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BACKGROUND AND PURPOSE: Whilst retinal microvasculature represents cerebral small vessels, the retinal nerve fiber layer is the extended white matter of the brain. The aim was to investigate the correlation between changes in retina and white matter hyperintensities (WMHs). METHODS: Sixty-four candidates with WMHs received an optical coherence tomography angiography examination. WMHs were divided into mild or moderate/severe groups according to the Fazekas score. After imaging the superficial capillary plexus (SCP) and deep capillary plexus (DCP), the microvascular density parameters (vascular perfusion density [VPD], vascular length density [VLD] and fovea avascular zone area) and morphological parameters (vessel diameter index [VDI], fractal dimension [FD] and vessel tortuosity) were identified. A software algorithm measured the thickness of the peripapillary retina nerve fiber layer (PRNFL). RESULTS: Thirty-two were classified as having mild WMHs and 32 were moderate/severe. The median (interquartile range) ages of the two groups were 58 (54-64) and 61 (57-67) years, respectively. A decrease of FD, VPD and VLD in either SCP or DCP appeared with an increased risk of moderate/severe WMHs. Although changes of capillary plexus were not associated with paraventricular WMHs, decreased FD, VPD, VLD and fovea avascular zone area in either SCP or DCP were associated with an increased risk of moderate/severe deep WMHs (DWMHs). Participants with moderate/severe WMHs demonstrated reduced PRNFL thickness, particularly in the DWMHs, compared with mild WMHs. CONCLUSIONS: Abnormalities of retinal microvascular density, morphological parameters and PRNFL thickness are correlated with the incidence of moderate/severe WMHs, particularly the DWMHs, suggesting that arteriosclerosis and hypoperfusion are the causes of DWMHs.
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Vasos Retinianos , Sustancia Blanca , Angiografía con Fluoresceína/métodos , Humanos , Microvasos/diagnóstico por imagen , Retina/diagnóstico por imagen , Vasos Retinianos/diagnóstico por imagen , Tomografía de Coherencia Óptica/métodos , Sustancia Blanca/diagnóstico por imagenRESUMEN
Understanding the relationship between air quality, pollution emission control measures, and meteorological conditions is important for developing effective air quality improvement policies. In this study, we used pollution monitoring and meteorological data from January to May 2020 to analyze the air quality characteristics during the COVID-19 lockdown in Wuhan, which lasted from January 23 to April 8, 2020. Compared with the same period in 2019, the air quality in 2020 was significantly better. The total excellent and good air quality rates increased by 17.58%-90.08% in 2020; concentrations of NO2, particulate matter with a diameter <10 µm (PM10) and <2.5 µm (PM2.5), and total volatile organic compounds (TVOCs) also decreased by 38.23%, 30.25%, 32.92%, and 39.80%, respectively. Moreover, the number of days with NO2, PM10, and PM2.5 as the primary pollutants decreased by approximately 10%, 9%, and 15%, respectively. We compared the wind direction, wind speed, temperature, and relative humidity in January-April 2020, 2019, 2018, and 2017 and found no obvious correlation between meteorological factors and improved air quality during the 2020 lockdown. The implementation of strict lockdown measures, such as home quarantining, traffic restrictions, and non-essential enterprise shutdowns, was the dominant cause for the substantial air quality improvement during the 2020 COVID-19 lockdown in Wuhan.
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Contaminantes Atmosféricos , Contaminación del Aire , COVID-19 , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , China , Ciudades , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Humanos , Pandemias , Material Particulado/análisis , SARS-CoV-2RESUMEN
Heat shock protein 90 (Hsp90), as a member of the Hsp family and widely found in the gonads of humans and animals, plays an essential role in male reproduction and induces various changes in the process of reproduction. Hsp90 regulates the division of germ cells and participates in spermatogenesis, location of germ cells, formation of sperm microtubes, protection of sperm from oxidative stress, and inducement of acrosomal reaction. Studies showed significant changes in location and expression of Hsp90 in the sperm of oligospermia and asthenospermia patients. This paper presents an overview of Hsp90 in male reproduction and male infertility and a prospect of the treatment of male infertility.
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Proteínas de Choque Térmico , Humanos , MasculinoRESUMEN
Pressure ulcer is a complex and significant health problem in long-term bedridden patients, and there is currently no effective treatment or efficient prevention method. Furthermore, the molecular mechanisms and pathogenesis contributing to the deep injury of pressure ulcers are unclear. The aim of the study was to explore the role of endoplasmic reticulum (ER) stress and Akt/GSK3ß signaling in pressure ulcers. A model of pressure-induced deep tissue injury in adult Sprague-Dawley rats was established. Rats were treated with 2-h compression and subsequent 0.5-h release for various cycles. After recovery, the tissue in the compressed regions was collected for further analysis. The compressed muscle tissues showed clear cellular degenerative features. First, the expression levels of ER stress proteins GRP78, CHOP, and caspase-12 were generally increased compared to those in the control. Phosphorylated Akt and phosphorylated GSK3ß were upregulated in the beginning of muscle compression, and immediately significantly decreased at the initiation of ischemia-reperfusion injury in compressed muscles tissue. These data show that ER stress may be involved in the underlying mechanisms of cell degeneration after pressure ulcers and that the Akt/GSK3ß signal pathway may play an important role in deep tissue injury induced by pressure and ischemia/reperfusion.
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Estrés del Retículo Endoplásmico , Músculo Esquelético/metabolismo , Úlcera por Presión/metabolismo , Daño por Reperfusión/metabolismo , Animales , Caspasa 12/genética , Caspasa 12/metabolismo , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Masculino , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/patología , Úlcera por Presión/etiología , Úlcera por Presión/patología , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/complicaciones , Daño por Reperfusión/patología , Transducción de Señal , Factor de Transcripción CHOP/genética , Factor de Transcripción CHOP/metabolismo , Regulación hacia ArribaRESUMEN
Lately, emulsions with low-fat and natural stabilizers are predominant. This study extracted the nano cellulose crystals (NCs) from Camellia Oleifera shells, and their gallic acid (GA) conjugates were synthesized by free-radical grafting. Pickering emulsions were prepared using NCs 1â¯%, 1.5â¯%, 2.5â¯%, and gallic acid conjugates NC-GA1, NC-GA2, and NC-GA3 as stabilizers. The obtained nano cellulose crystals exhibited 18-25â¯nm, -40.01⯱â¯2.45 size, and zeta potential, respectively. The contact angle of 83.4° was exhibited by NC-GA3 conjugates. The rheological, interfacial, and microstructural properties and stability of the Pickering emulsion were explored. NC-GA3 displayed the highest absorption content of 79.12â¯%. Interfacial tension was drastically reduced with increasing GA concentration in NC-GA conjugates. Rheological properties suggested that the low-fat NC-GA emulsions showed a viscoelastic behavior, increased viscosity, gel-like structure, and increased antioxidant properties. Moreover, NC-GA3 displayed reduced droplet size and improved emulsion temperature and storage stability (28â¯days) against phase separation. POV and TBARS values were reduced with the NC-GA3 (Pâ¯<â¯0.05). This work confirmed that grafting phenolic compounds on NCs could enhance bioactive properties, which can be used in developing low-fat functional foods. NC-GA conjugates can potentially fulfill the increasing demand for sustainable, healthy, and low-fat foods.
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Antioxidantes , Camellia , Celulosa , Emulsiones , Ácido Gálico , Reología , Camellia/química , Ácido Gálico/química , Celulosa/química , Antioxidantes/química , Viscosidad , Nanopartículas/química , CristalizaciónRESUMEN
Underwater light attenuation leads to decreased image contrast. This reduction in contrast subsequently decreases target visibility. Additionally, marine target detection is challenging due to multi-scale problems from varying target-to-device distances, complex target clustering, and noise from waterborne particulates.To address these issues, we propose MTD-YOLOv5.Initially, we enhance image contrast with grayscale equalization and mitigate color shift issues through color space transformation.We then introduce a novel feature extraction module, PCBR, combining max pooling and convolution layers for more effective target feature extraction from the background.Furthermore, we present the Multi-Scale Perceptual Hybrid Pooling (MHP) module.This module integrates horizontal and vertical receptive fields to establish long-range dependencies, thereby capturing hidden target information in deep network feature maps. In the Labeled Fishes in the Wild test datasets, MTD-YOLOv5 achieves a precision of 88.1% and a mean Average Precision (mAP[0.5:.95]) of 49.6%.These results represent improvements of 2.6% in precision and 0.4% in mAP over the original YOLOv5.
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Chronic kidney disease (CKD) poses a significant global health dilemma, emerging from complex causes. Although our prior research has indicated that a deficiency in Reticulon-3 (RTN3) accelerates renal disease progression, a thorough examination of RTN3 on kidney function and pathology remains underexplored. To address this critical need, we generated Rtn3-null mice to study the consequences of RTN3 protein deficiency on CKD. Single-cell transcriptomic analyses were performed on 47,885 cells from the renal cortex of both healthy and Rtn3-null mice, enabling us to compare spatial architectures and expression profiles across 14 distinct cell types. Our analysis revealed that RTN3 deficiency leads to significant alterations in the spatial organization and gene expression profiles of renal cells, reflecting CKD pathology. Specifically, RTN3 deficiency was associated with Lars2 overexpression, which in turn caused mitochondrial dysfunction and increased reactive oxygen species levels. This shift induced a transition in renal epithelial cells from a functional state to a fibrogenic state, thus promoting renal fibrosis. Additionally, RTN3 deficiency was found to drive the endothelial-to-mesenchymal transition process and disrupt cell-cell communication, further exacerbating renal fibrosis. Immunohistochemistry and Western-Blot techniques were used to validate these observations, reinforcing the critical role of RTN3 in CKD pathogenesis. The deficiency of RTN3 protein in CKD leads to profound changes in cellular architecture and molecular profiles. Our work seeks to elevate the understanding of RTN3's role in CKD's narrative and position it as a promising therapeutic contender.
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Progresión de la Enfermedad , Fibrosis , Perfilación de la Expresión Génica , Insuficiencia Renal Crónica , Análisis de la Célula Individual , Animales , Ratones , Fibrosis/patología , Fibrosis/metabolismo , Fibrosis/genética , Insuficiencia Renal Crónica/genética , Insuficiencia Renal Crónica/patología , Insuficiencia Renal Crónica/metabolismo , Ratones Noqueados , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Riñón/patología , Riñón/metabolismo , Transcriptoma , Especies Reactivas de Oxígeno/metabolismo , Transición Epitelial-Mesenquimal/genética , Modelos Animales de Enfermedad , Mitocondrias/metabolismo , Mitocondrias/patología , Mitocondrias/genéticaRESUMEN
Developing a highly effective nano-drug delivery system with sufficient drug permeability and retention in tumors is still a major challenge for oncotherapy. Herein, a tumor microenvironment responsive, aggregable nanocarriers embedded hydrogel (Endo-CMC@hydrogel) was developed to inhibit the tumoral angiogenesis and hypoxia for enhanced radiotherapy. The antiangiogenic drug (recombinant human endostatin, Endo) loaded carboxymethyl chitosan nanoparticles (Endo-CMC NPs) was wrapped by 3D hydrogel to comprise the Endo-CMC@hydrogel. After peritumoral injection, the Endo-CMC NPs were released, invaded deeply into the solid tumor, and cross-linked with intratumoral calcium ions. The cross-linking process enabled these Endo-CMC NPs to form larger particles, leading to long retention in tumor tissue to minimize premature clearance. This Endo-CMC@hydrogel, integrating the abilities of good tumoral penetration, long retention of anti-drug, and alleviation of hypoxia in tumor tissue, greatly improved the therapeutic effect of radiotherapy. This work provides a proof-of-concept of tumor microenvironment-responding and an aggregable nano-drug delivery system as promising antitumor drug carriers for effective tumor therapy.
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Antineoplásicos , Quitosano , Nanopartículas , Humanos , Antineoplásicos/administración & dosificación , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Quitosano/administración & dosificación , Portadores de Fármacos , Hidrogeles , Sistema de Administración de Fármacos con NanopartículasRESUMEN
Our previous studies have shown that the baicalin could blocked infection of chlamydia trachomatis (C. trachomatis)-infected cells in vitro. Toll-like receptor 2 and 4 (TLR2/4) and the downstream nuclear factor-κB (NF-κB) signaling pathway, which mediate the inflammatory reaction, are involved in the pathophysiological processes of inflammation. In this study, we investigated whether baicalin inhibits TLR2/4 signaling pathway in gential tract chlamydia-infected mice. The progesterone-treated animals were given intravaginally 200 mg/kg baicalin administered. Nineteen days after infection, cervical tissue were taken and expression of TLR2/4, NF-κB were determined by RT-PCR or westernblot. Nitric oxide and prostaglandin E2 production in cervical tissue were detected by enzyme-linked immunosorbent assay. It was demonstrated that baicalin significantly reduced C. trachomatis loading in BALB/c mice that were vaginally infected with the pathogen. Meanwhile, baicalin also reduced the expression of TLR2/4 and NF-κB, decreased activity of inducible nitric oxide synthase and cyclooxgenase-2 in cervical tissue. Our results suggest that baicalin inhibits the TLR2/4 signaling pathway in cervical tissue of gential tract chlamydia-infected mice. On the basis of these data and our previous observations, we conclude that further evaluation of baicalin for prevention and treatment of sexually transmitted chlamydial infection is warranted.
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Antiinfecciosos/farmacología , Chlamydia trachomatis , Flavonoides/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Linfogranuloma Venéreo/tratamiento farmacológico , FN-kappa B/metabolismo , Receptor Toll-Like 2/biosíntesis , Receptor Toll-Like 4/biosíntesis , Animales , Línea Celular , Línea Celular Tumoral , Cuello del Útero/metabolismo , Cuello del Útero/microbiología , Ciclooxigenasa 2/biosíntesis , Dinoprostona/biosíntesis , Femenino , Humanos , Linfogranuloma Venéreo/metabolismo , Ratones , Óxido Nítrico Sintasa de Tipo II/biosíntesis , Transducción de Señal/efectos de los fármacosRESUMEN
Objective: Low heart rate variability (HRV), an indicator of autonomic nervous system dysfunction, has been associated with increased all-cause and cardiovascular mortality and incident stroke. However, the relationship between HRV and cerebral small vessel disease (CSVD) showed contradictory results. We aimed to examine the relationship of HRV and total burden of CSVD and each of the magnetic resonance imaging (MRI) markers of CSVD. Methods: We recruited 435 patients who attended our hospital for physical examination between June 2020 and August 2021. All underwent 24-h Holter monitoring and MRI scan. The standard deviation of normal-to-normal intervals (SDNN) was selected as the method for HRV assessment. The presence of severe white matter hyperintensity, lacunes, and >10 enlarged basal ganglia perivascular spaces, and cerebral microbleeds were added for estimating the CSVD score (0-4). Multivariate logistic analyses was performed to assess whether HRV was independently associated with the burden of CSVD and each of the MRI markers of CSVD, with and without stratification by prevalent diabetes. Results: This study included 435 subjects with a mean age of 64.0 (57.0-70.0) years; 49.4% of the patients were male, and 122 (28.0%) had a history of diabetes. In multivariate analyses, lower SDNN was independently associated with total burden of CSVD and the presence of enlarged perivascular spaces in all subjects. According to diabetes stratification, lower SDNN was independently associated with total burden of CSVD and each MRI markers of CSVD separately only in the diabetic group. Conclusions: Lower HRV was associated with total burden of CSVD and each MRI markers of CSVD separately among diabetic patients, but not among non-diabetic patients.
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This study investigated the effect of the extract of Bupleuri Radix (BRE) on the infection of Madin-Darby Canine Kidney (MDCK) cells by anti-H1N1 virus. The effect of BRE on RANTES (the chemokine regulated on activation, normal T cells expressed and secreted) secretion in H1N1-infected A549 cells (human bronchial epithelial cells) was evaluated via quantative measurement of the changes in the cytopathic effects and by the ultraviolet (UV) absorbance at 600 nm. It was found that BRE was toxic to MDCK cells at a higher concentration while had a marked inhibitory effect on cell pathological changes at a lower concentration. Results also showed that BRE possessed more than 50% suppressing effect on RANTES secretion in H1N1-infected A549 cells at a concentration of 100 and 200 µg/ml. Our findings show that BRE has a significant protective effect on MDCK cells infected in a dose-dependent manner with an excellent suppressing effect on RANTES secretion, suggesting that BRE can be developed as an antivirus agent.
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Antivirales/farmacología , Subtipo H1N1 del Virus de la Influenza A/fisiología , Gripe Humana/tratamiento farmacológico , Extractos Vegetales/farmacología , Animales , Bronquios/efectos de los fármacos , Bronquios/metabolismo , Bronquios/patología , Bronquios/virología , Bupleurum , Línea Celular , Línea Celular Tumoral , Quimiocina CCL5/antagonistas & inhibidores , Efecto Citopatogénico Viral/efectos de los fármacos , Perros , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Células Epiteliales/patología , Células Epiteliales/virología , Frutas/química , Humanos , Gripe Humana/metabolismo , Gripe Humana/patología , Gripe Humana/virologíaRESUMEN
Baicalin has emerged as a promising agent for the therapy of infectious diseases due to the increasing number of pathogenic microbial strains resistant to several antibiotics. In this study, we investigated the inhibitory activity of baicalin on Chlamydia infection in vitro. We found that baicalin blocked the infection of HeLa cells in vitro when added to the infected cells. In order to shed light on the inhibitory effects of baicalin on the Chlamydia-infected cells, the expression of RFX5 and Chlamydia protease-like activity factor (CPAF) mRNAs and proteins in the Chlamydia-infected cells were examined using Western blot and real-time RT-PCR analysis. The results demonstrated that RFX5 and CPAF were upregulated and downregulated, respectively, by baicalin. Because CPAF is responsible for degrading RFX5, it is suggested that CPAF is a primary target of baicalin and plays an important role in downregulating RFX5. In conclusion, our findings demonstrated that baicalin can effectively inhibit Chlamydia Trachomatis in HeLa cells and therefore can be considered a potential agent for the therapy of infectious diseases caused by C. trachomatis.
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Antibacterianos/uso terapéutico , Infecciones por Chlamydia/prevención & control , Chlamydia trachomatis/efectos de los fármacos , Medicamentos Herbarios Chinos/uso terapéutico , Flavonoides/uso terapéutico , Fitoterapia , Scutellaria baicalensis/química , Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Western Blotting , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Regulación hacia Abajo , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Flavonoides/farmacología , Células HeLa , Humanos , ARN Mensajero/metabolismo , Factores de Transcripción del Factor Regulador X , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
In the present paper we report the results obtained with the photosystem II (PSII) isolated from spinach treated by MgCl(2), and studied the effect of Mg(2+) on spectral characteristics and photosynthetic functions of PSII. The results showed that Mg(2+) treatment at a suitable concentration could significantly increase the absorption intensity of PSII and the intensity ratio of Soret band to Q band of chlorophyll-a. The treatment also elevated the excited peak intensity at 230, 278 and 343 nm, and the emitted peak intensity at 304 and 682 nm, and the ratio of F(278)/F(230), respectively. The results implied that Mg(2+) increased absorbance for visible light, improving energy transfer among amino acids within PSII protein complex and accelerating energy transport from tyrosine residue to chlorophyll-a. The photochemical activity and oxygen evolving rate of PSII were also enhanced by Mg(2+). This is viewed as evidence that Mg(2+) can promote energy transfer and oxygen evolution in PSII of spinach.
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Cloruro de Magnesio/química , Fotosíntesis , Complejo de Proteína del Fotosistema II/química , Spinacia oleracea , Clorofila/química , Clorofila A , Transporte de Electrón , Proteínas de Plantas/química , Análisis Espectral/métodos , Spinacia oleracea/química , Spinacia oleracea/metabolismoRESUMEN
In this work, 0-dimensional (0D) CsPbBr3 QDs were integrated with 2D bismuthene having ultrafast carrier mobility, to obtain a 0D/2D nanohybrid. Moreover, an excellent charge transfer efficiency (0.53) and an appreciable quenching constant of 2.3 × 105 M-1 were observed. Tuning the ratio of bismuthene in the Bi/perovskite nanohybrid achieved the quantified control of charge transfer efficiency and quenching performance at the interface.
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BACKGROUND: We redesigned decompressive craniectomy and cranioplasty procedures to decrease the inherent risk of complications. This novel technique, called decompressive cranioplasty, not only may decrease the complication rate but also may improve the cosmetic result, obviate the need for artificial skull implant, and increase the decompressive volume compared with traditional craniectomy. METHODS: In decompressive cranioplasty, the Agnes Fast craniotomy was adopted without cutting the temporalis muscle from the underlying bone flap. After opening the dura with or without removal of intracranial hematomas, duraplasty was performed with an intracranial pressure monitor inserted. Four miniplates were bent into a "Z" shape, and the vascularized bone flap was elevated approximately 1.2-1.5 cm above the outer cortex of the skull and fixed with the miniplates. Subsequent cranioplasty was done with a mini-incision on the miniplate sites and reshaping of the miniplate to align the outer cortex of the bone flap. RESULTS: We successfully performed decompressive cranioplasty in 3 emergent cases-2 traumatic subdural hematomas and 1 malignant middle cerebral artery infarction. Postoperative brain computed tomography demonstrated adequate decompression in all cases. Cosmetic outcome was excellent, and there was no temporal hallowing. Mastication function was not affected. At 6-month follow-up, there was no bone flap shrinkage and no hydrocephalus. CONCLUSIONS: Decompressive cranioplasty is a safe and effective method in the management of patients with brain edema and intracranial hypertension. It is simple to perform and may reduce the morbidity associated with traditional decompressive craniectomy and subsequent cranioplasty.
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In this research, we developed a novel chimeric HTNV-IL-2-G2 DNA vaccine plasmid by genetically linking IL-2 gene to the G2 segment DNA and tested whether it could be a candidate vaccine. Chimeric gene was first expressed in eukaryotic expression system pcDNA3.1 (+). The HTNV-IL-2-G2 expressed a 72 kDa fusion protein in COS-7 cells. Meanwhile, the fusion protein kept the activity of its parental proteins. Furthermore, BALB/c mice were vaccinated by the chimeric gene. ELISA, cell microculture neutralization test in vitro were used to detect the humoral immune response in immunized BALB/c mice. Lymphocyte proliferation assay was used to detect the cellular immune response.- The results showed that the chimeric gene could simultaneously evoke specific antibody against G2 glycoprotein and IL-2. And the immunized mice of every group elicited neutralizing antibodies with different titers. Lymphocyte proliferation assay results showed that the stimulation indexes of splenocytes of chimeric gene to G2 and IL-2 were significantly higher than that of other groups. Our results suggest that IL-2-based HTNV G2 DNA can induce both humoral and cellular immune response specific for HTNV G2 and can be a candidate DNA vaccine for HTNV infection.
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Mg(2+) in various concentrations was added to purified Rubisco in vitro to gain insight into the mechanism of molecular interactions between Mg(2+) and Rubisco. The enzyme activity assays showed that the reaction between Rubisco and Mg(2+) was two order, which means that the enhancement of Rubisco activity was accelerated by low concentration of Mg(2+) and slowed by high concentration of Mg(2+). The kinetics constant (K (m)) and V (max) was 1.91 microM and 1.13 micromol CO(2) mg(-1) protein.min(-1), respectively, at a low concentration of Mg(2+), and 3.45 microM and 0.32 micromol CO(2)mg(-1) protein.min(-1), respectively, at a high concentration of Mg(2+). By UV absorption and fluorescence spectroscopy assays, the Mg(2+) was determined to be directly bound to Rubisco; the binding site of Mg(2+) to Rubisco was 0.275, the binding constants (K (A)) of the binding site were 6.33 x 10(4) and 5.5 x 10(4) l.mol(-1). Based on the analysis of the circular dichroism (CD) spectra, it was concluded that the binding of Mg(2+) did not alter the secondary structure of Rubisco, suggesting that the observed enhancement of Rubisco carboxylase activity was caused by a subtle structural change in the active site through the formation of the complex with Mg(2+).
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Magnesio/farmacología , Ribulosa-Bifosfato Carboxilasa/química , Ribulosa-Bifosfato Carboxilasa/metabolismo , Dióxido de Carbono/metabolismo , Catálisis/efectos de los fármacos , Dicroismo Circular , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Cinética , Espectrofotometría UltravioletaRESUMEN
The main aim of the study was to determine the role of cerium in the amelioration of calcium-deficiency effects in spinach plants. Spinach plants were cultivated in Hoagland's solution. They were subjected to calcium-deficiency and to cerium chloride administered in the calcium-present Hoagland's media and calcium-deficient Hoagland's media. Within 3 weeks, young leaves developed distinct calcium-deficient symptoms, and plant growth significantly inhibited to calcium deprivation as would be expected; cerium-treated groups grown in the same conditions did not develop calcium-deficient symptoms; fresh weight, dry weight and chlorophyll content of spinach plants were increased by 35.9, 45 and 64.05% compared to those of plants cultivated in calcium-deficient media. In addition, calcium deprivation in spinach plants caused the reduction of photosynthetic rate, oxygen evolution rate and ribulose-1,5-bisphosphate carboxylase/oxygenase activity. The reduction of activities of nitrate reductase, glutamate dehydrogenase, glutamate synthase and glutamic-pyruvic transaminase was observed under calcium-deficient media. However, cerium treatment under calcium-deficient media could significantly improve photosynthesis and nitrogen metabolism of spinach plants. This is viewed as evidence that cerium added to calcium-deficient media in the spinach plants could substitute for calcium and improve spinach growth.
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Calcio/metabolismo , Cerio/farmacología , Spinacia oleracea/efectos de los fármacos , Spinacia oleracea/crecimiento & desarrollo , Clorofila/metabolismo , Oxígeno/metabolismo , Fotosíntesis/efectos de los fármacos , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Ribulosa-Bifosfato Carboxilasa/metabolismo , Spinacia oleracea/metabolismoRESUMEN
A proven photocatalyst, titanium dioxide in the form of nano-anatase, is capable of undergoing electron transfer reactions under light. In previous studies, we had proven that nano-anatase could absorb ultraviolet light (UV-B) and convert light energy to stable chemistry energy finally via electron transport in spinach chloroplasts. The mechanisms by which nano-anatase promotes antioxidant stress in spinach chloroplasts under UV-B radiation are still not clearly understood. In the present paper, we investigate the effects of nano-anatase on the antioxidant stress in spinach chloroplasts under UV-B radiation. The results showed that nano-anatase treatment could significantly decrease accumulation of superoxide radicals O2.-, hydrogen peroxide (H2O2), and malonyldialdehyde (MDA) content, and increase activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and elevate evolution oxygen rate in spinach chloroplasts under UV-B radiation. Together, nano-anatase could decrease the oxidative stress to spinach chloroplast caused by UV-B radiation.
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Antioxidantes/metabolismo , Cloroplastos/efectos de los fármacos , Cloroplastos/efectos de la radiación , Titanio/farmacología , Rayos Ultravioleta , Ascorbato Peroxidasas , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Peroxidasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Spinacia oleraceaRESUMEN
Chloroplasts were isolated from spinach cultured in calcium-deficient, cerium-chloride-administered calcium-present Hoagland's media or that of calcium-deficient Hoagland's media and demonstrated the effects of cerium on distribution of light energy between photosystems II and I and photochemical activities of spinach chloroplast grown in calcium-deficient media. It was observed that calcium deprivation significantly inhibited light absorption, energy transfer from LHCII to photosystemII, excitation energy distribution from PSI to PSII, and transformation from light energy to electron energy and oxygen evolution of chloroplasts. However, cerium treatment to calcium-deficient chloroplasts could obviously improve light absorption and excitation energy distribution from photosystem I to photosystem II and increase activity of whole chain electron transport, photosystems II and I DCPIP photoreduction, and oxygen evolution of chloroplasts. The results suggested that cerium under calcium deficiency condition could substitute for calcium in chloroplasts, maintain the stability of chloroplast membrane, and improve photosynthesis of spinach chloroplast, but the mechanisms still need further study.