Molecular manipulation of the mating-type system and development of a new approach for characterizing pathogen virulence in Pyrenophora tritici-repentis

ABSTRACT Selfing clones of Tetrahymena pigmentosa show several interesting genetic features, and provide some insight into the mechanisms of mating type (mt) determination. They differ significantly from those of Tetrahymena thermophila. They are distributed nonrandomly in crosses. Their rates of stabilization are highly variable, but most are much lower than those reported for T. thermophila. A number of subclones derived from nearly all the selfers have maintained stable mts in culture for several years. However, some subclones manifest persistent selfing, long after the calculated completion of allelic assortment for heterozygous loci. This phenomenon along with the perpetual maintenance of dominant mts in heterozygotes shows that phenotypic assortment is not involved in mt expression.—In crosses, many selfers exhibit quantitative and qualitative aberrations in the transmission of alleles to the gametes; some of the micronuclear changes underlying these aberrations occur during vegetative growth. There are rare illegitimate appearances of dominant alleles in sexual progeny, and more common illegitimate appearances of the most recessive phenotype.—Various models to explain mt determination in this species are considered. One which might account for the troubling phenomena of the system consists of an active mat expression site, with "cassettes" at other sites specific for the different dominant alleles and capable of transposition to the expression site.

Download Full-text

Global variables in Haskell

Journal of Functional Programming ◽

10.1017/s0956796802004471 ◽

2004 ◽

Vol 14 (5) ◽

pp. 489-502 ◽

Cited By ~ 2

Author(s):

JOHN HUGHES

Keyword(s):

Graph Algorithms ◽

Functional Programming ◽

Type System ◽

Web Servers ◽

New Approach ◽

Global Variables ◽

Global Variable ◽

Good Support

Haskell today provides good support not only for a functional programming style, but also for an imperative one. Elements of imperative programming are needed in applications such as web servers, or to provide efficient implementations of well-known algorithms, such as many graph algorithms. However, one element of imperative programming, the global variable, is surprisingly hard to emulate in Haskell. We discuss several existing methods, none of which is really satisfactory, and finally propose a new approach based on implicit parameters. This approach is simple, safe, and efficient, although it does reveal weaknesses in Haskell's present type system.

Download Full-text

Genetic regulation of differentiation towards meiosis in the yeast Saccharomyces cerevisiae

Genome ◽

10.1139/g89-018 ◽

1989 ◽

Vol 31 (1) ◽

pp. 95-99 ◽

Cited By ~ 6

Author(s):

Giora Simchen ◽

Yona Kassir

Keyword(s):

Saccharomyces Cerevisiae ◽

Protein Kinase ◽

Adenylate Cyclase ◽

Mating Type ◽

Genetic Regulation ◽

Type System ◽

Yeast Saccharomyces Cerevisiae ◽

Regulatory Pathways ◽

Early Expression ◽

Kinase Pathway

Normally, meiosis and sporulation in Saccharomyces cerevisiae occur only in diploid strains and only when the cells are exposed to starvation conditions. Diploidy is determined by the mating-type system (the genes MAT, RME1, IME1), whereas the starvation signal is transmitted through the adenylate cyclase – protein kinase pathway (the genes CDC25, RAS2, CDC35 (CYR1), BCY1, TPK1, TPK2, TPK3). The two regulatory pathways converge at the gene IME1, which is a positive regulator of meiosis and whose early expression in sporulating cells correlates with the initiation of meiosis. Sites upstream (5′) of IME1 appear to mediate in the repression of the gene by repressors originating from both the mating-type and the cyclase – kinase pathways.Key words: sporulation, mating type, diploidy, adenylate cyclase, cAMP, protein kinase.

Download Full-text

The Mating Type System of the Myxomycete Physarum flavicomum

Mycologia ◽

10.2307/3757093 ◽

1967 ◽

Vol 59 (4) ◽

pp. 637 ◽

Cited By ~ 14

Author(s):

Mary R. Henney

Keyword(s):

Mating Type ◽

Type System

Download Full-text

A Mating-type System in an Acellular Slime-mould

Nature ◽

10.1038/185780a0 ◽

1960 ◽

Vol 185 (4715) ◽

pp. 780-781 ◽

Cited By ~ 51

Author(s):

JENNIFER DEE

Keyword(s):

Mating Type ◽

Type System ◽

Slime Mould

Download Full-text

The mating type system of the rare polypore Hapalopilus croceus

Fungal Ecology ◽

10.1016/j.funeco.2020.100941 ◽

2020 ◽

Vol 45 ◽

pp. 100941

Author(s):

Deanne Redr ◽

Anders Dahlberg ◽

Jan Stenlid ◽

Stellan Sunhede ◽

Rimvydas Vasaitis ◽

...

Keyword(s):

Mating Type ◽

Type System

Download Full-text

Nonlinear Parametric System Identification Using Hard Excitations

Volume 2: Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting ◽

10.1115/smasis2016-9075 ◽

2016 ◽

Author(s):

Abdraouf Abusoua ◽

Mohammed F. Daqaq

Keyword(s):

Good Accuracy ◽

Type System ◽

Parametric Identification ◽

Identification Procedure ◽

Nonlinear Parameters ◽

New Approach ◽

Experimental Systems ◽

High Frequency Excitation ◽

Frequency Excitation ◽

Quadratic And Cubic Nonlinearities

This paper presents a new approach for the parametric identification of nonlinear systems. The approach is based on subjecting a nonlinear system to a strong high-frequency excitation and monitoring its influence on the slow modulation of the system’s response which occurs near its natural frequency. The identification procedure is outlined and numerically implemented on a Duffing-type system with unknown quadratic and cubic nonlinearities. The proposed technique is then implemented to identify the nonlinear parameters of three different experimental systems. Results demonstrate that the proposed approach predicts the nonlinear parameters with good accuracy.

Download Full-text

Polyphasic re-examination of Yarrowia lipolytica strains and the description of three novel Candida species: Candida oslonensis sp. nov., Candida alimentaria sp. nov. and Candida hollandica sp. nov.

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.65200-0 ◽

2007 ◽

Vol 57 (10) ◽

pp. 2426-2435 ◽

Cited By ~ 45

Author(s):

Ann Kristin Knutsen ◽

V. Robert ◽

G. A. Poot ◽

Wendy Epping ◽

Marian Figge ◽

...

Keyword(s):

Yarrowia Lipolytica ◽

Mating Type ◽

Type Strain ◽

Sequence Data ◽

Type System ◽

Sensu Stricto ◽

Rrna Gene ◽

Dna Reassociation ◽

D2 Domain ◽

26S Rrna

The type strain of Yarrowia lipolytica and 38 strains identified as Yarrowia lipolytica, four strains of Candida deformans, including the type and two subcultures of the type, two strains of Candida galli and six unidentified strains that resembled Y. lipolytica were examined by PCR fingerprints using primers M13 and (GAC)5. The same strains, together with four strains of the recently introduced Candida yakushimensis nom. inval., were sequenced for the D1/D2 domain of the 26S rRNA gene and parts of the ITS domain and also studied for their physiological properties. Of the strains identified previously as Y. lipolytica, CBS 2076 had the same fingerprint as the type of C. deformans and strain CBS 4855 was distinct from all other strains. The six strains that resembled Y. lipolytica were separated into two groups distinct from any of the other clades. A total of six groups obtained by fingerprint and sequence data were evaluated by performing DNA reassociation reactions. Mating experiments among the 35 strains of Y. lipolytica sensu stricto showed that 15 strains represented one mating type and 16 strains represented the opposite mating type, while four strains were self-sporulating. Teleomorph states were not produced by C. deformans, C. galli or any of the unidentified isolates. However, positive mating reactions were rarely observed in crosses among C. galli and some strains of Y. lipolytica and C. deformans. Consequently, sharing the same mating type system, C. deformans and C. galli could be considered anamorphs of unnamed Yarrowia species. Results from PCR fingerprints, sequencing and mating studies support the grouping of the studied strains into Y. lipolytica, C. galli, C. deformans, C. yakushimensis nom. inval. and three novel species in the Yarrowia clade: Candida oslonensis sp. nov. (type strain CBS 10146T =NRRL Y-48252T; Mycobank number MB 510769), Candida alimentaria sp. nov. (type strain CBS 10151T =NRRL Y-48253T; Mycobank number MB 510770) and Candida hollandica sp. nov. (type strain CBS 4855T =NRRL Y-48254T; Mycobank number MB 510771).

Download Full-text