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  • Open access
  • 21 Reads
Effect of ohmic heating nixtamalization on the structural and physicochemical characteristics of instant maize flours and their relation to starch modifications

The study investigated the changes in the physicochemical properties of maize starch on nixtamalized flours produced with ohmic heating under different voltage and thermal conditions. Changes were studied using their viscosity profile, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results indicated flour viscosity was affected by increasing time/temperature, but also by greater electrical fields, due to gelatinization and electroporation, shown as damage of the starch granule in SEM. DSC and XRD indicated gelatinization and loss of crystalline structures, but also formation of new amylose-lipid interactions stabilizing the starch system and causing lower peak viscosity.

  • Open access
  • 33 Reads
A beneficial bio-waste with a zero-waste approach: peanut shell

The recycling of food and agricultural wastes, which are released as a result of domestic and agricultural uses, instead of throwing them into the garbage cycle and the environment, is of great importance both for the protection of the environment and the minimization of other environmental pollutants. In recent years, human population growth, pandemic developments (COVID-19), climate change, and global warming have increased significantly. These increases endanger environmental health. Therefore, researchers are investigating different alternatives in terms of both human and environmental health. This paper evaluates the possible use of the shell part of peanut, which is a food with high nutritional value. Peanut (Arachys hypogaea) is a plant from the Fabaceae family. Peanut is a valuable food product with a wide range of uses all over the world. Their shells are an indispensable part of the garbage cycle and have fibrous and lignocellulosic (cellulose content: 45%, hemicellulose content: 6%, lignin content: 36%) structure. In addition, it has a very slow degradation rate under natural conditions, which is a great advantage for other wastes. Today, most peanut shells are disposed of by incineration and burial, which causes environmental pollution. For this reason, this waste should be used in various sectors with a zero-waste approach. Increasing environmental pollution all over the world day by day, unconscious energy consumption, and climate change have led countries to seek alternative solutions for environmental issues and to develop environmentally friendly-technological methods. Peanut shell is used intensively in fields such as compost material, the energy sector (biofuel, biodiesel, CO2 emission reduction, etc.), cosmetics sector (nail polish, lipstick, etc.), soil improvement, drinking water and wastewater treatment (adsorbent, nanomaterial, filter, etc.). In this study, the use of peanut shells from Osmaniye province as an environmentally friendly, economical, and easily available biosorbent was investigated.

  • Open access
  • 20 Reads
Study on the changes of urine differential protein expression of female athletes after different intensity treadmill exercise

Objective: to apply proteomics technology to detect the expression of differential proteins in the urine of female athletes after treadmill running at different intensities, and to explore the changes of urinary protein components after different intensities of exercise and their correlation with human immune function and exercise-induced fatigue, so as to provide scientific basis and practical methods for exercise biochemical monitoring.

Methods: two dimensional electrophoresis was used to analyze the differential expression of urine proteome map of 10 female athletes after treadmill exercise at the intensity of 40%, 60%, 70% and 90% maximum oxygen uptake respectively. Egg white spots with up regulation of differential protein expression ≥ 5 times and repeatability after exercise were selected and analyzed by matrix assisted laser desorption ionization tandem time of flight mass spectrometry.

Results: there were 261 differential protein spots of urine proteome after four different intensities of exercise determined by two-dimensional electrophoresis, including 76 down-regulated protein spots and 185 up-regulated protein spots; A total of 23 proteins, including zinc, were identified by mass spectrometry- α 2-glycoprotein, apolipoprotein, vitamin D binding protein, albumin, complement protein C3, immunoglobulin, etc; The analysis shows that the functions of these differential proteins are closely related to the biological processes of immune regulation and inflammatory response.

Conclusion: proteomic analysis can better explain the changes of urinary protein components after exercise, including apolipoprotein and zinc- α 2-glycoprotein is related to energy metabolism after exercise, immunoglobulin, albumin, complement protein C3, mannose binding lectin related protein 19 and vitamin D binding protein are related to immune regulation after exercise, which provides a theoretical basis and application method for investigating the changes of human immune function and fatigue state after women's exercise training.

  • Open access
  • 60 Reads
Use of mango by-products in the development of functional confectionery

The mango (Mangifera indica L.) is one of the most cultivated fruits in the world, however, its processing generates high amounts of waste, called agro-industrial by-products, among which the stone or seed, peel and bagasse stand out. It has been reported that these by-products contain significant amounts of nutrients and phytochemicals, mainly fiber and phenolic compounds, which represent a potential added value for the food industry, which has increased the interest in their study and applications by various authors. One of these booming applications is functional confectionery, which represents a vehicle for taking advantage of the benefits of these by-products. Therefore, the present work seeks to develop and evaluate the effect of a functional confectionery product (gummy) enriched with different concentrations of bagasse and mango peel on the texture profile characteristics (TPA), essential for sensory evaluation, selecting the mixture with greater similarity to the commercial product for its subsequent proximal characterization. As a result, for mixture 2, which contains a high pectin and bagasse content, added to a low shell content, with respect to the other mixtures, it presents a TPA profile similar to the control commercial gummy. The proximal composition showed 41% carbohydrates, of which 59% belongs to total dietary fiber, divided into 26% soluble and 33% insoluble. When performing the Pearson correlation of mixtures vs. the texture profile, the hardness parameter is negatively correlated with the type of mixture, which in turn is related to both the gumminess and the chewiness of the product. These results suggest that it is possible to incorporate these agro-industrial by-products into food and that it is comparable with that already marketed. In addition, with its high percentage of fiber, it could be considered a potentially prebiotic food.

  • Open access
  • 16 Reads
Stability and in vitro biosafety study of an emulsion of Calendula officinalis L. with potential application in treating skin burn wounds

Skin burns are injuries of different degrees of complexity (first to third) caused by physical and/or chemical trauma. There is a necessity to improve the rapid retrieval of superficial wounds (first grade) to enhance epithelization, avoiding dehydration, infections, and scar formation. This work proposes an oil in water (O/W) emulsion based on 1% of Calendula officinalis L. extract, due its recognized traditional uses as medicinal plant in wound care, with reported beneficial secondary metabolites such as Carotenoids, Terpenoids, Flavonoids, Coumarins and Quinones. The rheologi-cal characterization of the obtained emulsions indicated superior stability over time (2 months) and a pseudoplastic and semisolid fluid behavior. Furthermore, the emulsions were evaluated biologi-cally in terms of biosafety in vitro with promising results that showed a non-hemolytic behavior (below 14.53%) and a moderate platelet aggregation (33.66%) tendency, which is beneficial as it can contribute to enhancing the healing process. Additionally, the emulsions were characterized physi-cochemically by frequency curve, flow curves of shear stress, and viscosity. Currently, we are con-ducting a droplet size distribution assay, and conducting 2D wound healing assays in a scratch model over a monolayer of keratinocytes. Thus far, the results hold much promise and indicate that these emulsions can be potentially employed in the treatments of burn wounds.

  • Open access
  • 44 Reads
pH-dependent specificity of papain-like cysteine proteases is determined by S1 binding pocket

Papain-like cysteine proteases (PLCPs) are widely expressed enzymes, the main function of which is low-specific protein turnover in the acidic conditions of lysosomes. Additionally, these proteases provide specific functions in other compartments such as cytosol, nucleus, and extracellular space. The specificity of each protease to its substrates mainly depends on the patterns of the amino acids in the binding cleft. This specificity is highly regulated by media conditions and the presence of accessory proteins. In this study, we examined structural aspects ensuring pH-dependent substrate specificity of PLCPs. Experiments employing fluorogenic peptide substrates demonstrated that plant PLCPs and human cathepsins possess a pH-dependent specificity for the residue in the P1 position. X-ray crystallographic studies and molecular simulations allowed overall structure determination of the enzymes to predict residues in the S1 binding pocket which can form electrostatic contacts with the substrates. Sequence analysis established variability of these residues among PLCPs. Based on the obtained data we designed a peptide inhibitor for human cathepsin L and described its inhibitory potential. As a conclusion, we state that the S1 binding pocket defines specific pH-dependent recognition of substrates by PLCPs, ensuring multiple physiological functions of these proteases. This work was supported by the Russian Science Foundation (grant No. 22-25-00648).

  • Open access
  • 35 Reads
Study of spheroids fusion via multiphysics simulations: feasibility of applying permanent magnetic field gradients

Cell spheroids represent a scaffold-free route to form cell aggregates through maximizing cell-cell interactions. Spheroids have gained signifcant attention for the engineering of multilayer tissues as they offer a closer resemblance of physiological conditions observed in vivo, compared with traditional 2D models where cells are grown on flat surfaces. Multilayered tissues are formed by allowing spheroids to interact with themselves within relevant matrices mimicking native conditions of extracellular matrices. However, such conventional fusion methods provide little control over spheroid-spheroid interactions, making their reproducibility very limited. Additionally, such methods are lengthy, which is undesirable from the scalability and economic viewpoints. We propose a methodology to accelerate spheroid fusion by applying magnetic forces externally on spheroids previously magnetized by internalization of magnetite nanoparticles with potent translocating proteins and peptides. A base mathematical model of spheroids assembly was implemented in COMSOL Multiphysics and involved a laminar two-phase field approach, which was validated by employing a novel segmentation algorithm. The magnetic effect was introduced by an applied volumetric magnetic force, which was generated by the action of two neodymium permanent magnets positioned perpendicular to the computational domain. Our simulations showed that magnetized spheroids fusion can be accelerated by about 55% after applying a magnetic force. In addition, we successfully tested a new modeling approach that allowed taking into account interactions between spheroids and the medium as evidenced by a standard error of only 13% between simulations and experimental results shown in the literature. Importantly, these simulations also showed that the time required to fuse spheroids is reduced by about 55%. We are currently validating the model experimentally on extracellular-matrix-derived hydrogels embedded with the magnetized spheroids. Future work will be dedicated to calibrating the model with the collected experimental data.

  • Open access
  • 24 Reads
Structural and Conformational Dynamics of a Disordered Protein Motif
, , , ,

SALS (sarcomere length short), a WH2-domain-containing protein was identified in Drosophila as an important regulator of the assembly of sarcomeric actin structures (Bai et al.(1)). It contributes to the establishment of sarcomere length and organization by promoting the lengthening of actin filaments at the pointed end. The absence of SALS is already lethal in the embryonic age. This may be due to the shortening of the length of sarcomeric actin filaments, and/or the disruption of their organization.

SALS is a relatively large protein, consisting of 935 amino acids. According to our bioinformatics analysis, it is an intrinsically disordered protein (IDP). IDPs are biologically active proteins, that, however, do not have a well-defined three-dimensional structure. They possess specific physicochemical properties, different from those of ordered proteins (e.g. hydrophilic/charged:hydrophobic amino acid ratio, thermal stability, electrophoretic mobility).

In the case of SALS previous studies have revealed only two motifs consisting of a few 10 amino acids, called Wiscott-Aldrich syndrome homology 2 (WH2) domains, that are intrinsically disordered protein regions (IDR) of low structural complexity. Considering their role, they possess actin-binding properties. Depending on the number and sequence of domains, proteins containing WH2 show multifunctional properties.

In our previous research we completed the functional analysis of the SALS WH2 domains (SALS-WH2) (2). Based on our results both of the SALS WH2 domains interact with the actin, and through their activities shift the monomer:filament ratio towards monomeric actin. We further aimed to characterize the structural and conformational dynamic properties of SALS-WH2 by using in silico and experimental approaches. Our bioinformatics analysis suggests that the SALS-WH2 domains have IDR elements. Our prediction-based results were experimentally verified by fluorescence spectroscopy and thermal analysis.

(1) Bai J, Hartwig JH, Perrimon N. SALS, a WH2-domain-containing protein, promotes sarcomeric actin filament elongation from pointed ends during Drosophila muscle growth. Dev Cell.2007 Dec;13(6):828-42.

(2) Tóth MÁ, Majoros AK, Vig AT, Migh E, Nyitrai M, Mihály J, Bugyi B. Biochemical Activities of the Wiskott-Aldrich Syndrome Homology Region 2 Domains of Sarcomere Length Short (SALS) Protein. J Biol Chem. 2016 Jan 8;291(2):667-80.

New National Excellence Program of the Ministry for Innovation and Technology ÚNKP-21-3-II-PTE-997 (PG), University of Pécs, Medical School, KA-2021-30 (AV). We thank József Mihály (Institute of Genetics, Biological Research Centre) for the SALS plasmid.

  • Open access
  • 9 Reads
LiveMIEL: Genetically encoded epigenetic probes for enhancers dynamics visualization in live-cell fluorescence microscopy
, ,

Histone post-translational modifications (namely acetylation, methylation, phosphorylation, and some others, less abundant) play a significant role in chromatin structure and functioning [1]. In live cells specific histone modifications reader domains (HMRD) existing as parts of regulatory proteins and multiprotein complexes, are usually responsible for the recognition and interaction with such modifications [2]. However, it is still not entirely understood how these chromatin modifications affect the overall genome organization and their response to various cellular events.

In 2019 Prof. Terskikh and co-authors have developed a novel method for high-throughput analysis of epigenetic changes at the single-cell level, called Microscopic Imaging of Epigenetic Landscapes (MIEL) [3]. The pipeline of this approach includes staining of fixed cells with antibodies specific to certain histone modifications, which is followed by image analysis applying machine learning to classify and compare epigenetic patterns (landscapes). High applicability of the method to detect changes of epigenetics during drug treatment and cell differentiation was shown.

Here, based on the forementioned method, we present specific genetically encoded epigenetic probes (GEEPs), developed for adaptation of MIEL for live-cell fluorescence microscopy. GEEPs rely on the natural specificity of the HMRD to certain modifications instead of antibodies, allowing for the visualization of epigenetic landscape dynamics followed by computational analysis. These probes can be used for different cell types due to their versatility and low toxicity. They are widely applicable to a number of research tasks, namely drug development, cancer and aging research, along with fundamental studies.

Our particular interest is focused on enhancer regions dynamics. Enhancers, regulatory elements controlling gene expression, actively interact with the gene promoters. However, unlike promoters, they can perform their regulatory functions regardless of their orientation or certain spatial segregations from their target genes. Large clusters of active enhancers comprise super-enhancers which are responsible for transcriptional regulation of cell identity genes. Primed enhancers prior to activation are generally marked with H3K4me1 modification while active enhancers and super-enhancers are enriched in both H3K4me1 and H3K27ac. Poised enhancers, on the other hand, show high levels of the H3K27me3 repression mark, which is to be removed to make the enhancer activation possible [4]. We utilize these features to develop GEEPs for enhancer and super-enhancer dynamics visualization.

References

  1. Sadakierska-Chudy A, Filip M. A comprehensive view of the epigenetic landscape. Part II: Histone post-translational modification, nucleosome level, and chromatin regulation by ncRNAs. Neurotox Res. 2015;27: 172–197.
  2. Musselman CA, Lalonde M-E, Côté J, Kutateladze TG. Perceiving the epigenetic landscape through histone readers. Nat Struct Mol Biol. 2012;19: 1218–1227.
  3. Farhy C, Hariharan S, Ylanko J, Orozco L, Zeng FY, Pass I, Ugarte F, Forsberg EC, Huang CT, Andrews DW, Terskikh AV. Improving drug discovery using image-based multiparametric analysis of the epigenetic landscape. Elife. 2019 Oct 22;8:e49683. doi: 10.7554/eLife.49683.
  4. Sharifi-Zarchi A, Gerovska D, Adachi K, Totonchi M, Pezeshk H, Taft RJ, et al. DNA methylation regulates discrimination of enhancers from promoters through a H3K4me1-H3K4me3 seesaw mechanism. BMC Genomics. 2017;18: 964.
  • Open access
  • 28 Reads
Design of enzyme stabilization systems for gas separation: Novel studies on formation of enzyme based W/O emulsions by direct membrane emulsification to synthesise emulsion-based supported liquid membrane for CO2 capture

Membrane-based gas separation is an important unit operation in chemical industries due to its simplicity, ease of operation, reduced energy consumption and compact structure. For gas separation, novel studies were carried out by synthesising enzyme stabilised systems consisting of emulsion-based supported liquid membranes (E-SLMs) wherein their pores were impregnated with water-in-oil (W/O) emulsions produced by direct membrane emulsification. This technique has gained attention as it consumes low energy and is mild, suitable for sensitive enzymes.

This case study involves the capture of CO2 by the enzyme carbonic anhydrase (CA). The composition of oil phase was optimised amongst various edible oils aiming for the one with the highest CO2 sorption capability. The water phase was optimised based on the stability of CA enzyme in aqueous phase in the presence of various surfactants and their concentrations. The optimised emulsions consisted of 2% Tween 80 (w/w) in corn oil as continuous phase and 0.5 g.L-1 CA enzyme with 5% PEG300 (w/w) in aqueous solution as the dispersed phase. The emulsions were prepared with Microdyn Nadir UP150 polymeric membrane. These emulsions were impregnated onto a hydrophobic PVDF membrane to prepare E-SLM. For comparative studies, liquid membranes were also prepared without the CA enzyme in the emulsions, and a supported liquid membrane (SLM) was prepared by impregnating corn oil onto the membrane.

Lastly, the permeabilities of the main components of biogas, CO2 and CH4, through the SLM and E-SLMs were evaluated. The permeability of CO2 increased (~15%) and CH4 decreased (~60%) through the E-SLM containing CA when compared to the SLM and E-SLM without CA. Subsequently, the selectivity of CO2 increased in the presence of low concentration of CA. This work suggests the enhanced, synergetic effects of carbonic anhydrase within a bio-based emulsion system for CO2 capture.

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