186,170 research outputs found
Metabolomic fingerprinting using nuclear magnetic resonance and multivariate data analysis as a tool for biodiversity informatics: A case study on the classification of Rosa x damascena
No full textMetabolomics is the comprehensive and simultaneous identification and quantification of metabolites in living cells. The
term metabolome is used to describe the observable chemical profile or fingerprint of the metabolites in a whole tissue.
Although being a new approach to study natural compounds, metabolomics uses traditional analytical techniques, including
extraction methods, which can be followed by nuclear magnetic resonance (NMR) spectroscopy and multivariate data
analysis. Although metabolomics has been successfully applied to quality control issues, the examples of its use for
chemosystematics are few. Thus, the analysis of four taxa of Rosa x damascena (R. damascena Mill., R. damascena
semperflorens, R. damascena trigintipetala and R. duchesse of Portland) was carried out by NMR spectroscopy as a tool for their
classification. A principal component analysis of the 1H NMR spectra, based on the metabolites found in organic and
aqueous fractions, showed a clear similarity of the samples. In particular, the major contributions from the aqueous fraction,
preliminarily considered as a biomarker of R. x damascena group, are the flavonoids kaempferol and quercetin, glycosilated
with glucose and rhamnose units. Our analysis demonstrated a close chemotaxonomic correlation among the four taxa,
making this method a reliable tool for chemosystematics
Ercolano MR, Carli P, Soria A, Termolino P, Grandillo S, Fogliano V, Barone A Molecular and biochemical profiling of tomato ecotype "Vesuvio" for fruit taste. International Workshop "Potential of metabolic profiling in plant science", Turin, November 13-14, pp. 78-79 (2003).
No full textPaviosides A-H, eight new oleane type saponins from Aesculus pavia with cytotoxic activity
No full textA phytochemical analysis of Aesculus pavia has led to the isolation of eight novel triterpenoid saponins, based on oleane type skeleton and named paviosides A-H (1a, 1b-4a, 4b). On the basis of chemical, and 2D NMR and mass spectrometry data, the structures of the new compounds were elucidated as 3-O-[beta-D-xylopyranosyl(1 -> 2)] [-beta-D-glucopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (1a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-glucopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (1b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-galactopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (2a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-galactopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (2b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (3a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (3b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl protoaescigenin (4a), and 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl protoaescigenin (4b). The compounds showed cytotoxic activity on J-774, murinemonocyte/macrophage, and WEHI-164, murine fibrosarcoma, cell lines. Among them, paviosides E-H (3a, 3b and 4a, 4b) showed higher activity with values ranging from 2.1 to 3.6 mu g/mL. Structure-activity relationship studies indicated the positive effect on the activity of xylose unit in the place of glucose, while a little detrimental effect is observed when glucose is substituted by galactose. The aglycone structure and the presence of a tigloyl or an angeloyl group at C-21 do not affect significantly the inhibitory activity on both tested cell lines. (C) 2012 Elsevier Ltd. All rights reserved
The Role of DNA in the Extracellular Environment: A Focus on NETs, RETs and Biofilms
No full textThe capacity to actively release genetic material into the extracellular environment has been reported for bacteria, archaea, fungi, and in general, for microbial communities, but it is also described in the context of multicellular organisms, animals and plants. This material is often present in matrices that locate outside the cells. Extracellular matrices have important roles in defense response and disease in microbes, animal and plants cells, appearing as barrier against pathogen invasion or for their recognition. Specifically, neutrophils extracellular traps (NETs) in animals and root extracellular traps (RETs) in plants, are recognized to be important players in immunity. A growing amount of evidence revealed that the extracellular DNA, in these contexts, plays an active role in the defense action. Moreover, the protective role of extracellular DNA against antimicrobials and mechanical stress also appears to be confirmed in bacterial biofilms. In parallel, recent efforts highlighted different roles of self (homologous) and non-self (heterologous) extracellular DNA, paving the way to discussions on its role as a “Damage-associated molecular pattern” (DAMP). We here provide an evolutionary overview on extracellular DNA in extracellular matrices like RETs, NETs, and microbial biofilms, discussing on its roles and inferring on possible novel functionalities
Metabolomics and molecular networking analyses in Arabidopsis thaliana show that extracellular self-DNA affects nucleoside/nucleotide cycles with accumulation of cAMP, cGMP and N6-methyl-AMP
No full textExtracellular DNA (exDNA) widely occurs in the environment due to release by either cell lysis or active secretion. The role of exDNA in plant-soil interactions has been investigated and inhibitory effects on the growth of conspecific individuals by their self-DNA have been reported. Transcriptome analysis in the model plant Arabidopsis thaliana showed a clear recognition by the plant roots of self- and nonself-exDNA, with inhibition occurring only after exposure to the former. In this study, an untargeted metabolomics approach was used to assess at molecular level the plant reactions to exDNA exposure. Thus, the effects on the metabolites profile of A. thaliana after exposure to self- and nonself-exDNA from plants and fish, were studied by NMR, LC-MS, chemometrics and molecular networking analyses. Results show that self-DNA significantly induces the accumulation of RNA constituents (nucleobases, ribonucleosides, dinucleotide and trinucleotide oligomers). Interestingly, AMP and GMP are found along with their cyclic analogues cAMP and cGMP, and in form of cyclic dimers (c-di-AMP and c-di-GMP). Also methylated adenosine monophosphate (m6AMP) and the dimeric dinucleotide N-methyladenylyl-(3’→5’) cytidine (m6ApC) increased only in the self-DNA treatment. Such striking evidence of self-DNA effects highlights a major role of exDNA in plant sensing of its environment
Fire occurrence and tussock size modulate facilitation by Ampelodesmos mauritanicus
No full textFacilitation has been reported for a wide range of plant communities, with evidence of interactions
between protégé and nurse plants shifting during their ontogenetic cycles. This study showed that large
Ampelodesmos mauritanicus tussocks can act as nurse for different species, but only after fire occurrence.
Large tussocks are typically composed by an external belt of living tillers surrounding dead standing
tillers in the inner area, thus being arranged as a “ring” shape. A low plant diversity in unburned sites,
dominated by intact Ampelodesmos tussocks, was related to the intense aboveground competition due to
space physical limitation by standing tillers, as well as to the reduction of light availability at ground
level. In contrast, after burning, tussocks resprouted only in their external belts, leaving empty inner
areas. During post-fire recovery, several species (e.g. Plantago spp., Trifolium spp., Carlina spp.) recolonize
the bare soil among different tussocks. On the other hand, a moss (Funaria hygrometrica) and several
herbaceous and woody plants (e.g. Spartium junceum, Calicotome villosa, Quercus pubescens subsp.
pubescens) were selectively distributed within the ash-full central areas of burned Ampelodesmos tus-
socks. In summary, the study reported evidence of changing prevalence in the interplay of competition
and facilitation effects between small and large Ampelodesmos tussocks, respectively. These results
suggest a broad significance of the interactions between fire occurrence and ontogenetic phases of the
dominant species in affecting the restoration dynamics of natural plant communities
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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