Increased carbonic anhydrase activity in Friend erythroleukemia cells during DMSO-stimulated erythroid differentiation and its inhibition by BrdU.

Carbonic anhydrase activity is increased in Friend erythroleukemia (FL) cells during the enhancement of erythroid differentiation in the presence of dimethylsulfoxide (DMSO) or butyric acid. Untreated FL cells show an increase in enzyme activity associated with logarithmic growth. The increase in the specific activity of carbonic anhydrase in the differentiating treated cells, however, appears to be due to at least two additional general mechanisms: (1) an induction of carbonic anhydrase paralleling the stimulation of hemoglobin synthesis and (2) the stability and/or retention of active carbonic anhydrase as compared to most of the other cell proteins. The stimulation of carbonic anhydrase activity in the treated cells is inhibited by 5-bromo-2'-deoxyuridine (BrdU). This is the first demonstration of BrdU inhibition of a DMSO induced product not directly related to hemoglobin.     

土壤有机碳汇内涵与核算方法辨析

在"碳达峰、碳中和"战略需求下,土壤有机碳汇作为生态系统碳汇的重要组成部分,土壤碳库容量以及如何开展土壤有机碳汇核算日益成为生态碳汇的研究热点。梳理了国内外土壤有机碳汇及核算相关研究成果,解析了土壤有机碳汇的概念内涵,提出了以稳定性有机碳作为土壤有机碳汇的表征指标及获取方法。从土壤发生学角度提出了土壤碳汇阈值的概念,土壤中有机碳的含量随着分解转化最终会达到动态平衡,此时稳定有机碳含量值约是常数,这个常数就是稳定碳库的库容,在特定的成土因素下,碳库的核算值不会超过平衡时的常态值。在客观上,体现在非人类干扰状态下不同土壤类型自然状态下的稳定性有机碳含量。参照土壤有机质平衡理论,提出了土壤碳汇核算的定量化方法,为土壤碳汇的度量和核算提供了一套技术思路。下一步土壤有机碳汇的核算应在科学研究基础上多角度凝聚共识,制定碳汇核算标准,确定不同尺度下可操作、可重复以及可复制的土壤有机碳汇核算技术与方法。