A New Role for Neuropeptide F Signaling in Controlling Developmental Timing and Body Size in .

As juvenile animals grow, their behavior, physiology, and development need to be matched to environmental conditions to ensure they survive to adulthood. However, we know little about how behavior and physiology are integrated with development to achieve this outcome. Neuropeptides are prime candidates for achieving this due to their well-known signaling functions in controlling many aspects of behavior, physiology, and development in response to environmental cues.

Synchrotron radiation from an accelerating light pulse.

Synchrotron radiation-namely, electromagnetic radiation produced by charges moving in a curved path-is regularly generated at large-scale facilities where giga-electron volt electrons move along kilometer-long circular paths. We use a metasurface to bend light and demonstrate synchrotron radiation produced by a subpicosecond pulse, which moves along a circular arc of radius 100 micrometers inside a nonlinear crystal. The emitted radiation, in the terahertz frequency range, results from the nonlinear polarization induced by the pulse.

Torso-Like Is a Component of the Hemolymph and Regulates the Insulin Signaling Pathway in .

In , key developmental transitions are governed by the steroid hormone ecdysone. A number of neuropeptide-activated signaling pathways control ecdysone production in response to environmental signals, including the insulin signaling pathway, which regulates ecdysone production in response to nutrition. Here, we find that the Membrane Attack Complex/Perforin-like protein Torso-like, best characterized for its role in activating the Torso receptor tyrosine kinase in early embryo patterning, also regulates the insulin signaling pathway in We previously reported that the small body size and developmental delay phenotypes of null mutants resemble those observed when insulin signaling is reduced.

Genome-Wide Screen for New Components of the Torso Receptor Tyrosine Kinase Pathway.

Patterning of the embryonic termini by the Torso (Tor) receptor pathway has long served as a valuable paradigm for understanding how receptor tyrosine kinase signaling is controlled. However, the mechanisms that underpin the control of Tor signaling remain to be fully understood. In particular, it is unclear how the Perforin-like protein Torso-like (Tsl) localizes Tor activity to the embryonic termini.

MACPF/CDC proteins in development: Insights from Drosophila torso-like.

The Membrane Attack Complex Perforin-like/Cholesterol-Dependent Cytolysin (MACPF) superfamily is an ancient and biologically diverse group of proteins that are best known for pore-forming roles in mammalian immunity and bacterial pathogenesis. Intriguingly, however, some eukaryotic proteins which contain the MACPF domain that defines this family do not act in attack or defence, and instead have distinct developmental functions. It remains unclear whether these proteins function via pore formation or have a different mechanism of action.

Torso-like mediates extracellular accumulation of Furin-cleaved Trunk to pattern the Drosophila embryo termini.

Patterning of the Drosophila embryonic termini is achieved by localized activation of the Torso receptor by the growth factor Trunk. Governing this event is the perforin-like protein Torso-like, which is localized to the extracellular space at the embryo poles and has long been proposed to control localized proteolytic activation of Trunk. However, a protease involved in terminal patterning remains to be identified, and the role of Torso-like remains unknown.

Observation of standing waves of electron-hole sound in a photoexcited semiconductor.

Three-dimensional multicomponent plasmas composed of species with very different masses support a new branch of charge-density fluctuations known as acoustic plasmons. Here, we report on an ultrafast optical method to generate and probe coherent states of acoustic plasmons in a slab of GaAs, which relies on strong photoexcitation to create a large population of light electrons and heavy holes. Consistent with the random-phase-approximation theory, the data reveal standing plasma waves confined to these slabs, similar to those of conventional sound but with associated velocities that are significantly larger.

Trunk cleavage is essential for Drosophila terminal patterning and can occur independently of Torso-like.

Terminal patterning in Drosophila is governed by a localized interaction between the Torso kinase (Tor) and its ligand Trunk (Trk). Currently, it is proposed that Trk must be cleaved in order to bind Tor, and that these proteolytic events are controlled by secretion of Torso-like (Tsl) only at the embryo poles. However, controversy surrounds these ideas since neither cleaved Trk nor a protease that functions in terminal patterning have been identified.

Torso-like functions independently of Torso to regulate Drosophila growth and developmental timing.

Activation of the Drosophila receptor tyrosine kinase Torso (Tor) only at the termini of the embryo is achieved by the localized expression of the maternal gene Torso-like (Tsl). Tor has a second function in the prothoracic gland as the receptor for prothoracicotropic hormone (PTTH) that initiates metamorphosis. Consistent with the function of Tor in this tissue, Tsl also localizes to the prothoracic gland and influences developmental timing.

Glassy carbon tubular electrodes for the reduction of oxygen to hydrogen peroxide.

The oxygen reduction reaction (ORR) to produce hydrogen peroxide (H2O2) is of great industrial interest. Herein, a hydrodynamic electrochemical method is explored for use as a continuous method to produce H2O2 at the point-of-use. The ORR was studied in a tubular glassy carbon flow cell under a laminar flow regime.

Asymmetric Marcus-Hush theory for voltammetry.

The current state-of-the-art in modeling the rate of electron transfer between an electroactive species and an electrode is reviewed. Experimental studies show that neither the ubiquitous Butler-Volmer model nor the more modern symmetric Marcus-Hush model are able to satisfactorily reproduce the experimental voltammetry for both solution-phase and surface-bound redox couples. These experimental deviations indicate the need for revision of the simplifying approximations used in the above models.

Ammonium-directed olefinic epoxidation: kinetic and mechanistic insights.

The ammonium-directed olefinic epoxidations of a range of differentially N-substituted cyclic allylic and homoallylic amines (derived from cyclopentene, cyclohexene, and cycloheptene) have been investigated, and the reaction kinetics have been analyzed. The results of these studies suggest that both the ring size and the identity of the substituents on nitrogen are important in determining both the overall rate and the stereochemical outcome of the epoxidation reaction. In general, secondary amines or tertiary amines with nonsterically demanding substituents on nitrogen are superior to tertiary amines with sterically demanding substituents on nitrogen in their ability to promote the oxidation reaction.

Electrode kinetics at carbon electrodes and the density of electronic states.

Marcus-Hush theory relates the rate of electron transfer to the density of electronic states of the electrode material. Through use of a carbon microelectrode--for which the density of states is expected to vary as a function of potential--this predication is validated for graphitic materials by measurement of a variety of outer-sphere redox systems.

Mass transport to micro- and nanoelectrodes and their arrays: a review.

The use of micro- and nanoelectrodes and their arrays has become commonplace in modern electrochemistry. Numerical simulation is often required for detailed analysis of voltammetric data and this relies upon an understanding of the prevailing mass transport operating under the experimental conditions. The theoretical basis of our understanding of mass transport, particularly diffusion and migration, has developed greatly in recent years.

Edge plane pyrolytic graphite electrode covalently modified with 2-anthraquinonyl groups: theory and experiment.

An edge plane pyrolitic graphite (EPPG) electrode was modified by electrochemical reduction of anthraquinone-2-diazonium tetrafluoroborate (AQ2-N(2)(+)BF(4)(-)), giving an EPPG-AQ2-modified electrode of a surface coverage below a monolayer. Cyclic voltammograms simulated using Marcus-Hush theory for 2e(-) process assuming a uniform surface gave unrealistically low values of reorganisation energies, λ, for both electron transfer steps. Subsequently, two models of surface inhomogeneity based on Marcus-Hush theory were investigated: a distribution of formal potentials, E', and a distribution of electron tunneling distances, r(0).

Generator-collector experiments at a single electrode: exploring the general applicability of this approach by comparing the performance of surface immobilized versus solution phase sensing molecules.

We demonstrate proof-of-concept that generator-collector experiments can be performed at a single macroelectrode and used to determine mechanistic information. The practical advantages of such a system over conventional generator-collector techniques are also outlined. The single-electrode generator-collector technique is applied to study the known mechanism of oxygen reduction in aqueous conditions as a model system.