Expression of flagellin and key regulatory flagellar genes in the non-motile bacterium Piscirickettsia salmonis

2017 ◽  
Vol 123 (1) ◽  
pp. 29-43 ◽  
Author(s):  
GP Carril ◽  
FA Gómez ◽  
SH Marshall
Keyword(s):  
Piscirickettsia Salmonis ◽  
Motile Bacterium ◽  
Flagellar Genes

scholarly journals The Analysis of Live-Attenuated Piscirickettsia salmonis Vaccine Reveals the Short-Term Upregulation of Innate and Adaptive Immune Genes in Atlantic Salmon (Salmo salar): An In Situ Open-Sea Cages Study

2021 ◽  
Vol 9 (4) ◽  
pp. 703
Author(s):  
Deborah Vargas ◽  
Eva Vallejos-Vidal ◽  
Sebastián Reyes-Cerpa ◽  
Aarón Oyarzún-Arrau ◽  
Claudio Acuña-Castillo ◽  
...  
Keyword(s):  
Immune Response ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Cellular Response ◽  
Short Term ◽  
Live Attenuated Vaccine ◽  
Gene Markers ◽  
Post Vaccination ◽  
Atlantic Salmon Salmo Salar ◽  
Piscirickettsia Salmonis

Piscirickettsia salmonis, the etiological agent of the Salmon Rickettsial Septicemia (SRS), is one the most serious health problems for the Chilean salmon industry. Typical antimicrobial strategies used against P. salmonis include antibiotics and vaccines, but these applications have largely failed. A few years ago, the first attenuated-live vaccine against SRS (ALPHA JECT LiVac® SRS vaccine) was released to the market. However, there is no data about the agents involved in the activation of the immune response induced under field conditions. Therefore, in this study we evaluated the expression profile of a set of gene markers related to innate and adaptive immunity in the context of a cellular response in Atlantic salmon (Salmo salar) reared under productive farm conditions and immunized with a live-attenuated vaccine against P. salmonis. We analyzed the expression at zero, 5-, 15- and 45-days post-vaccination (dpv). Our results reveal that the administration of the attenuated live SRS LiVac vaccine induces a short-term upregulation of the cellular-mediated immune response at 5 dpv modulated by the upregulation of ifnα, ifnγ, and the cd4 and cd8α T cell surface markers. In addition, we also registered the upregulation of il-10 and tgfβ. Altogether, the results suggest that a balanced activation of the immune response took place only at early times post-vaccination (5 dpv). The scope of this short-term upregulation of the cellular-mediated immune response against a natural outbreak in fish subjected to productive farm conditions deserves further research.

scholarly journals “Limiting access to iron decreases infection of Atlantic salmon SHK-1 cells with bacterium Piscirickettsia salmonis”

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Rodrigo Díaz ◽  
José Troncoso ◽  
Eva Jakob ◽  
Stanko Skugor
Keyword(s):  
Gene Expression ◽  
Iron Deficiency ◽  
Atlantic Salmon ◽  
Bacterial Load ◽  
Host Cells ◽  
Immune Gene ◽  
Immune Signaling ◽  
Immune Effector ◽  
Infected Cells ◽  
Piscirickettsia Salmonis

Abstract Background Vertebrate hosts limit the availability of iron to microbial pathogens in order to nutritionally starve the invaders. The impact of iron deficiency induced by the iron chelator deferoxamine mesylate (DFO) was investigated in Atlantic salmon SHK-1 cells infected with the facultative intracellular bacterium Piscirickettsia salmonis. Results Effects of the DFO treatment and P. salmonis on SHK-1 cells were gaged by assessing cytopathic effects, bacterial load and activity, and gene expression profiles of eight immune biomarkers at 4- and 7-days post infection (dpi) in the control group, groups receiving single treatments (DFO or P. salmonis) and their combination. The chelator appears to be well-tolerated by host cells, while it had a negative impact on the number of bacterial cells and associated cytotoxicity. DFO alone had minor effects on gene expression of SHK-1 cells, including an early activation of IL-1β at 4 dpi. In contrast to few moderate changes induced by single treatments (either infection or chelator), most genes had highest upregulation in the infected groups receiving DFO. The mildest induction of hepcidin-1 (antimicrobial peptide precursor and regulator of iron homeostasis) was observed in cells exposed to DFO alone, followed by P. salmonis infected cells while the addition of DFO to infected cells further increased the mRNA abundance of this gene. Transcripts encoding TNF-α (immune signaling) and iNOS (immune effector) showed sustained increase at both time points in this group while cathelicidin-1 (immune effector) and IL-8 (immune signaling) were upregulated at 7 dpi. The stimulation of protective gene responses seen in infected cultures supplemented with DFO coincided with the reduction of bacterial load and activity (judged by the expression of P. salmonis 16S rRNA), and damage to cultured host cells. Conclusion The absence of immune gene activation under normal iron conditions suggests modulation of host responses by P. salmonis. The negative effect of iron deficiency on bacteria likely allowed host cells to respond in a more protective manner to the infection, further decreasing its progression. Presented findings encourage in vivo exploration of iron chelators as a promising strategy against piscirickettsiosis.

scholarly journals Optimization of florfenicol dose against Piscirickettsia salmonis in Salmo salar through PK/PD studies

PLoS ONE ◽  
2019 ◽  
Vol 14 (5) ◽  
pp. e0215174 ◽  
Author(s):  
Betty San Martín ◽  
Marcela Fresno ◽  
Javiera Cornejo ◽  
Marcos Godoy ◽  
Rolando Ibarra ◽  
...  
Keyword(s):  
Salmo Salar ◽  
Piscirickettsia Salmonis

scholarly journals Role of the Helicobacter hepaticus Flagellar Sigma Factor FliA in Gene Regulation and Murine Colonization

2008 ◽  
Vol 190 (19) ◽  
pp. 6398-6408 ◽  
Author(s):  
Torsten Sterzenbach ◽  
Lucie Bartonickova ◽  
Wiebke Behrens ◽  
Birgit Brenneke ◽  
Jessika Schulze ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Sigma Factor ◽  
Intestinal Inflammation ◽  
Gall Stone ◽  
Helicobacter Hepaticus ◽  
Intestinal Colonization ◽  
Wild Type ◽  
Chronic Intestinal Inflammation ◽  
Flagellar Genes

ABSTRACT The enterohepatic Helicobacter species Helicobacter hepaticus colonizes the murine intestinal and hepatobiliary tract and is associated with chronic intestinal inflammation, gall stone formation, hepatitis, and hepatocellular carcinoma. Thus far, the role of H. hepaticus motility and flagella in intestinal colonization is unknown. In other, closely related bacteria, late flagellar genes are mainly regulated by the sigma factor FliA (σ28). We investigated the function of the H. hepaticus FliA in gene regulation, flagellar biosynthesis, motility, and murine colonization. Competitive microarray analysis of the wild type versus an isogenic fliA mutant revealed that 11 genes were significantly more highly expressed in wild-type bacteria and 2 genes were significantly more highly expressed in the fliA mutant. Most of these were flagellar genes, but four novel FliA-regulated genes of unknown function were identified. H. hepaticus possesses two identical copies of the gene encoding the FliA-dependent major flagellin subunit FlaA (open reading frames HH1364 and HH1653). We characterized the phenotypes of mutants in which fliA or one or both copies of the flaA gene were knocked out. flaA_1 flaA_2 double mutants and fliA mutants did not synthesize detectable amounts of FlaA and possessed severely truncated flagella. Also, both mutants were nonmotile and unable to colonize mice. Mutants with either flaA gene knocked out produced flagella morphologically similar to those of wild-type bacteria and expressed FlaA and FlaB. flaA_1 mutants which had flagella but displayed reduced motility did not colonize mice, indicating that motility is required for intestinal colonization by H. hepaticus and that the presence of flagella alone is not sufficient.

scholarly journals Basal Body Structures Differentially Affect Transcription of RpoN- and FliA-Dependent Flagellar Genes in Helicobacter pylori

2015 ◽  
Vol 197 (11) ◽  
pp. 1921-1930 ◽  
Author(s):  
Jennifer Tsang ◽  
Timothy R. Hoover
Keyword(s):  
Helicobacter Pylori ◽  
Basal Body ◽  
Protein Interactions ◽  
Transcript Levels ◽  
Content Type ◽  
Genes Encoding ◽  
H Pylori ◽  
Flagellar Biogenesis ◽  
Flagellar Genes

ABSTRACTFlagellar biogenesis inHelicobacter pyloriis regulated by a transcriptional hierarchy governed by three sigma factors, RpoD (σ80), RpoN (σ54), and FliA (σ28), that temporally coordinates gene expression with the assembly of the flagellum. Previous studies showed that loss of flagellar protein export apparatus components inhibits transcription of flagellar genes. The FlgS/FlgR two-component system activates transcription of RpoN-dependent genes though an unknown mechanism. To understand better the extent to which flagellar gene regulation is coupled to flagellar assembly, we disrupted flagellar biogenesis at various points and determined how these mutations affected transcription of RpoN-dependent (flaBandflgE) and FliA-dependent (flaA) genes. The MS ring (encoded byfliF) is one of the earliest flagellar structures assembled. Deletion offliFresulted in the elimination of RpoN-dependent transcripts and an ∼4-fold decrease inflaAtranscript levels. FliH is a cytoplasmic protein that functions with the C ring protein FliN to shuttle substrates to the export apparatus. Deletions offliHand genes encoding C ring components (fliMandfliY) decreased transcript levels offlaBandflgEbut had little or no effect on transcript levels offlaA. Transcript levels offlaBandflgEwere elevated in mutants where genes encoding rod proteins (fliEandflgBC) were deleted, while transcript levels offlaAwas reduced ∼2-fold in both mutants. We propose that FlgS responds to an assembly checkpoint associated with the export apparatus and that FliH and one or more C ring component assist FlgS in engaging this flagellar structure.IMPORTANCEThe mechanisms used by bacteria to couple transcription of flagellar genes with assembly of the flagellum are poorly understood. The results from this study identified components of theH. pyloriflagellar basal body that either positively or negatively affect expression of RpoN-dependent flagellar genes. Some of these basal body proteins may interact directly with regulatory proteins that control transcription of theH. pyloriRpoN regulon, a hypothesis that can be tested by examining protein-protein interactionsin vitro.

scholarly journals Core non-coding RNAs of Piscirickettsia salmonis

PLoS ONE ◽  
2018 ◽  
Vol 13 (5) ◽  
pp. e0197206 ◽  
Author(s):  
Cristopher Segovia ◽  
Raul Arias-Carrasco ◽  
Alejandro J. Yañez ◽  
Vinicius Maracaja-Coutinho ◽  
Javier Santander
Keyword(s):  
Non Coding Rnas ◽  
Piscirickettsia Salmonis

scholarly journals Diatom flagellar genes and their expression during sexual reproduction in Leptocylindrus danicus

BMC Genomics ◽  
2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Deepak Nanjappa ◽  
Remo Sanges ◽  
Maria I. Ferrante ◽  
Adriana Zingone
Keyword(s):  
Sexual Reproduction ◽  
Flagellar Genes
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