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Regenerace smyslových orgánů u raků
KOR, Golara
The antennae are a crucial sensory organ in crayfish that plays vital roles in their survival, communication, and orientation within their environment. They are equipped with sensory hairs that enable crayfish to detect various stimuli. Crayfish possess the unique ability to regenerate their antennae. Hemocytes are specialized cells within crayfish and play a crucial role in their immune system and contribute to the process of regeneration. We applied cryo-scanning and Transmission electron microscopies to study sensory organ morphology and regeneration in crayfish. In Chapter 2, cryo-scanning electron microscopy was used to identify potential differences in antennal morphology in six different crayfish species including marbled crayfish Procambarus virginalis, Mexican dwarf crayfish Cambarellus patzcuarensis, red swamp crayfish Procambarus clarkii, signal crayfish Pacifastacus leniusculus, common yabby Cherax destructor, and spiny-cheek crayfish Faxonius limosus. We observed significant differences among the six crayfish species in the ratios of antenna length, segment length and width to carapace length, and the number of segments. Examination of ultrastructural features unveiled differences in the distribution patterns of sensory hairs along the antenna and the morphology of the antennal surface. The varying morphology of antennae among studied species possibly indicates an adaptation to the specific conditions of their respective habitats. Furthermore, the outcomes demonstrated that a combination of variations in both antennal morphological characteristics and biometric measurements could effectively help us to distinguish the different studied crayfish species. In Chapter 3, the ultrastructural behaviour of hemocytes during coagulation and phagocytosis in the initial phases of injury in marbled crayfish was explored using transmission electron microscopy. During the coagulation process, hemocytes experienced marked transformations in morphology. The cytoplasmic granules exhibited a change from electron-dense to electron-lucent forms with the progress of coagulation. The transformed granules containing amorphous, electron-lucent material were observed to combine and release their contents into the extracellular space as part of the coagulation process. Additionally, it was observed that the nucleus contents also play a role in the coagulation process. Furthermore, the amputation of the leg led to substantial muscle degeneration, and phagocytic hemocytes start to take up the necrotic tissues. Besides, we observed the digested remains from phagocytized necrotic tissues merged into granules and other cellular components, thereby enhancing the granularity of the hemocytes and altering their cellular morphology. However, it is essential to note that hemocyte degranulation during coagulation could potentially reduce their granularity. Since morphological features are critical for classifying hemocytes, these morphological changes during coagulation and phagocytosis must be considered significant factors. The degenerated material that stored inside phagocytic hemocytes may have application in immunological and regeneration processes. In Chapter 4, we employed transmission electron microscopy to explore the ultrastructural aspects of potential immune cell involvement in nerve regeneration within crayfish antennae post-amputation. The findings indicated that, during nerve regeneration, all three forms of hemocytes were present. However, the granules within semi-granulocytes and granulocytes mainly contributed to the generation of new organelles such as mitochondria, the Golgi apparatus, and nerve fibers in the regenerated nerves of crayfish antennae. We revealed the transformation of granules of hemocytes into diverse organelles during the process of nerve regeneration at the ultrastructural level. In conclusion, these granules function as compact repositories of adaptable materials carried by immune cells, capable of transformatio
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Influence of bird schistosome Trichobilharzia regenti on haemocyte activity of lymnaeid snails
Skála, Vladimír
Gastropod molluscs are naturally exposed to various pathogens such as bacteria, or multicellular parasites that include digenetic trematodes (digeneans) which develop in snails. To combat these pathogens gastropods have evolved a sophisticated internal defence system that is composed of humoral and cellular arms. Lectins are probably the most important humoral components, whereas haemocytes represent the main effector cells. Immunity is one of the important factors determining compatibility/non-compatibility of gastropods and pathogens (particularly snails and trematodes). The introductory part of this thesis includes a review of literature focused on the components of the gastropod immune system and their reactions against pathogens represented by bacteria and digeneans. Additionally, selected immunomodulations caused by compatible digenean species are reviewed. Experimental work (presented in publications) focused mainly on the influence of the bird schistosome Trichobilharzia regenti on haemocyte activities of two lymnaeid snail species, Radix lagotis and Lymnaea stagnalis that are susceptible or refractory to the parasite, respectively. This schistosome parasite causes neuromotor disorders in specific definitive hosts (waterfowl), but it also causes cercarial dermatitis in accidental hosts...
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Influence of bird schistosome Trichobilharzia regenti on haemocyte activity of lymnaeid snails
Skála, Vladimír
Gastropod molluscs are naturally exposed to various pathogens such as bacteria, or multicellular parasites that include digenetic trematodes (digeneans) which develop in snails. To combat these pathogens gastropods have evolved a sophisticated internal defence system that is composed of humoral and cellular arms. Lectins are probably the most important humoral components, whereas haemocytes represent the main effector cells. Immunity is one of the important factors determining compatibility/non-compatibility of gastropods and pathogens (particularly snails and trematodes). The introductory part of this thesis includes a review of literature focused on the components of the gastropod immune system and their reactions against pathogens represented by bacteria and digeneans. Additionally, selected immunomodulations caused by compatible digenean species are reviewed. Experimental work (presented in publications) focused mainly on the influence of the bird schistosome Trichobilharzia regenti on haemocyte activities of two lymnaeid snail species, Radix lagotis and Lymnaea stagnalis that are susceptible or refractory to the parasite, respectively. This schistosome parasite causes neuromotor disorders in specific definitive hosts (waterfowl), but it also causes cercarial dermatitis in accidental hosts...
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Lymnaeid snails: hemocyte activities and their changes caused by Trichobilharzia infections
Jindrová, Zuzana ; Horák, Petr (advisor) ; Bilej, Martin (referee)
Molluscs as well as all other invertebrates rely on innate immune response only. Their internal defense system is capable of destroying most pathogens. However, there are some exceptions, e.g. some snails serve as intermediate hosts for some trematodes. Trematodes are able to develop inside these snails due to intervention in the snail internal defense system. The submitted thesis describes hemocyte activities of two lymnaeid snails, Lymnaea stagnalis a Radix lagotis, and the influence of Trichobilharzia regenti infection on R. lagotis hemocytes. Hemocytes of both species exposed to various chemicals produced different amounts of H2O2 and NO. The response varied between both lymnaeid species. The amount of circulating hemocytes was elevated in R. lagotis snails due to T. regenti infection. However, the infenction attenuated hemocyte activities monitored by us. Hemocyte basal NO production was decreased as well as phagocytosis of bacteria, cell adherence and pseudopodia formation. Toxicity of L. stagnalis plasma against T. regenti miracidia was also described. Mechanisms used by trematodes to interact with the snail internal defense system will help us to understand why one species is suitable for the develepment of the trematode whereas another closely related species kills it. Powered by TCPDF (www.tcpdf.org)
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