Native trees of the Northeast Argentine: natural hosts of the Cryptococcus neoformans-Cryptococcus gattii species complex.

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Cattana, Maria Emilia; Sosa, María de Los Ángeles; Fernández, Mariana; Rojas, Florencia; Mangiaterra, Magdalena; Giusiano, Gustavo

2014-01-01

In Argentina, information about epidemiology and environmental distribution of Cryptococcus is scarce. The city of Resistencia borders with Brazil and Paraguay where this fungus is endemic. All these supported the need to investigate the ecology of the genus and the epidemiology of cryptococcosis in this area. The aim was to investigate the presence of species of Cryptococcus neoformans-Cryptococcus gattii complex and their genotypes in trees of the city of Resistencia. One hundred and five trees were sampled by swabbing technique. The isolates were identified using conventional and commercial methods and genotyped by PCR-RFLP (Restriction Fragment Length Polymorphism). Cryptococcus was found in 7 out of the total trees. 6 out of 7 Cryptococcus isolates were identified as C. neoformans and one as C. gattii. C. gattii was isolated from Grevillea robusta. C. neoformans strains were isolated from Tabebuia avellanedae and Peltophorum dubium. Genotyping showed that all C. neoformans belonged to the VNI type and C. gattii belonged to the VGI type. This represents the first study on the ecology of Cryptococcus spp. associated to trees from northeastern Argentina, and the first report describing Grevillea robusta as a host of members of this fungal genus. Another finding is the isolation of C. neoformans from Tabebuia avellanedae and Peltophorum dubium, both tree species native to northeastern Argentina. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

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Cho, Minsu; Hu, Guanggan; Caza, Mélissa; Horianopoulos, Linda C; Kronstad, James W; Jung, Won Hee

2018-01-01

Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

The Genome of the Basidiomycetous Yeast and Human Pathogen Cryptococcus neoformans

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Loftus, Brendan J.; Fung, Eula; Roncaglia, Paola; Rowley, Don; Amedeo, Paolo; Bruno, Dan; Vamathevan, Jessica; Miranda, Molly; Anderson, Iain J.; Fraser, James A.; Allen, Jonathan E.; Bosdet, Ian E.; Brent, Michael R.; Chiu, Readman; Doering, Tamara L.; Donlin, Maureen J.; D’Souza, Cletus A.; Fox, Deborah S.; Grinberg, Viktoriya; Fu, Jianmin; Fukushima, Marilyn; Haas, Brian J.; Huang, James C.; Janbon, Guilhem; Jones, Steven J. M.; Koo, Hean L.; Krzywinski, Martin I.; Kwon-Chung, June K.; Lengeler, Klaus B.; Maiti, Rama; Marra, Marco A.; Marra, Robert E.; Mathewson, Carrie A.; Mitchell, Thomas G.; Pertea, Mihaela; Riggs, Florenta R.; Salzberg, Steven L.; Schein, Jacqueline E.; Shvartsbeyn, Alla; Shin, Heesun; Shumway, Martin; Specht, Charles A.; Suh, Bernard B.; Tenney, Aaron; Utterback, Terry R.; Wickes, Brian L.; Wortman, Jennifer R.; Wye, Natasja H.; Kronstad, James W.; Lodge, Jennifer K.; Heitman, Joseph; Davis, Ronald W.; Fraser, Claire M.; Hyman, Richard W.

2012-01-01

Cryptococcus neoformans is a basidiomycetous yeast ubiquitous in the environment, a model for fungal pathogenesis, and an opportunistic human pathogen of global importance. We have sequenced its ~20-megabase genome, which contains ~6500 intron-rich gene structures and encodes a transcriptome abundant in alternatively spliced and antisense messages. The genome is rich in transposons, many of which cluster at candidate centromeric regions. The presence of these transposons may drive karyotype instability and phenotypic variation. C. neoformans encodes unique genes that may contribute to its unusual virulence properties, and comparison of two phenotypically distinct strains reveals variation in gene content in addition to sequence polymorphisms between the genomes. PMID:15653466

Classification of Cryptococcus neoformans and yeast-like fungus isolates from pigeon droppings by colony phenotyping and ITS genotyping and their seasonal variations in Korea.

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Chae, H S; Jang, G E; Kim, N H; Son, H R; Lee, J H; Kim, S H; Park, G N; Jo, H J; Kim, J T; Chang, K S

2012-03-01

Cryptococcus neoformans (C neoformans) is a frequent cause of invasive fungal disease in immunocompromised human hosts. Ninety-eight samples of pigeon droppings were collected from the pigeon shelters in Seoul, and cultured on birdseed agar (BSA) and Sabouraud dextrose agar (SDA). One hundred yeast-like colonies were selected and identified via phenotype characteristics, such as colony morphology and biochemical characteristics. This was then followed with genotyping via sequencing of the internal transcribed spacer (ITS) region. The colonies were classified into four kinds of colony color types: brown type (BrT), beige type (BeT), pink type (PT), and white type (WT). Numbers of isolated BrT, BeT, PT, and WT colonies were 22 (22%), 30 (30%), 19 (19%), and 39 (39%), respectively. All BrT colonies were identified as C neoformans. BeT were identified as 19 isolates of Cryptococcus laurentii, 10 isolates of Malassezia furfur, and 1 isolate of Cryptococcus uniguttulatus. PT was divided into two colony color types: light-PT (l-PT) and deep-PT (d-PT). Eighteen of l-PT and one of d-PT were identified as Rhodotorula glutinis and Rhodotorula mucilaginosa, respectively. WT were identified as 34 isolates of Cryptococcus guilliermondii, 3 isolates of Cryptococcus zeylanoides, 1 isolate of Cryptococcus sake, and 1 isolate of Stephanoascus ciferrii. Most strains were classified identically with the use of either phenotype or genotyping techniques, but C uniguttulatus and C sake classified by phenotyping were Pseudozyma aphidis and Cryptococcus famata by genotyping. This rapid screening technique of pathogenic yeast-like fungi by only colony characteristics is also expected to be very useful for primary yeast screening. Additionally, we investigated the seasonal variations of C neoformans and other yeast-like fungi from 379 pigeon-dropping samples that were collected from February 2011 to March 2011. We isolated 685 yeast-like fungi from the samples. Almost all C neoformans and

The effects of chloramphenicol and 60Co irradiation on the experimental mycosis in mice inoculated intragastrically with two kinds of pathogenic yeast-like fungi

International Nuclear Information System (INIS)

Kitamura, Isamu

1975-01-01

Two kinds of pathogenic yeast, Cryptococcus neoformans and Candida albicans were inoculated into the stomachs of mice. The effects of intragastric administration of chloramphenicol (CM) and systemic irradiation with 60 Co on the acceralation of infection were studied in intragastrically inoculated mice. When Cryptococcus neoformans were simply inoculated, it was difficult for them to reside in the alimentary canal to cause infection. In case of candida albicans inoculated simply, they were also unable to induce infection though they remained in the alimentary canal for a long time. In the experiment combining intragastric administration of the fungi and CM some mice contracted the disease and died. The effect of CM in causing infection was not proved. In the experiments combining 60 Co irradiation and intragastric administration of CM and fungi, a high incidence of fungus infection was noted with both Cryptococcus neoformans and Candida albicans. Fungus lesions were observed in many organs, and in all of the mice which died systemic fungus lesions were noted. It was shown that systemic irradiation with 60 Co had a specific effect on facilitating the infection. In these studies no difference was observed in the incidence of the fungus disease in respect of the origin of the causative fungi. (J.P.N.)

Adaptive Immunity to Cryptococcus neoformans Infections

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Liliane Mukaremera

2017-11-01

Full Text Available The Cryptococcus neoformans/Cryptococcus gattii species complex is a group of fungal pathogens with different phenotypic and genotypic diversity that cause disease in immunocompromised patients as well as in healthy individuals. The immune response resulting from the interaction between Cryptococcus and the host immune system is a key determinant of the disease outcome. The species C. neoformans causes the majority of human infections, and therefore almost all immunological studies focused on C. neoformans infections. Thus, this review presents current understanding on the role of adaptive immunity during C. neoformans infections both in humans and in animal models of disease.

Polymorphism in Mitochondrial Group I Introns among Cryptococcus neoformans and Cryptococcus gattii Genotypes and Its Association with Drug Susceptibility

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Felipe E. E. S. Gomes

2018-02-01

Full Text Available Cryptococcosis, one of the most important systemic mycosis in the world, is caused by different genotypes of Cryptococcus neoformans and Cryptococcus gattii, which differ in their ecology, epidemiology, and antifungal susceptibility. Therefore, the search for new molecular markers for genotyping, pathogenicity and drug susceptibility is necessary. Group I introns fulfill the requisites for such task because (i they are polymorphic sequences; (ii their self-splicing is inhibited by some drugs; and (iii their correct splicing under parasitic conditions is indispensable for pathogen survival. Here, we investigated the presence of group I introns in the mitochondrial LSU rRNA gene in 77 Cryptococcus isolates and its possible relation to drug susceptibility. Sequencing revealed two new introns in the LSU rRNA gene. All the introns showed high sequence similarity to other mitochondrial introns from distinct fungi, supporting the hypothesis of an ancient non-allelic invasion. Intron presence was statistically associated with those genotypes reported to be less pathogenic (p < 0.001. Further virulence assays are needed to confirm this finding. In addition, in vitro antifungal tests indicated that the presence of LSU rRNA introns may influence the minimum inhibitory concentration (MIC of amphotericin B and 5-fluorocytosine. These findings point to group I introns in the mitochondrial genome of Cryptococcus as potential molecular markers for antifungal resistance, as well as therapeutic targets.

Creatinine metabolism in Cryptococcus neoformans and Cryptococcus bacillisporus.

OpenAIRE

Polacheck, I; Kwon-Chung, K J

1980-01-01

The pathogenic species of Cryptococcus, C. neoformans and C. bacillisporus, utilized creatinine as a source of nitrogen but not of carbon. Chromatographic and autoradiographic studies suggest that creatinine metabolism in both species involves a single step resulting in the production of methylhydantoin and ammonia. The enzyme responsible for this step, creatinine deiminase, was produced by the cells only in the presence of creatinine in both species. The synthesis of creatinine deiminase was...

Gene Network Polymorphism Illuminates Loss and Retention of Novel RNAi Silencing Components in the Cryptococcus Pathogenic Species Complex.

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Marianna Feretzaki

2016-03-01

Full Text Available RNAi is a ubiquitous pathway that serves central functions throughout eukaryotes, including maintenance of genome stability and repression of transposon expression and movement. However, a number of organisms have lost their RNAi pathways, including the model yeast Saccharomyces cerevisiae, the maize pathogen Ustilago maydis, the human pathogen Cryptococcus deuterogattii, and some human parasite pathogens, suggesting there may be adaptive benefits associated with both retention and loss of RNAi. By comparing the RNAi-deficient genome of the Pacific Northwest Outbreak C. deuterogattii strain R265 with the RNAi-proficient genomes of the Cryptococcus pathogenic species complex, we identified a set of conserved genes that were lost in R265 and all other C. deuterogattii isolates examined. Genetic and molecular analyses reveal several of these lost genes play roles in RNAi pathways. Four novel components were examined further. Znf3 (a zinc finger protein and Qip1 (a homolog of N. crassa Qip were found to be essential for RNAi, while Cpr2 (a constitutive pheromone receptor and Fzc28 (a transcription factor are involved in sex-induced but not mitosis-induced silencing. Our results demonstrate that the mitotic and sex-induced RNAi pathways rely on the same core components, but sex-induced silencing may be a more specific, highly induced variant that involves additional specialized or regulatory components. Our studies further illustrate how gene network polymorphisms involving known components of key cellular pathways can inform identification of novel elements and suggest that RNAi loss may have been a core event in the speciation of C. deuterogattii and possibly contributed to its pathogenic trajectory.

Spread of Rare Fungus from Vancouver Island

Centers for Disease Control (CDC) Podcasts

Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism

3-Bromopyruvate: a novel antifungal agent against the human pathogen Cryptococcus neoformans.

Science.gov (United States)

Dyląg, Mariusz; Lis, Paweł; Niedźwiecka, Katarzyna; Ko, Young H; Pedersen, Peter L; Goffeau, Andre; Ułaszewski, Stanisław

2013-05-03

We have investigated the antifungal activity of the pyruvic acid analogue: 3-bromopyruvate (3-BP). Growth inhibition by 3-BP of 110 strains of yeast-like and filamentous fungi was tested by standard spot tests or microdilution method. The human pathogen Cryptococcus neoformans exhibited a low Minimal Inhibitory Concentration (MIC) of 0.12-0.15 mM 3-BP. The high toxicity of 3-BP toward C. neoformans correlated with high intracellular accumulation of 3-BP and also with low levels of intracellular ATP and glutathione. Weak cytotoxicity towards mammalian cells and lack of resistance conferred by the PDR (Pleiotropic Drug Resistance) network in the yeast Saccharomyces cerevisiae, are other properties of 3-BP that makes it a novel promising anticryptococcal drug. Copyright © 2013 Elsevier Inc. All rights reserved.

Methamphetamine enhances Cryptococcus neoformans pulmonary infection and dissemination to the brain.

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Patel, Dhavan; Desai, Gunjan M; Frases, Susana; Cordero, Radames J B; DeLeon-Rodriguez, Carlos M; Eugenin, Eliseo A; Nosanchuk, Joshua D; Martinez, Luis R

2013-07-30

Methamphetamine (METH) is a major addictive drug of abuse in the United States and worldwide, and its use is linked to HIV acquisition. The encapsulated fungus Cryptococcus neoformans is the most common cause of fungal meningitis in patients with AIDS. In addition to functioning as a central nervous system stimulant, METH has diverse effects on host immunity. Using a systemic mouse model of infection and in vitro assays in order to critically assess the impact of METH on C. neoformans pathogenesis, we demonstrate that METH stimulates fungal adhesion, glucuronoxylomannan (GXM) release, and biofilm formation in the lungs. Interestingly, structural analysis of the capsular polysaccharide of METH-exposed cryptococci revealed that METH alters the carbohydrate composition of this virulence factor, an event of adaptation to external stimuli that can be advantageous to the fungus during pathogenesis. Additionally, we show that METH promotes C. neoformans dissemination from the respiratory tract into the brain parenchyma. Our findings provide novel evidence of the impact of METH abuse on host homeostasis and increased permissiveness to opportunistic microorganisms. Methamphetamine (METH) is a major health threat to our society, as it adversely changes people's behavior, as well as increases the risk for the acquisition of diverse infectious diseases, particularly those that enter through the respiratory tract or skin. This report investigates the effects of METH use on pulmonary infection by the AIDS-related fungus Cryptococcus neoformans. This drug of abuse stimulates colonization and biofilm formation in the lungs, followed by dissemination of the fungus to the central nervous system. Notably, C. neoformans modifies its capsular polysaccharide after METH exposure, highlighting the fungus's ability to adapt to environmental stimuli, a possible explanation for its pathogenesis. The findings may translate into new knowledge and development of therapeutic and public health

Cryptococcus neoformans carried by Odontomachus bauri ants

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Mariana Santos de Jesus

2012-06-01

Full Text Available Cryptococcus neoformans is the most common causative agent of cryptococcosis worldwide. Although this fungus has been isolated from a variety of organic substrates, several studies suggest that hollow trees constitute an important natural niche for C. neoformans. A previously surveyed hollow of a living pink shower tree (Cassia grandis positive for C. neoformans in the city of Rio de Janeiro, Brazil, was chosen for further investigation. Odontomachus bauri ants (trap-jaw ants found inside the hollow were collected for evaluation as possible carriers of Cryptococcus spp. Two out of 10 ants were found to carry phenoloxidase-positive colonies identified as C. neoformans molecular types VNI and VNII. The ants may have acted as a mechanical vector of C. neoformans and possibly contributed to the dispersal of the fungi from one substrate to another. To the best of our knowledge, this is the first report on the association of C. neoformans with ants of the genus Odontomachus.

Unisexual reproduction of Cryptococcus gattii.

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Sujal S Phadke

Full Text Available Cryptococcus gattii is a basidiomycetous human fungal pathogen that typically causes infection in tropical and subtropical regions and is responsible for an ongoing outbreak in immunocompetent individuals on Vancouver Island and in the Pacific Northwest of the US. Pathogenesis of this species may be linked to its sexual cycle that generates infectious propagules called basidiospores. A marked predominance of only one mating type (α in clinical and environmental isolates suggests that a-α opposite-sex reproduction may be infrequent or geographically restricted, raising the possibility of an alternative unisexual cycle involving cells of only α mating type, as discovered previously in the related pathogenic species Cryptococcus neoformans. Here we report observation of hallmark features of unisexual reproduction in a clinical isolate of C. gattii (isolate 97/433 and describe genetic and environmental factors conducive to this sexual cycle. Our results are consistent with population genetic evidence of recombination in the largely unisexual populations of C. gattii and provide a useful genetic model for understanding how novel modes of sexual reproduction may contribute to evolution and virulence in this species.

Isolation and molecular characterization of Cryptococcus species isolated from pigeon nests and Eucalyptus trees.

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Kamari, A; Sepahvand, A; Mohammadi, R

2017-06-01

Cryptococcus species are pathogenic and non-pathogenic basidiomycete yeasts that are found widely in the environment. Based on phenotypic methods, this genus has many species; however, its taxonomy is presently being re-evaluated by modern techniques. The Cryptococcus species complex includes two sibling taxa of Cryptococcus neoformans and Cryptococcus gattii . We aimed to investigate the possible distribution of Cryptococcus species in pigeon nests and Eucalyptus trees in Ilam, Iran, using molecular techniques. Two hundred and seventy-four specimens were collected from pigeon nests and Eucalyptus trees during 2016-2017. All the specimens were sub-cultured on Sabouraud Glucose Agar with chloramphenicol and bird seed agar. For molecular identification, the ITS15.8SITS2 rDNA region was amplified using the first and fourth internal transcribed spacer (ITS1 and ITS4, respectively) primers. The purified products were applied for cycle sequencing reactions in forward direction with ITS1 primer. The obtained results were analyzed with Chromas 2.3. Thirty-three out of 186 cultures (17.7%) and 11 out of 88 cultures (12.5%) were positive among pigeon nest and Eucalyptus tree specimens, respectively. Cryptococcus albidus (17.2%), C. albidus var. kuetzingii (3.4%), C. adeliensis (3.4%), C. uzbekistanensis (3.4%), and C. neoformans var. grubii (3.4%) were isolated from pigeon nests, and Cryptococcus adeliensis (25%) was the only Cryptococcus species isolated from Eucalyptus trees. The presence of pigeons and Eucalyptus trees in the vicinity of some particular places such as rest homes and hospitals should be considered as a risk factor for the immunocompromised population.

Spread of Rare Fungus from Vancouver Island

Centers for Disease Control (CDC) Podcasts

2006-12-20

Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism.  Created: 12/20/2006 by Emerging Infectious Diseases.   Date Released: 12/29/2006.

Environmental isolation, biochemical identification, and antifungal drug susceptibility of Cryptococcus species

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Valter Luis Iost Teodoro

2013-12-01

Full Text Available Introduction The incidence of opportunistic fungal infections has increased in recent years and is considered an important public health problem. Among systemic and opportunistic mycoses, cryptococcosis is distinguished by its clinical importance due to the increased risk of infection in individuals infected by human immunodeficiency virus. Methods To determine the occurrence of pathogenic Cryptococcus in pigeon excrement in the City of Araraquara, samples were collected from nine environments, including state and municipal schools, abandoned buildings, parks, and a hospital. The isolates were identified using classical tests, and susceptibility testing for the antifungal drugs (fluconazole, itraconazole, voriconazole, and amphotericin B independently was also performed. After collection, the excrement samples were plated on Niger agar and incubated at room temperature. Results A total of 87 bird dropping samples were collected, and 66.6% were positive for the genus Cryptococcus. The following species were identified: Cryptococcus neoformans (17.2%, Cryptococcus gattii (5.2%, Cryptococcus ater (3.5%, Cryptococcus laurentti (1.7%, and Cryptococcus luteolus (1.7%. A total of 70.7% of the isolates were not identified to the species level and are referred to as Cryptococcus spp. throughout the manuscript. Conclusions Although none of the isolates demonstrated resistance to antifungal drugs, the identification of infested areas, the proper control of birds, and the disinfection of these environments are essential for the epidemiological control of cryptococcosis.

Role of Sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: potential applications for vaccine development.

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Rella, Antonella; Mor, Visesato; Farnoud, Amir M; Singh, Ashutosh; Shamseddine, Achraf A; Ivanova, Elitza; Carpino, Nicholas; Montagna, Maria T; Luberto, Chiara; Del Poeta, Maurizio

2015-01-01

Cryptococcosis caused by Cryptococcus neoformans and Cryptococcus gattii affects a large population and is a cause of significant morbidity and mortality. Despite its public health burden, there are currently no vaccines against cryptococcosis and new strategies against such infections are needed. In this study, we demonstrate that C. neoformans has the biochemical ability to metabolize sterylglucosides (SGs), a class of immunomodulatory glycolipids. Genetic manipulations that eliminate cryptococccal sterylglucosidase lead to the accumulation of SGs and generate a mutant strain (Δsgl1) that is non-pathogenic in the mouse models of cryptococcosis. Interestingly, this mutant strain acts as a vaccine strain and protects mice against cryptococcosis following infection with C. neoformans or C. gattii. The immunity induced by the Δsgl1 strain is not CD4(+) T-cells dependent. Immunocompromised mice, which lack CD4(+) T-cells, are able to control the infection by Δsgl1 and acquire immunity against the challenge by wild-type C. neoformans following vaccination with the Δsgl1 strain. These findings are particularly important in the context of HIV/AIDS immune deficiency and suggest that the Δsgl1 strain might provide a potential vaccination strategy against cryptococcosis.

A novel xylosylphosphotransferase activity discovered in Cryptococcus neoformans

DEFF Research Database (Denmark)

Reilly, Morgann C; Levery, Steven B; Castle, Sherry A

2009-01-01

Cryptococcus neoformans is a fungal pathogen that causes serious disease in immunocompromised individuals. The organism produces a distinctive polysaccharide capsule that is necessary for its virulence, a predominantly polysaccharide cell wall, and a variety of protein- and lipid-linked glycans...

Cell wall modifications during conidial maturation of the human pathogenic fungus Pseudallescheria boydii

NARCIS (Netherlands)

Ghamrawi, Sarah; Rénier, Gilles; Saulnier, Patrick; Cuenot, Stéphane; Zykwinska, Agata; Dutilh, Bas E; Thornton, Christopher; Faure, Sébastien; Bouchara, Jean-Philippe

Progress in extending the life expectancy of cystic fibrosis (CF) patients remains jeopardized by the increasing incidence of fungal respiratory infections. Pseudallescheria boydii (P. boydii), an emerging pathogen of humans, is a filamentous fungus frequently isolated from the respiratory

Cell Wall Modifications during Conidial Maturation of the Human Pathogenic Fungus Pseudallescheria boydii

NARCIS (Netherlands)

Ghamrawi, S.; Renier, G.; Saulnier, P.; Cuenot, S.; Zykwinska, A.; Dutilh, B.E.; Thornton, C.; Faure, S.; Bouchara, J.P.

2014-01-01

Progress in extending the life expectancy of cystic fibrosis (CF) patients remains jeopardized by the increasing incidence of fungal respiratory infections. Pseudallescheria boydii (P. boydii), an emerging pathogen of humans, is a filamentous fungus frequently isolated from the respiratory

Mosquitocidal activity of a naturally occurring isochroman and synthetic analogs from the plant pathogenic fungus, Diaporthe eres against Aedes aegypti ( Diptera: Culicidae)

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The culture filtrate of a plant pathogenic fungus that infects English ivy (Hegera helix) was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for pathogenic effects on the plant Hegera helix has been identified as Diaporthe eres by molecular technique...

Discovery of a modified tetrapolar sexual cycle in Cryptococcus amylolentus and the evolution of MAT in the Cryptococcus species complex.

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Keisha Findley

Full Text Available Sexual reproduction in fungi is governed by a specialized genomic region called the mating-type locus (MAT. The human fungal pathogenic and basidiomycetous yeast Cryptococcus neoformans has evolved a bipolar mating system (a, α in which the MAT locus is unusually large (>100 kb and encodes >20 genes including homeodomain (HD and pheromone/receptor (P/R genes. To understand how this unique bipolar mating system evolved, we investigated MAT in the closely related species Tsuchiyaea wingfieldii and Cryptococcus amylolentus and discovered two physically unlinked loci encoding the HD and P/R genes. Interestingly, the HD (B locus sex-specific region is restricted (∼2 kb and encodes two linked and divergently oriented homeodomain genes in contrast to the solo HD genes (SXI1α, SXI2a of C. neoformans and Cryptococcus gattii. The P/R (A locus contains the pheromone and pheromone receptor genes but has expanded considerably compared to other outgroup species (Cryptococcus heveanensis and is linked to many of the genes also found in the MAT locus of the pathogenic Cryptococcus species. Our discovery of a heterothallic sexual cycle for C. amylolentus allowed us to establish the biological roles of the sex-determining regions. Matings between two strains of opposite mating-types (A1B1×A2B2 produced dikaryotic hyphae with fused clamp connections, basidia, and basidiospores. Genotyping progeny using markers linked and unlinked to MAT revealed that meiosis and uniparental mitochondrial inheritance occur during the sexual cycle of C. amylolentus. The sexual cycle is tetrapolar and produces fertile progeny of four mating-types (A1B1, A1B2, A2B1, and A2B2, but a high proportion of progeny are infertile, and fertility is biased towards one parental mating-type (A1B1. Our studies reveal insights into the plasticity and transitions in both mechanisms of sex determination (bipolar versus tetrapolar and sexual reproduction (outcrossing versus inbreeding with

Continental Drift and Speciation of the Cryptococcus neoformans and Cryptococcus gattii Species Complexes

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Arturo Casadevall

2017-04-01

Full Text Available Genomic analysis has placed the origins of two human-pathogenic fungi, the Cryptococcus gattii species complex and the Cryptococcus neoformans species complex, in South America and Africa, respectively. Molecular clock calculations suggest that the two species separated ~80 to 100 million years ago. This time closely approximates the breakup of the supercontinent Pangea, which gave rise to South America and Africa. On the basis of the geographic distribution of these two species complexes and the coincidence of the evolutionary divergence and Pangea breakup times, we propose that a spatial separation caused by continental drift resulted in the emergence of the C. gattii and C. neoformans species complexes from a Pangean ancestor. We note that, despite the spatial and temporal separation that occurred approximately 100 million years ago, these two species complexes are morphologically similar, share virulence factors, and cause very similar diseases. Continuation of these phenotypic characteristics despite ancient separation suggests the maintenance of similar selection pressures throughout geologic ages.

PRM1 and KAR5 function in cell-cell fusion and karyogamy to drive distinct bisexual and unisexual cycles in the Cryptococcus pathogenic species complex.

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Ci Fu

2017-11-01

Full Text Available Sexual reproduction is critical for successful evolution of eukaryotic organisms in adaptation to changing environments. In the opportunistic human fungal pathogens, the Cryptococcus pathogenic species complex, C. neoformans primarily undergoes bisexual reproduction, while C. deneoformans undergoes both unisexual and bisexual reproduction. During both unisexual and bisexual cycles, a common set of genetic circuits regulates a yeast-to-hyphal morphological transition, that produces either monokaryotic or dikaryotic hyphae. As such, both the unisexual and bisexual cycles can generate genotypic and phenotypic diversity de novo. Despite the similarities between these two cycles, genetic and morphological differences exist, such as the absence of an opposite mating-type partner and monokaryotic instead of dikaryotic hyphae during C. deneoformans unisexual cycle. To better understand the similarities and differences between these modes of sexual reproduction, we focused on two cellular processes involved in sexual reproduction: cell-cell fusion and karyogamy. We identified orthologs of the plasma membrane fusion protein Prm1 and the nuclear membrane fusion protein Kar5 in both Cryptococcus species, and demonstrated their conserved roles in cell fusion and karyogamy during C. deneoformans α-α unisexual reproduction and C. deneoformans and C. neoformans a-α bisexual reproduction. Notably, karyogamy occurs inside the basidum during bisexual reproduction in C. neoformans, but often occurs earlier following cell fusion during bisexual reproduction in C. deneoformans. Characterization of these two genes also showed that cell fusion is dispensable for solo unisexual reproduction in C. deneoformans. The blastospores produced along hyphae during C. deneoformans unisexual reproduction are diploid, suggesting that diploidization occurs early during hyphal development, possibly through either an endoreplication pathway or cell fusion-independent karyogamy

Social transfer of pathogenic fungus promotes active immunisation in ant colonies.

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Matthias Konrad

Full Text Available Due to the omnipresent risk of epidemics, insect societies have evolved sophisticated disease defences at the individual and colony level. An intriguing yet little understood phenomenon is that social contact to pathogen-exposed individuals reduces susceptibility of previously naive nestmates to this pathogen. We tested whether such social immunisation in Lasius ants against the entomopathogenic fungus Metarhizium anisopliae is based on active upregulation of the immune system of nestmates following contact to an infectious individual or passive protection via transfer of immune effectors among group members--that is, active versus passive immunisation. We found no evidence for involvement of passive immunisation via transfer of antimicrobials among colony members. Instead, intensive allogrooming behaviour between naive and pathogen-exposed ants before fungal conidia firmly attached to their cuticle suggested passage of the pathogen from the exposed individuals to their nestmates. By tracing fluorescence-labelled conidia we indeed detected frequent pathogen transfer to the nestmates, where they caused low-level infections as revealed by growth of small numbers of fungal colony forming units from their dissected body content. These infections rarely led to death, but instead promoted an enhanced ability to inhibit fungal growth and an active upregulation of immune genes involved in antifungal defences (defensin and prophenoloxidase, PPO. Contrarily, there was no upregulation of the gene cathepsin L, which is associated with antibacterial and antiviral defences, and we found no increased antibacterial activity of nestmates of fungus-exposed ants. This indicates that social immunisation after fungal exposure is specific, similar to recent findings for individual-level immune priming in invertebrates. Epidemiological modeling further suggests that active social immunisation is adaptive, as it leads to faster elimination of the disease and lower

alpha AD alpha hybrids of Cryptococcus neoformans: evidence of same-sex mating in nature and hybrid fitness.

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Xiaorong Lin

2007-10-01

Full Text Available 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, alpha and a. However, the overwhelming predominance of mating type (MAT alpha over a in C. neoformans populations limits alpha-a mating in nature. Recently it was discovered that C. neoformans can undergo same-sex mating under laboratory conditions, especially between alpha isolates. Whether same-sex mating occurs in nature and contributes to the current population structure was unknown. In this study, natural alpha AD alpha hybrids that arose by fusion between two alpha 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 SXI1 alpha was also identified as a genetic factor likely involved in this process. In addition, laboratory-constructed alpha AD alpha 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.

Comparative Genomics of a Plant-Pathogenic Fungus, Pyrenophora tritici-repentis, Reveals Transduplication and the Impact of Repeat Elements on Pathogenicity and Population Divergence

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Manning, Viola A.; Pandelova, Iovanna; Dhillon, Braham; Wilhelm, Larry J.; Goodwin, Stephen B.; Berlin, Aaron M.; Figueroa, Melania; Freitag, Michael; Hane, James K.; Henrissat, Bernard; Holman, Wade H.; Kodira, Chinnappa D.; Martin, Joel; Oliver, Richard P.; Robbertse, Barbara; Schackwitz, Wendy; Schwartz, David C.; Spatafora, Joseph W.; Turgeon, B. Gillian; Yandava, Chandri; Young, Sarah; Zhou, Shiguo; Zeng, Qiandong; Grigoriev, Igor V.; Ma, Li-Jun; Ciuffetti, Lynda M.

2012-08-16

Pyrenophora tritici-repentis is a necrotrophic fungus causal to the disease tan spot of wheat, whose contribution to crop loss has increased significantly during the last few decades. Pathogenicity by this fungus is attributed to the production of host-selective toxins (HST), which are recognized by their host in a genotype-specific manner. To better understand the mechanisms that have led to the increase in disease incidence related to this pathogen, we sequenced the genomes of three P. tritici-repentis isolates. A pathogenic isolate that produces two known HSTs was used to assemble a reference nuclear genome of approximately 40 Mb composed of 11 chromosomes that encode 12,141 predicted genes. Comparison of the reference genome with those of a pathogenic isolate that produces a third HST, and a nonpathogenic isolate, showed the nonpathogen genome to be more diverged than those of the two pathogens. Examination of gene-coding regions has provided candidate pathogen-specific proteins and revealed gene families that may play a role in a necrotrophic lifestyle. Analysis of transposable elements suggests that their presence in the genome of pathogenic isolates contributes to the creation of novel genes, effector diversification, possible horizontal gene transfer events, identified copy number variation, and the first example of transduplication by DNA transposable elements in fungi. Overall, comparative analysis of these genomes provides evidence that pathogenicity in this species arose through an influx of transposable elements, which created a genetically flexible landscape that can easily respond to environmental changes.

Mechanisms of Surface Antigenic Variation in the Human Pathogenic Fungus Pneumocystis jirovecii.

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Schmid-Siegert, Emanuel; Richard, Sophie; Luraschi, Amanda; Mühlethaler, Konrad; Pagni, Marco; Hauser, Philippe M

2017-11-07

Microbial pathogens commonly escape the human immune system by varying surface proteins. We investigated the mechanisms used for that purpose by Pneumocystis jirovecii This uncultivable fungus is an obligate pulmonary pathogen that in immunocompromised individuals causes pneumonia, a major life-threatening infection. Long-read PacBio sequencing was used to assemble a core of subtelomeres of a single P. jirovecii strain from a bronchoalveolar lavage fluid specimen from a single patient. A total of 113 genes encoding surface proteins were identified, including 28 pseudogenes. These genes formed a subtelomeric gene superfamily, which included five families encoding adhesive glycosylphosphatidylinositol (GPI)-anchored glycoproteins and one family encoding excreted glycoproteins. Numerical analyses suggested that diversification of the glycoproteins relies on mosaic genes created by ectopic recombination and occurs only within each family. DNA motifs suggested that all genes are expressed independently, except those of the family encoding the most abundant surface glycoproteins, which are subject to mutually exclusive expression. PCR analyses showed that exchange of the expressed gene of the latter family occurs frequently, possibly favored by the location of the genes proximal to the telomere because this allows concomitant telomere exchange. Our observations suggest that (i) the P. jirovecii cell surface is made of a complex mixture of different surface proteins, with a majority of a single isoform of the most abundant glycoprotein, (ii) genetic mosaicism within each family ensures variation of the glycoproteins, and (iii) the strategy of the fungus consists of the continuous production of new subpopulations composed of cells that are antigenically different. IMPORTANCE Pneumocystis jirovecii is a fungus causing severe pneumonia in immunocompromised individuals. It is the second most frequent life-threatening invasive fungal infection. We have studied the mechanisms

Structures of a putative ζ-class glutathione S-transferase from the pathogenic fungus Coccidioides immitis

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Edwards, Thomas E.; Bryan, Cassie M.; Leibly, David J.; Dieterich, Shellie H.; Abendroth, Jan; Sankaran, Banumathi; Sivam, Dhileep; Staker, Bart L.; Van Voorhis, Wesley C.; Myler, Peter J.; Stewart, Lance J.

2011-01-01

The pathogenic fungus C. immitis causes coccidioidomycosis, a potentially fatal disease. Here, apo and glutathione-bound crystal structures of a previously uncharacterized protein from C. immitis that appears to be a ζ-class glutathione S-transferase are presented. Coccidioides immitis is a pathogenic fungus populating the southwestern United States and is a causative agent of coccidioidomycosis, sometimes referred to as Valley Fever. Although the genome of this fungus has been sequenced, many operons are not properly annotated. Crystal structures are presented for a putative uncharacterized protein that shares sequence similarity with ζ-class glutathione S-transferases (GSTs) in both apo and glutathione-bound forms. The apo structure reveals a nonsymmetric homodimer with each protomer comprising two subdomains: a C-terminal helical domain and an N-terminal thioredoxin-like domain that is common to all GSTs. Half-site binding is observed in the glutathione-bound form. Considerable movement of some components of the active site relative to the glutathione-free form was observed, indicating an induced-fit mechanism for cofactor binding. The sequence homology, structure and half-site occupancy imply that the protein is a ζ-class glutathione S-transferase, a maleylacetoacetate isomerase (MAAI)

Protein profiling of the dimorphic, pathogenic fungus, Penicillium marneffei

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Rundle William T

2008-06-01

Full Text Available Abstract Background Penicillium marneffei is a pathogenic fungus that afflicts immunocompromised individuals having lived or traveled in Southeast Asia. This species is unique in that it is the only dimorphic member of the genus. Dimorphism results from a process, termed phase transition, which is regulated by temperature of incubation. At room temperature, the fungus grows filamentously (mould phase, but at body temperature (37°C, a uninucleate yeast form develops that reproduces by fission. Formation of the yeast phase appears to be a requisite for pathogenicity. To date, no genes have been identified in P. marneffei that strictly induce mould-to-yeast phase conversion. In an effort to help identify potential gene products associated with morphogenesis, protein profiles were generated from the yeast and mould phases of P. marneffei. Results Whole cell proteins from the early stages of mould and yeast development in P. marneffei were resolved by two-dimensional gel electrophoresis. Selected proteins were recovered and sequenced by capillary-liquid chromatography-nanospray tandem mass spectrometry. Putative identifications were derived by searching available databases for homologous fungal sequences. Proteins found common to both mould and yeast phases included the signal transduction proteins cyclophilin and a RACK1-like ortholog, as well as those related to general metabolism, energy production, and protection from oxygen radicals. Many of the mould-specific proteins identified possessed similar functions. By comparison, proteins exhibiting increased expression during development of the parasitic yeast phase comprised those involved in heat-shock responses, general metabolism, and cell-wall biosynthesis, as well as a small GTPase that regulates nuclear membrane transport and mitotic processes in fungi. The cognate gene encoding the latter protein, designated RanA, was subsequently cloned and characterized. The P. marneffei RanA protein

Diversity of the Cryptococcus neoformans-Cryptococcus gattii species complex.

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Bovers, M.; Hagen, F.; Boekhout, T.

2008-01-01

More than 110 years of study of the Cryptococcus neoformans and Cryptococcus gattii species complex has resulted in an enormous accumulation of fundamental and applied biological and clinical knowledge. Recent developments in our understanding of the diversity within the species complex are

Sterylglucoside catabolism in Cryptococcus neoformans with endoglycoceramidase-related protein 2 (EGCrP2), the first steryl-β-glucosidase identified in fungi.

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Watanabe, Takashi; Ito, Tomoharu; Goda, Hatsumi M; Ishibashi, Yohei; Miyamoto, Tomofumi; Ikeda, Kazutaka; Taguchi, Ryo; Okino, Nozomu; Ito, Makoto

2015-01-09

Cryptococcosis is an infectious disease caused by pathogenic fungi, such as Cryptococcus neoformans and Cryptococcus gattii. The ceramide structure (methyl-d18:2/h18:0) of C. neoformans glucosylceramide (GlcCer) is characteristic and strongly related to its pathogenicity. We recently identified endoglycoceramidase-related protein 1 (EGCrP1) as a glucocerebrosidase in C. neoformans and showed that it was involved in the quality control of GlcCer by eliminating immature GlcCer during the synthesis of GlcCer (Ishibashi, Y., Ikeda, K., Sakaguchi, K., Okino, N., Taguchi, R., and Ito, M. (2012) Quality control of fungus-specific glucosylceramide in Cryptococcus neoformans by endoglycoceramidase-related protein 1 (EGCrP1). J. Biol. Chem. 287, 368-381). We herein identified and characterized EGCrP2, a homologue of EGCrP1, as the enzyme responsible for sterylglucoside catabolism in C. neoformans. In contrast to EGCrP1, which is specific to GlcCer, EGCrP2 hydrolyzed various β-glucosides, including GlcCer, cholesteryl-β-glucoside, ergosteryl-β-glucoside, sitosteryl-β-glucoside, and para-nitrophenyl-β-glucoside, but not α-glucosides or β-galactosides, under acidic conditions. Disruption of the EGCrP2 gene (egcrp2) resulted in the accumulation of a glycolipid, the structure of which was determined following purification to ergosteryl-3β-glucoside, a major sterylglucoside in fungi, by mass spectrometric and two-dimensional nuclear magnetic resonance analyses. This glycolipid accumulated in vacuoles and EGCrP2 was detected in vacuole-enriched fraction. These results indicated that EGCrP2 was involved in the catabolism of ergosteryl-β-glucoside in the vacuoles of C. neoformans. Distinct growth arrest, a dysfunction in cell budding, and an abnormal vacuole morphology were detected in the egcrp2-disrupted mutants, suggesting that EGCrP2 may be a promising target for anti-cryptococcal drugs. EGCrP2, classified into glycohydrolase family 5, is the first steryl

Pathogenicity of entomopathogenic fungus Metarhizium anisopliae (Deuteromycetes) to Ixodes scapularis (Acari: Ixodidae)

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Zhioua, E.; Browning, M.; Johnson, P.W.; Ginsberg, H.S.; LeBrun, R.A.

1997-01-01

The entomopathogenic fungus Metarhizium anisopliae is highly pathogenic to the black-legged tick, Ixodes scapularis. Spore concentrations of 108/ml for engorged larvae and 107/ml for engorged females resulted in 100% tick mortality, 2 wk post-infection. The LC50 value for engorged larvae (concentration to kill 50% of ticks) was 107 spores/ml. Metarhizium anisopliae shows considerable potential as a microbial control agent for the management of Ixodes scapularis.

Characterization of pathogenic races of the sugarcane smut fungus by neutron activation analysis

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Amire, O.A.; Schmitt, R.A.; Trione, E.J.

1982-01-01

Representative samples of five major races of Ustilago scitaminea, the causal organism of the smut disease of sugarcane, were obtained from infected sugarcane fields in the Western hemisphere. The variations in concentration of 10 elements (Na, Mg, Al, Cl, K, Ca, Mn, Fe, Co, and Zn) in the sporidial yeast-like cells of this fungal pathogen were analyzed by neutron activation analysis. Comparative analysis of the elemental compositions in the different races of the fungus showed that the five pathogenic races of Ustilago scitaminea may be distinguished from each other on the basis of elemental compositions. (author)

Pandora formicae, a specialist ant pathogenic fungus: New insights into biology and taxonomy.

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Małagocka, Joanna; Jensen, Annette Bruun; Eilenberg, Jørgen

2017-02-01

Among fungi from the order Entomophthorales (Entomophthoromycota), there are many specialized, obligatory insect-killing pathogens. Pandora formicae (Humber & Bałazy) Humber is a rare example of an entomophthoralean fungus adapted to exclusively infect social insects: wood ants from the genus Formica. There is limited information available on P. formicae; many important aspects of this host-pathogen system remain hitherto unknown, and the taxonomical status of the fungus is unclear. Our study fills out some main gaps in the life history of P. formicae, such as seasonal prevalence and overwintering strategy. Field studies of infection prevalence show a disease peak in late summer and early autumn. Typical thick-walled entomophthoralean resting spores of P. formicae are documented and described for the first time. The proportion of cadavers with resting spores increased from late summer throughout autumn, suggesting that these spores are the main overwintering fungal structures. In addition, the phylogenetic status of Pandora formicae is outlined. Finally, we review the available taxonomical literature and conclude that the name P. formicae should be used rather than the name P. myrmecophaga for ant-infecting fungi displaying described morphological features. Copyright © 2016 Elsevier Inc. All rights reserved.

Genome sequence of a microbial lipid producing fungus Cryptococcus albidus NT2002.

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Yong, Xiaoyu; Yan, Zhiying; Xu, Lin; Zhou, Jun; Wu, Xiayuan; Wu, Yuandong; Li, Yang; Chen, Zugeng; Zhou, Hua; Wei, Ping; Jia, Honghua

2016-04-10

Cryptococcus albidus NT2002, isolated from the soil in Xinjiang, China, appeared to have the ability to accumulate microbial lipid by utilizing various carbon sources. The predominant properties make it as a potential bio-platform for biodiesel production. Here, we report the complete genome sequence of C. albidus NT2002, which might provide a basis for further elucidation of the genetic background of this promising strain for developing metabolic engineering strategies to produce biodiesel in a green and sustainable manner. Copyright © 2016 Elsevier B.V. All rights reserved.

Biotransformation of alpha-bulnesene using a plant pathogenic fungus, Glomerella cingulata as a biocatalyst.

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Miyazawa, Mitsuo; Sugawara, Atsushi

2005-02-01

The biotransformation of a sesquiterpene having a guaiane skeleton, namely (+)-alpha-bulnesene was investigated using the plant pathogenic fungus, Glomerella cingulata as a biocatalyst. (+)-alpha-Bulnesene was oxidized at the double bond of the isopropenyl group and hydroxylated at the allylic methyl group to (4S,5S,7R)-1(10)-guaien-11,13,15-triol.

Asociacion de leveduras del genero Cryptococcus con especies de Eucalyptus en Santafe de Bogota Isolation of Cryptococcus sp. associated with Eucalyptus trees in Santafé de Bogota

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A. Duarte

1994-04-01

Full Text Available El aislamiento de Cryptococcus neoformans var. gattii, serotipo B, a partir del medio ambiente se estableció inicialmente en Australia en 1989, en asocio con el Eucalyptus camaldulensis y posteriormente con E. tereticornis. Con estos hallazgos se postuló que desde allí, el hongo se ha podido exportar, por medio de las semillas contaminadas, a otras regiones geográficas, incluyendo Colombia. El objetivo de éste estudio fue identificar las levaduras del género Cryptococcus asociadas con especies de Eucalyptus sp., como primera evaluación en la ecología de C. neoformans var. gattii en nuestro país. Se realizó en Santafé de Bogotá, con una población de 100 árboles ubicados al centro, nororiente, oriente y occidente de la ciudad, recolectando de cada uno de ellos flores, frutos, hojas, cortezas y detritos; el procesamiento de las muestras incluyó extracción del material con una solución salina con antibióticos, siembra en medios selectivos e identificación de las especies con base en las características morfológicas, macro y microscópicas y bioquímicas. Se aislaron 27 cepas de Cryptococcus pertenecientes a 9 especies de Cryptococcus, a partir de 21 árboles ubicados en 5 zonas diferentes de la ciudad. Se aisló C. neoformans y se identificó como C. neoformans var. neoformans serotipo A. Estos datos iniciales son importantes como primera evaluación de la asociación de Cryptococcus sp. con los Eucalyptus en nuestro país.Environmental isolation of Cryptococcus neoformans var. gattii was first made in Australia in 1989 by ELLIS. He established a specific association with the tree species Eucalyptus camaldulensis and E. tereticornis. Based on his findings, ELLIS proposed that the fungus could be exported from Australia to others regions, including Colombia, by means of infected seeds. The purpose of this study was to isolate and identify Cryptococcus sp., associated with Eucalyptus trees; this is the first ecological evaluation

Pleiotropic effects of deubiquitinating enzyme Ubp5 on growth and pathogenesis of Cryptococcus neoformans.

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Wei Fang

Full Text Available Ubiquitination is a reversible protein modification that influences various cellular processes in eukaryotic cells. Deubiquitinating enzymes remove ubiquitin, maintain ubiquitin homeostasis and regulate protein degradation via the ubiquitination pathway. Cryptococcus neoformans is an important basidiomycete pathogen that causes life-threatening meningoencephalitis primarily in the immunocompromised population. In order to understand the possible influence deubiquitinases have on growth and virulence of the model pathogenic yeast Cryptococcus neoformans, we generated deletion mutants of seven putative deubiquitinase genes. Compared to other deubiquitinating enzyme mutants, a ubp5Δ mutant exhibited severely attenuated virulence and many distinct phenotypes, including decreased capsule formation, hypomelanization, defective sporulation, and elevated sensitivity to several external stressors (such as high temperature, oxidative and nitrosative stresses, high salts, and antifungal agents. Ubp5 is likely the major deubiquitinating enzyme for stress responses in C. neoformans, which further delineates the evolutionary divergence of Cryptococcus from the model yeast S. cerevisiae, and provides an important paradigm for understanding the potential role of deubiquitination in virulence by other pathogenic fungi. Other putative deubiquitinase mutants (doa4Δ and ubp13Δ share some phenotypes with the ubp5Δ mutant, illustrating functional overlap among deubiquitinating enzymes in C. neoformans. Therefore, deubiquitinating enzymes (especially Ubp5 are essential for the virulence composite of C. neoformans and provide an additional yeast survival and propagation advantage in the host.

Mitochondrial DNA inheritance in the human fungal pathogen Cryptococcus gattii.

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Wang, Zixuan; Wilson, Amanda; Xu, Jianping

2015-02-01

The inheritance of mitochondrial DNA (mtDNA) is predominantly uniparental in most sexual eukaryotes. In this study, we examined the mitochondrial inheritance pattern of Cryptococcus gattii, a basidiomycetous yeast responsible for the recent and ongoing outbreak of cryptococcal infections in the US Pacific Northwest and British Columbia (especially Vancouver Island) in Canada. Using molecular markers, we analyzed the inheritance of mtDNA in 14 crosses between strains within and between divergent lineages in C. gattii. Consistent with results from recent studies, our analyses identified significant variations in mtDNA inheritance patterns among strains and crosses, ranging from strictly uniparental to biparental. For two of the crosses that showed uniparental mitochondrial inheritance in standard laboratory conditions, we further investigated the effects of the following environmental variables on mtDNA inheritance: UV exposure, temperature, and treatments with the methylation inhibitor 5-aza-2'-deoxycytidine and with the ubiquitination inhibitor ammonium chloride. Interestingly, one of these crosses showed no response to these environmental variables while the other exhibited diverse patterns ranging from complete uniparental inheritance of the MATa parent mtDNA, to biparental inheritance, and to a significant bias toward inheritance of the MATα parental mtDNA. Our results indicate that mtDNA inheritance in C. gattii differs from that in its closely related species Cryptococcus neoformans. Copyright © 2015 Elsevier Inc. All rights reserved.

Genes under positive selection in a model plant pathogenic fungus, Botrytis.

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Aguileta, Gabriela; Lengelle, Juliette; Chiapello, Hélène; Giraud, Tatiana; Viaud, Muriel; Fournier, Elisabeth; Rodolphe, François; Marthey, Sylvain; Ducasse, Aurélie; Gendrault, Annie; Poulain, Julie; Wincker, Patrick; Gout, Lilian

2012-07-01

The rapid evolution of particular genes is essential for the adaptation of pathogens to new hosts and new environments. Powerful methods have been developed for detecting targets of selection in the genome. Here we used divergence data to compare genes among four closely related fungal pathogens adapted to different hosts to elucidate the functions putatively involved in adaptive processes. For this goal, ESTs were sequenced in the specialist fungal pathogens Botrytis tulipae and Botrytis ficariarum, and compared with genome sequences of Botrytis cinerea and Sclerotinia sclerotiorum, responsible for diseases on over 200 plant species. A maximum likelihood-based analysis of 642 predicted orthologs detected 21 genes showing footprints of positive selection. These results were validated by resequencing nine of these genes in additional Botrytis species, showing they have also been rapidly evolving in other related species. Twenty of the 21 genes had not previously been identified as pathogenicity factors in B. cinerea, but some had functions related to plant-fungus interactions. The putative functions were involved in respiratory and energy metabolism, protein and RNA metabolism, signal transduction or virulence, similarly to what was detected in previous studies using the same approach in other pathogens. Mutants of B. cinerea were generated for four of these genes as a first attempt to elucidate their functions. Copyright © 2012 Elsevier B.V. All rights reserved.

Pigment Production on L-Tryptophan Medium by Cryptococcus gattii and Cryptococcus neoformans

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Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

2014-01-01

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin. PMID:24736553

Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

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Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

2014-01-01

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

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Stuart Chaskes

Full Text Available In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

Pathogenic and enzyme activities of the entomopathogenic fungus Tolypocladium cylindrosporum (Ascomycota: Hypocreales from Tierra del Fuego, Argentina

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Ana C Scorsetti

2012-06-01

Full Text Available Tolypocladium cylindrosporum is an entomopathogenic fungi that has been studied as a biological control agent against insects of several orders. The fungus has been isolated from the soil as well as from insects of the orders Coleoptera, Lepidoptera, Diptera and Hymenoptera. In this study, we analyzed the ability of a strain of T. cylindrosporum, isolated from soil samples taken in Tierra del Fuego, Argentina, to produce hydrolytic enzymes, and to study the relationship of those activities to the fungus pathogenicity against pest aphids. We have made the traditional and molecular characterization of this strain of T. cylindrosporum. The expression of hydrolase activity in the fungal strain was estimated at three incubation temperatures (4ºC, 12ºC and 24ºC, on different agar media supplemented with the following specific substrates: chitin azure, Tween ® 20, casein, and urea for chitinase, lipase, protease, and urease activity, respectively. The hydrolytic-enzyme activity was estimated qualitatively according to the presence of a halo of clarification through hydrolase action, besides was expressed semi-quantitatively as the ratio between the hydrolytic-halo and colony diameters. The pathogenicity of the fungus was tested on adults of the aphid Rhopalosiphum padi at three temperatures of incubation (4ºC, 12ºC and 24ºC. The suspension was adjusted to a concentration of 1x10 7 conidia/ml. In pathogenicity assays at seven days post-inoculation, the fungus caused the mortality of adults of Ropalosiphum padi at different temperatures also showed a broad ability to grow on several agar-culture media, supplemented with different carbon sources at the three incubation temperatures tested. Although, the growth was greater with higher incubation temperatures (with maximum levels at 24°C, the fungus reached similar colony diameters after 15 days of incubation on the medium supplemented with Tween® 20 at the lower two incubation temperatures of 4�

Pathogenic and enzyme activities of the entomopathogenic fungus Tolypocladium cylindrosporum (Ascomycota: Hypocreales) from Tierra del Fuego, Argentina.

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Scorsetti, Ana C; Elíades, Lorena A; Stenglein, Sebastián A; Cabello, Marta N; Pelizza, Sebastián A; Saparrat, Mario C N

2012-06-01

Tolypocladium cylindrosporum is an entomopathogenic fungi that has been studied as a biological control agent against insects of several orders. The fungus has been isolated from the soil as well as from insects of the orders Coleoptera, Lepidoptera, Diptera and Hymenoptera. In this study, we analyzed the ability of a strain of T cylindrosporum, isolated from soil samples taken in Tierra del Fuego, Argentina, to produce hydrolytic enzymes, and to study the relationship of those activities to the fungus pathogenicity against pest aphids. We have made the traditional and molecular characterization of this strain of T cylindrosporum. The expression of hydrolase activity in the fungal strain was estimated at three incubation temperatures (4 degreeC, 12 degreeC and 24 degreeC), on different agar media supplemented with the following specific substrates: chitin azure, Tween 20, casein, and urea for chitinase, lipase, protease, and urease activity, respectively. The hydrolytic-enzyme activity was estimated qualitatively according to the presence of a halo of clarification through hydrolase action, besides was expressed semi-quantitatively as the ratio between the hydrolytic-halo and colony diameters. The pathogenicity of the fungus was tested on adults of the aphid Rhopalosiphum padi at three temperatures of incubation (4 degree C, 12 degree C and 24 degree C). The suspension was adjusted to a concentration of 1x10(7) conidia/ml. In pathogenicity assays at seven days post-inoculation, the fungus caused the mortality of adults of Ropalosiphum padi at different temperatures also showed a broad ability to grow on several agar-culture media, supplemented with different carbon sources at the three incubation temperatures tested. Although, the growth was greater with higher incubation temperatures (with maximum levels at 24 degreeC), the fungus reached similar colony diameters after 15 days of incubation on the medium supplemented with Tween 20 at the lower two incubation

Cryptococcus neoformans: Tripping on Acid in the phagolysosome

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Carlos Miguel De Leon Rodriguez

2016-02-01

Full Text Available Cryptococcus neoformans (Cn is a basidiomycetous pathogenic yeast that is a frequent cause of meningoencephalitis in immunocompromised individuals. Cn is a facultative intracellular pathogen in mammals, insects and amoeba. Cn infection occurs after inhalation of spores or desiccated cells from the environment. After inhalation Cn localizes to the lungs where it can be phagocytosed by alveolar macrophages. Cn is surrounded by a polysaccharide capsule that helps the fungus survive in vivo by interfering with phagocytosis, quenching free radical bursts and shedding polysaccharides that negatively modulates the immune system. After phagocytosis, Cn resides within the phagosome that matures to become a phagolysosome, a process that results in the acidification of the phagolysosomal lumen. Cn replicates at a higher rate inside macrophages than in the extracellular environment, possibly as a result that the phagosomal pH is near that optimal for growth. Cn increases the phagolysosomal pH and modulates the dynamics of Rab GTPases interaction with the phagolysosome. Chemical manipulation of the phagolysosomal pH with drugs can result in direct and indirect killing of Cn and reduced non-lytic exocytosis. Phagolysosomal membrane damage after Cn infection occurs both in vivo and in vitro, and is required for Cn growth and survival. Macrophage treatment with IFN-γ reduces the phagolysosomal damage and increases intracellular killing of Cn. Studies on mice and humans show that treatment with IFN-γ can improve host control of the disease. However the mechanism by which Cn mediates phagolysosomal membrane damage remains unknown but likely candidates are phospholipases and mechanical damage from an enlarging capsule. Here we review Cn intracellular interaction with a particular emphasis on phagosomal interactions and develop the notion that the extent of damage of the phagosomal membrane is a key determinant of the outcome of the Cn-macrophage interaction.

Antifungal Activity Against Plant Pathogens of Metabolites from the Endophytic Fungus Cladosporium cladosporioides

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Wang, Xiaoning; Radwan, Mohamed M.; Taráwneh, Amer H.; Gao, Jiangtao; Wedge, David E.; Rosa, Luiz H.; Cutler, Horace G.; Cutler, Stephen J.

2013-01-01

Bioassay-guided fractionation of Cladosporium cladosporioides (Fresen.) de Vries extracts led to the isolation of four compounds, including cladosporin, 1, isocladosporin, 2, 5′-hydroxyasperentin, 3, and cladosporin-8-methyl ether, 4. An additional compound 5′,6-diacetyl cladosporin, 5, was synthesized by acetylation of compound 3. Compounds 1-5 were evaluated for antifungal activity against plant pathogens. Phomopsis viticola was the most sensitive fungus to the tested compounds. At 30 μM, c...

Calcineurin orchestrates dimorphic transitions, antifungal drug responses and host-pathogen interactions of the pathogenic mucoralean fungus Mucor circinelloides.

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Lee, Soo Chan; Li, Alicia; Calo, Silvia; Inoue, Makoto; Tonthat, Nam K; Bain, Judith M; Louw, Johanna; Shinohara, Mari L; Erwig, Lars P; Schumacher, Maria A; Ko, Dennis C; Heitman, Joseph

2015-09-01

Calcineurin plays essential roles in virulence and growth of pathogenic fungi and is a target of the natural products FK506 and Cyclosporine A. In the pathogenic mucoralean fungus Mucor circinelloides, calcineurin mutation or inhibition confers a yeast-locked phenotype indicating that calcineurin governs the dimorphic transition. Genetic analysis in this study reveals that two calcineurin A catalytic subunits (out of three) are functionally diverged. Homology modeling illustrates modes of resistance resulting from amino substitutions in the interface between each calcineurin subunit and the inhibitory drugs. In addition, we show how the dimorphic transition orchestrated by calcineurin programs different outcomes during host-pathogen interactions. For example, when macrophages phagocytose Mucor yeast, subsequent phagosomal maturation occurs, indicating host cells respond appropriately to control the pathogen. On the other hand, upon phagocytosis of spores, macrophages fail to form mature phagosomes. Cytokine production from immune cells differs following exposure to yeast versus spores (which germinate into hyphae). Thus, the morphogenic transition can be targeted as an efficient treatment option against Mucor infection. In addition, genetic analysis (including gene disruption and mutational studies) further strengthens the understanding of calcineurin and provides a foundation to develop antifungal agents targeting calcineurin to deploy against Mucor and other pathogenic fungi. © 2015 John Wiley & Sons Ltd.

Cryptococcus spp isolated from dust microhabitat in Brazilian libraries

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Leite Diniz P

2012-06-01

Full Text Available Abstract Background The Cryptococcus spp is currently composed of encapsulated yeasts of cosmopolitan distribution, including the etiological agents of cryptococcosis. The fungus are found mainly in substrates of animal and plant origin. Human infection occurs through inhalation of spores present in the environment. Methods Eighty-four swab collections were performed on dust found on books in three libraries in the city of Cuiabá, state of Mato Grosso, Brazil. The material was seeded in Sabouraud agar and then observed for characteristics compatible with colonies with a creamy to mucous aspect; the material was then isolated in birdseed (Niger agar and cultivated at a temperature of 37°C for 5 to 7 days. Identification of isolated colonies was performed by microscopic observation in fresh preparations dyed with India ink, additional tests performed on CGB (L-canavanine glycine bromothymol blue, urea broth, and carbohydrate assimilation tests (auxanogram. Results Of the 84 samples collected from book dust, 18 (21.4% were positive for Cryptococcus spp totalizing 41 UFC’s. The most frequently isolated species was C. gattii 15 (36.6%; followed by C. terreus, 12 (29.3%; C. luteolus 4 (9.8%; C. neoformans, and C. uniguttulatus 3 (7.3%, and C. albidus and C. humiculus with 2 (4.6% of the isolates. Conclusion The high biodiversity of the yeasts of the Cryptococcus genus, isolated from different environmental sources in urban areas of Brazil suggests the possibility of individuals whose immune systems have been compromised or even healthy individuals coming into sources of fungal propagules on a daily bases throughout their lives. This study demonstrates the acquisition possible of cryptococcosis infection from dust in libraries.

Cryptococcus spp isolated from dust microhabitat in Brazilian libraries.

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Leite, Diniz P; Amadio, Janaina V R S; Martins, Evelin R; Simões, Sara A A; Yamamoto, Ana Caroline A; Leal-Santos, Fábio A; Takahara, Doracilde T; Hahn, Rosane C

2012-06-08

The Cryptococcus spp is currently composed of encapsulated yeasts of cosmopolitan distribution, including the etiological agents of cryptococcosis. The fungus are found mainly in substrates of animal and plant origin. Human infection occurs through inhalation of spores present in the environment. Eighty-four swab collections were performed on dust found on books in three libraries in the city of Cuiabá, state of Mato Grosso, Brazil. The material was seeded in Sabouraud agar and then observed for characteristics compatible with colonies with a creamy to mucous aspect; the material was then isolated in birdseed (Niger) agar and cultivated at a temperature of 37°C for 5 to 7 days. Identification of isolated colonies was performed by microscopic observation in fresh preparations dyed with India ink, additional tests performed on CGB (L-canavanine glycine bromothymol blue), urea broth, and carbohydrate assimilation tests (auxanogram). Of the 84 samples collected from book dust, 18 (21.4%) were positive for Cryptococcus spp totalizing 41 UFC's. The most frequently isolated species was C. gattii 15 (36.6%); followed by C. terreus, 12 (29.3%); C. luteolus 4 (9.8%); C. neoformans, and C. uniguttulatus 3 (7.3%), and C. albidus and C. humiculus with 2 (4.6%) of the isolates. The high biodiversity of the yeasts of the Cryptococcus genus, isolated from different environmental sources in urban areas of Brazil suggests the possibility of individuals whose immune systems have been compromised or even healthy individuals coming into sources of fungal propagules on a daily bases throughout their lives. This study demonstrates the acquisition possible of cryptococcosis infection from dust in libraries.

Mechanisms of Pulmonary Escape and Dissemination by Cryptococcus neoformans

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Steven T. Denham

2018-02-01

Full Text Available Cryptococcus neoformans is a common environmental saprophyte and human fungal pathogen that primarily causes disease in immunocompromised individuals. Similar to many environmentally acquired human fungal pathogens, C. neoformans initiates infection in the lungs. However, the main driver of mortality is invasive cryptococcosis leading to fungal meningitis. After C. neoformans gains a foothold in the lungs, a critical early step in invasion is transversal of the respiratory epithelium. In this review, we summarize current knowledge relating to pulmonary escape. We focus on fungal factors that allow C. neoformans to disseminate from the lungs via intracellular and extracellular routes.

Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest

NARCIS (Netherlands)

Hagen, F.; Ceresini, P.C.; Polacheck, I.; Ma, H.; van Nieuwerburgh, F.; Gabaldon, T.; Kagan, S.; Pursall, E.R.; Hoogveld, H.L.; van Iersel, L.J.; Klau, G.W.; Kelk, S.M.; Stougie, L.; Bartlett, K.H.; Voelz, K.; Pryszcz, L.P.; Castaneda, E.; Lazera, M.; Meyer, W.; Deforce, D.; Meis, J.F.G.M.; May, R.C.; Klaassen, C.H.W.; Boekhout, T.

2013-01-01

Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause

Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest.

NARCIS (Netherlands)

Hagen, F.; Ceresini, P.C.; Polacheck, I.; Ma, H.; Nieuwerburgh, F. van; Gabaldón, T.; Kagan, S.; Pursall, E.R.; Hoogveld, H.L.; Iersel, L.J. van; Klau, G.W.; Kelk, S.M.; Stougie, L.; Bartlett, K.H.; Voelz, K.; Pryszcz, L.P.; Castañeda, E.; Lazera, M.; Meyer, W.; Deforce, D.; Meis, J.F.G.M.; May, R.C.; Klaassen, C.H.; Boekhout, T.

2013-01-01

Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause

Role of mannitol metabolism in the pathogenicity of the necrotrophic fungus Alternaria brassicicola

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Benoit eCalmes

2013-05-01

Full Text Available In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternaria brassicicola. Mannitol metabolism was examined during infection of Brassica oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e. a mannitol dehydrogenase (AbMdh, and a mannitol-1-phosphate dehydrogenase (AbMpd. Knockout mutants deficient for AbMdh or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behaviour were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicicola to efficiently accomplish key steps of its pathogenic life cycle.

Complement and innate immune evasion strategies of the human pathogenic fungus Candida albicans.

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Luo, Shanshan; Skerka, Christine; Kurzai, Oliver; Zipfel, Peter F

2013-12-15

Candida albicans is a medically important fungus that can cause a wide range of diseases ranging from superficial infections to disseminated disease, which manifests primarily in immuno-compromised individuals. Despite the currently applied anti-fungal therapies, both mortality and morbidity caused by this human pathogenic fungus are still unacceptably high. Therefore new prophylactic and therapeutic strategies are urgently needed to prevent fungal infection. In order to define new targets for combating fungal disease, there is a need to understand the immune evasion strategies of C. albicans in detail. In this review, we summarize different sophisticated immune evasion strategies that are utilized by C. albicans. The description of the molecular mechanisms used for immune evasion does on one hand help to understand the infection process, and on the other hand provides valuable information to define new strategies and diagnostic approaches to fight and interfere with Candida infections. Copyright © 2013 Elsevier Ltd. All rights reserved.

Two-dimensional proteome reference maps for the human pathogenic filamentous fungus Aspergillus fumigatus.

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Vödisch, Martin; Albrecht, Daniela; Lessing, Franziska; Schmidt, André D; Winkler, Robert; Guthke, Reinhard; Brakhage, Axel A; Kniemeyer, Olaf

2009-03-01

The filamentous fungus Aspergillus fumigatus has become the most important airborne fungal pathogen causing life-threatening infections in immunosuppressed patients. We established a 2-D reference map for A. fumigatus. Using MALDI-TOF-MS/MS, we identified 381 spots representing 334 proteins. Proteins involved in cellular metabolism, protein synthesis, transport processes and cell cycle were most abundant. Furthermore, we established a protocol for the isolation of mitochondria of A. fumigatus and developed a mitochondrial proteome reference map. 147 proteins represented by 234 spots were identified.

Isolation of Cryptococcus gattii from a Castanopsis argyrophylla tree hollow (Mai-Kaw), Chiang Mai, Thailand

NARCIS (Netherlands)

Khayhan, Kantarawee; Hagen, Ferry; Norkaew, Treepradab; Puengchan, Tanpalang; Boekhout, Teun; Sriburee, Pojana

2017-01-01

The pathogenic yeast Cryptococcus gattii was isolated from a tree hollow of a Castanopsis argyrophylla King ex Hook.f. (Fagaceae) in Chiang Mai, Thailand. Molecular characterization with amplified fragment length polymorphism analysis and multi-locus sequence typing showed that this isolate belonged

Draft whole genome sequence of groundnut stem rot fungus Athelia rolfsii revealing genetic architect of its pathogenicity and virulence.

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Iquebal, M A; Tomar, Rukam S; Parakhia, M V; Singla, Deepak; Jaiswal, Sarika; Rathod, V M; Padhiyar, S M; Kumar, Neeraj; Rai, Anil; Kumar, Dinesh

2017-07-13

Groundnut (Arachis hypogaea L.) is an important oil seed crop having major biotic constraint in production due to stem rot disease caused by fungus, Athelia rolfsii causing 25-80% loss in productivity. As chemical and biological combating strategies of this fungus are not very effective, thus genome sequencing can reveal virulence and pathogenicity related genes for better understanding of the host-parasite interaction. We report draft assembly of Athelia rolfsii genome of ~73 Mb having 8919 contigs. Annotation analysis revealed 16830 genes which are involved in fungicide resistance, virulence and pathogenicity along with putative effector and lethal genes. Secretome analysis revealed CAZY genes representing 1085 enzymatic genes, glycoside hydrolases, carbohydrate esterases, carbohydrate-binding modules, auxillary activities, glycosyl transferases and polysaccharide lyases. Repeat analysis revealed 11171 SSRs, LTR, GYPSY and COPIA elements. Comparative analysis with other existing ascomycotina genome predicted conserved domain family of WD40, CYP450, Pkinase and ABC transporter revealing insight of evolution of pathogenicity and virulence. This study would help in understanding pathogenicity and virulence at molecular level and development of new combating strategies. Such approach is imperative in endeavour of genome based solution in stem rot disease management leading to better productivity of groundnut crop in tropical region of world.

Draft genome of the fungus-growing termite pathogenic fungus Ophiocordyceps bispora (Ophiocordycipitaceae, Hypocreales, Ascomycota

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Benjamin H. Conlon

2017-04-01

Full Text Available This article documents the public availability of genome sequence data and assembled contigs representing the partial draft genome of Ophiocordyceps bispora. As one of the few known pathogens of fungus-farming termites, a draft genome of O. bispora represents the opportunity to further the understanding of disease and resistance in these complex termite societies. With the ongoing attempts to resolve the taxonomy of the Hypocralaean family, more genetic data will also help to shed light on the phylogenetic relationship between sexual and asexual life stages. Next generation sequence data is available from the European Nucleotide Archive (ENA under accession PRJEB13655; run numbers: ERR1368522, ERR1368523, and ERR1368524. Genome assembly available from ENA under accession numbers: FKNF01000001–FKNF01000302. Gene prediction available as protein fasta, nucleotide fasta and GFF file from Mendeley Data with accession doi:10.17632/r99fd6g3s4.2 (http://dx.doi.org/10.17632/r99fd6g3s4.2.

Characterization of the complete uric acid degradation pathway in the fungal pathogen Cryptococcus neoformans.

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I Russel Lee

Full Text Available Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase, URO2 (HIU hydrolase, URO3 (OHCU decarboxylase, DAL1 (allantoinase, DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein, and URE1 (urease. All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed.

Pathogenic fungus Batrachochytrium dendrobatidis in marbled water frog Telmatobius marmoratus: first record from Lake Titicaca, Bolivia.

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Cossel, John; Lindquist, Erik; Craig, Heather; Luthman, Kyle

2014-11-13

The pathogenic fungus Batrachochytrium dendrobatidis (Bd) has been associated with amphibian declines worldwide but has not been well-studied among Critically Endangered amphibian species in Bolivia. We sampled free-living marbled water frogs Telmatobius marmoratus (Anura: Leptodactylidae) from Isla del Sol, Bolivia, for Bd using skin swabs and quantitative polymerase chain reactions. We detected Bd on 44% of T. marmoratus sampled. This is the first record of Bd in amphibians from waters associated with Lake Titicaca, Bolivia. These results further confirm the presence of Bd in Bolivia and substantiate the potential threat of this pathogen to the Critically Endangered, sympatric Titicaca water frog T. culeus and other Andean amphibians.

Protein Composition of Infectious Spores Reveals Novel Sexual Development and Germination Factors in Cryptococcus.

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Mingwei Huang

2015-08-01

Full Text Available Spores are an essential cell type required for long-term survival across diverse organisms in the tree of life and are a hallmark of fungal reproduction, persistence, and dispersal. Among human fungal pathogens, spores are presumed infectious particles, but relatively little is known about this robust cell type. Here we used the meningitis-causing fungus Cryptococcus neoformans to determine the roles of spore-resident proteins in spore biology. Using highly sensitive nanoscale liquid chromatography/mass spectrometry, we compared the proteomes of spores and vegetative cells (yeast and identified eighteen proteins specifically enriched in spores. The genes encoding these proteins were deleted, and the resulting strains were evaluated for discernable phenotypes. We hypothesized that spore-enriched proteins would be preferentially involved in spore-specific processes such as dormancy, stress resistance, and germination. Surprisingly, however, the majority of the mutants harbored defects in sexual development, the process by which spores are formed. One mutant in the cohort was defective in the spore-specific process of germination, showing a delay specifically in the initiation of vegetative growth. Thus, by using this in-depth proteomics approach as a screening tool for cell type-specific proteins and combining it with molecular genetics, we successfully identified the first germination factor in C. neoformans. We also identified numerous proteins with previously unknown functions in both sexual development and spore composition. Our findings provide the first insights into the basic protein components of infectious spores and reveal unexpected molecular connections between infectious particle production and spore composition in a pathogenic eukaryote.

Identification of pathogenicity-related genes in the vascular wilt fungus verticillium dahliae by agrobacterium tumefaciens-mediated t-DNA insertional mutagenesis.

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Verticillium dahliae is the causal agent of vascular wilt in many economically important crops worldwide. Identification of genes that underpin pathogenicity or virulence may suggest targets for alternative control methods for this fungus. In this study, Agrobacterium tumefaciens-mediated transform...

Cryptosporidium,Giardia, Cryptococcus, Pneumocystis genetic variability: cryptic biological species or clonal near-clades?

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Michel Tibayrenc

2014-04-01

Full Text Available An abundant literature dealing with the population genetics and taxonomy of Giardia duodenalis, Cryptosporidium spp., Pneumocystis spp., and Cryptococcus spp., pathogens of high medical and veterinary relevance, has been produced in recent years. We have analyzed these data in the light of new population genetic concepts dealing with predominant clonal evolution (PCE recently proposed by us. In spite of the considerable phylogenetic diversity that exists among these pathogens, we have found striking similarities among them. The two main PCE features described by us, namely highly significant linkage disequilibrium and near-clading (stable phylogenetic clustering clouded by occasional recombination, are clearly observed in Cryptococcus and Giardia, and more limited indication of them is also present in Cryptosporidium and Pneumocystis. Moreover, in several cases, these features still obtain when the near-clades that subdivide the species are analyzed separately ("Russian doll pattern". Lastly, several sets of data undermine the notion that certain microbes form clonal lineages simply owing to a lack of opportunity to outcross due to low transmission rates leading to lack of multiclonal infections ("starving sex hypothesis". We propose that the divergent taxonomic and population genetic inferences advanced by various authors about these pathogens may not correspond to true evolutionary differences and could be, rather, the reflection of idiosyncratic practices among compartmentalized scientific communities. The PCE model provides an opportunity to revise the taxonomy and applied research dealing with these pathogens and others, such as viruses, bacteria, parasitic protozoa, and fungi.

Separate and Combined Effects of Mentha piperata and Mentha pulegium Essential Oils and a Pathogenic Fungus Lecanicillium muscarium Against Aphis gossypii (Hemiptera: Aphididae).

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Ebadollahi, Asgar; Davari, Mahdi; Razmjou, Jabrael; Naseri, Bahram

2017-06-01

In the present study, the toxicity of essential oils of Mentha piperata L. and Mentha pulegium L. and pathogenicity of Lecanicillium muscarium (Zare & Gams) were studied in the melon aphid, Aphis gossypii Glover. Analyses of the essential oils by GC-MS indicated limonene (27.28%), menthol (24.71%), menthone (14.01%), and carvol (8.46%) in the M. piperata essential oil and pulegone (73.44%), piperitenone (5.49%), decane (4.99%), and limonene (3.07%) in the essential oil of M. pulegium as the main components. Both essential oils and the pathogenic fungus had useful toxicity against A. gossypii. Probit analysis indicated LC50 values (lethal concentrations to kill 50% of population; 95% confidence limits in parentheses) of M. piperata and M. pulegium essential oils as 15.25 (12.25-19.56) and 23.13 (19.27-28.42) µl/liter air, respectively. Susceptibility to the pathogenic fungus increased with exposure time. Aphid mortality also increased when the essential oils were combined with L. muscarium, although the phenomena was additive rather than synergistic. Mycelial growth inhibition of L. muscarium exposed to the essential oils was also very low. Based on our results, M. piperata and M. pulegium essential oils and the pathogenic fungus L. muscarium have some potential for management of A. gossypii. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Chytrid fungus acts as a generalist pathogen infecting species-rich amphibian families in Brazilian rainforests.

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Valencia-Aguilar, Anyelet; Ruano-Fajardo, Gustavo; Lambertini, Carolina; da Silva Leite, Domingos; Toledo, Luís Felipe; Mott, Tamí

2015-05-11

The fungus Batrachochytrium dendrobatidis (Bd) is among the main causes of declines in amphibian populations. This fungus is considered a generalist pathogen because it infects several species and spreads rapidly in the wild. To date, Bd has been detected in more than 100 anuran species in Brazil, mostly in the southern portion of the Atlantic forest. Here, we report survey data from some poorly explored regions; these data considerably extend current information on the distribution of Bd in the northern Atlantic forest region. In addition, we tested the hypothesis that Bd is a generalist pathogen in this biome. We also report the first positive record for Bd in an anuran caught in the wild in Amazonia. In total, we screened 90 individuals (from 27 species), of which 39 individuals (from 22 species) were Bd-positive. All samples collected in Bahia (2 individuals), Pernambuco (3 individuals), Pará (1 individual), and Minas Gerais (1 individual) showed positive results for Bd. We found a positive correlation between anuran richness per family and the number of infected species in the Atlantic forest, supporting previous observations that Bd lacks strong host specificity; of 38% of the anuran species in the Atlantic forest that were tested for Bd infection, 25% showed positive results. The results of our study exemplify the pandemic and widespread nature of Bd infection in amphibians.

The Role of Ceramide Synthases in the Pathogenicity of Cryptococcus neoformans.

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Munshi, Mansa A; Gardin, Justin M; Singh, Ashutosh; Luberto, Chiara; Rieger, Robert; Bouklas, Tejas; Fries, Bettina C; Del Poeta, Maurizio

2018-02-06

Cryptococcus neoformans (C. neoformans) is estimated to cause about 220,000 new cases every year in patients with AIDS, despite advances in antifungal treatments. C. neoformans possesses a remarkable ability to disseminate through an immunocompromised host, making treatment difficult. Here, we examine the mechanism of survival of C. neoformans under varying host conditions and find a role for ceramide synthase in C. neoformans virulence. This study also provides a detailed lipidomics resource for the fungal lipid research community in addition to discovering a potential target for antifungal therapy. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

White-nose syndrome fungus: a generalist pathogen of hibernating bats.

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Jan Zukal

Full Text Available Host traits and phylogeny can determine infection risk by driving pathogen transmission and its ability to infect new hosts. Predicting such risks is critical when designing disease mitigation strategies, and especially as regards wildlife, where intensive management is often advocated or prevented by economic and/or practical reasons. We investigated Pseudogymnoascus [Geomyces] destructans infection, the cause of white-nose syndrome (WNS, in relation to chiropteran ecology, behaviour and phylogenetics. While this fungus has caused devastating declines in North American bat populations, there have been no apparent population changes attributable to the disease in Europe. We screened 276 bats of 15 species from hibernacula in the Czech Republic over 2012 and 2013, and provided histopathological evidence for 11 European species positive for WNS. With the exception of Myotis myotis, the other ten species are all new reports for WNS in Europe. Of these, M. emarginatus, Eptesicus nilssonii, Rhinolophus hipposideros, Barbastella barbastellus and Plecotus auritus are new to the list of P. destructans-infected bat species. While the infected species are all statistically phylogenetically related, WNS affects bats from two suborders. These are ecologically diverse and adopt a wide range of hibernating strategies. Occurrence of WNS in distantly related bat species with diverse ecology suggests that the pathogen may be a generalist and that all bats hibernating within the distribution range of P. destructans may be at risk of infection.

White-nose syndrome fungus: a generalist pathogen of hibernating bats.

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Zukal, Jan; Bandouchova, Hana; Bartonicka, Tomas; Berkova, Hana; Brack, Virgil; Brichta, Jiri; Dolinay, Matej; Jaron, Kamil S; Kovacova, Veronika; Kovarik, Miroslav; Martínková, Natália; Ondracek, Karel; Rehak, Zdenek; Turner, Gregory G; Pikula, Jiri

2014-01-01

Host traits and phylogeny can determine infection risk by driving pathogen transmission and its ability to infect new hosts. Predicting such risks is critical when designing disease mitigation strategies, and especially as regards wildlife, where intensive management is often advocated or prevented by economic and/or practical reasons. We investigated Pseudogymnoascus [Geomyces] destructans infection, the cause of white-nose syndrome (WNS), in relation to chiropteran ecology, behaviour and phylogenetics. While this fungus has caused devastating declines in North American bat populations, there have been no apparent population changes attributable to the disease in Europe. We screened 276 bats of 15 species from hibernacula in the Czech Republic over 2012 and 2013, and provided histopathological evidence for 11 European species positive for WNS. With the exception of Myotis myotis, the other ten species are all new reports for WNS in Europe. Of these, M. emarginatus, Eptesicus nilssonii, Rhinolophus hipposideros, Barbastella barbastellus and Plecotus auritus are new to the list of P. destructans-infected bat species. While the infected species are all statistically phylogenetically related, WNS affects bats from two suborders. These are ecologically diverse and adopt a wide range of hibernating strategies. Occurrence of WNS in distantly related bat species with diverse ecology suggests that the pathogen may be a generalist and that all bats hibernating within the distribution range of P. destructans may be at risk of infection.

Identification of Cryptococcus neoformans isolates using Staib agar without creatinine

OpenAIRE

Nardelli, Vanessa; Pérez, Celina; Mata-Essayag, Sofía; Colella, María Teresa; Roselló, Arantza; Hartung de Capriles, Claudia; Landaeta, María Eugenia; Olaizola, Carolina; Magaldi, Sylvia

2005-01-01

In mycology, culture is the best way to demonstrate and identify pathogenic fungi. Many kinds of media have been developed and modified, using fungal biochemical properties to recognize them. The most common media are Sabouraud, Malt Agar, Cornmeal agar, Potato-dextrose agar, and Staib agar. Staib agar has been widely used for identification of yeasts from the genus Cryptococcus and other fungi. The aim of this study was to demonstrate the usefulness of Staib agar, and of a modified Staib med...

Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

Science.gov (United States)

Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

2016-10-01

Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Genomic insight into pathogenicity of dematiaceous fungus Corynespora cassiicola

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Hong Keat Looi

2017-01-01

Full Text Available Corynespora cassiicola is a common plant pathogen that causes leaf spot disease in a broad range of crop, and it heavily affect rubber trees in Malaysia (Hsueh, 2011; Nghia et al., 2008. The isolation of UM 591 from a patient’s contact lens indicates the pathogenic potential of this dematiaceous fungus in human. However, the underlying factors that contribute to the opportunistic cross-infection have not been fully studied. We employed genome sequencing and gene homology annotations in attempt to identify these factors in UM 591 using data obtained from publicly available bioinformatics databases. The assembly size of UM 591 genome is 41.8 Mbp, and a total of 13,531 (≥99 bp genes have been predicted. UM 591 is enriched with genes that encode for glycoside hydrolases, carbohydrate esterases, auxiliary activity enzymes and cell wall degrading enzymes. Virulent genes comprising of CAZymes, peptidases, and hypervirulence-associated cutinases were found to be present in the fungal genome. Comparative analysis result shows that UM 591 possesses higher number of carbohydrate esterases family 10 (CE10 CAZymes compared to other species of fungi in this study, and these enzymes hydrolyses wide range of carbohydrate and non-carbohydrate substrates. Putative melanin, siderophore, ent-kaurene, and lycopene biosynthesis gene clusters are predicted, and these gene clusters denote that UM 591 are capable of protecting itself from the UV and chemical stresses, allowing it to adapt to different environment. Putative sterigmatocystin, HC-toxin, cercosporin, and gliotoxin biosynthesis gene cluster are predicted. This finding have highlighted the necrotrophic and invasive nature of UM 591.

Agrobacterium tumefaciens-mediated transformation for investigating pathogenicity genes of the phytopathogenic fungus Colletotrichum sansevieriae.

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Nakamura, Masayuki; Kuwahara, Hideto; Onoyama, Keisuke; Iwai, Hisashi

2012-08-01

Agrobacterium tumefaciens-mediated transformation (AtMT) has become a common technique for DNA transformation of yeast and filamentous fungi. In this study, we first established a protocol of AtMT for the phytopathogenic fungus Colletotrichum sansevieriae. Binary T-DNA vector containing the hygromycin B phosphotransferase gene controlled by the Aspergillus nidulans gpdA promoter and the trpC terminator was constructed with pCAMBIA0380 and used with three different strains LBA4404, GV3101, and GV2260 of A. tumefaciens. Transformants were most effectively obtained when GV2260 and C. sansevieriae Sa-1-2 were co-cultivated; there were about 320 transformants per 10(6) spores. When 1,048 transformants were inoculated on Sansevieria trifasciata, three transformants were found to have completely lost their pathogenicity and two transformants displayed reduced pathogenicity. All of the five transformants had a single copy of T-DNA in their genomes. The three pathogenicity-deficient transformants were subjected to thermal asymmetric interlaced polymerase chain reaction and the reaction allowed us to amplify the sequences flanking the left and/or right borders. The flanking sequences of the two transformants, M154 and M875, showed no homology to any sequences in databases, but the sequences of M678 contained motifs of alpha-1,3-glucan synthase, suggesting that the gene might contribute to the pathogenicity of C. sansevieriae. This study describes a useful method for investigating pathogenicity genes in C. sansevieriae.

New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens

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H. M. T.Bandara Herath; Melissa Jacob; A. Alpus Wilson; Hamed K. Abbas; N.P. Dhammika Nanayakkara. Nanayakkara

2012-01-01

Ethyl acetate extracts of Armillaria tabescens (strain JNB-OZ344) showed significant fungistatic and bacteristatic activities against several major human pathogens including Candida albicans, Cryptococcus neoformans, Escherichia coli and Mycobacterium intracellulare. Chemical analysis of these extracts led to the isolation and identification of four new compounds,...

Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples

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Christian Alvarez

2013-02-01

Full Text Available In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA plates. The conventional technique (CT yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g-1] compared to the humid swab technique (ST. However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g-1, while the threshold for the ST was greater than 0.1.10³ CFU-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.

Volatile antimicrobials from Muscodor crispans, a novel endophytic fungus.

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Mitchell, Angela M; Strobel, Gary A; Moore, Emily; Robison, Richard; Sears, Joe

2010-01-01

Muscodor crispans is a recently described novel endophytic fungus of Ananas ananassoides (wild pineapple) growing in the Bolivian Amazon Basin. The fungus produces a mixture of volatile organic compounds (VOCs); some of the major components of this mixture, as determined by GC/MS, are propanoic acid, 2-methyl-, methyl ester; propanoic acid, 2-methyl-; 1-butanol, 3-methyl-;1-butanol, 3-methyl-, acetate; propanoic acid, 2-methyl-, 2-methylbutyl ester; and ethanol. The fungus does not, however, produce naphthalene or azulene derivatives as has been observed with many other members of the genus Muscodor. The mixture of VOCs produced by M. crispans cultures possesses antibiotic properties, as does an artificial mixture of a majority of the components. The VOCs of the fungus are effective against a wide range of plant pathogens, including the fungi Pythium ultimum, Phytophthora cinnamomi, Sclerotinia sclerotiorum and Mycosphaerella fijiensis (the black sigatoka pathogen of bananas), and the serious bacterial pathogen of citrus, Xanthomonas axonopodis pv. citri. In addition, the VOCs of M. crispans killed several human pathogens, including Yersinia pestis, Mycobacterium tuberculosis and Staphylococcus aureus. Artificial mixtures of the fungal VOCs were both inhibitory and lethal to a number of human and plant pathogens, including three drug-resistant strains of Mycobacterium tuberculosis. The gaseous products of Muscodor crispans potentially could prove to be beneficial in the fields of medicine, agriculture, and industry.

Effects of radiation type and delivery mode on a radioresistant eukaryote Cryptococcus neoformans

International Nuclear Information System (INIS)

Shuryak, Igor; Bryan, Ruth A.; Broitman, Jack; Marino, Stephen A.; Morgenstern, Alfred; Apostolidis, Christos; Dadachova, Ekaterina

2015-01-01

Introduction: Most research on radioresistant fungi, particularly on human pathogens such as Cryptococcus neoformans, involves sparsely-ionizing radiation. Consequently, fungal responses to densely-ionizing radiation, which can be harnessed to treat life-threatening fungal infections, remain incompletely understood. Methods: We addressed this issue by quantifying and comparing the effects of densely-ionizing α-particles (delivered either by external beam or by 213 Bi-labeled monoclonal antibodies), and sparsely-ionizing 137 Cs γ-rays, on Cryptococus neoformans. Results: The best-fit linear-quadratic parameters for clonogenic survival were the following: α = 0.24 × 10 −2 Gy −1 for γ-rays and 1.07 × 10 −2 Gy −1 for external-beam α-particles, and β = 1.44 × 10 −5 Gy −2 for both radiation types. Fungal cell killing by radiolabeled antibodies was consistent with predictions based on the α-particle dose to the cell nucleus and the linear-quadratic parameters for external-beam α-particles. The estimated RBE (for α-particles vs. γ-rays) at low doses was 4.47 for the initial portion of the α-particle track, and 7.66 for the Bragg peak. Non-radiological antibody effects accounted for up to 23% of cell death. Conclusions: These results quantify the degree of C. neoformans resistance to densely-ionizing radiations, and show how this resistance can be overcome with fungus-specific radiolabeled antibodies

Cryptococcus Neoformans: The First Reported Case of Isolation in Pigeon Excreta in the City of Votuporanga-São Paulo

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Cátia Rezende

2015-12-01

Full Text Available Cryptococcocus neoformans and Cryptococcus gattii are closely related pathogenic fungi that cause pneumonia and meningitis in both immunocompromised and immunocompetent hosts. Both species are found in the environment, and are acquired via inhalation, leading to an initial pulmonary infection. We evaluated 48 air samples and 32 samples of pigeon excreta from June to August, 2007. The presence of capsule was examined with Indian ink preparation. They were also tested for urease and phenoloxidase enzymes. Cryptococcus neoformans was recovered from pigeon excreta in 3.1%. The results suggest that climatic conditions can affect the occurrence of the yeast in different environmental sources.

Nitrogen Metabolite Repression of Metabolism and Virulence in the Human Fungal Pathogen Cryptococcus neoformans

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Lee, I. Russel; Chow, Eve W. L.; Morrow, Carl A.; Djordjevic, Julianne T.; Fraser, James A.

2011-01-01

Proper regulation of metabolism is essential to maximizing fitness of organisms in their chosen environmental niche. Nitrogen metabolite repression is an example of a regulatory mechanism in fungi that enables preferential utilization of easily assimilated nitrogen sources, such as ammonium, to conserve resources. Here we provide genetic, transcriptional, and phenotypic evidence of nitrogen metabolite repression in the human pathogen Cryptococcus neoformans. In addition to loss of transcriptional activation of catabolic enzyme-encoding genes of the uric acid and proline assimilation pathways in the presence of ammonium, nitrogen metabolite repression also regulates the production of the virulence determinants capsule and melanin. Since GATA transcription factors are known to play a key role in nitrogen metabolite repression, bioinformatic analyses of the C. neoformans genome were undertaken and seven predicted GATA-type genes were identified. A screen of these deletion mutants revealed GAT1, encoding the only global transcription factor essential for utilization of a wide range of nitrogen sources, including uric acid, urea, and creatinine—three predominant nitrogen constituents found in the C. neoformans ecological niche. In addition to its evolutionarily conserved role in mediating nitrogen metabolite repression and controlling the expression of catabolic enzyme and permease-encoding genes, Gat1 also negatively regulates virulence traits, including infectious basidiospore production, melanin formation, and growth at high body temperature (39°–40°). Conversely, Gat1 positively regulates capsule production. A murine inhalation model of cryptococcosis revealed that the gat1Δ mutant is slightly more virulent than wild type, indicating that Gat1 plays a complex regulatory role during infection. PMID:21441208

Effect of plant extracts and a disinfectant on biological parameters and pathogenicity of the fungus Beauveria bassiana (Bals. Vuill. (Ascomycota: Cordycipitaceae

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C. C. Martins

Full Text Available Abstract The fungus Beauveria bassiana is naturally found in poultry houses and causes high rates of mortality in Alphitobius diaperinus. Laboratory and field experiments have shown the potential of this fungus as an insect control agent. However, in poultry houses, bacteria as Salmonella, can be found and have been studied alternative control methods for this pathogen. Thus, this study aimed to evaluate the effect of plant extracts and a disinfectant on the fungus Beauveria bassiana (strain Unioeste 4. Conidial viability, colony-forming unit (CFU counts, vegetative growth, conidia production, insecticidal activity of the fungus and compatibility were used as parameters in the evaluation of the effect of these products on the fungus. Alcoholic and aqueous extracts of jabuticaba (Myrciaria cauliflora (Mart., guava (Psidium guajava (L., and jambolan (Syzygium cumini (L., at concentrations of 10% as well as the commercial disinfectant, Peroxitane® 1512 AL, were evaluated at the recommended concentrations (RC, 1:200 (RC, 0.5 RC and 2 RC. There was a negative influence of alcoholic and aqueous extracts of jabuticaba, guava and three dilutions of Peroxitane on the viability of conidia. The CFUs and vegetative growth of the fungus were affected only by the Peroxitane (all dilutions. For conidial production, the aqueous extract of guava had a positive effect, increasing production, while the Peroxitane at the R and RC concentrations resulted in a negative influence. The mortality of A. diaperinus, caused by the fungus after exposure to these products, was 60% for the peracetic acid at 0.5 RC, and above 80% for the extracts. Thus, the results showed that all the extracts and Peroxitane at RC 0.5 are compatible with the fungus B. bassiana Unioeste 4, however only the extracts had a low impact on inoculum potential.

The rhizosphere microbial community in a multiple parallel mineralization system suppresses the pathogenic fungus Fusarium oxysporum

Science.gov (United States)

Fujiwara, Kazuki; Iida, Yuichiro; Iwai, Takashi; Aoyama, Chihiro; Inukai, Ryuya; Ando, Akinori; Ogawa, Jun; Ohnishi, Jun; Terami, Fumihiro; Takano, Masao; Shinohara, Makoto

2013-01-01

The rhizosphere microbial community in a hydroponics system with multiple parallel mineralization (MPM) can potentially suppress root-borne diseases. This study focused on revealing the biological nature of the suppression against Fusarium wilt disease, which is caused by the fungus Fusarium oxysporum, and describing the factors that may influence the fungal pathogen in the MPM system. We demonstrated that the rhizosphere microbiota that developed in the MPM system could suppress Fusarium wilt disease under in vitro and greenhouse conditions. The microbiological characteristics of the MPM system were able to control the population dynamics of F. oxysporum, but did not eradicate the fungal pathogen. The roles of the microbiological agents underlying the disease suppression and the magnitude of the disease suppression in the MPM system appear to depend on the microbial density. F. oxysporum that survived in the MPM system formed chlamydospores when exposed to the rhizosphere microbiota. These results suggest that the microbiota suppresses proliferation of F. oxysporum by controlling the pathogen's morphogenesis and by developing an ecosystem that permits coexistence with F. oxysporum. PMID:24311557

Sterol composition of Cryptococcus neoformans in the presence and absence of fluconazole.

OpenAIRE

Ghannoum, M A; Spellberg, B J; Ibrahim, A S; Ritchie, J A; Currie, B; Spitzer, E D; Edwards, J E; Casadevall, A

1994-01-01

Analysis of the sterol compositions of 13 clinical isolates of the pathogenic yeast Cryptococcus neoformans obtained from five patients with recurring cryptococcal meningitis showed that, unlike Candida albicans, the major sterols synthesized by this yeast were obtusifoliol (range, 21.1 to 68.2%) and ergosterol (range, 0.0 to 46.5%). There was considerable variation in the sterol contents among the 13 isolates, with total sterol contents ranging from 0.31 to 5.9% of dry weight. The isolates f...

Pathogenic and enzyme activities of the entomopathogenic fungus Tolypocladium cylindrosporum (Ascomycota: Hypocreales from Tierra del Fuego, Argentina

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Ana C Scorsetti

2012-06-01

Full Text Available Tolypocladium cylindrosporum is an entomopathogenic fungi that has been studied as a biological control agent against insects of several orders. The fungus has been isolated from the soil as well as from insects of the orders Coleoptera, Lepidoptera, Diptera and Hymenoptera. In this study, we analyzed the ability of a strain of T. cylindrosporum, isolated from soil samples taken in Tierra del Fuego, Argentina, to produce hydrolytic enzymes, and to study the relationship of those activities to the fungus pathogenicity against pest aphids. We have made the traditional and molecular characterization of this strain of T. cylindrosporum. The expression of hydrolase activity in the fungal strain was estimated at three incubation temperatures (4ºC, 12ºC and 24ºC, on different agar media supplemented with the following specific substrates: chitin azure, Tween ® 20, casein, and urea for chitinase, lipase, protease, and urease activity, respectively. The hydrolytic-enzyme activity was estimated qualitatively according to the presence of a halo of clarification through hydrolase action, besides was expressed semi-quantitatively as the ratio between the hydrolytic-halo and colony diameters. The pathogenicity of the fungus was tested on adults of the aphid Rhopalosiphum padi at three temperatures of incubation (4ºC, 12ºC and 24ºC. The suspension was adjusted to a concentration of 1x10 7 conidia/ml. In pathogenicity assays at seven days post-inoculation, the fungus caused the mortality of adults of Ropalosiphum padi at different temperatures also showed a broad ability to grow on several agar-culture media, supplemented with different carbon sources at the three incubation temperatures tested. Although, the growth was greater with higher incubation temperatures (with maximum levels at 24°C, the fungus reached similar colony diameters after 15 days of incubation on the medium supplemented with Tween® 20 at the lower two incubation temperatures of 4�

In vitro anidulafungin activity against yeasts – system and disseminated mycosis pathogens

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A. B. Kulko

2015-01-01

Full Text Available We analyzed susceptibility to anidulafungin of yeasts clinical strains of Candida (14 species, Cryptococcus (1 species, Geotrichum (1 species, Rhodotorula (1 species and Saccharomyces (1 species. We revealed high anidulafungin activity against Candida spp., both common species and rare pathogens of candidiasis. It was found that over 99 % of Candida strains do not have an acquired resistance mechanisms to anidulafungin (microbiological criteria. The anidulafungin is not active against strains of Cryptococcus neoformans and Rhodotorula mucilaginosa.

The rhizosphere microbial community in a multiple parallel mineralization system suppresses the pathogenic fungus Fusarium oxysporum.

Science.gov (United States)

Fujiwara, Kazuki; Iida, Yuichiro; Iwai, Takashi; Aoyama, Chihiro; Inukai, Ryuya; Ando, Akinori; Ogawa, Jun; Ohnishi, Jun; Terami, Fumihiro; Takano, Masao; Shinohara, Makoto

2013-12-01

The rhizosphere microbial community in a hydroponics system with multiple parallel mineralization (MPM) can potentially suppress root-borne diseases. This study focused on revealing the biological nature of the suppression against Fusarium wilt disease, which is caused by the fungus Fusarium oxysporum, and describing the factors that may influence the fungal pathogen in the MPM system. We demonstrated that the rhizosphere microbiota that developed in the MPM system could suppress Fusarium wilt disease under in vitro and greenhouse conditions. The microbiological characteristics of the MPM system were able to control the population dynamics of F. oxysporum, but did not eradicate the fungal pathogen. The roles of the microbiological agents underlying the disease suppression and the magnitude of the disease suppression in the MPM system appear to depend on the microbial density. F. oxysporum that survived in the MPM system formed chlamydospores when exposed to the rhizosphere microbiota. These results suggest that the microbiota suppresses proliferation of F. oxysporum by controlling the pathogen's morphogenesis and by developing an ecosystem that permits coexistence with F. oxysporum. © 2013 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Interspecies differences in the enantioselectivity of epoxide hydrolases in Cryptococcus laurentii (Kufferath) C.E. Skinner and Cryptococcus podzolicus (Bab'jeva & Reshetova) Golubev

CSIR Research Space (South Africa)

Botes, AL

2005-01-01

Full Text Available Isolates representing Cryptococcus laurentii and Cryptococcus podzolicus, originating from soil of a heath land indigenous to South Africa, were screened for the presence of enantioselective epoxide hydrolases for 2, 2-disubstituted epoxides...

Pseudomonas aeruginosa inhibits the growth of Cryptococcus species.

Science.gov (United States)

Rella, Antonella; Yang, Mo Wei; Gruber, Jordon; Montagna, Maria Teresa; Luberto, Chiara; Zhang, Yong-Mei; Del Poeta, Maurizio

2012-06-01

Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.

Isolation of Cryptococcus gattii from a Castanopsis argyrophylla tree hollow (Mai-Kaw), Chiang Mai, Thailand.

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Khayhan, Kantarawee; Hagen, Ferry; Norkaew, Treepradab; Puengchan, Tanpalang; Boekhout, Teun; Sriburee, Pojana

2017-04-01

The pathogenic yeast Cryptococcus gattii was isolated from a tree hollow of a Castanopsis argyrophylla King ex Hook.f. (Fagaceae) in Chiang Mai, Thailand. Molecular characterization with amplified fragment length polymorphism analysis and multi-locus sequence typing showed that this isolate belonged to genotype AFLP4/VGI representing C. gattii sensu stricto. Subsequent comparison of the environmental isolate with those from clinical samples from Thailand showed that they grouped closely together in a single cluster.

[Preservation of high risk fungal cultures of Histoplasma and Cryptococcus].

Science.gov (United States)

Fernández Andreu, C Carlos Manuel; Díaz Suárez, Luis Alberto; Ilnait Zaragozi, María Teresa; Aragonés López, Carlos; Martínez Machín, Gerardo; Perurena Lancha, Mayda R

2012-01-01

culture collections are responsible for providing the microbial resources for development of biological sciences. Storage in distilled water is one of the easiest and least expensive method for long-term fungal preservation. to evaluate the usefulness of this preservation method in fungal culture of Histoplasma and Cryptococcus. the preservation condition of the highest biological risk species from Histoplasma y Cryptococcus genera, included in the fungal culture collection of "Pedro Kouri" Institute of Tropical Medicine in Havana, was evaluated in this study. One hundred and two strains stored in distilled water, 92% of which had been preserved for more than 10 years, were analyzed. the percentages of recovered strains from H. capsulatum, C. neoformans and C. gattii were 64.3%; 79.1% and 100% respectively. This method of preservation proved to be satisfactory for fungal culture in labs with limited financial resources. A web-based database with interesting information about the collection was made. The importance of strict compliance with the biosafety measures in these collections, particularly with high risk pathogens. preservation of fungal cultures in distilled water is a very useful method for laboratories with limited resources. Culture collections should be assumed as an essential activity in order to solve increasing challenges in the development of biomedical sciences.

Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival.

Science.gov (United States)

Al-Laaeiby, Ayat; Kershaw, Michael J; Penn, Tina J; Thornton, Christopher R

2016-03-24

The dematiaceous (melanised) fungus Lomentospora (Scedosporium) prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H₂O₂), UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN)-melanin biosynthetic enzymes polyketide synthase (PKS1), tetrahydroxynapthalene reductase (4HNR) and scytalone dehydratase (SCD1). Infectious propagules (spores) of the wild-type strain 3.1 were black/brown, whereas spores of the PKS-deficient mutant ΔLppks1::hph were white. Complementation of the albino mutant ΔLppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant ΔLp4hnr::hph and SCD-deficient mutant ΔLpscd1::hph both produced orange-yellow spores. The mutants ΔLppks1::hph and ΔLp4hnr::hph showed significant reductions in spore survival following H₂O₂ treatment, while spores of ΔLpscd1::hph and the ΔLppks1::hph complemented strain ΔLppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants ΔLp4hnr::hph and ΔLpscd1::hph and complemented strain ΔLppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of ΔLppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants ΔLp4hnr::hph and ΔLppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not

The mating type locus (MAT and sexual reproduction of Cryptococcus heveanensis: insights into the evolution of sex and sex-determining chromosomal regions in fungi.

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Banu Metin

2010-05-01

Full Text Available 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

Trojan Horse Transit Contributes to Blood-Brain Barrier Crossing of a Eukaryotic Pathogen.

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Santiago-Tirado, Felipe H; Onken, Michael D; Cooper, John A; Klein, Robyn S; Doering, Tamara L

2017-01-31

The blood-brain barrier (BBB) protects the central nervous system (CNS) by restricting the passage of molecules and microorganisms. Despite this barrier, however, the fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that is estimated to kill over 600,000 people annually. Cryptococcal infection begins in the lung, and experimental evidence suggests that host phagocytes play a role in subsequent dissemination, although this role remains ill defined. Additionally, the disparate experimental approaches that have been used to probe various potential routes of BBB transit make it impossible to assess their relative contributions, confounding any integrated understanding of cryptococcal brain entry. Here we used an in vitro model BBB to show that a "Trojan horse" mechanism contributes significantly to fungal barrier crossing and that host factors regulate this process independently of free fungal transit. We also, for the first time, directly imaged C. neoformans-containing phagocytes crossing the BBB, showing that they do so via transendothelial pores. Finally, we found that Trojan horse crossing enables CNS entry of fungal mutants that cannot otherwise traverse the BBB, and we demonstrate additional intercellular interactions that may contribute to brain entry. Our work elucidates the mechanism of cryptococcal brain invasion and offers approaches to study other neuropathogens. The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes

A link between virulence and homeostatic responses to hypoxia during infection by the human fungal pathogen Cryptococcus neoformans.

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Cheryl D Chun

2007-02-01

Full Text Available Fungal pathogens of humans require molecular oxygen for several essential biochemical reactions, yet virtually nothing is known about how they adapt to the relatively hypoxic environment of infected tissues. We isolated mutants defective in growth under hypoxic conditions, but normal for growth in normoxic conditions, in Cryptococcus neoformans, the most common cause of fungal meningitis. Two regulatory pathways were identified: one homologous to the mammalian sterol-response element binding protein (SREBP cholesterol biosynthesis regulatory pathway, and the other a two-component-like pathway involving a fungal-specific hybrid histidine kinase family member, Tco1. We show that cleavage of the SREBP precursor homolog Sre1-which is predicted to release its DNA-binding domain from the membrane-occurs in response to hypoxia, and that Sre1 is required for hypoxic induction of genes encoding for oxygen-dependent enzymes involved in ergosterol synthesis. Importantly, mutants in either the SREBP pathway or the Tco1 pathway display defects in their ability to proliferate in host tissues and to cause disease in infected mice, linking for the first time to our knowledge hypoxic adaptation and pathogenesis by a eukaryotic aerobe. SREBP pathway mutants were found to be a hundred times more sensitive than wild-type to fluconazole, a widely used antifungal agent that inhibits ergosterol synthesis, suggesting that inhibitors of SREBP processing could substantially enhance the potency of current therapies.

Antifungal activity and fungal metabolism of steroidal glycosides of Easter lily (Lilium longiflorum Thunb.) by the plant pathogenic fungus, Botrytis cinerea.

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Munafo, John P; Gianfagna, Thomas J

2011-06-08

Botrytis cinerea Pers. Fr. is a plant pathogenic fungus and the causal organism of blossom blight of Easter lily (Lilium longiflorum Thunb.). Easter lily is a rich source of steroidal glycosides, compounds which may play a role in the plant-pathogen interaction of Easter lily. Five steroidal glycosides, including two steroidal glycoalkaloids and three furostanol saponins, were isolated from L. longiflorum and evaluated for fungal growth inhibition activity against B. cinerea, using an in vitro plate assay. All of the compounds showed fungal growth inhibition activity; however, the natural acetylation of C-6''' of the terminal glucose in the steroidal glycoalkaloid, (22R,25R)-spirosol-5-en-3β-yl O-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl-β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside (2), increased antifungal activity by inhibiting the rate of metabolism of the compound by B. cinerea. Acetylation of the glycoalkaloid may be a plant defense response to the evolution of detoxifying mechanisms by the pathogen. The biotransformation of the steroidal glycoalkaloids by B. cinerea led to the isolation and characterization of several fungal metabolites. The fungal metabolites that were generated in the model system were also identified in Easter lily tissues infected with the fungus by LC-MS. In addition, a steroidal glycoalkaloid, (22R,25R)-spirosol-5-en-3β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (6), was identified as both a fungal metabolite of the steroidal glycoalkaloids and as a natural product in L. longiflorum for the first time.

Isolation and in vitro cultivation of the aphid pathogenic fungus Entomophthora planchoniana.

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Freimoser, F M; Jensen, A B; Tuor, U; Aebi, M; Eilenberg, J

2001-12-01

Entomophthora planchoniana is an important fungal pathogen of aphids. Although Entomophthora chromaphidis has been considered a synonym for E. planchoniana, the two species are now separated, and E. planchoniana is reported not to grow in vitro. In this paper, we describe for the first time the isolation and cultivation of this species. Entomophthora planchoniana was isolated from a population of Ovatus crataegarius (Homoptera, Aphididae), which was infected by E. planchoniana only. The isolates did not sporulate, but the sequence of the small subunit rDNA and the restriction fragment length polymorphism patterns of the first part of the large subunit rDNA and the ITS II region confirm that the isolates were E. planchoniana. The isolated fungus grew in a medium consisting of Grace's insect cell culture medium supplemented with lactalbumin hydrolysate, yeastolate, and 10% fetal bovine serum or in GLEN medium with 10% fetal bovine serum. Vegetative cells of E. planchoniana were long and club-shaped and did not stain with Calcofluor, thus suggesting that they were protoplasts.

Antifungal activity against plant pathogens of metabolites from the endophytic fungus Cladosporium cladosporioides.

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Wang, Xiaoning; Radwan, Mohamed M; Taráwneh, Amer H; Gao, Jiangtao; Wedge, David E; Rosa, Luiz H; Cutler, Horace G; Cutler, Stephen J

2013-05-15

Bioassay-guided fractionation of Cladosporium cladosporioides (Fresen.) de Vries extracts led to the isolation of four compounds, including cladosporin, 1; isocladosporin, 2; 5'-hydroxyasperentin, 3; and cladosporin-8-methyl ether, 4. An additional compound, 5',6-diacetylcladosporin, 5, was synthesized by acetylation of compound 3. Compounds 1-5 were evaluated for antifungal activity against plant pathogens. Phomopsis viticola was the most sensitive fungus to the tested compounds. At 30 μM, compound 1 exhibited 92.7, 90.1, 95.4, and 79.9% growth inhibition against Colletotrichum acutatum , Colletotrichum fragariae , Colletotrichum gloeosporioides , and P. viticola, respectively. Compound 2 showed 50.4, 60.2, and 83.0% growth inhibition at 30 μM against Co. fragariae, Co. gloeosporioides, and P. viticola, respectively. Compounds 3 and 4 were isolated for the first time from Cl. cladosporioides. Moreover, the identification of essential structural features of the cladosporin nuclei has also been evaluated. These structures provide new templates for the potential treatment and management of plant diseases.

Diversifying Selection in the Wheat Stem Rust Fungus Acts Predominantly on Pathogen-Associated Gene Families and Reveals Candidate Effectors

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Jana eSperschneider

2014-09-01

Full Text Available Plant pathogens cause severe losses to crop plants and threaten global food production. One striking example is the wheat stem rust fungus, Puccinia graminis f. sp. tritici, which can rapidly evolve new virulent pathotypes in response to resistant host lines. Like several other filamentous fungal and oomycete plant pathogens, its genome features expanded gene families that have been implicated in host-pathogen interactions, possibly encoding effector proteins that interact directly with target host defence proteins. Previous efforts to understand virulence largely relied on the prediction of secreted, small and cysteine-rich proteins as candidate effectors and thus delivered an overwhelming number of candidates. Here, we implement an alternative analysis strategy that uses the signal of adaptive evolution as a line of evidence for effector function, combined with comparative information and expression data. We demonstrate that in planta up-regulated genes that are rapidly evolving are found almost exclusively in pathogen-associated gene families, affirming the impact of host-pathogen co-evolution on genome structure and the adaptive diversification of specialised gene families. In particular, we predict 42 effector candidates that are conserved only across pathogens, induced during infection and rapidly evolving. One of our top candidates has recently been shown to induce genotype-specific hypersensitive cell death in wheat. This shows that comparative genomics incorporating the evolutionary signal of adaptation is powerful for predicting effector candidates for laboratory verification. Our system can be applied to a wide range of pathogens and will give insight into host-pathogen dynamics, ultimately leading to progress in strategies for disease control.

Glucosylceramide Administration as a Vaccination Strategy in Mouse Models of Cryptococcosis.

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Visesato Mor

Full Text Available Cryptococcus neoformans is an opportunistic fungal pathogen and the causative agent of the disease cryptococcosis. Cryptococcosis is initiated as a pulmonary infection and in conditions of immune deficiency disseminates to the blood stream and central nervous system, resulting in life-threatening meningoencephalitis. A number of studies have focused on the development of a vaccine against Cryptococcus, primarily utilizing protein-conjugated components of the Cryptococcus polysaccharide capsule as antigen. However, there is currently no vaccine against Cryptococcus in the clinic. Previous studies have shown that the glycosphingolipid, glucosylceramide (GlcCer, is a virulence factor in C. neoformans and antibodies against this lipid inhibit fungal growth and cell division. In the present study, we have investigated the possibility of using GlcCer as a therapeutic agent against C. neoformans infections in mouse models of cryptococcosis. GlcCer purified from a non-pathogenic fungus, Candida utilis, was administered intraperitoneally, prior to infecting mice with a lethal dose of C. neoformans. GlcCer administration prevented the dissemination of C. neoformans from the lungs to the brain and led to 60% mouse survival. GlcCer administration did not cause hepatic injury and elicited an anti-GlcCer antibody response, which was observed independent of the route of administration and the strains of mouse. Taken together, our results suggest that fungal GlcCer can protect mice against lethal doses of C. neoformans infection and can provide a viable vaccination strategy against Cryptococcus.

Glucosylceramide Administration as a Vaccination Strategy in Mouse Models of Cryptococcosis.

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Mor, Visesato; Farnoud, Amir M; Singh, Ashutosh; Rella, Antonella; Tanno, Hiromasa; Ishii, Keiko; Kawakami, Kazuyoshi; Sato, Toshiya; Del Poeta, Maurizio

2016-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen and the causative agent of the disease cryptococcosis. Cryptococcosis is initiated as a pulmonary infection and in conditions of immune deficiency disseminates to the blood stream and central nervous system, resulting in life-threatening meningoencephalitis. A number of studies have focused on the development of a vaccine against Cryptococcus, primarily utilizing protein-conjugated components of the Cryptococcus polysaccharide capsule as antigen. However, there is currently no vaccine against Cryptococcus in the clinic. Previous studies have shown that the glycosphingolipid, glucosylceramide (GlcCer), is a virulence factor in C. neoformans and antibodies against this lipid inhibit fungal growth and cell division. In the present study, we have investigated the possibility of using GlcCer as a therapeutic agent against C. neoformans infections in mouse models of cryptococcosis. GlcCer purified from a non-pathogenic fungus, Candida utilis, was administered intraperitoneally, prior to infecting mice with a lethal dose of C. neoformans. GlcCer administration prevented the dissemination of C. neoformans from the lungs to the brain and led to 60% mouse survival. GlcCer administration did not cause hepatic injury and elicited an anti-GlcCer antibody response, which was observed independent of the route of administration and the strains of mouse. Taken together, our results suggest that fungal GlcCer can protect mice against lethal doses of C. neoformans infection and can provide a viable vaccination strategy against Cryptococcus.

Cryptococcus neoformans granuloma in the lung and spinal cord of a free-ranging cheetah (Acinonyx jubatus). A clinical report and literature review.

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Millward, I R; Williams, M C

2005-12-01

A 6-year-old, male, wild-born, free-ranging cheetah (Acinonyx jubatus) was evaluated for acute onset of progressive lameness in the right hind limb. Survey radiographs were unrewarding and myelography indicated an intramedullary compressive mass at the L3-L4 region. A fine needle aspirate of the lesion indicated the presence of Cryptococcus organisms. Necropsy confirmed the presence of granulomas (cryptococcoma) in the lung and the spinal cord (meningomyelitis) caused by Cryptococcus neoformans var. gattii. Cryptococcus neoformans is a yeast-like organism that is a potential pathogen to many species. Initial infection is thought to be of respiratory origin and then it commonly disseminates systemically from the nasal cavity or lungs to the skin, eyes and central nervous system in particular. The cheetah tested negative for both feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), as have all the previously reported cheetah cases. C. neoformans is a non-contagious, opportunistic organism and is the most common systemic mycoses in domestic cats and the cheetah.

White-Nose Syndrome Fungus in a 1918 Bat Specimen from France

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Campana, Michael G.; Kurata, Naoko P.; Foster, Jeffrey T.; Helgen, Lauren E.; Reeder, DeeAnn M.; Fleischer, Robert C.; Helgen, Kristofer M.

2017-01-01

White-nose syndrome, first diagnosed in North America in 2006, causes mass deaths among bats in North America. We found the causative fungus, Pseudogymnoascus destructans, in a 1918 sample collected in Europe, where bats have now adapted to the fungus. These results are consistent with a Eurasian origin of the pathogen.

White-Nose Syndrome Fungus in a 1918 Bat Specimen from France.

Science.gov (United States)

Campana, Michael G; Kurata, Naoko P; Foster, Jeffrey T; Helgen, Lauren E; Reeder, DeeAnn M; Fleischer, Robert C; Helgen, Kristofer M

2017-09-01

White-nose syndrome, first diagnosed in North America in 2006, causes mass deaths among bats in North America. We found the causative fungus, Pseudogymnoascus destructans, in a 1918 sample collected in Europe, where bats have now adapted to the fungus. These results are consistent with a Eurasian origin of the pathogen.

Cryptococcus neoformans hyperfilamentous strain is hypervirulent in a murine model of cryptococcal meningoencephalitis.

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Marianna Feretzaki

Full Text Available Cryptococcus neoformans is a human fungal pathogen that causes lethal infections of the lung and central nervous system in immunocompromised individuals. C. neoformans has a defined bipolar sexual life cycle with a and α mating types. During the sexual cycle, which can occur between cells of opposite mating types (bisexual reproduction or cells of one mating type (unisexual reproduction, a dimorphic transition from yeast to hyphal growth occurs. Hyphal development and meiosis generate abundant spores that, following inhalation, penetrate deep into the lung to enter the alveoli, germinate, and establish a pulmonary infection growing as budding yeast cells. Unisexual reproduction has been directly observed only in the Cryptococcus var. neoformans (serotype D lineage under laboratory conditions. However, hyphal development has been previously associated with reduced virulence and the serotype D lineage exhibits limited pathogenicity in the murine model. In this study we show that the serotype D hyperfilamentous strain XL280α is hypervirulent in an animal model. It can grow inside the lung of the host, establish a pulmonary infection, and then disseminate to the brain to cause cryptococcal meningoencephalitis. Surprisingly, this hyperfilamentous strain triggers an immune response polarized towards Th2-type immunity, which is usually observed in the highly virulent sibling species C. gattii, responsible for the Pacific Northwest outbreak. These studies provide a technological advance that will facilitate analysis of virulence genes and attributes in C. neoformans var. neoformans, and reveal the virulence potential of serotype D as broader and more dynamic than previously appreciated.

The link between morphotype transition and virulence in Cryptococcus neoformans.

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Linqi Wang

Full Text Available Cryptococcus neoformans is a ubiquitous human fungal pathogen. This pathogen can undergo morphotype transition between the yeast and the filamentous form and such morphological transition has been implicated in virulence for decades. Morphotype transition is typically observed during mating, which is governed by pheromone signaling. Paradoxically, components specific to the pheromone signaling pathways play no or minimal direct roles in virulence. Thus, the link between morphotype transition and virulence and the underlying molecular mechanism remain elusive. Here, we demonstrate that filamentation can occur independent of pheromone signaling and mating, and both mating-dependent and mating-independent morphotype transition require the transcription factor Znf2. High expression of Znf2 is necessary and sufficient to initiate and maintain sex-independent filamentous growth under host-relevant conditions in vitro and during infection. Importantly, ZNF2 overexpression abolishes fungal virulence in murine models of cryptococcosis. Thus, Znf2 bridges the sex-independent morphotype transition and fungal pathogenicity. The impacts of Znf2 on morphological switch and pathogenicity are at least partly mediated through its effects on cell adhesion property. Cfl1, a Znf2 downstream factor, regulates morphogenesis, cell adhesion, biofilm formation, and virulence. Cfl1 is the first adhesin discovered in the phylum Basidiomycota of the Kingdom Fungi. Together with previous findings in other eukaryotic pathogens, our findings support a convergent evolution of plasticity in morphology and its impact on cell adhesion as a critical adaptive trait for pathogenesis.

The origin of Ceratocystis fagacearum, the oak wilt fungus

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Jennifer Juzwik; Thomas C. Harrington; William L. MacDonald; David N. Appel

2008-01-01

The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown. The pathogen may have been endemic at a low incidence until increased disturbances, changes...

Two Distinct Approaches for CRISPR-Cas9-Mediated Gene Editing in Cryptococcus neoformans and Related Species.

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Wang, Ping

2018-06-27

Cryptococcus neoformans and related species are encapsulated basidiomycetous fungi that cause meningoencephalitis in individuals with immune deficiency. This pathogen has a tractable genetic system; however, gene disruption via electroporation remains difficult, while biolistic transformation is often limited by lack of multiple genetic markers and the high initial cost of equipment. The approach using clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) has become the technology of choice for gene editing in many organisms due to its simplicity, efficiency, and versatility. The technique has been successfully demonstrated in C. neoformans and Cryptococcus deneoformans in which two DNA plasmids expressing either the Streptococcus pyogenes CAS9 gene or the guide RNA (gRNA) were employed. However, potential adverse effects due to constitutive expression and the time-consuming process of constructing vectors to express each gRNA remain as a primary barrier for wide adaptation. This report describes the delivery of preassembled CRISPR-Cas9-gRNA ribonucleoproteins (RNPs) via electroporation that is able to generate edited mutant alleles. RNP-mediated CRISPR-Cas9 was used to replace the wild-type GIB2 gene encoding a Gβ-like/RACK1 Gib2 protein with a gib2 :: NAT allele via homologous recombination in both C. neoformans and C. deneoformans In addition, a DNA plasmid (pCnCas9:U6-gRNA) that expresses both Cas9 and gRNA, allowing for convenient yet low-cost DNA-mediated gene editing, is described. pCnCas9:U6-gRNA contains an endogenous U6 promoter for gRNA expression and restriction sites for one-step insertion of a gRNA. These approaches and resources provide new opportunities to accelerate genetic studies of Cryptococcus species. IMPORTANCE For genetic studies of the Cryptococcus genus, generation of mutant strains is often hampered by a limited number of selectable genetic markers, the tedious process of vector

The Crucial Role of Biofilms in Cryptococcus neoformans Survival within Macrophages and Colonization of the Central Nervous System

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Lilit Aslanyan

2017-02-01

Full Text Available Cryptococcus neoformans is an encapsulated yeast-like fungus capable of causing life threatening meningoencephalitis in patients with impaired immunity. This microbe primarily infects the host via inhalation but has the ability to disseminate to the central nervous system (CNS either as a single cell or inside of macrophages. Upon traversing the blood brain barrier, C. neoformans has the capacity to form biofilm-like structures known as cryptococcomas. Hence, we will discuss the C. neoformans elements contributing to biofilm formation including the fungus’ ability to survive in the acidic environment of a macrophage phagosome and inside of the CNS. The purpose of this mini-review is to instill fresh interest in understanding the importance of biofilms on fungal pathogenesis.

Environmental sampling of Ceratonia siliqua (carob) trees in Spain reveals the presence of the rare Cryptococcus gattii genotype AFLP7/VGIV.

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Linares, Carlos; Colom, María Francisca; Torreblanca, Marina; Esteban, Violeta; Romera, Álvaro; Hagen, Ferry

2015-01-01

Cryptococcus gattii is a pathogenic basidiomycetous yeast that is emerging in temperate climate zones worldwide. C. gattii has repetitively been isolated from numerous tree species. Ongoing environmental sampling and molecular characterization is essential to understand the presence of this primary pathogenic microorganism in the Mediterranean environment. To report the first isolation of the rare C. gattii genotype AFLP7/VGIV from the environment in Europe. Samples were collected from woody debris of carob trees (Ceratonia siliqua) and olive trees (Olea europaea) in El Perelló, Tarragona, Spain. Cryptococcus species were further characterized by using URA5-RFLP, MALDI-TOF, AFLP and MLST. The antifungal susceptibility profile to amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, posaconazole and voriconazole was determined using Sensititre Yeast One and E-test. Cultures from one carob tree revealed the presence of ten Cryptococcus-like colonies. One colony was identified as C. gattii, and subsequent molecular characterization showed that it was an α mating-type that belonged to the rare genotype AFLP7/VGIV. Antifungal susceptibility testing showed values within the range of sensitivity described for other isolates of the same genotype and within the epidemiological cutoff values for this species. The isolation of the rare C. gattii genotype AFLP7/VGIV in Spain is the first report in the European environment, implying the possible presence in other regions of the Mediterranean area, and underlines that clinicians must be aware for C. gattii infections in healthy individuals. Copyright © 2014 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Epidemiologische trends in cryptokokkose : De Cryptococcus gattii-uitbraak in Canada

NARCIS (Netherlands)

Hagen, F; Boekhout, T

2006-01-01

Cryptococcosis is, when untreated, a fatal disease, which in the Netherlands is mainly caused by the basidiomycetous yeast Cryptococcus neoformans, and in more rare cases by Cryptococcus gattii. Infections with C. gattii occur almost only in immunocompetent individuals, while C. neoformans has a

Hydrophobins contribute to root colonization and stress responses in the rhizosphere-competent insect pathogenic fungus Beauveria bassiana.

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Moonjely, Soumya; Keyhani, Nemat O; Bidochka, Michael J

2018-04-01

The hyd1/hyd2 hydrophobins are important constituents of the conidial cell wall of the insect pathogenic fungus Beauveria bassiana. This fungus can also form intimate associations with several plant species. Here, we show that inactivation of two Class I hydrophobin genes, hyd1 or hyd2, significantly decreases the interaction of B. bassiana with bean roots. Curiously, the ∆hyd1/∆hyd2 double mutant was less impaired in root association than Δhyd1 or Δhyd2. Loss of hyd genes affected growth rate, conidiation ability and oosporein production. Expression patterns for genes involved in conidiation, cell wall integrity, insect virulence, signal transduction, adhesion, hydrophobicity and oosporein production were screened in the deletion mutants grown in different conditions. Repression of the major MAP-Kinase signal transduction pathways (Slt2 MAPK pathway) was observed that was more pronounced in the single versus double hyd mutants under certain conditions. The ∆hyd1/∆hyd2 double mutant showed up-regulation of the Hog1 MAPK and the Msn2 transcription factor under certain conditions when compared to the wild-type or single hyd mutants. The expression of the bad2 adhesin and the oosporein polyketide synthase 9 gene was severely reduced in all of the mutants. On the other hand, fewer changes were observed in the expression of key conidiation and cell wall integrity genes in hyd mutants compared to wild-type. Taken together, the data from this study indicated pleiotropic consequences of deletion of hyd1 and hyd2 on signalling and stress pathways as well as the ability of the fungus to form stable associations with plant roots.

The first reported case of canine subcutaneous Cryptococcus flavescens infection.

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Kano, Rui; Ishida, Rinei; Nakane, Shinsuke; Sekiguchi, Maiko; Hasegawa, Atsuhiko; Kamata, Hiroshi

2012-03-01

This report describes the first documented case of subcutaneous infection due to Cryptococcus flavescens in a dog. The chief symptoms of the patient dog were abscessed lesions on the dorsal muzzle, right eyelid, and lower jaw. Biopsy specimens from the lesions on the dorsal muzzle and lower jaw showed pyogranulomatous inflammation with numerous yeast cells. The patient dog was diagnosed with a subcutaneous fungal infection and orally received 5 mg/kg itraconazole once a day for 2 months, the abscesses disappeared. After 1 month at the end of treatment, the skin lesions did not redevelop. Isolates from the biopsy specimens were identified as C. flavescens by molecular analysis as well as morphologic and biochemical examination, indicating that C. flavescens is a potential canine pathogen.

Molecular and cellular responses of the pathogenic fungus Lomentospora prolificans to the antifungal drug voriconazole.

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Pellon, Aize; Ramirez-Garcia, Andoni; Buldain, Idoia; Antoran, Aitziber; Rementeria, Aitor; Hernando, Fernando L

2017-01-01

The filamentous fungus Lomentospora (Scedosporium) prolificans is an emerging opportunistic pathogen associated with fatal infections in patients with disturbed immune function. Unfortunately, conventional therapies are hardly of any use against this fungus due to its intrinsic resistance. Therefore, we performed an integrated study of the L. prolificans responses to the first option to treat these mycoses, namely voriconazole, with the aim of unveiling mechanisms involved in the resistance to this compound. To do that, we used a wide range of techniques, including fluorescence and electron microscopy to study morphological alterations, ion chromatography to measure changes in cell-wall carbohydrate composition, and proteomics-based techniques to identify the proteins differentially expressed under the presence of the drug. Significantly, we showed drastic changes occurring in cell shape after voriconazole exposure, L. prolificans hyphae being shorter and wider than under control conditions. Interestingly, we proved that the architecture and carbohydrate composition of the cell wall had been modified in the presence of the drug. Specifically, L. prolificans constructed a more complex organelle with a higher presence of glucans and mannans. In addition to this, we identified several differentially expressed proteins, including Srp1 and heat shock protein 70 (Hsp70), as the most overexpressed under voriconazole-induced stress conditions. The mechanisms described in this study, which may be directly related to L. prolificans antifungal resistance or tolerance, could be used as targets to improve existing therapies or to develop new ones in order to successfully eliminate these mycoses.

Development of a greenhouse-based inoculation protocol for the fungus Colletotrichum cereale pathogenic to annual bluegrass (Poa annua

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Lisa A. Beirn

2015-08-01

Full Text Available The fungus Colletotrichum cereale incites anthracnose disease on Poa annua (annual bluegrass turfgrass. Anthracnose disease is geographically widespread throughout the world and highly destructive to cool-season turfgrasses, with infections by C. cereale resulting in extensive turf loss. Comprehensive research aimed at controlling turfgrass anthracnose has been performed in the field, but knowledge of the causal organism and its basic biology is still needed. In particular, the lack of a reliable greenhouse-based inoculation protocol performed under controlled environmental conditions is an obstacle to the study of C. cereale and anthracnose disease. Our objective was to develop a consistent and reproducible inoculation protocol for the two major genetic lineages of C. cereale. By adapting previously successful field-based protocols and combining with components of existing inoculation procedures, the method we developed consistently produced C. cereale infection on two susceptible P. annua biotypes. Approximately 7 to 10 days post-inoculation, plants exhibited chlorosis and thinning consistent with anthracnose disease symptomology. Morphological inspection of inoculated plants revealed visual signs of the fungus (appressoria and acervuli, although acervuli were not always present. After stringent surface sterilization of inoculated host tissue, C. cereale was consistently re-isolated from symptomatic tissue. Real-time PCR detection analysis based on the Apn2 marker confirmed the presence of the pathogen in host tissue, with both lineages of C. cereale detected from all inoculated plants. When a humidifier was not used, no infection developed for any biotypes or fungal isolates tested. The inoculation protocol described here marks significant progress for in planta studies of C. cereale, and will enable scientifically reproducible investigations of the biology, infectivity and lifestyle of this important grass pathogen.

Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival

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Ayat Al-Laaeiby

2016-03-01

Full Text Available The dematiaceous (melanised fungus Lomentospora (Scedosporium prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H2O2, UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN-melanin biosynthetic enzymes polyketide synthase (PKS1, tetrahydroxynapthalene reductase (4HNR and scytalone dehydratase (SCD1. Infectious propagules (spores of the wild-type strain 3.1 were black/brown, whereas spores of the PKS-deficient mutant ΔLppks1::hph were white. Complementation of the albino mutant ΔLppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant ΔLp4hnr::hph and SCD-deficient mutant ΔLpscd1::hph both produced orange-yellow spores. The mutants ΔLppks1::hph and ΔLp4hnr::hph showed significant reductions in spore survival following H2O2 treatment, while spores of ΔLpscd1::hph and the ΔLppks1::hph complemented strain ΔLppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants ΔLp4hnr::hph and ΔLpscd1::hph and complemented strain ΔLppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of ΔLppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants ΔLp4hnr::hph and ΔLppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not

Cryptococcus gattii : A dilemma in diagnosis and treatment in sub ...

African Journals Online (AJOL)

Sub-Saharan Africa contributes at least 70% of the global cryptococcal meningoencephalitis cases each year and the majority of cases are caused by the Cryptococcus neoformans species. We present a case of meningoencephalitis due to Cryptococcus gattii in an 18 year old apparently immunocompetent male patient ...

Identification and validation of reference genes for qRT-PCR studies of the obligate aphid pathogenic fungus Pandora neoaphidis during different developmental stages

OpenAIRE

Zhang, Shutao; Chen, Chun; Xie, Tingna; Ye, Sudan

2017-01-01

The selection of stable reference genes is a critical step for the accurate quantification of gene expression. To identify and validate the reference genes in Pandora neoaphidis-an obligate aphid pathogenic fungus-the expression of 13classical candidate reference genes were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction(qPCR) at four developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae). Four statistical algorithms, inc...

The ability to cause infection in a pathogenic fungus uncovers a new biological feature of honey bee viruses.

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Li, Zhiguo; Su, Songkun; Hamilton, Michele; Yan, Limin; Chen, Yanping

2014-07-01

We demonstrated that honey bee viruses including Deformed wing virus (DWV), Black queen cell virus (BQCV) and Israeli acute paralysis virus (IAPV) could infect and replicate in the fungal pathogen Ascosphaera apis that causes honey bee chalkbrood disease, revealing a novel biological feature of honey bee viruses. The phylogenetic analysis show that viruses of fungal and honey bee origins form two clusters in the phylogenetic trees distinctly and that host range of honey bee viruses is dynamic. Further studies are warranted to investigate the impact of the viruses on the fitness of their fungal host and phenotypic effects the virus-fungus combination has on honey bee hosts. Published by Elsevier Inc.

Expressed sequences tags of the anther smut fungus, Microbotryum violaceum, identify mating and pathogenicity genes

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Devier Benjamin

2007-08-01

Full Text Available Abstract Background The basidiomycete fungus Microbotryum violaceum is responsible for the anther-smut disease in many plants of the Caryophyllaceae family and is a model in genetics and evolutionary biology. Infection is initiated by dikaryotic hyphae produced after the conjugation of two haploid sporidia of opposite mating type. This study describes M. violaceum ESTs corresponding to nuclear genes expressed during conjugation and early hyphal production. Results A normalized cDNA library generated 24,128 sequences, which were assembled into 7,765 unique genes; 25.2% of them displayed significant similarity to annotated proteins from other organisms, 74.3% a weak similarity to the same set of known proteins, and 0.5% were orphans. We identified putative pheromone receptors and genes that in other fungi are involved in the mating process. We also identified many sequences similar to genes known to be involved in pathogenicity in other fungi. The M. violaceum EST database, MICROBASE, is available on the Web and provides access to the sequences, assembled contigs, annotations and programs to compare similarities against MICROBASE. Conclusion This study provides a basis for cloning the mating type locus, for further investigation of pathogenicity genes in the anther smut fungi, and for comparative genomics.

An in vivo transcriptome for entomopathogenic fungus Metarhizium robertsii ARSEF 2575

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Molecular mechanisms underlying the pathogenic process of the insect pathogen Metarhizium robertsii ARSEF 2575 in its host are only partially understood. To probe the transcriptional responses of the fungus during the interaction with insects, we have developed a method to specifically recover patho...

Cryptococcus: isolamento ambiental e caracterização bioquímica

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E.C. Araújo Júnior

2015-08-01

Full Text Available O gênero Cryptococcus caracteriza-se por ser uma levedura responsável por infecção sistêmica, causada pelas espécies Cryptococcus neoformans e Cryptococcus gattii. O fungo é encontrado em substratos de origem animal e vegetal, e a infecção ocorre com a inalação de basidiósporos ou leveduras desidratadas infectantes presentes no ambiente. O presente trabalho teve por objetivo pesquisar a existência de microfocos de Cryptococcussp.em amostras ambientais da cidade de Araçatuba, São Paulo, com a finalidade de minimizar os riscos de contaminação do homem e dos animais, buscando o conhecimento da ecoepidemiologia do Cryptococcus. Foram colhidas 50 amostras oriundas de ocos e troncos de árvores (Cassiasp., Ficussp., Caesalpinea peltophorides de 10 locais representativos do perímetro urbano, as quais foram encaminhadas ao Laboratório de Bacteriologia e Micologia da Faculdade de Medicina Veterinária de Araçatuba-Unesp, onde foram processadas e semeadas em placas de Petri contendo ágar semente de Níger e Sabouraud dextrose com clorafenicol e incubadas à temperatura de 30ºC, por um período não inferior a cinco dias. Posteriormente, foram submetidas às provas bioquímicas: produção de urease, termotolerância a 37ºC e quimiotipagem em ágar CGB (L-canavanina-glicina-azul de bromotimol. A análise dos resultados revelaram que 17 (34% dos cultivos foram positivos para o gênero Cryptococcus, sendo nove (18% para Cryptococcus gattiie oito (16% para Cryptococcus neoformans. Outras leveduras correlacionadas, como Rhodotorula sp. e Candida sp., também foram isoladas. Conclui-se que os basidiósporos de Cryptococcusencontram-se dispersos na natureza, constituindo microfocos ambientais, não vinculados necessariamente a um único hospedeiro.

Cryptococcus neoformans granuloma in the lung and spinal cord of a free-ranging cheetah (Acinonyx jubatus. A clinical report and literature review : clinical communication

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I.R. Millward

2005-06-01

Full Text Available A 6-year-old, male, wild-born, free-ranging cheetah (Acinonyx jubatus was evaluated for acute onset of progressive lameness in the right hind limb. Survey radiographs were unrewarding and myelography indicated an intramedullary compressive mass at the L3-L4 region. A fine needle aspirate of the lesion indicated the presence of Cryptococcus organisms. Necropsy confirmed the presence of granulomas (cryptococcoma in the lung and the spinal cord (meningomyelitis caused by Cryptococcus neoformans var. gattii. Cryptococcus neoformans is a yeast-like organism that is a potential pathogen to many species. Initial infection is thought to be of respiratory origin and then it commonly disseminates systemically from the nasal cavity or lungs to the skin, eyes and central nervous system in particular. The cheetah tested negative for both feline leukaemia virus (FeLV and feline immunodeficiency virus (FIV, as have all the previously reported cheetah cases. C. neoformans is a non-contagious, opportunistic organism and is the most common systemic mycoses in domestic cats and the cheetah.

Cryptococcus neoformans infective endocarditis of native valves in an immunocompetent host

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Moni Roy

Full Text Available With the emergence of Human immunodeficiency virus (HIV and the resulting immunocompromised state, Cryptococcus neoformans infections have gained more importance in clinical practice. Cryptococcal infections in immunocompetent hosts continue to be uncommon. We present a rare case of Cryptococcus neoformans infective endocarditis (IE in a young immunocompetent male. As per our literature review, this is the first reported case of native valve Cryptococcus neoformans endocarditis in an immunocompetent host. All cases till date have been reported in patients with underlying immunocompromised state or prosthetic valve.

The Wor1-like protein Fgp1 regulates pathogenicity, toxin synthesis and reproduction in the phytopathogenic fungus Fusarium graminearum.

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Wilfried Jonkers

Full Text Available WOR1 is a gene for a conserved fungal regulatory protein controlling the dimorphic switch and pathogenicity determents in Candida albicans and its ortholog in the plant pathogen Fusarium oxysporum, called SGE1, is required for pathogenicity and expression of key plant effector proteins. F. graminearum, an important pathogen of cereals, is not known to employ switching and no effector proteins from F. graminearum have been found to date that are required for infection. In this study, the potential role of the WOR1-like gene in pathogenesis was tested in this toxigenic fungus. Deletion of the WOR1 ortholog (called FGP1 in F. graminearum results in greatly reduced pathogenicity and loss of trichothecene toxin accumulation in infected wheat plants and in vitro. The loss of toxin accumulation alone may be sufficient to explain the loss of pathogenicity to wheat. Under toxin-inducing conditions, expression of genes for trichothecene biosynthesis and many other genes are not detected or detected at lower levels in Δfgp1 strains. FGP1 is also involved in the developmental processes of conidium formation and sexual reproduction and modulates a morphological change that accompanies mycotoxin production in vitro. The Wor1-like proteins in Fusarium species have highly conserved N-terminal regions and remarkably divergent C-termini. Interchanging the N- and C- terminal portions of proteins from F. oxysporum and F. graminearum resulted in partial to complete loss of function. Wor1-like proteins are conserved but have evolved to regulate pathogenicity in a range of fungi, likely by adaptations to the C-terminal portion of the protein.

The Role of Amino Acid Permeases and Tryptophan Biosynthesis in Cryptococcus neoformans Survival.

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João Daniel Santos Fernandes

Full Text Available Metabolic diversity is an important factor during microbial adaptation to different environments. Among metabolic processes, amino acid biosynthesis has been demonstrated to be relevant for survival for many microbial pathogens, whereas the association between pathogenesis and amino acid uptake and recycling are less well-established. Cryptococcus neoformans is an opportunistic fungal pathogen with many habitats. As a result, it faces frequent metabolic shifts and challenges during its life cycle. Here we studied the C. neoformans tryptophan biosynthetic pathway and found that the pathway is essential. RNAi indicated that interruptions in the biosynthetic pathway render strains inviable. However, auxotroph complementation can be partially achieved by tryptophan uptake when a non preferred nitrogen source and lower growth temperature are applied, suggesting that amino acid permeases may be the target of nitrogen catabolism repression (NCR. We used bioinformatics to search for amino acid permeases in the C. neoformans and found eight potential global permeases (AAP1 to AAP8. The transcriptional profile of them revealed that they are subjected to regulatory mechanisms which are known to respond to nutritional status in other fungi, such as (i quality of nitrogen (Nitrogen Catabolism Repression, NCR and carbon sources (Carbon Catabolism Repression, CCR, (ii amino acid availability in the extracellular environment (SPS-sensing and (iii nutritional deprivation (Global Amino Acid Control, GAAC. This study shows that C. neoformans has fewer amino acid permeases than other model yeasts, and that these proteins may be subjected to complex regulatory mechanisms. Our data suggest that the C. neoformans tryptophan biosynthetic pathway is an excellent pharmacological target. Furthermore, inhibitors of this pathway cause Cryptococcus growth arrest in vitro.

Efficacy of Entomopathogenic Fungus Beauveria Bassiana and Gamma Irradiation Against the Greater Date Moth, Arenipses Sabella

International Nuclear Information System (INIS)

Mikhaiel, A.A.; Abul Fadl, H.A.A.

2011-01-01

The fungus Beauveria bassiana (Bals.) was isolated locally from dead larvae of the greater date moth, Arenipses sabella (Hampson) (Lepidoptera: Pyralidae). The effect of three exposure methods and two environmental factors (temperature and relative humidity) on pathogenicity of the fungus with different concentrations to A. sabella second instar larvae were examined. The study demonstrated that the entomopathogenic fungus was most efficient in the control of second instar larvae at 25 degree C and 100% humidity and the percent of mortality was increased when increasing the concentration of fungus. The mode of exposure of fungus to larvae directly sprayed, larvae exposed to the treated dates or larvae both sprayed and exposed to the treated dates showed 56.66, 26.66 and 75% mortality, respectively, at concentration 1x10 10 spores/ml and three days post-treatment. The F1 larvae resulting from irradiated male pupae with 150 Gy were more susceptible to pathogenic fungus at low concentration ((1x10 8 spores/ml) than non-irradiated ones. The scanning electron microscope was used to delineate the morphological stages of fungus to the germinated conidia and the hyphae penetrating the larva cuticle.

Molecular and cellular responses of the pathogenic fungus Lomentospora prolificans to the antifungal drug voriconazole.

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Aize Pellon

Full Text Available The filamentous fungus Lomentospora (Scedosporium prolificans is an emerging opportunistic pathogen associated with fatal infections in patients with disturbed immune function. Unfortunately, conventional therapies are hardly of any use against this fungus due to its intrinsic resistance. Therefore, we performed an integrated study of the L. prolificans responses to the first option to treat these mycoses, namely voriconazole, with the aim of unveiling mechanisms involved in the resistance to this compound. To do that, we used a wide range of techniques, including fluorescence and electron microscopy to study morphological alterations, ion chromatography to measure changes in cell-wall carbohydrate composition, and proteomics-based techniques to identify the proteins differentially expressed under the presence of the drug. Significantly, we showed drastic changes occurring in cell shape after voriconazole exposure, L. prolificans hyphae being shorter and wider than under control conditions. Interestingly, we proved that the architecture and carbohydrate composition of the cell wall had been modified in the presence of the drug. Specifically, L. prolificans constructed a more complex organelle with a higher presence of glucans and mannans. In addition to this, we identified several differentially expressed proteins, including Srp1 and heat shock protein 70 (Hsp70, as the most overexpressed under voriconazole-induced stress conditions. The mechanisms described in this study, which may be directly related to L. prolificans antifungal resistance or tolerance, could be used as targets to improve existing therapies or to develop new ones in order to successfully eliminate these mycoses.

Antagonistic Activity of Probiotic Organism Against Vibrio cholerae and Cryptococcus neoformans

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Vidya, R.

2010-01-01

Full Text Available The microbes are useful in many ways in the modern world. Probiotics one of them, which refers to, acid adherence bacteria in the intestinal cells, are able to survive at low pH and produce large amount of lactic acid. The present investigation deals with the antagonistic activity of Lactobacillus acidophilus organism against pathogens. The organism was isolated from the curd sample. Identification of bacteria was done by various biochemical testing. The present study revealed that L. acidophilus inhibits Vibrio cholerae more efficiently than Streptococcus pneumoniae and Shigella dysentriae. When L. acidophilus and V. cholerae were grown together, L. acidophilus dominated the growth and competitively inhibited the growth of V. cholerae. L. acidophilus was also found to inhibit Cryptococcus neoformans.

Neurocriptococose por Cryptococcus neoformans não capsulado

OpenAIRE

Lacaz, C.S.; Heins-Vaccari, Elisabeth M.; Melo, Natalina T.; Moreno-Carvalho, O.A.; Sampaio, M.L.S.; Nogueira, L.S.; Badaró, R.J.S.; Livramento, J.A.

1993-01-01

Os autores registram um caso de neurocriptococose em paciente HIV-negativo, por Cryptococcus neoformans acapsulado ou deficiente em cápsula. O quadro neurológico era de meningoencefalite subaguda, compatível ao diagnóstico de neurotuberculose, pelo exame do líquido cefalorraqueano (LCR), Estruturas leveduriformes foram encontradas no interior de macrófagos, ao exame citomorfológico do LCR. Cultivo do sedimento do LCR revelou a presença de Cryptococcus neoformans não capsulado (identificação b...

Proteome Analysis of the Plant Pathogenic Fungus Monilinia laxa Showing Host Specificity

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Olja Bregar

2012-01-01

Full Text Available Brown rot fungus Monilinia laxa (Aderh. & Ruhl. Honey is an important plant pathogen in stone and pome fruits in Europe. We applied a proteomic approach in a study of M. laxa isolates obtained from apples and apricots in order to show the host specifity of the isolates and to analyse differentially expressed proteins in terms of host specifity, fungal pathogenicity and identification of candidate proteins for diagnostic marker development. Extracted mycelium proteins were separated by 2-D electrophoresis (2-DE and visualized by Coomassie staining in a non-linear pH range of 3–11 and Mr of 14–116 kDa. We set up a 2-DE reference map of M. laxa, resolving up to 800 protein spots, and used it for image analysis. The average technical coefficient of variance (13 % demonstrated a high reproducibility of protein extraction and 2-D polyacrylamide gel electrophoresis (2-DE PAGE, and the average biological coefficient of variance (23 % enabled differential proteomic analysis of the isolates. Multivariate statistical analysis (principal component analysis discriminated isolates from two different hosts, providing new data that support the existence of a M. laxa specialized form f. sp. mali, which infects only apples. A total of 50 differentially expressed proteins were further analyzed by LC-MS/MS, yielding 41 positive identifications. The identified mycelial proteins were functionally classified into 6 groups: amino acid and protein metabolism, energy production, carbohydrate metabolism, stress response, fatty acid metabolism and other proteins. Some proteins expressed only in apple isolates have been described as virulence factors in other fungi. The acetolactate synthase was almost 11-fold more abundant in apple-specific isolates than in apricot isolates and it might be implicated in M. laxa host specificity. Ten proteins identified only in apple isolates are potential candidates for the development of M. laxa host-specific diagnostic markers.

Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest.

Science.gov (United States)

Hagen, Ferry; Ceresini, Paulo C; Polacheck, Itzhack; Ma, Hansong; van Nieuwerburgh, Filip; Gabaldón, Toni; Kagan, Sarah; Pursall, E Rhiannon; Hoogveld, Hans L; van Iersel, Leo J J; Klau, Gunnar W; Kelk, Steven M; Stougie, Leen; Bartlett, Karen H; Voelz, Kerstin; Pryszcz, Leszek P; Castañeda, Elizabeth; Lazera, Marcia; Meyer, Wieland; Deforce, Dieter; Meis, Jacques F; May, Robin C; Klaassen, Corné H W; Boekhout, Teun

2013-01-01

Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause of several additional case clusters at localities outside of the tropical and subtropical climate zones where the species normally occurs. In every case, the causative agent belongs to a previously rare genotype of C. gattii called AFLP6/VGII, but the origin of the outbreak clades remains enigmatic. Here we used phylogenetic and recombination analyses, based on AFLP and multiple MLST datasets, and coalescence gene genealogy to demonstrate that these outbreaks have arisen from a highly-recombining C. gattii population in the native rainforest of Northern Brazil. Thus the modern virulent C. gattii AFLP6/VGII outbreak lineages derived from mating events in South America and then dispersed to temperate regions where they cause serious infections in humans and animals.

Transmembrane transporter expression regulated by the glucosylceramide pathway in Cryptococcus neoformans.

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Singh, Arpita; Rella, Antonella; Schwacke, John; Vacchi-Suzzi, Caterina; Luberto, Chiara; Del Poeta, Maurizio

2015-11-16

disrupt transmembrane signaling complex, which in turn contributes to cryptococcal osmotic, pH, ion homeostasis and its pathobiology. Six genes identified from gene expression microarrays by gene set enrichment analysis and validated by RT-PCR, are membrane located and associated with the growth defect at neutral-alkaline pH due to the absence and or presence of a structurally modified GlcCer. They may be involved in the transmembrane signaling network in Cryptococcus neoformans, and therefore the pathobiology of the fungus in these conditions.

Curvularia trifolii a new for Poland pathogen of gladiolus

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Czesław Zamorski

2013-12-01

Full Text Available A new for Poland gladiolus disease is described. Microscopic data as well as pathogenicity tests proved that the fungus Curvularia trifolii f.sp. gladioli is the caused of this disease. Among 17 gladiolus cultivars the most susceptible were: 'Aldebaran', 'Benares' and 'Lovely Melody' while the cultivars 'Oscar' and 'Decisio' showed the lowest susceptibility to the pathogen, In laboratory tests fungicides containing fenarimol PMC, vinclozolin and captafol were highly toxic for the fungus Curvularia trifolii f. sp. gladioli. Other fungicides such as thiuram and captan showed only a slight effectiveness, while chlorothalonil and carbendazim were not at all toxic for the studied fungus.

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

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Camacho, Emma; Chrissian, Christine; Cordero, Radames J B; Liporagi-Lopes, Livia; Stark, Ruth E; Casadevall, Arturo

2017-11-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15 N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

Unlikely remedy: fungicide clears infection from pathogenic fungus in larval southern leopard frogs (Lithobates sphenocephalus.

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Shane M Hanlon

Full Text Available Amphibians are often exposed to a wide variety of perturbations. Two of these, pesticides and pathogens, are linked to declines in both amphibian health and population viability. Many studies have examined the separate effects of such perturbations; however, few have examined the effects of simultaneous exposure of both to amphibians. In this study, we exposed larval southern leopard frog tadpoles (Lithobates sphenocephalus to the chytrid fungus Batrachochytrium dendrobatidis and the fungicide thiophanate-methyl (TM at 0.6 mg/L under laboratory conditions. The experiment was continued until all larvae completed metamorphosis or died. Overall, TM facilitated increases in tadpole mass and length. Additionally, individuals exposed to both TM and Bd were heavier and larger, compared to all other treatments. TM also cleared Bd in infected larvae. We conclude that TM affects larval anurans to facilitate growth and development while clearing Bd infection. Our findings highlight the need for more research into multiple perturbations, specifically pesticides and disease, to further promote amphibian heath.

Cryptococcus gattii fungemia: report of a case with lung and brain lesions mimicking radiological features of malignancy Fungemia por Cryptococcus gattii: relato de um caso com lesões cerebrais e pulmonares nos achados radiológicos mimetizando câncer

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Flávio de Mattos Oliveira

2007-08-01

Full Text Available A 64-year-old apparently immunocompetent white man developed lung and brain lesions of disseminated cryptococcosis. The radiologic features mimicked those of lung cancer metastatic to the central nervous system. C. gattii was recovered from cultures of bronchoalveolar lavage fluid, brain biopsy, and blood. The same fungus was recovered from pulmonary and brain specimens at autopsy. Serum and cerebrospinal fluid cryptococcal antigen tests were diagnostic in our case and should be included in the diagnostic evaluation of unexplained pulmonary and cerebral lesions. A literature search showed few reports of fungemia by this species of Cryptococcus, contrasting to C. neoformans.Homem branco de 64 anos, aparentemente imunocompetente, desenvolveu lesões pulmonares e cerebrais por criptococose disseminada. Os achados radiológicos foram similares àqueles encontrados em pacientes com câncer de pulmão e metástase no sistema nervoso central. C. gattii foi isolado de cultivos de lavado broncoalveolar, biópsia cerebral e sangue. O mesmo fungo foi encontrado em fragmentos pulmonares e cerebrais obtidos da autópsia. Testes de antígeno no soro e no líquido cefalorraquidiano foram diagnóstico no nosso caso e devem ser incluídos na avaliação diagnóstica de lesões pulmonares e cerebrais indefinidas. Pesquisa na literatura mostrou poucos relatos de fungemia por esta espécie de Cryptococcus, contrastando com C. neoformans.

Various Stages of Pink Fungus (Upasia salmonicolor in Java

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Ambarwati Harsojo Tjokrosoedarmo

1995-12-01

Full Text Available Pink fungus in Java is classified as Upasia salmonicolor (Basidiomycetes: Corticiaceae and its anamorph is Necator decretus. This fungus is a serious pathogen which attacks many woody plants. The pink fungus in Java exhibits five developmental stages on the surface of the host bark: I. An initial cobweb stage as thin, white, cobweb-like hyphal layer, which creeps over the surface of the bark, during which penetration of the host occurs; II. Pseudonodular stage, as conical white pustules occurring only on lenticels or cracks, and only on shady side of branches; III. Teleomorph, occurs as pink incrustation and pink pustules on shady side of branches; IV. Nodular stages, as globose white pustules occurring chiefly on intact bark, but also on the lenticels or cracks, on exposed side of branches; V. Anamorph, as small orange-red sporodochium, on exposed side of branches. Key words: pink fungus, Corticiaceae, Basidiomycetes, Necator

A vanillin derivative causes mitochondrial dysfunction and triggers oxidative stress in Cryptococcus neoformans.

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Kim, Jin Hyo; Lee, Han-Ok; Cho, Yong-Joon; Kim, Jeongmi; Chun, Jongsik; Choi, Jaehyuk; Lee, Younghoon; Jung, Won Hee

2014-01-01

Vanillin is a well-known food and cosmetic additive and has antioxidant and antimutagenic properties. It has also been suggested to have antifungal activity against major human pathogenic fungi, although it is not very effective. In this study, the antifungal activities of vanillin and 33 vanillin derivatives against the human fungal pathogen Cryptococcus neoformans, the main pathogen of cryptococcal meningitis in immunocompromised patients, were investigated. We found a structural correlation between the vanillin derivatives and antifungal activity, showing that the hydroxyl or alkoxy group is more advantageous than the halogenated or nitrated group in benzaldehyde. Among the vanillin derivatives with a hydroxyl or alkoxy group, o-vanillin and o-ethyl vanillin showed the highest antifungal activity against C. neoformans. o-Vanillin was further studied to understand the mechanism of antifungal action. We compared the transcriptome of C. neoformans cells untreated or treated with o-vanillin by using RNA sequencing and found that the compound caused mitochondrial dysfunction and triggered oxidative stress. These antifungal mechanisms of o-vanillin were experimentally confirmed by the significantly reduced growth of the mutants lacking the genes involved in mitochondrial functions and oxidative stress response.

Sexual Reproduction of Human Fungal Pathogens

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Heitman, Joseph; Carter, Dee A.; Dyer, Paul S.; Soll, David R.

2014-01-01

We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958

De Novo Transcriptome Analysis of Plant Pathogenic Fungus Myrothecium roridum and Identification of Genes Associated with Trichothecene Mycotoxin Biosynthesis

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Wei Ye

2017-02-01

Full Text Available Myrothecium roridum is a plant pathogenic fungus that infects different crops and decreases the yield of economical crops, including soybean, cotton, corn, pepper, and tomato. Until now, the pathogenic mechanism of M. roridum has remained unclear. Different types of trichothecene mycotoxins were isolated from M. roridum, and trichothecene was considered as a plant pathogenic factor of M. roridum. In this study, the transcriptome of M. roridum in different incubation durations was sequenced using an Illumina Hiseq 2000. A total of 35,485 transcripts and 25,996 unigenes for M. roridum were obtained from 8.0 Gb clean reads. The protein–protein network of the M. roridum transcriptome indicated that the mitogen-activated protein kinases signal pathway also played an important role in the pathogenicity of M. roridum. The genes related to trichothecene biosynthesis were annotated. The expression levels of these genes were also predicted and validated through quantitative real-time polymerase chain reaction. Tri5 gene encoding trichodiene synthase was cloned and expressed, and the purified trichodiene synthase was able to catalyze farnesyl pyrophosphate into different kinds of sesquiterpenoids.Tri4 and Tri11 genes were expressed in Escherichia coli, and their corresponding enzymatic properties were characterized. The phylogenetic tree of trichodiene synthase showed a great discrepancy between the trichodiene synthase from M. roridum and other species. Our study on the genes related to trichothecene biosynthesis establishes a foundation for the M. roridum hazard prevention, thus improving the yields of economical crops.

isolation and characterisation of cryptococcus neoformans

African Journals Online (AJOL)

2014-08-01

Aug 1, 2014 ... and Cryptococcus gattii from several environmental sites in Nairobi, Kenya .This could probably ... Globally, the risk of cryptococcal meningitis in HIV/. AIDS is estimated ..... gattii from the Amazon rainforest. PLoS One. 2013 ...

Cryptococcus laurentii fungaemia in a cervical cancer patient

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Rejane Pereira Neves

2015-11-01

Full Text Available Infections caused by emerging Cryptococcus non-neoformans species are being reported with increasingly frequency. Here, we present a case of fungaemia by Cryptococcus laurentii in a woman receiving aggressive immunosuppressive therapy for cervical neoplasia. Three venous blood samples were aseptically collected on consecutive days and C. laurentii was isolated and identified through phenotypic and molecular methods. After central venous catheter removal and appropriate antifungal therapy, the patient showed significant improvement and blood culture became negative. Thus, patients following immunosuppressive therapies and using invasive medical devices are at risk of C. laurentii blood infections.

Functional analysis of atfA gene to stress response in pathogenic thermal dimorphic fungus Penicillium marneffei.

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Panjaphorn Nimmanee

Full Text Available Penicillium marneffei, the pathogenic thermal dimorphic fungus is a causative agent of a fatal systemic disease, penicilliosis marneffei, in immunocompromised patients especially HIV patients. For growth and survival, this fungus has to adapt to environmental stresses outside and inside host cells and this adaptation requires stress signaling pathways and regulation of gene expression under various kinds of stresses. In this report, P. marneffei activating transcription factor (atfA gene encoding bZip-type transcription factor was characterized. To determine functions of this gene, atfA isogenic mutant strain was constructed using the modified split marker recombination method. The phenotypes and susceptibility to varieties of stresses including osmotic, oxidative, heat, UV, cell wall and cell membrane stresses of the mutant strain were compared with the wild type and the atfA complemented strains. Results demonstrated that the mRNA expression level of P. marneffei atfA gene increased under heat stress at 42°C. The atfA mutant was more sensitive to sodium dodecyl sulphate, amphotericin B and tert-butyl hydroperoxide than the wild type and complemented strains but not hydrogen peroxide, menadione, NaCl, sorbitol, calcofluor white, itraconazole, UV stresses and heat stress at 39°C. In addition, recovery of atfA mutant conidia after mouse and human macrophage infections was significantly decreased compared to those of wild type and complemented strains. These results indicated that the atfA gene was required by P. marneffei under specific stress conditions and might be necessary for fighting against host immune cells during the initiation of infection.

Antifungal susceptibilities of Cryptococcus neoformans.

Science.gov (United States)

Archibald, Lennox K; Tuohy, Marion J; Wilson, Deborah A; Nwanyanwu, Okey; Kazembe, Peter N; Tansuphasawadikul, Somsit; Eampokalap, Boonchuay; Chaovavanich, Achara; Reller, L Barth; Jarvis, William R; Hall, Gerri S; Procop, Gary W

2004-01-01

Susceptibility profiles of medically important fungi in less-developed countries remain uncharacterized. We measured the MICs of amphotericin B, 5-flucytosine, fluconazole, itraconazole, and ketoconazole for Cryptococcus neoformans clinical isolates from Thailand, Malawi, and the United States and found no evidence of resistance or MIC profile differences among the countries.

The components of rice and watermelon root exudates and their effects on pathogenic fungus and watermelon defense.

Science.gov (United States)

Ren, Lixuan; Huo, Hongwei; Zhang, Fang; Hao, Wenya; Xiao, Liang; Dong, Caixia; Xu, Guohua

2016-06-02

Watermelon (Citrullus lanatus) is susceptible to wilt disease caused by the fungus Fusarium oxysporum f. sp niveum (FON). Intercropping management of watermelon/aerobic rice (Oryza sativa) alleviates watermelon wilt disease, because some unidentified component(s) in rice root exudates suppress FON sporulation and spore germination. Here, we show that the phenolic acid p-coumaric acid is present in rice root exudates only, and it inhibits FON spore germination and sporulation. We found that exogenously applied p-coumaric acid up-regulated the expression of ClPR3 in roots, as well as increased chitinase activity in leaves. Furthermore, exogenously applied p-coumaric acid increased β-1,3-glucanase activity in watermelon roots. By contrast, we found that ferulic acid was secreted by watermelon roots, but not by rice roots, and that it stimulated spore germination and sporulation of FON. Exogenous application of ferulic acid down-regulated ClPR3 expression and inhibited chitinase activity in watermelon leaves. Salicylic acid was detected in both watermelon and rice root exudates, which stimulated FON spore germination at low concentrations and suppressed spore germination at high concentrations. Exogenously applied salicylic acid did not alter ClPR3 expression, but did increase chitinase and β-1,3-glucanase activities in watermelon leaves. Together, our results show that the root exudates of phenolic acids were different between rice and watermelon, which lead to their special ecological roles on pathogenic fungus and watermelon defense.

Two Rab5 Homologs Are Essential for the Development and Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

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Cheng D. Yang

2017-05-01

Full Text Available The rice blast fungus, Magnaporthe oryzae, infects many economically important cereal crops, particularly rice. It has emerged as an important model organism for studying the growth, development, and pathogenesis of filamentous fungi. RabGTPases are important molecular switches in regulation of intracellular membrane trafficking in all eukaryotes. MoRab5A and MoRab5B are Rab5 homologs in M. oryzae, but their functions in the fungal development and pathogenicity are unknown. In this study, we have employed a genetic approach and demonstrated that both MoRab5A and MoRab5B are crucial for vegetative growth and development, conidiogenesis, melanin synthesis, vacuole fusion, endocytosis, sexual reproduction, and plant pathogenesis in M. oryzae. Moreover, both MoRab5A and MoRab5B show similar localization in hyphae and conidia. To further investigate possible functional redundancy between MoRab5A and MoRab5B, we overexpressed MoRAB5A and MoRAB5B, respectively, in MoRab5B:RNAi and MoRab5A:RNAi strains, but neither could rescue each other’s defects caused by the RNAi. Taken together, we conclude that both MoRab5A and MoRab5B are necessary for the development and pathogenesis of the rice blast fungus, while they may function independently.

Meningoradiculitis due to Cryptococcus neofermans in an immunocompetent patient Meningorradiculite lombossacra causada por Cryptococcus neoformans em paciente imunocompetente

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Leonardo Deus-Silva

2004-03-01

Full Text Available Meningoradiculitis refers to combined involvement of meninges and nerve roots. The most frequent location is the lumbosacral region. Etiology is diverse, including inflammatory, infectious and neoplastic disorders. Meningoradiculitis is a rare form of involvement in cryptococcal infection. We describe a case of subacute lower limbs flaccid paresis diagnosed as lumbosacral meningoradiculitis in view of cerebrospinal fluid (CSF inflammatory changes and typical enhancement on MRI of lumbar spine. Cryptococcus neoformans was isolated from CSF. Extensive screening yielded no immunodeficiencies.Meningorradiculite refere-se ao envolvimento simultâneo das meninges e das raízes dos nervos. O local mais freqüentemente acometido é a região lombossacra. Patologias inflamatórias, infecciosas e neoplásicas são as causas mais freqüentes. Meningorradiculite é manifestação rara de infecção por Cryptococcus neoformans. Descrevemos um caso de paresia flácida dos membros inferiores, com diagnóstico de meningorradiculite lombossacra baseado nos achados clínicos, de ressonância magnética da coluna lombar e em alterações inflamatórias do líquido cefalorraqueano (LCR. Avaliação microbiológica do LCR revelou a presença de Cryptococcus neoformans e extensa investigação clínica e laboratorial excluiu imunodeficiências primárias e adquiridas.

Sexual reproduction and the evolution of microbial pathogens.

Science.gov (United States)

Heitman, Joseph

2006-09-05

Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.

Terbinafine inhibits Cryptococcus neoformans growth and modulates fungal morphology

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Caroline Rezende Guerra

2012-08-01

Full Text Available Cryptococcus neoformans is an encapsulated fungus that causes cryptococcosis. Central nervous system infection is the most common clinical presentation followed by pulmonary, skin and eye manifestations. Cryptococcosis is primarily treated with amphotericin B (AMB, fluconazole (FLC and itraconazole (ITC. In the present work, we evaluated the in vitro effect of terbinafine (TRB, an antifungal not commonly used to treat cryptococcosis. We specifically examined the effects of TRB, either alone or in conjunction with AMB, FLC and ITC, on clinical C. neoformans isolates, including some isolates resistant to AMB and ITC. Broth microdilution assays showed that TRB was the most effective drug in vitro. Antifungal combinations demonstrated synergism of TRB with AMB, FLC and ITC. The drug concentrations used for the combination formulations were as much as 32 and 16-fold lower than the minimum inhibitory concentration (MIC values of FLC and AMB alone, respectively. In addition, calcofluor white staining revealed the presence of true septa in hyphae structures that were generated after drug treatment. Ultrastructural analyses demonstrated several alterations in response to drug treatment, such as cell wall alterations, plasma membrane detachment, presence of several cytoplasmic vacuoles and mitochondrial swelling. Therefore, we believe that the use of TRB alone or in combination with AMB and azoles should be explored as an alternative treatment for cryptococcosis patients who do not respond to standard therapies.

Symbiotic Fungus of Marine Sponge Axinella sp. Producing Antibacterial Agent

Science.gov (United States)

Trianto, A.; Widyaningsih, S.; Radjasa, OK; Pribadi, R.

2017-02-01

The emerging of multidrug resistance pathogenic bacteria cause the treatment of the diseaseshave become ineffective. There for, invention of a new drug with novel mode of action is an essential for curing the disease caused by an MDR pathogen. Marine fungi is prolific source of bioactive compound that has not been well explored. This study aim to obtain the marine sponges-associated fungus that producing anti-MDR bacteria substaces. We collected the sponge from Riung water, NTT, Indonesia. The fungus was isolated with affixed method, followed with purification with streak method. The overlay and disk diffusion agar methods were applied for bioactivity test for the isolate and the extract, respectively. Molecular analysis was employed for identification of the isolate. The sponge was identified based on morphological and spicular analysis. The ovelay test showed that the isolate KN15-3 active against the MDR Staphylococcus aureus and Eschericia coli. The extract of the cultured KN15-3 was also inhibited the S. aureus and E. coli with inhibition zone 2.95 mm and 4.13 mm, respectively. Based on the molecular analysis, the fungus was identified as Aspergillus sydowii. While the sponge was identified as Axinella sp.

Genome sequencing and comparative genomics reveal a repertoire of putative pathogenicity genes in chilli anthracnose fungus Colletotrichum truncatum.

Science.gov (United States)

Rao, Soumya; Nandineni, Madhusudan R

2017-01-01

Colletotrichum truncatum, a major fungal phytopathogen, causes the anthracnose disease on an economically important spice crop chilli (Capsicum annuum), resulting in huge economic losses in tropical and sub-tropical countries. It follows a subcuticular intramural infection strategy on chilli with a short, asymptomatic, endophytic phase, which contrasts with the intracellular hemibiotrophic lifestyle adopted by most of the Colletotrichum species. However, little is known about the molecular determinants and the mechanism of pathogenicity in this fungus. A high quality whole genome sequence and gene annotation based on transcriptome data of an Indian isolate of C. truncatum from chilli has been obtained. Analysis of the genome sequence revealed a rich repertoire of pathogenicity genes in C. truncatum encoding secreted proteins, effectors, plant cell wall degrading enzymes, secondary metabolism associated proteins, with potential roles in the host-specific infection strategy, placing it next only to the Fusarium species. The size of genome assembly, number of predicted genes and some of the functional categories were similar to other sequenced Colletotrichum species. The comparative genomic analyses with other species and related fungi identified some unique genes and certain highly expanded gene families of CAZymes, proteases and secondary metabolism associated genes in the genome of C. truncatum. The draft genome assembly and functional annotation of potential pathogenicity genes of C. truncatum provide an important genomic resource for understanding the biology and lifestyle of this important phytopathogen and will pave the way for designing efficient disease control regimens.

Specialized Pathogen of a Social Insect

DEFF Research Database (Denmark)

Małagocka, Joanna

provide a game changing component that shapes the interaction in quite a unique way. This thesis explores some of the aspects of biology of host-pathogen interaction between red wood ants, F. polyctena, and the fungus P. formicae. First, the taxonomy of the fungus is studied and some nomenclatural issues...... that ants actively remove fungus-killed cadavers is documented and further explored in this thesis. I establish the effect of this behavior on raw numbers of cadavers present around an ant colony by detailed mapping of colony surroundings for three subsequent days, twice a day, three times during the season...

Cryptococcus gattii: Emergence in Western North America: Exploitation of a Novel Ecological Niche

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Kausik Datta

2009-01-01

Full Text Available The relatively uncommon fungal pathogen Cryptococcus gattii recently emerged as a significant cause of cryptococcal disease in human and animals in the Pacific Northwest of North America. Although genetic studies indicated its possible presence in the Pacific Northwest for more than 30 years, C. gattii as an etiological agent was largely unknown in this region prior to 1999. The recent emergence may have been encouraged by changing conditions of climate or land use and/or host susceptibility, and predictive ecological niche modeling indicates a potentially wider spread. C. gattii can survive wide climatic variations and colonize the environment in tropical, subtropical, temperate, and dry climates. Long-term climate changes, such as the significantly elevated global temperature in the last 100 years, influence patterns of disease among plants and animals and create niche microclimates habitable by emerging pathogens. C. gattii may have exploited such a hitherto unrecognized but clement environment in the Pacific Northwest to provide a wider exposure and risk of infection to human and animal populations.

In vitro antifungal activity of fatty acid methyl esters of the seeds of Annona cornifolia A.St.-Hil. (Annonaceae) against pathogenic fungus Paracoccidioides brasiliensis.

Science.gov (United States)

Lima, Luciana Alves Rodrigues dos Santos; Johann, Susana; Cisalpino, Patrícia Silva; Pimenta, Lúcia Pinheiro Santos; Boaventura, Maria Amélia Diamantino

2011-01-01

Fatty acids are abundant in vegetable oils. They are known to have antibacterial and antifungal properties. Antifungal susceptibility was evaluated by broth microdilution assay following CLSI (formerly the NCCLS) guidelines against 16 fungal strains of clinical interest. In this work, fatty acid methyl esters (FAME) was able to inhibit 12 clinical strains of the pathogenic fungus Paracoccidioides brasiliensis and were also active in the bioautographic assay against Cladosporium sphaerospermum. FAME was a more potent antifungal than trimethoprim-sulfamethoxazole against P. brasiliensis under the experimental conditions tested.

Infection of silkworm larvae by the entomopathogenic fungus Metarhizium anisopliae

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Lucineia de Fátima Chasko Ribeiro

Full Text Available ABSTRACT: The isolate E9 of Metarhizium anisopliae was used in commercial hybrids of Bombyx mori larvae to evaluate its biological effect. Symptomatological analyses showed typical signs of fungal infection. Histopathology revealed the presence of large numbers of hemocytes in the hemocoel, and on the sixth dpi the bodies of the insects appeared to be colonised by the fungus. The isolate E9 is pathogenic to larvae B. mori and; therefore, death of the insects was caused by the colonization of fungus in the epidermal and mesodermal tissues.

THE INFLUENCE OF ULTRAVIOLET LIGHT ON PATHOGENICITY OF ENTOMOPATHOGENIC FUNGUS BEAUVERIA BASSIANA (BALSAMO VUILLEMIN TO THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS HBN. (LEPIDOPTERA: CRAMBIDAE

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L Cagán

2002-05-01

Full Text Available The influence of different doses of ultraviolet (UV light on the pathogenicity of entomopathogenic fungus Beauveria bassiana (Balsamo Vuillemin to the European corn borer, Ostrinia nubilalis Hbn., and radial growth of fungus was studied in laboratory conditions. The suspensions of B. bassiana isolate SK99 were exposed to UV light. Four different doses of UV light were used in the experiment. The distance between exposed suspensions and UV light source was 0.3 m. Exposure duration was 15, 30, 45 and 60 minutes (as A, B, C and D variants. Control variant SK99 and obtained variants SK99A, SK99B, SK99C and SK99D were cultivated 21 days on Sabourard-dextrose agar. The larvae of O. nubilalis were infected with dry powder consisted of mycelia and spores from fungus cultures. During 10 days, the mortality of infected larvae was evaluated. It was ascertained that UV light exposition significantly influenced the mortality effect of B. bassiana isolates to O. nubilalis larvae. Variant SK99C showed the highest level of infectivity. Radial growth of UV variants was slower with rising time of exposure. The best ability to grow possessed non-irradiated isolate SK99 and the worse variant SK99D. The difference between these two variants was significant.

Susceptibility testing of Cryptococcus diffluens against amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole and posaconazole

NARCIS (Netherlands)

Kantarcioglu, A.S.; Boekhout, T.; Yucel, A.; Altas, K.

2009-01-01

Cryptococcus diffluens is a recently re-established species that shares several phenotypic features with Cryptococcus neoformans. We evaluated the application of the Clinical Laboratory Standards Institute (CLSI, formerly NCCLS) macro- and microbroth dilution methods and the E-test agar diffusion

Genome-Wide Identification of circRNAs in Pathogenic Basidiomycetous Yeast Cryptococcus neoformans Suggests Conserved circRNA Host Genes over Kingdoms

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Liang Huo

2018-02-01

Full Text Available Circular RNAs (circRNAs, a novel class of ubiquitous and intriguing noncoding RNA, have been found in a number of eukaryotes but not yet basidiomycetes. In this study, we identified 73 circRNAs from 39.28 million filtered RNA reads from the basidiomycete Cryptococcus neoformans JEC21 using next-generation sequencing (NGS and the bioinformatics tool circular RNA identification (CIRI. Furthermore, mapping of newly found circRNAs to the genome showed that 73.97% of the circRNAs originated from exonic regions, whereas 20.55% were from intergenic regions and 5.48% were from intronic regions. Enrichment analysis of circRNA host genes was conducted based on the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway databases. The results reveal that host genes are mainly responsible for primary metabolism and, interestingly, ribosomal protein production. Furthermore, we uncovered a high-level circRNA that was a transcript from the guanosine triphosphate (GTPase gene CNM01190 (gene ID: 3255052 in our yeast. Coincidentally, YPT5, CNM01190′s ortholog of the GTPase in Schizosaccharomyces pombe, protists, and humans, has already been proven to generate circRNAs. Additionally, overexpression of RNA debranching enzyme DBR1 had varied influence on the expression of circRNAs, indicating that multiple circRNA biosynthesis pathways exist in C. neoformans. Our study provides evidence for the existence of stable circRNAs in the opportunistic human pathogen C. neoformans and raises a question regarding their role related to pathogenesis in this yeast.

Differentiation of the emerging human pathogens Trichosporon asahii and Trichosporon asteroides from other pathogenic yeasts and moulds by using species-specific monoclonal antibodies.

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Genna E Davies

Full Text Available The fungal genus Trichosporon contains emerging opportunistic pathogens of humans, and is the third most commonly isolated non-candidal yeast from humans. Trichosporon asahii and T. asteroides are the most important species causing disseminated disease in immunocompromised patients, while inhalation of T. asahii spores is the most important cause of summer-type hypersensitivity pneumonitis in healthy individuals. Trichosporonosis is misdiagnosed as candidiasis or cryptococcosis due to a lack of awareness and the ambiguity of diagnostic tests for these pathogens. In this study, hybridoma technology was used to produce two murine monoclonal antibodies (MAbs, CA7 and TH1, for detection and differentiation of Trichosporon from other human pathogenic yeasts and moulds. The MAbs react with extracellular antigens from T. asahii and T. asteroides, but do not recognise other related Trichosporon spp., or unrelated pathogenic yeasts and moulds including Candida, Cryptococcus, Aspergillus, Fusarium, and Scedosporium spp., or the etiologic agents of mucormycosis. Immunofluorescence and Western blotting studies show that MAb CA7, an immunoglobulin G1 (IgG1, binds to a major 60 kDa glycoprotein antigen produced on the surface of hyphae, while TH1, an immunoglobulin M (IgM, binds to an antigen produced on the surface of conidia. The MAbs were used in combination with a standard mycological growth medium (Sabouraud Dextrose Agar to develop an enzyme-linked immunosorbent assay (ELISA for differentiation of T. asahii from Candida albicans and Cryptococcus neoformans in single and mixed species cultures. The MAbs represent a major advance in the identification of T. asahii and T. asteroides using standard mycological identification methods.

Identification of genes expressed by Cryptococcus gattii during iron deprivation

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Daphine Ariadne Jesus de Paula

2014-09-01

Full Text Available Cryptococcus neoformans and C. gattii are pathogenic yeasts that cause life-threatening diseases in humans and animals. Iron is an essential nutrient for virtually every organism as it functions as a cofactor in numerous essential enzymatic reactions. In the literature, the competition for iron between microbes and mammalian hosts during infection is well documented. In this study, we used representational difference analysis (RDA in order to gain a better understanding of how C. gattii responds to iron starvation. A total of 15 and 29 genes were identified as having altered expression levels due to iron depletion after 3 h and 12 h, respectively. Of these, eight genes were identified in both libraries. The transcripts were related to many biological processes, such as cell cycle, ergosterol metabolism, cell wall organization, transportation, translation, cell respiration and the stress response. These data suggest a remodeling of C. gattii metabolism during conditions of iron deprivation.

Antifungal and Anti-Biofilm Activity of Essential Oil Active Components against Cryptococcus neoformans and Cryptococcus laurentii

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Poonam Kumari

2017-11-01

Full Text Available Cryptococcosis is an emerging and recalcitrant systemic infection occurring in immunocompromised patients. This invasive fungal infection is difficult to treat due to the ability of Cryptococcus neoformans and Cryptococcus laurentii to form biofilms resistant to standard antifungal treatment. The toxicity concern of these drugs has stimulated the search for natural therapeutic alternatives. Essential oil and their active components (EO-ACs have shown to possess the variety of biological and pharmacological properties. In the present investigation the effect of six (EO-ACs sourced from Oregano oil (Carvacrol, Cinnamon oil (Cinnamaldehyde, Lemongrass oil (Citral, Clove oil (Eugenol, Peppermint oil (Menthol and Thyme oil (thymol against three infectious forms; planktonic cells, biofilm formation and preformed biofilm of C. neoformans and C. laurentii were evaluated as compared to standard drugs. Data showed that antibiofilm activity of the tested EO-ACs were in the order: thymol>carvacrol>citral>eugenol=cinnamaldehyde>menthol respectively. The three most potent EO-ACs, thymol, carvacrol, and citral showed excellent antibiofilm activity at a much lower concentration against C. laurentii in comparison to C. neoformans indicating the resistant nature of the latter. Effect of the potent EO-ACs on the biofilm morphology was visualized using scanning electron microscopy (SEM and confocal laser scanning microscopy (CLSM, which revealed the absence of extracellular polymeric matrix (EPM, reduction in cellular density and alteration in the surface morphology of biofilm cells. Further, to realize the efficacy of the EO-ACs in terms of human safety, cytotoxicity assays and co-culture model were evaluated. Thymol and carvacrol as compared to citral were the most efficient in terms of human safety in keratinocyte- Cryptococcus sp. co-culture infection model suggesting that these two can be further exploited as cost-effective and non-toxic anti

Cryptococcus gattii urease as a virulence factor and the relevance of enzymatic activity in cryptococcosis pathogenesis.

Science.gov (United States)

Feder, Vanessa; Kmetzsch, Lívia; Staats, Charley Christian; Vidal-Figueiredo, Natalia; Ligabue-Braun, Rodrigo; Carlini, Célia Regina; Vainstein, Marilene Henning

2015-04-01

Ureases (EC 3.5.1.5) are Ni(2+) -dependent metalloenzymes produced by plants, fungi and bacteria that hydrolyze urea to produce ammonia and CO2 . The insertion of nickel atoms into the apo-urease is better characterized in bacteria, and requires at least three accessory proteins: UreD, UreF, and UreG. Our group has demonstrated that ureases possess ureolytic activity-independent biological properties that could contribute to the pathogenicity of urease-producing microorganisms. The presence of urease in pathogenic bacteria strongly correlates with pathogenesis in some human diseases. Some medically important fungi also produce urease, including Cryptococcus neoformans and Cryptococcus gattii. C. gattii is an etiological agent of cryptococcosis, most often affecting immunocompetent individuals. The cryptococcal urease might play an important role in pathogenesis. It has been proposed that ammonia produced via urease action might damage the host endothelium, which would enable yeast transmigration towards the central nervous system. To analyze the role of urease as a virulence factor in C. gattii, we constructed knockout mutants for the structural urease-coding gene URE1 and for genes that code the accessory proteins Ure4 and Ure6. All knockout mutants showed reduced multiplication within macrophages. In intranasally infected mice, the ure1Δ (lacking urease protein) and ure4Δ (enzymatically inactive apo-urease) mutants caused reduced blood burdens and a delayed time of death, whereas the ure6Δ (enzymatically inactive apo-urease) mutant showed time and dose dependency with regard to fungal burden. Our results suggest that C. gattii urease plays an important role in virulence, in part possibly through enzyme activity-independent mechanism(s). © 2015 FEBS.

Equine nasopharyngeal cryptococcoma due to Cryptococcus gattii

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Raquel Aparecida Sales da Cruz

2017-08-01

Full Text Available ABSTRACT: Cryptococcus gattii is often associated with pulmonary and systemic infections in humans and animals. In this research we report a case of nasopharyngeal cryptococoma caused by C. gatti in an equine. A 10-year-old mare presented a mass obstructing the oropharynx. Macroscopically the mass was asymmetric, and was attached to the ethmoidal sinuses and obstructed the oropharynx. Histopathological examination of the mass revealed multiple yeast cells ranging from spherical to oval, 4-8μm in diameter, with some of them showing narrow base polar budding. Cryptococcus gattii growth in mycological culture (Sabouraud Dextrose Agar and was L-canavanine-glycine-bromothymol blue Agar positive. The molecular identification confirmed the isolate as C. gattii by means of the amplification of universal primers. C. gattii is considered an emerging fungal agent, as it affects human and animals and does not respond efficiently to commonly established treatments.

Ultrastructural and chemotaxonomic analysis of a xylanolytic strain of Cryptococcus adeliensis isolated from sheep droppings in Spain.

Science.gov (United States)

Velázquez, Encarna; del Villar, María; Grondona, Isabel; Monte, Enrique; González-Villa, Tomás

2006-09-01

Cryptococcus adeliensis was initially described as a psycrophilic species containing a single strain CBS 8351(T) isolated from decayed algae in Terre Adelie (Antartida). Later, a second strain of this species was isolated from an immunosuppressed patient affected by leukaemia in Germany and recently several strains from this species have been found in human patients and pigeon droppings of the same country. In this study, we isolated from sheep droppings in Spain a xylanolytic strain named LEVX01 that was phenotypically related to the strain CBS 8351(T) and showed a 100% similarity in the D1/D2 domain and 5.8S-ITS region sequences with respect to the remaining described strains of C. adeliensis. These findings suggest that this species has a wide geographical distribution and that the animal faeces are a common habitat for C. adeliensis. The chemotaxonomic analyses showed the absence of detectable amounts of xylose in the cell walls of the strains LEVX01 and CBS8351(T) in contrast to other Cryptococcus species. Interestingly, the ultrastructural study showed the presence of fimbriae in these two strains that could be involved in the attachment to the host cells and, as occurs in Candida albicans, they could also be a pathogenicity factor for the man.

Furfural from Pine Needle Extract Inhibits the Growth of a Plant Pathogenic Fungus, Alternaria mali

Science.gov (United States)

Yoo, Sun Kyun; Moon, Sung-Kwon; Lee, Ung-Soo

2007-01-01

The antifungal effect of pine needle extract prepared by a distinguishable extraction method and the dry distillation method, was examined. The effect of this extract itself was insignificant. The chemical components of pine needle extract were then investigated by gas chromatographic analysis, and four chemical components, acetol, furfural, 5-methyl furfural, and terpine-4-ol, were identified. The antifungal effects of those four chemical components against Alternaria mali (A. mali), an agent of Alternaria blotch of apple, were then examined. It was observed that the minimum inhibitory concentrations (MICs) were 6.25, 0.78, 0.78, and 12.5 (mg/ml) of acetol, furfural, 5-methyl furfural, and terpine-4-ol, respectively. MICs of furfural and 5-methyl furfural had the same order of magnitude as that of an antifungal agrochemical, chlorothalonil. Although furfural itself can not be completely substituted for an antifungal agrochemical, a partial mixture of furfural and antifungal agrochemical may be used as a substitute. The use of agrochemicals for the prevention of plant disease caused by pathogenic fungus such as A. mali could be partially reduced by the application of this mixture. PMID:24015067

Somaclonal variation of sugar beet resistant to pathogenic root rot Fusarium oxysporum var. orthoceras

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Urazaliev Kairat

2013-01-01

Full Text Available Sugar beet (Beta vulgaris L. - one of the most important crop in the world. In Kazakhstan, it is a traditional and major source of domestic sugar. The industry of cultivation and production of sugar beet is one of the priority areas of agricultural development of the country. In this paper, we studied the regeneration ability of different genotypes of sugar beet explants on selective media with the culture filtrate of the pathogen fungus F. oxysporum var. orthoceras. From the roots and shoots of sugar beet the pathogen Fusarium root rot was isolated. Was obtained pure cultures of the isolated pathogen. As a result, of morphological and cultural descriptions, as well as microbiological analysis it was revealed that the isolated pathogen is Fusarium Oxysporum. The results showed the pathogenicity of the fungus. For regeneration in vitro of the sugar beet genotypes resistant to the pathogen the culture media was optimized to the culture filtrate of the fungus F. oxysporum var. orthoceras. The frequency of shoot regeneration, depending on the genotype, was 1,0-12,5 %. On these explants the multiple shoot formations were observed.

Pathogenicity and fungicide sensitivity of the causal agent of ...

African Journals Online (AJOL)

The pathogenicity of the fungus and its cross-infection potential were determined on mango, avocado, papaya and banana fruits. The sensitivity of the pathogen to fungicides was determined by assessing radial mycelial growth on potato dextrose agar (PDA) amended with nine different fungicides (Bendazim, Funguran, ...

Cryptococcus neoformans Is Internalized by Receptor-Mediated or ‘Triggered’ Phagocytosis, Dependent on Actin Recruitment

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Guerra, Caroline Rezende; Seabra, Sergio Henrique; de Souza, Wanderley; Rozental, Sonia

2014-01-01

Cryptococcosis by the encapsulated yeast Cryptococcus neoformans affects mostly immunocompromised individuals and is a frequent neurological complication in AIDS patients. Recent studies support the idea that intracellular survival of Cryptococcus yeast cells is important for the pathogenesis of cryptococcosis. However, the initial steps of Cryptococcus internalization by host cells remain poorly understood. Here, we investigate the mechanism of Cryptococcus neoformans phagocytosis by peritoneal macrophages using confocal and electron microscopy techniques, as well as flow cytometry quantification, evaluating the importance of fungal capsule production and of host cell cytoskeletal elements for fungal phagocytosis. Electron microscopy analyses revealed that capsular and acapsular strains of C. neoformans are internalized by macrophages via both ‘zipper’ (receptor-mediated) and ‘trigger’ (membrane ruffle-dependent) phagocytosis mechanisms. Actin filaments surrounded phagosomes of capsular and acapsular yeasts, and the actin depolymerizing drugs cytochalasin D and latrunculin B inhibited yeast internalization and actin recruitment to the phagosome area. In contrast, nocodazole and paclitaxel, inhibitors of microtubule dynamics decreased internalization but did not prevent actin recruitment to the site of phagocytosis. Our results show that different uptake mechanisms, dependent on both actin and tubulin dynamics occur during yeast internalization by macrophages, and that capsule production does not affect the mode of Cryptococcus uptake by host cells. PMID:24586631

Transcriptome of an entomophthoralean fungus (Pandora formicae) shows molecular machinery adjusted for successful host exploitation and transmission

DEFF Research Database (Denmark)

Malagocka, Joanna; Grell, Morten Nedergaard; Lange, Lene

2015-01-01

Pandora formicae is an obligate entomopathogenic fungus from the phylum Entomophthoromycota, known to infect only ants from the genus Formica. In the final stages of infection, the fungus induces the so-called summit disease syndrome, manipulating the host to climb up vegetation prior to death......, but the fungus had not grown out through the cuticle and (2) when the fungus was growing out from host cadaver and producing spores. These phases mark the switch from within-host growth to reproduction on the host surface, after fungus outgrowth through host integument. In this first de novo transcriptome...... of an entomophthoralean fungus, we detected expression of many pathogenicity-related genes, including secreted hydrolytic enzymes and genes related to morphological reorganization and nutrition uptake. Differences in expression of genes in these two infection phases were compared and showed a switch in enzyme expression...

Long-term survival of Cryptococcus neoformans and Cryptococcus gattii in stored environmental samples from Colombia.

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Escandón, Patricia; Castañeda, Elizabeth

2015-01-01

Both Cryptococcus neoformans and Cryptococcus gattii have been isolated from a variety of environmental sources in Colombia. To determine the viability of C. neoformans/C. gattii isolates in stored soil samples, filtrates and bird droppings from which these yeasts were previously recovered. A total of 964 samples collected between 2003 and 2009, and kept at room temperature were processed. From them, 653 samples were from trees decaying wood, 274 from soil filtrates and 37 from bird droppings. When C. neoformans or C. gattii were recovered, the molecular type of each isolate was established by PCR fingerprinting using the single primer (GTG)5. Among the processed samples, 161 isolates were recovered. From those, 81 (50.3%) corresponded to C. gattii recovered from decaying wood of Eucalyptus spp., Corymbia ficifolia, Terminalia catappa and Ficus spp. trees, and 80 (49.7%) corresponded to C. neoformans recovered from Ficus spp. and eucalyptus trees, as well as from bird droppings. The most prevalent molecular type among the C. gattii and C. neoformans isolates was VGII and VNI, respectively. The re-isolation of C. neoformans/C. gattii from 10-year stored samples suggests that these yeasts are able to keep viable in naturally colonized samples. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Cryptococcus neoformans var neoformans isolated from droppings of captive birds in Nigeria.

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Irokanulo, E O; Makinde, A A; Akuesgi, C O; Ekwonu, M

1997-04-01

The yeast, Cryptococcus neoformans, was found in apparently healthy birds at the Jos Wildlife Park and Zoo in Jos, Nigeria. Cryptococcus neoformans var neoformans was isolated from feces of four captive bird species. Five isolates belonged to serotype A while two were serotype D. Serotype A of C. neoformans was isolated from a white face duck (Dendrocygna viduata), eagle owl (Bubo africanus cinerascene) and peacock (Pavo cristatus). The other two (serotype D), were isolated from a spotted eagle owl.

HapX positively and negatively regulates the transcriptional response to iron deprivation in Cryptococcus neoformans.

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Won Hee Jung

2010-11-01

Full Text Available The fungal pathogen Cryptococcus neoformans is a major cause of illness in immunocompromised individuals such as AIDS patients. The ability of the fungus to acquire nutrients during proliferation in host tissue and the ability to elaborate a polysaccharide capsule are critical determinants of disease outcome. We previously showed that the GATA factor, Cir1, is a major regulator both of the iron uptake functions needed for growth in host tissue and the key virulence factors such as capsule, melanin and growth at 37°C. We are interested in further defining the mechanisms of iron acquisition from inorganic and host-derived iron sources with the goal of understanding the nutritional adaptation of C. neoformans to the host environment. In this study, we investigated the roles of the HAP3 and HAPX genes in iron utilization and virulence. As in other fungi, the C. neoformans Hap proteins negatively influence the expression of genes encoding respiratory and TCA cycle functions under low-iron conditions. However, we also found that HapX plays both positive and negative roles in the regulation of gene expression, including a positive regulatory role in siderophore transporter expression. In addition, HapX also positively regulated the expression of the CIR1 transcript. This situation is in contrast to the negative regulation by HapX of genes encoding GATA iron regulatory factors in Aspergillus nidulans and Schizosaccharomyces pombe. Although both hapX and hap3 mutants were defective in heme utilization in culture, only HapX made a contribution to virulence, and loss of HapX in a strain lacking the high-affinity iron uptake system did not cause further attenuation of disease. Therefore, HapX appears to have a minimal role during infection of mammalian hosts and instead may be an important regulator of environmental iron uptake functions. Overall, these results indicated that C. neoformans employs multiple strategies for iron acquisition during infection.

Production of an antimicrobial substance against Cryptococcus neoformans by Paenibacillus brasilensis Sa3 isolated from the rhizosphere of Kalanchoe brasiliensis.

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Fortes, Tiago Oliveira; Alviano, Daniela Sales; Tupinambá, Gleiser; Padrón, Thaís Souto; Antoniolli, Angelo Roberto; Alviano, Celuta Sales; Seldin, Lucy

2008-01-01

An antifungal substance produced by Paenibacillus brasilensis strain Sa3 was preliminary characterized and showed to be stable after treatment with different enzymes and organic solvents and at a wide range of pH, and presented a molecular weight between 3 and 10 kDa. In vitro antagonism of this strain towards Cryptococcus neoformans was investigated by optical and electronic microscopic analyses and a fungicidal effect on C. neoformans was observed. Ultrastructural analysis showed intense changes on the fungus when it was paired cultured with strain Sa3, mainly the detachment of the capsule from the cell wall and the presence of altered organelles in the cytoplasm. This novel antifungal substance produced by P. brasilensis Sa3 may represent a new insight in antifungal therapy mainly against emergent fungi. Also, prospective studies on rhizobacteria of plants as Kalanchoe brasiliensis may offer a potential source for the discovery of bioactive compounds with medical value.

Characterization of the antigenicity of Cpl1, a surface protein of Cryptococcus neoformans var. neoformans.

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Cai, Jian-Piao; Liu, Ling-Li; To, Kelvin K W; Lau, Candy C Y; Woo, Patrick C Y; Lau, Susanna K P; Guo, Yong-Hui; Ngan, Antonio H Y; Che, Xiao-Yan; Yuen, Kwok-Yung

2015-01-01

Cryptococcus neoformans var. neoformans is an important fungal pathogen. The capsule is a well established virulence factor and a target site for diagnostic tests. The CPL1 gene is required for capsular formation and virulence. The protein product Cpl1 has been proposed to be a secreted protein, but the characteristics of this protein have not been reported. Here we sought to characterize Cpl1. Phylogenetic analysis showed that the Cpl1 of C. neoformans var. neoformans and the Cpl1 orthologs identified in C. neoformans var. grubii and C. gattii formed a distinct cluster among related fungi; while the putative ortholog found in Trichosporon asahii was distantly related to the Cryptococcus cluster. We expressed Cpl1 abundantly as a secreted His-tagged protein in Pichia pastoris. The protein was used to immunize guinea pigs and rabbits for high titer mono-specific polyclonal antibody that was shown to be highly specific against the cell wall of C. neoformans var. neoformans and did not cross react with C. gattii, T. asahii, Aspergillus spp., Candida spp. and Penicillium spp. Using the anti-Cpl1 antibody, we detected Cpl1 protein in the fresh culture supernatant of C. neoformans var. neoformans and we showed by immunostaining that the Cpl1 protein was located on the surface. The Cpl1 protein is a specific surface protein of C. neoformans var. neoformans. © 2015 by The Mycological Society of America.

Species-specific chitin-binding module 18 expansion in the amphibian pathogen Batrachochytrium dendrobatidis.

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Abramyan, John; Stajich, Jason E

2012-01-01

Batrachochytrium dendrobatidis is the causative agent of chytridiomycosis, which is considered one of the driving forces behind the worldwide decline in populations of amphibians. As a member of the phylum Chytridiomycota, B. dendrobatidis has diverged significantly to emerge as the only pathogen of adult vertebrates. Such shifts in lifestyle are generally accompanied by various degrees of genomic modifications, yet neither its mode of pathogenicity nor any factors associated with it have ever been identified. Presented here is the identification and characterization of a unique expansion of the carbohydrate-binding module family 18 (CBM18), specific to B. dendrobatidis. CBM (chitin-binding module) expansions have been likened to the evolution of pathogenicity in a variety of fungus species, making this expanded group a prime candidate for the identification of potential pathogenicity factors. Furthermore, the CBM18 expansions are confined to three categories of genes, each having been previously implicated in host-pathogen interactions. These correlations highlight this specific domain expansion as a potential key player in the mode of pathogenicity in this unique fungus. The expansion of CBM18 in B. dendrobatidis is exceptional in its size and diversity compared to other pathogenic species of fungi, making this genomic feature unique in an evolutionary context as well as in pathogenicity. Amphibian populations are declining worldwide at an unprecedented rate. Although various factors are thought to contribute to this phenomenon, chytridiomycosis has been identified as one of the leading causes. This deadly fungal disease is cause by Batrachochytrium dendrobatidis, a chytrid fungus species unique in its pathogenicity and, furthermore, its specificity to amphibians. Despite more than two decades of research, the biology of this fungus species and its deadly interaction with amphibians had been notoriously difficult to unravel. Due to the alarming rate of worldwide

Is Climate influencing Cryptococcus gattii on Vancouver Island?

Centers for Disease Control (CDC) Podcasts

2016-03-24

Dr. Christopher Uejio, Department of Geography and Program in Public Health, Florida State University, discusses Cryptococcus gattii on Vancouver Island.  Created: 3/24/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 3/24/2016.

Growth in rice cells requires de novo purine biosynthesis by the blast fungus Magnaporthe oryzae

Science.gov (United States)

Fernandez, Jessie; Yang, Kuan Ting; Cornwell, Kathryn M.; Wright, Janet D.; Wilson, Richard A.

2013-01-01

Increasing incidences of human disease, crop destruction and ecosystem perturbations are attributable to fungi and threaten socioeconomic progress and food security on a global scale. The blast fungus Magnaporthe oryzae is the most devastating pathogen of cultivated rice, but its metabolic requirements in the host are unclear. Here we report that a purine-requiring mutant of M. oryzae could develop functional appressoria, penetrate host cells and undergo the morphogenetic transition to elaborate bulbous invasive hyphae from primary hyphae, but further in planta growth was aborted. Invasive hyphal growth following rice cell ingress is thus dependent on de novo purine biosynthesis by the pathogen and, moreover, plant sources of purines are neither available to the mutant nor required by the wild type during the early biotrophic phase of infection. This work provides new knowledge about the metabolic interface between fungus and host that might be applicable to other important intracellular fungal pathogens. PMID:23928947

Patogenicidade de Beauveria bassiana ao psilídeo Diaphorina citri e compatibilidade do fungo com produtos fitossanitários Beauveria bassiana pathogenicity to Diaphorina citri and compatibility of the fungus with phytosanitary products

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Ana Paula Ferreira Pinto

2012-12-01

Full Text Available O objetivo deste trabalho foi avaliar a patogenicidade de Beauveria bassiana a ninfas de Diaphorina citri (Hemiptera: Psyllidae e verificar a compatibilidade do fungo com produtos fitossanitários e sua persistência em plantas de citros. Ninfas de D. citri foram pulverizadas com B. bassiana, nas concentrações 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 e 1x10(9 conídios mL-1, para determinação da concentração letal. Para avaliação da compatibilidade do fungo com produtos fitossanitários, extrato de nim e cinco inseticidas de quatro grupos químicos diferentes foram incorporados individualmente ao meio de cultura BDA em que o fungo foi cultivado. Avaliaram-se o crescimento vegetativo, a esporulação e a viabilidade do entomopatógeno. Plantas de citros, mantidas em casa de vegetação, foram tratadas primeiramente com os produtos fitossanitários e depois com o entomopatógeno. Avaliaram-se os tempos de exposição de 24 horas e de 7 e 14 dias. O fungo foi patogênico às ninfas de D. citri; a CL50 foi de 0,4x10(7 e a CL90 de 6,7x10(7 conidios mL-1, no décimo dia de avaliação. Em laboratório, os produtos fitosssanitários reduzem o crescimento do fungo. Em casa de vegetação, os produtos não afetam a sobrevivência do fungo nas plantas de citros.The objective of this work was to evaluate the pathogenicity of Beauveria bassiana to Diaphorina citri (Hemiptera: Psyllidae nymphs, and to check the compatibility of the fungus with phytosanitary products, and its persistence in citrus plants. Nymphs of D. citri were sprayed with B. bassiana in the concentrations 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 and 1x10(9 conidia mL-1 for lethal concentration determination. In order to evaluate the compatibility of the phytosanitary products with the fungus, neem extract and five insecticides of four different chemical groups were individually added to PDA culture medium, in which the fungus was cultivated. Vegetative growth, sporulation and viability

Extracellular glycosylphosphatidylinositol-anchored mannoproteins and proteases of Cryptococcus neoformans.

Science.gov (United States)

Eigenheer, Richard A; Jin Lee, Young; Blumwald, Eduardo; Phinney, Brett S; Gelli, Angie

2007-06-01

Extracellular proteins of Cryptococcus neoformans are involved in the pathogenesis of cryptococcosis, and some are immunoreactive antigens that may potentially serve as candidates for vaccine development. To further study the extracellular proteome of the human fungal pathogen Cry. neoformans, we conducted a proteomic analysis of secreted and cell wall-bound proteins with an acapsular strain of Cry. neoformans. Proteins were identified from both intact cells and cell walls. In both cases, extracellular proteins were removed with trypsin or beta-glucanase, and then all proteins/peptides were purified by solid-phase extraction, spin dialysis, and HPLC, and identified by liquid chromatography-mass spectrometry. This study identified 29 extracellular proteins with a predicted N-terminal signal sequence and also a predicted glycosylphosphatidylinositol anchor motif in more than half. Among the novel proteins identified were five glycosylphosphatidylinositol-anchored proteins with extensive Ser/Thr-rich regions but no apparent functional domains, a glycosylphosphatidylinositol-anchored aspartic protease, and a metalloprotease with structural similarity to an elastinolytic metalloprotease of Aspergillus fumigatus. This study suggests that Cry. neoformans has the machinery required to target glycosylphosphatidylinositol-anchored proteins to the cell wall, and it confirms the extracellular proteolytic ability of Cry. neoformans.

Susceptibilidad "in vitro" de cepas de Cryptococcus a 5 drogas antifungicas "In vitro" susceptibility of Cryptococcus strains to 5 antifungal drugs

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A. J. Bava

1989-10-01

Full Text Available Se estudió la susceptibilidad "in vitro" de 24 cepas de 3 especies del género Cryptococcus a 5 drogas antifúngicas (anfotericina B, 5 fluorocitosina, ketoconazol, itraconazol y miconazol. Las mismas se agruparon según su especie, variedad y origen de aislamiento. Para determinar la concentración inhibitoria mínima (C.I.M. de cada droga se empleó el método de dilución en agar con el medio básico nitrogenado para levaduras, adicionado de glucosa. Se obtuvo además la media geométrica de estos valores para cada grupo y se comparó cada uno de ellos. Los resultados obtenidos fueron homogéneos con la sola excepción de las cepas de Cryptococcus sp (no neoformans, en las cuales se detectaron elevados valores de C.I.M. para la 5 fluorocitosina.A comparative study of the "in vitro" susceptibility of 24 Cryptococcus strains to 5 antifungal drugs (amphotericin B, 5 fluorocytosine, miconazole, itraconazole and ketoconazole, was carried out. These strains were grouped according to species, varieties and isolation's origins. The minimum inhibitory concentration (M.I.C. was determinated by the agar dilution technique in yeast nitrogen base agar with dextrose. The mean geometrical of the M.I.C. values of each group was compared with the others. The results obtained were homogeneous with the only exception of the "non neoformans" strains, in which, higher M.I.C. to 5 fluorocytosine values were detected.

Luteocirrhus shearii gen. sp. nov. (Diaporthales, Cryphonectriaceae) pathogenic to Proteaceae in the South Western Australian Floristic Region.

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Crane, Colin; Burgess, Treena I

2013-07-01

Morphological and DNA sequence characteristics of a pathogenic fungus isolated from branch cankers in Proteaceae of the South West Australian Floristic Region elucidated a new genus and species within Cryphonectriaceae (Diaporthales). The pathogen has been isolated from canker lesions in several Banksia species and Lambertia echinata subsp. citrina, and is associated with a serious decline of the rare B. verticillata. Lack of orange pigment in all observed structures except cirrhi, combined with pulvinate to globose black semi-immersed conidiomata with paraphyses, distinguishes the canker fungus from other genera of Cryphonectriaceae. This was confirmed by DNA sequence analysis of the ITS regions, β-tubulin, and LSU genes. The fungus (sexual morph unknown) is described as Luteocirrhus shearii gen. sp. nov. Lesions in seedlings of Banksia spp. following wound inoculation and subsequent recovery confirm Koch's postulates for pathogenicity. This pathogen of native Proteaceae is currently an emerging threat, particularly toward B. baxteri and B. verticillata.

Neurocriptococose por Cryptococcus neoformans não capsulado

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C.S. Lacaz

1993-09-01

Full Text Available Os autores registram um caso de neurocriptococose em paciente HIV-negativo, por Cryptococcus neoformans acapsulado ou deficiente em cápsula. O quadro neurológico era de meningoencefalite subaguda, compatível ao diagnóstico de neurotuberculose, pelo exame do líquido cefalorraqueano (LCR, Estruturas leveduriformes foram encontradas no interior de macrófagos, ao exame citomorfológico do LCR. Cultivo do sedimento do LCR revelou a presença de Cryptococcus neoformans não capsulado (identificação bioquímica. A inoculação da amostra em camundongo, por via intraperitoneal, permitiu a produção de cápsula que desaparecia em cultivos. Foi estudada a micromorfologia do fungo à microscopia eletrônica de varredura. A evolução foi favorável com o emprego da anfotericina B associada a 5-fluorocitosina. Não foi caracterizada a variadade de Criptococcus neoformans agente do processo.

Short Interspersed Nuclear Element (SINE) Sequences in the Genome of the Human Pathogenic Fungus Aspergillus fumigatus Af293.

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Kanhayuwa, Lakkhana; Coutts, Robert H A

2016-01-01

Novel families of short interspersed nuclear element (SINE) sequences in the human pathogenic fungus Aspergillus fumigatus, clinical isolate Af293, were identified and categorised into tRNA-related and 5S rRNA-related SINEs. Eight predicted tRNA-related SINE families originating from different tRNAs, and nominated as AfuSINE2 sequences, contained target site duplications of short direct repeat sequences (4-14 bp) flanking the elements, an extended tRNA-unrelated region and typical features of RNA polymerase III promoter sequences. The elements ranged in size from 140-493 bp and were present in low copy number in the genome and five out of eight were actively transcribed. One putative tRNAArg-derived sequence, AfuSINE2-1a possessed a unique feature of repeated trinucleotide ACT residues at its 3'-terminus. This element was similar in sequence to the I-4_AO element found in A. oryzae and an I-1_AF long nuclear interspersed element-like sequence identified in A. fumigatus Af293. Families of 5S rRNA-related SINE sequences, nominated as AfuSINE3, were also identified and their 5'-5S rRNA-related regions show 50-65% and 60-75% similarity to respectively A. fumigatus 5S rRNAs and SINE3-1_AO found in A. oryzae. A. fumigatus Af293 contains five copies of AfuSINE3 sequences ranging in size from 259-343 bp and two out of five AfuSINE3 sequences were actively transcribed. Investigations on AfuSINE distribution in the fungal genome revealed that the elements are enriched in pericentromeric and subtelomeric regions and inserted within gene-rich regions. We also demonstrated that some, but not all, AfuSINE sequences are targeted by host RNA silencing mechanisms. Finally, we demonstrated that infection of the fungus with mycoviruses had no apparent effects on SINE activity.

The production of monokaryotic hyphae by Cryptococcus neoformans can be induced by high temperature arrest of the cell cycle and is independent of same-sex mating.

Science.gov (United States)

Fu, Jianmin; Morris, Ian R; Wickes, Brian L

2013-01-01

Cryptococcus neoformans is a heterothallic fungal pathogen of humans and animals. Although the fungus grows primarily as a yeast, hyphae are produced during the sexual phase and during a process called monokaryotic fruiting, which is also believed to involve sexual reproduction, but between cells of the same mating type. Here we report a novel monokaryotic fruiting mechanism that is dependent on the cell cycle and occurs in haploid cells in the absence of sexual reproduction. Cells grown at 37°C were found to rapidly produce hyphae (∼4 hrs) and at high frequency (∼40% of the population) after inoculation onto hyphae-inducing agar. Microscopic examination of the 37°C seed culture revealed a mixture of normal-sized and enlarged cells. Micromanipulation of single cells demonstrated that only enlarged cells were able to produce hyphae and genetic analysis confirmed that hyphae did not arise from α-α mating or endoduplication. Cell cycle analysis revealed that cells grown at 37°C had an increased population of cells in G2 arrest, with the proportion correlated with the frequency of monokaryotic fruiting. Cell sorting experiments demonstrated that enlarged cells were only found in the G2-arrested population and only this population contained cells able to produce hyphae. Treatment of cells at low temperature with the G2 cell cycle arrest agent, nocodazole, induced hyphal growth, confirming the role of the cell cycle in this process. Taken together, these results reveal a mating-independent mechanism for monokaryotic fruiting, which is dependent on the cell cycle for induction of hyphal competency.

Investigation on the infection mechanism of the fungus Clonostachys rosea against nematodes using the green fluorescent protein.

Science.gov (United States)

Zhang, Lin; Yang, Jinkui; Niu, Qiuhong; Zhao, Xuna; Ye, Fengping; Liang, Lianming; Zhang, Ke-Qin

2008-04-01

The fungus Clonostachys rosea (syn. Gliocladium roseum) is a potential biocontrol agent. It can suppress the sporulation of the plant pathogenic fungus Botrytis cinerea and kill pathogenic nematodes, but the process of nematode pathogenesis is poorly understood. To help understand the underlying mechanism, we constructed recombinant strains containing a plasmid with both the enhanced green fluorescent protein gene egfp and the hygromycin resistance gene hph. Expression of the green fluorescent protein (GFP) was monitored using fluorescence microscopy. Our observations reveal that the pathogenesis started from the adherence of conidia to nematode cuticle for germination, followed by the penetration of germ tubes into the nematode body and subsequent death and degradation of the nematodes. These are the first findings on the infection process of the fungal pathogen marked with GFP, and the developed method can become an important tool for studying the molecular mechanisms of nematode infection by C. rosea.

Two novel transcriptional regulators are essential for infection-related morphogenesis and pathogenicity of the rice blast fungus Magnaporthe oryzae.

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Xia Yan

2011-12-01

Full Text Available The cyclic AMP-dependent protein kinase A signaling pathway plays a major role in regulating plant infection by the rice blast fungus Magnaporthe oryzae. Here, we report the identification of two novel genes, MoSOM1 and MoCDTF1, which were discovered in an insertional mutagenesis screen for non-pathogenic mutants of M. oryzae. MoSOM1 or MoCDTF1 are both necessary for development of spores and appressoria by M. oryzae and play roles in cell wall differentiation, regulating melanin pigmentation and cell surface hydrophobicity during spore formation. MoSom1 strongly interacts with MoStu1 (Mstu1, an APSES transcription factor protein, and with MoCdtf1, while also interacting more weakly with the catalytic subunit of protein kinase A (CpkA in yeast two hybrid assays. Furthermore, the expression levels of MoSOM1 and MoCDTF1 were significantly reduced in both Δmac1 and ΔcpkA mutants, consistent with regulation by the cAMP/PKA signaling pathway. MoSom1-GFP and MoCdtf1-GFP fusion proteins localized to the nucleus of fungal cells. Site-directed mutagenesis confirmed that nuclear localization signal sequences in MoSom1 and MoCdtf1 are essential for their sub-cellular localization and biological functions. Transcriptional profiling revealed major changes in gene expression associated with loss of MoSOM1 during infection-related development. We conclude that MoSom1 and MoCdtf1 functions downstream of the cAMP/PKA signaling pathway and are novel transcriptional regulators associated with cellular differentiation during plant infection by the rice blast fungus.

The occurrence and pathogenicity of Phoma exigua Desm. var. exigua for selected species of herbs

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Zofia Machowicz-Stefaniak

2012-12-01

Full Text Available P. exigua var. exigua was isolated from underground and aboveground organs of different herb plant species in the years 1998-2006. Pathogenicity tests of three randomly chosen isolates of the fungus T 299, T 261 and T 277 for thyme and of three isolates M 1657, M 1193 and M 1635 for lemon balm were carried out. The effect of water suspension of fungus spores on the germination ability of schizocarps and of infected soil on sprouting and seedling health was studied. The study of microscopic structures of the fungus developing on plants, isolation of the fungus on artificial media and macro- and microscopic analysis on standard media are essential for the correct identification of P. exigua var. exigua. The polyphagous nature of the fungus is confirmed by the obtained results. The tested isolates were found to be occasional pathogens of thyme and lemon balm in the studied conditions. The harmfulness of the tested isolates pointed to inhibition of schizocarp germination, sprouting of plants and the ability to cause necrosis of germs, roots and epicotyl.

Cryptococcus neoformans capsular enlargement and cellular gigantism during Galleria mellonella infection.

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Rocío García-Rodas

Full Text Available We have studied infection of Cryptococcus neoformans in the non-vertebrate host Galleria mellonella with particular interest in the morphological response of the yeast. Inoculation of C. neoformans in caterpillars induced a capsule-independent increase in haemocyte density 2 h after infection. C. neoformans manifested a significant increase in capsule size after inoculation into the caterpillar. The magnitude of capsule increase depended on the temperature, being more pronounced at 37°C than at 30°C, which correlated with an increased virulence of the fungus and reduced phagocytosis at 37°C. Capsule enlargement impaired phagocytosis by haemocytes. Incubation of the yeast in G. mellonella extracts also resulted in capsule enlargement, with the polar lipidic fraction having a prominent role in this effect. During infection, the capsule decreased in permeability. A low proportion of the cells (<5% recovered from caterpillars measured more than 30 µm and were considered giant cells. Giant cells recovered from mice were able to kill the caterpillars in a manner similar to regular cells obtained from in vivo or grown in vitro, establishing their capacity to cause disease. Our results indicate that the morphological transitions exhibited by C. neoformans in mammals also occur in a non-vertebrate host system. The similarities in morphological transitions observed in different animal hosts and in their triggers are consistent with the hypothesis that the cell body and capsular responses represent an adaptation of environmental survival strategies to pathogenesis.

Evaluation of SOC for the presumptive identification of Candida albicans and Cryptococcus neoformans.

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Fleming, W H; Knezek, K L; Dorn, G L

1987-01-01

SOC, a fungal growth medium composed of Solryth, oxgall, and caffeic acid, was evaluated as a medium to provide rapid, differential identification of Candida albicans and Cryptococcus neoformans. Using a variety of common isolation media to produce the yeast inocula, the germ tube methods tested ranked in the following order of decreasing sensitivity: SOC (97% +/- 1), serum (92% +/- 5), rabbit coagulase plasma with EDTA in combination with tryptic soy broth (89% +/- 5), TOC (89% +/- 6), and rabbit coagulase plasma with EDTA (83% +/- 4). In chlamydospore production, SOC also proved to be the most sensitive after 24 h incubation: SOC (96% +/- 2), TOC (80% +/- 2), and cornmeal-Tween 80 agar (14% +/- 3). Other medically important yeasts showed normal patterns of growth within 24 h on SOC, thus assisting in their identification. Eighty strains of Cryptococcus neoformans showed characteristic brown pigmentation on SOC and TOC within 18 h, while all other species of the genus Cryptococcus and 229 Candida isolates did not show a change in pigmentation.

RNA-seq Transcriptome Response of Flax (Linum usitatissimum L.) to the Pathogenic Fungus Fusarium oxysporum f. sp. lini.

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Galindo-González, Leonardo; Deyholos, Michael K

2016-01-01

Fusarium oxysporum f. sp. lini is a hemibiotrophic fungus that causes wilt in flax. Along with rust, fusarium wilt has become an important factor in flax production worldwide. Resistant flax cultivars have been used to manage the disease, but the resistance varies, depending on the interactions between specific cultivars and isolates of the pathogen. This interaction has a strong molecular basis, but no genomic information is available on how the plant responds to attempted infection, to inform breeding programs on potential candidate genes to evaluate or improve resistance across cultivars. In the current study, disease progression in two flax cultivars [Crop Development Center (CDC) Bethune and Lutea], showed earlier disease symptoms and higher susceptibility in the later cultivar. Chitinase gene expression was also divergent and demonstrated and earlier molecular response in Lutea. The most resistant cultivar (CDC Bethune) was used for a full RNA-seq transcriptome study through a time course at 2, 4, 8, and 18 days post-inoculation (DPI). While over 100 genes were significantly differentially expressed at both 4 and 8 DPI, the broadest deployment of plant defense responses was evident at 18 DPI with transcripts of more than 1,000 genes responding to the treatment. These genes evidenced a reception and transduction of pathogen signals, a large transcriptional reprogramming, induction of hormone signaling, activation of pathogenesis-related genes, and changes in secondary metabolism. Among these, several key genes that consistently appear in studies of plant-pathogen interactions, had increased transcript abundance in our study, and constitute suitable candidates for resistance breeding programs. These included: an induced R PMI-induced protein kinase; transcription factors WRKY3, WRKY70, WRKY75, MYB113 , and MYB108 ; the ethylene response factors ERF1 and ERF14 ; two genes involved in auxin/glucosinolate precursor synthesis ( CYP79B2 and CYP79B3 ); the flavonoid

RNA-seq Transcriptome Response of Flax (Linum usitatissimum L. to the Pathogenic Fungus Fusarium oxysporum f. sp. lini.

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Leonardo Miguel Galindo-González

2016-11-01

Full Text Available Fusarium oxysporum f. sp. lini is a hemibiotrophic fungus that causes wilt in flax. Along with rust, fusarium wilt has become an important factor in flax production worldwide. Resistant flax cultivars have been used to manage the disease, but the resistance varies, depending on the interactions between specific cultivars and isolates of the pathogen. This interaction has a strong molecular basis, but no genomic information is available on how the plant responds to attempted infection, to inform breeding programs on potential candidate genes to evaluate or improve resistance across cultivars. In the current study, disease progression in two flax cultivars (CDC Bethune and Lutea, showed earlier disease symptoms and higher susceptibility in the later cultivar. Chitinase gene expression was also divergent and demonstrated and earlier molecular response in Lutea. The most resistant cultivar (CDC Bethune was used for a full RNA-seq transcriptome study through a time-course at 2, 4, 8 and 18 days post-inoculation (DPI. While over 100 genes were significantly differentially expressed at both 4 and 8 DPI, the broadest deployment of plant defense responses was evident at 18 DPI with transcripts of more than 1,000 genes responding to the treatment. These genes evidenced a reception and transduction of pathogen signals, a large transcriptional reprogramming, induction of hormone signalling, activation of pathogenesis-related (PR genes, and changes in secondary metabolism. Among these several key genes, that consistently appear in studies of plant-pathogen interactions, had increased transcript abundance in our study, and constitute suitable candidates for resistance breeding programs. These included: an induced RPMI-induced protein kinase (RIPK; transcription factors WRKY3, WRKY70, WRKY75, MYB113 and MYB108; the ethylene response factors ERF1 and ERF14; two genes involved in auxin/glucosinolate precursor synthesis (CYP79B2 and CYP79B3; the flavonoid

Rapid Identification of Pathogenic Fungi Directly from Cultures by Using Multiplex PCR

OpenAIRE

Luo, Guizhen; Mitchell, Thomas G.

2002-01-01

A multiplex PCR method was developed to identify simultaneously multiple fungal pathogens in a single reaction. Five sets of species-specific primers were designed from the internal transcribed spacer (ITS) regions, ITS1 and ITS2, of the rRNA gene to identify Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, and Aspergillus fumigatus. Another set of previously published ITS primers, CN4 and CN5, were used to identify Cryptococcus neoformans. Three sets of primers w...

Potential for spread of the white-nose fungus (Pseudogymnoascus destructans in the Americas: use of Maxent and NicheA to assure strict model transference

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Luis E. Escobar

2014-11-01

Full Text Available Emerging infectious diseases can present serious threats to wildlife, even to the point of causing extinction. White- nose fungus (Pseudogymnoascus destructans is causing an epizootic in bats that is expanding rapidly, both geographically and taxonomically. Little is known of the ecology and distributional potential of this intercontinental pathogen. We address this gap via ecological niche models that characterise coarse resolution niche differences between fungus populations on dif- ferent continents, identifying areas potentially vulnerable to infection in South America. Here we explore a novel approach to identifying areas of potential distribution across novel geographic regions that avoids perilious extrapolation into novel environments. European and North American fungus populations show differential use of environmental space, but rather than niche differentiation, we find that changes are best attributed to climatic differences between the two continents. Suitable areas for spread of the pathogen were identified across southern South America; however caution should be taken to avoid underestimating the potential for spread of this pathogen in South America.

Potential for spread of the white-nose fungus (Pseudogymnoascus destructans) in the Americas: use of Maxent and NicheA to assure strict model transference.

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Escobar, Luis E; Lira-Noriega, Andrés; Medina-Vogel, Gonzalo; Townsend Peterson, A

2014-11-01

Emerging infectious diseases can present serious threats to wildlife, even to the point of causing extinction. Whitenose fungus (Pseudogymnoascus destructans) is causing an epizootic in bats that is expanding rapidly, both geographically and taxonomically. Little is known of the ecology and distributional potential of this intercontinental pathogen. We address this gap via ecological niche models that characterise coarse resolution niche differences between fungus populations on different continents, identifying areas potentially vulnerable to infection in South America. Here we explore a novel approach to identifying areas of potential distribution across novel geographic regions that avoids perilious extrapolation into novel environments. European and North American fungus populations show differential use of environmental space, but rather than niche differentiation, we find that changes are best attributed to climatic differences between the two continents. Suitable areas for spread of the pathogen were identified across southern South America; however caution should be taken to avoid underestimating the potential for spread of this pathogen in South America.

Pathogen Causing Disease of Diagnosis PCR Tecnology

OpenAIRE

SEVİNDİK, Emre; KIR, A. Çağrı; BAŞKEMER, Kadir; UZUN, Veysel

2013-01-01

Polimerase chain reaction (PCR) with which, the development of recombinant DNA tecnology, a technique commonly used in field of moleculer biology and genetic. Duplication of the target DNA is provided with this technique without the need for cloning. Some fungus species, bacteria, viruses constitutent an important group of pathogenicity in human, animals and plants. There are routinely applied types of PCR in the detection of pathogens infections diseases. These Nested- PCR, Real- Time PCR, M...

Genome wide analysis of the transition to pathogenic lifestyles in Magnaporthales fungi

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The rice blast fungus Pyricularia oryzae (syn. Magnaporthe oryzae, Magnaporthe grisea), a member of the order Magnaporthales in the class Sordariomycetes, is an important plant pathogen and a model species for studying pathogen infection and plant-fungal interaction. In this study, we generated geno...

Fungus mediated biosynthesis of WO3 nanoparticles using Fusarium solani extract

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Kavitha, N. S.; Venkatesh, K. S.; Palani, N. S.; Ilangovan, R.

2017-05-01

Currently nanoparticles were synthesized by emphasis bioremediation process due to less hazardous, eco-friendly and imperative applications on biogenic process. Fungus mediated biosynthesis strategy has been developed to prepare tungsten oxide nanoflakes (WO3, NFs) using the plant pathogenic fungus F.solani. The powder XRD pattern revealed the monoclinic crystal structure with improved crystalline nature of the synthesized WO3 nanoparticles. FESEM images showed the flake-like morphology of WO3, with average thickness and length around 40 nm and 300 nm respectively. The Raman spectrum of WO3 NFs showed their characteristic vibration modes that revealed the defect free nature of the WO3 NFs. Further, the elemental analysis indicated the stoichiometric composition of WO3 phase.

Draft Genome Sequence of the Human-Pathogenic Fungus Scedosporium boydii

OpenAIRE

Duvaux, Ludovic; Shiller, Jason; Vandeputte, Patrick; Dug? de Bernonville, Thomas; Thornton, Christopher; Papon, Nicolas; Le Cam, Bruno; Bouchara, Jean-Philippe; Gastebois, Amandine

2017-01-01

ABSTRACT The opportunistic fungal pathogen Scedosporium boydii is the most common Scedosporium species in French patients with cystic fibrosis. Here we present the first genome report for S.?boydii, providing a resource which may enable the elucidation of the pathogenic mechanisms in this species.

Pathogenicity of the bioherbicide fungus chondrostereum purpureum to some trees and shrubs of southern Vancouver Island. FRDA report No. 246

Energy Technology Data Exchange (ETDEWEB)

Wall, R.E.

1996-11-01

Chondrostereum purpureum is a common stem-invading fungus of trees and shrubs. The fungus has attracted interest as a bioherbicide, but a better understanding of its biology is required. This study was undertaken to determine the range of virulence of isolates of C. purpureum from a given region on major hardwood species in British Columbia. The investigators inoculated wounds of stems of standing red alder (Alnus rubra) and bigleaf maple (Acer macrophyllum) saplings with 11 isolates of the fungus and measured the resulting stem cankers as an index of virulence. They also inoculated eight hardwood and shrub species with two isolates to demonstrate the range of susceptibility of species to the fungus, as well as the intraspecific variation.

Surface-associated plasminogen binding of Cryptococcus neoformans promotes extracellular matrix invasion.

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Jamal Stie

2009-06-01

Full Text Available The fungal pathogen Cryptococcus neoformans is a leading cause of illness and death in persons with predisposing factors, including: malignancies, solid organ transplants, and corticosteroid use. C. neoformans is ubiquitous in the environment and enters into the lungs via inhalation, where it can disseminate through the bloodstream and penetrate the central nervous system (CNS, resulting in a difficult to treat and often-fatal infection of the brain, called meningoencephalitis. Plasminogen is a highly abundant protein found in the plasma component of blood and is necessary for the degradation of fibrin, collagen, and other structural components of tissues. This fibrinolytic system is utilized by cancer cells during metastasis and several pathogenic species of bacteria have been found to manipulate the host plasminogen system to facilitate invasion of tissues during infection by modifying the activation of this process through the binding of plasminogen at their surface.The invasion of the brain and the central nervous system by penetration of the protective blood-brain barrier is a prerequisite to the establishment of meningoencephalitis by the opportunistic fungal pathogen C. neoformans. In this study, we examined the ability of C. neoformans to subvert the host plasminogen system to facilitate tissue barrier invasion. Through a combination of biochemical, cell biology, and proteomic approaches, we have shown that C. neoformans utilizes the host plasminogen system to cross tissue barriers, providing support for the hypothesis that plasminogen-binding may contribute to the invasion of the blood-brain barrier by penetration of the brain endothelial cells and underlying matrix. In addition, we have identified the cell wall-associated proteins that serve as plasminogen receptors and characterized both the plasminogen-binding and plasmin-activation potential for this significant human pathogen.The results of this study provide evidence for the

Climate forcing of an emerging pathogenic fungus across a montane multi-host community.

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Clare, Frances C; Halder, Julia B; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S; Cunningham, Andrew A; Rowcliffe, Marcus; Garner, Trenton W J; Bosch, Jaime; Fisher, Matthew C

2016-12-05

Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Authors.

Ecology of Fungus Gnats (Bradysia spp.) in Greenhouse Production Systems Associated with Disease-Interactions and Alternative Management Strategies.

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Cloyd, Raymond A

2015-04-09

Fungus gnats (Bradysia spp.) are major insect pests of greenhouse-grown horticultural crops mainly due to the direct feeding damage caused by the larvae, and the ability of larvae to transmit certain soil-borne plant pathogens. Currently, insecticides and biological control agents are being used successively to deal with fungus gnat populations in greenhouse production systems. However, these strategies may only be effective as long as greenhouse producers also implement alternative management strategies such as cultural, physical, and sanitation. This includes elimination of algae, and plant and growing medium debris; placing physical barriers onto the growing medium surface; and using materials that repel fungus gnat adults. This article describes the disease-interactions associated with fungus gnats and foliar and soil-borne diseases, and the alternative management strategies that should be considered by greenhouse producers in order to alleviate problems with fungus gnats in greenhouse production systems.

Ecology of Fungus Gnats (Bradysia spp. in Greenhouse Production Systems Associated with Disease-Interactions and Alternative Management Strategies

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Raymond A. Cloyd

2015-04-01

Full Text Available Fungus gnats (Bradysia spp. are major insect pests of greenhouse-grown horticultural crops mainly due to the direct feeding damage caused by the larvae, and the ability of larvae to transmit certain soil-borne plant pathogens. Currently, insecticides and biological control agents are being used successively to deal with fungus gnat populations in greenhouse production systems. However, these strategies may only be effective as long as greenhouse producers also implement alternative management strategies such as cultural, physical, and sanitation. This includes elimination of algae, and plant and growing medium debris; placing physical barriers onto the growing medium surface; and using materials that repel fungus gnat adults. This article describes the disease-interactions associated with fungus gnats and foliar and soil-borne diseases, and the alternative management strategies that should be considered by greenhouse producers in order to alleviate problems with fungus gnats in greenhouse production systems.

Carbon dioxide is a powerful inducer of monokaryotic hyphae and spore development in Cryptococcus gattii and carbonic anhydrase activity is dispensable in this dimorphic transition.

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Ren, Ping; Chaturvedi, Vishnu; Chaturvedi, Sudha

2014-01-01

Cryptococcus gattii is unique among human pathogenic fungi with specialized ecological niche on trees. Since leaves concentrate CO2, we investigated the role of this gaseous molecule in C. gattii biology and virulence. We focused on the genetic analyses of β-carbonic anhydrase (β-CA) encoded by C. gattii CAN1 and CAN2 as later is critical for CO2 sensing in a closely related pathogen C. neoformans. High CO2 conditions induced robust development of monokaryotic hyphae and spores in C. gattii. Conversely, high CO2 completely repressed hyphae development in sexual mating. Both CAN1 and CAN2 were dispensable for CO2 induced morphogenetic transitions. However, C. gattii CAN2 was essential for growth in ambient air similar to its reported role in C. neoformans. Both can1 and can2 mutants retained full pathogenic potential in vitro and in vivo. These results provide insight into C. gattii adaptation for arboreal growth and production of infectious propagules by β-CA independent mechanism(s).

Antibacterial polyketides from the jellyfish-derived fungus Paecilomyces variotii.

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Liu, Juan; Li, Famei; Kim, Eun La; Li, Jian Lin; Hong, Jongki; Bae, Kyung Sook; Chung, Hae Young; Kim, Hyung Sik; Jung, Jee H

2011-08-26

Four new polyketides (1-4) were isolated from the fungus Paecilomyces variotii, which was derived from the jellyfish Nemopilema nomurai. The planar structures and relative configurations of these polyketides were elucidated on the basis of spectroscopic analyses, including 2D NMR experiments. The compounds showed inhibitory activity against pathogenic bacteria including methicillin-resistant Staphylococcus aureus 3089 and multi-drug-resistant Vibrio parahemolyticus 7001 with MIC values in the range 5-40 μg/mL.

Sclerotinia sclerotiorum (Lib.) de Bary: biology and molecular traits of a cosmopolitan pathogen

NARCIS (Netherlands)

Bolton, M.D.; Thomma, B.P.H.J.; Nelson, B.D.

2006-01-01

Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen causing disease in a wide range of plants. This review summarizes current knowledge of mechanisms employed by the fungus to parasitize its host with emphasis on biology, physiology and molecular aspects of pathogenicity. In

Microbial lipid production by oleaginous yeast Cryptococcus sp. in the batch cultures using corncob hydrolysate as carbon source

International Nuclear Information System (INIS)

Chang, Yi-Huang; Chang, Ku-Shang; Lee, Ching-Fu; Hsu, Chuan-Liang; Huang, Cheng-Wei; Jang, Hung-Der

2015-01-01

To realize the feasibility of biodiesel production from high-lipid cell culture, microbial lipid production by the oleaginous yeasts was studied using glucose and sucrose as carbon source. Among the tested strains, Cryptococcus sp. SM5S05 accumulated the highest levels of intracellular lipids. The crude lipid contents of Cryptococcus sp. cultured in yeast malt agar reached 30% on a dry weight basis. The accumulation of lipids strongly depended on carbon/nitrogen ratio and nitrogen concentration. The highest content of lipids, measured at a carbon/nitrogen ratio of 60–90 and at a nitrogen concentration of 0.2%, was 60–57% lipids in the dry biomass. Batch cultures using corncob hydrolysate demonstrated that there was minimal inhibitory effect with a reducing sugar concentration of 60 g l −1 or higher. Batch cultures of Cryptococcus sp. SM5S05 in the corncob hydrolysate medium with 60 g l −1 glucose resulted in a dry biomass, lipid yields, and content of 12.6 g l −1 , 7.6 g l −1 , and 60.2%, respectively. The lipids contained mainly long-chain saturated and unsaturated fatty acids with 16 and 18 carbon atoms. The fatty acid profile of Cryptococcus oils was quite similar to that of conventional vegetable oil. The cost of lipid production could be further reduced with corncob hydrolysate being utilized as the raw material for the oleaginous yeast. The results showed that the microbial lipid from Cryptococcus sp. was a potential alternative resource for biodiesel production. - Highlights: • Microbial oil production from oleaginous yeast Cryptococcus sp. was studied. • Accumulation of lipid strongly depended on C/N ratio and nitrogen concentration. • Cultures in hydrolysate medium with 60 g/l glucose resulted in maximum lipid yields. • Maximal lipid content in the Cryptococcus sp. were 60.2% on dried weight basis

Repurposing of Aspirin and Ibuprofen as Candidate Anti-Cryptococcus Drugs

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Ogundeji, Adepemi O.; Pohl, Carolina H.

2016-01-01

The usage of fluconazole and amphotericin B in clinical settings is often limited by, among other things, drug resistance development and undesired side effects. Thus, there is a constant need to find new drugs to better manage fungal infections. Toward this end, the study described in this paper considered the repurposing of aspirin (acetylsalicylic acid) and ibuprofen as alternative drugs to control the growth of cryptococcal cells. In vitro susceptibility tests, including a checkerboard assay, were performed to assess the response of Cryptococcus neoformans and Cryptococcus gattii to the above-mentioned anti-inflammatory drugs. Next, the capacity of these two drugs to induce stress as well as their mode of action in the killing of cryptococcal cells was determined. The studied fungal strains revealed a response to both aspirin and ibuprofen that was dose dependent, with ibuprofen exerting greater antimicrobial action. More importantly, the MICs of these drugs did not negatively (i) affect growth or (ii) impair the functioning of macrophages; rather, they enhanced the ability of these immune cells to phagocytose cryptococcal cells. Ibuprofen was also shown to act in synergy with fluconazole and amphotericin B. The treatment of cryptococcal cells with aspirin or ibuprofen led to stress induction via activation of the high-osmolarity glycerol (HOG) pathway, and cell death was eventually achieved through reactive oxygen species (ROS)-mediated membrane damage. The presented data highlight the potential clinical application of aspirin and ibuprofen as candidate anti-Cryptococcus drugs. PMID:27246782

Cryptococcus neoformans en el contenido gástrico de un paciente con SIDA Cryptococcus neoformans in the gastric contents of an AIDS patient

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S. Garro

2006-12-01

Full Text Available Se comunica la observación microscópica y el aislamiento de Cryptococcus neoformans de contenido gástrico de un paciente con SIDA, obtenido por aspiración con sonda nasogástrica y enviado para su estudio parasitológico. En el examen en fresco del concentrado del material, llamaron la atención escasas levaduras redondas. El agregado de tinta china reveló la cápsula característica de C. neoformans. El cultivo de la muestra en agar extracto de semillas de girasol incubado a 37 °C durante 7 días permitió el aislamiento de colonias pardas de C. neoformans. Los hemocultivos para hongos fueron negativos y ante la imposibilidad de obtener LCR, por negativa del paciente, se determinó el antígeno polisacarídico capsular de C. neoformans en sangre, que fue positivo hasta la dilución 1:100. Luego del hallazgo de C. neoformans en el contenido gástrico y del resultado positivo de la antigenemia, el paciente -sospechado inicialmente como portador de diarrea por Cryptosporidium sp.-, fue medicado con fluconazol por vía oral, a razón de 800 mg/día, tras negarse a recibir medicación endovenosa. La presente comunicación da cuenta del hallazgo de C. neoformans en un material clínico donde su presencia es infrecuente y destaca su valor en el diagnóstico de la criptococosis.The microscopic observation and isolation of Cryptococcus neoformans from the gastric contents of an AIDS patient, obtained by aspiration with a nasogastric catheter and parasitologically studied, is communicated. Because of the limited number of round yeasts visualized by wet mount of the sample concentrate, India ink was added: the typical capsules of C. neoformans were then observed. Dark brown colonies of C. neoformans were isolated from the clinical sample cultured on sunflower-seed-extract agar, incubated at 37 °C for 7 days. Bloodcultures for fungi were negative; it was impossible to obtain CSF due to the patient&'s refusal, then the capsular polysaccharide antigen

Cytotoxic and Antifungal Activities of 5-Hydroxyramulosin, a Compound Produced by an Endophytic Fungus Isolated from Cinnamomum mollisimum

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Carolina Santiago

2012-01-01

Full Text Available An endophytic fungus isolated from the plant Cinnamomum mollissimum was investigated for the bioactivity of its metabolites. The fungus, similar to a Phoma sp., was cultured in potato dextrose broth for two weeks, followed by extraction with ethyl acetate. The crude extract obtained was fractionated by high-performance liquid chromatography. Both crude extract and fractions were assayed for cytotoxicity against P388 murine leukemic cells and inhibition of bacterial and fungal pathogens. The bioactive extract fraction was purified further and characterized by nuclear magnetic resonance, mass spectral and X-ray crystallography analysis. A polyketide compound, 5-hydroxyramulosin, was identified as the constituent of the bioactive fungal extract fraction. This compound inhibited the fungal pathogen Aspergillus niger (IC50 1.56 μg/mL and was cytotoxic against murine leukemia cells (IC50 2.10 μg/mL. 5-Hydroxyramulosin was the major compound produced by the endophytic fungus. This research suggests that fungal endophytes are a good source of bioactive metabolites which have potential applications in medicine.

The alkalophilic fungus Sodiomyces alkalinus hosts beta- and gammapartitiviruses together with a new fusarivirus

Czech Academy of Sciences Publication Activity Database

Hrabáková, Lenka; Grum-Grzhimaylo, A. A.; Koloniuk, Igor; Debets, A.J. M.; Sarkisova, Tatiana; Petrzik, Karel

2017-01-01

Roč. 12, č. 11 (2017), č. článku e0187799. E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : double-stranded-rna * plant-pathogenic fungus * molecular characterization * confers hypovirulence Subject RIV: EE - Microbiology, Virology OBOR OECD: Virology Impact factor: 2.806, year: 2016

The link between rapid enigmatic amphibian decline and the globally emerging chytrid fungus.

Science.gov (United States)

Lötters, Stefan; Kielgast, Jos; Bielby, Jon; Schmidtlein, Sebastian; Bosch, Jaime; Veith, Michael; Walker, Susan F; Fisher, Matthew C; Rödder, Dennis

2009-09-01

Amphibians are globally declining and approximately one-third of all species are threatened with extinction. Some of the most severe declines have occurred suddenly and for unknown reasons in apparently pristine habitats. It has been hypothesized that these "rapid enigmatic declines" are the result of a panzootic of the disease chytridiomycosis caused by globally emerging amphibian chytrid fungus. In a Species Distribution Model, we identified the potential distribution of this pathogen. Areas and species from which rapid enigmatic decline are known significantly overlap with those of highest environmental suitability to the chytrid fungus. We confirm the plausibility of a link between rapid enigmatic decline in worldwide amphibian species and epizootic chytridiomycosis.

Short Rotations in Forest Plantations Accelerate Virulence Evolution in Root-Rot Pathogenic Fungi

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Jean-Paul Soularue

2017-06-01

Full Text Available As disease outbreaks in forest plantations are causing concern worldwide, a clear understanding of the influence of silvicultural practices on the development of epidemics is still lacking. Importantly, silvicultural practices are likely to simultaneously affect epidemiological and evolutionary dynamics of pathogen populations. We propose a genetically explicit and individual-based model of virulence evolution in a root-rot pathogenic fungus spreading across forest landscapes, taking the Armillaria ostoyae–Pinus pinaster pathosystem as reference. We used the model to study the effects of rotation length on the evolution of virulence and the propagation of the fungus within a forest landscape composed of even-aged stands regularly altered by clear-cutting and thinning operations. The life cycle of the fungus modeled combines asexual and sexual reproduction modes, and also includes parasitic and saprotrophic phases. Moreover, the tree susceptibility to the pathogen is primarily determined by the age of the stand. Our simulations indicated that the shortest rotation length accelerated both the evolution of virulence and the development of the epidemics, whatever the genetic variability in the initial fungal population and the asexuality rate of the fungal species

[Presumptive identification of Cryptococcus gattii isolated from Terminalia catappa in Montería city, Córdoba, Colombia].

Science.gov (United States)

Contreras Martínez, Orfa Inés; Aycardi Morinelli, María Paulina; Alarcón Furnieles, Jany Luz; Jaraba Ramos, Aparicio Manuel

2011-01-01

the members of the Cryptococcus neoformans species complex are responsible for cryptococcosis in animals and humans. Human infection is thought to be acquired by inhalation of airborne propagules from an environmental source; therefore it is greatly important to study their habitat. to determine the ecological relationship of Cryptococcus gattii with Terminalia catappa trees present in urban areas of Montería city in Colombia. a total of 163 Terminalia catappa trees were selected; some samples were taken from the bark, the leaves, the flowers, the fruits of these trees and from the surrounding soil. The yeast was isolated using the Guizotia abyssinica seed agar medium; it was identified thanks to biochemical and morphologic tests whereas the right variety was determined by L-canavanine-glycine-bromothymol blue (CGB), D-proline and D-tryptophan tests. there was obtained 9.050 CFU/g isolate of Cryptococcus spp., 5.795 CFU/g of which were presumptively identified as Cryptococcus gattii. The highest percentage of isolates was found in flowers, followed by bark and fruits, presenting small cellular and capsular sizes. These isolates were more frequent in the south of the city, followed by the center zone and the lowest percentage in the northern zone. these findings confirmed the close relationship of Cryptococcus gattii and Terminalia catappa, being this the first study conducted in Monteria city. These results give us meaningful information for understanding and analyzing the epidemiology of cryptococcosis in Monteria city, Colombia.

Cryptococcus haglerorum, sp. nov., an anamorphic basidiomycetous yeast isolated from nests of the leaf-cutting ant Atta sexdens.

NARCIS (Netherlands)

Middelhoven, W.J.; Fonseca, A.; Carreiro, S.C.; Pagnocca, F.C.; Bueno, O.C.

2003-01-01

A yeast strain (CBS 8902) was isolated from the nest of a leaf-cutting ant and was shown to be related to Cryptococcus humicola. Sequencing of the D1/D2 region of the 26S ribosomal DNA and physiological characterization revealed a separate taxonomic position. A novel species named Cryptococcus

C. elegans germline-deficient mutants respond to pathogen infection using shared and distinct mechanisms.

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Michael TeKippe

2010-07-01

Full Text Available Reproduction extracts a cost in resources that organisms are then unable to utilize to deal with a multitude of environmental stressors. In the nematode C. elegans, development of the germline shortens the lifespan of the animal and increases its susceptibility to microbial pathogens. Prior studies have demonstrated germline-deficient nematodes to have increased resistance to gram negative bacteria. We show that germline-deficient strains display increased resistance across a broad range of pathogens including gram positive and gram negative bacteria, and the fungal pathogen Cryptococcus neoformans. Furthermore, we show that the FOXO transcription factor DAF-16, which regulates longevity and immunity in C. elegans, appears to be crucial for maintaining longevity in both wild-type and germline-deficient backgrounds. Our studies indicate that germline-deficient mutants glp-1 and glp-4 respond to pathogen infection using common and different mechanisms that involve the activation of DAF-16.

The Blast Fungus Decoded: Genomes in Flux

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Thorsten Langner

2018-04-01

Full Text Available Plant disease outbreaks caused by fungi are a chronic threat to global food security. A prime case is blast disease, which is caused by the ascomycete fungus Magnaporthe oryzae (syn. Pyricularia oryzae, which is infamous as the most destructive disease of the staple crop rice. However, despite its Linnaean binomial name, M. oryzae is a multihost pathogen that infects more than 50 species of grasses. A timely study by P. Gladieux and colleagues (mBio 9:e01219-17, 2018, https://doi.org/10.1128/mBio.01219-17 reports the most extensive population genomic analysis of the blast fungus thus far. M. oryzae consists of an assemblage of differentiated lineages that tend to be associated with particular host genera. Nonetheless, there is clear evidence of gene flow between lineages consistent with maintaining M. oryzae as a single species. Here, we discuss these findings with an emphasis on the ecologic and genetic mechanisms underpinning gene flow. This work also bears practical implications for diagnostics, surveillance, and management of blast diseases.

The Blast Fungus Decoded: Genomes in Flux.

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Langner, Thorsten; Białas, Aleksandra; Kamoun, Sophien

2018-04-17

Plant disease outbreaks caused by fungi are a chronic threat to global food security. A prime case is blast disease, which is caused by the ascomycete fungus Magnaporthe oryzae (syn. Pyricularia oryzae ), which is infamous as the most destructive disease of the staple crop rice. However, despite its Linnaean binomial name, M. oryzae is a multihost pathogen that infects more than 50 species of grasses. A timely study by P. Gladieux and colleagues (mBio 9:e01219-17, 2018, https://doi.org/10.1128/mBio.01219-17) reports the most extensive population genomic analysis of the blast fungus thus far. M. oryzae consists of an assemblage of differentiated lineages that tend to be associated with particular host genera. Nonetheless, there is clear evidence of gene flow between lineages consistent with maintaining M. oryzae as a single species. Here, we discuss these findings with an emphasis on the ecologic and genetic mechanisms underpinning gene flow. This work also bears practical implications for diagnostics, surveillance, and management of blast diseases. Copyright © 2018 Langner et al.

Antifungal Activity of Decyl Gallate against Several Species of Pathogenic Fungi

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Ana Carolina Alves de Paula e Silva

2014-01-01

Full Text Available This work aims to demonstrate that the gallic acid structure modification to the decyl gallate (G14 compound contributed to increase the antifungal activity against several species of pathogenic fungi, mainly, Candida spp., Cryptococcus spp., Paracoccidioides spp., and Histoplasma capsulatum, according to standardized microdilution method described by Clinical Laboratory Standard Institute (CLSI documents. Moreover this compound has a particularly good selectivity index value, which makes it an excellent candidate for broad-spectrum antifungal prototype and encourages the continuation of subsequent studies for the discovery of its mechanism of action.

Identification of genes from the fungal pathogen Cryptococcus neoformans related to transmigration into the central nervous system.

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Hsiang-Kuang Tseng

Full Text Available A mouse brain transmigration assessment (MBTA was created to investigate the central nervous system (CNS pathogenesis of cryptococcal meningoencephalitis.Two cryptococcal mutants were identified from a pool of 109 pre-selected mutants that were signature-tagged with the nourseothricin acetyltransferase (NAT resistance cassette. These two mutants displayed abnormal transmigration into the central nervous system. One mutant displaying decreased transmigration contains a null mutation in the putative FNX1 gene, whereas the other mutant possessing a null mutation in the putative RUB1 gene exhibited increased transmigration into the brain. Two macrophage adhesion-defective mutants in the pool, 12F1 and 3C9, showed reduced phagocytosis by macrophages, but displayed no defects in CNS entry suggesting that transit within macrophages (the "Trojan horse" model of CNS entry is not the primary mechanism for C. neoformans migration into the CNS in this MBTA.This research design provides a new strategy for genetic impact studies on how Cryptococcus passes through the blood-brain barrier (BBB, and the specific isolated mutants in this assay support a transcellular mechanism of CNS entry.

Low diversity Cryptococcus neoformans variety grubii multilocus sequence types from Thailand are consistent with an ancestral African origin.

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Sitali P Simwami

2011-04-01

Full Text Available The global burden of HIV-associated cryptococcal meningitis is estimated at nearly one million cases per year, causing up to a third of all AIDS-related deaths. Molecular epidemiology constitutes the main methodology for understanding the factors underpinning the emergence of this understudied, yet increasingly important, group of pathogenic fungi. Cryptococcus species are notable in the degree that virulence differs amongst lineages, and highly-virulent emerging lineages are changing patterns of human disease both temporally and spatially. Cryptococcus neoformans variety grubii (Cng, serotype A constitutes the most ubiquitous cause of cryptococcal meningitis worldwide, however patterns of molecular diversity are understudied across some regions experiencing significant burdens of disease. We compared 183 clinical and environmental isolates of Cng from one such region, Thailand, Southeast Asia, against a global MLST database of 77 Cng isolates. Population genetic analyses showed that Thailand isolates from 11 provinces were highly homogenous, consisting of the same genetic background (globally known as VNI and exhibiting only ten nearly identical sequence types (STs, with three (STs 44, 45 and 46 dominating our sample. This population contains significantly less diversity when compared against the global population of Cng, specifically Africa. Genetic diversity in Cng was significantly subdivided at the continental level with nearly half (47% of the global STs unique to a genetically diverse and recombining population in Botswana. These patterns of diversity, when combined with evidence from haplotypic networks and coalescent analyses of global populations, are highly suggestive of an expansion of the Cng VNI clade out of Africa, leading to a limited number of genotypes founding the Asian populations. Divergence time testing estimates the time to the most common ancestor between the African and Asian populations to be 6,920 years ago (95% HPD

Short Interspersed Nuclear Element (SINE Sequences in the Genome of the Human Pathogenic Fungus Aspergillus fumigatus Af293.

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Lakkhana Kanhayuwa

Full Text Available Novel families of short interspersed nuclear element (SINE sequences in the human pathogenic fungus Aspergillus fumigatus, clinical isolate Af293, were identified and categorised into tRNA-related and 5S rRNA-related SINEs. Eight predicted tRNA-related SINE families originating from different tRNAs, and nominated as AfuSINE2 sequences, contained target site duplications of short direct repeat sequences (4-14 bp flanking the elements, an extended tRNA-unrelated region and typical features of RNA polymerase III promoter sequences. The elements ranged in size from 140-493 bp and were present in low copy number in the genome and five out of eight were actively transcribed. One putative tRNAArg-derived sequence, AfuSINE2-1a possessed a unique feature of repeated trinucleotide ACT residues at its 3'-terminus. This element was similar in sequence to the I-4_AO element found in A. oryzae and an I-1_AF long nuclear interspersed element-like sequence identified in A. fumigatus Af293. Families of 5S rRNA-related SINE sequences, nominated as AfuSINE3, were also identified and their 5'-5S rRNA-related regions show 50-65% and 60-75% similarity to respectively A. fumigatus 5S rRNAs and SINE3-1_AO found in A. oryzae. A. fumigatus Af293 contains five copies of AfuSINE3 sequences ranging in size from 259-343 bp and two out of five AfuSINE3 sequences were actively transcribed. Investigations on AfuSINE distribution in the fungal genome revealed that the elements are enriched in pericentromeric and subtelomeric regions and inserted within gene-rich regions. We also demonstrated that some, but not all, AfuSINE sequences are targeted by host RNA silencing mechanisms. Finally, we demonstrated that infection of the fungus with mycoviruses had no apparent effects on SINE activity.

Cytotoxic and antibacterial substances against multi-drug resistant pathogens from marine sponge symbiont: Citrinin, a secondary metabolite of Penicillium sp.

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Subramani, Ramesh; Kumar, Rohitesh; Prasad, Pritesh; Aalbersberg, William; Retheesh, S T

2013-04-01

To Isolate, purify, characterize, and evaluate the bioactive compounds from the sponge-derived fungus Penicillium sp. FF001 and to elucidate its structure. The fungal strain FF001 with an interesting bioactivity profile was isolated from a marine Fijian sponge Melophlus sp. Based on conidiophores aggregation, conidia development and mycelia morphological characteristics, the isolate FF001 was classically identified as a Penicillium sp. The bioactive compound was identified using various spectral analysis of UV, high resolution electrospray ionization mass spectra, 1H and 13C NMR spectral data. Further minimum inhibitory concentrations (MICs) assay and brine shrimp cytotoxicity assay were also carried out to evaluate the biological properties of the purified compound. Bioassay guided fractionation of the EtOAc extract of a static culture of this Penicillium sp. by different chromatographic methods led the isolation of an antibacterial, anticryptococcal and cytotoxic active compound, which was identified as citrinin (1). Further, citrinin (1) is reported for its potent antibacterial activity against methicillin-resistant Staphylococcus aureus (S. aureus), rifampicin-resistant S. aureus, wild type S. aureus and vancomycin-resistant Enterococcus faecium showed MICs of 3.90, 0.97, 1.95 and 7.81 µg/mL, respectively. Further citrinin (1) displayed significant activity against the pathogenic yeast Cryptococcus neoformans (MIC 3.90 µg/mL), and exhibited cytotoxicity against brine shrimp larvae LD50 of 96 µg/mL. Citrinin (1) is reported from sponge associated Penicillium sp. from this study and for its strong antibacterial activity against multi-drug resistant human pathogens including cytotoxicity against brine shrimp larvae, which indicated that sponge associated Penicillium spp. are promising sources of natural bioactive metabolites.

Targeting the Cryptococcus neoformans var. grubii Cell Wall Using Lectins: Study of the Carbohydrate-Binding Domain

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Pamella de Brito Ximenes

2015-02-01

Full Text Available Cryptococcus neoformans var. grubii is considered to be the major cause of cryptococcosis in immunosuppressed patients. Understanding cell wall glycoproteins using lectins is of medical interest and can contribute to specific therapy. The aim of this study was to evaluate the carbohydrates on the cell wall of Cryptococcus neoformans var. grubii clinical isolates, using a fluorescein isothiocyanate-lectin binding protocol. Thirty yeast strains stocked in the culture collection were cultivated for 2 days at 30 °C with shaking. Cells were obtained by centrifugation, washed in phosphate-buffered saline, and a suspension of 107 cells/mL was obtained. To determine the binding profile of lectins, concanavalin A (Con A, wheat germ agglutinin (WGA, Ulex europaeus agglutinin I (UEA-I, and peanut agglutinin (PNA conjugated to fluorescein were used. All the tested clinical isolates of Cryptococcus neoformans var. grubii were intensely stained by WGA, moderately stained by Con A, and weakly stained by PNA and UEA-I. Thus, Cryptococcus can be detected in clinical specimens such as blood and cerebrospinal fluid using the fluorescent lectin WGA, which may be considered as an option for detection in cases of suspected cryptococcosis with low laboratory sensitivity. Future applications may be developed using this basic tool.

Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America.

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Tara Chestnut

Full Text Available Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd, is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L(-1. The highest density observed was ∼3 million zoospores L(-1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure to free

A glycosylphosphatidylinositol anchor is required for membrane localization but dispensable for cell wall association of chitin deacetylase 2 in Cryptococcus neoformans.

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Gilbert, Nicole M; Baker, Lorina G; Specht, Charles A; Lodge, Jennifer K

2012-01-01

Cell wall proteins (CWPs) mediate important cellular processes in fungi, including adhesion, invasion, biofilm formation, and flocculation. The current model of fungal cell wall organization includes a major class of CWPs covalently bound to β-1,6-glucan via a remnant of a glycosylphosphatidylinositol (GPI) anchor. This model was established by studies of ascomycetes more than a decade ago, and relatively little work has been done with other fungi, although the presumption has been that proteins identified in the cell wall which contain a predicted GPI anchor are covalently linked to cell wall glucans. The pathogenic basidiomycete Cryptococcus neoformans encodes >50 putatively GPI-anchored proteins, some of which have been identified in the cell wall. One of these proteins is chitin deacetylase 2 (Cda2), an enzyme responsible for converting chitin to chitosan, a cell wall polymer recently established as a virulence factor for C. neoformans infection of mammalian hosts. Using a combination of biochemistry, molecular biology, and genetics, we show that Cda2 is GPI anchored to membranes but noncovalently associated with the cell wall by means independent of both its GPI anchor and β-1,6-glucan. We also show that Cda2 produces chitosan when localized to the plasma membrane, but association with the cell wall is not essential for this process, thereby providing insight into the mechanism of chitosan biosynthesis. These results increase our understanding of the surface of C. neoformans and provide models of cell walls likely applicable to other undercharacterized basidiomycete pathogenic fungi. The surface of a pathogenic microbe is a major interface with its host. In fungi, the outer surface consists of a complex matrix known as the cell wall, which includes polysaccharides, proteins, and other molecules. The mammalian host recognizes many of these surface molecules and mounts appropriate responses to combat the microbial infection. Cryptococcus neoformans is a

A Brazilian social bee must cultivate fungus to survive.

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Menezes, Cristiano; Vollet-Neto, Ayrton; Marsaioli, Anita Jocelyne; Zampieri, Davila; Fontoura, Isabela Cardoso; Luchessi, Augusto Ducati; Imperatriz-Fonseca, Vera Lucia

2015-11-02

The nests of social insects provide suitable microenvironments for many microorganisms as they offer stable environmental conditions and a rich source of food [1-4]. Microorganisms in turn may provide several benefits to their hosts, such as nutrients and protection against pathogens [1, 4-6]. Several examples of symbiosis between social insects and microorganisms have been found in ants and termites. These symbioses have driven the evolution of complex behaviors and nest structures associated with the culturing of the symbiotic microorganisms [5, 7, 8]. However, while much is known about these relationships in many species of ants and termites, symbiotic relationships between microorganisms and social bees have been poorly explored [3, 4, 9, 10]. Here, we report the first case of an obligatory relationship between the Brazilian stingless bee Scaptotrigona depilis and a fungus of the genus Monascus (Ascomycotina). Fungal mycelia growing on the provisioned food inside the brood cell are eaten by the larva. Larvae reared in vitro on sterilized larval food supplemented with fungal mycelia had a much higher survival rate (76%) compared to larvae reared under identical conditions but without fungal mycelia (8% survival). The fungus was found to originate from the material from which the brood cells are made. Since the bees recycle and transport this material between nests, fungus would be transferred to newly built cells and also to newly founded nests. This is the first report of a fungus cultivation mutualism in a social bee. Copyright © 2015 Elsevier Ltd. All rights reserved.

E-NTPDase and E-ADA activities in rats experimental infected by Cryptococcus neoformans.

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de Azevedo, Maria Isabel; Ferreiro, Laerte; Da Silva, Aleksandro S; Tonin, Alexandre A; Ruchel, Jader B; Rezer, João F P; França, Raqueli T; Zimmermann, Carine E P; Leal, Daniela B R; Duarte, Marta M M F; Lopes, Sonia T A; Flores, Mariana M; Fighera, Rafael; Santurio, Janio M

2014-11-07

Cryptococcus neoformans, the etiological agent of cryptococcosis, is an opportunistic fungal pathogen of immunocompromised individuals. The aim of this study was to evaluate the activities of E-NTPDase and E-ADA in rats experimentally infected by C. neoformans var. grubii. Adult rats (35) were divided in two groups: 18 for the control group (uninfected) (A), and 17 for the infected group (B). Each group was separated into three sub-groups (A1, A2, A3-B1, B2, B3), and samples were collected on 10, 20, and 30 days post-infection (PI). Leukocyte counts, IFN-γ, TNF-α, IgM, IgG levels, and E-NTPDase and E-ADA activities were analyzed. It was possible to observe that IgG and IgM seric levels of infected rats were significantly elevated (PADA activity had a significant reduction (PADA activity in lymphocytes increased significantly (PADA), concomitantly with an inflammatory response (increased levels of cytokines and immunoglobulins) associated with inflammatory infiltrates and histological lesions in the lung. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecular characterization and antifungal susceptibility of Cryptococcus neoformans strains collected from a single institution in Lima, Peru : Revista Iberoamericana De Micologia

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Bejar, V.; Tello, M.; Garcia, R.; Guevara, J. M.; Gonzales, S.; Vergaray, G.; Valencia, E.; Abanto, E.; Ortega-Loayza, A. G.; Hagen, F.; Gutierrez, E. L.

2015-01-01

Background: Cryptococcosis is a fungal infection with a worldwide distribution, mainly caused by Cryptococcus neoformans and Cryptococcus gattii. Aims: To molecularly characterize the mating-types, serotypes, genotypes and antifungal susceptibility profiles of a set of retrospectively isolated C.

Identification of Multiple Cryptococcal Fungicidal Drug Targets by Combined Gene Dosing and Drug Affinity Responsive Target Stability Screening

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Yoon-Dong Park

2016-08-01

Full Text Available Cryptococcus neoformans is a pathogenic fungus that is responsible for up to half a million cases of meningitis globally, especially in immunocompromised individuals. Common fungistatic drugs, such as fluconazole, are less toxic for patients but have low efficacy for initial therapy of the disease. Effective therapy against the disease is provided by the fungicidal drug amphotericin B; however, due to its high toxicity and the difficulty in administering its intravenous formulation, it is imperative to find new therapies targeting the fungus. The antiparasitic drug bithionol has been recently identified as having potent fungicidal activity. In this study, we used a combined gene dosing and drug affinity responsive target stability (GD-DARTS screen as well as protein modeling to identify a common drug binding site of bithionol within multiple NAD-dependent dehydrogenase drug targets. This combination genetic and proteomic method thus provides a powerful method for identifying novel fungicidal drug targets for further development.

Genomic and proteomic analyses of the fungus Arthrobotrys oligospora provide insights into nematode-trap formation.

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Yang, Jinkui; Wang, Lei; Ji, Xinglai; Feng, Yun; Li, Xiaomin; Zou, Chenggang; Xu, Jianping; Ren, Yan; Mi, Qili; Wu, Junli; Liu, Shuqun; Liu, Yu; Huang, Xiaowei; Wang, Haiyan; Niu, Xuemei; Li, Juan; Liang, Lianming; Luo, Yanlu; Ji, Kaifang; Zhou, Wei; Yu, Zefen; Li, Guohong; Liu, Yajun; Li, Lei; Qiao, Min; Feng, Lu; Zhang, Ke-Qin

2011-09-01

Nematode-trapping fungi are "carnivorous" and attack their hosts using specialized trapping devices. The morphological development of these traps is the key indicator of their switch from saprophytic to predacious lifestyles. Here, the genome of the nematode-trapping fungus Arthrobotrys oligospora Fres. (ATCC24927) was reported. The genome contains 40.07 Mb assembled sequence with 11,479 predicted genes. Comparative analysis showed that A. oligospora shared many more genes with pathogenic fungi than with non-pathogenic fungi. Specifically, compared to several sequenced ascomycete fungi, the A. oligospora genome has a larger number of pathogenicity-related genes in the subtilisin, cellulase, cellobiohydrolase, and pectinesterase gene families. Searching against the pathogen-host interaction gene database identified 398 homologous genes involved in pathogenicity in other fungi. The analysis of repetitive sequences provided evidence for repeat-induced point mutations in A. oligospora. Proteomic and quantitative PCR (qPCR) analyses revealed that 90 genes were significantly up-regulated at the early stage of trap-formation by nematode extracts and most of these genes were involved in translation, amino acid metabolism, carbohydrate metabolism, cell wall and membrane biogenesis. Based on the combined genomic, proteomic and qPCR data, a model for the formation of nematode trapping device in this fungus was proposed. In this model, multiple fungal signal transduction pathways are activated by its nematode prey to further regulate downstream genes associated with diverse cellular processes such as energy metabolism, biosynthesis of the cell wall and adhesive proteins, cell division, glycerol accumulation and peroxisome biogenesis. This study will facilitate the identification of pathogenicity-related genes and provide a broad foundation for understanding the molecular and evolutionary mechanisms underlying fungi-nematodes interactions.

Insertional mutagenesis in the vascular wilt pathogen Verticillium dahliae

NARCIS (Netherlands)

Santhanam, P.

2014-01-01

Vascular wilt diseases caused by soil-borne pathogens are among the most

devastating plant diseases worldwide. The ascomycete fungus Verticillium dahliae

causes vascular wilt diseases in hundreds of dicotyledonous plant species, including

important crops such as eggplant,

Autodissemination of the entomopathogenic fungus Metarhizium anisopliae amongst adults of the malaria vector anopheles gambiae s.s.

NARCIS (Netherlands)

Scholte, E.J.; Knols, B.G.J.; Takken, W.

2004-01-01

Background - The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent for adult African malaria vectors. In the laboratory, work was carried out to assess whether horizontal transmission of the pathogen can take place during copulation, as this would enhance the

Clinical and microbiological characteristics of cryptococcosis in Singapore: predominance of Cryptococcus neoformans compared with Cryptococcus gattii.

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Chan, Monica; Lye, David; Win, Mar Kyaw; Chow, Angela; Barkham, Tim

2014-09-01

To describe the clinical features, treatments, outcomes, and subtype prevalence of cryptococcosis in Singapore. All patients with laboratory confirmed cryptococcal infections admitted from 1999 to 2007 to a teaching hospital in Singapore were reviewed retrospectively. Identification and molecular types of Cryptococcus neoformans variants and Cryptococcus gattii were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serotypes were inferred with a multiplex PCR method. Of 62 patients with cryptococcosis, C. neoformans var. grubii was the predominant subtype (in 95%), affecting mainly immunocompromised hosts (91%) with HIV infection (80%). Patients with HIV were younger (median age 36.5 vs. 49.5 years, p=0.006) and less likely to present with an altered mental status (14% vs. 50%, p=0.013). In contrast, delayed treatment (median 7 days vs. 2 days, p=0.03), pulmonary involvement (58% vs. 14%, p=0.03), and initial treatment with fluconazole (25% vs. 2%, p=0.02) were more common in HIV-negative patients. C. gattii was uncommon, affecting only three patients, all of whom were immunocompetent and had disseminated disease with pulmonary and neurological involvement. All C. gattii were RFLP type VG II, serotype B and all C. neoformans var. grubii were RFLP type VN I, serotype A, except for one that was RFLP type VN II. C. neoformans var. grubii, subtype VN I, was the predominant subtype in Singapore, infecting younger, mainly immunocompromised hosts with HIV. C. gattii was uncommon, causing pulmonary manifestations in older, immunocompetent patients and were RFLP type VG II. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

The yeast spectrum of the 'tea fungus Kombucha'.

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Mayser, P; Fromme, S; Leitzmann, C; Gründer, K

1995-01-01

The tea fungus 'Kombucha' is a symbiosis of Acetobacter, including Acetobacter xylinum as a characteristic species, and various yeasts. A characteristic yeast species or genus has not yet been identified. Kombucha is mainly cultivated in sugared black tea to produce a slightly acidulous effervescent beverage that is said to have several curative effects. In addition to sugar, the beverage contains small amounts of alcohol and various acids, including acetic acid, gluconic acid and lactic acid, as well as some antibiotic substances. To characterize the yeast spectrum with special consideration given to facultatively pathogenic yeasts, two commercially available specimens of tea fungus and 32 from private households in Germany were analysed by micromorphological and biochemical methods. Yeasts of the genera Brettanomyces, Zygosaccharomyces and Saccharomyces were identified in 56%, 29% and 26% respectively. The species Saccharomycodes ludwigii and Candida kefyr were only demonstrated in isolated cases. Furthermore, the tests revealed pellicle-forming yeasts such as Candida krusei or Issatchenkia orientalis/occidentalis as well as species of the apiculatus yeasts (Kloeckera, Hanseniaspora). Thus, the genus Brettanomyces may be a typical group of yeasts that are especially adapted to the environment of the tea fungus. However, to investigate further the beneficial effects of tea fungus, a spectrum of the other typical genera must be defined. Only three specimens showed definite contaminations. In one case, no yeasts could be isolated because of massive contamination with Penicillium spp. In the remaining two samples (from one household), Candida albicans was demonstrated. The low rate of contamination might be explained by protective mechanisms, such as formation of organic acids and antibiotic substances. Thus, subjects with a healthy metabolism do not need to be advised against cultivating Kombucha. However, those suffering from immunosuppression should preferably

Scanning electron microscopy of the interaction between Cryptococcus magnus and Colletotrichum gloeosporioides on papaya fruit Microscopia eletrônica de varredura da interação entre Cryptococcus magnus e Colletotrichum gloeosporioides em frutos de mamão

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Guy de Capdeville

2007-11-01

Full Text Available The objective of this work was to investigate possible modes of action of the yeast Cryptococcus magnus in controlling anthracnose (Colletotrichum gloeosporioides on post harvested papaya fruits. Scanning electron microscopy was used to analyze the effect of the yeast on inoculations done after harvest. Results showed that C. magnus is able to colonize wound surfaces much faster than the pathogen, outcompeting the later for space and probably for nutrients. In addition, C. magnus produces a flocculent matrix, which affects hyphae integrity. The competition for space and the production of substances that affect hyphae integrity are among the most important modes of action of this yeast.O objetivo deste trabalho foi investigar prováveis modos de ação da levedura Cryptococcus magnus, que resultam no controle da antracnose (Colletotrichum gloeosporioides em frutos de mamoeiro na póscolheita. A microscopia eletrônica de varredura foi utilizada para avaliar o efeito da levedura sobre inoculações realizadas após a colheita. Os resultados mostraram que C. magnus é capaz de colonizar a superfície de ferimentos nos frutos e vencer a competição por espaço e, provavelmente, por nutrientes. Além disso, C. magnus produz uma matriz de textura característica que afeta a integridade da hifa do patógeno. A competição por espaço e a produção de substâncias que afetam a integridade das hifas estão entre os mais importantes modos de ação desta levedura.

Interspecific Comparison and annotation of two complete mitochondrial genome sequences from the plant pathogenic fungus Mycosphaerella graminicola

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Millenbaugh, Bonnie A; Pangilinan, Jasmyn L.; Torriani, Stefano F.F.; Goodwin, Stephen B.; Kema, Gert H.J.; McDonald, Bruce A.

2007-12-07

The mitochondrial genomes of two isolates of the wheat pathogen Mycosphaerella graminicola were sequenced completely and compared to identify polymorphic regions. This organism is of interest because it is phylogenetically distant from other fungi with sequenced mitochondrial genomes and it has shown discordant patterns of nuclear and mitochondrial diversity. The mitochondrial genome of M. graminicola is a circular molecule of approximately 43,960 bp containing the typical genes coding for 14 proteins related to oxidative phosphorylation, one RNA polymerase, two rRNA genes and a set of 27 tRNAs. The mitochondrial DNA of M. graminicola lacks the gene encoding the putative ribosomal protein (rps5-like), commonly found in fungal mitochondrial genomes. Most of the tRNA genes were clustered with a gene order conserved with many other ascomycetes. A sample of thirty-five additional strains representing the known global mt diversity was partially sequenced to measure overall mitochondrial variability within the species. Little variation was found, confirming previous RFLP-based findings of low mitochondrial diversity. The mitochondrial sequence of M. graminicola is the first reported from the family Mycosphaerellaceae or the order Capnodiales. The sequence also provides a tool to better understand the development of fungicide resistance and the conflicting pattern of high nuclear and low mitochondrial diversity in global populations of this fungus.

Genotipificación de aislamientos clínicos del complejo Cryptococcus neoformans/Cryptococcus gattii obtenidos en el Hospital «Dr. Julio C. Perrando», de la ciudad de Resistencia (Chaco, Argentina

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Maria E Cattana

Full Text Available La criptococosis es una infección fúngica causada por levaduras del género Cryptococcus, particularmente las del complejo Cryptococcus neoformans/Cryptococcus gattii. El conocimiento sobre la casuística de la criptococosis en el nordeste argentino es exiguo y no se tiene información sobre los tipos moleculares circulantes. El objetivo de este estudio fue realizar la caracterización genética de los aislamientos pertenecientes al complejo C. neoformans/C. gattii obtenidos en el Hospital «Dr. Julio C. Perrando» de la ciudad de Resistencia (Chaco, Argentina, con el fin de determinar especie, variedad y genotipo. Durante dos años y un mes se estudiaron 26 aislamientos clínicos. Mediante métodos convencionales y moleculares, un aislamiento fue identificado como C. gattii genotipo VGI y los 25 restantes como C. neoformans var.grubii, 23 de los cuales correspondieron al genotipo VNI y dos al genotipo VNII. Estos datos son una contribución al conocimiento de la epidemiología de la criptococosis en la Argentina y el primer informe sobre genotipos del complejo C. neoformans/C. gattii de origen clínico en el nordeste argentino.

Phylogenetic analysis reveals a cryptic species Blastomyces gilchristii, sp. nov. within the human pathogenic fungus Blastomyces dermatitidis.

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Elizabeth M Brown

Full Text Available Analysis of the population genetic structure of microbial species is of fundamental importance to many scientific disciplines because it can identify cryptic species, reveal reproductive mode, and elucidate processes that contribute to pathogen evolution. Here, we examined the population genetic structure and geographic differentiation of the sexual, dimorphic fungus Blastomyces dermatitidis, the causative agent of blastomycosis.Criteria for Genealogical Concordance Phylogenetic Species Recognition (GCPSR applied to seven nuclear loci (arf6, chs2, drk1, fads, pyrF, tub1, and its-2 from 78 clinical and environmental isolates identified two previously unrecognized phylogenetic species. Four of seven single gene phylogenies examined (chs2, drk1, pyrF, and its-2 supported the separation of Phylogenetic Species 1 (PS1 and Phylogenetic Species 2 (PS2 which were also well differentiated in the concatenated chs2-drk1-fads-pyrF-tub1-arf6-its2 genealogy with all isolates falling into one of two evolutionarily independent lineages. Phylogenetic species were genetically distinct with interspecific divergence 4-fold greater than intraspecific divergence and a high Fst value (0.772, P<0.001 indicative of restricted gene flow between PS1 and PS2. Whereas panmixia expected of a single freely recombining population was not observed, recombination was detected when PS1 and PS2 were assessed separately, suggesting reproductive isolation. Random mating among PS1 isolates, which were distributed across North America, was only detected after partitioning isolates into six geographic regions. The PS2 population, found predominantly in the hyper-endemic regions of northwestern Ontario, Wisconsin, and Minnesota, contained a substantial clonal component with random mating detected only among unique genotypes in the population.These analyses provide evidence for a genetically divergent clade within Blastomyces dermatitidis, which we use to describe a novel species

A network approach to predict pathogenic genes for Fusarium graminearum.

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Liu, Xiaoping; Tang, Wei-Hua; Zhao, Xing-Ming; Chen, Luonan

2010-10-04

Fusarium graminearum is the pathogenic agent of Fusarium head blight (FHB), which is a destructive disease on wheat and barley, thereby causing huge economic loss and health problems to human by contaminating foods. Identifying pathogenic genes can shed light on pathogenesis underlying the interaction between F. graminearum and its plant host. However, it is difficult to detect pathogenic genes for this destructive pathogen by time-consuming and expensive molecular biological experiments in lab. On the other hand, computational methods provide an alternative way to solve this problem. Since pathogenesis is a complicated procedure that involves complex regulations and interactions, the molecular interaction network of F. graminearum can give clues to potential pathogenic genes. Furthermore, the gene expression data of F. graminearum before and after its invasion into plant host can also provide useful information. In this paper, a novel systems biology approach is presented to predict pathogenic genes of F. graminearum based on molecular interaction network and gene expression data. With a small number of known pathogenic genes as seed genes, a subnetwork that consists of potential pathogenic genes is identified from the protein-protein interaction network (PPIN) of F. graminearum, where the genes in the subnetwork are further required to be differentially expressed before and after the invasion of the pathogenic fungus. Therefore, the candidate genes in the subnetwork are expected to be involved in the same biological processes as seed genes, which imply that they are potential pathogenic genes. The prediction results show that most of the pathogenic genes of F. graminearum are enriched in two important signal transduction pathways, including G protein coupled receptor pathway and MAPK signaling pathway, which are known related to pathogenesis in other fungi. In addition, several pathogenic genes predicted by our method are verified in other pathogenic fungi, which

A network approach to predict pathogenic genes for Fusarium graminearum.

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Xiaoping Liu

Full Text Available Fusarium graminearum is the pathogenic agent of Fusarium head blight (FHB, which is a destructive disease on wheat and barley, thereby causing huge economic loss and health problems to human by contaminating foods. Identifying pathogenic genes can shed light on pathogenesis underlying the interaction between F. graminearum and its plant host. However, it is difficult to detect pathogenic genes for this destructive pathogen by time-consuming and expensive molecular biological experiments in lab. On the other hand, computational methods provide an alternative way to solve this problem. Since pathogenesis is a complicated procedure that involves complex regulations and interactions, the molecular interaction network of F. graminearum can give clues to potential pathogenic genes. Furthermore, the gene expression data of F. graminearum before and after its invasion into plant host can also provide useful information. In this paper, a novel systems biology approach is presented to predict pathogenic genes of F. graminearum based on molecular interaction network and gene expression data. With a small number of known pathogenic genes as seed genes, a subnetwork that consists of potential pathogenic genes is identified from the protein-protein interaction network (PPIN of F. graminearum, where the genes in the subnetwork are further required to be differentially expressed before and after the invasion of the pathogenic fungus. Therefore, the candidate genes in the subnetwork are expected to be involved in the same biological processes as seed genes, which imply that they are potential pathogenic genes. The prediction results show that most of the pathogenic genes of F. graminearum are enriched in two important signal transduction pathways, including G protein coupled receptor pathway and MAPK signaling pathway, which are known related to pathogenesis in other fungi. In addition, several pathogenic genes predicted by our method are verified in other

Evidence for acquisition of virulence effectors in pathogenic chytrids

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Summers Kyle

2011-07-01

Full Text Available Abstract Background The decline in amphibian populations across the world is frequently linked to the infection of the chytrid fungus Batrachochytrium dendrobatidis (Bd. This is particularly perplexing because Bd was only recently discovered in 1999 and no chytrid fungus had previously been identified as a vertebrate pathogen. Results In this study, we show that two large families of known virulence effector genes, crinkler (CRN proteins and serine peptidases, were acquired by Bd from oomycete pathogens and bacteria, respectively. These two families have been duplicated after their acquisition by Bd. Additional selection analyses indicate that both families evolved under strong positive selection, suggesting that they are involved in the adaptation of Bd to its hosts. Conclusions We propose that the acquisition of virulence effectors, in combination with habitat disruption and climate change, may have driven the Bd epidemics and the decline in amphibian populations. This finding provides a starting point for biochemical investigations of chytridiomycosis.

Defending against parasites: fungus-growing ants combine specialized behaviours and microbial symbionts to protect their fungus gardens.

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Little, Ainslie E F; Murakami, Takahiro; Mueller, Ulrich G; Currie, Cameron R

2006-03-22

Parasites influence host biology and population structure, and thus shape the evolution of their hosts. Parasites often accelerate the evolution of host defences, including direct defences such as evasion and sanitation and indirect defences such as the management of beneficial microbes that aid in the suppression or removal of pathogens. Fungus-growing ants are doubly burdened by parasites, needing to protect their crops as well as themselves from infection. We show that parasite removal from fungus gardens is more complex than previously realized. In response to infection of their fungal gardens by a specialized virulent parasite, ants gather and compress parasitic spores and hyphae in their infrabuccal pockets, then deposit the resulting pellet in piles near their gardens. We reveal that the ants' infrabuccal pocket functions as a specialized sterilization device, killing spores of the garden parasite Escovopsis. This is apparently achieved through a symbiotic association with actinomycetous bacteria in the infrabuccal pocket that produce antibiotics which inhibit Escovopsis. The use of the infrabuccal pocket as a receptacle to sequester Escovopsis, and as a location for antibiotic administration by the ants' bacterial mutualist, illustrates how the combination of behaviour and microbial symbionts can be a successful defence strategy for hosts.

Effects of the Chytrid fungus on the Tarahumara frog (Rana tarahumarae) in Arizona and Sonora, Mexico

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Stephen F. Hale; Philip C. Rosen; James L. Jarchow; Gregory A. Bradley

2005-01-01

We conducted histological analyses on museum specimens collected 1975-1999 from 10 sites in Arizona and Sonora to test for the pathogenic chytrid fungus (Batrachochytrium dendrobatidis) in ranid frogs, focusing on the Tarahumara frog (Rana tarahumarae). During 1981-2000, frogs displaying disease signs were found in the field, and...

Pathogenicity of Aspergillus westerdijkiae to females and oothecae of Periplaneta Americana

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Mariah Valente Baggio

2016-01-01

Full Text Available ABSTRACT: Cockroach control is performed by the application of chemical insecticides which exert high selective pressure on populations and introduces synthetic substances in the environment, motivating the search for other methods of control such as entomopathogenic fungi. The objectives of this study were to investigate the pathogenicity of the JAB 42 Aspergillus westerdijkiae to females and oothecae of Periplaneta americana and to demonstrate its mechanism of action on oothecae. Suspensions containing 106 to 108 conidia/ml were used to infect females and oothecae. Mortality and other variables such as scanning electron microscopy were used to demonstrate the mechanism of action of the fungus. The isolated JAB 42 A. westerdijkiae is pathogenic to oothecae of P. americana, with low capacity to kill females. Adhesion, germination, penetration and extrusion of the fungus on the cockroach oothecae were observed.

Entomopathogenicity and Biological Attributes of Himalayan Treasured Fungus Ophiocordyceps sinensis (Yarsagumba)

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Baral, Bikash

2017-01-01

Members of the entomophagous fungi are considered very crucial in the fungal domain relative to their natural phenomenon and economic perspectives; however, inadequate knowledge of their mechanisms of interaction keeps them lagging behind in parallel studies of fungi associated with agro-ecology, forest pathology and medical biology. Ophiocordyceps sinensis (syn. Cordyceps sinensis), an intricate fungus-caterpillar complex after it parasitizes the larva of the moth, is a highly prized medicinal fungus known widely for ages due to its peculiar biochemical assets. Recent technological innovations have significantly contributed a great deal to profiling the variable clinical importance of this fungus and other related fungi with similar medicinal potential. However, a detailed mechanism behind fungal pathogenicity and fungal-insect interactions seems rather ambiguous and is poorly justified, demanding special attention. The goal of the present review is to divulge an update on the published data and provides promising insights on different biological events that have remained underemphasized in previous reviews on fungal biology with relation to life-history trade-offs, host specialization and selection pressures. The infection of larvae by a fungus is not a unique event in Cordyceps; hence, other fungal species are also reviewed for effective comparison. Conceivably, the rationale and approaches behind the inheritance of pharmacological abilities acquired and stored within the insect framework at a time when they are completely hijacked and consumed by fungal parasites, and the molecular mechanisms involved therein, are clearly documented. PMID:29371523

Presence of Aspergillus sydowii, a pathogen of gorgonian sea fans in the marine sponge Spongia obscura.

Science.gov (United States)

Ein-Gil, Neta; Ilan, Micha; Carmeli, Shmuel; Smith, Garriet W; Pawlik, Joseph R; Yarden, Oded

2009-06-01

The fungus Aspergillus sydowii is the causative agent of epidemics that affect gorgonian corals (sea fans) and has significantly affected their populations in the Caribbean Sea. We have isolated a strain of A. sydowii from healthy marine sponges (Spongia obscura) collected in Bahamian inshore waters. After its identification on the basis of morphology, molecular markers and chemical profiling followed by pathogenicity tests, we found this strain to be highly similar to a strain isolated from diseased coral, and have shown the capacity of this fungus to persist in sponge environment. Our findings suggest that sponges have the possibility of being reservoirs of a potential marine pathogen.

A role for antioxidants in acclimation of marine derived pathogenic fungus (NIOCC 1) to salt stress

Digital Repository Service at National Institute of Oceanography (India)

Ravindran, C.; Varatharajan, G.R.; Rajasabapathy, R.; Vijayakanth, S.; HarishKumar, A.; Meena, R.M.

stresses were analyzed and discussed for their possible role in the stress mechanism. The marine derived fungus was identified as Phialosimplex genus, which is associated with infections in dogs. Thus the present study elucidates that the scavenging...

The sugarcane defense protein SUGARWIN2 causes cell death in Colletotrichum falcatum but not in non-pathogenic fungi.

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Flávia P Franco

Full Text Available Plants respond to pathogens and insect attacks by inducing and accumulating a large set of defense-related proteins. Two homologues of a barley wound-inducible protein (BARWIN have been characterized in sugarcane, SUGARWIN1 and SUGARWIN2 (sugarcane wound-inducible proteins. Induction of SUGARWINs occurs in response to Diatraea saccharalis damage but not to pathogen infection. In addition, the protein itself does not show any effect on insect development; instead, it has antimicrobial activities toward Fusarium verticillioides, an opportunistic fungus that usually occurs after D. saccharalis borer attacks on sugarcane. In this study, we sought to evaluate the specificity of SUGARWIN2 to better understand its mechanism of action against phytopathogens and the associations between fungi and insects that affect plants. We used Colletotrichum falcatum, a fungus that causes red rot disease in sugarcane fields infested by D. saccharalis, and Ceratocystis paradoxa, which causes pineapple disease in sugarcane. We also tested whether SUGARWIN2 is able to cause cell death in Aspergillus nidulans, a fungus that does not infect sugarcane, and in the model yeast Saccharomyces cerevisiae, which is used for bioethanol production. Recombinant SUGARWIN2 altered C. falcatum morphology by increasing vacuolization, points of fractures and a leak of intracellular material, leading to germling apoptosis. In C. paradoxa, SUGARWIN2 showed increased vacuolization in hyphae but did not kill the fungi. Neither the non-pathogenic fungus A. nidulans nor the yeast S. cerevisiae was affected by recombinant SUGARWIN2, suggesting that the protein is specific to sugarcane opportunistic fungal pathogens.

Identification of O-mannosylated virulence factors in Ustilago maydis.

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Alfonso Fernández-Álvarez

Full Text Available The O-mannosyltransferase Pmt4 has emerged as crucial for fungal virulence in the animal pathogens Candida albicans or Cryptococcus neoformans as well as in the phytopathogenic fungus Ustilago maydis. Pmt4 O-mannosylates specific target proteins at the Endoplasmic Reticulum. Therefore a deficient O-mannosylation of these target proteins must be responsible for the loss of pathogenicity in pmt4 mutants. Taking advantage of the characteristics described for Pmt4 substrates in Saccharomyces cerevisiae, we performed a proteome-wide bioinformatic approach to identify putative Pmt4 targets in the corn smut fungus U. maydis and validated Pmt4-mediated glycosylation of candidate proteins by electrophoretic mobility shift assays. We found that the signalling mucin Msb2, which regulates appressorium differentiation upstream of the pathogenicity-related MAP kinase cascade, is O-mannosylated by Pmt4. The epistatic relationship of pmt4 and msb2 showed that both are likely to act in the same pathway. Furthermore, constitutive activation of the MAP kinase cascade restored appressorium development in pmt4 mutants, suggesting that during the initial phase of infection the failure to O-mannosylate Msb2 is responsible for the virulence defect of pmt4 mutants. On the other hand we demonstrate that during later stages of pathogenic development Pmt4 affects virulence independently of Msb2, probably by modifying secreted effector proteins. Pit1, a protein required for fungal spreading inside the infected leaf, was also identified as a Pmt4 target. Thus, O-mannosylation of different target proteins affects various stages of pathogenic development in U. maydis.

Cryptococcus neoformans sexual reproduction is controlled by a quorum sensing peptide.

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Tian, Xiuyun; He, Guang-Jun; Hu, Pengjie; Chen, Lei; Tao, Changyu; Cui, Ying-Lu; Shen, Lan; Ke, Weixin; Xu, Haijiao; Zhao, Youbao; Xu, Qijiang; Bai, Fengyan; Wu, Bian; Yang, Ence; Lin, Xiaorong; Wang, Linqi

2018-06-01

Bacterial quorum sensing is a well-characterized communication system that governs a large variety of collective behaviours. By comparison, quorum sensing regulation in eukaryotic microbes remains poorly understood, especially its functional role in eukaryote-specific behaviours, such as sexual reproduction. Cryptococcus neoformans is a prevalent fungal pathogen that has two defined sexual cycles (bisexual and unisexual) and is a model organism for studying sexual reproduction in fungi. Here, we show that the quorum sensing peptide Qsp1 serves as an important signalling molecule for both forms of sexual reproduction. Qsp1 orchestrates various differentiation and molecular processes, including meiosis, the hallmark of sexual reproduction. It activates bisexual mating, at least in part through the control of pheromone, a signal necessary for bisexual activation. Notably, Qsp1 also plays a major role in the intercellular regulation of unisexual initiation and coordination, in which pheromone is not strictly required. Through a multi-layered genetic screening approach, we identified the atypical zinc finger regulator Cqs2 as an important component of the Qsp1 signalling cascade during both bisexual and unisexual reproduction. The absence of Cqs2 eliminates the Qsp1-stimulated mating response. Together, these findings extend the range of behaviours governed by quorum sensing to sexual development and meiosis.

Isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings.

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Soltani, Maryam; Bayat, Mansour; Hashemi, Seyed J; Zia, Mohammadali; Pestechian, Nader

2013-01-01

Invasive fungal infections cause considerable morbidity and mortality in immunocompromised hosts. Pigeon droppings could especially be a potential carrier in the spread of pathogenic yeasts and mold fungi into the environment. The objective of this study was to isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings. One hundred twenty samples of pigeon droppings were suspended 1:10 in saline solution and then cultured. Identification of C. neoformans was performed on bird seed agar, presence of a capsule on India ink preparation, urease production on urea agar medium and RapID yeast plus system. The identification of candida species was based on micro-morphological analysis on corn meal-Tween 80 agar, RapID yeast plus system and growth in CHROMagar candida. The identification of other fungi was based on macromorphologic, microscopic, biochemical and physiological characteristics. The highest frequency of yeasts and mold fungi were observed in Candida albicans 6.6% and Penicillium spp. 25%. The frequency rate of C. neoformans isolation was 2.5%. Several types of fungi are present in pigeon droppings that can spread in environment and transmit to children and elderly as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases.

Isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings

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Maryam Soltani

2013-01-01

Full Text Available Background: Invasive fungal infections cause considerable morbidity and mortality in immunocompromised hosts. Pigeon droppings could especially be a potential carrier in the spread of pathogenic yeasts and mold fungi into the environment. The objective of this study was to isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings. Materials and Methods: One hundred twenty samples of pigeon droppings were suspended 1:10 in saline solution and then cultured. Identification of C. neoformans was performed on bird seed agar, presence of a capsule on India ink preparation, urease production on urea agar medium and RapID yeast plus system. The identification of candida species was based on micro-morphological analysis on corn meal-Tween 80 agar, RapID yeast plus system and growth in CHROMagar candida. The identification of other fungi was based on macromorphologic, microscopic, biochemical and physiological characteristics. Results: The highest frequency of yeasts and mold fungi were observed in Candida albicans 6.6% and Penicillium spp. 25%. The frequency rate of C. neoformans isolation was 2.5%. Conclusion: Several types of fungi are present in pigeon droppings that can spread in environment and transmit to children and elderly as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases.

Geosmithia-Ophiostoma: a New Fungus-Fungus Association.

Science.gov (United States)

Pepori, Alessia L; Bettini, Priscilla P; Comparini, Cecilia; Sarrocco, Sabrina; Bonini, Anna; Frascella, Arcangela; Ghelardini, Luisa; Scala, Aniello; Vannacci, Giovanni; Santini, Alberto

2018-04-01

In Europe as in North America, elms are devastated by Dutch elm disease (DED), caused by the alien ascomycete Ophiostoma novo-ulmi. Pathogen dispersal and transmission are ensured by local species of bark beetles, which established a novel association with the fungus. Elm bark beetles also transport the Geosmithia fungi genus that is found in scolytids' galleries colonized by O. novo-ulmi. Widespread horizontal gene transfer between O. novo-ulmi and Geosmithia was recently observed. In order to define the relation between these two fungi in the DED pathosystem, O. novo-ulmi and Geosmithia species from elm, including a GFP-tagged strain, were grown in dual culture and mycelial interactions were observed by light and fluorescence microscopy. Growth and sporulation of O. novo-ulmi in the absence or presence of Geosmithia were compared. The impact of Geosmithia on DED severity was tested in vivo by co-inoculating Geosmithia and O. novo-ulmi in elms. A close and stable relation was observed between the two fungi, which may be classified as mycoparasitism by Geosmithia on O. novo-ulmi. These results prove the existence of a new component in the complex of organisms involved in DED, which might be capable of reducing the disease impact.

Infection of adult Aedes aegypti and Ae. albopictus mosquitoes with the entomopathogenic fungus Metarhizium anisopliae

NARCIS (Netherlands)

Scholte, E.J.; Takken, W.; Knols, B.G.J.

2007-01-01

This study describes a laboratory investigation on the use of the insect-pathogenic fungus Metarhizium anisopliae against adult Aedes aegypti and Ae. albopictus mosquitoes. At a dosage of 1.6 × 1010 conidia/m2, applied on material that served as a mosquito resting site, an average of 87.1 ± 2.65% of

Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America

Science.gov (United States)

Chestnut, Tara E.; Anderson, Chauncey; Popa, Radu; Blaustein, Andrew R.; Voytek, Mary; Olson, Deanna H.; Kirshtein, Julie

2014-01-01

Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd), is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L−1. The highest density observed was ∼3 million zoospores L−1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure

In vivo expression of genes in the entomopathogenic fungus Beauveria bassiana during infection of lepidopteran larvae.

Science.gov (United States)

Galidevara, Sandhya; Reineke, Annette; Koduru, Uma Devi

2016-05-01

The entomopathogenic fungus Beauveria bassiana (Bals.) Vuillemin is commercially available as a bio insecticide. The expression of three genes previously identified to have a role in pathogenicity in in vitro studies was validated in vivo in three lepidopteran insects infected with B. bassiana. Expression of all three genes was observed in all the tested insects starting from 48 or 72h to 10d post infection corroborating their role in pathogenicity. We suggest that it is essential to test the expression of putative pathogenicity genes both in vitro and in vivo to understand their role in different insect species. Copyright © 2016 Elsevier Inc. All rights reserved.

Suppressive effects of mycoviral proteins encoded by Magnaporthe oryzae chrysovirus 1 strain A on conidial germination of the rice blast fungus.

Science.gov (United States)

Urayama, Syun-Ichi; Kimura, Yuri; Katoh, Yu; Ohta, Tomoko; Onozuka, Nobuya; Fukuhara, Toshiyuki; Arie, Tsutomu; Teraoka, Tohru; Komatsu, Ken; Moriyama, Hiromitsu

2016-09-02

Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is the causal agent of growth repression and attenuated virulence (hypovirulence) of the rice blast fungus, Magnaporthe oryzae. We previously revealed that heterologous expression of the MoCV1-A ORF4 protein resulted in cytological damage to the yeasts Saccharomyces cerevisiae and Cryptococcus neoformans. Since the ORF4 protein is one of the components of viral particles, we evaluated the inhibitory effects of the purified virus particle against the conidial germination of M. oryzae, and confirmed its suppressive effects. Recombinant MoCV1-A ORF4 protein produced in Pichia pastoris was also effective for suppression of conidial germination of M. oryzae. MoCV1-A ORF4 protein sequence showed significant similarity to 6 related mycoviral proteins; Botrysphaeria dothidea chrysovirus 1, two Fusarium graminearum viruses, Fusarium oxysporum f. sp. dianthi mycovirus 1, Penicillium janczewski chrysovirus and Agaricus bisporus virus 1 in the Chrysoviridae family. Multiple alignments of the ORF4-related protein sequences showed that their central regions (210-591 aa in MoCV1-A ORF4) are relatively conserved. Indeed, yeast transformants expressing the conserved central region of MoCV1-A ORF4 protein (325-575 aa) showed similar impaired growth phenotypes as those observed in yeasts expressing the full-length MoCV1-A ORF4 protein. These data suggest that the mycovirus itself and its encoded viral protein can be useful as anti-fungal proteins to control rice blast disease caused by M. oryzae and other pathogenic fungi. Copyright © 2016 Elsevier B.V. All rights reserved.

DNA probe for strain typing of Cryptococcus neoformans.

OpenAIRE

Varma, A; Kwon-Chung, K J

1992-01-01

A 7-kb linear plasmid, harbored by a URA5 transformant, hybridized to all the chromosomes of Cryptococcus neoformans separated by contour-clamped homogeneous electric field electrophoresis. Its linear maintenance was determined to have been facilitated by the presence of telomere-like sequences at its free ends. Hybridization of this plasmid to AccI-digested genomic DNAs of 26 C. neoformans strains generated 21 unique DNA fingerprints. The DNA fingerprints of isolates within the same serotype...

Phosphorus uptake of an arbuscular mycorrhizal fungus is not effected by the biocontrol bacterium ¤Burkholderia cepacia¤

DEFF Research Database (Denmark)

Ravnskov, S.; Larsen, J.; Jakobsen, I.

2002-01-01

The biocontrol bacterium Burkholderia cepacia is known to suppress a broad range of root pathogenic fungi, while its impact on other beneficial non-target organisms such as arbuscular mycorrhizal (AM) fungi is unknown. Direct interactions between five B. cepacia strains and the AM fungus, Glomus ...

Infection of the malaria mosquito Anopheles gambiae with the entomopathogenic fungus Metarhizium anisopliae reduces blood feeding and fecundity

NARCIS (Netherlands)

Scholte, E.J.; Knols, B.G.J.; Takken, W.

2006-01-01

The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent against adult African malaria vectors. In addition to causing significant mortality, this pathogen is known to cause reductions in feeding and fecundity in a range of insects. In the present study we

Hydroxyurea treatment inhibits proliferation of Cryptococcus neoformans in mice

Directory of Open Access Journals (Sweden)

Kaushlendra eTripathi

2012-05-01

Full Text Available The fungal pathogen Cryptococcus neoformans (Cn is a serious threat to immunocompromised individuals, especially for HIV patients who develop meningoencephalitis. For effective cryptococcal treatment, novel antifungal drugs or innovative combination therapies are needed. Recently, sphingolipids have emerged as important bioactive molecules in the regulation of microbial pathogenesis. Previously we reported that the sphingolipid pathway gene, ISC1, which is responsible for ceramide production, is a major virulence factor in Cn infection. Here we report our studies of the role of ISC1 during genotoxic stress induced by the antineoplastic hydroxyurea (HU and methylmethane sulfonate (MMS, which affect DNA replication and genome integrity. We observed that Cn cells lacking ISC1 are highly sensitive to HU and MMS in a rich culture medium. HU affected cell division of Cn cells lacking the ISC1 gene, resulting in cell clusters. Cn ISC1, when expressed in a Saccharomyces cerevisiae (Sc strain lacking its own ISC1 gene, restored HU resistance. In macrophage-like cells, although HU affected the proliferation of WT Cn cells by 50% at the concentration tested, HU completely inhibited Cn isc1-delta cell proliferation. Interestingly, our preliminary data show that mice infected with WT or Cn isc1-delta cells and subsequently treated with HU had longer lifespans than untreated, infected control mice. Our work suggests that the sphingolipid pathway gene, ISC1, is a likely target for combination therapy with traditional drugs such as HU.

Comparative Genomics Reveals the Core Gene Toolbox for the Fungus-Insect Symbiosis

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Stata, Matt; Wang, Wei; White, Merlin M.; Moncalvo, Jean-Marc

2018-01-01

ABSTRACT Modern genomics has shed light on many entomopathogenic fungi and expanded our knowledge widely; however, little is known about the genomic features of the insect-commensal fungi. Harpellales are obligate commensals living in the digestive tracts of disease-bearing insects (black flies, midges, and mosquitoes). In this study, we produced and annotated whole-genome sequences of nine Harpellales taxa and conducted the first comparative analyses to infer the genomic diversity within the members of the Harpellales. The genomes of the insect gut fungi feature low (26% to 37%) GC content and large genome size variations (25 to 102 Mb). Further comparisons with insect-pathogenic fungi (from both Ascomycota and Zoopagomycota), as well as with free-living relatives (as negative controls), helped to identify a gene toolbox that is essential to the fungus-insect symbiosis. The results not only narrow the genomic scope of fungus-insect interactions from several thousands to eight core players but also distinguish host invasion strategies employed by insect pathogens and commensals. The genomic content suggests that insect commensal fungi rely mostly on adhesion protein anchors that target digestive system, while entomopathogenic fungi have higher numbers of transmembrane helices, signal peptides, and pathogen-host interaction (PHI) genes across the whole genome and enrich genes as well as functional domains to inactivate the host inflammation system and suppress the host defense. Phylogenomic analyses have revealed that genome sizes of Harpellales fungi vary among lineages with an integer-multiple pattern, which implies that ancient genome duplications may have occurred within the gut of insects. PMID:29764946

Transcriptomic insight into pathogenicity-associated factors of Conidiobolus obscurus, an obligate aphid-pathogenic fungus belonging to Entomopthoromycota.

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Wang, Jianghong; Zhou, Xiang; Guo, Kai; Zhang, Xinqi; Lin, Haiping; Montalva, Cristian

2018-01-16

Conidiobolus obscurus is a widespread fungal entomopathogen with aphid biocontrol potential. This study focused on a de novo transcriptomic analysis of C. obscurus. A number of pathogenicity-associated factors were annotated for the first time from the assembled 17 231 fungal unigenes, including those encoding subtilisin-like proteolytic enzymes (Pr1s), trypsin-like proteases, metalloproteases, carboxypeptidases and endochitinases. Many of these genes were transcriptionally up-regulated by at least twofold in mycotized cadavers compared with the in vitro fungal cultures. The resultant transcriptomic database was validated by the transcript levels of three selected pathogenicity-related genes quantified from different in vivo and in vitro material in real-time quantitative polymerase chain reaction (PCR). The involvement of multiple Pr1 proteases in the first stage of fungal infection was also suggested. Interestingly, a unique cytolytic (Cyt)-like δ-endotoxin gene was highly expressed in both mycotized cadavers and fungal cultures, and was more or less distinct from its homologues in bacteria and other fungi. Our findings provide the first global insight into various pathogenicity-related genes in this obligate aphid pathogen and may help to develop novel biocontrol strategy against aphid pests. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis.

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Johann, Susana; Sá, Nívea P; Lima, Luciana A R S; Cisalpino, Patricia S; Cota, Betania B; Alves, Tânia M A; Siqueira, Ezequias P; Zani, Carlos L

2010-10-12

The aim of this study was to isolate and identify the antifungal compounds from the extracts of Schinus terebinthifolius (Anacardiaceae) against clinical isolates of the pathogenic fungus Paracoccidioides brasiliensis. The hexane and dichlomethane fractions from leaves and stems of S. terebinthifolius were fractionated using several chromatography techniques to afford four compounds. The compounds isolated from S. terebinthifolius were identified as schinol (1), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (2), quercetin (3), and kaempferol (4). Compounds 1 and 2 were active against different strains of P. brasiliensis, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 μg/ml. The isolate Pb 1578 was more sensitive to compound 1 with a MIC value of 7.5 μg/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. terebinthifolius were not able to inhibit cell wall synthesis or assembly using the sorbitol assay. This work reveals for the first time the occurrence of compound 2 and discloses activity of compounds 1 and 2 against several clinical isolates of P. brasiliensis. These results justify further studies to clarify the mechanisms of action of these compounds.

Morphological characteristics and pathogenicity of fungi associated with Roselle (Hibiscus Sabdariffa) diseases in Penang, Malaysia.

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Eslaminejad, Touba; Zakaria, Maziah

2011-11-01

Roselle, or Jamaica sorrel (Hibiscus sabdariffa) is a popular vegetable in many tropical regions, cultivated for its leaves, seeds, stems and calyces which, the dried calyces are used to prepare tea, syrup, jams and jellies and as beverages. The main objectives of this study were to identify and characterise fungal pathogens associated with Roselle diseases based on their morphological and cultural characteristics and to determine the pathogenicity of four fungi infecting Roselle seedlings, namely Phoma exigua, Fusarium nygamai, Fusarium tgcq and Rhizoctonia solani in Penang. A total of 200 fungal isolates were obtained from 90 samples of symptomatic Roselle tissues. The isolates were identified based on cultural and morphological characteristics, as well as their pathogenicity. The fungal pathogen most frequently isolated was P. exigua (present in 45% of the samples), followed by F. nygamai (25%), Rhizoctonia solani (19%) and F. camptoceras (11%). Pathogenicity tests showed that P. exigua, F. nygamai, F. camptoceras and R. solani were able to infect both wounded and unwounded seedlings with different degrees of severity as indicated by the Disease severity (DS). R. solani was the most pathogenic fungus affecting both wounded and unwounded Roselle seedlings, followed by P. exigua that was highly pathogenic on wounded seedlings. F. nygamai was less pathogenic while the least pathogenic fungus was F. camptoceras, infecting only the unwounded seedlings but, surprisingly, not the wounded plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

The entomopathogenic fungus Isaria fumosorosea and its compatibility with buprofezin: effects on the rugose spiraling whitefly Aleurodicus rugioperculatus

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The gumbo limbo or rugose spiraling whitefly is a new invasive pest of palms, woody ornamentals, and fruits in Florida. The pathogenicity of a naturally occurring entomopathogenic fungus, Isaria fumosorosea (PFR 97) is well known for its activity against commonly found whiteflies species in the regi...

New Rust Disease of Korean Willow (Salix koreensis) Caused by Melampsora yezoensis, Unrecorded Pathogen in Korea.

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Yun, Yeo Hong; Ahn, Geum Ran; Yoon, Seong Kwon; Kim, Hoo Hyun; Son, Seung Yeol; Kim, Seong Hwan

2016-12-01

During the growing season of 2015, leaf specimens with yellow rust spots were collected from Salix koreensis Andersson, known as Korean willow, in riverine areas in Cheonan, Korea. The fungus on S. koreensis was identified as the rust species, Melampsora yezoensis , based on the morphology of urediniospores observed by light and scanning electron microscopy, and the molecular properties of the internal transcribed spacer rDNA region. Pathogenicity tests confirmed that the urediniospores are the causal agent of the rust symptoms on the leaves and young stems of S. koreensis . Here, we report a new rust disease of S. koreensis caused by the rust fungus, M. yezoensis , a previously unrecorded rust pathogen in Korea.

Cloning and molecular characterization of the glyceraldehyde-3-phosphate dehydrogenase-encoding gene and cDNA from the plant pathogenic fungus Glomerella cingulata.

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Templeton, M D; Rikkerink, E H; Solon, S L; Crowhurst, R N

1992-12-01

The glyceraldehyde-3-phosphate dehydrogenase gene (gpdA) has been identified from a genomic DNA library prepared from the plant pathogenic fungus Glomerella cingulata. Nucleotide sequence data revealed that this gene codes for a putative 338-amino-acid protein encoded by two exons of 129 and 885 bp, separated by an intron 216 bp long. The 5' leader sequence is also spliced by an intron of 156 bp. A cDNA clone was prepared using the polymerase chain reaction, the sequence of which was used to confirm the presence of the intron in the coding sequence and the splicing of the 5' leader sequence. The transcriptional start point (tsp) was mapped at -253 nt from the site of the initiation of translation by primer extension and is adjacent to a 42-bp pyrimidine-rich region. The general structure of the 5' flanking region shows similarities to gpdA from Aspergillus nidulans. The putative protein product is 71-86% identical at the aa level to GPDs from Aspergillus nidulans, Cryphonectria parasitica, Curvularia lunata, Podospora anserina and Ustilago maydis.

PERIORBITAL NECROTIZING FASCIITIS DUE TO CRYPTOCOCCUS NEOFORMANS IN A HEALTHY-YOUNG MAN

NARCIS (Netherlands)

DOORENBOSBOT, ACC; HOOYMANS, JMM; BLANKSMA, LJ

1990-01-01

A case report is presented of a healthy 25-year-old man who developed a periorbital necrotising fasciitis after a trivial trauma with a wooden splinter. Necrotising fasciitis of the eyelids occurs rarely. Cryptococcus neoformans is not described as a causative factor of necrotizing fasciitis.

Fungal genome and mating system transitions facilitated by chromosomal translocations involving intercentromeric recombination.

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Sheng Sun

2017-08-01

Full Text Available Species within the human pathogenic Cryptococcus species complex are major threats to public health, causing approximately 1 million annual infections globally. Cryptococcus amylolentus is the most closely known related species of the pathogenic Cryptococcus species complex, and it is non-pathogenic. Additionally, while pathogenic Cryptococcus species have bipolar mating systems with a single large mating type (MAT locus that represents a derived state in Basidiomycetes, C. amylolentus has a tetrapolar mating system with 2 MAT loci (P/R and HD located on different chromosomes. Thus, studying C. amylolentus will shed light on the transition from tetrapolar to bipolar mating systems in the pathogenic Cryptococcus species, as well as its possible link with the origin and evolution of pathogenesis. In this study, we sequenced, assembled, and annotated the genomes of 2 C. amylolentus isolates, CBS6039 and CBS6273, which are sexual and interfertile. Genome comparison between the 2 C. amylolentus isolates identified the boundaries and the complete gene contents of the P/R and HD MAT loci. Bioinformatic and chromatin immunoprecipitation sequencing (ChIP-seq analyses revealed that, similar to those of the pathogenic Cryptococcus species, C. amylolentus has regional centromeres (CENs that are enriched with species-specific transposable and repetitive DNA elements. Additionally, we found that while neither the P/R nor the HD locus is physically closely linked to its centromere in C. amylolentus, and the regions between the MAT loci and their respective centromeres show overall synteny between the 2 genomes, both MAT loci exhibit genetic linkage to their respective centromere during meiosis, suggesting the presence of recombinational suppressors and/or epistatic gene interactions in the MAT-CEN intervening regions. Furthermore, genomic comparisons between C. amylolentus and related pathogenic Cryptococcus species provide evidence that multiple chromosomal

A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight

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Ibonne Aydee García-Romero

2006-07-01

Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.

Compatibility of the insect pathogenic fungus Beauveria bassiana with neem against sweetpotato whitefly, Bemisia tabaci, on eggplant

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A study on the compatibility of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) with neem was conducted against sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on eggplant. Initially, three concentrations of B. bassiana (106, 1...

Evaluación de varias técnicas de extracción de ADN de Cryptococcus spp. a partir de muestras ambientales.

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Alexandra Castañeda

2004-09-01

Full Text Available El género Cryptococcus comprende, al menos, 38 especies, pero sólo 3 se han informado como patógenas para el hombre y los animales: Cryptococcus laurentii, Cryptococcus albidus y Cryptococcus neoformans; esta última es la más frecuente. La infección se adquiere por la inhalación de los propágulos infectantes del medio ambiente. Los estudios del hábitat se han realizado con técnicas de extracción con soluciones tampón y cultivos en medios selectivos. El objetivo del trabajo fue evaluar varias técnicas de extracción del ADN de Cryptococcus spp. a partir de muestras ambientales. Como controles se emplearon aislamientos de C. neoformans, C. albidus, C. laurentii y Paracoccidiodes brasiliensis. Se emplearon vermiculitas, suelos contaminados en el laboratorio con 10 a 106 blastoconidias/g y muestras naturalmente colonizadas con C. neoformans. El ADN se extrajo con métodos físicos, químicos y con un estuche comercial, y se purificó usando bloques de agarosa y columnas de sílica. Para la amplificación con PCR se emplearon los iniciadores CN4-CN5 específicos para C. neoformans. Sólo el estuche comercial permitió extraer y purificar el ADN de las muestras de suelos contaminados hasta una concentración de 10 blastoconidias/g de suelo y de una de las muestras naturalmente colonizadas. Con este trabajo se logró la extracción y amplificación de ADN de Cryptococcus spp. a partir de muestras ambientales lo cual constituye una herramienta importante para delimitar las áreas ecológicas de C. neoformans en nuestro país.

Novel Fungal Pathogenicity and Leaf Defense Strategies Are Revealed by Simultaneous Transcriptome Analysis of Colletotrichum fructicola and Strawberry Infected by This Fungus

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Liqing Zhang

2018-04-01

Full Text Available Colletotrichum fructicola, which is part of the C. gloeosporioides species complex, can cause anthracnose diseases in strawberries worldwide. However, the molecular interactions between C. fructicola and strawberry are largely unknown. A deep RNA-sequencing approach was applied to gain insights into the pathogenicity mechanisms of C. fructicola and the defense response of strawberry plants at different stages of infection. The transcriptome data showed stage-specific transcription accompanied by a step-by-step strawberry defense response and the evasion of this defense system by fungus. Fungal genes involved in plant cell wall degradation, secondary metabolism, and detoxification were up-regulated at different stage of infection. Most importantly, C. fructicola infection was accompanied by a large number of highly expressed effectors. Four new identified effectors function in the suppression of Bax-mediated programmed cell death. Strawberry utilizes pathogen-associated molecular patterns (PAMP-triggered immunity and effector-triggered immunity to prevent C. fructicola invasion, followed by the initiation of downstream innate immunity. The up-regulation of genes related to salicylic acid provided evidence that salicylic acid signaling may serve as the core defense signaling mechanism, while jasmonic acid and ethylene pathways were largely inhibited by C. fructicola. The necrotrophic stage displayed a significant up-regulation of genes involved in reactive oxygen species activation. Collectively, the transcriptomic data of both C. fructicola and strawberry shows that even though plants build a multilayered defense against infection, C. fructicola employs a series of escape or antagonizing mechanisms to successfully infect host cells.

Life History Responses and Gene Expression Profiles of the Nematode Pristionchus pacificus Cultured on Cryptococcus Yeasts.

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Gaurav V Sanghvi

Full Text Available Nematodes, the earth's most abundant metazoa are found in all ecosystems. In order to survive in diverse environments, they have evolved distinct feeding strategies and they can use different food sources. While some nematodes are specialists, including parasites of plants and animals, others such as Pristionchus pacificus are omnivorous feeders, which can live on a diet of bacteria, protozoans, fungi or yeast. In the wild, P. pacificus is often found in a necromenic association with beetles and is known to be able to feed on a variety of microbes as well as on nematode prey. However, in laboratory studies Escherichia coli OP50 has been used as standard food source, similar to investigations in Caenorhabditis elegans and it is unclear to what extent this biases the obtained results and how relevant findings are in real nature. To gain first insight into the variation in traits induced by a non-bacterial food source, we study Pristionchus-fungi interactions under laboratory conditions. After screening different yeast strains, we were able to maintain P. pacificus for at least 50-60 generations on Cryptococcus albidus and Cryptococcus curvatus. We describe life history traits of P. pacificus on both yeast strains, including developmental timing, survival and brood size. Despite a slight developmental delay and problems to digest yeast cells, which are both reflected at a transcriptomic level, all analyses support the potential of Cryptococcus strains as food source for P. pacificus. In summary, our work establishes two Cryptococcus strains as alternative food source for P. pacificus and shows change in various developmental, physiological and morphological traits, including the transcriptomic profiles.

Cloning and characterization of a glutathione S-transferase homologue from the plant pathogenic fungus Botrytis cinerea

NARCIS (Netherlands)

Prins, T.W.; Wagemakers, L.; Schouten, A.; Kan, van J.A.L.

2000-01-01

A gene was cloned from Botrytis cinerea that encodes a protein homologous to glutathione S-transferase (GST). The gene, denominated Bcgst1, is present in a single copy and represents the first example of such a gene from a filamentous fungus. The biochemical function of GSTs is to conjugate toxic

HYR1-mediated detoxification of reactive oxygen species is required for full virulence in the rice blast fungus.

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Kun Huang

2011-04-01

Full Text Available During plant-pathogen interactions, the plant may mount several types of defense responses to either block the pathogen completely or ameliorate the amount of disease. Such responses include release of reactive oxygen species (ROS to attack the pathogen, as well as formation of cell wall appositions (CWAs to physically block pathogen penetration. A successful pathogen will likely have its own ROS detoxification mechanisms to cope with this inhospitable environment. Here, we report one such candidate mechanism in the rice blast fungus, Magnaporthe oryzae, governed by a gene we refer to as MoHYR1. This gene (MGG_07460 encodes a glutathione peroxidase (GSHPx domain, and its homologue in yeast was reported to specifically detoxify phospholipid peroxides. To characterize this gene in M. oryzae, we generated a deletion mutantΔhyr1 which showed growth inhibition with increased amounts of hydrogen peroxide (H₂O₂. Moreover, we observed that the fungal mutants had a decreased ability to tolerate ROS generated by a susceptible plant, including ROS found associated with CWAs. Ultimately, this resulted in significantly smaller lesion sizes on both barley and rice. In order to determine how this gene interacts with other (ROS scavenging-related genes in M. oryzae, we compared expression levels of ten genes in mutant versus wild type with and without H₂O₂. Our results indicated that the HYR1 gene was important for allowing the fungus to tolerate H₂O₂ in vitro and in planta and that this ability was directly related to fungal virulence.

[Biochemical basis of tolerance to osmotic stress in phytopathogenic fungus: The case of Macrophomina phaseolina (Tassi) Goid.

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Martínez-Villarreal, Rodolfo; Garza-Romero, Tamar S; Moreno-Medina, Víctor R; Hernández-Delgado, Sanjuana; Mayek-Pérez, Netzahualcoyotl

Fungus Macrophomina phaseolina (Tassi) Goid. is the causative agent of charcoal rot disease which causes significant yield losses in major crops such as maize, sorghum, soybean and common beans in Mexico. This fungus is a facultative parasite which shows broad ability to adapt itself to stressed environments where water deficits and/or high temperature stresses commonly occur. These environmental conditions are common for most cultivable lands throughout Mexico. Here we describe some basic facts related to the etiology and epidemiology of the fungus as well as to the importance of responses to stressed environments, particularly to water deficits, based on morphology and growth traits, as well as on physiology, biochemistry and pathogenicity of fungus M. phaseolina. To conclude, we show some perspectives related to future research into the genus, which emphasize the increasing need to improve the knowledge based on the application of both traditional and biotechnological tools in order to elucidate the mechanisms of resistance to environmental stress which can be extrapolated to other useful organisms to man. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Proteomic analysis reveals that iron availability alters the metabolic status of the pathogenic fungus Paracoccidioides brasiliensis.

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Ana F A Parente

Full Text Available Paracoccidioides brasiliensis is a thermodimorphic fungus and the causative agent of paracoccidioidomycosis (PCM. The ability of P. brasiliensis to uptake nutrients is fundamental for growth, but a reduction in the availability of iron and other nutrients is a host defense mechanism many pathogenic fungi must overcome. Thus, fungal mechanisms that scavenge iron from host may contribute to P. brasiliensis virulence. In order to better understand how P. brasiliensis adapts to iron starvation in the host we compared the two-dimensional (2D gel protein profile of yeast cells during iron starvation to that of iron rich condition. Protein spots were selected for comparative analysis based on the protein staining intensity as determined by image analysis. A total of 1752 protein spots were selected for comparison, and a total of 274 out of the 1752 protein spots were determined to have changed significantly in abundance due to iron depletion. Ninety six of the 274 proteins were grouped into the following functional categories; energy, metabolism, cell rescue, virulence, cell cycle, protein synthesis, protein fate, transcription, cellular communication, and cell fate. A correlation between protein and transcript levels was also discovered using quantitative RT-PCR analysis from RNA obtained from P. brasiliensis under iron restricting conditions and from yeast cells isolated from infected mouse spleens. In addition, western blot analysis and enzyme activity assays validated the differential regulation of proteins identified by 2-D gel analysis. We observed an increase in glycolytic pathway protein regulation while tricarboxylic acid cycle, glyoxylate and methylcitrate cycles, and electron transport chain proteins decreased in abundance under iron limiting conditions. These data suggest a remodeling of P. brasiliensis metabolism by prioritizing iron independent pathways.

Environmental distribution of Cryptococcus neoformans and C. gattii around the Mediterranean basin

NARCIS (Netherlands)

Cogliati, Massimo; D'Amicis, Roberta; Zani, Alberto; Montagna, Maria Teresa; Caggiano, Giuseppina; De Giglio, Osvalda; Balbino, Stella; De Donno, Antonella; Serio, Francesca; Susever, Serdar; Ergin, Cagri; Velegraki, Aristea; Ellabib, Mohamed S; Nardoni, Simona; Macci, Cristina; Oliveri, Salvatore; Trovato, Laura; Dipineto, Ludovico; Rickerts, Volker; McCormick-Smith, Ilka; Akcaglar, Sevim; Tore, Okan; Mlinaric-Missoni, Emilija; Bertout, Sebastien; Mallié, Michele; Martins, Maria da Luz; Vencà, Ana C F; Vieira, Maria L; Sampaio, Ana C; Pereira, Cheila; Griseo, Giuseppe; Romeo, Orazio; Ranque, Stéphane; Al-Yasiri, Mohammed H Y; Kaya, Meltem; Cerikcioglu, Nilgun; Marchese, Anna; Vezzulli, Luigi; Ilkit, Macit; Desnos-Ollivier, Marie; Pasquale, Vincenzo; Korem, Maya; Polacheck, Itzhack; Scopa, Antonio; Meyer, Wieland; Ferreira-Paim, Kennio; Hagen, Ferry; Theelen, Bart; Boekhout, Teun; Lockhart, Shawn R; Tintelnot, Kathrin; Tortorano, Anna Maria; Dromer, Françoise; Varma, Ashok; Kwon-Chung, Kyung J; Inácio, Joäo; Alonso, Beatriz; Colom, Maria F

In order to elucidate the distribution of Cryptococcus neoformans and C. gattii in the Mediterranean basin, an extensive environmental survey was carried out during 2012-2015. A total of 302 sites located in 12 countries were sampled, 6436 samples from 3765 trees were collected and 5% of trees were

Agrobacterium-mediated transformation of verticillium dahliae with gfr gene to study cotton-pathogen interaction using a novel inoculation method

International Nuclear Information System (INIS)

Li, F.; Bibi, N.; Fan, K.; Wang, M.

2016-01-01

Verticillium dahliae is a soil-born fungal pathogen which causes Verticillium wilt in economically important crops including cotton. We conducted a study to monitor the interaction between the fungus and cotton. V. dahliae was transformed with the gene encoding green fluorescent protein. The gene can be constitutively expressed and fluorescence was clearly visible in both hyphae and spores. Due to heterogeneous gene insertion, the growth rate, colony morphology and pathogenicity of fungus transformants showed differences compared with corresponding wild type. Similarly, quantitative real-time PCR analysis also indicated significant differences in the gene expression among different V. dahliae transformants. To study cotton-pathogen interaction, we devised a novel inoculation method and developed a successful infection by keeping GFP-expressed mycelial plug along with aseptic cotton seedlings. After 6-day inoculation, the LSM microscopic image showed that the fungus rapidly formed a mycelial network on the surface of the stems and colonized into plant tissue, displayed an intercellular infection pattern. The early events during cotton colonization by V. dahliae can be successfully observed in 10 days including the plant growth period. Besides, pathological changes of seedlings like tissue discoloration, wilting, stem dehiscence and necrosis can be clearly observed without the influences of soil and other microbes. This inoculation method provides a rapid, effective and environmental friendly technique for the study of cotton-pathogen interaction and identification of resistant plant cultivars. (author)

[A pediatric case of HIV who diagnosed by virtue of disseminated cryptococcus infection].

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Acar, Manolya; Sütçü, Murat; Aktürk, Hacer; Hançerli Törün, Selda; Karagöz, Nurinisa; Beka, Hayati; Yekeler, Ensar; Ağaçfidan, Ali; Salman, Nuran; Somer, Ayper

2016-07-01

Cryptococcus neoformans is an important opportunistic pathogen that causes serious mortality and morbidity in AIDS patients. Although its incidence has decreased with proper antiretroviral treatment (ART), it is still a major concern in areas with low socioeconomic HIV endemic countries with poor sources of therapy. In our country, pediatric HIV infection and so, HIV-related opportunistic infections are very rare. In order to pay attention to this unusual collaboration; herein, we presented a pediatric case who was diagnosed with HIV and disseminated cryptococcus infection concomitantly. A 6.5-year-old previously healthy girl has admitted to our hospital with the complaints of prolonged fever, cough and hemoptysis. On her physical examination she had oral candidiasis, generalized lymphadenopathy and hepatosplenomegaly. Laboratory findings were as follows; white blood cell count: 3170 µL (neutrophil: 2720 µL, lymphocyte: 366 µL), hemoglobin level: 7.8 gr/dl, hematocrit: 25.5% platelets: 170.000 µL, CRP: 15.2 mg/L and serum IgG level: 1865 mg/dl. Her anti-HIV test yielde,d positive result and confirmed by Western blot assay, together with a high viral load (HIV-RNA: 3.442.000 copies/ml). She was started ART (lamivudine, zidovudine and lopinavir/ritonavir combination) with the diagnosis of stage 3 HIV infection (AIDS). Posteroanterior chest radiograph showed mediastinal extension and nodular parenchyma. Since the patient was suspected to have pulmonary tuberculosis based on the clinical and radiological findings, empirical antituberculosis therapy was started. Because of the insistance of fever, three different blood specimens, bone marrow and gastric aspirates were collected for culture, in which all of them yielded C.neoformans growth. She was then diagnosed as disseminated cryptococcosis and treated with liposomal amphotericin B and fluconazole successfully. Although pediatric HIV infection is usually diagnosed secondary to maternal disease, it can rarely be

Meiosis Drives Extraordinary Genome Plasticity in the Haploid Fungal Plant Pathogen Mycosphaerella Graminicola

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Meiosis in the plant-pathogenic fungus Mycosphaerella graminicola results in eight ascospores due to a mitotic division following the two meiotic divisions. The transient diploid phase allows for recombination among homologous chromosomes. However, some chromosomes of M. graminicola lack homologs an...

Can smoking cause melanization of Cryptococcus neoformans in vivo?

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Sabesan, G.

2011-01-01

Full Text Available Earlier studies have reported on the ability of Cryptococcus neoformans to synthesize melanin from tobacco extracts / nicotine incorporated in to the medium. However a study on the utilization of components in tobacco smoke by C. neoformans for melanin production was unreported. The present study reports on ability of C. neoformans for melanization using tobacco smoke and therefore substantiate the possible link between smoking and pathogenecity in clinical cryptococcal infections as reported by several researchers.

Mesenteric cryptococcal granuloma in a dog caused by Cryptococcus neoformans var. grubii

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Rodrigues-Hoffmann A

2012-09-01

Full Text Available Jennifer R Cook, Karen E Russell, Kristin B Eden, Aline Rodrigues-HoffmannDepartment of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USAAbstract: Although cryptococcosis is usually associated with respiratory and neurologic signs in domestic species (such as sneeze, cough, nasal discharge, seizures, ataxia, clinical manifestations of the disease may be more subtle and nonspecific. A 3-year-old male castrated Boxer dog presented with a history of chronic vomiting, diarrhea, weight loss, and lethargy. At no time had respiratory or neurologic signs been noted by the owners or the primary care veterinarian. Palpation of an abdominal mass revealed an atypical lesion location: a large (16 × 9 × 7 cm mass at the root of the mesentery. Diagnosis was achieved through cytology of this mass and a positive serologic Cryptococcus capsular antigen titer; polymerase chain reaction was utilized for speciation of the abdominal isolate as Cryptococcus neoformans variety grubii. The animal was euthanized due to poor prognosis. After necropsy and histopathologic analysis, the mesenteric mass and associated lymph nodes were identified as large fungal granulomas. This is a rare manifestation of cryptococcosis, involving several visceral organs, with no remaining evidence of the route of entry of the organism. As prompt diagnosis of mycotic illness is paramount to successful management, this case indicates that cryptococcal infection should be considered as a differential diagnosis in dogs with gastrointestinal signs and lymphadenopathy. The protean nature of cryptococcosis is discussed within the context of a brief review of emerging and unresolved issues in pathogenesis.Keywords: Cryptococcus gattii, granuloma, lymphadenitis

Population Genetic Analysis Reveals a High Genetic Diversity in the Brazilian Cryptococcus gattii VGII Population and Shifts the Global Origin from the Amazon Rainforest to the Semi-arid Desert in the Northeast of Brazil.

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Souto, Ana C P; Bonfietti, Lucas X; Ferreira-Paim, Kennio; Trilles, Luciana; Martins, Marilena; Ribeiro-Alves, Marcelo; Pham, Cau D; Martins, Liline; Dos Santos, Wallace; Chang, Marilene; Brito-Santos, Fabio; Santos, Dayane C S; Fortes, Silvana; Lockhart, Shawn R; Wanke, Bodo; Melhem, Márcia S C; Lazéra, Márcia S; Meyer, Wieland

2016-08-01

Cryptococcus neoformans and Cryptococcus gattii are responsible globally for almost one million cryptococcosis cases yearly, mostly in immunocompromised patients, such as those living with HIV. Infections due to C. gattii have mainly been described in tropical and subtropical regions, but its adaptation to temperate regions was crucial in the species evolution and highlighted the importance of this pathogenic yeast in the context of disease. Cryptococcus gattii molecular type VGII has come to the forefront in connection with an on-going emergence in the Pacific North West of North America. Taking into account that previous work pointed towards South America as an origin of this species, the present work aimed to assess the genetic diversity within the Brazilian C. gattii VGII population in order to gain new insights into its origin and global dispersal from the South American continent using the ISHAM consensus MLST typing scheme. Our results corroborate the finding that the Brazilian C. gattii VGII population is highly diverse. The diversity is likely due to recombination generated from sexual reproduction, as evidenced by the presence of both mating types in clinical and environmental samples. The data presented herein strongly supports the emergence of highly virulent strains from ancestors in the Northern regions of Brazil, Amazonia and the Northeast. Numerous genotypes represent a link between Brazil and other parts of the world reinforcing South America as the most likely origin of the C. gattii VGII subtypes and their subsequent global spread, including their dispersal into North America, where they caused a major emergence.

Antifungal activity of eicosanoic acids isolated from the endophytic fungus Mycosphaerella sp. against Cryptococcus neoformans and C. gattii.

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Pereira, Cristiane Bigatti; Pereira de Sá, Nívea; Borelli, Beatriz Martins; Rosa, Carlos Augusto; Barbeira, Paulo Jorge Sanches; Cota, Betania Barros; Johann, Susana

2016-11-01

The antifungal effects of two eicosanoic acids, 2-amino-3,4-dihydroxy-2-25-(hydroxymethyl)-14-oxo-6,12-eicosenoic acid (compound 1) and myriocin (compound 2), isolated from Mycosphaerella sp. were evaluated against Cryptococcus neoformans and C. gattii. The compounds displayed antifungal activities against several isolates of C. neoformans and C. gattii, with minimal inhibitory concentration (MIC) values ranging from 0.49 to 7.82 μM for compound 1 and 0.48-1.95 μM for compound 2. In the checkerboard microtiter test, both compounds exhibited synergistic activity with amphotericin B against C. gattii. Ultrastructural analysis revealed several signs of damage in C. gattii and C. neoformans cells treated with compounds 1 and 2, including deformities in cell shape, depressions on the surface, and withered cells. The cells of C. gattii treated with compounds 1 and 2 showed less loss of cellular material in comparison to those treated with amphotericin B. The difference in cellular material loss increased in a test compound concentration-dependent manner. Consistent with this observation, compounds 1 and 2 were able to internalize propidium iodide (PI) in C. gattii cells. In addition, compound 2 induced the formation of several pseudohyphae, suggesting that it could reduce virulence in C. gattii cells. The study results show that these natural products led to membrane damage; however, this may not be the main target of action. These compounds have potential antifungal activity and could be useful in further studies for developing more effective combination therapies with amphotericin B and reducing side effects in patients. Copyright © 2016 Elsevier Ltd. All rights reserved.

Secretome of fungus-infected aphids documents high pathogen activity and weak host response

DEFF Research Database (Denmark)

Grell, Morten Nedergaard; Jensen, Annette Bruun; Olsen, Peter B.

2011-01-01

Discovery of novel secretome proteins contributes to the understanding of host-pathogen interactions. Here we report a rich diversity of secreted proteins from the interaction between grain aphids (host, insect order Hemiptera) and fungi of the order Entomophthorales (insect pathogens), made...

Wood and bark anatomy of young beech in relation to Cryptococcus attack

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David. Lonsdale

1983-01-01

Within a sample of European beech, partial resistance to attack by the beech scale, Cryptococcus fagisuga, was associated with a smooth bark which had a regular, vertical pattern in its surface 'growth lines'. Such bark contained relatively little lignified outer parenchyma, and the main stone cell layer was strongly developed. The '...

The Southeastern Asian house mouse (Mus musculus castaneus Linn.) as a new passenger host for Cryptococcus neoformans var. grubii molecular type VNI.

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Singh, Karuna; Rani, Jyoti; Neelabh; Rai, Govind Kumar; Singh, Major

2017-11-01

We describe Mus musculus castaneus as a new mammalian host for Cryptococcus neoformans var. grubii (VNI). Eighteen apparently healthy adults and pups of the rodent were collected from human dwellings in Varanasi, a city of India. Both clinical and behavioral examinations of the rodents did not reveal any sign of the disease. Among visceral organs, histological examination of only liver exhibited the presence of single celled, encapsulated, Southgate's mucicarmine positive fungal structures consistent with C. neoformans. Nevertheless, culture of tissue homogenates of brain, lungs, liver, and kidneys yielded white colonies on Sabouraud's dextrose agar and brown mucoid colonies of C. neoformans on Staib's and Tobacco agar media. The pathogen was isolated from habitat soil as well as fresh faeces of the animals. All isolates were urease positive, nitrate and canavanine-glycine bromothymol blue negative, exhibited phenoloxidase activity and grew at 37°C. The isolates were identified as C. neoformans var. grubii with ITS primers and unique marker (GACA)4. The pathogen when inoculated in immunosuppressed mice showed low pathogenicity. To our knowledge, we for the first time report case cluster of Mus musculus castaneus as new passenger host for C. neoformans var. grubii (VNI). © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Lethality of the entomogenous fungus Beauveria bassiana strain NI8 on Lygus lineolaris (Hemiptera: Miridae) and its possible impact on beneficial arthropods

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Bioassays were conducted to examine the pathogenicity of the fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) strain NI8 against Lygus lineolaris (Palisot de Beauvois) and its impact on natural enemies including Apis mellifera L., Crysoperla rufrilabris Burmeister, Orius insid...

Comprehensive proteomic analysis of the wheat pathogenic fungus Zymoseptoria tritici

DEFF Research Database (Denmark)

Yang, Fen; Yin, Qi

2016-01-01

Zymoseptoria tritici causes Septoria tritici blotch disease of wheat. To obtain a comprehensive protein dataset of this fungal pathogen, proteomes of Z. tritici growing in nutrient-limiting and rich media and in vivo at a late stage of wheat infection were fractionated by 1D gel or strong cation...

Pathogenicity of Metarhizium anisopliae (Deuteromycetes) and permethrin to Ixodes scapularis (Acari: Ixodidae) nymphs

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Hornbostel, V.L.; Zhioua, Elyes; Benjamin, Michael A.; Ginsberg, Howard S.; Ostfeld, Richard S.

2005-01-01

Effectiveness of the entomopathogenic fungus Metarhizium anisopliae, for controlling nymphal Ixodes scapularis, was tested in laboratory and field trials. In the laboratory, M. anisopliae (Metschnikoff) Sorokin strain ESC1 was moderately pathogenic, with an LC50 of 107 spores/ml and induced 70% mortality at 109 spores/ml. In a field study, however, 109 spores/ml M. anisopliae did not effectively control questing I. scapularis nymphs, and significant differences were not detected in pre- and post-treatment densities. For nymphs collected and returned to the laboratory for observation, mortality was low in treatment groups, ranging from 20 to 36%. To assess whether a chemical acaricide would synergistically enhance pathogenicity of the fungus, we challenged unfed nymphal I. scapularis with combinations of M. anisopliae and permethrin, a relatively safe pyrethroid acaricide, in two separate bioassays. Significant interactions between M. anisopliae and permethrin were not observed, supporting neither synergism nor antagonism.

Cryptococcus sp abdominal infection in a patient with acquired immunodeficiency under secondary prophylaxis with fluconazole; Infeccao abdominal por Cryptococcus sp em paciente com imunodeficiencia adquirida em uso de profilaxia secundaria com fluconazol

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Coutinho, Rosane Luiza; Zarehdinne, Monica [Infectologia do Hospital Eduardo de Menezes Belo Horizonte, MG (Brazil); Peixoto, Arley; Tardieu Junior, Jose [Medicina da Faculdade de Saude e Ecologia Humana - FASEH, Vespasiano, MG (Brazil); Pedroso, Enio Roberto Pietra [Departamento de Clinica Medica da Faculdade de Medicina da Universidade Federal de Minas Gerais - UFMG, Belo Horizonte, MG (Brazil)

2011-10-15

This paper reports on a Cryptococcus sp infection relapse in a patient with acquired immunodeficiency three years after the first episode, when her T CD4+ lymphocyte count was high and she was making regular use of antiretroviral drugs. (author)

Dissecting the molecular interactions between wheat and the fungal pathogen Zymoseptoria tritici

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Graeme James Kettles

2016-04-01

Full Text Available The Dothideomycete fungus Zymoseptoria tritici (previously known as Mycosphaerella graminicola and Septoria tritici is the causative agent of Septoria tritici leaf blotch (STB disease of wheat (Triticum aestivum L.. In Europe, STB is the most economically damaging disease of wheat, with an estimated ~€1 billion per year in fungicide expenditure directed towards its control. Here, an overview of our current understanding of the molecular events that occur during Z. tritici infection of wheat leaves is presented. On the host side, this includes the contribution of (1 the pathogen-associated molecular pattern-triggered immunity (PTI layer of the plant defence, and (2 major Stb resistance loci to Z. tritici resistance. On the pathogen side of the interaction, we consolidate evidence from recent bioinformatic, transcriptomic and proteomic studies that begin to explain the contribution of Z. tritici effector proteins to the biphasic lifestyle of the fungus. This includes the discovery of chitin-binding proteins in the Z. tritici secretome, which contribute to evasion of immune surveillance by this pathogen, and the possible existence of ‘necrotrophic’ effectors from Z. tritici, which may actively stimulate host recognition in a manner similar to related necrotrophic fungal pathogens. We finish by speculating on how some of these recent fundamental discoveries might be harnessed to help improve resistance to STB in the world’s second largest food crop.

Draft genome sequence of Cercospora sojina isolate S9, a fungus causing frogeye leaf spot (FLS disease of soybean

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Fanchang Zeng

2017-06-01

Full Text Available Fungi are the causal agents of many of the world's most serious plant diseases causing disastrous consequences for large-scale agricultural production. Pathogenicity genomic basis is complex in fungi as multicellular eukaryotic pathogens. The fungus Cercospora sojina is a plant pathogen that threatens global soybean supplies. Here, we report the genome sequence of C. sojina strain S9 and detect genome features and predicted genomic elements. The genome sequence of C. sojina is a valuable resource with potential in studying the fungal pathogenicity and soybean host resistance to frogeye leaf spot (FLS, which is caused by C. sojina. The C. sojina genome sequence has been deposited and available at DDBJ/EMBL/GenBank under the project accession number AHPQ00000000.

Real-Time PCR Detection of Dogwood Anthracnose Fungus in Historical Herbarium Specimens from Asia.

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Miller, Stephen; Masuya, Hayato; Zhang, Jian; Walsh, Emily; Zhang, Ning

2016-01-01

Cornus species (dogwoods) are popular ornamental trees and important understory plants in natural forests of northern hemisphere. Dogwood anthracnose, one of the major diseases affecting the native North American Cornus species, such as C. florida, is caused by the fungal pathogen Discula destructiva. The origin of this fungus is not known, but it is hypothesized that it was imported to North America with its host plants from Asia. In this study, a TaqMan real-time PCR assay was used to detect D. destructiva in dried herbarium and fresh Cornus samples. Several herbarium specimens from Japan and China were detected positive for D. destructiva, some of which were collected before the first report of the dogwood anthracnose in North America. Our findings further support that D. destructiva was introduced to North America from Asia where the fungus likely does not cause severe disease.

Generation of Reactive Oxygen Species via NOXa Is Important for Development and Pathogenicity of Mycosphaerella graminicola.

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Choi, Yoon-E; Lee, Changsu; Goodwin, Stephen B

2016-03-01

The ascomycete fungus Mycosphaerella graminicola (synonym Zymoseptoria tritici) is an important pathogen of wheat causing economically significant losses. The primary nutritional mode of this fungus is thought to be hemibiotrophic. This pathogenic lifestyle is associated with an early biotrophic stage of nutrient uptake followed by a necrotrophic stage aided possibly by production of a toxin or reactive oxygen species (ROS). In many other fungi, the genes CREA and AREA are important during the biotrophic stage of infection, while the NOXa gene product is important during necrotrophic growth. To test the hypothesis that these genes are important for pathogenicity of M. graminicola, we employed an over-expression strategy for the selected target genes CREA, AREA, and NOXa, which might function as regulators of nutrient acquisition or ROS generation. Increased expressions of CREA, AREA, and NOXa in M. graminicola were confirmed via quantitative real-time PCR and strains were subsequently assayed for pathogenicity. Among them, the NOXa over-expression strain, NO2, resulted in significantly increased virulence. Moreover, instead of the usual filamentous growth, we observed a predominance of yeast-like growth of NO2 which was correlated with ROS production. Our data indicate that ROS generation via NOXa is important to pathogenicity as well as development in M. graminicola.

A phenome-based functional analysis of transcription factors in the cereal head blight fungus, Fusarium graminearum.

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Hokyoung Son

2011-10-01

Full Text Available Fusarium graminearum is an important plant pathogen that causes head blight of major cereal crops. The fungus produces mycotoxins that are harmful to animal and human. In this study, a systematic analysis of 17 phenotypes of the mutants in 657 Fusarium graminearum genes encoding putative transcription factors (TFs resulted in a database of over 11,000 phenotypes (phenome. This database provides comprehensive insights into how this cereal pathogen of global significance regulates traits important for growth, development, stress response, pathogenesis, and toxin production and how transcriptional regulations of these traits are interconnected. In-depth analysis of TFs involved in sexual development revealed that mutations causing defects in perithecia development frequently affect multiple other phenotypes, and the TFs associated with sexual development tend to be highly conserved in the fungal kingdom. Besides providing many new insights into understanding the function of F. graminearum TFs, this mutant library and phenome will be a valuable resource for characterizing the gene expression network in this fungus and serve as a reference for studying how different fungi have evolved to control various cellular processes at the transcriptional level.

A Unique Fungal Two-Component System Regulates Stress Responses, Drug Sensitivity, Sexual Development, and Virulence of Cryptococcus neoformans

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Bahn, Yong-Sun; Kojima, Kaihei; Cox, Gary M.

2006-01-01

The stress-activated mitogen-activated protein kinase (MAPK) pathway is widely used by eukaryotic organisms as a central conduit via which cellular responses to the environment effect growth and differentiation. The basidiomycetous human fungal pathogen Cryptococcus neoformans uniquely uses the stress-activated Pbs2-Hog1 MAPK system to govern a plethora of cellular events, including stress responses, drug sensitivity, sexual reproduction, and virulence. Here, we characterized a fungal “two-component” system that controls these fundamental cellular functions via the Pbs2-Hog1 MAPK cascade. A typical response regulator, Ssk1, modulated all Hog1-dependent phenotypes by controlling Hog1 phosphorylation, indicating that Ssk1 is the major upstream signaling component of the Pbs2-Hog1 pathway. A second response regulator, Skn7, governs sensitivity to Na+ ions and the antifungal agent fludioxonil, negatively controls melanin production, and functions independently of Hog1 regulation. To control these response regulators, C. neoformans uses multiple sensor kinases, including two-component–like (Tco) 1 and Tco2. Tco1 and Tco2 play shared and distinct roles in stress responses and drug sensitivity through the Hog1 MAPK system. Furthermore, each sensor kinase mediates unique cellular functions for virulence and morphological differentiation. Our findings highlight unique adaptations of this global two-component MAPK signaling cascade in a ubiquitous human fungal pathogen. PMID:16672377

Occurrence of the amphibian pathogen Batrachochytrium dendrobatidis in the Pacific Northwest.

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C.A. Pearl; E.L. Bull; D.E. Green; J. Bowerman; M.J. Adams; A. Hyatt; W.H. Wente

2007-01-01

Chytridiomycosis (infection by the fungus Batrachochytrium dendrobatidis) is an emerging pathogen of amphibians that is associated with declines in at least four continents. We report results of disease screens from 271 field-sampled amphibians from Oregon and Washington. Chytridiomycosis was detected on 5 of 7 species and from 31 percent of all...

Development of a greenhouse-based inoculation protocol for the fungus Colletotrichum cereale pathogenic to annual bluegrass (Poa annua)

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The fungus Colletotrichum cereale incites anthracnose disease on Poa annua (annual bluegrass) turfgrass. Anthracnose disease is geographically widespread highly destructive, with infections by C. cereale resulting in extensive turfgrass loss. Comprehensive research aimed at controlling turfgrass a...

The cAMP Signaling and MAP Kinase Pathways in Plant Pathogenic Fungi

NARCIS (Netherlands)

Mehrabi, R.; Zhao, X.; Kim, Y.; Xu, J.R.

2009-01-01

The key components of the well conserved cyclic AMP signaling and MAP kinase pathways have been functionally characterized in the corn smut Ustilago maydis, rice blast fungus Magnaporthe grisea, and a few other fungal pathogens. In general, the cAMP signaling and the MAP kinase cascade homologous to

Comprehensive proteomic analysis of the wheat pathogenic fungus Zymoseptoria tritici.

Science.gov (United States)

Yang, Fen; Yin, Qi

2016-01-01

Zymoseptoria tritici causes Septoria tritici blotch disease of wheat. To obtain a comprehensive protein dataset of this fungal pathogen, proteomes of Z. tritici growing in nutrient-limiting and rich media and in vivo at a late stage of wheat infection were fractionated by 1D gel or strong cation exchange (SCX) chromatography and analyzed by LC-MS/MS. A total of 5731, 5376 and 3168 Z. tritici proteins were confidently identified from these conditions, respectively. Of these in vitro and in planta proteins, 9 and 11% were predicted to contain signal peptides, respectively. Functional classification analysis revealed the proteins were involved in the various cellular activities. Comparison of three distinct protein expression profiles demonstrates the elevated carbohydrate, lipid and secondary metabolisms, transport, protein processing and energy production specifically in the host environment, in contrast to the enhancement of signaling, defense, replication, transcription and cell division in vitro. The data provide useful targets towards a better understanding of the molecular basis of Z. tritici growth, development, stress response and pathogenicity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Differential divergences of obligately insect-pathogenic Entomophthora species from fly and aphid hosts.

Science.gov (United States)

Jensen, Annette Bruun; Eilenberg, Jørgen; López Lastra, Claudia

2009-11-01

Three DNA regions (ITS 1, LSU rRNA and GPD) of isolates from the insect-pathogenic fungus genus Entomophthora originating from different fly (Diptera) and aphid (Hemiptera) host taxa were sequenced. The results documented a large genetic diversity among the fly-pathogenic Entomophthora and only minor differences among aphid-pathogenic Entomophthora. The evolutionary time of divergence of the fly and the aphid host taxa included cannot account for this difference. The host-driven divergence of Entomophthora, therefore, has been much greater in flies than in aphids. Host-range differences or a recent host shift to aphid are possible explanations.

Molecular Characterization and Antimicrobial Activity of an Endolichenic Fungus, Aspergillus sp. Isolated from Parmelia caperata of Similipal Biosphere Reserve, India.

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Padhi, Srichandan; Das, Devaranjan; Panja, Suraj; Tayung, Kumananda

2017-06-01

Endolichenic fungi are microbes that inhabit healthy inner lichen tissues without any disease symptoms. They have been reported to produce new and interesting bioactive metabolites. In the present study, an endolichenic fungus frequently isolated from surface-sterilized lichen thallus of Parmelia caperata has been described. The fungus was identified as Aspergillus tubingensis based on morphological traits and ITS rDNA sequence. Crude metabolites extracted from the culture broth exhibited considerable antimicrobial activity against a panel of clinically significant human pathogens. The fungus showed optimum antimicrobial activity in PDB medium in day 7 of incubation period. PDB medium amended with 1 % NaCl and at alkaline pH was found to be optimal for antimicrobial metabolites production. Enhanced activity was observed when the fungus was exposed briefly to a heat shock of 60 °C during incubation. The metabolites showed optimum λ-max at 214 nm with an absorbance value of 1.589. Molecular characterization of the isolate was carried out by ITS phylogeny and ITS2 secondary structure analyses. The phylogenetic trees based on both ITS rDNA and ITS2 sequences showed the isolate within the clade A. tubingensis. Considering the ubiquity and ambiguity in identifying Aspergillus species of different lifestyles, a method to differentiate pathogenic and endophytic Aspergillus at species level was developed using ITS2 secondary structure analysis. The results showed common folding pattern in the secondary structures with a helix and a 5' dangling end found to be highly conserved. Certain features in the secondary structure like multi-bulges and a symmetric interior loop were observed to be unique which distinguish our isolate from other A. tubingensis.

Vaccine-mediated immune responses to experimental pulmonary Cryptococcus gattii infection in mice.

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Ashok K Chaturvedi

Full Text Available Cryptococcus gattii is a fungal pathogen that can cause life-threatening respiratory and disseminated infections in immune-competent and immune-suppressed individuals. Currently, there are no standardized vaccines against cryptococcosis in humans, underlying an urgent need for effective therapies and/or vaccines. In this study, we evaluated the efficacy of intranasal immunization with C. gattii cell wall associated (CW and/or cytoplasmic (CP protein preparations to induce protection against experimental pulmonary C. gattii infection in mice. BALB/c mice immunized with C. gattii CW and/or CP protein preparations exhibited a significant reduction in pulmonary fungal burden and prolonged survival following pulmonary challenge with C. gattii. Protection was associated with significantly increased pro-inflammatory and Th1-type cytokine recall responses, in vitro and increased C. gattii-specific antibody production in immunized mice challenged with C. gattii. A number of immunodominant proteins were identified following immunoblot analysis of C. gattii CW and CP protein preparations using sera from immunized mice. Immunization with a combined CW and CP protein preparation resulted in an early increase in pulmonary T cell infiltrates following challenge with C. gattii. Overall, our studies show that C. gattii CW and CP protein preparations contain antigens that may be included in a subunit vaccine to induce prolonged protection against pulmonary C. gattii infection.

Glycogen Metabolic Genes Are Involved in Trehalose-6-Phosphate Synthase-Mediated Regulation of Pathogenicity by the Rice Blast Fungus Magnaporthe oryzae

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Wilson, Richard A.; Wang, Zheng-Yi; Kershaw, Michael J.; Talbot, Nicholas J.

2013-01-01

The filamentous fungus Magnaporthe oryzae is the causal agent of rice blast disease. Here we show that glycogen metabolic genes play an important role in plant infection by M. oryzae. Targeted deletion of AGL1 and GPH1, which encode amyloglucosidase and glycogen phosphorylase, respectively, prevented mobilisation of glycogen stores during appressorium development and caused a significant reduction in the ability of M. oryzae to cause rice blast disease. By contrast, targeted mutation of GSN1, which encodes glycogen synthase, significantly reduced the synthesis of intracellular glycogen, but had no effect on fungal pathogenicity. We found that loss of AGL1 and GPH1 led to a reduction in expression of TPS1 and TPS3, which encode components of the trehalose-6-phosphate synthase complex, that acts as a genetic switch in M. oryzae. Tps1 responds to glucose-6-phosphate levels and the balance of NADP/NADPH to regulate virulence-associated gene expression, in association with Nmr transcriptional inhibitors. We show that deletion of the NMR3 transcriptional inhibitor gene partially restores virulence to a Δagl1Δgph1 mutant, suggesting that glycogen metabolic genes are necessary for operation of the NADPH-dependent genetic switch in M. oryzae. PMID:24098112

Rapid Methods for the Laboratory Identification of Pathogenic Microorganisms.

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1982-09-01

coli Hemophilus influenzae Bacillus anthracis Bacillus circulans Bacillus coagulans Bacillus cereus T Candida albicans Cryptococcus neoformans Legionel...reveree aide If neceeeary and Identify by block number) Lectins: Rapid Identification, Bacillus anthracisjCryptococcus " neoformans. Neisseria...field-type kit for the rapid identification of Bacillus anthracis. We have shown that certain lectins will selectively interact with B. anthracis

Patogenicidade de Helminthosporium oryzae a algumas espécies de gramíneas Pathogenicity of Helminthosporium oryzae against some grass species

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V.H. Artigiani Filho

1995-04-01

Full Text Available O fungo Helminthosporium oryzae é um patógeno do arroz. Devido a sua variabilidade patogênica, foi investigada a possibilidade deste fungo infectar outras gramíneas. Através de inoculação artificial, ficou demonstrada a capacidade deste patógeno provocar infecção em aveia, cana, centeio, sorgo, trigo, Brachiaria decumbens e Panicum maximum. Assim, estas espécies vegetais podem ser consideradas potenciais hospedeiros do fungo na natureza.Helminthosporium oryzae is a rice pathogen. Due to its variability in pathogenicity, the possibility of this fungus Infecting other grasses was investigated. The capacity of this pathogen was demonstrated to be able to infect oat, sugar-cane, rye, sorghum, wheat, Brachiaria decumbens and Panicum maximum through artificial inoculations. Therefore, those plant species can be considered potencial hosts for the fungus in nature.

Allelic exchange of pheromones and their receptors reprograms sexual identity in Cryptococcus neoformans.

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Brynne C Stanton

2010-02-01

Full Text Available Cell type specification is a fundamental process that all cells must carry out to ensure appropriate behaviors in response to environmental stimuli. In fungi, cell identity is critical for defining "sexes" known as mating types and is controlled by components of mating type (MAT loci. MAT-encoded genes function to define sexes via two distinct paradigms: 1 by controlling transcription of components common to both sexes, or 2 by expressing specially encoded factors (pheromones and their receptors that differ between mating types. The human fungal pathogen Cryptococcus neoformans has two mating types (a and alpha that are specified by an extremely unusual MAT locus. The complex architecture of this locus makes it impossible to predict which paradigm governs mating type. To identify the mechanism by which the C. neoformans sexes are determined, we created strains in which the pheromone and pheromone receptor from one mating type (a replaced the pheromone and pheromone receptor of the other (alpha. We discovered that these "alpha(a" cells effectively adopt a new mating type (that of a cells; they sense and respond to alpha factor, they elicit a mating response from alpha cells, and they fuse with alpha cells. In addition, alpha(a cells lose the alpha cell type-specific response to pheromone and do not form germ tubes, instead remaining spherical like a cells. Finally, we discovered that exogenous expression of the diploid/dikaryon-specific transcription factor Sxi2a could then promote complete sexual development in crosses between alpha and alpha(a strains. These data reveal that cell identity in C. neoformans is controlled fully by three kinds of MAT-encoded proteins: pheromones, pheromone receptors, and homeodomain proteins. Our findings establish the mechanisms for maintenance of distinct cell types and subsequent developmental behaviors in this unusual human fungal pathogen.

Allelic exchange of pheromones and their receptors reprograms sexual identity in Cryptococcus neoformans.

Science.gov (United States)

Stanton, Brynne C; Giles, Steven S; Staudt, Mark W; Kruzel, Emilia K; Hull, Christina M

2010-02-26

Cell type specification is a fundamental process that all cells must carry out to ensure appropriate behaviors in response to environmental stimuli. In fungi, cell identity is critical for defining "sexes" known as mating types and is controlled by components of mating type (MAT) loci. MAT-encoded genes function to define sexes via two distinct paradigms: 1) by controlling transcription of components common to both sexes, or 2) by expressing specially encoded factors (pheromones and their receptors) that differ between mating types. The human fungal pathogen Cryptococcus neoformans has two mating types (a and alpha) that are specified by an extremely unusual MAT locus. The complex architecture of this locus makes it impossible to predict which paradigm governs mating type. To identify the mechanism by which the C. neoformans sexes are determined, we created strains in which the pheromone and pheromone receptor from one mating type (a) replaced the pheromone and pheromone receptor of the other (alpha). We discovered that these "alpha(a)" cells effectively adopt a new mating type (that of a cells); they sense and respond to alpha factor, they elicit a mating response from alpha cells, and they fuse with alpha cells. In addition, alpha(a) cells lose the alpha cell type-specific response to pheromone and do not form germ tubes, instead remaining spherical like a cells. Finally, we discovered that exogenous expression of the diploid/dikaryon-specific transcription factor Sxi2a could then promote complete sexual development in crosses between alpha and alpha(a) strains. These data reveal that cell identity in C. neoformans is controlled fully by three kinds of MAT-encoded proteins: pheromones, pheromone receptors, and homeodomain proteins. Our findings establish the mechanisms for maintenance of distinct cell types and subsequent developmental behaviors in this unusual human fungal pathogen.

Draft Genome Sequence of the Dimorphic Fungus Sporothrix pallida, a Nonpathogenic Species Belonging to Sporothrix, a Genus Containing Agents of Human and Feline Sporotrichosis

NARCIS (Netherlands)

D'Alessandro, Enrico; Giosa, Domenico; Huang, Lilin; Zhang, Jing; Gao, Wenchao; Brankovics, Balázs; Oliveira, Manoel Marques Evangelista; Scordino, Fabio; Lo Passo, Carla; Criseo, Giuseppe; van Diepeningen, Anne D; Huang, Huaiqiu; de Hoog, G Sybren; Romeo, Orazio

2016-01-01

Sporothrix pallidais considered to be a mostly avirulent environmental fungus, phylogenetically closely related to the well-known pathogenSporothrix schenckii Here, we present the first assembly of its genome, which provides a valuable resource for future comparative genomic studies between

A two-dimensional proteome map of the aflatoxigenic fungus Aspergillus flavus.

Science.gov (United States)

Pechanova, Olga; Pechan, Tibor; Rodriguez, Jose M; Williams, W Paul; Brown, Ashli E

2013-05-01

The filamentous fungus Aspergillus flavus is an opportunistic soil-borne pathogen that produces aflatoxins, the most potent naturally occurring carcinogenic compounds known. This work represents the first gel-based profiling analysis of A. flavus proteome and establishes a 2D proteome map. Using 2DE and MALDI-TOF-MS/MS, we identified 538 mycelial proteins of the aflatoxigenic strain NRRL 3357, the majority of which were functionally annotated as related to various cellular metabolic and biosynthetic processes. Additionally, a few enzymes from the aflatoxin synthesis pathway were also identified. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular identity and prevalence of Cryptococcus spp. nasal carriage in asymptomatic feral cats in Italy.

Science.gov (United States)

Danesi, Patrizia; Furnari, Carmelo; Granato, Anna; Schivo, Alice; Otranto, Domenico; Capelli, Gioia; Cafarchia, Claudia

2014-10-01

Cryptococcosis is a life-threatening fungal disease that infects humans and animals worldwide. Inhalation of fungal particles from an environmental source can cause primary infection of the respiratory system. As animals can be considered a sentinel for human diseases, the aim of this study was to determine the prevalence and molecular identity of Cryptococcus spp. in the nasal cavity of feral cats. Cats from 162 urban and rural feral cat colonies were sampled over 3 years. Of 766 cats from which nasal swabs were obtained, Cryptococcus spp. were recovered from 95 (12.6%), including 37 C. magnus (4.8%), 16 C. albidus (2.0%), 15 C. carnescens (1.9%), 12 C. neoformans (1.6%), as well as C. oeirensis (n = 3), C. victoriae (n = 3), C. albidosimilis (n = 2), Filobasidium globisporum (n = 2), C. adeliensis (n = 1), C. flavescens (n = 1), C. dimnae (n = 1), C. saitoi (n = 1), and C. wieringae (n = 1) with prevalence feral cats may carry C. neoformans and other Cryptococcus species in their sinonasal cavity. Genotyping of the specific cryptococcal isolates provides a better understanding of the epidemiology of these yeasts. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Generalized antifungal activity and 454-screening of Pseudonocardia and Amycolatopsis bacteria in nests of fungus-growing ants

OpenAIRE

Sen, Ruchira; Ishak, Heather D.; Estrada, Dora; Dowd, Scot E.; Hong, Eunki; Mueller, Ulrich G.

2009-01-01

In many host-microbe mutualisms, hosts use beneficial metabolites supplied by microbial symbionts. Fungus-growing (attine) ants are thought to form such a mutualism with Pseudonocardia bacteria to derive antibiotics that specifically suppress the coevolving pathogen Escovopsis, which infects the ants' fungal gardens and reduces growth. Here we test 4 key assumptions of this Pseudonocardia-Escovopsis coevolution model. Culture-dependent and culture-independent (tag-encoded 454-pyrosequencing) ...

Function of VtPGIP in pathogenic fungus resistance of Vitis thunbergii

African Journals Online (AJOL)

edoja

2014-02-19

Feb 19, 2014 ... with pathogenic fungi and water were harvested, immediately frozen in liquid nitrogen, and stored at ... structure of the VtPGIP protein and molecular modeling were analyzed using Swiss-Pdb Viewer 3.7. Cloning of the VtPGIP ...

No sex in fungus-farming ants or their crops.

Science.gov (United States)

Himler, Anna G; Caldera, Eric J; Baer, Boris C; Fernández-Marín, Hermógenes; Mueller, Ulrich G

2009-07-22

Asexual reproduction imposes evolutionary handicaps on asexual species, rendering them prone to extinction, because asexual reproduction generates novel genotypes and purges deleterious mutations at lower rates than sexual reproduction. Here, we report the first case of complete asexuality in ants, the fungus-growing ant Mycocepurus smithii, where queens reproduce asexually but workers are sterile, which is doubly enigmatic because the clonal colonies of M. smithii also depend on clonal fungi for food. Degenerate female mating anatomy, extensive field and laboratory surveys, and DNA fingerprinting implicate complete asexuality in this widespread ant species. Maternally inherited bacteria (e.g. Wolbachia, Cardinium) and the fungal cultivars can be ruled out as agents inducing asexuality. M. smithii societies of clonal females provide a unique system to test theories of parent-offspring conflict and reproductive policing in social insects. Asexuality of both ant farmer and fungal crop challenges traditional views proposing that sexual farmer ants outpace coevolving sexual crop pathogens, and thus compensate for vulnerabilities of their asexual crops. Either the double asexuality of both farmer and crop may permit the host to fully exploit advantages of asexuality for unknown reasons or frequent switching between crops (symbiont reassociation) generates novel ant-fungus combinations, which may compensate for any evolutionary handicaps of asexuality in M. smithii.

[Features of interaction bacterial strains Micrococcus luteus LBK1 from plants varieties/hybrids cucumber and sweet pepper and with fungus Fusarium oxysporum Scelecht].

Science.gov (United States)

Parfeniuk, A; Sterlikova, O; Beznosko, I; Krut', V

2014-01-01

The article presents the results of studying the impact of bacterial strain M. luteus LBK1, stimulating the growth and development of plant varieties/hybrids of cucumber and sweet pepper on the intensity of sporulation of the fungus F. oxysporum Scelecht--fusariose rot pathogen.

Distribution and prevalence of crown rot pathogens affecting wheat crops in southern Chile

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Ernesto Moya-Elizondo

2015-03-01

Full Text Available Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L. crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W and Purranque (40°50'30" S; 73°22'03" W. Severity of crown rot disease was determined through visual assessment of the first internode of 20 tillers obtained from each field. Incidence of crown rot pathogens per field was determined by plating the 20 tillers on Petri plates with 20% potato dextrose agar amended with lactic acid (aPDA medium. Resulting fungal colonies from monoxenic culture were identified by morphological or molecular-assisted identification. Severity of crown rot varied between 11.3% and 80% for individual fields. Culture plate analysis showed 72.2% of stems were infected with some fungus. Fusarium avenaceum, F. graminearum, and F. culmorum, pathogens associated with Fusarium crown rot disease were isolated from 13.5% of tillers. Gaeumannomyces graminis, causal agent of take-all disease in cereals, was isolated from 11.1% of culms. Phaeosphaeria sp., an endophyte and possibly a non-pathogenic fungus, was isolated from 13.9% of tillers. Pathogenic fungi such as Rhizoctonia spp. and Microdochium nivale, other saprophyte, and several unidentified non-sporulating fungi were isolated at frequencies lower than 3% of the total. Fusarium crown rot and take-all were the most prevalent and distributed crown rot diseases present in wheat crops in southern Chile.

Identification and validation of reference genes for qRT-PCR studies of the obligate aphid pathogenic fungus Pandora neoaphidis during different developmental stages.

Science.gov (United States)

Zhang, Shutao; Chen, Chun; Xie, Tingna; Ye, Sudan

2017-01-01

The selection of stable reference genes is a critical step for the accurate quantification of gene expression. To identify and validate the reference genes in Pandora neoaphidis-an obligate aphid pathogenic fungus-the expression of 13classical candidate reference genes were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction(qPCR) at four developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae). Four statistical algorithms, including geNorm, NormFinder, BestKeeper and Delta Ct method were used to rank putative reference genes according to their expression stability and indicate the best reference gene or combination of reference genes for accurate normalization. The analysis of comprehensive ranking revealed that ACT1and 18Swas the most stably expressed genes throughout the developmental stages. To further validate the suitability of the reference genes identified in this study, the expression of cell division control protein 25 (CDC25) and Chitinase 1(CHI1) genes were used to further confirm the validated candidate reference genes. Our study presented the first systematic study of reference gene(s) selection for P. neoaphidis study and provided guidelines to obtain more accurate qPCR results for future developmental efforts.

Antifungal Activity of the Volatiles of High Potency Cannabis sativa L. Against Cryptococcus neoformans

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Amira S. Wanas

2016-03-01

Full Text Available The n-hexane extracted volatile fraction of high potency Cannabis sativa L (Cannabaceae . was assessed in vitro for antifungal, antibacterial and antileishmanial activities. The oil exhibited selective albeit modest, antifungal activity against Cryptococcus neoformans with an IC 50 value of 33.1 µg/mL. Biologically-guided fractionation of the volatile fraction resulted in the isolation of three major compounds (1-3 using various chromatographic techniques. The chemical structures of the isolated compounds were identified as α-humulene (1, b -caryophyllene (2 and caryophyllene oxide (3 using GC/FID, GC/MS, 1D- and 2D-NMR analyses, respectively. Compound 1 showed potent and selective antifungal activity against Cryptococcus neoformans with IC 50 and MIC values of 1.18 m g/mL and 5.0 m g/mL respectively. Whereas compound 2 showed weak activity (IC 50 19.4 µg/mL, while compound 3 was inactive against C. neoformans.

The role of strigolactones during plant interactions with the pathogenic fungus Fusarium oxysporum.

Science.gov (United States)

Foo, Eloise; Blake, Sara N; Fisher, Brendan J; Smith, Jason A; Reid, James B

2016-06-01

Strigolactones (SLs) do not influence spore germination or hyphal growth of Fusarium oxysporum. Mutant studies revealed no role for SLs but a role for ethylene signalling in defence against this pathogen in pea. Strigolactones (SLs) play important roles both inside the plant as a hormone and outside the plant as a rhizosphere signal in interactions with mycorrhizal fungi and parasitic weeds. What is less well understood is any potential role SLs may play in interactions with disease causing microbes such as pathogenic fungi. In this paper we investigate the influence of SLs on the hemibiotrophic pathogen Fusarium oxysporum f.sp. pisi both directly via their effects on fungal growth and inside the plant through the use of a mutant deficient in SL. Given that various stereoisomers of synthetic and naturally occuring SLs can display different biological activities, we used (+)-GR24, (-)-GR24 and the naturally occurring SL, (+)-strigol, as well as a racemic mixture of 5-deoxystrigol. As a positive control, we examined the influence of a plant mutant with altered ethylene signalling, ein2, on disease development. We found no evidence that SLs influence spore germination or hyphal growth of Fusarium oxysporum and that, while ethylene signalling influences pea susceptibility to this pathogen, SLs do not.

Malaria mosquitoes attracted by fatal fungus.

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Justin George

Full Text Available Insect-killing fungi such as Beauveria bassiana are being evaluated as possible active ingredients for use in novel biopesticides against mosquito vectors that transmit malaria. Fungal pathogens infect through contact and so applications of spores to surfaces such as walls, nets, or other resting sites provide possible routes to infect mosquitoes in and around domestic dwellings. However, some insects can detect and actively avoid fungal spores to reduce infection risk. If true for mosquitoes, such behavior could render the biopesticide approach ineffective. Here we find that the spores of B. bassiana are highly attractive to females of Anopheles stephensi, a major anopheline mosquito vector of human malaria in Asia. We further find that An. stephensi females are preferentially attracted to dead and dying caterpillars infected with B. bassiana, landing on them and subsequently becoming infected with the fungus. Females are also preferentially attracted to cloth sprayed with oil-formulated B. bassiana spores, with 95% of the attracted females becoming infected after a one-minute visit on the cloth. This is the first report of an insect being attracted to a lethal fungal pathogen. The exact mechanisms involved in this behavior remain unclear. Nonetheless, our results indicate that biopesticidal formulations comprising B. bassiana spores will be conducive to attraction and on-source visitation by malaria vectors.

Harbouring public good mutants within a pathogen population can increase both fitness and virulence.

Science.gov (United States)

Lindsay, Richard J; Kershaw, Michael J; Pawlowska, Bogna J; Talbot, Nicholas J; Gudelj, Ivana

2016-12-28

Existing theory, empirical, clinical and field research all predict that reducing the virulence of individuals within a pathogen population will reduce the overall virulence, rendering disease less severe. Here, we show that this seemingly successful disease management strategy can fail with devastating consequences for infected hosts. We deploy cooperation theory and a novel synthetic system involving the rice blast fungus Magnaporthe oryzae . In vivo infections of rice demonstrate that M. oryzae virulence is enhanced, quite paradoxically, when a public good mutant is present in a population of high-virulence pathogens. We reason that during infection, the fungus engages in multiple cooperative acts to exploit host resources. We establish a multi-trait cooperation model which suggests that the observed failure of the virulence reduction strategy is caused by the interference between different social traits. Multi-trait cooperative interactions are widespread, so we caution against the indiscriminant application of anti-virulence therapy as a disease-management strategy.

Function of VtPGIP in pathogenic fungus resistance of Vitis thunbergii

African Journals Online (AJOL)

In plants, polygalacturonase inhibitor proteins (PGIPs) are very important to inactivate polygalacturonases secreted by pathogens. Vitis thunbergii Sieb. et Zucc. polygalacturonase inhibitor proteins (VtPGIP) was first isolated from the wild grape Vitis thunbergii Sieb. et Zucc., which exhibits high resistance to disease. VtPGIP ...

A fungal pathogen of amphibians, Batrachochytrium dendrobatidis, attenuates in pathogenicity with in vitro passages.

Science.gov (United States)

Langhammer, Penny F; Lips, Karen R; Burrowes, Patricia A; Tunstall, Tate; Palmer, Crystal M; Collins, James P

2013-01-01

Laboratory investigations into the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), have accelerated recently, given the pathogen's role in causing the global decline and extinction of amphibians. Studies in which host animals were exposed to Bd have largely assumed that lab-maintained pathogen cultures retained the infective and pathogenic properties of wild isolates. Attenuated pathogenicity is common in artificially maintained cultures of other pathogenic fungi, but to date, it is unknown whether, and to what degree, Bd might change in culture. We compared zoospore production over time in two samples of a single Bd isolate having different passage histories: one maintained in artificial media for more than six years (JEL427-P39), and one recently thawed from cryopreserved stock (JEL427-P9). In a common garden experiment, we then exposed two different amphibian species, Eleutherodactylus coqui and Atelopus zeteki, to both cultures to test whether Bd attenuates in pathogenicity with in vitro passages. The culture with the shorter passage history, JEL427-P9, had significantly greater zoospore densities over time compared to JEL427-P39. This difference in zoospore production was associated with a difference in pathogenicity for a susceptible amphibian species, indicating that fecundity may be an important virulence factor for Bd. In the 130-day experiment, Atelopus zeteki frogs exposed to the JEL427-P9 culture experienced higher average infection intensity and 100% mortality, compared with 60% mortality for frogs exposed to JEL427-P39. This effect was not observed with Eleutherodactylus coqui, which was able to clear infection. We hypothesize that the differences in phenotypic performance observed with Atelopus zeteki are rooted in changes of the Bd genome. Future investigations enabled by this study will focus on the underlying mechanisms of Bd pathogenicity.

A fungal pathogen of amphibians, Batrachochytrium dendrobatidis, attenuates in pathogenicity with in vitro passages.

Directory of Open Access Journals (Sweden)

Penny F Langhammer

Full Text Available Laboratory investigations into the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, have accelerated recently, given the pathogen's role in causing the global decline and extinction of amphibians. Studies in which host animals were exposed to Bd have largely assumed that lab-maintained pathogen cultures retained the infective and pathogenic properties of wild isolates. Attenuated pathogenicity is common in artificially maintained cultures of other pathogenic fungi, but to date, it is unknown whether, and to what degree, Bd might change in culture. We compared zoospore production over time in two samples of a single Bd isolate having different passage histories: one maintained in artificial media for more than six years (JEL427-P39, and one recently thawed from cryopreserved stock (JEL427-P9. In a common garden experiment, we then exposed two different amphibian species, Eleutherodactylus coqui and Atelopus zeteki, to both cultures to test whether Bd attenuates in pathogenicity with in vitro passages. The culture with the shorter passage history, JEL427-P9, had significantly greater zoospore densities over time compared to JEL427-P39. This difference in zoospore production was associated with a difference in pathogenicity for a susceptible amphibian species, indicating that fecundity may be an important virulence factor for Bd. In the 130-day experiment, Atelopus zeteki frogs exposed to the JEL427-P9 culture experienced higher average infection intensity and 100% mortality, compared with 60% mortality for frogs exposed to JEL427-P39. This effect was not observed with Eleutherodactylus coqui, which was able to clear infection. We hypothesize that the differences in phenotypic performance observed with Atelopus zeteki are rooted in changes of the Bd genome. Future investigations enabled by this study will focus on the underlying mechanisms of Bd pathogenicity.

Fungus Causing White-Nose Syndrome in Bats Accumulates Genetic Variability in North America with No Sign of Recombination.

Science.gov (United States)

Trivedi, Jigar; Lachapelle, Josianne; Vanderwolf, Karen J; Misra, Vikram; Willis, Craig K R; Ratcliffe, John M; Ness, Rob W; Anderson, James B; Kohn, Linda M

2017-01-01

Emerging fungal diseases of wildlife are on the rise worldwide, and the white-nose syndrome (WNS) epidemic in North American bats is a catastrophic example. The causal agent of WNS is a single clone of the fungus Pseudogymnoascus destructans . Early evolutionary change in this clonal population has major implications for disease ecology and conservation. Accumulation of variation in the fungus through mutation, and shuffling of variation through recombination, could affect the virulence and transmissibility of the fungus and the durability of what appears to be resistance arising in some bat populations. Our genome-wide analysis shows that the clonal population of P. destructans has expanded in size from a single genotype, has begun to accumulate variation through mutation, and presents no evidence as yet of genetic exchange among individuals. IMPORTANCE Since its discovery in 2006, the emerging infectious disease known as white-nose syndrome has killed millions of bats in North America, making it one of the most devastating wildlife epidemics in recorded history. We demonstrate that there has been as yet only spontaneous mutation across the North American population of P. destructans , and we find no indication of recombination. Thus, selective forces, which might otherwise impact pathogenic virulence, have so far had essentially no genetic variation on which to act. Our study confirmed the time of origin for the first and, thus far, only introduction of P. destructans to North America. This system provides an unprecedented opportunity to follow the evolution of a host-pathogen interaction unfolding in real time.

A new F-actin structure in fungi: actin ring formation around the cell nucleus of Cryptococcus neoformans.

Science.gov (United States)

Kopecká, Marie; Kawamoto, Susumu; Yamaguchi, Masashi

2013-04-01

The F-actin cytoskeleton of Cryptococcus neoformans is known to comprise actin cables, cortical patches and cytokinetic ring. Here, we describe a new F-actin structure in fungi, a perinuclear F-actin collar ring around the cell nucleus, by fluorescent microscopic imaging of rhodamine phalloidin-stained F-actin. Perinuclear F-actin rings form in Cryptococcus neoformans treated with the microtubule inhibitor Nocodazole or with the drug solvent dimethyl sulfoxide (DMSO) or grown in yeast extract peptone dextrose (YEPD) medium, but they are absent in cells treated with Latrunculin A. Perinuclear F-actin rings may function as 'funicular cabin' for the cell nucleus, and actin cables as intracellular 'funicular' suspending nucleus in the central position in the cell and moving nucleus along the polarity axis along actin cables.

Major transcriptome reprogramming underlies floral mimicry induced by the rust fungus Puccinia monoica in Boechera stricta.

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Liliana M Cano

Full Text Available Pucciniamonoica is a spectacular plant parasitic rust fungus that triggers the formation of flower-like structures (pseudoflowers in its Brassicaceae host plant Boecherastricta. Pseudoflowers mimic in shape, color, nectar and scent co-occurring and unrelated flowers such as buttercups. They act to attract insects thereby aiding spore dispersal and sexual reproduction of the rust fungus. Although much ecological research has been performed on P. monoica-induced pseudoflowers, this system has yet to be investigated at the molecular or genomic level. To date, the molecular alterations underlying the development of pseudoflowers and the genes involved have not been described. To address this, we performed gene expression profiling to reveal 256 plant biological processes that are significantly altered in pseudoflowers. Among these biological processes, plant genes involved in cell fate specification, regulation of transcription, reproduction, floral organ development, anthocyanin (major floral pigments and terpenoid biosynthesis (major floral volatile compounds were down-regulated in pseudoflowers. In contrast, plant genes involved in shoot, cotyledon and leaf development, carbohydrate transport, wax biosynthesis, cutin transport and L-phenylalanine metabolism (pathway that results in phenylethanol and phenylacetaldehyde volatile production were up-regulated. These findings point to an extensive reprogramming of host genes by the rust pathogen to induce floral mimicry. We also highlight 31 differentially regulated plant genes that are enriched in the biological processes mentioned above, and are potentially involved in the formation of pseudoflowers. This work illustrates the complex perturbations induced by rust pathogens in their host plants, and provides a starting point for understanding the molecular mechanisms of pathogen-induced floral mimicry.

Growth under visible light increases conidia and mucilage production and tolerance to UV-B radiation in the plant pathogenic fungus Colletotrichum acutatum.

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de Menezes, Henrique D; Massola, Nelson S; Flint, Stephan D; Silva, Geraldo J; Bachmann, Luciano; Rangel, Drauzio E N; Braga, Gilberto U L

2015-01-01

Light conditions can influence fungal development. Some spectral wavebands can induce conidial production, whereas others can kill the conidia, reducing the population size and limiting dispersal. The plant pathogenic fungus Colletotrichum acutatum causes anthracnose in several crops. During the asexual stage on the host plant, Colletototrichum produces acervuli with abundant mucilage-embedded conidia. These conidia are responsible for fungal dispersal and host infection. This study examined the effect of visible light during C. acutatum growth on the production of conidia and mucilage and also on the UV tolerance of these conidia. Conidial tolerance to an environmentally realistic UV irradiance was determined both in conidia surrounded by mucilage on sporulating colonies and in conidial suspension. Exposures to visible light during fungal growth increased production of conidia and mucilage as well as conidial tolerance to UV. Colonies exposed to light produced 1.7 times more conidia than colonies grown in continuous darkness. The UV tolerances of conidia produced under light were at least two times higher than conidia produced in the dark. Conidia embedded in the mucilage on sporulating colonies were more tolerant of UV than conidia in suspension that were washed free of mucilage. Conidial tolerance to UV radiation varied among five selected isolates. © 2014 The American Society of Photobiology.

Antifouling and antibacterial polyketides from marine gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023.

Science.gov (United States)

Bao, Jie; Sun, Yu-Lin; Zhang, Xiao-Yong; Han, Zhuang; Gao, Hai-Chun; He, Fei; Qian, Pei-Yuan; Qi, Shu-Hua

2013-04-01

Two new polyketides, 6,8,5'6'-tetrahydroxy-3'-methylflavone (1) and paecilin C (2), together with six known analogs secalonic acid D (3), secalonic acid B (4) penicillixanthone A (5), emodin (6), citreorosein (7) and isorhodoptilometrin (8) were obtained from a broth of gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023. Compounds 1 and 6-8 had significant antifouling activity against Balanus amphitrite larvae settlement with EC50 values of 6.7, 6.1, 17.9 and 13.7 μg ml(-1), respectively, and 3-5 showed medium antibacterial activity against four tested bacterial strains. This was the first report of antibacterial activity of 3-5 against marine bacteria and antifouling activity of 6-8 against marine biofouling organism's larvae. The results indicated that gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023 strain could produce antifouling and antibacterial compounds that might aid the host gorgonian coral in protection against marine pathogen bacteria, biofouling organisms and other intruders.

Identifying pathogenicity genes in the rubber tree anthracnose fungus Colletotrichum gloeosporioides through random insertional mutagenesis.

Science.gov (United States)

Cai, Zhiying; Li, Guohua; Lin, Chunhua; Shi, Tao; Zhai, Ligang; Chen, Yipeng; Huang, Guixiu

2013-07-19

To gain more insight into the molecular mechanisms of Colletotrichum gloeosporioides pathogenesis, Agrobacterium tumefaciens-mediated transformation (ATMT) was used to identify mutants of C. gloeosporioides impaired in pathogenicity. An ATMT library of 4128 C. gloeosporioides transformants was generated. Transformants were screened for defects in pathogenicity with a detached copper brown leaf assay. 32 mutants showing reproducible pathogenicity defects were obtained. Southern blot analysis showed 60.4% of the transformants had single-site T-DNA integrations. 16 Genomic sequences flanking T-DNA were recovered from mutants by thermal asymmetric interlaced PCR, and were used to isolate the tagged genes from the genome sequence of wild-type C. gloeosporioides by Basic Local Alignment Search Tool searches against the local genome database of the wild-type C. gloeosporioides. One potential pathogenicity genes encoded calcium-translocating P-type ATPase. Six potential pathogenicity genes had no known homologs in filamentous fungi and were likely to be novel fungal virulence factors. Two putative genes encoded Glycosyltransferase family 28 domain-containing protein and Mov34/MPN/PAD-1 family protein, respectively. Five potential pathogenicity genes had putative function matched with putative protein of other Colletotrichum species. Two known C. gloeosporioides pathogenicity genes were also identified, the encoding Glomerella cingulata hard-surface induced protein and C. gloeosporioides regulatory subunit of protein kinase A gene involved in cAMP-dependent PKA signal transduction pathway. Copyright © 2013 Elsevier GmbH. All rights reserved.

β-Carbonic Anhydrases Play a Role in Fruiting Body Development and Ascospore Germination in the Filamentous Fungus Sordaria macrospora

Science.gov (United States)

Elleuche, Skander; Pöggeler, Stefanie

2009-01-01

Carbon dioxide (CO2) is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO3 −) reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs). These enzymes are grouped by their distinct structural features into α-, β-, γ-, δ- and ζ-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of β-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria) encoding β-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Δcas1, Δcas2, and Δcas3) as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Δcas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Δcas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO2 levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and non-specific functions. PMID:19365544

Beta-carbonic anhydrases play a role in fruiting body development and ascospore germination in the filamentous fungus Sordaria macrospora.

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Skander Elleuche

Full Text Available Carbon dioxide (CO(2 is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO(3 (- reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs. These enzymes are grouped by their distinct structural features into alpha-, beta-, gamma-, delta- and zeta-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of beta-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria encoding beta-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Deltacas1, Deltacas2, and Deltacas3 as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO(2 levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of

Beta-carbonic anhydrases play a role in fruiting body development and ascospore germination in the filamentous fungus Sordaria macrospora.

Science.gov (United States)

Elleuche, Skander; Pöggeler, Stefanie

2009-01-01

Carbon dioxide (CO(2)) is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO(3) (-)) reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs). These enzymes are grouped by their distinct structural features into alpha-, beta-, gamma-, delta- and zeta-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of beta-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria) encoding beta-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Deltacas1, Deltacas2, and Deltacas3) as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO(2) levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and

Matrix metalloproteinases operate redundantly in Arabidopsis immunity against necrotrophic and biotrophic fungal pathogens.

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Puyan Zhao

Full Text Available Matrix metalloproteinases (MMPs are evolutionarily conserved and multifunctional effector molecules playing pivotal roles in development and homeostasis. In this study we explored the involvement of the five Arabidopsis thaliana At-MMPs in plant defence against microbial pathogens. Expression of At2-MMP was most responsive to inoculation with fungi and a bacterial pathogen followed by At3-MMP and At5-MMP, while At1-MMP and At4-MMP were non-responsive to these biotic stresses. Loss-of-function mutants for all tested At-MMPs displayed increased susceptibility to the necrotrophic fungus Botrytis cinerea and double mutant at2,3-mmp and triple mutant at2,3,5-mmp plants developed even stronger symptoms. Consistent with this, transgenic Arabidopsis plants that expressed At2-MMP constitutively under the Cauliflower mosaic virus 35S promoter showed enhanced resistance to the necrotrophic pathogen. Similarly, resistance to the biotrophic Arabidopsis powdery mildew fungus Golovinomyces orontii was also compromised particularly in the at2,3-mmp / at2,3,5-mmp multiplex mutants, and increased in At2-MMP overexpressor plants. The degree of disease resistance of at-mmp mutants and At2-MMP overexpressor plants also correlated positively with the degree of MAMP-triggered callose deposition in response to the bacterial flagellin peptide flg22, suggesting that matrix metalloproteinases contribute to pattern-triggered immunity (PTI in interactions of Arabidopsis with necrotrophic and biotrophic pathogens.

Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S. dioica

NARCIS (Netherlands)

Van Putten, W.F.; Biere, A.; Van Damme, J.M.M.

2005-01-01

We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus

Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S-dioica

NARCIS (Netherlands)

Van Putten, WF; Biere, A; Van Damme, JMM

We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus

The variety mixture strategy assessed in a G × G experiment with rice and the blast fungus Magnaporthe oryzae.

Science.gov (United States)

Gallet, Romain; Bonnot, François; Milazzo, Joëlle; Tertois, Christophe; Adreit, Henri; Ravigné, Virginie; Tharreau, Didier; Fournier, Elisabeth

2013-01-01

Frequent and devastating epidemics of parasites are one of the major issues encountered by modern agriculture. To manage the impact of pathogens, resistant plant varieties have been selected. However, resistances are overcome by parasites requiring the use of pesticides and causing new economical and food safety issues. A promising strategy to maintain the epidemic at a low level and hamper pathogen's adaptation to varietal resistance is the use of mixtures of varieties such that the mix will form a heterogeneous environment for the parasite. A way to find the good combination of varieties that will actually constitute a heterogeneous environment for pathogens is to look for genotype × genotype (G × G) interactions between pathogens and plant varieties. A pattern in which pathogens have a high fitness on one variety and a poor fitness on other varieties guarantees the efficiency of the mixture strategy. In the present article, we inoculated 18 different genotypes of the fungus Magnaporthe oryzae on three rice plant varieties showing different levels of partial resistance in order to find a variety combination compatible with the requirements of the variety mixture strategy, i.e., showing appropriate G × G interactions. We estimated the success of each plant-fungus interaction by measuring fungal fitness and three fungal life history traits: infection success, within-host growth, sporulation capacity. Our results show the existence of G × G interactions between the two varieties Ariete and CO39 on all measured traits and fungal fitness. We also observed that these varieties have different resistance mechanisms; Ariete is good at controlling infection success of the parasite but is not able to control its growth when inside the leaf, while CO39 shows the opposite pattern. We also found that Maratelli's resistance has been eroded. Finally, correlation analyses demonstrated that not all infectious traits are positively correlated.

Future potential distribution of the emerging amphibian chytrid fungus under anthropogenic climate change.

Science.gov (United States)

Rödder, Dennis; Kielgast, Jos; Lötters, Stefan

2010-11-01

Anthropogenic climate change poses a major threat to global biodiversity with a potential to alter biological interactions at all spatial scales. Amphibians are the most threatened vertebrates and have been subject to increasing conservation attention over the past decade. A particular concern is the pandemic emergence of the parasitic chytrid fungus Batrachochytrium dendrobatidis, which has been identified as the cause of extremely rapid large-scale declines and species extinctions. Experimental and observational studies have demonstrated that the host-pathogen system is strongly influenced by climatic parameters and thereby potentially affected by climate change. Herein we project a species distribution model of the pathogen onto future climatic scenarios generated by the IPCC to examine their potential implications on the pandemic. Results suggest that predicted anthropogenic climate change may reduce the geographic range of B. dendrobatidis and its potential influence on amphibian biodiversity.

Three New Indole Diterpenoids from the Sea-Anemone-Derived Fungus Penicillium sp. AS-79.

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Hu, Xue-Yi; Meng, Ling-Hong; Li, Xin; Yang, Sui-Qun; Li, Xiao-Ming; Wang, Bin-Gui

2017-05-12

Three new indolediterpenoids, namely, 22-hydroxylshearinine F ( 1 ), 6-hydroxylpaspalinine ( 2 ), and 7- O -acetylemindole SB ( 3 ), along with eight related known analogs ( 4 - 11 ), were isolated from the sea-anemone-derived fungus Penicillium sp. AS-79. The structures and relative configurations of these compounds were determined by a detailed interpretation of the spectroscopic data, and their absolute configurations were determined by ECD calculations ( 1 and 2 ) and single-crystal X-ray diffraction ( 3 ). Some of these compounds exhibited prominent activity against aquatic and human pathogenic microbes.

Comparative genomics of Cryptococcus neoformans var. grubii associated with meningitis in HIV infected and uninfected patients in Vietnam.

Science.gov (United States)

Day, Jeremy N; Qihui, Seet; Thanh, Lam Tuan; Trieu, Phan Hai; Van, Anh Duong; Thu, Nha Hoang; Chau, Tran Thi Hong; Lan, Nguyen P H; Chau, Nguyen Van Vinh; Ashton, Philip M; Thwaites, Guy E; Boni, Maciej F; Wolbers, Marcel; Nagarajan, Niranjan; Tan, Patrick B O; Baker, Stephen

2017-06-01

and various drug transporters. Our work outlines the complexity of genomic pathogenicity in cryptococcal infections and identifies a number of gene candidates that may aid the disaggregation of the pathways associated with the pathogenesis of Cryptococcus neoformans var. grubii.

Does methyl salicylate, a component of herbivore-induced plant odour, promote sporulation of the mite-pathogenic fungus Neozygites tanajoae?

NARCIS (Netherlands)

Hountondji, F.C.C.; Hanna, R.; Sabelis, M.W.

2006-01-01

Abstract : Blends of volatile chemicals emanating from cassava leaves infested by the cassava green mite were found to promote conidiation of Neozygites tanajoae, an entomopathogenic fungus specific to this mite. Methyl salicylate (MeSA) is one compound frequently present in blends of

Fusion: a tale of recombination in an asexual fungus: The role of nuclear dynamics and hyphal fusion in horizontal chromosome transfer in Fusarium oxysporum

NARCIS (Netherlands)

Shahi, S.

2016-01-01

Recent studies have shown that not only meiotic recombination is responsible for the fast evolution of fungal pathogens. In the asexual fungus F. oxysporum (Fo) the "fast" evolving part of the genome is organized into small chromosomes and one such chromosome houses all effector genes and is

Crystal Structures and Small-angle X-ray Scattering Analysis of UDP-galactopyranose Mutase from the Pathogenic Fungus Aspergillus fumigatus

Energy Technology Data Exchange (ETDEWEB)

Dhatwalia, Richa; Singh, Harkewal; Oppenheimer, Michelle; Karr, Dale B.; Nix, Jay C.; Sobrado, Pablo; Tanner, John J. (LBNL); (Missouri); (VPI)

2015-10-15

UDP-galactopyranose mutase (UGM) is a flavoenzyme that catalyzes the conversion of UDP-galactopyranose to UDP-galactofuranose, which is a central reaction in galactofuranose biosynthesis. Galactofuranose has never been found in humans but is an essential building block of the cell wall and extracellular matrix of many bacteria, fungi, and protozoa. The importance of UGM for the viability of many pathogens and its absence in humans make UGM a potential drug target. Here we report the first crystal structures and small-angle x-ray scattering data for UGM from the fungus Aspergillus fumigatus, the causative agent of aspergillosis. The structures reveal that Aspergillus UGM has several extra secondary and tertiary structural elements that are not found in bacterial UGMs yet are important for substrate recognition and oligomerization. Small-angle x-ray scattering data show that Aspergillus UGM forms a tetramer in solution, which is unprecedented for UGMs. The binding of UDP or the substrate induces profound conformational changes in the enzyme. Two loops on opposite sides of the active site move toward each other by over 10 {angstrom} to cover the substrate and create a closed active site. The degree of substrate-induced conformational change exceeds that of bacterial UGMs and is a direct consequence of the unique quaternary structure of Aspergillus UGM. Galactopyranose binds at the re face of the FAD isoalloxazine with the anomeric carbon atom poised for nucleophilic attack by the FAD N5 atom. The structural data provide new insight into substrate recognition and the catalytic mechanism and thus will aid inhibitor design.

Analysis of whitefly transcriptional responses to Beauveria bassiana infection reveals new insights into insect-fungus interactions.

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Xia, Jun; Zhang, Chang-Rong; Zhang, Shan; Li, Fang-Fang; Feng, Ming-Guang; Wang, Xiao-Wei; Liu, Shu-Sheng

2013-01-01

The fungal pathogen, Beauveria bassiana, is an efficient biocontrol agent against a variety of agricultural pests. A thorough understanding of the basic principles of insect-fungus interactions may enable the genetic modification of Beauveria bassiana to enhance its virulence. However, the molecular mechanism of insect response to Beauveria bassiana infection is poorly understood, let alone the identification of fungal virulent factors involved in pathogenesis. Here, next generation sequencing technology was applied to examine the expression of whitefly (Bemisia tabaci) genes in response to the infection of Beauveria bassiana. Results showed that, compared to control, 654 and 1,681genes were differentially expressed at 48 hours and 72 hours post-infected whiteflies, respectively. Functional and enrichment analyses indicated that the DNA damage stimulus response and drug metabolism were important anti-fungi strategies of the whitefly. Mitogen-activated protein kinase (MAPK) pathway was also likely involved in the whitefly defense responses. Furthermore, the notable suppression of general metabolism and ion transport genes observed in 72 hours post-infected B. tabaci might be manipulated by fungal secreted effectors. By mapping the sequencing tags to B. bassiana genome, we also identified a number of differentially expressed fungal genes between the early and late infection stages. These genes are generally associated with fungal cell wall synthesis and energy metabolism. The expression of fungal cell wall protein genes might play an important role in fungal pathogenesis and the dramatically up-regulated enzymes of carbon metabolism indicate the increasing usage of energy during the fungal infection. To our knowledge, this is the first report on the molecular mechanism of fungus-whitefly interactions. Our results provide a road map for future investigations on insect-pathogen interactions and genetically modifying the fungus to enhance its efficiency in whitefly

The variety mixture strategy assessed in a GXG experiment with rice and the blast fungus Magnaporthe oryzae

Directory of Open Access Journals (Sweden)

Romain eGallet

2014-01-01

Full Text Available Frequent and devastating epidemics of parasites are one of the major issues encountered by modern agriculture. To manage the impact of pathogens, resistant plant varieties have been selected. However, resistances are overcome by parasites requiring the use of pesticides and causing new economical and food safety issues. A promising strategy to maintain the epidemic at a low level and hamper pathogen’s adaptation to varietal resistance is the use of mixtures of varieties such that the mix will form a heterogeneous environment for the parasite. A way to find the good combination of varieties that will actually constitute a heterogeneous environment for pathogens is to look for genotype x genotype (GxG interactions between pathogens and plant varieties. A pattern in which pathogens have a high fitness on one variety and a poor fitness on other varieties guarantees the efficiency of the mixture strategy.In the present article, we inoculated 18 different genotypes of the fungus Magnaporthe oryzae on three rice plant varieties showing different levels of partial resistance in order to find a variety combination compatible with the requirements of the variety mixture strategy, i.e. showing appropriate GxG interactions. We estimated the success of each plant-fungus interaction by measuring fungal fitness and three fungal life history traits: infection success, within-host growth, sporulation capacity. Our results show the existence of GxG interactions between the two varieties Ariete and CO39 on all measured traits and fungal fitness. We also observed that these varieties have different resistance mechanisms; Ariete is good at controlling infection success of the parasite but is not able to control its growth when inside the leaf, while CO39 show the opposite pattern. We also found that Maratelli’s resistance has been eroded. Finally, correlation analyses demonstrated that not all infectious traits are positively correlated.

Trichoderma-plant-pathogen interactions: advances in genetics of biological control.

Science.gov (United States)

Mukherjee, Mala; Mukherjee, Prasun K; Horwitz, Benjamin A; Zachow, Christin; Berg, Gabriele; Zeilinger, Susanne

2012-12-01

Trichoderma spp. are widely used in agriculture as biofungicides. Induction of plant defense and mycoparasitism (killing of one fungus by another) are considered to be the most important mechanisms of Trichoderma-mediated biological control. Understanding these mechanisms at the molecular level would help in developing strains with superior biocontrol properties. In this article, we review our current understanding of the genetics of interactions of Trichoderma with plants and plant pathogens.

Microsatellite primers for fungus-growing ants

DEFF Research Database (Denmark)

Villesen, Palle; Gertsch, P J; Boomsma, JJ

2002-01-01

We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

Microsatellite Primers for Fungus-Growing Ants

DEFF Research Database (Denmark)

Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

2002-01-01

We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

Дрожжи в борьбе с возбудителем заболевания серая гниль Botrytis cinerea

OpenAIRE

Храбрых, О.; Барайщук, Г.; Kollar, Andreas; Jelkmann, Wilhelm

2007-01-01

Серая гниль наиболее распространенное и вредоносное заболевание, вызываемое грибом Botrytis cinerea.The ability of yeasts to inhibit the growth and development of the fungus Botrytis cinerea causes grey mould was detected in vitro during co-culturing the micro organisms on agar plates and in liquid conditions. The radial growth of the pathogen was inhibited in the presence of many tested yeasts on agar plates. In liquid, Aureobasidium pullulans, Cryptococcus laurentii, Candida sake, Hansenias...

Antibacterial α-pyrone derivatives from a mangrove-derived fungus Stemphylium sp. 33231 from the South China Sea.

Science.gov (United States)

Zhou, Xue-Ming; Zheng, Cai-Juan; Song, Xiao-Ping; Han, Chang-Ri; Chen, Wen-Hao; Chen, Guang-Ying

2014-05-01

Two new α-pyrone derivatives, infectopyrones A (1) and B (2), were obtained from the EtOAc extract of the endophytic fungus Stemphylium sp. 33231 isolated from the mangrove Brguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1 and 2 were evaluated for their antibacterial activities, and they had a broad spectrum of antibacterial activity against five terrestrial pathogenic bacteria.

One fungus, one name promotes progressive plant pathology.

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Wingfield, Michael J; De Beer, Z Wilhelm; Slippers, Bernard; Wingfield, Brenda D; Groenewald, Johannes Z; Lombard, Lorenzo; Crous, Pedro W

2012-08-01

The robust and reliable identification of fungi underpins virtually every element of plant pathology, from disease diagnosis to studies of biology, management/control, quarantine and, even more recently, comparative genomics. Most plant diseases are caused by fungi, typically pleomorphic organisms, for which the taxonomy and, in particular, a dual nomenclature system have frustrated and confused practitioners of plant pathology. The emergence of DNA sequencing has revealed cryptic taxa and revolutionized our understanding of relationships in the fungi. The impacts on plant pathology at every level are already immense and will continue to grow rapidly as new DNA sequencing technologies continue to emerge. DNA sequence comparisons, used to resolve a dual nomenclature problem for the first time only 19 years ago, have made it possible to approach a natural classification for the fungi and to abandon the confusing dual nomenclature system. The journey to a one fungus, one name taxonomic reality has been long and arduous, but its time has come. This will inevitably have a positive impact on plant pathology, plant pathologists and future students of this hugely important discipline on which the world depends for food security and plant health in general. This contemporary review highlights the problems of a dual nomenclature, especially its impact on plant pathogenic fungi, and charts the road to a one fungus, one name system that is rapidly drawing near. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

Dutch elm disease pathogen transmission by the banded elm bark beetle Scolytus schevyrewi

Science.gov (United States)

W. R. Jacobi; R. D. Koski; J. F. Negron

2013-01-01

Dutch Elm Disease (DED) is a vascular wilt disease of Ulmus species (elms) incited in North America primarily by the exotic fungus Ophiostoma novo-ulmi. The pathogen is transmitted via root grafts and elm bark beetle vectors, including the native North American elm bark beetle, Hylurgopinus rufipes and the exotic smaller European elm bark beetle, Scolytus multistriatus...

The 14-3-3 homolog, ArtA, regulates development and secondary metabolism in the opportunistic plant pathogen Aspergillus flavus

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The opportunistic plant pathogenic fungus Aspergillus flavus produces carcinogenic mycotoxins denominated aflatoxins (AFs). Aflatoxin contamination of agriculturally important crops such as maize, peanut, sorghum and tree nuts is responsible for serious adverse health and economic impacts worldwide....

A nitrogen response pathway regulates virulence in plant pathogenic fungi: role of TOR and the bZIP protein MeaB.

Science.gov (United States)

López-Berges, Manuel S; Rispail, Nicolas; Prados-Rosales, Rafael C; Di Pietro, Antonio

2010-12-01

Virulence in plant pathogenic fungi is controlled through a variety of cellular pathways in response to the host environment. Nitrogen limitation has been proposed to act as a key signal to trigger the in planta expression of virulence genes. Moreover, a conserved Pathogenicity mitogen activated protein kinase (MAPK) cascade is strictly required for plant infection in a wide range of pathogens. We investigated the relationship between nitrogen signaling and the Pathogenicity MAPK cascade in controlling infectious growth of the vascular wilt fungus Fusarium oxysporum. Several MAPK-activated virulence functions such as invasive growth, vegetative hyphal fusion and host adhesion were strongly repressed in the presence of the preferred nitrogen source ammonium. Repression of these functions by ammonium was abolished by L-Methionine sulfoximine (MSX) or rapamycin, two specific inhibitors of Gln synthetase and the protein kinase TOR (Target Of Rapamycin), respectively, and was dependent on the bZIP protein MeaB. Supplying tomato plants with ammonium rather than nitrate resulted in a significant delay of vascular wilt symptoms caused by the F. oxysporum wild type strain, but not by the ΔmeaB mutant. Ammonium also repressed invasive growth in two other pathogens, the rice blast fungus Magnaporthe oryzae and the wheat head blight pathogen Fusarium graminearum. Our results suggest the presence of a conserved nitrogen-responsive pathway that operates via TOR and MeaB to control infectious growth in plant pathogenic fungi.

Sodium chloride inhibits the growth and infective capacity of the amphibian chytrid fungus and increases host survival rates.

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Michelle Pirrie Stockwell

Full Text Available The amphibian chytrid fungus Batrachochytrium dendrobatidis is a recently emerged pathogen that causes the infectious disease chytridiomycosis and has been implicated as a contributing factor in the global amphibian decline. Since its discovery, research has been focused on developing various methods of mitigating the impact of chytridiomycosis on amphibian hosts but little attention has been given to the role of antifungal agents that could be added to the host's environment. Sodium chloride is a known antifungal agent used routinely in the aquaculture industry and this study investigates its potential for use as a disease management tool in amphibian conservation. The effect of 0-5 ppt NaCl on the growth, motility and survival of the chytrid fungus when grown in culture media and its effect on the growth, infection load and survivorship of infected Peron's tree frogs (Litoria peronii in captivity, was investigated. The results reveal that these concentrations do not negatively affect the survival of the host or the pathogen. However, concentrations greater than 3 ppt significantly reduced the growth and motility of the chytrid fungus compared to 0 ppt. Concentrations of 1-4 ppt NaCl were also associated with significantly lower host infection loads while infected hosts exposed to 3 and 4 ppt NaCl were found to have significantly higher survival rates. These results support the potential for NaCl to be used as an environmentally distributed antifungal agent for the prevention of chytridiomycosis in susceptible amphibian hosts. However, further research is required to identify any negative effects of salt exposure on both target and non-target organisms prior to implementation.

Rapid direct identification of Cryptococcus neoformans from pigeon droppings by nested PCR using CNLAC1 gene.

Science.gov (United States)

Chae, H S; Park, G N; Kim, S H; Jo, H J; Kim, J T; Jeoung, H Y; An, D J; Kim, N H; Shin, B W; Kang, Y I; Chang, K S

2012-08-01

Isolation and identification of Cryptococcus neoformans and pathogenic yeast-like fungi from pigeon droppings has been taken for a long time and requires various nutrients for its growth. In this study, we attempted to establish a rapid direct identification method of Cr. neoformans from pigeon dropping samples by nested-PCR using internal transcribed spacer (ITS) CAP64 and CNLAC1 genes, polysaccharide capsule gene and laccase-associated gene to produce melanin pigment, respectively, which are common genes of yeasts. The ITS and CAP64 genes were amplified in all pathogenic yeasts, but CNLAC1 was amplified only in Cr. neoformans. The ITS gene was useful for yeast genotyping depending on nucleotide sequence. Homology of CAP64 genes among the yeasts were very high. The specificity of PCR using CNLAC1 was demonstrated in Cr. neoformans environmental strains but not in other yeast-like fungi. The CNLAC1 gene was detected in 5 serotypes of Cr. neoformans. The nested-PCR amplified up to 10(-11) μg of the genomic DNA and showed high sensitivity. All pigeon droppings among 31 Cr. neoformans-positive samples were positive and all pigeon droppings among 348 Cr. neoformans-negative samples were negative by the direct nested-PCR. In addition, after primary enrichment of pigeon droppings in Sabouraud dextrose broth, all Cr. neoformans-negative samples were negative by the nested-PCR, which showed high specificity. The nested-PCR showed high sensitivity without culture of pigeon droppings. Nested-PCR using CNLAC1 provides a rapid and reliable molecular diagnostic method to overcome weak points such as long culture time of many conventional methods.

Identification and validation of reference genes for qRT-PCR studies of the obligate aphid pathogenic fungus Pandora neoaphidis during different developmental stages.

Directory of Open Access Journals (Sweden)

Shutao Zhang

Full Text Available The selection of stable reference genes is a critical step for the accurate quantification of gene expression. To identify and validate the reference genes in Pandora neoaphidis-an obligate aphid pathogenic fungus-the expression of 13classical candidate reference genes were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction(qPCR at four developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae. Four statistical algorithms, including geNorm, NormFinder, BestKeeper and Delta Ct method were used to rank putative reference genes according to their expression stability and indicate the best reference gene or combination of reference genes for accurate normalization. The analysis of comprehensive ranking revealed that ACT1and 18Swas the most stably expressed genes throughout the developmental stages. To further validate the suitability of the reference genes identified in this study, the expression of cell division control protein 25 (CDC25 and Chitinase 1(CHI1 genes were used to further confirm the validated candidate reference genes. Our study presented the first systematic study of reference gene(s selection for P. neoaphidis study and provided guidelines to obtain more accurate qPCR results for future developmental efforts.

Health monitoring of plants by their emitted volatiles: A temporary increase in the concentration of nethyl salicylate after pathogen inoculation of tomato plants at greenhouse scale

NARCIS (Netherlands)

Jansen, R.M.C.; Hofstee, J.W.; Verstappen, F.W.A.; Bouwmeester, H.J.; Posthumus, M.A.; Henten, van E.J.

2011-01-01

This paper describes a method to alert growers of the presence of a pathogen infection in their greenhouse based on the detection of pathogen-induced emissions of volatile organic compounds (VOCs) from plants. Greenhouse-grown plants were inoculated with spores of a fungus to learn more about this

Identification of Immunity-Related Genes in Dialeurodes citri against Entomopathogenic Fungus Lecanicillium attenuatum by RNA-Seq Analysis.

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Shijiang Yu

Full Text Available Dialeurodes citri is a major pest in citrus producing areas, and large-scale outbreaks have occurred increasingly often in recent years. Lecanicillium attenuatum is an important entomopathogenic fungus that can parasitize and kill D. citri. We separated the fungus from corpses of D. citri larvae. However, the sound immune defense system of pests makes infection by an entomopathogenic fungus difficult. Here we used RNA sequencing technology (RNA-Seq to build a transcriptome database for D. citri and performed digital gene expression profiling to screen genes that act in the immune defense of D. citri larvae infected with a pathogenic fungus. De novo assembly generated 84,733 unigenes with mean length of 772 nt. All unigenes were searched against GO, Nr, Swiss-Prot, COG, and KEGG databases and a total of 28,190 (33.3% unigenes were annotated. We identified 129 immunity-related unigenes in transcriptome database that were related to pattern recognition receptors, information transduction factors and response factors. From the digital gene expression profile, we identified 441 unigenes that were differentially expressed in D. citri infected with L. attenuatum. Through calculated Log2Ratio values, we identified genes for which fold changes in expression were obvious, including cuticle protein, vitellogenin, cathepsin, prophenoloxidase, clip-domain serine protease, lysozyme, and others. Subsequent quantitative real-time polymerase chain reaction analysis verified the results. The identified genes may serve as target genes for microbial control of D. citri.

Identification of Immunity-Related Genes in Dialeurodes citri against Entomopathogenic Fungus Lecanicillium attenuatum by RNA-Seq Analysis.

Science.gov (United States)

Yu, Shijiang; Ding, Lili; Luo, Ren; Li, Xiaojiao; Yang, Juan; Liu, Haoqiang; Cong, Lin; Ran, Chun

2016-01-01

Dialeurodes citri is a major pest in citrus producing areas, and large-scale outbreaks have occurred increasingly often in recent years. Lecanicillium attenuatum is an important entomopathogenic fungus that can parasitize and kill D. citri. We separated the fungus from corpses of D. citri larvae. However, the sound immune defense system of pests makes infection by an entomopathogenic fungus difficult. Here we used RNA sequencing technology (RNA-Seq) to build a transcriptome database for D. citri and performed digital gene expression profiling to screen genes that act in the immune defense of D. citri larvae infected with a pathogenic fungus. De novo assembly generated 84,733 unigenes with mean length of 772 nt. All unigenes were searched against GO, Nr, Swiss-Prot, COG, and KEGG databases and a total of 28,190 (33.3%) unigenes were annotated. We identified 129 immunity-related unigenes in transcriptome database that were related to pattern recognition receptors, information transduction factors and response factors. From the digital gene expression profile, we identified 441 unigenes that were differentially expressed in D. citri infected with L. attenuatum. Through calculated Log2Ratio values, we identified genes for which fold changes in expression were obvious, including cuticle protein, vitellogenin, cathepsin, prophenoloxidase, clip-domain serine protease, lysozyme, and others. Subsequent quantitative real-time polymerase chain reaction analysis verified the results. The identified genes may serve as target genes for microbial control of D. citri.

SEC14 is a specific requirement for secretion of phospholipase B1 and pathogenicity of Cryptococcus neoformans

Science.gov (United States)

Chayakulkeeree, Methee; Johnston, Simon Andrew; Oei, Johanes Bijosono; Lev, Sophie; Williamson, Peter Richard; Wilson, Christabel Frewen; Zuo, Xiaoming; Leal, Ana Lusia; Vainstein, Marilene Henning; Meyer, Wieland; Sorrell, Tania Christine; May, Robin Charles; Djordjevic, Julianne Teresa

2011-01-01

Summary Secreted phospholipase B1 (CnPlb1) is essential for dissemination of Cryptococcus neoformans to the central nervous system (CNS) yet essential components of its secretion machinery remain to be elucidated. Using gene deletion analysis we demonstrate that CnPlb1 secretion is dependent on the CnSEC14 product, CnSec14-1p. CnSec14-1p is a homologue of the phosphatidylinositol transfer protein (PITP) ScSec14p, which is essential for secretion and viability in Saccharomyces cerevisiae. In contrast to CnPlb1, neither laccase 1 (Lac1)-induced melanization within the cell wall nor capsule induction were negatively impacted in CnSEC14-1 deletion mutants (CnΔsec14-1 and CnΔsec14-1CnΔsfh5). Similar to the CnPLB1 deletion mutant (CnΔplb1), CnΔsec14-1 was hypo-virulent in mice and did not disseminate to the CNS by day 14 post infection. Furthermore, macrophage expulsion of live CnΔsec14-1 and CnΔplb1 (vomocytosis) was reduced. Individual deletion of CnSEC14-2, a closely-related CnSEC14-1 homologue, and CnSFH5, a distantly-related SEC fourteen-like homologue, did not abrogate CnPlb1 secretion or virulence. However, reconstitution of CnΔsec14-1 with CnSEC14-1 or CnSEC14-2 restored both phenotypes, consistent with functional genetic redundancy. We conclude that CnPlb1 secretion is SEC14-dependent and that C. neoformans preferentially exports virulence determinants to the cell periphery via distinct pathways. We also demonstrate that CnPlb1 secretion is essential for vomocytosis. PMID:21453402

Whole-genome sequence of the orchid anthracnose pathogen Colletotrichum orchidophilum.

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Baroncelli, Riccardo; Sukno, Serenella; Sarrocco, Sabrina; Cafà, Giovanni; Le Floch, Gaetan; Thon, Michael R

2018-04-12

Colletotrichum orchidophilum is a plant pathogenic fungus infecting a wide range of plant species belonging to the family Orchidaceae. Besides its economic impact, C. orchidophilum has been used in recent years in evolutionary studies as it represents the closest related species to the C. acutatum species complex. Here we present the first draft whole-genome sequence of C. orchidophilum IMI 309357, providing a resource for future research on anthracnose of Orchidaceae and other hosts.

Corruption of host seven-transmembrane proteins by pathogenic microbes: a common theme in animals and plants?

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Panstruga, Ralph; Schulze-Lefert, Paul

2003-04-01

Human diseases like AIDS, malaria, and pneumonia are caused by pathogens that corrupt host chemokine G-protein coupled receptors for molecular docking. Comparatively, little is known about plant host factors that are required for pathogenesis and that may serve as receptors for the entry of pathogenic microbes. Here, we review potential analogies between human chemokine receptors and the plant seven-transmembrane MLO protein, a candidate serving a dual role as docking molecule and defence modulator for the phytopathogenic powdery mildew fungus.

The efficacy of Carica papaya leaf extract on some bacterial and a fungal strain by well diffusion method

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C. Baskaran

2012-10-01

Full Text Available Objective: To investigate the antimicrobial activity and phytochemical screening Ethanol, methanol, Ethyl acetate, acetone, chloroform, Petroleum ether, hexane, hot water, and extracts of Carica papaya. Methods: The aim of the present study was to evaluate the qualitative analysis of phytochemicals and antimicrobial activity of various solvent extracts of Carica papaya. The antimicrobial activities of different solvent extracts of Carica papaya were tested against the Gram-positive and Gram-negative bacterial strains and fungus by observing the zone of inhibition. The Gram-positive bacteria used in the test were Staphylococcus aureus, Bacillus cereus and Micrococcus luteus, and the Gram-negative bacteria were Escherichia coli, and Klebsiella pneumoniae, fungus like Aspergillus niger, Aspergillus flavus, Candida albicans, Candida tropicalis, Cryptococcus neoformans, and Candida kefyr. Results: It was observed that ethanol, methanol, ethyl acetate, aceton, chloroform, petroleum ether, hexane and aquas extracts showed activity against bacteria and fungus. The chloroform extract of Carica papaya showed more activity against Micrococcus luteus, zone of diameter 15.17暲0.29mm and acetone extract of Carica papaya showed more activity against Candida albicans, zone of diameter 11.23暲0.25mm compared to other solvent extracts. Conclusions: In this study chloroform extract in bacteria and acetone extract in fungus showed a varying degree of inhibition to the growth of tested organism, than Ethanol, methanol, Ethyl acetate, Petroleum ether, hexane and hot water extracts. The results confirmed the presence of antibacterial and antifungal activity of Carica papaya extract against various human pathogenic bacteria. Presences of phytochemical and antimicrobial activity are confirmed.

Carbohydrate-active enzymes from the zygomycete fungus Rhizopus oryzae: a highly specialized approach to carbohydrate degradation depicted at genome level

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Henrissat Bernard

2011-01-01

Full Text Available Abstract Background Rhizopus oryzae is a zygomycete filamentous fungus, well-known as a saprobe ubiquitous in soil and as a pathogenic/spoilage fungus, causing Rhizopus rot and mucomycoses. Results Carbohydrate Active enzyme (CAZy annotation of the R. oryzae identified, in contrast to other filamentous fungi, a low number of glycoside hydrolases (GHs and a high number of glycosyl transferases (GTs and carbohydrate esterases (CEs. A detailed analysis of CAZy families, supported by growth data, demonstrates highly specialized plant and fungal cell wall degrading abilities distinct from ascomycetes and basidiomycetes. The specific genomic and growth features for degradation of easily digestible plant cell wall mono- and polysaccharides (starch, galactomannan, unbranched pectin, hexose sugars, chitin, chitosan, β-1,3-glucan and fungal cell wall fractions suggest specific adaptations of R. oryzae to its environment. Conclusions CAZy analyses of the genome of the zygomycete fungus R. oryzae and comparison to ascomycetes and basidiomycete species revealed how evolution has shaped its genetic content with respect to carbohydrate degradation, after divergence from the Ascomycota and Basidiomycota.

Protein deficiency lowers resistance of Mormon crickets to the pathogenic fungus Beauveria bassiana.

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Srygley, R B; Jaronski, S T

Little is known about the effects of dietary macronutrients on the capacity of insects to ward off a fungal pathogen. Here we tested the hypothesis that Mormon crickets fed restricted protein diets have lower enzymatic assays of generalized immunity, slower rates of encapsulation of foreign bodies, and greater mortality from infection by Beauveria bassiana, a fungal pathogen. Beginning in the last nymphal instar, Mormon crickets were fed a high, intermediate, or low protein diet with correspondingly low, intermediate, or high carbohydrate proportions. After they eclosed to adult, we drew hemolymph, topically applied B. bassiana, maintained them on diet treatments, and measured mortality for 21 days. Mormon crickets fed high protein diets had higher prophenoloxidase titers, greater encapsulation response, and higher survivorship to Beauveria fungal infection than those on low protein diets. We replicated the study adding very high and very low protein diets to the treatments. A high protein diet increased phenoloxidase titers, and those fed the very high protein diet had more circulating prophenoloxidase. Mormon crickets fed the very low protein diet were the most susceptible to B. bassiana infection, but the more concentrated phenoloxidase and prophenoloxidase associated with the highest protein diets did not confer the greatest protection from the fungal pathogen as in the first replicate. We conclude that protein-restricted diets caused Mormon crickets to have lower phenoloxidase titers, slower encapsulation of foreign bodies, and greater mortality from B. bassiana infection than those fed high protein diets. These results support the nutrition-based dichotomy of migrating Mormon crickets, protein-deficient ones are more susceptible to pathogenic fungi whereas carbohydrate-deficient ones are more vulnerable to bacterial challenge. Published by Elsevier Ltd.

Antimicrobial metabolites from the plant endophytic fungus Penicillium sp.

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Yang, Ming-Hua; Li, Tian-Xiao; Wang, Ying; Liu, Rui-Huan; Luo, Jun; Kong, Ling-Yi

2017-01-01

Five rare dichloro aromatic polyketides (1-5) were obtained from an endophytic fungus Penicillium sp., along with five known metabolites (6-10). Their structures were elucidated by extensive spectroscopic analysis, Mosher methods, as well as [Rh 2 (OCOCF 3 ) 4 ]-induced electronic circular dichroism (ECD) experiments. Compounds 2-4 and 6 structurally involved acyclic 1.3-diols, the uneasy configuration determinations of which were well carried out by double-derivation NMR methods. Compounds 1-10 were evaluated for their antibacterial and antifungal activities against five strains of human pathogenic microorganisms. Helvolic acid (7) showed potent inhibitory effects against Staphylococcus aureus and Pseudomonas aeruginosa with MIC (minimum inhibitory concentration) values of 5.8 and 4.6μg/mL, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Transcriptional Analysis Allows Genome Reannotation and Reveals that Cryptococcus gattii VGII Undergoes Nutrient Restriction during Infection

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Patrícia Aline Gröhs Ferrareze

2017-08-01

Full Text Available Cryptococcus gattii is a human and animal pathogen that infects healthy hosts and caused the Pacific Northwest outbreak of cryptococcosis. The inhalation of infectious propagules can lead to internalization of cryptococcal cells by alveolar macrophages, a niche in which C. gattii cells can survive and proliferate. Although the nutrient composition of macrophages is relatively unknown, the high induction of amino acid transporter genes inside the phagosome indicates a preference for amino acid uptake instead of synthesis. However, the presence of countable errors in the R265 genome annotation indicates significant inhibition of transcriptomic analysis in this hypervirulent strain. Thus, we analyzed RNA-Seq data from in vivo and in vitro cultures of C. gattii R265 to perform the reannotation of the genome. In addition, based on in vivo transcriptomic data, we identified highly expressed genes and pathways of amino acid metabolism that would enable C. gattii to survive and proliferate in vivo. Importantly, we identified high expression in three APC amino acid transporters as well as the GABA permease. The use of amino acids as carbon and nitrogen sources, releasing ammonium and generating carbohydrate metabolism intermediaries, also explains the high expression of components of several degradative pathways, since glucose starvation is an important host defense mechanism.

IL-4 receptor-alpha-dependent control of Cryptococcus neoformans in the early phase of pulmonary infection.

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Andreas Grahnert

Full Text Available Cryptococcus neoformans is an opportunistic fungal pathogen that causes lung inflammation and meningoencephalitis in immunocompromised people. Previously we showed that mice succumb to intranasal infection by induction of pulmonary interleukin (IL-4Rα-dependent type 2 immune responses, whereas IL-12-dependent type 1 responses confer resistance. In the experiments presented here, IL-4Rα⁻/⁻ mice unexpectedly show decreased fungal control early upon infection with C. neoformans, whereas wild-type mice are able to control fungal growth accompanied by enhanced macrophage and dendritic cell recruitment to the site of infection. Lower pulmonary recruitment of macrophages and dendritic cells in IL-4Rα⁻/⁻ mice is associated with reduced pulmonary expression of CCL2 and CCL20 chemokines. Moreover, IFN-γ and nitric oxide production are diminished in IL-4Rα⁻/⁻ mice compared to wild-type mice. To directly study the potential mechanism(s responsible for reduced production of IFN-γ, conventional dendritic cells were stimulated with C. neoformans in the presence of IL-4 which results in increased IL-12 production and reduced IL-10 production. Together, a beneficial role of early IL-4Rα signaling is demonstrated in pulmonary cryptococcosis, which contrasts with the well-known IL-4Rα-mediated detrimental effects in the late phase.

The Ste12-like transcription factor MaSte12 is involved in pathogenicity by regulating the appressorium formation in the entomopathogenic fungus, Metarhizium acridum.

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Wei, Qinglv; Du, Yanru; Jin, Kai; Xia, Yuxian

2017-12-01

Homeodomain transcription factor Ste12 is a key target activated by the pathogenic mitogen-activated-protein kinase pathway, and the activated Ste12p protein regulates downstream gene expression levels to modulate phenotypes. However, the functions of Ste12-like genes in entomopathogenic fungi remain poorly understood and little is known about the downstream genes regulated by Ste12. In this study, we characterized the functions of a Ste12 orthologue in Metarhizium acridum, MaSte12, and identified its downstream target genes. The deletion mutant (ΔMaSte12) is defective in conidial germination but not in hyphal growth, conidiation, or stress tolerance. Bioassays showed that ΔMaSte12 had a dramatically decreased virulence in topical inoculations, but no significant difference was found in intrahemolymph injections when the penetration process was bypassed. The mature appressorium formation rate of ΔMaSte12 was less than 10% on locust wings, with the majority hyphae forming appressorium-like, curved but no swollen structures. Digital gene expression profiling revealed that some genes involved in cell wall synthesis and remodeling, appressorium development, and insect cuticle penetration were downregulated in ΔMaSte12. Thus, MaSte12 has critical roles in the pathogenicity of the entomopathogenic fungus M. acridum, and our study provides some explanations for the impairment of fungal virulence in ΔMaSte12. In addition, virulence is very important for fungal biocontrol agents to control insect pests effectively. This study demonstrated that MaSte12 is involved in fungal virulence but not conidial yield or fungal stress tolerance in M. acridum. Thus, MaSte12 and its downstream genes may be candidates for enhancing fungal virulence to improve mycoinsecticides.

Morphological and molecular characterizations of psychrophilic fungus Geomyces destructans from New York bats with White Nose Syndrome (WNS).

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Chaturvedi, Vishnu; Springer, Deborah J; Behr, Melissa J; Ramani, Rama; Li, Xiaojiang; Peck, Marcia K; Ren, Ping; Bopp, Dianna J; Wood, Britta; Samsonoff, William A; Butchkoski, Calvin M; Hicks, Alan C; Stone, Ward B; Rudd, Robert J; Chaturvedi, Sudha

2010-05-24

Massive die-offs of little brown bats (Myotis lucifugus) have been occurring since 2006 in hibernation sites around Albany, New York, and this problem has spread to other States in the Northeastern United States. White cottony fungal growth is seen on the snouts of affected animals, a prominent sign of White Nose Syndrome (WNS). A previous report described the involvement of the fungus Geomyces destructans in WNS, but an identical fungus was recently isolated in France from a bat that was evidently healthy. The fungus has been recovered sparsely despite plentiful availability of afflicted animals. We have investigated 100 bat and environmental samples from eight affected sites in 2008. Our findings provide strong evidence for an etiologic role of G. destructans in bat WNS. (i) Direct smears from bat snouts, Periodic Acid Schiff-stained tissue sections from infected tissues, and scanning electron micrographs of bat tissues all showed fungal structures similar to those of G. destructans. (ii) G. destructans DNA was directly amplified from infected bat tissues, (iii) Isolations of G. destructans in cultures from infected bat tissues showed 100% DNA match with the fungus present in positive tissue samples. (iv) RAPD patterns for all G. destructans cultures isolated from two sites were indistinguishable. (v) The fungal isolates showed psychrophilic growth. (vi) We identified in vitro proteolytic activities suggestive of known fungal pathogenic traits in G. destructans. Further studies are needed to understand whether G. destructans WNS is a symptom or a trigger for bat mass mortality. The availability of well-characterized G. destructans strains should promote an understanding of bat-fungus relationships, and should aid in the screening of biological and chemical control agents.

Evolutionary transition from single to multiple mating in fungus-growing ants

DEFF Research Database (Denmark)

Villesen, Palle; Gertsch, P J; Frydenberg, Jane

1999-01-01

Queens of leafcutter ants exhibit the highest known levels of multiple mating (up to 10 mates per queen) among ants. Multiple mating may have been selected to increase genetic diversity among nestmate workers, which is hypothesized to be critical in social systems with large, long-lived colonies...... under severe pressure of pathogens. Advanced fungus-growing (leafcutter) ants have large numbers (104-106 workers) and long-lived colonies, whereas basal genera in the attine tribe have small (... to have lower queen mating frequencies, similar to those found in most other ants. We tested this prediction by analysing queen mating frequency and colony kin structure in three basal attine species: Myrmicocrypta ednaella, Apterostigma collare and Cyphomyrmex longiscapus. Microsatellite marker analyses...

Cytotoxic and Antimicrobial Compounds from the Marine-Derived Fungus, Penicillium Species

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Diaa T. A. Youssef

2018-02-01

Full Text Available The organic extract of liquid cultures of the marine-derived Penicillium sp. was investigated. Fractionation of the extracts of the fungus led to the purification and identification of two new compounds, penicillatides A (1 and B (2, together with the previously reported cyclo(R-Pro–S-Phe (3 and cyclo(R-Pro–R-Phe (4. The structures of compounds 1–4 were assigned by extensive interpretation of their NMR and high-resolution mass spectrometry (HRMS. The antiproliferative and cytotoxic activities of the compounds against three human cancer cell lines as well as their antimicrobial activity against several pathogens were evaluated. Compounds 2–4 displayed variable cytotoxic and antimicrobial activities.

Scanning electron microscopy of the interaction between Cryptococcus magnus and Colletotrichum gloeosporioides on papaya fruit = Microscopia eletrônica de varredura da interação entre Cryptococcus magnus e Colletotrichum gloeosporioides em frutos de mamão

NARCIS (Netherlands)

Capdeville, G.; Souza, M.T.; Santos, J.R.P.; Miranda, S.P.; Caetano, A.R.; Falcao, R.; Gomes, A.C.M.M.

2007-01-01

The objective of this work was to investigate possible modes of action of the yeast Cryptococcus magnus in controlling anthracnose (Colletotrichum gloeosporioides) on post harvested papaya fruits. Scanning electron microscopy was used to analyze the effect of the yeast on inoculations done after

Tracking the footsteps of an invasive plant pathogen: Intercontinental phylogeographic structure of the white-pine-blister-rust fungus, Cronartium ribicola

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Bryce A. Richardson; Mee-Sook Kim; Ned B. Klopfenstein; Yuko Ota; Kwan Soo Woo; Richard C. Hamelin

2009-01-01

Presently, little is known about the worldwide genetic structure, diversity, or evolutionary relationships of the white-pineblister-rust fungus, Cronartium ribicola. A collaborative international effort is underway to determine the phylogeographic relationships among Asian, European, and North American sources of C. ribicola and...

Production of hydrolytic enzymes by the plant pathogenic fungus Myrothecium verrucaria in submerged cultures Produção de enzimas hidrolíticas pelo fungo fitopatogênico Myrothecium verrucaria em culturas submersas

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Fabiana Guillen Moreira

2005-03-01

Full Text Available The capability of the plant pathogenic fungus Myrothecium verrucaria to produce extracellular hydrolytic enzymes in submerged cultures was studied using several substrates. The fungus was able to produce different depolymerases and glycosidases, being xylanase, pectinase and protease the most important. Lipase was found in cultures developed in the presence of olive oil, while protease activity was detected in all cultures. Xylanase and pectinase were optimally active at pH 4.5-5.5, while protease was active in a large range of pH 3.5 to 11.0. All three enzymes were maximally active at 40ºC and they were stable for several hours at temperature up to 50ºC.A capacidade do fungo fitopatogênico Myrothecium verrucaria produzir enzimas hidrolíticas extracelulares em culturas submersas foi estudada utilizando diversos substratos. O fungo foi capaz de produzir diferentes depolimerases e glicosidases, sendo xilanases, pectinases e proteases as mais importantes. Atividade lipase foi encontrada nos filtrados das culturas desenvolvidas na presença de óleo de oliva, enquanto atividade proteolítica foi detectada em todas as culturas. Xilanase e pectinase foram otimamente ativas em pH 4,5 a 5,5, enquanto protease foi ativa em ampla faixa de pH (3,5 a 11,0. As três enzimas foram otimamente ativas 40ºC e estáveis por várias horas a temperaturas até 50ºC.

Identification and characterization of microRNAs in oilseed rape (Brassica napus) responsive to infection with the pathogenic fungus Verticillium longisporum using Brassica AA (Brassica rapa) and CC (Brassica oleracea) as reference genomes.

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Shen, Dan; Suhrkamp, Ina; Wang, Yu; Liu, Shenyi; Menkhaus, Jan; Verreet, Joseph-Alexander; Fan, Longjiang; Cai, Daguang

2014-11-01

Verticillium longisporum, a soil-borne pathogenic fungus, causes vascular disease in oilseed rape (Brassica napus). We proposed that plant microRNAs (miRNAs) are involved in the plant-V. longisporum interaction. To identify oilseed rape miRNAs, we deep-sequenced two small RNA libraries made from V. longisporum infected/noninfected roots and employed Brassica rapa and Brassica oleracea genomes as references for miRNA prediction and characterization. We identified 893 B. napus miRNAs representing 360 conserved and 533 novel miRNAs, and mapped 429 and 464 miRNAs to the AA and CC genomes, respectively. Microsynteny analysis with the conserved miRNAs and their flanking protein coding sequences revealed 137 AA-CC genome syntenic miRNA pairs and 61 AA and 42 CC genome-unique miRNAs. Sixty-two miRNAs were responsive to the V. longisporum infection. We present data for specific interactions and simultaneously reciprocal changes in the expression levels of the miRNAs and their targets in the infected roots. We demonstrate that miRNAs are involved in the plant-fungus interaction and that miRNA168-Argonaute 1 (AGO1) expression modulation might act as a key regulatory module in a compatible plant-V. longisporum interaction. Our results suggest that V. longisporum may have evolved a virulence mechanism by interference with plant miRNAs to reprogram plant gene expression and achieve infection. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

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Palková, Zdena; Váchová, Libuše

2016-09-01

Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

288-IJBCS-Article-Dr Tene Mathieu

African Journals Online (AJOL)

Dr Gatsing

active antibacterial and antifungal principles supports the use of C. macrostachys in traditional medicine for the treatment of microbial infections. .... Virginia, USA), in addition to one fungus,. Cryptococcus neoformans IP 95026, from. Pasteur ... attention as far back as in the 19th century. (Tolstikova et al., 2006). For all the ...

Different culture media containing methyldopa for melanin production by Cryptococcus species

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Ralciane de Paula Menezes

2011-10-01

Full Text Available INTRODUCTION: Melanin production by species of Cryptococcus is widely used to characterize C. neoformans complex in mycology laboratories. This study aims to test the efficacy of methyldopa from pharmaceutical tablet as a substrate for melanin production, to compare the production of melanin using different agar base added with methyldopa, and to compare the melanin produced in those media with that produced in Niger seed agar and sunflower seed agar by C. neoformans, C. laurentii, and C. albidus. Two isolates of each species, C. neoformans, C. laurentii, and C. albidus, and one of Candida albicans were used to experimentally detect conditions for melanin production. METHODS: The following media were tested: Mueller-Hinton agar (MHA, brain and heart infusion agar (BHIA, blood agar base (BAB, and minimal medium agar (MMA, all added with methyldopa, and the media Niger seed agar (NSA and sunflower seed agar (SSA. RESULTS: All isolates grew in most of the culture media after 24h. Strains planted on media BAB and BHIA showed growth only after 48h. All isolates produced melanin in MMA, MHA, SSA, and NSA media. CONCLUSIONS: Methyldopa in the form pharmaceutical tablet can be used as a substrate for melanin production by Cryptococcus species; minimal medium plus methyldopa was more efficient than the BAB, MHA, and BHIA in the melanin production; and NSA and SSA, followed by MMA added with methyldopa, were more efficient than other media studied for melanin production by all strains studied.

Polymorphic DNA sequences of the fungal honey bee pathogen Ascosphaera apis

DEFF Research Database (Denmark)

Jensen, Annette B; Welker, Dennis L; Kryger, Per

2012-01-01

The pathogenic fungus Ascosphaera apis is ubiquitous in honey bee populations. We used the draft genome assembly of this pathogen to search for polymorphic intergenic loci that could be used to differentiate haplotypes. Primers were developed for five such loci, and the species specificities were...... verified using DNA from nine closely related species. The sequence variation was compared among 12 A. apis isolates at each of these loci, and two additional loci, the internal transcribed spacer of the ribosomal RNA (ITS) and a variable part of the elongation factor 1α (Ef1α). The degree of variation...... was then compared among the different loci, and three were found to have the greatest detection power for identifying A. apis haplotypes. The described loci can help to resolve strain differences and population genetic structures, to elucidate host–pathogen interaction and to test evolutionary hypotheses...

Interaction of Cryptococcus neoformans Rim101 and protein kinase A regulates capsule.

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Teresa R O'Meara

2010-02-01

Full Text Available Cryptococcus neoformans is a prevalent human fungal pathogen that must survive within various tissues in order to establish a human infection. We have identified the C. neoformans Rim101 transcription factor, a highly conserved pH-response regulator in many fungal species. The rim101 multiply sign in circle mutant strain displays growth defects similar to other fungal species in the presence of alkaline pH, increased salt concentrations, and iron limitation. However, the rim101 multiply sign in circle strain is also characterized by a striking defect in capsule, an important virulence-associated phenotype. This capsular defect is likely due to alterations in polysaccharide attachment to the cell surface, not in polysaccharide biosynthesis. In contrast to many other C. neoformans capsule-defective strains, the rim101 multiply sign in circle mutant is hypervirulent in animal models of cryptococcosis. Whereas Rim101 activation in other fungal species occurs through the conserved Rim pathway, we demonstrate that C. neoformans Rim101 is also activated by the cAMP/PKA pathway. We report here that C. neoformans uses PKA and the Rim pathway to regulate the localization, activation, and processing of the Rim101 transcription factor. We also demonstrate specific host-relevant activating conditions for Rim101 cleavage, showing that C. neoformans has co-opted conserved signaling pathways to respond to the specific niche within the infected host. These results establish a novel mechanism for Rim101 activation and the integration of two conserved signaling cascades in response to host environmental conditions.

Modulation of Replicative Lifespan in Cryptococcus neoformans: Implications for Virulence

Science.gov (United States)

Bouklas, Tejas; Jain, Neena; Fries, Bettina C.

2017-01-01

The fungal pathogen, Cryptococcus neoformans, has been shown to undergo replicative aging. Old cells are characterized by advanced generational age and phenotypic changes that appear to mediate enhanced resistance to host and antifungal-based killing. As a consequence of this age-associated resilience, old cells accumulate during chronic infection. Based on these findings, we hypothesized that shifting the generational age of a pathogenic yeast population would alter its vulnerability to the host and affect its virulence. SIR2 is a well-conserved histone deacetylase, and a pivotal target for the development of anti-aging drugs. We tested its effect on C. neoformans’ replicative lifespan (RLS). First, a mutant C. neoformans strain (sir2Δ) was generated, and confirmed a predicted shortened RLS in sir2Δ cells consistent with its known role in aging. Next, RLS analysis showed that treatment of C. neoformans with Sir2p-agonists resulted in a significantly prolonged RLS, whereas treatment with a Sir2p-antagonist shortened RLS. RLS modulating effects were dependent on SIR2 and not observed in sir2Δ cells. Because SIR2 loss resulted in a slightly impaired fitness, effects of genetic RLS modulation on virulence could not be compared with wild type cells. Instead we chose to chemically modulate RLS, and investigated the effect of Sir2p modulating drugs on C. neoformans cells in a Galleria mellonella infection model. Consistent with our hypothesis that shifts in the generational age of the infecting yeast population alters its vulnerability to host cells, we observed decreased virulence of C. neoformans in the Galleria host when RLS was prolonged by treatment with Sir2p agonists. In contrast, treatment with a Sir2p antagonist, which shortens RLS enhanced virulence in Galleria. In addition, combination of Sir2p agonists with antifungal therapy enhanced the antifungal’s effect. Importantly, no difference in virulence was observed with drug treatment when sir2Δ cells

Unisexual and heterosexual meiotic reproduction generate aneuploidy and phenotypic diversity de novo in the yeast Cryptococcus neoformans.

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Min Ni

2013-09-01

Full Text Available Aneuploidy is known to be deleterious and underlies several common human diseases, including cancer and genetic disorders such as trisomy 21 in Down's syndrome. In contrast, aneuploidy can also be advantageous and in fungi confers antifungal drug resistance and enables rapid adaptive evolution. We report here that sexual reproduction generates phenotypic and genotypic diversity in the human pathogenic yeast Cryptococcus neoformans, which is globally distributed and commonly infects individuals with compromised immunity, such as HIV/AIDS patients, causing life-threatening meningoencephalitis. C. neoformans has a defined a-α opposite sexual cycle; however, >99% of isolates are of the α mating type. Interestingly, α cells can undergo α-α unisexual reproduction, even involving genotypically identical cells. A central question is: Why would cells mate with themselves given that sex is costly and typically serves to admix preexisting genetic diversity from genetically divergent parents? In this study, we demonstrate that α-α unisexual reproduction frequently generates phenotypic diversity, and the majority of these variant progeny are aneuploid. Aneuploidy is responsible for the observed phenotypic changes, as chromosome loss restoring euploidy results in a wild-type phenotype. Other genetic changes, including diploidization, chromosome length polymorphisms, SNPs, and indels, were also generated. Phenotypic/genotypic changes were not observed following asexual mitotic reproduction. Aneuploidy was also detected in progeny from a-α opposite-sex congenic mating; thus, both homothallic and heterothallic sexual reproduction can generate phenotypic diversity de novo. Our study suggests that the ability to undergo unisexual reproduction may be an evolutionary strategy for eukaryotic microbial pathogens, enabling de novo genotypic and phenotypic plasticity and facilitating rapid adaptation to novel environments.

Quantitative Proteomics of an Amphibian Pathogen, Batrachochytrium dendrobatidis, following Exposure to Thyroid Hormone.

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Thekkiniath, Jose; Zabet-Moghaddam, Masoud; Kottapalli, Kameswara Rao; Pasham, Mithun R; San Francisco, Susan; San Francisco, Michael

2015-01-01

Batrachochytrium dendrobatidis (Bd), a chytrid fungus, has increasingly been implicated as a major factor in the worldwide decline of amphibian populations. The fungus causes chytridiomycosis in susceptible species leading to massive die-offs of adult amphibians. Although Bd infects the keratinized mouthparts of tadpoles and negatively affects foraging behavior, these infections are non-lethal. An important morphogen controlling amphibian metamorphosis is thyroid hormone (T3). Tadpoles may be infected with Bd and the fungus may be exposed to T3 during metamorphosis. We hypothesize that exposure of Bd to T3 may induce the expression of factors associated with host colonization and pathogenicity. We utilized a proteomics approach to better understand the dynamics of the Bd-T3 interaction. Using liquid chromatography-mass spectrometry (LC-MS), we generated a data set of a large number of cytoplasmic and membrane proteins following exposure of Bd to T3. From these data, we identified a total of 263 proteins whose expression was significantly changed following T3 exposure. We provide evidence for expression of an array of proteins that may play key roles in both genomic and non-genomic actions of T3 in Bd. Additionally, our proteomics study shows an increase in several proteins including proteases and a class of uncommon crinkler and crinkler-like effector proteins suggesting their importance in Bd pathogenicity as well as those involved in metabolism and energy transfer, protein fate, transport and stress responses. This approach provides insights into the mechanistic basis of the Bd-amphibian interaction following T3 exposure.

Quantitative Proteomics of an Amphibian Pathogen, Batrachochytrium dendrobatidis, following Exposure to Thyroid Hormone.

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Jose Thekkiniath

Full Text Available Batrachochytrium dendrobatidis (Bd, a chytrid fungus, has increasingly been implicated as a major factor in the worldwide decline of amphibian populations. The fungus causes chytridiomycosis in susceptible species leading to massive die-offs of adult amphibians. Although Bd infects the keratinized mouthparts of tadpoles and negatively affects foraging behavior, these infections are non-lethal. An important morphogen controlling amphibian metamorphosis is thyroid hormone (T3. Tadpoles may be infected with Bd and the fungus may be exposed to T3 during metamorphosis. We hypothesize that exposure of Bd to T3 may induce the expression of factors associated with host colonization and pathogenicity. We utilized a proteomics approach to better understand the dynamics of the Bd-T3 interaction. Using liquid chromatography-mass spectrometry (LC-MS, we generated a data set of a large number of cytoplasmic and membrane proteins following exposure of Bd to T3. From these data, we identified a total of 263 proteins whose expression was significantly changed following T3 exposure. We provide evidence for expression of an array of proteins that may play key roles in both genomic and non-genomic actions of T3 in Bd. Additionally, our proteomics study shows an increase in several proteins including proteases and a class of uncommon crinkler and crinkler-like effector proteins suggesting their importance in Bd pathogenicity as well as those involved in metabolism and energy transfer, protein fate, transport and stress responses. This approach provides insights into the mechanistic basis of the Bd-amphibian interaction following T3 exposure.

MALDI-TOF MS enables the rapid identification of the major molecular types within the Cryptococcus neoformans/C. gattii species complex.

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Carolina Firacative

Full Text Available BACKGROUND: The Cryptococcus neoformans/C. gattii species complex comprises two sibling species that are divided into eight major molecular types, C. neoformans VNI to VNIV and C. gattii VGI to VGIV. These genotypes differ in host range, epidemiology, virulence, antifungal susceptibility and geographic distribution. The currently used phenotypic and molecular identification methods for the species/molecular types are time consuming and expensive. As Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS offers an effective alternative for the rapid identification of microorganisms, the objective of this study was to examine its potential for the identification of C. neoformans and C. gattii strains at the intra- and inter-species level. METHODOLOGY: Protein extracts obtained via the formic acid extraction method of 164 C. neoformans/C. gattii isolates, including four inter-species hybrids, were studied. RESULTS: The obtained mass spectra correctly identified 100% of all studied isolates, grouped each isolate according to the currently recognized species, C. neoformans and C. gattii, and detected potential hybrids. In addition, all isolates were clearly separated according to their major molecular type, generating greater spectral differences among the C. neoformans molecular types than the C. gattii molecular types, most likely reflecting a closer phylogenetic relationship between the latter. The number of colonies used and the incubation length did not affect the results. No spectra were obtained from intact yeast cells. An extended validated spectral library containing spectra of all eight major molecular types was established. CONCLUSIONS: MALDI-TOF MS is a rapid identification tool for the correct recognition of the two currently recognized human pathogenic Cryptococcus species and offers a simple method for the separation of the eight major molecular types and the detection of hybrid strains within this

Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

DEFF Research Database (Denmark)

Oh, Dong-Chan; Poulsen, Michael; Currie, Cameron R

2009-01-01

Fungus-growing ants engage in mutualistic associations with both the fungus they cultivate for food and actinobacteria (Pseudonocardia spp.) that produce selective antibiotics to defend that fungus from specialized fungal parasites. We have analyzed one such system at the molecular level and found...

Secondary metabolites of Antarctic fungi antagonistic to aquatic pathogenic bacteria

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Zhao Huibin

2018-03-01

Full Text Available Polar microbial derived antibiotics have potential as alternatives to traditional antibiotics in treating fish against pathogenic bacteria. In this paper, 23 strains of polar fungi were fermented to detect bacteriostatic products on three aquatic pathogenic bacteria, subsequently the active fungus was identified. It was indicated that secondary metabolites of 23 strains weredistinct; of these, the extract of strain B-7 (belonging to Bjerkandera according to molecular identification demonstrated a strong antibacterial activity to Streptococcus agalactiae, Vibrio anguillarum and Aeromonas hydrophila ATCC7966 by Kirby-Bauerpaper strip method. During one fermentation cycle, the pH curve of the fermentation liquor became lowest (4.0 on the 4th day and rose back to 7.6 finally after 5 days, The residual sugar curve was decreased before stablising on the 6th day. It is presumed that a large amount of alkaline secondary metabolites might have been produced during fermentation. This study focuses on antagonism between aquatic pathogenic bacteria and fermentation metabolites from Antarctic fungi for the first time, which may provide data on research of antibiotics against aquatic pathogenic bacteria.

Simultaneous Detection of Five Pathogens from Cerebrospinal Fluid Specimens Using Luminex Technology

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Linfu Zhou

2016-02-01

Full Text Available Early diagnosis and treatment are crucial for the outcome of central nervous system (CNS infections. In this study, we developed a multiplex PCR-Luminex assay for the simultaneous detection of five major pathogens, including Mycobacterium tuberculosis, Cryptococcus neoformans, Streptococcus pneumoniae, and herpes simplex virus types 1 and 2, which frequently cause CNS infections. Through the hybridization reaction between multiplex PCR-amplified targets and oligonucleotide “anti-TAG” sequences, we found that the PCR-Luminex assay could detect as low as 101–102 copies of synthetic pathogen DNAs. Furthermore, 163 cerebrospinal fluid (CSF specimens from patients with suspected CNS infections were used to evaluate the efficiency of this multiplex PCR-Luminex method. Compared with Ziehl-Neelsen stain, this assay showed a high diagnostic accuracy for tuberculosis meningitis (sensitivity, 90.7% and specificity, 99.1%. For cryptococcal meningitis, the sensitivity and specificity were 92% and 97.1%, respectively, compared with the May Grunwald Giemsa (MGG stain. For herpes simplex virus types 1 and 2 encephalitis, the sensitivities were 80.8% and 100%, and the specificities were 94.2% and 99%, respectively, compared with Enzyme Linked Immunosorbent Assay (ELISA assays. Taken together, this multiplex PCR-Luminex assay showed potential efficiency for the simultaneous detection of five pathogens and may be a promising supplement to conventional methods for diagnosing CNS infections.

Molecular characterization and antifungal susceptibility of Cryptococcus neoformans strains collected from a single institution in Lima, Peru.

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Bejar, Vilma; Tello, Mercedes; García, Ruth; Guevara, José M; Gonzales, Sofia; Vergaray, German; Valencia, Esther; Abanto, Enma; Ortega-Loayza, Alex G; Hagen, Ferry; Gutierrez, Ericson L

2015-01-01

Cryptococcosis is a fungal infection with a worldwide distribution, mainly caused by Cryptococcus neoformans and Cryptococcus gattii. To molecularly characterize the mating-types, serotypes, genotypes and antifungal susceptibility profiles of a set of retrospectively isolated C. neoformans strains from Lima, Peru. A set of 32 Cryptococcus spp. strains from the Institute of Tropical Medicine of the National University of San Marcos, Lima, Peru, were included in this retrospective study. Twenty-four strains were isolated from patients, while the remaining 8 were isolated from the environment. Using conventional PCR, 27 (84.4%) of the isolates were identified as C. neoformans var. grubii mating-type alpha and serotype A. Using the AFLP fingerprinting, it was shown that 16 (50%) of the C. neoformans strains were genotype AFLP1, 13 (40.6%) were genotype AFLP1B, 2 (6.3%) were genotype AFLP2, and 1 (3.1%) was found to be a hybrid between both C. neoformans varieties (genotype AFLP3). The antifungal susceptibility profiles for amphotericin B, fluconazole and voriconazole showed that all the 32 C. neoformans are sensitive to these antifungal compounds. In this study we observed that C. neoformans var. grubii (AFLP1 and AFLP1B) and C. neoformans var. neoformans (AFLP2) were the only cryptococcal varieties involved. All strains were found to be sensitive to the antifungals tested, results that are consistent with those found in the international literature. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Secondary cell wall formation in Cryptococcus neoformans as a rescue mechanism against acid-induced autolysis.

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Farkas, Vladimír; Takeo, Kanji; Maceková, Danka; Ohkusu, Misako; Yoshida, Soichi; Sipiczki, Matthias

2009-03-01

Growth of the opportunistic yeast pathogen Cryptococcus neoformans in a synthetic medium containing yeast nitrogen base and 1.0-3.0% glucose is accompanied by spontaneous acidification of the medium, with its pH decreasing from the initial 5.5 to around 2.5 in the stationary phase. During the transition from the late exponential to the stationary phase of growth, many cells died as a consequence of autolytic erosion of their cell walls. Simultaneously, there was an increase in an ecto-glucanase active towards beta-1,3-glucan and having a pH optimum between pH 3.0 and 3.5. As a response to cell wall degradation, some cells developed an unusual survival strategy by forming 'secondary' cell walls underneath the original ones. Electron microscopy revealed that the secondary cell walls were thicker than the primary ones, exposing bundles of polysaccharide microfibrils only partially masked by an amorphous cell wall matrix on their surfaces. The cells bearing secondary cell walls had a three to five times higher content of the alkali-insoluble cell wall polysaccharides glucan and chitin, and their chitin/glucan ratio was about twofold higher than in cells from the logarithmic phase of growth. The cell lysis and the formation of the secondary cell walls could be suppressed by buffering the growth medium between pH 4.5 and 6.5.

Modulation of Zinc Homeostasis in Acanthamoeba castellanii as a Possible Antifungal Strategy against Cryptococcus gattii

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Nicole S. Ribeiro

2017-08-01

Full Text Available Cryptococcus gattii is a basidiomycetous yeast that can be found in the environment and is one of the agents of cryptococcosis, a life-threatening disease. During its life cycle, cryptococcal cells take hold inside environmental predators such as amoebae. Despite their evolutionary distance, macrophages and amoebae share conserved similar steps of phagocytosis and microbial killing. To evaluate whether amoebae also share other antifungal strategies developed by macrophages, we investigated nutritional immunity against cryptococcal cells. We focused on zinc homeostasis modulation in Acanthamoeba castellanii infected with C. gattii. The intracellular proliferation rate (IPR in amoebae was determined using C. gattii R265 and mutants for the ZIP1 gene, which displays defects of growth in zinc-limiting conditions. We detected a reduced IPR in cells lacking the ZIP1 gene compared to wild-type strains, suggesting that amoebae produce a low zinc environment to engulfed cells. Furthermore, flow cytometry analysis employing the zinc probe Zinpyr-1 confirmed the reduced concentration of zinc in cryptococcal-infected amoebae. qRT-PCR analysis of zinc transporter-coding genes suggests that zinc export by members of the ZnT family would be involved in the reduced intracellular zinc concentration. These results indicate that amoebae may use nutritional immunity to reduce fungal cell proliferation by reducing zinc availability for the pathogen.

A gravity model for the spread of a pollinator-borne plant pathogen.

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Ferrari, Matthew J; Bjørnstad, Ottar N; Partain, Jessica L; Antonovics, Janis

2006-09-01

Many pathogens of plants are transmitted by arthropod vectors whose movement between individual hosts is influenced by foraging behavior. Insect foraging has been shown to depend on both the quality of hosts and the distances between hosts. Given the spatial distribution of host plants and individual variation in quality, vector foraging patterns may therefore produce predictable variation in exposure to pathogens. We develop a "gravity" model to describe the spatial spread of a vector-borne plant pathogen from underlying models of insect foraging in response to host quality using the pollinator-borne smut fungus Microbotryum violaceum as a case study. We fit the model to spatially explicit time series of M. violaceum transmission in replicate experimental plots of the white campion Silene latifolia. The gravity model provides a better fit than a mean field model or a model with only distance-dependent transmission. The results highlight the importance of active vector foraging in generating spatial patterns of disease incidence and for pathogen-mediated selection for floral traits.

Caracterização bioquímica e molecular de Cryptococcus spp. isolados de excretas ambientais de pombos (Columba livia domestica

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G. Colombo

2015-12-01

Full Text Available Os pombos possuem uma rica diversidade de microrganismo, entre eles fungos sapróbios, como do gênero Cryptococcus, que podem atuar como agentes patogênicos para o homem e animais. Objetivou-se o isolamento, a caracterização bioquímica e a molecular de amostras de Cryptococcus spp. de excretas ambientas de pombos. Foram colhidas 100 amostras ambientais de pontos equidistantes e representativos da área da cidade de Araçatuba, São Paulo. As amostras foram rasteladas do solo de vias públicas, armazenadas em frasco coletor e encaminhadas para o Laboratório de Bacteriologia e Micologia da FMVA, onde foram processadas e cultivadas em duplicata, em placas de Petri contendo ágar Sabouraud dextrose a 4% e Niger. Em seguida, foram incubadas à temperatura ambiente e a 30ºC, respectivamente, por um período não inferior a 15 dias. Após a observação diária, as colônias sugestivas para levedura foram reisoladas em ágar Niger e submetidas a testes bioquímicos para posterior caracterização molecular pela técnica da PCR. Como resultado, a caracterização bioquímica e a molecular isolaram 32 colônias leveduriformes, sendo 8% dos cultivos positivos para Cryptococcus neoformans var. neoformans, 17% para Rhodotorula rubidae e 7% Candida albicans. Pelo exposto, concluiu-se que excretas ambientais de pombos constituem um microfoco para Cryptococcus neoformans var. neoformans e outras leveduras com potencial patogênico, representando um risco à saúde pública, sendo necessárias medidas preventivas, como a higienização com a correta remoção das excretas, a fim de minimizar os riscos de exposição ambiental.

Carbon dioxide sensing in an obligate insect-fungus symbiosis: CO2 preferences of leaf-cutting ants to rear their mutualistic fungus.

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Daniela Römer

Full Text Available Defense against biotic or abiotic stresses is one of the benefits of living in symbiosis. Leaf-cutting ants, which live in an obligate mutualism with a fungus, attenuate thermal and desiccation stress of their partner through behavioral responses, by choosing suitable places for fungus-rearing across the soil profile. The underground environment also presents hypoxic (low oxygen and hypercapnic (high carbon dioxide conditions, which can negatively influence the symbiont. Here, we investigated whether workers of the leaf-cutting ant Acromyrmex lundii use the CO2 concentration as an orientation cue when selecting a place to locate their fungus garden, and whether they show preferences for specific CO2 concentrations. We also evaluated whether levels preferred by workers for fungus-rearing differ from those selected for themselves. In the laboratory, CO2 preferences were assessed in binary choices between chambers with different CO2 concentrations, by quantifying number of workers in each chamber and amount of relocated fungus. Leaf-cutting ants used the CO2 concentration as a spatial cue when selecting places for fungus-rearing. A. lundii preferred intermediate CO2 levels, between 1 and 3%, as they would encounter at soil depths where their nest chambers are located. In addition, workers avoided both atmospheric and high CO2 levels as they would occur outside the nest and at deeper soil layers, respectively. In order to prevent fungus desiccation, however, workers relocated fungus to high CO2 levels, which were otherwise avoided. Workers' CO2 preferences for themselves showed no clear-cut pattern. We suggest that workers avoid both atmospheric and high CO2 concentrations not because they are detrimental for themselves, but because of their consequences for the symbiotic partner. Whether the preferred CO2 concentrations are beneficial for symbiont growth remains to be investigated, as well as whether the observed preferences for fungus

Morphological and molecular characterizations of psychrophilic fungus Geomyces destructans from New York bats with White Nose Syndrome (WNS.

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Vishnu Chaturvedi

Full Text Available BACKGROUND: Massive die-offs of little brown bats (Myotis lucifugus have been occurring since 2006 in hibernation sites around Albany, New York, and this problem has spread to other States in the Northeastern United States. White cottony fungal growth is seen on the snouts of affected animals, a prominent sign of White Nose Syndrome (WNS. A previous report described the involvement of the fungus Geomyces destructans in WNS, but an identical fungus was recently isolated in France from a bat that was evidently healthy. The fungus has been recovered sparsely despite plentiful availability of afflicted animals. METHODOLOGY/PRINCIPAL FINDINGS: We have investigated 100 bat and environmental samples from eight affected sites in 2008. Our findings provide strong evidence for an etiologic role of G. destructans in bat WNS. (i Direct smears from bat snouts, Periodic Acid Schiff-stained tissue sections from infected tissues, and scanning electron micrographs of bat tissues all showed fungal structures similar to those of G. destructans. (ii G. destructans DNA was directly amplified from infected bat tissues, (iii Isolations of G. destructans in cultures from infected bat tissues showed 100% DNA match with the fungus present in positive tissue samples. (iv RAPD patterns for all G. destructans cultures isolated from two sites were indistinguishable. (v The fungal isolates showed psychrophilic growth. (vi We identified in vitro proteolytic activities suggestive of known fungal pathogenic traits in G. destructans. CONCLUSIONS/SIGNIFICANCE: Further studies are needed to understand whether G. destructans WNS is a symptom or a trigger for bat mass mortality. The availability of well-characterized G. destructans strains should promote an understanding of bat-fungus relationships, and should aid in the screening of biological and chemical control agents.

Clonality and α-a recombination in the Australian Cryptococcus gattii VGII population - an emerging outbreak in Australia

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Carriconde, Fabian; Gilgado, Félix; Arthur, Ian; Ellis, David; Malik, Richard; van de Wiele, Nathalie; Robert, Vincent; Currie, Bart J.; Meyer, Wieland

2011-01-01

Cryptococcus gattii is a basidiomycetous yeast that causes life-threatening disease in humans and animals. Within C. gattii, four molecular types are recognized (VGI to VGIV). The Australian VGII population has been in the spotlight since 2005, when it was suggested as the possible origin for the

Infection of Drosophila suzukii with the obligate insect-pathogenic fungus Entomophthora muscae

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Becher, Paul G.; Jensen, Rasmus E.; Natsopoulou, Myrsini E.

2018-01-01

Physiological constraints restrict specialist pathogens from infecting new hosts. From an applied perspective, a narrow host range makes specialist pathogens interesting for targeting specific pest insects since they have minimal direct effects on non-target species. Entomopathogenic fungi of the...

Monoclonal antibodies against peptidorhamnomannans of Scedosporium apiospermum enhance the pathogenicity of the fungus.

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Livia C L Lopes

2010-10-01

Full Text Available Scedosporium apiospermum is part of the Pseudallescheria-Scedosporium complex. Peptidorhamnomannans (PRMs are cell wall glycopeptides present in some fungi, and their structures have been characterized in S. apiospermum, S. prolificans and Sporothrix schenckii. Prior work shows that PRMs can interact with host cells and that the glycopeptides are antigenic. In the present study, three monoclonal antibodies (mAbs, IgG1 to S. apiospermum derived PRM were generated and their effects on S. apiospermum were examined in vitro and in vivo. The mAbs recognized a carbohydrate epitope on PRM. In culture, addition of the PRM mAbs increased S. apiospermum conidia germination and reduced conidial phagocytosis by J774.16 macrophages. In a murine infection model, mice treated with antibodies to PRM died prior to control animals. Thus, PRM is involved in morphogenesis and the binding of this glycopeptide by mAbs enhanced the virulence of the fungus. Further insights into the effects of these glycopeptides on the pathobiology of S. apiospermum may lead to new avenues for preventing and treating scedosporiosis.

Cytotoxic and Antifungal Constituents Isolated from the Metabolites of Endophytic Fungus DO14 from Dendrobium officinale

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Ling-Shang Wu

2015-12-01

Full Text Available Two novel cytotoxic and antifungal constituents, (4S,6S-6-[(1S,2R-1, 2-dihydroxybutyl]-4-hydroxy-4-methoxytetrahydro-2H-pyran-2-one (1, (6S,2E-6-hydroxy-3-methoxy-5-oxodec-2-enoic acid (2, together with three known compounds, LL-P880γ (3, LL-P880α (4, and Ergosta-5,7,22-trien-3b-ol (5 were isolated from the metabolites of endophytic fungi from Dendrobium officinale. The chemical structures were determined based on spectroscopic methods. All the isolated compounds 1–5 were evaluated by cytotoxicity and antifungal effects. Our present results indicated that compounds 1–4 showed notable anti-fungal activities (minimal inhibitory concentration (MIC ≤ 50 μg/mL for all the tested pathogens including Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, Aspergillus fumigatus. In addition, compounds 1–4 possessed notable cytotoxcities against human cancer cell lines of HL-60 cells with the IC50 values of below 100 μM. Besides, compounds 1, 2, 4 and 5 showed strong cytotoxities on the LOVO cell line with the IC50 values were lower than 100 μM. In conclusion, our study suggested that endophytic fungi of D. officinale are great potential resources to discover novel agents for preventing or treating pathogens and tumors.

Cytotoxic and Antifungal Constituents Isolated from the Metabolites of Endophytic Fungus DO14 from Dendrobium officinale.

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Wu, Ling-Shang; Jia, Min; Chen, Ling; Zhu, Bo; Dong, Hong-Xiu; Si, Jin-Ping; Peng, Wei; Han, Ting

2015-12-22

Two novel cytotoxic and antifungal constituents, (4S,6S)-6-[(1S,2R)-1, 2-dihydroxybutyl]-4-hydroxy-4-methoxytetrahydro-2H-pyran-2-one (1), (6S,2E)-6-hydroxy-3-methoxy-5-oxodec-2-enoic acid (2), together with three known compounds, LL-P880γ (3), LL-P880α (4), and Ergosta-5,7,22-trien-3b-ol (5) were isolated from the metabolites of endophytic fungi from Dendrobium officinale. The chemical structures were determined based on spectroscopic methods. All the isolated compounds 1-5 were evaluated by cytotoxicity and antifungal effects. Our present results indicated that compounds 1-4 showed notable anti-fungal activities (minimal inhibitory concentration (MIC) ≤ 50 μg/mL) for all the tested pathogens including Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, Aspergillus fumigatus. In addition, compounds 1-4 possessed notable cytotoxcities against human cancer cell lines of HL-60 cells with the IC50 values of below 100 μM. Besides, compounds 1, 2, 4 and 5 showed strong cytotoxities on the LOVO cell line with the IC50 values were lower than 100 μM. In conclusion, our study suggested that endophytic fungi of D. officinale are great potential resources to discover novel agents for preventing or treating pathogens and tumors.

White-Nose Syndrome Fungus (Geomyces destructans) in Bat, France

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Puechmaille, Sébastien J.; Verdeyroux, Pascal; Fuller, Hubert; Gouilh, Meriadeg Ar; Bekaert, Michaël

2010-01-01

White-nose syndrome is caused by the fungus Geomyces destructans and is responsible for the deaths of >1,000,000 bats since 2006. This disease and fungus had been restricted to the northeastern United States. We detected this fungus in a bat in France and assessed the implications of this finding. PMID:20113562

Interaction between TATA-Binding Protein (TBP and Multiprotein Bridging Factor-1 (MBF1 from the Filamentous Insect Pathogenic Fungus Beauveria bassiana.

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Chi Song

Full Text Available TATA-binding protein (TBP is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1 is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regulator of insect populations and can form intimate associations with certain plants. In order to gain a better understanding of the function of MBF1 in filamentous fungi, its interaction with TBP was demonstrated. The MBF1 and TBP homologs in B. bassiana were cloned and purified from a heterologous E. coli expression system. Whereas purified BbTBP was shown to be able to bind oligonucleotide sequences containing the TATA-motif (Kd ≈ 1.3 nM including sequences derived from the promoters of the B. bassiana chitinase and protease genes. In contrast, BbMBF1 was unable to bind to these same target sequences. However, the formation of a ternary complex between BbMBF1, BbTBP, and a TATA-containing target DNA sequence was seen in agarose gel electrophoretic mobility shift assays (EMSA. These data indicate that BbMBF1 forms direct interactions with BbTBP, and that the complex is capable of binding to DNA sequences containing TATA-motifs, confirming that BbTBP can link BbMBF1 to target sequences as part of the RNA transcriptional machinery in fungi.

Cryptococcal transmigration across a model brain blood-barrier: evidence of the Trojan horse mechanism and differences between Cryptococcus neoformans var. grubii strain H99 and Cryptococcus gattii strain R265.

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Sorrell, Tania C; Juillard, Pierre-Georges; Djordjevic, Julianne T; Kaufman-Francis, Keren; Dietmann, Anelia; Milonig, Alban; Combes, Valery; Grau, Georges E R

2016-01-01

Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg) cause neurological disease and cross the BBB as free cells or in mononuclear phagocytes via the Trojan horse mechanism, although evidence for the latter is indirect. There is emerging evidence that Cn and the North American outbreak Cg strain (R265) more commonly cause neurological and lung disease, respectively. We have employed a widely validated in vitro model of the BBB, which utilizes the hCMEC/D3 cell line derived from human brain endothelial cells (HBEC) and the human macrophage-like cell line, THP-1, to investigate whether transport of dual fluorescence-labelled Cn and Cg across the BBB occurs within macrophages. We showed that phagocytosis of Cn by non-interferon (IFN)-γ stimulated THP-1 cells was higher than that of Cg. Although Cn and Cg-loaded THP-1 bound similarly to TNF-activated HBECs under shear stress, more Cn-loaded macrophages were transported across an intact HBEC monolayer, consistent with the predilection of Cn for CNS infection. Furthermore, Cn exhibited a higher rate of expulsion from transmigrated THP-1 compared with Cg. Our results therefore provide further evidence for transmigration of both Cn and Cg via the Trojan horse mechanism and a potential explanation for the predilection of Cn to cause CNS infection. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Cryptococcus Neoformans en excretas de palomas, suelo y aire de los palomares del perímetro Urbano de Ica, 2002

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Maria Curo

2005-10-01

Full Text Available Objetivos: Aislar e identificar las variedades de Cryptococcus neoformans que existen en excretas de palomas, suelo y ambientes aéreos del perímetro urbano de la ciudad de Ica, Perú. Materiales y métodos: Se colectaron muestras de excretas de palomas, suelo contaminado y aire de palomares entre mayo y julio del año 2002. Para el aislamiento primario se usó agar Sabouraud dextrosa con cloramfenicol. Para la identificación por especie se usaron pruebas convencionales y la determinación de la variedad se evaluó sobre el medio de cultivo agar canavanina glicina azul de bromotimol sódico. Resultados: Se obtuvieron 124 muestras procedentes de palomares de la Facultad de Medicina de la Universidad Nacional San Luis Gonzaga de Ica, capilla del Hospital Socorro, Los viñedos de Santa María, La Victoria y San Joaquín. Se aislaron 26 cepas del género Cryptococcus de las cuales nueve cepas correspondieron a C. neoformans var. neoformans y 17 a Cryptococcus spp. La mayor frecuencia se encontró en la zona del palomar de la Facultad de Medicina. Conclusión: C. neoformans var. neoformans se encuentra en excreta y suelo de las áreas protegidas de los palomares estudiados.

Two rapid pigmentation tests for identification of Cryptococcus neoformans.

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Kaufmann, C S; Merz, W G

1982-01-01

Two tests were developed for the rapid identification of Cryptococcus neoformans based on pigment produced by the organism's phenoloxidase activity. Caffeic acid was incorporated into cornmeal agar, a medium used routinely for yeast identification. When tested on this medium, only C. neoformans isolates produced brown pigment. All other yeasts maintained their normal morphology and did not produce the reaction product. A non-medium-based test was developed for same-day identification of C. neoformans isolates. Paper strips saturated with a buffered L-beta-3,4-dihydroxyphenylalanine-ferric citrate solution were inoculated with isolates and incubated at 37 degrees C. Pigment production occurred only with C. neoformans isolates, many within 60 to 90 min. All other yeasts remained negative. PMID:7040452

The tomato wilt fungus Fusarium oxysporum f. sp. lycopersici shares common ancestors with nonpathogenic F. oxysporum isolated from wild tomatoes in the Peruvian Andes.

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Inami, Keigo; Kashiwa, Takeshi; Kawabe, Masato; Onokubo-Okabe, Akiko; Ishikawa, Nobuko; Pérez, Enrique Rodríguez; Hozumi, Takuo; Caballero, Liliana Aragón; de Baldarrago, Fatima Cáceres; Roco, Mauricio Jiménez; Madadi, Khalid A; Peever, Tobin L; Teraoka, Tohru; Kodama, Motoichiro; Arie, Tsutomu

2014-01-01

Fusarium oxysporum is an ascomycetous fungus that is well-known as a soilborne plant pathogen. In addition, a large population of nonpathogenic F. oxysporum (NPF) inhabits various environmental niches, including the phytosphere. To obtain an insight into the origin of plant pathogenic F. oxysporum, we focused on the tomato (Solanum lycopersicum) and its pathogenic F. oxysporum f. sp. lycopersici (FOL). We collected F. oxysporum from wild and transition Solanum spp. and modern cultivars of tomato in Chile, Ecuador, Peru, Mexico, Afghanistan, Italy, and Japan, evaluated the fungal isolates for pathogenicity, VCG, mating type, and distribution of SIX genes related to the pathogenicity of FOL, and constructed phylogenies based on ribosomal DNA intergenic spacer sequences. All F. oxysporum isolates sampled were genetically more diverse than FOL. They were not pathogenic to the tomato and did not carry SIX genes. Certain NPF isolates including those from wild Solanum spp. in Peru were grouped in FOL clades, whereas most of the NPF isolates were not. Our results suggested that the population of NPF isolates in FOL clades gave rise to FOL by gaining pathogenicity.

Immunotherapy of Cryptococcus infections.

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Antachopoulos, C; Walsh, T J

2012-02-01

Despite appropriate antifungal treatment, the management of cryptococcal disease remains challenging, especially in immunocompromised patients, such as human immunodeficiency virus-infected individuals and solid organ transplant recipients. During the past two decades, our knowledge of host immune responses against Cryptococcus spp. has been greatly advanced, and the role of immunomodulation in augmenting the response to infection has been investigated. In particular, the role of 'protective' Th1 (tumour necrosis factor-α, interferon (IFN)-γ, interleukin (IL)-12, and IL-18) and Th17 (IL-23 and IL-17) and 'non-protective' Th2 (IL-4, IL-10, and IL-13) cytokines has been extensively studied in vitro and in animal models of cryptococcal infection. Immunomodulation with monoclonal antibodies against the capsular polysaccharide glucuronoxylomannan, glucosylceramides, melanin and β-glucan and, lately, with radioimmunotherapy has also yielded promising results in animal models. As a balance between sufficiently protective Th1 responses and excessive inflammation is important for optimal outcome, the effect of immunotherapy may range from beneficial to deleterious, depending on factors related to the host, the infecting organism, and the immunomodulatory regimen. Clinical evidence supporting immunomodulation in patients with cryptococcal infection remains too limited to allow firm recommendations. Limited human data suggest a role for IFN-γ. Identification of surrogate markers characterizing patients' immunological status could possibly suggest candidate patients for immunotherapy and the type of immunomodulation to be administered. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

Identification and Initial Characterization of the Effectors of an Anther Smut Fungus and Potential Host Target Proteins

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Venkata S. Kuppireddy

2017-11-01

Full Text Available (1 Background: Plant pathogenic fungi often display high levels of host specificity and biotrophic fungi; in particular, they must manipulate their hosts to avoid detection and to complete their obligate pathogenic lifecycles. One important strategy of such fungi is the secretion of small proteins that serve as effectors in this process. Microbotryum violaceum is a species complex whose members infect members of the Caryophyllaceae; M. lychnidis-dioicae, a parasite on Silene latifolia, is one of the best studied interactions. We are interested in identifying and characterizing effectors of the fungus and possible corresponding host targets; (2 Methods: In silico analysis of the M. lychnidis-dioicae genome and transcriptomes allowed us to predict a pool of small secreted proteins (SSPs with the hallmarks of effectors, including a lack of conserved protein family (PFAM domains and also localized regions of disorder. Putative SSPs were tested for secretion using a yeast secretion trap method. We then used yeast two-hybrid analyses for candidate-secreted effectors to probe a cDNA library from a range of growth conditions of the fungus, including infected plants; (3 Results: Roughly 50 SSPs were identified by in silico analysis. Of these, 4 were studied further and shown to be secreted, as well as examined for potential host interactors. One of the putative effectors, MVLG_01732, was found to interact with Arabidopsis thaliana calcium-dependent lipid binding protein (AtCLB and with cellulose synthase interactive protein 1 orthologues; and (4 Conclusions: The identification of a pool of putative effectors provides a resource for functional characterization of fungal proteins that mediate the delicate interaction between pathogen and host. The candidate targets of effectors, e.g., AtCLB, involved in pollen germination suggest tantalizing insights that could drive future studies.

Interactions between natural enemies: Effect of a predatory mite on transmission of the fungus Neozygites floridana in two-spotted spider mite populations.

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Trandem, Nina; Berdinesen, Ronny; Pell, Judith K; Klingen, Ingeborg

2016-02-01

Introducing the predatory mite Phytoseiulus persimilis into two-spotted spider mite, Tetranychus urticae, populations significantly increased the proportion of T. urticae infected with the spider mite pathogen Neozygites floridana in one of two experiments. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted (20-40 T. urticae/subsample). Releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone. Copyright © 2016 Elsevier Inc. All rights reserved.

Fungus-insect gall of Phlebopus portentosus.

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Zhang, Chun-Xia; He, Ming-Xia; Cao, Yang; Liu, Jing; Gao, Feng; Wang, Wen-Bing; Ji, Kai-Ping; Shao, Shi-Cheng; Wang, Yun

2015-01-01

Phlebopus portentosus is a popular edible wild mushroom found in the tropical Yunnan, China, and northern Thailand. In its natural habitats, a gall often has been found on some plant roots, around which fungal fruiting bodies are produced. The galls are different from common insect galls in that their cavity walls are not made from plant tissue but rather from the hyphae of P. portentosus. Therefore we have termed this phenomenon "fungus-insect gall". Thus far six root mealy bug species in the family Pseudococcidae that form fungus-insect galls with P. portentosus have been identified: Formicococcus polysperes, Geococcus satellitum, Planococcus minor, Pseudococcus cryptus, Paraputo banzigeri and Rastrococcus invadens. Fungus-insect galls were found on the roots of more than 21 plant species, including Delonix regia, Citrus maxima, Coffea arabica and Artocarpus heterophyllus. Greenhouse inoculation trials showed that fungus-insect galls were found on the roots of A. heterophyllus 1 mo after inoculation. The galls were subglobose to globose, fulvous when young and became dark brown at maturation. Each gall harbored one or more mealy bugs and had a chimney-like vent for ventilation and access to the gall. The cavity wall had three layers. Various shaped mealy bug wax deposits were found inside the wall. Fungal hyphae invaded the epidermis of plant roots and sometimes even the cortical cells during the late stage of gall development. The identity of the fungus inside the cavity was confirmed by molecular methods. © 2015 by The Mycological Society of America.

Identification of factors involved in dimorphism and pathogenicity of Zymoseptoria tritici.

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Alexander Yemelin

Full Text Available A forward genetics approach was applied in order to investigate the molecular basis of morphological transition in the wheat pathogenic fungus Zymoseptoria tritici. Z. tritici is a dimorphic plant pathogen displaying environmentally regulated morphogenetic transition between yeast-like and hyphal growth. Considering the infection mode of Z. tritici, the switching to hyphal growth is essential for pathogenicity allowing the fungus the host invasion through natural openings like stomata. We exploited a previously developed Agrobacterium tumefaciens-mediated transformation (ATMT to generate a mutant library by insertional mutagenesis including more than 10,000 random mutants. To identify genes involved in dimorphic switch, a plate-based screening system was established. With this approach eleven dimorphic switch deficient random mutants were recovered, ten of which exhibited a yeast-like mode of growth and one mutant predominantly growing filamentously, producing high amount of mycelium under different incubation conditions. Using genome walking approach previously established, the T-DNA integration sites were recovered and the disrupted genomic loci of corresponding mutants were identified and validated within reverse genetics approach. As prove of concept, two of the random mutants obtained were selected for further investigation using targeted gene inactivation. Both genes deduced were found to encode known factors, previously characterized in other fungi: Ssk1p being constituent of HOG pathway and Ade5,7p involved in de novo purine biosynthesis. The targeted mutant strains defective in these genes exhibit a drastically impaired virulence within infection assays on whole wheat plants. Moreover exploiting further physiological assays the predicted function for both gene products could be confirmed in concordance with conserved biological role of homologous proteins previously described in other fungal organisms.

Morphological features of Camarosporium pini – the fungus associated to health state degradation in Austrian and Ponderosa pine

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Ivanová Helena

2017-06-01

Full Text Available The subject of this study is escalated occurrence of the pathogenic fungus Camarosporium pini in the needle tissue of symptomatic trees P. nigra and P. ponderosa var. jeffreyi growing in urbanized settings and parks. C. pini induces severe infections and initiates a blight and premature loss of second-year foliage in pine trees. The fungus was identified microscopically and on base of morphological keys. The affected needles displayed a distinct bluish-grey necrotic band in the centre. On the surface of infected needles, there were formed pycnidia producing brown, oval conidia with three transversal and one or two vertical walls. Disease symptoms, some important characteristics in pure culture, and distinctive morphological features of C. pini associated to the health state degradation in Austrian and Ponderosa pine are described and compared. Cumulative effects of these stressful biotic and various abiotic factors may explain the current situation concerning the decline in the P. nigra and P. ponderosa var. jeffreyi in Slovakia.

Optimized integration of T-DNA in the taxol-producing fungus ...

African Journals Online (AJOL)

We previously reported a taxol-producing fungus Pestalotiopsis malicola. There, we described the transformation of the fungus mediated by Agrobacterium tumefaciens. T-DNA carrying the selection marker was transferred into the fungus and randomly integrated into the genome as shown by Southern blotting.

A Fungus-Inducible Pepper Carboxylesterase Exhibits Antifungal Activity by Decomposing the Outer Layer of Fungal Cell Walls.

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Seo, Hyo-Hyoun; Park, Ae Ran; Lee, Hyun-Hwa; Park, Sangkyu; Han, Yun-Jeong; Hoang, Quyen T N; Choi, Gyung Ja; Kim, Jin-Cheol; Kim, Young Soon; Kim, Jeong-Il

2018-05-01

Colletotrichum species are major fungal pathogens that cause devastating anthracnose diseases in many economically important crops. In this study, we observed the hydrolyzing activity of a fungus-inducible pepper carboxylesterase (PepEST) on cell walls of C. gloeosporioides, causing growth retardation of the fungus by blocking appressorium formation. To determine the cellular basis for the growth inhibition, we observed the localization of PepEST on the fungus and found the attachment of the protein on surfaces of conidia and germination tubes. Moreover, we examined the decomposition of cell-wall materials from the fungal surface after reaction with PepEST, which led to the identification of 1,2-dithiane-4,5-diol (DTD) by gas chromatography mass spectrometry analysis. Exogenous DTD treatment did not elicit expression of defense-related genes in the host plant but did trigger the necrosis of C. gloeosporioides. Furthermore, the DTD compound displayed protective effects on pepper fruits and plants against C. gloeosporioides and C. coccodes, respectively. In addition, DTD was also effective in preventing other diseases, such as rice blast, tomato late blight, and wheat leaf rust. Therefore, our results provide evidence that PepEST is involved in hydrolysis of the outmost layer of the fungal cell walls and that DTD has antifungal activity, suggesting an alternative strategy to control agronomically important phytopathogens.

Potentially pathogenic yeasts from soil of children’s recreational areas in the city of Łódź (Poland

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Anna Wójcik

2013-06-01

Full Text Available Objectives: Yeasts may become potential human and animal pathogens, particularly for individuals with a depressed immune system. Their presence in the environment, especially in soil, may favour their spread into human ontocenoses. Materials and Methods: Eighty-four soil samples obtained from 21 children's recreational sites in Łódź in autumn 2010 and spring 2011 were evaluated. The yeasts were isolated by classical microbiological methods and identified on the basis of morphological and biochemical features. Results: The fungi were found in 73.8% and in 69.0% of the examined samples collected in autumn and spring, respectively. Among 97 isolates of yeasts, the species potentially pathogenic to humans and animals were Candida colliculosa, C. guilliermondii, C. humicola, C. inconspicua, C. lambica, C. lusitaniae, C. pelliculosa, C. tropicalis, Cryptococcus albidus, C. laurentii, C. neoformans, C. terreus, Kloeckera japonica, Geotrichum candidum, G. penicillatum, Rhodotorula mucilaginosa, R. glutinis, Saccharomyces cerevisiae, Sporobolomyces salmonicolor and Trichosporon cutaneum. The most frequently isolated fungi included the genus Cryptococcus (38 isolates and two species: Rhodotorula glutinis (15, Trichosporon cutaneum (14. C. neoformans, an etiological factor of cryptococcal meningitis, was present in the sandpits of 3 kindergartens. The Candida species were identified from park playgrounds and school sports fields mainly in autumn 2010 (14 isolates, in spring 2011 - only 1 isolate. The concentration of fungal species in particular samples varied considerably, but in the majority of samples, fungi were present at concentration of up to 1×102 CFU/1 g of soil. Conclusions: Yeasts were present in the soil of parks, schools and kindergarten recreational areas; the fact may pose a health risk to humans, especially to children, and this type of biological pollution should be regarded as a potential public health concern.

Integrated Metabolomics and Morphogenesis Reveal Volatile Signaling of the Nematode-Trapping Fungus Arthrobotrys oligospora.

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Wang, Bai-Le; Chen, Yong-Hong; He, Jia-Ning; Xue, Hua-Xi; Yan, Ni; Zeng, Zhi-Jun; Bennett, Joan W; Zhang, Ke-Qin; Niu, Xue-Mei

2018-05-01

The adjustment of metabolic patterns is fundamental to fungal biology and plays vital roles in adaptation to diverse ecological challenges. Nematode-trapping fungi can switch their lifestyle from saprophytic to pathogenic by developing specific trapping devices induced by nematodes to infect their prey as a response to nutrient depletion in nature. However, the chemical identity of the specific fungal metabolites used during the switch remains poorly understood. We hypothesized that these important signal molecules might be volatile in nature. Gas chromatography-mass spectrometry was used to carry out comparative analysis of fungal metabolomics during the saprophytic and pathogenic lifestyles of the model species Arthrobotrys oligospora Two media commonly used in research on this species, cornmeal agar (CMA) and potato dextrose agar (PDA), were chosen for use in this study. The fungus produced a small group of volatile furanone and pyrone metabolites that were associated with the switch from the saprophytic to the pathogenic stage. A. oligospora fungi grown on CMA tended to produce more traps and employ attractive furanones to improve the utilization of traps, while fungi grown on PDA developed fewer traps and used nematode-toxic furanone metabolites to compensate for insufficient traps. Another volatile pyrone metabolite, maltol, was identified as a morphological regulator for enhancing trap formation. Deletion of the gene AOL_s00079g496 in A. oligospora led to increased amounts of the furanone attractant (2-fold) in mutants and enhanced the attractive activity (1.5-fold) of the fungus, while it resulted in decreased trap formation. This investigation provides new insights regarding the comprehensive tactics of fungal adaptation to environmental stress, integrating both morphological and metabolomic mechanisms. IMPORTANCE Nematode-trapping fungi are a unique group of soil-living fungi that can switch from the saprophytic to the pathogenic lifestyle once they come

Functions and regulation of the Nox family in the filamentous fungus Podospora anserina: a new role in cellulose degradation.

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Brun, Sylvain; Malagnac, Fabienne; Bidard, Frédérique; Lalucque, Hervé; Silar, Philippe

2009-10-01

NADPH oxidases are enzymes that produce reactive oxygen species. Studies in mammals, plants and fungi have shown that they play important roles in differentiation, defence, host/pathogen interaction and mutualistic symbiosis. In this paper, we have identified a Podospora anserina mutant strain impaired for processes controlled by PaNox1 and PaNox2, the two Nox isoforms characterized in this model ascomycete. We show that the gene mutated is PaNoxR, the homologue of the gene encoding the regulatory subunit p67(phox), conserved in mammals and fungi, and that PaNoxR regulates both PaNox1 and PaNox2. Genome sequence analysis of P. anserina reveals that this fungus posses a third Nox isoform, PaNox3, related to human Nox5/Duox and plant Rboh. We have generated a knock-out mutant of PaNox3 and report that PaNox3 plays a minor role in P. anserina, if any. We show that PaNox1 and PaNox2 play antagonist roles in cellulose degradation. Finally, we report for the first time that a saprobic fungus, P. anserina, develops special cell structures dedicated to breach and to exploit a solid cellulosic substrate, cellophane. Importantly, as for similar structures present in some plant pathogens, their proper differentiation requires PaNox1, PaNox2, PaNoxR and the tetraspanin PaPls1.

First detection of the larval chalkbrood disease pathogen Ascosphaera apis (Ascomycota: Eurotiomycetes: Ascosphaerales in adult bumble bees.

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Sarah A Maxfield-Taylor

Full Text Available Fungi in the genus Ascosphaera (Ascomycota: Eurotiomycetes: Ascosphaerales cause chalkbrood disease in larvae of bees. Here, we report the first-ever detection of the fungus in adult bumble bees that were raised in captivity for studies on colony development. Wild queens of Bombus griseocollis, B. nevadensis and B. vosnesenskii were collected and maintained for establishment of nests. Queens that died during rearing or that did not lay eggs within one month of capture were dissected, and tissues were examined microscopically for the presence of pathogens. Filamentous fungi that were detected were plated on artificial media containing broad spectrum antibiotics for isolation and identification. Based on morphological characters, the fungus was identified as Ascosphaera apis (Maasen ex Claussen Olive and Spiltoir, a species that has been reported earlier only from larvae of the European honey bee, Apis mellifera, the Asian honey bee, Apis cerana, and the carpenter bee Xylocopa californica arizonensis. The identity of the fungus was confirmed using molecular markers and phylogenetic analysis. Ascosphaera apis was detected in queens of all three bumble bee species examined. Of 150 queens dissected, 12 (8% contained vegetative and reproductive stages of the fungus. Both fungal stages were also detected in two workers collected from colonies with Ascosphaera-infected B. nevadensis queens. In this study, wild bees could have been infected prior to capture for rearing, or, the A. apis infection could have originated via contaminated European honey bee pollen fed to the bumble bees in captivity. Thus, the discovery of A. apis in adult bumble bees in the current study has important implications for commercial production of bumble bee colonies and highlights potential risks to native bees via pathogen spillover from infected bees and infected pollen.

First detection of the larval chalkbrood disease pathogen Ascosphaera apis (Ascomycota: Eurotiomycetes: Ascosphaerales) in adult bumble bees.

Science.gov (United States)

Maxfield-Taylor, Sarah A; Mujic, Alija B; Rao, Sujaya

2015-01-01

Fungi in the genus Ascosphaera (Ascomycota: Eurotiomycetes: Ascosphaerales) cause chalkbrood disease in larvae of bees. Here, we report the first-ever detection of the fungus in adult bumble bees that were raised in captivity for studies on colony development. Wild queens of Bombus griseocollis, B. nevadensis and B. vosnesenskii were collected and maintained for establishment of nests. Queens that died during rearing or that did not lay eggs within one month of capture were dissected, and tissues were examined microscopically for the presence of pathogens. Filamentous fungi that were detected were plated on artificial media containing broad spectrum antibiotics for isolation and identification. Based on morphological characters, the fungus was identified as Ascosphaera apis (Maasen ex Claussen) Olive and Spiltoir, a species that has been reported earlier only from larvae of the European honey bee, Apis mellifera, the Asian honey bee, Apis cerana, and the carpenter bee Xylocopa californica arizonensis. The identity of the fungus was confirmed using molecular markers and phylogenetic analysis. Ascosphaera apis was detected in queens of all three bumble bee species examined. Of 150 queens dissected, 12 (8%) contained vegetative and reproductive stages of the fungus. Both fungal stages were also detected in two workers collected from colonies with Ascosphaera-infected B. nevadensis queens. In this study, wild bees could have been infected prior to capture for rearing, or, the A. apis infection could have originated via contaminated European honey bee pollen fed to the bumble bees in captivity. Thus, the discovery of A. apis in adult bumble bees in the current study has important implications for commercial production of bumble bee colonies and highlights potential risks to native bees via pathogen spillover from infected bees and infected pollen.

Badania nad patogenicznością grzyba Rhizoctonia solani Kühn na lnie [Investigations of Rhizoctonia solani Kühn pathogenicity to flax

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St. Sadowski

2015-06-01

Full Text Available The investigations on the pathogenicity of four Rhizoctonia solani isolates were carried out in relation to three varieties of flax; LCSD - 210, LCSD - 200 and Wiera. Variety LCSD - 210 was found to be the most resistant. Isolates obtaind from flax and potatoes were especially pathogenic. Rhizoctonia solani was parasitic during the whole vegetation season, but particularly in the course of emergence. Parasitism of this fungus is of great economical significance.

Species-level correlates of susceptibility to the pathogenic amphibian fungus Batrachochytrium dendrobatidis in the United States

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Betsy A. Bancroft; Barbara A. Han; Catherine L. Searle; Lindsay M. Biga; Deanna H. Olson; Lee B. Kats; Joshua J. Lawler; Andrew R. Blaustein

2011-01-01

Disease is often implicated as a factor in population declines of wildlife and plants. Understanding the characteristics that may predispose a species to infection by a particular pathogen can help direct conservation efforts. Recent declines in amphibian populations world-wide are a major conservation issue and may be caused in part by a fungal pathogen, ...

Towards an integrated understanding of the consequences of fungus domestication on the fungus-growing termite gut microbiota

DEFF Research Database (Denmark)

Thomas-Poulsen, Michael

2015-01-01

Approximately 30 million years ago (MYA), the subfamily of higher termites Macrotermitinae domesticated a fungus, Termitomyces, as the main plant decomposer and food source for the termite host. The origin of fungiculture shifted the composition of the termite gut microbiota, and some of the func......Approximately 30 million years ago (MYA), the subfamily of higher termites Macrotermitinae domesticated a fungus, Termitomyces, as the main plant decomposer and food source for the termite host. The origin of fungiculture shifted the composition of the termite gut microbiota, and some...... will be powerful, particularly if executed in comparative analyses across the well-established congruent termite-fungus phylogenies. This will allow for testing if gut communities have evolved in parallel with their hosts, with implications for our general understanding of the evolution of gut symbiont communities...

Caterpillars and fungal pathogens: two co-occurring parasites of an ant-plant mutualism.

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Olivier Roux

Full Text Available In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes, that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth.

Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae

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Boknam Jung

2013-12-01

Full Text Available The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

Population structure of the ash dieback pathogen, Hymenoscyphus fraxineus, in relation to its mode of arrival in the UK.

Science.gov (United States)

Orton, E S; Brasier, C M; Bilham, L J; Bansal, A; Webber, J F; Brown, J K M

2018-02-01

The ash dieback fungus, Hymenoscyphus fraxineus , a destructive, alien pathogen of common ash ( Fraxinus excelsior ), has spread across Europe over the past 25 years and was first observed in the UK in 2012. To investigate the relationship of the pathogen's population structure to its mode of arrival, isolates were obtained from locations in England and Wales, either where established natural populations of ash had been infected by wind-dispersed ascospores or where the fungus had been introduced on imported planting stock. Population structure was determined by tests for vegetative compatibility (VC), mating type and single-nucleotide polymorphisms (SNPs). VC heterogeneity was high at all locations, with 96% of isolate pairings being incompatible. Frequencies of the MAT1-1-1 and MAT1-2-1 idiomorphs were approximately equal, consistent with H. fraxineus being an obligate outbreeder. Most SNP variation occurred within study location and there was little genetic differentiation between the two types of location in the UK, or between pathogen populations in the UK and continental Europe. There was modest differentiation between UK subpopulations, consistent with genetic variation between source populations in continental Europe. However, there was no evidence of strong founder effects, indicating that numerous individuals of H. fraxineus initiated infection at each location, regardless of the route of pathogen transmission. The ssRNA virus HfMV1 was present at moderate to high frequencies in all UK subpopulations. The results imply that management of an introduced plant pathogen requires action against its spread at the continental level involving coordinated efforts by European countries.

Cryptococcus lacticolor sp. nov. and Rhodotorula oligophaga sp. nov., novel yeasts isolated from the nasal smear microbiota of Queensland koalas kept in Japanese zoological parks.

Science.gov (United States)

Satoh, Kazuo; Maeda, Mari; Umeda, Yoshiko; Sugamata, Miho; Makimura, Koichi

2013-07-01

A total of 515 yeast strains were isolated from the nasal smears of Queensland koalas and their breeding environments in Japanese zoological parks between 2005 and 2012. The most frequent species in the basidiomycetous yeast biota isolated from koala nasal passages was Cryptococcus neoformans, followed by Rhodotorula minuta. R. minuta was the most frequent species in the breeding environments, while C. neoformans was rare. Seven strains representing two novel yeast species were identified. Analyses of the 26S rDNA (LSU) D1/D2 domain and nuclear ribosomal DNA internal transcribed spacer region sequences indicated that these strains represent new species with close phylogenetic relationships to Cryptococcus and Rhodotorula. A sexual state was not found for either of these two novel yeasts. Key phenotypic characters confirmed that these strains could be placed in Cryptococcus and Rhodotorula. The names Cryptococcus lacticolor sp. nov. (type strain TIMM 10013(T) = JCM 15449(T) = CBS 10915(T) = DSM 21093(T), DDBJ/EMBL/Genbank Accession No.; AB375774 (ITS) and AB375775 (26S rDNA D1/D2 region), MycoBank ID; MB 802688, Fungal Barcoding Database ID; 3174), and Rhodotorula oligophaga sp. nov. (type strain TIMM 10017(T) = JCM 18398(T) = CBS 12623(T) = DSM 25814(T), DDBJ/EMBL/Genbank Accession No.; AB702967 (ITS) and AB702967 (26S rDNA D1/D2 region), MycoBank ID; MB 802689, Fungal Barcoding Database ID; 3175) are proposed for these new species.

A novel antibacterial and antifungal phenolic compound from the endophytic fungus Pestalotiopsis mangiferae.

Science.gov (United States)

Subban, Kamalraj; Subramani, Ramesh; Johnpaul, Muthumary

2013-01-01

A novel phenolic compound, 4-(2,4,7-trioxa-bicyclo[4.1.0]heptan-3-yl) phenol (1), was isolated from Pestalotiopsis mangiferae, an endophytic fungus associated with Mangifera indica Linn. The structure of the compound was elucidated on the basis of comprehensive spectral analysis (UV, IR, ¹H-, ¹³C- and 2D-NMR, as well as HRESI-MS). Compound (1) shows potent antibacterial and antifungal activity against Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa and Candida albicans. The transmission electron microscope study for the mode of inhibition of compound (1) on bacterial pathogens revealed the destruction of bacterial cells by cytoplasm agglutination with the formation of pores in cell wall membranes.

Fenoloxidasa Modificada: Clave para identificar cepas de Cryptococcus neoformans

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Carlos Canelo D

2000-01-01

Full Text Available Cryptococcus neoformans es la única levadura patógena capaz de sintetizar pigmentos como la melanina mediante la actividad de su enzima llamada fenoloxidasa. El objetivo del presente estudio fue implementar y estandarizar la prueba de la fenoloxidasa, como técnica complementaria en la identificación de cepas de C. neoformans. Se estudiaron 21 cepas, identificadas previamente con métodos convencionales. La prueba de la fenoloxidasa fue modificada debido a que su empleo originaba 9,6% (2/21 de falsa negatividad. Esta prueba modificada se optimizó a 28°C a partir de un medio con baja concentración de glucosa. Ningún aislamiento falso negativo fue encontrado luego de repetir tres veces el ensayo, y el pigmento melanina fue detectado con mayor rapidez.

[Cyptococcus gattii isolated from a cheetah (Acinonyx jubatus) in the National Zoo of Cuba].

Science.gov (United States)

Polo Leal, Jorge Luis; Fernández Andreu, Carlos Manuel; Martínez Machín, Gerardo; Illnait Zaragozi, María Teresa; Perurena Lancha, Mayda Rosa

2010-01-01

Cryptoccosis--systemic mycosis caused by Cryptococcus species--has considerably raised its incidence in the last years, mainly associated with the human immunodeficiency virus infection. It has also been described in animals, but rare cases. a case of a female cheetah (Acinonyx jubatus) kept in the Nacional Zoo of Havana was presented. The animal came from South Africa. She began losing weight, and suffering asthenia, anorexia and breathing problems with abundant nasal secretion. mycological testing of these secretions disclosed the presence of serotype B Cryptococcus gattii. Because of the origin and captive condition of the animal, it was believed that the infection had been latent for 16 months at least. up to the present, in Cuba, all clinical Cryptococcus isolates were C. neoformans var. grubii, so it is considered that the infection was caught in the country of origin of the female cheetah. This is the first C. gattii isolate in Cuba from an animal coming from South Africa where this fungus is endemic.

Studies towards the Intrinsic Function of the AVR4 and AVR9 Elicitors of the Fungal Tomato Pathogen Cladosporium fulvum

NARCIS (Netherlands)

Burg, van den H.A.

2003-01-01

Recognition of the extracellular race-specific elicitor proteins AVR4 and AVR9 produced by the pathogenic fungus Cladosporium fulvum is mediated by the tomato resistance genes Cf-4 and Cf-9 , respectively. Recognition of these elicitors triggers host defense responses

Genotypic and Phenotypic Diversity of Cryptococcus gattii VGII Clinical Isolates and Its Impact on Virulence

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Vanessa A. Barcellos

2018-02-01

Full Text Available The Cryptococcus gattii species complex harbors the main etiological agents of cryptococcosis in immunocompetent patients. C. gattii molecular type VGII predominates in the north and northeastern regions of Brazil, leading to high morbidity and mortality rates. C. gattii VGII isolates have a strong clinical relevance and phenotypic variations. These phenotypic variations among C. gattii species complex isolates suggest that some strains are more virulent than others, but little information is available related to the pathogenic properties of those strains. In this study, we analyzed some virulence determinants of C. gattii VGII strains (CG01, CG02, and CG03 isolated from patients in the state of Piauí, Brazil. The C. gattii R265 VGIIa strain, which was isolated from the Vancouver outbreak, differed from C. gattii CG01, CG02 and CG03 isolates (also classified as VGII when analyzed the capsular dimensions, melanin production, urease activity, as well as the glucuronoxylomannan (GXM secretion. Those differences directly reflected in their virulence potential. In addition, CG02 displayed higher virulence compared to R265 (VGIIa strain in a cryptococcal murine model of infection. Lastly, we examined the genotypic diversity of these strains through Multilocus Sequence Type (MLST and one new subtype was described for the CG02 isolate. This study confirms the presence and the phenotypic and genotypic diversity of highly virulent strains in the Northeast region of Brazil.

Transcriptome sequencing of Mycosphaerella fijiensis during association with Musa acuminata reveals candidate pathogenicity genes.

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Noar, Roslyn D; Daub, Margaret E

2016-08-30

Mycosphaerella fijiensis, causative agent of the black Sigatoka disease of banana, is considered the most economically damaging banana disease. Despite its importance, the genetics of pathogenicity are poorly understood. Previous studies have characterized polyketide pathways with possible roles in pathogenicity. To identify additional candidate pathogenicity genes, we compared the transcriptome of this fungus during the necrotrophic phase of infection with that during saprophytic growth in medium. Transcriptome analysis was conducted, and the functions of differentially expressed genes were predicted by identifying conserved domains, Gene Ontology (GO) annotation and GO enrichment analysis, Carbohydrate-Active EnZymes (CAZy) annotation, and identification of genes encoding effector-like proteins. The analysis showed that genes commonly involved in secondary metabolism have higher expression in infected leaf tissue, including genes encoding cytochrome P450s, short-chain dehydrogenases, and oxidoreductases in the 2-oxoglutarate and Fe(II)-dependent oxygenase superfamily. Other pathogenicity-related genes with higher expression in infected leaf tissue include genes encoding salicylate hydroxylase-like proteins, hydrophobic surface binding proteins, CFEM domain-containing proteins, and genes encoding secreted cysteine-rich proteins characteristic of effectors. More genes encoding amino acid transporters, oligopeptide transporters, peptidases, proteases, proteinases, sugar transporters, and proteins containing Domain of Unknown Function (DUF) 3328 had higher expression in infected leaf tissue, while more genes encoding inhibitors of peptidases and proteinases had higher expression in medium. Sixteen gene clusters with higher expression in leaf tissue were identified including clusters for the synthesis of a non-ribosomal peptide. A cluster encoding a novel fusicoccane was also identified. Two putative dispensable scaffolds were identified with a large proportion of

FIRST REPORT ON Cryptococcus neoformans IN PIGEON EXCRETA FROM PUBLIC AND RESIDENTIAL LOCATIONS IN THE METROPOLITAN AREA OF CUIABÁ, STATE OF MATO GROSSO, BRAZIL

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Doracilde Terumi Takahara

2013-12-01

Full Text Available SUMMARY Cryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformans was evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5, churches (n = 4, educational institutions (n = 3, health units (n = 8, open areas covered with asbestos (n = 4, residences (n = 23, factory (n = 1 and a prison (n = 1. Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA. Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6% samples corresponding to six (12.2% locations. Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

Fungal cell gigantism during mammalian infection.

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Oscar Zaragoza

2010-06-01

Full Text Available The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 microm in diameter and capsules resistant to stripping with gamma-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20-50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens.

Fungal cell gigantism during mammalian infection.

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Zaragoza, Oscar; García-Rodas, Rocío; Nosanchuk, Joshua D; Cuenca-Estrella, Manuel; Rodríguez-Tudela, Juan Luis; Casadevall, Arturo

2010-06-17

The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 microm in diameter and capsules resistant to stripping with gamma-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20-50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens.

Factors affecting the sporulation capacity during long-term storage of the aphid-pathogenic fungus Pandora neoaphidis grown on broomcorn millet.

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Feng, Ming-Guang; Hua, Li

2005-04-15

Aphid-pathogenic fungus, Pandora neoaphidis, grown on broomcorn millet possesses greater sporulation capacity (C(s)) than aphid cadavers. The most sporulating cultures (32.0x10(4) spores millet(-1) grain) with water content (C(w)) of 48.7% were prepared by incubation at 20 degrees C for 15 days and used to study the effect of temperature and humidity on C(s) during long-term storage. Cultures were sealed with paper to retain ambient humidity, with parafilm for saturated humidity, or kept in 85% and 98% RH chambers. The C(w) and C(s) were monitored during 200-day storage at 5-20 degrees C. The paper-sealed cultures at 5 degrees C, associated with 21-25% of C(w), were best preserved and their 120-day C(s) was similar to that of the fresh cadavers. Consistently or variably high RH at 5 degrees C resulted in significantly higher C(w) and lower C(s) despite longer viability. The regimes at 10 degrees C preserved the cultures for 40 days. The observations fit well to the logistic model C(s)=35.28/{1+exp[-2.36+(-0.003C(w)+0.001C(w)T)t]} (r(2)=0.95) for all regimes of temperature (T) or C(s)=35.55/[1+exp(-2.33+0.001C(w)t)] (r(2)=0.93) at 5 degrees C only. The rate of decline of C(s) of -0.003C(w)+0.001C(w)T or 0.001 C(w) over days (t) highlights the primary effect of C(w). The daily C(s)-decline rates obtained for the best-stored cultures and air-dried cadavers stored at 5 degrees C were surprisingly identical. The results suggest a possible cheap method for preparing and storing large quantities of P. neoaphiodis inocula.

First reported case of Cryptococcus gattii in the Southeastern USA: implications for travel-associated acquisition of an emerging pathogen.

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Edmond J Byrnes

2009-06-01

Full Text Available In 2007, the first confirmed case of Cryptococcus gattii was reported in the state of North Carolina, USA. An otherwise healthy HIV negative male patient presented with a large upper thigh cryptococcoma in February, which was surgically removed and the patient was started on long-term high-dose fluconazole treatment. In May of 2007, the patient presented to the Duke University hospital emergency room with seizures. Magnetic resonance imaging revealed two large CNS lesions found to be cryptococcomas based on brain biopsy. Prior chest CT imaging had revealed small lung nodules indicating that C. gattii spores or desiccated yeast were likely inhaled into the lungs and dissemination occurred to both the leg and CNS. The patient's travel history included a visit throughout the San Francisco, CA region in September through October of 2006, consistent with acquisition during this time period. Cultures from both the leg and brain biopsies were subjected to analysis. Based on phenotypic and molecular methods, both isolates were C. gattii, VGI molecular type, and distinct from the Vancouver Island outbreak isolates. Based on multilocus sequence typing of coding and noncoding regions and virulence in a heterologous host model, the leg and brain isolates are identical, but the two differed in mating fertility. Two clinical isolates, one from a transplant recipient in San Francisco and the other from Australia, were identical to the North Carolina clinical isolate at all markers tested. Closely related isolates that differ at only one or a few noncoding markers are present in the Australian environment. Taken together, these findings support a model in which C. gattii VGI was transferred from Australia to California, possibly though an association with its common host plant E. camaldulensis, and the patient was exposed in San Francisco and returned to present with disease in North Carolina.

CHARACTERIZATION OF AN ANAEROBIC FUNGUS FROM LLAMA FECES

NARCIS (Netherlands)

MARVINSIKKEMA, FD; LAHPOR, GA; KRAAK, MN; GOTTSCHAL, JC; PRINS, RA

1992-01-01

An anaerobic fungus was isolated from Hama faeces. Based on its morphological characteristics, polyflagellated zoospores, extensive rhizoid system and the formation of monocentric colonies, the fungus is assigned to the genus Neocallimastix. Neocallimastix sp. L2 is able to grow on several poly-,

Pathogenic and Nonpathogenic Lifestyles in Colletotrichum acutatum from Strawberry and Other Plants.

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Freeman, S; Horowitz, S; Sharon, A

2001-10-01

ABSTRACT Anthracnose is one of the major fungal diseases of strawberry occurring worldwide. In Israel, the disease is caused primarily by the species Colletotrichum acutatum. The pathogen causes black spot on fruit, root necrosis, and crown rot resulting in mortality of transplants in the field. The host range and specificity of C. acutatum from strawberry was examined on pepper, eggplant, tomato, bean, and strawberry under greenhouse conditions. The fungus was recovered from all plant species over a 3-month period but caused disease symptoms only on strawberry. Epiphytic and endophytic (colonization) fungal growth in the different plant species was confirmed by reisolation from leaf tissues and by polymerase chain reaction (PCR)-specific primer amplification. C. acutatum was also isolated from healthy looking, asymptomatic plants of the weed genera Vicia and Conyza. Isolates that were recovered from the weeds caused disease symptoms on strawberry and were positively identified as C. acutatum by PCR. The habitation of a large number of plant species, including weeds, by C. acutatum suggests that, although it causes disease only on strawberry and anemone in Israel, this fungus can persist on many other plant species. Therefore, plants that are not considered hosts of C. acutatum may serve as a potential inoculum source for strawberry infection and permit survival of the pathogen between seasons.

Toward an integrated model of capsule regulation in Cryptococcus neoformans.

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Brian C Haynes

2011-12-01

Full Text Available Cryptococcus neoformans is an opportunistic fungal pathogen that causes serious human disease in immunocompromised populations. Its polysaccharide capsule is a key virulence factor which is regulated in response to growth conditions, becoming enlarged in the context of infection. We used microarray analysis of cells stimulated to form capsule over a range of growth conditions to identify a transcriptional signature associated with capsule enlargement. The signature contains 880 genes, is enriched for genes encoding known capsule regulators, and includes many uncharacterized sequences. One uncharacterized sequence encodes a novel regulator of capsule and of fungal virulence. This factor is a homolog of the yeast protein Ada2, a member of the Spt-Ada-Gcn5 Acetyltransferase (SAGA complex that regulates transcription of stress response genes via histone acetylation. Consistent with this homology, the C. neoformans null mutant exhibits reduced histone H3 lysine 9 acetylation. It is also defective in response to a variety of stress conditions, demonstrating phenotypes that overlap with, but are not identical to, those of other fungi with altered SAGA complexes. The mutant also exhibits significant defects in sexual development and virulence. To establish the role of Ada2 in the broader network of capsule regulation we performed RNA-Seq on strains lacking either Ada2 or one of two other capsule regulators: Cir1 and Nrg1. Analysis of the results suggested that Ada2 functions downstream of both Cir1 and Nrg1 via components of the high osmolarity glycerol (HOG pathway. To identify direct targets of Ada2, we performed ChIP-Seq analysis of histone acetylation in the Ada2 null mutant. These studies supported the role of Ada2 in the direct regulation of capsule and mating responses and suggested that it may also play a direct role in regulating capsule-independent antiphagocytic virulence factors. These results validate our experimental approach to dissecting

Endogenous Cryptococcus neoformans endophthalmitis with subretinal abscess in a HIV-infected man.

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Joseph, Joveeta; Sharma, Savitri; Narayanan, Raja

2018-07-01

To report a rare case of Cryptococcus neoformans endogenous endophthalmitis with subretinal abscess in a 36-year-old HIV-positive man, referred with progressive blurred vision in his right eye for the last 6 months. Vitreous biopsy followed by intravitreal ganciclovir did not result in significant improvement. Microbiology revealed the presence of C. neoformans, and intravitreal amphotericin B was then administered. The patient was treated aggressively with systemic and intravitreal antifungals but had a poor visual and anatomical outcome. A high degree of clinical suspicion combined with microbiological evaluation helped to arrive at an appropriate diagnosis.

Termite-egg mimicry by a sclerotium-forming fungus.

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Matsuura, Kenji

2006-05-22

Mimicry has evolved in a wide range of organisms and encompasses diverse tactics for defence, foraging, pollination and social parasitism. Here, I report an extraordinary case of egg mimicry by a fungus, whereby the fungus gains competitor-free habitat in termite nests. Brown fungal balls, called 'termite balls', are frequently found in egg piles of Reticulitermes termites. Phylogenetic analysis illustrated that termite-ball fungi isolated from different hosts (Reticulitermes speratus, Reticulitermes flavipes and Reticulitermes virginicus) were all very similar, with no significant molecular differences among host species or geographical locations. I found no significant effect of termite balls on egg survivorship. The termite-ball fungus rarely kills termite eggs in natural colonies. Even a termite species (Reticulitermes okinawanus) with no natural association with the fungus tended termite balls along with its eggs when it was experimentally provided with termite balls. Dummy-egg bioassays using glass beads showed that both morphological and chemical camouflage were necessary to induce tending by termites. Termites almost exclusively tended termite balls with diameters that exactly matched their egg size. Moreover, scanning electron microscopic observations revealed sophisticated mimicry of the smooth surface texture of eggs. These results provide clear evidence that this interaction is beneficial only for the fungus, i.e. termite balls parasitically mimic termite eggs.

Antifungal Activity of Thapsia villosa Essential Oil against Candida, Cryptococcus, Malassezia, Aspergillus and Dermatophyte Species

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Eugénia Pinto

2017-09-01

Full Text Available The composition of the essential oil (EO of Thapsia villosa (Apiaceae, isolated by hydrodistillation from the plant’s aerial parts, was analysed by GC and GC-MS. Antifungal activity of the EO and its main components, limonene (57.5% and methyleugenol (35.9%, were evaluated against clinically relevant yeasts (Candida spp., Cryptococcus neoformans and Malassezia furfur and moulds (Aspergillus spp. and dermatophytes. Minimum inhibitory concentrations (MICs were measured according to the broth macrodilution protocols by Clinical and Laboratory Standards Institute (CLSI. The EO, limonene and methyleugenol displayed low MIC and MFC (minimum fungicidal concentration values against Candida spp., Cryptococcus neoformans, dermatophytes, and Aspergillus spp. Regarding Candida species, an inhibition of yeast–mycelium transition was demonstrated at sub-inhibitory concentrations of the EO (MIC/128; 0.01 μL/mL and their major compounds in Candida albicans. Fluconazole does not show this activity, and the combination with low concentrations of EO could associate a supplementary target for the antifungal activity. The association of fluconazole with T. villosa oil does not show antagonism, but the combination limonene/fluconazole displays synergism. The fungistatic and fungicidal activities revealed by T. villosa EO and its main compounds, associated with their low haemolytic activity, confirm their potential antimicrobial interest against fungal species often associated with human mycoses.

Arabidopsis flower specific defense gene expression patterns affect resistance to pathogens

KAUST Repository

Ederli, Luisa

2015-02-20

We investigated whether the Arabidopsis flower evolved protective measures to increase reproductive success. Firstly, analyses of available transcriptome data show that the most highly expressed transcripts in the closed sepal (stage 12) are enriched in genes with roles in responses to chemical stimuli and cellular metabolic processes. At stage 15, there is enrichment in transcripts with a role in responses to biotic stimuli. Comparative analyses between the sepal and petal in the open flower mark an over-representation of transcripts with a role in responses to stress and catalytic activity. Secondly, the content of the biotic defense-associated phytohormone salicylic acid (SA) in sepals and petals is significantly higher than in leaves. To understand whether the high levels of stress responsive transcripts and the higher SA content affect defense, wild-type plants (Col-0) and transgenic plants defective in SA accumulation (nahG) were challenged with the biotrophic fungus Golovinomyces cichoracearum, the causal agent of powdery mildew, and the necrotrophic fungus Botrytis cinerea. NahG leaves were more sensitive than those of Col-0, suggesting that in leaves SA has a role in the defense against biotrophs. In contrast, sepals and petals of both genotypes were resistant to G. cichoracearum, indicating that in the flower, resistance to the biotrophic pathogen is not critically dependent on SA, but likely dependent on the up-regulation of stress-responsive genes. Since sepals and petals of both genotypes are equally susceptible to B. cinerea, we conclude that neither stress-response genes nor increased SA accumulation offers protection against the necrotrophic pathogen. These results are interpreted in the light of the distinctive role of the flower and we propose that in the early stages, the sepal may act as a chemical defense barrier of the developing reproductive structures against biotrophic pathogens.

Multilocus sequence typing analysis reveals that Cryptococcus neoformans var. neoformans is a recombinant population.

Science.gov (United States)

Cogliati, Massimo; Zani, Alberto; Rickerts, Volker; McCormick, Ilka; Desnos-Ollivier, Marie; Velegraki, Aristea; Escandon, Patricia; Ichikawa, Tomoe; Ikeda, Reiko; Bienvenu, Anne-Lise; Tintelnot, Kathrin; Tore, Okan; Akcaglar, Sevim; Lockhart, Shawn; Tortorano, Anna Maria; Varma, Ashok

2016-02-01

Cryptococcus neoformans var. neoformans (serotype D) represents about 30% of the clinical isolates in Europe and is present less frequently in the other continents. It is the prevalent etiological agent in primary cutaneous cryptococcosis as well as in cryptococcal skin lesions of disseminated cryptococcosis. Very little is known about the genotypic diversity of this Cryptococcus subtype. The aim of this study was to investigate the genotypic diversity among a set of clinical and environmental C. neoformans var. neoformans isolates and to evaluate the relationship between genotypes, geographical origin and clinical manifestations. A total of 83 globally collected C. neoformans var. neoformans isolates from Italy, Germany, France, Belgium, Denmark, Greece, Turkey, Thailand, Japan, Colombia, and the USA, recovered from different sources (primary and secondary cutaneous cryptococcosis, disseminated cryptococcosis, the environment, and animals), were included in the study. All isolates were confirmed to belong to genotype VNIV by molecular typing and they were further investigated by MLST analysis. Maximum likelihood phylogenetic as well as network analysis strongly suggested the existence of a recombinant rather than a clonal population structure. Geographical origin and source of isolation were not correlated with a specific MLST genotype. The comparison with a set of outgroup C. neoformans var. grubii isolates provided clear evidence that the two varieties have different population structures. Copyright © 2016 Elsevier Inc. All rights reserved.

Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identity novel genes expressed during vegetative infectious, and repoductive growth

NARCIS (Netherlands)

Bluhm, B.H.; Lindquist, E.; Kema, G.H.J.; Goodwin, S.B.; Dunkle, L.D.

2008-01-01

The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The

Widespread presence of the pathogenic fungus Batrachochytrium dendrobatidis in wild amphibian communities in Madagascar

Science.gov (United States)

Bletz, Molly C.; Rosa, Gonçalo M.; Andreone, Franco; Courtois, Elodie A.; Schmeller, Dirk S.; Rabibisoa, Nirhy H. C.; Rabemananjara, Falitiana C. E.; Raharivololoniaina, Liliane; Vences, Miguel; Weldon, Ché; Edmonds, Devin; Raxworthy, Christopher J.; Harris, Reid N.; Fisher, Matthew C.; Crottini, Angelica

2015-01-01

Amphibian chytridiomycosis, an emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), has been a significant driver of amphibian declines. While globally widespread, Bd had not yet been reported from within Madagascar. We document surveys conducted across the country between 2005 and 2014, showing Bd's first record in 2010. Subsequently, Bd was detected in multiple areas, with prevalence reaching up to 100%. Detection of Bd appears to be associated with mid to high elevation sites and to have a seasonal pattern, with greater detectability during the dry season. Lineage-based PCR was performed on a subset of samples. While some did not amplify with any lineage probe, when a positive signal was observed, samples were most similar to the Global Panzootic Lineage (BdGPL). These results may suggest that Bd arrived recently, but do not exclude the existence of a previously undetected endemic Bd genotype. Representatives of all native anuran families have tested Bd-positive, and exposure trials confirm infection by Bd is possible. Bd's presence could pose significant threats to Madagascar's unique “megadiverse” amphibians. PMID:25719857

First report on Cryptococcus neoformans in pigeon excreta from public and residential locations in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil.

Science.gov (United States)

Takahara, Doracilde Terumi; Lazéra, Márcia dos Santos; Wanke, Bodo; Trilles, Luciana; Dutra, Valéria; Paula, Daphine Ariadne Jesus de; Nakazato, Luciano; Anzai, Mariana Caselli; Leite Júnior, Diniz Pereira; Paula, Claudete Rodrigues; Hahn, Rosane Christine

2013-01-01

Cryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformans was evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5), churches (n = 4), educational institutions (n = 3), health units (n = 8), open areas covered with asbestos (n = 4), residences (n = 23), factory (n = 1) and a prison (n = 1). Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA). Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6%) samples corresponding to six (12.2%) locations. Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

Mucormycosis (Mucor fungus ball) of the maxillary sinus.

Science.gov (United States)

Cho, Hang Sun; Yang, Hoon Shik; Kim, Kyung Soo

2014-01-01

A fungus ball is an extramucosal fungal proliferation that completely fills one or more paranasal sinuses and usually occurs as a unilateral infection. It is mainly caused by Aspergillus spp in an immunocompetent host, but some cases of paranasal fungal balls reportedly have been caused by Mucor spp. A Mucor fungus ball is usually found in the maxillary sinus and/or the sphenoid sinus and may be black in color. Patients with mucormycosis, or a Mucor fungal ball infection, usually present with facial pain or headache. On computed tomography, there are no pathognomonic findings that are conclusive for a diagnosis of mucormycosis. In this article we report a case of mucormycosis in a 56-year-old woman and provide a comprehensive review of the literature on the "Mucor fungus ball." To the best of our knowledge, 5 case reports (8 patients) have been published in which the fungus ball was thought to be caused by Mucor spp.

Solubilization of diabase and phonolite dust by filamentous fungus

Directory of Open Access Journals (Sweden)

Juliana Andréia Vrba Brandão

2014-10-01

Full Text Available The objective of this study was to evaluate the effect of the fungus Aspergillus niger strain CCT4355 in the release of nutrients contained in two types of rock powder (diabase and phonolite by means of in vitro solubilization trials. The experimental design was completely randomized in a 5 x 4 factorial design with three replications. It was evaluated five treatments (phonolite dust + culture medium; phonolite dust + fungus + culture medium; diabase powder + culture medium; diabase powder + fungus + culture medium and fungus + culture medium and four sampling dates (0, 10, 20 and 30 days. Rock dust (0.4% w/v was added to 125 mL Erlenmeyer flasks containing 50 mL of liquid culture medium adapted to A. niger. The flasks were incubated at 30°C for 30 days, and analysis of pH (in water, titratable acidity, and concentrations of soluble potassium, calcium, magnesium, zinc, iron and manganese were made. The fungus A. niger was able to produce organic acids that solubilized ions. This result indicates its potential to alter minerals contained in rock dust, with the ability to interact in different ways with the nutrients. A significant increase in the amount of K was found in the treatment with phonolite dust in the presence of the fungus. The strain CCT4355 of A. niger can solubilize minerals contained in these rocks dust.

Transcriptional control of drug resistance, virulence and immune system evasion in pathogenic fungi: a cross-species comparison.

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Pedro Pais

2016-10-01

Full Text Available Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis and Candida tropicalis. Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed.

Transcriptional Control of Drug Resistance, Virulence and Immune System Evasion in Pathogenic Fungi: A Cross-Species Comparison.

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Pais, Pedro; Costa, Catarina; Cavalheiro, Mafalda; Romão, Daniela; Teixeira, Miguel C

2016-01-01

Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis , and Candida tropicalis . Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed.

Draft Genome Sequences of Human Pathogenic Fungus Geomyces pannorum Sensu Lato and Bat White Nose Syndrome Pathogen Geomyces (Pseudogymnoascus) destructans

OpenAIRE

Chibucos, Marcus C.; Crabtree, Jonathan; Nagaraj, Sushma; Chaturvedi, Sudha; Chaturvedi, Vishnu

2013-01-01

We report the draft genome sequences of Geomyces pannorum sensu lato and Geomyces (Pseudogymnoascus) destructans. G.?pannorum has a larger proteome than G.?destructans, containing more proteins with ascribed enzymatic functions. This dichotomy in the genomes of related psychrophilic fungi is a valuable target for defining their distinct saprobic and pathogenic attributes.

Hypovirulence of the phytopathogenic fungus Botryosphaeria dothidea: association with a coinfecting chrysovirus and a partitivirus.

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Wang, LiPing; Jiang, JingJing; Wang, YanFen; Hong, Ni; Zhang, Fangpeng; Xu, WenXing; Wang, GuoPing

2014-07-01

Botryosphaeria dothidea is an important pathogenic fungus causing fruit rot, leaf and stem ring spots and dieback, stem canker, stem death or stool mortality, and decline of pear trees. Seven double-stranded RNAs (dsRNAs; dsRNAs 1 to 7 with sizes of 3,654, 2,773, 2,597, 2,574, 1,823, 1,623, and 511 bp, respectively) were identified in an isolate of B. dothidea exhibiting attenuated growth and virulence and a sectoring phenotype. Characterization of the dsRNAs revealed that they belong to two dsRNA mycoviruses. The four largest dsRNAs (dsRNAs 1 to 4) are the genomic components of a novel member of the family Chrysoviridae (tentatively designated Botryosphaeria dothidea chrysovirus 1 [BdCV1]), a view supported by the morphology of the virions and phylogenetic analysis of the putative RNA-dependent RNA polymerases (RdRps). Two other dsRNAs (dsRNAs 5 and 6) are the genomic components of a novel member of the family Partitiviridae (tentatively designated Botryosphaeria dothidea partitivirus 1 [BdPV1]), which is placed in a clade distinct from other established partitivirus genera on the basis of the phylogenetic analysis of its RdRp. The smallest dsRNA, dsRNA7, seems to be a noncoding satellite RNA of BdPV1 on the basis of the conservation of its terminal sequences in BdPV1 genomic segments and its cosegregation with BdPV1 after horizontal transmission. This is the first report of a chrysovirus and a partitivirus infecting B. dothidea and of a chrysovirus associated with the hypovirulence of a phytopathogenic fungus. Our studies identified and characterized two novel mycoviruses, Botryosphaeria dothidea chrysovirus 1 (BdCV1) and Botryosphaeria dothidea partitivirus 1 (BdPV1), associated with the hypovirulence of an important fungus pathogenic to fruit trees. This is the first report of a chrysovirus and a partitivirus infecting B. dothidea and of a chrysovirus associated with the hypovirulence of a phytopathogenic fungus. BdCV1 appears to be a good candidate for the

Draft Genome Sequences of Human Pathogenic Fungus Geomyces pannorum Sensu Lato and Bat White Nose Syndrome Pathogen Geomyces (Pseudogymnoascus) destructans.

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Chibucos, Marcus C; Crabtree, Jonathan; Nagaraj, Sushma; Chaturvedi, Sudha; Chaturvedi, Vishnu

2013-12-19

We report the draft genome sequences of Geomyces pannorum sensu lato and Geomyces (Pseudogymnoascus) destructans. G. pannorum has a larger proteome than G. destructans, containing more proteins with ascribed enzymatic functions. This dichotomy in the genomes of related psychrophilic fungi is a valuable target for defining their distinct saprobic and pathogenic attributes.

Thailandins A and B, New Polyene Macrolactone Compounds Isolated from Actinokineospora bangkokensis Strain 44EHW(T), Possessing Antifungal Activity against Anthracnose Fungi and Pathogenic Yeasts.

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Intra, Bungonsiri; Greule, Anja; Bechthold, Andreas; Euanorasetr, Jirayut; Paululat, Thomas; Panbangred, Watanalai

2016-06-29

Two new polyene macrolactone antibiotics, thailandins A, 1, and B, 2, were isolated from the fermentation broth of rhizosphere soil-associated Actinokineospora bangkokensis strain 44EHW(T). The new compounds from this strain were purified using semipreparative HPLC and Sephadex LH-20 gel filtration while following an antifungal activity guided fractionation. Their structures were elucidated through spectroscopic techniques including UV, HR-ESI-MS, and NMR. These compounds demonstrated broad spectrum antifungal activity against fungi causing anthracnose disease (Colletotrichum gloeosporioides DoA d0762, Colletotrichum gloeosporiodes DoA c1060, and Colletotrichum capsici DoA c1511) as well as pathogenic yeasts (Candida albicans MT 2013/1, Candida parasilopsis DKMU 434, and Cryptococcus neoformans MT 2013/2) with minimum inhibitory concentrations ranging between 16 and 32 μg/mL. This is the first report of polyene antibiotics produced by Actinokineospora species as bioactive compounds against anthracnose fungi and pathogenic yeast strains.

Two cation transporters Ena1 and Nha1 cooperatively modulate ion homeostasis, antifungal drug resistance, and virulence of Cryptococcus neoformans via the HOG pathway

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Jung, Kwang-Woo; Strain, Anna K; Nielsen, Kirsten; Jung, Kwang-Hwan; Bahn, Yong-Sun

2012-01-01

Maintenance of cation homeostasis is essential for survival of all living organisms in their biological niches. It is also important for the survival of human pathogenic fungi in the host, where cation concentrations and pH will vary depending on different anatomical sites. However, the exact role of diverse cation transporters and ion channels in virulence of fungal pathogens remains elusive. In this study we functionally characterized ENA1 and NHA1, encoding a putative Na+/ATPase and Na+/H+ antiporter, respectively, in Cryptococcus neoformans, a basidiomycete fungal pathogen which causes fatal meningoencephalitis. Expression of NHA1 and ENA1 is induced in response to salt and osmotic shock mainly in a Hog1-dependent manner. Phenotypic analysis of the ena1, nha1, and ena1 nha1 mutants revealed that Ena1 controls cellular levels of toxic cations, such as Na+ and Li+ whereas both Ena1 and Nha1 are important for controlling less toxic K+ ions. Under alkaline conditions, Ena1 was highly induced and required for growth in the presence of low levels of Na+ or K+ salt and Nha1 played a role in survival under K+ stress. In contrast, Nha1, but not Ena1, was essential for survival at acidic conditions (pH 4.5) under high K+ stress. In addition, Ena1 and Nha1 were required for maintenance of plasma membrane potential and stability, which appeared to modulate antifungal drug susceptibility. Perturbation of ENA1 and NHA1 enhanced capsule production and melanin synthesis. However, Nha1 was dispensable for virulence of C. neoformans although Ena1 was essential. In conclusion, Ena1 and Nha1 play redundant and discrete roles in cation homeostasis, pH regulation, membrane potential, and virulence in C. neoformans, suggesting that these transporters could be novel antifungal drug targets for treatment of cryptococcosis. PMID:22343280

Secretome Analysis Identifies Potential Pathogenicity/Virulence Factors of Tilletia indica, a Quarantined Fungal Pathogen Inciting Karnal Bunt Disease in Wheat.

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Pandey, Vishakha; Singh, Manoj; Pandey, Dinesh; Marla, Soma; Kumar, Anil

2018-04-01

Tilletia indica is a smut fungus that incites Karnal bunt in wheat. It has been considered as quarantine pest in more than 70 countries. Despite its quarantine significance, there is meager knowledge regarding the molecular mechanisms of disease pathogenesis. Moreover, various disease management strategies have proven futile. Development of effective disease management strategy requires identification of pathogenicity/virulence factors. With this aim, the present study was conducted to compare the secretomes of T. indica isolates, that is, highly (TiK) and low (TiP) virulent isolates. About 120 and 95 protein spots were detected reproducibly in TiK and TiP secretome gel images. Nineteen protein spots, which were consistently observed as upregulated/differential in the secretome of TiK isolate, were selected for their identification by MALDI-TOF/TOF. Identified proteins exhibited homology with fungal proteins playing important role in fungal adhesion, penetration, invasion, protection against host-derived reactive oxygen species, production of virulence factors, cellular signaling, and degradation of host cell wall proteins and antifungal proteins. These results were complemented with T. indica genome sequence leading to identification of candidate pathogenicity/virulence factors homologs that were further subjected to sequence- and structure-based functional annotation. Thus, present study reports the first comparative secretome analysis of T. indica for identification of pathogenicity/virulence factors. This would provide insights into pathogenic mechanisms of T. indica and aid in devising effective disease management strategies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnesium Ion Acts as a Signal for Capsule Induction in Cryptococcus neoformans.

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Rathore, Sudarshan S; Raman, Thiagarajan; Ramakrishnan, Jayapradha

2016-01-01

Cryptococcal meningitis caused by Cryptococcus neoformans, is a common opportunistic neural infection in immunocompromised individuals. Cryptococcus meningitis is associated with fungal burden with larger capsule size in cerebrospinal fluid (CSF). To understand the role of CSF constituents in capsule enlargement, we have evaluated the effect of artificial CSF on capsule induction in comparison with various other capsule inducing media. Two different strains of C. neoformans, an environmental and a clinical isolates were used in the present study. While comparing the various capsule inducing media for the two different strains of C. neoformans, it was observed that the capsule growth was significantly increased when grown in artificial CSF at pH 5.5, temperature 34°C for ATCC C. neoformans and 37°C for Clinical C. neoformans and with an incubation period of 72 h. In addition, artificial CSF supports biofilm formation in C. neoformans. While investigating the individual components of artificial CSF, we found that Mg(2+) ions influence the capsule growth in both environmental and clinical strains of C. neoformans. To confirm our results we studied the expression of four major CAP genes namely, CAP10, CAP59, CAP60, and CAP64 in various capsule inducing media and in different concentrations of Mg(2+) and Ca(2+). Our results on gene expression suggest that, Mg(2+) does have an effect on CAP gene expression, which are important for capsule biosynthesis and virulence. Our findings on the role of Mg(2+) ion as a signal for capsule induction will promote a way to elucidate the control mechanisms for capsule biosynthesis in C. neoformans.

Detection of Cryptococcus neoformans DNA in Tissue Samples by Nested and Real-Time PCR Assays

OpenAIRE

Bialek, Ralf; Weiss, Michael; Bekure-Nemariam, Kubrom; Najvar, Laura K.; Alberdi, Maria B.; Graybill, John R.; Reischl, Udo

2002-01-01

Two PCR protocols targeting the 18S rRNA gene of Cryptococcus neoformans were established, compared, and evaluated in murine cryptococcal meningitis. One protocol was designed as a nested PCR to be performed in conventional block thermal cyclers. The other protocol was designed as a quantitative single-round PCR adapted to LightCycler technology. One hundred brain homogenates and dilutions originating from 20 ICR mice treated with different azoles were examined. A fungal burden of 3 × 101 to ...

MoDUO1, a Duo1-like gene, is required for full virulence of the rice blast fungus Magnaporthe oryzae.

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Peng, Haowen; Feng, Youjun; Zhu, Xiaohui; Lan, Xiuwan; Tang, Mei; Wang, Jinzi; Dong, Haitao; Chen, Baoshan

2011-12-01

Duo1, a major component of the Dam1 complex which has been found in two species of yeast (the budding yeast Saccharomyces cerevisae and the fission yeast Schizosaccharomyces pombe), is involved in mitosis-related chromosome segregation, while its relevance to pathogenicity in filamentous fungi remains unclear. This report elucidated this very fact in the case of the rice blast fungus Magnaporthe oryzae. A gene designated MoDUO1 that encodes a Duo1-like homolog (MoDuo1) was discovered in the M. oryzae genome. Two types of MoDUO1 mutants were obtained using genetic approaches of Agrobacterium-mediated gene disruption and homologous recombination. Both disruption and deletion of MoDUO1 can exert profound effects on the formation pattern of conidiophores and conidial morphology, such as abnormal nucleic numbers in conidia and delayed extension of infectious hyphae. Intriguingly, plant infection assays demonstrated that inactivation of MoDUO1 significantly attenuates the virulence in its natural host rice leaves, and functional complementation can restore it. Subcellular localization assays showed that MoDuo1 is mainly distributed in the cytosol of fungal cells. Proteomics-based investigation revealed that the expression of four mitosis-related proteins is shut down in the MoDUO1 mutant, suggesting that MoDuo1 may have a function in mitosis. In light of the fact that Duo1 orthologs are widespread in plant and human fungal pathogens, our finding may represent a common mechanism underlying fungal virulence. To the best of our knowledge, this is the first example of linking a Duo1-like homolog to the pathogenesis of a pathogenic fungus, which might provide clues to additional studies on the role of Dam1 complex in M. oryzae and its interaction with rice.

Isolation and identification of iron ore-solubilising fungus

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Damase Khasa

2010-09-01

Full Text Available Potential mineral-solubilising fungi were successfully isolated from the surfaces of iron ore minerals. Four isolates were obtained and identified by molecular and phylogenetic methods as close relatives of three different genera, namely Penicillium (for isolate FO, Alternaria (for isolates SFC2 and KFC1 and Epicoccum (for isolate SFC2B. The use of tricalcium phosphate (Ca₃(PO₄₂in phosphate-solubilising experiments confirmed isolate FO as the only phosphate solubiliser among the isolated fungi. The bioleaching capabilities of both the fungus and its spent liquid medium were tested and compared using two types of iron ore materials, conglomerate and shale, from the Sishen Iron Ore Mine as sources of potassium (K and phosphorus (P. The spent liquid medium removed more K (a maximum of 32.94% removal, from conglomerate, than the fungus (a maximum of 21.36% removal, from shale. However, the fungus removed more P (a maximum of 58.33% removal, from conglomerate than the spent liquid medium (a maximum of 29.25% removal, from conglomerate. The results also indicated a potential relationship between the removal of K or P and the production of organic acids by the fungus. A high production of gluconic acid could be related to the ability of the fungus to reduce K and P. Acetic, citric and maleic acids were also produced by the fungus, but in lower quantities. In addition, particle size and iron ore type were also shown to have significant effects on the removal of potassium and phosphorus from the iron ore minerals. We therefore conclude that the spent liquid medium from the fungal isolate FO can potentially be used for biobeneficiation of iron ore minerals.

Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome.

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Warnecke, Lisa; Turner, James M; Bollinger, Trent K; Lorch, Jeffrey M; Misra, Vikram; Cryan, Paul M; Wibbelt, Gudrun; Blehert, David S; Willis, Craig K R

2012-05-01

White-nose syndrome (WNS) is an emerging disease of hibernating bats associated with cutaneous infection by the fungus Geomyces destructans (Gd), and responsible for devastating declines of bat populations in eastern North America. Affected bats appear emaciated and one hypothesis is that they spend too much time out of torpor during hibernation, depleting vital fat reserves required to survive the winter. The fungus has also been found at low levels on bats throughout Europe but without mass mortality. This finding suggests that Gd is either native to both continents but has been rendered more pathogenic in North America by mutation or environmental change, or that it recently arrived in North America as an invader from Europe. Thus, a causal link between Gd and mortality has not been established and the reason for its high pathogenicity in North America is unknown. Here we show that experimental inoculation with either North American or European isolates of Gd causes WNS and mortality in the North American bat, Myotis lucifugus. In contrast to control bats, individuals inoculated with either isolate of Gd developed cutaneous infections diagnostic of WNS, exhibited a progressive increase in the frequency of arousals from torpor during hibernation, and were emaciated after 3-4 mo. Our results demonstrate that altered torpor-arousal cycles underlie mortality from WNS and provide direct evidence that Gd is a novel pathogen to North America from Europe.

Pathogen-Reactive T Helper Cell Analysis in the Pig

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Friederike Ebner

2017-05-01

Full Text Available There is growing interest in studying host–pathogen interactions in human-relevant large animal models such as the pig. Despite the progress in developing immunological reagents for porcine T cell research, there is an urgent need to directly assess pathogen-specific T cells—an extremely rare population of cells, but of upmost importance in orchestrating the host immune response to a given pathogen. Here, we established that the activation marker CD154 (CD40L, known from human and mouse studies, identifies also porcine antigen-reactive CD4+ T lymphocytes. CD154 expression was upregulated early after antigen encounter and CD4+CD154+ antigen-reactive T cells coexpressed cytokines. Antigen-induced expansion and autologous restimulation enabled a time- and dose-resolved analysis of CD154 regulation and a significantly increased resolution in phenotypic profiling of antigen-responsive cells. CD154 expression identified T cells responding to staphylococcal Enterotoxin B superantigen stimulation as well as T cells responding to the fungus Candida albicans and T cells specific for a highly prevalent intestinal parasite, the nematode Ascaris suum during acute and trickle infection. Antigen-reactive T cells were further detected after immunization of pigs with a single recombinant bacterial antigen of Streptococcus suis only. Thus, our study offers new ways to study antigen-specific T lymphocytes in the pig and their contribution to host–pathogen interactions.

Pathogenicity of Neonectria fuckeliana on Norway Spruce Clones in Sweden and Potential Management Strategies

OpenAIRE

Martin Pettersson; Venche Talgø; John Frampton; Bo Karlsson; Jonas Rönnberg

2018-01-01

The fungus Neonectria fuckeliana has become an increasing problem on Norway spruce (Picea abies) in the Nordic countries during recent years. Canker wounds caused by the pathogen reduce timber quality and top-dieback is a problem for the Christmas tree industry. In this study, four inoculation trials were conducted to examine the ability of N. fuckeliana to cause disease on young Norway spruce plants and determine how different wound types would affect the occurrence and severity of the disea...

Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus.

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Zhu, Lin; Zhu, Jian; Liu, Zhixue; Wang, Zhengyi; Zhou, Cheng; Wang, Hong

2017-09-26

Magnaporthe oryzae is a devastating plant pathogen, which has a detrimental impact on rice production worldwide. Despite its agronomical importance, some newly-emerging pathotypes often overcome race-specific disease resistance rapidly. It is thus desirable to develop a novel strategy for the long-lasting resistance of rice plants to ever-changing fungal pathogens. Brome mosaic virus (BMV)-induced RNA interference (RNAi) has emerged as a useful tool to study host-resistance genes for rice blast protection. Planta-generated silencing of targeted genes inside biotrophic pathogens can be achieved by expression of M. oryzae -derived gene fragments in the BMV-mediated gene silencing system, a technique termed host-induced gene silencing (HIGS). In this study, the effectiveness of BMV-mediated HIGS in M. oryzae was examined by targeting three predicted pathogenicity genes, MoABC1, MoMAC1 and MoPMK1 . Systemic generation of fungal gene-specific small interfering RNA (siRNA) molecules induced by inoculation of BMV viral vectors inhibited disease development and reduced the transcription of targeted fungal genes after subsequent M. oryzae inoculation. Combined introduction of fungal gene sequences in sense and antisense orientation mediated by the BMV silencing vectors significantly enhanced the efficiency of this host-generated trans-specific RNAi, implying that these fungal genes played crucial roles in pathogenicity. Collectively, our results indicated that BMV-HIGS system was a great strategy for protecting host plants against the invasion of pathogenic fungi.

Biodiesel production from yeast Cryptococcus sp. using Jerusalem artichoke.

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Sung, Mina; Seo, Yeong Hwan; Han, Shin; Han, Jong-In

2014-03-01

Jerusalem artichoke was investigated as a cheap substrate for the heterotrophic production using a lab yeast strain Cryptococcus sp. Using Response Surface Method, 54.0% of fructose yield was achieved at 12% of dried Jerusalem artichoke powder, 0.57% of nitric acid concentration, 117°C of reaction temperature, and 49min of reaction time. At this optimal condition, nitric acid showed the best catalytic activity toward inulin hydrolysis and also the resulting fructose hydrolyte supported the highest microbial growth compared with other acids. In addition, lipid productivity of 1.73g/L/d was achieved, which is higher than a defined medium using pure fructose as a substrate. Lipid quality was also found to be generally satisfactory as a feedstock for fuel, demonstrating Jerusalem artichoke could indeed be a good and cheap option for the purpose of biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Resting spore formation of aphid-pathogenic fungus Pandora nouryi depends on the concentration of infective inoculum.

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Huang, Zhi-Hong; Feng, Ming-Guang

2008-07-01

Resting spore formation of some aphid-pathogenic Entomophthorales is important for the seasonal pattern of their prevalence and survival but this process is poorly understood. To explore the possible mechanism involved in the process, Pandora nouryi (obligate aphid pathogen) interacted with green peach aphid Myzus persicae on cabbage leaves under favourable conditions. Host nymphs showered with primary conidia of an isolate (LC(50): 0.9-6.7 conidia mm(-2) 4-7 days post shower) from air captures in the low-latitude plateau of China produced resting spores (azygospores), primary conidia or both spore types. Surprisingly, the proportion of mycosed cadavers forming resting spores (P(CFRS)) increased sharply within the concentrations (C) of 28-240 conidia mm(-2), retained high levels at 240-1760, but was zero or extremely low at 0.3-16. The P(CFRS)-C relationship fit well the logistic equation P(CFRS) = 0.6774/[1 + exp(3.1229-0.0270C)] (r(2) = 0.975). This clarified for the first time the dependence of in vivo resting spore formation of P. nouryi upon the concentration of infective inoculum. A hypothesis is thus proposed that some sort of biochemical signals may exist in the host-pathogen interaction so that the fungal pathogen perceives the signals for prompt response to forthcoming host-density changes by either producing conidia for infecting available hosts or forming resting spores for surviving host absence in situ.

Selection of reference genes for expression analysis in the entomophthoralean fungus Pandora neoaphidis.

Science.gov (United States)

Chen, Chun; Xie, Tingna; Ye, Sudan; Jensen, Annette Bruun; Eilenberg, Jørgen

2016-01-01

The selection of suitable reference genes is crucial for accurate quantification of gene expression and can add to our understanding of host-pathogen interactions. To identify suitable reference genes in Pandora neoaphidis, an obligate aphid pathogenic fungus, the expression of three traditional candidate genes including 18S rRNA(18S), 28S rRNA(28S) and elongation factor 1 alpha-like protein (EF1), were measured by quantitative polymerase chain reaction at different developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae), and under different nutritional conditions. We calculated the expression stability of candidate reference genes using four algorithms including geNorm, NormFinder, BestKeeper and Delta Ct. The analysis results revealed that the comprehensive ranking of candidate reference genes from the most stable to the least stable was 18S (1.189), 28S (1.414) and EF1 (3). The 18S was, therefore, the most suitable reference gene for real-time RT-PCR analysis of gene expression under all conditions. These results will support further studies on gene expression in P. neoaphidis. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Selection of reference genes for expression analysis in the entomophthoralean fungus Pandora neoaphidis

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Chun Chen

2016-03-01

Full Text Available Abstract The selection of suitable reference genes is crucial for accurate quantification of gene expression and can add to our understanding of host–pathogen interactions. To identify suitable reference genes in Pandora neoaphidis, an obligate aphid pathogenic fungus, the expression of three traditional candidate genes including 18S rRNA(18S, 28S rRNA(28S and elongation factor 1 alpha-like protein (EF1, were measured by quantitative polymerase chain reaction at different developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae, and under different nutritional conditions. We calculated the expression stability of candidate reference genes using four algorithms including geNorm, NormFinder, BestKeeper and Delta Ct. The analysis results revealed that the comprehensive ranking of candidate reference genes from the most stable to the least stable was 18S (1.189, 28S (1.414 and EF1 (3. The 18S was, therefore, the most suitable reference gene for real-time RT-PCR analysis of gene expression under all conditions. These results will support further studies on gene expression in P. neoaphidis.

A constitutively expressed antifungal peptide protects Tenebrio molitor during a natural infection by the entomopathogenic fungus Beauveria bassiana.

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Maistrou, Sevasti; Paris, Véronique; Jensen, Annette B; Rolff, Jens; Meyling, Nicolai V; Zanchi, Caroline

2018-09-01

Antimicrobial peptides have been well studied in the context of bacterial infections. Antifungal peptides have received comparatively less attention. Fungal pathogens of insects and their hosts represent a unique opportunity to study host-pathogen interactions due to the million of years of co-evolution they share. In this study, we investigated role of a constitutively expressed thaumatin-like peptide with antifungal activity expressed by the mealworm beetle Tenebrio molitor, named Tenecin 3, during a natural infection with the entomopathogenic fungus Beauveria bassiana. We monitored the effect of the expression of Tenecin 3 on the survival of infected hosts as well as on the progression of the fungal infection inside the host. Finally, we tested the activity of Tenecin 3 against B. bassiana. These findings could help improving biocontrol strategies and help understanding the evolution of antifungal peptides as a defense mechanism. Copyright © 2018 Elsevier Ltd. All rights reserved.