Lignin: Occurrence, Biogenesis and Biodegradation

Lewis, Norman; Yamamoto, Etsuji

doi:10.1146/annurev.pp.41.060190.002323

Cited by 910 publications

(526 citation statements)

References 74 publications

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“…Aphenoxy radical coupling mechanism has been proposed for the polymerization of monolignols to form lignins or for their dimerization to form lignans (Lewis & Yamamoto, 1990). Laccases and peroxidases have been considered to be responsible for generation of monolignol radicals which are prerequisites for the proposed coupling mechanism O'Malley et al, 1993).…”

Section: Stellacyanin Plastocyaninmentioning

confidence: 99%

Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins: Plant‐specific mononuclear blue copper proteins

et al. 1998

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The cDNAs encoding plantacyanin from spinach were isolated and characterized. In addition, four new cDNA sequences from Arubidopsis ESTs were identified that encode polypeptides resembling phytocyanins, plant-specific proteins constituting a distinct family of mononuclear blue copper proteins. One of them encodes plantacyanin from Arubidopsis. while three others, designated as uclacyanin 1, 2, and 3, encode protein precursors that are closely related to precursors of stellacyanins and a blue copper protein from pea pods. Comparative analyses with known phytocyanins allow further classification of these proteins into three distinct subfamilies designated as uclacyanins, stellacyanins, and plantacyanins. This specification is based on (1) their spectroscopic properties, (2) their glycosylation state, (3) the domain organization of their precursors, and (4) their copper-binding amino acids. The recombinant copper binding domain of Arubidopsis uclacyanin I was expressed, purified, and shown to bind a copper atom in a fashion known as "blue" or type 1. The mutant of cucumber stellacyanin in which the glutamine axial ligand was substituted by a methionine (Q99M) was purified and shown to possess spectroscopic properties similar to uclacyanin I rather than to plantacyanins. Its redox potential was determined by cyclic voltammetry to be +420 mV, a value that is significantly higher than that determined for the wild-type protein (+260 mV). The available structural data suggest that stellacyanins (and possibly other phytocyanins) might not be diffusible electron-transfer proteins participating in long-range electron-transfer processes. Conceivably, they are involved in redox reactions occurring during primary defense responses in plants and/or in lignin formation.

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Section: Stellacyanin Plastocyaninmentioning

confidence: 99%

Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins: Plant‐specific mononuclear blue copper proteins

et al. 1998

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“…Substâncias impermeáveis à água tais como ceras, suberina, tanino ou lignina podem ser encontrados na parede celular (McDougall et al, 1996). A lignina é um polímero natural e está presente apenas na testa (Lewis e Yamamoto, 1990). Tavares et al (1987) verificaram que os maiores valores de lignina encontravam-se nas linhagens de soja com testa impermeável.…”

Section: Introductionunclassified

Influência do envelhecimento acelerado na anatomia da testa de sementes de soja, cv. Monsoy 8400

Silva¹,

Vieira

Santos

2008

Rev. bras. sementes

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Durante o processo de envelhecimento, as sementes sofrem alterações degenerativas que influenciam o seu potencial fisiológico. Entre estas alterações podem estar as modificações anatômicas nas camadas celulares da testa da semente. Objetivou-se, com este trabalho, verificar a relação entre a anatomia da testa de sementes de soja, cultivar Monsoy 8400 e a germinação, após o envelhecimento acelerado, pelo fato da testa apresentar um papel fundamental na conservação do potencial fisiológico das sementes. As sementes foram envelhecidas a 42ºC e 100% UR do ar por períodos de zero, 24, 48, 72 e 96 horas. Avaliaram-se os teores de água e a germinação, posteriormente à secagem, seções transversais da testa de 10 sementes de cada tratamento foram eletromicrografadas, com microscópio eletrônico de varredura,,observando-se as camadas das células paliçádicas, ampulhetas e parenquimáticas A germinação declinou com o aumento dos períodos de envelhecimento. Houve redução da espessura das camadas da testa nos períodos de 48, 72 e 96 horas deste processo. Observou-se que, principalmente, para os períodos de envelhecimento de 72 e 96 horas, que as células da camada hipodérmica apresentaram um aspecto de colapso, sendo este acentuado para o período de 96 horas. A redução da espessura das camadas sugere a ocorrência de um colapso das células que compõem tais camadas, sendo um fator causador da redução do potencial germinativo.

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“…More importantly, from a stable carbon isotope viewpoint, the basic molecular composition of the solvent insoluble component, i.e., ligno-cellulose which constitutes the bulk of wood, is well-known. Ligno-cellulose is composed of polysaccharides, hemicellulose and cellulose, and lignin (Sarkanen and Ludwig, 1971;Lewis and Yamamoto, 1990). The composition of lignin varies according to major plant taxa; gymnosperm lignin is comprised of 2-methoxyphenol moieties (guaiacyl units) whilst angiosperm lignin also contains 2,6-dimethoxyphenol moieties (syringyl units) (Sarkanen and Ludwig, 1971;Lewis and Yamamoto, 1990).…”

Section: Introductionmentioning

confidence: 99%

Stable carbon isotopes of wood: a clue to palaeoclimate?

Bergen

Poole

2002

Palaeogeography, Palaeoclimatology, Palaeoecology

104

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Detailed stable carbon isotope and molecular investigations were undertaken on a number of archaeological and fossil wood specimens to provide insights into their use as rigorous independent palaeoclimatic and palaeoenvironmental parameters. The isotope data revealed large differences amongst the material with the oldest specimens being least depleted in 13 C. Although natural variation could account for some of the observed differences, the isotope values of the archaeological and Tertiary specimens are most probably related to the absolute abundance of polysaccharides present and the degree of lignin alteration. The molecular data, based on pyrolysis, of the Antarctic Cretaceous conifer specimens revealed only transformed lignin, with virtually no intact lignin building blocks (2-methoxyphenols) preserved, and no evidence of polysaccharides. This degree of chemical alteration is suggested here to be one of the main causes for the 13 C enriched values of these conifer specimens. These results show the importance of combining detailed molecular information on individual wood components with stable carbon isotope data for palaeoclimatic and palaeoenvironmental studies. ß

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Lignin: Occurrence, Biogenesis and Biodegradation

Cited by 910 publications

References 74 publications

Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins: Plant‐specific mononuclear blue copper proteins

Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins: Plant‐specific mononuclear blue copper proteins

Influência do envelhecimento acelerado na anatomia da testa de sementes de soja, cv. Monsoy 8400

Stable carbon isotopes of wood: a clue to palaeoclimate?

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