102 research outputs found
Neurons against Noise : Neural adaptations for dim light vision in hawkmoths
All animals perceive the world through their senses, which form the basis for their decisions and motor actions. However, when these all-important senses reach their limit and cease to provide reliable information, the animal’s survival is threatened. Among the senses, vision is brought to its limits on a daily basis, because its signal strength is diminished as night falls, and increases again as the sun rises. In this thesis, I investigated adaptations that enable the visual system of hawkmoths, a group of insects, to cope with the low light intensities they face at night. I have focused on neural adaptations, manifested in the processing of visual neurons, in contrast to anatomical adaptations, such as modifications of the eye. I showed that neural adaptations exist in the motion vision system of hawkmoths, in the form of integration of visual information in space and time. Furthermore, I demonstrated that a combination of such spatial and temporal summation increased sensitivity and information content in dim light (Paper I). The amount of spatial and temporal summation matched the ecological needs of different hawkmoth species, as well as their anatomical adaptations for visual sensitivity: night active species, and species with less sensitive eyes had more extensive spatial and temporal summation than day-active species and species with very sensitive optics (Paper II). Furthermore, I identified and characterised candidate neurons that carry out spatial and temporal summation in the brain of hawkmoths (Paper III). Finally, I quantified the effects of temporal summation on the ability of hawkmoths to track flowers in hovering flight at different light levels, and showed that a subset of the observed behavioural phenomena could be explained by temporal processing in the nervous system (Paper IV). Taken together, this work has provided detailed insight into how neural processing can increase visual reliability in dim light. The results presented are not only relevant to hawkmoths, since neural summation is also expected to increase visual sensitivity in other species of nocturnal insects, and can be compared to similar mechanisms in vertebrates. Furthermore, this work is instructive for the development of artificial visual systems, for which insect brains have proven to be a successful biomimetic model
Detection of Lipid Domains in Model and Plasma Membranes by Fluorescence Lifetime Imaging Microscopy of Fluorescent Lipid Analogues
Setting the Pace: New Insights into Central Pattern Generator Interactions in Box Jellyfish Swimming
Central Pattern Generators (CPGs) produce rhythmic behaviour across all animal phyla. Cnidarians, which have a radially symmetric nervous system and pacemaker centres in multiples of four, provide an interesting comparison to bilaterian animals for studying the coordination between CPGs. The box jellyfish Tripedalia cystophora is remarkable among cnidarians due to its most elaborate visual system. Together with their ability to actively swim and steer, they use their visual system for multiple types of behaviour. The four swim CPGs are directly regulated by visual input. In this study, we addressed the question of how the four pacemaker centres of this radial symmetric cnidarian interact. We based our investigation on high speed camera observations of the timing of swim pulses of tethered animals (Tripedalia cystophora) with one or four rhopalia, under different simple light regimes. Additionally, we developed a numerical model of pacemaker interactions based on the inter pulse interval distribution of animals with one rhopalium. We showed that the model with fully resetting coupling and hyperpolarization of the pacemaker potential below baseline fitted the experimental data best. Moreover, the model of four swim pacemakers alone underscored the proportion of long inter pulse intervals (IPIs) considerably. Both in terms of the long IPIs as well as the overall swim pulse distribution, the simulation of two CPGs provided a better fit than that of four. We therefore suggest additional sources of pacemaker control than just visual input. We provide guidelines for future research on the physiological linkage of the cubozoan CPGs and show the insight from bilaterian CPG research, which show that pacemakers have to be studied in their bodily and nervous environment to capture all their functional features, are also manifest in cnidarians
Correction: Expert Opinions on Improving Femicide Data Collection across Europe: A Concept Mapping Study
The eighth author’s name is spelled incorrectly. The correct name is Heidi Stöckl. There is an error in the fourth sentence of the penultimate paragraph in the Discussion section. The correct sentence is: Femicide was, for a long time, only addressed in Europe under the wider umbrella of violence against women. It gained greater research and public attention by European and global projects and institutions only in the last decade, under the COST Action IS1206 on Femicide, the EU Daphne Justice Programmes and addressed through ACUNS (Academic Council on the United Nations System) [44]. This updated sentence cites a new reference, which is: Weil, S. “Femicide in Europe”. In: Dimitrijevic, M., Filip, A and Platzer M (eds) Femicide: a Global Issue that Demands Action. Taking Action against Gender-Related Killing of Women and Girls, Vol. 4. Vienna: ACUNS; 2015. Pp.118-121
Phenolic Compounds of Red Wine \u3ci\u3eAglianico del Vulture\u3c/i\u3e Modulate the Functional Activity of Macrophages via Inhibition of \u3ci\u3eNF-κB\u3c/i\u3e and the Citrate Pathway
Phenolic compounds of red wine powder (RWP) extracted from the Italian red wine Aglianico del Vulture have been investigated for the potential immunomodulatory and anti-inflammatory capacity on human macrophages. These compounds reduce the secretion of IL-1β, IL-6, and TNF-α proinflammatory cytokines and increase the release of IL-10 anti-inflammatory cytokine induced by lipopolysaccharide (LPS). In addition, RWP restores Annexin A1 levels, thus involving activation of proresolutive pathways. Noteworthy, RWP lowers NF-κB protein levels, promoter activity, and nuclear translocation. As a consequence of NF-κB inhibition, reduced promoter activities of SLC25A1—encoding the mitochondrial citrate carrier (CIC)—and ATP citrate lyase (ACLY) metabolic genes have been observed. CIC, ACLY, and citrate are components of the citrate pathway: in LPS-activated macrophages, the mitochondrial citrate is exported by CIC into the cytosol where it is cleaved by ACLY in oxaloacetate and acetyl-CoA, precursors for ROS, NO⋅, and PGE2 inflammatory mediators. We identify the citrate pathway as a RWP target in carrying out its anti-inflammatory activity since RWP reduces CIC and ACLY protein levels, ACLY enzymatic activity, the cytosolic citrate concentration, and in turn ROS, NO⋅, PGE2, and histone acetylation levels. Overall findings suggest that RWP potentially restores macrophage homeostasis by suppressing inflammatory pathways and activating proresolutive processes
Issues in measuring and comparing the incidence of intimate partner homicide and femicide - A focus on Europe
Intimate partner homicide is an important contributor to homicide rates worldwide, disproportionally affecting women as victims. Still, major gaps exist in the measurement of intimate partner homicide, with many homicides not being identified as intimate partner homicides. This article provides an overview of the main issues in the collection and reporting on intimate partner homicide, focusing in particular on the data situation in Europe. Sources of homicide data - national and police statistics, court statistics and files, mortuary data and newspaper databases - face similar challenges, namely absence or missing information on the victim-offender relationship, and different categorizations of key parameters, such as definition of intimate partner homicide, and identification of reporting periods. This is concerning, as strong and reliable data on the incidence and contextual information of intimate partner homicide and femicide is important to advice effective prevention strategies
Women's understanding of economic abuse in North-Western Tanzania.
INTRODUCTION: Economic abuse is a form of intimate partner violence that still lacks a clear conceptualization and therefore is often overlooked next to physical, sexual and psychological abuse. While existing categorizations recognize economic intimate partner violence as economic control, economic exploitation and employment sabotage, current measurements of economic abuse rarely capture all its forms, and the issue has not been widely explored in low- and middle-income country settings. METHODS: We conducted in-depth interviews with 18 women in Mwanza, Tanzania to understand local perceptions and experiences of economic intimate partner violence. We used a thematic analysis approach. RESULTS: Our study illustrates the complexity of economic abuse as a unique form of intimate partner violence, with women experiencing economic exploitation, employment sabotage, economic control and male economic irresponsibility. Gender norms and expectations actively played a key role in furthering abusive economic behaviour as women attempted to generate their own income and participate in financial decisions. Women's constructs and reactions to economic abuse diverged sharply from the traditional marital expectations of dutifully accepting male control and the men being the main breadwinners in the family. Despite it being widespread, women did not find economic abuse acceptable. CONCLUSION: The results highlight that economic abuse is a complex issue and that more research on the pathways and manifestations of economic abuse globally would be beneficial. Existing measurement tools should be widened to address all dimensions of economic abuse. Addressing economic abuse will require multi-strategy interventions, working at the individual and community-level to address gender roles and masculinity norms, working with both men and women
Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.
Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
The role of ocelli in cockroach optomotor performance
Insect ocelli are relatively simple eyes that have been assigned various functions not related to pictorial vision. In some
species they function as sensors of ambient light intensity, from which information is relayed to various parts of the nervous
system, e.g., for the control of circadian rhythms. In this work we have investigated the possibility that the ocellar light
stimulation changes the properties of the optomotor performance of the cockroach Periplaneta americana. We used a virtual
reality environment where a panoramic moving image is presented to the cockroach while its movements are recorded with
a trackball. Previously we have shown that the optomotor reaction of the cockroach persists down to the intensity of moonless
night sky, equivalent to less than 0.1 photons/s being absorbed by each compound eye photoreceptor. By occluding the
compound eyes, the ocelli, or both, we show that the ocellar stimulation can change the intensity dependence of the optomotor
reaction, indicating involvement of the ocellar visual system in the information processing of movement. We also measured
the cuticular transmission, which, although relatively large, is unlikely to contribute profoundly to ocellar function, but may
be significant in determining the mean activity level of completely blinded cockroaches
A Systematic Proteomic Study of Irradiated DNA Repair Deficient Nbn-Mice
BACKGROUND: The NBN gene codes for the protein nibrin, which is involved in the detection and repair of DNA double strand breaks (DSBs). The NBN gene is essential in mammals. METHODOLOGY/PRINCIPAL FINDINGS: We have used a conditional null mutant mouse model in a proteomics approach to identify proteins with modified expression levels after 4 Gy ionizing irradiation in the absence of nibrin in vivo. Altogether, amongst approximately 8,000 resolved proteins, 209 were differentially expressed in homozygous null mutant mice in comparison to control animals. One group of proteins significantly altered in null mutant mice were those involved in oxidative stress and cellular redox homeostasis (p<0.0001). In substantiation of this finding, analysis of Nbn null mutant fibroblasts indicated an increased production of reactive oxygen species following induction of DSBs. CONCLUSIONS/SIGNIFICANCE: In humans, biallelic hypomorphic mutations in NBN lead to Nijmegen breakage syndrome (NBS), an autosomal recessive genetic disease characterised by extreme radiosensitivity coupled with growth retardation, immunoinsufficiency and a very high risk of malignancy. This particularly high cancer risk in NBS may be attributable to the compound effect of a DSB repair defect and oxidative stress
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