scholarly journals Lutein and Zeaxanthin in the Lipid Bilayer–Similarities and Differences Revealed by Computational Studies

2021 ◽  
Vol 8 ◽  
Author(s):  
Krzysztof Makuch ◽  
Jakub Hryc ◽  
Michal Markiewicz ◽  
Marta Pasenkiewicz-Gierula
Keyword(s):  
Lipid Bilayer ◽  
Chemical Structure ◽  
Molecular Level ◽  
Computer Modelling ◽  
Horizontal Orientation ◽  
Ring Rotation ◽  
Essential Components ◽  
Modelling Studies ◽  
The Difference ◽  
And Oxidative Stress

Lutein and zeaxanthin are two similar carotenoids of the xanthophyll subgroup. Carotenoids are synthesized almost entirely by plants but are also present in significant amounts in animals. They are essential components of the lipid matrix of biomembranes, and one of their functions is to protect cells from light radiation, free radicals and oxidative stress. Carotenoids, depending on their chemical structure, can locate at various positions and in different orientations in the bilayer. Xanthophylls (XAN) are polar and in the bilayer are positionally restricted. In the case of lutein and zeaxanthin, whose both ionone rings are hydroxy-substituted and as such are anchored in the lipid bilayer interfaces, the position is generally transmembrane. However, both experimental and computer modelling studies indicate that lutein can also locate horizontally below the bilayer interface. This location has never been observed for zeaxanthin. To find a molecular-level explanation for the difference in the orientations of the XAN molecules in the bilayer, a number of phosphatidylcholine-XAN bilayers were constructed and molecular dynamics (MD) simulated for 1.1 µs each. The all-trans XAN molecules were initially placed either parallel or perpendicular to the bilayer surface. With the exception of one lutein, the horizontally placed molecules adopted the transmembrane orientation within 100–600 ns. On the basis of detailed analyses of the XAN orientations and the numbers and lifetimes of their interactions in the bilayer, a plausible explanation is offered as to why a lutein molecule may remain in the horizontal orientation while zeaxanthin does not. Contrary to common believe, lutein horizontal orientation is not related to the ε-ring rotation around the C6′-C7′ bond.

scholarly journals Condensed phase properties of n-pentadecane emerging from application of biomolecular force fields

2020 ◽  
Author(s):  
Maciej Bratek ◽  
Anna Wójcik-Augustyn ◽  
Adrian Kania ◽  
Jan Majta ◽  
Krzysztof Murzyn
Keyword(s):  
Force Field ◽  
Condensed Phase ◽  
Chemical Structure ◽  
Computer Modelling ◽  
Hydrocarbon Chains ◽  
Linear Alkanes ◽  
Molecular Modelling Studies ◽  
Modelling Studies ◽  
Force Field Parameters ◽  
Phase Properties

For over 20 years, the OPLS-All Atom (OPLS-AA) force field has been efficiently used in molecular modelling studies of proteins, carbohydrates and nucleic acids. OPLS-AA is successfully applied in computer modelling of many organic compounds, including decane and shorter alkanes, but it fails when employed for longer linear alkanes, whose chemical structure corresponds to hydrocarbon tails in phospholipids constituting cellular membranes. There have been several attempts to address this problem. In this work we compare the ability to reproduce various condensed phase properties by six distinct sets of force field parameters which can be assigned to phospholipid hydrocarbon chains. In this comparison, we include three alternative sets of the OPLS-AA force field, as well as the commonly used CHARMM C36, Slipids, and Berger lipids’ parameters.

GAGs-Potentiated Inhibition of Thrombin, Factor Xa and Plasmin in Plasma and in a Purified System Containing Antithrombin III – Correlation with Total Charge Density

1981 ◽  
Vol 46 (04) ◽  
pp. 749-751 ◽  
Author(s):  
E Cofrancesco ◽  
A Vigo ◽  
E M Pogliani
Keyword(s):  
Charge Density ◽  
Chemical Structure ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Total Charge ◽  
Pure System ◽  
At Iii ◽  
Total Charge Density ◽  
The Difference ◽  
Inhibition Of Thrombin

SummaryThe ability of heparin and related glycosaminoglycans (GAGs) to accelerate the inhibition of thrombin, factor Xa and plasmin in plasma and in a purified system containing antithrombin III (At III) was studied using chromogenic peptide substrate assaysThere was a good correlation between the charge density of the mucopolysaccharides and the activities investigated. While the difference between potentiation of the antithrombin activity by GAGs in plasma and in the purified system was slight, the inhibition of factor Xa in plasma was more pronounced than in the presence of purified At III, indicating the mechanisms for GAGs-potentiated inhibition of thrombin and factor Xa are not identical.For the antiplasmin activity, there was a good correlation between the chemical structure and biological activity only in the pure system, confirming that the antithrombin-GAG complex plays a very limited role in the inactivation of plasmin in plasma.

Evaluation of Salivary Antioxidants and Oxidative Stress Markers in Type 2 Diabetes Mellitus: A Retrospective Cohort Study

2020 ◽  
Vol 20 (4) ◽  
pp. 584-590 ◽  
Author(s):  
Shima Fathi ◽  
Shiva Borzouei ◽  
Mohammad Taghi Goodarzi ◽  
Jalal Poorolajal ◽  
Fatemeh Ahmadi-Motamayel
Keyword(s):  
Oxidative Stress ◽  
Diabetes Mellitus ◽  
Control Group ◽  
Oxidative Stress Markers ◽  
Stress Markers ◽  
Type 2 Dm ◽  
Patients With Diabetes ◽  
The Difference ◽  
And Oxidative Stress

Background: Diabetes Mellitus (DM) is a progressive metabolic disorder. Objective: The aim of this study was to investigate the relationship between antioxidant and oxidative stress markers in the saliva of patients with type 2 DM and a healthy control group. Methods: In this study, 20 patients with diabetes and 20 healthy individuals were evaluated. Salivary antioxidants markers consisted of total antioxidant capacity (TAC), uric acid (UA), peroxidase and catalase. Oxidative stress markers included total oxidant status (TOS), malondealdehyde (MDA) and total thiol (SH). Sialochemical analysis was performed with spectrophotometric assay. All the statistical analyses were conducted using STATA software. Results: TAC decreased significantly in patients with diabetes. Although salivary UA and peroxidase were lower in patients with diabetes compared to the control group, the difference was not significant. Salivary catalase in patients with diabetes was significantly lower than that in the control group. MDA and TOS exhibited significantly higher levels in type 2 DM. SH levels were slightly higher in DM. Conclusions: According to the results of the present study, there were some changes in the salivary levels of some antioxidants and oxidative stress markers in patients with type 2 DM and could be measured as an indicator of serum changes..

Management of Vatarakta w.s.r. to Gout through Panchakarma

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Dr. Chandramohan Arya ◽  
Dr.Sanjay Gupta
Keyword(s):  
Metabolic Disorders ◽  
Molecular Level ◽  
Modern Science ◽  
Monosodium Urate ◽  
Monosodium Urate Crystals ◽  
Predominant Symptom ◽  
Essential Components ◽  
Unique Approach ◽  
Ayurvedic Treatment ◽  
Urate Crystals

Vatarakta is more distressing and common metabolic disorder prevalent in present era. It is Vatapradhana Tridoshaja Vatavyadhi where Rakta is main Dushya. Vata is a predominant Dosha in Vatarakta, when it is excessively aggravated with vitiated Rakta is called Vatarakta. Vatarakta is correlated with gout in modern science. Gout is an abnormality of purine metabolism causes hyperuricemia and deposition of monosodium urate crystals in joints. Pain is predominant symptom of gout, which disturbs day-today life of the patients. The Panchakarma is not only a important component of Ayurvedic treatment but it is also forms the fundamental basis of Ayurveda therapy. The different procedures like Swedana, Vamana, Virechana, Basti, Sirovirechana, Raktamokshana focus on the purification which detoxifies the human body, i.e. the correction of the metabolism at molecular level. These detoxification procedures are essential components of the management in various metabolic disorders. So Panchakarma is an unique approach in the management of Vatarakta.

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

scholarly journals Separation and not residency permit restores function in resignation syndrome: a retrospective cohort study

2021 ◽  
Author(s):  
Karl Sallin ◽  
Kathinka Evers ◽  
Håkan Jarbin ◽  
Lars Joelsson ◽  
Predrag Petrovic
Keyword(s):  
Cohort Study ◽  
Social Services ◽  
Residential Care ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Care Home ◽  
Essential Components ◽  
Residential Care Home ◽  
The Difference ◽  
Oriented Approach

AbstractDespite poor treatment results, a family-oriented approach and the securing of residency have been deemed essential to recovery from resignation syndrome (RS). In a retrospective cohort study, we evaluated an alternative method involving environmental therapy, with patients separated from their parents, while actively abstaining from involving the asylum process in treatment. We examined medical records, social services acts, and residential care home acts from 13 individuals treated at Solsidan residential care home between 2005 and 2020. Severity and outcome were assessed with Clinical Global Impression, Severity and Improvement subscales. Thirteen participants were included and out of these nine (69%) recovered, i.e. they very much or much improved. Out of the eight that were separated, all recovered, also, one non-separated recovered. The difference in outcome between subjects separated and not was significant (p = 0.007). Moreover, out of the five which received a residency permit during treatment, one recovered whereas four did not. The difference in outcome between subjects granted residency and not was significant (p = 0.007). The data revealed three (23%) cases of simulation where parents were suspected to have instigated symptoms. Our evaluation suggests that separation from parents and abstaining from invoking residency permit could be essential components when treating RS. Relying on a family-oriented approach, and residency could even be detrimental to recovery. The examined intervention was successful also in cases of probable malingering by proxy.

scholarly journals Influence of Dimethacrylate Monomer on the Polymerization Efficacy of Resin-Based Dental Cements—FTIR Analysis

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 247
Author(s):  
Aleksandra Maletin ◽  
Ivan Ristic ◽  
Tanja Veljovic ◽  
Bojana Ramic ◽  
Tatjana Puskar ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Clinical Practice ◽  
Chemical Structure ◽  
Cementitious Materials ◽  
Degree Of Polymerization ◽  
Cementitious Material ◽  
Ftir Analysis ◽  
Dental Cement ◽  
Polymerization Mechanism ◽  
The Difference

The degree of polymerization for dimethacrylate resin-based materials (BisGMA, TEGDMA, UDMA, HEMA) ranges from 55 to 75%. Literature data indicate that polymerization efficacy depends, among other factors, on the type of methacrylate resin comprising the material. The aim of this study was to evaluate the polymerization efficacy of four dental cement materials characterized by different polymerization mechanisms using FTIR analysis. In the present study, the FTIR method was adopted to analyze the degree of polymerization efficacy of four resin-based dental cement materials, two of which were self-cured and two were dual-cured cements. The IR spectral analysis was performed 24 h after the polymerization of the cementitious material. RelyX ARC cement exhibits the lowest polymerization efficacy (61.3%), while that of Variolink II (85.8%) and Maxcem Elite is the highest (90.1%). Although the efficacy of self-cured cements appears to be superior, the difference is not statistically significant (p = 0.280). Polymerization efficacy largely depends on the chemical structure of the material in terms of the presence of a particular methacrylate resin and less on the polymerization mechanism itself, i.e., whether it is a self-cured or dually cured dental cement. Thus, in clinical practice, cementitious materials with a higher proportion of TEGDMA compared with BisGMA are recommended.

scholarly journals The system of the quality control and the safety of baby food, the prospects of its development

2019 ◽  
Vol 95 (11) ◽  
pp. 1091-1095
Author(s):  
Olga V. Georgieva ◽  
L. S. Konovalova ◽  
I. Ya. Kon'
Keyword(s):  
Human Milk ◽  
Infant Nutrition ◽  
Baby Food ◽  
Customs Union ◽  
Quality And Safety ◽  
Food Ration ◽  
Essential Components ◽  
Legislative Framework ◽  
The Difference ◽  
European Standards

In the article there is considered the substantiation of raise demands to the chemical composition of children’s food and indices of their safety, with taking into account the immaturity of metabolic and physiological processes and limitations of “depot” of nutrients in babies. Based on research results of leading experts in the field of children’s nutritiology and according to the recommendations of the Codex Alimentarius of the Commission of FAO/WHO, ESPGHAN Committee on Nutrition, the EFSA recommendations and EUDirectives there were specified requirements for the ingredient composition, content of essential components and indices of the nutritional value of substitutes for human milk and functional products for the nutrition of infants of the first year of life. There are shown stages of the development of the Russian system of hygienic requirements for baby food, and the direction of its harmonization with international and European standards, particularly for substitutes for human milk and products of dietary therapeutic and dietary preventive nutrition for babies. There are considered aspects of the introduction ofproducts and weaning food dishes into the food ration of infants. There is presented the classification ofproducts of children’s food and the assortment of each group of weaning foods. There is provided the modern legislative framework in the field of the quality and safety for infant nutrition. There was shown the difference between domestic legislation and regulatory framework of the EurAsEC Customs Union of the European countries in the field offood products safety for children older three years. There are presented proposals on the creation of the single regulatory base within the framework of the EurAsEC Customs Union for control the quality and safety of all the baby foods

Selective arrangement of vesicles on artificial lipid membrane by biotin-avidin interaction

2021 ◽  
Author(s):  
Kai Hashino ◽  
Daiya Mombayashi ◽  
Yuto Nakatani ◽  
Azusa Oshima ◽  
Masumi Yamaguchi ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Liquid Crystalline ◽  
Lipid Membrane ◽  
Unsaturated Lipid ◽  
Si Substrates ◽  
Phase Domain ◽  
Unsaturated Lipids ◽  
Lipid Mixtures ◽  
The Difference

Abstract Lipid bilayers suspended over microwells on Si substrates are promising platforms for nanobiodevices that mimic cell membranes. Using the biotin-avidin interaction, we have succeeded in selectively arranging vesicles on the freestanding region of a lipid bilayer. When ternary lipid mixtures of saturated lipid, unsaturated lipid, and cholesterol are used, they separate into liquid-order (Lo) and liquid-crystalline (Lα) domains. A freestanding lipid bilayer prefers the Lα-phase over the Lo-phase because of the difference in their flexibility. In addition, the type of biotinylated lipid determines whether it is localized in the Lα-phase domain or the Lo-phase domain. As a result, the biotinylated unsaturated lipids localized in the Lα-phase domain aggregate in the freestanding lipid bilayer, and vesicles labeled with biotin selectively bind to the freestanding lipid bilayer by the biotin-avidin interaction. This technique helps to introduce biomolecules into the freestanding lipid bilayer of nanobiodevices via vesicles.

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