Induction of Polarity in Fucoid Zygotes.

Kropf, Darryl L.

doi:10.1105/tpc.9.7.1011

Cited by 109 publications

(75 citation statements)

References 45 publications

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“…The Ca 2ϩ signal at the rhizoid apex is essential for turgor and volume regulation (13) and probably involves the regulation of ion channels that allow osmoregulatory ion efflux (24). Polarized growth requires localized Ca 2ϩ elevation, transduced via Ca 2ϩ ͞calmodulin (25,26), regulation of targeted exocytosis (27), and a functional cytoskeleton (28). Studies with the Mn 2ϩ quench technique revealed a role for Ca 2ϩ influx in the generation of Ca 2ϩ signals in the rhizoid apex (13).…”

Section: Resultsmentioning

confidence: 99%

Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength

Goddard

Manison

Tomos

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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Section: Resultsmentioning

confidence: 99%

Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength

Goddard

Manison

Tomos

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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“…Fucales have long been good models for investigating brown alga and land plant embryogenesis. Given its large size and its ease of manipulation, the Fucales zygote has been particularly amenable to cytological and pharmacological experiments (Kropf, 1997). Polarization of the zygote after fertilization involves several subcellular components (cell wall, microtubules, centrioles, and actin; for review, see Kropf, 1992) and is affected by auxin, which alters the polarity of the embryo and its developmental pattern (Basu et al, 2002;Sun et al, 2004).…”

mentioning

confidence: 99%

Auxin Metabolism and Function in the Multicellular Brown AlgaEctocarpus siliculosus

et al. 2010

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Ectocarpus siliculosus is a small brown alga that has recently been developed as a genetic model. Its thallus is filamentous, initially organized as a main primary filament composed of elongated cells and round cells, from which branches differentiate. Modeling of its early development suggests the involvement of very local positional information mediated by cell-cell recognition. However, this model also indicates that an additional mechanism is required to ensure proper organization of the branching pattern. In this paper, we show that auxin indole-3-acetic acid (IAA) is detectable in mature E. siliculosus organisms and that it is present mainly at the apices of the filaments in the early stages of development. An in silico survey of auxin biosynthesis, conjugation, response, and transport genes showed that mainly IAA biosynthesis genes from land plants have homologs in the E. siliculosus genome. In addition, application of exogenous auxins and 2,3,5-triiodobenzoic acid had different effects depending on the developmental stage of the organism, and we propose a model in which auxin is involved in the negative control of progression in the developmental program. Furthermore, we identified an auxin-inducible gene called EsGRP1 from a small-scale microarray experiment and showed that its expression in a series of morphogenetic mutants was positively correlated with both their elongated-to-round cell ratio and their progression in the developmental program. Altogether, these data suggest that IAA is used by the brown alga Ectocarpus to relay cell-cell positional information and induces a signaling pathway different from that known in land plants.

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“…Polarity can be observed within 14-16 h AF when the rhizoid protuberance appears on the zygote surface. The rhizoid appearance is preceded by a series of processes, including asymmetric ion fluxes (Homblé and Léonetti 2007), redistribution of cytoskeletal elements (e.g., Bisgrove and Kropf 2001a, Bisgrove et al 2003) and targeted vesicular secretion (Kropf 1997). Subsequently, the zygote has a single axis of symmetry that defines the embryo growth axis, and normally the first division of the zygote is perpendicular to this axis and positioned by telophase nuclei (Bisgrove and Kropf 2004).…”

Section: Morphological Responsesmentioning

confidence: 99%

“…The induction of axis polarity in fucoid zygotes has been extensively investigated (e.g., Quatrano 1974, Kropf 1997, Homblé and Léonetti 2007. Fucoid eggs have spherical shape and are initially apolar.…”

Section: Morphological Responsesmentioning

confidence: 99%

Effect of GeO₂on embryo development and photosynthesis in Fucus vesiculosus (Phaeophyceae)

Tarakhovskaya¹,

Kang²,

Kim³

et al. 2012

ALGAE

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Germanium dioxide (GeO 2 ) has been used for many years in the cultivation of red and green algae as a means of controlling the growth of diatoms. Brown algae are sensitive to GeO 2 , however, the basis of this sensitivity has not been characterized. Here we use embryos of Fucus vesiculosus to investigate morphological and physiological impacts of GeO 2 toxicity. Morphometric features of embryos were measured microscopically, and physiological features were determined using pulse amplitude modulated (PAM) fluorometry. At 5 mg L -1 GeO 2 , embryos grew slower than controls and developed growth abnormalities. After 24 h, initial zygote divisions were often oblique rather than transverse. Rhizoids had inflated tips in GeO 2 and were less branched, and apical hairs were deformed, with irregularly aligned, spheroidal cells. Minimum fluorescence (F 0 ) showed minor differences over the 10 days experiment, and pigment levels (chlorophylls a, c and total carotenoids) showed no difference after 10 days. Optimum quantum yield increased from ca. 0.52 at 24 h to 0.67 at 5 days, and GeO 2 -treated embryos had higher mean values (significant at 3 and 5 days). Optimum quantum yield of photosystem II (Φ PSII ) was stable in control thalli after 5 days, but declined significantly in GeO 2 . Addition of silica (as SiO 2 ) did not reverse the effects of GeO 2 . These results suggest that GeO 2 toxicity in brown algae is associated with negative impacts at the cytological level rather than metabolic impacts associated with photosynthesis.

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Induction of Polarity in Fucoid Zygotes.

Cited by 109 publications

References 45 publications

Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength

Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength

Auxin Metabolism and Function in the Multicellular Brown AlgaEctocarpus siliculosus

Effect of GeO₂on embryo development and photosynthesis in Fucus vesiculosus (Phaeophyceae)

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Induction of Polarity in Fucoid Zygotes.

Cited by 109 publications

References 45 publications

Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength

Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength

Auxin Metabolism and Function in the Multicellular Brown AlgaEctocarpus siliculosus

Effect of GeO2on embryo development and photosynthesis in Fucus vesiculosus (Phaeophyceae)

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Effect of GeO₂on embryo development and photosynthesis in Fucus vesiculosus (Phaeophyceae)