Navegando por Autor "Bazzolli, Denise Mara Soares"
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Item Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus(PLoS One, 2014-11-24) Luz, José Maria Rodrigues da; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina MegumiIn this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxobiodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo- biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO 2 ) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.Item Antimicrobial resistance, biofilm formation and virulence reveal Actinobacillus pleuropneumoniae strains' pathogenicity complexity(Research in Veterinary Science, 2018-06) Pereira, Monalessa Fábia; Rossi, Ciro César; Seide, Larissa Eler; Martins Filho, Sebastião; Dolinski, Cláudia de Melo; Bazzolli, Denise Mara SoaresPorcine pleuropneumonia is an important cause of lowered productivity and economic loss in the pig industry worldwide, associated primarily with Actinobacillus pleuropneumoniae infection. Its colonization and persistence within the upper respiratory tract of affected pigs depends upon interactions between a number of genetically controlled virulence factors, such as pore-forming repeats-in-toxin exoproteins, biofilm formation, and antimicrobial resistance. This study investigated correlations between biofilm-forming capacity, antimicrobial resistance, and virulence of A. pleuropneumoniae obtained from clinical outbreaks of disease, using a Galleria mellonella alternative infection model. Results suggest that virulence is diverse amongst the 21 strains of A. pleuropneumoniae examined and biofilm formation correlated with genetic control of antimicrobial resistance.Item Beginning to understand the role of sugar carriers in Colletotrichum lindemuthianum: the function of the gene mfs1(Journal of Microbiology, 2012-10-12) Pereira, Monalessa Fábia; Santos, Carolina Maria de Araújo dos; Araújo, Elza Fernandes de; Queiroz, Marisa Vieira de; Bazzolli, Denise Mara SoaresFungi of the Colletotrichum genus are among the most prominent phytopathogens that cause diseases with a considerable economic impact, such as anthracnose. The hemibiotrophic fungus Colletotrichum lindemuthianum (teleomorph Glomerella cingulata f. sp. phaseoli) is the causal agent of the anthracnose of the common bean; and similarly to other phytopathogens, it uses multiple strategies to gain access to different carbon sources from its host. In this study, we examine mfs1, a newly identified C. lindemuthianum hexose transporter. The mfs1 gene is expressed only during the necrotrophic phase of the fungus’ interaction within the plant and allows it to utilize the available sugars during this phase. The deletion of mfs1 gene resulted in differential growth of the fungus in a medium that contained glucose, mannose or fructose as the only carbon source. This study is the first to describe a hexose transporter in the hemibiotrophic pathogen C. lindemuthianum and to demonstrate the central role of this protein in capturing carbon sources during the necrotrophic development of the plant/pathogen interaction.Item Characterization of the omlA gene from different serotypes of Actinobacillus pleuropneumoniae: a new insight into an old approach(Genetics and Molecular Biology, 2013-01-29) Rossi, Ciro César; Araújo, Elza Fernandes de; Queiroz, Marisa Vieira de; Bazzolli, Denise Mara SoaresThe OmlA protein is a virulence factor of Actinobacillus pleuropneumoniae, an important pathogen in pigs. The polymorphisms present in the omlA gene sequence of 15 reference serotypes of A. pleuropneumoniae and non-serotypable isolates were assessed to determine the possible evolutionary relationship among them and to validate the importance of this gene as a molecular marker for the characterization of this bacterium. Divergence among the 15 serotypes of A. pleuropneumoniae probably resulted initially from two major evolutionary events that led to subsequent differentiation into nine groups. This differentiation makes it possible to characterize most of the serotypes by using bionformatics, thereby avoiding problems with immunological cross-reactivity. A conserved α-helix common to all the serotypes was most likely involved in connecting the protein to the outer membrane and acting as a signal peptide. A previously unknown gene duplication was also identified and could contribute to the genetic variability that makes it difficult to serotype some isolates. Our data support the importance of the omlA gene in the biology of A. pleuropneumoniae and provide a new area of research into the OmlA protein.Item Differential cellular immune response of Galleria mellonella to Actinobacillus pleuropneumoniae(Cell and Tissue Research, 2017-07-08) Blanco, Luis Andrés Arteaga; Crispim, Josicelli Souza; Fernandes, Kenner Morais; Oliveira, Leandro Licursi de; Pereira, Monalessa Fábia; Bazzolli, Denise Mara Soares; Martins, Gustavo FerreiraIn the present work, we have investigate the cellular immune response of Galleria mellonella larvae against three strains of the gram-negative bacterium Actinobacillus pleuropneumoniae: low-virulence (780), high-virulence (1022) and the serotype 8 reference strain (R8). Prohemocytes, plasmatocytes, granulocytes, oenocytoids and spherulocytes were distinguished according to their size and morphology, their molecular markers and dye-staining properties and their role in the immune response. Total hemocyte count, differential hemocyte count, lysosome activity, autophagic response, cell viability and caspase-3 activation were determined in circulating hemocytes of naive and infected larvae. The presence of the autophagosome protein LC3 A/B within the circulating hemocytes of G. mellonella was dependent on and related to the infecting A. pleuropneumoniae strain and duration of infection. Hemocytes treated with the high-virulence strain expressed higher levels of LC3 A/B, whereas treatment with the low-virulence strain induced lower expression levels of this protein in the cells. Moreover, our results showed that apoptosis in circulating hemocytes of G. mellonella larvae after exposure to virulent bacterial strains occurred simultaneously with excessive cell death response induced by stress and subsequent caspase-3 activation.Item Draft Genome Sequences of Six Actinobacillus pleuropneumoniae Serotype 8 Brazilian Clinical Isolates: Insight into New Applications(Genome Announcements, 2015-03-05) Pereira, Monalessa Fábia; Rossi, Ciro César; Carvalho, Fabíola Marques de; Almeida, Luiz Gonzaga Paula de; Souza, Rangel Celso; Vasconcelos, Ana Tereza Ribeiro de; Bazzolli, Denise Mara SoaresActinobacillus pleuropneumoniae is the causative agent of swine pleuropneumonia, a highly contagious disease associated with pigs of all ages that results in severe economic losses to the industry. Here, we report for the first time six genome sequences of A. pleuropneumoniae clinical isolates of serotype 8, found worldwide.Item Enrichment of mushrooms: an interesting strategy for the acquisition of lithium(PubMed, 2012-03-19) Assunção, Laélia Soares de; Luz, José Maria Rodrigues da; Silva, Marliane de Cássia Soares da; Vieira, Patrícia Aparecida Fontes; Bazzolli, Denise Mara Soares; Vanetti, Maria Cristina Dantas; Kasuya, Maria Catarina MegumiThe capability of Pleurotus ostreatus mushroom to accumulate lithium (Li) and the accessibility of this Li compared with lithium carbonate (Li2CO3), often used as psychiatric medicine, were investigated. Mushrooms were produced on a substrate-based on coffee husk, with different added concentrations of lithium chloride (LiCl). Biological efficiency (BE), the crude protein content, the concentration of Li and other elements present in mushrooms were determined. The sequential extraction and in vitro test were used to verify the accessibility and the degree of solubility of this element. Li concentration in mushrooms was directly influenced by increasing LiCl concentration in the substrate (P < 0.05). The BE was not affected by different concentrations of LiCl. Li present in enriched mushrooms showed greater accessibility than in Li2CO3. Therefore, P. ostreatus mushrooms, enriched with lithium can be an alternative source of Li, as well as being a food with high nutritional value.Item Ethanol stress responses of Kluyveromyces marxianus CCT 7735 revealed by proteomic and metabolomic analyses(Antonie van Leeuwenhoek, 2019) Alvim, Mariana Caroline Tocantins; Vital, Camilo Elber; Vieira, Nívea Moreira; Silveira, Fernando Augusto da; Balbino, Thércia Rocha; Diniz, Raphael Hermano Santos; Brito, Amanda Fernandes; Bazzolli, Denise Mara Soares; Silveira, Wendel Batista da; Barros, Edvaldo; Ramos, Humberto Josué de OliveiraKluyveromyces marxianus CCT 7735 offers advantages to ethanol production over Saccharomyces cerevisiae, including thermotolerance and the ability to convert lactose to ethanol. However, its growth is impaired at high ethanol concentrations. Herein we report on the protein and intracellular metabolite profiles of K. marxianus at 1 and 4 h under ethanol exposure. The concentration of some amino acids, trehalose and ergosterol were also measured. We observed that proteins and metabolites from carbon pathways and translation were less abundant, mainly at 4 h of ethanol stress. Nevertheless, the concentration of some amino acids and trehalose increased at 8 and 12 h under ethanol stress, indicating an adaptive response. Moreover, our results show that the abundance of proteins and metabolites related to the oxidative stresses responses increased. The results obtained in this study provide insights into understanding the physiological changes in K. marxianus under ethanol stress, indicating possible targets for ethanol tolerant strains construction.Item Evidence of illegitimate recombination between two pasteurellaceae plasmids resulting in a novel multi-resistance replicon, pM3362MDR, in Actinobacillus pleuropneumoniae(Frontiers in Microbiology, 2018-10) Silva, Giarlã Cunha da; Li, Yinghui; Li, Yanwen; Rossi, Ciro C.; Crespo, Roberto Fernandez; Williamson, Susanna M.; Langford, Paul R.; Bazzolli, Denise Mara Soares; Bossé, Janine T.Evidence of plasmids carrying the tetracycline resistance gene, tet(B), was found in the previously reported whole genome sequences of 14 United Kingdom, and 4 Brazilian, isolates of Actinobacillus pleuropneumoniae. Isolation and sequencing of selected plasmids, combined with comparative sequence analysis, indicated that the four Brazilian isolates all harbor plasmids that are nearly identical to pB1001, a plasmid previously found in Pasteurella multocida isolates from Spain. Of the United Kingdom isolates, 13/14 harbor plasmids that are (almost) identical to pTetHS016 from Haemophilus parasuis. The remaining United Kingdom isolate, MIDG3362, harbors a 12666 bp plasmid that shares extensive regions of similarity with pOV from P. multocida (which carries bla ROB−1 , sul2, and strAB genes), as well as with pTetHS016. The newly identified multi-resistance plasmid, pM3362MDR, appears to have arisen through illegitimate recombination of pTetHS016 into the stop codon of the truncated strB gene in a pOV-like plasmid. All of the tet(B)-carrying plasmids studied were capable of replicating in Escherichia coli, and predicted origins of replication were identified. A putative origin of transfer (oriT) sequence with similar secondary structure and a nic-site almost identical to that of RP4 was also identified in these plasmids, however, attempts to mobilize them from an RP4-encoding E. coli donor strain were not successful, indicating that specific conjugation machinery may be required.Item Expression of the nifH gene in diazotrophic bacteria in Eucalyptus urograndis plantations(Canadian Journal of Forest Research, 2016-02) Silva, Marliane de Cássia Soares da; Mendes, Igor Rodrigues; Paula, Thiago de Almeida; Dias, Roberto Sousa; Paula, Sérgio Oliveira de; Silva, Cynthia Canedo; Bazzolli, Denise Mara Soares; Kasuya, Maria Catarina MegumiA large proportion of eucalypt plantations in Brazil are located in areas with low soil fertility. The actions of microorganisms are of great importance for the cycling of nutrients, including nitrogen (N), that are essential for plant metabolism. Denaturing gradient gel electrophoresis (DGGE) was used to monitor and identify the total and active microorganisms involved in the N cycle in both the soil and root systems of a forest of Eucalyptus urograndis with sections that were fertilized with N or unfertilized. Quantitative real-time PCR was used to examine the expression of the nifH gene in N-fixing bacteria present in both the soil and root systems. According to the DGGE analysis, in the total and active populations of N-fixing bacteria, the presence and expression of the nifH gene were influenced by the winter and summer seasons and (or) N fertilization, respectively. DGGE band sequencing from total DNA samples showed that the most abundant group of diazotrophic bacteria belonged to Alphaproteobacteria in both the soil and root systems. Quantitative real-time PCR revealed that nifH expression was higher in the soil samples, especially in those that did not receive N fertilization. The differences in the composition of the total and active diazotrophic populations highlight the importance of evaluating the active populations, because they are effectively responsible for the biogeochemical transformation of N and also control its' availability to plants.Item Galleria mellonella is an effective model to study Actinobacillus pleuropneumoniae infection(Microbiology, 2014-11-14) Pereira, Monalessa Fábia; Rossi, Ciro César; Queiroz, Marisa Vieira de; Martins, Gustavo Ferreira; Isaac, Clement; Bossé, Janine T.; Li, Yanwen; Wren, Brendan W.; Terra, Vanessa Sofia; Cuccui, Jon; Langford, Paul R.; Bazzolli, Denise Mara SoaresActinobacillus pleuropneumoniae is responsible for swine pleuropneumonia, a respiratory disease that causes significant global economic loss. Its virulence depends on many factors, such as capsular polysaccharides, RTX toxins and iron-acquisition systems. Analysis of virulence may require easy-to-use models that approximate mammalian infection and avoid ethical issues. Here, we investigate the potential use of the wax moth Galleria mellonella as an informative model for A. pleuropneumoniae infection. Genotypically distinct A. pleuropneumoniae clinical isolates were able to kill larvae at 37 6C but had different LD 50 values, ranging from 10 4 to 10 7 c.f.u. per larva. The most virulent isolate (1022) was able to persist and replicate within the insect, while the least virulent (780) was rapidly cleared. We observed a decrease in haemocyte concentration, aggregation and DNA damage post-infection with isolate 1022. Melanization points around bacterial cells were observed in the fat body and pericardial tissues of infected G. mellonella, indicating vigorous cell and humoral immune responses close to the larval dorsal vessel. As found in pigs, an A. pleuropneumoniae hfq mutant was significantly attenuated for infection in the G. mellonella model. Additionally, the model could be used to assess the effectiveness of several antimicrobial agents against A. pleuropneumoniae in vivo. G. mellonella is a suitable inexpensive alternative infection model that can be used to study the virulence of A. pleuropneumoniae, as well as assess the effectiveness of antimicrobial agents against this pathogen.Item The histidine kinase slnCl1 of Colletotrichum lindemuthianum as a pathogenicity factor against Phaseolus vulgaris L(Microbiological Research, 2019-02) Nogueira, Guilherme Bicalho; Santos, Leandro Vieira dos; Queiroz, Casley Borges de; Corrêa, Thamy Lívia Ribeiro; Menicucci, Renato Pedrozo; Bazzolli, Denise Mara Soares; Araújo, Elza Fernandes de; Queiroz, Marisa Vieira deColletotrichum lindemuthianum, the causal agent of anthracnose, is responsible for significant damage in the common bean (Phaseolus vulgaris L.). Unraveling the genetic mechanisms involved in the plant/pathogen interaction is a powerful approach for devising efficient methods to control this disease. In the present study, we employed the Restriction Enzyme-Mediated Integration (REMI) methodology to identify the gene slnCl1, encoding a histidine kinase protein, as involved in pathogenicity. The mutant strain, MutCl1, generated by REMI, showed an insertion in the slnCl1 gene, deficiency of the production and melanization of appressoria, as well as the absence of pathogenicity on bean leaves when compared with the wild-type strain. The slnCl1 gene encodes a histidine kinase class IV called SlnCl1 showing identity of 97% and 83% with histidine kinases from Colletotrichum orbiculare and Colletotrichum gloesporioides, respectively. RNA interference was used for silencing the histidine kinase gene and confirm slnCl1 as a pathogenicity factor. Furthermore, we identified four major genes involved in the RNA interference-mediated gene silencing in Colletotrichum spp. and demonstrated the functionality of this process in C. lindemuthianum. Silencing of the EGFP reporter gene and slnCl1 were demonstrated using qPCR. This work reports for the first time the isolation and characterization of a HK in C. lindemuthianum and the occurrence of gene silencing mediated by RNA interference in this organism, demonstrating its potential use in the functional characterization of pathogenicity genes.Item Micorriza arbuscular e a tolerância das plantas ao estresse(Revista Brasileira de Ciência do Solo, 2012-08-22) Folli-Pereira, Muriel da Silva; Meira-Haddad, Lydice Sant'Anna; Bazzolli, Denise Mara Soares; Kasuya, Maria Catarina MegumiFungos micorrízicos arbusculares (FMAs) são fungos de solo, biotróficos obrigatórios e formadores da simbiose mutualista mais comum na natureza: a micorriza arbuscular (MA). Essa associação ocorre nas raízes da maioria das plantas terrestres, promovendo melhorias no crescimento, desenvolvimento e aumento na tolerância e, ou, resistência das plantas a vários agentes ambientais adversos. Além disso, os FMAs podem ser utilizados como potenciais agentes de controle biológico de doenças de plantas. Esses fungos produzem ainda glomalina, uma proteína que desempenha papel fundamental na estabilidade do solo e bioestabilização de solos contaminados. As diferentes respostas das plantas a essa simbiose podem ser atribuídas à diversidade funcional das MAs, em função da interação FMA-planta-condições ambientais. O estabelecimento e funcionamento da MA durante as condições de estresse envolvem um complexo processo de reconhecimento e desenvolvimento, concomitantemente às alterações bioquímicas, fisiológicas e moleculares em ambos os simbiontes. Além disso, a colonização micorrízica das raízes tem impacto significativo na expressão de genes de diversas plantas que codificam proteínas presumivelmente envolvidas na tolerância ao estresse. Nesse contexto, considerando que os FMAs são essenciais no estabelecimento e adaptação das plantas em locais perturbados, nesta revisão são abordados os mecanismos fisiológicos e moleculares da associação MA responsáveis por essa adaptação e pela maior tolerância das plantas ao estresse.Item The minimal regulatory region necessary for the expression of the Penicillium griseoroseum plg1 gene(Annals of Microbiology, 2015-06) Bazzolli, Denise Mara Soares; Reis, Klédna Constância Portes; Teixeira, Janaina Aparecida; Ribon, Andréa Oliveira Barros; Queiroz, Marisa Vieira de; Araújo, Elza Fernandes deThe expression of the Penicillium griseoroseum plg1 gene is induced by citric pectin and repressed by glucose. In this work, the minimal region of the plg1 gene promoter essential for expression in pectin and sucrose plus yeast extract was identified by using constructs containing the gfp ORF under control of the plg1 gene promoter. The fragment A (283 bp) is essential for plg1 expression in sucrose plus yeast extract. Fragment B (309 bp plus 184; core promoter) was critical for expression in pectin and abolished the catabolic repression by glucose. Therefore, the fragment of 776 bp (fragment A and B) is essential for the expression of the plg1 gene in natural inducing conditions (pectin as carbon source) and in sucrose plus yeast extract. The fragment B is a promising minimal promoter usable for heterologous expression in filamentous fungi, since genes that contain it could be activated by the presence of peel from citric fruits (which contains citric pectin) and are not affected by glucose in these agricultural by-products.Item Nitrogen-fixing bacteria in Eucalyptus globulus plantations(PLOS ONE, 2014-10-23) Silva, Marliane de Cássia Soares da; Paula, Thiago de Almeida; Moreira, Bruno Coutinho; Carolino, Manuela; Cruz, Cristina; Bazzolli, Denise Mara Soares; Silva, Cynthia Canedo; Kasuya, Maria Catarina MegumiEucalypt cultivation is an important economic activity worldwide. In Portugal, Eucalyptus globulus plantations account for one-third of the total forested area. The nutritional requirements of this crop have been well studied, and nitrogen (N) is one of the most important elements required for vegetal growth. N dynamics in soils are influenced by microorganisms, such as diazotrophic bacteria (DB) that are responsible for biological nitrogen fixation (BNF), so the aim of this study was to evaluate and identity the main groups of DB in E. globulus plantations. Samples of soil and root systems were collected in winter and summer from three different Portuguese regions (Penafiel, Gavião and Odemira). We observed that DB communities were affected by season, N fertilization and moisture. Furthermore Bradyrhizobium and Burkholderia were the most prevalent genera in these three regions. This is the first study describing the dynamic of these bacteria in E. globulus plantations, and these data will likely contribute to a better understanding of the nutritional requirements of eucalypt cultivation and associated organic matter turnover.Item Organização e regulação de genes que codificam pectina liase em Penicillium griseoroseum(Universidade Federal de Viçosa, 2003-04-15) Bazzolli, Denise Mara Soares; Araújo, Elza Fernandes de; http://lattes.cnpq.br/8232568957184080Os genes plg1 e plg2, que codificam pectina liase em Penicillium griseoroseum, foram isolados e caracterizados. A região estrutural do gene plg1 possui 1341 pares de bases (pb) e é interrompida por 2 íntrons, de 101 e 115 pb, confirmados pela seqüência do cDNA. A proteína deduzida a partir da seqüência de nucleotídeos possui 374 aa, com massa molecular estimada em 40,1 KDa, um potencial sítio de glicosilação na posição N 112 e pI calculado de 9,46. O gene plg2 possui 1400 pb, sendo interrompido por quatro íntrons contendo 56, 60, 52 e 39 pb. Estes íntrons estão nas mesmas posições dos íntrons do gene pelD de Aspergillus niger, embora as seqüências de nucleotídeos sejam diferentes. A proteína deduzida possui 383 aa, massa molecular estimada de 40,5 KDa e pI de 5,55. Três possíveis sítios de glicosilação foram encontrados nas posições N 38 , N 128 e N 257 . Análise por hibridização do DNA total de P. griseoroseum e dos respectivos plasmídeos que contêm as seqüências genômicas dos genes plg1 e plg2, revelaram que estes genes estão presentes em cópias únicas no genoma do fungo. Esses resultados sugerem que P. griseoroseum possui somente dois genes que codificam pectina liase. A avaliação da regulação da expressão dos genes plg1 e plg2 foi conduzida por hibridização do RNA total e por RT-PCR. Os genes plg1 e plg2 apresentam diferente regulação em nível de transcrição. A expressão do gene plg1 é induzida por pectina cítrica e sacarose/extrato de levedura, sendo expresso ao longo de 96 horas de crescimento de P. griseoroseum. No entanto, o maior acúmulo do transcrito foi detectado com 24 horas de crescimento. A adição de glicose, frutose, galactose ou xilose no meio de cultura, reprimem a transcrição de plg1 substancialmente. O transcrito do gene plg2 foi detectado somente por RT-PCR, demonstrando que a sua expressão, mesmo induzida, é muito menor do que a de plg1. O gene plg2 foi transcrito em nível muito baixo em pectina cítrica e em pectina de maçã, não sendo transcrito em sacarose/extrato de levedura. As regiões 5' terminal dos genes plg1 e plg2 foram sequenciadas, e potenciais cis-elementos para ligação dos fatores de transcrição CreA e PacC foram identificados. Foram também detectados os cis - elementos CAAT box e TATA box. A presença dos dois primeiros cis-elementos explica a regulação de plg1, considerando que este está sujeito à repressão catabólica (CreA) e à influência do pH do meio (PacC). O gene plg1 é induzido na presença de sacarose/extrato de levedura. Análise por RT-PCR mostrou que este não foi expresso em meio contendo sacarose somente, e quantidades pequenas do transcrito foram detectadas quando o fungo foi crescido apenas em meio contendo extrato de levedura. Os resultados evidenciam que a expressão do gene plg1 depende conjuntamente de sacarose e extrato de levedura. Com o objetivo de verificar se o efeito de sacarose e extrato de levedura na expressão de plg1 depende do envolvimento do AMPc, o fungo foi crescido em meios contendo sacarose e extrato de levedura, acrescidos de substâncias que atuam na cascata de transdução de sinais via AMPc. Foi verificado que há expressão diferencial de plg1 nas diferentes substâncias testadas e nos tempos de crescimento analisados, 18 e 24 horas. A presença de cafeína e extrato de levedura provocou aumento na expressão do gene plg1 em relação ao controle contendo sacarose e extrato de levedura, e a combinação de sacarose/cafeína e extrato de levedura levou a um maior aumento. Somente sacarose e dibutiril-AMPc não promoveram o acúmulo do transcrito do gene plg1, como observado em sacarose e extrato de levedura. Este acúmulo só foi detectado na presença de extrato de levedura, o que nos leva a inferir que somente um aumento do AMPc endógeno não seria capaz de induzir a transcrição do gene plg1.Item p518, a small floR plasmid from a south american isolate of Actinobacillus pleuropneumoniae(Veterinary Microbiology, 2017-04-21) Silva, Giarlã Cunha da; Rossi, Ciro César; Santana, Mateus Ferreira; Langford, Paul R.; Bossé, Janine T.; Bazzolli, Denise Mara SoaresA small (3.9 kb) plasmid (p518), conferring resistance to florfenicol (MIC >8 μg/mL) and chloramphenicol (MIC >8 μg/mL) was isolated from an Actinobacillus pleuropneumoniae clinical isolate from Southeastern Brazil. To date, this is the smallest florfenicol resistance plasmid isolated from a member of the Pasteurellaceae. The complete nucleotide of this plasmid revealed a unique gene arrangement compared to previously reported florfenicol resistance plasmids found in other members of the Pasteurellaceae. In addition to the floR gene and a lysR gene, common to various florfenicol resistance plasmids, p518 also encodes strA and a partial strB sequence. An origin of replication (oriV) similar to that in the broad host range plasmid, pLS88, was identified in p518, and transformation into Escherichia coli MFDpir confirmed the ability to replicate in other species. Mobilisation genes appear to have been lost, with only a partial mobC sequence remaining, and attempts to transfer p518 from a conjugal donor strain (E. coli MFDpir) were not successful, suggesting this plasmid is not mobilisable. Similarly, attempts to transfer p518 into a competent A. pleuropneumoniae strain, MIDG2331, by natural transformation were also not successful. These results suggest that p518 may be only transferred by vertical descent.Item PacCl, a pH-responsive transcriptional regulator, is essential in the pathogenicity of Colletotrichum lindemuthianum, a causal agent of anthracnose in bean plants(European Journal of Plant Pathology, 2014-08-08) Nogueira, Guilherme Bicalho; Soares, Marcos Antônio; Bazzolli, Denise Mara Soares; Araújo, Elza Fernandes de; Langin, Thierry; Queiroz, Marisa Vieira deIn fungi, the expression of genes encoding proteins related to parasitism is regulated by several factors, including pH. This study reports the structural and functional characterization of the pacCl gene, which encodes the transcription factor PacC of C. lindemuthianum. The pacCl gene showed reduced expression in acidic pH, and its transcription was activated by elevated extracellular pH. The importance of this gene was demonstrated by the development of a pacC1 disruption mutant line of C. lindemuthianum. The mutant line was able to penetrate the host tissue through differentiation of primary hyphae. However, it was not able to cause maceration on the infected plant tissue. The results suggest that PacCl is a regulator of gene activation, and its expression is required for fungal growth in alkaline conditions, as well as for the transcription of genes necessary for the passage from the biotrophic to the necrotrophic phase.