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Nitrogen-cycling microbial community functional potential and enzyme activities in cultured biofilms with response to inorganic nitrogen availability 被引量:4
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作者 Shuangshuang li Chengrong Peng +3 位作者 Taisheng Cheng Chun Wang liangliang Guo dunhai li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2019年第2期89-99,共11页
Biofilms mediate crucial biochemical processes in aquatic ecosystems. It was hypothesized that eutrophication may promote the growth of biofilms, resulting in larger numbers of functional genes. However, the metabolic... Biofilms mediate crucial biochemical processes in aquatic ecosystems. It was hypothesized that eutrophication may promote the growth of biofilms, resulting in larger numbers of functional genes. However, the metabolic activity and the roles of biofilms in N cycling will be affected by ambient inorganic nitrogen availability, not by the abundance of functional genes. Biofilms were cultured either with replete inorganic nitrogen(N-rep) or without exogenous inorganic nitrogen supply(N-def) in a flow incubator, and the N-cycling gene abundances(nifH, N_2 fixation; amoA, ammonia oxidation, archaea and bacteria; nirS and nirK, denitrification) and enzyme activities(nitrogenase and nitrate reductase) were analyzed. The results showed that, comparing the N-def and N-rep biofilms, the former contained lower nifH gene abundance, but higher nitrogenase activity(NA), while the latter contained higher nifH gene abundance, but lower NA. Different patterns of NA diel variations corresponded to the dynamic microbial community composition and different stages of biofilm colonization. Ammonia oxidizing bacteria(AOB), detected only in N-def biofilms, were responsible for nitrification in biofilms. N-rep biofilms contained high nirS and nirK gene abundance and high denitrification enzyme activity, but N-def biofilms contained significantly lower denitrification gene abundance and activity. In general,the strong N_2 fixation in N-def biofilms and strong denitrification in N-rep biofilms assured the balance of aquatic ecosystems. The results suggested that evaluation of the functional processes of N cycling should not only focus on genetic potential, but also on the physiological activity of biofilms. 展开更多
关键词 CULTURED biofilms NITROGEN AVAILABILITY Nitrogen-cycling enzymes Nitrogen-cycling genes
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Influence of phosphorus availability on the community structure and physiology of cultured biofilms 被引量:1
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作者 Shuangshuang li Chun Wang +4 位作者 Hongjie Qin Yinxia li Jiaoli Zheng Chengrong Peng dunhai li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第4期19-31,共13页
Biofilms have important effects on nutrient cycling in aquatic ecosystems.However,publications about the community structure and functions under laboratory conditions are rare.This study focused on the developmental a... Biofilms have important effects on nutrient cycling in aquatic ecosystems.However,publications about the community structure and functions under laboratory conditions are rare.This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator.The results showed that the biomass(Chl a)and photosynthesis of algae were inhibited under P-limitation conditions,while the phosphatase activity and P assimilation rate were promoted.The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability.Cyanobacteria were more competitive than other algae in biofilms,particularly when cultured under low P levels.A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01,0.1 and 0.6 mg/L.However,the total N content,dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability.This may be attributed to the low respiration rate,high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low.The bacterial community structure differed over time,while there was little difference between the four treatments,which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability.Altogether,these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water. 展开更多
关键词 Chlorophyll fluorescence Cultured biofilms Microbial community structure Phosphatase activity Phosphorus availability
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Competition between toxic and nontoxic Microcystis (Cyanophyceae) under different light and temperature conditions
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作者 Yinxia li Yiwen Wu +1 位作者 Bibo liu dunhai li 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第6期674-676,共3页
Dear Editor,In aquatic environments,cyanobacteria usually proliferate faster than other phytoplankton assemblages during warm seasons,particularly in eutrophic waters(Ma et al.,2015).Microcystis,a common cyanobacteria... Dear Editor,In aquatic environments,cyanobacteria usually proliferate faster than other phytoplankton assemblages during warm seasons,particularly in eutrophic waters(Ma et al.,2015).Microcystis,a common cyanobacterial genus that potentially produces microcystins(MCs)and nontoxic strains,dominates in eutrophic freshwater bodies,and its biomass increases quickly during the warm period;these changes result in increased water turbidity and changes in light quality and quantity in the water column(Li and Li,2012).Additionally, 展开更多
关键词 Microcystis proliferate phytoplankton potentially faster biomass quickly aquatic bloom waters
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Cyanobacteria-/cyanotoxin-contaminations and eutrophication status before Wuxi Drinking Water Crisis in Lake Taihu, China 被引量:21
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作者 Yongmei liu Wei Chen +3 位作者 dunhai li Zebo Huang Yinwu Shen Yongding liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2011年第4期575-581,共7页
After the appalling "Wuxi Drinking Water Crisis", increasing investigations concerning the contaminations of cyanobacterial blooms and their toxins in Lake Taihu have been performed and reported in the last two year... After the appalling "Wuxi Drinking Water Crisis", increasing investigations concerning the contaminations of cyanobacterial blooms and their toxins in Lake Taihu have been performed and reported in the last two years. However, information regarding these issues before the crisis in 2007 remained insufficient. To provide some background data for further comparisons, the present study reported our investigations conducted in 2004, associated with the cyanotoxin contaminations as well as the eutrophication status in Lake Taihu. Results from the one-year-study near a drinking water resource for Wuxi City indicated that, unlike the status in recent two years, cyanobacteria and chlorophyta are the co-dominance species throughout the year. The highest toxin concentration (34.2 ng/mL) in water columns occurred in August. In bloom biomass, the peak value of intracellular toxin (0.59 μg/mg DW) was determined in October, which was lag behind that in water column. In addition, MC-RR was the major toxin variant throughout the year. During the study period, nutrients levels of total nitrogen and phosphorus were also recorded monthly. Results from the present study will lead to a better understanding of the eutrophication status and the potential risks before "Wuxi Drinking Water Crisis". 展开更多
关键词 cyanobacterial blooms EUTROPHICATION MICROCYSTINS Lake Taihu
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The influence of desiccation on the recovery process of nitrogenase activity in restored biological soil crusts
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作者 Jiaoli Zheng Shuangshuang li +1 位作者 Chengrong Peng dunhai li 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第11期1283-1285,共3页
Dear Editor,Biological soil crusts(BSCs),a layered structure formed by associations of soil organisms and topsoil,dominate arid and semiarid areas and serve important ecological functions in these areas(Eldridge and G... Dear Editor,Biological soil crusts(BSCs),a layered structure formed by associations of soil organisms and topsoil,dominate arid and semiarid areas and serve important ecological functions in these areas(Eldridge and Greene,1994).Nitrogen fixation by BSCs is the main source of N in arid and semi-arid ecosystems.Desiccation is the most notable factor that influences BSCs,which recover physiological activity only after moistening.By influencing the amount of carbohydrates, 展开更多
关键词 The influence DESICCATION the recovery process nitrogenase activity restored biological soil crusts
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Mitochondrial electron transport chain is involved in microcystin-RR induced tobacco BY-2 cells apoptosis
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作者 Wenmin Huang dunhai li Yongding liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第9期1930-1935,共6页
Microcystin-RR (MC-RR) has been suggested to induce apoptosis in tobacco BY-2 cells through mitochondrial dysfunction including the loss of mitochondrial membrane potential . TO further elucidate the mechanisms invo... Microcystin-RR (MC-RR) has been suggested to induce apoptosis in tobacco BY-2 cells through mitochondrial dysfunction including the loss of mitochondrial membrane potential . TO further elucidate the mechanisms involved in MC-RR induced apoptosis in tobacco BY-2 cells, we have investigated the role of mitochondrial electron transport chain (ETC) as a potential source for reactive oxygen species (ROS). Tobacco BY-2 cells after exposure to MC-RR (60 mg/L) displayed apoptotic changes in association with an increased production of ROS and loss of Am. All of these adverse effects were significantly attenuated by ETC inhibitors including Rotenone (2 μmol/L, complex I inhibitor) and antimycin A (0.01 μmol/L, complex III inhibitor), but not by thenoyltrifluoroacetone (S μmol/L, complex Ⅱinhibitor). These results suggest that rnitochondrial ETC plays a key role in mediating MC-RR induced apoptosis in tobacco BY-2 cells through an increased mitochondrial production of ROS. 展开更多
关键词 Microcystin-RRTobacco BY-2 cellsApoptosisReactive oxygen speciesMitochondrial electron transport chain
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