Banana bunchy top virus Chinese Zhangzhou isolate (BBTV-ZZ) DNA 4 was amplified by PCR and cloned. Sequence analysis showed that BBTV-ZZ DNA 4 is 1 039 nucleotides (nts) in length and this virus could be one member of...Banana bunchy top virus Chinese Zhangzhou isolate (BBTV-ZZ) DNA 4 was amplified by PCR and cloned. Sequence analysis showed that BBTV-ZZ DNA 4 is 1 039 nucleotides (nts) in length and this virus could be one member of BBTV Asian group. Transcriptional initiation site A, which is at the 269 nucleotide, was preliminarily determined by using 5' RACE method. BBTV-ZZ DNA 4 non-coding region was sub-cloned by PCR and inserted into upstream of gfp : : gus plant expression vector pCAMBIA 1304 to construct recombinant plasmid pTA2. Agrobacterium tumefaciens harboring pTA2 was injected into leaves of the tobacco (Nicotiana tabacum L. cv. Xanthi NC) via Agrobacterium-infiltration procedure. Transient expressions of GUS and GFP were determined in injected leaves 3 - 5 d later. GUS activities of pTA2, pCAMBIA 1304 injected and non-injected tobacco leaves respectively were 1.007 0 pmol MU(.)mug(-1.)min(-1), 2.069 0 pmol MU(.)mug(-1.)min(-1) and 0.021 4 pmol MU(.)mug(-1.)min(-1). Indirect ELISA for GFP in 1 mg total protein from pTA2, pCAMBIA 1304 injected and non-injected leaves showed an A(490 nm) value of 89.577, 100.440 and 3.287, respectively. These results showed that the non-coding region of BBTV-ZZ DNA 4 has a promoter activity not only in the virus replication in monocot, but also in driving the expression of a foreign gene in dicot plants.展开更多
This paper reports that bunchy flake-like nano-graphite crystallite films （BNGCFs） were deposited on Si substrates by using the microwave chemical vapour deposition technique. Furthermore the BNGCFs were characteriz...This paper reports that bunchy flake-like nano-graphite crystallite films （BNGCFs） were deposited on Si substrates by using the microwave chemical vapour deposition technique. Furthermore the BNGCFs were characterized by x-ray diffraction spectra, scanning electron microscopy, Raman spectra and field emission （FE） I-V measurements, and a lowest turn-on field of 1.5 V/μm, and a high average emission current density of 30 mA/cm2 at a macroscopic electric field of 8.0V/μm were obtained. The J-E data did not follow the original Fowler-Nordheim （F-N） relation since they were not well represented in the F-N plot by a straight line. A model considering the F-N mechanism, and the statistic effects of FE tip structures has been applied successfully to explain all the FE data observed for E 〈 8.SV/μm.展开更多
Banana bunchy top virus (BBTV) is one of the most severe and widespread virus limiting production and distribution of planting material of banana (Musa spp.) crops in the world. In Democratic Republic of Congo (DRC), ...Banana bunchy top virus (BBTV) is one of the most severe and widespread virus limiting production and distribution of planting material of banana (Musa spp.) crops in the world. In Democratic Republic of Congo (DRC), these crops play a major role in daily life of almost 70% of citizen. Many factors influence banana production negatively such as Banana bunchy top disease. Epidemiological survey was conducted in experimental stations and farmers’ fields for two consecutive seasons covering 72 sites in five provinces of south western of RDC. The objective of this study was to evaluate the presence and distribution of the Banana bunchy top virus in five provinces of South Western of DRC, with emphasis on the agro-ecological factors. A total of 174 Musa spp. leaves samples were collected and analyzed by PCR. The results revealed the presence of BBTV in all provinces investigated. The frequency of BBTV was 6.3% in Bandundu, 12.1% in Kasa?Oriental, 17.8% Bas Congo, 1.1% in Katanga and 7.5% Kinshasa Urban and Peri-urban. Results also revealed that BBTV occurred in experimental station and farmers’ fields, both having all cooking and dessert bananas. The high prevalence of BBTV seemed to be linked to multiple introductions of planting materials in the Bas Congo province during 1990 and 2002. However, the province of Katanga had not experienced the introduction of planting material. This factor would explain the lowest prevalence of Banana bunchy top virus in this province. The results indicated that there was a real need to facilitate access to genetically improved and healthy certified planting material in these provinces.展开更多
Banana bunchy top virus(BBTV)poses a serious danger to banana crops worldwide.BBTV-encoded protein B4 is a determinant of pathogenicity.However,the relevant molecular mechanisms underlying its effects remain unknown.I...Banana bunchy top virus(BBTV)poses a serious danger to banana crops worldwide.BBTV-encoded protein B4 is a determinant of pathogenicity.However,the relevant molecular mechanisms underlying its effects remain unknown.In this study,we found that a functional peptide could be liberated from protein B4,likely via proteolytic processing.Site-directed mutagenesis indicated that the functional processing of protein B4 is required for its pathogenic effects,including dwarfism and sterility,in plants.The released protein fragment targets host proteins,such as the large subunit of RuBisCO(RbcL)and elongation factor 2(EF2),involved in protein synthesis.Therefore,the peptide released from B4(also a precursor)may act as a non-canonical modifier to influence host-pathogen interactions involving BBTV and plants.展开更多
Banana bunchy top virus (BBTV),family Nanaviridae,genus Babuvirus,is a single stranded DNA virus (ssDNA) that causes banana bunchy top disease (BBTD) in banana plants.It is the most common and most destructive of all ...Banana bunchy top virus (BBTV),family Nanaviridae,genus Babuvirus,is a single stranded DNA virus (ssDNA) that causes banana bunchy top disease (BBTD) in banana plants.It is the most common and most destructive of all viruses in these plants and is widespread throughout the Asia-Pacific region.In this study we isolated,cloned and sequenced a BBTV sample from Hainan Island,China.The results from sequencing and bioinformatics analysis indicate this isolate represents a satellite DNA component with 12 DNA sequences motifs.We also predicted the physical and chemical properties,structure,signal peptide,phosphorylation,secondary structure,tertiary structure and functional domains of its encoding protein,and compare them with the corresponding quantities in the replication initiation protein of BBTV DNA1.展开更多
The DNA was isolated from banana bunchy top virus （BBTV） in Guangzhou areas and a l.lkb DNA of replicas of BBTV was obtained by PCR using this virus DNA as templates for amplification. This reformed DNA of the BBTV ...The DNA was isolated from banana bunchy top virus （BBTV） in Guangzhou areas and a l.lkb DNA of replicas of BBTV was obtained by PCR using this virus DNA as templates for amplification. This reformed DNA of the BBTV replicas which being homologous to 90% with the Australia＇s encoded the C-Terminal of BBTV replicas. The reformed BBTV replicas were cloned to pBI121 in the position between CaMV 35S promoter and NOS termination sequence, and a plant-expressed carder was established. Four transgenic bananas with the expression of BBTV replicase gene in To generation were detected with PCR and Western blot analysis. The ability of these transgenic bananas against bunchy top virus is being analyzed.展开更多
文摘Banana bunchy top virus Chinese Zhangzhou isolate (BBTV-ZZ) DNA 4 was amplified by PCR and cloned. Sequence analysis showed that BBTV-ZZ DNA 4 is 1 039 nucleotides (nts) in length and this virus could be one member of BBTV Asian group. Transcriptional initiation site A, which is at the 269 nucleotide, was preliminarily determined by using 5' RACE method. BBTV-ZZ DNA 4 non-coding region was sub-cloned by PCR and inserted into upstream of gfp : : gus plant expression vector pCAMBIA 1304 to construct recombinant plasmid pTA2. Agrobacterium tumefaciens harboring pTA2 was injected into leaves of the tobacco (Nicotiana tabacum L. cv. Xanthi NC) via Agrobacterium-infiltration procedure. Transient expressions of GUS and GFP were determined in injected leaves 3 - 5 d later. GUS activities of pTA2, pCAMBIA 1304 injected and non-injected tobacco leaves respectively were 1.007 0 pmol MU(.)mug(-1.)min(-1), 2.069 0 pmol MU(.)mug(-1.)min(-1) and 0.021 4 pmol MU(.)mug(-1.)min(-1). Indirect ELISA for GFP in 1 mg total protein from pTA2, pCAMBIA 1304 injected and non-injected leaves showed an A(490 nm) value of 89.577, 100.440 and 3.287, respectively. These results showed that the non-coding region of BBTV-ZZ DNA 4 has a promoter activity not only in the virus replication in monocot, but also in driving the expression of a foreign gene in dicot plants.
基金supported by the Shanghai Education Committee of China(Grant No 07ZZ95)
文摘This paper reports that bunchy flake-like nano-graphite crystallite films （BNGCFs） were deposited on Si substrates by using the microwave chemical vapour deposition technique. Furthermore the BNGCFs were characterized by x-ray diffraction spectra, scanning electron microscopy, Raman spectra and field emission （FE） I-V measurements, and a lowest turn-on field of 1.5 V/μm, and a high average emission current density of 30 mA/cm2 at a macroscopic electric field of 8.0V/μm were obtained. The J-E data did not follow the original Fowler-Nordheim （F-N） relation since they were not well represented in the F-N plot by a straight line. A model considering the F-N mechanism, and the statistic effects of FE tip structures has been applied successfully to explain all the FE data observed for E 〈 8.SV/μm.
文摘Banana bunchy top virus (BBTV) is one of the most severe and widespread virus limiting production and distribution of planting material of banana (Musa spp.) crops in the world. In Democratic Republic of Congo (DRC), these crops play a major role in daily life of almost 70% of citizen. Many factors influence banana production negatively such as Banana bunchy top disease. Epidemiological survey was conducted in experimental stations and farmers’ fields for two consecutive seasons covering 72 sites in five provinces of south western of RDC. The objective of this study was to evaluate the presence and distribution of the Banana bunchy top virus in five provinces of South Western of DRC, with emphasis on the agro-ecological factors. A total of 174 Musa spp. leaves samples were collected and analyzed by PCR. The results revealed the presence of BBTV in all provinces investigated. The frequency of BBTV was 6.3% in Bandundu, 12.1% in Kasa?Oriental, 17.8% Bas Congo, 1.1% in Katanga and 7.5% Kinshasa Urban and Peri-urban. Results also revealed that BBTV occurred in experimental station and farmers’ fields, both having all cooking and dessert bananas. The high prevalence of BBTV seemed to be linked to multiple introductions of planting materials in the Bas Congo province during 1990 and 2002. However, the province of Katanga had not experienced the introduction of planting material. This factor would explain the lowest prevalence of Banana bunchy top virus in this province. The results indicated that there was a real need to facilitate access to genetically improved and healthy certified planting material in these provinces.
基金supported by grants from the Natural Science Foundation of China (No. 31301641 to J.Z.)the Program for Qualified Personnel of Taiwan Strait West Coast (No. K8812007 to L.H.X.)
文摘Banana bunchy top virus(BBTV)poses a serious danger to banana crops worldwide.BBTV-encoded protein B4 is a determinant of pathogenicity.However,the relevant molecular mechanisms underlying its effects remain unknown.In this study,we found that a functional peptide could be liberated from protein B4,likely via proteolytic processing.Site-directed mutagenesis indicated that the functional processing of protein B4 is required for its pathogenic effects,including dwarfism and sterility,in plants.The released protein fragment targets host proteins,such as the large subunit of RuBisCO(RbcL)and elongation factor 2(EF2),involved in protein synthesis.Therefore,the peptide released from B4(also a precursor)may act as a non-canonical modifier to influence host-pathogen interactions involving BBTV and plants.
基金The Central Level,Scientific Research Institutes for Basic R & D Special Fund Business(ITBB110303)
文摘Banana bunchy top virus (BBTV),family Nanaviridae,genus Babuvirus,is a single stranded DNA virus (ssDNA) that causes banana bunchy top disease (BBTD) in banana plants.It is the most common and most destructive of all viruses in these plants and is widespread throughout the Asia-Pacific region.In this study we isolated,cloned and sequenced a BBTV sample from Hainan Island,China.The results from sequencing and bioinformatics analysis indicate this isolate represents a satellite DNA component with 12 DNA sequences motifs.We also predicted the physical and chemical properties,structure,signal peptide,phosphorylation,secondary structure,tertiary structure and functional domains of its encoding protein,and compare them with the corresponding quantities in the replication initiation protein of BBTV DNA1.
基金This work was supported by Guangdong Natural Science Foundation in China.
文摘The DNA was isolated from banana bunchy top virus （BBTV） in Guangzhou areas and a l.lkb DNA of replicas of BBTV was obtained by PCR using this virus DNA as templates for amplification. This reformed DNA of the BBTV replicas which being homologous to 90% with the Australia＇s encoded the C-Terminal of BBTV replicas. The reformed BBTV replicas were cloned to pBI121 in the position between CaMV 35S promoter and NOS termination sequence, and a plant-expressed carder was established. Four transgenic bananas with the expression of BBTV replicase gene in To generation were detected with PCR and Western blot analysis. The ability of these transgenic bananas against bunchy top virus is being analyzed.
