Fly neurons in culture: a model for neural development and pathology.

Primary neural cultures from the fruit fly, Drosophila melanogaster, enable a high-resolution glance into cellular processes and neuronal interaction. The development of the culture, along with its vitality and functionality, can be continuously monitored, and the abundance of available tools for D. melanogaster research can greatly assist in characterizing different aspects of the culture.

Emerging model systems in evo-devo: horned beetles and the origins of diversity.

Horned beetles and beetle horns are emerging as a model system suited to address fundamental questions in evolutionary developmental biology. Here we briefly review the biology of horned beetles and highlight the unusual opportunities they provide for evo-devo research. We then summarize recent advances in the development of new approaches and techniques that are now available to scientists interested in working with these organisms.

Discrete pulses of molting hormone, 20-hydroxyecdysone, during late larval development of Drosophila melanogaster: correlations with changes in gene activity.

Periodic pulses of the insect steroid molting hormone 20-hydroxyecdysone (20E), acting via its nuclear receptor complex (EcR/USP), control gene expression at many stages throughout Drosophila development. However, during the last larval instar of some lepidopteran insects, subtle changes in titers of ecdysteroids have been documented, including the so-called "commitment peak." This small elevation of 20E reprograms the larva for metamorphosis to the pupa.

Interaction between hormonal signaling pathways in Drosophila melanogaster as revealed by genetic interaction between methoprene-tolerant and broad-complex.

Juvenile hormone (JH) regulates insect development by a poorly understood mechanism. Application of JH agonist insecticides to Drosophila melanogaster during the ecdysone-driven onset of metamorphosis results in lethality and specific morphogenetic defects, some of which resemble those in mutants of the ecdysone-regulated Broad-Complex (BR-C). The Methoprene-tolerant (Met) bHLH-PAS gene mediates JH action, and Met mutations protect against the lethality and defects.

The physiology of locust phase polymorphism: an update.

The considerable progress made between 1990 and 1997 in locust phase-related research and in understanding the physiology of locust phase polymorphism is reviewed. The traits of locust phases are discussed and it is concluded that there are distinct strain-dependent differences in phase characteristics and their amplitudes even in the same species. Despite some advances, no major break-through was achieved in the putative endocrine control of locust phase polymorphism.

Nuclear magnetic resonance (NMR) studies of the dark-color-inducing neurohormone of locusts and corazonin.

The dark-color-inducing neurohormone (DCIN) of locusts and corazonin of a cockroach, both 11 residue-long peptides, induce dark coloration in albino nymphs of Locusta migratoria when injected after a nymphal molt. These peptides differ at position 7 (His in DCIN and Arg in corazonin) and elicit an almost identical darkening response. The three-dimensional structures of these peptides, dissolved in dimethylsulfoxide (DMSO), were determined by NMR.

Structure-activity relations of the dark-colour-inducing neurohormone of locusts.

The dark-colour-inducing effect of several peptides in comparison to that of the dark-colour-inducing neurohormone (DCIN, [His(7)]-corazonin) of locusts was investigated by a bioassay based on nymphs of a DCIN-deficient albino mutant of Locusta migratoria. The study was aimed at elucidating the active part of the DCIN and to explore the contribution of its amino acids to the activity. Graded doses of all peptides were injected in oil.