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1.
J Am Chem Soc ; 146(22): 15176-15185, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38770641

RESUMO

Stepwise oxidative addition of copper(I) complexes to form copper(III) species via single electron transfer (SET) events has been widely proposed in copper catalysis. However, direct observation and detailed investigation of these fundamental steps remain elusive owing largely to the typically slow oxidative addition rate of copper(I) complexes and the instability of the copper(III) species. We report herein a novel aryl-radical-enabled stepwise oxidative addition pathway that allows for the formation of well-defined alkyl-CuIII species from CuI complexes. The process is enabled by the SET from a CuI species to an aryl diazonium salt to form a CuII species and an aryl radical. Subsequent iodine abstraction from an alkyl iodide by the aryl radical affords an alkyl radical, which then reacts with the CuII species to form the alkyl-CuIII complex. The structure of resultant [(bpy)CuIII(CF3)2(alkyl)] complexes has been characterized by NMR spectroscopy and X-ray crystallography. Competition experiments have revealed that the rate at which different alkyl iodides undergo oxidative addition is consistent with the rate of iodine abstraction by carbon-centered radicals. The CuII intermediate formed during the SET process has been identified as a four-coordinate complex, [CuII(CH3CN)2(CF3)2], through electronic paramagnetic resonance (EPR) studies. The catalytic relevance of the high-valent organo-CuIII has been demonstrated by the C-C bond-forming reductive elimination reactivity. Finally, localized orbital bonding analysis of these formal CuIII complexes indicates inverted ligand fields in σ(Cu-CH2) bonds. These results demonstrate the stepwise oxidative addition in copper catalysis and provide a general strategy to investigate the elusive formal CuIII complexes.

2.
Opt Express ; 32(1): 969-986, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38175117

RESUMO

We study the nonreciprocal excitation and entanglement dynamics of two giant atoms (GAs) coupling to a one-dimensional waveguide. With different positions of coupling points, three configurations of two separate GAs, two braided GAs, and two nested GAs are analyzed, respectively. The coupling strengths between different coupling points are considered as complex numbers with phases. For each coupling configuration, the nonreciprocal excitation dynamics and entanglement properties, which results from the phase differences of coupling strength and the phase induced by photon propagation between the two coupling points, are studied both in Markovian and non-Markovian regimes. The analytical solutions for nonreciprocal entanglement degree are given in the Markovian regime. It shows that the steady entanglement can be reached and strongly depends on the phases. Different from the case of the Markovian regime, the entanglement degree shows oscillating behavior in the non-Markovian regime. This work may find applications in the generation and controlling of entanglement in quantum networks based on waveguide quantum electrodynamics.

3.
Chemistry ; 30(11): e202303523, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-37997021

RESUMO

A new series of biaryls, bi-linear-terphenylenes (BLTPs), were prepared using the tert-butyllithium-mediated cyclization as the key synthetic step. The three-dimensional structures of the studied compounds were verified using X-ray crystallography and DFT calculations. Tetraaryl(ethynyl)-substituted BLTPs are highly crowded molecules, and the internal rotation around the central C-C bond is restricted due to a high barrier (>50 kcal/mol). These structures contain several aryl/terphenylenyl/aryl sandwiches, where the through-space π-π (TSPP) interactions are strongly reflected in the shielding of 1 H NMR chemical shifts, reduction of oxidation potentials, increasing aromaticity of the central six-membered ring and decreasing antiaromaticity of the four-membered rings in a terphenylenyl moiety based on NICS(0) and iso-chemical shielding surfaces. Despite the restricted C-C bond associated intramolecular TSPP interactions for BLTPs in the ground state, to our surprise, the electronic coupling between two linear terphenylenes (LTPs) in BLTPs in the excited state is weak, so that the excited-state behavior is dominated by the corresponding monomeric LTPs. In other words, all BLTPs undergo ultrafast relaxation dynamics via strong exciton-vibration coupling, acting as a blue-light absorber with essentially no emission.

4.
FASEB J ; 37(6): e22965, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37171272

RESUMO

Chronic alcohol consumption is a major risk factor for alcoholic steatohepatitis (ASH). Previous studies have shown that direct injury of hepatocytes is the key factor in its occurrence and development. However, our study shows that the role of Kupffer cells in ASH cannot be ignored. We isolated Kupffer cells from the livers of ASH mice and found that alcohol consumption induced Kupffer cell pyroptosis and increased the release of interleukin-1ß (IL-1ß). Furthermore, we screened the related m6A enzyme methyltransferase-like 3 (METTL3) from liver Kupffer cells, and found that silencing METTL3 alleviated inflammatory cytokine eruption by Kupffer cell pyroptosis in ASH mice. In vitro, we silenced METTL3 with lentivirus in BMDMs and RAW264.7 cells and confirmed that METTL3 could reduce pyroptosis by influencing the splicing of pri-miR-34A. Together, our results revealed a critical role of KC pyroptosis in ASH and highlighted the mechanism by which METLL3 relieves cell pyroptosis, which could be a promising therapeutic strategy for ASH.


Assuntos
Fígado Gorduroso Alcoólico , MicroRNAs , Animais , Camundongos , Células de Kupffer , Piroptose , Hepatócitos , Metiltransferases
5.
Artigo em Inglês | MEDLINE | ID: mdl-38194256

RESUMO

Two novel halophilic archaeal strains (XZGYJ-43T and ZJ1T) were isolated from Mangkang ancient solar saltern (Tibet, PR China) and Zhujiang river inlet (Guangdong, PR China), respectively. The comparison of the 16S rRNA gene sequences revealed that strain XZGYJ-43T is related to the current species of the family Halobacteriaceae (89.2-91.7% similarity) and strain ZJ1T showed 94.7-98.3% similarity to the current species of the genus Haladaptatus. Phylogenetic analyses based on 16S rRNA genes, rpoB' genes and genomes indicated that strain XZGYJ-43T is separate from the related genera, Halocalculus, Salarchaeum and Halarchaeum of the family Halobacteriaceae, and strain ZJ1T tightly clusters with the current species of the genus Haladaptatus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between strain XZGYJ-43T and the current species of the family Halobacteriaceae were 71-75, 20-25 and 59-68 %, and these values between strain ZJ1T and the current species of the genus Haladaptatus were 77-81, 27-32 and 76-82 %, respectively, clearly below the thresholds for prokaryotic species demarcation. These two strains could be distinguished from their relatives according to differential phenotypic characteristics. The major polar lipids of strain XZGYJ-43T were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), mannosyl glucosyl diether (DGD-1; DGD-PA) and sulphated mannosyl glucosyl diether (S-DGD-1; S-DGD-PA), and those of strain ZJ1T were PA, PG, PGP-Me, DGD-PA, S-DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. Based on phenotypic, phylogenetic and genomic data, strain XZGYJ-43T (=CGMCC 1.13890T=JCM 33735T) represents a novel species of a new genus within the family Halobacteriaceae, and strain ZJ1T (=CGMCC 1.18785T=JCM 34917T) represents a novel species of the genus Haladaptatus, for which the names Halospeciosus flavus gen. nov., sp. nov. and Haladaptatus caseinilyticus sp. nov. are proposed, respectively.


Assuntos
Halobacteriaceae , Halobacteriales , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Ácidos Graxos/química , Halobacteriaceae/genética , Fosfatidilgliceróis
6.
Artigo em Inglês | MEDLINE | ID: mdl-38197785

RESUMO

Two extremely halophilic archaeal strains, GSLN9T and XZYJT29T, were isolated from the saline soil in different regions of western China. Both strains GSLN9T and XZYJT29T have two 16S rRNA genes with similarities of 95.1 and 94.8 %, respectively. Strain GSLN9T was mostly related to the genus Halomicrococcus based on 16S rRNA (showing 91.0-96.0 % identities) and rpoB' genes (showing 92.0 % identity). Strain XZYJT29T showed 92.1-97.6 % (16S rRNA gene) and 91.4-93.1 % (rpoB' gene) sequence similarities to its relatives in the genus Halosimplex, respectively. The polar lipid profile of strain GSLN9T included phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate (PGS), sulphated mannosyl glucosyl diether (S-DGD-1) and sulphated galactosyl mannosyl glucosyl diether (S-TGD-1), mostly similar to that of Halomicrococcus hydrotolerans H22T. PA, PG, PGP-Me, S-DGD-1 (S-DGD-PA), S2-DGD, S-TGD-1 and an unidentified glycolipid were detected in strain XZYJT29T; this polar lipid composition is similar to those of members of the genus Halosimplex. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between these two strains and their relatives of the genera Halomicrococcus and Halosimplex were no more than 82, 27 and 80 %, respectively, much lower than the thresholds for species demarcation. Other phenotypic characterization results indicated that strains GSLN9T and XZYJT29T can be differentiated from the current species of the genera Halomicrococcus and Halosimplex, respectively. These results revealed that strains GSLN9T (=CGMCC 1.15215T=JCM 30842T) and XZYJT29T (=CGMCC 1.15828T=JCM 31853T) represent novel species of Halomicrococcus and Halosimplex, for which the names Halomicrococcus gelatinilyticus sp. nov. and Halosimplex aquaticum sp. nov. are proposed.


Assuntos
Halobacteriaceae , Halobacteriales , RNA Ribossômico 16S/genética , Filogenia , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Ácidos Graxos/química , Halobacteriaceae/genética , Fosfatidilgliceróis , Solo , Sulfatos
7.
Extremophiles ; 28(1): 10, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38214762

RESUMO

The genera Haloarcula and Halomicroarcula are the most closely related genera within the family Haloarculaceae (class Halobacteria). The respective 16S rRNA genes of type strains from the genus Haloarcula showed 94.7-96.5% similarities to their homologous genes of type strains from the genus Halomicroarcula. The Haloarcula species showed 89.3-92.8% rpoB' gene similarities to Halomicroarcula species. These similarities were higher than the proposed genus boundary. Phylogenomic analysis revealed that these two genera formed a tight cluster separated from Halomicrobium with high bootstrap confidence. The average amino acid identity (AAI) values among Haloarcula and Halomicroarcula were 70.1-74.5%, higher than the cutoff value (67.0%) to differentiate the genera Haloarcula and Halomicroarcula from Halomicrobium. These results indicated that the genus Halomicroarcula should be merged with Haloarcula. Then, six novel species are described based on strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T isolated from coarse sea salt, marine solar saltern, and salt lake (China). These six strains formed separate clades (90.1-99.3% 16S rRNA and 89.0-94.9% rpoB' gene similarities) and then clustered with current Haloarcula and Halomicroarcula species (89.4-99.1% 16S rRNA and 87.6-95.0% rpoB' gene similarities), as revealed by phylogenetic analyses. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and AAI values among these six strains and current Haloarcula and Halomicroarcula species were 76.2-89.8%, 25.3-46.0%, and 70.3-89.7%, respectively, clearly below the species demarcation threshold. These six strains were distinguished from current Haloarcula and Halomicroarcula species according to differential phenotypic characteristics. Six novel species, Haloarcula halophila sp. nov., Haloarcula litorea sp. nov., Haloarcula rara sp. nov., Haloarcula halobia sp. nov., Haloarcula pelagica sp. nov., and Haloarcula ordinaria sp. nov., are proposed to accommodate strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T, respectively.


Assuntos
Haloarcula , Halobacteriaceae , Halobacteriales , Filogenia , RNA Ribossômico 16S/genética , DNA Arqueal/genética , Composição de Bases , Análise de Sequência de DNA , Ácidos Graxos/química , DNA Bacteriano , Técnicas de Tipagem Bacteriana
8.
Extremophiles ; 28(2): 28, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38890178

RESUMO

Four halophilic archaeal strains YCN1T, YCN58T, LT38T, and LT62T were isolated from Yuncheng Salt Lake (Shanxi, China) and Tarim Basin (Xinjiang, China), respectively. Phylogenetic and phylogenomic analyses showed that these four strains tightly cluster with related species of Halobacterium, Natronomonas, Halorientalis, and Halobellus, respectively. The AAI, ANI, and dDDH values between these four strains and their related species of respective genera were lower than the proposed threshold values for species delineation. Strains YCN1T, YCN58T, LT38T, and LT62T could be differentiated from the current species of Halobacterium, Natronomonas, Halorientalis, and Halobellus, respectively, based on the comparison of diverse phenotypic characteristics. The polar lipid profiles of these four strains were closely similar to those of respective relatives within the genera Halobacterium, Natronomonas, Halorientalis, and Halobellus, respectively. The phenotypic, phylogenetic, and genome-based analyses indicated that strains YCN1T, YCN58T, LT38T, and LT62T represent respective novel species within the genera Halobacterium, Natronomonas, Halorentalis, and Halobellus, for which the names Halobacterium yunchengense sp. nov., Natronomonas amylolytica sp. nov., Halorientalis halophila sp. nov., and Halobellus salinisoli sp. nov. are proposed, respectively.


Assuntos
Lagos , Filogenia , Lagos/microbiologia , Microbiologia do Solo , Halobacterium/genética , Halobacterium/isolamento & purificação , Genoma Arqueal , Halobacteriaceae/genética , Halobacteriaceae/isolamento & purificação , Halobacteriaceae/classificação
9.
J Phys Chem A ; 128(23): 4638-4650, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38832757

RESUMO

Alkanes, ideal raw materials for industrial chemical production, typically exhibit limited reactivity due to their robust and weakly polarized C-H bonds. The challenge lies in selectively activating these C-H bonds under mild conditions. To address this challenge, various C-H activation mechanisms have been developed. Yet, classifying these mechanisms depends on the overall stoichiometry, which can be ambiguous and sometimes problematic. In this study, we utilized density functional theory calculations combined with intrinsic bond orbital (IBO) analysis to examine electron flow in the four primary alkane C-H activation mechanisms: oxidative addition, σ-bond metathesis, 1,2-addition, and electrophilic activation. Methane was selected as the representative alkane molecule to undergo C-H heterolytic cleavage in these reactions. Across all mechanisms studied, we find that the CH3 moiety in methane consistently uses an electron pair from the cleaved C-H bond to form a σ-bond with the metal. Yet, the electron pair that accepts the proton differs with each mechanism: in oxidative addition, it is derived from the d-orbitals; in σ-bond metathesis, it resulted from the metal-ligand σ-bonds; in 1,2-addition, it arose from the π-orbital of the metal-ligand multiple bonds; and in electrophilic activation, it came from the lone pairs on ligands. This detailed analysis not only provides a clear visual understanding of these reactions but also showcases the ability of the IBO method to differentiate between mechanisms. The electron flow discerned from IBO analysis is further corroborated by results from absolutely localized molecular orbital energy decomposition analysis, which also helps to quantify the two predominant interactions in each process. Our findings offer profound insights into the electron dynamics at play in alkane C-H activation, enhancing our understanding of these critical reactions.

10.
Antonie Van Leeuwenhoek ; 117(1): 51, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38472444

RESUMO

The current species of Halosegnis and Salella within the class Halobacteria are closely related based on phylogenetic, phylogenomic, and comparative genomic analyses. The Halosegnis species showed 99.8-100.0% 16S rRNA and 96.6-99.6% rpoB' gene similarities to the Salella species, respectively. Phylogenetic and phylogenomic analyses showed that Salella cibi CBA1133T, the sole species of Salella, formed a single tight cluster with Halosegnis longus F12-1T, then with Halosegnis rubeus F17-44T. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and average amino acid identity (AAI) values between Salella cibi CBA1133T and Halosegnis longus F12-1T were 99.2, 94.2, and 98.6%, respectively, much higher than the thresholds for species demarcation. This genome-based classification revealed that the genus Salella should be merged with Halosegnis, and Salella cibi should be a later heterotypic synonym of Halosegnis longus. Halophilic archaeal strains DT72T, DT80T, DT85T, and DT116T, isolated from the saline soil of a tidal flat in China, were subjected to polyphasic taxonomic characterization. The phenotypic, chemotaxonomic, phylogenetic, and phylogenomic features indicated that strains DT72T (= CGMCC 1.18925T = JCM 35418T), DT80T (= CGMCC 1.18926T = JCM 35419T), DT85T (= CGMCC 1.19049T = JCM 35605T), and DT116T (= CGMCC 1.19045T = JCM 35606T) represent four novel species of the genera Halorussus, Halosegnis and Haloglomus, respectively, for which the names, Halorussus caseinilyticus sp. nov., Halorussus lipolyticus sp. nov., Halosegnis marinus sp. nov., and Haloglomus litoreum sp. nov., are proposed.


Assuntos
Halobacteriaceae , Análise de Sequência de DNA , Filogenia , RNA Ribossômico 16S/genética , Halobacteriaceae/genética , China , DNA , DNA Arqueal/genética , Ácidos Graxos/química , DNA Bacteriano/genética
11.
Curr Microbiol ; 81(7): 194, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38806737

RESUMO

Four halophilic archaeal strains, BCD28T, BND7T, PSR21T, and PSRA2T, were isolated from coastal and inland saline soil, respectively. The 16S rRNA and rpoB' gene sequence similarities among these four strains and current species of Halomarina were 95.9-96.6% and 86.9-90.3%, respectively. Phylogenetic and phylogenomic analyses revealed that these four strains tightly cluster with the current species of the genus Halomarina. The AAI, ANI, and dDDH values among these four strains and current species of Halomarina were 65.3-68.4%, 75.8-77.7%, and 20.3-22.0%, respectively, clearly below the threshold values for species demarcation. Strains BCD28T, BND7T, PSR21T, and PSRA2T could be differentiated from the current species of Halomarina based on the comparison of diverse phenotypic characteristics. The major polar lipids of these four strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), and four to five glycolipids. Phosphatidylglycerol sulfate (PGS) was only detected in strain BND7T. The phenotypic, phylogenetic, and genome-based analyses suggested that strains BCD28T (= CGMCC 1.18776T = JCM 34908T), BND7T (= CGMCC 1.18778T = JCM 34910T), PSR21T (= CGMCC 1.17027T = JCM 34147T), and PSRA2T (= CGMCC 1.17214T = JCM 34148T) represent four novel species of the genus Halomarina, for which the names Halomarina litorea sp. nov., Halomarina pelagica sp. nov., Halomarina halobia sp. nov., and Halomarina ordinaria sp. nov. are proposed.


Assuntos
DNA Arqueal , Filogenia , RNA Ribossômico 16S , Microbiologia do Solo , RNA Ribossômico 16S/genética , DNA Arqueal/genética , DNA Arqueal/química , Halobacteriaceae/classificação , Halobacteriaceae/genética , Halobacteriaceae/isolamento & purificação , Composição de Bases , Fosfolipídeos/análise , Análise de Sequência de DNA
12.
Angew Chem Int Ed Engl ; : e202408321, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926096

RESUMO

exo-6b2-Methyl-substituted pentabenzocorannulene (exoPBC-Me) was synthesized by the palladium-catalyzed cyclization of 1,2,3-triaryl-1H-cyclopenta[l]phenanthrene. Its bowl-shaped geometry with an sp3 carbon atom in the backbone and a methyl group located at the convex (exo) face was verified by X-ray crystallography. According to DFT calculations, the observed conformer is energetically more favorable than the endo one by 39.9 kcal/mol. Compared to the nitrogen-doped analogs with intact π-conjugated backbones (see the main text), exo-PBC-Me displayed a deeper bowl depth (avg. 1.93 Å), redshifted and broader absorption (250-620 nm) and emission (from 585 to more than 850 nm) bands and a smaller optical HOMO-LUMO gap (2.01 eV). exo-PBC-Me formed polar crystals where all bowl-in-bowl stacking with close π···π contacts is arranged unidirectionally, providing the potential for applications as organic semiconductors and pyroelectric materials. This unusual structural feature, molecular packing, and properties are most likely associated with the assistance of the methyl group and the sp3 carbon atom in the backbone.

13.
J Am Chem Soc ; 145(48): 26152-26159, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37992224

RESUMO

Despite the recent advancements of Cu catalysis for the cross-coupling of alkyl electrophiles and the frequently proposed involvement of alkyl-Cu(III) complexes in such reactions, little is known about the reactivity of these high-valent complexes. Specifically, although the reversible interconversion between an alkyl-CuIII complex and an alkyl radical/CuII pair has been frequently proposed in Cu catalysis, direct observation of such steps in well-defined CuIII complexes remains elusive. In this study, we report the synthesis and investigation of alkyl-CuIII complexes, which exclusively undergo a Cu-C homolysis pathway to generate alkyl radicals and CuII species. Kinetic studies suggest a bond dissociation energy of 28.6 kcal/mol for the CuIII-C bonds. Moreover, these four-coordinate complexes could be converted to a solvated alkyl-CuIII-(CF3)2, which undergoes highly efficient C-CF3 bond-forming reductive elimination even at low temperatures (-4 °C). These results provide strong support for the reversible recombination of alkyl radicals with CuII to form alkyl-CuIII species, an elusive step that has been proposed in Cu-catalyzed mechanisms. Furthermore, our work has demonstrated that the reactivity of CuIII complexes could be significantly influenced by subtle changes in the coordination environment. Lastly, the observation of the highly reactive neutral alkyl-CuIII-(CF3)2 species (or with weakly bound solvent molecules) suggests they might be the true intermediates in many Cu-catalyzed trifluoromethylation reactions.

14.
J Am Chem Soc ; 145(18): 10304-10313, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37099267

RESUMO

A series of hexapole helicenes (HHs) and nonuple helicenes (NHs) were prepared from 1,3,5-tris[2-(arylethynyl)phenyl]benzene through two steps, namely, iodocyclization and subsequent palladium-catalyzed annulation with ortho-bromoaryl carboxylic acids. The crucial advantages of this synthetic method are the facile introduction of substituents, high regioselectivity, and efficient backbone extension. Three-dimensional structures of three C1-symmetric HHs and one C3-symmetric NH were elucidated using X-ray crystallography. Unlike most conventional multiple helicenes, the HHs and NHs investigated herein possess a unique structural feature where some double helical moieties share a terminal naphthalene unit. Chiral resolution of a HH and an NH was successfully achieved, and the enantiomerization barrier (ΔH‡) of the HH was experimentally determined to be 31.2 kcal/mol. A straightforward method for predicting the most stable diastereomer was developed based on density functional theory calculations and structural considerations. It was found that the relative potential energies (ΔHrs) of all diastereomers for two HHs and one NH can be obtained using minimal computational effort to analyze the types, helical configurations, numbers, and ΔH(MP-MM)s [= H(M,P/P,M) - H(M,M/P,P)] of the double helicenyl fragments.

15.
J Antimicrob Chemother ; 78(8): 1891-1899, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37283194

RESUMO

BACKGROUND: Stenotrophomonas maltophilia is ubiquitous in the environment and is an important MDR opportunistic pathogen. Oxidative stress is an inevitable challenge to an aerobic bacterium. Accordingly, S. maltophilia has many capabilities to face variable oxidative stress. Some of the oxidative stress alleviation systems cross-protect bacteria from antibiotics. In our recent RNA-sequencing transcriptome analysis, we documented the increased expression of a three-gene cluster, yceA-cybB-yceB, in the presence of hydrogen peroxide (H2O2). The YceI-like, cytochrome b561 and YceI-like proteins encoded by yceA, cybB and yceB are located in the cytoplasm, inner membrane and periplasm, respectively. OBJECTIVES: To characterize the role of the yceA-cybB-yceB operon of S. maltophilia in oxidative stress tolerance, swimming motility and antibiotic susceptibility. METHODS: The presence of the yceA-cybB-yceB operon was verified by RT-PCR. The functions of this operon were revealed by in-frame deletion mutant construction and complementation assay. Expression of the yceA-cybB-yceB operon was assessed by quantitative RT-PCR. RESULTS: The yceA, cybB and yceB genes form an operon. Loss of function of the yceA-cybB-yceB operon compromised menadione tolerance, enhanced swimming motility and increased susceptibility to fluoroquinolone and ß-lactam antibiotics. The expression of the yceA-cybB-yceB operon was up-regulated by oxidative stress, such as H2O2 and superoxide, and not impacted by antibiotics, such as fluoroquinolone and ß-lactams. CONCLUSIONS: The evidence strongly supports the view that the physiological function of the yceA-cybB-yceB operon is to alleviate oxidative stress. The operon provides an additional example that oxidative stress alleviation systems can cross-protect S. maltophilia from antibiotics.


Assuntos
Stenotrophomonas maltophilia , Stenotrophomonas maltophilia/genética , Stenotrophomonas maltophilia/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Natação , Peróxido de Hidrogênio/farmacologia , Antibacterianos/farmacologia , Antibacterianos/metabolismo , Estresse Oxidativo , Fluoroquinolonas/metabolismo , Óperon
16.
Opt Express ; 31(20): 33015-33025, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37859090

RESUMO

The single photon scattering properties in a waveguide coupling to a giant atom with a three-level system are investigated theoretically. One of the transitions of the giant atom couples to the waveguide at two points while the other one is driven by a classical field. Using the analytical expressions of the single photon scattering amplitudes, the conditions for realizing perfect single photon nonreciprocal scattering are discussed in both Markovian regime and non-Markovian regime. In the Markovian regime, the perfect non-reciprocity can be realized by adjusting the external classical field, the energy dissipation of the giant atom, the phase difference between the two coupling strengths and the accumulated phase resulting from the photon propagating between the two coupling points. In the non-Markovian regime, the non-reciprocal scattering phenomenon becomes more abundant due to the time delay. However, the analytical results show that the perfect non-reciprocity can still be achieved. When the incident photon is resonant with the giant atom, the nonreciprocity can be switched by controlling the classical field. For the non-resonant single photon, one can adjust the Rabi frequency of the classical field to obtain the perfect non-reciprocal single photon transmission. Our work provides a manner to realize a frequency tunable single photon diode.

17.
Chemistry ; 29(22): e202300110, 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-36892141

RESUMO

A simple visible-light-induced CuCl-catalyzed synthesis was developed for highly functionalized carbon-centered compounds (α-alk/aryloxy-α-diaryl/alkylaryl-acetaldehydes/ketones) at room temperature using benzoquinone, alkyl/aryl alcohol, and alkyl/aryl terminal/internal alkynes. Late-stage functionalized compounds show good antifungal activities, especially against Candida krusei fungal strain, in in vitro experiments (the Broth microdilution method). Moreover, toxicity tests (zebrafish egg model experiments) indicated that these compounds had negligible cytotoxicity. The green chemistry metrics (E-factor value is 7.3) and eco-scale (eco-scale value is 58.8) evaluations show that the method is simple, mild, highly efficient, eco-friendly, and environmentally feasible.


Assuntos
Antifúngicos , Cobre , Animais , Antifúngicos/química , Catálise , Cloretos , Cobre/química , Halogênios , Cetonas/química , Temperatura , Peixe-Zebra , Oxirredução
18.
Artigo em Inglês | MEDLINE | ID: mdl-37204206

RESUMO

Four extremely halophilic archaeal strains, LYG-108T, LYG-24, DT1T and YSSS71, were isolated from salted Laminaria produced in Lianyungang and saline soil from the coastal beach at Jiangsu, PR China. The four strains were found to be related to the current species of Halomicroarcula (showing 88.1-98.5% and 89.3-93.6% similarities, respectively) as revealed by phylogenetic analysis based on 16S rRNA and rpoB' genes. These phylogenies were fully supported by the phylogenomic analysis, and the overall genome-related indexes (average nucleotide identity, DNA-DNA hybridization and average amino acid identity) among these four strains and the Halomicroarcula species were 77-84 %, 23-30 % and 71-83 %, respectively, clearly below the threshold values for species demarcation. Additionally, the phylogenomic and comparative genomic analyses revealed that Halomicroarcula salina YGH18T is related to the current species of Haloarcula rather than those of Halomicroarcula, Haloarcula salaria Namwong et al. 2011 is a later heterotypic synonym of Haloarcula argentinensis Ihara et al. 1997, and Haloarcula quadrata Oren et al. 1999 is a later heterotypic synonym of Haloarcula marismortui Oren et al. 1990. The major polar lipids of strains LYG-108T, LYG-24, DT1T and YSSS71 were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulphate, sulphated mannosyl glucosyl diether and additional glycosyl-cardiolipins. All these results showed that strains LYG-108T (=CGMCC 1.13607T=JCM 32950T) and LYG-24 (=CGMCC 1.13605=JCM 32949) represent a new species of the genus Halomicroarcula, for which the name Halomicroarcula laminariae sp. nov. is proposed; strains DT1T (=CGMCC 1.18928T=JCM 35414T) and YSSS71 (=CGMCC 1.18783=JCM 34915) also represent a new species of the genus Halomicroarcula, for which the name Halomicroarcula marina sp. nov. is proposed.


Assuntos
Haloarcula , Halobacteriaceae , Halobacteriales , Laminaria , Filogenia , RNA Ribossômico 16S/genética , Glicolipídeos/química , Ácidos Graxos/química , Composição de Bases , Análise de Sequência de DNA , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Cloreto de Sódio , Hibridização Genômica Comparativa , China , DNA Arqueal/genética
19.
Int J Syst Evol Microbiol ; 73(11)2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37917544

RESUMO

Two halophilic archaeal strains, ZS-10T and GSL13T, were isolated from the Zhoushan marine saltern in Zhejiang, and an inland saline soil from the Tarim Basin, Xinjiang, PR China, respectively. The cells of strain ZS-10T were pleomorphic while those of strain GSL13T were rod-shaped. Both of them stained Gram-negative and formed red-pigmented colonies on agar plates and their cells lysed in distilled water. The optimum growth of strain ZS-10T was observed at 40 °C, 3.4 M NaCl, 0.03 M MgCl2 and pH 7.5, while that of strain GSL13T was at 37 °C, 3.1 M NaCl, 0.5 M MgCl2 and pH 7.5. Phylogenetic and phylogenomic analyses indicated that these two strains were related to Salinigranum and Halohasta, respectively. Strains ZS-10T and GSL13T could be differentiated from the current members of Salinigranum and Halohasta based on the comparison of diverse phenotypic characteristics. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values among strain ZS-10T and current species of Salinigranum were 75.8-78.6 %, 80.6-81.9 % and 24.3-26.1 %, respectively. These values between strain GSL13T and current species of Halohasta were 78.4-80.8 %, 79.8-82.8% and 22.7-25.7 %, respectively, clearly below the threshold values for species demarcation. The polar lipids of strain ZS-10T were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me) and sulphated mannosyl glucosyl diether (S-DGD-1), while those of strain GSL13T were phosphatidic acid, PG, PGP-Me, phosphatidylglycerol sulphate and S-DGD-1. The polar lipid profile of strain GSL13T was identical to those of Halohasta, whereas strain ZS-10T did not contain the minor glycolipids detected in the current Salinigranum species. The phenotypic, phylogenetic and genome-based results suggested that strains ZS-10T (=CGMCC 1.12868T=JCM 30241T) and GSL13T (=CGMCC 1.15214T=JCM 30841T) represent two novel species, for which the names Salinigranum marinum sp. nov. and Halohasta salina sp. nov. are proposed.


Assuntos
Euryarchaeota , Halobacteriaceae , Halobacteriales , Cloreto de Sódio/análise , Filogenia , Ácidos Graxos/química , DNA Arqueal/genética , RNA Ribossômico 16S/genética , Composição de Bases , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , China , Glicolipídeos/química , Fosfatidilgliceróis/análise
20.
Artigo em Inglês | MEDLINE | ID: mdl-37728966

RESUMO

Five halophilic archaeal strains (AGai3-5T, KZCA101T, CGA3T, WLHS1T and WLHSJ1T) were isolated from salt lakes and soda lakes in PR China. These strains had low 16S rRNA gene similarities (91.3-96.0 %) to closely related species of the family Natrialbaceae and may represent a new genus of the family. Phylogenetic and phylogenomic analyses revealed that these strains formed a distinct clade, separate from the nearby genera Natronobiforma and Saliphagus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity (AAI) values among these five strains and the current members of the family Natrialbaceae were 72-90, 20-42 and 62-91 %, respectively, clearly below the threshold values for species demarcation. According to the critical value of AAI (≤76 %) proposed to differentiate genera within the family Natrialbaceae, it was further indicated that these strains represented a novel genus within the family. These strains could be distinguished from the related genera according to differential phenotypic characteristics. The major lipids of these strains were phosphatidic acid (PA), phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, mannosyl glucosyl diether (DGD-PA), sulphated DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. The phenotypic, chemotaxonomic, phylogenetic and phylogenomic features indicated that strains AGai3-5T (=CGMCC 1.16078T=JCM 33549T), KZCA101T (=CGMCC 1.17431T=JCM 35074T), CGA3T (=CGMCC 1.17463T=JCM 34318T), WLHS1T (=CGMCC 1.13780T=JCM 33562T) and WLHSJ1T (=CGMCC 1.13784T=JCM 33563T) represent five novel species of a new genus within the family Natrialbaceae, named Natronosalvus halobius gen. nov., sp. nov., Natronosalvus caseinilyticus sp. nov., Natronosalvus vescus sp. nov., Natronosalvus rutilus sp. nov. and Natronosalvus amylolyticus sp. nov., respectively.


Assuntos
Cyprinidae , Euryarchaeota , Halobacteriales , Animais , Lagos , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Ácidos Graxos/química , Aminoácidos
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