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.

Bioeffects of Low Energy Ion Beam Implantation:DNA Damage,Mutation and Gene Transter

Low-energy ion beam implantation （10 - 200 keV） has been proved to have a wide range of biological effects and is broadly used in the breeding of crops and micro-organisms.To understand its mechanisms better and facilitate its applications, the developments in the bioeffects of low energy ion beam implantation in the past twenty years are summarized in this paper.

Mutation Breeding of β-carotene Producing Strain B. trispora by Low Energy Ion Implantation

Ion beam bioengineering technology as a new mutation approach has been widely used in the biological breeding field. In this paper the application of low energy nitrogen ion implantation in the β-carotene producing strain, Blakeslea trispora（-） was investigated. The effects of different fermentation conditions on β-carotene production by a high yield strain were examined. Results showed that two β-carotene high yielding strains B.trispora（-） BH3-701 and BH3-728 were screened out and the averaged production of β-carotene was raised by 178.7% and 164.6% respectively after five passages in the shaking flasks. Compared with the original strain, the highest yield strain BH3-701 was potent in accumulating β-carotene, especially in the later stage, and greatly increased production efficiency.

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.

Biological Effects on Fruit Fly by N^+ ion Beam Implantation

Mutation induced by low energy ion beam implantation has been applied widely both in plants and microbes. However, due to the vacuum limitation, such ion implantation into animals was never studied except for silkworm. In this study, Pupae of fruit fly were irradiated with different dosage N+ ions at energy 20 KeV to study the biological effect of ion beam on animal. The results showed a saddle like curve exists between incubate rate and dosage. Damage of pupae by ion beam implantation was observed using scanning electron microscope. Some individuals with incomplete wing were obtained after implantation but no similar character was observed in their offspring. Furthermore, about 5.47% mutants with wide variation appeared in M1 generation. Therefore, ion beam implantation could be widely used for mutation breeding.

Enhancement of Gongronella sp.JG Chitosanase Production by Ion Beam Implantation

Gongronella sp. JG was a fungal strain which expressed extracellular chitosanase of about 800 U/L during its growth in production medium. To improve its enzyme production, low energy N＋ implantation was employed to mutate spores of JG. The implantation condition was optimized and the parameters of 15 keV and 60 × breeding experiments. A mutant designated as SG 2.6 × 10^13 ions/cm^2 were selected for further was obtained. It showed increased chitosanase production （1800 U/L） and shortened cultivation period （from 72 h to 60 h）. Five-generation cultivation of SG indicated that its chitosanase production was stable at about 1800 U/L.

Mutagenic Effects of BM302:GO112 Induced by Low-Energy Ion Beam Implantation

Mutant strains of GO112 and BM302 with a high 2-keto-L-gulonic acid （2KLG） transformation rate induced by ion beam implantation were separately and combinatorially compared with the original strains GO29 and BM80 to study the mutagenic effects of ion beam implantation. Both the sole GOl12 and mixed BM302：GOl12 demonstrated improved SNDH activity and 2KLG yield compared to the original strains. The mutant combinations of BM302：GOl12 showed a longer stationary phase and higher biomass than BM80：GO29. The mutant BM302 exhibited a stronger capacity to maintain a stable pH environment at mixed fermentation with Gluconobacter oxydans （G. oxydans） for 2KLG transformation and facilitated the growth of G. oxydans compared with the original strain BM80. The promotive capacity to L-sorbosone dehydrogenase （L-SNDH） from the supernate of BM302 was 1.6-fold higher than that of BM80. Genes encoded SNDH in GO29 and GOl12 were amplified and sequenced, and mutations including three transitions （CG →TA, CG →TA, GC → AT） and one transversion （AT→ TA） were confirmed from GO29 to GOl12. The corresponding amino acid was changed as Leu →Phe, Arg → Gln and Asn → Lys.

Breeding of High-Yield Salinomycin-Producing Streptomyces albus Strains by Low Energy N^+ Ion Beam Irradiation

[Objective] This study aimed to explore the mutagenesis effects of N＋ ion beam implantation on Streptomyces a/bus and obtain high-yield salinomycin- producing mutant strain. [ Method ] Streptomyces a/bus strain S-11-04 was mutated with different doses of N ＋ implantation. The effects of low energy N ＊ implantation on the survival rate, colony morphology and salinomycin-producing ability were investigated. [ Result] The results showed that low energy N ＋ implantation can efficiently improve the positive mutation rate of Streptomyces albus; 13 mutant strains with high yield of salinomycin were isolated; to be specific, mutant strain N3- 6 has relatively good genetic stability with four continuous generations, and the titres of salinomycin were increased by 41% in the shake-flask culture and 20.5% in mass production compared with the control. [ Conclusion ] N ＋ ion beam irradiation is an effective method to obtain high-yield salinomycin-producing Streptomy- ces albus strain.

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.

Screening of Bioflocculant-Producing Strain by Ion Implantation and Flocculating Characteristics of Bioflocculants

A bioflocculant-producing mutator strain, NIM-192, was screened out through nitrogen ion implanting into F J-7 strain. The results showed that NIM-192 had good genetic stability and high flocculating activity, and the flocculating rate increased by 34.26% than that of the original. Sucrose, complex nitrogen source contained yeast extract, urea and pH 7.0～ 9.0 were chosen as the best carbon source, nitrogen source and initial solution pH for bioflocculant production, respectively. The bioflocculant kept high and stable flocculating activity at alkalinous reaction mixture with a pH beyond 7.0, while the flocculating activity was remarkably reduced when the reaction pH was lower than 7.0. Addition of many cations could obviously increase the flocculating rate, among which Ca^2＋ demonstrated the best effect. The bioflocculant had very strong acid-base stability and thermo-stability.The flocculating rate kept over 86% when pH of the bioflocculant was in a range of 3.0 ～ 12.0, and the change of flocculating activity was not great when heated at 100℃ for 60 rain.

重离子辐照育种对西蓝花幼苗生长及生理特性的影响

西蓝花(Brassica oleracea var.italica)是我国重要的蔬菜作物之一,其种子主要源于进口,亟需开发属于我国的创新型品种。为探究高能重离子束对西蓝花的当代生物学效应,本研究采用碳离子束辐照西蓝花种子,检测其幼苗期的生长指标、抗氧化酶活性、光合指标和叶绿素荧光等参数。结果表明:100~500 Gy的辐照对种子的萌发没有显著影响,600 Gy显著抑制其萌发。100~600 Gy辐照后根长、芽长、苗高、叶面积总体上随剂量增加而降低。碳离子束辐照西蓝花的半致死剂量(Median lethal dose,LD50)为415.89 Gy,使根长减半的剂量为495.12 Gy。辐照后幼苗的超氧化物歧化酶(Superoxide dismutase,SOD)和过氧化物酶(Peroxidase,POD)活性均高于对照,过氧化氢酶(Catalase,CAT)的活性低于对照,400 Gy辐照后丙二醛(Malondialdehyde,MDA)含量显著升高。随吸收剂量的增加光合色素(叶绿素a、叶绿素b和类胡萝卜素)呈现先升高再降低的趋势,最高值出现在300 Gy处。净光合作用、蒸腾速率和气孔导度均与吸收剂量负相关,辐照后非光合淬灭系数显著升高。结果表明,重离子束辐照抑制了西蓝花植株的生长,影响了抗氧化酶活性和光合作用。本研究为西蓝花的重离子束辐照诱变育种提供了基础数据。

我国水稻辐射诱变育种研究进展

水稻(Oryza sativa L.)是主要粮食作物之一,其品种改良对我国农业可持续发展和粮食安全至关重要。辐射诱变技术为改良高产、优质、抗逆的水稻品种提供了有效途径,为种业自主创新作出了重要贡献。本文综述了近二十余年来水稻辐射诱变各类辐射源的应用,选育方法体系,辐射诱发突变的分子机理,水稻产量、抗性、品质等各类表型及相关基因突变体和获得的新品种等领域所取得的研究进展,并对未来使用辐射诱变技术为我国培育产量更高、适应性更强、品质更优的水稻新品种与创制更多用于基因功能研究的新种质等应用前景进行了展望。

低能离子注入在Vc高产菌株选育中的应用

对低能离子注入 Ｖｃ 生产菌的诱变效应进行研究。结果表明，离子注入 Ｖｃ 生产菌能获得较高的突变率和较广 的突变谱。比较了 Ｈ＋ 、 Ｎ＋ 、 Ａｒ＋ 注入 Ｖｃ 生产菌的差异，确定了最佳诱变剂量。由此筛选出４ 株 Ｖｃ高产菌，其糖酸克分子转化率达 ９４％ 。目前已通过工业生产试验，并为企业带来显著的经济效益，同时也为工业微生物的选育提供了一条全新的途径。

工业微生物物理诱变育种技术的新进展

物理诱变技术是当今工业微生物育种中最重要、最有效的技术之一。传统的物理诱变技术主要有紫外线、X射线、γ射线诱变等,它们已在包括青霉素、"-淀粉酶等几乎所有的工业微生物菌种的诱变选育中发挥了巨大的作用。多数菌株在多次重复使用传统诱变源时往往出现抗性饱和的现象。太空环境、离子束、激光等是20世纪70～80年代逐渐兴起的新型诱变技术,因它们具有诱变谱广和在一定程度上能克服菌株对传统诱变源的抗性饱和等优点,而广受工业微生物育种工作者的欢迎。现就空间、离子束、激光等诱变育种技术的作用特点、诱变机理、应用及前景进行阐述。

观赏植物诱变育种的研究现状和展望

本文综述了观赏植物辐射诱变育种的研究现状,并对花卉辐照诱变的手段、方法、处理材料和适宜辐照剂量、辐照机理与方法及应用作了总结,同时对观赏植物辐射诱变育种存在的问题及发展方向进行了探讨。

离子束用于诱变育种的研究进展

本文对离子注入的特点、诱变的机理、引起的生物学效应以及与传统辐射诱变效应异同进行了概述。对离子束生物技术与传统辐射诱变技术在作物育种中的应用做了比较分析 ,展望了离子束的应用前景。

原生质体诱变在工业微生物育种中的应用进展

介绍了原生质体诱变技术,综述了其在酶制剂、抗生素、氨基酸、维生素、杀虫剂等高产菌种选育中的应用进展;对该技术与离子束技术、空间技术的结合在微生物菌种选育中的应用前景进行了展望。

离子注入在小麦诱变育种上的应用研究初报

采用不同剂量不同能量的离子处理小麦新品种豫麦 39和优质小麦品种豫麦 47、陕优 2 2 5、兰考 90 ( 6 ) - 4,PH82 - 2 - 2和一些高代品系 ,发现出苗率、株高等性状的变异相差很大 .结果证明 ,用 30keV ,3× 10 17N+·cm-2 离子注入豫麦 39效果最佳 .M1代株高比Ck(未处理的本品种 )降低 12～ 2 9cm .M2 代共选 18株 ,株高 6 7～ 83cm ,平均 76 8cm ,克服了豫麦 39植株偏高的缺点 。

植物诱变新技术及其在水稻育种上的应用

简要综述了石蜡油-EMS花粉诱变、离子束注入、花粉辐照和空间诱变新技术的诱变机理、生物学效应及其在水稻育种上的应用。

N^+离子注入阿维拉霉素产生菌诱变效应的研究

选用低能(30keV)N+离子注入阿维拉霉素产生菌SV-56,研究其诱变效应。试验结果表明:SV-56菌株存活率曲线是典型的“马鞍型”剂量-效应曲线,“马鞍型”区域内具有高的正突变率(20．9％-26．2％)。通过5×1015cm-2N+注入诱变处理、链霉素抗性筛选,最终获得一株稳定性良好、阿维拉霉素产量稳定在79．6-82．9 mg·L-1之间、较出发菌株提高41．4％-47．2％的突变株SVN-116。