植物源血管紧张素转换酶抑制剂的研究进展

血管紧张素转换酶抑制剂(Angiotensin converting enzyme inhibitors,ACEI)通过肾素-血管紧张素系统(RAS)和激肽释放酶-肽酶系统(KKS),抑制血管紧张素II的生成,减少缓激肽的降解,从而达到降血压的目的;植物来源的天然化合物具有来源广泛、结构多样、特异性高、毒性低等特点,因而从植物中筛选安全有效的ACEI成为研究热点。在此综述了血管紧张素转换酶(ACE)的活性测定方法以及植物来源的不同结构类型的ACEI研究进展。     

重金属铊胁迫下水稻(Oryza sativa L.)根系草酸含量与铊吸收的关系

铊(Tl)作为一种非必需、高毒性重金属元素,会干扰植物的正常发育,并在食物链中引起严重的毒性积累.根系分泌有机酸在抗重金属污染中起着重要作用.为研究铊胁迫下的植物根系有机酸分泌特征与重金属吸收的关系,利用水培法对T胁迫下水稻(Oryza sativa L.)植株草酸分泌和Tl分布特征进行检测和分析,研究不同抑制剂对水稻...     

DMPP mitigates N2O and NO productions by inhibiting ammonia-oxidizing bacteria in an intensified vegetable field under different temperature and moisture regimes

Vegetable soils with high nitrogen input are major sources of nitrous oxide (N₂O) and nitric oxide (NO), and incorporation of the nitrification inhibitor 3, 4-dimethylpyrazole phosphate (DMPP) into soils has been documented to effectively reduce emissions. However, the efficiency of DMPP in terms of soil N₂O and NO mitigations varies greatly depending on soil temperature and moisture levels. Thus, further evaluations of DMPP efficiency in diverse environments are required to encourage widespread application. A laboratory incubation study (28 d) was established to investigate the interactive effects of DMPP, temperature (15, 25, and 35 ℃), and soil moisture (55% and 80% of water-holding capacity (WHC)) on net nitrification rate, N₂O and NO productions, and gene abundances of nitrifiers and denitrifiers in an intensive vegetable soil. Results showed that incubating soil with 1% DMPP led to partial inhibition of the net nitrification rate and N₂O and NO productions, and the reduction percentage of N₂O production was higher than that of NO production (69.3% vs. 38.2%) regardless of temperature and soil moisture conditions. The increased temperatures promoted the net nitrification rate but decreased soil N₂O and NO productions. Soil moisture influenced NO production more than N₂O production, decreasing with the increased moisture level (80%). The inhibitory effect of DMPP on cumulative N₂O and NO productions decreased with increased temperatures at 55% WHC. Conversely, the inhibitory effect of DMPP on cumulative N₂O production increased with increased temperatures at 80% WHC. Based on the correlation analyses and automatic linear modeling, the mitigation of both N₂O and NO productions from the soil induced by DMPP was attributed to the decreases in ammonia-oxidizing bacteria (AOB) amoA gene abundance and NO^-₂-N concentration. Overall, our study indicated that DMPP reduced both N₂O and NO productions by regulating the associated AOB amoA gene abundance and NO^-₂-N concentration. These findings improve our insights regarding the implications of DMPP for N₂O and NO mitigations in vegetable soils under various climate scenarios.     

Effects of pirenzepine on expression of MMP-2 and TIMP-2 in stroma of sclera in chick myopic eyes

AIM:To observe the effect of intravitreal injection of pirenzepine on form-deprivation myopia in chicks. METHODS:Forty-one day old chicks were randomly divided into 4 groups:normal control group, form deprivation group, vehicle control group and pirenzepine injection group. The right eyes of all chicks were used as experimental eyes. The deprived eyes in vehicle control group and pirenzepine injection group received daily intravitreal injection of vehicle control solution(0.01 mol/L PBS) and pirenzepine(1%in PBS), respectively. Optical examinations such as refraction, axial length and equatorial diameter were made at the end of the 5th day. The mRNA and protein levels of matrix metalloproteinase 2(MMP-2) and tissue inhibitor of metalloproteinase-2(TIMP-2), and the activity of MMP-2 were detected by RT-PCR, Western blotting and zymography analysis,respectively. RESULTS:Refraction, axial length and equatorial diameter of the eyes in pirenzepine injection group were significantly lower than those in form deprivation group and vehicle control group(P<0.05), but those were higher(P<0.05) and the eyes were relatively myopic as compared with normal control group. The mRNA expression, protein le vels and activity of MMP-2 in pirenzepine group were significantly higher than those in normal control group(P<0.01), and were significantly lower than those in form deprivation group and vehicle control group(P<0.01, P<0.01). The mRNA and protein levels of TIMP-2 in pirenzepine group were significantly lower than those in normal control group(P<0.01), and was significantly higher than those in form deprivation group and vehicle control group(P<0.01, P<0.01). CONCLUSION:Intravitreal injection of pirenzepine may partly prevent form-deprivation myopia by modulating the expression of MMP-2 and TIMP-2 in the fibrous layer of sclera.     

Influence of moisture regime on inhibition of nitrification by DCD

A laboratory study at the Indian Agricultural Research Institute, New Delhi showed that DCD was an efficient nitrification inhibitor under field capacity moisture (???30 kPa) but not so under submerged soil conditions. Nitrification inhibition by DCD was 79.6% after 1 week of incubation and decreased to 59.3% after 3 weeks of incubation under field capacity moisture, while it was only 19.3% after 1 week of incubation and 10.6% and 18.4% after 2 and 3 weeks of incubation under submergence, respectively. DCD can play an important role in reducing N losses from agricultural fields.     

原卟啉原氧化酶抑制剂类除草剂进展概况

本文对近期开发的原卟啉氧化酶抑制剂按用途进行了简要的介绍。文中涉及原卟啉氧化酶抑制剂的化学结构、生物活性、登记与专利和开发公司等。     

反刍动物甲烷生成量的调控

反刍动物体内甲烷的产生是瘤胃发酵能损失的主要原因,减少甲烷产量对提高反刍动物的能量利用率和环境保护均具有重要意义。因此,本文就反刍动物甲烷生成的机制及影响其生成量的因素等方面做一综述,并对降低甲烷生成量的调控方式进行了分析和展望。     

细菌耐药颉颃剂的研究现状及应用

作者介绍了具有颉颃细菌耐药性作用的物质的研究应用进展情况，包括灭活酶抑制剂、药物渗透促进剂、外输泵抑制剂、细菌生物被膜抑制剂、抗菌药物增强剂、耐药质粒消除剂等。     

Caspase 3 inhibitor Ac-DEVD-CHO attenuates 10-hydroxycamptothecin-induced activation of NF-κB in Bcap37 cells

AIM:To investigate the role of caspase 3 inhibitor Ac-DEVD-CHO in caspase 3 signaling pathway and NF-κB activation induced by 10-hydroxycamptothecin (HCPT) in human breast carcinoma cells. METHODS:The cell growth inhibition was measured by MTT assay. Agarose gel electrophoresis was performed for detecting cell apoptosis. Western blotting was used for determining protein expression. DIG-EMSA was conducted to measure the DNA-binding activation of NF-κB. RESULTS:Caspase 3 inhibitor Ac-DEVD-CHO attenuated HCPT-induced apoptosis in human breast carcinoma. Ac-DEVD-CHO also suppressed the degradation of caspase 3 and IκBα,and arrested the activation of NF-κB. CONCLUSION:Caspase 3 inhibitor Ac-DEVD-CHO regulates the activation of caspase 3 and NF-κB,and attenuates apoptosis in Bcap37 cell line induced by HCPT.