Apparent bisexual behavior of yeast strains obtained from hybridization of industrial yeasts of the genus Saccharomyces with auxotrophic diploids

During a genetic study of some hybrids of brewer's and distiller's yeast strains with impaired sporulation characteristics and genetically marked auxotrophic aa and alpha alpha diploids, strains which showed positive mating reactions with both a and alpha haploid tester strains were observed. These strains proved to be homothallic and sporulated freely. The original hybrids, which appeared to be tetraploid, usually yielded sporulating single-spore clones on dissection of asci formed from them, with few or no mating strains among them. Dissection of asci from these clones yielded some single-spore clones which showed mating reactions with one or the other or both haploid tester strains, and further selection produced strains which on sporulation and dissection yielded single-spore clones which were apparently bisexual and sporulated freely. These strains proved to be homothallic, yielding single-spore clones which were all of the a mating type, and in which the mating reaction and, possibly, the action of the genes for homothallism were impaired, so that sporulating, non-mating diploids and haploids of both mating types were present in cultures originally obtained as single-spore clones.

Removal of resin acids from culture media and kraft-mill effluents by yeasts and some other fungi

Epicoccum nigrum, Rhinocladiella mansonii, Rhodotorula minuta, and Trichosporon cutaneum were tested for their ability to remove resin acids from supplemented kraft-mill effluent and from a medium containing yeast extract as sole nitrogen source. Up to 39% of the resin acid content was removed by all four organisms. The mutagenic activity of the resin acid preparation, as measured by the induction of gene conversion in a strain of Saccharomyces cerevisiae, was low or non-existent.

Yeasts occurring in the effluent disposal basins of a pulp mill in Saskatchewan

The numbers of yeasts in the effluent disposal system of the Prince Albert, Saskatchewan Pulp Mill occasionally reached 1 × 106 cells/liter, but were usually below 5 × 105 cells/liter. Rhodotorula species were commonly isolated and sometimes amounted to half of the population, though usually the relative numbers were considerably lower. The highest counts were found in late summer and early autumn. Bacterial counts varied from 20 × 106 to 74 × 106 cells/ml. Chemical O2 demand (COD) reached about 1200 mg/liter at times, and decreased as the effluent moved through the disposal system, about 40% of the total COD being removed during the treatment process. A considerably wider range of yeast species was found in the pulp mill disposal basins than in the Saskatoon sewage treatment plant. Most of the ascosporogenous yeasts found were Hansenula or Pichia species usually occurring in association with trees, as were many of the Candida species isolated.

Yeasts isolated from some lakes and rivers of Saskatchewan

Yeasts were isolated from lakes in northern Saskatchewan, from the Saskatchewan River between Prince Albert and Cumberland House, and from three small lakes near Saskatoon, two of which form part of recreational areas. Yeast and bacterial counts were relatively low, less than 400 yeast cells/liter, except in samples taken near towns and industrial plants which discharged waste into the rivers or lakes. There was little change in the numbers of yeast cells in waters used for recreational purposes only, but the number of species isolated increased considerably. Most of the yeasts isolated from the other lakes and rivers were species known to occur in association with trees and in soils.

13 C magnetic resonance and structural studies on the mannose-containing polysaccharides of some Pichia and Hansenula spp

Mannose-containing polysaccharides were isolated from the cell walls of six Pichia and Hansenula species. These species were chosen from a group of 24 yeasts having polysaccharides with a similar spectrum, each giving proton magnetic resonance spectra with signals at τ4.24 and τ4.36. The polysaccharides were equated or distinguished by their 13C magnetic resonance (c.m.r.) spectra into three groups based on differing structures. The validity of this technique was borne out by conventional structural determinations. The polysaccharides were found to represent a new structural type, being predominantly linear and containing predominant (1 → 6)-linked α-D-mannopyranose units with (1 → 2)-linked units distributed regularly along the main chains.Some of the signals of the Hansenula capsulata mannan could be assigned to certain carbons indicating that the c.m.r. technique may have uses in structural investigations.

The genetic control of the two types of mannan produced by Saccharomyces cerevisiae

The two mannans formed by different strains of Saccharomyces cerevisiae give proton magnetic resonance spectra (spectral types A and B), which suggests that they differ principally in the presence of a-(1 → 3)-linked mannopyranosyl end units of the side chains of the more complex type (giving spectral type B). The presence or absence of such end units was under the control of a single mendelian gene, since the two types of mannan segregated independently during sporulation. The gene controlling this type of mannan produced was apparently not linked to those controlling the requirements for adenine, uracil, leucine, or histidine. The implications of the findings concerning the mechanism of biosynthesis of yeast mannan are discussed.

Yeasts of the matador soils of Saskatchewan and their ability to use flavonoids

The numbers of yeasts of the soils of the Matador site of the International Biological Program, in southern Saskatchewan, varied from about 1400 to 10 000 cells/g soil in the surface layer and from 600 to 1800 cells/g in the subsurface layers. Most of the cultures isolated were Cryptococcus albidus and its variety diffluens, Cryptococcus laurentii, and Cryptococcus terreus. A few cultures of Cryptococcus dimennae, Rhodotorula minuta, Sporobolomyces pararoseus, and Sporobolomyces salmonicolor were also isolated. Most of the cultures isolated could use rutin and many of them used the other flavonoids tested. Many of them used phloroglucinol and a few used naphthalene.

Yeasts isolated from soils of citrus orchards and citrus waste disposal areas in California and Florida: flavonoid utilization

Yeasts were isolated from soils from citrus orchards and citrus waste disposal areas in California and Florida. Species of Trichosporon, Cryptococcus, and Rhoclotorula were predominant. Strains of Hansenula saturnus, Hansenula californica, Hansenula mrakii, Pichia kluyveri, Saccharomyces rosei, Saccharomyces cerevisiae, and some species of Candida and Torulopsis were also found. The cultures isolated were tested for the ability to use a number of flavonoids. These compounds were used by strains of Trichosporon cutaneum, Cryptococcus albidus and its variety diffluens, Cryptococcus terreus, Cryptococcus lanrentii, Rhodotorula glutinis, Rhodotorula minuta, Rhodotorula rubra, and Candida humicola, but not by the ascosporogenous species or the other Candida species. Contrary to expectations, most of the cultures which used flavonoids were isolated from the orchard soils rather than from the soils of the waste disposal areas.

Yeasts isolated from the South Saskatchewan, a polluted river

Minimum numbers of yeasts isolated from the Saskatchewan River in the summers of 1964 and 1965 ranged from 400 to 500 cells/liter upstream from the city of Saskatoon, to 4600 cells/liter immediately downstream. In the summer of 1968, a period of extremely low water, the counts were 150 cells/liter upstream from the city and 30 000 cells/liter downstream.Proton magnetic resonance spectra of the mannose-containing polysaccharides from representative cultures of the different species isolated were used as an aid in classification. Most of the species were asporogenous, and included representatives of the genera Candida, Trichosporon, Rhodotorula, Torulopsis, and Cryptococcus. Some species of Pichia, Saccharomyces, and Debaryomyces were isolated. The yeasts were mostly introduced into the river with the effluent from the Saskatoon sewage system.

Proton magnetic resonance spectra of the mannans of some new species of Hansenula and their phylogenetic significance

The proton magnetic resonance spectra of the mannose-containing polysaccharides from some new species of Hansenula were obtained and used as an aid in establishing their phylogenetic relationships to other members of the genus. The spectrum of the mannan from Hansenula dimennae is identical with that of the mannan from Hansenula californica. These two haploid species are taxonomically closely related and are adjacent on the same line of the phylogenetic diagram according to Wickerham. Hansenula saturnus var. subsufficiens mannan has a spectrum like those of the mannans of some strains of Hansenula mrakii and Hansenula beijerinckii. The new species Hansenula henricii, Hansenula nonfermentans, and Hansenula glucozyma all form mannans with spectra having characteristic signals at about τ4.24 and τ4.38, as do the spectra of the mannans formed by the other species on the same phylogenetic line, Hansenula polymorpha, Hansenula minuta, and Hansenula wickerhamii. These species have, relatively, DNA's with the highest guanine and cytosine percentages in the genus. Hansenula platypodis, a species which, unlike other Hansenula species, forms ascophores and anastomoses, has DNA with a lower content of guanine plus cytosine. The spectrum of H. platypodis mannan is like that of H. minuta mannan, with the exception of two small signals at τ4.44 and τ4.48 which do not occur in the spectrum of H. minuta mannan.

Yeasts isolated from bumblebee honey from western Canada: identification with the aid of proton magnetic resonance spectra of their mannose-containing polysaccharides

Yeasts were isolated from bumblebee honey collected in the Pincher Creek region of southwestern Alberta and the Melfort and Saskatoon regions of central Saskatchewan. The predominant species isolated were Torulopsis bombicola n. sp., which produces hydroxy fatty acid sophorosides, a Candida species which resembles it in its assimilatory reactions but which does not produce sophorosides, and Saccharomyces rouxii. A few cultures of Debaryomyces phaffii and Candida reukaufii were isolated. The mannans or galactomannans formed by representatives of each group were extracted and their proton magnetic resonance spectra determined and used as an aid in identification of the different species.

Changes produced in hop extract components by yeasts

A number of yeasts, many of which were originally isolated from spoiled beer and similar sources, were tested for their ability to degrade or modify some of the components of hop extract. The yeasts could be divided into three major groups: those which caused little change in the composition of the steam-distillable components of the hop extract – yeast extract medium; those which apparently modified one or more components as determined by the shifting of a major peak on the gas–liquid chromatogram; and those which caused extensive degradation and complete disappearance of the major steam-distillable components of the hop extract medium.

Systematics of the genera Hansenula and Pichia: proton magnetic resonance spectra of their mannans as an aid in classification

The proton magnetic resonance (p.m.r.) spectra of the mannans extracted from a number of species of Hansenula and Pichia were determined, and the species in each genus grouped according to similarities in the p.m.r. spectra. Some of the groups of Pichia species formed mannans having similar spectra to those produced by some species of Hansenula. Several Candida species produced mannans having spectra similar to those of Pichia species. Pichia vanrijii formed a mannan whose spectrum resembled the spectra of the mannans formed by Schwanniomyces species. Pachysolen tannophilus formed a mannan with a spectrum resembling those of Hansenula holstii and Hansenula capsulata. Citeromyces matritensis and its asporogenous form Torulopsis globosa formed mannans unlike those of any other yeast studied.