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Resistant potato selections contain leptine and inhibit development of the Colorado potato beetle (Coleoptera: Chrysomelidae).

We recently described a new source of host-plant resistance to the Colorado potato beetle, Leptinotarsa decemlineata (Say), in a tetraploid potato (Solanum tuberosum L.) selection, ND2858-1. This genotype, and selected backcross progeny, had little damage while check cultivars were defoliated in open-choice field assays. To further characterize the observed deterrence, we determined foliar glycoalkaloids and conducted no-choice assays with ND2858-1 backcross progeny genotypes (ND4382-n). Development of neonate L. decemlineata in detached leaf assays on resistant progeny genotypes was delayed and larval weight gain after 4 d was inhibited by 75% relative to larval development and weight gain on susceptible genotypes. Inhibition of larval development in detached leaf assays with the selected progeny genotypes was equivalent to that of high-leptine genotypes of S. chacoense Bitter. Foliar glycoalkaloids of resistant genotypes included low levels of leptines I and II. The unlikely nature of this cross and the presence of leptine in this and resistant progeny selections cast doubt on the recorded pedigree. Molecular analyses were conducted by restriction fragment-length polymorphism and amplified fragment-length polymorphisms. Both methods established a high degree of relatedness to S. tuberososum and S. chacoense but not to S. fendleri. We conclude that ND2858-1 did not originate from a cross with S. fendleri, but is likely derived from S. chacoense. Oviposition and larval survival were reduced when adult L. decemlineata were placed in cages with resistant genotypes; an effect that was enhanced by inclusion of Perillus bioculatus F. Therefore, the nonpreference previously observed in open-choice field defoliation assays is also associated with antibiotic effects on L. decemlineata. The resistance may be caused by leptines, but is greater than would be expected by the leptine content. This source of host plant resistance could be a cost-effective management strategy, especially if combined with other resistance mechanisms or compatible control measures to delay development of resistance in the target insects.

Animals↗

Ontogeny of pituitary adenylate cyclase-activating polypeptide (PACAP) in the frog (Rana ridibunda) tadpole brain: immunohistochemical localization and biochemical characterization.

The anatomic distribution and biochemical characteristics of the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) were investigated in the central nervous system of the frog, Rana ridibunda, during development. Three to four days after hatching, at stages IV-VII, PACAP-immunoreactive perikarya were detected in the dorsal thalamus within the anterior ventral area, and a few fibers were found in the medial pallium. Positive cell bodies were first observed in the hypothalamus at stages VIII-IX, at the level of the dorsal and ventral infundibular nuclei. In these regions, the number of positive perikarya increased during ontogeny. In tadpoles, during the mid- and late premetamorphosis, a more complex organization of the PACAP-immunoreactive system was found in the thalamus with the appearance, at stages IX-XII, of two additional groups of positive neurons in the ventrolateral area and posterocentral nucleus. At stages XIII-XVIII of larval development and subsequent larval stages, PACAP-immunoreactive fibers were found in the median eminence. In newly metamorphosed animals, several additional groups of positive perikarya appeared in the medial pallium, the preoptic nucleus, the torus semicircularis, the tegmentum of the mesencephalon, and the cerebellum. The immunoreactive peptide contained in the tadpole brain was characterized by high performance liquid chromatography analysis combined with radioimmunoassay quantification. At all stages investigated, the predominant form of PACAP-immunoreactive material coeluted with synthetic frog PACAP38. The occurrence of PACAP soon after hatching indicates that the peptide may exert neurotrophic activities. The existence of immunoreactive elements in several thalamic regions at mid- and late premetamorphic stages suggests that PACAP may act as a neurotransmitter, neuromodulator, or both, during ontogenesis. Finally, the presence of PACAP-immunoreactive perikarya in hypothalamic nuclei and nerve fibers in the median eminence supports the view that PACAP may play a role in the control of pituitary hormone secretion during larval development.

Age Factors↗

[Biological cycle of Cyrnea (Procyrnea) mansoni Seurat, 1914, a habronemid nematode parasite of birds of prey in Togo].

A habronemid nematode in birds of prey, Milvus migrans Bonaparti and Accipiter badius Linné, in Togo, is identified as Cyrnea (Procyrnea) mansioni (Seurat, 1914). Larval development is experimentally studied in the orthopteran Acrididae Tylotropidius patagiatus Karsch. The first three larval stages are described and illustrated. The biology of this spiruroid nematode is distinguished by the unusual rapidity of larval development (infective larvae at 10 days). Comparison of the life cycle of C. mansioni with life cycles of other Habronemid Nematodes parasitizing birds, points out an evolution of larvae from primitive forms of large size and slow development to evolved forms of small size and rapid development. Observations concerning the encapsulation of infective larvae in the intermediate host confirm this larval evolution.

Animals↗

Plasticity of auditory medullary-midbrain connectivity across metamorphic development in the bullfrog, Rana catesbeiana.

On the basis of patterns of anterograde, retrograde, and bi-directional transport of tracers from both the superior olivary nucleus (SON) and the torus semicircularis (TS), we report anatomical changes in brainstem connectivity across metamorphic development in the bullfrog, Rana catesbeiana. In early and late stages of larval development (Gosner stages 25-37), anterograde or bi-directional tracers injected into the SON produce terminal/fiber label in the contralateral SON and in the ipsilateral TS. Between stages 38-41 (deaf period), only sparse or no terminal/fiber label is visible in these target nuclei. During metamorphic climax (stages 42-46), terminal/fiber label reappears in both the contralateral SON and in the ipsilateral TS, and now also in the contralateral TS. Injections of retrograde tracers into the SON fail to label cell bodies in the ipsilateral TS in deaf period animals, mirroring the previously-reported failure of retrograde transport from the TS to the ipsilateral SON during this developmental time. Bilateral cell body label emerges in the dorsal medullary nucleus and the lateral vestibular nucleus bilaterally as a result of SON transport during the late larval period, while cell body label in the contralateral TS emerges during climax. At all larval stages, injections into the SON produce anterograde and retrograde label in the medial vestibular nucleus bilaterally. These data show anatomical stability in some pathways and plasticity in others during larval development, with the most dramatic changes occurring during the deaf period and metamorphic climax. Animals in metamorphic climax show patterns of connectivity similar to that of froglets and adults, indicating the maturation during climax of central anatomical substrates for hearing in air.

Animals↗

Gonadal development of larval male Xenopus laevis exposed to atrazine in outdoor microcosms.

The potential effects of atrazine on gonadal development in metamorphs and subadults of the African clawed frog (Xenopus laevis) were studied under conditions of natural photoperiod and temperatures in outdoor microcosms from August 2002 to June 2003 in South Africa. Triplicate 1100 L microcosms for each nominal concentration of 0.0, 1, 10, and 25 microg of atrazine/L were used. Measured atrazine concentrations varied <25% throughout the study, and no atrazine was detected in the control microcosms. Tadpoles developed well at all concentrations. On the basis of histological examination of testes of recently metamorphosed stage 66 frogs, 57% of the individuals in the reference group exhibited testicular oocytes as compared with 57, 59, and 39% of the 1, 10, and 25 microg/L atrazine groups, respectively. The average prevalence of testicular oocytes for all of the treatments including the controls was 54% in a single testis, while, in 35% of individuals, testicular oocytes were observed in both testes. The number of testicular oocytes per individual ranged from 0 to 58 with means of 9.5, 9.8, 8.5, and 11.1 forthe 0.0, 1, 10, and 25 microg of atrazine/L groups, respectively. Ten months after metamorphosis, another subset of juveniles was examined, and the maximum number of testicular oocytes observed was five in one animal. The presence of testicular oocytes was not related to exposure to atrazine and may be a natural phenomenon during ontogeny.

Animals↗

Role of specific activators of intestinal amino acid transport in Bombyx mori larval growth and nutrition.

Nutrient absorption and its modulation are critical for animal growth. In this paper, we demonstrate that leucine methyl ester (Leu-OMe) can greatly increase the activity of the transport system responsible for the absorption of most essential amino acids in the larval midgut of the silkworm Bombyx mori. We investigated leucine uptake activation by Leu-OMe in brush border membrane vesicles and in the apical membrane of epithelial cells in the midgut incubated in vitro. Moreover, the addition of this strong activator of amino acid absorption to diet significantly affected larval growth. Silkworms fed on artificial diet supplemented with Leu-OMe reached maximum body weight 12-18 h before control larvae, and produced cocoon shells up to 20% heavier than those of controls. The activation of amino acid absorption plays an essential role in larval development so that larval growth and cocoon production similar to controls reared on an artificial diet with 25% of dry mulberry leaf powder were observed in silkworms fed on an artificial diet with only 5% of mulberry powder. Arch.

Amino Acid Transport Systems, Basic↗

Development of PDF-immunoreactive cells, possible clock neurons, in the housefly Musca domestica.

Even though the housefly Musca domestica shows clear circadian rhythms in its behavioural and physiological processes, a circadian pacemaker system controlling these rhythms has not yet been described morphologically in this species. In M. domestica, neurons immunoreactive to pigment-dispersing factor (PDF), a neurotransmitter/neuromodulator of circadian information arising from a circadian clock and transmitted to target cells, are similar in their number and distribution to the PDF neurons of Drosophila melanogaster. In D. melanogaster these neurons co-localize PER protein and have been identified as clock neurons in that species. Here we report PDF-immunoreactive cells in the housefly's brain during postembryonic development in the larval and pupal stages, as well as in the adult fly soon after eclosion. In the housefly's brain, there are three groups of PDF-immunoreactive neurons: two groups with small (sPDFMe) and large (lPDFMe) cell bodies in the proximal medulla of the optic lobe; and one group in the dorsal protocerebrum (PDFD). Three out of four sPDFMe can be detected during the first hour of larval development, but the fourth sPDFMe is observed in the larva only from 48 hours after hatching, along with five lPDFMe neurons, seen first as two subgroups, and three out of four PDFD neurons. During postembryonic development these neurons show changes in their structure and immunoreactivity. New PDF neurons are observed during pupal development but these neurons mostly do not survive into adulthood. In the adult fly's brain, the PDF neurons have also been examined in double-labelled preparations made with a second antibody directed against the product of one of several clock genes: period (per), timeless (tim), or cryptochrome (cry). Among them, only immunoreactivity to CRY-like protein has been detected in the brain of M. domestica and has shown a daily rhythm in its concentration, as examined immunocytochemically. CRY was co-localized with PDF in the sPDFMe of the housefly's brain fixed during the day. The possibility that the sPDFMe neurons are the housefly's clock neurons is discussed.

Animals↗

Volatile emissions from Aesculus hippocastanum induced by mining of larval stages of Cameraria ohridella influence oviposition by conspecific females.

Larval stages of the horse chestnut leafminer Cameraria ohridella can completely destroy the surface of horse chestnut leaves, Aesculus hippocastanum. This study investigated the effect of the degree of leaf browning caused by the insect's larvae on olfactory detection, aggregation, and oviposition of C. ohridella adults. The influence of A. hippocastanum flower scent on oviposition of the first generation was also evaluated. Utilizing gas chromatography coupled with parallel detection by mass spectrometry and electroantennography (GC-MS/EAD), more than 30 compounds eliciting responses from antennae of C. ohridella were detected. Oviposition and mining by C. ohridella caused significant changes in the profile of leaf volatiles of A. hippocastanum. After oviposition and subsequent mining by early larval stages (L1-L3), substances such as benzaldehyde, 1,8-cineole, benzyl alcohol, 2-phenylethanol, methyl salicylate, (E)-beta-caryophyllene, and (E,E)-alpha-farnesene were emitted in addition to the compounds emitted by uninfested leaves. Insects were able to detect these compounds. The emitted amount of these substances increased with progressive larval development. During late larval stages (L4, L5) and severe loss of green leaf area, (E,E)-2,4-hexadienal, (E/Z)-linalool oxide (furanoid), nonanal, and decanal were also released by leaves. These alterations of the profile of volatiles caused modifications in aggregation of C. ohridella on leaves. In choice tests, leaves in early infestation stages showed no significant effect on aggregation, whereas insects avoided leaves in late infestation stages. Further choice tests with leaves treated with single compounds led to the identification of substances mediating an increase or decrease in oviposition.

Aesculus↗

The Zona Pellucida domain containing proteins, CUT-1, CUT-3 and CUT-5, play essential roles in the development of the larval alae in Caenorhabditis elegans.

The alae, longitudinal ridges of the lateral cuticle, are the most visible specialization of the Caenorhabditis elegans surface. They are present only in L1 and dauer larvae and in adults. Little is known about the mechanisms through which at the appropriate stages secretion of cuticle components by the seam cells results in the formation of the alae. Here we show that three proteins, each containing a Zona Pellucida domain (ZP), are components of the cuticle necessary for larval alae development: CUT-1 and CUT-5 in dauer larvae and CUT-3 and CUT-5 in L1s. Transcriptional regulation of the corresponding genes contributes to the stage-specific role of these proteins. Larvae with reduced cut-1, cut-3 or cut-5 function not only lack alae but are also larger in diameter due to an increase in the width of the lateral cuticle. We propose a model in which reduction of the body diameter, which occurs in normal L1 and dauer larvae, is the result of a dorso-ventral shrinking of the internal layer of the lateral cuticle and formation of the alae results from the folding of the external layer of the lateral cuticle over the reduced, internal one. Alae of adults appear to form through a different mechanism.

Animals↗

[Development of the gill system in early ontogenesis of Danio and nine spike stickleback].

We studied specific features of development of the gill system during ontogenesis of the zebrafish Danio rerio and ninespine stickleback Pungitius pungitius, which differ in the rates of gill system, development. Although the development of sticklebacks proceeds in nature at lower temperatures than for zebrafish, the rate of gill formation in the former is higher. These differences are related to the specific conditions in which these fish develop: embryonic and larval development of the stickleback proceeds in bodies of water with a lower oxygen content than for zebrafish, and this results in the adaptive alteration of the rate of gill system development. Differentiation of gills in the zebrafish is accompanied by a manifold increase in the oxygen consumption rate. At different developmental stages, the incremental rates of oxygen consumption and increase in the body mass of the zebrafish larvae and fry differed significantly.

Animals↗

Peptidergic innervation in the amphibian carotid labyrinth.

The amphibian carotid labyrinth, which corresponds to the mammalian carotid body and carotid sinus, is innervated by nerve fibers containing substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), FMRFamide (FMRF), and somatostatin (SOM). SP, CGRP, VIP, and NPY immunoreactive varicose fibers are more densely distributed in the peripheral portion of the carotid labyrinth than FMRF and SOM fibers. The time of appearance of SP, CGRP, and VIP is different for each. First CGRP fibers, then SP fibers appear at an early stage of larval development, and finally VIP fibres are detected at a later stage of larval development. Most SP fibres show coexistence with CGRP, and some SP fibres which show coexistence with NPY immunoreactivity are assumed to be continuous with those demonstrating VIP immunoreactivity. This indicates the possibility of coexistence of four different peptides in the same nerve fibers within the labyrinth. In various vasculatures of mammals, it has been shown that SP, CGRP, VIP, and NPY have a vasoactive nature in relation to the vascular smooth muscle cells. On this basis, it seems that the target of the peptidergic innervation in the amphibian carotid labyrinth is the smooth muscle cells which are abundantly distributed in the intervascular stroma. Accordingly, the peptidergic innervation may be involved in the vascular regulatory function of the labyrinth, although the possibility that these peptides participate in the chemoreception cannot be ruled out. In addition, the vascular regulatory function of the labyrinth may be modulated by the interaction of multiple neuropeptides.

Amphibians↗

Transcriptional regulation of atonal required for Drosophila larval eye development by concerted action of eyes absent, sine oculis and hedgehog signaling independent of fused kinase and cubitus interruptus.

Bolwig's organ is the larval light-sensing system consisting of 12 photoreceptors and its development requires atonal activity. Here, we showed that Bolwig's organ formation and atonal expression are controlled by the concerted function of hedgehog, eyes absent and sine oculis. Bolwig's organ primordium was first detected as a cluster of about 14 Atonal-positive cells at the posterior edge of the ocular segment in embryos and hence, atonal expression may define the region from which a few Atonal-positive founder cells (future primary photoreceptor cells) are generated by lateral specification. In Bolwig's organ development, neural differentiation precedes photoreceptor specification, since Elav, a neuron-specific antigen, whose expression is under the control of atonal, is expressed in virtually all early-Atonal-positive cells prior to the establishment of founder cells. Neither Atonal expression nor Bolwig's organ formation occurred in the absence of hedgehog, eyes absent or sine oculis activity. Genetic and histochemical analyses indicated that (1) responsible Hedgehog signals derive from the ocular segment, (2) Eyes absent and Sine oculis act downstream of or in parallel with Hedgehog signaling and (3) the Hedgehog signaling pathway required for Bolwig's organ development is a new type and lacks Fused kinase and Cubitus interruptus as downstream components.

Animals↗

Aging and development in social insects with emphasis on the honey bee, Apis mellifera L.

Honey bee colonies typically consist of about 20-40 thousand workers, zero to few thousand males (drones), depending on the time of year, and a single queen, the mother of the colony. Workers typically live 3-6 weeks during the spring and summer and can live about 4months during the winter. Queens are longer lived. Anecdotes of queens living 2-3years are not unusual, though they normally live less than a year in commercial hives. Little is known about the life span of drones. Queens develop from fertilized eggs that are not different from the eggs that develop into workers. Queens are, however, twice as large, have specialized anatomy, live much longer, and develop faster from egg to adult. All of these differences are derived from differences in larval rearing environment, primarily nutrition. The developmental trajectory of a female larva from worker into a queen can be determined as late as the third day of larval development, after this time the developmental pathway is fixed for a worker phenotype. The total time of larval development is only 5-6 days, therefore, just 2-3 days of differential feeding can lead to profound differences in development, and longevity. Workers undergo age development after they become adults. Workers usually initiate foraging behavior when they are 2-3 weeks old. The age at which a worker initiates foraging is a strong determinant of her length of life. This is presumed to be a result of the hazards of foraging, but natural senescence also occurs. Some bees remain in the nest and are never observed to forage, thereby outliving their forager sisters. Corresponding to this behavioral development are changes in the sizes of glands and the production of glandular products, increases in biogenic amine titers within the brain, an increase in the volume of specific regions of the brain, and changes in the neural system that affect perception of stimuli, and learning and memory. These age-related changes in behavior are regulated by intrinsic and extrinsic factors. Genetic variation has been demonstrated for many of these life history and behavioral traits. Selection and genome mapping studies have demonstrated relationships between the neural system, behavior, and life history traits.

Aging↗

Development of the musculature in the limpet Patella (Mollusca, Patellogastropoda).

Whole-mount technique using fluorescent-labelled phalloidin for actin staining and confocal laser scanning microscopy as well as semi-thin serial sectioning, scanning and transmission electron microscopy were applied to investigate the ontogeny of the various muscular systems during larval development in the limpets Patella vulgata L. and P. caerulea L. In contrast to earlier studies, which described a single or two larval shell muscles, the pretorsional trochophore-like larva shows no less than four different muscle systems, namely the asymmetrical main head/foot larval retractor muscle, an accessory larval retractor with distinct insertion area, a circular prototroch/velar system, and a plexus-like pedal muscle system. In both Patella species only posttorsional larvae are able to retract into the shell and to close the aperture by means of the operculum. Shortly after torsion the two adult shell muscles originate independently in lateral positions, starting with two fine muscle fibres which insert at the operculum and laterally at the shell. During late larval development the main larval retractor and the accessory larval retractor become reduced and the velar muscle system is shed. In contrast, the paired adult shell muscles and the pedal muscle plexus increase in volume, and a new mantle musculature, the tentacular muscle system, and the buccal musculature arise. Because the adult shell muscles are entirely independent from the various larval muscular systems, several current hypotheses on the ontogeny and phylogeny of the early gastropod muscle system have to be reconsidered.

Animals↗

Identification of two regions from the Drosophila decapentaplegic gene required for embryonic midgut development and larval viability.

The Drosophila decapentaplegic (dpp) gene, a member of the transforming growth factor-beta family, is required for dorsal/ventral pattern formation and midgut and imaginal disk development. We have identified a 3-kb upstream regulatory region necessary for dpp expression in the visceral mesoderm of the gastric caeca primordia and a second 2.5-kb upstream regulatory region necessary for dpp expression in the midgut visceral mesoderm corresponding to a portion of abdominal segments 1 and 2 (parasegment 7). These regulatory regions act over a distance of up to 10-kb on all four of the dpp promoters examined. Absence of dpp expression in the gastric caeca primordia caused defective development of the gastric caeca and a concomitant partial reduction in larval and pupal viability. Absence of dpp expression in the visceral mesoderm of parasegment 7 caused a reduction in the length of the central portion of the larval gut and a change in the morphology of the midgut cells in this region but had little effect on the survival of the animals to the adult stage. However, a larval lethal phenotype was observed when both the central portion of the larval midgut and the gastric caeca were defective.

Animals↗

Development of larval muscle properties in the embryonic myotubes of Drosophila melanogaster.

The entire developmental history of muscle membrane electrogenesis can be observed in the embryonic myotubes of Drosophila. We have examined the development of ionic currents and muscle properties using whole-cell patch-clamp techniques throughout embryonic myogenesis. In the early stages of myogenesis, from myoblast fusion through to establishing epidermal insertions, the myotubes are electrically inert and are electrically and dye coupled to adjacent myotubes. Membrane electrogenesis begins in the mid-embryonic stages (early stage 16), when the myotubes abruptly uncouple, revealing the first of five prominent extrajunctional currents: a small, inward, voltage-gated calcium current (ICa). The uncoupling of the embryonic myotubes heralds the onset of extremely rapid electrogenesis; within several minutes both the fast, inactivating (IA; Shaker) and delayed, noninactivating (IK) outward potassium currents, the stretch-activated outward potassium current, and the junctional glutamate-gated inward current all appear and begin to develop in a current-specific manner. Very late in embryogenesis (late stage 17), the calcium-dependent, outward potassium currents [rapid, inactivating (ICF; slowpoke) then delayed, noninactivating (ICS)] develop, completing the complement of macroscopic currents in the mature larval muscle. Hence, the voltage-gated currents (ICa, IA, and IK, respectively) appear relatively early, and the calcium-dependent currents (ICF, ICS) appear only very late during myogenesis. This developmental progression of current maturation is reflected in dynamic changes in the voltage responses of the embryonic membrane, from wholly passive response to current injection in the early, coupled myotubes to regenerating, overshooting action potentials in the mature embryonic muscle. The earliest embryonic IA current has a midpoint of inactivation 40 mV more negative than the IA current in the mature embryo. As myogenesis proceeds, the inactivation curve develops a biphasic character, suggesting that a low-inactivation IA channel is present in early development and progressively replaced by the mature form as development proceeds. The current at all stages can be completely eliminated in Shaker mutants (ShKS133). These findings suggest that an embryonic form of the Shaker IA channel is present during early myogenesis. The prominent IA current present in early development is almost entirely inactivated at the physiological resting potential; the significance and mechanism of this developmental shift are unclear.

Animals↗

Salvage and interconversion of purines in developing Artemia.

Incorporation of the radiolabelled purine bases adenine, guanine and hypoxanthine into acid soluble fraction, RNA and DNA nucleotides during the early larval development of Artemia sp. was studied. Adenine was the best precursor and guanine the poorest. The adenine phosphoribosyltransferase (APRT) activity was considerably higher than that of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and these activities did not significantly change throughout larval development. The pattern of purine interconversion was dependent on naupliar age. Conversion of [14C]adenine and [14C]hypoxanthine into guanine nucleotides increased with time of development. However, the conversion of [14C]guanine into [14C]adenine nucleotides was very low.

Adenine↗

[Specific features of digestive function development in larvae of some salmonid fish].

We studied the activities of digestive enzymes responsible for the digestion of food carbohydrate and protein components in plant-eating fish at various stages of larval development. The activities of all digestive enzymes tend to rise during larval development. Species specific features of the alimentary canal functioning have been described.

Animals↗