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Effect of temperature on sand fly biology and Leishmania transmission
Charvátová, Lada ; Sádlová, Jovana (advisor) ; Dvořák, Vít (referee)
and keywords The current rise in air temperature causes a range of global changes, affecting many species of organisms and their interactions. Phlebotomine sand flies are small members of Dipteran insects of the family Psychodidae, subfamily Phlebotominae, transmitting Leishmania, parasitic flagellates (Kinetoplastida: Trypanosomatidae) that cause the important human disease leishmaniasis. Based on the literature review, the external temperature significantly affects the biology of sand flies. High temperature accelerates their metabolism and shortens the growth rate of immature stages, also influencing body size and body weight (faster development in higher temperatures makes them smaller). The time needed for blood digestion is also reduced, and female defecation and oviposition are accelerated. On the other hand, cold temperatures prolong growth, and cause lower emergence of adult sand flies, slower digestion of blood, or number of laid eggs. Very high or very low temperatures can cause diapause in the larval stage or eggs. In general, the optimal temperature to cover all of their physiological needs is 24-28 řC. Temperature impacts the development of Leishmania in sand flies as well, it is likely that Leishmania has a lower optimal temperature as opposed to sand flies, and therefore some...
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Selected proteolytic aspects as targets to combat ticks and tick borne pathogens
HARTMANN, David
Ticks and tick-borne diseases (TBD) represent a growing global burden for both human and animal health. Tick-host-pathogen interactions have evolved through dynamic processes that accommodated the genetic traits of the hosts, pathogens transmitted, and the vector tick species that mediate their development and survival. As in other parasites, proteases and proteolysis have been found as one of the key factors in this interaction triangle. This thesis is focused on selected proteolytic aspects of tick and tick-borne diseases: (i) processing of host blood as a source of nutrients and energy (hematophagy) as a continuum of the long-term goal of the Laboratory of Vector Immunology, that established the currently accepted model of multienzyme degradation of host blood proteins by ticks (ii) proteases in innate immunity (iii) validation of Babesia proteasome as a potential therapeutic target against the tick transmitted apicomplexan parasites.
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Leishmania development in sand flies during bloodmeal digestion
Pružinová, Kateřina ; Volf, Petr (advisor) ; Bates, Paul Andrew (referee) ; Valenzuela, Jesus G. (referee)
This thesis is focused on the bloodmeal digestion of phlebotomine sand flies and its effects on Leishmania development within their midguts. In the first part, we studied various parameters of bloodmeal digestion in four sand fly species differing in susceptibility to Leishmania donovani to evaluate the effects on vector competence. Both proven vectors of L. donovani (Phlebotomus orientalis and P. argentipes) showed lower trypsin activity and slower formation of the peritrophic matrix (PM) than refractory species (P. papatasi and Sergentomyia schwetzi). Remarkably, P. orientalis and P. argentipes strikingly differed from each other in a time course of bloodmeal digestion. Phlebotomus orientalis females showed very slow bloodmeal digestion with low peaks of proteolytic activities and defecated around day five post bloodmeal. In contrast, P. argentipes females digested faster with a very high peak of chymotrypsin activity, their PM was present for only a short time and defecation was finished by day three post bloodmeal. We presume that the period between the degradation of the PM and defecation (i.e. time frame when Leishmania bind to the midgut to avoid expulsion with bloodmeal remnants), is one of crucial parameters affecting the establishment of Leishmania in the sand flies. In both natural...
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Leishmania development in sand flies during bloodmeal digestion
Pružinová, Kateřina
This thesis is focused on the bloodmeal digestion of phlebotomine sand flies and its effects on Leishmania development within their midguts. In the first part, we studied various parameters of bloodmeal digestion in four sand fly species differing in susceptibility to Leishmania donovani to evaluate the effects on vector competence. Both proven vectors of L. donovani (Phlebotomus orientalis and P. argentipes) showed lower trypsin activity and slower formation of the peritrophic matrix (PM) than refractory species (P. papatasi and Sergentomyia schwetzi). Remarkably, P. orientalis and P. argentipes strikingly differed from each other in a time course of bloodmeal digestion. Phlebotomus orientalis females showed very slow bloodmeal digestion with low peaks of proteolytic activities and defecated around day five post bloodmeal. In contrast, P. argentipes females digested faster with a very high peak of chymotrypsin activity, their PM was present for only a short time and defecation was finished by day three post bloodmeal. We presume that the period between the degradation of the PM and defecation (i.e. time frame when Leishmania bind to the midgut to avoid expulsion with bloodmeal remnants), is one of crucial parameters affecting the establishment of Leishmania in the sand flies. In both natural...
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Leishmania development in sand flies during bloodmeal digestion
Pružinová, Kateřina ; Volf, Petr (advisor) ; Bates, Paul Andrew (referee) ; Valenzuela, Jesus G. (referee)
This thesis is focused on the bloodmeal digestion of phlebotomine sand flies and its effects on Leishmania development within their midguts. In the first part, we studied various parameters of bloodmeal digestion in four sand fly species differing in susceptibility to Leishmania donovani to evaluate the effects on vector competence. Both proven vectors of L. donovani (Phlebotomus orientalis and P. argentipes) showed lower trypsin activity and slower formation of the peritrophic matrix (PM) than refractory species (P. papatasi and Sergentomyia schwetzi). Remarkably, P. orientalis and P. argentipes strikingly differed from each other in a time course of bloodmeal digestion. Phlebotomus orientalis females showed very slow bloodmeal digestion with low peaks of proteolytic activities and defecated around day five post bloodmeal. In contrast, P. argentipes females digested faster with a very high peak of chymotrypsin activity, their PM was present for only a short time and defecation was finished by day three post bloodmeal. We presume that the period between the degradation of the PM and defecation (i.e. time frame when Leishmania bind to the midgut to avoid expulsion with bloodmeal remnants), is one of crucial parameters affecting the establishment of Leishmania in the sand flies. In both natural...
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Leishmania development in sand flies during bloodmeal digestion
Pružinová, Kateřina
This thesis is focused on the bloodmeal digestion of phlebotomine sand flies and its effects on Leishmania development within their midguts. In the first part, we studied various parameters of bloodmeal digestion in four sand fly species differing in susceptibility to Leishmania donovani to evaluate the effects on vector competence. Both proven vectors of L. donovani (Phlebotomus orientalis and P. argentipes) showed lower trypsin activity and slower formation of the peritrophic matrix (PM) than refractory species (P. papatasi and Sergentomyia schwetzi). Remarkably, P. orientalis and P. argentipes strikingly differed from each other in a time course of bloodmeal digestion. Phlebotomus orientalis females showed very slow bloodmeal digestion with low peaks of proteolytic activities and defecated around day five post bloodmeal. In contrast, P. argentipes females digested faster with a very high peak of chymotrypsin activity, their PM was present for only a short time and defecation was finished by day three post bloodmeal. We presume that the period between the degradation of the PM and defecation (i.e. time frame when Leishmania bind to the midgut to avoid expulsion with bloodmeal remnants), is one of crucial parameters affecting the establishment of Leishmania in the sand flies. In both natural...
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Bloodmeal digestion of phlebotomine sand flies and its effect on Leishmania development
Pružinová, Kateřina ; Volf, Petr (advisor) ; Šobotník, Jan (referee)
Leishmania development in their vectors is closely connected with bloodmeal digestion. This thesis focuses on factors affecting bloodmeal digestion, egg development and Leishmania infection within the sand fly gut. First, we compared the effect of mammalian (rabbit) and avian (chicken) blood on digestion and eggs development in Phlebotomus duboscqi. Sand flies fed on chickens had twice lower protein concentrations in the midgut and significantly lower trypsin activity compared to those fed on rabbits. The highest differences in the trypsin activity were observed during first 24 hours post bloodmeal. In addition, females fed on chickens had slower eggs development and their eggs were 10 % smaller compared to those fed on rabbits. In the second part of the thesis we tested the effect of mosquito hormone TMOF on the trypsin activity and eggs development of Lutzomyia longipalpis. Rabbit blood with TMOF (28 mg/ml) was presented to the females via a membrane feeding system. Sand flies fed on blood with TMOF had 15 - 35 % less trypsin activity than control females fed on only rabbit blood. In addition, females fed on blood with TMOF had developed 30 % less eggs and their eggs were 12 - 24 % smaller compared to control group. However the effect of TMOF we observed was lower than that described previously...
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