HDAC4 regulates satellite cell proliferation and differentiation by targeting P21 and Sharp1 genes

Skeletal muscle exhibits a high regenerative capacity, mainly due to the ability of satellite cells to replicate and differentiate in response to appropriate stimuli. Epigenetic control is effective at different stages of this process. It has been shown that the chromatin-remodeling factor HDAC4 is able to regulate satellite cell proliferation and commitment. However, its molecular targets are still uncovered. To explain the signaling pathways regulated by HDAC4 in satellite cells, we generated tamoxifen-inducible mice with conditional inactivation of HDAC4 in Pax7(+) cells (HDAC4 KO mice). We found that the proliferation and differentiation of HDAC4 KO satellite cells were compromised, although similar amounts of satellite cells were found in mice. Moreover, we found that the inhibition of HDAC4 in satellite cells was sufficient to block the differentiation process. By RNA-sequencing analysis we identified P21 and Sharp1 as HDAC4 target genes. Reducing the expression of these target genes in HDAC4 KO satellite cells, we also defined the molecular pathways regulated by HDAC4 in the epigenetic control of satellite cell expansion and fusion

Coordination networks incorporating halogen-bond donor sites and azobenzene groups

Two Zn coordination networks, {[Zn(1)(Py)(2)](2)(2-propanol)}(n) (3) and {[Zn(1)(2)(Bipy)(2)](DMF)(2)}(n) (4), incorporating halogen-bond (XB) donor sites and azobenzene groups have been synthesized and fully characterized. Obtaining 3 and 4 confirms that it is possible to use a ligand wherein its coordination bond acceptor sites and XB donor sites are on the same molecular scaffold (i.e., an aromatic ring) without interfering with each other. We demonstrate that XBs play a fundamental role in the architectures and properties of the obtained coordination networks. In 3, XBs promote the formation of 2D supramolecular layers, which, by overlapping each other, allow the incorporation of 2-propanol as a guest molecule. In 4, XBs support the connection of the layers and are essential to firmly pin DMF solvent molecules through I center dot center dot center dot O contacts, thus increasing the stability of the solvated systems

Surface-Relief Gratings in Halogen-Bonded Polymer–Azobenzene Complexes: A Concentration-Dependence Study

In recent years, supramolecular complexes comprising a poly(4-vinylpyridine) backbone and azobenzene-based halogen bond donors have emerged as a promising class of materials for the inscription of light-induced surface-relief gratings (SRGs). The studies up to date have focused on building supramolecular hierarchies, i.e., optimizing the polymer–azobenzene noncovalent interaction for efficient surface patterning. They have been conducted using systems with relatively low azobenzene content, and little is known about the concentration dependence of SRG formation in halogen-bonded polymer–azobenzene complexes. Herein, we bridge this gap, and study the concentration dependence of SRG formation using two halogen-bond-donating azobenzene derivatives, one functionalized with a tetrafluoroiodophenyl and the other with an iodoethynylphenyl group. Both have been previously identified as efficient molecules in driving the SRG formation. We cover a broad concentration range, starting from 10 mol % azobenzene content and going all the way up to equimolar degree of complexation. The complexes are studied as spin-coated thin films, and analyzed by optical microscopy, atomic force microscopy, and optical diffraction arising during the SRG formation. We obtained diffraction efficiencies as high as 35%, and modulation depths close to 400 nm, which are significantly higher than the values previously reported for halogen-bonded polymer–azobenzene complexes

Engineering efficient materials for optoelectronic applications through halogen bonding

I concetti della chimica supramolecolare sono utilizzati in questo lavoro per la progettazione e la sintesi di molecole e strutture supramolecolari efficienti per applicazioni di optoelettronica . Questo lavoro si differenzia dall' eccellente lavoro di Priimagi e Vaapavuori (vedi rif . 10 e 30 nell Introduzione), perché tutte le strutture supramolecolari qui presenti sono formate tramite un processo di auto-assemblaggio indotto dal legame ad alogeno. Il legame ad alogeno (XB) è un interazione non covalente direzionale e forte che condivide molte caratteristiche con il ben più noto legame ad idrogeno. In particolare, la direzionalità del legame ad alogeno è la forza motrice principale delle interessanti proprietà dei materiali qui riportati. Questa tesi si compone di cinque capitoli. Nell'introduzione vengono evidenziate le caratteristiche della chimica supramolecolare, dei materiali fotoattivi, e del legame ad alogeno. Nel secondo e nel terzo capitolo sono stati studiati i polimeri fotoattivi e i cristalli liquidi fotoattivi, rispettivamente. Nel caso dei polimeri è stato dimostrato che il legame ad alogeno è più affidabile del legame ad idrogeno nella promozione delle caratteristiche fotoresponsive. Nel caso dei cristalli liquidi è stato dimostrato che il legame ad alogeno è forte e direzionale abbastanza da promuovere un efficiente fotoallineamento e formazione di surface relief grating nello stesso complesso. Questi fenomeni di solito si verificano in molecole molto diverse. Nel quarto capitolo, sono state studiate supramolecole altamente fluorurate contenenti azobenzeni ed eterocicli. Lo studio del rapporto struttura-attività in queste strutture porterà nel prossimo futuro a risultati molto interessanti nel campo dei cristalli liquidi supramolecolari (nel caso degli eterocicli) o dei cristalli fotomobili (nel caso degli azobenzeni) . Il quinto capitolo è la parte sperimentale .The concepts of supramolecular chemistry are used throughout this work for the design and synthesis of efficient molecules and supramolecules for optoelectronics applications. This work differs from the excellent work of Priimagi and Vaapavuori (see ref. 10 and 30 in the Introduction) because all the structures present here are formed by a self-assembly process induced by halogen bonding. Halogen bonding (XB) is a high directional, strong and tunable non-covalent interaction that shares many features with the much better known hydrogen bonding. In particular the halogen bonding directionality is the main driving force of the interesting properties of the materials reported here. This thesis is composed of five chapters. In the introduction the features of supramolecular chemistry, photoactive materials, and halogen bonding are highlighted. In the second and the third chapter, were investigated photoactive polymers and liquid crystals, respectively. In the case of the polymers it is demonstrated that halogen bonding is more reliable than hydrogen bonding in promoting the photoreponsive behavior. In the case of the liquid crystals it is demonstrated that halogen bonding is strong and directional enough to promote efficient photoalignment and Surface Relief Grating formation in the same complex. These phenomena usually occur in very different molecular environments. In the fourth chapter, highly fluorinated azobenzene and heterocyclic supramolecules were studied. The investigation of the structure-function relationships in these structures will lead in the next future to very interesting supramolecular liquid crystals (in the case of the eterocycles) or photomoble crystals (in the case of the azobenzenes). The fifth chapter is the experimental part.DIPARTIMENTO DI CHIMICA, MATERIALI E INGEGNERIA CHIMICA GIULIO NATTA26RESNATI, GIUSEPPEFARAVELLI, TIZIAN

Halogen bonding enhances nonlinear optical response in poled supramolecular polymers

We demonstrate that halogen bonding strongly enhances the nonlinear optical response of poled supramolecular polymer systems. We compare three nonlinear optical chromophores with similar electronic structures but different bond-donating units, and show that both the type and the strength of the noncovalent interaction between the chromophores and the polymer matrix play their own distinctive roles in the optical nonlinearity of the systems

De Novo Assembly and Transcriptome Analysis of the Mediterranean Fruit Fly Ceratitis capitata Early Embryos

The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, belongs to the Tephritidae family, which includes a large number of other damaging pest species. The Medfly has been the first non-drosophilid fly species which has been genetically transformed paving the way for designing genetic-based pest control strategies. Furthermore, it is an experimentally tractable model, in which transient and transgene-mediated RNAi have been successfully used. We applied Illumina sequencing to total RNA preparations of 8-10 hours old embryos of C. capitata, This developmental window corresponds to the blastoderm cellularization stage. In summary, we assembled 42,614 transcripts which cluster in 26,319 unique transcripts of which 11,045 correspond to protein coding genes; we identified several hundreds of long ncRNAs; we found an enrichment of transcripts encoding RNA binding proteins among the highly expressed transcripts, such as CcTRA-2, known to be necessary to establish and, most likely, to maintain female sex of C. capitata. Our study is the first de novo assembly performed for Ceratitis capitata based on Illumina NGS technology during embryogenesis and it adds novel data to the previously published C. capitata EST databases. We expect that it will be useful for a variety of applications such as gene cloning and phylogenetic analyses, as well as to advance genetic research and biotechnological applications in the Medfly and other related Tephritidae

Halogen bond directionality translates tecton geometry into self-assembled architecture geometry

The structures of halogen-bonded infinite chains involving two diiodoperfluoroalkanes and a bent bis(pyrid-4′-yl)oxadiazole show that the geometry of the pyridyl pendant rings is translated into the angle between the formed halogen bonds. © 2013 The Royal Society of Chemistry

Electric field effects on the dynamics of bubble detachment from an inclined surface

An experimental apparatus to study bubble detachment from an inclined surface under the action of electric forces is described. It consists of a container filled with FC72 at room temperature and pressure where a train of gas bubbles is injected from an orifice. An electrostatic field can be imposed around the bubble, while the cell can be tilted from 0 to 90°. It is possible to study interface growth with the aid of high-speed cinematography. Since the interface is asymmetrical, a mirror system allowed to acquire, in the same frame, two images at 90° of the bubble. Different inclinations, injection rates and voltages were tested in order to couple the effects of shear gravity and electric field. Curvature and contact angles have been derived with appropriate interpolation methods of the profile. Force balances on the bubble were checked, finding an electric force, which, at first pulls the bubbles from the orifice, then pushes it against the surface. The motion of the center of gravity confirms this behaviour. A power balance has been developed to determine the energy contributions, revealing that surface growth incorporates both the effects of inlet power and electric field

The Genetics of Non-Syndromic Primary Ovarian Insufficiency: A Systematic Review

Several causes for primary ovarian insufficiency (POI) have been described, including iatrogenic and environmental factor, viral infections, chronic disease as well as genetic alterations. The aim of this review was to collect all the genetic mutations associated with non-syndromic POI. All studies, including gene screening, genome-wide study and assessing genetic mutations associated with POI, were included and analyzed in this systematic review. Syndromic POI and chromosomal abnormalities were not evaluated. Single gene perturbations, including genes on the X chromosome (such as BMP15, PGRMC1 and FMR1) and genes on autosomal chromosomes (such as GDF9, FIGLA, NOBOX, ESR1, FSHR and NANOS3) have a positive correlation with non-syndromic POI. Future strategies include linkage analysis of families with multiple affected members, array comparative genomic hybridization (CGH) for analysis of copy number variations, next generation sequencing technology and genome-wide data analysis. This review showed variability of the genetic factors associated with POI. These findings may help future genetic screening studies on large cohort of women

Halogen Bonding beyond Crystals in Materials Science

Halogen bonding has recently gained well deserved attention in present-day research for its importance in many fields of supramolecular science and crystal engineering. Although generally overlooked in comprehensive studies in the past, halogen bonding has become an important tool also in the field of materials science. An increased number of scientific reports are published every year where halogen bonding is exploited in soft materials rather than in crystal engineering. Here, we focus on a description of the most exciting contemporary developments in the field of halogen-bonded functional soft materials, assembled using the guiding principles of crystal engineering. We give a particular emphasis to those published in the past few years