Purification and characterisation of a calcium-independent lectin (PjLec) from the haemolymph of the shrimp Penaeus japonicus.
A natural lectin (nominated PjLec) was isolated from haemolymph of the shrimp Penaeus japonicus by affinity chromatography with fetuin-Sepharose. The result of SDS-PAGE showed that the purified PjLec protein consisted of 37kDa subunits. The native PjLec behaved as a 452kDa protein in gel filtration chromatography. Those data suggest that PjLec is composed of 12 subunits of similar molecular weight. PjLec has a broad spectrum of bacterial-agglutination activities against both Gram-positive and Gram-negative bacteria, including two Vibrio species and two other strains pathogenic for shrimp. In addition, PjLec could agglutinate all the vertebrate erythrocytes tested, and the haemagglutination was calcium-independent. The haemagglutination of PjLec was inhibited by ManNAc, Neu5A and lipopolysaccharide. Bovine submaxillary mucin, which contains mainly Neu5A, was the most potent inhibitor of PjLec (MIC of 0.0006mgml(-1)). The haemagglutination activity of PjLec was stable between pH 6 and pH 8, and was temperature-dependent. Our results suggested that PjLec may be an important humoral defence factor against bacterial infection in P. japonicus.
Yang
Haijie
H
College of Oceanography and Environmental Science, Xiamen University, Xiamen 361005, PR China. hjyang_wmd@hotmail.com
Luo
Tian
T
Li
Fang
F
Li
Shaojing
S
Xu
Xun
X
D000372:Agglutination Tests; D000818:Animals; D001419:Bacteria / Q000276:immunology; D002118:Calcium / Q000502:physiology; D002847:Chromatography, Agarose / Q000662:veterinary; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006458:Hemolymph / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000302:isolation & purification* / Q000502:physiology*; D008297:Male; D008970:Molecular Weight; D033561:Penaeidae / Q000276:immunology* / Q000382:microbiology; D013696:Temperature; D000509:alpha-Fetoproteins / Q000737:chemistry / Q000378:metabolism
D037102:Lectins; D000509:alpha-Fetoproteins; D002118:Calcium