Oxygen uptake in larval bollworms (Heliothis zea) infected with the fungus Nomuraea rileyi

• 1.1. Healthy 6- to 12-day-old Heliothis zea (bollworm) larvae showed a mean oxygen uptake of 3.1 μl O₂/mg body wt per hr.
• 2.2. Similar larvae infected with the fungus Nomuraea rileyi had a mean uptake of 4.01 μl O₂/mg per hr.
• 3.3. The weights of the two groups of insects did not differ.
• 4.4. T-test showed a significant (P < 0.01) difference in oxygen uptake between healthy and infected larvae.

     

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.

     

A starvation test to determine optimal salinities for larval freshwater prawns,Macrobrachium rosenbergii

• 1.1. A starvation test was conducted in small beakers with stage 1 (S1) and stage 2 (S2) Macrobrachium rosenbergii larvae to determine optimal salinities.
• 2.2. Experiments were first performed with S2 larvae at 13 ppt to identify a suitable medium made with artificial sea salts.
• 3.3. A broad-range (0–35 ppt) and a subsequent narrow-range (9–16 ppt) salinity experiment with S2 larvae were used to identify 13 ppt as the optimal salinity, with 12 ppt as the next best; this agrees well with most previous estimates of optimal salinities for rearing larvae.
• 4.4. S1 larvae were also tested in a narrow-range salinity experiment but were not used further because, unlike starved S2 larvae, they molted during the experiment.
• 5.5. Identification of the optimal salinity was not affected by 50% daily water exchange or by bright light.
• 6.6. Exposure of larvae to three different salinities—7, 13 and 19 ppt—during S1 influenced the width of the optimal salinity range for S2 larvae.

     

Cardiac responses of larval and adult tiger salamanders to submergence and emergence

• 1.1. The ECG of aquatic Amhystoma tigrinum from the Colorado Rocky Mountains was recorded while the animals submerged and emerged in water. Older larvae and metamorphosed adults were compared.
• 2.2. Free-swimming animals of both types showed slight emergence tachycardia when taking a “gulp” of air.
• 3.3. Preventing access to air for 30 min or more resulted in a slight bradycardia in larvae. Some adults responded with increased, others with decreased, heart rate depending on their level of excitement.
• 4.4. Restraining the animals before forced submergence caused a greater bradycardia than when unrestrained.
• 5.5. Low dissolved oxygen accentuated the cardiac responses of larvae to submergence but not in adults.
• 6.6. Atropine only partially blocked the diving responses of both forms.
• 7.7. The degree of submergence bradycardia seems to be a function of the ability to extract oxygen from water. It probably is not an adaptation to diving in these forms. Instead the submerged heart rate in these predominantly aquatic salamanders may be the “normal” rate with emergence tachycardias for breaths of air.

     

Histochemical staining of cadmium taken up by the midge larva,Chironomus yoshimatsui (diptera,chironomidae)

• 1.1. The midge larva (Chironomus yoshimatsui) exposed to cadmium (10 μg Cd/ml) for 2 days was histochemically stained with benzothiazolylazo-β-naphthol.
• 2.2. A large portion of cadmium taken up by the larvae was distributed to the digestive tract, epithelial tract and fat bodies.
• 3.3. Cadmium accumulated in the fat bodies was discharged slowly relative to cadmium in the tract contents when the larvae were placed in control water.
• 4.4. Glycogen in the fat bodies of cadmium-exposed larvae was insensitive to PAS staining.

     

Changes in free amino acid composition in haemolymph of larvae of the wax moth,Galleria mellon ella L., during cold acclimation

• 1.1. Free amino acids were analysed in the haemolymph of Galleria mellonella larvae by HPLC chromatography with o-phthaldialdehyde (OPA)-l-thio-β-d-glucose as derivatization agent.
• 2.2. Fourteen primary amino acids were detected among which glutamine, alanine, γ-aminobutyric acid (GABA) and glycine predominated and constituted 67.7% of the amino acids found.
• 3.3. The concentration of GABA increased significantly with the age of larvae entering the wandering phase and reached a maximum during metamorphosis.
• 4.4. Analysis of cold-acclimated larvae revealed a net increase of free primary amino acids from 96 to 151.8 μmol/ml during consecutive acclimation to 0°C within 20 days and to 205.4μmol/ml during cold shock injury at 0°C (3 hr).
• 5.5. The bulk of this increase was accounted for by alanine, glycine, phenylalanine and lysine.

     

Purification of endo- and exolaminarinase and partial characterization of the exoacting form from the copepod acartia clausi (Giesbrecht, 1889)

• 1.1. The copepod Acartia clausi exhibited two laminarinases (exo- and endo-acting forms) purified by gel chromatography followed by affinity chromatography. Specific antibodies have been raised against the purified exolaminarinase antigen.
• 2.2. A single band of protein appeared on a polyacrylamide disc gel electrophoresis; its mol. wt is 21,000.
• 3.3. Biochemical properties of the purified enzyme showed a maximum activity at pH 5.2 and a temperature of 40°C with laminarin as substrate. The thermal stability of the enzyme and the effect of various cations on its activity were examined. The enzyme hydrolyses specifically the β(1–3) linked polysaccharides and had no activity against the α(1–4) or β(1–4) disaccharides or polysaccharides.
• 4.4. The kinetic parameters V_m and K_m vary with the temperature; the affinity constant (K_a) was maximum between 25–30°C. The Arrhenius plot defined two values of energy of activation: 7980 cal/mole and 17,506 cal/mole.
• 5.5. From the purification scheme the exoacting form appears to be largely dominant over the endoacting form.

     

The reproduction strategy of oyster ostrea edulis L. from the biochemical point of view

• 1.1. Influence of the biochemical composition of food (four species of micro-algae and one mixture) on the biochemical composition of gonads and larvae of O. edulis (total protein, lipid, carbohydrate, ash content, neutral and polar lipid class composition, amino acid composition and fatty acid composition of total, neutral and polar lipids) and the size of newly released larvae have been investigated.
• 2.2. Precentage of total lipids and triacylglycerols in gonads depends on that in algae (r = 0.52 and 0.69 accordingly).
• 3.3. Gonads rich in lipids had a higher level of triacylglycerols, phospholipids, polar lipids and a lower value of the ratio phosphatidylethanolamine/phosphatidylcholine (PE/PC) than gonads with a low lipid content.
• 4.4. Amino acid composition of gonads depends on that of food, in this case, essential acids are preferentially accumulated (Asp acid, Ser, Ala, Cys, Tyr and Pro) and two non-essential (Thr and Lys).
• 5.5. Fatty acid composition of total lipids of gonads was rather stable; except for the two essential acids 20:523 and 22:6w3, their percentage depends on that of food r = 0.65 and 0.65 accordingly). Fatty acid composition of neutral lipids was more diverse (in number and degree of variety) as compared to polar lipids.
• 6.6. Larvae released from oysters with gonads rich in lipids had a higher percentage of lipids, triacylglycerols, size and a lower ash percentage and value of ratio PE/PC, as compared to larvae from gonads with low lipid content. Total lipid and triacylglycerol contents in gonads correlate rather well with those in larvae (r = 0.77 and 0.47 accordingly).
• 7.7. Phospholipid class composition of larvae strongly depends on that of gonads. All the correlations are high and positive in character (except for phosphatidylinositol).
• 8.8. Amino acid composition of larvae depends on that of gonads and, as in the case with gonads, the same essential acids are accumulated in the first place.
• 9.9. Fatty acid composition of total lipids of newly released larvae was rather stable and independent on that of gonads except for total polyunsaturated acids (r = 0.70) and 20:5w3 (r = 0.65). Fatty acid composition of neutral lipids was lesser diverse (in number and degree of variation) as compared to polar lipids.

     

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.

     

The calcium uptake by larvae of the oyster,Crassostrea virginica,and the clam,Mulinia lateralis

• 1.1. The uptake of calcium by larvae of the oyster (Crassostrea virginica) and the clam (Mulinia lateralis) was measured using the ⁴⁵Ca isotope tracer method.
• 2.2. An equation was established for the calculation of true calcium uptake and the rates expressed as ng Ca/larva/hr were 0.39 and 0.34 ± 0.16 (n = 4) for 3- and 11-day-old oyster larvae, and 0.03 and 0.15 for 7- and 9-day-old clam larvae, respectively.
• 3.3. This system is sensitive, rapid, simple and potentially useful for the measurements of calcium metabolism, shell formation, aquaculture and toxicity.

     

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.

     

Characterization of spore coat proteins of Bacillus thuringiensis and Bacillus cereus

• 1.1. Spore coat extracts from Bacillus thuringiensis subspecies kurstaki and israelensis and Bacillus cereus T and B. cereus NRRL 569 were characterized by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and by amino acid analysis.
• 2.2. Both B. cereus spore coats had similar electrophoretic profiles.
• 3.3. The B. thuringiensis spore coats contained crystal proteins as major components as well as lower mol. wt proteins.
• 4.4. B. thuringiensis subsp. israelensis had a unique coat protein profile which was different from B. cereus and B. thuringiensis subsp. kurstaki coats.
• 5.5. Insecticidal activity of spores against the tobacco hornworm, Manduca sexta, and the mosquito, Aedes aegypti, also was determined.
• 6.6. B. thuringiensis subsp. kurstaki spores were lethally toxic to the tobacco hornworm (Lepidoptera) larvae, whereas spores of the other subspecies were not.
• 7.7. Except for subspecies israelensis, none of the spores was effective against the mosquito (Diptera) larvae.

     

Binding of cadmium and copper in the mayfly Baetis thermicus larvae that inhabit a river polluted with heavy metals

• 1.1. The larvae of mayflies (Baetis thermicus) that inhabited a metal-contaminated river (the river Mazawa in Yamagata, Japan) were collected and the concentrations of several heavy metals in mayflies were compared with those inhabiting a river not contaminated with metals.
• 2.2. Cadmium, copper and zinc in mayflies of the contaminated river were 13.4, 18.4 and 15.6 times higher in concentration than those in the non-contaminated river.
• 3.3. Distributions of the three metals in the supernatants of the larvae collected from the contaminated and non-contaminated rivers were determined by HPLC-atomic emission spectrometry with inductively coupled argon plasma.
• 4.4. Cadmium and copper in the supernatant of the larvae collected from the contaminated river were sequestered by metal-binding components induced for the respective metals, while zinc seemed to be bound loosely to native components.

     

The effect of high salinity on development,mortality and ray number of Echinaster spinulosus (Echinodermata: Asteroidea) at different developmental stages

• 1.1. Embryos and larvae of the asteroid Echinaster spinulosus were exposed to high salinity stress at various stages during early development.
• 2.2. Highest percentages of three-rayed (9.7%) and four-rayed (29%) individuals occurred when individuals which had developed for 48 hr (appearance of pre-oral lobe) at ambient salinity (30%o) were exposed to high salinity (39%o).
• 3.3. The percentage of ray-number aberrancies increased with increasing salinity.
• 4.4. The ontogenetic events associated with the formation of the hydrocoelic rudiments at the pre-oral lobe stage may be sensitive to salinity and influence the development of ray number.
• 5.5. The ability to induce variations of ray number in asteroids with salinity stress may yield an experimental approach for the determination of the adaptive significance of ray number in asteroids.

     

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.

     

Anhydrobiosis in nematodes—I. The role of glycerol myo-inositol and trehalose during desiccation

• 1.1. The concentrations of free glycerol, inositol and trehalose in five species of nematodes were determined. Analyses of total inositol content were also made.
• 2.2. Significant differences in free and bound sugar levels were found between the two good anhydrobiotes Anguina tritici and Ditylenchus dipsaci and the three poor survivors Pangrellus redivivus, D. myceliophagous and Turbatrix aceti.
• 3.3. Highest trehalose contents were found in desiccated A. tritici and D. dipsaci, but glycerol levels were low.
• 4.4. P. redivivus and T. aceti contained high concentrations of free glycerol.
• 5.5. Desiccated A. tritici larvae contained more free and bound inositol than all other species studied, but desiccated D. dipsaci larvae had higher levels of bound inositol than P. redivivus, D. myceliophagous and T. aceti.
• 6.6. Dramatic reductions in inositol and trehalose contents were found in revived A. tritici larvae and freshly extracted D. dipsaci larvae. This was accompanied by an increase in glycerol content.
• 7.7. The results are discussed in relation to the possible biochemical adaptations employed by anhydrobiotes during desiccation.

     

Dose-dependent incorporation of orally infused [1-14C]oleic acid into the lipid classes of midgut,haemolymph and fat body of dragonfly larvae (Aeshna cyanea)

• 1.1. Five different doses of radioactive oleic acid (ranging from 1.87 nmoles to 5.61 μmoles) were administered to Aeshna cyanea larvae.
• 2.2. Its incorporation into the midgut epithelium, haemolymph and fat body increased with the dose and time.
• 3.3. Low doses caused up to 95% phospholipid labelling in the midgut wall, while labelled triacylglycerol was less than 1%, but increased with the doses to a maximum of 68%. The data favour the glycerophosphate pathway of oleic acid esterification.
• 4.4. At low doses oleic acid was mainly released into the haemolymph from the midgut phospholipid pool, and at high doses from the triacylglycerol pool.
• 5.5. Diacylglycerol was the most heavily labelled lipid class of the haemolymph, amounting up to 98% and slightly decreasing with time.
• 6.6. The fat body showed a dose- and time-dependent increase in labelled phospholipid and triacyl-glycerol, maximally amounting to 14 and 90%, respectively.

     

The tolerance of lepidopterous larvae to an insect selective neurotoxin

The interaction of the fast-neurotoxic and insect selective polypeptide derived from scorpion venom (AaIT) with lepidopterous larvae tissues was studied through assays of toxicity, chromatography, binding and light microscopical autoradiography. The native and/or radioiodinated toxin was shown to:

• 1.(1) Induce a delayed, slow, progressive paralysis (within 24–48 h) of Spodoptera larvae by relatively high doses (paralytic unit = 2.4 μg/100 mg) corresponding to about only 10% of the total toxicity of the crude venom. Larvae of six species representing five families of Lepidoptera responded similarly to the toxin.
• 2.(2) Resist an in vitro incubation in the insect's hemolymph.
• 3.(3) Lose 80% of its toxicity in the insect's body within 24 h, accompanied by a progressive process of degradation and elimination by the excretory system.
• 4.(4) Specifically bind to a single class of non-interacting binding sites of high affinity and low capacity (0.2 pmol/mg protein, similar to tritiated saxitoxin) in an in vitro, homogenate derived, neuronal preparation.
• 5.(5) Specifically bind with high affinity to desheathed but otherwise intact nerves.
• 6.(6) Be devoid of accessibility to peripheral-terminal branches of Spodoptera motor nerves in situ—strongly contrasting those of the toxin susceptible Periplaneta nerves.

It may be thus concluded that the tolerance of the lepidopterous larvae to AaIT can be substantially attributed to pharmacokinetic aspects of toxin accessibility barriers and degradation processes.     

Purification and characterization of a blue-colored red-fluorescent protein from the silkworm (Bombyx mori L.) larvae

• 1.1. A red-fluorescent blue protein (P600) was purified from the digestive juice of the silkworm (Bombyx mori L.) larvae raised on mulberry leaves.
• 2.2. The purified protein was electrophoretically homogeneous and showed the absorption maxima at 601.5 nm and 278 nm, and the fluorescence maximum at 621 nm.
• 3.3. The molecular weight was estimated to be 540,000 by gel filtration on Sepharose CL-6B. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate suggests that the protein consists of two heterogeneous polypeptide subunits with a mol. wt of 15,000 and 18,000.
• 4.4. The P600 contains excess acidic amino acid residues over basic groups. The polarity and pI were 45.5% and 4.6, respectively.
• 5.5. The production of H₂O₂ was observed in the presence of P600 upon illumination.