The neuro-endocrine control of protein metabolism in the migratory grasshopper, Melanoplus sanguinipes

In normal females, distinct fluctuations in the protein content of the fat body and haemolymph are evident during each gonotrophic period. These fluctuations partly reflect changes in the protein requirements of the developing oocytes. Almost one half of the total protein deposited in the mature ovary is sequestered during the final stages of vitellogenesis when protein accumulated in the fat body and haemolymph is rapidly depleted. Although similar amounts of protein are deposited in the ovary during the first and subsequent gonotrophic periods, significantly less extraovarian protein is present throughout the latter periods.The accumulation of large amounts of protein in the fat body and haemolymph of ovariectomized females suggests that most yolk protein is of extraovarian origin. As the total protein content of these insects is comparable to that of vitellogenic females, ovariectomy apparently has no immediate effect on protein synthesis.Allatectomy or cautery of the median neurosecretory cells (mNSC) prevents vitellogenesis. Although protein gradually accumulates in the fat body and haemolymph of allatectomized females, the total protein content of these insects is significantly lower than that of controls. Treatment of allatectomized females with juvenile hormone analogue leads to a temporary but significant increase in the protein content of the fat body. However, the subsequent decline in fat body protein is paralleled by a pronounced increase in the protein content of the ovary. These findings suggest that the corpora allata (CA) stimulate both yolk protein synthesis in the fat body and its uptake into the ovary. The total protein content of mNSC-cauterized females is less than that of allatectomized females. This observation supports the proposal that the mNSC have not only an allatotropic effect but also a direct effect on protein synthesis.     

Haemolymph vitellogenin,juvenile hormone,and oöcyte growth in the adult cockroach Nauphoeta cinerea during first pre-oviposition period

In the cockroach Nauphoeta cinerea the incorporation of a protein of low solubility into the oöcytes begins at day 5 of its adult life. An immunologically identical protein appears in the haemolymph two days earlier. The concentration of this protein, i.e. ‘vitellogenin’ in the haemolymph increases up to the onset of yolk incorporation into the oöcytes. During ovarian development no correlation could be detected between vitellogenin titre and several other parameters (ovary dry weight, length of the basal oöcytes, haemolymph protein concentration, body weight and age when ovulation occurred). In young females vitellogenin titre depends on the age, i.e. the volume of the corpora allata and hence on the presence and the titre of JH. During the period of egg maturation the total haemolymph protein concentration generally tends to drop while materials not precipitable by trichloracetic acid circulate at higher concentration after ecdysis and before ovulation.Early decapitation prevents vitellogenin synthesis and oöcyte growth, but when JH is applied to decapitated females, the normal vitellogenin titre is re-established, ovarian development, however, cannot be fully resumed. A dose-response curve shows that serial application of the hormone is much more effective than single large doses. Farnesylmethylester, a JH mimic, is about a hundred times less active, but more persistent than JH. Copulation seems to enhance the synthesis and release of endogenous JH, while food and water uptake are necessary to guarantee and optimal ovarian development. JH and high vitellogenin titre never restore ovarian development in females deprived of food and/or water or in those decapitated shortly after ecdysis.     

On the relative importance of juvenile hormone and vitellogenin for oöcyte growth in the cockroach Nauphoeta cinerea

The corpora allata of castrated females of Nauphoeta grow only very slightly and do not reach a volume greater than that of the glands of normal females during gestation. These small corpora allata are, however, active and are responsible for the synthesis of vitellogenin (female specific protein) in large amounts. Besides vitellogenin the other haemolymph proteins are also synthesized and accumulated in the haemolymph in much higher concentrations than in normal females. Implanted oöcytes grow in castrated as well as in normal females at about the same rate until the tenth day of the oöcyte maturation period. Thereafter they only grow in castrated females. If castrated and normal females are decapitated, their protein content decreases. At the same time the growth stimulating capacity of their haemolymph decreases at a much faster rate. If oöcytes are implanted in castrated and decapitated females after 4 days they cannot grow any more although the vitellogenin titre of the haemolymph is still much higher than it is at any time in normal females. It can be concluded that vitellogenin alone cannot induce oöcyte growth and that juvenile hormone is necessary as well for vitellogenin synthesis as for its incorporation into the oöcytes. However, in insects rich in vitellogenin juvenile hormone leads to a more rapid oöcyte growth than in insects containing only small amounts of this protein.     

Protein and lipid concentration in the haemolymph of Danais chrysippus. Linn

Proteins and lipids in the haemolymph in both the sexes of the Danais chrysippus has been observed during the first gonotropic cycle. The concentration fluctuations in these haemolymph metabolites are correlated with the physiological state of the insect. The total protein and lipid concentration in the haemolymph of unmated females have been found to be low than the concentration found for the normal females although it followed the same type of oscillations in the concentration as have been observed for normal females.     

Gene-controlled incorporation of haemolymph protein into the ovaries of Bombyx mori

The haemolymph protein concentration in Bombyx mori decreases normally by about one-fourth during pharate adult development. In females homozygous for the small egg gene, the concentration of haemolymph protein remained constant throughout the pupal and pharate adult stages. The sm gene does not influence the synthesis of vitellogenic female protein of pupal and pharate adult haemolymph (FP). Normal ovaries transferred to the haemocoele of sm females undergo normal vitellogenesis. In the absence of normal alleles of sm, the ovaries encounter difficulties in the incorporation of FP into their oöcytes from pharate adult haemolymph. These results suggest that an active translocation mechanism is involved in the transfer of haemolymph protein into the ovaries.     

Änderungen im muster der Haemolymphproteine von adulten Königinnen der Hummelart Bombus terrestris

The soluble proteins of haemolymph during the life cycle from adult bumblebee queens (Bombus terrestris) were separated by disk electrophoresis on polyacrylamide gels. Twenty-three fractions stainable with amido black were detected. Every phase of the bee's adult life is characterized by a specific pattern of haemolymph proteins.Newly emerged queens have a low haemolymph protein concentration which increases in the first 5 days to a maximum. The high concentration is probably connected with the synthesis of hibernation reserves. Before the beginning of hibernation the concentration of some protein fractions seems to decrease; the concentration of these fractions is low also after hibernation.During the spring the first oöcytes begin to grow and the activity of corpora allata, hypopharyngeal glands, and wax glands reaches a maximum at the time of starting nests. A large increase in the concentration of haemolymph proteins is correlated with the activity of these glands. This high concentration does not change during the whole egg-laying period; however, the concentration decreases to a minimum in old queens with degenerating ovaries.In the protein pattern of ovary homogenate we detected three fractions with an RF identical to haemolymph fractions. Investigations on queens parasitized with the nematode Sphaerularia bombi confirmed that these fractions are yolk material (vitellogenin) taken up by ovaries. In parasitized queens oöcytes do not grow and the fractions are of a much lower concentration than in nonparasitized queens with maturing eggs. Therefore it appears that the parasite injures primarily the corpora allata known to stimulate the synthesis of yolk protein.     

Vitellogenin induced in adult male Diploptera punctata by juvenile hormone and juvenile hormone analogue: Identification and quantitative aspects

The effect of the juvenile hormone analogue hydroprene on the appearance in the haemolymph of the yolk-protein precursor vitellogenin in male Diploptera punctata has been assessed using rocket immuno-electrophoresis. Vitellogenin was induced in a dose-dependent fashion, with a minimum dose of 10 μg hydroprene required for its appearance. Implantation of male corpora allata into male and female hosts also resulted in the appearance of vitellogenin in the haemolymph of the hosts, with females showing apparent greater sensitivity to the implantation.The identity of vitellogenin in male haemolymph was further confirmed using Ouchterlony double immunodiffusion and SDS polyacrylamide gel electrophoresis of immunoprecipitates. The electrophoretic pattern of immunoprecipitated haemolymph from females and hydroprene-treated males was similar, further confirming that the immunoprecipitable product was in fact vitellogenin.     

An electrophoretic study of proteins of the ovary,fat body,and haemolymph in the migratory grasshopper, Melanoplus sanguinipes

Electrophoretic separation of saline extracts from the ovary revealed 14 proteins. Twelve proteins were detected in the fat body, of which seven had electrophoretic mobilities identical to those in the ovary. Similarly, eight of 16 proteins in the haemolymph of vitellogenic females ahad electrophoretically identical counterparts in the ovary. As these proteins accumulate in the haemolymph of ovariectomized females, the findings suggest that most yolk proteins are synthesized in the fat body. Although most female haemolymph proteins are present in males, two of the predominant yolk protiens are absent and represent female-specific proteins.Although certain proteins accumulate in the haemolymph of allatectomized females, the major ovarian proteins are absent or present in low concentrations. However, 48 hr after allatectomized females are treated with a juvenile hormone analogue, the haemolymph protein pattern resembles that of a normal female. This suggests that the corpora allata stimulate the synthesis of female-specific and other vitellogenic proteins. The median neurosecretory cells (mNSC) are also necessary for synthesis of female-specific proteins. Furthermore, proteins which are present in allatectomized females are absent in mNSC-cauterized insects suggesting that the mNSC stimulate general protein synthesis.     

Structure,haemolymph titre,and regulatory effects of juvenile homone during ovarian maturation in Leucophaea maderae

Juvenile hormone (JH) synthesized and secreted in vitro by the corpora allata of mated adult Leucophaea maderae females was determined to be JH III (methyl-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate).The haemolymph titre of JH was determined during maturation of the terminal oöcytes in the first reproductive cycle of L. maderae. In virgin females, JH is not detectable in the haemolymph during the first eight days following adult emergence; however, by 10 days after emergence, trace quantities of JH are apparent. Mating stimuli induce a dramatic increase in the concentration of haemolymph JH, with a peak occurring approximately 12 days after mating; thereafter, the JH concentration declines until it has reached an undetectable level 19 days after mating, at the time of chorion deposition.During ovarian maturation, changes in the rates of synthesis of vitellogenin by the fat body and DNA by the ovary correlate closely with the haemolymph titre of JH. However, no such correlation exists between the JH titre and the extensive ovarian protein synthesis that occurs in L. maderae coincident with chorion formation.The effects of JH I and JH III on both vitellogenin synthesis and ovarain DNA synthesis are statistically similar.     

The juvenile hormone-carrier in the haemolymph of the acridine grasshopperGomphocerus rufus L.: Blocking of the juvenile hormone's action by means of repeated injections of an antibody to the carrier

Summary Egg-production, spermathecal enzyme activity and sexual behaviour inGomphocerus rufus females are shown to be controlled by the corpora allata, i.e. the juvenile hormone (JH). The haemolymph of this insect contains a high molecular weight glyco-lipo-protein (220,000; IEP 6.8) which has a high affinity for JH (Kd=5×10^–8M). This protein binds JH selectively, even in competition with other haemolymph lipoproteins. Purification of the JH-binding protein and subsequent immunisation of rabbits yielded a homogenous antibody solution (Anti-JCv) which eliminated the JH-transport in the haemolymph if it was injected into adult males or females for several days after ecdysis. After this treatment the females did not produce eggs, and spermatophore-formation occurred only partially in the males, this indicating that the Anti-JCv-injections had exactly the same effect as bilateral allatectomy. The haemolymph of related grasshoppers was shown to contain a protein which is immunologically identical to the JH-carrier from theG. rufus haemolymph. It is suggested that the JH produced by the c. allata needs a protein carrier in order to exert its control on the functioning of the reproductive system. The synthesis of the JH-carrier is not dependent upon the presence of JH, i.e. the c. allata, since it is also produced by bilaterally allatectomized males and females throughout their whole life.     

Mobilization of lipid and carbohydrate reserves in the migratory grasshopper Melanoplus sanguinipes

Abstract. The North American migratory grasshopper Melanoplus sanguinipes Fabricius (Orthoptera: Acrididae) exhibits heritable variation in predisposition to make long-duration flights, and performance of long-duration flight enhances reproductive output. As a first step in understanding the physiological basis of these phenomena, we examined the mobilization of lipid and carbohydrate reserves during flight and in response to injection of extracts of the corpora cardiaca. Extract of conspecific corpora cardiaca elevates the concentration of haemolymph lipid. Both synthetic locust adipokinetic hormone I (AKH I) and synthetic Locusta migratoria AKH II raise the concentration of lipid in the haemolymph. However, although AKH I is more active than AKH II in locusts, dose-response curves for the two peptides are similar in M.sanguinipes. Neither extract of conspecific corpora cardiaca nor locust AKH I affects haemolymph carbohydrate in this species. Haemolymph carbohydrate and total glycogen reserves are Diminished by tethered flight; in contrast, haemolymph lipid is elevated by flight. Grasshoppers identified as presumptive migrants or non-migrants do not differ significantly in body composition. Total lipid reserves did not decrease measurably after extended flight, even though total reserves of carbohydrate do not appear to be sufficient to maintain the durations of flight performed.     

Côntrole neuroendocrine des protéines sanguines vitellogenes d'Anacridium aegyptium sain et parasite

The changing patterns of haemolymph proteins were followed in male and female adults of normal and parasitized Anacridium aegyptium during diapause (autumn, winter) or during activity (spring) of their endocrine system without or with electrostimulations of the pars intercerebralis (PI).The haemolymph protein concentration is high in winter and decreases in spring. It is comparatively depleted in locusts infected by the fly Metacemyia calloti. However, the depletion is significant only in ‘castrated’ females.Fifteen protein fractions were resolved by polyacrylamide disk gel electrophoresis in haemolymph of normal and infected locusts during diapause and activity. Some fractions decrease in quantity during activity in males, normal females, and parasitized females with complete ovarian development. One fraction disappears in females with mature eggs and seems correlated with formation of the eggshell. Eight others protein fractions exhibit electrophoretic mobility identical to the 7 protein fractions of homogenates of eggs. There is little doubt that these haemolymph protein fractions are involved in yolk synthesis and are thus ‘vitellogenic’. One of these ‘vitellogenic’ fractions (band 6) is larger in yolk than in blood.Five protein fractions were demonstrated by electrophoresis of homogenates of parasites. Their electrophoretic mobilities are similar to those of 5 of the 8 haemolymph ‘vitellogenic’ fractions of the host. There is little doubt that these 5 haemolymph protein fractions (one of them is the band 6) are involved in the nutritional requirements of the parasite.Electrostimulation of the PI, during diapause and activity, increase the haemolymph protein concentration and chiefly the protein concentration of the blood band 6. Thus, the median neurosecretory cells of the brain (M-NSC) regulate protein synthesis and chiefly the synthesis of ‘vitellogenic’ proteins.In parasitized females, the increase of the haemolymph protein concentration after electrostimulations of the PI is associated with an enhancement of ovarian development. The depletion of the haemolymph protein concentration in ‘castrated’ females is thus involved in the inability of the oöcytes to sequester available proteins from the haemolymph. The haemolymph protein deficiency may be attributed to (1) an impairment of protein synthesis, attendant upon the hypoactivity of the M-NSC, and (2) the nutritional requirements of the parasite.     

Developmental and diel changes of adipokinetic hormone in CNS and haemolymph of the flightless wing-polymorphic bug,Pyrrhocoris apterus (L.)

We have used an enzyme-linked immunoassay (ELISA) for determination of the AKH content in CNS (brain + corpora cardiaca + corpora allata) and haemolymph of adult macropterous and brachypterous females of the bug Pyrrhocoris apterus. The tests revealed that the AKH content fluctuates between 1 and almost 4 pmol/CNS during the first 14 days of adult life and significantly increased in order diapausing brachypters相似文献   

Quantitative determination of the juvenile hormones in the haemolymph of Locusta migratoria during normal development and after implantation of corpora allata

Simultaneous quantitative determination of the three naturally occurring juvenile hormones in insects (JH-I, JH-II and JH-III) was performed on haemolymph samples of both normally developing locusts and locusts implanted with active corpora allata, using capillary gas chromatography with electron capture detection.In fourth instar female larvae, 24–48 hr after the third ecdysis, as well as in adult females, 18 days after the imaginal ecdysis, only JH-III was detected. In fifth instar female larvae JH-III was present in very low concentrations, if at all.After implantation of four pairs of corpora allata taken from young fourth instar female larvae or one pair or corpora allata taken from adult females into fifth instar female larvae 0–24 hr after ecdysis, an elevation of the JH-III titre was observed. Neither JH-I nor JH-II could be detected. The amount of JH-III, already elevated 2 hr after implantation, remained high for several days in comparison to that of control insects. On the third day after the subsequent moult the JH-III level was comparable to that of normally developing fifth instar larvae. Factors involved in the achievement of the haemolymph JH-titre are discussed.     

Hormonal control of lipid synthesis in the fat body of the adult female tsetse fly, Glossina morsitans

Aqueous extracts of brain, thoracic ganglion or corpora cardiaca of female Glossina morsitans were shown to contain a substance which inhibited the synthesis of lipid from l[U-¹⁴C] leucine by fat cells incubated in vitro. The highest concentration of this substance was found in the corpora cardiaca; approximately 1 × 10^?6 gland pairs μl^?1 were required for maximum inhibition. At concentrations greater than 1 × 10^?4 gland pairs μl^?1 the lipid synthesis inhibiting factor (hereafter referred to as the LSIF) was inactivated by the presence of a substance which could be removed by gel filtration. The concentration of LSIF in the corpora cardiaca and midbrain varied throughout the reproductive cycle of the female. Net release of LSIF from the midbrain occurred between the 2nd and 7th day of the 9-day reproductive cycle. Net release from the corpora cardiaca began on day 5 and continued until the end of the interlarval period on day 9. Results are consistent with the hypothesis that LSIF is synthesised mainly in the medial neurosecretory cells of the midbrain whereas the corpora cardiaca are the site of storage and release into the haemolymph. LSIF was present in midbrain and corpora cardiaca extracts from male G. morsitans but at lower concentrations than in females. No variation in LSIF concentration could be correlated with the feeding cycle. LSIF activity was not detected in fresh haemolymph but was found at high concentration in boiled haemolymph, suggesting the presence of an inhibitor which was inactivated at high temperature. Preliminary investigations into the nature of LSIF have shown it to be inactivated by proteolytic enzymes and to be recoverable in a single peak from a Sephadex G15 column.Results support the view that LSIF is a peptide hormone which, in conjunction with an inhibitor, controls the lipid synthetic ability of the fat cells of the adult female tsetse fly throughout the reproductive cycle.     

Biosynthesis and titre of juvenile hormone during the first gonotrophic cycle in isolated and crowded Locusta migratoria females

Basal oöcyte length, corpus allatum volume and “in vitro” juvenile hormone biosynthesis were measured in isolated and crowded Locusta migratoria females at selected times during the first gonotrophic cycle. Using gas chromatography-mass spectrometry with selected ion monitoring, the juvenile hormone titre in the haemolymph of isolated and crowded females was also determined 1 and 4 days after fledging. The rate of oöcyte growth was more rapid in isolated females and a significant (P < 0.01) difference in mean length was apparent as early as 3 days after fledging. This early manifestation of a difference in rate of oöcyte growth was correlated with a difference in haemolymph juvenile hormone titre between isolated and crowded females. Whilst there was no difference in titre 1 day after fledging, by day 4 the juvenile hormone titre in isolated females was found to be approximately twice that in crowded females. There was no significant difference in the rates of juvenile hormone biosynthesis by corpora allata from isolated and crowded females on days 0 through to 6 after fledging. On day 8, however, the rates of juvenile hormone biosynthesis of corpora allata from isolated females were very high (mean value = 136 pmol/h/pair) and were significantly (P < 0.002) greater than those of corpora allata from crowded females. Day 8 was also the point in the first gonotrophic cycle at which the difference in the mean basal oöcyte length in isolated and crowded females was at a maximum. The mean volume of corpora allata from isolated females was greater than that of corpora allata from crowded females at all points at which measurements were taken during the first gonotrophic cycle.     

Étude préliminaire des variations circadiennes des protéines de l'hémolymphe de Penaeus japonicus Bate

The protein contents of the haemolymph in the decapod crustacean Penaeus japonicus Bate exhibit a tricircadian rhythm characterized by two maxima during the night and another one during the day. During the night the total protein concentration in haemolymph is higher in males. Maximal values in males are approximately four times greater (100 mg/ml) than minimal ones (25 mg/ml). Variations are less in females: maximal values are approximately two and a half times higher (75 mg/ml) than minimal ones (30 mg/ml).Electrophoresis in polyacrylamide gradient showed that the different protein constituents in general exhibit similar circadian variations. Time of acrophases depends on the sex and the stage in the intermoult cycle. On the other hand, the mean concentration of each protein constituent calculated from values measured at different times of the day are similar whatever the sex and moulting stage. Between 0 and 6 h certain protein fractions - two in females and one in males - are no longer detectable by electrophoresis. At 12 h, concentration of haemocyanin and its subunits increase simultaneously in both sexes.     

Re-evaluation of the role of corpora cardiaca in calling and oviposition behaviour of giant silk moths

Re-investigation of the role of the corpora cardiaca in the reproductive behaviour of the giant silkmoths, Hyalophora cecropia and Antheraea polyphemus, showed that this pair of glands plays no essential role, either in “calling” behaviour by virgin females or in increased oviposition due to mating. Removal of corpora cardiaca-corpora allata complexes, either from diapausing pupae or from freshly eclosed adult females, had no effect on the calling behaviour or on its timing in either species. Moreover after mating, these operated females laid eggs in the typical mated oviposition pattern. Furthermore, females in which there was only a nervous connection between the brain and the abdomen but no haemolymph circulation called normally and oviposited after mating.Although the corpora cardiaca were not essential for calling behaviour, hormogenates of corpora cardiaca-corpora allata complexes and blood from calling or ovipositing females induced a typical “calling” response in 30–60% of the isolated virgin H. cecropia abdomens tested. This activity was not species-specific as it was also found in Manduca sexta, but the restriction of major activity to corpora cardiaca extracts and haemolymph suggested that a neurosecretory factor may modulate the normal neural control of calling behaviour.     

Effects of metabolic neuropeptides from insect corpora cardiaca on proline metabolism of the African fruit beetle,Pachnoda sinuata

The effect of neuropeptides from the corpora cardiaca of the fruit beetle Pachnoda sinuata on proline metabolism has been investigated in vivo. Conspecific injections of a crude extract from corpora cardiaca cause an increase of the concentration of proline in the haemolymph by nearly 20% and a decrease of the concentration of alanine, the precursor in proline synthesis, by about 64% when compared with a water-injected group. Purification of an extract of corpora cardiaca on reversed-phase liquid chromatography revealed two distinct UV absorbance and fluorescence peaks that cause hyperprolinaemia in the fruit beetle. The major peak is the previously identified octapeptide Mem-CC; the second peak is also a peptide, but its primary sequence remains, as yet, unidentified. Synthetic Mem-CC elicited time- and dose-dependent increases/decreases of the concentrations of proline and alanine in the haemolymph respectively. Furthermore, the receptor for this peptide seems to be specific in P. sinuata: only peptides of the large family of adipokinetic hormones with an Asp, Asn or Gly residue at position 7 could elicit biological activity, whereas those with a Trp, Ser or Val residue at this position did not have any activity.     

Humoral inhibition of the corpora allata in larvae of Diploptera punctata: Role of the brain and ecdysteroids

Juvenile hormone synthesis by adult female corpora allata was inhibited following implantation into final-larval-instar males; inhibition was prevented by decapitation of the larval hosts on day 11 (prior to the head critical period for moulting), but not by decapitation on day 13. Implantation of one larval protocerebrum restored inhibition of implanted corpora allata, demonstrating that the brain releases an inhibitory factor. Corpora allata implanted into larvae decapitated on day 11 were inhibited by injections of 20-hydroxyecdysone. Since treatment of corpora allata with 20-hydroxyecdysone in vitro did not inhibit juvenile hormone synthesis, ecdysteroids probably act indirectly on the corpora allata. Juvenile hormone synthesis and haemolymph ecdysteroid concentration were measured following implantation of corpora allata along with two larval brains into larval hosts. Brain implantation did not affect ecdysteroid concentration, but did inhibit juvenile hormone synthesis, even in animals with low haemolymph ecdysteroid concentration. Incubation with farnesoic acid stimulated juvenile hormone synthesis by corpora allata from males early in the final larval stadium, but not after day 8, showing that one of the final two reactions of juvenile hormone synthesis is rate-limiting in larval corpora allata at this stage. Adult female corpora allata which had been humorally inhibited by implantation into larvae were stimulated by farnesoic acid.