scholarly journals Influence of Amino Acids on the Mobility of Iodide in Hydrocalumite

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 836
Author(s):  
Mengmeng Wang ◽  
Hirofumi Akamatsu ◽  
Keiko Sasaki
Keyword(s):  
Amino Acids ◽  
Ion Exchange ◽  
Interlayer Spacing ◽  
Organic Substances ◽  
Cement System ◽  
Anionic Species ◽  
Alkaline Conditions ◽  
Living Organisms ◽  
The Stability ◽  
Formation Energies

In the cement system, hydrocalumite is a candidate adsorbent for low-level 129I anionic species. However, the stability of hydrocalumite after immobilizing I− is unclear when they are exposed to pedosphere characterized by organic substances derived from living organisms. In the present work, five amino acids were selected as simplified models of natural organic substances under alkaline conditions. L-cysteine (H2Cys) and L-aspartic acid (H2Asp) accelerated the release of I− from I-hydrocalumite through ion-exchange. Ion-exchange of Cys2− with I− in I-hydrocalumite was faster than Asp2−, and the interlayer spacing (d003) of Cys-hydrocalumite was smaller than that of Asp-hydrocalumite. DFT simulations not only supported the above results but also predicted that there was a positive correlation between the formation energies and interlayer spacings of amino acids intercalated hydrocalumite, depending on the configurations. Moreover, in the DFT predictions, the interaction between amino acids and metallic hydroxide layers was responsible for the formation of hydrogen bonds and Ca-O chemical bonds between the -COO− groups and [Ca2Al(OH)6]+. The other three amino acids did not show intercalation through ion-exchange. The stability of I-hydrocalumite is influenced differently by coexisting amino acids, depending on the ionic sizes, charge numbers, and hydrophilicity, which cause the second contamination.

scholarly journals UVA and UVB Photoprotective Capabilities of Topical Formulations Containing Mycosporine-like Amino Acids (MAAs) through Different Biological Effective Protection Factors (BEPFs)

Marine Drugs ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 55 ◽  
Author(s):  
Francisca de la Coba ◽  
José Aguilera ◽  
Nathalie Korbee ◽  
María de Gálvez ◽  
Enrique Herrera-Ceballos ◽  
...  
Keyword(s):  
Amino Acids ◽  
In Vitro Tests ◽  
Antioxidant Compounds ◽  
Protection Factor ◽  
Effective Protection ◽  
Alkaline Conditions ◽  
Solar Uv ◽  
The Stability ◽  
Ph Range

The safety and stability of synthetic UV-filters and the procedures for evaluating the photoprotective capability of commercial sunscreens are under continuous review. The influence of pH and temperature stressors on the stability of certain Mycosporine-like amino acids (MAAs) isolated at high purity levels was examined. MAAs were highly stable at room temperature during 24 h at pH 4.5–8.5. At 50 °C, MAAs showed instability at pH 10.5 while at 85 °C, progressive disappearances were observed for MAAs through the studied pH range. In alkaline conditions, their degradation was much faster. Mycosporine-serinol and porphyra-334 (+shinorine) were the most stable MAAs under the conditions tested. They were included in four cosmetically stable topical sunscreens, of which the Sun Protection Factor (SPF) and other Biological Effective Protection Factors (BEPFs) were calculated. The formulation containing these MAAs showed similar SPF and UVB-BEPFs values as those of the reference sunscreen, composed of synthetic UV absorbing filters in similar percentages, while UVA-BEPFs values were slightly lower. Current in vitro data strongly suggest that MAAs, as natural and safe UV-absorbing and antioxidant compounds, have high potential for protection against the diverse harmful effects of solar UV radiation. In addition, novel complementary in vitro tests for evaluation of commercial sunscreens efficacy are proposed.

Stability of non-proteinogenic amino acids to UV and gamma irradiation

2018 ◽  
Vol 18 (05) ◽  
pp. 426-435 ◽  
Author(s):  
Laura Rowe ◽  
Julie Peller ◽  
Claire Mammoser ◽  
Kelly Davidson ◽  
Amy Gunter ◽  
...  
Keyword(s):  
Amino Acids ◽  
High Performance ◽  
Gamma Ray ◽  
Uv Light ◽  
Fundamental Property ◽  
Environmental Pressures ◽  
Gamma Ray Irradiation ◽  
Living Organisms ◽  
The Stability ◽  
Almost All

AbstractAlmost all living organisms on Earth utilize the same 20 amino acids to build their millions of different proteins, even though there are hundreds of amino acids naturally occurring on Earth. Although it is likely that both the prebiotic and the current environment of Earth shaped the selection of these 20 proteinogenic amino acids, environmental conditions on extraterrestrial planets and moons are known to be quite different than those on Earth. In particular, the surfaces of planets and moons such as Mars, Europa and Enceladus have a much greater flux of UV and gamma radiation impacting their surface than that of Earth. Thus, if life were to have evolved extraterrestrially, a different lexicon of amino acids may have been selected due to different environmental pressures, such as higher radiation exposure. One fundamental property an amino acid must have in order to be of use to the evolution of life is relative stability. Therefore, we studied the stability of three different proteinogenic amino acids (tyrosine, phenylalanine and tryptophan) as compared with 20 non-proteinogenic amino acids that were structurally similar to the aromatic proteinogenic amino acids, following ultraviolet (UV) light (254, 302, or 365 nm) and gamma-ray irradiation. The degree of degradation of the amino acids was quantified using an ultra-high performance liquid chromatography-mass spectrometer (UPLC-MS). The result showed that many non-proteinogenic amino acids had either equal or increased stability to certain radiation wavelengths as compared with their proteinogenic counterparts, with fluorinated phenylalanine and tryptophan derivatives, in particular, exhibiting enhanced stability as compared with proteinogenic phenylalanine and tryptophan amino acids following gamma and select UV irradiation.

Epigenetic Mechanisms of Maternal Dietary Protein and Amino Acids Affecting Growth and Development of Offspring

2019 ◽  
Vol 20 (7) ◽  
pp. 727-735 ◽  
Author(s):  
Yi Wu ◽  
Zhibin Cheng ◽  
Yueyu Bai ◽  
Xi Ma
Keyword(s):  
Amino Acids ◽  
Dna Methylation ◽  
Dietary Protein ◽  
Growth And Development ◽  
Later Life ◽  
Biological Macromolecules ◽  
Epigenetic Mechanisms ◽  
Maternal Circulation ◽  
Energy Processing ◽  
Living Organisms

Nutrients can regulate metabolic activities of living organisms through epigenetic mechanisms, including DNA methylation, histone modification, and RNA regulation. Since the nutrients required for early embryos and postpartum lactation are derived in whole or in part from maternal and lactating nutrition, the maternal nutritional level affects the growth and development of fetus and creates a profound relationship between disease development and early environmental exposure in the offspring’s later life. Protein is one of the most important biological macromolecules, involved in almost every process of life, such as information transmission, energy processing and material metabolism. Maternal protein intake levels may affect the integrity of the fetal genome and alter DNA methylation and gene expression. Most amino acids are supplied to the fetus from the maternal circulation through active transport of placenta. Some amino acids, such as methionine, as dietary methyl donor, play an important role in DNA methylation and body’s one-carbon metabolism. The purpose of this review is to describe effects of maternal dietary protein and amino acid intake on fetal and neonatal growth and development through epigenetic mechanisms, with examples in humans and animals.

A review of lignin hydrogen peroxide oxidation chemistry with emphasis on aromatic aldehydes and acids

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajinkya More ◽  
Thomas Elder ◽  
Zhihua Jiang
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Degradation ◽  
Reaction Medium ◽  
Dicarboxylic Acids ◽  
Aromatic Aldehydes ◽  
Product Distribution ◽  
Reaction Conditions ◽  
Alkaline Conditions ◽  
The Stability ◽  
Oxidation Chemistry

Abstract This review discusses the main factors that govern the oxidation processes of lignins into aromatic aldehydes and acids using hydrogen peroxide. Aromatic aldehydes and acids are produced in the oxidative degradation of lignin whereas mono and dicarboxylic acids are the main products. The stability of hydrogen peroxide under the reaction conditions is an important factor that needs to be addressed for selectively improving the yield of aromatic aldehydes. Hydrogen peroxide in the presence of heavy metal ions readily decomposes, leading to minor degradation of lignin. This degradation results in quinones which are highly reactive towards peroxide. Under these reaction conditions, the pH of the reaction medium defines the reaction mechanism and the product distribution. Under acidic conditions, hydrogen peroxide reacts electrophilically with electron rich aromatic and olefinic structures at comparatively higher temperatures. In contrast, under alkaline conditions it reacts nucleophilically with electron deficient carbonyl and conjugated carbonyl structures in lignin. The reaction pattern in the oxidation of lignin usually involves cleavage of the aromatic ring, the aliphatic side chain or other linkages which will be discussed in this review.

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