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1.
PLoS Genet ; 18(1): e1010001, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35007279

RESUMO

Invasive Pulmonary Aspergillosis, which is caused by the filamentous fungus Aspergillus fumigatus, is a life-threatening infection for immunosuppressed patients. Chromatin structure regulation is important for genome stability maintenance and has the potential to drive genome rearrangements and affect virulence and pathogenesis of pathogens. Here, we performed the first A. fumigatus global chromatin profiling of two histone modifications, H3K4me3 and H3K9me3, focusing on the two most investigated A. fumigatus clinical isolates, Af293 and CEA17. In eukaryotes, H3K4me3 is associated with active transcription, while H3K9me3 often marks silent genes, DNA repeats, and transposons. We found that H3K4me3 deposition is similar between the two isolates, while H3K9me3 is more variable and does not always represent transcriptional silencing. Our work uncovered striking differences in the number, locations, and expression of transposable elements between Af293 and CEA17, and the differences are correlated with H3K9me3 modifications and higher genomic variations among strains of Af293 background. Moreover, we further showed that the Af293 strains from different laboratories actually differ in their genome contents and found a frequently lost region in chromosome VIII. For one such Af293 variant, we identified the chromosomal changes and demonstrated their impacts on its secondary metabolites production, growth and virulence. Overall, our findings not only emphasize the influence of genome heterogeneity on A. fumigatus fitness, but also caution about unnoticed chromosomal variations among common laboratory strains.


Assuntos
Aspergillus fumigatus/classificação , Cromossomos Fúngicos/genética , Heterogeneidade Genética , Histonas/metabolismo , Aspergilose Pulmonar/microbiologia , Aspergillus fumigatus/genética , Aspergillus fumigatus/isolamento & purificação , Cromatina , Elementos de DNA Transponíveis , Proteínas Fúngicas/metabolismo , Regulação da Expressão Gênica de Plantas , Aptidão Genética , Código das Histonas , Humanos , Regiões Promotoras Genéticas , Metabolismo Secundário , Virulência
2.
Genes (Basel) ; 11(5)2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32397111

RESUMO

Single-celled eukaryote genomes predominantly replicate through multiple origins. Although origin usage during the S-phase has been elucidated in some of these organisms, few studies have comparatively approached this dynamic. Here, we developed a user-friendly website able to calculate the length of the cell cycle phases for any organism. Next, using a formula developed by our group, we showed a comparative analysis among the minimum number of replication origins (MO) required to duplicate an entire chromosome within the S-phase duration in trypanosomatids (Trypanosoma cruzi, Leishmania major, and Trypanosoma brucei) and yeasts (Saccharomyces cerevisiae and Schizosaccharomyces pombe). Using the data obtained by our analysis, it was possible to predict the MO required in a situation of replication stress. Also, our findings allow establishing a threshold for the number of origins, which serves as a parameter for genome approaches that map origins. Moreover, our data suggest that when compared to yeasts, trypanosomatids use much more origins than the minimum needed. This is the first time a comparative analysis of the minimum number of origins has been successfully applied. These data may provide new insight into the understanding of the replication mechanism and a new methodological framework for studying single-celled eukaryote genomes.


Assuntos
Cromossomos/genética , Leishmania major/genética , Origem de Replicação , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética , Trypanosoma brucei brucei/genética , Trypanosoma cruzi/genética , Ciclo Celular , Cromossomos/ultraestrutura , Cromossomos Fúngicos/genética , Cromossomos Fúngicos/ultraestrutura , Replicação do DNA , DNA Fúngico/genética , DNA de Protozoário/genética , Internet , Leishmania major/crescimento & desenvolvimento , Especificidade da Espécie , Trypanosoma cruzi/crescimento & desenvolvimento
3.
Fungal Biol ; 123(9): 687-697, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31416588

RESUMO

Kluyveromyces marxianus CCT 7735 has been used to produce ethanol, aromatic compounds, enzymes and heterologous proteins besides assimilates lactose as carbon source. Its genome has 10.7 Mb and encodes 4787 genes distributed in 8 nuclear chromosomes and one mitochondrial. Contrary to Kluyveromyces lactis, which has a unique LAC12 gene (encodes lactose permease), K. marxianus possesses four. The presence of degenerated copies and Solo-LTRs related to retrotransposon TKM close to the LAC12 genes in K. marxianus indicates ectopic recombinations. The Lac12 permeases of K. marxianus and K. lactis are conserved, however the conservation is higher between the copy of the left side of the chromosome three and the unique copy of K. lactis, indicating that this copy is the ancestor. The expression of the four LAC12 genes occurred in aerobiosis and hypoxia. Notably, the high lactose consumption in hypoxia seems to be related to the high expression of the LAC12 genes.


Assuntos
Proteínas Fúngicas/genética , Kluyveromyces/genética , Lactose/metabolismo , Proteínas de Membrana Transportadoras/genética , Aerobiose , Sequência de Aminoácidos , Transporte Biológico , Cromossomos Fúngicos/genética , Evolução Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Genômica , Kluyveromyces/química , Kluyveromyces/metabolismo , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Oxigênio/metabolismo , Filogenia , Recombinação Genética
4.
PLoS Genet ; 12(8): e1005876, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27512984

RESUMO

Black Sigatoka or black leaf streak disease, caused by the Dothideomycete fungus Pseudocercospora fijiensis (previously: Mycosphaerella fijiensis), is the most significant foliar disease of banana worldwide. Due to the lack of effective host resistance, management of this disease requires frequent fungicide applications, which greatly increase the economic and environmental costs to produce banana. Weekly applications in most banana plantations lead to rapid evolution of fungicide-resistant strains within populations causing disease-control failures throughout the world. Given its extremely high economic importance, two strains of P. fijiensis were sequenced and assembled with the aid of a new genetic linkage map. The 74-Mb genome of P. fijiensis is massively expanded by LTR retrotransposons, making it the largest genome within the Dothideomycetes. Melting-curve assays suggest that the genomes of two closely related members of the Sigatoka disease complex, P. eumusae and P. musae, also are expanded. Electrophoretic karyotyping and analyses of molecular markers in P. fijiensis field populations showed chromosome-length polymorphisms and high genetic diversity. Genetic differentiation was also detected using neutral markers, suggesting strong selection with limited gene flow at the studied geographic scale. Frequencies of fungicide resistance in fungicide-treated plantations were much higher than those in untreated wild-type P. fijiensis populations. A homologue of the Cladosporium fulvum Avr4 effector, PfAvr4, was identified in the P. fijiensis genome. Infiltration of the purified PfAVR4 protein into leaves of the resistant banana variety Calcutta 4 resulted in a hypersensitive-like response. This result suggests that Calcutta 4 could carry an unknown resistance gene recognizing PfAVR4. Besides adding to our understanding of the overall Dothideomycete genome structures, the P. fijiensis genome will aid in developing fungicide treatment schedules to combat this pathogen and in improving the efficiency of banana breeding programs.


Assuntos
Ascomicetos/genética , Resistência à Doença/genética , Musa/genética , Doenças das Plantas/genética , Folhas de Planta/genética , Ascomicetos/patogenicidade , Cruzamento , Cromossomos Fúngicos/genética , Variação Genética , Genoma Fúngico , Genótipo , Musa/crescimento & desenvolvimento , Musa/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Retroelementos/genética
5.
mBio ; 6(6): e01761-15, 2015 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-26578680

RESUMO

Cryptococcus gattii, the sister species of Cryptococcus neoformans, is an emerging pathogen which gained importance in connection with the ongoing cryptococcosis outbreak on Vancouver Island. Many molecular studies have divided this species into for major lineages: VGI, VGII, VGIII, and VGIV. This commentary summarizes the whole-genome sequencing (WGS) studies that have been carried out with this species, re-emphasizing the phylogenetic relationships, showing chromosomal rearrangements between those four groups, and identifying VGII as ancestral population within C. gattii. In addition, WGS specific to VGII, containing the Vancouver Island outbreak genotypes and those from the Pacific Northwest region of the United States, has placed the origin of this lineage within South America and identified specific genes responsible for either brain or lung infection. It also showed, that many genotypes are spread across a number of different continents, as has been previously shown by multilocus sequence typing (MLST). In addition, it showed that recombination occurs more frequently between mitochondrial than nuclear genomes.


Assuntos
Cryptococcus gattii/classificação , Cryptococcus gattii/genética , Variação Genética , Genoma Fúngico , América/epidemiologia , Cromossomos Fúngicos , Criptococose/epidemiologia , Criptococose/microbiologia , Cryptococcus gattii/isolamento & purificação , Rearranjo Gênico , Genótipo , Tipagem de Sequências Multilocus , Pandemias , Filogenia , Análise de Sequência de DNA
6.
PLoS One ; 9(1): e86819, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24466257

RESUMO

Sporotrichosis is a polymorphic disease caused by a complex of thermodimorphic fungi including S. brasiliensis, S. schenckii sensu stricto (s. str.), S. globosa and S. luriei. Humans and animals can acquire the disease through traumatic inoculation of propagules into the subcutaneous tissue. Despite the importance of sporotrichosis as a disease that can take epidemic proportions there are just a few studies dealing with genetic polymorphisms and genomic architecture of these pathogens. The main objective of this study was to investigate chromosomal polymorphisms and genomic organization among different isolates in the S. schenckii complex. We used pulsed field gel electrophoresis (PFGE) to separate chromosomal fragments of isolated DNA, followed by probe hybridization. Nine loci (ß-tubulin, calmodulin, catalase, chitin synthase 1, Internal Transcribed Spacer, Pho85 cyclin-dependent kinase, protein kinase C Ss-2, G protein α subunit and topoisomerase II) were mapped onto chromosomal bands of Brazilian isolates of S. schenckii s. str. and S. brasiliensis. Our results revealed the presence of intra and interspecies polymorphisms in chromosome number and size. The gene hybridization analysis showed that closely related species in phylogenetic analysis had similar genetic organizations, mostly due to identification of synteny groups in chromosomal bands of similar sizes. Our results bring new insights into the genetic diversity and genome organization among pathogenic species in the Sporothrix schenckii complex.


Assuntos
Cromossomos Fúngicos/genética , DNA Fúngico/genética , Polimorfismo Genético/genética , Sporothrix/genética , Sporothrix/patogenicidade , Esporotricose/microbiologia , Virulência/genética , Southern Blotting , Eletroforese em Gel de Campo Pulsado , Marcadores Genéticos , Variação Genética , Cariotipagem , Filogenia , Reação em Cadeia da Polimerase , Sporothrix/classificação , Esporotricose/genética
7.
Rev Iberoam Micol ; 31(1): 30-4, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24252826

RESUMO

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


Assuntos
Candida glabrata/genética , Proteínas Fúngicas/genética , Genes Fúngicos Tipo Acasalamento , Candida glabrata/fisiologia , Cromossomos Fúngicos , Proteínas Fúngicas/fisiologia , Regulação Fúngica da Expressão Gênica , Inativação Gênica , Reprodução , Telômero , Transcrição Gênica
8.
Med Mycol ; 51(2): 208-13, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22852750

RESUMO

The karyotype of Microsporum canis was analyzed by contoured-clamped homogeneous electric field (CHEF) gel electrophoresis. Four chromosomal bands that correspond to five chromosomes ranging from 3.0-6.2 Mb were identified, adding the total genome size to approximately 24.9 Mb. To confirm the number of chromosomes in M. canis, the number of telomeres was assessed by using a telomeric probe (TTAGGG)(4) in Southern blot analyses of digested genomic DNA. Treatment of M. canis DNA with Bal31 exonuclease revealed progressive shortening of the DNA fragments positive for the (TTAGGG)(4) sequence, supporting location of repeats at the chromosome ends. These results can aid in improving the understanding of the genetic characterization of M. canis and the molecular epidemiology of dermatophytoses caused by this fungus.


Assuntos
Cromossomos Fúngicos/genética , Tamanho do Genoma , Genoma Fúngico/genética , Microsporum/genética , Southern Blotting , Mapeamento Cromossômico , Impressões Digitais de DNA , DNA Fúngico/genética , Eletroforese em Gel de Campo Pulsado , Endodesoxirribonucleases , Cariotipagem , Telômero
9.
Genet Mol Res ; 11(3): 1810-8, 2012 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-22869537

RESUMO

Imidocarb dipropionate (IMD) is a chemotherapeutic agent prescribed for the treatment and control of babesiosis; it is known to be a nucleic acid synthesis inhibitor. Although it is an effective babesicide, there are reports of persistent IMD residues retained at high levels in edible tissues of cattle, swine and sheep, raising concerns about potential effects on humans. Since the carcinogenic potential of a chemical compound can be assessed through its effect on the homologous recombination, we investigated whether IMD is recombinogenic in Aspergillus nidulans diploid cells and whether it is capable of inducing homozygosis in genes that were previously heterozygous. This analysis was done with a homozygotization assay applied to a heterozygous diploid strain of A. nidulans. IMD used at non-toxic concentrations (2.5 to 10.0 µM) was recombinogenic, demonstrated by homozygotization indices higher than 2.0 for diploid markers. A diploid homozygous for genetic markers from chromosomes I and II was also produced. Since DNA replication blockers that induce DNA strand breaks have been classified as potent inducers of homologous recombination, the recombinogenic potential of IMD may be due to induction of recombinational repair.


Assuntos
Antiprotozoários/farmacologia , Aspergillus nidulans/citologia , Aspergillus nidulans/genética , Diploide , Imidocarbo/análogos & derivados , Mitose/efeitos dos fármacos , Recombinação Genética/efeitos dos fármacos , Animais , Aspergillus nidulans/efeitos dos fármacos , Babesia/efeitos dos fármacos , Bovinos , Cromossomos Fúngicos/genética , Troca Genética/efeitos dos fármacos , Genótipo , Imidocarbo/farmacologia
10.
Methods Mol Biol ; 898: 195-205, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22711127

RESUMO

Double-stranded RNA (dsRNA) molecules are widely found in yeasts and filamentous fungi. It has been suggested that may play important roles in the evolution of eukaryote genomes and may be a valuable tool in yeast typing. The characterization of these extrachromosomal genetic elements is usually a laborious process, especially when trying to analyze a large number of samples. In this chapter, we describe a simple method to isolate dsRNA elements from yeasts using low amounts of starting material, and their application to different Xanthophyllomyces dendrorhous strains. Furthermore, the methodologies for enzymatic and hybridization characterizations, and quantification of relative dsRNA abundance are detailed.


Assuntos
Basidiomycota/citologia , Fracionamento Químico/métodos , Cromossomos Fúngicos/química , RNA de Cadeia Dupla/química , RNA de Cadeia Dupla/isolamento & purificação , RNA Fúngico/química , RNA Fúngico/isolamento & purificação , Basidiomycota/genética , DNA Complementar/biossíntese , Membranas Artificiais , Hibridização de Ácido Nucleico
11.
J Ind Microbiol Biotechnol ; 37(10): 1071-9, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20532588

RESUMO

The stress sensitivity of different wild-type strains was evaluated, as well as the response of cells arrested at different cell cycle positions to high hydrostatic pressure (HPP). HHP was chosen both for its importance in food decontamination and assessment of its suitability as a model for stress in general and understanding the yeast stress response. Studies were conducted with four industrial strains and four laboratory wild-type yeast strains (two haploid and two diploid) that differed in their backgrounds. Fundamental differences were found between the laboratory and industrial populations. Industrial strains were clearly more sensitive to hydrostatic pressure and ethanol stresses than the laboratory strains. However, ethanol production was higher in industrial strains than laboratory strains. Furthermore, no correlation was observed between ploidy and stress resistance. Yeast cells arrested in the G1 phase led to an enhancement in pressure tolerance compared to unarrested, G2 arrested, and S arrested cells. Moreover, cells arrested in the S phase were more sensitive to hydrostatic pressure than cells arrested in the G2 phase. Again, industrial strains were more sensitive than laboratory strains. HHP responses of industrial yeasts correlated well with both ethanol concentration and temperature stress, which suggests that it would be a useful model stress.


Assuntos
Indústria Alimentícia , Microbiologia Industrial , Estresse Fisiológico , Leveduras/fisiologia , Antifúngicos/toxicidade , Ciclo Celular , Cromossomos Fúngicos , Etanol/toxicidade , Pressão Hidrostática , Ploidias , Leveduras/citologia , Leveduras/efeitos dos fármacos , Leveduras/genética
12.
Braz. j. microbiol ; Braz. j. microbiol;41(1): 264-269, Jan.-Mar. 2010. ilus
Artigo em Inglês | LILACS | ID: lil-531760

RESUMO

A development mutant, named V103, was obtained spontaneously from the A strain of A. nidulans. The A strain contains a duplicated segment of chromosome I that has undergone translocation to chromosome II (I ¨ II). It is mitotically unstable and generates phenotypically deteriorated types, some with enhanced stability. The deteriorated variants of A. nidulans show abnormal development, exhibiting slower colony growth, variations in colony pigmentation and changes in conidiophore structure. The alterations observed in the conidiophore include fewer metulae and phialides, further elongation and ramification of these structures, delayed nuclear migration and the presence of secondary conidiophores.


Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/isolamento & purificação , Movimento Celular , Cromossomos Fúngicos , Esporos Fúngicos/genética , Fenótipo , Supressão Genética , Métodos , Microscopia Eletrônica , Métodos , Virulência
13.
Genome Res ; 19(12): 2258-70, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19812109

RESUMO

Bioethanol is a biofuel produced mainly from the fermentation of carbohydrates derived from agricultural feedstocks by the yeast Saccharomyces cerevisiae. One of the most widely adopted strains is PE-2, a heterothallic diploid naturally adapted to the sugar cane fermentation process used in Brazil. Here we report the molecular genetic analysis of a PE-2 derived diploid (JAY270), and the complete genome sequence of a haploid derivative (JAY291). The JAY270 genome is highly heterozygous (approximately 2 SNPs/kb) and has several structural polymorphisms between homologous chromosomes. These chromosomal rearrangements are confined to the peripheral regions of the chromosomes, with breakpoints within repetitive DNA sequences. Despite its complex karyotype, this diploid, when sporulated, had a high frequency of viable spores. Hybrid diploids formed by outcrossing with the laboratory strain S288c also displayed good spore viability. Thus, the rearrangements that exist near the ends of chromosomes do not impair meiosis, as they do not span regions that contain essential genes. This observation is consistent with a model in which the peripheral regions of chromosomes represent plastic domains of the genome that are free to recombine ectopically and experiment with alternative structures. We also explored features of the JAY270 and JAY291 genomes that help explain their high adaptation to industrial environments, exhibiting desirable phenotypes such as high ethanol and cell mass production and high temperature and oxidative stress tolerance. The genomic manipulation of such strains could enable the creation of a new generation of industrial organisms, ideally suited for use as delivery vehicles for future bioenergy technologies.


Assuntos
Biocombustíveis , Etanol/metabolismo , Genoma Fúngico/genética , Microbiologia Industrial , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/genética , Brasil , Cromossomos Fúngicos , DNA Fúngico/análise , Diploide , Fermentação , Haploidia , Dados de Sequência Molecular , Fenótipo , Polimorfismo Genético , Proteínas de Saccharomyces cerevisiae , Análise de Sequência de DNA , Esporos Fúngicos/genética , Esporos Fúngicos/fisiologia
14.
Genet Mol Res ; 8(2): 404-13, 2009 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-19440976

RESUMO

Mercury (Hg) pollution is one of the most serious environmental problems. Due to public concern prompted by the symptoms displayed by people who consumed contaminated fish in Minamata, Japan in 1956, Hg pollution has since been kept under constant surveillance. However, despite considerable accumulation of knowledge on the noxious effects of ingested or inhaled Hg, especially for humans, there is virtually nothing known about the genotoxic effects of Hg. Because increased mitotic crossing over is assumed to be the first step leading to carcinogenesis, we used a sensitive short-term test (homozygotization index) to look for DNA alterations induced by Hg fumes. In one Aspergillus nidulans diploid strain (UT448//UT184), the effects of the Hg fumes appeared scattered all over the DNA, causing 3.05 times more recombination frequencies than the mean for other strains. Another diploid (Dp II-I//UT184) was little affected by Hg. This led us to hypothesize that a genetic factor present in the UT184 master strain genome, close to the nicB8 genetic marker, is responsible for this behavior. These findings corroborate our previous findings that the homozygotization index can be used as a bioassay for rapid and efficient assessment of ecotoxicological hazards.


Assuntos
Poluentes Atmosféricos/toxicidade , Aspergillus nidulans/efeitos dos fármacos , Aspergillus nidulans/genética , Células Eucarióticas/efeitos dos fármacos , Células Eucarióticas/metabolismo , Mercúrio/toxicidade , Testes de Mutagenicidade/métodos , Cromossomos Fúngicos/genética , Troca Genética/efeitos dos fármacos , DNA Fúngico/genética , Diploide , Monitoramento Ambiental
15.
Biol Res ; 41(2): 173-82, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18949135

RESUMO

The secretion of proteinaceous toxins is a widespread characteristic in environmental and laboratory yeast isolates, a phenomenon called "killer system". The killer phenotype (K+) can be encoded by extrachromosomal genetic elements (EGEs) as double stranded DNA or RNA molecules (dsDNA, dsRNA) or in nuclear genes. The spectrum of action and the activity of killer toxins are influenced by temperature, salinity and pH of media. In the present work we determined the existence of K+ in a collection of S. cerevisiae and P. anomala yeasts isolated from environmental, industrial and clinical sources. The assays were performed in strains belonging to three yeast genera used as sensitive cells and under a wide range of pH and temperatures. Approximately 51 % of isolates tested showed toxicity against at least one sensitive yeast strain under the conditions tested. The K+ P. anomala isolates showed a wide spectrum of action and two of them had toxic activity against strains of the three yeast genera assayed, including C. albicans strains. In all S. cerevisiae K+ isolates an extrachromosomal dsRNA molecule (4.2 Kb) was observed, contrary to P. anomala K+ isolates, which do not possess any EGEs. The K+ phenotype is produced by an exported protein factor and the kinetics of killer activity production was similar in all isolates with high activity in the log phase of growth, decaying in the stationary phase.


Assuntos
Fatores Matadores de Levedura/biossíntese , Pichia/metabolismo , Saccharomyces cerevisiae/metabolismo , Cromossomos Fúngicos/genética , DNA Fúngico/genética , DNA Mitocondrial/genética , Eletroforese em Gel de Ágar , Meio Ambiente , Humanos , Concentração de Íons de Hidrogênio , Fenótipo , Pichia/genética , Reação em Cadeia da Polimerase , Saccharomyces cerevisiae/genética , Temperatura
16.
Fungal Genet Biol ; 45 Suppl 1: S54-62, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18514000

RESUMO

Telomeres are specialized caps of nucleoprotein complexes located at the chromosome termini. They consist of short DNA repeats and of an assortment of associated proteins whose function is currently under intense investigation in model systems. These specialized structures protect the linear ends of eukaryotic chromosomes against DNA repair and degradation activities, and serve as the substrate for telomerase, the ribonucleoprotein complex that synthesises the telomere repeats. The pivotal role of the telomeres in the maintenance of cell viability in several model eukaryotes, including humans, greatly promoted research in telomere biology. Studies on telomere structure and function in fungi other than model systems are limited to providing information on the telomeric repeat sequences. Here, we have summarized the current knowledge on the organization of chromosome ends and on the proteins participating in telomere function in model systems including recent information obtained for filamentous fungi. We also describe Ustilago maydis genes that are potential homologs of proteins known from other systems to participate in telomere biology.


Assuntos
Cromossomos Fúngicos/genética , Telômero/genética , Ustilago/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Telomerase/genética , Telomerase/metabolismo , Telômero/metabolismo , Ustilago/metabolismo
17.
Biol. Res ; 41(2): 173-182, 2008. ilus, tab, graf
Artigo em Inglês | LILACS | ID: lil-495752

RESUMO

The secretion of proteinaceous toxins is a widespread characteristic in environmental and laboratory yeast isolates, a phenomenon called "killer system". The killer phenotype (K+) can be encoded by extrachromosomal genetic elements (EGEs) as double stranded DNA or RNA molecules (dsDNA, dsRNA) or in nuclear genes. The spectrum of action and the activity of killer toxins are influenced by temperature, salinity and pH of media. In the present work we determined the existence of K+ in a collection of S. cerevisiae and P. anómala yeasts isolated from environmental, industrial and clinical sources. The assays were performed in strains belonging to three yeast genera used as sensitive cells and under a wide range of pH and temperatures. Approximately 51 percent of isolates tested showed toxicity against at least one sensitive yeast strain under the conditions tested. The K+ P. anómala isolates showed a wide spectrum of action and two of them had toxic activity against strains of the three yeast genera assayed, including C. albicans strains. In all S. cerevisiae K+ isolates an extrachromosomal dsRNA molecule (4.2 Kb) was observed, contrary to P. anómala K+ isolates, which do not possess any EGEs. The K+ phenotype is produced by an exported protein factor and the kinetics of killer activity production was similar in all isolates with high activity in the log phase of growth, decaying in the stationary phase.


Assuntos
Humanos , Fatores Matadores de Levedura/biossíntese , Pichia/metabolismo , Saccharomyces cerevisiae/metabolismo , Cromossomos Fúngicos/genética , DNA Fúngico/genética , DNA Mitocondrial/genética , Eletroforese em Gel de Ágar , Meio Ambiente , Concentração de Íons de Hidrogênio , Fenótipo , Reação em Cadeia da Polimerase , Pichia/genética , Saccharomyces cerevisiae/genética , Temperatura
18.
Genet Mol Res ; 6(4): 1072-84, 2007 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-18273800

RESUMO

Industrial ethanol fermentation is a complex microbiological process to which yeast cells must adapt for survival. One of the mechanisms for adaptation is thought to involve chromosome rearrangements. We found that changes in chromosome banding patterns measured by pulsed-field gel electrophoresis can also be produced in laboratory media under simulated industrial conditions. Based on analysis of their generational variation, we found that these chromosome changes were specific to the genetic backgrounds of the initial strains. We conclude that chromosome rearrangements could be one of the factors involved in yeast cell adaptation to the industrial environment.


Assuntos
Cromossomos Fúngicos/genética , Saccharomyces cerevisiae/genética , Adaptação Fisiológica , Reatores Biológicos/microbiologia , Biotecnologia , Instabilidade Cromossômica , Impressões Digitais de DNA , DNA Fúngico/genética , DNA Fúngico/isolamento & purificação , Etanol/metabolismo , Fermentação , Cariotipagem , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/fisiologia
19.
Fungal Genet Biol ; 44(1): 25-31, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16879998

RESUMO

The aim of this study was to evaluate genome size and ploidy of the dimorphic pathogenic fungus Paracoccidioides brasiliensis. The cell cycle analysis of 10 P. brasiliensis isolates by flow cytometry (FCM) revealed a genome size ranging from 26.3+/-0.1Mb (26.9+/-0.1fg) to 35.5+/-0.2Mb (36.3+/-0.2fg) per uninucleated yeast cell. The DNA content of conidia from P. brasiliensis ATCC 60855-30.2+/-0.8Mb (30.9+/-0.8fg) -showed no significant differences with the yeast form, possibly excluding the occurrence of ploidy shift during morphogenesis. The ploidy of several P. brasiliensis isolates was assessed by comparing genome sizing by FCM with the previously described average haploid size obtained from electrophoretic karyotyping. The analysis of intra-individual variability of a highly polymorphic P. brasiliensis gene, GP43, indicated that only one allele seems to be present. Overall, the results showed that all analysed isolates presented a haploid, or at least aneuploid, DNA content and no association was detected between genome size/ploidy and the clinical-epidemiological features of the studied isolates. This work provides new knowledge on P. brasiliensis genetics/genomics, important for future research in basic cellular/molecular mechanisms and for the development/design of molecular techniques in this fungus.


Assuntos
Antígenos de Fungos/genética , DNA Fúngico/análise , Proteínas Fúngicas/genética , Genoma Fúngico , Glicoproteínas/genética , Haploidia , Paracoccidioides/genética , Cromossomos Fúngicos , DNA Fúngico/química , Citometria de Fluxo , Cariotipagem , Paracoccidioides/classificação , Paracoccidioides/crescimento & desenvolvimento , Ploidias , Análise de Sequência de DNA
20.
Genet. mol. res. (Online) ; Genet. mol. res. (Online);6(4): 1072-1084, 2007. ilus
Artigo em Inglês | LILACS | ID: lil-520042

RESUMO

Industrial ethanol fermentation is a complex microbiological process to which yeast cells must adapt for survival. One of the mechanisms for adaptation is thought to involve chromosome rearrangements. We found that changes in chromosome banding patterns measured by pulsed-field gel electrophoresis can also be produced in laboratory media under simulated industrial conditions. Based on analysis of their generational variation, we found that these chromosome changes were specific to the genetic backgrounds of the initial strains. We conclude that chromosome rearrangements could be one of the factors involved in yeast cell adaptation to the industrial environment.


Assuntos
Instabilidade Cromossômica , Cromossomos Fúngicos/genética , DNA Fúngico/genética , Etanol/metabolismo , Saccharomyces cerevisiae/genética , Adaptação Fisiológica , Biotecnologia , Impressões Digitais de DNA , DNA Fúngico/isolamento & purificação , Fermentação , Cariotipagem , Reatores Biológicos/microbiologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/fisiologia
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