|
|
NIVB Meeting 2023
Hostomský, Zdeněk ; Vácha, R. ; Pichová, Iva ; Šímová, Šárka
NIVB Meeting 2023 – the second meeting of the National Institute of Virology and Bacteriology (NIVB) in Kutná Hora on 2. 10. – 5. 10. 2023 will be again after one year an opportunity to meet the participating teams, discuss excellent science, establish collaborations, and present the progress of the project to the members of the International Scientific Advisory Board. Thanks to funding from the Czech Economic Recovery Plan, a number of important results have already been published in high impact journals. Several networking workshops have been organized and scientific collaborations have been established. The meeting in Kutná Hora is therefore a summary of all that has happened in the project over the past year. The main goal of the NIVB is to facilitate cooperation between 30 participating research teams from 8 Czech research institutions, and this goal is gradually being achieved. The NIVB acts as a common communication platform to discuss the desired cooperation of the NIVB research teams, especially those that have not had much contact so far due to their inter-institutional, interdisciplinary or inter-regional distance.\nWe thank all the participants who contributed to the meeting with 30 oral presentations and 67 posters. The NIVB 2022 meeting had the ambition to launch a new series of annual meetings dedicated to virology and bacteriology, and NIVB 2023 fulfils this ambition and continues to aim to inform the wider scientific community about new developments, trends and issues in these disciplines.
|
|
|
Regulation of insect pheromone biosynthesis
Halmová, Martina ; Pichová, Iva (advisor) ; Valterová, Irena (referee)
Pheromones are compounds emitted by insects and vertebrates that specifically modulate the behaviour of the same species. Based on the role, pheromones are classified into different types such as releaser pheromones, primer pheromones, sex pheromones, aggregation pheromones, alarm pheromones and trail pheromones. Insect pheromones are volatile substances consisting mostly of alcohols, aldehydes, ketones, aromatic compounds and isoprenoids. Pheromone biosynthesis comprises fatty acid and isoprenoid metabolic pathways. Pheromone biosynthesis must be precisely regulated since the pheromone blend consists of a mixture of compounds with defined ratios and chemical structures. The main aim of this thesis is to summarize the published information about insect pheromone biosynthesis and regulation with a focus on pheromones involved in sexual communication. Attention will also be paid to the biotechnological potential of pheromones in targeted pest management with the utilisation of enzymes present in the biosynthesis of pheromones.
|
|
|
Functional analysis of insect fatty acyl-coenzyme A reductases and desaturases
Tupec, Michal ; Pichová, Iva (advisor) ; Šulc, Miroslav (referee) ; Doležel, David (referee)
Fatty acid-derived lipids are an important class of biomolecules. In addition to their primary role in cellular architecture, energy storage and signaling, they function in many other ways, e.g. as isolating or waterproof coatings, defense compounds and pheromones. Multiple enzymes mod- ify intermediates originating from fatty acid biosynthetic pathway, including desaturases (FADs) which synthesize unsaturated fatty acids, and reductases (FARs) which synthesize fatty alcohols. Functionally highly diversified fatty acyl-modifying enzymes from insects, one of the most abun- dant animals in the world, present a significant source for modern biotechnology of cell factories. This thesis summarizes available information on the FADs and FARs and describes the results which we have obtained while studying them. In bumblebees, we identified several FAR transcripts which are abundantly expressed in male pheromone-producing tissue. We then functionally characterized the corresponding enzymes in yeasts, and estimated their participation in the biosynthesis of fatty alcohols observed in the mark- ing pheromone-producing tissue. The studied enzymes reduce broad range of substrates, from short fatty acyls (e.g. C14) to very long ones (e.g. C26), from saturated fatty acyls to polyunsatu- rated ones. We also found...
|
|
|
Engineering and selection of protein binders recognising medically important cytokines
Huličiak, Maroš ; Schneider, Bohdan (advisor) ; Pichová, Iva (referee) ; Kukačka, Zdeněk (referee)
Protein engineering attracts more attention as a powerful tool of biotechnology and medicine. Small, engineered proteins derived from protein molecules of stable fold, the so called scaffolds, are potential replacements of supplements of more widely used antibodies. In this thesis, I introduce utilization of two scaffold molecules designed in our laboratory for development of stable and specific protein binders of high affinity. This thesis discusses the development of binders interacting with medically important human cytokines and their cellular receptors, interleukin-10, interleukin-28 receptor, and interleukin-9 receptor alpha. Recombinant cytokine and receptor proteins were expressed in eukaryotic cells in high yields and quality and served as molecular targets for selections using various display methods of directed evolution. We demonstrated that application of ribosome and yeast display methods or their unconventional combination in a newly developed integrated pipeline leads to successful generation of high affinity and specificity binders based on newly designed protein scaffolds called 57aBi and 57bBi.
|
|
|
Differentiation in Saccharomyces cerevisiae colonies
Čáp, Michal ; Palková, Zdena (advisor) ; Pichová, Iva (referee) ; Demnerová, Kateřina (referee)
Yeast colonies are, alongside to bacterial biofilms, multicellular communities formed by unicellular microorganisms. These specific communities differ in many ways from populations cultivated in planktonic cultivations. Gradients of nutrients, metabolic by- products and other factors are formed and preserved within these structures, which provides a basis for cellular differentiation. Current literature concerning these issues with emphasis on yeast colonies and biofilms is summarised in the Introduction of this work. Section Results then describes my contribution to the knowledge on the differentiation of the colonies of Saccharomyces cerevisiae as a model system for studying microbial multicellular structures. Previously described horizontal differentiation, i.e. differentiation between colony centre and margin, is further characterised with respect to ammonia signalling and stress resistance. The importance of genes conferring the cell`s oxidative stress resistance in colony differentiation was studied and it was concluded that not stress resistance but rather metabolic and other changes promoted by ammonia signal are important for colony differentiation and survival. A new type of colony differentiation - the horizontal, i.e. differentiation between upper and lower part of the colony, is...
|
|
|
EF-Tu PROTEIN DOMAINS Functions and Thermostability
Šanderová, Hana ; Jonák, Jiří (advisor) ; Pichová, Iva (referee) ; Mikulík, Karel (referee)
6 % The bacterial elongation factor Tu (EF-Tu) has been extensively studied for decades as it plays a key role in protein biosynthesis. It is a model, multifunctional GTP-protein. This protein is also in the centre of interest as a possible target for new antibiotics. Moreover, the high homology in structure and function makes EF-Tu proteins suitable for the studies of evolutionary relationships between organisms and for elucidation of the structural features of adaptation to various living conditions. Furthermore, since all known EF-Tu proteins are composed of three distinct domains, they can also serve as suitable models for the understanding of domain organization in proteins. One of the main research projects of the Department of Gene Expression at the Institute of Molecular Genetics AS CR, where I did my PhD studies, was the study of the primary structure, transcription regulation and functions of bacterial elongation factors Tu from Gram positive thermophilic bacterium Bacillus stearothermophilus and from Gram negative mesophilic bacterium Escherichia coli. In this work, we focused on the structure-function relationships between EF-Tu proteins and their domains. The domain effect had been before our studies tested mainly by truncated EF-Tu forms lacking one or two domains. In contrast, we decided to...
|
|
|
Mouse polyomavirus:The way of virus translocation to the cell nucleus and sensing of viral genomes by sensors of innate immunity
Soldatova, Irina ; Forstová, Jitka (advisor) ; Němečková, Šárka (referee) ; Pichová, Iva (referee)
To understand molecular mechanisms of individual steps of virus infection is a prerequisite for successful design of specific and effective antiviral drugs. Polyomaviruses, replicating in the cell nucleus, travel from plasma membrane to the endoplasmic reticulum (ER) in endosomes. However, it is not clear how they deliver their DNA genomes from ER to the nucleus. In this thesis, we found that partially disassembled virions of the Murine polyomavirus (MPyV) interact with importin β1 at around 6 hours post infection. Mutational disruption of the nuclear localization signal (NLS) of the major capsid protein, VP1, and/or common NLS sequence of the minor capsid proteins VP2 and VP3 did not affect the structure and composition of virions, but it resulted in decreased viral infectivity (up to 80%). Virions are thus released from ER to cytosol and translocate to the nucleus via nucleopores. Mutation analyses of NLSs of individual capsid proteins showed that MPyV virions can utilize VP1 and VP2/VP3 NLSs in concert. However, one functional NLS, either that of VP1 or VP2/3 seems to be sufficient for the delivery of VP1-VP2/3 complexes into the nucleus, although none of these proteins is delivered into the nucleus separately. Thus, the conformation of NLS regions given by the presence of all three capsid...
|
|
|
Study of evolution of insect pheromone biosynthetic fatty acyl desaturases
Buček, Aleš ; Pichová, Iva (advisor) ; Žďárek, Jan (referee) ; Doležel, David (referee)
Insects account for more than one million of described species with an ecological and economic impact disproportional to their minute body size. Among the factors which have contributed to their evolutionary success, insect secondary metabolites such as defensive compounds and chemical signals are regarded to play a major role. This thesis aims at uncovering the molecular mechanisms underlying evolution of ubiquitous insect secondary metabolites - sex pheromones (SPs), i.e. chemical signals mediating mate finding and mating between individuals of the same species. The thesis focuses on a class of oxidoreductase enzymes, membrane fatty acid desaturases (mFADs), which introduce double bonds into hydrocarbon chains of fatty acyls and thus produce precursors of unsaturated fatty acid- derived SPs. mFADs are involved in SP biosynthesis in e.g. moths (Lepidoptera), flies (Diptera), cockroaches and termites (Blattodea), wasps and bees (Hymenoptera) - some of the most species-rich insect orders. Since SPs are principal to species reproductive isolation, uncovering the molecular basis of insect SP biosynthesis holds promises to contribute to answering fundamental questions concerning the insect ecology and evolution. The insect mFADs with diverse enzymatic specificities also represent a naturally available...
|
|
|
Studies of S. cerevisiae BR-S strain with deletion of SIR2 gene
Novotná, Pavla ; Kuthan, Martin (advisor) ; Pichová, Iva (referee)
Yeasts are unicellular eukaryotic microorganisms, capable of forming of organised multicellular communities, the colonies. Many yeast strains possess a characteristic colony morphology under defined living conditions. Another feature typical for many feral and pathogenic yeast strains is the ability to switch their morphotype. This phenomenon, called the phenotypic switching, contributes to a rapid adaptation to the changing harmful environment and is often connected with changes of the stress resistance or with the changes of virulence of pathogenic yeasts. Phenotypic switching can be observed even in non-pathogenic yeast Saccharomyces cerevisiae. The strain BR-F, isolated from nature, switches under laboratory conditions from fluffy to smooth morphology of the strain BR-S. This phenotypic switch is accompanied by broad changes in the phenotype. Transcriptome analyses of the strains BR-F and BR-S have shown, among others, changes in expression of the subtelomeric genes that are under control of the histone acetylases and deacetylases. My work was aimed to the histone deacetylase Sir2p, which could influence the phenotypic switching in Saccharomyces cerevisiae. The sir2 deletion mutant of the strain BR-S, prepared in our laboratory, was used for my studies. The results show, that the strain BR-S...
|
|
|
Physiological role of Na+/H+ antiporters in yeast cells
Zahrádka, Jaromír ; Sychrová, Hana (advisor) ; Obšilová, Veronika (referee) ; Pichová, Iva (referee)
3 Abstract Yeast Saccharomyces cerevisiae belongs to important models for alkali-metal-cation homeostasis research. As other cells, certain intracellular content of K+ is necessary for S. cerevisiae, but Na+ or other alkali metal cations (Li+ , Rb+ ) are toxic for yeast cells. Uniporters Trk1 and Trk2 are responsible for K+ accumulation, while efflux of Na+ , Li+ , Rb+ and K+ is ensured by Ena ATPases, Na+ (K+ )/H+ antiporter Nha1 and K+ specific channel Tok1. Several regulators of K+ (Na+ ) transporters are already known, but reciprocal regulation between transporters and overall picture of the maintenance of alkali-metal-cation homeostasis is still unclear. In this work, K+ circulation (simultaneous uptake and export of K+ ) was shown to be important in alkali-metal-cation homeostasis maintenance. K+ circulation is maintained using reciprocal regulation and interactions between K+ exporters and importers. Though obtained results showed that the alkali-metal-cation homeostasis and associated physiological parameters (e.g. membrane potential, cell size, salt sensitivity) are strain specific, Nha1p was verified to be important for cell survival in ever-changing natural environment. Furthermore, two novel positive regulators of Nha1p activity were found, 14-3-3 proteins and Cka1 kinase. 14-3-3 proteins...
|
guest ::
RSS feed.