The Shikimate Pathway — A Metabolic Tree with Many Branche

Bentley, Ronald; Haslam, Edwin

doi:10.3109/10409239009090615

Cited by 685 publications

(470 citation statements)

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“…MAAs are a suite of 19 compounds with absorption maxima at 310 -360nm. They are produced de novo via the shikimate pathway in algae, fungi, and bacteria (Bentley, 1990), and animals are assumed to acquire MAAs through diet or symbioses with these organisms . MAAs have been found in adults from a variety of organisms including algae, fish, cnidarians, molluscs, and echinoderms (reviewed by ).…”

Section: Introductionmentioning

confidence: 99%

A Quantitative Survey of Mycosporine-Like Amino Acids (MAAS) in Intertidal Egg Masses from Temperate Rocky Shores

2005

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Abstract-Mycosporine-like amino acids (MAAs) have been reported as functional chemical sunscreens in a variety of marine organisms, but their role in development of marine larvae remains largely unexplored. In this study, we quantified MAAs from intertidal egg masses of 46 species of mollusc, two species of polychaete, and one species of fish from southeastern Australia. We sought to elucidate potential patterns of occurrence and variation based on egg mass maturity, adult diet, spawning habitat, phylogeny, and viability. Our analyses revealed that maturity and spawning habitat did not significantly affect MAA composition within egg masses. In contrast, adult diet, phylogeny, and viability significantly affected MAA composition. Herbivores had significantly higher levels of certain MAAs than carnivores; similarly, viable egg masses had higher levels of some MAAs than inviable egg masses. MAA composition varied according to taxonomic group, with nudibranchs and anaspids showing different MAA composition to that of neogastropods, sacoglossans, and polychaetes. Basommatophoran egg masses had significantly more porphyra-334 than the other groups, and anaspids had more mycosporine-2-glycine than the other groups. MAAs occurred in relatively high concentrations in intertidal molluscan egg masses when compared to adult molluscs and other common intertidal organisms. Despite the complexity of factors affecting MAA composition, the prevalence of MAAs in some species is consistent with protection afforded to offspring against negative effects of UVR.

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Section: Introductionmentioning

confidence: 99%

A Quantitative Survey of Mycosporine-Like Amino Acids (MAAS) in Intertidal Egg Masses from Temperate Rocky Shores

2005

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“…The enzyme5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPs) (EC 2.5.1.19) is the sixth enzyme in the shikimate pathway, by which plants synthesize the aromatic amino acids phenylalanine, tyrosine, and tryptophan and other aromatic compounds used in secondary metabolism pathways in algae, plants, bacteria, and fungi (Kishore & Shah, 1988;Bentley, 1990). To put this into perspective, the shikimate pathway consumes about 20% of the total carbon fixed in photosynthesis by a plant (Herrmann & Weaver, 1999).…”

Section: Glyphosate Mode Of Actionmentioning

confidence: 99%

A Modified phosphate-carrier protein theory is proposed as a non-target site mechanism For glyphosate resistance in weeds

Roso

Vidal

2010

Planta daninha

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-Glyphosate is an herbicide that inhibits the enzyme 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPs) (EC 2.5.1.19). EPSPs is the sixth enzyme of the shikimate pathway, by which plants synthesize the aromatic amino acids phenylalanine, tyrosine, and tryptophan and many compounds used in secondary metabolism pathways. About fifteen years ago it was hypothesized that it was unlikely weeds would evolve resistance to this herbicide because of the limited degree of glyphosate metabolism observed in plants, the low resistance level attained to EPSPs gene overexpression, and because of the lower fitness in plants with an altered EPSPs enzyme. However, today 20 weed species have been described with glyphosate resistant biotypes that are found in all five continents of the world and exploit several different resistant mechanisms. The survival and adaptation of these glyphosate resistant weeds are related toresistance mechanisms that occur in plants selected through the intense selection pressure from repeated and exclusive use of glyphosate as the only control measure. In this paper the physiological, biochemical, and genetic basis of glyphosate resistance mechanisms in weed species are reviewed and a novel and innovative theory that integrates all the mechanisms of non-target site glyphosate resistance in plants is presented.Keywords: membrane carrier proteins, herbicide, weed resistance.RESUMO -Glyphosate é uma glicina fosfonada e inibe a enzima 5-enolpiruvil-shikimato-3-fosfato sintase (EPSPS) (EC 2.5.1.19). EPSPS é a sexta enzima da rota do shikimato, na qual são sintetizados os compostos do metabolismo secundário e os aminoácidos aromáticos fenilalanina, tirosina e triptofano. Alguns autores hipotetizaram que seria improvável a evolução de plantas daninhas resistentes a este herbicida. As justificativas estariam relacionadas à limitada metabolização de glyphosate nas plantas, ao baixo nível de resistência obtido com a superexpressão do gene EPSPS e à alta penalidade de adaptação oriunda de mutações no gene EPSPS. Mas, atualmente estão descritas 18 espécies com biótipos resistentes distribuídas em 17 países. A sobrevivência e adaptação estão relacionadas aos mecanismos de resistência que ocorrem nas plantas daninhas selecionadas em função da intensa pressão de seleção do herbicida. Esta revisão objetiva apresentar e discutir evidências fisiológicas, bioquímicas e genéticas que fundamentam os principais mecanismos envolvidos na resistência ao herbicida glyphosate em plantas daninhas.Palavras-chave: herbicida, proteínas carregadoras de membrana, planta daninha.

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“…MAAs are the product of a precursor in the shikimate pathway, branching off the main pathway at DHQ (Bentley, 1990). DHQ does not contain any nitrogen, but most MAAs have two nitrogenous groups.…”

Section: Approach and Expected Resultsmentioning

confidence: 99%

Methods and Models of Marine Optics Sources and Sinks

Mitchell¹

1997

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Public reporting burden for this collection of information is estimated to average one hour per response, including the time tor reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of Information, Including suggestions for reducing the burden to Washington Headquarters Services. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)Office of The goal of this project was to develop a solar simulating UV-visible incubator to grow HAB dinoflagellates, to begin MAA analysis of samples collected on global cruises, and to carry out initial experiments on HAB dinoflagellate species in pure culture. Our scientific objectives are to quantify MAA production and spectral induction mechanisms in HAB species, to characterize spectral absorption of MAAs, and to define the ecological benefit of MAAs (i.e. photoprotection). Data collected on cruises to the global oceans will be used to parameterize phytoplankton absorption in the UV region, and this parameterization could be incorporated into existing models of seawater optical properties in the UV spectral region. Data collected in this project were used for graduate fellowship applications by Elizabeth Frame. She has been awarded an EPA STAR fellowship to continue the work initiated by this project. SUBJECT TERMS AbstractThe development of an enhanced predictive and early warning capability for the occurrence and impact of harmful algal blooms (HABs) would be of great benefit to coastal communities. A critical issue for early detection and monitoring of HABs is the need to detect harmful algal species within a mixed-species phytoplankton assemblage. Possession of UV-absorbing compounds called mycosporine-like amino acids (MAAs) may be one factor that allows HAB species to out-compete their phytoplankton neighbors. Possession of MAAs, which we believe can be inferred from strong UVabsorption signals in phytoplankton absorption coefficients, can be used as a flag for potential HAB outbreak. The goal of this project was to develop a solar simulating UVvisible incubator to grow HAB dinoflagellates, to begin MAA analysis of samples collected on global cruises, and to carry out initial experiments on HAB dinoflagellate species in pure culture. Our scientific objectives are to quantify MAA production and spectral induction mechanisms in HAB species, to characterize spectral absorption of MAAs, and to define the ecological benefit of MAAs (i.e. photoprotection). Data collected on cruises to the global oceans will be used to parameterize phytoplankton absorption in the UV region, and this parameterization could be incorporated into existing models of seawater optical properties in the UV spectral region. Data collected in this project were used for graduate fellowship applications by Elizabeth Frame. She has been awarded an EPA STAR fellowship to continue the work initiated by this project.

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The Shikimate Pathway — A Metabolic Tree with Many Branche

Cited by 685 publications

References 483 publications

A Quantitative Survey of Mycosporine-Like Amino Acids (MAAS) in Intertidal Egg Masses from Temperate Rocky Shores

A Quantitative Survey of Mycosporine-Like Amino Acids (MAAS) in Intertidal Egg Masses from Temperate Rocky Shores

A Modified phosphate-carrier protein theory is proposed as a non-target site mechanism For glyphosate resistance in weeds

Methods and Models of Marine Optics Sources and Sinks

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