Zhan Wenbin

Histopathological Observation of Lymphocystis Disease and Lymphocystis Disease Virus (LCDV) Detection in Cultured Diseased Sebastes schlegeli

Lymphocystis nodules occurring in the cultured sting fish Sebastes schlegeli were observed under light and electron microscope. Lymphocystis disease virus (LCDV) in the tissues of diseased fish was detected with indirect immunofluorescence test (IFAT). Results showed that lymphocystis cells had overly irregular nuclei, basophilic intracytoplasmic inclusion bodies with virions budding from the surface, and hyaline capsules outside the cell membrane. Numerous virus particles about 200 nm in diameter scattered in the cytoplasm, electron-dense particles 70–80 nm in diameter filled in perinuclear cisterna, and membrane-enveloped particles with electron-dense core of 70–80 nm appeared around cellular nucleus. IFAT using monoclonal antibody against LCDV from Paralichthys olivaceus revealed that specific green fluorescence was present in the cytoplasm of lymphocystis cells, epithelium of stomach, gill lamellae, and muscular fibers under epidermis of S. schlegeli, just as that in the cytoplasm of lymphocystis cells of P. olivaceus, suggesting the presence of LCDV in these tissues.

Detection of white spot syndrome virus (WSSV) ofPenaeus chinensis by in situ hybridization

White Spot Syndrome Virus (WSSV) was purified from hemolymph of infected shrimp. After nucleic acid extraction from the purified virus particles, EcoR I-digested fragments of the WSSV genome were cloned; three of these fragments were used as non-radioactive probes labeled with DIG-11-dUTP. The probes hybridized in situ, with sections located in the nuclei of all WSSV-infected tissues. The virus was detected in the gill, stomach, epidermis, and connective tissue and so on, but not detected in healthy shrimp tissues and epithelial cells of hepatopancreatic tubules of diseased shrimp.

The gastric shield and the underlying epithelium ofChlamys farreri: Morphological, histological and histochemical characterizations

The gastric shield and underlying stomach epithelium ofChlymas farreri were examined at the light and ultrastructural levels. The results showed that the gastric shield consisted of two different size lobes joined together by a narrow middle piece, the thicker lobe was shaped like a funnel, but unclosed at the lateral side; the other lobe was irregularly triangular-shaped. The transverse section of the thicker lobe was obviously laminated and gradually decreased in thickness from the peak to the margins of the shield. The underlying epithelium bore numerous about 3μm diameter spherical processes formed by the apical plasmalemma of the epithelial cells becoming blunt pseudopodia. Microvilli and some interspersed cilia were present in the areas among the spherical processes regions where only microvilli existed. Rough endoplasmic reticulum, Golgi apparatus, different-sized electron-dense secretory granules and electron-lucent vacuoles as well as abundant mitochondria were present in the underlying epithelial cells. Fused droplets of the secretion from the underlying epithelial cells formed the gastric shield.