Browsing by Author "Yuanlae S."

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    Ecytonucleospora hepatopenaei causes lipid droplet depletion and imbalanced lipid metabolism in Penaeus vannamei
    (2025-12-01) Yuanlae S.; Thaiue D.; Saedan S.; Kittiwongpukdee K.; Vanichviriyakit R.; Chuchird N.; Itsathitphaisarn O.; Yuanlae S.; Mahidol University
    Ecytonucleospora hepatopenaei (EHP) infection in Penaeus vannamei causes significant economic losses in shrimp aquaculture due to growth retardation. Unable to generate ATP, EHP obligately relies on host energy production to survive. We hypothesize that EHP may potentially disrupt its host’s lipid metabolism as lipid is the most energy-dense resource. To this end, the effects of EHP infection on lipid metabolism were investigated by evaluating activities and expressions of digestive enzymes, accumulation of lipid droplets, and expression of genes involved in lipid breakdown and synthesis. Results revealed that EHP infection progressively diminished digestive enzyme activities, leading to reduced nutrient availability. A persistent reduction of lipid droplet accumulation was detected from the onset of EHP infection. The marked decrease in the early stages was attributable to increased lipid droplet breakdown outpacing lipid synthesis. In the later stage, a partial recovery of lipid synthesis gene expression was observed; however, this was insufficient to counteract increased lipid breakdown, as genes in this pathway were upregulated. Ultimately, this imbalance resulted in a marked depletion of lipid droplets. These findings highlight how EHP infection chronically impairs digestion, drains lipid reservoir of its host and, eventually, retards growth. In terms of a potential practical solution, this study implies that dietary lipid supplementation might alleviate the metabolic disruption of EHP and, thereby, lessen the extent of growth retardation in infected population.
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    Shrimp injection with dsRNA targeting the microsporidian EHP polar tube protein reduces internal and external parasite amplification
    (2024-12-01) Yuanlae S.; Prasartset T.; Reamtong O.; Munkongwongsiri N.; Panphloi M.; Preechakul T.; Suebsing R.; Thitamadee S.; Prachumwat A.; Itsathitphaisarn O.; Taengchaiyaphum S.; Kasamechotchung C.; Yuanlae S.; Mahidol University
    The microsporidian Enterocytozoon hepatopenaei (EHP) is a major threat to shrimp health worldwide. Severe EHP infections in shrimp cause growth retardation and increase susceptibility to opportunistic infections. EHP produces spores with a chitin wall that enables them to survive prolonged environmental exposure. Previous studies showed that polar tube extrusion is a prerequisite for EHP infection, such that inhibiting extrusion should prevent infection. Using a proteomic approach, polar tube protein 2 of EHP (EhPTP2) was found abundantly in protein extracts obtained from extruded spores. Using an immunofluorescent antibody against EhPTP2 for immunohistochemistry, extruded spores were found in the shrimp hepatopancreas (HP) and intestine, but not in the stomach. We hypothesized that presence of EhPTP2 might be required for successful EHP spore extrusion. To test this hypothesis, we injected EhPTP2-specific double-stranded RNA (dsRNA) and found that it significantly diminished EHP copy numbers in infected shrimp. This indicated reduced amplification of EHP-infected cells in the HP by spores released from previously infected cells. In addition, injection of the dsRNA into EHP-infected shrimp prior to their use in cohabitation with naïve shrimp significantly (p < 0.05) reduced the rate of EHP transmission to naïve shrimp. The results revealed that EhPTP2 plays a crucial role in the life cycle of EHP and that dsRNA targeting EHP mRNA can effectively reach the parasite developing in host cells. This approach is a model for future investigations to identify critical genes for EHP survival and spread as potential targets for preventative and therapeutic measures in shrimp.