Effect of salinity on the osmotic,chloride, total protein and calcium concentrations in the hemolymph of the prawn Peneaus monodon (fabricius)

• 1.1. Osmolality and chloride concentrations in the hemolymph of Penaeus monodon became stable 1 day after molting in 32 ppt, while total protein and calcium concentrations remained stable throughout the molting cycle. When intermolt (≥ 36 hr postmolt) animals were transferred from control (32 ppt) to experimental (8–40 ppt) salinities, osmolality, chloride and total protein, but not calcium, concentrations in the hemolymph achieved steady state values 24–48 hr after transfer.
• 2.2. The hemolymph osmolality was a linear function (slope = 0.28) of medium osmolality at salinities between 8 and 40 ppt. It was isosmotic to seawater at 698 mOsm (10 g prawns) and 752 mOsm (30 g), and was hyperosmotic to the medium below isosmotic concentrations, and hypoosmotic to those above.
• 3.3. Hemolymph chloride concentration was isoionic to seawater at 334 mM, and was hyperregulated below isoionic concentrations, and hyporegulated to those above.
• 4.4. P. monodon maintained its hemolymph calcium concentration between 6.4 and 10 mM when medium salinities increased from 8 to 40 ppt.
• 5.5. Total protein concentration in the hemolymph was independent of medium salinity (8–40 ppt) and hemolymph osmolality (540–850 mOsm).

     

Growth and hemolymph trehalose levels of Heliothis zea larvae fed diets containing various sugars

• 1.1. The amount of sugar required for growth of Heliothis zea larvae on a chemically defined diet was determined.
• 2.2. Larvae grew well on fructose, galactose, sucrose, trehalose and raffinose diets but not on diets containing more than 0.5% glucose.
• 3.3. A starch diet did not promote rapid larval growth.
• 4.4. Hemolymph trehalose levels in 12-day-old larvae ranged from none to 45μmoles/ml.
• 5.5. A method for analysis of hemolymph trehalose by gas chromatography is described.

     

Effects of l-canavanine on arginine catabolism in manduca sexta (sphingidae: lepidoptera)

• 1.1. Hemolymph ornithine concentrations in tobacco horn worm larvae fed a 2.5 mM l-canavanine plus 25 mM l-arginine-supplemented artificial diet (CAAM) were higher than those in larvae fed diets supplemented with 2.5 mM canavanine (CAV), 25 mM arginine (ARG), or controls (CON).
• 2.2. Ornithine concentrations in CAV-treated larvae were significantly greater than the control or ARG treatment, but less than the CAAM treatment during the latter part of the wandering larval stage and during the pharate pupal stage.
• 3.3. Urea concentrations were greater during the active feeding stage with the CAAM- and ARG-treated larvae having significantly higher levels than control or CAV-treated larvae.
• 4.4. Urea concentrations in all treatments never exceeded 36.5% of the ornithine concentration.
• 5.5. Canavanine concentrations were higher in CAV-treated larvae than in CAAM-treated larvae.
• 6.6. During active feeding, arginine concentrations for all treatments were similar, but were lower in CAV- and CAAM-treated larvae during the pharate pupal stage.

     

Salt-dependent effects of juvenile hormone and related compounds in larvae of the brine shrimp,Artemia

• 1.1. Molting in state III larvae of the brine shrimp. Anemia, is interrupted, or even accelerated, when populations are exposed to various concentrations of juvenile hormone, methyl farnesoate, or methoprene in artificial sea-water.
• 2.2. The effects are believed to be salt-dependent, because exposure to these compounds in sea-water that is isotonic to larval hemolymph had no effect. This suggests that the juvenoids may target the ion transporting epithelia.

     

Effect of low rearing temperature on development of Galleria mellonella larvae and their sensitivity to juvenilizing treatment

• 1.1. The development of Gallena mellonella is strongly affected by a low temperature of 18°C (the last instar persists for more than one year, instead of about 9 days at 30°C). At 18°C the last instar Galleria mellonella larvae respond to juvenilizing treatment—chilling stress or juvenile hormone analogue—with a very low percentage or no supernumerary moults, respectively.
• 2.3. Experiments in which larvae subjected to such treatments were transferred from 18°C to 30°C and vice versa showed that for the realization of the larval programme after chilling stress application the higher (30°C) temperature is needed.
• 3.4. In last instar larvae reared at 18°C there coexist very high juvenile hormone titre and high juvenile hormone esterase activity.
• 4.5. This phenomenon which is found in both, chilled and unchilled larvae, is discussed.

     

Amino acid activating enzymes in Sarcophaga bullata

• 1.1. The fat-body soluble fraction from two-day Sarcophaga bullata larvae contain amino acid activating enzymes for nineteen amino acids.
• 2.2. The level of activity varies with the amino acid substrate.
• 3.3. The total ³²PP-ATP exchange activity of the pupae decreased with age for the first 6 days, then increased to a maximum one or two days prior to emergence of the adults.
• 4.4. The free amino acid concentration in the pupae decreased during the period when the amino acid activating activity increased.

     

Effect of developmental derangements on the proteolytic and protease-inhibitory activities in Galleria mellonella (Insecta)

• 1.1. Protease inhibitory activity in the whole body homogenates of Galleria mellonella larvae exhibits maxima at the beginning of the last larval and pupal instars. Injury, chilling, immobilization, and ligations of larvae cause an increase of inhibition.
• 2.2. The inhibitory activity is high in the haemolymph but low in midgut and faty body. By contrast, the proteolytic activity is low in haemolymph and high in both midgut and fat body.
• 3.3. Starvation and ligations cause a dramatic fall of the proteolytic activity and increase of the inhibitory activity in examined organs.

     

Effects of water stress on hemolymph volume,osmotic potential and chemical composition in Megetra cancellata

• 1.1. Rates of water loss in Megetra cancellata were very high compared to those reported for other xeric arthropods.
• 2.2. Hemolymph weight in hydrated animals was 43.0% of the total body weight while it was 24.7% in desiccated animals that had lost 16.1% of their body weight as water.
• 3.3. Hemolymph osmotic potential increased from 417 to 447 mOsm/kg in desiccated beetles, but osmotic regulation was evident.
• 4.4. Total hemolymph protein mass and concentration decreased in desiccated beetles while amino acid concentrations remained constant (at about 70 mM).
• 5.5. Na⁺ and −PO₄ concentrations increased in desiccated beetles.
• 6.6. Cl⁻ and K⁺ concentrations in desiccated beetles were equal to those in undesiccated beetles.

     

Induction of locomotor behavior in the giant African snail,Achatina fulica

• 1.1. The locomotor-inducting factor of the giant African snail, Achatina fulica, was examined.
• 2.2. Snails showed nocturnal circadian behavior in relative humidity at least over 50%. Although the rhythmicity was independent of light and darkness, it was disturbed easily by hydration, and hydrated snails continued to locomote throughout the day. For induction of locomotor behavior, relative humidity over 50% was the fundamental factor and water is shown to be the limiting factor for the endogeneous circadian oscillator.
• 3.3. The integument of snails showed a higher water permeability. Through the integument, hemolymph osmolality changed easily according to hydration and dehydration from about 120 to 400 mOsm/kg H₂O. Circadian behavior was induced in snails in which hemolymph osmolality ranged from about 130 to 230 mOsm/kg H₂O.
• 4.4. By hydration, hemolymph osmolality in quiescent and estivated snails which have higher osmolality decreased gradually and then they began to locomote according to the degree of dilution, and vice versa. The induction of behavior in these snails was controlled by low hemolymph osmolality.
• 5.5. Together with the endogeneous rhythmicity, water environment was shown to be the key factor for the induction of locomotor behavior.
• 6.6. Based on these results, the mechanisms of the induction of locomotor behavior in terrestrial pulmonates are proposed.

     

Comparative dehydrogenase activity during the ontogenesis of the yellow fever mosquito Aedes (Stegomyia) aegypti L. (diptera:culicidae)

• 1.1. α-GPDH in most active in adults, LDH in third instar larvae, and MDH in third instar larvac.
• 2.2. During pre-pupal growth, LDH is the most active enzyme, followed by MDH and α-GPDH; while during post-pupal growth, MDH is most active followed by α-GPDH and LDH.
• 3.3. Increased enzyme activity is in response to changing physiological and physical environments, and is due to temporal activation of new gene loci indicated by the production of new α-GPDH and MDH isozymes. LDH activity is probably controlled by the temporal action of regulatory gene(s).
• 4.4. Dehydrogenase activity profiles during ontogenesis are probably species-specific.

     

Juvenile hormone biosynthesis by corpus cardiacum-corpus allatum complexes of larval Lymantria dispar

• 1.1. A radiochemical assay was used to examine juvenile hormone (JH) synthesis and secretion in vitro by incubating two pairs of larval corpus cardiacum-corpus allatum complexes (CC-CA) from, Lymantria dispar, in 50 μl of osmotically balanced Grace's medium containing 1 μC1 [³H-methyl]-methionine for 6 hr.
• 2.2. For CC-CA of fourth instar female larvae, maximal incorporation of ³H-methyl was 0.15 pmol/pr/hr between days 2 and 3. High pressure liquid chromatographic (HPLC) analysis suggested that the biosynthetic products are mainly JH III with a little JH II at times.
• 3.3. For CC-CA of last instar female larvae, incorporation of ³H-methyl was 0.48 pmol/pr/hr at the beginning of the stadium and decreased to negligible levels by day 10. HPLC analysis suggested that CC-CA of last instar larvae produced only JH III. Volume increases in CA during the last instar were associated with declining activities of JH secretion.
• 4.4. Comparisons of maximal rates of ³ H-methyl incorporation by each unit volume of CA revealed that in the last instar each unit volume (μm³) of glandular tissue secreted 50% more JH than in the fourth instar.

     

The effects of osmotic stressors on the stenohaline carp (Cyprinus carpio)

• 1.1. Carp were acclimatized to different concentration of urea and mannitol.
• 2.2. The fish survived in 300 mOsm urea and 262 mOsm mannitol for a longer period. Higher concentrations were only tolerated for a short time.
• 3.3. Urea penetrated into the animals. The internal concentration of urea in plasma was nearly equal to the outside concentration after 7 days. Therefore a very high internal osmolality was adjusted (sum of normal and urea osmolality).
• 4.4. Urea treatment only resulted in changes of Ca level, while the concentration of other electrolytes was not clearly varied.
• 5.5. Extracellular space of muscle was reduced while the intracellular space remained unchanged after urea treatment.
• 6.6. Mannitol treatment resulted in changes of electrolyte concentrations due to dehydration.
• 7.7. After 1 day of treatment the concentration of Na in plasma decreased which might indicate the limitation of tolerance.
• 8.8. Immediate shrinkage of ICS and, later, reduction of ECS were clear reactions to mannitol influence.

     

Spermiogenesis of the testes of juvenile hormone-treated silkworm larvae,Bombyx mori

• 1.1. To examine changes in the percentages of testicular cells such as 1C cells (spermatids and spermatozoa), 2C cells (G1 somatic cells, spermatogonia and secondary spermatocytes), 2–4C cells (somatic and germinal cells in S phase) and 4C cells (G2 somatic cells and primary spermatocytes), we isolated nuclei from the testes of silkworm larvae and subjected them to flow cytometric analysis.
• 2.2. In control testes, 1C cells appeared at day 0 of the fifth instar, increased gradually by spinning and increased steeply at 2 days later still spinning. The percentage of 2C cells decreased gradually after ecdysis to the fifth instar. The percentage of 4C cells increased from day 2 to day 5 of the fifth instar and decreased after day 11 of this instar. Cells in S phase remained constant through the fifth instar.
• 3.3. An injection of juvenile hormone analog, methoprene, at day 0 of the fifth instar did not inhibit spermiogenesis, but resulted in increased 2C cells and decreased 4C cells dose-dependently. In contrast, the same treatment at day 2 of the fifth instar did not change the percentages of 1C, 2C and 4C cells of the testes at all, suggesting that the testes changed sensitivity to the hormone at larval development.
• 4.4. Repeated injections of methoprene to induce the appearance of dauer larvae resulted in a complete block of the development of 1C cells.

     

Evaluation on the hydrolysis of methylumbelliferyl-tetra-N-acetylchitotetraoside by various glucosidases. A comparative study

• 1.1. In human plasma, an enzyme is present which hydrolyzes 4-methylumbelliferyl-tetra-N-acetylchitotetraoside. The function of this enzyme is unknown.
• 2.2. We have examined whether hyaluronidase, neutral endoglucosaminidase, $\text{N-}\text{acetyl}\text{-β-}\text{d}\text{-}\text{hexosaminidase}$, aspartylglucosaminidase, β-d-glucosidase, and chitobiase could hydrolyze MU-TACT. The results obtained are detailed below.
• 3.3. A purified commercial preparation of hyaluronidase does not hydrolyze MU-TACT.
• 4.4. Substrate specificity requirements, pH optimum and subcellular localization indicate that neutral endoglucosaminidase is distinguishable from MU-TACT hydrolase. Also commercial neutral endoglucosaminidase D and H have no affinity towards MU-TACT.
• 5.5. $\text{N-}\text{Acetyl}\text{-β-}\text{d}\text{-}\text{hexosaminidase}$ is different from MU-TACT hydrolase for the following reasons: (a) a purified enzyme preparation does not hydrolyze MU-TACT; (b) there is no correlation in the activity of the enzymes; (c) MU-TACT hydrolase is not deficient in cells of a patient with a deficiency of total $\text{N-}\text{acetyl}\text{-β-}\text{d}\text{-}\text{glucosaminidase}$; and (d) the 2 enzymes have very different Chromatographic characteristics and Con A binding properties.
• 6.6. Enzyme characteristics, substrate structural requirements and a lack of correlation with MU-TACT hydrolase activity suggest that aspartylglucosaminidase, β-d-glucosidase, and chitobiase are not involved in the hydrolysis of MU-TACT.
• 7.7. None of the enzymes which we have considered corresponds to MU-TACT hydrolase. The exact nature and the function of the enzyme remains an enigma.

     

Effects of dietary T-2 toxin concentrations fed to larvae of the yellow mealworm at three dietary protein levels

• 1.1. Growth, but not survival, of larvae of Tenebrio molitor was influenced by concentration of dietary protein, by concentration of T-2 toxin and by interaction of the two.
• 2.2. T-2 toxin reduced the quantities of food and protein used by the larvae and, consequently, gain in larval weight.
• 3.3. Efficiency of food conversion was constant, but efficiency of protein conversion was influenced by dietary protein and dietary mycotoxin concentration.
• 4.4. Concentrations of T-2 toxin of 64 and 128 ppm depressed growth of test larvae significantly, but these levels exceeded the biologically active levels in vertebrates.
• 5.5. A new technique for determining food utilization by insect larvae is described.

     

Purification and characterization of a novel chymotrypsin inhibitor controlled by the chymotrypsin inhibitor A (Ict-A) gene from the larval hemolymph of the silkworm,Bombyx mori

• 1.1. On polyacrylamide gel electrophoresis, chymotrypsin inhibitors in the larval hemolymph of the silkworm were found as 15 electrophoretically distinct bands.
• 2.2. One of them, CI-13 migrating fastest toward the anode, was purified from the hemolymph.
• 3.3. The inhibitor was a monomeric protein with a molecular mass of 14,000 and showed stability for both heat and a wide range of pH. The isoelectric point was pH 4.1.
• 4.4. CI-13 was able to inhibit chymotrypsin completely and trypsin slightly, but was ineffective against other proteinases such as papain, ficin, carboxypeptidase A, V8 proteinase, serratia peptidase, cocoonase and proteinases derived from gut juice of the silkworm.