scholarly journals Modification of Sexual Development and Carotene Production by Acetate and Other Small Carboxylic Acids in Blakeslea trispora and Phycomyces blakesleeanus

2006 ◽  
Vol 72 (7) ◽  
pp. 4917-4922 ◽  
Author(s):  
Vera Kuzina ◽  
Enrique Cerdá-Olmedo
Keyword(s):  
Carboxylic Acids ◽  
Sexual Development ◽  
Minimal Medium ◽  
Sexual Cycle ◽  
Blakeslea Trispora ◽  
Common Mechanism ◽  
Maximal Effect ◽  
Phycomyces Blakesleeanus ◽  
Sexual Interaction ◽  
Solid Substrates

ABSTRACT In Phycomyces blakesleeanus and Blakeslea trispora (order Mucorales, class Zygomycetes), sexual interaction on solid substrates leads to zygospore development and to increased carotene production (sexual carotenogenesis). Addition of small quantities of acetate, propionate, lactate, or leucine to mated cultures on minimal medium stimulated zygospore production and inhibited sexual carotenogenesis in both Phycomyces and Blakeslea. In Blakeslea, the threshold acetate concentration was <1 mmol/liter for both effects, and the concentrations that had one-half of the maximal effect were <2 mmol/liter for carotenogenesis and >7 mmol/liter for zygosporogenesis. The effects on Phycomyces were similar, but the concentrations of acetate had to be multiplied by ca. 3 to obtain the same results. Inhibition of sexual carotenogenesis by acetate occurred normally in Phycomyces mutants that cannot use acetate as a carbon source and in mutants whose dormant spores cannot be activated by acetate. Small carboxylic acids may be signals that, independent of their ability to trigger spore germination in Phycomyces, modify metabolism and development during the sexual cycle of Phycomyces and Blakeslea, uncoupling two processes that were thought to be linked and mediated by a common mechanism.

scholarly journals Intersexual Partial Diploids of Phycomyces

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 635-641
Author(s):  
Bina J Mehta ◽  
Enrique Cerdá-Olmedo
Keyword(s):  
Dry Mass ◽  
Sexual Cycle ◽  
Genetic Constitution ◽  
Phycomyces Blakesleeanus ◽  
Carotene Content ◽  
Sexual Interaction ◽  
Sexual Stimulation ◽  
Nuclear Composition ◽  
Opposite Sex ◽  
Β Carotene

Abstract Sexual interaction between strains of opposite sex in many fungi of the order Mucorales modifies hyphal morphology and increases the carotene content. The progeny of crosses of Phycomyces blakesleeanus usually include a small proportion of anomalous segregants that show these signs of sexual stimulation without a partner. We have analyzed the genetic constitution of such segregants from crosses that involved a carF mutation for overaccumulation of β-carotene and other markers. The new strains were diploids or partial diploids heterozygous for the sex markers. Diploidy was unknown in this fungus and in the Zygomycetes. Random chromosome losses during the vegetative growth of the diploid led to heterokaryosis in the coenocytic mycelia and eventually to sectors of various tints and mating behavior. The changes in the nuclear composition of the mycelia could be followed by selecting for individual nuclei. The results impose a reinterpretation of the sexual cycle of Phycomyces. Some of the intersexual strains that carried the carF mutation contained 25 mg β-carotene per gram of dry mass and were sufficiently stable for practical use in carotene production.

Phagocytic specificity during sexual development in Dictyostelium discoideum

1986 ◽  
Vol 32 (2) ◽  
pp. 79-82 ◽  
Author(s):  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Concanavalin A ◽  
Sexual Development ◽  
Wheat Germ ◽  
Giant Cells ◽  
Inhibitory Effect ◽  
Sexual Cycle ◽  
Type I ◽  
Further Development ◽  
Type Receptor

During the sexual cycle of Dictyostelium discoideum, zygote giant cells develop and serve as foci for further development by chemoattracting and cannibalizing hundreds of local amoebae. Previous work has shown that the phagocytic process bears similarities to and differences from asexual endocytosis. In the present study, sexual phagocytosis in D. discoideum was found to be species and developmental stage specific. It was inhibited selectively by glucose and concanavalin A. Although a partial, inhibitory effect of mannose on phagocytosis was not statistically significant, alpha-methylmannosamine, like alpha-methyl-glucose, significantly restored the phagocytic competence of giant cells treated with concanavalin A. Other sugars (N-acetyl glucosamine, N-acetylgalactosamine, and galactose) and lectins (wheat germ agglutinin, Ulex europus type I, and Ricinis communis agglutinin type I) had no significant effect on sexual phagocytosis. Together these data indicate that a glucose-type receptor is involved in selective uptake of D. discoideum amoebae by giant cells.

scholarly journals Sex-Specific Homeodomain Proteins Sxi1α and Sxi2a Coordinately Regulate Sexual Development in Cryptococcus neoformans

2005 ◽  
Vol 4 (3) ◽  
pp. 526-535 ◽  
Author(s):  
Christina M. Hull ◽  
Marie-Josee Boily ◽  
Joseph Heitman
Keyword(s):  
Cryptococcus Neoformans ◽  
Sexual Development ◽  
Expression Patterns ◽  
Regulatory Protein ◽  
Control Cell ◽  
Sexual Cycle ◽  
Homeodomain Protein ◽  
Homeodomain Proteins ◽  
Human Fungal Pathogen ◽  
Cell Type Specific

ABSTRACT Homeodomain proteins are central regulators of development in eukaryotes. In fungi, homeodomain proteins have been shown to control cell identity and sexual development. Cryptococcus neoformans is a human fungal pathogen with a defined sexual cycle that produces spores, the suspected infectious particles. Previously, only a single homeodomain regulatory protein involved in sexual development, Sxi1α, had been identified. Here we present the discovery of Sxi2a, a predicted but heretofore elusive cell-type-specific homeodomain protein essential for the regulation of sexual development. Our studies reveal that Sxi2a is necessary for proper sexual development and sufficient to drive this development in otherwise haploid α cells. We further show that Sxi1α and Sxi2a interact with one another and impart similar expression patterns for two key mating genes. The discovery of Sxi2a and its relationship with Sxi1α leads to a new model for how the sexual cycle is controlled in C. neoformans, with implications for virulence.

Apocarotenoids in the sexual interaction of Phycomyces blakesleeanus

2012 ◽  
Vol 10 (15) ◽  
pp. 3002 ◽  
Author(s):  
Silvia Polaino ◽  
Jose A. Gonzalez-Delgado ◽  
Pilar Arteaga ◽  
M. Mar Herrador ◽  
Alejandro F. Barrero ◽  
...  
Keyword(s):  
Phycomyces Blakesleeanus ◽  
Sexual Interaction

scholarly journals A Mutant Defective in Sexual Development Produces Aseptate Ascogonia

2010 ◽  
Vol 9 (12) ◽  
pp. 1856-1866 ◽  
Author(s):  
Sandra Bloemendal ◽  
Kathryn M. Lord ◽  
Christine Rech ◽  
Birgit Hoff ◽  
Ines Engh ◽  
...  
Keyword(s):  
Sexual Development ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Sexual Cycle ◽  
Sequence Analyses ◽  
Gene Encoding ◽  
Content Type ◽  
Domain Of Unknown Function ◽  
Sterile Mutant

ABSTRACT The transition from the vegetative to the sexual cycle in filamentous ascomycetes is initiated with the formation of ascogonia. Here, we describe a novel type of sterile mutant from Sordaria macrospora with a defect in ascogonial septum formation. This mutant, named pro22, produces only small, defective protoperithecia and carries a point mutation in a gene encoding a protein that is highly conserved throughout eukaryotes. Sequence analyses revealed three putative transmembrane domains and a C-terminal domain of unknown function. Live-cell imaging showed that PRO22 is predominantly localized in the dynamic tubular and vesicular vacuolar network of the peripheral colony region close to growing hyphal tips and in ascogonia; it is absent from the large spherical vacuoles in the vegetative hyphae of the subperipheral region of the colony. This points to a specific role of PRO22 in the tubular and vesicular vacuolar network, and the loss of intercalary septation in ascogonia suggests that PRO22 functions during the initiation of sexual development.

scholarly journals Elucidation of the determinant for orchestration of solo unisexual cycle in an important human fungal pathogen

2019 ◽  
Author(s):  
Pengjie Hu ◽  
Huimin Liu ◽  
Lei Chen ◽  
Guang-Jun He ◽  
Xiuyun Tian ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sexual Development ◽  
Fungal Pathogen ◽  
Model Organism ◽  
Sexual Cycle ◽  
Critical Determinant ◽  
Human Fungal Pathogen ◽  
Alternative Approach ◽  
Sexual Determination ◽  
Functional Profiling

AbstractIn fungi, the sex-determination program universally directs sexual development and syngamy (the fusion of gametes) that underlies pre-meiotic diploidization. However, the contribution of sex-determination to syngamy-independent sexual cycle, which requires autopolyploidization as an alternative approach to elevate ploidy before meiosis, remains unclear in fungi and other eukaryotes. The human fungal pathogen Cryptococcus neoformans, as a model organism for studying fungal sexual reproduction, can undergo syngamy-dependent bisexual and syngamy-independent solo unisexual reproduction, in which endoreplication is considered to enable pre-meiotic self-diploidization. Here, by characterizing a mutant lacking all the core sex-determination factors, we show that sex-determination plays a central role in bisexual syngamy but is not strictly required for unisexual development and self-diploidization. This implies an unknown circuit, rather than the sex-determination program, for specifically coordinating Cryptococcus unisexual cycle. We reveal that syngamy and self-diploidization are both governed by the Qsp1-directed paracrine system via two regulatory branches, Vea2 and Cqs2. Vea2 directs bisexual syngamy through the sex-determination program; conversely, Cqs2 is dispensable for bisexual syngamy but activates unisexual endoreplication. Through functional profiling of 41 transcription factors documented to regulate Cryptococcus sexual development, we reveal that only Cqs2 can drive and integrate all unisexual phases and ensure the production of meiospore progenies. Furthermore, ChIP-seq analysis together with genetic evaluation indicate that Cqs2 induces unisexual self-diploidization through its direct control of PUM1, whose expression is sufficient to drive autopolyploidization. Therefore, Cqs2 serves as the critical determinant that orchestrates Cryptococcus multistage unisexual cycle that does not strictly require the sexual-determination program.

scholarly journals Methionine Induces Sexual Development in the Fission Yeast Schizosaccharomyces pombe via anste11-Dependent Signalling Pathway

1998 ◽  
Vol 180 (23) ◽  
pp. 6338-6341 ◽  
Author(s):  
Anne-Marie Schweingruber ◽  
Norma Hilti ◽  
Eleonore Edenharter ◽  
M. Ernst Schweingruber
Keyword(s):  
Cyclic Amp ◽  
Stationary Phase ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Sexual Development ◽  
Minimal Medium ◽  
Signalling Pathway ◽  
Intracellular Camp

ABSTRACT Methionine added to minimal medium overcomes the repressing effects of ammonium and cyclic AMP (cAMP) on sexual development and efficiently induces mating and sporulation in homothallic strains ofSchizosaccharomyces pombe. In heterothallic strains it induces G1 arrest when cells enter stationary phase. We show that methionine reduces the intracellular cAMP pool and induces the expression of at least two cAMP-repressible genes, includingfbp1 and ste11. The easiest interpretation of the results is that methionine induces sexual development via a cAMP-dependent ste11 signalling pathway.

scholarly journals Sexuality in Neurospora crassa II. Genes affecting the sexual development cycle

1972 ◽  
Vol 19 (3) ◽  
pp. 205-211 ◽  
Author(s):  
N. V. Vigfusson ◽  
J. Weijer
Keyword(s):  
Neurospora Crassa ◽  
Sexual Development ◽  
Sexual Cycle ◽  
Male Sterile ◽  
Early Stages ◽  
Comparison Of Results ◽  
Development Cycle

SUMMARYEighteen male sterile mutants of N. crassa which block various stages of the sexual development cycle have been functionally categorized on the basis of complementation tests. Nine of these (those which block early stages of the sexual cycle) have also been analysed through recombination studies. On the basis of these data, a minimum of four genes appear to be involved in early stages of sexual development (i.e. probably prior to karyogamy) and several genes are indicated which control later stages of the cycle. Complementation phases with respect to sexual development in heterothallic Ascomycetes are discussed as well as a comparison of results obtained with expectations and with those obtained in related Ascomycetes.

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