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Selected aspects of biology of the invasive species \kur{Pectinatella magnifica}
JEŽKOVÁ, Eva
Pectinatella magnifica, invazní organismus, statoblast, rozmnožování, laboratorní kultivace SUMMARY Pectinatella magnifica is an invasive organism transfered to Czech republic from the USA with the international boat transport. Here it poses a lot of potencial threats toour native species, as well as to submerged technical constructions. It is a species of freshwater Bryozoan that is able to create colonies of considerable sizes. On the surface of a gelatinuous matrix there are small living indiviuals called the zooids. These can reproduce both sexually and asexually, which gives them a huge competitive potential. The dormant asexual spores, e.g. statoblasts, are extremely resistant towards various natural conditions and have characteristics enabling them to spread to substantial distances. This thesis aimed to identify and describe several life aspects of Pectinatella magnifica, especially reproduction and spreading strategy. I monitored the organism in the nature, as well as in a number of laboratory experiments. I was able to succesfully transfer the colonies of Pectinatella from the ponds into a special aquarium system. Under the laboratory conditions, 80 % of statoblasts germinated within five to eight days, depending on the water temperature. Then the zooids emerged and survived for around eight weeks, enabling me to observe different development and behaviour. Obtained photo and viceodocumentation shows details of a sexual reproduction of zooids, proving that it occurs even in our environment. The most prefered natural conditions seem to be the flooded mezotrophic sand quarries and protected and recreational ponds with a low fishing stock (without a massive algeae presence, fluctuating oxygen levels, etc.) The results do not suggest that Pectinatella magnifica is currently a significant competitor to our native Bryozoan species.
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Study of genetic diversity of Pectinatella magnifica (Leidy, 1851) colonies
MORAVCOVÁ, Vendula
Pectinatella magnifica is a freshwater organism from the bryozoan group, living in oligotrophic and mesotrophic waters where the temperature reaches 20°C during the year. It was first found and described by Joseph Leidy in the Philadelphia area in 1851. Although the original place of occurrence is North America, it is currently known as an invasive organism on other continents as well. Representatives of the species Pectinatella magnifica live in colonies with a characteristic spherical shape, which makes it easy to recognize and identify. These spherical colonies are covered with a community of zooids that produce a gel-like substance filling the colony itself. The reproduction of bryozoans is both sexual and asexual, with the non-sexual part exceeding the sexual part. The product of asexual reproduction are internal buds, so-called statoblasts, equipped with hooks, thanks to which they can attach to any substrate, which enables easy distribution even over long distances through otherwise difficult terrain. Although this is an ancient group with a predominance of asexual, therefore clonal, reproduction, the sexual part of reproduction enables the emergence of mutations and adaptation to new conditions. The dissertation is focused on determining the genetic diversity of colonies taken from the territory southern Bohemia and the surrounding area using molecular marker techniques. Two molecular techniques were used for processing genetic analyses, namely AFLP (Amplified Fragment Length Polymorphism) and ISSR (Inter Simple Sequence Repeat). Both techniques use universal primers to determine similarity between organisms.
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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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Study of genetic diversity of colonies Pectinatella magnifica
MORAVCOVÁ, Vendula
Pectinatella magnifica is a colony of freshwater organisms, which are most often found on the submerged parts/branches of coastal plants, but also fixed to stones, growing at the bottom of ponds, or free - floating. These organisms can be found mostly in oligotrophic to mesotrophic waters, and appear to thrive in temperatures that reach 20°C during colonisation. They were first found and described in Philadelphia in 1851, by Joseph Leidy. Although Pectinatella magnifica originates from North America, it has now become an invasive species on the other continents. The first recorded occurrence in Europe was during the 1980s in Hamburg, where it was probably transported on ships' hulls. In the Czech Republic it was recorded for the first time in rivers Vltava and Labe in the first half of the 20 th century. The most common method of its propagation is through internal buds, called statoblasts, fitted with hooks that make it able to cling to any surface, and allow easy distribution over long distances and otherwise impossible terrain. This study uses AFLP analysis of statoblast DNA to analyse the genetic diversity within P. magnifica colonies themselves, changes over time, and between different sites within the Protected Landscape Area (PLA) and a Biosphere Reserve (BR) of Třeboňsko, namely ponds Veseli I, Staňkovský, Nový Kanclíř, Cep, Vlkov and Nový Lipnický.
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Response of animal cells to the extract, obtained from the colony matrix of Pectinatella magnifica
ŠUSTEROVÁ, Karolína
The aim of this thesis was to determine whether colonies freshwater bryozoans Pectinatella magnifica produce biologically active substances. On the basis of knowledge of the course of the growth curves of cell culture mouse fibroblasts were developed models for biological assays to determine the biological potential of substances contained in the extract of lyophilisate colonies of P. magnifica. Tests demonstrated the presence of substances with biological activity. Next part of this work was also survey the occurrence and distribution of the reference type to Vltavotýnsku, including the monitoring of basic parameters of the aquatic environment. It was explored in two years (2012 and 2013) repeated a total of 10 sites on rivers Vltava and Lužnice, the incidence was detected at 5 locations .
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Spreading of Bryozoa Pectinatella magnifica in Třeboňsko region
LUKEŠOVÁ, Petra
Pectinatella magnifica is a fresh water invertebrate colonial animal originating from North America which spreading, throughout Europe as well as Asia, has recently reached a characteristics of invasion. Charakter of the colonies, their seasonnal dynamics and other development aspects have been studied at six destinations in South Bohemia (lake Cep, Nový Lipnický pond, Hejtman pond, Nový Kanclíř pond, Vlkov sandpit and Hnevkovice water reservoir). Repeated biomass quantitative collections have been carried out in 10 m transects alongside the shoreline. Also the environmental factors have been found out (temperature, conductivity, water reactions, transparency, trophia, colonies substrate) and charakteristics of individual invaded reservoirs. The list of currently known destinations has been completed with another reservoirs into which the species has spread out.
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