The inland saltwater lakes harbor exceptional biodiversity.Here,two new species of solitary sessile peritrich ciliates were isolated from Qinghai Lake,the largest inland saltwater lake in China.Their morphology,ciliat...The inland saltwater lakes harbor exceptional biodiversity.Here,two new species of solitary sessile peritrich ciliates were isolated from Qinghai Lake,the largest inland saltwater lake in China.Their morphology,ciliature,silverline system,and molecular phylogeny were investigated based on live observation,silver staining,and analysis of the small subunit ribosomal DNA(SSU rDNA).Vorticella paraglobosa sp.n.is characterized mainly by its obconical or elongate bell-shaped zooid,C-shaped macronucleus,single ventrally located contractile vacuole,two-rowed infundibular polykinety 3,and 28-38 silverlines between peristome and aboral tro-chal band and 10-15 between aboral trochal band and scopula.Vorticella cotyliformis sp.n.differs from its congeners mainly by its double-layered peristomial lip,cup-shaped zooid,J-shaped macronucleus,single ventrally positioned contractile vacuole,three-rowed infundibular polykinety 3,and 70-85 silverlines between peristome and aboral trochal band and 21-25 between aboral trochal band and scopula.The SSU rDNA sequences of the two new species were obtained,and the subsequent molecular phylogenetic analysis supported their taxonomic classification.展开更多
Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers ...Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers were selected to amplify the DNA polymorphy.The genetic distances inferred from the pairwise similarities were calculated for the phylogenetic tree construction.Meantime,the traditional microscopic determination,a way of visualizing the species composition,was performed to detect the major taxa of microplanktons from all samples.Results showed that：（1） the band sharing index values were in the range of 0.504 2-0.763 2 among samples from the same sampling site at different time scales,while 0.406 5-0.685 7 among the samples from different stations at the same time scales,indicating that spatial variations of microplankton communities were more pronounced than temporal ones;（2） samples from the same station basically clustered together,corresponding to the geographic distribution of the sampling sites;（3） diversity derived from genetic and morphological data did not correspond with each other well.展开更多
Ecotoxic effects of antibiotics or ammonium have been confirmed independently in aquatic animals,but few studies have investigated their combined effects.In aquaculture ecosystems,these pollutants frequently coexist,a...Ecotoxic effects of antibiotics or ammonium have been confirmed independently in aquatic animals,but few studies have investigated their combined effects.In aquaculture ecosystems,these pollutants frequently coexist,and often in high concentrations.In this study,the combined effects of antibiotic nitrofurazone and NH4 Cl on the population dynamics and growth rates of two species of ciliated protists,Euplotes vannus and Pseudokeronopsis rubra,were investigated.Profiles of the dose-responses were visualized,and interactions between the two pollutants were quantified by the response surface method(RSM).Results showed that 1)the dynamics of the population growth differed significantly between the testd ciliates and varied with the concentrations of the pollutants;2)the relative growth rate(RGR)of both ciliates decreased significantly with increased pollutant concentrations,while the difference in RGR between the two ciliates was not significant;3)RSM analysis demonstrated an additive effect of nitrofurazone and NH4 Cl on the RGR in both ciliates.In brief,ecotoxic effects can be caused by nitrofurazone and ammonium independently on the two test ciliates,and such effects can be strengthened when they present at the same time.These findings offer a valuable reference for evaluating combined ecotoxic effects caused by multiple pollutants in aquaculture ecosystems.展开更多
It is a practical approach to select candidate probiotic bacterial stains on the basis of their special traits. Production of digestive enzyme was used as a trait to select a candidate probiotic bacterial strain in th...It is a practical approach to select candidate probiotic bacterial stains on the basis of their special traits. Production of digestive enzyme was used as a trait to select a candidate probiotic bacterial strain in this study. In order to select a bacterium with the ability to degrade both starch and protein, an ideal bacterial strain STE was isolated from marine shrimp (Litopenaeus vannamei) intestines by using multiple selective media.The selected isolate STE was identified on the basis of its morphological, physiological,and biochemical characteristics as well as molecular analyses. Results of degradation experiments confirmed the ability of the selected isolate to degrade both starch and casein. The isolate STE was aerobic, Gram-negative, rod-shaped, motile and non-spore-forming, and had catalase and oxidase activities but no glucose fermentation activity. Among the tested carbon/nitrogen sources, only Tween40, alanyl-glycine, aspartyl-glycine, and glycyl-l-glutamic acid were utilized by the isolate STE. Results of homology comparison analyses of the 16S rDNA sequences showed that the isolate STE had a high similarity to several Pseudoalteromonas species and, in the phylogenetic tree, grouped with P. ruthenica with maximum bootstrap support (100%). In conclusion, the isolate STE was characterized as a novel strain belonging to the genus Pseudoalteromonas.This study provides a further example of a probiotic bacterial strain with specific characteristics isolated from the host gastrointestinal tract.展开更多
基金supported by the projects of the National Natural Science Foundation of China(Nos.42076113,42176145)the Fundamental Research Funds for the Central Universities(Nos.20720200106,20720200109).
文摘The inland saltwater lakes harbor exceptional biodiversity.Here,two new species of solitary sessile peritrich ciliates were isolated from Qinghai Lake,the largest inland saltwater lake in China.Their morphology,ciliature,silverline system,and molecular phylogeny were investigated based on live observation,silver staining,and analysis of the small subunit ribosomal DNA(SSU rDNA).Vorticella paraglobosa sp.n.is characterized mainly by its obconical or elongate bell-shaped zooid,C-shaped macronucleus,single ventrally located contractile vacuole,two-rowed infundibular polykinety 3,and 28-38 silverlines between peristome and aboral tro-chal band and 10-15 between aboral trochal band and scopula.Vorticella cotyliformis sp.n.differs from its congeners mainly by its double-layered peristomial lip,cup-shaped zooid,J-shaped macronucleus,single ventrally positioned contractile vacuole,three-rowed infundibular polykinety 3,and 70-85 silverlines between peristome and aboral trochal band and 21-25 between aboral trochal band and scopula.The SSU rDNA sequences of the two new species were obtained,and the subsequent molecular phylogenetic analysis supported their taxonomic classification.
基金The National Natural Science Foundation of China under contract Nos 30570236,U0633006,40506033 and 40676076the Program for New Century Excellent Talents in Universities of China under contract No. NCET05-0595
文摘Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers were selected to amplify the DNA polymorphy.The genetic distances inferred from the pairwise similarities were calculated for the phylogenetic tree construction.Meantime,the traditional microscopic determination,a way of visualizing the species composition,was performed to detect the major taxa of microplanktons from all samples.Results showed that：（1） the band sharing index values were in the range of 0.504 2-0.763 2 among samples from the same sampling site at different time scales,while 0.406 5-0.685 7 among the samples from different stations at the same time scales,indicating that spatial variations of microplankton communities were more pronounced than temporal ones;（2） samples from the same station basically clustered together,corresponding to the geographic distribution of the sampling sites;（3） diversity derived from genetic and morphological data did not correspond with each other well.
基金supported by the National Natural Science Foundation of China(Nos.31971519,31430077,41476128)in part by a grant from the Dedicated Fund for Promoting High-Quality Economic Development in Guangdong Province(Marine Economic Development Project:GDOE(2019)A23)。
文摘Ecotoxic effects of antibiotics or ammonium have been confirmed independently in aquatic animals,but few studies have investigated their combined effects.In aquaculture ecosystems,these pollutants frequently coexist,and often in high concentrations.In this study,the combined effects of antibiotic nitrofurazone and NH4 Cl on the population dynamics and growth rates of two species of ciliated protists,Euplotes vannus and Pseudokeronopsis rubra,were investigated.Profiles of the dose-responses were visualized,and interactions between the two pollutants were quantified by the response surface method(RSM).Results showed that 1)the dynamics of the population growth differed significantly between the testd ciliates and varied with the concentrations of the pollutants;2)the relative growth rate(RGR)of both ciliates decreased significantly with increased pollutant concentrations,while the difference in RGR between the two ciliates was not significant;3)RSM analysis demonstrated an additive effect of nitrofurazone and NH4 Cl on the RGR in both ciliates.In brief,ecotoxic effects can be caused by nitrofurazone and ammonium independently on the two test ciliates,and such effects can be strengthened when they present at the same time.These findings offer a valuable reference for evaluating combined ecotoxic effects caused by multiple pollutants in aquaculture ecosystems.
基金financially supported by the National High Technology Research and Development Project of China(863 Project,No.2001AA622060 and No.2003A-A622060)
文摘It is a practical approach to select candidate probiotic bacterial stains on the basis of their special traits. Production of digestive enzyme was used as a trait to select a candidate probiotic bacterial strain in this study. In order to select a bacterium with the ability to degrade both starch and protein, an ideal bacterial strain STE was isolated from marine shrimp (Litopenaeus vannamei) intestines by using multiple selective media.The selected isolate STE was identified on the basis of its morphological, physiological,and biochemical characteristics as well as molecular analyses. Results of degradation experiments confirmed the ability of the selected isolate to degrade both starch and casein. The isolate STE was aerobic, Gram-negative, rod-shaped, motile and non-spore-forming, and had catalase and oxidase activities but no glucose fermentation activity. Among the tested carbon/nitrogen sources, only Tween40, alanyl-glycine, aspartyl-glycine, and glycyl-l-glutamic acid were utilized by the isolate STE. Results of homology comparison analyses of the 16S rDNA sequences showed that the isolate STE had a high similarity to several Pseudoalteromonas species and, in the phylogenetic tree, grouped with P. ruthenica with maximum bootstrap support (100%). In conclusion, the isolate STE was characterized as a novel strain belonging to the genus Pseudoalteromonas.This study provides a further example of a probiotic bacterial strain with specific characteristics isolated from the host gastrointestinal tract.
