Characterization and immunolocalization of RNA polymerase I transcription factor UBF with anti-NOR serum in protozoa, higher plant and vertebrate cells

We have used anti-NOR serum from a patient with rheumatoid arthritis, to study its reactivity on different phylogenetically separated species such as protozoa, higher plants, birds and mammals. The biochemical characteristics of the antigens detected after applying mono- and two-dimensional electrophoresis and electrophoretic transfers confirm that they correspond to the rRNA polymerase I transcription factor UBF. We have demonstrated the different molecular sizes, depending on the cell complexity, but the same neutral isoelectric points in whole cell extracts of the different species. We have also demonstrated an immunolocalization of this transcription factor to the fibrillar component in all the species studied. These results suggest a high conservation of UBF throughout evolution and the possibility of using this anti-NOR serum as a tool for the study of the structure, nucleolar organization and functional roles of the different nucleolar components

Development of Colletotrichum acutatum in the Foliar Tissue of Strawberry Plants

Strawberry anthracnose, caused by Colletotrichum acutatum, is one of the most destructive disease of this crop throughout the world. Assymptomatic stages in the plant have been the aim of this work. Inoculated leaves samples were taken at different times and they were processed for scanner electron microscopy (SEM) and transmission electron microscopy (TEM). Conidial development on both surfaces leaves was determined. The ultrastructural study of fungus penetration into plant cell was characterized by the formation of vesicles over the fungus periphery and is a morphological parameter of the intense membranes traffic, also could be a evidence of a transcriptional activity and enzymatic cell secretion. Differences of symptoms on both surfaces of leaves were observed

An experimental approach to the study of ag-nor proteins

Purified polyclonal antibodies have been obtained against 100 KD and 36 KD Ag-NOR proteins. These two antibodies have been used to study the immunolocalization of both proteins on different cell types subjected to various conditions of cell activity and to observe a nucleolar labelling with anti-36 kDa Ag-NOR protein antibody evenly distributed over the dense fibrillar component and granular component, and with anti-100 kDa mainly localized to the dense fibrillar component. After actinomycin D treatment, immunolabelling with both antibodies was found restricted to the granular zone of segregated nucleoli. Moreover, to further study the functional role of these proteins, we have used an electroporation system to introduce both antibodies into the nuclei of living cells, and have clearly detected a different nucleolar behaviour. The combination of these techniques has been shown to be an important tool to deepen the knowledge of the nucleolus and has allowed us to propose that the difference in nucleolar localization of the major 36 kDa and 100 kDa Ag-NOR proteins is the consequence of a different role of both proteins in the synthesis and processing of rRNA

<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Biological activity and redistribution of nucleolar proteins of two different cell lines treated with <i>cis</i>-dichloro-1,2-propylenediamine-<i>N,N,N',N'</i>-tetraacetato ruthenium (III) (RAP)</span>

579-588The interaction of a newly synthesized antitumor complex cis-dichloro-1,2-propylenediamine-N,N,N',N'-tetraacetato ruthenium (III) (RAP) with DNA was investigated in vitro through a number of techniques including comet assay, immunoprecipitation, and immunolocalization of certain nucleolar proteins (the upstream binding factor (UBF) and fibrillarin) involved in DNA transcription, rRNA processing, and ribosomal assembly. The results showed that RAP binds to the DNA of two cell lines (H4 and Hs-683) causing a delay in cell proliferation rate leading to a number of cellular modifications. These modifications include DNA-damage assessed by the single cell gel electrophoresis method (comet assay) and variation in the expression of nucleolar proteins; UBF was more abundant in RAP treated cells, this was explained by the high affinity of this protein to DNA modified by RAP. On the other hand, fibrillarin was found in less quantities in RAP treated cells which was explained by a de-regulation of the ribosomal machinery caused by RAP

Isolation, characterization and antitumour properties of the 1,2-propylenediaminetetraacetate-trans-diaqua-copper(II)

A trans-diaquacomplex formed by copper(II) sulphate and the sequestering polyamminopolycarboxylic ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been isolated and characterized by chemical analysis, titrimetry, FT-IR and electronic spectroscopy, Potentiometric and electronic measurements identified the ligand as tetradentate, two nitrogen and two oxygen atoms being bonded to the Cu(II) in planar positions. This octahedral monomeric soluble compound, is an unusual example of a copper (II) substance showing significant in vitro antitumour activity against the human ovarian tumour cells TG (ID50 = 2.29 μM at 48 h) and important in vivo antitumour activity against solid Sarcoma 180 with complete regression of the tumour at a dose of 12.5 mg/Kg body weight

Biological activity and redistribution of nucleolar proteins of two different cell lines treated with cis-dichloro-1,2-propylenediamine-N,N,N',N'-tetraacetato ruthenium (III) (RAP)

The interaction of a newly synthesized antitumor complex cis-dichloro-1,2-propylenediamine-N,N,N',N'-tetraacetato ruthenium (III) (RAP) with DNA was investigated in vitro through a number of techniques including comet assay, immunoprecipitation, and immunolocalization of certain nucleolar proteins (the upstream binding factor (UBF) and fibrillarin) involved in DNA transcription, rRNA processing, and ribosomal assembly. The results showed that RAP binds to the DNA of two cell lines (H4 and Hs-683) causing a delay in cell proliferation rate leading to a number of cellular modifications. These modifications include DNA-damage assessed by the single cell gel electrophoresis method (comet assay) and variation in the expression of nucleolar proteins; UBF was more abundant in RAP treated cells, this was explained by the high affinity of this protein to DNA modified by RAP. On the other hand, fibrillarin was found in less quantities in RAP treated cells which was explained by a de-regulation of the ribosomal machinery caused by RA

Ultrastructure of the early stages of Colletotrichum acutatum infection of strawberry tissues

The early stages of the infection of attached leaves and petioles of strawberry (Fragaria ×ananassa Duch. ‘Camarosa’) by Colletotrichum acutatum Simmonds were studied using scanning and transmission electron microscopy. Pre-penetration events of these tissues were similar, but the production of secondary conidia (microcyclic conidiation) was detected only on leaves. At the ultrastructural level, different stages of maturation of appressoria were observed and described. In young appressoria, the cell wall was composed of two layers and the plasma membrane displayed a wavy appearance. In the following stage, the appressorium developed a third electron-transparent layer between the cell wall and the plasma membrane. This new electron-transparent material was especially visible in the region of the appressorium near the cuticle. The plasma membrane of this appressorium showed a smooth appearance. Afterwards, a penetration peg emerged through the pore penetrating the cuticle and reached the epidermal wall where it enlarged to form an intramural infection vesicle. Both structures of infection, the penetration peg and the intramural infection vesicle, produced during the early phases of infection of strawbery tissues by C. acutatum, have not been previously reported and confirm that its invasion strategy is that of a subcuticular intramural pathogen. Once the infection was well established, abundant subcuticular and intramural hyphae were produced on petioles, causing severe degradation of the host cell walls. Occasionally, the cuticle appeared disrupted in those regions where the host walls were very degraded and dilated. Differences between colonization of petioles and leaves were observed.À l’aide de la microscopie électronique par balayage et par transmission, les auteurs ont étudié les premiers stades de l’infection des feuilles attachées et des pétioles du fraisier (Fragaria ×ananassa Duch. ‘Camarosa’), par le Colletotrichum acutatum Simmonds. Les évènements de pré-pénétration de ces tissus sont similaires, mais la production de conidies secondaires (conidiation microcyclique) ne s’observe que sur les feuilles. Les auteurs ont observé et décrivent les ultrastructures, aux différents stades de maturation des appressoriums. Chez les jeunes appressoriums, la paroi cellulaire est composée de deux couches et la membrane plasmique montre une apparence ondulée. Au stade suivant, l’appressorium développe une troisième couche transparente aux électrons, entre la paroi cellulaire et la plasmalemme. Ce nouveau matériel transparent aux électrons est particulièrement visible dans la région de l’appressorium voisin de la cuticule. La plasmalemme de cet appressorium est d’apparence lisse. Par après, l’hyphe de pénétration émerge à travers le pore et pénètre la cuticule pour atteindre la paroi épidermique, où il s’élargit pour former une vésicule d’infection intramurale. Les deux structures d’infection, hyphe de pénétration et vésicule d’infection intramurale, produites au cours des premières phases d’infection des tissus du fraisier par le C. acutatum, n’ont jamais été rapportées jusqu’ici et confirment sa stratégie d’invasion par pathogénèse subcuticulaire intra murale. Une fois l’infection bien établie, on observe la formation de nombreux hyphes subcuticulaires et intramuraux sur les pétioles, entraînant la dégradation des parois des cellules de l’hôte. Occasionnellement, la cuticule apparaît éclatée dans les régions où les parois de l’hôte sont vraiment dégradées et dilatées. On observe des différences entre la colonisation des pétioles et des feuilles