[Radiochemistry of the dynamic functioning of neurosecretory cells of the median protocerebralis of Locusta migratoria (Insecta, Orthoptera) after electrostimulation].
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Animals↗
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Abdominal production of ecdysterone and pupal-adult development in Tenebrio molitor (Insecta, Coleoptera).
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Abdomen↗
Differential responsiveness of phosphorylase system and fat body carbohydrates of Poecilocerus pictus (Insecta) to hyperglycemic factors of crab (Crustacea) and scorpion (Arachnida).
Injection of hyperglycemic factors obtained from crab (Oziotelphusa senex senex) and scorpion (Heterometrus fulvipes) showed different effects on fat body phosphorylase activity and levels of total carbohydrates and glycogen in the grasshopper (Poecilocerus pictus). The former hyperglycemic principle phosphorolates glycogen whereas the latter does not.
Adipose Tissue↗
Characterization of three hydroxylases involved in the final steps of biosynthesis of the steroid hormone ecdysone in Locusta migratoria (Insecta, Orthoptera).
It is most generally accepted that the last three enzymatic reactions in the biosynthetic pathway of ecdysone are, in this order, the hydroxylations at positions C-25, C-22 and C-2. Using high specific activity tritiated ecdysone precursors (2,22,25-trideoxyecdysone, 2,22-dideoxyecdysone and 2-deoxyecdysone) we have characterized the hydroxylases involved in these reactions, in the major biosynthetic tissue of ecdysone, i.e. the prothoracic glands. We show that C-2 hydroxylase is a mitochondrial oxygenase which differs from conventional cytochrome P-450-dependent monooxygenases by its relative insensitivity to CO. In contrast, C-22 and C-25 hydroxylases appear as classical cytochrome P-450 monooxygenases; C-22 hydroxylase is a mitochondrial enzyme whereas our data point to a microsomal localization of the C-25 hydroxylase.
Animals↗
Morphometric comparison of the midgut epithelial cells in male and female Aedes aegypti L. (Insecta, Diptera).
Midgut epithelial cells of male and female Aedes aegypti, 3 days after emergence, were compared morphometrically. The results of the present investigation concerning the female, are in good agreement with those of a previous study (Hecker et al., 1974), demonstrating that morphometric investigation of midgut epithelia in A. aegypti can successfully be reproduced, and that the mosquito strain used did not show quantitative morphological changes due to laboratory rearing. In males, the cells of the anterior (A) and posterior part (P, 'stomach') of the midgut differ in their quantitative composition. Higher values are found for the microvilli and for the basal labyrinth in the A-part. On the other hand a higher volume density of the mitochondria is present in the P-part. No significant differences are found in the A-part between males and females. Significant differences, however, are present in the P-part. Distinctly more rer in the female stomach can be correlated with the synthesis of enzymes for blood digestion, which are absent in the male. In addition, the more complex functions of the female P-part are also reflected by higher values for other organelles and membrane systems (e.g. mitochondria, basal labyrinth).
Aedes↗
Morphine analgesia, tolerance and addiction in the cricket Pteronemobius sp. (Orthoptera, Insecta).
The escape reaction time (ERT) of the cricket Pteronemobius sp. from the heated box begins at 48 degrees and increases with temperature until 56 degrees C, beyond which there is no further increase. The ERT (2.2 +/- 1.39 s) from the hot box at 54 degrees C is used as a model for studying the analgesic effects of opiates. Results of the present paper show that the ERT did not change after injecting the insect in the abdominal haemocoel with 0.9% saline solution, but ERT increased when 0.32, 0.52 or 0.69 mg/g of morphine is injected in the same place. The maximum ERT increase is reached at 90 min after drug injection, and the drug effect disappears 3 h after the injection. At 90 min after drug injections, the dose of 0.50 mg/g of morphine produces 50% of ERT increase, and it is referred to as the median analgesic dose (D50). 1.05 mg/g of morphine produces an ERT longer than 30 s that results in an irreversible damage to the insect. Sixty-four micrograms/g of naloxone given in addition to D50 of morphine fully blocked the effect of morphine during its 3-h action. However, more than 64 micrograms/g of naloxone alone also increase the ERT in the cricket, similar to what has been described for vertebrates. Four daily morphine injections of D50 decreased ERT in such a way that, at the fourth day, the ERT is similar to the ERT produced by saline solution; i.e., tolerance is shown. The suppression of daily morphine injections of D50 during the fifth day produced a hyperresponse to vibration (big jumps) not shown in the case of the injections of saline solution; i.e., addiction is shown.
Analgesia↗
Effects of subacute doses of cadmium on pH-stressed Leptophlebia marginata (L.) and Baetis rhodani Pictet (Insecta: Ephemeroptera).
Cd uptake, emergence, survival and locomotory activity at two pH levels were studied in a 27-day experiment with Leptophlebia marginata and in a 19-day experiment with Baetis rhodani. Model ecosystems containing recirculating stream water, patches of sediment and leaves, simulated a natural stream. During the experiments, concentrations of Al, Cd, Fe and Zn increased in the water at pH 5, while conductivity decreased. Cd was taken up by both species at a rate which indicated linear uptake kinetics. No steady state of Cd in the animals was observed. The larvae of B. rhodani contained significantly more Cd than the adults (p<0.001). Uptake of Cd by Baetis rhodani was higher at pH 7 than at pH 5 (p<0.05). The survivial of L. marginata was not influenced by pH and Cd stress, but emergence was significantly reduced (p<0.05). The survival and the emergence of B. rhodani were reduced by low pH and also by Cd addition (p<0.01). At pH 7, Cd had no significant adverse effect on survival. Locomotory activity of Baetis rhodani was reduced by low pH and additionally by Cd stress.
Journal Article↗
Relation of the second messenger system to the electrogenesis and regulation of the contraction in the heart cell membrane of insecta.
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Action Potentials↗
Brain RNA synthesis and the retention of learning through metamorphosis in Tenebrio obscurus (Insecta: Coleoptera).
1. Neurochemical events associated with the retention of learning through metamorphosis in the tenebrionid beetle, Tenebrio obscurus, were investigated. 2. Retention of learning of a complex maze task was demonstrated for this species. 3. Learning was accompanied by a significant increase in RNA synthesis within the corpora pedunculata of both larval and adult stages of this holometabolous insect. 4. The implications of these results to the development of the insect CNS during various life cycle stages and the conservation of neural organization within those brain regions associated with the consolidation and storage of experiential information are discussed.
Animals↗
Sheathed nuclear division in primary spermatocytes of Orgyia antiqua (Lepidoptera, Insecta).
The restructuring of spermatocytes during the first meiotic division is examined in the moth Orgyia antiqua (Lymantriidae, Lepidoptera) using transmission electron microscopy. Particular emphasis was placed on the behaviour of the perispindle membrane system. These membranes develop from layers of smooth endoplasmic reticulum wrapped around the prophase I nucleus and are retained until early telophase I. The original nuclear envelope is dissolved in metaphase I. Polar fenestrae in the perispindle membrane stacks are filled with numerous irregular membrane elements. The formation of new nuclear envelopes around the daughter nuclei takes place inside the perispindle membrane system. Finally, the membrane stacks rupture concomitantly with spindle elongation in late telophase I. Thus, division of primary spermatocytes in Orgyia antiqua has a surprising degree of similarity with the so-called closed mitosis. This mode of division is typical for many protozoa, algae and fungi. In the pertinent cells, the original nuclear envelope persists around the spindle area during nuclear division. In order to distinguish the closed mitosis from the situation in Orgyia antiqua spermatocytes, the term 'sheathed nuclear division' is suggested for the latter.
Animals↗
Ethanolamine oxidase from the blowfly, Phormia regina (Diptera: Insecta).
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Animals↗
The comparative biochemistry of invertebrate mucopolysaccharides-V. Insecta (Calliphora erythrocephala).
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Animals↗
Functional multiplicity and structural correlations in the hemoglobin system of larvae of Chironomus thummi thummi (Insecta, Diptera): Hb components CTT I, CTT II beta, CTT III, CTT IV, CTT VI, CTT VIIB, CTT IX and CTT X.
Larvae of the dipteran insect Chironomus thummi thummi that burrow in fresh-water muds, contain at least 12 hemoglobin (Hb) components of which the functional properties have not been systematically documented, although their amino acid sequences have been elucidated, showing mutually distinct primary structures. We isolated eight components (the monomeric Hbs CTT I, CTT III and CTT IV and the dimeric Hbs CTT II beta, CTT VI, CTT VIIB, CTT IX and CTT X) and measured in each O2 affinity and cooperativity and their pH dependence, and the effects of temperature, NaCl and ATP. The O2 affinities, Bohr- and temperature effects of the isohemoglobins are discussed in relation to mode of life and the microenvironmental conditions to which the larvae are subjected in nature, and with regard to the molecular mechanisms underlying the Hb-oxygenation reactions.
Animals↗
Low allozyme variability in Bactrocera albistrigata (Insecta: Diptera: Tephritidae) from Peninsular Malaysia.
1. Population samples of Bactrocera albistrigata from Peninsular Malaysia were analyzed for 12 to 14 gene-enzyme systems comprising 15-18 loci. 2. Three loci, aMDH, PGD and PGM, were polymorphic. 3. Anodal malate dehydrogenase and phosphogluconate dehydrogenase were represented by two alleles each, while phosphoglucomutase was represented by three alleles. 4. Phosphoglucomutase had a higher heterozygosity than anodal malate dehydrogenase and phosphogluconate dehydrogenase. 5. B. albistrigata was characterized by low genetic variability, as measured by the proportion of polymorphic loci and heterozygosity.
Alleles↗
Neurons reactive to antibodies against serotonin in the stomatogastric nervous system and in the alimentary canal of locust and crickets (Orthoptera, Insecta).
Immunoreactive neurons in the stomatogastric nervous system and in the alimentary tract of the locust Schistocerca gregaria and the crickets Gryllus bimaculatus and Acheta domesticus have been examined using antibodies against serotonin (5-hydroxytryptamine; 5-HT). For comparative anatomical analysis cobalt chloride infusion was applied. The innervation of the visceral muscles was studied electron microscopically. In all three species the majority of the 5-HT-immunoreactive cell bodies of the stomatogastric nervous system occur in the frontal ganglion in which 30-40% of the total number of cell bodies react with anti-5-HT. In the occipital ganglion only two to four cell bodies (1-2%) are 5-HT-immunoreactive. Single immunoreactive cell bodies were observed in the ventricular ganglia in only a few preparations. The 5-HT-immunoreactive neurons in the frontal ganglion are pseudounipolar or multipolar. The main process of the 5-HT-immunoreactive neurons of the frontal ganglion descend along the entire stomatogastric nervous system. Some arborizations of these processes ascend into the brain and others supply the neuropil of all stomatogastric ganglia. Side branches leave the stomatogastric nervous system and form a plexus along the surface of the entire intestinal tract from where 5-HT-immunoreactive fibers supply: all muscle layers of the muscularis; the external dilator muscles of the foregut and probably some somatic muscles, neurohaemal organs and Malpighian tubules (excretory system). Serotonin-immunoreactive fibers further proceed into salivary gland and the retrocerebral complex (corpora cardiaca and corpora allata). The retrocerebral glandular complex and the hindgut receive additional immunoreactive neurons from the central nervous system. Electron microscopic analysis of nerves innervating the muscle layers of the alimentary tract revealed one type of 5-HT-immunoreactive and one or two types of non-5-HT-immunoreactive fibers. All fiber types contact the sarcolemma of muscle fibers without any obvious synaptic membrane specializations. The 5-HT-immunoreactive fibers are in some regions in close contact with the haemolymph. These regions can be regarded as sites of neurohormonal release. The distribution of serotonin-immunoreactive neurons suggests that 5-HT acts as a neurotransmitter and/or modulator on intestinal muscles and some somatic muscles and glandular cells, and as a neurohormone released from neurohaemal sites into the body fluid.
Animals↗
Qualitative and quantitative studies on the compounds of the larval defensive secretion of Zygaena trifolii (Esper, 1783) (Insecta, Lepidoptera, Zygaenidae).
Beside the known existence of cyanoglucosides (linamarin and lotaustralin) and proteins the neurotoxin beta-cyanoalanine has been demonstrated for the first time in the defensive secretions of animals. It is proposed that beta-cyanoalanine is produced by metabolizing cyanide from the cyanoglucosides. The methanolic precipitated protein fraction contains high amounts of aspartic acid, glycine, alanine, leucine and serine, thus being similar to the composition of larval silks in Lepidoptera. The defensive secretion contains 85% water, 8% proteins, 7% cyanoglucosides, 0.3% beta-cyanoalanine and beta-glucosidase while beta-cyanoalanine-synthetase could only be detected in the haemolymph.
Alanine↗
Purification and primary structure of ceratotoxin A and B, two antibacterial peptides from the female reproductive accessory glands of the medfly Ceratitis capitata (Insecta:Diptera).
In the present article we report the purification and the amino acid sequence of two antibacterial peptides present in the secretion of the female reproductive accessory glands of the dipteran insect Ceratitis capitata. Both peptides consist of 29 amino acid residues, are heat stable, strongly basic and differ from each other for the substitution of two amino acids. Their primary sequence and predicted secondary structure are related to other families of peptides known to have lytic and/or antibacterial activity. We propose the name ceratotoxins (from Ceratitis) for these antibacterial peptides.
Amino Acid Sequence↗
The ultrastructure of the prothoracic gland/corpus allatum/corpus cardiacum ring complex of the Australian sheep blowfly larva Lucilia cuprina (Wied.) (Insecta: Diptera).
The ultrastructure of the constituent endocrine glands within the ring complex of Lucilia cuprina larvae has not been previously described. This study investigated the ring complex of mid-third instar larvae. Three distinct endocrine cell types were identified: (1) prothoracic gland (PTG) cells which constituted the major cell type; (2) corpus allatum (CA) cells, localized in the anterior central region, and (3) corpus cardiacum (CC) cells, located posteriorly, ventral to the aorta. PTG cells were identifiable by their large ovoid nuclei (9-14 microns dia, length 12-18 microns) and numerous cytoplasmic lipid vacuoles. The plasma membrane of peripheral PTG cells were invaginated to form intercellular channels. The CA cells are characterized by ovoid nuclei (6-7.5 microns dia, 6.5-9 microns length) and electron dense staining cytoplasm. Compared to PTG cells the CA cells had smaller nuclei and lower nucleus:cytoplasm cell ratio. Extensive networks of highly irregular, electron-lucent intracellular spaces, dispersed throughout the cytoplasm were also characteristic of CA cells at this developmental stage. These spaces often contained membrane bound lipid vacuoles occurring singly or as aggregates. The CC contained both intrinsic and extrinsic neural components. The intrinsic cells were characterized by circular nuclei (6.5-8.5 microns dia), prominent nucleolus and numerous cytoplasmic electron-dense neurosecretory granules (100-240 nm dia). The extrinsic axons and terminals within the CC contained electron-dense neurosecretory granules (80-150 nm), neurotubules and mitochondria.
Animals↗