Microbe-induced gene silencing boosts crop protection against soil-borne fungal pathogens.

Small RNA (sRNA)-mediated trans-kingdom RNA interference (RNAi) between host and pathogen has been demonstrated and utilized. However, interspecies RNAi in rhizospheric microorganisms remains elusive. In this study, we developed a microbe-induced gene silencing (MIGS) technology by using a rhizospheric beneficial fungus, Trichoderma harzianum, to exploit an RNAi engineering microbe and two soil-borne pathogenic fungi, Verticillium dahliae and Fusarium oxysporum, as RNAi recipients. We first detected the feasibility of MIGS in inducing GFP silencing in V. dahliae. Then by targeting a fungal essential gene, we further demonstrated the effectiveness of MIGS in inhibiting fungal growth and protecting dicotyledon cotton and monocotyledon rice plants against V. dahliae and F. oxysporum. We also showed steerable MIGS specificity based on a selected target sequence. Our data verify interspecies RNAi in rhizospheric fungi and the potential application of MIGS in crop protection. In addition, the in situ propagation of a rhizospheric beneficial microbe would be optimal in ensuring the stability and sustainability of sRNAs, avoiding the use of nanomaterials to carry chemically synthetic sRNAs. Our finding reveals that exploiting MIGS-based biofungicides would offer straightforward design and implementation, without the need of host genetic modification, in crop protection against phytopathogens.

Molecularly imprinted Ag/Ag3VO4/g-C3N4 Z-scheme photocatalysts for enhanced preferential removal of tetracycline.

High selectivity and fast charge separation are two important factors for photocatalytic wastewater treatment. Herein, we prepared a molecular imprinted Ag/Ag3VO4/g-C3N4 photocatalyst (MIP) that exhibited great specific recognition ability along with excellent photocatalytic activity. The ultrathin g-C3N4 nanosheets with high surface are used to prepare. The Z-scheme Ag3VO4/g-C3N4 heterostructure and the surface plasmon resonance of the photoreduced Ag0 together contributed to the improvement of the separation efficiency of photogenerated electrons and holes. In addition, MIP provides the specific recognition ability to preferentially adsorb the target pollutant. The selectivity of photocatalysis was evaluated by the degradation of oxytetracycline and tetracycline solutions. Photoluminescence and transient photocurrent measurements further prove the improved charge separation efficiency of MIP. A plausible photocatalytic reaction mechanism is proposed based on electron spin resonance measurement and the active species trapping experiments, where indicates that the main active species of this photocatalytic process are O2- and h+. This research provides an effective strategy for the simultaneous enhancement of selectivity and activity via molecular imprinting.

Star-shaped poly(L-lactide)-b-poly(lactobionamidoethyl methacrylate) with porphyrin core: synthesis, self-assembly, singlet oxygen research and recognition properties.

Star-shaped porphyrin-cored poly(L-lactide)-b-poly(lactobionamidoethyl methacrylate) block copolymers (SPPLA-b-PLAMA) were synthesized via RAFT of unprotected Lactobionamidoethyl methacrylate (LAMA) in 1-methyl-2-pyrrolidinone (NMP) solution at 70 °C. The structure of this as-synthesized SPPLA-b-PLAMA block copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC), and Fourier transforms infrared. Moreover, under the irradiation, such SPPLA-b-PGAMA copolymer exhibits efficient singlet oxygen generation (0.17) and indicates high fluorescence quantum yields (0.20). Notably, with UV-vis investigation, SPPLA-b-PLAMA showed a very specific recognition with RCA120 lectin. This will not only provide potentially prophyrin-cored star-shaped SPPLA-b-PLAMA block copolymers for targeted photodynamic therapy, but also improve the physical, biodegradation, biocompatibility properties of PLA-based biomaterials.

Adsorption of lead(II) by silica/cell composites from aqueous solution: kinetic, equilibrium, and thermodynamics studies.

Silica/cell composites were prepared for the adsorption of lead ions, Pb(II), from aqueous solution in a batch system. The silica/cell composites possessed micropores, high surface area, and abundant functional groups. Adsorption performance was investigated by analyzing the effects of such factors as the initial pH, contact time with different initial concentration, and initial Pb(II) concentration at different temperature. The kinetic data were fitted to pseudo-second-order and intraparticle diffusion kinetic models. The results were better fitted by the pseudo-second-order kinetic model. Intraparticle diffusion increased with an increase of initial concentration and the sorption process was controlled by film diffusion. The Langmuir isotherm model was fitted to the experimental data significantly better than Freundlich and Dubinin-Radushkevich isotherm models. The maximum adsorption capacity was 97.10 mg g(-1), according to the Langmuir isotherm model. Thermodynamics parameters confirmed the spontaneous, endothermic, and entropy-gained nature within the studied temperature range (from 298 to 318 K). The composites could be effectively desorbed by the 2.0 mol L(-1) HNO3 solution and would be a potential adsorbent.

3-Carb-oxy-quinolin-1-ium-2-carboxyl-ate monohydrate.

The title compound, C(11)H(7)NO(4)·H(2)O, contains a 3-carb-oxy-quinolin-1-ium-2-carboxyl-ate (qda) zwitterion and one water mol-ecule. In the crystal, pairs of N-H⋯O hydrogen bonds link the mol-ecules into inversion dimers, and these dimers are further connected by O-H⋯O hydrogen bonds into a three-dimensional supra-molecular architecture. In addition, π-π inter-actions occur between pyridine and benzene rings from different qda ligands [centroid-centroid distance = 3.749 (1) Å] and the dihedral angles of the -CO(2)H and -CO(2) groups to the quinoline system are 8.47 (3) and 88.16 (6)°, respectively.

2,2'-Dimethyl-1,1'-[2,2-bis-(bromo-methyl)propane-1,3-di-yl]dibenzimidazole hemihydrate.

The title compound, C(21)H(22)Br(2)N(4)·0.5H(2)O, contains two benzimidazole groups which may provide two potential coordination nodes for the construction of metal-organic frameworks. The mean planes of the two imidazole groups are almost perpendicular, with a dihedral angle of 83.05 (2)°, and adjacent mol-ecules are linked into a one-dimensional chain by π-π stacking inter-actions between imidazole groups of different mol-ecules [centroid-to-centroid distances of 3.834 (2) and 3.522 (2) Å].

cyclo-Tetra-kis{µ-2,2'-dimethyl-1,1'-[2,2-bis-(bromo-meth-yl)propane-1,3-di-yl]di(1H-benzimidazole)-κN:N}tetra-kis-[bromidocopper(I)].

The title compound, [Cu(4)Br(4)(C(21)H(22)Br(2)N(4))(4)], features a macrocyclic Cu(4)L(4) ring system in which each Cu(I) atom is coordinated by one bromide ion and two N atoms from two 2,2'-dimethyl-1,1'-[2,2-bis-(bromo-meth-yl)propane-1,3-di-yl]di(1H-benzimidazole) (L) ligands in a distorted trigonal-planar geometry. The L ligands adopt either a cis or trans configuration. The asymmetric unit contains one half-mol-ecule with the center of the macrocycle located on a crystallographic center of inversion. Each bromide ion binds to a Cu(I) atom in a terminal mode and is oriented outside the ring. The macrocycles are inter-connected into a two-dimensional network by π-π inter-actions between benzimid-azole groups from different rings [centroid-centroid distance = 3.803 (5) Å.

Poly[(µ(2)-quinoline-3-carboxyl-ato-κN:O)(µ(2)-quinoline-3-carboxyl-ato-κN:O,O')cadmium].

In the title compound, [Cd(C(10)H(6)NO(2))(2)](n), the Cd(II) atom is coordinated by three O atoms and two N atoms from four quinoline-3-carboxyl-ate (L(-)) ligands, leading to a distorted trigonal-bipyramidal geometry. The L(-) ligands link the Cd(II) atoms into a plane parallel to (100), with one ligand being tridentate, coordinating via the N atom and chelating a second Cd atom, and the other being bidentate, bridging two Cd atoms via the N and one O atom.. This two-dimensional network extends into a double-layer network by π-π inter-actions, with centroid-centroid distances of 3.680 (2) and 3.752 (2) Å. Another type of π-π inter-action between pyridine rings [centroid-centroid distance = 3.527 (2) Å] leads to a three-dimensional supra-molecular architecture.

A novel rice gene, NRR responds to macronutrient deficiency and regulates root growth.

To better understand the response of rice to nutrient stress, we have taken a systematic approach to identify rice genes that respond to deficiency of macronutrients and affect rice growth. We report here the expression and biological functions of a previously uncharacterized rice gene that we have named NRR (nutrition response and root growth). NRR is alternatively spliced, producing two 5'-coterminal transcripts, NRRa and NRRb, encoding two proteins of 308 and 223 aa, respectively. Compared to NRRb, NRRa possesses an additional CCT domain at the C-terminus. Expression of NRR in rice seedling roots was significantly influenced by deficiency of macronutrients. Knock-down of expression of NRRa or NRRb by RNA interference resulted in enhanced rice root growth. By contrast, overexpression of NRRa in rice exhibited significantly retarded root growth. These results revealed that both NRRa and NRRb played negative regulatory roles in rice root growth. Our findings suggest that NRRa and NRRb, acting as the key components, modulate the rice root architecture with the availability of macronutrients.

Biosorption of Pb(II) by biomass of KC-2: kinetic, equilibrium and characteristic studies.

Performance and characteristics of biosorption of Pb(II) had been studied in a batch system using the fungal strain biomass, KC-2. The biosorption performance was investigated by analysing the effects of such factors as the initial pH, initial Pb(II) concentration, and contact time at 303 K. The maximum Pb(II) adsorption was obtained at pH 5.0. The experimental data were described by the pseudo first-order, pseudo second-order and intraparticle diffusion kinetic models, and were closely followed the pseudo second-order kinetic model. The equilibrium experimental data were well fitted to Langmuir model and the maximum biosorption capacity was 84.03 mg g(-1). The adsorption mechanism was examined by FTIR, SEM and EDAX analysis. Results indicated that carboxylic, hydroxyl and amine groups were involved in the biosorption and ion exchange mechanism existed.

Overexpression of an F-box protein gene reduces abiotic stress tolerance and promotes root growth in rice.

As one of the largest gene families, F-box domain proteins have important roles in regulating various developmental processes and stress responses. In this study, we have investigated a rice F-box domain gene, MAIF1. The MAIF1 protein is mainly localized in the plasma membrane and nucleus. MAIF1 expression is induced rapidly and strongly by abscisic acid (ABA) and abiotic stresses. MAIF1 expression is also induced in root tips by sucrose, independent of its hydrolytic hexose products, glucose and fructose, and the plant hormones auxin and cytokinin. Overexpression of MAIF1 reduces rice ABA sensitivity and abiotic stress tolerance and promotes rice root growth. These results suggest that MAIF1 is involved in multiple signaling pathways in regulating root growth. Growth restraint in plants is an acclimatization strategy against abiotic stress. Our results also suggest that MAIF1 plays the negative role in response to abiotic stress possibly by regulating root growth.

Extraction and determination of chloramphenicol in feed water, milk, and honey samples using an ionic liquid/sodium citrate aqueous two-phase system coupled with high-performance liquid chromatography.

A green, simple, non-toxic, and sensitive sample pretreatment procedure coupled with high-performance liquid chromatography (HPLC) was developed for the analysis of chloramphenicol (CAP) that exploits an aqueous two-phase system based on imidazolium ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim]BF(4)) and organic salt (Na(3)C(6)H(5)O(7)) using a liquid-liquid extraction technique. The influence factors on partition behaviors of CAP were studied, including the type and amount of salts, the pH value, the volume of [Bmim]BF(4), and the extraction temperature. Extraction efficiency of the CAP was found to increase with increasing temperature and the volume of [Bmim]BF(4). Thermodynamic studies indicated that hydrophobic interactions were the main driving force, although electrostatic interactions and salting-out effects were also important for the transfer of the CAP. Under the optimal conditions, 90.1% of the CAP could be extracted into the ionic liquid-rich phase in a single-step extraction. This method was practical when applied to the analysis of CAP in feed water, milk, and honey samples with a linear range of 2~1,000 ng mL(-1). The method yielded a limit of detection of 0.3 ng mL(-1) and a limit of quantification of 1.0 ng mL(-1). The recovery of CAP was 90.4-102.7% from aqueous samples of real feed water, milk, and honey samples by the proposed method. This novel process is much simpler and more environmentally friendly and is suggested to have important applications for the separation of antibiotics.

Poly[[µ(2)-2,2'-diethyl-1,1'-(butane-1,4-di-yl)diimidazole-κN:N](µ(2)-5-hydroxy-isophthalato-κO:O)zinc].

In the title coordination polymer, [Zn(C(8)H(4)O(5))(C(14)H(22)N(4))](n), the Zn(II) cation is coordinated by an O(2)N(2) donor set in a distorted tetra-hedral geometry. The Zn(II) ions are linked by µ(2)-OH-bdc (OH-H(2)bdc = 5-hy-droxy-isophthalic acid) and bbie ligands [bbie = 2,2'-diethyl-1,1'-(butane-1,4-di-yl)diimidazole], forming a two-dimensional layer parallel to the ab plane. The layers are further connected through intermolecular C-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional supramolecular structure. In the bbie ligand, the two C atoms in the ethyl group are each disordered over two positions with a site-occupancy ratio of 0.69:0.31.

Poly[[µ-2,2'-diethyl-1,1'-(propane-1,3-di-yl)di-1H-imidazole-κN:N](µ-5-hy-droxy-isophthalato-κO:O)zinc].

In the title coordination polymer, [Zn(C(8)H(4)O(5))(C(13)H(20)N(4))](n), the Zn(II) ion is coordinated by an O(2)N(2) donor set in a distorted tetra-hedral geometry. The Zn(II) ions are connected by 5-hy-droxy-isophthalate (hbdc) and 2,2'-diethyl-1,1'-(propane-1,3-di-yl)di-1H-imidazole (pbie) ligands, forming a threefold inter-penetrating diamondoid framework. In the pbie ligand, one of the ethyl-imidazole groups is disordered over two positions, with a site-occupancy ratio of 0.670 (9):0.330 (9). An inter-molecular O-H⋯O hydrogen bond is formed between the hy-droxy and carboxyl-ate groups of the hbdc ligands.

Poly[[diaqua-bis-(µ(3)-3-carboxyl-ato-4-hy-droxy-benzene-sulfonato)-tri-µ(2)-pyrazine-tetra-silver(I)] dihydrate].

The title coordination polymer, {[Ag(4)(C(7)H(4)O(6)S)(2)(C(4)H(4)N(2))(3)(H(2)O)(2)]·2H(2)O}(n), contains two independent Ag(I) ions. One Ag(I) ion is coordinated by one O atom from a 3-carboxyl-ato-4-hy-droxy-benzene-sulfonate (L) ligand, two N atoms from two pyrazine ligands and a water mol-ecule. The other Ag(I) ion is coordinated by two O atoms from two L ligands and one N atom from a pyrazine ligand. One of the pyrazine ligands lies on an inversion center. The L and pyrazine ligands link the Ag(I) ions into polymeric layers parallel to the ac plane. The layers are connected by inter-molecular O-H⋯O hydrogen bonds. An intra-molecular O-H⋯O hydrogen bond is also present in the L ligand.

[Analysis of properties of cadmium adsorption onto whisker surface ion-imprinted polymer by inductively coupled plasma atomic emission spectrometry].

A new type of surface ion-imprinted polymer was synthesized in aqueous media with sodium trititanate whisker in the presence of Cd(II), chitosan and gamma-glycidoxypropyl trimethoxysilane (KH-560). A batch of adsorption experiments were performed to evaluate its adsorption of Cd(II) using inductively coupled plasma atomic emission spectrometry (ICP-AES). The factors affecting adsorption capacity, including pH and sorbent amount, were discussed. The adsorption kinetics and adsorption isothermals were also obtained. The Langmuir isotherm can fit in the experimental equilibrium data. Under the optimum conditions, the value of the adsorption was above 99%, and the maximum adsorption capacity was 52.34 mg x g(-1). In accordance with the parameters distribution coefficient (K(d)) and selectivity coefficient (K), the selectivity for Cd(II) of the prepared imprinted polymer was estimated. Finally, the adsorption mechanism was discussed and the detection limit of 0.024 microg x mL(-1) with the relative standard deviation (RSD) of 1.74% (c = 1.0 microg x mL(-1), n = 13) for Cd(II) was obtained. Results showed that the surface Cd(II)-imprinted polymer was a solid sorbent with high efficiency, low-cost, convenient separation/enrichment for environmental trace Cd(II).

[Studies on TCs-Fe(III) system separation/enrichment of trace tetracyclines antibiotic by combination ionic liquid [Hmim]PF6 solvent sublation with fluorescence spectroscopy determination].

It is the first time ionic liquid was applied to gas solvent sublation, which established a new method for separation/enrichment of tetracyclines (TCs) antibiotic based on ionic liquid gas solvent sublation. The optimizing experimental conditions were as follows: the mixture of ionic liquid 1-hexyl-3-methylimidazo lium hexafluorophosphats and ethyl acetate ([Hmim] PF6-EA, phi = 1/0.9) can be used as flotation solvent, Fe(III) ion was as trapping agent, pH of test solution was 7.6, the gas flow rate was 40 mL x min(-1), and the flotation time was 50 min. The complexes of TCs- Fe (III) were pre-concentrated in the [Hmim] PF6-EA layer and this was used to determine analytes by fluorescence method directly. The linear regression equation was F = 246.5c+4.32 (c: microg x 10 mL(-1)), and correlation coefficient was 0.999 1. Recoveries between 94.2% and 100.4% were achieved from surface water and sediment samples in ponder by using this method and the relative standard deviation of 5 microg x mL(-1) TCs for 5 parallel determinations was less than 3.2%. FTIR spectroscopy demonstrated that no chemical (bonding) interactions occurred between the ionic liquid and the complexes functional groups, and the ionic liquid was only solvent. The experimental result indicated that utilizing ionic liquid to float TCs in environmental sample is feasible.

[Study on the adsorption behavior of nickel on potassium tetratitanate whisker by flame atomic absorption spectrometry].

The adsorption behavior of Ni (II) on potassium tetratitanate whisker was studied systemically by FAAS, seeing about the reasons for absorption, disentanglement and the effect of interfering ions on the recovery. The preconcentration method was simple, quick and had good selectivity. The adsorption rate of Ni(II) by potassium tetratitanate whisker was 100% at pH 5.0 and Ni(II) could be eluted from potassium tetratitanate whisker with hydrochloric acid (C: 0.5 mol x L(-1)), shake time exceeding 5 min, stick time exceeding 1.5 h, and the disentanglement ratio exceeding 90%. The relative standard deviation (RSD) was 2.6%. The results obtained indicate that the potassium tetratitanate whisker has good regenerate capability.

Extraction and mechanism investigation of trace roxithromycin in real water samples by use of ionic liquid-salt aqueous two-phase system.

The ionic liquid, as a green solvent, has several advantages over the organic solvents in traditional liquid-liquid extraction. Aqueous two-phase system (ATPS) consisting of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoraborate, [Bmim]BF(4)) and Na(2)CO(3), which is a novel, simple, non-toxic and effective sample pretreatment technique coupled with molecular fluorescence spectrophotometry, was developed for the simultaneous separation, enrichment and rapid analysis of roxithromycin. The extraction yield of roxithromycin in [Bmim]BF(4)-Na(2)CO(3) aqueous two-phase system is influenced by the types of salts, concentrations of Na(2)CO(3) and [Bmim]BF(4), as well as the extracting temperature. Under the optimum conditions, the average extraction efficiency is up to 90.7%. The mechanism of ionic liquid-salt ATPS formation was discussed by hydration theory, and the extraction mechanism of the [Bmim]BF(4)-salt ATPS was investigated by FT-IR spectroscopy and UV-vis spectroscopy. The results demonstrate that no chemical (bonding) interactions are observed between ionic liquid and roxithromycin, while the nature properties of the roxithromycin are not altered. This method was practical when applied to the analysis of roxithromycin in real water samples with the detection limit of 0.03 microg mL(-1), relative standard deviation (RSD) of 1.9% (n=13), and linear ranges of 1.00-20.00 microg mL(-1). The proposed extraction technique will be promising in the separation of other small biomolecules.

[ICP-AES determination of Cu2+, Pb2+ and Cd2+ with adsorption behavior of potassium hexatitanate whisker].

A new method for the determination of free Cu2+, Pb2+ and Cd2+ in environmental sample using potassium hexatitanate whisker as a solid-phase extractant and inductively coupled plasma-atomic emission spectrometry (ICP-AES) as a sensitive detector has been developed. The adsorption rate of Cu2+, Pb2+ and Cd2+ by potassium hexatitanate whisker was 98% at pH 5.0, and Cu2+, Pb2+ and Cd2+ could be eluted from potassium hexatitanate whisker with HNO3 (C: 3 mol x L(-1)). The Cu2+, Pb2+ and Cd2+ in environmental samples were preconcentrated with potassium hexatitanate whisker and determined by ICP-AES, the detection limits of Cu2+, Pb2+ and Cd2+ (3sigma, n = 9) were 0.007 1, 0.006 8 and 0.007 1 microg x mL(-1), and the relative standard deviations (RSD) were 0.63%, 0.61% and 0.50%, respectively. The method was applied to the determination of analytes in real samples, such as chrysanthemum and loquat leaf. And good results were obtained (recoveries were 90%-102.9%). The results obtained indicate that the potassium hexatitanate whisker has good regenerate capability.