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In this study, the biotite weathering activities of strain S41 and mutants with deletion of the iron response regulator genes fur, rirA, and irr were compared. S41ΔrirA had a 35%–60% increase in Fe and Al concentrations, a 95%–112% increase in siderophore production, and a 18%–22% increase in EPS concentration, while S41Δirr had a 29%–48% decrease in Fe and Al concentrations and a 32%–42% decrease in siderophore production, compared with strain S41. Under iron-sufficient conditions, S41ΔrirA had a 1.5-fold–2.7-fold increase in siderophore production, while there was similar siderophore production between strain S41 and S41Δirr. Under iron-limited conditions, S41Δirr had a 34%–40% decrease in siderophore production compared with strain S41. The expression of genes related to the synthesis of siderophores, iron uptake and transporters, and EPS production in strain S41 significantly increased in iron-limited conditions compared with that in iron-sufficient conditions. The expression of genes associated with the synthesis of siderophores and iron uptake and transporters significantly increased in S41ΔrirA in iron-sufficient and iron-limited conditions but decreased in S41Δirr in iron-limited conditions. Our results suggested that rirA- and irr-modulated multiple genes may be related to the mineral weathering activities of strain S41. [ABSTRACT FROM AUTHOR]

Eolian sand is widely distributed in desert areas, and can easily trigger sandstorms under the combined effects of wind and thermal conditions. In this paper, an eolian sand solidification test via microbially induced calcium carbonate (CaCO3) precipitation (MICP) was conducted to explore prospective applications of MICP in the field of dust prevention and sand fixation. A bacterial growth test and a MICP mineralization reaction test were performed based on the response surface method and an orthogonal experiment. Based on eolian sand solidification test, the effects of cementation number and dry density on the permeability and strength characteristics of solidified eolian sand, as well as the content of CaCO3 generated were analyzed. The results showed that the bacteria grew best at a temperature of 35 °C, a pH of 9, and a shaking frequency of 170 rpm. Both urease activity and bacterial concentration increased as the temperature and pH increased but showed a trend of rising before falling as the shaking grew faster. The optimal conditions for MICP mineralization were a bacterial concentration of OD600=1.5, a consolidating fluid concentration of 1 mol/L, a reaction time of 16 h, a pH of 9, and a temperature of 25 °C. The permeability coefficient of solidified eolian sand decreased as the dry density and the number of cementations increased, whereas the CaCO3 content increased with the number of cementations. As the number of cementations increased, the unconfined compressive strength (UCS) of eolian sand initially rose before stabilizing and then increasing again. The CaCO3 content had a positive relationship with UCS, which with the correlation coefficient reached 0.80. [ABSTRACT FROM AUTHOR]

A quinoline-containing semi-salamo-type ligand, HL, was synthesized and a dinuclear Ni(II) complex, [Ni2(L)2(NCS)2], was produced. The complex was experimentally analyzed by elemental analysis, fluorescence, and UV–Vis spectroscopy. X-ray single crystal diffraction experiments showed that the complex is a six-coordinate, structurally symmetric, phenoxy-bridged dinuclear Ni(II) dimer with the participation of SCN− in the coordination to satisfy charge neutrality. The self-assembly forms a 2-D supramolecular network structure through hydrogen bonding and π⋯π interactions. DFT calculations were performed on the complex to analyze its energy gaps, and UV–Vis experiment was verified by TD-DFT calculation. In addition, close intermolecular contacts were investigated by Hirshfeld surface analysis to quantify the crystal structure interaction. [ABSTRACT FROM AUTHOR]

Centrosymmetric homopolynuclear Cu(II) and Co(II) chelated complexes, [Cu2(L)(H2O)2] (1) and [Co4(L)(μ-OAc)2(CH3OH)4(OAC)2]⋅2CH2Cl2 (2), were synthesized using a new symmetrical methoxy-disubstituted bis(salamo)-type ligand, H4L, with Cu(II) and Co(II) salts in organic solvents. Complexes 1 and 2 were structurally characterized by single-crystal X-ray crystallography. The results indicated that 1 is a five-coordinate dinuclear structure containing Cu(II) and 2 is a tetranuclear Co(II) complex with two distinct six-coordinate environments. Furthermore, 1 and 2 pack into three-dimensional and two-dimensional extended networks, respectively. The UV–Vis spectra, IR spectra, and Hirshfeld surface analyses of the complexes were carried out to further characterize the coordination between H4L and the metal(II) ions. Fluorescence methods were used to interrogate the coordination, where changes in emission with varied amounts of ligand supported solution-phase coordination ratios of H4L with Cu(II) ion of 1:2 and with Co(II) ion of 1:4, respectively. [ABSTRACT FROM AUTHOR]

New di- and tetranuclear Cu(II) complexes, [Cu2(HL)Cl2(MeOH)]·MeOH·2CH2Cl2 (1) and [Cu4(L)2(MeOH)2](NO3)2·EtOH (2), have been synthesized from CuCl2·2H2O, Cu(NO3)2·3H2O and a symmetric 5-bromosalicylaldehyde-decorated bis(salamo)-like ligand (H3L, (1E,3E)-2-hydroxy-5-methylisophthalaldehyde O,O-di(2-((((E)-5-bromo-2-hydroxybenzylidene)amino)-oxy)ethyl)dioxime), and characterized by elemental analyses, IR and UV–vis spectra. Single crystal structure analyses showed a dinuclear Cu(II) structure for 1 and a tetranuclear Cu(II) structure for 2. In 1, two Cu(II) ions are on one side of the double N2O2 cavities, and the phenol proton in the other cavity is attached. In 2, four Cu(II) ions are located in four N2O2 cavities of two fully deprotonated L3− units, giving a centrosymmetric double helix structure. The Hirshfeld surfaces analyses, Interaction Region Indicator (IRI), and DFT computations of H3L, 1, and 2 were studied. In addition, the electrochemical and fluorescence properties of 1 and 2 were also investigated. [ABSTRACT FROM AUTHOR]

Two solvent-induced bis(phenoxo)-acetate-bridged binuclear Ni(II) complexes, [Ni2(L)(µ-OAc)(CH3OH)] (1) and [Ni2(L)(µ-OAc)(H2O)] (2), were synthesized with a bis(salamo)-like ligand H3L and Ni(OAc)2·4H2O in two different alcohol solvents (methanol and ethanol). Complexes 1 and 2 were described by elemental analyses, single crystal X-ray diffraction, IR spectra, UV–vis spectra and fluorescence spectra. Complexes 1 and 2 have analogous crystal structures, but the non-covalent interactions are distinct. The one-dimensional chain of 1 is formed by π–π interactions, and the three-dimensional supramolecular network structure of 2 is formed by intermolecular hydrogen bonding interactions. In addition, fluorescence experiments indicated that the fluorescence of 1 and 2 undergoe a significant quenching compared to H3L. Intermolecular forces were investigated using Hirshfeld surface analysis. DFT calculations showed that 1 and 2 have high chemical reactivity and low kinetic stability. [ABSTRACT FROM AUTHOR]

A penta-coordinated dinuclear Zn(II) complex, [Zn2(L)(μ-PhCOO)(EtOH)] (1), and a hexa-coordinate tetranuclear Cd(II) complex, [{Cd2(L)(EtOH)(η-OAc)}2]·2CH2Cl2 (2), have been synthesized by reactions of a single-armed salamo-based ligand, H3L, and two kinds of transition metal salts, (Zn(NO3)2·6H2O and Cd(OAc)2·2H2O), respectively. Complexes 1 and 2 have been characterized by elemental analyses, single crystal X-ray diffraction, IR spectra and UV-Vis spectra. Complex 1 is composed of a totally deprotonated ligand (L)3- moiety, two Zn(II) ions, one μ-PhCOO- counter-anion and one coordinated ethanol molecule. The (L)3- unit packages two Zn(II) ions, the μ-PhCOO- counter-anion bridges two adjacent Zn(II) ions and one ethanol molecule coordinates with the Zn2 ion, so that both Zn(II) ions are penta-coordinated with slightly distorted trigonal bipyramidal configurations, and the τ5 values of Zn1 and Zn2 are 0.86 and 0.65, respectively. Complex 2 consists of two discrete and similar electroneutral tetra-nuclear units, 2 A and 2B, and two crystallized dichloromethane molecules. Each unit has a symmetric structure that is made up of two completely deprotonated ligand (L)3- moieties, four Cd(II) ions, two η-OAc- counter-anions and two coordinated ethanol molecules. Fluorescence properties and Hirshfeld surfaces analyses have been studied as well. [ABSTRACT FROM AUTHOR]

A symmetrical N2O2-tetradentate dioxime chemical sensor H2L was synthesized for the first time. The sensor H2L can identify S2– ion with dual channels of fluorescence–ultraviolet spectra, and through the calculation of binding constant and detection limit of L-S system, it was showed that H2L can detect S2– ion with high efficiency and specificity. pH response experiments were carried out on L-S system and H2L to explore the pH range recognized by them. The recognition mechanism was determined by 1H NMR titration experiment. At the same time, a new method of macro recognition by means of naked eye recognition (under natural light and ultraviolet light of 365 nm) and filter paper recognition was developed. The practical application of the sensor H2L to detect H2S was evaluated in actual water samples and identification experiment of H2S. [ABSTRACT FROM AUTHOR]

The coordination behaviors of asymmetric quinoline-decorated half-salamo-type ligand HL1 with Cu(NO3)2·3H2O and Cu(OAc)2·H2O were studied. Two Cu(II) complexes, [Cu(L1)(NO3)]·CH3CH2OH (1) and [Cu2(L2)2] (2), were isolated and characterized by X-ray crystallography, FTIR, UV–vis, and fluorescence spectroscopies. Structural analyses showed that 1 is a mononuclear species, whereas 2 is a binuclear entity. Spontaneous cleavage along the oxime N-O bond close to quinoline ring of the ligand HL1 occurred upon reaction with Cu(OAc)2·H2O, yielding an unexpected complex 2. Moreover, DFT theoretical calculations and Hirshfeld surfaces analyses of the ligand HL1 and its corresponding Cu(II) complexes were investigated in detail. [ABSTRACT FROM AUTHOR]

A naphthol-functionalized bis(salamo)-like chromogenic and fluorogenic probe (TBS) was designed and synthesized for efficient double-channel detection of hydrogen sulfide (H2S). The probe TBS was characterized through various spectroscopic techniques. From both visible light and 365 nm UV light, TBS could have naked-eye recognition of H2S with obvious color change. In comparison with some chemical probes, the probe TBS could selectively monitor H2S with detection limit as low as 0.71 μM, which could serve as a promising candidate for detecting H2S in real world sampling. Beyond that, the sensing mechanism toward H2S was fully validated by 1H NMR, mass spectra (ESI-MS) as well as UV titration. Density-functional theory and time-dependent density-functional theory calculations were also carried out to further explain the photophysical behavior of the probe TBS with H2S. Finally, the probe TBS could be utilized as sulfide-targeted probe in a practical sample. [ABSTRACT FROM AUTHOR]

Two structurally different Cu(II) and Co(II) complexes, [Cu(L)] (1) and [Co2(L)2]⋅2CH3OH (2), constructed from a new polyhalogen-substituted unsymmetric salamo-based ligand (H2L, 4-chloro-4′-bromo-6-bromo-6′-tert-butyl-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) were synthesized by wet-chemical methods. Complexes 1 and 2 were characterized through elemental analyses, IR and UV-vis spectroscopies and single crystal X-ray crystallography. In addition, the differences of the structures, electronic absorption characteristics and fluorescence property transitions from the ligand to complexes 1 and 2 were studied. The largest difference is that the ligand H2L can react with M(OAc)2 (M = Cu(II) and Co(II)) to give two complexes with distinct structures and behaviors. There are two chemically identical but crystallographically independent structural units (molecules A and B) in 1. Moreover, each Cu(II) ion (Cu1 or Cu2) is four-coordinate and possesses a square planar geometry, but both Co(II) ions of 2 are bridged by phenoxide ions and possess five-coordinate trigonal bipyramidal configurations. At the same time, Hirshfeld surface analyses showed there are short-range interaction features from the ligand to complexes 1 and 2, the O···H/H···O interactions of the ligand are significantly stronger than those of 1 and 2. [ABSTRACT FROM AUTHOR]

A relatively rigid acyclic salamo-type ligand H2L and its square planar Cu(II) complex, [Cu(L)]·CH3OH, were synthesized and characterized by X-ray crystallography, as well as Fourier-transform infrared spectra, UV–Vis spectra, Hirshfeld surface analyses and DFT calculations. The ligand crystallizes in monoclinic space group P 21/c and has pairs of intramolecular hydrogen bonds between the oxime nitrogen atoms and the hydroxyl groups. The Cu(II) complex crystallizes in the monoclinic space group P 21/c. The Cu(II) ion is located in the N2O2 cavity of the fully deprotonated salamo-type ligand (L)2− unit, thus forming a four-coordinate distorted square planar geometry. At the same time, a belt-like, 2-D supramolecular structure is formed by the interaction of intermolecular hydrogen bonds, and the intermolecular interaction force is quantitatively analyzed by Hirshfeld surfaces. Significantly, fluorescence properties of the ligand and its Cu(II) complex were also studied. The coordination ratio of the Cu(II) complex was proved by UV–Vis and fluorescence titration experiments. [ABSTRACT FROM AUTHOR]

Two new coordination polymers (CPs), [Zn(HL)2(bipy)]n·2nCH3OH (Zn(II)-CP) and [Cd(HL)2(bipy)]n (Cd(II)-CP), were synthesized from a nonsymmetric salamo-based ligand, 4-chloro-4′-bromo-6-bromo-6′-tert-butyl-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L). Single crystal X-ray diffraction analysis showed that both Zn(II) and Cd(II) coordinate with the two semi-deprotonated ligands (HL)− and two 4,4′-bipyridine (bipy) auxiliary ligands, yielding slightly twisted octahedral configurations. The two one-dimensional (1-D) chain polymers are further connected by hydrogen bonds (H-bonds) to form interesting 3-D supramolecular structures. These intermolecular interactions and molecular stability were investigated by Hirshfeld surface analyses and Density Functional Theory (DFT) calculations. Luminescent studies show that these two CPs have potential application as light emitting devices. [ABSTRACT FROM AUTHOR]

Three phenolic compounds (±1 and 2) including a pair of new enantiomers were isolated from the sclerotia of Inonotus obliquus. Their structures were assigned by extensive spectroscopic analyses. All the compounds were evaluated for the neuroprotective activity against oxidative damage on human neuroblastoma SH-SY5Y cells induced by H2O2. Compound 2 showed remarkable neuroprotective effect and significantly improved the cell viability of SH-SY5Y cells treated by H2O2. [ABSTRACT FROM AUTHOR]

d-Block transition metal(II)-lanthanide(III) (3d-4f) hetero‐trinuclear [Cu(II)2Ln(III)] (Ln = La and Ce) complexes [Cu2La(L)(ƞ2-NO3)3(CH3OH)2]·2CH3OH (1) and [Cu2Ce(L)(ƞ2-NO3)3(CH3OH)2]·2CH3OH (2) are described, both of which are formed by a flexible symmetrical bis(salamo)-type ligand H4L. The two 3d-4f complexes have been synthesized and characterized by elemental analyses, IR spectra and UV–Vis spectroscopy. The crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction analyses. In 1 and 2, each Cu(II) ion (Cu1 or Cu2) is located in the N2O2 cavity of an (L)4− unit, while the apex is occupied by one oxygen atom of the coordinated methanol molecule, forming a penta-coordinated square pyramidal geometry. The lanthanide(III) (La or Ce) ion is located in the O6-donor coordination sphere of the completely deprotonated (L)4− unit and coordinated with the other six oxygen atoms of the three nitrate ligands to form a twelve-coordinated icosahedron. At the same time, the supramolecular structures are formed by intermolecular hydrogen bonding interactions and quantitatively determined by Hirshfeld surfaces analyses. Fluorescence properties and DFT calculations of 1 and 2 were also studied. [ABSTRACT FROM AUTHOR]

A bis(half-salamo)-type chemosensor LPBHSbased on phenanthroline, which can identify multiple targets continuously, was synthesized. The chemosensor LPBHS utilizes the N3O cavities to combine with metal cations, and further identify the anions after the complexes have been formed. The chemosensor LPBHS has an O-phenanthroline unit with excellent luminescence, so that the strong fluorescence of the chemosensor LPBHS can be observed under 365 nm UV light. The quenching of luminescence occurs after the introduction of Cu2+ and Co2+ into the chemosensor LPBHS, which can be identified in natural light by observing the change in color of the solution with the naked eye. The LPBHS-Cu2+ complex further recognizes HSˉ and PPi (pyrophosphoric acid), and strong luminescence are also observed under UV light after the addition of HSˉ and PPi to LPBHS-Cu2+. HSˉ and PPi can also be identified by the change in color of the solution under natural light with the naked eye. Using the strong fluorescence emission of LPBHS, a test strip was developed to detect Cu2+ and Co2+ rapidly, and the quenching of fluorescence was clearly observed under UV light. HSˉ and PPi can be further identified by the phenomenon of fluorescence recovery after Cu2+ detection on the test strip. [ABSTRACT FROM AUTHOR]

Three new dimeric 2-(2-phenylethyl)chromones crassin I ∼ K (1–3), together with one known analogue (4), were isolated from the artificial holing agarwood originating from Aquilaria sinensis. Their structures including the absolute configuration were elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR, ECD), and HRESIMS analysis, as well as by comparison with the literature data. Compounds 1 and 2 exhibited weak acetylcholinesterase inhibitory activity. [ABSTRACT FROM AUTHOR]

During the course of searching for structurally interesting and bioactive compounds, a further chemical investigation of the leaves of Heynea trijuga Roxburgh was performed, which led to the isolation of a new ergostane derivative, named 3β, 4β, 20S-trihydroxyergosta-5, 24(28)-dien-16-one (1), together with five known sterides (3β, 23S)-ergosta-5, 24(28)-diene-3, 23-diol (2), ergosta-5, 24(28)-diene-3β-diol (3), stigmast-5-ene-3β, 7α-diol (4), sitoindoside I (5) and stigmast-3β, 5α, 6β-triol (6). The structure of the new compound was elucidated using a combination of 1 D, 2 D NMR techniques and HR-EI-MS analyses. All the compounds were evaluated for cytotoxic activity against tumor cell line BEL-7402 by MTT method. [ABSTRACT FROM AUTHOR]

A new salamo-based ligand and its two new dinuclear complexes [{Co(L)}2(4,4′-bipy)] (1) and [{Cu(L)}2] (2), were designed and self-assembled, and characterized by elemental analyses, FT-IR, UV–vis absorption spectroscopy and X-ray crystallography. In 1, two [Co(L)] units are bridged by the auxiliary bidentate ligand 4,4′-bipy with nitrogen-donor atoms to form a centrosymmetric dimeric structure. Both Co(II) ions are five-coordinate and possess distorted trigonal bipyramidal configurations. Complex 2 is composed of two Cu(II) ions and two completely deprotonated ligand (L)2– units. Interestingly, the two [Cu(L)] units form a dimer bridged by two oxime O atoms. This structure is rare in reported salamo-based Cu(II) complexes. Both Cu(II) ions are five-coordinate and possess distorted tetragonal pyramidal geometries. Hirshfeld surface analyses showed that the O–H/H–O interactions of 1 and 2 are weaker than that of H2L. This phenomenon indicates that H2L forms corresponding complexes with the Co(II) and Cu(II) ions through the deprotonation of phenolic hydroxyl groups. The fluorescence spectra showed that the fluorescence of the ligand is almost completely quenched due to the coordination of the Cu(II) ions with H2L. DFT calculations show that 1 and 2 have higher chemical stability than that of H2L. [ABSTRACT FROM AUTHOR]

Three new 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones and one new dimeric 2-(2-phenylethyl)chromone were isolated from the agarwood of Aquilaria crassna Pierre ex Lecomte in Laos. The structures of the isolates were elucidated by spectroscopic methods, and their configurations were determined via ROESY correlations, 3JH-H coupling constants analyses, comparisons of chemical shifts and specific rotations with known compounds, and ECD calculation in the case of 1. Compounds 1–4 were evaluated for their cytotoxicity. Compounds 1 and 2 exhibited weak cytotoxicity toward HeLa cell line (IC50: 49.8 ± 1.2 μM) and K562 cell line (IC50: 42.66 ± 0.47 μM), respectively. [ABSTRACT FROM AUTHOR]

Abstract The oriental armyworm, Mythimna separata has led to great economic losses of corn in China. The main method to control this pest relies on chemical insecticides. Plenty of genes in armyworm can be activated in response to insecticides. In this study, the critical genes involved in detoxification of chlorantraniliprole in armyworm were investigated using RNA-seq (transcriptome sequencing), digital gene expression profiles, and functional identification by RNA interference (RNAi) technology. The de novo assembly of the transcriptomes was achieved based on Illumina short-read sequencing technology in M. separata. There were 70,845 unigenes produced and 35,327 (49.86%) annotated. 748 unigenes were significantly up-expressed and 741 were significantly down-expressed in chlorantraniliprole treatment group compared to the control group. Silencing of cytochrome B6-F (CYB6), and long chain fatty acid CoA ligase 4 (CoA) of the top 18 highly expressed genes selected in chlorantraniliprole treatment group, resulted in more significant sensibility of M. separata to chlorantraniliprole, growth retardation and antifeedant phenomenon, which indicated that both CYB6 and CoA were most possibly responsible for chlorantraniliprole metabolism/detoxication. [ABSTRACT FROM AUTHOR]