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Sample records for serotype mating type

  1. Diploids in the Cryptococcus neoformans Serotype A Population Homozygous for the α Mating Type Originate via Unisexual Mating

    PubMed Central

    Lin, Xiaorong; Patel, Sweta; Litvintseva, Anastasia P.; Floyd, Anna; Mitchell, Thomas G.; Heitman, Joseph

    2009-01-01

    The ubiquitous environmental human pathogen Cryptococcus neoformans is traditionally considered a haploid fungus with a bipolar mating system. In nature, the α mating type is overwhelmingly predominant over a. How genetic diversity is generated and maintained by this heterothallic fungus in a largely unisexual α population is unclear. Recently it was discovered that C. neoformans can undergo same-sex mating under laboratory conditions generating both diploid intermediates and haploid recombinant progeny. Same-sex mating (α-α) also occurs in nature as evidenced by the existence of natural diploid αADα hybrids that arose by fusion between two α cells of different serotypes (A and D). How significantly this novel sexual style contributes to genetic diversity of the Cryptococcus population was unknown. In this study, ∼500 natural C. neoformans isolates were tested for ploidy and close to 8% were found to be diploid by fluorescence flow cytometry analysis. The majority of these diploids were serotype A isolates with two copies of the α MAT locus allele. Among those, several are intra-varietal allodiploid hybrids produced by fusion of two genetically distinct α cells through same-sex mating. The majority, however, are autodiploids that harbor two seemingly identical copies of the genome and arose via either endoreplication or clonal mating. The diploids identified were isolated from different geographic locations and varied genotypically and phenotypically, indicating independent non-clonal origins. The present study demonstrates that unisexual mating produces diploid isolates of C. neoformans in nature, giving rise to populations of hybrids and mixed ploidy. Our findings underscore the importance of same-sex mating in shaping the current population structure of this important human pathogenic fungus, with implications for mechanisms of selfing and inbreeding in other microbial pathogens. PMID:19180236

  2. Fifty years of research on serotypes and mating types in Dileptus anser: A review.

    PubMed

    Uspenskaya, Zoya I; Yudin, Alexander L

    2016-04-01

    The ciliate Dileptus anser is increasingly used as a laboratory model not only in protozoological research sensu stricto, but also in general biology. However, genetic studies of this ciliate have never been carried out, and this species is new to the comparative genetics of ciliates. This review describes the genetic experiments conducted at the Institute of Cytology of the Russian Academy of Sciences for the last 50 years. Two characters that are classical for the genetics of ciliates, serotypes and mating types were selected for analysis. The results presented do not fit into conventional genetic schemes and may have epigenetic nature. Features of this model that were revealed earlier (the simplest possible system of multiple mating types, full serial dominance of the alleles in the mat locus, the excretion of pheromones, etc.) are promising with regard to interesting comparisons of breeding systems in ciliates. The results obtained in studies of mating pheromones in D. anser have demonstrated that this model is a perspective one for further exploration of intercellular recognition in lower eukaryotes and of other related issues. Copyright © 2015 Elsevier GmbH. All rights reserved.

  3. Cryptococcus neoformans/Cryptococcus gattii species complex in southern Italy: an overview on the environmental diffusion of serotypes, genotypes and mating-types.

    PubMed

    Romeo, Orazio; Scordino, Fabio; Chillemi, Valeria; Criseo, Giuseppe

    2012-10-01

    Given the lack of comprehensive molecular epidemiology studies in Reggio Calabria and Messina, Italy, we decided to perform an extensive environmental sampling to describe the current molecular epidemiology of C. neoformans/C. gattii species complex in southern Italy. In this study, we report the occurrence of serotypes, genotypes and mating-types of isolates of the C. neoformans/C. gattii species complex recovered from environmental sources. In addition, a number of environmental C. neoformans var. grubii strains, isolated in 1997 by our laboratory, were also retrospectively examined in order to compare their genotypes with those recently found and to infer the possible epidemiological changes in our country. One hundred and twenty-two isolates were identified as being C. neoformans, whereas only one was found to belong to C. gattii serotype B, genotype VGI and mating-type alpha. Our data revealed that all environmental isolates of C. neoformans recovered here as well as those previously isolated in 1997 belong to serotype A and genotype VNI and posses a mating-type alpha allele.

  4. Prevalence, serotypes and mating patterns of Cryptococcus neoformans in the pellets of different avifauna in Madras, India.

    PubMed

    Gokulshankar, S; Ranganathan, S; Ranjith, M S; Ranjithsingh, A J A

    2004-08-01

    A total of 887 pellets of different avifauna were screened for the presence of Cryptococcus neoformans. One hundred and six of 887 samples (12%) yielded Cr. neoformans in culture. The report on the isolation of Cr. neoformans from the pellets of the crow appears to be new and of greater significance because of the ubiquitous prevalence of this bird in India. The prevalence of both MAT a and MAT alpha mating types were recorded. The serotype D was predominant over serotype A. The findings of the present study reveal the growing diverse ecological niche of Cr. neoformans in a the pellets of various avifauna in India.

  5. Cryptococcus gattii sero-mating type allelic pattern determined by multiplex PCR.

    PubMed

    Cogliati, M; D'Amicis, R; Tortorano, A M

    2015-02-01

    Molecular methods to differentiate serotypes, mating types and molecular types of Cryptococcus neoformans and C. gattii are important tools to understand epidemiology and pathogenesis of these pathogens. In this study, a multiplex polymerase chain reaction (PCR) approach was applied to sero-mating typing of C. gattii strains. Four pairs of primers were designed to target 4 allele-specific genes located in the mating-type locus. Twenty-three C. gattii strains, presenting different mating types and serotypes, were tested to validate the method. The method was able to identify all sero-mating allelic patterns including hybrid combinations, and therefore, it represents a simple one-step PCR for sero-mating typing of C. gattii strains.

  6. The evolution of mating type switching

    PubMed Central

    Hadjivasiliou, Zena; Pomiankowski, Andrew; Kuijper, Bram

    2016-01-01

    Predictions about the evolution of sex determination mechanisms have mainly focused on animals and plants, whereas unicellular eukaryotes such as fungi and ciliates have received little attention. Many taxa within the latter groups can stochastically switch their mating type identity during vegetative growth. Here, we investigate the hypothesis that mating type switching overcomes distortions in the distribution of mating types due to drift during asexual growth. Using a computational model, we show that smaller population size, longer vegetative periods and more mating types lead to greater distortions in the distribution of mating types. However, the impact of these parameters on optimal switching rates is not straightforward. We find that longer vegetative periods cause reductions and considerable fluctuations in the switching rate over time. Smaller population size increases the strength of selection for switching but has little impact on the switching rate itself. The number of mating types decreases switching rates when gametes can freely sample each other, but increases switching rates when there is selection for speedy mating. We discuss our results in light of empirical work and propose new experiments that could further our understanding of sexuality in isogamous eukaryotes. PMID:27271362

  7. The evolution of mating type switching.

    PubMed

    Hadjivasiliou, Zena; Pomiankowski, Andrew; Kuijper, Bram

    2016-07-01

    Predictions about the evolution of sex determination mechanisms have mainly focused on animals and plants, whereas unicellular eukaryotes such as fungi and ciliates have received little attention. Many taxa within the latter groups can stochastically switch their mating type identity during vegetative growth. Here, we investigate the hypothesis that mating type switching overcomes distortions in the distribution of mating types due to drift during asexual growth. Using a computational model, we show that smaller population size, longer vegetative periods and more mating types lead to greater distortions in the distribution of mating types. However, the impact of these parameters on optimal switching rates is not straightforward. We find that longer vegetative periods cause reductions and considerable fluctuations in the switching rate over time. Smaller population size increases the strength of selection for switching but has little impact on the switching rate itself. The number of mating types decreases switching rates when gametes can freely sample each other, but increases switching rates when there is selection for speedy mating. We discuss our results in light of empirical work and propose new experiments that could further our understanding of sexuality in isogamous eukaryotes. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

  8. Basidiomycete Mating Type Genes and Pheromone Signaling▿

    PubMed Central

    Raudaskoski, Marjatta; Kothe, Erika

    2010-01-01

    The genome sequences of the basidiomycete Agaricomycetes species Coprinopsis cinerea, Laccaria bicolor, Schizophyllum commune, Phanerochaete chrysosporium, and Postia placenta, as well as of Cryptococcus neoformans and Ustilago maydis, are now publicly available. Out of these fungi, C. cinerea, S. commune, and U. maydis, together with the budding yeast Saccharomyces cerevisiae, have been investigated for years genetically and molecularly for signaling in sexual reproduction. The comparison of the structure and organization of mating type genes in fungal genomes reveals an amazing conservation of genes regulating the sexual reproduction throughout the fungal kingdom. In agaricomycetes, two mating type loci, A, coding for homeodomain type transcription factors, and B, encoding a pheromone/receptor system, regulate the four typical mating interactions of tetrapolar species. Evidence for both A and B mating type genes can also be identified in basidiomycetes with bipolar systems, where only two mating interactions are seen. In some of these fungi, the B locus has lost its self/nonself discrimination ability and thus its specificity while retaining the other regulatory functions in development. In silico analyses now also permit the identification of putative components of the pheromone-dependent signaling pathways. Induction of these signaling cascades leads to development of dikaryotic mycelia, fruiting body formation, and meiotic spore production. In pheromone-dependent signaling, the role of heterotrimeric G proteins, components of a mitogen-activated protein kinase (MAPK) cascade, and cyclic AMP-dependent pathways can now be defined. Additionally, the pheromone-dependent signaling through monomeric, small GTPases potentially involved in creating the polarized cytoskeleton for reciprocal nuclear exchange and migration during mating is predicted. PMID:20190072

  9. Molecular epidemiology of clinical and environmental isolates of the Cryptococcus neoformans species complex reveals a high genetic diversity and the presence of the molecular type VGII mating type a in Colombia.

    PubMed

    Escandón, Patricia; Sánchez, Adriana; Martínez, Marcela; Meyer, Wieland; Castañeda, Elizabeth

    2006-06-01

    The aim of this study was to investigate the epidemiological relationships of clinical and environmental isolates of the Cryptococcus neoformans species complex in Colombia. The current study reflects data from 1987 to 2004. In Colombia serotypes A and B are most frequently recovered from patients and the environment. Of the 178 clinical isolates studied, 91.1% were of serotype A, 8.4% serotype B and 0.5% serotype C. Of the 247 environmental isolates, 44.2% were of serotype A, 42.6% serotype B and 13.2% serotype C. No serotype D isolates were isolated. Serotype AD has not been recovered in Colombia. PCR fingerprinting with the primers M13, (GACA)4 and (GTG)5 and URA5 gene restriction fragment length polymorphism analysis grouped the majority of clinical serotype A and environmental serotype B isolates into the molecular types VNI (98.1%) and VGII (100%), respectively. Mating type alpha was determined in 99.3% of serotype A isolates, but 96.6% of serotype B isolates were of mating type a. Similar profiles between clinical and environmental isolates suggest that the patients may have acquired the infection from the environment. The data presented form part of the Colombian contribution to the ongoing global survey of the C. neoformans species complex.

  10. Inversion of the Chromosomal Region between Two Mating Type Loci Switches the Mating Type in Hansenula polymorpha

    PubMed Central

    Maekawa, Hiromi; Kaneko, Yoshinobu

    2014-01-01

    Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent mating type cassettes, in addition to an active MAT locus, are essential components of the mating type switching mechanism. In this study, we investigated the structure and functions of mating type genes in H. polymorpha (also designated as Ogataea polymorpha). The H. polymorpha genome was found to harbor two MAT loci, MAT1 and MAT2, that are ∼18 kb apart on the same chromosome. MAT1-encoded α1 specifies α cell identity, whereas none of the mating type genes were required for a identity and mating. MAT1-encoded α2 and MAT2-encoded a1 were, however, essential for meiosis. When present in the location next to SLA2 and SUI1 genes, MAT1 or MAT2 was transcriptionally active, while the other was repressed. An inversion of the MAT intervening region was induced by nutrient limitation, resulting in the swapping of the chromosomal locations of two MAT loci, and hence switching of mating type identity. Inversion-deficient mutants exhibited severe defects only in mating with each other, suggesting that this inversion is the mechanism of mating type switching and homothallism. This chromosomal inversion-based mechanism represents a novel form of mating type switching that requires only two MAT loci. PMID:25412462

  11. Inversion of the chromosomal region between two mating type loci switches the mating type in Hansenula polymorpha.

    PubMed

    Maekawa, Hiromi; Kaneko, Yoshinobu

    2014-11-01

    Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent mating type cassettes, in addition to an active MAT locus, are essential components of the mating type switching mechanism. In this study, we investigated the structure and functions of mating type genes in H. polymorpha (also designated as Ogataea polymorpha). The H. polymorpha genome was found to harbor two MAT loci, MAT1 and MAT2, that are ∼18 kb apart on the same chromosome. MAT1-encoded α1 specifies α cell identity, whereas none of the mating type genes were required for a identity and mating. MAT1-encoded α2 and MAT2-encoded a1 were, however, essential for meiosis. When present in the location next to SLA2 and SUI1 genes, MAT1 or MAT2 was transcriptionally active, while the other was repressed. An inversion of the MAT intervening region was induced by nutrient limitation, resulting in the swapping of the chromosomal locations of two MAT loci, and hence switching of mating type identity. Inversion-deficient mutants exhibited severe defects only in mating with each other, suggesting that this inversion is the mechanism of mating type switching and homothallism. This chromosomal inversion-based mechanism represents a novel form of mating type switching that requires only two MAT loci.

  12. Odd mating-type substances may work as precursor molecules of even mating-type substances in Paramecium caudatum.

    PubMed

    Xu, X; Kumakura, M; Kaku, E; Takahashi, M

    2001-01-01

    Mating-type substances are key molecules in the sexual recognition of the odd (O) and even (E) complementary mating-type cells in Paramecium caudatum. Indirect evidence suggested that the substances were proteins and were located on ventral surface cilia. Monoclonal antibodies inhibiting the mating reactivity of the O cells have been obtained. Using these antibodies, we tried to detect antigen molecules as dot-blot signals. Strong dot-blot signals of antigens were only detected from the mating reactive cells, but they were not detected from the well-fed and starved cells without mating reactivity. In addition to identifying the antigen on cilia and cytoplasm of the O cell, the antigen was detected from the cytoplasm of the E cells but never from their cilia. Furthermore, extracts of the E cells induced mating reaction with the living E cells but not with O cells. Thus, the O mating-type substances exist in the cytoplasm of the E mating-type cells, supporting strongly the hypothesis that O mating-type substances are precursor molecules of the E mating-type substances.

  13. Mating types and sexual development in filamentous ascomycetes.

    PubMed Central

    Coppin, E; Debuchy, R; Arnaise, S; Picard, M

    1997-01-01

    The progress made in the molecular characterization of the mating types in several filamentous ascomycetes has allowed us to better understand their role in sexual development and has brought to light interesting biological problems. The mating types of Neurospora crassa, Podospora anserina, and Cochliobolus heterostrophus consist of unrelated and unique sequences containing one or several genes with multiple functions, related to sexuality or not, such as vegetative incompatibility in N. crassa. The presence of putative DNA binding domains in the proteins encoded by the mating-type (mat) genes suggests that they may be transcriptional factors. The mat genes play a role in cell-cell recognition at fertilization, probably by activating the genes responsible for the hormonal signal whose occurrence was previously demonstrated by physiological experiments. They also control recognition between nuclei at a later stage, when reproductive nuclei of each mating type which have divided in the common cytoplasm pair within the ascogenous hyphae. How self is distinguished from nonself at the nuclear level is not known. The finding that homothallic species, able to mate in the absence of a partner, contain both mating types in the same haploid genome has raised more issues than it has resolved. The instability of the mating type, in particular in Sclerotinia trifolorium and Botrytinia fuckeliana, is also unexplained. This diversity of mating systems, still more apparent if the yeasts and the basidiomycetes are taken into account, clearly shows that no single species can serve as a universal mating-type model. PMID:9409146

  14. What uses are mating types? The "developmental switch" model.

    PubMed

    Perrin, Nicolas

    2012-04-01

    Why mating types exist at all is subject to much debate. Among hypotheses, mating types evolved to control organelle transmission during sexual reproduction, or to prevent inbreeding or same-clone mating. Here I review data from a diversity of taxa (including ciliates, algae, slime molds, ascomycetes, and basidiomycetes) to show that the structure and function of mating types run counter the above hypotheses. I argue instead for a key role in triggering developmental switches. Genomes must fulfill a diversity of alternative programs along the sexual cycle. As a haploid gametophyte, an individual may grow vegetatively (through haploid mitoses), or initiate gametogenesis and mating. As a diploid sporophyte, similarly, it may grow vegetatively (through diploid mitoses) or initiate meiosis and sporulation. Only diploid sporophytes (and not haploid gametophytes) should switch on the meiotic program. Similarly, only haploid gametophytes (not sporophytes) should switch on gametogenesis and mating. And they should only do so when other gametophytes are ready to do the same in the neighborhood. As argued here, mating types have evolved primarily to switch on the right program at the right moment.

  15. Test of a novel Streptococcus pneumoniae serotype 6C type specific polyclonal antiserum (factor antiserum 6d) and characterisation of serotype 6C isolates in Denmark.

    PubMed

    Lambertsen, Lotte; Kerrn, Mette B

    2010-09-24

    In 2007, Park et al. identified a novel serotype among Streptococcus pneumoniae serogroup 6 which they named serotype 6C. The aim of this study was to evaluate with the Neufeld test a novel S. pneumoniae serotype 6C type specific polyclonal antiserum. In addition, serotype 6C isolates found in Denmark in 2007 and 2008 as well as eight old original serotype 6A isolates were characterised. In this study, 181 clinical Streptococcus pneumoniae isolates from Denmark 2007 and 2008 were examined; 96 isolates had previously been typed as serotype 6A and 85 as serotype 6B. In addition, eight older isolates from 1952 to 1987, earlier serotyped as 6A, were examined. Serotype 6C isolates were identified by PCR and serotyping with the Neufeld test using the novel type specific polyclonal antiserum, factor antiserum 6 d, in addition to factor antisera 6b, 6b* (absorbed free for cross-reactions to serotype 6C) and 6c. All antisera are commercially available and antiserum 6b obtained from the supplier after 1 January 2009 is antiserum 6b*. All serotype 6C isolates were further characterised using multi-locus sequence typing. When retesting all 96 original serotype 6A isolates by PCR and the Neufeld test, 29.6% (24 of 81) of the invasive isolates in Denmark from 2007 and 2008 were recognised as serotype 6C. In addition, three of eight old isolates originally serotyped as 6A were identified to be serotype 6C. The oldest serotype 6C isolate was from 1962. The serotype 6C isolates belonged to eleven different sequence types (ST) and nine clonal complexes (CC), ST1692 (CC395), ST386 (CC386) and ST481 (CC460) were the predominant types. We tested a novel polyclonal antiserum 6 d, as well as modified antiserum 6b*, provided a scheme for the serotyping of S. pneumoniae serogroup 6 using the Neufeld test and compared the serotyping method with PCR based methods. The two types of methods provided the same results. In future, it will, therefore, be possible to test also serotype 6C in

  16. An Evolutionary Perspective on Yeast Mating-Type Switching.

    PubMed

    Hanson, Sara J; Wolfe, Kenneth H

    2017-05-01

    Cell differentiation in yeast species is controlled by a reversible, programmed DNA-rearrangement process called mating-type switching. Switching is achieved by two functionally similar but structurally distinct processes in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe In both species, haploid cells possess one active and two silent copies of the mating-type locus (a three-cassette structure), the active locus is cleaved, and synthesis-dependent strand annealing is used to replace it with a copy of a silent locus encoding the opposite mating-type information. Each species has its own set of components responsible for regulating these processes. In this review, we summarize knowledge about the function and evolution of mating-type switching components in these species, including mechanisms of heterochromatin formation, MAT locus cleavage, donor bias, lineage tracking, and environmental regulation of switching. We compare switching in these well-studied species to others such as Kluyveromyces lactis and the methylotrophic yeasts Ogataea polymorpha and Komagataella phaffii We focus on some key questions: Which cells switch mating type? What molecular apparatus is required for switching? Where did it come from? And what is the evolutionary purpose of switching? Copyright © 2017 by the Genetics Society of America.

  17. An Evolutionary Perspective on Yeast Mating-Type Switching

    PubMed Central

    Hanson, Sara J.; Wolfe, Kenneth H.

    2017-01-01

    Cell differentiation in yeast species is controlled by a reversible, programmed DNA-rearrangement process called mating-type switching. Switching is achieved by two functionally similar but structurally distinct processes in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. In both species, haploid cells possess one active and two silent copies of the mating-type locus (a three-cassette structure), the active locus is cleaved, and synthesis-dependent strand annealing is used to replace it with a copy of a silent locus encoding the opposite mating-type information. Each species has its own set of components responsible for regulating these processes. In this review, we summarize knowledge about the function and evolution of mating-type switching components in these species, including mechanisms of heterochromatin formation, MAT locus cleavage, donor bias, lineage tracking, and environmental regulation of switching. We compare switching in these well-studied species to others such as Kluyveromyces lactis and the methylotrophic yeasts Ogataea polymorpha and Komagataella phaffii. We focus on some key questions: Which cells switch mating type? What molecular apparatus is required for switching? Where did it come from? And what is the evolutionary purpose of switching? PMID:28476860

  18. White-opaque Switching in Different Mating Type-like Locus Gene Types of Clinical Candida albicans Isolates.

    PubMed

    Li, Hou-Min; Shimizu-Imanishi, Yumi; Tanaka, Reiko; Li, Ruo-Yu; Yaguchi, Takashi

    2016-11-20

    Candida albicans (C. albicans) can become a pathogen causing superficial as well as life-threatening systemic infections, especially in immunocompromised patients. Many phenotypic attributes contribute to its capacity to colonize human organs. In our study, 93 C. albicans isolates from patients of various candidiasis in a hospital of China were surveyed. We aimed to investigate the white-opaque (WO) switching competence, drug sensitivity, and virulence of mating type-like (MTL) a/α isolates. Internal transcribed spacer (ITS) gene and the MTL configuration were detected in all the isolates by reverse transcription-polymerase chain reaction. White/opaque phenotype and doubling time of cell growth were determined. The minimum inhibitory concentrations of antifungal agent were measured using broth microdilution method. Sixty-four isolates (69.6%) were classified to serotype A, 19 (20.6%) to serotype B, and 9 (9.8%) to serotype C. Moreover, phylogenetic analysis showed that these isolates were divided into four different subgroups of ITS genotypes. Most of our clinical isolates were MTL a/α type, while 6.8% remained MTL a or MTLα type. The frequency of opaque phenotype was 71.0% (66 isolates). Following the guidelines of Clinical and Laboratory Standards Institute M27-A3, all isolates were susceptible to caspofungin and a few (0.6-3.2%) of them showed resistance against amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole. From these analyses, there were comparatively more C. albicans strains classified into serotype B, and the frequency of opaque phase strains was significant in the clinical isolates from China. Genetic, phenotypic, or drug susceptibility patterns were not significantly different from previous studies. MTL a/α isolates could also undergo WO switching which facilitates their survival.

  19. White-opaque Switching in Different Mating Type-like Locus Gene Types of Clinical Candida albicans Isolates

    PubMed Central

    Li, Hou-Min; Shimizu-Imanishi, Yumi; Tanaka, Reiko; Li, Ruo-Yu; Yaguchi, Takashi

    2016-01-01

    Background: Candida albicans (C. albicans) can become a pathogen causing superficial as well as life-threatening systemic infections, especially in immunocompromised patients. Many phenotypic attributes contribute to its capacity to colonize human organs. In our study, 93 C. albicans isolates from patients of various candidiasis in a hospital of China were surveyed. We aimed to investigate the white-opaque (WO) switching competence, drug sensitivity, and virulence of mating type-like (MTL) a/α isolates. Methods: Internal transcribed spacer (ITS) gene and the MTL configuration were detected in all the isolates by reverse transcription-polymerase chain reaction. White/opaque phenotype and doubling time of cell growth were determined. The minimum inhibitory concentrations of antifungal agent were measured using broth microdilution method. Results: Sixty-four isolates (69.6%) were classified to serotype A, 19 (20.6%) to serotype B, and 9 (9.8%) to serotype C. Moreover, phylogenetic analysis showed that these isolates were divided into four different subgroups of ITS genotypes. Most of our clinical isolates were MTLa/α type, while 6.8% remained MTLa or MTLα type. The frequency of opaque phenotype was 71.0% (66 isolates). Following the guidelines of Clinical and Laboratory Standards Institute M27-A3, all isolates were susceptible to caspofungin and a few (0.6–3.2%) of them showed resistance against amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole. Conclusions: From these analyses, there were comparatively more C. albicans strains classified into serotype B, and the frequency of opaque phase strains was significant in the clinical isolates from China. Genetic, phenotypic, or drug susceptibility patterns were not significantly different from previous studies. MTLa/α isolates could also undergo WO switching which facilitates their survival. PMID:27824006

  20. Structures of the Mating-Type Loci of Cordyceps takaomontana

    PubMed Central

    Yokoyama, Eiji; Yamagishi, Kenzo; Hara, Akira

    2003-01-01

    Nucleotide sequences of the mating-type loci MAT1-1 and MAT1-2 of Cordyceps takaomontana were determined, which is the first such report for the clavicipitaceous fungi. MAT1-1 contains two mating-type genes, MAT1-1-1 and MAT1-1-2, but MAT1-1-3 could not be found. On the other hand, MAT1-2 has MAT1-2-1. A pseudogene of MAT1-1-1 is located next to MAT1-2. PMID:12902305

  1. Mating-type genes and MAT switching in Saccharomyces cerevisiae.

    PubMed

    Haber, James E

    2012-05-01

    Mating type in Saccharomyces cerevisiae is determined by two nonhomologous alleles, MATa and MATα. These sequences encode regulators of the two different haploid mating types and of the diploids formed by their conjugation. Analysis of the MATa1, MATα1, and MATα2 alleles provided one of the earliest models of cell-type specification by transcriptional activators and repressors. Remarkably, homothallic yeast cells can switch their mating type as often as every generation by a highly choreographed, site-specific homologous recombination event that replaces one MAT allele with different DNA sequences encoding the opposite MAT allele. This replacement process involves the participation of two intact but unexpressed copies of mating-type information at the heterochromatic loci, HMLα and HMRa, which are located at opposite ends of the same chromosome-encoding MAT. The study of MAT switching has yielded important insights into the control of cell lineage, the silencing of gene expression, the formation of heterochromatin, and the regulation of accessibility of the donor sequences. Real-time analysis of MAT switching has provided the most detailed description of the molecular events that occur during the homologous recombinational repair of a programmed double-strand chromosome break.

  2. Mating-Type Genes and MAT Switching in Saccharomyces cerevisiae

    PubMed Central

    Haber, James E.

    2012-01-01

    Mating type in Saccharomyces cerevisiae is determined by two nonhomologous alleles, MATa and MATα. These sequences encode regulators of the two different haploid mating types and of the diploids formed by their conjugation. Analysis of the MATa1, MATα1, and MATα2 alleles provided one of the earliest models of cell-type specification by transcriptional activators and repressors. Remarkably, homothallic yeast cells can switch their mating type as often as every generation by a highly choreographed, site-specific homologous recombination event that replaces one MAT allele with different DNA sequences encoding the opposite MAT allele. This replacement process involves the participation of two intact but unexpressed copies of mating-type information at the heterochromatic loci, HMLα and HMRa, which are located at opposite ends of the same chromosome-encoding MAT. The study of MAT switching has yielded important insights into the control of cell lineage, the silencing of gene expression, the formation of heterochromatin, and the regulation of accessibility of the donor sequences. Real-time analysis of MAT switching has provided the most detailed description of the molecular events that occur during the homologous recombinational repair of a programmed double-strand chromosome break. PMID:22555442

  3. The mating type-like loci of Candida glabrata.

    PubMed

    Yáñez-Carrillo, Patricia; Robledo-Márquez, Karina A; Ramírez-Zavaleta, Candy Y; De Las Peñas, Alejandro; Castaño, Irene

    2014-01-01

    Candida glabrata, a haploid and opportunistic fungal pathogen that has not known sexual cycle, has conserved the majority of the genes required for mating and cell type identity. The C. glabrata genome contains three mating-type-like loci called MTL1, MTL2 and MTL3. The three loci encode putative transcription factors, a1, α1 and α2 that regulate cell type identity and sexual reproduction in other fungi like the closely related Saccharomyces cerevisiae. MTL1 can contain either a or α information. MTL2, which contains a information and MTL3 with α information, are relatively close to two telomeres. MTL1 and MTL2 are transcriptionally active, while MTL3 is subject to an incomplete silencing nucleated at the telomere that depends on the silencing proteins Sir2, Sir3, Sir4, yKu70/80, Rif1, Rap1 and Sum1. C. glabrata does not seem to maintain cell type identity, as cell type-specific genes are expressed regardless of the type (or even absence) of mating information. These data highlight important differences in the control of mating and cell type identity between the non-pathogenic yeast S. cerevisiae and C. glabrata, which might explain the absence of a sexual cycle in C. glabrata. The fact that C. glabrata has conserved the vast majority of the genes involved in mating might suggest that some of these genes perhaps have been rewired to control other processes important for the survival inside the host as a commensal or as a human pathogen. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  4. Mating-type locus characterization and variation in Pyrenophora semeniperda

    Treesearch

    Julie Leanna Henry

    2015-01-01

    Pyrenophora semeniperda is a generalist fungal pathogen that occurs primarily on monocot seed hosts. It is in the phylum Ascomycota, which includes both self-compatible (homothallic) and self-incompatible (heterothallic) species. Homothallic fungal species contain complementary mating-type (MAT) idiomorphs in a single unikaryotic strain, while heterothallic strains...

  5. Sequence diversity of mating-type genes in Phaeosphaeria avenaria.

    PubMed

    Ueng, Peter P; Dai, Qun; Cui, Kai-rong; Czembor, Paweł C; Cunfer, Barry M; Tsang, H; Arseniuk, Edward; Bergstrom, Gary C

    2003-05-01

    Phaeosphaeria avenaria, one of the causal agents of stagonospora leaf blotch diseases in cereals, is composed of two subspecies, P. avenaria f. sp. triticea (Pat) and P. avenaria f. sp. avenaria (Paa). The Pat subspecies was grouped into Pat1-Pat3, based on restriction fragment length polymorphism (RFLP) and ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequences in previous studies. Mating-type genes and their potential use in phylogeny and molecular classification were studied by DNA hybridization and PCR amplification. The majority of Pat1 isolates reported to be homothallic and producing sexual reproduction structures on cultural media had only the MAT1-1 gene. Minor sequence variations were found in the conserved region of MAT1-1 gene in Pat1 isolates. However, both mating-type genes, MAT1-1 and MAT1-2, were identified in P. avenaria isolates represented by ATCC12277 from oats (Paa) and the Pat2 isolates from foxtail barley ( Hordeum jubatum L.). Cluster analyses based on mating-type gene conserved regions revealed that cereal Phaeosphaeria is not phylogenetically closely related to other ascomycetes, including Mycosphaerella graminicola (anamorph Septoria tritici). The sequence diversity of mating-type genes in Pat and Paa supports our previous phylogenetic relationship and molecular classification based on RFLP fingerprinting and rDNA ITS sequences.

  6. Development of a cps-based multiplex PCR for typing of Actinobacillus pleuropneumoniae serotypes 1, 2 and 5.

    PubMed

    Ito, Hiroya

    2010-05-01

    A cps-based multiplex PCR for typing of Actinobacillus pleuropneumoniae serotypes 1, 2 and 5 was developed. This method should be specific and practical in Japan where more than 88% of isolates are serotypes 1, 2 or 5.

  7. The influence of the mating type on virulence of Mucor irregularis.

    PubMed

    Xu, Wenqi; Liang, Guanzhao; Peng, Jingwen; Long, Zhimin; Li, Dongmei; Fu, Meihua; Wang, Qiong; Shen, Yongnian; Lv, Guixia; Mei, Huan; Tsui, Clement K M; Liu, Weida

    2017-09-06

    Mucor irregularis is an emerging fungal pathogen that cause cutaneous infection and could cause death. However, little is known about its mechanism of pathogenesis. There is evidence suggesting virulence vary with mating types in fungi, including the Mucorales. Here, we characterized the mating type locus of M. irregularis and the mating type ratio of 17 clinical isolates in China. Genomic data indicated M. irregularis is heterothallic having two mating types - bearing either SexP or SexM allele. Also, we employed a mice model to study the inflammation and pathological effects of different mating types. The comparison of the inflammatory response, cytokine profiles and Th-1, Th-2 and Th-17 cells numbers in each mating type treated mice showed that the severity and disease progress were enhanced in (+) mating type treated mice. One (+/0) mutant strain, with multiple mutations at the mating locus, had defects in sexual mating ability but appeared to be more virulent than the (-) mating type. Although (+) mating type appeared to be more virulent, most of our clinical isolates presented belonged to (-) mating type. Our findings support the involvement of MAT genes in sexual fertility, and the influence of mating type on the severity of cutaneous infection.

  8. Mating types in Paramecium and a molecular approach to their determination.

    PubMed

    Sawka, Natalia

    2012-01-01

    Mating types are expressed in ciliates for the duration of the mature period of their clonal cycle. During cell conjugation the reciprocal fertilization of complementary mating types takes place. Models of mating type determination in the Paramecium aurelia species complex based on classical genetics are reviewed including molecular aspects of the studies.

  9. Mating-type Gene Switching in Saccharomyces cerevisiae.

    PubMed

    Lee, Cheng-Sheng; Haber, James E

    2015-04-01

    The budding yeast Saccharomyces cerevisiae has two alternative mating types designated MATa and MATα. These are distinguished by about 700 bp of unique sequences, Ya or Yα, including divergent promoter sequences and part of the open reading frames of genes that regulate mating phenotype. Homothallic budding yeast, carrying an active HO endonuclease gene, HO, can switch mating type through a recombination process known as gene conversion, in which a site-specific double-strand break (DSB) created immediately adjacent to the Y region results in replacement of the Y sequences with a copy of the opposite mating type information, which is harbored in one of two heterochromatic donor loci, HMLα or HMRa. HO gene expression is tightly regulated to ensure that only half of the cells in a lineage switch to the opposite MAT allele, thus promoting conjugation and diploid formation. Study of the silencing of these loci has provided a great deal of information about the role of the Sir2 histone deacetylase and its associated Sir3 and Sir4 proteins in creating heterochromatic regions. MAT switching has been examined in great detail to learn about the steps in homologous recombination. MAT switching is remarkably directional, with MATa recombining preferentially with HMLα and MATα using HMRa. Donor preference is controlled by a cis-acting recombination enhancer located near HML. RE is turned off in MATα cells but in MATa binds multiple copies of the Fkh1 transcription factor whose forkhead-associated phosphothreonine binding domain localizes at the DSB, bringing HML into conjunction with MATa.

  10. Gamete signalling underlies the evolution of mating types and their number

    PubMed Central

    Hadjivasiliou, Zena; Pomiankowski, Andrew

    2016-01-01

    The gametes of unicellular eukaryotes are morphologically identical, but are nonetheless divided into distinct mating types. The number of mating types varies enormously and can reach several thousand, yet most species have only two. Why do morphologically identical gametes need to be differentiated into self-incompatible mating types, and why is two the most common number of mating types? In this work, we explore a neglected hypothesis that there is a need for asymmetric signalling interactions between mating partners. Our review shows that isogamous gametes always interact asymmetrically throughout sex and argue that this asymmetry is favoured because it enhances the efficiency of the mating process. We further develop a simple mathematical model that allows us to study the evolution of the number of mating types based on the strength of signalling interactions between gametes. Novel mating types have an advantage as they are compatible with all others and rarely meet their own type. But if existing mating types coevolve to have strong mutual interactions, this restricts the spread of novel types. Similarly, coevolution is likely to drive out less attractive mating types. These countervailing forces specify the number of mating types that are evolutionarily stable. This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’. PMID:27619695

  11. Heterothallic Type of Mating System for Cordyceps cardinalis

    PubMed Central

    Sung, Gi-Ho; Shrestha, Bhushan; Han, Sang-Kuk; Kim, Soo-Young

    2010-01-01

    Cordyceps cardinalis successfully produced its fruiting bodies from multi-ascospore isolates. However, subcultures of multi-ascospore isolates could not produce fruiting bodies after few generations. Fruiting body production also differed from sector to sector of the same isolate. Single ascospore isolates were then co-inoculated in combinations of two to observe the fruiting characteristics. Combinations of certain isolates produced perithecial stromata formation, whereas other combinations did not produce any fruiting bodies. These results show that C. cardinalis is a heterothallic fungus, requiring two isolates of opposite mating types for fruiting body production. It was also shown that single ascospore isolates are hermaphrodites. PMID:23956667

  12. Diphthericin types, bacteriophage types and serotypes of Corynebacterium diphtheriae strains isolated in Australia

    PubMed Central

    Gibson, L. F.; Colman, G.

    1973-01-01

    A dipthericin typing scheme has been constructed using 441 strains of Corynebacterium diptheriae isolated in eastern Australia from 1962 to 1971. Ten types have been distinguished using seven strains of C. diphtheriae and two strains of C. belfanti as indicators of the diphthericins produced by the newly isolated strains. Strains grouped into types L2, L3 and L3a were found only in Melbourne and types L1 and L4 were predominant in Sydney. Type L5 strains were isolated intermittently throughout the period of study and were found in all eastern states. Numerical analysis of the characteristics of the strains suggests that associations exist between, on the one hand, diphthericin type and, on the other hand, bacteriophage type, serotype and biochemical activity. PMID:4203597

  13. Erysipelothrix rhusiopathiae: association of Spa-type with serotype and role in protective immunity.

    PubMed

    Ingebritson, Alaina L; Roth, James A; Hauer, Paul J

    2010-03-16

    A collection of swine, fish, and cetacean Erysipelothrix rhusiopathiae strains representing 16 serotypes was analyzed for possession of the three currently recognized surface protective antigen (spa)-types: spaA, spaB, and spaC. Polymerase chain reaction (PCR) assays and Western blotting with a SpaA-specific monoclonal antibody demonstrated that spa-type is not confined to specific serotype groups. In particular, the spa-type of strains of aquatic origin was more variable than those of terrestrial origin, and possessed the distinct ability to express more than one spa. In a cross-protection study, mice immunized with an E. rhusiopathiae serotype 2 SpaA-type strain and challenged with various E. rhusiopathiae isolates were completely protected against strains exhibiting a single homologous spa, but variably protected against strains possessing a heterologous spa or those harboring more than one spa-type.

  14. Biotyping, serotyping and phage typing of Streptococcus faecalis isolated from dental plaque in the human mouth.

    PubMed

    Smyth, C J; Matthews, H; Halpenny, M K; Brandis, H; Colman, G

    1987-02-01

    Thirty Streptococcus faecalis isolates from mixed dental plaque samples were classified into four groups on the basis of biotype, tetracycline susceptibility, phage type and serotype combinations. The organisms were from patients on haemodialysis, from staff of the dialysis unit, and from controls. Three biotypes were distinguished by seven biochemical tests: production of acid from inositol, sucrose and xylose; rapid or delayed production of acid from sorbitol; gelatin liquefaction; and production of alkaline phosphatase and beta-galactosidase. With a set of eight typing antisera for S. faecalis, 15 strains were non-typable, 12 were serotype 1 and three were serotype 19. With a set of 17 bacteriophages specific for S. faecalis, all of the oral isolates were typable; 40% were lysotype I1 and the remainder lysotype V6b. On the basis of biotype-serotype-phage-type combinations, indications of possible spread of strains between haemodialysis patients and dialysis unit staff were obtained. Biotyping and serotyping of 13 German isolates of S. faecalis of phage type I1 from four clinical sources and tripartite typing of three control strains provided additional evidence for the potential of biotyping in distinguishing between strains of identical serotype and phage type. One oral isolate of S. faecium was of phage type XX. None of the oral isolates of S. faecalis, of which 14 exhibited delayed sorbitol fermentation, reacted with group-G streptococcal grouping reagents or antiserum. Slow sorbitol fermentation does not appear to be a definitive phenotypic marker for S. faecalis strains possessing antigens that react with both group-D and group-G grouping reagents.

  15. Rearrangements of the transposable mating-type cassettes of fission yeast.

    PubMed

    Beach, D H; Klar, A J

    1984-03-01

    The fission yeast, Schizosaccharomyces pombe, switches mating type every few cell divisions. Switching is controlled by the genes of the mating-type locus, which consists of three components, mat1, mat2-P and mat3-M, each separated by approximately 15 kb. Copy transposition of P (Plus) or M (Minus) information from mat2-P or mat3-M into the expression locus mat1 mediates cell type switching. The mating-type locus undergoes events at high frequency (10(-2)-10(-6)) which stabilize one or other mating type. These events are shown to be rearrangements which result in either deletion or insertion of DNA between cassettes.

  16. Serotype IV Sequence Type 468 Group B Streptococcus Neonatal Invasive Disease, Minnesota, USA

    PubMed Central

    Teatero, Sarah; Ferrieri, Patricia

    2016-01-01

    To further understand the emergence of serotype IV group B Streptococcus (GBS) invasive disease, we used whole-genome sequencing to characterize 3 sequence type 468 strains isolated from neonates in Minnesota, USA. We found that strains of tetracycline-resistant sequence type 468 GBS have acquired virulence genes from a putative clonal complex 17 GBS donor by recombination. PMID:27767922

  17. Clonality and serotypes of Streptococcus mutans among children by multilocus sequence typing

    PubMed Central

    Momeni, Stephanie S.; Whiddon, Jennifer; Cheon, Kyounga; Moser, Stephen A.; Childers, Noel K.

    2015-01-01

    Studies using multilocus sequence typing (MLST) have demonstrated that Streptococcus mutans isolates are genetically diverse. Our laboratory previously demonstrated clonality of S. mutans using MLST but could not discount the possibility of sampling bias. In this study, the clonality of randomly selected S. mutans plaque isolates from African American children was examined using MLST. Serotype and presence of collagen-binding proteins (CBP) cnm/cbm were also assessed. One hundred S. mutans isolates were randomly selected for MLST analysis. Sequence analysis was performed and phylogenetic trees were generated using START2 and MEGA. Thirty-four sequence types (ST) were identified of which 27 were unique to this population. Seventy-five percent of the isolates clustered into 16 clonal groups. Serotypes observed were c (n=84), e (n=3), and k (n=11). The prevalence of S. mutans isolates serotype k was notably high at 17.5%. All isolates were cnm/cbm negative. The clonality of S. mutans demonstrated in this study illustrates the importance of localized populations studies and are consistent with transmission. The prevalence of serotype k, a recently proposed systemic pathogen, observed in this study is higher than reported in most populations and is the first report of S. mutans serotype k in a US population. PMID:26443288

  18. Population Structure and Antimicrobial Resistance Profiles of Streptococcus suis Serotype 2 Sequence Type 25 Strains

    PubMed Central

    Athey, Taryn B. T.; Teatero, Sarah; Takamatsu, Daisuke; Wasserscheid, Jessica; Dewar, Ken; Gottschalk, Marcelo; Fittipaldi, Nahuel

    2016-01-01

    Strains of serotype 2 Streptococcus suis are responsible for swine and human infections. Different serotype 2 genetic backgrounds have been defined using multilocus sequence typing (MLST). However, little is known about the genetic diversity within each MLST sequence type (ST). Here, we used whole-genome sequencing to test the hypothesis that S. suis serotype 2 strains of the ST25 lineage are genetically heterogeneous. We evaluated 51 serotype 2 ST25 S. suis strains isolated from diseased pigs and humans in Canada, the United States of America, and Thailand. Whole-genome sequencing revealed numerous large-scale rearrangements in the ST25 genome, compared to the genomes of ST1 and ST28 S. suis strains, which result, among other changes, in disruption of a pilus island locus. We report that recombination and lateral gene transfer contribute to ST25 genetic diversity. Phylogenetic analysis identified two main and distinct Thai and North American clades grouping most strains investigated. These clades also possessed distinct patterns of antimicrobial resistance genes, which correlated with acquisition of different integrative and conjugative elements (ICEs). Some of these ICEs were found to be integrated at a recombination hot spot, previously identified as the site of integration of the 89K pathogenicity island in serotype 2 ST7 S. suis strains. Our results highlight the limitations of MLST for phylogenetic analysis of S. suis, and the importance of lateral gene transfer and recombination as drivers of diversity in this swine pathogen and zoonotic agent. PMID:26954687

  19. Molecular typing of Cryptococcus neoformans by PCR fingerprinting, in comparison with serotyping and Fourier transform infrared-spectroscopy-based phenotyping.

    PubMed

    Lemmer, K; Naumann, D; Raddatz, B; Tintelnot, K

    2004-04-01

    Molecular typing by PCR fingerprinting using the single primer (GACA)4 was performed with 110 isolates of Cryptococcus neoformans. Seventy clinical isolates of C. neoformans var. neoformans from Germany (n = 52) and Africa (n = 18) were included. Of these, serotype A (C. neoformans var. grubii) accounted for 47 isolates, serotype D for 12 and serotype AD for 11. Fourier transform infrared (FT-IR) spectroscopy was evaluated for its discriminatory power in phenotyping. Molecular types, defined by different PCR fingerprinting patterns, were compared to serotypes, and both sets of results were compared with the results of analysis by FT-IR spectroscopy. PCR fingerprinting revealed genotypic diversity within each serotype; it showed three different genotypes (designated VNA1-VNA3) within serotype A, two within serotype D (VND1 and VND2), and three within serotype AD (VNAD1-VNAD3). The nomenclature of molecular types within C. n. var. neoformans, as seen in publications to date, is not uniform. In this study, the name assigned to each genotype was based on the 98.6% concordance of genotypes with serotypes, a correspondence that facilitates interlaboratory comparison. This nomenclature is tentatively recommended as a standard. FT-IR spectroscopy combined with hierarchical cluster analysis successfully distinguished C n. var. neoformans from C. n. var. gattii. For C. n. var. neoformans, FT-IR confirmed three distinct genotypes within serotype A and was able to distinguish isolates derived from particular patients as well as isolates differing at the sub-genotype level. Within C. n. var. gattii, the serotypes B and C did not correlate with the four genotypes VGI-VGIV. However, these serotypes could clearly be separated by FT-IR spectroscopy. The molecular profiles were reproducible, and were more stable and more discriminating than serotyping. In connection with a standardized nomenclature, PCR fingerprinting can be a beneficial tool for global epidemiological studies. FT

  20. Genotype and mating type distribution within clinical Cryptococcus neoformans and Cryptococcus gattii isolates from patients with cryptococcal meningitis in Uberaba, Minas Gerais, Brazil.

    PubMed

    Mora, Delio José; Pedrosa, André Luiz; Rodrigues, Virmondes; Leite Maffei, Claudia Maria; Trilles, Luciana; Dos Santos Lazéra, Márcia; Silva-Vergara, Mario León

    2010-06-01

    We molecularly characterized 81 cryptococcal isolates recovered from cerebrospinal fluid samples of 77 patients diagnosed between 1998 and 2007 as having cryptococcal meningitis in Uberaba Minas Gerais, Brazil. Fifty-seven (74%) were male with a mean age 35.6 years. Seventy-two (88.9%) of the isolates were from 68 AIDS patients and cryp-tococcosis was the first AIDS-defining condition in 38 (55.9%) patients. Cryptococcosis and AIDS were simultaneously diagnosed in 25 (65.8%) of these 38 patients. Genotypes were characterized through the use of URA5 restriction fragment length polymorphisms analysis, the genetic variability was determined using PCR-fingerprinting with the minisatellite-specific primer M13, and the mating type and serotypes were established by PCR. Seventy-six of the 81 isolates were Cryptococcus neoformans (93.8%), while the remaining five were C. gattii (6.1%), but all were mating type alpha. C. neoformans isolates were genotype VNI (serotype A), while C. gattii isolates were VGII. Four of the latter isolates were identical, but only two were from AIDS patients. Six of the nine isolates from non-AIDS patients were VNI. PCR fingerprints of the isolates from two of the three AIDS patients with clinical relapse were 100% identical. The predominance of VNI and mating type alpha is in accordance with data from other parts of the world. The occurrence of VGII in Minas Gerais indicates a geographical expansion within Brazil.

  1. Hypervirulent Clone of Group B Streptococcus Serotype III Sequence Type 283, Hong Kong, 1993–2012

    PubMed Central

    Ang, Irene; Fung, Kitty; Liyanapathirana, Veranja; Luo, Ming Jing; Lai, Raymond

    2016-01-01

    We describe a hypervirulent clone of group B Streptococcus serotype III, subtype 4, sequence type 283, that caused invasive disease with a predilection for meningitis in Hong Kong during 1993–2012. The organism is associated with high mortality and increased summer prevalence and is linked to diseased fish from freshwater fish farms. PMID:27648702

  2. Hypervirulent Clone of Group B Streptococcus Serotype III Sequence Type 283, Hong Kong, 1993-2012.

    PubMed

    Ip, Margaret; Ang, Irene; Fung, Kitty; Liyanapathirana, Veranja; Luo, Ming Jing; Lai, Raymond

    2016-10-01

    We describe a hypervirulent clone of group B Streptococcus serotype III, subtype 4, sequence type 283, that caused invasive disease with a predilection for meningitis in Hong Kong during 1993-2012. The organism is associated with high mortality and increased summer prevalence and is linked to diseased fish from freshwater fish farms.

  3. Group B Streptococcus Serotype III Sequence Type 283 Bacteremia Associated with Consumption of Raw Fish, Singapore

    PubMed Central

    Lin, Yijun; Foo, Kelly; Koh, Han Fang; Tow, Charlene; Zhang, Yiwen; Ang, Li Wei; Cui, Lin; Badaruddin, Hishamuddin; Ooi, Peng Lim; Lin, Raymond Tzer Pin; Cutter, Jeffery

    2016-01-01

    We conducted a retrospective study of 40 case-patients and 58 controls as part of a nationwide investigation of a group B Streptococcus outbreak in Singapore in 2015. Eating a Chinese-style raw fish dish (yusheng) was a major risk factor for bacteremia, particularly caused by serotype III sequence type 283. PMID:27767904

  4. Serotyping of Toxoplasma gondii in Cats (Felis domesticus) Reveals Predominance of Type II Infections in Germany

    USDA-ARS?s Scientific Manuscript database

    Background: Cats are definitive hosts of Toxoplasma gondii and play an essential role in the epidemiology of this parasite. The study aims at clarifying whether cats are able to develop specific antibodies against different clonal types of T. gondii and to determine by serotyping the T. gondii clona...

  5. Genetic and Physical Variability at the Mating Type Locus of the Oomycete, Phytophthora Infestans

    PubMed Central

    Judelson, H. S.

    1996-01-01

    Mating type in the oomyceteous fungus, Phytophthora infestans, is determined by a single locus. In a previous study of a few isolates, the locus segregated in a manner genetically consistent with its linkage to a system of balanced lethal loci. To determine the prevalence of this phenomenon within P. infestans, genetic analyses were performed using isolates representative of the diversity within the species that had been selected by DNA fingerprinting using probes linked to mating type. Non-Mendelian segregation of the mating type locus was observed in crosses performed with each isolate. An unusual group of isolates was identified in which the mating type determinants had been rearranged within the genome; these strains also produced an aberrantly large number of self-fertile progeny. Curiously, in all isolates, markers linked to the mating type locus appeared prone to duplication, transposition, deletion, or other rearrangement. This was not observed for loci unlinked to mating type. Data from the crosses and analyses of marker variation were used to erect models to explain the bases of mating type determination and of the unusual segregation of the chromosomal region containing the mating type locus. PMID:8913745

  6. Mating type gene analysis in apparently asexual Cercospora species is suggestive of cryptic sex.

    PubMed

    Groenewald, Marizeth; Groenewald, Johannes Z; Harrington, Thomas C; Abeln, Edwin C A; Crous, Pedro W

    2006-12-01

    The genus Cercospora consists of numerous important, apparently asexual plant pathogens. We designed degenerate primers from homologous sequences in related species to amplify part of the C. apii, C. apiicola, C. beticola, C. zeae-maydis and C. zeina mating type genes. Chromosome walking was used to determine the full length mating type genes of these species. Primers were developed to amplify and sequence homologous portions of the mating type genes of additional species. Phylogenetic analyses of these sequences revealed little variation among members of the C. apii complex, whereas C. zeae-maydis and C. zeina were found to be dissimilar. The presence of both mating types in approximately even proportions in C. beticola, C. zeae-maydis and C. zeina populations, in contrast to single mating types in C. apii (MAT1) and C. apiicola (MAT2), suggests that a sexual cycle may be active in some of these species.

  7. Development of SCAR markers to determine the mating types of Lepista nuda protoplast monokaryons.

    PubMed

    Li, Dengjin; Liu, Yu; Wang, Peng; Ma, Yuanwei; Wang, Shouxian; Zhao, Shuang; Xu, Feng

    2014-04-01

    Lepista nuda (Bull. ex Fr.) Cooke belongs to Tricholomataceae and is an edible fungus with both economic and medical value. Mycelia were isolated from the fruiting bodies of L. nuda and were used to prepare the protoplast monokaryons. One hundred and fifteen monokaryons were obtained and their mating types were determined using somatic incompatibility tests. Protoplast monokaryons segregated into either the A1B1 or the A2B2 mating types. Inter-simple sequence repeats and sequence-related amplified polymorphism fingerprinting were used to analyse the mating types of these protoplast monokaryons and 16 sequence-characterised amplified region primers were developed to efficiently differentiate between the monokaryon mating types. Multiplex PCR analyses were also established. The data presented here outline a method for the precise and rapid identification of protoplast monokaryon mating types, which has the promise to shorten the period required for conventional crossbreeding.

  8. Impact of serotype and sequence type on the preferential aerosolization of Streptococcus suis.

    PubMed

    Gauthier-Levesque, Léa; Bonifait, Laetitia; Turgeon, Nathalie; Veillette, Marc; Perrott, Phillipa; Grenier, Daniel; Duchaine, Caroline

    2016-05-14

    Streptococcus suis is a swine pathogen that causes pneumonia, septicemia and meningitis. It is also an important zoonotic agent responsible of several outbreaks in China. S. suis strains are classified into 35 serotypes based on the composition of their polysaccharide capsule. S. suis serotype 2 causes the majority of severe infections in pigs and in human, and can be further subdivided into sequence types (STs) based on multilocus sequence typing. The ST1 is associated with highly virulent strains. In North America, the strains most commonly isolated belong to ST25 and ST28, which are respectively moderately and weakly virulent in a mouse model. The presence of S. suis bioaerosols in the air of swine confinement buildings has been previously demonstrated. The aim of this study was to better understand the aerosolization behaviour of S. suis by investigating the preferential aerosolization of various strains of S. suis, belonging to different serotypes or STs, using in-house developed environmental chamber and bubble-burst nebulizer. qPCR technology was used to analyze the ratio of S. suis strains. The results suggest that the highly virulent serotype 2 ST1 strains are preferentially aerosolized and that the S. suis preferential aerosolization is a strain-dependent process. These observations will need to be confirmed using a larger number of strains. This study is a proof of concept and increases our knowledge on the potential aerosol transmission of S. suis.

  9. Genetic Instability in the Mating Type System of Tetrahymena pigmentosa

    PubMed Central

    Simon, Ellen M.; Orias, Eduardo

    1987-01-01

    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. PMID:3692137

  10. Trends in serotypes and sequence types among cases of invasive pneumococcal disease in Scotland, 1999-2010.

    PubMed

    Lamb, Karen E; Flasche, Stefan; Diggle, Mathew; Inverarity, Donald; Greenhalgh, David; Jefferies, Johanna M; Smith, Andrew; Edwards, Giles F S; Denham, Barbara; McMenamin, Jim; McDonald, Eisin; Mitchell, Tim J; Clarke, Stuart C; Robertson, Chris

    2014-07-23

    The 7-valent pneumococcal conjugate vaccine (Prevenar(®), Wyeth; PCV7) was introduced to the UK paediatric immunisation schedule in 2006. This study investigates trends in serotypes and multi locus sequence types (STs) among cases of invasive pneumococcal disease (IPD) in Scotland prior to, and following, the introduction of PCV7. Scottish Invasive Pneumococcal Disease Enhanced Surveillance has records of all cases of IPD in Scotland since 1999. Cases diagnosed from blood or cerebrospinal fluid isolates until 2010 were analysed. Logistic and poisson regression modelling was used to assess trends prior to and following the introduction of PCV7. Prior to PCV7 use, on average 650 cases of IPD were reported each year; 12% occurred in those aged <5 years and 35% affected those aged over 65 years. Serotypes in PCV7 represented 47% of cases (68% in <5 year olds). The serotype and ST distribution was relatively stable with only serotype 1 and associated ST 306 showing an increasing trend. PCV7 introduction was associated with a 69% (95% CI: 50%, 80%) reduction in the incidence of IPD among those aged <5 years, a 57% (95% CI: 47%, 66%) reduction among those aged 5-64 years but no significant change among those aged 65 years and over where increases in non-PCV7 serotypes were observed. Serotypes which became more prevalent post-PCV7 are those which were associated with STs related to the PCV7 serotypes. Routine serotyping and sequence typing in Scotland allowed the assessment of the relationship between the capsule and the clones in the post vaccination era. Changes in the distribution of serotypes post PCV7 introduction appear to be driven by associations between serotypes and STs prior to PCV7 introduction. This has implications for the possible effects of the introduction of higher valency vaccines and could aid in predicting replacement serotypes in IPD. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Serotyping of Toxoplasma gondii in Cats (Felis domesticus) Reveals Predominance of Type II Infections in Germany

    PubMed Central

    Maksimov, Pavlo; Zerweck, Johannes; Dubey, Jitender P.; Pantchev, Nikola; Frey, Caroline F.; Maksimov, Aline; Reimer, Ulf; Schutkowski, Mike; Hosseininejad, Morteza; Ziller, Mario; Conraths, Franz J.; Schares, Gereon

    2013-01-01

    Background Cats are definitive hosts of Toxoplasma gondii and play an essential role in the epidemiology of this parasite. The study aims at clarifying whether cats are able to develop specific antibodies against different clonal types of T. gondii and to determine by serotyping the T. gondii clonal types prevailing in cats as intermediate hosts in Germany. Methodology To establish a peptide-microarray serotyping test, we identified 24 suitable peptides using serological T. gondii positive (n=21) and negative cat sera (n=52). To determine the clonal type-specific antibody response of cats in Germany, 86 field sera from T. gondii seropositive naturally infected cats were tested. In addition, we analyzed the antibody response in cats experimentally infected with non-canonical T. gondii types (n=7). Findings Positive cat reference sera reacted predominantly with peptides harbouring amino acid sequences specific for the clonal T. gondii type the cats were infected with. When the array was applied to field sera from Germany, 98.8% (85/86) of naturally-infected cats recognized similar peptide patterns as T. gondii type II reference sera and showed the strongest reaction intensities with clonal type II-specific peptides. In addition, naturally infected cats recognized type II-specific peptides significantly more frequently than peptides of other type-specificities. Cats infected with non-canonical types showed the strongest reactivity with peptides presenting amino-acid sequences specific for both, type I and type III. Conclusions Cats are able to mount a clonal type-specific antibody response against T. gondii. Serotyping revealed for most seropositive field sera patterns resembling those observed after clonal type II-T. gondii infection. This finding is in accord with our previous results on the occurrence of T. gondii clonal types in oocysts shed by cats in Germany. PMID:24244652

  12. Erysipelothrix spp. genotypes, serotypes, and surface protective antigen types associated with abattoir condemnations.

    PubMed

    Bender, Joseph S; Irwin, Christa K; Shen, Hui-Gang; Schwartz, Kent J; Opriessnig, Tanja

    2011-01-01

    The objective of the current study was to investigate characteristics of Erysipelothrix spp. from slaughter condemnations. Specimens from 70 carcasses with lesions suspect for swine erysipelas were collected at an abattoir in Iowa from October 2007 to February 2009. Erysipelothrix spp. were isolated from 59 of 70 carcasses (84.3%). Abattoir inspectors classified lesions as acute, subacute, or chronic; 8 of 8 (100%) were acute cases, 31 of 32 (96.9%) were subacute cases, and 20 of 30 (66.6%) were chronic cases that were isolation positive. The following serotypes were identified: 1a (40.7%; 24/59), 2 (49.2%; 29/59), 7 (1/59), 10 (1/59), 11 (1/59), and untypeable (5.1%; 3/59). Serotypes 1a and 2 were identified in pigs with acute, subacute, or chronic clinical manifestations, whereas serotypes 7, 10, and 11 were only present in chronic cases. Fifty-seven of the 59 isolates were determined to belong to E. rhusiopathiae, and 2 of 59 of the isolates were determined to be E. tonsillarum by multiplex real-time polymerase chain reaction. Surface protective antigen (spa) A was detected in all E. rhusiopathiae isolates but not in E. tonsillarum serotypes 7 and 10. The results of the present study indicate that E. rhusiopathiae serotypes 1a and 2 continue to be commonly isolated from condemned pig carcasses and that spaA is the exclusive spa type in U.S. abattoir isolates. Interestingly, E. tonsillarum, thought to be avirulent for swine, was isolated from systemic sites from 3.4% of the carcasses that were negative for E. rhusiopathiae, indicating the potential importance of this genotype in erysipelas pathogenesis.

  13. Evolution of Mating Systems in Basidiomycetes and the Genetic Architecture Underlying Mating-Type Determination in the Yeast Leucosporidium scottii

    PubMed Central

    Maia, Teresa M.; Lopes, Susana T.; Almeida, João M. G. C. F.; Rosa, Luiz H.; Sampaio, José Paulo; Gonçalves, Paula; Coelho, Marco A.

    2015-01-01

    In most fungi, sexual reproduction is bipolar; that is, two alternate sets of genes at a single mating-type (MAT) locus determine two mating types. However, in the Basidiomycota, a unique (tetrapolar) reproductive system emerged in which sexual identity is governed by two unlinked MAT loci, each of which controls independent mechanisms of self/nonself recognition. Tetrapolar-to-bipolar transitions have occurred on multiple occasions in the Basidiomycota, resulting, for example, from linkage of the two MAT loci into a single inheritable unit. Nevertheless, owing to the scarcity of molecular data regarding tetrapolar systems in the earliest-branching lineage of the Basidiomycota (subphylum Pucciniomycotina), it is presently unclear if the last common ancestor was tetrapolar or bipolar. Here, we address this question, by investigating the mating system of the Pucciniomycotina yeast Leucosporidium scottii. Using whole-genome sequencing and chromoblot analysis, we discovered that sexual reproduction is governed by two physically unlinked gene clusters: a multiallelic homeodomain (HD) locus and a pheromone/receptor (P/R) locus that is biallelic, thereby dismissing the existence of a third P/R allele as proposed earlier. Allele distribution of both MAT genes in natural populations showed that the two loci were in strong linkage disequilibrium, but independent assortment of MAT alleles was observed in the meiotic progeny of a test cross. The sexual cycle produces fertile progeny with similar proportions of the four mating types, but approximately 2/3 of the progeny was found to be nonhaploid. Our study adds to others in reinforcing tetrapolarity as the ancestral state of all basidiomycetes. PMID:26178967

  14. Dynamics of mitochondrial inheritance in the evolution of binary mating types and two sexes.

    PubMed

    Hadjivasiliou, Zena; Lane, Nick; Seymour, Robert M; Pomiankowski, Andrew

    2013-10-22

    The uniparental inheritance (UPI) of mitochondria is thought to explain the evolution of two mating types or even true sexes with anisogametes. However, the exact role of UPI is not clearly understood. Here, we develop a new model, which considers the spread of UPI mutants within a biparental inheritance (BPI) population. Our model explicitly considers mitochondrial mutation and selection in parallel with the spread of UPI mutants and self-incompatible mating types. In line with earlier work, we find that UPI improves fitness under mitochondrial mutation accumulation, selfish conflict and mitonuclear coadaptation. However, we find that as UPI increases in the population its relative fitness advantage diminishes in a frequency-dependent manner. The fitness benefits of UPI 'leak' into the biparentally reproducing part of the population through successive matings, limiting the spread of UPI. Critically, while this process favours some degree of UPI, it neither leads to the establishment of linked mating types nor the collapse of multiple mating types to two. Only when two mating types exist beforehand can associated UPI mutants spread to fixation under the pressure of high mitochondrial mutation rate, large mitochondrial population size and selfish mutants. Variation in these parameters could account for the range of UPI actually observed in nature, from strict UPI in some Chlamydomonas species to BPI in yeast. We conclude that UPI of mitochondria alone is unlikely to have driven the evolution of two mating types in unicellular eukaryotes.

  15. Multiple Clones within Multidrug-Resistant Salmonella enterica Serotype Typhimurium Phage Type DT104

    PubMed Central

    Markogiannakis, Antonis; Tassios, Panayotis T.; Lambiri, Maria; Ward, Linda R.; Kourea-Kremastinou, Jenny; Legakis, Nicholas J.; Vatopoulos, Alkiviadis C.

    2000-01-01

    Six distinct clones were present among Greek multidrug-resistant Salmonella enterica serotype Typhimurium phage type DT104, since isolates belonging to resistance phenotypes including the ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) core could be distinguished with respect to their pulsed-field gel electrophoresis patterns, int1 integron structures, and presence or absence of antibiotic resistance genes ant(3")-Ia, pse-1, and tem-1. PMID:10699039

  16. Presence of alpha and a mating types in environmental and clinical collections of Cryptococcus neoformans var. gattii strains from Australia.

    PubMed

    Halliday, C L; Bui, T; Krockenberger, M; Malik, R; Ellis, D H; Carter, D A

    1999-09-01

    Cryptococcus neoformans var. gattii lives in association with certain species of eucalyptus trees and is a causative agent of cryptococcosis. It exists as two mating types, MATalpha and MATa, which is determined by a single-locus, two-allele system. In the closely related C. neoformans var. neoformans, the alpha mating type has been found to outnumber its a counterpart by at least 30:1, but there have been very limited data on the proportions of each mating type in C. neoformans var. gattii. In the present study, specific PCR primers were designed to amplify two separate alpha-mating-type genes from C. neoformans var. gattii strains. These were used to survey for the presence of the two mating types in clinical and environmental collections of C. neoformans var. gattii strains from Australia. Sixty-eight of 69 clinical isolates produced both alpha mating type-specific bands and were assumed to be of the alpha mating type. The majority of environmental isolates were also of the alpha mating type, but the a mating type was located in two separate areas. In one area, the a mating type outnumbered the alpha mating type by 27:2, but in the second area, the ratio of the two mating types was close to the 50:50 ratio expected for sexual recombination.

  17. Evolution of sexes from an ancestral mating-type specification pathway.

    PubMed

    Geng, Sa; De Hoff, Peter; Umen, James G

    2014-07-01

    Male and female sexes have evolved repeatedly in eukaryotes but the origins of dimorphic sexes and their relationship to mating types in unicellular species are not understood. Volvocine algae include isogamous species such as Chlamydomonas reinhardtii, with two equal-sized mating types, and oogamous multicellular species such as Volvox carteri with sperm-producing males and egg-producing females. Theoretical work predicts genetic linkage of a gamete cell-size regulatory gene(s) to an ancestral mating-type locus as a possible step in the evolution of dimorphic gametes, but this idea has not been tested. Here we show that, contrary to predictions, a single conserved mating locus (MT) gene in volvocine algae-MID, which encodes a RWP-RK domain transcription factor-evolved from its ancestral role in C. reinhardtii as a mating-type specifier, to become a determinant of sperm and egg development in V. carteri. Transgenic female V. carteri expressing male MID produced functional sperm packets during sexual development. Transgenic male V. carteri with RNA interference (RNAi)-mediated knockdowns of VcMID produced functional eggs, or self-fertile hermaphrodites. Post-transcriptional controls were found to regulate cell-type-limited expression and nuclear localization of VcMid protein that restricted its activity to nuclei of developing male germ cells and sperm. Crosses with sex-reversed strains uncoupled sex determination from sex chromosome identity and revealed gender-specific roles for male and female mating locus genes in sexual development, gamete fitness and reproductive success. Our data show genetic continuity between the mating-type specification and sex determination pathways of volvocine algae, and reveal evidence for gender-specific adaptations in the male and female mating locus haplotypes of Volvox. These findings will enable a deeper understanding of how a master regulator of mating-type determination in an ancestral unicellular species was reprogrammed to

  18. Analysis of Molecular Epidemiology of Chilean Salmonella enterica Serotype Enteritidis Isolates by Pulsed-Field Gel Electrophoresis and Bacteriophage Typing

    PubMed Central

    Fernandez, Jorge; Fica, Alberto; Ebensperger, German; Calfullan, Hector; Prat, Soledad; Fernandez, Alda; Alexandre, Marcela; Heitmann, Ingrid

    2003-01-01

    Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype

  19. Mating type gene (MAT1-1) in Japanese isolates of Trichophyton rubrum.

    PubMed

    Kano, Rui; Isizuka, Maiko; Hiruma, Masataro; Mochizuki, Takashi; Kamata, Hiroshi; Hasegawa, Atsuhiko

    2013-02-01

    Trichophyton rubrum is an anthropophilic species that is the most frequent etiologic agent of human dermatophytosis throughout the world. No teleomorph has been identified for T. rubrum strains. This study used PCR analysis to confirm the presence of a mating type locus in the genome of Japanese isolates of T. rubrum. To clarify the epidemiological and ecological characteristics of this fungus, mating type sequences were tested for correlation of MAT genotype to mating type. This study examined clinical isolates of T. rubrum that had been obtained from 206 human cases of tinea pedis and tinea unguium in Japan, including those from Fukuoka (29 strains), Gifu (23 strains), Kanazawa (63 strains), and Tokyo (91 strains), along with 10 isolates derived from 10 cases of canine dermatophytosis. PCR detected the presence of MAT1-1 in all of the human and animal isolates. Therefore, all isolates examined were expected to react as (-) type on the mating test and not as (+) type.

  20. Rearrangements of the transposable mating-type cassettes of fission yeast.

    PubMed Central

    Beach, D H; Klar, A J

    1984-01-01

    The fission yeast, Schizosaccharomyces pombe, switches mating type every few cell divisions. Switching is controlled by the genes of the mating-type locus, which consists of three components, mat1, mat2-P and mat3-M, each separated by approximately 15 kb. Copy transposition of P (Plus) or M (Minus) information from mat2-P or mat3-M into the expression locus mat1 mediates cell type switching. The mating-type locus undergoes events at high frequency (10(-2)-10(-6)) which stabilize one or other mating type. These events are shown to be rearrangements which result in either deletion or insertion of DNA between cassettes. Images Fig. 3. Fig. 5. Fig. 7. Fig. 8. PMID:6325178

  1. Multilocus Sequence Typing as a Replacement for Serotyping in Salmonella enterica

    PubMed Central

    Zhou, Zhemin; Sangal, Vartul; Krauland, Mary G.; Hale, James L.; Harbottle, Heather; Uesbeck, Alexandra; Dougan, Gordon; Harrison, Lee H.; Brisse, Sylvain

    2012-01-01

    Salmonella enterica subspecies enterica is traditionally subdivided into serovars by serological and nutritional characteristics. We used Multilocus Sequence Typing (MLST) to assign 4,257 isolates from 554 serovars to 1092 sequence types (STs). The majority of the isolates and many STs were grouped into 138 genetically closely related clusters called eBurstGroups (eBGs). Many eBGs correspond to a serovar, for example most Typhimurium are in eBG1 and most Enteritidis are in eBG4, but many eBGs contained more than one serovar. Furthermore, most serovars were polyphyletic and are distributed across multiple unrelated eBGs. Thus, serovar designations confounded genetically unrelated isolates and failed to recognize natural evolutionary groupings. An inability of serotyping to correctly group isolates was most apparent for Paratyphi B and its variant Java. Most Paratyphi B were included within a sub-cluster of STs belonging to eBG5, which also encompasses a separate sub-cluster of Java STs. However, diphasic Java variants were also found in two other eBGs and monophasic Java variants were in four other eBGs or STs, one of which is in subspecies salamae and a second of which includes isolates assigned to Enteritidis, Dublin and monophasic Paratyphi B. Similarly, Choleraesuis was found in eBG6 and is closely related to Paratyphi C, which is in eBG20. However, Choleraesuis var. Decatur consists of isolates from seven other, unrelated eBGs or STs. The serological assignment of these Decatur isolates to Choleraesuis likely reflects lateral gene transfer of flagellar genes between unrelated bacteria plus purifying selection. By confounding multiple evolutionary groups, serotyping can be misleading about the disease potential of S. enterica. Unlike serotyping, MLST recognizes evolutionary groupings and we recommend that Salmonella classification by serotyping should be replaced by MLST or its equivalents. PMID:22737074

  2. Two tightly linked silent cassettes in the mating-type region of Schizosaccharomyces pombe.

    PubMed

    Egel, R

    1984-04-01

    Genetic evidence is presented for the presence of two silent cassettes mat2-P and mat3- M, which both map to the right of the expressible site mat1 of the mating-type region in Schizosaccharomyces pombe. During a switch of mating type, the resident cassette at mat1 is replaced by a copy of opposite mating-type information from one of the silent loci. Usually the switch becomes effective in one of two daughter cells, thus allowing for efficient sister-cell conjugation. In swi mutants, mating-type switching can be observed as early as for the first division after spore germination, albeit at a lower frequency. Genetically the two silent cassettes are linked so tightly that no crossovers were observed between mat2 and mat3 at a resolution of 10(-3) cM.

  3. Pseudohomothallism and evolution of the mating-type chromosome in Neurospora tetrasperma

    SciTech Connect

    Merino, S.T.; Nelson, M.A.; Natvig, D.O.

    1996-06-01

    Ascospores of Neurospora tetrasperma normally contain nuclei of both mating-type idiomorphs (a and A), resulting in self-fertile heterokaryons (a type of sexual reproduction termed pseudohomothallism). Occasional homokaryotic self-sterile strains (either a or A) behave as heterothallics and, in principal, provide N. tetrasperma to assess levels of intrastrain heterokaryosis (heterozygosity). The unexpected result was the mating-type chromosome and autosomes exhibited very different patterns of evolution, apparently because of suppressed recombination between mating-type chromosomes. Analysis of sequences on the mating-type chromosomes of wild-collected self-fertile strains revealed high levels of genetic variability between sibling A and a nuclei. In contrast, sequences on autosomes of sibling A and a nuclei exhibited nearly complete homogeneity. Conservation of distinct haplotype combinations on A and a mating-type chromosomes in strains from diverse locations further suggested an absence of recombination over substantial periods of evolutionary time. The suppression of recombination of the N. tetrasperma mating-type chromosome, expected to ensure a high frequency of self fertility, presents an interesting parallel with, and possible model for studying aspects of, the evolution of mammalian sex chromosomes. 39 refs., 5 figs., 1 tab.

  4. Fission yeast switches mating type by a replication–recombination coupled process

    PubMed Central

    Arcangioli, Benoit; de Lahondès, Raynald

    2000-01-01

    Fission yeast exhibits a homothallic life cycle, in which the mating type of the cell mitotically alternates in a highly regulated fashion. Pedigree analysis of dividing cells has shown that only one of the two sister cells switches mating type. It was shown recently that a site- and strand-specific DNA modification at the mat1 locus precedes mating-type switching. By tracking the fate of mat1 DNA throughout the cell cycle with a PCR assay, we identified a novel DNA intermediate of mating-type switching in S-phase. The time and rate of appearance and disappearance of this DNA intermediate are consistent with a model in which mating-type switching occurs through a replication–recombination coupled pathway. Such a process provides experimental evidence in support of a copy choice recombination model in Schizosaccharomyces pombe mating-type switching and is reminiscent of the sister chromatid recombination used to complete replication in the presence of certain types of DNA damage. PMID:10716938

  5. Differentiation between Atypical Isolates of Candida lusitaniae and Candida pulcherrima by Determination of Mating Type

    PubMed Central

    Noël, Thierry; Favel, Anne; Michel-Nguyen, Annie; Goumar, Abdelhak; Fallague, Karim; Chastin, Christiane; Leclerc, Florence; Villard, Jean

    2005-01-01

    We report on five clinical isolates routinely identified as Candida lusitaniae that the ID 32C system was unable to discriminate from the closely related species Candida pulcherrima. When additional tests did not allow accurate identification, the less usual mating type test identified all of them as Clavispora lusitaniae. Mating type testing appears to be a valuable tool for assessing the true incidence of this emerging non-albicans Candida species. PMID:15750124

  6. Mutations Affecting Donor Preference during Mating Type Interconversion in Saccharomyces Cerevisiae

    PubMed Central

    Weiler, K. S.; Szeto, L.; Broach, J. R.

    1995-01-01

    Homothallic strains of Saccharomyces cerevisiae can convert mating type from a to α or α to a as often as every generation, by replacing genetic information specifying one mating type at the expressor locus, MAT, with information specifying the opposite mating type. The cryptic mating type information that is copied and inserted at MAT is contained in either of two loci, HML or HMR. The particular locus selected as donor during mating type interconversion is regulated by the allele expressed at MAT. MATa cells usually select HML, and MATα cells usually select HMR, a process referred to as donor preference. To identify factors required for donor preference, we isolated and characterized a number of mutants that frequently selected the nonpreferred donor locus during mating type interconversion. Many of these mutants were found to harbor chromosome rearrangements or mutations at MAT or HML that interfered with the switching process. However, one mutant carried a recessive allele of CHL1, a gene previously shown to be required for efficient chromosome segregation during mitosis. Homothallic strains of yeast containing a null allele of CHL1 exhibited almost random selection of the donor locus in a MATa background but were normal in their ability to select HMR in a MATα background. Our results indicate that Chl1p participates in the process of donor selection and are consistent with a model in which Chl1p helps establish an intrinsic bias in donor preference. PMID:7789755

  7. Characterization and distribution of mating type genes in the dothistroma needle blight pathogens.

    PubMed

    Groenewald, Marizeth; Barnes, Irene; Bradshaw, Rosie E; Brown, Anna V; Dale, Angie; Groenewald, Johannes Z; Lewis, Kathy J; Wingfield, Brenda D; Wingfield, Michael J; Crous, Pedro W

    2007-07-01

    ABSTRACT Dothistroma septosporum and D. pini are the two causal agents of Dothistroma needle blight of Pinus spp. in natural forests and plantations. Degenerate primers amplified portions of mating type genes (MAT1-1-1 and MAT1-2) and chromosome walking was applied to obtain the full-length genes in both species. The mating-type-specific primers designed in this study could distinguish between the morphologically similar D. pini and D. septosporum and between the different mating types of these species. Screening of isolates from global collections of D. septosporum showed that only MAT2 isolates are present in Australian and New Zealand collections, where only the asexual form of the fungus has been found. In contrast, both mating types of D. septosporum were present in collections from Canada and Europe, where the sexual state is known. Intriguingly, collections from South Africa and the United Kingdom, where the sexual state of the fungus is unknown, included both mating types. In D. pini, for which no teleomorph is known, both mating types were present in collections from the United States. These results provided new insights into the biology and global distribution of two of the world's most important pine pathogens and should facilitate management of the diseases caused by these fungi.

  8. B cell response during infection with the MAT a and MAT alpha mating types of Cryptococcus neoformans.

    PubMed

    Rodrigues, Adila Regina T Santos; Heise, Norton; Previato, José Osvaldo; Mendonça-Previato, Lucia; Peçanha, Ligia M T

    2005-01-01

    In the present study, we compared the B cell response of BALB/c and C57Bl/6 mice during Cryptococcus neoformans infection. This response was investigated using virulent serotype D forms of mating types alpha and a (MAT alpha and MAT a). C57Bl/6 mice showed massive (mainly cerebral) infection by both types, while BALB/c were resistant to infection. Some resistance of C57Bl/6 mice was induced by previous immunization with the capsular polysaccharide from MAT alpha. Passive immunization of C57Bl/6 mice with purified antibody (Ab) obtained from capsular polysaccharide-immunized mice also increased resistance to infection. Both mouse strains showed comparable low IgM response to the capsular polysaccharide from MAT alpha, and only C57Bl/6 mice produced IgM to the polysaccharide of MAT a. Comparable levels of different immunoglobulin (Ig) isotypes against capsular components of MAT alpha and MAT a were detected, and the response of C57Bl/6 mice was higher when compared to that of BALB/c mice. FACS analysis indicated an increase in the percentage of a high-granulosity (side-scatter) splenic subpopulation and in the percentage of splenic Gr-1+ cells in infected C57Bl/6 mice. In addition, the percentage of follicular splenic B cells was decreased after C. neoformans infection of C57Bl/6 mice. This response was more pronounced when we investigated infection induced by the MAT a mating type. Taken together, our results indicate that capsular polysaccharide derived from MAT alpha and MAT a types of C. neoformans have a stimulatory effect upon B cells but that there is no correlation between resistance of BALB/c mice and Ab production. However, the increase in resistance of C57Bl/6 mice parallels the production of Abs and a major change in splenic cell populations.

  9. Sex in smut fungi: Structure, function and evolution of mating-type complexes.

    PubMed

    Bakkeren, Guus; Kämper, Jörg; Schirawski, Jan

    2008-08-01

    Smut fungi are basidiomycete plant pathogens that pose a threat to many important cereal crops. In order to be pathogenic on plants, smut fungal cells of compatible mating-type need to fuse. Fusion and pathogenicity are regulated by two loci, a and b, which harbor conserved genes. The functions of the encoded mating-type complexes have been well-studied in the model fungus Ustilago maydis and will be briefly reviewed here. Sequence comparison of the mating-type loci of different smut and related fungi has revealed that these loci differ substantially in structure. These structural differences point to an evolution from tetrapolar to bipolar mating behavior, which might have occurred several independent times during fungal speciation.

  10. Identification of the Mating-Type (MAT) Locus That Controls Sexual Reproduction of Blastomyces dermatitidis

    PubMed Central

    Li, Wenjun; Sullivan, Thomas D.; Walton, Eric; Averette, Anna Floyd; Sakthikumar, Sharadha; Cuomo, Christina A.; Klein, Bruce S.

    2013-01-01

    Blastomyces dermatitidis is a dimorphic fungal pathogen that primarily causes blastomycosis in the midwestern and northern United States and Canada. While the genes controlling sexual development have been known for a long time, the genes controlling sexual reproduction of B. dermatitidis (teleomorph, Ajellomyces dermatitidis) are unknown. We identified the mating-type (MAT) locus in the B. dermatitidis genome by comparative genomic approaches. The B. dermatitidis MAT locus resembles those of other dimorphic fungi, containing either an alpha-box (MAT1-1) or an HMG domain (MAT1-2) gene linked to the APN2, SLA2, and COX13 genes. However, in some strains of B. dermatitidis, the MAT locus harbors transposable elements (TEs) that make it unusually large compared to the MAT locus of other dimorphic fungi. Based on the MAT locus sequences of B. dermatitidis, we designed specific primers for PCR determination of the mating type. Two B. dermatitidis isolates of opposite mating types were cocultured on mating medium. Immature sexual structures were observed starting at 3 weeks of coculture, with coiled-hyphae-containing cleistothecia developing over the next 3 to 6 weeks. Genetic recombination was detected in potential progeny by mating-type determination, PCR-restriction fragment length polymorphism (PCR-RFLP), and random amplification of polymorphic DNA (RAPD) analyses, suggesting that a meiotic sexual cycle might have been completed. The F1 progeny were sexually fertile when tested with strains of the opposite mating type. Our studies provide a model for the evolution of the MAT locus in the dimorphic and closely related fungi and open the door to classic genetic analysis and studies on the possible roles of mating and mating type in infection and virulence. PMID:23143684

  11. Interaction between mating-type proteins from the homothallic fungus Sordaria macrospora.

    PubMed

    Jacobsen, Sabine; Wittig, Michael; Pöggeler, Stefanie

    2002-06-01

    Mating-type genes control sexual development in ascomycetes. Little is known about their function in homothallic species, which are self-fertile and do not require a mating partner for sexual reproduction. The function of mating-type genes in the homothallic fungus Sordaria macrospora was assayed using a yeast system in order to find properties typical of eukaryotic transcription factors. We were able to demonstrate that the mating-type proteins SMTA-1 and SMTa-1 have domains capable of activating transcription of yeast reporter genes. Two-hybrid analysis for heterodimerization and homodimerization revealed the ability of SMTA-1 to interact with SMTa-1 and vice versa. These two proteins are encoded by different mating types in the related heterothallic species Neurospora crassa. The interaction between SMTA-1 and SMTa-1 was defined by experiments with truncated versions of SMTA-1 and in vitro by means of protein cross-linking. Moreover, we gained evidence for homodimerization of SMTA-1. Possible functions of mating-type proteins in the homothallic ascomycete S. macrospora are discussed.

  12. Occurrence and Distribution of Mating Types of Pseudoperonospora cubensis in the United States.

    PubMed

    Thomas, Anna; Carbone, Ignazio; Cohen, Yigal; Ojiambo, Peter S

    2017-03-01

    During the past two decades, a resurgence of cucurbit downy mildew has occurred around the world, resulting in severe disease epidemics. In the United States, resurgence of the disease occurred in 2004 and several hypotheses, including introduction of a new genetic recombinant or pathotype of the pathogen, have been suggested as potential causes for this resurgence. Occurrence and distribution of mating types of Pseudoperonospora cubensis in the United States were investigated using 40 isolates collected from cucurbits across 11 states from 2005 to 2013. Pairing of unknown isolates with known mating-type tester strains on detached leaves of cantaloupe or cucumber resulted in oospore formation 8 to 10 days after inoculation. Isolates differed in their ability to form oospores across all coinoculation pairings, with oospore numbers ranging from 280 to 1,000 oospores/cm(2) of leaf tissue. Oospores were hyaline to golden-yellow, spherical, and approximately 36 μm in diameter. Of the 40 isolates tested, 24 were found to be of the A1 mating type, while 16 were of the A2 mating type. Mating type was significantly (P < 0.0001) associated with host type, whereby all isolates collected from cucumber were of the A1 mating type, while isolates from squash and watermelon were of the A2 mating type. Similarly, mating type was significantly (P = 0.0287) associated with geographical region, where isolates from northern-tier states of Michigan, New Jersey, New York, and Ohio were all A1, while isolates belonging to either A1 or A2 mating type were present in equal proportions in southern-tier states of Alabama, Florida, Georgia, North Carolina, South Carolina, and Texas. Viability assays showed that oospores were viable and, on average, approximately 40% of the oospores produced were viable as determined by the plasmolysis method. This study showed that A1 and A2 mating types of P. cubensis are present and the pathogen could potentially reproduce sexually in cucurbits within the

  13. Antibodies Directed against Shiga-Toxin Producing Escherichia coli Serotype O103 Type III Secreted Proteins Block Adherence of Heterologous STEC Serotypes to HEp-2 Cells

    PubMed Central

    Desin, Taseen S.; Townsend, Hugh G.; Potter, Andrew A.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O103 is a zoonotic pathogen that is capable of causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. The main animal reservoir for STEC is ruminants and hence reducing the levels of this pathogen in cattle could ultimately lower the risk of STEC infection in humans. During the process of infection, STECO103 uses a Type III Secretion System (T3SS) to secrete effector proteins (T3SPs) that result in the formation of attaching and effacing (A/E) lesions. Vaccination of cattle with STEC serotype O157 T3SPs has previously been shown to be effective in reducing shedding of STECO157 in a serotype-specific manner. In this study, we tested the ability of rabbit polyclonal sera against individual STECO103 T3SPs to block adherence of the organism to HEp-2 cells. Our results demonstrate that pooled sera against EspA, EspB, EspF, NleA and Tir significantly lowered the adherence of STECO103 relative to pre-immune sera. Likewise, pooled anti-STECO103 sera were also able to block adherence by STECO157. Vaccination of mice with STECO103 recombinant proteins induced strong IgG antibody responses against EspA, EspB, NleA and Tir but not against EspF. However, the vaccine did not affect fecal shedding of STECO103 compared to the PBS vaccinated group over the duration of the experiment. Cross reactivity studies using sera against STECO103 recombinant proteins revealed a high degree of cross reactivity with STECO26 and STECO111 proteins implying that sera against STECO103 proteins could potentially provide neutralization of attachment to epithelial cells by heterologous STEC serotypes. PMID:26451946

  14. Mating-type genes from the homothallic fungus Sordaria macrospora are functionally expressed in a heterothallic ascomycete.

    PubMed

    Pöggeler, S; Risch, S; Kück, U; Osiewacz, H D

    1997-10-01

    Homokaryons from the homothallic ascomycte Sordaria macrospora are able to enter the sexual pathway and to form fertile fruiting bodies. To analyze the molecular basis of homothallism and to elucidate the role of mating-products during fruiting body development, we cloned and sequenced the entire S. macrospora mating-type locus. Comparison of the Sordaria mating-type locus with mating-type idiomorphs from the heterothallic ascomycetes Neurospora crassa and Podospora anserina revealed that sequences from both idiomorphs (A/a and mat-/mat+, respectively) are contiguous in S. macrospora. DNA sequencing of the S. macrospora mating-type region allowed the identification of four open reading frames (ORFs), which were termed Smt-a1, SmtA-1, SmtA-2 and SmtA-3. While Smt-a1, SmtA-1, and SmtA-2 show strong sequence similarities with the corresponding N. crassa mating-type ORFs, SmtA-3 has a chimeric character. It comprises sequences that are similar to the A and a mating-type idiomorph from N. crassa. To determine functionality of the S. macrospora mating-type genes, we show that all ORFs are transcriptionally expressed. Furthermore, we transformed the S. macrospora mating-type genes into mat- and mat+ strains of the closely related heterothallic fungus P. anserina. The transformation experiments show that mating-type genes from S. macrospora induce fruiting body formation in P. anserina.

  15. Roles for receptors, pheromones, G proteins, and mating type genes during sexual reproduction in Neurospora crassa.

    PubMed

    Kim, Hyojeong; Wright, Sara J; Park, Gyungsoon; Ouyang, Shouqiang; Krystofova, Svetlana; Borkovich, Katherine A

    2012-04-01

    Here we characterize the relationship between the PRE-2 pheromone receptor and its ligand, CCG-4, and the general requirements for receptors, pheromones, G proteins, and mating type genes during fusion of opposite mating-type cells and sexual sporulation in the multicellular fungus Neurospora crassa. PRE-2 is highly expressed in mat a cells and is localized in male and female reproductive structures. Δpre-2 mat a females do not respond chemotropically to mat A males (conidia) or form mature fruiting bodies (perithecia) or meiotic progeny (ascospores). Strains with swapped identity due to heterologous expression of pre-2 or ccg-4 behave normally in crosses with opposite mating-type strains. Coexpression of pre-2 and ccg-4 in the mat A background leads to self-attraction and development of barren perithecia without ascospores. Further perithecial development is achieved by inactivation of Sad-1, a gene required for meiotic gene silencing. Findings from studies involving forced heterokaryons of opposite mating-type strains show that presence of one receptor and its compatible pheromone is necessary and sufficient for perithecial development and ascospore production. Taken together, the results demonstrate that although receptors and pheromones control sexual identity, the mating-type genes (mat A and mat a) must be in two different nuclei to allow meiosis and sexual sporulation to occur.

  16. Conservation of the b mating-type gene complex among bipolar and tetrapolar smut fungi.

    PubMed Central

    Bakkeren, G; Kronstad, J W

    1993-01-01

    In the phytopathogenic fungus Ustilago hordei, one locus with two alternate alleles, MAT-1 and MAT-2, controls mating and the establishment of the infectious dikaryon (bipolar mating). In contrast, for U. maydis, these functions are associated with two different gene complexes, called a and b (tetrapolar mating); the a complex has two alternate specificities, and the b gene complex is multiallelic. We have found homologs for the b gene complex in U. hordei and have cloned one from each mating type using sequences from one bEast allele of U. maydis as a probe. Sequence analysis revealed two divergent open reading frames in each b complex, which we called bW (bWest) and bE (bEast) in analogy with the b gene complex of U. maydis. The predicted bW and bE gene products from the two different mating types showed approximately 75% identity when homologous polypeptides were compared. All of the characterized bW and bE gene products have variable amino-terminal regions, conserved carboxy-terminal regions, and similar homeodomain motifs. Sequence comparisons with the bW1 and bE1 genes of U. maydis showed conservation in organization and structure. Transformation of the U. hordei b gene complex into a U. hordei strain of opposite mating type showed that the b genes from the two mating types are functional alleles. The U. hordei b genes, when introduced into U. maydis, rendered the haploid transformants weakly pathogenic on maize. These results indicate that structurally and functionally conserved b genes are present in U. hordei. PMID:8439742

  17. Cell-cell signalling in sexual chemotaxis: a basis for gametic differentiation, mating types and sexes.

    PubMed

    Hadjivasiliou, Zena; Iwasa, Yoh; Pomiankowski, Andrew

    2015-08-06

    While sex requires two parents, there is no obvious need for them to be differentiated into distinct mating types or sexes. Yet this is the predominate state of nature. Here, we argue that mating types could play a decisive role because they prevent the apparent inevitability of self-stimulation during sexual signalling. We rigorously assess this hypothesis by developing a model for signaller-detector dynamics based on chemical diffusion, chemotaxis and cell movement. Our model examines the conditions under which chemotaxis improves partner finding. Varying parameter values within ranges typical of protists and their environments, we show that simultaneous secretion and detection of a single chemoattractant can cause a multifold movement impediment and severely hinder mate finding. Mutually exclusive roles result in faster pair formation, even when cells conferring the same roles cannot pair up. This arrangement also allows the separate mating types to optimize their signalling or detecting roles, which is effectively impossible for cells that are both secretors and detectors. Our findings suggest that asymmetric roles in sexual chemotaxis (and possibly other forms of sexual signalling) are crucial, even without morphological differences, and may underlie the evolution of gametic differentiation among both mating types and sexes.

  18. Cell–cell signalling in sexual chemotaxis: a basis for gametic differentiation, mating types and sexes

    PubMed Central

    Hadjivasiliou, Zena; Iwasa, Yoh; Pomiankowski, Andrew

    2015-01-01

    While sex requires two parents, there is no obvious need for them to be differentiated into distinct mating types or sexes. Yet this is the predominate state of nature. Here, we argue that mating types could play a decisive role because they prevent the apparent inevitability of self-stimulation during sexual signalling. We rigorously assess this hypothesis by developing a model for signaller–detector dynamics based on chemical diffusion, chemotaxis and cell movement. Our model examines the conditions under which chemotaxis improves partner finding. Varying parameter values within ranges typical of protists and their environments, we show that simultaneous secretion and detection of a single chemoattractant can cause a multifold movement impediment and severely hinder mate finding. Mutually exclusive roles result in faster pair formation, even when cells conferring the same roles cannot pair up. This arrangement also allows the separate mating types to optimize their signalling or detecting roles, which is effectively impossible for cells that are both secretors and detectors. Our findings suggest that asymmetric roles in sexual chemotaxis (and possibly other forms of sexual signalling) are crucial, even without morphological differences, and may underlie the evolution of gametic differentiation among both mating types and sexes. PMID:26156301

  19. Serotypes, Antibiotic Susceptibilities, and Multi-Locus Sequence Type Profiles of Streptococcus agalactiae Isolates Circulating in Beijing, China

    PubMed Central

    Ma, Xiu-hua; Song, Feng-li; Fan, Ling; Guo, Cui-mei; Shi, Wei; Yu, Sang-jie; Yao, Kai-hu; Yang, Yong-hong

    2015-01-01

    Background To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections. Methods All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles. Results In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB. Conclusion S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB. PMID:25781346

  20. Isolation and in vitro binding of mating type plus fertilization tubules from Chlamydomonas.

    PubMed

    Wilson, Nedra F

    2008-01-01

    During fertilization in Chlamydomonas, adhesion and fusion of gametes occur at the tip of specialized regions of the plasma membrane, known as mating structures. The mating type minus (mt[-]) structure is a slightly raised dome-shaped region located at the apical end of the cell body. In contrast, the activated mating type plus (mt[+]) structure is an actin-filled, microvillouslike organelle. Interestingly, a similar type of "fusion organelle" is conserved across diverse groups. Chlamydomonas provides an ideal model system for studying the process of gametic cell fusion in that it is amenable to genetic manipulations as well as cell and molecular biological approaches. Moreover, the ease of culturing Chlamydomonas combined with the ability to isolate the mt(+) fertilization tubule and the development of in vitro assays for adhesion makes it an ideal system for biochemical studies focused on dissecting the molecular mechanisms that underlie the complex process of gametic cell fusion.

  1. Social amoebae mating types do not invest unequally in sexual offspring.

    PubMed

    Douglas, T E; Queller, D C; Strassmann, J E

    2017-05-01

    Unequal investment by different sexes in their progeny is common and includes differential investment in the zygote and differential care of the young. The social amoeba Dictyostelium discoideum has a sexual stage in which isogamous cells of any two of the three mating types fuse to form a zygote which then attracts hundreds of other cells to the macrocyst. The latter cells are cannibalized and so make no genetic contribution to reproduction. Previous literature suggests that this sacrifice may be induced in cells of one mating type by cells of another, resulting in a higher than expected production of macrocysts when the inducing type is rare and giving a reproductive advantage to this social cheat. We tested this hypothesis in eight trios of field-collected clones of each of the three D. discoideum mating types by measuring macrocyst production at different pairwise frequencies. We found evidence that supported differential contribution in only two of the 24 clone pairs, so this pattern is rare and clone-specific. In general, we did not reject the hypothesis that the mating types contribute cells relative to their proportion in the population. We also found a significant quadratic relationship between partner frequency and macrocyst production, suggesting that when one clone is rare, macrocyst production is limited by partner availability. We were also unable to replicate previous findings that macrocyst production could be induced in the absence of a compatible mating partner. Overall, mating type-specific differential investment during sex is unlikely in microbial eukaryotes like D. discoideum. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  2. Crystal Structure of Botulinum Neurotoxin Type G Light Chain - Serotype Divergence in Substrate Recognition†,‡

    PubMed Central

    Arndt, Joseph W.; Yu, Wayne; Bi, Fay; Stevens, Raymond C.

    2008-01-01

    The seven serotypes (A–G) of botulinum neurotoxins (BoNTs) block neurotransmitter release through their specific proteolysis of one of the three proteins of the soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) complex. BoNTs have stringent substrate specificities that are unique for metalloprotease in that they require exceptionally long substrates (1). In order to understand the molecular reasons for the unique specificities of the BoNTs, we determined the crystal structure of the catalytic light chain (LC) of Clostridium botulinum neurotoxin type G (BoNT/G-LC) at 2.35 Å resolution. The structure of BoNT/G-LC reveals a C-terminal β-sheet that is critical for LC oligomerization and is unlike that seen in the other LC structures. Its structural comparison with thermolysin and the available pool of LC structures reveals important serotype differences that are likely to be involved in substrate recognition of the P1’ residue. In addition, structural and sequence analysis have identified a potential exosite of BoNT/G-LC that recognizes a SNARE recognition motif of VAMP. PMID:16008342

  3. Crystal structure of botulinum neurotoxin type G light chain: serotype divergence in substrate recognition.

    PubMed

    Arndt, Joseph W; Yu, Wayne; Bi, Fay; Stevens, Raymond C

    2005-07-19

    The seven serotypes (A-G) of botulinum neurotoxins (BoNTs) block neurotransmitter release through their specific proteolysis of one of the three proteins of the soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) complex. BoNTs have stringent substrate specificities that are unique for metalloprotease in that they require exceptionally long substrates (1). To understand the molecular reasons for the unique specificities of the BoNTs, we determined the crystal structure of the catalytic light chain (LC) of Clostridium botulinum neurotoxin type G (BoNT/G-LC) at 2.35 A resolution. The structure of BoNT/G-LC reveals a C-terminal beta-sheet that is critical for LC oligomerization and is unlike that seen in the other LC structures. Its structural comparison with thermolysin and the available pool of LC structures reveals important serotype differences that are likely to be involved in substrate recognition of the P1' residue. In addition, structural and sequence analyses have identified a potential exosite of BoNT/G-LC that recognizes a SNARE recognition motif of VAMP.

  4. Alpha mating type-specific expression of mutations leading to constitutive agglutinability in Saccharomyces cerevisiae.

    PubMed Central

    Doi, S; Yoshimura, M

    1985-01-01

    Two mutants of Saccharomyces cerevisiae have been isolated and characterized. The mutants were constitutively agglutinable at 36 degrees C, the temperature at which wild-type cells agglutinate only after induction by mating pheromone. The mutant cells had other properties specific for the normal alpha cell type, i.e., conjugation with a cells, response to a mating pheromone, and production of alpha mating pheromone. The two mutations, cag1 and cag2, were recessive and expressed only in alpha cells. cag1 is linked very closely to the MAT locus, but cag2 is unlinked to the MAT locus. These cag mutations complemented ste3-1. These results indicate that CAG genes are novel alpha-specific genes involved in the regulation of sex agglutinin synthesis. PMID:3881403

  5. Gene activation by copy transposition in mating-type switching of a homothallic fission yeast.

    PubMed

    Egel, R; Gutz, H

    1981-04-01

    Mating-type switching in homothallic clones of the fission yeast, Schizosaccharomyces pombe, appears to follow the same route as previously found for "mutations" from homothallism to heterothallic ⊕ strains. A copy of mat2-P is transposed to and inserted at mat1, where it functionally replaces the mat1-M allele, and only the mat1 segment is expressed (!) to determine the actual mating type: mat1-M(!) mat2-P = ⊖ ⇌ ⊕ = mat1-P(!) mat2-P. This phenomenon has hitherto been concealed by the high switch-back rate from ⊕ to ⊖ observed in homothallic wild-type strains. It only becomes apparent in the presence of mutant "switching genes", which retard the rates of mating-type interconversion and temporarily freeze one or the other state of gene activation at the mat1 segment. Mutations to lowered rates of switching are found to map both inside and outside the mating-type locus. While the internal mutations of this kind exert their effect autonomously in the cis-configuration, the unlinked mutations are recessive to their wild-type alleles.

  6. The Chlamydomonas Mating Type Plus Fertilization Tubule, a Prototypic Cell Fusion Organelle: Isolation, Characterization, and In Vitro Adhesion to Mating Type Minus Gametes

    PubMed Central

    Wilson, Nedra F.; Foglesong, Mary J.; Snell, William J.

    1997-01-01

    In the biflagellated alga Chlamydomonas, adhesion and fusion of the plasma membranes of gametes during fertilization occurs via an actin-filled, microvillus-like cell protrusion. Formation of this ∼3-μm-long fusion organelle, the Chlamydomonas fertilization tubule, is induced in mating type plus (mt+) gametes during flagellar adhesion with mating type minus (mt−) gametes. Subsequent adhesion between the tip of the mt+ fertilization tubule and the apex of a mating structure on mt− gametes is followed rapidly by fusion of the plasma membranes and zygote formation. In this report, we describe the isolation and characterization of fertilization tubules from mt+ gametes activated for cell fusion. Fertilization tubules were detached by homogenization of activated mt+ gametes in an EGTA-containing buffer and purified by differential centrifugation followed by fractionation on sucrose and Percoll gradients. As determined by fluorescence microscopy of samples stained with a fluorescent probe for filamentous actin, the method yielded 2–3 × 106 fertilization tubules/μg protein, representing up to a 360-fold enrichment of these organelles. Examination by negative stain electron microscopy demonstrated that the purified fertilization tubules were morphologically indistinguishable from fertilization tubules on intact, activated mt+ gametes, retaining both the extracellular fringe and the internal array of actin filaments. Several proteins, including actin as well as two surface proteins identified by biotinylation studies, copurified with the fertilization tubules. Most importantly, the isolated mt+ fertilization tubules bound to the apical ends of activated mt− gametes between the two flagella, the site of the mt− mating structure; a single fertilization tubule bound per cell, binding was specific for gametes, and fertilization tubules isolated from trypsin-treated, activated mt+ gametes did not bind to activated mt− gametes. PMID:9199169

  7. Ascospore dimorphism-associated mating types of Sclerotinia trifoliorum equally capable of infecting chickpea

    USDA-ARS?s Scientific Manuscript database

    Sclerotinia trifoliorum causes stem and crown rot of chickpea and other forage and grain legumes, and is one of the three important species of the genus Sclerotinia. S. trifoliorum is unique from the other two species in that it is heterothallic and has two opposite mating types required for comple...

  8. Genes required for initiation and resolution steps of mating-type switching in fission yeast.

    PubMed

    Egel, R; Beach, D H; Klar, A J

    1984-06-01

    The fission yeast Schizosaccharomyces pombe switches mating type by transposition of a copy of DNA derived from either of the two storage cassettes, mat2 -P and mat3 -M, into the expression locus, mat1 . The recombinational event of switching is initiated by a double-stranded DNA break present in approximately 20% of the molecules at mat1 . Fifty-three mutants defective in switching of mating type have been isolated previously, and each has been assigned to 1 of 10 linkage groups. One group consists of cis-acting mutations at mat1 , which reduce the amount of the DNA double-strand cut. The remaining nine groups are mutations in genes that are unlinked to the mating-type locus and are studied here. Three ( swi1 , -3, -7) are required for formation of the double-strand cut, whereas the others are not. Mutants of three genes ( swi4 , -8, -9) undergo high-frequency rearrangement of the mating-type locus indicative of errors of resolution of recombinational intermediates. The remaining three ( swi2 , -5, -6) have normal levels of cut, do not make errors of resolution, and possibly are required either for efficient utilization of the cut or determining the directionality of switching. The data suggest that the switching process can be dissected into genetically distinguishable steps.

  9. Genes required for initiation and resolution steps of mating-type switching in fission yeast.

    PubMed Central

    Egel, R; Beach, D H; Klar, A J

    1984-01-01

    The fission yeast Schizosaccharomyces pombe switches mating type by transposition of a copy of DNA derived from either of the two storage cassettes, mat2 -P and mat3 -M, into the expression locus, mat1 . The recombinational event of switching is initiated by a double-stranded DNA break present in approximately 20% of the molecules at mat1 . Fifty-three mutants defective in switching of mating type have been isolated previously, and each has been assigned to 1 of 10 linkage groups. One group consists of cis-acting mutations at mat1 , which reduce the amount of the DNA double-strand cut. The remaining nine groups are mutations in genes that are unlinked to the mating-type locus and are studied here. Three ( swi1 , -3, -7) are required for formation of the double-strand cut, whereas the others are not. Mutants of three genes ( swi4 , -8, -9) undergo high-frequency rearrangement of the mating-type locus indicative of errors of resolution of recombinational intermediates. The remaining three ( swi2 , -5, -6) have normal levels of cut, do not make errors of resolution, and possibly are required either for efficient utilization of the cut or determining the directionality of switching. The data suggest that the switching process can be dissected into genetically distinguishable steps. Images PMID:6587363

  10. RAS/Cyclic AMP and Transcription Factor Msn2 Regulate Mating and Mating-Type Switching in the Yeast Kluyveromyces lactis ▿

    PubMed Central

    Barsoum, E.; Rajaei, N.; Åström, S. U.

    2011-01-01

    In response to harsh environmental conditions, ascomycetes produce stress-resistant spores to promote survival. As sporulation requires a diploid DNA content, species with a haploid lifestyle, such as Kluyveromyces lactis, first induce mating in response to stress. In K. lactis, mating and mating-type switching are induced by the DNA-binding protein Mts1. Mts1 expression is known to be upregulated by nutrient limitation, but the mechanism is unknown. We show that a ras2 mutation results in a hyperswitching phenotype. In contrast, strains lacking the phosphodiesterase Pde2 had lower switching rates compared to that of the wild type (WT). As Ras2 promotes cyclic AMP (cAMP) production and Pde2 degrades cAMP, these data suggest that low cAMP levels induce switching. Because the MTS1 regulatory region contains several Msn2 binding sites and Msn2 is a transcription factor that is activated by low cAMP levels, we investigated if Msn2 regulates MTS1 transcription. Consistently with this idea, an msn2 mutant strain displayed lower switching rates than the WT strain. The transcription of MTS1 is highly induced in the ras2 mutant strain. In contrast, an msn2 ras2 double mutant strain displays WT levels of the MTS1 transcript, showing that Msn2 is a critical inducer of MTS1 transcription. Strains lacking Msn2 and Pde2 also exhibit mating defects that can be complemented by the ectopic expression of Mts1. Finally, we show that MTS1 is subjected to negative autoregulation, presumably adding robustness to the mating and switching responses. We suggest a model in which Ras2/cAMP/Msn2 mediates the stress-induced mating and mating-type switching responses in K. lactis. PMID:21890818

  11. Population structure and mating type distribution of the chickpea blight pathogen Ascochyta rabiei from Pakistan and United States

    USDA-ARS?s Scientific Manuscript database

    Ascochyta blight caused by the fungus Ascochyta rabiei (AR) depresses chickpea production in Pakistan and worldwide. Thirty two AR isolates representing six geographical regions of Pakistan was compared with a US AR population for frequency of mating types and genetic variation. Mating type results ...

  12. Directed Replacement of Mt a by Mt a-1 Effects a Mating Type Switch in Neurospora Crassa

    PubMed Central

    Chang, S.; Staben, C.

    1994-01-01

    To test the functions of a mating type genes, we developed an efficient strategy to select transformants of Neurospora crassa in which resident A mating type DNA was replaced by cloned DNA from the mt a idiomorph. Cloned a idiomorphic DNA could specify all functions, including fertility, of a mating type, but only when it replaced A DNA at the mating type locus. Only the mt a-1 region of the a idiomorph was necessary in order to specify a mating type. Gene replacement events involved the homologous sequences flanking the unique mating type idiomorphic DNA, resulting in apparently isogenic a and A strains. These isogenic strains were fertile when crossed with one another, indicating that no determinants outside the transforming DNA are necessary for fertility as a and that no host sequences of A strains interfere with fertility as a. One a replacement strain bore a duplication of the transforming mt a-1 and hph DNA. The duplication strain had unexpected properties. Although mating type segregated 1:1 in crosses of this strain to A, the duplicated regions were efficiently altered during the sexual process to generate a single copy in the progeny. No progeny were recovered that had undergone RIP (repeat induced point mutation) sufficient to inactivate the mt a-1 gene. We infer that the mt a-1 gene is necessary and sufficient to specify a mating type identity in all vegetative and sexual activities. Mt a-1 may also play an essential role in ascosporogenesis after fertilization. PMID:8001795

  13. Four mating-type genes control sexual differentiation in the fission yeast.

    PubMed

    Kelly, M; Burke, J; Smith, M; Klar, A; Beach, D

    1988-05-01

    The mating-type region of fission yeast consists of three components, mat1, mat2-P and mat3-M, each separated by 15 kb. Cell-type is determined by the alternate allele present at mat1, either P in an h+ or M in an h- cell. mat2-P and mat3-M serve as donors of information that is transposed to mat1 during a switch of mating type. We have determined the nucleotide sequence of each component of mat. The P and M specific regions are 1104 and 1128 bp, respectively, and bounded by sequences common to each mating-type cassette (H1; 59 bp and H2; 135 bp). A third sequence is present at mat2-P and mat3-M but absent at mat1 (H3; 57 bp), and may be involved in transcriptional repression of these cassettes. mat1-P and mat1-M each encode two genes (Pc; 118 amino acids, Pi; 159 amino acids, Mc; 181 amino acids and Mi; 42 amino acids). Introduction of opal or frame-shift mutations into the open-reading-frame of each gene revealed that Pc and Mc are necessary and sufficient for mating and confer an h+ or h- mating type respectively. All four genes are required for meiotic competence in an h+/h- diploid. The transcription of each mat gene is strongly influenced by nutritional conditions and full induction was observed only in nitrogen-free medium. The predicted product of the Pi gene contains a region of homology with the homeobox sequence, suggesting that this gene encodes a DNA binding protein that directly regulates the expression of other genes.

  14. Cryptococcosis Serotypes Impact Outcome and Provide Evidence of Cryptococcus neoformans Speciation.

    PubMed

    Desnos-Ollivier, Marie; Patel, Sweta; Raoux-Barbot, Dorothée; Heitman, Joseph; Dromer, Françoise

    2015-06-09

    Cryptococcus neoformans is a human opportunistic fungal pathogen causing severe disseminated meningoencephalitis, mostly in patients with cellular immune defects. This species is divided into three serotypes: A, D, and the AD hybrid. Our objectives were to compare population structures of serotype A and D clinical isolates and to assess whether infections with AD hybrids differ from infections with the other serotypes. For this purpose, we analyzed 483 isolates and the corresponding clinical data from 234 patients enrolled during the CryptoA/D study or the nationwide survey on cryptococcosis in France. Isolates were characterized in terms of ploidy, serotype, mating type, and genotype, utilizing flow cytometry, serotype- and mating type-specific PCR amplifications, and multilocus sequence typing (MLST) methods. Our results suggest that C. neoformans serotypes A and D have different routes of multiplication (primarily clonal expansion versus recombination events for serotype A and serotype D, respectively) and important genomic differences. Cryptococcosis includes a high proportion of proven or probable infections (21.5%) due to a mixture of genotypes, serotypes, and/or ploidies. Multivariate analysis showed that parameters independently associated with failure to achieve cerebrospinal fluid (CSF) sterilization by week 2 were a high serum antigen titer, the lack of flucytosine during induction therapy, and the occurrence of mixed infection, while infections caused by AD hybrids were more likely to be associated with CSF sterilization. Our study provides additional evidence for the possible speciation of C. neoformans var. neoformans and grubii and highlights the importance of careful characterization of causative isolates. Cryptococcus neoformans is an environmental fungus causing severe disease, estimated to be responsible for 600,000 deaths per year worldwide. This species is divided into serotypes A and D and an AD hybrid, and these could be considered two

  15. Serotyping of primary human immunodeficiency virus type 1 isolates from diverse geographic locations by flow cytometry.

    PubMed Central

    Zolla-Pazner, S; O'Leary, J; Burda, S; Gorny, M K; Kim, M; Mascola, J; McCutchan, F

    1995-01-01

    The immunologic relatedness of the various human immunodeficiency virus type 1 (HIV-1) clades was determined with 13 human anti-HIV-1 monoclonal antibodies (MAbs) to six immunogenic regions of the HIV-1 structural proteins. The immunoreactivity of the native, oligomeric viral envelope glycoproteins expressed on the surfaces of human peripheral blood mononuclear cells infected in vitro with primary isolates from clades A through E was determined by flow cytometry. Some epitopes in the immunodominant region of gp41 and the C terminus of gp120 appear to be HIV-1 group specific in that they are expressed on the surfaces of cells in cultures infected with the majority of viruses tested from clades A to E. Epitopes within the V3 region appear to be clade restricted. Surprisingly, one MAb to an epitope in the C terminus of gp120 was entirely clade B specific. Staining with anti-V2 and anti-CD4 binding domain (CD4bd) reagents was infrequently detected. Anti-CD4bd MAbs stained only CD4-negative T cells because the CD4bd of gp120 appeared to be complexed with membrane CD4. When present, the epitopes of V2 and the CD4bd appeared to be expressed on cells infected with various clades. Thus, the results suggest that MAbs to gp41, the C terminus, and the V3 loop of gp120 are most useful in serotyping primary isolates of HIV-1, providing group-specific, clade-restricted, and clade-specific reagents. The use of the immunofluorescent method with the reagents described herein distinguishes infection with clade B from that with all other HIV-1 clades. With additional MAbs, this technique will allow a broadly applicable, reproducible, and practical method for serotyping HIV-1. PMID:7745728

  16. Molecular Polymorphism in the MTA and MTB Mating Type Genes of Tetrahymena thermophila and Related Asexual Species.

    PubMed

    Booth, Laurie; Wolfe, Benjamin; Doerder, F Paul

    2015-01-01

    Each of the seven mating types of Tetrahymena thermophila is determined by a pair of large genes, MTA and MTB, whose expression peaks at early conjugation. Each protein consists of a mating-type specific domain and a common transmembrane domain. To assess variation in natural populations, regions of both domains from wild isolates expressing mating types V and VII were analyzed. Corresponding regions of amicronucleates incapable of mating also were examined. MTA and MTB showed high haplotype diversity, with greater sequence variation in MTB. Mating type VII was less variable than mating type V, suggesting more recent origin. No polymorphism distinguished between mat1- and mat2-like alleles encoding different arrays of mating types, nor did polymorphisms give evidence of population structure. MTA and MTB variants have different phylogenies, suggesting independent rather than concerted evolution, and are under weak purifying selection. Codon usage is less biased than for housekeeping genes, and reassigned glutamine encoding stop codons are preferentially used. Amicronucleate T. thermophila and closely related nsp15 and nsp25 have higher levels of nucleotide and amino acid substitution, consistent with cox1 distances. The results suggest that complete sequencing of mating type genes of wild isolates coupled with functional analysis will be informative. © 2015 The Author(s) Journal of Eukaryotic Microbiology © 2015 International Society of Protistologists.

  17. HIV type 1 V3 serotyping of Tanzanian samples: probable reasons for mismatching with genetic subtyping.

    PubMed

    Hoelscher, M; Hanker, S; Barin, F; Cheingsong-Popov, R; Dietrich, U; Jordan-Harder, B; Olaleye, D; Nägele, E; Markuzzi, A; Mwakagile, D; Minja, F; Weber, J; Gürtler, L; Von Sonnenburg, F

    1998-01-20

    HIV-1 V3 serotyping is used to classify immunodeficiency viruses on the basis of antibody binding to V3 peptides derived from env genetic subtypes. Although it shows a reasonable overlap, it has been reported to be distinct from viral genetic subtypes. The aim of this study is to determine the feasibility of HIV-1 serotyping to predict genetic subtypes in an East African setting, where multiple HIV-1 subtypes have coexisted for many years. HIV-1 genetic subtypes of 86 AIDS patients in Mbeya Town, southwest Tanzania, were determined, using env nucleic acid sequencing as the basis for comparison. Those data were compared with V3 serotyping results obtained by four different methodologies. Four HIV-1 genetic subtypes were identified, including A (25, 29%), C (47, 55%), D (13, 15%), and G (1, 1%). The sensitivity and specificity of those serotyping assays varied considerably: sensitivity for genetic subtype A (40-48%), C (52-96%), and D (9-31%); and specificity for genetic subtype A (77-95%), C (46-63%), and D (97-100%). We further tried to identify reasons for the discrepancies between serotyping results and genetic subtypes. By means of logistic regression analysis three amino acid residues within the V3 loop (positions 12, 13, and 19; V, H, and A for serotype A, I, R, and T for serotype C) were found to be most important for antibody binding; a deviation from the subtype-specific amino acids was highly related to mismatched results. In addition, we have shown that phenetic analysis of V3 amino acid sequence data could be used to predict the majority of V3 serotypes (93-94%). Our data demonstrated that for the majority of specimens HIV-1 V3 serotyping results closely match the subtype of the analyzed sample as revealed by the V3 loop amino acid sequence. However, our data demonstrate that HIV-1 serotyping is not sufficiently accurate to predict genetic subtypes in Tanzania, where subtypes A, C, D, and G are circulating. This was due to highly similar amino acid

  18. Advances in Understanding Mating Type Gene Organization in the Mushroom-Forming Fungus Flammulina velutipes

    PubMed Central

    Wang, Wei; Lian, Lingdan; Xu, Ping; Chou, Tiansheng; Mukhtar, Irum; Osakina, Aron; Waqas, Muhammad; Chen, Bingzhi; Liu, Xinrui; Liu, Fang; Xie, Baogui; van Peer, Arend F.

    2016-01-01

    The initiation of sexual development in the important edible and medicinal mushroom Flammulina velutipes is controlled by special genes at two different, independent, mating type (MAT) loci: HD and PR. We expanded our understanding of the F. velutipes mating type system by analyzing the MAT loci from a series of strains. The HD locus of F. velutipes houses homeodomain genes (Hd genes) on two separated locations: sublocus HD-a and HD-b. The HD-b subloci contained strain-specific Hd1/Hd2 gene pairs, and crosses between strains with different HD-b subloci indicated a role in mating. The function of the HD-a sublocus remained undecided. Many, but not all strains contained the same conserved Hd2 gene at the HD-a sublocus. The HD locus usually segregated as a whole, though we did detect one new HD locus with a HD-a sublocus from one parental strain, and a HD-b sublocus from the other. The PR locus of F. velutipes contained pheromone receptor (STE3) and pheromone precursor (Pp) genes at two locations, sublocus PR-a and PR-b. PR-a and PR-b both contained sets of strain-specific STE3 and Pp genes, indicating a role in mating. PR-a and PR-b cosegregated in our experiments. However, the identification of additional strains with identical PR-a, yet different PR-b subloci, demonstrated that PR subloci can recombine within the PR locus. In conclusion, at least three of the four MAT subloci seem to participate in mating, and new HD and PR loci can be generated through intralocus recombination in F. velutipes. PMID:27621376

  19. Variation in Salmonella resistance to poultry chemical decontaminants, based on serotype, phage type, and antibiotic resistance patterns.

    PubMed

    Capita, Rosa

    2007-08-01

    Chemical decontaminants are currently under review for final approval by the European Union authorities with the aim of reducing the number and/or prevalence of pathogenic microorganisms on poultry. The purpose of the research being reported here was to determine the association, if any, of decontaminant resistance with the serotype, phage type, and antibiotic resistance of Salmonella strains. Sixty poultry isolates of Salmonella enterica (serotypes Enteritidis: phage types 1, 4, 4b, 6a, 14b, and 35; Typhimurium; Newport; Infantis; Poona; Virchow; Agona; Derby; and Paratyphi B) showing resistance to none (sensitive), one (resistant), two, three, four, five, six, seven, or nine (multiresistant) antibiotics were screened for resistance to 1,000 ppm acidified sodium chlorite, 1.2% trisodium phosphate, or 25% citric acid. D-values (seconds required for 1-log reduction in the number of bacteria) in peptone water, using a linear regression, of Salmonella in the presence of acidified sodium chlorite varied widely with serotype (the highest resistance levels were shown by serotypes Typhimurium, Newport, and Derby) and antibiotic resistance pattern (average values of 8.37 +/- 1.69 s for multiresistant strains as compared with 5.96 +/- 0.54 s for sensitive, P < 0.05). A positive relationship (0.775, P < 0.001) was found between acidified sodium chlorite D-values and the number of antibiotics to which strains were resistant. Both serotype and antibiotic resistance had only a slight influence over Salmonella resistance to trisodium phosphate, with average D-values from 12.44 +/- 0.91 s (sensitive strains) to 13.28 +/- 0.77 s (multiresistant) (P < 0.05). Neither serotype nor antibiotic profile was associated with Salmonella resistance to citric acid (average D-value of 12.20 +/- 0.81 s). Minimal differences in resistance to decontaminants were found among Salmonella Enteritidis phage types. Results in the present study highlight the importance of selecting an adequate strain

  20. Comparative analysis of the mating-type loci from Neurospora crassa and Sordaria macrospora: identification of novel transcribed ORFs.

    PubMed

    Pöggeler, S; Kück, U

    2000-03-01

    The mating-type locus controls mating and sexual development in filamentous ascomycetes. In the heterothallic ascomycete Neurospora crassa, the genes that confer mating behavior comprise dissimilar DNA sequences (idiomorphs) in the mat a and mat A mating partners. In the homothallic fungus Sordaria macrospora, sequences corresponding to both idiomorphs are located contiguously in the mating-type locus, which contains one chimeric gene, Smt A-3, that includes sequences which are similar to sequences found at the mat A and mat a mating-type idiomorphs in N. crassa. In this study, we describe the comparative transcriptional analysis of the chimeric mating-type region of S. macrospora and the corresponding region of the N. crassa mat a idiomorph. By means of RT-PCR experiments, we identified novel intervening sequences in the mating-type loci of both ascomycetes and, hence, concluded that an additional ORF, encoding a putative polypeptide of 79 amino acids, is present in the N. crassa mat a idiomorph. Furthermore, our analysis revealed co-transcription of the novel gene with the mat a-1 gene in N. crassa. The same mode of transcription was found in the corresponding mating-type region of S. macrospora, where the chimeric Smt A-3 gene is co-transcribed with the mat a-specific Smt a-1 gene. Analysis of a Smt A-3 cDNA revealed optional splicing of two introns. We believe that this is the first report of co-transcription of protein-encoding nuclear genes in filamentous fungi. Possible functions of the novel ORFs in regulating mating-type gene expression are discussed.

  1. Relationship between Monokaryotic Growth Rate and Mating Type in the Edible Basidiomycete Pleurotus ostreatus

    PubMed Central

    Larraya, Luis M.; Pérez, Gúmer; Iribarren, Iñaki; Blanco, Juan A.; Alfonso, Mikel; Pisabarro, Antonio G.; Ramírez, Lucía

    2001-01-01

    The edible fungus Pleurotus ostreatus (oyster mushroom) is an industrially produced heterothallic homobasidiomycete whose mating is controlled by a bifactorial tetrapolar genetic system. Two mating loci (matA and matB) control different steps of hyphal fusion, nuclear migration, and nuclear sorting during the onset and progress of the dikaryotic growth. Previous studies have shown that the segregation of the alleles present at the matB locus differs from that expected for a single locus because (i) new nonparental B alleles appeared in the progeny and (ii) there was a distortion in the segregation of the genomic regions close to this mating locus. In this study, we pursued these observations by using a genetic approach based on the identification of molecular markers linked to the matB locus that allowed us to dissect it into two genetically linked subunits (matBα and matBβ) and to correlate the presence of specific matBα and matA alleles with differences in monokaryotic growth rate. The availability of these molecular markers and the mating type dependence of growth rate in monokaryons can be helpful for marker-assisted selection of fast-growing monokaryons to be used in the construction of dikaryons able to colonize the substrate faster than the competitors responsible for reductions in the industrial yield of this fungus. PMID:11472908

  2. Whole Genome Sequencing of 39 Invasive Streptococcus pneumoniae Sequence Type 199 Isolates Revealed Switches from Serotype 19A to 15B.

    PubMed

    Makarewicz, Oliwia; Lucas, Marie; Brandt, Christian; Herrmann, Leonie; Albersmeier, Andreas; Rückert, Christian; Blom, Jochen; Goesmann, Alexander; van der Linden, Mark; Kalinowski, Jörn; Pletz, Mathias W

    2017-01-01

    Streptococcus pneumoniae is a major pathogen that causes different invasive pneumococcal diseases (IPD). The pneumococcal polysaccharide capsule is a main virulence factor. More than 94 capsule types have been described, but only a limited number of capsule types accounted for the majority of IPD cases before the introduction of pneumococcal vaccines. After the introduction of the conjugated pneumococcal vaccine PCV7, which covered the seven most frequent serotypes in IPD in the USA, an increase in IPD caused by non-vaccine serotypes was observed, and serotype 19A, which belongs to sequence type (ST) 199, was among the most prevalent STs. After the introduction of the extended vaccine PCV13, which includes serotype 19A, serogroup 15B/C increased in IPD. Therefore, whole genome sequences of 39 isolates of ST199 from Germany (collected between 1998 and 2011) with serotype 19A (n = 24) and serogroup 15B/C (n = 15) were obtained using an Illumina platform and were analysed to identify capsular switches within ST199. Two 19A to 15B/C serotype switch events were identified. Both events occurred before the introduction of PCV7, which indicates that a capsular switch from 19A to 15B among ST199 isolates is not unusual and is not directly linked to the vaccination. The observed serotype replacement appears to be the result of a vacant niche due to the displacement of vaccine serotypes that is now successfully occupied by ST199 clones.

  3. Whole Genome Sequencing of 39 Invasive Streptococcus pneumoniae Sequence Type 199 Isolates Revealed Switches from Serotype 19A to 15B

    PubMed Central

    Lucas, Marie; Brandt, Christian; Herrmann, Leonie; Albersmeier, Andreas; Blom, Jochen; Goesmann, Alexander

    2017-01-01

    Streptococcus pneumoniae is a major pathogen that causes different invasive pneumococcal diseases (IPD). The pneumococcal polysaccharide capsule is a main virulence factor. More than 94 capsule types have been described, but only a limited number of capsule types accounted for the majority of IPD cases before the introduction of pneumococcal vaccines. After the introduction of the conjugated pneumococcal vaccine PCV7, which covered the seven most frequent serotypes in IPD in the USA, an increase in IPD caused by non-vaccine serotypes was observed, and serotype 19A, which belongs to sequence type (ST) 199, was among the most prevalent STs. After the introduction of the extended vaccine PCV13, which includes serotype 19A, serogroup 15B/C increased in IPD. Therefore, whole genome sequences of 39 isolates of ST199 from Germany (collected between 1998 and 2011) with serotype 19A (n = 24) and serogroup 15B/C (n = 15) were obtained using an Illumina platform and were analysed to identify capsular switches within ST199. Two 19A to 15B/C serotype switch events were identified. Both events occurred before the introduction of PCV7, which indicates that a capsular switch from 19A to 15B among ST199 isolates is not unusual and is not directly linked to the vaccination. The observed serotype replacement appears to be the result of a vacant niche due to the displacement of vaccine serotypes that is now successfully occupied by ST199 clones. PMID:28046133

  4. [Macronuclear DNA and total protein contents of mating types I and II of Paramecium primaurelia, during the phase of maturity and the transition to senescence. Preliminary observations].

    PubMed

    Delmonte Corrado, M U; Crippa Franceschi, T

    1992-01-01

    Concerning the studies on mating type differentiation and life cycle development in Paramecium primaurelia stock 90, both macronuclear DNA and total protein contents have been measured cytofluorometrically in mating type I and mating type II isogenic cell lines growing in logarithmic phase, throughout their maturity period and transition to senescence. The target was to investigate whether the two mating types undergo clonal decline in different times, as the previous studies suggested. The results indicate that, throughout the maturity period, macronuclear DNA and total protein contents vary both in mating type I and mating type II cell lines; moreover, aged phenotypes as the dramatic decrease of both contents, firstly occur in mating type II which, therefore, appears to be submitted to clonal decline before mating type I.

  5. Genome-defence small RNAs exapted for epigenetic mating-type inheritance.

    PubMed

    Singh, Deepankar Pratap; Saudemont, Baptiste; Guglielmi, Gérard; Arnaiz, Olivier; Goût, Jean-François; Prajer, Malgorzata; Potekhin, Alexey; Przybòs, Ewa; Aubusson-Fleury, Anne; Bhullar, Simran; Bouhouche, Khaled; Lhuillier-Akakpo, Maoussi; Tanty, Véronique; Blugeon, Corinne; Alberti, Adriana; Labadie, Karine; Aury, Jean-Marc; Sperling, Linda; Duharcourt, Sandra; Meyer, Eric

    2014-05-22

    In the ciliate Paramecium, transposable elements and their single-copy remnants are deleted during the development of somatic macronuclei from germline micronuclei, at each sexual generation. Deletions are targeted by scnRNAs, small RNAs produced from the germ line during meiosis that first scan the maternal macronuclear genome to identify missing sequences, and then allow the zygotic macronucleus to reproduce the same deletions. Here we show that this process accounts for the maternal inheritance of mating types in Paramecium tetraurelia, a long-standing problem in epigenetics. Mating type E depends on expression of the transmembrane protein mtA, and the default type O is determined during development by scnRNA-dependent excision of the mtA promoter. In the sibling species Paramecium septaurelia, mating type O is determined by coding-sequence deletions in a different gene, mtB, which is specifically required for mtA expression. These independently evolved mechanisms suggest frequent exaptation of the scnRNA pathway to regulate cellular genes and mediate transgenerational epigenetic inheritance of essential phenotypic polymorphisms.

  6. The genetic instabilities of the mating type locus in fission yeast.

    PubMed

    Egel, R

    1976-06-15

    Certain genetic instabilities of the "mating type locus" in the yeast Schizosaccharomyces pombe are interpreted in terms of transposition: Homothallic strains are characterized by two adjacent mating type genes (mat1-mat2+) with sexually complementary functions. One of these genes (mat2+) is able to duplicate itself, and the duplicated copy maps at the position of mat1-. The former function of mat1-is lost (owing to insertion), and only becomes reactivated when the inserted sequence (mat1+) is again excised. Analyses of analogous instabilities expressed by the partially defective mutation mat2+ -B102 have substantiated this transposition scheme. Homothallism is acribed to alternate and mutually exclusive activation of mat1- or mat2+ genes.

  7. Comparison of proteome typing and serotyping of Streptococcus parauberis isolates from olive flounder (Paralichthys olivaceus).

    PubMed

    Kim, Si Won; Jang, Ho Bin; Lee, Jung Seok; Im, Se Pyeong; Lazarte, Jassy Mary S; Seo, Jong Pyo; Lee, Woo Jai; Kim, Jae Sung; Jung, Tae Sung

    2015-11-01

    The olive flounder (Paralichthys olivaceus) is a cultivated marine species that is economically important in Korea and Japan. Several bacterial pathogens have caused severe mortalities in farmed olive flounder, especially Streptococcus parauberis. We collected 145 S. parauberis isolates from diseased olive flounders from 2003 to 2008 in Jeju Island, South Korea and characterized them by Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI TOF MS) and by serology. The serological analysis divided the isolates into serotype I (62.1%) and serotype II (36.6%) and the proteome analysis divided the isolates into cluster 1 (43.4%) and cluster 2 (56.6%). All cluster 1 isolates had serotype I, but cluster 2 consisted of serotype I (32.9%), serotype II (64.6%), and others (2.5%). Further detailed analysis of the mass spectra led to identification of several specific m/z peaks that enabled discrimination between cluster 1 and 2 and between serotype I and II within cluster 2. Our results suggest that MALDI TOF MS analysis has potential as an alternative method for the rapid and reliable identification of the fish pathogen S. parauberis.

  8. Transcription of two long noncoding RNAs mediates mating-type control of gametogenesis in budding yeast.

    PubMed

    van Werven, Folkert J; Neuert, Gregor; Hendrick, Natalie; Lardenois, Aurélie; Buratowski, Stephen; van Oudenaarden, Alexander; Primig, Michael; Amon, Angelika

    2012-09-14

    The cell-fate decision leading to gametogenesis is essential for sexual reproduction. In S. cerevisiae, only diploid MATa/α but not haploid MATa or MATα cells undergo gametogenesis, known as sporulation. We find that transcription of two long noncoding RNAs (lncRNAs) mediates mating-type control of sporulation. In MATa or MATα haploids, expression of IME1, the central inducer of gametogenesis, is inhibited in cis by transcription of the lncRNA IRT1, located in the IME1 promoter. IRT1 transcription recruits the Set2 histone methyltransferase and the Set3 histone deacetylase complex to establish repressive chromatin at the IME1 promoter. Inhibiting expression of IRT1 and an antisense transcript that antagonizes the expression of the meiotic regulator IME4 allows cells expressing the haploid mating type to sporulate with kinetics that are indistinguishable from that of MATa/α diploids. Conversely, expression of the two lncRNAs abolishes sporulation in MATa/α diploids. Thus, transcription of two lncRNAs governs mating-type control of gametogenesis in yeast.

  9. Functional convergence and divergence of mating-type genes fulfilling in Cordyceps militaris.

    PubMed

    Lu, Yuzhen; Xia, Yongliang; Luo, Feifei; Dong, Caihong; Wang, Chengshu

    2016-03-01

    Fungal sexual lives are considerably diversified in terms of the types of mating systems and mating-control gene functions. Sexual fruiting bodies of the ascomycete fungus Cordyceps militaris have been widely consumed as edible and medicinal mushrooms, whereas the regulation of fruiting-body development and sex in this fungus remain elusive. Herein, we performed the comprehensive functional analyses of mating-type (MAT) genes in C. militaris. Interspecies functional convergence was evident that MAT1-1 and MAT1-2-1 null mutants were sterile and lost the ability to produce stromata in outcrosses with the opposite mating-type partner. In contrast to other fungal species, functional divergence of MAT1-1-1 and MAT1-1-2 was also observed that ΔMAT1-1-1 produced barren stromata in outcrosses, whereas ΔMAT1-1-2 generated fruiting bodies morphologically similar to that of the parental strain but with sterile perithecia. The homothallic-like transformants MAT1-2::MAT1-1-1 (haploidic MAT1-2 isolate transformed with the MAT1-1-1 gene) produced sterile stromata, whereas the MAT1-1::MAT1-2-1 (haploidic MAT1-1 isolate transformed with the MAT1-2-1 gene) mutant was determined to be completely fruitless. The findings relating to the fully fertile gene-complementation mutants suggest that the genomic location is not essential for the MAT genes to fulfill their functions in C. militaris. Comparison of the production of bioactive constituents cordycepin and adenosine provides experimental support that the fungal sexual cycle is an energy consuming process. The results of the present study enrich our knowledge of both convergent and divergent controls of fungal sex.

  10. Asexual cephalosporin C producer Acremonium chrysogenum carries a functional mating type locus.

    PubMed

    Pöggeler, Stefanie; Hoff, Birgit; Kück, Ulrich

    2008-10-01

    Acremonium chrysogenum, the fungal producer of the pharmaceutically relevant beta-lactam antibiotic cephalosporin C, is classified as asexual because no direct observation of mating or meiosis has yet been reported. To assess the potential of A. chrysogenum for sexual reproduction, we screened an expressed sequence tag library from A. chrysogenum for the expression of mating type (MAT) genes, which are the key regulators of sexual reproduction. We identified two putative mating type genes that are homologues of the alpha-box domain gene, MAT1-1-1 and MAT1-1-2, encoding an HPG domain protein defined by the presence of the three invariant amino acids histidine, proline, and glycine. In addition, cDNAs encoding a putative pheromone receptor and pheromone-processing enzymes, as well as components of a pheromone response pathway, were found. Moreover, the entire A. chrysogenum MAT1-1 (AcMAT1-1) gene and regions flanking the MAT region were obtained from a genomic cosmid library, and sequence analysis revealed that in addition to AcMAT1-1-1 and AcMAT1-1-2, the AcMAT1-1 locus comprises a third mating type gene, AcMAT1-1-3, encoding a high-mobility-group domain protein. The alpha-box domain sequence of AcMAT1-1-1 was used to determine the phylogenetic relationships of A. chrysogenum to other ascomycetes. To determine the functionality of the AcMAT1-1 locus, the entire MAT locus was transferred into a MAT deletion strain of the heterothallic ascomycete Podospora anserina (the PaDeltaMAT strain). After fertilization with a P. anserina MAT1-2 (MAT(+)) strain, the corresponding transformants developed fruiting bodies with mature ascospores. Thus, the results of our functional analysis of the AcMAT1-1 locus provide strong evidence to hypothesize a sexual cycle in A. chrysogenum.

  11. Mating type loci of Sporisorium reilianum: novel pattern with three a and multiple b specificities.

    PubMed

    Schirawski, Jan; Heinze, Bernadette; Wagenknecht, Martin; Kahmann, Regine

    2005-08-01

    Sporisorium reilianum and Ustilago maydis are two closely related smut fungi, which both infect maize but differ fundamentally in their mode of plant invasion and site of symptom development. As a prelude to studying the molecular basis of these differences, we have characterized the mating type loci of S. reilianum. S. reilianum has two unlinked mating type loci, a and b. Genes in both loci and adjacent regions show a high degree of synteny to the corresponding genes of U. maydis. The b locus occurs in at least five alleles and encodes two subunits of a heterodimeric homeodomain transcription factor, while the a locus encodes a pheromone/receptor system. However, in contrast to that of U. maydis, the a locus of S. reilianum exists in three alleles containing two active pheromone genes each. The alleles of the a locus appear to have arisen through recent recombination events within the locus itself. This has created a situation where each pheromone is specific for recognition by only one mating partner.

  12. Mating Type Loci of Sporisorium reilianum: Novel Pattern with Three a and Multiple b Specificities

    PubMed Central

    Schirawski, Jan; Heinze, Bernadette; Wagenknecht, Martin; Kahmann, Regine

    2005-01-01

    Sporisorium reilianum and Ustilago maydis are two closely related smut fungi, which both infect maize but differ fundamentally in their mode of plant invasion and site of symptom development. As a prelude to studying the molecular basis of these differences, we have characterized the mating type loci of S. reilianum. S. reilianum has two unlinked mating type loci, a and b. Genes in both loci and adjacent regions show a high degree of synteny to the corresponding genes of U. maydis. The b locus occurs in at least five alleles and encodes two subunits of a heterodimeric homeodomain transcription factor, while the a locus encodes a pheromone/receptor system. However, in contrast to that of U. maydis, the a locus of S. reilianum exists in three alleles containing two active pheromone genes each. The alleles of the a locus appear to have arisen through recent recombination events within the locus itself. This has created a situation where each pheromone is specific for recognition by only one mating partner. PMID:16087737

  13. Cryptococcosis Serotypes Impact Outcome and Provide Evidence of Cryptococcus neoformans Speciation

    PubMed Central

    Desnos-Ollivier, Marie; Patel, Sweta; Raoux-Barbot, Dorothée; Heitman, Joseph

    2015-01-01

    ABSTRACT Cryptococcus neoformans is a human opportunistic fungal pathogen causing severe disseminated meningoencephalitis, mostly in patients with cellular immune defects. This species is divided into three serotypes: A, D, and the AD hybrid. Our objectives were to compare population structures of serotype A and D clinical isolates and to assess whether infections with AD hybrids differ from infections with the other serotypes. For this purpose, we analyzed 483 isolates and the corresponding clinical data from 234 patients enrolled during the CryptoA/D study or the nationwide survey on cryptococcosis in France. Isolates were characterized in terms of ploidy, serotype, mating type, and genotype, utilizing flow cytometry, serotype- and mating type-specific PCR amplifications, and multilocus sequence typing (MLST) methods. Our results suggest that C. neoformans serotypes A and D have different routes of multiplication (primarily clonal expansion versus recombination events for serotype A and serotype D, respectively) and important genomic differences. Cryptococcosis includes a high proportion of proven or probable infections (21.5%) due to a mixture of genotypes, serotypes, and/or ploidies. Multivariate analysis showed that parameters independently associated with failure to achieve cerebrospinal fluid (CSF) sterilization by week 2 were a high serum antigen titer, the lack of flucytosine during induction therapy, and the occurrence of mixed infection, while infections caused by AD hybrids were more likely to be associated with CSF sterilization. Our study provides additional evidence for the possible speciation of C. neoformans var. neoformans and grubii and highlights the importance of careful characterization of causative isolates. PMID:26060271

  14. Chromosomal Rearrangements in Salmonella enterica Serotype Typhi Affecting Molecular Typing in Outbreak Investigations

    PubMed Central

    Echeita, M. A.; Usera, M. A.

    1998-01-01

    Salmonella enterica serotype Typhi strains belonging to eight different outbreaks of typhoid fever that occurred in Spain between 1989 and 1994 were analyzed by ribotyping and pulsed-field gel electrophoresis. For three outbreaks, two different patterns were detected for each outbreak. The partial digestion analysis by the intron-encoded endonuclease I-CeuI of the two different strains from each outbreak provided an excellent tool for examining the organization of the genomes of epidemiologically related strains. S. enterica serotype Typhi seems to be more susceptible than other serotypes to genetic rearrangements produced by homologous recombinations between rrn operons; these rearrangements do not substantially alter the stability or survival of the bacterium. We conclude that genetic rearrangements can occur during the emergence of an outbreak. PMID:9650981

  15. Virulence Studies of Different Sequence Types and Geographical Origins of Streptococcus suis Serotype 2 in a Mouse Model of Infection

    PubMed Central

    Auger, Jean-Philippe; Fittipaldi, Nahuel; Benoit-Biancamano, Marie-Odile; Segura, Mariela; Gottschalk, Marcelo

    2016-01-01

    Multilocus sequence typing previously identified three predominant sequence types (STs) of Streptococcus suis serotype 2: ST1 strains predominate in Eurasia while North American (NA) strains are generally ST25 and ST28. However, ST25/ST28 and ST1 strains have also been isolated in Asia and NA, respectively. Using a well-standardized mouse model of infection, the virulence of strains belonging to different STs and different geographical origins was evaluated. Results demonstrated that although a certain tendency may be observed, S. suis serotype 2 virulence is difficult to predict based on ST and geographical origin alone; strains belonging to the same ST presented important differences of virulence and did not always correlate with origin. The only exception appears to be NA ST28 strains, which were generally less virulent in both systemic and central nervous system (CNS) infection models. Persistent and high levels of bacteremia accompanied by elevated CNS inflammation are required to cause meningitis. Although widely used, in vitro tests such as phagocytosis and killing assays require further standardization in order to be used as predictive tests for evaluating virulence of strains. The use of strains other than archetypal strains has increased our knowledge and understanding of the S. suis serotype 2 population dynamics. PMID:27409640

  16. Altered Mating-Type Identity in the Fungus Podospora Anserina Leads to Selfish Nuclei, Uniparental Progeny, and Haploid Meiosis

    PubMed Central

    Zickler, D.; Arnaise, S.; Coppin, E.; Debuchy, R.; Picard, M.

    1995-01-01

    In wild-type crosses of the filamentous ascomycete Podospora anserina, after fertilization, only nuclei of opposite mating type can form dikaryons that undergo karyogamy and meiosis, producing biparental progeny. To determine the role played by the mating type in these steps, the four mat genes were mutagenized in vitro and introduced into a strain deleted for its mat locus. Genetic and cytological analyses of these mutant strains, crossed to each other and to wild type, showed that mating-type information is required for recognition of nuclear identity during the early steps of sexual reproduction. In crosses with strains carrying a mating-type mutation, two unusual developmental patterns were observed: monokaryotic cells, resulting in haploid meiosis, and uniparental dikaryotic cells providing, after karyogamy and meiosis, a uniparental progeny. Altered mating-type identity leads to selfish behavior of the mutant nucleus: it migrates alone or paired, ignoring its wild-type partner in all mutant X wild-type crosses. This behavior is nucleus-autonomous because, in the same cytoplasm, the wild-type nuclei form only biparental dikaryons. In P. anserina, mat genes are thus required to ensure a biparental dikaryotic state but appear dispensable for later stages, such as meiosis and sporulation. PMID:7498731

  17. Schizosaccharomyces pombe switches mating type by the synthesis-dependent strand-annealing mechanism.

    PubMed

    Yamada-Inagawa, Tomoko; Klar, Amar J S; Dalgaard, Jacob Z

    2007-09-01

    Schizosaccharomyces pombe cells can switch between two mating types, plus (P) and minus (M). The change in cell type occurs due to a replication-coupled recombination event that transfers genetic information from one of the silent-donor loci, mat2P or mat3M, into the expressed mating-type determining mat1 locus. The mat1 locus can as a consequence contain DNA encoding either P or M information. A molecular mechanism, known as synthesis-dependent strand annealing, has been proposed for the underlying recombination event. A key feature of this model is that only one DNA strand of the donor locus provides the information that is copied into the mat1. Here we test the model by constructing strains that switch using two different mutant P cassettes introduced at the donor loci, mat2 and mat3. We show that in such strains wild-type P-cassette DNA is efficiently generated at mat1 through heteroduplex DNA formation and repair. The present data provide an in vivo genetic test of the proposed molecular recombination mechanism.

  18. Schizosaccharomyces pombe Switches Mating Type by the Synthesis-Dependent Strand-Annealing Mechanism

    PubMed Central

    Yamada-Inagawa, Tomoko; Klar, Amar J. S.; Dalgaard, Jacob Z.

    2007-01-01

    Schizosaccharomyces pombe cells can switch between two mating types, plus (P) and minus (M). The change in cell type occurs due to a replication-coupled recombination event that transfers genetic information from one of the silent-donor loci, mat2P or mat3M, into the expressed mating-type determining mat1 locus. The mat1 locus can as a consequence contain DNA encoding either P or M information. A molecular mechanism, known as synthesis-dependent strand annealing, has been proposed for the underlying recombination event. A key feature of this model is that only one DNA strand of the donor locus provides the information that is copied into the mat1. Here we test the model by constructing strains that switch using two different mutant P cassettes introduced at the donor loci, mat2 and mat3. We show that in such strains wild-type P-cassette DNA is efficiently generated at mat1 through heteroduplex DNA formation and repair. The present data provide an in vivo genetic test of the proposed molecular recombination mechanism. PMID:17660548

  19. Chromosome-refolding model of mating-type switching in yeast.

    PubMed

    Avşaroğlu, Barış; Bronk, Gabriel; Li, Kevin; Haber, James E; Kondev, Jane

    2016-10-24

    Chromosomes are folded into cells in a nonrandom fashion, with particular genetic loci occupying distinct spatial regions. This observation raises the question of whether the spatial organization of a chromosome governs its functions, such as recombination or transcription. We consider this general question in the specific context of mating-type switching in budding yeast, which is a model system for homologous recombination. Mating-type switching is induced by a DNA double-strand break (DSB) at the MAT locus on chromosome III, followed by homologous recombination between the cut MAT locus and one of two donor loci (HMLα and HMRa), located on the same chromosome. Previous studies have suggested that in MATa cells after the DSB is induced chromosome III undergoes refolding, which directs the MAT locus to recombine with HMLα. Here, we propose a quantitative model of mating-type switching predicated on the assumption of DSB-induced chromosome refolding, which also takes into account the previously measured stochastic dynamics and polymer nature of yeast chromosomes. Using quantitative fluorescence microscopy, we measure changes in the distance between the donor (HMLα) and MAT loci after the DSB and find agreement with the theory. Predictions of the theory also agree with measurements of changes in the use of HMLα as the donor, when we perturb the refolding of chromosome III. These results establish refolding of yeast chromosome III as a key driving force in MAT switching and provide an example of a cell regulating the spatial organization of its chromosome so as to direct homology search during recombination.

  20. Evolutionary erosion of yeast sex chromosomes by mating-type switching accidents

    PubMed Central

    Gordon, Jonathan L.; Armisén, David; Proux-Wéra, Estelle; ÓhÉigeartaigh, Seán S.; Byrne, Kevin P.; Wolfe, Kenneth H.

    2011-01-01

    We investigate yeast sex chromosome evolution by comparing genome sequences from 16 species in the family Saccharomycetaceae, including data from genera Tetrapisispora, Kazachstania, Naumovozyma, and Torulaspora. We show that although most yeast species contain a mating-type (MAT) locus and silent HML and HMR loci structurally analogous to those of Saccharomyces cerevisiae, their detailed organization is highly variable and indicates that the MAT locus is a deletion hotspot. Over evolutionary time, chromosomal genes located immediately beside MAT have continually been deleted, truncated, or transposed to other places in the genome in a process that is gradually shortening the distance between MAT and HML. Each time a gene beside MAT is removed by deletion or transposition, the next gene on the chromosome is brought into proximity with MAT and is in turn put at risk for removal. This process has also continually replaced the triplicated sequence regions, called Z and X, that allow HML and HMR to be used as templates for DNA repair at MAT during mating-type switching. We propose that the deletion and transposition events are caused by evolutionary accidents during mating-type switching, combined with natural selection to keep MAT and HML on the same chromosome. The rate of deletion accelerated greatly after whole-genome duplication, probably because genes were redundant and could be deleted without requiring transposition. We suggest that, despite its mutational cost, switching confers an evolutionary benefit by providing a way for an isolated germinating spore to reform spores if the environment is too poor. PMID:22123960

  1. Epidemiological Typing of Campylobacter Isolates from Meat Processing Plants by Pulsed-Field Gel Electrophoresis, Fatty Acid Profile Typing, Serotyping, and Biotyping

    PubMed Central

    Steele, M.; McNab, B.; Fruhner, L.; DeGrandis, S.; Woodward, D.; Odumeru, J. A.

    1998-01-01

    Campylobacter spp. are a leading cause of bacterial gastroenteritis. Foods of animal origin, particularly undercooked poultry, are common sources of Campylobacter species associated with disease in humans. A collection of 110 Campylobacter jejuni and 31 C. coli human and environmental isolates from different Ontario, Canada, abattoirs were analyzed by pulsed-field gel electrophoresis, fatty acid profile typing, and biotyping. Previously collected serotyping data for the same isolates were also analyzed in this study. Pulsed-field gel electrophoresis was found to be the most discriminatory of the typing methods, followed by serotyping, fatty acid profile typing, and biotyping. A wide variety of typing profiles were observed within the isolates, suggesting that several different Campylobacter sp. strains were present within the abattoirs. PMID:9647797

  2. Epidemiological typing of Campylobacter isolates from meat processing plants by pulsed-field gel electrophoresis, fatty acid profile typing, serotyping, and biotyping.

    PubMed

    Steele, M; McNab, B; Fruhner, L; DeGrandis, S; Woodward, D; Odumeru, J A

    1998-07-01

    Campylobacter spp. are a leading cause of bacterial gastroenteritis. Foods of animal origin, particularly under-cooked poultry, are common sources of Campylobacter species associated with disease in humans. A collection of 110 Campylobacter jejuni and 31 C. coli human and environmental isolates from different Ontario, Canada, abattoirs were analyzed by pulsed-field gel electrophoresis, fatty acid profile typing, and biotyping. Previously collected serotyping data for the same isolates were also analyzed in this study. Pulsed-field gel electrophoresis was found to be the most discriminatory of the typing methods, followed by serotyping, fatty acid profile typing, and biotyping. A wide variety of typing profiles were observed within the isolates, suggesting that several different Campylobacter sp. strains were present within the abattoirs.

  3. Capsular Polysaccharide (CPS) Release by Serotype 3 Pneumococcal Strains Reduces the Protective Effect of Anti-Type 3 CPS Antibodies

    PubMed Central

    Choi, Eun Hwa; Zhang, Fan; Lu, Ying-Jie

    2015-01-01

    The efficacy of the serotype 3 (ST3) pneumococcal conjugate vaccine (PCV) remains unclear. While the synthesis of capsular polysaccharide (CPS) of most serotypes is wzy dependent, the strains of two serotypes, 3 and 37, synthesize CPS by the synthase-dependent pathway, resulting in a polysaccharide that is not covalently linked to peptidoglycan and can be released during growth. We hypothesized that the release of CPS during growth reduces anti-type 3 CPS antibody-mediated protection and may explain the lower efficacy of the type 3 component of PCV than that of other PCVs. The in vitro-released CPS concentrations per 107 CFU of ST3 and ST37 strains were significantly higher than those for the ST1, ST4, ST6B, and ST14 strains. Following intraperitoneal (i.p.) injection in mice, blood concentrations of CPS were significantly higher for the ST3 than for the ST4/5 strains. The opsonophagocytic killing assay (OPKA) titer of anti-type 3 CPS antibody was significantly reduced by type 3 CPS, culture supernatant, or serum from Streptococcus pneumoniae ST3 strain WU2-infected mice. Mice were injected with capsule-specific antibodies and challenged i.p. with or without the addition of sterile culture supernatant containing type-specific CPS. The addition of 0.2 μl of culture supernatant from WU2 inhibited passive protection, whereas 100-fold-more culture supernatant from S. pneumoniae ST4 strain TIGR4 was required for the inhibition of protection. We conclude that released type 3 CPS interferes with antibody-mediated killing and protection by anti-CPS antibodies. The relative failure of ST3 PCV may be due to CPS release, suggesting that alternative immunization approaches for ST3 may be necessary. PMID:26677201

  4. Capsular Polysaccharide (CPS) Release by Serotype 3 Pneumococcal Strains Reduces the Protective Effect of Anti-Type 3 CPS Antibodies.

    PubMed

    Choi, Eun Hwa; Zhang, Fan; Lu, Ying-Jie; Malley, Richard

    2015-12-16

    The efficacy of the serotype 3 (ST3) pneumococcal conjugate vaccine (PCV) remains unclear. While the synthesis of capsular polysaccharide (CPS) of most serotypes is wzy dependent, the strains of two serotypes, 3 and 37, synthesize CPS by the synthase-dependent pathway, resulting in a polysaccharide that is not covalently linked to peptidoglycan and can be released during growth. We hypothesized that the release of CPS during growth reduces anti-type 3 CPS antibody-mediated protection and may explain the lower efficacy of the type 3 component of PCV than that of other PCVs. The in vitro-released CPS concentrations per 10(7) CFU of ST3 and ST37 strains were significantly higher than those for the ST1, ST4, ST6B, and ST14 strains. Following intraperitoneal (i.p.) injection in mice, blood concentrations of CPS were significantly higher for the ST3 than for the ST4/5 strains. The opsonophagocytic killing assay (OPKA) titer of anti-type 3 CPS antibody was significantly reduced by type 3 CPS, culture supernatant, or serum from Streptococcus pneumoniae ST3 strain WU2-infected mice. Mice were injected with capsule-specific antibodies and challenged i.p. with or without the addition of sterile culture supernatant containing type-specific CPS. The addition of 0.2 μl of culture supernatant from WU2 inhibited passive protection, whereas 100-fold-more culture supernatant from S. pneumoniae ST4 strain TIGR4 was required for the inhibition of protection. We conclude that released type 3 CPS interferes with antibody-mediated killing and protection by anti-CPS antibodies. The relative failure of ST3 PCV may be due to CPS release, suggesting that alternative immunization approaches for ST3 may be necessary.

  5. Complex Population Structure and Virulence Differences among Serotype 2 Streptococcus suis Strains Belonging to Sequence Type 28

    PubMed Central

    Athey, Taryn B. T.; Auger, Jean-Philippe; Teatero, Sarah; Dumesnil, Audrey; Takamatsu, Daisuke; Wasserscheid, Jessica; Dewar, Ken; Gottschalk, Marcelo; Fittipaldi, Nahuel

    2015-01-01

    Streptococcus suis is a major swine pathogen and a zoonotic agent. Serotype 2 strains are the most frequently associated with disease. However, not all serotype 2 lineages are considered virulent. Indeed, sequence type (ST) 28 serotype 2 S. suis strains have been described as a homogeneous group of low virulence. However, ST28 strains are often isolated from diseased swine in some countries, and at least four human ST28 cases have been reported. Here, we used whole-genome sequencing and animal infection models to test the hypothesis that the ST28 lineage comprises strains of different genetic backgrounds and different virulence. We used 50 S. suis ST28 strains isolated in Canada, the United States and Japan from diseased pigs, and one ST28 strain from a human case isolated in Thailand. We report a complex population structure among the 51 ST28 strains. Diversity resulted from variable gene content, recombination events and numerous genome-wide polymorphisms not attributable to recombination. Phylogenetic analysis using core genome single-nucleotide polymorphisms revealed four discrete clades with strong geographic structure, and a fifth clade formed by US, Thai and Japanese strains. When tested in experimental animal models, strains from this latter clade were significantly more virulent than a Canadian ST28 reference strain, and a closely related Canadian strain. Our results highlight the limitations of MLST for both phylogenetic analysis and virulence prediction and raise concerns about the possible emergence of ST28 strains in human clinical cases. PMID:26375680

  6. Mating compatibility and competitiveness of transgenic and wild type Aedes aegypti (L.) under contained semi-field conditions.

    PubMed

    Lee, H L; Vasan, Seshadri; Ahmad, Nazni Wasi; Idris, Iswarti; Hanum, Norhaida; Selvi, S; Alphey, Luke; Murad, Shahnaz

    2013-02-01

    We conducted the world's first experiments under semi-field conditions (ACL-2 field house) to assess the mating competitiveness of genetically sterile RIDL male mosquitoes (513A strain). The field house is a state-of-the-art, fully-contained trial facility, simulating the living space for a household of 2-4 people in Peninsular Malaysia. Ten genetically sterile RIDL male A. aegypti mosquitoes competed with ten wild type males inside this field house to mate with ten wild type females. Hatched larvae from mated females were screened under a fluorescent microscope for genetic markers to determine if they were fathered by RIDL male or wild type male, and all results were cross-checked by PCR. Two such experiments were conducted, each repeated sufficient number of times. All strains were on a Malaysian lab strain background for the first experiment, while the RIDL males alone were on a recently-colonised Mexican strain background for the second experiment. A total of 52 % of the matings were with RIDL males in the first experiment, while 45 % of the matings were with RIDL (Mexican) males in the second experiment. Statistically, this is not significantly different from 50 % of the matings expected to take place with RIDL males if the latter were as competitive as that of the wild type males. This shows that A. aegypti RIDL-513A has excellent mating competitiveness under semi-field conditions, verifying earlier trends obtained in small lab cages. We also observed high mating compatibility between recently-colonised Mexican RIDL males and lab-reared Malaysian wild type females.

  7. Comparative Genomics of the Mating-Type Loci of the Mushroom Flammulina velutipes Reveals Widespread Synteny and Recent Inversions

    PubMed Central

    van Peer, Arend F.; Park, Soon-Young; Shin, Pyung-Gyun; Jang, Kab-Yeul; Yoo, Young-Bok; Park, Young-Jin; Lee, Byoung-Moo; Sung, Gi-Ho; James, Timothy Y.; Kong, Won-Sik

    2011-01-01

    Background Mating-type loci of mushroom fungi contain master regulatory genes that control recognition between compatible nuclei, maintenance of compatible nuclei as heterokaryons, and fruiting body development. Regions near mating-type loci in fungi often show adapted recombination, facilitating the generation of novel mating types and reducing the production of self-compatible mating types. Compared to other fungi, mushroom fungi have complex mating-type systems, showing both loci with redundant function (subloci) and subloci with many alleles. The genomic organization of mating-type loci has been solved in very few mushroom species, which complicates proper interpretation of mating-type evolution and use of those genes in breeding programs. Methodology/Principal Findings We report a complete genetic structure of the mating-type loci from the tetrapolar, edible mushroom Flammulina velutipes mating type A3B3. Two matB3 subloci, matB3a that contains a unique pheromone and matB3b, were mapped 177 Kb apart on scaffold 1. The matA locus of F. velutipes contains three homeodomain genes distributed over 73 Kb distant matA3a and matA3b subloci. The conserved matA region in Agaricales approaches 350 Kb and contains conserved recombination hotspots showing major rearrangements in F. velutipes and Schizophyllum commune. Important evolutionary differences were indicated; separation of the matA subloci in F. velutipes was diverged from the Coprinopsis cinerea arrangement via two large inversions whereas separation in S. commune emerged through transposition of gene clusters. Conclusions/Significance In our study we determined that the Agaricales have very large scale synteny at matA (∼350 Kb) and that this synteny is maintained even when parts of this region are separated through chromosomal rearrangements. Four conserved recombination hotspots allow reshuffling of large fragments of this region. Next to this, it was revealed that large distance subloci can exist in matB as

  8. Characterization of Phytophthora infestans populations in Colombia: first report of the A2 mating type.

    PubMed

    Vargas, Angela M; Quesada Ocampo, Lina M; Céspedes, Maria Catalina; Carreño, Natalia; González, Adriana; Rojas, Alejandro; Zuluaga, A Paola; Myers, Kevin; Fry, William E; Jiménez, Pedro; Bernal, Adriana J; Restrepo, Silvia

    2009-01-01

    Phytophthora infestans, the causal agent of late blight in crops of the Solanaceae family, is one of the most important plant pathogens in Colombia. Not only are Solanum lycopersicum, and S. tuberosum at risk, but also several other solanaceous hosts (Physalis peruviana, S. betaceum, S. phureja, and S. quitoense) that have recently gained importance as new crops in Colombia may be at risk. Because little is known about the population structure of Phytophthora infestans in Colombia, we report here the phenotypic and molecular characterization of 97 isolates collected from these six different solanaceous plants in Colombia. All the isolates were analyzed for mating type, mitochondrial haplotypes, genotype for several microsatellites, and sequence of the internal transcribed spacer (ITS) region. This characterization identified a single individual of A2 mating type (from Physalis peruviana) for the first time in Colombia. All isolates had an ITS sequence that was at least 97% identical to the consensus sequence. Of the 97 isolates, 96 were mitochondrial haplotype IIa, with the single A2 isolate being Ia. All isolates were invariant for the microsatellites. Additionally, isolates collected from S. tuberosum and P. peruviana (64 isolates) were tested for: aggressiveness on both hosts, genotype for the isozymes (glucose-6-phosphate isomerase and peptidase), and restriction fragment length polymorphism fingerprint pattern as detected by RG57. Isolates from S. tuberosum were preferentially pathogenic on S. tuberosum, and isolates from P. peruviana were preferentially pathogenic on P. peruviana. The population from these two hosts was dominated by a single clonal lineage (59 of 64 individuals assayed), previously identified from Ecuador and Peru as EC-1. This lineage was mating type A1, IIa for mitochondrial DNA, invariant for two microsatellites, and invariant for both isozymes. The remaining four A1 isolates were in lineages very closely related to EC-1 (named EC-1.1, CO

  9. Multiple epigenetic events regulate mating-type switching of fission yeast.

    PubMed

    Klar, A J; Ivanova, A V; Dalgaard, J Z; Bonaduce, M J; Grewal, S I

    1998-01-01

    Two epigenetic events at mat1, one of which is DNA strand specific, are required to initiate recombination during mating-type switching. The third, a chromosomally borne imprinted event at the mat2/3 interval regulates silencing and directionality of switching, and prohibits interchromosomal recombination. We speculate that the unit of inheritance in the mat2/3 interval is both DNA plus its associated chromatin structure. Such a control is likely to be essential in maintaining particular states of gene expression during development.

  10. Mating-type orthologous genes in the primarily homothallic Moniliophthora perniciosa, the causal agent of Witches' Broom Disease in cacao.

    PubMed

    Kües, Ursula; Navarro-González, Mónica

    2010-10-01

    The cacao-pathogenic Moniliophthora perniciosa C-biotype is a primarily homothallic Agaricomycete of which the genome has recently become available. Searching of the genome sequence with mating type proteins from other basidiomycetes detected one or possibly two potential genes for HD1 homeodomain transcription factors, 7 or possibly 8 genes for potential pheromone receptors and five genes for putative pheromone precursors. Apparently, the fungus possesses gene functions encoded in the tetrapolar basidiomycetes in the A and B mating loci, respectively. In the tetrapolar species, the A and B mating type genes govern formation of clamp cells at hyphal septa of the dikaryon and their fusion with sub-apical cells as well as mushroom production. The C-biotype forms fused clamp cells and also basidiocarps on mycelia germinated from basidiospores and their development might be controlled by the detected genes. It represents the first example of a primarily homothallic basidiomycete where A - and B -mating-type-like genes were found. Various strategies are discussed as how self-compatibility in presence of such genes can evolve. An A -mating-type like gene for an HD2 homeodomain transcription factor is, however, not included in the available sequence representing estimated 69% coverage of the haploid genome but there are non-mating genes for other homeodomain transcription factors of currently unknown function that are conserved in basidiomycetes and also various ascomycetes.

  11. Genome-Wide Gene Expression Profiling of Fertilization Competent Mycelium in Opposite Mating Types in the Heterothallic Fungus Podospora anserina

    PubMed Central

    Coppin, Evelyne; Imbeaud, Sandrine; Grognet, Pierre; Delacroix, Hervé; Debuchy, Robert

    2011-01-01

    Background Mating-type loci in yeasts and ascomycotan filamentous fungi (Pezizomycotina) encode master transcriptional factors that play a critical role in sexual development. Genome-wide analyses of mating-type-specification circuits and mating-type target genes are available in Saccharomyces cerevisiae and Schizosaccharomyces pombe; however, no such analyses have been performed in heterothallic (self-incompatible) Pezizomycotina. The heterothallic fungus Podospora anserina serves as a model for understanding the basic features of mating-type control. Its mat+ and mat− mating types are determined by dissimilar allelic sequences. The mat− sequence contains three genes, designated FMR1, SMR1 and SMR2, while the mat+ sequence contains one gene, FPR1. FMR1 and FPR1 are the major regulators of fertilization, and this study presents a genome-wide view of their target genes and analyzes their target gene regulation. Methodology/Principal Findings The transcriptomic profiles of the mat+ and mat− strains revealed 157 differentially transcribed genes, and transcriptomic analysis of fmr1− and fpr1− mutant strains was used to determine the regulatory actions exerted by FMR1 and FPR1 on these differentially transcribed genes. All possible combinations of transcription repression and/or activation by FMR1 and/or FPR1 were observed. Furthermore, 10 additional mating-type target genes were identified that were up- or down-regulated to the same level in mat+ and mat− strains. Of the 167 genes identified, 32 genes were selected for deletion, which resulted in the identification of two genes essential for the sexual cycle. Interspecies comparisons of mating-type target genes revealed significant numbers of orthologous pairs, although transcriptional profiles were not conserved between species. Conclusions/Significance This study represents the first comprehensive genome-wide analysis of mating-type direct and indirect target genes in a heterothallic filamentous fungus

  12. Transcription of the mating-type-regulated lncRNA IRT1 is governed by TORC1 and PKA.

    PubMed

    Moretto, Fabien; van Werven, Folkert J

    2016-08-12

    Cell fate decisions are controlled by multiple cell-intrinsic and -extrinsic factors. In budding yeast, the decision to enter gametogenesis or sporulation is dictated by nutrient availability and mating type. Recently, we showed that in diploid cells harbouring opposite mating types (MATa and MATα), the protein kinase A (PKA) and target of rapamycin complex I (TORC1) signalling pathways integrate at the promoter of the master regulatory transcription factor IME1 to control sporulation via nutrient availability (Weidberg, et al. 2016). In cells with a single mating type (MATa or MATα), however, IME1 is repressed by transcription through the IME1 promoter of a long non-coding RNA called IRT1, which prevents this cell type from undergoing sporulation. Here, we investigated the role of nutrient signalling in mating-type control of IME1. We find that expression of IRT1, like IME1 itself, depends on nutrient availability and the activities of PKA and TORC1. IRT1 transcription is repressed when nutrients are ample and TORC1 and PKA are active. In contrast, inhibition of PKA and TORC1 is sufficient to recruit Rme1 to the IRT1 promoter and induce IRT1-mediated repression of IME1. Finally, we provide evidence that IRT1 and IME1 are co-repressed by the Tup1-Cyc8 complex when nutrients are ample. Thus, in cells with a single mating-type nutrient availability regulates mating-type repression of IME1 and sporulation. Our results indicate that there is a hierarchy between nutrient and mating-type signals in controlling the decision to enter sporulation.

  13. Recovery of Saccharomyces cerevisiae mating-type a cells from G1 arrest by alpha factor.

    PubMed Central

    Chan, R K

    1977-01-01

    Mating-type a cells of the yeast Saccharomyces cerevisiae that had been specifically arrested in the G1 phase of the cell cycle by alpha factor, an oligopeptide pheromone made by alpha cells, recovered and resumed cell division after a period of inhibition which was dependent on the concentration of alpha factor used. These treated a cells were more resistant to alpha factor than untreated a cells, but lost their resistance upon further cell division. However, cells arrested for 6 h were no more resistant to alpha factor than cells arrested for only 2.5 h. Mating-type a strains could inactivate or remove alpha factor from the culture fluid, but two a sterile (nonmating) mutants and an a/alpha diploid strain could not. These results suggest that a cells have a mechanism, which may involve uptake or inactivation of alpha factor, for recovering from alpha factor arrest. However, the results do not distinguish between a recovery mechanism which is constitutive and one which is induced by alpha factor. The loss of alpha factor activity during recovery appeared to be primarily cell contact mediated, although an extracellular, diffusible inhibitor of alpha factor that is labile or that functions stoichiometrically could not be ruled out. PMID:400792

  14. Orientation of DNA replication establishes mating-type switching pattern in S. pombe.

    PubMed

    Dalgaard, J Z; Klar, A J

    1999-07-08

    The fission yeast Schizosaccharomyces pombe normally has haploid cells of two mating types, which differ at the chromosomal locus mat1. After two consecutive asymmetric cell divisions, only one in four 'grand-daughter' cells undergoes a 'mating-type switch', in which genetic information is transferred to mat1 from the mat2-P or mat3-M donor loci. This switching pattern probably results from an imprinting event at mat1 that marks one sister chromatid in a strand-specific manner, and is related to a site-specific, double-stranded DNA break at mat1. Here we show that the genetic imprint is a strand-specific, alkali-labile DNA modification at mat1. The DNA break is an artefact, created from the imprint during DNA purification. We also propose and test the model that mat1 is preferentially replicated by a centromere-distal origin(s), so that the strand-specific imprint occurs only during lagging-strand synthesis. Altering the origin of replication, by inverting mat1 or introducing an origin of replication, affects the imprinting and switching efficiencies in predicted ways. Two-dimensional gel analysis confirmed that mat1 is preferentially replicated by a centromere-distal origin(s). Thus, the DNA replication machinery may confer different developmental potential to sister cells.

  15. Hemolysin and K antigens in relation to serotype and hemagglutination type of Escherichia coli isolated from extraintestinal infections.

    PubMed Central

    Evans, D J; Evans, D G; Höhne, C; Noble, M A; Haldane, E V; Lior, H; Young, L S

    1981-01-01

    Escherichia coli isolated from cases of bacteremia and from a variety of urinary tract infections were characterized according to serotype (O:H antigenicity), K type (possession of K1, K2, K3, K12, or K13), hemagglutination (HA) type, and production of beta-hemolysin. Results obtained with the bacteremia and urinary tract infection isolates were similar except for more hemolytic isolated from urine than from blood (42 versus 29%) and more K1+ isolates from blood than from urine (50 versus 29%). A close correlation was found between Ha type VI (production of fimbriae which mediate mannose-resistant HA of human and African green monkey erythrocytes) and the production of hemolysin or K1 capsular antigen or both. Most (95 of 98, or 95%) of the HA type VI+ blood isolates and most (146 of 164, or 89%) of the HA type VI+ urine isolates produced hemolysin or K1 or both, in contrast to 22 and 26%, respectively, of those belonging to HA types other than HA type VI. Also, 76% of all hemolytic and 70% of all K1+ isolates belonged to HA type VI. Remarkably few of the HA type VI+ isolates (13%) and even fewer of the HA type VI- isolates (3%) produced both K1 and hemolysin; these belonged mainly to serotypes O16:H6, O18:H7 and O2:H4. Other major serogroups were usually K1+/hemolysin- (O1, O7) or K1-/hemolysin+ (O2, O4, O6). At least 74% (262 of 351) and possibly as many as 83% (293 of 351) of those isolates which produced mannose-resistant HA of human erythrocytes were classified as HA type VI+; 31 isolates produced mannose-resistant HA with all erythrocytes tested. Taking serogroup and serotype into consideration, we conclude that the E. coli fimbrial hemagglutinin(s) responsible for the HA type VI phenotype will prove to be the same as the virulence-associated mannose-resistant adhesins of uropathogenic E. coli which other investigators have characterized as unique fimbrial antigens detectable by mannose-resistant HA of human erythrocytes. PMID:7007421

  16. Transient inhibition of histone deacetylase activity overcomes silencing in the mating-type region in fission yeast.

    PubMed

    Olsson, T G; Silverstein, R A; Ekwall, K; Sunnerhagen, P

    1999-03-01

    We have investigated the effects of inhibition of histone de-acetylase activity on silencing at the silent mating-type loci in fission yeast. Treatment of exponentially growing cells with the histone deacetylase inhibitor, trichostatin A (TSA), resulted in derepression of a marker gene inserted 150 bp distal from the silent mat3-M locus. The natural targets for the silencing mechanism in this region were only partially derepressed and the activation appeared to be asymmetric, i.e. the mat2-P cassette remained silent at concentrations that clearly partially derepressed the mat3-M cassette. We further noted that treatment of wild-type h90 cells resulted in the generation of altered sporulation phenotypes, indicating that the treatment affected the expression of mating-type genes and/or mating-type switching. The results are discussed in the light of recent accumulated data regarding the role of deacetylation for silencing in other species.

  17. Directionality of Fission Yeast Mating-Type Interconversion Is Controlled by the Location of the Donor Loci

    PubMed Central

    Thon, G.; Klar, AJS.

    1993-01-01

    Cells of homothallic strains of Schizosaccharomyces pombe efficiently switch between two mating types called P and M. The phenotypic switches are due to conversion of the expressed mating-type locus (mat1) by two closely linked silent loci, mat2-P and mat3-M, that contain unexpressed information for the P and M mating types, respectively. In this process, switching-competent cells switch to the opposite mating type in 72-90% of the cell divisions. Hence, mat2-P is a preferred donor of information to mat1 in M cells, whereas mat3-M is a preferred donor in P cells. We investigated the reason for the donor preference by constructing a strain in which the genetic contents of the donor loci were swapped. We found that switching to the opposite mating type was very inefficient in that strain. This shows that the location of the silent cassettes in the chromosome, rather than their content, is the deciding factor for recognition of the donor for each cell type. We propose a model in which switching is achieved by regulating accessibility of the donor loci, perhaps by changing the chromatin structure in the mating-type region, thus promoting an intrachromosomal folding of mat2 or mat3 onto mat1 in a cell type-specific fashion. We also present evidence for the involvement of the Swi6 and Swi6-mod trans-acting factors in the donor-choice mechanism. We suggest that these factors participate in forming the proposed folded structure. PMID:8375648

  18. Directionality of fission yeast mating-type interconversion is controlled by the location of the donor loci.

    PubMed

    Thon, G; Klar, A J

    1993-08-01

    Cells of homothallic strains of Schizosaccharomyces pombe efficiently switch between two mating types called P and M. The phenotypic switches are due to conversion of the expressed mating-type locus (mat1) by two closely linked silent loci, mat2-P and mat3-M, that contain unexpressed information for the P and M mating types, respectively. In this process, switching-competent cells switch to the opposite mating type in 72-90% of the cell divisions. Hence, mat2-P is a preferred donor of information to mat1 in M cells, whereas mat3-M is a preferred donor in P cells. We investigated the reason for the donor preference by constructing a strain in which the genetic contents of the donor loci were swapped. We found that switching to the opposite mating type was very inefficient in that strain. This shows that the location of the silent cassettes in the chromosome, rather than their content, is the deciding factor for recognition of the donor for each cell type. We propose a model in which switching is achieved by regulating accessibility of the donor loci, perhaps by changing the chromatin structure in the mating-type region, thus promoting an intrachromosomal folding of mat2 or mat3 onto mat1 in a cell type-specific fashion. We also present evidence for the involvement of the Swi6 and Swi6-mod trans-acting factors in the donor-choice mechanism. We suggest that these factors participate in forming the proposed folded structure.

  19. Unconventional Recombination in the Mating Type Locus of Heterothallic Apple Canker Pathogen Valsa mali

    PubMed Central

    Yin, Zhiyuan; Ke, Xiwang; Li, Zhengpeng; Chen, Jiliang; Gao, Xiaoning; Huang, Lili

    2017-01-01

    Sexual reproduction in filamentous ascomycetes is controlled by the mating type (MAT) locus, including two idiomorphs MAT1-1 and MAT1-2. Understanding the MAT locus can provide clues for unveiling the sexual development and virulence factors for fungal pathogens. The genus Valsa (Sordariomycetes, Diaporthales) contains many tree pathogens responsible for destructive canker diseases. The sexual stage of these ascomycetes is occasionally observed in nature, and no MAT locus has been reported to date. Here, we identified the MAT locus of the apple canker pathogen Valsa mali, which causes extensive damage, and even death, to trees. V. mali is heterothallic in that each isolate carries either the MAT1-1 or MAT1-2 idiomorph. However, the MAT structure is distinct from that of many other heterothallic fungi in the Sordariomycetes. Two flanking genes, COX13 and APN2, were coopted into the MAT locus, possibly by intrachromosomal rearrangement. After the acquisition of foreign genes, unequal recombination occurred between MAT1-1/2 idiomorphs, resulting in a reverse insertion in the MAT1-2 idiomorph. Evolutionary analysis showed that the three complete MAT1-1-2, COX13, and APN2 genes in this region diverged independently due to different selection pressure. Null hypothesis tests of a 1:1 MAT ratio of 86 V. mali isolates from four different provinces showed a relatively balanced distribution of the two idiomorphs in the fields. These results provide insights into the evolution of the mating systems in Sordariomycetes. PMID:28228472

  20. Mating Type and Simple Sequence Repeat Markers Indicate a Clonal Population of Phyllosticta citricarpa in Florida.

    PubMed

    Wang, Nan-Yi; Zhang, Ke; Huguet-Tapia, Jose C; Rollins, Jeffrey A; Dewdney, Megan M

    2016-11-01

    Phyllosticta citricarpa, the citrus black spot pathogen, was first identified in Florida in March 2010. Subsequently, this pathogen has become established in Florida but can be easily confused with the endemic nonpathogenic citrus endophyte P. capitalensis. In this study, the mating-type (MAT) loci of P. citricarpa and P. capitalensis were identified via draft genome sequencing and were characterized at the structural and sequence levels. P. citricarpa was determined to have an idiomorphic, heterothallic MAT locus structure, whereas P. capitalensis was found to have a single MAT locus consistent with a homothallic mating system. A survey of P. citricarpa isolates from Florida revealed that only the MAT1-2 idiomorph existed in the Floridian population. In contrast, isolates collected from Australia exhibited a 1:1 ratio of MAT1-1 and MAT1-2 isolates. Development and analysis of simple sequence repeat markers revealed a single multilocus genotype (MLG) in the Floridian population (n = 70) and 11 MLG within the Australian population (n = 24). These results indicate that isolates of P. citricarpa from Florida are likely descendent from a single clonal lineage and are reproducing asexually. The disease management focus in Florida will need to be concentrated on the production and dispersal of pycnidiospores.

  1. Genetic structure of the mating-type locus of Chlamydomonas reinhardtii.

    PubMed Central

    Ferris, Patrick J; Armbrust, E Virginia; Goodenough, Ursula W

    2002-01-01

    Portions of the cloned mating-type (MT) loci (mt(+) and mt(-)) of Chlamydomonas reinhardtii, defined as the approximately 1-Mb domains of linkage group VI that are under recombinational suppression, were subjected to Northern analysis to elucidate their coding capacity. The four central rearranged segments of the loci were found to contain both housekeeping genes (expressed during several life-cycle stages) and mating-related genes, while the sequences unique to mt(+) or mt(-) carried genes expressed only in the gametic or zygotic phases of the life cycle. One of these genes, Mtd1, is a candidate participant in gametic cell fusion; two others, Mta1 and Ezy2, are candidate participants in the uniparental inheritance of chloroplast DNA. The identified housekeeping genes include Pdk, encoding pyruvate dehydrogenase kinase, and GdcH, encoding glycine decarboxylase complex subunit H. Unusual genetic configurations include three genes whose sequences overlap, one gene that has inserted into the coding region of another, several genes that have been inactivated by rearrangements in the region, and genes that have undergone tandem duplication. This report extends our original conclusion that the MT locus has incurred high levels of mutational change. PMID:11805055

  2. Drug Resistance Is Not Directly Affected by Mating Type Locus Zygosity in Candida albicans

    PubMed Central

    Pujol, Claude; Messer, Shawn A.; Pfaller, Michael; Soll, David R.

    2003-01-01

    Recently, evidence was presented that in a collection of fluconazole-resistant strains of Candida albicans there was a much higher proportion of homozygotes for the mating type locus (MTL) than in a collection of fluconazole-sensitive isolates, suggesting the possibility that when cells become MTL homozygous they acquire intrinsic drug resistance. To investigate this possibility, an opposite strategy was employed. First, drug susceptibility was measured in a collection of isolates selected for MTL homozygosity. The majority of these isolates had not been exposed to antifungal drugs. Second, the level of drug susceptibility was compared between spontaneously generated MTL-homozygous progeny and their MTL-heterozygous parent strains which had not been exposed to antifungal drugs. The results demonstrate that naturally occurring MTL-homozygous strains are not intrinsically more drug resistant, supporting the hypotheses that either the higher incidence of MTL homozygosity previously demonstrated among fluconazole-resistant isolates involved associated homozygosity of a drug resistance gene linked to the MTL locus, or that MTL-homozygous strains may be better at developing drug resistance upon exposure to the drug than MTL-heterozygous strains. Furthermore, the results demonstrate that a switch by an MTL-homozygous strain from the white to opaque phenotype, the latter functioning as the facilitator of mating, does not notably alter drug susceptibility. PMID:12654648

  3. Evaluation of counterimmunoelectrophoresis for serotyping Actinobacillus pleuropneumoniae isolates and detection of type-specific antigens in lungs of infected pigs.

    PubMed Central

    Mittal, K R; Bourdon, S; Berrouard, M

    1993-01-01

    A rapid, simple, and accurate counterimmunoelectrophoresis technique was developed for serotyping cultures of Actinobacillus pleuropneumoniae as well as for detection of their type-specific antigens in the lung tissues of infected pigs. The counterimmunoelectrophoresis test correctly identified all of the reference antigens and more than 99% of 1,200 field isolates of A. pleuropneumoniae representing the 12 established serotypes within 1 h. Counterimmunoelectrophoresis and coagglutination tests did not differ broadly in sensitivity from each other. Both procedures were more rapid and more sensitive than immunodiffusion and indirect hemagglutination tests. A total of 355 lung tissue samples (130 lungs of pigs that died because of acute respiratory problems, 125 lungs of pigs from herds with chronically infected pleuropneumonia, and 100 lungs from apparently healthy pigs at the slaughterhouse) were examined for the presence of A. pleuropneumoniae type-specific antigens by counterimmunoelectrophoresis, coagglutination, and immunodiffusion tests. A. pleuropneumoniae type-specific antigen was found in all 55 samples from which the bacteria had earlier been isolated and in 27 specimens in which they had not been found. Detection of antigen in the lung tissues by coagglutination and counterimmunoelectrophoresis tests was found to be much simpler and much more rapid than conventional culture isolation. Both counterimmunoelectrophoresis and coagglutination tests were found extremely useful in the diagnosis of acute cases of porcine pleuropneumonia. However, these techniques were able to detect only some of the chronically infected carrier pigs. PMID:8408552

  4. Identification and In Situ Distribution of a Fungal Gene Marker: The Mating Type Genes of the Black Truffle.

    PubMed

    De la Varga, Herminia; Murat, Claude

    2016-01-01

    Truffles are ectomycorrhizal fungi harvested mainly in human managed agroforestry ecosystems. Truffle production in truffle orchards faces two important bottlenecks or challenges: the initiation of the sexual reproduction and the growth of the ascocarps during several months. The black Périgord truffle, Tuber melanosporum, is a heterothallic species and the mating type genes (MAT1-1 and M1T1-2) have been characterized. In this context, the unraveling of the T. melanosporum mating type strains distribution in truffle orchards is a critical starting point to provide new insights into its sexual reproduction. The aim of this chapter is to present the protocol used to characterize the T. melanosporum mating type present in a truffle orchard from ascocarps, hazel mycorrhizal root tips, and/or soil samples, by polymerase chain reactions using specific primers for those genes, but it can be adapted for other fungal species.

  5. Incidence of childhood pneumonia and serotype and sequence-type distribution in Streptococcus pneumoniae isolates in Japan.

    PubMed

    Tanaka, J; Ishiwada, N; Wada, A; Chang, B; Hishiki, H; Kurosaki, T; Kohno, Y

    2012-06-01

    The 7-valent pneumococcal conjugate vaccine (PCV7) is reported to decrease the incidence of community-acquired pneumonia (CAP) in children. To determine the annual incidence of CAP before the introduction of PCV7, we counted the number of children hospitalized with CAP between 2008 and 2009 in Chiba City, Japan. We investigated serotype and multilocus sequence typing (MLST) for Streptococcus pneumoniae isolates in CAP cases. The annual incidence of hospitalized CAP in children aged <5 years was 17.6 episodes/1000 child-years. In 626 episodes, S. pneumoniae was dominant in 14.7% and 0.8% of sputum and blood samples, respectively. The most common serotypes were 6B, 23F and 19F. The coverage rates of PCV7 were 66.7% and 80% in sputum samples and blood samples, respectively. MLST analysis revealed 37 sequence types. Furthermore, 54.1% of the sputum isolates and 40% of the blood isolate were related to international multidrug-resistant clones.

  6. The DNA Repair Protein yKu80 Regulates the Function of Recombination Enhancer during Yeast Mating Type Switching†

    PubMed Central

    Ruan, Chun; Workman, Jerry L.; Simpson, Robert T.

    2005-01-01

    Recombination enhancer (RE) is essential for regulating donor preference during yeast mating type switching. In this study, by using minichromosome affinity purification (MAP) and mass spectrometry, we found that yeast Ku80p is associated with RE in MATa cells. Chromatin immunoprecipitation assays confirmed its occupancy in vivo. Deletion of YKU80 results in altered chromatin structure in the RE region and more importantly causes a dramatic decrease of HML usage in MATa cells. We also detect directional movement of yKu80p from the RE towards HML during switching. These results indicate a novel function of yeast Ku80p in regulating mating type switching. PMID:16166630

  7. The pedigree pattern of mating-type switching in Schizosaccharomyces pombe.

    PubMed

    Egel, R

    1984-04-01

    The previous ovservation that in dividing sister cells of Schizosaccharomyces pombe only one of two parallel divisions can be accompanied by a switch of mating type, herein termed "Miyata's rule", has been confirmed in pedigrees of diploid cells heterozygous for the mat2-Pm-B102 allele. Moreover, this rule appears to operate at the level of individual chromosomes, since in diploid cells simultaneous single-switch events were frequently observed in both sister cells, albeit on different chromosomes. Assuming two successive precursory states for the smt switching signal to the right of mat1, a deterministic 3-step model coupled to the cell cycle has been fitted to the empirical frequency distribution of conjugation in "four-lined cells" (a minipedigree of dividing sister cells). The nature of the first intermediate is still unknown, while the ultimate precursor of a switching event is probably a double-strand cut at smt, which can be revealed by molecular analyses.

  8. Population structure and mating-type genes of Colletotrichum graminicola from Agrostis palustris.

    PubMed

    Chen, Fajun; Goodwin, Paul H; Khan, Adalat; Hsiang, Tom

    2002-05-01

    Eighty-seven isolates of Colletotrichum graminicola, mostly from Agrostis palustris, were collected in grass fields, most of which were in Ontario, Canada. Specific primers were designed to amplify the mating-type (MAT) genes and, among 35 isolates tested, all yielded a band of the expected size for MAT2. For six isolates, the MAT2 PCR products were sequenced and found to be similar to that reported for MAT2 of C. graminicola from maize. Based on 119 polymorphic bands from 10 random amplified polymorphic DNA primers, analyses of genetic distances were found to generally cluster isolates by host and geographic origin. Among 42 isolates from a grass field in Ontario, significant spatial autocorrelation was found to occur within a 20-m distance, implying that this is the effective propagule dispersal distance. Although clonal propagation was observed in the 87 isolates with 67 unique genotypes, the extent of genetic variation in local populations implies some occurrence of sexual or asexual recombination.

  9. A MAT1–2 wild-type strain from Penicillium chrysogenum: functional mating-type locus characterization, genome sequencing and mating with an industrial penicillin-producing strain

    PubMed Central

    Böhm, Julia; Dahlmann, Tim A; Gümüşer, Hendrik; Kück, Ulrich

    2015-01-01

    In heterothallic ascomycetes, mating is controlled by two nonallelic idiomorphs that determine the ‘sex’ of the corresponding strains. We recently discovered mating-type loci and a sexual life cycle in the penicillin-producing fungus, Penicillium chrysogenum. All industrial penicillin production strains worldwide are derived from a MAT1-1 isolate. No MAT1-2 strain has been investigated in detail until now. Here, we provide the first functional analysis of a MAT1-2 locus from a wild-type strain. Similar to MAT1-1, the MAT1-2 locus has functions beyond sexual development. Unlike MAT1-1, the MAT1-2 locus affects germination and surface properties of conidiospores and controls light-dependent asexual sporulation. Mating of the MAT1-2 wild type with a MAT1-1 high penicillin producer generated sexual spores. We determined the genomic sequences of parental and progeny strains using next-generation sequencing and found evidence for genome-wide recombination. SNP calling showed that derived industrial strains had an uneven distribution of point mutations compared with the wild type. We found evidence for meiotic recombination in all chromosomes. Our results point to a strategy combining the use of mating-type genes, genetics, and next-generation sequencing to optimize conventional strain improvement methods. PMID:25521009

  10. Molecular organization of the mating-type loci in the homothallic Ascomycete Eupenicillium crustaceum.

    PubMed

    Pöggeler, Stefanie; O'Gorman, Céline M; Hoff, Birgit; Kück, Ulrich

    2011-07-01

    Eupenicillium species are the teleomorphic (sexual) forms of anamorphic (asexual) members of the genus Penicillium, which contains many species of industrial importance. Here we describe the first molecular analysis of the mating-type (MAT) locus from a homothallic (self-fertile) Eupenicillium species, E. crustaceum. This ascomycete is a sexual relative of the penicillin producer Penicillium chrysogenum, which while long considered asexual, was recently shown to possess the required genetic machinery for heterothallic breeding. The E. crustaceum genome contains two MAT loci, MAT1-1 and MAT1-2, in an arrangement characteristic of other known homothallic euascomycetes, such as Neosartorya fischeri. MAT1-1 is flanked by conserved APN2 (DNA lyase) and SLA2 (cytoskeleton assembly control) genes and encodes a homologue of the α-box domain protein MAT1-1-1. Conversely, MAT1-2 carries a HMG-domain gene MAT1-2-1, and is flanked by a degenerate SLA2 gene and an intact homologue of the P. chrysogenum ORF Pc20g08960. Here we demonstrate the transcriptional expression of both mating-type genes during vegetative development. Furthermore, the MAT1-1-1 and MAT1-2-1 sequences were used to resolve the phylogenetic relationship of E. crustaceum with other ascomycetes. Phylogenetic trees confirmed a very close relationship between the homothallic E. crustaceum and the supposedly heterothallic P. chrysogenum. This close taxonomic association makes E. crustaceum an ideal candidate for future expression and evolutionary studies of sexual reproduction, with the ultimate aim of inducing sex in P. chrysogenum.

  11. Gene Conversion Occurs within the Mating-Type Locus of Cryptococcus neoformans during Sexual Reproduction

    PubMed Central

    Sun, Sheng; Hsueh, Yen-Ping; Heitman, Joseph

    2012-01-01

    Meiotic recombination of sex chromosomes is thought to be repressed in organisms with heterogametic sex determination (e.g. mammalian X/Y chromosomes), due to extensive divergence and chromosomal rearrangements between the two chromosomes. However, proper segregation of sex chromosomes during meiosis requires crossing-over occurring within the pseudoautosomal regions (PAR). Recent studies reveal that recombination, in the form of gene conversion, is widely distributed within and may have played important roles in the evolution of some chromosomal regions within which recombination was thought to be repressed, such as the centromere cores of maize. Cryptococcus neoformans, a major human pathogenic fungus, has an unusually large mating-type locus (MAT, >100 kb), and the MAT alleles from the two opposite mating-types show extensive nucleotide sequence divergence and chromosomal rearrangements, mirroring characteristics of sex chromosomes. Meiotic recombination was assumed to be repressed within the C. neoformans MAT locus. A previous study identified recombination hot spots flanking the C. neoformans MAT, and these hot spots are associated with high GC content. Here, we investigated a GC-rich intergenic region located within the MAT locus of C. neoformans to establish if this region also exhibits unique recombination behavior during meiosis. Population genetics analysis of natural C. neoformans isolates revealed signals of homogenization spanning this GC-rich intergenic region within different C. neoformans lineages, consistent with a model in which gene conversion of this region during meiosis prevents it from diversifying within each lineage. By analyzing meiotic progeny from laboratory crosses, we found that meiotic recombination (gene conversion) occurs around the GC-rich intergenic region at a frequency equal to or greater than the meiotic recombination frequency observed in other genomic regions. We discuss the implications of these findings with regards to the

  12. Genetic diversity of the mating type and toxin production genes in Pyrenophora tritici-repentis.

    PubMed

    Lepoint, P; Renard, M-E; Legrève, A; Duveiller, E; Maraite, H

    2010-05-01

    Pyrenophora tritici-repentis, the causal agent of tan spot on wheat, is a homothallic loculoascomycete with a complex race structure. The objectives of this study were to confirm the homothallic nature of the pathogen, characterize mating type diversity and toxin production genes in a global collection of strains, and analyze how these traits are associated between each other and with existing races. The pseudothecia production capacity, race identification, mating type locus (MAT), internal transcribed spacer, and glyceraldehyde-3-phosphate dehydrogenase regions were analyzed in a selection of 88 strains originating from Europe, North and South America, North Africa, and Central and South Asia. Some (60%) strains produced pseudothecia containing ascospores, independent of their origin. Race identification obtained using the multiplex polymerase chain reaction targeting host-selective toxin (HST) genes was consistent, overall, with the results based on the inoculation of a set of differential wheat cultivars and confirmed the predominance of race 1/2 strains ( approximately 83%). However, discrepancies in race identification, differences from the reference tester strains, and atypical ToxA profiles suggest the presence of new races and HSTs. The MAT1-1 and MAT1-2 coding regions are consecutively arranged in a single individual, suggesting putative heterothallic origin of P. tritici-repentis. Upstream from the MAT is an open reading frame of unknown function (ORF1) containing a MAT-specific degenerate carboxy-terminus. The phylogenetic analysis of the MAT locus reveals two distinct groups, unlinked to geographical origin or ToxA profile. Group I, the best-represented group, is associated with typical tan spot lesions caused by races 1, 2, 3, and 5 on wheat. It is more homogenous than group II encompassing race 4 strains, as well as isolates associated primarily with small spot lesions on wheat leaves or other hosts. Group II could contain several distinct taxa.

  13. Computerized restriction endonuclease analysis compared with O-serotype and phage type in the epidemiologic fingerprinting of Pseudomonas aeruginosa strains.

    PubMed

    Garaizar, Javier; Latorre, Mikel; López-Molina, Nuria; Laconcha, Idoia; Alberdi, Leire; Rementeria, Aitor; Audicana, Ana; Uliarte, Rosario; Cisterna, Ramón

    1997-04-01

    OBJECTIVE: To assess restriction endonuclease analysis (REA) of chromosomal DNA using SalI enzyme, low-concentration (0.4%) agarose gels and digitalized data management of the REA patterns obtained for the typing of clinical Pseudomonas aeruginosa isolates. METHODS: A group of 67 clinical unrelated isolates from 10 Spanish hospitals was used to study the discriminatory power, reproducibility and typeability of REA typing. RESULTS: A SalI REA pattern consisted of a variety (1--10) of restriction bands in the range between 12.2 and 48.5 kb and an unresolvable smear of low-molecular-weight bands. Forty different SalI REA patterns with an index of discrimination of 0.979 were obtained. Low typeability (91.04%) was the major limitation of REA typing. Analysis of blinded subcultures of eight Pseudomonas aeruginosa strains showed the reproducibility of REA typing to be 87.5%. Combined phenotypic typing (O-serotyping and phage typing) performed on the same group of strains showed comparable discrimination but much lower reproducibility. Isolates selected from five clusters of nosocomial infections in hospitals in the UK were typed by REA typing, and the results show high agreement when compared with conventional phenotypic typing methods in distinguishing between strains. CONCLUSIONS: These data underline the usefulness of REA typing enhanced with digitalized data management for the epidemiologic subtyping of clinical Pseudomonas aeruginosa isolates.

  14. Stringent mating-type-regulated auxotrophy increases the accuracy of systematic genetic interaction screens with Saccharomyces cerevisiae mutant arrays.

    PubMed

    Singh, Indira; Pass, Rebecca; Togay, Sine Ozmen; Rodgers, John W; Hartman, John L

    2009-01-01

    A genomic collection of haploid Saccharomyces cerevisiae deletion strains provides a unique resource for systematic analysis of gene interactions. Double-mutant haploid strains can be constructed by the synthetic genetic array (SGA) method, wherein a query mutation is introduced by mating to mutant arrays, selection of diploid double mutants, induction of meiosis, and selection of recombinant haploid double-mutant progeny. The mechanism of haploid selection is mating-type-regulated auxotrophy (MRA), by which prototrophy is restricted to a particular haploid genotype generated only as a result of meiosis. MRA escape leads to false-negative genetic interaction results because postmeiotic haploids that are supposed to be under negative selection instead proliferate and mate, forming diploids that are heterozygous at interacting loci, masking phenotypes that would be observed in a pure haploid double-mutant culture. This work identified factors that reduce MRA escape, including insertion of terminator and repressor sequences upstream of the MRA cassette, deletion of silent mating-type loci, and utilization of alpha-type instead of a-type MRA. Modifications engineered to reduce haploid MRA escape reduced false negative results in SGA-type analysis, resulting in >95% sensitivity for detecting gene-gene interactions.

  15. The Clr1 Locus Regulates the Expression of the Cryptic Mating-Type Loci of Fission Yeast

    PubMed Central

    Thon, G.; Klar, AJS.

    1992-01-01

    The mat2-P and mat3-M loci of fission yeast contain respectively the plus (P) and minus (M) mating-type information in a transcriptionally silent state. That information is transposed from the mat2 or mat3 donor locus via recombination into the expressed mating-type locus (mat1) resulting in switching of the cellular mating type. We have identified a gene, named clr1 (for cryptic loci regulator), whose mutations allow expression of the mat2 and mat3 loci. clr1 mutants undergo aberrant haploid meiosis, indicative of transcription of the silent genes. Production of mRNA from mat3 is detectable in clr1 mutants. Furthermore, the ura4 gene inserted near mat3, weakly expressed in wild-type cells, is derepressed in clr1 mutants. The clr1 mutations also permit meiotic recombination in the 15-kb mat2-mat3 interval, where recombination is normally inhibited. The clr1 locus is in the right arm of chromosome II. We suggest that clr1 regulates silencing of the mat2 and mat3 loci, and participates in establishing the ``cold spot'' for recombination by organizing the chromatin structure of the mating-type region. PMID:1644273

  16. The clr1 locus regulates the expression of the cryptic mating-type loci of fission yeast.

    PubMed

    Thon, G; Klar, A J

    1992-06-01

    The mat2-P and mat3-M loci of fission yeast contain respectively the plus (P) and minus (M) mating-type information in a transcriptionally silent state. That information is transposed from the mat2 or mat3 donor locus via recombination into the expressed mating-type locus (mat1) resulting in switching of the cellular mating type. We have identified a gene, named clr1 (for cryptic loci regulator), whose mutations allow expression of the mat2 and mat3 loci. clr1 mutants undergo aberrant haploid meiosis, indicative of transcription of the silent genes. Production of mRNA from mat3 is detectable in clr1 mutants. Furthermore, the ura4 gene inserted near mat3, weakly expressed in wild-type cells, is derepressed in clr1 mutants. The clr1 mutations also permit meiotic recombination in the 15-kb mat2-mat3 interval, where recombination is normally inhibited. The clr1 locus is in the right arm of chromosome II. We suggest that clr1 regulates silencing of the mat2 and mat3 loci, and participates in establishing the "cold spot" for recombination by organizing the chromatin structure of the mating-type region.

  17. Optimal Serotype Compositions for Pneumococcal Conjugate Vaccination under Serotype Replacement

    PubMed Central

    Nurhonen, Markku; Auranen, Kari

    2014-01-01

    Pneumococcal conjugate vaccination has proved highly effective in eliminating vaccine-type pneumococcal carriage and disease. However, the potential adverse effects of serotype replacement remain a major concern when implementing routine childhood pneumococcal conjugate vaccination programmes. Applying a concise predictive model, we present a ready-to-use quantitative tool to investigate the implications of serotype replacement on the net effectiveness of vaccination against invasive pneumococcal disease (IPD) and to guide in the selection of optimal vaccine serotype compositions. We utilise pre-vaccination data on pneumococcal carriage and IPD and assume partial or complete elimination of vaccine-type carriage, its replacement by non-vaccine-type carriage, and stable case-to-carrier ratios (probability of IPD per carriage episode). The model predicts that the post-vaccination IPD incidences in Finland for currently available vaccine serotype compositions can eventually decrease among the target age group of children <5 years of age by 75%. However, due to replacement through herd effects, the decrease among the older population is predicted to be much less (20–40%). We introduce a sequential algorithm for the search of optimal serotype compositions and assess the robustness of inferences to uncertainties in data and assumptions about carriage and IPD. The optimal serotype composition depends on the age group of interest and some serotypes may be highly beneficial vaccine types in one age category (e.g. 6B in children), while being disadvantageous in another. The net effectiveness will be improved only if the added serotype has a higher case-to-carrier ratio than the average case-to-carrier ratio of the current non-vaccine types and the degree of improvement in effectiveness depends on the carriage incidence of the serotype. The serotype compositions of currently available pneumococcal vaccines are not optimal and the effectiveness of vaccination in the

  18. A multiplex PCR assay for determination of mating type in isolates of the honey bee fungal pathogen, Ascosphaera apis

    USDA-ARS?s Scientific Manuscript database

    In this study we developed a multiplex PCR for identification of mating type idiomorphs in the filamentous fungus, Ascosphaera apis, the causative agent of chalkbrood disease in the honey bee (Apis melliffera). A combination of gene-specific primers was designed to amplify Mat1-1 and Mat1-2 gene fra...

  19. The Hos2 Histone Deacetylase Controls Ustilago maydis Virulence through Direct Regulation of Mating-Type Genes

    PubMed Central

    Elías-Villalobos, Alberto; Fernández-Álvarez, Alfonso; Moreno-Sánchez, Ismael; Helmlinger, Dominique; Ibeas, José I.

    2015-01-01

    Morphological changes are critical for host colonisation in plant pathogenic fungi. These changes occur at specific stages of their pathogenic cycle in response to environmental signals and are mediated by transcription factors, which act as master regulators. Histone deacetylases (HDACs) play crucial roles in regulating gene expression, for example by locally modulating the accessibility of chromatin to transcriptional regulators. It has been reported that HDACs play important roles in the virulence of plant fungi. However, the specific environment-sensing pathways that control fungal virulence via HDACs remain poorly characterised. Here we address this question using the maize pathogen Ustilago maydis. We find that the HDAC Hos2 is required for the dimorphic switch and pathogenic development in U. maydis. The deletion of hos2 abolishes the cAMP-dependent expression of mating type genes. Moreover, ChIP experiments detect Hos2 binding to the gene bodies of mating-type genes, which increases in proportion to their expression level following cAMP addition. These observations suggest that Hos2 acts as a downstream component of the cAMP-PKA pathway to control the expression of mating-type genes. Interestingly, we found that Clr3, another HDAC present in U. maydis, also contributes to the cAMP-dependent regulation of mating-type gene expression, demonstrating that Hos2 is not the only HDAC involved in this control system. Overall, our results provide new insights into the role of HDACs in fungal phytopathogenesis. PMID:26317403

  20. Characterization of Ascochyta rabiei for population structure, mating type and pathogenic variability from Pakistan and United States

    USDA-ARS?s Scientific Manuscript database

    Chickpea production is greatly hampered by blight causing fungal pathogen Ascochyta rabiei (AR) in chickpea growing regions of the world. Genetic variability and mating type frequency of thirty-two AR isolates from six geographical regions of Pakistan were compared with a US-AR population. Pakistani...

  1. Mating-type distribution and genetic diversity of Cercospora sojina populations on soybean from Arkansas: evidence for potential sexual reproduction.

    PubMed

    Kim, Hun; Newell, Annakay D; Cota-Sieckmeyer, Robyn G; Rupe, John C; Fakhoury, Ahmad M; Bluhm, Burton H

    2013-10-01

    Cercospora sojina causes frogeye leaf spot of soybean, which can cause serious economic losses in the United States. In this study, 132 C. sojina isolates were collected from six fields (from two counties, Cross and Crawford) in Arkansas. To determine mating type, a multiplex polymerase chain reaction assay was developed with primers specific for C. sojina. Of the 132 isolates, 68 isolates had the MAT1-1-1 idiomorph and 64 isolates had the MAT1-2 idiomorph; no isolates possessed both idiomorphs. Both mating types were present in a variety of spatial scales, including separate lesions on individual leaves. Clone-corrected data from eight microsatellites indicated that mating-type loci were present in approximately equal proportions in all populations analyzed, which suggests that Arkansas populations of C. sojina are undergoing cryptic sexual reproduction. All six populations evaluated had high genotypic diversity of 26 to 79%. In addition, among strains isolated from a single leaf, multiple and distinct haplotypes were associated with both mating types, supporting the hypothesis that sexual reproduction occurs within the populations. Most populations showed significant gametic disequilibrium but levels of disequilibrium were relatively low, particularly in populations from Crawford County. A low differentiation index (GST) was observed for all simple-sequence repeat markers across all populations. Furthermore, the value of G statistics between populations suggests that significant genetic exchange exists among the populations. Taken together, these results demonstrate that C. sojina populations from Arkansas are genetically diverse and most likely undergoing sexual reproduction.

  2. Trans-acting factors and properly positioned DNA elements repress mating-type genes in fission yeast.

    PubMed

    Ekwall, K; Olsson, T; Ruusala, T

    1992-04-01

    Repression of the mating-type P genes at the silent mat2-P locus in fission yeast is dependent on four cis-acting DNA elements, two on each side of the coding sequences. The mechanism by which these elements exert their influence on the mating-type promoter is studied here by insertion of a bacterial antibiotic resistance gene at several positions in the silent region. The behavior of the resistance gene itself, and the changes its insertion causes in mating-type expression, reveal that the repressive elements have a limited range of action and that the four elements have unequal effects on gene expression. Repression of the antibiotic resistance gene inside the silent region leads to an antibiotic-sensitive phenotype and facilitates the selection of resistant mutants. These mutants can de-repress the resistance gene at other positions than the one used for their selection. Strong antibiotic resistance correlates with derepression of the plasmid-borne mating-type cassette. These data argue that mat2-P repression is dependent on trans-acting factors and the positioning of the repressive DNA elements, but less dependent on the nature of the affected promoter.

  3. Mating-Type Mutations in SCHIZOSACCHAROMYCES POMBE: Isolation of Mutants and Analysis of Strains with an h- or h+ Phenotype

    PubMed Central

    Meade, James H.; Gutz, Herbert

    1976-01-01

    Mutants defective in various steps of the sexual cycle have been isolated from homothallic strains of Schizosaccharomyces pombe by Bresch, Müller and Egel (1968). These mutants include heterothallic h+ and h- strains. We have isolated additional h+ and h- mutants from homothallic strains. Those mutants which are due to mutations in the mating-type region were analyzed in detail. Our results show that the mating-type gene mat2 not only has a function in copulation and meiosis, but that it also regulates the formation of the map1 gene product (map1 is a mating-type auxiliary gene). Some of the h - mutants have lost only one of the three functions while others are defective in at least two, and perhaps all three, functions. Further, we show that the mat1- allele of h90 strains can mutate to mat1+ but that mutations in mat2 appear to affect the mutational behavior of mat1. Finally, we describe a new inactive mating-type allele, mat2*, which is different from mat20 in that it can mutate to mat2+. PMID:17248713

  4. Mating-Type Mutations in SCHIZOSACCHAROMYCES POMBE: Isolation of Mutants and Analysis of Strains with an h or h Phenotype.

    PubMed

    Meade, J H; Gutz, H

    1976-06-01

    Mutants defective in various steps of the sexual cycle have been isolated from homothallic strains of Schizosaccharomyces pombe by Bresch, Müller and Egel (1968). These mutants include heterothallic h(+) and h(-) strains. We have isolated additional h(+) and h(- ) mutants from homothallic strains. Those mutants which are due to mutations in the mating-type region were analyzed in detail. Our results show that the mating-type gene mat2 not only has a function in copulation and meiosis, but that it also regulates the formation of the map1 gene product (map1 is a mating-type auxiliary gene). Some of the h( -) mutants have lost only one of the three functions while others are defective in at least two, and perhaps all three, functions. Further, we show that the mat1(-) allele of h(90) strains can mutate to mat1(+) but that mutations in mat2 appear to affect the mutational behavior of mat1. Finally, we describe a new inactive mating-type allele, mat2*, which is different from mat2(0) in that it can mutate to mat2(+).

  5. Characterization of the mycelial compatibility groups and mating type alleles in populations of Sclerotinia minor in central China

    USDA-ARS?s Scientific Manuscript database

    Ninety-five single-sclerotium isolates were obtained from lettuce and weeds in three counties in central China. They were identified belonging to Sclerotinia minor Jagger based on colony morphology and the S. minor-specific DNA marker. Mycelial compatibility groups (MCGs) and the mating type (MAT) a...

  6. DNA polymorphism in recombining and non-recombing mating-type-specific loci of the smut fungus Microbotryum

    PubMed Central

    Votintseva, A A; Filatov, D A

    2011-01-01

    The population-genetic processes leading to the genetic degeneration of non-recombining regions have mainly been studied in animal and plant sex chromosomes. Here, we report population genetic analysis of the processes in the non-recombining mating-type-specific regions of the smut fungus Microbotryum violaceum. M. violaceum has A1 and A2 mating types, determined by mating-type-specific ‘sex chromosomes' that contain 1–2 Mb long non-recombining regions. If genetic degeneration were occurring, then one would expect reduced DNA polymorphism in the non-recombining regions of this fungus. The analysis of DNA diversity among 19 M. violaceum strains, collected across Europe from Silene latifolia flowers, revealed that (i) DNA polymorphism is relatively low in all 20 studied loci (π∼0.15%), (ii) it is not significantly different between the two mating-type-specific chromosomes nor between the non-recombining and recombining regions, (iii) there is substantial population structure in M. violaceum populations, which resembles that of its host species, S. latifolia, and (iv) there is significant linkage disequilibrium, suggesting that widespread selfing in this species results in a reduction of the effective recombination rate across the genome. We hypothesise that selfing-related reduction of recombination across the M. violaceum genome negates the difference in the level of DNA polymorphism between the recombining and non-recombining regions, and may possibly lead to similar levels of genetic degeneration in the mating-type-specific regions of the non-recombining ‘sex chromosomes' and elsewhere in the genome. PMID:21081967

  7. Local Outbreak of Listeria monocytogenes Serotype 4b Sequence Type 6 Due to Contaminated Meat Pâté.

    PubMed

    Althaus, Denise; Jermini, Marco; Giannini, Petra; Martinetti, Gladys; Reinholz, Danuta; Nüesch-Inderbinen, Magdalena; Lehner, Angelika; Stephan, Roger

    2017-04-01

    In January and February 2016, five cases of confirmed and two cases of probable infection due to Listeria monocytogenes serotype 4b, sequence type (ST) 6 belonging to a single pulsed-field gel electrophoresis pulsotype pattern were registered in a region of southern Switzerland. L. monocytogenes was detected in blood samples (four cases) and pleural fluid (one case). Furthermore, L. monocytogenes 4b ST6 was detected in a stool sample of an asymptomatic person exposed to a common food. Forthwith, the food safety authority and a local gourmet meat producer reported L. monocytogenes contamination of meat pâté. Analysis of further food and environmental samples from the premises of the producer yielded isolates matching the clinical strains and confirmed the presence of L. monocytogenes 4b ST6 in the mincing machine as the cause of the food contamination.

  8. Emergence of KPC-producing Klebsiella pneumoniae hypervirulent clone of capsular serotype K1 that belongs to sequence type 11 in Mainland China.

    PubMed

    Wei, Dan-Dan; Wan, La-Gen; Deng, Qiong; Liu, Yang

    2016-06-01

    KPC-2 has been rarely reported in hypervirulent Klebsiella pneumoniae strains. Here, we describe a KPC-2-producing K. pneumoniae hypervirulent clone of capsular serotype K1 belonging to sequence type 11. The presence of KPC carbapenemase in hypervirulent clone could mark an evolutionary step toward its establishment as major nosocomial pathogen. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Functional characterization of MAT1-1-specific mating-type genes in the homothallic ascomycete Sordaria macrospora provides new insights into essential and nonessential sexual regulators.

    PubMed

    Klix, V; Nowrousian, M; Ringelberg, C; Loros, J J; Dunlap, J C; Pöggeler, S

    2010-06-01

    Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular basis of homothallism and the role of mating-type genes during fruiting-body development, we deleted each of the three genes, SmtA-1 (MAT1-1-1), SmtA-2 (MAT1-1-2), and SmtA-3 (MAT1-1-3), contained in the MAT1-1 part of the mating-type locus of the homothallic ascomycete species Sordaria macrospora. Phenotypic analysis of deletion mutants revealed that the PPF domain protein-encoding gene SmtA-2 is essential for sexual reproduction, whereas the alpha domain protein-encoding genes SmtA-1 and SmtA-3 play no role in fruiting-body development. By means of cross-species microarray analysis using Neurospora crassa oligonucleotide microarrays hybridized with S. macrospora targets and quantitative real-time PCR, we identified genes expressed under the control of SmtA-1 and SmtA-2. Both genes are involved in the regulation of gene expression, including that of pheromone genes.

  10. Population structure of hyperinvasive serotype 12F, clonal complex 218 Streptococcus pneumoniae revealed by multilocus boxB sequence typing

    PubMed Central

    Rakov, Alexey V.; Ubukata, Kimiko; Robinson, D. Ashley

    2011-01-01

    At least four outbreaks of invasive disease caused by serotype 12F, clonal complex 218 Streptococcus pneumoniae have occurred in the United States over the past two decades. We studied the population structure of this clonal complex using a sample of 203 outbreak and surveillance isolates that were collected over 22 years from 34 US states and eight other countries. Conventional multilocus sequence typing identified five types and distinguished a single outbreak from the others. To improve typing resolution, multilocus boxB sequence typing (MLBT) was developed from 10 variable boxB minisatellite loci. MLBT identified 86 types and distinguished between each of the four outbreaks. Diversity across boxB loci tended to be positively correlated with repeat array size and, overall, best fit the infinite alleles mutation model. Multilocus linkage disequilibrium was strong, but pairwise disequilibrium decreased with the physical distance between loci and was strongest in one large region of the chromosome, indicating recent recombinations. Two major clusters were identified in the sample, and they were differentiated geographically, as western and more easterly US clusters, and temporally, as clusters that predominated before and after the licensure of pneumococcal conjugate vaccines. The diversity and linkage disequilibrium within these two clusters also differed, suggesting different population dynamics. MLBT revealed hidden aspects of the population structure of these hyperinvasive pneumococci, and it may provide a useful adjunct tool for outbreak investigations, surveillance, and population genetics studies of other pneumococcal clonal complexes. PMID:21888992

  11. Genetic variation, occurrence of mating types and different forms of Pyrenophora teres causing net blotch of barley in Finland.

    PubMed

    Serenius, Marjo; Mironenko, Nina; Manninen, Outi

    2005-07-01

    The amplified fragment length polymorphism (AFLP) was used to study genetic variation in Pyrenophora teres causing net blotch of barley in Finland. The mean similarity was 93% between all isolates and a bit higher within two distinct populations based on 175 AFLP markers. Despite the high genetic similarity, 70 unique AFLP genotypes were identified among 72 isolates. Most of the genetic variation (68.5%) was observed within a field population and a smaller portion (30.3%) between them. Significant genetic differentiation (Fst = 0.308, P < 0.001) was identified between field populations. However only 1.2% of the variation was observed between mating types within a field and a lack of genetic differentiation (Fsc = 0.017, P = 0.087) was observed. The occurrence of the form of blotch (spot type, f. sp. maculata, or net type, P. teres f. sp. teres) was identified with specific PCR. All isolates were found to be of the net type. The existence of both mating types (MAT1 and MAT2) was identified for the first time in Finland and the ratio of the two mating types was almost 1:1 in both locations. The evolutionary potential and the possibility of sexual reproduction of P. teres occurring in Finland are discussed.

  12. Mating Type Gene (MAT) and Itraconazole Susceptibility of Trichophyton tonsurans Strains Isolated in Japan.

    PubMed

    Hiruma, Junichiro; Okubo, Miki; Kano, Rui; Kumagawa, Mai; Hiruma, Masataro; Hasegawa, Atsuhiko; Kamata, Hiroshi; Tsuboi, Ryoji

    2016-06-01

    Infection by Trichophyton tonsurans is an emerging fungal epidemic in Japan. Itraconazole (ITZ) and terbinafine have been used for the treatment of this infection for 15 years. However, patients with T. tonsurans infections have been shown to remain uncured or to become reinfected, suggesting that subclinical infection or polyphyletic strains and/or antifungal drug-resistant strains might be occurring in Japan. In this study, PCR analysis was performed to confirm the presence of the mating type locus MAT in genomic DNA from 60 Japanese clinical isolates of T. tonsurans, and to assess the previously postulated clonal origin of clinical isolates of this species. Antifungal susceptibility testing on isolates also was performed to confirm the absence of strains resistant to ITZ. PCR analysis proved that all 60 strains contained the MAT1-1 allele, while none contained the MAT1-2 allele. As determined by E-test, the mean MIC of ITZ in the 60 strains was 0.023 mg/L (range 0.002-0.125 mg/L). All strains of T. tonsurans isolated in Japan were clonal and were not resistant to ITZ. Therefore, dermatophytosis due to T. tonsurans is expected to respond to ITZ, since clinical isolates of T. tonsurans tested to date have been susceptible to this antifungal. This infection is proliferating as a subclinical infection in Japan.

  13. Using mating-type gene sequences for improved phylogenetic resolution of Collectotrichum species complexes.

    PubMed

    Du, Meizhu; Schardl, Christopher L; Nuckles, Etta M; Vaillancourt, Lisa J

    2005-01-01

    Colletotrichum species are defined primarily on the basis of host preference and morphology of the organism in planta and in culture. However the genus contains several species complexes that encompass such a broad range of morphological and pathological variation that the species name is of relatively little use either to the taxonomist or plant pathologist. Phylogenetic analyses, primarily based on variable regions of the ribosomal DNA (rDNA) sequences, have indicated that these species complexes comprise a variable number of identifiable monophyletic clades. However rDNA sequences often are insufficiently diverse to fully resolve such closely related lineages. A group of isolates representing three species complexes (C. graminicola, C. gloeosporioides and C. acutatum) were analyzed by using the high mobility group (HMG)-encoding sequence of the MAT1-2 mating type sequence, which has been shown in other fungi to be especially suitable for distinguishing relationships among closely related groups. Results were compared with those obtained from analysis of variable regions of the rDNA as well as from standard morphological classification methods. Results achieved through analysis of MAT1-2 sequences correlated well with those obtained by analysis of rDNA sequences but provided significantly better resolution among the various lineages. Morphological traits, including hyphopodia size, colony appearance, spore size, appresorial shape and size and host preference, frequently were unreliable as indicators of phylogenetic association. Spore shape and hyphopodia shape more often were useful for this purpose.

  14. Isolation site influences virulence phenotype of serotype 14 Streptococcus pneumoniae strains belonging to multilocus sequence type 15.

    PubMed

    Amin, Zarina; Harvey, Richard M; Wang, Hui; Hughes, Catherine E; Paton, Adrienne W; Paton, James C; Trappetti, Claudia

    2015-12-01

    Streptococcus pneumoniae is a diverse species causing invasive as well as localized infections that result in massive global morbidity and mortality. Strains vary markedly in pathogenic potential, but the molecular basis is obscured by the diversity and plasticity of the pneumococcal genome. We have previously reported that S. pneumoniae serotype 3 isolates belonging to the same multilocus sequence type (MLST) differed markedly in in vitro and in vivo phenotypes, in accordance with the clinical site of isolation, suggesting stable niche adaptation within a clonal lineage. In the present study, we have extended our analysis to serotype 14 clinical isolates from cases of sepsis or otitis media that belong to the same MLST (ST15). In a murine intranasal challenge model, five ST15 isolates (three from blood and two from ears) colonized the nasopharynx to similar extents. However, blood and ear isolates exhibited significant differences in bacterial loads in other host niches (lungs, ear, and brain) at both 24 and 72 h postchallenge. In spite of these differences, blood and ear isolates were present in the lungs at similar levels at 6 h postchallenge, suggesting that early immune responses may underpin the distinct virulence phenotypes. Transcriptional analysis of lung tissue from mice infected for 6 h with blood isolates versus ear isolates revealed 8 differentially expressed genes. Two of these were exclusively expressed in response to infection with the ear isolate. These results suggest a link between the differential capacities to elicit early innate immune responses and the distinct virulence phenotypes of clonally related S. pneumoniae strains.

  15. [Surveillance of Haemophilus influenzae serotypes in Argentina from 2005 to 2010 during the Haemophilus influenzae type b conjugate vaccine era].

    PubMed

    Efron, Adriana M; Moscoloni, María A; Reijtman, Vanesa R; Regueira, Mabel

    2013-01-01

    The introduction of the Haemophilus influenzae type b vaccine in the immunization programs of many countries has greatly reduced this invasive disease and the carriage caused by this serotype, also increasing other capsular types and non-capsular isolations. There were 313 isolations of H. influenzae under study, which were recovered from a sterile site coming from pediatric and adult patients carrying the invasive disease. Patients were treated at 90 different hospitals belonging to the Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas (National Lab Network for Meningitis and Acute Bacterial Respiratory Infections) from 2005 to 2010 for the following disorders: pneumonia, 40.3% (n=126), meningitis, 30.0% (n=94) and bacteremia, 26.5% (n=83). In pediatric patients (n=279), the highest frequency of isolations corresponded to children under the age of 2 years, 74.5% (n=208). Regarding type distribution, 61.3% corresponded to non-capsular H. influenzae (n=192), 20.1% to type b (n=63), 11.2% to type a (n=35), 4.8% to type f, and 2.6% to other types. Capsular H. influenzae was predominant in meningitis whereas non-capsular H. influenzae in pneumonia and bacteremia. The biotype was determined in 306 isolations. The totality (100%) of type a (n=35) was biotype II whereas 66.7% of type b (n=63) was biotype I. Slide agglutination and PCR tests were used in 220 isolations. There was a match of 0.982 (IC: 0.92-1.00) between them. During the last year, there was a great increase in type b, showing the importance of clinical and laboratory-based surveillance of the invasive disease caused by H. influenzae.

  16. Characterization and distribution of mating-type genes of the turfgrass pathogen Sclerotinia homoeocarpa on a global scale.

    PubMed

    Putman, Alexander I; Tredway, Lane P; Carbone, Ignazio

    2015-08-01

    Sclerotinia homoeocarpa F.T. Bennett is a filamentous member of Ascomycota that causes dollar spot, the most economically important disease of turfgrass worldwide. We sequenced and characterized the mating-type (MAT) locus of four recently-collected contemporary strains causing dollar spot, four historical type strains used to describe the fungus, and three species of Rutstroemiaceae. Moreover, we developed a multiplex PCR assay to screen 1019 contemporary isolates for mating-type. The organization of the MAT loci of all strains examined could be classified into one of four categories: (1) putatively heterothallic, as exemplified by all contemporary strains and three of four historical type strains; (2) putatively heterothallic with a deleted putative gene in the MAT1-2 idiomorph, as detected in strains from two recently-collected populations in the United Kingdom that show more similarity to historical strains; (3) putatively homothallic with close physical linkage between MAT1-1-1 and MAT1-2-1, as found in one historical type strain of S. homoeocarpa and two strains of Rutstroemia cuniculi; and (4) an unresolved but apparently homothallic organization in which strains contained both MAT1-1-1 and MAT1-2-1 but linkage between these genes and between the two flanking genes could not be confirmed, as identified in R. paludosa and Poculum henningsianum. In contemporary S. homoeocarpa populations there was no significant difference in the frequency of the two mating types in clone-corrected samples when analyzed on regional and local scales, suggesting sex may be possible in this pathogen. However, two isolates from Italy and twenty from California were heterokaryotic for both complete heterothallic MAT idiomorphs. Results from this study contribute to knowledge about mating systems in filamentous fungi and enhance our understanding of the evolution and biology of an important plant pathogen. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Transplacental and oral transmission of wild-type bluetongue virus serotype 8 in cattle after experimental infection.

    PubMed

    Backx, Anoek; Heutink, René; van Rooij, Eugene; van Rijn, Piet

    2009-09-18

    Potential vertical transmission of wild-type bluetongue virus serotype 8 (BTV-8) in cattle was explored in this experiment. We demonstrated transplacental transmission of wild-type BTV-8 in one calf and oral infection with BTV-8 in another calf. Following the experimental BTV-8 infection of seven out of fifteen multi-parous cows eight months in gestation, each newborn calf was tested prior to colostrum intake for transplacental transmission of BTV by RRT-PCR. If transplacental transmission was not established the calves were fed colostrum from infected dams or colostrum from non-infected dams spiked with BTV-8 containing blood. One calf from an infected dam was born RRT-PCR positive and BTV-specific antibody (Abs) negative, BTV was isolated from its blood. It was born with clinical signs resembling bluetongue and lived for two days. Its post-mortem tissue suspensions were RRT-PCR positive. Of the seven calves fed colostrum from infected dams, none became infected. Of the six calves fed colostrum from non-infected dams spiked with infected blood, one calf became PCR-positive at day 8 post-partum (dpp), seroconverted 27 days later, and remained RRT-PCR and Abs positive for the duration of the experiment (i.e., 70dpp). This work demonstrates that transplacental transmission in late gestation and oral infection of the neonate with wild-type BTV-8 is possible in cattle under experimental conditions.

  18. Localization and properties of a silencing element near the mat3-M mating-type cassette of Schizosaccharomyces pombe.

    PubMed Central

    Thon, G; Bjerling, K P; Nielsen, I S

    1999-01-01

    Transcription is repressed in a segment of Schizosaccharomyces pombe chromosome II that encompasses the mat2-P and mat3-M mating-type cassettes. Chromosomal deletion analysis revealed the presence of a repressor element within 500 bp of mat3-M. This element acted in synergy with the trans-acting factors Swi6, Clr1, Clr2, Clr3, and Clr4 and had several properties characteristic of silencers: it did not display promoter specificity, being able to silence not only the M mating-type genes but also the S. pombe ura4 and ade6 genes placed on the centromere-distal side of the mat3-M cassette; it could repress a gene when placed further than 2.6 kb from the promoter and it acted in both orientations, although with different efficiencies, the natural orientation repressing more stringently than the reverse. Following deletion of this element, two semistable states of expression of the mat3-M region were observed and these two states could interconvert. The deletion did not affect gene expression in the vicinity of the mat2-P cassette, 11 kb away from mat3-M. Conversely, deleting 1.5 kb on the centromere-proximal side of the mat2-P cassette, which was previously shown to partially derepress transcription around mat2-P, had no effect on gene expression near mat3-M. A double deletion removing the mat2-P and mat3-M repressor elements had the same effect as the single deletions on their respective cassettes when assayed in cells of the M mating type. These observations allow us to refine a model proposing that redundant pathways silence the mating type region of S. pombe. PMID:10049914

  19. Localization and properties of a silencing element near the mat3-M mating-type cassette of Schizosaccharomyces pombe.

    PubMed

    Thon, G; Bjerling, K P; Nielsen, I S

    1999-03-01

    Transcription is repressed in a segment of Schizosaccharomyces pombe chromosome II that encompasses the mat2-P and mat3-M mating-type cassettes. Chromosomal deletion analysis revealed the presence of a repressor element within 500 bp of mat3-M. This element acted in synergy with the trans-acting factors Swi6, Clr1, Clr2, Clr3, and Clr4 and had several properties characteristic of silencers: it did not display promoter specificity, being able to silence not only the M mating-type genes but also the S. pombe ura4 and ade6 genes placed on the centromere-distal side of the mat3-M cassette; it could repress a gene when placed further than 2.6 kb from the promoter and it acted in both orientations, although with different efficiencies, the natural orientation repressing more stringently than the reverse. Following deletion of this element, two semistable states of expression of the mat3-M region were observed and these two states could interconvert. The deletion did not affect gene expression in the vicinity of the mat2-P cassette, 11 kb away from mat3-M. Conversely, deleting 1.5 kb on the centromere-proximal side of the mat2-P cassette, which was previously shown to partially derepress transcription around mat2-P, had no effect on gene expression near mat3-M. A double deletion removing the mat2-P and mat3-M repressor elements had the same effect as the single deletions on their respective cassettes when assayed in cells of the M mating type. These observations allow us to refine a model proposing that redundant pathways silence the mating type region of S. pombe.

  20. Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

    PubMed

    Pandey, Ravi S; Azad, Rajeev K

    2016-03-01

    Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non

  1. The MAT1-2-1 mating-type gene upregulates photo-inducible carotenoid biosynthesis in Fusarium verticillioides.

    PubMed

    Adám, Attila L; García-Martínez, Jorge; Szucs, Endre P; Avalos, Javier; Hornok, László

    2011-05-01

    Filamentous ascomycetes, including mitotic holomorphs, have constitutively transcribed MAT (mating type) genes. These genes encode transcription factors considered to be the major regulators of sexual communication. The proven targets of the MAT transcription factors are pheromone precursor and pheromone receptor genes. However, recent studies demonstrated that MAT proteins may also affect other genes not involved directly in the mating process. When grown in the light, Fusarium verticillioides produces the acidic xanthophyll neurosporoxanthin and lower amounts of nonpolar precursor carotenes, such as phytoene, torulene, β-carotene, and γ-carotene. Depending on the illumination conditions, a drastic decrease or the absence of light-inducible carotenoid accumulation was detected in three independent ΔFvMAT1-2-1 knockout mutants of F. verticillioides as compared with the parental wild-type strain. Transcript levels of the carB, carRA, and carT genes, encoding key enzymes of the carotenoid biosynthetic pathway, were also significantly reduced in the mutants. The downregulation of these genes in the ΔFvMAT1-2-1 mutant indicates that MAT genes play a role in the control of carotenogenesis in Fusarium. The finding that mating-type genes regulate important processes unrelated to sex helps to understand the presence of functional MAT genes in asexually reproducing fungus populations. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  2. Organization and Evolutionary Trajectory of the Mating Type (MAT) Locus in Dermatophyte and Dimorphic Fungal Pathogens▿ †

    PubMed Central

    Li, Wenjun; Metin, Banu; White, Theodore C.; Heitman, Joseph

    2010-01-01

    Sexual reproduction in fungi is governed by a specialized genomic region, the mating type (MAT) locus, whose gene identity, organization, and complexity are diverse. We identified the MAT locus of five dermatophyte fungal pathogens (Microsporum gypseum, Microsporum canis, Trichophyton equinum, Trichophyton rubrum, and Trichophyton tonsurans) and a dimorphic fungus, Paracoccidioides brasiliensis, and performed phylogenetic analyses. The identified MAT locus idiomorphs of M. gypseum control cell type identity in mating assays, and recombinant progeny were produced. Virulence tests in Galleria mellonella larvae suggest the two mating types of M. gypseum may have equivalent virulence. Synteny analysis revealed common features of the MAT locus shared among these five dermatophytes: namely, a small size (∼3 kb) and a novel gene arrangement. The SLA2, COX13, and APN2 genes, which flank the MAT locus in other Ascomycota are instead linked on one side of the dermatophyte MAT locus. In addition, the transcriptional orientations of the APN2 and COX13 genes are reversed compared to the dimorphic fungi Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii. A putative transposable element, pogo, was found to have inserted in the MAT1-2 idiomorph of one P. brasiliensis strain but not others. In conclusion, the evolution of the MAT locus of the dermatophytes and dimorphic fungi from the last common ancestor has been punctuated by both gene acquisition and expansion, and asymmetric gene loss. These studies further support a foundation to develop molecular and genetic tools for dermatophyte and dimorphic human fungal pathogens. PMID:19880755

  3. DNA vaccine encoding type IV pilin of Actinobacillus pleuropneumoniae induces strong immune response but confers limited protective efficacy against serotype 2 challenge.

    PubMed

    Lu, Yu-Chun; Li, Min-Chen; Chen, Yi-Min; Chu, Chun-Yen; Lin, Shuen-Fuh; Yang, Wen-Jen

    2011-10-13

    Actinobacillus pleuropneumoniae is a gram-negative bacterial pathogen that causes swine pleuropneumonia, a highly contagious and often fatal disease that occurs worldwide. Our previous study showed that DNA vaccines encoding Apx exotoxin structural proteins ApxIA and/or ApxIIA, are a promising novel approach for immunization against the lethal challenge of A. pleuropneumoniae serotype 1. Vaccination against A. pleuropneumoniae is impeded by the lack of vaccines inducing reliable cross-serotype protection. Type IV fimbrial protein ApfA has been shown to be present and highly conserved in various serotypes of A. pleuropneumoniae. A novel DNA vaccine encoding ApfA (pcDNA-apfA) was constructed to evaluate the protective efficacy against infection with A. pleuropneumoniae serotype 2. A significant antibody response against pilin was generated following pcDNA-apfA immunization, suggesting that it was expressed in vivo. The IgG subclass (IgG1 and IgG2a) analysis indicates that the pcDNA-apfA vaccine induces both Th1 and Th2 immune responses. The IgA analysis shows that mucosal immunity could be enhanced by this DNA vaccine. Nevertheless, the strong antibody response induced by pcDNA-apfA vaccine only provided limited 30% protective efficacy against the serotype 2 challenge. These results in this study do not coincide with that the utility of type IV pilin is a good vaccine candidate against other infectious pathogens. It indicates that pilin should play a limited role in the development of a vaccine against A. pleuropneumoniae infection.

  4. Primers for mating-type diagnosis in Diaporthe and Phomopsis: their use in teleomorph induction in vitro and biological species definition.

    PubMed

    Santos, Jorge M; Correia, Viviana G; Phillips, Alan J L

    2010-01-01

    Sexual reproduction in ascomycete fungi is governed by the mating-type (MAT) locus. The MAT loci of Diaporthe and its Phomopsis anamorphs differ in only one gene: MAT1-1-1 in mating-type MAT1-1 and MAT1-2-1 in mating-type MAT1-2. In order to diagnose mating-types in Diaporthe and Phomopsis and evaluate their usefulness in teleomorph induction in vitro and biological species delimitation, we designed primers that amplify part of the MAT1-1-1 and MAT1-2-1 genes. MAT phylogenies were generated and compared with ITS and EF1-α phylograms. Species recognised in the EF1-α phylogeny corresponded directly with those determined in the MAT phylogenies. ITS was shown to be highly variable resulting in a large number of phylogenetic species that were discordant with MAT and EF1-α species. Mating experiments were conducted to evaluate the existence of reproductive barriers between some isolates, and their anamorphic morphologies were compared. The primers proved to be useful in the mating-type diagnosis of isolates, selection of compatible mating pairs, and in the assessment of biological species boundaries. Copyright © 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  5. Control of yeast cell type by the mating type locus: positive regulation of the alpha-specific STE3 gene by the MAT alpha 1 product.

    PubMed

    Sprague, G F; Jensen, R; Herskowitz, I

    1983-02-01

    The mating type locus (MAT) determines the three yeast cell types, a, alpha, and a/alpha. It has been proposed that alleles of this locus, MATa and MAT alpha, encode regulators that control expression of unlinked genes necessary for mating and sporulation. Specifically, the alpha 1 product of MAT alpha is proposed to be a positive regulator of alpha-specific genes. To test this view, we have assayed RNA production from the alpha-specific STE3 gene in the three cell types and in mutants defective in MAT alpha. The STE3 gene was cloned by screening a yeast genomic clone bank for plasmids that complement the mating defect of ste3 mutants. Using the cloned STE3 gene as a probe, we find that alpha cells produce STE3 RNA, whereas a and a/alpha cells do not. Furthermore, mat alpha 1 mutants do not produce STE3 RNA, whereas mat alpha 2 mutants do. These results show that the STE3 gene, required for mating only by alpha cells, is expressed only in alpha cells. They show also that production of RNA from the STE3 gene requires that alpha 1 product of MAT alpha. Thus alpha 1 positively regulates at least one alpha-specific gene by increasing the level of that gene's RNA product.

  6. Gametogenesis in the Chlamydomonas reinhardtii minus mating type is controlled by two genes, MID and MTD1.

    PubMed

    Lin, Huawen; Goodenough, Ursula W

    2007-06-01

    In the unicellular algae Chlamydomonas reinhardtii, the plus and minus mating types are controlled by a complex locus, MT, where the dominant MID gene in the MT(-) locus has been shown to be necessary for expression of minus-specific gamete-specific genes in response to nitrogen depletion. We report studies on MID expression patterns during gametogenesis and on a second gene unique to the MT(-) locus, MTD1. Vegetative cells express basal levels of MID. An early activation of MID transcription after nitrogen removal, and its sequence similarity to plant RWP-RK proteins involved in nitrogen-responsive processes, suggest that Mid conformation/activity may be nitrogen sensitive. A second stage of MID upregulation correlates with the acquisition of mating ability in minus gametes. Knockdown of MTD1 by RNAi in minus strains results in a failure to differentiate into gametes of either mating type after nitrogen deprivation. We propose that intermediate Mid levels are sufficient to activate MTD1 transcription and to repress plus gamete-specific genes and that MTD1 expression in turn allows the threshold-level MID expression needed to turn on minus gamete-specific genes. We further propose that an MTD1-equivalent system, utilizing at least one gene product encoded in the MT(+) locus, is operant during plus gametogenesis.

  7. The Ustilago maydis b mating type locus controls hyphal proliferation and expression of secreted virulence factors in planta.

    PubMed

    Wahl, Ramon; Zahiri, Alexander; Kämper, Jörg

    2010-01-01

    Sexual development in fungi is controlled by mating type loci that prevent self-fertilization. In the phytopathogenic fungus Ustilago maydis, the b mating type locus encodes two homeodomain proteins, termed bE and bW. After cell fusion, a heterodimeric bE/bW complex is formed if the proteins are derived from different alleles. The bE/bW complex is required and sufficient to initiate pathogenic development and sexual reproduction; for the stages of pathogenic development succeeding plant penetration, however, its role was unclear. To analyse b function during in planta development, we generated a temperature-sensitive bE(ts) protein by exchange of a single amino acid. bE(ts) strains are stalled in pathogenic development at restrictive temperature in planta, and hyphae develop enlarged, bulbous cells at their tips that contain multiple nuclei, indicating a severe defect in the control and synchronization of cell cycle and cytokinesis. DNA array analysis of bE(ts) mutant strains in planta revealed a b-dependent regulation of genes encoding secreted proteins that were shown to influence fungal virulence. Our data demonstrate that in U. maydis the b heterodimer is not only essential to establish the heterodikaryon after mating of two compatible sporidia and to initiate fungal pathogenicity, but also to sustain in planta proliferation and ensure sexual reproduction.

  8. Cryptococcus neoformans, Cryptococcus gattii: serotypes in Venezuela.

    PubMed

    Pérez, C; Dolande, M; Moya, M; Roselló, A; de Capriles, Claudia R Hartung; Landaeta, M E; Mata-Essayag, S

    2008-09-01

    Cryptococcus neoformans is one of the medically important yeast-like fungi. C. neoformans var. gatti has been made a species: C. gatti. In our country, there are few studies about these two species and their serotypes. The aim of this study was to determine the distribution of C. neoformans and C. gattii, and their serotypes in Venezuelan clinical isolates. One hundred and twenty C. neoformans and 12 C. gattii clinical isolates were identified by L-canavanine, glycine, and bromothymol blue agar media (CGB). These were investigated by agglutination and adsorption studies with anticryptococcal sera, which were produced by rabbit immunization. Of the 132 isolates 59.8% were typed serotype A (C. neoformans), followed by 25.8% serotype D (C. neoformans), 5.3% serotype AD (C. neoformans), and 5.3% were typed serotype C (var. gattii). Additionally 3.8% were serotype B (C. gattii).

  9. A sex recognition glycoprotein is encoded by the plus mating-type gene fus1 of Chlamydomonas reinhardtii.

    PubMed Central

    Ferris, P J; Woessner, J P; Goodenough, U W

    1996-01-01

    Sexual fusion between plus and minus gametes of the unicellular green alga Chlamydomonas reinhardtii entails adhesion between plus-specific and minus-specific "fringe" proteins displayed on the plasma membrane of gametic mating structures. We report the identification of the gene (fus1) encoding the plus fringe glycoprotein, which resides in a unique domain of the mating-type plus (mt+) locus, and which was identified by transposon insertions in three fusion-defective mutant strains. Transformation with fus1+ restores fringe and fusion competence to these mutants and to the pseudo-plus mutant imp11 mt-, defective in minus differentiation. The fus1 gene is remarkable in lacking the codon bias found in all other nuclear genes of C. reinhardtii. Images PMID:8856667

  10. Distribution of Suicin Gene Clusters in Streptococcus suis Serotype 2 Belonging to Sequence Types 25 and 28

    PubMed Central

    Athey, Taryn B. T.; Vaillancourt, Katy; Frenette, Michel; Gottschalk, Marcelo

    2016-01-01

    Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65. The gene cluster encoding suicin 65 was the most prevalent and mainly found among ST25 strains. In contrast, none of the genes related to suicin 90-1330 production were identified in 51 ST25 strains nor in 35/51 ST28 strains. However, the complete suicin 90-1330 gene cluster was found in ten ST28 strains, although some genes in the cluster were truncated in three of these isolates. The vast majority (101/102) of S. suis strains did not possess any of the genes encoding suicin 3908. In conclusion, this study indicates heterogeneous distribution of suicin genes in S. suis. PMID:28078298

  11. Distribution of Suicin Gene Clusters in Streptococcus suis Serotype 2 Belonging to Sequence Types 25 and 28.

    PubMed

    Athey, Taryn B T; Vaillancourt, Katy; Frenette, Michel; Fittipaldi, Nahuel; Gottschalk, Marcelo; Grenier, Daniel

    2016-01-01

    Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65. The gene cluster encoding suicin 65 was the most prevalent and mainly found among ST25 strains. In contrast, none of the genes related to suicin 90-1330 production were identified in 51 ST25 strains nor in 35/51 ST28 strains. However, the complete suicin 90-1330 gene cluster was found in ten ST28 strains, although some genes in the cluster were truncated in three of these isolates. The vast majority (101/102) of S. suis strains did not possess any of the genes encoding suicin 3908. In conclusion, this study indicates heterogeneous distribution of suicin genes in S. suis.

  12. Streptococcus suis, an important pig pathogen and emerging zoonotic agent—an update on the worldwide distribution based on serotyping and sequence typing

    PubMed Central

    Goyette-Desjardins, Guillaume; Auger, Jean-Philippe; Xu, Jianguo; Segura, Mariela; Gottschalk, Marcelo

    2014-01-01

    Streptococcus suis is an important pathogen causing economic problems in the pig industry. Moreover, it is a zoonotic agent causing severe infections to people in close contact with infected pigs or pork-derived products. Although considered sporadic in the past, human S. suis infections have been reported during the last 45 years, with two large outbreaks recorded in China. In fact, the number of reported human cases has significantly increased in recent years. In this review, we present the worldwide distribution of serotypes and sequence types (STs), as determined by multilocus sequence typing, for pigs (between 2002 and 2013) and humans (between 1968 and 2013). The methods employed for S. suis identification and typing, the current epidemiological knowledge regarding serotypes and STs and the zoonotic potential of S. suis are discussed. Increased awareness of S. suis in both human and veterinary diagnostic laboratories and further establishment of typing methods will contribute to our knowledge of this pathogen, especially in regions where complete and/or recent data is lacking. More research is required to understand differences in virulence that occur among S. suis strains and if these differences can be associated with specific serotypes or STs. PMID:26038745

  13. [Mating types in the ciliate Dileptus anser. Inheritance and genetic determination].

    PubMed

    Iudin, A L; Uspenskaia, Z I

    2006-01-01

    Hybridological analysis of mating types (MTs) has been first made for the lower ciliate Dileptus anser. Clones of an initially unknown genotype belonging to three MTs (MT I, MT II and MT III), characteristic of D. anser, were isolated from natural reservoirs and further used for crosses. In one group crosses, synclonal inheritance and typical Mendelian behaviour of the character were observed over sexual generations of ciliates. The results suggest that MTs in D. anser may be directly controlled by a single mat locus with three alleles showing peck-order dominance (mat1 > mat2 > mat3). In other words, cells with mat1/mat1, mat1/mat2 and mat1/mat3 genotypes belong to MT I, those with mat2/mat2 and mat2/mat3, and the mat3/mat3 belong to MT II and MT III, respectively. Sexually mature exconjugant clones stably retain their MTs corresponding to their genotypes on vegetative reproduction. The progeny of other group crosses showed various deviations from typical Mendelian behaviour of the character. In some cases, standard Mendelian ratios were more or less violated. Most typical was instability of differentiation for MT in maturing exconjugant clones. Shortly after their maturation, the majority of clones change their MT, rather frequently more than once, although the finally established MT is stably inherited afterwards, during vegetative reproduction. When unstable, exconjugant clones can successively express two or even three MTs characteristic of this species, including MTs that should not have been expected on the basis of parental genotypes available in a given cross. It looks likely that the mat locus in D. anser is complex and multipotential; it is inherited as a whole providing for expression of any MT characteristic of the species (in this respect bearing similarity with Tetrahymena thermophila). Other mechanisms, epigenetic in particular (Nanney, 1958), determine the final expression of one of the three MT potentialities by a given exconjugant clone. Stable

  14. Selection against spermatozoa with fragmented DNA after postovulatory mating depends on the type of damage

    PubMed Central

    2010-01-01

    Background Before ovulation, sperm-oviduct interaction mechanisms may act as checkpoint for the selection of fertilizing spermatozoa in mammals. Postovulatory mating does not allow the sperm to attach to the oviduct, and spermatozoa may only undergo some selection processes during the transport through the female reproductive tract and/or during the zona pellucida (ZP) binding/penetration. Methods We have induced DNA damage in spermatozoa by two treatments, (a) a scrotal heat treatment (42 degrees C, 30 min) and (b) irradiation with 137Cs gamma-rays (4 Gy, 1.25 Gy/min). The effects of the treatments were analyzed 21-25 days post heat stress or gamma-radiation. Postovulatory females mated either with treated or control males were sacrificed at Day 14 of pregnancy, and numbers of fetuses and resorptions were recorded. Results Both treatments decreased significantly implantation rates however, the proportion of fetuses/resorptions was only reduced in those females mated to males exposed to radiation, indicating a selection favoring fertilization of sperm with unfragmented DNA on the heat treatment group. To determine if DNA integrity is one of the keys of spermatozoa selection after postovulatory mating, we analyzed sperm DNA fragmentation by COMET assay in: a) sperm recovered from mouse epididymides; b) sperm recovered from three different regions of female uterine horns after mating; and c) sperm attached to the ZP after in vitro fertilization (IVF). Similar results were found for control and both treatments, COMET values decreased significantly during the transit from the uterine section close to the uterotubal junction to the oviduct, and in the spermatozoa attached to ZP. However, fertilization by IVF and intracytoplasmatic sperm injection (ICSI) showed that during sperm ZP-penetration, a stringent selection against fragmented-DNA sperm is carried out when the damage was induced by heat stress, but not when DNA fragmentation was induced by radiation. Conclusion

  15. Development of an allele-specific PCR assay for simultaneous sero-typing of avian pathogenic Escherichia coli predominant O1, O2, O18 and O78 strains.

    PubMed

    Wang, Shaohui; Meng, Qingmei; Dai, Jianjun; Han, Xiangan; Han, Yue; Ding, Chan; Liu, Haiwen; Yu, Shengqing

    2014-01-01

    Systemic infections by avian pathogenic Escherichia coli (APEC) are economically devastating to poultry industries worldwide. E. coli strains belonging to serotypes O1, O2, O18 and O78 are preferentially associated with avian colibacillosis. The rfb gene cluster controlling O antigen synthesis is usually various among different E. coli serotypes. In present study, the rfb gene clusters of E. coli serotypes O1, O2, O18 and O78 were characterized and compared. Based on the serotype-specific genes in rfb gene cluster, an allele-specific polymerase chain reaction (PCR) assay was developed. This PCR assay was highly specific and reliable for sero-typing of APEC O1, O2, O18 and O78 strains. The sensitivity of the assay was determined as 10 pg DNA or 10 colony forming units (CFUs) bacteria for serotypes O2 and O18 strains, and 500 pg DNA or 1,000 CFUs bacteria for serotypes O1 and O78 strains. Using this PCR system, APEC isolates and the infected tissue samples were categorized successfully. Furthermore, it was able to differentiate the serotypes for the samples with multi-agglutination in the traditional serum agglutination assay. Therefore, the allele-specific PCR is more simple, rapid and accurate assay for APEC diagnosis, epidemiologic study and vaccine development.

  16. BOTH MAT1-1 AND MAT1-2 MATING TYPES OF MYCOSPHAERELLA GRAMINICOLA OCCUR AT EQUAL FREQUENCIES IN ALGERIA.

    PubMed

    Allioui, N; Siah, A; Brinis, L; Reignault, Ph; Halama, P

    2014-01-01

    Septoria tritici blotch caused by Mycosphaerella graminicola is currently the most devastating disease on wheat crops worldwide. Mycosphaerella graminicola sexual reproduction involves two mating type idiomorphs that were previously studied in several areas around the world, but not in Algeria so far. The objective of this study was thus to determine the frequencies and distribution of M. graminicola mating types in this country. One hundred and twenty monoconidial isolates of this fungus (60 from bread wheat and 60 from durum wheat) were collected during the 2012 growing season from five distinct geographical locations in Algeria. The mating type of each isolate was identified using a multiplex PCR that amplifies either MAT1-1 or MAT1-2 fragment from mating type loci. Both idiomorphs were found at equal frequencies according to the chi-square test at the whole country level (46% MAT1-1 and 54% MAT1-2) and in each of the sampled locations. The two mating types were also detected at equal frequencies on both host species (47% MAT1-1 vs 53% MAT1-2 on bread wheat and 45% MAT1-1 vs 55% MAT1-2 on durum wheat). Our study showed that the two mating types of M. graminicola occur at equal proportions in Algeria and suggests a strong potential for sexual reproduction of the pathogen in this country that may eventually lead to either adaptation to local conditions, plant resistance overcoming or the emergence of resistance to fungicides.

  17. Aggressive and mating behaviors in two types of sex reversed mice: XY females and XX males.

    PubMed

    Canastar, Andrew; Maxson, Stephen C; Bishop, Colin E

    2008-02-01

    Aggressive and mating behaviors were assessed in XX females, XY females, and XY males of the C57BL/6/J/Ei ("C57BL/6" or "B6") strain of mouse. The Y chromosome of the XY females derives from Mus domesticus poschiavinus and the Y chromosome of the XY males derives from Mus musculus. The poschiavinus Y in the C57BL/6 background results in XY mice with either ovaries or ovotestes. Only those with ovaries were tested. These XY females appear to be endocrinologically identical to XX females. Aggressive and mating behaviors were also tested in XX males and XY males of the FVB/NtacfBR Odsex ("FVB") strain of mouse. The XX males have a transgene inserted 1 Mb upstream of the SOX9 gene, resulting in gonadal differentiation as a testis in the absence of a Y chromosome. C57BL/6 mice were tested for aggression in an instigated resident intruder paradigm and FVB/NtacfBR Odsex mice were tested for aggression in a neutral cage paradigm. Mice of both strains were tested with opponents of the same sex chromosome complement and gonadal sex. On the C57BL/6 background, the XY males were more aggressive than the XY and XX females, but there was no significant difference between the XX and XY females in aggression. On the FVB background, the XY and XX males were equally aggressive. Mice from both C57BL/6 and FVB backgrounds were tested for mating behaviors with females in hormonal estrus. On the C57BL/6 background, the XY males mounted more than the XY females, but there was no significant difference between the XY and XX females in mounting. On the FVB background, mounting, intromissions, and ejaculations were the same in XY and XX males. The implications of these findings for the effect of sex chromosome complement on sex differences in aggression and mating in mice are discussed.

  18. Characterization of Chinese Haemophilus parasuis Isolates by Traditional Serotyping and Molecular Serotyping Methods

    PubMed Central

    Ma, Lina; Wang, Liyan; Chu, Yuefeng; Li, Xuerui; Cui, Yujun; Chen, Shengli; Zhou, Jianhua; Li, Chunling; Lu, Zhongxin; Liu, Jixing; Liu, Yongsheng

    2016-01-01

    Haemophilus parasuis is classified mainly through serotyping, but traditional serotyping always yields non-typable (NT) strains and unreliable results via cross-reactions. Here, we surveyed the serotype prevalence of Chinese H. parasuis isolates using traditional serotyping (gel immuno-diffusion test, GID) and molecular serotyping (multiplex PCR, mPCR). We also investigated why discrepant results between these methods were obtained, and investigated mPCR failure through whole-genome sequencing. Of the 100 isolate tested, 73 (73%) and 93 (93%) were serotyped by the GID test and mPCR, respectively, with a concordance rate of 66% (66/100). Additionally, mPCR reduced the number of NT isolates from 27 (27%) for the GID testing, to seven (7%). Eleven isolates were sequenced, including nine serotype-discrepant isolates from mPCR and GID typing (excluding strains that were NT by GID only) and two NT isolates from both methods, and their in silico serotypes were obtained from genome sequencing based on their capsule loci. The mPCR results were supported by the in silico serotyping of the seven serotype-discrepant isolates. The discrepant results and NT isolates determined by mPCR were attributed to deletions and unknown sequences in the serotype-specific region of each capsule locus. Compared with previous investigations, this study found a similar predominant serotype profile, but a different prevalence frequency for H. parasuis, and the five most prevalent serotypes or strain groups were serotypes 5, 4, NT, 7 and 13 for mPCR, and serotypes 5, NT, 4, 7 and 13/10/14 for GID. Additionally, serotype 7 was recognized as a principal serotype in this work. PMID:28005999

  19. The fission yeast homologue of CENP-B, Abp1, regulates directionality of mating-type switching

    PubMed Central

    Aguilar-Arnal, Lorena; Marsellach, Francesc-Xavier; Azorín, Fernando

    2008-01-01

    In fission yeast, mating-type switching involves replacing genetic information contained at the expressed mat1 locus by that of either the mat2P or mat3M donor loci. Donor selection is nonrandom, as mat1P cells preferentially use mat3M for switching, whereas mat1M cells use mat2P. Switching directionality is determined by the cell-type-specific distribution of the Swi2–Swi5 complex that, in mat1P cells, localises to mat3M and, only in mat1M cells, spreads to mat2P in a heterochromatin-dependent manner. Mechanisms regulating spreading of Swi2–Swi5 across heterochromatin are not fully understood. Here, we show that the fission yeast homologue of CENP-B, Abp1, binds to the silent domain of the mating-type locus and regulates directionality of switching. Deletion of abp1 prevents utilisation of mat2P, as when heterochromatin is disrupted and spreading of Swi2–Swi5 is impaired. Our results show that, indeed, deletion of abp1 abolishes spreading of Swi2–Swi5 to mat2P. However, in abp1Δ cells, heterochromatin organisation at the mating-type locus is preserved, indicating that Abp1 is actually required for efficient spreading of Swi2–Swi5 through heterochromatin. Cbh1 and Cbh2, which are also homologous to CENP-B, have only a minor contribution to the regulation of directionality of switching, which is in contrast with the strong effects observed for Abp1. PMID:18354497

  20. The fission yeast homologue of CENP-B, Abp1, regulates directionality of mating-type switching.

    PubMed

    Aguilar-Arnal, Lorena; Marsellach, Francesc-Xavier; Azorín, Fernando

    2008-04-09

    In fission yeast, mating-type switching involves replacing genetic information contained at the expressed mat1 locus by that of either the mat2P or mat3M donor loci. Donor selection is nonrandom, as mat1P cells preferentially use mat3M for switching, whereas mat1M cells use mat2P. Switching directionality is determined by the cell-type-specific distribution of the Swi2-Swi5 complex that, in mat1P cells, localises to mat3M and, only in mat1M cells, spreads to mat2P in a heterochromatin-dependent manner. Mechanisms regulating spreading of Swi2-Swi5 across heterochromatin are not fully understood. Here, we show that the fission yeast homologue of CENP-B, Abp1, binds to the silent domain of the mating-type locus and regulates directionality of switching. Deletion of abp1 prevents utilisation of mat2P, as when heterochromatin is disrupted and spreading of Swi2-Swi5 is impaired. Our results show that, indeed, deletion of abp1 abolishes spreading of Swi2-Swi5 to mat2P. However, in abp1Delta cells, heterochromatin organisation at the mating-type locus is preserved, indicating that Abp1 is actually required for efficient spreading of Swi2-Swi5 through heterochromatin. Cbh1 and Cbh2, which are also homologous to CENP-B, have only a minor contribution to the regulation of directionality of switching, which is in contrast with the strong effects observed for Abp1.

  1. Yerba Mate

    MedlinePlus

    ... high cholesterol who are also taking statin drugs. Obesity. Early research shows that taking yerba mate by ... with yerba mate.MajorDo not take this combination.Antibiotics (Quinolone antibiotics)The body breaks down caffeine to ...

  2. NGSCheckMate: software for validating sample identity in next-generation sequencing studies within and across data types.

    PubMed

    Lee, Sejoon; Lee, Soohyun; Ouellette, Scott; Park, Woong-Yang; Lee, Eunjung A; Park, Peter J

    2017-03-23

    In many next-generation sequencing (NGS) studies, multiple samples or data types are profiled for each individual. An important quality control (QC) step in these studies is to ensure that datasets from the same subject are properly paired. Given the heterogeneity of data types, file types and sequencing depths in a multi-dimensional study, a robust program that provides a standardized metric for genotype comparisons would be useful. Here, we describe NGSCheckMate, a user-friendly software package for verifying sample identities from FASTQ, BAM or VCF files. This tool uses a model-based method to compare allele read fractions at known single-nucleotide polymorphisms, considering depth-dependent behavior of similarity metrics for identical and unrelated samples. Our evaluation shows that NGSCheckMate is effective for a variety of data types, including exome sequencing, whole-genome sequencing, RNA-seq, ChIP-seq, targeted sequencing and single-cell whole-genome sequencing, with a minimal requirement for sequencing depth (>0.5X). An alignment-free module can be run directly on FASTQ files for a quick initial check. We recommend using this software as a QC step in NGS studies.

  3. Serotyping and multilocus sequence typing of Streptococcus pneumoniae isolates from the blood and posterior nares of Japanese children prior to the introduction of 7-valent pneumococcal conjugate vaccine.

    PubMed

    Oishi, Tomohiro; Wada, Akihito; Chang, Bin; Toyabe, Shinichi; Uchiyama, Makoto

    2011-01-01

    In Japan, the 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. To assess the effects of PCV7 on invasive pneumococcal infection in children, a population-based prospective survey has been conducted in 10 prefectures. As a part of the study, blood and nasopharyngeal isolates from children admitted to the Shibata Hospital, Niigata Prefecture, were analyzed for determining the serotypes, their susceptibilities to antimicrobial agents, and multilocus sequence types. Sixteen blood isolates were obtained from October 2007 to December 2009. Sixty-three nasopharyngeal isolates were obtained from the posterior nares of 118 children with pneumonia from April to September 2008. The coverage rates of the blood and nasopharyngeal isolates for PCV7 were 81.3% and 57.1%, respectively. Although none of these children had received PCV7, serotype 19A isolates were recovered from 12.5% (2/16) of the blood samples and 12.7% (8/63) of the nasopharyngeal samples. The sequence type of a nasopharyngeal isolate of serotype 19A was ST320, and the minimum inhibitory concentration of penicillin G was 4 μg/mL. In addition to the continuous prospective survey of pneumococcal infection, early introduction of the 13-valent conjugate vaccine, in which the 19A conjugate is included, will be necessary in Japan.

  4. Simultaneously Typing Nine Serotypes of Enteroviruses Associated with Hand, Foot, and Mouth Disease by a GeXP Analyzer-Based Multiplex Reverse Transcription-PCR Assay

    PubMed Central

    Hu, Xiumei; Zhang, Yong; Zhou, Xiaomian; Xu, Banglao; Yang, Mengjie; Wang, Miao; Zhang, Chen; Li, Jin; Bai, Ruyin

    2012-01-01

    Hand, foot, and mouth disease (HFMD) is a contagious enteroviral disease occurring primarily in young children and caused by enterovirus 71 (EV71), coxsackievirus A16 (CVA16), and other serotypes of coxsackievirus and echovirus. In this study, a GeXP analyzer-based multiplex reverse transcription (RT)-PCR assay (GeXP assay) consisting of chimeric primer-based PCR amplification with fluorescent labeling and capillary electrophoresis separation was developed to simultaneously identify nine serotypes of enteroviruses associated with HFMD in China, including EV71, CVA16, CVA4, -5, -9, and -10, and CVB1, -3, and -5. The RNAs extracted from cell cultures of viral isolates and synthetic RNAs via in vitro transcription were used to analyze the specificity and sensitivity of the assay. The GeXP assay detected as little as 0.03 tissue culture infective dose (TCID50) of EV71 and CVA16, 10 copies of panenterovirus, EV71, CVA16, CVB1, and CVB5, and 100 copies of 10 (including panenterovirus) premixed RNA templates. A total of 180 stool specimens collected from HFMD patients and persons suspected of having HFMD were used to evaluate the clinical performance of this assay. In comparison with the results of conventional methods, the sensitivities of the GeXP assay for detection of panenterovirus, EV71, and CVA16 were 98.79% (163/165), 91.67% (44/48), and 91.67% (33/36), respectively, and the specificities were 80.00% (12/15), 98.48% (130/132), and 100% (144/144), respectively. The concordance of typing seven other serotypes of enteroviruses with the results of conventional methods was 92.59% (25/27). In conclusion, the GeXP assay is a rapid, cost-effective, and high-throughput method for typing nine serotypes of HFMD-associated enteroviruses. PMID:22116146

  5. Simultaneously typing nine serotypes of enteroviruses associated with hand, foot, and mouth disease by a GeXP analyzer-based multiplex reverse transcription-PCR assay.

    PubMed

    Hu, Xiumei; Zhang, Yong; Zhou, Xiaomian; Xu, Banglao; Yang, Mengjie; Wang, Miao; Zhang, Chen; Li, Jin; Bai, Ruyin; Xu, Wenbo; Ma, Xuejun

    2012-02-01

    Hand, foot, and mouth disease (HFMD) is a contagious enteroviral disease occurring primarily in young children and caused by enterovirus 71 (EV71), coxsackievirus A16 (CVA16), and other serotypes of coxsackievirus and echovirus. In this study, a GeXP analyzer-based multiplex reverse transcription (RT)-PCR assay (GeXP assay) consisting of chimeric primer-based PCR amplification with fluorescent labeling and capillary electrophoresis separation was developed to simultaneously identify nine serotypes of enteroviruses associated with HFMD in China, including EV71, CVA16, CVA4, -5, -9, and -10, and CVB1, -3, and -5. The RNAs extracted from cell cultures of viral isolates and synthetic RNAs via in vitro transcription were used to analyze the specificity and sensitivity of the assay. The GeXP assay detected as little as 0.03 tissue culture infective dose (TCID(50)) of EV71 and CVA16, 10 copies of panenterovirus, EV71, CVA16, CVB1, and CVB5, and 100 copies of 10 (including panenterovirus) premixed RNA templates. A total of 180 stool specimens collected from HFMD patients and persons suspected of having HFMD were used to evaluate the clinical performance of this assay. In comparison with the results of conventional methods, the sensitivities of the GeXP assay for detection of panenterovirus, EV71, and CVA16 were 98.79% (163/165), 91.67% (44/48), and 91.67% (33/36), respectively, and the specificities were 80.00% (12/15), 98.48% (130/132), and 100% (144/144), respectively. The concordance of typing seven other serotypes of enteroviruses with the results of conventional methods was 92.59% (25/27). In conclusion, the GeXP assay is a rapid, cost-effective, and high-throughput method for typing nine serotypes of HFMD-associated enteroviruses.

  6. Assortative mating in animals.

    PubMed

    Jiang, Yuexin; Bolnick, Daniel I; Kirkpatrick, Mark

    2013-06-01

    Assortative mating occurs when there is a correlation (positive or negative) between male and female phenotypes or genotypes across mated pairs. To determine the typical strength and direction of assortative mating in animals, we carried out a meta-analysis of published measures of assortative mating for a variety of phenotypic and genotypic traits in a diverse set of animal taxa. We focused on the strength of assortment within populations, excluding reproductively isolated populations and species. We collected 1,116 published correlations between mated pairs from 254 species (360 unique species-trait combinations) in five phyla. The mean correlation between mates was 0.28, showing an overall tendency toward positive assortative mating within populations. Although 19% of the correlations were negative, simulations suggest that these could represent type I error and that negative assortative mating may be rare. We also find significant differences in the strength of assortment among major taxonomic groups and among trait categories. We discuss various possible reasons for the evolution of assortative mating and its implications for speciation.

  7. Association of type- and group-specific antigens with the cell wall of serotype III group B streptococcus.

    PubMed Central

    Doran, T I; Mattingly, S J

    1982-01-01

    The type-specific antigens (TSA) of group B streptococcus (GBS) represent the primary virulence factors for these organisms, yet little is known about their relationship to the cell surface of GBS. Crude cell walls of serotype III GBS strain 110 were purified by extraction with sodium dodecyl sulfate, LiCl, and urea, which removed essentially all of the protein associated with the cell wall as determined by amino acid analysis. Only those amino acids found in peptidoglycan were present, which included alanine, lysine, and glutamate (3.5:1:1 molar ratio). In contrast, these procedures resulted in the release of only 4.6% of the wall-associated TSA, indicating that protein was not the primary means by which TSA was bound to the cell surface. Mutanolysin (20 micrograms/ml) treatment of purified cell walls resulted in the release of 95% of the wall-associated TSA. The covalent association of TSA, the group B polysaccharide, and the peptidoglycan was demonstrated by the presence of N-acetylmuramic acid, rhamnose, alanine, glutamate, and lysine in mutanolysin-extracted TSA material purified by DEAE-Sephacel anion exchange and Sepharose 4B gel chromatography. Chemical analysis of purified cell walls revealed that group B antigen and peptidoglycan comprised 37.4 and 36.5%, respectively, whereas TSA accounted for 22.1 to 24.5% of the weight of the purified walls. Of the total 283.5 mg of TSA produced per 10-liter culture of GBS strain 110, 8.4% was released into the supernatant fluid. The remainder (249 mg) comprised the cell wall antigen. As described above, 4.6% of the cell wall antigen was extractable by nonenzymatic methods, which represented 3.8% of the total TSA, whereas 87.8% of the total TSA produced appeared to be covalently attached to the cell wall. PMID:7047392

  8. Mating-Type Effect on CIS Mutations Leading to Constitutivity of Ornithine Transaminase in Diploid Cells of SACCHAROMYCES CEREVISIAE

    PubMed Central

    Deschamps, Jacqueline; Wiame, Jean-Marie

    1979-01-01

    Cis-acting regulatory mutations have been isolated that affect L-ornithine transaminase (OTAse), an enzyme catalyzing the second step of arginine breakdown in yeast. These mutations lead to constitutive synthesis of OTAse at various levels. Two different types of mutations have been recovered, both of which are tightly linked to the structural gene (cargB) for this enzyme. One type behaves as a classical operator-constitutive mutation similar to the cargB+O-—1 mutation previously described (Dubois et al. 1978).—The second type is peculiar in two respects: the higher level of constitutive OTAse synthesis and the expression of constitutivity in diploid cells. These mutations are designated cargB+Oh. They behave as usual operator-constitutive mutations in diploid strains homozygous for mating type (a/a or α/α), but the constitutivity is strongly reduced in a/α diploid cells. PMID:395019

  9. Mating types in yeast, vomeronasal organ in rodents, homosexuality in humans: does a guiding thread exist?

    PubMed

    Oliva, Daniele

    2002-08-01

    Pheromones and their receptors are the molecules used by very different organisms in order to join two haploid cells. It happens evidently in yeast, since the two blending haploid cells are also the two mating organisms, whereas in rodents pheromone receptors are the triggers of the vomeronasal system which, supervising sexual behaviors, is responsible for copulation and therefore for fertilization. The debate is still open about the real significance of pheromones in humans but a working vomeronasal organ, able to recognize pheromones of the same sex, could be the simplest biological explanation of homosexuality. This hypothesis is discussed and connected with some well known experimental data.

  10. Typing and characterization of ColE1-like plasmids conferring kanamycin resistance in Salmonella enterica serotypes

    USDA-ARS?s Scientific Manuscript database

    Background: Multi-antibiotic resistant Salmonella enterica serotypes are increasing in prevalence and concern in human and animal health. Many strains carry resistance determinants on plasmids; current practices focus heavily on large plasmids and the role small plasmids play in resistance gene tra...

  11. Organization and evolution of mating-type genes in three Stagonosporopsis species causing gummy stem blight of cucurbits and leaf spot and dry rot of papaya.

    PubMed

    Li, Hao-Xi; Gottilla, Thomas M; Brewer, Marin Talbot

    2017-10-01

    Population divergence and speciation of closely related lineages can result from reproductive differences leading to genetic isolation. An increasing number of fungal diseases of plants and animals have been determined to be caused by morphologically indistinguishable species that are genetically distinct, thereby representing cryptic species. We were interested in identifying if mating systems among three Stagonosporopsis species (S. citrulli, S. cucurbitacearum, and S. caricae) causing gummy stem blight (GSB) of cucurbits or leaf spot and dry rot of papaya differed, possibly underlying species divergence. Additionally, we were interested in identifying evolutionary pressures acting on the genes controlling mating in these fungi. The mating-type loci (MAT1) of three isolates from each of the three species were identified in draft genome sequences. For the three species, MAT1 was structurally identical and contained both mating-type genes necessary for sexual reproduction, which suggests that all three species are homothallic. However, both MAT1-1-1 and MAT1-2-1 were divergent among species showing rapid evolution with a much greater number of amino acid-changing substitutions detected for the reproductive genes compared with genes flanking MAT1. Positive selection was detected in MAT1-2-1, especially in the highly conserved high mobility group (MATA_HMG-box) domain. Thus, the mating-type genes are rapidly evolving in GSB fungi, but a difference in mating systems among the three species does not underlie their divergence. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  12. Only one of the two type VI secretion systems encoded in the Salmonella enterica serotype Dublin genome is involved in colonization of the avian and murine hosts

    PubMed Central

    2014-01-01

    The type VI secretion system (T6SS) is a virulence factor for many Gram-negative bacteria. Salmonella genus harbors five phylogenetically distinct T6SS loci encoded in Salmonella Pathogenicity Islands (SPIs) SPI-6, SPI-19, SPI-20, SPI-21 and SPI-22, which are differentially distributed among serotypes. The T6SSs encoded in SPI-6 and SPI-19 contribute to pathogenesis of serotypes Typhimurium and Gallinarum in mice and chickens, respectively. Salmonella Dublin is a pathogen restricted to cattle where it causes a systemic disease. Also, it can colonize other hosts such as chickens and mice, which can act as reservoirs of this serotype. Salmonella Dublin harbors the genes for both T6SSSPI-6 and T6SSSPI-19. This study has determined the contribution of T6SSSPI-6 and T6SSSPI-19 to host-colonization by Salmonella Dublin using avian and murine models of infection. Competitive index experiments showed that, a mutant strain lacking both T6SSs (∆T6SSSPI-6/∆T6SSSPI-19) presents a strong colonization defect in cecum of chickens, similar to the defect observed for the ∆T6SSSPI-6 mutant, suggesting that this serotype requires a functional T6SSSPI-6 for efficient colonization of the avian gastrointestinal tract. Colonization of mice was also defective, although to a lesser extent than in chickens. In contrast, the T6SSSPI-19 was not necessary for colonization of either chickens or mice. Transfer of T6SSSPI-6, but not T6SSSPI-19, restored the ability of the double mutant to colonize both animal hosts. Our data indicate that Salmonella Dublin requires only the T6SSSPI-6 for efficient colonization of mice and chickens, and that the T6SSSPI-6 and T6SSSPI-19 are not functionally redundant. PMID:24405577

  13. The mating-type locus B alpha 1 of Schizophyllum commune contains a pheromone receptor gene and putative pheromone genes.

    PubMed Central

    Wendland, J; Vaillancourt, L J; Hegner, J; Lengeler, K B; Laddison, K J; Specht, C A; Raper, C A; Kothe, E

    1995-01-01

    Analysis of the multispecific B alpha mating-type locus of Schizophyllum commune provided evidence that pheromones and pheromone receptors govern recognition of self versus non-self and sexual development in this homobasidiomycetous fungus. Four subclones of an 8.2 kb genomic fragment carrying B alpha 1 specificity induced B-regulated sexual morphogenesis when introduced into a strain with one of the eight compatible B alpha specificities that are known to exist in nature. One of these clones, which activated all other B alpha specificities, contains a gene termed bar1. The predicted protein product of bar1, as well as that of bar2, a homologous gene isolated from a B alpha 2 strain, has significant homology to known fungal pheromone receptor proteins in the rhodopsin-like superfamily of G protein-linked receptors. The other three active B alpha 1 clones were subcloned further to identify the minimal active element in each clone. Every active subclone contains a putative pheromone gene ending in a signal for possible isoprenylation. A message of approximately 600 bp was observed for one of these genes, bap1(1). This paper presents the first evidence for a system of multiple pheromones and pheromone receptors as a basis for multispecific mating types in a fungus. Images PMID:7489716

  14. Efficient production of a ring derivative of chromosome III by the mating-type switching mechanism in Saccharomyces cerevisiae.

    PubMed Central

    Klar, A J; Strathern, J N; Hicks, J B; Prudente, D

    1983-01-01

    The mating-type switches in the yeast Saccharomyces cerevisiae occur by unidirectional transposition of replicas of unexpressed genetic information, residing at HML or HMR, into the mating-type locus (MAT). The source loci, HML and HMR, remain unchanged. Interestingly, when the HM cassettes are expressed, as in marl strains, the HML and HMR cassettes can also efficiently switch, apparently by obtaining genetic information from either of the other two cassettes (Klar et al., Cell 25:517-524, 1981). We have isolated a novel chromosome III rearrangement in heterothallic (marl ho) strains, which is also produced efficiently in marl HO cells, presumably the consequence of a recombination event between HML and HMR. The fusion results in the loss of sequences which are located distal to HML and to HMR and produces a ring derivative of chromosome III. Cells containing such a ring chromosome are viable as haploids; apparently, no essential loci are located distal to the HM loci. The fusion cassette behaves as a standard HM locus with respect to both regulation by the MAR/SIR control and its role in switching MAT. Images PMID:6346056

  15. Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma

    PubMed Central

    Corcoran, Pádraic; Anderson, Jennifer L.; Jacobson, David J.; Sun, Yu; Ni, Peixiang; Lascoux, Martin; Johannesson, Hanna

    2016-01-01

    Genome evolution is driven by a complex interplay of factors, including selection, recombination, and introgression. The regions determining sexual identity are particularly dynamic parts of eukaryotic genomes that are prone to molecular degeneration associated with suppressed recombination. In the fungus Neurospora tetrasperma, it has been proposed that this molecular degeneration is counteracted by the introgression of nondegenerated DNA from closely related species. In this study, we used comparative and population genomic analyses of 92 genomes from eight phylogenetically and reproductively isolated lineages of N. tetrasperma, and its three closest relatives, to investigate the factors shaping the evolutionary history of the genomes. We found that suppressed recombination extends across at least 6 Mbp (∼63%) of the mating-type (mat) chromosome in N. tetrasperma and is associated with decreased genetic diversity, which is likely the result primarily of selection at linked sites. Furthermore, analyses of molecular evolution revealed an increased mutational load in this region, relative to recombining regions. However, comparative genomic and phylogenetic analyses indicate that the mat chromosomes are temporarily regenerated via introgression from sister species; six of eight lineages show introgression into one of their mat chromosomes, with multiple Neurospora species acting as donors. The introgressed tracts have been fixed within lineages, suggesting that they confer an adaptive advantage in natural populations, and our analyses support the presence of selective sweeps in at least one lineage. Thus, these data strongly support the previously hypothesized role of introgression as a mechanism for the maintenance of mating-type determining chromosomal regions. PMID:26893460

  16. Genetic Variation and Its Reflection on Posttranslational Modifications in Frequency Clock and Mating Type a-1 Proteins in Sordaria fimicola

    PubMed Central

    Arif, Rabia; Akram, Faiza; Jamil, Tazeen; Lee, Siu Fai

    2017-01-01

    Posttranslational modifications (PTMs) occur in all essential proteins taking command of their functions. There are many domains inside proteins where modifications take place on side-chains of amino acids through various enzymes to generate different species of proteins. In this manuscript we have, for the first time, predicted posttranslational modifications of frequency clock and mating type a-1 proteins in Sordaria fimicola collected from different sites to see the effect of environment on proteins or various amino acids pickings and their ultimate impact on consensus sequences present in mating type proteins using bioinformatics tools. Furthermore, we have also measured and walked through genomic DNA of various Sordaria strains to determine genetic diversity by genotyping the short sequence repeats (SSRs) of wild strains of S. fimicola collected from contrasting environments of two opposing slopes (harsh and xeric south facing slope and mild north facing slope) of Evolution Canyon (EC), Israel. Based on the whole genome sequence of S. macrospora, we targeted 20 genomic regions in S. fimicola which contain short sequence repeats (SSRs). Our data revealed genetic variations in strains from south facing slope and these findings assist in the hypothesis that genetic variations caused by stressful environments lead to evolution. PMID:28717646

  17. Characterization of two genes required for the position-effect control of yeast mating-type genes.

    PubMed Central

    Shore, D; Squire, M; Nasmyth, K A

    1984-01-01

    The mating type of haploid yeast (a or alpha) is determined by information present at the MAT locus. Identical copies of a and alpha information are present at distal loci (HMR and HML), but transcription of these copies is repressed by the action, in trans, of four unlinked genes called SIR (silent information regulator). Repression by SIR also requires, in cis, DNA sequences called E which are found to the left of HML and HMR (but not MAT) and are greater than 1 kb from the mating-type gene promoters. SIR control can act on other promoters when they are brought near the E sequence, and thus the SIR gene products act in some general manner to repress transcription. We have determined the DNA sequence of two fragments which complement mutations in the SIR2 and SIR3 genes and show that these contain the structural genes by mapping the cloned sequences onto the yeast chromosome. The SIR2 and SIR3 coding sequences were identified by constructing gene disruptions and using these mutations to replace the normal chromosomal copies. Such null mutants of both SIR2 and SIR3 are defective in the position-effect control of the silent loci but have no other detectable phenotype. We have mapped the 5' and 3' ends of the SIR2 and SIR3 mRNAs and show that their level is unaffected by mutations in any of the four known SIR complementation groups. Images Fig. 2. Fig. 3. Fig. 4. PMID:6098447

  18. Genetic Variation and Its Reflection on Posttranslational Modifications in Frequency Clock and Mating Type a-1 Proteins in Sordaria fimicola.

    PubMed

    Arif, Rabia; Akram, Faiza; Jamil, Tazeen; Mukhtar, Hamid; Lee, Siu Fai; Saleem, Muhammad

    2017-01-01

    Posttranslational modifications (PTMs) occur in all essential proteins taking command of their functions. There are many domains inside proteins where modifications take place on side-chains of amino acids through various enzymes to generate different species of proteins. In this manuscript we have, for the first time, predicted posttranslational modifications of frequency clock and mating type a-1 proteins in Sordaria fimicola collected from different sites to see the effect of environment on proteins or various amino acids pickings and their ultimate impact on consensus sequences present in mating type proteins using bioinformatics tools. Furthermore, we have also measured and walked through genomic DNA of various Sordaria strains to determine genetic diversity by genotyping the short sequence repeats (SSRs) of wild strains of S. fimicola collected from contrasting environments of two opposing slopes (harsh and xeric south facing slope and mild north facing slope) of Evolution Canyon (EC), Israel. Based on the whole genome sequence of S. macrospora, we targeted 20 genomic regions in S. fimicola which contain short sequence repeats (SSRs). Our data revealed genetic variations in strains from south facing slope and these findings assist in the hypothesis that genetic variations caused by stressful environments lead to evolution.

  19. Sexual reproduction and mating-type-mediated strain development in the penicillin-producing fungus Penicillium chrysogenum.

    PubMed

    Böhm, Julia; Hoff, Birgit; O'Gorman, Céline M; Wolfers, Simon; Klix, Volker; Binger, Danielle; Zadra, Ivo; Kürnsteiner, Hubert; Pöggeler, Stefanie; Dyer, Paul S; Kück, Ulrich

    2013-01-22

    Penicillium chrysogenum is a filamentous fungus of major medical and historical importance, being the original and present-day industrial source of the antibiotic penicillin. The species has been considered asexual for more than 100 y, and despite concerted efforts, it has not been possible to induce sexual reproduction, which has prevented sexual crosses being used for strain improvement. However, using knowledge of mating-type (MAT) gene organization, we now describe conditions under which a sexual cycle can be induced leading to production of meiotic ascospores. Evidence of recombination was obtained using both molecular and phenotypic markers. The identified heterothallic sexual cycle was used for strain development purposes, generating offspring with novel combinations of traits relevant to penicillin production. Furthermore, the MAT1-1-1 mating-type gene, known primarily for a role in governing sexual identity, was also found to control transcription of a wide range of genes with biotechnological relevance including those regulating penicillin production, hyphal morphology, and conidial formation. These discoveries of a sexual cycle and MAT gene function are likely to be of broad relevance for manipulation of other asexual fungi of economic importance.

  20. Antiviral activity of Basidiomycete mycelia against influenza type A (serotype H1N1) and herpes simplex virus type 2 in cell culture.

    PubMed

    Krupodorova, Tetiana; Rybalko, Svetlana; Barshteyn, Victor

    2014-10-01

    In this study, we investigated the in vitro antiviral activity of the mycelia of higher mushrooms against influenza virus type A (serotype H1N1) and herpes simplex virus type 2 (HSV-2), strain BH. All 10 investigated mushroom species inhibited the reproduction of influenza virus strain A/FM/1/47 (H1N1) in MDCK cells reducing the infectious titer by 2.0-6.0 lg ID50. Four species, Pleurotus ostreatus, Fomes fomentarius, Auriporia aurea, and Trametes versicolor, were also determined to be effective against HSV-2 strain BH in RK-13 cells, with similar levels of inhibition as for influenza. For some of the investigated mushroom species-Pleurotus eryngii, Lyophyllum shimeji, and Flammulina velutipes-this is the first report of an anti-influenza effect. This study also reports the first data on the medicinal properties of A. aurea, including anti-influenza and antiherpetic activities. T. versicolor 353 mycelium was found to have a high therapeutic index (324.67), and may be a promising material for the pharmaceutical industry as an anti-influenza and antiherpetic agent with low toxicity. Mycelia with antiviral activity were obtained in our investigation by bioconversion of agricultural wastes (amaranth flour after CO2 extraction), which would reduce the cost of the final product and solve some ecological problems.

  1. Mutations in rik1, clr2, clr3 and clr4 genes asymmetrically derepress the silent mating-type loci in fission yeast.

    PubMed

    Ekwall, K; Ruusala, T

    1994-01-01

    In Schizosaccharomyces pombe the mating-type information is stored at two transcriptionally silent loci (mat2 and mat3). The region between these sites (K region) is inert for meiotic crossing over. The mating-type genes (M or P) are expressed only when present at a third, active locus (mat1). We have earlier shown that the positional regulation of P genes is based on repression at the silent site, caused by elements in the flanking DNA sequences. In this study we have mutagenized a sterile mat1 deleted strain and selected for cells that are able to conjugate. Recessive mutations of this type should define genes encoding trans-acting factors involved in repression of the silent mating-type loci. Before this work mutations in two genes, clr1 and swi6, had been shown to allow both expression of the silent loci and recombination in the K region. The sensitivity of the present selection is demonstrated by the isolation of new mutations that derepress one or both of the silent loci (M-mating or bi-mating). The frequency of M-mating mutants was almost two orders of magnitude higher than that of bi-mating mutants and in all mutants analyzed mat3-M expression was significantly higher than mat2-P expression. The mutations define three new genes, clr2, clr3 and clr4. In addition we show that the rik1 mutant previously known to allow recombination in the K region also depresses the silent loci.

  2. A New Quaternary Structure Epitope on Dengue Virus Serotype 2 Is the Target of Durable Type-Specific Neutralizing Antibodies

    PubMed Central

    Gallichotte, E. N.; Widman, D. G.; Yount, B. L.; Wahala, W. M.; Durbin, A.; Whitehead, S.; Sariol, C. A.; Crowe, J. E.

    2015-01-01

    ABSTRACT Dengue virus serotype 2 (DENV2) is widespread and responsible for severe epidemics. While primary DENV2 infections stimulate serotype-specific protective responses, a leading vaccine failed to induce a similar protective response. Using human monoclonal antibodies (hMAbs) isolated from dengue cases and structure-guided design of a chimeric DENV, here we describe the major site on the DENV2 envelope (E) protein targeted by neutralizing antibodies. DENV2-specific neutralizing hMAb 2D22 binds to a quaternary structure epitope. We engineered and recovered a recombinant DENV4 that displayed the 2D22 epitope. DENV2 neutralizing antibodies in people exposed to infection or a live vaccine tracked with the 2D22 epitope on the DENV4/2 chimera. The chimera remained sensitive to DENV4 antibodies, indicating that the major neutralizing epitopes on DENV2 and -4 are at different sites. The ability to transplant a complex epitope between DENV serotypes demonstrates a hitherto underappreciated structural flexibility in flaviviruses, which could be harnessed to develop new vaccines and diagnostics. PMID:26463165

  3. The mating type-specific homeodomain genes SXI1 alpha and SXI2a coordinately control uniparental mitochondrial inheritance in Cryptococcus neoformans.

    PubMed

    Yan, Zhun; Hull, Christina M; Sun, Sheng; Heitman, Joseph; Xu, Jianping

    2007-03-01

    In the great majority of sexual eukaryotes, mitochondrial genomes are inherited almost exclusively from a single parent. While many hypotheses have been proposed to explain this phenomenon, very little is known about the genetic elements controlling uniparental mitochondria inheritance. In the bipolar, isogamous basidiomycete yeast Cryptococcus neoformans, progeny from crosses between strains of mating type a (MATa) and mating type alpha (MATalpha) typically inherit mitochondrial DNA (mtDNA) from the MATa parent. We recently demonstrated that a mating type alpha (MATalpha)-specific gene SXI1a, controls mitochondrial inheritance in C. neoformans. Here, we show that another homeodomain gene SXI2a in the alternative mating type MATa is also required for uniparental mtDNA inheritance in this fungus. Disruption of SXI2a resulted in biparental mtDNA inheritance in the zygote population with significant numbers of progeny inheriting mtDNA from the MATa parent, the MATalpha parent, and both the MATa and the MATalpha parents. In addition, progeny from same-sex mating between MATalpha strains showed a biparental mitochondrial inheritance pattern. Our results suggest that SXI1alpha and SXI2a coordinately control uniparental mitochondrial inheritance in C. neoformans.

  4. Neutralization serotypes of human immunodeficiency virus type 1 field isolates are not predicted by genetic subtype. The WHO Network for HIV Isolation and Characterization.

    PubMed Central

    Weber, J; Fenyö, E M; Beddows, S; Kaleebu, P; Björndal, A

    1996-01-01

    Human immunodeficiency virus type 1 (HIV-1) primary isolates from four geographical locations in Thailand, Brazil, Rwanda, and Uganda, representing genetic subtypes A, B, C, D, and E, were examined for autologous and heterologous neutralization by panels of human HIV+ polyclonal plasma. In independent linked experiments in three laboratories using diverse methodologies and common reagents, no defined pattern of genetic subtype-specific neutralization was observed. Most plasma tested were broadly cross-neutralizing across two or more genetic subtypes, although the titer of neutralization varied across a wide range. We conclude that the genetic subtypes of HIV-1 are not classical neutralization serotypes. PMID:8892904

  5. αADα Hybrids of Cryptococcus neoformans: Evidence of Same-Sex Mating in Nature and Hybrid Fitness

    PubMed Central

    Lin, Xiaorong; Litvintseva, Anastasia P; Nielsen, Kirsten; Patel, Sweta; Floyd, Anna; Mitchell, Thomas G; Heitman, Joseph

    2007-01-01

    Cryptococcus neoformans is a ubiquitous human fungal pathogen that causes meningoencephalitis in predominantly immunocompromised hosts. The fungus is typically haploid, and sexual reproduction involves two individuals with opposite mating types/sexes, α and a. However, the overwhelming predominance of mating type (MAT) α over a in C. neoformans populations limits α–a mating in nature. Recently it was discovered that C. neoformans can undergo same-sex mating under laboratory conditions, especially between α isolates. Whether same-sex mating occurs in nature and contributes to the current population structure was unknown. In this study, natural αADα hybrids that arose by fusion between two α cells of different serotypes (A and D) were identified and characterized, providing definitive evidence that same-sex mating occurs naturally. A novel truncated allele of the mating-type-specific cell identity determinant SXI1α was also identified as a genetic factor likely involved in this process. In addition, laboratory-constructed αADα strains exhibited hybrid vigor both in vitro and in vivo, providing a plausible explanation for their relative abundance in nature despite the fact that AD hybrids are inefficient in meiosis/sporulation and are trapped in the diploid state. These findings provide insights on the origins, genetic mechanisms, and fitness impact of unisexual hybridization in the Cryptococcus population. PMID:17953489

  6. Maintenance of Sex-Related Genes and the Co-Occurrence of Both Mating Types in Verticillium dahliae

    PubMed Central

    Hu, Xiaoping; Inderbitzin, Patrik; Subbarao, Krishna V.

    2014-01-01

    Verticillium dahliae is a cosmopolitan, soilborne fungus that causes a significant wilt disease on a wide variety of plant hosts including economically important crops, ornamentals, and timber species. Clonal expansion through asexual reproduction plays a vital role in recurring plant epidemics caused by this pathogen. The recent discovery of recombination between clonal lineages and preliminary investigations of the meiotic gene inventory of V. dahliae suggest that cryptic sex appears to be rare in this species. Here we expanded on previous findings on the sexual nature of V. dahliae. Only 1% of isolates in a global collection of 1120 phytopathogenic V. dahliae isolates contained the MAT1-1 idiomorph, whereas 99% contained MAT1-2. Nine unique multilocus microsatellite types comprised isolates of both mating types, eight of which were collected from the same substrate at the same time. Orthologs of 88 previously characterized sex-related genes from fungal model systems in the Ascoymycota were identified in the genome of V. dahliae, out of 93 genes investigated. Results of RT-PCR experiments using both mating types revealed that 10 arbitrarily chosen sex-related genes, including MAT1-1-1 and MAT1-2-1, were constitutively expressed in V. dahliae cultures grown under laboratory conditions. Ratios of non-synonymous (amino-acid altering) to synonymous (silent) substitutions in V. dahliae MAT1-1-1 and MAT1-2-1 sequences were indistinguishable from the ratios observed in the MAT genes of sexual fungi in the Pezizomycotina. Patterns consistent with strong purifying selection were also observed in 18 other arbitrarily chosen V. dahliae sex-related genes, relative to the patterns in orthologs from fungi with known sexual stages. This study builds upon recent findings from other laboratories and mounts further evidence for an ancestral or cryptic sexual stage in V. dahliae. PMID:25383550

  7. Cloning of mating-type gene MAT1-1 from the caterpillar medicinal mushroom, Cordyceps militaris (Ascomycetes) using TAIL-PCR technology.

    PubMed

    Cong, Wei-Ran; Gong, Zhen-Hua; Shi, Dan-Dan; Guo, Hui; Zhou, Xuanwei

    2014-01-01

    Cordyceps militaris and Ophiocordyceps sinensis (syn. Cordyceps sinensis), 2 well-known traditional Chinese medicines, contain the same bioactive components and share a similar developmental process. In this study, one C. militaris strain preserved in our laboratory was proven to be a MAT1 mating-type strain using a polymerase chain reaction-based mating-type assay. A 5000-bp nucleotide sequence of the mating-type MAT1-1 from C. militaris was amplified by thermal asymmetric interlaced polymerase chain reaction, but genes within the mating-type MAT1-2 remain undetectable. Sequence analysis shows that the mating-type gene MAT1-1 idiomorph contains 2 genes, MAT1-1-1 and MAT1-1-2. The MAT1-1-1 gene consists of 1480-bp nucleotides that encode 456 amino acids and contain the conserved a-box domain interrupted by 2 introns; the MAT1-1-2 gene consists of 1066 nucleotides that encode 377 amino acids interrupted by one intron. The intervening distance between MAT1-1-1 and MAT1-1-2 is 778 bp. The C. militaris MAT1-1 idiomorph organization is the same as that of Cordyceps takaomontana. The MAT1-1 mating-type idiomorph of both Cordyceps species lacks the MAT1-1-3 gene, which is typically present in Pyrenomycetes. These studies provide some insights for further study of the morphological development of C. militaris and will eventually benefit the domestication of O. sinensis.

  8. Analysis of Clostridium botulinum Serotype E Strains by Using Multilocus Sequence Typing, Amplified Fragment Length Polymorphism, Variable-Number Tandem-Repeat Analysis, and Botulinum Neurotoxin Gene Sequencing▿

    PubMed Central

    Macdonald, Thomas E.; Helma, Charles H.; Shou, Yulin; Valdez, Yolanda E.; Ticknor, Lawrence O.; Foley, Brian T.; Davis, Stephen W.; Hannett, George E.; Kelly-Cirino, Cassandra D.; Barash, Jason R.; Arnon, Stephen S.; Lindström, Miia; Korkeala, Hannu; Smith, Leonard A.; Smith, Theresa J.; Hill, Karen K.

    2011-01-01

    A total of 41 Clostridium botulinum serotype E strains from different geographic regions, including Canada, Denmark, Finland, France, Greenland, Japan, and the United States, were compared by multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) analysis, variable-number tandem-repeat (VNTR) analysis, and botulinum neurotoxin (bont) E gene sequencing. The strains, representing environmental, food-borne, and infant botulism samples collected from 1932 to 2007, were analyzed to compare serotype E strains from different geographic regions and types of botulism and to determine whether each of the strains contained the transposon-associated recombinase rarA, involved with bont/E insertion. MLST examination using 15 genes clustered the strains into several clades, with most members within a cluster sharing the same BoNT/E subtype (BoNT/E1, E2, E3, or E6). Sequencing of the bont/E gene identified two new variants (E7, E8) that showed regions of recombination with other E subtypes. The AFLP dendrogram clustered the 41 strains similarly to the MLST dendrogram. Strains that could not be differentiated by AFLP, MLST, or bont gene sequencing were further examined using three VNTR regions. Both intact and split rarA genes were amplified by PCR in each of the strains, and their identities were confirmed in 11 strains by amplicon sequencing. The findings suggest that (i) the C. botulinum serotype E strains result from the targeted insertion of the bont/E gene into genetically conserved bacteria and (ii) recombination events (not random mutations) within bont/E result in toxin variants or subtypes within strains. PMID:22003031

  9. Mating system, feeding type and ex situ conservation effort determine life expectancy in captive ruminants.

    PubMed

    Müller, Dennis W H; Lackey, Laurie Bingaman; Streich, W Jürgen; Fickel, Jörns; Hatt, Jean-Michel; Clauss, Marcus

    2011-07-07

    Zoo animal husbandry aims at constantly improving husbandry, reproductive success and ultimately animal welfare. Nevertheless, analyses to determine factors influencing husbandry of different species are rare. The relative life expectancy (rLE; life expectancy (LE) as proportion of longevity) describes husbandry success of captive populations. Correlating rLE with biological characteristics of different species, reasons for variation in rLE can be detected. We analysed data of 166 901 animals representing 78 ruminant species kept in 850 facilities. The rLE of females correlated with the percentage of grass in a species' natural diet, suggesting that needs of species adapted to grass can be more easily accommodated than the needs of those adapted to browse. Males of monogamous species demonstrate higher rLE than polygamous males, which matches observed differences of sexual bias in LE in free-living populations and thus supports the ecological theory that the mating system influences LE. The third interesting finding was that rLE was higher in species managed by international studbooks when compared with species not managed in this way. Our method facilitates the identification of biological characteristics of species that are relevant for their husbandry success, and they also support ecological theory. Translating these findings into feeding recommendations, our approach can help to improve animal husbandry.

  10. Mating system, feeding type and ex situ conservation effort determine life expectancy in captive ruminants

    PubMed Central

    Müller, Dennis W. H.; Lackey, Laurie Bingaman; Streich, W. Jürgen; Fickel, Jörns; Hatt, Jean-Michel; Clauss, Marcus

    2011-01-01

    Zoo animal husbandry aims at constantly improving husbandry, reproductive success and ultimately animal welfare. Nevertheless, analyses to determine factors influencing husbandry of different species are rare. The relative life expectancy (rLE; life expectancy (LE) as proportion of longevity) describes husbandry success of captive populations. Correlating rLE with biological characteristics of different species, reasons for variation in rLE can be detected. We analysed data of 166 901 animals representing 78 ruminant species kept in 850 facilities. The rLE of females correlated with the percentage of grass in a species' natural diet, suggesting that needs of species adapted to grass can be more easily accommodated than the needs of those adapted to browse. Males of monogamous species demonstrate higher rLE than polygamous males, which matches observed differences of sexual bias in LE in free-living populations and thus supports the ecological theory that the mating system influences LE. The third interesting finding was that rLE was higher in species managed by international studbooks when compared with species not managed in this way. Our method facilitates the identification of biological characteristics of species that are relevant for their husbandry success, and they also support ecological theory. Translating these findings into feeding recommendations, our approach can help to improve animal husbandry. PMID:21147792

  11. Molecular genetic analyses of mating pheromones reveal intervariety mating or hybridization in Cryptococcus neoformans.

    PubMed

    Chaturvedi, Vishnu; Fan, Jinjiang; Stein, Birgit; Behr, Melissa J; Samsonoff, William A; Wickes, Brian L; Chaturvedi, Sudha

    2002-09-01

    The sexual mating of the pathogenic yeast Cryptococcus neoformans is important for pathogenesis studies because the fungal virulence is linked to the alpha mating type (MAT(alpha)). We characterized C. neoformans mating pheromones (MF(alpha) 1 and MFa1) from 122 strains to understand intervariety hybridization or mating and intervariety virulence. MF(alpha) 1 in three C. neoformans varieties showed (a) specific nucleotide polymorphisms, (b) different copy numbers and chromosomal localizations, and (c) unique deduced amino acids in two geographic populations of C. neoformans var. gattii. MF(alpha) 1 of different varieties cross-hybridized in Southern hybridizations. Their phylogenetic analyses showed purifying selection (neutral evolution). These observations suggested that MAT(alpha) strains from any of the three C. neoformans varieties could mate or hybridize in nature with MATa strains of C. neoformans var. neoformans. A few serotype A/D diploid strains provided evidence for mating or hybridization, while a majority of A/D strains tested positive for haploid MF(alpha) 1 identical to that of C. neoformans var. grubii. MF(alpha) 1 sequence and copy numbers in diploids were identical to those of C. neoformans var. grubii, while their MFa1 sequences were identical to those of C. neoformans var. neoformans; thus, these strains were hybrids. The mice survival curves and histological lesions revealed A/D diploids to be highly pathogenic, with pathogenicity levels similar to that of the C. neoformans var. grubii type strain and unlike the low pathogenicity levels of C. neoformans var. neoformans strains. In contrast to MF(alpha) 1 in three varieties, MFa1 amplicons and hybridization signals could be obtained only from two C. neoformans var. neoformans reference strains and eight A/D diploids. This suggested that a yet undiscovered MFa pheromone(s) in C. neoformans var. gattii and C. neoformans var. grubii is unrelated to, highly divergent from, or rarer than that in C

  12. Unequal Recombination and Evolution of the Mating-Type (MAT) Loci in the Pathogenic Fungus Grosmannia clavigera and Relatives

    PubMed Central

    Tsui, Clement K.-M.; DiGuistini, Scott; Wang, Ye; Feau, Nicolas; Dhillon, Braham; Bohlmann, Jörg; Hamelin, Richard C.

    2013-01-01

    Sexual reproduction in fungi is regulated by the mating-type (MAT) locus where recombination is suppressed. We investigated the evolution of MAT loci in eight fungal species belonging to Grosmannia and Ophiostoma (Sordariomycetes, Ascomycota) that include conifer pathogens and beetle symbionts. The MAT1-2 idiomorph/allele was identified from the assembled and annotated Grosmannia clavigera genome, and the MAT locus is flanked by genes coding for cytoskeleton protein (SLA) and DNA lyase. The synteny of these genes is conserved and consistent with other members in Ascomycota. Using sequences from SLA and flanking regions, we characterized the MAT1-1 idiomorph from other isolates of G. clavigera and performed dotplot analysis between the two idiomorphs. Unexpectedly, the MAT1-2 idiomorph contains a truncated MAT1-1-1 gene upstream of the MAT1-2-1 gene that bears the high-mobility-group domain. The nucleotide and amino acid sequence of the truncated MAT1-1-1 gene is similar to its homologous copy in the MAT1-1 idiomorph in the opposite mating-type isolate, except that positive selection is acting on the truncated gene and the alpha(α)-box that encodes the transcription factor has been deleted. The MAT idiomorphs sharing identical gene organization were present in seven additional species in the Ophiostomatales, suggesting that the presence of truncated MAT1-1-1 gene is a general pattern in this order. We propose that an ancient unequal recombination event resulted in the ancestral MAT1-1-1 gene integrated into the MAT1-2 idiomorph and surviving as the truncated MAT1-1-1 genes. The α-box domain of MAT1-1-1 gene, located at the same MAT locus adjacent to the MAT1-2-1 gene, could have been removed by deletion after recombination due to mating signal interference. Our data confirmed a 1:1 MAT/sex ratio in two pathogen populations, and showed that all members of the Ophiostomatales studied here including those that were previously deemed asexual have the potential to

  13. Mating in parents of type 1 diabetes families as a function of the HLA DR-DQ haplotype

    PubMed Central

    Kahles, H.; Kordonouri, O.; Ramos Lopez, E.; Walter, M.; Rosinger, S.; Boehm, B. O.; Badenhoop, K.; Seidl, C.; Ziegler, A.

    2009-01-01

    Aim The Major Histocompatibility Complex (MHC) region on chromosome 6p21 (IDDM1) contributes about half of the familial clustering of type 1 diabetes (T1D). Several studies have revealed that highly polymorphic genes within the MHC may associate with the mating choice. Our study should determine whether a specific mating effect is detectable in T1D families as a function of human leucocyte antigen (HLA) DR-DQ, which could contribute to disease susceptibility. Methods We analysed the parental HLA-DR genotypes in 829 diabetic families. The families derive from the Type 1 Diabetes Genetics Consortium (T1DGC) in addition to those of our own centre and the original UK, US and SCAND diabetic families. Results A total of 307 of 829 parental couples (37.0%) were matched for at least one known T1D risk haplotype (DR3 or DR4), which is significantly less than the expected 374.9 (45.2%), derived from population genotype frequencies (p < 0.0009). Parents share less susceptibility haplotypes and rather complement each other as both carry one different risk haplotype (DR3 or DR4). The number of such parental couples was significantly higher than expected (293 vs. 223.4; p < 0.0003). All non-transmitted DR haplotype pairs were also analysed. More often than expected, both parents did not transmit DR1 (94 vs. 59.1; p < 0.003) and DRy (y: not DR1, not DR3, not DR4; 63 vs. 30.3; p < 0.0005). In contrast, the parental non-transmitted pair of haplotypes DR1-DRy was observed to a far lesser extent than expected (26 vs. 84.7; p < 10−8). These observations were only made in multiplex families, whereas in simplex families, no deviation from the expected frequencies was observed. Conclusions Our data are consistent with the conclusion that genes in the HLA region may influence the mating choice in parents of T1D patients, thus contributing to familial clustering of T1D in multiplex families. This may indicate a different parental background of multiplex compared with simplex T1D families

  14. Haemophilus influenzae serotype b and a capsule-deficient type mutant (b-) invasive disease in a partially vaccinated child in Brazil.

    PubMed

    Caldeira, Nathalia G S; de Filippis, Ivano; Arruda, Tânia Catão; Real, Maria Eulália Côrte; de Jesus, Alice Batalha; de Almeida, Antonio Eugenio C C

    2013-04-01

    We report a rare case of infection by two different types of Haemophilus influenzae strains in a child who received only one dose of the H. influenzae serotype b (Hib) conjugate vaccine (DTwP+Hib). The strains were recovered from blood and cerebrospinal fluid (CSF) and were phenotypically identified as Hib and non-typable H. influenzae, respectively, after serological tests. The two strains were characterized by PCR capsular typing, multilocus sequence typing and PFGE. Our results suggest that the infection was caused by the bloodstream invasion by a single Hib strain, followed by the diffusion of the bacteria across the blood-brain barrier and into the CSF. The strain recovered from the CSF, however, was identified as a capsule-deficient type mutant (b(-)) strain. Despite the high efficacy of the Hib conjugate vaccine, the increase in the numbers of strains able to escape the immune system of the vaccinated population advocates continued surveillance.

  15. The Transcription Factor Rbf1 Is the Master Regulator for b-Mating Type Controlled Pathogenic Development in Ustilago maydis

    PubMed Central

    Vranes, Miroslav; Wahl, Ramon; Pothiratana, Chetsada; Schuler, David; Vincon, Volker; Finkernagel, Florian; Flor-Parra, Ignacio; Kämper, Jörg

    2010-01-01

    In the phytopathogenic basidiomycete Ustilago maydis, sexual and pathogenic development are tightly connected and controlled by the heterodimeric bE/bW transcription factor complex encoded by the b-mating type locus. The formation of the active bE/bW heterodimer leads to the formation of filaments, induces a G2 cell cycle arrest, and triggers pathogenicity. Here, we identify a set of 345 bE/bW responsive genes which show altered expression during these developmental changes; several of these genes are associated with cell cycle coordination, morphogenesis and pathogenicity. 90% of the genes that show altered expression upon bE/bW-activation require the zinc finger transcription factor Rbf1, one of the few factors directly regulated by the bE/bW heterodimer. Rbf1 is a novel master regulator in a multilayered network of transcription factors that facilitates the complex regulatory traits of sexual and pathogenic development. PMID:20700446

  16. The transcription factor Rbf1 is the master regulator for b-mating type controlled pathogenic development in Ustilago maydis.

    PubMed

    Heimel, Kai; Scherer, Mario; Vranes, Miroslav; Wahl, Ramon; Pothiratana, Chetsada; Schuler, David; Vincon, Volker; Finkernagel, Florian; Flor-Parra, Ignacio; Kämper, Jörg

    2010-08-05

    In the phytopathogenic basidiomycete Ustilago maydis, sexual and pathogenic development are tightly connected and controlled by the heterodimeric bE/bW transcription factor complex encoded by the b-mating type locus. The formation of the active bE/bW heterodimer leads to the formation of filaments, induces a G2 cell cycle arrest, and triggers pathogenicity. Here, we identify a set of 345 bE/bW responsive genes which show altered expression during these developmental changes; several of these genes are associated with cell cycle coordination, morphogenesis and pathogenicity. 90% of the genes that show altered expression upon bE/bW-activation require the zinc finger transcription factor Rbf1, one of the few factors directly regulated by the bE/bW heterodimer. Rbf1 is a novel master regulator in a multilayered network of transcription factors that facilitates the complex regulatory traits of sexual and pathogenic development.

  17. Transcription of novel genes, including a gene linked to the mating-type locus, induced by Chlamydomonas fertilization.

    PubMed Central

    Ferris, P J; Goodenough, U W

    1987-01-01

    Six cDNA clones have been identified that are complementary to transcripts present in young zygotes of Chlamydomonas reinhardtii but absent from vegetative and gametic cells. Five early transcripts are synthesized within 5 to 10 min of fertilization; the sixth, late, transcript is not synthesized until 90 min following fertilization. Synthesis of both classes requires cell fusion between gametes. Cycloheximide fails to inhibit early mRNA synthesis, indicating that transcription factors must preexist in the gametes and be activated by cytoplasmic confluence. By contrast, cycloheximide blocks synthesis of the late transcript, suggesting that an early protein product(s) is required for expression of the late gene. Restriction fragment length polymorphism analysis of inter- and intraspecific genetic crosses demonstrates that one of the early genes is very tightly linked to the mating-type locus. Images PMID:3614194

  18. Improved detection of nasopharyngeal cocolonization by multiple pneumococcal serotypes by use of latex agglutination or molecular serotyping by microarray.

    PubMed

    Turner, Paul; Hinds, Jason; Turner, Claudia; Jankhot, Auscharee; Gould, Katherine; Bentley, Stephen D; Nosten, François; Goldblatt, David

    2011-05-01

    Identification of Streptococcus pneumoniae in the nasopharynx is critical for an understanding of transmission, estimates of vaccine efficacy, and possible replacement disease. Conventional nasopharyngeal swab (NPS) culture and serotyping (the WHO protocol) is likely to underestimate multiple-serotype carriage. We compared the WHO protocol with methods aimed at improving cocolonization detection. One hundred twenty-five NPSs from an infant pneumococcal-carriage study, containing ≥ 1 serotype by WHO culture, were recultured in duplicate. A sweep of colonies from one plate culture was serotyped by latex agglutination. DNA extracted from the second plate was analyzed by S. pneumoniae molecular-serotyping microarray. Multiple serotypes were detected in 11.2% of the swabs by WHO culture, 43.2% by sweep serotyping, and 48.8% by microarray. Sweep and microarray were more likely to detect multiple serotypes than WHO culture (P < 0.0001). Cocolonization detection rates were similar between microarray and sweep, but the microarray identified the greatest number of serotypes. A common serogroup type was identified in 95.2% of swabs by all methods. WHO methodology significantly underestimates multiple-serotype carriage compared to these alternate methods. Sweep serotyping is cost-effective and field deployable but may fail to detect serotypes at low abundance, whereas microarray serotyping is more costly and technology dependent but may detect these additional minor carried serotypes.

  19. MLST and Whole-Genome-Based Population Analysis of Cryptococcus gattii VGIII Links Clinical, Veterinary and Environmental Strains, and Reveals Divergent Serotype Specific Sub-populations and Distant Ancestors

    PubMed Central

    Firacative, Carolina; Roe, Chandler C.; Malik, Richard; Ferreira-Paim, Kennio; Escandón, Patricia; Sykes, Jane E.; Castañón-Olivares, Laura Rocío; Contreras-Peres, Cudberto; Samayoa, Blanca; Sorrell, Tania C.; Castañeda, Elizabeth; Lockhart, Shawn R.; Engelthaler, David M.; Meyer, Wieland

    2016-01-01

    The emerging pathogen Cryptococcus gattii causes life-threatening disease in immunocompetent and immunocompromised hosts. Of the four major molecular types (VGI-VGIV), the molecular type VGIII has recently emerged as cause of disease in otherwise healthy individuals, prompting a need to investigate its population genetic structure to understand if there are potential genotype-dependent characteristics in its epidemiology, environmental niche(s), host range and clinical features of disease. Multilocus sequence typing (MLST) of 122 clinical, environmental and veterinary C. gattii VGIII isolates from Australia, Colombia, Guatemala, Mexico, New Zealand, Paraguay, USA and Venezuela, and whole genome sequencing (WGS) of 60 isolates representing all established MLST types identified four divergent sub-populations. The majority of the isolates belong to two main clades, corresponding either to serotype B or C, indicating an ongoing species evolution. Both major clades included clinical, environmental and veterinary isolates. The C. gattii VGIII population was genetically highly diverse, with minor differences between countries, isolation source, serotype and mating type. Little to no recombination was found between the two major groups, serotype B and C, at the whole and mitochondrial genome level. C. gattii VGIII is widespread in the Americas, with sporadic cases occurring elsewhere, WGS revealed Mexico and USA as a likely origin of the serotype B VGIII population and Colombia as a possible origin of the serotype C VGIII population. Serotype B isolates are more virulent than serotype C isolates in a murine model of infection, causing predominantly pulmonary cryptococcosis. No specific link between genotype and virulence was observed. Antifungal susceptibility testing against six antifungal drugs revealed that serotype B isolates are more susceptible to azoles than serotype C isolates, highlighting the importance of strain typing to guide effective treatment to improve the

  20. A serotype-specific polymerase chain reaction for identification of Pasteurella multocida serotype 1

    USGS Publications Warehouse

    Rocke, T.E.; Smith, S.R.; Miyamoto, A.; Shadduck, D.J.

    2002-01-01

    A serotype-specific polymerase chain reaction (PCR) assay was developed for detection and identification of Pasteurella multocida serotype 1, the causative agent of avian cholera in wild waterfowl. Arbitrarily primed PCR was used to detect DNA fragments that distinguish serotype 1 from the other 15 serotypes of P. multocida (with the exception of serotype 14). Oligonucleotide primers were constructed from these sequences, and a PCR assay was optimized and evaluated. PCR reactions consistently resulted in amplification products with reference strains 1 and 14 and all other serotype 1 strains tested, with cell numbers as low as 2.3 cells/ml. No amplification products were produced with other P. multocida serotypes or any other bacterial species tested. To compare the sensitivity and further test the specificity of this PCR assay with traditional culturing and serotyping techniques, tissue samples from 84 Pekin ducks inoculated with field strains of P. multocida and 54 wild lesser snow geese collected during an avian cholera outbreak were provided by other investigators working on avian cholera. PCR was as sensitive (58/64) as routine isolation (52/64) in detecting and identifying P. multocida serotype 1 from the livers of inoculated Pekins that became sick or died from avian cholera. No product was amplified from tissues of 20 other Pekin ducks that received serotypes other than type 1 (serotype 3, 12 × 3, or 10) or 12 control birds. Of the 54 snow geese necropsied and tested for P. multocida, our PCR detected and identified the bacteria from 44 compared with 45 by direct isolation. The serotype-specific PCR we developed was much faster and less labor intensive than traditional culturing and serotyping procedures and could result in diagnosis of serotype 1 pasteurellosis within 24 hr of specimen submission.

  1. A serotype-specific polymerase chain reaction for identification of Pasteurella multocida serotype 1

    USGS Publications Warehouse

    Rocke, Tonie E.; Smith, Susan R.; Miyamoto, Amy; Shadduck, Daniel J.

    2002-01-01

    A serotype-specific polymerase chain reaction (PCR) assay was developed for detection and identification of Pasteurella multocida serotype 1, the causative agent of avian cholera in wild waterfowl. Arbitrarily primed PCR was used to detect DNA fragments that distinguish serotype 1 from the other 15 serotypes of P. multocida (with the exception of serotype 14). Oligonucleotide primers were constructed from these sequences, and a PCR assay was optimized and evaluated. PCR reactions consistently resulted in amplification products with reference strains 1 and 14 and all other serotype 1 strains tested, with cell numbers as low as 2.3 cells/ml. No amplification products were produced with other P. multocida serotypes or any other bacterial species tested. To compare the sensitivity and further test the specificity of this PCR assay with traditional culturing and serotyping techniques, tissue samples from 84 Pekin ducks inoculated with field strains of P. multocida and 54 wild lesser snow geese collected during an avian cholera outbreak were provided by other investigators working on avian cholera. PCR was as sensitive (58/64) as routine isolation (52/64) in detecting and identifying P. multocida serotype 1 from the livers of inoculated Pekins that became sick or died from avian cholera. No product was amplified from tissues of 20 other Pekin ducks that received serotypes other than type 1 (serotype 3, 12 × 3, or 10) or 12 control birds. Of the 54 snow geese necropsied and tested for P. multocida, our PCR detected and identified the bacteria from 44 compared with 45 by direct isolation. The serotype-specific PCR we developed was much faster and less labor intensive than traditional culturing and serotyping procedures and could result in diagnosis of serotype 1 pasteurellosis within 24 hr of specimen submission.

  2. A serotype-specific polymerase chain reaction for identification of Pasteurella multocida serotype 1.

    PubMed

    Rocke, Tonie E; Smith, Susan R; Miyamoto, Amy; Shadduck, Daniel J

    2002-01-01

    A serotype-specific polymerase chain reaction (PCR) assay was developed for detection and identification of Pasteurella multocida serotype 1, the causative agent of avian cholera in wild waterfowl. Arbitrarily primed PCR was used to detect DNA fragments that distinguish serotype 1 from the other 15 serotypes of P. multocida (with the exception of serotype 14). Oligonucleotide primers were constructed from these sequences, and a PCR assay was optimized and evaluated. PCR reactions consistently resulted in amplification products with reference strains 1 and 14 and all other serotype 1 strains tested, with cell numbers as low as 2.3 cells/ml. No amplification products were produced with other P. multocida serotypes or any other bacterial species tested. To compare the sensitivity and further test the specificity of this PCR assay with traditional culturing and serotyping techniques, tissue samples from 84 Pekin ducks inoculated with field strains of P. multocida and 54 wild lesser snow geese collected during an avian cholera outbreak were provided by other investigators working on avian cholera. PCR was as sensitive (58/64) as routine isolation (52/64) in detecting and identifying P. multocida serotype 1 from the livers of inoculated Pekins that became sick or died from avian cholera. No product was amplified from tissues of 20 other Pekin ducks that received serotypes other than type 1 (serotype 3, 12 x 3, or 10) or 12 control birds. Of the 54 snow geese necropsied and tested for P. multocida, our PCR detected and identified the bacteria from 44 compared with 45 by direct isolation. The serotype-specific PCR we developed was much faster and less labor intensive than traditional culturing and serotyping procedures and could result in diagnosis of serotype 1 pasteurellosis within 24 hr of specimen submission.

  3. A phase I trial of adeno-associated virus serotype 1-γ-sarcoglycan gene therapy for limb girdle muscular dystrophy type 2C.

    PubMed

    Herson, Serge; Hentati, Faycal; Rigolet, Aude; Behin, Anthony; Romero, Norma B; Leturcq, France; Laforêt, Pascal; Maisonobe, Thierry; Amouri, Rim; Haddad, Hafedh; Audit, Muriel; Montus, Marie; Masurier, Carole; Gjata, Bernard; Georger, Christophe; Cheraï, Mustapha; Carlier, Pierre; Hogrel, Jean-Yves; Herson, Ariane; Allenbach, Yves; Lemoine, François M; Klatzmann, David; Sweeney, H Lee; Mulligan, Richard C; Eymard, Bruno; Caizergues, Didier; Voït, Thomas; Benveniste, Olivier

    2012-02-01

    γ-Sarcoglycanopathy or limb girdle muscular dystrophy type 2C is an untreatable disease caused by autosomal recessively inherited mutations of the γ-sarcoglycan gene. Nine non-ambulatory patients (two males, seven females, mean age 27 years; range 16-38 years) with del525T homozygous mutation of the γ-sarcoglycan gene and no γ-sarcoglycan immunostaining on muscle biopsy were divided into three equal groups to receive three escalating doses of an adeno-associated virus serotype 1 vector expressing the human γ-sarcoglycan gene under the control of the desmin promoter, by local injection into the extensor carpi radialis muscle. The first group received a single injection of 3 × 10(9) viral genomes in 100 µl, the second group received a single injection of 1.5 × 10(10) viral genomes in 100 µl, and the third group received three simultaneous 100-µl injections at the same site, delivering a total dose of 4.5 × 10(10) viral genomes. No serious adverse effects occurred during 6 months of follow-up. All nine patients became adeno-associated virus serotype 1 seropositive and one developed a cytotoxic response to the adeno-associated virus serotype 1 capsid. Thirty days later, immunohistochemical analysis of injected-muscle biopsy specimens showed γ-sarcoglycan expression in all three patients who received the highest dose (4.7-10.5% positively stained fibres), while real-time polymerase chain reaction detected γ-sarcoglycan messenger RNA. In one patient, γ-sarcoglycan protein was detected by western blot. For two other patients who received the low and intermediate doses, discrete levels of γ-sarcoglycan expression (<1% positively stained fibres) were also detectable. Expression of γ-sarcoglycan protein can be induced in patients with limb girdle muscular dystrophy type 2C by adeno-associated virus serotype 1 gene transfer, with no serious adverse effects.

  4. Novel Rotavirus VP7 Typing Assay Using a One-Step Reverse Transcriptase PCR Protocol and Product Sequencing and Utility of the Assay for Epidemiological Studies and Strain Characterization, Including Serotype Subgroup Analysis

    PubMed Central

    DiStefano, Daniel J.; Kraiouchkine, Nikolai; Mallette, Laura; Maliga, Marianne; Kulnis, Gregory; Keller, Paul M.; Clark, H. Fred; Shaw, Alan R.

    2005-01-01

    Rotavirus is the most common cause of severe dehydrating gastroenteritis in infants. To date, 10 different serotypes of rotavirus have been identified in human stools. While four or five serotypes dominate, serotype circulation varies with season and geography. Since our laboratory has been involved in the development of a multivalent rotavirus vaccine, it is important to identify the serotypes of rotavirus encountered during our clinical trials. We have developed methodologies for the molecular identification of rotavirus strains based on VP7 gene segment sequence. A 365-bp reverse transcriptase PCR product was generated from the VP7 gene segment using a pair of novel degenerate primers. All serotypes tested (both animal and human) yielded an identically sized product after amplification. Sequencing of these products is performed using truncated versions of the original primers. The sequence generated is compared against a database of rotavirus VP7 sequences, with the G type determined, based on the sequence homology. Using this assay, we have correctly identified human VP7 strains from a panel of available serotypes, as well as numerous animal strains. The assay was qualified using rotavirus positive stool samples, negative stool samples, and rotavirus-spiked stool samples. In addition, samples from cases of acute gastroenteritis collected at Children's Hospital of Philadelphia have been evaluated and indicate that the assay is able to discriminate subtle differences within serotypes. The assay has been utilized in the testing of >3,000 antigen-positive (enzyme immunoassay) samples collected during clinical trials of a rotavirus vaccine (RotaTeq) and identified a serotype in ∼92% of samples (3, 17, 19). PMID:16333070

  5. Species D Human Adenovirus Type 9 Exhibits Better Virus-Spread Ability for Antitumor Efficacy among Alternative Serotypes

    PubMed Central

    Uchino, Junji; Curiel, David T.; Ugai, Hideyo

    2014-01-01

    Species C human adenovirus serotype 5 (HAdV-C5) is widely used as a vector for cancer gene therapy, because it efficiently transduces target cells. A variety of HAdV-C5 vectors have been developed and tested in vitro and in vivo for cancer gene therapy. While clinical trials with HAdV-C5 vectors resulted in effective responses in many cancer patients, administration of HAdV-C5 vectors to solid tumors showed responses in a limited area. A biological barrier in tumor mass is considered to hinder viral spread of HAdV-C5 vectors from infected cells. Therefore, efficient virus-spread from an infected tumor cell to surrounding tumor cells is required for successful cancer gene therapy. In this study, we compared HAdV-C5 to sixteen other HAdV serotypes selected from species A to G for virus-spread ability in vitro. HAdV-D9 showed better virus-spread ability than other serotypes, and its viral progeny were efficiently released from infected cells during viral replication. Although the HAdV-D9 fiber protein contains a binding site for coxsackie B virus and adenovirus receptor (CAR), HAdV-D9 showed expanded tropism for infection due to human CAR (hCAR)-independent attachment to target cells. HAdV-D9 infection effectively killed hCAR-negative cancer cells as well as hCAR-positive cancer cells. These results suggest that HADV-D9, with its better virus-spread ability, could have improved therapeutic efficacy in solid tumors compared to HAdV-C5. PMID:24503714

  6. Adenovirus serotype 35 vector-induced innate immune responses in dendritic cells derived from wild-type and human CD46-transgenic mice: Comparison with a fiber-substituted Ad vector containing fiber proteins of Ad serotype 35.

    PubMed

    Sakurai, Fuminori; Nakashima, Kazuko; Yamaguchi, Tomoko; Ichinose, Takako; Kawabata, Kenji; Hayakawa, Takao; Mizuguchi, Hiroyuki

    2010-12-01

    Recently, much attention has focused on replication-incompetent adenovirus (Ad) vectors containing fiber proteins derived from species B Ad serotype 35 (Ad35) (Ad5F35) and Ad vectors fully constructed from Ad35 as vaccine vectors expressing antigens. However, differences in the transduction properties, including the induction of innate immunity, of Ad5F35 and Ad35 vectors have not been properly and fully examined, partly because the transduction properties of these Ad vectors should be evaluated using nonhuman primates or human CD46-transgenic (CD46TG) mice, which ubiquitously express the primary receptor of Ad35, human CD46, in a pattern similar to that of humans. In the present study, we evaluated innate immune responses of mouse dendritic cells (mDCs) derived from bone marrow cells of wild-type (WT) and CD46TG mice following transduction with Ad serotype 5 (Ad5), fiber-substituted Ad5F35, or Ad35 vectors. Ad5F35 and Ad35 vectors mediated more efficient transduction in mDCs derived from CD46TG mice (CD46TG-mDCs) than did Ad5 vectors. Upregulation of costimulatory molecules and inflammatory cytokine induction by Ad5F35 and Ad35 vectors were significantly higher than those by Ad5 vectors in CD46TG-mDCs. However, the induction properties of the innate immune responses were different between Ad5F35 and Ad35 vectors. Ad35 vectors induced higher levels of costimulatory molecule expression and inflammatory cytokine production than did Ad5F35 vectors in CD46TG-mDCs. Furthermore, intravenous administration of Ad35 vectors in WT and CD46TG mice resulted in higher levels of serum interleukin (IL)-6 and IL-12 compared with administration of Ad5F35 vectors, which exhibited almost mock-transduced levels of these inflammatory cytokines. This study indicates that innate immune responses by Ad35 and Ad5F35 vectors are distinct even although both Ad vectors recognize human CD46 as a receptor.

  7. Genomewide analysis of MATE-type gene family in maize reveals microsynteny and their expression patterns under aluminum treatment.

    PubMed

    Zhu, Huasheng; Wu, Jiandong; Jiang, Yingli; Jin, Jing; Zhou, Wei; Wang, Yu; Han, Guomin; Zhao, Yang; Cheng, Beijiu

    2016-09-01

    Multidrug and toxic compound extrusion (MATE) proteins are a group of secondary active transporters, which widely exist in all living organisms and play important role in the detoxication of endogenous secondary metabolites and exogenous agents. However, to date, no systematic and comprehensive study of this family is reported in maize. Here, a total of 49 MATE genes (ZmMATE) were identified and divided into seven groups by phylogenetic analysis. Conserved intro-exon structures and motif compositions were investigated in these genes. Results by gene locations indicated that these genes were unevenly distributed among all 10 chromosomes. Tandem and segmental duplications appeared to contribute to the expansion and evolution of this gene family. The Ka/Ks ratios suggested that the ZmMATE has undergone large-scale purifying selection on the maize genome. Interspecies microsynteny analysis revealed that there were independent gene duplication events of 10 ZmMATE. In addition, most maize MATE genes exhibited different expression profiles in diverse tissues and developmental stages. Sixteen MATE genes were chosen for further quantitative real-time polymerase chain reaction analysis showed differential expression patterns in response to aluminum treatment. These results provide a useful clue for future studies on the identification of MATE genes and functional analysis of MATE proteins in maize.

  8. ATP Binding to Hemoglobin Response Gene 1 Protein Is Necessary for Regulation of the Mating Type Locus in Candida albicans*

    PubMed Central

    Peterson, Alexander W.; Pendrak, Michael L.; Roberts, David D.

    2011-01-01

    HBR1 (hemoglobin response gene 1) is an essential gene in Candida albicans that positively regulates mating type locus MTLα gene expression and thereby regulates cell type-specific developmental genes. Hbr1p contains a phosphate-binding loop (P-loop), a highly conserved motif characteristic of ATP- and GTP-binding proteins. Recombinant Hbr1p was isolated in an oligomeric state that specifically bound ATP with Kd ∼2 μm. ATP but not ADP, AMP, GTP, or dATP specifically protected Hbr1p from proteolysis by trypsin. Site-directed mutagenesis of the highly conserved P-loop lysine (K22Q) and the less conserved glycine (G19S) decreased the binding affinity for soluble ATP and ATP immobilized through its γ-phosphate. ATP bound somewhat more avidly than ATPγS to wild type and mutant Hbr1p. Although Hbr1p exhibits sequence motifs characteristic of adenylate kinases, and adenylate kinase and ATPase activities have been reported for the apparent human ortholog of Hbr1p, assays for adenylate kinase activity, autophosphorylation, and ATPase activity proved negative. Overexpression of wild type but not the mutant forms of Hbr1p restored MTlα2 expression in an HBR1/hbr1 mutant, indicating that ATP binding to the P-loop is necessary for this function of Hbr1p. PMID:21372131

  9. Only one of the two type VI secretion systems encoded in the Salmonella enterica serotype Dublin genome is involved in colonization of the avian and murine hosts.

    PubMed

    Pezoa, David; Blondel, Carlos J; Silva, Cecilia A; Yang, Hee-Jeong; Andrews-Polymenis, Helene; Santiviago, Carlos A; Contreras, Inés

    2014-01-09

    The type VI secretion system (T6SS) is a virulence factor for many Gram-negative bacteria. Salmonella genus harbors five phylogenetically distinct T6SS loci encoded in Salmonella Pathogenicity Islands (SPIs) SPI-6, SPI-19, SPI-20, SPI-21 and SPI-22, which are differentially distributed among serotypes. The T6SSs encoded in SPI-6 and SPI-19 contribute to pathogenesis of serotypes Typhimurium and Gallinarum in mice and chickens, respectively. Salmonella Dublin is a pathogen restricted to cattle where it causes a systemic disease. Also, it can colonize other hosts such as chickens and mice, which can act as reservoirs of this serotype. Salmonella Dublin harbors the genes for both T6SS(SPI-6) and T6SS(SPI-19). This study has determined the contribution of T6SS(SPI-6) and T6SS(SPI-19) to host-colonization by Salmonella Dublin using avian and murine models of infection. Competitive index experiments showed that, a mutant strain lacking both T6SSs (∆T6SS(SPI-6)/∆T6SS(SPI-19)) presents a strong colonization defect in cecum of chickens, similar to the defect observed for the ∆T6SS(SPI-6) mutant, suggesting that this serotype requires a functional T6SS(SPI-6) for efficient colonization of the avian gastrointestinal tract. Colonization of mice was also defective, although to a lesser extent than in chickens. In contrast, the T6SS(SPI-19) was not necessary for colonization of either chickens or mice. Transfer of T6SS(SPI-6), but not T6SS(SPI-19), restored the ability of the double mutant to colonize both animal hosts. Our data indicate that Salmonella Dublin requires only the T6SS(SPI-6) for efficient colonization of mice and chickens, and that the T6SS(SPI-6) and T6SS(SPI-19) are not functionally redundant.

  10. Peptidal Sex Hormones Inducing Conjugation Tube Formation in Compatible Mating-Type Cells of Tremella mesenterica.

    PubMed

    Sakagami, Y; Yoshida, M; Isogai, A; Suzuki, A

    1981-06-26

    The pair of peptidal sex hormones (tremerogen A-10 and tremerogen a-13) that induce conjugation tube formation in compatible type cells (A and a types) of Tremella mesenterica were isolated. Tremerogen A-10 is a dodecapeptide and tremerogen a-13, a tridecapeptide. In both peptides, the sulfiydryl group of the cysteines at the carboxyl terminus was blocked by farnesyl moieties.

  11. Cryptococcus neoformans STE12α Regulates Virulence but Is Not Essential for Mating

    PubMed Central

    Chang, Y.C.; Wickes, B.L.; Miller, G.F.; Penoyer, L.A.; Kwon-Chung, K.J.

    2000-01-01

    The Cryptococcus neoformans STE12α gene, a homologue of Saccharomyces cerevisiae STE12, exists only in mating type (MAT)α cells. In S. cerevisiae, STE12 was required for mating and filament formation. In C. neoformans, haploid fruiting on filament agar required STE12α. The ability to form hyphae, however, was not affected by deletion of STE12α when convergently growing MATa strains were present. Furthermore, ste12α disruptants were fertile when mated with MATa strains, albeit with reduced mating frequency. Most importantly, the virulence of a ste12α disruptant of serotype D strain was significantly reduced in a mouse model. When the ste12α locus was reconstituted with the wild-type allele by cotransformation, virulence was restored. Histopathological analysis demonstrated a reduction in capsular size of yeast cells, less severe cystic lesions, and stronger immune responses in meninges of mice infected with ste12α cells than those of mice infected with STE12α cells. Using reporter gene constructs, we found that STE12α controls the expression of several phenotypes known to be involved in virulence, such as capsule and melanin production. These results demonstrate a clear molecular link between mating type and virulence in C. neoformans. PMID:10704467

  12. Molecular Typing and Virulence Analysis of Serotype K1 Klebsiella pneumoniae Strains Isolated from Liver Abscess Patients and Stool Samples from Noninfectious Subjects in Hong Kong, Singapore, and Taiwan ▿

    PubMed Central

    Siu, L. Kristopher; Fung, Chang-Phone; Chang, Feng-Yee; Lee, Nelson; Yeh, Kuo-Ming; Koh, Tse Hsien; Ip, Margaret

    2011-01-01

    Serotype K1 Klebsiella pneumoniae with multilocus sequence type 23 (ST23) has been strongly associated with liver abscess in Taiwan. Few data regarding the strain types and virulence of this serotype from other Asian countries are available. Serotype K1 K. pneumoniae strains isolated from liver abscess and stool samples from subjects hospitalized in Hong Kong, Singapore, and Taiwan hospitals were examined. Forty-seven serotype K1 isolates were identified: 26 from liver abscess samples and 21 from stool samples. MLST revealed 7 sequence types: 85.1% (40 of 47 isolates) belonged to ST23, 1 isolate belonged to ST163 (a single-locus variant of ST23), and 2 isolates were ST249 (a 3-locus variant of ST23). New STs, namely, ST367, ST425, and ST426, were allocated to 3 of 4 isolates from stool samples. The virulence of these strains was determined by neutrophil phagocytosis and mouse infection models. Except for two ST23 isolates, all Klebsiella pneumoniae isolates were resistant to phagocytosis. Resistance to serum killing varied in isolates of ST23, while all non-ST23 strains were susceptible to serum killing except one with ST249 from a liver abscess. All hypervirulent isolates with a 50% lethal dose of <102 CFU were from ST23, were resistant to phagocytosis and serum killing, and also carried both virulence-associated genes, rmpA and aerobactin. Multilocus sequence typing genotype 23 was the most prevalent sequence type among serotype K1 K. pneumoniae isolates from both liver abscess and stool samples in the Asia Pacific region. Serotype K1 K. pneumoniae isolates with capsule expression leading to phagocytic resistance and with the aerobactin gene were associated with hypervirulence. PMID:21900521

  13. Antifungal susceptibility, serotyping, and genotyping of clinical Cryptococcus neoformans isolates collected during 18 years in a single institution in Madrid, Spain.

    PubMed

    Guinea, Jesús; Hagen, Ferry; Peláez, Teresa; Boekhout, Teun; Tahoune, Hicham; Torres-Narbona, Marta; Bouza, Emilio

    2010-11-01

    We studied the serotypes, mating-types, AFLP genotypes, and antifungal susceptibility of 58 Cryptococcus neoformans strains causing 56 episodes of cryptococcosis in 55 patients over an 18-year period in a single institution. The underlying conditions of the patients were classified as HIV infection (n = 48) or non-HIV-related immunodeficiency (n = 7). Serotype A (n = 34; 58.9%) predominated, but serotype AD was involved in 23.2% of episodes. Most of the episodes were caused by mating-type α (n = 41; 73.2%) or α/a strains (n = 12; 21.5%). The most common genotype was AFLP1 (n = 26; 44.8%), followed by AFLP3 (n = 21; 36.2%), and AFLP2 (n = 11; 19.0%). In two different patients, we showed the coexistence of different serotypes and/or genotypes in the same episode (AFLP1 and 3). The new triazoles voriconazole, posaconazole and isavuconazole showed high and similar antifungal activity (MICs ≤ 0.125 μg/ml). Fluconazole also had good antifungal activity, but two strains from patients with HIV-infections had an MIC of 16 μg/ml (3.4%). However, these two isolates remained very susceptible to the new triazoles (MICs ≤ 0.062 μg/ml). The remaining strains always showed MICs ≤ 8 μg/ml.

  14. Impact of the competition between mating types on the cultivation of Tuber melanosporum: Romeo and Juliet and the matter of space and time.

    PubMed

    Rubini, Andrea; Riccioni, Claudia; Belfiori, Beatrice; Paolocci, Francesco

    2014-04-01

    Major breakthroughs in our understanding of the life cycles of the symbiotic ascomycetes belonging to the genus Tuber have occurred over the last several years. A number of Tuber species produce edible fruiting bodies, known as truffles, that are marketed worldwide. A better understanding of the basic biological characteristics of Tuber spp. is likely to have tremendous practical relevance for their cultivation. Tuber melanosporum produces the most valuable black truffles and its genome has been recently sequenced. This species is now serving as a model for studying the biology of truffles. Here, we review recent progress in the understanding of sexual reproduction modalities in T. melanosporum. The practical relevance of these findings is outlined. In particular, the discoveries that T. melanosporum is heterothallic and that strains of different mating types compete to persist on the roots of host plants suggest that the spatial and temporal distributional patterns of strains of different mating types are key determinants of truffle fructification. The spatial segregation of the two mating types in areas where T. melanosporum occurs likely limits truffle production. Thus, host plant inoculation techniques and agronomic practices that might be pursued to manage T. melanosporum orchards with a balanced presence of the two mating partners are described.

  15. Evolutionary restoration of fertility in an interspecies hybrid yeast, by whole-genome duplication after a failed mating-type switch

    PubMed Central

    Ortiz-Merino, Raúl A.; Kuanyshev, Nurzhan; Braun-Galleani, Stephanie; Byrne, Kevin P.; Porro, Danilo; Branduardi, Paola

    2017-01-01

    Many interspecies hybrids have been discovered in yeasts, but most of these hybrids are asexual and can replicate only mitotically. Whole-genome duplication has been proposed as a mechanism by which interspecies hybrids can regain fertility, restoring their ability to perform meiosis and sporulate. Here, we show that this process occurred naturally during the evolution of Zygosaccharomyces parabailii, an interspecies hybrid that was formed by mating between 2 parents that differed by 7% in genome sequence and by many interchromosomal rearrangements. Surprisingly, Z. parabailii has a full sexual cycle and is genetically haploid. It goes through mating-type switching and autodiploidization, followed by immediate sporulation. We identified the key evolutionary event that enabled Z. parabailii to regain fertility, which was breakage of 1 of the 2 homeologous copies of the mating-type (MAT) locus in the hybrid, resulting in a chromosomal rearrangement and irreparable damage to 1 MAT locus. This rearrangement was caused by HO endonuclease, which normally functions in mating-type switching. With 1 copy of MAT inactivated, the interspecies hybrid now behaves as a haploid. Our results provide the first demonstration that MAT locus damage is a naturally occurring evolutionary mechanism for whole-genome duplication and restoration of fertility to interspecies hybrids. The events that occurred in Z. parabailii strongly resemble those postulated to have caused ancient whole-genome duplication in an ancestor of Saccharomyces cerevisiae. PMID:28510588

  16. The switching gene swi6 affects recombination and gene expression in the mating-type region of Schizosaccharomyces pombe.

    PubMed

    Lorentz, A; Heim, L; Schmidt, H

    1992-06-01

    The products of 11 switching (swi) genes are required for efficient mating-type (MT) switching in homothallic (h90) strains of Schizosaccharomyces pombe. The MT region of h90 comprises three cassette genes: the expression site mat1:1 and two silent loci, mat2:2 and mat3:3. Besides reducing MT switching, the swi6 mutation leads to deletions in the MT region caused by intrachromosomal cross-overs between two paired cassettes. These deletions only arise if DNA double-strand breaks are present at mat1:1, which initiate MT switching. Furthermore, swi6 allows meiotic recombination in the K region, a region of 16 kb between mat2:2 and mat3:3; in wild-type strains no recombination occurs in K. swi6 also allows the simultaneous expression of two different cassettes in the same haploid cell. Thus swi6 may have an influence on the general chromatin structure in the MT region.

  17. Co-expression of the mating-type genes involved in internuclear recognition is lethal in Podospora anserina.

    PubMed Central

    Coppin, E; Debuchy, R

    2000-01-01

    In the heterothallic filamentous fungus Podospora anserina, four mating-type genes encoding transcriptional factors have been characterized: FPR1 in the mat+ sequence and FMR1, SMR1, and SMR2 in the alternative mat- sequence. Fertilization is controlled by FPR1 and FMR1. After fertilization, male and female nuclei, which have divided in the same cell, form mat+/mat- pairs during migration into the ascogenous hyphae. Previous data indicate that the formation of mat+/mat- pairs is controlled by FPR1, FMR1, and SMR2. SMR1 was postulated to be necessary for initial development of ascogenous hyphae. In this study, we investigated the transcriptional control of the mat genes by seeking mat transcripts during the vegetative and sexual phase and fusing their promoter to a reporter gene. The data indicate that FMR1 and FPR1 are expressed in both mycelia and perithecia, whereas SMR1 and SMR2 are transcribed in perithecia. Increased or induced vegetative expression of the four mat genes has no effect when the recombined gene is solely in the wild-type strain. However, the combination of resident FPR1 with deregulated SMR2 and overexpressed FMR1 in the same nucleus is lethal. This lethality is suppressed by the expression of SMR1, confirming that SMR1 operates downstream of the other mat genes. PMID:10835389

  18. An external loop region of domain III of dengue virus type 2 envelope protein is involved in serotype-specific binding to mosquito but not mammalian cells.

    PubMed

    Hung, Jan-Jong; Hsieh, Meng-Ti; Young, Ming-Jer; Kao, Chuan-Liang; King, Chwan-Chuen; Chang, Wen

    2004-01-01

    Dengue virus (DV) is a flavivirus and infects mammalian cells through mosquito vectors. This study investigates the roles of domain III of DV type 2 envelope protein (EIII) in DV binding to the host cell. Recombinant EIII interferes with DV infection to BHK21 and C6/36 cells by blocking dengue virion adsorption to these cells. Inhibition of EIII on BHK21 cells was broad with no serotype specificity; however, inhibition of EIII on C6/36 cells was relatively serotype specific. Soluble heparin completely blocks binding of EIII to BHK21 cells, suggesting that domain III binds mainly to cell surface heparan sulfates. This suggestion is supported by the observation that EIII binds very weakly to gro2C and sog9 mutant mammalian cell lines that lack heparan sulfate. In contrast, heparin does not block binding of EIII to mosquito cells. Furthermore, a synthetic peptide that includes amino acids (aa) 380 to 389 of EIII, IGVEPGQLKL, inhibits binding of EIII to C6/36 but not BHK21 cells. This peptide corresponds to a lateral loop region on domain III of E protein, indicating a possible role of this loop in binding to mosquito cells. In summary, these results suggest that EIII plays an important role in binding of DV type 2 to host cells. In addition, EIII interacts with heparan sulfates when binding to BHK21 cells, and a loop region containing aa 380 to 389 of EIII may participate in DV type 2 binding to C6/36 cells.

  19. An External Loop Region of Domain III of Dengue Virus Type 2 Envelope Protein Is Involved in Serotype-Specific Binding to Mosquito but Not Mammalian Cells

    PubMed Central

    Hung, Jan-Jong; Hsieh, Meng-Ti; Young, Ming-Jer; Kao, Chuan-Liang; King, Chwan-Chuen; Chang, Wen

    2004-01-01

    Dengue virus (DV) is a flavivirus and infects mammalian cells through mosquito vectors. This study investigates the roles of domain III of DV type 2 envelope protein (EIII) in DV binding to the host cell. Recombinant EIII interferes with DV infection to BHK21 and C6/36 cells by blocking dengue virion adsorption to these cells. Inhibition of EIII on BHK21 cells was broad with no serotype specificity; however, inhibition of EIII on C6/36 cells was relatively serotype specific. Soluble heparin completely blocks binding of EIII to BHK21 cells, suggesting that domain III binds mainly to cell surface heparan sulfates. This suggestion is supported by the observation that EIII binds very weakly to gro2C and sog9 mutant mammalian cell lines that lack heparan sulfate. In contrast, heparin does not block binding of EIII to mosquito cells. Furthermore, a synthetic peptide that includes amino acids (aa) 380 to 389 of EIII, IGVEPGQLKL, inhibits binding of EIII to C6/36 but not BHK21 cells. This peptide corresponds to a lateral loop region on domain III of E protein, indicating a possible role of this loop in binding to mosquito cells. In summary, these results suggest that EIII plays an important role in binding of DV type 2 to host cells. In addition, EIII interacts with heparan sulfates when binding to BHK21 cells, and a loop region containing aa 380 to 389 of EIII may participate in DV type 2 binding to C6/36 cells. PMID:14671119

  20. Functional Characterization of MAT1-1-Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators▿†

    PubMed Central

    Klix, V.; Nowrousian, M.; Ringelberg, C.; Loros, J. J.; Dunlap, J. C.; Pöggeler, S.

    2010-01-01

    Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular basis of homothallism and the role of mating-type genes during fruiting-body development, we deleted each of the three genes, SmtA-1 (MAT1-1-1), SmtA-2 (MAT1-1-2), and SmtA-3 (MAT1-1-3), contained in the MAT1-1 part of the mating-type locus of the homothallic ascomycete species Sordaria macrospora. Phenotypic analysis of deletion mutants revealed that the PPF domain protein-encoding gene SmtA-2 is essential for sexual reproduction, whereas the α domain protein-encoding genes SmtA-1 and SmtA-3 play no role in fruiting-body development. By means of cross-species microarray analysis using Neurospora crassa oligonucleotide microarrays hybridized with S. macrospora targets and quantitative real-time PCR, we identified genes expressed under the control of SmtA-1 and SmtA-2. Both genes are involved in the regulation of gene expression, including that of pheromone genes. PMID:20435701

  1. A DTX/MATE-type transporter facilitates abscisic acid efflux and modulates ABA sensitivity and drought tolerance in Arabidopsis.

    PubMed

    Zhang, Haiwen; Zhu, Huifen; Pan, Yajun; Yu, Yuexuan; Luan, Sheng; Li, Legong

    2014-10-01

    Abscisic acid (ABA) regulates numerous physiological and developmental processes in plants. Recent studies identify intracellular ABA receptors, implicating the transport of ABA across cell membranes as crucial for ABA sensing and response. Here, we report that a DTX/Multidrug and Toxic Compound Extrusion (MATE) family member in Arabidopsis thaliana, AtDTX50, functions as an ABA efflux transporter. When expressed heterologously in both an Escherichia coli strain and Xenopus oocyte cells, AtDTX50 was found to facilitate ABA efflux. Furthermore, dtx50 mutant mesophyll cells preloaded with ABA released less ABA compared with the wild-type (WT). The AtDTX50 gene was expressed mainly in the vascular tissues and guard cells and its expression was strongly up-regulated by exogenous ABA. The AtDTX50::GFP fusion protein was localized predominantly to the plasma membrane. The dtx50 mutant plants were observed to be more sensitive to ABA in growth inhibition. In addition, compared with the WT, dtx50 mutant plants were more tolerant to drought with lower stomatal conductance, consistent with its function as an ABA efflux carrier in guard cells. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

  2. Mutations in XRS2 and RAD50 delay but do not prevent mating-type switching in Saccharomyces cerevisiae.

    PubMed Central

    Ivanov, E L; Sugawara, N; White, C I; Fabre, F; Haber, J E

    1994-01-01

    In Saccharomyces cerevisiae, a large number of genes in the RAD52 epistasis group has been implicated in the repair of chromosomal double-strand breaks and in both mitotic and meiotic homologous recombination. While most of these genes are essential for yeast mating-type (MAT) gene switching, neither RAD50 nor XRS2 is required to complete this specialized mitotic gene conversion process. Using a galactose-inducible HO endonuclease gene to initiate MAT switching, we have examined the effect of null mutations of RAD50 and of XRS2 on intermediate steps of this recombination event. Both rad50 and xrs2 mutants exhibit a marked delay in the completion of switching. Both mutations reduce the extent of 5'-to-3' degradation from the end of the HO-created double-strand break. The steps of initial strand invasion and new DNA synthesis are delayed by approximately 30 min in mutant cells. However, later events are still further delayed, suggesting that XRS2 and RAD50 affect more than one step in the process. In the rad50 xrs2 double mutant, the completion of MAT switching is delayed more than in either single mutant, without reducing the overall efficiency of the process. The XRS2 gene encodes an 854-amino-acid protein with no obvious similarity to the Rad50 protein or to any other protein in the database. Overexpression of RAD50 does not complement the defects in xrs2 or vice versa. Images PMID:8164689

  3. The mutator gene swi8 effects specific mutations in the mating-type region of Schizosaccharomyces pombe.

    PubMed

    Fleck, O; Rudolph, C; Albrecht, A; Lorentz, A; Schär, P; Schmidt, H

    1994-11-01

    The swi8+ gene of Schizosaccharomyces pombe appears to be involved in the termination step of copy synthesis during mating-type (MT) switching. Mutations in swi8 confer a general mutator phenotype and, in particular, generate specific mutations in the MT region. Sequencing of the MT cassettes of the h90 swi8-137 mutant revealed three altered sites. One is situated at the switching (smt) signal adjacent to the H1 homology box of the expression locus mat1:1. It reduces the rate of MT switching. The alteration at the smt signal arose frequently in other h90 swi8 strains and is probably caused by gene conversion in which the sequence adjacent to the H1 box of mat2:2 is used as template. This change might be generated during the process of MT switching when hybrid DNA formation is anomalously extended into the more heterologous region flanking the H1 homology box. In addition to the gene conversion at mat1:1, two mutations were found in the H3 homology boxes of the silent cassettes mat2:2 and mat3:3.

  4. The Mutator Gene Swi8 Effects Specific Mutations in the Mating-Type Region of Schizosaccharomyces Pombe

    PubMed Central

    Fleck, O.; Rudolph, C.; Albrecht, A.; Lorentz, A.; Schar, P.; Schmidt, H.

    1994-01-01

    The swi8(+) gene of Schizosaccharomyces pombe appears to be involved in the termination step of copy synthesis during mating-type (MT) switching. Mutations in swi8 confer a general mutator phenotype and, in particular, generate specific mutations in the MT region. Sequencing of the MT cassettes of the h(90) swi8-137 mutant revealed three altered sites. One is situated at the switching (smt) signal adjacent to the H1 homology box of the expression locus mat1:1. It reduces the rate of MT switching. The alteration at the smt signal arose frequently in other h(90) swi8 strains and is probably caused by gene conversion in which the sequence adjacent to the H1 box of mat2:2 is used as template. This change might be generated during the process of MT switching when hybrid DNA formation is anomalously extended into the more heterologous region flanking the H1 homology box. In addition to the gene conversion at mat1:1, two mutations were found in the H3 homology boxes of the silent cassettes mat2:2 and mat3:3. PMID:7851760

  5. Three additional linkage groups that repress transcription and meiotic recombination in the mating-type region of Schizosaccharomyces pombe.

    PubMed

    Thon, G; Cohen, A; Klar, A J

    1994-09-01

    The mating-type genes of Schizosaccharomyces pombe are found at three locations in the same chromosomal region. These genes are in an active configuration at the mat1 locus and in an inactive configuration at the mat2 and mat3 loci. The mechanism that represses transcription of mat2 and mat3 also inactivates other promoters introduced nearby and is accompanied by a block to meiotic recombination in the mat2-mat3 interval, suggesting that this mechanism involves a particular chromatin structure. We present evidence that the transcription and recombination blocks require three newly defined trans-acting loci, clr2, clr3 and clr4, in addition to the previously identified clr1, rik1 and swi6 loci. We also investigated the role of mat2 cis-acting sequences in silencing. Four cis-acting elements that repress mat2 in a plasmid context were previously identified. Deletion of two of these elements proved to have little effect in a chromosomal context. However, when combined with mutations in trans-acting genes, deletion of the same two elements greatly enhanced mat2 expression. The observed cumulative effects suggest a redundancy in the silencing mechanism.

  6. Three Additional Linkage Groups That Repress Transcription and Meiotic Recombination in the Mating-Type Region of Schizosaccharomyces Pombe

    PubMed Central

    Thon, G.; Cohen, A.; Klar, A. J.

    1994-01-01

    The mating-type genes of Schizosaccharomyces pombe are found at three locations in the same chromosomal region. These genes are in an active configuration at the mat1 locus and in an inactive configuration at the mat2 and mat3 loci. The mechanism that represses transcription of mat2 and mat3 also inactivates other promoters introduced nearby and is accompanied by a block to meiotic recombination in the mat2-mat3 interval, suggesting that this mechanism involves a particular chromatin structure. We present evidence that the transcription and recombination blocks require three newly defined trans-acting loci, clr2, clr3 and clr4, in addition to the previously identified clr1, rik1 and swi6 loci. We also investigated the role of mat2 cis-acting sequences in silencing. Four cis-acting elements that repress mat2 in a plasmid context were previously identified. Deletion of two of these elements proved to have little effect in a chromosomal context. However, when combined with mutations in trans-acting genes, deletion of the same two elements greatly enhanced mat2 expression. The observed cumulative effects suggest a redundancy in the silencing mechanism. PMID:8001791

  7. Flirting with disaster: short-term mating orientation and hostile sexism predict different types of sexual harassment.

    PubMed

    Diehl, Charlotte; Rees, Jonas; Bohner, Gerd

    2012-01-01

    We combine evolutionary and sociocultural accounts of sexual harassment, proposing that sexuality-related and hostility-related motives lead to different types of harassment. Specifically, men's short-term mating orientation (STMO) was hypothesized to predict only unwanted sexual attention but not gender harassment, whereas men's hostile sexism (HS) was hypothesized to predict both unwanted sexual attention and gender harassment. As part of an alleged computer-chat task, 100 male students could send sexualized personal remarks (representing unwanted sexual attention), sexist jokes (representing gender harassment), or nonharassing material to an attractive female target. Independently, participants' STMO, HS, and sexual harassment myth acceptance (SHMA) were assessed. Correlational and path analyses revealed that STMO specifically predicted unwanted sexual attention, whereas HS predicted both unwanted sexual attention and gender harassment. Furthermore, SHMA fully mediated the effect of HS on gender harassment, but did not mediate effects of STMO or HS on unwanted sexual attention. Results are discussed in relation to motivational explanations for sexual harassment and antiharassment interventions. © 2012 Wiley Periodicals, Inc.

  8. Divergence of the dengue virus type 2 Cosmopolitan genotype associated with two predominant serotype shifts between 1 and 2 in Surabaya, Indonesia, 2008-2014.

    PubMed

    Kotaki, Tomohiro; Yamanaka, Atsushi; Mulyatno, Kris Cahyo; Churrotin, Siti; Sucipto, Teguh Hari; Labiqah, Amaliah; Ahwanah, Nur Laila Fitriati; Soegijanto, Soegeng; Kameoka, Masanori; Konishi, Eiji

    2016-01-01

    Indonesia is one of the biggest dengue endemic countries, and, thus, is an important place to investigate the evolution of dengue virus (DENV). We have continuously isolated DENV in Surabaya, the second biggest city in Indonesia, since 2008. We previously reported sequential changes in the predominant serotype from DENV type 2 (DENV-2) to DENV type 1 (DENV-1) in November 2008 and from DENV-1 to DENV-2 in July 2013. The predominance of DENV-2 continued in 2014, but not in 2015. We herein phylogenetically investigated DENV-2 transitions in Surabaya between 2008 and 2014 to analyze the divergence and evolution of DENV-2 concomitant with serotype shifts. All DENV-2 isolated in Surabaya were classified into the Cosmopolitan genotype, and further divided into 6 clusters. Clusters 1-3, dominated by Surabaya strains, were defined as the "Surabaya lineage". Clusters 4-6, dominated by strains from Singapore, Malaysia, and many parts of Indonesia, were the "South East Asian lineage". The most recent common ancestor of these strains existed in 1988, coinciding with the time that an Indonesian dengue outbreak took place. Cluster 1 appeared to be unique because no other DENV-2 isolate was included in this cluster. The predominance of DENV-2 in 2008 and 2013-14 were caused by cluster 1, whereas clusters 2 and 3 sporadically emerged in 2011 and 2012. The characteristic amino acids of cluster 1, E-170V and E-282Y, may be responsible for its prevalence in Surabaya. No amino acid difference was observed in the envelope region between strains in 2008 and 2013-14, suggesting that the re-emergence of DENV-2 in Surabaya was due to the loss or decrease of herd immunity in the 5-year period when DENV-2 subsided. The South East Asian lineage primarily emerged in Surabaya in 2014, probably imported from other parts of Indonesia or foreign countries. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Blind comparison of traditional serotyping with three multiplex PCRs for the identification of Salmonella serotypes.

    PubMed

    Herrera-León, Silvia; Ramiro, Raquel; Arroyo, Margarita; Díez, Rosa; Usera, Miguel Angel; Echeita, Maria Aurora

    2007-03-01

    Salmonella serotypes are defined on the basis of somatic (O) antigens which define the serogroup and flagellar (H) factor antigens, both of which are present in the cell wall of Salmonella. Most Salmonella organisms alternatively express phase-1 or phase-2 flagellar antigens encoded by fliC and fljB genes, respectively. Our group previously published two multiplex PCRs for distinguishing the most common first- and second-phase antigens. In this paper we describe a third multiplex PCR to identify the most common serogroups (O:B; O:C1; O:C2; O:D and O:E). The combination of these three PCRs enabled us to completely serotype organisms belonging to the Salmonella species. This multiplex PCR includes 10 primers. A total of 67 Salmonella strains belonging to 32 different serotypes were tested. Each strain generated one serogroup-specific fragment ranging between 162 and 615bp. Twenty-eight strains belonging to 21 serotypes, with a serogroup different from those tested in this work, did not generate any fragments. To compare molecular serotyping with traditional serotyping, 500 strains, received according to the order of arrival in the laboratory, were serotyped using both methods. The three multiplex PCRs were able to serotype 84.6% of the tested strains. This method was found to be very helpful in our laboratory as an alternative method for typing strains causing outbreaks, and it can be used to supplement conventional serotyping, since it is also applicable to motionless and rough strains.

  10. Identification of Uhp1, a ubiquitinated histone-like protein, as a target/mediator of Rhp6 in mating-type silencing in fission yeast.

    PubMed

    Naresh, Alpana; Saini, Sharanjot; Singh, Jagmohan

    2003-03-14

    Mating-type silencing in Schizosaccharomyces pombe is brought about by cooperative interactions between cis-acting DNA sequences flanking mat2P and mat3M and the trans-acting factors, namely Swi6, Clr1-Clr4, Clr6, and Rik1. In addition, DNA repair gene rhp6, which plays a role in post-replication DNA repair and ubiquitination of proteins including histones, is also involved in silencing, albeit in a unique way; its effect on silencing and chromatin structure of the donor loci is dependent on their switching competence. Earlier, we hypothesized the existence of a mediator of Rhp6 that plays a role in reestablishment of the chromatin structure coincidentally with DNA replication associated with mating-type switching. Here we report the identification of a 22-kDa protein as an in vivo target and mediator of Rhp6 in mating-type silencing. The level of this protein is greatly elevated in sng1-1/rhp6(-) mutant and rhp6Delta as compared with wild type strain. Both the deletion and overexpression of the gene encoding this protein elicit switching-dependent loss of silencing. Furthermore, the 22-kDa protein undergoes Rhp6-dependent multiubiquitination and associates with mat2 locus during S phase in wild type cells. Interestingly, it contains a histone-fold motif similar to that of histone H2A, and like histone H2A, it interacts strongly with histone H2B in vitro. These results indicate that the 22-kDa protein, renamed as the ubiquitinated histone-like protein Uhp1, is an in vivo target/mediator of Rhp6 in silencing. Thus, regulation of association of Uhp1 with chromatin and ubiquitination followed by degradation may play a role in reestablishment of inactive chromatin structure at the silent mating-type loci.

  11. A MADS box protein interacts with a mating-type protein and is required for fruiting body development in the homothallic ascomycete Sordaria macrospora.

    PubMed

    Nolting, Nicole; Pöggeler, Stefanie

    2006-07-01

    MADS box transcription factors control diverse developmental processes in plants, metazoans, and fungi. To analyze the involvement of MADS box proteins in fruiting body development of filamentous ascomycetes, we isolated the mcm1 gene from the homothallic ascomycete Sordaria macrospora, which encodes a putative homologue of the Saccharomyces cerevisiae MADS box protein Mcm1p. Deletion of the S. macrospora mcm1 gene resulted in reduced biomass, increased hyphal branching, and reduced hyphal compartment length during vegetative growth. Furthermore, the S. macrospora Deltamcm1 strain was unable to produce fruiting bodies or ascospores during sexual development. A yeast two-hybrid analysis in conjugation with in vitro analyses demonstrated that the S. macrospora MCM1 protein can interact with the putative transcription factor SMTA-1, encoded by the S. macrospora mating-type locus. These results suggest that the S. macrospora MCM1 protein is involved in the transcriptional regulation of mating-type-specific genes as well as in fruiting body development.

  12. Large-Scale Introgression Shapes the Evolution of the Mating-Type Chromosomes of the Filamentous Ascomycete Neurospora tetrasperma

    PubMed Central

    Menkis, Audrius; Whittle, Carrie A.; Andersson, Siv G. E.; Johannesson, Hanna

    2012-01-01

    The significance of introgression as an evolutionary force shaping natural populations is well established, especially in animal and plant systems. However, the abundance and size of introgression tracts, and to what degree interspecific gene flow is the result of adaptive processes, are largely unknown. In this study, we present medium coverage genomic data from species of the filamentous ascomycete Neurospora, and we use comparative genomics to investigate the introgression landscape at the genomic level in this model genus. We revealed one large introgression tract in each of the three investigated phylogenetic lineages of Neurospora tetrasperma (sizes of 5.6 Mbp, 5.2 Mbp, and 4.1 Mbp, respectively). The tract is located on the chromosome containing the locus conferring sexual identity, the mating-type (mat) chromosome. The region of introgression is confined to the region of suppressed recombination and is found on one of the two mat chromosomes (mat a). We used Bayesian concordance analyses to exclude incomplete lineage sorting as the cause for the observed pattern, and multilocus genealogies from additional species of Neurospora show that the introgression likely originates from two closely related, freely recombining, heterothallic species (N. hispaniola and N. crassa/N. perkinsii). Finally, we investigated patterns of molecular evolution of the mat chromosome in Neurospora, and we show that introgression is correlated with reduced level of molecular degeneration, consistent with a shorter time of recombination suppression. The chromosome specific (mat) and allele specific (mat a) introgression reported herein comprise the largest introgression tracts reported to date from natural populations. Furthermore, our data contradicts theoretical predictions that introgression should be less likely on sex-determining chromosomes. Taken together, the data presented herein advance our general understanding of introgression as a force shaping eukaryotic genomes. PMID

  13. Fine-scale spatial genetic structure of the black truffle (Tuber melanosporum) investigated with neutral microsatellites and functional mating type genes.

    PubMed

    Murat, Claude; Rubini, Andrea; Riccioni, Claudia; De la Varga, Herminia; Akroume, Emila; Belfiori, Beatrice; Guaragno, Marco; Le Tacon, François; Robin, Christophe; Halkett, Fabien; Martin, Francis; Paolocci, Francesco

    2013-07-01

    The genetic structure of ectomycorrhizal (ECM) fungal populations results from both vegetative and sexual propagation. In this study, we have analysed the spatial genetic structure of Tuber melanosporum populations, a heterothallic ascomycete that produces edible fruit bodies. Ectomycorrhizas from oaks and hazels from two orchards were mapped and genotyped using simple sequence repeat markers and the mating type locus. The distribution of the two T. melanosporum mating types was also monitored in the soil. In one orchard, the genetic profiles of the ascocarps were compared with those of the underlying mycorrhizas. A pronounced spatial genetic structure was found. The maximum genet sizes were 2.35 and 4.70 m in the two orchards, with most manifesting a size < 1 m. Few genets persisted throughout two seasons. A nonrandom distribution pattern of the T. melanosporum was observed, resulting in field patches colonized by genets that shared the same mating types. Our findings suggest that competition occurs between genets and provide basic information on T. melanosporum propagation patterns that are relevant for the management of productive truffle orchards.

  14. Comparative Genomics of the Ectomycorrhizal Sister Species Rhizopogon vinicolor and Rhizopogon vesiculosus (Basidiomycota: Boletales) Reveals a Divergence of the Mating Type B Locus

    PubMed Central

    Mujic, Alija Bajro; Kuo, Alan; Tritt, Andrew; Lipzen, Anna; Chen, Cindy; Johnson, Jenifer; Sharma, Aditi; Barry, Kerrie; Grigoriev, Igor V.; Spatafora, Joseph W.

    2017-01-01

    Divergence of breeding system plays an important role in fungal speciation. Ectomycorrhizal fungi, however, pose a challenge for the study of reproductive biology because most cannot be mated under laboratory conditions. To overcome this barrier, we sequenced the draft genomes of the ectomycorrhizal sister species Rhizopogon vinicolor Smith and Zeller and R. vesiculosus Smith and Zeller (Basidiomycota, Boletales)—the first genomes available for Basidiomycota truffles—and characterized gene content and organization surrounding their mating type loci. Both species possess a pair of homeodomain transcription factor homologs at the mating type A-locus as well as pheromone receptor and pheromone precursor homologs at the mating type B-locus. Comparison of Rhizopogon genomes with genomes from Boletales, Agaricales, and Polyporales revealed synteny of the A-locus region within Boletales, but several genomic rearrangements across orders. Our findings suggest correlation between gene content at the B-locus region and breeding system in Boletales with tetrapolar species possessing more diverse gene content than bipolar species. Rhizopogon vinicolor possesses a greater number of B-locus pheromone receptor and precursor genes than R. vesiculosus, as well as a pair of isoprenyl cysteine methyltransferase genes flanking the B-locus compared to a single copy in R. vesiculosus. Examination of dikaryotic single nucleotide polymorphisms within genomes revealed greater heterozygosity in R. vinicolor, consistent with increased rates of outcrossing. Both species possess the components of a heterothallic breeding system with R. vinicolor possessing a B-locus region structure consistent with tetrapolar Boletales and R. vesiculosus possessing a B-locus region structure intermediate between bipolar and tetrapolar Boletales. PMID:28450370

  15. Grapevine MATE-Type Proteins Act as Vacuolar H+-Dependent Acylated Anthocyanin Transporters1[W][OA

    PubMed Central

    Gomez, Camila; Terrier, Nancy; Torregrosa, Laurent; Vialet, Sandrine; Fournier-Level, Alexandre; Verriès, Clotilde; Souquet, Jean-Marc; Mazauric, Jean-Paul; Klein, Markus; Cheynier, Véronique; Ageorges, Agnès

    2009-01-01

    In grapevine (Vitis vinifera), anthocyanins are responsible for most of the red, blue, and purple pigmentation found in the skin of berries. In cells, anthocyanins are synthesized in the cytoplasm and accumulated into the vacuole. However, little is known about the transport of these compounds through the tonoplast. Recently, the sequencing of the grapevine genome allowed us to identify genes encoding proteins with high sequence similarity to the Multidrug And Toxic Extrusion (MATE) family. Among them, we selected two genes as anthocyanin transporter candidates and named them anthoMATE1 (AM1) and AM3. The expression of both genes was mainly fruit specific and concomitant with the accumulation of anthocyanin pigment. Subcellular localization assays in grapevine hairy roots stably transformed with AM1∷ or AM3∷green fluorescent protein fusion protein revealed that AM1 and AM3 are primarily localized to the tonoplast. Yeast vesicles expressing anthoMATEs transported acylated anthocyanins in the presence of MgATP. Inhibitor studies demonstrated that AM1 and AM3 proteins act in vitro as vacuolar H+-dependent acylated anthocyanin transporters. By contrast, under our experimental conditions, anthoMATEs could not transport malvidin 3-O-glucoside or cyanidin 3-O-glucoside, suggesting that the acyl conjugation was essential for the uptake. Taken together, these results provide evidence that in vitro the two grapevine AM1 and AM3 proteins mediate specifically acylated anthocyanin transport. PMID:19297587

  16. Cost of mating and insemination capacity of a genetically modified mosquito Aedes aegypti OX513A compared to its wild type counterpart.

    PubMed

    Bargielowski, Irka; Alphey, Luke; Koella, Jacob C

    2011-01-01

    The idea of implementing genetics-based insect control strategies modelled on the traditional SIT is becoming increasingly popular. In this paper we compare a genetically modified line of Aedes aegypti carrying a tetracycline repressible, lethal positive feedback system (OX513A) with its wild type counterpart with respect to their insemination capacities and the cost of courtship and mating. Genetically modified males inseminated just over half as many females as the wild type males during their lifetime. Providing days of rest from mating had no significant effect on the total number of females inseminated by males of either line, but it did increase their longevity. Producing sperm had a low cost in terms of energy investment; the cost of transferring this sperm to a receptive female was much higher. Continued mating attempts with refractory females suggest that males could not identify refractory females before investing substantial energy in courtship. Although over a lifetime OX513A males inseminated fewer females, the number of females inseminated over the first three days, was similar between males of the two lines, suggesting that the identified cost of RIDL may have little impact on the outcome of SIT-based control programmes with frequent releases of the genetically modified males.

  17. Cost of Mating and Insemination Capacity of a Genetically Modified Mosquito Aedes aegypti OX513A Compared to Its Wild Type Counterpart

    PubMed Central

    Bargielowski, Irka; Alphey, Luke; Koella, Jacob C.

    2011-01-01

    The idea of implementing genetics-based insect control strategies modelled on the traditional SIT is becoming increasingly popular. In this paper we compare a genetically modified line of Aedes aegypti carrying a tetracycline repressible, lethal positive feedback system (OX513A) with its wild type counterpart with respect to their insemination capacities and the cost of courtship and mating. Genetically modified males inseminated just over half as many females as the wild type males during their lifetime. Providing days of rest from mating had no significant effect on the total number of females inseminated by males of either line, but it did increase their longevity. Producing sperm had a low cost in terms of energy investment; the cost of transferring this sperm to a receptive female was much higher. Continued mating attempts with refractory females suggest that males could not identify refractory females before investing substantial energy in courtship. Although over a lifetime OX513A males inseminated fewer females, the number of females inseminated over the first three days, was similar between males of the two lines, suggesting that the identified cost of RIDL may have little impact on the outcome of SIT-based control programmes with frequent releases of the genetically modified males. PMID:22022518

  18. Evaluation of Molecular Methods for Serotyping Shigella flexneri

    PubMed Central

    Gentle, Amy; Ashton, Philip M.; Dallman, Timothy J.

    2016-01-01

    Shigella flexneri can be phenotypically serotyped using antisera raised to type-specific somatic antigens and group factor antigens and genotypically serotyped using PCR targeting O-antigen synthesis or modification genes. The aim of this study was to evaluate a real-time PCR for serotyping S. flexneri and to use whole-genome sequencing (WGS) to investigate the phenotypic and genotypic serotype identifications. Of the 244 cultures tested retrospectively, 226 (92.6%) had concordant results between phenotypic serotyping and PCR. Seventy of the 244 isolates (including 15 of the 18 isolates where a serotype-PCR mismatch was identified) were whole-genome sequenced, and the serotype was derived from the genome. Discrepant results between the phenotypic and genotypic tests were attributed to insertions/deletions or point mutations identified in O-antigen synthesis or modification genes, rendering them dysfunctional; inconclusive serotyping results due to nonspecific cross-reactions; or novel genotypes. Phylogenetic analysis of the WGS data indicated that the serotype, regardless of whether it was phenotypically or genotypically determined, was a weak predictor of phylogenetic relationships between strains of S. flexneri. WGS data provided both genome-derived serotyping, thus supporting backward compatibility with historical data and facilitating data exchange in the community, and more robust and discriminatory typing at the single-nucleotide-polymorphism level. PMID:26984974

  19. Foot-and-mouth disease vaccine potency testing: the influence of serotype, type of adjuvant, valency, fractionation method, and virus culture on the dose-response curve in cattle.

    PubMed

    Jamal, Syed M; Bouma, Annemarie; van den Broek, Jan; Stegeman, Arjan; Chénard, Gilles; Dekker, Aldo

    2008-11-25

    The aim of this study was to determine a relationship between vaccine potency (amount of PD50 per dose) and fraction of clinically protected cattle following homologous challenge with infectious foot-and-mouth disease (FMD) virus, and to determine the effect of method of fractionation, serotype, type of adjuvant, valency and type of virus culture on the dose-response curve. Data from 297 potency tests of FMD vaccines, comprising 4004 vaccinated cattle, performed at the FMD vaccine production facility in the Netherlands, were used for the present study. A generalised linear mixed effect model was used to analyse the results. Our study showed that the relation between FMD vaccine potency and fraction protected was also affected by the serotype and type of adjuvant. No common level of protection could be assigned to all FMD vaccines with the same amount of PD50 per dose, this information is essential when designing a new standard FMD vaccines control.

  20. Improved Detection of Nasopharyngeal Cocolonization by Multiple Pneumococcal Serotypes by Use of Latex Agglutination or Molecular Serotyping by Microarray▿†

    PubMed Central

    Turner, Paul; Hinds, Jason; Turner, Claudia; Jankhot, Auscharee; Gould, Katherine; Bentley, Stephen D.; Nosten, François; Goldblatt, David

    2011-01-01

    Identification of Streptococcus pneumoniae in the nasopharynx is critical for an understanding of transmission, estimates of vaccine efficacy, and possible replacement disease. Conventional nasopharyngeal swab (NPS) culture and serotyping (the WHO protocol) is likely to underestimate multiple-serotype carriage. We compared the WHO protocol with methods aimed at improving cocolonization detection. One hundred twenty-five NPSs from an infant pneumococcal-carriage study, containing ≥1 serotype by WHO culture, were recultured in duplicate. A sweep of colonies from one plate culture was serotyped by latex agglutination. DNA extracted from the second plate was analyzed by S. pneumoniae molecular-serotyping microarray. Multiple serotypes were detected in 11.2% of the swabs by WHO culture, 43.2% by sweep serotyping, and 48.8% by microarray. Sweep and microarray were more likely to detect multiple serotypes than WHO culture (P < 0.0001). Cocolonization detection rates were similar between microarray and sweep, but the microarray identified the greatest number of serotypes. A common serogroup type was identified in 95.2% of swabs by all methods. WHO methodology significantly underestimates multiple-serotype carriage compared to these alternate methods. Sweep serotyping is cost-effective and field deployable but may fail to detect serotypes at low abundance, whereas microarray serotyping is more costly and technology dependent but may detect these additional minor carried serotypes. PMID:21411589

  1. Heteroduplex formation and mismatch repair of the "stuck" mutation during mating-type switching in Saccharomyces cerevisiae.

    PubMed Central

    Ray, B L; White, C I; Haber, J E

    1991-01-01

    We sequenced two alleles of the MATa locus of Saccharomyces cerevisiae that reduce homothallic switching and confer viability to HO rad52 strains. Both the MATa-stk (J. E. Haber, W. T. Savage, S. M. Raposa, B. Weiffenbach, and L. B. Rowe, Proc. Natl. Acad. Sci. USA 77:2824-2828, 1980) and MATa-survivor (R. E. Malone and D. Hyman, Curr. Genet. 7:439-447, 1983) alleles result from a T----A base change at position Z11 of the MAT locus. These strains also contain identical base substitutions at HMRa, so that the mutation is reintroduced when MAT alpha switches to MATa. Mating-type switching in a MATa-stk strain relative to a MATa Z11T strain is reduced at least 50-fold but can be increased by expression of HO from a galactose-inducible promoter. We confirmed by Southern analysis that the Z11A mutation reduced the efficiency of double-strand break formation compared with the Z11T variant; the reduction was more severe in MAT alpha than in MATa. In MAT alpha, the Z11A mutation also creates a mat alpha 1 (sterile) mutation that distinguishes switches of MATa-stk to either MAT alpha or mat alpha 1-stk. Pedigree analysis of cells induced to switch in G1 showed that MATa-stk switched frequently (23% of the time) to produce one mat alpha 1-stk and one MAT alpha progeny. This postswitching segregation suggests that Z11 was often present in heteroduplex DNA that was not mismatch repaired. When mismatch repair was prevented by deletion of the PMS1 gene, there was an increase in the proportion of mat alpha 1-stk/MAT alpha sectors (59%) and in pairs of switched cells that both retained the stk mutation (27%). We conclude that at least one strand of DNA only 4 bp from the HO cut site is not degraded in most of the gene conversion events that accompany MAT switching. Images PMID:1922052

  2. Heteroduplex formation and mismatch repair of the "stuck" mutation during mating-type switching in Saccharomyces cerevisiae.

    PubMed

    Ray, B L; White, C I; Haber, J E

    1991-10-01

    We sequenced two alleles of the MATa locus of Saccharomyces cerevisiae that reduce homothallic switching and confer viability to HO rad52 strains. Both the MATa-stk (J. E. Haber, W. T. Savage, S. M. Raposa, B. Weiffenbach, and L. B. Rowe, Proc. Natl. Acad. Sci. USA 77:2824-2828, 1980) and MATa-survivor (R. E. Malone and D. Hyman, Curr. Genet. 7:439-447, 1983) alleles result from a T----A base change at position Z11 of the MAT locus. These strains also contain identical base substitutions at HMRa, so that the mutation is reintroduced when MAT alpha switches to MATa. Mating-type switching in a MATa-stk strain relative to a MATa Z11T strain is reduced at least 50-fold but can be increased by expression of HO from a galactose-inducible promoter. We confirmed by Southern analysis that the Z11A mutation reduced the efficiency of double-strand break formation compared with the Z11T variant; the reduction was more severe in MAT alpha than in MATa. In MAT alpha, the Z11A mutation also creates a mat alpha 1 (sterile) mutation that distinguishes switches of MATa-stk to either MAT alpha or mat alpha 1-stk. Pedigree analysis of cells induced to switch in G1 showed that MATa-stk switched frequently (23% of the time) to produce one mat alpha 1-stk and one MAT alpha progeny. This postswitching segregation suggests that Z11 was often present in heteroduplex DNA that was not mismatch repaired. When mismatch repair was prevented by deletion of the PMS1 gene, there was an increase in the proportion of mat alpha 1-stk/MAT alpha sectors (59%) and in pairs of switched cells that both retained the stk mutation (27%). We conclude that at least one strand of DNA only 4 bp from the HO cut site is not degraded in most of the gene conversion events that accompany MAT switching.

  3. Regulation of budding yeast mating-type switching donor preference by the FHA domain of Fkh1.

    PubMed

    Li, Jin; Coïc, Eric; Lee, Kihoon; Lee, Cheng-Sheng; Kim, Jung-Ae; Wu, Qiuqin; Haber, James E

    2012-01-01

    During Saccharomyces cerevisiae mating-type switching, an HO endonuclease-induced double-strand break (DSB) at MAT is repaired by recombining with one of two donors, HMLα or HMRa, located at opposite ends of chromosome III. MATa cells preferentially recombine with HMLα; this decision depends on the Recombination Enhancer (RE), located about 17 kb to the right of HML. In MATα cells, HML is rarely used and RE is bound by the MATα2-Mcm1 corepressor, which prevents the binding of other proteins to RE. In contrast, in MATa cells, RE is bound by multiple copies of Fkh1 and a single copy of Swi4/Swi6. We report here that, when RE is replaced with four LexA operators in MATa cells, 95% of cells use HMR for repair, but expression of a LexA-Fkh1 fusion protein strongly increases HML usage. A LexA-Fkh1 truncation, containing only Fkh1's phosphothreonine-binding FHA domain, restores HML usage to 90%. A LexA-FHA-R80A mutant lacking phosphothreonine binding fails to increase HML usage. The LexA-FHA fusion protein associates with chromatin in a 10-kb interval surrounding the HO cleavage site at MAT, but only after DSB induction. This association occurs even in a donorless strain lacking HML. We propose that the FHA domain of Fkh1 regulates donor preference by physically interacting with phosphorylated threonine residues created on proteins bound near the DSB, thus positioning HML close to the DSB at MAT. Donor preference is independent of Mec1/ATR and Tel1/ATM checkpoint protein kinases but partially depends on casein kinase II. RE stimulates the strand invasion step of interchromosomal recombination even for non-MAT sequences. We also find that when RE binds to the region near the DSB at MATa then Mec1 and Tel1 checkpoint kinases are not only able to phosphorylate histone H2A (γ-H2AX) around the DSB but can also promote γ-H2AX spreading around the RE region.

  4. Regulation of Budding Yeast Mating-Type Switching Donor Preference by the FHA Domain of Fkh1

    PubMed Central

    Lee, Kihoon; Lee, Cheng-Sheng; Kim, Jung-Ae; Wu, Qiuqin; Haber, James E.

    2012-01-01

    During Saccharomyces cerevisiae mating-type switching, an HO endonuclease-induced double-strand break (DSB) at MAT is repaired by recombining with one of two donors, HMLα or HMR a, located at opposite ends of chromosome III. MAT a cells preferentially recombine with HMLα; this decision depends on the Recombination Enhancer (RE), located about 17 kb to the right of HML. In MATα cells, HML is rarely used and RE is bound by the MATα2-Mcm1 corepressor, which prevents the binding of other proteins to RE. In contrast, in MAT a cells, RE is bound by multiple copies of Fkh1 and a single copy of Swi4/Swi6. We report here that, when RE is replaced with four LexA operators in MAT a cells, 95% of cells use HMR for repair, but expression of a LexA-Fkh1 fusion protein strongly increases HML usage. A LexA-Fkh1 truncation, containing only Fkh1's phosphothreonine-binding FHA domain, restores HML usage to 90%. A LexA-FHA-R80A mutant lacking phosphothreonine binding fails to increase HML usage. The LexA-FHA fusion protein associates with chromatin in a 10-kb interval surrounding the HO cleavage site at MAT, but only after DSB induction. This association occurs even in a donorless strain lacking HML. We propose that the FHA domain of Fkh1 regulates donor preference by physically interacting with phosphorylated threonine residues created on proteins bound near the DSB, thus positioning HML close to the DSB at MAT. Donor preference is independent of Mec1/ATR and Tel1/ATM checkpoint protein kinases but partially depends on casein kinase II. RE stimulates the strand invasion step of interchromosomal recombination even for non-MAT sequences. We also find that when RE binds to the region near the DSB at MAT a then Mec1 and Tel1 checkpoint kinases are not only able to phosphorylate histone H2A (γ-H2AX) around the DSB but can also promote γ-H2AX spreading around the RE region. PMID:22496671

  5. Genome sequencing and characterization of an extensively drug-resistant sequence type 111 serotype O12 hospital outbreak strain of Pseudomonas aeruginosa.

    PubMed

    Witney, A A; Gould, K A; Pope, C F; Bolt, F; Stoker, N G; Cubbon, M D; Bradley, C R; Fraise, A; Breathnach, A S; Butcher, P D; Planche, T D; Hinds, J

    2014-10-01

    A series of extensively drug-resistant isolates of Pseudomonas aeruginosa from two outbreaks in UK hospitals were characterized by whole genome sequencing (WGS). Although these isolates were resistant to antibiotics other than colistin, we confirmed that they are still sensitive to disinfectants. The sequencing confirmed that isolates in the larger outbreak were serotype O12, and also revealed that they belonged to sequence type ST111, which is a major epidemic strain of P. aeruginosa throughout Europe. As this is the first reported sequence of an ST111 strain, the genome was examined in depth, focusing particularly on antibiotic resistance and potential virulence genes, and on the reported regions of genome plasticity. High degrees of sequence similarity were discovered between outbreak isolates collected from recently infected patients, isolates from sinks, an isolate from the sewer, and a historical isolate, suggesting that the ST111 strain has been endemic in the hospital for many years. The ability to translate easily from outbreak investigation to detailed genome biology by use of the same data demonstrates the flexibility of WGS application in a clinical setting. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

  6. An Equine Herpesvirus Type 1 (EHV-1) Expressing VP2 and VP5 of Serotype 8 Bluetongue Virus (BTV-8) Induces Protection in a Murine Infection Model

    PubMed Central

    Ma, Guanggang; Eschbaumer, Michael; Said, Abdelrahman; Hoffmann, Bernd; Beer, Martin; Osterrieder, Nikolaus

    2012-01-01

    Bluetongue virus (BTV) can infect most species of domestic and wild ruminants causing substantial morbidity and mortality and, consequently, high economic losses. In 2006, an epizootic of BTV serotype 8 (BTV-8) started in northern Europe that caused significant disease in cattle and sheep before comprehensive vaccination was introduced two years later. Here, we evaluate the potential of equine herpesvirus type 1 (EHV-1), an alphaherpesvirus, as a novel vectored DIVA (differentiating infected from vaccinated animals) vaccine expressing VP2 of BTV-8 alone or in combination with VP5. The EHV-1 recombinant viruses stably expressed the transgenes and grew with kinetics that were identical to those of parental virus in vitro. After immunization of mice, a BTV-8-specific neutralizing antibody response was elicited. In a challenge experiment using a lethal dose of BTV-8, 100% of interferon-receptor-deficient (IFNAR−/−) mice vaccinated with the recombinant EHV-1 carrying both VP2 and VP5, but not VP2 alone, survived. VP7 was not included in the vectored vaccines and was successfully used as a DIVA marker. In summary, we show that EHV-1 expressing BTV-8 VP2 and VP5 is capable of eliciting a protective immune response that is distinguishable from that after infection and as such may be an alternative for BTV vaccination strategies in which DIVA compatibility is of importance. PMID:22511939

  7. Temporal distribution of human rotavirus serotypes 1,2,3, and 4 in Venezuelan children with gastroenteritis during 1979-1989.

    PubMed

    White, L; García, D; Boher, Y; Blanco, M; Pérez, M; Romer, H; Flores, J; Pérez-Schael, I

    1991-06-01

    The temporal distribution and clinical severity of rotavirus VP7 serotypes 1, 2, 3, and 4 recovered from 427 Venezuelan children with acute gastroenteritis over a period of 11 years were studied. Rotavirus VP7 serotype was established by ELISA serotyping in 298 (69.78%) of the specimens while the serotype of the remaining 129 (30.21%) samples could not be determined. Of the specimens typed, 85 (19.90% of the total) were serotype 1, 43 (10.07%) were serotype 2, 105 (24.59%) were serotype 3, and 65 (15.22%) were serotype 4. Yearly changes in the frequency of individual serotypes were observed. The predominance of a single serotype with minor contribution from others was noted every year. In this study, serotype 1 appears to induce a less severe illness in comparison with serotypes 2, 3, and 4. No apparent association between the proportion of each serotype and the children's age were found.

  8. Mating competitiveness and life-table comparisons between transgenic and Indian wild-type Aedes aegypti L.

    PubMed

    Patil, Prabhakargouda B; Reddy, B P Niranjan; Gorman, Kevin; Reddy, K V Seshu; Barwale, Shirish R; Zehr, Usha B; Nimmo, Derric; Naish, Neil; Alphey, Luke

    2015-07-01

    OX513A is a genetically engineered strain of Aedes aegypti carrying a repressible, dominantly inherited transgene that confers lethality in immature heterozygous progeny. Released male OX513A adults have proven to be effective for the localised suppression of wild Ae. aegypti, highlighting its potential in vector control. Mating and life-table assessments were used to compare OX513A with reared Ae. aegypti strains collected from New Delhi and Aurangabad regions in India. Mating proportions of New Delhi females versus males of OX513A or New Delhi strains were 0.52 and 0.48 respectively, indicating no discrimination by females against either strain, and males of both strains were equally competitive. Developmental time from first instar to adult emergence was significantly longer for OX513A (10.7 ± 0.04 days) than for New Delhi (9.4 ± 0.04 days) and Aurangabad strains (9.1 ± 0.04 days). Differences in mean longevities, female reproductive parameters and population growth parameters between the strains were non-significant. The laboratory study demonstrates that only minor life-table variations of limited biological relevance exist between OX513A and Indian Ae. aegypti populations, and males had equal potential for mating competitiveness. Thus, results support the OX513A strain as a suitable candidate for continued evaluation towards sustainable management of Ae. aegypti populations in India. © 2014 Society of Chemical Industry.

  9. Design of Two Multiplex PCR Assays for Serotyping Shigella flexneri.

    PubMed

    van der Ploeg, Claudia A; Rogé, Ariel D; Bordagorría, Ximena L; de Urquiza, Maria T; Celi Castillo, Ana B; Bruno, Susana B

    2017-10-10

    Shigella flexneri is a major health problem in developing countries. There are 19 serotypes recognized based on O-antigen structure and its typing is important for epidemiological purposes. However, the diversity of serotypes and the difficulties presented by phenotypic serotyping, for example, unavailable antisera for less common antigens, require the implementation of molecular techniques. In this study, we developed two multiplex PCR assays targeting the O-antigen synthesis genes and the O-antigen modification genes, for the rapid identification of S. flexneri serotypes 1/7, 2, 4, 5, and 6 (PCR A) and serotype 7 and group antigenic factors (3,4; 6; 7,8; E1037) (PCR B). A total of 73 S. flexneri strains representing 18 serotypes, except serotype 1d, were used in the study. Specific amplification patterns were obtained for each of the different serotypes. All strains tested had concordant results with phenotypic and genotypic serotyping; therefore, its implementation in the microbiology clinical laboratory will significantly improve S. flexneri serotyping.

  10. Going in the right direction: mating-type switching of Schizosaccharomyces pombe is controlled by judicious expression of two different swi2 transcripts.

    PubMed

    Yu, Chuanhe; Bonaduce, Michael J; Klar, Amar J S

    2012-03-01

    Schizosaccharomyces pombe, the fission yeast, cells alternate between P- and M-mating type, controlled by the alternate alleles of the mating-type locus (mat1). The mat1 switching occurs by replacing mat1 with a copy derived from a silenced "donor locus," mat2P or mat3M. The mechanism of donor choice ensuring that switching occurs primarily and productively to the opposite type, called directionality, is largely unknown. Here we identified the mat1-Mc gene, a mammalian sex-determination gene (SRY) homolog, as the primary gene that dictates directionality in M cells. A previously unrecognized, shorter swi2 mRNA, a truncated form of the swi2, was identified, and its expression requires the mat1-Mc function. We also found that the abp1 gene (human CENPB homolog) controls directionality through swi2 regulation. In addition, we implicated a cis-acting DNA sequence in mat2 utilization. Overall, we showed that switching directionality is controlled by judicious expression of two swi2 transcripts through a cell-type-regulated dual promoter. In this respect, this regulation mechanism resembles that of the Drosophila sex-determination Slx gene.

  11. Going in the Right Direction: Mating-Type Switching of Schizosaccharomyces pombe Is Controlled by Judicious Expression of Two Different swi2 Transcripts

    PubMed Central

    Yu, Chuanhe; Bonaduce, Michael J.; Klar, Amar J. S.

    2012-01-01

    Schizosaccharomyces pombe, the fission yeast, cells alternate between P- and M-mating type, controlled by the alternate alleles of the mating-type locus (mat1). The mat1 switching occurs by replacing mat1 with a copy derived from a silenced “donor locus,” mat2P or mat3M. The mechanism of donor choice ensuring that switching occurs primarily and productively to the opposite type, called directionality, is largely unknown. Here we identified the mat1-Mc gene, a mammalian sex-determination gene (SRY) homolog, as the primary gene that dictates directionality in M cells. A previously unrecognized, shorter swi2 mRNA, a truncated form of the swi2, was identified, and its expression requires the mat1-Mc function. We also found that the abp1 gene (human CENPB homolog) controls directionality through swi2 regulation. In addition, we implicated a cis-acting DNA sequence in mat2 utilization. Overall, we showed that switching directionality is controlled by judicious expression of two swi2 transcripts through a cell-type-regulated dual promoter. In this respect, this regulation mechanism resembles that of the Drosophila sex-determination Slx gene. PMID:22209903

  12. Diversity of mating-type chromosome structures in the yeast Zygosaccharomyces rouxii caused by ectopic exchanges between MAT-like loci.

    PubMed

    Watanabe, Jun; Uehara, Kenji; Mogi, Yoshinobu

    2013-01-01

    We investigated sex chromosome diversity in Zygosaccharomyces rouxii (Z. rouxii). In the current study, we show that the organization of the mating-type (MAT) locus is highly variable in the Z. rouxii population, indicating the MAT, HML, and HMR loci are translocation hotspots. Although NBRC1130 and CBS732 were originally two stocks of the type strain of the species, only NBRC1130 retains the original karyotype. A reciprocal translocation between the MAT and HMR loci appears to have occurred during the early passage culture of CBS732, which was used for genome sequencing. In NBRC1733, NBRC0686, NBRC0740 and NBRC1053, the terminal region of the chromosome containing the HMR locus was replaced with the chromosomal region to the left of the MAT or HML loci. The translocation events found in NBRC1733, NBRC0686, NBRC0740, and NBRC1053 were reconstructed under our experimental conditions using the DA2 background, and the reconstruction suggests that the frequency of this type of translocation is approximately 10(-7). These results suggest that the MAT and MAT-like loci were the susceptible regions in the genome, and the diversity of mating-type chromosome structures in Z. rouxii was caused by ectopic exchanges between MAT-like loci.

  13. Diversity of Mating-Type Chromosome Structures in the Yeast Zygosaccharomyces rouxii Caused by Ectopic Exchanges between MAT-Like Loci

    PubMed Central

    Watanabe, Jun; Uehara, Kenji; Mogi, Yoshinobu

    2013-01-01

    We investigated sex chromosome diversity in Zygosaccharomyces rouxii (Z. rouxii). In the current study, we show that the organization of the mating-type (MAT) locus is highly variable in the Z. rouxii population, indicating the MAT, HML, and HMR loci are translocation hotspots. Although NBRC1130 and CBS732 were originally two stocks of the type strain of the species, only NBRC1130 retains the original karyotype. A reciprocal translocation between the MAT and HMR loci appears to have occurred during the early passage culture of CBS732, which was used for genome sequencing. In NBRC1733, NBRC0686, NBRC0740 and NBRC1053, the terminal region of the chromosome containing the HMR locus was replaced with the chromosomal region to the left of the MAT or HML loci. The translocation events found in NBRC1733, NBRC0686, NBRC0740, and NBRC1053 were reconstructed under our experimental conditions using the DA2 background, and the reconstruction suggests that the frequency of this type of translocation is approximately 10−7. These results suggest that the MAT and MAT-like loci were the susceptible regions in the genome, and the diversity of mating-type chromosome structures in Z. rouxii was caused by ectopic exchanges between MAT-like loci. PMID:23614024

  14. Genetic Diversity and Mating Type Distribution of Tuber melanosporum and Their Significance to Truffle Cultivation in Artificially Planted Truffiéres in Australia

    PubMed Central

    Selmes, H.

    2012-01-01

    Tuber melanosporum is a truffle native to Europe and is cultivated in countries such as Australia for the gastronomic market, where production yields are often lower than expected. We assessed the genetic diversity of T. melanosporum with six microsatellite loci to assess the effect of genetic drift on truffle yield in Australia. Genetic diversity as assessed on 210 ascocarps revealed a higher allelic diversity compared to previous studies from Europe, suggesting a possible genetic expansion and/or multiple and diverse source populations for inoculum. The results also suggest that the single sequence repeat diversity of locus ME2 is adaptive and that, for example, the probability of replication errors is increased for this locus. Loss of genetic diversity in Australian populations is therefore not a likely factor in limiting ascocarp production. A survey of nursery seedlings and trees inoculated with T. melanosporum revealed that <70% of seedlings and host trees were colonized with T. melanosporum and that some trees had been contaminated by Tuber brumale, presumably during the inoculation process. Mating type (MAT1-1-1 and MAT1-2-1) analyses on seedling and four- to ten-year-old host trees found that 100% of seedlings but only approximately half of host trees had both mating types present. Furthermore, MAT1-1-1 was detected significantly more commonly than MAT1-2-1 in established trees, suggesting a competitive advantage for MAT1-1-1 strains. This study clearly shows that there are more factors involved in ascocarp production than just the presence of both mating types on host trees. PMID:22773652

  15. Tracing the Origin of the Fungal α1 Domain Places Its Ancestor in the HMG-Box Superfamily: Implication for Fungal Mating-Type Evolution

    PubMed Central

    van Tilbeurgh, Herman; Ripoll, Daniel R.; Dixelius, Christina; Turgeon, B. Gillian; Debuchy, Robert

    2010-01-01

    Background Fungal mating types in self-incompatible Pezizomycotina are specified by one of two alternate sequences occupying the same locus on corresponding chromosomes. One sequence is characterized by a gene encoding an HMG protein, while the hallmark of the other is a gene encoding a protein with an α1 domain showing similarity to the Matα1p protein of Saccharomyces cerevisiae. DNA-binding HMG proteins are ubiquitous and well characterized. In contrast, α1 domain proteins have limited distribution and their evolutionary origin is obscure, precluding a complete understanding of mating-type evolution in Ascomycota. Although much work has focused on the role of the S. cerevisiae Matα1p protein as a transcription factor, it has not yet been placed in any of the large families of sequence-specific DNA-binding proteins. Methodology/Principal Findings We present sequence comparisons, phylogenetic analyses, and in silico predictions of secondary and tertiary structures, which support our hypothesis that the α1 domain is related to the HMG domain. We have also characterized a new conserved motif in α1 proteins of Pezizomycotina. This motif is immediately adjacent to and downstream of the α1 domain and consists of a core sequence Y-[LMIF]-x(3)-G-[WL] embedded in a larger conserved motif. Conclusions/Significance Our data suggest that extant α1-box genes originated from an ancestral HMG gene, which confirms the current model of mating-type evolution within the fungal kingdom. We propose to incorporate α1 proteins in a new subclass of HMG proteins termed MATα_HMG. PMID:21170349

  16. Mating-type switching by chromosomal inversion in methylotrophic yeasts suggests an origin for the three-locus Saccharomyces cerevisiae system.

    PubMed

    Hanson, Sara J; Byrne, Kevin P; Wolfe, Kenneth H

    2014-11-11

    Saccharomyces cerevisiae has a complex system for switching the mating type of haploid cells, requiring the genome to have three mating-type (MAT)-like loci and a mechanism for silencing two of them. How this system originated is unknown, because the three-locus system is present throughout the family Saccharomycetaceae, whereas species in the sister Candida clade have only one locus and do not switch. Here we show that yeasts in a third clade, the methylotrophs, have a simpler two-locus switching system based on reversible inversion of a section of chromosome with MATa genes at one end and MATalpha genes at the other end. In Hansenula polymorpha the 19-kb invertible region lies beside a centromere so that, depending on the orientation, either MATa or MATalpha is silenced by centromeric chromatin. In Pichia pastoris, the orientation of a 138-kb invertible region puts either MATa or MATalpha beside a telomere and represses transcription of MATa2 or MATalpha2. Both species are homothallic, and inversion of their MAT regions can be induced by crossing two strains of the same mating type. The three-locus system of S. cerevisiae, which uses a nonconservative mechanism to replace DNA at MAT, likely evolved from a conservative two-locus system that swapped genes between expression and nonexpression sites by inversion. The increasing complexity of the switching apparatus, with three loci, donor bias, and cell lineage tracking, can be explained by continuous selection to increase sporulation ability in young colonies. Our results provide an evolutionary context for the diversity of switching and silencing mechanisms.

  17. Genetic diversity and mating type distribution of Tuber melanosporum and their significance to truffle cultivation in artificially planted truffieres in Australia.

    PubMed

    Linde, C C; Selmes, H

    2012-09-01

    Tuber melanosporum is a truffle native to Europe and is cultivated in countries such as Australia for the gastronomic market, where production yields are often lower than expected. We assessed the genetic diversity of T. melanosporum with six microsatellite loci to assess the effect of genetic drift on truffle yield in Australia. Genetic diversity as assessed on 210 ascocarps revealed a higher allelic diversity compared to previous studies from Europe, suggesting a possible genetic expansion and/or multiple and diverse source populations for inoculum. The results also suggest that the single sequence repeat diversity of locus ME2 is adaptive and that, for example, the probability of replication errors is increased for this locus. Loss of genetic diversity in Australian populations is therefore not a likely factor in limiting ascocarp production. A survey of nursery seedlings and trees inoculated with T. melanosporum revealed that <70% of seedlings and host trees were colonized with T. melanosporum and that some trees had been contaminated by Tuber brumale, presumably during the inoculation process. Mating type (MAT1-1-1 and MAT1-2-1) analyses on seedling and four- to ten-year-old host trees found that 100% of seedlings but only approximately half of host trees had both mating types present. Furthermore, MAT1-1-1 was detected significantly more commonly than MAT1-2-1 in established trees, suggesting a competitive advantage for MAT1-1-1 strains. This study clearly shows that there are more factors involved in ascocarp production than just the presence of both mating types on host trees.

  18. The Fission Yeast Ubiquitin-Conjugating Enzymes UbcP3, Ubc15, and Rhp6 Affect Transcriptional Silencing of the Mating-Type Region

    PubMed Central

    Sig Nielsen, Inga; Nielsen, Olaf; Murray, Johanne M.; Thon, Geneviève

    2002-01-01

    Genes transcribed by RNA polymerase II are silenced when introduced near the mat2 or mat3 mating-type loci of the fission yeast Schizosaccharomyces pombe. Silencing is mediated by a number of gene products and cis-acting elements. We report here the finding of novel trans-acting factors identified in a screen for high-copy-number disruptors of silencing. Expression of cDNAs encoding the putative E2 ubiquitin-conjugating enzymes UbcP3, Ubc15 (ubiquitin-conjugating enzyme), or Rhp6 (Rad homolog pombe) from the strong nmt1 promoter derepressed the silent mating-type loci mat2 and mat3 and reporter genes inserted nearby. Deletion of rhp6 slightly derepressed an ade6 reporter gene placed in the mating-type region, whereas disruption of ubcP3 or ubc15 had no obvious effect on silencing. Rhp18 is the S. pombe homolog of Saccharomyces cerevisiae Rad18p, a DNA-binding protein that physically interacts with Rad6p. Rhp18 was not required for the derepression observed when UbcP3, Ubc15, or Rhp6 was overproduced. Overexpressing Rhp6 active-site mutants showed that the ubiquitin-conjugating activity of Rhp6 is essential for disruption of silencing. However, high dosage of UbcP3, Ubc15, or Rhp6 was not suppressed by a mutation in the 26S proteasome, suggesting that loss of silencing is not due to an increased degradation of silencing factors but rather to the posttranslational modification of proteins by ubiquitination. We discuss the implications of these results for the possible modes of action of UbcP3, Ubc15, and Rhp6. PMID:12456009

  19. The fission yeast ubiquitin-conjugating enzymes UbcP3, Ubc15, and Rhp6 affect transcriptional silencing of the mating-type region.

    PubMed

    Nielsen, Inga Sig; Nielsen, Olaf; Murray, Johanne M; Thon, Geneviève

    2002-08-01

    Genes transcribed by RNA polymerase II are silenced when introduced near the mat2 or mat3 mating-type loci of the fission yeast Schizosaccharomyces pombe. Silencing is mediated by a number of gene products and cis-acting elements. We report here the finding of novel trans-acting factors identified in a screen for high-copy-number disruptors of silencing. Expression of cDNAs encoding the putative E2 ubiquitin-conjugating enzymes UbcP3, Ubc15 (ubiquitin-conjugating enzyme), or Rhp6 (Rad homolog pombe) from the strong nmt1 promoter derepressed the silent mating-type loci mat2 and mat3 and reporter genes inserted nearby. Deletion of rhp6 slightly derepressed an ade6 reporter gene placed in the mating-type region, whereas disruption of ubcP3 or ubc15 had no obvious effect on silencing. Rhp18 is the S. pombe homolog of Saccharomyces cerevisiae Rad18p, a DNA-binding protein that physically interacts with Rad6p. Rhp18 was not required for the derepression observed when UbcP3, Ubc15, or Rhp6 was overproduced. Overexpressing Rhp6 active-site mutants showed that the ubiquitin-conjugating activity of Rhp6 is essential for disruption of silencing. However, high dosage of UbcP3, Ubc15, or Rhp6 was not suppressed by a mutation in the 26S proteasome, suggesting that loss of silencing is not due to an increased degradation of silencing factors but rather to the posttranslational modification of proteins by ubiquitination. We discuss the implications of these results for the possible modes of action of UbcP3, Ubc15, and Rhp6.

  20. Mating-type switching by chromosomal inversion in methylotrophic yeasts suggests an origin for the three-locus Saccharomyces cerevisiae system

    PubMed Central

    Hanson, Sara J.; Byrne, Kevin P.; Wolfe, Kenneth H.

    2014-01-01

    Saccharomyces cerevisiae has a complex system for switching the mating type of haploid cells, requiring the genome to have three mating-type (MAT)–like loci and a mechanism for silencing two of them. How this system originated is unknown, because the three-locus system is present throughout the family Saccharomycetaceae, whereas species in the sister Candida clade have only one locus and do not switch. Here we show that yeasts in a third clade, the methylotrophs, have a simpler two-locus switching system based on reversible inversion of a section of chromosome with MATa genes at one end and MATalpha genes at the other end. In Hansenula polymorpha the 19-kb invertible region lies beside a centromere so that, depending on the orientation, either MATa or MATalpha is silenced by centromeric chromatin. In Pichia pastoris, the orientation of a 138-kb invertible region puts either MATa or MATalpha beside a telomere and represses transcription of MATa2 or MATalpha2. Both species are homothallic, and inversion of their MAT regions can be induced by crossing two strains of the same mating type. The three-locus system of S. cerevisiae, which uses a nonconservative mechanism to replace DNA at MAT, likely evolved from a conservative two-locus system that swapped genes between expression and nonexpression sites by inversion. The increasing complexity of the switching apparatus, with three loci, donor bias, and cell lineage tracking, can be explained by continuous selection to increase sporulation ability in young colonies. Our results provide an evolutionary context for the diversity of switching and silencing mechanisms. PMID:25349420

  1. Binding of the Fkh1 Forkhead Associated Domain to a Phosphopeptide within the Mph1 DNA Helicase Regulates Mating-Type Switching in Budding Yeast

    PubMed Central

    Su, Zhangli; Cherney, Rachel; Choi, Koyi; Denu, John; Zhao, Xiaolan; Fox, Catherine A.

    2016-01-01

    The Saccharomyces cerevisiae Fkh1 protein has roles in cell-cycle regulated transcription as well as a transcription-independent role in recombination donor preference during mating-type switching. The conserved FHA domain of Fkh1 regulates donor preference by juxtaposing two distant regions on chromosome III to promote their recombination. A model posits that this Fkh1-mediated long-range chromosomal juxtaposition requires an interaction between the FHA domain and a partner protein(s), but to date no relevant partner has been described. In this study, we used structural modeling, 2-hybrid assays, and mutational analyses to show that the predicted phosphothreonine-binding FHA domain of Fkh1 interacted with multiple partner proteins. The Fkh1 FHA domain was important for its role in cell-cycle regulation, but no single interaction partner could account for this role. In contrast, Fkh1’s interaction with the Mph1 DNA repair helicase regulated donor preference during mating-type switching. Using 2-hybrid assays, co-immunoprecipitation, and fluorescence anisotropy, we mapped a discrete peptide within the regulatory Mph1 C-terminus required for this interaction and identified two threonines that were particularly important. In vitro binding experiments indicated that at least one of these threonines had to be phosphorylated for efficient Fkh1 binding. Substitution of these two threonines with alanines (mph1-2TA) specifically abolished the Fkh1-Mph1 interaction in vivo and altered donor preference during mating-type switching to the same degree as mph1Δ. Notably, the mph1-2TA allele maintained other functions of Mph1 in genome stability. Deletion of a second Fkh1-interacting protein encoded by YMR144W also resulted in a change in Fkh1-FHA-dependent donor preference. We have named this gene FDO1 for Forkhead one interacting protein involved in donor preference. We conclude that a phosphothreonine-mediated protein-protein interface between Fkh1-FHA and Mph1 contributes

  2. Mating competitiveness and life-table comparisons between transgenic and Indian wild-type Aedes aegypti L.

    PubMed Central

    Patil, Prabhakargouda B; Niranjan Reddy, BP; Gorman, Kevin; Seshu Reddy, KV; Barwale, Shirish R; Zehr, Usha B; Nimmo, Derric; Naish, Neil; Alphey, Luke

    2015-01-01

    BACKGROUND OX513A is a genetically engineered strain of Aedes aegypti carrying a repressible, dominantly inherited transgene that confers lethality in immature heterozygous progeny. Released male OX513A adults have proven to be effective for the localised suppression of wild Ae. aegypti, highlighting its potential in vector control. Mating and life-table assessments were used to compare OX513A with reared Ae. aegypti strains collected from New Delhi and Aurangabad regions in India. RESULTS Mating proportions of New Delhi females versus males of OX513A or New Delhi strains were 0.52 and 0.48 respectively, indicating no discrimination by females against either strain, and males of both strains were equally competitive. Developmental time from first instar to adult emergence was significantly longer for OX513A (10.7 ± 0.04 days) than for New Delhi (9.4 ± 0.04 days) and Aurangabad strains (9.1 ± 0.04 days). Differences in mean longevities, female reproductive parameters and population growth parameters between the strains were non-significant. CONCLUSIONS The laboratory study demonstrates that only minor life-table variations of limited biological relevance exist between OX513A and Indian Ae. aegypti populations, and males had equal potential for mating competitiveness. Thus, results support the OX513A strain as a suitable candidate for continued evaluation towards sustainable management of Ae. aegypti populations in India. © 2014 Gangabishan Bhikulal Investment and Trading Limited. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25078081

  3. A recombinationally repressed region between mat2 and mat3 loci shares homology to centromeric repeats and regulates directionality of mating-type switching in fission yeast.

    PubMed

    Grewal, S I; Klar, A J

    1997-08-01

    Cells of the fission yeast Schizosaccharomyces pombe switch mating type by replacing genetic information at the transcriptionally active mat1 locus with sequences copied from one of two closely linked silent loci, mat2-P or mat3-M. By a process referred to as directionality of switching, cells predominantly switch to the opposite mat1 allele; the mat1-P allele preferentially recombines with mat3, while mat1-M selects the mat2. In contrast to efficient recombination at mat1, recombination within the adjoining mat2-mat3 interval is undetectable. We defined the role of sequences between mat2 and mat3, designated the K-region, in directionality as well as recombinational suppression. Cloning and sequencing analysis revealed that a part of the K-region is homologous to repeat sequences present at centromeres, which also display transcriptional and recombinational suppression. Replacement of 7.5 kb of the K-region with the ura4+ gene affected directionality in a variegated manner. Analysis of the swi6-mod locus, which was previously shown to affect directionality, in K delta::ura4+ strains suggested the existence of at least two overlapping directionality mechanisms. Our work furthers the model that directionality is regulated by cell-type-specific organization of the heterochromatin-like structure in the mating-type region and provides evidence that the K-region contributes to silencing of the mat2-mat3 interval.

  4. A Recombinationally Repressed Region between Mat2 and Mat3 Loci Shares Homology to Centromeric Repeats and Regulates Directionality of Mating-Type Switching in Fission Yeast

    PubMed Central

    Grewal, SIS.; Klar, AJS.

    1997-01-01

    Cells of the fission yeast Schizosaccharomyces pombe switch mating type by replacing genetic information at the transcriptionally active mat1 locus with sequences copied from one of two closely linked silent loci, mat2-P or mat3-M. By a process referred to as directionality of switching, cells predominantly switch to the opposite mat1 allele; the mat1-P allele preferentially recombines with mat3, while mat1-M selects the mat2. In contrast to efficient recombination at mat1, recombination within the adjoining mat2-mat3 interval is undetectable. We defined the role of sequences between mat2 and mat3, designated the K-region, in directionality as well as recombinational suppression. Cloning and sequencing analysis revealed that a part of the K-region is homologous to repeat sequences present at centromeres, which also display transcriptional and recombinational suppression. Replacement of 7.5 kb of the K-region with the ura4(+) gene affected directionality in a variegated manner. Analysis of the swi6-mod locus, which was previously shown to affect directionality, in KΔ::ura4(+) strains suggested the existence of at least two overlapping directionality mechanisms. Our work furthers the model that directionality is regulated by cell-type-specific organization of the heterochromatin-like structure in the mating-type region and provides evidence that the K-region contributes to silencing of the mat2-mat3 interval. PMID:9258669

  5. Identification of Mating Type Genes in the Bipolar Basidiomycetous Yeast Rhodosporidium toruloides: First Insight into the MAT Locus Structure of the Sporidiobolales▿ †

    PubMed Central

    Coelho, Marco A.; Rosa, André; Rodrigues, Nádia; Fonseca, Álvaro; Gonçalves, Paula

    2008-01-01

    Rhodosporidium toruloides is a heterothallic, bipolar, red yeast that belongs to the Sporidiobolales, an order within a major lineage of basidiomycetes, the Pucciniomycotina. In contrast to other basidiomycetes, considerably less is known about the nature of the mating type (MAT) loci that control sexual reproduction in this lineage. Three genes (RHA1, RHA2, and RHA3) encoding precursors of the MAT A1 pheromone (rhodotorucine A) were previously identified and formed the basis for a genome walking approach that led to the identification of additional MAT genes in complementary mating strains of R. toruloides. Two mating type-specific alleles encoding a p21-activated kinase (PAK; Ste20 homolog) were found between the RHA2 and RHA3 genes, and identification in MAT A2 strains of a gene encoding a presumptive pheromone precursor enabled prediction of the structure of rhodotorucine a. In addition, a putative pheromone receptor gene (STE3 homolog) was identified upstream of RHA1. Analyses of genomic data from two closely related species, Sporobolomyces roseus and Sporidiobolus salmonicolor, identified syntenic regions that contain homologs of all the above-mentioned genes. Notably, six novel pheromone precursor genes were uncovered, which encoded, similarly to the RHA genes, multiple tandem copies of the peptide moiety. This suggests that this structure, which is unique among fungal lipopeptide pheromones, seems to be prevalent in red yeasts. Species comparisons provided evidence for a large, multigenic MAT locus structure in the Sporidiobolales, but no putative homeodomain transcription factor genes (which are present in all basidiomycetous MAT loci characterized thus far) could be found in any of the three species in the vicinity of the MAT genes identified. PMID:18408057

  6. How Well Do Molecular and Pedigree Relatedness Correspond, in Populations with Diverse Mating Systems, and Various Types and Quantities of Molecular and Demographic Data?

    PubMed

    Kopps, Anna M; Kang, Jungkoo; Sherwin, William B; Palsbøll, Per J

    2015-06-30

    Kinship analyses are important pillars of ecological and conservation genetic studies with potentially far-reaching implications. There is a need for power analyses that address a range of possible relationships. Nevertheless, such analyses are rarely applied, and studies that use genetic-data-based-kinship inference often ignore the influence of intrinsic population characteristics. We investigated 11 questions regarding the correct classification rate of dyads to relatedness categories (relatedness category assignments; RCA) using an individual-based model with realistic life history parameters. We investigated the effects of the number of genetic markers; marker type (microsatellite, single nucleotide polymorphism SNP, or both); minor allele frequency; typing error; mating system; and the number of overlapping generations under different demographic conditions. We found that (i) an increasing number of genetic markers increased the correct classification rate of the RCA so that up to >80% first cousins can be correctly assigned; (ii) the minimum number of genetic markers required for assignments with 80 and 95% correct classifications differed between relatedness categories, mating systems, and the number of overlapping generations; (iii) the correct classification rate was improved by adding additional relatedness categories and age and mitochondrial DNA data; and (iv) a combination of microsatellite and single-nucleotide polymorphism data increased the correct classification rate if <800 SNP loci were available. This study shows how intrinsic population characteristics, such as mating system and the number of overlapping generations, life history traits, and genetic marker characteristics, can influence the correct classification rate of an RCA study. Therefore, species-specific power analyses are essential for empirical studies.

  7. How Well Do Molecular and Pedigree Relatedness Correspond, in Populations with Diverse Mating Systems, and Various Types and Quantities of Molecular and Demographic Data?

    PubMed Central

    Kopps, Anna M.; Kang, Jungkoo; Sherwin, William B.; Palsbøll, Per J.

    2015-01-01

    Kinship analyses are important pillars of ecological and conservation genetic studies with potentially far-reaching implications. There is a need for power analyses that address a range of possible relationships. Nevertheless, such analyses are rarely applied, and studies that use genetic-data-based-kinship inference often ignore the influence of intrinsic population characteristics. We investigated 11 questions regarding the correct classification rate of dyads to relatedness categories (relatedness category assignments; RCA) using an individual-based model with realistic life history parameters. We investigated the effects of the number of genetic markers; marker type (microsatellite, single nucleotide polymorphism SNP, or both); minor allele frequency; typing error; mating system; and the number of overlapping generations under different demographic conditions. We found that (i) an increasing number of genetic markers increased the correct classification rate of the RCA so that up to >80% first cousins can be correctly assigned; (ii) the minimum number of genetic markers required for assignments with 80 and 95% correct classifications differed between relatedness categories, mating systems, and the number of overlapping generations; (iii) the correct classification rate was improved by adding additional relatedness categories and age and mitochondrial DNA data; and (iv) a combination of microsatellite and single-nucleotide polymorphism data increased the correct classification rate if <800 SNP loci were available. This study shows how intrinsic population characteristics, such as mating system and the number of overlapping generations, life history traits, and genetic marker characteristics, can influence the correct classification rate of an RCA study. Therefore, species-specific power analyses are essential for empirical studies. PMID:26134496

  8. The Type VI Secretion System Encoded in Salmonella Pathogenicity Island 19 Is Required for Salmonella enterica Serotype Gallinarum Survival within Infected Macrophages

    PubMed Central

    Blondel, Carlos J.; Jiménez, Juan C.; Leiva, Lorenzo E.; Álvarez, Sergio A.; Pinto, Bernardo I.; Contreras, Francisca; Pezoa, David; Santiviago, Carlos A.

    2013-01-01

    Salmonella enterica serotype Gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. We have reported that S. Gallinarum harbors a type VI secretion system (T6SS) encoded in Salmonella pathogenicity island 19 (SPI-19) that is required for efficient colonization of chicks. In the present study, we aimed to characterize the SPI-19 T6SS functionality and to investigate the mechanisms behind the phenotypes previously observed in vivo. Expression analyses revealed that SPI-19 T6SS core components are expressed and produced under in vitro bacterial growth conditions. However, secretion of the structural/secreted components Hcp1, Hcp2, and VgrG to the culture medium could not be determined, suggesting that additional signals are required for T6SS-dependent secretion of these proteins. In vitro bacterial competition assays failed to demonstrate a role for SPI-19 T6SS in interbacterial killing. In contrast, cell culture experiments with murine and avian macrophages (RAW264.7 and HD11, respectively) revealed production of a green fluorescent protein-tagged version of VgrG soon after Salmonella uptake. Furthermore, infection of RAW264.7 and HD11 macrophages with deletion mutants of SPI-19 or strains with genes encoding specific T6SS core components (clpV and vgrG) revealed that SPI-19 T6SS contributes to S. Gallinarum survival within macrophages at 20 h postuptake. SPI-19 T6SS function was not linked to Salmonella-induced cytotoxicity or cell death of infected macrophages, as has been described for other T6SS. Our data indicate that SPI-19 T6SS corresponds to a novel tool used by Salmonella to survive within host cells. PMID:23357385

  9. hsdS, Belonging to the Type I Restriction-Modification System, Contributes to the Streptococcus suis Serotype 2 Survival Ability in Phagocytes

    PubMed Central

    Xu, Bin; Zhang, Ping; Li, Weiyi; Liu, Rui; Tang, Jinsheng; Fan, Hongjie

    2017-01-01

    Streptococcus suis serotype 2 (SS2) is an important zoonotic agent in swine and humans. Anti-phagocytosis and survival in phagocytic cells and whole blood is essential for bacteria to be pathogenic. In this study, the host specificity determinant specificity subunit (coded by hsdS) of the Type I Restriction-Modification system and two peptidoglycan-binding proteins (coded by lysM and lysM′, respectively), which were simultaneously found to be subjected to transcript-level influence by hsdS, were identified to facilitate the anti-phagocytosis of SS2 to a microglia cell line BV2. Furthermore, they significantly enhanced its survival in BV2, whole blood, and a peroxidation environment (H2O2) (p < 0.05), yet not in the acidic condition based on statistical analysis of the characteristic differences between gene mutants and wild-type SS2. In contrast, another specificity subunit, coded by hsdS′, that belonged to the same Type I Restriction-Modification system, only significantly reduced the survival ability of SS2 in the acidic condition when in the form of a gene-deleted mutant (p < 0.05), but it did not significantly influence the survival ability in other conditions mentioned above or have enhanced anti-phagocytosis action when compared with wild-type SS2. In addition, the mutation of hsdS significantly enhanced the secretion of nitric oxide and TNF-α by BV2 with SS2 incubation (p < 0.05). The SS2 was tested, and it failed to stimulate BV2 to produce IFN-γ. These results demonstrated that hsdS contributed to bacterial anti-phagocytosis and survival in adverse host environments through positively impacting the transcription of two peptidoglycan-binding protein genes, enhancing resistance to reactive oxygen species, and reducing the secretion of TNF-α and nitric oxide by phagocytes. These findings revealed new mechanisms of SS2 pathogenesis. PMID:28848531

  10. Monoclonal antibodies to serotype 2 and serotype 15 outer membrane proteins of Neisseria meningitidis and their use in serotyping.

    PubMed Central

    Zollinger, W D; Moran, E E; Connelly, H; Mandrell, R E; Brandt, B

    1984-01-01

    A series of murine monoclonal antibodies to serotype 2 and serotype 15 strains of Neisseria meningitidis were produced which were specific for outer membrane proteins of classes 1, 2, 3, and 5. A panel of eight monoclonal antibodies that exhibited a high degree of serotype specificity when reacted with prototype strains of known serotype were selected for study. Each of the corresponding epitopes was localized on a specific outer membrane protein by means of immunoprecipitation, electroblotting, or both. The serotype 2a-, 2b-, and 2c-specific antibodies bound to the class 2 protein, the serotype 15-specific antibody bound to the class 3 protein, two antibodies (3-1-P1.2 and 3-1-P1.16) bound to class 1 proteins, and two antibodies (1-1-P5.1 and 3-1-P5.2) bound to class 5 proteins. Six of these monoclonal antibodies were used in a spot-blot procedure to survey 122 case isolates (groups B, C, Y, and W135) and 363 carrier isolates (all serogroups) for the presence of the 2a, 2b, 2c, 15, P1.2, and P1.16 epitopes. A total of 66% of the case isolates and 30% of the carrier isolates reacted with one or more of the monoclonal antibodies. The use of monoclonal antibodies for serotyping of meningococci appears to be feasible and easy and appears to have significant advantages over the use of polyclonal typing sera. Images PMID:6434428

  11. Distribution of mating-type alleles and M13 PCR markers in the black leaf spot fungus Mycosphaerella fijiensis of bananas in Brazil.

    PubMed

    Queiroz, C B; Miranda, E C; Hanada, R E; Sousa, N R; Gasparotto, L; Soares, M A; Silva, G F

    2013-02-08

    The fungus Mycosphaerella fijiensis is the causative agent of black sigatoka, which is one of the most destructive diseases of banana plants. Infection with this pathogen results in underdeveloped fruit, with no commercial value. We analyzed the distribution of the M. fijiensis mating-type system and its genetic variability using M13 phage DNA markers. We found a 1:1 distribution of mating-type alleles, indicating MAT1-1 and MAT1-2 idiomorphs. A polymorphism analysis using three different primers for M13 markers showed that only the M13 minisatellite primers generated polymorphic products. We then utilized this polymorphism to characterize 40 isolates from various Brazilian states. The largest genetic distances were found between isolates from the same location and between isolates from different parts of the country. Therefore, there was no correlation between the genetic similarity and the geographic origin of the isolates. The M13 marker was used to generate genetic fingerprints for five isolates; these fingerprints were compared with the band profiles obtained from inter-simple sequence repeat (UBC861) and inter-retrotransposon amplified polymorphism analyses. We found that the M13 marker was more effective than the other two markers for differentiating these isolates.

  12. A MADS Box Protein Interacts with a Mating-Type Protein and Is Required for Fruiting Body Development in the Homothallic Ascomycete Sordaria macrospora

    PubMed Central

    Nolting, Nicole; Pöggeler, Stefanie

    2006-01-01

    MADS box transcription factors control diverse developmental processes in plants, metazoans, and fungi. To analyze the involvement of MADS box proteins in fruiting body development of filamentous ascomycetes, we isolated the mcm1 gene from the homothallic ascomycete Sordaria macrospora, which encodes a putative homologue of the Saccharomyces cerevisiae MADS box protein Mcm1p. Deletion of the S. macrospora mcm1 gene resulted in reduced biomass, increased hyphal branching, and reduced hyphal compartment length during vegetative growth. Furthermore, the S. macrospora Δmcm1 strain was unable to produce fruiting bodies or ascospores during sexual development. A yeast two-hybrid analysis in conjugation with in vitro analyses demonstrated that the S. macrospora MCM1 protein can interact with the putative transcription factor SMTA-1, encoded by the S. macrospora mating-type locus. These results suggest that the S. macrospora MCM1 protein is involved in the transcriptional regulation of mating-type-specific genes as well as in fruiting body development. PMID:16835449

  13. Quantitative analysis of serum neutralization of human immunodeficiency virus type 1 from subtypes A, B, C, D, E, F, and I: lack of direct correlation between neutralization serotypes and genetic subtypes and evidence for prevalent serum-dependent infectivity enhancement.

    PubMed Central

    Kostrikis, L G; Cao, Y; Ngai, H; Moore, J P; Ho, D D

    1996-01-01

    Human immunodeficiency virus type 1 (HIV-1) M group strains have been assigned to date to nine distinct genetic subtypes, designated A through I, according to phylogenetic analyses of nucleotide sequences of their env or gag genes. Whether there is any relationship between phylogenetic subtypes and the neutralization serotypes is not clear, yet defining the nature of any such relationship by mathematical means would be of major importance for the development of globally effective HIV-1 vaccines. We have therefore developed a quantitative method to analyze serum neutralization of HIV-1 isolates and to identify HIV-1 neutralization serotypes. This method involves calculations of the neutralization index, N(i), a newly defined parameter derived from plots generated from in vitro neutralization assays, calculations of pairwise serum-virus vector distances, and cluster analyses. We have applied this approach to analyze three independent neutralization matrices involving primary HIV-1 strains and sera from genetic subtypes A, B, C, D, E, F, and I. Detailed serum and HIV-1 isolate cluster analyses have shown that in general, the identified neutralization serotypes do not directly correlate with HIV-1 genetic subtypes. These results suggest that neutralization serotypes do not during natural HIV-1 infection are not governed by antibodies directed against simple epitopes within gp120 monomers. A significant proportion (28%) of 1,213 combinations of sera and HIV-1 isolates caused serum-dependent infectivity enhancement [negative N(i) values] rather than neutralization. We also noted that negative N(i) values tended to correlate better with certain HIV-1 isolates rather than with HIV-1-positive sera. Syncytium-inducing variants of HIV-1 were slightly more likely than non-syncytium-inducing variants to undergo serum-dependent infectivity enhancement, although the latter variants could clearly be susceptible to enhancement. PMID:8523557

  14. Prevalence and Genetic Structures of Streptococcus pneumoniae Serotype 6D, South Korea

    PubMed Central

    Choi, Eun Hwa; Cho, Eun Young; Oh, Chi Eun; Eun, Byung Wook; Lee, Jina; Kim, Min Ja

    2010-01-01

    To determine prevalence and genetic structures of new serotype 6D strains of pneumococci, we examined isolates from diverse clinical specimens in South Korea during 1991–2008. Fourteen serotype 6D strains accounted for 10.4% of serogroup 6 pneumococci from blood, sputum, nasopharynx, and throat samples. Serotype 6D strains consisted of 3 sequence types. PMID:21029535

  15. Rapid, selective digestion of mitochondrial DNA in accordance with the matA hierarchy of multiallelic mating types in the mitochondrial inheritance of Physarum polycephalum.

    PubMed

    Moriyama, Y; Kawano, S

    2003-07-01

    Although mitochondria are inherited uniparentally in nearly all eukaryotes, the mechanism for this is unclear. When zygotes of the isogamous protist Physarum polycephalum were stained with DAPI, the fluorescence of mtDNA in half of the mitochondria decreased simultaneously to give small spots and then disappeared completely approximately 1.5 hr after nuclear fusion, while the other mitochondrial nucleoids and all of the mitochondrial sheaths remained unchanged. PCR analysis of single zygote cells confirmed that the loss was limited to mtDNA from one parent. The vacant mitochondrial sheaths were gradually eliminated by 60 hr after mating. Using six mating types, the transmission patterns of mtDNA were examined in all possible crosses. In 39 of 60 crosses, strict uniparental inheritance was confirmed in accordance with a hierarchy of relative sexuality. In the other crosses, however, mtDNA from both parents was transmitted to plasmodia. The ratio of parental mtDNA was estimated to be from 1:1 to 1:10(-4). Nevertheless, the matA hierarchy was followed. In these crosses, the mtDNA was incompletely digested, and mtDNA replicated during subsequent plasmodial development. We conclude that the rapid, selective digestion of mtDNA promotes the uniparental inheritance of mitochondria; when this fails, biparental inheritance occurs.

  16. Age-Specific Cluster of Cases of Serotype 1 Streptococcus pneumoniae Carriage in Remote Indigenous Communities in Australia ▿

    PubMed Central

    Smith-Vaughan, H.; Marsh, R.; Mackenzie, G.; Fisher, J.; Morris, P. S.; Hare, K.; McCallum, G.; Binks, M.; Murphy, D.; Lum, G.; Cook, H.; Krause, V.; Jacups, S.; Leach, A. J.

    2009-01-01

    Seven-valent pneumococcal conjugate vaccination commenced in 2001 for Australian indigenous infants. Pneumococcal carriage surveillance detected substantial replacement with nonvaccine serotypes and a cluster of serotype 1 carriage. Our aim was to review Streptococcus pneumoniae serotype 1 carriage and invasive pneumococcal disease (IPD) data for this population and to analyze serotype 1 isolates. Carriage data were collected between 1992 and 2004 in the Darwin region, one of the five regions in the Northern Territory. Carriage data were also collected in 2003 and 2005 from four regions in the Northern Territory. Twenty-six cases of serotype 1 IPD were reported from 1994 to 2007 in the Northern Territory. Forty-four isolates were analyzed by BOX typing and 11 by multilocus sequence typing. In the Darwin region, 26 children were reported carrying serotype 1 (ST227) in 2002 but not during later surveillance. Scattered cases of serotype 1 carriage were noted in two other regions. Cocolonization of serotype 1 with other pneumococcal serotypes was common (34% serotype 1-positive swabs). In conclusion, pneumococcal carriage studies detected intermittent serotype 1 carriage and an ST227 cluster in children in indigenous communities in the Northern Territory of Australia. There was no apparent increase in serotype 1 IPD during this time. The rate of serotype 1 cocolonization with other pneumococcal serotypes suggests that carriage of this serotype may be underestimated. PMID:19091995

  17. Evaluation of serotypes of Staphylococcus aureus strains used in the production of a bovine mastitis bacterin.

    PubMed

    Ma, J; Cocchiaro, J; Lee, J C

    2004-01-01

    The five Staphylococcus aureus strains used in the manufacture of a commercially available bacterin were examined for capsular and surface polysaccharide serotypes. Double immunodiffusion assays of antigenic extracts of test and reference strains with monospecific typing sera to capsular serotypes 1, 2, 5, and 8 and to surface polysaccharide serotype 336 were performed to detect the specific reactivities and antigenic relationships of test samples. Antigenic extracts of two S. aureus strains reacted with antibodies to serotype 8, but not with antibodies to serotype 5, by producing specific precipitin lines. A third strain reacted with monospecific antibodies to serotype 5 and not with the antibodies to serotype 8. The extracts of two other strains failed to exhibit any detectable reaction with antiserum to serotypes 1, 2, 5, or 8. Antibodies to serotype 336, however, precipitated an identical, specific 336 antigen from the antigenic extracts of these two nontypeable strains. Thus, S. aureus bacterin includes one serotype 5, two serotype 8, and two serotype 336 strains, the three predominant serotypes responsible for bovine mastitis.

  18. Mating type and ploidy effect on the β-glucosidase activity and ethanol-producing performance of Saccharomyces cerevisiae with multiple δ-integrated bgl1 gene.

    PubMed

    Wang, Jianjun; Ma, Yuanyuan; Zhang, Kun; Yang, Huajun; Liu, Cheng; Zou, Shaolan; Hong, Jiefang; Zhang, Minhua

    2016-08-10

    In order to investigate the effect of mating type and ploidy on enzymatic activity and fermentation performance in yeast with multiple δ-integrated foreign genes, eight ploidy series strains were constructed. The initial haploid strain BGL-a was shown to contain about 19 copies of the bgl1 gene. In rich media containing 2% (w/v) sugar the specific activities of BGL-aα were lower than those of BGL-aa or BGL-αα, which indicates the existence of mating type effects. While the maximum OD660 decreased with rising ploidy, the biomass yield showed no significant difference between the eight strains and the specific activities (expressed as U/mL or U/mg DCW) showed little to no variation. When cellobiose was used as the carbon source and β-glucosidase substrate, β-glucosidase was expressed more quickly and at higher levels than in glucose-containing media. The maximum specific activitiy values obtained were 19.07U/mL and 19.39U/mL for BGL-αα and BGL-aa, repsectively. The anaerobic biomass and ethanol-producing performance in rich media containing 10% cellobiose showed no significant difference among the eight strains. Their maximal ethanol concentrations and corresponding yields ranged from 40.27 to 43.46g/L and 77.56 to 83.71%, respectively. When the acid- and alkali-pretreated corncob (10% solids content) was used, the diploid BGL-aα fermented the best. When urea was used as the only supplemented nutrient, the ethanol titer and yield were 35.65g/L and 83.69%, respectively, while a control experiment using industrial Angel yeast with exogenous β-glucosidase addition gave values of 37.93g/L and 89.04%. The combined effects of δ-integration of bgl1, ploidy and mating type result in BGL-aa or BGL-αα being the optimal choice for enzyme production and BGL-aα being more suitable for cellulosic ethanol fermentation. These results provide valuable information for future yeast breeding and utilization efforts.

  19. DNA Sequence-Based Subtyping and Evolutionary Analysis of Selected Salmonella enterica Serotypes

    PubMed Central

    Sukhnanand, Sharinne; Alcaine, Sam; Warnick, Lorin D.; Su, Wan-Lin; Hof, Jessica; Craver, Mary Pat J.; McDonough, Patrick; Boor, Kathryn J.; Wiedmann, Martin

    2005-01-01

    While serotyping and phage typing have been used widely to characterize Salmonella isolates, sensitive subtyping methods that allow for evolutionary analyses are essential for examining Salmonella transmission, ecology, and evolution. A set of 25 Salmonella enterica isolates, representing five clinically relevant serotypes (serotypes Agona, Heidelberg, Schwarzengrund, Typhimurium, and Typhimurium var. Copenhagen) was initially used to develop a multilocus sequence typing (MLST) scheme for Salmonella targeting seven housekeeping and virulence genes (panB, fimA, aceK, mdh, icdA, manB, and spaN). A total of eight MLST types were found among the 25 isolates sequenced. A good correlation between MLST types and Salmonella serotypes was observed; only one serotype Typhimurium var. Copenhagen isolate displayed an MLST type otherwise typical for serotype Typhimurium isolates. Since manB, fimA, and mdh allowed for the highest subtype discrimination among the initial 25 isolates, we chose these three genes to perform DNA sequencing of an additional 41 Salmonella isolates representing a larger diversity of serotypes. This “three-gene sequence typing scheme” allowed discrimination of 25 sequence types (STs) among a total of 66 isolates; STs correlated well with serotypes and allowed within-serotype differentiation for 9 of the 12 serotypes characterized. Phylogenetic analyses showed that serotypes Kentucky and Newport could each be separated into two distinct, statistically well supported evolutionary lineages. Our results show that a three-gene sequence typing scheme allows for accurate serotype prediction and for limited subtype discrimination among clinically relevant serotypes of Salmonella. Three-gene sequence typing also supports the notion that Salmonella serotypes represent both monophyletic and polyphyletic lineages. PMID:16081897

  20. Serology of oral Actinobacillus actinomycetemcomitans and serotype distribution in human periodontal disease.

    PubMed Central

    Zambon, J J; Slots, J; Genco, R J

    1983-01-01

    Actinobacillus actinomycetemcomitans from the human oral cavity was serologically characterized with rabbit antisera to the type strain NCTC 9710; a number of reference strains, including Y4, ATCC 29522, ATCC 29523, ATCC 29524, NCTC 9709; and our own isolates representative of each of 10 biotypes. Using immunoabsorbed antisera, we identified three distinct serotypes by immunodiffusion and indirect immunofluorescence. Serotype a was represented by ATCC 29523 and SUNYaB 75; serotype b was represented by ATCC 29522 and Y4; and serotype c was represented by NCTC 9710 and SUNYaB 67. Indirect immunofluorescence revealed no reaction between the three A. actinomycetemcomitans serotype-specific antisera and 62 strains representing 23 major oral bacterial species. Distinct from the serotype antigens were at least one A. actinomycetemcomitans species common antigen and an antigen shared with other Actinobacillus species, Haemophilus aphrophilus, and Haemophilus paraphrophilus. All serotype a A. actinomycetemcomitans strains failed to ferment xylose, whereas all serotype b organisms fermented xylose. Serotype c included xylose-positive as well as xylose-negative strains. A total of 301 isolates of A. actinomycetemcomitans from the oral cavity of 74 subjects were serologically categorized by indirect immunofluorescence with serotype-specific rabbit antisera. Each patient harbored only one serotype of A. actinomycetemcomitans. Fourteen healthy subjects, five diabetics, and seventeen adult periodontitis patients exhibited serotypes a and b in approximately equal frequency, whereas serotype c was found less frequently. In contrast, in 29 localized juvenile periodontitis patients, the incidence of serotype b was approximately two times higher than that of serotypes a or c, suggesting a particularly high periodontopathic potential of A. actinomycetemcomitans serotype b strains. In subjects infected with A. actinomycetemcomitans, serum antibodies were detected to the serotype

  1. Multiple mating reveals complex patterns of assortative mating by personality and body size.

    PubMed

    Montiglio, Pierre-Olivier; Wey, Tina W; Chang, Ann T; Fogarty, Sean; Sih, Andrew

    2016-01-01

    Understanding patterns of non-random mating is central to predicting the consequences of sexual selection. Most studies quantifying assortative mating focus on testing for correlations among partners' phenotypes in mated pairs. Few studies have distinguished between assortative mating arising from preferences for similar partners (expressed by all or a subset of the population) vs. from phenotypic segregation in the environment. Also, few studies have assessed the robustness of assortative mating against temporal changes in social conditions. We tracked multiple matings by stream water striders (Aquarius remigis) across variable social conditions to investigate mating patterns by both body size and behavioural type (personality). We documented temporal changes in partner availability and used a mixed model approach to analyse individual behaviours and changes in mating status recorded on an hourly basis. We assessed whether all or only a subset of individuals in the population expressed a tendency to mate with similar phenotypes. Our analyses took into account variation in the level of competition and in the phenotypes of available partners. Males and females exhibited significant assortative mating by body size: the largest males and females, and the smallest males and females mated together more often than random. However, individuals of intermediate size were equally likely to mate with small, intermediate or large partners. Individuals also displayed two contrasting patterns of assortative mating by personality (activity level). Individuals generally mated preferentially with partners of similar activity level. However, beyond that general trend, individuals with more extreme personalities tended to exhibit disassortative mating: the most active males mated disproportionately with less active females and the least active males tended to mate with more active females. Our analyses thus revealed multiple, distinct patterns of nonrandom mating. These mating

  2. Persistent colonization of 2 hospital water supplies by L. pneumophila strains through 7 years--sequence-based typing and serotyping as useful tools for a complex risk analysis.

    PubMed

    Pancer, Katarzyna; Matuszewska, Renata; Bartosik, Marta; Kacperski, Krzysztof; Krogulska, Bożena

    2013-01-01

    Contamination with Legionella spp. of hot water system (HWS) in hospitals is a considerable problem and elimination of bacteria poses difficulties. Obligatory control of Legionella spp. in hospital HWS was implemented in Poland in 2008y. After that, Legionella spp. has been isolated repeatedly from HWS of the majority of hospitals. The aim of our study was to confirm the permanent colonization with Legionella spp. of 2 hospital HWSs based on the antigenic (serogroup/subgroups) and genetic properties (SBT, rtxA) of L.pneumophila strains isolated in 2004-2011. The dynamic of L.pneumophila population was also examined due to methods of disinfections applied during 7 years. Totally, 134 environmental samples were collected from two hospitals in 2004-2011 (118 from HWSs). During the study disinfection by chlorine dioxide was implemented in both hospitals, while thermal shock was added in the hospital A. Isolated L.pneumophila were serogrouped (105 strains) using Dresden MAb Panel, genotyped by sequence based typing (53) and by harboring of rtxA gene (58 isolates). Legionella spp. were still presented in both systems after 7 years. Exactly the same strains (ST1, ST87, ST114, ST992) were found in the hospital B. While changes of L.pneumophila population were observed in the hospital A: strains still occurred after 7 years (ST835 Sg6, ST114 Sg6); modified antigenic properties (ST835 - Sg12 vs. Sg6); eliminated or maybe not detected (ST81, ST838, ST959). Moreover, the majority of examined strains ST1 (Sg1, OLDA) harboured rtxA gene (hospital B). Our results and data in the EWGLI SBT base indicated higher risk of Legionella infection in the hospital B than A--because of heavy colonization with L.pneumophila ST1. The risk assessment of Legionella infection based only on technical parameters, extent of colonization/contamination level may be not completed. It should be supplemented with the additional examination: serotyping, genotyping and virulence testing of isolated

  3. Serotype-specific neutralizing antibody epitopes of human adenovirus type 3 (HAdV-3) and HAdV-7 reside in multiple hexon hypervariable regions.

    PubMed

    Qiu, Hongling; Li, Xiao; Tian, Xingui; Zhou, Zhichao; Xing, Ke; Li, Haitao; Tang, Ni; Liu, Wenkuan; Bai, Peisheng; Zhou, Rong

    2012-08-01

    Human adenovirus types 3 and 7 (HAdV-3 and HAdV-7) occur epidemically and contribute greatly to respiratory diseases, but there is no currently available licensed recombinant HAdV-3/HAdV-7 bivalent vaccine. Identification of serotype-specific neutralizing antibody (NAb) epitopes for HAdV-3 and HAdV-7 will be beneficial for development of recombinant HAdV-3/HAdV-7 bivalent vaccines. In this study, four NAb epitopes within hexon hypervariable regions (HVRs) were predicted for HAdV-3 and HAdV-7, respectively, by using bioinformatics. Eight hexon chimeric adenovirus vectors with the alternation of only one predicted neutralizing epitope were constructed. Further in vitro and in vivo neutralization assays indicated that E2 (residing in HVR2) and E3 (residing in HVR5) are NAb epitopes for HAdV-7, and E3 plays a more important role in generating NAb responses. Cross-neutralization assays indicated that all four predicted epitopes, R1 to R4, are NAb epitopes for HAdV-3, and R1 (residing in HVR1) plays the most important role in generating NAb responses. Humoral immune responses elicited by the recombinant rAdH7R1 (containing the R1 epitope) were significantly and durably suppressed by HAdV-3-specific NAbs. Surprisingly, the rAdΔE3GFP-specific neutralizing epitope responses induced by rAdMHE3 (R3 replaced by E3) and rAdMHE4 (R4 replaced by E4) were weaker than those of rAdMHE1 (R1 replaced by E1) or rAdMHE2 (R2 relaced by E2) in vitro and in vivo. Furthermore, rAdMHE4 replicated more slowly in HEp-2 cells, and the final yield was about 10-fold lower than that of rAdΔE3GFP. The current findings contribute not only to the development of new adenovirus vaccine candidates, but also to the construction of new gene delivery vectors.

  4. Hepatitis C virus (HCV) core serotypes in chronic HCV infection.

    PubMed Central

    Mondelli, M U; Cerino, A; Bono, F; Cividini, A; Maccabruni, A; Aricò, M; Malfitano, A; Barbarini, G; Piazza, V; Minoli, L

    1994-01-01

    Recently, two distinct hepatitis C virus (HCV) serologic types have been identified on the basis of amino acid variations in the core region. The two serologic types can readily discriminate between genotypes I-II-V (serotype 1) and III-IV (serotype 2), according to the Okamoto classification. We compared HCV core serotyping with genotyping with sera from 363 anti-HCV-positive patients (309 HCV RNA positive by PCR) using a synthetic core peptide-based enzyme immunoassay and PCR amplification of core region sequences with type-specific primers, respectively. Serologic responses to HCV serotypes were successfully identified in 164 (45%) patients, of whom 153 were viremic. Eighty-nine patients had evidence of exposure to serotype 1: 8 of these were infected with genotype I, 50 were infected with genotype II, 2 were infected with genotype III, 7 were infected with genotype V, 13 had infections with mixed genotypes, 3 were infected with an indeterminate genotype, and 6 were nonviremic. Seventy-four patients had been exposed to serotype 2: 64 were infected with genotype III, 3 were infected with mixed genotypes, 2 were infected with an indeterminate genotype, and 5 were nonviremic. The serum of one patient, infected with genotype III, showed reactivity to both serotypes. Comparative evaluation of HCV core region serotyping and genotyping with sera from 294 viremic patients infected with a known HCV genotype showed a remarkable concordance between HCV core region genotyping and serotyping, with only 2 apparently discordant serum samples (both from patients with genotype III infection) of 148 (1.4%) successfully serotyped samples. Serotype 1 infection was more frequently observed in patients with overt chronic liver disease and accounted for all successfully serotyped samples from intravenous drug abusers. In contrast, serotype 2 was more prevalent in subjects with biochemically silent HCV infection (alanine aminotransferase, < 45 U/liter), in agreement with previous

  5. Porcine rotaviruses antigenically related to human rotavirus serotypes 1 and 2.

    PubMed Central

    Bellinzoni, R B; Mattion, N M; Matson, D O; Blackhall, J; La Torre, J L; Scodeller, E A; Urasawa, S; Taniguchi, K; Estes, M K

    1990-01-01

    Fecal samples from rotavirus-infected piglets were characterized by a serotyping enzyme-linked immunosorbent assay (ELISA) by using monoclonal antibodies (MAbs) specific to human serotypes 1, 2, 3, and 4 (D. O. Matson, M. K. Estes, J. W. Burns, H. B. Greenberg, K. Taniguchi, and S. Urasawa, submitted for publication). Rotavirus in 19 of 25 specimens tested from two herds of pigs from Buenos Aires province, Argentina, were classified antigenically as follows: one serotype 1, four serotype 2, two serotype 3, and no serotype 4. Six specimens reacted with both serotype 1 and 2 MAbs, and viruses in six specimens probably belonged to other serotypes because they reacted only with a VP7 common epitope MAb. Two porcine rotavirus fecal samples found to contain both serotype 1 and 2 viruses by the MAb-based test and one found to contain a serotype 2 virus were grown in tissue culture. When plaque-purified preparations of these tissue culture-adapted viruses were analyzed in the serotyping ELISA, the C60 and C86 preparations reacted only as serotype 1 viruses, indicating that the original fecal samples, which showed multiple VP7 reactivities, were heterogeneous and apparently contained two types of viruses. Testing of plaque-purified C134 virus confirmed its serotype 2 reactivity. The MAb-based serotype designations of these viruses also were confirmed by using a neutralization immunoperoxidase focus reduction assay. This is the first report of the occurrence of serotype 1 and 2 rotaviruses in animals. The MAbs originally developed to serotype human rotaviruses can be utilized to type animal rotaviruses. PMID:2157739

  6. Mating type-specific cell-cell recognition of Saccharomyces cerevisiae: cell wall attachment and active sites of a- and alpha-agglutinin.

    PubMed Central

    Cappellaro, C; Baldermann, C; Rachel, R; Tanner, W

    1994-01-01

    Mating type-specific agglutination of Saccharomyces cerevisiae a and alpha cells depends on the heterophilic interaction of two cell surface glycoproteins, the gene products of AG alpha 1 and AGA2. Evidence is presented with immunogold labelling that the alpha-agglutinin is part of the outer fimbrial cell wall coat. The a-agglutinin is bound via two S-S bridges (Cys7 and Cys50) to a cell wall component, most probably the gene product of AGA1. His273 of alpha-agglutinin has previously been shown to be essential for a- and alpha-agglutinin interaction and a model based on two opposing ion-pairs had been proposed. By site-directed mutagenesis this possibility has now been excluded. With the help of various peptides, either chemically synthesized, obtained by proteolysis of intact glycosylated a-agglutinin or prepared from a fusion protein expressed in Escherichia coli, the biologically active region of a-agglutinin was located at the C-terminus of the molecule. A peptide consisting of the C-terminal 10 amino acids (GSPIN-TQYVF) was active in nanomolar concentrations. Saccharide moieties, therefore, are not essential for the mating type-specific cell-cell interaction; glycosylated peptides are, however, four to five times more active than non-glycosylated ones. Comparisons of the recognition sequences of the S. cerevisiae agglutinins with that of the Dictyostelium contact site A glycoprotein (gp80), as well as with those of the various families of cell adhesion molecules of higher eucaryotes, have been made and are discussed. Images PMID:7957044

  7. Recurrent polymorphic mating type variation in Madagascan Bulbophyllum species (Orchidaceae) exemplifies a high incidence of auto-pollination in tropical orchids

    PubMed Central

    Gamisch, Alexander; Fischer, Gunter A; Comes, Hans Peter

    2014-01-01

    The transition from outcrossing to self-fertilization is one of the most common evolutionary changes in angiosperms. The orchid family exemplifies this evolutionary trend but, because of a general lack of large-scale surveys on auto-pollination in orchid taxa, the incidence and modes of auto-pollination among (sub)tropical orchids remain poorly known. In the present study, we assessed the frequency and mode of auto-pollination within and among species of a largely monophyletic group of Madagascan Bulbophyllum. The capacity for autonomous fruit set was investigated by bagging experiments in the greenhouse and the field, complemented with detailed floral micromorphological studies of the gynostemium. Our survey comprises 393 accessions, representing at least 78 species, and thus approximately 37% of the species diversity of the genus in the Madagascan region. Our studies revealed that mating type is directly related to gynostemium structure, most often involving the presence or absence of a physical barrier termed ‘rostellum’. As a novel and unexpected finding, we identified eight species of a single lineage of Madagascan Bulbophyllum (termed ‘clade C’), in which auto-pollinating morphs (selfers), either lacking a rostellum or (rarely) possessing a stigmatic rostellum, co-exist with their pollinator-dependent conspecifics (outcrossers). We hypothesize that auto-pollination via rostellum abortion has a simple genetic basis, and probably evolved rapidly and recurrently by subtle changes in the timing of rostellum development (heterochrony). Thus, species of clade C may have an intrinsic genetic and developmental lability toward auto-pollination, allowing rapid evolutionary response under environmental, perhaps human-disturbed conditions favouring reproductive assurance. Overall, these findings should stimulate further research on the incidence, evolution, and maintenance of mating type variation in tropical orchids, as well as how they adapt(ed) to changing

  8. Species and Mating-Type Distribution of Tapesia yallundae and T. acuformis and Occurrence of Apothecia in the U.S. Pacific Northwest.

    PubMed

    Douhan, G W; Murray, T D; Dyer, P S

    2002-07-01

    ABSTRACT Eyespot of wheat is caused by the discomycete fungi Tapesia yallundae and T. acuformis. T. yallundae is considered the most important causal agent of the disease in this region but no apothecia of either species have been found in the U.S. Pacific Northwest (PNW). Two compatible isolates of T. yallundae from the PNW were used to inoculate a field plot in the fall of 1998 and apothecia developed in the spring and fall of 2000 on standing wheat stubble. In the spring of 2000, wheat stubble from eight naturally infected fields was examined for the presence of apothecia of T. yallundae and T. acuformis. Apothecia of T. acuformis were found in two fields but no apothecia of T. yallundae were found. This is the first report of apothecia of the eyespot pathogens occurring in the PNW. Species and mating-type distribution of T. yallundae and T. acuformis in the PNW were determined from 817 isolates collected from diseased wheat over 3 years at spatial scales ranging from within fields to across states. In all, 460 isolates were identified as T. yallundae and 357 isolates were identified as T. acuformis with MAT1-1/MAT1-2 ratios not significantly different from 1:1 based on chi(2) tests at most scales tested. The apparent increase in frequency of T. acuformis from previous surveys may indicate a shift in the predominant species causing eyespot. The occurrence of apothecia under field conditions, along with the widespread distribution of mating types of both species, suggests that sexual reproduction may be occurring in both species.

  9. Recurrent polymorphic mating type variation in Madagascan Bulbophyllum species (Orchidaceae) exemplifies a high incidence of auto-pollination in tropical orchids.

    PubMed

    Gamisch, Alexander; Fischer, Gunter A; Comes, Hans Peter

    2014-06-01

    The transition from outcrossing to self-fertilization is one of the most common evolutionary changes in angiosperms. The orchid family exemplifies this evolutionary trend but, because of a general lack of large-scale surveys on auto-pollination in orchid taxa, the incidence and modes of auto-pollination among (sub)tropical orchids remain poorly known. In the present study, we assessed the frequency and mode of auto-pollination within and among species of a largely monophyletic group of Madagascan Bulbophyllum. The capacity for autonomous fruit set was investigated by bagging experiments in the greenhouse and the field, complemented with detailed floral micromorphological studies of the gynostemium. Our survey comprises 393 accessions, representing at least 78 species, and thus approximately 37% of the species diversity of the genus in the Madagascan region. Our studies revealed that mating type is directly related to gynostemium structure, most often involving the presence or absence of a physical barrier termed 'rostellum'. As a novel and unexpected finding, we identified eight species of a single lineage of Madagascan Bulbophyllum (termed 'clade C'), in which auto-pollinating morphs (selfers), either lacking a rostellum or (rarely) possessing a stigmatic rostellum, co-exist with their pollinator-dependent conspecifics (outcrossers). We hypothesize that auto-pollination via rostellum abortion has a simple genetic basis, and probably evolved rapidly and recurrently by subtle changes in the timing of rostellum development (heterochrony). Thus, species of clade C may have an intrinsic genetic and developmental lability toward auto-pollination, allowing rapid evolutionary response under environmental, perhaps human-disturbed conditions favouring reproductive assurance. Overall, these findings should stimulate further research on the incidence, evolution, and maintenance of mating type variation in tropical orchids, as well as how they adapt(ed) to changing

  10. Different mating-type-regulated genes affect the DNA repair defects of Saccharomyces RAD51, RAD52 and RAD55 mutants.

    PubMed

    Valencia-Burton, Maria; Oki, Masaya; Johnson, Jean; Seier, Tracey A; Kamakaka, Rohinton; Haber, James E

    2006-09-01

    Saccharomyces cerevisiae cells expressing both a- and alpha-mating-type (MAT) genes (termed mating-type heterozygosity) exhibit higher rates of spontaneous recombination and greater radiation resistance than cells expressing only MATa or MATalpha. MAT heterozygosity suppresses recombination defects of four mutations involved in homologous recombination: complete deletions of RAD55 or RAD57, an ATPase-defective Rad51 mutation (rad51-K191R), and a C-terminal truncation of Rad52, rad52-Delta327. We investigated the genetic basis of MAT-dependent suppression of these mutants by deleting genes whose expression is controlled by the Mata1-Matalpha2 repressor and scoring resistance to both campothecin (CPT) and phleomycin. Haploid rad55Delta strains became more damage resistant after deleting genes required for nonhomologous end-joining (NHEJ), a process that is repressed in MATa/MATalpha cells. Surprisingly, NHEJ mutations do not suppress CPT sensitivity of rad51-K191R or rad52-Delta327. However, rad51-K191R is uniquely suppressed by deleting the RME1 gene encoding a repressor of meiosis or its coregulator SIN4; this effect is independent of the meiosis-specific homolog, Dmc1. Sensitivity of rad52-Delta327 to CPT was unexpectedly increased by the MATa/MATalpha-repressed gene YGL193C, emphasizing the complex ways in which MAT regulates homologous recombination. The rad52-Delta327 mutation is suppressed by deleting the prolyl isomerase Fpr3, which is not MAT regulated. rad55Delta is also suppressed by deletion of PST2 and/or YBR052C (RFS1, rad55 suppressor), two members of a three-gene family of flavodoxin-fold proteins that associate in a nonrandom fashion with chromatin. All three recombination-defective mutations are made more sensitive by deletions of Rad6 and of the histone deacetylases Rpd3 and Ume6, although these mutations are not themselves CPT or phleomycin sensitive.

  11. Restriction endonuclease analysis and plasmid profiling of Actinobacillus pleuropneumoniae serotype 7 strains.

    PubMed

    Wards, B J; Joyce, M A; Carman, M; Hilbink, F; deLisle, G W

    1998-01-16

    Seventeen serotype 7 Actinobacillus pleuropneumoniae strains isolated in New Zealand and A. pleuropneumoniae serotypes 1-12 reference strains were typed by restriction endonuclease analysis of chromosomal DNA and plasmid profiling. All serotype 7 strains produced similar DNA cleavage patterns and were significantly different to other reference serotype strains. Minor differences in the cleavage patterns enabled the 17 serotype 7 strains to be grouped into seven profiles. Plasmids were identified in all but three strains but the banding patterns did not account for the differences in the chromosomal profiles. The study showed that restriction endonuclease analysis and plasmid profiling are useful in epidemiological studies of porcine pleuropneumonia.

  12. Antibiofilm Activity of Actinobacillus pleuropneumoniae Serotype 5 Capsular Polysaccharide

    PubMed Central

    Karwacki, Michael T.; Kadouri, Daniel E.; Bendaoud, Meriem; Izano, Era A.; Sampathkumar, Vandana; Inzana, Thomas J.; Kaplan, Jeffrey B.

    2013-01-01

    Cell-free extracts isolated from colony biofilms of Actinobacillus pleuropneumoniae serotype 5 were found to inhibit biofilm formation by Staphylococcus aureus, S. epidermidis and Aggregatibacter actinomycetemcomitans, but not by A. pleuropneumoniae serotype 5 itself, in a 96-well microtiter plate assay. Physical and chemical analyses indicated that the antibiofilm activity in the extract was due to high-molecular-weight polysaccharide. Extracts isolated from a mutant strain deficient in the production of serotype 5 capsular polysaccharide did not exhibit antibiofilm activity. A plasmid harboring the serotype 5 capsule genes restored the antibiofilm activity in the mutant extract. Purified serotype 5 capsular polysaccharide also exhibited antibiofilm activity against S. aureus. A. pleuropneumoniae wild-type extracts did not inhibit S. aureus growth, but did inhibit S. aureus intercellular adhesion and binding of S. aureus cells to stainless steel surfaces. Furthermore, polystyrene surfaces coated with A. pleuropneumoniae wild-type extracts, but not with capsule-mutant extracts, resisted S. aureus biofilm formation. Our findings suggest that the A. pleuropneumoniae serotype 5 capsule inhibits cell-to-cell and cell-to-surface interactions of other bacteria. A. pleuropneumoniae serotype 5 capsular polysaccharide is one of a growing number of bacterial polysaccharides that exhibit broad-spectrum, nonbiocidal antibiofilm activity. Future studies on these antibiofilm polysaccharides may uncover novel functions for bacterial polysaccharides in nature, and may lead to the development of new classes of antibiofilm agents for industrial and clinical applications. PMID:23691104

  13. Mutations in deoxyribonucleotide biosynthesis pathway cause spreading of silencing across heterochromatic barriers at the mating-type region of the fission yeast.

    PubMed

    Singh, Gurjeet; Klar, Amar J S

    2008-02-01

    The mat2,3-region of Schizosaccharomyces pombe is flanked by two inverted repeat elements, IRL and IRR, which define the boundaries of the silent domain resulting from heterochromatin assembly in the region. We employed a genetic screen to isolate factors whose mutations allowed spreading of heterochromatin across boundary elements. Surprisingly, this screen revealed that mutations in the genes required for deoxyribonucleotide biosynthesis, cdc22 (encoding the large subunit of ribonucleotide reductase) and tds1 (putative thymidylate synthase), cause silencing of marker genes inserted outside of the silent domain. Chromatin-immunoprecipitation analysis showed that histone H3 lysine 9 methylation modification, an epigenetic mark associated with gene silencing, is enriched by two- to three-fold in the cdc22 mutant as compared to the level found in the wild-type strain in regions outside the silent domain. The spreading of heterochromatin across barriers required functional Atf1/Pcr1, ATF-CREB family proteins, but not the RNA-interference Dcr1, Ago1, or Rdp1 factors, previously implicated in silencing. These results implicate the deoxyribonucleotide biosynthesis pathway in limiting epigenetic controls at barrier elements at the mating-type region, but the mechanism remains unknown.

  14. Identification of a dengue virus type 2 (DEN-2) serotype-specific B-cell epitope and detection of DEN-2-immunized animal serum samples using an epitope-based peptide antigen.

    PubMed

    Wu, Han-Chung; Jung, Mei-Ying; Chiu, Chien-Yu; Chao, Ting-Ting; Lai, Szu-Chia; Jan, Jia-Tsrong; Shaio, Men-Fang

    2003-10-01

    In this study, a serotype-specific monoclonal antibody (mAb), D(2) 16-1 (Ab4), against dengue virus type 2 (DEN-2) was generated. The specificity of Ab4, which recognized DEN-2 non-structural protein 1, was determined by ELISA, immunofluorescence and immunoblotting analyses. The serotype-specific B-cell epitope of Ab4 was identified further from a random phage-displayed peptide library; selected phage clones reacted specifically with Ab4 and did not react with other mAbs. Immunopositive phage clones displayed a consensus motif, His-Arg/Lys-Leu/Ile, and a synthetic peptide corresponding to the phage-displayed peptide bound specifically to Ab4. The His and Arg residues in this epitope were found to be crucial for peptide binding to Ab4 and binding activity decreased dramatically when these residues were changed to Leu. The epitope-based synthetic peptide not only identified serum samples from DEN-2-immunized mice and rabbits by ELISA but also differentiated clearly between serum samples from DEN-2- and Japanese encephalitis virus-immunized mice. This mAb and its epitope-based peptide antigen will be useful for serologic diagnosis of DEN-2 infection. Furthermore, DEN-2 epitope identification makes it feasible to dissect antibody responses to DEN and to address the role of antibodies in the pathogenesis of primary and secondary DEN-2 infections.

  15. swi6, a gene required for mating-type switching, prohibits meiotic recombination in the mat2-mat3 "cold spot" of fission yeast.

    PubMed

    Klar, A J; Bonaduce, M J

    1991-12-01

    Mitotic interconversion of the mating-type locus (mat1) of the fission yeast Schizosaccharomyces pombe is initiated by a double-strand break at mat1. The mat2 and mat3 loci act as nonrandom donors of genetic information for mat1 switching such that switches occur primarily (or only) to the opposite mat1 allele. Location of the mat1 "hot spot" for transposition should be contrasted with the "cold spot" of meiotic recombination located within the adjoining mat2-mat3 interval. That is, meiotic interchromosomal recombination in mat2, mat3 and the intervening 15-kilobase region does not occur at all. swi2 and swi6 switching-deficient mutants possess the normal level of double-strand break at mat1, yet they fail to switch efficiently. By testing for meiotic recombination in the cold spot, we found the usual lack of recombination in a swi2 mutant but a significant level of recombination in a swi6 mutant. Therefore, the swi6 gene function is required to keep the donor loci inert for interchromosomal recombination. This finding, combined with the additional result that switching primarily occurs intrachromosomally, suggests that the donor loci are made accessible for switching by folding them onto mat1, thus causing the cold spot of recombination.

  16. DNA sequence characterization and molecular evolution of MAT1 and MAT2 mating-type loci of the self-compatible ascomycete mold Neosartorya fischeri.

    PubMed

    Rydholm, C; Dyer, P S; Lutzoni, F

    2007-05-01

    Degenerate PCR and chromosome-walking approaches were used to identify mating-type (MAT) genes and flanking regions from the homothallic (sexually self-fertile) euascomycete fungus Neosartorya fischeri, a close relative of the opportunistic human pathogen Aspergillus fumigatus. Both putative alpha- and high-mobility-group-domain MAT genes were found within the same genome, providing a functional explanation for self-fertility. However, unlike those in many homothallic euascomycetes (Pezizomycotina), the genes were not found adjacent to each other and were termed MAT1 and MAT2 to recognize the presence of distinct loci. Complete copies of putative APN1 (DNA lyase) and SLA2 (cytoskeleton assembly control) genes were found bordering the MAT1 locus. Partial copies of APN1 and SLA2 were also found bordering the MAT2 locus, but these copies bore the genetic hallmarks of pseudogenes. Genome comparisons revealed synteny over at least 23,300 bp between the N. fischeri MAT1 region and the A. fumigatus MAT locus region, but no such long-range conservation in the N. fischeri MAT2 region was evident. The sequence upstream of MAT2 contained numerous candidate transposase genes. These results demonstrate a novel means involving the segmental translocation of a chromosomal region by which the ability to undergo self-fertilization may be acquired. The results are also discussed in relation to their significance in indicating that heterothallism may be ancestral within the Aspergillus section Fumigati.

  17. Switching gene swi6, involved in repression of silent mating-type loci in fission yeast, encodes a homologue of chromatin-associated proteins from Drosophila and mammals.

    PubMed

    Lorentz, A; Ostermann, K; Fleck, O; Schmidt, H

    1994-05-27

    The switching gene swi6 of Schizosaccharomyces pombe is involved in the repression of the silent mating-type loci mat2 and mat3. We have cloned the gene by functional complementation of the switching defect of the swi6-115 mutation. DNA sequence analyses revealed an open reading frame of 984 bp coding for a putative protein of 328 amino acids (aa). The isolation of a swi6 cDNA confirmed this result. Gene replacement showed that swi6 is not essential for viability. The Swi6 protein is very hydrophilic; it contains 41% charged aa. A region of 48 aa is homologous to a sequence motif found in the chromatin-associated proteins, HP1 and Polycomb (Drosophila melanogaster), M31, M32 and M33 (mouse), and the human HSM1 protein. This motif is called chromo domain (chromatin organization modifier). Our results indicate that Swi6 is a structural component of chromatin. Swi6 may have the function to compact mat2 and mat3 into a heterochromatin-like conformation which represses the transcription of these silent cassettes.

  18. Swi6, a Gene Required for Mating-Type Switching, Prohibits Meiotic Recombination in the Mat2-Mat3 ``cold Spot'' of Fission Yeast

    PubMed Central

    Klar, AJS.; Bonaduce, M. J.

    1991-01-01

    Mitotic interconversion of the mating-type locus (mat1) of the fission yeast Schizosaccharomyces pombe is initiated by a double-strand break at mat1. The mat2 and mat3 loci act as nonrandom donors of genetic information for mat1 switching such that switches occur primarily (or only) to the opposite mat1 allele. Location of the mat1 ``hot spot'' for transposition should be contrasted with the ``cold spot'' of meiotic recombination located within the adjoining mat2-mat3 interval. That is, meiotic interchromosomal recombination in mat2, mat3 and the intervening 15-kilobase region does not occur at all. swi2 and swi6 switching-deficient mutants possess the normal level of double-strand break at mat1, yet they fail to switch efficiently. By testing for meiotic recombination in the cold spot, we found the usual lack of recombination in a swi2 mutant but a significant level of recombination in a swi6 mutant. Therefore, the swi6 gene function is required to keep the donor loci inert for interchromosomal recombination. This finding, combined with the additional result that switching primarily occurs intrachromosomally, suggests that the donor loci are made accessible for switching by folding them onto mat1, thus causing the cold spot of recombination. PMID:1783290

  19. DNA Sequence Characterization and Molecular Evolution of MAT1 and MAT2 Mating-Type Loci of the Self-Compatible Ascomycete Mold Neosartorya fischeri▿

    PubMed Central

    Rydholm, C.; Dyer, P. S.; Lutzoni, F.

    2007-01-01

    Degenerate PCR and chromosome-walking approaches were used to identify mating-type (MAT) genes and flanking regions from the homothallic (sexually self-fertile) euascomycete fungus Neosartorya fischeri, a close relative of the opportunistic human pathogen Aspergillus fumigatus. Both putative alpha- and high-mobility-group-domain MAT genes were found within the same genome, providing a functional explanation for self-fertility. However, unlike those in many homothallic euascomycetes (Pezizomycotina), the genes were not found adjacent to each other and were termed MAT1 and MAT2 to recognize the presence of distinct loci. Complete copies of putative APN1 (DNA lyase) and SLA2 (cytoskeleton assembly control) genes were found bordering the MAT1 locus. Partial copies of APN1 and SLA2 were also found bordering the MAT2 locus, but these copies bore the genetic hallmarks of pseudogenes. Genome comparisons revealed synteny over at least 23,300 bp between the N. fischeri MAT1 region and the A. fumigatus MAT locus region, but no such long-range conservation in the N. fischeri MAT2 region was evident. The sequence upstream of MAT2 contained numerous candidate transposase genes. These results demonstrate a novel means involving the segmental translocation of a chromosomal region by which the ability to undergo self-fertilization may be acquired. The results are also discussed in relation to their significance in indicating that heterothallism may be ancestral within the Aspergillus section Fumigati. PMID:17384199

  20. Position effect variegation at the mating-type locus of fission yeast: a cis-acting element inhibits covariegated expression of genes in the silent and expressed domains.

    PubMed Central

    Ayoub, N; Goldshmidt, I; Cohen, A

    1999-01-01

    Schizosaccharomyces pombe switches its mating type by transposing a copy of unexpressed genes from the respective mat2 or mat3 cassettes to mat1. The donor cassettes are located in a silent domain that is separated from the expressed mat1 cassette by the L region. We monitored the expression of ade6 from sites in the L region and examined the relationship between the expression state at these sites and at sites within the silent domain. Results indicate that: (1) the silent domain extends into the L region, but repression is gradually alleviated with increasing distance from mat2, and overexpression of swi6 enhances PEV in the L region; (2) a transcriptionally active chromatin state, associated with reporter gene expression in the L region, spreads toward the silent domain; (3) a cis-acting element, located at the junction between the L region and mat2-P, ensures repression in the silent domain, regardless of the expression state in the L region; and (4) repression in mat1-P cells is less stringently controlled than in mat1-M cells. We discuss the functional organization of the mat region and genetic elements that ensure separation between repressed and derepressed domains. PMID:10353894

  1. Position effect variegation at the mating-type locus of fission yeast: a cis-acting element inhibits covariegated expression of genes in the silent and expressed domains.

    PubMed

    Ayoub, N; Goldshmidt, I; Cohen, A

    1999-06-01

    Schizosaccharomyces pombe switches its mating type by transposing a copy of unexpressed genes from the respective mat2 or mat3 cassettes to mat1. The donor cassettes are located in a silent domain that is separated from the expressed mat1 cassette by the L region. We monitored the expression of ade6 from sites in the L region and examined the relationship between the expression state at these sites and at sites within the silent domain. Results indicate that: (1) the silent domain extends into the L region, but repression is gradually alleviated with increasing distance from mat2, and overexpression of swi6 enhances PEV in the L region; (2) a transcriptionally active chromatin state, associated with reporter gene expression in the L region, spreads toward the silent domain; (3) a cis-acting element, located at the junction between the L region and mat2-P, ensures repression in the silent domain, regardless of the expression state in the L region; and (4) repression in mat1-P cells is less stringently controlled than in mat1-M cells. We discuss the functional organization of the mat region and genetic elements that ensure separation between repressed and derepressed domains.

  2. Genome-wide identification of target genes of a mating-type α-domain transcription factor reveals functions beyond sexual development.

    PubMed

    Becker, Kordula; Beer, Christina; Freitag, Michael; Kück, Ulrich

    2015-06-01

    Penicillium chrysogenum is the main industrial producer of the β-lactam antibiotic penicillin, the most commonly used drug in the treatment of bacterial infections. Recently, a functional MAT1-1 locus encoding the α-box transcription factor MAT1-1-1 was discovered to control sexual development in P. chrysogenum. As only little was known from any organism about the regulatory functions mediated by MAT1-1-1, we applied chromatin immunoprecipitation combined with next-generation sequencing (ChIP-seq) to gain new insights into the factors that influence MAT1-1-1 functions on a molecular level and its role in genome-wide transcriptional regulatory networks. Most importantly, our data provide evidence for mating-type transcription factor functions that reach far beyond their previously understood role in sexual development. These new roles include regulation of hyphal morphology, asexual development, as well as amino acid, iron, and secondary metabolism. Furthermore, in vitro DNA-protein binding studies and downstream analysis in yeast and P. chrysogenum enabled the identification of a MAT1-1-1 DNA-binding motif, which is highly conserved among euascomycetes. Our studies pave the way to a more general understanding of these master switches for development and metabolism in all fungi, and open up new options for optimization of fungal high production strains.

  3. Replication and segregation of plasmids containing cis-acting regulatory sites of silent mating-type genes in Saccharomyces cerevisiae are controlled by the SIR genes.

    PubMed Central

    Kimmerly, W J; Rine, J

    1987-01-01

    In Saccharomyces cerevisiae, two cis-acting regulatory sites called E and I flank the silent mating-type gene, HMRa, and mediate SIR-dependent transcriptional repression of the a1-a2 promoters. It has been shown previously that the E and I sites have plasmid replicator (ARS) activity. We show in this report that the ARS activity of the E and I sites is governed by the SIR genotype of the cell. In wild-type cells, a plasmid carrying the E site from HMRa (HMR E) in the vector YIp5 exhibited very high mitotic stability at a copy number of approximately 25 per cell. However, in sir2, sir3, or sir4 mutants, plasmids with HMR E had the low mitotic stability characteristic of plasmids containing ARS1, a SIR-independent replicator. Elevated mitotic stability of plasmids that carry HMR E is due to a segregation mechanism provided by SIR and HMR E. In sir2 and sir4 mutants, the plasmid copy number was significantly lowered, suggesting that these gene products also participate in the replication of plasmids carrying HMR E. The phenotype of point mutations introduced at an 11-base-pair ARS consensus sequence present at HMR E indicated that this sequence is functional but not absolutely required for autonomous replication of the plasmid and that it is not required for SIR-dependent mitotic stabilization. A plasmid carrying both a centromere and HMR E exhibited reduced mitotic stability in wild-type cells. This destabilization appeared to be due to antagonism between the segregation functions provided by the centromere and by HMR E. Images PMID:3325822

  4. Role of H- and D- MATE-Type Transporters from Multidrug Resistant Clinical Isolates of Vibrio fluvialis in Conferring Fluoroquinolone Resistance

    PubMed Central

    Mohanty, Priyabrata; Patel, Arati; Kushwaha Bhardwaj, Ashima

    2012-01-01

    Background The study seeks to understand the role of efflux pumps in multidrug resistance displayed by the clinical isolates of Vibrio fluvialis, a pathogen known to cause cholera-like diarrhoea. Methodology Two putative MATE family efflux pumps (H- and D-type) were PCR amplified from clinical isolates of V. fluvialis obtained from Kolkata, India, in 2006 and sequenced. Bioinformatic analysis of these proteins was done to predict protein structures. Subsequently, the genes were cloned and expressed in a drug hypersusceptible Escherichia coli strain KAM32 using the vector pBR322. The recombinant clones were tested for the functionality of the efflux pump proteins by MIC determination and drug transport assays using fluorimeter. Results The sequences of the genes were found to be around 99% identical to their counterparts in V. cholerae. Protein structure predicting servers TMHMM and I-TASSER depicted ten-twelve membrane helical structures for both type of pumps. Real time PCR showed that these genes were expressed in the native V. fluvialis isolates. In the drug transport assays, the V. fluvialis clinical isolates as well as recombinant E. coli harbouring the efflux pump genes showed the energy-dependent and sodium ion-dependent drug transport activity. KAM32 cells harbouring the recombinant plasmids showed elevated MIC to the fluoroquinolones, norfloxacin and ciprofloxacin but H-type pumps VCH and VFH from V. cholerae and V. fluvialis respectively, showed decreased MIC to aminoglycosides like gentamicin, kanamycin and streptomycin. Decrease in MIC was also observed for acriflavin, ethidium bromide, safranin and nalidixic acid. Significance Increased resistance towards fluoroquinolones exhibited due to these efflux pumps from multidrug resistant clinical isolates of V. fluvialis implies that treatment procedure may become more elaborate for this simple but highly infectious disease. To the best of our knowledge, this is the first report of cloning and

  5. Revisitingmolecular serotyping of Streptococcus pneumoniae

    PubMed Central

    2015-01-01

    Background Ninety-two Streptococcus pneumoniae serotypes have been described so far, but the pneumococcal conjugate vaccine introduced in the Brazilian basic vaccination schedule in 2010 covers only the ten most prevalent in the country. Pneumococcal serotype-shifting after massive immunization is a major concern and monitoring this phenomenon requires efficient and accessible serotyping methods. Pneumococcal serotyping based on antisera produced in animals is laborious and restricted to a few reference laboratories. Alternatively, molecular serotyping methods assess polymorphisms in the cps gene cluster, which encodes key enzymes for capsular polysaccharides synthesis in pneumococci. In one such approach, cps-RFLP, the PCR amplified cps loci are digested with an endonuclease, generating serotype-specific fingerprints on agarose gel electrophoresis. Methods In this work, in silico and in vitro approaches were combined to demonstrate that XhoII is the most discriminating endonuclease for cps-RFLP, and to build a database of serotype-specific fingerprints that accommodates the genetic diversity within the cps locus of 92 known pneumococci serotypes. Results The expected specificity of cps-RFLP using XhoII was 76% for serotyping and 100% for serogrouping. The database of cps-RFLP fingerprints was integrated to Molecular Serotyping Tool (MST), a previously published web-based software for molecular serotyping. In addition, 43 isolates representing 29 serotypes prevalent in the state of Minas Gerais, Brazil, from 2007 to 2013, were examined in vitro; 11 serotypes (nine serogroups) matched the respective in silico patterns calculated for reference strains. The remaining experimental patterns, despite their resemblance to their expected in silico patterns, did not reach the threshold of similarity score to be considered a match and were then added to the database. Conclusion The cps-RFLP method with XhoII outperformed the antisera-based and other molecular serotyping

  6. Field Evaluation of Culture plus Latex Sweep Serotyping for Detection of Multiple Pneumococcal Serotype Colonisation in Infants and Young Children

    PubMed Central

    Turner, Paul; Turner, Claudia; Jankhot, Auscharee; Phakaudom, Kawalee; Nosten, Francois; Goldblatt, David

    2013-01-01

    Background Nasopharyngeal swab (NPS) culture by World Health Organisation (WHO) methodology underestimates multiple pneumococcal serotype colonisation compared to a simple culture and latex sweep method. The impacts of this on descriptions of pneumococcal serotype distributions and colonisation dynamics in infancy are not clear. Methods 8,736 NPS collected from infants enrolled into a longitudinal study were processed to evaluate the field utility of the latex sweep method. 1,107 had previously been cultured by WHO methodology. Additionally, colonisation results were compared in 100 matched pairs of infants, where swabs from an individual were cultured either by WHO or latex sweep method. Results In 1,107 swabs cultured by both methods, the latex sweep method was three times more likely to detect colonisation with multiple pneumococcal serotypes than the WHO method (p<0.001). At least one common serotype was identified in 91.2% of swabs from which typeable pneumococci were detected by both methods. Agreement improved with increasing colonisation density (p = 0.03). Estimates of age at first pneumococcal acquisition and colonisation duration were not affected by culture/serotyping method. However, a greater number of serotype carriage episodes were detected in infants cultured by latex sweep (p = 0.03). The overall rate of non-vaccine type pneumococcal acquisition was also greater in infants cultured by latex sweep (p = 0.04). Conclusions Latex sweep serotyping was feasible to perform on a large specimen collection. Multiple serotype colonisation detection was significantly improved compared with WHO methodology. However, use of the latex sweep method is unlikely to significantly alter colonisation study serotype distribution or colonisation dynamics results. PMID:23844133

  7. Emerging Opportunities for Serotypes of Botulinum Neurotoxins

    PubMed Central

    Peng Chen, Zhongxing; Morris, J. Glenn; Rodriguez, Ramon L.; Shukla, Aparna Wagle; Tapia-Núñez, John; Okun, Michael S.

    2012-01-01

    Background: Two decades ago, botulinum neurotoxin (BoNT) type A was introduced to the commercial market. Subsequently, the toxin was approved by the FDA to address several neurological syndromes, involving muscle, nerve, and gland hyperactivity. These syndromes have typically been associated with abnormalities in cholinergic transmission. Despite the multiplicity of botulinal serotypes (designated as types A through G), therapeutic preparations are currently only available for BoNT types A and B. However, other BoNT serotypes are under study for possible clinical use and new clinical indications; Objective: To review the current research on botulinum neurotoxin serotypes A-G, and to analyze potential applications within basic science and clinical settings; Conclusions: The increasing understanding of botulinal neurotoxin pathophysiology, including the neurotoxin’s effects on specific neuronal populations, will help us in tailoring treatments for specific diagnoses, symptoms and patients. Scientists and clinicians should be aware of the full range of available data involving neurotoxin subtypes A-G. PMID:23202312

  8. Two HAP2-GCS1 homologs responsible for gamete interactions in the cellular slime mold with multiple mating types: Implication for common mechanisms of sexual reproduction shared by plants and protozoa and for male-female differentiation.

    PubMed

    Okamoto, Marina; Yamada, Lixy; Fujisaki, Yukie; Bloomfield, Gareth; Yoshida, Kentaro; Kuwayama, Hidekazu; Sawada, Hitoshi; Mori, Toshiyuki; Urushihara, Hideko

    2016-07-01

    Fertilization is a central event in sexual reproduction, and understanding its molecular mechanisms has both basic and applicative biological importance. Recent studies have uncovered the molecules that mediate this process in a variety of organisms, making it intriguing to consider conservation and evolution of the mechanisms of sexual reproduction across phyla. The social amoeba Dictyostelium discoideum undergoes sexual maturation and forms gametes under dark and humid conditions. It exhibits three mating types, type-I, -II, and -III, for the heterothallic mating system. Based on proteome analyses of the gamete membranes, we detected expression of two homologs of the plant fertilization protein HAP2-GCS1. When their coding genes were disrupted in type-I and type-II strains, sexual potency was completely lost, whereas disruption in the type-III strain did not affect mating behavior, suggesting that the latter acts as female in complex organisms. Our results demonstrate the highly conserved function of HAP2-GCS1 in gamete interactions and suggest the presence of additional allo-recognition mechanisms in D. discoideum gametes. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. The Widespread Multidrug-Resistant Serotype O12 Pseudomonas aeruginosa Clone Emerged through Concomitant Horizontal Transfer of Serotype Antigen and Antibiotic Resistance Gene Clusters.

    PubMed

    Thrane, Sandra Wingaard; Taylor, Véronique L; Freschi, Luca; Kukavica-Ibrulj, Irena; Boyle, Brian; Laroche, Jérôme; Pirnay, Jean-Paul; Lévesque, Roger C; Lam, Joseph S; Jelsbak, Lars

    2015-09-22

    O12 and how this clone type has emerged. This study shows that evolution of MDR O12 strains involved a switch from an ancestral O4 serotype to O12. Serotype switching was the result of horizontal transfer and genetic recombination of lipopolysaccharide (LPS) biosynthesis genes originating from an MDR taxonomic outlier P. aeruginosa strain. Moreover, the recombination event also resulted in acquisition of antibiotic resistance genes. These results impact on our understanding of MDR outbreak strain and serotype evolution and can potentially assist in better monitoring and prevention. Copyright © 2015 Thrane et al.

  10. First report of an outbreak of pneumonia caused by Streptococcus pneumoniae serotype 6A.

    PubMed

    Prebil, Karla; Beović, Bojana; Paragi, Metka; Seme, Katja; Kastrin, Tamara; Plesničar, Blanka Kores; Petek, Bojana; Martinčič, Žiga

    2016-01-01

    Five patients in a geropsychiatric unit of a psychiatric hospital became abruptly ill with pneumonia caused by Streptococcus pneumoniae serotype 6A. Four other residents were colonized with the same serotype, which has previously not been reported in association with pneumonia outbreaks. Furthermore, serotype 6A is not included in all vaccine types, which may be important for the choice of vaccine in some settings. All isolates showed identical pulsed-field gel electrophoresis restriction patterns.

  11. Low-impact mating system

    NASA Technical Reports Server (NTRS)

    Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Le, Thang D. (Inventor); Morales, Ray H. (Inventor); Robertson, Brandan R. (Inventor)

    2009-01-01

    An androgynous mating system for mating two exoatmospheric space modules comprising a first mating assembly capable of mating with a second mating assembly; a second mating assembly structurally identical to said first mating assembly, said first mating assembly comprising; a load ring; a plurality of load cell subassemblies; a plurality of actuators; a base ring; a tunnel; a closed loop control system; one or more electromagnets; and one or more striker plates, wherein said one or more electomagnets on said second mating assembly are capable of mating with said one or more striker plates on said first mating assembly, and wherein said one or more striker plates is comprised of a plate of predetermined shape and a 5-DOF mechanism capable of maintaining predetermined contact requirements during said mating of said one or more electromagnets and said one or more striker plates.

  12. Genomes of Ashbya Fungi Isolated from Insects Reveal Four Mating-Type Loci, Numerous Translocations, Lack of Transposons, and Distinct Gene Duplications

    PubMed Central

    Dietrich, Fred S.; Voegeli, Sylvia; Kuo, Sidney; Philippsen, Peter

    2013-01-01

    The filamentous fungus Ashbya gossypii is a cotton pathogen transmitted by insects. It is readily grown and manipulated in the laboratory and is commercially exploited as a natural overproducer of vitamin B2. Our previous genome analysis of A. gossypii isolate ATCC10895, collected in Trinidad nearly 100 years ago, revealed extensive synteny with the Saccharomyces cerevisiae genome, leading us to use it as a model organism to understand the evolution of filamentous growth. To further develop Ashbya as a model system, we have investigated the ecological niche of A. gossypii and isolated additional strains and a sibling species, both useful in comparative analysis. We isolated fungi morphologically similar to A. gossypii from different plant-feeding insects of the suborder Heteroptera, generated a phylogenetic tree based on rDNA-ITS sequences, and performed high coverage short read sequencing with one A. gossypii isolate from Florida, a new species, Ashbya aceri, isolated in North Carolina, and a genetically marked derivative of ATCC10895 intensively used for functional studies. In contrast to S. cerevisiae, all strains carry four not three mating type loci, adding a new puzzle in the evolution of Ashbya species. Another surprise was the genome identity of 99.9% between the Florida strain and ATCC10895, isolated in Trinidad. The A. aceri and A. gossypii genomes show conserved gene orders rearranged by eight translocations, 90% overall sequence identity, and fewer tandem duplications in the A. aceri genome. Both species lack transposable elements. Finally, our work identifies plant-feeding insects of the suborder Heteroptera as the most likely natural reservoir of Ashbya, and that infection of cotton and other plants may be incidental to the growth of the fungus in its insect host. PMID:23749448

  13. Evidence of the accumulation of allele-specific non-synonymous substitutions in the young region of recombination suppression within the mating-type chromosomes of Neurospora tetrasperma

    PubMed Central

    Whittle, C A; Johannesson, H

    2011-01-01

    Currently, little is known about the origin and early evolution of sex chromosomes. This is largely due to the fact that ancient non-recombining sex chromosomes are highly degenerated, and thus provide little information about the early genomic events in their evolution. The Neurospora tetrasperma mating-type (mat) chromosomes contain a young (<6 Mya) and large region (>6.6 Mb) of suppressed recombination, thereby providing a model system to study early stages of sex chromosome evolution. Here, we examined alleles of 207 genes located on the N. tetrasperma mat a and mat A chromosomes to test for signs of genomic alterations at the protein level in the young region of recombination suppression. We report that the N. tetrasperma mat a and mat A chromosomes have each independently accumulated allele-specific non-synonymous codon substitutions in a time-dependent, and gene-specific manner in the recombinationally suppressed region. In addition, examination of the ratio (ω) of non-synonymous substitutions (dN) to synonymous substitutions (dS) using maximum likelihood analyses, indicates that such changes are associated with relaxed purifying selection, a finding consistent with genomic degeneration. We also reveal that sex specific biases in mutation rates or selection pressures are not necessary for genomic alterations in sex chromosomes, and that recombination suppression in itself is sufficient to explain these results. The present findings extend our current understanding of genomic events associated within the young region of recombination suppression in these fungal sex-regulating chromosomes. PMID:21386869

  14. Gene genealogies indicates abundant gene conversions and independent evolutionary histories of the mating-type chromosomes in the evolutionary history of Neurospora tetrasperma

    PubMed Central

    2010-01-01

    Background The self-fertile filamentous ascomycete Neurospora tetrasperma contains a large (~7 Mbp) and young (< 6 MYA) region of suppressed recombination within its mating-type (mat) chromosomes. The objective of the present study is to reveal the evolutionary history, including key genomic events, associated with the various regions of the mat chromosomes among ten strains representing all the nine known species (lineages) contained within the N. tetrasperma species complex. Results Comparative analysis of sequence divergence among alleles of 24 mat-linked genes (mat A and mat a) indicates that a large region of suppressed recombination exists within the mat chromosome for each of nine lineages of N. tetrasperma sensu latu. The recombinationally suppressed region varies in size and gene composition among lineages, and is flanked on both ends by normally recombining regions. Genealogical analyses among lineages reveals that eight gene conversion events have occurred between homologous mat A and mat a-linked alleles of genes located within the region of restricted recombination during the evolutionary history of N. tetrasperma. Conclusions We conclude that the region of suppressed recombination in the mat chromosomes has likely been subjected to independent contraction and/or expansion during the evolutionary history of the N. tetrasperma species complex. Furthermore, we infer that gene conversion events are likely a common phenomenon within this recombinationally suppressed genomic region. We argue that gene conversions might provide an efficient mechanism of adaptive editing of functional genes, including the removal of deleterious mutations, within the young recombinationally suppressed region of the mat chromosomes. PMID:20673371

  15. Evidence for minority male mating success and minority female mating disadvantage in Drosophila ananassae.

    PubMed

    Som, Arundhati; Singh, Bashisth N

    2005-03-31

    Frequency-dependent mating success was tested for three pairs of wild-type and mutant strains of Drosophila ananassae, MY and yellow body color (y), PN and claret eye color (ca), and TIR and cut wing (ct). The two strains of each pair were chosen for their approximately equal mating propensities. Multiple-choice experiments, using different experimental procedures, were employed. The tests were carried out by direct observation in Elens-Wattiaux mating chambers with five different sex ratios (4:16, 8:12, 10:10, 12:8, and 16:4). There was no assortative mating and sexual isolation between the strains, based on 2 x 2 contingency chi2 analysis and isolation estimate values. One-sided rare male mating advantages were found in two experiments, one for ca males and the other for wild-type males (TIR). However, no advantage was found for rare males in the experiment with MY and y flies. Mating disadvantages for rare females were found for sex-linked mutants (y and ct). Two different observational methods (removal or direct observation of mating pairs) imparted no overall significant effects on the outcome of the frequency-dependent mating tests.

  16. Purification and characterization of serotype 6 fimbriae from Bordetella pertussis and comparison of their properties with serotype 2 fimbriae.

    PubMed Central

    Cowell, J L; Zhang, J M; Urisu, A; Suzuki, A; Steven, A C; Liu, T; Liu, T Y; Manclark, C R

    1987-01-01

    Fimbriae were removed from Bordetella pertussis (serotype 1.3.6) by mechanical shearing and purified by precipitation with ammonium sulfate, pH-dependent precipitation at pH 7.4, followed by two successive extractions of the precipitated fimbriae with 4 M urea. By electron microscopy, the precipitated fimbriae appeared as aggregated bundles of long, relatively straight filaments which were disaggregated to individual flexuous filaments at pH 10.5. These purified fimbriae were identified as serotype 6 agglutinogens, since antibody to the purified fimbriae agglutinated B. pertussis strains serotyped as 1.3.6, 1.2.3.6, or 1.2.3.4.6 but did not agglutinate strains of serotype 1.2.3.4, 1.2.3, or 1.3. In contrast, antibody to serotype 2 fimbriae only agglutinated B. pertussis strains containing serotype 2 agglutinogen. Purified type 6 and 2 fimbriae were found to be weakly cross-reactive by enzyme-linked immunosorbent assay, using polyclonal antibody to each type of fimbria. In an immunoblot assay, polyclonal antibodies to a 22,000-dalton subunit of fimbriae from B. bronchiseptica reacted strongly with the type 2 fimbrial subunit of B. pertussis, but only weakly with the type 6 subunit. When subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protein subunit of the type 6 fimbriae migrated with a molecular weight of 21,500, whereas the type 2 fimbrial subunit had a molecular weight of 22,000. The two types of subunits had similar amino acid compositions and showed amino-terminal sequence homology in 15 of 21 amino acids. The amino-terminal amino acid sequences of the B. pertussis fimbriae were distinct from those reported for fimbriae from other gram-negative bacteria. Neither the type 6 nor the type 2 fimbriae caused hemagglutination when assayed with several types of erythrocytes. Images PMID:2881893

  17. Firefly Mating Algorithm for Continuous Optimization Problems

    PubMed Central

    Ritthipakdee, Amarita; Premasathian, Nol; Jitkongchuen, Duangjai

    2017-01-01

    This paper proposes a swarm intelligence algorithm, called firefly mating algorithm (FMA), for solving continuous optimization problems. FMA uses genetic algorithm as the core of the algorithm. The main feature of the algorithm is a novel mating pair selection method which is inspired by the following 2 mating behaviors of fireflies in nature: (i) the mutual attraction between males and females causes them to mate and (ii) fireflies of both sexes are of the multiple-mating type, mating with multiple opposite sex partners. A female continues mating until her spermatheca becomes full, and, in the same vein, a male can provide sperms for several females until his sperm reservoir is depleted. This new feature enhances the global convergence capability of the algorithm. The performance of FMA was tested with 20 benchmark functions (sixteen 30-dimensional functions and four 2-dimensional ones) against FA, ALC-PSO, COA, MCPSO, LWGSODE, MPSODDS, DFOA, SHPSOS, LSA, MPDPGA, DE, and GABC algorithms. The experimental results showed that the success rates of our proposed algorithm with these functions were higher than those of other algorithms and the proposed algorithm also required fewer numbers of iterations to reach the global optima. PMID:28808442

  18. Virus recovery rates for wild-type and live-attenuated vaccine strains of African horse sickness virus serotype 7 in orally infected South African Culicoides species.

    PubMed

    Venter, G J; Paweska, J T

    2007-12-01

    Previously reported virus recovery rates from Culicoides (Avaritia) imicola Kieffer and Culicoides (Avaritia) bolitinos Meiswinkel (Diptera, Ceratopogonidae) orally infected with vaccine strain of African horse sickness virus serotype 7 (AHSV-7) were compared with results obtained from concurrently conducted oral infections with five recent AHSV-7 isolates from naturally infected horses from various localities in South Africa. Culicoides were fed sheep bloods spiked with 10(7.6) TCID(50)/mL of a live-attenuated vaccine strain AHSV-7, and with five field isolates in which virus titre in the bloodmeals ranged from 10(7.1) to 10(8.2) TCID(50)/mL). After an extrinsic incubation of 10 days at 23.5 degrees C, virus recovery rates were significantly higher in C. imicola (13.3%) and C. bolitinos (4.2%) infected with the live-attenuated virus than in midges infected with any of the field isolates. The virus recovery rates for the latter groups ranged from 0% to 9.5% for C. imicola and from 0% to 1.5% for C. bolitinos. The C. imicola population at Onderstepoort was significantly more susceptible to infection with AHSV-7 isolated at Onderstepoort than to the virus strains isolated from other localities. Results of this study suggest that tissue culture attenuation of AHSV-7 does not reduce its ability to orally infect competent Culicoides species and may even lead to enhanced replication in the vector. Furthermore, oral susceptibility in a midge population appears to vary for geographically distinct isolates of AHSV-7.

  19. Molecular diagnosis of non-serotypeable Shigella spp.: problems and prospects.

    PubMed

    Muthuirulandi Sethuvel, Dhiviya Prabaa; Devanga Ragupathi, Naveen Kumar; Anandan, Shalini; Walia, Kamini; Veeraraghavan, Balaji

    2017-02-01

    It is not always possible to identify Shigella serogroups/serotypes by biochemical properties alone. Specific identification requires serotyping. Occasionally, isolates that resemble Shigella spp. biochemically, but are non-agglutinable with available antisera, have been observed. Several mechanisms have been reported to limit the efficiency of the serotyping assay. Serotype conversion is a major mechanism in Shigella spp. to escape protective host immune responses. This easy conversion through significant modification of the O-antigen backbone results in different serotypes, which makes laboratory identification difficult. Furthermore, members of the family Enterobacteriaceae are closely related and there is antigenic cross-over (intra- and inter-specific cross-reaction) which affects the agglutination reaction. The performance of the available methods for identification of non-serotypeable Shigella is discussed here, and reveals them to be non-reliable. This shows a need for an alternative method for identification and typing of Shigella spp.

  20. Mating genes of the Trichophyton mentagrophytes complex.

    PubMed

    Kano, Rui; Kawasaki, Masako; Mochizuki, Takashi; Hiruma, Masatarou; Hasegawa, Atsuhiko

    2012-03-01

    The mating type (-)-specific gene of the alpha-box and the mating type (+)-specific gene of the high-mobility group (HMG) DNA-binding domain were confirmed in zoophilic dematophytes of Arthroderma simii and A. vanbreuseghemii. The sequence of the alpha-box gene was 1,375 bp, containing 2 exons (from 172 to 463 bp and from 513 to 1,375 bp) in the A. simii (-) mating type strain and 1,380 bp, containing 2 exons (from 177 to 468 bp and from 518 to 1,380 bp) in the A. vanbreuseghemii (-) mating type strain. The sequence of the HMG gene was 1,871 bp, containing 2 exons (from 181 to 362 bp and from 426 to 1,440 bp, coding a protein of 398 amino acids) in the A. simii (+) mating type strain and 1,811 bp containing 2 exons (from 158 to 339 bp and from 403 to 1,381 bp, coding a protein of 386 amino acids) in the A. vanbreuseghemii (+) mating type strain. Of 15 animal isolates and 72 human isolates examined, the alpha-box gene was detected in five of the animal isolates and in none of the human isolates, while the HMG gene was detected in the other 10 of the animal isolates and in all of the human isolates. Phylogenetic analysis of the alpha-box and HMG genes of Trichophyton mentagrophytes complex strains and the Microsporum gypseum strain revealed that these strains were divided into 4 clusters; the first cluster consisting of A. vanbreuseghemii and the isolates from animals and humans, the second cluster consisting of A. simii, the third cluster consisting of A. benhamiae and the fourth cluster consisting of M. gypseum. These results indicate that anthropophilic T. mentagrophytes evolved from the A. vanbreuseghemii (+) mating strain.

  1. Salmonella enterica Serotype 4,5,12:i:−, an Emerging Salmonella Serotype That Represents Multiple Distinct Clones ▿ †

    PubMed Central

    Soyer, Y.; Moreno Switt, A.; Davis, M. A.; Maurer, J.; McDonough, P. L.; Schoonmaker-Bopp, D. J.; Dumas, N. B.; Root, T.; Warnick, L. D.; Gröhn, Y. T.; Wiedmann, M.

    2009-01-01

    The prevalence, among human clinical cases, of Salmonella enterica serotype 4,5,12:i:−, a serotype antigenically similar to Salmonella enterica serotype Typhimurium but lacking second-phase flagellar antigens, has increased considerably over the last 10 years. To probe the evolution and ecology of this emerging serotype, we characterized 190 Salmonella isolates initially classified as Salmonella serotypes 4,5,12:i:− (n = 90) and Typhimurium (n = 100) and obtained from various sources in the United States and Spain. These isolates were characterized into six sequence types (determined by multilocus sequence typing [MLST]) and 79 pulsed-field gel electrophoresis types. The majority of Salmonella serotype 4,5,12:i:− and Typhimurium isolates (85 and 84 isolates, respectively) represented a single MLST type. Existing genome information revealed different genome deletions (which included genes responsible for phase 2 flagellum expression) in four Spanish Salmonella serotype 4,5,12:i:− isolates and one U.S. Salmonella serotype 4,5,12:i:− isolate. Fifty-nine isolates of both serotypes, representing different sources and geographical locations as well as different molecular subtypes, were thus screened for the presence of six genes and one specific region, all of which were previously found to show variable presence among Salmonella serotype 4,5,12:i:− and Typhimurium strains. All Salmonella serotype 4,5,12:i:− isolates lacked the phase 2 flagella genes fljA and fljB, which were present in all Salmonella serotype Typhimurium isolates. While all Spanish Salmonella serotype 4,5,12:i:− isolates carried the same deletion surrounding fljAB, all but two U.S. isolates showed a different genomic deletion; the two atypical U.S. isolates represented the “Spanish” deletion genotype and a unique deletion genotype. Salmonella serotype 4,5,12:i:− thus appears to represent at least two common clones, which cannot easily be differentiated with standard diagnostic

  2. Serotype IX, a Proposed New Streptococcus agalactiae Serotype▿

    PubMed Central

    Slotved, Hans-Christian; Kong, Fanrong; Lambertsen, Lotte; Sauer, Susanne; Gilbert, Gwendolyn L.

    2007-01-01

    We identified three isolates of Streptococcus agalactiae (group B streptococcus [GBS]), of human origin, which failed to react with antisera against any of the nine known GBS serotypes. Polyclonal rabbit antisera raised against these isolates and standard GBS typing sera were used in capillary precipitation and Ouchterlony tests to compare the strains with known GBS serotype reference strains. All three previously nontypeable isolates reacted with all three new antisera, producing lines of identity in the Ouchterlony test. Weak cross-reactions with antisera against several GBS serotypes were observed but were removed by absorption with corresponding antigens. The new antisera were used to test 227 GBS isolates that had been nontypeable or difficult to type using standard antisera. Of these, five reacted with the new antisera. These results suggested that all eight isolates belong to the previously unrecognized GBS serotype. They were tested by Western blotting for the Cα and Cβ proteins and by PCR to identify molecular serotypes and surface protein antigen genes. Two segments of the cps gene cluster (3′ end of cpsE-cpsF and 5′ end of cpsG, approximately 700 bp; 3′ end of cpsH and 5′ end of cpsM, approximately 560 bp) were sequenced. All eight isolates expressed Cα, and seven expressing the Cβ protein and the corresponding genes, bca and bac, respectively, were identified. They all share the same, unique partial cps sequence. These results indicate that these eight isolates represent a new S. agalactiae serotype, which we propose should be designated serotype IX. PMID:17634306

  3. Clonal distribution of pneumococcal serotype 19F isolates from Ghana.

    PubMed

    Sparding, Nadja; Dayie, Nicholas T K D; Mills, Richael O; Newman, Mercy J; Dalsgaard, Anders; Frimodt-Møller, Niels; Slotved, Hans-Christian

    2015-04-01

    Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. Pneumococcal strains are classified according to their capsular polysaccharide and more than 90 different serotypes are currently known. In this project, three distinct groups of pneumococcal carriage isolates from Ghana were investigated; isolates from healthy children in Tamale and isolates from both healthy and children attending the outpatient department at a hospital in Accra. The isolates were previously identified and characterized by Gram staining, serotyping and susceptibility to penicillin. In this study, isolates of the common serotype 19F were further investigated by Multi-Locus Sequence Typing (MLST). Overall, 14 different Sequence Types (STs) were identified by MLST, of which nine were novel based on the international MLST database. Two clones within serotype 19F seem to circulate in Ghana, a known ST (ST 4194) and a novel ST (ST 9090). ST 9090 was only found in healthy children in Accra, whereas ST 4194 was found equally in all children studied. In the MLST database, other isolates of ST 4194 were also associated with serotype 19F, and these isolates came from other West African countries. The majority of isolates were penicillin intermediate resistant. In conclusion, two clones within serotype 19F were found to be dominating in pneumococcal carriage in Accra and Tamale in Ghana. Furthermore, it seems as though the clonal distribution of serotype 19F may be different from what is currently known in Ghana in that many new clones were identified. This supports the importance of continued monitoring of pneumococcal carriage in Ghana and elsewhere when vaccines, e.g., PCV-13, have been introduced to monitor the possible future spread of antimicrobial resistant clones.

  4. Novel Levofloxacin-Resistant Multidrug-Resistant Streptococcus pneumoniae Serotype 11A Isolates, South Korea

    PubMed Central

    Park, Miey; Kim, Hyun Soo; Kim, Han-Sung; Park, Ji Young; Song, Wonkeun; Cho, Hyoun Chan

    2016-01-01

    Of 608 Streptococcus pneumoniae clinical strains isolated at a hospital in South Korea during 2009–2014, sixteen (2.6%) were identified as levofloxacin resistant. The predominant serotype was 11A (9 isolates). Two novel sequence types of multidrug-resistant S. pneumoniae with serotype 11A were identified, indicating continuous diversification of resistant strains. PMID:27767906

  5. Actinobacillus actinomycetemcomitans serotype e--biotypes, genetic diversity and distribution in relation to periodontal status.

    PubMed

    Doğan, B; Saarela, M H; Jousimies-Somer, H; Alaluusua, S; Asikainen, S

    1999-04-01

    Actinobacillus actinomycetemcomitans isolates from 356 individuals were screened for identification of serotype e in order to investigate its distribution in relation to periodontal status. From subjects with serotype e, 1-6 isolates per subject (n = 61) were genotyped using arbitrarily primed-polymerase chain reaction (AP-PCR) and apaH gene polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis to determine the genetic heterogeneity within the serotype. Furthermore, one serotype e strain per subject was tested for fermentation of 8 carbohydrates for biotyping. Among patients with adult periodontitis (n = 219), localized juvenile periodontitis (n = 55) and other forms of early-onset periodontitis (n = 18) serotypes b, a and c, respectively, were the most frequently detected serotypes. Non-periodontitis subjects (n = 64) were predominantly colonized with serotype c. Serotype e was found in 30 (14%) adult periodontitis patients, 2 (11%) early-onset periodontitis patients and in 5 (8%) non-periodontitis individuals, but in none of the 55 localized juvenile periodontitis patients. AP-PCR distinguished 3 and apaH gene PCR-RFLP analysis 2 genotypes among the 61 A. actinomycetemcomitans serotype e isolates, one genotype per subject. The AP-PCR genotypes 1 and 3 represented the apaH genotype 1 and the AP-PCR genotype 2 the apaH genotype 2. On the basis of variable fermentation of galactose and xylose, 3 biotypes among A. actinomycetemcomitans serotype e were established. Contrary to the absence of A. actinomycetemcomitans serotype e in localized juvenile periodontitis patients, its detection frequency was comparable among other forms of periodontitis and periodontal health. Clinical serotype e isolates form at least 2 genetic types and 3 biotypes.

  6. Ureaplasma urealyticum serotypes in urinary tract disease.

    PubMed Central

    Hewish, M J; Birch, D F; Fairley, K F

    1986-01-01

    Ureaplasma urealyticum cultures from 124 patients with urinary tract disease were serotyped by indirect immunofluorescence, using antisera to serotypes I to VIII. A similar range of serotypes was recovered from first-voided, midstream, and bladder-aspiration (SPA) urine, upper urinary tract samples, and vaginal swabs. Serotype VI was predominant (44/124) among the samples, whereas serotypes V (1/124 samples) and VII (0/124 samples) were uncommon. Twenty of 124 cultures contained more than one serotype, and three cultures were untypeable. Serotypes cultured from bladder urine were also present in vaginal and urethral samples, although these samples often carried additional serotypes. Consecutive SPA samples from the same patient invariably contained the same serotype, whereas some consecutive midstream urine samples showed a loss or gain of serotypes with time. One patient carried the same serotype in SPA urine over a period of 13 months. The pattern of serotypes recovered from the urinary tract was similar irrespective of the sampling site, the site of infection, the clinical diagnosis and renal function of the patient, and the presence or absence of other microorganisms. Colonization above the urethra and association with urinary tract disease appeared to be serotype independent. PMID:3700599

  7. Production of latex agglutination reagents for pneumococcal serotyping

    PubMed Central

    2013-01-01

    Background The current ‘gold standard’ for serotyping pneumococci is the Quellung test. This technique is laborious and requires a certain level of training to correctly perform. Commercial pneumococcal latex agglutination serotyping reagents are available, but these are expensive. In-house production of latex agglutination reagents can be a cost-effective alternative to using commercially available reagents. This paper describes a method for the production and quality control (QC) of latex reagents, including problem solving recommendations, for pneumococcal serotyping. Results Here we describe a method for the production of latex agglutination reagents based on the passive adsorption of antibodies to latex particles. Sixty-five latex agglutination reagents were made using the PneuCarriage Project (PCP) method, of which 35 passed QC. The other 30 reagents failed QC due to auto-agglutination (n=2), no reactivity with target serotypes (n=8) or cross-reactivity with non-target serotypes (n=20). Dilution of antisera resulted in a further 27 reagents passing QC. The remaining three reagents passed QC when prepared without centrifugation and wash steps. Protein estimates indicated that latex reagents that failed QC when prepared using the PCP method passed when made with antiserum containing ≤ 500 μg/ml of protein. Sixty-one nasopharyngeal isolates were serotyped with our in-house latex agglutination reagents, with the results showing complete concordance with the Quellung reaction. Conclusions The method described here to produce latex agglutination reagents allows simple and efficient serotyping of pneumococci and may be applicable to latex agglutination reagents for typing or identification of other microorganisms. We recommend diluting antisera or removing centrifugation and wash steps for any latex reagents that fail QC. Our latex reagents are cost-effective, technically undemanding to prepare and remain stable for long periods of time, making them ideal for

  8. Production of latex agglutination reagents for pneumococcal serotyping.

    PubMed

    Ortika, Belinda D; Habib, Maha; Dunne, Eileen M; Porter, Barbara D; Satzke, Catherine

    2013-02-05

    The current 'gold standard' for serotyping pneumococci is the Quellung test. This technique is laborious and requires a certain level of training to correctly perform. Commercial pneumococcal latex agglutination serotyping reagents are available, but these are expensive. In-house production of latex agglutination reagents can be a cost-effective alternative to using commercially available reagents. This paper describes a method for the production and quality control (QC) of latex reagents, including problem solving recommendations, for pneumococcal serotyping. Here we describe a method for the production of latex agglutination reagents based on the passive adsorption of antibodies to latex particles. Sixty-five latex agglutination reagents were made using the PneuCarriage Project (PCP) method, of which 35 passed QC. The other 30 reagents failed QC due to auto-agglutination (n=2), no reactivity with target serotypes (n=8) or cross-reactivity with non-target serotypes (n=20). Dilution of antisera resulted in a further 27 reagents passing QC. The remaining three reagents passed QC when prepared without centrifugation and wash steps. Protein estimates indicated that latex reagents that failed QC when prepared using the PCP method passed when made with antiserum containing ≤ 500 μg/ml of protein. Sixty-one nasopharyngeal isolates were serotyped with our in-house latex agglutination reagents, with the results showing complete concordance with the Quellung reaction. The method described here to produce latex agglutination reagents allows simple and efficient serotyping of pneumococci and may be applicable to latex agglutination reagents for typing or identification of other microorganisms. We recommend diluting antisera or removing centrifugation and wash steps for any latex reagents that fail QC. Our latex reagents are cost-effective, technically undemanding to prepare and remain stable for long periods of time, making them ideal for use in low-income countries.

  9. AAV Hybrid Serotypes: Improved Vectors for Gene Delivery

    PubMed Central

    Choi, Vivian W.; McCarty, Douglas M.; Samulski, R. Jude

    2006-01-01

    In recent years, significant efforts have been made on studying and engineering adeno-associated virus (AAV) capsid, in order to increase efficiency in targeting specific cell types that are non-permissive to wild type (wt) viruses and to improve efficacy in infecting only the cell type of interest. With our previous knowledge of the viral properties of the naturally occurring serotypes and the elucidation of their capsid structures, we can now generate capsid mutants, or hybrid serotypes, by various methods and strategies. In this review, we summarize the studies performed on AAV retargeting, and categorize the available hybrid serotypes to date, based on the type of modification: 1) transcapsidation, 2) adsorption of bi-specific antibody to capsid surface, 3) mosaic capsid, and 4) chimeric capsid. Not only these hybrid serotypes could achieve high efficiency of gene delivery to a specific targeted cell type, which can be better-tailored for a particular clinical application, but also serve as a tool for studying AAV biology such as receptor binding, trafficking and genome delivery into the nucleus. PMID:15975007

  10. Antibodies against certain bluetongue and epizootic haemorrhagic disease viral serotypes in Indonesian ruminants.

    PubMed

    Sendow, I; Daniels, P W; Cybinski, D H; Young, P L; Ronohardjo, P

    1991-06-01

    The orbiviruses contain several important viruses of livestock including bluetongue (BT) and epizootic haemorrhagic disease of deer (EHD) which share some group antigens. Preliminary screening of sera for antibodies to orbiviruses by the agar gel immunodiffusion (AGID) test has previously revealed widespread infections with the BT group in Indonesia. However serum neutralization (SN) tests give a more accurate estimate of exposure to each serotype in the BT and EHD groups, and in this study were applied to sera that had reacted previously in the AGID test. Five different serotypes of BT and one serotype of EHD virus were studied. Reactors to BT serotype 20 were the most prevalent, followed by EHD type 5 and BT types 21, 12, 1 and 17. Antibodies against BT serotype 20 were present in cattle, buffaloes, goats and sheep, but were most common in buffaloes. Buffaloes showed the highest exposure to the BT serotypes tested. Antibody to EHD type 5 occurred most frequently in cattle. Antibodies against all BT and EHD serotypes tested were found in buffaloes and cattle while goats had antibodies against BT types 20, 21 and EHD type 5 and sheep had antibodies only against BT type 20.

  11. Antibiotic resistance and putative virulence factors of Serratia marcescens with respect to O and K serotypes.

    PubMed

    Aucken, H M; Pitt, T L

    1998-12-01

    Serratia marcescens serotypes O6:K14, O8:K14 and O28:K28 are common in the natural environment, but rare in hospitals. Serotypes O14:K14 and O27:K14 predominate among clinical strains, but not in the environment, suggesting that the latter serotypes may be more suited for survival in the clinical setting. Consequently, 469 epidemiologically distinct strains of S. marcescens were tested for various putative virulence factors and analysed for associations with serotype. The factors positively associated with serotype O14:K14 were agglutination of five different species of red blood cells and expression of type 1 fimbriae. These were found in 63% and 53% of O14:K14 strains, respectively, compared with 7% and 12% of the three 'environmental serotypes'. Almost a quarter of the collection expressed the mannose-resistant haemagglutinin indicative of type 3 fimbriae, but this was not associated with any serotype. The production of DNAase, haemolysin, lipase, lecithinase, proteases and siderophores was almost universal and showed no serotype correlations. Almost half of the strains (46%) were resistant to serum and serotypes O27:K14 and O6:K14 were strongly associated with this characteristic. Serotype O27:K14 was also associated with higher proportions of antibiotic-resistant strains than other serotypes, but the same was not true of serotype O14:K14. All three 'environmental serotypes' were associated with low frequencies of antibiotic resistance; <12% were resistant to gentamicin, carbenicillin or piperacillin, or any combination of these three, compared with 20-25% of O14:K14 strains and >42-51% of O27:K14 strains. Pigment production was strongly associated with serotype. None of the O14:K14 or O27:K14 strains produced prodigiosin, but frequencies for the three 'environmental serotypes' ranged from 31% of O28:K28 strains to 85% of O6:K14 strains. The results of this study suggest that the adherence capability of S. marcescens strains may play a role in the colonisation

  12. A molecular scheme for Yersinia enterocolitica patho-serotyping derived from genome-wide analysis.

    PubMed

    Garzetti, Debora; Susen, Rosa; Fruth, Angelika; Tietze, Erhard; Heesemann, Jürgen; Rakin, Alexander

    2014-05-01

    Yersinia enterocolitica is a food-borne, gastro-intestinal pathogen with world-wide distribution. Only 11 serotypes have been isolated from patients, with O:3, O:9, O:8 and O:5,27 being the serotypes most commonly associated with human yersiniosis. Serotype is an important characteristic of Y. enterocolitica strains, allowing differentiation for epidemiology, diagnosis and phylogeny studies. Conventional serotyping, performed by slide agglutination, is a tedious and laborious procedure whose interpretation tends to be subjective, leading to poor reproducibility. Here we present a PCR-based typing scheme for molecular identification and patho-serotyping of Y. enterocolitica. Genome-wide comparison of Y. enterocolitica sequences allowed analysis of the O-antigen gene clusters of different serotypes, uncovering their formerly unknown genomic locations, and selection of targets for serotype-specific amplification. Two multiplex PCRs and one additional PCR were designed and tested on various reference strains and isolates from different origins. Our genotypic assay proved to be highly specific for identification of Y. enterocolitica species, discrimination between virulent and non-virulent strains, distinguishing the main human-related serotypes, and typing of conventionally untypeable strains. This genotyping scheme could be applied in microbiology laboratories as an alternative or complementary method to the traditional phenotypic assays, providing data for epidemiological studies. Copyright © 2013 Elsevier GmbH. All rights reserved.

  13. Genetic Characteristics and Multiple-PCR Development for Capsular Identification of Specific Serotypes of Campylobacter jejuni

    PubMed Central

    Liang, Hao; Zhang, Aiyu; Gu, Yixin; You, Yuanhai; Zhang, Jianzhong; Zhang, Maojun

    2016-01-01

    The polysaccharide capsule (CPS) of Campylobacter jejuni is a virulence factor linked to cell surface carbohydrate diversity which mainly determines the serotypes. Thirty-four CPS gene cluster structures have been published and some of them can be distinguished by multiple-PCR. Penner serotypes HS1/44c, HS2, HS4c, HS19, HS23/36c and HS41 are markers for Guillain—Barré syndrome (GBS). The capsules may contribute to GBS susceptibility. Analysis of 18 CPS loci revealed high gene content diversity and a mosaic nature of the capsule loci, which are possibly due to gene gain/loss events, and demonstrated a high degree of conservation of genes within serotypes/serotype complexes. A method of multiple-PCR was developed to distinguish five specific serotypes and three GBS-related serotypes. Primers specific for each capsule type were designed on the basis of paralogs or a unique DNA region of the CPS locus. The multiple-PCR can distinguish the eight serotypes in two PCRs with sensitivity and specificity of 100% using 227 strains of known Penner type. The multiple-PCR method will help to distinguish serotypes simply and rapidly. PMID:27788180

  14. The Mating Type Locus (MAT) and Sexual Reproduction of Cryptococcus heveanensis: Insights into the Evolution of Sex and Sex-Determining Chromosomal Regions in Fungi

    PubMed Central

    Metin, Banu; Findley, Keisha; Heitman, Joseph

    2010-01-01

    Mating in basidiomycetous fungi is often controlled by two unlinked, multiallelic loci encoding homeodomain transcription factors or pheromones/pheromone receptors. In contrast to this tetrapolar organization, Cryptococcus neoformans/Cryptococcus gattii have a bipolar mating system, and a single biallelic locus governs sexual reproduction. The C. neoformans MAT locus is unusually large (>100 kb), contains >20 genes, and enhances virulence. Previous comparative genomic studies provided insights into how this unusual MAT locus might have evolved involving gene acquisitions into two unlinked loci and fusion into one contiguous locus, converting an ancestral tetrapolar system to a bipolar one. Here we tested this model by studying Cryptococcus heveanensis, a sister species to the pathogenic Cryptococcus species complex. An extant sexual cycle was discovered; co-incubating fertile isolates results in the teleomorph (Kwoniella heveanensis) with dikaryotic hyphae, clamp connections, septate basidia, and basidiospores. To characterize the C. heveanensis MAT locus, a fosmid library was screened with C. neoformans/C. gattii MAT genes. Positive fosmids were sequenced and assembled to generate two large probably unlinked MAT gene clusters: one corresponding to the homeodomain locus and the other to the pheromone/receptor locus. Strikingly, two divergent homeodomain genes (SXI1, SXI2) are present, similar to the bE/bW Ustilago maydis paradigm, suggesting one or the other homeodomain gene was recently lost in C. neoformans/C. gattii. Sequencing MAT genes from other C. heveanensis isolates revealed a multiallelic homeodomain locus and at least a biallelic pheromone/receptor locus, similar to known tetrapolar species. Taken together, these studies reveal an extant C. heveanensis sexual cycle, define the structure of its MAT locus consistent with tetrapolar mating, and support the proposed evolutionary model for the bipolar Cryptococcus MAT locus revealing transitions in sexuality

  15. Autocrine response of Schizosaccharomyces pombe haploid cells to mating pheromones.

    PubMed

    Kitamura, K; Nakamura, T; Miki, F; Shimoda, C

    1996-09-15

    The mating response of the fission yeast Schizosaccharomyces pombe is mediated by mating pheromones, M-factor and P-factor, produced by h- and h+ cells, respectively. When the M-factor receptor (Map3) was ectopically expressed in h- cells lacking the P-factor receptor (Mam2), they acquired mating competence in response to M-factor which they secreted. The autocrine response to P-factor in h- cells was so weak that mating competence was not acquired, although expression of the pheromone-responsive gene matl-Pm was detected. These observations support the notion that the intensity of cellular response to mating phermones is different between h- and h+ cells, although downstream pathways of the pheromone receptors are shared by the two mating types.

  16. Mate Selection and Mating Behaviour in Spider Crabs

    NASA Astrophysics Data System (ADS)

    Jones, D. R.; Hartnoll, R. G.

    1997-02-01

    Female spider crabs can only mate after the terminal moult, which means that they must either mate whilst soft-shelled after moulting, or subsequently when hard-shelled. There is evidence that some, at least, do both, whereas the majority of crabs mate in only one or other of these states. The mating behaviour, and the means of detecting receptive females, have been studied in a spider crab, Inachus dorsettensis. In this species, mating is predominantly hard-shelled, and receptive females are recognized by their emission of chemical pheromones. The implications of the behaviour patterns for male mating efficiency, sperm competition and female reproductive success are discussed. Mate selection and mating behaviour in other spider crabs are compared with I. dorsettensis. Reasons for similarities and differences are reviewed.

  17. Salmonella enterica prevalence and serotype distribution in swine at slaughter

    USDA-ARS?s Scientific Manuscript database

    The objective of this cross-sectional study was to analyze data available from multiple studies conducted by our research team estimating the prevalence of S. enterica, and the serotype distribution in swine at slaughter, based on different sample types. A total of 1,110 pigs from three large capaci...

  18. Clinical and microbiological characterization of serotype 6D pneumococcal infections in South Korea.

    PubMed

    Cheong, Hee Jin; Song, Joon Young; Choi, Min Joo; Jeon, Ji Ho; Kang, Seong Hee; Jeong, Eun Joo; Noh, Ji Yun; Kim, Woo Joo

    2016-08-01

    The prevalence of Serotype 6D Streptococcus pneumoniae was reported relatively high in South Korea. Since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), serotype replacement was observed. This study was designed to better clarify genetic diversity of pneumococcal serotype 6D and its clinical characteristics after introduction of PCV7 in 2000. We performed serotyping analysis with 1298 pneumococcal isolates from clinical specimens in South Korea from 2004 to 2011. Multilocus sequence typing was performed, and minimal inhibitory concentration was determined for the available serotype 6D and nontypeable (NT) pneumococcal isolates during the 2006-2007 period. The proportion of serotype 6D pneumococci increased from 0.8% (2004-2007) to 2.9% (2008-2011) of all clinical pneumococcal isolates, accounting for 14.9% of serogroup 6 pneumococci in South Korea. NT pneumococci markedly increased to 13.3% during 2006-2007 in advance of the increase in serotype 6D. Among the 26 available serotype 6D pneumococcal isolates, ST282 was predominant (23 isolates, 88.5%). The STs of NT pneumococci (26 isolates) were diverse, but clonal complex 271 was the dominant clone. The oral penicillin non-susceptibility rate was 92.3% (24 among 26 isolates) for both serotype 6D and NT pneumococci. The ceftriaxone non-susceptibility rates of serotype 6D and NT pneumococci were 7.7% and 3.8%, respectively. ST228(6D) strain expanded, particularly among old adults with comorbidities in South Korea. Both antibiotic and PCV7 pressure might have contributed to the selective increase of NT and serotype 6D pneumococci. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  19. Gene expression response of Salmonella enterica serotype Enteritidis phage type 8 to the subinhibitory concentrations of the plant - derived compounds, trans-cinnamaldehyde, and eugenol

    USDA-ARS?s Scientific Manuscript database

    Background: Salmonella Enteritidis phage type 8 (PT8) is a major poultry-associated Salmonella strain implicated in foodborne outbreaks in the United States. We previously reported that two GRAS-status, plant-derived compounds, trans-cinnamaldehyde (TC) and eugenol (EG) significantly reduced S. Ent...

  20. Molecular Genetics of Mating Recognition in Basidiomycete Fungi

    PubMed Central

    Casselton, Lorna A.; Olesnicky, Natalie S.

    1998-01-01

    The recognition of compatible mating partners in the basidiomycete fungi requires the coordinated activities of two gene complexes defined as the mating-type genes. One complex encodes members of the homeobox family of transcription factors, which heterodimerize on mating to generate an active transcription regulator. The other complex encodes peptide pheromones and 7-transmembrane receptors that permit intercellular signalling. Remarkably, a single species may have many thousands of cross-compatible mating types because the mating-type genes are multiallelic. Different alleles of both sets of genes are necessary for mating compatibility, and they trigger the initial stages of sexual development—the formation of a specialized filamentous mycelium termed the dikaryon, in which the haploid nuclei remain closely associated in each cell but do not fuse. Three species have been taken as models to describe the molecular structure and organization of the mating-type loci and the genes sequestered within them: the pathogenic smut fungus Ustilago maydis and the mushrooms Coprinus cinereus and Schizophyllum commune. Topics addressed in this review are the roles of the mating-type gene products in regulating sexual development, the molecular basis for multiple mating types, and the molecular interactions that permit different allelic products of the mating type genes to be discriminated. Attention is drawn to the remarkable conservation in the mechanisms that regulate sexual development in basidiomycetes and unicellular ascomycete yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, a theme which is developed in the general conclusion to include the filamentous ascomycetes Neurospora crassa and Podospora anserina. PMID:9529887

  1. Isolation and genomic characterization of SfI, a serotype-converting bacteriophage of Shigella flexneri

    PubMed Central

    2013-01-01

    Background All Shigella flexneri serotypes except serotype 6 share a common O-antigen tetrasaccharide backbone and nearly all variations between serotypes are due to glucosyl and/or O-acetyl modifications of the common O unit mediated by glycosyltransferases encoded by serotype-converting bacteriophages. Several S. flexneri serotype-converting phages including SfV, SfX, Sf6 and SfII have been isolated and characterized. However, S. flexneri serotype-converting phage SfI which encodes a type I modification of serotype 1 (1a, 1b, 1c and 1d) had not yet been characterized. Results The SfI phage was induced and purified from a S. flexneri serotype 1a clinical strain 019. Electron microscopy showed that the SfI phage has a hexagonal head and a long contractile tail, characteristic of the members of Myoviridae family. SfI can convert serotype Y to serotype 1a and serotype X to serotype 1d, but cannot convert 10 other S. flexneri serotypes (1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, Xv) tested, suggesting that SfI has a narrow host range. Similar to other S. flexneri serotype-converting phages, SfI integrates into the tRNA-thrW gene adjacent to proA of the host chromosome when lysogenized. The complete sequence of the SfI genome was 38,389 bp, encoding 66 open reading frames and two tRNA genes. Phage SfI shares significant homology with S. flexneri phage SfV, Escherichia coli prophage e14 and lambda, and is classified into the lambdoid phage family. SfI was found to use a cos mechanism for DNA packaging similar to that of phage SfV. Conclusions SfI contains features of lambdoid phages and is closely related to S. flexneri phage SfV, E. coli prophage e14 and lambda. The characterization of SfI enhances our understanding of serotype conversion of S. flexneri. PMID:23414301

  2. Food ingestion and egestion in mating reactive populations of Paramecium primaurelia.

    PubMed

    Ramoino, P

    1992-01-01

    The study of food ingestion and egestion carried out on Paramecium primaurelia mating reactive cells shows that, after their transfer into a medium with suspended particles, the complementary mating type cells exhibit very significant differences in the food vacuole formation and egestion rate. Under the same external environmental conditions, the mating type II cells form and egest a higher number of food vacuoles when compared with mating type I cells. The higher rate of food vacuole formation shown by the mating type II cells is related to their faster growth rate.

  3. Identification and Expression Analysis of MATE Genes Involved in Flavonoid Transport in Blueberry Plants

    PubMed Central

    Chen, Li; Liu, Yushan; Liu, Hongdi; Kang, Limin; Geng, Jinman; Gai, Yuzhuo; Ding, Yunlong; Sun, Haiyue; Li, Yadong

    2015-01-01

    Multidrug and toxic compound extrusion (MATE) proteins are the most recently identified family of multidrug transporters. In plants, this family is remarkably large compared to the human and bacteria counterpart, highlighting the importance of MATE proteins in this kingdom. Here 33 Unigenes annotated as MATE transporters were found in the blueberry fruit transcriptome, of which eight full-length cDNA sequences were identified and cloned. These proteins are composed of 477–517 residues, with molecular masses ~54 kDa, and theoretical isoelectric points from 5.35 to 8.41. Bioinformatics analysis predicted 10–12 putative transmembrane segments for VcMATEs, and localization to the plasma membrane without an N-terminal signal peptide. All blueberry MATE proteins shared 32.1–84.4% identity, among which VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8, and VcMATE9 were more similar to the MATE-type flavonoid transporters. Phylogenetic analysis showed VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8 and VcMATE9 clustered with MATE-type flavonoid transporters, indicating that they might be involved in flavonoid transport. VcMATE1 and VcMATE4 may be involved in the transport of secondary metabolites, the detoxification of xenobiotics, or the export of toxic cations. Real-time quantitative PCR demonstrated that the expression profile of the eight VcMATE genes varied spatially and temporally. Analysis of expression and anthocyanin accumulation indicated that there were some correlation between the expression profile and the accumulation of anthocyanins. These results showed VcMATEs might be involved in diverse physiological functions, and anthocyanins across the membranes might be mutually maintained by MATE-type flavonoid transporters and other mechanisms. This study will enrich the MATE-based transport mechanisms of secondary metabolite, and provide a new biotechonology strategy to develop better nutritional blueberry cultivars. PMID:25781331

  4. Identification and expression analysis of MATE genes involved in flavonoid transport in blueberry plants.

    PubMed

    Chen, Li; Liu, Yushan; Liu, Hongdi; Kang, Limin; Geng, Jinman; Gai, Yuzhuo; Ding, Yunlong; Sun, Haiyue; Li, Yadong

    2015-01-01

    Multidrug and toxic compound extrusion (MATE) proteins are the most recently identified family of multidrug transporters. In plants, this family is remarkably large compared to the human and bacteria counterpart, highlighting the importance of MATE proteins in this kingdom. Here 33 Unigenes annotated as MATE transporters were found in the blueberry fruit transcriptome, of which eight full-length cDNA sequences were identified and cloned. These proteins are composed of 477-517 residues, with molecular masses ~54 kDa, and theoretical isoelectric points from 5.35 to 8.41. Bioinformatics analysis predicted 10-12 putative transmembrane segments for VcMATEs, and localization to the plasma membrane without an N-terminal signal peptide. All blueberry MATE proteins shared 32.1-84.4% identity, among which VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8, and VcMATE9 were more similar to the MATE-type flavonoid transporters. Phylogenetic analysis showed VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8 and VcMATE9 clustered with MATE-type flavonoid transporters, indicating that they might be involved in flavonoid transport. VcMATE1 and VcMATE4 may be involved in the transport of secondary metabolites, the detoxification of xenobiotics, or the export of toxic cations. Real-time quantitative PCR demonstrated that the expression profile of the eight VcMATE genes varied spatially and temporally. Analysis of expression and anthocyanin accumulation indicated that there were some correlation between the expression profile and the accumulation of anthocyanins. These results showed VcMATEs might be involved in diverse physiological functions, and anthocyanins across the membranes might be mutually maintained by MATE-type flavonoid transporters and other mechanisms. This study will enrich the MATE-based transport mechanisms of secondary metabolite, and provide a new biotechonology strategy to develop better nutritional blueberry cultivars.

  5. Differential susceptibility of invasive Haemophilus influenzae serotype a and serotype b to ampicillin and other commonly prescribed antibiotics.

    PubMed

    Shuel, M; Whyte, K; Drew, T; Wylie, J; Lefebvre, B; Hoang, L; Tsang, R S W

    2014-08-01

    Haemophilus influenzae serotype a (Hia) has become an important pathogen in the post-H. influenzae serotype b (Hib) vaccine era. Antibiotic resistance in H. influenzae is a global phenomenon, but few studies have looked at antibiotic resistance profiles with regard to serotype. Invasive Hia (n = 157), noninvasive Hia (n = 2) and invasive Hib (n = 42) collected over the last two decades from three Canadian Provinces were examined for resistance to several commonly prescribed antibiotics, and sequence types (STs) were determined by MLST. Only 1·9% of Hia showed antibiotic resistance, while 31% of Hib were resistant to one or more antibiotic. Resistance to ampicillin, sulfamethoxazole-trimethoprim, chloramphenicol and tetracycline was observed, with β-lactamase-mediated ampicillin resistance being the most common. Nine STs were identified for Hia with 7 STs belonging to the same clonal complex. Ten STs were observed in Hib strains, and all of them belonged to a single clonal complex. A possible correlation between sequence type and ampicillin resistance was observed for Hib, while no correlations were observed for Hia. Despite H. influenzae serotype b (Hib) vaccine programs, invasive disease due to Hib still exists in Canada and is either second or third most common behind nontypeable and/or serotype a (Hia). Many previous studies on antibiotic resistance have focussed on respiratory isolates, and few have looked at resistance with regard to serotype. This study analysed antibiotic resistance in invasive Hia and Hib collected over 20 years from three provinces, and results found that significantly more Hib showed resistance compared to Hia. This provides a small snapshot of H. influenzae disease in Canada and highlights the importance to continually monitor antibiotic resistance profiles. © 2014 Her Majesty the Queen in Right of Canada Journal of Applied Microbiology © 2014 Society for Applied Microbiology Reproduced with the permission of the Minister

  6. Bacterial vaccines and serotype replacement: lessons from Haemophilus influenzae and prospects for Streptococcus pneumoniae.

    PubMed Central

    Lipsitch, M.

    1999-01-01

    Conjugate vaccines have reduced the incidence of invasive disease caused by Haemophilus influenzae, type b (Hib), in industrialized countries and may be highly effective against Streptococcus pneumoniae. However, the serotype specificity of these vaccines has led to concern that their use may increase carriage of and disease from serotypes not included in the vaccine. Replacement has not occurred with the use of Hib vaccines but has occurred in trials of pneumococcal vaccines. Mathematical models can be used to elucidate these contrasting outcomes, predict the conditions under which serotype replacement is likely, interpret the results of conjugate vaccine trials, design trials that will better detect serotype replacement (if it occurs), and suggest factors to consider in choosing the serotype composition of vaccines. PMID:10341170

  7. Mating pheromones of heterobasidiomycetous yeasts

    NASA Astrophysics Data System (ADS)

    Kamiya, Y.; Sakurai, A.

    1981-03-01

    Two mating pheromones, which induce mating tube formation, were isolated from Rhodosporidium toruloides (rhodotorucine A) and Tremella mesenterica (tremerogen A-10). These mating pheromones are lipophilic oligopeptides having S-alkylated cysteine at the C-terminus but different amino acid sequences. Synthetic analogues of these pheromones revealed the structure-activity relationships. Metabolism of rhodotorucine A was also studied by using labeled pheromones.

  8. Serotype Distribution and Antimicrobial Susceptibilities of Invasive Streptococcus pneumoniae Isolates from Adults in Korea from 1997 to 2012.

    PubMed

    Kim, Chung Jong; Song, Jin-Su; Choi, Su-Jin; Song, Kyoung Ho; Choe, Pyeong Gyun; Park, Wan Beom; Bang, Ji Hwan; Kim, Eu Suk; Park, Sang Won; Kim, Hong Bin; Kim, Nam-Joong; Kim, Eui-Chong; Oh, Myoung-don

    2016-05-01

    In Republic of Korea, a 7-valent pneumococcal conjugated vaccine (PCV7) was licensed for use in infants in 2003, and 13-valent PCV (PCV13) replaced it since 2010. We investigated trends in serotype distribution and antibiotic susceptibility of pneumococcal isolates from adult patients with invasive pneumococcal diseases (IPD). Invasive pneumococcal isolates from adult patients of ≥ 16 years of age were collected from 1997 to 2012. Serotypes of the isolates were determined by the Quellung reaction. Distribution of serotypes was analyzed according to the vaccine types. Antibiotic susceptibility was tested by using E-test strips. A total of 272 invasive pneumococcal isolates were included. The most common serotypes were serotype 19F (8.5%, 23/272), and serotype 3 (8.1%, 22/272), and 24.6% (67/272) of the isolates were of non-vaccine serotypes. Of the 272 isolates, 2.6% (7/272) were penicillin MICs of ≥ 4 µg/mL. The proportion of the PCV13 serotypes decreased from 63.3% (50/79) in 1997-2003 to 48.6% (17/35) in 2011-2012, whereas that of non-vaccine serotypes was 26.6% (21/79) and 25.7% (9/35), respectively, for the same periods. The proportion of the PCV13 serotypes showed a decreasing trend among adult patients with IPD over the study period.

  9. Clonal Association between Streptococcus pneumoniae Serotype 23A, Circulating within the United States, and an Internationally Dispersed Clone of Serotype 23F

    PubMed Central

    Pai, Rekha; Gertz, Robert E.; Whitney, Cynthia G.; Beall, Bernard

    2005-01-01

    Streptococcus pneumoniae is an important pathogen in the United States and is associated with significant morbidity and mortality. Since the introduction of the seven-valent conjugate vaccine, a significant decline in pneumococcal disease has been reported. However, surveillance for pneumococcal disease remains essential, as the extent of cross protection against vaccine-related serotypes is still unclear. Further, any increase in non-vaccine-related serotypes also needs monitoring. We report on a new clonal association between a vaccine-related serotype, serotype 23A, obtained as part of the Active Bacterial Core surveillance, with an established internationally dispersed Pneumococcal Molecular Epidemiology Network (PMEN) clone, clone Colombia23F-26. Sixty-two isolates of serotype 23A collected from sterile sites during a 2-year period (2002 and 2003) were characterized. Twenty-one (34%) isolates were penicillin nonsusceptible, although none were fully resistant. Pulsed-field gel electrophoresis and multilocus sequence typing analysis showed that 24 (39%) of the serotype 23A isolates shared either genetic identity or high genetic relatedness with PMEN clone Colombia23F-26. Extensive variability was noted within the sequenced region of pbp2b in two penicillin-nonsusceptible isolates as well as in PMEN clone Colombia23F-26, suggesting that these isolates probably acquired penicillin resistance independently. The emergence of such new serotype and genotype associations highlights the dynamic nature of the pneumococcal population, necessitating continuous monitoring in the post-vaccine era. PMID:16272467

  10. Population genetics of Haemophilus influenzae serotype a in three Canadian provinces.

    PubMed

    Tsang, Raymond S W; Shuel, Michelle; Wylie, John; Lefebvre, Brigitte; Hoang, Linda; Law, Dennis K S

    2013-05-01

    Haemophilus influenzae serotype a (Hia) is an important pathogen since the introduction of vaccines for control of disease due to serotype b strains. Using a sodC-based polymerase chain reaction, Hia can be divided into 2 phylogenetic divisions, each with their own unique multilocus sequence types. Most Canadian Hia belongs to clonal division I and the ST-23 clonal complex. The recently described hypervirulent clone of ST-4 was found in a single Canadian isolate. Therefore, surveillance of invasive H. influenzae disease should include serotyping to detect Hia and multilocus sequence typing to detect hypervirulent clones.

  11. Contribution of the Type VI Secretion System Encoded in SPI-19 to Chicken Colonization by Salmonella enterica Serotypes Gallinarum and Enteritidis

    PubMed Central

    Blondel, Carlos J.; Yang, Hee-Jeong; Castro, Benjamín; Chiang, Sebastián; Toro, Cecilia S.; Zaldívar, Mercedes; Contreras, Inés; Andrews-Polymenis, Helene L.; Santiviago, Carlos A.

    2010-01-01

    Salmonella Gallinarum is a pathogen with a host range specific to poultry, while Salmonella Enteritidis is a broad host range pathogen that colonizes poultry sub-clinically but is a leading cause of gastrointestinal salmonellosis in humans and many other species. Despite recent advances in our understanding of the complex interplay between Salmonella and their hosts, the molecular basis of host range restriction and unique pathobiology of Gallinarum remain largely unknown. Type VI Secretion System (T6SS) represents a new paradigm of protein secretion that is critical for the pathogenesis of many Gram-negative bacteria. We recently identified a putative T6SS in the Salmonella Pathogenicity Island 19 (SPI-19) of Gallinarum. In Enteritidis, SPI-19 is a degenerate element that has lost most of the T6SS functions encoded in the island. In this work, we studied the contribution of SPI-19 to the colonization of Salmonella Gallinarum strain 287/91 in chickens. Non-polar deletion mutants of SPI-19 and the clpV gene, an essential T6SS component, colonized the ileum, ceca, liver and spleen of White Leghorn chicks poorly compared to the wild-type strain after oral inoculation. Return of SPI-19 to the ΔSPI-19 mutant, using VEX-Capture, complemented this colonization defect. In contrast, transfer of SPI-19 from Gallinarum to Enteritidis resulted in transient increase in the colonization of the ileum, liver and spleen at day 1 post-infection, but at days 3 and 5 post-infection a strong colonization defect of the gut and internal organs of the experimentally infected chickens was observed. Our data indicate that SPI-19 and the T6SS encoded in this region contribute to the colonization of the gastrointestinal tract and internal organs of chickens by Salmonella Gallinarum and suggest that degradation of SPI-19 T6SS in Salmonella Enteritidis conferred an advantage in colonization of the avian host. PMID:20661437

  12. Mate Choice Drives Evolutionary Stability in a Hybrid Complex

    PubMed Central

    Morgado-Santos, Miguel; Pereira, Henrique Miguel

    2015-01-01

    Previous studies have shown that assortative mating acts as a driver of speciation by countering hybridization between two populations of the same species (pre-zygotic isolation) or through mate choice among the hybrids (hybrid speciation). In both speciation types, assortative mating promotes speciation over a transient hybridization stage. We studied mate choice in a hybrid vertebrate complex, the allopolyploid fish Squalius alburnoides. This complex is composed by several genomotypes connected by an intricate reproductive dynamics. We developed a model that predicts the hybrid complex can persist when females exhibit particular mate choice patterns. Our model is able to reproduce the diversity of population dynamic outcomes found in nature, namely the dominance of the triploids and the dominance of the tetraploids, depending on female mate choice patterns and frequency of the parental species. Experimental mate choice trials showed that females exhibit the preferences predicted by the model. Thus, despite the known role of assortative mating in driving speciation, our findings suggest that certain mate choice patterns can instead hinder speciation and support the persistence of hybrids over time without speciation or extinction. PMID:26181664

  13. In Vivo and In Vitro Anaerobic Mating in Candida albicans▿

    PubMed Central

    Dumitru, Raluca; Navarathna, Dhammika H. M. L. P.; Semighini, Camile P.; Elowsky, Christian G.; Dumitru, Razvan V.; Dignard, Daniel; Whiteway, Malcolm; Atkin, Audrey L.; Nickerson, Kenneth W.

    2007-01-01

    Candida albicans cells of opposite mating types are thought to conjugate during infection in mammalian hosts, but paradoxically, the mating-competent opaque state is not stable at mammalian body temperatures. We found that anaerobic conditions stabilize the opaque state at 37°C, block production of farnesol, and permit in vitro mating at 37°C at efficiencies of up to 84%. Aerobically, farnesol prevents mating because it kills the opaque cells necessary for mating, and as a corollary, farnesol production is turned off in opaque cells. These in vitro observations suggest that naturally anaerobic sites, such as the efficiently colonized gastrointestinal (GI) tract, could serve as niches for C. albicans mating. In a direct test of mating in the mouse GI tract, prototrophic cells were obtained from auxotrophic parent cells, confirming that mating will occur in this organ. These cells were true mating products because they were tetraploid, mononuclear, and prototrophic, and they contained the heterologous hisG marker from one of the parental strains. PMID:17259544

  14. Mating of Phytophthora ramorum: functionality and consequences

    Treesearch

    Xavier Boutet; Annelies Vercauteren; Chandelier Heungens; Anne Kurt

    2010-01-01

    Phytophthora ramorum (Werres, De Cock, Man in’t Veld), which causes “sudden oak death” in the United States and dieback and leaf necrosis in ornamental plants (mainly Rhododendron and Viburnum) in Europe, is a heterothallic species with two mating types, A1 and A2 (Werres and others 2001, Rizzo and...

  15. The dermatophyte species Arthroderma benhamiae: intraspecies variability and mating behaviour.

    PubMed

    Symoens, Françoise; Jousson, Olivier; Packeu, Ann; Fratti, Marina; Staib, Peter; Mignon, Bernard; Monod, Michel

    2013-03-01

    Arthroderma benhamiae is a zoophilic dermatophyte belonging to the Trichophyton mentagrophytes species complex. Here, a population of A. benhamiae wild strains from the same geographical area (Switzerland) was studied by comparing their morphology, assessing their molecular variability using internal transcribed spacer (ITS) and 28S rRNA gene sequencing, and evaluating their interfertility. Sequencing of the ITS region and of part of the 28S rRNA gene revealed the existence of two infraspecific groups with markedly different colony phenotypes: white (group I) and yellow (group II), respectively. For all strains, the results of mating type identification by PCR, using HMG (high-mobility group) and α-box genes in the mating type locus as targets, were in total accordance with the results of mating type identification by strain confrontation experiments. White-phenotype strains were of mating type + (mt+) or mating type - (mt-), whilst yellow-phenotype strains were all mt-. White and yellow strains were found to produce fertile cleistothecia after mating with A. benhamiae reference tester strains, which belonged to a third group intermediate between groups I and II. However, no interfertility was observed between yellow strains and white strains of mt+. A significant result was that white strains of mt- were able to mate and produce fertile cleistothecia with the white A. benhamiae strain CBS 112371 (mt+), the genome of which has recently been sequenced and annotated. This finding should offer new tools for investigating the biology and genetics of dermatophytes using wild-type strains.

  16. Serotyping of Pasteurella multocida isolated from swine lungs collected at slaughter.

    PubMed Central

    Pijoan, C; Morrison, R B; Hilley, H D

    1983-01-01

    We serotyped 222 Pasteurella multocida strains isolated from swine lungs at slaughter. Capsular serotypes A and D were determined by the hyaluronidase sensitivity and acriflavin agglutination tests, respectively. Somatic antigens were determined by gel diffusion against standard antisera. Capsular serotype A was found in 97.3% of the strains and serotype D in the remaining 2.7%. The primary somatic antigen most commonly found was type 3 (86.0%). Type 5 was also very common (88.7%), but was usually a secondary antigen. The most common overall serotype was A:3(5) (39.2%). Other common serotypes were: A:3(4,5,12) (12.2%); A:3(4,5) (11.2%); A:3(5,12) (10.4%); A:3 (6.8%); and A:5 (6.8%). Type D strains had a similar distribution of serotypes, but with a higher prevalence of D:5 (33.3%) and D:3(5) (33.3%). PMID:6874900

  17. Molecular Epidemiology and Distribution of Serotypes, Surface Proteins, and Antibiotic Resistance among Group B Streptococci in Italy▿

    PubMed Central

    Gherardi, Giovanni; Imperi, Monica; Baldassarri, Lucilla; Pataracchia, Marco; Alfarone, Giovanna; Recchia, Simona; Orefici, Graziella; Dicuonzo, Giordano; Creti, Roberta

    2007-01-01

    Group B streptococci (GBS) comprising three different sets of isolates (31 invasive, 36 noninvasive, and 24 colonizing isolates) were collected in Italy during the years 2002 to 2005. Clonal groups were established by pulsed-field gel electrophoresis (PFGE), and selected isolates were studied by multilocus sequence typing (MLST). GBS isolates were also characterized by classical and molecular techniques for serotyping and protein gene and antibiotic resistance profiling. Some serotypes were significantly associated with a particular isolate population: serotype Ia more frequently corresponded to invasive strains than other strains, serotype V was more frequently encountered among noninvasive strains, and nontypeable strains were more common among isolates from carriers. Four major clonal groups accounted for 52.7% of all isolates: PFGE type 1/clonal complex 1 (CC1) comprised mainly serotype V isolates carrying the alp3 gene, PFGE type 2/CC23 encompassed serotype Ia isolates with the alp1 or alpha gene, PFGE type 3/CC17 comprised serotype III isolates carrying the rib gene, and PFGE type 4/CC19 consisted mainly of serotype II isolates possessing the rib gene. The same serotypes were shared by isolates of different clonal groups, and conversely, isolates belonging to the same clonal groups were found to be of different serotypes, presumably due to capsular switching by the horizontal transfer of capsular genes. Erythromycin resistance (prevalence, 16.5%; 15 resistant isolates of 91) was restricted to strains isolated from patients with noninvasive infections and carriers, while tetracycline resistance was evenly distributed (prevalence, 68.1%; 62 resistant isolates of 91). Most erythromycin-resistant GBS strains were of serotype V, were erm(B) positive, and belonged to the PFGE type 1/CC1 group, suggesting that macrolide resistance may have arisen both by clonal dissemination and by the horizontal transfer of resistance genes. PMID:17634303

  18. Discrepancy between Penner serotyping and polymerase chain reaction fingerprinting of Campylobacter isolated from poultry and other animal sources.

    PubMed

    Aarts, H J; van Lith, L A; Jacobs-Reitsma, W F

    1995-06-01

    Thirty-four Campylobacter jejuni or coli strains, isolated from various livestock and darkling beetles from two Dutch poultry farms during different broiler production cycles, were subjected to Penner serotyping and polymerase chain reaction (PCR) fingerprint analysis. Ten different Penner serotypes were determined in the isolates. Visual scoring of the PCR fingerprints resulted in 14 clearly different profiles. Some strains with identical Penner serotypes exhibited different PCR fingerprints and conversely strains with different serotypes produced identical PCR fingerprints. Discrepancies between Penner serotyping and PCR fingerprinting were most obvious between isolates from different animal sources. Indications for the occurrence of genomic rearrangements were found. The inconsistency between serotyping and fingerprinting of Campylobacter strains suggests that conventional typing methods should be used in combination with fingerprinting if the epidemiological factors that contribute to Campylobacter colonization of live chickens are to be assessed reliably.

  19. Structures and sugar compositions of lipopolysaccharides isolated from seven Actinobacillus pleuropneumoniae serotypes.

    PubMed Central

    Byrd, W; Kadis, S

    1989-01-01

    Highly purified lipopolysaccharide (LPS) preparations obtained from seven Actinobacillus pleuropneumoniae strains representative of seven different serotypes were used to determine the structure and monosaccharide composition of the polysaccharide components of each lipopolysaccharide. An indication of the structure of each LPS was obtained by procedures that included sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining and gel chromatographic fractionation of acetic acid-hydrolyzed LPS. The polysaccharide components of the LPSs were analyzed by gas-liquid chromatography. The LPSs of the strains of serotypes 2, 4, and 7 were of the smooth type, and those of the strains of serotypes 3 and 6 were of the rough type; the LPSs of the strains of serotypes 1 and 5 could be considered semirough. Rhamnose was present only in the O polysaccharide of the smooth-type and semirough-type LPSs, whereas galactose was present only in the O polysaccharide of the smooth-type LPS and in the core oligosaccharides of the rough-type and semirough-type LPSs. Glucoheptose and mannoheptose were present in the core oligosaccharides of all the LPSs except for the strain of serotype 3, in which only mannoheptose was detected. N-Acetylglucosamine was detected only in the O polysaccharides of the strains of serotypes 1 and 5. Images PMID:2807553

  20. Influences on assortative mating.

    PubMed

    Schmidt, H D; Glavce, C; Hartog, J

    1987-09-01

    Age plays a considerable role in assortative mating. As regards this criterion we can distinguish a "rural, more traditional model" with high values of the coefficients of correlation, and an "urban model" with significantly lower values. Concerning eye and hair colour we find both these models as well as transitional forms. In contrast to this there are no important differences in assortative mating between the rural and urban populations regarding the physical traits. Size of population and length of marriage can strongly influence the values of these correlations. They decrease as the size of the population decreases, in which a person chooses his/her partner. Increasing age of the couples also results in a decrease of these correlations.

  1. The a2 mating-type locus genes lga2 and rga2 direct uniparental mitochondrial DNA (mtDNA) inheritance and constrain mtDNA recombination during sexual development of Ustilago maydis.

    PubMed

    Fedler, Michael; Luh, Kai-Stephen; Stelter, Kathrin; Nieto-Jacobo, Fernanda; Basse, Christoph W

    2009-03-01

    Uniparental inheritance of mitochondria dominates among sexual eukaryotes. However, little is known about the mechanisms and genetic determinants. We have investigated the role of the plant pathogen Ustilago maydis genes lga2 and rga2 in uniparental mitochondrial DNA (mtDNA) inheritance during sexual development. The lga2 and rga2 genes are specific to the a2 mating-type locus and encode small mitochondrial proteins. On the basis of identified sequence polymorphisms due to variable intron numbers in mitochondrial genotypes, we could demonstrate that lga2 and rga2 decisively influence mtDNA inheritance in matings between a1 and a2 strains. Deletion of lga2 favored biparental inheritance and generation of recombinant mtDNA molecules in combinations in which inheritance of mtDNA of the a2 partner dominated. Conversely, deletion of rga2 resulted in predominant loss of a2-specific mtDNA and favored inheritance of the a1 mtDNA. Furthermore, expression of rga2 in the a1 partner protected the associated mtDNA from elimination. Our results indicate that Lga2 in conjunction with Rga2 directs uniparental mtDNA inheritance by mediating loss of the a1-associated mtDNA. This study shows for the first time an interplay of mitochondrial proteins in regulating uniparental mtDNA inheritance.

  2. The a2 Mating-Type Locus Genes lga2 and rga2 Direct Uniparental Mitochondrial DNA (mtDNA) Inheritance and Constrain mtDNA Recombination During Sexual Development of Ustilago maydis

    PubMed Central

    Fedler, Michael; Luh, Kai-Stephen; Stelter, Kathrin; Nieto-Jacobo, Fernanda; Basse, Christoph W.

    2009-01-01

    Uniparental inheritance of mitochondria dominates among sexual eukaryotes. However, little is known about the mechanisms and genetic determinants. We have investigated the role of the plant pathogen Ustilago maydis genes lga2 and rga2 in uniparental mitochondrial DNA (mtDNA) inheritance during sexual development. The lga2 and rga2 genes are specific to the a2 mating-type locus and encode small mitochondrial proteins. On the basis of identified sequence polymorphisms due to variable intron numbers in mitochondrial genotypes, we could demonstrate that lga2 and rga2 decisively influence mtDNA inheritance in matings between a1 and a2 strains. Deletion of lga2 favored biparental inheritance and generation of recombinant mtDNA molecules in combinations in which inheritance of mtDNA of the a2 partner dominated. Conversely, deletion of rga2 resulted in predominant loss of a2-specific mtDNA and favored inheritance of the a1 mtDNA. Furthermore, expression of rga2 in the a1 partner protected the associated mtDNA from elimination. Our results indicate that Lga2 in conjunction with Rga2 directs uniparental mtDNA inheritance by mediating loss of the a1-associated mtDNA. This study shows for the first time an interplay of mitochondrial proteins in regulating uniparental mtDNA inheritance. PMID:19104076

  3. Prevalence and Characteristics of Salmonella Serotypes Isolated from Fresh Produce Marketed in the United States.

    PubMed

    Reddy, Shanker P; Wang, Hua; Adams, Jennifer K; Feng, Peter C H

    2016-01-01

    Salmonella continues to rank as one of the most costly foodborne pathogens, and more illnesses are now associated with the consumption of fresh produce. The U.S. Department of Agriculture Microbiological Data Program (MDP) sampled select commodities of fresh fruit and vegetables and tested them for Salmonella, pathogenic Escherichia coli, and Listeria. The Salmonella strains isolated were further characterized by serotype, antimicrobial resistance, and pulsed-field gel electrophoresis profile. This article summarizes the Salmonella data collected by the MDP between 2002 and 2012. The results show that the rates of Salmonella prevalence ranged from absent to 0.34% in cilantro. A total of 152 isolates consisting of over 50 different serotypes were isolated from the various produce types, and the top five were Salmonella enterica serotype Cubana, S. enterica subspecies arizonae (subsp. IIIa) and diarizonae (subsp. IIIb), and S. enterica serotypes Newport, Javiana, and Infantis. Among these, Salmonella serotypes Newport and Javiana are also listed among the top five Salmonella serotypes that caused most foodborne outbreaks. Other serotypes that are frequent causes of infection, such as S. enterica serotypes Typhimurium and Enteritidis, were also found in fresh produce but were not prevalent. About 25% of the MDP samples were imported produce, including 65% of green onions, 44% of tomatoes, 42% of hot peppers, and 41% of cantaloupes. However, imported produce did not show higher numbers of Salmonella-positive samples, and in some products, like cilantro, all of the Salmonella isolates were from domestic samples. About 6.5% of the Salmonella isolates were resistant to the antimicrobial compounds tested, but no single commodity or serotype was found to be the most common carrier of resistant strains or of resistance. The pulsed-field gel electrophoresis profiles of the produce isolates showed similarities with Salmonella isolates from meat samples and from outbreaks, but

  4. Distribution and annual changes in Streptococcus pneumoniae serotypes in adult Japanese patients with pneumonia.

    PubMed

    Akata, Kentaro; Chang, Bin; Yatera, Kazuhiro; Kawanami, Toshinori; Yamasaki, Kei; Naito, Keisuke; Noguchi, Shingo; Ishimoto, Hiroshi; Mukae, Hiroshi

    2015-10-01

    Streptococcus pneumoniae is one of the main causative bacteria in patients with pneumonia; however, there are no data regarding serotype changes in adult patients with pneumonia after the introduction of the pneumococcal vaccine (PCV7) for childhood immunization in Japan. We herein evaluated the serotype distribution in adult patients with pneumonia. This retrospective epidemiological study was performed at the University of Occupational and Environmental Health, Japan from January 2011 to December 2013. The serotypes of pneumococcal isolates obtained from patients with pneumonia were evaluated along with the patients' clinical information. A total of 81 patients with pneumococcal pneumonia (89 episodes) from whom S. pneumoniae was isolated were included. The numbers (percentages) of sample types were as follows: sputum 55 (61.8%), intratracheal tube suction 15 (16.9%), intrabronchial sampling 5 (5.6%) and bronchoalveolar lavage fluid 14 (15.7%). The PCV7 serotypes decreased significantly among the patients with pneumococcal pneumonia from 46.4% in 2011 to 20.0% in 2013 (p < 0.05). Conversely, PCV13 and 23-valent pneumococcal polysaccharide vaccination (PPSV23) serotypes other than PCV7 serotypes mildly increased during this period. In addition, the frequency of serotypes 19F, 23F and 4 (which are covered by PCV7) decreased annually; however, the changes in the frequencies of the other serotypes were not significant. This study demonstrated the yearly decrease of PCV7 serotypes in adult pneumococcal pneumonia patients after introducing PCV7 into the childhood immunization schedule in Japan. Continued surveillance of pneumococcal serotype changes is important for the proper use of different pneumococcal vaccines. Copyright © 2015 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  5. Genetic and virulence-phenotype characterization of serotypes 2 and 9 of Streptococcus suis swine isolates.

    PubMed

    Blume, Verena; Luque, Inmaculada; Vela, Ana I; Borge, Carmen; Maldonado, Alfonso; Domínguez, Lucas; Tarradas, Carmen; Fernández-Garayzábal, José F

    2009-09-01

    The aim of this study was to analyze the genetic characteristics and virulence phenotypes of Streptococcus suis, specifically, in clinical isolates of serotypes 2 and 9 (n = 195), obtained from diverse geographical areas across Spain. Pulsed-field gel electrophoresis (PFGE) typing identified 97 genetic profiles, 68% of which were represented by single isolates, indicative of a substantial genetic diversity among the S. suis isolates analyzed. Five PFGE profiles accounted for 33.3% of the isolates and were isolated from 38% of the herds in nine different provinces, indicative of the bacterium's widespread distribution in the Spanish swine population. Representative isolates of the most prevalent PFGE profiles of both serotypes were subjected to multilocus sequence typing (MLST) analysis. The results indicated that serotypes 2 and 9 have distinct genetic backgrounds. Serotype 2 isolates belong to the ST1 complex, a highly successful clone that has spread over most European countries. In accordance with isolates of this complex, most serotype 2 isolates also expressed the phenotype MRP(+)EF(+)SLY(+). Serotype 9 isolates belong to the ST61 complex, which is distantly related to the widespread European ST87 clone. Also, in contrast to most isolates of the European ST87 clone, which express the large variant MRP*, the majority of serotype 9 isolates (97.9%) did not express the protein.

  6. Clonal dissemination of human isolates of Streptococcus suis serotype 14 in Thailand.

    PubMed

    Kerdsin, Anusak; Oishi, Kazunori; Sripakdee, Saowalak; Boonkerd, Nitsara; Polwichai, Pitimol; Nakamura, Shota; Uchida, Ryuichi; Sawanpanyalert, Pathom; Dejsirilert, Surang

    2009-11-01

    Most cases of Streptococcus suis infection in humans are caused by serotype 2 strains, and only a few cases caused by other serotypes have been reported. Among 177 human isolates of S. suis in Thailand, 12 (6.8 %) were identified as being of serotype 14, and an occurrence of sporadic S. suis serotype 14 infection was noted during 2006-2008, particularly in northern Thailand. Clinical presentations of the 12 patients (median age 62.9 years) included meningitis (58.3 %), septic arthritis (25 %) and sepsis (16.7 %). These clinical features were similar to those previously reported for S. suis infections, except that there were no fatal cases. All of the 12 serotype 14 strains belonged to the multilocus sequence types (ST) 105 (n=11) and the novel ST127 (n=1). Molecular typing by PFGE revealed four different pulsotypes, including an identical pattern for nine ST105 strains and three closely related patterns for two ST105 strains and one ST127 strain. Our PFGE data suggested clonal dissemination of ST105 strains in Thailand. Because serotype 14 is becoming a more common cause of S. suis infections in humans, diagnostic tests for serotype 14 should be performed in South-East Asian countries.

  7. Efficient Breeding by Genomic Mating.

    PubMed

    Akdemir, Deniz; Sánchez, Julio I

    2016-01-01

    Selection in breeding programs can be done by using phenotypes (phenotypic selection), pedigree relationship (breeding value selection) or molecular markers (marker assisted selection or genomic selection). All these methods are based on truncation selection, focusing on the best performance of parents before mating. In this article we proposed an approach to breeding, named genomic mating, which focuses on mating instead of truncation selection. Genomic mating uses information in a similar fashion to genomic selection but includes information on complementation of parents to be mated. Following the efficiency frontier surface, genomic mating uses concepts of estimated breeding values, risk (usefulness) and coefficient of ancestry to optimize mating between parents. We used a genetic algorithm to find solutions to this optimization problem and the results from our simulations comparing genomic selection, phenotypic selection and the mating approach indicate that current approach for breeding complex traits is more favorable than phenotypic and genomic selection. Genomic mating is similar to genomic selection in terms of estimating marker effects, but in genomic mating the genetic information and the estimated marker effects are used to decide which genotypes should be crossed to obtain the next breeding population.

  8. Efficient Breeding by Genomic Mating

    PubMed Central

    Akdemir, Deniz; Sánchez, Julio I.

    2016-01-01

    Selection in breeding programs can be done by using phenotypes (phenotypic selection), pedigree relationship (breeding value selection) or molecular markers (marker assisted selection or genomic selection). All these methods are based on truncation selection, focusing on the best performance of parents before mating. In this article we proposed an approach to breeding, named genomic mating, which focuses on mating instead of truncation selection. Genomic mating uses information in a similar fashion to genomic selection but includes information on complementation of parents to be mated. Following the efficiency frontier surface, genomic mating uses concepts of estimated breeding values, risk (usefulness) and coefficient of ancestry to optimize mating between parents. We used a genetic algorithm to find solutions to this optimization problem and the results from our simulations comparing genomic selection, phenotypic selection and the mating approach indicate that current approach for breeding complex traits is more favorable than phenotypic and genomic selection. Genomic mating is similar to genomic selection in terms of estimating marker effects, but in genomic mating the genetic information and the estimated marker effects are used to decide which genotypes should be crossed to obtain the next breeding population. PMID:27965707

  9. Mechanical seal having a double-tier mating ring

    DOEpatents

    Khonsari, Michael M.; Somanchi, Anoop K.

    2005-09-13

    An apparatus and method to enhance the overall performance of mechanical seals in one of the following ways: by reducing seal face wear, by reducing the contact surface temperature, or by increasing the life span of mechanical seals. The apparatus is a mechanical seal (e.g., single mechanical seals, double mechanical seals, tandem mechanical seals, bellows, pusher mechanical seals, and all types of rotating and reciprocating machines) comprising a rotating ring and a double-tier mating ring. In a preferred embodiment, the double-tier mating ring comprises a first and a second stationary ring that together form an agitation-inducing, guided flow channel to allow for the removal of heat generated at the seal face of the mating ring by channeling a coolant entering the mating ring to a position adjacent to and in close proximity with the interior surface area of the seal face of the mating ring.

  10. The Relevance of a Novel Quantitative Assay to Detect up to 40 Major Streptococcus pneumoniae Serotypes Directly in Clinical Nasopharyngeal and Blood Specimens

    PubMed Central

    Albrich, Werner C.; van der Linden, Mark P. G.; Bénet, Thomas; Chou, Monidarin; Sylla, Mariam; Barreto Costa, Patricia; Richard, Nathalie; Klugman, Keith P.; Endtz, Hubert P.; Paranhos-Baccalà, Gláucia; Telles, Jean-Noël

    2016-01-01

    For epidemiological and surveillance purposes, it is relevant to monitor the distribution and dynamics of Streptococcus pneumoniae serotypes. Conventional serotyping methods do not provide rapid or quantitative information on serotype loads. Quantitative serotyping may enable prediction of the invasiveness of a specific serotype compared to other serotypes carried. Here, we describe a novel, rapid multiplex real-time PCR assay for identification and quantification of the 40 most prevalent pneumococcal serotypes and the assay impacts in pneumonia specimens from emerging and developing countries. Eleven multiplex PCR to detect 40 serotypes or serogroups were optimized. Quantification was enabled by reference to standard dilutions of known bacterial load. Performance of the assay was evaluated to specifically type and quantify S. pneumoniae in nasopharyngeal and blood samples from adult and pediatric patients hospitalized with pneumonia (n = 664) from five different countries. Serogroup 6 was widely represented in nasopharyngeal specimens from all five cohorts. The most frequent serotypes in the French, South African, and Brazilian cohorts were 1 and 7A/F, 3 and 19F, and 14, respectively. When both samples were available, the serotype in blood was always present as carriage with other serotypes in the nasopharynx. Moreover, the ability of a serotype to invade the bloodstream may be linked to its nasopharyngeal load. The mean nasopharyngeal concentration of the serotypes that moved to the blood was 3 log-fold higher than the ones only found in the nasopharynx. This novel, rapid, quantitative assay may potentially predict some of the S. pneumoniae serotypes invasiveness and assessment of pneumococcal serotype distribution. PMID:26986831

  11. Serotype b of Aggregatibacter actinomycetemcomitans increases osteoclast and memory T-lymphocyte activation.

    PubMed

    Melgar-Rodríguez, S; Díaz-Zúñiga, J; Alvarez, C; Rojas, L; Monasterio, G; Carvajal, P; Escobar, A; Sanz, M; Vernal, R

    2016-04-01

    During periodontitis, alveolar bone resorption is associated with activation of T helper type 17 (Th17) lymphocytes and receptor activator of nuclear factor-κB ligand (RANKL) -induced osteoclasts. We previously reported that serotype b of Aggregatibacter actinomycetemcomitans has a higher capacity to trigger Th17-type differentiation and function in activated T lymphocytes and its lipopolysaccharide is a more potent immunogen compared with the other serotypes. This study aimed to investigate whether serotype b of A. actinomycetemcomitans induces higher Th17-associated RANKL production, RANKL-induced osteoclast activation, and antigen-specific memory T lymphocyte proliferation. On naive CD4(+) T lymphocytes stimulated with autologous dendritic cells primed with different A. actinomycetemcomitans serotypes, RANKL production, T-bet, GATA-3, RORC2 and Foxp3 expression, RORC2/RANKL intracellular double-expression, TRAP(+) osteoclast activation, and bone resorption were quantified. The frequency of proliferating memory T lymphocytes in response to A. actinomycetemcomitans serotypes was determined in periodontitis and healthy subjects. Naive CD4(+) T lymphocytes stimulated by serotype b-primed dendritic cells elicited higher levels of RANKL, RORC2, TRAP(+) osteoclasts, and bone resorption than the same cells stimulated with the other serotypes. RANKL positively correlated and co-expressed with RORC2. Memory T lymphocytes responding to serotype b were more frequently detected in periodontitis patients than healthy subjects. These results indicate that serotype b of A. actinomycetemcomitans is associated with higher production of RANKL and these increased levels are associated with Th17 lymphocyte induction, osteoclast activation, and bone resorption.

  12. Serotype assignment by sero-agglutination, ELISA, and PCR

    USDA-ARS?s Scientific Manuscript database

    For assessing isolates of Listeria monocytogenes serotype designation is the foremost subtyping method used. Traditionally serotyping has been done with agglutination reactions. In the last decade alternative serotyping methods were described using Enzyme Linked Immunosorbent Assay(ELISA)and Polymer...

  13. Biased learning affects mate choice in a butterfly

    PubMed Central

    Westerman, Erica L.; Hodgins-Davis, Andrea; Dinwiddie, April; Monteiro, Antónia

    2012-01-01

    Early acquisition of mate preferences or mate-preference learning is associated with signal diversity and speciation in a wide variety of animal species. However, the diversity of mechanisms of mate-preference learning across taxa remains poorly understood. Using the butterfly Bicyclus anynana we uncover a mechanism that can lead to directional sexual selection via mate-preference learning: a bias in learning enhanced ornamentation, which is independent of preexisting mating biases. Naïve females mated preferentially with wild-type males over males with enhanced wing ornamentation, but females briefly exposed to enhanced males mated significantly more often with enhanced males. In contrast, females exposed to males with reduced wing ornamentation did not learn to prefer drab males. Thus, we observe both a learned change of a preexisting mating bias, and a bias in ability to learn enhanced male ornaments over reduced ornaments. Our findings demonstrate that females are able to change their preferences in response to a single social event, and suggest a role for biased learning in the evolution of visual sexual ornamentation. PMID:22689980

  14. Structure elucidation of capsular polysaccharides from Streptococcus pneumoniae serotype 33C, 33D, and revised structure of serotype 33B.

    PubMed

    Lin, Fiona L; Vinogradov, Evgeny; Deng, Chenghua; Zeller, Sandra; Phelan, Lynn; Green, Bruce A; Jansen, Kathrin U; Pavliak, Viliam

    2014-01-13

    We report herein the previously unknown structures of the pneumococcal capsular polysaccharides serotype 33C and 33D, and a revised structure of serotype 33B. The syntenic pair 33B/33D has nearly identical polysaccharide repeat units with the exception of one sugar residue (→2-α-Glcp in 33B and →2-α-Galp in 33D). Serotype 33C is structurally more similar to 33B/33D than 33A/33F, in that it also possesses a backbone ribitol-phosphate group and a →3-β-GalpNAc residue, both of which are absent in the repeat units of 33A/33F. Serotype 33C is notably different from all other serogroup 33 polysaccharides, as there is no →3-β-Glcp residue and the location of the O-acetylation of the →5-β-Galf residue (O-6) differs from the other serogroup 33 polysaccharides (O-2). This completes the structural assignments of polysaccharides within serogroup 33 and provides a framework for understanding the recognition of epitopes by serogroup 33 typing sera based on observed cross-reactivities reported in the literature. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Invasive pneumococcal disease caused by mucoid serotype 3 Streptococcus pneumoniae: a case report and literature review.

    PubMed

    Sugimoto, Naomi; Yamagishi, Yuka; Hirai, Jun; Sakanashi, Daisuke; Suematsu, Hiroyuki; Nishiyama, Naoya; Koizumi, Yusuke; Mikamo, Hiroshige

    2017-01-04

    Among the different serotypes of Streptococcus pneumoniae, serotype 3 has received global attention. We report the fatal case of a 76-year-old Japanese man who had an invasive pneumococcal disease associated with pneumonia caused by serotype 3 S. pneumoniae. The patient had a history of hypertension, laryngeal cancer, chronic obstructive pulmonary disease, and type 2 diabetes mellitus. Following a cerebral arteriovenous malformation hemorrhage, he underwent surgery to remove the hematoma and began rehabilitation. On day 66 of hospitalization, he suddenly developed a fever, and coarse crackles and wheezes were heard in his right lung. A diagnosis of hospital-acquired aspiration pneumonia was made, and initial treatment with piperacillin/tazobactam was started. Teicoplanin was added after S. pneumoniae was isolated from the blood culture, however, the patient died 5 days later. The S. pneumoniae detected in the sputum smear was serotype 3, showed mucoid colonies and susceptibility to penicillins, cephalosporins, carbapenems, and levofloxacin, but resistance to erythromycin. We experienced a fatal case of pneumonia caused by mucoid serotype 3 S. pneumoniae with a thick capsule. Serotype 3-associated pneumonia may develop a wider pulmonary infiltrative shadow, a prolonged therapeutic or hospitalization course, and a poor outcome. Careful observation and intervention are required, and the use of additional antibiotics or intravenous immunoglobulins should be considered in such cases. Pneumococcal immunization is also an important public health measure to minimize the development of severe infections caused by serotype 3 strains.

  16. Correlation of Serotypes and Genotypes of Macrolide-Resistant Streptococcus agalactiae

    PubMed Central

    Kim, Hyo Youl; Jang, In Ho; Hwang, Gyu Yel; Yoon, Kap Jun

    2005-01-01

    Despite the necessity for studies of group B streptococci (GBS), due to the increase in serious adult infections, the emergence of new serotypes, and the increased resistance to macrolide antibiotics, such studies have been limited in Korea. The primary purpose of the present study was to determine the frequency trends of GBS serotypes, including serotypes VI, VII, and VIII. The final objective was to elucidate the relationship between the genotypes and serotypes of macrolide-resistant GBS isolates from a Korean population. Among 446 isolates of Streptococcus agalactiae, isolated between January 1990 and December 2002 in Korea, the frequency of serotypes were III (36.5%), Ib (22.0%), V (21.1%), Ia (9.6%), VI (4.3%), II (1.8%), VIII (1.3%), IV (1.1%), and VII (0.9%). The resistance rates to erythromycin, by serotype, were 85% (V), 23% (III), 21% (VI), 3% (Ib), and 2% (Ia). Of 135 erythromycin-resistant S. agalactiae, ermB was detected in 105 isolates, mefA in 20 isolates, and ermTR in seven isolates; most type V isolates harbored the ermB gene, Ib type isolates had an equal distribution of resistance genes, type III isolates accounted for 70% of all isolates carrying mefA genes, and one fourth of type VI isolates had mefA genes. PMID:16127771

  17. Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera).

    PubMed

    Snell, Terry W; Shearer, Tonya L; Smith, Hilary A; Kubanek, Julia; Gribble, Kristin E; Welch, David B Mark

    2009-09-09

    Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s). We describe the isolation and characterization of the mate recognition pheromone gene through protein purification, N-terminal amino acid sequence determination, identification of the mate recognition pheromone gene from a cDNA library, sequencing, and RNAi knockdown to confirm the functional role of the mate recognition pheromone gene in rotifer mating. A 29 kD protein capable of eliciting rotifer male circling was isolated by high-performance liquid chromatography. Two transcript types containing the N-terminal sequence were identified in a cDNA library; further characterization by screening a genomic library and by polymerase chain reaction revealed two genes belonging to each type. Each gene begins with a signal peptide region followed by nearly perfect repeats of an 87 to 92 codon motif with no codons between repeats and the final motif prematurely terminated by the stop codon. The two Type A genes contain four and seven repeats and the two Type B genes contain three and five repeats, respectively. Only the Type B gene with three repeats encodes a peptide with a molecular weight of 29 kD. Each repeat of the Type B gene products contains three asparagines as potential sites for N-glycosylation; there are no asparagines in the Type A genes. RNAi with Type A double-stranded RNA did not result in less circling than in the phosphate-buffered saline control, but transfection with Type B double-stranded RNA significantly reduced male circling by 17%. The very low divergence between repeat units, even at synonymous positions, suggests that the

  18. Truncated surface protective antigen (SpaA) of Erysipelothrix rhusiopathiae serotype 1a elicits protection against challenge with serotypes 1a and 2b in pigs.

    PubMed

    Imada, Y; Goji, N; Ishikawa, H; Kishima, M; Sekizaki, T

    1999-09-01

    Erysipelothrix rhusiopathiae is a causal agent of swine erysipelas, which is of economic importance in the swine industry by virtue of causing acute septicemia, chronic arthritis, and endocarditis. However, little is known about the genetic properties of its protective antigens. Recently, a surface protective antigen (SpaA) gene was identified from serotype 2 in a mouse model. We cloned spaA from virulent strain Fujisawa (serotype 1a) and determined that the N-terminal 342 amino acids without C-terminal repeats of 20 amino acids have the ability to elicit protection in mice. Fusions of 342 amino acids of Fujisawa SpaA and histidine hexamer (HisSpa1.0) protected pigs against challenge with both serotype 1 and serotype 2, the most important serotypes in the swine industry. Pigs immunized with HisSpa1.0 reacted well with both HisSpa1.0 and intact SpaA by enzyme-linked immunosorbent assay and immunoblotting. Serum collected at the time of challenge from a pig immunized with HisSpa1. 0 markedly enhanced the in vitro phagocytic and killing activity of pig neutrophils against the bacteria. DNA sequences of protective regions of spaA genes from five strains of serotypes 1 and 2 were almost identical. The full DNA sequences also seemed to be conserved among strains of all 12 serotype reference strains harboring the spaA gene by restriction fragment length polymorphism analysis of PCR products. These results indicates that SpaA is a common protective antigen of serotypes 1 and 2 of E. rhusiopathiae in swine and will be a useful tool for development of new types of vaccines and diagnostic tools for effective control of the disease.

  19. Variation in mating systems of salamanders: mate guarding or territoriality?

    PubMed

    Deitloff, Jennifer; Alcorn, Michael A; Graham, Sean P

    2014-07-01

    Two of the most common mating tactics in vertebrates are mate guarding and territoriality, yet much of the research on these strategies has focused on mating systems in birds, despite novel insights gained from studying less traditional systems. North American stream salamanders that comprise the Eurycea bislineata complex represent an excellent nontraditional system for comparing mating strategies because these species exhibit a continuum of male morphologies, diverse habitat associations, and various potential mating strategies. We studied two species within this complex that exhibit the extremes of this continuum, Eurycea aquatica (robust morph) and Eurycea cirrigera (slender morph). The larger head in males of E. aquatica is due to larger musculature around the jaw and may be associated with aggressive behavior. Therefore, we hypothesized that the robust morphology exhibited by males of E. aquatica provides benefits during either territorial defense or mate defense and that males of E. cirrigera would not exhibit aggression in either scenario. We found that neither species exhibited aggressive behavior to defend a territory. However, in the presence of a female, males of E. aquatica were significantly more aggressive toward intruding males than were males of E. cirrigera. Therefore, mate-guarding behavior occurs in E. aquatica, and the enlarged head of males likely aids in deterring rivals. This is the first demonstration of mate-guarding behavior in a plethodontid, the most speciose family of salamanders.

  20. Are mating strategies and mating tactics independent constructs?

    PubMed

    Allen, J Sabura; Bailey, Kent G

    2007-08-01

    This study explored the constructs of mating tactics and mating strategy. These constructs are conceptually related but distinct. In current research, the measurement of one of these constructs is often viewed as being indicative of the other. Therefore, an exploration of these constructs will enhance understanding of study outcomes in this research area. Self-report measures of mating tactics and strategies were administered to 183 female participants, aged 18-45 years. The Escalating Sexual Encounters Questionnaire (ESEQ, Greer & Buss, 1994), the Derogatis' Sexual Experience Scale (Derogatis & Melisaratos, 1979), the Sexual Strategies Measure (SSM, Schmitt, 1996), the Sociosexual Orientation Inventory (Simpson & Gangestad, 1991), and two questions assessing age at menarche and total number of sexual partners were administered. Exploratory factor analysis with oblique rotation produced two distinct factors reflecting a "tactic"-based factor and a "strategy"-based factor. This finding is consistent with viewing mating tactics and mating strategies as distinct and varying independently. An important implication of this study is that measurement of mating tactics is not indicative of underlying mating strategies in women. Further, four patterns of female mating style emerged upon review of participant factor scores and are discussed within an evolutionary context.

  1. Salmonellosis outcomes differ substantially by serotype.

    PubMed

    Jones, Timothy F; Ingram, L Amanda; Cieslak, Paul R; Vugia, Duc J; Tobin-D'Angelo, Melissa; Hurd, Sharon; Medus, Carlota; Cronquist, Alicia; Angulo, Frederick J

    2008-07-01

    Most human infections are caused by closely related serotypes within 1 species of Salmonella. Few data are available on differences in severity of disease among common serotypes. We examined data from all cases of Salmonella infection in FoodNet states during 1996-2006. Data included serotype, specimen source, hospitalization, and outcome. Among 46,639 cases, 687 serotypes were identified. Overall, 41,624 isolates (89%) were from stool specimens, 2524 (5%) were from blood, and 1669 (4%) were from urine; 10,393 (22%) cases required hospitalization, and death occurred in 219 (0.5%). The case fatality rate for S. Newport (0.3%) was significantly lower than for Typhimurium (0.6%); Dublin (3.0%) was higher. With respect to invasive disease, 13 serotypes had a significantly higher proportion than Typhimurium (6%), including Enteritidis (7%), Heidelberg (13%), Choleraesuis (57%), and Dublin (64%); 13 serotypes were significantly less likely to be invasive. Twelve serotypes, including Enteritidis (21%) and Javiana (21%), were less likely to cause hospitalization than Typhimurium (24%); Choleraesuis (60%) was significantly more so. Salmonella serotypes are closely related genetically yet differ significantly in their pathogenic potentials. Understanding the mechanisms responsible for this may be key to a more general understanding of the invasiveness of intestinal bacterial infections.

  2. Identification and serotyping of Ornithobacterium rhinotracheale.

    PubMed Central

    van Empel, P; van den Bosch, H; Loeffen, P; Storm, P

    1997-01-01

    In the present study 443 strains of Ornithobacterium rhinotracheale, a causative agent of respiratory disease in fowl, were investigated biochemically and serologically. In both ways O. rhinotracheale could be differentiated from other gram-negative rods and, more particularly, from the Pasteurella-like bacteria potentially pathogenic for fowl. For the biochemical characterization of O. rhinotracheale the API 2ONE identification strip proved to be useful, although O. rhinotracheale is not included in the API system. Serologically, by using monovalent antisera in agar gel precipitation (AGP) tests and enzyme-linked immunosorbent assays (ELISAs), seven serotypes (serotypes A to G) of O. rhinotracheale could be discriminated. The AGP test was chosen as the preferred method to be used for serotyping. Isolates of serotype A were found to be the most prevalent, especially in chickens. Isolates from turkeys were more heterogeneously divided over the serotypes. Some strains showed cross-reactivity between serotypes A, B, and E. Five O. rhinotracheale strains could not be serotyped with the available antisera. Relationships between the geographic origin and the serotypes were found. By the ELISA the presence of antibodies against O. rhinotracheale could be detected in 1-day-old birds as well as in birds with clinical signs, and therefore, it might be useful for diagnostic purposes. PMID:9003608

  3. Identification and serotyping of Ornithobacterium rhinotracheale.

    PubMed

    van Empel, P; van den Bosch, H; Loeffen, P; Storm, P

    1997-02-01

    In the present study 443 strains of Ornithobacterium rhinotracheale, a causative agent of respiratory disease in fowl, were investigated biochemically and serologically. In both ways O. rhinotracheale could be differentiated from other gram-negative rods and, more particularly, from the Pasteurella-like bacteria potentially pathogenic for fowl. For the biochemical characterization of O. rhinotracheale the API 2ONE identification strip proved to be useful, although O. rhinotracheale is not included in the API system. Serologically, by using monovalent antisera in agar gel precipitation (AGP) tests and enzyme-linked immunosorbent assays (ELISAs), seven serotypes (serotypes A to G) of O. rhinotracheale could be discriminated. The AGP test was chosen as the preferred method to be used for serotyping. Isolates of serotype A were found to be the most prevalent, especially in chickens. Isolates from turkeys were more heterogeneously divided over the serotypes. Some strains showed cross-reactivity between serotypes A, B, and E. Five O. rhinotracheale strains could not be serotyped with the available antisera. Relationships between the geographic origin and the serotypes were found. By the ELISA the presence of antibodies against O. rhinotracheale could be detected in 1-day-old birds as well as in birds with clinical signs, and therefore, it might be useful for diagnostic purposes.

  4. Frequency and molecular characterization of invasive isolates of Streptococcus pneumoniae serotypes 6C and 6D in Colombia.

    PubMed

    Parra, Eliana Liseth; Duarte, Carolina; Rodríguez, Karina; Sanabria, Olga; Moreno, Jaime

    2017-05-01

    Serogroup 6 of Streptococcus pneumoniae initially consisted of the 6A and 6B serotypes, but in recent years, the 6C and 6D serotypes were reported. The aim of this study was to determine the frequency and molecular characterization of invasive S. pneumoniae isolates serotypes 6C and 6D in Colombia, from 1994 to 2013. All the isolates recovered during the surveillance from 1994 to 2013, and identified as 6A or 6B, were re-tested to detect the serotypes 6C and 6D. The serotyping was performed using the Quellung reaction and PCR. The susceptibility testing was performed on penicillin, erythromycin, ceftriaxone, trimethoprim/sulfamethoxazole, chloramphenicol, tetracycline and vancomycin. Molecular typing was performed using pulsed-field gel electrophoresis and multilocus sequence typing. From a total of 271 and 350 isolates serotyped previously as serotypes 6A and 6B, 61 (22.5%) and 15 (4.3%) were recognized as 6C and 6D, respectively. Isolates presented with low resistance to antimicrobials. Serotype 6C isolates were mainly associated with ST9007 (42.6%) and ST9008 (19.7%), and serotype 6D isolates with ST1135 (80%). This study showed the circulation of serotype 6C and 6D in Colombia between 1994 and 2013, information that is important to determine the dynamics of these recently described serotypes. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  5. ASYMMETRY IN SEXUAL PHEROMONES IS NOT REQUIRED FOR ASCOMYCETE MATING

    PubMed Central

    Gonçalves-Sá, Joana; Murray, Andrew

    2011-01-01

    SUMMARY Background We investigated the determinants of sexual identity in the budding yeast, Saccharomyces cerevisiae. The higher fungi are divided into the Ascomycetes and the Basidiomycetes. Most Ascomycetes have two mating types: one (called α in yeasts and MAT1-1 in filamentous fungi) produces a small, unmodified, peptide pheromone, and the other (a in yeasts and MAT1-2 in filamentous fungi) produces a peptide pheromone conjugated to a C terminal farnesyl group that makes it very hydrophobic. In the Basidiomycetes, all pheromones are lipid-modified, and this difference is a distinguishing feature between the phyla. We asked whether the asymmetry in pheromone modification is required for successful mating in Ascomycetes. Results We cloned receptor and pheromone genes from a filamentous Ascomycete and a Basidiomycete and expressed these in the budding yeast, Saccharomyces cerevisiae, to generate novel, alternative mating pairs. We find that two yeast cells can mate even when both cells secrete a-like or α-like peptides. Importantly, this is true regardless of whether the cells express the a- or α-mating type loci, which control the expression of other, sex-specific genes, in addition to the pheromones and pheromone receptors. Conclusions We demonstrate that the asymmetric pheromone modification is not required for successful mating of ascomycete fungi and confirm that, in budding yeast, the primary determinants of mating are the specificity of the receptors and their corresponding pheromones. PMID:21835624

  6. Asymmetry in sexual pheromones is not required for ascomycete mating.

    PubMed

    Gonçalves-Sá, Joana; Murray, Andrew

    2011-08-23

    We investigated the determinants of sexual identity in the budding yeast Saccharomyces cerevisiae. The higher fungi are divided into the ascomycetes and the basidiomycetes. Most ascomycetes have two mating types: one (called α in yeasts and MAT1-1 in filamentous fungi) produces a small, unmodified, peptide pheromone, and the other (a in yeasts and MAT1-2 in filamentous fungi) produces a peptide pheromone conjugated to a C-terminal farnesyl group that makes it very hydrophobic. In the basidiomycetes, all pheromones are lipid-modified, and this difference is a distinguishing feature between the phyla. We asked whether the asymmetry in pheromone modification is required for successful mating in ascomycetes. We cloned receptor and pheromone genes from a filamentous ascomycete and a basidiomycete and expressed these in the budding yeast, Saccharomyces cerevisiae, to generate novel, alternative mating pairs. We find that two yeast cells can mate even when both cells secrete a-like or α-like peptides. Importantly, this is true regardless of whether the cells express the a- or α-mating-type loci, which control the expression of other, sex-specific genes, in addition to the pheromones and pheromone receptors. We demonstrate that the asymmetric pheromone modification is not required for successful mating of ascomycete fungi and confirm that, in budding yeast, the primary determinants of mating are the specificity of the receptors and their corresponding pheromones. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Comparison between methods for serotyping of Candida albicans produces discrepancies in results.

    PubMed Central

    Brawner, D L

    1991-01-01

    Serotyping of 101 clinical isolates of Candida albicans was done with two sets of Hasenclever original anti-Candida typing sera (HSN 1 and 2) and Iatron Candida Check factor 6 typing serum (IF6). The results of these two methods were compared with slide agglutination reactions of yeast with monoclonal antibody H9. Agglutination reactions with this antibody have been previously shown to correlate with serotype. Results indicate the following correlations: between HSN 1 and HSN 2 serotyping, 93% (kappa = 0.85; 95% confidence interval [CI], 0.70 to 0.99); between IF6 and HSN 1, 60% (kappa = 0.39, 95% CI, 0.19 to 0.58); and between IF6 and HSN 2, 74% (kappa = 0.77; 95% CI, 0.64 to 0.90). Results with HSN 1 and 2 antisera correlated with H9 reactivity at 85 and 89% (kappa = 0.88; 95% CI, 0.75 to 1.00; and kappa = 0.85; CI, 0.70 to 0.99, respectively), while agreement between IF6 and H9 reactivities was less than or equal to 64% (kappa less than or equal to 0.43; 95% CI, 0.14 to 0.60). Autoagglutination of yeast during IF6 serotyping occurred with 21 of the 101 (20.8%) yeast strains. In every case, these yeast strains were serotyped by the HSN methods without autoagglutination and were uniformly type B. This study implies that it may not be possible to make valid comparisons between studies which compare serotype prevalence unless the same methods are used to serotype the yeast. The practicality and utility of serotyping in epidemiological studies are discussed, as are some of the problems associated with the available methods. PMID:2056036

  8. Mating programs including genomic relationships

    USDA-ARS?s Scientific Manuscript database

    Computer mating programs have helped breeders minimize pedigree inbreeding and avoid recessive defects by mating animals with parents that have fewer common ancestors. With genomic selection, breed associations, AI organizations, and on-farm software providers could use new programs to minimize geno...

  9. Positive assortative mating between recently described sympatric morphs of Icelandic sticklebacks

    PubMed Central

    Ólafsdóttir, Gudbjörg Á; Ritchie, Michael G; Snorrason, Sigurdur S

    2006-01-01

    Recently, models of sympatric speciation have suggested that assortative mating can develop between sympatric morphs due to divergence in an ecologically important character. For example, in sympatric pairs of threespine stickleback (Gasterosteus aculeatus L.) size-assortative mating seems to be instrumental in reproductive isolation. Here, we examine courtship behaviour and assortative mating of newly described sympatric stickleback morphs in Lake Thingvallavatn, Iceland. We find that the two morphs show strong positive assortative mating. However, the mechanism involved in mate choice does not seem to be as straightforward as in other similar systems of sympatric stickleback morphs and may involve variation in nest type. PMID:17148375

  10. Diversity of rotavirus serotypes in Mexican infants with gastroenteritis.

    PubMed Central

    Padilla-Noriega, L; Arias, C F; López, S; Puerto, F; Snodgrass, D R; Taniguchi, K; Greenberg, H B

    1990-01-01

    One hundred thirty-two stool specimens from infants with rotavirus gastroenteritis hospitalized in two Mexican cities (Mexico City and Mérida) were examined by serotype- and subgroup-specific enzyme immunoassays. Among them, 38 (29%) were serotype 1, 15 (11%) were serotype 2, 13 (10%) were serotype 3, 22 (17%) were serotype 4, none was serotype 5 or 6, and 44 (33%) could not be serotyped. By subgrouping, 121 specimens were characterized as follows: 24 (18%) were subgroup 1, 97 (74%) were subgroup 2, and none had both subgroup specificities. While serotype 1 rotavirus predominated in the Mexico City area for 4 consecutive years (1984 to 1987), serotype 4 predominated in Mérida during the single epidemic season studied (1985). These data demonstrate that all four primary human rotavirus serotypes circulated in Mexico, with serotype 1 being the most prevalent. The seroneutralization responses of 14 of the 22 patients infected with serotype 4 strains had been previously studied. Of these 14 infants, 11 appeared to have primary infections, as indicated by absence of neutralizing antibodies in the acute-phase sera and their young age (8 months on average) at the time of illness. Seven patients seroresponded to serotypes 1 and 4; two seroresponded to serotypes 1, 3, and 4; three seroresponded to serotype 1; and two had low-level seroresponses to serotype 3 or 4. These data indicate that heterotypic neutralizing antibody responses occur frequently following infection with serotype 4 rotaviruses. PMID:2166073

  11. Mating with large males decreases the immune defence of females in Drosophila melanogaster.

    PubMed

    Imroze, K; Prasad, N G

    2011-12-01

    Mating has been widely reported to be a costly event for females. Studies indicate that female cost of mating in terms of fecundity and survivorship can be affected by their mates, leading to antagonistic coevolution between the sexes. However, as of now, there is no evidence that the female cost of mating in terms of immune defence is affected by their mates. We assess the effect of different sized males on antibacterial immune defence and reproductive fitness of their mates. We used a large outbred population of Drososphila melanogaster as the host and Serratia marcescens as the pathogen. We generated three different male phenotypes: small, medium and large, by manipulating larval densities. Compared to females mating with small males, those mating with large males had higher bacterial loads and lower fecundity. There was no significant effect of male phenotype on the fraction of females mated or copulation duration (an indicator of ejaculate investment). Thus, our study is the first clear demonstration that male phenotype can affect the cost of mating to females in terms of their antibacterial immune defence. Mating with large males imposes an additional cost of mating to females in terms of reduced immune defence. The observed results are very likely due to qualitative/quantitative differences in the ejaculates of the three different types of males. If the phenotypic variation that we observed in males in our study is mirrored by genetic variation, then, it can potentially lead to antagonistic coevolution of the sexes over immune defence.

  12. Assortative mating without assortative preference.

    PubMed

    Xie, Yu; Cheng, Siwei; Zhou, Xiang

    2015-05-12

    Assortative mating--marriage of a man and a woman with similar social characteristics--is a commonly observed phenomenon. In the existing literature in both sociology and economics, this phenomenon has mainly been attributed to individuals' conscious preferences for assortative mating. In this paper, we show that patterns of assortative mating may arise from another structural source even if individuals do not have assortative preferences or possess complementary attributes: dynamic processes of marriages in a closed system. For a given cohort of youth in a finite population, as the percentage of married persons increases, unmarried persons who newly enter marriage are systematically different from those who married earlier, giving rise to the phenomenon of assortative mating. We use microsimulation methods to illustrate this dynamic process, using first the conventional deterministic Gale-Shapley model, then a probabilistic Gale-Shapley model, and then two versions of the encounter mating model.

  13. Porcine Teschoviruses Comprise at Least Eleven Distinct Serotypes: Molecular and Evolutionary Aspects

    PubMed Central

    Zell, Roland; Dauber, Malte; Krumbholz, Andi; Henke, Andreas; Birch-Hirschfeld, Eckhard; Stelzner, Axel; Prager, Dieter; Wurm, Rudiger

    2001-01-01

    Nucleotide sequencing and phylogenetic analysis of 10 recognized prototype strains of the porcine enterovirus (PEV) cytopathic effect (CPE) group I reveals a close relationship of the viral genomes to the previously sequenced strain F65, supporting the concept of a reclassification of this virus group into a new picornavirus genus. Also, nucleotide sequences of the polyprotein-encoding genome region or the P1 region of 28 historic strains and recent field isolates were determined. The data suggest that several closely related but antigenically and molecular distinct serotypes constitute one species within the proposed genus Teschovirus. Based on sequence data and serological data, we propose a new serotype with strain Dresden as prototype. This hitherto unrecognized serotype is closely related to porcine teschovirus 1 (PTV-1, former PEV-1), but induces type-specific neutralizing antibodies. Sequencing of field isolates collected from animals presenting with neurological disorders prove that other serotypes than PTV-1 may also cause polioencephalomyelitis of swine. PMID:11160660

  14. Comparative investigations of Klebsiella species of clinical origin: plasmid patterns, biochemical reactions, antibiotic resistances and serotypes.

    PubMed

    Podschun, R; Heineken, P; Ullmann, U; Sonntag, H G

    1986-09-01

    A total of 124 K. pneumoniae and 52 K. oxytoca isolates obtained from clinical specimens was investigated for plasmid patterns, biochemical reactions, antibiotic resistances and serotypes regarding to the distribution and relationships of these characters. A great diversity of plasmid patterns, bio/serotypes and resistance patterns was revealed. About 90% of strains contained plasmid DNA and up to seven plasmid bands per isolate could be shown. For K. pneumoniae, serotype 7 and for K. oxytoca, type 55 were most common. In general, little difference between both species was found and characters were similarly distributed. With respect to the site of isolation, serotype 7 was predominating in K. pneumoniae strains from the respiratory tract. Highly multiple-resistant organism were found in the largest number in specimens from the urogenital tract, in the lowest in specimens from wounds. Extensive statistical analyses did not detect any relationship among the characters investigated.

  15. [The comparative characteristics of the Salmonella serotypes rarely encountered in the Maritime Territory].

    PubMed

    Koval'chuk, N I; Shubin, F N; Khoroshko, V A; Sheverdina, F N; Tarasenko, T T; Kosheleva, N G

    1997-01-01

    The results of the comparative study of the phenotypical properties and the plasmid profile of 63 strains of salmonellae, belonging to 44 serotypes of groups B, C1, C2, C3, D, E1, E4, F. The study revealed that strains of different serotypes had their individual plasmid profile. Strains of the same serotype of salmonellae isolated from similar sources had an identical plasmid profile, while strains isolated from different sources differed in their plasmid profiles, though they might have a similar phenotype. Plasmid analysis was shown to be an effective method for the intraspecific typing of rarely isolated Salmonella serotypes and suitable for use as the basis of the microbiological monitoring of salmonellae.

  16. Evaluation of cross-protection of bluetongue virus serotype 4 with other serotypes in sheep.

    PubMed

    Zulu, Gcwalisile B; Venter, Estelle H

    2014-10-16

    Bluetongue (BT) is a non-contagious disease of sheep and other domestic and wild ruminants caused by the bluetongue virus (BTV). Currently 26 serotypes of the virus have been identified. In South Africa, 22 serotypes have been identified and BT is controlled mainly by annual vaccinations using a freeze-dried live attenuated polyvalent BTV vaccine. The vaccine is constituted of 15 BTV serotypes divided into three separate bottles and the aim is to develop a vaccine using fewer serotypes without compromising the immunity against the disease. This study is based on previously reported cross-neutralisation of specific BTV serotypes in in vitro studies. Bluetongue virus serotype 4 was selected for this trial and was tested for cross-protection against serotype 4 (control), 1 (unrelated serotype), 9, 10 and 11 in sheep using the serum neutralisation test. The purpose of the study was to determine possible cross-protection of different serotypes in sheep. Of those vaccinated with BTV-4 and challenged with BTV-1, which is not directly related to BTV-4, 20% were completely protected and 80% showed clinical signs, but the reaction was not as severe as amongst the unvaccinated animals. In the group challenged with BTV-10, some showed good protection and some became very sick. Those challenged with BTV-9 and BTV-11 had good protection. The results showed that BTV-4 does not only elicit a specific immune response but can also protect against other serotypes.

  17. The cps locus of Streptococcus suis serotype 16: development of a serotype-specific PCR assay.

    PubMed

    Wang, Kaicheng; Fan, Weixing; Wisselink, Henk; Lu, Chengping

    2011-12-15

    Streptococcus suis serotype 16 can infect pigs and humans. We describe the identification and the characterization of the capsular polysaccharides synthesis locus of S. suis serotype 16. Using PCR primers flanking the capsular polysaccharides synthesis locus, a 30,101-bp fragment was amplified. Twenty-nine open reading frames related to transcriptional regulation, glycosyl transfer, oligosaccharide repeat unit polymerization, polysaccharide transport, sialic acid synthesis and modification were identified. The data suggests that the serotype 16 capsule is synthesized by a Wzy-dependent pathway. So far, no rapid and sensitive diagnostic method is available for detection of serotype 16 isolates. A serotype specific PCR test for the rapid and sensitive detection of S. suis serotype 16 was developed. Cross hybridization experiments of individual cps genes with chromosomal DNAs of 33 serotypes showed that the cps16G and cps16K genes hybridized with serotype 16 only. Primers based on cps16G were used to develop a serotype 16 specific PCR. The PCR assay was successfully used to identify S. suis serotype 16 in the 99 Chinese S. suis clinical isolates and 8 European isolates.

  18. Nasopharyngeal carriage of individual Streptococcus pneumoniae serotypes during pediatric radiologically confirmed community acquired pneumonia following PCV7 introduction in Switzerland.

    PubMed

    Chappuy, Hélène; Keitel, Kristina; Gehri, Mario; Tabin, René; Robitaille, Lynda; Raymond, Frederic; Corbeil, Jacques; Maspoli, Veronica; Bouazza, Naim; Alcoba, Gabriel; Lacroix, Laurence; Manzano, Sergio; Galetto-Lacour, Annick; Gervaix, Alain

    2013-07-31

    Community-acquired pneumonia (CAP) is a serious cause of morbidity among children in developed countries. The real impact of 7-valent pneumococcal conjugate vaccine (PCV7) on pneumococcal pneumonia is difficult to assess accurately. Children aged ≤16 years with clinical and radiological pneumonia were enrolled in a multicenter prospective study. Children aged ≤16 years admitted for a minor elective surgery was recruited as controls. Nasopharyngeal samples for PCR serotyping of S. pneumoniae were obtained in both groups. Informations on age, gender, PCV7 vaccination status, day care/school attendance, siblings, tobacco exposure were collected. In children with CAP (n=236), 54% of the nasopharyngeal swabs were PCR-positive for S. pneumoniae compared to 32% in controls (n=105) (p=0.003). Serotype 19A was the most common pneumococcal serotype carried in children with CAP (13%) and in controls (15%). Most common serotypes were non-vaccine types (39.4% for CAP and 47.1% for controls) and serotypes included only in PCV13 (32.3% for CAP and 23.5% for controls). There was no significant difference in vaccine serotype distribution between the two groups. In fully vaccinated children with CAP, the proportion of serotypes carried only in PCV13 was higher (51.4%) than in partially vaccinated or non vaccinated children (27.6% and 28.6% respectively, p=0.037). Two to 4 years following introduction of PCV7, predominant S. pneumoniae serotypes carried in children with CAP were non PCV7 serotypes, and the 6 new serotypes included in PCV13 accounted for 51.4% of carried serotypes in fully vaccinated children.

  19. Female Stick Insects Mate Multiply to Find Compatible Mates.

    PubMed

    Arbuthnott, Devin; Crespi, Bernard J; Schwander, Tanja

    2015-10-01

    Why females of many species mate multiply in the absence of direct benefits remains an open question in evolutionary ecology. Interacting and mating with multiple males can be costly to females in terms of time, resources, predation risk, and disease transmission. A number of indirect genetic benefits have been proposed to explain such behaviors, but the relative importance of these mechanisms in natural systems remains unclear. We tested for several direct and indirect benefits of polyandry in the walking stick Timema cristinae. We found no evidence of direct benefits with respect to longevity or fecundity. However, male × female genotypic interactions affected egg-hatching success and offspring production independent of relatedness, suggesting that mating with certain males benefits females and that the best male may differ for each female. Furthermore, multiply mated females biased paternity toward one or few males, and the extent of this bias was positively correlated to egg-hatching success. Our data, therefore, provide evidence for indirect benefits through compatibility effects in this species. By mating multiply, females may improve their chances of mating with a compatible male if compatibility cannot be assessed before mating. Such compatibility effects can explain the evolution and maintenance of polyandry in Timema and many other species.

  20. You Mate, I Mate: Macaque Females Synchronize Sex not Cycles

    PubMed Central