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Published on: February 22, 2019
Immune responses and gene expression in hepatopancreas from Macrobrachium rosenbergii challenged by a novel pathogen
1Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
Abstract:
Freshwater prawn Macrobrachium rosenbergii inoculated with 100 μl novel pathogen spiroplasma strain MR-1008 in logarithmic phase (10(8) spiroplasmas ml(-1)) were examined for alkaline phosphatase (AKP) activity, acid phosphatase (ACP) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity, as well as expressions of 7 immune related genes in hepatopancreas after 1-28 d. Hematoxylin-eosin (HE) staining showed obvious pathological features in hepatopancreas connective and epithelial tissue. Enzyme activity analyze showed that hepatopancreas AKP and ACP activity increased markedly (P < 0.05) when inoculated with spiroplasma MR-1008 after 5 d and 10 d, respectively. SOD enzyme activity changed less obviously and slightly increased at 1 day post-inoculation, but CAT activity decreased significantly after 5 d inoculation. The expression levels of lipopolysaccharide and β-1,3-glucan-binding protein (LGBP), peroxinectin (PE), α2-macroglobulin (α2M), AKP, ACP, CAT, and copper/zinc SOD (Cu, Zn-SOD) genes in the hepatopancreas were examined by Real-Time PCR (qRT-PCR) and the results demonstrated that these immune related genes were induced by challenge with spiroplasma MR-1008. The results suggested that the prawn immune responses could be activated or inhibited by spiroplasma MR-1008, and that the hepatopancreas also plays key roles in innate immunity for defense against the pathogen.
Insights
This study investigated the effects of Spiroplasma MR-1008 on the freshwater prawn Macrobrachium rosenbergii. The pathogen altered immune enzyme activities and gene expression in the hepatopancreas, indicating a complex immune response.
Area of Science:
- Aquaculture immunology
- Invertebrate pathology
- Molecular biology
Background:
- The freshwater prawn Macrobrachium rosenbergii is susceptible to various pathogens.
- Spiroplasma infections can cause significant losses in aquaculture.
- Understanding the prawn's immune response to Spiroplasma is crucial for disease management.
Purpose of the Study:
- To investigate the impact of Spiroplasma MR-1008 on the immune system of Macrobrachium rosenbergii.
- To analyze changes in immune enzyme activities and gene expression in response to Spiroplasma infection.
- To elucidate the role of the hepatopancreas in the prawn's innate immunity against Spiroplasma.
Main Methods:
- Macrobrachium rosenbergii were challenged with Spiroplasma MR-1008.
- Hematoxylin-eosin staining was used to examine hepatopancreas tissue.
- Activities of alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD), and catalase (CAT) were measured.
- Expression levels of seven immune-related genes (LGBP, PE, α2M, AKP, ACP, CAT, Cu, Zn-SOD) were analyzed using qRT-PCR.
Main Results:
- Spiroplasma MR-1008 caused pathological changes in the prawn hepatopancreas.
- Hepatopancreas AKP and ACP activities increased significantly post-infection.
- CAT activity decreased, while SOD activity showed minor changes.
- Expression of immune-related genes, including LGBP, PE, α2M, AKP, ACP, CAT, and Cu, Zn-SOD, was induced by Spiroplasma challenge.
Conclusions:
- Spiroplasma MR-1008 can activate or inhibit immune responses in Macrobrachium rosenbergii.
- The hepatopancreas plays a critical role in the prawn's innate immunity against Spiroplasma.
- These findings provide insights into prawn immune mechanisms and potential disease control strategies.
