Chemotaxis without Conventional Two-Component System, Based on Cell Polarity and Aerobic Conditions in Helicity-Switching Swimming of Spiroplasma eriocheiris

Abstract

Spiroplasma eriocheiris is a pathogen that causes mass mortality in Chinese mitten crab, Eriocheir sinensis. S. eriocheiris causes tremor disease and infects almost all of the artificial breeding crustaceans, resulting in disastrous effects on the aquaculture economy in China. S. eriocheiris is a wall-less helical bacterium, measuring 2.0 to 10.0 μm long, and can swim up to 5 μm per second in a viscous medium without flagella by switching the cell helicity at a kink traveling from the front to the tail. In this study, we showed that S. eriocheiris performs chemotaxis without the conventional two-component system, a system commonly found in bacterial chemotaxis. The chemotaxis of S. eriocheiris was observed more clearly when the cells were cultivated under anaerobic conditions. The cells were polarized as evidenced by a tip structure, swimming in the direction of the tip, and were shown to reverse their swimming direction in response to attractants. Triton X-100 treatment revealed the internal structure, a dumbbell-shaped core in the tip that is connected by a flat ribbon, which traces the shortest line in the helical cell shape from the tip to the other pole. Sixteen proteins were identified as the components of the internal structure by mass spectrometry, including Fibril protein and four types of MreB proteins.

Identification of proteome, antigen protein and antigen membrane protein fromSpiroplasma eriocheiris

“…2.3.02) against the S. eriocheiris genome (Liu et al . ). Functional annotations of the proteins were conducted using Blast2GO program against the nonredundant protein database (NR; NCBI).…”

“…; Liu et al . ). Screening of these immunogenic proteins was established using immunoprecipitation and LC‐MS/MS.…”

Phylogenetic origin and sequence features of MreB from the wall-less swimming bacteria Spiroplasma

“…citri, and S. eriocheiris), all of which swim via similar kink propagations [5,7,8,9,10,11,13,28]. The duplication and deletion of SMreBs in the Apis group may suggest their diverse swimming formats.…”

Tree of motility – A proposed history of motility systems in the tree of life

“…A small group of organisms, class Mollicutes, which has evolved from the phylum Firmicutes including Bacillus and Clostridium, have acquired three distinct motility mechanisms (Miyata & Hamaguchi, 2016a). These are the gliding motility (Bredt & Radestock, 1977;Miyata, 2010;Miyata & Hamaguchi, 2016b) displayed by Mycoplasma mobile, which is a pathogen of freshwater fish, a second type of gliding motility (Figure 1; type 16) (Bredt, 1968;Miyata & Hamaguchi, 2016a) used by Mycoplasma pneumoniae in humans ( Figure 1; type 17), and the swimming motility of Spiroplasma (Figure 1; type 18) (Cole, Tully, Popkin, & Bove, 1973;Liu et al, 2017;Shaevitz, Lee, & Fletcher, 2005;Wada & Netz, 2009), a common pathogen of plants and arthropods.…”