Las-like quorum-sensing system negatively regulates both pyoluteorin and phenazine-1-carboxylic acid production in Pseudomonas sp. M18

A las-like quorum-sensing system in Pseudomonas sp. M18 was identified, which consisted of lasI and lasR genes encoding LuxI-LuxR type regulator. Several functions of the las system from strain M18 were investigated in this study. The chromosomal inactivation of either lasI or lasR by recombination increased the production of both pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA) by 4-5 fold and 2-3 fold over that of the wild type strain of M18, respectively. Production of both antibiotics was restored to wild-type levels after in trans complementation with the wild-type lasI or lasR gene. Expression of the translational fusions pltA'-'lacZ and phzA'-'lacZ further confirmed the negative effect of lasI or lasR on both biosynthetic operons, and it was also demonstrated that the las system was related to the ability of swarming motility and the inhibition of cell growth.

H-NS family protein MvaU downregulates phenazine-1-carboxylic acid(PCA)biosynthesis via binding to an AT-rich region within the promoter of the phz2 gene cluster in the rhizobacterium Pseudomonas strain PA1201

Histone-like nucleoid-structuring(H-NS)proteins are key regulators in gene expression silencing and in nucleoid compaction.The H-NS family member proteins MvaU in Pseudomonas aeruginosa are thought to bind the same AT-rich regions of chromosomes and function to coordinate the control of a common set of genes.Here,we explored the molecular mechanism by which MvaU controls PCA biosynthesis in P.aeruginosa PA1201.We present evidence suggesting that MvaU is self-regulated.Deletion of mvaU significantly increased PCA production,and PCA production sharply decreased when mvaU was over-expressed.MvaU transcriptionally repressed phz2 cluster expression and consequently reduced PCA biosynthesis.β-galactosidase assays confirmed that base pairing near the35 box is required when MvaU regulates PCA production in PA1201.Electrophoretic mobility shift assays(EMSA)and additional point mutation analysis demonstrated that MvaU directly bound to an AT-rich motif within the promoter of the phz2 cluster.Chromatin immunoprecipitation(ChIP)analysis also indicated that MvaU directly bound to the P5 region of the phz2 cluster promoter.MvaU repression of PCA biosynthesis was independent of QscR and OxyR in PA1201 and neither PCA or H2O2 were the environmental signals that induced mvaU expression.These findings detail a new MvaU-dependent regulatory pathway of PCA biosynthesis in PA1201 and provide a foundation to increase PCA fermentation titer by genetic engineering.

Relationships of Ethylene Evolution Rate and 1-Aminocylopropane-1-Carboxylic Acid Concentration in Grains during Filling Period with Appearance Quality of Rice

To elucidate the relationship between ethylene evolution from the grains and the appearance quality of rice, ten different rice genotypes were used to determine the ethylene evolution rate, 1-aminocylopropane-1-carboxylic acid （ACC） concentration in grains during grain filling and the appearance quality of rice, and the effects of chemical regulators on concentrations of ethylene and ACC in the grains during grain filling were also investigated to verify the roles of ethylene in the rice quality formation. The ethylene evolution rates and ACC concentrations in grains during the mid and late grain filling stages were very significantly and positively correlated with chalky kernel percentage and chalkiness. The cultivars with a low ACC concentration in grains exhibited a close amyloplast arrangement and small space between starch granules, whereas those with a high ACC concentration in grains showed a loose arrangement and wide space between the granules. Application of 1 μmol/L ACC to panicles at mid and late grain filling stages significantly loosened amyloplast arrangement and increased chalky kernel percentage, chalky area and chalkiness, and the results were reversed when 1 μmol/L amino-ethoxyvinylglycine, an inhibitor of ACC synthesis enzyme, was applied to panicles. A practice of moderate dry-wet alternate irrigation reduced ethylene evolution and ACC concentration in grains and thereby reduced chalkiness. The results suggested that ethylene and ACC in grains play an important role in the endosperm structure and appearance quality of rice, and the appearance quality would be improved by reducing ethylene evolution and ACC in grains through either variety breeding and selection, or chemical regulations or cultivation techniques.

Synthesis and Crystal Structure of 1-H-Pyrrole-2-carboxylic Acid [2-(Naphthalen-1-ylamino)-ethyl]-amide

1-H-Pyrrole-2-carboxylic acid [2-（naphthalen-1-ylamino）-ethyl]-amide has been synthesized and characterized. Its crystal is of monoclinic, space group P2 1/n with a = 5.930（6）, b = 12.144（13）, c = 20.10（2） , A, β = 95.709（17）°, V= 1441（3） ,A, Z= 4, C17H17N3O, Mr= 279.34, Dc= 1.288 g/cm^3, F（000） = 592, μ（MoKa） = 0.083 mm^-1, S = 1.019, R = 0.0473 and wR = 0.1181 for 1713 observed reflections with I 〉 2 σ（I）. X-ray diffraction reveals that two molecules of the title compound form a dimer through a pair of N-H…O hydrogen bonds.

3,6-dichlorobenzo[b]thiophene-2-carboxylic acid alleviates ulcerative colitis by suppressing mammalian target of rapamycin complex 1 activation and regulating intestinal microbiota

BACKGROUND 3,6-dichlorobenzo[b]thiophene-2-carboxylic acid(BT2)is a benzothiophene carboxylate derivative that can suppress the catabolism of branched-chain amino acid(BCAA)-associated mammalian target of rapamycin complex 1(mTORC1)activation.Previous studies have demonstrated the therapeutic effects of BT2 on arthritis,liver cancer,and kidney injury.However,the effects of BT2 on ulcerative colitis(UC)are unknown.AIM To investigate the anti-UC effects of BT2 and the underlying mechanism.METHODS Mouse UC models were created through the administration of 3.5%dextran sodium sulfate(DSS)for 7 d.The mice in the treated groups were administered salazosulfapyridine(300 mg/kg)or BT2(20 mg/kg)orally from day 1 to day 7.At the end of the study,all of the mice were sacrificed,and colon tissues were removed for hematoxylin and eosin staining,immunoblot analyses,and immunohistochemical assays.Cytokine levels were measured by flow cytometry.The contents of BCAAs including valine,leucine,and isoleucine,in mouse serum were detected by liquid chromatography-tandem mass spectrometry,and the abundance of intestinal flora was analyzed by 16S ribosomal DNA sequencing.RESULTS Our results revealed that BT2 significantly ameliorated the inflammatory symptoms and pathological damage induced by DSS in mice.BT2 also reduced the production of the proinflammatory cytokines interleukin 6(IL-6),IL-9,and IL-2 and increased the anti-inflammatory cytokine IL-10 level.In addition,BT2 notably improved BCAA catabolism and suppressed mTORC1 activation and cyclooxygenase-2 expression in the colon tissues of UC mice.Furthermore,highthroughput sequencing revealed that BT2 restored the gut microbial abundance and diversity in mice with colitis.Compared with the DSS group,BT2 treatment increased the ratio of Firmicutes to Bacteroidetes and decreased the abundance of Enterobacteriaceae and Escherichia-Shigella.CONCLUSION Our results indicated that BT2 significantly ameliorated DSS-induced UC and that the latent mechanism involved the suppression of BCAA-associated mTORC1 activation and modulation of the intestinal flora.

Plant Growth Promoting Rhizobacteria Having 1-Aminocyclopropane-1-Carboxylic Acid Deaminase to Induce Salt Tolerance in Sunflower (<i>Helianthus annus L.</i>)

Soil salinity badly affects agriculture productivity through accumulation of salts in upper layers of soils. The harmful effects of salts in arable lands have influenced modern as well as ancient civilizations. A pot study was carried out to test the performance of two PGPR isolates (KS 8, KS 28) on sunflower (SMH-0917) under different salinity levels (8, 10 and 12 dS·m-1). These salinity levels were developed by adding calculated amount of salts (NaCl, Na2SO4, CaCl2 and MgSO4) with ratio of 3:4:2:1. The bacterial strains KS 8 and KS 28 were applied separately in two treatments while third treatment was co-inoculation (KS mix). Completely randomized experimental design (CRD) was used and data were collected at flowering stage about pre-decided plant growth parameters (plant height, shoot dry weight and root dry weight). The bacterial isolate KS 8 showed an increase of 26, 102% and 83% in plant height, shoot dry weight and root dry weight at EC 8 dS·m-1, while this improvement was 67%, 163% and 296% at EC 10 dS·m-1, however an increase of 100%, 74% and 382% was recorded over control respectively at EC 12 dS·m-1. Similarly isolate KS 28 exhibited an increase of 14%, 69% and 54% in plant height;shoot dry weight and root dry weight at EC 8 dS·m-1, whereas this improvement was 56%, 163% and 188% at EC 10 dS·m-1, while an increase of 60%, 41% and 282% was registered respectively over control at EC 12 dS·m-1. The increase due to mixture treatments was 4%, 41% and 16% in plant height, shoot dry weight and root dry weight at EC 8 dS·m-1, while an increase of 33%, 57% and 100% at EC 10 dS·m-1, whereas an improvement of 53%, 33% and 164% respectively was noted at EC 12 dS·m-1 over un-inoculated. The isolate KS 8 performed better than KS 28 and mixture treatment. These two PGPR strains could be used to mitigate the adverse impact caused by salinity stress on sunflower.

Synthesis and in vitro-Anti-hepatitis B Virus Activities of Several Ethyl 5-Hydroxy-1H-indole-3-carboxylates

A series of ethyl 5-hydroxyindole-3-earboxylates 6a-10r was designed and synthesized. The structures of all the compounds were confirmed by IR, ^1H NMR, and MS and their anti-hepatitis B virus （HBV） activities were evaluated in 2.2.15 cells. Among them, compound 7g { ethyl 5-hydroxy-2- [ （ 3-methoxyphenylsulfinyl ） methyl ] -1-methyl-4- [ （4-methylpiperazin-1-yl） methyl ]-1H-indole-3-carboxylate} displays a significant anti-HBV activity, which is more potent than the positive control lamivudine.

Synthesis and Crystal Structure of a Novel Ethyl 5-(4-(2-Phenylacetamido)phenyl)-1H-pyrazole-3-carboxylate as an Acrosin Inhibitor

The title compound （ethyl5-（4-（2-phenylacetamido）phenyl）-lH-pyrazole-3-carboxylate, C20H19N3O3） was synthesized by the reaction of Claisen condensation, cyclization, reduction and acylation. The structure was characterized by X-ray diffraction, MS, NMR and IR. It belongs to the monoclinic system, space group C2/c with a = 22.723（9）, b = 9.324（4）, c = 18.890（8） A, β = 114.259（6）°, V = 3649（3） A^3, Dc = 1.272 Mg·m^3, Z = 8, Mr = 349.38, p = 0.087 mm^-1, F（000） = 1472, the final R = 0.0615 and wR = 0.1643. The biological test shows that the title compound has a moderate acrosin inhibition activity.

Syntheses and Characterization of Two New Alkaline Earth Metal-organic Topological Frameworks with 3-Amino-1H-1,2,4-triazole-5-carboxylate

Two new alkaline earth metal coordination polymers constructed from the deriva-tive of 1,2,4-triazole are presented herein,namely,{[Sr（AmTAZAc）2（H2O）]}（1） and {[Ba（AmTAZAc）2（H2O）]}（2）（AmTAZAc = 3-amino-1H-1,2,4-triazole-5-carboxylate）,which have been synthesized by using the layering method and structurally characterized by elemental analysis,IR,and single-crystal X-ray diffraction.Complexes 1 and 2 are isostructural,and both crystallize in the orthorhombic system,space group Fdd2.X-ray structural analysis shows that 1 or 2 has an intriguing 3-D infinite network of（318.438.510） topology based on a 2-D sheet structure of（4,4） net.The result shows that noncovalent interactions play an important role in strengthening the whole structures of the compounds.

Synthesis and in vitro Anti-hepatitis B Virus Activity of Some Ethyl 5-Hydroxy-4-substituted Aminomethyl-2-sulfinylmethyl-1H-indole-3-carboxylates

A novel series of ethyl 5-hydroxy-4-substituted aminomethyl-2-sulfinylmethyl-lH-indole-3-carboxylates 8a--8j and 11e--11f was synthesized and evaluated in HepG2.2.15 cells for their anti-hepatitits B virus（HBV） activity and cytotoxicity. Among them, six compounds showed more potent inhibitory activity than lamivudine. Compound 8e exhibited the most significant anti-HBV activity with an IC50 value of 1.62 μmol/L, which was 33-times more potent than the reference drug lamivudine（IC50=54.78μmol/L）.

Green Chemistry Approach to Fast and Highly Efficient One-Pot Synthesis of Bis-Isoxazolyl-1,2,5,6-Tetrahydro Pyridine-3-Carboxylates

The synthesis of the bis-isoxazolyl-1,2,5,6-tetrahydro pyridine-3-carboxylates is achieved in high yield without the production of toxic waste products by using room temperature ionic liquid (RTILs) triethyl ammonium acetate (TEAA). The RTIL TEAA played the dual role of efficient green solvent as well as recyclable catalyst.

Synthesis and Crystal Structure of Methyl 2-(Diphenylamino)-4-phenyl-1,3-thiazole-5-carboxylate

The title compound, methyl 2-（diphenylamino）-4-phenyl-1,3-thiazole-5-carboxylate, was synthesized and studied by single-crystal X-ray diffraction method. The structure of the product was confirmed by IR, 1H- and 13C-NMR spectroscopy and elemental analysis. These experimental studies were supported by quantum mechanical calculations. The structure was solved in monoclinic, space group P21/c with a = 9.573（3）, b = 19.533（7）, c = 9.876（3）, β = 92.35（4）°, V = 1845.2（10）3, T = 85（2） K, Z = 4, R = 0.040 and wR = 0.089 for 6424 observed reflections with I2σ（I）.

Isolation and identifi cation of antimicrobial metabolites from sea anemone-derived fungus Emericella sp.SMA01

Marine symbiotic fungi represent an intriguing source of discovery of novel secondary metabolites with various biological activities.Sea anemones are benthic marine invertebrates,however,the cultivable symbiotic fungi residing in the sea anemones are paid few attentions compared to those derived from their cnidarian counterparts.Here we show the identification of antimicrobial secondary metabolites from the sea anemone-derived symbiotic fungi.Out offive isolated fungal strains,only the strain SMA01 showed strong antimicrobial activities,which was assigned into the genus Emericella based on the morphological characteristics and the ITS sequencing.Media swift from liquid fermentation to solid rice medium presented little influence on its antibacterial activity.A chemical investigation of the ethyl acetate extract of the Emericella sp.SMA01 led to discovery of the primary antibiotic metabolite phenazine-1-carboxylic acid.The IC_(50) values of the phenazine-1-carboxylic acid against Phytophthora capsici,Gibberella zeae,and Verticillium dahliae were determined to be 23.26-53.89μg/mL.To the best of our knowledge,this was the first report of Emericella sp.in sea anemones.The current study may benefit understanding of the defensive chemical interactions between the symbiotic fungi and their host sea anemones.

Hydrothermal Synthesis and Crystal Structure of One Novel 1-D Copper(Ⅱ)-organic Framework:{[Cu_2(PP)_2(CBPC)]_2·7H_2O}_n

One novel 1-D copper（Ⅱ）-organic compound,namely {[Cu2（PP）2（CBPC）]2·7H2O}n（1,H2CBPC=1-[（2＇-carboxybiphenyl-4-yl）methyl]-2-propylimidazole-4-carboxylic acid,HPP=3-（2-pyridyl）pyrazole）,was synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that the two Cu（Ⅱ） ions in the distorted dimer [Cu2（PP）2] of 1 are linked by the carboxylate oxygen atoms on the phenyl and imidazole rings,respectively,forming one interesting snake-like chain.Single-crystal X-ray analyses reveal that it crystallizes in monoclinic,space group C2/c with a=30.656（8）,b=12.715（3）,c=22.405（5）,β=122.758（3）°,V=7344（3）3,Z=4,Mr=1681.65,Dc=1.521 g/cm3,F（000）=3464,μ=1.221 mm-1,the final R=0.0453 and wR=0.1023 for 4617 observed reflections with Ⅰ 〉2σ（Ⅰ）.

Synthesis, Reactions and Characterization of 1,1’-(1,4-Phenylenebis(3-amino-6-methyl-1H-pyrazolo[3,4-b]pyridine-4,5-diyl))bis(ethan-1-one)

Reaction of 4,4’-(1,4-phenylene)bis(5-acetyl-6-methyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile) (1) with methyl iodide afforded the 4,4’-(1,4-phenylene)bis(5-acetyl-6-methyl-2-(methylthio)nicotinonitrile) (2). The reaction of 2 with hydrazine hydrate followed by diazotization reaction af-forded the 1,1’-(1,4-phenylenebis(3-amino-6-methyl-1H-pyrazolo[3,4-b]pyridine-4,5-diyl))bis(e-than-1-one) (3) and 1,1’-(1,4-phenylenebis(3-(chlorodiazenyl)-6-methyl-1H-pyrazolo[3,4-b]-pyridine-4,5-diyl))bis(ethan-1-one) (4) respectively. On the other hand, reaction of 4 with malononitrile, 2-cyanoethanethioamide, ethyl acetoacetate, acetyl acetone, ethyl benzoylacetate, diethylmalonate, ethyl cyanoacetate and phenacylbromide aiming to build up pyrazolotriazine or pyrazole ring on the ring system of 4. Structures of all newly synthesized heterocyclic compounds in the present study were confirmed by considering the data of IR, 1H NMR, mass spectra as well as that of elemental analyses.

A Practical Synthesis of 1-Oxo-1,2,3,4-tetrahydroisoquinoline-3-carboxylic Acid Esters

A practical synthetic method for methyl 1-oxo-1,2,3,4-tetrahydroisoquinoline-3-carboxylate was developed by means of triphosgene. Several analogues were prepared by this new method.

Three component reactions: An efficient and green synthesis of 3, 4-dihydropyrimidin-2-(1H)-ones and thiones using silica gel-supported L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate

An environmentally benign aqueous protocol for the synthesis of 3,4-dihydropyrimidin-2-（ 1 H）-ones and thiones promoted by a green catalyst, silica gel-supported L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate, has been developed. The use of nontoxic, thermally stable and inexpensive amino acid catalyst makes the process simple with minimal amount of chemical waste. Compared with classical Biginelli reaction conditions, this new method has the advantages of high yields and simple workup procedures.

Drug discovery based on the structure of FKBP12: Design, synthesis and evaluation of L-1,4-thiazane-3-carboxylic acid derivatives as neuroimmunophilin ligands

By choosing neuroimmunophilin FKBP12 as a therapeutical target, we have attempted to discover a new structural drug for treating neurodegenerative disease. This drug should possess neurotrophic activity and not affect the immune system. Based on the crystal structure of FKBP12, FK506 and Calcineurin complex, a series of small organic molecules were designed. These molecules were to have the ability of binding to FKBP12 in a virtual screening. By using a solution parallel synthetic method, these compounds were synthesized. The neuroprotective and neuroregenerative activities of these compounds were evaluated by binding assays, PC12 cells survival and neurite outgrowth model, chick dorsal root ganglion cultures (DRG) and 6-OHDA lesioned mice sympathetic nerve endings model. The evaluation results of these compounds showed that compound N308 has great promise as a candidate for a neuroprotective and neuroregenerative agent.

Three Zinc(Ⅱ) Complexes Based on 2-Carboxylic Acid-4-nitropyridine-1-oxide: Synthesis, Crystal Structure, and Fluorescence Properties

Three new metal-organic complexes, namely [Zn(POA)2(H2O)2](1), [Zn(POA)2(H2O)2]·2H2O(2) and [Zn(POA)2]n(3), have been synthesized by organic ligand 2-carboxylic acid-4-nitropyridine-1-oxide(POA) and zinc(Ⅱ) ions. The structures of complexes 1~3 are characterized by single-crystal X-ray analysis, XRD powder diffraction analysis, infrared spectroscopy and thermal stability analysis method. Complex 1 belongs to monoclinic system, space group C2/c with a = 22.8215(15), b = 7.5613(16), c = 10.048(3) ?, β = 109.47°, V = 1634.7(6) ?~3, Z = 4, F(000) = 944, Dc = 1.900 g/cm^3, C(12)H(10)N4O(12)Zn, Mr = 467.61 and μ = 1.584 mm^(-1). The whole molecule presents "V" shape. Complex 2 is a centrosymmetric structure in triclinic system with space group P1: a = 7.4728(5), b = 7.6825(6), c = 8.5184(6) ?, α = 65.975(2), β = 79.87(2), γ = 89.855(2)°, V = 4384.1(5) ?~3, Z = 1, F(000) = 256, Dc = 1.908 g/cm^3, C(12)H(14)N4O(14)Zn, Mr = 503.64 and μ = 1.492 mm^(-1). Complex 3 is a one-dimensional chain structure belonging to monoclinic system and space group P21/c with a = 4.9456(6), b = 12.5322(14), c = 11.2514(13) ?, β = 97.313(11)°, V = 6916.8(14) ?~3, Z = 2, F(000) = 432, Dc = 2.072 g/cm^3, C(12)H6N4O(10)Zn, Mr = 431.58, and μ = 1.852 mm^(-1). In three complexes, six oxygen atoms from the surrounding coordination atoms form a ZnO6 distorted octahedral coordination geometry around the zinc ions. Meanwhile, fluorescent properties of the three complexes were investigated at room temperature. The fluorescence spectroscopic analysis demonstrated that the ligand POA shows red-shift after coordinating with the zinc(Ⅱ) ions.