Spiroplasma taiwanense sp. nov. from Culex tritaeniorhynchus Mosquitoes Collected in Taiwan

Abstract

Spirophsmu isolates recovered from female mosquitoes (Culex tritueniorhynchus) collected in Taiwan werefound to be similar in their serological properties. Strain CT-lT (T = type strain) proved to be serologically unrelated to all currently recognized spiroplasma groups and subgroups. Strain CT-lT was studied by using criteria proposed by the International Committee on Systematic Bacteriology Subcommittee on Taxonomy of Mollicutes for the description of new mollicute species. The organisms were shown to belong to the class Mollicutes by the ultrastructure of their limiting membrane, their colonial morphology, and their filtration patterns and to the family Spiroplusmatuceue by their helical morphology and motility. Growth in SP-4, MlA, and M1D media occurred at 22 to 30°C. Cholesterol was required for growth. Glucose was fermented, but arginine was not hydrolyzed. The base composition (guanine-plus-cytosine content) of the deoxyribonucleic acid of strain CT-lT was found to be 25 f 1 mol%. On the basis of these findings, we propose that spiroplasma strains with these characteristics should be recognized as a new species, Spiroplusmu tuiwunense. Strain CT-lT has been deposited in the American Type Culture Collection as strain ATCC 43302T.In July 1981, female mosquitoes were collected in Taiwan in a survey of a natural population of mosquitoes for the presence of Japanese encephalitis virus @a). In 1985, triturates of these mosquitoes, which had been stored at -7O"C, were tested for the possible presence of spiroplasmas by culture in SP-4 medium. Several isolates of helical motile organisms were obtained in these trials. One of the spiroplasma isolates was designated strain CT-lT (T = type strain) to reflect the name of the mosquito species (Culex tritaeniorhynchus) from which it had been isolated. Strain CT-lT was shown to be distinct from all previously described group I through XXI strains by one-way deformation, metabolism inhibition, and growth inhibition tests and was designated the representative strain of a new group, group XXII, according to the classification originally proposed by Junca et al. (17) and subsequent revisions (27,33,34). Two additional spiroplasma strains, CT-2 and CT-3, isolated in the same year from the same species of mosquito at the same site, had titers similar to those of strain CT-lT when they were tested against CT-lT antiserum in one-way deformation tests.In this report, we summarize evidence that strain CT-lT and related strains fulfill the minimal species requirements for Mollicutes as proposed by the International Committee on Systematic Bacteriology Subcommittee on the Taxonomy of Mollicutes (16, 32). Therefore, we formally propose that strain CT-lT and related strains be recognized as a new species in the genus Spiroplasma. MATERIALS AND METHODSOrigin of strain. Female mosquitoes attracted to animal bait near rice fields were collected at Taishan (near Taipei), * Corresponding author.Taiwan, Republic of China, on 2 July 1981. After capture, mosquitoes were held for 4 days to ...

Comparison of Metabolic Capacities and Inference of Gene Content Evolution in Mosquito-Associated Spiroplasma diminutum and S. taiwanense

“…The S. taiwanense genome contains a circular plasmid that is 11,138 bp in size and encodes 11 protein-coding genes (1 SOJ-like protein and 10 hypothetical proteins); no plasmid was found in the S. diminutum genome. The chromosomal GC contents are consistent with previous estimates obtained using biochemical methods, with S. diminutum having a GC content of 25.5% (Williamson et al 1996) and S. taiwanense having a GC content of 23.9% (Abalain-Colloc et al 1988). Both genomes contain a single ribosomal RNA gene cluster, which corresponds to the highest peak observed in the GC content plot (fig.…”

“…The three characterized strains of S. taiwanense (CT-1 T , CT-2, and CT-3) were all isolated from C . tritaeniorhynchus (Abalain-Colloc et al 1988). The two characterized strains of S. diminutum , CUAS-1 T and CT-4, were isolated from C .…”

“…sticticus and A . vexans collected in the French Northern Alps (Abalain-Colloc et al 1987), and two species from mosquitoes collected in Taiwan: S. taiwanense from Culex tritaeniorhynchus (Abalain-Colloc et al 1988) and S. diminutum from C. annulus and C. tritaeniorhynchus (Williamson et al 1996). Interestingly, artificial infection experiments revealed that these Spiroplasma species exhibit different levels of pathogenicity toward their mosquito hosts.…”

16S rRNA Gene-Based Identification of Midgut Bacteria from Field-Caught Anopheles gambiae Sensu Lato and A. funestus Mosquitoes Reveals New Species Related to Known Insect Symbionts

“…The bacterial DNA clones from mosquito D2.2 represent the fifth Spiroplasma species found in mosquitoes. It does not group with any of the previously known mosquito spiroplasmas, Spiroplasma culicicola (19), Spiroplasma diminutum (34), Spiroplasma saubaudiense (1), or Spiroplasma taiwanense (2), in the phylogenetic analysis (Fig. 1B) and phylogenetic analysis using PAUP (not shown).…”

Molecular Evolution of the Substrate Utilization Strategies and Putative Virulence Factors in Mosquito-Associated Spiroplasma Species

“…To date five characterized Spiroplasma species have been found to be associated with mosquitoes, including Spiroplasma culicicola (Hung et al 1987), S. sabaudiense (Abalain-Colloc et al 1987), S. taiwanense (Abalain-Colloc et al 1988), S. cantharicola (Whitcomb et al 1993), and S. diminutum (Williamson et al 1996). All of these five Spiroplasma species belong to the Apis clade within the genus.…”