|
|
Diversity and phylogeny of Archamoebae
Zadrobílková, Eliška ; Čepička, Ivan (advisor) ; Kostka, Martin (referee) ; Valigurová, Andrea (referee)
Members of the group Archamoebae are free-living or endobiotic amoeboid flagellates and amoebae. They live in anoxic or microoxic habitats, and their mitochondria have been reduced. They were originally thought to lack mitochondria and represent one of the earliest eukaryotes. However, this hypothesis has been refuted, and now it is evident that the Archamoebae belongs to the lineage Conosa within the supergroup Amoebozoa, together with aerobic slime molds (Macromycetozoa) and variosean amoebae and flagellates. Relatively simple microtubular cytoskeleton is a characteristic feature of Archamoebae. It consists of a single basal body from which a flagellum arises, lateral root, and microtubular cone. Cytoskeleton of aflagellated genera has been completely reduced. About 350 species names of Archamoebae have been created so far. However, most descriptions were based on inadequate morphological features. The identity of numerous species is uncertain, and many of them are likely synonymous. Another problem is a small amount of available molecular data. During our project, we have substantially improved the dataset of DNA sequences of archamoebae. On the basis of molecular and morphological data, we described 13 new species. We showed that genus Rhizomastix belongs to Archamoebae and displays a new type...
|
|
|
Diversity of the genus Monocercomonoides
Vlasáková, Jitka ; Hampl, Vladimír (advisor) ; Kostka, Martin (referee)
Oxymonads (Excavata, Preaxostyla) are a group of anaerobic endobiotic flagellates living primarily in guts of xylophagous insects (cockroaches and termites). Some representatives of the genus Monocercomonoides belonging to the morphologically simplest family Polymastigidae have been described also from the guts of vertebrates. Oxymonads are a group of protist in which mitochondrion has not been proven yet. In this work, we have sequenced gene fo SSU rRNA of two strains of Monocercomonoides and performed phylogenetic analysis of oxymonads. Five selected strains Monocercomonoides isolated from different hosts and distantly related on the phylogenetic tree were studied by using light (DIC and protargol staining) and transmission electron microscopy. The aim was to find differences between these strains. We have focused primarily on the morphology of the nucleus, appearance of the endoplasmic reticulum and structure of the fibre R1. We were able to distinguish the strains by the position of karyosome (central and parietal) and the number of microtubules in the R1 fibre (6-12) and we assume that they represent separate species. The phylogenetic position and appearance of the strains NAU3 were so different that it may represent a new genus. Mitochondria or double-membrane bounded organelles have not been...
|
|
|
Development of surface and body musculature of the bird schistosome Trichobilharzia regenti
Bulantová, Jana ; Horák, Petr (advisor) ; Nebesářová, Jana (referee) ; Toledo, Rafael (referee)
Description of Trichobilharzia regenti as a new species of nasal bird schistosome in 1998 was only the first step in our knowledge of this extraordinary parasite. Natural definitive hosts of T. regeni are anseriform birds, but infective larvae - cercariae - are able to penetrate also into mammalian hosts including humans. There they are causative agents of hypersensitive skin immune reaction called cercarial dermatitis or swimmer's itch. Contrary to other schistosomes, miracidia of T. regenti hatch directly inside the definitive host tissue. Schistosomula migrate through the nervous system of vertebrates and, together with adult worms, they have predominantly extravascular localization in definitive hosts. Adult worms have a short lifespan and low degree of sexual dimorphism, connected with lower dependence of adult females on long-term contact with males. During the life cycle, T. regenti can be found within three different environments (freshwater, tissue of intermediate molluscan host and tissue of vertebrate host). Each of the seven developmental stages has a different role in the life cycle which corresponds with different organization of various organ systems. The introductory part of the thesis is focused entirely on ontogenetic changes of surface ultrastructure and body musculature of...
|
|
|
Development of surface and body musculature of the bird schistosome Trichobilharzia regenti
Bulantová, Jana
Description of Trichobilharzia regenti as a new species of nasal bird schistosome in 1998 was only the first step in our knowledge of this extraordinary parasite. Natural definitive hosts of T. regeni are anseriform birds, but infective larvae - cercariae - are able to penetrate also into mammalian hosts including humans. There they are causative agents of hypersensitive skin immune reaction called cercarial dermatitis or swimmer's itch. Contrary to other schistosomes, miracidia of T. regenti hatch directly inside the definitive host tissue. Schistosomula migrate through the nervous system of vertebrates and, together with adult worms, they have predominantly extravascular localization in definitive hosts. Adult worms have a short lifespan and low degree of sexual dimorphism, connected with lower dependence of adult females on long-term contact with males. During the life cycle, T. regenti can be found within three different environments (freshwater, tissue of intermediate molluscan host and tissue of vertebrate host). Each of the seven developmental stages has a different role in the life cycle which corresponds with different organization of various organ systems. The introductory part of the thesis is focused entirely on ontogenetic changes of surface ultrastructure and body musculature of...
|
|
|
Ultrastructure of eustigmatophycean algae
Fišerová, Melánie ; Němcová, Yvonne (advisor) ; Hyliš, Miroslav (referee)
In 1971, the algal class Eustigmatophyceae, Stramenopiles, was detached by Hibberd and Leedale from the class Xanthophyceae, Stramenopiles, on the basis of prominent ultrastructural differences in vegetative cells and more importantly in zoospores, such as the presence of big extraplastidial stigma. The class was divided into four families, six genera and twelve species. It seems so far, that there is a deep dichotomy within the class. Eliáš et al. (unpublished) recom- mend to establish two orders based on molecular sequencing of 18S rDNA and rbcL: Eustigmatales (sen- su Eustigmatophyceae described by Hibberd) and Goniochloridales (order containing Goniochloris, Pseu- dostaurastrum and undescribed relatives). The order Eustigmatales is divided into three separate lineages, most likely families: Eustigmataceae (A1), Monodopsidaceae (A2) and a new family Pseudellipsoidiona- ceae (A3). In this study the ultrastructure of 10 eustigmatophycean strains from three separate lineages was investigated. The typical characteristics of this class as chloroplast without a girdle lamella, a reddish glo- bule and lamellate vesicles were found in all strains studied. The appearance of the lamellate vesicles was found to change during the life cycle. My research indicates that other characteristics, formerly...
|
|
|
Evolution of mastigont in Excavata
Táborský, Petr ; Čepička, Ivan (advisor) ; Hampl, Vladimír (referee)
In recent years we have been discovering a huge diversity of eukaryotic organisms. One of the big super-groups is Excavata. Examination of the organisms from this group is fairly important as far as theoretical and practical reasons are concerned. A significant number of authors believe that there is the root of all eukaryotic organisms in this group. And what is more, a lot of studies prove the point. Within Excavata group we can find the organisms with the most primitive mitochondrial genome which is known. Several other representatives are an important human pathogenes. In the first part of the thesis I focus on the historical review of the creation of the super-group Excavata and I also include a part regarding the theory about Archezoa. The next section deals with the general description of mastigont (basal bodies and cytoskeleton that is associated with them). The last part presents mastigont descriptions of some derived representatives of Excavata. Some of these organisms may be free-living and some live inside other organisms.
|
|
|
Study of the reproductive biology of the crayfish - mating, laying eggs and morphological structure of the male and female gametes
KUBEC, Jan
In the nature, crayfish are represented like predators or a part of food base of some fish. Also in free waters they acts as detrivors and are an important element in the nutrient and energy circle in aquatic ecosystem. The crayfish weren't able to avoid negative impacts of anthropogenic activities such as water pollution and devastation of habitats. For these reasons reproduction of the crayfish is necessary in hatcheries and farms. The main aim of my work was to study the reproductive biology of the crayfish focused on the process of mating, the interval between mating and laying eggs, fertilization and morphological structure of the male and female gametes. Among the secondary objectives there was included using of repeated electrostimulation of the crayfish and the possibility of hybrids of the noble crayfish (Astacus astacus) and the narrow-clawed crayfish (Astacus leptodactylus). The observation of the period of reproduction was realized on representativies of the noble crayfish and the narrow-clawed crayfish throughout natural mating in the tanks. The structure of gametes was observed on the samples taken from thenoble crayfish (Astacus astacus), the narrow-clawed crayfish (Astacus leptodactylus), the signal crayfish (Pacifastacus leniusculus), the red swamp crayfish (Procambarus clarkii) and spinycheek crayfish (Orconectes limosus). The experiments were carried out during the autumn season in 2012 and 2013. The results of observations of the reproduction of crayfish made us clear as for the period and intervals for all phases of the process of mating crayfish. For females the noble crayfish and the narrow-clawed crayfish was found oviposition without the presence of males. Their individual components have been described by using ultrastructure of males and female gametes. Repeated electrostimulation showed at the family Astacidae as a suitable tool for collecting large mass of sperm material. Hybridization experiment proved that it can occur to mate the two species of crayfish in areas where they occur simultaneously. These experiments helped to further knowledge of reproductive biology of crayfish.
|
|
| |
guest ::
