https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

All plants are inhabited internally by diverse microbial communities comprising bacterial, archaeal, fungal, and protistic taxa. These microorganisms showing endophytic lifestyles play crucial roles in plant development, growth, fitness, and diversification. The increasing awareness of and information on endophytes provide insight into the complexity of the plant microbiome. The nature of plant-endophyte interactions ranges from mutualism to pathogenicity. This depends on a set of abiotic and biotic factors, including the genotypes of plants and microbes, environmental conditions, and the dynamic network of interactions within the plant biome. In this review, we address the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.

The Hidden World within Plants: Ecological and Evolutionary Considerations for Defining Functioning of Microbial Endophytes

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Biology and chemistry of endophytes.

http://orton.catie.ac.cr/repdoc/A4828i/A4828i.pdf

Understanding the diversity of foliar endophytic fungi: progress, challenges, and frontiers

This review focuses on new endophyte-related findings in biology and ecology, and also summarises the various metabolites isolated from endophytes.

Biology and Chemistry of Endophytes

Immunosuppressants are required for an array of medical purposes, such as organ transplantations and the treatment of autoimmune-associated diseases. However, most of the currently available immunosuppressive drugs have been shown to inevitably possess severe adverse effects, such as hepatotoxicity, nephrotoxicity, and hypertension induction. Therefore, there is an urgent need for new therapeutic agents for modulating the autoimmune response. Some microorganisms are a reliable source of immunocompromising compounds, as exemplified by the discovery of cyclosporin A (CsA), rapamycin, and FK506. Symbionts, a diverse microbial community present in plants, insects, and mammals without the generation of any detectable symptoms, are receiving renewed attention for their production of chemically inspiring and biologically potent metabolites, presumably as a result of their long coevolution with hosts. In particular, some insect-associated fungi might have acquired instinctlike capabilities for synthesizing immunoalleviating metabolites from their initial microbe–host interaction through to the final colonization. In continuation of our characterization of new bioactive metabolites from endophyte cultures, this observation tempted us to explore novel immunosuppressive metabolites that could be produced by fungi inhabiting healthy insect organs, such as the mantis gut, which is clearly an important entrance and shelter for symbionts (including quiescent pathogens) and meal-carried “foreign” microbes. As expected, a preliminary screen recognized the presence of an immunosuppressive substance or immunosuppressive substances in a culture of Daldinia eschscholzii IFB-TL01 residing in the gut of the mantis species Tenodera aridifolia, a common predator of many insects that feed on plants harboring endophyte. Subsequent bioassay-guided fractionation of the extract derived from the scaled-up fermentation of the fungus afforded two polyketides, dalesconols A (1) and B

Unprecedented Immunosuppressive Polyketides from Daldinia eschscholzii, a Mantis‐Associated Fungus

Penicidones A-C, three cytotoxic alkaloidal metabolites of an endophytic Penicillium sp.

Two new alkaloids chaetoglobosins V ( 1) and W ( 2), together with the six known congeners 3- 8, were isolated through bioassay-guided fractionations from the EtOAc extract of a solid culture of CHAETOMIUM GLOBOSUM IFB-E041. The structures were elucidated by spectroscopic methods including mainly 1D and 2D NMR techniques. Chaetoglobosin W ( 2) was unique in its possession of an oxolane ring formed via an oxygen bridge between C-3 and C-6. The isolated fungal metabolites exhibited moderate cytotoxic activities against four human cancer cell lines (KB, K562, MCF-7, and HepG2) with their IC 50 values in a range of 18-30 μg/mL.

Yong Chun Song

Papers

Biology and chemistry of endophytes.

Biology and Chemistry of Endophytes

Unprecedented Immunosuppressive Polyketides from Daldinia eschscholzii, a Mantis‐Associated Fungus

Penicidones A-C, three cytotoxic alkaloidal metabolites of an endophytic Penicillium sp.

Cytotoxic chaetoglobosins from the endophyte Chaetomium globosum.