砷对烤烟(Nicotiana tabacum L.)碳代谢的影响

采用盆栽试验,系统地研究了砷对烤烟全生育期碳代谢及其过程的影响,结果表明,砷降低了烤烟整个生育期的叶绿素含量、光合速率、蔗糖合成酶（SS,合成方向）活性和现蕾以后的蔗糖磷酸合成酶（SPS）活性,提高了全生育期的SS（分解方向）活性和可溶性糖含量,因而抑制了碳的同化和蔗糖的合成,促进了蔗糖的分解,不利于碳向积累方向转化。砷提高了全生育期的腺苷二磷酸葡萄糖焦磷酸化酶（ADPG-PPase）活性,增加了团棵期和现蕾期淀粉的积累,降低了团棵期和采收期的可溶性淀粉酶（SSS）活性和采收期的淀粉含量,从而导致了碳积累代谢的紊乱,最终造成碳积累的减少。     

膜上斑点洁显示人红细胞b_5还原酶活性

人红细胞ＮＡＤＨ－细胞色素ｂ５还原酶是使高铁血红蛋白还原的主要酶类,其缺陷将导致遗传性高铁血红蛋白血症．目前,主要通过分光光度法测定ｂ５还原酶活性．我们将ｂ５还原酶抗体点于硝酸纤维膜上,以此捕获并富集红细胞胞浆ｂ５还原酶．有ｂ５还原酶活性的斑点用噻唑蓝染色．此法简单直观,可用于ｂ５还原酶的定性和半定量测定,为遗传性高铁血红蛋白血症的诊断提供了一种新的实验手段．     

原核生物核糖核酸酶HII基因的克隆及在大肠杆菌中的高效表达

核糖核酸酶HII (RNaseHII)能有效降解RNA和DNA杂交链中的RNA链。为进一步研究其功能 ,利用大肠杆菌XL1blue为模板 ,相应的寡聚脱氧核苷酸为引物 ,PCR扩增大肠杆菌RNaseHII(rnh 2 )基因 ,并将目的基因连接到克隆载体 pUC18上 ,经测序确认无误 ,分别亚克隆到能够进行IPTG诱导的表达载体pTrcHisC和进行温度诱导的表达载体pBV2 2 0上。重组质粒转化到大肠杆菌DH5α细胞中获得高效表达。在载体pTrcHisC和 pBV2 2 0中目的蛋白RNaseHII的表达量均超过菌体总蛋白的 2 0 % ,且表达产物以稳定的包涵体形式存在。此项工作为以后目的蛋白的纯化提供了有利条件 ,并为研究其结构和功能奠定了基础。     

SARS-CoV-2-induced Overexpression of miR-4485 Suppresses Osteogenic Differentiation and Impairs Fracture Healing

The angiotensin-converting enzyme 2 (ACE2) receptor has been identified as the cell entry point for SARS-CoV-2. Although ACE2 receptors are present in the bone marrow, the effects of SARS-CoV-2 on the biological activity of bone tissue have not yet been elucidated. In the present study we sought to investigate the impact of SARS-CoV-2 on osteoblastic activity in the context of fracture healing. MicroRNA-4485 (miR-4485), which we found to be upregulated in COVID-19 patients, negatively regulates osteogenic differentiation. We demonstrate this effect both in vitro and in vivo. Moreover, we identified the toll-like receptor 4 (TLR-4) as the potential target gene of miR-4485, and showed that reduction of TLR-4 induced by miR-4485 suppresses osteoblastic differentiation in vitro. Taken together, our findings highlight that up-regulation of miR-4485 is responsible for the suppression of osteogenic differentiation in COVID-19 patients, and TLR-4 is the potential target through which miR-4485 acts, providing a promising target for pro-fracture-healing and anti-osteoporosis therapy in COVID-19 patients.     

Reclamation of abandoned saline-alkali soil increased soil microbial diversity and degradation potential

Plant and Soil - Reclamation of saline-alkali soils to grow cotton (Gossypium spp.) is very common in the arid Manas River Basin in Northwest China. However, little is known about the degradation...     

Individual variation in buffalo somatic cell cloning efficiency is related to glycolytic metabolism

Science China Life Sciences - Mammalian individuals differ in their somatic cell cloning efficiency, but the mechanisms leading to this variation is poorly understood. Here we found that high...