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     

Pichia angophorae,sp.n. from the exudate of an Australian Red Gum tree

A new species ofPichia has been described.Pichia angophorae sp.n. was the only yeast present in an exudate ofAngophora costata collected near North Ryde, N. S. W., Australia. The new species exists in both the homo- and heterothallic state. Heterothallic mating types have been isolated as segregants from originally homothallic cultures.     

DNA relatedness among saturn-spored yeasts assigned to the generaWilliopsis andPichia

Saturn-spored species assigned to the generaWilliopsis andPichia were compared from extent of nuclear DNA complementarity. Of thePichia spp., four were recognized as distinct taxa:P. dispora, P. saitoi, P. zaruensis andPichia sp. nov. AmongWilliopsis spp., the following were accepted:W. californica, W. mucosa comb. nov.,W. pratensis, W. saturnus var.saturnus, W. saturnus var.mrakii comb. nov.,W. saturnus var.sargentensis comb. nov.,W. saturnus var.subsufficiens comb. nov. andWilliopsis sp. nov. The newPichia andWilliopsis species are described elsewhere. Moderate (36–68%) DNA relatedness was detected between the formerPichia sargentensis and varieties ofW. saturnus again demonstrating that nitrate assimilation is not a reliable criterion for separating yeast species.     

Pichia spartinae sp. n. from Louisiana marshland habitats

A new species ofPichia has been described.Pichia spartinae was one of the predominant yeasts isolated from the rhizosphere and tissue of oyster grass,Spartina alterniflora, in the Louisiana marshland. The species occurs in the environment in both the homo- and heterothallic state. This is the first species ofPichia in high densities in an estuarine locality.We wish to express our gratitude to Mr. J. C. Raadschelders for correcting the latin diagnosis.     

Yeast communities of the cactusPilosocereus arrabidae and associated insects in the Sandy Coastal Plains of Southeastern Brazil

The yeast communities from necrotic tissues, decaying flowers and fruits, and from larval feeding sites of the mothSigelgaita sp. in the cactusPilosocereus arrabidae were surveyed in three restinga ecosystems in Southeastern Brazil. Insects associated with these substrates were sampled to verify the vectoring of yeasts. The cactusPilosocereus arrabidae was shown to have four different yeast communities associated with it. Necrotic stems had a diverse yeast community with the prevalent speciesPichia barkeri, Candida sonorensis, Pichia cactophila, Geotrichum sp.,Myxozyma mucilagina andSporopachydermia sp. A, representing about 80% of the total isolates.Pichia sp. A and aCandida domercqii-like species represented more than 90% of the yeast isolates from decaying flowers. Fruits had a heterogeneous yeast community with typical fruit yeasts of the genusKloeckera, basidiomicetous anamorphs of the genusCryptococcus, the black yeastAureobasidium pullulans, Pichia sp. A, aCandida domercqii-like species, and some cactophilic yeasts, especiallyClavispora opuntiae. The feeding site ofSigelgaita sp. larvae hadClavispora opuntiae as the prevalent species. Insect vectors are suggested as one the most important factors influencing the composition of these yeast communities.     

Systematics of the generaDebaryomyces andMetschnikowia: Proton magnetic resonance spectra of their mannans as an aid in classification

The proton magnetic resonance spectra of the mannans of a number ofDebaryomyces andMetschnikowia species (Endomycetales) were determined. The spectra of all of the mannans had several similar characteristics, regardless of the species from which they originated. Pichia vini, a species originally classified asDebaryomyces vini, formed a mannan with a spectrum almost identical with those ofMetschnikowia (Candida) reukaufii andPichia haplophila. Debaryomyces vanrijii, originally placed in the genusPichia, formed a mannan with a spectrum identical with those ofPichia robertsii andCandida (Pichia) guilliermondii mannans.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.     

Pichia besseyi sp. n.

A new species ofPichia has been described.Pichia besseyi was isolated from a marsh near the town of Bonaventure, Gaspé Peninsula, Quebec, Canada. The hemispheroidal shape of the ascospores of this species is particularly noteworthy.     

Synonomy of the yeast generaHansenula andPichia demonstrated through comparisons of deoxyribonucleic acid relatedness

The relationship between the generaHansenula andPichia was examined through comparisons of DNA relatedness among phenotypically similar species.Hansenula minuta andPichia lindneri showed 75% DNA base sequence complementarity. In other comparisons,H. nonfermentans was found to share nearly 50% of its DNA sequences with bothH. minuta andP. lindneri. Because of the high degree of relatedness observed, it is proposed that ability to assimilate nitrate, the sole distinction betweenHansenula andPichia, is of insufficient taxonomic value for the reliable separation of either species or genera. Hat-spored species ofHansenula H. et P. Sydow 1919 are being transferred toPichia Hansen 1904. Species ofHansenula andPichia with Saturn-shaped ascospores will be transferred to the genusWilliopsis. The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Yeasts associated with algarrobo trees (Prosopis spp.) in northwest Argentina: A preliminary report

Summary Yeasts were isolated from exudates from trees at three sites in northwest Argentina, two between the towns of Amaicha del Valle and Cafayate and one in the Quebrada de Cafayate, a deep river valley north of Cafayate. The majority of the yeasts were identified asCandida famata andRhodotorula graminis, though isolates of other species ofRhodotorula, Candida boidinii, Pichia membranaefaciens, and occasional isolates of other species were obtained. None of the species was the same as those isolated in Crete, from pods of the carob (European algarrobo). Of 96 cultures investigated, 26 utilized methanol as sole carbon source. The frequency of isolation of methylotrophic yeasts from this habitat may prove to be of considerable scientific and technological interest.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.     

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.     

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.     

Pichia scaptomyzae sp. nov., isolated from Scaptomyza multispinosa Malloch (Diptera) in southern Chile

A novel representative of the yeast genus Pichia which has been isolated from the intestinal tract of the fly Scaptomyza multispinosa Malloch, (species of Chilian diptera frequenting meadows where Ranunculus repens L. are abundant), is described and illustrated. The strain differs from all accepted Pichia species (1–11) to warrant its establishment as a new species: Pichia scaptomyzae sp. nov.     

Ribosomal RNA genes structure in somePopulus spp. (Salicaceae) and their hybrids

The tandemly repeated multigene families encoding 18S and 25S rRNAs were studied at the restriction enzyme level inPopulus alba L.,Populus deltoides Bartr. exMarsh.,Populus trichocarpa Torr. & Gray and in the hybrids between the last two mentioned species. The analysis of single and double digestion with EcoRI, BamHI, XbaI, and SstI endonucleases showed the presence of single repetitive unit types of 12.25 and 11.75kb inP. alba andP. trichocarpa, respectively.P. deltoides showed two rDNA gene types having the same length (12.25Kb) but different nucleotide sequence in the IGS. The rDNAs genes ofP. deltoides andP. triochocarpa are inherited codominantly in their hybrids.     

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.     

Diazotrophic endophytes of native black cottonwood and willow

Poplar and willow are economically-important, fast-growing tree species with the ability to colonize nutrient-poor environments. To initiate a study on the possible contribution of endophytes to this ability, we isolated bacteria from within surface-sterilized stems of native poplar (Populus trichocarpa) and willow (Salix sitchensis) in a riparian system in western Washington state. Several of the isolates grew well in nitrogen-limited medium. The presence ofnifH, a gene encoding one of the subunits of nitrogenase, was confirmed in several of the isolates including species ofBurkholderia, Rahnella, Sphingomonas, andAcinetobacter. Nitrogenase activity (as measured by the acetylene reduction assay) was also confirmed in some of the isolates. The presence of these diazotrophic microorganisms may help explain the ability of these pioneering tree species to grow under nitrogen limitation.     

Pichia nongkratonensis sp. nov., a new species of ascomycetous yeast isolated from insect frass collected in Thailand

A yeast strain isolated from insect frass collected in Thailand was found to represent a new species of the genus Pichia. It is described as Pichia nongkratonensis sp. nov. In the phylogenetic tree based on the D1/D2 domain sequences of 26S rDNA, this yeast constitutes a cluster with Pichia dryadoides with high bootstrap confidence level; however, it differs from the latter species by 5.6% base substitutions. Pichia nongkaratonensis resembles P. dryadoides also in the phenotypic characteristics but is distinguished from this species by the assimilation of several carbon and nitrogen compounds.     

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.     

Differential toxinogenesis in the genusPichia detected by an anti-yeast killer toxin monoclonal antibody

The differential toxinogenesis of 25 isolates belonging to species of the potential yeast killer genusPichia that were previously classified in the genusHansenula was comparatively demonstrated by two serologic techniques (indirect immunofluorescence and double immunodiffusion) by using a monoclonal antibody against a yeast killer toxin produced by a selected strain ofPichia anomala (UCSC 25F). The killer phenotypes of thePichia isolates were evaluated by their ability to kill each other. The results, although of insufficient taxonomic value for a reliable separation of either species or genera, attest to the genomic heterogeneity for the killer character in the genusPichia as well as the presumptive dual killer/sensitive identity for each single isolate.     

New species and records of saprophytic ascomycetes (Myxotrichaceae) from decaying logs in the boreal forest

Decayed wood from fallen white spruce (Picea glauca) and trembling aspen (Populus tremuloides) collected in northeastern Alberta, Canada, was the source of new isolates of species in the ascomycete generaGymnostellatospora andPseudogymnoascus. In addition to new reports ofG. japonica, G. frigida andP. roseus, two new species are described.Gymnostellatospora canadensis sp. nov. resemblesG. japonica but differs in producing brown ascomata and in the formation of an arthroconidial anamorph.Gymnostellatospora subnuda sp. nov. is distinct in lacking differentiated peridial hyphae.Gymnostellatospora alpina was not found in decayed wood but is reviewed based on extralimital material. A dichtomous key to the five species ofGymnostellatospora is provided.