枯草芽孢杆菌B47高产拮抗物质菌株的紫外诱变选育(英文)

[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.     

枯草芽孢杆菌B47高产拮抗物质菌株的紫外诱变选育(英文)

[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.     

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.     

Screening of Prolific Micromonospora carbonacea in Antibiotics Production by Sodium Nitrite Mutagenesis

[Objective] The purpose of the study is to breed Micromonospora car- bonacea highly producing antibiotics and then to improve the antibiotic production. [Method] Sodium Nitrite mutagenesis, combined with rifampicin resistance screening, was used in mutation breeding of M. carbonacea highly producing antibiotics from the strain of M. carbonacea JXNU-I. [Result] The overproducing strain JXNU-1-16- Y65 was screened with the production of antibiotics 266.05% more than that of the original strain. [Conclusion] The effectiveness of sodium nitrite mutation in breeding microorganisms highly producing antibiotic was proved, and the study may lay the foundation on further development and application of the antibiotic from M. car- bonacea JXNU-1.     

棉花黄萎病拮抗细菌7-30菌株的筛选与鉴定(英文)

[Objective]The aim of this study was to screen the antagonistic spore-forming bacteria of Verticillium dahliae and identify its physiological and biochemical characteristics.[Method]Taking the cotton verticillium wilt pathogen Verticillium dahliae V-190 as the test microorganism,the antagonistic spore-forming bacteria were screened.Through the preliminary screening and secondary screening,an antagonistic bacteria strain 7-30 with stronger antibacterial activity was obtained,and its morphological characteristics,physiological and biochemical characteristics were also identified.[Result]84 antagonistic bacteria strains were isolated from soil in various places by the preliminary screening.Especially,18 strains with better antagonistic ability were screened again,so an antagonistic bacteria strain 7-30 with the diameter of inhibition zone 18.9 mm and stronger antibacterial activity was obtained.According to its morphological characteristics,physiological and biochemical characteristics,the antagonistic bacteria strain 7-30 was identified as Bacillus subtilis primarily.[Conclusion]The strain 7-30 was obtained as the antagonistic spore-forming bacteria of Verticillium dahliae.     

Comparison of Acetylcholinesterase Characteristics Between Resistant and Susceptible Strains of Helicoverpa armigera （Hubner）

The sensitivity of a susceptible and two resistant strains of cotton bollworm, Helicoverpa armigera, to phoxim, malathion and methomyl was determined by a topical application of bioassay method. YG strain, collected from field of Yanggu, Shandong Province of China, possessed 7-, 13- and 20-fold of resistance to the above three antiacetylcholinesterases based on the comparison of LD50 values with a laboratory susceptible strain. There were not significant difference of the specific activity and the Vmax value among the three strains. But the affinity of AChE tO acetylthiocholine （ATCh）, in YG strain was the lowest among the three strains tested. A cDNA encoding partial AChE gene was cloned from the three strains by RT-PCR and there was one nucleotide acid difference between YG strain and other two strains which resulted in no amino acid mutation. This partial AChE gene was used as a probe to perform Southern blot. The results indicated that there was no gene amplification in resistant cotton bollworm. Altered AChE with a decreased sensitivity to inhibitors appeared to be one of important resistance mechanisms in cotton bollworm against OP and carbamate compounds.     

高产谷胱甘肽酵母菌株的筛选及其抗乙硫氨酸诱变研究(英文)

[Objective] The aim of this study was to screen Saccharomyces for glutathione over-production. [Method] Ethionine-resistant mutants were obtained through UV mutagenesis and rational screening. [Result] A high GSH-producing strain HSJB1 was isolated from soil, and the biomass for this strain by flask shaking fermentation was 3.87 g/L while the GSH yield was 91.87 mg/L. According to the morphological, physiological and biochemical characteristics of cells, this strain was primarily identified as Saccharomyces cerevisiae. An ethionine-resistant mutant YBS77 was obtained through UV mutagenesis of the original strain HSJB1, and the biomass for this strain by flask shaking fermentation was 7.60 g dry cell weight/L while the GSH yield was 211.96 mg/L. [Conclusion] The biomass of the mutant obtained by breeding is increased by 96.38% than that of the original strain, and the GSH yield of the mutant obtained by breeding is increased by 130.72% than that from the original strain, which indicates that the breeding method is feasible.     

西瓜枯萎病土壤拮抗菌的筛选(英文)

[Objective] The aim of this study was to screen bacteria strains with stable antagonistic effect against watermelon fusarium wilt from soil and investigate the biological control of watermelon fusarium wilt by applying the antagonistic bacteria strains into soil.[Method] Actinomycete strains,fluorescent bacteria strains and bacillus strains were isolated from soil samples by the dilution-plate method,then its resistance was screened respectively by the improved confront culture method after colonies were purified.Finally,bacteria strains with better antagonistic effect were identified.[Result] 29 bacteria strains with stable antagonistic effect against watermelon fusarium wilt were screened from 39 soil samples,which contained 15 fluorescent bacteria strains,5 bacillus strains and 9 actinomycete strains.Furthermore,three antagonistic bacteria strains of FM2,FM3 and FM4 with the strongest antagonism were identified primarily.[Conclusion] According to cultural characteristics,morphological observation,biochemical and physiological tests,FM2 belongs to bacillus subtilis,while FM3 and FM4 belong to micrococcus.     

Isolation and Screening of Black Spot-Resistant Endophytic Fungi Strains from Rosa chinensis

[Objective] This study aimed to isolate and screen black-spot-resistant en- dophytic fungi strains. [Method] Various species of healthy Rosa chinensis were col- lected from Xi＇an, Xianyang, Baoji and Weinan City in Shaanxi Province. Endophytic fungi was isolated from stems and leaves, and purified by 2-3 times of inoculation to screen endophytic fungi antagonistic to Marssonina rosae with modified punching method. [Result] Samples collected from Xianyang exhibited the highest colonization rate and isolation rate; endophytic fungi strains isolated from stems presented the highest colonization rate and isolation rate compared with leaves. A total of 67 en- dophytic fungi strains were isolated from Rosa chinensis, including 3 black spot-re- sistant strains which were all derived from Baoji. [Conclusion] This study laid the foundation for further screening candidate strains of biocontrol fungi and environ- ment-friendly fungal biological control.     

Improvement of spergualin production by mutation and medium optimization

In order to screen a high-yield spergualin-production strain and an optimal fermentation medium,large numbers of isolates were selected after ultraviolet(UV)mutation and self-tolerant mutation of Bacillus laterosporus A7.A high-yield strain A-94-7 was obtained and the spergualin productivity was 4.1-fold of the parent strain.The genetic stability of the high-yield strain Bacillus laterosporus A-94-7 was very good.After fermentation medium optimization,Bacillus laterosporus A-94-7 was able to produce 380 mg?L-1.The spergualin productivity in Bacillus laterosporus A7 was increased 4.75-fold by mutation and medium optimization.     

链霉素抗性筛选吸水链霉菌高产农用抗生素菌株研究

[目的]筛选吸水链霉菌的高产农用抗生素菌株。[方法]从海南土壤中筛选出1株吸水链霉菌,以经过自然分离和2次紫外诱变的S6-7为出发菌株,经过紫外光照射辅以链霉素抗性筛选后,再进行摇瓶发酵复筛。[结果]从62株随机挑选的单菌落中初筛出7株较好菌株,经斜面连续传代3次后复筛,发现5株菌株具有较好的正突变,正突变率可达8.06%,效价最高提高25.11%。[结论]将链霉素筛选法与传统紫外诱变法相结合,使菌株的产素能力有较大提高,而且极大地提高了菌种正向突变的筛选效率。     

链霉素抗性筛选吸水链霉菌高产农用抗生素菌株研究

农用抗生素作为一类生物农药,具有使用剂量低,环境相容性好,选择性强的特点,因此受到普遍重视。目前已发现的天然抗生素有约2／3来源于链霉菌。利用链霉菌产抗生素能力与链霉素抗性基因之间的对应关系来定向筛选正向突变株,是目前农用抗生素科研领域的研究热点。     

紫外诱变吸水链霉菌选育高产农用抗生素菌株

[目的]为抗生素产生菌在农业生产中的应用奠定基础。[方法]以小麦赤霉菌为指示菌,以从吸水链霉菌海南变种S101菌株分离到的S510菌株为出发菌株,经紫外诱变后分别采用琼脂块法和二级摇瓶复筛法对其进行初筛和复筛,以选育出高产菌株,分析发酵培养基pH值和培养时间对发酵液效价的影响。[结果]当发酵培养基的pH值为5.5~6.5时,发酵液效价较高,最适pH值为6.0。发酵液的效价在72 h后可维持在较稳定的范围内,最佳发酵时间为96 h。通过连续2次紫外诱变,菌株的产抗生素能力比初始菌株提高了30.06%。将获得菌株在斜面培养基上连续传代5次后,仍有稳定的遗传性状。[结论]采用紫外诱变法选育该链霉菌是有效的。     

假丝酵母的诱变育种

[目的]通过诱变育种提高假丝酵母油脂的含量。[方法]以假丝酵母为出发菌种,利用紫外诱变、微波诱变及紫外和微波复合诱变分别对出发菌株进行诱变,筛选出生物量和吸光度均较大的菌株。[结果]酵母菌经紫外和微波诱变其生物量均比对照提高。在酵母产脂高产菌株的筛选中,微波与紫外线复合诱变是一种比较有效的方法,获得一高产酵母菌株Candida Yeast-1,其生物量比出发菌株提高率为43.3%,菌体油脂的吸光度比出发菌株提高率为32.1%。用索氏提取法测定其脂肪含量,脂肪含量提高了17.2%。[结论]对假丝酵母进行紫外、微波及复合诱变均能有效地提高其产脂率。     

卑霉素产生菌Tü-57的诱变育种研究

[目的]对卑霉素产生菌Tü-57进行诱变的育种。[方法]先对4种诱变方式的致死剂量进行筛选,再采用复合诱变的方法,用紫外线和微波2种诱变剂与链霉素和氯化锂2个底物标记物,两两结合作用于原始菌,得到诱变株,并测定其卑霉素产量。[结果]获得了一株卑霉素高产菌株ul36,其作用条件为紫外350 s,链霉素0.8μg/ml,与原始菌相比,ul36卑霉素产量提高2.58倍。诱变株经多次发酵测效价结果稳定。[结论]为将卑霉素应用于实际生产奠定了基础。     

木霉菌素产生菌的诱变育种

[目的]筛选高产木霉菌素菌株,提高木霉菌素产量。[方法]以从枸骨中分离到的产木霉菌素的内生真菌———哈茨木霉为出发菌株,进行紫外线二次复合诱变处理,将筛选出的突变菌株连续转接5代,测定其遗传稳定性。[结果]随着照射时间的延长,哈茨木霉的致死率增大,选取致死率为88.1%的紫外线照射45 s作为最适处理剂量进行诱变育种。经过2次诱变的菌株的产孢时间提前,长出的菌落更为致密。经过初筛和复筛,最终获得1株高产突变株UV-5-3,其产抗生素的水平最高,为164.75μg/m l,比初次诱变筛选获得的突变株UV-3-1提高了56.77%,是出发菌株的2.3倍。传代试验表明,突变株UV-5-3的高产性能遗传特性稳定。[结论]利用紫外线二次复合诱变处理哈茨木霉可以获得高产木霉菌素菌株。     

原生质体诱变技术选育糙皮侧耳秸秆分解菌株

[目的]为了更有效地开发利用可再生资源秸秆。[方法]以糙皮侧耳为出发菌株,采用酶解法制备原生质体,进行紫外线诱变处理,经初筛、复筛选育高效分解秸秆的菌株。[结果]随着照射时间延长,原生质体再生率下降。原生质体半致死照射剂量约为25 s。原生质体紫外诱变处理后,获得菌株08P217,其各种木质素酶酶活和纤维素酶酶活都远远高于出发菌株,木质素降解率与漆酶酶活呈明显的正相关,与木素过氧化物酶酶活和锰过氧化物酶酶活无相关性。菌株08P217的木质素和纤维素的降解率分别为出发菌株的1.75、1.71倍。[结论]菌株08P217的木质素酶酶活和纤维素酶酶活高于出发菌株,木质素和纤维素的降解能力优于出发菌株,可以作为秸秆开发利用的潜在应用菌株。     

地衣芽孢杆菌LCB-8的紫外诱变及优良菌株的选育

[目的]对地衣芽孢杆菌LCB-8进行紫外诱变,以提高其产淀粉酶、蛋白酶和纤维素酶的能力。[方法]利用紫外线进行诱变,并对诱变株淀粉酶、蛋白酶和纤维素酶的活力进行定性和定量测定。[结果]当紫外诱变的时间为30 s时,菌落的致死率达72.4%,因此紫外线照射诱变最佳时间为30 s。经初筛和复筛,得到2株较好的诱变株。其中,DY-97的淀粉酶活提高150%,蛋白酶活提高78%,纤维素酶活提高17%;DY-34的纤维素酶活提高31%,淀粉酶活提高46%,蛋白酶活提高64%。[结论]通过诱变筛选得到的DY-97可用于含蛋白质和淀粉较多的饲料发酵,而DY-34可用于含纤维素较多的饲料发酵。     

紫外诱变选育普鲁兰多糖高产菌株

[目的]选育普鲁兰多糖的高产菌株。[方法]以Aureobasidium pullulan NNG为出发菌株,采用紫外诱变的方法,筛选普鲁兰多糖高产菌株。[结果]出发菌株A.pullulan NNG摇瓶发酵所得普鲁兰多糖产量为28.79 g/L,而突变菌株UV-1产糖量为46.96 g/L,是出发菌株的1.69倍。通过突变株UV-1与出发菌株NNG发酵期内形态的观察,发现在发酵的第7天突变株UV-1膨胀细胞数达到最高。[结论]该研究可以为普鲁兰多糖高产菌株的筛选提供理论依据。     

链霉素抗性筛选井冈霉素高产菌株的研究

对井冈霉素产生菌吸水链霉菌井冈变种SJ-6(Streptomyce shygroscopicusvar. Jingganggensis Yen)进行UV和亚硝酸复合诱变,在含有菌株孢子最小抑制浓度的链霉素培养基平板上,采用链霉素抗性筛选法获得大量的链霉素抗性突变株,筛选到突变株UN-80,在摇瓶发酵条件下,井冈霉素化学效价达15 943μg/ml,比出发菌株SJ-6提高了84.4%。该菌株连续培养5代,其化学效价基本稳定,具有较好的遗传稳定性。