Conferências do cE3c

Sala 2.2.14, FCUL, Lisboa

Por Klaus Harms e João A. Gama (“The Arctic University of Norway", Tromsø, Norway).


How bacteria feed and breed on fragmented, random environmental DNA | 11h00-11h45
Klaus Harms
“The Arctic University of Norway", Tromsø, Norway

Bacteria propagate by cell division, resulting in offspring cells that are, save for mutations, genetically identical with their ancestors. However, bacteria can dramatically increase genetic diversity through so-called horizontal gene transfer (HGT). In the course of HGT, external intraspecies DNA that reaches the cytoplasm can be recombined with the cellular DNA, allowing uncoupled mixing of alleles and resulting in population structures that resemble those of sexual organisms. More rarely, HGT leads to acquisition of foreign DNA that contains novel genetic information. In an evolutionary perspective, such new DNA enables bacteria to develop novel traits and to conquer previously inaccessible environmental niches.
HGT can be conferred through transduction, conjugation, transformation and, less frequently, through a number of further, less well characterized processes. Natural transformation is the active uptake of DNA from the environment by bacteria and its subsequent integration into the genome. A prerequisite for naturally transformable bacteria is the initiation of a physiological state named competence for DNA uptake.
DNA is released into the environment mostly by dead organisms, but some bacteria also actively excrete DNA. Under many environmental conditions, free DNA is quickly degraded by fragmentation and further chemical damages such as deamination, base loss, or cross-links with organic molecules. Moreover in complex environments, heterologous DNA vastly outnumbers the available homologous DNA. On the other hand, even heavily fragmented, chemically damaged, and fragmentary heterologous DNA can still transform bacteria, but the result is not acquisition of genes, but mutational modification of the bacterial genomic DNA. In this talk, I describe the mechanisms, benefits, and constraints of natural transformation by such DNA substrates.


Why some E. coli strains are not good plasmid hosts | 11h45-12h30
João A. Gama
“The Arctic University of Norway", Tromsø, Norway

Escherichia coli comprises strains ranging from commensal to pathogenic. Some of them may harbour accessory genetic elements such as plasmids, which play an important role in bacterial adaptation. However, plasmids can be lost in the absence of selection, as shown with model organisms. We studied the effects of a clinical plasmid encoding antibiotic resistance against carbapenems (last resort antibiotics) on a sample of clinical E. coli representing different sequence types (ST).
We aim to understand how different E. coli strain backgrounds face plasmid acquisition.
Most strains maintained the plasmid for ≈300 generations. Compared to other strains, ST73 strains grew slower when acquiring the plasmid (plasmid fitness cost). Moreover, plasmid conjugative transfer from the original isolate was particularly lower into ST73 strains. In agreement, analysis of E. coli genomes revealed lower frequency of plasmids in ST73 genomes than in the other STs studied. Defense mechanisms against horizontal gene transfer, such as restriction-modification systems, could be responsible for this behaviour. Comprehensive bioinformatical analysis showed that type III restriction-modification systems are more frequently present in ST73 genomes. Furthermore, there is a negative correlation between plasmid carriage and presence of type III restriction-modification systems among ST73 genomes.
Overall, these data may explain, at least in part, why molecular epidemiology studies suggest that ST73 is less associated with antibiotic resistance determinants.

11h00-12h30
cE3c - Centro de Ecologia, Evolução e Alterações Ambientais

Seminário de Tese no âmbito do Doutoramento em Biologia e Ecologia das Alterações Globais.

Colóquio de Matemática, por Carlos André (Departamento de Matemática | Ciências ULisboa e CEAFEL-Ciências - Centro de Análise Funcional, Estruturas Lineares e Aplicações).

Logótipo do evento, sobre um fundo branco

Understanding plant water relations at several scales under climate change is the theme of the XV Portuguese-Spanish Water relations Symposium: “Water relations under climate change: from genes to ecosystem”.

Seminário Helena Avelar de Astronomia e Astrologia Antiga, por Martin Gansten (Lund University e Umeå University).

Logótipos ERC e EIC

A sessão visa apresentar os programas ERC e EIC e as potenciais sinergias que podem ser estabelecidas entre ambos.

Fotografia de candidatos, acompanhada do título "M23 2022|2023"

A ULisboa promove o Dia Aberto M23, um evento que pretende aproximar o público adulto do meio universitário.

In this course, we promote a multidisciplinary approach presenting the most recent findings on the topic and challenging the traditional way of considering symbiotic associations as exceptions and not as the rule.

The goal of this course is to provide to the participants with current and practical knowledge on urban ecology, including ecological and social aspects.

Neste encontro, vamos descobrir as potencialidades da utilização do Jamboard - um quadro branco digital gratuito da Google - em trabalhos colaborativos.

Nesta formação, aprenderemos a criar apresentações dentro do Mentimeter, a criar diferentes tipos de slides e a selecionar as configurações mais adequadas aos objetivos pedagógicos.

Nesta formação, iremos abordar as diferentes etapas do processo de planificação de unidades curriculares e refletir conjuntamente em boas práticas sustentadas pela investigação.

Fotografia de placa de identificação de zona de plantação de vinha

Candidaturas até 28 de fevereiro de 2022.

This course aims to explore ways of communicating science to non-specialized audiences, such as policy makers, industry, general public (including students and teachers), through their engagement and participation in citizen science activities.

O evento pretende juntar técnicos, investigadores, estudantes, produtores, industriais e demais agentes da fileira, contribuindo para a atualização de dados sobre o setor e a partilha de conhecimentos sobre as potencialidades da flora portuguesa, para além, das condições edafoclimáticas nacionais que potenciam produtos de elevada qualidade.

This course introduces the field of island biogeography, a discipline that has long influenced other research areas such as macroecology, community ecology, evolution and conservation biology.

Scientists, as the main actors in the production of scientific knowledge, have the responsibility of having an active voice in communicating this knowledge – and that can be achieved for example by a conscious use of the communication tools at their disposal and a better articulation with journalists, among other means.

This course aims at providing students with basic knowledge of R programming, allowing them to manipulate and visualize data with R.

This course aims at providing students with statistical knowledge and tools to manipulate, analyze and visualize biological data with R. It also includes an introduction to modeling, simulations and Bayesian statistics.

Under the general framework of Global Change Ecology, the goal of this course is to provide the participants with the most recent and practical knowledge on the use of Functional Diversity.

The course provides essential skills and knowledge that enable the participants to develop climate change adaptation strategies.

The objective of this course is to provide participants with basic knowledge on a) the fundamental aspects of experimental design and b) workflows, platforms and tools to increase reproducibility at all scientific levels.

This is a mostly practical course offering an overview on different community ecology and macroecological methods and software. These will include all steps of a research project, from the optimal sampling of communities to process inference from large-scale patterns of taxon, phylogenetic and functional diversity.

This course aims to walk through the grounds of modern botany studies, covering subjects that have been excluded from most academic curricula.

The course aims at enabling the participants to use different methods to measure the impacts of pollutants on ecosystems. Basic knowledge will be provided through theoretical and practical lessons on how to select and use the most suitable metrics based on the analysis of multiple compartments of the ecosystems.

This course offers an overview of the different ways to measure biodiversity, and provides tips for the stratification of primary biodiversity data and the construction of variables that describe its various facets. It also includes an in-depth review of the different types of data used to measure biodiversity and their problems and limitations.