Publications by authors named "Somsak Sivichai"

6 Publications

  • Page 1 of 1

Annulatascus aquatorba sp. nov., a lignicolous freshwater ascomycete from Sirindhorn Peat Swamp Forest, Narathiwat, Thailand.

Mycologia 2012 May-Jun;104(3):746-57. Epub 2012 Jan 5.

National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand.

As part of a long term study of fungi colonizing submerged wood in freshwater streams a new Annulatascus species, A. aquatorba, is described and illustrated from Erythrophleum teysmannii test blocks from Sirindhorn Peat Swamp Forest, southern Thailand. It differs from other species in the genus in ascospore measurements, thickness of the cell wall, 1-3-septate, fusoid to lunate shape, with central brown cells and subhyaline end cells and without a mucilaginous sheath. Asci are cylindrical, pedicellate, with a distinct, wedge-shaped and non-amyloid apical ring. Phylogenetic relationships of this species, based on the combined partial 18S and 28S rDNA, place it in the same clade as A. velatisporus (type species), A. hongkongensis and A. nilensis.
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http://dx.doi.org/10.3852/11-238DOI Listing
January 2013

Savoryellales (Hypocreomycetidae, Sordariomycetes): a novel lineage of aquatic ascomycetes inferred from multiple-gene phylogenies of the genera Ascotaiwania, Ascothailandia, and Savoryella.

Mycologia 2011 Nov-Dec;103(6):1351-71. Epub 2011 Jun 3.

Mycology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Phaholyothin Road, Khlong 1, Khlong Luang, Pathumthani 12120, Thailand.

The taxonomic placement of freshwater and marine Savoryella species has been widely debated, and the genus has been tentatively assigned to various orders in the Sordariomycetes. The genus is characterized as possessing paraphyses that deliquesce early, elongate, clavate to cylindrical asci with a poorly developed apical ring and versicolored, three-septate ascospores. We performed two combined phylogenetic analyses of different genes: (i) partial small subunit rRNA (SSU), large subunit rRNA (LSU), DNA-dependent RNA polymerase II largest subunit (rpb2) dataset and (ii) SSU rDNA, LSU rDNA, DNA-dependent RNA polymerase II largest subunit (rpb1 and rpb2), translation elongation factor 1-alpha (tef1), the 5.8S ribosomal DNA (5.8S rDNA) dataset. Our results indicate that Savoryella species formed a monophyletic group within the Sordariomycetes but showed no affinity to the Hypocreales, Halosphaeriales (now Microascales), Sordariales and Xylariales, despite earlier assignments to these orders. Savoryella, Ascotaiwania and Ascothailandia (and its anamorph, Canalisporium) formed a new lineage that has invaded both marine and freshwater habitats, indicating that these genera share a common ancestor and are closely related. Because they show no clear relationship with any named order we erect a new order Savoryellales in the subclass Hypocreomycetidae, Sordariomycetes. The genera Savoryella and Ascothailandia are monophyletic, while the position of Ascotaiwania is unresolved. All three genera are phylogenetically related and form a distinct clade similar to the unclassified group of marine ascomycetes comprising the genera Swampomyces, Torpedospora and Juncigera (TBM clade: Torpedospora/Bertia/Melanospora) in the Hypocreomycetidae incertae sedis.
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http://dx.doi.org/10.3852/11-102DOI Listing
January 2012

Tubeufia asiana, the teleomorph of Aquaphila albicans in the tubeufiaceae, pleosporales, based on cultural and molecular data.

Mycologia 2007 Nov-Dec;99(6):884-94

Department of Botany, 3529-6270 University Boulevard, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.

The teleomorph of Aquaphila albicans was discovered on submerged wood collected in Thailand. Its black, soft-textured, setose ascomata, bitunicate asci and hyaline to pale brown, multiseptate ascospores indicated an affinity to Tubeufiaceae (Dothideomycetes). After morphological or molecular comparisons with related species in Tubeufia, Acanthostigma and Taphrophila, it is described and illustrated as a new species, T. asiana Sivichai & K.M. Tsui, sp. nov. Finding this Tubeufia teleomorph was surprising, given the falcate conidia of its A. albicans anamorph, which superficially resemble the conidia of Fusarium and not the coiled, helicosporous conidia of other species in Tubeufiaceae. We assessed the phylogenetic relationships of A. albicans-T. asiana with ribosomal sequences from SSU and ITS and partial LSU regions by parsimony and Bayesian analysis. An initial set of 40 taxa representing a wide range of ascomycete families and their SSU sequences from GenBank showed A. albicans-T. asiana to be nested within the Tubeufiaceae with 100% bootstrap support. Their placement was inferred with ITS and partial LSU ribosomal sequences. The nearly identical ITS sequences of two isolates of A. albicans and one isolate of Tubeufia asiana united these fungi as a monophyletic group with 100% bootstrap support and further nested them, with 88% bootstrap support, in a clade containing Helicoon gigantisporum and Helicoma chlamydosporum. This is the first molecular phylogenetic study to place a nonhelicosporous species within the Tubeufiaceae and to show that helical conidia were lost at least once within the family.
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http://dx.doi.org/10.3852/mycologia.99.6.884DOI Listing
April 2008

Megalohypha, a new genus in the Jahnulales from aquatic habitats in the tropics.

Mycologia 2007 May-Jun;99(3):456-60

Department of Plant Biology, University of Illinois, Room 265 Morrill Hall, 505 South Goodwin Avenue, Urbana, Illinois 61801, USA.

A new fungus collected from submerged wood in tropical forest streams in Panama and Thailand is described as a new genus and species in the Jahnulales. This fungus, Megalohypha aqua-dulces, is described based on ascospore morphology, which differs substantially from that of the other genera in the Jahnulales. It has these morphological features: ascomata hyaline, translucent, with subtending, wide, brown, septate, stoloniferous hyphae; peridium of large, thin-walled cells; hamathecium of septate pseudoparaphyses; asci clavate, fissitunicate, 8-spored; and ascospores 1-septate, brown, rough-walled, with longitudinal sulcate striations. An interesting feature of Megalohypha aqua-dulces, which it shares with some other taxa in Jahnulales, is the presence of both sessile and stalked fruiting bodies. In addition, the stalks have morphology that consists of a wide hypha with a narrower hypha apparently enclosed within and the stalks are strongly constricted at the septa.
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http://dx.doi.org/10.3852/mycologia.99.3.456DOI Listing
October 2007

In search of cyclooxygenase inhibitors, anti-Mycobacterium tuberculosis and anti-malarial drugs from Thai flora and microbes.

Pharmacol Ther 2007 Sep 18;115(3):307-51. Epub 2007 May 18.

King Mongkut's University of Technology Thonburi, School of Bioresources and Technology, Conservation Ecology Program, 83 Moo 8, Thakham, Bangkhuntien, Bangkok, Thailand.

Malaria continues to be a major infectious disease of the developing world and the problem is compounded not only by the emergence of drug resistant strains but also from a lack of a vaccine. The situation for tuberculosis (TB) infection is equally problematic. Once considered a "treatable" disease for which eradication was predicted, TB has re-emerged as highly lethal, multi-drug resistant strains after the outbreak of AIDS. Worldwide, the disease causes millions of deaths annually. Similarly, treatments for chronic inflammatory diseases such as arthritis have been impeded due to the potentially lethal side effects of the new and widely prescribed non-steroidal anti-inflammatory compounds. Thais have utilized bioresources from plants and some microorganisms for medicine for thousands of years. Because of the need for new drugs to fight malaria and TB, with radically different chemical structures and mode of actions other than existing drugs, efforts have been directed towards searching for new drugs from bioresources. This is also true for anti-inflammatories. Although Thailand is considered species-rich, only a small number of potential bioresources has been investigated. This article briefly describes the pathogenesis of 2 infectious diseases, malaria and TB, and modern medicines employed in chemotherapy. Diversities of Thai flora and fungi and their chemical constituents with antagonistic properties against these 2 diseases are described in detail. Similarly, anti-inflammatory compounds, mostly cyclooxygenase (COX) inhibitors, are also described herein to demonstrate the potential of Thai bioresources to provide a wide array of compounds for treatment of diseases of a different nature.
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http://dx.doi.org/10.1016/j.pharmthera.2007.03.016DOI Listing
September 2007

Molecular systematics of Helicoma, Helicomyces and Helicosporium and their teleomorphs inferred from rDNA sequences.

Mycologia 2006 Jan-Feb;98(1):94-104

Department of Botany, University of British Columbia, Vancouver, Canada.

Three genera of asexual, helical-spored fungi, Helicoma, Helicomyces and Helicosporium traditionally have been differentiated by the morphology of their conidia and conidiophores. In this paper we assessed their phylogenetic relationships from ribosomal sequences from ITS, 5.8S and partial LSU regions using maximum parsimony, maximum likelihood and Bayesian analysis. Forty-five isolates from the three genera were closely related and were within the teleomorphic genus Tubeufia sensu Barr (Tubeufiaceae, Ascomycota). Most of the species could be placed in one of the seven clades that each received 78% or greater bootstrap support. However none of the anamorphic genera were monophyletic and all but one of the clades contained species from more than one genus. The 15 isolates of Helicoma were scattered through the phylogeny and appeared in five of the clades. None of the four sections within the genus were monophyletic, although species from Helicoma sect. helicoma were concentrated in Clade A. The Helicosporium species also appeared in five clades. The four Helicomyces species were distributed among three clades. Most of the clades supported by sequence data lacked unifying morphological characters. Traditional characters such as the thickness of the conidial filament and whether conidiophores were conspicuous or reduced proved to be poor predictors of phylogenetic relationships. However some combinations of characters including conidium colour and the presence of lateral, tooth-like conidiogenous cells did appear to be predictive of genetic relationships.
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http://dx.doi.org/10.3852/mycologia.98.1.94DOI Listing
August 2006