4 research outputs found
Evolutionary dynamics of Chlamydia trachomatis genome and identification of molecular patterns of hypothetical protein coding genes
The obligate intracellular bacterium Chlamydia trachomatis is a human pathogen of major public health significance. Strains can be classified into 15 main serovars (A to L3) that preferentially cause ocular infections (A-C), genital infections (D-K) or lymphogranuloma venereum (LGV) (L1-L3), but the molecular basis behind their distinct tropism, ecological success and pathogenicity is not welldefined.
Most chlamydial research demands culture in eukaryotic cell lines, but it is not known if stains become laboratory adapted.
By essentially using genomics and transcriptomics, we aimed to investigate the evolutionary patterns underlying the adaptation of C. trachomatis to the different human tissues, given emphasis to the identification of molecular patterns of genes encoding hypothetical proteins, and to understand the adaptive process behind the C. trachomatis in vivo to in vitro transition.
Our results highlight a positive selection-driven evolution of C. trachomatis towards nichespecific adaptation, essentially targeting host-interacting proteins, namely effectors and inclusion membrane proteins, where some of them also displayed niche-specific expression patterns. We also identified potential "ocular-specific" pseudogenes, and pointed out the major gene targets of adaptive mutations associated with LGV infections. We further observed that the in vivo-derived genetic makeup of C. trachomatis is not significantly compromised by its long-term laboratory propagation. In opposition, its introduction in vitro has the potential to affect the phenotype, likely yielding virulence attenuation. In fact, we observed a "genital-specific" rampant inactivation of the virulence gene CT135,
which may impact the interpretation of data derived from studies requiring culture.
Globally, the findings presented in this Ph.D. thesis contribute for the understanding of C.trachomatis adaptive evolution and provides new insights into the biological role of C. trachomatishypothetical proteins. They also launch research questions for future functional studies aiming toclarify the determinants of tissue tropism, virulence or pathogenic dissimilarities among C. trachomatisstrains
Investigations on surface damage by rolling contact fatigue in elastohydrodynamic contacts using artificial dents : the influence of grease composition
Tese de mestrado. Manutenção industrial. 2005. Faculdade de Engenharia. Universidade do Port
Homenagem Casa dos Estudantes do Império - 50 Anos | Testemunhos, Vivências, Documentos
Os textos incluídos nesta obra são transcrições das intervenções feitas
pelos participantes nas diversas sessões da homenagem à Casa dos Estudantes
do Império, realizadas entre 2014 e 2015. Estas intervenções
foram gravadas através de meios audiovisuais e posteriormente editadas
para efeitos de publicação. A presente edição segue a grafia do Acordo
Ortográfico, exceto nos casos em que os autores quiseram manter a antiga
grafia.CML – Câmara Municipal de Lisboa; Camões – Instituto da Cooperação
e da Língua; Fundação Calouste Gulbenkianinfo:eu-repo/semantics/publishedVersio
Characterisation of microbial attack on archaeological bone
As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved