Unknown,Transcriptomics,Genomics,Proteomics

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Global modulation of gene expression in Paracoccidioides brasiliensis in response to thioridazine

ABSTRACT: Phenothiazines are antipsychotic drugs used in the treatment of schizophrenia, which have been shown to present antimicrobial activity (in vitro and in vivo) against a great variety of pathogenic microorganisms, including bacteria, parasites (protozoa and helmints) and fungi. In this study, we used competitive microarray hybridization to evaluate the effects of increasing concentrations of the piperidinic phenothiazine derivative thioridazine (TR) on the transcriptome of Paracoccidioides brasiliensis, the causative agent of paracoccidioidomycosis (PCM) - the most common systemic mycosis in Latin America. These analyses showed that the presence of TR affected expression of more than 1,800 genes from this fungus, including genes related to cellular processes such as cell wall metabolism and drug resistance. Microarray hybridizations were carried out with amplified RNA (aRNA), which was produced starting with total RNA extracted from cells treated with thioridazine (15, 20 or 25 M-BM-5M) for 168 hours. The aRNA synthesized from cells unexposed to TR was taken as reference. Each treatment was analyzed with two independent hybridizations (a pair of hybridizations, with dye-swaps within each pair). Since each biochip carried two replicas of the arrayed genes, a total of four intensity readings were generated for each element in the microarray.The data has been filtered, normalized and adjusted as described in the "data processing" box for each individual sample. Dye swap consistency checking has been performed between equivalent experimental pairs with the aid of the software TIGR MIDAS v2.19 and inconsistent spots have been flagged and excluded from further analyses. The values obtained from each dye swap pair have been averaged and consolidated into a single data file, generating a total of 8 hybridization files (four from each treatment concentration). These files have been loaded into the software TIGR Multi-Experiment Viewer, v.3.1 Experiments were then normalized and genes that displayed statistically significant modulation were identified by one-way ANOVA, considering p < 0.01 as a cutoff value. A list of statisticaly significant, modulated genes was created, showing the average log ratio for each one of these genes, within each time point.

ORGANISM(S): Paracoccidioides brasiliensis

SUBMITTER: Luiz Nunes

PROVIDER: E-GEOD-41881 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), the most common systemic mycosis in Latin America. The infection is initiated by inhalation of environmental dispersed conidia produced by the saprophytic phase of the fungus. In the lungs, P. brasiliensis assumes the parasitic yeast form and must cope with the adverse conditions imposed by cells of the host immune system, which includes a harsh environment highly concentrated in reactive oxygen species (ROS). In this work, we used the ROS-generating agent paraquat to experimentally simulate oxidative stress conditions in order to evaluate the stress-induced modulation in gene expression of cultured P. brasiliensis yeast cells using a microarray hybridization approach. Microarray hybridizations were carried out with RNA obtained from cells treated with paraquat (0.5 or 5.0 mM) for 5 hours. The RNA obtained from cells unexposed to paraquat was taken as reference. Each treatment was analyzed with four independent hybridizations (two pairs of dye-swapped hybridizations), using RNA from two biological replicas. The data has been filtered, normalized and adjusted as described in the "data processing" box for each individual sample. Dye swap consistency checking has been performed between equivalent experimental pairs with the aid of the software TIGR MIDAS v2.19 and inconsistent spots have been flagged and excluded from further analyses. The values obtained from each dye swap pair have been averaged and consolidated into a single data file, generating a total of 8 hybridization files (four from each treatment concentration). These files have been loaded into the software TIGR Multi-Experiment Viewer, v.3.01. Experiments were then normalized and genes that displayed statistically significant modulation were identified by one-way ANOVA, considering p < 0.01 as a cutoff value. A list of statisticaly significant, modulated genes was created, showing the average log ratio for each one of these genes, within each time point

Project description:BACKGROUND: Lithospermum erythrorhizon, popularly known as Gromwell, is a perennial herb belonging to the family of Boraginaceae and its extract is known to have diverse pharmacological, cosmetic, and nutritional values for human. Nevertheless the biological influence of Gromwell extract on general physiology of eukaryotic cells remains unknown. In this study, we for the first time performed a global transcriptome analysis by using DNA microarray analysis to identify genes affected by the addition of Gromwell extract (GE) by using a eukaryotic microorganism, basidiomycete fungus Cryptococcus neoformans, as a model system. RESULTS: The transcriptome analysis revealed that a total of 1932 genes are differentially regulated in a statistically significant manner and expressions of 715 genes are up- (315 genes) or down-regulated (457 genes) more than twofold upon GE treatment. In response to GE treatment, genes involved in signal transduction genes are immediately regulated and the evolutionarily conserved set of genes involved in the core cellular functions, including DNA replication, RNA transcription/processing, and protein translation/processing, are generally upregulated. In contrast, a number of genes involved in carbohydrate metabolism and transport, inorganic ion transport and metabolism, post-translational modification/protein turnover/chaperone functions, and signal transduction are downregulated by the GE treatment. Among the GE-responsive genes that are also evolutionarily conserved in the human genome, we confirmed expression patterns of YSA1, TPO2, FET5 (CFO1), and PZF1 by Northern blot analysis. Based on the functional characterization of some GE-responsive genes through phenotypic analysis of gene knockout mutants, we found that GE treatment may promote cellular tolerance against a variety of environmental stresses in eukaryotes. CONCLUSIONS: A significant portion of the Cryptococcus genome is affected in expression levels by treatment of GE, implying that the general physiology of eukaryotic cells is significantly affected by the GE treatment. There are more than 95% of genome homology between JEC21 and H99. Therefore 6 slides of JEC21 (Cryptococcus neoformans var. neoformans serotype D) 70-mer oligo are used in this analysis, 3 biological replicate experiments are performed, total RNAs are extracted from H99 (H99 Wild type strain (Cryptococcus neoformans var. grubii serotype A)) with 6.4 mg/ml Gromwell extract in 0, 10, 30, 60 min. We use the mixed all of total RNAs from this experiment as a control RNA. We use Cy3 as Sample dye and Cy5 as a control dye.

Project description:Analyzing culture supernatants of yeast and hyphal cells of Candida albicans by mass spectrometry, we found two close homologues of pathogenesis-related (PR-) 1 proteins, Rbe1p and Rbt4p, in the secretome of this human pathogen. By sequence homology, we assigned three yet not characterized open reading frames, ORF19.6200, ORF19.2787 and ORF19.2336, in addition to Rbe1p and Rbt4p to a novel family of proteins. Correspondent with our secretome analysis RBE1 was expressed in blastospores and opaque cells, whereas transcription was down-regulated in hyphae. On the contrary, RBT4 was up-regulated in hyphae and down-regulated in opaque cells. Remarkably, transcription of RBT4 and RBE1 was each up-regulated in blastospores of M-bM-^HM-^Frbe1 or hyphae of M-bM-^HM-^Frbt4 deletion strains, respectively, indicating a compensatory function of both proteins. In a M-bM-^HM-^Frbe1/M-bM-^HM-^Frbt4 double deletion strain, genome-wide transcriptional analysis showed differential transcription of a limited set of genes that are also implicated in virulence and oxidative stress response. In this context, deletion of RBE1 or RBT4 in a clinical C. albicans isolate resulted in a moderate but significant attenuation in virulence in a mouse model for disseminated candidiasis. However, a synergistic effect was observed in the M-bM-^HM-^Frbe1/M-bM-^HM-^Frbt4 double deletion strain, where virulence was strongly affected. Furthermore, the double deletion strain showed increased sensitivity to attack by polymorphonuclear leukocytes (neutrophils). Therfore, our data suggest that the crucial contribution of both C. albicans pathogenesis-related proteins for in vivo virulence results at least partially from reduced survival in phagocytes. Experiments were performed under blastospore (YPD) as well as hyphae (alpha-MEM)-inducing conditions. In total, three biological replicates were performed for each condition. All experiments were performed as dye swaps. Thus, in total six arrays have been hybridzed for each comparison (alpha-MEM and YPD, respectively). Hybridization experiments included a reference strain (C. albicans SC5314) and a double deletion strain (C. albicans MRC27). The array included one technical replicate of each probe.

Project description:Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is an important citrus disease that produces chlorotic injuries on leaves and reduced fruit size. This bacterium colonizes plant xylem, thereby interrupting sap flow. Other disease symptoms depend on environmental factors, since asymptomatic and symptomatic CVC plants may be genetically similar. The endophytic microbiome comprises many microbial species that may interact with pathogens, reducing disease symptoms and improving plant growth. However, the genetic and physiological mechanisms that underlie this interaction are largely unknown. In this study, the citrus endophytic bacterium Methylobacterium mesophilicum SR1.6/6 was isolated from healthy plants. This bacterium was able to colonize citrus xylem and could be transferred from plant to plant by Bucephalogonia xanthopis (Insecta), suggesting that this endophytic bacterium may interact with X. fastidiosa in planta, as a result of co-transmission by the same insect vector. To better understand how X. fastidiosa genetic responds to the presence of M. mesophilicum in the same environment, we used microarrays to evaluate the transcriptional profile of X. fastidiosa, after in vitro co-cultivation with M. mesophilicum SR1.6/6. The results showed that during co-cultivation with M. mesophilicum, X. fastidiosa downregulated genes related to growth, while genes related to energy production (cellular respiration) and transport were upregulated. Moreover, X. fastidiosa modulates genes associated with molecular recognition, nutrient competition and the stress response, suggesting the existence of a specific adaptive response to the presence of M. mesophilicum in the culture medium To evaluate and compare the Xylella fastidiosa 9a5c transcriptome profiles from bacteria cultured in PW and in co-cultive with Methylobacterium mesophilicum SR1.6/6, bacterial cultures were harvested for total RNA extraction after 24h of inoculation. Samples from the resulting RNAs were then used in competitive hybridizations against Xf microarrays. Replicated experiments were performed with RNA preparations from cells in each treatment and since each microarray carried two replicas of each spotted gene, we ended up with a series of 4 independent readings for each gene present in the microarrays. Images were analyzed with the TIGR Spotfinder program (v.2.2.4). All spots with median values lower than the median local background plus two Standard Deviations have been flagged and excluded from further analyses. Replicated experiments were performed with two independent RNA preparations from cells cultivated in each medium. For each pair of RNA preparations, two independent hybridizations were performed, with dye swaps within each pair. The results from each hybridization were submitted to a series of mathematical transformations with the aid of the software TIGR MIDAS v.2.19. These included filtering out all spots whose integrated intensities were below 10,000 a/d units, normalization between the two channels with the aid of the Lowess algorithm and SD regularization of the Cy5/Cy3 ratios across all sectors (blocks) of the array. Finally, the results from each individual experiment were loaded into the software TIGR Multi-Experiment Viewer (TMEV), v.3.01. Experiments were then normalized and genes that displayed statistically significant modulation were identified with the aid of the one-class option of the Significance Analysis of Microarrays (SAM) test, described by Tusher et al. (2001). The Î´ factor of the SAM test was adjusted to guarantee a False Discovery Rate (FDR) < 1.

Project description:The high osmolarity glycerol response (HOG) pathway plays a pivotal role in the stress response, virulence regulation, and differentiation of fungi, including Cryptococcus neoformans that causes fatal meningoencephalitis. Core signaling components of in the HOG pathway, including the Tco-Ypd1-Ssk1 phosphorelay system and the Ssk2-Pbs2-Hog1 MAPK module, have been elucidated but its downstream transcription factors remain unclear. Here we demonstrated that Atf1 with a basic leucine zipper domain is the transcription factor downstream of Hog1 in C. neoformans. We found that ATF1 expression was differentially regulated by oxidative damaging agents, mainly in a Hog1-dependent, but Mpk1-independent, manner. Interestingly, Atf1 not only promoted oxidative stress response and adaptation, but also played an opposing role to Hog1 in the process. Atf1 primarily localized to the nucleus under both unstressed and oxidative stress conditions in a Hog1-independent manner. Our data demonstrated that Atf1 promoted pheromone production and sexual differentiation under negative control by Hog1. Finally, a DNA microarray-based transcriptome analysis of the atf1M-bM-^HM-^F mutant under unstressed and oxidative stress conditions revealed that Atf1 regulated oxidative stress response genes, including a sulfiredoxin gene (SRX1). Intriguing, the array data further demonstrated that Atf1 modulated basal expression of genes involved in DNA repair and genotoxic stress response. Supporting this, we found that the atf1M-bM-^HM-^F mutant was highly sensitive to genotoxic agents. In conclusion, this study provided a further insight into the Hog1-dependent oxidative and genotoxic stress response and differentiation mechanism of C. neoformans. There are more than 95% of genome homology between JEC21 and H99. Therefore 6 slides of JEC21 (Cryptococcus neoformans var. neoformans serotype D) 70-mer oligo are used in this analysis, 3 biological replicate experiments are performed, total RNAs are extracted 2 conditions (with or without treatment of Hydroten peroxide) from H99 (H99 Wild type strain (Cryptococcus neoformans var. grubii serotype A), and atf1M-NM-^T). We use the mixed all of total RNAs from this experiment as a control RNA. We use Cy3 as Sample dye and Cy5 as a control dye.

Project description:Rice blast is the most threatening disease to cultivated rice worldwide. Magnaporthe oryzae, its causal agent is likely to encounter environmental challenges during invasive growth in the host plants that require shifts in gene expression to establish a compatible interaction. Here, we tested the hypothesis that M. oryzae have similar gene expression patterns in planta, versus during in vitro stresses. Gene expression data was collected from in vitro experiments of heat shock, oxidative burst, and three different types of nutrient starvation. These data were compared to fungal gene expression during the invasive growth phase in compatible interactions on two grass hosts, rice and barley. We have identified 4,973 differentially expressed genes, from which 1,909 genes showed similar regulation patterns between at least one of the in vitro stresses and rice and/or barley. Hierarchical clustering of these 1,909 genes showed three major clusters in which growth in planta conditions closely grouped with the starving nutrient conditions. Out of these 1,909 genes, 55 and 129 genes were induced and repressed in all seven treatments, respectively. The functional categorization of those 55 induced genes revealed that most of them are either related to carbon metabolism, membrane proteins, or are involved in oxidoreduction reactions. The 129 repressed genes are putatively involved in vesicle trafficking, signal transduction, nitrogen metabolism, or molecular transport. These findings indicated that M. oryzae is likely coping with nutrient deprived environments in its hosts during the invasive growth stage about 72 hours post-inoculation, and not as much with host defense responses, or a temperature stress. Eight M. oryzae treatments: mycelia grown in liquid complete medium (set as the control); 72 hours post-incoulation (hpi) in rice leaves; 72 hours post-incoulation in barley leaves; mycelia under heat shock; mycelia under oxidative stress; mycelia under minimal medium; mycelia under nitrogen starvation; mycelia under carbon starvation. Three biological replicates had their total RNA pulled after RNA extraction. Dye-swaps used as technical replicates.

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Global modulation of gene expression in Paracoccidioides brasiliensis in response to thioridazine

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