Infectious particles in a marine ciliate

Soldo, A. T.; Godoy, G. A.; Brickson, S. A.

doi:10.1038/249284b0

Cited by 25 publications

(12 citation statements)

References 9 publications

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“…The presence of endosymbionts [= endocytobionts (G6rtz, 1988)] in the cytoplasm (Sonneborn, 1959;Beale et al, 1969;Preer et aI., 1974;Soldo et al, 1974;Heckmann, 1983) and/or in the nuclear apparatus (L. B. Preer, 1968;Ossipov et al, 1974;G6rtz, 1983 is the "rule" in ciliates.…”

Section: Internal Cuesmentioning

confidence: 97%

Sex in Ciliates

Dini

Nyberg

1993

Advances in Microbial Ecology

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Section: Internal Cuesmentioning

confidence: 97%

Sex in Ciliates

Dini

Nyberg

1993

Advances in Microbial Ecology

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“…In endosymbiotic associations, symbionts can b e acquired by an individual host through one of 3 ways: by acquisition of microorganisms from an environmental stock (Bauer 1981), by horizontal transn~ission (from symbiotic individual to aposymbiotic individual) (Soldo et al 1974), or by vertical transmission (from one generation to offspring) (Buchner 1965).…”

mentioning

confidence: 99%

Occurrence of bacteria in the primary oocytes of vesicomyid clam Calyptogena soyoae

Endow¹,

Ohta²

1990

Mar. Ecol. Prog. Ser.

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been introduced into eggs in cryptic forms. AmongThese bacteria resembled gill endosymbionts in the following 3 polnts: dimensions and general outllne, occurrence of elecdeep-sea tZlftia pachyptila was tron-transparent vacuoles in the periplasm, and occurrence of establish syn~biosis by talung up bacteria from freeelectron-dense materials in the periplasm. Eggs which harbored bacteria were all in the vitellogenic stage. This finding suggests some restricted time schedule of the entry of bacteria into oocytes. It is hypothesized that these bacteria represent transmission stage of gill symbionts, and continuum of the symbiosis is maintained by maternal inheritance through egg infection.

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“…Xenosomes from stock 263-20 (nonkiller) and 110-3 (killer) were used to infect xenosome-free stocks 263-20 and 110-3 of P. acutum. The stocks to be infected were cured of their symbionts by treatment with tetracycline (13). The cured stocks were judged symbiont free by (i) failure to observe xenosomes in the cytoplasm after aceto-orcein staining, (ii) inability of filtrates of stock 110-3 (killer) to kill susceptible Uronema nigricans, and (iii) inability of filtrates of stocks 110-3 (killer) and 263-20 (nonkiller) to infect homologous and heterologous strains of P. acutum.…”

Section: Resultsmentioning

confidence: 99%

“…Several stocks of the marine protozoan Paraiuronema acutum contain intracytoplasmic symbiotic bacteria which grow and divide in synchronism with the host (13). The symbionts, which we have termed xenosomes, sensu strictu, are obligate parasites and cannot be cultured outside the protozoan.…”

mentioning

confidence: 99%

Association of transformation of xenosomes from nonkiller to killer with extrachromosomal DNA

Soldo¹,

Brickson²,

Castiglione³

et al. 1986

J Bacteriol

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Extrachromosomal DNA in the form of covalently closed circular DNA molecules was isolated from killer and nonkiller xenosomes, bacterial endosymbionts of the marine protozoan Parauronema acutum. Restriction endonuclease digests of these molecules derived from 12 isolates revealed consistent, readily identifiable, differences in the pattern of fragments of the killer as compared with those present in the nonkiller. Transformation of the nonkiller to killer by infection is also accompanied by a change from the nonkiller to killer pattern. Based on analysis of fragments resulting from restriction endonuclease digests, two circular duplex DNA molecules, each 63 kilobase pairs (kbp) in length, were identified in the 263-20 nonkiller stock and mapped. The maps revealed that each possesses a single BamHI site and multiple Bgll, BstIIE, PstI, and Sall sites. A distinguishing feature of these maps is that the two molecules share a region about 17 kbp in length in which multiple restriction sites are in register with each other. Allowing for a 0.5-kbp insertion or deletion and the introduction or removal of only a few restriction sites, an additional stretch extending approximately 31 kbp beyond this sequence could also be considered to be homologous. The structure of the killer plasmid appears to be more complex, and we have been unable, as yet, to construct physical maps for this DNA. We postulate that the killer plasmid DNA is composed of three, perhaps four, circular 63-kbp duplexes, at least one which contains a single BamHI site and another which contains two BamHI sites. The remaining molecules may represent copies of either or both of the other two, modified to contain additional restriction sites. Transformation from the nonkiller to the killer is visualized as the insertion of restriction sites at various points along parent nonkiller plasmid DNA molecules. The mechanism by which these sites are introduced is unknown.Several stocks of the marine protozoan Paraiuronema acutum contain intracytoplasmic symbiotic bacteria which grow and divide in synchronism with the host (13). The symbionts, which we have termed xenosomes, sensu strictu, are obligate parasites and cannot be cultured outside the protozoan. Xenosomes released from the cytoplasm by mechanical rupture of the host cell are capable of infecting homologous and heterologous strains of P. acutuem as well as one other marine protozoan, Miamiensis aliidus Ma. Xenosomes from some stocks (killers) are capable of killing certain marine protozoa of the genus Uronema as evidenced by exposure of these organisms to breis of symbiont-bearing P. acutum. We show here that xenosomes from other stocks of P. acutum (nonkillers) do not have this capacity. Significantly, P. acutum is insensitive to the toxin produced by the killer xenosomes. In an effort to determine the mechanism responsible for the killer effect and to establish its molecular basis, we previously examined chromosomal DNA derived from killer and nonkiller xenosomes by DNA-DNA hybridization (9). Whereas a h...

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Infectious particles in a marine ciliate

Cited by 25 publications

References 9 publications

Sex in Ciliates

Sex in Ciliates

Occurrence of bacteria in the primary oocytes of vesicomyid clam Calyptogena soyoae

Association of transformation of xenosomes from nonkiller to killer with extrachromosomal DNA

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