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1.
World J Microbiol Biotechnol ; 35(11): 170, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673816

RESUMO

Debaryomyces hansenii is a halotolerant yeast of importance in basic and applied research. Previous reports hinted about possible links between saline and oxidative stress responses in this yeast. The aim of this work was to study that hypothesis at different molecular levels, investigating after oxidative and saline stress: (i) transcription of seven genes related to oxidative and/or saline responses, (ii) activity of two main anti-oxidative enzymes, (iii) existence of common metabolic intermediates, and (iv) generation of damages to biomolecules as lipids and proteins. Our results showed how expression of genes related to oxidative stress was induced by exposure to NaCl and KCl, and, vice versa, transcription of some genes related to osmotic/salt stress responses was regulated by H2O2. Moreover, and contrary to S. cerevisiae, in D. hansenii HOG1 and MSN2 genes were modulated by stress at their transcriptional level. At the enzymatic level, saline stress also induced antioxidative enzymatic defenses as catalase and glutathione reductase. Furthermore, we demonstrated that both stresses are connected by the generation of intracellular ROS, and that hydrogen peroxide can affect the accumulation of in-cell sodium. On the other hand, no significant alterations in lipid oxidation or total glutathione content were observed upon exposure to both stresses tested. The results described in this work could help to understand the responses to both stressors, and to improve the biotechnological potential of D. hansenni.


Assuntos
Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Estresse Oxidativo/fisiologia , Saccharomycetales/fisiologia , Estresse Salino/fisiologia , Antioxidantes , Catalase/metabolismo , Proteínas de Ligação a DNA/genética , Regulação Fúngica da Expressão Gênica , Genes Fúngicos/genética , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio , Metabolismo dos Lipídeos , Osmorregulação/genética , Osmorregulação/fisiologia , Estresse Oxidativo/genética , Cloreto de Potássio/metabolismo , Proteômica , Saccharomycetales/genética , Estresse Salino/genética , Sódio/metabolismo , Cloreto de Sódio/metabolismo , Fatores de Transcrição/genética
2.
Int J Mol Sci ; 20(19)2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31546641

RESUMO

Chloride (Cl-) has traditionally been considered a micronutrient largely excluded by plants due to its ubiquity and abundance in nature, its antagonism with nitrate (NO3-), and its toxicity when accumulated at high concentrations. In recent years, there has been a paradigm shift in this regard since Cl- has gone from being considered a harmful ion, accidentally absorbed through NO3- transporters, to being considered a beneficial macronutrient whose transport is finely regulated by plants. As a beneficial macronutrient, Cl- determines increased fresh and dry biomass, greater leaf expansion, increased elongation of leaf and root cells, improved water relations, higher mesophyll diffusion to CO2, and better water- and nitrogen-use efficiency. While optimal growth of plants requires the synchronic supply of both Cl- and NO3- molecules, the NO3-/Cl- plant selectivity varies between species and varieties, and in the same plant it can be modified by environmental cues such as water deficit or salinity. Recently, new genes encoding transporters mediating Cl- influx (ZmNPF6.4 and ZmNPF6.6), Cl- efflux (AtSLAH3 and AtSLAH1), and Cl- compartmentalization (AtDTX33, AtDTX35, AtALMT4, and GsCLC2) have been identified and characterized. These transporters have proven to be highly relevant for nutrition, long-distance transport and compartmentalization of Cl-, as well as for cell turgor regulation and stress tolerance in plants.


Assuntos
Osmorregulação/fisiologia , Plantas/metabolismo , Cloreto de Sódio/metabolismo , Transporte de Íons/genética , Transporte de Íons/fisiologia , Micronutrientes/metabolismo , Nitratos/metabolismo , Nitrogênio/metabolismo , Nutrientes/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Salinidade , Transdução de Sinais , Água/metabolismo
3.
Zoolog Sci ; 36(3): 215-222, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251490

RESUMO

Anurans occupy a wide variety of habitats of diverse salinities, and their osmoregulatory ability is strongly regulated by hormones. In this study, we compared the adaptability and hormonal responses to osmotic stress between two kajika frogs, Buergeria japonica (B.j.) and B. buergeri, (B.b.), which inhabit coastal brackish waters (BW) in the Ryukyu Islands and freshwater (FW) in the Honshu, respectively. Both hematocrit and plasma Na+ concentration were significantly higher in B.j. than in B.b. when both were kept in FW. After transfer to one-third seawater (simulating the natural BW environment), which is slightly hypertonic to their body fluids, their body mass decreased and plasma Na concentration increased significantly in both species. After transfer, plasma Na+ concentration increased significantly in both species. We examined the gene expression of two major osmoregulatory hormones, arginine vasotocin (AVT) and atrial natriuretic peptide (ANP), after partial cloning of their cDNAs. ANP mRNA levels were more than 10-fold higher in B.j. than in B.b. in FW, but no significant difference was observed for AVT mRNA levels due to high variability, although the mean value of B.j. was twice that of B.b. Both AVT and ANP mRNA levels increased significantly after transfer to BW in B.b. but not in B.j., probably because of the high levels in FW. These results suggest that B.j. maintains high plasma Na+ concentration and anp gene expression to prepare for the future encounter of the high salinity. The unique preparatory mechanism may allow B.j. wide distribution in oceanic islands.


Assuntos
Anuros/fisiologia , Ecossistema , Águas Salinas/química , Tolerância ao Sal/fisiologia , Animais , Fator Natriurético Atrial/metabolismo , Clonagem Molecular , Regulação da Expressão Gênica/efeitos dos fármacos , Japão , Masculino , Osmorregulação/fisiologia , RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Cloreto de Sódio/farmacologia , Vasotocina/metabolismo
4.
Plant Physiol Biochem ; 139: 171-178, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30897508

RESUMO

To enhance crop productivity and minimize the harmful effects of various environmental stresses, such as salinity and drought, farmers often use mineral fertilizers. However, inadequate or excessive fertilization can reduce plant growth and nutritive quality and contribute to soil degradation and environmental pollution. This study investigated the effects of salinity (0, 100 or 150 mM NaCl) and nitrogen form (sole NO3- or NH4+, or combined NO3-:NH4+ at 25:75 or 50:50) on growth, photosynthesis, and water and ion status of a commercial variety of maize (Zea mays SY Sincero). In the absence of NaCl, the media containing ammonium only or both nitrogen forms had higher aboveground growth rates than that containing nitrate only. Indeed, the maize growth, expressed as leaf dry matter, seen on NH4+ in the absence of salinity, was nearly double the biomass compared to that with NO3-treatment. Irrespective of N form, the presence of NaCl severely reduced leaf and roots growth; the presence of ammonium in the nutrient solution diminished these negative effects. Compared to the NH4+ only and combined treatments, the leaves of plants in the NO3--only medium showed signs of nitrogen deficiency (general chlorosis), which was more pronounced in the lower than upper leaves, indicating that nitrate is partly replaced by chloride during root uptake. NH4+ favored maize growth more than NO3-, especially when exposed to saline conditions, and may improve the plant's capacity to osmotically adjust to salinity by accumulating inorganic solutes.


Assuntos
Nitrogênio/metabolismo , Osmorregulação/fisiologia , Fotossíntese/fisiologia , Zea mays/crescimento & desenvolvimento , Compostos de Amônio/metabolismo , Pressão Osmótica , Prolina/metabolismo , Estresse Salino , Água/metabolismo , Zea mays/fisiologia
5.
Clin Interv Aging ; 14: 225-229, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30787598

RESUMO

Purpose: Water balance disorders are associated with a high risk of death in elderly patients. The role of osmotic stress intensity and its direction toward hypo- or hypernatremia is a matter of controversy regarding patients' survival. The aims of this study were, first, to measure the frequency of cellular hydration disorders in patients over 75 years old hospitalized in nephrology department for reversible acute renal failure, and second, to compare the impact of hyperhydration and hypohydration on the risk of death at 6 months. Patients and methods: We retrospectively studied the data of 279 patients with chronic kidney disease (CKD), aged 75 years or older, with pre-renal azotemia who experienced dysnatremia. We classified them according to natremia levels and compared their outcome in univariate and multivariate analysis. Results: The patients were on average 83.2±5.4 years old. Among them, 128 were normonatremic, 82 were hyponatremic and 69 were hypernatremic. Osmotic stress intensity appreciated by the variation rate of natremia did not differ significantly between hyper- and hyponatremic patients. Patients had CKD stage 3B and 4 with acute kidney injury (AKI) of different severities. We observed that only hypernatremia was linked to death in the first 6 months following hospital discharge. Conclusion: Hypernatremia is a strong predictor of fatal outcome in elderly patients suffering from chronic kidney impairment and referred for pre-renal azotemia.


Assuntos
Lesão Renal Aguda/mortalidade , Lesão Renal Aguda/fisiopatologia , Osmorregulação/fisiologia , Lesão Renal Aguda/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Azotemia/epidemiologia , Feminino , Humanos , Hipernatremia/epidemiologia , Hiponatremia/epidemiologia , Masculino , Pressão Osmótica/fisiologia , Estudos Retrospectivos , Fatores de Risco
6.
Bull Exp Biol Med ; 166(4): 417-420, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30788735

RESUMO

We developed an approach for quantitative assay of injected vasopressin in urine samples by ELISA under conditions of physiological suppression of hormone secretion from the neurohypophysis into the blood. In experiments on unanesthetized rats, water load (5 ml/100 g body weight) almost completely blocked secretion of arginine-vasopressin. Injection of arginine-vasopressin in a dose of 0.1 nmol/100 g body weight after water load enhanced reabsorption of solute-free water and renal excretion of Na+, K+, and Mg2+ by 13.3, 5.5, and 5.0 times, respectively; urinary excretion of Ca2+ remained unchanged. It was found that urinary excretion of arginine-vasopressin directly correlated with reabsorption of solute-free water and renal sodium excretion.


Assuntos
Arginina Vasopressina/urina , Reabsorção Renal/fisiologia , Sódio/metabolismo , Água/metabolismo , Animais , Cálcio/metabolismo , Ensaio de Imunoadsorção Enzimática , Magnésio/metabolismo , Osmorregulação/fisiologia , Potássio/metabolismo , Ratos , Ratos Wistar
7.
Acta Histochem ; 121(3): 268-276, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30642627

RESUMO

Dp71 is the major form of dystrophins (Dp) in the supraoptic nucleus (SON) and in the neural lobe of hypophysis (NL/HP). Dp71-null mice exhibit a hypo-osmolar status attributed to an altered osmosensitivity of the SON and to a perturbed vasopressinergic axis. Because oxytocin (OT) is implicated in osmoregulation via natriuresis, this study explored the oxytocinergic axis in Dp71-null mice after salt-loading (SL). Under normosmolar conditions, OT-mRNA expression was higher in the Dp71-null SON compared to wild-type (wt) and the OT peptide level has not changed. Dp-immunostaining was localized in astrocytes end-feet surrounding vessels in wt SON. This distribution changed in Dp71-null SON, Dp being detected in OT-soma of MCNs. nNOS and NADPH-diaphorase levels increased in the OT area of the Dp71-null SON compared to wt. In the NL/HP, OT level reduced in Dp71-null mice and Dp localization changed from pituicytes end-feet in wt SON to OT terminals in Dp71-null SON. Salt-Loading resulted in an increase of OT-mRNA and peptide levels in wt SON but had no effect in Dp71-null SON. In the NL/HP, OT content was reduced after SL. For Dp71-null mice, OT level, already low in control, was not modified by SL. Dp level was not affected by SL in the SON nor in the NL/HP. Our data confirmed the importance of Dp71 for the SON functionality in osmoregulation. The localization of Dp71 at the glial-vascular interface could be associated with SON osmosensitivity, leading to an adequate OT synthesis in the SON and release from the NL/HP upon plasmatic hyperosmolality.


Assuntos
Distrofina/deficiência , Hipotálamo/metabolismo , Osmorregulação/fisiologia , Ocitocina/metabolismo , Animais , Distrofina/metabolismo , Camundongos Knockout , NADPH Desidrogenase/metabolismo , Neurônios/metabolismo , Ocitocina/genética , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Supraóptico/metabolismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-30509920

RESUMO

The salinity of many freshwaters is increasing globally as a result of human activities. Associated with this increase in salinity are losses of Ephemeroptera (mayfly) abundance and richness. The salinity concentrations at which Ephemeroptera decline in nature are lower than their internal salinity or haemolymph osmolality. Many species also suffer substantial mortality in single species laboratory toxicity tests at salinities lower than their internal salinity. These findings are problematic as conventional osmoregulation theory suggests that freshwater animals should not experience stress where external osmolality is greater than haemolymph osmolality. Here I explore three hypotheses to explain salt sensitivity in Ephemeroptera. These conceptual hypotheses are based on the observations that as the external sodium ion (Na+) concentration increases so does the Na+ turnover rate (both uptake and elimination rates increase). Sulphate ([Formula: see text]) uptake in mayflies also increases with increasing external [Formula: see text] although, unlike Na+, its rate of increase decreases with increasing external [Formula: see text] The first hypothesis is premised on ion turnover being energetically costly. The first hypothesis proposes that individuals must devote a greater proportion of their energy to ion homeostasis at the expense of other uses including growth and development. Lethal levels of salinity presumably result from individuals not being able to devote enough energy to maintain ion homeostasis without critical loss of other vital functions. The second hypothesis is premised on the uptake of Na+ exchanged for (an outgoing) H+, leading to (localized) loss of pH regulation. The third hypothesis is premised on localized Na+ toxicity or poisoning with increased Na turnover as salinity increases. None of the proposed hypotheses is without potential problems, yet all are testable, and research effort should be focused at attempting to falsify them.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.


Assuntos
Ephemeroptera/fisiologia , Transporte de Íons/fisiologia , Osmorregulação/fisiologia , Salinidade , Sódio/metabolismo , Sulfatos/metabolismo , Animais , Água Doce/química
9.
PLoS One ; 13(10): e0206206, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30352080

RESUMO

Unique amongst the teleost, Plotosidae catfish possess a dendritic organ (DO) as a purported salt secreting organ, whereas other marine teleosts rely on their gill ionocytes for active NaCl excretion. To address the role of the DO in ionregulation, ligation experiments were conducted in brackish water (BW) 3‰ and seawater (SW) 34‰ acclimated Plotosus lineatus and compared to sham operated fish. Ligation in SW resulted in an osmoregulatory impairment in blood (elevated ions and hematocrit) and muscle (dehydration). However, SW ligation did not elicit compensatory changes in gill or kidney Na+/K+-ATPase (NKA) activity and/or protein expression while a decrease in anterior intestine and increased in posterior intestine were observed but this was not reflected at the protein level. Following ligation in SW, protein levels of carbonic anhydrase (CA) and V-ATPase B subunit (VHAB) were higher in kidney but either lower (CA) or unchanged (VHAB) in other tissues. Taken together, the osmotic disturbance in ligated SW fish indicates the central role of the DO in salt secretion and the absence of a compensatory response from the gill.


Assuntos
Estruturas Animais/fisiologia , Peixes-Gato/fisiologia , Osmorregulação/fisiologia , Pressão Osmótica/fisiologia , Aclimatação , Estruturas Animais/cirurgia , Animais , Peixes-Gato/cirurgia , Proteínas de Peixes/metabolismo , Brânquias/fisiologia , Ligadura/métodos , Águas Salinas/química , Salinidade , Água do Mar/química , Cloreto de Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Equilíbrio Hidroeletrolítico
10.
Artigo em Inglês | MEDLINE | ID: mdl-30374566

RESUMO

Silvering has been associated with advancing osmoregulatory ability. Given the demonstrated role of 11-ketotestosterone (11KT) in mediating many of the silvering-related changes, we investigated the role of 11KT in driving this advanced osmoregulatory ability in the New Zealand short-finned eel (Anguilla australis). Yellow (non-migratory) eels with or without 11KT implants and blank-implanted silver (migratory) eels, either held in freshwater or subjected to seawater challenge, were sampled to determine serum [Na+] and [Cl-], pituitary prolactin mRNA levels, gill Na+/K+-ATPase activity and gill mRNA levels for Na+/K+-ATPase-α1 subunit and for Na+/K+/2Cl- co-transporter-1α-subunit. Developmental stage and 11KT treatment advanced the eels' osmoregulatory ability. Thus, serum [Na+] and [Cl-] were affected by developmental stage and 11KT treatment upon seawater challenge. However, seawater challenge, not 11KT treatment or developmental stage, produced the strongest and the most consistent effects on A. australis osmoregulatory processes, inducing significant effects in all the relevant parameters we measured. In light of our results and in view of the eel's marine ancestry, we contend that A. australis, or freshwater eels in general, are highly tolerant and able to adapt quickly to changing salinities even at the yellow stage, which may preclude a critical need for an advanced osmoregulatory ability at silvering.


Assuntos
Anguilla/crescimento & desenvolvimento , Anguilla/metabolismo , Osmorregulação/fisiologia , Pigmentação , Testosterona/análogos & derivados , Animais , Cloretos/sangue , Feminino , Água Doce/química , Brânquias/metabolismo , Íons/sangue , Concentração Osmolar , Pigmentação/fisiologia , Hipófise/metabolismo , Prolactina/metabolismo , RNA Mensageiro/metabolismo , Água do Mar/química , Sódio/sangue , ATPase Trocadora de Sódio-Potássio/metabolismo , Testosterona/metabolismo
11.
Environ Microbiol Rep ; 10(6): 695-703, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30246403

RESUMO

Microbial species diversity may peak at certain optimal environmental conditions and decrease toward more extreme conditions. Indeed, bell-shaped relationships of species diversity against pH and temperature have been demonstrated, but diversity patterns across other environmental conditions are less well reported. In this study, we investigated the impact of salinity on the diversity of microorganisms from all three domains in a large set of natural springs with salinities ranging from freshwater to halite saturated. Habitat salinity was found to be linearly and inversely related to diversity of all three domains. The relationship was strongest in the bacteria, where salinity explained up to 44% of the variation in different diversity metrics (OTUs, Shannon index, and Phylogenetic Diversity). However, the relationship was weaker for Eukarya and Archaea. The known salt-in strategist Archaea of the Halobacteriaceae even showed the opposite trend, with increasing diversity at higher salinity. We propose that high energetic requirements constrain species diversity at high salinity but that the diversity of taxa with energetically less expensive osmotolerance strategies is less affected. Declining diversity with increasing osmotic stress may be a general rule for microbes as well as plants and animals, but the strength of this relationship varies greatly across microbial taxa.


Assuntos
Biodiversidade , Nascentes Naturais/microbiologia , Osmorregulação/fisiologia , Pressão Osmótica/fisiologia , Salinidade , Archaea/classificação , Archaea/genética , Archaea/fisiologia , Bactérias/classificação , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Eucariotos/classificação , Eucariotos/genética , Eucariotos/fisiologia , Microbiota/genética , Nascentes Naturais/química , RNA Ribossômico/genética , Cloreto de Sódio/metabolismo , Especificidade da Espécie
12.
Sci Total Environ ; 645: 1094-1102, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30248834

RESUMO

The demand for food with high nutritional value that can sustain the growth of human population while safeguarding sustainability deserves urgent attention. A possible strategy is the inoculation of crops with plant growth promoting (PGP) bacteria. Plants are naturally colonized by bacteria that can exert beneficial effects on growth and stress tolerance. N2 fixation by rhizobia in the root nodules of legumes is a well-known PGP effect. These bacteria can be used as inoculants to boost legumes productivity and can be especially interesting if they are able to survive to abiotic stresses, such as drought. Herein we report the phylogenetic diversity of bacteria colonizing the root nodules of several wild legume species, from four geographic locations in Portugal with different bioclimates. Interestingly, the vast majority of strains belonged to Flavobacterium, Pseudomonas and other genera apart from rhizobia. PGP abilities other than N2 fixation (production of indol acetic acid, siderophores and volatile organic compounds) and osmotolerance were screened. Location and host plant species did not influence PGP abilities and osmotolerance. Taken together, results evidenced that bacterial strains from wild legumes displaying PGP abilities and osmotolerance can be regarded as good candidates for inoculants of a broad range of hosts, including non-legumes.


Assuntos
Bactérias , Fabaceae/microbiologia , Fabaceae/crescimento & desenvolvimento , Fabaceae/fisiologia , Osmorregulação/fisiologia , Filogenia , Raízes de Plantas , Portugal , Rhizobium
13.
Biochim Biophys Acta Mol Basis Dis ; 1864(11): 3559-3573, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30251676

RESUMO

Mutations in CLN3 cause a juvenile form of neuronal ceroid lipofuscinosis (NCL), commonly known as Batten disease. Currently, there is no cure for NCL and the mechanisms underlying the disease are not well understood. In the social amoeba Dictyostelium discoideum, the CLN3 homolog, Cln3, localizes predominantly to the contractile vacuole (CV) system. This dynamic organelle functions in osmoregulation, and intriguingly, osmoregulatory defects have been observed in mammalian cell models of CLN3 disease. Therefore, we used Dictyostelium to further study the involvement of CLN3 in this conserved cellular process. First, we assessed the localization of GFP-Cln3 during mitosis and cytokinesis, where CV system function is essential. GFP-Cln3 localized to the CV system during mitosis and cln3- cells displayed defects in cytokinesis. The recovery of cln3- cells from hypotonic stress and their progression through multicellular development was delayed and these effects were exaggerated when cells were treated with ammonium chloride. In addition, Cln3-deficiency reduced the viability of cells during hypotonic stress and impaired the integrity of spores. During hypertonic stress, Cln3-deficiency reduced cell viability and inhibited development. We then performed RNA sequencing to gain insight into the molecular pathways underlying the sensitivity of cln3- cells to osmotic stress. This analysis revealed that cln3-deficiency upregulated the expression of tpp1A, the Dictyostelium homolog of human TPP1/CLN2. We used this information to show a correlated increase in Tpp1 enzymatic activity in cln3- cells. In total, our study provides new insight in the mechanisms underlying the role of CLN3 in osmoregulation and neurodegeneration.


Assuntos
Glicoproteínas de Membrana/metabolismo , Lipofuscinoses Ceroides Neuronais/patologia , Osmorregulação/fisiologia , Proteínas de Protozoários/metabolismo , Animais , Linhagem Celular , Dictyostelium , Modelos Animais de Doenças , Humanos , Glicoproteínas de Membrana/genética , Mitose/fisiologia , Lipofuscinoses Ceroides Neuronais/genética , Pressão Osmótica/fisiologia , Proteínas de Protozoários/genética , Vacúolos/metabolismo
14.
J Proteome Res ; 17(9): 3223-3236, 2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30085679

RESUMO

Fruits of Lycium ruthenicum (LR) and L. barbarum (LB) in Solanaceae family contain abundant bioactive metabolites used widely as functional food and natural medicine. To characterize the fruit developmental molecular phenotypes, we comprehensively analyzed metabolite composition of both Lycium fruits at three developmental stages using the combined NMR, liquid chromatography-tandem mass spectrometry, and gas chromatography-flame ionization detector/mass spectrometry methods. The metabonomes of these fruits were dominated by over 90 metabolites including sugars, amino acids, tricarboxylic acid (TCA) cycle intermediates, fatty acids, choline metabolites, and shikimate-mediated plant secondary metabolites. Metabolic phenotypes of two species differed significantly at all three developmental stages; LB fruits contained significantly more sugars and amino acids but less TCA cycle intermediates, fatty acids, and secondary metabolites than LR. Interspecies differences for fatty acid levels were much greater after color-breaking than precolor-breaking. Furthermore, LR fruits contained more osmolytes than LB fruits indicating different osmoregulation requirements for these fruits during development. Significant differences were also present in biosynthesis of shikimate-mediated plant secondary metabolites in LR and LB. These findings provided essential metabolic information for plant physiology of these  Lycium species and their utilizations demonstrating the usefulness of this metabonomic phenotyping approach for studying fundamental biochemistry of the plant development.


Assuntos
Frutas/metabolismo , Lycium/metabolismo , Metaboloma/fisiologia , Metabolômica/métodos , Metabolismo Secundário/fisiologia , Aminoácidos/isolamento & purificação , Aminoácidos/metabolismo , Colina/análogos & derivados , Colina/isolamento & purificação , Colina/metabolismo , Cromatografia Líquida , Ácidos Graxos/isolamento & purificação , Ácidos Graxos/metabolismo , Frutas/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Lycium/classificação , Lycium/crescimento & desenvolvimento , Espectroscopia de Ressonância Magnética , Metabolômica/instrumentação , Osmorregulação/fisiologia , Fenótipo , Ácido Chiquímico/isolamento & purificação , Ácido Chiquímico/metabolismo , Especificidade da Espécie , Açúcares/isolamento & purificação , Açúcares/metabolismo , Espectrometria de Massas em Tandem , Ácidos Tricarboxílicos/isolamento & purificação , Ácidos Tricarboxílicos/metabolismo
15.
Brain Behav Evol ; 91(3): 148-157, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30099462

RESUMO

When comparative neuromorphological studies are extended into evolutionary contexts, traits of interest are often linked to diversification patterns. Features demonstrably associated with increases in diversification rates and the infiltration or occupation of novel niche spaces are often termed "key innovations." Within the past decade, phylogenetically informed methods have been developed to test key innovation hypotheses and evaluate the influence these traits have had in shaping modern faunas. This is primarily accomplished by estimating state-dependent speciation and extinction rates. These methods have important caveats and guidelines related to both calculation and interpretation, which are necessary to understand in cases of discrete (qualitative) character analysis, as can be common when studying the evolution of neuromorphology. In such studies, inclusion of additional characters, acknowledgement of character codistribution, and addition of sister clade comparison should be explored to ensure model accuracy. Even so, phylogenies provide a survivor-only examination of character evolution, and paleontological contexts may be necessary to replicate and confirm results. Here, I review these issues in the context of selective brain cooling - a neurovascular-mediated osmoregulatory physiology that dampens hypothalamic responses to heat stress and reduces evaporative water loss in large-bodied mammals. This binary character provides an example of the interplay between sample size, evenness, and character codistribution. Moreover, it allows for an opportunity to compare phylogenetically constrained results with paleontological data, augmenting survivor-only analyses with observable extinction patterns. This trait- dependent diversification example indicates that selective brain cooling is significantly associated with the generation of modern large-mammal faunas. Importantly, paleontological data validate phylogenetic patterns and demonstrate how suites of characters worked in concert to establish the large-mammal communities of today.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Encéfalo/fisiologia , Fósseis , Osmorregulação/fisiologia , Filogenia , Animais , Encéfalo/irrigação sanguínea
16.
Fish Physiol Biochem ; 44(5): 1393-1408, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29923042

RESUMO

Gene expression of key ion transporters (the Na+/K+-ATPase NKA, the Na+, K+-2Cl- cotransporter NKCC1, and CFTR) in the gills, opercular inner epithelium, and pseudobranch of European seabass juveniles (Dicentrarchus labrax) were studied after acute transfer up to 4 days from seawater (SW) to freshwater (FW). The functional remodeling of these organs was also studied. Handling stress (SW to SW transfer) rapidly induced a transcript level decrease for the three ion transporters in the gills and operculum. NKA and CFTR relative expression level were stable, but in the pseudobranch, NKCC1 transcript levels increased (up to 2.4-fold). Transfer to FW induced even more organ-specific responses. In the gills, a 1.8-fold increase for NKA transcript levels occurs within 4 days post transfer with also a general decrease for CFTR and NKCC1. In the operculum, transcript levels are only slightly modified. In the pseudobranch, there is a transient NKCC1 increase followed by 0.6-fold decrease and 0.8-fold CFTR decrease. FW transfer also induced a density decrease for the opercular ionocytes and goblet cells. Therefore, gills and operculum display similar trends in SW-fish but have different responses in FW-transferred fish. Also, the pseudobranch presents contrasting response both in SW and in FW, most probably due to the high density of a cell type that is morphologically and functionally different compared to the typical gill-type ionocyte. This pseudobranch-type ionocyte could be involved in blood acid-base regulation masking a minor osmotic regulatory capacity of this organ compared to the gills.


Assuntos
Bass/metabolismo , Transporte de Íons/fisiologia , Aclimatação/genética , Aclimatação/fisiologia , Animais , Bass/anatomia & histologia , Bass/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Água Doce , Expressão Gênica , Transporte de Íons/genética , Osmorregulação/genética , Osmorregulação/fisiologia , Faringe/anatomia & histologia , Faringe/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Salinidade , Água do Mar , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/metabolismo , Membro 2 da Família 12 de Carreador de Soluto/genética , Membro 2 da Família 12 de Carreador de Soluto/metabolismo
17.
Physiology (Bethesda) ; 33(3): 170-181, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29616878

RESUMO

Mammals are characterized by a stable core body temperature. When maintenance of core temperature is challenged by ambient or internal heat loads, mammals increase blood flow to the skin, sweat and/or pant, or salivate. These thermoregulatory responses enable evaporative cooling at moist surfaces to dissipate body heat. If water losses incurred during evaporative cooling are not replaced, body fluid homeostasis is challenged. This article reviews the way mammals balance thermoregulation and osmoregulation.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Homeostase/fisiologia , Osmorregulação/fisiologia , Animais , Temperatura Corporal/fisiologia , Humanos , Equilíbrio Hidroeletrolítico/fisiologia
18.
PLoS Genet ; 14(4): e1007342, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29659565

RESUMO

Cyclic nucleotides are universally used as secondary messengers to control cellular physiology. Among these signalling molecules, cyclic di-adenosine monophosphate (c-di-AMP) is a specific bacterial second messenger recognized by host cells during infections and its synthesis is assumed to be necessary for bacterial growth by controlling a conserved and essential cellular function. In this study, we sought to identify the main c-di-AMP dependent pathway in Streptococcus agalactiae, the etiological agent of neonatal septicaemia and meningitis. By conditionally inactivating dacA, the only diadenyate cyclase gene, we confirm that c-di-AMP synthesis is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable due to the accumulation of compensatory mutations. We identified several mutations restoring the viability of a ΔdacA mutant, in particular a loss-of-function mutation in the osmoprotectant transporter BusAB. Identification of c-di-AMP binding proteins revealed a conserved set of potassium and osmolyte transporters, as well as the BusR transcriptional factor. We showed that BusR negatively regulates busAB transcription by direct binding to the busAB promoter. Loss of BusR repression leads to a toxic busAB expression in absence of c-di-AMP if osmoprotectants, such as glycine betaine, are present in the medium. In contrast, deletion of the gdpP c-di-AMP phosphodiesterase leads to hyperosmotic susceptibility, a phenotype dependent on a functional BusR. Taken together, we demonstrate that c-di-AMP is essential for osmotic homeostasis and that the predominant mechanism is dependent on the c-di-AMP binding transcriptional factor BusR. The regulation of osmotic homeostasis is likely the conserved and essential function of c-di-AMP, but each species has evolved specific c-di-AMP mechanisms of osmoregulation to adapt to its environment.


Assuntos
Fosfatos de Dinucleosídeos/metabolismo , Osmorregulação/fisiologia , Streptococcus agalactiae/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Genes Bacterianos , Homeostase/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Mutação , Osmorregulação/genética , Fósforo-Oxigênio Liases/genética , Fósforo-Oxigênio Liases/metabolismo , Potássio/metabolismo , Sistemas do Segundo Mensageiro/fisiologia , Streptococcus agalactiae/genética , Streptococcus agalactiae/crescimento & desenvolvimento
19.
Artigo em Inglês | MEDLINE | ID: mdl-29698766

RESUMO

Understanding the physiological responses of fishes to salinity changes and aquatic hypoxia is essential for the conservation of marine species. Salinity changes affect the osmotic gradient across the gill epithelium, while hypoxia increases gill ventilation and the flow of water over the gills. Both processes affect the diffusive movement of ions and water across the gill epithelium, and the rate of active ion transport required for maintaining osmotic homeostasis. Consequently, salinity and hypoxia may affect the energetic cost of osmoregulation, and consequently the energy available for other physiological functions such as migration, growth, and reproduction. Historically, studies have assessed the costs of osmoregulation and ventilation in fishes via standard metabolic rate (SMR); however, few studies have used a multi-stressor approach that fully accounts for the osmorespiratory compromise. Here, we determined the combined effects of salinity and hypoxia on SMR, routine metabolic rate (RMR), and plasma ion concentrations in red drum (Sciaenops ocellatus) acclimated to salinities ranging from freshwater to hypersalinity. Surprisingly, there was no significant change in any parameter as a consequence of salinity or hypoxia, including the relatively extreme scenario of combined hypersalinity and hypoxia exposure. We conclude that changes in the osmotic gradient across the gill epithelium and the flow of water over the gills have a negligible effect on the whole animal energy budget of S. ocellatus, suggesting that the cost of osmoregulation is a minor component of basal metabolism regardless of oxygenation status.


Assuntos
Peixes/fisiologia , Hiperventilação/fisiopatologia , Hipóxia/fisiopatologia , Osmorregulação/fisiologia , Consumo de Oxigênio/fisiologia , Salinidade , Aclimatação/fisiologia , Animais , Metabolismo Energético , Estuários , Peixes/metabolismo , Brânquias/fisiologia
20.
Neurobiol Aging ; 65: 178-191, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29494864

RESUMO

Elderly people exhibit a diminished capacity to cope with osmotic challenges such as dehydration. We have undertaken a detailed molecular analysis of arginine vasopressin (AVP) biosynthetic processes in the supraoptic nucleus (SON) of the hypothalamus and secretory activity in the posterior pituitary of adult (3 months) and aged (18 months) rats, to provide a comprehensive analysis of age-associated changes to the AVP system. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, we identified differences in pituitary peptides, including AVP, in adult and aged rats under both basal and dehydrated states. In the SON, increased Avp gene transcription, coincided with reduced Avp promoter methylation in aged rats. Based on transcriptome data, we have previously characterized a number of novel dehydration-induced regulatory factors involved in the response of the SON to osmotic cues. We found that some of these increase in expression with age, while dehydration-induced expression of these genes in the SON was attenuated in aged rats. In summary, we show that aging alters the rat AVP system at the genome, transcriptome, and peptidome levels. These alterations however did not affect circulating levels of AVP in basal or dehydrated states.


Assuntos
Envelhecimento/metabolismo , Arginina Vasopressina/biossíntese , Arginina Vasopressina/genética , Desidratação/genética , Desidratação/metabolismo , Sistemas Neurossecretores/metabolismo , Osmorregulação/fisiologia , Núcleo Supraóptico/metabolismo , Animais , Arginina Vasopressina/metabolismo , Genoma/genética , Masculino , Espectrometria de Massas/métodos , Metilação , Concentração Osmolar , Neuro-Hipófise/metabolismo , Regiões Promotoras Genéticas , Ratos Wistar , Transcrição Genética , Transcriptoma/genética
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