DNA methylation is an important epigenetic regulatory mechanism that influences genomic stability, gene activation, X-chromosome inactivation and other factors. A change in DNA methylation is usually associated with a...DNA methylation is an important epigenetic regulatory mechanism that influences genomic stability, gene activation, X-chromosome inactivation and other factors. A change in DNA methylation is usually associated with aging and cellular senescence. DNA methyltransferase 1(DNMT1) is the most abundant DNA methyltransferase, and it plays an important role in maintaining the established methylation pattern during DNA replication in vertebrates. Although the effect of aging on DNA methylation has been well studied in vertebrates, little research has been conducted in invertebrates, especially in marine bivalves. In this study, we examined global DNA methylation levels in four groups of adult Zhikong scallop Chlamys farreri at different ages. The results showed that both the age and tissue type had a strong effect on the DNA methylation. In addition, a significant decrease in DNA methylation with aging(1–4 years) can be detected in mantle, kidney and hepatopancreas. We further measured the change in DNMT1 transcript abundance using quantitative reverse transcription PCR(q RT-PCR), which revealed that DNMT1 transcription significantly decreased with aging in mantle and hepatopancreas and strongly correlated with DNA methylation(R = 0.72). Our data provided greater insight into the aging-related decline of DNA methylation, which could aid in gaining a better understanding of the relationship between DNA methylation and the aging process in bivalve mollusks.展开更多
The ocean environment is protected from oil pollution usually by using floating booms,which involves water-oil two-phase flow and strong fluid-structure interaction.In this paper,a modified multi-phase smoothed partic...The ocean environment is protected from oil pollution usually by using floating booms,which involves water-oil two-phase flow and strong fluid-structure interaction.In this paper,a modified multi-phase smoothed particle hydrodynamics(SPH) method is proposed to model oil spill containment by using a moving boom.Four major influencing factors including oil type,moving velocity and skirt angle of the boom,and water wave are investigated.The SPH simulation results demonstrate different typical boom failure modes found in laboratory experiments.It is shown that the ability of a boom in containing oil is not only affected by its own characteristics,but also closely related to external environmental factors.It is found that boom failure is more likely to happen for heavy oil,high boom velocity,negative skirt angle,and/or in the presence of water waves.展开更多
基金supported by the National Natural Science Foundation of China(31130054)the National High Technology Research and Development Program of China(2012AA10A401)Doctoral Fund of Ministry of Education of China(20120132130002)
文摘DNA methylation is an important epigenetic regulatory mechanism that influences genomic stability, gene activation, X-chromosome inactivation and other factors. A change in DNA methylation is usually associated with aging and cellular senescence. DNA methyltransferase 1(DNMT1) is the most abundant DNA methyltransferase, and it plays an important role in maintaining the established methylation pattern during DNA replication in vertebrates. Although the effect of aging on DNA methylation has been well studied in vertebrates, little research has been conducted in invertebrates, especially in marine bivalves. In this study, we examined global DNA methylation levels in four groups of adult Zhikong scallop Chlamys farreri at different ages. The results showed that both the age and tissue type had a strong effect on the DNA methylation. In addition, a significant decrease in DNA methylation with aging(1–4 years) can be detected in mantle, kidney and hepatopancreas. We further measured the change in DNMT1 transcript abundance using quantitative reverse transcription PCR(q RT-PCR), which revealed that DNMT1 transcription significantly decreased with aging in mantle and hepatopancreas and strongly correlated with DNA methylation(R = 0.72). Our data provided greater insight into the aging-related decline of DNA methylation, which could aid in gaining a better understanding of the relationship between DNA methylation and the aging process in bivalve mollusks.
基金supported by the National Natural Science Foundation of China (Grant No. 11172306)the Program of "One Hundred Talented People" of the Chinese Academy of Sciences
文摘The ocean environment is protected from oil pollution usually by using floating booms,which involves water-oil two-phase flow and strong fluid-structure interaction.In this paper,a modified multi-phase smoothed particle hydrodynamics(SPH) method is proposed to model oil spill containment by using a moving boom.Four major influencing factors including oil type,moving velocity and skirt angle of the boom,and water wave are investigated.The SPH simulation results demonstrate different typical boom failure modes found in laboratory experiments.It is shown that the ability of a boom in containing oil is not only affected by its own characteristics,but also closely related to external environmental factors.It is found that boom failure is more likely to happen for heavy oil,high boom velocity,negative skirt angle,and/or in the presence of water waves.
