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Titolo:
BAPTA-CALCIUM BUFFERS MODULATE CELL PLATE FORMATION IN STAMEN HAIRS OF TRADESCANTIA - EVIDENCE FOR CALCIUM GRADIENTS
Autore:
JURGENS M; HEPLER LH; RIVERS BA; HEPLER PK;
Indirizzi:
UNIV MASSACHUSETTS,DEPT BIOL AMHERST MA 01003 UNIV MASSACHUSETTS,DEPT BIOL AMHERST MA 01003
Titolo Testata:
Protoplasma
fascicolo: 1-4, volume: 183, anno: 1994,
pagine: 86 - 99
SICI:
0033-183X(1994)183:1-4<86:BBMCPF>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIVIDING PLANT-CELLS; CAULONEMA TIP CELLS; ENDOPLASMIC-RETICULUM; CAFFEINE INHIBITION; PLASMA-MEMBRANE; CYTOKINESIS; EXOCYTOSIS; FUNARIA; ANAPHASE; MITOSIS;
Keywords:
BAPTA; CELL PLATE; CYTOKINESIS; FREE CA2+ GRADIENT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
54
Recensione:
Indirizzi per estratti:
Citazione:
M. Jurgens et al., "BAPTA-CALCIUM BUFFERS MODULATE CELL PLATE FORMATION IN STAMEN HAIRS OF TRADESCANTIA - EVIDENCE FOR CALCIUM GRADIENTS", Protoplasma, 183(1-4), 1994, pp. 86-99

Abstract

Five BAPTA buffers with differential affinities for Ca2+ have been examined for their effects on cell plate formation in stamen hair cells of Tradescantia. The five include 5,5'-dimethyl BAPTA (Kd = 0.15 mu M), BAPTA (Kd = 0.22 mu M), 5,5'-dibromo BAPTA (Kd = 1.5 mu M), 5-methyl,5'-nitro BAPTA (Kd = 22 mu M), and 5-nitro BAPTA (Kd = 40 mu M). At aconcentration of 5 mM and 25 mM in the pipette, the buffers were iontophoretically microinjected into dividing stamen hair cells (2 nA for 1 min) prior to or at the onset of cell plate formation. At the lowestconcentration (5 mM), only one buffer, 5,5'-dibromo BAPTA, inhibits cell plate formation, and is most effective if delivered at the moment of cell plate vesicle aggregation. The inhibitory effects appear as a slowing of cell plate expansion, the formation of distorted plates, orthe complete dissolution of plates that might have initiated normally. When the pipette tip concentration is elevated to 25 mM, the effectsof 5,5'dibromo BAPTA become more profound. At these levels 5,5'-dimethyl BAPTA, BAPTA, and 5-nitro BAPTA also modulate cell plate formation, producing effects similar to that of 5,5'-dibromo BAPTA at the lowerconcentration. Independent studies using fura-2 as a fluorescent analogue of the BAPTA buffers, indicate that the apparent effective concentration for 5,5'-dibromo BAPTA is between 1.0-1.4 mM; its threshold concentration is not known but expected to be somewhat lower. For the other buffers the threshold concentration is between 1.5-2.2 mM. The concentration dependence supports the idea that the buffers facilitate diffusion of Ca2+ away from regions of elevated concentration. The results thus provide evidence that local Ca2+ gradients may be present in the vicinity of the cell plate and that they participate in the cytokinetic process.

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Documento generato il 03/04/20 alle ore 20:18:38