Changes in the titer of the female‐predominant storage protein (81K) during larval and pupal development of the waxmoth, galleria mellonella

Abstract

The levels of an 81K storage protein in the waxmoth, Galleria mellonella, were monitored during the course of development using rocket immunoelectrophoresis. During the fifth and sixth larval stadia, 81K protein levels increased during feeding and growth but sharply declined at each larval molt. During the fifth and sixth stadia hemolymph levels of the 81K protein increased to about 1 and 2.5 mg/ml, respectively, with no discernible differences between levels in males and females. Neither the fat body nor the remainder of the carcass contained the 81K protein, indicating that the accumulation of this protein during the intermolt period was exclusively in the hemolymph and redistribution of the 81K protein into other tissues does not occur at the final two larval molts. During the seventh (final) larval stadium the absolute quantities of the 81K protein increased from 23 μg per insect to over 1,600 μg in females and to 300 μg in males. The hemolymph concentration of the 81K protein reached 28 mg/ml in females and 6 mg/ml in males with only low levels found in the remaining tissues. Shortly after pupal apolysis, marked by eyespot retraction, the fat body in both sexes rapidly and quantitatively sequestered the 81K protein from the hemolymph. The 81K protein in the hemolymph of both males and females rapidly dropped to nearly zero concentration by pupation. The 81K storage protein remained localized in the fat body cells after uptake occurred, even though the fat body cells disaggregate and reaggregate during metamorphosis. During pharate adult development the 81K storage protein disappeared from the fat body without entering the hemolymph. At adult eclosion 81K was virtually absent from the tissues of both males and females.

Storage hexamer utilization in Manduca sexta

“…Insolubility in PBS indicates that the particle-associated hexamerins are not hemolymph proteins but must instead be constituents of cells. This reinforces their identity, for the MtH's have been shown in several lepidopteran pupae to be stored primarily in the fat body (Tojo et al, 1978; Bean and Silhacek, 1988; Pan and Telfer, 1992), while ArH is the predominant storage protein in hemolymph (Kramer et al, 1980; Telfer et al, 1983; Pan and Telfer, 2001). …”

“…All four are consumed primarily during somatic tissue metamorphosis, but sexual differences in the quantity of a methionine-rich hexamerin synthesized by larvae suggest that hexamerins can also be targeted for the support of egg production (Tojo et al, 1981; Ryan et al, 1985B; Tojo et al, 1985; Bean and Silhacek, 1988). This possibility has been confirmed by differences in the timing of hexamerin consumption between one early and one late egg producing species (Pan and Telfer, 2001).…”

Equivalence of riboflavin-binding hexamerin and arylphorin as reserves for adult development in two saturniid moths

“…The question has also been raised by the finding in Actias luna that reproductive and somatic tissues do not discriminate between ArH and the methionine-rich hexamerin (MtH) as precursor reservoirs during metamorphosis (Pan and Telfer, 1996). Equivalence of the two was unexpected because the tendancy of MtH to be stored in much greater quantities by females than by males had suggested that it has evolved in particular for the support of egg formation (Tojo et al, 1980;Ryan et al, 1985;Bean and Silhacek, 1988).…”

Methionine-rich hexamerin and arylphorin as precursor reservoirs for reproduction and metamorphosis in female luna moths

“…The aromatic amino acid richness of ArH has, since its analogue calliphorin was first described by Munn et al (1967), been presumed to be important for the deposition and tanning of cuticle. And since MtH is in some Lepidoptera much more abundant in female pupae than in males Ryan et al, 1985;Bean and Silhacek, 1988), it has been supposed to enhance the synthesis of products such as vitellogenin, chorion, and accessory gland secretions (Ogawa and Tojo, 1981). In particular, disulfide linkages contribute to the structural integrity of the lepidopteran chorion (Kawasaki et al, 1971;Smith et al, 1971;Regier et al, 19781, and Ogawa and Tojo (1981) raised the possibility that chorionic cystine is derived for this purpose by metabolic conversion of methionine as it is released from MtH during adult development.…”