(magistrsko delo)
Nina Brdelak (Author), Saška Lipovšek Delakorda (Mentor), Tone Novak (Co-mentor)

Abstract

Raziskovali smo strukturne in ultrastrukturne spremembe celic srednjega črevesa pajka Meta menardi v nadzorovanih razmerah stradanja pozimi, torej v izzvanem prezimovanju, kar je primerljivo naravnem stradanju pozimi, če pajek ne ulovi nobenega plena. Metodologija raziskovanja. Ob pisanju teoretičnega dela magistrske naloge smo si pomagali z ustreznimi članki različnih avtorjev in internetnimi viri. Podatke empiričnega dela za izvedbo magistrske naloge smo pridobili z delom v laboratoriju. Rezultati. Ugotovili smo, da so v epitelu srednjega črevesa prisotne sekrecijske in prebavne celice ter adipociti. Apikalni del epitelnih celic z mikrovili meji na črevesni lumen. Sekrecijske celice vsebujejo številne cimogene granule, prebavne celice pa številne prebavne vakuole. Na začetku prezimovanja so prebavne vakuole pri obeh spolih vsebovale večje količine elektronsko gostega materiala kot ob koncu prezimovanja. Adipociti so pri obeh spolih vsebovali veliko lipidnih kapelj in zrn glikogena. V sredini prezimovanja so prebavne vakuole pri samcih vsebovale več elektronsko gostega materiala kot pri samicah, kjer je bilo elektronsko gostega materiala zelo malo (večji del je predstavljal elektronsko svetel material). V adipocitih smo pri obeh spolih opazili porabo glikogena ter lipidov. Pri samcih v prebavnih vakuolah v prebavni celici ob koncu prezimovanja ni bilo elektronsko gostega materiala, v nasprotju s samicami, kjer so še bile prisotne manjše količine elektronsko gostega materiala. Ob koncu prezimovanja so adipociti pri samcih vsebovali več lipidnih kapelj kot adipociti samic; pri samicah so bile posamezne lipidne kaplje v osrednjem delu celic. Ob koncu prezimovanja so bili v sekrecijskih celicah samcev prisotni posamezni avtofagosomi, v prebavni celici pa smo našli avtolizosom. Med prezimovanjem so bili v epitelnih celicah srednjega črevesa prisotni tudi številni sferiti. Njihova zgradba se je med prezimovanjem pri obeh spolih spreminjala. Posamezne plasti materiala so se postopoma porabljale in ob koncu prezimovanja so bili sferiti večinoma prazni. Sklep. Ultrastruktura celic srednjega črevesja se pri pajku Meta menardi pozimi med nadzorovanim stradanjem spreminja. Na začetku prezimovanja so prebavne vakuole v prebavnih celicah pri obeh spolih vsebovale več elektronsko gostega materiala kot ob koncu prezimovanja. Za sekrecijske celice so značilne številne cimogene granule in zrnati endoplazmatski retikulum. V adipocitih so poleg velikega števila zrn glikogena prisotne številne lipidne kaplje, ki so na začetku prezimovanja tesno ena ob drugi in pritiskajo ob jedro. Struktura sferitov se med prezimovanjem spreminja. Ob koncu prezimovanja so pri obeh spolih prisotne avtofagne strukture (avtofagosomi in avtolizosomi). Med spoloma obstajajo manjše razlike v ultrastrukturi celic srednjega črevesa in v uporabi založnih snovi.

Keywords

pajkovci;srednje črevo;prezimovanje;stradanje;ultrastruktura celic prebavila;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FZV - Faculty of Health Sciences
Publisher: [N. Brdelak]
UDC: 591.132.5:595.44(043.2)
COBISS: 2327972 Link will open in a new window
Views: 1128
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Other data

Secondary language: English
Secondary title: The structure of the midgut in a large cave spider, (meta menardi) (latreille 108) (araneae, tetreagnathidae) during overwintering in controlled conditions
Secondary abstract: The research topic of the master thesis were structural and ultrastructural changes in the midgut cells of the spider Meta menardi under controlled starvation conditions in winter. Such controlled conditions of starvation are comparable to the natural winter starvation, if a spider doesn't catch any prey. Research methodology. In theoretical part of the master thesis we refer to information in relevant articles produced by many authors, and relevant websites. Empirical data were acquired through research in the laboratory. Results. We found secretory cells, digestive cells and adipocytes in the mid-gut epithelium. The apical part of the epithelial cells faces the intestinal lumen. The secretory cells contain numerous zymogene granules, while the digestive cells contain numerous digestive vacuoles. In both sexes, at the beginning of the experiment, the digestive vacuoles were larger and contained larger amount of electron-dense materials, while this material was less abundant at the end. Glycogen consumption in adipocytes was observed in both sexes. Large amount of lipid droplets and glycogen granules were found in male digestive vacuoles in the middle of overwintering, in contrast to females, where there electron-lucent material prevailed. Glycogen consumption in adipocytes was observed in both sexes. At the end of overwintering there was no electron-dense material in the male midgut cells, while there was small amount of electron-dense material in females. Male adipocytes contained larger amount of lipid droplets than female adipocytes; in females, a number of individual lipid droplets was found in the central part of the cells. At the end of overwintering, in both sexes in the digestive cells there were autophagosomes in the secretory cells and autolysosomes. We also noticed a number of spherites in the epithelial cells. Their structure changed in both sexes during overwintering. The spherital layers were gradually decomposed, and at the end of overwintering spherites were mostly exploited. Conclusion. During overwintering under controlled conditions, changes in the ultrastructure of the midgut epithelial cells in the spider Meta menardi appear. There are numerous cytoplasmic digestive vacuoles in the digestive cells and numerous zymogene granules in the secretory cells at the beginning of overwintering. A more abundant rough endoplasmic reticulum is characteristic in males. In addition to a large number of glycogen granules in adipocytes, there is a number of lipid droplets close to the cell membrane. The ultrastructure of spherites changes during overwintering. At the end of overwintering, autophagic structures (autophagosomes and autolysosomes) are presented in both sexes. The ultrastructure of the midgut changes in both sexes during overwintering. There are small differences in the use of reserve substances between the sexes.
Secondary keywords: arachnids;midgut;overwintering;starvation;ultrastructure of the midgut cells;
URN: URN:SI:UM:
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za zdravstvene vede
Pages: IX, 47 f., 2 f. pril.
ID: 9600095