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.     

Formation of Extracellular C14-C18 2-D-Hydroxy Fatty Acids by Species of Saccharomycopsis

Eighteen of 19 strains of Saccharomycopsis fibuligera and one of two strains of S. capsularis produced mixtures of C(14)-C(18) 2-D-hydroxy acids in liquid culture medium. The mixture of these acids showed antimicrobial activity against Vibrio tyrogenus but not against the other microorganisms tested. Candida lactosa, a recently described species, was shown to be an isolates of S. fibuligera.     

Phylogenetic analysis of ascomycete yeasts that form coenzyme Q-9 and the proposal of the new genera Babjeviella, Meyerozyma, Millerozyma, Priceomyces, and Scheffersomyces

Species assigned to the genera Debaryomyces, Lodderomyces, Spathaspora, and Yamadazyma, as well as selected species of Pichia and Candida that also form coenzyme Q-9, were phylogenetically analyzed from the combined sequences of the D1/D2 domains of the large subunit and the nearly complete small subunit rRNA genes. Species assigned to Debaryomyces partitioned into three clades and species assigned to Pichia were distributed among six clades. These well-supported clades were interpreted as genera, and from this analysis, the following new genera are proposed: Babjeviella, Meyerozyma, Millerozyma, Priceomyces, and Scheffersomyces. The genus Schwanniomyces was reinstated and emended, and the genus Yamadazyma was phylogenetically defined. From this study, 23 new combinations and 3 new ranks are proposed. The preceding genera are members of a single, large clade, and it is proposed to delineate this clade as the new family Debaryomycetaceae.     

Emergence of regulatory CD4+ T cell response to repetitive stimulation with antigen-presenting cells in vitro: implications in designing antigen-presenting cell-based tumor vaccines

Because APCs play a crucial role in the generation of T cell-mediated immune responses, numerous clinical trials with APC-based vaccines have been initiated in different types of human cancers. Encouraging results have emerged from some of these initial studies. Thus far, APC-based vaccinations usually include multiple rounds of immunization. With this approach, although we and others have detected induction of Ag-specific CTL responses in vaccinated patients after stimulation with the same APC-based immunogen, in vitro we also find that repetitive in vitro stimulation with Ag-loaded APC can, at times, lead to the emergence of noncytolytic CD4+ T cells exhibiting the characteristic phenotype of Th2 cells. These noncytolytic CD4+ T cells synthesize large quantities of type 2 cytokines such as IL-4 and IL-10 on stimulation with the autologous APC or tumor cells in an MHC class II-restricted manner. Further, these CD4+ T cells and a cell-free supernatant factor block the activation of fresh T lymphocytes. The supernatant factor also exhibits a marked inhibitory effect on the expression of the costimulatory molecules, CD80 and CD86, by APC. The inhibitory effect of the supernatant factor can be abrogated by neutralizing IL-10 in the supernatant. These observations therefore have implications in the APC-based tumor vaccine protocol design.     

<Emphasis Type="Italic">Trichomonascus petasosporus</Emphasis> sp. nov. and <Emphasis Type="Italic">Sympodiomyces indianaensis</Emphasis> sp. nov., two new members of the Saccharomycetales

Two new yeasts are described that were recognized as novel from nucleotide divergence in domains D1/D2 of 26S rDNA. The new species and their type strains are the following: Trichomonascus petasosporus NRRL YB-2092T (CBS 9602T), mating type a, NRRL YB-2093 (CBS 9603), mating type alpha, and Sympodiomyces indianaensis NRRL YB-1950T (CBS 9600T). Phylogenetic analysis placed the two new taxa, which are sister species, in the Sympodiomyces clade near Blastobotrys/Stephanoascus farinosus. Placement of Trichomonascus in the Saccharomycetales resolves the earlier uncertainties surrounding the classification of this morphologically unusual genus.     

Phylogenetic circumscription of Saccharomyces, Kluyveromyces and other members of the Saccharomycetaceae, and the proposal of the new genera Lachancea, Nakaseomyces, Naumovia, Vanderwaltozyma and Zygotorulaspora

Genera currently assigned to the Saccharomycetaceae have been defined from phenotype, but this classification does not fully correspond with species groupings determined from phylogenetic analysis of gene sequences. The multigene sequence analysis of Kurtzman and Robnett [FEMS Yeast Res. 3 (2003) 417-432] resolved the family Saccharomycetaceae into 11 well-supported clades. In the present study, the taxonomy of the Saccharomyctaceae is evaluated from the perspective of the multigene sequence analysis, which has resulted in reassignment of some species among currently accepted genera, and the proposal of the following five new genera: Lachancea, Nakaseomyces, Naumovia, Vanderwaltozyma and Zygotorulaspora.     

Immunization with a tumor-cell-lysate-loaded autologous-antigen-presenting-cell-based vaccine in melanoma

The discoveries of human melanoma-associated antigens in molecular terms have renewed interest in peptide- or peptide- and antigen-presenting-cell (APC)-based cancer vaccines. Considering the limited scope of immunization using defined peptides, we have studied an alternative approach of specific immunization with tumor-lysate-loaded autologous APC (adherent peripheral mononuclear cells cultured in 1000 U granulocyte/macrophage-colony-stimulating factor for 14 days) as a surrogate vaccine. Seventeen patients (11 with active metastatic disease) were intradermally immunized with the vaccine in a phased dose escalation (10⁵–10⁷ cells/injection) monthly for 4 months. Thirteen patients completed all four immunizations showing no toxicity (3 patients had to be taken off study because of progressive disease and 1 patient went off study as a result of myocardial infarction due to multi-vessel coronary artery disease). None has shown any immediate or delayed toxicity attributable to the immunization and none has shown any evidence of autoimmunity. One patient showed a partial regression of a subcutaneous nodule. Thirteen patients are alive after 4+ months to 30+ months (17-month median survival for the group). Nine patients showed evidence of delayed-type hypersensitivity at the vaccine sites. Monitoring of biological response in conventional natural killer or cytolytic T lymphocyte assays with pre- and post-immune peripheral blood lymphocytes revealed no consistent differences. The vaccine-infiltrating lymphocytes (VIL) from nine specimens were adequately expanded following in vitro stimulation with the respective autologous-lysate-loaded APC for phenotypic and functional analyses. Five of the nine ex vivo expanded VIL were predominantly CD8⁺. Evidence of an antigen-specific CD8⁺ T cell response (cytotoxicity and/or tumor necrosis factor production) was detected in three of the five CD8⁺ VIL. These observations suggest that this type of vaccine is feasible, that it has biological activity, and that the approach may be improved through additional strategic manipulations. Received: 27 March 1998 / Accepted: 14 May 1998     

Candida shehatae — Genetic diversity and phylogenetic relationships with other xylose-fermenting yeasts

The xylose-fermenting yeasts Candida shehatae and Pichia stipitis were compared from extent of nuclear DNA complementarity and ribosomal RNA sequence similarity. Low levels of DNA relatedness confirmed that the two taxa are distinct biological species, but the similarity of rRNA sequences suggests that they only recently diverged. C. shehatae is comprised of three genetically divergent (ca. 50% DNA relatedness) subgroups that were accorded varietal status: C. shehatae var. shehatae, var. Lignosa and var. insectosa. Estimates of phylogenetic distance from rRNA sequence similarity show C. shehatae and P. stipitis to be more closely related to Pachysolen tannophilus than to Saccharomyces cerevisiae, and that all of these budding yeasts are well separated from Schizosaccharomyces pombe.     

Cloning of zebrafish vsx1: Expression of a paired-like homeobox gene during CNS development

vsx1 is a homeobox gene encoding a paired-type homeodomain and a CVC domain that was originally cloned from an adult goldfish retinal library. We previously reported the spatiotemporal expression pattern of vsx1in the adult and developing retina of zebrafish and goldfish, and we suggested that vsx1 plays a role in determining the cell fate and maintenance of retinal interneurons. Other related genes encoding a CVC domain, such as vsx2 (alx) and chx10, are expressed both within and outside the retina during development. In this study, we report the cloning of zebrafish vsx1 and its developmental expression in both retinal and nonretinal regions of the CNS in zebrafish embryos. vsx1expression was detected in a subset of hindbrain and spinal cord neurons before it was expressed in the retina. At about the same time that retinal expression began, the level of vsx1 was decreased in the spinal cord. The expression of vsx1 was progressively restricted, and eventually it was detected only in the inner nuclear layer (INL) of the developing retina. The combined expression patterns of teleost vsx1 and vsx2 (alx) during early zebrafish development encompasses the expression pattern observed for murine Chx10, and indicates a partitioning of function for CVC genes in lower vertebrates. Dev. Genet. 23:128–141, 1998. © 1998 Wiley-Liss, Inc.