Biomedical subjects

M I Rodriguez-Garcia

Publications and source records attributed to M I Rodriguez-Garcia.

7 recordsLinked to original sources

PubMed2003

Distribution of pectins in the pollen apertures of Oenothera hookeri.velans ster/+ster.

Cell wall pectins are some of the most complex biopolymers known, and yet their functions remain largely mysterious. The aim of this paper was to deepen the study of the spatial pattern of pectin distribution in the aperture of Oenothera hookeri.velans ster/+ster fertile pollen. We used "in situ" immunocytochemical techniques at electron microscopy, involving monoclonal antibodies JIM5 and JIM7 directed against pectin epitopes in fertile pollen grains of Oenothera hookeri.velans ster/+ster. The same region was also analyzed by classical cytochemistry for polysaccharide detection. Immunogold labelling at the JIM7 epitope showed only in mature pollen labelling mainly located at the intine endo-aperture region. Cytoplasmic structures near the plasma membrane of the vegetative cell showed no labelling gold grains. In the same pollen stge the labelling at the JIM5 epitope was mostly confined to a layer located in the limit between the endexine and the ektexine at the level of the border of the oncus. Some tubuli at the base of the ektexine showed also an accumulation of gold particles. No JIM5 label was demonstrated in the aperture chamber and either in any cytoplasmic structure of the pollen grains. The immunocytochemical technique, when compared with the traditional methods for non-cellulose polysaccharide cytochemistry is fare more sensitive and allows the univocal determination of temporal and spatial location of pectins recognized by the JIM7 and JIM5 MAbs.

Antibodies, Monoclonal↗

PubMed2000

Annexin A11 (ANXA11) gene structure as the progenitor of paralogous annexins and source of orthologous cDNA isoforms.

The genomic organization of the annexin A11 gene was determined in mouse and human to assess its congruity with other family members and to examine the species variation in alternative splicing patterns. Mouse annexin A11 genomic clones were characterized by restriction analysis, Southern blotting, and DNA sequencing, and the homologous human gene (HGMW-approved gene symbol ANXA11) was deciphered from high-throughput genomic sequence with coanalysis of expressed sequence tags. Exons 6-15 of the tetrad core repeat region differ from annexins A7 and A13 but are spliced identically to other phylogenetic descendents, making annexin A11 the putative primary progenitor of up to nine paralogous human annexins. The 5' regions consist of untranslated exon 1, followed by an extensive intron 1 comprising almost half the total gene length of >40 kb, and additional GC-rich exons 2-5 encoding the proline- and glycine-rich amino-terminus. Distinct cDNA isoforms in cow and human were determined to be unique to each species and hence of dubious general significance for this gene's function. Multiple transcription start sites were revealed by primer extension analysis of the mouse gene, and transfection constructs containing the prospective promoter generated transcriptional activity comparable to that of the SV40 promoter. Internal repetitive elements and vicinal gene markers were mapped for the complete human annexin A11 gene sequence to characterize the surrounding genomic environment.

3T3 Cells↗

PubMed1999

Mouse annexin V genomic organization includes an endogenous retrovirus.

Mouse annexin V genomic clones were characterized by restriction analysis, Southern blotting and DNA sequencing. The entire gene spans close to 50 kb of the mouse genome and contains 14 exons ranging in size from 31 bp for exon 2 to 482 bp for exon 13 up to the polyadenylation site. Intron sizes range from 111 bp for intron 1b to more than 17 kb for intron 2. Non-coding exon 1 is present in two alternative forms separated by approx. 7.4 kb, and the two promoters associated with exons 1a and 1b are quite distinct. The upstream promoter has a TATA box and may direct the limited, tissue-specific expression of mRNA transcripts containing exon 1a. The downstream, TATA-less promoter has high G+C content, and exon 1b predominates among abundantly expressed mRNA species. The conservation of certain cis-elements, including Sp1, AP2, gamma-IRE and NF-IL6, in orthologous species of annexin V genes points to their possible role in trans-acting protein factor binding and gene regulation. Primer-extension analysis revealed multiple origins for transcription, with principal start sites 100-150 bp upstream of the ATG start codon in exon 2. Intron 4 was longer than that previously identified in the orthologous rat gene due to the integration of an apparently complete copy of the murine endogenous retrovirus element, MuERV-L. Phylogenetic analysis of annexin V from 12 species and the presence of neighbouring loci with paralogous counterparts linked to annexin VI pointed to the common ancestry of these genes via chromosomal duplication more than 600 million years ago.

Animals↗

PubMed1996

Mouse annexin V chromosomal localization, cDNA sequence conservation, and molecular evolution.

A full-length cDNA encoding mouse annexin V (ANX5) was cloned, sequenced, and utilized for chromosomal mapping. The gene lies on mouse chromosome 3 in close linkage with the fibroblast growth factor 2 (basic) gene and is syntenic with other genes known to have orthologous counterparts on human chromosome 4q. The open reading frame encoded a protein of 319 amino acids (aa), with 92-96% identity to ANX5 in other species. Internal repeat 3 of mouse ANX5 exhibited the highest level of nonconservative aa replacements with respect to other annexin subfamilies, but the greatest sequence conservation among ANX5 species members. This region may thus contain features that distinguish ANX5 from other annexins in properties or function. Phylogenetic analysis and homology testing of ANX5 members indicated that the 34-kDa annexin from Torpedo marmorata may also belong to this subfamily. Comparison of nine species of ANX5 led to an estimation of the unit evolutionary mutation rate at 1% aa replacements every 8 million years, comparable to other annexins.

Amino Acid Sequence↗

PubMed1996

Immunogold probes for light and electron microscopic localization of Ole e I in several Oleaceae pollens.

We investigated the immunolocalization of the olive major allergen Ole e I and Ole e I-like proteins in pollen from several Oleaceae species [olive (Olea europaea), ash (Fraxinus excelsior), privet (Ligustrum vulgaris), lilac (Syringa vulgare), and forsythia (Forsythia suspensa)]. Crossreactions among different pollens were found in enzyme immunoassays. For immunolocalization with light microscopy we used the silver enhancement technique with three monoclonal antibodies (1D8, 10H1, and 16G2) that recognize three different epitopes of the allergen Ole e I. Our findings show that the silver enhancement technique is very useful when several antibodies are to be used for rapid screening of different materials. MAb 10H1 gave the most precise results and was selected for further immunolocalization studies with transmission electron microscopy. The epitope recognized by this MAb was localized exclusively in the endoplasmic reticulum in olive pollen. In lilac, privet, and ash pollen, most of the reactivity was also seen in the endoplasmic reticulum; however, the 10H1 epitope was not detected in forsythia pollen.

Allergens↗

PubMed1996

rRNA distribution during microspore development in anthers of Beta vulgaris L. quantitative in situ hybridization analysis.

We related changes in the ultrastructural organization of the nucleoli with the results of quantitative in situ hybridizations to characterize rRNA metabolism during the development of microspore mother cells in the sugar beet anther (Beta vulgaris L.). In the course of meiotic prophase and early postmeiotic interphase the morphological characteristics of the nucleoli are typical of low or no transcriptional activity and a low rate of rRNA processing. However, we found evidence of an apparent increase in the relative numbers of 18 S rRNA transcripts in some stages of microsporogenesis. This was found in both the nucleoli and cytoplasm of pachytene meiocytes, and in later stages there was a spectacular accumulation of rRNA transcripts in nucleoli of the tetrad cells. Quantitative data are analyzed in the light of morphometric findings in the cell and their compartments to elucidate the degree to which changes in cell size are related to changes in labeling density and distribution. The results are discussed in terms of rRNA synthesis, transport and degradation as processes involved in the regulation of rRNA within microsporocytes and microspores.

Cell Nucleolus↗

PubMed1979

[Proof of the subapical differential growth of the flanks in the Chara rhizoid during graviresponse].

The displacement of resin spheres attached to the tip of the gravitropically bending Chara rhizoid was measured by means of time-lapse photography. The relative growth of the flanks which at the beginning of stimulation were opposite to each other, was calculated during the earliest response time. The physically upper subapical flank section continues growing after stimulation at a decreasing rate. The growth of the opposite lower flank section is inhibited immediately after stimulation by the position of the statoliths. As soon as the statoliths are displaced in a basal direction, the growth of this section is transiently promoted. The gravitropic downward bending of the Chara rhizoid is by bowing, not by bulging.

Chlorophyta↗