Expression of collagenase in Flavobacterium psychrophilum isolated from cold-water disease-affected ayu (Plecoglossus altivelis).
The collagenase activity and the fpcol gene were examined in Flavobacterium psychrophilum isolates from cold-water disease (CWD)-affected ayu, Plecoglossus altivelis. Collagenase expression was closely related to the accumulated mortality of CWD-affected ayu. RT-qPCR and bacterial challenge experiments showed that F. psychrophilum ayu isolate WA-1 expressed the fpcol gene more actively and was more virulent than ayu isolate WA-2. The amago (Oncorhynchus masou) isolate WB-1, which possesses a pseudo-fpcol gene, was not harmful to ayu. Hitherto, the well-studied metalloproteases Fpp1 and Fpp2 have been considered virulence factors. However, the most virulent isolate against ayu (WA-1) showed no Fpp activity because of a deletion mutation or an insertion of a transposon in the fpp genes. The less virulent WA-2 isolate showed only Fpp1 activity. Taken together, these results suggest that collagenolytic activity, but not Fpp activity, is related to the virulence of F. psychrophilum isolates in CWD-affected ayu.
a Department of Freshwater Fisheries , Wakayama Prefectural Fisheries Experimental Station , Wakayama , Japan.
Hitoshi
H
Nakayama
b Nippi Research Institute of Biomatrix , Toride , Japan.
Keisuke
K
Tanaka
b Nippi Research Institute of Biomatrix , Toride , Japan.
Naoko
N
Teramura
b Nippi Research Institute of Biomatrix , Toride , Japan.|c Japan Institute of Leather Research , Tokyo , Japan.
Shunji
S
Hattori
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003080:Cold Temperature; D017364:Collagenases / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements; D005393:Fish Diseases / Q000382:microbiology; D045826:Flavobacteriaceae Infections / Q000382:microbiology / Q000662:veterinary*; D005417:Flavobacterium / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D015870:Gene Expression; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D017683:Oncorhynchus / Q000382:microbiology; D036441:Osmeriformes / Q000382:microbiology*; D011544:Pseudogenes; D014774:Virulence
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D045726:Metalloproteases; D017364:Collagenases
Flavobacterium psychrophilum; cold-water disease; collagenase; metalloprotease; virulence factor