Browsing by Author "Duarte, Daniel F. C."
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- Transcriptome analysis of Immune Response against Streptococcus agalactiae infection in the Nile Tilapia GIFT StrainPublication . Zhou, Tao; Fang, Zhihua; Duarte, Daniel F. C.; Fernandes, Stefan A.; Lu, Ying; Guo, Jing; Gui, Lang; Chen, LiangbiaoStreptococcus agalactiae (group B streptococcus, GBS), a broad-spectrum pathogen, causes great economic losses in fish aquaculture, especially the industry of tilapia. Until now, the knowledge of the immune response mechanism against S. agalactiae infection in tilapia has been limited. In the present study, the gill transcriptome of the tilapia from the GBS and the phosphate buffered saline (PBS) groups were sequenced. The transcriptomic analysis results presented the differentially expressed genes (DEGs) at different time points (DEGs number, 6 h: 2122, 9 h: 1851, 15 h: 1791, and 18 h: 2395) after GBS injection, and significantly enriched immune-related gene ontology (GO) terms such as the innate immune response. The significantly enriched immune pathways included the Toll-like receptor signaling pathway, the nucleotide oligomerization domain (NOD)-like receptor signaling pathway, the cytosolic-DNA sensing pathway, and the intestinal immune network for Immunoglobulin A (IgA) production. Most of the DEGs in Toll-like receptor signaling, NOD-like receptor signaling, and cytosolic-DNA sensing pathways presented upregulations at 18 h, which indicated that the innate immune pathways were activated. Two immune-related pathways (phagosome and cell adhesion molecules) were significantly enriched at all time points, suggesting that these two pathways might also play important roles in the immune response against the GBS infection. The results of HE staining showed that the gills of tilapia were damaged seriously at 9 h post-infection, which might be due to the possibility of pyroptosis resulting from the changes of DEGs in the NODlike receptor signaling pathway. This study provided new insight into the mechanisms of gill damage in fish infected with S. agalactiae.
- Transcriptomic responses to low temperature stress in the Nile tilapia, Oreochromis niloticusPublication . Zhou, Tao; Gui, Lang; Liu, Mingli; Li, Wenhao; Hu, Peng; Duarte, Daniel F. C.; Niu, Hongbo; Chen, LiangbiaoThe Nile tilapia, Oreochrornis niloticus, is a species of high economic value and extensively cultured. The limited stress tolerance of this species to a low temperature usually leads to mass mortality and great loss. Nevertheless, there is limited information on the molecular mechanisms underlying the susceptibility to low temperature in the tilapia. In this study, tilapia was treated at 28 degrees C to a lethal temperature of 8 degrees C by a gradual decrement. Transcriptomic response of the immune organ, kidney, in tilapia was characterized using RNA-seq. In total, 2191 genes were annotated for significant expression, which were mainly associated with metabolism and immunity. Pathway analysis showed that immune-related pathways of phagosome and cell adhesion molecules (CAMs) pathway were significantly down-regulated under low temperature. Moreover, ferroptosis, a significantly changed pathway involved in tissue damage and acute renal failure, is reported here for the first time. The levels of serum parameters associated with kidney damage such as urea and uric acid (UA) increased significantly under low temperature. The immunofluorescence staining of the kidney showed that cell apoptosis occurred at low temperature. The results of the present study indicate that exposure to low temperature can cause kidney disfunction and down-regulate the immune-related pathway in the kidney of tilapia. This study provides new insight into the mechanism of kidney damage in fish under low temperature.