Biomedical subjects

X Carbonell

Publications and source records attributed to X Carbonell.

10 recordsLinked to original sources

PubMed1998

Insertional mutagenesis in the tailspike protein of bacteriophage P22.

The tailspike protein (TSP) of bacteriophage P22 is a homotrimeric multifunctional protein responsible for recognition and hydrolysis of Salmonella typhimurium host receptors. Once properly folded, TSP shows an unusual stability to temperature and detergent denaturation, prompting the analysis of TSP as a framework for the positioning of heterologous protein segments. We have explored the flexibility of inner sites and both amino and carboxy termini to accommodate foreign peptides for phage display. In the examined inner sites, TSP is extremely sensitive to minor sequence modifications, the folding intermediates being rapidly degraded. However, both the amino and carboxy termini are tolerant to peptide fusions, rendering stable and functional chimeric proteins. Surprisingly, the amino terminus, which connects the tail to the neck structure, can accept large peptide fusions, and the foreign amino acid stretches are solvent-exposed and highly antigenic on assembled, infectious virus particles.

Amino Acid Sequence↗

PubMed1996

Converging antigenic structure of a recombinant viral peptide displayed on different frameworks of carrier proteins.

A peptide reproducing the G-H loop amino acid sequence of foot-and-mouth disease virus VP1 protein was fused to the solvent-exposed C-terminus of the bacteriophage P22 tailspike protein [Carbonell and Villaverde (1996) Gene, in press], a homotrimeric polypeptide with a strong beta-helical structure. This fusion does not interfere with the biological activities of the phage tail. The antigenic profile of the complex antigenic site A within the G-H loop has been determined by competitive ELISA with a panel of monoclonal antibodies directed against different overlapping B-cell epitopes. The antigenic data have been compared with those obtained with a set of 12 chimeric beta-galactosidases displaying the G-H loop on different exposed regions. A high coincidence has been evidenced between the antigenicity of the viral peptide fused to the phage protein and that of some peptides inserted in an exposed loop of the activating interface of beta-galactosidase. This indicates that completely different structural frameworks of carrier proteins can provide similar constraints that allow the recombinant peptide to successfully mimic the antigenicity, and probably conformational features, of the natural peptide on the virion surface.

Antibodies, Monoclonal↗

PubMed1996

Peptide display on functional tailspike protein of bacteriophage P22.

The tailspike protein (TSP) of Salmonella typhimurium P22 bacteriophage is a multifunctional homotrimer, 6 copies of which are non-covalently attached to the capsid to form the virion tail in the last reaction of phage assembly. An antigenic peptide of foot-and-mouth disease virus (FMDV), aa 134-156 of protein VP1, has been joined to the carboxy terminus of TSP, and produced as a fusion protein in Escherichia coli directed by the trp promoter. The resulting fusion protein is soluble, stable, non-toxic, and can be easily purified by standard procedures. Moreover, both the endorhamnosidase and capsid assembly activities of the TSP are conserved, permitting the fusion protein to reconstitute infectious viruses by in vitro association with tailless particles. In both free TSP and P22 chimeric virions, the foreign peptide is solvent-exposed and highly antigenic, indicating that P22 TSP could be an appropriate carrier protein for multimeric peptide display.

Amino Acid Sequence↗

PubMed1995

A recombinant foot-and-mouth disease virus antigen inhibits DNA replication and triggers the SOS response in Escherichia coli.

The 3D gene of foot-and-mouth disease virus encodes the viral RNA dependent RNA polymerase, also called virus infection associated (VIA) antigen, which is the most important serological marker of virus infection. This 3D gene from a serotype C1 virus has been cloned and overexpressed in Escherichia coli under the control of the strong lambda lytic promoters. The resulting 51 kDa recombinant protein has been shown to be immunoreactive with sera from infected animals. After induction of gene expression, an immediate and dramatic arrest of cell DNA synthesis occurs, similar to that produced by genotoxic doses of the drug mitomycin C. This effect does not occur during the production of either a truncated VIA antigen or other related and non-related viral proteins. The inhibition of DNA replication results in a subsequent induction of the host SOS DNA-repair response and in an increase of the mutation frequency in the surviving cells.

Capsid↗

PubMed1995

Mitomycin C stimulates thermally induced recombinant gene expression in Escherichia coli MC strains.

The effects of mitomycin C on C1857-controlled recombinant gene expression have been explored in E. coli cultures when the drug was added simultaneously to the thermal induction. A significantly improved yield of homologous, heterologous and chimeric fusion proteins was observed in E. coli MC1061 and GE864 (a MC4100 derivative) thermoinduced cells. This feature was not detected in other E. coli strains and does not involve a gene dosage mechanism but a strain-dependent stimulation of gene expression unrelated to the RecA protease activity.

DNA, Bacterial↗

PubMed1993

Atrial natriuretic factor in neonatal hypoxic-ischemic encephalopathy.

The influence of perinatal asphyxia in the secretion of atrial natriuretic factor (ANF) during the first 6 days of life, and its renal consequences are discussed. Comparison between 20 healthy term neonates and 19 with first--or second--degree hypoxic-ischemic encephalopathy (HIE) is made. Daily controls were performed on clinical and neurological examinations and administration of sodium and fluids. On the first and sixth days of life, 24 hours urine collection, natremia, natriuresis, fractionated excretion of sodium and creatinine clearance were determined. The ANF was performed at 1, 2, 3 and 6 days old, by R.I.A. The full term newborns with HIE showed a peak in ANF values on day two, as does the control group, thereafter maintaining higher levels, with a significant difference on day three and six. No correlation could be found between the ANF levels and the renal variables analyzed.

Asphyxia Neonatorum↗

PubMed1989

[Sepsis and neonatal meningitis].

The epidemiological, clinical and bacteriological data of 38 infants under 28 days of age with a diagnosis of neonatal meningitis (13 patients), early neonatal sepsis (17 patients) or late neonatal sepsis (8 patients) were retrospectively reviewed. 52.6% of patients were premature and/or low weight neonates, 76.3% had an unfavorable obstetrical history and 39.4% had one or more underlying diseases. The clinical features were predominantly neurological (81.5%), cardiac or respiratory (71%) and gastrointestinal (34.2); the most outstanding laboratory data were positive CRP, hyperbilirubinemia and abnormalities in leukocyte differential count. The major microorganisms involved were E. coli (11 patients), S. agalactiae (9), S. aureus (5), L. monocytogenes (3) and coagulase-negative Staphylococcus (3). The overall incidence of these disorders was 3.33 cases/1000 live neonates, and the mortality rate was 7.9%.

Female↗

PubMed1987

[Systemic Candida infections].

Seven cases of neonatal systemic candidiasis are summarized. This means an incidence of 8.3% respect total amount of newborns admitted and 3.7% of babies admitted in the intensive care unit. Clinical presentation was not specific. Five blood cultures were positive and in two cases meningitis was recognized. Two cases died. Six cases were treated with amphotericin B and 5-fluorocytosine and in one case renal toxicity appear.

Amphotericin B↗

PubMed1983

De novo interstitial deletion of the long arm of chromosome 2 in a malformed newborn with a karyotype: 46,XY,del(2)(q12q14).

A male neonate with severe malformations, including facial dysmorphism, a short neck, postaxial-hexadactyly of the toes, congenital heart disease, hydronephrosis, imperforate anus and agenesis of corpus callosum, is described. His karyotype was 46,XYdel(2)(q12q14).

Abnormalities, Multiple↗

PubMed1977

Trisomy 20 mosaicism.

The first known case of trisomy 20 mosaicism is described. As in other cases of (partial) trisomy 20, the patient showed scarce physical malformations. It is suggested that trisomies for chromosomes of the F group are rare not because they are lethal but as a result of the morphology of the chromosomes involved.

Chromosomes, Human, 19-20↗