Antigenicity of hypothetical protein HP33 of Vibrio harveyi Y6 causing scale drop and muscle necrosis disease in Asian sea bass.

A unique strain of Vibrio harveyi is the causative agent of scale drop and muscle necrosis disease (SDMND) in Asian sea bass (Lates calcarifer). This study investigated the protein profiles of SDMND-causing Vibrio harveyi isolates compared to the reference V. harveyi ATCC 14126 strain. A distinct protein band of 33 kDa, namely HP33, found from only V. harveyi SDMND was subjected to analysis by LC-MS/MS and the identified peptide sequences matched to an unknown hypothetical protein. Detection of HP33 coding sequence was investigated at both genomic and transcriptional levels and the results consistently supported the protein analysis. Recombinant HP33 protein was then produced using Escherichia coli system. The rHP33 protein did not cause mortality or visible clinical signs to Asian sea bass. However, the rHP33 protein was able to stimulate antibody response in Asian sea bass as evidenced by Western blotting and agglutination tests. Here, we proposed that rHP33 might be a good protein target for development of subunit vaccine and/or immunostimulant to protect Asian sea bass from SDMND.

Effects of anti-osteoporosis drugs against dexamethasone-induced osteoporosis-like phenotype using a zebrafish scale-regeneration model.

There are several animal models of glucocorticoid-induced osteoporosis (GIOP), but each requires a long time to evaluate drug effects. Zebrafish scales are classified as dermal bone and potentially represent a convenient animal model of GIOP because they rapidly regenerate following their removal. We clarified that dexamethasone-treated regenerating scales showed malformations, decreased size and circularity. Anti-osteoporosis drugs rescued the scale malformation phenotype eight-days following the removal of scales. Hence, the dexamethasone-induced regenerating scale malformation model may be a useful animal model for discovering drugs to treat GIOP.

DISSEMINATED OSSEOUS METAPLASIA OF THE VENTRAL SCALES OF A GRAY-BANDED KINGSNAKE ( LAMPROPELTIS ALTERNA).

A 22-yr-old, female gray-banded kingsnake ( Lampropeltis alterna) was examined for stomatitis and hard ventral scales. On examination, the ventral scales palpated as rigid and brittle. A blood sample yielded marked hypovitaminosis D (11 nmol/L). Radiographs revealed a generalized bone radiopacity outlining the ventral scales; scale biopsies were obtained for histologic examination and presented linear, superficial, and midzonal foci of well-differentiated dermal bone and bone marrow. The stomatitis was successfully treated, but the general condition of the snake declined, and it was euthanized. The most significant finding in the postmortem examination was abnormally pale kidneys. Histologic examination revealed diffuse renal gout and diffuse osseous metaplasia in the dermis of all of the ventral scales. Generalized osseous metaplasia of the ventral scales in snakes has not, to our knowledge, been reported; the cause in this report was not identified, but given the extensiveness of the lesion, it is likely that the cause was multifactorial.

Skin and scale regeneration after mechanical damage in a teleost.

Skin wound healing has been widely studied in mammalian models but the information on teleost cutaneous healing is sparse and frequently considered in the context of viral or bacterial infections or parasitic infestations in aquaculture. In the present study a detailed time course (0 h, 6 h, 1, 2, 3 and 4 days) coupled to morphology and gene expression analysis revealed rapid regeneration of skin without scarring in a marine teleost after a superficial wound caused by the loss of a large area of scales. The integrity of the integument, as assessed by quantification of extracellular matrix (ECM) gene transcripts (fn1a, colIα1, colVα2, colXα1, ogn1, ogn2, crtac1a, cyr61, pcna, krt2 and mmp9) was restored within 2 days. Epithelial-mesenchyme interactions assessed by expression of edar and shh were associated with epidermal closure, the re-establishment of the basement membrane and also scale eruption. Histological observations suggested tissue re-epithelialization was independent of inflammation and that transcripts representing the humoral and cellular elements of the immune response (mpo, cyba and csf1r, cd48 and cd200) were modulated in the early stages of sea bream (Sparus aurata) skin repair after injury. Overall, the results indicate that after superficial skin damage tissue reconstitution started immediately with re-epithelialization, followed by ECM deposition and finally tissue maturation, indicating that in the skin regenerative process, reconstitution of the physical barrier was the priority over other integument functions, including immune surveillance.