Institute of Hydrobiology, Chinese Academy Of Sciences
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Genetic diversity, population structure, and historical gene flow of Nelumbo lutea in USA using microsatellite markers
No full textAmerican lotus (Nelumbo lutea Willd.) is a popular plant with ornamental, medicinal, and culinary value. Studies related to the genetic diversity and population structure of N. lutea are limited. We sampled 326 individuals from 19 populations of wild N. lutea across its distribution range in the USA and genotyped them using 12 microsatellite markers. A total of 274 alleles were amplified by 12 microsatellites with a mean of 22.83. We observed a low level of genetic diversity for American lotus (A(e) = 2.40 and H-E = 0.459) in the USA. The analysis of molecular variance (AMOVA) exhibited closer variation among populations (42.00%) than within populations (58.00%) of N. lutea, with strong genetic differentiation observed (F-ST = 0.419). There was no significant correlation between genetic and geographic distances. The Bayesian analysis and neighbor joining dendrogram displayed strong population structure. A very low level of historical gene flow (N-M = 0.073) was observed among the populations. Fourteen of the 19 populations showed a demographic bottleneck, indicating the vulnerability of the American lotus populations. We thus proposed priority population sites for the conservation of N. lutea via both ex-situ and in-situ techniques
Bioaugmentation treatment of nitrogen-rich wastewater with a denitrifier with biofilm-formation and nitrogen-removal capacities in a sequencing batch biofilm reactor
No full textA strain with efficient biofilm-formation and aerobic denitrification capabilities was isolated and identified as Pseudomonas mendocina IHB602. In pure culture, strain IHB602 removed almost all NO3--N, NO2--N, and NH4+-N (initial concentrations 50 mg/L) within 24 h. The strain produced large amounts of extracellular polymeric substances (maximum 430.33 mg/g cell dry weight) rich in protein but containing almost no humic acid. This, and strong autoaggregation (maximum 47.09%) and hydrophobicity (maximum 85.07%), imparted strain IHB602 with biofilm forming traits. A sequencing batch biofilm reactor bioaugmented with strain IHB602 (SBBR1) had more rapid biofilm-formation than the control without strain IHB602 inoculation (SBBR2). During the stabilization period, the effluent removal ratios for NH4+-N (95%), NO3--N (91%) and TN (88%) in SBBR1 were significantly higher than those in SBBR2 (NH4+-N: 91%, NO3--N: 88%, TN: 82%). Microbial community structure analysis revealed that strain IHB602 successfully proliferated and contributed to nitrogen removal as well as biofilm formation.</p
Integration of taxonomic distinctness indices into the assessment of headwater streams with a high altitude gradient and low species richness along the upper Han River, China
No full textThe multimetric index of biotic integrity (IBI) based on fish assemblages has been widely used to monitor aquatic ecosystem status in headwater streams. However, the application of the IBI has generally been biased by the low number of species and natural altitudinal gradients in these systems. To overcome these limitations, taxonomic distinctness and size-weight-based indices were integrated into our candidate metric pool, and calibration was performed to reduce the effects of the altitudinal gradient on the metrics in our study. Eighty-two sites in six headwater streams along a typical high altitude gradient and with low species richness were sampled. Eighty-three candidate metrics were selected to develop our IBI (IBI-Han) based on the systematic screening method. Six metrics based on taxonomic distinctness, habitat, tolerance guild, reproductive guild and trophic guild were finally retained in the IBI-Han: average taxonomic distinctness, percent rheophilic species, percent tolerant species, percent biomass of water column species, percent lithophilic species, and percent carnivorous species. The IBI-Han performed well in discriminating anthropogenic disturbances not only at training sites but also at testing sites, which suggests that our method could provide a reliable evaluation of the condition of headwater stream ecosystems. Among the six rivers, the Jinshui River showed relatively healthy ecosystem status, while the other five streams were disturbed by various human activities. Our work highlights that taxonomic distinctness indices are robust biomonitoring indices that can be combined with other functional indices to assess high altitude gradient streams in the upper Han River. We believe that the process of developing the IBI-Han could be regarded as a reference for managing headwater streams in other regions of China or in other states.</p
REVIEW PAPER ON BEVERAGE AGRO- INDUSTRIAL WASTEWATER TREATMENT PLANT BIO-SLUDGE FOR FERTILIZER POTENTIAL IN ETHIOPA
No full textAgro-industrial sectors in Ethiopia are highly expanding sector and offers substantial challenges for the environment and public health. The brewery industries use large quantities of water for their production processes and at the end, they discharged large amount of effluents that contains a high strength organic waste. The main objective of this review paper is to discuss and summarize the characteristics, treatment techniques, fertilizer potential and other available management options of breweries sludge generated from wastewater treatment plants. Recent (2015) research finding indicated that the brewery sludge contains a very high nitrogen and potassium content, i.e., 420.25 kg ha(-1) and 840 kg ha' respectively compared to the control. Scientific evidences indicated that brewery sludge amended soil they have the tendency to produce more yields (4081.6 kg ha(-1)). Brewery sludge has also other beneficial advantages in production of biogas and building materials with co-digestion with other organic solid residues. The probable drawbacks of the use of sludge on agricultural land application is its pollutant loads including heavy metals, organic compounds and pathogens. Therefore, more research investigation has to be done on the possible sludge treatment mechanisms and the feasibility of sludge generated from brewery industries for agricultural recycling
Synergistic toxicity of microcystin-LR and Cu to zebrafish (Danio rerio)
No full textToxic cyanobacterial blooms often coincide with metal pollution in a freshwater environment because of surface run-off enriched with nutrients and metals. However, the joint toxic effects of cyanobacterial toxins and metals on aquatic animals remain unknown. In this study, single and joint toxic effects and mechanisms of microcystinLR (MCLR) and copper (Cu) were investigated in the early development of zebrafish (Danio rerio). The LC50(72)(-h) values were 2.79 mg/L for MCLR and 3.23 mg/L for Cu. The sublethal concentrations of MCLR (<= 600 mu g/L) did not affect the normal development of zebrafish but increased its hatchability. Strong synergistic toxic effects were observed after co-exposure to MCLR and Cu at environmental concentrations (<= 60 mu g/L). The synergistic toxic effects of these two compounds could be attributed to the increased bioaccumulation of MCLR and Cu, which was mediated by MCLR transporters (e.g., oatp1d1 and oatp2b1) and Cu transporters (e.g., ctr1 and atp7a), in zebrafish. Such bioaccumulation caused oxidative stress, as suggested by the disrupted gene expression of anti-oxidative enzymes (e.g., Cu/Zn-SOD, Mn-SOD, and CAT). Our results revealed for the first time the synergistic toxic effects and potential toxic mechanism of MCLR-Cu in aquatic animals. These synergistic effects should be considered when assessing the ecological risk of toxic cyanobacterial blooms. (C) 2019 Published by Elsevier B.V
Patterns of fish communities and water quality in impounded lakes of China's south-to-north water diversion project
No full textUnderstanding the ecological impacts of large-scale hydraulic projects is critical for maintaining ecosystem health while meeting human water needs. It is, however, currently hindered by a lack of direct evidence on ecological impacts associated with this type of project particularly on water quality and fish communities. Here, we characterized patterns and variations of fish communities and water quality in five impounded lakes of the Chinese South-to-North Water Diversion Project (SNWDP), with the aim of better understanding potential ecological impacts of inter-basin water transfers. We found that 1) the impacts of water transfer on water quality in the impounded lakes was generally characterized by hydrological parameters (e.g. total suspended solids, turbidity, transparency, chlorophyll a, dissolved oxygen, conductivity and total hardness) in an upstream-downstream direction; 2) increased hydrological connectivity may have favored biological invasion (e.g. Tridentiger bifasciatus) and promoted a potential biotic homogenization among the impounded lakes: and 3) there was a pattern of decreased fish abundance and biomass from the upstream to downstream lakes with fish communities strongly driven by changing water quality patterns across the impounded lakes. These findings improve our understanding of ecological impacts of large-scale hydraulic projects and provide a significant basis for water agencies with similar water transfer systems to optimize their water transfer management in order to minimize ecological impacts. (C) 2020 Elsevier B.V. All rights reserved
Sequencing and characterization of the macronuclear rDNA minichromosome of the protozoan Tetrahymena pyriformis
No full textTetrahymena ribosomal DNA (rDNA) is an ideal system for studying eukaryotic DNA replication and gene transcription. In this study, we developed a new method to isolate rDNA from Tetrahymena cells and used it to sequence and annotate the complete 19,670 bp macronudear rDNA minichromosome of Tetrahymena pyriformis, a species that lacks the germ-line micronucleus and is unable to undergo sexual reproduction. The key features of T. pyriformis and Tetrahymena thermophila rDNA sequences were then compared. Our results showed (i) the short inverted repeats (M repeats) essential for formation of rDNA minichromosome palindromic structure during sexual reproduction in Tetrahymena are highly conserved in T. pyriformis; (ii) in contrast to T. thermophila. which has two tandem domains that coordinately regulate rDNA replication, T. pyriformis has only a single domain; (iii) the 35S pre-rRNA precursor has 8025% similarity between the two species; and (iv) the G + C content is higher in the transcribed region than the non-transcribed region in both species, but the GC-skew is more stable in T. pyriformis. The new isolation method and annotated information for the T. pyriformis rDNA minichromosome will provide a useful resource for studying DNA replication and chromosome copy number control in Tetrohymena. (C) 2020 Elsevier B.V. All rights reserved
Algicidal activity recovery by a Li-doped up-conversion material converting visible light into UV
No full textCitrobacter sp. R1, a highly efficient algicidal bacterium, undergoes a serious degeneration after long-term preservation. Here, we prepared a Li-doped up-conversion material ([Y2SiO5; Li (1%)]) to recover the degenerated Strain R1. As a result, the [Y2SiO5; Li (1%)] successfully enhanced the maximum algicidal activity of Strain R1 from 43.2 +/- 1.2 to 72.5 +/- 1.3%. In terms of recovery mechanisms, 1) the [Y2SiO5; Li (1%)] could convert visible light into UVC and UVA with unusual wavelengths, creating conditions for inducing reverse mutation in Strain R1, affecting the metabolism of Strain R1 and then recovering the bacterium; 2) the [Y2SiO5; Li (1%)] did not only enhance the secretion of 3-hydroxypropionic acid, the algicidal compoundwhich Strain R1 continues to produce even after degeneration, but also it recovered the ability of Strain R1 to secrete three new algicidal compounds. This study provides a new idea of employing up-conversion material [Y2SiO5; Li (1%)] in microbial degeneration recovery. (C) 2020 Elsevier B.V. All rights reserved.</p
Multifunctionality of biocrusts is positively predicted by network topologies consistent with interspecies facilitation
No full textThe potential of biodiversity loss to impair the delivery of ecosystem services has motived ecologists to better understand the relationship between biodiversity and ecosystem functioning. Although increasing evidence underlines the collective contribution of different biodiversity components on the simultaneous performance of multiple functions (multifunctionality), we know little about the trade-offs between individual diversity effects and the extent to which they determine multifunctionality differentially. Here, at a subcontinental scale of 62 dryland sites, we show in phototrophic microbiota of biological soil crusts (biocrusts) that, whereas richness alone is unable to guarantee the maxima of multifunctional performance, interspecies facilitation and compositional identity are particularly stronger but often neglected predictors. The inconsistent effects of different biodiversity components imply that soil multifunctionality can be lost despite certain species remaining present. Moreover, we reveal a significant empirical association between species functional importance and its topological feature in co-occurrence networks, indicating a functional signal of species interaction. Nevertheless, abundant species tend to isolate and merely interact within small topological structures, but rare species were tightly connected in complicated network modules. Our findings suggest that abundant and rare species of soil phototrophs exhibit distinct functional relevance. These results give a comprehensive view of how soil constructive species drive multifunctionality in biocrusts and ultimately promote a deeper understanding of the consequences of biodiversity loss in real-world ecosystems
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,将刚孵化的稀有鮈鲫仔鱼置于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