Spiroplasma ixodetis sp. nov., a New Species from Ixodes pacificus Ticks Collected in Oregon

Abstract

Eight strains of mollicutes were isolated from pooled suspensions prepared from western black-legged ticks (Ixodes puciJicus) collected in Oregon. Morphologic examination by electron and dark-field microscopic techniques showed that each strain consisted of a mixture of motile, tightly coiled helical cells, small coccoid cells with diameters ranging from 300 to 500 nm, and pleomorphic, straight or branched filamentous forms. All cellular forms were surrounded by a single cytoplasmic membrane, and there was no evidence of a cell wall. The organisms were filterable and fastidious in their growth requirements. The optimum temperature for growth was 30°C, but multiplication occurred at temperatures ranging from 23 to 32°C. The strains catabolized glucose but did not hydrolyze arginine or urea. The genome size of strain Y32T (T = type strain) was 2,220 kbp, and the DNA base composition (guanine-plus-cytosine content) of this organism was 25 k 1 mol%. The eight isolates were serologically related to each other but were not related to 37 other type or representative strains belonging to the genus Spiroplasmu. Strain Y32 (= ATCC 33835) is the type strain of Spiroplasma ixodetis sp. nov.Spiroplasmas (class Mollicutes) are helical, motile, wall-less prokaryotes that are associated with a variety of insects, other arthropods, and some plant hosts (11,38,51). Although members of the genus Spiroplasma are usually commensal organisms in their arthropod hosts, several are pathogenic for insects and plants (11, 12,24,29,30).The occurrence of spiroplasmas in hematophagous arthropods was first demonstrated in 1976 when two serologically distinct helical mollicutes (represented by strains SMCA and 277F) were identified in rabbit ticks (Haemaphysalis leporispalustris) (4,41). Strain SMCA and two related strains were eventually characterized as Spiroplasma mirum (39). Strain 277F is serologically and genomically related to Spiroplasma citri and was assigned to subgroup 1-4 in an interim classification scheme for spiroplasmas (21,36,44). Subsequently, spiroplasmas have been identified in blood-sucking members of the Diptera, including horseflies (Tabanus spp.), deerflies (Chrysops spp.), and mosquitoes (Adedes spp., Culex spp., etc.). The current status of these organisms has been summarized in several recent reviews or reports (1, 10, 15, 18, 19,38,45).We described additional isolations of tick-associated spiroplasmas in 1981 (37), including primary isolation of seven helical mollicutes from triturates of the western black-legged tick, Ixodes pacificus. While these organisms were isolated directly in SP-4 spiroplasma culture medium (43), a later report showed that most of the same isolates could be cultivated from stored triturates in several continuously maintained cultured tick cell lines (53). An extensive serologic comparison of the strains isolated from I. pacificus showed that these organisms are closely related to each other but distinct from other previously described spiroplasmas. Strain Y32T (T = type strain) was selected ...

A survey of Wolbachia, Spiroplasma and other bacteria in parthenogenetic and non-parthenogenetic phasmid (Phasmatodea) species

“…The phylogenetic characterisation of the 16S rRNA sequences of the Spiroplasma detected here ascribes the strains found in R. artemis, N. maerens, E. nuda and S. sipylus to a new divergent clade, with the ML and BI approaches (Figs 2 and 3, respectively). They appear to be associated with a 16S rRNA sequence previously described in a mite (GenBank: M24477), and classified in serogroup VI of Spiroplasma (Weisburg et al, 1989;Tully et al, 1995). This serogroup belongs to the Ixodetis clade, which includes the single lineage S. ixodetis and is at a considerable evolutionary distance from the other characterised Spiroplasma spp.…”

Incidence of the endosymbionts Wolbachia, Cardinium and Spiroplasma in phytoseiid mites and associated prey

“…Spiroplasma was found in predatory and herbivorous insects Fukatsu and Nikoh 2000;Fukatsu et al 2001;Anbutsu and Fukatsu 2003), ticks (e.g. Brinton and Burgdorfer 1976;Tully et al 1995), a parasitic dermanyssoid mite species (Reeves et al 2006), in the predatory mite N. californicus (E. Zchori-Fein et al submitted) and the herbivorous spider mite Tetranychus urticae Koch (E. Zchori-Fein et al submitted). In addition to reproductive effects the investigated bacteria can influence fecundity, longevity or activity and behaviour of their host (e.g.…”

Development of an economic rearing and transport system for an arid-adapted strain of the predatory mite, Neoseiulus californicus, for spider mite control

“…Although the first three Spiroplasma species described were plant pathogens, most of the other species known to date have been found in insects, where the symbiotic association ranges from pathogenic to mutualistic. Within the Acari, Spiroplasma has so far been identified in three tick genera (Burgdorfer et al 1973, Tully et al 1982, 1995 and a parasitic dermanyssoid mite (Reeves et al 2006), and generally its influence on the tick and mite host has not been determined.…”