This thesis pioneers diatom molecular identification and quantification through genome-scale methods, with four key aims: (i) reviewing DNA/RNA sequencing methods in aquatic biomonitoring to... Show moreThis thesis pioneers diatom molecular identification and quantification through genome-scale methods, with four key aims: (i) reviewing DNA/RNA sequencing methods in aquatic biomonitoring to highlight their strengths and limitations; (ii) unraveling the evolutionary history of Nitzschia palea and investigating species delimitation within the species complex; (iii) identifying silica genes in N. palea for insights into ecology and evolution; and (iv) assessing a genome-scale quantification method for diatom biomonitoring to improve accuracy and scalability in estimating abundances. The review (Chapter 2) emphasizes disparities between molecular and morphology-based approaches and introduces the challenges in accurately estimating species abundances. Chapter 3 explores N. palea's evolutionary history using transcriptome data and reveals reticulate evolutionary patterns resulting in a putative hybrid between populations with different morphological characteristics. Chapter 4 pinpoints silica genes in N. palea and reveals variations among different populations that may lead to differences in silica metabolism. Chapter 5 introduces a genome-scale quantification approach that provides a promising alternative for molecular diatom biomonitoring due to its improved taxonomic resolution and quantification accuracy. In summary, this thesis underscores that genome-scale methods' have a critical role in diatom identification and quantification, and in advancing our understanding of microalgal taxonomy, ecology, and evolution. Show less
β-Lactamases are enzymes that can break down β-lactam substrates, such as antibiotics, preventing the use of these antibiotics for the treatment of various infectious diseases. However, some... Show moreβ-Lactamases are enzymes that can break down β-lactam substrates, such as antibiotics, preventing the use of these antibiotics for the treatment of various infectious diseases. However, some compounds, β-lactamase inhibitors, can block these enzymes allowing for possible treatments using a combination of antibiotic and inhibitor. BlaC is the β-lactamase of Mycobacterium tuberculosis, the bacteria that cause tuberculosis, and is used as a model for protein evolution. To understand if and how BlaC can develop resistance against certain inhibitors we studied the evolutionary adaptability of this enzyme. We used laboratory evolution and various biochemical techniques to characterize several mutations in BlaC and subsequently tested the effect of combining mutations. One of the findings is that BlaC can easily become less sensitive to the inhibitor sulbactam by partially blocking the entrance to the active site. Interestingly, this was accompanied by increased sensitivity to another inhibitor, avibactam, that could not be compensated for by other mutations.Generally, Escherichia coli bacteria are used to test the effects of BlaC variants in cells, as they are easy and safe to use in the lab. We show that results obtained for E. coli can be extrapolated to conditions that resemble tuberculosis disease in humans: the M. marinum infection model of zebrafish. All these findings are of interest for the future development of combination therapies to treat tuberculosis. Show less
The largest genus within the Phyllanthaceae family is a group called Phyllanthus L. Recent studies have shown, that Phyllanthus is paraphyletic with the genera Glochidion, Breynia and Synostemon... Show moreThe largest genus within the Phyllanthaceae family is a group called Phyllanthus L. Recent studies have shown, that Phyllanthus is paraphyletic with the genera Glochidion, Breynia and Synostemon nested within it. In this thesis, I study the evolution and systematics of Phyllanthus and how to solve the apparent paraphyly. First we explore past morphological subgroups to come to a subdivision, which was tested using molecular phylogenetics. Several species of Phyllanthus are also used in traditional medicine and by utilizing the living collections of the Hortus botanicus Leiden, we tested for antibacterial and antifungal bioactivity. The phylogeny resulting from this study is used to study the historical biogeography and diversification of the tribe and to propose a new classification where Phyllanthus is separated into several smaller genera. Show less
The explosive radiation and diversification of the advanced snakes (superfamily Colubroidea) was associated with changes in all aspects of the shared venom system. Morphological changes included... Show moreThe explosive radiation and diversification of the advanced snakes (superfamily Colubroidea) was associated with changes in all aspects of the shared venom system. Morphological changes included the partitioning of the mixed ancestral glands into two discrete glands devoted for production of venom ormucous respectively, as well as changes in the location, size and structural elements of the venom-delivering teeth. Evidence also exists for homology among venom gland toxins expressed across the advanced snakes. However, despite the evolutionary novelty of snake venoms, in-depth toxin molecular evolutionary history reconstructions have been mostly limited to those types present in only two front-fanged snake families, Elapidae and Viperidae. To have a broader understanding of toxins shared among extant snakes, here we first sequenced the transcriptomes of eight taxonomically diverse rear-fanged species and four key viperid species and analysed major toxin types shared across the advanced snakes. Show less
Taxonomy as a science has accumulated data and knowledge for more than 250 years. The quality and usefulness of the facts recorded in taxonomic literature has greatly improved from the early... Show moreTaxonomy as a science has accumulated data and knowledge for more than 250 years. The quality and usefulness of the facts recorded in taxonomic literature has greatly improved from the early descriptive texts to the modern data-rich, hypothesis-driven works. Our work illustrates the application of some of the “e-taxonomic” tools and the “New Taxonomy” thinking explored in the introduction. Here, we analyzed specimen data contained in legacy taxonomic literature in Chapters 2 and 3—to observe species distribution of one spider group and genital evolution, respectively—and also explored an integrative perspective that involves describing new taxa and testing phylogenetic hypotheses using molecular and morphological data, as done in Chapter 4 and 5. Show less
Balsaminaceae is a diverse plant family characterized by a huge floral morphological diversity. Its classification has changed many times throughout the taxonomic history of the group, owing to... Show moreBalsaminaceae is a diverse plant family characterized by a huge floral morphological diversity. Its classification has changed many times throughout the taxonomic history of the group, owing to the emphasis on particular diagnostic characters. This suggests that patterns of character evolution are labile and do not contain much phylogenetic signal. This appears particularly prevalent among floral characters, suggesting that floral evolution and pollination ecology may be important drivers of diversification in the family. Further complications in taxonomy arise from the fact that one of the two genera of the family, Impatiens, has a very large number of species, and that it is distributed across several continents. This has led to a lack of taxonomic effort, especially those regions where very few studies have been done, despite large species diversity. In this thesis, I filled particular gaps in knowledge of Balsaminaceae, focusing on issues related to the Southeast Asian region, including the taxonomic revision of this family in Myanmar (Chapter 2-4), molecular phylogeny and morphological character evolution of Impatiens sect. Semeiocardium (Chapter 5), comparative pollination biology of 7 sympatric Impatiens species in Thailand (Chapter 6), and evolution of corolla symmetry and pollination system of this family (Chapter 7). Show less
Radio observations provide a unique view of black holes in the Universe. This thesis presents low frequency radio images and uses the radio sources in those images to study the evolution of black... Show moreRadio observations provide a unique view of black holes in the Universe. This thesis presents low frequency radio images and uses the radio sources in those images to study the evolution of black holes and galaxies through the age of the Universe. Show less
Natural zebra finch song contains heterogeneity in the relative distribution of element types across 13 populations worldwide, but compared between individuals it contains relatively little... Show moreNatural zebra finch song contains heterogeneity in the relative distribution of element types across 13 populations worldwide, but compared between individuals it contains relatively little structural constraints or rules in the order of elements. In contrast, from a perception point of view, zebra finches are able to detect differences in song structure and are able to learn rules to generalize these regularities to new element types in some instances, a hallmark of human language. This ability might seem conflicting with the absences of clear structural rules in their own natural songs, but it might be that these rule learning/detection mechanisms operate in a more general cognitive context, which has also been suggested for some mechanisms found in human artificial language learning. Show less
Evolution and Interaction are two processes in Computer Science that are used in many algorithms to create, shape, find and optimize solutions to real world problems. Evolution has been very... Show moreEvolution and Interaction are two processes in Computer Science that are used in many algorithms to create, shape, find and optimize solutions to real world problems. Evolution has been very successfully applied as a pow-erful tool to solve complex search problems in fields ranging from physics, chemistry and biology all the way to commercial application such as aircraft fuselage design and civil engineering grading plans. Defining interaction is a big part of algorithm design. Not only defining the inputs and outputs of an algorithm but for a complex algorithm the interactions inside of an al- gorithm are as important. This thesis will concentrate on where Evolution overlaps Interaction. It will show how evolution can be used to evolve in- teraction, how the interaction inside an evolutionary algorithm impacts its performance and how an evolutionary algorithm can interact with humans. By touching on these three forms of overlap this thesis tries to give insight into the world of evolution and interaction Show less
This thesis comprises elementary work on the evolution of ageing. The issue of ageing, and especially of starvation resistance, has been approached from both the environmental and the genetic sides... Show moreThis thesis comprises elementary work on the evolution of ageing. The issue of ageing, and especially of starvation resistance, has been approached from both the environmental and the genetic sides that are of relevance to the issue. Therewith, this study has a broad orientation, varying from ecophysiology to selection experiments, mutant analysis and sate of the art microarray gene expression analysis. All this work was performed on Drosophila melnogaster, the fruit fly, and was put in an integrative context with human ageing. Show less
