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61.
Mohd Zuwairi Saiman Karel Miettinen Natali Rianika Mustafa Young Hae Choi Robert Verpoorte Anna Elisabeth Schulte 《Plant Cell, Tissue and Organ Culture》2018,134(1):41-53
Previous studies showed that geraniol could be an upstream limiting factor in the monoterpenoid pathway towards the production of terpenoid indole alkaloid (TIA) in Catharanthus roseus cells and hairy root cultures. This shortage in precursor availability could be due to (1) limited expression of the plastidial geraniol synthase resulted in a low activity of the enzyme to catalyze the conversion of geranyl diphosphate to geraniol; or (2) the limitation of geraniol transport from plastids to cytosol. Therefore, in this study, C. roseus’s geraniol synthase (CrGES) gene was overexpressed in either plastids or cytosol of a non-TIA producing C. roseus cell line. The expression of CrGES in the plastids or cytosol was confirmed and the constitutive transformation lines were successfully established. A targeted metabolite analysis using HPLC shows that the transformed cell lines did not produce TIA or iridoid precursors unless elicited with jasmonic acid, as their parent cell line. This indicates a requirement for expression of additional, inducible pathway genes to reach production of TIA in this cell line. Interestingly, further analysis using NMR-based metabolomics reveals that the overexpression of CrGES impacts primary metabolism differently if expressed in the plastids or cytosol. The levels of valine, leucine, and some metabolites derived from the shikimate pathway, i.e. phenylalanine and tyrosine were significantly higher in the plastidial- but lower in the cytosolic-CrGES overexpressing cell lines. This result shows that overexpression of CrGES in the plastids or cytosol caused alteration of primary metabolism that associated to the plant cell growth and development. A comprehensive omics analysis is necessary to reveal the full effect of metabolic engineering. 相似文献
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64.
Nitrogen availability increases in a tundra ecosystem during five years of experimental permafrost thaw 下载免费PDF全文
Verity G. Salmon Patrick Soucy Marguerite Mauritz Gerardo Celis Susan M. Natali Michelle C. Mack Edward A. G. Schuur 《Global Change Biology》2016,22(5):1927-1941
Perennially frozen soil in high latitude ecosystems (permafrost) currently stores 1330–1580 Pg of carbon (C). As these ecosystems warm, the thaw and decomposition of permafrost is expected to release large amounts of C to the atmosphere. Fortunately, losses from the permafrost C pool will be partially offset by increased plant productivity. The degree to which plants are able to sequester C, however, will be determined by changing nitrogen (N) availability in these thawing soil profiles. N availability currently limits plant productivity in tundra ecosystems but plant access to N is expected improve as decomposition increases in speed and extends to deeper soil horizons. To evaluate the relationship between permafrost thaw and N availability, we monitored N cycling during 5 years of experimentally induced permafrost thaw at the Carbon in Permafrost Experimental Heating Research (CiPEHR) project. Inorganic N availability increased significantly in response to deeper thaw and greater soil moisture induced by Soil warming. This treatment also prompted a 23% increase in aboveground biomass and a 49% increase in foliar N pools. The sedge Eriophorum vaginatum responded most strongly to warming: this species explained 91% of the change in aboveground biomass during the 5 year period. Air warming had little impact when applied alone, but when applied in combination with Soil warming, growing season soil inorganic N availability was significantly reduced. These results demonstrate that there is a strong positive relationship between the depth of permafrost thaw and N availability in tundra ecosystems but that this relationship can be diminished by interactions between increased thaw, warmer air temperatures, and higher levels of soil moisture. Within 5 years of permafrost thaw, plants actively incorporate newly available N into biomass but C storage in live vascular plant biomass is unlikely to be greater than losses from deep soil C pools. 相似文献
65.
Anti‐Inflammatory and Antioxidant Actions of Copaiba Oil Are Related to Liver Cell Modifications in Arthritic Rats 下载免费PDF全文
66.
Latitudinal and altitudinal patterns of plant community diversity on mountain summits across the tropical Andes 下载免费PDF全文
Francisco Cuesta Priscilla Muriel Luis Daniel Llambí Stephan Halloy Nikolay Aguirre Stephan Beck Julieta Carilla Rosa Isela Meneses Soledad Cuello Alfredo Grau Luis E. Gámez Javier Irazábal Jorge Jácome Ricardo Jaramillo Lirey Ramírez Natalia Samaniego David Suárez‐Duque Natali Thompson Alfredo Tupayachi Paul Viñas Karina Yager María T. Becerra Harald Pauli William D. Gosling 《Ecography》2017,40(12):1381-1394
The high tropical Andes host one of the richest alpine floras of the world, with exceptionally high levels of endemism and turnover rates. Yet, little is known about the patterns and processes that structure altitudinal and latitudinal variation in plant community diversity. Herein we present the first continental‐scale comparative study of plant community diversity on summits of the tropical Andes. Data were obtained from 792 permanent vegetation plots (1 m2) within 50 summits, distributed along a 4200 km transect; summit elevations ranged between 3220 and 5498 m a.s.l. We analyzed the plant community data to assess: 1) differences in species abundance patterns in summits across the region, 2) the role of geographic distance in explaining floristic similarity and 3) the importance of altitudinal and latitudinal environmental gradients in explaining plant community composition and richness. On the basis of species abundance patterns, our summit communities were separated into two major groups: Puna and Páramo. Floristic similarity declined with increasing geographic distance between study‐sites, the correlation being stronger in the more insular Páramo than in the Puna (corresponding to higher species turnover rates within the Páramo). Ordination analysis (CCA) showed that precipitation, maximum temperature and rock cover were the strongest predictors of community similarity across all summits. Generalized linear model (GLM) quasi‐Poisson regression indicated that across all summits species richness increased with maximum air temperature and above‐ground necromass and decreased on summits where scree was the dominant substrate. Our results point to different environmental variables as key factors for explaining vertical and latitudinal species turnover and species richness patterns on high Andean summits, offering a powerful tool to detect contrasting latitudinal and altitudinal effects of climate change across the tropical Andes. 相似文献
67.
Monitoring on the Lowveld reaches of the Olifants River, Limpopo River System, and its Steelpoort, Blyde, Klaserie and Selati tributaries was initiated in 2009. Analysis of the 2009–2015 data from four Olifants River sites showed deterioration in the river’s ecological condition between where it enters the Lowveld and where it enters the Kruger National Park, with a slight recovery within the Kruger National Park. Physico-chemical, aquatic macroinvertebrate and fish data collected in 2009–2015 at six sites on the Steelpoort, Blyde, Klaserie and Selati tributaries of the Olifants River corroborated the ecological condition of these tributaries. The Selati was the most polluted and was in a critically modified condition, whereas the Klaserie and Steelpoort were in fair condition and the Blyde was in good condition. The Selati appeared to have a significant negative impact on the water quality, macroinvertebrates and fish of the Olifants River within the Kruger National Park. 相似文献
68.
JR Sara SM Marr WJ Smit LJC Erasmus WJ Luus-Powell 《African Journal of Aquatic Science》2017,42(3):287-291
Muscle tissue from 63 Synodontis zambezensis collected bimonthly in 2013 at Flag Boshielo Dam were analysed for metals and metalloids in a desktop human health risk assessment. The Hazard Quotient, based on a weekly meal of 67 g of fish muscle, exceeded the maximum acceptable level of one for lead, cobalt, cadmium, mercury, arsenic and selenium. The concentrations of these elements were higher in 2013 than those recorded in 2009 and 2012 in other fish species from Flag Boshielo Dam and these may pose a long-term health risk if consumed regularly by impoverished rural communities reliant on fish as a source of protein. 相似文献
69.
Gabriele Usai Flavia Mascagni Lucia Natali Tommaso Giordani Andrea Cavallini 《Tree Genetics & Genomes》2017,13(5):96
Genome skimming was performed, using Illumina sequence reads, in order to obtain a detailed comparative picture of the repetitive component of the genome of Populus species. Read sets of seven Populus and two Salix species (as outgroups) were subjected to clustering using RepeatExplorer (Novák et al. BMC Bioinformatics 11:378 2010). The repetitive portion of the genome ranged from 33.8 in Populus nigra to 46.5% in Populus tremuloides. The large majority of repetitive sequences were long terminal repeat-retrotransposons. Gypsy elements were over-represented compared to Copia ones, with a mean ratio Gypsy to Copia of 6.7:1. Satellite DNAs showed a mean genome proportion of 2.2%. DNA transposons and ribosomal DNA showed genome proportions of 1.8 and 1.9%, respectively. The other repeat types accounted for less of 1% each. Long terminal repeat-retrotransposons were further characterized, identifying the lineage to which they belong and studying the proliferation times of each lineage in the different species. The most abundant lineage was Athila, which showed large differences among species. Concerning Copia lineages, similar transpositional profiles were observed among all the analysed species; by contrast, differences in transpositional peaks of Gypsy lineages were found. The genome proportions of repeats were compared in the seven species, and a phylogenetic tree was built, showing species separation according to the botanical section to which the species belongs, although significant differences could be found within sections, possibly related to the different geographical origin of the species. Overall, the data indicate that the repetitive component of the genome in the poplar genus is still rapidly evolving. 相似文献
70.
Natali Rianika Mustafa Hye Kyong Kim Young Hae Choi Robert Verpoorte 《Biotechnology letters》2009,31(12):1967-1974
The effect of salicylic acid (SA) on the metabolic profile of Catharanthus roseus suspension cells throughout a time course (0, 6, 12, 24, 48 and 72 h after treatment) was investigated using NMR spectroscopy
and multivariate data analysis. When compared to control cell lines, SA-treated cells showed a high level of sugars (glucose
and sucrose) up to 48 h after treatment, followed by a dynamic change in amino acids, phenylpropanoids, and tryptamine. Additionally,
one compound—2,5-dihydroxybenzoic-5-O-glucoside—was detected solely in SA-treated cells. 相似文献