Isolation, characterization and virulence of Mesanophrys sp. (Ciliophora: Orchitophryidae) in farmed swimming crab (Portunus trituberculatus) in eastern China

Abstract

Swimming crab (Portunus trituberculatus) is an important crab species cultured in China, which is also widely found in Japan and North Korea (Dai, Feng, Song, Huang, & Wu, 1977). With the development of farming, the P. trituberculatus industry is gradually threatened by various diseases, such as virus diseases (P. trituberculatus reovirus disease [

Effect of environmental factors on survival and population growth of ciliated parasite,Mesanophryssp. (Ciliophora: Scuticociliatia) infectingPortunus trituberculatus

“…Our study also agrees with Liu et al . 's (2020) report that the parasitosis outbreak occurred with many parasites in haemocytes of dying swimming crab where the water temperature was 12–15°C. Therefore, we hypothesized that wintering temperature probably may facilitate this Mesanophrys sp.…”

“…This trial was repeated in four replicates. The cultured ciliates were observed and photographed using a differential interference contrast microscope (Nikon), and total length/width was measured by using a micrometer (Julia et al ., 2007; Liu et al ., 2020) (data: mean ± s.d. , n = 4).…”

“…Scuticociliate systemic infection in crustacean species has received comparatively more attention due to its harmful effects (Morado and Small, 1995) on American lobster, freshwater crayfish and krill (Edgerton et al ., 1996; Cawthorn, 1997; Gómez-Gutiérrez et al ., 2003). Recently, protistan Mesanophrys sp., a newly identified scuticociliate species, was successfully detected from DNA and other molecular studies of damaged haemocytes of cultured overwintering swimming crab ( Portunus trituberculatus ) (Liu et al ., 2020). Genus Mesanophrys parasites were also reported in crab and isopods species (Armstrong et al ., 1981; Morado and Small, 1994; Wiąckowski et al ., 1999), this triggers economic losses to the native farmers and affects artificial breeding of swimming crab in Eastern China (Yu et al ., 2020).…”

Dynamic Distribution of Mesanophrys sp. and Tissue Enzyme Activities in Experimentally Infected Mud Crab Scylla paramamosain

“…DNA was extracted using DNA Kit (Axygen A Corning Brand, Suzhou, China); the target gene of Mesanophrys sp. was amplified using forward primer (ITS1-5.8s-ITS2F and ITS1-5.8s-ITS2R) [11] (Table 1). Quantitative real-time PCR assays were carried out in triplicate in a 20 µL final volume that included 1 µL of DNA template, 10 µL 2 × of MagicSYBR Mixture (CWBIO, Beijing, China), 0.4 µL of each primer (10 µM) and 8.2 µL of nuclease-free water.…”

“…Most Mesanophrys ciliates feed on bacteria and organic debris [7] and grow quickly through a two-division proliferation mode. However, they can also invade the hemolymphs of crustaceans and consume the lysate there in order to proliferate; intense infection causes damage to the internal organs and finally leads to death, which may cause serious economic losses to local farmers and enterprises [8][9][10][11]. In early 2017, a new parasite, Mesanophrys sp., emerged in an artificial nursery farm of Portunus trituberculatus in Ningbo, Zhejiang Province, resulting in more than 80% mortality among the P. trituberculatus [12].…”