Effects of Ca2+ and K+ on motility and photomotility of the marine ciliate Fabrea salina

✍ Scribed by Spartaco Puntoni; Roberto Marangoni; Domenico Gioffré; Giuliano Colombetti

• Book ID: 104373323
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 432 KB
• Volume: 43
• Category: Article
• ISSN: 1011-1344
• DOI: 10.1016/s1011-1344(98)00109-2

✦ Synopsis

Fabrea salina is a motile ciliate marine protozoan belonging to the order Heterotrichida that shows photomotile reactions. We report here the results of a study on motility and phototaxis of F. salina exposed to different Ca 2+ and K ÷ concentrations. Our findings show that concentrations of potassium ions greater than that of the growth medium and concentrations of calcium ions lower than that of the growth medium cause a significant increase in phototactic response, while the cell speed is not significantly affected. A more thorough analysis shows that the absolute concentrations of Ca 2÷ or K ÷ are not important and that the phototactic responsiveness depends mainly on the ratio of the K ÷ concentration to the square root of the Ca 2 + (the so-called Ja value), in agreement with the results obtained in other protozoa. Our results are tentatively discussed in terms of altered membrane potential or ion channel conductances.