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Biomedical subjects

F Villalba

Publications and source records attributed to F Villalba.

7 recordsLinked to original sources
PubMed2001

Transposon impala, a novel tool for gene tagging in the rice blast fungus Magnaporthe grisea.

impala, a Tc1-mariner transposable element from Fusarium oxysporum, was introduced into the rice blast fungus Magnaporthe grisea to develop transposon-based insertional mutagenesis. A construct (pNIL160) containing an autonomous impala copy inserted in the promoter of niaD encoding Aspergillus nidulans nitrate reductase was introduced by transformation into a M. grisea nitrate reductase-deficient mutant. impala excision was monitored by restoration of prototrophy for nitrate. Southern analysis of niaD+ revertants revealed that impala was able to excise and reinsert at new loci in M. grisea. As observed for its host Fusarium oxysporum, impala inserted at a TA site left a typical excision footprint of 5 bp. We have shown that a defective impala copy was inactive in M. grisea, yet it can be activated by a functional impala transposase. A transformant carrying a single copy of pNIL160 was used to generate a collection of 350 revertants. Mutants either altered for their mycelial growth (Rev2) or nonpathogenic (Rev77) were obtained. Complementation of Rev77 with a 3-kb genomic fragment from a wild-type locus was successful, demonstrating the tagging of a pathogenicity gene by impala. This gene, called ORP1, is essential for penetration of host leaves by M. grisea and has no sequence homology to known genes.

Amino Acid Sequence↗
PubMed1999

Green fluorescent protein (GFP) as gene expression reporter and vital marker for studying development and microbe-plant interaction in the tobacco pathogen Phythphthora parasitica var. nicotianae.

PEG-mediated transformation of protoplasts in the presence of lipofectin was achieved in Phytophthora parasitica var. nicotianae, an oomycete pathogen of tobacco. Using oomycete promoter and terminator sequences, a plant-adapted green fluorescent protein (GFP) was introduced into the microorganism. The data show for the first time that this eukaryotic gene reporter can be used in an oomycete, both as a quantitative reporter of gene induction and as a vital marker allowing the study of development of Phytophthora in vitro and in the host plant.

Biomarkers↗
PubMed1995

WT1 exon 1 deletion/insertion mutations in Wilms tumor patients, associated with di- and trinucleotide repeats and deletion hotspot consensus sequences.

The WT1 gene is known to play a role in at least some cases of Wilms tumor (WT). The first exon of the gene is highly GC rich and contains many short tandem di- and trinucleotide repeats, interrupted direct repeats, and CCTG (CAGG) motifs that have been identified as hotspots for DNA deletions. We have analyzed 80 WT patient samples for mutations in the first exon of WT1, either by SSCP analysis of the first 131 bp of the coding portion of WT1 exon 1 or by size analysis of a PCR product encompassing the coding region of exon 1 in addition to flanking noncoding regions. We report here the occurrence of somatic and germ-line deletion and insertion mutations in this portion of the gene in four WT patients. The mutations are flanked by short direct repeats, and the breakpoints are within 5 nt of a CCTG (CAGG) sequence. These data suggest that a distinctive mutational mechanism, previously unrecognized for this gene, is important for the generation of DNA mutations at the WT1 locus.

Base Sequence↗
PubMedDate not supplied

[Iatrogenic bilateral hydrothorax following the placement of a central catheter].

We present a case of bilateral hydrothorax after internal jugular vein catheterization. 60 hours after placing the catheter, the patient showed an abrupt picture of jugular ingurgitation, abolished vesicular breath sounds, and displaced cardiac tones. It was necessary to immediately drain one hemithorax to guarantee ventilation of the patient. The present article examines iatrogenicity derived from the placement of central catheters, and special attention is given to the need for post-insertion x-ray control.

Adult↗
PubMedDate not supplied

[Influence of resting the digestive duct in gastric emptying. Comparison of 2 nutritional modalities: glucidic enteral and total parenteral nutrition].

Gastrointestinal motility is altered in several clinical situations in which Total Parenteral Nutrition (TPN) is indicated. Nevertheless, the effects of TPN on motility are not well known. In this study, Wistar rats (250-280 g) were divided into two groups were defined according to the route of administration of the nutrients: Group A (with TPN: 100% of the total non-protein calories administered as glucose), and Group B (solid enteral nutrition, but with the infusion of normal saline under the same conditions as in the previous group). Each group was subjected to three different infusion times: 24 hours, 3 days, and 5 days post-intervention, after which the gastric emptying was measured by means of the phenol red test. TPN delayed emptying in all the times with respect to group B, although significant differences were only found after 3 days of infusion.

Animals↗