重离子辐照柠檬酸菌株的诱变选育

应用不同剂量重离子束12C+6对黑曲霉出发菌株4﹟进行辐照选育,选育出的高产酸菌株进行发酵试验,应用酸碱中和法测定发酵液中柠檬酸的含量。结果表明:当重离子12C+6的辐照剂量为60 Gy时,正突变率最大,为21%。诱变后的菌株通过酸斑法初筛、摇瓶复筛选育出1株菌株H4002,其发酵液中柠檬酸含量比出发菌株4﹟提高了18%。这说明利用重离子束12C+6辐照处理黑曲霉产生菌可以得到高产柠檬酸突变菌株,其诱变效果显著。     

重离子束诱变选育谷氨酸高产菌株

采用中能12C6+离子束辐照诱变谷氨酸生产菌谷氨酸棒杆菌,结合3种选择性培养基初筛突变菌株,通过摇瓶复筛谷氨酸高产菌株,并进行批次发酵实验。结果表明,经80 Me V/u碳离子束辐照后,受照菌存活率发生显著变化,通过选择性平板初筛、摇瓶复筛选育出1株高产菌株GM006,菌体生长和发酵有较大改进,其发酵最高产酸达121.10 g/L,比出发菌株提高了10.09%,糖酸转化率达60.55%,比原始菌株提高10.09%。该GM006突变株是很有前景的谷氨酸工业生产菌,同时证明重离子束是一种高效的辐射诱变源。     

重离子束辐照选育高产植物乳酸菌

采用重离子束~(12)C~(6+)对乳酸菌出发菌株JTL进行辐照选育。确定吸收剂量300 Gy时最优,在该吸收剂量下,出发菌种的正突变率和致死率均达到最高,分别为34.4%、80%。通过酸斑法初筛和发酵复筛法,选育出高产酸的3株突变菌株(JTL2、JTL3、JTL5),其发酵液中乳酸含量比出发菌株JTL提高了41.29%~49.64%。同时,经过传代实验证实,3株菌株具有良好的遗传稳定性。研究表明,利用重离子束~(12)C~(6+)辐照处理乳酸菌可以得到高产酸的突变菌株,诱变效果显著。     

碳离子束辐照选育截短侧耳素菌原生质体

使用12C6+离子束辐照Clitopilus pinsitus原生质体至不同吸收剂量,运用琼脂柱预筛和96孔板固体发酵选育截短侧耳素高产变异株。结果显示,最佳12C6+离子束吸收剂量为1.5 Gy,在该吸收剂量下正变异率为37.58%。选育出C.pin15I5E和C.pin15II6B两株正变异株,其产量较出发菌株分别提高16.17%和15.47%。表明重离子束辐照原生质体是行之有效的工业微生物诱变育种方法。     

阿魏菇多糖高产菌株筛选的离子束诱变和复合诱变对比研究

为筛选出阿魏菇菌丝体多糖高产菌株，本文进行了阿魏菇多糖高产菌株筛选的离子束诱变和复合诱变对比研究。尝试用打散的阿魏菇菌丝体为靶材，以离子束注入为诱变手段，通过营养缺陷型初筛和摇瓶发酵复筛，获得了2株阿魏菇多糖高产菌株PFPH-1和PFPH-2。其菌丝体多糖产量分别达到551．80mg，L和659．46mg／L，比出发菌株分别提高了46．55％和75．14％。再分别以PFPH．1和PFPH．2为出发菌株，用紫外线和氯化锂进行复合诱变处理，通过高通量初筛和摇瓶发酵复筛，结果发现，菌株1、9和10号比其出发菌株PFPH-1的多糖产量分别减少了27％、38％和37％；菌株17号比其出发菌株PFPH-2的多糖产量减少了28％。在本研究中，紫外线和氯化锂的复合诱变表现出了一定的负效应。     

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%。     

离子束诱变选育高效降解有机磷农药菌株

采用~(12)C~(6+)离子束辐照诱变有机磷降解菌,结合选择性培养基初筛突变菌株,摇瓶复筛获得1株高效降解有机磷菌株LA-1,并对有机磷农药降解进行研究。结果表明:吸收剂量为150 Gy时诱变效果最佳,通过筛选和连续8代培养,获得稳定的突变菌株LA-1,其降解有机磷量为161.71 mg/L,较原始菌株解磷能力提高了2.89倍,当有机磷农药辛硫磷和氧乐果浓度分别为800μg/mL和400μg/mL时,菌株的降解率分别为93.5%和83.6%。突变菌株LA-1对有机磷农药具有良好的降解效果。     

~(12)C~(6+)离子束诱变选育温度耐受螺旋藻高产藻株及其培养条件的优化

以极大螺旋藻(Spirulina maxima)为实验材料,利用不同剂量的~(12)C~(6+)离子束对其进行辐照诱变,采用平板分离和温度选育初筛变异藻株,通过生物量和遗传稳定性复筛温度耐受高产突变株,并优化其培养条件。结果表明,在吸收剂量为600 Gy和800 Gy时对藻株的诱变效果显著,致死率为71.84%和78.47%,筛选出的2株温度耐受突变株,分别是经600 Gy辐照后20℃培养和经800 Gy辐照后35℃培养条件下的螺旋藻突变株Sm04#和Sm21#。经过10次传代培养,生物量分别达到0.54 g/L和0.91 g/L,较对照组提高了11.49%和12.64%,且遗传稳定性良好。培养条件的优化实验表明,Sm04#和Sm21#的最适pH均为9.0,最适光强分别为70μmol/(m~2·s)和80μmol/(m~2·s),最适光暗周期依次为12∶12 h和14∶10 h。进一步对2株突变株在室内扩大培养,蛋白质和多糖含量均高于对照组。研究结果为~(12)C~(6+)离子束辐照诱变螺旋藻藻株的开发和应用提供理论依据。     

80 MeV/u C-12离子诱变选育PHB高产菌株

用80MeV/u12C6+离子对一株积累聚β-羟基丁酸酯(PHB)的芽孢杆菌(BacillusP-9)进行诱变选育,最终获得PHB高产株菌G15,其PHB产量达2.93g/L,与出发菌株相比较,PHB积累量提高了1.5倍。研究结果表明,本试验辐照最佳剂量为15Gy。重离子辐照诱变育种效果显著,具有广阔的发展应用前景。     

低能氮离子注入和紫外线复合诱变选育高产酿酒酵母

通过离子注入联合紫外线辐射诱变选育高产酿酒酵母菌株,根据存活率及突变率确定离子注入的诱变条件为电荷18 ke V,剂量400×10~(14) cm~(-2),紫外线辐射60 s。在该条件下,诱变获得的菌株正突变率和致死率都最高,诱变效果最好。在该条件下进行研究后获得目标菌株SC-N9015,酒精产量从14.65%提升到15.53%。多次传代实验结果显示遗传性状稳定。研究表明,通过低能氮离子注入和紫外线联合诱变选育高产酒精酵母效果显著。     

Mutation induction of Pleurotus ferulae by low-energy N^＋ ion implantation and characters of the selected mutant

In order to obtain Pleurotus ferulae with high temperature tolerance,mycelium mono-cells of wild type strain ACK was treated by nitrogen ion(5～30 keV,1.5×1015～1.5×1016cm-12)implantation,and mutant CGMCC1762 was selected through auxotrophy screening method,which was Lys.VB6 auxotrophy stress with high temperature.We found that during riper period the surface layer mycelium of the mutant was not aging neither grew tegument even above 30℃.The mycelium endurable temperature of the mutant was increased 70℃ compared with that of the wild type strain.The fruiting bodies growth temperature of the mutant was 16-20℃ in daytime and was 6～12℃ at night.The highest growth temperature of fruiting bodies of the mutant Was increased by 5℃ than that of original strain.Through three generation investigation,we found that the mutant CGMCC1762 was stable with high temperature tolerance.     

Flower color mutants induced by carbon ion beam irradiation of geranium(Pelargonium × hortorum,Bailey)

In an attempt to elucidate the biological effects and underlying mutations involving flower color in ornamental plants following carbon ion beam radiation,shoots of geranium were exposed at dosages of 0,10,15,30,and40 Gy,and one flower color mutant was obtained.The morphological characteristics,physiological aspects,and DNA polymorphisms between wild-type and flower color mutants were analyzed.The colors of petal,peduncle,pistil,and stamen of the mutant displayed significant differences compared to those of the wild-type.Compared to the original plants,the total anthocyanin content in the petals of the mutant significantly decreased,resulting in a light pink petal phenotype.DNA polymorphisms detected by random amplified polymorphic DNA analysis showed that the ratio of different bands between the wild-type and mutant reached up to 13.2%.The present study demonstrates that carbon ion beam irradiation is effective in inducing genomic variations,resulting in flower color geranium mutants within a relatively short period of time.Meanwhile,the developed flower-color mutants may be potentially used in future mutational research studies involving ornamental plants.     

Study on Screening of TaGA2ox1 Mutants in Wheat by Ion Beam Irradiation

As a kind of mutagen, ion beam irradiation can create abundant biological mutations. A population of about 2000 lines was generated by irradiating dry wheat seeds of XiaoYan 81 with low-energy nitrogen ion beams. The traits of the plant, such as height, spike type, fertility, stem color and awn length, were investigated. The mutation rate in terms of the plant height in M2 was 2.9%. Eighteen deletion mutants of TaGA2ox1 were obtained. Associate analysis showed that TaGA2ox1 was closely related to the plant height. Most of the TaGA2ox1-deleted mutants were higher than the control, suggesting that the biological function of TaGA2ox1 is similar to its homologues in other plants. These results demonstrate that ion beam irradiation is an efficient tool in the construction of a mutant library for wheat.     

12C6+重离子辐照大葱的生物学效应

用30Gy、90Gy和180Gy 12C6 重离子辐照处理大葱干种子,研究了它对大葱的生物学效应.经过不同剂量12C6 重离子照射过的大葱,幼苗发芽率、株高等表型随着辐照剂量的增大,呈现明显的"抛物线"趋势.适量的12C6 重离子照射(30Gy)能提高大葱发芽率和抗旱、抗倒伏能力,促进生长发育.重离子辐照能有效地诱导大葱根尖细胞微核和染色体畸变形成,180Gy处理的大葱微核率和染色体畸变率最高达到9.09%和10.03%.本实验为大葱的重离子辐照育种打下基础.     

脉冲离子束轰击靶的热效应数值模拟

分析了脉冲离子轰击靶膜和衬底的热效应,在能量较低的情形下,离子轰击处理为靶膜表面热流输入。采用有限元程序,对能量为600keV、束流为12mA的不同束斑半径的脉冲离子流轰击Cu基Ti靶的热传导进行了数值计算,得到了热传导清晰物理图象。     

氯化锂-紫外-离子束复合诱变红霉素高产菌株研究

以红霉素生产菌红色链霉菌为研究对象,探讨了氯化锂、紫外、离子束3种不同诱变方式对红色链霉菌的影响,根据后代的存活率和突变率选定合适的诱变条件：氯化锂的最优诱变浓度12%,紫外的最优诱变时间120s,离子束的最优诱变注量200×1014cm－2,然后将3种方式结合起来进行复合诱变。经复合诱变后筛选获得高产突变株E0317 1 7 26,该菌株摇瓶效价达7126μg/mL,较出发菌株E03提高了203%;经多次传代分离实验表明,该突变株遗传稳定性较好。     

Proton elastic scattering differential cross-sections for C

Carbon depth profiling presents a strong analytical challenge for all the major ion beam analysis (IBA) techniques, with elastic backscattering spectroscopy (EBS) being widely implemented. In the past, the ¹²C(p,p)¹²C reaction has been successfully evaluated for proton beam energies up to 4.5 MeV. Currently, an attempt is being made to extend this evaluation to higher energies, namely up to E_p,lab = 7 MeV. There is a certain lack of available and/or coherent datasets in literature for these relatively high proton beam energies at backward angles, suitable for IBA. Moreover, the few existing datasets are in certain cases discrepant. Thus, in the present work, the differential cross-section of proton elastic scattering on carbon were measured between 140°and 170°, in steps of 10°, for the proton beam energy range between 2.7 and 7 MeV. The experimental results obtained, along with data from literature, were evaluated applying nuclear physics models. The evaluated results were benchmarked using a thick, mirror polished glassy carbon target at different beam energies and detector angles.     

75MeV/u￣(12)C离子Bragg曲线及黑色素瘤细胞失活的测量

用双电离室法测定了ＨＩＲＦＬ提供的７５ＭｅＶ／ｕ１２Ｃ离子经不同厚度降能片后的相对剂量，将降能片厚度等效为组织等效材料一水中的深度，得到了碳离子在水介质中的Ｂｒａｇｇ曲线，与计算的Ｂｒａｇｇ曲线进行了比较。同时测定了离子经不同厚度降能片后对黑色素瘤（Ｂ１６）细胞的失活效应，得到了离子束在不同贯穿深度上的Ｂ１６细胞存活数据。