Benzene Ring Compounds Research Articles

Compound Bacillus improves eggshell quality and egg metabolites of hens by promoting the metabolism balance of calcium and phosphorus and uterine cell proliferation

Probiotics have beneficial effects on improving egg quality, but there is little research about the effect of probiotics on metabolite composition, and the mechanisms are not yet fully understood. The aim of this study was to investigate the potential mechanisms by which compound Bacillus improves egg quality and metabolite composition. A total of 20,000 Jingfen No. 6 laying hens at 381 d old were randomly divided into two treatments: control group with a basal diet, and the basal diet with compound Bacillus supplementation (Ba) group. The trial lasted eight weeks. The results showed that compound Bacillus improved the gloss and strength of eggshells and reduced the ratio of sand-shell eggs by 23.8%. Specifically, the effective layer of eggshell was thicker and its calcite column was closely connected. Compound Bacillus increased the contents of beneficial fatty acids in the egg yolk, and lipids and lipid-like molecules in the albumen (P < 0.01), while decreased the contents of total cholesterol, triglycerides, and benzene ring compounds in the egg yolk and organic oxygen compounds in the albumen (P < 0.01). In addition, the compound Bacillus increased the calcium absorption in the duodenum by up-regulating the expression of transporters and serum hormone synergism (P < 0.05), and promoted metabolic balance of calcium and phosphorus. Simultaneously, uterine transcriptome showed that the expression of ChaC glutathione specific gamma-glutamylcyclotransferase 1 (CHAC1), glycoprotein-N-acetylgalactosamine 3-beta-galactosyltransferase 1 (C1GALT1), phosphatidylinositol-4-phosphate 5-kinase type 1 beta (PIP5K1B), methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), brain enriched myelin associated protein 1 (BCAS1), and squalene epoxidase (SQLE) genes were increased (P < 0.01), indicating that nutrient metabolism activity was enhanced. The expression of the BCAS1, C1GALT1, KLF transcription factor 13 (KLF13), and leucine rich repeat neuronal 1 (LRRN1) was increased (P < 0.01), indicating that the cell proliferation was enhanced, which slowed uterus aging. In conclusion, compound Bacillus improved the eggshell strength and metabolite composition in the egg by promoting metabolic balance of calcium and phosphorus, cell proliferation, and nutrient metabolism in the uterus.

Structure-based design and synthesis of anti-fibrotic compounds derived from para-positioned 3,4,5-trisubstituted benzene

Liver fibrosis is an abnormal wound-healing response to liver injuries. It can lead to liver cirrhosis, and even liver cancer and liver failure. There is a lack of treatment for liver fibrosis and it is of great importance to develop anti-fibrotic drugs. A pivotal event in the process of developing liver fibrosis is the activation of hepatic stellate cells (HSCs), in which the nuclear receptor Nur77 plays a crucial role. This study aimed to develop novel anti-fibrotic agents with Nur77 as the drug target by modifying the structure of THPN, a Nur77-binding and anti-melanoma compound. Specifically, a series of para-positioned 3,4,5-trisubstituted benzene ring compounds with long-chain backbone were generated and tested for anti-fibrotic activity. Among these compounds, compound A8 was with the most potent and Nur77-dependent inhibitory activity against TGF-β1-induced activation of HSCs. In a crystal structure analysis, compound A8 bound Nur77 in a peg-in-hole mode as THPN did but adopted a different conformation that could interfere the Nur77 interaction with AKT, which was previous shown to be important for an anti-fibrotic activity. In a cell-based assay, compound A8 indeed impeded the interaction between Nur77 and AKT leading to the stabilization of Nur77 without the activation of AKT. In a mouse model, compound A8 effectively suppressed the activation of AKT signaling pathway and up-regulated the cellular level of Nur77 to attenuate the HSCs activation and ameliorate liver fibrosis with no significant toxic side effects. Collectively, this work demonstrated that Nur77-targeting compound A8 is a promising anti-fibrotic drug candidate.

Synergistic mechanism of Bacillus subtilis Czk1 combined with propiconazole and tebuconazole mixtures against Pyrrhoderma noxium

BackgroundBrown root rot disease is one of the devastating diseases in the rubber production process. It is not easy to be detected in the early stage of the disease. Our early research revealed that the rubber tree brown root rot fungus Pyrrhoderma noxium Pn006 was effectively inhibited by Bacillus subtilis Czk1 and 25% propiconazole–tebuconazole, and that the two agents might work in synergy. Therefore, in this investigation, we used non-targeted metabolomic method to evaluate the synergistic mechanism of B. subtilis Czk1 and 25% propiconazole–tebuconazole on Pyrrhoderma noxium Pn006.ResultsMetabolomics analysis identified 708 unique metabolic markers, including mainly lipids and lipid-like molecules, organic acids, alcohols, ketones, alkaloids and their derivatives, nucleotides and their analogues, benzene ring compounds and amino acids and their derivatives. Further screening identified 105 key metabolic markers that could be potential biomarkers to reveal the mechanism of biocontrol bacteria and chemical fungicides combination synergy. Three key metabolic pathways were found in pathway enrichment, including linolenic acid metabolism, benzoic acid degradation, and valine, leucine and isoleucine degradation.ConclusionsThe mechanism might be related to the influence of the energy supply and cell functional integrity of pathogenic fungal cells.Critical relevance statement A metabolomic method was utilized to investigate the synergistic effects of B. subtilis Czk1 and 25% propiconazole–tebuconazole use on Pyrrhoderma noxium Pn006.Graphical

Effective and mechanistic insights into reverse osmosis concentrate of landfill leachate treatment using coagulation-catalytic ozonation-bioaugmentation-based AnMBR

Landfill leachate membrane concentrates containing high concentrations of organics pose a major threat to the environment, and efficient treatment methods are urgent issue. In this study, a coagulation-catalytic ozonation-bioaugmentation-based anaerobic membrane bioreactor (CCOB-AnMBR) process was applied to treat reverse osmosis concentrate (ROC) of landfill leachate. Compared with polyaluminum ferric chloride (PAFC) and prefrontal cortex (PFC), coagulation using polyferric sulfate (PFS) effectively removed refractory contaminants including macro molecular organics (MMOs), benzene ring compounds (BRCs), humic acid (HA), and fulvic acid (FvA) in ROC of landfill leachate, with average 78.3%, 53.5%, 34.7% and 34.3%, respectively. Catalytic ozonation with MnOx-CeOx-Al2O3 increased the biodegradability index by degrading refractory organic compounds, which facilitated subsequent biological treatment of ROC. The oxidation of mostly occurs at the solid–liquid interface and the presence of MnOx-CeOx-Al2O3 nanocatalyst enhanced ozone decay and increased generation of hydroxyl radical (•OH) and singlet oxygen (1O2) in ROC. In addition, bioaugmentation using recombinant genetically engineered Desulfovibrio vulgaris expressing Sat and dsrAB (rGEDEV-sds) promoted metabolism of sulfate by driving transfer sulfate from the environment into the cell and sulfate dissimilation reduction process. Bioaugmentation-based AnMBR (Bio-AnMBR) caused complete degradation of the total organic carbon (TOC), enhanced degradation of leachate pollutions, and decreased the concentration of sulfate in ROC. The macro molecular organics, refractory organic contaminants, the residual coagulation-resistant substances (CRS), and heavy metal were effectively degraded in the Bio-AnMBR system. Furthermore, CCOB-AnMBR exhibits high processing efficiency in the degradation of the contaminants in ROC of landfill leachate. Overall, this excellent performance proves the feasibility and elucidates the mechanism of CCOB-AnMBR process for the removal of contaminants in ROC of landfill leachate.

Treatment of nanofiltration concentrate of landfill leachate using advanced oxidation processes incorporated with bioaugmentation

Advanced oxidation processes have been broadly applied in wastewater treatment, but few studies have focused on its degradative effect on refractory organic contaminants in membrane concentrates of landfill leachate. In this study, the treatment effects of advanced oxidation processes including electrocoagulation (EC), ozone (OZ), anodic oxidation (AO) and electro-Fenton (EF) incorporated with genetically engineered nitrifying bacteria Rhodococcus erythropolis expressing Nirs and AMO (rRho-NM) on nanofiltration concentrate (NFC) of old landfill leachate were investigated in a lab-scale experiment. The results showed that advanced oxidation processes degraded the refractory organic contaminants including coagulation-resistant substances (CRS), humic acid (HA), fulvic acid (FvA), macro molecular organics (MMOs) and benzene ring compounds (BRCs) and increased the biodegradability in NFC of old landfill leachate. Compared to activated sludge (AS), rRho-NM exhibited an excellent removal performance for total organic carbon (TOC), ammonia nitrogen (NH4–N), total nitrogen (TN), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) for advanced oxidation processes-treated NFC of old landfill leachate. Advanced oxidation processes incorporated with bioaugmentation demonstrated an outstanding degradation performance for removing refractory organic contaminants, TOC, NH4–N, TN, BOD, COD and heavy metal in NFC of old landfill leachate. In addition, OZ incorporated with rRho-NM (OZ-rRho-NM) showed the optimal removal efficacy in reduction of refractory organic contaminants, TOC, NH4–N, TN, BOD and COD, the shortest hydraulic retention time (HRT) and the minimum energy consumption in NFC of landfill leachate. Furthermore, the cheapest treatment cost for NFC could be achieved by EC incorporated with rRho-NM (EC-rRho-NM). More impressively, rRho-NM remained stable in expressing Nirs and AMO genes, increased nitrification and denitrification rate, and improved MBR effluent quality in the treatment of NFC. In conclusion, this work provides new insights into the application of advanced oxidation processes incorporated with bioaugmentation using rRho-NM for the treatment of NFC of old landfill leachate.

Search for biologically active compounds in the series of indazole derivatives

Indazole compounds are intensively used in the synthesis of new active substances for pharmacological purposes. The present work includes methods of modification and preparation of new indazole compounds, determination of their biological activity (antibacterial properties, antiprotozoal and fungistatic activity). Modification methods were used: the recyclization reaction; acetylation of the amino group; acylation and others. We have synthesized indazole derivatives containing an aryl substituent with a 2-aminoethyl fragment by recyclization of 1-(2-chloroaryl)-3,4-dihydroioquinolines under the influence of hydrazine. The starting structures for the synthesis of indazoles (compounds 5, 6, 7) possess negligible activity toward Colpoda steinii, are practically inactive toward Penicillium italicum but retard the growth of E. coli and Staphylococcus aureus (retard zone 7-9 mm); compounds with dimethoxy groups in the benzene ring (compounds 5 and 6) are active toward E. coli whereas structure 7 has no activity without dimethoxy groups. The recycling reaction leading to indazole structures considerably increases the activity of all compounds (1-4, 8-14). Compounds with a primary amino group (structures 1, 2, and 9) possess marked antiprotozoan activity, the best results in this respect being demonstrated by compound 9 which does not contain dimethoxy groups in the benzene ring (15.6 ?g/ml). Acylation of the amino group in compound 2 allows a 4-fold increase in antiprotozoic activity and a slight fungistatic activity (compound 3). At the same time, acylation with a bulkier and more lipophilic benzoyl group (compound 4) practically suppresses antiprotozoic and fungistatic activities. It should be noted that conversion of the primary amino group of compounds 1 and 9 to the tertiary amino group (compounds 13 and 14) allows a dramatic increase in antiprotozoal activity (31.25 µg/ml for compound 1 and 3.9 µg/ml for compound 13; 15.6 µg/ml for compound 9 and 3.9 µg/ml for compound 14). In addition, these same compounds 13 and 14, unlike compounds 1 and 9, are active against all cultures studied. The best results are shown by compounds 11 and 12 in which the amino group is part of the urea structure.

Lignin-based sulfonated carbon as an efficient biomass catalyst for clean benzylation of benzene ring compounds

Low-temperature carbonization–sulfonation two-step process or one-step sulfonation process was employed to draft sodium lignosulfonate (SLS), the primary biological macromolecule ingredient of papermaking black liquor, into lignin-based sulfonated carbon. The two-step lignin-based sulfonated carbon named SLC400,1S was found to be an efficient catalyst for clean Benzyl-alcohol (BA) route Friedel-Crafts (F-C) benzylation of benzene ring compounds. FT-IR, XRD, Raman spectra, XPS, SEM with EDX-mapping, TGA-DSC, acid-base titration, and n-butylamine–acetonitrile titration characterizations demonstrated that the specific two-step process could introduce porous properties and a large number of surface sulfonic, hydroxyl, and carboxyl active groups into the structure of the prepared material, which was found to account for the good catalytic performance for benzylation. Similar to that of hierarchical mesoporous ZSM-5 under optimal conditions, the apparent activation energy for benzylation of paraxylene (PX) with BA over SLC400,1S was estimated to be 119 kJ·mol−1. The common by-product of BA route benzylation, dibenzyl ether (DBE), was almost inhibited because of the extraordinary activity of SLC400,1S and the optimized reaction conditions. A 12-run recycling test demonstrated easy recovery and steady reusability of the above lignin-based sulfonated carbon catalyst.

Oxidative status of planarians is differently affected by PAHs: 3-5 Benzene ring compounds

Planarians are promising model animals and are increasing in importance for ecotoxicological studies. However, there is scarce to no information regarding polycyclic aromatic hydrocarbons (PAHs) specific toxicity towards planarians at the biochemical level. We aimed to uncover how vital physiological functions, such as, neurophysiology, detoxification and oxidative stress status, and cellular energy allocation are affected on the freshwater planarian Girardia tigrina by low and high molecular weight PAHs – phenanthrene, pyrene and benzo[a]pyrene (B[a]P). Phenanthrene affected planarian antioxidant defences and detoxification, increasing glutathione levels and activity of glutathione-S-transferase (GST), the latter in a dose-dependent way (from 75 to 300 µg L−1). Phenanthrene also decreased carbohydrates in planarians exposed to 150 and 300 µg L−1. Pyrene caused higher oxygen consumption and decreased energy budget in planarians exposed to 75 and 150 µg L−1. B[a]P exposure decreased G. tigrina GST activity in a dose-dependent way. Lower lipid peroxidation levels were measured in planarians exposed to 2.5 and 75 µg L−1 of pyrene and at 37.5, 75 and 150 µg L−1 of B[a]P. The present data indicate that each of these PAHs seems to elicit distinct biochemical responses in planarians, possibly pointing to different biochemical interactions and/or metabolisation of each compound, with B[a]P causing the most severe effects.

Oxidative Status of Planarians is Differently Affected by PAHs: 3-5 Benzene Ring Compounds

Oxidative Status of Planarians is Differently Affected by PAHs: 3-5 Benzene Ring Compounds

Mechanism for degradation of dichlorodiphenyltrichloroethane by mechano-chemical ball milling with Fe-Zn bimetal

As a non-combustion technique for destruction of persistent organic pollutants, mechanochemical ball milling has attracted research attention worldwide due to high effectiveness, simplicity, and wide applicability. Previous studies have demonstrated that Fe-Zn bimetal outperformed other commonly used reagents such as CaO, Fe and Fe2O3 in mechanochemical destruction of industrial DDT. Mechanistic studies on mechanochemical destruction of persistent organic pollutants are rather limited and mechanisms may differ among reagents and chemicals. The objective of this study was to shed light on mechanisms for DDT destruction by Fe-Zn bimetal based mechanochemical treatment. A kinetics study showed that data for Fe-Zn treatment can be fitted to the Delogu model whereas that of CaO and Fe2O3 treatments followed a pseudo-second-order model. The identification of intermediates and characterization of the solid phase of the ground material revealed that dechlorination, dehydrochlorination, benzene-ring breaking, as well as splicing and condensation of small molecules occurred during the milling process. Cleavage and dehydrogenation eventually converted benzene-ring compounds into graphite and amorphous carbon.

Optimization of a pretreatment and hydrolysis process for the efficient recovery of recycled sugars and unknown compounds from agricultural sweet sorghum bagasse stem pith solid waste.

BackgroundSweet sorghum bagasse (SSB), comprising both a dermal layer and pith, is a solid waste generated by agricultural activities. Open burning was previously used to treat agricultural solid waste but is harmful to the environment and human health. Recent reports showed that certain techniques can convert this agricultural waste into valuable products. While SSB has been considered an attractive raw material for sugar extraction and the production of value-added products, the pith root in the SSB can be difficult to process. Therefore, it is necessary to pretreat bagasse before conventional hydrolysis.MethodsA thorough analysis and comparison of various pretreatment methods were conducted based on physicochemical and microscopic approaches. The responses of agricultural SSB stem pith with different particle sizes to pretreatment temperature, acid and alkali concentration and enzyme dosage were investigated to determine the optimal pretreatment. The integrated methods are beneficial to the utilization of carbohydrate-based and unknown compounds in agricultural solid waste.ResultsAcid (1.5−4.5%, v/v) and alkali (5−8%, w/v) reagents were used to collect cellulose from different meshes of pith at 25–100 °C. The results showed that the use of 100 mesh pith soaked in 8% (w/v) NaOH solution at 100 °C resulted in 32.47% ± 0.01% solid recovery. Follow-up fermentation with 3% (v/v) acid and 6.5% (w/v) alkali at 50 °C for enzymolysis was performed with the optimal enzyme ratio. An analysis of the surface topography and porosity before and after pretreatment showed that both the pore size of the pith and the amount of exposed cellulose increased as the mesh size increased. Interestingly, various compounds, including 42 compounds previously known to be present and 13 compounds not previously known to be present, were detected in the pretreatment liquid, while 10 types of monosaccharides, including D-glucose, D-xylose and D-arabinose, were found in the enzymatic solution. The total monosaccharide content of the pith was 149.48 ± 0.3 mg/g dry matter.DiscussionAn integrated technique for obtaining value-added products from sweet sorghum pith is presented in this work. Based on this technique, lignin and hemicellulose were effectively broken down, amorphous cellulose was obtained and all sugars in the sweet sorghum pith were hydrolysed into monosaccharides. A total of 42 compounds previously found in these materials, including alcohol, ester, acid, alkene, aldehyde ketone, alkene, phenolic and benzene ring compounds, were detected in the pretreatment pith. In addition, several compounds that had not been previously observed in these materials were found in the pretreatment solution. These findings will improve the transformation of lignocellulosic biomass into sugar to create a high-value-added coproduct during the integrated process and to maximize the potential utilization of agricultural waste in current biorefinery processing.

Transformation and degradation mechanism of landfill leachates in a combined process of SAARB and ozonation

Dissolved organic matter (DOM) in mature landfill leachate is significantly different from that in young landfill leachate; the composition of DOM greatly influences both biological treatment and advanced treatment processes. In the present study, the transformation and degradation mechanisms of landfill leachates in a combined semi-aerobic aged refuse biofilter (SAARB) and ozonation process was investigated using organic removal analysis, molecular weight distribution (MWD), 3D-EEM-PARAFAC analysis, UV–Vis spectroscopy, and linear regression. Results revealed that the DOM in mature landfill leachate contained a greater amount of aromatic substances and had higher molecular weight than DOM in young landfill leachate. After the SAARB process, humus contained in the SAARB was discharged with effluent from both mature and young landfill leachate. Due to the differences in composition and structure of organic matter, the COD removal efficiency (17.89%) of SAARB effluent from treating mature landfill leachate (mature SAARB effluent) was much lower than that (45.91%) of SAARB effluent from treating young landfill leachate (young SAARB effluent) under the same operational parameters of the ozonation process. As indicated by PARAFAC analysis, better chemical stability of DOM in mature SAARB effluent resulted in inferior ozone treatment efficiency. Furthermore, the hydrophobicity and the concentration of benzene ring compounds in the mature and young SAARB effluent were reduced significantly by the ozonation process. Therefore, great improvements in the biodegradability of SAARB effluents were achieved in the ozonation process. Overall, the results of this study provide suggestions and guidance for practical applications of these technologies.

Degradation of refractory organic contaminants in membrane concentrates from landfill leachate by a combined coagulation-ozonation process

Landfill leachate is a typical refractory wastewater for which research into rapid and efficient treatment methods has become very topical. In this study, a coagulation-ozonation process was developed to treat the concentrate arising from membrane treatment of landfill leachate. The effect of coagulant type and initial pH on treatment efficiencies was investigated. Results showed that many of organics were effectively removed in the coagulation process. Thereafter, ozone was applied to further treat the coagulation-resistant organic substances. Our results revealed that the degradation rate of these coagulation-resistant substances followed the trend (color number) CN > (light absorbance at 254 nm) UV254 > (chemical oxygen demand) COD, and the residual coagulation-resistant substances were oxidized rapidly in the ozone process. Ozone first destroyed the molecular structure of fulvic acid and the by-products generated, such as protein-like substances. In addition, the molecular weight, organic condensation degree, and concentration of benzene ring compounds were considerably decreased. Moreover, the macro molecular organics (i.e., humic acid and fulvic acid) within the size range 1–100 kDa were effectively degraded and partially transformed into bicarbonate. Overall, the combined coagulation-ozonation process reduced COD, UV254, and CN in the landfill leachate concentrate by 88.32%, 94.37%, and 98.83%, respectively, and thus the biodegradability of the treated leachate also was significantly improved. This excellent performance proved the feasibility of the combined coagulation-ozonation process for the removal of recalcitrant organic substances contained in landfill leachate concentrate, benefiting subsequent biological treatment.

Degradation of organic pollutants in near-neutral pH solution by Fe-C micro-electrolysis system

The degradation of organic pollutants in the simulated and realistic wastewaters was investigated by Fe-C micro-electrolysis system. Effects of initial pH, Fe/C mass ratio, gas bubbling type (air or N2) and the type of anions on degradation and mineralization of Sunset Yellow (SY) were studied. The degradation and mineralization efficiencies of 500mg·L−1 SY were approximately 99.0% and 77.5% after 90min treatment, when the initial pH, Fe/C ratio and air bubbling flow rate were 6.0, 1:1 and 45L·h−1, respectively. Besides, the type of anions had a significant influence on the Fe-C micro-electrolysis process. The results of kinetics study indicated that Fe-C micro-electrolysis process followed second-order-kinetics well. The degradation pathway and mechanism for SY were proposed based on FTIR and LC–MS analyses of treated wastewater. Additionally, the Fe-C micro-electrolysis process could dispose linear alkyl chain and benzene ring compounds efficiently under the optimal conditions, and the mineralization efficiencies were in the range of 94–96% and approximately 80%, respectively. The degradation feasibility of a realistic wastewater by the Fe-C micro-electrolysis system was investigated with landfill leachate. In conclusion, Fe-C micro-electrolysis system is an effective and promising technology for organic wastewater treatment in near-neutral pH condition.

Photodegradation of pyrene on Al2O3 surfaces: a detailed kinetic and product study.

In the current study, the photochemistry of pyrene on solid Al2O3 surface was studied under simulated atmospheric conditions (pressure, 1 atm; temperature, 293 K; photon flux, JNO2 = 0.002-0.012 s(-1)). Experiments were performed using synthetic air or N2 as bath gas to evaluate the impact of O2 to the reaction system. The rate of pyrene photodegradation followed first order kinetics and was enhanced in the presence of O2, kd(synthetic air) = 7.8 ± 0.78 × 10(-2) h(-1) and kd(N2) = 1.2 ± 0.12 × 10(-2) h(-1) respectively, due to the formation of the highly reactive O2(•-) and HO(•) radical species. In addition, kd was found to increase linearly with photon flux. A detailed product study was realized and for the first time the gas/solid phase products of pyrene oxidation were identified using off-line GC-MS and HPLC analysis. In the gas phase, acetone, benzene, and various benzene-ring compounds were determined. In the solid phase, more than 20 photoproducts were identified and their kinetics was followed. Simulation of the concentration profiles of 1- and 2-hydroxypyrene provided an estimation of their yields, 33% and 5.8%, respectively, with respect to consumed pyrene, and their degradation rates were extracted. Finally, the mechanism of heterogeneous photodegradation of pyrene is discussed.

Structure-based efforts to optimize a non-β-lactam inhibitor of AmpC β-lactamase

β-Lactams are the most widely prescribed class of antibiotics, yet their efficacy is threatened by expression of β-lactamase enzymes, which hydrolyze the defining lactam ring of these antibiotics. To overcome resistance due to β-lactamases, inhibitors that do not resemble β-lactams are needed. A novel, non-β-lactam inhibitor for the class C β-lactamase AmpC (3-[(4-chloroanilino)sulfonyl]thiophene-2-carboxylic acid; Ki 26μM) was previously identified. Based on this lead, a series of compounds with the potential to interact with residues at the edge of the active site were synthesized and tested for inhibition of AmpC. The length of the carbon chain spacer was extended by 1, 2, 3, and 4 carbons between the integral thiophene ring and the benzene ring (compounds 4, 5, 6, and 7). Compounds 4 and 6 showed minimal improvement over the lead compound (Ki 18 and 19μM, respectively), and compound 5 inhibited to the same extent as the lead. The X-ray crystal structures of AmpC in complexes with compounds 4, 5, and 6 were determined. The complexes provide insight into the structural reasons for the observed inhibition, and inform future optimization efforts in this series.

The roles of plant phenolics in defence and communication during Agrobacterium and Rhizobium infection.

Phenolics are aromatic benzene ring compounds with one or more hydroxyl groups produced by plants mainly for protection against stress. The functions of phenolic compounds in plant physiology and interactions with biotic and abiotic environments are difficult to overestimate. Phenolics play important roles in plant development, particularly in lignin and pigment biosynthesis. They also provide structural integrity and scaffolding support to plants. Importantly, phenolic phytoalexins, secreted by wounded or otherwise perturbed plants, repel or kill many microorganisms, and some pathogens can counteract or nullify these defences or even subvert them to their own advantage. In this review, we discuss the roles of phenolics in the interactions of plants with Agrobacterium and Rhizobium.

Synthesis and Biological Evaluation of 2-, 3-, and 4-Acylaminocinnamyl-Nhydroxyamides as Novel Synthetic HDAC Inhibitors

A new series of 2-, 3-, and 4-acylaminocinnamyl-N-hydroxyamides 1-3 have been prepared, and their anti-HDAC (against maize HD2, HD1-B, and HD1-A enzymes) activities have been assessed. Cinnamyl-hydroxyamides bearing acylamino substituents at the C2 position of the benzene ring (compounds 1a-g) showed very low HDAC inhibiting activities, with IC(50) values in the high micromolar range. By shifting the same acylamino groups from C2 to C3 (compounds 2a-g) as well as C4 (compounds 3a-f) position of the benzene ring, a number of highly potent HDAC inhibitors have been obtained. In the anti-HD2 assay 3c (IC(50) = 11 nM) was the most potent compound, being >11600-, 4.5-, and 10-fold more potent than sodium valproate, SAHA, and HC-toxin, respectively, and showing the same activity as trapoxin. HD1-B and HD1-A assays have been performed to screen the inhibitory action of 1-3 against mammalian class I (HD1-B) and class II (HD1-A) HDAC homologous enzymes. From the corresponding IC(50) data, a selectivity ratio has been calculated. In general, compounds 1-3 showed no or little selectivity towards the class II homologue HD1-A, the most selective being 2a with class II selectivity ratio = 4.3. About the inhibitory potency, the 4-(2-naphthoylamino)cinnamyl-N-hydroxyamide 3f showed the highest inhibiting effect against the two enzymes (IC(50-HD1-B) = 36 nM; IC(50-HD1-A) = 42 nM). Selected 2 and 3 compounds will be evaluated to determine their antiproliferative and cyto differentiating activities on HL-60 cells.

Handbook of basic tables for chemical analysis

Handbook of basic tables for chemical analysis

The dissociative recombination of hydrocarbon ions. III. Methyl-substituted benzene ring compounds

The recombination of electrons with cyclic ions produced via ion–molecule reactions between atomic precursor ions and methyl-substituted benzene ring compounds (toluene, ortho-, and para-xylene and mesitylene) has been studied at 300 K using a flowing afterglow Langmuir probe-mass spectrometer apparatus. Differing amounts of energy can be deposited into the daughter ions depending upon which atomic precursor is used. It has been found that same-mass daughter ions formed from different precursors displayed different recombination rate coefficients indicating that different isomeric forms were reacting. In particular, the benzene ring of the toluene cation expands to a seven-membered ring following isomerization to the cycloheptatriene form. H atom abstraction allows two different isomeric daughter ions to be formed that do not interconvert and that display different recombination rates. A similar behavior was observed for the xylenes and for mesitylene. All recombination rates lie in the range from 10−7 to 10−6 cm3 s−1 and display no apparent relation with size nor with the aromaticity of the ions.