To conquer the bottleneck of sluggish kinetics in cathodic oxygen reduction reaction (ORR) of metal‐air batteries, catalysts with dual‐active centers have stood out. Here, a “pre‐division metal ...clusters” strategy is firstly conceived to fabricate a N,S‐dual doped honeycomb‐like carbon matrix inlaid with CoN4 sites and wrapped Co2P nanoclusters as dual‐active centers (Co2P/CoN4@NSC‐500). A crystalline {CoII2} coordination cluster divided by periphery second organic layers is well‐designed to realize delocalized dispersion before calcination. The optimal Co2P/CoN4@NSC‐500 executes excellent 4e− ORR activity surpassing the benchmark Pt/C. Theoretical calculation results reveal that the CoN4 sites and Co2P nanoclusters can synergistically quicken the formation of *OOH on Co sites. The rechargeable Zn‐air battery (ZAB) assembled by Co2P/CoN4@NSC‐500 delivers ultralong cycling stability over 1742 hours (3484 cycles) under 5 mA cm−2 and can light up a 2.4 V LED bulb for ≈264 hours, evidencing the promising practical application potentials in portable devices.
A “pre‐division metal clusters” strategy is first conceived to fabricate dual‐active center catalysts (Co2P/CoN4@NSC‐500) with dispersed CoN4 and Co2P sites. The optimal catalyst executes superior ORR activity and was applied in ultralong Zn‐air batteries surpassing the benchmark 20 % Pt/C. Theoretical calculations demonstrate that the dual‐active sites synergistically quicken the formation of the *OOH intermediate, greatly boosting the performance.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
High-performance fluorescence sensors combining convenience, low cost and high sensitivity are prospective for water pollution and human health. Luminescent metal-organic frameworks (LMOFs) as ...sensors can meet these criteria for high efficient detection of toxic metal ions. Herein, a new LMOF LCU-109 has been fabricated by Sharpless
in situ
tetrazole synthesis system assisted by polycarboxylic O-donor ligand. It showed a 2D binodal (3,6)-connected
kgd
structure with multiple N and O dual-functional sites for detecting guest metal ions. As expected,
LCU-109
can be highly sensitive and selectively detect trace amounts of Fe
3+
and Cu
2+
ions in an aqueous solution by the luminescence quenching mechanism. Notably, the detection limits (LODs) of Fe
3+
and Cu
2+
ions are 0.0043 and 0.0028 ppm, respectively, in water, which are significantly lower than the minimum standards stipulated for drinking water by the World Health Organization (WHO) (0.3/2.0 ppm) and U.S. Environmental Protection Agency (USEPA) (0.3/1.2 ppm). Moreover,
LCU-109
also shows excellent luminescent sensing activities for Fe
3+
and Cu
2+
ions in simulated HEPES biological system and actual river water with low LODs of 0.034/0.019 ppm and 0.0756/0.107 ppm, respectively, which is also lower than the standard of WHO and USEPA. Moreover, convenient and real-time naked eye detection effects are provided by the exquisitely made
LCU-109
fluorescent test papers. Importantly, combining density functional theory (DFT) calculations with a variety of experiments, the fluorescence quenching mechanism for energy competitive absorption and weak interaction is further revealed.
A 2D MOF displays high performance luminescence quenching for detecting Fe
3+
and Cu
2+
in pure water, actual river water and simulated HEPES with superior low LODs. Multiple experiments and DFT calculations co-verify a weak interaction quenching mechanism.
Mitochondria are the double membrane organelles providing most of the energy for cells. In addition, mitochondria also play essential roles in various cellular biological processes such as calcium ...signaling, apoptosis, ROS generation, cell growth, and cell cycle. Mitochondrial dysfunction is observed in various neurological disorders which harbor acute and chronic neural injury such as neurodegenerative diseases and ischemia, hypoxia-induced brain injury. In this review, we describe how mitochondrial dysfunction contributes to the pathogenesis of neurological disorders which manifest chronic or acute neural injury.
Flonicamid (N-cyanomethyl-4-trifluoromethylnicotinamide, FLO) is a new type of pyridinecarboxamide insecticide that exhibits particularly good efficacy in pest control. However, the extensive use of ...FLO in agricultural production poses environmental risks. Hence, its environmental behavior and degradation mechanism have received increasing attention. Microvirga flocculans CGMCC 1.16731 rapidly degrades FLO to produce the intermediate N-(4-trifluoromethylnicotinoyl) glycinamide (TFNG-AM) and the end acid metabolite 4-(trifluoromethyl) nicotinol glycine (TFNG). This bioconversion is mediated by the nitrile hydratase/amidase system; however, the amidase that is responsible for the conversion of TFNG-AM to TFNG has not yet been reported. Here, gene cloning, overexpression in Escherichia coli and characterization of pure enzymes showed that two amidases—AmiA and AmiB—hydrolyzed TFNG-AM to TFNG. AmiA and AmiB showed only 20–30% identity to experimentally characterized amidase signature family members, and represent novel amidases. Compared with AmiA, AmiB was more sensitive to silver and copper ions but more resistant to organic solvents. Both enzymes demonstrated good pH tolerance and exhibited broad amide substrate specificity. Homology modeling suggested that residues Asp191 and Ser195 may strongly affect the catalytic activity of AmiA and AmiB, respectively. The present study furthers our understanding of the enzymatic mechanisms of biodegradation of nitrile-containing insecticides and may aid in the development of a bioremediation agent for FLO.
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•This is the first report on amidases involved in microbial metabolism of FLO.•M. flocculans efficiently degrades insecticide FLO via the NHase/amidase pathway.•AmiA and AmiB show less than 30% identities to other reported characterized amidases.•AmiA and AmiB exhibited good thermal stability and broad substrate specificity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Alzheimer's disease (AD) is a neurodegenerative disorder with cognitive impairment and abnormal mental behaviour. There is currently no effective cure. The development of early diagnostic markers and ...the mining of potential therapeutic targets are one of the important strategies. This study aimed to explore potential biomarkers or therapeutic targets related to AD in the hippocampus and prefrontal cortex, two brain regions highly related to AD. Differentially expressed genes and miRNAs between AD patients and healthy controls were obtained from the Gene Expression Omnibus database. The mRNA‐miRNA network was constructed and key genes involved in AD were screened out by protein–protein interaction analysis, and were subsequently verified by independent datasets and qPCR in an AD mouse model. Our findings showed that six hub genes including CALN1, TRPM7, ATR, SOCS3, MOB3A and OGDH were believed to be involved in the pathogenesis of AD. Western blot analysis further determined that CALN1, ATR and OGDH were the possible biomarkers and therapeutic targets for AD. In addition, 6 possible miRNAs biomarkers have also been verified by qPCR on AD animal models. Our findings may benefit clinical diagnosis and early prevention of AD.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
High-performance lithium ion batteries (LIBs) juggling high reversible capacity, excellent rate capability and ultralong cycle stability are urgently needed for all electronic devices. Here we report ...employing a vesicle-like porous N-doped carbon material (abbr. N/C-900) as a highly active anode for LIBs to balance high capacity, high rate and long life. The N/C-900 material was fabricated by pyrolysis of a designed crystal MOF
LCU-104
, which exhibits a graceful two-fold interpenetrating structural feature of N-rich nanocages {Zn
6
(dttz)
4
} linked through an N-donor ligand bpp (H
3
dttz = 4,5-di(1
H
-tetrazol-5-yl)-2
H
-1,2,3-triazole, bpp = 1,3-bis(4-pyridyl)propane). The features of
LCU-104
combine high N content (35.1%), interpenetration, and explosive characteristics, which endow the derived N/C material with optimized N-doping for tuning its chemical and electronic structure, a suitably thicker wall to enhance its stability, and a vesicle-like structure to improve its porosity. As an anode material for LIBs, N/C-900 delivers a highly reversible capacity of
ca.
734 mA h g
−1
at a large current density of 1 A g
−1
until the 2000th cycle, revealing its ultralong cycle stability and excellent rate capability. The unique structure and preferential interaction between abundant pyridinic N active sites and Li atoms are responsible for the improved excellent lithium storage capacity and durability performances of the anode according to analysis of the results of computational modeling.
MOF-derived vesicle-like N-doped carbon presents high reversible capacity, high rate capability and ultralong cycle life as LIB anode. Theoretical calculation verifies the experimental results.
Flonicamid (N-cyanomethyl-4-trifluoromethylnicotinamide, FLO) is a new type of pyridinamide insecticide that regulates insect growth. Because of its wide application in agricultural production and ...high solubility in water, it poses potential risks to aquatic environments and food chain. In the present study, Ensifer adhaerens CGMCC 6315 was shown to efficiently transform FLO into N-(4-trifluoromethylnicotinoyl) glycinamide (TFNG-AM) via a hydration pathway mediated by two nitrile hydratases, PnhA and CnhA. In pure culture, resting cells of E. adhaerens CGMCC 6315 degraded 92% of 0.87 mmol/L FLO within 24 h at 30 degreesC (half-life 7.4 h). Both free and immobilized (by gel beads, using calcium alginate as a carrier) E. adhaerens CGMCC 6315 cells effectively degraded FLO in surface water. PnhA has, to our knowledge, the highest reported degradation activity toward FLO, V.sub.max = 88.7 U/mg (K.sub.m = 2.96 mmol/L). Addition of copper ions could increase the enzyme activity of CnhA toward FLO by 4.2-fold. Structural homology modeling indicated that residue beta-Glu56 may be important for the observed significant difference in enzyme activity between PnhA and CnhA. Application of E. adhaerens may be a good strategy for bioremediation of FLO in surface water. This work furthers our understanding of the enzymatic mechanisms of biodegradation of nitrile-containing insecticides and provides effective transformation strategies for microbial remediation of FLO contamination.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory impairments, which has no effective therapy. Stem cell transplantation shows great potential in the therapy of various ...disease. However, the application of stem cell therapy in neurological disorders, especially the ones with a long-term disease course such as AD, is limited by the delivery approach due to the presence of the brain blood barrier. So far, the most commonly used delivery approach in the therapy of neurological disorders with stem cells in preclinical and clinical studies are intracranial injection and intrathecal injection, both of which are invasive. In the present study, we use repetitive intranasal delivery of human neural stem cells (hNSCs) to the brains of APP/PS1 transgenic mice to investigate the effect of hNSCs on the pathology of AD. The results indicate that the intranasally transplanted hNSCs survive and exhibit extensive migration and higher neuronal differentiation, with a relatively limited glial differentiation. A proportion of intranasally transplanted hNSCs differentiate to cholinergic neurons, which rescue cholinergic dysfunction in APP/PS1 mice. In addition, intranasal transplantation of hNSCs attenuates β-amyloid accumulation by upregulating the expression of β-amyloid degrading enzymes, insulin-degrading enzymes, and neprilysin. Moreover, intranasal transplantation of hNSCs ameliorates other AD-like pathology including neuroinflammation, cholinergic dysfunction, and pericytic and synaptic loss, while enhancing adult hippocampal neurogenesis, eventually rescuing the cognitive deficits of APP/PS1 transgenic mice. Thus, our findings highlight that intranasal transplantation of hNSCs benefits cognition through multiple mechanisms, and exhibit the great potential of intranasal administration of stem cells as a non-invasive therapeutic strategy for AD.
is a metabolically diverse genus of plant growth-promoting rhizobacteria (PGPR) that engages in mutually beneficial interactions between plants and microbes. Unlike most PGPR,
cannot synthesize the ...phytohormone indole-3-acetic acid (IAA) via tryptophan. However, we found that
strain CGMCC 4969 can produce IAA using indole-3-acetonitrile (IAN) as the precursor. Thus, in the present study, the IAA synthesis mechanism of
CGMCC 4969 was investigated.
CGMCC 4969 metabolized IAN to IAA through both a nitrilase-dependent pathway and a nitrile hydratase (NHase) and amidase-dependent pathway. Cobalt enhanced the metabolic flux via the NHase/amidase, by which IAN was rapidly converted to indole-3-acetamide (IAM) and in turn to IAA. IAN stimulated metabolic flux via the nitrilase, by which IAN was rapidly converted to IAA. Subsequently, the IAA was degraded.
CGMCC 4969 can use IAN as the sole carbon and nitrogen source for growth. Genome sequencing confirmed the IAA synthesis pathways. Gene cloning and overexpression in
indicated that NitA has nitrilase activity and IamA has amidase activity to respectively transform IAN and IAM to IAA. Interestingly, NitA showed a close genetic relationship with the nitrilase of the phytopathogen
Quantitative PCR analysis indicated that the NHase/amidase system is constitutively expressed, whereas the nitrilase is inducible. The present study helps our understanding of the versatile functions of
nitrile-converting enzymes that mediate IAA synthesis and the interactions between plants and these bacteria.
We demonstrated that
CGMCC 4969 has two enzymatic systems-nitrilase and nitrile hydratase/amidase-that convert indole-3-acetonitrile (IAN) to the important plant hormone indole-3-acetic acid (IAA). The two IAA synthesis systems have very different regulatory mechanisms, affecting the IAA synthesis rate and duration. The nitrilase was induced by IAN, which was rapidly converted to IAA; subsequently, IAA was rapidly consumed for cell growth. The nitrile hydratase (NHase) and amidase system was constitutively expressed and slowly but continuously synthesized IAA. In addition to synthesizing IAA from IAN, CGMCC 4969 has a rapid IAA degradation system, which would be helpful for a host plant to eliminate redundant IAA. This study indicates that the plant growth-promoting rhizobacterium
CGMCC 4969 has the potential to be used by host plants to regulate the IAA level.
The insecticide imidacloprid (IMI), which is used worldwide, pollutes environments and has significant ecotoxicological effects. Microbial metabolism and photolysis are the major pathways of IMI ...degradation in natural environments. Several studies have reported that the metabolites of IMI nitroreduction are more toxic to some insects and mammals than IMI itself. Thus, environmental degradation of IMI may enhance the ecotoxicity of IMI and have adverse effects on non-target organisms. Here, we report that an actinomycete—Gordonia alkanivorans CGMCC 21704—transforms IMI to a nitroreduction metabolite, nitroso IMI. Resting cells of G. alkanivorans at OD600 nm = 10 transformed 95.7% of 200 mg L−1 IMI to nitroso IMI in 4 d. Nitroso IMI was stable at pH 4–9. However, it rapidly degraded under sunlight via multiple oxidation, dehalogenation, and oxidative cleavage reactions to form 10 derivatives; the half-life of nitroso IMI in photolysis was 0.41 h, compared with 6.19 h for IMI. Acute toxicity studies showed that the half maximal effective concentration (EC50) values of IMI, nitroso IMI, and its photolytic metabolites toward the planktonic crustacean Daphnia magna for immobilization (exposed to the test compounds for 48 h) were 17.70, 9.38, 8.44 mg L−1, respectively. The half-life of nitroso IMI in various soils was also examined. The present study reveals that microbial nitroreduction accelerates IMI degradation and the nitroso IMI is easily decomposed by sunlight and in soil. However, nitroso IMI and its photolytic products have higher toxicity toward D. magna than the parent compound IMI, and therefore increase the ecotoxicity of IMI.
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•A new isolate Gordonia alkanivorans effectively transformed IMI to nitroso derivate.•The genome of G. alkanivorans CGMCC 21704 has been determined.•The nitroso IMI is easily degraded by photolysis and in soils.•10 derivates were produced under photolysis by sunlight.•Nitroso IMI and its photolytic products were more toxic to D. magna than IMI.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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