1,721,109 research outputs found
Characterisation of Vigna unguiculata (L.) Walp cultivars and ecotypes from Mozambique by molecular markers
No full textChloropastic ycf2 Gene Expression in Stressed Plants
No full textThe chloroplast ycf2 gene plays a vital unknown function in the higher plants: gene silencing or reduction in mRNA synthesis induce cell death (Drescher et al., 2000).
Using the SSH technique, Bernardi et al. (2008) isolated a cDNA sequence in cold tolerant plants of Olea europaea L. showing a very high expression of the ycf2 gene induced by cold treatment.
The olive gene was isolated and sequenced. It presents a 6385 nucleotide length and the sequence is highly conserved in the plants, also in the rudimentary plastid genome of the non-photosynthetic parasitic Epifagus virginiana (Wolfe et al., 1992), thus confirming an essential role for the plant survival. The hypothetical protein sequence is constituted of 2278 amino acids presenting an ATPase domain and a DUF825 domain with unknown function.
We have focused our work on the fruit development of O. europaea in order to verify if ycf2 may have a specialized function in non-photosynthetic tissues during seed maturation, as reported for tomato by Richards et al. (1994). Semi-quantitative RT-PCR using mRNA extracted at different maturation stages indicated that mRNA is present in fruits of all stages, although the higher concentration was found in leaves.
Analysis of ycf2 transcripts in poplar plants treated with ozone and in plane infected with Ceratocystis fimbriata, agent of the colored canker, confirmed a differential expression of the gene after the stressing treatments.
All the results point to a defense activation of ycf2 both in biotic and abiotic stresses
Phaseolus coccineus storage proteins. Extraction and characterization.
No full textPhaseolus coccineus storage globulins were extracted from mature cotyledons, purified and characterized. Three major proteins were separated. A component showing erythroagglutinating activity was thoroughly purified by thyroglobulin-Sepharose chromatography. The relative molecular masses of the three fractions are Mr = 330, 178, and 500 kDa as determined by polyacrylamide gel electrophoresis (PAGE). They correspond to the proteins found in other systems and classified as phytohaemagglutinin (PHA), vicilin and legumin, respectively. Electrophoretic analyses under denaturating conditions (SDS-PAGE) evidenced the major subunits for the three proteins. Isoelectrofocusing of the isolated proteins indicated a large heterogeneity for vicili
Modificazioni del pattern delle proteine solubili in foglie di Zea mays L. cresciute in presenza di SO2
No full textTranscriptome analyses of O3 –responsive genes in leaves of two differentially susceptible poplar genotypes
No full textWhen subjected to episodic ozone peaks, the more sensitive trees can undergo conspicuous molecular and physiological changes that frequently result in foliar lesion formation. These events involve programmed cell death and other events typical of hypersensitive responses triggered by pathogens or abiotic stressors. By using the microarray technology, a transcriptome investigation was carried out on the leaves from two poplar clones exhibiting a contrasting susceptibility in terms of leaf injuries after an acute ozone exposure, with the aim to understand the molecular events at the base of foliar lesion formation. Unfumigated plants were used as controls. The microarray platform consisted in a collection of cDNAs extracted from different organisms subjected to abiotic (ozone and cold stress) or biotic (ceratoplatanin phytotoxic protein) stresses. The genes modulated by ozone were compared with those of the untreated sensitive and tolerant clones. Out of the 337 genes, 119 and 41 genes were evidenced to be specifically O3-responsive in Eridano and in I-214 poplar clones respectively. In both the genotypes (but especially in the Eridano clone), the down-regulated genes were higher in number than the up-regulated ones. Interestingly, sensitive and resistant genotypes evidenced some genes specifically up or down expressed only in one of the two clones. These genes could play a key role in determining the different behaviour displayed by the two clones when exposed to acute ozone stress and constitute an intriguing opportunity to better understand the molecular bases of ozone stress tolerance and sensitivity. The differentially expressed genes were also compared in sensitive clones with respect to tolerant counterpart at different experimental time points (before ozone exposure, at fumigation end, and during the recovery times). The obtained results evidenced that about the 22 of all transcripts were differentially regulated overtime in the two clones: the majority of these belonged to cell metabolism (primary and secondary) and disease/defence functional categories and resulted mainly down-regulated in the sensitive clone than in the tolerant one. At 5 hrs treatments and during the subsequent recovery periods, the categories having the major number of differentially transcribed genes were those related to cell metabolism and signal transduction pathways. A significant increase in expressed genes from disease/defence and protein synthesis categories was evidenced after ozone stress. Considering the differences displayed by the two clones in the expressed transcriptome, we suggest that a more or less efficient deployment of defence mechanisms minimizing the toxic effect of O3 or its by-products can explain the differences in ozone sensitivity showed by the two poplar hybrids. The transcription profiles, obtained by using these cDNA microarray platforms, indicated that several genes differentially regulated by ozone in Eridano and I-214 poplar clones were the same regulated by other abiotic or biotic stressors in different organisms, underlying the existence of a conserved and interspecific network of genes, activated during plant defence responses
Photosynthesis and water potential components in maize seedlings under wet and drought conditions
No full textGene expression analyses reveal a relationship between conidiation and cerato-platanin in homokaryotic and heterokaryotic strains of the fungal plant pathogen Heterobasidion irregulare
Full text linkThe Basidiomycete Heterobasidion irregulare was recently sequenced and three cerato-platanin encoding genes were found in its genome (HiCPs). Cerato-platanin family proteins (CPPs) are produced by both plant pathogenic and non-pathogenic fungi, and can act both as virulence factors and elicitors of defence responses. In fungal life these proteins seem to play a dual role, in the fungal cell wall and in the fungus-plant interaction, but most data available to date on CPPs derive from studies performed on Ascomycetes. In the present study, we investigated the expression of HiCPs in three homokaryotic isolates and two heterokaryotic isolates of the forest pathogen H. irregulare. Transcription of HiCPs was analysed both at the edge and at the centre of the fungal colony and compared between homokaryon and heterokaryon. Results showed that only HiCP1 and HiCP2 are likely to be translated in H. irregulare and that, under the tested conditions, HiCP1 is by far the gene with the highest transcript abundance among HiCPs. HiCP1 did not show any preferential expression in different sections of the fungal colony, while HiCP2 was significantly more expressed at the colony centre, thus suggesting a link with the production of conidia. The level of expression of HiCPs in heterokaryons was generally comparable to that of one or both the parental homokaryons, irrespective of the colony section, thus demonstrating that HiCPs are not transcriptionally influenced by the heterokaryotic stage
PCR based genome subtractive hybridization on Curtobacterium flaccumfaciens pv. flaccumfaciens for the detection of pathogenicity and virulence determinants
No full textModulation of gene expression in the rat brain by acetyl-l-carnitine
No full textAcetyl-l-carnitine (ALC) has been shown to exhibit many neuromodulatory and neurotrophic actions on neuron activity. It is a molecule of considerable interest for its clinical application in various disorders, including Alzheimer’s disease and painful neuropathies. Studies reported that ALC treatment produces long lasting effects in learning processes, suggesting an involvement of gene modulation. The ALC action on gene expression is recently revealed by suppression subtractive hybridization method studies for the generation of subtracted cDNA libraries and the subsequent identification of differentially expressed transcripts after ALC treatment of rats (Traina et al., Mol. Brain Res, 132, 57-63, 2004). The technique generates an equalized representation of differentially expressed genes and it is based on the construction of forward and reverse cDNA libraries that allow the identification of the genes that are regulated after ALC treatment. We have singled out a multifocal control of ALC: i) an up-regulation of both 14, 3, 3 protein, gamma subunit, and of heat shock protein 72, contributing to establish a cytoprotective state in inflammation, neurodegenerative disorders, and aging; ii) a down-regulation of ATP-synthase lipid-binding protein, and positively increases lysosomal H+ATPase gene expression. The effects have implications in ceroid lipofuscinosis pathology. In addition, ALC treatment up-regulates VDAC1 gene expression that might exert an antiapoptotic role, and seems to have a pivotal role on synaptic plasticity (Traina et al., Neurochem. Int., in press). Finally, ALC down-regulates ferritin-H expression, and myelin basic protein, and up-regulates kinesin1 light chain, responsible for many of the microtubule-dependent transport pathways for fast anterograde axonal transport. It is associated with amyloid precursor proteins. Our data on gene expression, therefore, might be of relevant importance for a human treatment of many clinical malignancies
Ribosamal RNA characterization in the leech Hirudo medicinalis
No full textIn the present study the ribosomal RNA of the leech Hirudo medicinalis has been characterized at the aim of identifying possible analogies with other invertebrates. Upon electrophoresis on denaturating gels, ribosomal RNA fraction of H. medicinalis exhibited a remarkable thermal instability by dissociating into two hydrogen-bonded components when heated at 60° C, at variance with the behaviour of the rat rRNA, which does not show this process. This result suggests a functional role in leech ribosome organisation that requires deeper structural studies
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