The Effects of Certain Chemicals on the Macronucleus of Spirostomum teres, with Notes on the Genus

Packard, Charles

doi:10.2307/3223194

Cited by 3 publications

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“…Specimens that have recently gone through division or conjugation have fewer nodules, and micronuclei with smaller diameters compared with more mature cells. Internal factors (e.g., cytoplasmatic pressure) or external (e.g., chemical composition) can also alter the shape of the macronucleus in S. teres (PACKARD 1948). In the present study, the presence of a macronuclear groove housing one micronucleus was observed in some specimens of S. teres (Fig.…”

Section: Molecular Characterizationmentioning

confidence: 51%

“…PACKARD (1948) performed a morphological study of the nuclear apparatus of S. teres and observed a relationship between age since division and number of macronuclear nodules. Specimens that have recently gone through division or conjugation have fewer nodules, and micronuclei with smaller diameters compared with more mature cells.…”

Section: Molecular Characterizationmentioning

confidence: 99%

“…Spirostomum was mentioned for the first time by EHRENBERG (1838) and morphological studies have been subsequently carried out for some species (PACKARD 1948, FINLEY et al 1964, DANIEL & MATTERN 1965, TUFFRAU 1967, KUDO 1971. However, these studies were based exclusively on observations of specimens in vivo.…”

mentioning

confidence: 99%

“…heavy metals like nickel, copper, mercury, and zinc; the phenol Na-PCP) (MADONI et al 1992, MADONI 2000. Nevertheless, studies on the morphology and taxonomy of Spirostomum species are quite rare (PACKARD 1948, FINLEY et al 1964, DANIEL & MATTERN 1965, TUFFRAU 1967, KUDO 1971, REPAK & ISQUITH 1974, FOISSNER et al 1992.…”

mentioning

confidence: 99%

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Morphology and 18S rDNA gene sequence of Spirostomum minus and Spirostomum teres (Ciliophora: Heterotrichea) from Rio de Janeiro, Brazil

Fernandes¹,

Silva‐Neto²

2013

Zoologia (Curitiba)

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ABSTRACT. Species of Spirostomum Ehrenberg, 1838 are widely used as model organisms in ecological studies of environmental impacts and symbioses between ciliates and human pathogenic bacteria. However, the taxonomy of this genus is confused by the superficiality of the morphological descriptions of its included species, and the use of only a few characters for their differentiation. The present study provides details of total infraciliature, nuclear apparatus, morphometric data and 18S rDNA gene sequences of Spirostomum teres Claparède & Lachmann, 1858 and Spirostomum minus Roux, 1901, isolated from a sewage treatment plant and a freshwater lake in the city of Rio de Janeiro, Brazil, respectively. For the morphological descriptions of S. teres and S. minus, living cells were observed using bright-field and differential interference contrast (DIC) microscopy, the total infraciliature and nuclear apparatus were revealed by staining with protargol, and ciliary patterns were observed also with scanning electron microscopy (SEM). and colorless cytoplasm. Evidence from 18S rDNA sequences confirms the identification of S. teres and suggests the existence of cryptic species closely related to S. minus. The use of silver impregnation technique (protargol) allowed the observation and description of a greater number of characters in S. minus and S. teres, thus assisting the research that require identification of these species.

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Section: Molecular Characterizationmentioning

confidence: 51%

Section: Molecular Characterizationmentioning

confidence: 99%

mentioning

confidence: 99%