Investigation of the structure of equine articular cartilage link protein (LP) from individuals ranging in age from 1 to 15 years identified 3 distinct isoforms having molecular weights of 46,000, 43,000, and 41,000. The relative amounts of each of the 3 isoforms altered with age. The largest form did not change with age; however, amounts of the Mr 43,000 and 41,000 forms increased with increasing age. The results suggested that an accumulation, in the extracellular matrix of cartilage, of these 2 smaller products may have arisen from proteolytic cleavage. The complete amino acid sequence of the protein core was determined from complementary DNA products prepared by polymerase chain reaction amplification of cartilage LP mRNA. The sequence had 96% similarity with human LP and with that of other species for which the primary structure has been determined. This high degree of sequence conservation and the isoform data indicate that extracellular processing of LP occurs by similar mechanisms in various species. At the transcription level, equine chondrocytes were found to express LP as 2 abundant mRNA of 5.0 and 3.0 kb, and a smaller mRNA of 1.5 kb. Processing of the LP mRNA in horses, thus, appears to be similar to that found in other species investigated, and although multiple transcripts are present, the coding region remains unaltered and only 1 protein product is made.

In order to obtain the genetic informations of the Korean isolates of porcine circovirus 2 (PCV2), nucleotide sequences of total genome of three isolates and open reading frame 2 (ORF2) of four isolates were determined and compared with those of other reference PCV2 isolates. Nucleotide sequences of 3 isolates showed over 99% homology with those of reference strain (GenBank accession no. AF027217). Point mutations were mainly determined on ORF2 regions but little on ORF1 regions.

Canine hepatozoonosis isa growing tick-borne disease in Punjab.Two canine hepatozoonosis cases, oneclinical and one subclinical, in Punjabwere analyzed by PCR targeting 18S rRNAgene (666 bp). After sequence analysisof the PCR products, both of them werefound almost identical to each other andwere closely related to the Hepatozooncanis strain found in Saint kitts and Nevisand Brazil with 100% (442/442) and 99%(440/442) nucleotide identity respectively.Isolates from Malta and Philippines ofH. canis were distantly related to IndianH. canis with 437/442 and 436/442 matchidentities. These results suggest that H.canis detected in north Indian dogs mighthave closer ancestral relationship with SaintKitts and Nevis followed by Brazil strain.This is the first molecular characterizationof Hepatozoon from Punjab, India.

Akabane disease is caused by an arthropod-borne viral pathogen and leads congenital abnormalities of the central nervous system in infected ruminants. One isolate, KV0505, showed cytopathic effect in Vero cells. The KV0505 isolate was obtained from plasma, which was collected from a cattle raised on Jeju Island in May 2005. Jeju Island is located near the southern part of the Korean peninsula. The isolate was confirmed as Akabane virus (AKAV) by immunofluorescence assay using AKAV specific monoclonal antibodies and reverse transcription polymerase chain reaction (RT-PCR). Suckling mice inoculated with the isolate showed signs of paralysis and died within 10 days post-inoculation. Comparisons of the KV0505 N gene sequence with 39 other known AKAV strains revealed nucleotide homologies ranging from 83.6% (MP496 strain) to 99.7% (M171 strain). When compared with the K-9 strain, which was isolated from a cow in Korea in 1994, the nucleotide sequence homology with the N gene was 99.7%. Thus, genes of the KV0505 isolate were closely related to those of the M171 strain, which were clustered into the Ic group of AKAV.

The cDNA of the aquabirnavirus, GC-1 isolated from rockfish Sebastes schlegeli in Korea, was synthesized using the reverse transcriptase-polymerase chain reaction. The nucleotide and deduced amino acid sequences were determined from cDNA of the VP2-NS-VP3 coding region of genome segment A. The nucleotide sequences of the segment A were 3,086 base pairs (bp) in length and contained large open reading frame (ORF) and terminal sequences. The large ORF was comprised of 2,916 bp nucleotides and composed of 972 deduced amino acid sequences. Pairwise comparisons were made with other aquabirnavirus sequences published previously. The study of genetic relationships between GC-1 and aquabirnaviruses in the large ORF and VP2 coding regions demonstrated that the GC-1 has the nearest genetic relationship with the marine birnaviruses (MABV strains), and the GC-1 and MABV strains can be clustered as the same genogroup. GC-1 can be included in MABV, which is the 7th genogroup of family Aquabirnaviridae.

While the C-terminal cytoplasmic tail of anion exchanger 1 (AE1, band 3) has been reported to possess important physiological roles, including one for proper membrane trafficking, its precise characteristics remain unclear. To clarify the overall structural consequences of the conserved sequence EL(K/Q)(L/C)LD(A/G)DD, containing the core binding sequence LDADD for carbonic anhydrase II, in the C-terminal region, we analyzed the membrane expression and turnover of bovine AE1 with a series of truncation and substitution mutations in HEK293 cells. Immunofluorescence microscopy and cell-surface biotinylation demonstrated that truncation mutants missing 18 C-terminal residues targeted the plasma membrane, but the one lacking the conserved region, by truncation of 28 amino acid residues, was retained inside the cells. Substitutions of Ala for Glusup(901), Leusup(902), Leusup(905), and Aspsup(906) in the sequence E901L(K/Q)(L/C)LDADD909 of bovine AE1 or those in the corresponding murine sequence also caused intracellular retention, though these mutants had half-lives comparable to that for wild-type AE1. These data demonstrate that the conserved amino acid residues Glusup(1), Leusup(2), Leusup(5), and Aspsup(6) in the EL(K/Q)(L/C)LD(A/G)DD region have essential structural consequences in stable expression of AE1 at the plasma membrane regardless of the ability in binding to carbonic anhydrase II of this region.