【目的】通过探究花叶矢竹体细胞无性系变异株系茎秆形态、解剖结构及细胞壁组分等特征的动态变化,揭示花叶矢竹茎秆倒伏的生理机制。【方法】以发生体细胞无性系变异的花叶矢竹矮化倒伏突变体(dwarf and lodging mutant,DWF)为研究对象...【目的】通过探究花叶矢竹体细胞无性系变异株系茎秆形态、解剖结构及细胞壁组分等特征的动态变化,揭示花叶矢竹茎秆倒伏的生理机制。【方法】以发生体细胞无性系变异的花叶矢竹矮化倒伏突变体(dwarf and lodging mutant,DWF)为研究对象,以正常组织培养的花叶矢竹(WT)为对照,同时移栽90、180、270、和360天后,分别调查其新生竹秆的表型、横切面解剖结构、细胞壁组分含量的变化。【结果】DWF在不同移栽时期中茎秆形态、解剖结构、细胞壁组分含量与WT差异显著。1)相较于WT,DWF茎秆在4个移栽时期中均发生不同程度的倒伏,移栽90天时茎秆与地面夹角为35.27°,茎秆倒伏程度最大,移栽360天时茎秆与地面夹角为73.13°,茎秆倒伏程度最小。2)DWF茎秆直径、茎秆高度、基部节间长度极显著低于WT,移栽360天时差异最大;DWF生长缓慢,移栽270~360天时,DWF新生茎秆高度增幅仅为WT的21.41%,新生茎秆直径增幅只有WT的17.49%。3)DWF大小维管束数量及面积均极显著低于WT,移栽360天时DWF大维管束数量及面积分别比WT低65.71%及55.35%,小维管束数量及面积分别比WT低75.44%及55.51%,WT新生茎秆大小维管束数量及面积快速增长时,DWF增幅缓慢;DWF厚壁组织厚度变薄,在4个时期中与WT均存在极显著差异,分别比WT低50.21%、55.77%、54.59%、45.41%;DWF髓腔发育缓慢,移栽270天与360天时出现髓腔,髓腔直径极显著低于WT。4)随着移栽时间的延长,DWF新生茎秆的木质素、纤维素含量增加,但极显著低于WT,且半纤维素含量无显著差异,节间木质素及纤维素沉积程度也低于WT。5)DWF茎秆倒伏程度与其茎秆直径存在显著负相关关系,与大小维管束数量及面积、厚壁组织厚度、木质素及纤维素含量存在极显著负相关关系。【结论】相较于花叶矢竹WT,DWF在发育过程中,茎秆高度增长滞缓和呈现矮化,茎秆强度弱和发生倒伏。DWF茎秆直径小、大小维管束的数量少和面积小、厚壁组织厚度低,是其发生倒伏的一个重要原因;DWF细胞壁的木质素及纤维素含量低,造成其茎秆强度弱,是其发生倒伏的另一原因。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 muta...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 GO 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 GO and GI13 were estimated.展开更多
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 ...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.展开更多
This study investigates the biocontrol potential of Trichoderma asperellum mutants against Rhizoctonia solani, Alternaria alternata, and Fusarium oxysporum and growth promotion of Populus davidiana 9 P. alba var.pyram...This study investigates the biocontrol potential of Trichoderma asperellum mutants against Rhizoctonia solani, Alternaria alternata, and Fusarium oxysporum and growth promotion of Populus davidiana 9 P. alba var.pyramidalis(Pd Pap poplar) seedlings. A T-DNA insertion mutant library of T. asperellum was constructed using Agrobacterium tumefaciens-mediated transformation.Sixty-five positive transformants(T1–T65) were obtained.Growth rates of the mutants T39 and T45 were the same,39.68% faster than the WT. In toxin tolerance tests, only T39 had greater tolerance to A. alternata fermentation broth than the WT, but mutant T45 had the same tolerance as the WT to all fermentation broths. Furthermore, T39 and T45 had a greater antagonistic ability than the WT strain against R. solani and A. alternata. The inhibition rate of the mutants T39 and T45 against A. alternata are 73.92% and80.76%, respectively, and 63.51% and 63.74%, respectively. Furthermore, the three strains increased the activities of superoxide dismutases, peroxidase, catalase(CAT)and phenylalanine ammonia lyase(PAL) in Pd Pap seedling leaves. CAT and PAL activity in the Pd Pap seedling leaveswas 11.25 and 5.50 times higher, respectively, in the presence of T39 than in the control group and 12 and 6.35 times higher, respectively, in the presence of T45 than in the control group. All three strains promoted seedling growth and the root and stem development, especially mutant T45. Mutants T39 and T45 reduced the incidence of pathogenic fungi in poplar and stimulated poplar seedling growth.展开更多
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...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.展开更多
A screen for Arabidopsis fertility mutants, mutagenized by low-energy argon ion beam, yielded two partial male-sterile mutants tc243-1 and tc243-2 which have similar phenotypes. tc243-2 was investigated in detail. The...A screen for Arabidopsis fertility mutants, mutagenized by low-energy argon ion beam, yielded two partial male-sterile mutants tc243-1 and tc243-2 which have similar phenotypes. tc243-2 was investigated in detail. The segregation ratio of the mutant phenotypes in the M2 pools suggested that mutation behaved as single Mendelian recessive mutations, tc243 showed a series of mutant phenotypes, among which partial male-sterile was its striking mutant characteristic. Phenotype analysis indicates that there are four factors leading to male sterility, a. Floral organs normally develop inside the closed bud, but the anther filaments do not elongate sufficiently to position the locules above the stigma at anthesis, b. The anther locules do not dehisce at the time of flower opening （although limited dehiscence occurs later）, c. Pollens of mutant plants develop into several types of pollens at the trinucleated stage. as determined by staining with DAPI （4＇,6-diamidino-2-phenylindole）. which shows a variable size. shape and number of nucleus. d. The viability of pollens is lower than that of the wild type on the germination test in vivo and vitro.展开更多
In the present study autotetraploid rice IR36-4X was treated by an ion implantation technique with nitrogen ion beams. A polyembryonic mutant （named IR36-Shuang） was identified in the M2 generation. The mutant line ...In the present study autotetraploid rice IR36-4X was treated by an ion implantation technique with nitrogen ion beams. A polyembryonic mutant （named IR36-Shuang） was identified in the M2 generation. The mutant line and its offspring were systematically investigated in regard to their major agronomic properties and the rate of polyembryonic seedling in the M3-M6 generation. The abnormal phenomena in the embryo sac development and the cytological mechanism of the initiation of additional embryo in IR36-Shuang were observed by Laser Scanning Confocal Microscopy. The results were as follows. 1） The plant height, the panicle length and 1000 grain weight of IRB6-Shuang were lower than that of its control by 35.41%, 5.08% and 15.72% respectively, Moreover, the setting percentage decreased 12.39% compared with that in normal IRB6-4X plants. 2） The polyembryonic trait of IRB6-Shuang was genetically stable and the frequency of the polyembryonic seedlings in the IR36-Shuang line was also relatively stable. 3） The rate of abnormal embryo sacs in IR36-Shuang was significantly higher than that in the control IR36-4X. 4） The additional embryo in IR36-Shuang might arise from the double Jet of embryo sacs in a single owry, antipodal cells or endosperm cells. These results suggest that IRB6-Shuang is a polyembryonic mutant and a new apomixis rice line induced by low energy ion implantation. The prospects for the application in production of the IR36-Shuang line are also discussed. The present study may provide a basis for future investigations of apomixis rice breeding via the ion implantation biotechnology.展开更多
Mucosal vaccination has been getting more and more recognition because of its compliance and low risk of spreading infectious disease by contaminated syringes used in subcutaneous immunization. However, most vaccines ...Mucosal vaccination has been getting more and more recognition because of its compliance and low risk of spreading infectious disease by contaminated syringes used in subcutaneous immunization. However, most vaccines are unable to induce immune responses when given mucosally, and require the use of strong adjuvant for effective delivery systems. Heat-labile enterotoxin (LT) and Cholera toxin(CT) are powerful mucosal adjuvants when co-administered with soluble antigens. But high toxicity hampers their use in humans. Thanks to the fine knowledge of the structure-function relationship of LT and CT, many nontoxic or low toxic mutants have been generated, part of them retain high adjuvanticity of mucosal immunization. Among these mutants, LTS63K, LTA72R, LTR192G and CTE29H, CTE112K have been widely investigated. LTS63K and CTE112K are fully non toxic, whereas LTA72R and CTE29H are low toxic, and LTR192G is nontoxic in vitro(it remains the same toxicity as wild type LT in vivo). These mutants are extremely active as mucosal adjuvants when co-administrated with a variety of antigens in different animal models. They will be investigated more widely and deeply in the future. Some of them will be tested soon in human bodies.展开更多
Objective: To study the effects of the fixed-point mutant on growth cycle and ultrastructure of the Calmodulin fixed-point mutant yeast. Methods: Growth cycle and ultrastructure of the Calmodulin fixed-point mutant ye...Objective: To study the effects of the fixed-point mutant on growth cycle and ultrastructure of the Calmodulin fixed-point mutant yeast. Methods: Growth cycle and ultrastructure of the Calmodulin fixed-point mutant yeast were studied by using cytometry and scan electron microscope. Results: After culture at 30'C for 36 h, the content of aneuploidy of the temperature-sensitive recombinant yeast monoploid B(F92+) and E(F89+FH1 + ) strains were 63. 87% and 63. 55%, respectively. These were significantly different from control OP<0. 01) ; The content of the non-temperature-sensitive recombinant yeast monoploid A(F89+) and C(F141+) strains were 100. 00% and 99. 97% , respectively, which were not significantly different from control value (P>0. 05). Observed by scan electron microscope, the control group, A and C strain's buds were spherical or oval and those bud-necks were fairly shorter; the B and E strain's buds were slender, some cell were abnormal and some buds might show spherical or oval. Conclusion: DNA division and growth velocity of the temperature-sensitive recombinant B and E strains are slower than those of control group and the non-temperature-sensitive recombinant A and C strains.展开更多
Tryptophan （Trp） is an intrinsic fluorescent probe for detecting the site-specified dynamics inside/outside protein. It is found that the Trp can easily be inserted in desired sites of protein, which affects the int...Tryptophan （Trp） is an intrinsic fluorescent probe for detecting the site-specified dynamics inside/outside protein. It is found that the Trp can easily be inserted in desired sites of protein, which affects the integrity of the overall structure. To evaluate this effect, we design thirteen double point mutants of staphylococcal nuclease, each of which has a single Trp residue planted at an internal site. The studies on Trp fluorescence, ANS-binding fluorescence, far- and near-UV CD spectra, and enzymatic activity are carried out. It is found that the mutation at the hydrophobic core of protein generates molten globular state conformation, which is a loose structure compared to their original compactness in wild type （WT）. Its enzyme activity and surface hydrophobicity are also affected. The studies show that by proper site designing and external binding, Trp mutagenesis is a suitable method for carrying out the study on site specified dynamics of proteins.展开更多
Trichoderma aureoviride mutant T1010 was cultured in media containing different nutrients. Statistics showed significant differences and the results described below: The C/N tested were 3∶1, 6∶1, 12∶1, 24∶1,48∶1....Trichoderma aureoviride mutant T1010 was cultured in media containing different nutrients. Statistics showed significant differences and the results described below: The C/N tested were 3∶1, 6∶1, 12∶1, 24∶1,48∶1. The best C/N was 24∶1. The amount of spores was 4.0×109 cfu/plate. The best carbon source among glucose, sucrose, maltose, lactose, cellulose and starch was the last one. With a starch-containing medium, T1010 produced 5.3×109 cfu/plate. The asparagine was the best nitrogen source. T1010 absorbed it easily and produced 9.6×109 cfu/plate. K, Mg, P, S, Fe were important to support T1010 growth and sporulation. In the absence of K, P, and Fe, Trichoderma grew poorly, while Mg didn’t seem to help Trichoderma colony development. A little amount of vitamins allwed T1010 to grow better. This data allowed us to improve the cultivation of Trichoderma at industrial level.展开更多
文摘【目的】通过探究花叶矢竹体细胞无性系变异株系茎秆形态、解剖结构及细胞壁组分等特征的动态变化,揭示花叶矢竹茎秆倒伏的生理机制。【方法】以发生体细胞无性系变异的花叶矢竹矮化倒伏突变体(dwarf and lodging mutant,DWF)为研究对象,以正常组织培养的花叶矢竹(WT)为对照,同时移栽90、180、270、和360天后,分别调查其新生竹秆的表型、横切面解剖结构、细胞壁组分含量的变化。【结果】DWF在不同移栽时期中茎秆形态、解剖结构、细胞壁组分含量与WT差异显著。1)相较于WT,DWF茎秆在4个移栽时期中均发生不同程度的倒伏,移栽90天时茎秆与地面夹角为35.27°,茎秆倒伏程度最大,移栽360天时茎秆与地面夹角为73.13°,茎秆倒伏程度最小。2)DWF茎秆直径、茎秆高度、基部节间长度极显著低于WT,移栽360天时差异最大;DWF生长缓慢,移栽270~360天时,DWF新生茎秆高度增幅仅为WT的21.41%,新生茎秆直径增幅只有WT的17.49%。3)DWF大小维管束数量及面积均极显著低于WT,移栽360天时DWF大维管束数量及面积分别比WT低65.71%及55.35%,小维管束数量及面积分别比WT低75.44%及55.51%,WT新生茎秆大小维管束数量及面积快速增长时,DWF增幅缓慢;DWF厚壁组织厚度变薄,在4个时期中与WT均存在极显著差异,分别比WT低50.21%、55.77%、54.59%、45.41%;DWF髓腔发育缓慢,移栽270天与360天时出现髓腔,髓腔直径极显著低于WT。4)随着移栽时间的延长,DWF新生茎秆的木质素、纤维素含量增加,但极显著低于WT,且半纤维素含量无显著差异,节间木质素及纤维素沉积程度也低于WT。5)DWF茎秆倒伏程度与其茎秆直径存在显著负相关关系,与大小维管束数量及面积、厚壁组织厚度、木质素及纤维素含量存在极显著负相关关系。【结论】相较于花叶矢竹WT,DWF在发育过程中,茎秆高度增长滞缓和呈现矮化,茎秆强度弱和发生倒伏。DWF茎秆直径小、大小维管束的数量少和面积小、厚壁组织厚度低,是其发生倒伏的一个重要原因;DWF细胞壁的木质素及纤维素含量低,造成其茎秆强度弱,是其发生倒伏的另一原因。
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 GO 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 GO and GI13 were estimated.
基金supported by National Natural Science Foundation of China (No.30800204)Chinese Ministry of Agriculture supported by the Open Project of the Chinese Academy of Sciences
文摘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.
基金supported by the National High Technology Research and Development Program(13th Five-Year Plan Program,Grant Number 2016YFC0501505)the Fundamental Research Funds of the Central University,China(Grant Number 2572017CA06)。
文摘This study investigates the biocontrol potential of Trichoderma asperellum mutants against Rhizoctonia solani, Alternaria alternata, and Fusarium oxysporum and growth promotion of Populus davidiana 9 P. alba var.pyramidalis(Pd Pap poplar) seedlings. A T-DNA insertion mutant library of T. asperellum was constructed using Agrobacterium tumefaciens-mediated transformation.Sixty-five positive transformants(T1–T65) were obtained.Growth rates of the mutants T39 and T45 were the same,39.68% faster than the WT. In toxin tolerance tests, only T39 had greater tolerance to A. alternata fermentation broth than the WT, but mutant T45 had the same tolerance as the WT to all fermentation broths. Furthermore, T39 and T45 had a greater antagonistic ability than the WT strain against R. solani and A. alternata. The inhibition rate of the mutants T39 and T45 against A. alternata are 73.92% and80.76%, respectively, and 63.51% and 63.74%, respectively. Furthermore, the three strains increased the activities of superoxide dismutases, peroxidase, catalase(CAT)and phenylalanine ammonia lyase(PAL) in Pd Pap seedling leaves. CAT and PAL activity in the Pd Pap seedling leaveswas 11.25 and 5.50 times higher, respectively, in the presence of T39 than in the control group and 12 and 6.35 times higher, respectively, in the presence of T45 than in the control group. All three strains promoted seedling growth and the root and stem development, especially mutant T45. Mutants T39 and T45 reduced the incidence of pathogenic fungi in poplar and stimulated poplar seedling growth.
基金supported by the National Natural Science Foundation of China(Grant Nos.11205218,11275171,and 11405234)the Knowledge Innovation Project of the Chinese Academy of Sciences(CAS)(No.KJCX2-EW-N05)+1 种基金CAS‘‘Light of West China’’Program(No.29Y506020)the Youth Innovation Promotion Association of CAS(No.29Y506030)supported this study
文摘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.
基金Key Innovative Project of Chinese Academy of Sciences(No.KSCX2-SW-324)Director's Foundation of the Institute of Plasma Physics(No.152900500301)
文摘A screen for Arabidopsis fertility mutants, mutagenized by low-energy argon ion beam, yielded two partial male-sterile mutants tc243-1 and tc243-2 which have similar phenotypes. tc243-2 was investigated in detail. The segregation ratio of the mutant phenotypes in the M2 pools suggested that mutation behaved as single Mendelian recessive mutations, tc243 showed a series of mutant phenotypes, among which partial male-sterile was its striking mutant characteristic. Phenotype analysis indicates that there are four factors leading to male sterility, a. Floral organs normally develop inside the closed bud, but the anther filaments do not elongate sufficiently to position the locules above the stigma at anthesis, b. The anther locules do not dehisce at the time of flower opening （although limited dehiscence occurs later）, c. Pollens of mutant plants develop into several types of pollens at the trinucleated stage. as determined by staining with DAPI （4＇,6-diamidino-2-phenylindole）. which shows a variable size. shape and number of nucleus. d. The viability of pollens is lower than that of the wild type on the germination test in vivo and vitro.
基金supported by National Key Projects of China(No.2001BA302B)
文摘In the present study autotetraploid rice IR36-4X was treated by an ion implantation technique with nitrogen ion beams. A polyembryonic mutant （named IR36-Shuang） was identified in the M2 generation. The mutant line and its offspring were systematically investigated in regard to their major agronomic properties and the rate of polyembryonic seedling in the M3-M6 generation. The abnormal phenomena in the embryo sac development and the cytological mechanism of the initiation of additional embryo in IR36-Shuang were observed by Laser Scanning Confocal Microscopy. The results were as follows. 1） The plant height, the panicle length and 1000 grain weight of IRB6-Shuang were lower than that of its control by 35.41%, 5.08% and 15.72% respectively, Moreover, the setting percentage decreased 12.39% compared with that in normal IRB6-4X plants. 2） The polyembryonic trait of IRB6-Shuang was genetically stable and the frequency of the polyembryonic seedlings in the IR36-Shuang line was also relatively stable. 3） The rate of abnormal embryo sacs in IR36-Shuang was significantly higher than that in the control IR36-4X. 4） The additional embryo in IR36-Shuang might arise from the double Jet of embryo sacs in a single owry, antipodal cells or endosperm cells. These results suggest that IRB6-Shuang is a polyembryonic mutant and a new apomixis rice line induced by low energy ion implantation. The prospects for the application in production of the IR36-Shuang line are also discussed. The present study may provide a basis for future investigations of apomixis rice breeding via the ion implantation biotechnology.
文摘Mucosal vaccination has been getting more and more recognition because of its compliance and low risk of spreading infectious disease by contaminated syringes used in subcutaneous immunization. However, most vaccines are unable to induce immune responses when given mucosally, and require the use of strong adjuvant for effective delivery systems. Heat-labile enterotoxin (LT) and Cholera toxin(CT) are powerful mucosal adjuvants when co-administered with soluble antigens. But high toxicity hampers their use in humans. Thanks to the fine knowledge of the structure-function relationship of LT and CT, many nontoxic or low toxic mutants have been generated, part of them retain high adjuvanticity of mucosal immunization. Among these mutants, LTS63K, LTA72R, LTR192G and CTE29H, CTE112K have been widely investigated. LTS63K and CTE112K are fully non toxic, whereas LTA72R and CTE29H are low toxic, and LTR192G is nontoxic in vitro(it remains the same toxicity as wild type LT in vivo). These mutants are extremely active as mucosal adjuvants when co-administrated with a variety of antigens in different animal models. They will be investigated more widely and deeply in the future. Some of them will be tested soon in human bodies.
基金Supported by the National Natural Science Foundation of China (No. 39870012)
文摘Objective: To study the effects of the fixed-point mutant on growth cycle and ultrastructure of the Calmodulin fixed-point mutant yeast. Methods: Growth cycle and ultrastructure of the Calmodulin fixed-point mutant yeast were studied by using cytometry and scan electron microscope. Results: After culture at 30'C for 36 h, the content of aneuploidy of the temperature-sensitive recombinant yeast monoploid B(F92+) and E(F89+FH1 + ) strains were 63. 87% and 63. 55%, respectively. These were significantly different from control OP<0. 01) ; The content of the non-temperature-sensitive recombinant yeast monoploid A(F89+) and C(F141+) strains were 100. 00% and 99. 97% , respectively, which were not significantly different from control value (P>0. 05). Observed by scan electron microscope, the control group, A and C strain's buds were spherical or oval and those bud-necks were fairly shorter; the B and E strain's buds were slender, some cell were abnormal and some buds might show spherical or oval. Conclusion: DNA division and growth velocity of the temperature-sensitive recombinant B and E strains are slower than those of control group and the non-temperature-sensitive recombinant A and C strains.
基金Supported by the National Key Basic Research Program of China under Grant Nos 2013CB921904,2013CB328701-2013CB328706the National Natural Science Foundation of China under Grant Nos 11074016,11121091,61177020,11134001and 10828407
文摘Tryptophan （Trp） is an intrinsic fluorescent probe for detecting the site-specified dynamics inside/outside protein. It is found that the Trp can easily be inserted in desired sites of protein, which affects the integrity of the overall structure. To evaluate this effect, we design thirteen double point mutants of staphylococcal nuclease, each of which has a single Trp residue planted at an internal site. The studies on Trp fluorescence, ANS-binding fluorescence, far- and near-UV CD spectra, and enzymatic activity are carried out. It is found that the mutation at the hydrophobic core of protein generates molten globular state conformation, which is a loose structure compared to their original compactness in wild type （WT）. Its enzyme activity and surface hydrophobicity are also affected. The studies show that by proper site designing and external binding, Trp mutagenesis is a suitable method for carrying out the study on site specified dynamics of proteins.
文摘Trichoderma aureoviride mutant T1010 was cultured in media containing different nutrients. Statistics showed significant differences and the results described below: The C/N tested were 3∶1, 6∶1, 12∶1, 24∶1,48∶1. The best C/N was 24∶1. The amount of spores was 4.0×109 cfu/plate. The best carbon source among glucose, sucrose, maltose, lactose, cellulose and starch was the last one. With a starch-containing medium, T1010 produced 5.3×109 cfu/plate. The asparagine was the best nitrogen source. T1010 absorbed it easily and produced 9.6×109 cfu/plate. K, Mg, P, S, Fe were important to support T1010 growth and sporulation. In the absence of K, P, and Fe, Trichoderma grew poorly, while Mg didn’t seem to help Trichoderma colony development. A little amount of vitamins allwed T1010 to grow better. This data allowed us to improve the cultivation of Trichoderma at industrial level.
