Project description:Renibacterium salmoninarum is a Gram-positive, intracellular bacterial pathogen that causes Bacterial Kidney Disease (BKD) in Atlantic salmon (Salmo salar). To identify R. salmoninarum bacterin-responsive genes in Atlantic salmon, fish (n=6) were intraperitoneally injected with a high (5×107 cells/kg; High-Rs) dose of formalin-killed R. salmoninarum or phosphate-buffered saline (PBS control). Head kidney samples were collected at 24 h post-injection. Using 44K microarray analysis, transcriptome analysis was performed to identify differentially expressed probes in response to formalin-killed R. salmoninarum injection.
Project description:Renibacterium salmoninarum is a Gram-positive, intracellular bacterial pathogen that causes Bacterial Kidney Disease (BKD) in Atlantic salmon (Salmo salar). To identify Atlantic salmon genes responsive to R. salmoninarum pathogen, fish were intraperitoneally injected with R. salmoninarum (BKD) or sterile KDM-2 medium (control). Head kidney samples were collected at 13 days post-infection. Using 44K microarray analysis, transcriptome analysis was performed to identify differentially expressed probes in response to different levels of R. salmoninarum infection.
Project description:Renibacterium salmoninarum, a slow-growing facultative intracellular pathogen belonging to the high C?+?G content Actinobacteria phylum, is the causative agent of bacterial kidney disease, a progressive granulomatous infection affecting salmonids worldwide. This Gram-positive bacterium has existed in the Chilean salmonid industry for >30?years, but little or no information is available regarding the virulence mechanisms and genomic characteristics of Chilean isolates. In this study, the genomes of two Chilean isolates (H-2 and DJ2R) were sequenced, and a search was conducted for genes and proteins involved in virulence and pathogenicity, and we compare with the type strain ATCC 33209?T genome. The genome sizes of H-2 and DJ2R are 3,155,332?bp and 3,155,228?bp, respectively. They genomes presented six ribosomal RNA, 46 transcription RNA, and 25 noncodingRNA, and both had the same 56.27% G?+?C content described for the type strain ATCC 33209?T. A total of 3,522 and 3,527 coding sequences were found for H-2 and DJ2R, respectively. Meanwhile, the ATCC 33209?T type strain had 3,519 coding sequences. The in silico genome analysis revealed a genes related to tricarboxylic acid cycle, glycolysis, iron transport and others metabolic pathway. Also, the data indicated that R salmoninarum may have a variety of possible virulence-factor and antibiotic-resistance strategies. Interestingly, many of genes had high identities with Mycobacterium species, a known pathogenic Actinobacteria bacterium. In summary, this study provides the first insights into and initial steps towards understanding the molecular basis of antibiotic resistance, virulence mechanisms and host/environment adaptation in two Chilean R. salmoninarum isolates that contain proteins of which were similar to those of Mycobacterium. Furthermore, important information is presented that could facilitate the development of preventive and treatment measures against R. salmoninarum in Chile and worldwide.
Project description:The myxozoan Tetracapsuloides bryosalmonae is the causative agent of proliferative kidney disease (PKD) – a disease of salmonid fishes, notably of the commercially farmed rainbow trout Oncorhynchus mykiss. Both wild and farmed salmonids are threatened by this virulent/deadly disease, which is often expressed by swollen kidneys. In order to understand the causes and consequences of the disease, we studied the immune response towards the parasite. To profile the influence of the disease on these cells, we produced a transcriptome of teleost RBCs in health and disease. Compared to erythrocytes originating from healthy fish, PKD fundamentally altered RBCs in their metabolism, adhesion, and response to inflammation.
Project description:Renibacterium salmoninarum is a genospecies that is an obligate pathogen of salmonid fish and is capable of intracellular survival. Conventional typing systems have failed to differentiate isolates of R. salmoninarum. We used two methods to assess the extent of molecular variation which was present in isolates from different geographic locations. In one analysis we investigated possible polymorphisms in a specific region of the genome, the intergenic spacer (ITS) region between the 16S and 23S rRNA genes. In the other analysis we analyzed differences throughout the genome by using randomly amplified polymorphic DNA (RAPD). We amplified the spacer region of 74 isolates by using PCR and performed a DNA sequence analysis with 14 geographically distinct samples. The results showed that the 16S-23S ribosomal DNA spacer region of R. salmoninarum is highly conserved and suggested that only a single copy of the rRNA operon is present in this slowly growing pathogen. DNA sequencing of the spacer region showed that it was the same length in all 14 isolates examined, and the same nucleotide sequence, sequevar 1, was obtained for 11 of these isolates. Two other sequevars were found. No tRNA genes were found. We found that RAPD analysis allows reproducible differentiation between isolates of R. salmoninarum obtained from different hosts and different geographic regions. By using RAPD analysis it was possible to differentiate between isolates with identical ITS sequences.