Lipid of white-spot syndrome virus originating from host-cell nuclei

The hypothesis that white-spot syndrome virus (WSSV) generates its envelope in the nucleoplasm is based on electron microscopy observations; however, as yet there is no direct evidence for this. In the present study, the lipids of WSSV and the nuclei of its host, the crayfish Procambarus clarkii, were extracted and the neutral lipid and phospholipid contents were analysed by high-performance liquid chromatography, thin-layer chromatography and gas chromatography/mass spectrometry. Phosphatidylcholine (PC) and phosphatidylethanolamine comprised 62.9 and 25.8 %, respectively, of WSSV phospholipids, whereas they comprised 58.5 and 30 %, respectively, of crayfish nuclei phospholipids. These two phospholipids were the dominant phospholipids, and amounts of other phospholipids were very low in the total WSSV and crayfish nuclei phospholipids. The data indicate that the phospholipid profile of WSSV and crayfish nuclei are similar, which is in agreement with the model that the lipids of WSSV are from the host-cell nuclei. However, the fatty acid chains of PC were different between the WSSV virions and crayfish nuclei, and the viral neutral lipid component was also found to be somewhat more complicated than that of the host nuclei. The number of species of cholesterol and hydrocarbon in virus neutral lipid was increased compared with that in host-cell nuclei neutral lipid. It is suggested that the differences between WSSV and its host are either due to selective sequestration of lipids or reflect the fact that the lipid metabolism of the host is changed by WSSV infection.

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Effect of white spot syndrome virus (WSSV) infection on immune enzyme activity and ultrastructure in the haemolymph tissue of Cherax quadricarinatus (Decapoda, Astacidea)

Crustaceana ◽

10.1163/15685403-00003550 ◽

2016 ◽

Vol 89 (6-7) ◽

pp. 669-684

Author(s):

J. J. Ning ◽

M. M. Zhang ◽

Q. Q. Tong ◽

X. Cao ◽

D. L. Wang ◽

...

Keyword(s):

Enzyme Activities ◽

White Spot Syndrome Virus ◽

White Spot ◽

Immune Protection ◽

Cell Nuclei ◽

Cherax Quadricarinatus ◽

Deformation And Fracture ◽

Before And After ◽

Protection Rate ◽

White Spot Syndrome

To explore the pathogenic mechanism of white spot syndrome virus (WSSV) in crayfish (Cherax quadricarinatus), we analysed activities of the three immune-related enzymes PO, SOD and LSZ in haemolymph tissue ofC. quadricarinatusbefore and after infection, and simultaneously studied the ultrastructural pathology. The results show that WSSV infection affects activities of the three enzymes. After 6-24 h of WSSV infection, the activities of PO, SOD and LSZ increased, but decreased significantly during longer infection times. The enzyme activities in WSSV-infected crayfish were significantly lower than those in controls at 72 h, except for LSZ (). Interestingly, the activities of PO, SOD and LSZ in the group treated with immune-polysaccharides before challenge with WSSV were higher than in the directly infected group, and the immune protection rate reached 51.9%, suggesting that the polysaccharides could improve enzyme activities and enhance antiviral defences of the organism. Ultrastructural pathological changes showed damaged haemolymph tissue, deformed golgiosomes, fuzzy damage in the mitochondrial structures, and nuclear membrane deformation and fracture. High levels of heterochromatin appeared in the nucleus; organoid and chromatin dissolved in dying blood cells, cytoplasm appeared oedematous and cells dissolved. WSSV particles were visible in blood cell nuclei of infected crayfish.

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