Application and mechanisms of metal-based nanoparticles in the control of bacterial and fungal crop diseases

Nanotechnology is a young branch of the discipline generated by nanomaterials. Its development has greatly contributed to technological progress and product innovation in the field of agriculture. The antimicrobial properties of nanoparticles (NPs) can be used to develop nanopesticides for plant protection. Plant diseases caused by bacterial and fungal infestations are the main types of crop diseases. Once infected, they will seriously threaten crop growth, reduce yield and quality, and affect food safety, posing a health risk to humans. We reviewed the application of metal-based nanoparticles in inhibiting plant pathogenic bacteria and fungi, and discuss the antibacterial mechanisms of metal-based nanoparticles from two aspects: the direct interaction between nanoparticles and pathogens, and the indirect effects of inducing plant resilience to disease. © 2022 Society of Chemical Industry.     

胚胎干细胞分离培养研究进展

胚胎干细胞(ESCs)是一种高度未分化,能自我复制、自我更新,在体外连续传代并保持未分化状态和具有发育全能性的细胞.文章从研究概况、体外分离培养、生物学特性、鉴定方法、影响ESCs分离培养的因素、存在问题以及应用前景等方面对胚胎干细胞进行了概述.     

花烛体细胞胚胎发生及植株再生研究

 以花烛(Anthurium andraeanum Lind. ) 盆花品种无菌苗叶片、叶柄、根段为外植体, 对花烛体细胞胚胎发生及植株再生进行了研究, 建立了花烛体细胞胚胎发生体系。结果表明, 花烛叶片较其他外植体更适宜体细胞胚的诱导; 胚性愈伤组织及胚性结构诱导最适培养基为改良MS + 2, 4-D 2.0～3.0 mg·L ^{- 1} + KT 0.5 mg·L ^{- 1} +蔗糖2% +葡萄糖1% , pH 5.5, 暗培养40 d, 诱导率可达90.3%; 体胚发育适宜培养基为改良MS + 6-BA 0.5 mg·L ^{- 1} +蔗糖3% , 光强20 μmol·m ^-2 · s^-1 , 培养20 d后体胚萌发率达6219%; 萌发的体胚在发育培养基上继续培养30 d后均能发育成完整植株。对不同阶段培养材料的组织结构及超微结构的观察证明了花烛体胚发生过程。     

Effect of Heat Shock Protein-90 (HSP-90) mRNA Expression in Intestinal Tissuse of Chickens Infected with E.necatrix

The 90 chickens were randomly divided into control group, E.necatrix one time infection group and E.necatrix two times infection group.We used duplex PCR method to test the expression changes of HSP-90 mRNA in intestinal tissue of chickens infected with E.necatrix and researched the effects of it comprehensively and systematically.The results were showed that after 0 to 14 days the expression of HSP-90 mRNA in intestinal tissues of 14-day-old chickens infected with E.necatrix presented a upward trend though it was lower than the control chickens.These chickens were infected with E.necatrix again at 28 days, HSP-90 mRNA expressions of duodenum, jejunum and ileum decreased and then increased.However, it always showed a downward trend in appendix.When 28 days chickens were infected with high-does E.necatrix once, HSP-90 mRNA expressions of duodenum, jejunum and appendix were in a declining curve.While it was increased originally and then decreased in ileum.This study indicated that HSP-90 mRNA expressions in intestinal tissue of chickens infected with E.necatrix were inhibited at first, and the expression quantity was closely related to the degrees of intestinal tissue damage.     

珠海观光农业发展对策

笔者分析了珠海发展观光农业的地理优势、自然环境和人文环境等优势，着重提出了珠海发展观光农业的对策。     

猪笼草消化液中蛋白酶的活性初探

为了进。步分析猪笼草瓶状体内消化液中蛋白质的性质，本研究在不同的温度和pH条件下测定消化液中蛋白酶的活性，并且比较了3种不同沉淀方法对消化液蛋白进行的浓缩，通过SDS-聚丙烯酰胺电泳对消化液蛋白作了初步分离。结果表明，猪笼草消化液中蛋白酶的最适酶活温度为50℃，且稳定性最高；当pH为5时，该蛋白酶活性出现峰值，采用氯仿-正丁醇法（5：1）沉淀浓缩猪笼草消化液蛋白样品效果最佳。聚丙烯酰胺电泳结果表明，消化液至少包括三种蛋白组分，分子量分别为24.3kD、35．1kD和61．4kD，且35．1kD条带具有抗胰蛋白酶消化活性。本研究为综合开发利用猪笼草野生资源提供理论依据。     

珠三角农业休闲旅游发展现状与开发建议

近年来,农业休闲旅游已成为我国旅游业发展的一个新亮点和农村经济的新增长点,需要政府和旅游行业与企业加强引导,促进其健康有序发.文章基于珠三角农业休闲旅游发展现状与开发进行探讨.     

Effect of microRNA-155 on regulation of angiogenesis in diabetic rats with cerebral ischemic injury

AIM: To evaluate the effect of microRNA-155(miRNA-155) on the regulation of angiogenesis in diabetic rats with cerebral ischemic injury. METHODS: Adult male Sprague-Dawley rats were randomly divided into 5 groups:sham group, cerebral ischemia group, diabetic cerebral ischemia group, diabetic cerebral ischemia+miRNA-155 inhibitors group and diabetic cerebral ischemia+scramble group. Diabetes model was made by injection of streptozocin and permanent cerebral ischemic model was developed by suture-occluded method. The scores of neurological deficit and infarct volume were estimated at 24 h after cerebral ischemia. miRNA-155 level was detected by real-time polymerase chain reaction. The expression of platelet endothelial cell adhesion molecule-1(PECAM-1/CD31) and vascular endothelial growth factor(VEGF) was detected by Western blotting. RESULTS: miRNA-155 inhibitor significantly reduced miRNA-155 levels in the ischemic cortex(P<0.05), improved the scores of neurological deficit, reduced infarction size and upregulated the levels of CD31 and VEGF(P<0.05). CONCLUSION: miRNA-155 has a critical role in the regulation of angiogenesis in diabetic rats with cerebral ischemia. Down-regulation of miRNA-155 using miRNA-155 inhibitor attenuates brain infarct injury in diabetic rats.     

BTOPMC/SCAU分布式流域水文模型原理和系统设计

BTOPMC(block-wise use of TOPMODEL(TOPgraphic MODEL,基于地形的水文模型)with the Muskingum-Cunge method,分块应用TOPMODEL和马斯京根-康吉汇流方法)是一个具有较强物理基础的分布式流域水文模型,主要用于教学和流域研究,模型有待软件化,以便用于流域作业预报和水资源管理。该文采用多层架构体系设计了该模型的计算机系统,形成了BTOPMC/SCAU(south china agricultural university),系统由数据层、模型层、通信层、数据表达层和用户操作层组成,运行环境采用客户端/服务端模式。提供手动和自动2种参数率定模式,自动率定采用SCE-UA(shuffled complex evolution developed at university of arizona)全局最优算法,内置7种目标函数。采用Open MP(open multi-processing,开放式多处理)多核并发编程技术在产汇流模块实现了多核并行计算。系统为流域水文作业预报和水资源管理提供了精致的方法和简便工具。