Institute of Hydrobiology, Chinese Academy Of Sciences
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中国淡水水华甲藻一新记录种及其生态风险
No full text2019年6月,在山东省峡山水库多个位点采集到角藻属(Ceratium)样品,并发现其在局部位点形成明显的浅褐色水华.系统发育分析结果显示该种与角藻属常见种飞燕角藻(C.hirundinella)亲缘关系最近,但形态学上有明显区别,前者具有1块间插板和3个顶板,而飞燕角藻具有4块顶板.通过对比,发现该种为我国淡水甲藻门未经描述的新记录物种——拟二叉角藻(C.furcoides).峡山水库中,水华发生位点的水体叶绿素a浓度高达125.77μg/L,拟二叉角藻的密度达1.23×106cells/L,占总藻细胞密度的1.21%.细胞数量上,占优势的主要是尖头藻(Merismopedia spp.)和浮丝藻(Planktothrix spp.)等一些丝状蓝藻;但因个体细胞体积非常大,鲜重高达86.31 mg/L,占总藻鲜重的49.34%,因此在生物量上拟二叉角藻是绝对优势种.此外,通过核查采自我国东北、华中、西南地区不同时期、温度较高季节的多个标本,基于其自身特性和分布特点,本研究认为拟二叉角藻偏好高温和富营养水体,有在我国不同地区水体扩张并形成水华的潜在能力
Chemicals affect color preference in rare minnow (Gobiocypris rarus)
No full textBehavioral response of fish has been shown that was sensitive to chemicals in water. Herein, larval and adult rare minnows of Gobiocypris rarus were studied for their innate color preference and response to a concentration gradient of chemicals (cadmium ion [Cd2+], tricaine methanesulfonate [MS222], and p-chloroaniline). The results showed that both larval and adult rare minnows preferred blue and green over yellow and red in water with no chemicals added. Larval color preference changed significantly under concentrations of Cd2+ >= 0.4 mg/L, MS222 >= 3 mg/L, and p-chloroaniline >= 10 mg/L; for adults, color preference changed significantly when Cd2+ >= 3 mg/L, MS222 >= 34 mg/L, and p-chloroaniline >= 38 mg/L. In addition, the color preference priorities of both larvae and adults also changed at high concentrations of chemicals. The present study provides useful information on how changes in rare minnow behavior could be used as an early indicator of water pollution
Proteomic identification and expression of oral apparatus constituents in cell regeneration of giant ciliate Stentor coeruleus (strain WHEL)
No full textThe giant ciliate Stentor coeruleus (S. coeruleus) is a suitable model organism for studying morphogenesis and regeneration at the single-cell level. It contains a prominent structure on the anterior end of the cell, known as the oral apparatus (OA). OA can be induced to shed by urea treatment and then new OA regenerates via a series of defined morphological events and the cell resumes normal feeding activity. We identified OA constituents in S. coeruleus by mass spectrometry. A total of 882 OA-associated proteins were identified; the homologs of 181 of these are known OA constituents in other organisms. The expression pattern of OA-associated genes during regeneration was investigated using single-cell transcriptome sequencing. The expression of most OA-associated genes was high during regeneration, indicating their stable expression after OA shedding. We also identified OA-associated differentially expressed genes that may be involved in regulating OA reconstruction. In summary, this study gives preliminary insight into the molecular basis of OA in S. coeruleus
Opposite effects of the earthworm Eisenia fetida on the bioavailability of Zn in soils amended with ZnO and ZnS nanoparticles
No full textThe increasing release of metallic nanoparticles (NPs) or their sulfidized forms into soils have raised concerns about their potential risks to soil ecosystems. Hence, there is a need for novel strategies to remediate metallic NPs pollution in soils. In this study, to explore the feasibility of using earthworm Eisenia fetida to manage soils contaminated with metallic NPs, we simultaneously investigated the chronic soil toxicities of ZnO NPs and ZnS NPs to E. fetida, and the effects of E. fetida on Zn extractability in soils amended with ZnO NPs and ZnS NPs. After a 28 d exposure, survival rate and weight loss of earthworms were not impacted by either ZnO NPs or ZnS NPs at a concentration of 400 mg Zn per kg soil. Further, while ZnO NPs activated earthworm antioxidative system, ZnS NPs resulted in significant alleviation of oxidative damage in earthworm. The presence of earthworms significantly decreased the bioavailability of Zn in ZnO NPs contaminated soil, whereas significantly increased the bioavailability of Zn in ZnS NPs contaminated soil. These findings implied that the earthworm E. fetida could play an important role in altering the mobilization of metals originating from metallic NPs in soils, which may further aid in the development of a method for the treatment of metallic NPs pollution in soils. (C) 2020 Elsevier Ltd. All rights reserved
Effects of macrophytes on ecosystem metabolism and net nutrient uptake in a groundwater fed lowland river
No full textTransport and transformation of inorganic nutrients are influenced by abiotic-biotic interactions and determine downstream water quality. Macrophytes play an important role in these complex ecological interactions. The role of macrophytes was studied in three reaches of the groundwater-fed, oligotrophic River Fischa with different macrophyte coverage and biomass. This was done by measuring metabolism and calculating changes in nutrient loading and concentrations, which were determined via an upstream-downstream mass balance approach. As the dominant autotrophs, we expected macrophytes (i) to have a direct effect by uptake and release, and (ii) an indirect effect by slowing down flow, which results in changed sedimentation patterns and altered conditions for heterotrophic microbial organisms implicating higher turnover and uptake rates.
The seasonal development of macrophytes in 2017 had a strong impact on gross primary production, but not on ecosystem respiration. Increase in macrophyte biomass led to higher GPP (max. 5.4 g O(2)m(-2)d(-1)). ER was highest in autumn in the reach with intermediate macrophyte biomass (max. 10.1 g O(2)m(-2)d(-1)). We observed that the autotrophic uptake of phosphorus accounted for 80-145% of the P-PO4-flux and concluded that P-uptake by macrophytes from the sediment is an important source of phosphate for macrophytes in the river. By accumulating fine sediment, macrophytes are improving the availability of phosphate for their own long-term development. N-NO3, represented >99% of the nitrogen flux. N-NO3 net uptake was higher in the reaches with more macrophytes (0.84 vs. 0.12 g m(-2)d(-1)), but in average only 21% of the net uptake could be related to autotrophic nitrogen uptake in the reach with high macrophyte biomass. Dissimilatory uptake by heterotrophic organisms, most probably denitrification, were of high relevance. Macrophytes supported microbial uptake and release by improving conditions and slowing down flow. In the River Fischa, an oligotrophic river with low variability of environmental parameters, macrophytes greatly affected nutrient uptake by direct and indirect pathways. (C) 2020 The Authors. Published by Elsevier B.V
Study on the safe disposal and resource utilization of cyanobacterial bloom biomass in Dianchi Lake, China
No full textTo solve the problem of utilizing massive harmful algal blooms (HABs) biomass, we developed a technique involving physical purification methods, namely, microfiltration (2 mu m, 0.45 mu m), ultrafiltration (100 kDa cutoff), and low-temperature precipitation (4 degrees C, 48 h), as the core methodology and used the toxic Microcystis biomass in Dianchi Lake for batch preparations of microcystins (MCs) and phycocyanin (PC). The results were as follows: (1) From 1.0 kg of Dianchi Lake cyanobacteria, 57 g of PC powder with a purity (A(620)/A(280)) of 1.78 was prepared. An acute oral toxicity test in mice showed that the LD50 of the prepared PC was >5.25 g kg(-1), practically non-toxic. The LD50 of PC administered by intraperitoneal injection was >4.71 g kg(-1). The Ames test showed that the mutagenic effect was negative independent of the addition of S9. The overall results of the toxicity tests suggested that the prepared PC was not potentially toxic. (2) From 666.7 g of cyanobacteria, 2.262 g of MC extract powder (containing 192.7 mg of MC-RR and 54.3 mg of MC-LR) was prepared. MC-RR and MC-LR accounted for 8.52% and 2.40%, respectively, and the extraction ratios for MC-RR and MC-LR were 40.1% and 83.1%, respectively. A further purification by preparative HPLC was carried out, obtaining 2.338 mg of pure MC-RR (chromatographic purity >85%) from 70 mg of MC extract powder, which was used as an HPLC chromatographic standard and in routine toxicology experiments. The efficiency of the ultrafiltration treatment of cyanobacterial powder reached 49.3 kg d(-1), and the cost of producing food-grade PC powder in this study was 17.6 US$ g(-1), which is only 13.6% of the current price of food-grade PC on the international market. Thus, the cost advantage was significant. Therefore, this study provides an approach for the safe disposal of HABs and the large-scale commercial utilization of HAB biomass
Andrias davidianus ranavirus 1R encoding a delayed-early protein promotes cell proliferation by driving cell cycle progression into S phase
No full textAndrias davidianus ranavirus 1R (ADRV-1R), a core gene of the family Iridoviridae, is predicted to encode a viral transcription factor (vTF) since the protein contains a virus late transcription factor-3 like (VLTF3 like) domain. However, its characteristics and function are still unclear. In this study, the transcription and expression of ADRV-1R were investigated in Chinese giant salamander thymus cells (GSTCs). ADRV-1R transcription starts 6 hours post-infection (hpi), while the protein expression starts 8 hpi. Drug inhibition assay showed that the transcripts are inhibited by cycloheximide (CHX), a de novo protein synthesis inhibitor, indicating that ADRV-1R is a viral delayed-early (DE) gene. Subcellular localization showed that ADRV-1R is distributed in the cell nucleus and cytoplasm. The effect of ADRV-1R overexpression on cell proliferation and virus titer was analyzed. ADRV-1R overexpression significantly promoted the cell proliferation starting at day 2. Flow cytometry analysis further indicated that the protein promotes the GSTC cell cycle progression from GI phase into S phase (Gl/S transition). Moreover, ADRV-1R overexperession significantly increased ADRV titer in GSTCs. The virus titer was 6.3-6.9-fold higher at 36 hpi and further after than the control GSTC lines. These data showed that ADRV-1R is a delayed-early protein promoting cell proliferation and virus titers
如何对濒危物种进行评估与拯救
No full text物种的灭绝本是一个自然过程,但人类的繁荣使数以百万计的生物物种的栖息地被蚕食,很多物种以惊人的速度灭绝了(如长江中的白鱀豚和白鲟)或正在绝灭之中(中华鲟),但却未伴随新物种的自然产生.世界自然保护联盟虽然确定了物种濒危的等级标准,但定量划分标准的象征意义大于实际意义,因为不可能所有生物物种都能通过同一种种群动态模式去预测它们未来的命运.关于物种的濒危机制,人们提出了许多基于种群数量变动的理论概念(如最小生存种群、有效种群大小、种群瓶颈、奠基者效应、“阿利”效应、灭绝漩涡等),但可操作性不强,对保护生物学的实际指导意义不大.本文提出了物种生存状态转化的概念模型,物种生存状态主要取决于物种对外在环境的综合生存适合度f_((s))和灭绝风险R,受到①物种生存空间的完整性、②生态过程的适宜性、③食物的可得性、④对人为致死或自然灾害的抵抗力等的影响. f_((s))由物种对若干决定性生存因子s_1、s_2、s_3…的适合度之乘积所决定: f_((s))= f_((s1)) f_((s2)) f_((s3)) ……,f_((s))取值0~ 1,1表示最大的适合度(理想生存状态),0表示彻底丧失了适合度,因此,任何一个决定性生存因子的趋零,都会导致该物种的灭绝(木桶效应).物种的生存状态指数H_((f,R))由f_((s))和R联合决定.可用f_((s))来评估与预测物种的灭绝风险(譬如,可区分为3~ 4个风险等级),突变临界点之前的动态过程可作为物种濒危的早期预警信号,物种拯救临界点可作为保护性干预的最低目标.当然,这里只是提出了一个概念模型,各个决定性生存因子的适合度函数f_((s))有待确定,并需要以真实的物种为对象进行验证.</p
The effect of natural materials used as sediment remediation on phosphorus and nitrogen control in a mesocosm
No full textAbstractBackgroundAchieving nitrogen (N) and phosphorus (P) control in sediment remediation projects by adding natural materials is receiving increasing attention. In this study, different natural materials, including iron-rich clay minerals, calcite, kaoline, sugarcane bagasse and Phragmites detritus, were applied to test their effects on N and P in a mesocosm experiment.ResultsIron-rich clay minerals and Phragmites detritus had obvious advantages for P control; they resulted in almost undetectable levels of soluble reactive phosphorus (SRP) in the water column throughout the experiment. This finding can be explained by their strong P adsorption ability. The high level of available organic carbon in the sediment and water column after sugarcane bagasse addition provided enough electron donors for denitrification and dissimilatory nitrate reduction to ammonium (DNRA), which caused nitrate (NO3?-N) deficiency and ammonium (NH4+-N) accumulation in the water column. Additionally, this resulted in anaerobic conditions, further fuelling the release of P from iron-bound P induced by anoxia. Thus, the amount of sugarcane bagasse applied should be considered carefully in order to balance denitrification and DNRA as well as P releases. Calcite and Phragmites detritus are recommended as remediation materials for N removal based on their significant promotion of denitrification and limitation of DNRA, which resulted in low NO3?-N and NH4+-N levels. These results can be explained by the shifts in the functional microbial community composition and abundance after the addition of natural materials.ConclusionsIron-rich clay minerals and Phragmites detritus are promising sediment remediation materials for P immobilization due to their strong P adsorption ability. Taken together, the selection of sediment remediation materials should consider the N and P coupling relationship, to prevent NO3?-N removal from causing P leaching or NH4+-N accumulation
Use statistical machine learning to detect nutrient thresholds in Microcystis blooms and microcystin management
No full textThe frequency of toxin-producing cyanobacterial blooms has increased in recent decades due to nutrient enrichment and climate change. Because Microcystis blooms are related to different environmental conditions, identifying potential nutrient control targets can facilitate water quality managers to reduce the likelihood of microcystins (MCs) risk. However, complex biotic interactions and field data limitations have constrained our understanding of the nutrient-microcystin relationship. This study develops a Bayesian modelling framework with intracellular and extracellular MCs that characterize the relationships between different environmental and biological factors. This model was fit to the across-lake dataset including three bloom-plagued lakes in China and estimated the putative thresholds of total nitrogen (TN) and total phosphorus (TP). The lake-specific nutrient thresholds were estimated using Bayesian updating process. Our results suggested dual N and P reduction in controlling cyanotoxin risks. The total Microcystis biomass can be substantially suppressed by achieving the putative thresholds of TP (0.10 mg/L) in Lakes Taihu and Chaohu, but a stricter TP target (0.05 mg/L) in Dianchi Lake. To maintain MCs concentrations below 1.0 mu g/L, the estimated TN threshold in three lakes was 1.8 mg/L, but the effect can be counteracted by the increase of temperature. Overall, the present approach provides an efficient way to integrate empirical knowledge into the data-driven model and is helpful for the management of water resources