ANTIHEMOCYTIC SURFACE COMPONENTS OF XENORHABDUS-NEMATOPHILUS VAR DUTKI AND THEIR MODIFICATION BY SERUM OF NONIMMUNE LARVAE OF GALLERIA-MELLONELLA

Modifying the outer membrane of Xenorhabdus nematophilus var. dutki, by dissociating outer membrane proteins and extracting lipopolysaccharide, accelerated bacterial removal from the hemolymph of nonimmune Galleria mellonella larvae. Larval serum modified the bacterial surface which enhanced adhesion to hemocytes and accelerated the removal of X. nematophilus from the hemolymph. This was independant of phenoloxidase activity. X. nematophilus inhibited the conversion of prophenoloxidase to phenoloxidase but did not inhibit phenoloxidase activity. The sugars α-d-mannose, d-galactose, and N-acetyl-d-glucosamine decreased the attachment of surface modified X. nematophilus to hemocytes and slowed their removal from the hemolymph. Evidence is presented suggesting that humoral factors, with preotolytic, lysozyme, and carbohydrase activity, may alter the outer membrane of X. nematophilus, and represent antibacterial factors in insect hemolymph. © 1991.