Objective To clarify the distribution of hepatitis A virus (HAV) genotype in geographical regions of China Methods Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients...Objective To clarify the distribution of hepatitis A virus (HAV) genotype in geographical regions of China Methods Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients in different geographical regions Viral RNA was recovered from stool or serum by proteinase K digestion and phenol chloroform extraction, followed by ethanol precipitation prior to reverse transcription and polymerase chain reaction (RT PCR) amplification The nucleotide sequences of VP1/2A junction region were tested by using a direct sequencing technique Results A pairwise comparison of sequences within 168 bases at the VP1/2A junction revealed that all the sequences clustered within genotype Ⅰ About 53% of strains clustered in genotype ⅠB, with less than 6% variability; while the others clustered in genotype ⅠA, with less than 5 3% variability Sequence homology between genotype ⅠA and ⅠB varied from 88 7% to 92 3% Conclusion Epidemic or sporadic HAV strains in China may belong to HAV genotype ⅠA or ⅠB Epidemiologically related strains may be identical or closely related in sequence展开更多
The cry1Ah gene was one of novel insecticidal genes cloned from Bacillus thuringiensis isolate BT8. Two plant expression vectors containing cry1Ah gene were constructed. The first intron of maize ubiqutin1 gene was in...The cry1Ah gene was one of novel insecticidal genes cloned from Bacillus thuringiensis isolate BT8. Two plant expression vectors containing cry1Ah gene were constructed. The first intron of maize ubiqutin1 gene was inserted between the maize Ubiquitin promoter and cry1Ah gene in one of the plant expressing vectors (pUUOAH). The two vectors were introduced into maize immature embryonic calli by microprojectile bombardment, and the reproductively plants were acquired. PCR and Southern blot analysis showed that foreign genes had been integrated into maize genome and inherited to the next generation stably. The ELISA assay to T1 and T2 generation plants showed that the expression of Cry1Ah protein in the construct containing the ubi1 intron (pUUOAH) was 20% higher than that of the intronless construct (pUOAH). Bioassay results showed that the transgenic maize harboring cry1Ah gene had high resistance to the Asian corn borers and the insecticidal activity of the transgenic maize containing the ubi1 intron was higher than that of the intronless construct. These results indicated that the maize ubi1 intron can enhance the expression of the Bt cry1Ah gene in transgenic maize展开更多
文摘Objective To clarify the distribution of hepatitis A virus (HAV) genotype in geographical regions of China Methods Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients in different geographical regions Viral RNA was recovered from stool or serum by proteinase K digestion and phenol chloroform extraction, followed by ethanol precipitation prior to reverse transcription and polymerase chain reaction (RT PCR) amplification The nucleotide sequences of VP1/2A junction region were tested by using a direct sequencing technique Results A pairwise comparison of sequences within 168 bases at the VP1/2A junction revealed that all the sequences clustered within genotype Ⅰ About 53% of strains clustered in genotype ⅠB, with less than 6% variability; while the others clustered in genotype ⅠA, with less than 5 3% variability Sequence homology between genotype ⅠA and ⅠB varied from 88 7% to 92 3% Conclusion Epidemic or sporadic HAV strains in China may belong to HAV genotype ⅠA or ⅠB Epidemiologically related strains may be identical or closely related in sequence
基金the National Natural Science Foundation of China (Grant No. 30500039)National Basic Research Program of China (Grant No. 2003CB114201)Basic Scientific Research Foundation for Chinese Central Academy (Biotech-nology Research Institute, CAAS)
文摘The cry1Ah gene was one of novel insecticidal genes cloned from Bacillus thuringiensis isolate BT8. Two plant expression vectors containing cry1Ah gene were constructed. The first intron of maize ubiqutin1 gene was inserted between the maize Ubiquitin promoter and cry1Ah gene in one of the plant expressing vectors (pUUOAH). The two vectors were introduced into maize immature embryonic calli by microprojectile bombardment, and the reproductively plants were acquired. PCR and Southern blot analysis showed that foreign genes had been integrated into maize genome and inherited to the next generation stably. The ELISA assay to T1 and T2 generation plants showed that the expression of Cry1Ah protein in the construct containing the ubi1 intron (pUUOAH) was 20% higher than that of the intronless construct (pUOAH). Bioassay results showed that the transgenic maize harboring cry1Ah gene had high resistance to the Asian corn borers and the insecticidal activity of the transgenic maize containing the ubi1 intron was higher than that of the intronless construct. These results indicated that the maize ubi1 intron can enhance the expression of the Bt cry1Ah gene in transgenic maize
