[Show abstract][Hide abstract] ABSTRACT: The circumscription of mycelial genera among the ascomycetous yeasts has been controversial because of widely different interpretations of the taxonomic significance of their phenotypic characters. Relationships among species assigned to mycelial genera were determined from extent of divergence in a ca. 600-nucleotide region near the 5′ end of the large subunit (26S) ribosomal DNA gene. Phylogenetic analyses showed that Stephanoascus is distinct from Zygoascus and that Blastobotrys, Sympodiomyces, and Arxula represent anamorphs of the Stephanoascus clade. The analyses demonstrated the following teleomorphic taxa to be congeneric: Ambrosiozyma/Hormoascus, Saccharomycopsis/Guilliermondella/Botryoascus/Arthroascus, Dipodascus/Galactomyces, and Eremothecium/Ashbya/Nematospora/Holleya. Species assigned to Dipodascus comprise two separate clades. New taxonomic combinations are proposed that reflect the phylogenetic relationships determined. Key words: mycelial yeasts, ribosomal rRNA/rDNA, molecular systematics.
[Show abstract][Hide abstract] ABSTRACT: Resident fruit microflora has been the source of biocontrol agents for the control of postharvest decay of fruits and the active ingredient in commercialized biocontrol products. With the exception of grapes and apples, information on the resident microflora of other fruits is only fragmentary, but greater knowledge in this area can be very helpful in developing biocontrol strategies. We characterized the yeast microflora of nectarines ('Croce del Sud') from the early stages of fruit development until harvest. The fruit samples were collected from trees in an unmanaged orchard. The resident fruit microflora was separated from the occasionally deposited microorganisms by discarding initial fruit washings before the final wash, followed by sonication and plating on NYDA medium. The isolated yeasts were identified by BIOLOG and by sequencing the D1/D2 domain of a large subunit of the rRNA gene and, where available, the ITS sequence. BIOLOG identified 19 and the genetic analysis 23 species of yeasts. Although the identification by these two systems was not always the same, the predominant yeasts were Rhodotorula spp., Sporodiobolus spp., Cryptococcus spp., Pichia spp., Candida spp. and yeast-like Aureobasidium pullulans. Several of the taxa appear to represent new species. The preliminary biocontrol tests against brown rot of nectarine fruit caused by Monilinia fructicola indicates significant decay control potential of some of the identified yeast species, namely Cryptococcus magnus, Cryptococcus sp. nov., Sporidiobolus pararoseus, A. pullulans and Rhodotorula sp. nov.
[Show abstract][Hide abstract] ABSTRACT: Renewable lignocellulosic materials are attractive low-cost feedstocks for bioethanol production. Furfural and 5-hydroxymethylfurfural (HMF) are among the most potent inhibitory compounds generated from acid hydrolysis of lignocelluloses to simple sugars for fermentation. In Saccharomyces cerevisiae ATCC 211239 and NRRL Y-12632 and Pichia stipitis NRRL Y-7124, furfural and HMF inhibition were determined to be dose-dependent at concentrations from 10 to 120 mM. The yeast strains were more sensitive to inhibition by furfural than HMF at the same concentration, while combined treatment of furfural and HMF synergistically suppressed cell growth. A metabolite transformed from HMF by strain NRRL Y-12632 was isolated from the culture supernatant, and conclusively identified as 2,5-bis-hydroxymethylfuran, a previously postulated HMF alcohol, with a composition of C6H8O3 and a molecular weight of 128. It is proposed that, in the presence of HMF, the yeast reduces the aldehyde group on the furan ring of HMF into an alcohol, in a similar manner as for furfural. The accumulation of this biotransformed metabolite may be less toxic to yeast cultures than HMF, as evidenced by the rapid yeast fermentation and growth rates associated with HMF conversion. The ability of yeasts to adapt to and transform furfural and HMF offers the potential for in situ detoxification of these inhibitors and suggests a genetic basis for further development of highly tolerant strains for biofuel production.
Journal of Industrial Microbiology and Biotechnology 10/2004; 31(8):345-52. · 2.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Three new anamorphic ascomycetous yeasts are described: Candida anglica (type strain NRRL Y-27079, CBS 4262), Candida cidri (type strain NRRL Y-27078, CBS 4241), and Candida pomicola (type strain NRRL Y-27083, CBS 4242). These three species were isolated from cider produced in the United Kingdom, and their identification was determined from unique nucleotide sequences in the species-specific D1/D2 domain of large subunit (26S) ribosomal DNA. Phylogenetic analysis of D1/D2 sequences placed C. anglica near Candida fragi, C. cidri near Pichia capsulata, and C. pomicola in the Pichia holstii clade.
Antonie van Leeuwenhoek 01/2002; 80(3-4):237-44. · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Six new species of the yeast genus Candida are described from their unique nucleotide sequences in the D1/D2 domain of 26S rDNA. Five of these species form a clade with Candida tanzawaensis, and the sixth is basal to this group. The new species and their sources of isolation are the following: Candida ambrosiae (type strain NRRL YB-1316, CBS 8844), from insect frass, rotted wood and mushroom fruiting bodies; Candida canberraensis (type strain NRRL YB-2417, CBS 8846), from soil; Candida caryicola (type strain NRRL YB-1499, CBS 8847), from a pignut hickory tree; Candida prunicola (type strain NRRL YB-869, CBS 8848), from exuded gum of a black cherry tree; Candida pyralidae (type strain NRRL Y-27085, CBS 5035), from insect frass; Candida xylopsoci (type strain NRRL Y-27066, CBS 6037), from insect frass.
FEMS Yeast Research 01/2002; 1(3):177-85. · 2.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A new ascosporic yeast, Metschnikowia fructicola (type strain NRRL Y-27328, CBS 8853), is described and was isolated from grapes grown in central Israel. Preliminary tests indicate the new species has biocontrol activity against Botrytis rot of stored grapes. Phylogenetic analysis of domain D1/D2 26S rDNA sequences showed M. fructicola to be a sister species of M. pulcherrima.
Systematic and Applied Microbiology 12/2001; 24(3):395-9. · 3.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: ABSTRACT Eight strains of Metschnikowia pulcherrima isolated over a 4-year period from an unmanaged orchard and selected for their biocontrol activity against blue mold (caused by Penicillium expansum) of apples were characterized phenotypically, genetically, and for their biocontrol potential against blue mold on apples. All strains grew well and only differed slightly in their growth in nutrient yeast dextrose broth medium at 1 degrees C after 216 h, but large differences occurred at 0 degrees C, with strain T5-A2 outgrowing other strains by more than 25% transmittance after 360 h. This strain was also one of the most resistant to diphenylamine (DPA), a postharvest antioxidant treatment. All strains required biotin for growth in minimum salt (MS) medium, although strain ST2-A10 grew slightly in MS medium containing riboflavin or folic acid, as did ST3-E1 in MS medium without vitamins. None of the strains produced killer toxins against an indicator strain of Saccharomyces cerevisiae. Analysis of Biolog data from YT plates for all eight strains using the MLCLUST program resulted in separation of the strains into one major cluster containing four strains and four scattered strains from which strain ST1-D10 was the most distant from all other strains. This was particularly apparent in 3-D and principle component analysis. Genetic differentiation of the eight strains using maximum parsimony analysis of nucleotide sequences from domain D1/D2 of nuclear large subunit (26S) ribosomal DNA resulted in detection of two clades. Strain ST1-D10 grouped with the type strain of M. pulcherrima but the remaining seven strains grouped separately, which might possibly represent a new species. All strains significantly reduced blue mold on mature Golden Delicious apples during 1 month of storage at 1 degrees C followed by 7 days at room temperature, but strains T5-A2 and T4-A2 were distinctly more effective under these conditions. Strain T5-A2 also was the most effective in tests on harvest mature apples treated with the lowest concentration of the antagonist and stored for 3 months at 0.5 degrees C. Populations of all eight strains increased in apple wounds by approximately 2 log units after 1 month at 1 degrees C followed by 5 days at 24 degrees C. Our results indicate that M. pulcherrima is an excellent candidate for biological control of postharvest diseases of pome fruit. The variation in phenotypic, genetic, and biocontrol characteristics among strains of M. pulcherrima isolated from the same orchard should make it possible to select antagonists with characteristics that are most desirable for postharvest application.
[Show abstract][Hide abstract] ABSTRACT: Descriptions are given for the two new anamorphic ascomycetous yeasts Candida germanica (type strain NRRL Y-27064, CBS 4105) and Candida neerlandica (type strain NRRL Y-27057, CBS 434). The species were isolated, respectively, from the atmosphere over Germany and from pressed yeast cake in The Netherlands. Phylogenetic analysis of 26S domain D1/D2 ribosomal DNA sequences places C. germanica near Pichia philogaea, whereas C. neerlandica is a member of the Lodderomyces elongisporus/Candida albicans clade.
Antonie van Leeuwenhoek 11/2001; 80(1):77-83. · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Four new species of Candida are described based on their unique nucleotide sequences in the D1/D2 domain of large subunit (26S) ribosomal DNA. Candida peoriaensis (type strain NRRL YB-1497, CBS 8800) and C. ponderosae (type strain NRRL YB-2307, CBS 8801) are members of the Pichia anomala clade and were isolated in the U.S. from, respectively, the stump of an elm tree (Ulmus sp.) and from insect frass of a Ponderosa pine (Pinusponderosa). Candida ghanaensis (type strain NRRL YB-1486, CBS 8798) is a phylogenetically divergent species from soil in Ghana and appears related to the Dipodascus/Geotrichum clade. Candida litsaeae (type strain NRRL YB-3246, CBS 8799) was isolated from the frass of an insect-infested Litsaea polyantha tree from India, and is a divergent species that is most closely related to Candida ontarioensis.
Antonie van Leeuwenhoek 10/2001; 79(3-4):353-61. · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A new ascosporogenous yeast, Zygosaccharomyces kombuchaensis sp. n. (type strain NRRL YB-4811, CBS 8849), is described; it was isolated from Kombucha tea, a popular fermented tea-based beverage. The four known strains of the new species have identical nucleotide sequences in domain D1/D2 of 26S rDNA. Phylogenetic analysis of D1/D2 and 18S rDNA sequences places Z. kombuchaensis near Zygosaccharomyces lentus. The two species are indistinguishable on standard physiological tests used for yeast identification, but can be recognized from differences in restriction fragment length polymorphism patterns obtained by digestion of 18S-ITS1 amplicons with the restriction enzymes DdeI and MboI.
FEMS Yeast Research 08/2001; 1(2):133-8. · 2.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A description is given for Pichia hawaiiensis sp. nov., a nitrate-utilizing member of the genus Pichia E. C. Hansen emend. Kurtzman. Seven strains of the new species were isolated during the years 1972, 1973 and 1978 from rotting bark of the Hawaiian tree genera Charpentiera, Pisonia and Cheirodendron. P. hawaiiensis is heterothallic but appears to occur in nature mainly in the diploid state. Asci are deliquescent and produce up to four hat-shaped spores per ascus. Phylogenetic analysis of the 600 nucleotide D1/D2 domain of the 26S rDNA showed that P. hawaiiensis is most closely related to Pichia populi and Williopsis californica (syn. Hansenula californica). The type strain of P. hawaiiensis, isolated on the island of Hawaii from the rotting bark of Charpentiera sp. containing insect larvae, is strain UCD-FST 72-181T (= ATCC MYA-137T = CBS 8760T = NRRL Y-27270T).
International journal of systematic and evolutionary microbiology 08/2000; 50 Pt 4:1683-6. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An unknown yeast species was isolated from maize silage and was determined to be novel on the basis of morphological and physiological characteristics, nucleotide sequence of domain D1/D2 of LSU rDNA and from its electrophoretic karyotype. The name for the proposed new species is Saccharomyces bulderi Middelhoven, Kurtzman et Vaughan-Martini (type strain CBS 8638, NRRL Y-27203, DBVPG 7127). S. bulderi is closely related to S. barnettii and S. exiguus from which it can be distinguished by having a double vitamin requirement of biotin and thiamine and by no or slow aerobic growth on raffinose, a sugar that on the contrary is fermented rapidly. Gluconolactone is rapidly fermented with ethanol, glycerol and carbon dioxide being the main products.
Antonie van Leeuwenhoek 05/2000; 77(3):223-8. · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
Canadian Journal of Microbiology 02/2000; 46(1):50-8. · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Four new yeasts are described that were recognized as novel from nucleotide substitutions in domain D1/D2 of 26S rDNA, a region that is sufficiently divergent to allow resolution of most ascomycetous yeast species. The new species and their type strains are as follows: Pichia maclurae NRRL Y-5377T (= CBS 8671T); Pichia misumaiensis NRRL Y-17389T (= CBS 8062T); Candida mycetangii NRRL Y-6843T (= CBS 8675T); and Candida ulmi NRRL YB-2694T (= CBS 8670T). The two Pichia species form spherical ascospores and are heterothallic. Phylogenetic analysis of domain D1/D2 sequences placed the four new species in the Pichia anomala clade.
International journal of systematic and evolutionary microbiology 02/2000; 50 Pt 1:395-404. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An undescribed anamorphic yeast species of ascomycetous affinity, for which the name Candida tartarivorans is proposed, was isolated from dried wine lees in Portugal using a selective medium with L(+)-tartaric acid as the sole source of carbon and energy. The single isolate (IGC 4854T) showed the following characteristics: sympodial holoblastic conidiogenesis, absence of asci with ascospores, a negative colour reaction with Diazonium Blue B, production of elaborate pseudomycelium and ability to grow with inositol as sole source of carbon. Analysis of the physiological data pointed to a close relationship with other inositol-assimilating taxa, namely the genera Arxula, Stephanoascus, Sympodiomyces, Zygoascus and selected Candida species. Comparative analysis of the D1/D2 variable domain of the 26S rRNA gene of all available sequences for ascomycetous yeasts showed that strain IGC 4854T did not match with any other species in the database. The closest relative was Candida auringiensis Santa Maria, but the two species differed in 24 nucleotide positions. A description of the new species is given.
International journal of systematic and evolutionary microbiology 02/2000; 50 Pt 1:389-94. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A description is given of Pichia lachancei sp. nov., a new species of yeast that occurs in association with several Hawaiian plant species of the genera Tetraplasandra, Cheirodendron and Clermontia. The new species is heterothallic and occurs in nature in the haploid as well as the diploid state. Upon conjugation of complementary mating types, zygotes are formed that reproduce by budding as diploid cells. When placed on sporulation medium, four hat-shaped spores are produced which are rapidly released from the ascus. Phylogenetic analysis showed that P. lachancei is most closely related to Pichia rhodanensis and Pichia jadinii. The diploid type strain of P. lachancei, isolated from rotting bark of Tetraplasandra hawaiiensis on the island of Hawaii, is strain UCD-FST 79-9T (= ATCC 201914T = CBS 8557T = NRRL Y-27008T).
International journal of systematic bacteriology 08/1999; 49 Pt 3:1295-9. · 2.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Candida arabinofermentans (type strain NRRL YB-2248, CBS 8468), a new yeast that ferments the pentose L-arabinose, is described. The three known strains of this new species were isolated from insect frass of pine and larch trees in the U.S. Phylogenetic analysis of nucleotide sequences from the D1/D2 domain of large subunit (26S) ribosomal DNA places C. arabinofermentans among the methanol-assimilating yeasts and most closely related to Candida ovalis. Strains of the new species produce 0.7-1.9 g/l ethanol from L-arabinose.
Antonie van Leeuwenhoek 12/1998; 74(4):237-43. · 2.07 Impact Factor