Valorizarea legumelor și fructelor ecologice sub forma de produse alimentare cu valoare adaugata - studiu de piata

Prezentarea "Valorizarea legumelor și fructelor ecologice sub forma de produse alimentare cu valoare adaugata - studiu de piata" sustinuta de studenta Ioana Oprica in cadrul Simpozionului „Tineri cercetatori în Horticultura, Silvicultură și Biotehnologii” - Editia a V-a la USAMVB Timisoara a fost apreciata cu Premiul II

Variation of bioactive compounds in organic Ocimum basilicum L. during freeze-drying processing

Abstract Common basil (Ocimum basilicum L.), one of the most important aromatic perennial herbs due to its essential oil composition, belongs to Lamiaceae (Labiatae) family. Basil is an economically important herb and it is considered one of the finest aromatic herbs, being widely used as flavor in food industry. Basil samples were characterized in terms of chlorophyll content, total polyphenols, antioxidant activity, and volatile oil content. The fresh harvested leaves and the processed powder from leaves were hydro-distilled for 3 h in a Clevenger-type apparatus. The volatile oil was measured and collected for further GC-MS analysis. As drying technology, freeze-drying was used until the samples reached a loss of 85% from the fresh weigh, with the final dry matter content of 95.86%. Variations for the main constituents of volatile oil: 1,8-cineole, linalool, methyl chavicol, eugenol, α-bergamotene, and α-epi-cadinol were observed after processing

Mapping hydrophobicity on the protein molecular surface at atom-level resolution

A precise representation of the spatial distribution of hydrophobicity, hydrophilicity and charges on the molecular surface of proteins is critical for the understanding of the interaction with small molecules and larger systems. The representation of hydrophobicity is rarely done at atom-level, as this property is generally assigned to residues. A new methodology for the derivation of atomic hydrophobicity from any amino acid-based hydrophobicity scale was used to derive 8 sets of atomic hydrophobicities, one of which was used to generate the molecular surfaces for 35 proteins with convex structures, 5 of which, i.e., lysozyme, ribonuclease, hemoglobin, albumin and IgG, have been analyzed in more detail. Sets of the molecular surfaces of the model proteins have been constructed using spherical probes with increasingly large radii, from 1.4 to 20 A˚, followed by the quantification of (i) the surface hydrophobicity; (ii) their respective molecular surface areas, i.e., total, hydrophilic and hydrophobic area; and (iii) their relative densities, i.e., divided by the total molecular area; or specific densities, i.e., divided by property-specific area. Compared with the amino acid-based formalism, the atom-level description reveals molecular surfaces which (i) present an approximately two times more hydrophilic areas; with (ii) less extended, but between 2 to 5 times more intense hydrophilic patches; and (iii) 3 to 20 times more extended hydrophobic areas. The hydrophobic areas are also approximately 2 times more hydrophobicity-intense. This, more pronounced "leopard skin"-like, design of the protein molecular surface has been confirmed by comparing the results for a restricted set of homologous proteins, i.e., hemoglobins diverging by only one residue (Trp37). These results suggest that the representation of hydrophobicity on the protein molecular surfaces at atom-level resolution, coupled with the probing of the molecular surface at different geometric resolutions, can capture processes that are otherwise obscured to the amino acid-based formalism

Models of protein linear molecular motors for dynamic nanodevices

Protein molecular motors are natural nano-machines that convert the chemical energy from the hydrolysis of adenosine triphosphate into mechanical work. These efficient machines are central to many biological processes, including cellular motion, muscle contraction and cell division. The remarkable energetic efficiency of the protein molecular motors coupled with their nano-scale has prompted an increasing number of studies focusing on their integration in hybrid micro- and nanodevices, in particular using linear molecular motors. The translation of these tentative devices into technologically and economically feasible ones requires an engineering, design-orientated approach based on a structured formalism, preferably mathematical. This contribution reviews the present state of the art in the modelling of protein linear molecular motors, as relevant to the future design-orientated development of hybrid dynamic nanodevices. © 2009 The Royal Society of Chemistry

Protein molecular surface mapped at different geometrical resolutions

Many areas of biochemistry and molecular biology, both fundamental and applications-orientated, require an accurate construction, representation and understanding of the protein molecular surface and its interaction with other, usually small, molecules. There are however many situations when the protein molecular surface gets in physical contact with larger objects, either biological, such as membranes, or artificial, such as nanoparticles. The contribution presents a methodology for describing and quantifying the molecular properties of proteins, by geometrical and physico-chemical mapping of the molecular surfaces, with several analytical relationships being proposed for molecular surface properties. The relevance of the molecular surface-derived properties has been demonstrated through the calculation of the statistical strength of the prediction of protein adsorption. It is expected that the extension of this methodology to other phenomena involving proteins near solid surfaces, in particular the protein interaction with nanoparticles, will result in important benefits in the understanding and design of protein-specific solid surfaces. © 2013 Nicolau et al

A mechanical model for the motility of actin filaments on myosin

The interaction of actin filaments with myosin is crucial to cell motility, muscular contraction, cell division and other processes. The in vitro motility assay involves the motion of actin filaments on a substrate coated with myosin, and is used extensively to investigate the dynamics of the actomyosin system. Following on from previous work, we propose a new mechanical model of actin motility on myosin, wherein a filament is modeled as a chain of beads connected by harmonic springs. This imposes a limitation on the "stretching" of the filament. The rotation of one bead with respect to its neighbours is also constrained in similar way. We implemented this model and used Monte Carlo simulations to determine whether it can predict the directionality of filament motion. The principal advantages of thismodel over our previous one are that we have removed the empirically correct but artificial assumption that the filament moves like a "worm" i.e. the head determines the direction of movement and the rest of the filament "follows" the head as well as the inclusion of dependencies on experimental rate constants (and so also on e.g. ATP concentration) via the cross-bridge cycle

Impact of protein adsorption on the geometry of microfluidics devices

'Lab-on-a-chip' microfluidics devices manipulate biological fluids, which contain significant quantities of biomolecules, in particular proteins and DNA, and even living cells. As the dimensions of these devices continue to decrease and approach the sub-micron range, and as the trend towards 'disposable' devices continues, the impact of the inevitable adsorption of biomolecules becomes more important. In this paper we estimated the protein-adsorption-related sensitivity of the geometry of a rectangular micron-sized channel. The estimation the thickness of the adsorbed protein layer versus processing parameters, i.e., protein concentration in the fluid; ionic strength of fluid; and surface tension of the walls, is based on a proposed semi-empirical model for protein adsorption. The model, derived from the data contained in a biomolecule adsorption database, uses the concept of a 'generic protein', i.e., a protein with molecular properties averaged over the range of data present in the database. The estimation of protein-adsorption-related impact on the geometry of a rectangular micron-sized channel, i.e., narrowing of the micro-channel, increases dramatically below a threshold value of approximately 1.5-2 μm

Alternative designs for biosensors based on protein molecular motors

Abstract not available

A C library for simulating P systems

The present paper describes an ANSI C library which has been developed to facilitate the implementation and simulation of P systems on a computer. Simple data structures are proposed which permit the representation of membranes and their associated objects, and facilities are provided for implementing both "active" and "non-active" membrane systems, including actions for dissolving a membrane, dividing an existing membrane and creating a new membrane

Tracking control for a flat system under disturbances: a fixed-wing UAV example

International audienceThis paper considers a class of systems admitting several flat representations and proposes a trajectory tracking controller design which accounts for disturbance rejection. Set invariance is used for characterizing the tracking and estimation error dynamics. Furthermore, some insights on the disturbance propagation in case of different flat representations for a fixedwing Unmanned Aerial Vehicle (UAV) system are highlighted via simulations and comparisons