ABSTRACT: Prediction, microarray and Northern blot analyses identify new intergenic small RNAs in Aliivibrio salmonicida (LB medium vs. iron-limited condition)
Project description:This SuperSeries is composed of the following subset Series: GSE25545: Prediction, microarray and Northern blot analyses identify new intergenic small RNAs in Aliivibrio salmonicida (LB medium vs. iron-limited condition) GSE25546: Prediction, microarray and Northern blot analyses identify new intergenic small RNAs in Aliivibrio salmonicida (wild type vs. LitR mutant) Refer to individual Series
Project description:Prediction, microarray and Northern blot analyses identify new intergenic small RNAs in Aliivibrio salmonicida (wild type vs. LitR mutant)
Project description:Expression profiling of a spf deletion mutant suggests biological roles and mRNA targets for Spot 42 in the fish pathogen Aliivibrio salmonicida
Project description:Aliivibrio (Vibrio) salmonicida is the causative agent of cold-water vibriosis in salmonids (Oncorhynchus mykiss and Salmo salar L.) and gadidae (Gadus morhua L.). Virulence-associated factors that are essential for the full spectrum of Al. salmonicida pathogenicity are largely unknown. Chitin-active lytic polysaccharide monooxygenases (LPMOs) have been indicated to play roles in both chitin degradation and virulence in a variety of pathogenic bacteria. In the present study we investigated the role of LPMOs in the pathogenicity of Al. salmonicida LFI238 in Atlantic salmon (Salmo salar L.). In vivo challenge experiments using isogenic deletion mutants of the two LPMOs encoding genes AsLPMO10A and AsLPMO10B, showed that both LPMOs, and in particular AsLPMO10B, were important in the invasive phase of cold-water vibriosis. Crystallographic analysis of the AsLPMO10B AA10 LPMO domain (to 1.4 Å resolution) revealed high structural similarity to viral fusolin, an LPMO known to enhance the virulence of insecticidal agents. Finally, exposure to Atlantic salmon serum resulted in substantial proteome re-organization of the Al. salmonicida LPMO deletion variants compared to the wild type strain, indicating the struggle of the bacterium to adapt to the host immune components.
Project description:Iron is an essential micronutrient for all living organisms, and sequestering of iron and the virulence of pathogenic bacteria are believed to be correlated. As the defense mechanisms, potential hosts therefore keep the level of free iron inside the body to a minimum. The iron metabolism is well studied in general for several pathogens of humans and animals, but it is still mostly unclear how gene expression levels change in pathogens during the initial stages of infections. In this work, using Aliivibrio salmonicida we studied the immediate changes in transcription levels in response to a sudden decrease in iron levels. Microarray technology was used to monitor global changes in transcriptional levels. Cultures of A. salmonicida were grown to mid log phase before the iron chelator 2,2M-bM-^@M-^Y-dipyridyl was added and samples were collected after 15 minutes of growth. Using our statistical cut-off values, we retrieved thirty-two differentially expressed genes where the most up-regulated genes belong to an operon encoding proteins responsible for producing the siderophore bisucaberin. Six biological replicates of A. salmonicida wild type strain LFI1238 were grown in suspension in LB medium, at 8 M-BM-0C , 200 rpm and split in two halves at OD600nm 0.5, keeping one half of each replicate as control (still growing while the treated samples were growing with 2,2-dipyridyl treatment) while the other half were treated with 50M-BM-5M 2,2-dipyridyl for 15 minutes.
