The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Robert L. Metzenberg - One of the best experts on this subject based on the ideXlab platform.
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A Putative Rhamnogalacturonase Required for Sexual Development of Neurospora crassa
Genetics, 1997Co-Authors: Mary Anne Nelson, Sandra T. Merino, Robert L. MetzenbergAbstract:In previous work, the asd-1 (ascus Development) gene of the filamentous fungus Neurospora crassa was identified as a gene expressed preferentially during the Sexual cycle and shown to be essential for normal Sexual Development. The asd-1 gene has been sequenced and further characterized. It contains two introns, the first of which is in-frame and inefficiently or differentially spliced. The predicted ASD-1 protein has extensive homology with rhamnogalacturonase B of Aspergillus aculeatus, which cleaves the backbone within the ramified hairy regions of pectin. In homozygous asd-1 crosses, Sexual Development is initiated and large numbers of normal-sized asci are formed. Ascospore delineation does not occur, however, and no Sexual progeny are produced. As most asd-1 asci contain eight nuclei, the two meiotic divisions and subsequent mitotic division typical of normal crosses seem to occur, but the haploid nuclei are not partitioned into ascospores. In wild-type crosses, the ASD-1 protein is present in large amounts in croziers and young asci, but it is only faintly detectable in more mature asci containing developing ascospores. Models to explain the possible role of a rhamnogalacturonase in Sexual Development are presented.
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Sexual Development genes of Neurospora crassa.
Genetics, 1992Co-Authors: M A Nelson, Robert L. MetzenbergAbstract:The filamentous fungus Neurospora crassa undergoes a complex program of Sexual Development to form a fruiting body composed of several kinds of specialized tissue. Subtractive hybridization was used to isolate genes that are expressed preferentially during this Sexual phase. Many such Sexual Development (sdv) genes were identified in a cosmid library of Neurospora genomic DNA. Fourteen of the sdv genes were subcloned, and their expression in mutant strains and under crossing and vegetative growth conditions was examined. All of the regulated transcripts were less abundant (and in many cases not detectable) in strains grown under vegetative (high nitrogen) conditions, suggesting that nitrogen starvation is required for their synthesis. The expression of most of the sdv genes also required a functional A mating type product, even under crossing growth conditions, suggesting that this product functions as a master control in Sexual Development. To determine if the products of the sdv genes play essential roles in the Sexual cycle, a reverse-genetic approach (based on RIP (repeat-induced point mutation)-mediated gene disruptions) was used to create mutations in the genes. A mutant strain (asd-1) with a recessive crossing defect (apparently caused by the RIP process) was isolated; in this strain, early Development is normal and may asci are formed, but ascospores are never delineated. A second recessive mutant strain (asd-2) was apparently created by ectopic integration of the transforming DNA into a gene required for the Sexual process; in this strain the Sexual process was blocked at an early stage, and the ascogeneous tissue underwent little Development.
Rinus Wiersma - One of the best experts on this subject based on the ideXlab platform.
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The clinical spectrum and treatment of ovotesticular disorder of Sexual Development.
Advances in experimental medicine and biology, 2011Co-Authors: Rinus WiersmaAbstract:In general practice worldwide, disorder of Sexual Development (DSD) is an uncommon condition. Although the proportions of individual conditions making up the spectrum of DSD vary from country to country, ovotesticular disorder of Sexual Development (OT-DSD) is regarded as a rare type, constituting between 3 and 10% of the total DSD [1].
Christina M. Hull - One of the best experts on this subject based on the ideXlab platform.
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Transcriptional control of Sexual Development in Cryptococcus neoformans
Journal of Microbiology, 2016Co-Authors: Matthew E. Mead, Christina M. HullAbstract:Developmental processes are essential for the normal life cycles of many pathogenic fungi, and they can facilitate survival in challenging environments, including the human host. Sexual Development of the human fungal pathogen Cryptococcus neoformans not only produces infectious particles (spores) but has also enabled the evolution of new disease-related traits such as drug resistance. Transcription factor networks are essential to the Development and pathogenesis of C. neoformans , and a variety of sequence-specific DNA-binding proteins control both key Developmental transitions and virulence by regulating the expression of their target genes. In this review we discuss the roles of known transcription factors that harbor important connections to both Development and virulence. Recent studies of these transcription factors have identified a common theme in which metabolic, stress, and other responses that are required for Sexual Development appear to have been co-opted for survival in the human host, thus facilitating pathogenesis. Future work elucidating the connection between Development and pathogenesis will provide vital insights into the evolution of complex traits in eukaryotes as well as mechanisms that may be used to combat fungal pathogens.
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Formulation of a Defined V8 Medium for Induction of Sexual Development of Cryptococcus neoformans
Applied and environmental microbiology, 2008Co-Authors: Cory R. Kent, Patricia Ortiz-bermúdez, Steven S. Giles, Christina M. HullAbstract:For over 3 decades, Sexual Development in the human fungal pathogen Cryptococcus neoformans and other fungi has been initiated by growing compatible mating partners on V8 juice medium. Although this medium is an efficient inducer of Sexual Development, the mechanism by which it promotes the process is unknown. To understand how V8 juice medium induces Sexual Development, we attempted to purify inducing factors from V8 juice, and we carried out a complete compositional analysis of V8 juice. We discovered that no single factor is responsible for the effects of V8 juice medium. Rather, the unique composition of V8 juice medium provides the proper nutrient composition for inducing and sustaining complete Sexual Development. Utilizing these findings, we developed a defined V8 (DV8) medium that mimics V8 juice medium in Sexual Development assays. Then, using DV8 as a tool, we explored the roles that specific molecules play in enhancing Sexual Development. Surprisingly, we discovered that copper is a key factor, leading to an upregulation of the mating pheromone genes MFa and MFα, both required for the initial steps in Sexual Development. The utilization of DV8 to investigate the effects of copper on Sexual Development presented here is an example of how defining the conditions that induce Sexual Development will advance the study of C. neoformans.
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Sex-Specific Homeodomain Proteins Sxi1α and Sxi2a Coordinately Regulate Sexual Development in Cryptococcus neoformans
Eukaryotic cell, 2005Co-Authors: Christina M. Hull, Marie-josee Boily, Joseph HeitmanAbstract: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.
S.i. Turchina - One of the best experts on this subject based on the ideXlab platform.
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Zinc and somato-Sexual Development of adolescents
INTERNATIONAL JOURNAL OF ENDOCRINOLOGY, 2017Co-Authors: S.i. TurchinaAbstract:Background. The study investigated the age changes of zinc (Zn) in pubertal boys and its changes in delayed growth and Sexual Development. The aim of the study was to expand existing concepts about the influence of Zn deficiency disorders on the physical and Sexual Development in adolescents. Materials and methods. In 70 adolescent boys aged 10–17 years Zn level was evaluated, taking into account somato-Sexual Development and the presence of diffuse nontoxic goiter (DNG). Teens were divided into groups: 1) 20 boys aged 10–17 years with normal volume of the thyroid gland, normal physical and Sexual Development; 2) 17 adolescents aged 14–17 years with normal Sexual Development and DNG; 3) 15 adolescents aged 14–17 years with Sexual development delay (SDD) and normal thyroid volume; 4) 18 adolescents aged 14–17 years with SDD and DNG. Results. The highest values of Zn were determined during the physiological puberty by itself within its physiologic course ((16.52; 14.27–18.66) mmol/l), which is significantly more than in the pre- ((13.53; 12.77–16.41) mmol/l; p
Lane S. Palmer - One of the best experts on this subject based on the ideXlab platform.
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Ovotesticular disorder of Sexual Development (true hermaphroditism).
Urology, 2008Co-Authors: Ann-leslie Berger-zaslav, Lakshmi Mehta, Jessy Jacob, Theresa Mercado, Inder Gadi, James Tepperberg, Lane S. PalmerAbstract:Objectives To determine the mechanism for the 46,XX/46,XY karyotype observed in a patient with an ovotesticular disorder of Sexual Development (ie, true hermaphroditism). Methods Cytogenetic, molecular cytogenetic, and molecular DNA analyses were performed on the blood, skin, and left and right gonadal tissue from 2 surgical procedures. The results of these studies were used to determine whether the ovotesticular disorder of Sexual Development resulted from mosaicism or tetragametic chimerism. Results Cytogenetic and molecular analyses revealed a mixture of 46,XX and 46,XY cells in most tissues. DNA analysis from the gonadal tissues from surgeries 1 and 2 was performed. Highly polymorphic loci from 12 different chromosomes were examined for the presence of ≥1 paternal or maternal alleles. Three loci were highly informative: D14S544 (14q32.2), DS14S583 (14q21.3), and SE33 (6q14). Each demonstrated the presence of 2 paternal and 2 maternal alleles, indicating that the ovotesticular disorder of Sexual Development resulted from tetragametic chimerism. Conclusions Based on the findings of the cytogenetic, molecular cytogenetic, and DNA analyses of the polymorphic markers from several different loci, it was confirmed that the patient had tetragametic chimerism. This case has assisted in increasing our knowledge of the possible mechanisms causing this rare and complex disorder.
