title: Purification and characterization of lysozyme from hemolymph of Heliothis virescens larvae.
abstract: Lysozyme is an important antibacterial protein in the insect defense system. Lysozyme was isolated from hemolymph of Heliothis virescens larvae using gel filtration and ion-exchange chromatography. Heliothis lysozyme had a molecular mass of 16,000 daltons by SDS-PAGE. Using acid gel electrophoresis, Heliothis lysozyme migrated faster than egg white lysozyme. The pI of Heliothis lysozyme was estimated as greater than 9.5. Heliothis lysozyme had specific bactericidal activity against three Gram-positive bacteria but no activity against Escherichia coli. The bactericidal activity was stable at 100 degrees C at pH 3.0 after 60 min incubation, but was labile at 100 degrees C at pH 6.8 after 60 min incubation. Heliothis lysozyme was an inducible protein that increased 9 times when comparing unvaccinated with vaccinated larvae. Lysozyme from H. virescens was more similar in molecular mass, heat sensitivity and pH sensitivity to lysozyme isolated from Galleria mellonella and Bombyx mori than to lysozyme isolated from Hyalophora cecropia.
authors.affiliation: Department of Biology, Division of Molecular Sciences and Microbiology, The University of Memphis, Tennessee 38152, USA.
authors.forename: T D
authors.initials: TD
authors.lastname: Lockey
authors.forename: D D
authors.initials: DD
authors.lastname: Ourth
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D004926:Escherichia coli / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006458:Hemolymph / Q000201:enzymology*; D006358:Hot Temperature; D007814:Larva; D007915:Lepidoptera / Q000201:enzymology*; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D009113:Muramidase / Q000302:isolation & purification* / Q000378:metabolism* / Q000494:pharmacology; D013816:Thermodynamics
chemical_list: D000900:Anti-Bacterial Agents; D009113:Muramidase