Systematics of the genusCandida Berkhout: Proton magnetic resonance spectra of the mannose-containing polysaccharides of some further species ofCandida as an aid in classification

The proton magnetic resonance spectra of the mannose-containing polysaccharides of 48Candida species were determined. Two other species formed heteropolymers for which p.m.r. spectra could not be obtained. The species were grouped as follows: 17 species formed mannose-containing polysaccharides with spectra like those ofHansenula anomala, Pichia farinosa, Pichia membranaefaciens orPichia robertsii mannans; 12, like those ofMetschnikowia andDebaryomyces mannans; 6, like those of mannans ofSaccharomyces species; 4, like that ofTorulopsis bombicola mannan; and 4, like those ofCandida obtusa andCandida tepae polysaccharides. Five formed mannans whose spectra were unlike those of the mannans of any other yeast species examined.     

Systematics of the generaSaccharomyces,Schizosaccharomyces, Endomycopsis,Kluyveromyces, Schwanniomyces andBrettanomyces: Proton magnetic resonance spectra of the mannans and mannose-containing polysaccharides as an aid in classification

The proton magnetic resonance spectra of the mannans and mannose-containing polysaccharides of 71 species ofSaccharomyces,Schizosaccharomyces, Endomycopsis, Kluyveromyces, Brettanomyces,Nematospora andSchwanniomyces and of some apparently related species ofTorulopsis were determined, grouped according to similarities in the spectra, and compared with those of the mannose-containing polysaccharides of some other yeasts. The spectra of the mannans produced bySaccharomyces, Kluyveromyces, Nematospora, Brettanomyces andTorulopsis were placed in 10 groups. The galactomannans formed by theSchizosaccharomyces species studied had very similar spectra which were placed in a single group. The spectra of the mannans of theSchwanniomyces species were likewise placed in a single group. The spectra of the mannans of theEndomycopsis species studied were not alike and were placed in three sub-groups.Issued as N.R.C. No. 10812.The authors wish to express their gratitude to all those who supplied the cultures used in this work. In addition, they wish to thank Mr. M. Mazurek for the determination of the p.m.r. spectra, and Mr. N. R. Gardner and Mr. R. J. Magus for valuable technical assistance.     

Torulopsis bombicola sp. n.

A new yeast species,Torulopsis bombicola, is described, that produces extracellular hydroxy fatty acid sophorosides. It utilizes relatively few carbon compounds. It forms a mannan having a proton magnetic resonance spectrum similar to the spectra of the galactomannans ofTorulopsis apis, Torulopsis nodaensis andT. magnoliae, but differing from those ofT. gropengiesseri galactomannan andT. apicola mannan.Issued as N.R.C.C. No. 11234.The authors wish to thank Mr. M. Mazurek for the determination of the p.m.r. spectra, and Mr. N. R. Gardner and Mr. R. J. Magus for valuable technical assistance.     

Systematics of the genusCandida Berkhout: Proton magnetic resonance spectra of the mannans and mannose-containing polysaccharides as an aid in classification

The proton magnetic resonance (p.m.r.) spectra of the mannans, galactomannans and mannose-containing heteropolysaccharides of a number of species ofCandida were determined, and compared with the spectra of similar polysaccharides of some species of the sporogenous generaPichia, Hansenula, Endomycopsis, Debaryomyces andSaccharomyces. Similarities among the spectra were used as an aid in classification. TheCandida species studied were placed in four groups: 1) thoseCandida species classified as asporogenous forms of perfect species, 2) those which produce mannose-containing polysaccharides having p.m.r. spectra resembling those of the mannans of known perfect species, 3) members of theCandida parapsilosis group, 4) thoseCandida species which did not ferment glucose and which were not included in one of the other groups.Issued as N.R.C. No. 10566.The authors are grateful to all those who made the work possible by supplying the cultures and materials studied. They wish also to thank Mr. M. Mazurek for the determination of the p.m.r. spectra, and Mr. N. R. Gardner and Mr. R. J. Magus for valuable technical assistance.     

Immunochemical studies on mannans of the genusSaccharomyces

Antigenic mannans isolated from the cells ofSaccharomyces fermentati, Saccharomyces rosei,Saccharomyces delbrueckii, Torulopsis colliculosa, Candida albicans andSaccharomyces cerevisiae were examined for their reactivity withSaccharomyces fermentati andCandida albicans antisera. Mannans ofTorulaspora as well asCandida albicans showed high cross-reactivity with the investigated antisera, which could be due to the presence of long side chains established by the partial acetolysis method. The low specific rotations ofSaccharomyces fermentati, Saccharomyces rosei andTorulopsis colliculosa mannans indicate a predominance of β-glycosidio linkages, whereasSaccharomyces delbrueckii andCandida albicans mannans possess predominantly α-linkages.Saccharomyces cerevisiae mannan showed different structural and immunological properties.     

A proposal for amendment of the diagnosis of the genusPichia hansen

Summary An amended diagnosis has been given for the genusPichia Hansen to allow inclusion of species characterized by a lack of pellicle formation, by the absence or a strongly reduced pseudomycelium or by a combination of both properties. The following species fit the amended diagnosis ofPichia: P haplophila Shifrine et Phaff,P. carsonii Phaff et Knapp,P. quercibus Phaff et Knapp andP. xylosa Phaff, Miller et Shifrine. Furthermore, it has been proposed to transferSaccharomyces pastori Guilliermond,Saccharomyces pini Holst andDebaryomyces vini Zimmermann to the amended genusPichia, where they fit well rather than occupying and exceptional position in their present genera.     

Serological Relationships among Some Pichia Species

Antigenic analyses of five species of the genus Pichia were carried out for taxonomic study by the slide agglutination method using monospecific and absorbed antisera and the agglutinin absorption technique. Comparative studies were also performed with a few strains of each of the same species and their classifications are discussed with respect to the antigenic structures and the patterns of proton magnetic resonance (PMR) spectra of their cell wall polysaccharides. Pichia delftensis and Pichia zaruensis possessed thermostable antigens 1, 2, 5 and 11, and the former had also thermolabile antigen m. Both species were closely related to Candida krusei. Pichia toletana possessed thermostable antigens 1, 2, 5, 11, 17 and 49. Pichia bovis contained thermostable antigens 1, 2, 14, 15, 16, 20 and 21, and it was related to most species of the genus Hansenula, although assimilation of potassium nitrate was negative. Finally, Pichia etchellsii possessed thermostable antigens 1, 2, 3, 4, 9 and 14, and was closely related to Pichia vini. Patterns of PMR spectra of mannans of these species also supported their serological relationships. Therefore, P. delftensis, P. zaruensis and P. etchellsii are considered to be the synonyms of Pichia fluxuum, Pichia dispora and P. vini respectively, although P. toletana and P. bovis are independent species.     

Yeasts associated with pods and exudates of algarrobo trees (Prosopis spp.) and species of columnar cacti in northwest Argentina

Yeasts were isolated from exudates of algarrobo trees from nine sites in northwest Argentina, three in the Chaco region, from pods of algarrobo and acacia, collected in the Quebrada de Cafayate, and from rot pockets in decaying columnar cacti at Cachi (Parc Nacional des Cardons), and at Las Ruinas de Quilmes. Most of the yeasts isolated from exudates of algarrobo were identified asBullera variabilis, Candida famata, Cryptococcus albidus and otherCryptococcus species,Debaryomyces hansenii, Pichia angusta (Hansenula polymorpha),Pichia ciferrii, Pichia farinosa andTorulaspora delbrueckii. OtherCandida, Kluyveromyces andPichia species were found. Most species were osmotolerant. The high sugar content of the exudates influenced the nature of the yeast species present. The pods containedCryptococcus spp.,Candida famata andCandida ciferrii spp. Half the species isolated from rotting cactus wereCryptococcus species.Pichia membranaefaciens andTorulaspora delbrueckii were also isolated. Of 553 cultures investigated, 49 utilized methanol.Deceased on July 24th, 1995     

Relevance of the ecology ofCitrus yeasts to the diet ofDrosophila

A study of the yeast flora of necrotic oranges and associatedDrosophila yielded a total of 221 isolates composed ofKloeckera apiculata (75),Pichia fermentans (75),Pichia kluyveri (50),Torulopsis stellata (17),Hanseniaspora uvarum (2),P. membranaefaciens (1), andCandida vini (1). The yeast species of all samples of oranges and adultDrosophila were very similar; however, the speciesof Drosophila contained a higher proportion ofP. fermentans and a lower proportion ofK. apiculata than was found in the rotting oranges.P. fermentans was subsequently found more frequently on the surface of the necrotic tissue, where the flies feed, than was found internally. SinceP. fermentans characteristically produces a pellicle and pseudomycelium andK. apiculata does not, it is concluded that the growth characteristics of the yeasts are an important factor determining adultDrosophila diets.     

Biochemical and Immunochemical Studies of Fungi

Crude mannans extracted from Candida albicans and Saccharomyces cerevisiae by autoclaving yeast cells in citrate buffer (pH 7.0) according to Peat's method, were fractionated repeatedly by column chromatography on DEAE-Sephadex, acetate form, yielding neutral and acidic mannans. The former fraction showed a single peak by boundary electrophoresis and ultracentrifugal analysis, while the latter contained small amounts of phosphorus and protein. Using purified mannans as controls, various serological experiments were carried out with mannan antigens extracted from C. albicans with 45% phenol water and with 3% NaOH. No remarkable differences were observed in the antigenic activity of 4 mannan antigens from C. albicans, and the purified mannan exhibited very high antigenic activity. It was found that the mannan of S. cerevisiae was antigenically less specific than that of C. albicans mannan. The difference in serological specificity between mannans of both species may reflect not only differences in mannopyranose linkages but differences in the structure of the macromolecules.     

Mannose-containing Polysaccharides of the Apiculate Yeasts Nadsonia, Hanseniaspora, Kloeckera, and Saccharomycodes, and Their Use as an Aid in Classification

The mannose-containing polysaccharides formed by species of Nadsonia, Hanseniaspora, Kloeckera, and Saccharomycodes were extracted with hot aqueous alkali and purified by precipitation as their copper complexes. N. fulvescens and N. elongata formed galactomannans, while Hanseniaspora and Kloeckera species and S. ludwigii formed mannans. H. valbyensis, H. uvarum, and K. apiculata were a group which formed mannans which had identical H-1 regions in their proton magnetic resonance (PMR) spectra, and H. osmophila, K. africana, and K. magna mannas formed another group based on similar spectra. K. javanica formed a mannan with an H-1 spectral region which resembled that of the H. valbyensis group in some respects and that of the H. osmophila group in others. The H-1 portion of the PMR spectrum of S. lugwigii mannan was very complex and was unlike that of any other apiculate yeast studied.     

Systematics of the genusTorulopsis: proton magnetic resonance spectra of the mannose-containing polysaccharides as an aid in classification

The proton magnetic resonance spectra of the mannose-containing polysaccharides of 42Torulopsis species were determined and used as a basis for placing these species in seven groups. Five of the groups consisted of species which formed mannose-containing polysaccharides with spectra whose H-1 regions were like those of the mannans and galactomannans of species ofSaccharomyces, Pichia, Hansenula, Debaryomyces orMetschnikowia. The sixth group consisted ofTorulopsis bombicola, Torulopsis apicola and a number of other yeasts which were mostly sugar- and salt-tolerant. The seventh group consisted of species whose mannose-containing polysaccharides had spectra unlike those in the preceding groups. Some of the spectra had similarities to those of the mannose-containing polysaccharides of a miscellany of yeast species.     

Glucomannan fromCandida utilis

Structure of the glucomannan isolated from the cell walls ofCandida utilis has been investigated using acetolysis fragmentation, methylation analysis, and NMR spectroscopy. The structure of the glucomannan resembles that of the cellular mannans of otherCandida species, except that the longer tetra- and pentasaccharide side-chains are terminated with a glucosyl residue. Presence of the nonreducing glucosyl groups at the ends of the side-chains caused theC. utilis not to cross-react in a double immunodiffusion test with otherCandida species that possess mannan antigens and cross-react withHansenula species with glucomannan antigens.     

The taxonomy of yeasts found in exudates of certain trees and other natural breeding sites of some species ofDrosophila

Summary A survey was made of the yeasts occurring in slime fluxes ofQuercus kellogii (black oak),Abies concolor (red fir) and in certain mushrooms and dead logs in the mountains of the Yosemite region of California. Most of the 134 isolates identified were found to be non-fermentative or poorly fermentative (fermenting glucose only and usually weakly). The isolates were placed in the following genera:Pichia (34),Debaryomyces (35), imperfect forms ofHansenula (39),Endomyces (3),Saccharomyces (2),Candida (11),Trichosporon (7),Torulopsis (1),Cryptococcus (1) andSporobolomyces (1). Four new species have been described,Pichia silvestris, Pichia quercibus, Pichia carsonii andDebaryomyces fluxorum. P. quercibus andP. carsonii are unusual representatives of the genusPichia in that they form a very primitive pseudomycelium and lack pellicles on malt extract. To accommodate such species an amended diagnosis of the genusPichia has been proposed byPhaff in an accompanying paper.Saccharomyces pastori, of which 12 isolates were obtained, has been transferred to the amended genusPichia asP. pastori (Guilliermond) nov. comb.     

Immunologic significance of diverse specificity of monoclonal antibodies against mannans of Candida albicans

Two agglutinating IgM mAb against mannan Ag of Candida albicans strains were investigated for their specificity. The agglutinating patterns of both mAb with a panel of stationary phase of yeast cells of standard strains did not match those of any known polyclonal antibody (PAb) factors. The reactive patterns of both mAb for a given panel of 202 isolates of seven Candida species and the mode of competitive binding between mAb and a PAb factor, as determined by a combination of direct and indirect immunofluorescence staining, demonstrated that the two mAb were a part of PAb factor 4 (a prescribed reactive pattern of adsorbed PAb) but were different from each other in their specificity. The thereby designated mAb 4b and 4c were tested under PAb factor 4-positive Candida strains and further division into two to three serotypes of each species were made. 1H-Nuclear magnetic resonance spectra (500 MHz) of purified neutral mannans from strains of each serotype showed that although the 1H-nuclear magnetic resonance spectra of mannans from two subtypes of C. albicans serotype A and from each of two serotypes of Candida guilliermondii and Candida glabrata were identical or similar, the two mAb were still able to distinguish their fine determinant structures. Our findings suggest that mAb with entirely identical specificity cannot be produced against even the same determinant groups of mannan. In addition, the fact that microheterogeneity may occur without limit in the mannans of the strains suggests that antibodies with unlimited diverse specificities are produced directed against these antigenic varieties as well.     

Yeast communities of the cactusPilosocereus arrabidae as resources for larval and adult stages ofDrosophila serido

The feeding behavior ofDrosophila serido on the yeast communities of necrotic stem tissue ofPilosocereus arrabidae were studied in a sand dune ecosystem of Rio de Janeiro, Brazil. The prevalence of cactophilic yeasts includingPichia barkeri, Candida sonorensis andGeotrichum sp. in the crops and external surfaces ofD. serido reflected its association with the cactus habitat. The effective number of yeasts vectored on the surface of flies was higher than that in the crops. Also overlap between the yeasts from stems and from crops was partial suggesting selective feeding by the flies in the substrates visited. The females had a higher effective number of yeast species and a lower similarity than males with the yeast community ofP. arrabidae. This was probably related to the search for oviposition sites by females. The presence ofPichia thermotolerans-like andPichia amethionina varpachycereana in the flies, but not inP. arrabidae stems, indicated thatD. serido was not limited to this cactus species. The larvae and adults lived in different patches with the adults feeding in patches with higher yeast species richness. The larvae had a narrower feeding niche and higher overlap withP. arrabidae, and preferredP. barkeri andPichia cactophila as food. Adult flies fed on patches with the most frequent yeasts except forP. cactophila. Pichia caribaea was found in higher frequency in the adult crops than in the stems. Our data suggested that there was food selection and diet partitioning between adult and larval stages ofD. serido.     

Relative Incidence of Ascomycetous Yeasts in Arctic Coastal Environments

Previous studies of fungi in polar environments have revealed a prevalence of basidiomycetous yeasts in soil and in subglacial environments of polythermal glaciers. Ascomycetous yeasts have rarely been reported from extremely cold natural environments, even though they are known contaminants of frozen foods. Using media with low water activity, we have isolated various yeast species from the subglacial ice of four glaciers from the coastal Arctic environment of Kongsfjorden, Spitzbergen, including Debaryomyces hansenii and Pichia guillermondii, with counts reaching 10⁴ CFU L⁻¹. Together with the basidiomycetes Cryptococcus liquefaciens and Rhodotorula mucilaginosa, these yeasts represent the stable core of the subglacial yeast communities. Other glacial ascomycetous species isolated included Candida parapsilosis and a putative new species that resembles Candida pseudorugosa. The archiascomycete Protomyces inouyei has seldom been detected anywhere in the world but was here recovered from ice in a glacier cave. The glacier meltwater contained only D. hansenii, whereas the seawater contained D. hansenii, Debaryomyces maramus, Pichia guilliermondii, what appears to represent a novel species resembling Candida galli and Metschnikowia bicuspidata. Only P. guilliermondii was isolated from sea ice, while snow/ice in the fjord tidal zone included C. parapsilosis, D. hansenii, P. guilliermondii and Metschnikowia zobellii. All of these isolated strains were characterized as psychrotolerant and xero/halotolerant, with the exception of P. inouyei.     

Yeast Diversity in Hydromorphic Soils with Reference to a Grass–Sphagnum Wetland in Western Siberia and a Hummocky Tundra Region at Cape Barrow (Alaska)

The microbiological analysis of 78 samples taken from a high bog in Western Siberia and from a tundra wetland soil in Alaska showed the presence of 23 yeast species belonging to the genera Bullera, Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Metschnikowia, Mrakia, Pichia, Rhodotorula, Saccharomyces, Sporobolomyces, Torulaspora, and Trichosporon.Peat samples from the high bog were dominated by eurytopic anamorphic basidiomycetous species, such as Rhodotorula mucilaginosaand Sporobolomyces roseus, and by the ascomycetous yeasts Candidaspp. and Debaryomyces hansenii.These samples also contained two rare ascomycetous species (Candida paludigenaand Schizoblastosporion starkeyi-henricii), which so far have been found only in taiga wetland soils. The wetland Alaskan soil was dominated by one yeast species (Cryptococcus gilvescens), which is a typical inhabitant of tundra soils. Therefore, geographic factors may serve for a more reliable prediction of yeast diversity in soils than the physicochemical or ecotopic parameters of these soils.     

Clavispora opuntiae and other yeasts associated with the mothSigelgaita sp. in the cactusPilosocereus arrabidae of Rio de Janeiro,Brazil

Summary Clavispora opuntiae was the prevalent yeast associated with the feeding sites ofSigelgaita sp. larvae in the cactusPilosocereus arrabidae. Also associated with this habitat wereCandida sonorensis, Pichia cactophila, Pichia barkeri, Candida sp. A,Geotrichum sp.,Geotrichum sericeum and the yeast like organismsPrototheca zopfii andAcremonium sp. Atypical yeast biotypes that may represent new species ofPichia, Sporopachydermia andCandida were isolated. Mating types ofClavispora opuntiae were at a ratio 70 h⁺ to 3 h^- and reduced levels of sporulation suggested low pressure for sexual reproduction in this habitat.Sigelgaita sp. probably was not an important vector forClavispora opuntiae because it was not isolated from an adult or eggs of this moth.     

Two new species ofPichia isolated from slime fluxes of deciduous trees

Two new homothallic species ofPichia, associated with exudates ofPopulus trichocarpa andSalix sp. have been described.Pichia trehalophila sp.n. was isolated from slime exudates in two widely separatedPopulus trichocarpa trees andPichia salictaria sp.n. was isolated from two exudates ofSalix sp. The latter species was previously present as an unidentified strain ofPichia in the culture collection of the Centraalbureau voor Schimmelcultures and had been isolated from a patient in Germany. The natural habitat ofP. salictaria is considered to be in association with willow trees.