生物炭载Bacillus subtilis菌粒对连作芹菜生长的影响

为解决土壤连作障碍对蔬菜生长发育的不利影响,本研究以连作3年的芹菜土壤为研究对象,采用随机区组试验,设置5种处理:单独施加生物炭(BC)、单独施加Bacillus subtilis菌剂(BS)、生物炭与菌剂混合施加(BB)、施加生物炭载B.subtilis菌粒(BP)、不施加生物炭与菌剂(CK),盆栽种植芹菜,测定其生长与品质指标,探究生物炭和B.subtilis对连作芹菜生长的影响。结果表明,BB、BP处理组芹菜的生长和品质指标都高于其他土壤处理组,BP处理组的芹菜鲜质量、可溶性蛋白含量以及纤维素含量均显著高于BB处理组,分别为60.25 g/棵、27.25 mg/g、2.48%,其他指标两处理间无显著差异。不同土壤处理组芹菜的生长和品质指标都高于CK处理,其中BP处理组各指标值最高,尤其是芹菜鲜质量,增幅高达226.56%。因此,施加生物炭载B.subtilis菌粒提高了连作芹菜生长指标与品质,为农业生产上缓解蔬菜连作障碍奠定了理论基础。

Optimizing the Bacillus thuringiensis(Bt)protein concentration in cotton:Coordinated application of exogenous amino acids and EDTA to reduce spatiotemporal variability in boll and leaf toxins

During the boll formation stage,cotton bolls exhibit the lowest expression of Bacillus thuringiensis(Bt)insecticidal proteins.Resistance to insects varies notably among different organs,which poses challenges for controlling cotton bollworms.Consequently,an experimental strategy was designed in the 2020-2021 cotton growing season to coordinate the enhancement of protein synthesis and the attenuation of degradation.Two Bt cultivars of Gossypium hirsutum,namely the hybrid Sikang 3 and the conventional Sikang 1,were used as test materials.Three treatments were applied at the peak flowering period:CK(the control),T1(amino acids),and T2(amino acids and EDTA).The results show that,in comparison to the CK group,the Bt protein contents were significantly increased in both cotton bolls and their subtending leaves under the T1 and T2 treatments.The maximum levels of increase observed were 67.5%in cotton bolls and 21.7%in leaves.Moreover,the disparity in Bt protein content between cotton bolls and their subtending leaves notably decreased by 31.2%.Correlation analysis suggested that the primary physiological mechanisms for augmenting Bt protein content involve increased protein synthesis and reduced protein catabolism,which are independent of Bt gene expression levels.Stepwise regression and path analysis revealed that elevating the soluble protein content and transaminase activity,while reducing the catabolic enzyme activities,are instrumental in enhancing the Bt protein content.Consequently,the coordinated application of amino acids and EDTA emerges as a strategy that can improve the overall resistance of Bt cotton and mitigate the spatiotemporal variations in Bt toxin concentrations in both cotton bolls and leaves.

Animal Safety Test of Bacillus thuringiensis BT Protein

[Objectives]To determine the biological safety of BT protein from Bacillus thuringiensis(Bt)fermentation broth to mammals at high doses.[Methods]Healthy mice were randomly divided into 4 groups with 10 mice in each group.The experimental groups were fed with Bt fermentation supernatant at 0.2,0.6 and 1.0 mL/kg,respectively,once a day for 7 consecutive days.The blank control group was fed normally without intragastric administration.[Results]There was no significant difference in blood routine and blood biochemical analysis between the experimental group and the control group.After intragastric administration,the mice were dissected,and no obvious pathological changes were found;the heart,liver,spleen,lung and kidney were taken to make tissue sections,and no pathological changes were found by microscopic observation.[Conclusions]Mice can tolerate high doses of BT protein from B.thuringiensis fermentation broth.

Enhanced extracellular production of alpha-lactalbumin from Bacillus subtilis through signal peptide and promoter screening

Alpha-lactalbumin(α-LA)is a major whey protein found in breast milk and plays a crucial role in the growth and development of infants.In this study,Bacillus subtilis RIK1285 harboring AprE signal peptide(SP)was selected as the original strain for the production ofα-LA.It was found thatα-LA was identified in the pellet after ultrasonic disruption and centrifugation instead of in the fermentation supernatant.The original strain most likely only producedα-LA intracellular,but not extracellular.To improve the expression and secretion ofα-LA in RIK1285,a library of 173 homologous SPs from the B.subtilis 168 genome was fused with target LALBA gene in the pBE-S vector and expressed extracellularly in RIK1285.SP YjcN was determined to be the best signal peptide.Bands in supernatant were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purified by nickel column to calculate the highest yield signal peptide.In addition,different promoters(P_(aprE),P_(43),and P_(glv))were compared and applied.The results indicated that the strain RIK1285-pBE-P_(glv)-YjcN-LALBA had the highestα-LA yield,reaching 122.04μg/mL.This study demonstrates successful expression and secretion of humanα-LA in B.subtilis and establishes a foundation for simulating breast milk for infant formulas and developing bioengineered milk.

氨肽酶生产菌株Bacillus subtilis LBJ4-5的全基因组测序及基因功能分析

本研究从郫县豆瓣中分离获得一株高产氨肽酶菌株B. subtilis LBJ4-5,通过溶血性试验及抗生素敏感性试验评估了其安全性。同时,采用Illumina二代测序技术和第三代高通量Pacbio测序平台对B. subtilis LBJ4-5进行全基因组测序,获得其基因组特征信息,并通过COG、GO、KEGG、CAZY、CARD和VFDB等数据库进行基因预测及功能注释,以及评价其氨肽酶生产性能和安全性。结果显示,B. subtilis LBJ4-5经48 h摇瓶培养后发酵上清中的氨肽酶活达到179.23 U/mL,菌株无溶血活性且对头孢唑林、万古霉素、青霉素G、头孢氨苄等10种抗生素均高度敏感(直径≥20 mm),显示出良好的安全性。B. subtilis LBJ4-5的基因组由一条环状闭合DNA及一个环状质粒组成,大小为4053926 bp,GC含量为43.66%,共预测到4285个蛋白质编码基因、85个tRNA基因、33个rRNA基因、119个sRNA。在COG、GO、KEGG、CAZY、CARD和VFDB数据库中分别注释到3386、2581、2552、144、256和401个功能基因。进一步的信息挖掘分析表明,B. subtilis LBJ4-5的基因组中含有31个氨肽酶编码基因。而毒力基因与耐药性基因的预测分析,进一步证实了B. subtilis LBJ4-5菌株的安全性。综上,B.subtilis LBJ4-5可用作发酵食品加工的发酵菌剂。

Research Progress of Antimicrobial Peptides and the Potential Applications of Bacillus subtilis

This paper presents a comprehensive account of antimicrobial peptides (AMPs) derived from various sources, including animal, plant, and microbial origins, along with an examination of their structural characteristics and biological activities. Specifically, the potential of Bacillus subtilis as a safe and effective host for the production of AMPs is discussed. B. subtilis exhibits a notable capacity for protein secretion and is also capable of efficiently producing AMPs without the presence of endotoxin contamination. The research indicates that the production efficiency of AMPs derived from B. subtilis can be significantly enhanced through the application of genetic engineering and synthetic biology techniques. This advancement holds considerable potential for applications in food preservation, agriculture, medicine, and various other fields. The paper additionally investigates the stability of AMPs under diverse conditions of temperature, pH, and enzymatic treatment, and highlights the necessity for further research to facilitate the advancement of these AMPs for practical applications.

Bacillus subtilis 168中亚硝酸盐还原酶基因的敲除及表型鉴定

该研究首先通过同源重组方式将Bacillus subtilis 168菌株nir基因位点置换为两端具有同向排列的loxP序列选择性标记基因,再运用Cre重组酶将两个loxP间的全部序列切除,成功敲除了Bacillus subtilis 168菌株亚硝酸盐还原酶(nitrite reductase,NiR)的3个亚基基因nasB、nasD和nasE。其中,敲除nasD基因的B.subtilis 168菌株在不同生长时期均未分解培养基中亚硝酸盐,表明该nasD基因缺陷型菌株NiR活性已被完全消除,不再具备降解亚硝酸盐的能力。

AaPGRP-SC2在埃及伊蚊抗Bti杀虫晶体蛋白Cry4Ba和Cry11Aa侵染中的功能

【目的】研究AaPGRP-SC2在埃及伊蚊抵御Bti杀虫晶体蛋白Cry4Ba和Cry11Aa侵染中的功能,为研发新一代生物杀虫剂提供理论指导。【方法】采用实时荧光定量PCR(qRT-PCR)技术,分析埃及伊蚊4龄幼虫感染Bti杀虫晶体蛋白Cry4Ba和Cry11Aa后,不同时间点体内AaPGRP-SC2、抗菌肽基因及Toll通路和免疫缺陷(IMD)通路相关基因的表达情况。同时,在蚊虫体外原核表达AaPGRP-SC2,并采用SDS-PAGE结合Western blot检测纯化蛋白的质量;利用Far Western blot检测AaPGRP-SC2与Cry4Ba和Cry11Aa的结合情况。【结果】埃及伊蚊4龄幼虫感染Cry4Ba和Cry11Aa 2 h后,AaPGRP-SC2基因表达量与对照相比均显著上升,但在12 h后,Cry4Ba处理组的AaPGRP-SC2表达量下降,而Cry11Aa处理组的AaPGRP-SC2表达量继续升高。在Cry4Ba和Cry11Aa侵染2 h后,埃及伊蚊4个抗菌肽基因CecA、Att、Dipt和DefA以及Toll通路3个下游基因Spz2、Tube、Toll1A的表达量显著上升,但IMD通路下游基因中只有Cry4Ba处理组的Dredd和Cry11Aa处理组的Ankyrin1的表达量显著上升;12 h后,4个抗菌肽基因CecA、Att、Dipt和DefA以及Toll通路3个下游基因Spz2、Tube、Toll1A的表达量仍高于对照,而IMD通路下游基因中只有Cry11Aa处理组的Ankyrin1表达水平显著上调;不论侵染时间长短,IMD通路下游基因中Ankyrin2、Ankyrin3、Kenny和UevlA基因的表达量与对照相比均无显著差异。此外,成功表达了AaPGRP-SC2蛋白,并纯化得到Cry4Ba和Cry11Aa两个杀虫晶体蛋白;Far Western blot检测显示,AaPGRP-SC2可与Cry4Ba和Cry11Aa结合。【结论】AaPGRP-SC2可激活Toll通路并产生抗菌肽,但在调控IMD通路并产生抗菌肽的过程中基因表达变化不显著。

Bacillus subtilis fmbJ脂肽类抗菌物质的分离和鉴定

对BacillussubtilisfmbJ脂肽类抗菌物质的分离和鉴定进行了系统研究。通过HPLC层析确定BacillussubtilisfmbJ抗菌物质由多种组分构成,其中含有保留时间与surfactin相似的成分。通过TLC层析和原位酸解确定BacillussubtilisfmbJ抗菌物质含有两个具有闭合肽键类的物质,其中之一为迁移率Rf与标样surfactin非常相近的组分。通过ESI-MS分析检测到BacillussubtilisfmbJ抗菌物质含有分子量与fengicin相同的m/z1449.9、m/z1463.8、m/z1477.8、m/z1491.9和m/z1505.9五种同系物,和分子量与surfactin相同的m/z1008.8、m/z1022.8和m/z1036.8三种同系物。

Bacillus subtilis fmbR抗菌物质的分离和鉴定

【目的】对Bacillus subtilis fmbR产生的抗菌物质进行分离和鉴定研究,以确定抗菌物质的组成和结构。【方法】采用HPLC和TLC层析对Bacillus subtilis fmbR抗菌物质进行分离纯化,通过ESI-MS和MALDI-MS分析对抗菌物质的组成和结构进行初步鉴定。【结果】HPLC层析表明了Bacillus subtilis fmbR抗菌物质含有保留时间与surfactin相似的成分。TLC层析和原位酸解证明了Bacillus subtilis fmbR抗菌物质含有闭合肽键类的物质,其中之一为相对迁移率Rf与标样surfactin相近的组分。采用ESI-MS分析检测到Bacillus subtilis fmbR抗菌物质含有分子量与surfactinA相同的m/z1009.1、m/z1023.2和m/z1037.0等3种同系物;通过MALDI-MS分析获得[M+H]+为m/z 3403.95抗菌物质,该物质分子量与Bacillus subtilis 168产生的细菌素subtilosin的m/z3403.3相同。【结论】Bacillus subtilis fmbR抗菌物质由C13～C15的3种surfactinA同系物和一种羊毛硫抗生素subtilosin组成。

Screening for the Strain Highly Producing Antagonistic Substance from Bacillus subtilis B47 by UV Mutagenesis

[Objective] The aim of this study was to breed new strains which have higher inhibitory effects on the pathogens of watermelon fusarium wilt.[Method] The endophytic Bacillus subtilis B47 strain was obtained from tomato stems by UV mutagenesis for two consecutive times,then genetic stability as well as physiological and biochemical properties of mutant strains were studied.[Result] The antibacterial activity of all the three mutant strains F303,F304 and F305 was higher than that of B74 strain.After subculture of 10 successive generations,the antibacterial activity of all the three mutant strains for the pathogens of watermelon fusarium wilt decreased,but the antibacterial activity of F305 strain decreased the least,indicating its best genetic stability among the tested strains.The antibacterial circle diameter of F305 strain was 5 mm larger than that of wild strain B47 under the same condition.The mutant strain F305 was in logarithmic growth phase within 36 h and in stationary phase within 36-96 h,while its optimum growth temperature was 35 ℃.F305 strain could grow in sodium salt with the concentration of 1%-10%,but it grew best at the concentration of 1%.Physiological and biochemical responses of F305 strain were in accordance with those of wild strain B47.[Conclusion] This study lays the foundation for the factorial production of antagonistic substance by B47 strain and new methods of preventing from the pathogens watermelon fusarium wilt.

Bacillus subtilis B2产1-脱氧野尻霉素(DNJ)发酵条件优化

为探索制备含有1-脱氧野尻霉素(1-deoxynojimycin,DNJ)的降血糖功能性食品的新方法,以产DNJ的菌株Bacillus subtilisB2为初始菌株,以价廉的农产品加工副产物豆渣为原料,通过对发酵条件的优化,获得富含功能因子DNJ的发酵液。结果表明:接种量对α-葡萄糖苷酶抑制活性影响不明显,当接种量大于104个/mL时,发酵液的α-葡萄糖苷酶抑制活性均在20以上。而豆渣浓度、发酵温度、培养基初始pH值及发酵时间对发酵液α-葡萄糖苷酶抑制活性影响较大,在豆渣质量浓度30mg/mL,初始pH值6～8,发酵温度40℃的条件下发酵48h,发酵液表现出较高的α-葡萄糖苷酶抑制活性。以Bacillus subtilisB2发酵豆渣的发酵液为原料开发含DNJ的降糖功能食品,可以大大提高豆渣的利用价值,为降糖功能食品的开发利用开辟新途径。

Screening of Two Biocontrol Strains of Bacillus subtilis against Ginseng Soil-borne Disease and Their Antifungal Activities

[ Objective] The paper was to obtain biocontrol strains with good control effects against ginseng soil-borne disease through screening. [ Method] Dilu- tion plate method and plate confrontation culture method were used to isolate and screen biocontrol bacteria from the rhizosphere soil of diseased ginseng. The strains were identified through morphology, physiological and biochemical characteristics and 16S rDNA. [ Result ] With Rhizoctonia solani, Fusarium oxysporum and Fu- sarium solani as the indicator strains, two biocontrol strains B59 and X1 with strong antagonistic effects were screened from the rhizosphere soil of diseased ginseng in Tieli farm of Heilongjiang Province, and they were identified to be Bacillus subtilis. The inhibition rates of two biocontrol strains against eight different fungi were all greater than 90%. The primary study indicated that B59 and X1 strains could secrete antifungal active substances. [ Conclusion] Two biocontrol Bacillus subti- lis strains 1359 and X1 all had strong antagonistic effect against ginseng soil-borne disease, which had certain potential for development and utilization.

Bacillus subtilis UN_(13)产α-淀粉酶酶学性质研究

对Bacillus subtilis UN13所产生的α-淀粉酶酶学性质进行初步研究。结果表明：该酶是一种中温酸性α-淀粉酶；其最适温度为50℃，在40-60℃范围内稳定性较好；最适pH为5．5，在pH值为5．0～7．5范围内较稳定；Ca^2＋和Mn^2＋对该酶有激活作用，Cu^2＋，Zn^2＋，K^＋和EDTA则抑制该酶的活性；动力学研究表明该酶的Km值为1．7039mg／mL，Vmax值为3．1615mg／min·mL。

Separation and Purification of Recombinant Hirudin Variant 3 from Bacillus subtilis

[ Objective] The research aimed to get the optimized separation and purification conditions of the hirudin produced from Bacillus subtilis DB403 （pUBH5）. [Method] Through the systemic pretreatment, preliminary chromatography and fine chromatography. [Result]The optimized separation and purification conditions were that： Supernatant was treated by trichloroacetic acid, then by ultrafiltration desalt and anion exchange chromatography. Strong anion Q F. F. was better than weak anion DEAE F.F. The proper balanced solution was Tris-HCI （ pH 8.0）. The proper conductivity was 6 ms/cm. The maximum applied sample was 240 ATU/ml to matrix of strong anion Q F. F. This optimized procedure was magnified in strong anion exchange HiPrep 16/10Q with the 90% recovery and 70.2% purity. The purification of gel filtration of Sephacryl S-100 to hirudin was not relative to flow rate within certain scope. The application size of sample was 10 ml. The purity checked by HPLC was 95.1%, and the recovery was 93%, and the band of SDS-PAGE was single. [ Conclusion] The research provided the reference of the further industrialization separation and purification of hiruin.

Preliminary Study on Garlic Root Exudates Influences to the Growth of Pomegranate Wilt Pathogen(Ceratocystis fimbriata)and Bacillus subtilis

[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and distilled water is examined in lab to test their effect to growth of mycelia of pomegranate wilt pathogen（Ceratocystis fimbriata）and multiplication of Bacillus subtilis.[Results] The result shows that garlic root exudates whatever cultivated in MS solution or distilled water could not inhibit or promote mycelia growth of C.fimbriata.However,garlic root exudates cultivated in both methods effectively promote multiplication of B.subtilis.[Conclusions] It is suggested that intercropping garlic with pomegranate tree by combining application B.subtilis could be a promising way to prevent pomegranate wilt spread in practice.

Screening of Biocontrol Strain Bacillus subtilis by N^+ Ion Beam Implantation

[Objective] This study was to investigate the effect of N＋ ion beam implantation on the survival rate and mutation rate of biocontrol strain Bacillus subtilis. [Method] The factors influencing B. subtilis ion beam implantation, including culture time, dilution concentration, solvent, drying time of mycoderm were optimized. B. subtilis cells were implanted by using ion beam at dose of 2.0×10^14～4.0×10^14 ions/cm2 and the energy of 30 kev. Then the methods of culturing colonies confronting each other on plate and Oxford cup diffusion were used to screening strains. [Result] The optimal parameters were found as follows： culture in liquid for 20-24 h, dilution with sterile water to 106 cells/ml and drying time of 60 min for sample preparation; the optimal N＋ ion beam implantation dose of 2.0×10^14～4.0×10^14 ions/cm2 at the energy of 30 kev, the survival rate of 8.43%-26.71% and the mutation rate of 3.50%-5.43%. [Conclusion] This study provided reference for ion beam implantation mutation of B. subtilis.

Research on the Fermentation Conditions of Bacillus subtillus B-332

[Objective] The paper was to ascertain the fermentation conditions and medium formula of Bacillus subtilis B-332. [Method] Using single factor and orthogo- nal experimental designs, the fermentation medium and culture conditions for B. sub- i tills B-332 were optimized through shaking flask culture. [Result] The optimal culture and inoculation time was 18 h, and the optimized medium formula was as follows： soybean powder 0.60 g/L, sucrose 0.25 g/L, ammonium sulfate 0.07 g/L, trisodium citrate 0.03 g/L, dipotassium hydrogen phosphate 0.003 g/L, magnesium sulfate 0.005 g/L, ferrous sulfate 0.000 5%; the fermentation condition was as follows： tem- perature 30 ℃, shaking bed speed 180 r/min, shaking bottle volume 80 ml/500 ml. In the optimal fermentation conditions, the fermented spore quantity was 1.43×10^11 cfu/ml, which was 34.48 times higher than the spore quantity of 4.03×10^9 cfu/ml in initial condition. [Result] The study laid the foundation for factory production of the strain.

枯草芽孢杆菌(Bacillus subtilis)B-912对采后柑桔果实青、绿霉病的抑制效果

用从土壤中分离到的枯草芽孢杆菌 B- 912作为生防拮抗菌 ,主要研究在不同贮藏温度下不同接种时间的 B- 912活菌液、热处理液和过滤液对柑桔青、绿霉病的抑制效果。B- 912活菌液的抑菌效果最佳 ,热处理液和过滤液次之 ,但均显著地好于对照。较高的贮藏温度有利于拮抗菌对病菌的抑制作用 ,活菌液处理的果实在 2 5℃下的发病率及病斑直径均小于 15℃下的果实 ,2 4 h后接种病菌孢子的果实其发病率及病斑直径一般都高于 4 8h后接种的果实。实验证明 ,枯草芽孢杆菌的抑菌机理主要是产生抗菌素。

Curing of the Bacillus subtilis Plasmid Using Sodium Dodecyl Sulfate

Curing of Bacillus subtilis plasmid using sodium dodecyl sulfate (SDS)was studied in order to obtain a host strain. An overnight culture of Bacillus subtilis 24/pMX45 was used to inoculate fresh LB containing SDS (0-0.008%). No growth of 24/pMX45 was observed when LB contained an SDS concentration of 0.006% or greater, and the sublethal concentration (w/v) of SDS was 0.005% with a killing rate of 99%. Samples were diluted and plated on LB agar, individual colonies were randomly picked to a selective agar medium by tooth to screen for loss of plasmid-encoded erythomycin resistance. CsCl-EtBr gradient centrifugation and plasmid DNA profile demonstrated that plasmid-cured derivative A7 has completely lost its plasmid. A7 had a shorter lag, and its cell concentration was consistently higher than that of the 24/pMX45. Elimination of the plasmid was first observed after 24/pMX45 had been treated with SDS for 8 h. The percent elimination then continued to increase until about 22 h, after which the fraction of cured cell in the population remained constant. Plasmid cured cell numbers were measured in a separate control culture of 24/pMX45 untreated by SDS. No spontaneous loss of pMX45 was observed after 24/pMX45 were incubated for 24 h and 48 h with shaking at 37 ℃.These results suggested that SDS can be used as curing agent to eliminate the plasmid of Bacillus subtilis.