Quantification of gait parameters in freely walking wild type and sensory deprived Drosophila melanogaster

Coordinated walking in vertebrates and multi-legged invertebrates such as Drosophila melanogaster requires a complex neural network coupled to sensory feedback. An understanding of this network will benefit from systems such as Drosophila that have the ability to genetically manipulate neural activities. However, the fly's small size makes it challenging to analyze walking in this system. In order to overcome this limitation, we developed an optical method coupled with high-speed imaging that allows the tracking and quantification of gait parameters in freely walking flies with high temporal and spatial resolution. Using this method, we present a comprehensive description of many locomotion parameters, such as gait, tarsal positioning, and intersegmental and left-right coordination for wild type fruit flies. Surprisingly, we find that inactivation of sensory neurons in the fly's legs, to block proprioceptive feedback, led to deficient step precision, but interleg coordination and the ability to execute a tripod gait were unaffected. - See more at: http://elife.elifesciences.org/content/2/e00231#sthash.6OwrygKl.dpu

GLP-1 receptor stimulation of the lateral parabrachial nucleus reduces food intake: neuroanatomical, electrophysiological, and behavioral evidence.

The parabrachial nucleus (PBN) is a key nucleus for the regulation of feeding behavior. Inhibitory inputs from the hypothalamus to the PBN play a crucial role in the normal maintenance of feeding behavior, because their loss leads to starvation. Viscerosensory stimuli result in neuronal activation of the PBN. However, the origin and neurochemical identity of the excitatory neuronal input to the PBN remain largely unexplored. Here, we hypothesize that hindbrain glucagon-like peptide 1 (GLP-1) neurons provide excitatory inputs to the PBN, activation of which may lead to a reduction in feeding behavior. Our data, obtained from mice expressing the yellow fluorescent protein in GLP-1-producing neurons, revealed that hindbrain GLP-1-producing neurons project to the lateral PBN (lPBN). Stimulation of lPBN GLP-1 receptors (GLP-1Rs) reduced the intake of chow and palatable food and decreased body weight in rats. It also activated lPBN neurons, reflected by an increase in the number of c-Fos-positive cells in this region. Further support for an excitatory role of GLP-1 in the PBN is provided by electrophysiological studies showing a remarkable increase in firing of lPBN neurons after Exendin-4 application. We show that within the PBN, GLP-1R activation increased gene expression of 2 energy balance regulating peptides, calcitonin gene-related peptide (CGRP) and IL-6. Moreover, nearly 70% of the lPBN GLP-1 fibers innervated lPBN CGRP neurons. Direct intra-lPBN CGRP application resulted in anorexia. Collectively, our molecular, anatomical, electrophysiological, pharmacological, and behavioral data provide evidence for a functional role of the GLP-1R for feeding control in the PBN

Kinematic Responses to Changes in Walking Orientation and Gravitational Load in Drosophila melanogaster

Walking behavior is context-dependent, resulting from the integration of internal and external influences by specialized motor and pre-motor centers. Neuronal programs must be sufficiently flexible to the locomotive challenges inherent in different environments. Although insect studies have contributed substantially to the identification of the components and rules that determine locomotion, we still lack an understanding of how multi-jointed walking insects respond to changes in walking orientation and direction and strength of the gravitational force. In order to answer these questions we measured with high temporal and spatial resolution the kinematic properties of untethered Drosophila during inverted and vertical walking. In addition, we also examined the kinematic responses to increases in gravitational load. We find that animals are capable of shifting their step, spatial and inter-leg parameters in order to cope with more challenging walking conditions. For example, flies walking in an inverted orientation decreased the duration of their swing phase leading to increased contact with the substrate and, as a result, greater stability. We also find that when flies carry additional weight, thereby increasing their gravitational load, some changes in step parameters vary over time, providing evidence for adaptation. However, above a threshold that is between 1 and 2 times their body weight flies display locomotion parameters that suggest they are no longer capable of walking in a coordinated manner. Finally, we find that functional chordotonal organs are required for flies to cope with additional weight, as animals deficient in these proprioceptors display increased sensitivity to load bearing as well as other locomotive defects

Evaluation of three types of barriers to trap winter moth (Lepidoptera: Geometridae) adults

Three types of barrier traps, Tanglefoot®, fiberglass and fiberglass sprayed with the insecticide Raid®, were tested at three locations, on eight trees each per treatment and location for a total of 72 trees, to determine their efficiency in preventing the flightless winter moth females from crawling higher up the tree to oviposit. The efficiency of the barrier was evaluated by counting the number of female winter moth adults caught 10-15 cm above the test barrier. Tanglefoot® was the most effective barrier. An average of 67.1 winter moth females managed to crawl over the fiberglass barrier compared to 3.6 females over the fiberglass barrier sprayed with Raid® and 1.1 females over the Tanglefoot® barrier. The differences among the average catches were significant (P<0.01) for the fiberglass barrier but not between the fiberglass barrier with Raid® and the Tanglefoot® barrier. We recommend that Tanglefoot® applied over a polyethylene strip, after the bark crevices have been plugged, be used to prevent winter moth females from crawling under the barrier. The Tanglefoot® barrier has the added advantages that it is cheap, non-toxic and, since it reduces or eliminates the need for insecticide application, it is fully compatible with biological control measures

A globális éghajlatváltozás várható hatásai a növényvédelemben

A légköri CO2 koncentráció és az egyéb üvegházhatásért felelős gázok koncentrációjának növekedése miatt a Föld éghajlata melegszik és a klíma változik. Összeállításban a legfontosabb üvegházhatást kiváltó tényezők általános hatásait vizsgáljuk a növénypatogén mikroorganizmusokra, kártevő rovarokra és a gyomnövényekre, bemutatják a növény természetes ellenálló képességének útjait az abiotikus stressz-hatásokkal szemben. A megemelkedett CO2 koncentráció és a globális hőmérséklet-növekedés megváltoztatja a károsítók viselkedését, egyrészt, mert a megváltozott légköri CO2 tartalom miatt megváltozik fejlődési sebességük és a kiváltott tünetek ill. károk mértéke. Másrészt a megváltozott körülmények miatt megváltoznak maguk a növények is, amelyek ugyancsak változtatják a kórokozók fertőzési jellemzőit, a rovarok fejlődését is. Az előbb említett két fő tényező károsítókra gyakorolt hatása szerteágazó, egyes esetekben stimuláló, más esetekben gátló hatásokra kell számítanunk. Emiatt a hatások eredőjét nehéz tudományosan is megalapozott módon megjósolni. Mindehhez hozzá kell tenni azt is, hogy az éghajlatváltozás a mezőgazdasági régiók eltolódását is maga után vonhatja, és ez kiváltja a termesztett növények és azok károsítóinak változását is. Ennek következménye lehet az is, hogy az új területen megjelenő növénybetegségek és állati kártevők azokat a természetes növényi társulásokat is megváltoztathatják, amelyek azelőtt nem voltak kitéve a kultúrnövényeket károsító – számos esetben sokkal agresszívebb – fajoknak vagy változatoknak

Polyelectrolyte/surfactant films: from 2D to 3D structural control

Reversible control of the 3D structure of polyelectrolyte/surfactant films at the air/water interface is showcased. A recently discovered mechanism is exploited to form highly efficient, stable and biocompatible films by spreading aggregates composed of poly-L-lysine and sodium dodecyl sulfate on the surface of water. Reversible control of: (1) the surface monolayer coverage, (2) the switching on or off discrete extended structures, and (3) the extended structure coverage is demonstrated for the first time. The intricacy by which the film structures can be controlled is unprecedented and opens exciting potential to optimize film properties by chemical design for novel biomedical transfer applications.We thank the Institut Laue-Langevin for beam time on FIGARO (DOIs: https://doi.org/10.5291/ILL-DATA.9-12-614 and https://doi.org/10.5291/ILL-DATA.9-12-631), Simon Wood for technical assistance and the Partnership for Soft Condensed Matter (PSCM) for lab support. IV acknowledges the financial support from the Hungarian National Research, Development and Innovation Office (NKFIH K116629). AM acknowledges the financial support from MICINN under grant PID2021-129054NA-I00 and the IKUR Strategy of the Basque Government.Peer reviewe

AFM monitoring of the cut surface of a segmented polyurethane unveils a microtome-engraving induced growth process of oriented hard domains

We report on nanoscale order-disorder transitions of hard segments and their domains composed of 4,4′-methylenebis(phenyl isocyanate) - 1,4-butanediol (MDI-BD), in polycaprolactone-based (Mn = 2000 g/mol) polyurethanes (PCL-PUs), when the free surface is pre-oriented by cryo-microtoming of the material. Morphological variations of the hard domains as a function of temperature and the anisotropy of surface morphology features are captured by employing Atomic Force Microscopy (AFM) stiffness imaging by PeakForce Quantitative Nanomechanical Mapping (PF-QNM). The AFM imaging is supported by WAXS, SAXS, FTIR, and DSC measurements. The experimental results show that hard domains initially grown at the surface break apart at elevated temperatures (65 °C) and cannot be re-grown upon cooling. They require new microtoming to repeat the growth scenario. The detailed step-by-step submicron scale observations of the surfaces serve to show importance of the influence that microtoming and the time after its completion have on surface morphology, and that these shall be considered when studying polymer materials microscopically.</p

Hierarchical Black Hole Mergers in Active Galactic Nuclei

The origins of the stellar-mass black hole mergers discovered by LIGO/Virgo are still unknown. Here we show that, if migration traps develop in the \add{accretion} disks of Active Galactic Nuclei (AGNs) and promote the mergers of their captive black holes, the majority of black holes within disks will undergo hierarchical mergers---with one of the black holes being the remnant of a previous merger. 40% of AGN-assisted mergers detected by LIGO/Virgo will include a black hole with mass $\gtrsim 50$ M$_\odot$, the mass limit from stellar core collapse. Hierarchical mergers at traps in AGNs will exhibit black hole spins (anti-)aligned with the binary's orbital axis, a distinct property from other hierarchical channels. Our results are suggestive, although not definitive (with Odds ratio of $\sim 1$), that LIGO's heaviest merger so far, GW170729, could have originated from this channel.Comment: 6 pages, 3 figures; accepted in PR