Biblioteca
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The Library of FMV supports students, researchers and teachers of FMV and external users in the provision and search of books, periodicals and articles necessary for their studies. It has around 42.800 books and 1.670 periodicals, among other materials like microfilms and CD/ROMs.
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Browsing Biblioteca by Subject "16S rRNA"
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- Avaliação do microbioma fecal em cães com Hiperadrenocorticismo espontâneoPublication . Gomes, Alexandre Carvalho; Pomba, Maria Constança Matias Ferreira; Leal, Rodolfo Assis OliveiraO hiperadrenocorticismo espontâneo (HAC) é uma endocrinopatia que se caracteriza por um excesso de glucocorticoides endógenos, produzidos pela glândula adrenal. O HAC pode ser de vários tipos, sendo os dois tipos mais frequentes: Hiperadrenocorticismo hipofisário-dependente, quando o excesso de cortisol é produzido por um aumento sérico da hormona ACTH, geralmente secundário a um tumor na hipófise, ou o Hiperadrenocorticismo adrenal-dependente, quando o excesso de cortisol é devido a uma neoplasia funcional da adrenal, em que esta sintetiza de forma aumentada esta hormona. O diagnóstico de HAC é difícil, uma vez que os vários testes funcionais (teste de estimulação com ACTH e o teste de supressão com dexametasona em baixa dose) não têm 100% de sensibilidade, nem de especificidade, para além de que podem ser afetados, por fatores extrínsecos como o stress. Por isso, para além dos testes funcionais, é importante tentar identificar outros potenciais biomarcadores que permitam num futuro próximo auxiliar no diagnóstico desta afeção. Estudos recentes demonstraram que o microbioma entérico tem um papel essencial nos processos fisiológicos e imunológicos do hospedeiro e é frequentemente alterado com a dieta, ambiente, intervenções médicas, doenças metabólicas, imunológicas e neoplásicas. O objetivo deste estudo consistiu em avaliar se o hiperadrenocortismo apresentava alguma influência no microbioma destes animais. Foi realizado um estudo prospetivo que incidiu na comparação do microbioma fecal de cães saudáveis (N=9), com cães com cães com Hiperadrenocorticismo espontâneo (N=9). Foi realizada extração de DNA fecal e amplificada a região V4 do gene 16S rRNA, seguindo-se de sequenciação com Illumina MiSeq. Após a realização da análise bioinformática, utilizando o QIIME2 (versão 2019.10) obteve-se um aumento significativo das abundâncias relativas do filo Proteobacteria, especialmente da família Enterobacteriaceae, mas também da família Pseudomonadacea e do género Campylobacter. Também foi obtida uma diminuição do filo Bacteroidetes, especialmente o género Prevotella e o género Bacteroides. Relativamente ao filo Firmicutes, registou-se uma diminuição da família Erysipelotrichaceae e dos géneros Robinsoniella, Ruminococcus e da família Clostridiaceae. Contudo, ainda relativamente a este filo, registou-se um aumento da classe Bacilli, especialmente o género Streptococcus. Tanto quanto é do nosso conhecimento, este é o primeiro estudo a descrever e comparar o microbioma fecal de cães saudáveis com cães com hiperadrenocorticismo espontâneo, comprovando que o hipercortisolismo endógeno influencia a composição deste.
- Changes in the feline gut microbiota associated to Toxocara cati infectionsPublication . Duarte, Ana Lúcia Miranda; Cantacessi, Cinzia; Carvalho, Luís Manuel Madeira deInvestigations of the relationships between the gut microbiota and gastrointestinal parasitic nematodes are attracting growing interest by the scientific community. These studies have however been carried out mainly in humans and experimental animals, while knowledge of the make-up of the gut commensal microbiota in presence or absence of infection by parasitic nematodes in domestic animals is limited. In this study, we investigate the qualitative and quantitative impact that infections by a widespread parasite of cats (i.e. Toxocara cati) exert on the gut microbiota of feline hosts. The faecal microbiota of cats with patent infection by T. cati (= Tc+), as well as that of negative controls (= Tc-) was examined via high-throughput sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene, followed by bioinformatics and biostatistical analyses of sequence data. A total of 2,325,366 useable high-quality sequences were generated from the faecal samples analysed in this study and subjected to further bioinformatics analyses, which led to the identification of 128 OTUs and nine bacterial phyla, respectively. The phylum Firmicutes was predominant in all samples analysed (mean of 53.0%), followed by the phyla Proteobacteria (13.8%), Actinobacteria (13.7%) and Bacteroidetes (10.1%). Among others, bacteria of the order Lactobacillales, the family Enterococcaceae and genera Enterococcus and Dorea showed a trend towards increased abundance in Tc+ compared with Tc- samples, while no significant differences in OTU richness and diversity were recorded between Tc+ and Tcsamples (P = 0.485 and P = 0.581, respectively). However, Canonical Correlation and Redundancy Analyses were able to separate samples by infection status (P = 0.030 and P = 0.015, respectively), which suggests a correlation between the latter and the composition of the feline faecal microbiota.
- Gut microbiome in healthy dogs and catsPublication . Aboim, Catarina Fânzeres de Sousa Pinto; Pomba, Maria Constança Matias Ferreira; Leal, Rodolfo OliveiraRecent studies show that the gut microbiome contributes to the vital physiologic and immunologic processes and is influenced by external factors such as diet, environment, medical interventions, and disease states. In this study, we describe the gut microbiome of healthy dogs and cats, from households and shelters, contributing for a better understanding of the effect that environment can have on it. The samples were collected between 2016 and 2017 and consisted of a household group (N=38, N=26 dogs and N=12 cats) and a shelter group (N=62, N=51 dogs and N=11 cats). DNA extraction was done directly from the faeces and the V4 region of the 16S rRNA gene was amplified, followed by sequencing using Illumina MiSeq. Raw sequences were treated using QIIME2 and Greengenes database was chosen for taxonomic classification alignment at 99% similarity. SAS statistical software was used, a p-value < 0.05 was considered. The Principal Coordinate Analysis plot demonstrated that the feline and canine microbiomes were well separated, as well as the household dog samples and the shelter dog samples, meaning that there is a difference in the gut microbiome between these groups. The same conclusion was not observed for the cat samples. The phyla Firmicutes and Bacteroidetes were the predominant ones in both species. For the dog samples, there was no difference between the two groups in Firmicutes and Bacteroidetes phyla (p>0.05), but the phyla Fusobacteria and Proteobacteria were in higher percentages in the shelter group (p<0.05). To our knowledge, this is the first study that describes and compares the gut microbiome composition of healthy household and shelter dogs and cats. This study demonstrates that the environment where animals are born and grow, as well as the amount of contact they have with humans, may have a great influence in their gut microbiome.