Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it...Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.展开更多
DNA结合单锌指(DNA binding with one finger,Dof)是植物所特有的转录因子,主要参与调控植物的生长发育、抗逆和品质等生命活动过程。为了鉴定美洲南瓜Dof基因家族成员和探究其表达模式,从全基因组水平筛选和分析了美洲南瓜CpDof家族成...DNA结合单锌指(DNA binding with one finger,Dof)是植物所特有的转录因子,主要参与调控植物的生长发育、抗逆和品质等生命活动过程。为了鉴定美洲南瓜Dof基因家族成员和探究其表达模式,从全基因组水平筛选和分析了美洲南瓜CpDof家族成员、基因结构、蛋白保守基序和亲缘关系等,同时,通过转录组和荧光定量技术比较了不同成员在美洲南瓜中的时空表达与果实发育表达特性。结果表明,在美洲南瓜中存在58个Dof基因并广泛分布于全基因组;功能域Motif 1存在于所有的Dof基因中;其启动子序列中含有光响应、激素响应和防御应激等顺式作用元件;Dof基因在美洲南瓜中具有组织表达特异性和时空表达特异性。基于转录组和荧光定量验证结果,表明CpDof7、CpDof30和CpDof42等基因与美洲南瓜356和296果实发育密切相关。以上结果为进一步克隆和解析南瓜属Dof基因功能提供了有力支撑。展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030003).
文摘Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.
文摘DNA结合单锌指(DNA binding with one finger,Dof)是植物所特有的转录因子,主要参与调控植物的生长发育、抗逆和品质等生命活动过程。为了鉴定美洲南瓜Dof基因家族成员和探究其表达模式,从全基因组水平筛选和分析了美洲南瓜CpDof家族成员、基因结构、蛋白保守基序和亲缘关系等,同时,通过转录组和荧光定量技术比较了不同成员在美洲南瓜中的时空表达与果实发育表达特性。结果表明,在美洲南瓜中存在58个Dof基因并广泛分布于全基因组;功能域Motif 1存在于所有的Dof基因中;其启动子序列中含有光响应、激素响应和防御应激等顺式作用元件;Dof基因在美洲南瓜中具有组织表达特异性和时空表达特异性。基于转录组和荧光定量验证结果,表明CpDof7、CpDof30和CpDof42等基因与美洲南瓜356和296果实发育密切相关。以上结果为进一步克隆和解析南瓜属Dof基因功能提供了有力支撑。
