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1.
J Plant Res ; 132(5): 601-616, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31446516

RESUMO

The Chinese occurrences of the marattioid fern genus Christensenia have been considered as requiring protection because of its extreme rarity and very small population size. Here, we explored different biological aspects to enable protection of these rare ferns, well known as Mesozoic living fossils. Firstly, we documented the cytology of the Chinese occurrences for the first time. This is the second tetraploid record of Christensenia worth for further studies to confirm its taxonomic status. Secondly, we obtained the first complete plastid genome of this genus, which confirmed the proposed conservatism of the plastid genome structure in marattioid ferns. By comparing the chloroplast genome with other marattioids, we identified several candidate regions to develop highly variable markers to investigate the intra-species diversity of marattioid ferns. Thirdly, phylogenetic analyses of rbcL sequences implied that there are at least two distinct species of Christensenia. Finally, we re-assessed the conservation status of Christensenia in the context of its local and global distribution by assessing specimen information extracted from publications and digitized voucher information. This assessment confirmed the need to obtain more accurate information about the distribution of this genus to assess the status incorporating the disjunct distribution from southern China and India in the North towards the Solomon Islands in the South.


Assuntos
Conservação dos Recursos Naturais , Gleiquênias/genética , Genoma de Cloroplastos , Dispersão Vegetal , China , Gleiquênias/classificação , Gleiquênias/citologia , Filogenia , Ribulose-Bifosfato Carboxilase/análise , Análise de Sequência de DNA
2.
Biochem Biophys Res Commun ; 505(4): 1050-1056, 2018 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-30314694

RESUMO

Rubisco, an enzyme for photosynthetic carbon dioxide fixation, is a major green leaf protein and known as the most abundant protein on the Earth. We found that Rubisco digested mimicking gastrointestinal enzymatic conditions exhibited anxiolytic-like effects after oral administration in mice. Based on a comprehensive peptide analysis of the digest using nanoLC-Orbitrap-MS and the structure-activity relationship of known anxiolytic-like peptides, we identified SYLPPLTT, SYLPPLT and YHIEPV [termed Rubisco anxiolytic-like peptide (rALP)-1, rALP-1(1-7) and rALP-2, respectively], which exhibited potent anxiolytic-like effects after oral administration. The anxiolytic-like effects of rALP-1/rALP-1(1-7) were blocked by a serotonin 5-HT1A receptor antagonist, whereas rALP-2-induced effects were inhibited by a δ-opioid receptor antagonist. In conclusion, novel Rubisco-derived anxiolytic-like peptides, rALP-1/rALP-1(1-7) and rALP-2, act via independent neural pathways.


Assuntos
Ansiolíticos/análise , Peptídeos/análise , Folhas de Planta/metabolismo , Proteínas de Plantas/análise , Ribulose-Bifosfato Carboxilase/análise , Spinacia oleracea/metabolismo , Administração Oral , Animais , Ansiolíticos/metabolismo , Ansiolíticos/farmacologia , Ansiedade/tratamento farmacológico , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos , Peptídeos/metabolismo , Peptídeos/farmacologia , Folhas de Planta/química , Proteínas de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Spinacia oleracea/química
3.
Nat Plants ; 4(10): 802-810, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30287949

RESUMO

Rubisco catalyses a rate-limiting step in photosynthesis and has long been a target for improvement due to its slow turnover rate. An alternative to modifying catalytic properties of Rubisco is to increase its abundance within C4 plant chloroplasts, which might increase activity and confer a higher carbon assimilation rate. Here, we overexpress the Rubisco large (LS) and small (SS) subunits with the Rubisco assembly chaperone RUBISCO ASSEMBLY FACTOR 1 (RAF1). While overexpression of LS and/or SS had no discernable impact on Rubisco content, addition of RAF1 overexpression resulted in a >30% increase in Rubisco content. Gas exchange showed a 15% increase in CO2 assimilation (ASAT) in UBI-LSSS-RAF1 transgenic plants, which correlated with increased fresh weight and in vitro Vcmax calculations. The divergence of Rubisco content and assimilation could be accounted for by the Rubisco activation state, which decreased up to 23%, suggesting that Rubisco activase may be limiting Vcmax, and impinging on the realization of photosynthetic potential from increased Rubisco content.


Assuntos
Proteínas de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Zea mays/metabolismo , Cloroplastos/metabolismo , Immunoblotting , Chaperonas Moleculares/metabolismo , Fotossíntese , Plantas Geneticamente Modificadas , Ribulose-Bifosfato Carboxilase/análise , Zea mays/química
4.
J Phycol ; 54(6): 811-817, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30137670

RESUMO

Light/scanning electron/transmission microscopy-based morphological analyses and multiple nucleotide sequences-based molecular phylogenetic analyses are used to identify and assess the phylogenetic position of a new unidentified green alga isolated from bleached corals living in the South China Sea. This new unidentified green alga is a unicellular marine alga and has uninucleate vegetative cells and multiple chloroplasts with a pyrenoid. It can form aplanosporangium covered by cell walls and reproduces by releasing autospore. These features differ substantially from those of the two genera Ignatius and Pseudocharacium. Those two genera have been accommodated in the Ignatius clade. Nucleotide sequences of the nuclear small subunit ribosomal RNA gene (18S rRNA), internal transcribed spacer 2 of ribosomal RNA gene (ITS2) and ribulose-1,5 bisphosphate carboxylase/oxygenase large subunit gene (rbcL, partial) are obtained and compared with published green algal sequences. The results from the morphology, ultrastructure, and multiple nucleotide sequences data support the placement of the new unidentified green alga in Ulvophyceae. This new unidentified isolate is described as Symbiochlorum hainanensis gen. et sp. nov., a new sister lineage to the Ignatius clade, Ulvophyceae, Chlorophyta.


Assuntos
Clorófitas/classificação , Microalgas/classificação , Filogenia , RNA de Algas/análise , Animais , Antozoários , China , Clorófitas/citologia , Clorófitas/enzimologia , Clorófitas/genética , DNA Espaçador Ribossômico/análise , Microalgas/citologia , Microalgas/enzimologia , Microalgas/genética , Oceano Pacífico , RNA Ribossômico 18S/análise , Ribulose-Bifosfato Carboxilase/análise , Simbiose
5.
J Phycol ; 54(4): 557-570, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29908074

RESUMO

Some diatoms are able to colonize as epibionts on their potential zooplankton predators. Here, we report Pseudohimantidium pacificum living on the copepod Corycaeus giesbrechti and as a new finding on Oithona nana, Protoraphis atlantica living on the copepod Pontellopsis brevis, Protoraphis hustedtiana on the cypris larvae of barnacles, and Falcula hyalina on the copepod Acartia lilljeborgii. The epizoic diatoms were able to grow as free-living forms under culture conditions. Pseudohimantidium pacificum and P. atlantica appeared as the most derived species from their benthic diatom ancestors. The mucilage pad or stalk of the strains of these species showed important morphological distinction when compared with their epizoic forms. Barnacle larvae explore benthic habitats before settlement, and epibiosis on them is an example where P. hustedtiana profits from the host behavior for dispersal of its benthic populations. Molecular phylogenies based on the SSU rRNA and RuBisCO large subunit (rbcL) gene sequences revealed F. hyalina as an independent lineage within the Fragilariales (Tabularia, Catacombas, and others), consistent with its morphological distinction in the low number of rows (≤6) in the ocellulimbus, among other features. We propose the transfer of F. hyalina to the genus Pseudofalcula gen. nov. Molecular phylogeny suggests a single order for the members of the Cyclophorales and the Protoraphidales, and that the epibioses of araphid diatoms on marine zooplankton have been independently acquired several times. These clades are constituted of both epizoic and epiphytic/epilithic forms that evidence a recent acquisition of the epizoic modus vivendi.


Assuntos
Diatomáceas/classificação , Zooplâncton/classificação , Animais , DNA Ribossômico/análise , Diatomáceas/citologia , Diatomáceas/genética , Diatomáceas/ultraestrutura , Microscopia Eletrônica de Varredura , Filogenia , Fitoplâncton/classificação , Fitoplâncton/citologia , Fitoplâncton/genética , Fitoplâncton/ultraestrutura , Ribulose-Bifosfato Carboxilase/análise , Zooplâncton/citologia , Zooplâncton/genética , Zooplâncton/ultraestrutura
6.
J Environ Manage ; 218: 71-78, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29665488

RESUMO

The aim of the study was to evaluate sensitivity and potential applications of selected biomarkers in phytoremediation under complex heavy metal contamination in Sinapis alba L., Robinia pseudoacacia L. and Lupinus luteus L as a potential tools in effective phytoremediation management. The toxicity assessment was conducted using selected measurement endpoints, both classical and advanced, i.e., germination index, roots length, guaiacol peroxidase activity (GPX), chlorophyll and protein content, the amount of total phenolic compounds (TPC) and level of expression of one of the ribulose-bisphosphate carboxylase genes (rbcL). Moreover, the influence of organic additives: cattle, horse manure, and vermicompost on lowering plant abiotic stress caused by complex heavy metal contamination was studied to assess the possible applications of selected stress markers in large scale phytoremediation planning. The results demonstrated the beneficial effects of selected soil additives on plant development. The 5% difference in the quantity of applied amendment caused statistically significant differences in GPX, TPC, chlorophyll content and expression level of rbcL. Among all endpoints, GPX activity, chlorophyll, and phenolic compounds content, as well as the expression of rbcL, turned out to be the most reliable assays for determination of the type and dosage of selected soil amendments (fertilizers) in the assisted phytoremediation process. Selected markers can be used to achieve the desired level of plant abiotic stress and consequently photosynthesis efficiency and CO2 sequestration. The results showed, that presented assays can be used in different taxonomical groups such as Fabaceae for planning effective phytoremediation process.


Assuntos
Metais Pesados , Plantas/genética , Ribulose-Bifosfato Carboxilase/análise , Poluentes do Solo , Animais , Antioxidantes , Biodegradação Ambiental , Bovinos , Cavalos , Solo
7.
PLoS One ; 11(12): e0167802, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27936133

RESUMO

PolyGly is present in many proteins in various organisms. One example is found in a transmembrane ß-barrel protein, translocon at the outer-envelope-membrane of chloroplasts 75 (Toc75). Toc75 requires its N-terminal extension (t75) for proper localization. t75 comprises signals for chloroplast import (n75) and envelope sorting (c75) in tandem. n75 and c75 are removed by stromal processing peptidase and plastidic type I signal peptidase 1, respectively. PolyGly is present within c75 and its deletion or substitution causes mistargeting of Toc75 to the stroma. Here we have examined the properties of polyGly-dependent protein targeting using two soluble passenger proteins, the mature portion of the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (mSS) and enhanced green fluorescent protein (EGFP). Both t75-mSS and t75-EGFP were imported into isolated chloroplasts and their n75 removed. Resultant c75-mSS was associated with the envelope at the intermembrane space, whereas c75-EGFP was partially exposed outside the envelope. Deletion of polyGly or substitution of tri-Ala for the critical tri-Gly segment within polyGly caused each passenger to be targeted to the stroma. Transient expression of t75-EGFP in Nicotiana benthamiana resulted in accumulation of c75-EGFP exposed at the surface of the chloroplast, but the majority of the EGFP passenger was found free in the cytosol with most of its c75 attachment removed. Results of circular dichroism analyses suggest that polyGly within c75 may form an extended conformation, which is disrupted by tri-Ala substitution. These data suggest that polyGly is distinct from a canonical stop-transfer sequence and acts as a rejection signal at the chloroplast inner envelope.


Assuntos
Cloroplastos/metabolismo , Ervilhas/metabolismo , Peptídeos/metabolismo , Proteínas de Plantas/metabolismo , Cloroplastos/química , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Membrana/análise , Proteínas de Membrana/metabolismo , Ervilhas/química , Peptídeos/análise , Proteínas de Plantas/análise , Transporte Proteico , Ribulose-Bifosfato Carboxilase/análise , Ribulose-Bifosfato Carboxilase/metabolismo
8.
Tree Physiol ; 36(10): 1296-1306, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27614357

RESUMO

The presence of anthocyanins in young leaves plays an important role in mitigation against photodamage and allows leaves to grow and develop normally. Many studies have reported that foliar anthocyanins are distributed within the vacuoles of mesophyll cells, so we explored the novel defence style of anthocyanin-coated young leaves of Castanopsis fissa, a dominant subtropical forest tree species, via removable trichomes. Anthocyanins were distributed in C. fissa leaf trichomes, which produced a red coating for the young leaves. As young leaves developed and then matured, the thickness and density of the anthocyanin trichomes progressively decreased, the coating finally disappearing, allowing greater utilization of light by mature leaves. In addition to anthocyanins, the trichomes contained a remarkably high amount of phenolics, which enable the red coating to be more efficient in screening ultraviolet light. Compared with mature leaves, the young leaves exhibited lower photosynthetic ability, which was attributable to the reduced chlorophyll and Rubisco contents. Removal of the red coating had little effect on the photosynthetic capacity of young leaves. However, the young leaves without the coating suffered greater light-induced photoinhibition due to greater excess light entering the chloroplast and the production of H2O2 Our results suggest that the anthocyanin coating is photoprotective and this anthocyanin defence style may be a metabolically cost-effective way of adjusting the anthocyanin content in response to demand.


Assuntos
Antocianinas/fisiologia , Fagaceae/fisiologia , Folhas de Planta/fisiologia , Árvores/fisiologia , Tricomas/fisiologia , Clorofila/metabolismo , Fagaceae/efeitos da radiação , Florestas , Fotossíntese , Folhas de Planta/química , Folhas de Planta/efeitos da radiação , Ribulose-Bifosfato Carboxilase/análise , Luz Solar , Árvores/efeitos da radiação , Tricomas/efeitos da radiação
9.
Food Chem ; 203: 402-408, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26948631

RESUMO

Plant leaves are a major potential source of novel food proteins. Till now, leaf protein extraction methods mainly focus on the extraction of soluble proteins, like rubisco protein, leaving more than half of all protein unextracted. Here, we report on the total protein extraction from sugar beet leaves (Beta vulgaris L.) by a traditional thermal extraction method consisting of mechanical pressing, heating to 50 °C and centrifugation. The resulting streams (i.e. supernatant, green-protein pellet and fibrous pulp) were characterised in terms of composition, physical structure and processing options. The protein distributed almost equally over the supernatant, pellet and pulp. This shows that thermal precipitation is an unselective process with respect to fractionation between soluble (rubisco) and insoluble (other) proteins. About 6% of the total protein could be extracted as pure rubisco (90% purity) from the supernatant. Surfactants commonly used for protein solubilisation could hardly re-dissolve the precipitated proteins in the pellet phase, which suggested that irreversible association was induced between the co-precipitated proteins and cell debris. Thus, the extraction of this protein will require prevention of their co-precipitation, and should take place in the original juice solution.


Assuntos
Beta vulgaris/química , Fibras na Dieta/análise , Folhas de Planta/química , Proteínas de Vegetais Comestíveis/análise , Ribulose-Bifosfato Carboxilase/análise , Fracionamento Químico , Solubilidade
10.
Ying Yong Sheng Tai Xue Bao ; 26(3): 847-52, 2015 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-26211068

RESUMO

This study investigated the effects of exogenous 24-epibrassinolide (EBR) on the leaf morphology and photosynthetic characteristics of tomato seedlings (cv. Jiersi) cultured hydroponically under low light stress. The results showed that low light stress induced adaptive changes in the leaf morphology of tomato seedling. Low light stress significantly increased the leaf area, specific leaf area, angle between stem and leaf, vertical angle and cable bent, but significantly decreased the dry mass of leaf. Low light stress also significantly decreased the maximum net photosynthetic rate,. apparent quantum yield, dark respiration rate, carboxylation efficiency and Rubisco large subunit content. The light compensation point and carbon dioxide compensation point were dramatically enhanced under low light stress. However, foliar spraying EBR significantly increased the leaf area, leaf dry mass, angle between stem and leaf, vertical angle by 14.1%, 57.1%, 12.3% and 7.7% under low light stress, respectively. EBR significantly decreased the specific leaf area and cable bent by 30.5% and 10.6% in low light stressed plants. In addition, EBR significantly enhanced the apparent quantum yield, dark respiration rate and carboxylation efficiency by 20.4%, 17.9% and 9.3%, respectively, but significantly reduced the light compensation point and carbon dioxide compensation point by 21.9% and 4.3% under low light stress. Moreover, EBR also significantly increased the Rubisco large subunit content in low light stressed leaves. These results suggested that application of exogenous EBR could effectively alleviate the inhibition of photosynthesis induced by low light stress via improving the apparent quantum yield, dark respiration rate, carboxylation efficiency and Rubisco content, and maintaining the stability of leaf morphology, thus low light tolerance of tomato seedlings.


Assuntos
Brassinosteroides/farmacologia , Luz , Lycopersicon esculentum/fisiologia , Fotossíntese/efeitos dos fármacos , Folhas de Planta/fisiologia , Esteroides Heterocíclicos/farmacologia , Adaptação Fisiológica , Dióxido de Carbono/análise , Lycopersicon esculentum/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Ribulose-Bifosfato Carboxilase/análise , Plântula/fisiologia , Estresse Fisiológico
11.
Tree Physiol ; 35(1): 47-60, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25576757

RESUMO

The present work has explored for the first time acclimation of upper versus lower canopy leaves along an altitudinal gradient. We tested the hypothesis that restrictive climatic conditions associated with high altitudes reduce within-canopy variations of leaf traits. The investigated beech (Fagus sylvatica L.) forest is located on the southern slope of the Hrubý Jeseník Mountains (Czech Republic). All measurements were taken on leaves from upper and lower parts of the canopy of mature trees (>85 years old) growing at low (400 m above sea level, a.s.l.), middle (720 m a.s.l.) and high (1100 m a.s.l.) altitudes. Compared with trees at higher altitudes, those growing at low altitudes had lower stomatal conductance, slightly lower CO(2) assimilation rate (A(max)) and leaf mass per area (LMA), and higher photochemical reflectance index, water-use efficiency and Rubisco content. Given similar stand densities at all altitudes, the different growth conditions result in a more open canopy and higher penetration of light into lower canopy with increasing altitude. Even though strong vertical gradients in light intensity occurred across the canopy at all altitudes, lower canopy leaves at high altitudes tended to acquire the same morphological, biochemical and physiological traits as did upper leaves. While elevation had no significant effect on nitrogen (N) and carbon (C) contents per unit leaf area, LMA, or total content of chlorophylls and epidermal flavonoids in upper leaves, these increased significantly in lower leaves at higher altitudes. The increases in N content of lower leaves were coupled with similar changes in A(max). Moreover, a high N content coincided with high Rubisco concentrations in lower but not in upper canopy leaves. Our results show that the limiting role of light in lower parts of the canopy is reduced at high altitudes. A great capacity of trees to adjust the entire canopy is thus demonstrated.


Assuntos
Altitude , Fagus/fisiologia , Fenótipo , Fotossíntese , Folhas de Planta/fisiologia , Estômatos de Plantas/fisiologia , Carbono/análise , Dióxido de Carbono/metabolismo , Fagus/anatomia & histologia , Fagus/genética , Luz , Nitrogênio/análise , Folhas de Planta/anatomia & histologia , Folhas de Planta/química , Estômatos de Plantas/anatomia & histologia , Ribulose-Bifosfato Carboxilase/análise , Água/metabolismo
12.
Appl Environ Microbiol ; 80(21): 6750-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25172848

RESUMO

Understanding the interconnectivity of oceanic carbon and nitrogen cycles, specifically carbon and nitrogen fixation, is essential in elucidating the fate and distribution of carbon in the ocean. Traditional techniques measure either organism abundance or biochemical rates. As such, measurements are performed on separate samples and on different time scales. Here, we developed a method to simultaneously quantify organisms while estimating rates of fixation across time and space for both carbon and nitrogen. Tyramide signal amplification fluorescence in situ hybridization (TSA-FISH) of mRNA for functionally specific oligonucleotide probes for rbcL (ribulose-1,5-bisphosphate carboxylase/oxygenase; carbon fixation) and nifH (nitrogenase; nitrogen fixation) was combined with flow cytometry to measure abundance and estimate activity. Cultured samples representing a diversity of phytoplankton (cyanobacteria, coccolithophores, chlorophytes, diatoms, and dinoflagellates), as well as environmental samples from the open ocean (Gulf of Mexico, USA, and southeastern Indian Ocean, Australia) and an estuary (Galveston Bay, Texas, USA), were successfully hybridized. Strong correlations between positively tagged community abundance and (14)C/(15)N measurements are presented. We propose that these methods can be used to estimate carbon and nitrogen fixation in environmental communities. The utilization of mRNA TSA-FISH to detect multiple active microbial functions within the same sample will offer increased understanding of important biogeochemical cycles in the ocean.


Assuntos
Ciclo do Carbono , Microbiologia Ambiental , Citometria de Fluxo/métodos , Hibridização In Situ/métodos , Fixação de Nitrogênio , Oxirredutases/análise , Ribulose-Bifosfato Carboxilase/análise , Nitrogênio/metabolismo , Oxirredutases/genética , Ribulose-Bifosfato Carboxilase/genética
13.
FEMS Microbiol Ecol ; 81(2): 480-93, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22458451

RESUMO

Endosymbionts in marine bivalves leave characteristic biosignatures in their host organisms. Two nonseep bivalve species collected in Mediterranean lagoons, thiotrophic symbiotic Loripes lacteus and filter-feeding nonsymbiotic Venerupis aurea, were studied in detail with respect to generation and presence of such signatures in living animals, and the preservation of these signals in subfossil (late Pleistocene) sedimentary shells. Three key enzymes from sulfur oxidation (APS-reductase), CO(2) fixation (RubisCO) and assimilation of nitrogen [glutamine synthetase (GS)] were detected by immunofluorescence in the bacterial symbionts of Loripes. In Loripes, major activity was derived from GS of the symbionts whereas in Venerupis the host GS is active. In search of geologically stable biosignatures for thiotrophic chemosymbiosis that might be suitable to detect such associations in ancient bivalves, we analyzed the isotopic composition of shell lipids (δ(13)C) and the bulk organic matrix of the shell (δ(13)C , δ(15)N , δ(34)S). In the thiotrophic Loripes, δ(13)C values were depleted compared with the filter-feeding Venerupis by as much as 8.5‰ for individual fatty acids, and 4.4‰ for bulk organic carbon. Likewise, bulk δ(15)N and δ(34)S values were more depleted in recent thiotrophic Loripes. Whereas δ (34)S values were found to be unstable over time, the combined δ(15)N and δ(13)C values in organic shell extracts revealed a specific signature for chemosymbiosis in recent and subfossil specimens.


Assuntos
Exoesqueleto/química , Bactérias/enzimologia , Bivalves/microbiologia , Isótopos de Carbono/análise , Simbiose , Animais , Bactérias/genética , Bivalves/química , Ciclo do Carbono , Fósseis , Glutamato-Amônia Ligase/análise , Nitrogênio/química , Isótopos de Nitrogênio/análise , Oxirredução , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/análise , RNA Ribossômico 16S/genética , Ribulose-Bifosfato Carboxilase/análise , Enxofre/análise , Isótopos de Enxofre/análise
14.
FEMS Microbiol Ecol ; 79(3): 649-60, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22092659

RESUMO

Groundwater polluted with methyl-tert-butyl ether (MTBE) and ammonium was investigated for chemolithoautotrophic CO(2) fixation capabilities based on detailed analyses of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large subunit genes. Samples retrieved from a groundwater conditioning unit, characterized by different redox conditions, were examined for the presence of form IA, form IC (cbbL) and form II (cbbM) RubisCO genes and transcripts obtained from DNA- and RNA-extracts. Form IA RubisCO sequences, which revealed a complex and distinct variety in different sampling stations, were expressed in the original groundwater and in samples amended with oxygen, but not in the aquifer groundwater enriched with nitrate. Form IC RubisCO genes were exclusively detected in groundwater supplied with oxygen and sequences were affiliated with cbbL genes in nitrifying bacteria. cbbM genes were not expressed in the oxygen-amended groundwater, probably due to the low CO(2) /O(2) substrate specificity of this enzyme. Most form II RubisCO transcripts were affiliated with RubisCO genes of denitrifiers, which are important residents in the groundwater supplied with nitrate. The distinct distribution pattern and diversity of RubisCO genes and transcripts obtained in this study suggest that the induction of different RubisCO enzymes is highly regulated and closely linked to the actual environmental conditions.


Assuntos
Água Subterrânea/microbiologia , Ribulose-Bifosfato Carboxilase/análise , Microbiologia da Água , Bactérias/enzimologia , Bactérias/genética , Sequência de Bases , Biodegradação Ambiental , Variação Genética , Éteres Metílicos/análise , Dados de Sequência Molecular , Filogenia , Compostos de Amônio Quaternário/análise , Ribulose-Bifosfato Carboxilase/química , Ribulose-Bifosfato Carboxilase/genética , Poluentes Químicos da Água/análise
15.
Plant Cell Environ ; 35(5): 966-81, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22091780

RESUMO

We investigated whether the degree of light inhibition of leaf respiration (R) differs among large Eucalyptus saligna grown in whole-tree chambers and exposed to present and future atmospheric [CO(2) ] and summer drought. Associated with month-to-month changes in temperature were concomitant changes in R in the light (R(light) ) and darkness (R(dark) ), with both processes being more temperature dependent in well-watered trees than under drought. Overall rates of R(light) and R(dark) were not significantly affected by [CO(2) ]. By contrast, overall rates of R(dark) (averaged across both [CO(2) ]) were ca. 25% lower under drought than in well-watered trees. During summer, the degree of light inhibition of leaf R was greater in droughted (ca. 80% inhibition) than well-watered trees (ca. 50% inhibition). Notwithstanding these treatment differences, an overall positive relationship was observed between R(light) and R(dark) when data from all months/treatments were combined (R(2) = 0.8). Variations in R(light) were also positively correlated with rates of Rubisco activity and nitrogen concentration. Light inhibition resulted in a marked decrease in the proportion of light-saturated photosynthesis respired (i.e. reduced R/A(sat) ). Collectively, these results highlight the need to account for light inhibition when assessing impacts of global change drivers on the carbon economy of tree canopies.


Assuntos
Dióxido de Carbono/metabolismo , Eucalyptus/metabolismo , Eucalyptus/efeitos da radiação , Luz , Fotossíntese/efeitos da radiação , Estresse Fisiológico , Austrália , Carbono/metabolismo , Respiração Celular , Escuridão , Secas , Nitrogênio/análise , Nitrogênio/metabolismo , Processos Fotoquímicos/efeitos da radiação , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Estômatos de Plantas/metabolismo , Estômatos de Plantas/efeitos da radiação , Transpiração Vegetal/efeitos da radiação , Ribulose-Bifosfato Carboxilase/análise , Ribulose-Bifosfato Carboxilase/metabolismo , Estações do Ano , Temperatura Ambiente , Árvores , Água
16.
Oecologia ; 169(2): 341-52, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22139428

RESUMO

This study evaluates acclimation of photosynthesis and stomatal conductance in three evolutionary lineages of C(3), C(3)-C(4) intermediate, and C(4) species grown in the low CO(2) and hot conditions proposed to favo r the evolution of C(4) photosynthesis. Closely related C(3), C(3)-C(4), and C(4) species in the genera Flaveria, Heliotropium, and Alternanthera were grown near 380 and 180 µmol CO(2) mol(-1) air and day/night temperatures of 37/29°C. Growth CO(2) had no effect on photosynthetic capacity or nitrogen allocation to Rubisco and electron transport in any of the species. There was also no effect of growth CO(2) on photosynthetic and stomatal responses to intercellular CO(2) concentration. These results demonstrate little ability to acclimate to low CO(2) growth conditions in closely related C(3) and C(3)-C(4) species, indicating that, during past episodes of low CO(2), individual C(3) plants had little ability to adjust their photosynthetic physiology to compensate for carbon starvation. This deficiency could have favored selection for more efficient modes of carbon assimilation, such as C(3)-C(4) intermediacy. The C(3)-C(4) species had approximately 50% greater rates of net CO(2) assimilation than the C(3) species when measured at the growth conditions of 180 µmol mol(-1) and 37°C, demonstrating the superiority of the C(3)-C(4) pathway in low atmospheric CO(2) and hot climates of recent geological time.


Assuntos
Dióxido de Carbono/metabolismo , Fotossíntese/fisiologia , Fenômenos Fisiológicos Vegetais , Aclimatação , Atmosfera , Clorofila/análise , Clorofila/metabolismo , Flaveria/crescimento & desenvolvimento , Flaveria/fisiologia , Heliotropium/crescimento & desenvolvimento , Heliotropium/fisiologia , Nitrogênio/análise , Nitrogênio/metabolismo , Folhas de Planta/fisiologia , Estômatos de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/análise , Ribulose-Bifosfato Carboxilase/metabolismo , Temperatura Ambiente
17.
Talanta ; 84(5): 1259-66, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21641435

RESUMO

In this work, a miniaturized, completely enclosed multisyringe-flow system is proposed for high-throughput purification of RuBisCO from Triticum aestivum extracts. The automated method capitalizes on the uptake of the target protein at 4°C onto Q-Sepharose Fast Flow strong anion-exchanger packed in a cylindrical microcolumn (105 × 4 mm) followed by a stepwise ionic-strength gradient elution (0-0.8 mol/L NaCl) to eliminate concomitant extract components and retrieve highly purified RuBisCO. The manifold is furnished downstream with a flow-through diode-array UV/vis spectrophotometer for real-time monitoring of the column effluent at the protein-specific wavelength of 280 nm to detect the elution of RuBisCO. Quantitation of RuBisCO and total soluble proteins in the eluate fractions were undertaken using polyacrylamide gel electrophoresis (PAGE) and the spectrophotometric Bradford assay, respectively. A comprehensive investigation of the effect of distinct concentration gradients on the isolation of RuBisCO and experimental conditions (namely, type of resin, column dimensions and mobile-phase flow rate) upon column capacity and analyte breakthrough was effected. The assembled set-up was aimed to critically ascertain the efficiency of preliminary batchwise pre-treatments of crude plant extracts (viz., polyethylenglycol (PEG) precipitation, ammonium sulphate precipitation and sucrose gradient centrifugation) in terms of RuBisCO purification and absolute recovery prior to automated anion-exchange column separation. Under the optimum physical and chemical conditions, the flow-through column system is able to admit crude plant extracts and gives rise to RuBisCO purification yields better than 75%, which might be increased up to 96 ± 9% with a prior PEG fractionation followed by sucrose gradient step.


Assuntos
Cromatografia por Troca Iônica/métodos , Análise de Injeção de Fluxo/métodos , Extratos Vegetais/química , Ribulose-Bifosfato Carboxilase/análise , Ribulose-Bifosfato Carboxilase/isolamento & purificação , Triticum/química , Automação , Análise de Injeção de Fluxo/instrumentação , Concentração de Íons de Hidrogênio , Seringas , Temperatura Ambiente , Fatores de Tempo
18.
PLoS One ; 6(1): e16351, 2011 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-21283730

RESUMO

Rubisco (ribulose-1, 5-bisphosphate carboxylase/oxygenase), a key enzyme of photosynthetic CO(2) fixation, is one of the most abundant proteins in both higher plants and algae. In this study, the differential expression of Rubisco in sporophytes and gametophytes of four seaweed species--Porphyra yezoensis, P. haitanensis, Bangia fuscopurpurea (Rhodophyte) and Laminaria japonica (Phaeophyceae)--was studied in terms of the levels of transcription, translation and enzyme activity. Results indicated that both the Rubisco content and the initial carboxylase activity were notably higher in algal gametophytes than in the sporophytes, which suggested that the Rubisco content and the initial carboxylase activity were related to the ploidy of the generations of the four algal species.


Assuntos
Expressão Gênica , Células Germinativas Vegetais/metabolismo , Ribulose-Bifosfato Carboxilase/análise , Alga Marinha/metabolismo , Esporos/metabolismo , Carbono-Carbono Ligases/metabolismo , Carbono-Carbono Liases/metabolismo , Enzimas/metabolismo , Células Germinativas Vegetais/química , Biossíntese de Proteínas , Alga Marinha/química , Especificidade da Espécie , Esporos/química , Esporos/genética , Transcrição Genética
19.
Plant Physiol ; 155(2): 956-62, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21177473

RESUMO

In C(3) plants, CO(2) assimilation is limited by ribulose 1,5-bisphosphate (RuBP) regeneration rate at high CO(2). RuBP regeneration rate in turn is determined by either the chloroplast electron transport capacity to generate NADPH and ATP or the activity of Calvin cycle enzymes involved in regeneration of RuBP. Here, transgenic tobacco (Nicotiana tabacum 'W38') expressing an antisense gene directed at the transcript of either the Rieske iron-sulfur protein of the cytochrome (Cyt) b(6)/f complex or the δ-subunit of chloroplast ATP synthase have been used to investigate the effect of a reduction of these complexes on chloroplast electron transport rate (ETR). Reductions in δ-subunit of ATP synthase content did not alter chlorophyll, Cyt b(6)/f complex, or Rubisco content, but reduced ETR estimated either from measurements of chlorophyll fluorescence or CO(2) assimilation rates at high CO(2). Plants with low ATP synthase content exhibited higher nonphotochemical quenching and achieved higher ETR per ATP synthase than the wild type. The proportional increase in ETR per ATP synthase complex was greatest at 35°C, showing that the ATP synthase activity can vary in vivo. In comparison, there was no difference in the ETR per Cyt b(6)/f complex in plants with reduced Cyt b(6)/f content and the wild type. The ETR decreased more drastically with reductions in Cyt b(6)/f complex than ATP synthase content. This suggests that chloroplast ETR is more limited by Cyt b(6)/f than ATP synthase content and is a potential target for enhancing photosynthetic capacity in crops.


Assuntos
ATPases de Cloroplastos Translocadoras de Prótons/metabolismo , Cloroplastos/enzimologia , Complexo Citocromos b6f/metabolismo , Fotossíntese , Tabaco/enzimologia , Dióxido de Carbono/metabolismo , Clorofila/análise , Transporte de Elétrons , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/fisiologia , Ribulose-Bifosfato Carboxilase/análise , Tabaco/fisiologia
20.
Ann Bot ; 107(2): 269-83, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21147832

RESUMO

BACKGROUND AND AIMS: Cleomaceae is one of 19 angiosperm families in which C(4) photosynthesis has been reported. The aim of the study was to determine the type, and diversity, of structural and functional forms of C(4) in genus Cleome. Methods Plants of Cleome species were grown from seeds, and leaves were subjected to carbon isotope analysis, light and scanning electron microscopy, western blot analysis of proteins, and in situ immunolocalization for ribulose bisphosphate carboxylase oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC). KEY RESULTS: Three species with C(4)-type carbon isotope values occurring in separate lineages in the genus (Cleome angustifolia, C. gynandra and C. oxalidea) were shown to have features of C(4) photosynthesis in leaves and cotyledons. Immunolocalization studies show that PEPC is localized in mesophyll (M) cells and Rubisco is selectively localized in bundle sheath (BS) cells in leaves and cotyledons, characteristic of species with Kranz anatomy. Analyses of leaves for key photosynthetic enzymes show they have high expression of markers for the C(4) cycle (compared with the C(3)-C(4) intermediate C. paradoxa and the C(3) species C. africana). All three are biochemically NAD-malic enzyme sub-type, with higher granal development in BS than in M chloroplasts, characteristic of this biochemical sub-type. Cleome gynandra and C. oxalidea have atriplicoid-type Kranz anatomy with multiple simple Kranz units around individual veins. However, C. angustifolia anatomy is represented by a double layer of concentric chlorenchyma forming a single compound Kranz unit by surrounding all the vascular bundles and water storage cells. CONCLUSIONS: NAD-malic enzyme-type C(4) photosynthesis evolved multiple times in the family Cleomaceae, twice with atriplicoid-type anatomy in compound leaves having flat, broad leaflets in the pantropical species C. gynandra and the Australian species C. oxalidea, and once by forming a single Kranz unit in compound leaves with semi-terete leaflets in the African species C. angustifolia. The leaf morphology of C. angustifolia, which is similar to that of the sister, C(3)-C(4) intermediate African species C. paradoxa, suggests adaptation of this lineage to arid environments, which is supported by biogeographical information.


Assuntos
Cleome/fisiologia , Cotilédone/anatomia & histologia , Fotossíntese , Folhas de Planta/anatomia & histologia , Evolução Biológica , Cleome/anatomia & histologia , Cleome/classificação , Cleome/enzimologia , Cleome/genética , Cotilédone/fisiologia , Fosfoenolpiruvato Carboxilase/análise , Fosfoenolpiruvato Carboxilase/metabolismo , Filogenia , Folhas de Planta/fisiologia , Proteínas de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/análise , Ribulose-Bifosfato Carboxilase/metabolismo
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