Control Effects of Bacillus subtilis DJ-6 and Pyraclostrobin Alone and in Combination Against Fusarium oxysporum

[Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 and pyraclostrobin alone or in combination at five ratios against Fusarium oxysporum were detected by mea-suring mycelium growth rate in laboratory tests. The growth promotion and disease control effect of combined or single use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000, 1∶2 000 and 1∶3 000 dilutions were detected in field trials. [Result] The EC50 values of combined use of B. subtilis DJ-6 and pyra-clostrobin at ratios of 1∶1, 1∶2, 1∶3, 1∶4 and 1∶5 against F. oxysporum were 5.311 5, 4.008 6, 3.570 6, 3.350 9 and 3.218 9 μg/ml, with the synergistic ratios （SR） of 2.28, 1.77, 1.53, 1.64, 1.11, among which the synergetic effect at 1∶1 was the best. The fungicidal activity of pyraclostrobin was greater than that of B. subtilis DJ-6 in laboratory tests. Field trials revealed that al the 1∶1 000, 1∶2 000 and 1∶3 000 dilu-tions of 20% pyraclostrobin·2×1011 cfu/g B. subtilis DJ-6 WP in combination, 1∶1 000 dilution of 1 ×1012 cfu/g B. subtilis DJ-6 WP and 1∶2 000 dilution of 250 g/L pyra-clostrobin EC promoted the growth of strawberry by increasing plant height, leaf petiole, leaf blade area and stem diameter. Among them, the treatments with 1∶1 000 and 1∶2 000 of 20% pyraclostrobin · 2×1011 cfu/g B. subtilis DJ-6 WP in combina-tion had better effects than other treatments. The control effects of al the treat-ments were measured 30 and 80 d after fungicide application. The control effects of 1∶1 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combina-tion were up to 100% and 93.11%, which were higher than those in al other treat-ments. The second highest control effects were found in the treatment with 1∶ 2 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination, they were 92.49% and 86.49%, higher than those in other treatments except the 1∶1 000 dilution of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 in combination. The control effects of 1∶3 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination were 82.61% and 72.42%, higher than those in treatment with 1∶1 000 dilution of 1×1012 cfu/g B. subtilis DJ-6 WP, but lower than those in treat-ment with 1∶2 000 dilution of 25% pyraclostrobin EC. [Conclusion] Al the results re-vealed that the combination use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000 to 1∶2 000 dilution had better control effect against strawberry Fusarium wilt.

Bacillus globisporus N75 6-α-葡萄糖基转移酶在枯草芽孢杆菌中的重组表达

6-α-葡萄糖基转移酶具有催化α-1,4-葡聚糖的外切水解和转糖基化功能,可通过转糖基活性产生非还原端连有α-1,6键的α-葡聚糖,可用于生产环交替糖及其分支衍生物和环异麦芽寡糖等新型功能糖。为了更好地将6-α-葡萄糖基转移酶应用于食品领域,该研究对来源于Bacillus globisporus N75的6-α-葡萄糖基转移酶在食品安全级菌株枯草芽孢杆菌中进行重组表达,并通过表达宿主的选择及优化发酵条件进一步提高重组蛋白产量。结果表明,宿主WHS9更有利于6-α-葡萄糖基转移酶的重组表达,在20℃的发酵条件下,胞内外可溶性总酶活力可达2.11 U/mL;在25℃添加20 mmol/L海藻糖发酵48 h后,总酶活力可达到2.21 U/mL;优化发酵时间后,发酵36 h总酶活力可达3.14 U/mL,是优化前WHS9表达酶活力的196倍。该研究首次实现了6-α-葡萄糖基转移酶在枯草芽孢杆菌中的重组表达。

Postharvest Biological Control of Apple Anthracnose by Bacillus subtilis BS80-6,A Mutant Strain through Ion Implantation

The original Bacillus subtilis was isolated from the soil of an apple orchard,and B. subtilis strain BS80-6,selected from Bacillus subtilis by ion implantation,was used as an antagonist for postharvest biological control against apple anthracnose（ colletotrichum gloeosporioides）. The mechanisms of action and efficacy of Bacillus subtilis strain BS80-6 against apple anthracnose caused by colletotrichum gloeosporioides were studied in vitro and on apples in controlled and semi-commercial conditions. An application of cell suspension（ 108 cells per mL） of the antagonist in artificial wounds of apples reduced growth of C. gloeosporioides after storage at different temperatures. The inhibitory actions of cell culture to hyphal growth and to spores germination were 86. 6% and 98. 65%,respectively,and the control efficacy of cell culture against the disease was 60. 34% at room temperature. The results showed that BS80-6 was more effective against apple anthracnose.The cell culture of BS80-6 received better control efficacy against apple anthracnose than culture filtrates and autoclaved cell. All treatments significantly inhibited the disease both in vitro and in vivo compared with control. Fruits treated with cell culture and stored at 10 ℃ had lower infection rate,more delayed formation of acervwlus and smaller lesion diameter than those stored at 20 ℃. There was better control efficacy in fruits inoculated with spores after application of BS80-6. The mechanisms of BS80-6 activity appeared to involve production of an antifungal substance,deformation of hyphal cell and disintegration of cell wall. Besides,BS80-6 could improve the activity of major defense enzymes of apple,such as peroxidase（ POD） and polyphenol oxidase（ PPO）.

枯草杆菌二联活菌颗粒联合斑蝥酸钠维生素B_(6)辅助治疗在慢性阻塞性肺疾病合并非小细胞肺癌中的效果研究

目的探讨枯草杆菌二联活菌颗粒联合斑蝥酸钠维生素B_(6)辅助治疗在慢性阻塞性肺疾病(COPD)合并非小细胞肺癌(NSCLC)中的效果。方法选取2020年1月—2022年10月收治的COPD合并NSCLC 60例,采用随机数字表法分为观察组和对照组各30例。2组均给予化疗联合免疫治疗,在此基础上对照组给予斑蝥酸钠维生素B_(6)治疗,观察组给予枯草杆菌二联活菌颗粒联合斑蝥酸钠维生素B_(6)治疗,2组均持续治疗4个周期。统计2组治疗4个周期后总缓解率及治疗前、治疗2个周期、治疗4个周期肿瘤因子[癌胚抗原(CEA)、癌抗原125(CA125)、血管内皮生长因子(VEGF)、缺氧诱导因子(HIF-1α)]、免疫功能指标(CD3+、CD4+、CD4+/CD8+)、肠道微生态指标(肠道菌群丰富度、多样性指数)、治疗期间毒副反应、治疗后1年生存率。结果2组总缓解率比较差异无统计学意义(P>0.05)。治疗后2组CEA、CA125、VEGF、HIF-1α呈下降趋势,CD3+、CD4+、CD4+/CD8+呈升高趋势,差异有统计学意义(P<0.05)。治疗后2组肠道菌群丰富度、多样性指数呈升高趋势,且观察组高于对照组(P<0.05)。观察组胃肠道反应发生率为16.67%(5/30)低于对照组的46.67%(14/30)(P<0.05)。2组治疗后1年生存率比较差异无统计学意义(P>0.05)。结论枯草杆菌二联活菌颗粒联合斑蝥酸钠维生素B_(6)辅助治疗能有效纠正COPD合并NSCLC患者化疗及免疫治疗后肠道菌群紊乱,改善机体免疫应答,抑制肿瘤因子表达,减少毒副反应的发生。

PCSK6、Corin在急性心肌梗死患者血清中的表达水平及其预后意义

目的探讨前蛋白转化酶枯草杆菌蛋白酶/Kexin 6型(PCSK6)、丝氨酸蛋白酶(Corin)在急性心肌梗死(AMI)患者血清中的表达水平及其预后意义。方法选取2021年3月—2022年3月长沙市第三医院收治的AMI患者153例为AMI组,根据经皮冠状动脉介入治疗1年后预后分为预后不良亚组和预后良好亚组,另选取同期80例体检健康志愿者为健康对照组。采用酶联免疫吸附法检测血清PCSK6、Corin水平;多因素Logistic回归和受试者工作特征(ROC)曲线分析血清PCSK6、Corin水平与AMI患者预后不良的关系及预测价值。结果与健康对照组比较,AMI组血清PCSK6水平升高,Corin水平降低(Z/P=6.705/<0.001、5.627/<0.001)。随访1年,153例AMI患者预后不良发生率为46.41%(71/153)。预后不良亚组血清PCSK6水平高于预后良好亚组,Corin水平低于预后良好亚组(Z/P=6.022/<0.001、5.846/<0.001);多因素Logistic回归分析显示,AMI患者预后不良的独立危险因素为年龄增加、Killip分级≥Ⅲ级、PCSK6升高,保护因素为左心室射血分数、Corin升高[OR(95%)CI=1.073(1.008~1.141)、4.400(1.383~13.997)、1.105(1.058~1.154)、0.815(0.720~0.922)、0.996(0.994~0.998)]。ROC曲线分析显示,血清PCSK6、Corin及二项联合评估AMI患者预后不良的曲线下面积分别为0.783、0.774、0.864,二项联合评估AMI患者预后不良的曲线下面积最大(Z/P=2.753/0.006、2.794/0.005)。结论AMI患者血清PCSK6水平升高和Corin水平降低与预后不良密切相关,可能成为预后的辅助评估指标。

加强表达6-磷酸果糖激酶提高Bacillus subtilis乙偶姻合成效率

乙偶姻是枯草芽孢杆菌的主要胞外产物,它是一种广泛使用的食用香精,同时也可作为重要的化学中间体,因此提高枯草芽孢杆菌乙偶姻的产量和生产效率有重要意义。本研究克隆了编码枯草芽孢杆菌6-磷酸果糖激酶(PFKA)和丙酮酸激酶(PK)的编码基因pfk A和py K,并分别将其在高产乙偶姻的枯草芽孢杆菌BM(敲除了2,3-丁二醇脱氢酶的编码基因bdh A)中过量表达。结果表明过量表达PFKA或者PK能有效提高糖酵解速率以及发酵过程的生物量,并且过量表达PFKA与过量表达PK相比更有利于乙偶姻的合成。在5 L发酵罐上对工程菌进行发酵实验发现,经底物流加发酵,乙偶姻产量达到66.8 g/L,生产效率达到0.74 g·(L·h)-1。本研究为利用枯草芽孢杆菌作为细胞工厂生产相关化合物有重要的借鉴意义。

玉米芯粉固定枯草芽孢杆菌对废水中Cr^(6+)的吸附性能研究

用玉米芯和枯草芽孢杆菌两种材料,制备了一种微生物吸附剂。以废水中Cr^(6+)的吸附率为指标,探究了在不同温度、时间、投加量和pH的条件下,玉米芯粉固定枯草芽孢杆菌对废水中Cr^(6+)的吸附产生的影响。通过响应面法确定了玉米芯粉固定枯草芽孢杆菌对废水中Cr^(6+)吸附的最佳条件。实验结果表明:玉米芯粉固定枯草芽孢杆菌在温度35℃、pH=4.7、振荡时间63 min时,对废水中Cr^(6+)的吸附效果更好,其去除率达到89.64%。

Dietary supplementation of Bacillus subtilis PB6 improves sow reproductive performance and reduces piglet birth intervals

We investigated the effects of dietary supplementation with Bacillus subtilis PB6(B.subtilis PB6)during late gestation and lactation on sow reproductive performance,antioxidant indices,and gut microbiota.A total of 32 healthy Landrace×Yorkshire sows on d 90 of gestation were randomly assigned to 2 groups,with 16 replicates per group,receiving basal diet(CON)or the basal diet+0.2%B.subtilis PB6,containing 4.0×10^8 CFU/kg of feed(BS).The litter sizes(total born)and numbers of piglets born alive were larger in the BS group(P<0.01),whereas the weights of piglets born alive and the piglet birth intervals were lower in the BS group(P<0.05).Although the litter weights and piglet bodyweights(after crossfostering)were lower after BS treatment(P<0.05),the litter sizes,litter weights,lactation survival rate,and litter weight gains at weaning were higher in BS group(P<0.05).The concentrations of malondialdehyde(MDA)in the sow sera at parturition were lower in the BS group(P<0.01).The serum total antioxidant capacity(T-AOC)at parturition and the serum catalase(CAT)concentrations on d 21 of lactation were higher in the BS group(P<0.05).Dietary supplementation with B.subtilis PB6(P<0.05)reduced the serum endotoxin concentrations in the sows and the serum cortisol concentrations of the piglets at d 14 of lactation.Theα-diversity indices of microbial were higher in the CON group(P<0.05).At the phylum level,B.subtilis PB6 supplementation increased the relative abundances of Gemmatimonadete and Acidobacteria(both P<0.01)and reduced those of Proteobacteria,and Actinobacteria(both P<0.05).At the genus level,B.subtilis PB6 supplementation increased the relative abundance of RuminococcaceaeUCG-013 cc(P<0.05)and reduced that of Streptococcus(P<0.05).This study demonstrated that adding 4.0×10^8 CFU/kg B.subtilis PB6 to sows’feed during late gestation and lactation could shorten piglet birth intervals,enhance the growth performance of suckling piglets,and improve the gut health of sows during late gestation.

枯草杆菌6-磷酸葡萄糖酸脱氢酶的分离纯化及部分性质研究

采用DEAE Sepharose离子交换层析,Blue SepharoseCL 6B特异结合层析和SephadexG 200凝胶过滤技术,对枯草芽孢杆菌中的6 磷酸葡萄糖酸脱氢酶进行了分离纯化.纯化倍数为112.3倍,比活为1.46U/mg,回收率为8.2%.纯化酶液经聚丙烯酰胺凝胶电泳检验为单一带.测得全酶相对分子质量为107kD,具有两个分子量相同的亚基,亚基相对分子质量为51kD.最适pH值为8.0,最适温度为30℃,对热不稳定.以6 磷酸葡萄糖酸和NADP+为底物,其Km值分别为Km1(NADP+)=19.8μmol/L和Km2(6 GPA)=22.6μmol/L.在5mmol/L～50mmol/L浓度范围内,Mg2+,Ca2+和Mn2+对酶有激活作用,Fe3+和Cu2+对酶有抑制作用,K+,Na+,Cl-,NO-3,SO-4对酶几乎没有影响.用PMSF,TNBS,NBS,DTT和BrAc对酶进行修饰,实验结果表明,丝氨酸、苏氨酸、赖氨酸和组氨酸残基可能是该酶活性中心的功能基团.

马来酸曲美布汀联合枯草杆菌二联活菌肠溶胶囊对肠易激综合征的疗效及对白细胞介素-6的影响

目的:观察马来酸曲美布汀联合枯草杆菌二联活菌肠溶胶囊治疗肠易激综合征的临床疗效,并观察患者血清白细胞介素-6(IL-6)水平变化情况。方法:选取本院消化内科门诊及住院部肠易激综合征患者144例,按照入院顺序编号,分为治疗组与对照组,每组各72例。对照组口服枯草杆菌二联活菌肠溶胶囊500 mg,3次/d;治疗组则在对照组的基础上口服马来酸曲美布汀0.1 g,3次/d,治疗周期为60 d,比较两组的临床疗效及IL-6水平的影响。结果:治疗组的总有效率为97.22%,对照组为83.33%,治疗组总有效率明显高于对照组,两组比较差异有统计学意义(P<0.05)。两组治疗前的IL-6水平比较差异无统计学意义(P>0.05),两组治疗后的IL-6水平均有不同程度的降低,治疗前后比较差异有统计学意义(P<0.05);治疗组降低程度明显大于对照组,两组比较差异有统计学意义(P<0.01)。两组均未见明显的药物不良反应,治疗组有2例患者在首次服用药物出现轻微恶心、口渴的症状,均自行缓解,后未见发生;对照组未见明显不良反应。结论:马来酸曲美布汀联合枯草杆菌二联活菌肠溶胶囊治疗肠易激综合征有不错的临床疗效,并且对血清IL-6的含量亦有着明显调节作用。

乙酰氨基葡萄糖合成关键酶氨基葡萄糖-6-磷酸乙酰转移酶的筛选及酶学性质分析

N-乙酰氨基葡萄糖(N-acetylglucosamine,GlcNAc)是氨基葡萄糖(Glucosamine,GlcN)的衍生物,在保健食品和医药领域具有广泛应用。氨基葡萄糖-6-磷酸乙酰转移酶(glucosamine-6-phosphate N-acetyltransferase,GNA)是N-乙酰氨基葡萄糖合成途径中的关键酶。本研究在前期构建的产GlcNAc枯草芽孢杆菌(Bacillus.subtilis,B.subtilis)工程菌的基础上,通过过量表达不同来源的GNA,筛选出来源于秀丽隐杆线虫(Caenorhabditis elegans)的氨基葡萄糖-6-磷酸乙酰基转移酶(Cegna1)最适于加强GlcNAc合成途径。在B.subtilis工程菌中表达Cegna1,摇瓶水平发酵GlcNAc产量达到7.31 g/L,与过量表达来源于酿酒酵母(Saccharomyces cerevisiae,S.cerevisiae)的GNA的对照菌株相比,GlcNAc的产量提高了24.51%。在3 L发酵罐中进行分批发酵,GlcNAc产量达到24.23 g/L,相较于对照菌株GlcNAc的产量提高了24.69%。进一步研究发现重组Cegna1对GlcN-6P和乙酰辅酶A(Ac-CoA)有着较高的亲和力和催化效率,最后对重组Cegna1的基本酶学性质进行了考察,发现底物GlcN-6P对重组Cegna1的抑制作用明显,下一步可采用定向进化策略改造Cegna1,解除底物GlcN-6P对重组Cegna1的抑制作用。本研究结果为应用定向进化策略改造GNA的实现提供了理论依据。

颠茄合剂治疗6个月内婴儿排便困难的临床效果研究

目的探讨分析应用颠茄合剂治疗6个月内幼婴排便困难的临床效果。方法选取2013年至2016年期间本地区收治的6个月内排便困难的幼婴(未明确诊断功能性或器质性便秘,对于基层医生往往缺少各项检查),其中56例作为研究对象,将其随机分为A组(24例)、B组(32例)。A组为不改变现有饮食治疗加枯草杆菌二联活菌颗粒进行治疗;B组为患儿在不改变现有饮食加用颠茄合剂进行治疗;C组为患儿不改变现有饮食治疗,当添加枯草杆菌二联活菌颗粒无效后,则改为加用颠茄合剂,共21例。记录所有患儿的临床治疗效果,整理数据结论,并回顾性分析。结果排便困难的临床缓解情况,B组及C组明显优于A组,差异具有统计学意义(P<0.05)。C组疗效与B组疗效差异无统计学意义。结论颠茄合剂治疗6个月内幼婴排便困难的临床效果明显,值得在临床上推广应用,对基层医生在未明确诊断功能性或器质性排便困难时提供新的治疗方法。

枯草芽孢杆菌YT168-6产抗菌肽sublancin的发酵工艺优化及培养基筛选的研究

研究旨在探索枯草芽孢杆菌YT168-6产抗菌肽sublancin的最适发酵条件和最适培养基组成,以期提高发酵液中sublancin含量。试验先通过单因素试验筛选出最适发酵条件,确定发酵培养基需要的无机盐、碳源、氮源,再通过正交试验、最陡爬坡试验、Box-Behnken设计的响应面分析方法确定最适发酵培养基组成。结果表明:枯草芽孢杆菌YT168-6产抗菌肽sublancin的最适发酵条件为菌种接种量1.0%、发酵温度37℃、发酵液初始pH 7.0;最适发酵培养基为K_(2)HPO_(4)5 g/L、KH_(2)PO_(4)5 g/L、MgSO_(4)10 g/L、可溶性淀粉30.2 g/L、蛋白胨23.6 g/L、玉米浆18.2 g/L;优化后sublancin产量由756μg/mL提到1581μg/mL,是优化前的2.09倍。综上所述,本研究所筛选的最适发酵条件和最适培养基可为枯草芽孢杆菌YT168-6菌株工业化生产sublancin提供技术参考。

一种源于枯草芽孢杆菌的新型甘露糖-6-磷酸异构酶的基因克隆与表达

通过PCR克隆了一种来自枯草芽孢杆菌str. 168菌株的甘露糖-6-磷酸异构酶编码基因(BSMPI-2),利用p ET-28a载体转化至大肠杆菌BL21(DE3)菌株。经IPTG诱导实现了BSMPI-2蛋白的表达,经过亲和层析纯化和聚丙烯酰胺凝胶电泳(SDS-PAGE)验证,证实目的蛋白分子量约3. 54×10~4,BSMPI-2以L-核糖为底物时的最适反应条件为pH 8. 0、60℃、外源添加0. 5 mmol/L Co^(2+),该酶催化2 h可将29%的L-核糖异构为L-核酮糖。

枯草芽胞杆菌和吡唑醚菌酯协同防治草莓病害

为了探索化学农药在草莓病害防治上的减量使用,采用枯草芽胞杆菌DJ-6菌株的制剂(BCA)和化学农药吡唑醚菌酯(Pyraclostrobin,PS)联用来协同防治。用浊度法检测了DJ-6菌株在不同浓度PS中的敏感性。结果表明,在所有参试的浓度中,DJ-6菌株都能生长。田间防治结果表明,BCA能有效降低PS的使用浓度,BCA单用能防治草莓炭疽病和草莓白粉病,但防效低于PS在标准施用剂量下的防效。然而,BCA与PS联用后能减少50%的PS的施用量。BCA与PS联用后能提高DJ-6在草莓叶围的存活率。两者联用后草莓叶片中过氧化酶、多酚氧化酶、苯丙胺酸裂解酶、β-1,3-葡聚糖酶活性显著上升了近2倍。

Toxicity Test and Field Control Effects of 4 Different Fungicides on Grape Downy Mildew

[Objective] This study was conducted to investigate the biocontrol activity of Streptomyces corchorusii strain NF0919 and Bacillus subtilis D J-6 WP to grape downy mildew. [Methed] We determined the indoor toxicity of the supernatant of S. corchorusii strain NF0919, 1.0×1011 cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph on Plasmopara viticola by the leaf disc method, respectively, and a field efficacy trial was conducted. [Result] The results showed that the ECso values of the supernatant of strain NF0919, 1.0×1011cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph were 96.285 9, 86.603 8, 69.947 2 and 7.263 6 μg/ml, respec- tively. The values of field efficacy in preventive experiments for grape downy mildew on the 7th day after 2 times of spraying 20 times diluent of the supernatant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 71.55% and 70.71%, respectively, and the values of field efficacy on the 14th day after the 2 times of fungicide application were 67.54% and 68.19%, respectively. The values of field efficacy in curative experiments on the 7th day after 2 times of spraying 20 times diluent of the supematant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 59.72% and 56.07%, respectively, and the val- ues of field efficacy on the 14th day after the 2 times of fungicide application were 56.88% and 57.46%, respectively. The field efficacy values of the 2 tested biocon- trol agents were equivalent. The protective effect showed no significant difference between each of tested biocontrol agents and 300 times diluent of 50% mancozeb WP, but there was a significant difference in the efficacy between each of tested biocontrol agents and 200 times diluent of 40% dimethomorph SC. [Conclusion] The S. corchorusii strain NF0919 and B. subtilis D J-6 WP had certain biocontrol poten- tial to grape downy mildew and development value.

4种杀菌剂对葡萄霜霉病菌的毒力及田间防效

为探明黄麻链霉菌NF0919菌株和枯草芽孢杆菌DJ-6对葡萄霜霉病的生防活性,采用叶盘法分别测定黄麻链霉菌NF0919发酵上清液、1.0×10^(11)cfu/g枯草芽孢杆菌DJ-6 WP、代森锰锌和烯酰吗啉对葡萄霜霉病菌的室内毒力,并进行防治葡萄霜霉病的田间试验。结果表明:NF0919菌株发酵上清液、1.0×1011cfu/g枯草芽孢杆菌DJ-6 WP、代森锰锌和烯酰吗啉对葡萄霜霉病菌孢子萌发抑制的EC_(50)值分别为96.2859、86.6038、69.9472、7.2636μg/m L。NF0919菌株发酵20倍液和1.0×10^(11)cfu/g枯草芽孢杆菌DJ-6WP1000倍液对葡萄霜霉病做预防性施药时,2次药后7天的防效分别为71.55%和70.71%,2次药后14天的防效分别为67.54%和68.19%;当做治疗性施药时,2次药后7天的防效分别为59.72%和56.07%,2次药后14天的防效分别为56.88%和57.46%。2种供试生防菌剂的防效相当,且保护效果与50%代森锰锌WP 300倍液均差异不显著,而治疗效果与40%烯酰吗啉SC 200倍液均差异显著。可见,黄麻链霉菌NF0919菌株和枯草芽孢杆菌DJ-6 WP对葡萄霜霉病具有一定的生防潜力与开发的价值。

枯草芽孢杆菌对废水中Cr^(6+)的吸附特性研究

选用枯草芽孢杆菌作为吸附剂,通过静态吸附实验,探究了不同影响因素下枯草芽孢杆菌对废水中Cr^(6+)的吸附特性。结果表明:枯草芽孢杆菌在8 h后进入对数期,当温度为37℃、pH=7、Cr^(6+)浓度为2 mg/L、转速为150 r/min时吸附效果最佳,最大吸附量为5.69 mg/g,且枯草芽孢杆菌对Cr^(6+)的吸附在48 h时达到平衡。此外,用多个模型对吸附动力学结果进行拟合,除了准一级动力模型外,其余均能达到显著的效果;傅里叶红外光谱显示,枯草芽孢杆菌细表面的羧基、羟基等不饱和烃类,对Cr^(6+)的去除起到主要作用.

诊断用耐热尿酸氧化酶菌株的筛选及条件优化

目的分离筛选及鉴定产耐热尿酸氧化酶的菌株,优化发酵条件并研究酶学性质。方法利用透明圈法从高温酒曲中筛选产耐热尿酸氧化酶的菌株,扩增菌株16S rDNA序列并构建系统发育进化树进行鉴定,优化菌株产尿酸氧化酶的发酵条件并研究该酶的酶学性质。结果筛选获得一株产耐热尿酸氧化酶的菌株,经分子鉴定命名为Bacillus subtilis ZX-6。于优化后的最佳发酵产酶条件下(30℃、初始p H 8.1、4 m L/L玉米浆)尿酸氧化酶水平达135.9 U/L,比优化前提高了133.7%。该酶最适反应温度及p H分别为45℃和7.6,于37℃保温48 h后,其剩余酶活仍为17.2%,具备良好的热稳定性。结论产耐热尿酸氧化酶菌株筛选及发酵条件优化的成功为进一步的研究奠定了良好的基础。

常压室温等离子体和紫外诱变选育腺苷高产菌株

腺苷是一种内源性核苷类物质,在生理生化过程中起着重要的调控作用。使用常压室温等离子体(ARTP)诱变、UV-LiCl诱变和复合诱变,将诱变后的菌株涂布在含最低致死浓度的6-巯基嘌呤(6-MP)抗性平板和不含该抗性的平板上,35℃培养1~2d后对其抗性正突变株进行发酵筛选和传代稳定性考察,获得1株腺苷高产菌株A-Z-L-2,传代6次后其腺苷产量达到20.512g/L,较出发菌株BS-0腺苷产量提高了16.12%,且该菌株具有较好的传代稳定性。