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Phylogenetic Position of Genus Polymastix and Its Prokaryotic Symbionts
Kubánková, Aneta ; Hampl, Vladimír (advisor) ; Kolísko, Martin (referee)
Polymastigidae is one of the five families of oxymonads (Metamonada, Preaxostyla). It includes small flagellates inhabiting the digestive tract of insects. Recently obtained molecular phylogenetic data have questioned the monophyly of this group. The type genus of the family Polymastigidae is Polymastix. The phylogenetic position of this genus has not been studied yet, although this information could significantly help to clarify the relationships within this group. This work provides the first sequence data of this genus, which we have obtained using a single- cell genome amplification and subsequent whole genome sequencing on Illumina HiSeq X Ten (Macrogene) from three individuals of P. melolonthae inhabiting the posterior hindgut of crane fly larvae. Phylogenetic analysis based on the gene for 18S rRNA, EF-1α and HSP90 yielded several roughly equally probable hypotheses about the position of this genus within Oxymonadida. The first of them places the genus Polymastix in a close proximity to the genus Streblomastix, according to the second hypothesis, Polymastix is sister to Termitimonas travisae. A characteristic feature of this protist is ectosymbiotic bacteria attached to its surface. These were necessarily amplified and sequenced together with their hosts, which allowed us to obtain sequence...
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Multilokusová charakteristika symbiontů entomopatogenních hlístovek rodu \kur{Steinernema}
FAKTOROVÁ, Lucie
During the evolution some groups of organisms have become coevolutionary associated with other groups, as is the case of host symbiont systems. To explore coevolutionary history of hosts and their associated symbionts, phylogenetic reconstruction of symbionts and phylogenetic reconstruction of hosts are usually compared. Coevolution is described by coevolutionary events (cospeciation, host switch, duplication, failure to diverge events and linage sorting events). The aim of this work was to test the suitability of MLST method for the complex of entomopathogenic nematodes from the genus Steinernema (with detailed analysis of Steinernema feltiae) and their symbiotic bacteria Xenorhabdus bovienii and subsequently use cophylogenetic comparative analysis to determine their level of cospeciation.
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Antimicrobial activity of bacteria isolated from Pectinatella magnifica
Holečková, Karolína ; Vlková, Eva (advisor) ; Geigerová, Martina (referee)
The thesis is comprised of two parts. The first part is dedicated to the literature search, overview, which is focuses on the summary of information that was previously found not only about the life and reproduction of freshwater bryozoan Pectinatella magnifica, but also the importance of marine species bryozoans. Furthermore, importance of antimicrobial active substances and most commonly used laboratory methods for determination of microbial activity are shown in the report characteristics. The aim of the review was to summarize the most important facts underlying the experimental hypothesis described in the second part of this work. The reason for testing the antimicrobial activity of symbiotic bacteria isolated from Pectinatella magnifica is that antimicrobial activity of symbiotic bacteria and also bryozoans´ extracts were demonstrated in the marine bryozoans. Because of this, deeper knowledge of these largely unknown animals has become of high importance. Bacteria isolated from Pectinatella magnifica colonies collected in 2012 and 2013 in South Bohemia were tested for their antimicrobial aktivity against many strains of bacteria. Diffusion method was chosen for testing of the antimicrobial activity. Instead of application by paper disks, method using holes into solid agar was used. Into these holes, precisely selected volume of the supernatant of bacterial isolates has been dosed. In total, 170 supernatants were tested against 80 strains of bacteria. In the case of supernatant containing antimicrobial substances produced by the tested bacteria, an inhibition zone around the hole would be created. The antimicrobial activity has been confirmed in three cases while testing supernatant of symbiotic bacteria Aeromonas veronii and Pseudomonas moraviensis against strains of clostridia. Furthermore, it has also been confirmed, that Aeromonas veronii inhibited the growth of Pseudomonas moraviensis. In the remaining studied isolates, antimicrobial activity suppressing the growth of test bacteria has not been confirmed.
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Molecular phylogeny and genome evolution of insect symbiotic bacteria
NOVÁKOVÁ, Eva
Since the introduction of advanced molecular methods the research on insect bacterial symbioses underwent a major focus shift towards large scale phylogenetics and comparative genomics. These new fields provided answers to several fundamental questions of symbiont evolution, functional capabilities of the host-associated bacteria, and the role of symbionts in the host?s biology. However, the vast diversity and complexity of symbiotic relationships still leaves gaps in our understanding to a rich mosaic of various symbiont types, effects and transitions from facultative association to obligate mutualism. The presented study focuses on distribution, diversity, phylogenetic patterns, evolutionary transitions and genome evolution of two less known but ecologically diverse bacterial genera, Arsenophonus and Sodalis. The thesis also takes advantage of the knowledge on a well established symbiotic model between aphids and Buchnera and reveals several evolutionary patterns in the host and symbiont.
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