National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Influence of pesticides on bees with focus on their endocrine disruptive effect
Bártová, Kateřina ; Erban, Tomáš (advisor) ; Hrabák, Jaroslav (referee)
The aim of this bachelor thesis is to assess the effect of imidacloprid in interaction with the mite Varroa destructor and deformed wing virus (DWV), transmitted by this mite, on the honeybee. Imidacloprid is a systematic pesticide belonging to the group of neonicotinoids acting as an agonists of acetylcholine receptor. The use of neonicotinoids in EU has been banned in 2013 due to its impact on honeybee health. However, residues of these substances still occur in the environment. Since 1950s, the mite V. destructor has spread from the original host Asian honeybee (Apis cerana) to the European honeybee (Apis mellifera). Varroa is serving as the vector for viruses, like DWV causing the crippled wings. Residues of pesticides, varroosis, viral and bacterial diseases together with other factors can cause honeybee colony collapse. These factors can interact via hidden mechanisms of interactions and affect honeybee health. The model experiment was performed using emerging worker bees. A total of four trials were performed. Two variants were treated with imidacloprid or the bees were exposed to Varroa collected from colonies with DWV clinical signs. Bees were fed with sugar solution or sugar solution with 2.5 μg/l of imidacloprid. Experiment lasted 72 hours and samples were analysed using a...
Physiological changes during honeybee (Apis mellifera) ontogenesis and between castes
Martišková, Ester ; Erban, Tomáš (advisor) ; Čapková Frydrychová, Radmila (referee)
This work is focused on describing the individual differences in physiology of honeybee Apis mellifera during its development. It also compares the differences between the individual caste. A lot of complex rebuilding of the whole organism takes place during the development of Apis Mellifera. Because of that, especially in the early stages, it is important to ensure a great supply of energy. Larvae need to acquire an abundant source of nutrients, so they can grow fast and have a sufficient storage for the pupal stage, during which the new body reorganization takes place. Newly emerged bees then need to quickly get accustomed to the new environment a assume their role in the hive. Queens need a constant supply of energy, so they can lay eggs for as long as possible. Drones focuse mainly on mating with the queen. The life of Apis mellifera is also influenced by other factors, primarly by numerous diseases and pathogens. The results of this work can give a comprehensive idea about the complex development of an individual bee and give a of further research. There are still a lot a lot of unanswered and unexplored realities in biology of bees, that could a topic of study and help us better understand their importance for nature.
Influence of neonicotinoids on insect communities with focus on bees
Weingartová, Barbora ; Erban, Tomáš (advisor) ; Šípek, Petr (referee)
The bachelor thesis is focused on pesticides and their impact on the environment. Plant protection products must undergo a comprehensive assessment involving the impact on nontarget organisms. Negative effects of pesticides are not only assessed in humans and other vertebrates but also in invertebrates. Pollinators that play a vital role in ecosystems are an important group for evaluation. This thesis specializes in a group of pesticides called neonicotinoids, some of which are currently banned in some countries. This thesis mentions array of neonicotinoids, their toxicity and effects on pollinators that were observed. Reassessment is crucial in order to make a comprehensive picture of whether the ban was correct. . Keywords: pesticides, neonicotinoids, pollinators, honeybees, bumblebees, colony collapse disorder
A new approach for assessing the suspected pesticide poisonings of honeybees: certified methodology
Erban, Tomáš ; Kamler, Martin ; Kadlíková, Klára ; Markovič, Martin ; Titěra, Dalibor ; Seifrtová, Marcela ; Halešová, Taťána
Honeybee colonies are exposed to hundreds of plant protection products, which are especially due to improper use possible source of honeybee poisoning. The methodology introduces to the issue of honeybee poisoning including legislation and contributes with novel aspects to the indication and evaluation of the suspected honeybee poisonings, which are anually investigated by the State Veterinary Administration and the Central Institute for Supervising and Testing in Agriculture in Czechia. The methodology provides instructions to identify honeybee posining and notification of that finding. Moreover, possible confusions of the poisonings with honeybee diseases are highlighted. Some sections of the methodology provide innovative recommendations for improvement of honeybee poisoning assessing including determination of the extent of colony contamination. The present methodology is useful for the state administration, beekeepers, scientific and educational purposes.
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Nutritional biology of synanthropic mites (Acari: Acaridida)
Erban, Tomáš ; Smrž, Jaroslav (advisor) ; Grubhoffer, Libor (referee) ; Šustr, Vladimír (referee)
Ph.D. THESIS TITLE Nutritional Biology of Synanthropic Mites (Acari: Acaridida) ABSTRACT Several attempts to describe the nutritional biology of acaridid mites were undertaken, however full understanding of these processes remains incomplete. The objective of this Ph.D. thesis was to expand our knowledge concerning digestive physiology of stored product and house dust mites and to apply this knowledge to their nutritional biology. The research approach adopted in this Ph.D. thesis includes in vitro characterization of enzymatic activity in whole mite extracts (WME) and spent growth medium extracts (SGME), evaluation of the enzyme activities with respect to the gut physiological pH, enzyme inhibition experiments, in vivo localization of enzyme activities in the mite gut, determination of effects of nutrient or antifeedant additives in experimental diets on mite population growth and determination of the feeding preferences of synanthropic mites as assessed by in vitro and in vivo analyses. The gut contents of twelve species of synanthropic acaridid mites were determined to be within a pH range of 4 to 7 and showed a pH gradient from the anterior to the posterior midgut. The pH in digestive tract of synanthropic acaridid mites corresponds to the activity of proteases, α-glucosidases, α-amylases and...
Nutritional biology of synanthropic mites (Acari: Acaridida)
Erban, Tomáš
Ph.D. THESIS TITLE Nutritional Biology of Synanthropic Mites (Acari: Acaridida) ABSTRACT Several attempts to describe the nutritional biology of acaridid mites were undertaken, however full understanding of these processes remains incomplete. The objective of this Ph.D. thesis was to expand our knowledge concerning digestive physiology of stored product and house dust mites and to apply this knowledge to their nutritional biology. The research approach adopted in this Ph.D. thesis includes in vitro characterization of enzymatic activity in whole mite extracts (WME) and spent growth medium extracts (SGME), evaluation of the enzyme activities with respect to the gut physiological pH, enzyme inhibition experiments, in vivo localization of enzyme activities in the mite gut, determination of effects of nutrient or antifeedant additives in experimental diets on mite population growth and determination of the feeding preferences of synanthropic mites as assessed by in vitro and in vivo analyses. The gut contents of twelve species of synanthropic acaridid mites were determined to be within a pH range of 4 to 7 and showed a pH gradient from the anterior to the posterior midgut. The pH in digestive tract of synanthropic acaridid mites corresponds to the activity of proteases, α-glucosidases, α-amylases and...
Proteomic analysis of lysozyme and lysozyme-like proteins of synanthropic mites
Chum, Tomáš ; Erban, Tomáš (advisor) ; Mikeš, Libor (referee)
This diploma thesis was focused on the study of lysozyme and lysozyme-like proteins, either of similar function (antibacterial) or molecular weight (14 - 17 kDa), of synanthropic acaroid mites. In general, animals utilize lysozymes for defensive (antimicrobial) or digestive purposes but also as a digestive enzyme. Some chitinases or other enzymes that act similarly to lysozyme can be utilized for similar purposes. Chitinases belong to house dust mite allergens. One of major mite are historically named lysozyme-like proteins which name relates to their size similar to lysozyme. Bacteriolytic activity has also 14.5 kDa (UniprotKB Q8MWR6) protein. The species selected for the study were domestic mites Dermatophagoides farinae, D. pteronyssinus and Lepidoglyphus destructor. Presence of lysozyme was detected by direct detection with polyclonal antibody using immunohistochemistry and dot blots. Immunohistochemistry proved presence of lysozyme epitopes in the feces of D. farinae, D pteronyssinus a L. destructor. Dot blot analysis demonstrated the presence of imunoreactivity of antibody in spent growth medium extracts (SGME) of all three species. This implies that lysozyme is synthesized in the midgut. The presence of lysozyme and lysozyme-like proteins was proved using 2D electrophoresis and MALDI TOF/TOF...
Study of physiology and searching of proteomic tools useful in suppression and detection of Varroa destructor
Holenková, Martina ; Erban, Tomáš (advisor) ; Titěra, Dalibor (referee)
This work is focused on the study of physiology and proteome of the the mite Varroa destructor and on comparison with the honeybee Apis mellifera. Varroa is currently a major problem for beekeeping, because infects most of the colonies. The control of the mite can not be done without residues both in the hive and for example in the honey or other resources used by the man. Another problem can also be the simultaneously discussed issue of the connection with the Colony Collapse Disorder. The internal anatomy of V. destructor was studied by using paraffin histology. On histological sections stained using hematoxylin and PAS was possible to observe the mite digestive system, but also egg, ovaries or brain. The primary aim of this study was to identify the proteins of mite V. destructor and bee A. mellifera as a host of this parasite. For the electrophoretic separation was used two- dimensional gel electrophoresis, where the second dimension was carried out using 12% and 15% SDS-PAGE. The most abundant spots were selected for analysis using MALDI TOF/TOF mass spectrometry. The most abundant protein identified in samples of V. destructor was hexamerin, arginine kinase or hemelipoglycoprotein precursor. Hexamerins were also identified as the major proteins in the pupae samples. On the contrary the main...
Secondary metabolite production in actinomycetes izolated from potato rhizosphere.
Komžák, Ondřej ; Erban, Tomáš (referee) ; Bosáková, Zuzana (advisor)
This bachelor thesis is focused on searching for secondary metabolite producers suppressing Streptomyces scabies (synonym scabiei), which is a causative agent of common potato scab affecting some species of agricultural crops. By the 16S rRNA gene sequencing strains of bacteria from potato rhizosphere were identified and strains effectively suppressing Streptomyces scabies were determined by a simple cultivation test. The work on this project will continue by focusing on identification of those secondary metabolites by HPLC.

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