Climacostomum

Climacostomum
Climacostomum sp.
Scientific classification
Domain:
Eukaryota
(unranked):
SAR
(unranked):
Alveolata
Phylum:
Ciliophora
Class:
Heterotrichea
Order:
Heterotrichida
Family:
Climacostomidae
Genus:
Climacostomum

Stein, 1859
Species

Climacostomum virens
Climacostomum gigas, meunier 1907

Climacostomum is a genus of unicellular ciliates, belonging to the class Heterotrichea.

The genus has one well-described species, Climacostomum virens, which usually carries a symbiotic alga, a variety of Chlorella that can be cultivated outside its host.[1] Algae-free (aposymbiotic) individuals are known, and a species that lacks algal symbionts, Climacostomum gigas Meunier 1907, has been identified, but not confirmed in recent literature.

In its cortex, Climacostomum virens has colorless granules structurally similar to the defensive pigmentocysts found in its fellow Heterotrichs, Stentor coreuleus and Blepharisma japonicum.[2] When Climacostomum is threatened by a predator, such as the ciliate Dileptus margaritifer, these cortical cysts release a defensive cytotoxin called Climacostol. This substance has been synthesized in the laboratory[3] and found to be highly toxic to certain species of ciliates.[4] It is believed that this toxicity is accomplished by the inhibition of mitochondrial respiration.[5] It has been shown to have toxic effects on certain human cancer cells.[6]

  1. ^ Reisser, W.; Fischer-Defoy, D.; Staudinger, J.; Schilling, N.; Hausmann, K. (1984). "The endosymbiotic unit ofClimacostomum virens andChlorella sp. I. Morphological and physiological studies on the algal partner and its localization in the host cell". Protoplasma. 119 (1–2): 93–9. doi:10.1007/BF01287821. S2CID 21463062.
  2. ^ Miyake, A (2003). "Chemical defence by means of extrusive cortical granules in the heterotrich ciliate". European Journal of Protistology. 39: 25–36. doi:10.1078/0932-4739-00900.
  3. ^ Abe, Yumi; Mori, Kenji (2001). "Simple Synthesis of Climacostol, a Defensive Secretion by the Ciliate Climacostomum virens". Bioscience, Biotechnology, and Biochemistry. 65 (9): 2110–2. doi:10.1271/bbb.65.2110. PMID 11676032.
  4. ^ Buonanno, Federico; Ortenzi, Claudio (2010). "The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates". Biologia. 65 (4): 675–80. doi:10.2478/s11756-010-0071-1. S2CID 757779.
  5. ^ Muto, Yoshinori; Tanabe, Yumiko; Kawai, Kiyoshi; Okano, Yukio; Iio, Hideo (2010). "Climacostol inhibits Tetrahymena motility and mitochondrial respiration". Central European Journal of Biology. 6: 99–104. doi:10.2478/s11535-010-0100-7.
  6. ^ Buonanno, Federico; Quassinti, Luana; Bramucci, Massimo; Amantini, Consuelo; Lucciarini, Roberta; Santoni, Giorgio; Iio, Hideo; Ortenzi, Claudio (2008). "The protozoan toxin climacostol inhibits growth and induces apoptosis of human tumor cell lines". Chemico-Biological Interactions. 176 (2–3): 151–64. doi:10.1016/j.cbi.2008.07.007. PMID 18723007.