To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the dow...To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.展开更多
Bronchiectasis is a chronic lung disorder and a number of bacterial pathogens are involved.However,30%-40% of sputum and purulent samples in good quality failed to grow any pathogenic bacteria,making it difficult to c...Bronchiectasis is a chronic lung disorder and a number of bacterial pathogens are involved.However,30%-40% of sputum and purulent samples in good quality failed to grow any pathogenic bacteria,making it difficult to confirm the pathogen.In this study,we collected bronchoalveolar lavage fluid from a bronchiectasis patient undergoing acute exacerbation,and sent for 16 S rDNA pyrosequencing by a 454 GS Junior machine.Metagenomic analysis showed the composition of bacterial community in sample was complex.More than a half of reads（51.3%） were from Pseudomonas aeruginosa.This result was corresponding with the culture result but came out 2 d earlier,which is meaningful for early diagnosis and treatment.The detection with 16 S rDNA pyrosequencing technology is more sensitive and rapid than routine culture,and can detect the co-infection or symbiosis in airway,giving us a novel and convenient approach to perform rapid diagnosis.展开更多
Some ion-associated species existed possibly in NaNO3 solution were investigated via the ab-initio method. The hydrated ion parings, triple and multiple ion clusters in NaNO3 solution are all analogous to those in Mg...Some ion-associated species existed possibly in NaNO3 solution were investigated via the ab-initio method. The hydrated ion parings, triple and multiple ion clusters in NaNO3 solution are all analogous to those in Mg（NO3）2 system except that the bi-dentate structures can not be formed. Only one solvent-shared ion paring has larger v1-NO3^- frequency than the hydrated NO3^- ion. And all triple clusters with two hydrated Na^＋ ions and one NO3^- have larger v1-NO3^- frequency than the hydrated NO3^- ion. The ion association process in NaNO3 solution is predicted as free ions→solvent-separated ion pairings→solvent-shared ion pairings→solvent-shared triple ion clusters→contact triple ion clusters→contact multiple ion clusters→amorphous NaNO3, which is not analogous to that in MgSO4 but those in Mg（NO3）2 and Mg（ClO4）2 systems.展开更多
The associations of each of midecamycin and chloroquine phosphate to hydrogen peroxide were studied by using linear-potential scan polarography. In a 0.15 mol/L KH 2PO 4-NaOH(pH 7.4) buffer, the association ratio of...The associations of each of midecamycin and chloroquine phosphate to hydrogen peroxide were studied by using linear-potential scan polarography. In a 0.15 mol/L KH 2PO 4-NaOH(pH 7.4) buffer, the association ratio of the association complex of midecamycin to hydrogen peroxide is 1∶1, and the apparent association constant is 7.18. While in a 0.04 mol/L NH 3·H 2O-NH 4Cl(pH 9.5) buffer, the association ratio and the apparent association constant of the association complex of chloroquine phosphate to hydrogen peroxide are 1∶1 and 45.4, respectively. The formation of the association complexes stabilizes H 2O 2 and results in the accumulation of H 2O 2, which is baneful to human body.展开更多
Based on our field investigation,we analyzed the characteristics of species diversity and interspecific association at different development stages of Hippohae rhamnoides plantations.The results show that the species ...Based on our field investigation,we analyzed the characteristics of species diversity and interspecific association at different development stages of Hippohae rhamnoides plantations.The results show that the species diversities of the shrub layer,grass layer and the whole community of the H.rhamnoides plantations all fluctuated in an“S”shape pattern.At different development stages,the species richness and diversity were higher in the grass layer than in the shrub layer.The shrub species diversity was lower on bare land,but increased gradually with development of the community.The shrub evenness index was higher in 13-year forest stand,while the grass diversity index was higher in the 3-year and 25-year plantations and lower in the 8-year plantation.The positive and negative absolute values of interspecific association between H.rhamonides and other principal species changed in a parabolic pattern.The significance level and intensity of interspecific association were lower or weaker in the13-year plantation,indicating that the species substitution rate slowed down,competition became less intense and community composition and its structure reached a relatively stable state.Therefore,to improve the ecological environment,priority should be given to the protection of the H.rhamnoides plantations younger than 13 years,while for those of 25 year plantations,moderate thinning should be made to promote their regeneration.展开更多
基金Supported by the National Key Scientific Research Project(No.2018YFC1508200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX 23_0714)+1 种基金the China Scholarship Council(No.202206710066)the Construction Project of Wenzhou Hydrology High quality Development Pilot Zone(No.WZSW-GZLFZXXQ-202105)。
文摘To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.
基金supported by grants from the Ministry of Science and Technology of China(National High-Tech R&D program:No.2006AA02Z4A9 and No.2012BAI05B0212th Five-Year Plan Major Scientific and Technological Program:No.2012ZX10004-206)the Ministry of Health of China(Special Fund for Health-scientific Research in the Public Interest Program:No.201202011)
文摘Bronchiectasis is a chronic lung disorder and a number of bacterial pathogens are involved.However,30%-40% of sputum and purulent samples in good quality failed to grow any pathogenic bacteria,making it difficult to confirm the pathogen.In this study,we collected bronchoalveolar lavage fluid from a bronchiectasis patient undergoing acute exacerbation,and sent for 16 S rDNA pyrosequencing by a 454 GS Junior machine.Metagenomic analysis showed the composition of bacterial community in sample was complex.More than a half of reads（51.3%） were from Pseudomonas aeruginosa.This result was corresponding with the culture result but came out 2 d earlier,which is meaningful for early diagnosis and treatment.The detection with 16 S rDNA pyrosequencing technology is more sensitive and rapid than routine culture,and can detect the co-infection or symbiosis in airway,giving us a novel and convenient approach to perform rapid diagnosis.
基金Supported by the National Natural Science Foundation of China(No.20772048)
文摘Some ion-associated species existed possibly in NaNO3 solution were investigated via the ab-initio method. The hydrated ion parings, triple and multiple ion clusters in NaNO3 solution are all analogous to those in Mg（NO3）2 system except that the bi-dentate structures can not be formed. Only one solvent-shared ion paring has larger v1-NO3^- frequency than the hydrated NO3^- ion. And all triple clusters with two hydrated Na^＋ ions and one NO3^- have larger v1-NO3^- frequency than the hydrated NO3^- ion. The ion association process in NaNO3 solution is predicted as free ions→solvent-separated ion pairings→solvent-shared ion pairings→solvent-shared triple ion clusters→contact triple ion clusters→contact multiple ion clusters→amorphous NaNO3, which is not analogous to that in MgSO4 but those in Mg（NO3）2 and Mg（ClO4）2 systems.
基金Supported by the National Natural Science Foundation of P.R.China(No.2 0 4 75 0 4 3) and the Natural Science Foun-dation of Shaanxi Province(No.2 0 0 2 B0 1)
文摘The associations of each of midecamycin and chloroquine phosphate to hydrogen peroxide were studied by using linear-potential scan polarography. In a 0.15 mol/L KH 2PO 4-NaOH(pH 7.4) buffer, the association ratio of the association complex of midecamycin to hydrogen peroxide is 1∶1, and the apparent association constant is 7.18. While in a 0.04 mol/L NH 3·H 2O-NH 4Cl(pH 9.5) buffer, the association ratio and the apparent association constant of the association complex of chloroquine phosphate to hydrogen peroxide are 1∶1 and 45.4, respectively. The formation of the association complexes stabilizes H 2O 2 and results in the accumulation of H 2O 2, which is baneful to human body.
基金The work was supported by the Experimental and Demonstration Study of Soil Conservation and Sustainable Ecosystem Rehabilitation on the Loess Plateau(No.KZCX2-XB2-05)Vegetation Configuration Optimized and Sustained Management Construction Technology in Loess Plateau+1 种基金the fund of the Key Laboratory Soil Erosion and Dry-land Agriculture in the Loess Plateau(No.10501.159)the fund of Shangrao Normal College Scientific Research(No.0610).
文摘Based on our field investigation,we analyzed the characteristics of species diversity and interspecific association at different development stages of Hippohae rhamnoides plantations.The results show that the species diversities of the shrub layer,grass layer and the whole community of the H.rhamnoides plantations all fluctuated in an“S”shape pattern.At different development stages,the species richness and diversity were higher in the grass layer than in the shrub layer.The shrub species diversity was lower on bare land,but increased gradually with development of the community.The shrub evenness index was higher in 13-year forest stand,while the grass diversity index was higher in the 3-year and 25-year plantations and lower in the 8-year plantation.The positive and negative absolute values of interspecific association between H.rhamonides and other principal species changed in a parabolic pattern.The significance level and intensity of interspecific association were lower or weaker in the13-year plantation,indicating that the species substitution rate slowed down,competition became less intense and community composition and its structure reached a relatively stable state.Therefore,to improve the ecological environment,priority should be given to the protection of the H.rhamnoides plantations younger than 13 years,while for those of 25 year plantations,moderate thinning should be made to promote their regeneration.
