Chemical defense by means of pigmented extrusomes in the ciliate Blepharisma japonicum

Harumoto, Terue; Miyake, Akio; Ishikawa, Naoko; Sugibayashi, Rika; Zenfuku, Kazutaka; lio, Hideo

doi:10.1016/s0932-4739(98)80014-x

Cited by 52 publications

(65 citation statements)

References 37 publications

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“…Dileptus margaritifer, formerly D. anser, stock SHL-BB , was cultured in SMB and fed with a small ciliate, Sathrophilus sp., grown in boiled lettuce medium inoculated with Enterobacter aerogenes 2 days before use (Miyake & Beyer 1973). Blepharisma japonicum Suzuki, 1954 stock R1072 (Harumoto et al 1998), Paramecium tetraurelia Sonneborn, 1975 stock 51 (Miyake et al 2003), Spirostomum ambiguum Ehrenberg, 1835 stock Pol-5 (collected in Policoro, Italy) and Spirostomum teres Claparede et Lachmann, 1858 stock Pol-1 (Buonanno 2005), were cultured in bacterized culture medium. Didinium nasutum stock 7771 (derived from the strain 30399 purchased from the American Type Culture Collection) was cultured in SMB and fed with P. tetraurelia.…”

Section: Methodsmentioning

confidence: 99%

The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates

Buonanno

Ortenzi

2010

Biologia

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Climacostol (5-(Z)-non-2-enyl-benzene-1,3-diol) is a natural toxin isolated from the freshwater ciliated protozoan Climacostomum virens and belongs to resorcinolic lipids, a group of compounds that show antimicrobial, antiparasitic, and anticancer activities. We investigated the cytotoxic activity of the chemically synthesized toxin and its alkyl and alkynyl derivatives on C. virens and nine other common species of free-living freshwater ciliates. Our results show that the cytotoxic potency of climacostol can be modulated by the substitution of the double bond present in the aliphatic chain of the toxin with a single or a triple one that was previously obtained during the synthesis of the unsaturated and saturated derivatives of the parent molecule. We demonstrated that the cytotoxicity level of the molecules considered in this study appears to be inversely correlated to the unsaturation level of their aliphatic chains, and that the potency of their action is also related to the target organism.

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Section: Methodsmentioning

confidence: 99%

The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates

Buonanno

Ortenzi

2010

Biologia

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“…380 × 40 µm) stock Pol-1 (Buonanno 2005) and Blepharisma japonicum (approx. 350 × 150 µm) stock R1072 (Harumoto et al 1998) were cultured in bacterized culture medium. Debris in the cultures were removed as described in Miyake & Honda (1976) using a nylon net with a mesh size appropriate to the respective organism.…”

Section: Organisms and Culturesmentioning

confidence: 99%

“…An example is given by the inducible defenses where ciliates in the genus Euplotes may show phenotypic and behavioral changes induced by the release of an active kairomone from the predator (Kuhlmann & Heckmann 1985, 1994Kush 1993;Hammil et al 2009). Instead other ciliates are able to release some secondary metabolites (toxins) from peculiar organelles called "extrusomes" to ward off potential predators including microturbellarians (Harumoto et al 1998;Buonanno 2005;Buonanno et al 2005). Extrusomes are membrane-bound organelles that ciliates evolved in association with their cortex, and have the unique capacity to be discharged in response to a variety of environmental stimuli (Hausmann 1978).…”

Section: Introductionmentioning

confidence: 99%

The changes in the predatory behavior of the microturbellarian Stenostomum sphagnetorum on two species of toxin-secreting ciliates of the genus Spirostomum

Buonanno

2011

Biologia

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It is known that the microturbellarian Stenostomum sphagnetorum, a common ciliate predator, is very sensitive against different types of toxins produced by other ciliates for chemical defense, and consequently, it is not able to capture and ingests these ciliates. In particular, when the predator tries to attack one of these toxin-secreting ciliates, it is forced to regurgitate the captured prey in response to the toxin discharged from the ciliates. In this study it is shown that after repeated attacks by S. sphagnetorum against two species of toxic ciliates (Spirostomum ambiguum and Spirostomum teres), the predator acquires a behavior of prey selection that leads to the exclusion of these ciliates among the possible prey and to the distinction between edible and inedible (toxic) ciliates. This learned behavior, which is maintained for days, is lost only after the asexual reproduction of the microturbellarian. In addition, S. sphagnetorum learns to recognize and avoid specimens of S. ambiguum and S. teres artificially deprived of their toxins, strongly suggesting that the toxins are not exclusively associated in the prey recognition of the microturbellarian.

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“…Isolation of total RNA B. japonicum has red pigments (blepharismine) that are presumed to play the roles of photoreception and/or defense against predators (Giese, 1973a;Harumoto et al, 1998). Because trace amounts of pigments often hamper the process of extraction of RNA, we prepared pigment-depleted cells by cold treatment as described (Sugiura and Harumoto, 2001).…”

Section: Methodsmentioning

confidence: 99%

Developmentally and environmentally regulated expression of gamone 1: the trigger molecule for sexual reproduction inBlepharisma japonicum

Sugiura

Kawahara

Iio

et al. 2005

Journal of Cell Science

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Sexual reproduction (conjugation) in protozoan ciliates is induced by specific cell-cell interactions between cells of complementary mating types. The ancestral ciliate Blepharisma japonicum has two mating types, I and II. The substances that act as signaling molecules in this extracellular interaction for conjugation are called gamones. The glycoprotein gamone 1, produced by mating type I cells, is a key factor that triggers this interaction. We have previously isolated gamone 1 and determined its complete amino acid sequence. To elucidate the mechanism of initiation of conjugation in ciliates, we investigated the transcription of the gamone 1 gene and found that it is controlled by various internal and external factors. The gamone 1 gene transcript appeared specifically when sexually mature mating type I cells were starved. It was not detected in immature cells, mating type II cells or proliferating cells. The level of transcription was markedly increased in type I cells when they were stimulated with gamone 2, which is secreted by type II cells. This is the first report that the transcription of gamone genes in ciliates is strictly regulated by developmental and environmental factors. This study suggests that the onset of transcription of gamone 1 is linked to the switching mechanism that converts mitotically proliferating cells to differentiated preconjugants, the mechanism of differentiation from immature to mature cells in clonal development, and the mechanism that ensures mating type-specific gene silencing.

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Chemical defense by means of pigmented extrusomes in the ciliate Blepharisma japonicum

Cited by 52 publications

References 37 publications

The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates

The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates

The changes in the predatory behavior of the microturbellarian Stenostomum sphagnetorum on two species of toxin-secreting ciliates of the genus Spirostomum

Developmentally and environmentally regulated expression of gamone 1: the trigger molecule for sexual reproduction inBlepharisma japonicum

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