RESUMO
Canine distemper virus (CDV) neutralizing antibody (NT) titer was examined against the sera from 7 giant pandas aged between 8 to 21 years housed at Chengdu Research Base of Giant Panda Breeding,China.Anti-CDV NT titer against the Onderstepoort strain showed a wide range from × 2 to×256 (median=16),even though the ani-mals had been receiving an attenuated live vaccine made from an anonymous domestic CDV strain twice a year since 2003.A single administration of attenuated morbillivirus antigen often be enough to give corresponding host a steady immunogenicity.Anti-CDV-NT variation in the giant panda suggests some deficiency in the relationship between the vaccine and the host.
RESUMO
Using oligonucleotide primers designed to match hypervariable segments I (HVS-1) of Panthera tigris mitochondrial DNA (mtDNA), we amplified two different PCR products (500 bp and 287 bp) in the tiger (Panthera tigris), but got only one PCR product (287 bp) in the leopard (Panthera pardus). Sequence analyses indicated that the sequence of 287 bp was a D-loop-like nuclear mitochondrial sequence (Numts), indicating a nuclear transfer that occurred approximately 4.8-17 million years ago in the tiger and 4.6-16 million years ago in the leopard. Although the mtDNA D-loop sequence has a rapid rate of evolution, the 287-bp Numts are highly conserved; they are nearly identical in tiger subspecies and only 1.742% different between tiger and leopard. Thus, such sequences represent molecular 'fossils' that can shed light on evolution of the mitochondrial genome and may be the most appropriate outgroup for phylogenetic analysis. This is also proved by comparing the phylogenetic trees reconstructed using the D-loop sequence of snow leopard and the 287-bp Numts as outgroup.