Immunosuppressive compounds of Pestalotiopsis sp., an endophytic fungus of Tripterygium wilfordii

published_or_final_versio

Immunomodulatory activity of Pestalotiopsis sp., an endophytic fungus from Tripterygium wilfordii

published_or_final_versio

Core charge distribution and self assembly of columnar phases: the case of triphenylenes and azatriphenylenes

<p>Abstract</p> <p>Background</p> <p>The relation betweeen the structure of discotic molecules and columnar properties, a crucial point for the realization of new advanced materials, is still largely unknown. A paradigmatic case is that hexa-alkyl-thio substituted triphenylenes present mesogenic behavior while the corresponding azatriphenylenes, similar in shape and chemical structure, but with a different core charge distribution, do not form any liquid crystalline mesophase. This study is aimed at investigating, with the help of computer simulations techniques, the effects on phase behaviour of changes of the charge distribution in the discotic core.</p> <p>Results</p> <p>We described the shape and the pair, dispersive and electrostatic, interactions of hexa alkyl triphenylenes by uniaxial Gay-Berne discs with embedded point charges. Gay-Berne parameters were deduced by fitting the dispersive energies obtained from an atomistic molecular dynamics simulation of a small sample of hexa-octyl-thio triphenylene molecules in columnar phase, while a genetic algorithm was used to get a minimal set of point charges that properly reproduces the ab anitio electrostatic potential. We performed Monte Carlo simulations of three molecular models: the pure Gay-Berne disc, used as a reference, the Gay-Berne disc with hexa-thio triphenylene point charges, the Gay-Berne disc with hexa-thio azatriphenylene point charges. The phase diagram of the pure model evidences a rich polymorphism, with isotropic, columnar and crystalline phases at low pressure, and the appearance of nematic phase at higher pressure.</p> <p>Conclusion</p> <p>We found that the intermolecular electrostatic potential among the cores is fundamental in sta-bilizing/destabilizing columnar phases; in particular the triphenylene charge distribution stabilizes the columnar structure, while the azatriphenylene distribution suppresses its formation in favor of the nematic phase. We believe the present model could be successfully employed as the basis for coarse-grained level simulations of a wider class of triphenylene derivatives.</p

The hidden world within plants: ecological and evolutionary considerations for defining functioning of microbial endophytes

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.EU Cost Action [FA1103, 312117]; FWF (Austrian Science Foundation) [P26203-B22, P24569-B25]; Portuguese FCT (Foundation for Science and Technology) [SFRH/BPD/78931/2011]info:eu-repo/semantics/publishedVersio

Entomopathogenic Fungi on Hemiberlesia pitysophila

Hemiberlesia pitysophila Takagi is an extremely harmful exotic insect in forest to Pinus species, including Pinus massoniana. Using both morphological taxonomy and molecular phylogenetics, we identified 15 strains of entomogenous fungi, which belong to 9 genera with high diversities. Surprisingly, we found that five strains that were classified as species of Pestalotiopsis, which has been considered plant pathogens and endophytes, were the dominant entomopathogenic fungus of H. pitysophila. Molecular phylogenetic tree established by analyzing sequences of ribosomal DNA internal transcribed spacer showed that entomopathogenic Pestalotiopsis spp. were similar to plant Pestalotiopsis, but not to other pathogens and endophytes of its host plant P. massoniana. We were the first to isolate entomopathogenic Pestalotiopsis spp. from H. pitysophila. Our findings suggest a potential and promising method of H. pitysophila bio-control

Immunomodulatory compounds from Pestalotiopsis leucothes, an endophytic fungus from Tripterygium wilfordii

[[abstract]]The immunomodulatory effects of three compounds designated BS, GS, and YS produced by Pestalotiopsis leucothes, an endophytic fungus isolated from Tripterygium wilfordii, were evaluated. The 50% inhibition concentration (IC50) value of BS in the proliferative assay with various stimulating agents such as phytohemagglutinin-M (PHA-M), phorbol myristate acetate (PMA)/ionomycin, mixed lymphocyte reaction (MLR) and poke weed mitogen (PWM) was 0.35, 1.6, 0.8 and 5.4 mu g/ml, respectively. In addition, BS significantly inhibited the production of cytokines such as interleukin (IL)-1 beta, IL-2, interferon (IFN)-gamma and tumor necrosis factor (TWF)-alpha, by peripheral blood mononuclear cells (PBMNC) and soluble IL-2 receptor expression at concentrations greater than 1 mu g/ml. Inhibition of PHA stimulated PBMNC proliferation and IL-2 and sIL-2R production by BS indicates that it is a T-cell specific immunosuppressant. However, BS also moderately inhibited immunoglobulin (Ig) G and M at concentrations greater than 1 mu g/ml suggesting that it also has B cell immunosuppressive effects. YS was 10% less active than BS in all assay systems. In contrast, GS exhibited both suppression and enhancement of PBMNC proliferation in the presence of various stimulants. However, GS inhibited PWM stimulated PBMNC proliferation and IL-4 and IgG and IgM production at concentrations above 1 mu g/ml. All three fungal compounds altered the percentage of T-lymphocyte subpopulations only at high concentrations. Cell viability was not affected at the immunosuppressive concentrations of these compounds. In conclusion, work from our laboratory has identified three potentially potent immunomodulatory compounds from P. leucothes. These compounds have variable effects on T- and B-cells and monocytes. They may partially explain the imimmosuppressive activity of T. wilfordii. In addition, they may represent a new source of immumomodulatory compounds for the treatment of human immune mediated diseases

Biodiversity and tissue-recurrence of endophytic fungi in Tripterygium wilfordii

A total of 343 endophytic fungal isolates representing 60 taxa including 30 morphotypes were isolated from the different parts of the Chinese medicinal plant, Tripterygium wilfordii. In most cases fungal strains were only identified to genus because species identification was difficult in these speciose genera. Non-sporulating isolates were designated as Morphotypes 1 to 30. The endophytic assemblages of T. wilfordii comprised a number of cosmopolitan species such as Colletotrichum gloeosporioides, Guignardia sp., Glomerella cingulata, Pestalotiopsis spp., Phomopsis spp. and Phyllosticta sp. The overall fungal community of T. wilfordii was moderately diverse. The fungal community from the twig xylem parts was most diverse, followed by leaves, twig bark, root xylem and flowers. Pestalotiopsis cruenta, Phomopsis sp. B and Phomopsis sp. A were predominantly isolated from the twig xylem and bark. These endophytes were not isolated from the roots, leaves and flowers. Likewise, Glomerella cingulata and Guignardia sp. were predominantly isolated in leaves. Phialophora sp. was isolated only in root xylem. In contrast, Pestalotiopsis disseminata was isolated from all the tissues except root bark. Morphotype sp. 1 was isolated from twig and root segments. Interestingly, root bark only accommodated Morphotype sp. 1 and no other endophytic fungi were isolated from the organ. Pestalotiopsis spp. were frequently isolated as root endophytes in this study. The species composition and frequency of endophyte species was found to be dependent on the tissue type. The dominant fungi isolated from the different tissues of the host expressed a fair degree of tissue-recurrence.link_to_OA_fulltex

In vitro studies of endophytic fungi from Tripterygium wilfordii with anti-proliferative activity on human peripheral blood mononuclear cells

An array of endophytic fungi which habitat in a Chinese medicinal plant, Tripterygium wilfordii Hook. f., (TWHf) were isolated and tested for their suppressive activity on phytohemaglutinin (PHA) stimulated proliferation of human peripheral blood mononuclear cells (PBMC). Out of the 343 isolates, representing 60 different morphotypes, were screened. Amongst the screened fungi, only 15 isolates showed anti-proliferative activity. Ethyl acetate extracts of Pestalotiopsis leucothës, Mucor sp. Verticillium sp. or Pestalotiopsis disseminata, in particular, significantly inhibited the proliferation at doses between 0.12 and 500 μg/ml (stimulation index (S.I.) ranges 0.01-0.70) (P < 0.001-0.05). IC 50 values of these four fungal extracts were between 0.75-0.80 ± 0.12 μg/ml. Trypan blue exclusion test and visual examination of cell morphology demonstrate that the anti-proliferative effect of these extracts was not a sequential consequence of their cytotoxicity. Nevertheless, fungal extracts of Acremonium sp. A and C, Pestalotiopsis suffocata, Morphotype sp. 4 and 5 show a much higher cytotoxic effects on PBMC. Our results indicate that some fungal extracts contain significant amount of immunomodulatory principles. © 2004 Elsevier Ireland Ltd. All rights reserved.link_to_subscribed_fulltex

Immunomodulatory compounds from Pestalotiopsis leucothës, an endophytic fungus from Tripterygium wilfordii

The immunomodulatory effects of three compounds designated BS, GS, and YS produced by Pestalotiopsis leucothës, an endophytic fungus isolated from Tripterygium wilfordii, were evaluated. The 50% inhibition concentration (IC50) value of BS in the proliferative assay with various stimulating agents such as phytohemagglutinin-M (PHA-M), phorbol myristate acetate (PMA)/ionomycin, mixed lymphocyte reaction (MLR) and poke weed mitogen (PWM) was 0.35, 1.6, 0.8 and 5.4 μg/ml, respectively. In addition, BS significantly inhibited the production of cytokines such as interleukin (IL)-1β, IL-2, interferon (IFN)-γ and tumor necrosis factor (TNF)-α, by peripheral blood mononuclear cells (PBMNC) and soluble IL-2 receptor expression at concentrations greater than 1 μg/ml. Inhibition of PHA stimulated PBMNC proliferation and IL-2 and sIL-2R production by BS indicates that it is a T-cell specific immunosuppressant. However, BS also moderately inhibited immunoglobulin (Ig) G and M at concentrations greater than 1 μg/ml suggesting that it also has B cell immunosuppressive effects. YS was 10% less active than BS in all assay systems. In contrast, GS exhibited both suppression and enhancement of PBMNC proliferation in the presence of various stimulants. However, GS inhibited PWM stimulated PBMNC proliferation and IL-4 and IgG and IgM production at concentrations above 1 μg/ml. All three fungal compounds altered the percentage of T-lymphocyte subpopulations only at high concentrations. Cell viability was not affected at the immunosuppressive concentrations of these compounds. In conclusion, work from our laboratory has identified three potentially potent immunomodulatory compounds from P. leucothës. These compounds have variable effects on T- and B-cells and monocytes. They may partially explain the immunosuppressive activity of T. wilfordii. In addition, they may represent a new source of immunomodulatory compounds for the treatment of human immune mediated diseases. © 2005 Elsevier Inc. All rights reserved.link_to_subscribed_fulltex