RESUMEN

Osmoregulation, the physiological regulation of water and ion balance, is vital for the survival of both aquatic and terrestrial insects. In freshwater aquatic insects, such as those within the Lampyridae family, this function is important due to the natural variation of aquatic habitats. Aquaporins play a key role in this process by facilitating the rapid transport of water molecules across cell membranes, maintaining cellular water balance, and adapting to changes in external salinity. In this study, I investigate the genetic diversity and expression levels of aquaporins in Elateroidea, particularly focusing on the Lampyridae family, using transcriptomic data and in silico analyses. The results reveal the diversity of aquaporins and compare gene expression patterns between freshwater aquatic Lampyridae and terrestrial Elateroidea species, such as Lycidae, Phengodidae, and Elateridae. Phylogenetic analyses identify seven distinct clades of aquaporins and uncovered gene duplication events related to the diversification of Elateridae and Lampyridae. A comparative abundance analysis indicated higher aquaporin expression in aquatic fireflies, aligning with the need for efficient osmoregulation in aquatic environments. Additionally, stage-specific expression patterns in Aspisoma lineatum (Neotropical firefly) and Aquatica lateralis (Paleartic firefly) suggest species-specific strategies for coping with osmotic challenges during development. This study provides insights into the evolutionary adaptations of aquaporins in Elateroidea, highlighting their importance in both aquatic and terrestrial insect physiology.

Asunto(s)

Acuaporinas , Filogenia , Animales , Acuaporinas/genética , Acuaporinas/metabolismo , RNA-Seq , Transcriptoma , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Osmorregulación/genética , Variación Genética , Insectos/genética , Insectos/metabolismo

RESUMEN

Decapod Crustacea exhibit a marine origin, but many taxa have occupied environments ranging from brackish to fresh water and terrestrial habitats, overcoming their inherent osmotic challenges. Osmotic and ionic regulation is achieved by the gill epithelia, driven by two active ATP-hydrolyzing ion transporters, the basal (Na+, K+)-ATPase and the apical V(H+)-ATPase. The kinetic characteristic of gill (Na+, K+)-ATPase and the mRNA expression of its α subunit have been widely studied in various decapod species under different salinity challenges. However, the evolution of the primary structure has not been explored, especially considering the functional modifications associated with decapod phylogeny. Here, we proposed a model for the topology of the decapod α subunit, identifying the sites and motifs involved in its function and regulation, as well as the patterns of its evolution assuming a decapod phylogeny. We also examined both the amino acid substitutions and their functional implications within the context of biochemical and physiological adaptation. The α-subunit of decapod crustaceans shows greater conservation (∼94% identity) compared to the ß-subunit (∼40%). While the binding sites for ATP and modulators are conserved in the decapod enzyme, the residues involved in the α-ß interaction are only partially conserved. In the phylogenetic context of the complete sequence of (Na+, K+)-ATPase α-subunit, most substitutions appear to be characteristic of the entire group, with specific changes for different subgroups, especially among brachyuran crabs. Interestingly, there was no consistent separation of α-subunit partial sequences related to habitat, suggesting that the convergent evolution for freshwater or terrestrial modes of life is not correlated with similar changes in the enzyme's primary amino acid sequence.

Asunto(s)

Secuencia de Aminoácidos , Decápodos , Osmorregulación , Filogenia , ATPasa Intercambiadora de Sodio-Potasio , Animales , ATPasa Intercambiadora de Sodio-Potasio/genética , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/química , Osmorregulación/genética , Decápodos/genética , Decápodos/enzimología , Decápodos/fisiología , Evolución Molecular , Branquias/metabolismo , Branquias/enzimología

RESUMEN

In Escherichia coli, the disaccharide trehalose can be metabolized as a carbon source or be accumulated as an osmoprotectant under osmotic stress. In hypertonic environments, E. coli accumulates trehalose in the cell by synthesis from glucose mediated by the cytosolic enzymes OtsA and OtsB. Trehalose in the periplasm can be hydrolyzed into glucose by the periplasmic trehalase TreA. We have previously shown that a treA mutant of extraintestinal E. coli strain BEN2908 displayed increased resistance to osmotic stress by 0.6 M urea, and reduced production of type 1 fimbriae, reduced invasion of avian fibroblasts, and decreased bladder colonization in a murine model of urinary tract infection. Since loss of TreA likely results in higher periplasmic trehalose concentrations, we wondered if deletion of otsA and otsB genes, which would lead to decreased internal trehalose concentrations, would reduce resistance to stress by 0.6 M urea and promote type 1 fimbriae production. The BEN2908ΔotsBA mutant was sensitive to osmotic stress by urea, but displayed an even more pronounced reduction in production of type 1 fimbriae, with the consequent reduction in adhesion/invasion of avian fibroblasts and reduced bladder colonization in the murine urinary tract. The BEN2908ΔtreAotsBA mutant also showed a reduction in production of type 1 fimbriae, but in contrast to the ΔotsBA mutant, resisted better than the wild type in the presence of urea. We hypothesize that, in BEN2908, resistance to stress by urea would depend on the levels of periplasmic trehalose, but type 1 fimbriae production would be influenced by the levels of cytosolic trehalose.

Asunto(s)

Fimbrias Bacterianas , Osmorregulación , Trehalosa , Vejiga Urinaria , Infecciones Urinarias , Animales , Trehalosa/metabolismo , Ratones , Vejiga Urinaria/microbiología , Fimbrias Bacterianas/metabolismo , Fimbrias Bacterianas/genética , Infecciones Urinarias/microbiología , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Escherichia coli/metabolismo , Escherichia coli/genética , Modelos Animales de Enfermedad , Femenino , Presión Osmótica , Escherichia coli Patógena Extraintestinal/metabolismo , Escherichia coli Patógena Extraintestinal/genética , Urea/metabolismo , Trehalasa/metabolismo , Trehalasa/genética , Eliminación de Gen , Glucosa/metabolismo

RESUMEN

Trypanosoma cruzi uses various mechanisms to cope with osmotic fluctuations during infection, including the remodeling of organelles such as the contractile vacuole complex (CVC). Little is known about the morphological changes of the CVC during pulsation cycles occurring upon osmotic stress. Here, we investigated the structure-function relationship between the CVC and the flagellar pocket domain where fluid discharge takes place-the adhesion plaque-during the CVC pulsation cycle. Using TcrPDEC2 and TcVps34 overexpressing mutants, known to have low and high efficiency for osmotic responses, we described a structural phenotype for the CVC that matches their corresponding physiological responses. Quantitative tomography provided data on the volume of the CVC and spongiome connections. Changes in the adhesion plaque during the pulsation cycle were also quantified and a dense filamentous network was observed. Together, the results suggest that the adhesion plaque mediates fluid discharge from the central vacuole, revealing new aspects of the osmoregulatory system in T. cruzi.

Asunto(s)

Presión Osmótica , Trypanosoma cruzi , Vacuolas , Trypanosoma cruzi/fisiología , Vacuolas/metabolismo , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/genética , Osmorregulación , Flagelos/metabolismo , Flagelos/fisiología , Enfermedad de Chagas/metabolismo , Mutación

RESUMEN

Cowpea is a leguminous plant belonging to the fabaceae family cultivated in the North and Northeast regions of Brazil, with productive potential. Among the abiotic factors, water deficiency is one of the main environmental limitations that influence agricultural production in the world. The objective of this work was to study the relative water content and osmoregulators of cowpea plants subjected to water stress. The experiment was carried out in a greenhouse at the Universidade Federal Rural da Amazônia (UFRA, Belém, PA), cowpea plants BR-17 Gurguéia Vigna unguiculata (L.) Walp were used. The experimental design was completely randomized (DIC) in a 2 × 2 factorial scheme, two water conditions (control and water deficit) and two times of stress (four and six days of water suspension), with 7 replications, totaling 28 experimental units. The water deficit affected plants, causing a reduction in relative water content (69.98%), starch (12.84% in leaves and 23.48% in roots) and carbohydrates (84.34%), and an increase in glycine-betaine, sucrose (114.11% in leaves and 18.71% in roots) and proline (358.86%) at time 2. The relative water content was negatively affected by water conditions, with a decrease in relation to the interaction of the aerial part and the root system. Therefore, greater metabolic responses were noted in plants that were subjected to stress treatment at time 2 (6 days).

Asunto(s)

Vigna , Agua , Deshidratación , Osmorregulación/fisiología , Betaína/análisis

RESUMEN

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.

Asunto(s)

Cadmio , Metabolismo Energético , Penaeidae , Contaminantes Químicos del Agua , Animales , Cadmio/toxicidad , Penaeidae/efectos de los fármacos , Penaeidae/fisiología , Penaeidae/crecimiento & desarrollo , Contaminantes Químicos del Agua/toxicidad , Metabolismo Energético/efectos de los fármacos , Osmorregulación/efectos de los fármacos

RESUMEN

Decapods occupy all aquatic, and terrestrial and semi-terrestrial environments. According to their osmoregulatory capacity, they can be osmoconformers or osmoregulators (hypo or hyperegulators). The goal of this study is to gather data available in the literature for aquatic decapods and verify if the rare hyporegulatory capacity of decapods is associated with hyper-regulatory capacity. The metric used to quantify osmoregulation was the osmotic capacity (OC), the gradient between external and internal (hemolymph) osmolalities. We employ phylogenetic comparative methods using 83 species of decapods to test the correlation between hyper OC and hypo OC, beyond the ancestral state for osmolality habitat, which was used to reconstruct the colonization route. Our analysis showed a phylogenetic signal for habitat osmolality, hyper OC and hypo OC, suggesting that hyper-hyporegulators decapods occupy similar habitats and show similar hyper and hyporegulatory capacities. Our findings reveal that all hyper-hyporegulators decapods (mainly shrimps and crabs) originated in estuarine waters. Hyper OC and hypo OC are correlated in decapods, suggesting correlated evolution. The analysis showed that species which inhabit environments with intense salinity variation such as estuaries, supratidal and mangrove habitats, all undergo selective pressure to acquire efficient hyper-hyporegulatory mechanisms, aided by low permeabilities. Therefore, hyporegulation can be observed in any colonization route that passes through environments with extreme variations in salinity, such as estuaries or brackish water.

Asunto(s)

Braquiuros , Decápodos , Animales , Osmorregulación , Filogenia , Decápodos/fisiología , Ecosistema

RESUMEN

The genetic basis underlying adaptive physiological mechanisms has been extensively explored in mammals after colonizing the seas. However, independent lineages of aquatic mammals exhibit complex patterns of secondary colonization in freshwater environments. This change in habitat represents new osmotic challenges, and additional changes in key systems, such as the osmoregulatory system, are expected. Here, we studied the selective regime on coding and regulatory regions of 20 genes related to the osmoregulation system in strict aquatic mammals from independent evolutionary lineages, cetaceans, and sirenians, with representatives in marine and freshwater aquatic environments. We identified positive selection signals in genes encoding the protein vasopressin (AVP) in mammalian lineages with secondary colonization in the fluvial environment and in aquaporins for lineages inhabiting the marine and fluvial environments. A greater number of sites with positive selection signals were found for the dolphin species compared to the Amazonian manatee. Only the AQP5 and AVP genes showed selection signals in more than one independent lineage of these mammals. Furthermore, the vasopressin gene tree indicates greater similarity in river dolphin sequences despite the independence of their lineages based on the species tree. Patterns of distribution and enrichment of Transcription Factors in the promoter regions of target genes were analyzed and appear to be phylogenetically conserved among sister species. We found accelerated evolution signs in genes ACE, AQP1, AQP5, AQP7, AVP, NPP4, and NPR1 for the fluvial mammals. Together, these results allow a greater understanding of the molecular bases of the evolution of genes responsible for osmotic control in aquatic mammals.

Asunto(s)

Delfines , Osmorregulación , Animales , Osmorregulación/genética , Cetáceos/genética , Mamíferos/genética , Agua Dulce , Vasopresinas/genética , Evolución Molecular , Filogenia

RESUMEN

Branchial chambers constitute the main osmoregulatory site in almost all decapod crustaceans. However, few studies have been devoted to elucidate the cellular function of specific cells in every osmoregulatory structure of the branchial chambers. In decapod crustaceans, it is well-known that the osmoregulatory function is localized in specific structures that progressively specialize from early developmental stages while specific molecular mechanisms occur. In this study, we found that although the structures developed progressively during the larval and postlarval stages, before reaching juvenile or adult morphology, the osmoregulatory capabilities of Litopenaeus vannamei were gradually established only during the development of branchiostegites and epipodites, but not gills. The cellular structures of the branchial chambers observed during the larval phase do not present the typical ultrastructure of ionocytes, neither Na+/K+-ATPase expression, likely indicating that pleura, branchiostegites, or bud gills do not participate in osmoregulation. During early postlarval stages, the lack of Na+/K+-ATPase immunoreactivity of the ionocytes from the branchiostegites and epipodites suggests that they are immature ionocytes (ionocytes type I). It could be inferred from IIF and TEM results that epipodites and branchiostegites are involved in iono-osmoregulation from PL15, while gills and pleura do not participate in this function.

Asunto(s)

Penaeidae , ATPasa Intercambiadora de Sodio-Potasio , Animales , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Osmorregulación , Equilibrio Hidroelectrolítico , Branquias , Larva/metabolismo , Salinidad

RESUMEN

Osmoregulatory abilities and mechanisms of adults and larvae of decapod crustaceans have been extensively investigated. However, how embryos carried by their mothers can deal with changing or extreme salinities is less understood. The egg membranes are believed to isolate embryos from a challenging environment, although osmoregulatory ability has been demonstrated in early developing embryos (naupliar stage) of two crabs. To establish whether embryos are isolated by their membranes and/or are able to osmoregulate, we measured the survival and volume change over 48 h of oocytes and embryos in different stages of three carideans (Betaeus lilianae, Palaemon macrodactylus and P. argentinus) and the brachyuran Neohelice granulata, subjected to different salinities. In addition, we recorded osmolality changes in homogenates of the same stages in P. argentinus and N. granulata after 2 h of exposure and mapped the presence of putative sites of ions exchange in the membrane of all species. High mortality, when it occurred, was associated with low salinity and mortality variation with the stage of development depended on the species. All species precipitated silver salts in or under the egg envelope, with a different pattern between carideans and the brachyuran. Changes in osmolality and egg volume after hypo- or hyper-osmotic salinity challenges indicate that eggs are not fully isolated by their membranes, and that some osmoregulatory mechanisms are in play to maintain developmental homeostasis. We suggest that egg membranes can participate in osmoregulation by selectively transporting ions to an intramembrane space, with differences between carideans and brachyurans.

Asunto(s)

Braquiuros , Decápodos , Animales , Braquiuros/fisiología , Osmorregulación , Salinidad , Equilibrio Hidroelectrolítico/fisiología

RESUMEN

Early marine invertebrates like the Branchiopoda began their sojourn into dilute media some 500 million years ago in the Middle Cambrian. Others like the Mollusca, Annelida, and many crustacean taxa have followed, accompanying major marine transgressions and regressions, shifting landmasses, orogenies, and glaciations. In adapting to these events and new habitats, such invertebrates acquired novel physiological abilities that attenuate the ion loss and water gain that constitute severe challenges to life in dilute media. Among these taxon-specific adaptations, selected from the subcellular to organismal levels of organization, and constituting a feasible evolutionary blueprint for invading freshwater, are reduced body permeability and surface (S) to volume (V) ratios, lowered osmotic concentrations, increased osmotic gradients, increased surface areas of interface epithelia, relocation of membrane proteins in ion-transporting cells, and augmented transport enzyme abundance, activity, and affinity. We examine these adaptations in taxa that have penetrated into freshwater, revealing diversified modifications, a consequence of distinct body plans, morpho-physiological resources, and occupation routes. Contingent on life history and reproductive strategy, numerous patterns of osmotic regulation have emerged, including intracellular isosmotic regulation in weak hyper-regulators and well-developed anisosmotic extracellular regulation in strong hyper-regulators, likely reflecting inertial adaptations to early life in an estuarine environment. In this review, we address osmoregulation in those freshwater invertebrate lineages that have successfully invaded this biotope. Our analyses show that across 66 freshwater invertebrate species from six phyla/classes that have transmuted into freshwater from the sea, hemolymph osmolalities decrease logarithmically with increasing S:V ratios. The arthropods have the highest osmolalities, from 300 to 650 mOsmoles/kg H2O in the Decapoda with 220-320 mOsmoles/kg H2O in the Insecta; osmolalities in the Annelida range from 150 to 200 mOsmoles/kg H2O, and the Mollusca showing the lowest osmolalities at 40-120 mOsmoles/kg H2O. Overall, osmolalities reach a cut-off at ∼200 mOsmoles/kg H2O, independently of increasing S:V ratio. The ability of species with small S:V ratios to maintain large osmotic gradients is mirrored in their putatively higher Na+/K+-ATPase activities that drive ion uptake processes. Selection pressures on these morpho-physiological characteristics have led to differential osmoregulatory abilities, rendering possible the conquest of freshwater while retaining some tolerance of the ancestral medium.

Asunto(s)

Agua Dulce , Osmorregulación , Animales , Evolución Biológica , Crustáceos/metabolismo , Moluscos/metabolismo , Osmorregulación/fisiología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Equilibrio Hidroelectrolítico/fisiología

RESUMEN

Salmonella Typhimurium is a pathogen of clinical relevance and a model of study in host-pathogen interactions. The virulence and stress-related periplasmic protein VisP is important during S. Typhimurium pathogenesis. It supports bacteria invading host cells, surviving inside macrophages, swimming, and succeeding in murine colitis model, O-antigen assembly, and responding to cationic antimicrobial peptides. This study aimed to investigate the role of the O-antigen molecular ruler WzzST and the periplasmic protein VisP in swarming motility and osmotic stress response. Lambda red mutagenesis was performed to generate single and double mutants, followed by swarming motility, qRT-PCR, Western blot, and growth curves. Here we demonstrate that the deletion of visP affects swarming under osmotic stress and changes the expression levels of genes responsible for chemotaxis, flagella assembly, and general stress response. The deletion of the gene encoding for the O-antigen co-polymerase wzzST increases swarming motility but not under osmotic stress. A second mutation in O-antigen co-polymerase wzzST in a ΔvisP background affected gene expression levels. The ΔvisP growth was affected by sodium and magnesium levels on N-minimum media. These data indicate that WzzST has a role in swarming the motility of S. Typhimurium, as the VisP is involved in chemotaxis and osmotic stress, specifically in response to MgCl2 and NaCl.

Asunto(s)

Antígenos O , Salmonella typhimurium , Animales , Proteínas Bacterianas/metabolismo , Quimiotaxis/genética , Flagelos/fisiología , Ratones , Antígenos O/genética , Antígenos O/metabolismo , Osmorregulación

RESUMEN

Soil salinity has been a limiting barrier for the production of vegetables in protected environments. Thus, the understanding of the sensitivity of species to this stress factor must be explored, seeking better growing conditions.Under the hypothesis that beet and radish crops are sensitive to variations in soil salinity, even at low levels, the objective of this work was to evaluate the development and productivity of these two species in soils with different salinities in a protected environment. The experimental design was completely randomized and treatments were formed by the soil salinity levels, obtained with the application of saline solution (NaCl in water), considering the soil electrical conductivity of 0.36 dS m-1as low salinity, of 1.05 dS m-1as moderate salinity and 2.43 dS m-1as elevated. For all variables analyzed, except for the relative chlorophyll index in beet plants, it was found that the increase in soil salinity resulted in significant development losses of beet and radish plants. Therefore, we concluded that beet and radish crops are sensitive to the variation in soil salinity, even in relatively low concentrations, making these species an unattractive choice for cultivation in systems that present this problem.(AU)

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A salinidade dos solos tem sido uma barreira limitadora para a produção de hortaliças em ambientes protegidos. Assim, o entendimento quanto a sensibilidade das espécies a esse fator de estresse deve ser explorado, buscando melhores condições de cultivo. Sob a hipótese de que as culturas de beterraba e rabanete são sensíveis às variações da salinidade do solo, mesmo em níveis baixos, o objetivo deste trabalho foi avaliar o desenvolvimento e a produtividade dessas duas espécies em solos comdiferentes salinidades em ambiente protegido. O delineamento experimental foi inteiramente casualizado e os tratamentos foram formados pelos níveis de salinidade do solo, obtidos com a aplicação de solução salina (NaCl em água), considerando a condutividade elétrica do solo de 0,36 dS m-1como baixa salinidade, de 1,05 dS m-1como salinidade moderada e 2,43 dS m-1como elevada. Para todas as variáveis analisadas, com exceção do índice relativo de clorofila em plantas de beterraba, verificou-se que o aumento da salinidade do solo resultou em perdas significativas de desenvolvimento de plantas de beterraba e rabanete. Assim, concluímos que as culturas de beterraba e rabanete são sensíveis à variação da salinidade do solo, mesmo em concentrações relativamente baixas, tornando essas espécies uma escolha pouco atrativa para cultivo em sistemas que apresentam este problema.(AU)

Asunto(s)

Suelos Salitrosos , Estrés Salino , Fotosíntesis/fisiología , Oxidación , Osmorregulación/fisiología

RESUMEN

PURPOSE: Annexins are proteins with important roles in parasites, some of which are related to excretion-secretion processes, protein traffic, and microvesicle functionality. The participation of annexins in osmoregulation has been reported in tapeworms, including Taenia solium. This study aimed to investigate the localization and expression of annexin in cysticerci of Taenia crassiceps, used as a model of cysticercosis. METHODS: We used an antibody made with a protein, previously employed on Schistosoma bovis, to detect annexin in T. crassiceps proteins extracts used Western blot assay. The histological distribution of annexin was studied with immunofluorescence and confocal microscopy. RESULTS: The antibody against annexin recognized a band at a molecular weight of 40.9 kDa. The histological distribution of annexin showed that the protein is mainly localized in the tegument and the protonephridia ducts. CONCLUSION: In our study, annexin was detected at a molecular weight similar to that described for Schistosoma bovis. In addition, its principal localization entailed structures of the osmoregulatory system one of the most important by the survival of the parasites. This confirms and solidifies previous reports concerning the role of annexins in T. crassiceps and this will be interesting by the development of new compounds against this protein.

Asunto(s)

Cisticercosis , Parásitos , Taenia solium , Animales , Anexinas/genética , Cysticercus , Ratones , Ratones Endogámicos BALB C , Osmorregulación

RESUMEN

Cattleya tigrina A. Rich has been suffering heavy losses in its natural habitat and it is now included in the list of plants that are vulnerable to extinction. The development of in vitro propagation and conservation methodologies, as well as acclimatization, are considered important for species at the risk of extinction, as they promote the multiplication and conservation of the species, hence avoiding the loss of their genetic variability. The present study established the protocol of micropropagation and the in vitro conservation of C. tigrina. For the in vitro propagation, the study tested two volumes of the MS medium and two medium consistencies (stationary liquid and semi-solid). For acclimatization, the substrate mixtures containing pine bark, charcoal, vermiculite, and coconut coir were analyzed. For the in vitro conservation, different concentrations of the salts were tested in the MS medium, together with the osmotic regulators (sucrose, mannitol, and sorbitol), and at two temperatures (18 and 25 °C). The results obtained inferred that the semi-solid medium was superior to the stationary liquid medium in the variables of survival and the presence of roots, while the liquid medium was superior to the semi-solid medium in the number of shoots. For acclimatization, pine bark was the substrate where the plants developed an improved height, with sprouting, and rooting. The conservation was satisfactory and the plants remained viable for a period of 730 days, with the MS medium with 25% of the salts, and at temperatures of 18 ºC or 25 ºC. The plants were propagated in the stationary liquid MS medium (10 mL) and the semi-solid medium (25 mL), while they were acclimatized in pine bark and preserved in the MS medium with 25% of the salts (18 ºC or 25 ºC).

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A Cattleya tigrina A. Rich vem sofrendo grandes perdas no seu habitat natural, sendo assim foi inclusa na lista de vulneráveis a extinção. O desenvolvimento de metodologias de propagação e conservação in vitro, bem como de aclimatização, são consideradas importantes para espécies em risco de extinção, por promover a multiplicação e conservação da espécie, evitando a perda do seu material genético. Desta forma, o presente trabalho visou estabelecer protocolo de micropropagação e conservação in vitro de C. tigrina. Para propagação in vitro testou volumes de meio de cultura e duas consistências do meio MS (líquido estacionário e semissólido). Para aclimatização, analisou misturas de substratos contendo casca de pinus, carvão vegetal, vermiculita e pó de coco. Para conservação in vitro, foram testados diferentes concentrações de sais no meio MS, reguladores osmóticos (sacarose, manitol e sorbitol), e duas temperaturas (18 e 25 °C). Os resultados obtidos inferem que, o meio de cultura semissólido foi superior ao líquido nas variáveis sobrevivência e presença de raízes, enquanto que o meio líquido foi superior ao meio semissólido em números de brotos. Na aclimatização a casca de pinus foi o substrato em que as plantas se desenvolveram melhor em altura, brotação e enraizamento. A conservação foi satisfatória e as plantas permaneceram viáveis por um período de 730 dias, usando 25% dos sais MS e temperatura de 18 ºC ou 25 ºC. As plantas podem ser propagadas em meio MS líquido estacionário (10 mL) ou semissólido (25 mL), aclimatizadas em casca de pinus e conservadas em 25% dos sais MS (18 ºC ou 25 ºC).

Asunto(s)

Especies en Peligro de Extinción , Orchidaceae/crecimiento & desarrollo , Orchidaceae/genética , Osmorregulación , Técnicas de Cultivo

RESUMEN

This study aimed to select and classify sunflower genotypes tolerant to lead (Pb) stress and evaluate their capacity of phytoextraction based on physiological, nutritional, and biochemical responses. Two experiments were carried out under lead stress. In the first experiment, out of 21 genotypes studied three showed higher relative biomass yield and were characterized as Pb-tolerant and five showed lower relative biomass production and were considered Pb-sensitive. In the second experiment, one Pb-tolerant (BRS-G27) and two Pb-sensitive (H251 and AG963) genotypes were studied. In this experiment, Pb stress reduced the growth and contents photosynthetic pigments in all genotypes, but more pronouncedly in sensitive genotypes. There were no substantial changes in micronutrient levels in the leaves and stem, but the levels of Cu and Mn in the stressed roots of sensitive genotypes were much lower than in BRS-G27. The contents of organic solutes in the roots suggest that sensitive genotypes have higher energy costs for osmoregulation by carbohydrates and amino acids synthesis. However, the accumulation of proline may be related to a greater Pb tolerance. Considering the results of dry mass yield, transfer coefficient, translocation factor, and tolerance index, the BRS-G27 genotype can be recommended for use in phytoremediation of Pb-contaminated soils.(AU)

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Este estudo teve como objetivo selecionar e classificar genótipos de girassol tolerantes ao estresse por chumbo (Pb) e avaliar sua capacidade de fitoextração com base nas respostas fisiológicas, nutricionais e bioquímicas. Dois experimentos foram realizados sob estresse de Pb. No primeiro experimento, dos 21 genótipos estudados, três apresentaram maior produção relativa de biomassa e foram caracterizados como tolerantes ao Pb e cinco apresentaram menor produção relativa de biomassa e foram considerados sensíveis ao Pb. No segundo experimento foram estudados um genótipo tolerante ao Pb (BRS-G27) e dois sensíveis ao Pb (H251 e AG963). Neste experimento, o estresse por Pb reduziu o crescimento e os teores de pigmentos fotossintéticos em todos os genótipos, porém, mais pronunciado em genótipos sensíveis. Não houve mudanças substanciais nos níveis de micronutrientes nas folhas e no caule, mas os níveis de Cu e Mn nas raízes estressadas de genótipos sensíveis foram muito mais baixos do que o BRS-G27. Os conteúdos de solutos orgânicos nas raízes sugerem que genótipos sensíveis apresentam maiores custos energéticos para osmorregulação por carboidratos e síntese de aminoácidos. No entanto, o acúmulo de prolina pode estar relacionado a uma maior tolerância ao Pb. Considerando os resultados de produção de massa seca, coeficiente de transferência, fator de translocação e índice de tolerância, o genótipo BRS-G27 pode ser recomendado para uso em fitorremediação de solos contaminados com Pb.(AU)

Asunto(s)

Micronutrientes , Osmorregulación , Genotipo , Helianthus , Indicadores y Reactivos , Plomo

RESUMEN

Primary adipsia is a rare condition in which there is failure in the activation threshold of the hypothalamic osmoreceptors, leading to osmolality imbalance. Here, we reported the case of a Pit Bull dog with an altered level of consciousness (started after weaning) and adipsia. There was an increase in plasma osmolality (444 mOsm/kg), sodium (223.7 mg/dL), and chlorine (173 mg/dL) levels. Based on the suspicion of primary adipsia, water was administered via a nasogastric tube, with clinical improvement. The owner was instructed to supply water with food. Eight months after discharge, the dog returned with parvovirus and died. In the anatomopathological examination, no structural changes were observed in the central nervous system. To our knowledge, this is the first report of hypernatremia due to adipsia in a Pit Bull dog, showing that this is a differential diagnosis that should be considered in this breed.

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Adipsia primária é uma rara condição em que há falha no limiar de ativação dos osmoreceptores hipotalâmicos, levando ao desequilíbrio da osmolalidade. Este artigo tem como objetivo relatar o caso de um cão da raça Pit Bull apresentando alteração no nível de consciência (iniciado após o desmame) e adipsia. Foi verificado aumento da osmolalidade plasmática (444 mOsm/kg), sódio (223,7 mg/dL) e cloro (173 mg/dL). Baseado na suspeita de adipsia primária, iniciou-se administração de água via sonda nasogástrica, com melhora clínica. O tutor foi orientado a fornecer água junto a alimentação. Oito meses após alta, o paciente retornou com parvovirose e veio a óbito. No exame anatomopatológico, não foram observadas alterações estruturais no sistema nervoso central. Este é o primeiro relato de hipernatremia por adipsia em um cão Pit Bull, mostrando que este é um diagnóstico diferencial que deve ser considerado nesta raça.

Asunto(s)

Animales , Masculino , Perros , Osmorregulación , Hipernatremia/veterinaria , Enfermedades Hipotalámicas/complicaciones , Enfermedades Hipotalámicas/veterinaria , Concentración Osmolar

RESUMEN

Dihydroxyacetone (DHA) can be used as an energy source by many cell types; however, it is toxic at high concentrations. The enzyme dihydroxyacetone kinase (DAK) has shown to be involved in DHA detoxification and osmoregulation. Among protozoa of the genus Trypanosoma, T. brucei, which causes sleeping sickness, is highly sensitive to DHA and does not have orthologous genes to DAK. Conversely, T. cruzi, the etiological agent of Chagas Disease, has two putative ATP-dependent DAK (TcDAKs) sequences in its genome. Here we show that T. cruzi epimastigote lysates present a DAK specific activity of 27.1 nmol/min/mg of protein and that this form of the parasite is able to grow in the presence of 2 mM DHA. TcDAK gene was cloned and the recombinant enzyme (recTcDAK) was expressed in Escherichia coli. An anti-recTcDAK serum reacted with a protein of the expected molecular mass of 61 kDa in epimastigotes. recTcDAK presented maximal activity using Mg+2, showing a Km of 6.5 µM for DHA and a K0.5 of 124.7 µM for ATP. As it was reported for other DAKs, recTcDAK activity was inhibited by FAD with an IC50 value of 0.33 mM. In conclusion, TcDAK is the first DAK described in trypanosomatids confirming another divergent metabolism between T. brucei and T. cruzi.

Asunto(s)

Fosfotransferasas (Aceptor de Grupo Alcohol)/aislamiento & purificación , Trypanosoma cruzi/enzimología , Secuencia de Aminoácidos , Animales , Western Blotting , Chlorocebus aethiops , Dihidroxiacetona/metabolismo , Dihidroxiacetona/toxicidad , Electroforesis en Gel de Poliacrilamida , Técnica del Anticuerpo Fluorescente , Masculino , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Osmorregulación , Fosfotransferasas (Aceptor de Grupo Alcohol)/química , Fosfotransferasas (Aceptor de Grupo Alcohol)/clasificación , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma cruzi/efectos de los fármacos , Células Vero

RESUMEN

Decapods have successfully colonized changing coastal habitats throughout the world by adapting their behavior, physiology, and biochemistry. Biochemical reserves, such as lipids and fatty acids (FAs), play fundamental roles in this adaptation process. These energy reserves are key for the development of decapods and their composition mainly depends on the type and quality of food available in their habitats. This study evaluated the lipid content and FA composition of three tissues (hepatopancreas, gills, and muscle) in two widely distributed, semi-terrestrial coastal crab species in Chile, Cyclograpsus cinereus from the upper intertidal and Hemigrapsus crenulatus from estuaries. This evaluation aimed to assess the physiological role of the bioenergetic reserves of these crabs, which tolerate fluctuating environmental conditions. Our results showed that both species had a higher lipid content in the hepatopancreas and a lower lipid content in its gills and muscle. All three of the evaluated tissues in C. cinereus showed high contents of saturated fatty acids (SFAs), and its hepatopancreas displayed the highest contents of monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs). In turn, H. crenulatus had the highest contents of MUFAs and PUFAs in its gills and muscle tissues, including an important amount of eicosapentaenoic acid (EPA). The FA content of C. cinereus may indicate an adaptive physiological response aimed at maintaining its cellular fluid balance during periods of desiccation in the upper intertidal zone. In contrast, the FAs found in H. crenulatus may be linked to the high activity of the sodium­potassium pump in its gills, in order to maintain osmoregulation in estuaries.

Asunto(s)

Adaptación Fisiológica , Braquiuros/fisiología , Ácidos Grasos/química , Lípidos/química , Aclimatación , Animales , Ecosistema , Ácido Eicosapentaenoico/metabolismo , Ácidos Grasos/metabolismo , Ácidos Grasos Insaturados/metabolismo , Branquias/metabolismo , Hepatopáncreas/metabolismo , Masculino , Modelos Biológicos , Músculos/metabolismo , Osmorregulación , Salinidad , Equilibrio Hidroelectrolítico

RESUMEN

Decapod crustaceans show variable degrees of euryhalinity and osmoregulatory capacity, by responding to salinity changes through anisosmotic extracellular regulation and/or cell volume regulation. Cell volume regulatory mechanisms involve exchange of inorganic ions between extra- and intra-cellular (tissue) compartments. Here, this interplay of inorganic ions between both compartments has been evaluated in four decapod species with distinct habitats and osmoregulatory strategies. The marine/estuarine species Litopenaeus vannamei (Lv) and Callinectes danae (Cd) were submitted to reduced salinity (15‰), after acclimation to 25 and 30‰, respectively. The freshwater Macrobrachium acanthurus (Ma) and Aegla schmitti (As) were submitted to increased salinity (25‰). The four species were salinity-challenged for both 5 and 10 days. Hemolymph osmolality, sodium, chloride, potassium, and magnesium were assayed. The same inorganic ions were quantified in muscle samples. Muscle hydration (MH) and ninhydrin-positive substances (NPS) were also determined. Lv showed slight hemolymph dilution, increased MH and no osmotically-relevant decreases in muscle osmolytes; Cd displayed hemolymph dilution, decreased muscular NaCl and stable MH; Ma showed hypo-regulation and steady MH, with no change in muscle ions; As conformed hemolymph sodium but hypo-regulated chloride, had stable MH and increased muscle NPS and ion levels. Hemolymph and muscle ions (especially chloride) of As were highly correlated (Pearson, +0.83). Significant exchanges between hemolymph and muscle ionic pools were more evident in the two species with comparatively less AER regulatory power, C. danae and A. schmitti. Our findings endorse that the interplay between extracellular and tissue ionic pools is especially detectable in euryhaline species with relatively lower osmoregulatory strength.

Asunto(s)

Decápodos/fisiología , Iones/metabolismo , Osmorregulación , Palaemonidae/metabolismo , Penaeidae/fisiología , Animales , Cadmio/metabolismo , Hemolinfa , Magnesio/química , Concentración Osmolar , Potasio/química , Salinidad , Cloruro de Sodio/química , Especificidad de la Especie , Equilibrio Hidroelectrolítico/fisiología