RESUMO
Environmental stressors in aquatic organisms can be assessed using a bioenergetic approach based on the evaluation of changes in their physiological parameters. We evaluated the chronic effects of cadmium (Cd2+) on the energy balance as well as the survival, growth, metabolism, nitrogen excretion, hepatosomatic index, oxidized energy substrate, and osmoregulation of the shrimp Penaeus vannamei with the hypothesis that the high energy demand related to the homeostatic regulation of Cd2+could disrupt the energy balance and as a consequence, their physiological functions. The shrimp exposed to Cd2+ had higher mortality (30%), directed more energy into growth (33% of energy intake), ingested 10% more energy, and defecated less than control animals. Cd2+ exposure caused a tendency to decrease metabolism and ammonia excretion but did not alter the hepatosomatic index, type of energy substrate oxidized, and the hyperosmorregulatory pattern of the species. The Cd+2 exposure may have induced a trade-off response because there was a growth rate increase accompanied by increased mortality.
Assuntos
Cádmio , Metabolismo Energético , Penaeidae , Poluentes Químicos da Água , Animais , Cádmio/toxicidade , Penaeidae/efeitos dos fármacos , Penaeidae/fisiologia , Penaeidae/crescimento & desenvolvimento , Poluentes Químicos da Água/toxicidade , Metabolismo Energético/efeitos dos fármacos , Osmorregulação/efeitos dos fármacosRESUMO
Soil deterioration is a major cause of poor agricultural productivity, necessitating sufficient nutrient inputs like fertilizers and amendments for sustainable use. As one such strategy, the current study evaluates the potential of Sargassum wightii, a brown seaweed extract, as an osmopriming agent to improve seed germination, early establishment, and competent seedling performances in acidic soil. The elemental makeup of seaweed extract (BS) showed that it included major plant macro (Potassium, Nitrogen and Phosphorous), as well as micronutrients (Magnesium and Iron) and trace elements (Zinc, Copper, and Molybdenum). While seed germination was impacted by H+ ion toxicity, seeds primed with BS emerged earlier and showed a higher germination percentage (98.2%) and energy (92.4%). BS treatments enhanced seedling growth by 63% and had a positive effect on root growth (68.2%) as well as increases in root surface area (10%) and volume (67.01%). Stressed seedlings had 76.39% and 63.2% less carotenoid and chlorophyll, respectively. In seedlings treated with BS, an increase in protein and Total Soluble Sugars content of 14.56 and 7.19%, respectively, was seen. Fourier Transform-Infra Red analysis of postharvest soil indicated improved soil health with absorbance corresponding to enhanced soil water holding capacity and organic matter. Increased abscisic acid synthesis rate and associated antioxidant enzyme system (Malondialdehyde, Glutathione peroxidases and ascorbate peroxidase) activation, along with enhanced H+ adenosine triphosphate-ase and glutathione activities, help ameliorate and deport H+ ions from cells, scavenge Reactive Oxygen Species, thus protecting cells from injury. Seaweed extract successfully reduced H+-induced ion toxicities in rice by promoting their germination, physiological, metabolically, and growth parameters that could ultimately increase their productivity and yield in a sustainable and environmentally friendly manner.
Assuntos
Ácido Abscísico , Germinação , Oryza , Raízes de Plantas , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Ácido Abscísico/metabolismo , Germinação/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Alga Marinha/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Poluentes do Solo/toxicidade , Metais/toxicidade , Osmorregulação/efeitos dos fármacosRESUMO
Semi-anadromous animals experience salinity fluctuations during their life-span period. Alterations of environmental conditions induce stress response where catecholamines (CA) play a central role. Physiological stress and changes in external and internal osmolarity are frequently associated with increased production of reactive oxygen species (ROS). In this work, we studied the involvement of the cAMP/PKA pathway in mediating catecholamine-dependent effects on osmoregulatory responses, intracellular production of ROS, and mitochondrial membrane potential of the river lamprey (Lampetra fluviatilis, Linnaeus, 1758) red blood cells (RBCs). We also investigated the role of hypoosmotic shock in the process of ROS production and mitochondrial respiration of RBCs. For this, osmotic stability and the dynamics of the regulatory volume decrease (RVD) following hypoosmotic swelling, intracellular ROS levels, and changes in mitochondrial membrane potential were assessed in RBCs treated with epinephrine (Epi, 25 µM) and forskolin (Forsk, 20 µM). Epi and Forsk markedly reduced the osmotic stability of the lamprey RBCs whereas did not affect the dynamics of the RVD response in a hypoosmotic environment. Activation of PKA with Epi and Forsk increased ROS levels and decreased mitochondrial membrane potential of the lamprey RBCs. In contrast, upon hypoosmotic shock enhanced ROS production in RBCs was accompanied by increased mitochondrial membrane potential. Overall, a decrease in RBC osmotic stability and the enhancement of ROS formation induced by ß-adrenergic stimulation raises concerns about stress-associated changes in RBC functions in agnathans. Increased ROS production in RBCs under hypoosmotic shock indicates that a decrease in blood osmolarity may be associated with oxidative damage of RBCs during lamprey migration.
Assuntos
Epinefrina , Eritrócitos , Lampreias , Potencial da Membrana Mitocondrial , Pressão Osmótica , Espécies Reativas de Oxigênio , Animais , Eritrócitos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Pressão Osmótica/efeitos dos fármacos , Lampreias/fisiologia , Epinefrina/farmacologia , Colforsina/farmacologia , Osmorregulação/efeitos dos fármacos , Proteínas Quinases Dependentes de AMP Cíclico/metabolismoRESUMO
In this study, the effects of exogenous methyl jasmonate (MeJA) on metal uptake and its ability to attenuate metal toxicity in kenaf plants under Pb stress were investigated. The experiment was conducted with five different MeJA concentrations (0, 40, 80, 160, and 320 µM) as a foilar application to kenaf plants exposed to 200 µM Pb stress. The results revealed that pretreatmen of MeJA significantly increased plant dry weight, plant height, and root architecture at all concentrations tested, with the most significant increase at 320 µM. Foliar application of MeJA at 160 µM and 320 µM increased the Pb concentrations in leaves and stems as well as the translocation factor (TF) from root to leaf. However, the bioaccumulation factor in the shoot initially decreased and then increased with increasing MeJA concentration. By increasing enzymatic (SOD, POD, and CAT) and non-enzymatic (AsA and non-protein thiols) antioxidants, MeJA pretreatment decreased lipid peroxidation, O2- and H2O2 accumulation and recovered photosynthetic pigment content under Pb stress. Increased osmolytes (proline, sugar, and starch) and protein content after MeJA pretreatment under Pb stress restore cellular homeostasis and improved kenaf tolerance. Our results suggest that MeJA pretreatment modifies the antioxidant machinery of kenaf and inhibits stress-related processes that cause lipid peroxidation, hence enhancing plant tolerance to Pb stress.
Assuntos
Acetatos , Antioxidantes , Ciclopentanos , Hibiscus , Chumbo , Oxilipinas , Antioxidantes/metabolismo , Chumbo/toxicidade , Osmorregulação/efeitos dos fármacosRESUMO
Keeping the significance of potassium (K) nutrition in focus, this study explores the genotypic responses of two wild Tibetan barley genotypes (drought tolerant XZ5 and drought sensitive XZ54) and one drought tolerant barley cv. Tadmor, under the exposure of polyethylene glycol-induced drought stress. The results revealed that drought and K deprivation attenuated overall plant growth in all the tested genotypes; however, XZ5 was least affected due to its ability to retain K in its tissues which could be attributed to the smallest reductions of photosynthetic parameters, relative chlorophyll contents and the lowest Na+/K+ ratios in all treatments. Our results also indicate that higher H+/K+-ATPase activity (enhancement of 1.6 and 1.3-fold for shoot; 1.4 and 2.5-fold for root), higher shoot K+ (2 and 2.3-fold) and Ca2+ content (1.5 and 1.7-fold), better maintenance of turgor pressure by osmolyte accumulation and enhanced antioxidative performance to scavenge ROS, ultimately suppress lipid peroxidation (in shoots: 4% and 35%; in roots 4% and 20% less) and bestow higher tolerance to XZ5 against drought stress in comparison with Tadmor and XZ54, respectively. Conclusively, this study adds further evidence to support the concept that Tibetan wild barley genotypes that utilize K efficiently could serve as a valuable genetic resource for the provision of genes for improved K metabolism in addition to those for combating drought stress, thereby enabling the development of elite barley lines better tolerant of abiotic stresses.
Assuntos
Antioxidantes/metabolismo , Hordeum/fisiologia , Proteínas de Plantas/genética , Potássio/metabolismo , Clorofila/metabolismo , Secas , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genótipo , Hordeum/efeitos dos fármacos , Hordeum/genética , Peroxidação de Lipídeos/efeitos dos fármacos , Osmorregulação/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Polietilenoglicóis/efeitos adversos , Metabolismo Secundário/efeitos dos fármacos , Sódio/metabolismo , TibetRESUMO
The aim of present study was synthesize 6-(2-hydroxyethyl)cyclohex-3-enol (11) and investigate its antioxidant properties in barley plants under drought stress. For this aim, 1,4-cyclohexadiene (7) was subjected to [2 + 2] ketene addition reaction with dichloro ketene and the chlorine atoms were reduced. After that, the cyclobutanone ring was converted to a lactone ring and the lactone ring was reduced with LiAlH4. Subsequently, 6-(2-hydroxyethyl)cyclohex-3-enol (13) was obtained with high yield. The structures of the synthesized molecules were clarified by NMR, FTIR, GCMS spectroscopic methods. Two different methods were used to evaluate antioxidant activity of cyclohexenediol 11. One of them was DPPH radical scavenging activity which was used extensively. Also, osmoprotectant and antioxidant effects of 6-(2-hydroxyethyl)cyclohex-3-enol (13) were investigated in barley under drought stress. Drought decreased the relative water content (RWC) and water potential (WP) in barley leaves. Cyclohexenediol 11 treatment remarkably increased RWC and WP in leaves under drought conditions. Superoxide [Formula: see text] and nitric oxide (NO) accumulated under drought. In cyclohexenediol 11 treated-plants, the accumulation [Formula: see text] and NO were strongly reduced under drought conditions. Our results showed that cyclohexenediol 11 helped barley plants for maintaining water under drought stress; this makes synthetic cyclitol cyclohexenediol 11 as a good osmoprotectant candidate. Another important result in this study was the strong radical scavenging potential of cyclohexenediol 11. We think that much more comprehensive biochemical studies should be conducted to determine how cyclohexenediol 11 performs the radical scavenge role.
Assuntos
Antioxidantes/farmacologia , Hordeum/efeitos dos fármacos , Osmorregulação/efeitos dos fármacos , Antioxidantes/metabolismo , Secas/mortalidade , Secas/estatística & dados numéricos , Hordeum/metabolismo , Fatores de Proteção , Estresse Fisiológico/efeitos dos fármacosRESUMO
Tris (2-chloroethyl) phosphate (TCEP) is an emerging aquatic environmental pollutant. In the present study, juvenile yellow catfish (Pelteobagrus fulvidraco) were exposed to environmentally relevant concentrations of TCEP for 30 days. The results showed that TCEP exposure decreased the survival rate (100 µg/L), body weight (10 and 100 µg/L) and specific growth rate (10 and 100 µg/L) of juvenile yellow catfish. Exposure to TCEP resulted in pronounced damages of gill structures. Gene transcription analysis showed that the antioxidant capacity of the liver and gills was affected; CYP1A1 might contribute to phase I metabolism of TCEP in the liver rather than CYP1B1; TCEP stress might increase the demand of ion transport in fish gill; TCEP could stimulate the immune response and might induce apoptosis via a p53-Bax pathway and caspase-dependent pathway in gills. Collectively, these findings provide new insights into the toxic effects of TCEP on fish.
Assuntos
Peixes-Gato , Retardadores de Chama/toxicidade , Organofosfatos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Peixes-Gato/genética , Peixes-Gato/crescimento & desenvolvimento , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1B1/genética , Proteínas de Peixes/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Brânquias/patologia , Glutationa Transferase/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Osmorregulação/efeitos dos fármacos , Osmorregulação/genética , Oxirredutases/genéticaRESUMO
Taurine, a sulfur-containing amino acid derivative, exists at a high concentration in the skin and is considered to play an important role in maintaining moisture homeostasis. This study investigated the effects of oral taurine supplementation on epidermal moisture content and wrinkle formation, as well as skin taurine content, using ultraviolet B (UVB)-irradiated hairless mice. Wrinkles were induced by exposing hairless mice to UVB radiation (70-100 mJ/cm2). Taurine was dissolved in drinking water at a concentration of 0.3 or 3% (w/v) and given to the mice ad libitum for 2-10 weeks. Taurine was then extracted from the dorsal skin, and the skin taurine content was determined using high-performance liquid chromatography (HPLC). The wrinkles were evaluated using a wrinkle score and the quantitative wrinkle area ratio. The exposure of the mice to UVB radiation for 4 weeks resulted in a decreased moisture content and increased transepidermal water loss (TEWL) in the skin, while taurine supplementation suppressed these changes. Oral supplementation with taurine for 8 weeks ameliorated the development of UVB-induced wrinkle formation. Furthermore, oral taurine supplementation for 4 weeks decreased pre-stablished wrinkles in a dose-dependent manner. Although the UVB radiation reduced the epidermal taurine content, oral taurine supplementation partly restored the taurine content in the epidermis. The present study showed that oral taurine supplementation is able to suppress UVB-induced wrinkle formation, which may be associated with the regulation of moisture content in the epidermis. The beneficial effects of taurine on skin aging may be attributed to its osmoregulatory role.
Assuntos
Protetores contra Radiação/uso terapêutico , Envelhecimento da Pele/efeitos dos fármacos , Envelhecimento da Pele/efeitos da radiação , Taurina/uso terapêutico , Raios Ultravioleta , Animais , Suplementos Nutricionais , Epiderme/efeitos dos fármacos , Epiderme/efeitos da radiação , Masculino , Camundongos , Camundongos Pelados , Osmorregulação/efeitos dos fármacos , Taurina/metabolismo , Perda Insensível de Água/efeitos dos fármacos , Perda Insensível de Água/efeitos da radiaçãoRESUMO
Glucagon-like peptide-1 (GLP-1), a product of partial proteolysis of proglucagon, is involved not only in regulation of carbohydrates, but also in water-salt metabolism. The study examined the role of proglucagon derivatives GLP-1, GLP-2, and oxyntomodulin in rat osmoregulation. Of them, only blood plasma GLP-1 increased in response to water load (20 ml/kg). Administration of glucose (1.5 g/kg) elevated GLP-1 and oxyntomodulin but did not change the level of GLP-2. GLP-1 accelerated excretion of excess water during hyperhydration, whereas GLP-2 decreased this parameter. No physiological effects of oxyntomodulin in the kidneys were revealed. Probably, the blood levels of proglucagon derivatives are independently regulated for each peptide. In contrast to GLP-2 and oxyntomodulin, GLP-1 is involved in osmoregulation.
Assuntos
Peptídeos/farmacologia , Proglucagon/farmacologia , Animais , Feminino , Peptídeo 1 Semelhante ao Glucagon/química , Peptídeo 2 Semelhante ao Glucagon/química , Rim/efeitos dos fármacos , Rim/metabolismo , Osmorregulação/efeitos dos fármacos , Peptídeos/química , Proglucagon/química , Ratos , Ratos WistarRESUMO
Hyperosmotic stresses represent some of the most serious abiotic factors that adversely affect plants growth, development and fitness. Despite their central role, the early cellular events that lead to plant adaptive responses remain largely unknown. In this study, using Arabidopsis thaliana cultured cells we analyzed early cellular responses to sorbitol-induced hyperosmotic stress. We observed biphasic and dual responses of A. thaliana cultured cells to sorbitol-induced hyperosmotic stress. A first set of events, namely singlet oxygen (1O2) production and cell hyperpolarization due to a decrease in anion channel activity could participate to signaling and osmotic adjustment allowing cell adaptation and survival. A second set of events, namely superoxide anion (O2-) production by RBOHD-NADPH-oxidases and SLAC1 anion channel activation could participate in programmed cell death (PCD) of a part of the cell population. This set of events raises the question of how a survival pathway and a death pathway could be induced by the same hyperosmotic condition and what could be the meaning of the induction of two different behaviors in response to hyperosmotic stress.
Assuntos
Apoptose/efeitos dos fármacos , Arabidopsis/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Osmorregulação/efeitos dos fármacos , Pressão Osmótica/efeitos dos fármacos , Sorbitol/metabolismoRESUMO
We analyzed the modulation by exogenous FXYD2 peptide and by endogenous protein kinases A and C, and Ca2+-calmodulin-dependent kinase, of gill (Na+, K+)-ATPase activity in the semi-terrestrial mangrove crab Ucides cordatus after 10-days acclimation to different salinities. Osmotic and ionic regulatory ability and gill (Na+, K+)-ATPase activity also were evaluated. (Na+, K+)-ATPase activity is stimulated by exogenous pig kidney FXYD2 peptide, while phosphorylation by endogenous protein kinases A and C and Ca2+/calmodulin-dependent kinase inhibits activity. Stimulation by FXYD2 and inhibition by protein kinase C and Ca2+/calmodulin-dependent kinase are salinity-dependent. This is the first demonstration of inhibitory phosphorylation of a crustacean (Na+, K+)-ATPase by Ca2+/calmodulin-dependent kinase. At low salinities, the (Na+, K+)-ATPase exhibited a single, low affinity ATP-binding site that showed Michaelis-Menten behavior. Above 18S, a second, cooperative, high affinity ATP-binding site appeared, corresponding to 10-20% of total (Na+, K+)-ATPase activity. Hemolymph osmolality was strongly hyper-/hypo-regulated in crabs acclimated at 2 to 35S. Cl- was well hyper-/hypo-regulated although Na+ much less so, becoming isonatremic at elevated salinity. (Na+, K+)-ATPase activity was greatest in isosmotic crabs (26S), decreasing notably at 35S and also diminishing progressively from 18to 2S. Hyper-osmoregulation in U. cordatus showed little dependence on gill (Na+, K+)-ATPase activity, suggesting a role for other ion transporters. These findings reveal that the salinity acclimation response in U. cordatus consists of a suite of enzymatic and osmoregulatory adjustments that maintain its osmotic homeostasis in a challenging, mangrove forest environment.
Assuntos
Braquiúros/metabolismo , Oligopeptídeos/farmacologia , Osmorregulação/efeitos dos fármacos , Proteínas Quinases/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Aclimatação/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Braquiúros/fisiologia , Feminino , Hemolinfa/efeitos dos fármacos , Hemolinfa/metabolismo , Masculino , Oligopeptídeos/química , Concentração Osmolar , Fosforilação/efeitos dos fármacos , Salinidade , SuínosRESUMO
Diazinon is one of the insecticides that represent a high risk for Costa Rican estuarine environments due to its widespread use in pineapple plantations. In estuaries, organisms are frequently submitted to stress caused by natural factors (e.g., continuous changes in salinity levels) and, additionally, to stress due to contamination. Therefore, the driving question of this study was: will organisms be more susceptible to suffer the deleterious effects caused by diazinon because of the stress resulting from the salinity changes? The estuarine shrimp Penaeus vannamei was used as the model organism and two responses were measured: osmoregulation (the physiological effect after a forced and continuous 24 h-exposure) and avoidance [the behavioural effect after a short (3 h) non-forced, multi-compartmented exposure]. Juveniles were exposed to diazinon (0.1, 1, 10 and 100 µg/L) at three different salinities (10, 20 and 30). Disruption in the capacity to regulate the haemolymph osmotic pressure was observed at a salinity of 30 in individuals exposed to diazinon and methanol (used as vehicle). At that salinity, the ability of shrimps to detect and avoid the highest diazinon concentrations was impaired. P. vannamei juveniles inhabit environments with a high variation in salinity, but with an optimum osmotic point close to a salinity of 20; therefore, the higher the salinity, the greater the vulnerability of shrimps to the effects of diazinon. From an ecological point of view, this combined effect of salinity and contamination might also limit the spatial distribution of the organisms.
Assuntos
Diazinon/toxicidade , Reação de Fuga/efeitos dos fármacos , Inseticidas/toxicidade , Osmorregulação/efeitos dos fármacos , Penaeidae/fisiologia , Animais , Estuários , Hemolinfa/efeitos dos fármacos , Hemolinfa/metabolismo , Penaeidae/efeitos dos fármacos , Penaeidae/metabolismo , Salinidade , Poluentes Químicos da Água/toxicidadeRESUMO
In fishes, prolactin (Prl) signaling underlies the homeostatic regulation of hydromineral balance by controlling essential solute and water transporting functions performed by the gill, gastrointestinal tract, kidney, urinary bladder, and integument. Comparative studies spanning over 60 years have firmly established that Prl promotes physiological activities that enable euryhaline and stenohaline teleosts to reside in freshwater environments; nonetheless, the specific molecular and cellular targets of Prl in ion- and water-transporting tissues are still being resolved. In this short review, we discuss how particular targets of Prl (e.g., ion cotransporters, tight-junction proteins, and ion pumps) confer adaptive functions to the esophagus and intestine. Additionally, in some instances, Prl promotes histological and functional transformations within esophageal and intestinal epithelia by regulating cell proliferation. Collectively, the demonstrated actions of Prl in the gastrointestinal tract of teleosts indicate that Prl operates to promote phenotypes supportive of freshwater acclimation and to inhibit phenotypes associated with seawater acclimation. We conclude our review by underscoring that future investigations are warranted to determine how growth hormone/Prl-family signaling evolved in basal fishes to support the gastrointestinal processes underlying hydromineral balance.
Assuntos
Peixes/fisiologia , Trato Gastrointestinal/fisiologia , Osmorregulação , Prolactina/farmacologia , Animais , Cálcio/metabolismo , Trato Gastrointestinal/efeitos dos fármacos , Absorção Intestinal/efeitos dos fármacos , Osmorregulação/efeitos dos fármacosRESUMO
It is unknown whether and how osmoregulation is controlled by corticosteroid signaling in the phylogenetically basal vertebrate group Agnatha, including lampreys and hagfishes. It is known that a truncated steroid biosynthetic pathway in lampreys produces two predominant circulating corticosteroids, 11-deoxycortisol (S) and 11-deoxycorticosterone (DOC). Furthermore, lampreys express only a single, ancestral corticosteroid receptor (CR). Whether S and/or DOC interact with the CR to control osmoregulation in lampreys is still unknown. We examined the role of the endogenous corticosteroids in vivo and ex vivo in sea lamprey (Petromyzon marinus) during the critical metamorphic period during which sea lamprey increase osmoregulatory capacity and acquire seawater (SW) tolerance. We demonstrate in vivo that increases in circulating [S] and gill CR abundance are associated with increases in osmoregulatory capacity during metamorphosis. We further show that in vivo and ex vivo treatment with S increases activity and expression of gill active ion transporters and improves SW tolerance, and that only S (and not DOC) has regulatory control over active ion transport in the gills. Lastly, we show that the lamprey CR expresses an ancestral, spironolactone-as-agonist structural motif and that spironolactone treatment in vivo increases osmoregulatory capacity. Together, these results demonstrate that S is an osmoregulatory hormone in lamprey and that receptor-mediated discriminative corticosteroid regulation of hydromineral balance is an evolutionarily basal trait among vertebrates.
Assuntos
Cortodoxona/farmacologia , Osmorregulação/efeitos dos fármacos , Petromyzon/fisiologia , Animais , Cortodoxona/sangue , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Transporte de Íons , Metamorfose Biológica , Filogenia , Receptores de Esteroides/classificação , Receptores de Esteroides/metabolismo , Água do Mar/química , ATPase Trocadora de Sódio-Potássio/metabolismo , Equilíbrio HidroeletrolíticoRESUMO
Melon is of great value in food, medicine and industry. In recent years, the continuous cropping obstacles of melon is increasingly prominent, which seriously affects the cultivation. Autotoxicity is the key factor for the obstacles. Root is the first line against autotoxicity and main organs for autotoxins secretion. Some physiological responses and differentially expressed genes (DEGs) related to autotoxicity are only limited to root system. Considering the lack of relevant research, physiological researches combined with transcriptome sequencing of melon seedling after autotoxicity stress mediated by root exudates (RE) was performed to help characterize the response mechanism to autotoxicity in melon roots. The results showed that autotoxicity inhibited root morphogenesis of melon seedlings, induced the excessive accumulation of reactive oxygen species (ROS) and lipid peroxidation in roots, and activated most antioxidant enzymes. Compared with the control group, the osmoregulation substance content was always at a high level. DEGs response to autotoxicity in roots were distinguished from that in leaves. Functional annotation of these DEGs suggested that autotoxicity affected biological regulation in a negative manner. DEGs were mainly involved in the synthesis of antioxidants, DNA damage and metabolism, and stress response. These setbacks were associated with the deterioration of root morphogenesis, generation of dwarf and slender roots, and ultimately leading to plant death. The results may provide important information for revealing the response mechanism of root to autotoxicity, and provide theoretical basis for solving the continuous cropping obstacles in melon.
Assuntos
Produção Agrícola/métodos , Cucumis melo/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Transcriptoma/efeitos dos fármacos , Cucumis melo/genética , Cucumis melo/metabolismo , Perfilação da Expressão Gênica , Peroxidação de Lipídeos/efeitos dos fármacos , Osmorregulação/efeitos dos fármacos , Estresse Oxidativo/genética , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/metabolismoRESUMO
This paper reports the role of exogenous glycine betaine (25 and 50â¯mMâ¯GB at a rate of 50â¯mL per plant) in enhancing NaCl-stress tolerance in common bean (Phaseolus vulgaris L.). Irrigating plants by simulated saline water, containing 0, 50 and 100â¯mM sodium chloride (NaCl), significantly reduced the growth dynamics, photosynthetic pigments (i.e., Chl a, Chl b, and carotenoids), membrane stability index (MSI), relative water content (RWC), and pod yield. While, malondialdehyde (MDA), endogenous proline, and glutathione contents, electrolyte leakage (EL), antioxidant defense system, and Na+ accumulation markedly increased upon exposure to NaCl-stress. However, the application of exogenous GB significantly improved salt tolerance of common bean as it increased the antioxidant defense including both enzymatic (i.e., peroxidase, superoxide dismutase, and catalase) and nonenzymatic (i.e., proline and glutathione) agents. Consequently, MSI, RWC, EL, and photosynthetic pigments have been improved recording significantly higher values than the control. Moreover, the pod yield increased by 29.8 and 59.4% when plants grown under 50 and 100â¯mM NaCl, respectively, were sprayed with 25â¯mMâ¯GB. Our results show that GB-induced slat tolerance in common bean plants mainly depends on the osmoregulation effect of GB and to a lesser extent on its antioxidant capacity. Foliar application of GB significantly reduced the accumulation of Na+ and at the same time induced K+ uptake maintaining a higher K+/Na+ ratio. Despite some changes in the activities of antioxidant enzymes induced by the application of GB, no consistent contribution in the salt tolerance could be cited in this study. Therefore, we suggest that salt tolerance is largely unrelated to the antioxidant defense ability of GB in common bean. While the potential role of GB in ameliorating salt tolerance is mainly due to the adjustment of ions uptake through limiting Na+ uptake and alternatively increasing K+ accumulation in plant tissues.
Assuntos
Betaína/farmacologia , Phaseolus/efeitos dos fármacos , Potássio/metabolismo , Tolerância ao Sal , Sódio/metabolismo , Antioxidantes/metabolismo , Transporte Biológico/efeitos dos fármacos , Catalase/metabolismo , Cátions , Glutationa/metabolismo , Malondialdeído/análise , Osmorregulação/efeitos dos fármacos , Peroxidase/metabolismo , Phaseolus/química , Phaseolus/enzimologia , Phaseolus/metabolismo , Fotossíntese/efeitos dos fármacos , Potássio/análise , Prolina/metabolismo , Sódio/análise , Superóxido Dismutase/metabolismoRESUMO
We examined copper accumulation in the hemolymph, gills and hepatopancreas, and hemolymph osmolality, Na+ and Cl- concentrations, together with gill Na+/K+-ATPase and carbonic anhydrase activities, after dietary copper delivery (0, 100 or 500 Cu µg g-1) for 12 days in a fiddler crab, Minuca rapax. In contaminated crabs, copper concentration decreased in the hemolymph and hepatopancreas, but increased in the gills. Hemolymph osmolality and gill Na+/K+-ATPase activity increased while hemolymph [Na+] and [Cl-] and gill carbonic anhydrase activity decreased. Excretion likely accounts for the decreased hemolymph and hepatopancreas copper titers. Dietary copper clearly affected osmoregulatory ability and hemolymph Na+ and Cl- regulation in M. rapax. Gill copper accumulation decreased carbonic anhydrase activity, suggesting that dietary copper affects acid-base balance. Elevated gill Na+/K+-ATPase activity appears to compensate for the ion-regulatory disturbance. These effects of dietary copper illustrate likely impacts on semi-terrestrial species that feed on metal-contaminated sediments.
Assuntos
Bioacumulação , Braquiúros/efeitos dos fármacos , Cobre/metabolismo , Osmorregulação/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo , Animais , Braquiúros/metabolismo , Cobre/análise , Exposição Dietética , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Hemolinfa/metabolismo , Hepatopâncreas/metabolismo , Transporte de Íons , Concentração Osmolar , Alimentos Marinhos , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/análiseRESUMO
The human and animal osmoregulation system is aimed at stabilizing serum osmolality in order to maintain cell volume. It has been shown that the introduction of 5 mL water per 100 g of body weight into the stomach of rats decreases serum osmolality and the concentration of Na and Ca, but not K and Mg. The cascade system of osmotic homeostasis increases secretion of glucagon-like peptide-1 (GLP-1) and oxytocin, and decreases secretion of vasopressin, which reduces the osmotic permeability of collecting duct. After water loading and the injection of 0.015 nM exenatide (GLP-1 mimetic), the time of excretion of 50% of water was halved from 112 ± 4 to 57 ± 5 min (p < 0.01), and after the injection of 0.015 nM oxytocin, it decreased to 83 ± 6 min (p < 0.01). The physiological mechanism of renal effect of the aforementioned hormones which accelerate the recovery of osmotic homeostasis has been found.
Assuntos
Peptídeo 1 Semelhante ao Glucagon/sangue , Osmorregulação/fisiologia , Animais , Cálcio/sangue , Ingestão de Líquidos , Exenatida/farmacologia , Osmorregulação/efeitos dos fármacos , Ocitocina/farmacologia , Ocitocina/urina , Potássio/sangue , Ratos Wistar , Sódio/sangueRESUMO
Lyso-lipid acyltransferases are enzymes involved in various processes such as lipid synthesis and remodelling. Here, we characterized the activity of an acyltransferase from Arabidopsis thaliana (LPIAT). In vitro, this protein, expressed in Escherichia coli membrane, displayed a 2-lyso-phosphatidylinositol acyltransferase activity with a specificity towards saturated long chain acyl CoAs (C16:0- and C18:0-CoAs), allowing the remodelling of phosphatidylinositol. In planta, LPIAT gene was expressed in mature seeds and very transiently during seed imbibition, mostly in aleurone-like layer cells. Whereas the disruption of this gene did not alter the lipid composition of seed, its overexpression in leaves promoted a strong increase in the phosphatidylinositol phosphates (PIP) level without affecting the PIP2 content. The spatial and temporal narrow expression of this gene as well as the modification of PIP metabolism led us to investigate its role in the control of seed germination. Seeds from the lpiat mutant germinated faster and were less sensitive to abscisic acid (ABA) than wild-type or overexpressing lines. We also showed that the protective effect of ABA on young seedlings against dryness was reduced for lpiat line. In addition, germination of lpiat mutant seeds was more sensitive to hyperosmotic stress. All these results suggest a link between phosphoinositides and ABA signalling in the control of seed germination.
Assuntos
Aciltransferases/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Germinação , Osmorregulação , Fosfatos de Fosfatidilinositol/metabolismo , Sementes/crescimento & desenvolvimento , Transdução de Sinais , Ácido Abscísico/farmacologia , Acil Coenzima A/metabolismo , Arabidopsis/efeitos dos fármacos , Germinação/efeitos dos fármacos , Hipocótilo/efeitos dos fármacos , Hipocótilo/crescimento & desenvolvimento , Mutação/genética , Osmorregulação/efeitos dos fármacos , Fenótipo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Salinidade , Sementes/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
Polybrominated diphenyl ethers (PBDEs) are persistent environmental pollutants considered as neurotoxicants and endocrine disruptors with important biological effects ranging from alterations in growth, reproduction, and effects on the hypothalamus-pituitary-adrenal axis. The vasopressinergic (AVPergic) system is a known target for pentaBDEs mixture (DE-71) and the structurally similar chemicals, polychlorinated biphenyls. However, the potential adverse effects of mixtures containing octaBDE compounds, like DE-79, on the AVPergic system are still unknown. The present study aims to examine the effects of perinatal DE-79 exposure on the AVPergic system. Dams were dosed from gestational day 6 to postnatal day 21 at doses of 0 (control), 1.7 (low) or 10.2 (high) mg/kg/day, and male offspring from all doses at 3-months-old were subjected to normosmotic and hyperosmotic challenge. Male offspring where later assessed for alterations in osmoregulation (i.e. serum osmolality and systemic vasopressin release), and both vasopressin immunoreactivity (AVP-IR) and gene expression in the hypothalamic paraventricular and supraoptic nuclei. Additionally, to elucidate a possible mechanism for the effects of DE-79 on the AVPergic system, both neuronal nitric oxide synthase immunoreactivity (nNOS-IR) and mRNA expression were investigated in the same hypothalamic nuclei. The results showed that perinatal DE-79 exposure AVP-IR, mRNA expression and systemic release in adulthood under normosmotic conditions and more evidently under hyperosmotic stimulation. nNOS-IR and mRNA expression were also affected in the same nuclei. Since NO is an AVP regulator, we propose that disturbances in NO could be a mechanism underlying the AVPergic system disruption following perinatal DE-79 exposure leading to osmoregulation deficits.