提高苏云金杆菌防治效果技术的研究

系统介绍了Bt的生理特征、杀虫机理以及在应用中存在的问题,提出了提高Bt防治效果的技术措施。     

腐殖酸水溶肥配施枯草芽孢杆菌对基质青菜生长的影响

为探究腐殖酸水溶肥、枯草芽孢杆菌对基质青菜生长的影响 本研究以抗热605青菜为试验材料,共设计6组施肥试验,分别为CK1(有机肥2.5g/盆)、CK2(有机肥2.5g/盆+枯草芽孢杆菌0.5g/盆)、T1(有机肥2.5g/盆+枯草芽孢杆菌0.5g/盆+腐殖酸水溶肥100倍液)、T2(有机肥2.5g/盆+枯草芽孢杆菌0.5g/盆+腐殖酸水溶肥200倍液)、T3(有机肥2.5g/盆+枯草芽孢杆菌0.5g/盆+腐殖酸水溶肥400倍液)、T4(有机肥2.5g/盆+枯草芽孢杆菌0.5g/盆+腐殖酸水溶肥800倍液),研究结过表明:腐殖酸水溶肥配施枯草芽孢杆菌可在一定程度上增加基质青菜的株高、叶宽、叶长、冠幅及地上鲜重,其中腐殖酸水溶肥起主导作用,枯草芽孢杆菌作用较为微弱,综合各生长指标考量以T2处理效果最佳。     

鸡蛋壳蜡样芽孢杆菌的分离鉴定及耐药性分析

【目的】 分析不同环境下鸡蛋外壳携带蜡样芽孢杆菌的情况和分离菌株的基本特征。【方法】 从养殖场和超市各采集9种新鲜鸡蛋,对鸡蛋表面携带的蜡样芽孢杆菌进行分离鉴定、基因分型、毒力基因筛查和耐药性分析。采用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）技术对分离菌株进行初步鉴定,全基因组测序后进行菌种鉴定并确定基因分型、筛选毒力基因和耐药基因,同时采用微量肉汤稀释法测定分离株对头孢曲松、红霉素、万古霉素等12种抗菌药物的耐药性。【结果】 经MALDI-TOF MS初步鉴定和基因组菌种鉴定,确定从养殖场3种未经清洁加工的鲜蛋中分离出的6个菌株为蜡样芽孢杆菌,其序列分型（ST）较为多样,其中有2株新的ST型。在毒力基因筛查方面,6株蜡样芽孢杆菌均检出了非溶血型肠毒素nheB基因、腹泻型毒力因子hlyⅡ基因和侵袭免疫系统的inhA基因;nheA和nheC基因携带率为83.3%,编码溶血型肠毒素HBL的hblA、hblC和hblD基因携带率均为66.7%;cytK和hlyⅢ基因携带率分别为33.3%和50.0%;肠毒素基因BceT、entFM和致吐毒素基因ces均未检出。耐药性方面,6株菌均对庆大霉素、四环素、氯霉素、利福平、利奈唑胺和环丙沙星敏感,对氨苄西林、头孢曲松和泰妙菌素耐药;对红霉素、克林霉素的中介率分别为83.3%和100%;33.3%的菌株对万古霉素耐药。6株菌均携带有磷霉素耐药基因FosB和万古霉素耐药基因簇vanA的部分基因vanRSYZ,其中5株菌携带大环内酯类药物耐药基因mphL,部分菌株携带β-内酰胺类药物耐药基因或核苷类药物耐药基因。【结论】 本试验从养殖场未经消毒处理的鸡蛋外壳上成功分离到了蜡样芽孢杆菌,并发现其携带有多种毒力基因,存在多重耐药性,有潜在致病性和公共安全风险。     

地衣芽孢杆菌发酵条件优化和抑菌活性测定

【目的】探究不同培养及发酵条件对地衣芽孢杆菌19148抑菌作用的影响及地衣芽孢杆菌19148的耐药性。【方法】设计单因素试验,分别在不同温度、酸碱度、金属离子、摇床转速、发酵时间和接种量的条件下培养地衣芽孢杆菌19148菌液,将培养后的菌液离心、过滤制成无菌滤液,并通过牛津杯抑菌试验探究无菌滤液对大肠杆菌K88、鼠伤寒沙门氏菌和金黄色葡萄球菌1882的抑制能力。通过药敏纸片法探究地衣芽孢杆菌19148对27种抗菌药的耐药性。【结果】地衣芽孢杆菌19148在4和75 ℃下生长受到抑制,25、37和45 ℃能正常生长,其中在37 ℃抑菌活性最好。在pH 5.0~9.0的条件下能正常生长,在pH为6.0条件下抑菌活性最好,对铜离子不耐受,但对镁离子表现出了良好的耐受性,且不同浓度镁离子处理组间抑菌活性无显著差异（P＞0.05）。体外发酵试验中,地衣芽孢杆菌19148在3%种子液接种量、150 r/min发酵28 h时,体外发酵的抑菌活性最好。耐药性评价试验结果显示,地衣芽孢杆菌19148对青霉素、四环素、头孢他啶、呋喃唑酮和多黏菌素B 5种抗菌药中介,对头孢哌酮和红霉素等其他22种抗菌药敏感。【结论】地衣芽孢杆菌19148具有较好的稳定性,能应用于工业发酵饲料生产,对抗菌药不具有耐药性。     

1株黄曲霉颉颃菌的鉴定及其抑菌活性成分分析

【目的】 筛选黄曲霉颉颃菌,探究其最佳培养条件及有效抗菌成分,为实际生产中应用生物防治方法抑制黄曲霉污染提供新的理论依据。【方法】 通过平板对峙法及分子生物学鉴定方法对待测菌株进行筛选鉴定。以抑菌率作为衡量标准,判断所得黄曲霉颉颃菌的最佳培养温度、培养时间、接种量、转速、pH及装液量。通过硫酸铵沉淀法从颉颃菌无菌发酵上清液中提取蛋白,观测粗提物对黄曲霉菌丝生长的影响。通过离子交换色谱和凝胶过滤色谱进一步纯化粗提蛋白,并进行质谱测序及序列对比分析,筛选鉴定颉颃菌产生的有效抑菌成分。【结果】 筛选到1株解淀粉芽孢杆菌B10(菌种保藏号CCTCCNO:M2018353)。最佳培养条件为温度40 ℃,培养时间36 h,接种量3%,转速120 r/min,pH 6.0,装液量30 mL,最大抑菌率可达46.56%。其粗提蛋白能有效抑制黄曲霉生长,破坏菌丝正常形态,并从中筛选出几丁质结合蛋白、壳聚糖酶、葡聚糖酶等8种可能的有效抑菌成分。【结论】 本试验分离鉴定出1株抑制黄曲霉正常生长发育的解淀粉芽孢杆菌B10,其产生的多种蛋白成分对黄曲霉有显著抑菌活性。     

纳豆菌制剂在动物养殖中的应用

纳豆菌是生产微生态制剂的理想菌株之一,现已作为绿色饲料添加剂广泛应用于饲料。本文主要就近年来纳豆菌制剂在动物养殖中的研究与应用成果作一概述,以期为畜牧生产提供参考。     

变质鸡蛋中蜡样芽孢杆菌的分离与鉴定

从山东地区保存超过14 d大范围出现变质鸡蛋中分离到一株细菌,经过培养特性、生理生化鉴定和16S rDNA鉴定,鉴定为蜡样芽孢杆菌(Bacillus cereus).分别将变质鸡蛋、煮熟的变质蛋、健康鸡蛋进行厌氧培养和细菌计数,发现健康鸡蛋和煮熟的变质蛋无蜡样芽孢杆菌,而变质鸡蛋中的细菌数量达到1.3×108CFU/g.本试验表明,蛋黄中过量的蜡样芽孢杆菌可能与鸡蛋变质有关,应注意过量添加蜡样芽孢杆菌可能影响蛋品的保鲜和食用安全性.     

Characterization and partial purification of a bacteriocin‐like substance produced by thermophilic Bacillus licheniformis H1 isolated from cow manure compost

The production and partial characterization of bacteriocin‐like substances (BLSs) produced by bacteria isolated from cow manure compost were investigated. Eight BLS producers, which exhibited inhibitory activity against pathogenic bacteria, were isolated from cow manure compost at different stages of the composting process. The pile temperature ranged from 9.1°C to 73.2°C. The BLSs showed thermostability, but the BLS producers were not thermostable except for the H1 producer. Thermophilic Bacillus licheniformis H1 was further characterized. The culture supernatant of B. licheniformis H1 exhibited antagonistic activity against various species of Gram‐positive bacteria such as Listeria monocytogenes ATCC19111 but not against Gram‐negative bacteria except Pseudomonas fluorescens ATCC11251. Inactivation of bacteriocin‐like activity by α‐chymotrypsin, trypsin, and papain was highly significant (P < 0.001). The BLS was found to be stable under a pH range from 3 to 9 and at temperatures up to 75°C for 60 min, but it lost activity after being autoclaved at 121°C for 15 min. The optimum production of BLS by B. licheniformis H1 was obtained at a temperature of 55°C. Sodium dodecyl sulfate – polyacrylamide electrophoresis analysis of concentrated partially purified supernatants collected after resting the bacterial cells at 55°C revealed a bacteriocin‐like protein with a molecular mass of approximately 3.5 kDa. This study is the first report of a BLS from thermophilic B. licheniformis with an animal compost origin.     

A strain of Bacillus subtilis stimulates sunflower growth (Helianthus annuus L.) temporarily

Preliminary studies showed that a Bacillus subtilis strain stimulates plant growth. We investigated how inoculating seeds of a sunflower cultivar (Helianthus annuus L.) with this strain stimulated plant growth, soil properties and emissions of greenhouse gasses, i.e. carbon dioxide (CO₂) and nitrous oxide (N₂O), when cultivated in a greenhouse. Unfertilized sunflowers or fertilized with urea served as controls. After one month, root length and fresh and dry root weight of the sunflower was significantly higher in the bacteria amended plant than in the urea and unfertilized plants. However, at harvest, no positive effect was observed. The number of seeds per plant and seed weight was not significantly different between the treatments, but total plant N was significantly higher in urea-amended plants than in unfertilized plants. The CO₂ production rate was not affected by treatment, but the N₂O emission rate was significantly higher in soil amended with urea plus bacteria soil compared to the unfertilized treatments. It was found that the B. subtilis strain used in this study had a positive, but only temporarily effect on growth of the sunflower cultivar used.     

L型蜡样芽抱杆菌对草莓防御酶活性变化的影响

以易感白粉病的草莓品种"丰香"为试材,向草莓叶柄注射L型蜡样芽孢杆菌,测定了草莓叶片中SOD、POD、PPO及PAL 4种防御性酶活性的变化及白粉病感染情况。结果表明:注射L型蜡样芽孢杆菌后,4种防御性酶的活性均有不同程度的升高。