7 research outputs found
Isolation, identification and characterization of endophytes from Cannabis sativa L. and Radula marginata
Endophytes Are Hidden Producers of Maytansine in Putterlickia Roots
Several recent studies have lent evidence to the fact that certain so-called plant metabolites are actually biosynthesized by associated microorganisms. In this work, we show that the original source organism(s) responsible for the biosynthesis of the important anticancer and cytotoxic compound maytansine is the endophytic bacterial community harbored specifically within the roots of Putterlickia verrucosa and P. retrospinosa plants. Evaluation of the root endophytic community by chemical characterization of their fermentation products using HPLC-HRMSn, along with a selective microbiological assay using the maytansine-sensitive type strain Hamigera avellanea revealed the endophytic production of maytansine. This was further confirmed by the presence of AHBA synthase genes in the root endophytic communities. Finally, MALDI-imaging-HRMS was used to demonstrate that maytansine produced by the endophytes is typically accumulated mainly in the root cortex of both plants. Our study, thus, reveals that maytansine is actually a biosynthetic product of root-associated endophytic microorganisms. The knowledge gained from this study provides fundamental insights on the biosynthesis of so-called plant metabolites by endophytes residing in distinct ecological niches
Endophytic <i>Diaporthe</i> sp. LG23 Produces a Potent Antibacterial Tetracyclic Triterpenoid
A new lanostanoid, 19-nor-lanosta-5(10),6,8,24-tetraene-1α,3ÎČ,12ÎČ,22<i>S</i>-tetraol (<b>1</b>), characterized by the presence
of an aromatic B ring and hydroxylated at C-1, C-3, C-12, and C-22,
was isolated from an endophytic fungus, <i>Diaporthe</i> sp. LG23, inhabiting leaves of the Chinese medicinal plant <i>Mahonia fortunei</i>. Six biosynthetically related known steroids
were also isolated in parallel. Their structures were confirmed on
the basis of detailed spectroscopic analysis in conjunction with the
published data. Compound <b>1</b>, an unusual fungus-derived
19-nor-lanostane tetracyclic triterpenoid with an aromatic B-ring
system, exhibited pronounced antibacterial efficacy against both Gram-positive
and -negative bacteria, especially the clinical isolates of <i>Streptococcus pyogenes</i> and <i>Pseudomonas aeruginosa</i> as well as a human pathogenic strain of <i>Staphylococcus aureus</i>. Our results reveal the potential of endophytes not only in conferring
host fitness but also in contributing toward traditional host plant
medicines
Antibacterial Azaphilones from an Endophytic Fungus, <i>Colletotrichum</i> sp. BS4
Three new compounds, colletotrichones
AâC (<b>1</b>â<b>3</b>), and one known compound,
chermesinone B (<b>4a</b>), were isolated from an endophytic
fungus, <i>Colletotrichum</i> sp. BS4, harbored in the leaves
of <i>Buxus sinica</i>, a well-known boxwood plant used
in traditional Chinese medicine
(TCM). Their structures were determined by extensive spectroscopic
analyses including 1D and 2D NMR, HRMS, ECD spectra, UV, and IR, as
well as single-crystal X-ray diffraction, and shown to be azaphilones
sharing a 3,6a-dimethyl-9-(2-methylbutanoyl)-9<i>H</i>-furoÂ[2,3-<i>h</i>]Âisochromene-6,8-dione scaffold. Owing to the remarkable
antibacterial potency of known azaphilones coupled to the usage of
the host plant in TCM, we evaluated the antibacterial efficacy of
the isolated compounds against two commonly dispersed environmental
strains of <i>Escherichia coli</i> and <i>Bacillus
subtilis</i>, as well as against two human pathogenic clinical
strains of <i>Staphylococcus aureus</i> and <i>Pseudomonas
aeruginosa</i>. Compound <b>1</b> exhibited marked antibacterial
potencies against the environmental strains that were comparable to
the standard antibiotics. Compound <b>3</b> was also active
against <i>E. coli</i>. Finally, compound <b>2a</b> exhibited the same efficacy as streptomycin against the clinically
relevant bacterium <i>S. aureus</i>. The <i>in vitro</i> cytotoxicity of these compounds on a human acute monocytic leukemia
cell line (THP-1) was also assessed. Our results provide a scientific
rationale for further investigations into endophyte-mediated host
chemical defense against specialist and generalist pathogens
Endophytes Are Hidden Producers of Maytansine in <i>Putterlickia</i> Roots
Several recent studies have lent
evidence to the fact that certain
so-called plant metabolites are actually biosynthesized by associated
microorganisms. In this work, we show that the original source organism(s)
responsible for the biosynthesis of the important anticancer and cytotoxic
compound maytansine is the endophytic bacterial community harbored
specifically within the roots of <i>Putterlickia verrucosa</i> and <i>P. retrospinosa</i> plants. Evaluation of the root
endophytic community by chemical characterization of their fermentation
products using HPLC-HRMS<sup><i>n</i></sup>, along with
a selective microbiological assay using the maytansine-sensitive type
strain <i>Hamigera avellanea</i> revealed the endophytic
production of maytansine. This was further confirmed by the presence
of AHBA synthase genes in the root endophytic communities. Finally,
MALDI-imaging-HRMS was used to demonstrate that maytansine produced
by the endophytes is typically accumulated mainly in the root cortex
of both plants. Our study, thus, reveals that maytansine is actually
a biosynthetic product of root-associated endophytic microorganisms.
The knowledge gained from this study provides fundamental insights
on the biosynthesis of so-called plant metabolites by endophytes residing
in distinct ecological niches