Arthrobacter sp. JS443‐Based Whole Cell Amperometric Biosensor for p‐Nitrophenol

An amperometric microbial biosensor for highly sensitive and selective determination of p‐nitrophenol (PNP) is reported. The biosensor consisted of PNP‐degrader Arthrobacter sp. JS443 immobilized by entrapment in Nafion polymer deposited on the top of the carbon paste electrode transducer. The biosensor was based on the measurement of the oxidation current of the intermediates 4‐nitrocatechol and 1,2,4‐benzenetriol formed by the highly selective oxidation of PNP by Arthrobacter sp. The sensor signal and response time were optimized with applied potential of +0.4 V (vs. Ag/AgCl reference electrode) and 0.03 mg of cells and operating in pH 7.5, 50 mM citrate‐phosphate buffer at room temperature. When operated at optimized conditions, the Arthrobacter sp.‐based biosensor measured as low as 5 nM (0.7 ppb) of PNP. The biosensor demonstrated excellent selectivity with no interference from phenolic compounds such as 2‐nitrophenol, phenol and 3‐chlorophenol but was interfered by 3‐nitrophenol and 3‐methyl‐4‐nitrophenol. It had good precision and intra‐ and inter‐day reproducibility, accuracy and was stable up to 3 days when stored in buffer at 4 °C. When applied for measurement in water from Lake Elsinore, CA, the results obtained were in excellent agreement with the amounts determined spectrophotometrically.     

豆荚软珊瑚Lobophytum sp. 的次生代谢产物研究

从海南岛三亚海域采集的软珊瑚Labophytumsp.中分离得五个甾醇苷(1)～(5)。通过波谱分析，确定它们的化学结构依次为3'-O-乙酰基-4-O-[β-D-吡喃木糖苷]-孕甾-20-烯-3β,4α-二醇(1)，4-O-[β-D-吡喃木糖苷]-孕甾-20-烯-3β,4α-二醇(2),4'-O-乙酰基-4-O-[β-D-吡喃木糖苷]-孕甾-20-烯-3β,4α-二醇(3),4'-O-乙酰基-4-O-[β-D-吡喃阿拉伯糖苷]-孕甾-20-烯-3β,4α-二醇(4)和4-O-[β-D-吡喃阿拉伯糖苷]-孕甾-20-烯-3β,4α-二醇(5),其中1为新化合物。体外细胞毒性实验表明：化合物(1),(2)和(5)对SKMG-4,Hep-G2和CNE2三种人体癌细胞具有抑制作用。     

苯甲酸氯代衍生物稀土配合物的荧光表征

分别以典型的芳香羧酸苯甲酸及其一氯代衍生物（邻、间、对三种）为第一配体,以邻菲罗啉(phen)或2,2′ 联吡啶((bipy)为第二配体,合成了一系列Tb(III)、Eu(III)的配合物.通过红外光谱、紫外可见光谱、荧光光谱等方法探讨了不同位置的取代基或不同的第二配体对配合物荧光性质的影响.结果显示,邻菲罗啉能够增强Eu(III)芳香羧酸配合物的荧光强度而减弱Tb(III)羧酸配合物的荧光强度;2,2′ 联吡啶则显示相反的结果.     

Production of chitinolytic enzymes with Trichoderma longibrachiatum IMI 92027 in solid substrate fermentation

Thirty Trichoderma strains representing 15 species within the genus were screened for extracellular production of chitinolytic enzymes in solid substrate fermentation. Trichoderma longibrachiatum IMI 92027 (ATCC 36838) gave the highest yield (5.0 IU/g of dry matter of substrate) after 3 d of fermentation on wheat bran-crude chitin (9:1 mixture) medium. The optimal moisture content (66.7%), chitin content (20%), initial pH of the medium (2.0–5.0), and time course (5 d) of solid substrate fermentation were determined for strain IMI 92027. Cellulase, xylanase, α-amylase, and β-xylosidase activities were also detected. The pH and temperature optima of the chitinase complex of T. longibrachiatum IMI 92027 were 4.5 and 55°C, respectively. The enzyme totally lost its activity at 70°C in 5 min in the absence of the substrate but retained about 15% of its initial activity even at 70°C after a 60-min incubation in the presence of solid substrate fermentation solids. Purification of protein extract from the solid substrate fermentation material revealed high chitinolytic activities between pI 5.9 and 4.8, where N-acetyl-β-d-hexosaminidase and chitinase peaks have been found in the same pI range. Two chitinases of 43.5 and 30 kDa were purified at acidic pI.     

Wickerols A and B: novel anti-influenza virus diterpenes produced by Trichoderma atroviride FKI-3849

Wickerols A and B were produced by a fungus, Trichoderma atroviride FKI-3849. Wickerol A showed potent anti-influenza virus activity against strain A/PR/8/34 (H1N1), whereas wickerol B exhibited weaker impact. The anti-influenza virus spectrum between wickerols A and B was different. The cyclization mechanism of the wickerol carbon-skeleton was investigated by incorporation of ¹³C-labeled acetate. A pathway through the verticillyl cation was predicted.     

A Theoretical Investigation on N7(H)→N9(H)Tautomerization of Isolated and Monohydrated 2,6-Dithiopurine Combined with IPCM Solvent Model

The tautomerization reaction mechanism has been reported between N7(H) and N9(H) of isolated and monohydrated 2,6‐dithiopurine using B3LYP/6‐311+G(d,p). The isodensity polarized continuum model (IPCM) in the self‐consistent reaction field (SCRF) method is employed to account for the solvent effect of water on the tautomerization reaction activation energies. The results show that the two pathways P(1) (via the carbene intermediate I1) and P(2) (via the sp³‐hybrid intermediate I2) are found in intramolecular proton transfer, and each pathway is composed by two primary steps. The calculated activation energy barriers of the rate‐determining steps in isolated 2,6‐dithiopurine N7(H)→N9(H) tautomerism are 308.2 and 220.0 kJ·mol^?1 in the two pathways, respectively. Interestingly, in one‐water molecule catalyst, it dramatically lowers the N7(H)→N9(H) energy barriers by the concerted double proton transfer mechanism in P(1), favoring the formation of 2,6‐dithiopurine N9(H). However, the single proton transfer mechanism assisted with out‐of‐plane water in the first step of P(2) increases the activation energy barrier from 220.0 to 232.3 kJ·mol^?1, while the second step is the out‐of‐plane concerted double proton transfer mechanism, indicating that they will be less preferable for proton transfer. Additionally, the results also show that all the pathways are put into the aqueous solution, and the activation energy barriers have no significant changes. Therefore, the long‐range electrostatic effect of bulk solvent has no significant impact on proton transfer reactions and the interaction with explicit water molecules will significantly influence proton transfer reactions.     

Salarins D-J, seven new nitrogenous macrolides from the madagascar sponge Fascaplysinopsis sp.

Seven new nitrogenous macrolides, designated salarins D-J (4-10), closely related to salarins A-C (1-3), have been isolated from the Madagascar Fascaplysinopsis sp. sponge. The structure and relative stereochemistry of compounds 4-10 were elucidated by interpretation of MS, COSY, HSQC, HMBC, and NOESY spectra. Salarin B's structure (2), based on the structure of salarin J (10), is now amended to also incorporate the C-14 to -17 THF ring system. All compounds were evaluated for their cytotoxicity against K562 and UT-7 human leukemia cells. While salarins D, E, H, and J displayed dose and time dependent inhibition of proliferation, salarins F and I were not active in these assays.     

Seimatoric acid and colletonoic acid:Two new compounds from the endophytic fungi,Seimatosporium sp.and Colletotrichum sp.

A new metabolite,named seimatoric acid(1),representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz.,2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone(2),(-)-phyllostine(3),(+)-epiepoxydon(4) and(+)-epoxydon monoacetate(5).Similarly one new benzoic acid derivative,named colletonoic acid(6) was isolated from the ethyl acetate fraction of Colletotrichum sp.The structures of the new compounds were elucidated by detailed ~1 H NMR,~(13)C NMR,COSY,HMQC.HMBC spectroscopic analysis,and HR-E1-MS.Seimatoric acid(1)was also isolated from another taxonomical unidentified fungal strain 4295 in ourgroup.The structures of the known compounds were elucidated by their spectral data comparison to literature data.Preliminary studies showed that colletonoic acid(6) showed good antibacterial,antifungal,and antialgal activities.     

Structure determination of two new indole‐diterpenoids from Penicillium sp. CM‐7 by NMR spectroscopy

Two new indole‐diterpenoids 4b‐deoxy‐1′‐O‐acetylpaxilline (1) and 4b‐deoxypenijanthine A (2) were isolated from the fermentation broth and the mycelia of the soil fungus Penicillium sp. CM‐7, along with three known structurally related compounds, 1′‐O‐acetylpaxilline (3), paspaline (4) and 3‐deoxo‐4b‐deoxypaxilline (5). The structures of compounds 1 and 2 were elucidated by extensive spectroscopic methods, especially 2D NMR, and their absolute configurations were suggested on the basis of the circular dichroism spectral analysis and the NOESY data. Copyright © 2014 John Wiley & Sons, Ltd.     

Production of β-galactosidase by Trichoderma reesei FTKO-39 in wheat bran

Trichoderma reesei FTKO-39 grown at 35°C for 5 d on wheat bran supplemented with MgCl₂ and lactose as the carbon source produced two isozymes of β-galactosidase: BGT I and BGT II. These isozymes were partially purified on a DEAE-Trisacryl column. Both BGT I and BGT II fractions exhibited optimum activity at 65°C, but the pH optima were 4.0 and 6.5, respectively. The isozymes also showed similar thermal stability. However, BGT I was more stable than BGT II in a pH range of 3.0–10.0. At least two different β-galactosidases are produced by T. reesei, as revealed by the two bands seen on a 6% polyacrylamide gel stained for activity.