Ten previously undescribed rearranged 4,9-friedodrimane merosesquiterpenoids,designated ircinrimanes A-J(1-10),were isolated from the marine sponge Ircinia sp.,collected from the South China Sea.Their structures and a...Ten previously undescribed rearranged 4,9-friedodrimane merosesquiterpenoids,designated ircinrimanes A-J(1-10),were isolated from the marine sponge Ircinia sp.,collected from the South China Sea.Their structures and absolute configurations were definitively elucidated through a combination of spectroscopic data analysis,DP4+probability assessments,electronic circular dichroism(ECD)calculations,and Mo2(OAc)4 experiment.Compounds 1-4contained benzene rings,with compound 1 featuring an unusual 2-carbonyl morpholin ring,while compound 2 possessed a benzoxazole ring.Compounds 5-9 comprised sesquiterpenoid quinones with distinct amino side chains at C-20,and compound 10 incorporated an ethoxy side chain.Notably,compounds 1-10 demonstrated an unusual rearrangement of 4,9-friedodrimane sesquiterpenes.Compounds 2,5-8 and 10 demonstrated cytotoxic activity,while compound 2 exhibited anti-inflammatory activity in zebrafish.展开更多
Background Subtropical forests play a critical role in global carbon cycling but are highly sensitive to climate-d riven precipitation and temperature variability.At China's Dinghushan Biosphere Reserve,observed w...Background Subtropical forests play a critical role in global carbon cycling but are highly sensitive to climate-d riven precipitation and temperature variability.At China's Dinghushan Biosphere Reserve,observed warming(+1.5℃since 2002)and precipitation declines(8.2±1.3 mm/yr)exceed global subtropical averages,yet their combined effects on water-use efficiency(WUE)and carbon exchange remain poorly quantified.Methods Using 21 years of eddy covariance and meteorological data(2002-2022),we analyzed WUE(defined as NEE/ET;g C kg^(-1)H_(2)O)responses to drought events classified via the standardized precipitation index(SPI).Results The reserve experienced increasing drought frequency,with 7 extreme droughts(SPI≤-2.0)post-2010versus 2 pre-2010.Soil moisture extremes(<0.15 m^(3)m^(-3))reduced WUE by 2.35 g C kg^(-1)H_(2)O.Carbon fluxes showed diffe rential sensitivity:ecosystem respiration(RE)declined most sharply(-71.9×10^(-5)g C m^(-2)s^(-1))during extreme droughts,while gross primary productivity(GPP)exhibited non-linear reductions below a 1,200 mm yr^(-1)precipitation threshold.Late-successional forests maintained 0.94 g C kg^(-1)H_(2)O higher WUE than mid-successional stands during droughts,linked to deeper rooting systems(120±15 cm).The identified 3-year recovery lag suggests targeted reforestation during wet intervals(SPI≥1.5)could enhance resilience.Conclusion By establishing quantitative drought thresholds and revealing hydraulic versus non-hydraulic limitations,our findings provide actionable strategies for subtropical forest conservation under climate change.展开更多
Comprehensive Summary Seven new kalihinene diterpenoids,kalihioxepanes A-G(1-7)bearing a rare oxepane ring,were isolated from sponge Acanthella cavernosa collected from the South China Sea.The structures and absolute ...Comprehensive Summary Seven new kalihinene diterpenoids,kalihioxepanes A-G(1-7)bearing a rare oxepane ring,were isolated from sponge Acanthella cavernosa collected from the South China Sea.The structures and absolute configurations were elucidated by comprehensive spectroscopic analysis,single crystal X-ray diffraction,and quantum chemical calculation methods.Kalihioxepane A(1)displayed strong cytotoxicity against H69 and K562 tumor cells,while kalihioxepane B(2)showed moderate cytotoxicity against K562 cells.展开更多
Over the past 2 to 3 decades,Chinese forests are estimated to act as a large carbon sink,yet the magnitude and spatial patterns of this sink differ considerably among studies.Using 3 microwave(L-and X-band vegetation ...Over the past 2 to 3 decades,Chinese forests are estimated to act as a large carbon sink,yet the magnitude and spatial patterns of this sink differ considerably among studies.Using 3 microwave(L-and X-band vegetation optical depth[VOD])and 3 optical(normalized difference vegetation index,leaf area index,and tree cover)remote-sensing vegetation products,this study compared the estimated live woody aboveground biomass carbon(AGC)dynamics over China between 2013 and 2019.Our results showed that tree cover has the highest spatial consistency with 3 published AGC maps(mean correlation value R=0.84),followed by L-VOD(R=0.83),which outperform the other VODs.An AGC estimation model was proposed to combine all indices to estimate the annual AGC dynamics in China during 2013 to 2019.The performance of the AGC estimation model was good(root mean square error=0.05 Pg C and R^(2)=0.90 with a mean relative uncertainty of 9.8% at pixel scale[0.25°]).Results of the AGC estimation model showed that carbon uptake by the forests in China was about+0.17 Pg C year^(-1) from 2013 to 2019.At the regional level,provinces in southwest China including Guizhou(+22.35 Tg C year^(-1)),Sichuan(+14.49 Tg C year^(-1)),and Hunan(+11.42 Tg C year^(-1))provinces had the highest carbon sink rates during 2013 to 2019.Most of the carbon-sink regions have been afforested recently,implying that afforestation and ecological engineering projects have been effective means for carbon sequestration in these regions.展开更多
Backgroundand Originality Content,Cembranoids are a structurally diverse class of diterpenoids commonly occurring in marine and terrestrial organisms.(+)-Cembrene was the first reported cembranoid diterpenoid discover...Backgroundand Originality Content,Cembranoids are a structurally diverse class of diterpenoids commonly occurring in marine and terrestrial organisms.(+)-Cembrene was the first reported cembranoid diterpenoid discovered in 1962,l and more than 1400 cembranoid diterpenoids have been identified in the last six decades,[2]Cembranoids are characterized by a 14-membered carbocyclic ring,an isopropyl group and three methyl groups,which form their core carbon skeleton.Enzymatic processes such as oxidation,oxidative rearrangements and transannular cyclizations occur in organisms,leading to the formation of distinctive specialized metabolites such as epoxide,lactone,ester,furan,pyrane and other ringbased cembranoids.[2-3]展开更多
Thirteen new nitrogen-containing nardosinane-type sesquiterpenoids,clavukoelloids A-M(1-13)with unique acrylamide fragments vs.the reported general nardosinane-type sesquiterpenoids containing lactone,were isolated fr...Thirteen new nitrogen-containing nardosinane-type sesquiterpenoids,clavukoelloids A-M(1-13)with unique acrylamide fragments vs.the reported general nardosinane-type sesquiterpenoids containing lactone,were isolated from the soft coral Clavularia koellikeri collected from the South China Sea.The structures and absolute configurations of new compounds were unambiguously determined by analysis of spectroscopic data,CP3,DP4+,ECD spectra,and X-ray diffraction.Compound 6 showed anti-inflammatory activities and hepatoprotective activities in transgenic fluorescent zebrafish.展开更多
The mutual interdependence of plants and arbuscular mycorrhizal fungi(AMF)is important in carbon and mineral nutrient exchange.However,an understanding of how AMF community assemblies vary in different forests and the...The mutual interdependence of plants and arbuscular mycorrhizal fungi(AMF)is important in carbon and mineral nutrient exchange.However,an understanding of how AMF community assemblies vary in different forests and the underlying factors regulating AMF diversity in native tropical forests is largely unknown.We explored the AMF community assembly and the underlying factors regulating AMF diversity in a young(YF)and an old-growth forest(OF)in a tropical area.The results showed that a total of 53 AMF phylogroups(virtual taxa,VTs)were detected,38±1 in the OF and 34±1 in the YF through high-throughput sequencing of 18S rDNA,and AMF community composition was significantly different between the two forests.A structural equation model showed that the forest traits indirectly influenced AMF diversity via the plant community,soil properties and microbes,which explained 44.2%of the total observed variation in AMF diversity.Plant diversity and biomass were the strongest predictors of AMF diversity,indicating that AMF diversity was dominantly regulated by biotic factors at our study sites.Our study indicated that forest community traits have a predictable effect on the AMF community;plant community traits and soil properties are particularly important for determining AMF diversity in tropical forests.展开更多
基金supported by National Key R&D Program of China(No.2022YFC2804100)Qingdao Marine Science and Technology Center(No.2022QNLM030003-1)+2 种基金Qingdao postdoctoral project(No.QDBSH20240102034)Shandong Postdoctoral Science Foundation(No.SDCX-ZG-202400077)National Natural Science Foundation of China(No.U2006204)。
文摘Ten previously undescribed rearranged 4,9-friedodrimane merosesquiterpenoids,designated ircinrimanes A-J(1-10),were isolated from the marine sponge Ircinia sp.,collected from the South China Sea.Their structures and absolute configurations were definitively elucidated through a combination of spectroscopic data analysis,DP4+probability assessments,electronic circular dichroism(ECD)calculations,and Mo2(OAc)4 experiment.Compounds 1-4contained benzene rings,with compound 1 featuring an unusual 2-carbonyl morpholin ring,while compound 2 possessed a benzoxazole ring.Compounds 5-9 comprised sesquiterpenoid quinones with distinct amino side chains at C-20,and compound 10 incorporated an ethoxy side chain.Notably,compounds 1-10 demonstrated an unusual rearrangement of 4,9-friedodrimane sesquiterpenes.Compounds 2,5-8 and 10 demonstrated cytotoxic activity,while compound 2 exhibited anti-inflammatory activity in zebrafish.
基金funded by the National Key R&D Program of China[No.2024YFF1306600]the National Natural Science Foundation of China[31961143023]+3 种基金the Dinghushan Forest Ecosystem Positioning Research Station of the National Science and Technology Infrastructure Platformthe Chinese Ecosystem Research Network(CERN)the Operation Service Project of the National Scientific Observation and Research Field Station of the Dinghushan Forest Ecosystem of Guangdongthe Ministry of Science and Technology of the People’s Republic of China
文摘Background Subtropical forests play a critical role in global carbon cycling but are highly sensitive to climate-d riven precipitation and temperature variability.At China's Dinghushan Biosphere Reserve,observed warming(+1.5℃since 2002)and precipitation declines(8.2±1.3 mm/yr)exceed global subtropical averages,yet their combined effects on water-use efficiency(WUE)and carbon exchange remain poorly quantified.Methods Using 21 years of eddy covariance and meteorological data(2002-2022),we analyzed WUE(defined as NEE/ET;g C kg^(-1)H_(2)O)responses to drought events classified via the standardized precipitation index(SPI).Results The reserve experienced increasing drought frequency,with 7 extreme droughts(SPI≤-2.0)post-2010versus 2 pre-2010.Soil moisture extremes(<0.15 m^(3)m^(-3))reduced WUE by 2.35 g C kg^(-1)H_(2)O.Carbon fluxes showed diffe rential sensitivity:ecosystem respiration(RE)declined most sharply(-71.9×10^(-5)g C m^(-2)s^(-1))during extreme droughts,while gross primary productivity(GPP)exhibited non-linear reductions below a 1,200 mm yr^(-1)precipitation threshold.Late-successional forests maintained 0.94 g C kg^(-1)H_(2)O higher WUE than mid-successional stands during droughts,linked to deeper rooting systems(120±15 cm).The identified 3-year recovery lag suggests targeted reforestation during wet intervals(SPI≥1.5)could enhance resilience.Conclusion By establishing quantitative drought thresholds and revealing hydraulic versus non-hydraulic limitations,our findings provide actionable strategies for subtropical forest conservation under climate change.
基金This work was supported by the National Natural Science Foundation of China(Nos.U2006204,41776136,2181101213,81991522,and 41876161)。
文摘Comprehensive Summary Seven new kalihinene diterpenoids,kalihioxepanes A-G(1-7)bearing a rare oxepane ring,were isolated from sponge Acanthella cavernosa collected from the South China Sea.The structures and absolute configurations were elucidated by comprehensive spectroscopic analysis,single crystal X-ray diffraction,and quantum chemical calculation methods.Kalihioxepane A(1)displayed strong cytotoxicity against H69 and K562 tumor cells,while kalihioxepane B(2)showed moderate cytotoxicity against K562 cells.
基金supported by the National Science Fund for Distinguished Young Scholars(41825020)the National Natural Science Foundation of China(42171339)+1 种基金the Postdoctoral Start-Up Project of Southwest University(SWU020016)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05050200).
文摘Over the past 2 to 3 decades,Chinese forests are estimated to act as a large carbon sink,yet the magnitude and spatial patterns of this sink differ considerably among studies.Using 3 microwave(L-and X-band vegetation optical depth[VOD])and 3 optical(normalized difference vegetation index,leaf area index,and tree cover)remote-sensing vegetation products,this study compared the estimated live woody aboveground biomass carbon(AGC)dynamics over China between 2013 and 2019.Our results showed that tree cover has the highest spatial consistency with 3 published AGC maps(mean correlation value R=0.84),followed by L-VOD(R=0.83),which outperform the other VODs.An AGC estimation model was proposed to combine all indices to estimate the annual AGC dynamics in China during 2013 to 2019.The performance of the AGC estimation model was good(root mean square error=0.05 Pg C and R^(2)=0.90 with a mean relative uncertainty of 9.8% at pixel scale[0.25°]).Results of the AGC estimation model showed that carbon uptake by the forests in China was about+0.17 Pg C year^(-1) from 2013 to 2019.At the regional level,provinces in southwest China including Guizhou(+22.35 Tg C year^(-1)),Sichuan(+14.49 Tg C year^(-1)),and Hunan(+11.42 Tg C year^(-1))provinces had the highest carbon sink rates during 2013 to 2019.Most of the carbon-sink regions have been afforested recently,implying that afforestation and ecological engineering projects have been effective means for carbon sequestration in these regions.
基金supported by the National Natural Science Foundation of China(No.U2006204).
文摘Backgroundand Originality Content,Cembranoids are a structurally diverse class of diterpenoids commonly occurring in marine and terrestrial organisms.(+)-Cembrene was the first reported cembranoid diterpenoid discovered in 1962,l and more than 1400 cembranoid diterpenoids have been identified in the last six decades,[2]Cembranoids are characterized by a 14-membered carbocyclic ring,an isopropyl group and three methyl groups,which form their core carbon skeleton.Enzymatic processes such as oxidation,oxidative rearrangements and transannular cyclizations occur in organisms,leading to the formation of distinctive specialized metabolites such as epoxide,lactone,ester,furan,pyrane and other ringbased cembranoids.[2-3]
基金supported by the National Natural Science Foundation of China(Nos.U2006204,41776136,and 2181101213)。
文摘Thirteen new nitrogen-containing nardosinane-type sesquiterpenoids,clavukoelloids A-M(1-13)with unique acrylamide fragments vs.the reported general nardosinane-type sesquiterpenoids containing lactone,were isolated from the soft coral Clavularia koellikeri collected from the South China Sea.The structures and absolute configurations of new compounds were unambiguously determined by analysis of spectroscopic data,CP3,DP4+,ECD spectra,and X-ray diffraction.Compound 6 showed anti-inflammatory activities and hepatoprotective activities in transgenic fluorescent zebrafish.
基金the National Natural Science Foundation of China(31770491,31270499 and 41430529)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0408)the Youth Innovation Promotion Association,CAS and Natural Science Foundation of Guangdong Province of China(2019A1515011486)。
文摘The mutual interdependence of plants and arbuscular mycorrhizal fungi(AMF)is important in carbon and mineral nutrient exchange.However,an understanding of how AMF community assemblies vary in different forests and the underlying factors regulating AMF diversity in native tropical forests is largely unknown.We explored the AMF community assembly and the underlying factors regulating AMF diversity in a young(YF)and an old-growth forest(OF)in a tropical area.The results showed that a total of 53 AMF phylogroups(virtual taxa,VTs)were detected,38±1 in the OF and 34±1 in the YF through high-throughput sequencing of 18S rDNA,and AMF community composition was significantly different between the two forests.A structural equation model showed that the forest traits indirectly influenced AMF diversity via the plant community,soil properties and microbes,which explained 44.2%of the total observed variation in AMF diversity.Plant diversity and biomass were the strongest predictors of AMF diversity,indicating that AMF diversity was dominantly regulated by biotic factors at our study sites.Our study indicated that forest community traits have a predictable effect on the AMF community;plant community traits and soil properties are particularly important for determining AMF diversity in tropical forests.
