The study aimed to investigate yeast communities in sugarcane (
Saccharum officinarum
Linn.) phylloplane in Thailand by a culture-dependent approach using a direct isolation method; namely, plating ...of leaf washing for yeast isolation. A total of 150 yeast strains were obtained from 79 sugarcane leaf samples collected in ten provinces. Identification on the basis of the D1/D2 region of the large subunit (LSU) rRNA gene sequence analysis revealed that 126 yeast strains (84%) were identified to be yeast in the phylum
Basidiomycota
and 24 strains (16%) were in the phylum
Ascomycota
. Basidiomycetous yeast consisted of 27 known species in 18 genera viz.
Cystobasidium
,
Dioszegia
,
Dirkmeia
,
Hannaella
,
Jaminaea
,
Kwoniella
,
Langdonia
,
Moesziomyces
,
Occultifur
,
Papiliotrema
,
Piskurozyma
,
Pseudozyma
,
Rhodosporidiobolus
,
Rhodotorula
,
Saitozyma
,
Sporobolomyces
,
Symmetrospora
and
Tremella,
whereas, ascomycetous yeast consisted of three species viz.
Candida parapsilosis
,
Kodamaea ohmeri
and
Meyerozyma caribbica
. In addition, the most common known yeast species detected were
Dirkmeia churashimaensis
with relative frequency and frequency of occurrence of 12.0 and 22.8%, respectively. Subsequently, seven strains were found to be five new yeast species, which were already proposed as
Kalmanozyma vetiver
,
Wickerhamiella siamensis
,
Papiliotrema siamense
,
Hannaella phyllophila
and
Occultifur tropicalis
. The results of this study revealed a higher number of yeast strains and species in the phylum
Basidiomycota
, which agreed with other reports. However, the present results are opposite to those of our previous study when the enrichment technique was used for yeast isolation.
1 Department of Microbiology, Faculty of Science, Kasetsart University, 50 Paholyothin Road, Bangkok 10900, Thailand
2 The International Center for Biotechnology, Osaka University, 2-1 Yamada-oka, ...Suita-City, Osaka 565-0871, Japan
3 NITE Biological Resource Center (NBRC), Department of Biotechnology, National Institute of Technology and Evaluation, 2-5-8 Kazusakamatari, Kisarazu-City, Chiba 292-0818, Japan
Correspondence Savitree Limtong fscistl{at}ku.ac.th
Two yeast strains (TM2-16 and PT1-17 T ) were isolated by membrane filtration from samples of estuarine water collected from two mangrove forests, in Khao Lumpee-Haad Thaimueang National Park and Mu Ko Ra-Ko Prathong National Park, Phang-Nga Province, Thailand. Analysis of the D1/D2 domain of the large-subunit rDNA sequences revealed that the sequences of the two strains were identical. The closest species in terms of pairwise sequence similarity was Candida galli , but the level of nucleotide substitutions (13.2 %) was sufficient to justify the description of a separate species. Phylogenetic analysis demonstrated that the two strains occupy a basal position with respect to Yarrowia lipolytica and C . galli of the Yarrowia clade, supported by a high bootstrap value. The two strains showed identical phenotypic characteristics, including proliferation by multilateral budding, absence of ascospores and ballistoconidia and negative Diazonium blue B and urease reactions. The major ubiquinone was Q-9. On the basis of the above findings, these two strains were assigned to a single novel species of the genus Candida , for which the name Candida phangngensis sp. nov. is proposed. The type strain is PT1-17 T (=BCC 21231 T =NBRC 101967 T =CBS 10407 T ).
Abbreviations: LSU, large subunit; SSU, small subunit
The GenBank/EMBL/DDBJ accession numbers for the sequences of the D1/D2 domain of the LSU rDNA of strains TM2-16 and PT1-17 T are AB304771 and AB304772 .
1 Department of Microbiology, Faculty of Science, Kasetsart University, 50 Paholyothin Road, Bangkok 10900, Thailand
2 Laboratory of Microbial Biotechnology, Division of Applied Life Sciences, ...Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
3 NITE Biological Resource Center, Department of Biotechnology, National Institute of Technology and Evaluation, 2-5-8 Kazusakamatari, Kisarazu, Chiba 292-0818, Japan
Correspondence Savitree Limtong fscistl{at}ku.ac.th
Two thermotolerant, methylotrophic yeast strains, PT44 T and S051 T , were respectively isolated from a tree exudate and soil collected in Thailand. They were categorized as thermotolerant strains on the basis of their good growth below 20 °C and up to a relatively high temperature (37 °C). The major characteristics of the two strains that place them in the genus Ogataea are the formation of four helmet- or hat-shaped ascospores in a deliquescent ascus that may be produced parthenogenetically or by conjugation between a cell and its bud or between independent cells; multilateral budding; assimilation of nitrate; the presence of ubiquinone Q7; negative for Diazonium blue B colour and urease reactions; and the absence of arthroconidia and ballistoconidia. Analysis of the D1/D2 domains of the large-subunit rDNA sequence revealed that strain PT44 T was differentiated from the strain S051 T by 25 nucleotide substitutions and 1 gap in 554 nt, which was sufficient to justify the description of two separate species. The closest recognized species in terms of pairwise sequences similarity to PT44 T was Pichia ( Ogataea ) dorogensis , with 13 nucleotide substitutions and 1 gap in 554 nt. Strain S051 T was closest to Pichia thermomethanolica , with 7 nucleotide substitutions in 566 nt. Phenotypic characteristics of strains PT44 T and S051 T allowed them to be differentiated from each other and from the closest related species. On the basis of the above finding, the two strains represent two novel species of the genus Ogataea , for which the names Ogataea chonburiensis sp. nov. (type strain PT44 T =BCC 21227 T =NBRC 101965 T =CBS 10363 T ) and Ogataea nakhonphanomensis sp. nov. (type strain S051 T =BCC 21228 T =NBRC 101966 T =CBS 10362 T ) are proposed. We also propose the transfer of two thermotolerant methylotrophic members of the genus Pichia described previously to the genus Ogataea : Pichia siamensis is renamed Ogataea siamensis (Limtong, Srisuk, Yongmanitchai, Kawasaki, Yurimoto, Nakase & Kato) Limtong, Srisuk, Yongmanitchai, Yurimoto & Nakase comb. nov. (type strain JCM 12264 T =TISTR 5818 T ) and Pichia thermomethanolica is renamed Ogataea thermomethanolica (Limtong, Srisuk, Yongmanitchai, Yurimoto, Nakase & Kato) Limtong, Srisuk, Yongmanitchai, Yurimoto & Nakase comb. nov. (type strain CBS 10098 T =JCM 12984 T =BCC 16875 T ).
The GenBank/EMBL/DDBJ accession numbers for the sequences of the D1/D2 domain of the 26S rDNA of strains PT44 T and S051 T are respectively AB307721 and AB307722 .
1 Departamento de Microbiologia, ICB, CP 486, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
2 BIOTEC Culture Collection, National Center for Genetic Engineering and ...Biotechnology (BIOTEC), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
3 Department of Microbiology, Faculty of Science, Kasetsart University, 50 Paholyothin Road, Bangkok 10900, Thailand
4 NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation, 2-5-8 Kazusakamatari, Kisaraza, Chiba 292-0818, Japan
5 Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
6 Instituto de Ecología y Sistemática (IES), Carretera de Varona, km 3 Capdevila, Boyeros, AP8029 CP 10800, Ciudad de la Habana, Cuba
7 Mycothèque de l'Université catholique de Louvain (MUCL), Member of the Belgian Coordinated Collection of Microorganisms (BCCM TM ), Croix du Sud 3, bte 6, 1348 Louvain la-Neuve, Belgium
8 Departamento de Bioquímica e Microbiologia, Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Avenida 24A, 1515 Rio Claro, SP 13506-900, Brazil
9 Centro de Recursos Microbiológicos (CREM), Biotechnology Unit, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
10 Laboratório de Microbiologia Ambiental e Biologia, Campus Universitário de Palmas, Fundação Universidade Federal do Tocantins, Palmas, Tocantins 77010-154, Brazil
Correspondence Carlos A. Rosa carlrosa{at}icb.ufmg.br
Analyses of nucleotide sequences from the D1/D2 domains of the large-subunit rDNA and phenotypic characteristics showed that the genera Moniliella and Trichosporonoides are members of a single, monophyletic clade that would be best represented by a single anamorphic genus. On the basis of taxonomic priority, we propose the transfer of the five species of the genus Trichosporonoides to the genus Moniliella . The description of the genus Moniliella is emended and the following new combinations are proposed: Moniliella madida comb. nov., Moniliella megachiliensis comb. nov., Moniliella nigrescens comb. nov., Moniliella oedocephalis comb. nov. and Moniliella spathulata comb. nov. In addition, ten strains representing a novel yeast species belonging to the Moniliella clade were isolated from flowers in Thailand, Cuba and Brazil. Analysis of the internal transcribed spacer and D1/D2 large-subunit rDNA sequences indicated that the isolates represent a single species that was distinct from other species of the Moniliella clade. The name Moniliella fonsecae sp. nov. is proposed to accommodate these strains. The type strain is BCC 7726 T (=CBS 10551 T ).
Abbreviations: ITS, internal transcribed spacer; LSU, large subunit
The GenBank/EMBL/DDBJ accession numbers for the sequences reported in this paper are DQ400366 , AM947064 , EF137915 , EU252153 and EU545185 .
The subphylum Saccharomycotina is a lineage in the fungal phylum Ascomycota that exhibits levels of genomic diversity similar to those of plants and animals. The Saccharomycotina consist of more than ...1 200 known species currently divided into 16 families, one order, and one class. Species in this subphylum are ecologically and metabolically diverse and include important opportunistic human pathogens, as well as species important in biotechnological applications. Many traits of biotechnological interest are found in closely related species and often restricted to single phylogenetic clades. However, the biotechnological potential of most yeast species remains unexplored. Although the subphylum Saccharomycotina has much higher rates of genome sequence evolution than its sister subphylum, Pezizomycotina , it contains only one class compared to the 16 classes in Pezizomycotina . The third subphylum of Ascomycota , the Taphrinomycotina , consists of six classes and has approximately 10 times fewer species than the Saccharomycotina . These data indicate that the current classification of all these yeasts into a single class and a single order is an underappreciation of their diversity. Our previous genome-scale phylogenetic analyses showed that the Saccharomycotina contains 12 major and robustly supported phylogenetic clades; seven of these are current families ( Lipomycetaceae , Trigonopsidaceae , Alloascoideaceae , Pichiaceae , Phaffomycetaceae , Saccharomycodaceae , and Saccharomycetaceae ), one comprises two current families ( Dipodascaceae and Trichomonascaceae ), one represents the genus Sporopachydermia , and three represent lineages that differ in their translation of the CUG codon (CUG-Ala, CUG-Ser1, and CUG-Ser2). Using these analyses in combination with relative evolutionary divergence and genome content analyses, we propose an updated classification for the Saccharomycotina , including seven classes and 12 orders that can be diagnosed by genome content. This updated classification is consistent with the high levels of genomic diversity within this subphylum and is necessary to make the higher rank classification of the Saccharomycotina more comparable to that of other fungi, as well as to communicate efficiently on lineages that are not yet formally named.
An alginate-loofa matrix was developed as a cell carrier for ethanol fermentation owing to its porous structure and strong fibrous nature. The matrix was effective for cell immobilization and had ...good mechanical strength and stability for long-term use. After a storage period of 4 months, yeast cells remained firmly immobilized and active.
The function of mitochondrial Adh3 in the thermotolerant yeast Kluyveromyces marxianus was investigated. An ADH3-disrupted mutant exhibited growth retardation on non-fermentable carbon sources, ...except for ethanol, and this was suppressed by supplementation with antioxidants. Detailed analysis of the phenotype revealed that the mutant showed an increase in the activity of NADH dehydrogenase, sensitivity to H
2
O
2
, and accumulation of reactive oxygen species (ROS), and that these carbon sources increased the activity of succinate dehydrogenase. The increase in both activities may reflect enhanced expression of both dehydrogenases by elevation of their substrate levels. The ROS level became low when antioxidants were added. These findings suggest that the ADH3 mutation and such carbon sources cause an elevation of the substrate level of the respiratory chain and eventually of the ROS level via increased expression of primary dehydrogenases, which in turn causes cell growth retardation. Adh3 might thus play a crucial role in the control of the NADH/NAD
+
balance in mitochondria.
Four genes encoding alcohol dehydrogenase (Adh) isozymes in the thermotolerant yeast Kluyveromyces marxianus, a potent candidate for ethanol production at high temperatures, were investigated. Of ...these, KmADH3 and KmADH4 were cloned and sequenced, and their deduced amino acid sequences were compared with those of KmAdh1 and KmAdh2 and other Adhs of Kluyveromyces lactis and Saccharomyces cerevisiae. The four KmAdhs had high sequence similarity, though KmAdh3 and KmAdh4 possessed an amino-terminal extension as a mitochondrial targeting sequence, and appear to belong to the zinc-containing Adh family. These results and the results of Southern blot experiments suggest that there are at least four Adh isozymes in K. marxianus, two cytoplasmic enzymes and two mitochondrial enzymes. The expression profile revealed that KmADH genes are differently expressed depending on growth phase and carbon source, suggesting that these highly homologous Adhs play distinctive roles in cells.
1 Department of Microbiology, Faculty of Science, Kasetsart University, 50 Paholyothin Road, Bangkok 10900, Thailand
2 Laboratory of Microbial Biotechnology, Division of Applied Life Sciences, ...Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
3 Central Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), NSTDA, Pathumthani 12120, Thailand
Correspondence Savitree Limtong fscistl{at}ku.ac.th
Three strains (N002, N069 and PT31 T ) of a novel thermotolerant methylotrophic yeast species belonging to the genus Pichia were isolated from soil collected in Thailand by three consecutive enrichments in methanol broth at room temperature. They were categorized as thermotolerant strains on the basis of their good growth below 20 °C and up to a high temperature (37 °C). The major characteristics of the three strains included the following and placed them in the genus Pichia : the formation of four helmet-/hat-shaped ascospores in a deliquescent ascus that might be unconjugated or produced by conjugation between a cell and its bud or between independent cells; multilateral budding; the presence of ubiquinone Q-7; negative for Diazonium blue B colour and urease reactions; and the absence of arthrospores and ballistospores. The three strains differed by one to three nucleotide substitutions in the sequences of the D1/D2 domain of the large-subunit rDNA sequence. Phylogenetic analysis revealed that their closest species was Pichia dorogensis , but with 1113 nucleotide substitutions in 554 nt. The phenotypic characteristics of the three strains were the same. The strains could be distinguished from P. dorogensis by a number of phenotypic characteristics. On the basis of the above findings, these three strains were assigned to a single novel species of Pichia , for which the name Pichia thermomethanolica sp. nov. is proposed. The type strain is PT31 T (=BCC 16875 T =JCM 12984 T =CBS 10098 T ).
Published online ahead of print on 3 June 2005 as DOI 10.1099/ijs.0.63712-0.
The GenBank/EMBL/DDBJ accession number for the sequence of the D1/D2 domain of the 26S rDNA of P. thermomethanolica sp. nov. PT31 T is AB200285 .
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