Spiroplasma clarkii sp. nov. from the Green June Beetle (Coleoptera: Scarabaeidae)

Abstract

Spiroplasma strain CN-ST (T = type strain), isolated from the gut of the cetoniine scarabaeid beetle Cotinus nitidiz, was serologically distinct from other spiroplasma species, groups, and subgroups. Cells of strain CN-ST were shown by light microscopy to be helical, motile filaments. Cells in early passages exhibited strong translational motility that tended to be lost in later passages. Electron microscopy showed that the cells were bounded by a single cytoplasmic membrane with no evidence of a cell wall. The organism was not susceptible to penicillin. Strain CN-ST grew well in SM-1, MlD, and SP-4 liquid media and on solid SP-4 medium under aerobic or anaerobic conditions. The doubling time at 30"C, the optimum temperature, was 4.3 h. The strain also grew in 1% serum fraction medium. Strain CN-ST produced acid from glucose and catabolized arginine, but did not hydrolyze urea. The guanine-plus-cytosine content of the DNA was 29 f 1 mol%. The genome size was 1,770 kb (1,186 MDa). Other uncloned isolates obtained from C. nitida or the cetoniine hermit flower beetle Osmoderma eremicola exhibited similar or identical serological patterns. Since no other hosts were discovered in extensive studies, strain CN-ST (previously designated group IX) appears to represent a cluster of relatively host-specific cetoniine beetle-associated strains. Strain CN-5 (= ATCC 33827) is designated the type strain of a new species, Spiroplasma clarkii.

Horizontal Gene Acquisitions Contributed to Genome Expansion in Insect-Symbiotic Spiroplasma clarkii

“…The complete genome sequence of S. clarkii contains one circular chromosome that is 1.56 Mb in size; no plasmid was found. Although this size is 12% smaller than the 1.77 Mb estimate based on PFGE ( Whitcomb et al. 1993 ), it is still >30% larger than the median of other Apis clade species with complete genome sequences available ( fig.…”

“…1995 ). Given these general observations, it is interesting to note that Spiroplasma clarkii , a facultative symbiont residing in the gut of larval/adult Scarabaeidae beetles without apparent effect on its host, was found to have a genome size that is >30% larger than the median of other species within the same clade ( Whitcomb et al. 1993 ).…”

Gut bacteria of adult and larval Cotinis nitida Linnaeus (Coleoptera: Scarabaeidae) demonstrate community differences according to respective life stage and gut region

“…In this gut yeast floral community, Trichosporon cutaneum is most abundant in the gut of adult beetle and has been shown to play a relatively important role in the behavioral biology of adult beetles by producing volatile semiochemicals that serve as aggregation pheromones ( Vishniac and Johnson, 1990 ; Johnson and Vishniac, 1991 ). Similarly, a species of Spiroplasma , S. clarkii , has been cultured from the guts of both adult and larval C. nitida ( Whitcomb et al, 1993 ). It is the aim of this work to identify the bacterial diversity of the green June beetle, and to test for community partitioning based on gut region, sex, and life stages in C. nitida through the analysis of 16S rRNA gene high-throughput amplicons.…”

Heterogeneity of Genome Sizes within the Genus Spiroplasma

“…Previously, the genome sizes of the following Spiroplasma species have been determined: Spiroplasma citri (1,820 kbp), Spiroplasma apis (1,350 kbp), Spiroplasma melliferum (1,460 kbp) , Spiroplasma insolitum (1,850 kbp) , Spiroplasma clarkii (1,770 kbp), and Spiroplasma monobiae (940 kbp) (13,16,47,48,52,53). In this study we determined, by using PFGE, the genome sizes of representatives of all spiroplasma groups except groups 11, XIV, and XXIII.…”