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Correlation between concentration of hemolymph nutrients and amount of fat body consumed in lightly and heavily parasitized hosts (Pseudaletia separata).

Two states of parasitization in the Pseudaletia separata-Cotesia kariyai system were examined: one that was lightly parasitized and one that was heavily parasitized. We predicted that the consumption of fat body and hemolymph nutrients depends on the number of parasitoid larvae in the host. Lightly parasitized hosts (average clutch size+/-S.E.: 42.5+/-16.2, N=15) and heavily parasitized hosts (average clutch size+/-S.E.: 230.2+/-8.8, N=15) were prepared artificially. Eight days after parasitization, perivisceral fat body was depleted in the heavily parasitized host, although peripheral fat body was not yet consumed, but by day 10 most of the peripheral fat body was consumed. In lightly parasitized hosts, perivisceral fat body was not consumed by day 10. The parasitoid larvae deplete the perivisceral fat body first and then consume the peripheral fat body in the heavily parasitized host. The amount of trehalose, the major carbohydrate in the hemolymph, was related to the number of parasitoid larvae developing in the host. In a heavily parasitized host, trehalose concentrations remained low. However, in lightly parasitized hosts, the amount of trehalose increased 8 days after parasitization and then decreased by day 10. Protein and total lipid concentrations in the hemolymph of the heavily parasitized host were significantly lower than in lightly parasitized host on day 10, suggesting that the large number of parasitoid larvae depleted the fat body and hemolymph nutrients by day 10. High concentrations of total lipid on day 8 and 10 in lightly parasitized hosts and on day 8 in heavily parasitized host are likely to be attributed to the teratocytes.

Adipose Tissue↗

A morph-specific daily cycle in the rate of JH biosynthesis underlies a morph-specific daily cycle in the hemolymph JH titer in a wing-polymorphic cricket.

A previous study documented a high amplitude, morph-specific daily cycle in the hemolymph JH titer in the wing-polymorphic cricket, Gryllus firmus. The JH titer rose and fell 10-20 fold in the flight-capable [LW(f), long-winged] morph during the late-photophase-early scotophase, while it was relatively constant during that time in the flightless (SW, short-winged) morph. In the present study we documented a dramatic morph-specific daily cycle in the in vitro rate of juvenile hormone (JH) biosynthesis that was tightly correlated with the hemolymph JH titer on days 5-7 of adulthood. Biosynthetic rates rose and fell 1-2 fold between the late photophase-early scotophase on each of days 5-6 and 6-7 of adulthood in the LW(f) morph, while biosynthetic rates were relatively constant during this period in the flightless, short-winged morph (SW), except for a slight dip in the rate of biosynthesis late in the photophase on these days. Similar morph-specific patterns of JH biosynthesis were observed whether rates were measured on corpora allata attached to corpora cardiaca in males or females, or on corpora allata alone. Hemolymph juvenile hormone esterase activity was significantly higher in the LW(f) vs. the SW morph during the beginning of scotophase, when the JH titer is decreasing rapidly in the LW(f) morph. Results indicate that the morph-specific daily cycle in the JH titer in G. firmus is primarily regulated by a morph-specific daily cycle in the rate of JH biosynthesis and to a lesser degree by hemolymph JH esterase activity. This is the first documentation of a diurnal cycle in the rate of JH biosynthesis in any insect, or a daily cycle in the rate of JH biosynthesis that is correlated with a specific morph in a polymorphic species. Results have important implications for the endocrine regulation of dispersal polymorphism, circadian rhythms of insect hormone titers and their regulators, and general studies of the JH titer and its regulation in insects.

Animals↗

Relationship between firing activity of bombyxin-producing neurosecretory cells and hemolymph bombyxin titer in the silkworm Bombyx mori.

Isolated brain-retrocerebral neurohemal complex of the silkworm of Bombyx mori was stimulated electrically and the released bombyxin (an insulin-like neuropeptide) was measured using time-resolved fluoroimmunoassay. The amount of bombyxin release depended on the number of stimulus pulses delivered to the axonal tract of the bombyxin-producing (BP) neurosecretory cells, and 17 fg of bombyxin per pulse was released from a cell. The titer of bombyxin in the hemolymph of bombyxin-II injected pupae decreased exponentially, the half-life being 170 min. To relate firing activity of a population of BP cells to the hormone titer in the hemolymph, bombyxin titer and its change in the hemolymph were calculated numerically. We assumed that the amount of bombyxin release was proportional to the firing rate of BP cells and the released bombyxin was inactivated with the same time course of injected bombyxin. Our calculations suggested that the hemolymph bombyxin titer may fluctuate dynamically and the mean titer is 380 pg/ml, a level which is close to the actually determined bombyxin titer at middle stages of pupal-adult development.

Animals↗

Silkworm hemolymph as a potent inhibitor of apoptosis in Sf9 cells.

We have previously shown that silkworm hemolymph exhibits anti-apoptotic activity against baculovirus-induced Sf9 cell apoptosis. In this study, using various chemical inducers, such as actinomycin D, camptothecin, and staurosporine, we found that silkworm hemolymph inhibits insect cell apoptosis induced not only by baculovirus but also by chemical inducers. This indicates that silkworm hemolymph contains anti-apoptotic components that work directly in insect cell apoptosis without any booster expression of baculoviral genes. With the analysis of Sf-caspase-1 activity, it was found that the inhibitory effect of silkworm hemolymph works in a further upstream step than the Sf-caspase-1 activation step.

Animals↗

Cation concentrations in the hemolymph of Loligo pealei.

Hemolymph and protein-free hemolymph obtained from Loligo pealei were analyzed for cation concentration by the method of atomic absorption spectroscopy, for the following ions: Na+, K+, Ca++, and Mg++. No significant differences were seen in ion concentration between hemolymph and protein-free hemolymph. Of particular neurophysiological significance is that K+ ion concentration is much closer to that of seawater than previously reported.

Animals↗

The role of hemolymph proline as a nitrogen sink during blood meal digestion by the mosquito Aedes aegypti.

Mosquitoes utilize the amino acids derived from blood meal protein to produce egg proteins. But the amino acids can also be used to produce egg lipid or can be oxidized for energy production. These latter two processes result in the release of nitrogen as toxic ammonia. Therefore, amino acids must be processed in such a way that amino acid nitrogen can be incorporated into non-toxic waste products. Proline is the predominant amino acid in the hemolymph of the adult female mosquito Aedes aegypti. After feeding on albumin meal, hemolymph proline levels increased five-fold over unfed levels, reached maximal levels in the first hours after feeding and remained high through oviposition. Hemolymph proline levels increased as the concentration of protein in the meal increased. When starved of sugar for 24 h prior to feeding on an albumin meal, hemolymph proline levels increased four-fold over the proline levels of non-starved mosquitoes. Proline levels after feeding on a protein deficient in essential amino acids, pike parvalbumin, increased to twice the levels of albumin fed mosquitoes. Based on these observations, we propose that mosquitoes utilize proline as a temporary nitrogen sink to store ammonia arising from deamination of blood meal amino acid.

Aedes↗

An evaluation of hemolymph cholinesterase activities in the tropical scallop, Euvola (Pecten) ziczac, for the rapid assessment of pesticide exposure.

The use of sequential measurements of hemolymph cholinesterase activities as a non-invasive biomarker of seasonal organophosphate/carbamate exposure was investigated for the tropical scallop, Euvola (Pecten) ziczac. Overall activities of both acetylcholinesterase and butyrylcholinesterase were relatively high compared to studies with bivalve tissues. Acute in vivo experiments showed inhibition of hemolymph acetylcholinesterase activity at concentrations of the organophosphate insecticide chlorpyrifos of 0.1, 1 and 10 ng l(-1). Monthly sampling of hemolymph from scallops at two sites in Bermuda over a 15 month period showed seasonal acetylcholinesterase and butyrylcholinesterase inhibition. Direct and indirect evidence suggests that this inhibition did not relate to biochemical or physiological changes associated with gonad maturation and spawning, but rather reflected diffuse contamination of the marine environment by cholinesterase inhibitors or increased bioavailability of such inhibitors at these times. Repetitive sampling of scallop hemolymph for cholinesterase activities represents a rapid, sensitive and non-invasive method for assessing seasonal, sublethal pesticide exposure in these commercially important bivalves and suggests a wider use in marine pollution monitoring.

Animals↗

Apolipophorin-III in Galleria mellonella potentiates hemolymph lytic activity.

Heat-inactivated serum of non-immune Galleria mellonella larvae enhanced the lytic activity of larval cell-free hemolymph against Micrococcus lysodeikticus. The increase in bacterial lysis was due to a 17.2 kDa protein known previously to bind to bacterial lipopolysaccharides. The protein enhanced the lytic activity of insect cell-free hemolymph and hen lysozyme in vitro and insect hemolymph in vivo. The hydrophobic protein, which adhered to M. lysodeikticus, was identified by its amino acid sequence homology as apolipophorin-III. The titer of apolipophorin-III in 200-250 mg last instar larvae was 8.7 mg/ml of hemolymph. Apolipophorin-III did not bind to lysozyme. A possible mode of action of apolipophorin-III with lysozyme in the insect is proposed.

Amino Acid Sequence↗

Induction of mosquito hemolymph proteins in response to immune challenge and wounding.

The rapid induction of proteins in the hemolymph of the mosquito, Anopheles gambiae, was examined after wounding or injection of immune elicitors (Escherichia coli, lipopolysaccharide, laminarin, zymosan). One-dimensional gel electrophoresis revealed at least six hemolymph polypeptides >25 kDa that consistently appeared after any breech of the cuticle. All of these polypeptides appeared in the hemolymph within 30 min and reached a maximum concentration after approx. 6 h. No proteins were specifically induced by bacteria or bacterial or fungal cell wall products, however two constitutively expressed proteins were repressed by these injections. Patterns of hemolymph proteins were further analyzed by two-dimensional electrophoresis. Seven spots were enhanced or induced 2 h after injection in four replicate experiments. An additional two spots demonstrated some variability between replicates, but were generally responsive to injection. These rapidly induced polypeptides are candidates for regulating and initiating the mosquito's responses to pathogens and wounding.

Animals↗

Purification and properties of a small lipid-binding protein from the hemolymph of Triatoma infestans.

A small lipid-binding protein (sLBP) was purified from the hemolymph of the blood-sucking bug Triatoma infestans. Its isolation involved size exclusion-high performance liquid chromatography (HPLC) followed by anion exchange chromatography-HPLC. The molecular weight of the protein, as determined by gel permeation chromatography, was 20 kDa. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) resolved the protein into a single polypeptide with M(r) approximately equal to 16 kDa. The sLBP contains 6% lipids. Diacylglycerols represent the major lipid class, whereas phosphatidyl-choline, phosphatidyl-ethanolamine, free fatty acids and hydrocarbons were found in minor amounts. The amino acid composition indicated a high content of aspartic and glutamic acids and non-polar aliphatic amino acids. The N-terminal sequence did not resemble the sequence of any other previously reported insect hemolymph protein. Far-UV circular dichroism suggested that sLBP adopts a conformation rich in beta-sheet structure. The presence of this protein in hemolymph, fat body and unfertilized eggs was explored throughout the last nymphal and adult stages of the insect by Western blot assays. These assays indicated that sLBP is particularly abundant in hemolymph. A high concentration of sLBP was also detected in the fat body of the nymphs.

Amino Acids↗

Specific binding of human interferon-gamma to particulates from hemolymph and protocerebrum of tobacco hornworm (Manduca sexta) larvae.

Specific binding sites for human interferon-gamma (hIFN-gamma) were found on particulates prepared from the hemolymph and protocerebrum of fifth-instar larvae of the tobacco hornworm, Manduca sexta. A portion of these sites could be solubilized in an active form by the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS). A well-defined specific binding was also associated with hemolymph particulate residue after solubilization by CHAPS. About one-half of [125I]hIFN-gamma binding could be displaced by heparin. The bound hIFN-gamma could be covalently cross-linked to the binding sites using disuccinylamide suberate, and the molecular weight range of these complexes was 200-800 kDa as determined by density gradient sedimentation and gel-exclusion chromatography. Only a small fraction of the hemolymph IFN-gamma binding could be competed by another mammalian cytokine, rat prolactin (rPRL), while there was no sensitivity to rat growth hormone. The small specific rPRL binding found in Manduca hemolymph showed an affinity similar to the prolactin sites found in the liver of pregnant rats. The detergent-insoluble Manduca hIFN-gamma binding was bimodal and similar in affinity distribution to the binding found with human platelet membranes (Kdiss range 0.1-2 nM). The detergent-solubilized IFN-gamma sites were homogenous, with a Kdiss of about 1.5 nM. The IFN-gamma binding sites in Manduca tissues may therefore include molecular species similar to the known invertebrate cytokine receptors and proteoglycan co-receptors.

Amino Acid Sequence↗

Fat body fructose-2,6-bisphosphate content and phosphorylase activity correlate with changes in hemolymph glucose concentration during fasting and re-feeding in larval Manduca sexta.

Fasting of second-day fifth instar larval Manduca sexta leads to a rapid decrease in hemolymph glucose concentration from 3.39+/-0.29 to 0.33+/-0.06 mM in 1 h, along with a decrease in the fructose-2,6-bisphosphate content in the fat body (from 5.92+/-0.31 to 2.80+/-0.47 nmol fructose-2,6-bisphosphate/g fat body in 3 h) and activation of fat body glycogen phosphorylase (from 16% to 55-65% phosphorylase a). During re-feeding an increase in the glucose level in the hemolymph was observed (from 0.36+/-0.05 to 3.91+/-0.36 mM in 3 h), along with an increase in the fructose-2,6-bisphosphate level in the fat body (from 2.88+/-0.47 to 6.66+/-0.42 nmol fructose-2,6-bisphosphate/g fat body in 3 h) and inactivation of fat body glycogen phosphorylase (from 56% to 16% phosphorylase a). These data are consistent with the hypothesis that a decrease in hemolymph glucose both activates fat body glycogen phosphorylase and causes a decrease in fat body fructose-2,6-bisphosphate content. Both of these changes would favor conversion of stored glucose to trehalose in the fat body. When second-day larvae were decapitated, the changes in hemolymph glucose and fat body fructose-2,6-bisphosphate were very similar to those observed in fasting whole insects. These data are consistent with a direct role for glucose in controlling carbohydrate metabolism in Manduca sexta.

Animals↗

Developmental profile of the changes in the prothoracicotropic hormone titer in hemolymph of the silkworm Bombyx mori: correlation with ecdysteroid secretion.

A very sensitive time-resolved fluoroimmunoassay for the prothoracicotropic hormone (PTTH) of the silkworm Bombyx mori has been established. The lower limit of detection in this assay was 0.1 pg. With this assay method, the amounts of PTTH in the central nervous system and hemolymph were quantified. PTTH was detected only in the brain within the central nervous system, and, in the fifth instar, its content in the brain increased gradually with larval growth and decreased rapidly after the beginning of wandering. A substantial amount of PTTH was also found in the retrocerebral complex of day-3 fifth instar larvae, accounting for 28% of total PTTH. The PTTH titer in hemolymph changed dramatically during Bombyx development, with a small peak in the middle of the fourth instar, medium-sized peaks at the wandering and prepupal stages in the fifth instar, and a large prolonged peak during early pupal-adult development. The changes were overall closely correlated with those in hemolymph ecdysteroid titer. However, some unexpected aspects of PTTH dynamics in hemolymph have also been disclosed. Based on these observations, the significance of PTTH secretion in the control of insect development is discussed.

Animals↗

Insect hemolymph clotting: evidence for interaction between the coagulation system and the prophenoloxidase activating cascade.

Here we describe a novel approach to isolate proteins involved in insect hemolymph coagulation. In order to avoid problems in purifying clot proteins after they had been crosslinked, we performed an in vitro coagulation reaction with cell-free hemolymph from the lepidopteran Galleria mellonella and used the resulting complexes to produce a specific antiserum. The antiserum reacted with a subset of hemolymph proteins as well as with granular cells, but not with other hemocyte types of Galleria. Screening expression libraries identified some positive clones, which turned out to code for some previously characterized components of immune cascades, as well as some novel candidates for clotting factors. Known components include members of both the coagulation system and the prophenol-activating cascade, lending support to the idea that both systems work together during the formation of a hemolymph clot. Novel candidates for insect clotting factors include a mucin-like protein, a glutathione-S-transferase, and a distant member of the alpha-crystallin/small heat shock protein family. Using assays measuring the activity of transglutaminase, a key enzyme in clotting reactions in both vertebrates and invertebrates, we found a partial overlap between transglutaminase substrates and proteins recognized by the antiserum against the in vitro-induced clot.

Amino Acid Sequence↗

Polyunsaturated hydrocarbons in the hemolymph: biosynthetic precursors of epoxy pheromones of geometrid and arctiid moths.

Female moths of many species in Geometridae, Arctiidae and some other macrolepidopteran families produce epoxy pheromones, which are probably derived from polyunsaturated hydrocarbons. In order to understand a biosynthetic site, hemolymph from both sexes of two geometrid species, Ascotis selenaria cretacea and Hemerophila artilineata, and one arctiid species, Spilosoma imparilis, was shaken with n-hexane and the solvent extracts were analyzed by GC-MS. Each extract of the female hemolymph sex-specifically included polyunsaturated hydrocarbons corresponding to the pheromonal epoxy components in addition to many saturated hydrocarbons, but no epoxy compounds were detected in it. Based on this analysis, deuterated polyunsaturated hydrocarbons were injected into the abdomens of two geometrid females, and the labeled epoxy components were successfully yielded from the pheromone glands. This result indicated that the polyunsaturated hydrocarbons occurring in the female hemolymph were direct pheromone precursors, which might be produced outside the pheromone gland, probably in oenocytes associated with abdominal epidermal cells or in the fat body, and transported to the pheromone gland via the hemolymph for their epoxydation and emission into the atmosphere.

Animals↗

Hemolymph levels of methyl farnesoate increase in response to osmotic stress in the green crab, Carcinus maenas.

The salinity of estuarine environments can vary widely, exposing resident organisms to considerable osmotic stress. The green crab Carcinus maenas is well known for its ability to osmoregulate in response to such stress. Therefore, we tested the relationship between osmoregulation and hemolymph levels of methyl farnesoate (MF), a compound previously shown to rise in response to various types of environmental stresses. When crabs were transferred from 100% seawater to dilute (hypo-osmotic) seawater, hemolymph osmolality dropped rapidly, reaching an acclimation level 48 h after transfer. Hemolymph levels of MF also rose in these animals after a delay of 6 h, and reached a maximum level at 48 h. MF levels remained elevated as long as the crabs were maintained in dilute seawater, and quickly returned to basal levels when the animals were returned to full strength seawater. In most (but not all) animals, MF levels were elevated when hemolymph osmolality fell below the isosmotic point (approx. 800 mOsm/kg). These data suggest that MF may have a role in osmoregulation by this species. In addition, the elevation of MF by hypo-osmotic seawater suggests an experimental strategy for manipulating MF levels in crustaceans.

Animals↗

Affinity purification and binding analysis of the hemolymph juvenile hormone binding protein from Manduca sexta.

A high-affinity juvenile hormone binding protein was purified from the hemolymph of the tobacco hornworm, Manduca sexta, employing ammonium sulfate precipitation and affinity and size-separation chromatography. The naturally occurring enantiomer of juvenile hormone III (10R) was converted to juvenile hormone III acid and then covalently attached to aminohexyl-Sepharose 4B. Hemolymph from early fifth stadium (60 h postecdysis) larvae was used as the source of hJHBP. The yield of hJHBP was approximately 25% of the starting material, with 3.5 mg of highly purified, biologically active hJHBP recovered from 100 mL of hemolymph. Binding parameters were examined using equilibrium dialysis and highly purified, enantiomerically correct juvenile hormone I and II and racemic JH III. The equilibrium dissociation constants for juvenile hormone I and II were approximately 6 x 10(-10) M at 4 degrees C, while racemic juvenile hormone III displayed an equilibrium dissociation constant of 1.9 x 10(-9) M. At 25 degrees C the equilibrium dissociation constant for juvenile hormone I was 1.6 x 10(-9) M. Half-times of dissociation were also determined for the three homologs. The half-time of dissociation was 30 s for juvenile hormone I, 20 s for juvenile hormone II, and 13 s for juvenile hormone III at either 4 or 25 degrees C. Using the new equilibrium dissociation constants, we calculate that better than 99% of the circulating juvenile hormone titer may be bound to this hemolymph protein.

Animals↗

Purification and characterization of an anti-apoptotic protein isolated from Lonomia obliqua hemolymph.

Previously it was reported that supplementation of insect cell culture with Lonomia obliqua hemolymph could extend culture longevity (Maranga et al. Biotechnol. Prog. 2003, 19, 58-63). In this work the anti-apoptotic properties of this hemolymph in Spodoptera frugiperda (Sf-9) cell culture were investigated. The presence or absence of apoptotic cells was characterized by light microscopy, flow cytometry, and agarose gel electrophoresis. Hemolymph was fractionated by several ion exchange and gel filtration chromatographic steps for identification of the compounds responsible for this effect. Fractions exhibiting a potent anti-apoptotic effect were isolated and tested in cell culture. A protein of about 51 kDa was identified, isolated, and tested for apoptosis inhibition. Addition of this purified protein to Sf-9 cultures was able to prevent apoptosis induced by nutrient depletion as well as by potent apoptosis chemical inducers such as Actinomycin D. This work confirms that the enhanced culture longevity obtained by supplementation with L. obliqua hemolymph is due to the presence of potent anti-apoptotic factors.

Animals↗