744 research outputs found
Mass Spectrometric Study of Acoustically Levitated Droplet Illuminates Molecular-Level Mechanism of Photodynamic Therapy for Cancer involving Lipid Oxidation
Even though the general mechanism of photodynamic cancer therapy is known, the details and consequences of the reactions between the photosensitizer‐generated singlet oxygen and substrate molecules remain elusive at the molecular level. Using temoporfin as the photosensitizer, here we combine field‐induced droplet ionization mass spectrometry and acoustic levitation techniques to study the “wall‐less” oxidation reactions of 18:1 cardiolipin and 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phospho‐(1′‐rac‐glycerol) (POPG) mediated by singlet oxygen at the air–water interface of levitated water droplets. For both cardiolipin and POPG, every unsaturated oleyl chain is oxidized to an allyl hydroperoxide, which surprisingly is immune to further oxidation. This is attributed to the increased hydrophilicity of the oxidized chain, which attracts it toward the water phase, thereby increasing membrane permeability and eventually triggering cell death
Quaternary Hydrides Pd1-y-zAgyCuzHx Embedded Atom Method Potentials for Hydrogen Energy Applications
The Pd-H system has attracted extensive attention. Pd can absorb considerable H at room temperature, this ability is reversible, so it is suitable for multiple energy applications. Pd-Ag alloys possess higher H permeability, solubility and narrower miscibility gap with better mechanical properties than pure Pd, but sulfur poisoning remains an issue. Pd-Cu alloys have excellent resistance to sulfur and carbon monoxide poisoning and hydrogen embrittlement, good mechanical properties, and broader temperature working environments over pure Pd, but relatively lower hydrogen permeability and solubility than pure Pd and Pd-Ag alloys. This suggests that alloying Pd with Ag and Cu to create Pd-Ag-Cu ternary alloys can optimize the overall performance and substantially lowers the cost. Thus, in this research, the first embedded atom method potentials for the quaternary hydrides Pd1-y-zAgyCuzHx were provided. The fully analytical potentials are fitted utilizing the central atom method without performing time-consuming molecular dynamics simulations
Species-specific effects of microplastics on juvenile fishes
Microplastics contamination have been extensively reported in aquatic ecosystem and organisms. It is wildly acknowledged that the ingestion, accumulation and elimination of microplastics in fishes are species-specific, which mainly depending on the feeding behavior. This study aimed to investigate the effects of microplastics on the morphology and inflammatory response in intestines of fishes with different feeding types. Largemouth bass (carnivorous fish), grass carp (herbivorous fish) and Jian carp (omnivorous fish) were used as organism model. The contributing concentration and size of microplastics were explored as well as the response time and legacy effect in fishes. Two different sizes of polystyrene microplastics (80 nm and 8 μm) were set at three concentrations. And samples were analyzed at different exposure times and depuration times. Histological analysis indicated that multiple abnormalities in intestines were presented in three species fishes after acute exposure microplastics. The mRNA abundance of immune-related genes in the intestine tissues of fishes were significantly fluctuant. There were differential expressions of genes coping with differential sizes and concentrations of microplastics exposure in different fishes. The reason for the difference effects of microplastics on fishes was still unclear but could be due to the difference in the structure and function of the digestive system. These results provided a theoretical basis to further analysis of the mechanism of fish intestinal pathology caused by microplastics
The interaction between miR160 and miR165/166 in the control of leaf development and drought tolerance in Arabidopsis
MicroRNAs (miRNAs) are a class of non-coding RNAs that play important roles in plant development and abiotic stresses. To date, studies have mainly focused on the roles of individual miRNAs, however, a few have addressed the interactions among multiple miRNAs. In this study, we investigated the interplay and regulatory circuit between miR160 and miR165/166 and its effect on leaf development and drought tolerance in Arabidopsis using Short Tandem Target Mimic (STTM). By crossing STTM160 Arabidopsis with STTM165/166, we successfully generated a double mutant of miR160 and miR165/166. The double mutant plants exhibited a series of compromised phenotypes in leaf development and drought tolerance in comparison to phenotypic alterations in the single STTM lines. RNA-seq and qRT-PCR analyses suggested that the expression levels of auxin and ABA signaling genes in the STTM-directed double mutant were compromised compared to the two single mutants. Our results also suggested that miR160-directed regulation of auxin response factors (ARFs) contribute to leaf development via auxin signaling genes, whereas miR165/166- mediated HD-ZIP IIIs regulation confers drought tolerance through ABA signaling. Our studies further indicated that ARFs and HD-ZIP IIIs may play opposite roles in the regulation of leaf development and drought tolerance that can be further applied to other crops for agronomic traits improvement
The interaction between miR160 and miR165/166 in the control of leaf development and drought tolerance in Arabidopsis
MicroRNAs (miRNAs) are a class of non-coding RNAs that play important roles in plant development and abiotic stresses. To date, studies have mainly focused on the roles of individual miRNAs, however, a few have addressed the interactions among multiple miRNAs. In this study, we investigated the interplay and regulatory circuit between miR160 and miR165/166 and its effect on leaf development and drought tolerance in Arabidopsis using Short Tandem Target Mimic (STTM). By crossing STTM160 Arabidopsis with STTM165/166, we successfully generated a double mutant of miR160 and miR165/166. The double mutant plants exhibited a series of compromised phenotypes in leaf development and drought tolerance in comparison to phenotypic alterations in the single STTM lines. RNA-seq and qRT-PCR analyses suggested that the expression levels of auxin and ABA signaling genes in the STTM-directed double mutant were compromised compared to the two single mutants. Our results also suggested that miR160-directed regulation of auxin response factors (ARFs) contribute to leaf development via auxin signaling genes, whereas miR165/166- mediated HD-ZIP IIIs regulation confers drought tolerance through ABA signaling. Our studies further indicated that ARFs and HD-ZIP IIIs may play opposite roles in the regulation of leaf development and drought tolerance that can be further applied to other crops for agronomic traits improvement
Portable wireless electrocorticography system with a fexible microelectrodes array for epilepsy treatment
In this paper, we present a portable wireless electrocorticography (ECoG) system. It uses a high
resolution 32-channel fexible ECoG electrodes array to collect electrical signals of brain activities and to
stimulate the lesions. Electronic circuits are designed for signal acquisition, processing and transmission
using Bluetooth Low Energy 4 (LTE4) for wireless communication with cell phone. In-vivo experiments
on a rat show that the fexible ECoG system can accurately record electrical signals of brain activities
and transmit them to cell phone with a maximal sampling rate of 30 ksampling/s per channel. It
demonstrates that the epilepsy lesions can be detected, located and treated through the ECoG system.
The wireless ECoG system has low energy consumption and high brain spatial resolution, thus has great
prospects for future application
Effects of the stress hormone norepinephrine on the probiotic properties of Levilactobacillus: antibacterial colonization, anti-inflammation, and antioxidation
Probiotics as antibiotic alternatives are unstable for use under stress in clinical applications. To explore the influence of catecholamine hormones on probiotic bacterial inhibition and antimicrobial activity, we tested the effects of norepinephrine (NE) on Levilactobacillus in vitro and in a mouse model. The in vitro results showed that in the presence of NE, 80% of Levilactobacillus strains showed increased growth rate and more than 80% of the strains indicated lower antimicrobial activity at 22 h. Furthermore, in the mouse model, NE weakens the protective effect of L. brevis 23,017 on Escherichia coli infection, which is shown by the decreased ability of antibacterial colonization, antioxidation, and anti-inflammation, and downregulating the expression of antioxidant genes and intestinal mucosal barrier-related genes. At the same time, the addition of NE modulates the bacterial microbiota richness and diversity in the intestine, disrupting the balance of intestinal probiotics. These findings provide evidence that NE reduces the probiotic ability of Levilactobacillus and illustrates the plasticity of the probiotics in response to the intestinal microenvironment under stress
Boron-Made N2: Realization of a B≡B Triple Bond in the B2Al3− Cluster
Until now, all B≡B triple bonds have been achieved by adopting two ligands in the L→B≡B←L manner. Herein, we report an alternative route of designing the B≡B bonds based on the assumption that by acquiring two extra electrons, an element with the atomic number Z can have properties similar to those of the element with the atomic number Z+2. Specifically, we show that due to the electron donation from Al to B, the negatively charged B≡B kernel in the B2Al3− cluster mimics a triple N≡N bond. Comprehensive computational searches reveal that the global minimum structure of B2Al3− exhibits a direct B–B distance of 1.553 Å, and its calculated electron vertical detachment energies are in excellent agreement with the corresponding values of the experimental photoelectron spectrum. Chemical bonding analysis revealed one σ and two π bonds between the two B atoms, thus confirming a classical textbook B≡B triple bond, similar to that of N2
Mechanistic understanding of \u3ci\u3eN\u3c/i\u3e-glycosylation in Ebola virus glycoprotein maturation and function
The Ebola virus (EBOV) trimeric envelope glycoprotein (GP) precursors are cleaved into the receptor-binding GP1 and the fusion-mediating GP2 subunits and incorporated into virions to initiate infection. GP1 and GP2 form heterodimers that have 15 or two N-glycosylation sites (NGSs), respectively. Here we investigated the mechanism of how N-glycosylation contributes to GP expression, maturation, and function. As reported before, we found that, although GP1 NGSs are not critical, the two GP2 NGSs, Asn563 and Asn618, are essential for GP function. Further analysis uncovered that Asn563 and Asn618 regulate GP processing, demannosylation, oligomerization, and conformation. Consequently, these two NGSs are required for GP incorporation into EBOV-like particles and HIV type 1 (HIV-1) pseudovirions and determine viral transduction efficiency. Using CRISPR/Cas9 technology, we knocked out the two classical endoplasmic reticulum chaperones calnexin (CNX) and/or calreticulin (CRT) and found that bothCNXand CRT increase GP expression. Nevertheless, NGSs are not required for the GP interaction with CNX or CRT. Together, we conclude that, although Asn563 and Asn618 are not required for EBOV GP expression, they synergistically regulate its maturation, which determines its functionality
Total Glucosides of Paeony Capsule Plus Compound Glycyrrhizin Tablets for the Treatment of Severe Alopecia Areata in Children: A Randomized Controlled Trial
Total glucosides of paeony capsule (TGPC) and compound glycyrrhizin tablets (CGT) are plant extracts of glycosides. We conducted this study to examine the efficacy and safety of TGPC plus CGT for severe alopecia areata in children. 117 subjects were randomly allocated into TGPC plus CGT group or CGT group. For consecutive 12 months, subjects were given oral TGPC and CGT or oral CGT alone. The outcome measures included score of alopecia areata severity, effective rate, and adverse events observed in the 3rd, 6th, and 12th month. We found that the scores of alopecia areata severity of both groups were significantly reduced, and the scores of treatment group were lower than those of control group; for effective rate, there was no statistical difference between the two groups in the 3rd month, while in the 6th and 12th months the treatment group was superior compared with control group; the incidence rate of adverse events between the two groups was not statistically different, and no severe adverse events were observed. In conclusion, TGPC plus CGT appears effective and safe for severe alopecia areata in children.</jats:p
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