1,721,083 research outputs found
Histones, Their Variants and Post-translational Modifications in Zebrafish Development
Full text linkComplex multi-cellular organisms are shaped starting from a single-celled zygote, owing to elaborate developmental programs. These programs involve several layers of regulation to orchestrate the establishment of progressively diverging cell type-specific gene expression patterns. In this scenario, epigenetic modifications of chromatin are central in influencing spatiotemporal patterns of gene transcription. In fact, it is generally recognized that epigenetic changes of chromatin states impact on the accessibility of genomic DNA to regulatory proteins. Several lines of evidence highlighted that zebrafish is an excellent vertebrate model for research purposes in the field of developmental epigenetics. In this review, I focus on the dynamic roles recently emerged for histone post-translational modifications (PTMs), histone modifying enzymes, histone variants and histone themselves in the coordination between the precise execution of transcriptional programs and developmental progression in zebrafish. In particular, I first outline a synopsis of the current state of knowledge in this field during early embryogenesis. Then, I present a survey of histone-based epigenetic mechanisms occurring throughout morphogenesis, with a stronger emphasis on cardiac formation. Undoubtedly, the issues addressed in this review take on particular importance in the emerging field of comparative biology of epigenetics, as well as in translational research
The expanding constellation of histone post-translational modifications in the epigenetic landscape
Full text linkThe emergence of a nucleosome-based chromatin structure accompanied the evolutionary transition from prokaryotes to eukaryotes. In this scenario, histones became the heart of the complex and precisely timed coordination between chromatin architecture and functions during adaptive responses to environmental influence by means of epigenetic mechanisms. Notably, such an epigenetic machinery involves an overwhelming number of post-translational modifications at multiple residues of core and linker histones. This review aims to comprehensively describe old and recent evidence in this exciting field of research. In particular, histone post-translational modification establishing/removal mechanisms, their genomic locations and implication in nucleosome dynamics and chromatin-based processes, as well as their harmonious combination and interdependence will be discussed
Epigenetic Modulation of Chromatin States and Gene Expression by G-Quadruplex Structures
Full text linkG-quadruplexes are four-stranded helical nucleic acid structures formed by guanine-rich sequences. A considerable number of studies have revealed that these noncanonical structural motifs are widespread throughout the genome and transcriptome of numerous organisms, including humans. In particular, G-quadruplexes occupy strategic locations in genomic DNA and both coding and noncoding RNA molecules, being involved in many essential cellular and organismal functions. In this review, we first outline the fundamental structural features of G-quadruplexes and then focus on the concept that these DNA and RNA structures convey a distinctive layer of epigenetic information that is critical for the complex regulation, either positive or negative, of biological activities in different contexts. In this framework, we summarize and discuss the proposed mechanisms underlying the functions of G-quadruplexes and their interacting factors. Furthermore, we give special emphasis to the interplay between G-quadruplex formation/disruption and other epigenetic marks, including biochemical modifications of DNA bases and histones, nucleosome positioning, and three-dimensional organization of chromatin. Finally, epigenetic roles of RNA G-quadruplexes in post-transcriptional regulation of gene expression are also discussed. Undoubtedly, the issues addressed in this review take on particular importance in the field of comparative epigenetics, as well as in translational research
Roles of the Core Components of the Mammalian miRISC in Chromatin Biology
Full text linkThe Argonaute (AGO) and the Trinucleotide Repeat Containing 6 (TNRC6) family proteins are the core components of the mammalian microRNA-induced silencing complex (miRISC), the machinery that mediates microRNA function in the cytoplasm. The cytoplasmic miRISC-mediated post-transcriptional gene repression has been established as the canonical mechanism through which AGO and TNRC6 proteins operate. However, growing evidence points towards an additional mechanism through which AGO and TNRC6 regulate gene expression in the nucleus. While several mechanisms through which miRISC components function in the nucleus have been described, in this review we aim to summarize the major findings that have shed light on the role of AGO and TNRC6 in mammalian chromatin biology and on the implications these novel mechanisms may have in our understanding of regulating gene expression
Design and Experimental Testing of a Droop Nose Morphing for Advanced Regional Aircraft
Full text linkMorphing wing structures can improve the aircraft performances thanks to the possibility to adapt the wing shape throughout the mission. In this paper, a multi-level multi-disciplinary optimization procedure has been applied to the design of a morphing Droop Nose device, in the framework of Clean Sky 2 REG-IADP AIR- GREEN 2 project. The procedure starts from the initial design requirements and achieves the design, manu¬facturing and testing of two experimental ground demonstrators for the assessment of the developed concept. The experimental tests enable the validation of the numerical results and demonstrate the effectiveness of the proposed morphing technology
Design and Testing of a Droop Nose Morphing for Advanced Regional Aircraft: Numerical and Experimental Validation
No full textMorphing wing devices can improve the aircraft performances thanks to the possibility to change the wing shape throughout the mission. Dedicated design procedures, based on optimization techniques, have been applied in several research projects to realize leading and trailing-edge devices able to enhance the high lift performances during take-off and landing phases. In the framework of Clean Sky 2 REG-IADP AIRGREEN 2 (AG2) project, the morphing Droop Nose has been one of the devices conceived for application on a regional transport aircraft. The numerical design has proven to be very promising, but the expected performances must be confirmed by a real demonstrator. This paper describe the design, manufacturing and testing of a full-scale prototype of the droop nose. The purpose of the activity is to demonstrate the benefits of morphing, experimentally validating the numerical results. The main concern of the work has been the achievement of a feasible solution based on the use of conventional aeronautical materials. The experimental tests have assessed the device functionality, demonstrated the structural feasibility and validated the achieved morphing shape. Moreover, the experimental activity has been fundamental to highlight critical aspects and to solve the issues related to the proposed technology, with particular attention to the manufacturing phase
Ritrovata cimice asiatica a Bari, le colture più a rischio
No full textDopo una prima segnalazione nel 2016 e una
successiva nel corso di quest’anno, nei giorni scorsi
è stata inviata una comunicazione all’Osservatorio
fitosanitario della Regione Puglia dopo il ritrovamento
di alcuni esemplari a diversi stadi biologici di H. halys,
o cimice asiatica. Pesco, ciliegio, albicocco, agrumi
e pomodoro potrebbero essere le colture più a rischi
Ritrovata cimice asiatica a Bari, le colture più a rischio
Full text linkNota sui primi rinvenimenti della cimice Asiatica Halyomorpha halys in Pugli
Evaluation of epigenetic and radiomodifying effects during radiotherapy treatments in zebrafish
Full text linkRadiotherapy is still a long way from personalizing cancer treatment plans, and its effective-ness depends on the radiosensitivity of tumor cells. Indeed, therapies that are efficient and successful for some patients may be relatively ineffective for others. Based on this, radiobiological research is focusing on the ability of some reagents to make cancer cells more responsive to ionizing radiation, as well as to protect the surrounding healthy tissues from possible side effects. In this scenario, zebrafish emerged as an effective model system to test for radiation modifiers that can potentially be used for radiotherapeutic purposes in humans. The adoption of this experimental organism is fully justified and supported by the high similarity between fish and humans in both their genome sequences and the effects provoked in them by ionizing radiation. This review aims to provide the literature state of the art of zebrafish in vivo model for radiobiological studies, particularly focusing on the epigenetic and radiomodifying effects produced during fish embryos’ and larvae’s exposure to radiotherapy treatments
Aero-Structural Design Optimization of a Morphing Aileron Considering Actuation Aspects
Full text linkThis paper summarizes the results obtained in the framework of the Clean Aviation Joint Undertaking on the development of a dedicated morphing aileron. This device, designed to be installed on the high aspect ratio wing of a hybrid–electric regional aircraft, is conceived to replace the traditional hinged aileron with an innovative aileron optimized for minimizing the actuation force and the aerodynamic drag, ensuring a smoothed and continuous skin surface. The design of such a complex device required a multi–disciplinary design approach, able to combine aerodynamic performances, kinematic and structural requirements, and actuation aspects related to the compliant structures concept on which the morphing device is based. The paper includes the description of the different design levels together with the obtained results, the selected optimal solutions, and finally a numerical validation phase
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