A molting rhythm for serum proteins of the cockroach, Blatta orientalis.

Zoology Department, University of Massachusetts, Amherst 01002.
Comparative biochemistry and physiology. B, Comparative biochemistry (Impact Factor: 2.07). 02/1978; 60(3):333-7. DOI: 10.1016/0305-0491(78)90110-4
Source: PubMed

ABSTRACT 1. Polyacrylamide gel electrophoresis (PAGE) in 4% gels of Blatta orientalis larval hemolymph revealed 4 major proteins. 2. Maximum incorporation of [14C]-leucine into total hemolymph protein occurs within 24 hr and is followed by negligible turnover in the next 24 hr. 3. Quantitative PAGE was used to monitor concentration changes during the molting cycle in synchronously molting cultures. 4. All 4 proteins show the same temporal rhythm of variation but different amplitudes. 5. The widely differing concentrations achieved are accounted for by different rates of synthesis.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The clearance of exogenously administered proteins from the haemolymph of larval Blatta orientalis was measured during the intermoult and at ecdysis. Two large proteins, radiolabelled B. orientalis larval-specific protein (Mr = 508,000; Rs = 68 Angs), and E. coli β-galactosidase (Mr = 464,000; RS = 69 Angs) and a smaller protein, radiolabelled bovine serum albumin (Mr = 66,300; Rs = 53 Angs), were injected into the haemolymph and their clearances measured at various times during the moulting cycle. During the intermoult, [3H]bovine serum albumin was rapidly cleared (T1/2= 4.5 h) while [14C]larval-specific protein and β-galactosidase showed no detectable depletion from the haemolymph in 49 h. In moulting animals, however, both high-Mr proteins were rapidly cleared (larval-specific protein, T12 = 41 h; β-galactosidase, T1/2= 9.2 h). The T1/2 for depletion of endogenous larval-specific protein at moulting is approx. 24 h. These data suggest that cockroach haemolymph proteins remain confined and accumulate within the haemolymph during the intermoult because of their large size, but during moulting the size barrier no longer functions and the haemolymph is depleted of proteins. Neither the size barrier nor the clearance mechanism exhibit pronounced protein specificity since both mechanisms are responsive to foreign proteins as well as homotypic proteins.
    Journal of Insect Physiology 01/1987; 33:155-158. · 2.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The 18S and 33S vitellins (Vts) of Blattella germanica were subjected to periodate oxidation and digestions with α-mannosidase, endo-β-Nacetylglucosaminidase H (endo-H), and trypsin to study their effects on Vt structure and function. Periodate oxidation caused 33S Vt to dissociate to a form that cosedimented with 18S Vt upon glycerol gradient centrifugation but had no effect on the sedimentation of 18S Vt. This result implicates the oligosaccharides in stabilization of the 33S structure. Incubation of 18S and 33S Vts with α-mannosidase and endo-H revealed that the oligosaccharides of both Vts are largely shielded from attack by both glycosidases. However, the carbohydrate of 18S Vt was 3 to 5 times more susceptible to both enzymes, suggesting that the 18S to 33S transition results in decreased accessibility of the oligosaccharides to both glycosidases. Short-term exposure of 18S and 33S Vts to trypsin resulted in limited hydrolysis; the Mr 102,000 subunit of each form was cleaved with an Mr79,000 peptide as a major product. However, the sedimentation properties of the Vts and their relative susceptibilities to α-mannosidase were unchanged; therefore while the Mr102,000 subunit of the Vt is vulnerable to trypsin, it retains its higher-order structure after limited digestion. Endocytosis of radiolabelled 18S Vt by oocytes in vivo decreased about 15-fold after its modification by periodate and sixfold after treatment with α-mannosidase. Limited trypsin digestion also severely diminished its uptake. All injected radioactivity of unmodified 18S and 33S Vts could be recovered from either the hemolymph or ovaries of recipient females. However, modified Vts were taken up from the hemolymph primarily by cells of the pericardium and the fat body, suggesting that these organs participate in a clearance mechanism that recognizes “damaged” Vt molecules.
    Archives of Insect Biochemistry and Physiology 01/1988; 9(3):179-199. · 1.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The hemimetabolous type of metamorphosis, as exemplified by the cockroach, is, in many respects, a minimal model of metamorphosis. The ecology of the larva and adult is often quite similar, and most of the functional larval tissues continue to be functional in the adult. The metamorphosis is often described as 'incomplete' or 'gradual'. A transition stage between immature and adult, the nymph, is distinguished by some investigators in specific groups of hemimetabolous insects. The use of the term 'nymph' is useful. The nymph, as opposed to a larva in general, has developed wing pads and in some groups, including the cockroaches, is diagnostic of the fact that metamorphosis will occur with the next molt. The last instar larval cockroach will be called a nymph, while retaining the more traditional term 'penultimate larva' for the next to last larval instar. The nymph stage has been given special meaning and formalized with relation to the caste system in the termites, immunologically close relatives of the cockroach. The termite nymph has already undergone some metamorphic changes and is restricted in its developmental potencies; it is capable of becoming a functional reproductive but not a soldier as shown by Wilson in 1975.
    Current Topics in Insect Endocrinology and Nutrition. 07/1981;