Edward D. Garber

Genetics of Ustilago violacea - XXI. Centromere-linkage values and pericentric gene clustering

SummaryLimited enrichment medium using seven different complex media and screening only small to very small sporidial colonies for auxotrophic mutants was more efficient and less tedious than replica-plating in obtaining a large collection of mutants with different phenotypes. Centromere-linkage values (CLVs) of 48 auxotrophic mutations were obtained by half-tetrad analysis and ranged from 0.5 cM to 31.3 cM and approximately 70% of the CLVs were within 10 cM of the centromere. Inocula of mutants with the same phenotype were either pathogenic or nonpathogenic depending on the availability of compounds in host-tissue required by the auxotrophic hyphae. Colonial morphology mutants included strains that gave diploid or aneuploid sporidia from teliospore colonies, indicating a relationship between the morphology mutation and meiotic nondisjunction.

Proteins and enzymes as taxonomic tools.

Publisher Summary According to the International Code of Nomenclature, organisms must be assigned to a species. When an organism is to be named, a dossier of its characteristics is prepared to determine whether the organism has already been described. If the organism does not fit into an already described species, it must be described to receive recognition as a “new” species according to the appropriate code. This ritual constitutes a memorial to Linnaeus who created order in the previously chaotic classification of plant and animal macroorganisms. In the beginning, microbial classification followed Linnaean protocol. Although considerable progress has been made in the preparation of increasingly more sophisticated dossiers, the microbial taxonomist seems to have produced increasingly greater Linnaean chaos in certain groups. Perhaps the situation is best appreciated by considering an opinion offered by a macrobial taxonomist. Whatever other functions may be attributed to taxonomy—such as investigating phylogeny, the creation of a data storage and retrieval agency is surely an inescapable one.

Characterization of carotene accumulation inUstilago violacea using high-performance liquid chromatography

Quantitative analysis of carotene accumulation in white, pink, pumpkin, orange, and yellow haploid strains ofUstilago violacea by high-performance liquid chromatography indicated that specific patterns of carotene accumulation are primarily responsible for the white, pumpkin, orange, and yellow phenotypes. The yellow strains accumulated primarily β-zeacarotene and β-carotene. The white strains accumulated primarily the colorless carotene, phytoene, or did not accumulate any carotene at all. Carotene accumulation in pink haploid strains followed the same patterns as for the white, pumpkin, orange, or yellow strains. Pink diploid and disomic strains ofU. violacea with various parental combinations of the color mutations accumulated either cis-β-zeacarotene and β-carotene or only β-carotene. The pattern of carotene accumulation in conjunction with the available genetic information for the carotene loci inU. violacea was used as a basis for the construction of a new genetic model for carotene biosynthesis inU. violacea. The model employs three dehydrogenases and one cyclase for the synthesis of β-carotene from phytoene, and accounts for the carotene accumulation patterns of either cis-β-zeacarotene and β-carotene or lycopene, γ-carotene, and β-carotene.

Characterization of the pigment in pink sporidial colonies of Ustilago violacea as cytochrome c

The pigment of a pink strain of Ustilago violacea 1.C429 was associated with the mitochondria isolated on a sucrose gradient. The extracted red pigment was identified as cytochrome c by spectral analysis and by oxidation with cytochrome c oxidase from rat liver mitochondria. The pink strain accumulated at least tenfold more cytochrome c than a white strain. Zn2+ enhanced cytochrome c production in a white strain by 75%.

Characterization of cytochrome c accumulation in white and pink strains ofUstilago violacea using low-temperature spectroscopy and amino acid analysis

The extent of cytochrome c accumulation in 46 pink and white strains ofUstilago violacea was determined using low-temperature spectroscopy. Pink strains accumulated approximately 14 times more cytochrome c than white strains. Cytochrome c was extracted and purified from two pink (2A2, 1.C429) and two white (15.10, 900-42.1) strains ofU. violacea and subjected to amino acid analysis. One pink (2A2) and one white (15.10) strain were genetically related; the others (900-42.1, 1.C429) were not. One white strain (900-42.1) contained spectrally distinct cytochrome c. Comparisons of the amino acid compositions of the cytochrome c from these four strains ofU. violacea using divergence calculations and computer-assisted cluster analysis indicated a high degree of relatedness for the two pink strains, a moderate degree of relatedness for the pink strains and white strain 15.10, and a low degree of relatedness for white strain 900-42.1 with the others. These results support the hypothesis that there are two distinct cytochrome c loci inU. violacea.

The genetics and biochemistry of urease in Ustilago violacea.

Two complementing loci in different linkage groups of the basidiomycete Ustilago violacea are involved in urease activity: a structural one (ure-1) and a second inferred to involve a permease (ure-2) locus. Two types of complementing mutations occur in the structural locus: null activity (ure-1a) and obviously reduced activity (ure-1b). The ure-2 mutants lacked urease activity in vivo on the phenol red-urea test medium, but gave extracts with wild-type activity. Extracts from wild-type strains gave one site of urease activity after polyacrylamide gel electrophoresis. A number of ure-1b mutants and active revertants from ure-1a mutants yielded electrophoretically variant urease sites. The results are discussed in terms of enzyme polymorphism in haploid eukaryotes by one (missense) or two (null, then missense) mutations.

Spontaneous and induced mitotic recombination in Ustilago violacea detected at the cellular level

SummarySpontaneous and induced mitotic recombination in the heterobasidiomycete Ustilago violacea was detected at the cellular level using a sporidial morphology mutation. Mitotic recombination was induced by ultraviolet light (UV), nitrogen mustard (NM) and metabolically nonactivated cyclophosphamide (CP). The effects of low (14 °C) and high (30 °C) temperature and culture age on induced mitotic recombination are reported. Low temperature after inductive treatment uniformly reduced mitotic recombination. High temperature increased UV induced recombination, had no effect on NM-induced recombination and reduced CP-induced recombination to the spontaneous level. Temperature alone had no effect on mitotic recombination. Ultraviolet light-induced recombination was correlated with the rate of cell division and cell survival as cells passed from log to stationary phase growth. Detection of mitotic recombination at the cellular level is discussed as a method to assay postreplication repair of genetic damage and as a screen for agents which induce genetic damage in eukaryotic cells.

Purification and amino acid analysis of cytochrome c fromUstilago violacea

Cytochrome c fromUstilago violacea was further analyzed in order to characterize the pink phenotype. NaOH-extracted cytochrome c was purified in three steps, which included ammonium sulfate precipitation, CM-Sephadex ion-exchange chromatography with 0.5 N NaCl elution, and CM-Sephadex ion-exchange chromatography with a 0.0–0.6 N NaCl gradient elution. Polyacrylamide gel electrophoresis of the purified protein yielded a single red band, which was the only band detected upon Coumassie brilliant blue staining. HCl-hydrolysates of the protein were examined for their amino acid composition, which indicated that the cytochrome c fromU. violacea contains approximately 104 residues, with high levels of alanine, histidine, serine, and low levels of phenylalanine and arginine.

Chemotaxonomy of the Oscillatoria-Phormidium complex☆

Abstract Five species of Phormidium and eight species of Oscillatoria were compared in terms of carotenoids, biliproteins, protein profiles and α-esterases, leucine aminopeptidase and phosphatase zymograms. The data from protein profiles and α-esterase zymograms support morphological criteria in recognizing four groups of conspecific taxa: O. tenuis, O. amoena , and O. animalis; O. chalybea and O. formosa; P. foveolarum and P. luridum var. olivacea ; and P. persicinum and P. ectocarpii . Problems of Cyanophycean taxonomy are considered in terms of biochemical adjuncts to conventional criteria in characterizing and distinguishing species.