Jittra Piapukiew

Endophytic fungi from mangrove plant species of Thailand: their antimicrobial and anticancer potentials

Abstract We examined the distribution of endophytic fungi in the leaves of mangrove forest trees growing at three different locations (Chanthaburi Province, Prachuap Khiri Khan Province and Ranong Province) in Thailand. Three thousand and nine-hundred leaf segments from 10 different hosts belonging to seven families, Rhizophoraceae (Rhizophora apiculata, R. mucronata, Ceriops decandra), Sonneratiaceae (Sonneratia alba), Combretaceae (Lumnitzera littorea), Avicenniaceae (Avicennia alba), Acanthaceae (Acanthus ilicifolius), Meliaceae (Xylocarpus granatum and Xylocarpus moluccensis) and Malvaceae (Thespesia populneoides), were screened for the presence of fungal endophytes. The dominant endophytes varied by host type. Phyllosticta was the most frequently isolated fungus from plants at all sites. The common fungal endophyte genera were Cladosporium, Colletotrichum, Phomopsis and Xylaria. Most endophytic isolates in mangrove leaves were recovered from Ranong Province. The antimicrobial potential of 71 endophytic fungi isolated from mangrove plants towards selected bacteria (Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus) was tested using ethyl acetate extracts of fungi cultivated under static conditions. All test bacteria were inhibited by a Cladosporium sp. isolated from the leaves of T. populneoides and an endophytic Xylaria sp. 1 isolated from A. ilicifolius leaves caused considerable inhibition to Gram-positive and Gram-negative bacteria. Additionally, the crude extracts of 84 endophytic fungi were tested for anticancer activities by the MTT assay against A375 (human malignant melanoma), SW620 (human colorectal adenocarcinoma), Kato III (human gastric carcinoma), HepG2 (human liver hepatoblastoma) and Jurkat (human acute T cell leukemia). Most extracts had cytotoxicity against some cancer cell lines.

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

Four xanthones were isolated from mycelia ofEmericella variecolor, an endophytic fungus isolated from the leaves ofCroton 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).

Purification and characterization of a xylanase from the endophytic fungus Alternaria alternata isolated from the Thai medicinal plant, Croton oblongifolius Roxb.

1 Biotechnology Program, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand. 2 Department of Microbiology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand. 3 Department of Botany, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand. 4 Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand. 5 Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand.

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-16β,17-dihydroxy-kauran-19-oic acid (2) was isolated. After further incubation for nine days, two novel metabolites, ent-12α,16β,17-trihydroxy-kauran-19-oic acid (3) and ent-11α,16β,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.

An extracellular lipase from the endophytic fungi Fusarium oxysporum isolated from the Thai medicinal plant, Croton oblongifolius Roxb.

From 65 endophytic fungal isolates, ten were found to produce extracellular lipase activity, with Fusarium oxysporum isolate PTM7, isolated from the leaves of Croton oblongifolius Roxb. (Plao yai), yielding the highest level. The lipase activity in the basal culture medium of PTM7 was highest with 1% (v/v) olive oil, 1% (w/v) peptone and 0.5% (w/v) sodium nitrate as the carbon, organic and inorganic nitrogen sources, respectively. A 37.4 kDa lipase was enriched with 41.4-fold to apparent homogeneity from PTM7 culture media using 80% saturation ammonium sulfate precipitation, DEAE-cellulose anion exchange and Superdex-75 gel filtration chromatography, but at a final yield of only 2.21%. The enriched lipase showed optimal activity at pH 8 and 30 o

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.

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.

First Record of Viridothelium virens (Trypetheliales, Ascomycota) in the Southeast Asian Tropics

Abstract: Luangsuphabool, T., Piapukiew, J., Lumbsch, H. T. & Sangvichien, E. 2017. First record of Viridothelium virens (Trypetheliales, Ascomycota) in the Southeast Asian tropics. — Herzogia 30: 317–321. Viridothelium virens was found growing on tree bark at 1500 m altitude in an oak forest in northern Thailand. Phenotypical and molecular data (mtSSU and nuLSU rDNA sequences) supported the identification of the sample as V. virens. This is a new record for Thailand and extends the distributional range from temperate regions (North America and Japan) to the tropics.

Community structure and dynamics of ectomycorrhizal fungi in a dipterocarp forest fragment and plantation in Thailand

Background: Ectomycorrhizal (EcM) associations have been reported with trees of the plant family Dipterocarpaceae. We hypothesised that a dipterocarp forest fragment, with more host species, would yield a higher diversity of associated EcM fungal species than that of a Dipterocarpus alatus monoculture plantation. Aims: To examine the above- and below-ground EcM community structure of a dry dipterocarp forest fragment and a D. alatus plantation in Thailand. Methods: Sporocarps were collected and identified, and EcM root tips were collected in the dry and wet seasons and identified by terminal restriction fragment length polymorphism and internal transcribed spacer sequencing. Results: Higher EcM fungal diversity was observed in the dry dipterocarp forest fragment than in the D. alatus plantation, with a larger number of species found in the wet seasons than the dry seasons. Sporocarp species richness was greater than root-tip EcM richness. Different dominant EcM taxa were observed in the above- and below-ground communities. Conclusions: Our results suggest that host tree diversity may explain the greater EcM fungal diversity in the dry dipterocarp forest fragment than the D. alatus monoculture plantation. Seasonal dynamics also influences the composition of the EcM communities, with different dominant taxa and relative abundance in the dry and wet seasons. Further research would be of great help in providing useful information for management of dipterocarp forests as well as restoration of disturbed landscapes.

Genetic analysis of physic nut Jatropha curcas L. populations in Thailand using ISSR markers

Jatropha curcas L. (Physic nut) is a drought-resistant shrub belonged to the family Euphorbiaceae. The oil from most J. curcas varieties has a low viscosity that makes it an attractive alternative energy source for biofuel production. Evaluating the degree of genetic diversity between populations and the development of genome wide markers are important for the long-term improvement of cultured varieties in any given habitat. The genetic diversity of 58 samples from 13 J. curcas populations, and one outgroup of J. gossypifolia, in Thailand were analyzed by inter-simple sequence repeat (ISSR). From 12 screened ISSR primers, two primers ((AG)8 T and (ATG)5) generated a total of 21 discrete and reliably amplified products, of which 15 were polymorphic and revealed 71.4% polymorphism among the tested J. curcas in Thailand. An UPGMA dendrogram of the Thai J. curcas samples, based on their genetic similarity using these dominant ISSR markers, divided the 13 populations into at least six main groups, with two being further divided into at least two subgroups each, which were largely incongruent with their geographical locations. It is possible that the genetic variation within J. curcas, which is widely distributed throughout Thailand since its initial introduction, is caused by human disturbance.