The settlement substrates of nona-porous abalones （Haliotis diversicolor supertexta） are covered with biofilms in which several types of microorganisms coexist and interact. These microorganisms are usually importan...The settlement substrates of nona-porous abalones （Haliotis diversicolor supertexta） are covered with biofilms in which several types of microorganisms coexist and interact. These microorganisms are usually important causes of juvenile abalone disease as well as organisms useful in promoting abalones’ adhesion. The bacterial community structure of the biofilms remains unclear. The aim of this research was to determine the genetic diversity and phylogenetic affiliation of the biofilm bacteria. Total DNA of bacteria in biofilms was extracted, and 16S rRNA gene clone library was constructed using the primers specific for the domain bacteria. Subsequently, 30 randomly selected positive clones were screened by PCR-restriction fragment length polymorphism （PCR-RFLP） analysis, and resulted in 15 different RFLP patterns. Sequences analysis of representatives from each unique RFLP type revealed high genetic diversity in the bacterial populations. These sequences fell into nine major lineages of the bacterial domains： α-, β-, γ-and δ-subdivisions of the Proteobacteria; Planctomycete, Actinobacteria, Firmicutes, V errucomicrobium spp., and CytophagaFlexibacter-Bacteroides spp. Phylogenetic analysis indicated that the dominant phylotypes were most closely related to environmental and clinical Burkholderia cepacia of the β-Proteobacteria, and Roseobacteria of the α-Proteobacteria.展开更多
The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the pro...The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the proliferation of the benthic stage(polyps). Previous experiments have mainly focused on the substrate choices of Aurelia spp. planulae. However, substrate preferences for the proliferation and immigration of polyps have not been reported. We monitored the propagation and immigration of Aurelia aurita(s. l.) polyps on two natural and nine artificial substrates at constant temperature(20±0.5°C) and salinity(30±0.5) in beakers and a glass aquarium in the laboratory, respectively. The results showed that, among artificial substrates, the highest number for polyp proliferation and immigration was found on nets, rigid polyvinyl chloride plates(RPVC), and wood. The lowest density of polyps was present on iron plates. Among natural substrates, the asexual reproduction rate of polyps on Patinopecten yessoensis(Jay, 1857) shells was significantly higher than Azumapecten farreri(Jones & Preston, 1904). On the account of the distinction in the roughness, chemical properties and biofilms of these material surfaces, bare artificial or natural substrates discriminatively affect the proliferation and the immigration of Aurelia spp. polyps at laboratory. These observations suggest that, even in the natural environment, different materials and texture may influence the composition and the abundance of the fouling communities and the assemblages of polyps and, indirectly, have effects on the amounts of released medusae.展开更多
Based on field survey and research of Hanzhong, relocation of Nanzheng County was explored and the existing problems were analyzed. Furthermore, the re- gional characters of Nanzheng County were investigated to analyz...Based on field survey and research of Hanzhong, relocation of Nanzheng County was explored and the existing problems were analyzed. Furthermore, the re- gional characters of Nanzheng County were investigated to analyze the feasibility and necessity of relocation with lots of data and evaluation was made on relocation of Nanzheng County. In addition, the existing problems of relocation were concluded and the prospect of the county was discussed, which is of significance for relocation in Nanzheng County and even southern Shaanxi Province.展开更多
基金The Natural Science Foundation of Fujian Province of China under contract Nos 2005k055 and B0740012the Innovative Research Team under contract No 2006A001Science Foundation of Jimei University, China
文摘The settlement substrates of nona-porous abalones （Haliotis diversicolor supertexta） are covered with biofilms in which several types of microorganisms coexist and interact. These microorganisms are usually important causes of juvenile abalone disease as well as organisms useful in promoting abalones’ adhesion. The bacterial community structure of the biofilms remains unclear. The aim of this research was to determine the genetic diversity and phylogenetic affiliation of the biofilm bacteria. Total DNA of bacteria in biofilms was extracted, and 16S rRNA gene clone library was constructed using the primers specific for the domain bacteria. Subsequently, 30 randomly selected positive clones were screened by PCR-restriction fragment length polymorphism （PCR-RFLP） analysis, and resulted in 15 different RFLP patterns. Sequences analysis of representatives from each unique RFLP type revealed high genetic diversity in the bacterial populations. These sequences fell into nine major lineages of the bacterial domains： α-, β-, γ-and δ-subdivisions of the Proteobacteria; Planctomycete, Actinobacteria, Firmicutes, V errucomicrobium spp., and CytophagaFlexibacter-Bacteroides spp. Phylogenetic analysis indicated that the dominant phylotypes were most closely related to environmental and clinical Burkholderia cepacia of the β-Proteobacteria, and Roseobacteria of the α-Proteobacteria.
基金Supported by the State Key Program of National Natural Science of China(No.41230963)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA11020305)+1 种基金the Shandong Joint Fund for Marine Ecology and Environmental Sciences(No.U1406403)the National Natural Science Foundation of China(No.41506144)
文摘The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the proliferation of the benthic stage(polyps). Previous experiments have mainly focused on the substrate choices of Aurelia spp. planulae. However, substrate preferences for the proliferation and immigration of polyps have not been reported. We monitored the propagation and immigration of Aurelia aurita(s. l.) polyps on two natural and nine artificial substrates at constant temperature(20±0.5°C) and salinity(30±0.5) in beakers and a glass aquarium in the laboratory, respectively. The results showed that, among artificial substrates, the highest number for polyp proliferation and immigration was found on nets, rigid polyvinyl chloride plates(RPVC), and wood. The lowest density of polyps was present on iron plates. Among natural substrates, the asexual reproduction rate of polyps on Patinopecten yessoensis(Jay, 1857) shells was significantly higher than Azumapecten farreri(Jones & Preston, 1904). On the account of the distinction in the roughness, chemical properties and biofilms of these material surfaces, bare artificial or natural substrates discriminatively affect the proliferation and the immigration of Aurelia spp. polyps at laboratory. These observations suggest that, even in the natural environment, different materials and texture may influence the composition and the abundance of the fouling communities and the assemblages of polyps and, indirectly, have effects on the amounts of released medusae.
基金Supported by the Fundamental Research Funds for the Central Universities(GK261002145)Key Teaching Reform Research of Shaanxi Normal University in 2014(14JG07)Teacher Education Program of Shaanxi Normal University in 2014(JSJY2014J014)~~
文摘Based on field survey and research of Hanzhong, relocation of Nanzheng County was explored and the existing problems were analyzed. Furthermore, the re- gional characters of Nanzheng County were investigated to analyze the feasibility and necessity of relocation with lots of data and evaluation was made on relocation of Nanzheng County. In addition, the existing problems of relocation were concluded and the prospect of the county was discussed, which is of significance for relocation in Nanzheng County and even southern Shaanxi Province.
