Increase In Disulfide Research Articles

Relação entre estresse oxidativo e COVID-19: uma breve revisão sistemática

OBJECTIVE: Analyse the possible relationship between Oxidative Stress (OS) and the pathogenesis of COVID-19. METHODS: This brief systematic literature review was conducted based on the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The search resulted in the selection of 10 papers that met the research theme and were published between January 2020 and March 2021. RESULTS: The results revealed that in the course of the disease, there is a decrease in thiol levels and an increase in disulfide and EO, with a probable depletion of antioxidant elements. They found that the accumulation of Reactive Oxygen Species (ROS), added to the damage to albumin, were related to a worse prognosis and that neutrophils may be responsible for the increased level of oxidative stress associated with the worsening of the clinical condition. In addition, cells transfected with the SARS-CoV-2 spike protein showed around three times the concentration of ROS compared to non-transfected control cells. As for serum O2- levels, they were significantly elevated in critically ill patients, constituting a probable predictor of disease severity. CONCLUSIONS: Thus, from the findings of this study, it is possible to infer that both patients with severe and moderate forms of COVID-19 have high EO index values. However, further studies need to be carried out to confirm these preliminary results.

3D printing of prawn mimics with faba proteins: The effects of transglutaminase and curdlan gum on texture

With its capability for automated production of high-resolution structures, 3D printing can develop plant-based seafood mimics with comparable protein content. However, the challenge lies in solidifying 3D printed products to achieve the firmness of seafood. Targeting prawn, texturisation of its 3D printed mimic by curdlan gum was compared against incubation with a protein cross-linking enzyme, microbial transglutaminase. Faba bean protein extract (FBP) was selected for its lightest colour. To confer structural stability to the FBP-based ink without hindering extrudability, adding 1 % xanthan gum was optimal. Printed curdlan-containing mimics were steamed for 9 min, while printed transglutaminase-containing mimics were incubated at 55 °C before steaming. Either adding 0.0625 % or 0.125 % w/w curdlan or, incubating the transglutaminase-containing mimics for an hour achieved chewiness of 818.8–940.6 g, comparable to that of steamed prawn (953.13 g). Curdlan hydrogel penetrated and reinforced the FBP network as observed under confocal imaging. Whereas incubation of transglutaminase-containing mimics enhanced microstructural connectivity, attributable to transglutaminase-catalysed isopeptide cross-linkages, and the consequent increase in disulfide bonding and β-sheet. Ultimately, transglutaminase treatment appeared more suitable than curdlan, as it yielded mimics with cutting strength comparable to steamed prawn. Both demonstrated promising potential to broaden the variety of 3D printed seafood mimics.

Investigating the physicochemical properties and air-water interface adsorption behavior of transglutaminase-crosslinking rapeseed protein isolate

Improving the technical functionality to adapt to the application of complex food systems is an important challenge for the development of plant protein ingredients. Herein, the correlation between the physicochemical properties and interfacial adsorption behavior of rapeseed protein isolate (RPI) at the air–water interface after transglutaminase (TG) treatment was investigated. The results of cross-linking degree, Fourier transform infrared spectroscopy (FTIR) and sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE) showed that the TG enzyme was able to catalyse cross-linking between lysine and glutamine residues of RPI. The foaming capacity of RPI was enhanced from 120 % to 150 % after TG cross-linking 5 h, whereas the average size (210–219 nm) of the RPI determined by dynamic light scattering did not change significantly. Besides, the hydrophobicity tended to increase overall under the enzyme treatment, while the surface electrostatic potential decreased. The former indicates the unfolding of the protein and reduces the kinetic barriers to protein adsorption at the air–water interface, with a consequent increase in disulfide bonding and surface pressure. Furthermore, as the enzyme treatment time increased, a significant increase in protein content of foam by 33.86 %. These findings provide novel insight into the foaming mechanism of TG cross-linking RPI.

Diz Replasmanı Ameliyatı Altındaki Hastalarda Bacağın İskemi/Reperfüzyonu Sırasında Tiyol-Disülfit Dengesi Üzerine Spinal ve Genel Anestezinin Etkisi

Objective: Surgical trauma causes serious neuroendocrine and cytokine activity. In addition, the free oxygen radicals formed because of the ischemia/reperfusion injury resulting from applying and releasing the tourniquet (TQ) cause oxidative stress. Thiol and disulfide are among the new oxidative stress parameters used reliably in recent years. The aim of this study was to compare thiol-disulfide balance in general and spinal anesthesia, which are frequently used in total knee replacement (TKR) surgery. Methods: Fifty six patients aged 60-74 years scheduled to undergo TKR were randomly allocated to the general anesthesia (n=26) and spinal anesthesia (n=30) groups. The tourniquet (TQ) was applied for the TKR procedure after collecting a preanesthetic blood sample (T1). Blood samples were also collected at 5 minutes (T2) and 40 minutes (T3) after TQ release and at postoperative 24 hours (T4) to analyze native thiol, total thiol, disulfide, disulfide/native thiol ratio, disulfide/total thiol ratio, and native thiol/total thiol ratio. All patients had intravenous patient-controlled analgesia during the postoperative period. Mean arterial pressure, TQ times, and Visual Analogue Scale (VAS) scores were recorded. Decrease in thiol and increase in disulfide in the thiol-disulfide balance were recorded as oxidative stress indicators. Results: There was no difference between the groups in terms of VAS and analgesic consumption at the end of 24 hours. The general anesthesia group had higher native thiol, total thiol, and native thiol/total thiol ratio and lower disulfide, disulfide/native thiol ratio, and disulfide/total thiol ratio at all time points compared to the spinal anesthesia group. Conclusion: Assessment in terms of thiol-disulfide balance suggests that general anesthesia had a favorable effect on oxidative stress. Keywords: General anesthesia, oxidative stress, spinal anesthesia, thiol-disulfide, tourniquet time, visual analogue scale

Numerical investigation of thermal radiation impact on gold–molybdenum disulfide/water hybrid nanofluids with convective condition

This analysis evaluates the characteristics of conventional nanofluid heat transfer with those of emerging hybrid nanofluid. Hybrid nanofluid, a new type of conventional fluid, has been used toward the enhancement of heat transfer in the boundary layer flow. This research also prompts that 0.001 solid volume fraction of Gold (Au) is fixed, then consequently, various solid volume fractions of Molybdenum disulfide (Mo) are added into the mixture with water as the base fluid to form Au - Mo/water hybrid nanofluid. Using the necessary similarity variables, the governing non-linear partial differential equations are resolved into a system of coupled ordinary non-linear differential equations. The transformed equations are numerically solved by employing the Runge-Kutta Fehlberg method with shooting technique. The numerical parametric analysis, which has been conducted to explore the effects of different physical parameters involved in the problem, provides comparisons. The present problem is new, original, with many substantial findings in the current industry for practical problems. It is found that dual solutions exist up to a certain value of the decreases as nanoparticle volume fractions for Molybdenum disulfide increase.

Is There A Relationship Between The Umbilical Cord Coiling Index And Oxidative Stress Markers And SGA Fetuses?

Objective: We aimed to investigate the relationship between umblical coiling index and thiol/disulfide balance in SGA newborns to compare with AGA newborns.
 Material and Methods: Fetal umbilical cord serum samples were collected during labour and the thiol/disulfide homeostasis was measured. After birth, umbilical cords were collected and cord parameters were examined including, length, number of coils, umbilical cord index.
 Results: Significant decrease in native thiol, total thiol, and a significant increase in disulfide, disulfide/native thiol ratio and disulfide/total thiol ratios were observed in the study group while native thiol/total thiol ratio levels of the two groups did not reach to a statistical significance.
 Conclusion: The results of this study showed that SGA babies had altered thiol homeostasis in favor of oxidative stress.

Influence of Cooking Conditions on the Protein Matrix of Sorghum and Maize Endosperm Flours

ABSTRACTTo understand the influence of the sorghum and maize endosperm protein matrix honeycomb structure on starch hydrolysis in flours, three‐dimensional fluorescence microscopy was applied to floury and vitreous endosperm flours cooked under various conditions. Cooking caused the collapse and matting of the sorghum and maize vitreous endosperm matrices, with the effect being greater in sorghum. The effect of cooking was rather different in the floury endosperm in that the protein matrices expanded and broke up to some extent. These effects were a consequence of expansion of the starch granules through water uptake during gelatinization. Cooking in the presence of 2‐mercaptoethanol caused an expansion of the vitreous endosperm matrix mesh due to breakage of disulfide bonds in the protein matrix. Mercaptoethanol also caused an increase in the proportion of β‐sheet structure relative to α‐helical structure of the endosperm proteins. Increased energy of cooking caused collapse of the sorghum matrix. Disulfide bonding and an increase in β‐sheet structure occurred with cooking, with the increase in disulfide bonding being greatest in sorghum vitreous endosperm. The tendency for the sorghum protein matrix to collapse and mat more with cooking than the maize matrix appears to be due to greater disulfide bonding. This is responsible for the observed low starch digestibility of cooked sorghum flour as a result of the more disulfide‐bonded protein matrix limiting the expansion of the starch granules and hence amylase access.

Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Our laboratory treats guinea pigs with hyperbaric oxygen (HBO) as a model for investigating the formation of nuclear cataract. Previous analyses of lens supernatants using this model have shown an increase in disulfide (–SS–) and loss of sulfhydryl (–SH) in the lens nucleus of O 2-treated animals. In this paper, we have used the non-invasive technique of Raman spectroscopy to confirm these findings in intact, freshly-excised lenses. Guinea pigs were treated 3 times per week with HBO for a total of 50 (4 months of treatment) or 85 (7 months of treatment) times to induce an increased level of lens nuclear light scattering. Intact lenses were analyzed by Raman spectroscopy using a 514.5 nm laser and collecting the scattered light in a 90° geometry. The laser beam was focused either in the lens nucleus or equatorial cortex. Changes in the levels of –SS– (503 cm −1) and –SH (2577 cm −1) vibrations were measured. Raman spectra were analyzed by fitting Lorentzian profiles to the observed data in the –SS– and –SH regions. –SS– levels in the O 2-treated nucleus were found to have increased by a factor of 2.1 ( p = 0.0001) and 2.5 ( p = 0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. Based on previous biochemical analyses, the –SS– increase was due mainly to the formation of protein disulfide (PSSP) with contribution also from protein/thiol mixed disulfides, but not from oxidized glutathione. –SH levels in the O 2-treated nucleus decreased by 13% ( p = 0.007) and 35% ( p = 0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. No significant increase in –SS– or loss of –SH was observed in the lens cortex of the O 2-treated guinea pigs. The Raman spectroscopy results rule out the possibility that artifactual production of –SS– and loss of –SH occurred during homogenization of lenses in previous studies. The data provide additional evidence to support a link between O 2, disulfide-crosslinking of lens crystallins in the nucleus, and nuclear cataract.

A histochemical study of the keratotic process in oral lesions diagnosed clinically as leukoplakia

The keratotic process was studied microscopically and histochemically in eighty oral lesions diagnosed clinically as leukoplakia. In all lesions the stratum corneum was thickened and presented varied degrees of hyperkeratosis or parakeratosis, separately or in combination. Several histochemical differences between the hyperkeratotic and parakeratotic lesions were noted. Of particular interest was the observation that hyperkeratotic lesions were characterized by an increase in disulfides and a diminution in sulfhydryls in the stratum corneum which did not occur in parakeratotic lesions. An intermittent type of keratosis was also described.