1,720,981 research outputs found
Microbes in rocks and meteorites: A new form of life unaffected by time, temperature, pressure
No full textCrystals, rocks and mineral ores of different origins contain viable microbial life that appears actively swimming under the microscope when the sample is properly fragmented and suspended in a nutrient medium. This form of life in rocks is unaffected by time, since microbes have been found in samples of all geological ages, from about 2.8 Ga to recent rocks, and by pressure and temperature, since it is present in metamorphic and in igneous rocks. From the tests performed, among which those to secure from sample pollution, it emerges that this form of life is not destroyed, as indeed expected, when the rock is heated above 500 °C in a kiln. However, all cloned microbes are sensitive to growth inhibition by specific antibiotics. A similar search, for the presence of microbes in meteorites, shows that also these materials are rich in microorganisms, indicating that these already existed in early Earth formation stages. Some different microbial species, derived from different samples of rocks and meteorites, have been cultured, cloned and classified by 16S rDNA typing and found to be not essentially different from present day organisms An interesting consequence of these findings, among others, is the support to the hypothesis that life came from outside Earth with the additional indication that it was already present in those materials that accreted to form the solar planetary system
Materiale organico ottenuto da rocce
No full textBrevetto per Invenzione N. RM2003A000026 del 23 gennai
DNA (cytosine-5) methyltransferase turnover and cellular localization in developing Paracentrotus lividus sea urchin embryo
No full textDNA (cytosine-5) methyltransferase turnover and cellular localization in developing Paracentrotus lividus sea urchin embryo
No full textLa caratterizzazione molecolare dell’ecosistema microbico psicrofilo per lo studio della stabilità delle sorgenti.
No full textCloning and molecular characterization of the first innexin of the phylum Annelida - Expression of the gene during development
No full textA novel member of the innexin family (cv-inx) has been isolated from the annelid polychaete worm Chaetopterus variopedatus using a PCR approach on genomic DNA and sequence analysis on genomic DNA clones. The gene is present in a HindIII-HindIII segment of 2250 bp containing an uninterrupted open reading frame of 1196 bp encoding a protein of 399 amino acids. The predicted protein shows the typical structural features of innexins and consensus sites for phosphorylation. Analyses on genomic DNA demonstrate that cv-inx is a single copy gene with no introns in the coding region, exactly corresponding to the cDNA sequence. The gene expression is regulated during development as shown by Northern blots analyses of the RNA and by immunoreaction with antibodies against the protein at several embryonic stages. The finding of an innexin in the phylum Annelida, outside of the Ecdysozoa clade, and its peculiar gene structure suggest the necessity to reconsider the current hypothesis on the origin and evolution of gap junctional proteins
DNA (cytosine-5) methyltransferase turnover and cellular localization in developing Paracentrotus lividus sea urchin embryo
No full textOrganization and nucleotide sequence of the cluster of five histone genes in the polichaete worm Chaetopterus variopedatus: First record of a H1 histone gene in the phylum Annelida
No full textHistone genes were identified and their nucleotide sequences were determined in the polychaete marine worm Chaetopterus variopedatus. The genes are organized in about 390 clusters of 7.3 kbp. Each cluster contains one copy of the five histone genes. The H1 histone gene present in the clusters is the first ever isolated in the phylum Annelida. The cluster has the unique peculiarity that all genes contain both the replication-dependent and the replication-independent 3' mRNA termination signals. Despite the differences in cluster organization and transcription polarity of the individual histone genes between C. variopedatus and Platynereis dumerilii, the other annelid in which histone genes have been studied, phylogenetic analysis of the encoded amino acid sequences clearly groups together those two organisms in a tree in which the other studied worms find closely related positions on the same evolutionary branch
In situ hybridization analysis of globin mRNAs in the primitive erythroid cells of the chick embryo
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