Biomedical subjects

Pablo Castillo

Publications and source records attributed to Pablo Castillo.

3 recordsLinked to original sources

PubMed2006

Application of the secondary structure model of rRNA for phylogeny: D2-D3 expansion segments of the LSU gene of plant-parasitic nematodes from the family Hoplolaimidae Filipjev, 1934.

Knowledge of rRNA structure is increasingly important to assist phylogenetic analysis through reconstructing optimal alignment, utilizing molecule features as an additional source of data and refining appropriate models of evolution of the molecule. We describe a procedure of optimization for alignment and a new coding method for nucleotide sequence data using secondary structure models of the D2 and D3 expansion fragments of the LSU-rRNA gene reconstructed for fifteen nematode species of the agriculturally important and diverse family Hoplolaimidae, order Tylenchida. Using secondary structure information we converted the original sequence data into twenty-eight symbol codes and submitted the transformed data to maximum parsimony analysis. We also applied the original sequence data set for Bayesian inference. This used the doublet model with sixteen states of nucleotide doublets for the stem region and the standard model of DNA substitution with four nucleotide states for loops and bulges. By this approach, we demonstrate that using structural information for phylogenetic analyses led to trees with lower resolved relationships between clades and likely eliminated some artefactual support for misinterpreted relationships, such as paraphyly of Helicotylenchus or Rotylenchus. This study as well as future phylogenetic analyses is herein supported by the development of an on-line database, NEMrRNA, for rRNA molecules in a structural format for nematodes. We also have developed a new computer program, RNAstat, for calculation of nucleotide statistics designed and proposed for phylogenetic studies.

Animals↗

PubMed2006

Steroid-responsive encephalopathy associated with autoimmune thyroiditis.

BACKGROUND: Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), often termed Hashimoto encephalopathy, is a poorly understood and often misdiagnosed entity. OBJECTIVE: To characterize the clinical, laboratory, and radiologic findings in patients with SREAT to potentially improve recognition of this treatable entity. DESIGN: Retrospective analysis of clinical features and diagnostic test data. SETTING: Two affiliated tertiary care referral institutions. PATIENTS: Twenty consecutive (6 male) patients diagnosed as having SREAT from 1995 to 2003. MAIN OUTCOME MEASURES: Clinical features and ancillary test findings associated with SREAT. RESULTS: The median age at disease onset was 56 years (range, 27-84 years). The most frequent clinical features were tremor in 16 (80%), transient aphasia in 16 (80%), myoclonus in 13 (65%), gait ataxia in 13 (65%), seizures in 12 (60%), and sleep abnormalities in 11 (55%). All patients were assigned an alternative misdiagnosis at presentation, most commonly viral encephalitis (n = 5), Creutzfeldt-Jakob disease (n = 3), or a degenerative dementia (n = 4). The most frequent laboratory abnormalities were increased liver enzyme levels in 11, increased serum sensitive thyroid-stimulating hormone levels in 11, and increased erythrocyte sedimentation rate in 5. In only 5 patients (25%) did cerebrospinal fluid abnormalities suggest an inflammatory process. Magnetic resonance imaging abnormalities believed to be related to the encephalopathy were present in 5 patients (26%). CONCLUSIONS: The clinical, laboratory, and radiologic findings associated with SREAT are more varied than previously reported. Misdiagnosis at presentation is common. This treatable syndrome should be considered even if the serum sensitive thyroid-stimulating hormone level and erythrocyte sedimentation rate are normal, the cerebrospinal fluid profile does not suggest an inflammatory process, and neuroimaging results are normal. Until the pathophysiologic mechanism of this and other autoimmune encephalopathies is better characterized, we believe that descriptive terms that reflect an association rather than causation are most appropriate for this syndrome.

Adult↗

PubMed2004

Isolation and characterization of PRA1, a trypsin-like protease from the biocontrol agent Trichoderma harzianum CECT 2413 displaying nematicidal activity.

Mycoparasitic Trichoderma strains secrete a complex set of hydrolytic enzymes under conditions related to antagonism. Several proteins with proteolytic activity were detected in culture filtrates from T. harzianum CECT 2413 grown in fungal cell walls or chitin and the protein responsible for the main activity (PRA1) was purified to homogeneity. The enzyme was monomeric, its estimated molecular mass was 28 kDa (SDS-PAGE), and its isoelectric point 4.7-4.9. The substrate specificity and inhibition profile of the enzyme correspond to a serine-protease with trypsin activity. Synthetic oligonucleotide primers based on N-terminal and internal sequences of the protein were designed to clone a full cDNA corresponding to PRA1. The protein sequence showed <43% identity to mammal trypsins and 47-57% to other fungal trypsin-like proteins described thus far. Northern analysis indicated that PRA1 is induced by conditions simulating antagonism, is subject to nitrogen and carbon derepression, and is affected by pH in the culture media. The number of hatched eggs of the root-knot nematode Meloidogyne incognita was significantly reduced after incubation with pure PRA1 preparations. This nematicidal effect was improved using fungal culture filtrates, suggesting that PRA1 has additive or synergistic effects with other proteins produced during the antagonistic activity of T. harzianum CECT 2413. A role for PRA1 in the protection of plants against pests and pathogens provided by T. harzianum CECT 2413 is proposed.

Amino Acid Sequence↗