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Sex chromosomes of Nematocera
Ryšan, Tadeáš ; Volf, Petr (advisor) ; Šťáhlavský, František (referee)
The paraphyletic group Nematocera is highly diversified in both body morphology and life strategies. Based on sex chromosome morphology, it can be divided into four groups defined as early as the mid- 20th century. All these systems are based on the presence of the XY/XX sex chromosomes or the loss of the Y chromosome. The different groups are distinguished based on whether the chromosomes are differentiated, whether chiasmata are present and whether the Y chromosome is retained. However, later research has shown much higher sex chromosome diversity, mostly in groups with homomorphic gonosomes. Even though most representatives of this group do not have differentiated sex chromosomes, we find the recurrence of differentiated gonosomes and even the X1X2Y1Y2/ X1X1X2X2 and ZW/ZZ sex systems, which are less typical for Diptera. These findings suggest that the form of sex chromosomes in Diptera may not be as stable as previously thought. The recently discovered non- homology of gonosomes across the Diptera, including several representatives of Nematocera, supports this idea. Multiple independent gonosome formation could also explain the diversity of primary sex- determining factors in those groups where these factors are known. Key words: Nematocera, Phlebotomus, Lutzomyia, sex chromosomes, sex determination
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Parous and nulliparous female detection in blood-sucking nematocera insects
Mračková, Marie ; Votýpka, Jan (advisor) ; Král, David (referee)
Nematocerous insects belong to the order Diptera, one of the largest and worldwide spread groups of insects. Haematophagous species act not only as tormentors, but also as vectors of various pathogens. The first section of this thesis reviews about insetct's reproductive systems, multiple blood-feeding, autogeny and development of ova; the information which are necessary for the transmission understanding. The principal topic of the thesis is reviewing methods for distinguishing parous and nulliparous females, which are commonly used for four Nematoceran groups: mosquitoes (Culidicade), black flies (Simuliidae), sand flies (Phlebotominae) and biting midges (Ceratopogonidae, the genus Culicoides). The section is focused mainly on family Culicidae, because the methods used for mosquitoes were the groundwork for developing methods suitable for the other groups. Some of the procedures, for example counting folicular dilatations or assessing the condition of tracheoles in the ovaries, are used for most of the studied groups; others, like pigmentation of the abdominal wall in the genus Culicoides, can be used only for one group. Knowledge of the female parity is very important for epidemiological and ecological studies, because only parous females, previously blood-fed on infected hosts, can transmit...
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Interactions of human immune system with saliva of bloodfeeding Nematocera
Jelínková, Kristýna ; Kolářová, Iva (advisor) ; Janda, Jozef (referee)
In humans, the bites of bloodfeeding insects from the suborder Nematocera induce an immune reaction, both humoral and cell-mediated. Some antigens presented in the saliva of some insect families - Psychodidae, Culicidae, Simuliidae and Ceratopogonidae - are studied more deeply to reveal their immunomodulatory and antigennic properties. Most studies are focused on mosquitos (Culicidae) and sand flies (Psychodidae). Mosquito saliva elicits primarily IgG and IgE antibodies. The level of antibodies in the sera of bitten individuals reflects the length and intensitity of previous exposure to insect bites. Anti-saliva IgE antibodies play an important role in response to the mosquito bites and are frequently associated with allergic reactions. On the other hand, sand fly saliva elicits primarily IgG antibodies. Cell-mediated human immune response to mosquito bites is a neglected research topic. It has been proven that the saliva of sand flies (genus Phlebotomus and Lutzomyia) stimulates proliferation of PBMC from repeatedly bitten humans. Cytokine production by human PBMC and expression of costimulatory molecules in human monocytes, macrophages, and dendritic cells are also influenced by the presence of sand fly saliva. So far as we know, there are only few studies on human immune response to black fly...
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Parous and nulliparous female detection in blood-sucking nematocera insects
Mračková, Marie ; Votýpka, Jan (advisor) ; Král, David (referee)
Nematocerous insects belong to the order Diptera, one of the largest and worldwide spread groups of insects. Haematophagous species act not only as tormentors, but also as vectors of various pathogens. The first section of this thesis reviews about insetct's reproductive systems, multiple blood-feeding, autogeny and development of ova; the information which are necessary for the transmission understanding. The principal topic of the thesis is reviewing methods for distinguishing parous and nulliparous females, which are commonly used for four Nematoceran groups: mosquitoes (Culidicade), black flies (Simuliidae), sand flies (Phlebotominae) and biting midges (Ceratopogonidae, the genus Culicoides). The section is focused mainly on family Culicidae, because the methods used for mosquitoes were the groundwork for developing methods suitable for the other groups. Some of the procedures, for example counting folicular dilatations or assessing the condition of tracheoles in the ovaries, are used for most of the studied groups; others, like pigmentation of the abdominal wall in the genus Culicoides, can be used only for one group. Knowledge of the female parity is very important for epidemiological and ecological studies, because only parous females, previously blood-fed on infected hosts, can transmit...
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