Complementary spectroscopy studies and potential activities of levan-type fructan produced by Bacillus paralicheniformis ND2.

This study aimed at the production of marine bacterial exopolysaccharides (EPS) as biodegradable and nontoxic biopolymers, competing the synthetic derivatives, with detailed structural and conformational analyses using spectroscopy techniques. Twelve marine bacterial bacilli were isolated from the seawater of Mediterranean Sea, Egypt, then screened for EPS production. The most potent isolate was identified genetically as Bacillus paralicheniformis ND2 by16S rRNA gene sequence of ~99 % similarity. Plackett-Burman (PB) design identified the optimization conditions of EPS production, which yielded the maximum EPS (14.57 g L-1) with 1.26-fold increase when compared to the basal conditions. Two purified EPSs namely NRF1 and NRF2 with average molecular weights (Mw¯) of 15.98 and 9.70 kDa, respectively, were obtained and subjected for subsequent analyses. FTIR and UV-Vis reflected their purity and high carbohydrate contents while EDX emphasized their neutral type. NMR identified the EPSs as levan-type fructan composed of ß-(2-6)-glycosidic linkage as a main backbone, and HPLC explained that the EPSs composed of fructose. Circular dichroism (CD) suggested that NRF1 and NRF2 had identical structuration with a little variation from the EPS-NR. The EPS-NR showed antibacterial activity with the maximum inhibition against S. aureus ATCC 25923. Furthermore, all the EPSs revealed a proinflammatory action through dose-dependent increment of expression of proinflammatory cytokine mRNAs, IL-6, IL-1ß and TNFα.

Production of Terretonin N and Butyrolactone I by Thermophilic Aspergillus terreus TM8 Promoted Apoptosis and Cell Death in Human Prostate and Ovarian Cancer Cells.

The anticancer activity of terretonin N (1) and butyrolactone I (2), obtained from the thermophilic fungus Aspergillus terreus TM8, was intensively studied against prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines. According to this study, both compounds showed potent cytotoxicity towards ovarian adenocarcinoma cells (SKOV3) with IC50 1.2 and 0.6 µg/mL, respectively. With respect to metastatic prostate cells (PC-3), the two compounds 1 and 2 showed a significantly promising cytotoxicity effect with IC50 of 7.4 and 4.5 µg/mL, respectively. The tested fungal metabolites showed higher rates of early and late apoptosis with little or no necrotic apoptotic pathway in all treated prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines, respectively. The results reported in this study confirmed the promising biological properties of terretonin N (1) and butyrolactone I (2) as anticancer agents via the induction of cellular apoptosis. However, further studies are needed to elucidate the molecular mechanism by which cellular apoptosis is induced in cancer cells.

Terretonin M: A new meroterpenoid from the thermophilic Aspergillus terreus TM8 and revision of the absolute configuration of penisimplicins.

Terretonin M (1), a new highly oxygenated tetracyclic meroterpenoid, was isolated from the thermophilic fungus Aspergillus terreus TM8 together with 10 known metabolites: terrelumamide A, asterrelenin, 7-prenyl-indolyl-3-carbaldehyde, (3ß,5α,6ß)-3,5,6-trihydroxy-ergosta-7,22-diene, sitostenone, linoleic acid, ergosterol, uracil, p-hydroxy-benzoic acid, and indole-3-carboxylic acid. The chemical structure of the new compound was elucidated by extensive 1D, 2D NMR, and ESI HR mass measurements, and by comparison with literature data. The absolute configuration of 1 was resolved by analysis of its NOESY spectrum and comparison of its experimental ECD spectrum with DFT calculations. In parallel to this work, revision of the absolute configuration of penisimplicins 3a and 3b is proposed on the basis of their ECD and ORD data. The isolation and taxonomic characterisation of A. terreus TM8 is reported, and the antimicrobial activity of the crude extract and the isolated compounds was studied as well.

A new diketopiperazine alkaloid from Aspergillus oryzae.

Investigation of bioactive secondary metabolites from terrestrial Aspergillus oryzae sp. MMAO1 using M2 medium afforded a new diketopiperazine alkaloid, 7,9-dihydroxy-3-(1H-indol-3-ylmethyl)-8-methoxy-2,3,11,11a-tetrahydro-6H-pyrazino[1,2-b]isoquinoline-1,4-dione (1a), containing the unusual amino acid L-6,8-dihydroxy-7-methoxyphenylalanine. This was co-isolated with ditryptophenaline (2), cyclo-(Tryp,Tyr) (4), cyclo-(Pro,Val), α-cyclopiazonic acid (3), kojic acid and uridine. Re-cultivation of the fungal strain on Dox medium led to the production of bisdethio(bismethylthio)gliotoxin (5), pseurotin A (6) along with linoleic acid, α-cyclopiazonic acid (3) and kojic acid. The chemical structure of the new diketopiperazine alkaloid including the relative configuration was determined by 1D and 2D NMR spectroscopy and HR-ESI-MS spectrometry, and by comparison with the related literature. The new alkaloid (1a) showed no antimicrobial activity or cytotoxicity against brine shrimps.

Mycobiota variation in stored rice straw and its cellulolytic profile.

Rice Straw (RS) one of most important agrowaste worldwide. Variation in mycobiota inhabiting long stored RS and its cellulolytic profile were studied. The highest number of fungi (23 species) was recovered from 1st storage period (1-3 year). Alternaria alternata, Aspergillus sp., Cladosporium herbarum, Fusarium incarnatum, Geotrichum candidum, Penicillium sp., Stemphylium lycopersici and Ulocladium atrum are the most frequent genera. Among 21 fungal species recovered in the 2nd period (3-5 year), Cladosporium herbarum, Fusarium incarnatum, Stemphylium lycopersici and Ulocladium atrum recorded 100% frequency, whereas Ulocladium atrum, Veticillium lecanii, Stemphylium lycopersici and Penicillium sp., were the most frequent species in the 3rd period (> 5 years). Regarding the pathogenic fungal isolates, Nigrospora oryzae was the most frequent with high intensity in all samples of the three storage periods, whereas Alternaria padwikii reached the highest frequency and intensity in the 1st period and absent the 2nd and 3rd ones. The isolated fungal species showed a high production of cellulases comparing to previous studies with positive and significant correlation between FPase from one side and CMCase (r = 0.634, p ≤ 0.05) and ß-glucosidase (r = 0.775, p ≤ 0.05) from the other side.

Molecular identification of a novel inulinolytic fungus isolated from and grown on tubers of Helianthus tuberosus and statistical screening of medium components.

Of 24 fungi belonging to more than five genera isolated from tubers of rotten Helianthus tuberosus, 11-inulinolytic active isolates were able to develop halo zones around their fungal colonies, indicating inulinase activity. Alternaria, Aspergillus, Fusarium, Pencillium and Trichoderma were the most common inulinolytic genera, representing more than 90 % of the total positive inulinolytic fungi. Aspergillus tamarii and Pencillium citrinum quantitatively recorded better growth (5.5 and 4.7 mg ml(-1)) and inulinase production (21.53 and 20.15 U ml(-1)) in submerged culture. The enzyme preparation showed also invertase activity. Aspergillus tamarii, as the most potent producer of inulinase, was identified using the Inter Transcribed Spacer marker. The sequence comparisons showed that our molecularly identified strain (GU295949) is related more closely to A. tamarii strains of the gene bank. Statistical screening using the fractional factorial Plackett-Burman design with 12 run was applied for screening ten variables, the low levels of pH (4.8), inoculum size (10(3) spore g(-1)), NH(4)NO(3) (1.0 mg g(-1)) and MgSO(4) (0.12 mg g(-1)), were the most significant variables on A. tamarii inulinase production. The high inulinase/invertase ratio (1.841-4.293) classified the enzyme preparation as inulinases, which can be used efficiently in production of fructose syrup from tubers of H. tuberosus.

Four butyrolactones and diverse bioactive secondary metabolites from terrestrial Aspergillus flavipes MM2: isolation and structure determination.

The chemical constituents and biological activities of the terrestrial Aspergillus flavipes MM2 isolated from Egyptian rice hulls are reported. Seven bioactive compounds were obtained, of which one sterol: ergosterol (1), four butyrolactones: butyrolactone I (2), aspulvinone H (3), butyrolactone-V (6) and 4,4'-diydroxypulvinone (7), along with 6-methylsalicylic acid (4) and the cyclopentenone analogue; terrien (5). Structures of the isolated compounds were deduced by intensive studies of their 1D & 2D NMR, MS data and comparison with related structures. The strain extract and the isolated compounds (1-7) were biologically studied against number of microbial strains, and brine shrimp for cytotoxicity. In this article, the taxonomical characterization of A. flavipes MM2 along with its upscale fermentation, isolation and structural assignment of the obtained bioactive metabolites, and evaluate their antimicrobial and cytotoxic activities were described.