Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass ...Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894＋ 1 006 indYL and 12.47± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella eochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature （R=0,209, P=0.003; R=0.446, P=0.000）, but the peak density showed two lags in response to chl a. According to the Jaccard similarity index （S0, the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H＇, Margalef richness index D and Pielou evenness index J were 1.96±0.34, 1.61±0.50 and 0.77±0.10, respectively. In all four areas of Yangcheng Lake, β- mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.展开更多
Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few s...Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. , Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively （ P 〈 0.05 ） which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, L galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment （2.70 kJ/m^2）, the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, L galbana and T. chuii in turn. Chlorella sp. , L galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.展开更多
The toxicity of seven major HAB （harmful algal bloom） species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense （AT-6, non-PSP producer）, Alexandrium lusitanicum, A...The toxicity of seven major HAB （harmful algal bloom） species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense （AT-6, non-PSP producer）, Alexandrium lusitanicum, Alexandrum tamarense （ATHK） and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P donghaiense, P. globosa, P. micans, A. tamarense （AT-6）, or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense （ATHK） has strong lethal effect on the rotifer with 48h LCs0 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P micans, A. tamarense （AT-6） and A. lusitanicum can be taken by the rotifers as food, but A. tamarense （ATHK） or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.展开更多
We evaluated the response of a rotifer community to environmental changes in five shallow lakes in the middle reach of the Changjiang （Yangtze） River in summer and autumn 2010. These five lakes differed in trophic s...We evaluated the response of a rotifer community to environmental changes in five shallow lakes in the middle reach of the Changjiang （Yangtze） River in summer and autumn 2010. These five lakes differed in trophic status and rotifer community structure. Twenty-nine rotifer species were collected, of which Keratella cochlearis, Polyarthra dolichoptera, and Trichocerca elongate were dominant. The mean density, Shannon-Wiener diversity, and equitability among the five lakes differed significantly （P〈0.05）. The mean rotifer density was positively correlated with trophic state. The diversity was higher in lakes with high macrophyte coverage. The composition of rotifer species was closely associated with the trophic gradient. Five environmental variables, Secchi depth, conductivity, TN, NHa-N, and TP, significantly affected the composition of rotifer species. Keratella quadrata, Brachionus calyciflorus, and B. forficula were more common in eutrophic conditions. Our results suggest that eutrophication has a significant influence on the rotifer community structure and highlight the potential for using rotifer community structure as an indicator of trophic status in subtropical lakes.展开更多
Maternal eff ects are one of the most interesting topics in evolutionary ecology as they can aff ect the rate of evolution and population dynamics by phenotypic manipulation of off spring related to fi tness. At prese...Maternal eff ects are one of the most interesting topics in evolutionary ecology as they can aff ect the rate of evolution and population dynamics by phenotypic manipulation of off spring related to fi tness. At present, studies examining the interaction between maternal environment eff ects and maternal age (birth order) eff ects are scarce. We designed an experiment to reveal whether environmentally induced maternal manipulation works equally on off spring across birth orders in rotifer Brachionus calycifl orus. In the experiment, newborn amictic mothers (F0) were cultured parallelly in low (LD) and high (HD) population density. Off spring (F1) of young (YF0) and old (OF0) mothers in both LD and HD groups were cultured under a crowded condition and the mixis ratios of both F1 and F2 were examined. Results show that F1 from HD-YF0 had a signifi cantly higher mixis ratio and those amictic ones produced daughters (F2 ) with higher mixis ratio in response to crowding than those from HD-OF0. In contrast, no such diff erences among F1 siblings were found in the LD-F0 group. Therefore, the eff ect of maternal age on the sexual propensity of the off spring can be aff ected independently by the maternal population density.展开更多
The composition and distribution of benthic, periphytic and planktonic rotifers in different habitatsin Krottensee were investigated. Sixty-five rotifer taxa were identified, their relative abundance estimated. Classi...The composition and distribution of benthic, periphytic and planktonic rotifers in different habitatsin Krottensee were investigated. Sixty-five rotifer taxa were identified, their relative abundance estimated. Classification of the data set by cluster analysis allowed the recognition of distinct habitat groupe con-fined to acid bog ponds, macrophytes, sediments, and open water. Five groups of rotifer taxa were identifiedon the basis of their habitat preferences and the occurrence of the taxa. Highest diversities were found onmacrophytes and in acid bog ponds.展开更多
Thirteen rotifer species belonging to the families Lepadellidae and Trichocercidae were studied taxonomically from nine water bodies in Turkey. Lepadella biloba is a new entry to the Turkish rotifer fauna. All species...Thirteen rotifer species belonging to the families Lepadellidae and Trichocercidae were studied taxonomically from nine water bodies in Turkey. Lepadella biloba is a new entry to the Turkish rotifer fauna. All species were drawn under a light microscope using a camera lucida.展开更多
Of more than 90 rotifer taxa found in Denghu Lake and its nearby ponds in Wuhan, Hubei,the following were new to science: Brachionus angularis pyriformis, B. a. donghuensis, B. (Schizocerca) brevispina, Anuraeopsis fi...Of more than 90 rotifer taxa found in Denghu Lake and its nearby ponds in Wuhan, Hubei,the following were new to science: Brachionus angularis pyriformis, B. a. donghuensis, B. (Schizocerca) brevispina, Anuraeopsis fissa donghuensis, A. f. pseudonavicula, Mytilina ventralis Wuhanensis and Trichocerca similis strumosa.展开更多
Objective:To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes.Methods:Susceptible laboratory-bred Biomphalaria alexandrina(B.alexandrina)snails were exposed to lab...Objective:To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes.Methods:Susceptible laboratory-bred Biomphalaria alexandrina(B.alexandrina)snails were exposed to lab-maintained rotifers;Philodinaspp.,two weeks before and after being infected with Schistosoma mansoni(S.mansoni)miracidia.The consequent histopathological impact on snail tissues and cercarial biology were investigated before and after emergence from snails.Results:Contamination of B.alexandrinasnails with philodina,two weeks before miracidial exposure,was found to hinder the preliminary development of S.mansonicercariae inside the snail tissues.Furthermore,when snails were contaminated with rotifers two weeks post miracidial exposure;growth of already established cercariae was found to be retarded.The consequent influence of internalized rotifers within the snail tissue was clearly reflected on cercarial em ergence,activity and infectivity along the four weeks duration of shedding.In the present study,comparison of snail histopathological findings and altered cercarial biology observed between the experimental and control groups indicated that the rotifers may have affected the levels of snail's energy reservoirs,which eventually was found to have had an adverse impacton reproduction,growth and survival of the parasite within the snail host,coupled with its performance outside the snail.Conclusions:In future biological control strategies of schistosomiasis,ritifers should be considered as a parasitic scourge of humanity.展开更多
The effect of UV-B radiation enhancement at experimental doses of 0.00,0.24,0.48,0.72,0.96,and 1.20 kJ/m 2 on the population dynamics of the rotifer Brachionus urceus feeding on the alga Chlorella sp.was studied under...The effect of UV-B radiation enhancement at experimental doses of 0.00,0.24,0.48,0.72,0.96,and 1.20 kJ/m 2 on the population dynamics of the rotifer Brachionus urceus feeding on the alga Chlorella sp.was studied under controlled laboratory conditions using clonal culture and life-table techniques.The results show that UV-B radiation treatment significantly shortened the survival time of the rotifer （P 0.05）： The longest survival time （336 h） occurred in the control （0.00 kJ/m 2 ） while the shortest （222 h） occurred when exposed to the highest UV-B radiation treatment （1.20 kJ/m 2 ）.The fecundity of the rotifer B.urceus was enhanced by the lower UV-B radiation treatment （0.24 and 0.48 kJ/m 2 ） but inhibited by the higher treatments （0.96 and 1.20 kJ/m 2 ）.Life expectancy also was obviously affected by UV-B radiation （P 0.05）.The highest life expectancy occurred in the control （0.00 kJ/m 2 ）,and it became shorter with increasing doses of UV-B radiation.The resutls in the present study indicate that the life expectancy of the rotifer B.urceus can be used as an indicator for UV-B radiation enhancement.展开更多
A new freshwater rotifer Cephalodella changdensis sp.nov.discovered in two locations in Changde,Hunan,China,is described morphologically.The new species is characterized by body shape moderately elongate,double eyespo...A new freshwater rotifer Cephalodella changdensis sp.nov.discovered in two locations in Changde,Hunan,China,is described morphologically.The new species is characterized by body shape moderately elongate,double eyespots frontally,toes conical and almost straight,about one fourth of total length,trophi type B(classification after Wulfert,1937),rami asymmetrical with a pair of long alulae,fulcrum inverted T-shaped(ventral/dorsal view)with dorsally directed distal projection(lateral view),and manubria asymmetrical,left one slightly longer and stronger,with J-shaped or crutch-shaped posterior ends.展开更多
Planktonic rotifers were examined from April to October 2007 in two ponds created by sand extraction: Hubertus III (infrequently used for recreation)—pond I and Stawiki (commonly used for recreation)—pond II. The po...Planktonic rotifers were examined from April to October 2007 in two ponds created by sand extraction: Hubertus III (infrequently used for recreation)—pond I and Stawiki (commonly used for recreation)—pond II. The ponds are located within the protected Landscape Complex “Szopienice-Borki” in Silesian Upland (SW Poland). A total number of 58 taxa of rotifers were noted. The number of rotifer species and their densities were smaller in pond I than in pond II. In pond I, Polyarthra species were the most abundant, accounting for 48% of total rotifer density, whereas in pond II, Keratella cochlearis reached the highest density (accounting for 36% of total density). Analysis of variance (ANOVA) revealed a significant difference between communities of rotifers in species diversity (F = 5.88, p = 0.02) and species richness (F = 5.57, p = 0.03). The research proved that the pond commonly used for recreation (pond II) is characterized by a higher trophic state. Results of this study indicate that the methods and range of use of water bodies by humans have an important influence on the species richness and diversity of communities of planktonic rotifers.展开更多
Rotifers are considered as one of the most important prey organisms in the culture of altricial fish larvae. However, high density rotifer culture is often problematic due to water quality problems which results in fr...Rotifers are considered as one of the most important prey organisms in the culture of altricial fish larvae. However, high density rotifer culture is often problematic due to water quality problems which results in frequent crashes. In the present study, the performance of a small-scale, continuous system was evaluated for culturing rotifers, Brachionus plicatilis, using concentrated nonviable green algae, Nannochloropsis oculeataas feed in a 160 L tank for a period of 90 days. The system configuration was simple and major components consisted of a protein skimmer and a pure oxygen delivery system. Although egg ratio increased from 3% on day 1 to 21.8% and 39.3% on days 7 and 9, respectively, rotifer growth was slow at start up and resulted in fluctuations in total number of rotifers between days 19-41. Rotifer densities remained 〈 400 until day 51 but increased at higher rates reaching 900 individuals/mL on day 55, 1,620 on day 60 and 2,127 on day 70. Rotifer density reached a maximum of 2,188 individuals/mL on day 85. Once the rotifer density exceeded 1,500 individuals/mL （day 60）, periodical harvesting （a total of 16 harvest events） produced a total of 369,920,000 rotifers corresponding to a daily production of 12,330,667 individuals/day during the next 30 days until the experiment was terminated at day 90. As a result of periodic harvesting, water makeup and continuous protein skimming, total settleable solids and NH3-N levels remained low and ranged between 4-22 mL/L and 0.4-2.2 mg/L, respectively. The authors＇ findings indicated that this inexpensive culture system can be successfully used for small-scale marine or freshwater ornamental fish production. Further work is required to minimize lag period at start-up and increase the production potential and yield by better management of suspended solids.展开更多
The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and...The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and manage this ecosystem is vital. The aim of this work is to study the physicochemical parameters of the environment that influence the diversity and spatiotemporal distribution of Cladocerans and Rotifers in the mangrove waters of Mouanko. This study was carried out from November 2019 to October 2020 at 8 sampling stations. Both biological and physico-chemical sampling and analyses were done following standard recommendations. The results of the phyico-chemical analyses revealed that the waters of the Mouanko mangroves were slightly basic (7.64 ± 0.71 UC), moderately oxygenated (69.56% ± 14.29%) with low levels of nutrients [ NO <sup>-</sup>2</sub> (0. 06 ± 0.05 mg/L), NH<sup>+</sup>4</sub> (0.39 ± 0.3 mg/L) and PO<sup>3-</sup>4</sub> (up to 0.12 mg/L)] and high values of electrical conductivity (up to 6531.04 μS/cm), salinity (up to 3.71‰). 15 species of Cladocerans and 30 species of Rotifers were identified accounting for a total abundance of 612 ind/L. The species richness was higher in freshwater influenced zones (40 taxa) compared to marinewater influenced zones (17 taxa). Among these species, the Cladocera, Penilia avirostris was the most abundant in marinewater influenced zones (84 ind/L) while the Rotifer, Keratella tecta was the most abundant in freshwater influenced zones (64 ind/L). Shannon-Weaver’s diversity and Pielou’s equitability indices indicated that freshwater influenced zones host a diverse community with a tendency towards equi-partition of species while marinewater influenced zones revealed the opposite. The low levels of organic pollution indicator variables recorded and the high diversity of the freshwater influenced zones population studied attested to the low level of anthropization in this environment. High salinity and electrical conductivity values influence the distribution of these organisms.展开更多
Nanoplastics(less than 1µm in size,NPs)have emerged as a significant pollutant in aquatic environment,posing considerable threats to freshwater biota.However,the mechanisms through which NPs modulate the predatio...Nanoplastics(less than 1µm in size,NPs)have emerged as a significant pollutant in aquatic environment,posing considerable threats to freshwater biota.However,the mechanisms through which NPs modulate the predation responses of these organisms remain poorly elucidated.We investigated the impacts of polystyrene NPs,characterized by a representative particle size(diameter:50 nm;concentration:0–8μg/L),on the anti-predation defense mechanisms of mature rotifer Brachionus calyciflorus against predator of rotifer Asplanchna brightwellii,utilizing transcriptomics to unravel the underlying molecular pathways.Results reveal that the posterolateral spine length and type of B.calyciflorus serve as robust indicators of defensive morphology,even in the presence of NPs exposure.Specifically,increasing concentrations of NPs and predator cues suppressed the defensive responses,which was associated with morphological transformations.This suppression was associated with the down-regulation of the HIF-1αsignaling pathway,implicating potentially its role in modulating fight-or-flight responses.Furthermore,we identified functional crosstalk among multiple signaling pathways,including HIF-1α,PI3K-Akt,FoxO,and mTOR,in B.calyciflorus,which may underpin the organism's responses to polystyrene NP exposure.These findings contribute to the advancement of predictive models to assess the ecological risks posed by polystyrene NPs contamination in aquatic ecosystems.展开更多
This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers,which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biologi...This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers,which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biological treatment performance.A common bdelloid rotifer,Habrotrocha sp.,in a wastewater biological treatment system was selected as the culture target.Rotifers fed on flour could reproduce faster than those fed traditional food such as Chlorella vulgaris or mixed bacteria.As a rotifer food,flour has the advantages of simple preparation,effortless preservation,and low cost compared to live Chlorella vulgaris or mixed bacteria,so it is more suitable for the mass culture of rotifers.The optimal rotifer culture conditions using flour as food were also studied.According to the experimental results,the recommended rotifer culture conditions arc a flour particle size of 1 a flour concentration of 6×10^(6) cell/mL,a temperature of 28℃,a pH level of 6.5 and salinity of 100-500 mg/L.In addition,the sludge volume index in the sequencing batch reactor(SBR)with the addition of cultured rotifers was 59.9 mL/g at the end of operation and decreased by 18.2%compared to SBR without rotifer,which indicates that the cultured rotifers still retained the ftinction of helping to improve sludge settling.This function may be related to the rotifer's role in inhibiting bacteria from producing loosely bound extracellular polymeric substances in the SBR.展开更多
We investigated rotifer community structure in the Backshore Wetland of the Expo Garden in Shanghai from September 2009 to August 2010.We identified 116 rotifer species,determined the dominant species and their relati...We investigated rotifer community structure in the Backshore Wetland of the Expo Garden in Shanghai from September 2009 to August 2010.We identified 116 rotifer species,determined the dominant species and their relationships with environmental factors,and community diversity indices.Polyarthra trigla was the most common species over the four seasons and proportionally most dominant in spring and autumn,whereas Cephalodella exigua and Keratella cochlearis were the most dominant species in winter and summer,respectively.There was seasonal variability in species numbers,with the highest numbers in summer,followed by autumn and winter.The mean annual density was 815±1346 ind./L and the biomass was 0.3649±0.4940 mg/L.There were significant differences between months:the highest density(2723±2926 ind./L)and biomass(0.7938±0.8197 mg/L)occurred in June,while the lowest density(238±271 ind./L)and biomass(0.0476±0.0429 mg/L)occurred in May.Canonical correspondence analysis(CCA)indicated that temperature,pH,nitrite nitrogen(NO2-N),and total phosphorus(TP)were the most important abiotic factors affecting rotifer distribution.Our research showed that the adaptability of the rotifers to temperature was the important factor.展开更多
STUDIES on the nutrition requirement of larval fish have made some progress abroad, but therehave been no reports on such studies in China. It was determined recently that n-3 HUFA (es-pecially 22: 6(n-3) (DHA) and 20...STUDIES on the nutrition requirement of larval fish have made some progress abroad, but therehave been no reports on such studies in China. It was determined recently that n-3 HUFA (es-pecially 22: 6(n-3) (DHA) and 20:5 (n-3) (EPA)) is essential for larval seafish growth. Thehigh content of DHA in seafish eggs and the low content of DHA in rotifers show that rotifersas live food cannot satisfy the n-3 HUFA requirement of larval seafish. Some scientists ob-展开更多
Objective:To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species,Brachionus calyciflorus and Lecane quadridentata.Methods:The muscle actin fibers were stained with phalloi...Objective:To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species,Brachionus calyciflorus and Lecane quadridentata.Methods:The muscle actin fibers were stained with phalloidin-linked fluorescent dye,and acetylcholine was detected with Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit,and then confocal scanning laser microscopy was used.Results:The musculature of Brachionus calyciflorus showed a pattern similar to other species of the same genus,while that of Lecane quadridentata was different from other rotifer genera described previously.The cholinergic system was determined by co-localization of both muscles and acetylcholine labels in the whole rotifer,suggesting the presence of neuromuscular junctions.Conclusions:The distribution pattern of muscular and acetylcholine systems showed considerable differences between the two species that might be related to different adaptations to particular ecological niches.The confirmation of a cholinergic system in rotifers contributes to the development of potential neuro-pharmacological and toxicological studies using rotifers as model organism.展开更多
基金Supported by the Scientific Special Fund of Commonweal Industry (Agriculture) of Finance Ministry (No. ayhyzx07-045)the Key Discipline Projects of Shanghai (No. S30701)the Doctor Startup Projects of Shanghai Ocean University
文摘Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894＋ 1 006 indYL and 12.47± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella eochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature （R=0,209, P=0.003; R=0.446, P=0.000）, but the peak density showed two lags in response to chl a. According to the Jaccard similarity index （S0, the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H＇, Margalef richness index D and Pielou evenness index J were 1.96±0.34, 1.61±0.50 and 0.77±0.10, respectively. In all four areas of Yangcheng Lake, β- mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.
基金This work was supported by the National Natural Science Foundation of China under contract Nos 30270258 and 40506028 the National High Technology Research and Development Program of China under contract No. 2002AA648010+2 种基金 the China Postdoctoral Science Foundation under contract No. 2005037237 the Shandong Scientific Research Encouragement Foundation for Talent Youths under contract No. 03BS120the Doctor Scientific Research Foundation of Dongying Vocational College under contract No. B J0602.
文摘Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. , Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively （ P 〈 0.05 ） which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, L galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment （2.70 kJ/m^2）, the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, L galbana and T. chuii in turn. Chlorella sp. , L galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-208)National Natural Science Foundation of China (No. 40821004, U0733006)National Basic Research Program of China (973 Program, No. 2001CB409700)
文摘The toxicity of seven major HAB （harmful algal bloom） species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense （AT-6, non-PSP producer）, Alexandrium lusitanicum, Alexandrum tamarense （ATHK） and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P donghaiense, P. globosa, P. micans, A. tamarense （AT-6）, or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense （ATHK） has strong lethal effect on the rotifer with 48h LCs0 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P micans, A. tamarense （AT-6） and A. lusitanicum can be taken by the rotifers as food, but A. tamarense （ATHK） or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.
基金Supported by the Special Fund for Agro-Scientific Research in the Public Interest(No.20130356)the National Key Technology Research and Development Program of China(No.2012BAD25B08)the National Natural Science Foundation of China(Nos.30830025,31201994)
文摘We evaluated the response of a rotifer community to environmental changes in five shallow lakes in the middle reach of the Changjiang （Yangtze） River in summer and autumn 2010. These five lakes differed in trophic status and rotifer community structure. Twenty-nine rotifer species were collected, of which Keratella cochlearis, Polyarthra dolichoptera, and Trichocerca elongate were dominant. The mean density, Shannon-Wiener diversity, and equitability among the five lakes differed significantly （P〈0.05）. The mean rotifer density was positively correlated with trophic state. The diversity was higher in lakes with high macrophyte coverage. The composition of rotifer species was closely associated with the trophic gradient. Five environmental variables, Secchi depth, conductivity, TN, NHa-N, and TP, significantly affected the composition of rotifer species. Keratella quadrata, Brachionus calyciflorus, and B. forficula were more common in eutrophic conditions. Our results suggest that eutrophication has a significant influence on the rotifer community structure and highlight the potential for using rotifer community structure as an indicator of trophic status in subtropical lakes.
基金Supported by the National Natural Science Foundation of China(Nos.31470445,30970349)
文摘Maternal eff ects are one of the most interesting topics in evolutionary ecology as they can aff ect the rate of evolution and population dynamics by phenotypic manipulation of off spring related to fi tness. At present, studies examining the interaction between maternal environment eff ects and maternal age (birth order) eff ects are scarce. We designed an experiment to reveal whether environmentally induced maternal manipulation works equally on off spring across birth orders in rotifer Brachionus calycifl orus. In the experiment, newborn amictic mothers (F0) were cultured parallelly in low (LD) and high (HD) population density. Off spring (F1) of young (YF0) and old (OF0) mothers in both LD and HD groups were cultured under a crowded condition and the mixis ratios of both F1 and F2 were examined. Results show that F1 from HD-YF0 had a signifi cantly higher mixis ratio and those amictic ones produced daughters (F2 ) with higher mixis ratio in response to crowding than those from HD-OF0. In contrast, no such diff erences among F1 siblings were found in the LD-F0 group. Therefore, the eff ect of maternal age on the sexual propensity of the off spring can be aff ected independently by the maternal population density.
文摘The composition and distribution of benthic, periphytic and planktonic rotifers in different habitatsin Krottensee were investigated. Sixty-five rotifer taxa were identified, their relative abundance estimated. Classification of the data set by cluster analysis allowed the recognition of distinct habitat groupe con-fined to acid bog ponds, macrophytes, sediments, and open water. Five groups of rotifer taxa were identifiedon the basis of their habitat preferences and the occurrence of the taxa. Highest diversities were found onmacrophytes and in acid bog ponds.
基金This work has been done under the Socrates-Erasmus Student Mobility Programme （in Gent University and Royal Belgian Institute of Natural Sciences）. ACKN0WLEDGEMENTS Thank Dr. Hendrik Segers for helping identifying some rotifer species and giving opportunity to study at the Royal Belgian Institute of Natural Sciences in Brussels, Belgium. Also thank Prof. Dr. Henri J. Dumont （Gent University, Belgium） for collecting some of the samples.
文摘Thirteen rotifer species belonging to the families Lepadellidae and Trichocercidae were studied taxonomically from nine water bodies in Turkey. Lepadella biloba is a new entry to the Turkish rotifer fauna. All species were drawn under a light microscope using a camera lucida.
文摘Of more than 90 rotifer taxa found in Denghu Lake and its nearby ponds in Wuhan, Hubei,the following were new to science: Brachionus angularis pyriformis, B. a. donghuensis, B. (Schizocerca) brevispina, Anuraeopsis fissa donghuensis, A. f. pseudonavicula, Mytilina ventralis Wuhanensis and Trichocerca similis strumosa.
基金Supported by Alexandria University Research Fund,Egupt(Gran 9522-2010)
文摘Objective:To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes.Methods:Susceptible laboratory-bred Biomphalaria alexandrina(B.alexandrina)snails were exposed to lab-maintained rotifers;Philodinaspp.,two weeks before and after being infected with Schistosoma mansoni(S.mansoni)miracidia.The consequent histopathological impact on snail tissues and cercarial biology were investigated before and after emergence from snails.Results:Contamination of B.alexandrinasnails with philodina,two weeks before miracidial exposure,was found to hinder the preliminary development of S.mansonicercariae inside the snail tissues.Furthermore,when snails were contaminated with rotifers two weeks post miracidial exposure;growth of already established cercariae was found to be retarded.The consequent influence of internalized rotifers within the snail tissue was clearly reflected on cercarial em ergence,activity and infectivity along the four weeks duration of shedding.In the present study,comparison of snail histopathological findings and altered cercarial biology observed between the experimental and control groups indicated that the rotifers may have affected the levels of snail's energy reservoirs,which eventually was found to have had an adverse impacton reproduction,growth and survival of the parasite within the snail host,coupled with its performance outside the snail.Conclusions:In future biological control strategies of schistosomiasis,ritifers should be considered as a parasitic scourge of humanity.
基金The National Natural Science Foundation of China under contract Nos 30270258 and 40506028the National High Technology Research and Development Program of China under contract No. 2002AA648010+2 种基金the China Postdoctoral Science Foundation under contract No. 2005037237the Shandong Scientific Research Encouragement Foundation for Talent Youths under contract No. 03BS120the Doctor Scientific Research Foundation of Dongying Vocational College under contract Nos BJ0602 and KJ0804
文摘The effect of UV-B radiation enhancement at experimental doses of 0.00,0.24,0.48,0.72,0.96,and 1.20 kJ/m 2 on the population dynamics of the rotifer Brachionus urceus feeding on the alga Chlorella sp.was studied under controlled laboratory conditions using clonal culture and life-table techniques.The results show that UV-B radiation treatment significantly shortened the survival time of the rotifer （P 0.05）： The longest survival time （336 h） occurred in the control （0.00 kJ/m 2 ） while the shortest （222 h） occurred when exposed to the highest UV-B radiation treatment （1.20 kJ/m 2 ）.The fecundity of the rotifer B.urceus was enhanced by the lower UV-B radiation treatment （0.24 and 0.48 kJ/m 2 ） but inhibited by the higher treatments （0.96 and 1.20 kJ/m 2 ）.Life expectancy also was obviously affected by UV-B radiation （P 0.05）.The highest life expectancy occurred in the control （0.00 kJ/m 2 ）,and it became shorter with increasing doses of UV-B radiation.The resutls in the present study indicate that the life expectancy of the rotifer B.urceus can be used as an indicator for UV-B radiation enhancement.
基金Supported by the National Natural Science Foundation of China(Nos.31601840,41673080)。
文摘A new freshwater rotifer Cephalodella changdensis sp.nov.discovered in two locations in Changde,Hunan,China,is described morphologically.The new species is characterized by body shape moderately elongate,double eyespots frontally,toes conical and almost straight,about one fourth of total length,trophi type B(classification after Wulfert,1937),rami asymmetrical with a pair of long alulae,fulcrum inverted T-shaped(ventral/dorsal view)with dorsally directed distal projection(lateral view),and manubria asymmetrical,left one slightly longer and stronger,with J-shaped or crutch-shaped posterior ends.
文摘Planktonic rotifers were examined from April to October 2007 in two ponds created by sand extraction: Hubertus III (infrequently used for recreation)—pond I and Stawiki (commonly used for recreation)—pond II. The ponds are located within the protected Landscape Complex “Szopienice-Borki” in Silesian Upland (SW Poland). A total number of 58 taxa of rotifers were noted. The number of rotifer species and their densities were smaller in pond I than in pond II. In pond I, Polyarthra species were the most abundant, accounting for 48% of total rotifer density, whereas in pond II, Keratella cochlearis reached the highest density (accounting for 36% of total density). Analysis of variance (ANOVA) revealed a significant difference between communities of rotifers in species diversity (F = 5.88, p = 0.02) and species richness (F = 5.57, p = 0.03). The research proved that the pond commonly used for recreation (pond II) is characterized by a higher trophic state. Results of this study indicate that the methods and range of use of water bodies by humans have an important influence on the species richness and diversity of communities of planktonic rotifers.
文摘Rotifers are considered as one of the most important prey organisms in the culture of altricial fish larvae. However, high density rotifer culture is often problematic due to water quality problems which results in frequent crashes. In the present study, the performance of a small-scale, continuous system was evaluated for culturing rotifers, Brachionus plicatilis, using concentrated nonviable green algae, Nannochloropsis oculeataas feed in a 160 L tank for a period of 90 days. The system configuration was simple and major components consisted of a protein skimmer and a pure oxygen delivery system. Although egg ratio increased from 3% on day 1 to 21.8% and 39.3% on days 7 and 9, respectively, rotifer growth was slow at start up and resulted in fluctuations in total number of rotifers between days 19-41. Rotifer densities remained 〈 400 until day 51 but increased at higher rates reaching 900 individuals/mL on day 55, 1,620 on day 60 and 2,127 on day 70. Rotifer density reached a maximum of 2,188 individuals/mL on day 85. Once the rotifer density exceeded 1,500 individuals/mL （day 60）, periodical harvesting （a total of 16 harvest events） produced a total of 369,920,000 rotifers corresponding to a daily production of 12,330,667 individuals/day during the next 30 days until the experiment was terminated at day 90. As a result of periodic harvesting, water makeup and continuous protein skimming, total settleable solids and NH3-N levels remained low and ranged between 4-22 mL/L and 0.4-2.2 mg/L, respectively. The authors＇ findings indicated that this inexpensive culture system can be successfully used for small-scale marine or freshwater ornamental fish production. Further work is required to minimize lag period at start-up and increase the production potential and yield by better management of suspended solids.
文摘The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and manage this ecosystem is vital. The aim of this work is to study the physicochemical parameters of the environment that influence the diversity and spatiotemporal distribution of Cladocerans and Rotifers in the mangrove waters of Mouanko. This study was carried out from November 2019 to October 2020 at 8 sampling stations. Both biological and physico-chemical sampling and analyses were done following standard recommendations. The results of the phyico-chemical analyses revealed that the waters of the Mouanko mangroves were slightly basic (7.64 ± 0.71 UC), moderately oxygenated (69.56% ± 14.29%) with low levels of nutrients [ NO <sup>-</sup>2</sub> (0. 06 ± 0.05 mg/L), NH<sup>+</sup>4</sub> (0.39 ± 0.3 mg/L) and PO<sup>3-</sup>4</sub> (up to 0.12 mg/L)] and high values of electrical conductivity (up to 6531.04 μS/cm), salinity (up to 3.71‰). 15 species of Cladocerans and 30 species of Rotifers were identified accounting for a total abundance of 612 ind/L. The species richness was higher in freshwater influenced zones (40 taxa) compared to marinewater influenced zones (17 taxa). Among these species, the Cladocera, Penilia avirostris was the most abundant in marinewater influenced zones (84 ind/L) while the Rotifer, Keratella tecta was the most abundant in freshwater influenced zones (64 ind/L). Shannon-Weaver’s diversity and Pielou’s equitability indices indicated that freshwater influenced zones host a diverse community with a tendency towards equi-partition of species while marinewater influenced zones revealed the opposite. The low levels of organic pollution indicator variables recorded and the high diversity of the freshwater influenced zones population studied attested to the low level of anthropization in this environment. High salinity and electrical conductivity values influence the distribution of these organisms.
基金Supported by the earmarked fund for China Agriculture Research System(No.CARS-50)the Doctors Research Funding of Henan Normal University(No.20230246)。
文摘Nanoplastics(less than 1µm in size,NPs)have emerged as a significant pollutant in aquatic environment,posing considerable threats to freshwater biota.However,the mechanisms through which NPs modulate the predation responses of these organisms remain poorly elucidated.We investigated the impacts of polystyrene NPs,characterized by a representative particle size(diameter:50 nm;concentration:0–8μg/L),on the anti-predation defense mechanisms of mature rotifer Brachionus calyciflorus against predator of rotifer Asplanchna brightwellii,utilizing transcriptomics to unravel the underlying molecular pathways.Results reveal that the posterolateral spine length and type of B.calyciflorus serve as robust indicators of defensive morphology,even in the presence of NPs exposure.Specifically,increasing concentrations of NPs and predator cues suppressed the defensive responses,which was associated with morphological transformations.This suppression was associated with the down-regulation of the HIF-1αsignaling pathway,implicating potentially its role in modulating fight-or-flight responses.Furthermore,we identified functional crosstalk among multiple signaling pathways,including HIF-1α,PI3K-Akt,FoxO,and mTOR,in B.calyciflorus,which may underpin the organism's responses to polystyrene NP exposure.These findings contribute to the advancement of predictive models to assess the ecological risks posed by polystyrene NPs contamination in aquatic ecosystems.
基金This research was financially supported by the National Natural Science Foundation of China(Grant No.21777092).
文摘This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers,which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biological treatment performance.A common bdelloid rotifer,Habrotrocha sp.,in a wastewater biological treatment system was selected as the culture target.Rotifers fed on flour could reproduce faster than those fed traditional food such as Chlorella vulgaris or mixed bacteria.As a rotifer food,flour has the advantages of simple preparation,effortless preservation,and low cost compared to live Chlorella vulgaris or mixed bacteria,so it is more suitable for the mass culture of rotifers.The optimal rotifer culture conditions using flour as food were also studied.According to the experimental results,the recommended rotifer culture conditions arc a flour particle size of 1 a flour concentration of 6×10^(6) cell/mL,a temperature of 28℃,a pH level of 6.5 and salinity of 100-500 mg/L.In addition,the sludge volume index in the sequencing batch reactor(SBR)with the addition of cultured rotifers was 59.9 mL/g at the end of operation and decreased by 18.2%compared to SBR without rotifer,which indicates that the cultured rotifers still retained the ftinction of helping to improve sludge settling.This function may be related to the rotifer's role in inhibiting bacteria from producing loosely bound extracellular polymeric substances in the SBR.
基金Project of Shanghai Municipal Committee of Fisheries Animal Genetics and Breeding Center of Shanghai Collaborative Innovation Center(ZF1206)National Science and Technology Commission of Scientific and Technological Research of Expo special(2005ba908b23)Shanghai Science and Technology Commission Expo special(05dz05823)。
文摘We investigated rotifer community structure in the Backshore Wetland of the Expo Garden in Shanghai from September 2009 to August 2010.We identified 116 rotifer species,determined the dominant species and their relationships with environmental factors,and community diversity indices.Polyarthra trigla was the most common species over the four seasons and proportionally most dominant in spring and autumn,whereas Cephalodella exigua and Keratella cochlearis were the most dominant species in winter and summer,respectively.There was seasonal variability in species numbers,with the highest numbers in summer,followed by autumn and winter.The mean annual density was 815±1346 ind./L and the biomass was 0.3649±0.4940 mg/L.There were significant differences between months:the highest density(2723±2926 ind./L)and biomass(0.7938±0.8197 mg/L)occurred in June,while the lowest density(238±271 ind./L)and biomass(0.0476±0.0429 mg/L)occurred in May.Canonical correspondence analysis(CCA)indicated that temperature,pH,nitrite nitrogen(NO2-N),and total phosphorus(TP)were the most important abiotic factors affecting rotifer distribution.Our research showed that the adaptability of the rotifers to temperature was the important factor.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39470562).
文摘STUDIES on the nutrition requirement of larval fish have made some progress abroad, but therehave been no reports on such studies in China. It was determined recently that n-3 HUFA (es-pecially 22: 6(n-3) (DHA) and 20:5 (n-3) (EPA)) is essential for larval seafish growth. Thehigh content of DHA in seafish eggs and the low content of DHA in rotifers show that rotifersas live food cannot satisfy the n-3 HUFA requirement of larval seafish. Some scientists ob-
基金Supported by Consejo Nacional de Ciencia y Tecnología(Conacyt)through the scholarship(Grant No.136453)Sistema Nacional de Investigadores(Grant No.49351).
文摘Objective:To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species,Brachionus calyciflorus and Lecane quadridentata.Methods:The muscle actin fibers were stained with phalloidin-linked fluorescent dye,and acetylcholine was detected with Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit,and then confocal scanning laser microscopy was used.Results:The musculature of Brachionus calyciflorus showed a pattern similar to other species of the same genus,while that of Lecane quadridentata was different from other rotifer genera described previously.The cholinergic system was determined by co-localization of both muscles and acetylcholine labels in the whole rotifer,suggesting the presence of neuromuscular junctions.Conclusions:The distribution pattern of muscular and acetylcholine systems showed considerable differences between the two species that might be related to different adaptations to particular ecological niches.The confirmation of a cholinergic system in rotifers contributes to the development of potential neuro-pharmacological and toxicological studies using rotifers as model organism.
