壳聚糖抑制植物病害的研究进展

壳聚糖是一种用途十分广泛的具有生物活性的高分子化合物,本文论述了壳聚糖在抑制作物病害方面的作用。壳聚糖和为土壤改良防治土传病害、用作种衣制防治种传丰、用于果蔬保鲜控制收获后病害,还可作为植物生长调节剂、病害剂促进植物生长、诱导提高植物的广谱抗生。壳聚糖抑制植物病害具有多重机制。文章对壳聚糖等甲壳糖素衍生物在农业上的应用剪影进行了讨论。     

硫脲壳聚糖Zn(Ⅱ)配合物的制备、表征及生物活性

利用FT-IR、UV、TG-DTA和XRD手段,对合成的硫脲壳聚糖及硫脲壳聚糖-Zn(Ⅱ)配合物进行了表征,研究了壳聚糖、硫脲壳聚糖及硫脲壳聚糖-Zn(Ⅱ)配合物对细菌大肠杆菌、金黄色葡萄球菌和真菌黑曲霉的抑菌性能.结果表明:合成的硫脲壳聚糖-Zn(Ⅱ)配合物对大肠杆菌、金黄色葡萄球菌的抑菌性能比单一的壳聚糖、硫脲壳聚糖显著提高,对真菌黑曲霉亦具有较强的抑制作用.     

高活性壳聚糖的制备及特性

壳聚糖经100kGy60Coγ-射线辐射处理后,在0.01g/L的浓度下,对金黄色葡萄球菌生长抑制作用增强100倍.辐照剂量增加或减少,壳聚糖的抑菌活性均随之大幅降低.经辐射处理后形成的壳聚糖片段分子量小于10万,对金黄色葡萄球菌无明显抑制作用.     

蚯蚓养殖及蚓粪对植物土传病害抑制作用的研究进展

利用蚯蚓养殖对有机废弃物进行资源化处理是一项古老而新兴的生物技术,20世纪70年代又获得了新进展．本文从蚯蚓养殖方法、蚓粪的理化性质、蚓粪的综合利用等方面进行了综述,并着重分析了蚓粪对土传植物病害的抑制作用及其抑制机理．蚓粪对土传植物病害的抑制是蚓粪应用的另一个重要新途径,虽然只是初步研究,但已表现出明显的应用潜力。植物土传病害抑制作用与蚓粪中丰富的微生物区系有很大的关系,尤其大量拮抗微生物的存在是蚓粪具有抑病作用的重要机制．     

低聚壳聚糖美拉德衍生物抑菌性能研究

本文研究了基于与葡萄糖、麦芽糖和木糖进行美拉德反应的低聚壳聚糖衍生物的抑菌性.测定低聚壳聚糖及其衍生物对大肠杆菌和金黄色葡萄球菌的抑制效果.结果显示:壳聚糖及其衍生物对金黄色葡萄球菌的抑制作用强于对大肠杆菌的抑制作用,且随着浓度增加,对两种菌的抑菌效果增强.大多数壳聚糖衍生物的抑菌效果优于壳聚糖本身,其中CG 1∶1 8 h(低聚壳聚糖的氨基与葡萄糖的羰基的物质量比为1∶1,反应8h)的抑菌效果最好,CM 1∶3 8 h(低聚壳聚糖的氨基与麦芽糖的羰基的物质量比为1∶3,反应8 h)抑菌性最差,这可能与参加反应的还原糖种类、反应物比例以及反应时间相关.     

壳聚糖对几种植物病原真菌的作用

在马铃薯葡萄糖琼脂 ( PDA)上测定了酸溶性壳聚糖 ( S- )和 2种水溶性壳聚糖 ( S- 和 S- )对 15种植物病原真菌的作用 ,结果表明 ,三种壳聚糖对供试的 15种植物病原真菌均有一定程度的抑制作用 ,抑制强度因壳聚糖的理化性质以及不同的病原真菌而有较大差异。水溶性壳聚糖 S- 可明显抑制水稻恶苗病菌分生孢子的萌发。壳聚糖的抑菌作用机制与其增加菌丝细胞膜的透性有关。     

壳聚糖中胺基对其抑菌性能的影响及与DNA的作用

采用抑菌圈法研究了壳聚糖对大肠杆菌(E.coli)和金黄色葡萄球菌(St.aureus)的抑菌活性。利用壳聚糖的席夫碱反应,对壳聚糖的胺基进行保护后,研究了壳聚糖中胺基对其抑菌性能的影响。同时,运用紫外吸收光谱和电化学的方法,研究了壳聚糖与DNA的相互作用,提出了壳聚糖对E.coli和St.aureus的抑菌机理。研究结果表明,壳聚糖对E.coli和St.aureus具有很好的抑制作用,且抑菌活性与其胺基有关;壳聚糖能与细胞内带负电的核酸结合,使细胞正常DNA复制生理功能受到影响,抑制细菌的繁殖,从而达到抑菌的目的。     

壳聚糖体外抗白念珠菌生物膜作用的初步研究

目的观察壳聚糖对白念珠菌生物膜形成的影响,探讨其可能的作用机制。方法 XTT减低法评价壳聚糖对白念珠菌生物膜形成及黏附的影响,镜下观察壳聚糖对白念珠菌生物膜形态的影响;实时定量RT-PCR法观察壳聚糖对白念珠菌的Ras信号通路因子CDC35、PDE2、EFG1和HWP1的基因表达的影响。结果低浓度(0.02 mg/mL)和高浓度(0.32mg/mL)壳聚糖对白念珠菌生物膜形成的抑制率分别为(19.6±1.2)%和(96.96±0.6)%,0.16 mg/mL浓度下壳聚糖对早期(0 h)、中期(12 h)和成熟期(48 h)的生物膜抑制率分别为(78.6±0.5)%、(54.4±0.9)%和(41.1±1.1)%,不同浓度的壳聚糖对各黏附阶段的白念珠菌细胞黏附均有抑制作用,壳聚糖可剂量依赖性地下调白念珠菌生物膜Ras信号通路基因CDC35、EFG1和HWP1的表达水平,上调Ras信号通路抑制剂PDE2的基因表达水平(P<0.05)。结论壳聚糖可能通过影响Ras信号通路及抑制细胞黏附而对白念珠菌生物膜的形成具有抑制作用。     

壳聚糖对五种食物中毒菌生长的影响

本文报道了在pH5.5和pH6.5条件下,不同浓度的壳聚糖对五种主要的食物中毒菌:大肠杆菌、金黄色葡萄球菌、鼠伤寒沙门氏菌、李斯特单核细胞增生菌和小肠结肠炎耶尔森氏菌生长的影响。结果表明:在这两种pH条件下,壳聚糖对五种细菌有不同程度的抑制作用,而且在pH5.5比在pH6.5的条件下抑制作用更强。     

几种天然产物的抑菌性能研究

将羧甲基壳聚糖等四种天然产物作为供试样,分别测定其对大肠杆菌、金黄色葡萄球菌、绿脓杆菌、枯草杆菌的最低抑菌浓度,结果表明,四种供试样对其均有一定的抑制作用,其中壳寡糖对大肠杆菌、金黄色葡萄球菌、枯草杆菌的抑制作用最强,羧甲基壳聚糖、壳寡糖、白芨多糖对绿脓杆菌的抑制能力差不多。再根据单体实验结果,选择羧甲基壳聚糖、壳寡糖、白芨多糖进行两两复配实验,结果表明,壳寡糖与白芨多糖的复配液对于金黄色葡萄球菌、枯草杆菌有较明显的协同增效抑菌作用。     

壳聚糖调节植物生长发育及诱发植物抗病性研究进展

综述了壳聚糖在调节植物生长发育和诱导植物抗病性方面所起的重要作用及其可能的作用机制。壳聚糖对植物氨同化关键酶具有明显的生理调节功能,可以提高植物同化NH4 的能力,有利于蛋白质的生物合成与积累,改善植物的营养品质及园艺性状;并能迅速激发植物的防卫反应,启动植物的防御系统,有效地提高植物的抗病性。同时通过壳聚糖结合蛋白的分离、纯化及其生化特性的研究为进一步确定壳聚糖的作用机制奠定了基础。     

Progress of Study on Chitosan in Regulating Plants’Growth and Eliciting Plants’Defense Responses

Important effect of chitosan on regulating plant growth , eliciting plant resistance to disease and it’s possible operating mechanism are reviewed . Chitosan shows evidence physiological effect on the key enzymes of ammonia assimilation and enhances the amination capacity in plant, which is in favor of biology synthesize and accumulation of protein . Thus , chitosan improves nutrition quality and horticulture properties of plant . Moreover , chitosan rapidly stimulates plant defense responses , then startups defensive system and elevates resistance to disease . To a further understanding of the mechanism of chitosan on plant , we have isolated and determined some biochemical properties of a chitosan-bingding protein .     

壳寡糖对辣椒种子萌发及幼苗抗氧化酶活性影响研究

壳寡糖是甲壳素的重要衍生物,具有良好的生物学活性,可调节植物生长,使农作物和水果蔬菜增产丰收,因而在农业上的应用日渐增多,在农业上的应用,包括促进种子萌发和植物生长。本文选取辣椒种子为研究对象,探讨了不同浓度壳寡糖对辣椒种子萌发的影响,研究结果表明一定浓度的壳寡糖可以促进种子萌发,以0.10mg/L浓度的壳寡糖效果最显著;不同浓度壳寡糖浸种处理能激活辣椒幼苗抗氧化酶活性。     

Chitosan permeabilizes the plasma membrane and kills cells of Neurospora crassa in an energy dependent manner

Chitosan has been reported to inhibit spore germination and mycelial growth in plant pathogens, but its mode of antifungal action is poorly understood. Following chitosan treatment, we characterized plasma membrane permeabilization, and cell death and lysis in the experimental model, Neurospora crassa. Rhodamine-labeled chitosan was used to show that chitosan is internalized by fungal cells. Cell viability stains and the calcium reporter, aequorin, were used to monitor plasma membrane permeabilization and cell death. Chitosan permeabilization of the fungal plasma membrane and its uptake into fungal cells was found to be energy dependent but not to involve endocytosis. Different cell types (conidia, germ tubes and vegetative hyphae) exhibited differential sensitivity to chitosan with ungerminated conidia being the most sensitive.     

Effects of immobilizing agents and procedures on viability of cultured celery (Apium graveolens) cells

Summary In an attempt to develop concurrent permeabilization/immobilization systems for the production of secondary plant metabolites, the effects of chitosan, alginate, carrageenan gel and carrageenan/chitosan copolymers as immobilizing agents and immobilization procedures on viability of culturedApium graveolens cells have been examined. Chitosan immobilization, ascorbic and succinic acid resulted in low viability of plant cells but use of carrageenan/chitosan copolymers enabled maintenance of viable cell lines providing the potential for concurrent immobilization/permeabilization of cells and elicitation of secondary metabolites by chitosan.     

甲壳胺影响变形链球菌粘附力的研究

目的：研究甲壳胺对变形链球菌的附着力的影响。方法：通过变链菌粘附实验和细菌平皿计数法，观察变链菌在有或无甲壳胺的培养基中的粘附和生长情况，结果：1．甲壳胺对变链菌的附着有抑制作用。2．甲壳胺能使已附着的变链菌脱落。0．5％浓度的甲壳胺作用强于0．25％。3．甲壳胺对变链菌的生长数量及形态无影响。结论：甲壳胺的防龋性是由于它减弱了变链菌的粘附力，而不是通过减少变链菌的数量来实现的。     

Chitosan as antimicrobial agent: applications and mode of action

Chitosan, a hydrophilic biopolymer industrially obtained by N-deacetylation of chitin, can be applied as an antimicrobial agent. The current review of 129 references describes the biological activity of several chitosan derivatives and the modes of action that have been postulated in the literature. It highlights the applications of chitosan as an antimicrobial agent against fungi, bacteria, and viruses and as an elicitor of plant defense mechanisms.     

Effects of concentration, degree of deacetylation and molecular weight on emulsifying properties of chitosan

Chitosan has excellent emulsifying properties. Emulsifying activity and stability of chitosan were determined by integrated light scattering technique and turbidimetric method. The effects of concentration, degree of deacetylation and molecular weight on emulsifying properties of chitosan were systematically studied in the paper. Emulsifying activity of chitosan initially increased, arrived at the peak at 0.75% and then declined, while emulsifying stability continuously increased with a rise of chitosan concentration from 0.25% to 1.25%. Emulsifying activity and stability of chitosan initially decreased and reached the minimum, then increased with the rise of degree of deacetylation. Chitosan with DD 60.5% and 86.1% showed superior emulsifying activity and stability. Chitosan with low Mw exhibited better emulsifying activity than those with high Mw. Chitosan with Mw 410 kDa and 600 kDa showed superior emulsifying activity in the test range. Emulsifying stability of chitosan increased with a rise of Mw.     

饲料中添加壳聚糖季铵盐对凡纳滨对虾生长及非特异免疫的影响

实验研究壳聚糖季铵盐对凡纳滨对虾生长性能及非特异性免疫能力的影响。在饲料中分别添加0、0.05%、0.10%、0.15%和0.20%的壳聚糖季铵盐, 制成5组等氮等能饲料。将900尾[初体质量(3.820.34) g]健康的凡纳滨对虾随机分成5组(45尾4平行), 养殖时间56d。结果表明:饲料中添加壳聚糖季铵盐显著影响凡纳滨对虾的生长, 0.15%实验组凡纳滨对虾的增重率和特定生长率最佳(P0.05)。饲料中添加壳聚糖季铵盐0.1%、0.15%和0.20%能显著提高凡纳滨对虾血清溶菌酶和碱性磷酸酶及酚氧化酶的活性(P0.05)。饲料中添加壳聚糖季铵盐可显著提高凡纳滨对虾抗副溶血弧菌感染的能力(P0.05), 0.15%组的保护效果最好, 其相对免疫保护率为33.24%。壳聚糖季铵盐能显著提高凡纳滨对虾的生长性能和抗病能力, 本实验条件下适宜的添加量为0.15%。     

Chitosan-induced defence responses in tomato plants against early blight disease caused by Alternaria solani (Ellis and Martin) Sorauer

The in vitro antifungal properties of chitosan and its role in protection of tomato from early blight disease were evaluated. Chitosan inhibited the radial and submerged growth of Alternaria solani at 1?mg/ml and control tomato plants from blight pathogen. Chitosan was able to induce the level of chitinase activity and new isoforms of chitinase, resulting in the reduction of early blight disease severity in tomato leaves. These results suggested the role of chitosan in activation of defence responses as well as protecting tomato plants from A. solani infection.