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In this review, the physicochemical and conformational changes of myofibrillar proteins (MPs) of freeze-induced mince-based aquatic foods were comprehensively summarized in depth. Studies have demonstrated that temperature fluctuation and long-time freezing negatively affect food quality, resulting in texture alteration, drip fluid, flavor degradation, and nutrition loss due to MPs denaturation, aggregation, and oxidation. Attempts have been made in ice-recrystallization inhibition, freezing point depression, and ice shape and growth control for better cryopreservation. Moreover, to further minimize the quality deterioration, cryoprotectants were acknowledged to reduce the denaturation and aggregation of the MPs effectively. Recently, interest in novel functional ingredients, including oligosaccharides, protein hydrolysates, and natural polyphenols demonstrated excellent cryoprotective effects while avoiding health concerns and undesirable flavor caused by traditional sugar-based or phosphates-based cryoprotectants. Therefore, the present review provides a systematic overview of these low molecular weight multifunctional substances with a particular sequence and highlights their underlying mechanism in the inhibition of ice recrystallization the stabilization of MPs. [ABSTRACT FROM AUTHOR]

According to the Hofmeister series, thiocyanate is the strongest "salting in" anion. In fact, it has a strong denaturant activity against the native state of globular proteins. A molecular level rationalization of the Hofmeister series is still missing, and therefore the denaturant activity of thiocyanate also awaits a robust explanation. In the last years, different types of experimental studies have shown that thiocyanate is capable to directly interact with both polar and nonpolar groups of polypeptide chains. This finding has been scrutinized via a careful computational procedure based on density functional theory approaches. The results indicate that thiocyanate is able to make H‐bonds via both the nitrogen and sulfur atom, and to make strong van der Waals interactions with almost all the groups of polypeptide chains, regardless of their polarity. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Turmeric rhizomes (Curcuma longa) and black cumin seeds (Nigella sativa) are polyherbal ingredients used for the management of cancer and other chronic inflammatory diseases in Nigerian ethnomedicine. Previous studies have shown the antioxidant, anti-inflammatory, and anticancer activities of the individual plant extracts. However, the two spices have not been biologically potentiated in their combined form. Therefore, this study obtained essential oils (EOs) from the combined spices and evaluated their inhibitory effects on free radicals, protein denaturation, and cancer proliferation. The EOs were extracted by hydro-distillation (HD) and characterized by gas chromatography-mass spectrometry (GC-MS). In vitro antioxidant assessment was conducted based on DPPH, hydrogen peroxide (H2O2), nitric oxide (NO), and ferric ion (Fe3+) radical scavenging assays. The cytotoxicity of the oil against non-tumorigenic (HEK293) and cancerous (HepG2 and HeLa) cell lines was determined following the MTT cell viability assay. An in silico molecular docking analysis of the oil constituents was also performed. Six batches of EOs I–VI were afforded, comprising twenty-two major constituents, with aromatic Ar-turmerone being the most prominent compound. There was a marked improvement in the bioactivity of the oils upon repeated HD and as a combination. The batch VI oil exhibited the best activity, with a cytotoxicity (CC50) of 10.16 ± 1.69 µg/100 µL against the HepG2 cell line, which was comparable to 5-fluorouracil (standard, CC50 = 8.59 ± 1.33 µg/100 µL). In silico molecular docking suggested δ-curcumene, Ar-curcumene, Ar-turmerol, and Ar-turmerone among the promising compounds based on their high binding energy scores with NOX2, NF-κB, and mdm2 proteins. In conclusion, the oils from the turmeric–black cumin combined possess a considerable inhibition ability against free radicals, protein denaturation, and cancer proliferation. This study's findings further underscore the effectiveness of turmeric–black cumin as a polyherbal medicinal ingredient. [ABSTRACT FROM AUTHOR]

This study investigated the effects of isochoric freezing (IF) on the shelf-life and quality of raw bovine milk over a 5-week period. The results were compared with conventional refrigeration (RF) and refrigeration after pasteurization (HTST). The IF treatment process entailed storing liquid raw milk in isochoric chambers in thermodynamic equilibrium at -5 °C/77 MPa and -10 °C/96 MPa. Several parameters were analyzed, including microbiology count, physicochemical properties, indigenous enzyme activity, protein content, volatile organic compounds profile, and lipid degradation. Both raw and pasteurized milk experienced increases in the microbial level past the acceptable threshold (≥5.5 log CFU/mL) after 2 weeks and 5 weeks, respectively, leading to the deterioration of other parameters during storage. In comparison, microbiology count decreased significantly during storage for both IF treatment conditions but was more pronounced for the higher pressure (96 MPa) treatment, leading to undetectable levels of microorganism after 5 weeks. IF treatment maintained stable pH, titratable acidity, viscosity, lipid oxidation, volatile profiles, total protein content, and lactoperoxidase activity throughout the storage period. Color was preserved during IF treatment at -5 °C/77 MPa; however, color was impacted during IF treatment at -10 °C/96 MPa. Protein structures were also modified during pressurized storage in both IF treatments. Overall, the study demonstrated that isochoric freezing could significantly increase the shelf-life of milk by reducing microbiology activity, whilst maintaining its nutritional content. These results underscore the potential role of isochoric freezing as a valuable tool in eliminating pathogens while maintaining quality characteristics similar to raw milk over long storage periods.

The purpose of this study was to reduce the loss of spent laying hens during slaughtering by adjusting the parameters of scalding. The research object of this study was the spent laying hens with a rearing age of more than 400 days. The research meant to explore the effect of scalding methods on feather removing and muscle overheating. Three scalding parameters were set as follow: 65 ℃-3 min (high temperature scalding, HS), 60 ℃-4 min 20 s (medium temperature and slow scalding, MSS), and 58 ℃-4 min 20 s (low temperature and slow scalding, LSS). Broilers without scalding were set as the control group. The defeathering effect was characterized by measuring the feather retention force (FRF) and counting the number of feathers remaining after defeathering. The overheating degree of breast muscle was characterized by measuring meat color, depth of overheating area, DSC scanning and Raman spectrum scanning. The results showed that no significant difference in feather removal effects between HS treatments and LSS treatments, while the feather retention force and residual feather number of MSS treatment were significantly lower than those of the other two groups (P

Alpinia monopleura is one of the endemic plants of Sulawesi, and it has an extensive distribution in the region. Research on chemical compounds and biological activities of A. monopleura is essential to continue as an effort to support the utilization of native plants for medicine. The extract was obtained using the maceration method. The chemical compounds in the extract were identified using Liquid Chromatography Mass Spectrometry (LCMS). Bovine Serum Albumin (BSA) and molecular docking methods were used to evaluate the anti-inflammatory activity. Ten compounds contained in the extract were successfully identified, E-para-coumaric acid (1), trans-ferulaldehyde (2), 3,5,6-trihydroxy-4',7-dimethoxyflavone (3), nevadensin (4), malvalic acid (5), ent-16α,17-hydroxy-19-kauranoic acid (6), 3',5-dihydroxy-7,4'-dimethoxy flavone (7), saurufuran B (8), 5-hydroxy-7,8,2'-trimethoxyflavanone (9) and dehydroabietic acid (10). The anti-inflammatory activity of extracts from rhizomes and stems of A. monopleura were 8.62 and 10.59 mg/L, respectively. Some flavonoids (9 and 7) can bind strongly to specific residues around the COX-2 active site, such as Ser530, thereby interfering with the function of the COX-2 enzyme and reducing the production of pro-inflammatory prostaglandins. Thus, A. monopleura extract has the potential to inhibit inflammatory responses through molecular regulation of the COX-2 enzyme. [ABSTRACT FROM AUTHOR]

This study investigates the impact of dry heat pretreatment on the functionality of soy, chickpea, and pea protein ingredients for use in texturized vegetable protein (TVP) production via low moisture extrusion. The protein powders were heat-treated at temperatures ranging from 80 °C to 160 °C to modulate the extent of protein denaturation and assess their effects on RVA pasting behavior, water absorption capacity (WAC), and color attributes. The results indicate that the pretreatment temperature significantly influenced the proteins' functional properties, with an optimal temperature of 120 °C enhancing pasting properties and maintaining WAC, while a higher pretreatment temperature of 160 °C led to diminished ingredient functionality. Different protein sources exhibited distinct responses to heat pretreatment. The subsequent extrusion processing revealed significant changes in extrudate density and color, with increased density and darkness observed at higher pretreatment temperatures. This research provides insights into the interplay between protein sources, pretreatment conditions, and extrusion outcomes, highlighting the importance of controlled protein denaturation for developing high-quality, plant-based meat analogues. The findings have broad implications for the optimization of meat analogue manufacturing, with the aim of enhancing the sensory experience and sustainability of plant-based foods. [ABSTRACT FROM AUTHOR]

GdmCl and NaSCN are two strong chaotropic salts commonly used in protein folding and stability studies, but their microscopic mechanisms remain enigmatic. Here, by CD and NMR, we investigated their effects on conformations, stability, binding and backbone dynamics on ps-ns and µs-ms time scales of a 39-residue but well-folded WW4 domain at salt concentrations ≤200 mM. Up to 200 mM, both denaturants did not alter the tertiary packing of WW4, but GdmCl exerted more severe destabilization than NaSCN. Intriguingly, GdmCl had only weak binding to amide protons, while NaSCN showed extensive binding to both hydrophobic side chains and amide protons. Neither denaturant significantly affected the overall ps-ns backbone dynamics, but they distinctively altered µs-ms backbone dynamics. This study unveils that GdmCl and NaSCN destabilize a protein before the global unfolding occurs with differential binding properties and µs-ms backbone dynamics, implying the absence of a simple correlation between thermodynamic stability and backbone dynamics of WW4 at both ps-ns and µs-ms time scales. [ABSTRACT FROM AUTHOR]

Background: The background of this study revolves around Rauvolfia tetraphylla and its potential anti-inflammatory properties. To explore the anti-inflammatory activity of crude extracts obtained from the leaf and fruit of R. tetraphylla, with the goal of identifying natural compounds that could serve as safer and more effective alternatives to conventional non-steroidal anti-inflammatory drugs. Objectives: Aim of the study is to identify the most potent anti-inflammatory activity from Rauvolfia tetraphylla and optimizing the synthesis using Response Surface Methodology (RSM). The RSM analysis is to determine the influence of selected independent variables on dependent variables of the anti-inflammatory properties of R. tetraphylla, an endangered medicinal shrub. Materials and Methods: The anti-inflammatory activity of various crude extracts (hexane, chloroform, ethyl acetate and methanol) derived from the leaf and fruit of R. tetraphylla, was investigated using an in vitro assay based on denaturation of protein and utilize Response Surface Methodology to optimize the anti-inflammatory activity of the extracts using bovine serum albumin as the test protein. Results: The results showed that the ethyl acetate extract of fruit exhibited greatest inhibitory effect. Furthermore, the 3D response surface plot, perturbation plot, and contour plot were successfully obtained, indicating the interdependence of the four factors on the anti-inflammatory activity. By optimizing the parameters, it may be possible to enhance the anti-inflammatory activity, thereby maximizing the plant’s therapeutic potential. Conclusion: These findings suggest that R. tetraphylla leaf and fruit could serve as a potential source of anti-inflammatory agents with better safety and efficacy profiles compared to Non-Steroidal Anti-inflammatory Drugs. [ABSTRACT FROM AUTHOR]

This study explored the intrinsic relationship between the quality traits and protein-related property changes during the solar drying of shrimps (Penaeus vannamei). During drying, the shrimp exhibited a gradual decline in L*a*b* values and a notable increase in the hardness and chewiness. Proteins were degraded and oxidized. Especially, the trichloroacetic acid-soluble peptide and carbonyl contents increased, whereas the total sulfhydryl content decreased. The proportions of different types of intramolecular bonds were significantly changed. The ionic and hydrogen bonds greatly decreased to 10.72% and 9.05% and the hydrophobic and disulfide bonds notably increased to 19.38% and 28.19%, indicating the changes in the spatial structure of the protein and its denaturation during the drying process. The Pearson's correlation analysis showed that protein degradation and denaturation greatly affected the textural properties and protein oxidation caused color changes. The result of this work provides a theoretical support for improving the quality of shrimp products.

Drying, as a critical step in the production of air-dried beef, has a direct impact on the quality of the final product. Innovatively, a composite system incorporating contact ultrasound (CU) and infrared radiation (IR) as auxiliary measures within a hot air drying (HAD) framework was built in this research, and the effects of these techniques on the drying kinetics, protein denaturation, and moisture transformation of air-dried beef were investigated. In comparison to HAD treatment, the integrated CU and IR (CU-IRD) system displayed marked enhancements in heat and moisture transport efficiency, thereby saving 36.84% of time expenditure and contributing favorably to the improved moisture distribution of the end-product. This was mainly ascribed to the denaturation of myosin induced by IR thermal effect and the micro-channel produced by CU sponge effect, thus increasing T2 relaxation time and the proportion of free water. In conclusion, the composite system solved the problem of surface hardening and reduces hardness and chewiness of air-dried beef by 40.42% and 45.25% respectively, but inevitably increased the energy burden by 41.60%.

The influence of femtosecond laser parameters on the degree of thermal denaturation was studied experimentally. The relationship between the degree of thermal denaturation and the characteristic parameters of skin microstructure and the secondary structure of skin tissue proteins in characterizing the degree of thermal damage was analyzed. The results showed the interaction of laser power, laser power, and scanning speed had a significant effect on the degree of thermal denaturation; greater degrees of thermal denaturation were associated with larger second‐order moments of the texture angle of the skin microtissue and smaller entropy values and contrast, indicating a greater degree of thermal damage; and higher peak temperature, the lower peak intensity of Raman spectra, decrease in the percentage area of α‐helix fitted curves and increase in the percentage area of β‐sheet and β‐turn fitted curves indicate that the protein is denatured to a large extent that means thermal damage is large. [ABSTRACT FROM AUTHOR]

The plant Acalypha indica L. is a well-known traditional plant belonging to the family Euphorbiaceae. Traditional practices of the plant claim to treat asthma, pneumonia, wound healing, rheumatoid arthritis, bronchitis, and skin disorders. The major phytochemicals reported are cyanogenic glucosides, tannins, coumarins, flavonoid glycosides, fatty acids, and volatile oils. To summarize the anti-inflammatory potential of Acalypha indica extract and its phytochemicals through preclinical studies. The search terms include anti-inflammatory, Acalypha indica, and Acalypha indica extract independently or in combination with pro-inflammatory markers using various databases, including Scopus, Web of Science, PubMed, ProQuest, and Google Scholar. The results of preclinical studies confirm that Acalypha indica exhibits strong anti-inflammatory activity. Most of the experimental studies that have been conducted on plant extract are protein denaturation, human red blood cell membrane stabilization assay, and carrageenan-induced inflammation models. However, the molecular mechanism in these studies is still unclear to demonstrate its anti-inflammatory effects. Acalypha indica possesses anti-inflammatory effects that may be due to the presence of phenolic compounds especially flavonoids present in the Acalypha indica. Thus, further research is needed, to understand mechanistic insights of the plant phytochemicals to represent anti-inflammatory properties. [ABSTRACT FROM AUTHOR]

BACKGROUND: The thawing process is an essential step for a frozen marine fish. The present study aimed to investigate the effects of graphene magnetic nanoparticles combined radio-frequency thawing methods on frozen hairtail (Trichiurus lepturus) dorsal muscle. Seven thawing methods were used: air thawing, 4 °C cold storage thawing, water thawing, radio-frequency thawing (RT), radio frequency thawing combined with graphene nanoparticles (G-RT), radio frequency thawing combined with graphene oxide nanoparticles (GO-RT) and radio-frequency thawing combined with graphene magnetic nanoparticles (GM-RT). The thawing loss and centrifugal loss, electric conductivity, total volatile basic nitrogen, thiobarbituric acid reactive substances and color of thawed hairtail dorsal muscle were determined. The carbonyl content, total sulfhydryl groups, Ca2+-ATPase activity, raman spectroscopy measurements and Fourier-transform infrared spectrometry measurements were determined using myofibrillar extracted from the dorsal muscle of hairtail. The water distribution was determined using low-field NMR techniques. RESULTS: The results demonstrated that the RT, G-RT, GO-RT and GM-RT could significantly shorten the thawing time. More-over, GO-RT and GM-RT efficiently preserved the color of fish dorsal muscle and reduced the impact of thawing on fish quality by reducing lipid and protein oxidation. Meanwhile, the myofibrillar protein structure thawed by GO-RT and GM-RT were more stable and had a more stable secondary structure, which maintained strong systemic stability at the same time as slowing down protein oxidation. CONCLUSION: The results showed that GO-RT and GM-RT can significantly improve the thawing efficiency at the same time as effectively maintaining and improving the color and texture of thawed fish, slowing down the oxidation of proteins and lipids, and maintaining a good quality of thawed fish meat. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Freezing is commonly used to extend the shelf life of meat and meat products but may impact the overall quality of those products by inducing structural changes in myofibrillar proteins (MPs) through denaturation, chemical modification, and encouraging protein aggregation. This review covers the effect of freezing on the denaturation of MPs in terms of the effects of ice crystallization on solute concentrations, cold denaturation, and protein oxidation. Freezing-induced denaturation of MPs begins with ice crystallization in extracellular spaces and changes in solute concentrations in the unfrozen water fraction. At typical temperatures for freezing meat (lower than −18 °C), cold denaturation of proteins occurs, accompanied by an alteration in their secondary and tertiary structure. Moreover, the disruption of muscle cells triggers the release of cellular enzymes, accelerating protein degradation and oxidation. To minimize severe deterioration during the freezing and frozen storage of meat, there is a vital need to use an appropriate freezing temperature below the glass transition temperature and to avoid temperature fluctuations during storage to prevent recrystallization. Such an understanding of MP denaturation can be applied to determine the optimum freezing conditions for meat products with highly retained sensory, nutritional, and functional qualities. [ABSTRACT FROM AUTHOR]

Preliminary assessment for anti-inflammatory and anti-lipidemic properties was done with different solvent extracts derived from Urtica urens and Polygonum chinense leaves through in vitro experimentation. To evaluate anti-inflammatory properties, the stability of human red blood cells membranes and the denaturation activity of proteins were assessed. For anti-lipidemic effects, an assay was conducted to measure the inhibition of HMG-CoA reductase. The results of membrane stabilization showed IC50 values of 480.96 ± 0.02 and 319.41 ± 0.19 µg/mL for ethyl acetate extract of U. urens and P. chinense, respectively. The standard drug Diclofenac sodium exhibited IC50 value of 240.37 ± 0.04 µg/mL. For protein denaturation, IC50 values were determined as 221.75 ± 0.2 and 315.76 ± 0.19 µg/mL for U. urens and P. chinense, respectively. The IC50 value of the standard drug was calculated as 126.7 ± 0.34. The IC50 values towards HMG-CoA reductase inhibition were subsequently determined as 29.84 ± 0.35 µg/mL for U. urens and 24.34 ± 0.04 µg/mL for P. chinense against the standard drug Diclofenac sodium (7.52 ± 0.43 µg/mL). GC-MS chromatograms revealed the presence of bioactive compounds in ethyl acetate extract of P. chinense leaves. This work is substantiation for the traditional therapeutic utilization of these extracts.

Inflammation is a physiological process that serves as a defense mechanism for the body against foreign substances, bacteria, or irritants. Inflammation can be cured with anti-inflammatory drugs. One of the plants that has the potential to be an anti-inflammatory agent is the bamboo leaf. This research aims to analyze the content of secondary metabolites, determine the inhibition value and IC50 value of the anti-inflammatory activity of the ethanol extract of bamboo tali leaves. Bamboo tali leaves were macerated using 96% ethanol and subjected to phytochemical screening. The extract was then tested for anti-inflammatory activity in vitro with the Bovine Serum Albumin (BSA) protein denaturation inhibition method. Bamboo tali leaf ethanol extract contains flavonoids, alkaloids, saponins, and phenols. The anti-inflammatory activity of the ethanol extract of bamboo tali leaves with concentrations of 28, 42, 56, 70, and 84 ppm had an inhibition percentage value of 23.14 ± 0.008%; 34.30 0.026%; 54.51 0.060%; 69.07 ± 0.006%; and 87.02 ± 0.021% with an IC50 value of 52.991 ppm. These results indicate that the ethanol extract of bamboo tali leaves has the potential to be an anti-inflammatory with a strong IC50 value below 100 ppm.

Preliminary assessment for anti-inflammatory and anti-lipidemic properties was done with different solvent extracts derived from Urtica urens and Polygonum chinense leaves through in vitro experimentation. To evaluate anti-inflammatory properties, the stability of human red blood cells membranes and the denaturation activity of proteins were assessed. For anti-lipidemic effects, an assay was conducted to measure the inhibition of HMG-CoA reductase. The results of membrane stabilization showed IC50 values of 480.96 ± 0.02 and 319.41 ± 0.19 µg/mL for ethyl acetate extract of U. urens and P. chinense, respectively. The standard drug Diclofenac sodium exhibited IC50 value of 240.37 ± 0.04 µg/mL. For protein denaturation, IC50 values were determined as 221.75 ± 0.2 and 315.76 ± 0.19 µg/mL for U. urens and P. chinense, respectively. The IC50 value of the standard drug was calculated as 126.7 ± 0.34. The IC50 values towards HMG-CoA reductase inhibition were subsequently determined as 29.84 ± 0.35 µg/mL for U. urens and 24.34 ± 0.04 µg/mL for P. chinense against the standard drug Diclofenac sodium (7.52 ± 0.43 µg/mL). GC-MS chromatograms revealed the presence of bioactive compounds in ethyl acetate extract of P. chinense leaves. This work is substantiation for the traditional therapeutic utilization of these extracts. [ABSTRACT FROM AUTHOR]

Summary: The current study was designed to supersede the meat protein with pulse‐based proteins and to determine the suitability of the processing method for commercialisation of plant protein meat analogues. The pulse protein concentrates (PPCs) were extracted from green gram, horse gram and cowpea using alkaline/isoelectric precipitation method. The PPCs were subjected for physicochemical, morphological, GC–MS and thermal analysis. The PPCs of green gram to horse gram to cowpea were used in the ratio of (20:20:20) T1, (30:15:15) T2 and (15:20:15) T3 to prepare deep‐fried meatballs. All the PPCs exhibited collapsed and wrinkled surface. The horse gram protein concentrates exhibited the highest denaturation temperature (Td °C) 89.50 ± 2.57 and enthalpy (ΔH (J g−1)) (287.73 ± 9.64) iterating better thermal stability compared to other samples. FTIR spectra indicated the presence of O–H stretching wide bands for mutton deep‐fried meatballs (3321.22 cm−1) and plant‐based deep‐fried meatballs (3288.28 cm−1), whereas PPCs in the region of (3275–3278 cm−1). Two C‐H bands and the main secondary structural components such as α‐helix, β‐sheet, β‐turn and random coil of PPCs were observed in the region of 1600–1700 cm−1. Amide N–H bending (1400–1500 cm−1) and the C–O stretching bands (1000–1300 cm−1) were observed for all the samples. The plant‐based deep‐fried meatball formulated at the ratio of 20:20:20 (T1) was closely related to the mutton deep‐fried meatballs in terms of organoleptic properties (colour, texture, juiciness and overall acceptability), colour properties (L* and b*) and textural properties such as hardness, adhesiveness and cohesiveness. These findings will open new research horizons in this area and pave the way for the commercialisation of meat substitutes, which will reduce the environmental impact and carbon footprint. [ABSTRACT FROM AUTHOR]

The objective of this study is to determine the antiarthritic activity of the aqueous and hydroalcoholic extracts of Linum usitatissimum L. seeds in vitro, as well as the phytochemical screening and determination of the flavonoid and flavonol content in the extracts. Phytochemical analysis of Linum usitatissimum seeds revealed the presence of sterols, tannins, flavonoids, phenols, and alkaloids in the aqueous and hydroalcoholic extracts. The flavonoid contents were 06.91 ± 0.38 and 04.85 ± 0.05 mg QE/g extract for the hydroalcoholic and aqueous extracts, respectively. For the flavonol assay, the contents are 04.53 ± 0.25 mg QE/g for the hydroalcoholic extract and 04.51 ± 0.03 mg QE/g for the aqueous extract. With the Bovin Serum Albumin (BSA) test, the aqueous extract showed the protective activity against BSA denaturation significantly (P < 0.05) the highest with an IC50 of 07.62 ± 1.56 mg/ml; on the other hand, the hydroalcoholic extract of Linum usitatissimum seeds is revealed significantly (P < 0.05) the most active with the egg albumin denaturation test whose IC50 recorded is 36.86 ± 2.72 mg/ml. From the results obtained, it was found that the aqueous and hydroalcoholic extracts of Linum usitatissimum seeds possess protective activity in vitro against protein denaturation, which plays a role in the training of inflammatory and arthritic diseases. [ABSTRACT FROM AUTHOR]

Encapsulation by coacervation has received interest in the last few years because of its low cost. Ultrasound (US) processing has proven to be an adequate technology for protein denaturation, increasing coacervation yield. There is a lack of information regarding its effects on encapsulation yield. The aim of this work was to evaluate the effect of US treatments on calcium caseinate (CaCN)–kappa carrageenan (KC) coacervates and the improvements in encapsulation efficiency (EE) of ascorbic acid (AA). US‐treatments (50% and 100% amplitude, 2 and 4 min) were applied to a 2% CaCN solution. Caseinate solution was mixed with a soy oil–AA (25%) W/O emulsion to form a second emulsion W/O/W. Finally, the second emulsion was employed for complex coacervation with KC (2% solution). The results showed a 10% increase in EE in the US‐treatments, with better stability and release profiles compared to the control. Sonication proved to be effective for coacervation improvement. Practical Applications: Ultrasound pretreatment of calcium caseinate for coacervation along with kappa carrageenan showed an increase in the coacervation yield. This result was mainly attributed to the structural protein modification obtained after ultrasound (US) treatment. These coacervates can be employed to encapsulate bioactive compounds, such as ascorbic acid (AA), which is one of the most labile vitamins. In this sense, the US application leads to increases in encapsulation efficiency (around 10%) with a better stability and release profile than the capsules without treatment. These results create an opportunity to encapsulate AA and use the capsules in systems with a wide range of pH, increasing the chances of having functional products on the market. [ABSTRACT FROM AUTHOR]

• Anatase Aw-TiO 2 NPs showed a spherical shape and a size range of 3–20 nm. • Aw-TiO 2 NPs significantly decreased the viability of A375 and MCF-7 cancer cells. • Aw-TiO 2 NPs induced excessive ROS generation and decreased MMP in cancer cells. • The anti-hemolytic effects of anatase Aw-TiO 2 NPs on horse-RBCs were demonstrated. • These NPs excellently inhibited the protein denaturation. The current research reports the physicochemical and biological properties of biosynthesized titanium dioxide nanoparticles (TiO 2 NPs) using bioactive compounds of Achillea wilhelmsii C. Koch extract (Aw-TiO 2 NPs). The cytotoxic impacts of Aw-TiO 2 NPs were assessed by the MTT method on A375 and MCF-7 cancer cell lines and normal skin fibroblast cell line and also by hemolysis test against horse red blood cells (RBCs). In addition, apoptotic activity was analyzed by assaying the generation of reactive oxygen species (ROS) and reduction of mitochondrial membrane potential (MMP). Additionally, the potential of Aw-TiO 2 NPs in inhibiting protein denaturation was evaluated. The prepared Aw-TiO 2 NPs with a size range of 3–20 nm and almost spherical shape showed an anatase crystallographic phase. A significant dose-dependent reduction in cancer cell viability was observed against anatase Aw-TiO 2 NPs with IC50 values of 12.5 and 25 µg/mL for A375 and MCF-7 cells, respectively. Aw-TiO 2 NPs induced the generation of excessive ROS (95.9 %-215.4 %) and decreased MMP (60.9 %-72 %) in cancer cells, which leads to the initiation of intrinsic apoptosis. Furthermore, anatase Aw-TiO 2 NPs had no hemolytic effects on horse-RBCs and excellently inhibited protein denaturation (80.8 % at 500 µg/mL). Therefore, anatase Aw-TiO 2 NPs can be a valuable and biocompatible candidate for biomedical applications and clinical uses. [ABSTRACT FROM AUTHOR]

Summary: The cryoprotective effects of chitooligosaccharide–gallic acid (COS–GA) complexes on peeled Pacific white shrimp were investigated and compared with single treatments of COS, GA and polyphosphate (PP) during 49 days of frozen storage at −5 °C. The data revealed a significant improvement in the antioxidant activity of COS through the conjugation of COS and GA. The soaking treatments of COS–GA and PP effectively maintained the water‐holding capacity and sensory properties of shrimp muscle compared with the water‐soaked shrimp (control). Furthermore, the COS–GA‐soaked shrimp samples exhibited significant inhibitory effects on the textural and chrominance deterioration of muscle tissues compared with the control samples. Chemical analyses demonstrated that the COS–GA treatment also preserved higher levels of myofibrillar protein content, total sulfhydryl content and Ca2+‐ATPase activity in the frozen shrimp samples. Histological observations indicated that the COS–GA soaking treatment effectively protected the integrity and stability of muscle tissues. Overall, COS–GA exhibited superior antioxidation and water‐retaining properties, stabilising the shrimp muscle during long‐term frozen storage. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Molecular Science is the property of Journal of Molecular Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical chaperones are low-molecular-weight compounds that suppress protein aggregation. They can influence different stages of the aggregation process—the stage of protein denaturation, the nucleation stage and the stage of aggregate growth—and this may lead to a change in the aggregation kinetic regime. Here, the possibility of changing the kinetic regime in the presence of a chemical chaperone 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was investigated for a test system based on the thermally induced aggregation of yeast alcohol dehydrogenase (yADH) at 56 °C. According to differential scanning calorimetry data, 2-HP-β-CD did not affect the stage of the protein molecule unfolding. Dynamic light scattering data indicated changes in the aggregation kinetics of yADH during the nucleation and aggregate growth stages in the presence of the chaperone. The analysis of kinetic curves showed that the order of aggregation with respect to protein (nc), calculated for the stage of aggregate growth, changed from nc = 1 to nc = 2 with the addition of 100 mM 2-HP-β-CD. The mechanism of 2-HP-β-CD action on the yADH thermal aggregation leading to a change in its kinetic regime of aggregation is discussed. [ABSTRACT FROM AUTHOR]

Protein denaturation during spray drying is critical for high-quality food powders. This study investigated the influence of particle size on protein denaturation using phycocyanin as a marker. The effect of particle size was investigated at three different air outlet temperatures, with the inlet air temperature held constant. For each temperature combination, different nozzles were utilized to obtain varying particle sizes. Denaturation increased with higher outlet air temperature and larger particle size, up to a size of 40 μm. This increase in denaturation with particle size was attributed to faster drying rates and the absence of denaturation once particles are dry. Particle size had a similar magnitude of effect as outlet air temperature. For larger particles, a plateau in denaturation was observed due to a prolonged constant drying rate regime. It can be assumed that conditions that retain phycocyanin are also suited for the retention for less thermolabile proteins. [ABSTRACT FROM AUTHOR]

Indirect immunofluorescence is usually restricted to 3-5 markers per preparation, limiting analysis of coexistence. A solution containing 2-mercaptoethanol and sodium dodecyl sulfate (2-ME/SDS) can elute indirect immunofluorescence labelling (i.e. primary antisera followed by fluorophore-conjugated secondary antisera) and has been used for sequential staining of sections. The aim of this study was to test whether 2-ME/SDS is effective for eluting indirect immunofluorescent staining (with primary antisera visualised by fluorophore-coupled secondary antisera) in wholemount preparations. We also analysed how 2-ME/SDS may work and used this understanding to devise additional uses for immunofluorescence in the nervous system. 2-ME/SDS appears to denature unfixed proteins (including antisera used as reagents) but has much less effect on antigenicity of formaldehyde-fixed epitopes. Moieties linked by strong biotin-streptavidin bonds are highly resistant to elution by 2-ME/SDS. Two primary antisera raised in the same species can be applied without spurious cross-reactivity, if a specific order of labelling is followed. The first primary antiserum is followed by a biotinylated secondary, then a tertiary of fluorophore-conjugated streptavidin. The preparation is then exposed to 2-ME/SDS, which has minimal impact on labelling by the first primary/secondary/tertiary combination. However, when this is followed by a second primary antiserum (raised in the same species), followed by a fluorophore-conjugated secondary antiserum, the intervening 2-ME/SDS exposure prevents cross-reactivity between primary and secondary antisera of the two layers. A third property of 2-ME/SDS is that it reduces lipofuscin autofluorescence, although it also raises background fluorescence and strongly enhances autofluorescence of erythrocytes. In summary, 2-ME/SDS is easy to use, cost-effective and does not require modified primary antisera. It can be used as the basis of a multi-layer immunohistochemistry protocol and allows 2 primary antisera raised in the same species to be used together.

Background: Capparis cartilaginea Decne.(C. cartilaginea Decne.) a medicinally important plant that belongs to the family Capparaceae. Traditionally the fruit, leaf, and root have been believed to show anti-inflammatory effects and can also be used as agents. Purpose: The objective of this study is to investigate the chemical compositions, in-vitro antioxidant, anti-cancer and anti-inflammatory activities of the ethanolic extract of Capparis cartilaginea Decne. leaves. Study methods: The chemical compounds were investigated by Gas Chromatography–Mass Spectrometry (GC–MS) analysis. Ferric-bipyridine reducing capacity of total antioxidants (FBRC), Ferric reducing antioxidant power (FRAP) were utilized to determine antioxidant activity. The cytotoxic activity was evaluated using a 3-[4,5-dimethylthiazole- 2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. Additionally, in vitro anti-inflammatory activity of the ethanolic extract of C. cartilaginea Decne. leaves using COX1 and protein denaturation methods. Results: The major twenty- four bioactive compounds from fifty compounds were identified including alkaloids, flavonoids, phenols, fatty acids, and carotenes. Pleiocarpamine was the major constituent of the extract (73.07 %). Additionally, in vitro anti-inflammatory activity of the ethanolic extract of C. cartilaginea Decne. leaves using COX1 and protein denaturation methods showed a strong effect with IC50 values of 60.23 and 17.67 µg/mL respectively, compared to Indomethacin and Diclofenac as a standard anti-inflammatory drug.; while FBRC and FRAP were utilized to determine antioxidant activity slowed high antioxidants capacity with values 0.056 ± 0.001and 0.03 ± 0.00196 Ascorbic acid equivalent/g of extract (AAE) and DPPH radical scavenging method show IC50 value 10 ± 1 %. Evaluation of the cytotoxic activity against three human cancer cell lines colon carcinoma cells HCT-116, Breast carcinoma cells MCF-7, and human muscle Rhabdomyosarcoma RD cell line using MTT assay showed a significant effect with IC50 values 59.58 ± 1.5, 39.14 ± 3.09, and 102 ± 8.75 µg/mL, compared to Vinblastine Sulfate as a standard cytotoxic drug. Yemeni C. cartilaginea Decne. showed a higher effect on MCF-7 compared to Iranian C. cartilaginea Decne. as well as established a higher antioxidant activity than that extracts obtained from Jordan. Conclusion: Ethanolic leaves extract of C. cartilaginea Decne. have the potential for development as therapeutic agents for cytotoxicity on certain cancer cells following further investigation. C. cartilaginea Decne. leaves that could have medicinal values and application in industries, were used to design the drug for the treatment of various types of inflammatory diseases.

In order to investigate the intrinsic relationship between protein characteristics and quality changes during the hot air drying of shrimp, Penaeus vannamei was dried by hot air at 55 ℃ after being boiled in 3% salt solution for 2 minutes. We studied changes in the microstructure and quality of shrimp, and systematically investigated changes in the oxidative degradation degree, intramolecular valence bonds, and secondary and tertiary structure of protein. The results showed that the drying treatment gradually decreased the L*, a* and b* values of shrimp, and changed the texture characteristics, and the hardness, adhesiveness and chewiness were increased to 344.78 N, 45.01 mJ and 116.50 mJ at the end of drying, respectively. In addition, oxidative denaturation and degradation of proteins occurred; the total sulfhydryl content decreased to 0.36 μmol/g at the end of drying, while the carbonyl content increased to 2.03 nmol/mg protein, and the trichloroacetic acid (TCA)-soluble peptide content increased to 0.91 μmol/g. The protein structure was significantly changed; the relative contents of ionic and hydrogen bonds decreased, the relative contents of hydrophobic and disulfide bonds increased, the secondary structure was transformed from α-helix to β-fold, β-turn and random coil, the intensity of tryptophan fluorescence decreased, and the tertiary structure was also changed. Pearson correlation analysis showed that the color changes were mainly related to protein oxidation and protein degradation and denaturation significantly affected the textural properties of shrimp. This study can provide theoretical support for further improving the quality of dried shrimp products.

Defining the denatured state ensemble (DSE) and disordered proteins is essential to understanding folding, chaperone action, degradation, and translocation. As compared with water-soluble proteins, the DSE of membrane proteins is much less characterized. Here, we measure the DSE of the helical membrane protein GlpG of Escherichia coli (E. coli) in native-like lipid bilayers. The DSE was obtained using our steric trapping method, which couples denaturation of doubly biotinylated GlpG to binding of two streptavidin molecules. The helices and loops are probed using limited proteolysis and mass spectrometry, while the dimensions are determined using our paramagnetic biotin derivative and double electron-electron resonance spectroscopy. These data, along with our Upside simulations, identify the DSE as being highly dynamic, involving the topology changes and unfolding of some of the transmembrane (TM) helices. The DSE is expanded relative to the native state but only to 15 to 75% of the fully expanded condition. The degree of expansion depends on the local protein packing and the lipid composition. E. coli's lipid bilayer promotes the association of TM helices in the DSE and, probably in general, facilitates interhelical interactions. This tendency may be the outcome of a general lipophobic effect of proteins within the cell membranes.

The interactions of proteins with surfaces are important in both biological processes and biotechnologies. In contrast to decades of study regarding the biophysics of proteins in bulk solution, however, our mechanistic understanding of the biophysics of proteins interacting with surfaces remains largely qualitative. In response, we have set to explore quantitatively the thermodynamics of protein-surface interactions. In this work, we explore systematically the role of electrostatics in modulating the interaction between proteins and charged surfaces. In particular, we use electrochemistry to explore the extent to which a macroscopic, hydroxyl-coated surface held at a slightly negative potential affects the folding thermodynamics of surface-attached protein variants with different composition of charged amino acids. Doing so, we find that attachment to the surface generally leads to a net stabilization, presumably due to excluded volume effects that reduce the entropy of the unfolded state. The magnitude of this stabilization, however, is strongly correlated with the charged-residue content of the protein. In particular, we find statistically significant correlations with both the net charge of the protein, with greater negative charge leading to less stabilization by the surface, and with the number of arginines, with more arginines leading to greater stabilization. Such findings refine our understanding of protein-surface interactions, providing in turn a guiding rationale to achieve the functional deposition of proteins on artificial surfaces for implementation in, for example, protein-based biotechnologies.

Turmeric rhizomes (Curcuma longa) and black cumin seeds (Nigella sativa) are polyherbal ingredients used for the management of cancer and other chronic inflammatory diseases in Nigerian ethnomedicine. Previous studies have shown the antioxidant, anti-inflammatory, and anticancer activities of the individual plant extracts. However, the two spices have not been biologically potentiated in their combined form. Therefore, this study obtained essential oils (EOs) from the combined spices and evaluated their inhibitory effects on free radicals, protein denaturation, and cancer proliferation. The EOs were extracted by hydro-distillation (HD) and characterized by gas chromatography-mass spectrometry (GC-MS). In vitro antioxidant assessment was conducted based on DPPH, hydrogen peroxide (H2O2), nitric oxide (NO), and ferric ion (Fe3+) radical scavenging assays. The cytotoxicity of the oil against non-tumorigenic (HEK293) and cancerous (HepG2 and HeLa) cell lines was determined following the MTT cell viability assay. An in silico molecular docking analysis of the oil constituents was also performed. Six batches of EOs I–VI were afforded, comprising twenty-two major constituents, with aromatic Ar-turmerone being the most prominent compound. There was a marked improvement in the bioactivity of the oils upon repeated HD and as a combination. The batch VI oil exhibited the best activity, with a cytotoxicity (CC50) of 10.16 ± 1.69 µg/100 µL against the HepG2 cell line, which was comparable to 5-fluorouracil (standard, CC50 = 8.59 ± 1.33 µg/100 µL). In silico molecular docking suggested δ-curcumene, Ar-curcumene, Ar-turmerol, and Ar-turmerone among the promising compounds based on their high binding energy scores with NOX2, NF-κB, and mdm2 proteins. In conclusion, the oils from the turmeric–black cumin combined possess a considerable inhibition ability against free radicals, protein denaturation, and cancer proliferation. This study’s findings further underscore the effectiveness of turmeric–black cumin as a polyherbal medicinal ingredient.

This study investigates the impact of dry heat pretreatment on the functionality of soy, chickpea, and pea protein ingredients for use in texturized vegetable protein (TVP) production via low moisture extrusion. The protein powders were heat-treated at temperatures ranging from 80 °C to 160 °C to modulate the extent of protein denaturation and assess their effects on RVA pasting behavior, water absorption capacity (WAC), and color attributes. The results indicate that the pretreatment temperature significantly influenced the proteins’ functional properties, with an optimal temperature of 120 °C enhancing pasting properties and maintaining WAC, while a higher pretreatment temperature of 160 °C led to diminished ingredient functionality. Different protein sources exhibited distinct responses to heat pretreatment. The subsequent extrusion processing revealed significant changes in extrudate density and color, with increased density and darkness observed at higher pretreatment temperatures. This research provides insights into the interplay between protein sources, pretreatment conditions, and extrusion outcomes, highlighting the importance of controlled protein denaturation for developing high-quality, plant-based meat analogues. The findings have broad implications for the optimization of meat analogue manufacturing, with the aim of enhancing the sensory experience and sustainability of plant-based foods.

GdmCl and NaSCN are two strong chaotropic salts commonly used in protein folding and stability studies, but their microscopic mechanisms remain enigmatic. Here, by CD and NMR, we investigated their effects on conformations, stability, binding and backbone dynamics on ps-ns and µs-ms time scales of a 39-residue but well-folded WW4 domain at salt concentrations ≤200 mM. Up to 200 mM, both denaturants did not alter the tertiary packing of WW4, but GdmCl exerted more severe destabilization than NaSCN. Intriguingly, GdmCl had only weak binding to amide protons, while NaSCN showed extensive binding to both hydrophobic side chains and amide protons. Neither denaturant significantly affected the overall ps-ns backbone dynamics, but they distinctively altered µs-ms backbone dynamics. This study unveils that GdmCl and NaSCN destabilize a protein before the global unfolding occurs with differential binding properties and µs-ms backbone dynamics, implying the absence of a simple correlation between thermodynamic stability and backbone dynamics of WW4 at both ps-ns and µs-ms time scales.

Aquatic animal products are rich in protein, lipids, and moisture and are often stored at frozen temperature. However, aquatic animal products are prone to deterioration caused by ice crystal formation, lipid oxidation and protein denaturation. Quick freezing is crucial for preserving the quality of aquatic animal products by preventing the formation of large ice crystals. Liquid nitrogen quick-freezing (LNF) provides a fast-freezing rate, minimal ice crystal formation, preservation of product texture and nutritional properties, shelf-life extension, energy efficiency, and quality and safety improving. This review comprehensively illustrates the mechanism of LNF, the impact of LNF on qualities of aquatic animal products including flavor, texture, color, and nutrition. Additionally, LNF devices applied on aquatic animal products are also discussed. Furthermore, future prospects and research directions are suggested, including optimizing freezing processes, understanding the impact on nutritional value and considering sustainability and energy consumption. However, challenges such as freezing damage, cost considerations, and quality control issues for LNF application need to be addressed.

The water distribution have a profound influence on meat quality, and proteins play a critical role in water distribution. The water distribution detected with proton NMR and its relationship with protein related properties were investigated. Three populations of water were detected: bound water (T21, P21), immobilized water (T22, P22), and free water (T23, P23). The decreased T22 and T23 indicated an increase in water-holding capacity in both muscles from 3 days of aging. The P22 in cattle was higher than that in yak and the P23 in cattle was lower than that in yak, suggesting that cattle exhibited a greater water-holding capacity compared to yak. Moreover, postmortem aging affected muscle protein oxidation, denaturation, and degradation. Correlation analysis suggested that protein oxidation and denaturation caused muscle water loss and protein degradation could allow the muscle to retain water. It provides a basis for the optimization of quality of meat and products.

Background: Rheumatoid arthritis (RA) is an inflammation of joints with increased cellularity of synovial tissue. Allopathic drugs possess several adverse effects, which have led to increase in the utilization of herbal medicines. Polyherbal emulgel resolves the bioavailability issue associated with hydrophobic drugs and can be used effectively in the treatment of RA. Objectives: The present study aimed at the formulation of polyherbal emulgel, and evaluation of in vitro anti-inflammatory activity and in vivo antiarthritic activity. Methods: Seven emulgels F-1 to F-7 were optimally formulated. In vitro anti-inflammatory activity was determined using protein denaturation method employing Diclofenac sodium as the standard. In antiarthritic study Complete Freund's Adjuvant (CFA) model was used. The various parameters were assessed, like paw volume, body weight, hematological parameters, antioxidant parameters, Rheumatic factor (RF), and histopathological study of ankle joint. Results: F-4 and F-7 were found to be optimized formulations as compared to other formulations. The in vitro anti-inflammatory activity was found to be highest in F-4 with IC50 7.74 and F-7 with IC50 8.87 in comparison with Diclofenac sodium having IC50 57.0. Both formulations F-7 and F-4 showed a significant reduction in paw volume and normalization of body weights. The formulation F-7 even showed more potent antiarthritic activity than F-4 by decreasing white blood cells (WBC), lymphocytes, increasing packed cell volume (PCV), neutrophils, superoxide dismutase (SOD), catalase and decreasing malondialdehyde (MDA) levels in serum. This was further confirmed by histopathological study. Conclusion: As an anti-inflammatory agent, this newly developed emulgel was found to possess more therapeutic efficacy than commercially available diclofenac sodium.

We present a mathematical model for the full drying process of a single protein formulation droplet taking into account the convective impact arising from its levitation by a standing ultrasound wave. Using the finite element method allows us to compute the evaporation rate directly from the fully resolved heat and mass transfer within and around the levitated droplet. We apply our model to simulate the drying kinetics of pure water and aqueous phosphoglycerate kinase (PGK) droplets under various levitation and drying conditions. Empirical data from the literature are used to validate and discuss our numerical results. The acoustic streaming turns out to accelerate not only the first but also the second drying stage. Moreover, the dehydration of the protein molecules is found to be primarily responsible for their enzymatic inactivation throughout the drying process. [ABSTRACT FROM AUTHOR]

Protein denaturation is a common process in the food industry, which can impact food quality and safety. Computational Fluid Dynamics (CFD) is a powerful tool that can be used to predict protein denaturation in food products. In this review article, we present an overview of the application of CFD simulation in predicting protein denaturation in food products. We discuss the factors that influence protein denaturation, the importance of predicting protein denaturation, and the various numerical methods used in protein denaturation studies. The main focus of the article is the use of CFD simulation in predicting protein denaturation in selected food products, such as milk, meat, and eggs. We provide examples of numerical studies that have been conducted on these products, and we discuss the results and implications of these studies. The use of CFD simulation can help to optimize food processing conditions, improve food quality and safety, and reduce waste and costs in the food industry. Overall, this review article highlights the importance of using advanced computational tools such as CFD simulation in food science, research and development. The use of CFD simulation can predict protein denaturation in food products. Numerical studies were conducted on selected food products to analyze protein denaturation. CFD simulation provides a powerful tool for optimizing food processing technologies. The results from the numerical studies can be used to improve the quality and safety of food products. The application of CFD simulation can lead to more efficient and sustainable food production practices. [ABSTRACT FROM AUTHOR]

Serum autoantibody profiles are unique to individuals and reflect the level and history of autoimmunity and tumor immunity. The identification of autoantibody biomarkers is critical for the development of immune monitoring systems for immune‐related disorders. Here, we present a practical method for large‐scale autoantibody discovery using total cellular proteins from cultured mammalian cells. We found that nucleic acid‐free and fully denatured water‐soluble total cellular proteins from mammalian cells were superior, allowing precise separation by reversed‐phase HPLC after preparing a large set of homogeneous total cellular proteins. After separating the proteins based on hydrophobicity, the fractionated samples were subjected to molecular mass analysis using conventional SDS‐PAGE. The resulting two‐dimensional gel electrophoresis was successfully employed for immune blotting and LC–MS/MS analysis. All procedures, including TRIzol‐based total cellular protein extraction, solubilization of denatured proteins, reversed‐phase HPLC separation, and SDS‐PAGE, were highly reproducible and easily scalable. We propose this novel two‐dimensional gel electrophoresis system as an alternative proteomics‐based methodology suitable for large‐scale autoantibody discovery. [ABSTRACT FROM AUTHOR]

Nickel, an important transition metal element, is one of the trace elements for human body and has a crucial impact on life and health. Some evidences show the excess exposure to metal ions might be associated with neurological diseases. Herein, we applied Raman spectroscopy to study the Ni(II) ion effect on kinetics of amyloid fibrillation of hen egg white lysozyme (HEWL) in thermal and acidic conditions. Using the well-known Raman indicators for protein tertiary and secondary structures, we monitored and analyzed the concentration effect of Ni(II) ions on the unfolding of tertiary structures and the transformation of secondary structures. The experimental evidence validates the accelerator role of the metal ion in the kinetics. Notably, the additional analysis of the amide I band profile, combined with thioflavin-T fluorescence assays, clearly indicates the inhibitory effect of Ni(II) ions on the formation of amyloid fibrils with organized β-sheets structures. Instead, a more significant promotion influence is affirmed on the assembly into other aggregates with disordered structures. The present results provide rich information about the specific metal-mediated protein fibrillation. [ABSTRACT FROM AUTHOR]

This study was conducted on chicken pectoralis major muscle with different wooden breast severity in combination with different sampling locations to investigate the effects of wooden breast syndrome on protein traits and total myofiber area, and their associations. Contents of sarcoplasmic, salt-soluble myofibrillar and salt-insoluble protein and proportion of total myofiber area significantly declined with increasing severity in the superficial part of muscle, whereas the amount of heat-soluble/insoluble collagen and protein denaturation as well as the area of degenerated myofibers, connective tissue and cellular infiltrates increased. Myofibril protein content indicators showed strong positive correlations to total myofiber area. Moreover, PCA results indicated that severe wooden breast is positively linked to muscle collagen content and to protein denaturation. Our results suggest that decrease in sarcoplasmic and myofibrillar proteins is associated with reduction of myofiber area. In turn, the muscle fibers are replaced by connective tissue, accompanied by excessive myofibrillar and sarcoplasmic protein denaturation. [ABSTRACT FROM AUTHOR]

The vanilloid receptor TRPV1 is an exquisite nociceptive sensor of noxious heat, but its temperature-sensing mechanism is yet to define. Thermodynamics dictate that this channel must undergo an unusually energetic allosteric transition. Thus, it is of fundamental importance to measure directly the energetics of this transition in order to properly decipher its temperature-sensing mechanism. Previously, using submillisecond temperature jumps and patch-clamp recording, we estimated that the heat activation for TRPV1 opening incurs an enthalpy change on the order of 100 kcal/mol. Although this energy is on a scale unparalleled by other known biological receptors, the generally imperfect allosteric coupling in proteins implies that the actual amount of heat uptake driving the TRPV1 transition could be much larger. In this paper, we apply differential scanning calorimetry to directly monitor the heat flow in TRPV1 that accompanies its temperature-induced conformational transition. Our measurements show that heat invokes robust, complex thermal transitions in TRPV1 that include both channel opening and a partial protein unfolding transition and that these two processes are inherently coupled. Our findings support that irreversible protein unfolding, which is generally thought to be destructive to physiological function, is essential to TRPV1 thermal transduction and, possibly, to other strongly temperature-dependent processes in biology [ABSTRACT FROM AUTHOR]