Ca^(2+)信号途径参与稻瘟病菌分生孢子萌发及附着胞形成的调控

为了确定Ca2+信号途径是否参与、在哪一时期参与稻瘟病菌分生孢子萌发及附着胞形成过程的调控,用四种可从不同位点阻断Ca2+信号途径的抑制剂分别处理分生孢子,观察抑制剂对孢子萌发及附着胞形成过程的抑制作用。结果表明:Ca2+螯合剂EGTA、Ca2+通道抑制剂Verapamil、抑制磷脂酶C活性的抑制剂U-73122、影响钙调素与钙调素依赖蛋白激酶作用位点的抑制剂KN-93,随着浓度的增加,对孢子萌发和附着胞形成过程的抑制作用明显增强;同一浓度下,抑制剂对附着胞形成过程的抑制作用大于孢子萌发过程;抑制剂影响孢子萌发和附着胞形成过程在萌发早期(1~4h)最有效;在完全被抑制、不能萌发的孢子内出现了许多颗粒状囊泡;抑制剂可使附着胞形态明显变小甚至不能形成。以上结果表明钙信号途径参与了稻瘟病菌孢子萌发及疏水条件下附着胞形成过程的调控。

钙信号途径参与小斑病菌致病过程的调控

为确定Ca2+信号途径与玉米小斑病菌致病过程的相关性,用可从不同位点阻断Ca2+信号转导途径的抑制剂分别处理小斑病菌的分生孢子,结果表明:Ca2+螯合剂EGTA、Ca2+通道抑制剂Verapam il、影响钙调素与钙调素依赖蛋白激酶作用位点的抑制剂KN-93,随着浓度的增加,对孢子萌发和附着胞形成过程的抑制作用明显增强;同一浓度下,抑制剂对附着胞形成过程的抑制作用大于孢子萌发过程;抑制剂可使附着胞形态明显变小甚至不能形成。以上结果表明钙信号途径参与了玉米小斑病菌主要致病过程的调控。

球虫消毒剂的筛选及氨水对艾美耳球虫卵囊抑杀条件的优化

为了筛选有效的球虫消毒剂,本研究将柔嫩艾美耳球虫卵囊分别与16种常用消毒剂和1种高效抗球虫药物溶液(250mg/L妥曲珠利溶液)混合作用2h然后在2.5%重铬酸钾溶液中孢子化培养,或混合作用4h后接种14日龄雏鸡,根据卵囊孢子化率、孢子化抑制率、每克粪便卵囊数量(oocysts per gram of feces,OPG)、病变计分和血便情况评价消毒剂和抗球虫药物抑杀球虫卵囊效果。结果显示,8%氨水对未孢子化卵囊和孢子化卵囊均表现为100%的抑杀效果;250mg/L妥曲珠利、3%甲醛、4%苯酚、0.5%过氧乙酸、5%NaOH+10%NaCl和5%NaOH对球虫卵囊活性具有一定的抑制作用,孢子化抑制率超过10%,但是对孢子化卵囊抑杀作用不明显;而剩余10种常用消毒剂对球虫卵囊没有明显的抑杀作用。氨水抑杀球虫卵囊条件优化的试验结果显示,1%～8%氨水与未孢子化卵囊作用1h以上,均可100%抑杀球虫卵囊活性。粪便干扰试验结果显示,粪便不影响2%和4%氨水对球虫卵囊的抑杀效果。本研究结果说明常用消毒剂和抗球虫药物不能有效杀灭球虫卵囊的活性,而氨水是一种高效球虫消毒剂。本研究结果可为开发新型高效球虫消毒剂和球虫病控制提供参考。

西芹鲜根丙酮浸提物层析流分对黄瓜枯萎病菌的化感作用以及化感物质鉴定

为探明西芹鲜根中化感物质成分,利用柱层析法对西芹鲜根丙酮浸提液进行4次层析,每次层析后获得的流分与黄瓜枯萎病菌共培养,测定菌落直径与孢子萌发率,以化感抑制效果筛选最佳流分,然后通过GC-MS对第4次层析最佳流分中化感物质进行鉴定。结果表明,各次层析最佳流分均对黄瓜枯萎病菌菌丝生长及孢子萌发有较强抑制作用,第4次层析获得的最佳流分(RA3246、RA3344、RA9889、RA91064)对枯萎病菌菌丝生长的化感抑制效果[相对于第4次层析丙酮对照(ACK4)]分别升高至28.69%、37.83%、42.44%、33.83%,孢子萌发抑制率分别升高至50.72%、50.66%、55.02%、59.37%。通过GC-MS共鉴定出有机酸、酚、醇、酯类、杂环有机物及含氮化合物6类12种化感物质,分别为3-羟基扁桃酸、硫代乙醇酸、2,4-二叔丁基苯酚、十二烷醇、2-甲基-2-丙烯酸十三烷酯、2-丙烯酸十二烷基酯、2-丙稀酸十五烷基酯、二甲基环己酯、3,4-环氧呋喃、十六烷基二甲基叔胺、(Z)-9-十八烯酸酰胺和二丁氨腈。研究获得结果可为利用西芹提取物防控黄瓜枯萎病提供理论基础。

辣椒枯萎病拮抗细菌Ljb002菌株发酵条件的优化

从辣椒根际分离筛选到1株具有较强促生能力但拮抗能力一般的细菌菌株Ljb002,为提高抑制辣椒枯萎病病原菌孢子的萌发能力,采用响应面分析方法(Response Surface Methodology,RSM)对该菌株的液体发酵条件进行优化。在单因素的基础上利用Plackett-Burman设计方法对8种影响因素进行了重要性评价。结果表明,初始p H、蛋白胨和Mg SO_4加入量对菌株Ljb002发酵液抑制孢子萌发的能力有显著影响。采用响应面分析方法对这3个主要因素进行优化,优化的最佳条件组成为初始pH 7.72、蛋白胨12.93 g/L、硫酸镁1.98g/L、葡萄糖20 g/L、接种量3%、种龄10 h、100 m L三角瓶装液量为14 m L、培养温度28℃,此时相对孢子萌发抑制率最大为96.73%。在验证试验中相对孢子萌发抑制率达到了95.18%,与优化前相对孢子萌发抑制率64.37%相比提高了32.37%。

三种杀菌剂对木霉菌及食用菌的毒力测定

测定了 3种杀菌剂对木霉菌和食用菌的抑制作用 .结果表明 ,施保克、施保功对木霉菌的孢子萌发和菌丝生长均有极强烈的抑制作用 ,其 EC50 分别是施保克为 0 .74和 0 .6 8mg· L-1;施保功为 0 .6 9和 0 .89mg·L-1;多菌灵仅对木霉菌丝有抑制作用 ,EC50 为 114.77mg· L-1,对木霉孢子萌发无抑制作用 .施保克、施保功、多菌灵对香菇菌丝的 EC50 分别为 13.4 0、13.78和 32 4 .0 mg· L-1,对茶薪菇的 EC50 分别为 14.93、10 .71和2 2 9.50 mg· L-1.

64种植物提取物的离体抗真菌活性评价

测定了64种植物的甲醇提取物对荔枝霜疫霉菌(Peronophythora litchii Chen ex Ko et al.)和香蕉炭疽病菌(Colletotrichummusae(Berk.et Curt.)Arx)的离体抗菌活性。试验结果显示,在提取物质量浓度为0.01g/mL 时,对荔枝霜疫霉菌菌丝生长的抑制率高于50%的植物共有30种.对霜疫霉菌孢子囊萌发的抑制率高于50%的植物共有26种;对香蕉炭疽病菌菌丝生长的抑抑制率高于50%的植物共有18种,对香蕉炭疽病孢子萌发的抑制率高于50%的植物共有6种;对两种病原菌的菌丝生长与孢子萌发抑制率均大于50%的植物有开口箭(Tupistra chinensis Bak.)和苍耳(Xanthinum sibiricum Patrin)。

一株多粘类芽胞杆菌防治油茶炭疽病初探

多粘类芽胞杆菌是一种能防治多种病原真菌病害的生防细菌。通过室内孢子萌发抑制率、抑菌率测定、林间防治试验首次研究不同芽胞浓度的多粘类芽胞杆菌Paenibacillus polymyxa DN-1对油茶炭疽病的防治效果。结果表明,当终浓度在（10～160）亿芽胞/L（667 m^2用水量50 L）时,对4株油茶炭疽病病原菌Colletotrichum gloeosporioides Penz.孢子萌发抑制率41.50%～88.75%;抑菌率35.81%～77.56%;在汤池镇和舒茶镇两地,发病初期施药后30 d林间防效为29.80%～68.91%和31.11%～67.55%;发病高峰期施药后30 d林间防效为26.61%～50.20%和21.95%～52.66%;DN-1终浓度160亿芽胞/L时,在发病初期施药两地林间防治效果与百菌清相当;而在发病高峰期施药林间防治效果低于百菌清。

10种植物源提取物对3种植物病原菌的抑菌活性研究

以槟榔叶斑病菌(Pestalotiopsis microspora)、椰子泻血病菌(Ceratosystis paradoxa)和花生焦斑病菌(Leptosphaerulina crassiasca)3种植物病原真菌为供试菌,对10种植物提取物的抑菌活性进行了测定。结果表明:在供试浓度为0.025g/mL时,飞机草对3种供试病原菌生长抑制效果最好,抑制率均为100%;其次是菠萝蜜,对椰子泻血病菌、花生焦斑病菌和槟榔叶斑病菌3种病原菌的抑制率分别为100%、92.2%和90.7%;三角梅对椰子泻血病菌的抑制率为91.1%,但是对其他两种的抑制效果均低于80%;芭蕉、假臭草的抑制率都在80%以上。在浓度为0.05g/mL时,飞机草对3种病原菌孢子的抑制作用明显,都在80%以上;菠萝蜜对其中两种病原菌椰子泻血病菌、花生焦斑病菌的孢子萌发抑制率为80%以上;三角梅对椰子泻血病菌的孢子萌发抑制率为80%以上;假臭草和芭蕉提取物对3种病原菌的孢子萌发抑制率相对较低。

Inhibition of Chlamydospore Germination and Mycelial Growth of Trichoderma spp. by Chemical Fungicides

For exploring the influences of application and residue of chemical fungi- cides on chlamydospore preparations of Trichoderma spp., the effects of seven chemical fungicides on chlamydospore germination and mycelia growth of two bio- control fungi T. harzianum 610 and T. Iongibrachiatum 758 were studied. Carben- dazim, tebuconazole and difenoconazole showed strong toxicities, thiram and car- bexin showed moderate toxicities, and metalaxyl showed Mycelia growth of the two strains was more sensitive to most tested fungicides than those of chlamydospore germination. Chlamydospore germination of 610 was more sensitive to tested fungicides than those of 758, and mycelia growth of 758 was more sensitive to most tested fungi- cides than those of 610. Among the seven fungicides, 98% carbendazim had the strongest effects （ECru values were 1.64 and 0.05μpg/ml）, and 70% pentachloroni- trobenzene had the weakest effects （EC50 values were 1.64 and 0,05 μg/ml） for chlamydospore germination and mycelia growth of 610. As for 758, 98% carbendaz- im had the strongest inhibitory effects and 95% metalaxyl had the weakest inhibitory for chlamydospore germination of 756 （EC50 values were 0.62 and 1 108.61 μg/ml respectively）, whereas 96.2% tebuconazole showed the strongest inhibitory effects for mycelia growth of 758 （EC= value was 0.32μg/ml）, and 95% metalaxyl was the weakest （EC= value was 1 206.29 μg/ml）. According to the applied concentration of different fungicides in practice, we concluded that chlamydospore preparations of 610 and 758 could not be combined with carbendazim, tebuconazole, thiram and carboxin for controlling plant diseases, and the pesticide residues to the biocontrol effects should be kept in mind. Chlamydospore preparations of 610 and 758 can be and difenoconazole for controlling plant dis- eases, 758 chlamydospore preparations and germinated chlamydospore of 610 can be combined with metalaxyl for controlling plant diseases, and pesticide residue risk was not serious.

湖南农科院研制成功防治水稻稻曲病的生防杀菌剂

近日，从湖南省农科院植保所传出喜讯，植保专家成功研制出用于防治水稻稻曲病的生防杀菌剂PSB-10。据了解，这是一种高效防控水稻稻曲病的生物制剂，成为“综合防控技术体系”的核心技术，尤其对稻曲病孢子萌发抑制率达100％。试验表明该药剂对稻曲病平均防效达76．32％，不仅比对照增产5．12％，而且无毒副作用。

哈茨木霉菌毒素与世高对桑葚核地杖菌抑菌活性的生物测定

核地杖菌(Scleromitrula shiraiana)是桑葚白果病的主要病原菌之一,为害桑葚引起"白果病"。本文研究了哈茨木霉菌与世高单剂及混合物防治核地杖菌的潜力。研究结果表明:哈茨木霉的乙醇提取物(毒素)对核地杖菌菌丝生长和孢子萌发的抑制率分别为70%和80%以上,在室内条件下哈茨木霉毒素与世高对核地杖菌菌丝生长抑制的EC_(50)分别为5.97、19.73μg/mL。哈茨木霉与世高混合物对核地杖菌的抑制效果与混合物中两种单剂的含量有关,混合物T3(3.0+7.0),T5(6.0+7.0)和T6(6.0+14.0)处理组对核地杖菌的抑制效果表现为增效作用;从对病原菌的抑制效果、使用成本与化学农药使用量等方面考虑,混合物T5是用于防治核地杖菌的最佳组合。本研究结果可为使用哈茨木霉毒素及其与世高联合防治桑葚白果病提供参考。

Enhancement of CD4^+ T cell activities and modulation of Th1/Th2 lineage development in radiated tumor-bearing rats treated with male zooid of Antheraea pernyi extracts

AIM： To investigate whether supplementation of male zooid of Antheraea pernyi extracts （MZAPE） could enhance immune function of radiated tumor-bearing rats. METHODS： Eighty male Wistar rats were randomly divided into a control group, a simple radiation group, a MZAPE group, and a radiation plus MZAPE group. With the tumor model established by implanting Walker-256 ascites tumor cells, tumor weight and tumor control rate were calculated. The rats in the simple radiation and radiation plus MZAPE groups were underwent to radiation at 10 Gy within 2 d. In the MZAPE and radiation plus MZAPE groups, the MZAPE was gavaged at a dose of 16.53 mg/kg once a day for 7 d. T cell subsets in peripheral blood were determined by flow cytometry and the expression of IL-2, IFN-γ, IL-4 and IL-10 in sera were determined by ELISA on the 8th d. RESULTS： The tumor weight of simple radiation group, MZAPE group and radiation plus MZAPE group was lower than that of control group （P 〈 0.01） and tumor control rates were 63.08% ± 6.43%, 69.86%± 7.12% and 35.30% ± 7.67%, respectively. CD^4＋ T and CD^8＋ T cells in the peripheral blood of the simple radiation group were fewer than in control group. In the MZAPE and radiation plus MZAPE groups, the number of CD^4＋ T cells was higher while CD^8＋ T cells was lower than in the control and simple radiation groups. Expression of IL-2 and INF-y in the radiation group was lower than in control group, and significantly enhanced during MZAPE therapy （P 〈 0.05）. Expression of IL-4 and IL-10 in the radiation group had no significant changes compared with the control group, and decreased significantly after MZAPE treatment （P 〈 0.01）. CONCLUSION： MZAPE administration may help improve the immune function of the radiated tumor-bearing rats and reverse the radiation-induced immune inhibition by promoting the proliferation of T helper cells and inducing the transdifferentiation from Th2 to Th1.

柠檬苦素通过破坏根霉细胞壁和细胞膜的完整性起抑菌作用

据《食品工业科技》2019年第8期《柠檬皮中柠檬苦素对根霉的抑菌活性和机理》(作者王辉等)报道,通过测定柠檬皮中柠檬苦素对根霉的最小抑菌浓度(MIC)、最小杀菌浓度(MBC)、孢子萌发抑制率、菌丝萌发抑制率确定其抑菌活性,根据测定各因素对抑菌活性的影响确定抑菌活性的稳定性;并通过扫描电镜观察和测定根霉细胞外碱性磷酸酶(AKP)含量和蛋白质含量、菌丝体的总糖含量,分析柠檬皮中柠檬苦素对根霉的抑菌机理。

植保专家成功研制出用于防治水稻稻曲病的生防杀菌剂PSB-10

近日．从湖南省农科院植保所传出喜讯。植保专家成功研制出用于防治水稻稻曲病的生防杀菌剂PSB-10。据了解．这是一种高效防控水稻稻曲病的生物制剂．成为“综合防控技术体系”的核心技术．尤其对稻曲病孢子萌发抑制率达100％。试验表明．该药剂对稻曲病的平均防效达76．32％，不仅比对照增产5．12%．而且无毒副作用。

Evaluation of the Appropriateness of Gastrointestinal Prophylaxis in the Critically III

The aim of this study was to determine the utilization of SRMD （stress related mucosal disease） prophylaxis in the ICU （intensive care unit） of a large teaching institution based on duration and defined adverse effects. Patients were reviewed for appropriateness of SRMD prophylactic therapy based on the presence of two independent risk factors （coagulopathy and mechanical ventilation greater than 48 hours） versus presence of any one risk factor from a list developed by the study investigator. Data was collected into spreadsheets and outcomes were analyzed using descriptive statistics. When evaluating patients based on the presence of any risk factor, 84 percent of patients had at least one risk factor present, while 16 percent did not have any. In patients who received famotidine, there was one occtLrrence of Clostridium difficile and 6 cases of electrolyte abnormalities. In patients who received a PPI, there was one documented case of HAP, two cases of ventilator-associated pneumonia, three cases of Clostridium difficile, and 14 patients who developed electrolyte abnormalities. Data does not show an association between acid suppression therapy and incidence of nosocomial infections. The number of patients whose therapy exceeded the appropriate stop-date compared with the number of patients in which SRMD prophylaxis was discontinued when risk factors diminished was greater when evaluating patients based upon the two independent risk factors.

高原土壤中稻瘟病拮抗细菌的抑菌效果及抗菌机理

利用平板稀释法从西藏7个不同地点的土壤中分离筛选细菌,并通过平板对峙法对所分离菌株的稻瘟病菌抑制效果进行初筛,获得一株拮抗细菌YN01,对其进行生理生化和分子生物学鉴定、最适生长和发酵条件筛选,分泌IAA和铁载体能力检测及稻瘟病菌孢子抑制实验.经形态、生理生化特征和分子生物学鉴定,确定菌株YN01为萎缩芽孢杆菌(Bacillus atrophaeus).YN01对稻瘟病菌丝生长的抑制率超过90%,最适生长碳源、氮源分别为蔗糖和酵母粉,在pH值低于6时不能正常生长,最适生长温度为30-35℃;碳源及氮源分别为乳糖和谷氨酸、pH值为8以及培养温度为30-35℃时发酵液抑菌活性最强;YN01能够分泌IAA,浓度达到4.287 mg/L,同时能够产生铁载体,可溶性指数为1.72;与阴性对照相比,菌悬液和发酵液对稻瘟病菌的孢子萌发起到显著的抑制效果.拮抗菌菌体通过与病原菌丝进行营养和空间位点竞争以及产生有抑菌效应的代谢产物,从而导致稻瘟病菌的孢子萌发缓慢,菌丝发育停滞,扰乱其生理活动,达到抑菌目的.综上,拮抗细菌YN01具有较强的抑菌活性,是潜在的植物病原真菌生防菌资源,具有一定的开发与应用价值.

Construction and analysis of the c DNA subtraction library of yeast and mycelial phases of Sporothrix globosa isolated in China: identification of differentially expressed genes

Species included in the Sporothrix schenckii complex are temperature-dependent with dimorphic growth and cause sporotrichosis that is characterized by chronic and fatal lymphocutaneous lesions. The putative species included in the Sporothrix complex are S. brasiliensis, S. globosa, S. mexicana, S. pallida, S. schenckii, and S. lurei. S. globosa is the causal agent of sporotrichosis in China, and its pathogenicity appears to be closely related to the di- morphic transition, i.e. from the mycelial to the yeast phase, it adapts to changing environmental conditions. To determine the molecular mechanisms of the switching process that mediates the dimorphic transition of S. globosa, suppression subtractive hybridization （SSH） was used to prepare a complementary DNA （cDNA） subtraction library from the yeast and mycelial phases. Bioinformatics analysis was performed to profile the relationship between dif- ferently expressed genes and the dimorphic transition. Two genes that were expressed at higher levels by the yeast form were selected, and their differential expression levels were verified using a quantitative real-time reverse transcriptase polymerase chain reaction （qRT-PCR）. It is believed that these differently expressed genes are involved in the pathogenesis of S. globosa infection in China.