RESUMEN
Land-use conversion changes soil properties and their microbial communities, which, combined with the overuse of antibiotics in human and animal health, promotes the expansion of the soil resistome. In this context, we aimed to profile the resistome and the microbiota of soils under different land practices. We collected eight soil samples from different locations in the countryside of São Paulo (Brazil), assessed the community profiles based on 16S rRNA sequencing, and analyzed the soil metagenomes based on shotgun sequencing. We found differences in the communities' structures and their dynamics that were correlated with land practices, such as the dominance of Staphylococcus and Bacillus genera in agriculture fields. Additionally, we surveyed the abundance and diversity of antibiotic resistance genes (ARGs) and virulence factors (VFs) across studied soils, observing a higher presence and homogeneity of the vanRO gene in livestock soils. Moreover, three ß-lactamases were identified in orchard and urban square soils. Together, our findings reinforce the importance and urgency of AMR surveillance in the environment, especially in soils undergoing deep land-use transformations, providing an initial exploration under the One Health approach of environmental levels of resistance and profiling soil communities.
RESUMEN
The current treatment of leishmaniasis is based on a few drugs that present several drawbacks, such as high toxicity, difficult administration route, and low efficacy. These disadvantages raise the necessity to develop novel antileishmanial compounds allied with a comprehensive understanding of their mechanisms of action. Here, we elucidate the probable mechanism of action of the antileishmanial binuclear cyclopalladated complex [Pd(dmba)(µ-N3)]2 (CP2) in Leishmania amazonensis. CP2 causes oxidative stress in the parasite, resulting in disruption of mitochondrial Ca2+ homeostasis, cell cycle arrest at the S-phase, increasing the reactive oxygen species (ROS) production and overexpression of stress-related and cell detoxification proteins, and collapsing the Leishmania mitochondrial membrane potential, and promotes apoptotic-like features in promastigotes, leading to necrosis, or directs programmed cell death (PCD)-committed cells toward necrotic-like destruction. Moreover, CP2 reduces the parasite load in both liver and spleen in Leishmania infantum-infected hamsters when treated for 15 days with 1.5 mg/kg body weight/day CP2, expanding its potential application in addition to the already known effectiveness on cutaneous leishmaniasis for the treatment of visceral leishmaniasis, showing the broad spectrum of action of this cyclopalladated complex. The data presented here bring new insights into the CP2 molecular mechanisms of action, assisting the promotion of its rational modification to improve both safety and efficacy.
Asunto(s)
Antiprotozoarios , Leishmania infantum , Leishmaniasis Cutánea , Animales , Antiprotozoarios/uso terapéutico , Calcio/metabolismo , Muerte Celular , Leishmaniasis Cutánea/tratamiento farmacológico , Macrófagos , Ratones , Ratones Endogámicos BALB C , MitocondriasRESUMEN
DNA topoisomerases are enzymes that modulate DNA topology. Among them, topoisomerase 3α is engaged in genomic maintenance acting in DNA replication termination, sister chromatid separation, and dissolution of recombination intermediates. To evaluate the role of this enzyme in Trypanosoma cruzi, the etiologic agent of Chagas disease, a topoisomerase 3α knockout parasite (TcTopo3α KO) was generated, and the parasite growth, as well as its response to several DNA damage agents, were evaluated. There was no growth alteration caused by the TcTopo3α knockout in epimastigote forms, but a higher dormancy rate was observed. TcTopo3α KO trypomastigote forms displayed reduced invasion rates in LLC-MK2 cells when compared with the wild-type lineage. Amastigote proliferation was also compromised in the TcTopo3α KO, and a higher number of dormant cells was observed. Additionally, TcTopo3α KO epimastigotes were not able to recover cell growth after gamma radiation exposure, suggesting the involvement of topoisomerase 3α in homologous recombination. These parasites were also sensitive to drugs that generate replication stress, such as cisplatin (Cis), hydroxyurea (HU), and methyl methanesulfonate (MMS). In response to HU and Cis treatments, TcTopo3α KO parasites showed a slower cell growth and was not able to efficiently repair the DNA damage induced by these genotoxic agents. The cell growth phenotype observed after MMS treatment was similar to that observed after gamma radiation, although there were fewer dormant cells after MMS exposure. TcTopo3α KO parasites showed a population with sub-G1 DNA content and strong γH2A signal 48 h after MMS treatment. So, it is possible that DNA-damaged cell proliferation due to the absence of TcTopo3α leads to cell death. Whole genome sequencing of MMS-treated parasites showed a significant reduction in the content of the multigene families DFG-1 and RHS, and also a possible erosion of the sub-telomeric region from chromosome 22, relative to non-treated knockout parasites. Southern blot experiments suggest telomere shortening, which could indicate genomic instability in TcTopo3α KO cells owing to MMS treatment. Thus, topoisomerase 3α is important for homologous recombination repair and replication stress in T. cruzi, even though all the pathways in which this enzyme participates during the replication stress response remains elusive.
RESUMEN
DNA topoisomerases are enzymes that modulate DNA topology. Among them, topoisomerase 3α is engaged in genomic maintenance acting in DNA replication termination, sister chromatid separation, and dissolution of recombination intermediates. To evaluate the role of this enzyme in Trypanosoma cruzi, the etiologic agent of Chagas disease, a topoisomerase 3α knockout parasite (TcTopo3α KO) was generated, and the parasite growth, as well as its response to several DNA damage agents, were evaluated. There was no growth alteration caused by the TcTopo3α knockout in epimastigote forms, but a higher dormancy rate was observed. TcTopo3α KO trypomastigote forms displayed reduced invasion rates in LLC-MK2 cells when compared with the wild-type lineage. Amastigote proliferation was also compromised in the TcTopo3α KO, and a higher number of dormant cells was observed. Additionally, TcTopo3α KO epimastigotes were not able to recover cell growth after gamma radiation exposure, suggesting the involvement of topoisomerase 3α in homologous recombination. These parasites were also sensitive to drugs that generate replication stress, such as cisplatin (Cis), hydroxyurea (HU), and methyl methanesulfonate (MMS). In response to HU and Cis treatments, TcTopo3α KO parasites showed a slower cell growth and was not able to efficiently repair the DNA damage induced by these genotoxic agents. The cell growth phenotype observed after MMS treatment was similar to that observed after gamma radiation, although there were fewer dormant cells after MMS exposure. TcTopo3α KO parasites showed a population with sub-G1 DNA content and strong γH2A signal 48 h after MMS treatment. So, it is possible that DNA-damaged cell proliferation due to the absence of TcTopo3α leads to cell death. Whole genome sequencing of MMS-treated parasites showed a significant reduction in the content of the multigene families DFG-1 and RHS, and also a possible erosion of the sub-telomeric region from chromosome 22, relative to non-treated knockout parasites. Southern blot experiments suggest telomere shortening, which could indicate genomic instability in TcTopo3α KO cells owing to MMS treatment. Thus, topoisomerase 3α is important for homologous recombination repair and replication stress in T. cruzi, even though all the pathways in which this enzyme participates during the replication stress response remains elusive.
RESUMEN
In Trypanosoma cruzi, the etiologic agent of Chagas disease, Rad51 (TcRad51) is a central enzyme for homologous recombination. Here we describe the different roles of TcRad51 in DNA repair. Epimastigotes of T. cruzi overexpressing TcRAD51 presented abundant TcRad51-labeled foci before gamma irradiation treatment, and a faster growth recovery when compared to single-knockout epimastigotes for RAD51. Overexpression of RAD51 also promoted increased resistance against hydrogen peroxide treatment, while the single-knockout epimastigotes for RAD51 exhibited increased sensitivity to this oxidant agent, which indicates a role for this gene in the repair of DNA oxidative lesions. In contrast, TcRad51 was not involved in the repair of crosslink lesions promoted by UV light and cisplatin treatment. Also, RAD51 single-knockout epimastigotes showed a similar growth rate to that exhibited by wild-type ones after treatment with hydroxyurea, but an increased sensitivity to methyl methane sulfonate. Besides its role in epimastigotes, TcRad51 is also important during mammalian infection, as shown by increased detection of T. cruzi cells overexpressing RAD51, and decreased detection of single-knockout cells for RAD51, in both fibroblasts and macrophages infected with amastigotes. Besides that, RAD51-overexpressing parasites infecting mice also presented increased infectivity and higher resistance against benznidazole. We thus show that TcRad51 is involved in the repair of DNA double strands breaks and oxidative lesions in two different T. cruzi developmental stages, possibly playing an important role in the infectivity of this parasite.
Asunto(s)
Roturas del ADN de Doble Cadena , Reparación del ADN , Proteínas Protozoarias/metabolismo , Recombinasa Rad51/metabolismo , Trypanosoma cruzi/enzimología , Trypanosoma cruzi/genética , Animales , Enfermedad de Chagas/parasitología , Roturas del ADN de Doble Cadena/efectos de la radiación , Reparación del ADN/efectos de la radiación , Humanos , Masculino , Ratones , Estrés Oxidativo , Proteínas Protozoarias/genética , Recombinasa Rad51/genética , Trypanosoma cruzi/metabolismo , Trypanosoma cruzi/efectos de la radiación , Rayos UltravioletaRESUMEN
Here, we report that the Neurospora crassa FLB-3 protein, the ortholog of the Aspergillus nidulans FlbC transcription factor, is required for developmental control. Deletion of flb-3 leads to changes in hyphae morphology and affects sexual and asexual development. We identified, as putative FLB-3 targets, the N. crassa aba-1, wet-1 and vos-1 genes, orthologs of the ones involved in A. nidulans asexual development and that work downstream of FlbC (abaA, wetA and vosA). In N. crassa, these three genes require FLB-3 for proper expression; however, they appear not to be required for normal development, as demonstrated by gene expression analyses during vegetative growth and asexual development. Moreover, mutant strains in the three genes conidiate well and produce viable conidia. We also determined FLB-3 DNA-binding preferences via protein-binding microarrays (PBMs) and demonstrated by chromatin immunoprecipitation (ChIP) that FLB-3 binds the aba-1, wet-1 and vos-1 promoters. Our data support an important role for FLB-3 in N. crassa development and highlight differences between the regulatory pathways controlled by this transcription factor in different fungal species.
Asunto(s)
Proteínas Fúngicas/fisiología , Neurospora crassa/crecimiento & desarrollo , Factores de Transcripción/fisiología , Proteínas Fúngicas/genética , Regulación del Desarrollo de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Hifa/genética , Hifa/crecimiento & desarrollo , Neurospora crassa/genética , Esporas Fúngicas/genética , Esporas Fúngicas/crecimiento & desarrollo , Factores de Transcripción/genéticaRESUMEN
Microorganisms have the ability to adapt and respond to different environmental conditions, whether they are stressful or not. Although the detection and/or responding mechanisms are often unknown, a large number of proteins may participate in signal transduction pathways involved in environmental stimulus to induce physiological and cellular events. Here, we examine the important role in cell homeostasis that extracellular pH plays in different fungi, and summarize the recent data reported in distinct organisms, by comparing them to the well-characterized mechanisms firstly described in Aspergillus and yeast. While most of the knowledge regarding the cellular processes triggered by the pH signaling pathway is based on the work in these two organisms, new data have been emerging in a diverse group of filamentous fungi, namely the involvement of this signaling pathway in metabolism and fungal pathogenicity. In this review, we present the major aspects of the pH signaling pathway in different model organisms, focusing on the protein components and the biological processes influenced by this pathway. In particular, we discuss novel cellular processes regulated by this pathway in the fungus Neurospora crassa. The diversity of functional processes that are affected under pH stress highlights how broadly this condition impacts on basic cellular processes in fungi and reveals how divergent fungal species are.
Asunto(s)
Neurospora crassa/metabolismo , Transducción de Señal , Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica , Genes Fúngicos , Concentración de Iones de Hidrógeno , Neurospora crassa/genéticaRESUMEN
The Neurospora crassa NIT-2 transcription factor belongs to the GATA transcription factor family and plays a fundamental role in the regulation of nitrogen metabolism. Because NIT-2 acts by accessing DNA inside the nucleus, understanding the nuclear import process of NIT-2 is necessary to characterize its function. Thus, in the present study, NIT-2 nuclear transport was investigated using a combination of biochemical, cellular, and biophysical methods. A complemented strain that produced an sfGFP-NIT-2 fusion protein was constructed, and nuclear localization assessments were made under conditions that favored protein translocation to the nucleus. Nuclear translocation was also investigated using HeLa cells, which showed that the putative NIT-2 nuclear localization sequence (NLS; 915TISSKRQRRHSKS927) was recognized by importin-α and that subsequent transport occurred via the classical import pathway. The interaction between the N. crassa importin-α (NcImpα) and the NIT-2 NLS was quantified with calorimetric assays, leading to the observation that the peptide bound to two sites with different affinities, which is typical of a monopartite NLS sequence. The crystal structure of the NcImpα/NIT-2 NLS complex was solved and revealed that the NIT-2 peptide binds to NcImpα with the major NLS-binding site playing a primary role. This result contrasts other recent studies that suggested a major role for the minor NLS-binding site in importin-α from the α2 family, indicating that both sites can be used for different cargo proteins according to specific metabolic requirements.
Asunto(s)
Transporte Activo de Núcleo Celular/fisiología , Proteínas de Unión al ADN/metabolismo , Proteínas Fúngicas/metabolismo , Neurospora crassa/metabolismo , Factores de Transcripción/metabolismo , alfa Carioferinas/metabolismo , Secuencia de Aminoácidos , Sitios de Unión/fisiología , Células Cultivadas , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Células HeLa , Humanos , Neurospora crassa/genética , Estructura Secundaria de Proteína , Esporas Fúngicas , Factores de Transcripción/química , Factores de Transcripción/genética , Difracción de Rayos X , alfa Carioferinas/química , alfa Carioferinas/genéticaRESUMEN
BACKGROUND: Glycogen and trehalose are storage carbohydrates and their levels in microorganisms vary according to environmental conditions. In Neurospora crassa, alkaline pH stress highly influences glycogen levels, and in Saccharomyces cerevisiae, the response to pH stress also involves the calcineurin signaling pathway mediated by the Crz1 transcription factor. Recently, in yeast, pH stress response genes were identified as targets of Crz1 including genes involved in glycogen and trehalose metabolism. In this work, we present evidence that in N. crassa the glycogen and trehalose metabolism is modulated by alkaline pH and calcium stresses. RESULTS: We demonstrated that the pH signaling pathway in N. crassa controls the accumulation of the reserve carbohydrates glycogen and trehalose via the PAC-3 transcription factor, which is the central regulator of the signaling pathway. The protein binds to the promoters of most of the genes encoding enzymes of glycogen and trehalose metabolism and regulates their expression. We also demonstrated that the reserve carbohydrate levels and gene expression are both modulated under calcium stress and that the response to calcium stress may involve the concerted action of PAC-3. Calcium activates growth of the Δpac-3 strain and influences its glycogen and trehalose accumulation. In addition, calcium stress differently regulates glycogen and trehalose metabolism in the mutant strain compared to the wild-type strain. While glycogen levels are decreased in both strains, the trehalose levels are significantly increased in the wild-type strain and not affected by calcium in the mutant strain when compared to mycelium not exposed to calcium. CONCLUSIONS: We previously reported the role of PAC-3 as a transcription factor involved in glycogen metabolism regulation by controlling the expression of the gsn gene, which encodes an enzyme of glycogen synthesis. In this work, we extended the investigation by studying in greater detail the effects of pH on the metabolism of the reserve carbohydrate glycogen and trehalose. We also demonstrated that calcium stress affects the reserve carbohydrate levels and the response to calcium stress may require PAC-3. Considering that the reserve carbohydrate metabolism may be subjected to different signaling pathways control, our data contribute to the understanding of the N. crassa responses under pH and calcium stresses.
Asunto(s)
Calcio/metabolismo , Glucógeno/metabolismo , Neurospora crassa/citología , Neurospora crassa/metabolismo , Transducción de Señal , Trehalosa/metabolismo , Regulación de la Expresión Génica de las Plantas , Concentración de Iones de Hidrógeno , Neurospora crassa/genética , Factores de Transcripción/metabolismoRESUMEN
Environmental pH induces a stress response triggering a signaling pathway whose components have been identified and characterized in several fungi. Neurospora crassa shares all six components of the Aspergillus nidulans pH signaling pathway, and we investigate here their regulation during an alkaline pH stress response. We show that the N. crassa pal mutant strains, with the exception of Δpal-9, which is the A. nidulans palI homolog, exhibit low conidiation and are unable to grow at alkaline pH. Moreover, they accumulate the pigment melanin, most likely via regulation of the tyrosinase gene by the pH signaling components. The PAC-3 transcription factor binds to the tyrosinase promoter and negatively regulates its gene expression. PAC-3 also binds to all pal gene promoters, regulating their expression at normal growth pH and/or alkaline pH, which indicates a feedback regulation of PAC-3 in the pal gene expression. In addition, PAC-3 binds to the pac-3 promoter only at alkaline pH, most likely influencing the pac-3 expression at this pH suggesting that the activation of PAC-3 in N. crassa results from proteolytic processing and gene expression regulation by the pH signaling components. In N. crassa, PAC-3 is proteolytically processed in a single cleavage step predominately at alkaline pH; however, low levels of the processed protein can be observed at normal growth pH. We also demonstrate that PAC-3 preferentially localizes in the nucleus at alkaline pH stress and that the translocation may require the N. crassa importin-α since the PAC-3 nuclear localization signal (NLS) has a strong in vitro affinity with importin-α. The data presented here show that the pH signaling pathway in N. crassa shares all the components with the A. nidulans and S. cerevisiae pathways; however, it exhibits some properties not previously described in either organism.
Asunto(s)
Concentración de Iones de Hidrógeno , Neurospora crassa/genética , Neurospora crassa/metabolismo , Transducción de Señal , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica , Prueba de Complementación Genética , Melaninas/biosíntesis , Monofenol Monooxigenasa , Mutación , Fenotipo , Regiones Promotoras Genéticas , Transporte de Proteínas , Proteolisis , alfa Carioferinas/metabolismoRESUMEN
When exposed to stress conditions, all cells induce mechanisms resulting in an attempt to adapt to stress that involve proteins which, once activated, trigger cell responses by modulating specific signaling pathways. In this work, using a combination of pulldown assays and mass spectrometry analyses, we identified the Neurospora crassa SEB-1 transcription factor that binds to the Stress Response Element (STRE) under heat stress. Orthologs of SEB-1 have been functionally characterized in a few filamentous fungi as being involved in stress responses; however, the molecular mechanisms mediated by this transcription factor may not be conserved. Here, we provide evidences for the involvement of N. crassa SEB-1 in multiple cellular processes, including response to heat, as well as osmotic and oxidative stress. The Δseb-1 strain displayed reduced growth under these conditions, and genes encoding stress-responsive proteins were differentially regulated in the Δseb-1 strain grown under the same conditions. In addition, the SEB-1-GFP protein translocated from the cytosol to the nucleus under heat, osmotic, and oxidative stress conditions. SEB-1 also regulates the metabolism of the reserve carbohydrates glycogen and trehalose under heat stress, suggesting an interconnection between metabolism control and this environmental condition. We demonstrated that SEB-1 binds in vivo to the promoters of genes encoding glycogen metabolism enzymes and regulates their expression. A genome-wide transcriptional profile of the Δseb-1 strain under heat stress was determined by RNA-seq, and a broad range of cellular processes was identified that suggests a role for SEB-1 as a protein interconnecting these mechanisms.
Asunto(s)
Sitios de Unión , Metabolismo de los Hidratos de Carbono , Neurospora crassa/genética , Neurospora crassa/metabolismo , Motivos de Nucleótidos , Elementos de Respuesta , Estrés Fisiológico , Factores de Transcripción/metabolismo , Secuencia de Aminoácidos , Inmunoprecipitación de Cromatina , Ambiente , Eliminación de Gen , Regulación Fúngica de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Fenotipo , Regiones Promotoras Genéticas , Unión Proteica , Estrés Fisiológico/genéticaRESUMEN
The transcription factor CreA/Mig1/CRE-1 is a repressor protein that regulates the use of alternative carbon sources via a mechanism known as Carbon Catabolite Repression (CCR). In Saccharomyces cerevisiae, Mig1 recruits the complex Ssn6-Tup1, the Neurospora crassa RCM-1 and RCO-1 orthologous proteins, respectively, to bind to promoters of glucose-repressible genes. We have been studying the regulation of glycogen metabolism in N. crassa and the identification of the RCO-1 corepressor as a regulator led us to investigate the regulatory role of CRE-1 in this process. Glycogen content is misregulated in the rco-1(KO), rcm-1(RIP) and cre-1(KO) strains, and the glycogen synthase phosphorylation is decreased in all strains, showing that CRE-1, RCO-1 and RCM-1 proteins are involved in glycogen accumulation and in the regulation of GSN activity by phosphorylation. We also confirmed the regulatory role of CRE-1 in CCR and its nuclear localization under repressing condition in N. crassa. The expression of all glycogenic genes is misregulated in the cre-1(KO) strain, suggesting that CRE-1 also controls glycogen metabolism by regulating gene expression. The existence of a high number of the Aspergillus nidulans CreA motif (5'-SYGGRG-3') in the glycogenic gene promoters led us to analyze the binding of CRE-1 to some DNA motifs both in vitro by DNA gel shift and in vivo by ChIP-qPCR analysis. CRE-1 bound in vivo to all motifs analyzed demonstrating that it down-regulates glycogen metabolism by controlling gene expression and GSN phosphorylation.