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Obranné reakce včel vůči přírodním toxinům
KAINZOVÁ, Klára
The aim of this master thesis was to describe the effect of honeybee venom on several physiological characteristics in the honeybees Apis mellifera themselves. They included the expression and level of vitellogenin in selected organs, AKHs production in CNS, level of dopamine in brain, fat body and Malpighian tubules, oxidative stress (the activity of catalase) and the structure of thoracic muscles in workers and drones. Results showed that the bee venom did not change the AKH level in CNS. However, the envenomation decreased the expression of vitellogenin in fat body, as well as the level of vitellogenin proteins both in fat body and haemolymph. Catalase activity was increased in the gut of workers but decreased in the gut of drones. The venoms application slightly increased dopamine levels in the fat body, brain and Malpighian tubules, but only in the fat body the rise was significant. Honeybee venom damaged the structures of myofibrils and mitochondria in the thoracic muscles of workers, however, co-application of the venom with AKH generally abolished this effect; situation in drones remains unknown.
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Vliv přírodních toxinů na včelu medonosnou
KAINZOVÁ, Klára
The aim of this bachelor thesis was to describe the effect of honeybee venom on the activity of digestive enzymes (amylases, proteases, lipases), AKHs production in CNS, and level of nutrients (lipids, proteins, glycides) and vitellogenin in haemolymph of the honeybee Apis mellifera workers. Crude venom was applied into the honeybee body 24 hours before determination of the above mentioned characteristics. Results showed that the bee venom reduced the AKH level in CNS, increased activity of digestive enzymes in gut, and increased level of vitellogenin in haemolymph. Effect of the venom on nutrient level in haemolymph was variable - level of lipids and carbohydrates was enhanced, while level of proteins reduced.
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Study of adipokinetic hormone role in insects stressed by entomopathogenic nematodes
IBRAHIM, Emad Ahmed Sayed
In this thesis, the effect of infection elicited by entomopathogenic nematodes (EPNs) Steinernema carpocapsae on Pyrrhocoris apterus and Drosophila melanogaster models were evaluated, and a role of adipokinetic hormones (AKHs) during the infection was characterized. These were monitored by determination of mortality, and various biochemical and physiological characteristics such as AKH levels both in the central nervous system (CNS) and in hemolymph, AKH gene expression in CNS, level of anti-oxidative stress markers, general metabolism and level of nutrients in normal and genetically modified insects. At P. apterus the mortality tests revealed that application of AKH increases the efficacy of EPN treatment. This result was confirmed using the firebugs with AKH receptor deficiency. Further, the increase of AKH expression and AKH levels in CNS and hemolymph seemed to be coordinated after the nematode treatment. At the D. melanogaster model also, the effect of adenosine into the above-mentioned characteristics was included. For this, mutants in AKH (AHK1), adenosine receptor (AdoR1) genes, and in both these genes together (AHK1 AdoR1 double mutant) were employed. Altogether, the results confirmed the involvement of AKH, and partially also adenosine into the antistress defense reactions elicited by the nematobacterial infection. Finally, the last part of the study was focused on examination of the vitellogenin (Vg) role in the defense reaction in firebug body P. apterus affected by two entomopathogenic organisms, the nematode S. carpocapsae and the fungus Isaria fumosorosea. The results revealed that Vg proteins play an important role in the defense against both types of the infections and are also able to kill entomopathogenic bacteria Xenorhabdus nematophila, that are symbionts of S. carpocapsae and that increase toxicity of this nematode.
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Are silkworm males capable of producing vitellogenin?
VRCHOTOVÁ, Markéta
The eggs of the silkworm, Bombyx mori, obtained from the ovaries implanted into male hosts are able to complete embryonic and post-embryonic development in spite of the very low amount of vitellogenin. Using polyacrylamide gel electrophoresis, I searched for differences between the protein spectra of eggs from standard females and the eggs from ovaries implanted into the males. I also examined the variability of protein spectra in the eggs of several parthenoclones. I confirmed great differences in the egg protein spectra between the eggs from females and those from the ovaries implanted into males. Both heavy (180 kDa) and light (42 kDa) subunits of vitellogenin were present in the eggs from females but only the heavy subunit of vitellogenin was found in the eggs developed in ovaries implanted into male hosts. Interesting interactions between transplanted gonads and the host milieu were observed. All compared parthenoclones contained similar patterns of the main yolk proteins but differed slightly in some high-molecular weight protein fractions.
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IMPACT OF MUNICIPAL POLLUTION ON FISH LIVING IN A SMALL STREAM
HORA, Vojtěch
Main objective of this thesis is evaluation of the impact of extraneous substances that enter Živný stream through the WWTP Prachatice onto the stream's fish population. Brown trout (Salmo trutta m. fario) was selected as a sampling organism. Sampling was conducted in 2012 using an electrical aggregate at three locations. The sample counted a total of 36 fish. Subsequently there was conducted blood sample and tissue analysis using selected biomarkers (vitellogenin and EROD). Furthermore, an analysis of fish tissue and water samples was made to identify presence of selected extraneous substances.Concentration of vitellogenin in blood plasma of male fish in the controled location was zero, in polluted location the average concentration varied between 275 and 573 ng.ml-1. Concentration of vitellogenin in blood plasma of female fish was the lowest at a location directly downstream the WWTP (7 185 823 ng.ml-1). At other locations, the average concentration ranged between 9 250 302 - 11 614 177 ng.ml-1. The activity of liver detoxifying enzymes (EROD) was the highest at polluted locations, between 63,9 - 87,4 pmol.mg-1protein.min-1. In the controled location was the lowest activity EROD (5,4 pmol.mg-1protein.min-1). The result of identification of selected extraneous substances in fish tissues (liver) and in the water is a sum of all detected pharmaceuticals. In fish tissues was the sum of all detected pharmaceuticals in the range from 20,8 to 138,8 ng.g-1, while in water it varied between 0,07 - 3,00 ?g.l-1. The highest values were again measured in polluted areas. The results of the analyses conducted imply, that the present concentrations of extraneous substances in Živný stream downstream from Prachatice have a negative impact onto live organisms.
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Vliv endokrinních disruptorů na funkčnost spermií a změny ve steroidogenezi transkriptomik u ryb
HATEF, Azadeh
In the present study, both in vitro and in vivo experiments were performed to investigate modes of action of selected EDCs including mercury chloride (HgCl2), bisphenol A (BPA), vinclozolin (VZ) and Di-(2-ethylhexyl)-phthalate (DEHP) on male reproductive physiology in fish. Results obtained from in vitro studies showed that EDCs decrease sperm motility via disruption in energetics and damage to spermatozoa; however the effective doses are higher than reported in the environmentally relevant concentrations. In contrast, in vivo studies showed adverse effects of BPA, VZ, and DEHP on sperm quality at environmentally relevant concentrations. Decrease in sperm quality is associated with disruption in testicular steroidogenesis, particularly inhibition of androgens. Only BPA induced vitellogenin production, associated with increase in transcripts of estrogen receptor, androgen receptor and cytochrome P450 mRNA at the high dose approaching environmental level. Inhibition of androgen production is due to disruption in transfer of cholesterol into the steroidogenesis pathway, because transcript of steroidogenic acute regulatory protein mRNA was decreased. In addition, BPA acts through sex steroid-mediated mechanism while DEHP mode of action is sex-steroid independent mechanism.
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