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1.
Plant Mol Biol ; 101(4-5): 439-454, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471780

RESUMO

KEY MESSAGE: Our study firstly elaborated the underlying mechanism of endogenous CH4-induced abiotic tolerance, along with an alteration of ABA sensitivity by mimicking the endogenous CH4 production in MtMCR transgenic Arabidopsis. Endogenous methane (CH4) production and/or emission have been ubiquitously observed in stressed plants. However, their physiological roles remain unclear. Here, the methyl-coenzyme M reductase gene from Methanobacterium thermoautotrophicum (MtMCR), encoding the enzyme of methanogenesis, was expressed in Arabidopsis thaliana, to mimic the production of endogenous CH4. In response to salinity and osmotic stress, MtMCR expression was up-regulated in transgenic plants, resulting in significant increase of endogenous CH4 levels. Similar results were observed in abscisic acid (ABA) treatment. The functions of endogenous CH4 were characterized by the changes in plant phenotypes related to stress and ABA sensitivity during the germination and post-germination periods. When challenged with osmotic stress, a reduction in water loss and stomatal closure, were observed. Redox homeostasis was reestablished during osmotic and salinity stress, and ion imbalance was also restored in salinity conditions. The expression of several stress/ABA-responsive genes was up-regulated, and ABA sensitivity, in particularly, was significantly altered in the MtMCR transgenic plants. Together, our genetic study for the first time elaborated the possible mechanism of endogenous CH4-enhanced salinity and osmotic tolerance, along with an alteration of ABA sensitivity. These findings thus provided novel cues for understanding the possible roles of endogenous CH4 in plants.


Assuntos
Arabidopsis/fisiologia , Metano/metabolismo , Oxirredutases/fisiologia , Estresse Fisiológico , Ácido Abscísico/metabolismo , Ácido Abscísico/fisiologia , Arabidopsis/enzimologia , Arabidopsis/genética , Homeostase , Pressão Osmótica , Oxirredução , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Estresse Salino
2.
Phys Chem Chem Phys ; 21(34): 18422-18457, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31410425

RESUMO

Our review addresses how material properties emerge from atomistic-level interactions in the case of lipid membrane nanostructures. We summarize advances in solid-state nuclear magnetic resonance (NMR) spectroscopy in conjunction with alternative small-angle X-ray and neutron scattering methods for investigating lipid flexibility and dynamics. Solid-state 2H NMR is advantageous in that it provides atomistically resolved information about the order parameters and mobility of phospholipids within liquid-crystalline membranes. Bilayer deformation in response to external perturbations occurs over a range of length scales and allows one to disentangle how the bulk material properties emerge from atomistic forces. Examples include structural parameters such as the area per lipid and volumetric thickness together with the moduli for elastic deformation. Membranes under osmotic stress allow one to further distinguish collective undulations and quasielastic contributions from short-range noncollective effects. Our approach reveals how membrane elasticity involves length scales ranging from the bilayer dimensions on down to the size of the flexible lipid segments. Collective lipid interactions of the order of the bilayer thickness and less occur in the liquid-crystalline state. Emergence of lipid material properties is significant for models of lipid-protein forces acting on the mesoscopic length scale that play key roles in biomembrane functions.


Assuntos
Bicamadas Lipídicas/química , Espectroscopia de Ressonância Magnética/métodos , Nanoestruturas/química , Fosfolipídeos/química , Membrana Celular/química , Elasticidade , Cristais Líquidos/química , Proteínas de Membrana/química , Modelos Químicos , Nêutrons , Pressão Osmótica , Espalhamento de Radiação , Termodinâmica , Raios X
3.
J Chem Phys ; 151(7): 074903, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438701

RESUMO

Ionic microgels are soft colloidal particles, composed of crosslinked polymer networks, which ionize and swell when dispersed in a good solvent. Swelling of these permeable, compressible particles involves a balance of electrostatic, elastic, and mixing contributions to the single-particle osmotic pressure. The electrostatic contribution depends on the distributions of mobile counterions and coions and of fixed charge on the polymers. Within the cell model, we employ two complementary methods to derive the electrostatic osmotic pressure of ionic microgels. In Poisson-Boltzmann (PB) theory, we minimize a free energy functional with respect to the electrostatic potential to obtain the bulk pressure. From the pressure tensor, we extract the electrostatic and gel contributions to the total pressure. In a statistical mechanical approach, we vary the free energy with respect to microgel size to obtain exact relations for the microgel electrostatic osmotic pressure. We present results for planar, cylindrical, and spherical geometries. For models of membranes and microgels with fixed charge uniformly distributed over their surface or volume, we derive analogs of the contact value theorem for charged colloids. We validate these relations by solving the PB equation and computing ion densities and osmotic pressures. When implemented within PB theory, the two methods yield identical electrostatic osmotic pressures for surface-charged microgels. For volume-charged microgels, the exact electrostatic osmotic pressure equals the average of the corresponding PB profile over the gel volume. We demonstrate that swelling of ionic microgels depends on the variation of the electrostatic pressure inside the particle and discuss implications for interpreting experiments.


Assuntos
Modelos Teóricos , Pressão Osmótica , Géis , Permeabilidade , Eletricidade Estática , Termodinâmica
4.
J Agric Food Chem ; 67(32): 8905-8918, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31380641

RESUMO

NAC TFs play crucial roles in response to abiotic stresses in plants. Here, ZmNAC071 was identified as a nuclear located transcriptional repressor. Overexpression of ZmNAC071 in Arabidopsis enhanced sensitivity of transgenic plants to ABA and osmotic stress. The expression levels of SODs, PODs, P5CSs, and AtMYB61 were inhibited by ZmNAC071, which results in reduced ROS scavenging and proline content, increased ROS level, and water loss. Besides, the expression levels of some ABA or abiotic stress-related genes, like ABIs, RD29A, DREBs, and LEAs were also significantly inhibited by ZmNAC071. Yeast one-hybrid assay demonstrated that ZmNAC071 specifically bound to the cis-acting elements containing CGT[G/A] core sequences in the promoter of stress-related genes, suggesting that ZmNAC071 may participate in the regulation of transcription of these genes through recognizing the core sequences CGT[G/A]. These results will facilitate further studies concerning the cis-elements and downstream genes targeted by ZmNAC071 in maize.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/fisiologia , Ácido Ascórbico/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/fisiologia , Fatores de Transcrição/genética , Zea mays/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação para Baixo/efeitos dos fármacos , Pressão Osmótica , Plantas Geneticamente Modificadas/genética , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Fatores de Transcrição/metabolismo
5.
J Sci Food Agric ; 99(15): 6973-6980, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31414485

RESUMO

BACKGROUND: Plants activate defense mechanisms to cope with adverse environmental conditions, leading to the accumulation and / or depletion of general and specialized metabolites. In this study, a multiplatform untargeted metabolomics strategy was employed to evaluate metabolic changes in strawberry fruit of cv. Camarosa grown under osmotic stress conditions. Liquid chromatography-mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) data from strawberries grown under two water-deficit conditions, irrigated at 95% crop evapotranspiration (ETc) and 85% ETc, and one excess salt condition with a 80 mmol L-1 NaCl solution, were analyzed to determine treatment effects on fruit metabolism. RESULTS: Multivariate principal component analysis, orthogonal projections to latent structures - discriminant analysis (OPLS-DA), and univariate statistical analyses were applied to the data set. While multivariate analyses showed group separation by treatment, T-tests and fold change revealed 12 metabolites differentially accumulated in strawberries from different treatments - among them phenolic compounds, glycerophospholipids, phytosterols, carbohydrates, and an aromatic amino acid. CONCLUSION: Untargeted metabolomic analysis allowed for the annotation of compounds differentially accumulated in strawberry fruit from plants grown under osmotic stress and non-stressed plants. The metabolic disturbance in plants under stress involved metabolites associated with the inhibition of reactive oxygen species and cell-wall and membrane lipid biosynthesis, which might serve as osmotic stress biomarkers. © 2019 Society of Chemical Industry.


Assuntos
Fragaria/química , Frutas/metabolismo , Cromatografia Líquida , Fragaria/crescimento & desenvolvimento , Fragaria/metabolismo , Frutas/química , Frutas/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Metabolômica , Pressão Osmótica , Cloreto de Sódio/análise , Cloreto de Sódio/metabolismo , Espectrometria de Massas em Tandem , Água/análise , Água/metabolismo
6.
J Zoo Wildl Med ; 50(2): 362-368, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31260201

RESUMO

Colloid osmotic pressure (COP) is an important component of the forces that manage capillary filtration and is determined by circulating plasma proteins. Patients affected by conditions resulting in hypoproteinemia often suffer severe hemodynamic derangements, including decreased COP. Because chronically debilitated sea turtles (CDT) present with severe hypoproteinemia, the objectives of this study were to 1) determine differences in plasma COP and blood analyte data (packed cell volume [PCV], sodium, chloride, plasma protein fractions) in CDT at admission compared with data from apparently healthy rehabilitated turtles at time of release (HRT) admitted from various stranding causes, and 2) to investigate correlations of COP with these selected blood analytes. COP, PCV, and most plasma protein fractions (excluding pre-albumin and γ-globulins) were significantly lower in CDT upon admission as compared with HRT. Sodium and chloride did not significantly differ between CDT and HRT. A significant increase was observed with PCV and all plasma protein fractions as COP increased. Of all protein fractions tested, albumin contributed the most toward COP (r2 = 0.88, P < 0.001). The results of this study suggest that COP is significantly lower in CDT as compared with HRT, providing insight into the complexity of this critical clinical condition and a small step in advancing the understanding of associated hemodynamic imbalances. Although COP analysis is not readily available as a diagnostic test, this preliminary baseline data suggests that additional research studies are warranted, given the potential for optimization of fluid therapy during rehabilitation of CDT.


Assuntos
Coloides , Pressão Osmótica/fisiologia , Plasma/química , Tartarugas/sangue , Animais , Proteínas Sanguíneas , Doença Crônica , Hidratação , Nível de Saúde , Valores de Referência
7.
Biophys Chem ; 253: 106211, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31280070

RESUMO

Living organisms can be encountered in nature under extreme conditions. At the seabed, pressure may reach 1000 bar. Yet microorganisms can be found that still function under these conditions. On the one hand, it is known that high pressure even has a positive effect on piezophile enzymes increasing their activity. On the other hand, such microorganisms might contain up to very high concentrations of osmolytes that counteract osmotic stress. To better understand high-pressure influences on biochemical systems, fundamental knowledge about pressure effects on thermodynamic properties of such osmolytes is important. However, literature data is scarce and experiments at high-pressure conditions are challenging. Hence, new high-pressure density data of aqueous osmolyte solutions were measured in this work at temperatures between 298.15 K and 318.15 K and at osmolyte concentrations up to 3 mol/kg water. Further, the thermodynamic model PC-SAFT has been applied recently to successfully model vapor pressures of water and density of water up to 10 kbar [M. Knierbein et al., Density variations of TMAO solutions in the kilobar range: experiments, PC-SAFT predictions, and molecular dynamics simulations, Biophysical chemistry, (2019)]. This allowed accurately predicting effects of temperature and osmolyte concentration on thermodynamic properties (especially mixture densities) up to very high pressures. Common osmolytes (trimethylamine-N-oxide, urea, ectoine, glycerol, glycine) as well as the dipeptides acetyl-N-methylglycine amide, acetyl-N-methylalanine amide, and acetyl-N-methylleucine amide were under investigation.


Assuntos
Amidas/química , Dipeptídeos/química , Termodinâmica , Simulação de Dinâmica Molecular , Pressão Osmótica , Pressão , Soluções , Água/química
8.
World J Microbiol Biotechnol ; 35(6): 90, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147784

RESUMO

The ability of plant growth promoting rhizobacteria (PGPR) for imparting abiotic stress tolerance to plants has been widely explored in recent years; however, the diversity and potential of these microbes have not been maximally exploited. In this study, we characterized four bacterial strains, namely, Pseudomonas aeruginosa PM389, Pseudomonas aeruginosa ZNP1, Bacillus endophyticus J13 and Bacillus tequilensis J12, for potential plant growth promoting (PGP) traits under osmotic-stress, induced by 25% polyethylene glycol (PEG) in the growth medium. Growth curve analysis was performed in LB medium with or without PEG, in order to understand the growth patterns of these bacteria under osmotic-stress. All strains were able to grow and proliferate under osmotic-stress, although their growth rate was slower than that under non-stressed conditions (LB without PEG). Bacterial secretions were analyzed for the presence of exopolysaccharides and phytohormones and it was observed that all four strains released these compounds into the media, both, under stressed and non-stressed conditions. In the Pseudomonas strains, osmotic stress caused a decrease in the levels of auxin (IAA) and cytokinin (tZ), but an increase in the levels of gibberellic acid. The Bacillus strains on the other hand showed a stress-induced increase in the levels of all three phytohormones. P. aeruginosa ZNP1 and B. endophyticus J13 exhibited increased EPS production under osmotic-stress. While osmotic stress caused a decrease in the levels of EPS in P. aeruginosa PM389, B. tequilensis J12 showed no change in EPS quantities released into the media under osmotic stress when compared to non-stressed conditions. Upon inoculating Arabidopsis thaliana seedlings with these strains individually, it was observed that all four strains were able to ameliorate the adverse effects of osmotic-stress (induced by 25% PEG in MS-Agar medium) in the plants, as evidenced by their enhanced fresh weight, dry weight and plant water content, as opposed to osmotic-stressed, non-inoculated plants.


Assuntos
Arabidopsis/microbiologia , Fenômenos Fisiológicos Bacterianos , Secas , Pressão Osmótica , Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/metabolismo , Polissacarídeos Bacterianos/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Bacillus/crescimento & desenvolvimento , Bacillus/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Citocininas/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Rizosfera , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Estresse Fisiológico/fisiologia
9.
Biol Bull ; 236(3): 224-241, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31167089

RESUMO

Salinity is one of the most crucial environmental factors that structures biogeographic boundaries of aquatic organisms, affecting distribution, abundance, and behavior. However, the association between behavior and gene regulation underlying acclimation to changes in salinity remains poorly understood. In this study, we investigated the effects of salinity stress on behavior (movement distance) and patterns of gene expression (using RNA sequencing) of the intertidal gastropod Batillaria attramentaria. We examined responses to short-term (1-hour) and long-term (30-day) acclimation to a range of salinities (43, 33 [control], 23, 13, and 3 psu). We found that the intertidal B. attramentaria is able to tolerate a broad range of salinity from 13 to 43 psu but not the acute low salinity of 3 psu. Behavioral experiments showed that salt stress significantly influenced snails' movement, with lower salinity resulting in shorter movement distance. Transcriptomic analyses revealed critical metabolic pathways and genes potentially involved in acclimation to salinity stress, including ionic and osmotic regulation, signal and hormonal transduction pathways, water exchange, cell protection, and gene regulation or epigenetic modification. In general, our study presents a robust, integrative laboratory-based approach to investigate the effects of salt stress on a nonmodel gastropod facing detrimental consequences of environmental change. The current genetic results provide a wealth of reference data for further research on mechanisms of ionic and osmotic regulation and adaptive evolution of this coastal gastropod.


Assuntos
Gastrópodes/fisiologia , Estresse Salino , Aclimatação/fisiologia , Animais , Comportamento Animal/fisiologia , Gastrópodes/genética , Gastrópodes/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Locomoção , Pressão Osmótica , Análise de Sequência de RNA
10.
PLoS Genet ; 15(6): e1008206, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31194741

RESUMO

The septation initiation network (SIN), composed of a conserved SepH (Cdc7p) kinase cascade, plays an essential role in fungal cytokinesis/septation and conidiation for asexual reproduction, while the mitogen-activated protein kinase (MAPK) pathway depends on successive signaling cascade phosphorylation to sense and respond to stress and environmental factors. In this study, a SepH suppressor-PomA in the filamentous fungus A. nidulans is identified as a negative regulator of septation and conidiation such that the pomA mutant is able to cure defects of sepH1 in septation and conidiation and overexpression of pomA remarkably suppresses septation. Under the normal cultural condition, SepH positively regulates the phosphorylation of MAPK-HogA, while PomA reversely affects this process. In the absence of PbsB (MAPKK, a putative upstream member of HogA), PomA and SepH are unable to affect the phosphorylation level of HogA. Under the osmostress condition, the induced phosphorylated HogA is capable of bypassing the requirement of SepH, a key player for early events during cytokinesis but not for MobA/SidB, the last one in the core SIN protein kinase cascade, indicating the osmotic stimuli-induced septation is capable of bypassing requirement of SepH but unable to bypass the whole SIN requirement. Findings demonstrate that crosstalk exists between the SIN and MAPK pathways. PomA and SepH indirectly regulate HogA phosphorylation through affecting HogA-P upstream kinases.


Assuntos
Aspergillus nidulans/genética , Proteínas Fúngicas/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Reprodução Assexuada/genética , Aspergillus nidulans/crescimento & desenvolvimento , Proteínas de Ciclo Celular/genética , Citocinese/genética , Mutação/genética , Proteínas Nucleares/genética , Pressão Osmótica , Fosforilação/genética , Polimorfismo de Nucleotídeo Único/genética , Proteínas Quinases/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/genética , Schizosaccharomyces/genética , Schizosaccharomyces/crescimento & desenvolvimento , Proteínas de Schizosaccharomyces pombe/genética , Transdução de Sinais/genética
11.
Food Microbiol ; 83: 36-47, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31202417

RESUMO

The genomic and metabolic diversity and features of Tetragenococcus halophilus, a moderately halophilic lactic acid bacterium, were investigated by pan-genome, transcriptome, and metabolite analyses. Phylogenetic analyses based on the 16S rRNA gene and genome sequences of 15 T. halophilus strains revealed their phylogenetic distinctness from other Tetragenococcus species. Pan-genome analysis of the T. halophilus strains showed that their carbohydrate metabolic capabilities were diverse and strain dependent. Aside from one histidine decarboxylase gene in one strain, no decarboxylase gene associated with biogenic amine production was identified from the genomes. However, T. halophilus DSM 20339T produced tyramine without a biogenic amine-producing decarboxylase gene, suggesting the presence of an unidentified tyramine-producing gene. Our reconstruction of the metabolic pathways of these strains showed that T. halophilus harbors a facultative lactic acid fermentation pathway to produce l-lactate, ethanol, acetate, and CO2 from various carbohydrates. The transcriptomic analysis of strain DSM 20339T suggested that T. halophilus may produce more acetate via the heterolactic pathway (including d-ribose metabolism) at high salt conditions. Although genes associated with the metabolism of glycine betaine, proline, glutamate, glutamine, choline, and citrulline were identified from the T. halophilus genomes, the transcriptome and metabolite analyses suggested that glycine betaine was the main compatible solute responding to high salt concentration and that citrulline may play an important role in the coping mechanism against high salinity-induced osmotic stresses. Our results will provide a better understanding of the genome and metabolic features of T. halophilus, which has implications for the food fermentation industry.


Assuntos
Enterococcaceae/genética , Enterococcaceae/metabolismo , Perfilação da Expressão Gênica , Genoma Bacteriano , Redes e Vias Metabólicas , Aminas Biogênicas/metabolismo , Genômica , Pressão Osmótica , Filogenia , RNA Ribossômico 16S/genética , Salinidade
12.
Chemosphere ; 232: 264-272, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31154187

RESUMO

Recovery of heavy metals in acid mine drainage (AMD) such as Mn, Fe, Cu, Zn, As, Cd and Pb was evaluated using volume retarded osmosis and low-pressure membrane (VRO-LPM) process. In VRO-LPM process, the draw solution (DS) is regenerated by the naturally generated pressure, giving its economic value. Ethylenediaminetetraacetic acid tetrasodium salt (EDTA-4Na) and Poly (sodium-4-styrenesulfonate, PSS-Na) were used and compared to determine more suitable DS in heavy metal recovery from the AMD. Forward osmosis (FO) and nanofiltration (NF) membrane were employed in VRO-LPM process, due to the low EDTA-4Na rejection (about 50%) in ultrafiltration (UF) process. For the FO part in the VRO-LPM process, PSS-Na had flux values of 0.12, 0.11 and 0.05 L m-2 h-1 and at osmotic pressure of 8.9, 12 and 13 bar, respectively. Unlike the flux values, the RSF of PSS remained at 0.01 mmol h-1 at all osmotic pressures. For EDTA-4Na, the flux values were 0.10, 0.06 and 0.04 L m-2 h-1, which are relatively higher than those of PSS-Na; and the RSF values were 0.1, 1.2, 2.2 mmol h-1, which are higher compared to those of PSS-Na. Unlike PSS-Na, RSF for EDTA-4Na increased as the concentration increases. In the NF part of the VRO-LPM process, PSS-Na had higher water flux and rejection than EDTA-4Na, and the flux and rejection both decreased with concentration for both PSS-Na and EDTA-4Na. The overall rejection in VRO-LPM process was over 95% for all heavy metal ions. Therefore, VRO-LPM process has proven its ability to be used in AMD treatment for heavy metal removal.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Membranas Artificiais , Osmose , Pressão Osmótica , Pressão , Ultrafiltração , Água
13.
Nat Plants ; 5(6): 559-560, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31182841
14.
Microbiol Res ; 223-225: 33-43, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178049

RESUMO

Mangroves, dominating tropical intertidal zones and estuaries, are among the most salt tolerant plants, and propagate through reproductive units called propagules. Similarly to plant seeds, propagules may harbor beneficial bacteria. Our hypothesis was that mangroves, being able to grow into seawater, should harbor bacteria able to interact with the host and to exert positive effects under salt stress, which could be exploited to improve crop production. Therefore, we isolated bacterial endophytes from mangrove propagules with the aim to test whether these bacteria have a beneficial potential on their natural host and on different crops such as barley and rice, cultivated under salt stress. The 172 bacterial isolates obtained were screened for plant growth promotion (PGP) activities in vitro, and the 12 most promising isolates were tested on barley under non-axenic conditions and salt stress. Gordonia terrae KMP456-M40 was the best performing isolate, increasing ear weight by 65%. Based on the in vivo PGP activity and the root colonization ability, investigated by fluorescence in situ hybridization and confocal microscopy, three strains were additionally tested on mangrove propagule germination and on rice growth. The most effective strain was again G. terrae KMP456-M40, which enhanced the root length of mangrove seedlings and the biomass of salt-stressed rice under axenic conditions up to 65% and 62%, respectively. We demonstrated that propagules, the reproductive units of mangroves, host beneficial bacteria that enhance the potential of mangrove seedlings establishment and confer salt tolerance to cereal crops.


Assuntos
Produtos Agrícolas , Grão Comestível/crescimento & desenvolvimento , Endófitos/fisiologia , Desenvolvimento Vegetal , Estresse Salino , Bactérias/classificação , Bactérias/isolamento & purificação , Biomassa , Endófitos/classificação , Endófitos/crescimento & desenvolvimento , Endófitos/isolamento & purificação , Genótipo , Germinação , Hordeum/crescimento & desenvolvimento , Hordeum/microbiologia , Hibridização in Situ Fluorescente , Oryza/microbiologia , Pressão Osmótica , Raízes de Plantas/microbiologia , Salinidade , Tolerância ao Sal , Plantas Tolerantes a Sal/microbiologia , Arábia Saudita , Água do Mar , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Sementes/crescimento & desenvolvimento , Sementes/microbiologia , Microbiologia do Solo , Áreas Alagadas
15.
Microbiol Res ; 223-225: 99-109, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178057

RESUMO

Streptococcus suis has received increasing attention for its involvement in severe infections in pigs and humans; however, their pathogenesis remains unclear. ClpX and ClpP, two subunits of the ATP-dependent caseinolytic protease Clp, play key roles in bacterial adaptation to various environmental stresses. In this study, a virulent S. suis serotype 2 strain, ZY05719, was employed to construct clpX and clpP deletion mutants (ΔclpX and ΔclpP, respectively) and their complementation strains. Both ΔclpX and ΔclpP displayed significantly reduced adaptability compared with the wild-type strain, evident through several altered phenotypes: formation of long cell chains, tendency to aggregate in culture, and reduced growth under acidic pH and H2O2-induced oxidative stress. ClpP and ClpX were required for the optimal growth during heat and cold stress, respectively. An in vitro experiment on RAW264.7 macrophage cells showed significantly increased sensitivity of ΔclpX and ΔclpP to phagocytosis compared with the wild-type strain. Mouse infection assays verified the deletion of clpX and clpP led to not only fewer clinical symptoms and lower mortality but also to a marked attenuation in bacterial colonization. These virulence-related phenotypes were restored by genetic complementation. Furthermore, the deletion of clpX or clpP caused a significant decrease in the expression of sodA, tpx, and apuA compared with the wild-type strain, suggesting that these genes may be regulated by ClpX and ClpP as downstream response factors to facilitate the bacterial tolerance against various environmental stresses. Taken together, these results suggest that ClpX and ClpP play important roles in stress tolerance for achieving the full virulence of S. suis serotype 2 during infection.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/metabolismo , Proteínas de Bactérias/metabolismo , Endopeptidase Clp/metabolismo , Chaperonas Moleculares/metabolismo , Streptococcus suis/metabolismo , Streptococcus suis/patogenicidade , Animais , Proteínas de Bactérias/genética , Biofilmes , Resposta ao Choque Frio , Endopeptidase Clp/genética , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Resposta ao Choque Térmico , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Camundongos , Chaperonas Moleculares/genética , Pressão Osmótica , Estresse Oxidativo , Fagocitose , Células RAW 264.7 , Infecções Estreptocócicas/microbiologia , Streptococcus suis/genética , Streptococcus suis/crescimento & desenvolvimento , Transcriptoma , Virulência/genética , Fatores de Virulência/genética , Fatores de Virulência/fisiologia
16.
Nat Plants ; 5(6): 581-588, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31182842

RESUMO

Chloroplasts are integral to sensing biotic and abiotic stress in plants, but their role in transducing Ca2+-mediated stress signals remains poorly understood1,2. Here we identify cMCU, a member of the mitochondrial calcium uniporter (MCU) family, as an ion channel mediating Ca2+ flux into chloroplasts in vivo. Using a toolkit of aequorin reporters targeted to chloroplast stroma and the cytosol in cMCU wild-type and knockout lines, we provide evidence that stress-stimulus-specific Ca2+ dynamics in the chloroplast stroma correlate with expression of the channel. Fast downstream signalling events triggered by osmotic stress, involving activation of the mitogen-activated protein kinases (MAPK) MAPK3 and MAPK6, and the transcription factors MYB60 and ethylene-response factor 6 (ERF6), are influenced by cMCU activity. Relative to wild-type plants, cMCU knockouts display increased resistance to long-term water deficit and improved recovery on rewatering. Modulation of stromal Ca2+ in specific processing of stress signals identifies cMCU as a component of plant environmental sensing.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Canais de Cálcio/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Cloroplastos/metabolismo , Cloroplastos/metabolismo , Proteínas Mitocondriais/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , Canais de Cálcio/genética , Proteínas de Transporte de Cátions/genética , Proteínas de Cloroplastos/genética , Cloroplastos/genética , Escherichia coli , Técnicas de Inativação de Genes , Sistema de Sinalização das MAP Quinases , Proteínas Mitocondriais/genética , Pressão Osmótica
17.
Int J Mol Sci ; 20(11)2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31181633

RESUMO

The growth and development of maize roots are closely related to drought tolerance. In order to clarify the molecular mechanisms of drought tolerance between different maize (Zea mays L.) varieties at the protein level, the isobaric tags for relative and absolute quantitation (iTRAQ) quantitative proteomics were used for the comparative analysis of protein expression in the seedling roots of the drought-tolerant Chang 7-2 and drought-sensitive TS141 maize varieties under 20% polyethylene glycol 6000 (PEG 6000)-simulated drought stress. We identified a total of 7723 differentially expressed proteins (DEPs), 1243 were significantly differentially expressed in Chang 7-2 following drought stress, 572 of which were up-regulated and 671 were down-regulated; 419 DEPs were identified in TS141, 172 of which were up-regulated and 247 were down-regulated. In Chang 7-2, the DEPs were associated with ribosome pathway, glycolysis/gluconeogenesis pathway, and amino sugar and nucleotide sugar metabolism. In TS141, the DEPs were associated with metabolic pathway, phenylpropanoid biosynthesis pathway, and starch and sucrose metabolism. Compared with TS141, the higher drought tolerance of Chang 7-2 root system was attributed to a stronger water retention capacity; the synergistic effect of antioxidant enzymes; the strengthen cell wall; the osmotic stabilization of plasma membrane proteins; the effectiveness of recycling amino acid; and an improvement in the degree of lignification. The common mechanisms of the drought stress response between the two varieties included: The promotion of enzymes in the glycolysis/gluconeogenesis pathway; cross-protection against the toxicity of aldehydes and ammonia; maintenance of the cell membrane stability. Based on the proteome sequencing information, the coding region sequences of eight DEP-related genes were analyzed at the mRNA level by quantitative real-time PCR (qRT-PCR). The findings of this study can inform the future breeding of drought-tolerant maize varieties.


Assuntos
Secas , Pressão Osmótica , Proteínas de Plantas/metabolismo , Proteoma/metabolismo , Zea mays/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Proteoma/genética , Zea mays/metabolismo
18.
J Vet Diagn Invest ; 31(4): 572-575, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31184294

RESUMO

We evaluated the oncotic pressure (plasma colloid osmotic pressure, πc) in a group of healthy, captive Asian elephants (Elephas maximus; n = 21) with a colloid osmometer with a membrane cutoff of >20,000 daltons. The median πc for these elephants was 26.3 mm Hg with an interquartile interval of 25.5-26.8 mm Hg. The mean πc value was 26.0 mm Hg ± SD 1.1. We found moderate correlation between albumin measured by electrophoresis and πc (r = 0.622; p = 0.003). After a 16-h water deprivation test in a subset of elephants (n = 16), a difference in πc was not detected, despite a significant increase in serum total proteins, urea, and osmolality. These results indicate that πc is not a sensitive indicator of hydration status in elephants after a short period of water deprivation. Use of oncotic pressure as a diagnostic tool in diseased Asian elephants warrants further investigation.


Assuntos
Eletroforese/veterinária , Elefantes/sangue , Pressão Osmótica , Privação de Água , Animais , Feminino , Masculino
19.
Plant Sci ; 284: 212-220, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31084874

RESUMO

Annexin is a multigene family that plays critical roles in plant stress responses and various cellular processes. Here, we reported the cloning and functional characterization of a novel rice annexin protein, OsANN3. We found that expression of OsANN3 was induced by polyethylene glycol (PEG) and abscisic acid (ABA) treatments. Overexpression of OsANN3 in rice significantly increased survival rates under drought stress, while knocking down OsANN3 resulted in sensitivity to drought. Meanwhile, OsANN3 overexpression showed enhanced sensitivity to exogenous ABA. Together with its Ca2+ and phospholipid binding activity, we proposed that when plants were subjected to drought stress, OsANN3 might mediate Ca2+ influx by binding to phospholipid to activate ABA signaling pathways. In addition, overexpression OsANN3 showed better growth under drought stress comparing to wild type, such as longer root length and more stomata closure for reducing water loss by regulating ABA-dependent stress response pathways.


Assuntos
Ácido Abscísico/fisiologia , Anexinas/fisiologia , Reguladores de Crescimento de Planta/fisiologia , Proteínas de Plantas/fisiologia , Anexinas/metabolismo , Cálcio/metabolismo , Desidratação , Oryza , Pressão Osmótica , Proteínas de Plantas/metabolismo , Estômatos de Plantas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Estresse Fisiológico
20.
Plant Sci ; 283: 329-342, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128704

RESUMO

Cold is an abiotic stress seriously threatening crop productivity by decreasing biomass production. The pollen tube is a target of cold stress, but also a useful model to address questions on cell wall biosynthesis. We here provide (immuno)cytological data relative to the impact of cold on the pollen tube cell wall. We clearly show that the growth pattern is severely affected by the stress, since the typical pulsed-growth mechanism accompanied by the periodic deposition of pectin rings is absent/severely reduced. Additionally, pectins and cellulose accumulate in bulges provoked by the stress, while callose, which colocalizes with pectins in the periodic rings formed during pulsed growth, accumulates randomly in the stressed samples. The altered distribution of the cell wall components is accompanied by differences in the localization of glucan synthases: cellulose synthase shows a more diffuse localization, while callose synthase shows a more frequent cytoplasmic accumulation, thereby denoting a failure in plasma membrane insertion. The cell wall observations are complemented by the analysis of intracellular Ca2+, pH and reactive oxygen species (ROS): while in the case of pH no major differences are observed, a less focused Ca2+ and ROS gradients are present in the stressed samples. The standard oscillatory growth of pollen tubes is recovered by transient changes of turgor pressure induced by hypoosmotic media. Overall our data contribute to the understanding of the impact that cold stress has on the normal development of the pollen tube and unveil the cell wall-related aberrant features accompanying the observed alterations.


Assuntos
Parede Celular/metabolismo , Tubo Polínico/crescimento & desenvolvimento , Tabaco/genética , Cálcio/metabolismo , Parede Celular/fisiologia , Celulose/metabolismo , Resposta ao Choque Frio , Técnica Indireta de Fluorescência para Anticorpo , Germinação , Glucanos/metabolismo , Concentração de Íons de Hidrogênio , Pressão Osmótica , Pectinas/metabolismo , Pólen/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tabaco/metabolismo
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