Spiroplasma diminutum sp. nov., from Culex annulus Mosquitoes Collected in Taiwan

Abstract

Initially, strain CUAS-lT (T = type strain), which was isolated from a frozen triturate of Culex annulus mosquitoes collected in Taiwan, was thought to be a member of spiroplasma group VII. This placement was based on the spiroplasma deformation test titer observed when strain CUAS-lT spiroplasmas were tested with Spiroplasma monobiue MQ-lT antiserum. The results of subsequent reciprocal spiroplasma deformation, metabolism inhibition, and growth inhibition tests clearly revealed that strain CUAS-lT is not serologically related to previously described spiroplasma groups (groups I to XXIV) and thus is a representative of a new group, group XXV. Strain CUAS-lT was characterized by using the minimal standards for mollicute species descriptions. During logarithmic-phase growth, strain CUAS-lT cells are characteristically very short helices with 1.5 to 2 helical turns (1 to 2 pm), highly motile, and bounded by a single trilaminar membrane and form granular colonies with satellites when the organism is grown aerobically on MID medium containing 1.6% agar. Growth in M1D broth occurs at temperatures ranging from 10 to 37"C, and the optimum temperature is 30°C. Substrate utilization tests revealed that cholesterol is required for growth, that glucose is hydrolyzed, and that arginine is not hydrolyzed both in the presence and in the absence of glucose. The genome of strain CUAS-lT is 1,080 kbp long, and the guanine-plus-cytosine content is 26 & 1 mol%. On the basis of the results of our studies we propose that strain CUAS-lT (group XXV) should be placed in a new species, Spiropfasmu diminutum. Strain CUAS-1 (= ATCC 49235) is the type strain of S. diminutum.The first mosquito spiroplasma was isolated from a triturate of female salt marsh mosquitoes (Aedes sollicitans) (12). This organism was subsequently characterized and named Spiroplasma culicicola (8). Mosquitoes have proved to be a rich source of spiroplasmas, and the following two additional mosquito-derived spiroplasmas have been characterized: Spiroplasma sabaudiense (1) and Spiroplasma taiwanense (2). In addition, several spiroplasma strains isolated from mosquitoes collected in France and the United States have recently been shown to be related to each other and to be members of three subgroups of group XVI (3). A previously existing collection of frozen mosquito triturates originally collected by one of us (L.R.) for a mosquito-borne virus survey in Southeast Asia (People's Republic of China, Japan, Taiwan) has been found to contain, in addition to S. taiwanense, several spiroplasma strains that cannot be placed in previously described species. One of these triturates (triturate 250657) was derived from 83 Culex annulus adult female mosquitoes collected in Taishan, Taiwan, in 1980. The spiroplasmas found in this triturate (designated strain CUAS-lT [T = type strain]) were studied because of their small size and rapid growth in broth medium, * Corresponding author. Phone: (516) traits shared with the mosquito-derived organism Spiroplasma culicicola AES-lT. The res...

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

“…For example, S. sabaudiense is the only species that has the complete set of genes for arginine utilization ( arcA , arcB , and arcC ), which is consistent with previous biochemical tests (Abalain-Colloc et al 1987; Hung et al 1987; Abalain-Colloc et al 1988; Williamson et al 1996). Additionally, sucrose utilization ( scrB and scrK ) appears to be limited to S. diminutum , while glycerophosphocholine (GPC; substrate of glpU and glpQ ) utilization appears to be limited to S. culicicola .…”

“…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.…”

Plant Virus–Insect Vector Interactions: Current and Potential Future Research Directions

“…While Spiroplasma can be pathogenic in mosquitoes, their role in mosquito competence to vector viruses remains to be determined [132,133,134]. In contrast, Wolbachia pipientis has antiviral effects in both naturally infected and experimentally infected insects.…”

Spiroplasma spp.: A Plant, Arthropod, Animal and Human Pathogen

“…USA (MD) [12] Spiroplasma diminutum Mosquito (Culex annulus) Taiwan [13] Spiroplasma eriocheiris Chinese mitten crab (Eriocheir…”