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Using the two cases of the Icelandic Health Sector Database and Russian initiatives in biobanking, the article criticizes the view of narratives and imaginaries as a sufficient and unproblematic means of shaping public understanding of genetics and justifying population-wide projects. Narrative representations of national biobanking engage particular imaginaries that are not bound by the universal normative framework of human rights, promote affective thinking, distract the public from recognizing and discussing tangible ethical and socioeconomic issues, and harm trust in science and technology. In the Icelandic case, the presentation of the project in association with national imaginaries concealed its market identity and could lead to the commodification of biodata. In the Russian case, framing in terms of "genetic sovereignty" and "civilizational code" offers pretexts for state securitization. Adherence to normative framework of human rights and public discussion of genetics in an argumentative and factual mode can counter these trends.
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Bancos de Muestras Biológicas , Humanos , Islandia , Federación de RusiaRESUMEN
Labyrinthulomycetes are mostly fungus-like heterotrophic protists that absorb nutrients in an osmotrophic or phagotrophic manner. Members of order Labyrinthulida produce unique membrane-bound ectoplasmic networks for movement and feeding. Among the various types of labyrinthulids' food substrates, diatoms play an important role due to their ubiquitous distribution and abundant biomass. We isolated and cultivated new diatom consuming Labyrinthulida strains from shallow coastal marine sediments. We described Labyrinthula diatomea n. sp. that differs from all known labyrinthulids in both molecular and morphological features. We provided strain delimitation within the genus Labyrinthula based on ITS sequences via haplotype network construction and compared it with previous phylogenetic surveys.
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Diatomeas/clasificación , Diatomeas/citología , Sedimentos Geológicos/parasitología , Análisis de Secuencia de ADN/métodos , ADN de Algas/genética , Diatomeas/aislamiento & purificación , Microscopía , Filogenia , Subunidades Ribosómicas Pequeñas de Eucariotas/genéticaRESUMEN
Two enigmatic groups of morphologically simple parasites of invertebrates, the Dicyemida (syn. Rhombozoa) and the Orthonectida, since the 19th century have been usually considered as two classes of the phylum Mesozoa. Early molecular evidence suggested their relationship within the Spiralia (=Lophotrochozoa), however, high rates of dicyemid and orthonectid sequence evolution led to contradicting phylogeny reconstructions. Genomic data for orthonectids revealed that they are highly simplified spiralians and possess a reduced set of genes involved in metazoan development and body patterning. Acquiring genomic data for dicyemids, however, remains a challenge due to complex genome rearrangements including chromatin diminution and generation of extrachromosomal circular DNAs, which are reported to occur during the development of somatic cells. We performed genomic sequencing of one species of Dicyema, and obtained transcriptomic data for two Dicyema spp. Homeodomain (homeobox) transcription factors, G-protein-coupled receptors, and many other protein families have undergone a massive reduction in dicyemids compared to other animals. There is also apparent reduction of the bilaterian gene complements encoding components of the neuromuscular systems. We constructed and analyzed a large dataset of predicted orthologous proteins from three species of Dicyema and a set of spiralian animals including the newly sequenced genome of the orthonectid Intoshia linei. Bayesian analyses recovered the orthonectid lineage within the Annelida. In contrast, dicyemids form a separate clade with weak affinity to the Rouphozoa (Platyhelminthes plus Gastrotricha) or (Entoprocta plus Cycliophora) suggesting that the historically proposed Mesozoa is a polyphyletic taxon. Thus, dramatic simplification of body plans in dicyemids and orthonectids, as well as their intricate life cycles that combine metagenesis and heterogony, evolved independently in these two lineages.
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Inverted repeats are common DNA elements, but they rarely overlap with protein-coding sequences due to the ensuing conflict with the structure and function of the encoded protein. We discovered numerous perfect inverted repeats of considerable length (up to 284 bp) embedded within the protein-coding genes in mitochondrial genomes of four Nematomorpha species. Strikingly, both arms of the inverted repeats encode conserved regions of the amino acid sequence. We confirmed enzymatic activity of the respiratory complex I encoded by inverted repeat-containing genes. The nucleotide composition of inverted repeats suggests strong selection at the amino acid level in these regions. We conclude that the inverted repeat-containing genes are transcribed and translated into functional proteins. The survey of available mitochondrial genomes reveals that several other organisms possess similar albeit shorter embedded repeats. Mitochondrial genomes of Nematomorpha demonstrate an extraordinary evolutionary compromise where protein function and stringent secondary structure elements within the coding regions are preserved simultaneously.
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Genes de Helminto/genética , Genes Mitocondriales/genética , Código Genético , Genoma Mitocondrial , Helmintos/genética , Secuencias Invertidas Repetidas/genética , Secuencia de Aminoácidos , Animales , Composición de Base , Secuencia de Bases , ADN de Helmintos/genética , ADN Ribosómico/genética , Complejo I de Transporte de Electrón/genética , Evolución Molecular , Femenino , Proteínas del Helminto/genética , Masculino , Consumo de Oxígeno , ARN de Helminto/genética , ARN Ribosómico 18S/genética , Selección Genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Especificidad de la EspecieRESUMEN
Molecular phylogenetic analysis of 18S rRNA gene sequences of nearly any species of Chytridiomycota has typically challenged traditional classification and triggered taxonomic revision. This has often led to the establishment of new taxa which, normally, appears well supported by zoospore ultrastructure, which provides diagnostic characters. To construct a meaningful and comprehensive classification of Chytridiomycota, the combination of molecular phylogenies and morphological studies of traditionally defined chytrid species is needed. In this work, we have studied morphological and ultrastructural features based on light and transmission electron microscopy as well as molecular phylogenetic analysis of a parasite (strain X-124 CCPP ZIN RAS) morphologically similar to Rhizophydium granulosporum living on the yellow-green alga Tribonema gayanum. Phylogenetic analysis of the 18S rRNA gene sequence of this strain supports that it represents a new genus and species affiliated to the recently established order Gromochytriales. The ultrastructure of X-124 confirms its phylogenetic position sister to Gromochytrium and serves as the basis for the description of the new genus and species Apiochytrium granulosporum. The 18S rRNA gene of A. granulosporum contains a S943 group I intron that carries a homing endonuclease pseudogene.
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Quitridiomicetos/clasificación , Quitridiomicetos/genética , Quitridiomicetos/ultraestructura , Microscopía , Microscopía Electrónica de Transmisión , Filogenia , ARN de Hongos/análisis , ARN Ribosómico 18S/análisisRESUMEN
The Monoblepharidomycetes is the sister class to the Chytridiomycetes in the phylum Chytridiomycota. The six known genera have thalli that are either monocentric and without rhizoids or produce hyphae with an independent evolutionary origin from the hyphae of higher fungi. On the basis of morphological characters and phylogenetic evidence from the small and large subunits of nuclear ribosomal RNA, we established two new genera, Sanchytrium and Telasphaerula, each with a single species. We re-analyzed intergeneric relationships within the monoblephs, and established two new families. The new genera significantly expand the known morphological and ecological diversity of the Monoblepharidomycetes by adding a monocentric, epibiotic, algal parasitic species and a rhizomycelial, saprotrophic species. Based on the presence of environmental sequences related to Sanchytrium strains, the Monoblepharidomycetes contain previously unsuspected diversity. The ribosomal DNA of the new genera contains an unusually high density of group I introns. We found 20 intron insertion positions including six that are new for rRNA genes (S1053, L803, L829, L961, L1844, and L2281).
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Quitridiomicetos/clasificación , Quitridiomicetos/genética , ADN Ribosómico/genética , Variación Genética , Intrones , Filogenia , Quitridiomicetos/citología , MicroscopíaRESUMEN
Copper (Cu2+) is an essential metal presented in the mammalian brain and released from synaptic vesicles following neuronal depolarization. However, the disturbance of Cu2+ homeostasis results in neurotoxicity. In our study we performed for the first time a combined functional investigation of cultured hippocampal neurons under Cu2+ exposure, its effect on spontaneous spike activity of hippocampal neuronal network cultured on multielectrode array (MEA), and development of long-term potentiation (LTP) in acute hippocampal slices in the presence of Cu2+. Application of 0.2mM CuCl2 for 24h reduced viability of cultured neurons to 40±6%, whereas 0.01mM CuCl2 did not influence significantly on the neuronal survival. However, exposure to the action of 0.01mM Cu2+ resulted in pronounced reduction of network spike activity and abolished LTP induced by high-frequency stimulation of Schaffer's collaterals in CA1 pyramidal neurons of hippocampal slices. Antioxidant Trolox, the hydrosoluble vitamin E analogue, prevented neurotoxic effect and alterations of network activity under Cu2+ exposure, but didn't change the impairment of LTP in Cu2+-exposured hippocampal slices. We hypothesized that spontaneous network neuronal activity probably is one of the potential targets of Cu2+-induced neurotoxicity, in which free radicals can be involved. At the same time, it may be suggested that Cu2+-induced alterations of long-lasting trace processes (like LTP) are not mediated by oxidative damage.
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Cobre/toxicidad , Neuronas/efectos de los fármacos , Animales , Supervivencia Celular/efectos de los fármacos , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Ratones , Transmisión Sináptica/efectos de los fármacosRESUMEN
BACKGROUND: Dental erosion is a common problem in modern societies, owing to the increased consumption of acid drinks such as soft drinks, sports drinks, fruit juice. Examining the enamel surface with the Atomic Force Microscopy (AFM) enables more precise registering and defining the changes of enamel surface structure and microhardness. This method can be used to compare the efficiency of application of different preventive and therapy materials and medicaments in dentistry. The chronic regular consumption of low pH cola drinks encouraged the erosion of the teeth. The loss of anatomy and sensitivity are direct results of acid cola dissolving coronal tooth material. Under the influence of coca cola, a change of crystal structure and nanomorphology on enamel surface occurs. AIM: This paper reflects dental damage from abusive cola drinking, and the clinical presentation can be explained from data presented in this thesis. MATERIAL AND METHODS: The trial was conducted on a total of 40 extracted teeth which were divided into two groups treated with the solution of coca cola during 5 minutes, and then prepared and tested with a standard AFM procedure, type SPM-5200. Quantitative analysis was performed by comparing the roughness parameters (Ra) of the treated and non-treated sample. RESULTS: Based on the test of a hypothesis of the existence of differences between the treated and untreated sample, with an application of a t-test, it is shown that there are statistically highly significant differences between Ra of the treated sample with a 5-minute treatment of coca cola and Ra of the same sample without the treatment. CONCLUSION: Use of AFM enables successful monitoring of changes on enamel surface as well as the interpretation of the ultrastructural configuration of the crystal stage and the damage created under the influence of different external factors.
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AIM: The paper presents research on the most common causes of exposure that leads to disorders of cholinesterase activity, as well as an overview of the results of cholinesterase activity with the poisoned people. MATERIAL AND METHODS: In a group of 35 acute poisoned patients by organophosphate compounds has led to inhibition of AchE. A total number of examined workers are 175 in the chemical industry and agricultural production in the area of Rasina District-Serbia. RESULTS: The results showed that among workers who are constantly exposed to pesticides, acetylcholinesterase is within the reference value. Having examined the medical records of these workers, it is noted that, at 72%, there is a slight fall of AchE activity, each year. The workers who had been exposed to pesticides at the time of testing had acetylcholinesterase regarding reference value, but 52% of them had a few years ago significantly reduced the value of the activity of acetylcholinesterase, which was treated and then transferred to other jobs. The 48% of these workers had acetylcholinesterase regarding benchmarks or were transferred to other jobs, for a variety of other health problems. CONCLUSION: Using each pesticide should only deal with people who are well versed in the way of its use, as well as the way of protecting them from poisoning.
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Many features of mitochondrial genomes of animals, such as patterns of gene arrangement, nucleotide content and substitution rate variation are extensively used in evolutionary and phylogenetic studies. Nearly 6,000 mitochondrial genomes of animals have already been sequenced, covering the majority of animal phyla. One of the groups that escaped mitogenome sequencing is phylum Kinorhyncha-an isolated taxon of microscopic worm-like ecdysozoans. The kinorhynchs are thought to be one of the early-branching lineages of Ecdysozoa, and their mitochondrial genomes may be important for resolving evolutionary relations between major animal taxa. Here we present the results of sequencing and analysis of mitochondrial genomes from two members of Kinorhyncha, Echinoderes svetlanae (Cyclorhagida) and Pycnophyes kielensis (Allomalorhagida). Their mitochondrial genomes are circular molecules approximately 15 Kbp in size. The kinorhynch mitochondrial gene sequences are highly divergent, which precludes accurate phylogenetic inference. The mitogenomes of both species encode a typical metazoan complement of 37 genes, which are all positioned on the major strand, but the gene order is distinct and unique among Ecdysozoa or animals as a whole. We predict four types of start codons for protein-coding genes in E. svetlanae and five in P. kielensis with a consensus DTD in single letter code. The mitochondrial genomes of E. svetlanae and P. kielensis encode duplicated methionine tRNA genes that display compensatory nucleotide substitutions. Two distant species of Kinorhyncha demonstrate similar patterns of gene arrangements in their mitogenomes. Both genomes have duplicated methionine tRNA genes; the duplication predates the divergence of two species. The kinorhynchs share a few features pertaining to gene order that align them with Priapulida. Gene order analysis reveals that gene arrangement specific of Priapulida may be ancestral for Scalidophora, Ecdysozoa, and even Protostomia.
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Genoma Mitocondrial , Animales , Secuencia de Bases , Teorema de Bayes , Codón , ADN Mitocondrial/química , ADN Mitocondrial/aislamiento & purificación , ADN Mitocondrial/metabolismo , Duplicación de Gen , Orden Génico , Reordenamiento Génico , Conformación de Ácido Nucleico , ARN de Transferencia de Metionina/química , ARN de Transferencia de Metionina/metabolismo , Análisis de Secuencia de ADNRESUMEN
This study assesses a protective effect of a mitochondria-targeted antioxidant SkQT1 (a mixture of 10-(6'-toluquinonyl) decyltriphenylphosphonium and 10-(5'-toluquinonyl) decyltriphenylphosphonium in proportion of 1.4:1), using an open focal trauma model of the rat brain sensorimotor cortex and a model of amyloid-beta1-42 (Abeta)-induced impairment of hippocampal long-term potentiation (LTP), a kind of synaptic plasticity associated with learning and memory. It was found that a trauma-induced neurological deficit could be partially improved with daily intraperitoneal injections of SkQT1 (250 nmol/kg) for 5 days after the trauma. Neither an analog of SkQT1 without thymoquinone (C12TPP) nor original thymoquinone without a cation residue was effective to improve such conditions. In the SkQ molecule, the phosphonium cation can be replaced by the rhodamine 19 cation, with the SkQTR1 being still active in the treatment of the neurological deficit. Application of 200 nM Abeta to rat hippocampal slices impaired the induction of LTP in the hippocampal CA1 pyramidal layer. A single intraperitoneal injection of SkQT1 (250 nmol/kg body weight) made 24 h before the slice preparation prevented the harmful effect of Abeta on the LTP. Thus mitochondria-targeted antioxidants, containing thymoquinone, have neuroprotective properties.
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Antioxidantes/farmacología , Benzoquinonas/farmacología , Región CA1 Hipocampal/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Compuestos Organofosforados/farmacología , Péptidos beta-Amiloides/toxicidad , Animales , Antioxidantes/administración & dosificación , Benzoquinonas/administración & dosificación , Benzoquinonas/química , Región CA1 Hipocampal/patología , Modelos Animales de Enfermedad , Inyecciones Intraperitoneales , Masculino , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Fármacos Neuroprotectores/administración & dosificación , Fármacos Neuroprotectores/farmacología , Compuestos Organofosforados/administración & dosificación , Fragmentos de Péptidos/toxicidad , Ratas , Ratas WistarRESUMEN
Bath application of 200 nM amyloid-ß1-42 (Aß) to rat hippocampal slices impairs induction of long-term potentiation (LTP) of the population spike in pyramidal layer of the CA1 field of the hippocampus. Intraperitoneal injection of mitochondria-targeted plastoquinone derivative SkQ1 at very low concentrations (250 nmol/kg body weight) given 24 h before the slice preparation or 1 h treatment of hippocampal slices with 250 nM SkQ1 prevents the deleterious effect of Aß on LTP. To elucidate which part of the molecule is responsible for this type of neuroprotective activity, the effect of the analog of SkQ1 lacking plastoquinone (C12TPP) was studied. It was found that C12TPP was much less efficient in LTP protection than SkQ1 itself. It means that the plastoquinone part of the SkQ1 molecule is responsible for the LTP rescue. To summarize, in vivo and in vitro injection of SkQ1 compensates for Aß-induced oxidative damage of long-term synaptic plasticity in the hippocampus, which is considered to be the main reason of memory loss and impairment of other cognitive functions associated with Alzheimer's disease. Therefore, SkQ1 may be considered as a promising candidate for the treatment of early-stage Alzheimer's disease.
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Péptidos beta-Amiloides/farmacología , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Fragmentos de Péptidos/farmacología , Plastoquinona/análogos & derivados , Análisis de Varianza , Animales , Biofisica , Estimulación Eléctrica , Técnicas In Vitro , Masculino , Técnicas de Placa-Clamp , Plastoquinona/farmacología , Ratas , Ratas WistarRESUMEN
Heat stress affects epigenetic gene silencing in Arabidopsis. To test for a mechanistic involvement of epigenetic regulation in heat-stress responses, we analyzed the heat tolerance of mutants defective in DNA methylation, histone modifications, chromatin-remodeling, or siRNA-based silencing pathways. Plants deficient in NRPD2, the common second-largest subunit of RNA polymerases IV and V, and in the Rpd3-type histone deacetylase HDA6 were hypersensitive to heat exposure. Microarray analysis demonstrated that NRPD2 and HDA6 have independent roles in transcriptional reprogramming in response to temperature stress. The misexpression of protein-coding genes in nrpd2 mutants recovering from heat correlated with defective epigenetic regulation of adjacent transposon remnants which involved the loss of control of heat-stress-induced read-through transcription. We provide evidence that the transcriptional response to temperature stress, at least partially, relies on the integrity of the RNA-dependent DNA methylation pathway.
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Arabidopsis/genética , Arabidopsis/fisiología , Metilación de ADN/genética , Calor , ARN de Planta/genética , Arabidopsis/enzimología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Elementos Transponibles de ADN/genética , ARN Polimerasas Dirigidas por ADN/genética , ARN Polimerasas Dirigidas por ADN/metabolismo , Epigénesis Genética , Histona Desacetilasas/genética , Histona Desacetilasas/metabolismo , Mutación , Proteínas de Plantas/genética , Regulación hacia ArribaRESUMEN
Soil salinity severely affects plant growth and agricultural productivity. AtbZIP24 encodes a bZIP transcription factor that is induced by salt stress in Arabidopsis thaliana but suppressed in the salt-tolerant relative Lobularia maritima. Transcriptional repression of AtbZIP24 using RNA interference improved salt tolerance in A. thaliana. Under non-stress growth conditions, transgenic A. thaliana lines with decreased AtbZIP24 expression activated the expression of stress-inducible genes involved in cytoplasmic ion homeostasis and osmotic adjustment: the Na(+) transporter AtHKT1, the Na(+)/H(+) antiporter AtSOS1, the aquaporin AtPIP2.1, and a glutamine synthetase. In addition, candidate target genes of AtbZIP24 with functions in plant growth and development were identified such as an argonaute (AGO1)-related protein and cyclophilin AtCYP19. The salt tolerance in transgenic plants correlated with reduced Na(+) accumulation in leaves. In vivo interaction of AtbZIP24 as a homodimer was shown using fluorescence energy transfer (FRET) with cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) as fused FRET pairs. Translational fusion of AtbZIP24 with GFP showed subcellular localization of the protein in nucleus and cytoplasm in plants grown under control conditions whereas in response to salt stress AtbZIP24 was preferentially targeted to the nucleus. It is concluded that AtbZIP24 is an important regulator of salt stress response in plants. The modification of transcriptional control by regulatory transcription factors provides a useful strategy for improving salt tolerance in plants.
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Proteínas de Arabidopsis/genética , Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Regulación de la Expresión Génica de las Plantas/genética , Redes Reguladoras de Genes , Adaptación Fisiológica , Arabidopsis/efectos de los fármacos , Arabidopsis/fisiología , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/química , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/fisiología , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Dimerización , Transferencia Resonante de Energía de Fluorescencia/métodos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Glucuronidasa/genética , Glucuronidasa/metabolismo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Presión Osmótica , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Interferencia de ARN , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Cloruro de Sodio/farmacologíaRESUMEN
We report an analysis of salt-stress responses in the monocotyledonous halophyte Festuca rubra ssp. litoralis. Salt-dependent expression of transcripts encoding a PIP2;1 aquaporin, V-ATPase subunit B, and the Na+/H+ antiporter NHX was characterized. Transcription of FrPIP2;1, FrVHA-B, and FrNHX1 was induced in root tissue of F. rubra ssp. litoralis by salt treatment, and during salt-stress F. rubra ssp. litoralis accumulated sodium in leaves and roots. Cell specificity of FrPIP2;1, FrVHA-B, and FrNHX1 transcription was analyzed by in situ PCR in roots of F. rubra ssp. litoralis. Expression of the genes was localized to the root epidermis, cortex cells, endodermis, and the vascular tissue. In plants treated with 500 mM NaCl, transcripts were repressed in the epidermis and the outer cortex cells, whereas endodermis and vasculature showed strong signals. These data demonstrate that transcriptional regulation of the aquaporin PIP2;1, V-ATPase, and the Na+/H+ antiporter NHX is correlated with salt tolerance in F. rubra ssp. litoralis and suggests coordinated control of ion homeostasis and water status at high salinity in plants. Salt-induced transcript accumulation in F. rubra ssp. litoralis was further monitored by cDNA-arrays with expressed sequence tags derived from a cDNA subtraction library. The salt-regulated transcripts included those involved in the control of gene expression and signal transduction elements such as a serine/threonine protein kinase, an SNF1-related protein kinase, and a WRKY-type transcription factor. Other ESTs with salt-dependent regulation included transcripts encoding proteins that function in metabolism, general stress responses, and defense and transport proteins.
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Aclimatación/efectos de los fármacos , Festuca/genética , Festuca/fisiología , Perfilación de la Expresión Génica , Redes Reguladoras de Genes , Tolerancia a la Sal/genética , Cloruro de Sodio/farmacología , Aclimatación/genética , Acuaporinas/metabolismo , Secuencia de Bases , Northern Blotting , Análisis por Conglomerados , Festuca/efectos de los fármacos , Festuca/crecimiento & desarrollo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Hidroponía , Iones , Modelos Biológicos , Análisis de Secuencia por Matrices de Oligonucleótidos , Especificidad de Órganos/efectos de los fármacos , Filogenia , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/enzimología , Hojas de la Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/citología , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Tolerancia a la Sal/efectos de los fármacos , Homología de Secuencia de AminoácidoRESUMEN
Salt stress is an environmental factor that severely impairs plant growth and productivity. Salinity-induced transcript accumulation was monitored in the salt-sensitive Arabidopsis thaliana and the related salt-tolerant Lobularia maritima using cDNA-arrays with expressed sequence tags derived from a cDNA subtraction library of salt-stressed L. maritima. The expression profiles revealed differences of the steady state transcript regulation in A. thaliana and L. maritima in response to salt stress. The differentially expressed transcripts include those involved in the control of gene expression as a transcription factor II homologue as well as signal transduction elements such as a serine/threonine protein kinase, a SNF1-related protein kinase AKIN10 homologue, and protein phosphatase 2C. Other ESTs with differential regulation patterns included transcripts encoding proteins with function in general stress responses and defense and included a peroxidase, dehydrins, enzymes of lipid and nitrogen metabolism, and functionally unclassified proteins. In a more detailed analysis the basic leucine zipper transcription factor AtbZIP24 showed differential transcript abundance in A. thaliana and L. maritima in response to salt stress. Transgenic AtbZIP24-RNAi lines showed improved growth and development under salt stress that was correlated with changed Cl(-) accumulation. The data indicate that AtbZIP24 functions as a transcriptional repressor in salt-stressed A. thaliana that negatively regulates growth and development under salinity in context of controlling Cl(-) homeostasis. Monitoring the differential and tissue specific global regulation of gene expression during adaptation to salinity in salt-sensitive and halotolerant plants is a promising and powerful approach to identify novel elements of plant salt stress adaptation.
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Adaptación Fisiológica/efectos de los fármacos , Arabidopsis/genética , Brassicaceae/genética , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Cloruro de Sodio/farmacología , Arabidopsis/efectos de los fármacos , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassicaceae/fisiología , Cloruros/metabolismo , Análisis por Conglomerados , Homeostasis/efectos de los fármacos , Análisis de Secuencia por Matrices de Oligonucleótidos , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/genética , Transporte de Proteínas/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Represoras/metabolismo , Plantones/efectos de los fármacos , Plantones/genética , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/metabolismoRESUMEN
BACKGROUND: Plants respond to extracellularly perceived abiotic stresses such as low temperature, drought, and salinity by activation of complex intracellular signaling cascades that regulate acclimatory biochemical and physiological changes. Protein kinases are major signal transduction factors that have a central role in mediating acclimation to environmental changes in eukaryotic organisms. In this study, we characterized the function of the sucrose nonfermenting 1-related protein kinase2 (SnRK2) SAPK4 in the salt stress response of rice. RESULTS: Translational fusion of SAPK4 with the green fluorescent protein (GFP) showed subcellular localization in cytoplasm and nucleus. To examine the role of SAPK4 in salt tolerance we generated transgenic rice plants with over-expression of rice SAPK4 under control of the CaMV-35S promoter. Induced expression of SAPK4 resulted in improved germination, growth and development under salt stress both in seedlings and mature plants. In response to salt stress, the SAPK4-overexpressing rice accumulated less Na+ and Cl- and showed improved photosynthesis. SAPK4-regulated genes with functions in ion homeostasis and oxidative stress response were identified: the vacuolar H+-ATPase, the Na+/H+ antiporter NHX1, the Cl- channel OsCLC1 and a catalase. CONCLUSION: Our results show that SAPK4 regulates ion homeostasis and growth and development under salinity and suggest function of SAPK4 as a regulatory factor in plant salt stress acclimation. Identification of signaling elements involved in stress adaptation in plants presents a powerful approach to identify transcriptional activators of adaptive mechanisms to environmental changes that have the potential to improve tolerance in crop plants.
Asunto(s)
Adaptación Fisiológica/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Proteína Quinasa 13 Activada por Mitógenos/metabolismo , Oryza/enzimología , Oryza/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Cloruro de Sodio/farmacología , Festuca/efectos de los fármacos , Festuca/enzimología , Festuca/genética , Genes de Plantas , Germinación/efectos de los fármacos , Oryza/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/enzimología , Hojas de la Planta/genética , Plantas Modificadas Genéticamente , Transporte de Proteínas/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Plantones/efectos de los fármacos , Plantones/enzimología , Plantones/genética , Plantones/crecimiento & desarrollo , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/enzimologíaRESUMEN
Lobularia maritima (Brassicaceae) is a facultative halophyte related to Arabidopsis thaliana and may be a suitable model to identify molecular mechanisms that regulate tolerance to salt stress in plants. Under the same salt stress conditions, the accumulation of sodium was similar in shoots and roots of Lobularia maritima and Arabidopsis thaliana, whereas the sodium to potassium ratio was less in Lobularia maritima. Aquaporins, the NHX-type Na(+)/H(+) antiporter, and the vacuolar ATPase are well established targets of regulation under salt stress that have a central role in the control of water status and cytoplasmic sodium homeostasis. Therefore, salt-dependent expression of transcripts encoding a PIP2;1 aquaporin, the Na(+)/H(+) antiporter NHX, and V-ATPase subunit E (VHA-E) was characterized in Lobularia maritima. Transcription of LmPIP2;1 was repressed in leaves and roots by treatment with 500mM NaCl. In contrast, salt stress stimulated the expression of LmNHX1 and LmVHA-E. Cell-specificity of the transcription of LmNHX1 was analyzed by fluorescence in situ PCR in leaf cross sections of Lobularia maritima. Expression of the gene was localized to the phloem and to mesophyll cells. In plants treated with 500 mM NaCl, transcription of LmNHX1 was stimulated in the mesophyll. The findings indicate divergent transcriptional responses of key mechanisms of salt adaptation in Lobularia maritima and suggest distinct regulation of sodium homeostasis and water flux under salt stress.