Project description:World aquaculture production of the Pacific white shrimp (Litopenaeus vannamei) is estimated to account for 80% of the total shrimp produce worldwide. The global demand for shrimp has driven the industry to utilize and rely on semi-intensive and intensive shrimp systems. In the United States, Pacific white shrimp production can take place in semi-intensive earthen ponds, recirculating aquaculture systems (RAS), biofloc technology and green water. In this study, the effects of lowering dissolved oxygen conditions in outdoor green water tanks on global gene expression is examined. Tissue samples from the gill and intestine were collected for gene expression analysis via RNA sequencing. Among all comparisons, RNA sequencing revealed the up-regulation of a single gene: hydroxyacid oxidase 1 gene. The HOA1 gene was found to be 7-fold higher in the intestine sample at the medium aeration level compare to that of the high (control) level. The HAO1 gene, also known as glycolate oxidase 1 (GOX1) is a gene related to the 2-hydroxyacid oxidase enzyme that is part of the oxidoreductase family and plays a role in glyoxylate and dicarboxylate metabolism. The identification of a single differentially expressed gene across all analyzed samples suggests that Pacific white shrimp exposed to lowering dissolved oxygen set points does not induce global changes in gene expression at these levels.
Project description:With the global increase in the use of carbapenems, several gram-negative bacteria have acquired carbapenem resistance, thereby limiting treatment options. Klebsiella pneumoniae is one of such notorious pathogen that is being widely studied to find novel resistance mechanisms and drug targets. These antibiotic-resistant clinical isolates generally harbor many genetic alterations, and identification of causal mutations will provide insights into the molecular mechanisms of antibiotic resistance. We propose a method to prioritize mutated genes responsible for antibiotic resistance, in which mutated genes that also show significant expression changes among their functionally coupled genes become more likely candidates. For network-based analyses, we developed a genome-scale co-functional network of K. pneumoniae genes, KlebNet (www.inetbio.org/klebnet). Using KlebNet, we could reconstruct functional modules for antibiotic-resistance, and virulence, and retrieved functional association between them. With complementation assays with top candidate genes, we could validate a gene for negative regulation of meropenem resistance and four genes for positive regulation of virulence in Galleria mellonella larvae. Therefore, our study demonstrated the feasibility of network-based identification of genes required for antimicrobial resistance and virulence of human pathogenic bacteria with genomic and transcriptomic profiles from antibiotic-resistant clinical isolates.
Project description:The phenomenon of trained immunity, which facilitates vaccine development for disease control, has been identified in shrimp; however, the mechanism remains elusive. In the present study, we found that histone H3K27 acetylation (H3K27ac) mediated by the lysine acetyltransferase KAT8 plays an important role in preventing white spot syndrome virus (WSSV) infection in the shrimp Marsupenaeus japonicus. We then successfully established a model of trained immunity via the use of UV-inactivated WSSV to explore the underlying mechanism(s) in shrimp. In UV-WSSV-trained shrimp, the glycolysis and tricarboxylic acid (TCA) cycle metabolic pathways were enhanced and acetyl-CoA concentrations were increased. As the acetyl group donor, acetyl-CoA promotes KAT8 activity to increase H3K27 acetylation. H3K27ac is deposited at the promoter region of the transcription factor Dorsal to facilitate its expression and then Dorsal promotes the expression of an interferon-like cytokine, Vago5, and antimicrobial peptides that act against WSSV infection. H3K27ac is also deposited at the promoter region of hexokinase 2 and isocitrate dehydrogenase, which positively regulates glycolysis and the TCA cycle in a feedforward manner. Our results reveal a novel mechanism of trained immunity induced by UV-WSSV in shrimp and provide a theoretical basis for the development of antiviral vaccines for disease control in shrimp aquaculture.
Project description:Acute hepatopancreatic necrosis disease (AHPND) is a shrimp farming disease, caused by a pathogenic Vibrio parahaemolyticus carrying a plasmid encoding Vp_PirAB-like toxin (VpAHPND). Whiteleg shrimp, Litopenaeus vannamei were fed food pellets containing formalin-killed VpAHPND (FKC-VpAHPND) to select for toxin resistance. To identify genes associated with Vp_PirAB-like toxin resistance, total RNA was sequenced to identify differentially expressed genes (DEGs) in the stomach and hepatopancreas among surviving shrimp (sur-FKC), AHPND-infected shrimp (Vp-inf) and normal shrimp (control). From a total of 79,591 genes, 194 and 224 DEGs were identified in the stomach and hepatopancreas transcriptomes, respectfully. The expressions of DEGs were validated by qPCR of ten genes. Only one gene, a gene homologous to L vannamei anti-lipopolysaccharide factor AV-R isoform (LvALF AV-R), was expressed significantly more strongly in sur-FKC than in the other groups. The association of LvALF AV-R expression and toxin resistance was affirmed from the surviving shrimp in a second-trial of FKC-VpAHPND feeding. These results suggest that LvALF AV-R may be involved in shrimp defense mechanisms against Vp_PirAB-like toxin virulence.