The unique Legionella longbeachae capsule favors intracellular replication and immune evasion
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ABSTRACT:
ORGANISM(S): Legionella longbeachae NSW150
PROVIDER: GSE272232 | GEO | 2024/10/15
REPOSITORIES: GEO
Similar Datasets
Project description:The unique Legionella longbeachae capsule favors intracellular replication and immune evasion
| PRJNA1135897 | ENA
Project description:Cryptococcus neoformans is a fungal pathogen with a polysaccharide capsule that becomes greatly enlarged in the mammalian host and during in vitro growth in response to host-like conditions. To understand how individual host-like signals affect capsule size and gene expression, we grew cells with and without all combinations of 5 signals suspected of affecting capsule size: Tissue-culture medium (DMEM or RPMI), temperature (37°C), CO2 (5%), and the addition of HEPES buffer. For each combination of conditions, we grew cultures with or without exogenous cAMP, and sampled cells for RNA-Seq at 0, 30, 90, 180, 1440 minutes and for measurement of capsule thickness at 1440 min. We also took samples for RNA-Seq at 30, 90, 180, 1440 minutes and carried out RNA-Seq in quadruplicate.
2023-08-02 | GSE226255 | GEO
Project description:Legionella pneumophila cells were harvested during exponential growth (RP) and stationary growth (TP). VBNC cells were also anylzed. Protein subfractions were studied.
2015-11-13 | PXD001926 | Pride
Project description:Cryptococcus neoformans is a fungal pathogen with a polysaccharide capsule that becomes greatly enlarged in the mammalian host and during in vitro growth in response to host-like conditions. To understand how individual host-like signals affect capsule size and gene expression, we grew cells wild-type KN99 cells with either no added cyclic AMP (cAMP), 1.1 mM, 1.8 mM, 3.3 mM, 11 mM, or 20 mM cAMP. capsule thickness at 1440 min. We also took samples for RNA-Seq at 30, 90, 180, 1440 minutes and carried out RNA-Seq in quadruplicate. We also measured capsule thickness at 1440 min.
2023-08-02 | GSE226637 | GEO
Project description:Cryptococcus neoformans is a fungal pathogen with a polysaccharide capsule that becomes greatly enlarged in the mammalian host and during in vitro growth in response to host-like conditions. To understand how individual host-like signals affect capsule size and gene expression, we grew wild-type cells and cells lacking components of the cAMP pathway: Pde1, Pde2, Pkr1. We also took samples for RNA-Seq at 30, 90, 180, 1440 minutes and carried out RNA-Seq in quadruplicate. We also measured capsule thickness at 1440 min.
2023-08-02 | GSE226651 | GEO
Project description:Cryptococcus neoformans causes meningoencephalitis and is an increasing human health threat. C. neoformans is neurotropic, and persists in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients such as carbon and nitrogen. To enhance our understanding of nutrient acquisition during infection by Cryptococcus species, we examined utilization of nitrogen sources available in CSF. We screened for growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Capsule production was assessed using ammonium and urea in the presence or absence of benomyl to determine the relationship of urea exposure to capsule production. Since urea is metabolized to ammonia and CO2 (a known signal for capsule induction), we examined urea metabolism mutants for their response to urea regarding capsule production. Non-preferred nitrogen sources were found to greatly affect capsule production in pathogenic species of Cryptococcus. Urea induced the greatest magnitude of capsule production. Capsule induction by urea was greater in Cryptococcus gattii strains than in C. neoformans strains. In addition, both environmental and clinical strains grew robustly on uric acid, casamino acids, creatinine, and asparagine as sole nitrogen sources. While substantial growth on nitrate was not apparent at day 3, growth was apparent by day 6 for all serotypes.
2013-09-25 | GSE46829 | GEO
Project description:Cryptococcus neoformans causes meningoencephalitis and is an increasing human health threat. C. neoformans is neurotropic, and persists in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients such as carbon and nitrogen. To enhance our understanding of nutrient acquisition during infection by Cryptococcus species, we examined utilization of nitrogen sources available in CSF. We screened for growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Capsule production was assessed using ammonium and urea in the presence or absence of benomyl to determine the relationship of urea exposure to capsule production. Since urea is metabolized to ammonia and CO2 (a known signal for capsule induction), we examined urea metabolism mutants for their response to urea regarding capsule production. Non-preferred nitrogen sources were found to greatly affect capsule production in pathogenic species of Cryptococcus. Urea induced the greatest magnitude of capsule production. Capsule induction by urea was greater in Cryptococcus gattii strains than in C. neoformans strains. In addition, both environmental and clinical strains grew robustly on uric acid, casamino acids, creatinine, and asparagine as sole nitrogen sources. While substantial growth on nitrate was not apparent at day 3, growth was apparent by day 6 for all serotypes. In this study, transcription profiles of urea pathway mutants (ure1 and amt1/2) and WT Cryptococcus neoformans strains were compared in a dye-swap experiment following 1hr exposure to proline or proline + urea (.25g/L).
2013-09-25 | E-GEOD-46829 | biostudies-arrayexpress
Project description:Legionella pneumophila is the causative agent of Legionnaires’ disease, an acute pulmonary infection. L. pneumophila is able to infect and multiply in both phagocytic protozoan, such as Acanthamoeba castellanii, and mammalian professional phagocytes. The best-known virulence determinant used by L. pneumophila to infect host cells is a Type IVb translocation system named Icm/Dot, which is used to modify the host cell functions to the benefit of the bacteria. To date the Icm/Dot systeme is known to translocate more than 100 effectors. While the transcriptional response of Legionella to the intracellular environement of A. castelannii as already been investigated, much less is known of how Legionella reacts transcriptionnally inside human macrophages. In this study, the transcriptome of L. pneumophila was monitored during exponential and post-exponential phase in rich AYE broth and during infection of human cultured macrophages by using microarray and a RNA amplification procedure called SCOTS to allow for the study of conditions of low bacterial loads. Among the genes induced intracellularly are those involved in amino acid synthesis pathway leading to L-arginine, L-histidne and L-proline as well as many transport system involved in amino acid and iron uptake. The Icm/Dot systems is not differentially expressed inside cells compare to the E phase control but the effectors are strongly induced. The intracellular transcriptome was further used to identify putative new Icm/Dot effectors and translocation was show to occur for 3 of them. This study provides a comprehensive view of how L. pneumophila react to the human macrophages intracellular environment.
2011-01-01 | GSE23029 | GEO
Project description:Cryptococcus neoformans is an opportunistic basidiomycete pathogen that is a major etiological agent of fungal meningoencephalitis leading to more than 180,000 deaths worldwide annually. For this pathogen, the polysaccharide capsule is a key virulence factor, which interferes with the phagocytosis by host innate immune cells, but its complex signaling networks remain elusive. In this study, we systematically analyzed capsule biosynthesis and signaling networks by using C. neoformans transcription factor (TF) and kinase mutant libraries under diverse capsule-inducing conditions, such as Dulbecco’s Modified Eagle’s (DME), Littman’s medium (LIT) and fetal bovine serum (FBS) medium. We found that deletion of GAT201, YAP1, BZP4, and ADA2 consistently causes capsule production defects in all tested media, indicating that they are capsule-regulating core TFs. Epistatic and expression analysis showed that Yap1 and Ada2 control Gat201 upstream, whereas Bzp4 and Gat201 regulate capsule production independently. We next searched for potential upstream kinases and found that mutants deleted of PKA1, BUD32, POS5, IRE1 or CDC2801 showed reduced capsule production under all three capsule induction conditions, whereas mutants deleted of HOG1 and IRK5 displayed enhanced capsule production. Notably, Pka1 and Irk5 controls induction of GAT201 and BZP4, respectively, under capsule induction condition. Finally, we monitored transcriptome profiles governed by Bzp4, Gat201, and Ada2 under capsule-inducing condition and demonstrated that these TFs regulate redundant and unique sets of downstream target genes. In conclusion, this study provides further insight into the complex regulatory mechanism of capsule production related signaling pathways in C. neoformans.
2022-10-18 | GSE208163 | GEO
Project description:The intracellular pathogen Legionella pneumophila (Lp) is a strict aerobe, surviving and replicating in environments where it frequently encounters reactive oxygen species, such as the nutrient-poor water environment and inside host cells. In many proteobacteria, the oxidative stress response is regulated by the LysR-type regulator OxyR; however, the role played by the OxyR homologue in Lp is still unclear. Therefore, we undertook the characterisation of the phenotypes associated with the deletion of OxyR in Lp. OxyR is dispensable for growth in rich broth, in amoeba and in human cultured macrophages, and for the survival of Lp in water. Nevertheless, the mutant was found to be more sensitive to hydrogen peroxide than the wild-type when grown to post-exponential phase, but not when grown to exponential phase. Moreover, the mutant is defective in forming isolated colonies on charcoal yeast extract (CYE) agar plates, but supplementation with anti-ROS molecules, such as pyruvate, α-ketoglutarate and catalase, rescued this defect. Further characterisation of this phenotype using a transcriptional reporter fusion and microarray analysis revealed that the deletion mutant is not defective for the expression of known anti-ROS genes which suggests that the growth defect on agar plates and the higher susceptibility to hydrogen peroxide are due to a broad change in the transcriptional response. Furthermore, the growth defect is suppressed when the mutant is grown on CYE plates made with agarose, suggesting that a compound present in typical agar is toxic for the oxyR mutant.
2021-07-20 | GSE87029 | GEO