Biological and Physical Properties of the Suckling Mouse Cataract Agent Grown in Chicken Embryos

Bastardo, Jesús W.; Ou, David; Bussell, Robert H.

doi:10.1128/iai.9.2.444-451.1974

Cited by 14 publications

(4 citation statements)

References 24 publications

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“…43:163, 1969). In addition, it is our view that EM observations from other laboratories (3,26) utilizing thin-sectioning and negative-staining techniques also support the conclusion that the agent is probably of the Mycoplasmatales order.…”

Section: Discussionsupporting

confidence: 70%

“…It was presumed that the SMCA was of a viral nature because (i) light microscopy had failed to detect evidence of the presence of organisms in infected tissues (5); (ii) the agent has been uncultivable, to date, in a variety of artificial media known to support bacterial and mycoplasmal growth (H F. Clark, Progr. Med. Virol., in press; 5); (iii) the SMCA will pass through membrane filters (Millipore Corp.) of 220-nm pore size but not of 100-nm pore size (5,26); and (iv) the SMCA is persistently capable of inducing infection in the presence of penicillin and streptomycin (5) and a variety of broad-spectrum antibiotics (H F. Clark,in press;3,26).…”

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confidence: 99%

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Electron Microscopy of the Suckling Mouse Cataract Agent: a Noncultivable Animal Pathogen Possibly Related to Mycoplasma

Zeigel

Clark

1974

Infect Immun

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The suckling mouse cataract agent (SMCA) is a filtrable (<220 nm), noncultivable agent isolated from ticks in Georgia in 1961. It grows to high titer in the eyes and brains of intracerebrally inoculated mice in which it induces cataract, uveitis, and chronic brain infection. SMCA in high titer may also be recovered from the tissues of embryonated hen eggs in which the infection is lethal within 4 to 9 days. Fine-structural studies of ultrathin sections of pellets obtained by ultracentrifugation of SMCA-infected egg allantoic fluids have revealed pleomorphic structures with morphological characteristics typical of mycoplasma. Similar organisms have been observed in egg allantoic fluids infected with an SMCA-related tick isolate, GT-48, but not in fluids from uninoculated control eggs. Mycoplasma-like entities were also observed in high concentration within retinal tissues of rats and mice studied at the time of maximal retinitis and uveitis after SMCA inoculation. Comparable tissues from normal mouse eyes were free of microorganisms. These fine-structural observations are in agreement with those reported by other investigators and suggest that SMCA-induced pathology is associated with an agent that resembles mycoplasma in size and morphology but differs from typical mycoplasma in its apparent non-cultivability on artificial media and its resistance to inactivation by broad-spectrum antibiotics.

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Section: Discussionsupporting

confidence: 70%

mentioning

confidence: 99%

Electron Microscopy of the Suckling Mouse Cataract Agent: a Noncultivable Animal Pathogen Possibly Related to Mycoplasma

Zeigel

Clark

1974

Infect Immun

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“…Initial attempts were made to cultivate S. mirum in cell culture but were unsuccessful for cytopathic effects as well as for multiplication of the organism (1,3). Chick embryo chorioallantoic membrane and yolk sac fragment cultures were unsuccessful (3).…”

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confidence: 99%

Characterization of Spiroplasma mirum (suckling mouse cataract agent) in a rabbit lens cell culture

Mégraud¹,

Gamon²,

McGarrity³

1983

Infect Immun

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Spiroplasma mirum (suckling mouse cataract agent) was studied in an epithelial cell line AG-4676, derived from rabbit eye lens. Rabbit eye lens is a natural target tissue of S. mirum infection. The organism grew rapidly in this cell line, reaching titers of 10(7) to 10(9) color change units per ml at 7 days after infection. This is the same level as that achieved in SP-4 medium designed specifically for S. mirum. No lag period was apparent in growth in AG-4676. S. mirum did not grow in Dulbecco minimal essential medium-10% fetal bovine serum, the medium for AG-4676, indicating the need for cells or a cellular product. S. mirum-infected AG-4676 cells exhibited vacuolization and granulation and an increase in polynucleation compared with uninfected controls (36/100 versus 14/100, P less than 0.001). Infection significantly decreased the growth rate of AG-4676, especially late in the growth cycle. In a representative experiment, growth of AG-4676 at 11 days was reduced from 9 X 10(5) to 2 X 10(4) cells by S. mirum infection. S. mirum grew to high titers in conditioned medium of AG-4676, obtained from cell-free supernatants of 1- to 5-day-old AG-4676 cultures. This growth promotion was not due to osmotic conditioning of the medium. Preliminary characterization of this growth promotion substance showed it to be active after 0.22-micron filtration, heating at 56 degrees C for 30 min, freezing and thawing, and dilution at 10(-1) but not 10(-2). AG-4676-propagated S. mirum produced death or cataracts in suckling Wistar rats at the same frequency (55/60, 91.7%) as SP-4-propagated organisms (60/65, 92.3%).

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“…Spiroplasmas were also isolated from ticks (25)(26)(27)(28)(29). One of the tick isolates, S. mirum, is referred to as the suckling mouse cataract agent due to its ability to establish experimental infections and disease in suckling mice (27,28,(30)(31)(32). As research on spiroplasmas proceeded and more isolates were characterized, it became apparent that insects served as the major reservoir for spiroplasma maintenance and dispersal (14,15), and that plant surfaces were more important in dispersal and transmission than the plant phloem (33)(34)(35).…”

Section: Introductionmentioning

confidence: 99%

Spiroplasmas: evolutionary relationships and biodiversity

Laura¹

2006

Front Biosci

133

104

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Spiroplasmas are wall-less descendants of Gram-positive bacteria that maintain some of the smallest genomes known for self-replicating organisms. These helical, motile prokaryotes exploit numerous habitats, but are most often found in association with insects. Co-evolution with their insect hosts may account for the highly speciose nature of the genus Spiroplasma, with many spiroplasmas existing in obligate insect/plant transmission cycles. In addition to insect and plant hosts, spiroplasmas are found in association with ticks and crustaceans. Although most spiroplasma associations appear to be commensal, some cases of pathogenicity or mutualism have been described. Most notably, spiroplasmas have been identified as the causative agents of agricultural and aquacultural diseases and the sex ratio disorder in insects. Some spiroplasmas exhibit strict host and/or geographical ranges, but others are relative generalists. Species of the genus Spiroplasma have been traditionally classified into 34 groups based on cross-reactivity of surface antigens. Three of the serogroups contain closely related strain complexes that are further divided into subgroups. Phylogenetic reconstructions based on 16S rDNA sequence strongly support the closely related serogroups. To date, less than 40 Spiroplasma species have been fully characterized and given binomial names. Complete characterization of a new species involves numerous phenotypic and genotypic tests as outlined in the minimal standards document; this document is currently under revision to include phylogenetic data and a reevaluated set of required phenotypic and genotypic tests. The area of spiroplasma research is poised for major advances with new criteria for naming species in preparation, a dramatic increase in available molecular characters, the promise of full genome sequences, and advances in genetic tools for manipulation of these organisms.

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Biological and Physical Properties of the Suckling Mouse Cataract Agent Grown in Chicken Embryos

Cited by 14 publications

References 24 publications

Electron Microscopy of the Suckling Mouse Cataract Agent: a Noncultivable Animal Pathogen Possibly Related to Mycoplasma

Electron Microscopy of the Suckling Mouse Cataract Agent: a Noncultivable Animal Pathogen Possibly Related to Mycoplasma

Characterization of Spiroplasma mirum (suckling mouse cataract agent) in a rabbit lens cell culture

Spiroplasmas: evolutionary relationships and biodiversity

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