Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbosedehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase(SDH) of Gluconobacter oxydans in the 2-keto-L-gu...Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbosedehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase(SDH) of Gluconobacter oxydans in the 2-keto-L-gulonic acid (2KLG) fermentation from L-sorboseby the mixed culture of B.megaterium BM302 and G.oxydans.The SAP purified by threechromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of5.21 units/mg protein.The molecular weight of the purified SAP was about 58 kDa.The SDHaccelerative activity of SAP at pH 7 and 50℃ was the highest.Additionally,it retained 60%activity at a pH range of 6.5～10 and was stable at 20℃～60℃.After 0.32-unit SAP was addedto the single cultured G.oxydans strains,the SDH activity was apparently accelerated and the2KLG yield of GO29,GO112,G0 and G113 was enhanced 2.1,3.3,3.5 and 2.9 folds respectivelyover that of the strains without the addition of SAP.展开更多
As a new mutagenetic method,low-energy ion implantation has been used widelyin many research areas in recent years.In order to obtain some industrial strains with highxylanase yield,the wild type strain Aspergillus ni...As a new mutagenetic method,low-energy ion implantation has been used widelyin many research areas in recent years.In order to obtain some industrial strains with highxylanase yield,the wild type strain Aspergillus niger A3 was mutated by means of nitrogenions implantation(10 keV,2.6×10^(14)～1.56×10^(15)ions/cm^2)and a mutant N212 was isolatedsubsequently.However,it was found that the initial screening means of the high-yielding xylanasestrains such as transparent halos was unfit for first screening.Compared with that of the wildtype strain,xylanase production of the mutant N212 was increased from 320 IU/ml to 610 IU/ml,and the optimum fermentation temperature was increased from 28℃ to 30℃.展开更多
Retrotransposon-like elements are major constituents of most eukaryotic genomes.For example,they account for roughly 90% of the wheat (Triticum aestivum) genome.Previ-ous study on a wheat strain treated by low-energy ...Retrotransposon-like elements are major constituents of most eukaryotic genomes.For example,they account for roughly 90% of the wheat (Triticum aestivum) genome.Previ-ous study on a wheat strain treated by low-energy N+ ions indicated the variations in AFLP(Amplified Fragment Length Polymorphism ) markers.One such variation was caused bythe re-activation of Tyl-copia-like retrotransposons,implying that the mutagenic effects of low-energy ions might work through elevated activation of retrotransposons.In this paper an ex-pression profile of Tyl-copia-like retrotransposons in wheat treated by low-energy N+ ions isreported.The reverse transcriptase (RT) domains of these retrotransposons were amplified byreverse-transcriptional polymerase chain reaction (RT-PCR) and sequentially cloned.42 and 65clones were obtained from the treated (CL) and control materials (CK),respectively.Sequenceanalysis of each clone was performed by software.Phylogeny and classification were calculatedresponding to the sequences of the RT domains.All the results show that there is much differencein the RT domain between the control sample and the treated sample.Especially,the RT domainsfrom the treated group encode significantly more functional ORF (open reading frames) than thosefrom the control sample.This observation suggests that the treated sample has higher activationof retrotransposons,possibly as a consequence of low-energy ion beam irradiation.It also suggeststhat retrotransposons in the two groups impact the host gene expression in two different ways andcarry out different functions in wheat cells.展开更多
In order to generate a mutant of Bacillus subtilis with enhanced surface activitythrough low energy nitrogen ion beam implantation, the effects of energy and dose of ions im-planted were studied. The morphological cha...In order to generate a mutant of Bacillus subtilis with enhanced surface activitythrough low energy nitrogen ion beam implantation, the effects of energy and dose of ions im-planted were studied. The morphological changes in the bacteria were observed by scanningelectron microscope (SEM). The optimum condition of ions implantation, 20 keV of energy and2.6×10^(15)N^+/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activ-ity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wildstrain. The microbial growth and biosurfactant production of both the mutant and the wild strainwere compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was de-termined to be a complex of surfactin family through analysis of electrospray ionization massspectrum (ESI/MS) and there was an interesting finding that after the ion beam implantation theintensities of the components were different from the wild type strain.展开更多
The effect of absence of lipoxygenase isoenzyme(LOX)on storage stability wasinvestigated.Rice mutant 1297 without lipoxygenase isoenzyme-1(LOX-1)or lipoxygenaseisoenzyme-2(LOX-2)generated by ion beam irradiation from ...The effect of absence of lipoxygenase isoenzyme(LOX)on storage stability wasinvestigated.Rice mutant 1297 without lipoxygenase isoenzyme-1(LOX-1)or lipoxygenaseisoenzyme-2(LOX-2)generated by ion beam irradiation from Wanjian2090 and reversion mutantRM1297 with LOX-1 and LOX-2 were subjected to an accelerated-aging experiment.Shanyou63(with LOX-1 and LOX-2)served as control.Results showed that the germination and dehydro-genase activity decreased while the electrical conductivity and free fatty acid content increased inall varieties with accelerated aging.In 1297 that lacked LOX-1 and 2,there were slight changes ingermination,dehydrogenase activity,membrane permeability and free fatty acid content duringthe thirty-day accelerated-aging experiment.But in varieties with LOX-1 and LOX-2,significantchanges were observed,suggesting that LOX-1,2 might be a definite factor which influenced seedlifespan.This study also indicates that ion beam irradiation may be used as mutagen to generatemutant and reversion mutants for biological study and could become a new direction in ion beamapplication.展开更多
Ever since the low energy N+ ion beam has been accepted that the mutation effectsof ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences basedon naked DNA irradiation in support of a...Ever since the low energy N+ ion beam has been accepted that the mutation effectsof ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences basedon naked DNA irradiation in support of a mutation spectrum appears to be consistent, but directproof of such results in vivo are limited. Using mutS, dam and/or dcm defective Eschericha colimutator strains, an preliminary experimental system on induction of in vivo mutation spectra oflow energy N+ ion beam has been established in this study. It was observed that the mutationrates of rifampicin resistance induced by N+ implantation were quite high, ranging from 9.2 ×10-8 to 4.9 × 10-5 at the dosage of 5.2 × 1014 ions/cm2. Strains all had more than 90-fold highermutation rate than its spontaneous mutation rate determined by this method. It reveals thatbase substitutions involve in induction of mutation of low energy nitrogen ion beam implantation.The mutation rates of mutator strains were nearly 500-fold (GM2929), 400-fold (GM5864) and6-fold larger than that of AB1157. The GM2929 and GM5864 both lose the ability of repair DNAmismatch damage by virtue of both dam and dcm pathways defective (GM2929) or failing toassemble the repair complex (GM5864) respectively. It may explain the both strains had a similarhigher mutation rate than GM124 did. It indicated that DNA cytosine methylase might play animportant role in mismatch repair of DNA damage induced by N+ implantation. The furtherrelated research were also discussed.展开更多
To obtain thermotolerant mutants of G. oxydans, which can enhance the transformation rate of L-sorbose to 2-Keto-L-gulonate (2-KLG) at 33℃ in a two-step process of vitamin C manufacture, ion beam was used as a mutati...To obtain thermotolerant mutants of G. oxydans, which can enhance the transformation rate of L-sorbose to 2-Keto-L-gulonate (2-KLG) at 33℃ in a two-step process of vitamin C manufacture, ion beam was used as a mutation source. Gluconobacter oxydans GO and Bacillus megaterium B0 were used in this study. The original strain Gluconobacter oxydans GO was mutated by the heavy ion implantation facility at the Institute of Plasma Physics, Chinese Academy of Sciences. Several mutants including Gluconobacter oxydans GI13 were isolated and cocultured with Bacillus megaterium B0 at 33℃ in shaking flasks. The average transformation rate of the new mixed strain GI13-B0 in per gram-molecule reached 94.4% after seven passages in shaking flasks, which was increased by 7% when compared with the original mixed strain G0-B0 (Gluconobacter oxydans G0 and Bacillus megaterium B0). Moreover, the transformation rate of I13B0 was stable at 94% at temperatures ranging from 25℃ to 33℃, which would be of much value in reducing energy consumption in the manufacture of L-ascorbic acid, especially in the season of summer. To clarify some mechanism of the mutation, the specific activities of L-sorbose dehydrogenase in both G0 and GI13 were estimated.展开更多
In order to obtain an industrial strain with a higher L(+)-lactic acid yield, the strain Rhizopus oryzae RF3608 was mutated by means of nitrogen ion beam implantation and the mutant strain RLC41-6 was isolated. Under ...In order to obtain an industrial strain with a higher L(+)-lactic acid yield, the strain Rhizopus oryzae RF3608 was mutated by means of nitrogen ion beam implantation and the mutant strain RLC41-6 was isolated. Under optimal conditions the yield of L(+)-lactic acid produced in a shake-flask reached 133 g/L～137 g/L after 36 h cultivation, indicating that the It was almost a 115% increase in lactic acid production compared with the original strain RF3608.展开更多
Low-energy ion beam implantation (10～200 keV) has been proved to have a widerange of biological effects and is broadly used in the breeding of crops and micro-organisms.Tounderstand its mechanisms better and facilita...Low-energy ion beam implantation (10～200 keV) has been proved to have a widerange of biological effects and is broadly used in the breeding of crops and micro-organisms.Tounderstand its mechanisms better and facilitate its applications,the developments in the bioeffectsof low energy ion beam implantation in the past twenty years are summarized in this paper.展开更多
Immobilized Rhizopus oryzae culturing may be a solution to the inhibited productionof L(+)-lactic acid in submerged fermentation,which is caused by aggregated mycelia floc.In thepresent study,a R.oryzae mutant (RL6041...Immobilized Rhizopus oryzae culturing may be a solution to the inhibited productionof L(+)-lactic acid in submerged fermentation,which is caused by aggregated mycelia floc.In thepresent study,a R.oryzae mutant (RL6041) with a 90% conversion rate of glucose into L-lacticacid was obtained by N^+ implantation under the optimized conditions of a beam energy of 15 keVand a dose of 2.6×10^(15) ions/cm^2.Using polyurethane foam as the immobilization matrix,the optimal L-lactic acid production conditions were determined as 4 mm polyurethane foam,150 r/min,50 g/L～80 g/L of initial glucose,38℃ and pH 6.0.15-cycle repeated productionsof L-lactic acid by immobilized RL6041 were performed under the optimized culturing conditionsand over 80% of the glucose was converted into L-lactic acid in 30 hours on average.The resultsshow that immobilized RL6041 is a promising candidate for continuous L-lactic acid production.展开更多
In this paper, the following contents including the original receptor EI213 and other two control materials, RAPD polymorphism, photosynthetic efficiency, and the number of vascular bundles of the first internodes bel...In this paper, the following contents including the original receptor EI213 and other two control materials, RAPD polymorphism, photosynthetic efficiency, and the number of vascular bundles of the first internodes below the peduncle have been studied for the eight F7 transgenic lines obtained from ion beam implantation. The results showed that there was a significant variation in genomes of maize-rice line, compared with the receptor EI213, after the total exogenous maize DNA was introduced into EI213. The number of the vascular bundles of maize-rice progeny's lines was obviously much larger than those of the original receptor EI213 and other two controls GER-3 and MH63, and along with the photosynthetic efficiency of maize-rice progeny's lines being gone up. Moreover, the parenchyma cells around the vascular bundles of the transgenic lines became much larger in number and in size than those around the controls. All these indicated that the maize-rice progeny's lines are really different from and superior to the receptor and the controls. It is a novel and useful way to apply ion beam implantation in transferring DNA from C4 plant maize into C3 plant rice.展开更多
Calluses of two autotetraploid rice(DPR(4) and Zijing(4)) were implanted with 30 KeV N+beams at doses ranging from1.0×1015to 9.0×1015ions cm-2.The differentiation rates of calluses,the concentration of malon...Calluses of two autotetraploid rice(DPR(4) and Zijing(4)) were implanted with 30 KeV N+beams at doses ranging from1.0×1015to 9.0×1015ions cm-2.The differentiation rates of calluses,the concentration of malondialdehyde(MDA),the activities of superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD),and the change of esterase(EST) spectrum were measured and analyzed on the calluses stage.The results showed that differentiation rates of calluses under 3.0×1015ions cm-2((46.12±2.01)%) were higher than the other treatment groups in DPR(4),and those of Zijing(4) were similar under the doses of 1.0×1015,3.0×1015and 5.0×1015ions cm-2((40.55±2.74),(37.77±3.04) and(34.56±2.65)%) and were higher than that of 7.0×1015and 9.0×1015ions cm-2.When the doses were 3.0×1015and 5.0×1015ions cm-2,the activities of SOD,POD and CAT were notably enhanced,and the accumulation of MDA content was markedly alleviated in the implanted calluses of two materials,as well as the activity of EST was increased by the additional isforms DPR(4).Whereas the anti-oxidative systems and enzymes spectrum of EST were destroyed seriously,the accumulation of MDA was significantly aggravated,also the differentiation rate of calluses reduced sharply and almost closed to zero when the implantation doses were 7.0×1015and 9.0×1015ions cm-2.It suggested that the proper dose of ion implantation effectively maintained the normal membrane structure and metabolism,and it would be also a feasible approach for autotetraploid rice to improve its genetic characteristics at calluses stage.Additionally,the differences of the radiation resistance between DPR(4) and Zijing(4) could be related to the different genotypes.展开更多
Gongronella sp.JG was a fungal strain which expressed extracellular chitosanase ofabout 800 U/L during its growth in production medium.To improve its enzyme production,lowenergy N^+implantation was employed to mutate ...Gongronella sp.JG was a fungal strain which expressed extracellular chitosanase ofabout 800 U/L during its growth in production medium.To improve its enzyme production,lowenergy N^+implantation was employed to mutate spores of JG.The implantation condition wasoptimized and the parameters of 15 keV and 60×2.6×10^(13)ions/cm^2 were selected for furtherbreeding experiments.A mutant designated as SG was obtained.It showed increased chitosanaseproduction(1800 U/L)and shortened cultivation period(from 72 h to 60 h).Five-generationcultivation of SG indicated that its chitosanase production was stable at about 1800 U/L.展开更多
The whole DNA of soybean was implanted into four varieties of wheat of Zhougyu 5,Huaiyin 9628,Wenyou 1,Jimai 5 respectively via ion-beam mediation.There were 5 plants obtained whose protein content was higher than 18....The whole DNA of soybean was implanted into four varieties of wheat of Zhougyu 5,Huaiyin 9628,Wenyou 1,Jimai 5 respectively via ion-beam mediation.There were 5 plants obtained whose protein content was higher than 18.5%,the highest one was 21.44%,There were 3 plants obtained whose protein content was lower than 11.5%,the lowest one was 10.96%.We can see that the whole DNA of soybean transformed into wheat via ion beam implantation can induce the increase in wheat protein content dramatically.The result also shows that the transformation efficiency of different gene types of wheat receptor varies greatly that the implanting time has a certain effect on the efficiency of transformation.展开更多
Mutant strains of GOl12 and BM302 with a high 2-keto-L-gulonic acid (2KLG)transformation rate induced by ion beam implantation were separately and combinatorially com-pared with the original strains GO29 and BM80 to s...Mutant strains of GOl12 and BM302 with a high 2-keto-L-gulonic acid (2KLG)transformation rate induced by ion beam implantation were separately and combinatorially com-pared with the original strains GO29 and BM80 to study the mutagenic effects of ion beam implan-tation.Both the sole GO112 and mixed BM302:GO112 demonstrated improved SNDH activityand 2KLG yield compared to the original strains.The mutant combinations of BM302:GO112showed a longer stationary phase and higher biomass than BM80:GO29.The mutant BM302exhibited a stronger capacity to maintain a stable pH environment at mixed fermentation withGluconobacter 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 dehy-drogenase (L-SNDH) from the supernate of BM302 was 1.6-fold higher than that of BM80.Genesencoded SNDH in GO29 and GOl12 were amplified and sequenced,and mutations including threetransitions (CG→TA,CG→TA,GC→AT) and one transversion (AT→TA) were confirmedfrom GO29 to GO112.The corresponding amino acid was changed as Leu→Phe,Arg→Glnand Asn→Lys.展开更多
Vacuum treatment and ion-beam bombardment are two major processes in the low energy ion-beam implantation. To accurately study the contributions of these two major factors to the bioeffects separately, the M_1 generat...Vacuum treatment and ion-beam bombardment are two major processes in the low energy ion-beam implantation. To accurately study the contributions of these two major factors to the bioeffects separately, the M_1 generation variation of Arabidopsis thaliana with ion-beam implantation and vacuum treatment were compared through a series of key plant development parameters including morphological observation, biochemical assay and RAPD (random amplified polymorphic DNA) analysis. The results showed that ion-beam implantation had obvious effect on almost all of these parameters, and the vacuum treatment had some impacts on several morphological parameters such as the bolting time and the length of the primary stem. Taking the results together, the indication is that vacuum treatment has some slight contributions to the bioeffects of ion-beam implantation while ion-beam bombardment itself is the major creator of the bioeffects.展开更多
We have developed a large number of exocrine glands on liquorice leaves and facilitated polysaccharide secretion. Liquorice polysaccharide possesses stronger bound water affinity to gaseous water compared with sucrose...We have developed a large number of exocrine glands on liquorice leaves and facilitated polysaccharide secretion. Liquorice polysaccharide possesses stronger bound water affinity to gaseous water compared with sucrose and glucose. Our results show that the bound water affinity of liquorice polysaccharide to gaseous water is 49.75% higher than glucose (p<0.01). With N^+ implantation (total dosage of 4.68×10^(16) ions/cm^2 and energy of 20 keV) into dry liquorice seeds, both the bound water affinity to gaseous water and the bound water content of dry liquorice leaf can be significantly increased 30.24% (p<0.01) and 36.51% (p<0.01) respectively compared with the sham-irradiated seeds. Meanwhile, with these parameters chosen for N^+ implantation into dry liquorice seeds, the leaf polysaccharide content under water stress (ψ_w=-1.5 MPa) can increase significantly (p<0.05) and the plant growth can also improve significantly (p<0.05).展开更多
Single-particle microbeam as a powerful tool can open a research field to find answers to many enigmas in radiobiology. A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioen...Single-particle microbeam as a powerful tool can open a research field to find answers to many enigmas in radiobiology. A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS), China. However there has been less research activities in this field concerning the original process of the interaction between low-energy ions and complicated, organisms. To address this challenge, an in situ multi-dimensional quantitative fluorescence microscopy system combined with the CAS-LIBB single-particle microbeam Ⅱ endstation is proposed. In this article, the rationale, logistics and development of many aspects of the proposed system are discussed.展开更多
Single particle microbeam(SPM)is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful...Single particle microbeam(SPM)is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism.This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.展开更多
The proposed multi-dimensional quantitative fluorescence microscopy for the CAS-LIBB single-particle microbeam Ⅱ endstation is a CCD-based imaging system. We systematicallyanalyse the theoretical and the practical co...The proposed multi-dimensional quantitative fluorescence microscopy for the CAS-LIBB single-particle microbeam Ⅱ endstation is a CCD-based imaging system. We systematicallyanalyse the theoretical and the practical considerations pertinent to choosing the right CCDcamera and unveiling the principles underlying multifarious parameters. Therefore, this analysiscan be a valuable tool in scrutinizing each parameter and clarifying proper usage of a scientificCCD camera.展开更多
基金the General Program of National Science Foundation of China(No.10375066)
文摘Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbosedehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase(SDH) of Gluconobacter oxydans in the 2-keto-L-gulonic acid (2KLG) fermentation from L-sorboseby the mixed culture of B.megaterium BM302 and G.oxydans.The SAP purified by threechromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of5.21 units/mg protein.The molecular weight of the purified SAP was about 58 kDa.The SDHaccelerative activity of SAP at pH 7 and 50℃ was the highest.Additionally,it retained 60%activity at a pH range of 6.5～10 and was stable at 20℃～60℃.After 0.32-unit SAP was addedto the single cultured G.oxydans strains,the SDH activity was apparently accelerated and the2KLG yield of GO29,GO112,G0 and G113 was enhanced 2.1,3.3,3.5 and 2.9 folds respectivelyover that of the strains without the addition of SAP.
基金the National Key Technologies R & D Program of China during the 10th Five-Year Plan(No.2001BA302B)
文摘As a new mutagenetic method,low-energy ion implantation has been used widelyin many research areas in recent years.In order to obtain some industrial strains with highxylanase yield,the wild type strain Aspergillus niger A3 was mutated by means of nitrogenions implantation(10 keV,2.6×10^(14)～1.56×10^(15)ions/cm^2)and a mutant N212 was isolatedsubsequently.However,it was found that the initial screening means of the high-yielding xylanasestrains such as transparent halos was unfit for first screening.Compared with that of the wildtype strain,xylanase production of the mutant N212 was increased from 320 IU/ml to 610 IU/ml,and the optimum fermentation temperature was increased from 28℃ to 30℃.
基金supported by National Natural Science Foundation of China (No.10505018)Natural Science Foundation of Henan Province (No.511030400)
文摘Retrotransposon-like elements are major constituents of most eukaryotic genomes.For example,they account for roughly 90% of the wheat (Triticum aestivum) genome.Previ-ous study on a wheat strain treated by low-energy N+ ions indicated the variations in AFLP(Amplified Fragment Length Polymorphism ) markers.One such variation was caused bythe re-activation of Tyl-copia-like retrotransposons,implying that the mutagenic effects of low-energy ions might work through elevated activation of retrotransposons.In this paper an ex-pression profile of Tyl-copia-like retrotransposons in wheat treated by low-energy N+ ions isreported.The reverse transcriptase (RT) domains of these retrotransposons were amplified byreverse-transcriptional polymerase chain reaction (RT-PCR) and sequentially cloned.42 and 65clones were obtained from the treated (CL) and control materials (CK),respectively.Sequenceanalysis of each clone was performed by software.Phylogeny and classification were calculatedresponding to the sequences of the RT domains.All the results show that there is much differencein the RT domain between the control sample and the treated sample.Especially,the RT domainsfrom the treated group encode significantly more functional ORF (open reading frames) than thosefrom the control sample.This observation suggests that the treated sample has higher activationof retrotransposons,possibly as a consequence of low-energy ion beam irradiation.It also suggeststhat retrotransposons in the two groups impact the host gene expression in two different ways andcarry out different functions in wheat cells.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No.KSCX2-SW-324)
文摘In order to generate a mutant of Bacillus subtilis with enhanced surface activitythrough low energy nitrogen ion beam implantation, the effects of energy and dose of ions im-planted were studied. The morphological changes in the bacteria were observed by scanningelectron microscope (SEM). The optimum condition of ions implantation, 20 keV of energy and2.6×10^(15)N^+/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activ-ity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wildstrain. The microbial growth and biosurfactant production of both the mutant and the wild strainwere compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was de-termined to be a complex of surfactin family through analysis of electrospray ionization massspectrum (ESI/MS) and there was an interesting finding that after the ion beam implantation theintensities of the components were different from the wild type strain.
基金supported by the Knowledge Innovative Program of the Chinese Academy of Sciences(No.KSCX-SW-32)
文摘The effect of absence of lipoxygenase isoenzyme(LOX)on storage stability wasinvestigated.Rice mutant 1297 without lipoxygenase isoenzyme-1(LOX-1)or lipoxygenaseisoenzyme-2(LOX-2)generated by ion beam irradiation from Wanjian2090 and reversion mutantRM1297 with LOX-1 and LOX-2 were subjected to an accelerated-aging experiment.Shanyou63(with LOX-1 and LOX-2)served as control.Results showed that the germination and dehydro-genase activity decreased while the electrical conductivity and free fatty acid content increased inall varieties with accelerated aging.In 1297 that lacked LOX-1 and 2,there were slight changes ingermination,dehydrogenase activity,membrane permeability and free fatty acid content duringthe thirty-day accelerated-aging experiment.But in varieties with LOX-1 and LOX-2,significantchanges were observed,suggesting that LOX-1,2 might be a definite factor which influenced seedlifespan.This study also indicates that ion beam irradiation may be used as mutagen to generatemutant and reversion mutants for biological study and could become a new direction in ion beamapplication.
基金The project supported by the National Nature Science Foundation of China (No. 19890300)
文摘Ever since the low energy N+ ion beam has been accepted that the mutation effectsof ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences basedon naked DNA irradiation in support of a mutation spectrum appears to be consistent, but directproof of such results in vivo are limited. Using mutS, dam and/or dcm defective Eschericha colimutator strains, an preliminary experimental system on induction of in vivo mutation spectra oflow energy N+ ion beam has been established in this study. It was observed that the mutationrates of rifampicin resistance induced by N+ implantation were quite high, ranging from 9.2 ×10-8 to 4.9 × 10-5 at the dosage of 5.2 × 1014 ions/cm2. Strains all had more than 90-fold highermutation rate than its spontaneous mutation rate determined by this method. It reveals thatbase substitutions involve in induction of mutation of low energy nitrogen ion beam implantation.The mutation rates of mutator strains were nearly 500-fold (GM2929), 400-fold (GM5864) and6-fold larger than that of AB1157. The GM2929 and GM5864 both lose the ability of repair DNAmismatch damage by virtue of both dam and dcm pathways defective (GM2929) or failing toassemble the repair complex (GM5864) respectively. It may explain the both strains had a similarhigher mutation rate than GM124 did. It indicated that DNA cytosine methylase might play animportant role in mismatch repair of DNA damage induced by N+ implantation. The furtherrelated research were also discussed.
基金supported by the National Major Technologies R&D Program of China during the 10th Five-Year Plan Period (No. 2001BA302B)
文摘To obtain thermotolerant mutants of G. oxydans, which can enhance the transformation rate of L-sorbose to 2-Keto-L-gulonate (2-KLG) at 33℃ in a two-step process of vitamin C manufacture, ion beam was used as a mutation source. Gluconobacter oxydans GO and Bacillus megaterium B0 were used in this study. The original strain Gluconobacter oxydans GO was mutated by the heavy ion implantation facility at the Institute of Plasma Physics, Chinese Academy of Sciences. Several mutants including Gluconobacter oxydans GI13 were isolated and cocultured with Bacillus megaterium B0 at 33℃ in shaking flasks. The average transformation rate of the new mixed strain GI13-B0 in per gram-molecule reached 94.4% after seven passages in shaking flasks, which was increased by 7% when compared with the original mixed strain G0-B0 (Gluconobacter oxydans G0 and Bacillus megaterium B0). Moreover, the transformation rate of I13B0 was stable at 94% at temperatures ranging from 25℃ to 33℃, which would be of much value in reducing energy consumption in the manufacture of L-ascorbic acid, especially in the season of summer. To clarify some mechanism of the mutation, the specific activities of L-sorbose dehydrogenase in both G0 and GI13 were estimated.
基金The project supported by the Tenth Five-Year Plan Period National Key Technologies R & D Program of China (under GrantNo. 2001BA302B)
文摘In order to obtain an industrial strain with a higher L(+)-lactic acid yield, the strain Rhizopus oryzae RF3608 was mutated by means of nitrogen ion beam implantation and the mutant strain RLC41-6 was isolated. Under optimal conditions the yield of L(+)-lactic acid produced in a shake-flask reached 133 g/L～137 g/L after 36 h cultivation, indicating that the It was almost a 115% increase in lactic acid production compared with the original strain RF3608.
文摘Low-energy ion beam implantation (10～200 keV) has been proved to have a widerange of biological effects and is broadly used in the breeding of crops and micro-organisms.Tounderstand its mechanisms better and facilitate its applications,the developments in the bioeffectsof low energy ion beam implantation in the past twenty years are summarized in this paper.
基金Key 863 fund of China(No.2006AA020102)the Key Technologies Research and Development Programme of Anhui Province(07010202076)
文摘Immobilized Rhizopus oryzae culturing may be a solution to the inhibited productionof L(+)-lactic acid in submerged fermentation,which is caused by aggregated mycelia floc.In thepresent study,a R.oryzae mutant (RL6041) with a 90% conversion rate of glucose into L-lacticacid was obtained by N^+ implantation under the optimized conditions of a beam energy of 15 keVand a dose of 2.6×10^(15) ions/cm^2.Using polyurethane foam as the immobilization matrix,the optimal L-lactic acid production conditions were determined as 4 mm polyurethane foam,150 r/min,50 g/L～80 g/L of initial glucose,38℃ and pH 6.0.15-cycle repeated productionsof L-lactic acid by immobilized RL6041 were performed under the optimized culturing conditionsand over 80% of the glucose was converted into L-lactic acid in 30 hours on average.The resultsshow that immobilized RL6041 is a promising candidate for continuous L-lactic acid production.
基金The project supported by National Key Programme of China (No. 2001BA302B-03) National Natural Science Foundation of China (No. 30370863)
文摘In this paper, the following contents including the original receptor EI213 and other two control materials, RAPD polymorphism, photosynthetic efficiency, and the number of vascular bundles of the first internodes below the peduncle have been studied for the eight F7 transgenic lines obtained from ion beam implantation. The results showed that there was a significant variation in genomes of maize-rice line, compared with the receptor EI213, after the total exogenous maize DNA was introduced into EI213. The number of the vascular bundles of maize-rice progeny's lines was obviously much larger than those of the original receptor EI213 and other two controls GER-3 and MH63, and along with the photosynthetic efficiency of maize-rice progeny's lines being gone up. Moreover, the parenchyma cells around the vascular bundles of the transgenic lines became much larger in number and in size than those around the controls. All these indicated that the maize-rice progeny's lines are really different from and superior to the receptor and the controls. It is a novel and useful way to apply ion beam implantation in transferring DNA from C4 plant maize into C3 plant rice.
基金financially supported by the National Natural Science Foundation of China(10505018)the Natural Science Foundation of Henan ProvinceChina(091100110401)
文摘Calluses of two autotetraploid rice(DPR(4) and Zijing(4)) were implanted with 30 KeV N+beams at doses ranging from1.0×1015to 9.0×1015ions cm-2.The differentiation rates of calluses,the concentration of malondialdehyde(MDA),the activities of superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD),and the change of esterase(EST) spectrum were measured and analyzed on the calluses stage.The results showed that differentiation rates of calluses under 3.0×1015ions cm-2((46.12±2.01)%) were higher than the other treatment groups in DPR(4),and those of Zijing(4) were similar under the doses of 1.0×1015,3.0×1015and 5.0×1015ions cm-2((40.55±2.74),(37.77±3.04) and(34.56±2.65)%) and were higher than that of 7.0×1015and 9.0×1015ions cm-2.When the doses were 3.0×1015and 5.0×1015ions cm-2,the activities of SOD,POD and CAT were notably enhanced,and the accumulation of MDA content was markedly alleviated in the implanted calluses of two materials,as well as the activity of EST was increased by the additional isforms DPR(4).Whereas the anti-oxidative systems and enzymes spectrum of EST were destroyed seriously,the accumulation of MDA was significantly aggravated,also the differentiation rate of calluses reduced sharply and almost closed to zero when the implantation doses were 7.0×1015and 9.0×1015ions cm-2.It suggested that the proper dose of ion implantation effectively maintained the normal membrane structure and metabolism,and it would be also a feasible approach for autotetraploid rice to improve its genetic characteristics at calluses stage.Additionally,the differences of the radiation resistance between DPR(4) and Zijing(4) could be related to the different genotypes.
基金the National Natural Science Foundation of China(No.10605027).
文摘Gongronella sp.JG was a fungal strain which expressed extracellular chitosanase ofabout 800 U/L during its growth in production medium.To improve its enzyme production,lowenergy N^+implantation was employed to mutate spores of JG.The implantation condition wasoptimized and the parameters of 15 keV and 60×2.6×10^(13)ions/cm^2 were selected for furtherbreeding experiments.A mutant designated as SG was obtained.It showed increased chitosanaseproduction(1800 U/L)and shortened cultivation period(from 72 h to 60 h).Five-generationcultivation of SG indicated that its chitosanase production was stable at about 1800 U/L.
文摘The whole DNA of soybean was implanted into four varieties of wheat of Zhougyu 5,Huaiyin 9628,Wenyou 1,Jimai 5 respectively via ion-beam mediation.There were 5 plants obtained whose protein content was higher than 18.5%,the highest one was 21.44%,There were 3 plants obtained whose protein content was lower than 11.5%,the lowest one was 10.96%.We can see that the whole DNA of soybean transformed into wheat via ion beam implantation can induce the increase in wheat protein content dramatically.The result also shows that the transformation efficiency of different gene types of wheat receptor varies greatly that the implanting time has a certain effect on the efficiency of transformation.
文摘Mutant strains of GOl12 and BM302 with a high 2-keto-L-gulonic acid (2KLG)transformation rate induced by ion beam implantation were separately and combinatorially com-pared with the original strains GO29 and BM80 to study the mutagenic effects of ion beam implan-tation.Both the sole GO112 and mixed BM302:GO112 demonstrated improved SNDH activityand 2KLG yield compared to the original strains.The mutant combinations of BM302:GO112showed a longer stationary phase and higher biomass than BM80:GO29.The mutant BM302exhibited a stronger capacity to maintain a stable pH environment at mixed fermentation withGluconobacter 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 dehy-drogenase (L-SNDH) from the supernate of BM302 was 1.6-fold higher than that of BM80.Genesencoded SNDH in GO29 and GOl12 were amplified and sequenced,and mutations including threetransitions (CG→TA,CG→TA,GC→AT) and one transversion (AT→TA) were confirmedfrom GO29 to GO112.The corresponding amino acid was changed as Leu→Phe,Arg→Glnand Asn→Lys.
基金supported by National Science Fund for Distinguished Young Scholars (No. 10225526)
文摘Vacuum treatment and ion-beam bombardment are two major processes in the low energy ion-beam implantation. To accurately study the contributions of these two major factors to the bioeffects separately, the M_1 generation variation of Arabidopsis thaliana with ion-beam implantation and vacuum treatment were compared through a series of key plant development parameters including morphological observation, biochemical assay and RAPD (random amplified polymorphic DNA) analysis. The results showed that ion-beam implantation had obvious effect on almost all of these parameters, and the vacuum treatment had some impacts on several morphological parameters such as the bolting time and the length of the primary stem. Taking the results together, the indication is that vacuum treatment has some slight contributions to the bioeffects of ion-beam implantation while ion-beam bombardment itself is the major creator of the bioeffects.
基金supported by the Chinese National "863" Project of "Sand Treating Technology for Plant Improvement by Ion Beam Combined with New Material" (No. 2002AA327070)
文摘We have developed a large number of exocrine glands on liquorice leaves and facilitated polysaccharide secretion. Liquorice polysaccharide possesses stronger bound water affinity to gaseous water compared with sucrose and glucose. Our results show that the bound water affinity of liquorice polysaccharide to gaseous water is 49.75% higher than glucose (p<0.01). With N^+ implantation (total dosage of 4.68×10^(16) ions/cm^2 and energy of 20 keV) into dry liquorice seeds, both the bound water affinity to gaseous water and the bound water content of dry liquorice leaf can be significantly increased 30.24% (p<0.01) and 36.51% (p<0.01) respectively compared with the sham-irradiated seeds. Meanwhile, with these parameters chosen for N^+ implantation into dry liquorice seeds, the leaf polysaccharide content under water stress (ψ_w=-1.5 MPa) can increase significantly (p<0.05) and the plant growth can also improve significantly (p<0.05).
文摘Single-particle microbeam as a powerful tool can open a research field to find answers to many enigmas in radiobiology. A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS), China. However there has been less research activities in this field concerning the original process of the interaction between low-energy ions and complicated, organisms. To address this challenge, an in situ multi-dimensional quantitative fluorescence microscopy system combined with the CAS-LIBB single-particle microbeam Ⅱ endstation is proposed. In this article, the rationale, logistics and development of many aspects of the proposed system are discussed.
基金the National Science Foundation for Distinguished Young Scholars of China(No.10225526)the Knowledge Innovation Program of the Chinese Academy Sciences(No.KSCX2-SW-324)the Foundation for University Key Teachers by the Ministry of Education of China(No.2005jq1135)
文摘Single particle microbeam(SPM)is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism.This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.
基金supported by the the National Major Technologies R&D Programme of China during the 10th Five-Year Plan Period(No.2001BA302B)the National Science Foundation for Distinguished Young Scholars(No.10225526)+1 种基金the Knowledge Innovation Programme of the Chinese Academy of Sciences(No.KSCX2-SW-324)the Foundation for University Key Teacher by the Ministry of Education(No.2005jq1135).
文摘The proposed multi-dimensional quantitative fluorescence microscopy for the CAS-LIBB single-particle microbeam Ⅱ endstation is a CCD-based imaging system. We systematicallyanalyse the theoretical and the practical considerations pertinent to choosing the right CCDcamera and unveiling the principles underlying multifarious parameters. Therefore, this analysiscan be a valuable tool in scrutinizing each parameter and clarifying proper usage of a scientificCCD camera.
