Although the complete nucleotide sequence of strawberry vein banding virus(SVBV) has been determined and bioinformatic analysis has revealed that the SVBV genome could encode seven proteins, the precise function of ea...Although the complete nucleotide sequence of strawberry vein banding virus(SVBV) has been determined and bioinformatic analysis has revealed that the SVBV genome could encode seven proteins, the precise function of each protein is unclear. This study provided evidence that the P1 protein of SVBV(SVBV-P1) possesses the following features. Bioinformatic and subcellular localization analyses showed that SVBV-P1 is localized in the cytoplasm and cell walls of epidermal cells in Nicotiana benthamiana, and it forms inclusion bodies associated with microtubules and the endoplasmic reticulum. Dilution experiments demonstrated that SVBV-P1 could move from the original agro-infiltrated cells to adjacent cells in N. benthamiana leaves. Further trans-complementation experiments demonstrated that SVBV-P1 could facilitate the intercellular movement of a movement-deficient potato virus X mutant in N. benthamiana leaves. Finally, yeast twohybrid and bimolecular fluorescence complementation assays revealed that SVBV-P1 could interact with the SVBV coat protein, which is a major component of Caulimovirus virions. Results of the electrophoretic mobility shift assay indicated that SVBV-P1 lacks DNA-binding capability. In summary, the results suggest that SVBV-P1 is probably a movement protein of SVBV, providing new insights into the function of movement proteins of the Caulimovirus genus.展开更多
CWMV-CP1 target gene and bar selection gene were co-transferred into commercial wheat variety of Yangmai158 by particle bombardment. In total, 145 resistant plants to 3 -5 mg L-1 Bialaphos were obtained, 21 plants wer...CWMV-CP1 target gene and bar selection gene were co-transferred into commercial wheat variety of Yangmai158 by particle bombardment. In total, 145 resistant plants to 3 -5 mg L-1 Bialaphos were obtained, 21 plants were identified to be positive in T0 generation by PCR-Southern test, and the transformation frequency had 0.99%. T1 plants were further tested by PCR and Southern hybridization. Results demonstrated that the alien resistance gene had been integrated into the wheat genome. The segregation ratio of CP1+ to CP1- in T1 generation was 1.0 to 1. 3, and didn't agree with Mendelian rule. RT-PCR result from T2 plants showed that the alien gene CWMV-CP1 had stable expression in wheat genetic background.展开更多
Many plant viruses utilize subgenomic RNA as gene expression strategy, therefore mapping subgenomic promoter(SGP) is extremely important for constructing viral vectors. Although Cucumber green mottle mosaic virus(CGMM...Many plant viruses utilize subgenomic RNA as gene expression strategy, therefore mapping subgenomic promoter(SGP) is extremely important for constructing viral vectors. Although Cucumber green mottle mosaic virus(CGMMV)-based virus vectors have been constructed, SGP of the coat protein(CP) has not yet mapped. To this end, we firstly presumed 13 nucleotides upstream of the start codon as the transcription starting site(TSS) as previous study identified by random amplification of c DNA ends(RACE). Secondly, the region from nucleotides –110 to +175 is the putative CP SGP, as predicted, a long stem loop structure by the secondary structure of RNA covering movement protein(MP) and CP. To map the CGMMV CP SGP, we further constructed a series of deletion mutants according to RNA secondary structure prediction. The deletion of TSS upstream significantly enhanced CP transcription when 105 nucleotides were retained before the CP TSS. For the downstream of CP TSS, we analyzed the expression of enhanced green fluorescent protein(EGFP) in a series of vectors with partial deletion of the CGMMV CP and found that the nucleotides from +71 to +91 played a key role in the EGFP expression at the transcription level, while EGFP showed the highest expression level when 160 nucleotides were retained downstream of the CP TSS. To confirm these results, we applied online software MEME to predict the motifs and cis-acting elements in the 466 nucleotides covering the sequences of deletion analysis. Conserved motifs and relative acting elements were in regions in which transcription levels were the highest or enhanced. To our best knowledge, this is the first mapping of CGMMV SGP.展开更多
Sweet potato is one of the first natural GMOs, genetically modified 8000 years ago by Agrobacterium rhizogenes as reported recently by Kyndt et al. A section of 10 kbp long DNA (Transferred- DNA or T-DNA) of the Ri (R...Sweet potato is one of the first natural GMOs, genetically modified 8000 years ago by Agrobacterium rhizogenes as reported recently by Kyndt et al. A section of 10 kbp long DNA (Transferred- DNA or T-DNA) of the Ri (Root-inducing) plasmid was transferred to the plant genome by A. rhizo-genes and has been maintained in all 291 hexaploid sweet potato cultivars of the world. The maintenance in the sweet potato genome and expression of two T-DNA genes for tryptophan-2-monooxygenease (iaaM) and for indole-3-acetamide hydrolase (iaaH) are likely to be physiologically significant since these enzymes convert tryptophan to indole-3-acetic acid, a major plant growth hormone auxin. Sweet potato (Ipomoea batatas (L.) Lam) is ranked the third most important root crop after potato and cassava, and the seventh in global food crop production with more than 126 million metric tons. Although sweet potato originated in Central or South America, China currently produces over 86% of world production with 109 million metric tons. In the United States, North Carolina is the leading producer with 38.5% of the 2007 sweet potato production, followed by California, Mississippi, and Louisiana with 23%, 19%, and 15.9%, respectively. Leaf curl virus diseases have been reported in sweet potato throughout the world. One of the causal agents is Sweet potato leaf curl virus (SPLCV) belonging to the genus Begomovirus (family Geminiviridae). Although SPLCV does not cause symptoms on Beauregard, one of the most predominant sweet potato cultivars in the US, it can reduce the yield up to 26%. Serological detection of SPLCV is not currently available due to the difficulties in obtaining purified virions that can be used as antigen for antiserum production. In attempts to obtain the coat protein (CP) of SPLCV for antibody production, primers were designed to amplify the CP gene. This gene was cloned into the expression vector pMAL-c2E as a fusion protein with maltose-binding protein, and transformed into Escherichia coli strain XL1-Blue. After gene induction, a fusion protein of 72 kDa was purified by amylose affinity chromatography. The yield of the purified fusion protein was approximately 200 μg/liter of bacterial culture. Digestion with enterokinase cleaved the fusion protein into a 42.5 kDa maltosebinding protein and a 29.4 kDa protein. The latter protein was identified by mass spectrometry analysis as the coat protein of SPLCV based on the fact that the mass spectrometry elucidated the sequences corresponding to 37% of amino acid positions of the SPLCV coat protein.展开更多
Yam mosaic virus (YMV), a Potyvirus, is a highly destructive pathogen of yam accounting for yield losses up to 40%. Apart from causing significant reduction in tuber size and quality, it restricts international exchan...Yam mosaic virus (YMV), a Potyvirus, is a highly destructive pathogen of yam accounting for yield losses up to 40%. Apart from causing significant reduction in tuber size and quality, it restricts international exchange of germplasms. It thus becomes crucial to get resistant or at least virus-free planting materials for farmers. This study was aimed at inducing resistance to YMV in tobacco by RNA silencing. An RNAi construct containing 161 bp fragment of <span style="font-family:Verdana;">YMV-coat protein (CP) </span><span style="font-family:Verdana;">gene was developed and used to produce transgenic tobacco lines expressing </span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;"> derived </span><span style="font-family:Verdana;">double stranded RNA (dsRNA)</span><span style="font-family:""><span style="font-family:Verdana;"> via </span><i><span style="font-family:Verdana;">Agrobacterium</span></i><span style="font-family:Verdana;">-mediated transformation. Of the eight T</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> transgenic lines inoculated with YMV, six (L1, L2, L3, L5, L7 and L8) showed immunity to YMV as no symptoms were detected, whereas two (L4 and L10) exhibited high resistance with mild symptoms limited to inoculation portions. No virus could be detected in uninoculated new leaves of the transgenic lines after RT-PCR and qPCR analyses of </span></span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">The presence of small interfering RNAs in transgenic</span><span style="font-family:MinionPro-Capt;"> </span><span style="font-family:Verdana;">lines after virus challenge indicates</span><span style="font-family:Verdana;"> that the resistance was acquired through RNA silencing.</span>展开更多
M13 phage＇is a filamentous bacteriophage containing a circular single-stranded DNA molecular, which is surrounded by approximately 2 800 copies of protein PVIII. In addition, there are five copies of each of proteins...M13 phage＇is a filamentous bacteriophage containing a circular single-stranded DNA molecular, which is surrounded by approximately 2 800 copies of protein PVIII. In addition, there are five copies of each of proteins PVII and PXI in one end, and five copies of each of proteins PVI and PUI on the other. These coat proteins have play an important role in the infection and assembly of M13 phage. With the development of phage display technology, these five coat proteins all can be used in phage display, which plays an increasingly important role in molecular detection and treatment.展开更多
<div style="text-align:justify;"> <em>Citrus tristeza virus</em> (CTV) is an important citrus pathogen causing considerable economic loss to citrus production. Knowledge on genetic evolutio...<div style="text-align:justify;"> <em>Citrus tristeza virus</em> (CTV) is an important citrus pathogen causing considerable economic loss to citrus production. Knowledge on genetic evolutionary of the CTV population in China remains limited. In this study, 1439 samples were collected from nine citrus-producing areas of China. The coat protein (CP) genes of CTV were amplified by RT-PCR, and sequenced to analyze the genetic evolution. Analysis of the base composition showed an AU preference pattern, with the GC content was lower than AU content. Nine CTV populations were clustered into one clade in neighbor-joining (NJ) tree, indicative of a close phylogenetic relationship among the populations in China. Analysis of molecular variation (AMOVA) revealed that 77.72% genetic variations of CTV populations were observed among populations, with an <em>F</em><sub>ST</sub> value of 0.223. The values of <em>d<sub>N</sub>/d<sub>S</sub></em> and neutrality test of <em>CP</em> gene were ranged from 0.016 to 0.082 and -1.377 to 1.456, respectively, the results suggesting that all of nine CTV populations were relatively constantly maintained under purifying selection. Our study demonstrated the genetic characteristics and molecular evolution relationship of CTV populations in China, and provided a theoretical basis for scientific control of CTV. </div>展开更多
Coated capillary columns were prepared by sol-gel technology and used in the separation of basic proteins with capillary zone electrophoresis. The results indicated that a significant decrease in protein adsorption wa...Coated capillary columns were prepared by sol-gel technology and used in the separation of basic proteins with capillary zone electrophoresis. The results indicated that a significant decrease in protein adsorption was obtained and EOF was also diminished to zero in the pH range of 3-10.展开更多
To obtain the P8 protein of Rice gall dwarf virus (RGDV) with biological activity,its outer coat protein gene S8 was expressed in Spodoptera frugiperda (Sf9) insect cells using the baculovirus expression system.The S8...To obtain the P8 protein of Rice gall dwarf virus (RGDV) with biological activity,its outer coat protein gene S8 was expressed in Spodoptera frugiperda (Sf9) insect cells using the baculovirus expression system.The S8 gene was subcloned into the pFastBacTM1 vector,to produce the recombinant baculovirus transfer vector pFB-S8.After transformation,pFB-S8 was introduced into the competent cells (E.coli DH10Bac) containing a shuttle vector,Bacmid,generating the recombinant bacmid rbpFB-S8.After being infected by recombinant baculovirus rvpFB-S8 at different multiplicities of infection,Sf9 cells were collected at different times and analyzed by SDS-PAGE,Western blotting and immunofluorescence microscopy.The expression level of the P8 protein was highest between 48-72 h after transfection of Sf9 cells.Immunofluorescence microscopy showed that P8 protein of RGDV formed punctate structures in the cytoplasm of Sf9 cells.展开更多
Hydrophilic silica/copolymer nanoparticles of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl e...Hydrophilic silica/copolymer nanoparticles of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl ether methacrylate (PEGMA) and poly(ethylene glycol) methacrylate (PEG), by using Three molar ratios of SiO<sub>2</sub>-Br/PEGMA/PEG as 1/42.46/19.44, 1/42.46/38.88 and 1/42.46/77.76. Their temperature sensitive behaviour, pH response and surface properties as protein-resistance coatings are characterized. 220 nm core-shell nanoparticles as P(PEGMA)-b-P(PEG) shell grafted on SiO2 core are formed in water solution, which gained LCST at 60<sup>。</sup>C - 77<sup>。</sup>C and good dispersion in water when pH > 5.0. The water-casted films by SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) obtain a little rough surface (Ra = 26.8 - 29.7 nm). While, the introduction of P(PEG) segments could slight increase the protein-repelling adsorption of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) films (△f = ?6.96 Hz ~ ?7.25 Hz) compared with SiO2-g-P(PEGMA) films (△f = ?9.5 Hz). Therefore, SiO2-g-P(PEGMA)-b-P(PEG) could be used as protein-resistance coatings.展开更多
基金supported by the grants from the National Natural Science Foundation of China(32072386 and 31801700)the Key Research and Development Project of Anhui Province,China(202004a06020013)the Postdoctoral Science Fund of Anhui Province,China(2019B360)。
文摘Although the complete nucleotide sequence of strawberry vein banding virus(SVBV) has been determined and bioinformatic analysis has revealed that the SVBV genome could encode seven proteins, the precise function of each protein is unclear. This study provided evidence that the P1 protein of SVBV(SVBV-P1) possesses the following features. Bioinformatic and subcellular localization analyses showed that SVBV-P1 is localized in the cytoplasm and cell walls of epidermal cells in Nicotiana benthamiana, and it forms inclusion bodies associated with microtubules and the endoplasmic reticulum. Dilution experiments demonstrated that SVBV-P1 could move from the original agro-infiltrated cells to adjacent cells in N. benthamiana leaves. Further trans-complementation experiments demonstrated that SVBV-P1 could facilitate the intercellular movement of a movement-deficient potato virus X mutant in N. benthamiana leaves. Finally, yeast twohybrid and bimolecular fluorescence complementation assays revealed that SVBV-P1 could interact with the SVBV coat protein, which is a major component of Caulimovirus virions. Results of the electrophoretic mobility shift assay indicated that SVBV-P1 lacks DNA-binding capability. In summary, the results suggest that SVBV-P1 is probably a movement protein of SVBV, providing new insights into the function of movement proteins of the Caulimovirus genus.
基金Thig study was supported by Europe Confederation International Cooperation with Developing Countries(ECINCO)Program(IC18-CT96-0049)Chinese“863”Program(2001-AA212111).
文摘CWMV-CP1 target gene and bar selection gene were co-transferred into commercial wheat variety of Yangmai158 by particle bombardment. In total, 145 resistant plants to 3 -5 mg L-1 Bialaphos were obtained, 21 plants were identified to be positive in T0 generation by PCR-Southern test, and the transformation frequency had 0.99%. T1 plants were further tested by PCR and Southern hybridization. Results demonstrated that the alien resistance gene had been integrated into the wheat genome. The segregation ratio of CP1+ to CP1- in T1 generation was 1.0 to 1. 3, and didn't agree with Mendelian rule. RT-PCR result from T2 plants showed that the alien gene CWMV-CP1 had stable expression in wheat genetic background.
基金supported by the National Natural Science Foundation of China (31571247)the grants from the earmarked fund for the China Agriculture Research System (CARS-26-13)the Agricultural Science and Technology Innovation Program (ASTIP), Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2018-ZFRI-08)
文摘Many plant viruses utilize subgenomic RNA as gene expression strategy, therefore mapping subgenomic promoter(SGP) is extremely important for constructing viral vectors. Although Cucumber green mottle mosaic virus(CGMMV)-based virus vectors have been constructed, SGP of the coat protein(CP) has not yet mapped. To this end, we firstly presumed 13 nucleotides upstream of the start codon as the transcription starting site(TSS) as previous study identified by random amplification of c DNA ends(RACE). Secondly, the region from nucleotides –110 to +175 is the putative CP SGP, as predicted, a long stem loop structure by the secondary structure of RNA covering movement protein(MP) and CP. To map the CGMMV CP SGP, we further constructed a series of deletion mutants according to RNA secondary structure prediction. The deletion of TSS upstream significantly enhanced CP transcription when 105 nucleotides were retained before the CP TSS. For the downstream of CP TSS, we analyzed the expression of enhanced green fluorescent protein(EGFP) in a series of vectors with partial deletion of the CGMMV CP and found that the nucleotides from +71 to +91 played a key role in the EGFP expression at the transcription level, while EGFP showed the highest expression level when 160 nucleotides were retained downstream of the CP TSS. To confirm these results, we applied online software MEME to predict the motifs and cis-acting elements in the 466 nucleotides covering the sequences of deletion analysis. Conserved motifs and relative acting elements were in regions in which transcription levels were the highest or enhanced. To our best knowledge, this is the first mapping of CGMMV SGP.
文摘Sweet potato is one of the first natural GMOs, genetically modified 8000 years ago by Agrobacterium rhizogenes as reported recently by Kyndt et al. A section of 10 kbp long DNA (Transferred- DNA or T-DNA) of the Ri (Root-inducing) plasmid was transferred to the plant genome by A. rhizo-genes and has been maintained in all 291 hexaploid sweet potato cultivars of the world. The maintenance in the sweet potato genome and expression of two T-DNA genes for tryptophan-2-monooxygenease (iaaM) and for indole-3-acetamide hydrolase (iaaH) are likely to be physiologically significant since these enzymes convert tryptophan to indole-3-acetic acid, a major plant growth hormone auxin. Sweet potato (Ipomoea batatas (L.) Lam) is ranked the third most important root crop after potato and cassava, and the seventh in global food crop production with more than 126 million metric tons. Although sweet potato originated in Central or South America, China currently produces over 86% of world production with 109 million metric tons. In the United States, North Carolina is the leading producer with 38.5% of the 2007 sweet potato production, followed by California, Mississippi, and Louisiana with 23%, 19%, and 15.9%, respectively. Leaf curl virus diseases have been reported in sweet potato throughout the world. One of the causal agents is Sweet potato leaf curl virus (SPLCV) belonging to the genus Begomovirus (family Geminiviridae). Although SPLCV does not cause symptoms on Beauregard, one of the most predominant sweet potato cultivars in the US, it can reduce the yield up to 26%. Serological detection of SPLCV is not currently available due to the difficulties in obtaining purified virions that can be used as antigen for antiserum production. In attempts to obtain the coat protein (CP) of SPLCV for antibody production, primers were designed to amplify the CP gene. This gene was cloned into the expression vector pMAL-c2E as a fusion protein with maltose-binding protein, and transformed into Escherichia coli strain XL1-Blue. After gene induction, a fusion protein of 72 kDa was purified by amylose affinity chromatography. The yield of the purified fusion protein was approximately 200 μg/liter of bacterial culture. Digestion with enterokinase cleaved the fusion protein into a 42.5 kDa maltosebinding protein and a 29.4 kDa protein. The latter protein was identified by mass spectrometry analysis as the coat protein of SPLCV based on the fact that the mass spectrometry elucidated the sequences corresponding to 37% of amino acid positions of the SPLCV coat protein.
文摘Yam mosaic virus (YMV), a Potyvirus, is a highly destructive pathogen of yam accounting for yield losses up to 40%. Apart from causing significant reduction in tuber size and quality, it restricts international exchange of germplasms. It thus becomes crucial to get resistant or at least virus-free planting materials for farmers. This study was aimed at inducing resistance to YMV in tobacco by RNA silencing. An RNAi construct containing 161 bp fragment of <span style="font-family:Verdana;">YMV-coat protein (CP) </span><span style="font-family:Verdana;">gene was developed and used to produce transgenic tobacco lines expressing </span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;"> derived </span><span style="font-family:Verdana;">double stranded RNA (dsRNA)</span><span style="font-family:""><span style="font-family:Verdana;"> via </span><i><span style="font-family:Verdana;">Agrobacterium</span></i><span style="font-family:Verdana;">-mediated transformation. Of the eight T</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> transgenic lines inoculated with YMV, six (L1, L2, L3, L5, L7 and L8) showed immunity to YMV as no symptoms were detected, whereas two (L4 and L10) exhibited high resistance with mild symptoms limited to inoculation portions. No virus could be detected in uninoculated new leaves of the transgenic lines after RT-PCR and qPCR analyses of </span></span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">The presence of small interfering RNAs in transgenic</span><span style="font-family:MinionPro-Capt;"> </span><span style="font-family:Verdana;">lines after virus challenge indicates</span><span style="font-family:Verdana;"> that the resistance was acquired through RNA silencing.</span>
文摘M13 phage＇is a filamentous bacteriophage containing a circular single-stranded DNA molecular, which is surrounded by approximately 2 800 copies of protein PVIII. In addition, there are five copies of each of proteins PVII and PXI in one end, and five copies of each of proteins PVI and PUI on the other. These coat proteins have play an important role in the infection and assembly of M13 phage. With the development of phage display technology, these five coat proteins all can be used in phage display, which plays an increasingly important role in molecular detection and treatment.
文摘<div style="text-align:justify;"> <em>Citrus tristeza virus</em> (CTV) is an important citrus pathogen causing considerable economic loss to citrus production. Knowledge on genetic evolutionary of the CTV population in China remains limited. In this study, 1439 samples were collected from nine citrus-producing areas of China. The coat protein (CP) genes of CTV were amplified by RT-PCR, and sequenced to analyze the genetic evolution. Analysis of the base composition showed an AU preference pattern, with the GC content was lower than AU content. Nine CTV populations were clustered into one clade in neighbor-joining (NJ) tree, indicative of a close phylogenetic relationship among the populations in China. Analysis of molecular variation (AMOVA) revealed that 77.72% genetic variations of CTV populations were observed among populations, with an <em>F</em><sub>ST</sub> value of 0.223. The values of <em>d<sub>N</sub>/d<sub>S</sub></em> and neutrality test of <em>CP</em> gene were ranged from 0.016 to 0.082 and -1.377 to 1.456, respectively, the results suggesting that all of nine CTV populations were relatively constantly maintained under purifying selection. Our study demonstrated the genetic characteristics and molecular evolution relationship of CTV populations in China, and provided a theoretical basis for scientific control of CTV. </div>
文摘Coated capillary columns were prepared by sol-gel technology and used in the separation of basic proteins with capillary zone electrophoresis. The results indicated that a significant decrease in protein adsorption was obtained and EOF was also diminished to zero in the pH range of 3-10.
基金supported by the National Science Foundation of China (30970135)The Key Project of Genetically Modified Organisms Breeding(2009ZX08009-044B)+1 种基金the Natural Science Foundation of Fujian Province of China (No.2006J0065)the Public-interest Scientific Institution Basal Research Fund of Fujian Province (2009R10029-3)
文摘To obtain the P8 protein of Rice gall dwarf virus (RGDV) with biological activity,its outer coat protein gene S8 was expressed in Spodoptera frugiperda (Sf9) insect cells using the baculovirus expression system.The S8 gene was subcloned into the pFastBacTM1 vector,to produce the recombinant baculovirus transfer vector pFB-S8.After transformation,pFB-S8 was introduced into the competent cells (E.coli DH10Bac) containing a shuttle vector,Bacmid,generating the recombinant bacmid rbpFB-S8.After being infected by recombinant baculovirus rvpFB-S8 at different multiplicities of infection,Sf9 cells were collected at different times and analyzed by SDS-PAGE,Western blotting and immunofluorescence microscopy.The expression level of the P8 protein was highest between 48-72 h after transfection of Sf9 cells.Immunofluorescence microscopy showed that P8 protein of RGDV formed punctate structures in the cytoplasm of Sf9 cells.
文摘Hydrophilic silica/copolymer nanoparticles of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl ether methacrylate (PEGMA) and poly(ethylene glycol) methacrylate (PEG), by using Three molar ratios of SiO<sub>2</sub>-Br/PEGMA/PEG as 1/42.46/19.44, 1/42.46/38.88 and 1/42.46/77.76. Their temperature sensitive behaviour, pH response and surface properties as protein-resistance coatings are characterized. 220 nm core-shell nanoparticles as P(PEGMA)-b-P(PEG) shell grafted on SiO2 core are formed in water solution, which gained LCST at 60<sup>。</sup>C - 77<sup>。</sup>C and good dispersion in water when pH > 5.0. The water-casted films by SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) obtain a little rough surface (Ra = 26.8 - 29.7 nm). While, the introduction of P(PEG) segments could slight increase the protein-repelling adsorption of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) films (△f = ?6.96 Hz ~ ?7.25 Hz) compared with SiO2-g-P(PEGMA) films (△f = ?9.5 Hz). Therefore, SiO2-g-P(PEGMA)-b-P(PEG) could be used as protein-resistance coatings.
