医疗废弃物电子束辐照灭菌处理效果

利用电子束对医疗废弃物进行不同剂量的辐照处理,并以短小芽孢杆菌和枯草芽孢杆菌作为微生物指示菌,通过微生物计数检验灭菌效果,分析吸收剂量和医疗废弃物材质对微生物灭活效果的影响。结果表明：吸收剂量与存活微生物菌对数值线性相关。短小芽孢杆菌和枯草芽孢杆菌的D₁₀值分别为2.45 kGy和1.22 kGy。吸收剂量为15 kGy时,医疗废弃物模拟物上的短小芽孢杆菌和枯草芽孢杆菌杀灭对数值达到6,满足现行医疗废弃物微波和化学消毒技术规范的处理要求。     

快中子辐照对枯草芽孢杆菌的灭菌效果研究

利用快中子脉冲堆(Chinese Fast Burst ReactorⅡ,CFBR-Ⅱ)产生的快中子,采用枯草芽孢杆菌黑色变种为材料,考查了中子辐射灭菌效果及剂量、剂量率、辐照温度、照射状态等辐射灭菌影响因素.结果表明,在剂量率为7.4 Gy/min时的D10值为384.6Gy,中子剂量与存活芽孢对数满足y=-0.0026x 10.462的函数关系;在剂量为800Gy时,剂量率与存活芽孢对数满足y=7.7414X-0.0834的函数关系;升高温度有利于中子辐射灭菌;中子辐照不同状态芽孢,其存活率为:菌片＞粉末＞液体.     

枯草芽孢杆菌耐辐射菌株对紫外线的耐受性及其机理初探

为探讨枯草芽孢杆菌对紫外线的耐受性,以枯草芽孢杆菌耐辐射菌株及其来源菌株枯草芽孢杆菌黑色变种为研究材料,以不同剂量紫外线辐照处理。采用平板计数法比较两种菌株的存活率,通过脉冲场凝胶电泳分析两种菌的DNA双链断裂（Double strand breaks,DSBs）o发现,对数期耐辐射菌株对紫外线的耐受性明显大于原菌株,耐辐射菌株DSBs水平小于对应的原菌样品。耐辐射菌株对紫外线的耐受性较强,其DNA双链断裂程度与辐照剂量及辐照样品密切相关。     

细菌辐射杀伤的D_(10)值测定及牛黄解毒粉的辐射灭菌效果观察

采用~(60)Coγ射线照射,对短小芽胞杆菌E_(601)菌株片及金黄色葡萄球菌、绿脓杆菌、大肠杆菌进行D_(10)值(即杀灭90%细菌所需剂量)测定,以及对中药牛黄解毒粉进行辐照灭菌观察。结果表明,以上各菌辐射杀伤的D_(10)值分别为2.1、0.17、0.07和0.08kGy,牛黄解毒粉经10kGy辐照后,能达到灭菌效果。     

UVC诱导的枯草芽孢杆菌DNA双链断裂及影响因素探讨

为探讨短波紫外线（Ultraviolet C,UVC）对枯草芽孢杆菌基因组DNA的损伤效应,探讨研究方法和材料对结果的影响,以枯草芽孢杆菌为研究材料,分别对其菌体样品及DNA样品进行不同剂量的UVC辐照,采用8h、16h、24h脉冲场凝胶电泳分离DNA片段。结果发现,16h脉冲场凝胶电泳最能反映DNA的双链断裂程度。对16h电泳图进行数据分析发现,随UVC辐照剂量的增大DNA释放百分比递增;菌体样品在辐照剂量17．8J／cm^2处其DNA双链断裂产额最大,而DNA样品的最大双链断裂产额出现在辐照剂量为72．7J／cm^2处;另外,同辐照剂量下菌体样品的释放百分比和菌体DNA双链断裂产额均高于DNA样品。结果表明,UVC诱导的枯草芽孢杆菌DNA双链断裂程度与辐照剂量及辐照样品密切相关。     

重离子辐照诱变增强枯草芽孢杆菌纤维素降解能力

为了提高枯草芽孢杆菌纤维素降解能力,本实验从5株枯草芽孢杆菌中筛选出一株纤维素降解率较高的菌株作为出发菌株,利用12C6+离子束辐照诱变处理后,采用刚果红染色法进行初筛,通过测定纤维素降解率及内切葡聚糖苷酶活力进行复筛,对选出的高纤维素降解率菌株进行发酵条件优化。最终得到一株Bacillus subtilis CG-40-1突变株,其纤维素降解率为(53.07±0.75)%,较出发菌株提高了17.75%,并具有良好的纤维素降解稳定性。经过发酵条件优化,最终得到该菌株的最适发酵时间、温度和pH分别为120 h、45℃、6.5,纤维素降解率为(67.79±0.49)%,较未优化时提高27.74%。     

氧化亚铁硫杆菌与氧化硫硫杆菌在四价铀浸出中作用研究

采用广东某矿低品位铀矿石,在相同的培养条件下,研究了氧化亚铁硫杆菌与氧化硫硫杆菌对U4 的浸出作用。研究结果表明,在氧化亚铁硫杆菌作用下铀的浸出率比在氧化硫硫杆菌作用下高21.34%;氧化亚铁硫杆菌为UO2的氧化提供了高效氧化剂,而氧化硫硫杆菌则显著降低了浸矿体系的pH值,对UO22 的络合析出非常有利。因此,氧化亚铁硫杆菌与氧化硫硫杆菌对U4 的浸出具有互补作用。     

细菌辐射杀伤的D10值测定及牛黄解毒粉的辐射灭菌效…

采用６０Ｃｏγ射线照射，对短小芽胞杆菌Ｅ６０１菌株片及金黄色葡萄球菌，绿脓杆菌，大肠杆菌进行Ｄ１０值（即杀灭９０％细菌所需剂量）测定，以及对中药牛黄解毒粉进行辐照灭菌观察。结果表明，以上各菌辐射杀伤的Ｄ１０值分别为２．１，０．１７，０．０７和０．０８ｋＧｙ，牛黄解毒粉经１０ｋＧｙ辐照后，能达到灭菌效果。     

地球微生物学在墨西哥矿藏勘查中的应用

本文介绍了运用地球微生物学方法寻找多金属矿化,尤其是金矿化中的主要研究成果。在墨西哥境内选择了6种不同的矿化类型。土壤中蜡样芽孢杆菌与异常金属富集的空间分布使我们发现蜡样芽孢杆菌含量与某些矿化相关并且在某种程度上可能与地下矿化中亲铜元素的总含量成正比。在矿藏丰富的土壤中观察到,高蜡样芽孢杆菌含量与高金属含量之间存在着空间间隔或称“水平偏移”。对这一空间间隔的可能解释是局部中毒效应,它超出了土壤微植物群的适应能力,或者是一种是由铁-锰氧化物、氢氧化物中亲铜元素占优势连同其他原因一道而引起的生物速效性的降低。如果同一天进行多次测试,该方法的重现性是令人满意的。一般地说所观察到的蜡样芽孢杆菌计数随研究时期样品储存时间的延长而减少。尽管蜡样芽孢杆菌分布不足以替代地球化学分析,这些有效的定性数据充分地说明应该更进一步地研究此方法。目前,蜡样芽孢杆菌方法可作为一种有益的勘查补充技术。某些结果说明蜡样芽孢杆菌方法在寻找隐伏多金属矿化的潜在能力。     

矿产勘探的微生物方法:梅斯基特矿床的矿例

一种使用土壤中的特殊细菌——蜡样芽孢杆菌勘探金矿的好方法已经在沙漠灌木、北方森林等地的许多矿床上试验成功。本文给出了在美国加利福尼亚州南部的梅斯基特浸染型金矿床上使用土壤蜡样芽孢杆菌、土壤金地球化学、牧豆树(Larrea Tridentata)金地球化学进行定位测量的结果。矿化基岩出露地表,并延伸到冲积层下100m深。分析了土壤样品和牧豆树植物样品中的金,以确定是否可用金含量作为勘探的标志。结果表明,在已知埋藏浸染状矿的位置,蜡样芽孢杆菌孢子数增加。在牧豆树植物底部收集的土壤样品中的金含量确定了矿体在地表和深部的走向。牧豆树植物的金含量只能确定矿化基岩的地表露头。在这一极端干旱地区的条件下勘探埋藏矿床的有效方法,应该包括在植物下取土壤样品并分析土壤中的金含量和蜡样芽孢杆菌含量。     

Study on Mutagenic Breeding of Bacillus Subtilis and Properties of Its Antifungal Substances

Bacillus subtitles JA isolated by our laboratory produced a large amount of antifungal substances, which had strong inhibitory activity against various plant pathogenic fungi,such as Rhizoctonia solani, l?usarium graminearum and so on. Ion beam implantation as a new mutagenic methods was applied in our studay. After B. subtitles JA was implanted by N^ ions,a strain designated as B. subtitles JA-026 was screened and obtained, which had a higher ability to produce those antifungal substances. A series of experiments indicated that the antifungal substances were thermostable and partially sensitive to proteinases K and tryproteinase. When the fermentating broth was fractionated with ammonium sulphate of a final saturation of 70%,the precipitate-enhanced inhibitory activity while the supernatant lost this activity. It appeared that the antifungal substances were likely to be protein.     

Fast neutron radiation inactivation of Bacillus subtilis:Absorbed dose determination

In this paper,fast neutron inactivation effects of Bacillus subtilis were investigated with fission fast neutrons from CFBR-Ⅱreactor of INPC(Institute of Nuclear Physics and Chemistry)and mono-energetic neutrons from the Van de Graaff accelerator at Peking University.The method for determining the absorbed dose in the Bacillus subtilis suspension contained in test tubes is introduced.The absorbed dose,on account of its dependence on the volume and the form of confined state,was determined by combined experiments and Monte Carlo method.Using the calculation results of absorbed dose,the fast neutron inactivation effects on Bacillus subtilis were studied.The survival rates and absorbed dose curve was constructed.     

Inactivation of Bacillus Subtilis by Atomic Oxygen Radical Anion

UAtomic oxygen radical anion （O-） is one of the most active oxygen species, and has extremely high oxidation ability toward small-molecules of hydrocarbons. However, to our knowledge, little is known about the effects of O- on cells of micro-organisms. This work showed that O- could quickly react with the Bacillus subtilis cells and seriously damage the cell walls a s well as their other contents, leading to a fast and irreversible inactivation. SEM micrographs revealed that the cell structures were dramatically destroyed by their exposure to O-. The inactivation efficiencies of B. subtilis depend on the O- intensity, the initial population of cells and the treatment temperature, but not on the pH in the range of our investigation. For a cell concentration of 10^6 cfu/ml, the number of survived cells dropped from 10^6 cfu/ml to 10^3 cfu/ml after about five-minute irradiation by an O- flux in an intensity of 233 nA/cm^2 under a dry argon environment （30 ℃, 1 atm, exposed size： 1.8 cm^2）. The inactivation mechanism of micro-organisms induced by O- is also discussed.     

芽胞杆菌T61的辐射抗性和伽玛射线辐照后蛋白质组的变化分析

采用辐射生存率测定、双向电泳和MALDI-TOF/TOF质谱分析方法,对芽胞杆菌T61的γ-射线辐射抗性和辐射后的蛋白质组学进行分析。结果表明,T61的D10值为4 kGy,远高于辐射敏感的大肠杆菌。在10 kGy γ-射线辐照后,34个蛋白质出现显著变化,包括多种抗氧化酶类、核苷酸合成代谢酶类、能量代谢酶类、转录相关因子、蛋白质合成与更新相关因子。其中,一些抗氧化防御系统重要成员上调表达,暗示出抗氧化保护在芽胞杆菌T61的辐射抗性中发挥重要作用。     

Effects of nitrogen ion irradiation on endoglucanase activity and gene mutation of Bacillus subtilis Bac01

Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2.The mutant strain Bacll with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates.It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU).Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B.subtilis Bac01 and mutant strain Bac11.BLAST comparison result indicated that 10 nucleotides mutated.Bioinformatics methods were used to analyze the two predicted amino acid sequences,and it was found that 5 amino acid residues changed,being all in the cellulose-binding domain of endoglucanase.     

氮离子束注入诱变选育胞外多糖高产菌株

采用氮离子束注入胞外多糖产生菌进行诱变处理来获得胞外多糖高产菌株。氮离子注入过程采用的能量为10 keV,剂量为60×1014–140×1014cm-2。根据其存活率及突变率确定最佳的注入剂量。结果表明:菌株存活率曲线遵循氮离子注入生物效应的"马鞍型曲线",当注入剂量为120×1014cm-2时,获得了最佳的诱变效果。通过筛选和连续5次传代,获得具有良好稳定性的突变株,其多糖产量达到3.29 g/L,较出发菌株提高了19.20%,且发酵周期缩短了6 h。     

A Mutant of Bacillus Subtilis with High-Producing Surfactin by Ion Beam Implantation

In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope （SEM）. The optimum condition of ions implantation, 20 keV of energy and 2.6 × 10^15N^＋/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum （ESI/MS） and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain.