Investigation of Proteus vulgaris and Elizabethkingia meningoseptica invasion on muscle oxidative stress and autophagy in Chinese soft-shelled turtle (Pelodiscus sinensis)

Abstract

Muscle is an important structural tissue in aquatic animals and it is susceptible to bacterial and fungal infection, which could affect flesh quality and health. In this study, Chinese soft-shelled turtles were artificially infected with two pathogens, Proteus vulgaris and Elizabethkingia meningoseptica and the effects on muscle nutritional characteristics, oxidative stress and autophagy were assayed. Upon infection, the muscle nutritional composition and muscle fiber structure were notably influenced. Meanwhile, the mRNA expression of Nrf2 was down-regulated and Keap1 up-regulated, thus resulting in a decrease in antioxidant capacity and oxidative stress. However, with N-acetylcysteine treatment, the level of oxidative stress was decreased, accompanied by significant increases in antioxidant enzyme activities and the mRNA levels of SOD, CAT, GSTCD, and GSTO1. Interestingly, there was a significant increase in autophagy in the muscle tissue after the pathogen infection, but this increase could be reduced by N-acetylcysteine treatment. Our findings suggest that muscle nutritional characteristics were dramatically changed after pathogen infection, and oxidative stress and autophagy were induced by pathogen infection. However, N-acetylcysteine treatment could compromise the process perhaps by decreasing the ROS level and regulating Nrf2-antioxidant signaling pathways.

Mercury bioaccumulation, genotoxic and biochemical biomarkers reveal the health status of yellow-spotted Amazon River turtles (Podocnemis unifilis) in an environmental protection area in the Amazon

“…Brain and liver of the negative control group of juvenile Chrysemys picta (Schneider, 1783) subjected to hypoxia and cold contained 3.7 ± 0.4 and 2.2 ± 0.2 nanomol mg protein -1 , respectively (Baker et al 2007). Average PCA in muscle of Chinese soft-shelled turtles, Pelodiscus sinensis (Wiegmann, 1835) was 19 nanomol mg protein -1 in a group submitted to infection with two furunculosis pathogens, and 7 nanomol mg protein -1 in the control group (Li et al 2021). To our knowledge, there are no published studies on PCA related to metals in turtle muscle, but the comparison with the aforementioned studies indicates that our results for PCA (1.63 ± 0.40 nanomol mg protein -1 ) represents a low level of oxidative damage.…”

Genotypic and phenotypic analysis of Elizabethkingia meningoseptica in bullfrog Rana catesbeiana isolated in Taiwan

“…Elizabethkingia meningoseptica (previously known as Flavobacterium meningosepticum or Chryseobacterium meningosepticum ) is a Gram‐negative, oxidase‐positive and non‐glucose‐fermenting bacterium within the family Flavobacteriaceae (Kim et al, 2005). E. meningoseptica is widely distributed in nature and has been isolated from various species of aquatic animals and humans (Bernardet et al, 2005; Henriques et al, 2012; Jean et al, 2014; Li et al, 2021; Lin et al, 2019). These bacteria do not utilize any sugar like other bacteria and are capable of invading the host, causing signs such as bacteraemia in the host's nervous and digestive system, internal organ bleeding, lesions and ulcers and torticollis (Vancanneyt et al, 1994).…”