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Titolo:
Calcium is involved in the gravitactic orientation in colorless flagellates
Autore:
Richter, P; Lebert, M; Tahedl, H; Hader, DP;
Indirizzi:
Univ Erlangen Nurnberg, Inst Bot & Pharmazeut Biol, D-91058 Erlangen, Germany Univ Erlangen Nurnberg Erlangen Germany D-91058 -91058 Erlangen, Germany
Titolo Testata:
JOURNAL OF PLANT PHYSIOLOGY
fascicolo: 6, volume: 158, anno: 2001,
pagine: 689 - 697
SICI:
0176-1617(200106)158:6<689:CIIITG>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
EUGLENA-GRACILIS; CELL-SHAPE; INDICATORS; TRANSDUCTION; CALMODULIN; CHANNELS; GREEN;
Keywords:
Astasia longa; calcium; Calcium Crimson; dynamic calcium imaging; Euglena gracilis; gravitaxis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Hader, DP Univ Erlangen Nurnberg, Inst Bot & Pharmazeut Biol, Staudstr 5, D-91058 Erlangen, Germany Univ Erlangen Nurnberg Staudstr 5 Erlangen Germany D-91058 many
Citazione:
P. Richter et al., "Calcium is involved in the gravitactic orientation in colorless flagellates", J PLANT PHY, 158(6), 2001, pp. 689-697

Abstract

The colorless flagellate Astasia longa shows a pronounced negative gravitaxis. The calcium fluorescence indicator Calcium Crimson was used to detect changes of the intracellular calcium concentration during gravitactical orientation. Astasia shows an increase of the fluorescence after a lag phase of about 10 s, a maximum after about 30 s and a decrease to the basic level within 60 s during gravitactic reorientation. The observed change in fluorescence corresponds to an almost doubling of the initial free calcium concentration. The influence of inhibitors, known to impair gravitaxis, on the calcium concentration of Astasia longa was tested. Addition of caffeine, an inhibitor of phosphodiesterase, increases, while addition of gadolinium, an inhibitor of mechanosensitive ion channels decreases the fluorescence signal. While gravitactic stimulation of caffeine-treated cells resulted in a kinetics of fluorescence intensity changes comparable to control cells the addition of gadolinium inhibited any calcium concentration change. Dynamic fluorescence imaging was used during a sounding rocket experiment (MAXUS 3 campaign). Different accelerations interrupted by mug intervals were applied to Astasia cells. The cells show an increase in the calcium signal upon acceleration and a decrease during the mug state. The results strongly reemphasize the working model of gravitaxis which is based on the activation of mechano-sensitive ion channels as one of the primary events in signal perception.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/21 alle ore 00:56:47