Epigenetics and locust life phase transitions.

Insects are one of the most successful classes on Earth, reflected in an enormous species richness and diversity. Arguably, this success is partly due to the high degree to which polyphenism, where one genotype gives rise to more than one phenotype, is exploited by many of its species. In social insects, for instance, larval diet influences the development into distinct castes; and locust polyphenism has tricked researchers for years into believing that the drastically different solitarious and gregarious phases might be different species.

Biofouling ecology as a means to better understand membrane biofouling.

Despite more than a decade of worldwide research on membrane fouling in membrane bioreactors, many questions remain to be answered. Biofouling, which is referred to as the unwanted deposition and growth of biofilms, remains the main problem. Due to its complexity, most of the existing anti-biofouling strategies are not completely successful.

The mode of action of juvenile hormone and ecdysone: towards an epi-endocrinological paradigm?

In some insect species, two sites of juvenile hormone (JH) synthesis have been reported: the very well documented corpora allata that secrete JH for "general use", and the reproductive system, in particular the male accessory glands, in which the function of the sometimes huge amounts of JH (e.g. in Hyalophora cecropia) remains to be clarified.

Characterization of genome methylation patterns in the desert locust Schistocerca gregaria.

DNA methylation is a widely conserved epigenetic modification. The analysis of genome-scale DNA methylation patterns in various organisms suggests that major features of animal methylomes are widely conserved. However, based on the variation of DNA methyltransferase genes in invertebrates, it has also been proposed that DNA methylation could provide a molecular mechanism for ecological adaptation.

The Fading Electricity Theory of Ageing: the missing biophysical principle?

Since a few years convincing data are accumulating showing that some of the premises of the master integrative theory of ageing, namely Harman's Reactive Oxygen Species or free radical theory, are less well founded than originally assumed. In addition, none of the about another dozen documented ageing mechanisms seems to hold the final answer as to the ultimate cause and evolutionary significance of ageing. This review raises the question whether, perhaps, something important has been overlooked, namely a biophysical principle, electrical in nature.

Worker honeybee sterility: a proteomic analysis of suppressed ovary activation.

Eusocial behavior is extensively studied in the honeybee, Apis mellifera, as it displays an extreme form of altruism. Honeybee workers are generally obligatory sterile in a bee colony headed by a queen, but the inhibition of ovary activation is lifted upon the absence of queen and larvae. Worker bees are then able to develop mature, viable eggs.

Phenotypic and genome-wide analysis of an antibiotic-resistant small colony variant (SCV) of Pseudomonas aeruginosa.

Background: Small colony variants (SCVs) are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch.

Methodology/principal Findings: One SCV (termed PAO-SCV) was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime.

Male reproduction is affected by RNA interference of period and timeless in the desert locust Schistocerca gregaria.

In all living organisms, behavior, metabolism and physiology are under the regulation of a circadian clock. The molecular machinery of this clock has been conserved throughout the animal kingdom. Besides regulating the circadian timing of a variety of processes through a central oscillating mechanism in the brain, these circadian clock genes were found to have a function in peripheral tissues in different insects.

Fruitless RNAi knockdown in the desert locust, Schistocerca gregaria, influences male fertility.

In Drosophila melanogaster, the male-specific splice isoform of the fruitless gene (Fru(M)) encodes a set of transcription factors that are involved in the regulation of male courtship and copulation. Recent insights from non-drosophilid insects suggest a conserved evolutionary role for the transcription factor Fruitless. In the desert locust, Schistocerca gregaria and the German cockroach, Blatella germanica, both orthopteran insects, a conserved functional role for fruitless has been proposed.

In search for non-steroidogenic functions of the prothoracic glands of the desert locust, Schistocerca gregaria: a peptidomic and proteomic approach.

The only well established function of the prothoracic glands (PGs) of insects is the production of ecdysteroids. In gregarious locusts, like in most insect species, the PGs degenerate soon after the adult molt. In this way they resemble the thymus of mammals, a gland with an important role in the build up of the immune system in young animals.

Differential proteomics in dequeened honeybee colonies reveals lower viral load in hemolymph of fertile worker bees.

The eusocial societies of honeybees, where the queen is the only fertile female among tens of thousands sterile worker bees, have intrigued scientists for centuries. The proximate factors, which cause the inhibition of worker bee ovaries, remain largely unknown; as are the factors which cause the activation of worker ovaries upon the loss of queen and brood in the colony. In an attempt to reveal key players in the regulatory network, we made a proteomic comparison of hemolymph profiles of workers with completely activated ovaries vs.

Locust phase polyphenism: Does epigenetic precede endocrine regulation?

The morphological, physiological and behavioural differences between solitarious and gregarious desert locusts are so pronounced that one could easily mistake the two phases as belonging to different species, if one has no knowledge of the phenomenon of phenotypic plasticity. A number of phase-specific features are hormonally controlled. Juvenile hormone promotes several solitarious features, the green cuticular colour being the most obvious one.

Fruitless RNAi knockdown in males interferes with copulation success in Schistocerca gregaria.

In Drosophila melanogaster, the male-specific splice isoform of the fruitless gene (Fru(M)) codes for a set of transcription factors that are involved in the regulation of male courtship and copulation. Fru(M) is expressed in an interconnected neuronal circuit containing central and sensory neurons as well as motor neurons. A partial sequence from the Schistocerca gregaria fru-gene from an EST database allowed quantitative real time analysis of fru-expression in adult locusts, and revealed the highest expression in the testes, accessory glands as well as the brain (and optic lobes).

The circadian clock genes affect reproductive capacity in the desert locust Schistocerca gregaria.

The circadian clocks govern many metabolic and behavioral processes in an organism. In insects, these clocks and their molecular machinery have been found to influence reproduction in many different ways. Reproductive behavior including courtship, copulation and egg deposition, is under strong influence of the daily rhythm.

Dispersion of peptides in vegetable oil as a simple slow release formula for both injection and oral uptake in insects: a case study with [His7]-corazonin in an albino Locusta migratoria deficient in corazonin.

Upon realizing that for drug delivery in the body, lipidization is a technique used in the pharmaceutical industry, we took in consideration that corazonin melanizes the cuticle of albino Locusta migratoria only when injected in an emulsion in oil, not when applied in a watery solution. In this study, we investigate the possibility for oral uptake of corazonin dispersed in oil, and validated the activity by a melanization assay. Not only was it active, it also induced red cuticular coloration in some animals, and it was also unexpectedly lethal for nymphs, but not for adults.

Sexual differentiation in adult insects: male-specific cuticular yellowing in Schistocerca gregaria as a model for reevaluating some current (neuro)endocrine concepts.

Changes in the color of the cuticle, days after the completion of hardening, are rare in adult insects. Even more so when such changes are specific to one sexual form and coincide with sexual maturation. Adult males of the desert locust Schistocerca gregaria deposit a well characterized 'yellow protein' in their cuticle about 10 days after the adult molt, but only if they live under crowded (gregarious) conditions.

A differential proteomics study of Caenorhabditis elegans infected with Aeromonas hydrophila.

The striking similarities between the innate defences of vertebrates and invertebrates as well as the amenability of Caenorhabditis elegans for genetic analysis, have made this free-living ground nematode a popular model system in the study of bacterial pathogenesis. Although genetic studies have brought new insights, showing the inducibility and pathogen-specificity of the immune response, there is still much to be discovered about the exact mechanisms underlying resistance to infection. In this paper a different angle was adopted to study host-pathogen interactions in C.

In search for a common denominator for the diverse functions of arthropod corazonin: a role in the physiology of stress?

Corazonin (Crz) is an 11 amino acid C-terminally amidated neuropeptide that has been identified in most arthropods examined with the notable exception of beetles and an aphid. The Crz-receptor shares sequence similarity to the GnRH-AKH receptor family thus suggesting an ancestral function related to the control of reproduction and metabolism. In 1989, Crz was purified and identified as a potent cardioaccelerating agent in cockroaches (hence the Crz name based on "corazon", the Spanish word for "heart").

Mass spectrometric profiling of (neuro)-peptides in the worker honeybee, Apis mellifera.

The honeybee is the economically most important beneficial insect and a model for studying immunity, development and social behavior. Hence, this species was selected for genome sequencing and annotation. An intensive interplay between bioinformatics and mass spectrometry (MS) resulted in the annotation of 36 neuropeptide genes (Hummon et al.