Utilize este identificador para referenciar este registo: http://hdl.handle.net/10451/30405
Título: Understanding the cross-talk between microbiota, host fitness, and the environment using Egyptian mongoose (Herpestes ichneumon) as a model
Autor: Pereira, André da Conceição
Orientador: Cunha, Mónica Vieira
Palavras-chave: Sacarrabos
Microbiota intestinal
Identificação & Diferenciação
Carnívoros
Aptidão do Hospedeiro
Teses de mestrado - 2017
Data de Defesa: 2017
Resumo: Gut microbiota is the complex and diverse community of bacteria, archaea, fungi, protozoa, and viruses present in the gastrointestinal tract of animals. Once established, this ecosystem is relatively stable, but responsive to a variety of effects, namely host diet, health, genetics, sex, and reproductive status, and also the habitat. Increasing importance has been attributed to host gut-microbe interactions due to implications in the immune system and ecological features, such as behavior, however, the microbiota of many carnivores remains unknown. In this work, the gut microbiota of Egyptian mongoose, a medium-size mammalian carnivore, with opportunistic feeding behavior, ranging in distribution throughout the African continent, but also in Mediterranean Middle East, southern Turkey, and the Iberian Peninsula, was thoroughly investigated using a wide range culture-based approach. The aims of this work were: [1] the characterization of the core gut microbiota of Egyptian mongoose population; [2] the investigation of sex- and age class-related differences of gut microbiota; and [3] the analysis of the relationship between bio-environmental features and gut microbiota of these specimens. Fecal samples from ten males and ten females sampled in mainland Portugal were enriched in Buffered Peptone Water, in both aerobic and anaerobic conditions. Part of the enriched samples was pasteurized and inoculated into YCFA P solid medium, under both aerobic and anaerobic conditions. The remaining part was inoculated into YCFA under anaerobic conditions and into YCFA, MacConkey, PDA supplemented with chloramphenicol solid media, ESBL chromogenic medium, with and without antibiotic supplement, and Brilliance ESBL solid medium. Selected isolates were grouped into different morpho-physiological types (MT) based on Gram character, catalase and oxidase activities, and endospore formation. A bacterial isolate belonging to each MT, in each media, for each mammal host, was selected for molecular fingerprinting using Random Amplified Polymorphic DNA (RAPD) with M13 and PH primers. Strain relationships were analyzed by hierarchical numerical methods with Pearson correlation coefficient and Unweighted Pair Group Method with Arithmetic mean (UPGMA) clustering. One isolate from each cluster was randomly selected for 16S rDNA gene sequencing. Fungi isolates with different morphology were selected for genomic identification through Internal Transcribed Spacer (ITS) region sequencing. In this study, we generated for the first-time extended baseline information on the microbiome of mongoose, enabling the exploitation of microbial community differences between sexes and exploring the influence exerted by the biological and environmental context of each host in its microbiota signature. Looking at each individual host as a habitat with its own community, the MT-II, MT-VI, MTVII, MT-IX and MT-XI types may be considered the core gut microbiota community and the remaining morpho-physiological types can be considered part of the intra-specific individual microbiota community. Additionally, we perceived that the majority of individuals possess MT-II ESBL-producing bacteria. Higher microbial load was present in fecal samples from female hosts in rich medium under anaerobic conditions, both for total and sporobiota bacterial community. The bacterial microbiota of both males and females was dominated by Gram-positive bacteria, mainly of the phylum Firmicutes, with bacilli isolates prevailing, in particular, Enterococcus spp. and Bacillus spp. The growth of putative Escherichia coli was only registered in female host samples. The specimens analyzed in this study revealed high Proteobacteria/Bacteroidetes ratio, a feature that may be related to a carnivorous or scavenger dietary regime and with highly efficient energy harvest. Filamentous fungi were exclusively detected in fecal samples from male hosts and their genus identified as Pseudozyma and Naganishia (Basidiomycota phylum), Penicillium (Ascomycota phylum) and Mucor (Mucoromycota phylum). Although the number of surveyed specimens is limited, considerable similarity between adult and juvenile microbiota was found, which contrasted with sub-adult’s, probably due to higher proximity and interaction between the first two groups, since this species social behavior includes protection of the cubs and juveniles, leading to similar diet and easier host-to-host transmission of microbiota. This work sets the ground for more comprehensive studies on the microbiota of Mediterranean wild carnivores, including sympatric threatened species. Future studies using culture-independent methods will improve our knowledge of this species microbiome and lead to a better understanding of its bioecology.
Descrição: Tese de mestrado, Microbiologia Aplicada, Universidade de Lisboa, Faculdade de Ciências, 2017
URI: http://hdl.handle.net/10451/30405
Aparece nas colecções:FC - Dissertações de Mestrado

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