We measured diurnal variations in oxidative stress conditions of cyanobacteria utilizing field observations and laboratory experiments in order to evaluate photoinhibition effects. On clear summer days, transparent bottles filled with surface water were set up at several depths and were collected every three hours together with the measurement of the photosynthetically active radiation (PAR). In the laboratory experiment, two cyanobacterial species were exposed to gradually increasing and then decreasing light intensities. The samples were analyzed with the PAR-induced (HO), along with the total hydrogen peroxide concentrations (total HO), the catalase activities (CAT), OD, protein (Protein), and chlorophyll a (Chl a) contents, and so on. Protein was significantly proportionate with OD and Chl a, and was used as an indicator of cell biomass. Increasing PAR, HO concentration increased proportionately with the PAR intensity. Then, an oxidative stress indicator in a cell, HO/Protein is given by the PAR divided by cell volume, evaluated by Protein. CAT activity in a cell, far largest among antioxidant activities, solely followed total HO/Protein. The prediction model for HO/Protein was developed with the sufficient agreement with the experimental and field observation results. The model elucidated that the maximum HO/Protein in a day was larger with lower cell density even at the water surface, indicating that the higher photoinhibition was imposed at low density, in addition to the lower attenuation of PAR. These results indicate that HO/Protein is an effective biomarker to indicate the stress level of cyanobacteria; the observed levels of HO to freshwater may prove useful in designing the criteria for cyanobacteria management.
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http://dx.doi.org/10.1038/s41598-024-80269-6 | DOI Listing |
Mol Cell Biochem
December 2024
Department XIII Infectious Diseases-Parasitology, "Victor Babeș" University of Medicine and Pharmacy of Timișoara, Timișoara, Romania.
The global burden of cancer as a major cause of death and invalidity has been constantly increasing in the past decades. Monoamine oxidases (MAO) with two isoforms, MAO-A and MAO-B, are mammalian mitochondrial enzymes responsible for the oxidative deamination of neurotransmitters and amines in the central nervous system and peripheral tissues with the constant generation of hydrogen peroxide as the main deleterious ancillary product. However, given the complexity of cancer biology, MAO involvement in tumorigenesis is multifaceted with different tumors displaying either an increased or decreased MAO profile.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Department of Experimental Medicine, Biotechnology, and Molecular Biology Section, Luigi Vanvitelli Campania University, Naples, Italy.
Mesenchymal stromal cells (MSCs) are a heterogeneous population of non-hematopoietic adult stem cells derived from the embryonic mesoderm. They possess self-renewal and multipotent differentiation capabilities, allowing them to give rise to mesodermal cell types, such as osteoblasts, chondroblasts, and adipocytes, as well as non-mesodermal cells, including neuron-like cells and endothelial cells. MSCs play a vital role in maintaining homeostasis across various tissues by facilitating tissue repair, immune regulation, and inflammatory response balance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Dalian Institute of Chemical Physics, Dalian National Laboratory for Clean Energy, State Key Laboratory of Catalysis, Zhongshan Road 457., 116023, Dalian, CHINA.
The photocatalytic oxidation of water with gaseous oxygen is environmentally benign for the synthesis of hydrogen peroxide (H2O2), but it is currently constrained by the inadequate supply of gaseous oxygen at the catalyst surface in a solid-liquid-gas triple-phase reaction system. Herein, we address this challenge by employing the zeolite encapsulated catalysts that efficiently enrich gaseous oxygen and accelerate the H2O2 synthesis in in aqueous conditions. We focus on the classical titania photocatalyst, encapsulating it within siliceous MFI zeolite crystals.
View Article and Find Full Text PDFChembiochem
December 2024
The University of Adelaide, Department of Chemistry, North Terrace, 5005, Adelaide, AUSTRALIA.
The heme enzymes of the cytochrome P450 superfamily (CYPs) catalyse the selective hydroxylation of unactivated C-H bonds in organic molecules. There is great interest in applying these enzymes as biocatalysts with a focus on self-sufficient CYP 'fusion' enzymes, comprising a single polypeptide chain with the electron transfer components joined to the heme domain. Here we elucidate the function of the self-sufficient CYP116B46 fusion enzyme, from the thermophilic bacterium Tepidiphilus thermophilus.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Hunan University, College of Chemistry and Chemical Engineering, No.2 Lushan Southroad, 410000, Changsha, CHINA.
Mimicking natural enzymes through artificial enzyme engineering represents a powerful strategy to fine-tune the performance of photocatalysts, while the manipulation of electron transfer systems through atomic precision control is challenging. Herein, we reported a series of covalent organic frameworks (COFs) based on progressively oxidized phenothiazine (PTH) core as the platform for emulating Coenzyme Q, achieved through meticulous stepwise adjustments of their redox states. Compared to the original PTH-S-COF, the COFs with incrementally oxidized sulfur sites exhibited enhanced charge transfer efficiencies, facilitating efficient electron donation to O2 and thereby providing a favorable pathway for H2O2 synthesis.
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