TMC-264, a novel antiallergic heptaketide produced by the fungus Phoma sp. TC 1674

[structure: see text] TMC-264 (1), a novel tricyclic heptaketide with a unique chloro-1H-dibenzo[b,d]pyran-4,6-dione skeleton, was discovered from the fungus Phoma sp. TC 1674. The structure was elucidated on the basis of NMR analyses of normal abundance and biosynthetically (13)C-enriched TMC-264. TMC-264 showed potent inhibitory activity against tyrosine phosphorylation of STAT6.     

Xantholipin, a novel inhibitor of HSP47 gene expression produced by Streptomyces sp.

In the course of our screening program to identify inhibitors of HSP47 gene expression, we obtained a novel aromatic substance from Streptomyces sp. named Xantholipin. Its structure was determined based on physicochemical data of Xantholipin and its derivatives. The absolute configuration was also established by the modified Mosher's method.     

Nitration of 2'-deoxyguanosine by a NO/O2 gas mixture: identification and characterization of N2-nitro-2'-deoxyguanosine

[reaction: see text] A gas mixture of NO and O(2) was bubbled into 2'-deoxyguanosine solution at neutral pH and 37 degrees C. A novel nitrated nucleoside was generated in the reaction mixture in addition to 8-nitroguanine, 8-nitroxanthine, 2'-deoxyxanthosine, xanthine, and guanine. The novel nucleoside was identified as N(2)-nitro-2'-deoxyguanosine by spectrometric data.     

Katorazone,a new yellow pigment with a 2-azaquinone-phenylhydrazone structure produced by Streptomyces sp. IFM 11299

An unusual alkaloid with a 2-azaquinone-phenylhydrazone structure, katorazone (1), and other metabolites were isolated from the ethyl acetate extract of Streptomyces sp. IFM 11299. The chemical structure of katorazone (1) was elucidated by 1D and 2D NMR analyses together with HR-ESI mass spectrometry. Katorazone (1) showed a synergistic effect in combination with TRAIL and decreased the viability of human gastric adenocarcinoma (AGS) cells.     

肠杆菌Enterobacter sp. S8共代谢生物降解邻苯二甲酸二丁酯的特性研究

邻苯二甲酸二丁酯(DBP)是目前应用最为广泛的邻苯二甲酸酯之一,属于难降解有机污染物,具有较强的内分泌干扰性。本文以分离得到的DBP降解菌Enterobacter sp.S8为研究对象,系统考察了共代谢基质类型和共代谢反应条件对S8共代谢生物降解DBP的影响,同时对其反应动力学及酶的稳定性进行了研究。结果表明,在无共基质添加的条件下,S8对DBP的降解率仅为30.2%,而在温度为30℃、pH为7、甲醇投加量为20mg/L以及DBP初始浓度为300mg/L的优化共代谢降解条件下降解率达到最大,为75.6%;其中DBP初始浓度对共代谢降解效果影响最大。本文的结果为采用生物共代谢方式进行DBP污染环境的治理提供了依据。     

Biochemical Basis of Mercury Remediation and Bioaccumulation by Enterobacter sp. EMB21

The aims of this study were to isolate metal bioaccumulating bacterial strains and to study their applications in removal of environmental problematic heavy metals like mercury. Five bacterial strains belonging to genera Enterobacter, Bacillus, and Pseudomonas were isolated from oil-spilled soil. Among these, one of the strains Enterobacter sp. EMB21 showed mercury bioaccumulation inside the cells simultaneous to its bioremediation. The bioaccumulation of remediated mercury was confirmed by transmission electron microscopy and energy dispersive X-ray. The mercury-resistant loci in the Enterobacter sp. EMB21 cells were plasmid-mediated as confirmed by transformation of mercury-sensitive Escherichia coli DH5α by Enterobacter sp. EMB21 plasmid. Effect of different culture parameters viz-a-viz inoculum size, pH, carbon, and nitrogen source revealed that alkaline pH and presence of dextrose and yeast extract favored better remediation. The results indicated the usefulness of Enterobacter sp. EMB21 for the effective remediation of mercury in bioaccumulated form. The Enterobacter sp. EMB21 seems promising for heavy metal remediation wherein the remediated metal can be trapped inside the cells. The process can further be developed for the synthesis of valuable high-end functional alloy, nanoparticles, or metal conjugates from the metal being remediated.     

Lambertellols A and B, novel 3,4-dihydronaphthalen-1(2H)-ones with spiro-butenolide produced by Lambertella sp.1346

[structure: see text] Lambertella sp. 1346 was found to produce lambertellols A (1) and B (2) carrying a novel dihydronaphthalen-1(2H)-ones with spiro-1-furan-2(5'H)-one. The spiro-lactone ring moiety of both 1 and 2 were easily migrated to afford lambertellin, a known metabolite of Lambertella corni-maris. The absolute stereochemistry of these compounds was established on the basis of CD spectrum after chemical derivatization.     

Chaetominine, a cytotoxic alkaloid produced by endophytic Chaetomium sp. IFB-E015

Chaetominine (1), an alkaloidal metabolite with a new framework, was characterized from the solid-substrate culture of Chaetomium sp. IFB-E015, an endophytic fungus on the apparently healthy Adenophora axilliflora leaves. Its structure was determined by a combination of its spectral data and single-crystal X-ray diffraction analysis, with its absolute configuration elucidated by Marfey's method. Chaetominine was more cytotoxic than 5-fluorouracil against the human leukemia K562 and colon cancer SW1116 cell lines. [structure: see text]     

Citriperazines A-D produced by a marine algae-derived fungus Penicillium sp. KMM 4672

Abstract

Four new diketopiperazine alkaloids, citriperazines A-D were isolated from algae-derived Penicillium sp. KMM 4672. The structures of compounds 1–4 were determined using spectroscopic methods. The absolute configurations of compounds 1 and 4 were established by comparison of calculated and experimental ECD spectra. The cytotoxicity of compounds 1–4 against several human prostate cell lines was evaluated.     

Synthesis of 2'-N-methylamino-2'-deoxyguanosine and 2'-N,N-dimethylamino-2'-deoxyguanosine and their incorporation into RNA by phosphoramidite chemistry

The 2'-hydroxyl groups within RNA contribute in essential ways to RNA structure and function. Previously, we designed an atomic mutation cycle (AMC) that uses ribonucleoside analogues bearing different C-2'-substituents, including -OCH(3), -NH(2), -NHMe, and -NMe(2), to identify hydroxyl groups within RNA that donate functionally significant hydrogen bonds. To enable AMC analysis of the nucleophilic guanosine cofactor in the Tetrahymena ribozyme reaction and at other guanosines whose 2'-hydroxyl groups impart critical functional contributions, we describe here the syntheses of 2'-methylamino-2'-deoxyguanosine (G(NHMe)) and 2'-N,N-dimethylamino-2'-deoxyguanosine (G(NMe(2))) and their corresponding phosphoramidites. The key step in obtaining the nucleosides involved S(N)2 displacement of 2'-β-triflate from an appropriate guanosine derivative by methylamine or dimethylamine. We readily obtained the G(NMe(2)) phosphoramidite and incorporated it into RNA. However, the G(NHMe) phosphoramidite posed a significantly greater challenge due to lack of a suitable -2'-NHMe protecting group. After testing several strategies, we established that allyloxycarbonyl (Alloc) provided suitable protection for 2'-N-methylamino group during the phosphoramidite synthesis and the subsequent RNA synthesis. This work enables AMC analysis of guanosine's 2'-hydroxyl group within RNA.     

Argadin, a new chitinase inhibitor, produced by Clonostachys sp. FO-7314

A new chitinase inhibitor, designated as argadin (1), was isolated from the cultured broth of a fungal strain FO-7314. The strain was identified as Clonostachys sp. from the morphological characteristics. Argadin was purified from the cultured mycelium by a combination of cation exchange, adsorption and gel filtration chromatographic methods. The structure of argadin was elucidated as cyclo(Nomega-acetyl-L-arginyl-D-prolyl-homoseryl-histidyl-L- 2-aminoadipyl) in which homoseryl gamma-methylene bonded to histidyl alpha-amino residue. The IC50 value of argadin against Lucilia cuprina (blowfly) chitinase was 150 nM at 37 degrees C and 3.4 nM at 20 degrees C. Argadin arrested the moult of cockroach larvae upon injection into the ventral abdominal part.     

Studies on alkaline protease produced by Bacillus sp. NG312

An alkalophilic hyperproducer of alkaline protease, Bacillus sp. NG312, was isolated, and the enzyme showed maximum activity at pH 11.0 and 60°C. The temperature optimum was increased by 10°C in presence of Ca²⁺. The crudeenzyme was found to have half-life of 11 d at 37°C and maximum stability at pH 9.0–10.0. It also exhibited very good stability in presence of detergent components and some locally available commericial detergent powders.     

Characteriztion of a novel feather-degrading Bacillus sp. strain

Feather waste is generated in large amounts as a byproduct of commercial poultry processing. This residue is almost pure keratin, which is not easily degradable by common proteolytic enzymes. A feather-degrading bacterium was isolated from poultry feathers in decomposition. The strain identified as kr16 showed important feather-degrading activity when grown on basal medium containing 10 g/L of native feather as the source of energy, carbon, and nitrogen. The isolate was characterized according to the phenotypical characteristics and biochemical profiling that belong to the Bacillus genus. Keratinolytic activity of this isolate was monitored during cultivation of the bacterium on raw feathers at different temperatures. Maximum growth and feather-degrading activity were observed at 30–37°C. The keratinolytic enzyme had a pH optimum ranging from 8.0 to 11.0 and a temperature optimum of 45–65°C. The keratinase was strongly inhibited by EDTA and the metal ions Hg²⁺ and Sn²⁺.     

Synthesis of N2 2'-deoxyguanosine adducts formed by 1-nitropyrene

[reaction: see text] Synthesis of N(2) 2'-deoxyguanosine adducts formed by the ubiquitous carcinogen, 1-nitropyrene, is reported. Various conditions of Buchwald-Hartwig palladium-catalyzed amination are examined. The most convenient synthetic approach involved a straightforward coupling between protected 2'-deoxyguanosine and bromonitropyrenes, which, upon reductive deprotection, provided excellent yield of the two 1-nitropyrene adducts.     

Isolation and partial characterization of a biosurfactant mixture produced by Sphingobacterium sp. isolated from soil

The concentration decay curves for the adsorption of phenol on organobentonite were obtained in an agitated tank batch adsorber. The experimental adsorption rate data were interpreted with diffusional models as well as first-order, second-order and Langmuir kinetic models. The surface diffusion model adjusted the data quite well, revealing that the overall rate of adsorption was controlled by surface diffusion. Furthermore, the surface diffusion coefficient increased raising the mass of phenol adsorbed at equilibrium and was independent of the particle diameter in the range 0.042-0.0126 cm. It was demonstrated that the overall rate of adsorption was essentially not affected by the external mass transfer. The second-order and the Langmuir kinetic models fitted the experimental data quite well; however, the kinetic constants of both models varied without any physical meaning while increasing the particle size and the mass of phenol adsorbed at equilibrium.     

Azaspirene: a novel angiogenesis inhibitor containing a 1-oxa-7-azaspiro[4.4]non-2-ene-4,6-dione skeleton produced by the fungus Neosartorya sp

[structure: see text] Azaspirene isolated from the fungus Neosartorya sp. is a novel angiogenesis inhibitor with a 1-oxa-7-azaspiro[4.4]non-2-ene-4,6-dione skeleton. Azaspirene inhibits the endothelial migration induced by vascular endothelial growth factor (ED100 = 27.1 microM).     

Identification of novel sesterterpenes by genome mining of phytopathogenic fungi Phoma and Colletotrichum sp.

Two homologous gene clusters for the biosynthesis of sesterterpenes betaestacins were identified from two phytopathogens, Phoma betae and Colletotrichum orbiculare. Heterologous expression of identified oxidation enzymes with previously-characterized PbTS1 (BtcA_Pb) resulted in the production of seven novel sesterterpenes. Although both strains possessed homologous enzymes, oxidation state of corresponding products were different from each other, suggesting that structural diversification of sesterterpene skeletons might be achieved by these homologous enzymes with different functions.