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1.
Ultrason Sonochem ; 107: 106945, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38857567

RESUMEN

In this study, large yellow croaker (Larimichthys crocea) was frozen using multi-frequency ultrasound-assisted freezing (MUIF) with different powers (160 W, 175 W, and 190 W, respectively) and stored at -18 °C for ten months. The effect of different ultrasound powers on the myofibrillar protein (MP) structures and lipid oxidation of large yellow croaker was investigated. The results showed that MUIF significantly slowed down the oxidation of MP by inhibiting carbonyl formation and maintaining high sulfhydryl contents. These treatments also held a high activity of Ca2+-ATPase in the MP. MUIF maintained a higher ratio of α-helix to ß-sheet during frozen storage, thereby protecting the secondary structure of the tissue and stabilizing the tertiary structure. In addition, MUIF inhibited the production of thiobarbituric acid reactive substances value and the loss of unsaturated fatty acid content, indicating that MUIF could better inhibit lipid oxidation of large yellow croaker during long-time frozen storage.


Asunto(s)
Congelación , Oxidación-Reducción , Perciformes , Animales , Factores de Tiempo , Almacenamiento de Alimentos , Proteínas Musculares/química , Proteínas Musculares/metabolismo , Ondas Ultrasónicas , ATPasas Transportadoras de Calcio/metabolismo
2.
J Fungi (Basel) ; 10(1)2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38276033

RESUMEN

Lipid droplets (LDs) are intracellular organelles that play important roles in cellular lipid metabolism; they change their sizes and numbers in response to both intracellular and extracellular signals. Changes in LD size reflect lipid synthesis and degradation and affect many cellular activities, including energy supply and membrane synthesis. Here, we focused on the function of the endoplasmic reticulum-plasma membrane tethering protein Ice2 in LD dynamics in the fungal pathogen Candida albicans (C. albicans). Nile red staining and size quantification showed that the LD size increased in the ice2Δ/Δ mutant, indicating the critical role of Ice2 in the regulation of LD dynamics. A lipid content analysis further demonstrated that the mutant had lower phosphatidylcholine levels. As revealed with GFP labeling and fluorescence microscopy, the methyltransferase Cho2, which is involved in phosphatidylcholine synthesis, had poorer localization in the plasma membrane in the mutant than in the wild-type strain. Interestingly, the addition of the phosphatidylcholine precursor choline led to the recovery of normal-sized LDs in the mutant. These results indicated that Ice2 regulates LD size by controlling intracellular phosphatidylcholine levels and that endoplasmic reticulum-plasma membrane tethering proteins play a role in lipid metabolism regulation in C. albicans. This study provides significant findings for further investigation of the lipid metabolism in fungi.

3.
Microbiol Res ; 279: 127552, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38000336

RESUMEN

Histone proteins are important components of nucleosomes, which play an important role in regulating the accessibility of DNA and the function of genomes. However, the effect of histone proteins dosages on physiological processes is not clear in the human fungal pathogen Candida albicans. In this study, we found that the deletion of the histone protein H3 coding gene HHT21 and the histone protein H4 coding gene HHF1 resulted in a significant decrease in the expression dosage of the histone proteins H3 and H4, which had a significant impact on the localization of the histone protein H2A and plasmid maintenance. Stress sensitivity experiments showed that the mutants hht21Δ/Δ, hhf1Δ/Δ and hht21Δ/Δhhf1Δ/Δ were more sensitive to cell wall stress induced by Calcofluor White (CFW) than the wild-type strain. Further studies showed that the decrease in the dosage of the histone proteins H3 and H4 led to the change of cell wall components, increased chitin contents, and down-regulated expression of the SAP9, KAR2, and CRH11 genes involved in the cell wall integrity (CWI) pathway. Overexpression of SAP9 could rescue the sensitivity of the mutants to CFW. Moreover, the decrease in the histone protein s dosages affected the FAD-catalyzed oxidation of Ero1 protein, resulting in the obstruction of protein folding in the ER, and thus reduced resistance to CFW. It was also found that CFW induced a large amount of ROS accumulation in the mutants, and the addition of ROS scavengers could restore the growth of the mutants under CFW treatment. In addition, the reduction of the histone proteins dosages greatly weakened systemic infection and kidney fungal burden in mice, and hyphal development was significantly impaired in the mutants under macrophage treatment, indicating that the histone proteins dosages is very important for the virulence of C. albicans. This study revealed that histone proteins dosages play a key role in the cell wall stress response and pathogenicity in C. albicans.


Asunto(s)
Candida albicans , Proteínas Fúngicas , Humanos , Animales , Ratones , Proteínas Fúngicas/metabolismo , Virulencia , Histonas/genética , Histonas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Pared Celular/metabolismo
4.
iScience ; 26(12): 108434, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38125022

RESUMEN

The efficient conversion of CO2 is considered to be an important step toward carbon emissions peak and carbon neutrality. Presently, great efforts have been devoted to the study of efficient nanocatalysts, electrolytic cell, and electrolytes to achieve high reactivity and selectivity in the electrochemical reduction of CO2 to mono- and multi-carbon (C2+) compounds. However, there are very few reviews focusing on highly reactive and selective ethylene production and application in the field of electrochemical carbon dioxide reduction reaction (CO2RR). Ethylene is a class of multi-carbon compounds that are widely applied in industrial, ecological, and agricultural fields. This review focuses especially on the convertibility of CO2 reduction to generate ethylene technology in practical applications and provides a detailed summary of the latest technologies for the efficient production of ethylene by CO2RR and suggests the potential application of CO2RR systems in food science to further expand the application market of CO2RR for ethylene production.

5.
J Fungi (Basel) ; 9(12)2023 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-38132782

RESUMEN

DNA damage activates the DNA damage response and autophagy in C. albicans; however, the relationship between the DNA damage response and DNA damage-induced autophagy in C. albicans remains unclear. Mec1-Rad53 signaling is a critical pathway in the DNA damage response, but its role in DNA damage-induced autophagy and pathogenicity in C. albicans remains to be further explored. In this study, we compared the function of autophagy-related (Atg) proteins in DNA damage-induced autophagy and traditional macroautophagy and explored the role of Mec1-Rad53 signaling in regulating DNA damage-induced autophagy and pathogenicity. We found that core Atg proteins are required for these two types of autophagy, while the function of Atg17 is slightly different. Our results showed that Mec1-Rad53 signaling specifically regulates DNA damage-induced autophagy but has no effect on macroautophagy. The recruitment of Atg1 and Atg13 to phagophore assembly sites (PAS) was significantly inhibited in the mec1Δ/Δ and rad53Δ/Δ strains. The formation of autophagic bodies was obviously affected in the mec1Δ/Δ and rad53Δ/Δ strains. We found that DNA damage does not induce mitophagy and ER autophagy. We also identified two regulators of DNA damage-induced autophagy, Psp2 and Dcp2, which regulate DNA damage-induced autophagy by affecting the protein levels of Atg1, Atg13, Mec1, and Rad53. The deletion of Mec1 or Rad53 significantly reduces the ability of C. albicans to systematically infect mice and colonize the kidneys, and it makes C. albicans more susceptible to being killed by macrophages.

6.
Proc Natl Acad Sci U S A ; 120(40): e2305961120, 2023 10 03.
Artículo en Inglés | MEDLINE | ID: mdl-37751556

RESUMEN

α-lipoic acid (LA) is an essential cofactor for mitochondrial dehydrogenases and is required for cell growth, metabolic fuel production, and antioxidant defense. In vitro, LA binds copper (Cu) with high affinity and as an endogenous membrane permeable metabolite could be advantageous in mitigating the consequences of Cu overload in human diseases. We tested this hypothesis in 3T3-L1 preadipocytes with inactivated Cu transporter Atp7a; these cells accumulate Cu and show morphologic changes and mitochondria impairment. Treatment with LA corrected the morphology of Atp7a-/- cells similar to the Cu chelator bathocuproinedisulfonate (BCS) and improved mitochondria function; however, the mechanisms of LA and BCS action were different. Unlike BCS, LA did not decrease intracellular Cu but instead increased selenium levels that were low in Atp7a-/- cells. Proteome analysis confirmed distinct cell responses to these compounds and identified upregulation of selenoproteins as the major effect of LA on preadipocytes. Upregulation of selenoproteins was associated with an improved GSH:GSSG ratio in cellular compartments, which was lowered by elevated Cu, and reversal of protein oxidation. Thus, LA diminishes toxic effects of elevated Cu by improving cellular redox environment. We also show that selenium levels are decreased in tissues of a Wilson disease animal model, especially in the liver, making LA an attractive candidate for supplemental treatment of this disease.


Asunto(s)
Selenio , Ácido Tióctico , Animales , Humanos , Ácido Tióctico/farmacología , Cobre , Selenio/farmacología , Oxidación-Reducción , Selenoproteínas/genética
7.
J Sci Food Agric ; 103(15): 7747-7756, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37439124

RESUMEN

BACKGROUND: Improper stunning methods before slaughter could cause fish to deteriorate more quickly during cold storage. However, it is unclear how stunning methods affect the mitochondrial structure and the role of mitochondria in oxidation in muscle-based food. RESULTS: This study explored the potential mechanism of oxidation induced by different stunning methods (hit on the head, T1 ; gill cut, T2 ; immersion in ice/water slurry, T3 ; CO2 asphyxiated, T4 ; 40% CO2 + 30% N2 + 30% O2 , T5 ) in large yellow croaker during cold storage. The results showed that T4 samples had the minimum stress response and the mitochondrial membrane potential and permeability were less damaged. Besides, the mitochondrial functional structure and peroxisome of T4 samples were less damaged compared with other samples, which was reflected in higher total superoxide dismutase, catalase and glutathione peroxidase activities. In terms of oxidation indices, the T4 samples showed higher pH values and iron myoglobin contents and lower total volatile basic nitrogen and thiobarbituric acid reactive substances after 168 h cold storage, indicating that the T4 samples significantly maintained oxidative stability of large yellow croaker. CONCLUSION: The CO2 asphyxiation had the least oxidative damage to large yellow croaker during cold storage, possibly because it had the least effect on mitochondrial structure, reactive oxygen species and antioxidant enzyme activity. © 2023 Society of Chemical Industry.


Asunto(s)
Dióxido de Carbono , Perciformes , Animales , Oxidación-Reducción , Antioxidantes/metabolismo , Mitocondrias/metabolismo
8.
Chem Commun (Camb) ; 59(64): 9675-9686, 2023 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-37455615

RESUMEN

An organoid is a 3-dimensional (3D) cell culture system that mimics the structural and functional characteristics of organs, and it has promising applications in regenerative medicine, precision drug screening and personalised therapy. However, current culture techniques of organoids usually use mouse tumour-derived scaffolds (Matrigel) or other animal-derived decellularised extracellular matrices as culture systems with poorly defined components and undefined chemical and physical properties, which limit the growth of organoids and the reproducibility of culture conditions. In contrast, some synthetic culture materials have emerged in recent years with well-defined compositions, and flexible adjustment and optimisation of physical and chemical properties, which can effectively support organoid growth and development and prolong survival time of organoid in vitro. In this review, we will introduce the challenge of animal-derived decellularised extracellular matrices in organoid culture, and summarise the categories of biomimetic hydrogels currently used for organoid culture, and then discuss the future opportunities and perspectives in the development of advanced hydrogels in organoids. We hope that this review can promote academic communication in the field of organoid research and provide some assistance in advancing the development of organoid cultivation technology.


Asunto(s)
Biomimética , Hidrogeles , Ratones , Animales , Hidrogeles/farmacología , Hidrogeles/química , Reproducibilidad de los Resultados , Organoides
9.
Front Psychol ; 14: 1153809, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37333598

RESUMEN

As social animals, humans are unique to make the world function well by developing, maintaining, and enforcing social norms. As a prerequisite among these norm-related processes, learning social norms can act as a basis that helps us quickly coordinate with others, which is beneficial to social inclusion when people enter into a new environment or experience certain sociocultural changes. Given the positive effects of learning social norms on social order and sociocultural adaptability in daily life, there is an urgent need to understand the underlying mechanisms of social norm learning. In this article, we review a set of works regarding social norms and highlight the specificity of social norm learning. We then propose an integrated model of social norm learning containing three stages, i.e., pre-learning, reinforcement learning, and internalization, map a potential brain network in processing social norm learning, and further discuss the potential influencing factors that modulate social norm learning. Finally, we outline a couple of future directions along this line, including theoretical (i.e., societal and individual differences in social norm learning), methodological (i.e., longitudinal research, experimental methods, neuroimaging studies), and practical issues.

10.
Biology (Basel) ; 12(6)2023 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-37372054

RESUMEN

This study investigated the effects of NH3-N on antioxidant responses, histoarchitecture, and immunity of Japanese seabass (Lateolabrax japonicus) during keep-live transport. The findings suggest that NH3-N stress transport alters the transcription of P53, Caspase 9, Bcl2, Caspase 3 and Bax genes, demonstrating that NH3-N stress can trigger the apoptotic pathway of P53-Bax-Bcl2 and Caspase and induce apoptosis. NH3-N stress transport also evoked transcriptional upregulation of inflammatory cytokines (tumor necrosis factor α (TNF-α), Toll-like receptor 3 (TLR-3), nuclear factor kappa ß (NF-κB), interleukin 6 (IL-6) and interleukin 1ß (IL-1ß)) and increased complement C3, C4, lysozyme (LZM) and immunoglobulin (IgM) levels, activating the innate immunological system during keep-live transport. In addition, NH3-N stress transport altered changes in the levels of superoxide dismutase (SOD), catalase (CAT), glutathione-related enzymes, and heat shock proteins 70 and 90 in the liver, indicating that the antioxidant system and Hsp protected the cells from NH3-N-induced oxidative stress. When excess ROS were not removed, they caused the body to respond with immunological and inflammatory responses, as well as apoptosis and tissue damage. This helps towards understanding the effect of NH3-N levels on sea bass during keep-live transport.

11.
Food Chem X ; 18: 100709, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37252209

RESUMEN

Post-mortem muscle biochemical processes play a crucial role on fish fillets quality and they are strictly linked to stunning methods. The improper stunning methods before slaughter could cause the fish to deteriorate more quickly during cold storage. This study aimed to investigate the effect of stunning methods (hit on the head, T1; gill cut, T2; immersion in ice/water slurry, T3; CO2 narcosis, T4; 40% CO2 + 30 % N2 + 30% O2, T5) on myofibrillar proteins (MPs) of large yellow croaker. The results indicated that T2 and T3 samples were significantly damaged compared with other samples, which reflected that the activities of total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were significantly damaged during cold storage in T2 and T3 samples. And the gill cut and immersion in ice/water slurry resulted in the generation of protein carbonyl, the decrease of Ca2+-ATPase, free ammonia and protein solubility, and the production of dityrosine during storage. In addition, MPs gel of T2 and T3 samples showed the decrease of water hold capacity (WHC) and whiteness, structure destruction, and water migration. The T4 samples had the least damage of MPs and gel structure during cold storage.

12.
Vet Res Commun ; 47(4): 1879-1891, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37171556

RESUMEN

This study aimed to investigate the effects of different slaughter methods (immersion in ice/water slurry, T1; gill cut, T2; CO2 asphyxia, T3; percussion (hit on the head with a stick), T4; Melissa officinalis L. essential oil + CO2, T5) on physiological stress, oxidative stress, and muscle quality in large yellow croaker. In terms of physiological stress, the levels of glucose (GLU), lactate dehydrogenase (LDH), and catalase (CAT) in CO2 asphyxia samples were significantly lower than those in other samples (p < 0.05). The level of cortisol (COR) in T1 sample was 1.25-1.84 times higher than that of other samples. The GLU level of T1 group was 3.2 times higher than that of T3 sample, and significantly higher than that of other samples. The creatine phosphokinase (CPK) and CAT levels of T2 samples were the highest (2.03 ng/mL and 8.34 U/mL, respectively). Furthermore, the superoxide dismutase (SOD) and glutathione peroxidase (GPx) analysis revealed that T3 and T4 samples could maintain good antioxidant enzyme activity during cold storage. The T3 samples maintained the stability of the protein (the lowest carbonyls and surface hydrophobicity) and reduced lipid oxidation (lower TBARS). In addition, the analysis of pH and water-holding capacity (WHC) revealed that T3 samples had better muscle quality. The muscle of T2 samples kept better color due to bloodletting treatment. The samples obtained after addition of Melissa officinalis L. essential oil had poorer indexes in all aspects compared to the T3 samples, which might be caused by the long anesthesia time of the essential oil.


Asunto(s)
Aceites Volátiles , Perciformes , Animales , Asfixia/veterinaria , Dióxido de Carbono/metabolismo , Indicadores de Calidad de la Atención de Salud , Antioxidantes/farmacología , Perciformes/metabolismo , Aceites Volátiles/farmacología , Aceites Volátiles/metabolismo , Agua/metabolismo
13.
Biology (Basel) ; 12(2)2023 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-36829501

RESUMEN

This study aimed to evaluate the effect of different transport densities on water deterioration, physiological response, nutrients, and fresh quality of sea bass (Lateolabrax maculatus) at 30 mg/L tricaine methanesulphonate (MS-222) before and after simulated live transport. The results indicated that the addition of MS-222 could effectively decrease mortality compared with the control (CK) sample during the simulated live transport. The concentration of dissolved oxygen was lower and the total ammonia nitrogen was higher in the high transport density samples than those of low transport density samples after 72 h in transport. The level of blood cortisol (COR), glucose (GLU), lactic acid (LD), aspartate aminotransferase (AST), alanine aminotransferase (ALT) for the sea bass were significantly higher compared with the CK sample (p < 0.05) during the simulated live transport and after 12 h of recovery. These results indicated that the sea bass presented a strong stress response in high-density transport. The glycogen, fat, and protein of the sea bass were degraded to supply the energy for the body in the process of surviving the transportation, resulting in the decreased nutrient content in the muscle, which recovered to the initial level (CK) after 12 h. The increase in flavor substance content, such as free amino acids, nucleotides, organic acids, and minerals, enhanced the special flavor of the muscle during the simulated live transport. This study demonstrates that the addition of MS-222 at 30 mg/L to the transport water is an effective method for live fish to realize low mortality and physiological response during high-density and long-distance transport.

14.
FEBS J ; 290(3): 855-871, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36152022

RESUMEN

The modification of chromatin by histone deacetylases (HDACs) has critical roles in transcriptional regulation. In this study, we identified the Rpd3 HDAC complex component Pho23 in Candida albicans and explored its role in the transcriptional regulation of physiological processes. PHO23 deletion increased autophagic activity and upregulated the transcription of ATG genes. Moreover, the deletion of PHO23 severely impaired cell wall stress resistance and reduced the cell wall integrity (CWI) pathway in response to cell wall stress. Furthermore, the pho23Δ/Δ mutant had partial defects in hyphal development and protease secretion, which were associated with the downregulation of genes involved in hyphal development (e.g. HWP1, ALS3 and ECE1) and genes encoding secreted aspartic proteases (e.g. SAP4, SAP5, SAP6 and SAP9). In addition, the deletion of PHO23 strongly attenuated systemic infection and kidney fungal burden in mice, demonstrating that Pho23 is required for the virulence of C. albicans. Together, our results revealed that Pho23 regulates many key physiological processes in C. albicans at the transcriptional level. These data also shed light on the potential for exploiting Rpd3 HDAC complex-related proteins as antifungal targets.


Asunto(s)
Candida albicans , Proteínas Fúngicas , Ratones , Animales , Candida albicans/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Virulencia/genética , Autofagia/genética , Pared Celular/genética , Pared Celular/metabolismo , Regulación Fúngica de la Expresión Génica
15.
Res Microbiol ; 174(3): 103996, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36328097

RESUMEN

The unfolded protein response (UPR) is an important pathway to prevent endoplasmic reticulum (ER) stress in eukaryotic cells. In Saccharomyces cerevisiae, Ire1 is a key regulatory factor required for HAC1 gene splicing for further production of functional Hac1 and activation of UPR gene expression. Autophagy is another mechanism involved in the attenuation of ER stress by ER-phagy, and Atg8 is a core protein in autophagy. Both autophagy and UPR are critical for ER stress response, but whether they act individually or in combination in Candida albicans is unknown. In this study, we explored the interaction between Ire1 and the autophagy protein Atg8 for the ER stress response by constructing the atg8Δ/Δire1Δ/Δ double mutant in the pathogenic fungus C. albicans. Compared to the single mutants atg8Δ/Δ or ire1Δ/Δ, atg8Δ/Δire1Δ/Δ exhibited much higher sensitivity to various ER stress-inducing agents and more severe attenuation of UPR gene expression under ER stress. Further investigations showed that the double mutant had a defect in ER-phagy, which was associated with attenuated vacuolar fusion under ER stress. This study revealed that Ire1 and Atg8 in combination function in the activation of the UPR and ER-phagy to maintain ER homeostasis under ER stress in C. albicans.


Asunto(s)
Autofagia , Candida albicans , Estrés del Retículo Endoplásmico , Proteínas Fúngicas , Autofagia/genética , Familia de las Proteínas 8 Relacionadas con la Autofagia/genética , Familia de las Proteínas 8 Relacionadas con la Autofagia/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Candida albicans/fisiología , Estrés del Retículo Endoplásmico/genética , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Represoras/genética , Respuesta de Proteína Desplegada , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
16.
Sci Adv ; 8(42): eadc9022, 2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36260680

RESUMEN

Wilson disease (WD) is a metabolic disorder caused by inactivation of the copper-transporting ATPase 2 (ATP7B) and copper (Cu) overload in tissues. Excess Cu causes oxidative stress and pathologic changes with poorly understood mechanistic connections. In Atp7b-/- mice with established liver disease, Cu overload activates the stress-sensitive transcription factor Nrf2 (nuclear factor erythroid-derived 2-like 2). Nrf2 targets, especially sulfotransferase 1e1 (Sult1e1), are strongly induced and cause elevation of sulfated sterols, whereas oxysterols are decreased. This sterol misbalance results in inhibition of the liver X receptor (LXR) and up-regulation of LXR targets associated with inflammatory responses. Pharmacological inhibition of Sult1e1 partially reverses oxysterol misbalance and LXR inhibition. Contribution of this pathway to advanced hepatic WD was demonstrated by treating mice with an LXR agonist. Treatment decreased inflammation by reducing expression of proinflammatory molecules, diminished fibrosis by down-regulating the noncanonical transforming growth factor-ß signaling pathway, and improved liver morphology and function. Thus, the identified pathway is an important driver of WD.

17.
Chemosphere ; 307(Pt 2): 135818, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35944684

RESUMEN

Metallothionein SmtA-modified selenium nanoparticles (SmtA-SeNPs), efficient adsorbents for Cd(II) and Pb(II), were synthesized in the present work. The ligand, microbial SmtA protein, was synthesized using an engineered strain Escherichia coli, posing the benefits of simplicity, safety, and high production. SmtA-SeNPs were spheres with diameters between 68.1 and 122.4 nm, containing amino, hydroxyl, and sulfhydryl functional groups with negatively charged (pH > 5). SmtA-SeNPs displayed better adsorption performance than dissociative SmtA and SeNPs. The adsorption of Cd(II) and Pb(II) mainly depends on the electrostatic attractions and the metal chelation of abundant functional groups. The maximum adsorption capacity was 506.3 mg/g for Cd(II) and 346.7 mg/g for Pb(II), which were higher than the values of most nanoparticles. In addition, SmtA-SeNPs were immobilized with a membrane filter to produce a SmtA-SeNPs filter, and the percentage removal of Cd(II) and Pb(II) increased from 26.75% to 98.13% for Cd(II) and from 9.95% to 99.20% compared with the blank filter. Moreover, the SmtA-SeNPs filter was regenerated using subacid deionized water, and the filter exhibited a stable removal ratio of Cd(II) and Pb(II) in ten continuous cycles of Cd(II)- or Pb(II)-containing wastewater treatment. The residual amounts of Cd and Pb met national standard levels of wastewater discharge.


Asunto(s)
Nanopartículas , Selenio , Contaminantes Químicos del Agua , Adsorción , Cadmio/análisis , Plomo , Ligandos , Metalotioneína/metabolismo , Aguas Residuales/química , Agua , Contaminantes Químicos del Agua/análisis
18.
Procedia Comput Sci ; 202: 55-60, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35574223

RESUMEN

At the beginning of 2020, COVID-19 began to sweep through China, major schools adhering to the concept of "no classrooms instead of classes" and launching online education. The major online education platforms received the "epidemic advantage" and grew. However, on the night of 24 July 2021, when Chinese authorities have introduced a guideline to ease the burdens of excessive homework and off-campus tutoring for students undergoing compulsory education, so that including online education platforms, received a severe blow. As part of the digital economy, the current transformation of the education sector to education informatization, quality education and vocational education may become the vane of the new era.

19.
Front Microbiol ; 13: 834293, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35350625

RESUMEN

A ferredoxin protein (AAY72_06850, named FesR) was identified to associate with chromate [Cr(VI)] resistance in Alishewanella sp. WH16-1. FesR and its similar proteins were phylogenetically separated from other reductase families. Unlike the reported Cr(VI) and selenite [Se(IV)] reductases, two 4Fe-4S clusters and one flavin adenine dinucleotide (FAD) -binding domain were found in the FesR sequence. The experiment in vivo showed that the mutant strain ΔfesR had lost partial Cr(VI) and Se(IV) reduction capacities compared to the wild-type and complemented strains. Furthermore, overexpression in Escherichia coli and enzymatic tests in vitro showed FesR were involved in Cr(VI) and Se(IV) reduction. 4Fe-4S cluster in purified FesR was detected by ultraviolet-visible spectrum (UV-VIS) and Electron Paramagnetic Resonance (EPR). The Km values of FesR for Cr(VI) and Se(IV) reduction were 1682.0 ± 126.2 and 1164.0 ± 89.4 µmol/L, and the Vmax values for Cr(VI) and Se(IV) reduction were 4.1 ± 0.1 and 9.4 ± 0.3 µmol min-1 mg-1, respectively. Additionally, site-directed mutagenesis and redox potential analyses showed that 4Fe-4S clusters were essential to FesR, and FAD could enhance the enzyme efficiencies of FesR as intracellular electron transporters. To the best of our knowledge, FesR is a novel Cr(VI) and Se(IV) reductase.

20.
J Hazard Mater ; 425: 127919, 2022 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-34894511

RESUMEN

In this study, we isolated a highly cadmium (Cd)-resistant bacterium, Pseudomonas sp. B7, which immobilized 100% Cd(II) from medium. Culturing strain B7 with Cd(II) led to the change of functional groups, mediating extracellular Cd(II) adsorption. Proteomics showed that a carbonic anhydrase, CadW, was upregulated with Cd(II). CadW expression in Escherichia coli conferred resistance to Cd(II) and increased intracellular Cd(II) accumulation. Fluorescence assays demonstrated that CadW binds Cd(II) and the His123 residue affected Cd(II) binding activity, indicating that CadW participates in intracellular Cd(II) sequestration. Chinese cabbage pot experiments were performed using strain B7 and silicate [Si(IV)]. Compared with the control, Cd content in aboveground parts significantly decreased by 21.3%, 29.4% and 32.9%, and nonbioavailable Cd in soil significantly increased by 129.4%, 45.0% and 148.7% in B7, Si(IV) and B7 +Si(IV) treatments, respectively. The application of Si(IV) alone reduced chlorophyll content by 20.8% and arylsulfatase activity in soil by 33.9%, and increased malonaldehyde activity by 15.0%. The application of strain B7 alleviated the negative effect of Si(IV) on plant and soil enzymes. Overall, application of Si(IV) is most conducive to the decreased Cd accumulation in plant, and strain B7 is beneficial to maintaining soil and plant health.


Asunto(s)
Cadmio , Contaminantes del Suelo , Adsorción , Cadmio/análisis , Pseudomonas , Suelo , Contaminantes del Suelo/análisis
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