Optimizing conditions of mycelial inoculum immobilized in Ca-alginate beads: a case study in ectomycorrhizal fungus Astraeus odoratus.

Ectomycorrhizal inoculum has emerged as a critical tool for forest restoration, especially under challenging climate change conditions. The inoculation of selective ectomycorrhizal fungi can enhance seedling survival and subsequent growth in the field. This study optimized the liquid media for mycelial growth of Astraeus odoratus strain K1 and the sodium alginate solution composition for enhanced mycelial viability after entrapment. Using Modified Melin-Norkrans as the optimal media for mycelial cultivation and 2% sodium alginate supplemented with Czapek medium, 0.25% activated charcoal, 5% sucrose, and 5% sorbitol in the alginate solution yielded the highest viability of A. odoratus mycelia. Preservation in distilled water and 10% glycerol at 25 °C for 60 days proved to be the most effective storage condition for the alginate beads. Both fresh and preserved alginate beads were tested for colonizing on Hopea odorata Roxb. seedlings, showing successful colonization and ectomycorrhizal root formation, with over 49% colonization. This study fills a crucial gap in biotechnology and ectomycorrhizal inoculum, paving the way for more effective and sustainable forest restoration practices.

Aspergillus niger upregulated glycerolipid metabolism and ethanol utilization pathway under ethanol stress.

The knowledge of how Aspergillus niger responds to ethanol can lead to the design of strains with enhanced ethanol tolerance to be utilized in numerous industrial bioprocesses. However, the current understanding about the response mechanisms of A. niger toward ethanol stress remains quite limited. Here, we first applied a cell growth assay to test the ethanol tolerance of A. niger strain ES4, which was isolated from the wall near a chimney of an ethanol tank of a petroleum company, and found that it was capable of growing in 5% (v/v) ethanol to 30% of the ethanol-free control level. Subsequently, the metabolic responses of this strain toward ethanol were investigated using untargeted metabolomics, which revealed the elevated levels of triacylglycerol (TAG) in the extracellular components, and of diacylglycerol, TAG, and hydroxy-TAG in the intracellular components. Lastly, stable isotope labeling mass spectrometry with ethanol-d6 showed altered isotopic patterns of molecular ions of lipids in the ethanol-d6 samples, compared with the nonlabeled ethanol controls, suggesting the ability of A. niger ES4 to utilize ethanol as a carbon source. Together, the studies revealed the upregulation of glycerolipid metabolism and ethanol utilization pathway as novel response mechanisms of A. niger ES4 toward ethanol stress, thereby underlining the utility of untargeted metabolomics and the overall approaches as tools for elucidating new biological insights.

Architrypethelium murisporum (Ascomycota, Trypetheliaceae), a remarkable new lichen species from Thailand challenging ascospore septation as an indicator of phylogenetic relationships.

Architrypethelium murisporum Luangsuphabool, Lumbsch & Sangvichien is described for a crustose lichen occurring in dry evergreen forest in Thailand. It is characterised by a green to yellow-green corticated thallus, perithecia fused in black pseudostromata with white rim surrounding the ostiole and small, hyaline and muriform ascospores. Currently, all species in the genus Architrypethelium have transversely septate ascospores, hence the discovery of this new species indicates that ascospore septation is variable within the genus, similar to numerous other groups of lichen-forming ascomycetes. Phylogenetic analyses of two loci (mtSSU and nuLSU) supported the position of the new species within Architrypethelium. This is the first report of the genus in Southeast Asia.

Efficiency of the formulated plant-growth promoting Pseudomonas fluorescens MC46 inoculant on triclocarban treatment in soil and its effect on Vigna radiata growth and soil enzyme activities.

For bioaugmentation-based treatment of triclocarban (TCC), an emerging soil pollutant that is recalcitrant to biodegradation and phytotransformation, efficient TCC-degrading bacteria with an effective soil-delivering means are required. This work developed the formulated bacterial inoculant, and successfully demonstrated its TCC removal and detoxification performance in pot soil experiment with Vigna radiata plants. The soil bacterium Pseudomonas fluorescens MC46 was isolated as TCC-degrading, plant-growth promoting bacterium. The characterizations were conducted in vitro revealing that it could utilize TCC as a sole carbon source, and at a wide and higher concentration range from 1.6-31.6mgkg-1 than those previously reported, while the detoxification was assessed by cytogenotoxicity and phytotoxicity tests. The developed sawdust-based inoculant formula combined with molasses (5% w/w), and either PEG or CMC-starch blend (1% w/w) could maintain a 20-week shelf-life inoculant stability in terms of cell viability, and TCC-degrading activity. Bioaugmentation of the formulated inoculants into TCC-contaminated soil efficiently removed TCC up to 74-76% of the initial concentration, mitigated toxicity, restored plant growth and health, and enhanced soil enzyme activities. This work is the first to demonstrate potential application of the formulated plant-growth promoting bacterial inoculant for the treatment and detoxification of a persistent TCC contaminated in soil.

Biotransformation of ent-kaur-16-en-19-oic acid by Psilocybe cubensis.

Biotranformation of ent-kaur-16-en-19-oic acid (1) using Psilocybe cubensis resulted in hydroxylated products. After two days of incubation, ent-16beta,17-dihydroxy-kauran-19-oic acid (2) was isolated. After further incubation for nine days, two novel metabolites, ent-12alpha,16beta,17-trihydroxy-kauran-19-oic acid (3) and ent-11alpha,16beta,17-trihydroxy-kauran-19-oic acid (4), were obtained. The metabolites were identified by spectroscopic methods and X-ray crystallography. Compounds 1-4 were evaluated for their cytotoxic properties against the human leukaemia K562 cell line; only compound 1 showed moderate activity.

A new sesquiterpenoid metabolite from Psilocybe samuiensis.

A novel 2,3-secoaromadendrane-type sesquiterpenoid metabolite, psilosamuiensin A (1), was isolated from the broth of Psilocybe samuiensis. The structure of psilosamuiensin A was established by spectroscopic data and its configurations were confirmed by single crystal X-ray crystallographic analysis. This is the first report of psilosamuiensin A found in the genus Psilocybes.

Biodegradation of benzo(a)pyrene by a newly isolated Fusarium sp.

Benzo(a)pyrene (BaP) is a five-ring polycyclic aromatic hydrocarbon produced by the incomplete combustion of organic materials. It is one of the priority pollutants listed by the US Environmental Protection Agency. This study describes a fungal isolate that is able to biodegrade benzo(a)pyrene. The filamentous fungus, isolated from leaves of Pterocarpus macrocarpus Kurz., was identified as a Fusarium sp. (strain E033). Fusarium sp. E033 was able to survive in the presence of benzo(a)pyrene concentrations up to 1.2 mM (300 mg L(-1)). Biodegradation experiments using 0.4 mM (100 mg L(-1)) benzo(a)pyrene demonstrated that Fusarium sp. E033 was able to degrade 65-70% of the initial benzo(a)pyrene provided, and two transformation products, a dihydroxy dihydro-benzo(a)pyrene and a benzo(a)pyrene-quinone, were detected within 30 days of incubation at 32 degrees C. The factors affecting biodegradation efficiency were also investigated. While increasing aeration promoted better fungal growth and benzo(a)pyrene biodegradation, increasing the glucose concentration from 5 to 50 mM had an adverse effect on biodegradation. Ethanol and methanol, provided at 5 mM to increase benzo(a)pyrene water solubility, increased the fungal biomass yield but did not promote degradation. The Fusarium sp. E033 isolated in this study can tolerate and degrade relatively high concentrations of benzo(a)pyrene, suggesting its potential application in benzo(a)pyrene bioremediation.

Cytotoxic activity of four xanthones from Emericella variecolor, an endophytic fungus isolated from Croton oblongifolius.

Four xanthones were isolated from mycelia of Emericella variecolor, an endophytic fungus isolated from the leaves of Croton oblongifolius. Their structures were elucidated by spectroscopic analysis to be shamixanthone, 14-methoxytajixanthone-25-acetate, tajixanthone methanoate, and tajixanthone hydrate. All compounds were tested for cytotoxic activity against various human tumor cell lines including gastric carcinoma, colon carcinoma, breast carcinoma, human hepatocarcinoma, and lung carcinoma. The antitumor activities of these xanthones were compared with that of doxorubicin hydrochloride, a chemotherapeutic substance. All of them showed moderate activities and were selective against gastric carcinoma, colon carcinoma, and breast carcinoma. Only tajixanthone hydrate exhibited moderate activity against all cancer cell lines. Furthermore, under the test conditions it was found that 14-methoxytajixanthone-25-acetate and tajixanthone hydrate are almost as active as doxorubicin hydrochloride against gastric carcinoma (KATO3) and breast carcinoma (BT474).