Blepharmone: A Conjugation-Inducing Glycoprotein in the Ciliate
            <i>Blepharisma</i>

Miyake, Akio; Beyer, Jens

doi:10.1126/science.185.4151.621

Cited by 72 publications

(26 citation statements)

References 14 publications

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“…On average, 200-300 μg of homogenous protein were extracted from 10 L of culture filtrate. The purified material was stored at −20°C after lyophilization, and no significant loss of activity was observed, as verified by mating induction assays (41 (42). The En-A1 molecular structure was calculated following a standard protocol consisting of seven automated cycles of the ATNOS/CANDID/DYANA programs (43)(44)(45), and subsequent energy-minimization in explicit water with the program OPALp (46,47).…”

Section: Methodsmentioning

confidence: 99%

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Giuseppe

Erra

Dini

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Wild-type strains of the protozoan ciliate Euplotes collected from different locations on the coasts of Antarctica, Tierra del Fuego and the Arctic were taxonomically identified as the morpho-species Euplotes nobilii, based on morphometric and phylogenetic analyses. Subsequent studies of their sexual interactions revealed that mating combinations of Antarctic and Arctic strains form stable pairs of conjugant cells. These conjugant pairs were isolated and shown to complete mutual gene exchange and cross-fertilization. The biological significance of this finding was further substantiated by demonstrating that close homology exists among the threedimensional structures determined by NMR of the water-borne signaling pheromones that are constitutively secreted into the extracellular space by these interbreeding strains, in which these molecules trigger the switch between the growth stage and the sexual stage of the life cycle. The fact that Antarctic and Arctic E. nobilii populations share the same gene pool and belong to the same biological species provides new support to the biogeographic model of global distribution of eukaryotic microorganisms, which had so far been based exclusively on studies of morphological and phylogenetic taxonomy.ciliate mating types and sexual interactions | microbial ecology | NMR structures | polar biology | signaling by water-borne pheromones

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Section: Methodsmentioning

confidence: 99%

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Giuseppe

Erra

Dini

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…Gamone 1 (blepharmone) has also been isolated (20) and reported to be a glycoprotein with a molecular mass of about 20 or 30 kDa (by column chromatography and SDS͞PAGE, respectively) consisting of 175 amino acids and 6 sugar residues (20,21). However, this chemical composition was calculated based on the relative amounts of different residues measured with an amino acid analyzer (for amino acids and amino sugars) and gas-liquid chromatograph (for neutral sugars).…”

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confidence: 99%

Identification, characterization, and complete amino acid sequence of the conjugation-inducing glycoprotein (blepharmone) in the ciliate Blepharisma japonicum

Sugiura

Harumoto

2001

Proc. Natl. Acad. Sci. U.S.A.

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Conjugation in Blepharisma japonicum is induced by interaction between complementary mating-types I and II, which excrete blepharmone (gamone 1) and blepharismone (gamone 2), respectively. Gamone 1 transforms type II cells such that they can unite, and gamone 2 similarly transforms type I cells. Moreover, each gamone promotes the production of the other gamone. Gamone 2 has been identified as calcium-3-(2-formylamino-5-hydroxybenzoyl) lactate and has been synthesized chemically. Gamone 1 was isolated and characterized as a glycoprotein of 20 -30 kDa containing 175 amino acids and 6 sugars. However, the amino acid sequence and arrangement of sugars in this gamone are still unknown. To determine partial amino acid sequences of gamone 1, we established a method of isolation based on the finding that this glycoprotein can be concentrated by a Con A affinity column. Gamone 1 is extremely unstable and loses its biological activity once adsorbed to any of the columns that we tested. By using a Con A affinity column and native PAGE, we detected a 30-kDa protein corresponding to gamone 1 activity and determined the partial amino acid sequences of the four peptides. To isolate gamone 1 cDNA, we isolated mRNA from mating-type I cells stimulated by synthetic gamone 2 and then performed rapid amplification of cDNA ends procedures by using gene-specific primers and cloned cDNA of gamone 1. The cDNA sequence contains an ORF of 305 amino acids and codes a possibly novel protein. We also estimated the arrangement of sugars by comparing the affinity to various lectin columns.

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“…For example, sex pheromones permit individuals to locate or recognize partners of the opposite sex (Miyake and Beyer 1974;Stanhope et al 1992;Snell et al 1993). Chemicals that accumulate with increasing population density (crowding chemicals) provide information about the likelihood of male-female encounters.…”

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confidence: 99%

Induction of sexual reproduction in Brachionus plicatilis (Monogononta, Rotifera) by a density‐dependent chemical cue

Stelzer

Snell

2003

Limnology & Oceanography

120

103

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Induction of sexual reproduction in Brachionus plicatilis (Monogononta, Rotifera) by a density-dependent chemical cue Abstract-Induction of mixis (sexual reproduction) in rotifers of the genus Brachionus is believed to be triggered by a chemical that is released into the water and accumulates at high population densities. However, direct and conclusive evidence for this hypothesis is thus far lacking. In this study, two mass cultures of the rotifer Brachionus plicatilis were monitored as they grew from low to high population densities. Conditioned water was prepared daily from these cultures, and females were exposed in a bioassay, which consisted of juvenile Brachionus, cultured individually in large volumes that would normally suppress mixis. Conditioned water induced mixis in the bioassay at rates comparable to those found in the mass cultures. Both in bioassay and mass cultures, mixis was essentially absent in the beginning of the experiment, when population densities were very low. The first mictic females appeared at densities of 0.1 females ml Ϫ1 , and their proportion increased rapidly as the populations grew to Ͼ1 female ml Ϫ1 . The maximum rates of mixis in the bioassay were highly significant and reached 51% of those observed in the mass cultures. These results strongly support the hypothesis that mixis in Brachionus plicatilis is induced by a density-dependent chemical cue.

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Blepharmone: A Conjugation-Inducing Glycoprotein in the Ciliate Blepharisma

Cited by 72 publications

References 14 publications

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Identification, characterization, and complete amino acid sequence of the conjugation-inducing glycoprotein (blepharmone) in the ciliate Blepharisma japonicum

Induction of sexual reproduction in Brachionus plicatilis (Monogononta, Rotifera) by a density‐dependent chemical cue

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