The oldest records of photosynthesis

Awramik, Stanley M.

doi:10.1007/bf00039172

Cited by 128 publications

(69 citation statements)

References 70 publications

(62 reference statements)

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“…It catalyzes the light-driven oxidation of water to molecular oxygen (1,2). The first organisms capable of this reaction were Gram-negative cyanobacteria that evolved 3.5 billion years ago (3).…”

Section: Photosystem II (Psii)mentioning

confidence: 99%

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

Grasse

Mamedov

Becker

et al. 2011

Journal of Biological Chemistry

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The multisubunit membrane protein complex Photosystem II (PSII) catalyzes one of the key reactions in photosynthesis: the light-driven oxidation of water. Here, we focus on the role of the Psb27 assembly factor, which is involved in biogenesis and repair after light-induced damage of the complex. We show that Psb27 is essential for the survival of cyanobacterial cells grown under stress conditions. The combination of cold stress (30°C) and high light stress (1000 mol of photons ؋ m ؊2 ؋ s ؊1 ) led to complete inhibition of growth in a ⌬psb27 mutant strain of the thermophilic cyanobacterium Thermosynechococcus elongatus, whereas wild-type cells continued to grow. Moreover, Psb27-containing PSII complexes became the predominant PSII species in preparations from wild-type cells grown under cold stress. Two different PSII-Psb27 complexes were isolated and characterized in this study. The first complex represents the known monomeric PSII-Psb27 species, which is involved in the assembly of PSII. Additionally, a novel dimeric PSII-Psb27 complex could be allocated in the repair cycle, i.e. in processes after inactivation of PSII, by 15 N pulse-label experiments followed by mass spectrometry analysis. Comparison with the corresponding PSII species from ⌬psb27 mutant cells showed that Psb27 prevented the release of manganese from the previously inactivated complex. These results indicate a more complex role of the Psb27 protein within the life cycle of PSII, especially under stress conditions. Photosystem II (PSII)2 is the first component of the photosynthetic electron transfer chain located in the thylakoid membranes of cyanobacteria and plant chloroplasts. It catalyzes the light-driven oxidation of water to molecular oxygen (1, 2). The first organisms capable of this reaction were Gram-negative cyanobacteria that evolved 3.5 billion years ago (3).Active cyanobacterial PSII consists of 20 permanent subunits, which were identified in the x-ray structure of PSII complexes isolated from Thermosynechococcus elongatus BP-1 (henceforth T. elongatus) (4). The central D1 and D2 subunits ligate multiple cofactors that facilitate the water-splitting reaction and mediate the electron transfer to plastoquinone B (Q B ). The central antenna proteins CP43 and CP47 capture the light energy, which in turn excites the Chl D1 molecule of P680. This causes a charge separation at the primary donor with the electron subsequently transferred to pheophytin (5). After Chl D1 ϩ is reduced by P D1 , the electron is transferred from pheophytin to Q A and Q B , respectively. In turn, P D1 ϩ is rereduced by electrons from the CaMn 4 cluster and the water-splitting reaction.During the early steps of biogenesis that probably takes place in the cytoplasmic membrane (6) a PSII precomplex is formed consisting of the central heterodimer D1 and D2, cytochrome b 559 , and PsbI (7-9). This precomplex is the smallest known unit capable of charge separation. Before a functional manganese cluster can be assembled, the D1 protein that is expressed as a precursor...

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Section: Photosystem II (Psii)mentioning

confidence: 99%

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

Grasse

Mamedov

Becker

et al. 2011

Journal of Biological Chemistry

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“…These are microscopic, subdivided carbonaceous structures that resemble cellular prokaryotic microfossils owing to the presence of cell-like septation (figure 2h). They have been reported from several localities in the early Archaean of Western Australia (table 1) where they have been interpreted as the remains of bacteria (figure 3h), and at times compared with photosynthetic cyanobacteria because of their size range (Awramik et al 1983;Schopf & Packer 1987;Awramik 1992;Schopf 1992aSchopf , 1993Schopf , 1999Ueno et al 2001). The formation of cell-like structures from crystal growth, however, has long been known (Baker & Harris 1978;Horodyski 1981 the famous early Archaean, Apex Chert examples are associated with the recrystallization of amorphous glassy silica to spherulitic chalcedony and other hydrothermal fabrics (see below).…”

Section: Candidate Morphotypesmentioning

confidence: 99%

A fresh look at the fossil evidence for early Archaean cellular life

Brasier

McLoughlin

Green

et al. 2006

Phil. Trans. R. Soc. B

257

154

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The rock record provides us with unique evidence for testing models as to when and where cellular life first appeared on Earth. Its study, however, requires caution. The biogenicity of stromatolites and 'microfossils' older than 3.0 Gyr should not be accepted without critical analysis of morphospace and context, using multiple modern techniques, plus rejection of alternative non-biological (null) hypotheses. The previous view that the co-occurrence of biology-like morphology and carbonaceous chemistry in ancient, microfossil-like objects is a presumptive indicator of biogenicity is not enough. As with the famous Martian microfossils, we need to ask not 'what do these structures remind us of ?', but 'what are these structures?' Earth's oldest putative 'microfossil' assemblages within 3.4-3.5 Gyr carbonaceous cherts, such as the Apex Chert, are likewise self-organizing structures that do not pass tests for biogenicity.There is a preservational paradox in the fossil record prior to ca 2.7 Gyr: suitable rocks (e.g. isotopically light carbonaceous cherts) are widely present, but signals of life are enigmatic and hard to decipher. One new approach includes detailed mapping of well-preserved sandstone grains in the ca 3.4 Gyr Strelley Pool Chert. These can contain endolithic microtubes showing syngenicity, grain selectivity and several levels of geochemical processing. Preliminary studies invite comparison with a class of ambient inclusion trails of putative microbial origin and with the activities of modern anaerobic proteobacteria and volcanic glass euendoliths.

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“…Ello apoya la idea de que las zonas costeras estuarinas fueron muy productivas en aquel tiempo, y que la fotosíntesis ya estaba operando (Awramik, 1992;Rosing y Frei, 2004;Tice y Lowe, 2004;Buick, 2008;Hoashi et al, 2009;Kato et al, 2009;Kendall et al, 2010), aunque tal vez no necesariamente oxigénica (Westall et al, 2011;Li et al, 2012).…”

Section: El Escenario De La Vida Tempranaunclassified

La vida temprana en la Tierra y los primeros ecosistemas terrestres

Beraldi-Campesi¹

2014

BSGM

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La vida temprana en la Tierra y los primeros ecosistemas terrestres 65 ResumenLos ecosistemas terrestres han sido considerados tradicionalmente como superficies dominadas por plantas, cuyos primeros registros datan del Fanerozoico temprano (< 550 Ma/millones de años). Sin embargo, la presencia de componentes biológicos mucho más antiguos que las plantas en hábitats tan distintos como suelos, turberas, estanques, lagos, arroyos y dunas, sugiere que los ecosistemas terrestres comenzaron a existir en la Tierra hace al menos 2700 Ma. Los microbios fueron abundantes hace ~3500 Ma y sin duda se adaptaron a vivir en condiciones subaéreas, en entornos intermareales y en zonas áridas y semiáridas, como lo hacen actualmente los microbios terrestres, y que tienen una enorme y rápida capacidad de adaptación a condiciones cambiantes. Todo ello está respaldado por el registro fósil. No obstante, esta evidencia es inusual e indirecta en comparación con fósiles de ambientes marinos, superficiales o profundos, y su registro ha sido poco atendido. En consecuencia, la noción de que fueron comunidades microbianas las que formaron los primeros ecosistemas terrestres no ha sido ampliamente difundido ni incorporado conceptualmente en la sociedad. Hoy conocemos un amplio registro fósil de biota marina somera y lacustre a partir de los ~3500 Ma, así como microbios colonizando ambientes costeros desde hace ~3450 Ma y evidencia indirecta de actividad biológica en paleosuelos de > 3400 Ma de edad. El tipo de ambientes, de donde proviene esta evidencia, sugiere que la vida terrestre se produjo casi en paralelo con la vida acuática en el Arqueano. Las rápidas adaptaciones observadas en microbios actuales, su excepcional tolerancia a condiciones extremas y fluctuantes, su rápida y temprana diversificación y su antiguo registro fósil, indican que los primeros ecosistemas terrestres fueron exclusivamente microbianos. Es factible que los microbios contribuyeran en la formación de los primeros suelos donde las plantas se desarrollaron más tarde. Comprender cómo la vida se diversificó y adaptó a las condiciones terrestres es fundamental para entender su impacto en los sistemas terrestres durante millones de años. Beraldi-Campesi 66 661. Introducción Definición de terrestreLos ambientes terrestres seguramente han existido a través de toda la historia geológica de la Tierra a menos que su superficie estuviera permanentemente bajo el agua, lo cual no es aceptablemente realista. La definición de 'terrestre' no es tan trivial como parece. Aunque aquí se define como un ambiente 'no acuático', la distinción entre lo marino y lo terrestre atraviesa un amplio espectro de ambientes transicionales, donde lo acuático y lo no-acuático evolucionan y superponen en el tiempo. Comúnmente se entiende que un entorno terrestre (sobre el nivel del mar), puede incluir ambientes acuáticos (lagos cubiertos o no de hielo, lagunas y humedales, turberas, ríos y arroyos, campos geotérmicos) y no-acuáticos (especialmente zonas con poca lluvia). Estos hábitats pueden experimen...

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The oldest records of photosynthesis

Cited by 128 publications

References 70 publications

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

A fresh look at the fossil evidence for early Archaean cellular life

La vida temprana en la Tierra y los primeros ecosistemas terrestres

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