Biomedical subjects

I Pala

Publications and source records attributed to I Pala.

3 recordsLinked to original sources

PubMed2005

Contrasting views over a hybrid complex: Between speciation and evolutionary "dead-end".

The Squalius alburnoides complex, of hybrid origin, comprises diploid, triploid and tetraploid forms and has a widespread distribution in the Iberian waters. The southern populations of this complex, sympatric with S. pyrenaicus, show high genetic variability, diversity of forms and reproductive modes which create pathways that may allow for the establishment of a new species in the future. Here we report a contrasting view over the S. alburnoides complex: in the Mondego River basin (northern Portugal), nuclear "non-hybrid" and tetraploid forms are absent and a clearly impoverished genetic diversity is observed, contributing to a general scarcity of possibilities of generating novel genetic material. Moreover, the bisexual species involved in the maintenance of the complex in this basin (S. carolitertii) exhibits a considerably lower genetic variability, when compared with S. pyrenaicus. The observed differences suggest that, despite being originated by similar hybridization events and maintained by analogous reproductive mechanisms, different populations of the complex were exposed to distinct evolutionary constrains, which in some cases resulted in diversification and speciation while in others led to a compromising situation in terms of evolutionary potential. Additionally, and for the first time all forms were used in the calculation of genetic distances and diversity indices, widening the possibilities of analysis of the complex by allowing the inclusion of a large part of the available data, irrespective of ploidy level.

Animals↗

PubMed1991

In vitro effects of organophosphorus compounds on calmodulin activity.

In vitro effects of organophosphorus compounds (OP), such as malathion (M), methyl parathion (MP) and ethyl parathion (EP), on calmodulin (CaM) activity and its active conformation were studied to understand the mechanism(s) of neurotoxicity, since CaM is known to regulate Ca2+ transport and the enzymes involved in signal transduction and nucleotide metabolism. The biological activity of CaM was assessed as a measure of phosphodiesterase (PDE) stimulation. The effect of OP compounds on the active conformation of CaM was determined by studying the binding of fluorescence probes, namely N-phenyl-1-naphthylamine (NPN), and changes in dansyl-calmodulin fluorescence. Dansylated calmodulin was also used to study the effect of OP compounds on complex formation between CaM and PDE. All three OP compounds inhibited the CaM activity and its active conformation in a concentration-dependent manner. Malathion was less effective in comparison to EP and MP, with IC50 values of 37 microM, 34.5 microM and 32 microM, respectively, for CaM activity. EP and MP significantly altered NPN and dansyl-calmodulin fluorescence (50 microM concentrations of OP compounds), whereas M did not show any significant effect on NPN fluorescence. All these compounds significantly affected complex formation between the dansylated CaM and PDE. These results suggest that OP compounds may be interacting with CaM, altering its active conformation, and thus may be inhibiting its biological activity.

Binding Sites↗

PubMedDate not supplied

Epilepsy and teachers: a survey.

Teachers in five primary schools were surveyed for their knowledge and attitudes about epilepsy. An analysis of 113 teacher responses revealed knowledge deficits, especially regarding the prevalence of epilepsy, the future of children with the disorder and E.E.G. as an aid to diagnosis. Misconceptions regarding first aid were also common. More than two-thirds of the teachers believed that children with epilepsy have academic problems more often, although about half of the respondents were in favour of normal schools for such children. Most respondents recommended a teacher's career for these children in future but considered that of a bus driver, as unsuitable. Few teachers had attended any educational programme on epilepsy. Only about one-fifth of the teachers were confident in dealing with an epiletic child. Communication about epilepsy among the teachers, parents and doctors was virtually non-existent.

Adult↗