Induction of Isochromanones by Co-Cultivation of the Marine Fungus Cosmospora sp. and the Phytopathogen Magnaporthe oryzae

Microbial co-cultivation is a promising approach for the activation of biosynthetic gene clusters (BGCs) that remain transcriptionally silent under artificial culture conditions. As part of our project aiming at the discovery of marine-derived fungal agrochemicals, we previously used four phytopathogens as model competitors in the co-cultivation of 21 marine fungal strains. Based on comparative untargeted metabolomics analyses and anti-phytopathogenic activities of the co-cultures, we selected the co-culture of marine Cosmospora sp. with the phytopathogen Magnaporthe oryzae for in-depth chemical studies. UPLC-MS/MS-based molecular networking (MN) of the co-culture extract revealed an enhanced diversity of compounds in several molecular families, including isochromanones, specifically induced in the co-culture. Large scale co-cultivation of Cosmospora sp. and M. oryzae resulted in the isolation of five isochromanones from the whole co-culture extract, namely the known soudanones A, E, D (1-3) and their two new derivatives, soudanones H-I (4-5), the known isochromans, pseudoanguillosporins A and B (6, 7), naphtho-γ-pyrones, cephalochromin and ustilaginoidin G (8, 9), and ergosterol (10). Their structures were established by NMR, HR-ESIMS, FT-IR, electronic circular dichroism (ECD) spectroscopy, polarimetry ([α]D), and Mosher’s ester reaction. Bioactivity assays revealed antimicrobial activity of compounds 2 and 3 against the phytopathogens M. oryzae and Phytophthora infestans, while pseudoanguillosporin A (6) showed the broadest and strongest anti-phytopathogenic activity against Pseudomonas syringae, Xanthomonas campestris, M. oryzae and P. infestans. This is the first study assessing the anti-phytopathogenic activities of soudanones.

(±)-Usphenethylones A−C, three pairs of heterodimeric polyketide enantiomers from Aspergillus ustus 3.3904

Three pairs of novel heterodimeric polyketide enantiomers, (±)-usphenethylones A−C (1−3), were isolated from the culture extract of Aspergillus ustus 3.3904. Compounds 1−3 represent two unique heterodimerization patterns of a phenethyl...

Mg, K-containing microparticle: A possible active principle of a culture extract produced by a microbial consortium

A synthetic microbial consortium called Effective Microorganisms (EM) consists mainly of photosynthetic bacteria, lactic acid bacteria and yeast. Various effects of EM∙XGOLD, a health drink produced by EM, on life cycle of Dictyostelium discoideum were described previously. Here, we report our attempt to identify the active principle, termed EMF, that brought about the observed effects. Throughout the purification processes, the presence of the active principle was monitored by promoted fruiting body formation. By liquid-liquid separation the activity was recovered in aqueous phase, which, after concentration, was further subjected to reverse-phase column chromatography. No activity was detected in any eluant, while almost all the activity was recovered in residual insoluble material. The application of conventional organic chemistry procedures to the residual fraction did not lead to any informative results. Acid treatment of the insoluble material produced air bubbles, suggesting it to be composed of some inorganic carbonate. Viewed under scanning electronmicroscope, the residue revealed spherical particles of μm size range. Energy Dispersive X-ray (EDX) Spectroscopy pointed to the existence, on the surface of the particles, of magnesium and, to a certain extent, of potassium. In separate experiments, acid treatment and alkali neutralization of EM∙XGOLD completely wiped out the stimulatory activity of fruiting body formation. These lines of evidence indicate these Mg, K-containing microparticles to be an active principle of EM culture extract. How these particles exert their effect is currently under intensive investigation.

UPLC-QTOF-MS-Based Untargeted Study of Metabolites Secreted by Sclerotinia Sclerotiorum Pathogen Under Axenic Condition

The stem rot disease has emerged globally as a major disease threat to the productivity and seed quality of oilseed Brassica. The generalist causal pathogen Sclerotinia sclerotiorum (Lib.) de Bary shows large variability in their aggressiveness and pathogenicity. Revealing the metabolic profile and signaling components of the pathogen in host-pathogen interaction are fundamental in understanding host resistance to the disease. In this study, the metabolites released by the pathogenic strains of S. sclerotiorum under the axenic culture have been identified using the untargeted high-resolution UPLC-QTOF-ESI-MS/MS. The analysis of the ethyl acetate extracts of the S. sclerotiorum culture revealed ten major secondary metabolites namely, sclerin, sclerotinin-B, sclerone, melanin, bostrycoidin, botcinin-D, botcinin-A, gliovirin, scleramide, and botcinic acid. The later six metabolites are being reported for the first time in the culture extract of the S. sclerotiorum pathogen. The phylogenetic analysis based on the overlapping and unique informative peaks in the chromatograms, the six S. sclerotiorum strains were grouped into three major clads. The clustering based on metabolic profiles does not substantiate the diversity based on morphology or virulence differences on the host. The findings of the study signified the metabolites secreted under the axenic conditions are varies based on their growth and developmental stages and may not necessarily be the determining factors for their differential aggressiveness and virulence over the host.

Luteapyrone, a Novel ƴ-Pyrone Isolated from the Filamentous Fungus Metapochonia lutea.

In the process of screening for new bioactive microbial metabolites we found a novel ƴ-pyrone derivative for which we propose the trivial name luteapyrone, in a recently described microscopic filamentous fungus, Metapochonia lutea BiMM-F96/DF4. The compound was isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structure was elucidated by NMR and LC-MS. The new compound was found to be non-cytotoxic against three mammalian cell lines (HEK 263, KB-3.1 and Caco-2). Similarly, no antimicrobial activity was observed in tested microorganisms (gram positive and negative bacteria, yeast and fungi).

Thermal stable and proteinase-K resistant insecticidal toxins produced by Photorhabdus luminescens

Photorhabdus is lives in a mutualistic association with nematodes from the family Heterorhabditis. Bacteria of the Photorhabdus can survive independently and cause toxicity in a larger variety of insects. In the present study, insecticidal activity of non-portentous heat-stable metabolites of Photorhabdus luminescens was evaluated against Galleria mellonella. For this purpose, the culture extract of P. luminescens was injected into the G. mellonella larvae, which killed almost 90% of larvae within 48 h. The extract showed 100% insecticidal activity after heat treatment of 70 C for 30 min and even 60% and 40% activity lasted at 80 C and 90 C respectively. The extract also showed a high degree of thermal stability and was 100% actives after 60 min at 70 C. In addition, insecticidal activity was preserved up to 100% after all proteinase-K treatments (0 ?g/mL to 50 ?g/mL). The results revealed that the extracts were non-portentous and showed high thermal resistance and stability. Keywords: Photorhabdus, insecticidal activity, toxins, heat stable non-proteinaceous

Research on Urban Brand Image Design Integrating Regional Culture

Urban brand image essentially reflects the regional culture, revealing the core spirit and culture of the city, and embodies value pursuit and development concept, which shows spiritual symbol of unique distinctive and specific temperament. To enhance the internal cohesion and arouse the cognition of city brand, it is vital to make the city brand known worldwide. We should deeply tap the profound connotation of regional culture, extract elements, strive to create a more attractive city image, and create unique regional culture of an internationally influential brand.

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

Three new tetronate-class polyketides, nomimicins B, C, and D, along with nomimicin, hereafter named nomimicin A, were isolated from the culture extract of Actinomadura sp. AKA43 collected from floating particles in the deep-sea water of Sagami Bay, Japan. The structures of nomimicins B, C, and D were elucidated through the interpretation of NMR and MS analytical data, and the absolute configuration was determined by combination of NOESY/ROESY and ECD analyses. Nomimicins B, C, and D showed antimicrobial activity against Gram-positive bacteria, Kocuria rhizophila and Bacillus subtilis, with MIC values in the range of 6.5 to 12.5 μg/mL. Nomimicins B and C also displayed cytotoxicity against P388 murine leukemia cells with IC50 values of 33 and 89 μM, respectively.

Polyphasic Approach Utilized for the Identification of Two New Toxigenic Members of Penicillium Section Exilicaulis, P. krskae and P. silybi spp. nov.

Two new species, Penicillium krskae (isolated from the air as a lab contaminant in Tulln (Austria, EU)) and Penicillium silybi (isolated as an endophyte from asymptomatic milk thistle (Silybum marianum) stems from Josephine County (Oregon, USA)) are described. The new taxa are well supported by phenotypic (especially conidial ornamentation under SEM, production of red exudate and red pigments), physiological (growth at 37 °C, response to cycloheximide and CREA), chemotaxonomic (production of specific extrolites), and multilocus phylogenetic analysis using RNA-polymerase II second largest subunit (RPB2), partial tubulin (benA), and calmodulin (CaM). Both new taxa are resolved within the section Exilicaulis in series Restricta and show phylogenetic affiliation to P. restrictum sensu stricto. They produce a large spectrum of toxic anthraquinoid pigments, namely, monomeric anthraquinones related to emodic and chloremodic acids and other interesting bioactive extrolites (i.e., endocrocin, paxilline, pestalotin, and 7-hydroxypestalotin). Of note, two bianthraquinones (i.e., skyrin and oxyskyrin) were detected in a culture extract of P. silybi. Two new chloroemodic acid derivatives (2-chloro-isorhodoptilometrin and 2-chloro-desmethyldermoquinone) isolated from the exudate of P. krskae ex-type culture were analyzed by nuclear magnetic resonance (NMR) and liquid chromatography–mass spectrometry (LC–MS).