This study aimed to investigate the cell cycle arrest and autophagy induced by iron overload in MC3T3‐E1 cells. MC3T3‐E1 cells were cultured in different concentrations of ferric ammonium citrate ...(FAC), and Perls’ Prussian blue reaction was used to detect the iron levels of the cells. CCK‐8 assays were used to detect the growth of MC3T3‐E1. The level of reactive oxygen species (ROS) within cells was investigated with DCFH‐DA. PI staining was used to analyze the cell cycle distribution of MC3T3‐E1 cells. Finally, the expression levels of cell cycle related proteins, autophagy related proteins, AKT, p38 MAPK, Stat3, and their downstream proteins were detected with Western blot assays. The results showed that the iron levels of MC3T3‐E1 cells increased with increasing concentrations of FAC. High levels of ferric ion inhibited proliferation of MC3T3‐E1 cells and increased their ROS levels. Additionally, iron overload induced G1arrest in MC3T3‐E1 cells and down‐regulated the expression of Cyclin D1, Cyclin D3, CDK2, CDK4 and CDK6, but up‐regulated p27 Kip1. In addition, the expression levels of Beclin‐1 and LC3 II increased, but that of p62 decreased. Further experiments showed that the phosphorylation of AKT and its downstream proteins p‐GSK‐3β(Ser9) and p‐mTOR (Ser2448) were decreased. The levels of p‐p38 and p53 were up‐regulated while those of cdc25A and p‐ERK 1/2 were down‐regulated. Phosphorylation of Stat3 and its downstream proteins was all decreased. These results show that iron overload generates ROS, blocks the PI3K/AKT and Jak/Stat3 signal pathways, and activates p38 MAPK, subsequently inducing G1 arrest and autophagy in MC3T3‐E1 cells.
Iron overload generates ROS, blocks the PI3K/AKT and Jak/Stat3 signal pathways, and activates p38 MAPK, subsequently inducing G1 arrest and autophagy in MC3T3‐E1 cells.
Biometric recognition can be used to improve gesture-based interfaces by automatically identifying operators. Traditional palm biometric recognition techniques depend on palm appearance features, but ...these features are not available in an operating theater where gloves are worn. We propose a depth-based solution for palm biometric recognition. Based on the depth image, our system automatically segments the user's palm and extracts finger dimensions. The finger dimensions are further scaled according to the sensed depth to obtain the true finger dimensions, which are then used as features to characterize the palm. Finally, a modified k-nearest neighbors algorithm that assigns class labels based on the centroid displacement of each class in the neighboring points is applied to recognize the palm based on the geometric features. An accuracy of 96.24% was achieved for the biometric recognition of 4057 gloved palm samples captured at different angles and depths from 27 users. This accuracy is comparable with those of other state-of-the-art classification algorithms and demonstrates that biometric recognition may be viable for settings with gloved hands such as surgery.
Abstract
Carbon supported intermetallic compound nanoparticles with high activity and stability are promising cathodic catalysts for oxygen reduction reaction in proton-exchange-membrane fuel cells. ...However, the synthesis of intermetallic catalysts suffers from large diffusion barrier for atom ordering, resulting in low ordering degree and limited performance. We demonstrate a low-melting-point metal doping strategy for the synthesis of highly ordered L1
0
-type M-doped PtCo (M = Ga, Pb, Sb, Cu) intermetallic catalysts. We find that the ordering degree of the M-doped PtCo catalysts increases with the decrease of melting point of M. Theoretic studies reveal that the low-melting-point metal doping can decrease the energy barrier for atom diffusion. The prepared highly ordered Ga-doped PtCo catalyst exhibits a large mass activity of 1.07 A mg
Pt
−1
at 0.9 V in H
2
-O
2
fuel cells and a rated power density of 1.05 W cm
−2
in H
2
-air fuel cells, with a Pt loading of 0.075 mg
Pt
cm
−2
.
Vascular calcification (VC) is a major risk factor for cardiovascular mortality in chronic renal failure (CRF) patients, but the pathogenesis remains partially unknown and effective therapeutic ...targets should be urgently explored. Here we pursued the therapeutic role of rapamycin in CRF-related VC. Mammalian target of rapamycin (mTOR) signal was activated in the aortic wall of CRF rats. As expected, oral rapamycin administration significantly reduced VC by inhibiting mTOR in rats with CRF. Further in vitro results showed that activation of mTOR by both pharmacological agent and genetic method promoted, while inhibition of mTOR reduced, inorganic phosphate-induced vascular smooth muscle cell (VSMC) calcification and chondrogenic/osteogenic gene expression, which were independent of autophagy and apoptosis. Interestingly, the expression of Klotho, an antiaging gene that suppresses VC, was reduced in calcified vasculature, whereas rapamycin reversed membrane and secreted Klotho decline through mTOR inhibition. When mTOR signaling was enhanced by either mTOR overexpression or deletion of tuberous sclerosis 1, Klotho mRNA was further decreased in phosphate-treated VSMCs, suggesting a vital association between mTOR signaling and Klotho expression. More importantly, rapamycin failed to reduce VC in the absence of Klotho by using either siRNA knockdown of Klotho or Klotho knockout mice. Thus, Klotho has a critical role in mediating the observed decrease in calcification by rapamycin in vitro and in vivo.
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The development of zinc-ion storage cathode materials for aqueous zinc-ion batteries (AZIBs) is a necessary step for the construction of large-scale electrochemical energy conversion ...and storage devices. Iron-doped alpha-manganese dioxide (α-MnO2) nanocomposites were achieved in this study via pre-intercalation of Fe3+ during the formation of α-MnO2 crystals. A polypyrrole (PPy) granular layer was fabricated on the surface of α-MnO2 using acid-catalyzed polymerization of pyrroles. The pre-intercalation of Fe3+ effectively enlarges the lattice spacing of α-MnO2 and consequently decreases the hindrance for Zn2+ insertion/extraction in the iron-doped α-MnO2 coated by PPy (Fe/α-MnO2@PPy) composite. Meanwhile, the PPy buffer layer can ameliorate electron and ion conductivity and prevent dissolution of α-MnO2during the charge/discharge process. This unique structure makes the Fe/α-MnO2@PPy composite an efficient zinc-ion storage cathode for AZIBs. The targeted Fe/α-MnO2@PPy cathode achieves superior performance with reversible specific capacity (270 mA h g−1 at 100 mA g−1) and exhibits highdiffusioncoefficientof 10−10–10−14 cm−2 s−1. Therefore, a feasible approach is implemented on advanced electrode materials using in AZIBs for practical applications.
The use of volatile organic compounds (VOCs) produced by microorganisms for the biological control of plant diseases has attracted much attention in recent years. In this study, the antifungal ...activity and identity of VOCs produced by
Rahnella aquatilis
JZ-GX1 isolated from the rhizosphere soil of pine were determined and analyzed. The effect of the VOCs on the mycelial growth of
Colletotrichum gloeosporioides
, the pathogen of
Liriodendron chinense
×
tulipifera
black spot, was determined by a joined-petri dish fumigation method. An
in vitro
leaf inoculation method was used to determine the fumigation effect of the VOCs on
Liriodendron
black spot. VOCs with antifungal activity were collected by headspace solid-phase microextraction (SPME), and their components were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the VOCs secreted by JZ-GX1 inhibited the mycelial growth of the tested pathogen. The VOCs destroyed the morphology of the mycelium, significantly increased the permeability of the cell membrane and downregulated the expression of pathogenicity-related genes during mycelial infection, thus inhibiting the expansion of anthracnose disease spots in leaves. In the volatile compound profile, 3-methyl-1-butanol and 2-phenylethyl methyl ether significantly inhibited the mycelial growth and spore germination of
C. gloeosporioides
. This work provides a new strategy for the research and application of microorganisms and bioactive compounds to control plant anthracnose.
Abstract Mrk 501 is a prototypical high-synchrotron-peaked blazar and serves as one of the primary targets for the Imaging X-ray Polarimetry Explorer (IXPE). In this study, we report X-ray ...polarization measurements of Mrk 501 based on six IXPE observations. The detection of X-ray polarization at a confidence level exceeding 99% is achieved in four out of the six observations conducted across the entire energy range (2–8 keV) of IXPE. The maximum polarization degree (Π X ) is measured to be 15.8% ± 2.8%, accompanied by a polarization angle ( ψ X ) of 98.°0 ± 5.°1 at a confidence level of 5.6 σ . During the remaining two observations, only an upper limit of Π X < 12% could be derived at the 99% confidence level. No temporal variability in polarization is observed throughout all six IXPE observations for Mrk 501. A discernible trend of energy-dependent variation in the polarization degree is detected in optical spectropolarimetry; however, no analogous indication is observed in Π X . The chromatic behavior of Π and the consistent values of ψ across different frequencies from X-ray to radio bands, along with the agreement between ψ and jet position angle, strongly support the interpretation of the energy-stratified model with shock-accelerated particles in the jet of Mrk 501. Additionally, the possibility of the presence of a global helical magnetic field in the jet of Mrk 501 is discussed.
Iron deficiency in soil has crucially restricted agricultural and forestry production. Volatile organic compounds (VOCs) produced by beneficial microorganisms have been proven to play an important ...role in inducing abiotic stress tolerance in plants. We investigated the effects of VOCs released by the rhizobacterium
Rahnella aquatilis
JZ-GX1 on the growth and root parameters of
Arabidopsis thaliana
under iron deficiency. The effect of the rhizobacterial VOCs on the gene expression in iron uptake and hormone signaling pathways were detected by RT-qPCR. Finally, the VOCs of the JZ-GX1 strain that could promote plant growth under iron deficiency stress were screened. The results showed that the JZ-GX1 strain could induce
A. thaliana
tolerance to iron deficiency stress by promoting the development of lateral roots and root hairs and increasing the activities of H
+
ATPase and Fe
3+
reductase. In addition, the
AHA2
,
FRO2
, and
IRT1
genes of
A. thaliana
exposed to JZ-GX1-emitted VOCs were upregulated 25-, 1. 81-, and 1.35-fold, respectively, and expression of the abscisic acid (ABA) synthesis gene
NCED3
was upregulated on both the 3rd and 5th days. Organic compounds were analyzed in the headspace of JZ-GX1 cultures, 2-undecanone and 3-methyl-1-butanol were found to promote
Medicago sativa
and
A. thaliana
growth under iron-limited conditions. These results demonstrated that the VOCs of
R. aquatilis
JZ-GX1 have good potential in promoting iron absorption in plants.
In May 2019, Aucuba japonica var. variegata, known as an evergreen shrub, was found to have multiple leaf spots in Nanjing City, Jiangsu Province, China. A fungus was isolated from the margins of the ...lesions and one isolate JS‐RL3 was selected for identification and pathogenicity tests. The morphological characteristics of the fungus were similar to Botrytis cinerea. Phylogenetic analysis using concatenated sequences of ITS and G3PDH also showed that isolate JS‐RL3 clustered with strains of B. cinerea, a relationship supported by a 100% bootstrap value. This report is the first of B. cinerea causing leaf spots on A. japonica var. variegata.
Iron deficiency causes chlorosis and growth inhibition in Cinnamomum camphora, an important landscaping tree species. Siderophores produced by plant growth-promoting rhizobacteria have been widely ...reported to play an indispensable role in plant iron nutrition. However, little to date has been determined about how microbial siderophores promote plant iron absorption. In this study, multidisciplinary approaches, including physiological, biochemical and transcriptome methods, were used to investigate the role of deferoxamine (DFO) in regulating Fe availability in C. camphora seedlings. Our results showed that DFO supplementation significantly increased the Fe2+ content, SPAD value and ferric-chelate reductase (FCR) activity in plants, suggesting its beneficial effect under Fe deficiency. This DFO-driven amelioration of Fe deficiency was further supported by the improvement of photosynthesis. Intriguingly, DFO treatment activated the metabolic pathway of glutathione (GSH) synthesis, and exogenous spraying reduced glutathione and also alleviated chlorosis in C. camphora. In addition, the expression of some Fe acquisition and transport-related genes, including CcbHLH, CcFRO6, CcIRT2, CcNramp5, CcOPT3 and CcVIT4, was significantly upregulated by DFO treatment. Collectively, our data demonstrated an effective, economical and feasible organic iron-complexing agent for iron-deficient camphor trees and provided new insights into the mechanism by which siderophores promote iron absorption in plants.
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