Candida easanensis sp. nov., Candida pattaniensis sp. nov. and Candida nakhonratchasimensis sp. nov., three new species of yeasts isolated from insect frass in Thailand

Six strains of anamorphic yeasts isolated from insect frass collected in several regions of Thailand were assigned to the genus Candida based on the conventional taxonomic criteria used for yeast classification. These strains have Q-7 as the major ubiquinone and are suggested to have close relationships to the genus Pichia. Three strains, ST-225, ST-228 and ST-229, have identical nucleotide sequences in the D1/D2 domain of 26S rDNA and are closely related to Pichia japonica, but differ by six nucleotides (1.1% ) from this species. These three strains are considered to represent a single new species, which is described as Candida easanensis sp. nov. Two strains, ST-311 and ST-320, have identical sequences in the D1/D2 domain and resemble Pichia veronae and Pichia fabianii but differ from them by nine nucleotides (1.6%) in D1/D2 sequences. The two strains are described as Candida pattaniensis sp. nov. The remaining strain, ST-37, is related to Pichia americana and Pichia bimundalis but differs by six(1.1%) and seven (1.2%) nucleotides from these species, respectively. This strain is described as Candida nakhonratchasimensis sp. nov.     

A New Yeast Species,Candida aurita sp. nov., from Oligotrophic Bogs of Western Siberia

Five anamorphous yeast strains of ascomycetous affinity with a specific mode of budding were isolated from high bog soils of the Bakcharskoe Bog (Tomsk oblast). According to their morphological and physiological properties, these strains belong to the genus Candida but differ from all species described previously. The level of DNA–DNA homology with species similar in the assimilation spectrum was as low as 7%. Based on these data, the new species Candida aurita sp. nov. is described.     

Three new thermotolerant methylotrophic yeasts, Candida krabiensis sp. nov., Candida sithepensis sp. nov., and Pichia siamensis sp. nov., isolated in Thailand

Five strains of thermotolerant methylotrophic yeasts isolated in Thailand were found to represent three new species in the genera Pichia and Candida, based on phylogenetic analysis of D1/D2 domain of 26S rDNA, in addition to the morphological, physiological, biochemical and chemotaxonomic characterization. Three strains, FS96 and FS101 from flowers and M02 from tree flux, were characterized by ubiquinone Q7, multilateral budding, and the formation of hat-shaped ascospores that are liberated at maturation. These strains showed identical nucleotide sequences in the D1/D2 domain and formed a cluster with Candida thermophila, "Pichia salicis" and Pichia angusta. They differed by 1.9% of nucleotide substitutions from Candida thermophila, the nearest species. They were considered to represent a single new species and are described as Pichia siamensis sp. nov. Two strains, N051 and S023, isolated from soil did not produce ascospores, proliferated by multilateral budding, did not demonstrate urease or DBB color reaction, and lacked sexual stages. These characteristics correspond to the genus Candida. Strains N051 and S023 differed by 2.8% and 1.9% of nucleotide substitutions in the D1/D2 domain from the nearest species, Candida nemodendra and Candida ovalis, respectively, and are considered to represent respective new species. N051 and S023 are described as Candida krabiensis sp. nov. and Candida sithepensis sp. nov., respectively.     

Candida potacharoeniae sp. nov. and Candida spenceri sp. nov., two novel galactose-containing ascomycetous anamorphic yeast species isolated in Thailand

Fifteen strains of anamorphic yeasts isolated from various natural substrates collected in various places in Thailand were found to represent two novel species of anamorphic yeast genus Candida based on the sequence analysis of the D1/D2 domain of the large subunit rRNA genes, chemotaxonomic and conventional properties used for the classification of yeasts. These strains are located in the clade including Candida etchellsii and Candida magnoliae. Fourteen strains represented by ST-490(T) (BCC 15176(T)=NBRC 106439(T)= CBS 11674(T)) are closely related to Candida sorbosivorans in the D1/D2 sequences but 11 nucleotides (2.4%) were substituted. The remaining strain, ST-594(T) (=BCC 15278(T)=NBRC 106446(T)=CBS 11673(T)) showed a close relationship to Candida geochares but 21 nucleotides (4.7%) were substituted. Apparently, these strains represent two novel Candida species of the Starmerella clade. The two species are described as Candida potacharoeniae sp. nov. and Candida spenceri sp. nov. in the present paper. Like the most species of this clade, the two species contain galactose in the cells in addition to glucose and mannose and have high mol% G + C of 54.4-55.9 and 54.9, respectively.     

Four novel species of the anamorphic yeast genus Candida found in Thailand and Taiwan

Four strains of yeasts isolated in Thailand and Taiwan were found to represent four distinct novel species of the ascomycetous anamorphic yeast genus Candida. These strains are located in the Clavispora-Metschnikowia clade in a phylogenetic tree based on the D1/D2 domain sequences of the large subunit rRNA genes. Together with Candida picinguabensis and Candida saopaulonensis, the four novel species constitute a well-separated subclade from other species of the Clavispora-Metschnikowia clade. Three species from Thailand are described as Candida bambusicola sp. nov. (type strain, ST-50(T) = BCC 7750(T) = NBRC 106734(T) = CBS 11723(T)), Candida nongkhaiensis sp. nov. (type strain, ST-95(T) = BCC 8331(T) = NBRC 105874(T) =CBS 11724(T)) and Candida succicola sp. nov. (type strain, ST-631(T) = BCC 15314(T) = NBRC 106736(T) = CBS 11726(T)), respectively, and the species from Taiwan is described as Candida touchengensis sp. nov. (type strain, SY4S03(T) = NBRC 102647(T) = BCRC 23097(T) = CBS 10585(T)).     

Candida carvajalis sp. nov., an ascomycetous yeast species from the Ecuadorian Amazon jungle

In the course of a yeast biodiversity survey of different ecological habitats found in Ecuador, two yeast strains (CLQCA 20-011^T and CLQCA20-014) were isolated from samples of rotten wood and fallen leaf debris collected at separate sites in the central region of the Ecuadorian Amazonia. These strains were found to represent a novel yeast species based on the sequences of their D1/D2 domain of the large-subunit (LSU) rRNA gene and their physiological characteristics. Phylogenetic analysis based on LSU D1/D2 sequences revealed this novel species to be most closely related to Candida asparagi, Candida fructus, Candida musae and two as yet undescribed Candida species, with the six yeast taxa collectively forming a distinct species group within the Clavispora clade. The species name of Candida carvajalis sp. nov. is proposed to accommodate these strains, with CLQCA 20-011^T (NCYC 3509^T, CBS 11361^T) designated as the type strain.     

Use of molecular methods in identification of Candida species and evaluation of fluconazole resistance

The aim of this study was to evaluate the use of one of the molecular typing methods such as PCR (polymerase chain reaction) following by RFLP (restriction fragment length polymorphism) analysis in the identification of Candida species and then to differentiate the identified azole susceptible and resistant Candida albicans strains by using AP-PCR (arbitrarily primed-polymerase chain reaction). The identification of Candida species by PCR and RFLP analysis was based on the size and primary structural variation of rDNA intergenic spacer regions (ITS). Forty-four clinical Candida isolates comprising 5 species were included to the study. The amplification products were digested individually with 3 different restriction enzymes: HaeIII, DdeI, and BfaI. All the isolates tested yielded the expected band patterns by PCR and RFLP analysis. The results obtained from this study demonstrate that Candida species can be differentiated as C. albicans and non-C. albicans strains only by using HaeIII restriction enzyme and BfaI maintains the differentiation of these non-C. albicans species. After identification Candida species with RFLP analysis, C. albicans strains were included to the AP-PCR test. By using AP-PCR, fluconazole susceptible and resistant strains were differentiated. Nine fluconazole susceptible and 24 fluconazole resistant C. albicans were included to the study. Fluconazole resistant strains had more bands when evaluating with the agarose gel electrophoresis but there were no specific discriminatory band patterns to warrant the differentiation of the resistance. The identification of Candida species with the amplification of intergenic spacer region and RFLP analysis is a practical, short, and a reliable method when comparing to the conventional time-consuming Candida species identification methods. The fluconazole susceptibility testing with AP-PCR seems to be a promising method but further studies must be performed for more specific results.     

Three novel species of the anamorphic yeast genus Candida in the Candida intermedia clade found in Japan, Thailand and Taiwan

Four strains of yeasts isolated in Japan, Thailand and Taiwan were found to represent three novel species of the genus Candida. The three species are located in a clade including Candida tsuchiyae, Candida thailandica and Candida akabanensis in a tree based on the D1/D2 domain sequences of the large subunit rRNA genes but clearly differentiated from these relative species. Three novel species are proposed for these strains, i. e., Candida berkhoutiae sp. nov., for strains ST-49(T) (=BCC 7749(T)=NBRC 106733(T)=CBS 11722(T)) isolated from insect frass in Thailand and SA13S01 (=NBRC 106053) isolated from soil in Taiwan, Candida ezoensis sp. nov., for strain Y07-1601-2(T) (=NBRC 105019(T)=CBS 11753(T)) isolated from forest soil in Japan, and Candida inulinophila sp. nov., for ST-369(T) (=BCC 15081(T)=NBRC 106735(T)=CBS 11725(T)) isolated from an unidentified wild mushroom from Thailand.     

Candida shehatae sp. N., a yeast associated with wood-destroying insects

Summary Candida shehatae is described as a new species. The strains studied were isolated in various parts of the world from insect-invaded wood, a wood-destroying insect and soil.     

Candida kazuoi sp. nov. and Candida hasegawae sp. nov., two new species of ascomycetous anamorphic yeasts isolated from insect frass in Thailand

Two strains of anamorphic yeasts isolated from insect frass collected in southern Thailand were assigned to the genus Candida based on the conventional taxonomic criteria used for yeast classification. In the phylogenetic tree based on the D1/D2 domain of the 26S rDNA, these strains are distant from the known species of yeasts and considered to represent two different new species. They are named Candida kazuoi sp. nov. and Candida hasegawae sp. nov.     

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii. Strain YF9E(T) was most closely related to C. azyma and strain YWZH3C(T) to C. sorbophila and C. spandovensis. Strain YYF2A(T) was clustered in a clade containing small-spored Metschnikowia species and related anamorphic Candida species. The new strains differed from their closely related described species by more than 10% mismatches in the D1/D2 domain. No sexual states were observed for the four strains on various sporulation media. The new species are therefore assigned to the genus Candida and described as Candida alocasiicola sp. nov. (type strain, YF9E(T) = AS 2.3484(T) = CBS 10702(T)), Candida hainanensis sp. nov. (type strain, YYF2A(T) = AS 2.3478(T) = CBS 10696(T)), Candida heveicola sp. nov. (type strain, YJ2E(T) = AS 2.3483(T) = CBS 10701(T)) and Candida musiphila sp. nov. (type strain, YWZH3C(T) = AS 2.3479(T) = CBS 10697(T)).     

The teleomorph state of Candida deformans Langeron & Guerra and description of Yarrowia yakushimensis comb. nov.

Yarrowia lipolytica is the only known species in the teleomorph (i.e. sexual) genus Yarrowia and has its anamorph (i.e. asexual state) classified in the genus Candida Berkhout as Candida lipolytica. This species can be found readily in nature, has significant industrial value and is important to the food and medical fields. Candida deformans was first considered a variety of C. lipolytica and was later listed as a synonym of this species. More recent studies based on sequence variation in the nuclear rRNA gene sequences suggested C. deformans to be a separate species with no known teleomorph linked to it. In this study we show that C. deformans strains, obtained from South Africa, can mate with strains present in the CBS yeast collection and produce a Yarrowia teleomorph, described here as Yarrowia deformans. Strains of Candida yakushimensis nom. inval., a species also belonging to the Yarrowia phylogenetic clade, were also studied and described as a novel species of Yarrowia.     

Three new ascomycetous yeasts from insect-associated arboreal habitats

A new species of Pichia and two new species of Candida are described and were determined to be genetically isolated from all other currently recognized ascomycetous yeasts from their sequence divergence in the species-variable D1/D2 domain of large subunit (26S) ribosomal DNA. The three species were primarily isolated from the frass of wood-boring insects living in pine and spruce trees. The new species and their type strains are the following: Pichia ramenticola NRRL YB-1985 (CBS 8699), mating type alpha (NRRL YB-3835, CBS 8700, mating type a), Candida piceae NRRL YB-2107 (CBS 8701), and Candida wyomingensis NRRL YB-2152 (CBS 8703). Pichia ramenticola and C. piceae assimilate methanol as a carbon source; P. ramenticola is the first known heterothallic ascomycetous yeast to utilize this compound.     

Two new species of the genus Candida in the Zygoascus clade, Candida lundiana sp. nov. and Candida suthepensis sp. nov., isolated from raw honey in Thailand

During a survey of yeasts associated with raw honey collected in Thailand, two strains of the Zygoascus clade were isolated from the Asian cavity-nesting honeybee Apis cerana and the stingless bee Homotrigona fimbriata. Phylogeny based on 26S rDNA D1/D2 sequences placed these yeasts as members of a clade including Candida bituminiphila, Candida patagonica and Candida polysorbophila. The strains of the two novel species, CBS 12271^T and CBS 12270^T, respectively, could be unquestionably distinguished from their relatives by rDNA sequences and other taxonomic characteristics. Therefore, the novel anamorphic species, Candida lundiana sp. nov. (type strain CBS 12271^T = JCM 16823^T) and Candida suthepensis sp. nov. (type strain CBS 12270^T = JCM 16822^T) are described.     

Candida ruelliae sp. nov., a novel yeast species isolated from flowers of Ruellia sp. (Acanthaceae)

Two novel yeast strains designated as 16Q1 and 16Q3 were isolated from flowers of the Ruellia species of the Acanthaceae family. The D1/D2 domain and ITS sequences of these two strains were identical. Sequence analysis of the D1/D2 domain of large-subunit rRNA gene indicated their relationship to species of the Candida haemulonii cluster. However, they differ from C. haemulonii by 14% nucleotide sequence divergence, from Candida pseudohaemulonii by 16.1% and from C. haemulonii type II by 16.5%. These strains also differ in 18 physiological tests from the type strain of C. haemulonii, and 12 and 16 tests, respectively, from C. pseudohaemulonii and C. haemulonii type II. They also differ from C. haemulonii and other related species by more than 13% sequence divergence in the internal transcribed spacer region. In the SSU rRNA gene sequences, strain 16Q1 differs by 1.7% nucleotide divergence from C. haemulonii. Sporulation was not observed in pure or mixed cultures on several media examined. All these data support the assignment of these strains to a novel species; we have named them as Candida ruelliae sp. nov., and designate strain 16Q1(T)=MTCC 7739(T)=CBS10815(T) as type strain of the novel species.     

Two new amycelial Candida isolated from decayed wood in the evergreen rainy Valdivian forest of southern Chile

Two novel representatives of the yeast genus Candida, isolated from advanced stages of degradation from fallen trunks of Nothofagus dombeyii (Mirb.) Blume and Laurelia sempervirens Weim., in the evergreen rainy Valdivian forest of southern Chile, are described and illustrated. The strains differ from all accepted Candida species to warrant their establishment as two new species: Candida petrohuensis and Candida rancensis.     

口腔黏膜真菌鉴定方法的比较

比较常见用于黏膜真菌菌种鉴别的多种方法,探寻最佳的鉴别方法。采集230例普通人群口腔黏膜样本,分别用玉米吐温-80培养观察厚膜孢子法、糖发酵生化反应法、CHROMagar假丝酵母菌显色培养基法、ITS基因的PCR-RFLP(聚合酶链反应-限制性片段长度多态性)法、ITS测序菌种鉴定法,鉴别真菌各菌株。结果显示:有56例菌株至少通过1种方法检出真菌;玉米吐温-80分离培养假丝酵母菌37株;50例菌株ITS基因测序共鉴定出8个菌种,白假丝酵母菌(C.albicans)29株,近平滑假丝酵母菌(C.parapsilosis)10株,热带假丝酵母菌(C.tropicalis)5株,Candida metapsilosis 1株,Lodderomyces elongisporus 1株,克柔假丝酵母菌(Candida krusei)1株,乙醇假丝酵母菌(C.ethanolica)1株,季也蒙毕赤酵母菌(Pichia guilliermondii)2株;CHROMagar假丝酵母菌显色培养基法鉴定出3种菌株,分别是白假丝酵母菌、热带假丝酵母菌、近平滑假丝酵母菌;PCR-RFLP法检出5种菌株,分别是白假丝酵母菌、热带假丝酵母菌、近平滑假丝酵母菌、季也蒙毕赤酵母菌、克柔假丝酵母菌,与基因的测序鉴定一致率为91%;糖发酵生化反应法阳性标本占被检出真菌例数的46.4%(26/56)。结果表明:ITS基因的测序法可以准确鉴定真菌各个菌种;PCR-RFLP法能鉴定常见的菌种,但操作繁琐;CHROMagar假丝酵母菌显色培养基法能快速准确鉴别3种常见假丝酵母菌菌种;玉米吐温-80可以准确培养鉴别白假丝酵母菌;糖发酵生化反应法,缺乏足够的敏感度和特异性,难以准确鉴别各个菌种。