrynus melanostictus and evaluation of the ITS region as a suitable genetic marker for inter-species identification in Opalina
No full textThe redescription of Opalina obtrigonoidea Metcalf, 1923, collected from the rectum of the toads Duttaphrynus melanostictus, is presented in this paper based on detailed morphological information and molecular data. Our results revealed that O. obtrigonoidea varies greatly in body dimensions. Its morphological characteristics allow its differentiation from Opalina undulata. Surprisingly, we sequenced its SSU rDNA-ITS1-5.8S rDNA-ITS2-LSU rDNA (5' end) and found the SSU rDNA of O. obtrigonoidea is nearly identical to that of O. undulata. However, there are differences in both the ITS1 and ITS2 regions that allow their distinction and confirm the morphological differences. Our results indicate that O. obtrigonoidea and O. undulata are closely related species in which morphological and genetic markers have evolved at different speeds. Due to this, the SSU rDNA gene may not be a valid marker for inter-species identification in Opalina, but the ITS is a valid marker for differentiating species in this genus
Adsorptive removal of anionic dyes by graphene impregnated with MnO2 from aqueous solution
No full textGraphene nanosheet-manganese dioxide (GN-MnO2) composite was synthesized by a microwave-assisted method. The physico-chemical properties of modified graphene (GN) were characterized by different techniques, such as scanning electron microscopes (SEM), Fourier-transform infrared spectrometers (FTIR), X-ray diffraction (XRD) and Raman spectroscopy. The effects of contact time, pH, concentration, temperature, and the dose of adsorbent on the adsorption attributes of Congo red (CR) and Acid green 25 (AG25) on GN-MnO2 composite was studied. The experimental facts of the isotherm were found to be more fitted with the Langmuir isotherm rather than the Freundlich one, while the pseudo-second-order kinetic model/curve was found to be fitted with experimental data, giving an indication that the experiment was controlled by chemical processes. The maximum adsorption capacities is derived from the Langmuir model equation at 303 K were 270.06 and 324.26 mg/g for CR and AG25, respectively. The thermodynamic study revealed that the adsorption of CR and AG25 dyes onto the GN-MnO2 was pretty much spontaneous in nature and showed that the GN-MnO2 was a decent adsorbent for the elimination of CR and AG25 ions in aqueous conditions. The column studies were conducted in varying flowrates (4-12 mL/min), and bed heights (0.5-1.5 cm), with a concentration of 100 mg/L, while at pH of 3 and 4 for CR and AG25, respectively. The adsorption capability increased with the increasing influent level and column depth while it was reduced by upturn in flow-rate. The results obtained were fitted well with the Bed Depth Service Time BDST and Thomas models
Screening High CO2-Tolerant Oleaginous Microalgae from Genera Desmodesmus and Scenedesmus
No full textMicroalgae from genus Scenedesmus sensu lato (including Desmodesmus and Scenedesmus) were reported to be particularly suitable candidates for CO2 biomitigation. In this study, 16 strains from Scenedesmus sensu lato were obtained from different climate zones of China and their phylogenetic positions were determined. Seven strains out of the 16 showed high CO2 tolerance and grew much faster under 20% CO2 than air condition. Two representatives from genera Desmodesmus (NMD46) and Scenedesmus (HBX310) respectively were selected due to their higher lipid productivity, and the maximum value of 146 mg L-1 day(-1) was achieved in NMD46. Triacylglycerols increased with the rising of CO2 levels from 0.04 to 15% in NMD46, while they changed little in HBX310. High CO2 level decreased the polyunsaturated fatty acid content in NMD46 but increased it in HBX310. NMD46 is more suitable for standardized biodiesel production in view of its lipid and fatty acid composition responses to high CO2
南洞庭湖区软体动物物种多样性评估及保护对策
No full text洞庭湖孕育和维持了较高和独特的软体动物多样性。尽管有关该湖软体动物的调查较多,但多分散于各文献中。本文结合文献调研和现场调查(2013–2018年),系统评估了南洞庭湖区软体动物物种多样性,解析驱动群落格局演变的关键因子,并提出合理的保护对策。共记录2纲5目14科33属87种(腹足纲41种,双壳纲46种),其中本调查记录54种,隶属于2纲5目12科31属,包括腹足纲22种,双壳纲32种。评估结果显示处于近危和受威胁等级物种21种,包括腹足纲4种和双壳纲17种。调查区域软体动物平均密度和生物量分别为173.1 ind./m~2和279.3 g/m~2。优势种为河蚬(Corbicula fluminea)、大沼螺(Parafossarulus eximius)、铜锈环棱螺(Bellamya aeruginosa)、卵河螺(Rivularia ovum)。基于距离的冗余分析(distance-based redundancy analysis, dbRDA)结果显示,局域环境因子(底质类型、水深、 pH、总溶解固体和总磷)制约软体动物的群落变异。另外,区域内的人类活动(如商业采砂、建坝和沿岸土地利用、过度捕捞和非法电捕等)亦深刻影响软体动物的生存。这些人类干扰已导致软体动物物种多样性显著下降,可能造成一些特有物种的局域性灭绝。为了恢复和保护软体动物物种多样性和资源,应采取一系列对策,包括管控合法的挖沙业和取缔非法挖沙业、禁止过度捕捞和非法电捕、维持水文的自然节律、恢复沿岸自然湖滨带和控制点源和面源污染物排入等。我们呼吁尽快在南洞庭湖区建立软体动物国家级自然保护区,以保护该湖区(可能是整个洞庭湖)残存的软体动物物种多样性和特有性
Development and characterization of EST-SSR markers for the endangered tree Magnolia patungensis (Magnoliaceae)
No full textMagnolia patungensis (Magnoliaceae) is an endangered tree species endemic to China. To facilitate analysis of its genetic variability, we developed novel polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers using transcriptome data. In total, 37 774 SSRs amounting to 91.52 Mb were identified from 131 132 unigenes, with the frequency of 28.81% and the average density of 2.42 kb. Mononucleotide (50.81%) and dinucleotide (34.12%) were the most abundant repeat types. We randomly selected 102 putative loci to test the amplification efficiency and the degree of polymorphism using three populations from which 15 individuals per population were sampled. The successful amplification rate was 36.27% and the polymorphism rate 12.75%. The 13 polymorphic SSR marker primers selected were used to characterize the genetic diversity of M. patungensis. A total of 40 alleles were identified for the species, ranging from 2 to 5 per locus. At the population level, the mean number of alleles per locus ranged from 1.9 to 2.5. and the mean observed and expected heterozygosity values from 0.308 to 0.446 and 0.304 to 0.424. respectively. Significant genetic differentiation (F-ST = 0.286) and low gene flow (N-m = 0.627) among populations were discovered. Transferability of the markers was tested in five congeneric species. Nine loci were successfully amplified in M. dandyi, eight in M. insignis, M. fordiana and M. hookeri, and seven in M. conifera. These new EST-SSR markers will be an essential tool for the conservation of this endangered species as well as for investigating the evolutionary history forts. patungensis and its congenerics
Comprehensive transcriptome analyses of two Oocystis algae provide insights into the adaptation to Qinghai-Tibet Plateau
No full textThe harsh environments and high biodiversity of the Qinghai-Tibet Plateau (QTP) provide an ideal natural laboratory for studies on adaptive evolution. Low temperature and intense UV-B radiation are the main abiotic stresses to plants at high altitudes. The rapid development of RNA sequencing has enabled us to investigate the molecular adaptations of plants that thrive in the QTP at the genomic level. Despite the ecological importance of Oocystis algae on the plateau, the genetic mechanisms of the adaptations of these algae to this high-altitude environment remain poorly understood. Here, we sequenced and assembled the transcriptomes of Oocystis marina and Oocystis sp. LXD-20, and undertook comparative transcriptomic and evolutionary analyses to reveal their adaptive strategies. Our results identified 348 positively selected genes in Oocystis algae, and functional analyses indicated that many of these positively selected genes were associated with adaptation to abiotic stresses, such as antioxidative response, DNA repair mechanisms, translation, and post-translational modifications. We also identified the cold-responsive and UV-B-responsive genes in O. marina and Oocystis sp. LXD-20, and revealed the transcriptional regulation strategies under stress conditions. Our analyses provided a wealth of sequence data to serve as reference transcriptomes for future studies, and shed light on the adaptive strategies of green algae that live in the QTP
The potential persistence of abundant submerged macrophyte and phytoplankton in a shallow system at very high nutrients loading: results from a mesocosm study
No full textShallow lakes are typically either in a clear water state with high abundance of submerged macrophytes or in a turbid state dominated by phytoplankton. A 10-week mesocosm experiment was set up to test the hypothesis that in a very shallow aquatic ecosystem impacted by very high nutrient loading, both submerged macrophytes and phytoplankton may be abundant. Nutrient levels, phytoplankton biomass (measured as chlorophyll a, Chl a), total suspended solids (TSS), inorganic suspended solids (ISS), and submerged macrophyte biomass were measured in three different treatments: DH (deep (1 m) water with very high nutrient loading), SH (very shallow (0.5 m) water with very high nutrient loading), and SL (very shallow (0.5 m) water with low nutrient loading). Of the three treatments, the DH mesocosms exhibited the highest nutrient, the TSS and ISS levels, the highest phytoplankton biomass, and the lowest submerged macrophyte biomass, while the lowest nutrient, the TSS and ISS levels, the lowest phytoplankton biomass, and the highest submerged macrophyte biomass were observed in the SL treatment. All measured parameters exhibited intermediate levels in the SH treatment. Our study demonstrates that in very shallow aquatic ecosystems with very high nutrient loading, submerged macrophytes and phytoplankton may persist in an intermediate but potentially unstable state with medium water clarity. These findings may contribute to the understanding of the mechanisms involved in regime shifts in shallow lakes
Underwater noise pollution in China's Yangtze River critically endangers Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis)
No full textUnderwater sound plays an important role in some critical life functions of many aquatic animals. Underwater noise pollution has received relatively more attention in ocean systems. However, little attention has been paid to freshwater systems, such as the Yangtze River which is the habitat of critically endangered Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis). In 2012, the underwater noise levels in 25 sites along the middle and lower sections of the Yangtze River were measured. The root mean square sound pressure level (SPL) and unweighted sound exposure level (SEL) at each site ranged between 105 +/- 2.4 (median +/- quartile deviation) and 150 +/- 5.5 dB. Obvious spatial and temporal variations in the SPL were detected among the 25 sites. The SPL and SEL in the middle section of the Yangtze River were smaller (approximately 15 dB) and fluctuated more compared to those in the lower section. The power spectrum in the mainstem was site specific. However, all the spectra levels were higher than the audiogram of Yangtze finless porpoises. Majority of the sites had an averaged cumulative unweighted SEL (72%) and cumulative weighted SEL (68%) that surpassed the underwater acoustic thresholds for onset of hearing temporal threshold shifts for finless porpoise. Porpoise bio-sonars were detected in 89% of sonar monitoring sites indicating that noise pollution in the Yangtze River greatly threatened porpoise survival. In 8% of the sites, the averaged cumulative weighted SEL exceeded that of underwater acoustic thresholds causing non-recoverable permanent threshold shifts of finless porpoises auditory system whereas it was less than 1 dB below the underwater acoustic thresholds in other 8% of the sites. These sites urgently needed noise mitigation and management strategies. These results will facilitate the evaluation of the impacts of anthropogenic noise pollution on local finless porpoises and give further guidelines on its effective conservation. (C) 2020 Elsevier Ltd. All rights reserved
左炔诺孕酮对稀有鮈鲫脂质代谢的干扰效应
No full text为探究孕激素左炔诺孕酮(LNG)对鱼类脂质代谢的影响,将刚孵化的稀有鮑鲫仔鱼置于0.8和6.5ng/L LNG暴露6个月至性成熟,考察其生长指标、肝脏组织病理学变化、脂质和脂蛋白含量及脂质代谢相关基因的表达情况.结果显示:(1)0.8,6.5ng/L LNG暴露显著降低70dph稀有鮈鲫的体重和肥满度,且6.5ng/L LNG暴露显著降低180dph雌、雄鱼的体长或体重;(2) 0.8,6.5ng/L LNG暴露导致180dph成鱼肝脏出现细胞空泡、肝细胞肿胀等损伤;(3) 0.8,6.5ng/L LNG暴露显著降低180dph雌鱼肝脏中甘油三酯、胆固醇的含量,且6.5ng/L LNG暴露显著降低雌鱼血浆中甘油三酯的含量,但对雄鱼肝脏及血浆的脂质含量无显著影响;(4) 0.8,6.5ng/L LNG暴露显著降低180dph雌鱼肝脏中脂肪酸合成酶基因(fasn)mRNA的表达水平,且6.5ng/L LNG暴露显著降低180dph雄鱼肝脏中fasn及乙酰辅酶A羧化酶基因(acaca)mRNA的表达水平.由此可见,LNG长期低剂量暴露可抑制稀有鮈鲫的生长、诱导肝细胞损伤、引起肝脏和血浆脂质含量发生性别差异性变化,并影响肝脏中脂质代谢相关基因的表达,表明LNG在低浓度下可干扰稀有鮈鲫的脂质代谢,提示LNG对鱼类种群具有较高的潜在生态风险.</p
REVIEW PAPER ON TREATMENT OF INDUSTRIAL AND DOMESTIC WASTEWATERS USING UASB REACTORS INTEGRATED INTO CONSTRUCTED WETLANDS FOR SUSTAINABLE REUSE
No full textThe successful use of anaerobic technologies, especially up-flow sludge blanket (UASB) reactors for the treatment of raw domestic sewage and industrial wastewaters in tropical and subtropical countries opened the opportunity to substitute the aerobic processes with anaerobic reactors in removal of organic matter. Proper management of domestic and industrial wastewaters in developing nations is negligible. Even cost effective integrated green technologies like anaerobic reactor with constructed wetland technologies are not applied. Hence the objective of the present review was to assess the pollutant removal efficiency of the up flow anaerobic sludge blanket (UASB) reactor coupled with a constructed wetland (CW) in treating these wastewaters and their capability to produce quality water for sustainable reuse. To achieve the objectives, the review was organized using reputable journals, articles, and review papers. The interpretation of the result of each document was done using tables, bar graphs, Pie chart and lines. The results were reorganized again by calculating average flow rate, hydraulic loading rate, and percentage removal efficiencies. Most research results revealed that use of UASB-CW integrated treatment system is a promising technology in wastewater treatment and able to complying the effluent discharge standards Globally, the following abatement efficiencies ranged from 79.2-93.9%, 89.2-92.9%, 87.2-96.3%, 22.6-96.9%, 33-85.9%, and 97.9-99.99% were achieved for Chemical oxygen demand (COD), Biological oxygen demand (BOD), Total suspended solid (TSS), Total Kjeldhal Nitrogen (TKN), Total phosphorus (TP) and fecal Coliforms (FC), respectively using UASB-CW treatment systems. UASB-CW technologies are effectively integrated treatment systems and can be used for resource scarce developing countries. Since, both treatment technologies are cost-effective, easy operation and maintenance and capable of meeting effluent standards Hence, the indiscriminate disposal of wastewaters and their environmental impacts in Ethiopia can be resolved using these low-cost combined treatment technologies