共查询到20条相似文献，搜索用时 734 毫秒
1.
2.
3.
4.
5.
6.
7.
Infectious bursal disease viruses (IBDVs) in 26 IBDV-positive bursa samples collected in Croatia during the period 1996-2000 and in two commercially available vaccines were differentiated by the presence or absence of the CfoI, SacI, SspI, StuI, and TaqI restriction sites in the 422-bp fragment of segment A of the VP2 gene (nt 732-1153). The fragments from 14 (54%) field isolates were TaqI+ StuI+ SspI+ and SacI- CfoI-, indicating their very virulent (vv) character. The presence of CfoI restriction site in 10 (38%) field isolates is uncommon for vvIBDV strains. It was detected in only the 88180 vvIBDV strain. Nevertheless, these isolates can be classified as vv strains according to TaqI+ StuI+ SspI+ SacI- restrictions. Two SacI+ StuI+ CfoI+ TaqI- SspI- field isolates (8%) could be classified as non-vvIBDVs. The StuI+ restriction is common to vvIBDV strains. However, the StuI recognition sequence is present in the F52/70 classic European and 002-73 attenuated strains as well. The SacI+ CfoI+ StuI- SspI- restrictions and the lack of the TaqI restriction at nt position 832 show that the IBDV in GUMBOKAL IM-SPF vaccine corresponds to the attenuated and/or vaccine strains. The TaqI restriction at nt position 875 suggests that the IBDV in GUMBOKAL SPF vaccine could belong to the mild strains. 相似文献
8.
9.
10.
11.
J R Smiley S E Sommer D J Jackwood 《Journal of veterinary diagnostic investigation》1999,11(6):497-504
12.
13.
14.
15.
Molecular techniques have not only made timely and accurate detection of infectious bursal disease viruses (IBDVs) possible but also have allowed the identification of viral strains. Previously, we identified a genetic marker that distinguished wild-type IBDV strains from vaccine strains of the virus. The marker was an NgoM IV restriction enzyme site in the VP2 gene that was present in 10 wild-type viruses but not 16 vaccine strains of IBDV. On the basis of that study, we concluded that the NgoM IV marker could be useful in the identification of wild-type potentially pathogenic strains of this virus. Because virulent (hot) vaccine strains of IBDV are used to vaccinate commercial poultry, it was important to determine if the NgoM IV marker was present in these virulent vaccines. The infectious bursal disease Blen and Bursa Vac virulent vaccines were examined and determined to contain the marker. We concluded that the presence of this marker was not unique to wild-type strains of the virus. The absence of the NgoM IV marker, however, was consistent with some level of attenuation, and its presence appears to be consistent with virulent IBDV strains. 相似文献
16.
Tiwari AK Kataria RS Indervesh Prasad N Gupta R 《Comparative immunology, microbiology and infectious diseases》2003,26(1):47-53
In order to differentiate infectious bursal disease virus (IBDV) isolates/strains, a quick method of RT-PCR followed by restriction enzyme analysis of VP1 gene sequence is being reported for the first time. A 480 bp fragment, comprising one of the RNA dependent RNA polymerase motifs of VP1 gene sequence of an Indian classical virus, an attenuated vaccine strain, Georgia and two Indian field isolates, genetically similar to reported very virulent strains of IBDV, was amplified by RT-PCR. Restriction enzyme digestion of PCR products with Taq1 enzyme generated distinct profile for field isolates, different from the classical and attenuated viruses, whereas restriction profile with BstNI restriction enzyme was similar in all the viruses, irrespective of the pathotype. Therefore, the present results suggest that Taq1 digestion can be taken up for the differentiation of field isolates from the classical and vaccine strains. The sequence analysis of VPI gene of reported very virulent IBD viruses from Europe and Japan, using 'MapDraw' programme of Lasergene software, revealed similar restriction enzyme profile as in Indian field isolates. 相似文献
17.
18.
19.