P450ome of the white rot fungus Phanerochaete chrysosporium: structure, evolution and regulation of expression of genomic P450 clusters

The model white rot fungus Phanerochaete chrysosporium has the extraordinary ability to degrade (to CO2) lignin and detoxify a variety of chemical pollutants. Whole genome sequencing of this fungus has revealed the presence of the largest P450ome in fungi comprising approx. 150 P450 genes, most of which have unknown function. On the basis of our genome-wide structural and evolutionary analysis, these P450 genes could be classified into 12 families and 23 subfamilies and under 11 fungal P450 clans. The analysis further revealed an extensive gene clustering with a total of 16 P450 clusters constituted of up to 11 members per cluster. In particular, evidence and role of gene duplications and horizontal gene transfer in the evolution of these P450 clusters have been discussed using two of the P450 families [CYP63 and CYP505 (where CYP is cytochrome P450)] as examples. In addition, the observed differential transcriptional induction of the clustered members of the CYP63 gene family, in response to different xenobiotic chemicals and carbon sources, indicated functional divergence within the P450 clusters, of this basidiomycete fungus.

Microarray-based global differential expression profiling of P450 monooxygenases and regulatory proteins for signal transduction pathways in the white rot fungus Phanerochaete chrysosporium

Whole genome sequencing of the model white rot basidiomycete Phanerochaete chrysosporium has revealed the largest P450 contingent known to date in fungi, along with related phase I and phase II metabolic genes and signaling cascade genes. As a part of their functional characterization, genome-wide expression profiling under physiologically distinct conditions, nutrient-limited (ligninolytic) and nutrient-rich (non-ligninolytic), was investigated using a custom-designed 70-mer oligonucleotide microarray developed based on 190 target genes and 23 control genes. All 150 P450 genes were found to be expressible under the test conditions, with 27 genes showing differential expression based on a >twofold arbitrary cut-off limit. Of these, 23 P450 genes were upregulated (twofold to ninefold) in defined high-nitrogen cultures whereas four genes were upregulated (twofold to twentyfold) in defined low-nitrogen cultures. Furthermore, tandem P450 member genes in ten of the 16 P450 genomic clusters showed nonassortative regulation of expression reflecting their functional diversity. Full-length cDNAs for two of the high-nitrogen upregulated genes pc-hn1 (CYP5035A1) and pc-hn2 (CYP5036A1) and partial cDNA for a low-nitrogen upregulated gene pc-ln1 (CYP5037A1) were cloned and characterized. The study provided first molecular evidence for the presence of active components of the cAMP- and MAP kinase-signaling pathways in a white rot fungus; four of these components (cpka and ste-12 of cAMP pathway and two MAP kinases, mps1 and sps1) were significantly upregulated (fourfold to eightfold) under nutrient-limited conditions, implying their likely role in the regulation of gene expression involved in secondary metabolism and biodegradation processes under these conditions.

Anti-tubercular agents. Part 3. Benzothiadiazine as a novel scaffold for anti-Mycobacterium activity

In an effort to develop new and more effective therapies to treat tuberculosis, a series of benzothiadiazine 1,1-dioxide derivatives were synthesized and their in vitro activity against Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium intracellulare was evaluated. One of the compounds, 8c, exhibited potent anti-tubercular activity, particularly for the resistant strains and thus prompted us to investigate its in vivo profile. However, the in vivo testing in a mouse model of tuberculosis infection did not show significant anti-tubercular activity, probably because of its poor bioavailability.

Antitubercular agents. Part 2: New thiolactomycin analogues active against Mycobacterium tuberculosis

Structurally modified analogues of naturally occurring antibiotic thiolactomycin, substituted at 4-position of the thiolactone ring have been prepared and evaluated for their antitubercular activity. Some of the compounds have exhibited potential activity against Mycobacterium tuberculosis.

Antitubercular agents. Part 1: Synthesis of phthalimido- and naphthalimido-linked phenazines as new prototype antitubercular agents

The preparation and antitubercular properties of a series of phthalimido- and naphthalimido-linked phenazines are described. Some of these new compounds inhibited the growth of Mycobacterium tuberculosis ATCC 27294, Mycobacterium avium ATCC 49601, Mycobacterium intracellulare ATCC 13950 and some clinical isolates.

First example of ring expansion of activated quinolines and isoquinolines: novel benzoazepinesElectronic supplementary information (ESI) available: experimental section. See http://www.rsc.org/suppdata/cc/b4/b405100a/

Activated quinoline and isoquinoline undergo unexpected ring expansion by diazocarbonyl compounds via C-C insertion in the presence of 5 mol% of copper triflate to produce ethyl 1H-benzo[b]azepine-1-carboxylate and ethyl 3H-benzo[d]azepine-3-carboxylate, respectively, in excellent yields with a high degree of selectivity

Green protocol for conjugate addition of thiols to alpha,beta-unsaturated ketones using a [bmim]PF6/H2O system

Alpha,beta-unsaturated ketones undergo conjugate addition rapidly with thiols in a hydrophobic ionic liquid [bmim]PF(6)/H(2)O solvent system (2:1) in the absence of any acid catalyst to afford the corresponding Michael adducts in high to quantitative yields with excellent 1,4-selectivity under mild and neutral conditions. The enones show enhanced reactivity in ionic liquids, thereby reducing reaction times and improving the yields significantly. The use of ionic liquids helps to avoid the use of either acid or base catalysts for this conversion. The recovered ionic liquid was reused four to five times with consistent activity.

[Bmim]PF(6): a novel and recyclable ionic liquid for conversion of oxiranes to thiiranes in aqueous media

A variety of epoxides respond rapidly with potassium thiocyanate in [bmim]PF(6)-H(2)O (2:1) solvent system at room temperature under mild and convenient conditions to produce the corresponding thiiranes in high to quantitative yields. Enhanced rates, improved yields, and recyclability of ionic liquids are the remarkable features observed in ionic liquids (ILs). The use of ionic liquids for this transformation avoids the use of heavy metal halides as promoters and chlorinated hydrocarbons as solvents. The ionic liquid was recycled in five to six subsequent runs with gradual decrease in activity.

Solid-phase synthesis of isoxazolines

The polymer-supported synthesis of isoxazolines is described via nitrile oxide intermediates, starting from primary nitroalkanes in a one-pot process.

Optimization of fermentation conditions for production of glycopeptide antibiotic vancomycin by Amycolatopsis orientalis

Glycopeptides produced by Streptomyces species are the drugs used against beta-lactam drug-resistant staphylococcal infections, and vancomycin is important among them. Increased prevalence of resistant strains increased the usage of vancomycin worldwide and also promoted attempts for indigenous production. The optimum process conditions pH, temperature, inoculum size, agitation, and aeration for vancomycin production by Amycolatopsis orientalis were evaluated, statistically analyzed, and the response surface curves were constructed. The optimum process conditions were a pH of 7.6, a temperature of 29 degrees C, an inoculum size of 4.5%, an agitation of 255 rpm, and an aeration of less than 1:10 medium-to-air ratio.

Biotransformation of linear alkylbenzene sulfonate (LAS) by Phanerochaete chrysosporium: oxidation of alkyl side-chain

The white rot fungus Phanerochaete chrysosporium, which generally mineralizes substituted aromatics to CO2, transformed linear alkylbenzene sulfonate (LAS) surfactants mainly at their alkyl side chain. Degradation of LAS was evidenced by a zone of clearing on LAS-containing agar plates and colorimetric analysis of liquid cultures. Disappearance of LAS was virtually complete within 10 days in low nitrogen (2.4 mM N), high nitrogen (24 mM N) and malt extract (ME) liquid media. After 5 days of incubation in ME medium, transformation of LAS was complete at concentrations < or = 4 mg l(-1), but decreased at higher concentrations. The LAS degradation was not dependent on lignin peroxidases (LiPs) and manganese-dependent peroxidases (MnPs). Mineralization of 14C-ring-LAS to 14CO2 by P. chrysosporium was < 1% regardless of the culture conditions used. Thin layer chromatography and mass spectral analyses indicated that P. chrysosporium transformed LAS to sulfophenyl carboxylates (SPCs) through oxidative shortening of the alkyl side-chains. While LAS disappearance in the cultures was not dependent on LiPs and MnPs, transformation of the parent LAS moieties to SPCs was more extensive in low N medium that favors expression of these enzymes. The SPCs produced in LN cultures were shorter in chain- length than those produced in ME cultures. Also there was a notable shift in the relative abundance of odd and even chain length metabolites compared to the starting LAS particularly in the low N cultures suggesting the possible involvement of processes other than or in addition to beta-oxidation in the chain-shortening process.

Efficient enantioselective reduction of ketones with Daucus carota root

A novel and efficient reduction of various prochiral ketones such as acetopehones, alpha-azido aryl ketones, beta-ketoesters, and aliphatic acyclic and cyclic ketones to the corresponding optically acive secondary alcohols with moderate to excellent chemical yield was achieved by using Daucus carota, root plant cells under extremely mild and environmentally benign conditions in aqueous medium, has been described. Many of these optically active alcohols are the potential chiral building blocks for the synthesis of pharmaceutically important molecules and asymmetric chiral ligands. Hence, this biocatalytic approach is found to be the most suitable for the preparation of a wide range of chiral alcohols and gave inspiration for the development of a new biotechnological process.

Cerium(III) chloride promoted highly regioselective ring opening of epoxides and aziridines using NaN(3) in acetonitrile: a facile synthesis of 1,2-azidoalcohols and 1,2-azidoamines

A convenient and efficient synthesis of 1,2-azidoalcohols and 1,2-azidoamines has been achieved by ring opening of epoxides and aziridines using cerium(III) chloride and sodium azide in acetonitrile. The reaction is highly regioselective and afforded the corresponding products in good to excellent yields under mild and neutral reaction conditions. The method is very rapid and equally compatible for both epoxides and aziridines.