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71.
It is becoming more apparent that species richness alone many not be sufficient to fully understand ecosystem resilience but
that functional diversity (diversity of species having similar effects on an ecosystem process) may be more relevant. In particular,
response diversity (diversity of species that respond differently to disturbance) within functional groups (FG) is suggested
to be critical for resilience. We assess for the first time the use of response diversity as a measure of resilience in an
empirical study. Our experimental design consisted of sites with three disturbance intensities during a grazing exclosure
period and the same sites, 1 year later, after grazing. Plant FGs were identified based on effect traits related to nutrient
cycling and soil retention, and species richness within groups was assessed during exclosure and after grazing. To assess
if response diversity could predict loss of species richness (resilience analysis), response diversity was calculated only
during the exclosure period, based on traits related to grazing tolerance. We also assessed the contribution of richness to
response diversity during exclosure (redundancy analysis). Response diversity was significantly and highly correlated with
species richness within FGs during disturbance. That is, FGs with the lowest response diversity were the most affected, disappearing
when disturbance appeared. Richness within FGs during exclosure was not significantly correlated with response diversity,
showing that higher richness does not ensure resilience. We conclude that response diversity can be used to predict which
FGs are more resilient, and hence, less vulnerable to future disturbance. 相似文献
72.
García Graciela Gutiérrez Verónica Ríos Néstor Papa Nicolás Serra Sebastián Loureiro Marcelo 《Hydrobiologia》2020,847(19):4141-4142
Hydrobiologia - Due to an unfortunate turn of events, the incorrect caption of Fig. 2 appeared in the original publication. Figure 2 and its correct caption is published here and should be treated... 相似文献
73.
Elisa V. Bertini Carlos G. Nieto Peñalver Ana C. Leguina Verónica P. Irazusta Lucía I. C. de Figueroa 《Antonie van Leeuwenhoek》2014,106(3):497-506
The endophytic bacterium Gluconacetobacter diazotrophicus colonizes a broad range of host plants. Its plant growth-promoting capability is related to the capacity to perform biological nitrogen fixation, the biosynthesis of siderophores, antimicrobial substances and the solubilization of mineral nutrients. Colonization of and survival in these endophytic niche requires a complex regulatory network. Among these, quorum sensing systems (QS) are signaling mechanisms involved in the control of several genes related to microbial interactions, host colonization and stress survival. G. diazotrophicus PAL5 possesses a QS composed of a luxR and a luxI homolog, and produces eight molecules from the AHL family as QS signals. In this report data are provided showing that glucose concentration modifies the relative levels of these signal molecules. The activity of G. diazotrophicus PAL5 QS is also altered in presence of other carbon sources and under saline stress conditions. Inactivation of the QS system of G. diazotrophicus PAL5 by means of a quorum quenching strategy allowed the identification of extracellular and intracellular proteins under the control of this regulatory mechanism. 相似文献
74.
Jesús Sot Marco?M. Manni Ana?R. Viguera Verónica Casta?eda Ainara Cano Cristina Alonso David Gil Mikel Valle Alicia Alonso Félix?M. Go?i 《Biophysical journal》2014,107(12):2828-2837
The origin of resistance to detergent solubilization in certain membranes, or membrane components, is not clearly understood. We have studied the solubilization by Triton X-100 of binary mixtures composed of egg sphingomyelin (SM) and either ceramide, diacylglycerol, or cholesterol. Solubilization has been assayed in the 4–50°C range, and the results are summarized in a novel, to our knowledge, form of plots, that we have called temperature-solubilization diagrams. Despite using a large detergent excess (lipid/detergent 1:20 mol ratio) and extended solubilization times (24–48 h) certain mixtures were not amenable to Triton X-100 solubilization at one or more temperatures. DSC of all the lipid mixtures, and of all the lipid + detergent mixtures revealed that detergent resistance was associated with the presence of gel domains at the assay temperature. Once the system melted down, solubilization could occur. In general adding high-melting lipids limited the solubilization, whereas the addition of low-melting lipids promoted it. Lipidomic analysis of Madin-Darby canine kidney cell membranes and of the corresponding detergent-resistant fraction indicated a large enrichment of the nonsolubilized components in saturated diacylglycerol and ceramide. SM-cholesterol mixtures were special in that detergent solubilization was accompanied, for certain temperatures and compositions, by an independent phenomenon of reassembly of the partially solubilized lipid bilayers. The temperature at which lysis and reassembly prevailed was ∼25°C, thus for some SM-cholesterol mixtures solubilization occurred both above and below 25°C, but not at that temperature. These observations can be at the origin of the detergent resistance effects observed with cell membranes, and they also mean that cholesterol-containing detergent-resistant membrane remnants cannot correspond to structures existing in the native membrane before detergent addition. 相似文献
75.
Age of spent Octopus vulgaris and stress mark analysis using beaks of wild individuals 总被引:1,自引:0,他引:1
Catalina Perales-Raya Alba Jurado-Ruzafa Aurora Bartolomé Verónica Duque María Nazaret Carrasco Eugenio Fraile-Nuez 《Hydrobiologia》2014,725(1):105-114
Age estimation of the cephalopod Octopus vulgaris by using beaks has improved in recent years, but maximum age and longevity in the wild have not been confirmed due to the low availability of senescent wild octopuses. In this study, a beak analysis of lateral wall surfaces (LWS) from 20 spent specimens confirmed the 1-year lifecycle of the species in Central East Atlantic waters. Stress marks (checks) were clearly located in the daily increment sequence of rostrum sagittal sections (RSS). The highest daily variations in sea surface temperature (ΔT) that occurred during the last months of their lifetimes coincided with the locations of the marks on the beak, enabling confirmation of O. vulgaris beaks as life recorders for the first time. It also supports the daily deposition of RSS beak increments in the wild. Individuals were grouped into two main zones, at 20ºN and 18ºN, respectively. Both groups showed different thermal check patterns, in accordance with the oceanographic differences. Two other checks (not coinciding with high values of ΔT) were observed in RSS at averages of 15 and 28 days before death, respectively, which were interpreted as responding to senescent-related events. 相似文献
76.
Alejandra Martinez Gonzalo Peluffo Ariel A. Petruk Martín Hugo Dolores Pi?eyro Verónica Demicheli Diego M. Moreno Analía Lima Carlos Batthyány Rosario Durán Carlos Robello Marcelo A. Martí Nicole Larrieux Alejandro Buschiazzo Madia Trujillo Rafael Radi Lucía Piacenza 《The Journal of biological chemistry》2014,289(18):12760-12778
Trypanosoma cruzi, the causative agent of Chagas disease, contains exclusively iron-dependent superoxide dismutases (Fe-SODs) located in different subcellular compartments. Peroxynitrite, a key cytotoxic and oxidizing effector biomolecule, reacted with T. cruzi mitochondrial (Fe-SODA) and cytosolic (Fe-SODB) SODs with second order rate constants of 4.6 ± 0.2 × 104
m−1 s−1 and 4.3 ± 0.4 × 104
m−1 s−1 at pH 7.4 and 37 °C, respectively. Both isoforms are dose-dependently nitrated and inactivated by peroxynitrite. Susceptibility of T. cruzi Fe-SODA toward peroxynitrite was similar to that reported previously for Escherichia coli Mn- and Fe-SODs and mammalian Mn-SOD, whereas Fe-SODB was exceptionally resistant to oxidant-mediated inactivation. We report mass spectrometry analysis indicating that peroxynitrite-mediated inactivation of T. cruzi Fe-SODs is due to the site-specific nitration of the critical and universally conserved Tyr35. Searching for structural differences, the crystal structure of Fe-SODA was solved at 2.2 Å resolution. Structural analysis comparing both Fe-SOD isoforms reveals differences in key cysteines and tryptophan residues. Thiol alkylation of Fe-SODB cysteines made the enzyme more susceptible to peroxynitrite. In particular, Cys83 mutation (C83S, absent in Fe-SODA) increased the Fe-SODB sensitivity toward peroxynitrite. Molecular dynamics, electron paramagnetic resonance, and immunospin trapping analysis revealed that Cys83 present in Fe-SODB acts as an electron donor that repairs Tyr35 radical via intramolecular electron transfer, preventing peroxynitrite-dependent nitration and consequent inactivation of Fe-SODB. Parasites exposed to exogenous or endogenous sources of peroxynitrite resulted in nitration and inactivation of Fe-SODA but not Fe-SODB, suggesting that these enzymes play distinctive biological roles during parasite infection of mammalian cells. 相似文献
77.
Alberto Zambrano Verónica García-Carpizo María Esther Gallardo Raquel Villamuera Maria Ana Gómez-Ferrería Angel Pascual Nicolas Buisine Laurent M. Sachs Rafael Garesse Ana Aranda 《The Journal of cell biology》2014,204(1):129-146
There is increasing evidence that the thyroid hormone (TH) receptors (THRs) can play a role in aging, cancer and degenerative diseases. In this paper, we demonstrate that binding of TH T3 (triiodothyronine) to THRB induces senescence and deoxyribonucleic acid (DNA) damage in cultured cells and in tissues of young hyperthyroid mice. T3 induces a rapid activation of ATM (ataxia telangiectasia mutated)/PRKAA (adenosine monophosphate–activated protein kinase) signal transduction and recruitment of the NRF1 (nuclear respiratory factor 1) and THRB to the promoters of genes with a key role on mitochondrial respiration. Increased respiration leads to production of mitochondrial reactive oxygen species, which in turn causes oxidative stress and DNA double-strand breaks and triggers a DNA damage response that ultimately leads to premature senescence of susceptible cells. Our findings provide a mechanism for integrating metabolic effects of THs with the tumor suppressor activity of THRB, the effect of thyroidal status on longevity, and the occurrence of tissue damage in hyperthyroidism. 相似文献
78.
Laura Azeredo Miranda Mota Jo?o Roberto Neto Ver?nica Gomes Monteiro Caroliny Samary Silva Lobato Marco Antonio de Oliveira Maura da Cunha Heloisa D’ávila Sérgio Henrique Seabra Patrícia Torres Bozza Renato Augusto DaMatta 《Memórias do Instituto Oswaldo Cruz》2014,109(6):767-774
Lipid bodies [lipid droplets (LBs)] are lipid-rich organelles involved in lipid
metabolism, signalling and inflammation. Recent findings suggest a role for LBs in
host response to infection; however, the potential functions of this organelle
in Toxoplasma gondii infection and how it alters macrophage
microbicidal capacity during infection are not well understood. Here, we investigated
the role of host LBs in T. gondii infection in mouse peritoneal
macrophages in vitro. Macrophages cultured with mouse serum (MS) had higher numbers
of LBs than those cultured in foetal bovine serum and can function as a model to
study the role of LBs during intracellular pathogen infection. LBs were found in
association with the parasitophorous vacuole, suggesting that T. gondii
may benefit from this lipid source. Moreover, increased numbers of
macrophage LBs correlated with high prostaglandin E2 (PGE2) production and decreased
nitric oxide (NO) synthesis. Accordingly, LB-enriched macrophages cultured with MS
were less efficient at controlling T. gondii growth. Treatment of
macrophages cultured with MS with indomethacin, an inhibitor of PGE2 production,
increased the microbicidal capacity against T. gondii. Collectively,
these results suggest that culture with MS caused a decrease in microbicidal activity
of macrophages against T. gondii by increasing PGE2 while lowering
NO production. 相似文献
79.
80.
Verónica Corrales-Sánchez María del Mar Noblejas-López Cristina Nieto-Jiménez Javier Pérez-Peña Juan Carlos Montero Miguel Burgos Eva M. Galán-Moya Atanasio Pandiella Alberto Ocaña 《Journal of cellular and molecular medicine》2020,24(5):3117-3127
Identification of druggable vulnerabilities is a main objective in triple-negative breast cancer (TNBC), where no curative therapies exist. Gene set enrichment analyses (GSEA) and a pharmacological evaluation using a library of compounds were used to select potential druggable combinations. MTT and studies with semi-solid media were performed to explore the activity of the combinations. TNBC cell lines (MDAMB-231, BT549, HS-578T and HCC3153) and an additional panel of 16 cell lines were used to assess the activity of the two compounds. Flow cytometry experiments and biochemical studies were also performed to explore the mechanism of action. GSEA were performed using several data sets (GSE21422, GSE26910, GSE3744, GSE65194 and GSE42568), and more than 35 compounds against the identified functions were evaluated to discover druggable opportunities. Analyses done with the Chou and Talalay algorithm confirmed the synergy of dasatinib and olaparib. The combination of both agents significantly induced apoptosis in a caspase-dependent manner and revealed a pleotropic effect on cell cycle: Dasatinib arrested cells in G0/G1 and olaparib in G2/M. Dasatinib inhibited pChk1 and induced DNA damage measured by pH2AX, and olaparib increased pH3. Finally, the effect of the combination was also evaluated in a panel of 18 cell lines representative of the most frequent solid tumours, observing a particularly synergism in ovarian cancer. Breast cancer, triple negative, dasatinib, olaparib, screening. 相似文献