Differential transcription of mating-type genes during sexual reproduction of natural Cordyceps sinensis / 中国中药杂志

Natural Cordyceps sinensis as an insect-fungal complex, which is developed after Ophiocordyceps sinensis infects a larva of Hepialidae family. Seventeen genotypes of O. sinensis have been identified in natural C. sinensis. This paper summarized the literature reports and GenBank database regarding occurrence and transcription of the mating-type genes of MAT1-1 and MAT1-2 idiomorphs in natural C. sinensis, in Hirsutella sinensis(GC-biased Genotype #1 of O. sinensis), to infer the mating pattern of O. sinensis in the lifecycle of natural C. sinensis. The mating-type genes and transcripts of MAT1-1 and MAT1-2 idiomorphs were identified in the metagenomes and metatranscriptomes of natural C. sinensis. However, their fungal sources are unclear because of co-colonization of several genotypes of O. sinensis and multiple fungal species in natural C. sinensis. The mating-type genes of MAT1-1 and MAT1-2 idiomorphs were differentially present in 237 H. sinensis strains, constituting the genetic control of the O. sinensis reproduction. Transcriptional control of the O. sinensis reproduction includes: differential transcription or silencing of the mating-type genes of MAT1-1 and MAT1-2 idiomorphs, and the MAT1-2-1 transcript with unspliced intron I that contains 3 stop codons. Research on the H. sinensis transcriptome demonstrated differential and complementary transcriptions of the mating-type genes of MAT1-1 and MAT1-2 idiomorphs in Strains L0106 and 1229, which may become mating partners to accomplish physiological heterothallism. The differential occurrence and transcription of the mating-type genes in H. sinensis are inconsistent with the self-fertilization hypothesis under homothallism or pseudohomothallism, but instead indicate the need of mating partners of the same H. sinensis species, either monoecious or dioecious, for physiological heterothallism, or heterospecific species for hybridization. Multiple GC-and AT-biased genotypes of O. sinensis were identified in the stroma, stromal fertile portion(densely covered with numerous ascocarps) and ascospores of natural C. sinensis. It needs to be further explored if the genome-independent O. sinensis genotypes could become mating partners to accomplish sexual reproduction. S. hepiali Strain FENG experienced differential transcription of the mating-type genes with a pattern complementary to that of H. sinensis Strain L0106. Additional evidence is needed to explore a hybridization possibility between S. hepiali and H. sinensis, whether they are able to break the interspecific reproductive isolation. Genotypes #13～14 of O. sinensis feature large DNA segment reciprocal substitutions and genetic material recombination between 2 heterospecific parental fungi, H. sinensis and an AB067719-type fungus, indicating a possibility of hybridization or parasexuality. Our analysis provides important information at the genetic and transcriptional levels regarding the mating-type gene expression and reproduction physiology of O. sinensis in the sexual life of natural C. sinensis and offers crucial reproductive physiology evidence, to assist in the design of the artificial cultivation of C. sinensis to supplement the increasing scarcity of natural resource.

A potential mating-type biomarker to detect pathogenic Ganoderma species

Aims@#The basal stem rot disease in oil palm is caused by the pathogenic Ganoderma boninense, which is infectious after mating and forming dikaryotic hyphae. This study was aimed to generate a mating-type biomarker for the detection of pathogenic Ganoderma species.@*Methodology and results@#Mating-type region of Ganoderma was amplified using polymerase chain reaction (PCR) and primers flanking the mating-type region of other basidiomycetes. Amplified fragments were sequenced and were identified as the Ganoderma pheromone receptor gene of matB locus called the gprb2 gene. Using this biomarker, the pheromone receptor gene was detected in a total of 107 pathogenic Ganoderma spp. while the gene was not detected in the non-pathogenic Ganoderma lucidum. Phylogenetic tree analyses of the gene fragment encoding the partial amino acid sequence of gprb2 showed clades of close evolutionary relationship among the 107 pathogenic Ganoderma spp. Phylogenetic analyses using deduced amino acid sequences of the Ganoderma pheromone receptor b2 gene, gprb2 with homologous pheromone receptors of other basidiomycetous fungi revealed high conservation of this pheromone receptor within their respective taxonomy.@*Conclusion, significance and impact of study@#A potential mating-type biomarker was successfully identified that could detect pathogenic Ganoderma spp. The research findings will be helpful in oil palm screening to detect pathogenic Ganoderma spp. and gain further insight into the role of the mating-type loci of Ganoderma towards its pathogenesis in causing the basal stem rot disease of oil palm.

Discovery of differential sequences for improving breeding and yield of cultivated Ophiocordyceps sinensis through ITS sequencing and phylogenetic analysis / 中国天然药物

To accelerate the breeding process of cultivated Ophiocordyceps sinensis and increase its yield, it is important to identify molecular fingerprint of dominant O. sinensis. In the present study, we collected 3 batches of industrially cultivated O. sinensis product with higher yield than the others and compared their internal transcribed spacer (ITS) sequences with the wild and the reported. The ITS sequence was obtained by bidirectional sequencing and analyzed with molecular systematics as a DNA barcode for rapid and accurate identification of wild and cultivated O. sinensis collected. The ITS sequences of O. sinensis with detailed collection loci on NCBI were downloaded to construct a phylogenetic tree together with the sequences obtained from the present study by using neighbor-joining method based on their evolution relationship. The information on collection loci was analyzed with ArcGIS 10.2 to demonstrate the geographic distribution of these samples and thus to determine the origin of the dominant samples. The results showed that all wild and cultivated samples were identified as O. sinensis and all sequences were divided into seven phylogenetic groups in the tree. Those groups were precisely distributed on the map and the process of their system evolution was clearly presented. The three cultivated samples were clustered into two dominant groups, showing the correlation between the industrially cultivated samples and the dominant wild samples, which can provide references for its optimized breeding in the future.

Discovery of differential sequences for improving breeding and yield of cultivated Ophiocordyceps sinensis through ITS sequencing and phylogenetic analysis / 中国天然药物

To accelerate the breeding process of cultivated Ophiocordyceps sinensis and increase its yield, it is important to identify molecular fingerprint of dominant O. sinensis. In the present study, we collected 3 batches of industrially cultivated O. sinensis product with higher yield than the others and compared their internal transcribed spacer (ITS) sequences with the wild and the reported. The ITS sequence was obtained by bidirectional sequencing and analyzed with molecular systematics as a DNA barcode for rapid and accurate identification of wild and cultivated O. sinensis collected. The ITS sequences of O. sinensis with detailed collection loci on NCBI were downloaded to construct a phylogenetic tree together with the sequences obtained from the present study by using neighbor-joining method based on their evolution relationship. The information on collection loci was analyzed with ArcGIS 10.2 to demonstrate the geographic distribution of these samples and thus to determine the origin of the dominant samples. The results showed that all wild and cultivated samples were identified as O. sinensis and all sequences were divided into seven phylogenetic groups in the tree. Those groups were precisely distributed on the map and the process of their system evolution was clearly presented. The three cultivated samples were clustered into two dominant groups, showing the correlation between the industrially cultivated samples and the dominant wild samples, which can provide references for its optimized breeding in the future.

First isolation of cryptococcus neoformans genotype VNI MAT-alpha from wood hollow trunks of hymenaea courbaril

Cryptococcal infection is transmitted by the inhalation of Cryptococcus spp. propagules. Information about the Cryptococcus species inhabiting plants might be clinically relevant due to the epidemiological role of these habitats as possible sources of human infection. The aim of this study was to increase the knowledge about the environmental occurrence of cryptococcosis agents. Hollow tree vegetal debris of nine plant species was sampled quarterly over a 12-month period. Melanized colonies were screened for Cryptococcus neoformans and C. gattii by biochemical tests, followed by URA5-RFLP molecular analysis, M13 fingerprinting assays, and mating-typing with the specific a and α primers. The susceptibility to fluconazole of all of the confirmed species colonies was determined using the AFST-EUCAST broth dilution method. We found that the typical Brazilian flora tree Hymenaea courbaril yielded a high cryptococcal burden (median, 10(2) CFU/g) during the summer, autumn and winter seasons. C. neoformans VNI molecular type MAT alpha was identified in all of the samples. The fingerprinting analyses showed great molecular variability with no correlation with the susceptibility profile to fluconazole (MIC range 4 to ≥64 mg/l). To our knowledge, this study is the first describing the association between C. neoformans and Hymenaea courbaril. These observations extend the known geographic distribution of and substantiate a new urban environmental niche for C. neoformans and also emphasize the genetic diversity of the environmental C. neoformans VNI molecular type isolates.

Mating Type Analysis of Dermatophytes using Mating Type Gene / 대한의진균학회지

BACKGROUND: Traditionally, mating types of dermatophytes had been identified by mating experiments. It took a long time and there were many limitations. Recently, we can figure out the fungal mating types using molecular mating type analysis by detecting mating type (MAT) genes. The mating type (+) specific gene of the high-mobility-group (HMG) DNA binding domain and the mating type (-) specific gene of alpha-box were found in Arthroderma simii and A. vanbreuseghemii. OBJECTIVE: We applied this molecular mating type analysis to strains of Trichophyton interdigitale, T. rubrum, Microsporum canis in Korea and compared these results with previous reports. METHODS: Thirty-four strains of T. interdigitale (12 granular types, 9 powdery types, 8 purple-red types, 5 cottony types), 5 strains of T. rubrum, and 5 strains of M. canis were examined. We analyzed ribosomal RNA internal transcribed space 1, 4 sequencing of T. interdigitale subtypes and investigated the mating type of dermatophytes using alpha-box gene and HMG gene primers. RESULTS: Among 12 strains of granular type of T. interdigitale, 9 strains were type (-) and other 3 strains were type (+). All of them were zoophilic. All strains of powdery, purple-red and cottony types of T. interdigitale were type (+) and anthropophilic. In T. rubrum and M. canis, all strains were type (-). These results were matched with previously reported studies. CONCLUSION: The molecular mating type analysis of dermatophytes was quicker method than conventional mating experiments. Moreover, MAT genes are highly conserved even in apparently asexual fungi. The results were well matched with previous reports with traditional mating tests.

Genotyping of the MTL loci and susceptibility to two antifungal agents of Candida glabrata clinical isolates

The opportunistic fungal pathogen Candida glabrata is the second most common isolate from bloodstream infections worldwide and is naturally less susceptible to the antifungal drug fluconazole than other Candida species. C. glabrata is a haploid yeast that contains three mating-type like loci (MTL), although no sexual cycle has been described. Strains containing both types of mating information at the MTL1 locus are found in clinical isolates, but it is thought that strains containing type a information are more common. Here we investigated if a particular combination of mating type information at each MTLlocus is more prevalent in clinical isolates from hospitalized patients in Mexico and if there is a correlation between mating information and resistance to fluconazole and 5-fluorocytosine. We found that while both types of information at MTL1 are equally represented in a collection of 64 clinical isolates, the vast majority of isolates contain a-type information at MTL2 and α-type at MTL3. We also found no correlation of the particular combination of mating type information at the three MTL loci and resistance to fluconazole.

The Pneumocystis life cycle

First recognised as "schizonts" of Trypanosoma cruzi, Pneumocystis organisms are now considered as part of an early-diverging lineage of Ascomycetes. As no robust long-term culture model is available, most data on the Pneumocystis cell cycle have stemmed from ultrastructural images of infected mammalian lungs. Although most fungi developing in animals do not complete a sexual cycle in vivo, Pneumocystis species constitute one of a few exceptions. Recently, the molecular identification of several key players in the fungal mating pathway has provided further evidence for the existence of conjugation and meiosis in Pneumocystisorganisms. Dynamic follow-up of stage-to-stage transition as well as studies of stage-specific proteins and/or genes would provide a better understanding of the still hypothetical Pneumocystislife cycle. Although difficult to achieve, stage purification seems a reasonable way forward in the absence of efficient culture systems. This mini-review provides a comprehensive overview of the historical milestones leading to the current knowledge available on the Pneumocystis life cycle.

Molecular characterization of environmental Cryptococcus neoformans isolated in Vitoria, ES, Brazil / Caracterização molecular de cepas ambientais de Cryptococcus neoformans isoladas em Vitória, ES, Brasil

Cryptococcus neoformans is the major cause of fungal meningitis, a potentially lethal mycosis. Bird excreta can be considered a significant environmental reservoir of this species in urban areas, thirty-three samples of pigeon excreta were collected within the city of Vitoria, Brazil. Cryptococcus neoformans was isolated and identified using standard biochemical assays in ten samples. PCR amplification with primer M13 and orotidine monophosphate pyrophosphorylase (URA5) gene-restriction fragment length polymorphism (RFLP) analysis discerned serotypes and genotypes within this species. All isolates were serotype A (C. neoformans var. grubii) and genotype VNI. The two alternative alleles a and α at the mating type locus were determined by PCR amplification and mating assays performed on V8 medium. All isolates were MAT α mating type but only 50 percent were able to mate in vitro with the opposite mating type MAT a tester strains (JEC20, KN99a and Bt63). This study adds information on the ecology and molecular characterization of C. neoformans in the Southeast region of Brazil.

O "complexo Cryptococcus neoformans" é constituído por C. neoformans var. neoformans, C. neoformans var. grubii, e C. gattii. Trinta por cento de amostras de excrementos de pombos coletados dentro da cidade de Vitória, Brasil, foram positivas para Cryptococcus neoformans, espécie identificada por testes bioquímicos convencionais. Amplificação por PCR com primer M13 e análise por orotidine monophosphate pyrophosphorylase (URA5) gene-"restriction fragment length polymorphism" (RFLP) distinguiram sorotipos e genotipos dentro desta espécie. Todos os isolados ambientais foram sorotipo A (C. neoformans var. grubii) e genotipo VNI. Os dois alelos alternativos a e α do locus "mating type" foram determinados por PCR e por testes de "mating" em meio V8. Todos os isolados foram "mating type" tipo MAT α mas somente 50 por cento foram capazes de conjugar in vitro com cepas MAT a, de "mating type" oposto (JEC20, KN99a e Bt63). Este estudo adiciona informações sobre a ecologia e caracterização molecular de cepas ambientais de C. neoformans, isoladas na região sudeste do Brasil.

Regional pattern of the molecular types of Cryptococcus neoformans and Cryptococcus gattii in Brazil

The molecular types of 443 Brazilian isolates of Cryptococcus neoformans and Cryptococcus gattii were analyzed to determine their geographic distribution within Brazil and their underlying host conditions. The following data, imported from previous epidemiological studies as well as two culture collections, were analyzed for: place of isolation, source (clinical or environmental), host risk factors, species, serotype, mating type, and molecular type. Molecular typing by PCR-fingerprinting using primers for the minisatellite-specific core sequence of the wild-type phage M13 or microsatellites [(GACA)4, (GTG)5], restriction fragment length polymorphism of URA5 gene analysis, and/or amplified fragment length polymorphism (AFLP) identified eight major genotypes: VNI/AFLP1, VNII/AFLP1A, VNIII/AFLP2, and VNIV/AFLP3 for C. neoformans, and VGI/AFLP4, VGII/AFLP6, VGIII/AFLP5, and VGIV/AFLP7 for C. gattii. The most common molecular type found in Brazil was VNI (64 percent), followed by VGII (21 percent), VNII (5 percent), VGIII (4 percent), VGI and VNIV (3 percent each), and VNIII (< 1 percent). Primary cryptococcosis caused by the molecular type VGII (serotype B, MAT) prevails in immunocompetent hosts in the North and Northeast regions, disclosing an endemic regional pattern for this specific molecular type in the Northern Brazil.

Serotype and mating type characterization of Cryptococcus neoformans by Multiplex PCR

Cryptococcus neoformans is an encapsulated yeast, etiological agent of cryptococcosis. The species is commonly associated with pigeon droppings and plant materials. The aim of the present work was to verify the presence of the yeast in pigeon droppings, and to identify the isolates obtained in serotypes and mating types (MAT). Ten samples of pigeon droppings were collected in the rural area of the city of Alfenas, Brazil. Samples were inoculated in agar Niger medium for fungal isolation and 22 isolates with characteristics of C. neoformans were obtained. The serotypes and MAT were determined by multiplex PCR using specific primers. Serotypes were also determined by using the Kit Crypto Check. Among the 22 samples evaluated, eight were identified as C. neoformans by classic identification tests. These samples were characterized as serotype A by the Kit Crypto check and as serotype A MAT alpha by the multiplex PCR. The present study reinforces the evidence that pigeon droppings are a reservoir for C. neoformans and confirms the prevalence of C. neoformans var. grubii (Aalpha) among environmental isolates. It also demonstrates that multiplex PCR is an acceptable alternative for serotype analysis because it reduces the costs for each reaction and analyses serotype and MAT simultaneously.

Cryptococcus neoformans é levedura encapsulada, agente etiológico da criptococose. As espécies são comumente associadas com fezes de pombos e material vegetal. O objetivo do presente trabalho foi verificar a presença de leveduras em fezes de pombos e identificar os isolados em relação aos sorotipos e "mating types". Dez amostras de fezes de pombos foram coletadas na zona rural da cidade de Alfenas, Brasil. As amostras foram inoculadas em agar Niger e 22 isolados com características de C. neoformans foram obtidos. Os sorotipos e "mating types" foram determinados pela PCR multiplex e os sorotipos foram identificados também pelo Kit Crypto Check. Dentre as 22 amostras avaliadas, oito foram identificadas como C. neoformans através dos testes clássicos. Estas amostras foram caracterizadas como sorotipo A pelo Kit Crypto check e como sorotipo A MATalfa pela PCR multiplex. O presente estudo reforça a evidência de que as fezes de pombos constituem reservatório para C. neoformans e confirma a prevalência de C. neoformans var. grubii (Aalfa) nos isolados ambientais. PCR multiplex é uma alternativa aceitável para análise do sorotipo porque reduz os custos de cada reação e analisa simultaneamente os sorotipos e "mating type".

Genotyping, serotyping and determination of mating-type of Cryptococcus neoformans clinical isolates from São Paulo State, Brazil

The basidiomycetous yeast Cryptococcus neoformans is an important fungal pathogen mainly in immunocompromised patients. In this study, 47 clinical isolates of C. neoformans from regions of São Paulo State were studied serologically by using the Crypto Check Iatron RM 304-K kit, their genetic diversity was estimated by PCR-fingerprinting with a microsatellite-specific sequence (GACA)4, RAPD with primer 6 (Amersham Pharmacia Biotech), PCR-restriction fragment length polymorphism (RFLP) analysis of the phospholipase B gene (PLB1) digested with AvaI and mating type analysis by PCR. All 47 strains isolated from HIV positive patients included in this study were serotype A and MATalpha. The majority of the isolates (45/47) were VNI and only two were VNII by PCR-fingerprinting and PCR-RFLP analysis. High degree of homogeneity was observed when (GACA)4 was used, being highly correlated (> 0.9). In contrast, the RAPD analysis was more heterogeneous with higher number of molecular profiles. By PCR-RFLP, no new molecular type was found, enhancing the suggestion that the differences based on conserved gene as PLB1, can be resultant of ongoing divergent evolution within the C. neoformans complex, into the current eight subtypes. Our results furnish new information on the molecular epidemiology of C. neoformans in the southeast region of Brazil.

Cryptococcus neoformans, pertencente à classe dos basidiomicetos, é um importante patógeno, principalmente em pacientes imunocomprometidos. Neste estudo, 47 isolados clínicos de C. neoformans de várias regiões do Estado de São Paulo foram avaliados quanto aos sorotipos e ao mating-type por PCR. A diversidade genética foi analisada por PCR-fingerprinting com a seqüência iniciadora específica para regiões microssatélite (GACA)4, RAPD com o iniciador 6 (Amersham Pharmacia Biotech) e por RFLP do gene PLB1 digerido com AvaI. Todos os isolados foram obtidos de pacientes HIV positivos e identificados como sorotipo A e MATalfa. A maioria dos isolados pertencia ao tipo molecular VNI (45/47) e apenas dois foram VNII quando analisados por PCR-fingerprinting e PCR-RFLP. Homogeneidade alta foi obtida com o iniciador (GACA)4, com a maioria dos isolados apresentando correlação alta (> 0.9). Os resultados do RAPD, por sua vez, revelaram maior heterogeneidade com número maior de perfis moleculares. Por PCR-RFLP, nenhum tipo molecular novo foi encontrado, realçando a idéia de que em genes conservados como PLB1, as diferenças podem ser resultantes de divergências evolutivas dentro do complexo C. neoformans, separando os isolados nos oito subtipos moleculares já estabelecidos. Nossos resultados fornecem novas informações sobre a epidemiologia molecular de C. neoformans na região sudeste do Brasil.