Characterization of the Species of the Tetrahymena pyriformis Complex

Nanney, D. L.; McCoy, John W.

doi:10.2307/3225391

Cited by 306 publications

(116 citation statements)

References 37 publications

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“…Some of these complexes also include asexual strains that can be characterised by SSU rRNA gene sequences. The genetic distances between these sibling species may be slight or large (Nanney & McCoy 1976, Nanney et al 1998. In some cases, rather subtle functional differences have been suggested to characterise individual cryptic species.…”

Section: 'Cryptic' Speciesmentioning

confidence: 99%

Cosmopolitan microbes and their cryptic species

Fenchel¹

2005

Aquat. Microb. Ecol.

101

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The notion that microbial species have cosmopolitan distribution is discussed for protists in light of the considerable genetic variation within nominal species. It is concluded that there is no compelling evidence to indicate that different genotypes ('cryptic species') have biogeographies or that they originated through allopatric speciation. It is suggested that variation in rRNA gene sequences reflects accumulated neutral mutations which do not necessarily reflect functional diversity. The fundamental value of the species concept is that it provides information on the organism in terms of phenotypic properties.

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Section: 'Cryptic' Speciesmentioning

confidence: 99%

Cosmopolitan microbes and their cryptic species

Fenchel¹

2005

Aquat. Microb. Ecol.

101

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“…Doerder et al (1995) indicate a high frequency of conjugation in Tetrahymena thermophyla, based on immaturity of freshly collected clones; indirect, a posteriori, evidence of conjugation. In contrast, Nanney & McCoy (1976) indicated, within natural populations of the Tetrahymena pyriformis complex, the existence of large numbers of asexual strains, which can constitute 30 to 50% of the overall strains collected in nature.…”

Section: Discussionmentioning

confidence: 99%

How often does conjugation in ciliates occur? Clues from a seven-year study on marine sandy shores

Lucchesi¹,

Santangelo²

2004

Aquat. Microb. Ecol.

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Conjugation is a distinctive process of ciliate sexual reproduction, and while its induction and progression have been widely investigated in lab-cultured strains of several species, little information has been gathered about the actual frequency of this sexual process in natural habitats. This study focuses on the frequency of conjugation in ciliates dwelling on Mediterranean sandy shores. Over the period 1990 to 1996, 680 sand samples (1 ml) were collected along Italian coasts and examined just after collection for the presence of conjugating pairs. Overall, the samplings yielded 28 890 individual ciliates belonging to 121 species, but only 20 conjugating pairs belonging to 8 different species. Conjugation, therefore, seems to be an erratic sexual phenomenon and not as frequent in ciliates of temperate marine sandy shores as previously thought.

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“…Phosphorylation other than at the 5' position has not been reported for TK. Brawerman and Chargaff (5) report that T. pyriformis (species designation under the new nomenclature [18] is not known) NPT in a crude extract will produce 3'-and 5'-CMP, using 5'-inosinic acid or phenylphosphate as a phosphate donor and cytidine as an acceptor. High-pressure liquid chromatography of the reaction products from the assay of T. thermophila TK and NPT revealed only 5'-TMP when ATP and 5'-AMP were used as the respective phosphate donors and thymidine was used as the substrate (Table 4).…”

Section: Resultsmentioning

confidence: 99%

Mutant strains of Tetrahymena thermophila defective in thymidine kinase activity: biochemical and genetic characterization.

Cornish¹,

Pearlman²

1982

Mol. Cell. Biol.

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Three mutant strains, one conditional, of Tetrahymena thermophila were defective in thymidine phosphorylating activity in vivo and in thymidine kinase activity in vitro. Nucleoside phosphotransferase activity in mutant cell extracts approached wild-type levels, suggesting that thymidine kinase is responsible for most, if not all, thymidine phosphorylation in vivo. Thymidine kinase activity in extracts of the conditional mutant strain was deficient when the cells were grown or assayed or both at the permissive temperature, implying a structural enzyme defect. Analysis of the reaction products from in vitro assays with partially purified enzymes showed that phosphorylation by thymidine kinase and nucleoside phosphotransferase occurred at the 5' position. Genetic analyses showed that the mutant phenotype was recessive and that mutations in each of the three mutant strains did not complement, suggesting allelism.

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Characterization of the Species of the Tetrahymena pyriformis Complex

Cited by 306 publications

References 37 publications

Cosmopolitan microbes and their cryptic species

Cosmopolitan microbes and their cryptic species

How often does conjugation in ciliates occur? Clues from a seven-year study on marine sandy shores

Mutant strains of Tetrahymena thermophila defective in thymidine kinase activity: biochemical and genetic characterization.

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Characterization of the Species of the Tetrahymena pyriformis Complex

Cited by 306 publications

References 37 publications

Cosmopolitan microbes and their cryptic species

Cosmopolitan microbes and their cryptic species

How often does conjugation in ciliates occur? Clues from a seven-year study on marine sandy shores

Mutant strains of Tetrahymena thermophila defective in thymidine kinase activity: biochemical and genetic characterization.

Contact Info

Product

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Cosmopolitan microbes and their cryptic species

Cosmopolitan microbes and their cryptic species