Evolutionary origin and diversification of epidermal barrier proteins in amniotes.

The evolution of amniotes has involved major molecular innovations in the epidermis. In particular, distinct structural proteins that undergo covalent cross-linking during cornification of keratinocytes facilitate the formation of mechanically resilient superficial cell layers and help to limit water loss to the environment. Special modes of cornification generate amniote-specific skin appendages such as claws, feathers, and hair. In mammals, many protein substrates of cornification are encoded by a cluster of genes, termed the epidermal differentiation complex (EDC). To provide a basis for hypotheses about the evolution of cornification proteins, we screened for homologs of the EDC in non-mammalian vertebrates. By comparative genomics, de novo gene prediction and gene expression analyses, we show that, in contrast to fish and amphibians, the chicken and the green anole lizard have EDC homologs comprising genes that are specifically expressed in the epidermis and in skin appendages. Our data suggest that an important component of the cornified protein envelope of mammalian keratinocytes, that is, loricrin, has originated in a common ancestor of modern amniotes, perhaps during the acquisition of a fully terrestrial lifestyle. Moreover, we provide evidence that the sauropsid-specific beta-keratins have evolved as a subclass of EDC genes. Based on the comprehensive characterization of the arrangement, exon-intron structures and conserved sequence elements of EDC genes, we propose new scenarios for the evolutionary origin of epidermal barrier proteins via fusion of neighboring S100A and peptidoglycan recognition protein genes, subsequent loss of exons and highly divergent sequence evolution

Recovery of ammonia from wastewater through chemical precipitation

Chemical precipitation is a consolidated technique applied in wastewater treatment to remove and recover phosphorous and ammonium that remain in the effluent after the anaerobic digestion treatment. The precipitate is magnesium ammonium phosphate hexahydrate (MgNH4PO4·6H2O), also known as struvite, and it is sold as a slow-release fertiliser. However, the value of struvite is quite low and has a limited market. Furthermore, it precipitates with heavy metals and other impurities that need to be removed to make the fertiliser commercially viable. This study looked at the thermal decomposition of struvite to recover added value products and recycle the magnesium for further precipitation. A kinetic study was carried out to understand the mechanism of decomposition and the formation of the different solid phases, which is fundamental for the design and optimisation of the technology. The thermogravimetric study confirmed that thermal decomposition is possible, but ammonia could not be completely released below 250 °C. The thermal analysis also led to the determination of the energy required for the decomposition, found to be 1.87 kJ g−1, which also includes the evaporation of water and ammonia. The kinetic study through the isoconversional method showed the presence of two major reactions, and the model-fitting approach identified the diffusion model as the best fit for the first reaction. The activation energy of the first reaction found with this method was 0.24 kJ g−1, comparable with the data obtained from the isoconversional method. The two-stage decomposition reactions were proposed, and the final calcination product was confirmed as magnesium pyrophosphate, which could be used in agriculture or dissolved in diluted mineral acids solution to separate the phosphate from the magnesium

A roadmap towards a circular and sustainable bioeconomy through waste valorization

Municipal solid waste and food supply chain waste are globally generated in large quantities from various sectors including various stages of food supply chains, municipalities, open markets and catering services. A prevailing priority in the EU is to stimulate the transition towards a circular economy that fosters the promotion of sustainable and resource-efficient policies for long-term socio-economic and environmental benefits. Common practices for waste management include landfill disposal, anaerobic digestion, composting and wastewater treatment. Recently, new technologies have been introduced to produce value-added products from agricultural residues and food processing side streams. Integrated and holistic approaches for organic waste utilization as industrial feedstocks will boost the transition towards the bio-economy era. The establishment of circular economy would expand and diversify the market outlets of bio-based products. This review provides an overview of the current methods on waste and by-product streams bioconversion to develop biorefinery concepts

Electron microscopic analysis in the gecko Lygodactylus reveals variations in micro-ornamentation and sensory organs distribution in the epidermis that indicate regional functions

Possible pattern variations of micro-ornamentation in different areas of the skin in the gecko Lygodactylus have been analyzed by scanning and transmission electron microscopy. A map of micro-ornamentation present in various areas of the skin has been obtained. Differences in micro-ornamentation pattern and sensory organ distribution were detected. The “spinulated pattern” consists of shorter spinulae in dorsal versus ventral scales, and spinules are shorter in inner scale surface and hinge regions with respect to the outer scale surface. The spines derive from the accumulation of struts of corneous material mainly composed of corneous beta proteins (CBPs, formerly indicated as beta-keratins) that merge into pointed micro-ornamentation. The 3D-accumulation of CBPs within Oberhautchen cells can vary in some regions of different scales during Oberhautchen-beta cell differentiation, perhaps also under physical tensile forces derived from continuous scale growth. Three other main patterns of micro-ornamentation were detected and indicated as “corneous belts,” “corneous dendritic ramification,” and “serpentine-pit and groove.” These variations from the typical spinulated pattern present in gecko epidermis are interpreted as transitional regions where the accumulation of corneous material in Oberhautchen cells that merges with underlying beta-cells gives rise to nonspinulated surfaces. Spinulated sensory organs with bristles and lenticular-shaped or knob-like tactile corpuscles are more numerous in ventral scales of the tail tip close to adhesive pads and near the digital pads. These regions are likely those most involved in the fine control of movements and response to vibrational stimuli derived from air and objects movements, including potential preys or predators

Micro‐ornamentation patterns in different areas of the epidermis in the gecko Tarentola mauritanica reflect variations in the accumulation of corneous material in Oberhautchen cells

Micro-ornamentations characterize the surface of scales in lepidosaurians and are summarized in four main patterns, i.e., spi- nulated, lamellated, lamellate-dentate, and honeycomb, although variations of these patterns are present in different species. Although geckos are known to possess a spinulated pattern derived from the Oberhautchen layer, also other pattern variations of the spinulated micro-ornamentation are present such as those indicated as dendritic ramification, corneous belts, and small bare patches. The present study mainly describes the variation of micro-ornamentations present in scales of different skin regions in the Mediterranean gecko Tarentula mauritanica using scannig and transmission electron microscopy. The study reports that the accumulation of corneous material in Oberhautchen cells is not homogenous in different areas of body scales and, when mature, this process gives rise to different sculpturing on the epidermal surface generating not only spinulae but also transitional zones leading to the other main patterns. It is hypothesized that spinulae formation derives from the verti- cal and lateral symmetric growth of tubercolate, non-overlapped scales of geckos. Sparse areas also result smooth or with serpentine-ridges likely revealing the beta-layer located underneath and merged with the Oberhautchen. The eco-functional role of this variable micro-ornamentation in the skin of lizards however remains largely speculative

Human cell dedifferentiation in mesenchymal condensates through controlled autophagy

Tissue and whole organ regeneration is a dramatic biological response to injury that occurs across different plant and animal phyla. It frequently requires the dedifferentiation of mature cells to a condensed mesenchymal blastema, from which replacement tissues develop. Human somatic cells cannot regenerate in this way and differentiation is considered irreversible under normal developmental conditions. Here, we sought to establish in vitro conditions to mimic blastema formation by generating different three-dimensional (3D) condensates of human mesenchymal stromal cells (MSCs). We identified specific 3D growth environments that were sufficient to dedifferentiate aged human MSCs to an early mesendoderm-like state with reversal of age-associated cell hypertrophy and restoration of organized tissue regenerating capacity in vivo. An optimal auophagic response was required to promote cytoplasmic remodeling, mitochondrial regression, and a bioenergetic shift from oxidative phosphorylation to anaerobic metabolism. Our evidence suggests that human cell dedifferentiation can be achieved through autonomously controlled autophagic flux

Sezione trasversale di equilibrio dei corsi d'acqua rettilinei non vegetati

La tesi confronta le soluzioni della sezione trasversale di equilibrio dei corsi d’acqua in condizioni particolari e studia l’evoluzione temporale della sezione, per piccole perturbazioni della portata, attraverso condizioni intermedie di quasi equilibrio. Dai risultati ottenuti si osserva che perturbazioni a scala stagionale della portata producono cambiamenti impercettibili della sezione, essendo i tempi di risposta della stessa dell’ordine della scala geologicaope

Assessment of dynamic membrane filtration for biological treatment of old landfill leachate

This study investigated the behaviour of dynamic membrane (DM) filtration for the treatment of stabilised landfill leachate in a bench-scale pre-anoxic and aerobic submerged dynamic membrane bioreactor (DMBR). Four meshes with different openings (10, 52, 85 and 200 μm) were tested to support the development of DM. Differences were observed among the meshes in supporting the development of the cake layer constituting the DM. The treatment of landfill leachate had an impact on sludge characteristics resulting in deteriorated filtration performance of the DM. Effluent turbidity was often higher than 100 NTU for larger mesh pore size (85 and 200 μm). Low effluent turbidity was achieved with meshes with 10 and 52 μm (13 ± 2 and 26 ± 4 NTU, respectively) although at membrane fluxes lower than 10 L m− 2 h−1. The bioreactor exhibited a moderate organics removal of 50–60% and an ammonia oxidation between 80 and 90%. Incomplete nitrification was observed due to increased concentrations of free ammonia and free nitrous acid, with nitrite effluent concentrations up to 1062 mgNO2--N L−1. Due to the large presence of refractory organic matter in landfill leachate, denitrification was limited resulting in a total nitrogen removal of approximately 20%