UV-B illumination facilitates aggregation of alpha-lactalbumin (α-LA) by intramolecular disulfide bond cleavage followed by intermolecular thiol-disulfide exchange reactions. However, long term exposure to UV-B illumination may induce undesired oxidative modifications of amino acid residues in the protein. The purpose of this study was to examine the effect of UV-induced aggregation of apo-α-LA (a calcium-depleted form of α-LA) under aerobic and anaerobic conditions and by addition of tryptophan (Trp) as a photosensitizer. The addition of Trp to apo-α-LA illuminated under anaerobic conditions facilitated the highest level of free thiol release and disulfide-mediated aggregation as compared to without addition of Trp under both anaerobic and aerobic conditions. Addition of Trp under aerobic condition resulted in the lowest level of free thiols and disulfide-mediated aggregation and the aerobic conditions caused oxidation of the free Trp with formation of kynurenine and 5-hydroxy-Trp. Minor levels of the Trp oxidation product, 3-hydroxy-kynurenine (2% converted from Trp), was formed in apo-α-LA with added Trp under both aerobic and anaerobic conditions after UV-B treatment.
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http://dx.doi.org/10.3390/foods10071577 | DOI Listing |
Microorganisms
December 2024
Laboratory for Skin Research, Institute for Medical Research, Galilee Medical Center, Nahariya 2210001, Israel.
Facultatively anaerobic spp. and anaerobic spp. are among the most prominent bacteria on human skin.
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December 2024
Nanchang Key Laboratory of Microbial Resources Exploitation & Utilization from Poyang Lake Wetland, College of Life Sciences, Jiangxi Normal University, Nanchang 330022, China.
Poyang Lake is the largest freshwater lake in China, which boasts unique hydrological conditions and rich biodiversity. In this study, metagenomics technology was used to sequence the microbial genome of soil samples S1 (sedimentary), S2 (semi-submerged), and S3 (arid) with different water content from the Poyang Lake wetland; the results indicate that the three samples have different physicochemical characteristics and their microbial community structure and functional gene distribution are also different, resulting in separate ecological functions. The abundance of typical ANME archaea and the high abundance of in S1 mutually demonstrate prominent roles in the methane anaerobic oxidation pathway during the methane cycle.
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November 2024
NP3, Nutrition, PathoPhysiology and Pharmacology Unit, Oniris VetAgro Bio, Nantes-Atlantic College of Veterinary Medicine, Food Science and Engineering, La Chantrerie, CEDEX 03, 44307 Nantes, France.
To investigate the role of the intestinal bacterial microbiota in the pathogenesis of calcium oxalate nephrolithiasis in cats, a condition characterized by the formation of kidney stones, it is desirable to identify a sample collection method that accurately reflects the microbiota's composition. The objective of this study was to evaluate the impact of fecal sample collection methods on the intestinal microbiota composition in two cat populations: healthy cats and kidney stone-diseased cats. The study included eighteen cats from the same colony, comprising nine healthy cats and nine cats with spontaneously occurring presumed calcium oxalate kidney stones.
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December 2024
Faculty of Energy and Fuels, AGH University, al. Mickiewicza 30, 30 059 Kraków, Poland.
A multipronged approach to the refined mechanochemical synthesis of the semiconductor kesterite CuZnSnS with minimal quantities of adventitious oxygen as well as to optimizing handling procedures from that angle is described. Three precursor systems are used to provide a pool of freshly made cubic prekesterite nanopowders with no semiconductor properties and the thermally annealed at 500 °C tetragonal kesterite nanopowders of the semiconductor. Based on the previously reported high propensity of such nanopowders to long-term deteriorating oxidation in ambient air, suitable modifications of all crucial synthesis steps are implemented, which are directed toward excluding or limiting the materials' exposure to air.
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December 2024
Xi'an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, No. 17 Cuihua South Road, Xi'an 710061, China.
is a traditional Chinese medicinal plant of considerable application value and commercial potential, primarily due to its production of various bioactive compounds, particularly dammarane-type triterpenoid saponins that are structurally analogous to ginsenosides. Oxidosqualene cyclase (OSC), a pivotal enzyme in the biosynthesis of triterpenoid metabolites in plants, catalyzes the conversion of oxidosqualene into triterpenoid precursors, which are essential components of the secondary metabolites found in . To elucidate the role of gene family members in the synthesis of gypenosides within , this study undertook a comprehensive genome-wide identification and characterization of genes within and compared their expression levels across populations distributed over different geographical regions by both transcriptome sequencing and qRT-PCR experimental validation.
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