National Repository of Grey Literature 7 records found  Search took 0.02 seconds. 
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.
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.
Vliv paralytického jedu lumčíka, \kur{Habrobracon hebetor}, na svalovou tkáň zavíječe, \kur{Ephestia kuehniella} a octomilky, \kur{Drosophila melanogaster}
PODLAHOVÁ, Šárka
The ectoparasitoid wasp Habrobracon hebetor uses its effective venom for inducing neuromuscular paralysis to ensure the proper development of its progeny in the host attacked. However, the associated mechanism of the paralysis is not known yet. The action of the venom was studied in the muscle tissue of its host larvae Ephestia kuehniella and in the model organism Drosophila melanogaster using transmission electron microscopy (TEM). Preparation of the samples for TEM was optimized to protect tissue integrity and to minimalize artefacts. The results revealed that the wasp venom affected neither the organization of muscle fibres nor the structure of mitochondria. Furthermore, potential D. melanogaster mutants of glutamate receptor subunits GluRIIA and GluRIIB were analyzed, and the role of glutamate receptors in regulation of paralysis was discussed.
Evolution of sting and associated venom gland in Hymenoptera (Aculeata)
Matějková, Zuzana ; Straka, Jakub (advisor) ; Šobotník, Jan (referee)
Theme: Evolution of the sting and associated glands in Hymenoptera (Aculeata) Author: Zuzana Matějková Supervisor: Mgr. Jakub Straka, Ph.D. Abstract A stinger is a synapomorphy of Aculeata group. The branch of Aculeata has cleaved from the Parasitica group - they both belong to the order Apocrita. The stinger of Aculeata has evolved from a former ovipositor - though the function of laying eggs has been lost. Besides venom gland several other glands including Dufour's gland vent into a stinger. The original (parasitic-predator strategy- binding) function of the gland excretes is a paralysis of the prey. In social Aculeata it gains a defensive function - associated with a possible act of autotomy of the stinger. The stinger and associated glands are also a source of pheromones and small peptides with an antimicrobial function. These peptides act together with other venom components and they help to improve its effectiveness.
Antimicrobial peptides isolated from the venom of hymenopterous insect
Monincová, Lenka ; Čeřovský, Václav (advisor) ; Macek, Tomáš (referee) ; Fusek, Martin (referee)
Rapid development of bacterial resistance and multiresitance to conventional antibiotics has resulted in an intensive search for alternative antimicrobial agents. Antimicrobial peptides (AMPs) belong to promising anti-infective candidates since they do not development bacterial resistance. They kill microbes by disturbing or permeabilizing the cytoplasmic membrane, or may target putative key intracellular compartments. Their advantages include fast action and selectivity between prokaryotic and eukaryotic cells. We have isolated several novel AMPs from the venom of wild bees: halictines (HAL-1 and HAL-2) from Halictus sexcinctus, lasiocepsin (Las) from Lasioglossum laticeps and macropin (MAC-1) from Macropis fulvipes. They are active against Gram-positive and Gram- negative bacteria and against yeast Candida albicans. While halictines and macropin have moderate hemolytic activity, Las shows no hemolytic activity. A novel AMP was isolated also from the mucus of Xiphydria camelus. This AMP belongs to the category of insect defensins. It contains 55 amino acid residues, three disulphide bridges and its C-terminus is amidated. CD and NMR studies of HAL-1, HAL-2 and MAC-1 revealed propensity to form amphipathic α-helical structure in the presence of sodium dodecyl sulfate or trifluoroethanol. For the...

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