Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments.After a period of dormancy,organisms often exhibit exceptional resilience.This period is typically divided into ...Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments.After a period of dormancy,organisms often exhibit exceptional resilience.This period is typically divided into hibernation and aestivation based on seasonal patterns.However,the mechanisms by which organisms adapt to their environments during dormancy,as well as the potential relationships between different states of dormancy,deserve further exploration.Here,we selected Perccottus glenii and Protopterus annectens as the primary subjects to study hibernation and aestivation,respectively.Based on histological and transcriptomic analysis of multiple organs,we discovered that dormancy involved a coordinated functional response across organs.Enrichment analyses revealed noteworthy disparities between the two dormant species in their responses to extreme temperatures.Notably,similarities in gene expression patterns pertaining to energy metabolism,neural activity,and biosynthesis were noted during hibernation,suggesting a potential correlation between hibernation and aestivation.To further explore the relationship between these two phenomena,we analyzed other dormancy-capable species using data from publicly available databases.This comparative analysis revealed that most orthologous genes involved in metabolism,cell proliferation,and neural function exhibited consistent expression patterns during dormancy,indicating that the observed similarity between hibernation and aestivation may be attributable to convergent evolution.In conclusion,this study enhances our comprehension of the dormancy phenomenon and offers new insights into the molecular mechanisms underpinning vertebrate dormancy.展开更多
Stearyl coenzyme A desaturase(SCD), also known as delta-9 desaturase, catalyzes the rate-limiting step in the formation of monounsaturated fatty acids.In mammals, depletion or inhibition of SCD activity generally lead...Stearyl coenzyme A desaturase(SCD), also known as delta-9 desaturase, catalyzes the rate-limiting step in the formation of monounsaturated fatty acids.In mammals, depletion or inhibition of SCD activity generally leads to a decrease in triglycerides and cholesteryl esters. However, the endogenous role of scd in teleost fish remains unknown. Here, we generated a zebrafish scd mutant(scd-/-) to elucidate the role of scd in lipid metabolism and sexual development. Gas chromatography-mass spectrometry(GC-MS) showed that the scd-/- mutants had increased levels of saturated fatty acids C16:0 and C18:0, and decreased levels of monounsaturated fatty acids C16:1 and C18:1. The mutant fish displayed a short stature and an enlarged abdomen during development. Unlike Scd-/ -mammals, the scd-/- zebrafish showed significantly increased fat accumulation in the whole body,especially in the liver, leading to hepatic mitochondrial dysfunction and severe cell apoptosis.Mechanistically, srebf1, a gene encoding a transcriptional activator related to adipogenesis,acc1 and acaca, genes involved in fatty acid synthesis, and dgat2, a key gene involved in triglyceride synthesis, were significantly upregulated in mutant livers to activate fatty acid biosynthesis and adipogenesis. The scd-/- males exhibited defective natural mating behavior due to defective genital papillae but possessed functional mature sperm. All defects in the scd-/- mutants could be rescued by ubiquitous transgenic overexpression of scd. In conclusion, our study demonstrates that scd is indispensable for maintaining lipid homeostasis and development of secondary sexual characteristics in zebrafish.展开更多
Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We rece...Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We recently identified zona pellucida(Zp) as the top differentially expressed protein between East Asian cyprinids that produce adhesive and semi-buoyant eggs,suggesting that Zp protein may play important roles in the regulation of egg type.In this work,we generated transgenic zebrafish in which oocyte-specific expression of zp genes from rare minnow(Gobiocypris rarus),an East Asian cyprinid laying adhesive eggs,was driven by a zebrafish zp3.2 gene promoter.We found that the transgenic eggs obtained partial adhesiveness and exhibited alteration in hydration and buoyancy.Abnormal metabolism of vitellogenin(VTG) may contribute to enhanced hydration and/or buoyancy.Our work shows that expression of the exogenous zp3a gene from an adhesiveegg producing fish is sufficient to induce changes in both egg adhesiveness and buoyancy in zebrafish,emphasizing the important role of zp genes in the regulation of spawning habits.Our results thus provide new insights into how endemic East Asian cyprinids may have adapted to the Yangtze river-lake system via changes in spawning habits.展开更多
The physiological responses of Nitzschia palea Kützing,a freshwater diatom,to elevated CO2 were investigated and compared with those of a marine diatom,Chaetoceros muelleri Lemmermann previously reported.Elevated...The physiological responses of Nitzschia palea Kützing,a freshwater diatom,to elevated CO2 were investigated and compared with those of a marine diatom,Chaetoceros muelleri Lemmermann previously reported.Elevated CO_2 concentration to 700μl/L increased the dissolved inorganic carbon (DIC) and lowered the pH in the cultures of N.palea,thus enhancing the growth by 4%-20% during the whole growth period.High CO2-grown N.palea cells showed lower levels of dark respiration rates and higher I_k values.Light-saturated photosynthetic rates and photosynthetic efficiencies decreased in N. palea with the doubling CO_2 concentration in airflow to the bottom of cultures,although the doubling CO_2 concentration in airflow to the surface cultures had few effects on these two photosynthetic parameters.N.palea cells were found to be capable of using HCO_3^-in addition to gaseous CO_2,and the CO_2 enrichment decreased their affinity for HCO_3^-and CO_2.Although doubled CO_2 level would enhance the biomass of N.palea and C.muelleri to different extents,compared with the marine diatom,it had a significant effect on the specific growth rates of N.palea.In addition,the responses of photosynthetic parameters of N.palea to doubled CO:concentration were almost opposite to those of C.muelleri.展开更多
A comprehensive study of the invasive icefish Neosalanx taihuensis feeding ecology in Erhai Lake was conducted from November 2009 to October 2010. Prey items in the guts of the icefish sampled varied significantly acc...A comprehensive study of the invasive icefish Neosalanx taihuensis feeding ecology in Erhai Lake was conducted from November 2009 to October 2010. Prey items in the guts of the icefish sampled varied significantly according to season. This finding suggests a relationship between fluctuations in available prey in the environment and selective feeding by icefish. N. taihuensis preferred large-sized zooplankton,such as Daphnia and calanoids. Additionally,the gut fullness values differed significantly( P <0.001) among sampling times. To compare the values at different times,samples were taken over a 24 h period every 2 months for the entire year. The feeding activities of the fish were concentrated either in the morning(8:00) and/or at dusk(20:00),except in September 2010. This finding can be explained primarily by the variation in optimum light intensity. Daily N. taihuensis zooplankton consumption varied significantly,both diurnally and among seasons. The daily consumption values ranged from 0.089 to 0.237 g(wet weight) per 100 g wet fish weight in temperatures between 11.50°C and 24.68°C. This is the first report of diel feeding periodicity and daily food consumption of icefish in their invaded ecosystems.展开更多
Omega-3 polyunsaturated fatty acids(n-3 PUFAs),particularly docosahexaenoic acid(22:6n-3,DHA),play crucial roles in the reproductive health of vertebrates,including humans.Nevertheless,the underlying mechanism related...Omega-3 polyunsaturated fatty acids(n-3 PUFAs),particularly docosahexaenoic acid(22:6n-3,DHA),play crucial roles in the reproductive health of vertebrates,including humans.Nevertheless,the underlying mechanism related to this phenomenon remains largely unknown.In this study,we employed two zebrafish genetic models,i.e.,elovl2^(-/-)mutant as an endogenous DHAdeficient model and fat1(omega-3 desaturase encoding gene)transgenic zebrafish as an endogenous DHA-rich model,to investigate the effects of DHA on oocyte maturation and quality.Results show that the elovl2^(-/-)mutants had much lower fecundity and poorer oocyte quality than the wild-type controls,while the fat1 zebrafish had higher fecundity and better oocyte quality than wildtype controls.DHA deficiency in elovl2^(-/-)embryos led to defects in egg activation,poor microtubule stability,and reduced pregnenolone levels.Further study revealed that DHA promoted pregnenolone synthesis by enhancing transcription of cyp11a1,which encodes the cholesterol side-chain cleavage enzyme,thereby stabilizing microtubule assembly during oogenesis.In turn,the hypothalamic-pituitary-gonadal axis was enhanced by DHA.In conclusion,using two unique genetic models,our findings demonstrate that endogenously synthesized DHA promotes oocyte maturation and quality by promoting pregnenolone production via transcriptional regulation of cyp11a1.展开更多
Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males.However,the mechanisms by which testosterone acts on lipid metabolism are not yet fully unders...Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males.However,the mechanisms by which testosterone acts on lipid metabolism are not yet fully understood,especially in teleosts.In this study,cyp17a1-/-zebrafish(Danio rerio)exhibited excessive visceral adipose tissue(VAT),lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis(DNL)enzymes.The assay for transposase accessible chromatinwithsequencing(ATAC-seq)results demonstrated that chromatin accessibility of DNL genes was increased in cyp17a1-/-fish compared to cyp17a1+/+male fish,including stearoyl-CoA desaturase(scd)and fatty acid synthase(fasn).Androgen response element(ARE)motifs in the androgen signaling pathway were significantly enriched in cyp17a1+/+male fish but not in cyp17a1-/-fish.Both androgen receptor(ar)-/-and wildtype(WT)zebrafish administered with Ar antagonist flutamide displayed excessive visceral adipose tissue,lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis enzymes.The Ar agonist BMS-564929 reduced the content of VAT and lipid content,and down-regulated acetyl-CoA carboxylase a(acaca),fasn,and scd expression.Mechanistically,the rescue effect of testosterone on cyp17a1-/-fish in terms of phenotypes was abolished when ar was additionally depleted.Collectively,these findings reveal that testosterone inhibits lipid deposition by down-regulating DNL genes via Ar in zebrafish,thus expanding our understanding of the relationship between testosterone and lipid metabolism in teleosts.展开更多
Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total s...Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total suspended solids,Chlorophyll a and Secchi transparency in the water column was found,while levels of water depth,electrical conductivity,total dissolved solids and NO 3--N concentration increased markedly post-dredging.The effects of dredging on dissolved oxygen,pH value and temperature were almost negligible.The zooplankton community structure responded rapidly to the environmental changes caused mainly by dredging.As a result,the abundance of rotifers decreased,while the density of zooplanktonic crustaceans increased markedly.The representative taxa were Brachionus angularis,B.budapestinensis,B.diversicornis,Synchaeta spp.and Neodiaptomus schmackeri.A distinct relationship between zooplankton taxa composition and their environment,unraveled by a redundancy analysis,indicating that the measured environment contributed to the variations in the zooplankton community structure to some extent.The first four synthetic environmental variables explained 51.7% of the taxonomic structure.Therefore,with the reduction of internal nutrient load and a shift in dominance by less eutrophic species,it inferred that dredging might be one of effective measures for environmental improvements of such lakes.展开更多
Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid ...Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid (PLFA) composition. A total of 20 fatty acids in the range of C11 to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in different media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant differences among the eight different media by Tukey's honestly test. It was found that steel slag was significantly different in the microbial community as compared to other filter media, probably due to its alkaline efluent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis (PCA) showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.展开更多
Freshwater aquaculture plays an important role in the global aquaculture industry.The success of freshwater aquaculture relies on the integration of bio-ecological remediation technologies to ensure its sustainable de...Freshwater aquaculture plays an important role in the global aquaculture industry.The success of freshwater aquaculture relies on the integration of bio-ecological remediation technologies to ensure its sustainable development.This paper systematically reviews the global literatures on bio-ecological remediation of freshwater aquaculture environments from 1990 to 2021,and discusses in detail the research progress and status quo in this field using both bibliometric analysis and content analysis.Our results indicate that the number of publications per year has increased year by year,with a particularly rapid increase after 2015.Institutions and researchers from China and the USA publish the greatest number of papers and contribute the most to this field.By analyzing the research progress in this field,we also find that the protection and restoration of freshwater aquaculture environments has received attention since as early as 1990,such as the application of constructed wetlands and recirculating aquaculture systems.Recently,researchers have increasingly focused on the use of microbial communities in remediation.Furthermore,vanRijn,J's papers are of great value to the research in this field.In content analysis,the application of primary technologies,including plant selection,aquatic animals,microorganisms,and biological filtration and purification equipment,as well as ecological engineering technologies with combinations of various types of organisms,is described to improve the effectiveness and efficiency of remediation.The performance,advantages,disadvantages,or limitations and prospects of these technology applications are analyzed in detail.By comparison,ecological engineering is shown to be the best remediation technology,being most comprehensive,and well-established.Taken together,this paper composes and summarizes existing work in this field,and provides guidance for future research on the improvement of existing technologies and the development of new technologies,with the aim of enhancing remediation capability,improving ecological sustainability and ensuring economic viability.展开更多
The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC...The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC.Microcystic aeruginosa FACHB-524 and plaque purification were used to isolate individual cyanophages,and culturing MaMV-DC with cyanobacteria allowed us to prepare purified cyanophages for further analysis.Electron microscopy demonstrated that the negatively stained viral particles are tadpole-shaped with an icosahedral head approximately 70 nm in diameter and a contractile tail approximately 160 nm in length.Using one-step growth experiments,the latent period and burst size of MaMV-DC were estimated to be 24–48 hours and approximately 80infectious units per cell,respectively.Restriction endonuclease digestion and agarose gel electrophoresis were performed using purified MaMV-DC genomic DNA,and the genome size was estimated to be approximately 160 kb.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)analysis revealed four major structural proteins.These results support the growing interest in using freshwater cyanophages to control bloom-forming cyanobacterium.展开更多
Grass carp plays an important role in small-scale aquaculture in Vietnam. However, a severe disease, known in Vietnam as "Red Spot Disease", is causing significant economic loss in grass carp aquaculture. In...Grass carp plays an important role in small-scale aquaculture in Vietnam. However, a severe disease, known in Vietnam as "Red Spot Disease", is causing significant economic loss in grass carp aquaculture. In this study, the tissue samples isolated from the grass carp with Red Spot Disease in Vietnam are investigated and comparied with the control GCHV isolated in China by experimental infection, culture cell infection, serological cross reactivity, and RT-PCR amplification. Infected grass carp exhibits hemorrhage symptoms about 5 days after experimental injection with GCHV-V (Vietnam) strain. The symptoms and lethality induced by the GCHV-V strain are identical to that induced by the Chinese GCHV-9014 strain. The Chinese GCHV-873 strain induces typical cytopathogenic effects in 4 cell lines, such as CIK, CAB, FHM and GCO, from the 6 fish cell lines examined. No cytopathogenic effects are observed in all the 6 examined cell lines, including CAB, FHM, CIK, EPC, CCO and GCO, infected by the GCHV-V strain and GCHV-9014 strain. Immunodiffusion assays demonstrate an obvious cross-reactivity among three GCHV strains. Precipitin lines are clearly observed not only between the anti-GCHV-873 serum and the two strains GCHV-873 and GCHV-9014, but also between the anti-GCHV-873 serum and the GCHV-V strain. GCHV can be detected by immunodiffusion assays after three generations of blind propagations in the cell lines inoculated by GCHV-V strain. This implicates that GCHV-V viruses have been replicated and amplified despite there being no cytopathogenic effects observed in these examined cell lines. Three genome segments of GCHV, including S8, S9 and S10, are amplified by three sets of PCR primers designed according to the segment sequences published recently. The Q8fp and Q8rp primer set specific for genome segment S8 amplifies a 955 bp fragment from the extracted sample of diseased fish with Red Spot Disease, and the fragment size is identical to that amplified by the same primer set from control GCHV-873 strain. Simultaneously, the Q9fp and Q9rp primer set specific for genome segment S9 generates a same 635 bp product, and the Q10fp and Q10rp primer set specific for genome segment S10 produces a same 697 bp fragment from both template samples of diseased fish with Red Spot Disease and control GCHV-873 strain. The RT-PCR amplification and corresponding size comparison data indicate that the three GCHV-V genome segments extracted from the diseased grass carp with Red Spot Disease in Vietnam should be identical to that in control GCHV-873 strain from China. The data confirm that the causative agent of grass carp Red Spot Disease in Vietnam is a virus, and the virus is closely similar to GCHV strain in China.展开更多
Spatial distribution and abundance of small fishes were studied in autumn 2007 in the Xiaosihai Lake, a shallow lake along the middle reach of the Changjiang (Yangtze) River. Based on the plant cover, the lake was div...Spatial distribution and abundance of small fishes were studied in autumn 2007 in the Xiaosihai Lake, a shallow lake along the middle reach of the Changjiang (Yangtze) River. Based on the plant cover, the lake was divided into three major habitats: Myriophyllum spicatum habitat (MS habitat), Trapa bispinosa habitat (TB habitat), and non-vegetation habitat (NV habitat). A modified pop-net was used for quantitative sampling of small fishes in the three habitats, and the Zippin’s removal method was used for estimating densities of the small fishes. A total of 13 species belonging to 5 families were collected, with 11 species in MS habitat, 7 species in TB habitat, and 5 species in NV habitat. Habitat type had significant effect on the spatial distribution of small fishes. The Shannon-Wiener diversity index in the MS, TB and NV habitats were 1.28, 0.56 and 0.54, respectively. The total density and biomass of small fishes were significantly higher in the MS habitat (13.68 ind/m2 and 4.44 g/m2) than in the TB habitat (1.41 ind/m2 and 0.54 g/m2) and the NV habitat (1.08 ind/m2 and 0.40 g/m2), and were not significantly different between the TB habitat and the NV habitat. Water depth had no significant effect on spatial distribution of the small fishes. It was suggested that vegetation type played an important role in habitat selectivity of small fishes, and the presence of submersed vegetation should be of significance in the conservation of small fish diversity.展开更多
In this paper,sinking and growth of apexes and mid-stems of Myriophyllum spicatum L.,Hydrilla verticillata (L.f.) Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were inve...In this paper,sinking and growth of apexes and mid-stems of Myriophyllum spicatum L.,Hydrilla verticillata (L.f.) Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were investigated. Sinking rates of apexes and mid-stems reached 34.8% and 4.4% at the 6 th day and 91.1% and 66.7% at the 22 nd day for M. spicatum,57.8% and 55.6% at the 6 th day and 100% and 97.8% at the 22 nd day for H. verticillata,18.9% and 86.7% at the 6 th day and 95.6% and 100% at the 22 nd day for C. demersum,respectively. Most sunken fragments established themselves successfully with significant growth. Total shoot length of plantlets developed from apexes and mid-stems increased by 399% and 61% for M. spicatum,593% and 256% for H. verticillata and 114% and 104% for C. demersum,respectively. The results showed that it was feasible to establish submersed macrophytes via sinking and colonization of shoot fragments clipped off manually.展开更多
Microcystis often dominates phytoplankton in eutrophic lakes and must survive a long period of cold or dark conditions.However,the survival strategies of Microcystis to withstand cold or dark stress are less well know...Microcystis often dominates phytoplankton in eutrophic lakes and must survive a long period of cold or dark conditions.However,the survival strategies of Microcystis to withstand cold or dark stress are less well known.In this study,we conducted experiments on the responses of two toxic Microcystis aeruginosa strains(FACHB-905 and FACHB-915) and their microcystin release in conditions of low temperature(15℃ or 4℃,with illumination) or darkness,and subsequent recovery in standard conditions(25℃ with illumination).On exposure to 15℃,a small decrease in cell viability was observed,but the cell number increased gradually,suggesting that M.aeruginosa FACHB-905 and FACHB-915 cells seem in general tolerant in 15℃.Interestingly,our results show that a higher carotenoid content and microcystin release potentially enhance the fitness of surviving cells at 15℃.M.aeruginosa cells exposed to lower temperature light stress(4℃) did not completely lose viability and retained the ability to reinitiate growth.In darkness,the maximum quantum yield(F_v/F_m) and the maximum electron transport rate(ETR_(max)) values and cell viability of M.aeruginosa cells gradually decreased with time.During the recovery period,the photosynthetic efficiency of M.aeruginosa reverted to the normal level.Additionally,M.aeruginosa FACHB-905 and FACHB-915 exposed to low temperature had increased caspase-3-like activity and DNA fragmentation,which suggests the occurrence of a type of cell death in M.aeruginosa cells under cold stress similar to programmed cell death.Overall,our findings could confer certain advantages on the Microcystis for surviving cold or dark conditions encountered in the annual cycle,and help explain its repeated occurrence in water blooms in large and shallow lakes.展开更多
We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of t...We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang(Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns dif fered in the two lakes and were af fected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish >45 cm(smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes.展开更多
The Asian swamp eel(Monopterus albus) is one of the most economically important freshwater fish in East Asia,but data on the immune genes of M.albus are scarce compared to other commercially important fish.A better un...The Asian swamp eel(Monopterus albus) is one of the most economically important freshwater fish in East Asia,but data on the immune genes of M.albus are scarce compared to other commercially important fish.A better understanding of the eel's immune responses may help in developing strategies for disease management,potentially improving yields and mitigating losses.In mammals,interferon regulatory factors(IRFs) play a vital role in both the innate and adaptive immune system; though among teleosts IRF4 and IRF10 have seldom been studied.In this study,we characterized IRF4 and IRF10 from M.albus(maIRF4 and maIRF10) and found that maIRF4 cDNA consists of 1 716 nucleotides encoding a 451 amino acid(aa) protein,while maIRF10 consists of 1 744 nucleotides including an open reading frame(ORF) of 1 236 nt encoding 411 aa.The maIRF10 gene was constitutively expressed at high levels in a variety of tissues,while maIRF4 showed a very limited expression pattern.Expression of maIRF4 and maIRF10 in head kidney,and spleen tissues was significantly up-regulated from 12 h to 48 h post-stimulation with polyinosinic: polycytidylic acid(poly I:C),lipopolysaccharide(LPS) and a common pathogenic bacteria Aeromonas hydrophila.These results suggest that IRF4 and IRF10 play roles in immune responses to both viral and bacterial infections in M.albus.展开更多
Mauremys mutica(Cantor,1842)is an endangered species in China.Main phenotypic variations inbody color,body weight,body shape,clutch size,egg size,and hatchling size were revealed betweenthe southern and northern popul...Mauremys mutica(Cantor,1842)is an endangered species in China.Main phenotypic variations inbody color,body weight,body shape,clutch size,egg size,and hatchling size were revealed betweenthe southern and northern populations.Both populations have the phenomenon of'larger male'sexualsize dimorphism(SSD),especially in the southern population.Furthermore,genetic variations betweenthe two populations were analyzed by RAPD band patterns of 30 random individuals in each population.The average genetic distance was 0.299±0.108 among the samples of two populations.The average ge-netic distance between southern and northern populations was 0.305±0.046.Cluster analysis indicatedthat all the individuals from the southern and northern populations were clustered among themselves toform two distinct clades.A total of 20 population-specific RAPD fragments were scored from 16 primers,and could be used as RAPD markers for distinguishing the southern and the northern population.Basedon the nucleotide sequences of two RAPD markers,two pairs of SCAR primers(SC1-S and SC2-S)weredesigned,which could be used as SCAR markers for the southern population.According to the significantphenotypic and genetic variations,we suggested that the northern population and southern populationmight be considered as two separate taxa,the'northern taxon'and the'southern taxon',and the con-servation should be respectively conducted on the two taxa.展开更多
基金supported by the National Natural Science Foundation of China (32170480,31972866)Youth Innovation Promotion Association,Chinese Academy of Sciences (http://www.yicas.cn)+1 种基金Young Top-notch Talent Cultivation Program of Hubei ProvinceWuhan Branch,Supercomputing Center,Chinese Academy of Sciences,China。
文摘Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments.After a period of dormancy,organisms often exhibit exceptional resilience.This period is typically divided into hibernation and aestivation based on seasonal patterns.However,the mechanisms by which organisms adapt to their environments during dormancy,as well as the potential relationships between different states of dormancy,deserve further exploration.Here,we selected Perccottus glenii and Protopterus annectens as the primary subjects to study hibernation and aestivation,respectively.Based on histological and transcriptomic analysis of multiple organs,we discovered that dormancy involved a coordinated functional response across organs.Enrichment analyses revealed noteworthy disparities between the two dormant species in their responses to extreme temperatures.Notably,similarities in gene expression patterns pertaining to energy metabolism,neural activity,and biosynthesis were noted during hibernation,suggesting a potential correlation between hibernation and aestivation.To further explore the relationship between these two phenomena,we analyzed other dormancy-capable species using data from publicly available databases.This comparative analysis revealed that most orthologous genes involved in metabolism,cell proliferation,and neural function exhibited consistent expression patterns during dormancy,indicating that the observed similarity between hibernation and aestivation may be attributable to convergent evolution.In conclusion,this study enhances our comprehension of the dormancy phenomenon and offers new insights into the molecular mechanisms underpinning vertebrate dormancy.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA24010108)National Natural Science Foundation of China(31872554,32172952)Project from the State Key Laboratory of Freshwater Ecology and Biotechnology(2019FBZ05)。
文摘Stearyl coenzyme A desaturase(SCD), also known as delta-9 desaturase, catalyzes the rate-limiting step in the formation of monounsaturated fatty acids.In mammals, depletion or inhibition of SCD activity generally leads to a decrease in triglycerides and cholesteryl esters. However, the endogenous role of scd in teleost fish remains unknown. Here, we generated a zebrafish scd mutant(scd-/-) to elucidate the role of scd in lipid metabolism and sexual development. Gas chromatography-mass spectrometry(GC-MS) showed that the scd-/- mutants had increased levels of saturated fatty acids C16:0 and C18:0, and decreased levels of monounsaturated fatty acids C16:1 and C18:1. The mutant fish displayed a short stature and an enlarged abdomen during development. Unlike Scd-/ -mammals, the scd-/- zebrafish showed significantly increased fat accumulation in the whole body,especially in the liver, leading to hepatic mitochondrial dysfunction and severe cell apoptosis.Mechanistically, srebf1, a gene encoding a transcriptional activator related to adipogenesis,acc1 and acaca, genes involved in fatty acid synthesis, and dgat2, a key gene involved in triglyceride synthesis, were significantly upregulated in mutant livers to activate fatty acid biosynthesis and adipogenesis. The scd-/- males exhibited defective natural mating behavior due to defective genital papillae but possessed functional mature sperm. All defects in the scd-/- mutants could be rescued by ubiquitous transgenic overexpression of scd. In conclusion, our study demonstrates that scd is indispensable for maintaining lipid homeostasis and development of secondary sexual characteristics in zebrafish.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)。
文摘Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We recently identified zona pellucida(Zp) as the top differentially expressed protein between East Asian cyprinids that produce adhesive and semi-buoyant eggs,suggesting that Zp protein may play important roles in the regulation of egg type.In this work,we generated transgenic zebrafish in which oocyte-specific expression of zp genes from rare minnow(Gobiocypris rarus),an East Asian cyprinid laying adhesive eggs,was driven by a zebrafish zp3.2 gene promoter.We found that the transgenic eggs obtained partial adhesiveness and exhibited alteration in hydration and buoyancy.Abnormal metabolism of vitellogenin(VTG) may contribute to enhanced hydration and/or buoyancy.Our work shows that expression of the exogenous zp3a gene from an adhesiveegg producing fish is sufficient to induce changes in both egg adhesiveness and buoyancy in zebrafish,emphasizing the important role of zp genes in the regulation of spawning habits.Our results thus provide new insights into how endemic East Asian cyprinids may have adapted to the Yangtze river-lake system via changes in spawning habits.
基金Supported by the National Natural Science Foundation of China (No.90411018,30270036) and by the Chinese Academy of Sciences
文摘The physiological responses of Nitzschia palea Kützing,a freshwater diatom,to elevated CO2 were investigated and compared with those of a marine diatom,Chaetoceros muelleri Lemmermann previously reported.Elevated CO_2 concentration to 700μl/L increased the dissolved inorganic carbon (DIC) and lowered the pH in the cultures of N.palea,thus enhancing the growth by 4%-20% during the whole growth period.High CO2-grown N.palea cells showed lower levels of dark respiration rates and higher I_k values.Light-saturated photosynthetic rates and photosynthetic efficiencies decreased in N. palea with the doubling CO_2 concentration in airflow to the bottom of cultures,although the doubling CO_2 concentration in airflow to the surface cultures had few effects on these two photosynthetic parameters.N.palea cells were found to be capable of using HCO_3^-in addition to gaseous CO_2,and the CO_2 enrichment decreased their affinity for HCO_3^-and CO_2.Although doubled CO_2 level would enhance the biomass of N.palea and C.muelleri to different extents,compared with the marine diatom,it had a significant effect on the specific growth rates of N.palea.In addition,the responses of photosynthetic parameters of N.palea to doubled CO:concentration were almost opposite to those of C.muelleri.
基金Supported by the National Major Technology Projects of Water Pollution Control and Management(No.2012ZX07105-004)the National Natural Science Foundation of China(Nos.41173118,40703017,40873079)
文摘A comprehensive study of the invasive icefish Neosalanx taihuensis feeding ecology in Erhai Lake was conducted from November 2009 to October 2010. Prey items in the guts of the icefish sampled varied significantly according to season. This finding suggests a relationship between fluctuations in available prey in the environment and selective feeding by icefish. N. taihuensis preferred large-sized zooplankton,such as Daphnia and calanoids. Additionally,the gut fullness values differed significantly( P <0.001) among sampling times. To compare the values at different times,samples were taken over a 24 h period every 2 months for the entire year. The feeding activities of the fish were concentrated either in the morning(8:00) and/or at dusk(20:00),except in September 2010. This finding can be explained primarily by the variation in optimum light intensity. Daily N. taihuensis zooplankton consumption varied significantly,both diurnally and among seasons. The daily consumption values ranged from 0.089 to 0.237 g(wet weight) per 100 g wet fish weight in temperatures between 11.50°C and 24.68°C. This is the first report of diel feeding periodicity and daily food consumption of icefish in their invaded ecosystems.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Precision Seed Design and Breeding,XDA24010108)National Natural Science Foundation of China(31972780&31721005)+1 种基金National Key R&D Program of China(2018YFA0801000)State Key Laboratory of Freshwater Ecology and Biotechnology(2019FBZ05)。
文摘Omega-3 polyunsaturated fatty acids(n-3 PUFAs),particularly docosahexaenoic acid(22:6n-3,DHA),play crucial roles in the reproductive health of vertebrates,including humans.Nevertheless,the underlying mechanism related to this phenomenon remains largely unknown.In this study,we employed two zebrafish genetic models,i.e.,elovl2^(-/-)mutant as an endogenous DHAdeficient model and fat1(omega-3 desaturase encoding gene)transgenic zebrafish as an endogenous DHA-rich model,to investigate the effects of DHA on oocyte maturation and quality.Results show that the elovl2^(-/-)mutants had much lower fecundity and poorer oocyte quality than the wild-type controls,while the fat1 zebrafish had higher fecundity and better oocyte quality than wildtype controls.DHA deficiency in elovl2^(-/-)embryos led to defects in egg activation,poor microtubule stability,and reduced pregnenolone levels.Further study revealed that DHA promoted pregnenolone synthesis by enhancing transcription of cyp11a1,which encodes the cholesterol side-chain cleavage enzyme,thereby stabilizing microtubule assembly during oogenesis.In turn,the hypothalamic-pituitary-gonadal axis was enhanced by DHA.In conclusion,using two unique genetic models,our findings demonstrate that endogenously synthesized DHA promotes oocyte maturation and quality by promoting pregnenolone production via transcriptional regulation of cyp11a1.
基金supported by the National Key Research and Development Program,China (2022YFF1000300 to Z.Y.and2022YFD2401800 to G.Z.)Pilot Program A Project from the Chinese Academy of Sciences (XDA24010206 to Z.Y.)+3 种基金Foundation of Hubei Hongshan Laboratory (2021hskf013 to G.Z.and 2021hszd021 to Z.Y.)National Natural Science Foundation of China (31972779 to G.Z.)Youth Innovation Promotion Association of CAS (2020336 to G.Z.)State Key Laboratory of Freshwater Ecology and Biotechnology (2016FBZ05 to Z.Y.)。
文摘Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males.However,the mechanisms by which testosterone acts on lipid metabolism are not yet fully understood,especially in teleosts.In this study,cyp17a1-/-zebrafish(Danio rerio)exhibited excessive visceral adipose tissue(VAT),lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis(DNL)enzymes.The assay for transposase accessible chromatinwithsequencing(ATAC-seq)results demonstrated that chromatin accessibility of DNL genes was increased in cyp17a1-/-fish compared to cyp17a1+/+male fish,including stearoyl-CoA desaturase(scd)and fatty acid synthase(fasn).Androgen response element(ARE)motifs in the androgen signaling pathway were significantly enriched in cyp17a1+/+male fish but not in cyp17a1-/-fish.Both androgen receptor(ar)-/-and wildtype(WT)zebrafish administered with Ar antagonist flutamide displayed excessive visceral adipose tissue,lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis enzymes.The Ar agonist BMS-564929 reduced the content of VAT and lipid content,and down-regulated acetyl-CoA carboxylase a(acaca),fasn,and scd expression.Mechanistically,the rescue effect of testosterone on cyp17a1-/-fish in terms of phenotypes was abolished when ar was additionally depleted.Collectively,these findings reveal that testosterone inhibits lipid deposition by down-regulating DNL genes via Ar in zebrafish,thus expanding our understanding of the relationship between testosterone and lipid metabolism in teleosts.
基金supported by the High-Tech Research Program (863) of China (No.2009ZX07106-002-004)the National Natural Science Foundation of China (No.30870221,20877093,50808172, 50909091)
文摘Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total suspended solids,Chlorophyll a and Secchi transparency in the water column was found,while levels of water depth,electrical conductivity,total dissolved solids and NO 3--N concentration increased markedly post-dredging.The effects of dredging on dissolved oxygen,pH value and temperature were almost negligible.The zooplankton community structure responded rapidly to the environmental changes caused mainly by dredging.As a result,the abundance of rotifers decreased,while the density of zooplanktonic crustaceans increased markedly.The representative taxa were Brachionus angularis,B.budapestinensis,B.diversicornis,Synchaeta spp.and Neodiaptomus schmackeri.A distinct relationship between zooplankton taxa composition and their environment,unraveled by a redundancy analysis,indicating that the measured environment contributed to the variations in the zooplankton community structure to some extent.The first four synthetic environmental variables explained 51.7% of the taxonomic structure.Therefore,with the reduction of internal nutrient load and a shift in dominance by less eutrophic species,it inferred that dredging might be one of effective measures for environmental improvements of such lakes.
基金supported by the National Natural Science Foundation of China (No.30870221,20877093,50808172)the High Technology Research and Development Program (863) of China (No.2009X207209-004)
文摘Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid (PLFA) composition. A total of 20 fatty acids in the range of C11 to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in different media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant differences among the eight different media by Tukey's honestly test. It was found that steel slag was significantly different in the microbial community as compared to other filter media, probably due to its alkaline efluent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis (PCA) showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.
基金the National Natural Science Foundation of China(grant numbers 32173027 and U20A2010).
文摘Freshwater aquaculture plays an important role in the global aquaculture industry.The success of freshwater aquaculture relies on the integration of bio-ecological remediation technologies to ensure its sustainable development.This paper systematically reviews the global literatures on bio-ecological remediation of freshwater aquaculture environments from 1990 to 2021,and discusses in detail the research progress and status quo in this field using both bibliometric analysis and content analysis.Our results indicate that the number of publications per year has increased year by year,with a particularly rapid increase after 2015.Institutions and researchers from China and the USA publish the greatest number of papers and contribute the most to this field.By analyzing the research progress in this field,we also find that the protection and restoration of freshwater aquaculture environments has received attention since as early as 1990,such as the application of constructed wetlands and recirculating aquaculture systems.Recently,researchers have increasingly focused on the use of microbial communities in remediation.Furthermore,vanRijn,J's papers are of great value to the research in this field.In content analysis,the application of primary technologies,including plant selection,aquatic animals,microorganisms,and biological filtration and purification equipment,as well as ecological engineering technologies with combinations of various types of organisms,is described to improve the effectiveness and efficiency of remediation.The performance,advantages,disadvantages,or limitations and prospects of these technology applications are analyzed in detail.By comparison,ecological engineering is shown to be the best remediation technology,being most comprehensive,and well-established.Taken together,this paper composes and summarizes existing work in this field,and provides guidance for future research on the improvement of existing technologies and the development of new technologies,with the aim of enhancing remediation capability,improving ecological sustainability and ensuring economic viability.
基金National Natural Science Foundation of China(grant nos.31072239,31270213)Knowledge Innovation Program of the Chinese Academy of Sciences(grant no.KSCX2-EW-Z-3)StateKey Laboratory of Freshwater Ecology&Biotechnology Program(grant no.2011FBZ12)
文摘The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC.Microcystic aeruginosa FACHB-524 and plaque purification were used to isolate individual cyanophages,and culturing MaMV-DC with cyanobacteria allowed us to prepare purified cyanophages for further analysis.Electron microscopy demonstrated that the negatively stained viral particles are tadpole-shaped with an icosahedral head approximately 70 nm in diameter and a contractile tail approximately 160 nm in length.Using one-step growth experiments,the latent period and burst size of MaMV-DC were estimated to be 24–48 hours and approximately 80infectious units per cell,respectively.Restriction endonuclease digestion and agarose gel electrophoresis were performed using purified MaMV-DC genomic DNA,and the genome size was estimated to be approximately 160 kb.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)analysis revealed four major structural proteins.These results support the growing interest in using freshwater cyanophages to control bloom-forming cyanobacterium.
基金This research was supported by National 863 High Technology Research Foundation of China(2002AA62601)National Natural Science Foundation of China(30170726)+1 种基金the Project of Chinese Academy of Sciences(KSCXZ-SW-302)the Innovation Project of the Institute of Hydrobiology,Chinese Academy of Sciences.
文摘Grass carp plays an important role in small-scale aquaculture in Vietnam. However, a severe disease, known in Vietnam as "Red Spot Disease", is causing significant economic loss in grass carp aquaculture. In this study, the tissue samples isolated from the grass carp with Red Spot Disease in Vietnam are investigated and comparied with the control GCHV isolated in China by experimental infection, culture cell infection, serological cross reactivity, and RT-PCR amplification. Infected grass carp exhibits hemorrhage symptoms about 5 days after experimental injection with GCHV-V (Vietnam) strain. The symptoms and lethality induced by the GCHV-V strain are identical to that induced by the Chinese GCHV-9014 strain. The Chinese GCHV-873 strain induces typical cytopathogenic effects in 4 cell lines, such as CIK, CAB, FHM and GCO, from the 6 fish cell lines examined. No cytopathogenic effects are observed in all the 6 examined cell lines, including CAB, FHM, CIK, EPC, CCO and GCO, infected by the GCHV-V strain and GCHV-9014 strain. Immunodiffusion assays demonstrate an obvious cross-reactivity among three GCHV strains. Precipitin lines are clearly observed not only between the anti-GCHV-873 serum and the two strains GCHV-873 and GCHV-9014, but also between the anti-GCHV-873 serum and the GCHV-V strain. GCHV can be detected by immunodiffusion assays after three generations of blind propagations in the cell lines inoculated by GCHV-V strain. This implicates that GCHV-V viruses have been replicated and amplified despite there being no cytopathogenic effects observed in these examined cell lines. Three genome segments of GCHV, including S8, S9 and S10, are amplified by three sets of PCR primers designed according to the segment sequences published recently. The Q8fp and Q8rp primer set specific for genome segment S8 amplifies a 955 bp fragment from the extracted sample of diseased fish with Red Spot Disease, and the fragment size is identical to that amplified by the same primer set from control GCHV-873 strain. Simultaneously, the Q9fp and Q9rp primer set specific for genome segment S9 generates a same 635 bp product, and the Q10fp and Q10rp primer set specific for genome segment S10 produces a same 697 bp fragment from both template samples of diseased fish with Red Spot Disease and control GCHV-873 strain. The RT-PCR amplification and corresponding size comparison data indicate that the three GCHV-V genome segments extracted from the diseased grass carp with Red Spot Disease in Vietnam should be identical to that in control GCHV-873 strain from China. The data confirm that the causative agent of grass carp Red Spot Disease in Vietnam is a virus, and the virus is closely similar to GCHV strain in China.
基金Supported by the National Natural Science Foundation of China (Nos. 30571440, 30830025)The National Key Technology R&D Program (No. 2007BAD37B03)the National Basic Research Program of China (973 Program) (No. 2007CB109205)
文摘Spatial distribution and abundance of small fishes were studied in autumn 2007 in the Xiaosihai Lake, a shallow lake along the middle reach of the Changjiang (Yangtze) River. Based on the plant cover, the lake was divided into three major habitats: Myriophyllum spicatum habitat (MS habitat), Trapa bispinosa habitat (TB habitat), and non-vegetation habitat (NV habitat). A modified pop-net was used for quantitative sampling of small fishes in the three habitats, and the Zippin’s removal method was used for estimating densities of the small fishes. A total of 13 species belonging to 5 families were collected, with 11 species in MS habitat, 7 species in TB habitat, and 5 species in NV habitat. Habitat type had significant effect on the spatial distribution of small fishes. The Shannon-Wiener diversity index in the MS, TB and NV habitats were 1.28, 0.56 and 0.54, respectively. The total density and biomass of small fishes were significantly higher in the MS habitat (13.68 ind/m2 and 4.44 g/m2) than in the TB habitat (1.41 ind/m2 and 0.54 g/m2) and the NV habitat (1.08 ind/m2 and 0.40 g/m2), and were not significantly different between the TB habitat and the NV habitat. Water depth had no significant effect on spatial distribution of the small fishes. It was suggested that vegetation type played an important role in habitat selectivity of small fishes, and the presence of submersed vegetation should be of significance in the conservation of small fish diversity.
基金Supported by the National Natural Science Foundation of China (39925007)the High Technology Research and Development Program of China (2002AA60l021)the Knowledge Innovation Program Key Project of Chinese Academy of Sciences (KSCX2-SW-102)
文摘In this paper,sinking and growth of apexes and mid-stems of Myriophyllum spicatum L.,Hydrilla verticillata (L.f.) Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were investigated. Sinking rates of apexes and mid-stems reached 34.8% and 4.4% at the 6 th day and 91.1% and 66.7% at the 22 nd day for M. spicatum,57.8% and 55.6% at the 6 th day and 100% and 97.8% at the 22 nd day for H. verticillata,18.9% and 86.7% at the 6 th day and 95.6% and 100% at the 22 nd day for C. demersum,respectively. Most sunken fragments established themselves successfully with significant growth. Total shoot length of plantlets developed from apexes and mid-stems increased by 399% and 61% for M. spicatum,593% and 256% for H. verticillata and 114% and 104% for C. demersum,respectively. The results showed that it was feasible to establish submersed macrophytes via sinking and colonization of shoot fragments clipped off manually.
基金Supported by the National Natural Science Foundation of China(Nos.31070355,31370418)
文摘Microcystis often dominates phytoplankton in eutrophic lakes and must survive a long period of cold or dark conditions.However,the survival strategies of Microcystis to withstand cold or dark stress are less well known.In this study,we conducted experiments on the responses of two toxic Microcystis aeruginosa strains(FACHB-905 and FACHB-915) and their microcystin release in conditions of low temperature(15℃ or 4℃,with illumination) or darkness,and subsequent recovery in standard conditions(25℃ with illumination).On exposure to 15℃,a small decrease in cell viability was observed,but the cell number increased gradually,suggesting that M.aeruginosa FACHB-905 and FACHB-915 cells seem in general tolerant in 15℃.Interestingly,our results show that a higher carotenoid content and microcystin release potentially enhance the fitness of surviving cells at 15℃.M.aeruginosa cells exposed to lower temperature light stress(4℃) did not completely lose viability and retained the ability to reinitiate growth.In darkness,the maximum quantum yield(F_v/F_m) and the maximum electron transport rate(ETR_(max)) values and cell viability of M.aeruginosa cells gradually decreased with time.During the recovery period,the photosynthetic efficiency of M.aeruginosa reverted to the normal level.Additionally,M.aeruginosa FACHB-905 and FACHB-915 exposed to low temperature had increased caspase-3-like activity and DNA fragmentation,which suggests the occurrence of a type of cell death in M.aeruginosa cells under cold stress similar to programmed cell death.Overall,our findings could confer certain advantages on the Microcystis for surviving cold or dark conditions encountered in the annual cycle,and help explain its repeated occurrence in water blooms in large and shallow lakes.
基金Supported by the Special Scientific Research Fund of Agriculture Public Welfare Profession of China(No.201303056)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2011FBZ28)the Science and Technology Research Project of China Three Gorges Corporation(No.CT-12-08-01)
文摘We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang(Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns dif fered in the two lakes and were af fected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish >45 cm(smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes.
基金financially supported by the Project from the National Natural Science Foundation of China(31101928)the State Key Laboratory of Freshwater Ecology and Biotechnology(2010FB02)Public Welfare Scientific Research Project of Hubei Province(2012DBA29001)
文摘The Asian swamp eel(Monopterus albus) is one of the most economically important freshwater fish in East Asia,but data on the immune genes of M.albus are scarce compared to other commercially important fish.A better understanding of the eel's immune responses may help in developing strategies for disease management,potentially improving yields and mitigating losses.In mammals,interferon regulatory factors(IRFs) play a vital role in both the innate and adaptive immune system; though among teleosts IRF4 and IRF10 have seldom been studied.In this study,we characterized IRF4 and IRF10 from M.albus(maIRF4 and maIRF10) and found that maIRF4 cDNA consists of 1 716 nucleotides encoding a 451 amino acid(aa) protein,while maIRF10 consists of 1 744 nucleotides including an open reading frame(ORF) of 1 236 nt encoding 411 aa.The maIRF10 gene was constitutively expressed at high levels in a variety of tissues,while maIRF4 showed a very limited expression pattern.Expression of maIRF4 and maIRF10 in head kidney,and spleen tissues was significantly up-regulated from 12 h to 48 h post-stimulation with polyinosinic: polycytidylic acid(poly I:C),lipopolysaccharide(LPS) and a common pathogenic bacteria Aeromonas hydrophila.These results suggest that IRF4 and IRF10 play roles in immune responses to both viral and bacterial infections in M.albus.
基金the National Basic Research Program of China(No.2004CB117405)the Key Research Program of Ocean and Fishery Bureau of Guangdong province(No.2001A09)
文摘Mauremys mutica(Cantor,1842)is an endangered species in China.Main phenotypic variations inbody color,body weight,body shape,clutch size,egg size,and hatchling size were revealed betweenthe southern and northern populations.Both populations have the phenomenon of'larger male'sexualsize dimorphism(SSD),especially in the southern population.Furthermore,genetic variations betweenthe two populations were analyzed by RAPD band patterns of 30 random individuals in each population.The average genetic distance was 0.299±0.108 among the samples of two populations.The average ge-netic distance between southern and northern populations was 0.305±0.046.Cluster analysis indicatedthat all the individuals from the southern and northern populations were clustered among themselves toform two distinct clades.A total of 20 population-specific RAPD fragments were scored from 16 primers,and could be used as RAPD markers for distinguishing the southern and the northern population.Basedon the nucleotide sequences of two RAPD markers,two pairs of SCAR primers(SC1-S and SC2-S)weredesigned,which could be used as SCAR markers for the southern population.According to the significantphenotypic and genetic variations,we suggested that the northern population and southern populationmight be considered as two separate taxa,the'northern taxon'and the'southern taxon',and the con-servation should be respectively conducted on the two taxa.
