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Glycocalyx shedding by cercariae of bird schistosomes
Chaloupecká, Jana ; Mikeš, Libor (advisor) ; Štěrba, Ján (referee)
Trichobilharzia spp. are avian schistosomes related to medically important human parasites of the genus Schistosoma. Penetrating cercariae are well known as causative agent of cercarial dermatitis in humans. Cercariae actively penetrate the skin of definitive hosts and transform into schistosomula. This process is preceded by cercarial tail detachment and includes emptying of penetration glands and extensive surface changes. One of these changes is the loss of highly immunogenic glycocalyx which represents a protective coat in the aquatic environment. The glycocalyx has specific composition of saccharide molecules which are bound to lipids or proteins on the membrane of cercarial tegument. There is only limited information about the mechanism of shedding. Hypotheses based on indirect evidences suggest that peptidases or (phospho)lipases from penetration glands could be involved. This work describes the changes in surface glycosylation during transformation of cercariae into schistosomula by fluorescently labelled lectins and monoclonal antibodies against Lewis X antigen. Lectins UEA-I, LTA and PNA have been chosen as markers of transformation of T. regenti. Further, our experiments have been focused on shedding of cercarial glycocalyx. During in vitro induction of penetration gland emptying and...
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Features and functions of glycocalyx of trematode cercariae
Chaloupecká, Jana ; Mikeš, Libor (advisor) ; Kašný, Martin (referee)
Trematodes are parasites from phylum Platyhelminthes which have compex life cycles involving two to four hosts. This work focuses especially on trematodes of the family Schistosomatidae. Their cercariae which leave the snail intermediate host, actively penetrate the skin of definitive hosts and transform into schistosomula. This is accompanied by detachment of cercarial tail and emptying of penetration glands. During transformation, cercarial bodies undergo extensive ultrastructural and molecular changes. One of these changes is the loss of surface glycocalyx which represents a protective coat in the aquatic environment. In glycocalyx shedding, participation of proteolytic enzymes from cercarial penetration glands is expected during invasion of the host. Glycocalyx has specific composition of saccharide molecules which are bound to lipids or proteins on the membrane of cercarial tegument. This work describes the origin, ultrastructure, saccharide composition, function and shedding mechanism of cercarial glycocalyx.
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Glycosylation and antigenic properties of Phlebotomus perniciosus and P. orientalis salivary proteins
Sumová, Petra ; Volf, Petr (advisor) ; Grubhoffer, Libor (referee)
The goal of this study was to map the glycosylation pattern and antigenic properties of the salivary proteins of two closely related sand fly species, Phlebotomus perniciosus and P. orientalis. Affinity blotting with commercially available lectins revealed that many salivary proteins of these species are N-glycosylated, while the presence of O-glycosylation could not be confirmed. The level of N-glycosylation of most of these proteins is quite low, a larger number of potential N-glycosylation sites were found only in the amino acid sequences of P. orientalis hyaluronidase and endonucleases of both species tested. Four antigens from P. perniciosus salivary glands were selected for expression in a bacterial expression system; two of these proteins (PpeSP01 and PpeSP01B) were not glycosylated and the glycosylation level of the remaining two (PpeSP03B and PpeSP07) was low. The antigenic properties of the four chosen recombinant proteins were subsequently tested using immunoblot and ELISA. During the initial experiments with the sera of dogs experimentally bitten by P. perniciosus, two proteins (rSP07 and rSP01B) were proven unsuitable and they were excluded from further experiments. Recombinant proteins rSP03B and rSP01 were recognized by the same IgG antibodies as the native forms of these proteins...
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Glycosylation and antigenic properties of Phlebotomus perniciosus and P. orientalis salivary proteins
Sumová, Petra ; Volf, Petr (advisor) ; Grubhoffer, Libor (referee)
The goal of this study was to map the glycosylation pattern and antigenic properties of the salivary proteins of two closely related sand fly species, Phlebotomus perniciosus and P. orientalis. Affinity blotting with commercially available lectins revealed that many salivary proteins of these species are N-glycosylated, while the presence of O-glycosylation could not be confirmed. The level of N-glycosylation of most of these proteins is quite low, a larger number of potential N-glycosylation sites were found only in the amino acid sequences of P. orientalis hyaluronidase and endonucleases of both species tested. Four antigens from P. perniciosus salivary glands were selected for expression in a bacterial expression system; two of these proteins (PpeSP01 and PpeSP01B) were not glycosylated and the glycosylation level of the remaining two (PpeSP03B and PpeSP07) was low. The antigenic properties of the four chosen recombinant proteins were subsequently tested using immunoblot and ELISA. During the initial experiments with the sera of dogs experimentally bitten by P. perniciosus, two proteins (rSP07 and rSP01B) were proven unsuitable and they were excluded from further experiments. Recombinant proteins rSP03B and rSP01 were recognized by the same IgG antibodies as the native forms of these proteins...
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Structure Analysis of Plant Bifunctional Nuclease TBN1
Kovaľ, Tomáš ; Dohnálek, Jan (advisor) ; Brynda, Jiří (referee) ; Schneider, Bohdan (referee)
This work is dedicated to thorough structural analysis of plant bifunctional nuclease TBN1, the representative of plant nuclease I group. TBN1 along with homologous nucleases from this family plays an important role in plant cell life cycle and also shows considerable anticancerogenic effects. Two variants of TBN1 (wild type and N211D mutant) were studied. Properties of both variants in different solutions were analyzed. Both were successfully crystallized. Structures of both types of TBN1 were solved using X-ray diffraction. The phase problem was solved by Multi-wavelength anomalous dispersion using Zn2+ ions natively present in TBN1. Structural properties of TBN1 such as fold, active site composition, effect of glycosylation and surface electrostatic potential distribution were analyzed. Reaction mechanism of TBN1 was proposed on the basis of structural properties and comparisons with similar structures.
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Glycocalyx shedding by cercariae of bird schistosomes
Chaloupecká, Jana ; Mikeš, Libor (advisor) ; Štěrba, Ján (referee)
Trichobilharzia spp. are avian schistosomes related to medically important human parasites of the genus Schistosoma. Penetrating cercariae are well known as causative agent of cercarial dermatitis in humans. Cercariae actively penetrate the skin of definitive hosts and transform into schistosomula. This process is preceded by cercarial tail detachment and includes emptying of penetration glands and extensive surface changes. One of these changes is the loss of highly immunogenic glycocalyx which represents a protective coat in the aquatic environment. The glycocalyx has specific composition of saccharide molecules which are bound to lipids or proteins on the membrane of cercarial tegument. There is only limited information about the mechanism of shedding. Hypotheses based on indirect evidences suggest that peptidases or (phospho)lipases from penetration glands could be involved. This work describes the changes in surface glycosylation during transformation of cercariae into schistosomula by fluorescently labelled lectins and monoclonal antibodies against Lewis X antigen. Lectins UEA-I, LTA and PNA have been chosen as markers of transformation of T. regenti. Further, our experiments have been focused on shedding of cercarial glycocalyx. During in vitro induction of penetration gland emptying and...
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Features and functions of glycocalyx of trematode cercariae
Chaloupecká, Jana ; Mikeš, Libor (advisor) ; Kašný, Martin (referee)
Trematodes are parasites from phylum Platyhelminthes which have compex life cycles involving two to four hosts. This work focuses especially on trematodes of the family Schistosomatidae. Their cercariae which leave the snail intermediate host, actively penetrate the skin of definitive hosts and transform into schistosomula. This is accompanied by detachment of cercarial tail and emptying of penetration glands. During transformation, cercarial bodies undergo extensive ultrastructural and molecular changes. One of these changes is the loss of surface glycocalyx which represents a protective coat in the aquatic environment. In glycocalyx shedding, participation of proteolytic enzymes from cercarial penetration glands is expected during invasion of the host. Glycocalyx has specific composition of saccharide molecules which are bound to lipids or proteins on the membrane of cercarial tegument. This work describes the origin, ultrastructure, saccharide composition, function and shedding mechanism of cercarial glycocalyx.
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