Biogenic Ferrihydrite Nanoparticles Produced by Klebsiella oxytoca: Characterization, Physicochemical Properties and Bovine Serum Albumin Interactions

The synthesis of nanoparticles inside microorganisms is an economical alternative to chemical and physical methods of nanoparticle synthesis. In this study, ferrihydrite nanoparticles synthesized by Klebsiella oxytoca bacterium in special conditions were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), small-angle X-ray (SAXS), UV-Vis spectroscopy, fluorescence, fluorescence resonance energy transfer (FRET), and molecular docking. The morphology and the structure of the particles were characterized by means of SEM and SAXS. The elemental content was determined by means of the EDS method. The absorption properties of the ferrihydrite nanoparticles were investigated by UV-Vis spectroscopy. The binding mechanism of the biogenic ferrihydrite nanoparticles to Bovine Serum Albumin (BSA) protein, studied by fluorescence, showed a static and weak process, combined with FRET. Protein denaturation by temperature and urea in the presence of the ferrihydrite nanoparticles demonstrated their influence on the unfolding process. The AutoDock Vina and UCSF Chimera programs were used to predict the optimal binding site of the ferrihydrite to BSA and to find the location of the hydrophobic cavities in the sub-domain IIA of the BSA structure.

The Effect of Batter Characteristics on Protein-Aided Control of Fat Absorption in Deep-Fried Breaded Fish Nuggets

Soy protein (SP), egg white protein (EP), and whey protein (WP) at 6% w/w were individually incorporated into the batter of a wheat starch (WS) and wheat gluten (WG) blend (11:1 w/w ratio). Moisture adsorption isotherms of WS and proteins and the viscosity, rheological behavior, and calorimetric properties of the batters were measured. Batter-breaded fish nuggets (BBFNs) were fried at 170 °C for 40 s followed by 190 °C for 30 s, and pick-up of BBFNs, thermogravimetric properties of crust, and fat absorption were determined. The moisture absorption capacity was the greatest for WS, followed by WG, SP, EP, and WP. The addition of SP significantly increased the viscosity and shear moduli (G″, G′) of batter and pick-up of BBFNs, while EP and WP exerted the opposite effect (p < 0.05). SP, EP, and WP raised WS gelatinization and protein denaturation temperatures and crust thermogravimetry temperature, but decreased enthalpy change (ΔH) and oily characteristics of fried BBFNs. These results indicate that hydrophilicity and hydration activity of the added proteins and their interactions with batter matrix starch and gluten reinforced the batter and the thermal stability of crust, thereby inhibiting fat absorption of the BBFNs during deep-fat frying.

Scyphocephalione a Isolated from the Stem Bark of Scyphocephalium Ochocoa (Myristicaceae) Attenuate Acute and Chronic Pains Through the Antiinflammatory Activity

Abstract In the treatment of cancer, patients that receive anti-cancer drugs such as Vincristine develop peripheral neuropathic pain. Scyphocephalione A is a new bioactive compound isolated from Scyphocephalium ochocoa (Myristicaceae), a medicinal plant traditionally used in African countries. Recently, an in vitro study has shown its anti-inflammatory and cytotoxic activities on MCF-7 cell line of mammary carcinoma. The purpose of the present study was to assess the in vitro anti-inflammatory and in vivo anti-nociceptive activities of Scyphocephalione A. In vitro tests were carried out on cyclooxygenase and 5-lipoxygenase activities, and on protein denaturation; while in vivo tests were performed on acute and chronic pain models. It was noticed that, Scyphocephalione A (1000 µg/ml), inhibits proteins denaturation, cyclooxygenase and 5-lipoxygenase activities respectively by 74.21%, 75.80% and 64.43%. The dose 50 mg/kg of Scyphocephalione A, inhibits acetic acid (63.43%, p<0.001) and formalin (42.12% (p<0.001) within first phase and 67.53% (p<0.001) within second phase)-induced pains. At the same dose, Scyphocephalione A significantly inhibited mechanical and heat hyperalgesia, as well as cold allodynia induced by vincristine. In addition, the compound restored haematological, biochemical and oxidative stress parameters which were altered following Vincristine administration. These results suggest that Scyphocephalione A is endowed with anti-inflammatory potential and antinociceptive properties. Therefore, Scyphocephalione A can be classified as a promising molecule for the management of peripheral neuropathic pain triggered by anti-cancer drug.

Preliminary Phytochemical Analysis: In-Vitro Comparative Evaluation of Anti-arthritic and Anti-inflammatory Potential of Some Traditionally Used Medicinal Plants

Background: Colchicum autumnale, Strychnous nux-vomica and Aloe barbadensis are the medicinal plants clinically utilized for the management of rhuematic disorders. Purpose: The present work was focused to evaluate the in-vitro anti-arthritic and anti-inflammatory activities of Colchicum ( Colchicum autumnale), Nux-vomica ( Strychnous nux-vomica), and Aloe-vera ( Aloe barbadensis). Research Design: Primarily, the aqueous-ethanolic extracts of these medicinal plants were phytochemically screened followed by Fourier Transform Infrared (FTIR) analysis. Anti-arthritic activity by protein denaturation method and anti-inflammatory activity by human red blood cell (HRBC) membrane stabilization method at the concentration of 125, 250, and 500 µg/mL along with standard were performed. Results: Phytochemical screening revealed that alkaloids, saponins, terpenoids, phenols, and anthraquinones were found in all the extracts, and organic acids, amine group, aromatic or aliphatic compounds, esters and halogens, and phenolics were identified by FTIR. Protein denaturation method revealed that colchicum, nux-vomica, and aloe-vera showed maximum 98.5%, 99.6%, and 72.3% of inhibition at 500 µg/mL compared with that of standard drug, that is, Diclofenac sodium. Membrane stabilization method showed that colchicum, nux-vomica, and aloe-vera showed maximum 40.20%, 35.67%, and 40.1% protection at 500 µg/mL when compared with standard drug. Conclusion: It is concluded from the current study that extracts of colchicum, nux-vomica, and aloe-vera showed more potent effect and thus can be used as alternative options for the management of inflammatory and arthritic ailments.

Batch Production of High-Quality Graphene Grids for Cryo-EM: Cryo-EM Structure of Methylococcus capsulatus Soluble Methane Monooxygenase Hydroxylase

Cryogenic electron microscopy (cryo-EM) has become a widely used tool for determining protein structure. Despite recent advances in instruments and algorithms, sample preparation remains a major bottleneck for several reasons, including protein denaturation at the air/water interface and the presence of preferred orientations and nonuniform ice layers. Graphene, a two-dimensional allotrope of carbon consisting of a single atomic layer, has recently attracted attention as a near-ideal support film for cryo-EM that can overcome these challenges because of its superior properties, including mechanical strength and electrical conductivity. Graphene minimizes background noise and provides a stable platform for specimens under a high-voltage electron beam and cryogenic conditions. Here, we introduce a reliable, easily implemented, and reproducible method of producing 36 graphene-coated grids at once within 1.5 days. The quality of the graphene grids was assessed using various tools such as scanning EM, Raman spectroscopy, and atomic force microscopy. To demonstrate their practical application, we determined the cryo-EM structure of Methylococcus capsulatus soluble methane monooxygenase hydroxylase (sMMOH) at resolutions of 2.9 and 2.4 angstrom using Quantifoil and graphene-coated grids, respectively. We found that the graphene-coated grid has several advantages; for example, it requires less protein, enables easy control of the ice thickness, and prevents pro-tein denaturation at the air/water interface. By comparing the cryo-EM structure of sMMOH with its crystal structure, we revealed subtle yet significant geometrical differences at the non-heme di-iron center, which may better indicate the active site configuration of sMMOH in the resting/oxidized state.

METAL-INDUCED PROTEIN DENATURATION: REGULARITIES, PATHOLOGICAL MANIFESTATIONS, AND IN VITRO MODELING

the ability of various metal ions to form complexes with proteins leads to the denaturation of the latter and the development of immune response. Such hapten effects cause the well-known phenomenon of nickel-allergic contact dermatitis. No less typical are side effects of gadolinium compounds, that are used as contrasts for magnetic resonance imaging, but cause the development of fibrosis. In both cases an important role belongs to the interaction of metal ions with collagen structures. The aim of our study was to compare in vitro effects of copper and nickel ions on destabilized products of collagen cleavage. Significant difference between these metals in their ability to induce aggregation at close to physiological pH values was shown. The influence on the aggregative process of the acidification of the medium was revealed. It was shown that destabilization of protein structure leads to the formation of highly stabilized β-stacked protein aggregates. Comparison of the obtained experimental data with the literature ones makes it possible to approach the understanding of individual mechanisms of toxic effects of metal ions on the human body.

Mechanisms of Change in Emulsifying Capacity Induced by Protein Denaturation and Aggregation in Quick-Frozen Pork Patties with Different Fat Levels and Freeze–Thaw Cycles

Herein, we discuss changes in the emulsifying properties of myofibrillar protein (MP) because of protein denaturation and aggregation from quick-frozen pork patties with multiple fat levels and freeze–thaw (F–T) cycles. Protein denaturation and aggregation were confirmed by the significantly increased surface hydrophobicity, turbidity, and particle size, as well as the significantly decreased solubility and absolute zeta potential, of MPs with increases in fat levels and F–T cycles (p < 0.05). After multiple F–T cycles, the emulsifying activity and emulsion stability indices of all samples were significantly reduced (p < 0.05). The emulsion droplets of MP increased in size, and their distributions were dense and irregular. The results demonstrated that protein denaturation and aggregation due to multiple F–T cycles and fat levels changed the distribution of surface chemical groups and particle sizes of protein, thus affecting the emulsifying properties.

A new express method for determining the number of cycles of freezing and thawing poultry meat

Temperature fluctuations cause significant harm to the quality of poultry meat and its food safety, both at various stages of storage and transportation, as well as sales. Repeated repeated defrosting and freezing lead to a violation of the integrity of cells or protein denaturation, which is accompanied by a change in the ratio of the forms of moisture binding to the product. In this regard, there is an urgent task of establishing the facts of thawing and freezing of poultry meat, determining the number of cycles of repeated freezing. This article is devoted to the development of a new express method for determining the number of cycles of freezing – thawing of a broiler at the stages of the life cycle of poultry products. As the number of «freeze-defrost» cycles increases, the peak area of the differential scanning calorimetry curve (DSC) decreases from 206.4 to 192.6 kJ/mol with electric stunning and from 168.6 to 151.5 kJ/mol with gas stunning, the melting peak temperature also decreases from 5.7 to 5.2 oC with electric stunning and from 5.0 to 4.0 oC with gas stunning. The DSC temperature program and recommendations for its use for monitoring broiler processing and storage processes accompanied by phase transformations of water have been developed.