Structure and development of the larval central complex in a holometabolous insect, the beetle Tenebrio molitor

Wegerhoff, Rainer; Breidbach, Olaf

doi:10.1007/bf00318803

Cited by 70 publications

(70 citation statements)

References 43 publications

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“…We then determined that serotonin stimulated cAMP production by M. sexta Mt with an EC50 value of -0.14 ,tM but had essentially no effect on cAMP production by Mt of T. molitor even at 10 mM (K.F., data not shown). The stimulation of M. sexta Mt by this hydrophilic fraction is most likely due to serotonin, as immunohistochemical studies have shown a serotonin-like material in the brain (39,40), ventral nerve cord (41), and subesophageal ganglion (42) of T. molitor. There may be another biogenic amine present in T. molitor extracts that is responsible for the stimulation of cAMP secretion by T. molitor Mt. During the first LC purification step using a semipreparative column, two relatively hydrophobic fractions were observed which stimulated cAMP production in Mt of T. molitor (Fig.…”

Section: Discussionmentioning

confidence: 99%

Isolation and identification of a diuretic hormone from the mealworm Tenebrio molitor.

Furuya

Schegg

Wang

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

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A diuretic hormone of unusual structure was isolated from extracts of whole heads of the mealworm Tenebrio molitor. The hormone is a 37-aa peptide of 4371 Da, with the sequence SPTISITAPIDVLRKTWEQERARKQM-VKNREFLNSLN. This peptide increases cAMP production in Malpighian tubules of T. molitor. The amino acid sequence reveals that this peptide is a member of the family of sauvagine/corticotropin-releasing factor/urotensin I-related insect diuretic hormones. The C-terminal sequence of this peptide is quite different from other members of this family, which have a hydrophobic C terminus (isoleucinamide or valinamide). When aligned comparably, T. molitor diuretic hormone has a more hydrophilic C terminus, leucylasparagine (free acid). In contrast to all other known diuretic hormones of this family, this peptide has exceptionally low stimulatory activity on cAMP production in Malpighian tubules of Manduca sexta. However, at nanomolar concentrations it stimulates cAMP production in Malpighian tubules of T. molitor. Diuretic hormones of this family have been isolated previously from Lepidoptera, Orthoptera, Dictyoptera, and Diptera. This appears to be the first diuretic hormone isolated from a coleopteran insect.The regulation of water balance in insects has been heavily studied (1). With a variety of approaches, biologically active factors which promote urine production have been described from a large number of insect species (2). Recently, a number of insect diuretic hormones (DHs) have been isolated and characterized (3-9) which are homologous to a family of peptides including sauvagine, corticotropin-releasing factor (CRF), and urotensin. For simplicity, these DHs are referred to as the CRF-related DHs; all appear to act on the Malpighian tubules (Mt) via cAMP as second messenger (10). The leucokinins (11) and achetakinins (12), which were originally isolated as myotropic peptides, have been shown to stimulate fluid secretion from Mt (13), although this effect is not mediated via cAMP (14). Serotonin may also function as a DH; it stimulates fluid secretion by Mt of many insect species (14-18) and causes elevation of cAMP levels in Mt of some, but not all, of the stimulated species (14,16,(18)(19)(20).CRF-related DHs have now been isolated from four orders of insects, Lepidoptera, Orthoptera, Dictyoptera, and Diptera. coleopteran DH and preliminary results on its unusual biological activity. § MATERIALS AND METHODS Experimental Insects. T. molitor were kept under crowded conditions at 27°C on a 14 hr/10 hr light/dark cycle and were fed on bran and raw potatoes. Pupae were decapitated 24-48 hr after pupation. The heads were collected in liquid nitrogen and stored at -80°C until extraction. For the cAMP bioassay, Mt were taken from newly emerged adults of both sexes 3-12 hr after adult eclosion.Bioassay. DH activity in fractions from all purification steps was detected by the increase of cAMP in isolated Mt dissected from newly emerged adult T. molitor. Single Mt of T. molitor were incubated as described (5, 21...

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Section: Discussionmentioning

confidence: 99%

Isolation and identification of a diuretic hormone from the mealworm Tenebrio molitor.

Furuya

Schegg

Wang

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

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“…The determination of instars is possible with sensitive and specific mass fragmentographic method [13]. So, in the case of larvae stages, the results of earlier studies were used to identify instars [14,15]. In our study, the third instar (6.8±1.9 mm, mean ± SD), the eighth instar (7.8±1.3 mm, mean ± SD) and the last instar (20.4±1.2 mm, mean ± SD) were used.…”

Section: Life Cycle Of Mealworm Beetlementioning

confidence: 99%

Elemental Concentration in Mealworm Beetle (Tenebrio molitor L.) During Metamorphosis

Simon

Baranyai

Braun

et al. 2013

Biol Trace Elem Res

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Mealworm beetles have been used in numerous experiments as bioindicators. The aim of our experiment was to study the elemental composition in three larvae, pupae and first and second generation adult stages during their life cycle. We selected 180 larvae from a genetically similar population and put them in three groups, in two boxes (60 larvae in each box). Larvae were fed with mashed potato made of the same quality and quantity of potato powder. Then, we selected 10 individuals from each stage to the elemental analysis, using the ICP-OES method. The following elements were analysed in the studied stages: Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Sr and Zn. The results of principal component analysis demonstrated that based on elemental composition, different stages were separated with each other, but in the cases of the three larvae stages, high overlap was found. The results of the GLM ANOVA showed significant differences between the different stages of metamorphosis-based elemental composition. Our results show that the calcium and magnesium were found in a relatively high concentration, while the iron and zinc may be essential elements during the metamorphosis. Our results also show that in insect, the concentration of sodium was higher than in the pupa which may cause by hemolymph. We also demonstrated that the metamorphosis has an effect on the concentration of elements. Our study shows that in the different stages of insects, there are significant changes in the elemental composition of different stages of insects during their metamorphosis.

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“…In the larval beetle Tenebrio molitor , for example, the central complex comprises basic arrangements of decussating pioneer axons intersected by tangential processes, typifying the ground pattern organization of these centers. During larval maturation and metamorphosis to adulthood, the central complex acquires greater intricacy as more types of nerve cells contribute to it [Wegerhoff and Breidbach, 1992]. As does an adult insect, its larva will select actions appropriate to its ecology.…”

Section: Is Convergence a Useful Explanation For The Evolution Of Bramentioning

confidence: 99%

Homology versus Convergence in Resolving Transphyletic Correspondences of Brain Organization

Strausfeld

Hirth

2013

Brain Behav Evol

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Due to the largely absent fossil record, phylogenetic comparisons of brain structures rely on the analysis of nervous systems in extant taxa, many of which appear to have distinctive and dissimilar neural arrangements. The use of a multitude of comparative criteria, including developmental genetics, phylogenomics and neural circuit architecture, has recently resolved a highly conserved structural and functional ground pattern organization in the arthropod central complex and vertebrate basal ganglia. The minuteness of resemblance is exemplified by orthologous action selection circuits that are formed by homologous gene networks and which can lead to similar pathologies and behavioral disorders. It has been argued, however, that these similarities of brain centers can only be due to convergent evolution. What is still missing is a plausible scenario to explain how convergence could result in such a multitude of similarities and minuteness of resemblances, including gene expression, functional attributes and pathologies. In contrast, homology by common descent is the more parsimonious explanation. Moreover, the divergent elaboration of arthropod central complex and vertebrate basal ganglia does not obscure their shared ground pattern organization and thus genealogical correspondence.

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Structure and development of the larval central complex in a holometabolous insect, the beetle Tenebrio molitor

Cited by 70 publications

References 43 publications

Isolation and identification of a diuretic hormone from the mealworm Tenebrio molitor.

Isolation and identification of a diuretic hormone from the mealworm Tenebrio molitor.

Elemental Concentration in Mealworm Beetle (Tenebrio molitor L.) During Metamorphosis

Homology versus Convergence in Resolving Transphyletic Correspondences of Brain Organization

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