Quantitative evaluation of the copepod feeding process is critical for understanding the functioning of marine food webs, as this provides a major link between primary producers and higher trophic levels. In this stud...Quantitative evaluation of the copepod feeding process is critical for understanding the functioning of marine food webs, as this provides a major link between primary producers and higher trophic levels. In this study, a molecular protocol based on quantitative polymerase chain reaction(qPCR) targeting 18S rDNA was developed and used to investigate the feeding and digestion rates of the copepod Acartia erythraea in a laboratory experiment using microalgae Thalassiosira weissflogii, Prorocentrum shikokuense, and Alexandrium catenella as prey. Although offered an equal encounter rate based on biovolume, prey uptake varied substantially among the three algal species, with the ingestion rate(IR) and digestion rate(DR) of A. erythraea differing significantly(P <0.001) based on both cell counting and qPCR detection. Acartia erythraea showed the highest IR(2.79×10~4 cells/(ind.·h)) and DR(2.43×10~4 cells/(ind.·h)) on T. weissflogii, and the lowest amounts of ingested P. shikokuense were detected. The highest assimilation rate(~90.64%, IR/DR) was observed in copepods fed with P. shikokuense. The qPCR method used here can help determine the digestion rate and assimilation rate of copepods by detecting cells remaining in the gut hence providing the possibility to examine trophic links involving key species in the marine ecosystem. Our results indicate that A. erythraea has diet-specific feeding performance in different processes, and a quantitative assessment of copepod feeding is needed to accurately determine its functional role in the energy and matter uptake from marine food webs.展开更多
Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity ...Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity is limited.The aim of this study is to identify the environmental factors that drive phyllosphere algal community composition and diversity in rainforests.For this purpose,we used single molecule real-time sequencing of full-length 18S rDNA to characterize the composition of phyllosphere microalgal communities growing on four host tree species(Ficus tikoua,Caryota mitis,Arenga pinnata,and Musa acuminata) common to three types of forest over four months at the Xishuangbanna Tropical Botanical Garden,Yunnan Province,China.Environmental 18S rDNA sequences revealed that the green algae orders Watanabeales and Trentepohliales were dominant in almost all algal communities and that phyllosphere algal species richness and biomass were lower in planted forest than in primeval and reserve rainforest.In addition,algal community composition differed significantly between planted forest and primeval rainforest.We also found that algal communities were affected by soluble reactive phosphorous,total nitrogen,and ammonium contents.Our findings indicate that algal community structure is significantly related to forest type and host tree species.Furthermore,this study is the first to identify environmental factors that affect phyllosphere algal communities,significantly contributing to future taxonomic research,especially for the green algae orders Watanabeales and Trentepohliales.This research also serves as an important reference for molecular diversity analysis of algae in other specific habitats,such as epiphytic algae and soil algae.展开更多
Sequences from a region of the nuclear ribosomal 18S rDNA gene of approximately 1 912 base pairs （bp） were used to generate a molecular phylogeny for the Pentatomomorpha based on 53 species representing 21 putative ...Sequences from a region of the nuclear ribosomal 18S rDNA gene of approximately 1 912 base pairs （bp） were used to generate a molecular phylogeny for the Pentatomomorpha based on 53 species representing 21 putative families. Phylogenetic analyses using the most parsimony method （MP）, maximum likelihood method （ML）, and neighbor joining method （NJ） showed strong support that the Pentatomomorpha lineage is a monophyly and the superfamily Aradoidea is a sister group to the remainder of the Pentatomomorpha （Trichophora）. The Trichophora could be divided into two clades ： one clade consisted of the monophyletic superfamilies Pentatomoidea and Pyrrhocoroidea; the other was mainly the polyphyletic superfamilies Lygaeoidea, Coreoidea and Idiostoloidea. The superfamilies Lygaeoidea and Coreoidea were both polyphyletic. Within Lygaeoidea, Piesmatidae was sister to Berytidae. They formed a clade locating at the basal of the Trichophora and distantly related to the other two families Lygaeidae and Rhyparochromidae. This research suggested that 18S rDNA was a proper marker to reconstruct the phylogeny of Pentatomomorpha that was accordant to morphological studies and the research of Li et al （2005）. The Pyrrhocoroidea was further divided from the Coreoidea （s./at ）. It was suggested that the Piesmatidae might be assigned as a superfamily of Pentatomomorpha rather than a family in Lygaeoidea.展开更多
[Objective] The aim was to isolate and identify a taxol-producing endophytic fungus from Taxus media. [Method] 32 strains of endophytic fungi were identified form the inner bark of T. media,and their fermentation prod...[Objective] The aim was to isolate and identify a taxol-producing endophytic fungus from Taxus media. [Method] 32 strains of endophytic fungi were identified form the inner bark of T. media,and their fermentation products were detected by high performance liquid chromatography (HPLC). [Result] Through the screening,a strain of taxol-producing endophytic fungi M57 was obtained,which could produce 45-50 μg/L of taxol,and M57 was defined as Rhizopus sp. through morphological observation and 18S rDNA sequence analysis. [Conclusion] The finding of Rhizopus sp. M57 provided a promising strain for producing taxol with taxol-producing fungi fermentation process.展开更多
基金The National Natural Science Foundation of China under contract Nos 41806188 and 42176118the Science and Technology Planning Project of Guangdong Province,China under contract No. 2020B1212060058the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) under contract No.GML2019ZD0404。
文摘Quantitative evaluation of the copepod feeding process is critical for understanding the functioning of marine food webs, as this provides a major link between primary producers and higher trophic levels. In this study, a molecular protocol based on quantitative polymerase chain reaction(qPCR) targeting 18S rDNA was developed and used to investigate the feeding and digestion rates of the copepod Acartia erythraea in a laboratory experiment using microalgae Thalassiosira weissflogii, Prorocentrum shikokuense, and Alexandrium catenella as prey. Although offered an equal encounter rate based on biovolume, prey uptake varied substantially among the three algal species, with the ingestion rate(IR) and digestion rate(DR) of A. erythraea differing significantly(P <0.001) based on both cell counting and qPCR detection. Acartia erythraea showed the highest IR(2.79×10~4 cells/(ind.·h)) and DR(2.43×10~4 cells/(ind.·h)) on T. weissflogii, and the lowest amounts of ingested P. shikokuense were detected. The highest assimilation rate(~90.64%, IR/DR) was observed in copepods fed with P. shikokuense. The qPCR method used here can help determine the digestion rate and assimilation rate of copepods by detecting cells remaining in the gut hence providing the possibility to examine trophic links involving key species in the marine ecosystem. Our results indicate that A. erythraea has diet-specific feeding performance in different processes, and a quantitative assessment of copepod feeding is needed to accurately determine its functional role in the energy and matter uptake from marine food webs.
基金supported by the National Natural Science Foundation of China (Grant no.31870189 and 32000168)。
文摘Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity is limited.The aim of this study is to identify the environmental factors that drive phyllosphere algal community composition and diversity in rainforests.For this purpose,we used single molecule real-time sequencing of full-length 18S rDNA to characterize the composition of phyllosphere microalgal communities growing on four host tree species(Ficus tikoua,Caryota mitis,Arenga pinnata,and Musa acuminata) common to three types of forest over four months at the Xishuangbanna Tropical Botanical Garden,Yunnan Province,China.Environmental 18S rDNA sequences revealed that the green algae orders Watanabeales and Trentepohliales were dominant in almost all algal communities and that phyllosphere algal species richness and biomass were lower in planted forest than in primeval and reserve rainforest.In addition,algal community composition differed significantly between planted forest and primeval rainforest.We also found that algal communities were affected by soluble reactive phosphorous,total nitrogen,and ammonium contents.Our findings indicate that algal community structure is significantly related to forest type and host tree species.Furthermore,this study is the first to identify environmental factors that affect phyllosphere algal communities,significantly contributing to future taxonomic research,especially for the green algae orders Watanabeales and Trentepohliales.This research also serves as an important reference for molecular diversity analysis of algae in other specific habitats,such as epiphytic algae and soil algae.
文摘Sequences from a region of the nuclear ribosomal 18S rDNA gene of approximately 1 912 base pairs （bp） were used to generate a molecular phylogeny for the Pentatomomorpha based on 53 species representing 21 putative families. Phylogenetic analyses using the most parsimony method （MP）, maximum likelihood method （ML）, and neighbor joining method （NJ） showed strong support that the Pentatomomorpha lineage is a monophyly and the superfamily Aradoidea is a sister group to the remainder of the Pentatomomorpha （Trichophora）. The Trichophora could be divided into two clades ： one clade consisted of the monophyletic superfamilies Pentatomoidea and Pyrrhocoroidea; the other was mainly the polyphyletic superfamilies Lygaeoidea, Coreoidea and Idiostoloidea. The superfamilies Lygaeoidea and Coreoidea were both polyphyletic. Within Lygaeoidea, Piesmatidae was sister to Berytidae. They formed a clade locating at the basal of the Trichophora and distantly related to the other two families Lygaeidae and Rhyparochromidae. This research suggested that 18S rDNA was a proper marker to reconstruct the phylogeny of Pentatomomorpha that was accordant to morphological studies and the research of Li et al （2005）. The Pyrrhocoroidea was further divided from the Coreoidea （s./at ）. It was suggested that the Piesmatidae might be assigned as a superfamily of Pentatomomorpha rather than a family in Lygaeoidea.
基金Supported by National Natural Science Foundation of China(20776058)New Century Training Programme Foundation for the Talents by the State Education Commission (NCET-06-0646)~~
文摘[Objective] The aim was to isolate and identify a taxol-producing endophytic fungus from Taxus media. [Method] 32 strains of endophytic fungi were identified form the inner bark of T. media,and their fermentation products were detected by high performance liquid chromatography (HPLC). [Result] Through the screening,a strain of taxol-producing endophytic fungi M57 was obtained,which could produce 45-50 μg/L of taxol,and M57 was defined as Rhizopus sp. through morphological observation and 18S rDNA sequence analysis. [Conclusion] The finding of Rhizopus sp. M57 provided a promising strain for producing taxol with taxol-producing fungi fermentation process.
