Explicit methods for Hilbert modular forms

We exhibit algorithms to compute systems of Hecke eigenvalues for spaces of Hilbert modular forms over a totally real field. We provide many explicit examples as well as applications to modularity and Galois representations.

Circulating Antigens Levels in Different Clinical Forms of the Schistosoma mansoni Infection

With the aim to evaluate the circulating cathodic antigen (CCA) levels in relation to the different clinical phases of Schistosoma sp. infection a sandwich ELISA using monoclonal antibody 5H11 was performed. The sera of three groups of 25 Brazilian patients with acute, intestinal and hepatosplenic forms of S. mansoni infection were tested and compared to a non-infected control group. Patients and control groups were matched for age and sex and the number of eggs per gram of feces was equally distributed among the three patient groups. Sensitivity of 100%, 72%, 52% of the assay was observed for the intestinal, hepatosplenic and acute toxemic groups respectively. The specificity was 100%. Intestinal and hepatosplenic groups presented CCA levels significantly higher in comparison to those observed for acute patients (F-ratio = 2,524; p = 0.000 and F-ratio = 6,314; p = 0.015 respectively). There was no significant difference of CCA serum levels between hepatosplenic and intestinal groups (F-ratio = 1,026; p = 0.316).

Features of host cell invasion by different infective forms of Trypanosoma cruzi

Through its life cycle from the insect vector to mammalian hosts Trypanosoma cruzi has developed clever strategies to reach the intracellular milieu where it grows sheltered from the hosts' immune system. We have been interested in several aspects of in vitro interactions of different infective forms of the parasite with cultured mammalian cells. We have observed that not only the classically infective trypomastigotes but also amastigotes, originated from the extracellular differentiation of trypomastigotes, can infect cultured cells. Interestingly, the process of invasion of different parasite infective forms is remarkably distinct and also highly dependent on the host cell type.

Age-dependent gain of alternative splice forms and biased duplication explain the relation between splicing and duplication.

We analyze here the relation between alternative splicing and gene duplication in light of recent genomic data, with a focus on the human genome. We show that the previously reported negative correlation between level of alternative splicing and family size no longer holds true. We clarify this pattern and show that it is sufficiently explained by two factors. First, genes progressively gain new splice variants with time. The gain is consistent with a selectively relaxed regime, until purifying selection slows it down as aging genes accumulate a large number of variants. Second, we show that duplication does not lead to a loss of splice forms, but rather that genes with low levels of alternative splicing tend to duplicate more frequently. This leads us to reconsider the role of alternative splicing in duplicate retention.

The Mental Health Order (Northern Ireland) 1986 - prescribed forms (PDF 169 KB)

The Mental Health Order (Northern Ireland) 1986 - prescribed forms.

GP Appraisal Forms 1-6 Feb 06 (PDF 52 KB)

GP Appraisal Updated Forms 1-6 (February 2006)

Morphological comparison of axenic amastigogenesis of trypomastigotes and metacyclic forms of Trypanosoma cruzi

Amastigogenesis occurs first when metacyclic trypomastigotes from triatomine urine differentiate into amastigotes inside mammalian host cells and a secondary process when tissue-derived trypomastigotes invade new cells and differentiate newly to amastigotes. Using scanning electron microscopy, we compared the morphological patterns manifested by trypomastigotes and metacyclic forms of Trypanosoma cruzi during their axenic-transformation to amastigotes in acidic medium at 37°C. We show here that in culture MEMTAU medium, secondary and primary axenic amastigogenesis display different morphologies. As already described, we also observed a high differentiation rate of trypomastigotes into amastigotes. Conversely, the transformation rate of in vitro-induced-metacyclic trypomastigotes to amastigotes was significantly slower and displayed distinct patterns of transformation that seem environment-dependent. Morphological comparisons of extracelullar and intracellular amastigotes showed marked similarities, albeit some differences were also detected. SDS-PAGE analyses of protein and glycoprotein from primary and axenic extracelullar amastigotes showed similarities in glycopeptide profiles, but variations between their proteins demonstrated differences in their respective macromolecular constitutions. The data indicate that primary and axenic secondary amastigogenesis of T. cruzi may be the result of different developmental processes and suggest that the respective intracellular mechanisms driving amastigogenesis may not be the same.

RadA protein from Archaeoglobus fulgidus forms rings, nucleoprotein filaments and catalyses homologous recombination.

Proteins that catalyse homologous recombination have been identified in all living organisms and are essential for the repair of damaged DNA as well as for the generation of genetic diversity. In bacteria homologous recombination is performed by the RecA protein, whereas in the eukarya a related protein called Rad51 is required to catalyse recombination and repair. More recently, archaeal homologues of RecA/Rad51 (RadA) have been identified and isolated. In this work we have cloned and purified the RadA protein from the hyperthermophilic, sulphate-reducing archaeon Archaeoglobus fulgidus and characterised its in vitro activities. We show that (i) RadA protein forms ring structures in solution and binds single- but not double-stranded DNA to form nucleoprotein filaments, (ii) RadA is a single-stranded DNA-dependent ATPase at elevated temperatures, and (iii) RadA catalyses efficient D-loop formation and strand exchange at temperatures of 60-70 degrees C. Finally, we have used electron microscopy to visualise RadA-mediated joint molecules, the intermediates of homologous recombination. Intriguingly, RadA shares properties of both the bacterial RecA and eukaryotic Rad51 recombinases.

Detection of amastigote-like forms in the valve of Phlebotomus papatasi infected with Leishmania major

A massive and homogeneous amount of amastigote-like forms was detected in the stomodeal valve (SV) and the thoracic mid-gut (TMG) of Leishmania major-infected Phlebotomus papatasi, which received a second blood meal 13 to 21 days post-infection on healthy anaesthetized hamsters. After re-feeding, the infected sand flies were dissected out to examine the morphology of the parasite in SV, TMG and the abdominal mid-gut (AMG). Different promastigote forms were seen in the infected flies. Among these included typical promastigotes (nectomonads and haptomonads), paramastigotes, metacyclic promastigotes and, in some samples, the here-reported amastigote-like forms. The Leishmania amastigote-like forms were detected in the SV of sand flies with 14, 18 and 21 days of infection as well as in the TMG at 13 and 18 days post-infection. However, the amastigote-like forms were not detected in the AMG. Factors such as the acidic pH predominating the TMG and the SV, as well as the temperature of the ingested blood, among others, are suggested as contributing to the transformation of the typical promastigotes into the amastigote-like forms. The significance of this finding is discussed and the possible biological advantage for transmission of Leishmania is considered.