Septins are a family of GTP-binding proteins, and although highly conserved throughout many eukaryotes, their functions vary across species. In Aspergillus fumigatus, the etiological agent of invasive aspergillosis, septins participate in a variety of roles such as cell wall organization of conidia, septation, and response to anti-cell wall stress. Previous studies determined that the ∆aspB strain had a greater sensitivity to anti-cell wall drugs, especially the echinocandin caspofungin, yet mechanisms behind this augmented sensitivity are unknown. We performed cell viability staining post-caspofungin exposure and found that the ∆aspA, ∆aspB, and ∆aspC strains showed significant reduction in cell viability. Concomitant with the reduced viability, deletion strains are more susceptible to caspofungin on solid media. These results indicate that the septin cytoskeleton is important for A. fumigatus survival in the presence of caspofungin. Due to the potential of improved therapeutic outcome, we followed up using a neutropenic murine model of invasive aspergillosis. Deletion of the aspB gene resulted in improved survival when treated with caspofungin when compared to the akuBKU80 wild-type or untreated ∆aspB strains. Quantitative proteomics analyses were used to find proteins involved in the septin-dependent adaptation to caspofungin. We identified four candidates with roles in cell wall integrity. Deletion of these candidate genes resulted in increase in susceptibility to caspofungin and moderate reduction in viability post drug exposure. Taken together, these data suggest that septin AspB is essential in mediating the fungistatic response to caspofungin.

The opportunistic fungus Aspergillus fumigatus has emerged as one of the most common fungal human pathogens, causing severe and usually fatal systemic infections that account for more than 200,000 cases annually with mortality rates usually exceeding 50%. During infection, the virulence of A. fumigatus highly depends on its capacity to rapidly respond to external stress encounters in the human niche, such as the host immunological response and the activity of antifungal drugs. The echinocandin, caspofungin, is one of most commonly used antifungal drugs to treat intolerant or refractive patients suffering from invasive aspergillosis. Caspofungin disrupts the catalytic subunit of the β-1,3-glucan synthase complex, Fks1, resulting in the reduced production of the main cell wall component of A. fumigatus, the polysaccharide β-1,3-glucan. Despite its clinical relevance in patients with aspergillosis, caspofungin displays attenuated activity at high concentrations, a phenomenon known as ‘the paradoxical effect’. Little is known about the paradoxical growth of A. fumigatus during caspofungin treatment. Therefore, in this thesis, I investigated the key cellular and molecular responses of A. fumigatus upon caspofungin treatment, particularly during paradoxical growth by live-cell imaging. High-resolution confocal live-cell microscopy revealed that treatment with either low (0.5 µg/ml) or high (4 µg/ml) concentrations of caspofungin for 36 h caused similar abnormalities in A. fumigatus, including wider, hyperbranched hyphae, increased septation and repeated hyphal tip lysis. Regenerative intrahyphal growth occurred as a rapid adaptation to the lytic effects of caspofungin on hyphal tips and the dynamic relocation of Fks1 to vacuoles was a key feature observed in response to caspofungin treatment. The reduced amount of β-1,3-glucan resulting from caspofungin treatment was compensated by increased α-1,3-glucan and chitin content in mature hyphal tips. Interestingly, all lysed cells recovered by regenerative intrahyphal growth. However, after 48 h treatment, only cells exposed to high caspofungin concentrations developed paradoxical growth in leading hyphae. This response was associated with a relocalization of Fks1 at hyphal tips. Consistently, cells undergoing paradoxical growth showed normal morphology and ceased to undergo cell lysis, as well as having a normal content of β-1,3-glucan and α-1,3-glucan but not chitin, which remained high. Notably, the localization of the regulatory subunit of the β-1,3-glucan synthase complex, Rho1, was unaffected by caspofungin, but it was required for the development of paradoxical growth. Interestingly, the gene expression of the β-1,3-glucan synthase complex was downregulated by caspofungin treatment. In addition, caspofungin activity induced the nuclear translocation of the Ca+2 regulated transcription factor CrzA to nuclei and only hyphal tip cells in which this translocation occurred underwent cell lysis. Finally, similarly high concentrations of caspofungin also induced paradoxical growth of Aspergillus fumigatus during human A549 alveolar cell invasion. This thesis outlines several critical adaptations that occur at the cellular, subcellular and molecular levels at different times during exposure to high and low concentration of caspofungin.

Les entérocoques, sont des bactéries commensales du tube digestif de l’homme et des animaux, mais certaines espèces, comme Enterococcus faecium, sont aussi des pathogènes opportunistes majeurs souvent multi-résistants aux antibiotiques. Nous avons étudié l’impact de molécules non antibiotiques utilisées dans les unités de soins intensifs, sur la virulence et la résistance d’une souche clinique de E. faecium par une approche microscopique, une analyse du peptidoglycane et une analyse trancriptomique. Ce travail nous a permis de décrire l’effet antibactérien de la caspofungine, molécule antifongique. Nous avons également étudié deux nouveaux mécanismes de résistance chez E. faecium i) la résistance aux lincosamides, streptogramines A et pleuromutilines (phénotype LSAP) par la mutation ponctuelle d’un gène codant pour une protéine ABC de type II. ii) la diminution de sensibilité à la tigécycline due à l’apparition de mutations au sein du gène rpsJ codant pour la protéine ribosomale S10 jouant un rôle dans la formation de la sous-unité 30S du ribosome. Enfin, nous avons participé à une étude sur Enterococcus hirae, espèce qui induirait la production de sous-populations de lymphocytes T permettant d’augmenter l’efficacité in vivo du cyclophosphamide (CTX) dans le traitement de tumeurs chez la souris. Une caractérisation des facteurs de virulence, de la résistance aux antibiotiques et du pouvoir de colonisation d’une collection de souches d’E. hirae a été menée, de même qu’une étude transcriptomique en présence de CTX et une étude de génomique comparative, afin de caractériser cette espèce dans l’optique de son utilisation comme oncobiotique. / Enterococci are commensal bacteria of the human and animal gastrointestinal tract, but some species as Enterococcus faecium, are also major opportunistic pathogens often multiply resistant to antibiotics. We studied the impact of non-antibiotic molecules widely used in intensive care units on fitness, virulence and resistance of a clinical isolate of E. faecium belonging to CC17 by a microscopic approach, a peptidoglycan analysis and a trancriptomic analysis. This work allowed us to demonstratethe antimicrobial effect of caspofungin, molecule known for its antifungal activity. We also characterized two novel resistance mechanisms found in E. faecium: i) resistance to lincosamides, streptogramines A and pleuromutilins (LSAP phenotype) linked to a point mutation in a gene encoding for a type-II ABC protein. ii) decreased susceptibility to tigecycline due to the occurrence of mutations within the rpsJ gene encoding the S10 ribosomal protein that plays a role in 30S ribosomal subunit formation. Finally, we participated to a study concerning Enterococcus hirae, species that induces the production of sub-populations of T lymphocytes that increase the in vivo efficacy of cyclophosphamide (CTX) in the treatment of murine tumors. A characterization of the virulence factors, antibiotic resistance profiles and colonization capacities of a collection of E. hirae isolates was carried out. A transcriptomic study in the presence of CTX and a comparative genomic study were also done, in order to characterize this species in view of its use as an oncobiotic.

No description available.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED, APS-I) is exceptionally common in Finland. Most patients have chronic oral candidiasis since childhood. Thus, most patients receive repeated courses of antifungals throughout their life. Eleven of our patients (31.4%) have become colonized with Candida albicans with decreased sensitivity to fluconazole. A total of 43 isolates of C. albicans from 23 APECED patients isolated during the years 1994 to 2004 were divided into 2 groups: fluconazole-susceptible dose-dependent (MIC, 16-32 μg/mL, 18 isolates) and fluconazole-susceptible (MIC ≤8 μg/mL, 25 isolates) groups. Antifungal activity of amphotericin B, echinocandins, and azoles was determined by the Clinical and Laboratory Standards Institute M27-A2 methodology. All isolates were highly susceptible to amphotericin B and echinocandins. Posaconazole and voriconazole were active against all isolates. Our data suggest that topical amphotericin B could continue to be a safe and active drug for daily administration for APECED patients. Posaconazole, voriconazole, and echinocandins may be useful in some complicated cases.

No description available.

O oomiceto aquático Pythium insidiosum, classificado no Reino Stramenipila, é o agente etiológico da pitiose, uma doença crônica, piogranulomatosa, que acomete eqüinos, caninos, felinos, bovinos, ovinos e humanos que habitam regiões tropicais e subtropicais. Diversos protocolos para o tratamento da enfermidade têm sido utilizados, incluindo terapia com antifúngicos, cirurgia e imunoterapia. O presente estudo objetivou avaliar a suscetibilidade in vitro de 27 isolados clínicos de Pythium insidiosum ao acetato de caspofungina, bem como correlacionar os resultados obtidos in vitro com a resposta da terapêutica in vivo e comparar a eficácia de dois tratamentos, acetato de caspofungina e imunoterapia, utilizando coelhos como modelo experimental. Vinte e seis isolados de Pythium insidiosum provenientes de casos clínicos de pitiose em animais no Brasil (24 eqüinos, 01 canino e 01 ovino) e um isolado ATCC (58637) foram avaliados neste estudo. Os testes in vitro foram desenvolvidos utilizando-se a macrotécnica em caldo seguindo o protocolo internacional M38-A do CLSI. O inóculo consistiu de uma suspensão de 2-3x103 zoósporos de Pythium insidiosum diluído 1:10 em caldo RPMI. As concentrações finais do acetato de caspofungina variaram de 0,25 – 128 μg/mL. A leitura dos CIMs foi visual, considerando-se o crescimento ou não de hifas em 24 horas de incubação a 370C, sendo adotados 3 critérios de leitura: CIM0; CIM1 e CIM2 (100%, 90% e 50% de inibição de crescimento, respectivamente), assim como também foi determinada a concentração fungicida mínima. No ensaio in vivo, 15 coelhos inoculados subcutaneamente com 20.000 zoósporos de Pythium insidiosum foram divididos em 3 grupos de 5 animais (grupo 1, controle; grupo 2, tratado com imunoterápico Pitium Vac® e grupo 3, tratado com acetato de caspofungina). Os tratamentos iniciaram-se 25 dias após a inoculação e consitiram de: 1) 8 doses de imunoterápico administradas em intervalos de 14 dias; 2) 1 mg/kg/dia de acetato de caspofungina durante 20 dias consecutivos. Dezoito semanas após o início do experimento, os animais foram necropsiados e fragmentos de lesões foram coletados para análise histopatológica e morfométrica. Quatorze isolados (51,8%) evidenciaram CIM0 de 64 μg/mL e 24 (88,8%) CIM1 com variação de ≥ 8μg/mL a 64 μg/mL. Na determinação da concentração fungicida mínima, 17 (62,9%) amostras requereram 64 μg/mL. Os animais de ambos os tratamentos apresentaram redução da área de lesões, quando comparados aos animais do grupo controle (P<0.05). As áreas de lesões dos coelhos tratados com acetato de caspofungina evidenciaram redução durante o tratamento, porém rapidamente retornaram a progredir quando a administração do fármaco foi suspensa. O aspecto histológico das lesões foi similar entre os grupos estudados e a avaliação morfométrica evidenciou que os animais dos grupos 2 e 3 apresentaram menor quantidade de hifas nas áreas de necrose (P<0.05). Os resultados obtidos evidenciam que, embora não tenha havido diferença entre os tratamentos avaliados, a imunoterapia, em função de seu custo, continua sendo a melhor alternativa para o tratamento da pitiose. A ocorrência de altas CIMs associada a falta de atividade fungicida do acetato de caspofungina observados neste estudo, sugerem que Pythium insidiosum é pouco suscetível a este antifúngico. / For the in vivo assay, fifteen rabbits were subcutaneously inoculated with 20,000 Pythium insidiosum zoospores and were divided into 3 groups of 5 animals (group 1, control; group 2, treated with Pitium Vac® immunotherapic; and group 3, treated with caspofungin acetate). The treatments were started 25 days after the inoculation, and consisted of: 1) 8 doses of the immunotherapic administered at 14-day intervals; and 2) 1mg/kg/day of caspofungin acetate during 20 consecutive days. The animals were necropsied eighteen weeks after the start of the experiment, and lesion fragments were collected for histopathologic and morphometric analyses. Fourteen isolates (51.8%) had an MIC0 of 64 μg/mL, and 24 (88.8%) had an MIC1 that varied between ≥ 8μg/mL and 64 μg/mL. When subjected to the minimum fungicidal concentration assay, 17 (62.9%) samples required 64 μg/mL. The animals in both treatment groups displayed smaller lesion sizes compared to the animals of group control (P<0.05). The subcutaneous lesion areas of rabbits treated with caspofungin acetate exhibited a reduction in their progression during the treatment. However, lesions quickly resumed growth when the administration of the drug was suspended. The histological aspect of the lesions was similar between the groups under study, and the morphometric evaluation showed that the animals in groups 2 and 3 had lower amounts of hyphae in necrotic areas (P<0.05). The results obtained indicate that, even though the treatments did not differ significantly, the immunotherapic treatment is still the best alternative to treat pythiosis. In addition, the high MICs and lack of fungicidality of caspofungin acetate suggest that Pythium insidiosum is poorly susceptible to this antifungal drug.

O oomiceto aquático Pythium insidiosum, classificado no Reino Stramenipila, é o agente etiológico da pitiose, uma doença crônica, piogranulomatosa, que acomete eqüinos, caninos, felinos, bovinos, ovinos e humanos que habitam regiões tropicais e subtropicais. Diversos protocolos para o tratamento da enfermidade têm sido utilizados, incluindo terapia com antifúngicos, cirurgia e imunoterapia. O presente estudo objetivou avaliar a suscetibilidade in vitro de 27 isolados clínicos de Pythium insidiosum ao acetato de caspofungina, bem como correlacionar os resultados obtidos in vitro com a resposta da terapêutica in vivo e comparar a eficácia de dois tratamentos, acetato de caspofungina e imunoterapia, utilizando coelhos como modelo experimental. Vinte e seis isolados de Pythium insidiosum provenientes de casos clínicos de pitiose em animais no Brasil (24 eqüinos, 01 canino e 01 ovino) e um isolado ATCC (58637) foram avaliados neste estudo. Os testes in vitro foram desenvolvidos utilizando-se a macrotécnica em caldo seguindo o protocolo internacional M38-A do CLSI. O inóculo consistiu de uma suspensão de 2-3x103 zoósporos de Pythium insidiosum diluído 1:10 em caldo RPMI. As concentrações finais do acetato de caspofungina variaram de 0,25 – 128 μg/mL. A leitura dos CIMs foi visual, considerando-se o crescimento ou não de hifas em 24 horas de incubação a 370C, sendo adotados 3 critérios de leitura: CIM0; CIM1 e CIM2 (100%, 90% e 50% de inibição de crescimento, respectivamente), assim como também foi determinada a concentração fungicida mínima. No ensaio in vivo, 15 coelhos inoculados subcutaneamente com 20.000 zoósporos de Pythium insidiosum foram divididos em 3 grupos de 5 animais (grupo 1, controle; grupo 2, tratado com imunoterápico Pitium Vac® e grupo 3, tratado com acetato de caspofungina). Os tratamentos iniciaram-se 25 dias após a inoculação e consitiram de: 1) 8 doses de imunoterápico administradas em intervalos de 14 dias; 2) 1 mg/kg/dia de acetato de caspofungina durante 20 dias consecutivos. Dezoito semanas após o início do experimento, os animais foram necropsiados e fragmentos de lesões foram coletados para análise histopatológica e morfométrica. Quatorze isolados (51,8%) evidenciaram CIM0 de 64 μg/mL e 24 (88,8%) CIM1 com variação de ≥ 8μg/mL a 64 μg/mL. Na determinação da concentração fungicida mínima, 17 (62,9%) amostras requereram 64 μg/mL. Os animais de ambos os tratamentos apresentaram redução da área de lesões, quando comparados aos animais do grupo controle (P<0.05). As áreas de lesões dos coelhos tratados com acetato de caspofungina evidenciaram redução durante o tratamento, porém rapidamente retornaram a progredir quando a administração do fármaco foi suspensa. O aspecto histológico das lesões foi similar entre os grupos estudados e a avaliação morfométrica evidenciou que os animais dos grupos 2 e 3 apresentaram menor quantidade de hifas nas áreas de necrose (P<0.05). Os resultados obtidos evidenciam que, embora não tenha havido diferença entre os tratamentos avaliados, a imunoterapia, em função de seu custo, continua sendo a melhor alternativa para o tratamento da pitiose. A ocorrência de altas CIMs associada a falta de atividade fungicida do acetato de caspofungina observados neste estudo, sugerem que Pythium insidiosum é pouco suscetível a este antifúngico. / For the in vivo assay, fifteen rabbits were subcutaneously inoculated with 20,000 Pythium insidiosum zoospores and were divided into 3 groups of 5 animals (group 1, control; group 2, treated with Pitium Vac® immunotherapic; and group 3, treated with caspofungin acetate). The treatments were started 25 days after the inoculation, and consisted of: 1) 8 doses of the immunotherapic administered at 14-day intervals; and 2) 1mg/kg/day of caspofungin acetate during 20 consecutive days. The animals were necropsied eighteen weeks after the start of the experiment, and lesion fragments were collected for histopathologic and morphometric analyses. Fourteen isolates (51.8%) had an MIC0 of 64 μg/mL, and 24 (88.8%) had an MIC1 that varied between ≥ 8μg/mL and 64 μg/mL. When subjected to the minimum fungicidal concentration assay, 17 (62.9%) samples required 64 μg/mL. The animals in both treatment groups displayed smaller lesion sizes compared to the animals of group control (P<0.05). The subcutaneous lesion areas of rabbits treated with caspofungin acetate exhibited a reduction in their progression during the treatment. However, lesions quickly resumed growth when the administration of the drug was suspended. The histological aspect of the lesions was similar between the groups under study, and the morphometric evaluation showed that the animals in groups 2 and 3 had lower amounts of hyphae in necrotic areas (P<0.05). The results obtained indicate that, even though the treatments did not differ significantly, the immunotherapic treatment is still the best alternative to treat pythiosis. In addition, the high MICs and lack of fungicidality of caspofungin acetate suggest that Pythium insidiosum is poorly susceptible to this antifungal drug.

O oomiceto aquático Pythium insidiosum, classificado no Reino Stramenipila, é o agente etiológico da pitiose, uma doença crônica, piogranulomatosa, que acomete eqüinos, caninos, felinos, bovinos, ovinos e humanos que habitam regiões tropicais e subtropicais. Diversos protocolos para o tratamento da enfermidade têm sido utilizados, incluindo terapia com antifúngicos, cirurgia e imunoterapia. O presente estudo objetivou avaliar a suscetibilidade in vitro de 27 isolados clínicos de Pythium insidiosum ao acetato de caspofungina, bem como correlacionar os resultados obtidos in vitro com a resposta da terapêutica in vivo e comparar a eficácia de dois tratamentos, acetato de caspofungina e imunoterapia, utilizando coelhos como modelo experimental. Vinte e seis isolados de Pythium insidiosum provenientes de casos clínicos de pitiose em animais no Brasil (24 eqüinos, 01 canino e 01 ovino) e um isolado ATCC (58637) foram avaliados neste estudo. Os testes in vitro foram desenvolvidos utilizando-se a macrotécnica em caldo seguindo o protocolo internacional M38-A do CLSI. O inóculo consistiu de uma suspensão de 2-3x103 zoósporos de Pythium insidiosum diluído 1:10 em caldo RPMI. As concentrações finais do acetato de caspofungina variaram de 0,25 – 128 μg/mL. A leitura dos CIMs foi visual, considerando-se o crescimento ou não de hifas em 24 horas de incubação a 370C, sendo adotados 3 critérios de leitura: CIM0; CIM1 e CIM2 (100%, 90% e 50% de inibição de crescimento, respectivamente), assim como também foi determinada a concentração fungicida mínima. No ensaio in vivo, 15 coelhos inoculados subcutaneamente com 20.000 zoósporos de Pythium insidiosum foram divididos em 3 grupos de 5 animais (grupo 1, controle; grupo 2, tratado com imunoterápico Pitium Vac® e grupo 3, tratado com acetato de caspofungina). Os tratamentos iniciaram-se 25 dias após a inoculação e consitiram de: 1) 8 doses de imunoterápico administradas em intervalos de 14 dias; 2) 1 mg/kg/dia de acetato de caspofungina durante 20 dias consecutivos. Dezoito semanas após o início do experimento, os animais foram necropsiados e fragmentos de lesões foram coletados para análise histopatológica e morfométrica. Quatorze isolados (51,8%) evidenciaram CIM0 de 64 μg/mL e 24 (88,8%) CIM1 com variação de ≥ 8μg/mL a 64 μg/mL. Na determinação da concentração fungicida mínima, 17 (62,9%) amostras requereram 64 μg/mL. Os animais de ambos os tratamentos apresentaram redução da área de lesões, quando comparados aos animais do grupo controle (P<0.05). As áreas de lesões dos coelhos tratados com acetato de caspofungina evidenciaram redução durante o tratamento, porém rapidamente retornaram a progredir quando a administração do fármaco foi suspensa. O aspecto histológico das lesões foi similar entre os grupos estudados e a avaliação morfométrica evidenciou que os animais dos grupos 2 e 3 apresentaram menor quantidade de hifas nas áreas de necrose (P<0.05). Os resultados obtidos evidenciam que, embora não tenha havido diferença entre os tratamentos avaliados, a imunoterapia, em função de seu custo, continua sendo a melhor alternativa para o tratamento da pitiose. A ocorrência de altas CIMs associada a falta de atividade fungicida do acetato de caspofungina observados neste estudo, sugerem que Pythium insidiosum é pouco suscetível a este antifúngico. / For the in vivo assay, fifteen rabbits were subcutaneously inoculated with 20,000 Pythium insidiosum zoospores and were divided into 3 groups of 5 animals (group 1, control; group 2, treated with Pitium Vac® immunotherapic; and group 3, treated with caspofungin acetate). The treatments were started 25 days after the inoculation, and consisted of: 1) 8 doses of the immunotherapic administered at 14-day intervals; and 2) 1mg/kg/day of caspofungin acetate during 20 consecutive days. The animals were necropsied eighteen weeks after the start of the experiment, and lesion fragments were collected for histopathologic and morphometric analyses. Fourteen isolates (51.8%) had an MIC0 of 64 μg/mL, and 24 (88.8%) had an MIC1 that varied between ≥ 8μg/mL and 64 μg/mL. When subjected to the minimum fungicidal concentration assay, 17 (62.9%) samples required 64 μg/mL. The animals in both treatment groups displayed smaller lesion sizes compared to the animals of group control (P<0.05). The subcutaneous lesion areas of rabbits treated with caspofungin acetate exhibited a reduction in their progression during the treatment. However, lesions quickly resumed growth when the administration of the drug was suspended. The histological aspect of the lesions was similar between the groups under study, and the morphometric evaluation showed that the animals in groups 2 and 3 had lower amounts of hyphae in necrotic areas (P<0.05). The results obtained indicate that, even though the treatments did not differ significantly, the immunotherapic treatment is still the best alternative to treat pythiosis. In addition, the high MICs and lack of fungicidality of caspofungin acetate suggest that Pythium insidiosum is poorly susceptible to this antifungal drug.

Aspergillus fumigatus é um fungo saprófita e um dos principais fungos patogênicos humanos. Os seus conídios são inalados e chegam ao pulmão, onde se tornam ativos e germinam, dando origem a uma doença conhecida como aspergilose. A aspergilose é um conjunto de formas clínicas que apresenta grande risco, principalmente, para indivíduos imunossuprimidos. A sinalização de cálcio desempenha importante papel na regulação de diversas respostas fisiológicas, já que o Ca2+ corresponde a um mensageiro secundário que participa de diferentes processos biológicos, como ciclo celular, diferenciação, ou homeostase. Além disso, as equinocandinas, como a caspofungina, são antifúngicos cujo alvo é a parede celular do fungo. Esses agentes reduzem a concentração total de 1,3-?-D-glucanos na parede da célula, através da inibição da atividade da 1,3-?-glucano sintase. A inibição da síntese de componentes da parede celular através de drogas antifúngicas pode ser um alvo importante contra infecções causadas por A. fumigatus. Através de um screening de fatores de transcrição, foram identificados genes pertinentes a esses processos. A deleção do gene nsdC resultou em maior sensibilidade ao CaCl2, EGTA, Congo Red, Nikkomycin Z, Calcoflúor White, Caspofungina (efeito paradoxical reduzido), 44oC, Menadiona e T-butil hidroperóxido. Além disso, o mutante nulo ?nsdC mostrou-se mais resistente ao Sorbitol e à Ciclosporina. O fator de transcrição NsdC parece estar envolvido na via de sinalização de cálcio, por ter sua expressão alterada na ausência do fator de transcrição CrzA. Além disso, NsdC mostrou-se importante em processos relacionados à parede celular, pois sua deleção leva à formação de hifas mais ramificadas e desorganizadas, e parede celular mais espessa. Esse fator de transcrição aparenta, ainda, ser repressor da reprodução assexual. Isso se deve ao fato de o mutante nulo ?nsdC apresentar conídios em meio líquido e aumento signficativo da expressão de brlA. Ademais, a proteína NsdC encontra-se majoritariamente presente no núcleo, após tratamento com CaCl2. Outros mutantes de fatores de transcrição, que apresentam sensibilidade à Caspofungina, foram identificados: ?cbfA, ?nctA, ?nctB e ?nctC. Algumas evidências apontam que NctA e NctB fazem parte de um mesmo complexo. Já NctC parece estar relacionado a estresses de temperatura e osmótico, sendo importante para a virulência em A. fumigatus. Portanto, mais estudos são necessários a fim de melhor compreender os papéis desses genes, podendo ser importantes para trazer maiores informações acerca de potenciais alvos terapêuticos no tratamento de aspergilose. / Aspergillus fumigatus is a saprophytic fungus and one of the main human pathogenic fungi. Their conidia are inhaled and reach the lungs, where they activate and germinate, and can trigger aspergillosis. Aspergillosis clinical forms presents great risk, mainly for the immunosuppressed patients. Calcium signaling has important role in physiological responses. Calcium corresponds to a secondary messenger that participates in different biological processes, such as cell cycle, differentiation, or homeostasis. In addition, echinocandins, such as caspofungin, are antifungal drugs that target the fungal cell wall. These agents reduce the total concentration of 1,3-?- D-glucans on the cell wall, by inhibiting the activity of 1,3-?-glucan synthase. Inhibition of the synthesis of cell wall components through antifungal drugs may be an important target against infections caused by A. fumigatus. Screening of transcription factors genes have been identified. The deletion of the nsdC gene results from increased sensitivity to CaCl2, EGTA, Congo Red, Nikkomycin Z, Calcofluor White, Caspofungin (reduced paradoxical effect), 44C, Menadione and Tbutyl hydroperoxide. In addition, the ?nsdC null mutant is more resistant to Sorbitol and Cyclosporin. The transcription factor NsdC seems to be involved in the signaling of calcium, and its expression is altered in the absence of the CrzA transcription factor. In addition, NsdC has been shown to be important in processes related to the cell wall, since its deletion leads to the formation of more branched and disorganized hyphae and thicker cell wall. This transcription factor also appears to be a repressor of asexual reproduction. This is due to the fact that the null mutant ?nsdC produces conidia in liquid medium and leads to a significant increase in the expression of brlA. In addition, the NsdC protein is mostly present in the nucleus, after treatment with CaCl2. Other mutants of transcription factors sensitivity to Caspofungin have been identified: ?cbfA, ?nctA, ?nctB and ?nctC. Some evidence indicates that NctA and NctB are part of the same complex. Besides that, NctC seems to be related to temperature and osmotic stresses, being important for virulence in A. fumigatus. Therefore, more studies are needed in order to better understand the roles of these genes and may be important in bringing greater information about potential therapeutic targets in the treatment of aspergillosis.