Mode of action of glyphosate in Candida maltosa

Bode, R.; Melo, Carlos R.; Birnbaum, D.

doi:10.1007/bf00409776

Cited by 41 publications

(19 citation statements)

References 14 publications

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“…Glyphosate at micromolar concentrations is a competitive inhibitor of substrate (phosphoenol pyruvate) binding by 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase (Haslam 1993), which occurs late in the pathway, just prior to the chorismate branchpoint leading to essential aromatic amino acids, inter alia. At millimolar concentrations it also inhibits the first two steps in the pathway-3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase and 3-dehydroquinate (DHQ) synthase (Bode et al 1984). This is important because in the biosynthetic scheme proposed by Favre-Bonvin et al (1987), the carbon ring structure of mycosporines is derived from DHQ produced early in the pathway, well before the EPSP synthase-catalyzed step.…”

Section: Discussionmentioning

confidence: 99%

Ultraviolet‐B radiation stimulates shikimate pathway‐dependent accumulation of mycosporine‐like amino acids in the coral Stylophora pistillata despite decreases in its population of symbiotic dinoflagellates

Shick

Romaine-Lioud

Ferrier‐Pagés

et al. 1999

Limnology & Oceanography

200

152

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Colonies of Stylophora pistillata maintained for four years in indoor aquaria in the near absence of ultraviolet radiation (UVR) contained only small amounts (Ͻ5 nmol mg Ϫ1 protein) of 10 identified mycosporine-like amino acids (MAAs, which act as UV sunscreens), the largest number reported in any organism. The concentrations of most MAAs increased linearly or exponentially when colonies were exposed to ultraviolet-A (UVA) and ultraviolet-B (UVB) for 8 h dϪ1 in the presence of photosynthetically active radiation (PAR). Total MAA concentration reached 174 nmol mg Ϫ1 protein after 30 d, with palythine and mycosporine-2 glycine constituting more than half of the final total. UVB specifically stimulated MAA accumulation: after 15 d, MAA levels in colonies exposed to PAR alone and to PAR and UVA did not differ (7 and 5 nmol MAA mg Ϫ1 protein, respectively), while those in colonies exposed to PAR and UVA ϩ UVB were significantly higher (28 nmol mg Ϫ1 protein). Glyphosate, an inhibitor of the shikimate pathway, eliminated or reduced the UV-induced accumulation of most MAAs during 7 d of exposure, providing the first experimental evidence of their synthesis via this pathway in a coral symbiosis. Densities of zooxanthellae in colonies of S. pistillata, Acropora sp., and Seriatopora hystrix exposed to UVR for 15 d were only one-third of those in control colonies unexposed to UVR. This net decrease in the number of zooxanthellae in the corals (bleaching) occurred despite UV-stimulated increases in algal cytokinesis and in the host cell-specific density of zooxanthellae in hospite, increases that apparently destabilized the symbiosis and caused expulsion of the zooxanthellae.

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Section: Discussionmentioning

confidence: 99%

Ultraviolet‐B radiation stimulates shikimate pathway‐dependent accumulation of mycosporine‐like amino acids in the coral Stylophora pistillata despite decreases in its population of symbiotic dinoflagellates

Shick

Romaine-Lioud

Ferrier‐Pagés

et al. 1999

Limnology & Oceanography

200

152

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“…Metabolic conversion of MAAs-An ongoing biosynthesis of primary MAAs would complicate the analysis of the stoichiometry of their conversion to secondary MAAs, so 1 mmol L Ϫ1 glyphosate was used to block the shikimate pathway, presumably at the first two enzymes (Bode et al 1984;Shick and Dunlap 2002). Once applied, glyphosate inhibited any further increase in primary, Symbiodinium MAAs (Fig.…”

Section: Effect Of Continuity Of Uv Stimulus On Accumulation Ofmentioning

confidence: 99%

The continuity and intensity of ultraviolet irradiation affect the kinetics of biosynthesis, accumulation, and conversion of mycosporine‐like amino acids (MAAs) in the coral Stylophora pistillata

Shick

2004

Limnology & Oceanography

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Colonies of Stylophora pistillata unexposed to ultraviolet radiation (UVR) in laboratory aquaria contained minimal amounts of mycosporine-like amino acids (MAAs). The concentration of MAAs increased rapidly during exposure to broadband UVR, then stabilized between 14 and 28 d of exposure. The four MAAs known to be produced by diverse zooxanthellae (Symbiodinium spp.) in culture were the first to increase in coral colonies, followed by six additional MAAs. Decreases in these four primary MAAs between days 14 and 28 were balanced by stoichiometric increases in the six secondary MAAs, suggesting a precursor-product relationship. Discontinuing UV exposure caused rapid declines in the concentrations of primary MAAs, while secondary MAAs continued to increase, likely a manifestation of different rates of turnover of the putative enzymes involved in the de novo biosynthesis of primary MAAs and their conversion to secondary MAAs. The continued production of certain MAAs after UV exposure ceased indicates that UV is not required catalytically but is a signal that induces the enzymes of the biosynthetic pathway. Biochemically inhibiting the biosynthesis of primary MAAs after a pool of these MAAs had accumulated did not affect their conversion to secondary MAAs. Doubling the UV irradiance increased the rate of accumulation, first, of primary MAAs and, later, of secondary MAAs. Under normal UV irradiance, the eventual decline in the accumulation rate of primary MAAs was quantitatively explained by their conversion to secondary MAAs. Under doubled UV irradiance, where MAA concentrations were higher, the deceleration of accumulation of primary MAAs was twice as great as the acceleration in secondary MAAs, suggesting a regulation of the de novo biosynthesis of MAAs, perhaps by their own progressive, concentration-dependent attenuation of UVR.

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“…Jaworsky, 1972;Haderlie et al, 1977;Gresshoff, 1979;Hollander & Amrhein, 1980; among others). Glyphosate caused a massive accumulation of shikimate in treated cells and tissues Berlin & Witte, 1981;Bode et al, 1984;Rubin et al, 1984). These studies narrowed the possible site of action to three enzymes, involved in the conversion of shikimate to chorismate.…”

Section: Mode Of Action and Biochemistrymentioning

confidence: 99%

Effects of Herbicide Glyphosate and Glyphosate-Based Formulations on Aquatic Ecosystems

Pérez¹,

Vera²,

Miranda³

2011

Herbicides and Environment

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Mode of action of glyphosate in Candida maltosa

Cited by 41 publications

References 14 publications

Ultraviolet‐B radiation stimulates shikimate pathway‐dependent accumulation of mycosporine‐like amino acids in the coral Stylophora pistillata despite decreases in its population of symbiotic dinoflagellates

Ultraviolet‐B radiation stimulates shikimate pathway‐dependent accumulation of mycosporine‐like amino acids in the coral Stylophora pistillata despite decreases in its population of symbiotic dinoflagellates

The continuity and intensity of ultraviolet irradiation affect the kinetics of biosynthesis, accumulation, and conversion of mycosporine‐like amino acids (MAAs) in the coral Stylophora pistillata

Effects of Herbicide Glyphosate and Glyphosate-Based Formulations on Aquatic Ecosystems

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