In terrestrial ecosystems,deep soils(below 30 cm)are major organic carbon(C)pools.The labile carbon input could alter soil organic carbon(SOC)mineralization,resulting in priming effect(PE),which could be modified by n...In terrestrial ecosystems,deep soils(below 30 cm)are major organic carbon(C)pools.The labile carbon input could alter soil organic carbon(SOC)mineralization,resulting in priming effect(PE),which could be modified by nitrogen(N)availability,however,the underlying mechanism is unclear for deep soils,which complicates the prediction of deep soil C cycling in response to N deposition.A series of N applications with ^(13)C labeled glucose was set to investigate the effect of labile C and N on deep SOC mineralization.Microbial biomass,functional community,metabolic efficiency and enzyme activities were examined for their effects on SOC mineralization and PE.During incubation,glucose addition promoted SOC mineralization,resulting in positive PE.The magnitude of PE decreased significantly with increasing N.The N-regulated PE was not dependent on extracellular enzyme activities but was positively correlated with carbon use efficiency and negatively with metabolic quotient.Higher N levels resulted in higher microbial biomass and SOC-derived microbial biomass than lower N levels.These results suggest that the decline in the PE under high N availability was mainly controlled by higher microbial metabolic efficiency which allocated more C for growth.Structural equation modelling also revealed that microbial metabolic efficiency rather than enzyme activities was the main factor regulating the PE.The negative effect of additional N suggests that future N deposition could promote soil C sequestration.展开更多
目的探讨乳腺癌易感基因相互作用蛋白1(BRCA1 interacting protein C-terminal helicase 1,BRIP1)基因功能区4个单核苷酸多态性(single nucleotide polymorphisms,SNPs)位点与习惯性流产的相关性。方法严格按照诊断标准,采集无关习惯性...目的探讨乳腺癌易感基因相互作用蛋白1(BRCA1 interacting protein C-terminal helicase 1,BRIP1)基因功能区4个单核苷酸多态性(single nucleotide polymorphisms,SNPs)位点与习惯性流产的相关性。方法严格按照诊断标准,采集无关习惯性流产患者291例(病例组)、健康对照组281例(对照组)外周静脉血,提取基因组DNA,采用基质辅助激光解吸电离飞行时间质谱技术对4个SNPs位点进行分型;采用SPSS 20.0及Haploview4.2软件分析位点基因型、等位基因及单倍型频率分布及两组间的差异。结果 BRIP1基因外显子18 rs4986764位点病例组CC基因型频率明显高于对照组(χ^2=6.469,P=0.039);病例组C等位基因频率明显高于对照组(χ^2=4.893,P=0.027, OR =1.330,95% CI =1.033~1.714)。连锁不平衡分析表明,由rs11079454-rs4986763-rs494986764构成的单倍型高度连锁(D >0.9,r 2 >0.8),对照组T-T-T单倍型频率明显高于病例组(χ^2=8.043,P=0.005, OR =0.565,95% CI =0.381~0.840);病例组T-C-C单倍型频率明显高于对照组(χ^2=4.392,P=0.036, OR =1.540,95% CI =1.027~ 2.310 )。结论 BRIP1基因第18外显子rs4986764位点可能与习惯性流产有关,携带有C等位基因的个体可能更容易习惯性流产。展开更多
Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand...Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand forest carbon cycling.Methods We compared lignin content and chemical signature in three soil depths of four major plant communities in a subtropical forest,which located in the north part of Wuling Mountains,China.Lignin was measured using CuO oxidation method.Important Findings Both lignin content and its biochemical signature in plant litter varied among communities.However,these differences were mostly no longer exist in the upper soil layers.Lignin chemistry in soils inherited some of the biochemical signature of lignin in litter,but in a diminished magnitude.these results suggest that different plant communities had similar decomposition process with vary-ing rates,caused diminished differences in lignin content and its biochemical signature.Lignin content decreased with soil depth,but the biochemical signature of lignin was not significantly dif-ferent among soil layers for all communities,which suggests that vertical movement of lignin within the soil profile is very likely a key process causing this similar biochemical signature.these results emphasized the important roles of lignin inputs and soil eluviation in shaping lignin characteristics and distribution in forest soils,which pinpoint the urgent need to consider hydrological processes in studying forest soil carbon cycling.展开更多
基金supported by the Natural Science Foundation of China(Grant numbers 31870465,31600377,31700462).
文摘In terrestrial ecosystems,deep soils(below 30 cm)are major organic carbon(C)pools.The labile carbon input could alter soil organic carbon(SOC)mineralization,resulting in priming effect(PE),which could be modified by nitrogen(N)availability,however,the underlying mechanism is unclear for deep soils,which complicates the prediction of deep soil C cycling in response to N deposition.A series of N applications with ^(13)C labeled glucose was set to investigate the effect of labile C and N on deep SOC mineralization.Microbial biomass,functional community,metabolic efficiency and enzyme activities were examined for their effects on SOC mineralization and PE.During incubation,glucose addition promoted SOC mineralization,resulting in positive PE.The magnitude of PE decreased significantly with increasing N.The N-regulated PE was not dependent on extracellular enzyme activities but was positively correlated with carbon use efficiency and negatively with metabolic quotient.Higher N levels resulted in higher microbial biomass and SOC-derived microbial biomass than lower N levels.These results suggest that the decline in the PE under high N availability was mainly controlled by higher microbial metabolic efficiency which allocated more C for growth.Structural equation modelling also revealed that microbial metabolic efficiency rather than enzyme activities was the main factor regulating the PE.The negative effect of additional N suggests that future N deposition could promote soil C sequestration.
文摘目的探讨乳腺癌易感基因相互作用蛋白1(BRCA1 interacting protein C-terminal helicase 1,BRIP1)基因功能区4个单核苷酸多态性(single nucleotide polymorphisms,SNPs)位点与习惯性流产的相关性。方法严格按照诊断标准,采集无关习惯性流产患者291例(病例组)、健康对照组281例(对照组)外周静脉血,提取基因组DNA,采用基质辅助激光解吸电离飞行时间质谱技术对4个SNPs位点进行分型;采用SPSS 20.0及Haploview4.2软件分析位点基因型、等位基因及单倍型频率分布及两组间的差异。结果 BRIP1基因外显子18 rs4986764位点病例组CC基因型频率明显高于对照组(χ^2=6.469,P=0.039);病例组C等位基因频率明显高于对照组(χ^2=4.893,P=0.027, OR =1.330,95% CI =1.033~1.714)。连锁不平衡分析表明,由rs11079454-rs4986763-rs494986764构成的单倍型高度连锁(D >0.9,r 2 >0.8),对照组T-T-T单倍型频率明显高于病例组(χ^2=8.043,P=0.005, OR =0.565,95% CI =0.381~0.840);病例组T-C-C单倍型频率明显高于对照组(χ^2=4.392,P=0.036, OR =1.540,95% CI =1.027~ 2.310 )。结论 BRIP1基因第18外显子rs4986764位点可能与习惯性流产有关,携带有C等位基因的个体可能更容易习惯性流产。
基金This study was supported by the National Natural Science Foundation of China(31270515,31400463)the Chinese National Key Development Program for Basic Research(2014CB954004).
文摘Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand forest carbon cycling.Methods We compared lignin content and chemical signature in three soil depths of four major plant communities in a subtropical forest,which located in the north part of Wuling Mountains,China.Lignin was measured using CuO oxidation method.Important Findings Both lignin content and its biochemical signature in plant litter varied among communities.However,these differences were mostly no longer exist in the upper soil layers.Lignin chemistry in soils inherited some of the biochemical signature of lignin in litter,but in a diminished magnitude.these results suggest that different plant communities had similar decomposition process with vary-ing rates,caused diminished differences in lignin content and its biochemical signature.Lignin content decreased with soil depth,but the biochemical signature of lignin was not significantly dif-ferent among soil layers for all communities,which suggests that vertical movement of lignin within the soil profile is very likely a key process causing this similar biochemical signature.these results emphasized the important roles of lignin inputs and soil eluviation in shaping lignin characteristics and distribution in forest soils,which pinpoint the urgent need to consider hydrological processes in studying forest soil carbon cycling.
