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The Diverged Trypanosome MICOS Complex as a Hub for Mitochondrial Cristae Shaping and Protein Import
HELLER, Jiří
2019 - English
This work deals with MICOS, which stands for mitochondrial contact site and cristae organization system. Until now this multiprotein complex has been analyzed experimentally only in yeast and mammals, who belong to the supergroup Opisthokonta. Our study was done on the parasitic protist T. brucei, a member of the another supergroup called Excavata, which is very diverged from opisthokonts.Thus, it is the very first study done outside of Opisthokonta. This could be very useful in the future for a comparative analysis approach. Our results show that the MICOS complex in T. brucei is composed of 9 subunits, most of which are essential for normal growth. It is required for the maintenance of discoidal cristae that typify excavates such as kinetoplastids and euglenids and mediating the mitochondrial outer and inner membranes contacts. In addition, we discovered that the mitochondrial contact site and cristae organization system may participate in the intermembrane space protein import and help in the oxydative phosphorylation complex formation. It seems that this interesting complex is involved in even more cellular processes. This work deals with MICOS, which stands for mitochondrial contact site and cristae organization system. Until now this multiprotein complex has been analyzed experimentally only in yeast and mammals, who belong to the supergroup Opisthokonta. Our study was done on the parasitic protist T. brucei, a member of the another supergroup called Excavata, which is very diverged from opisthokonts.Thus, it is the very first study done outside of Opisthokonta. This could be very useful in the future for a comparative analysis approach. Our results show that the MICOS complex in T. brucei is composed of 9 subunits, most of which are essential for normal growth. It is required for the maintenance of discoidal cristae that typify excavates such as kinetoplastids and euglenids and mediating the mitochondrial outer and inner membranes contacts. In addition, we discovered that the mitochondrial contact site and cristae organization system may participate in the intermembrane space protein import and help in the oxydative phosphorylation complex formation. It seems that this interesting complex is involved in even more cellular processes.
Keywords:
MICOS; trypanosoma; cristae; mitochondria; protein
Available in the Digital Repository of University of South Bohemia.
The Diverged Trypanosome MICOS Complex as a Hub for Mitochondrial Cristae Shaping and Protein Import
This work deals with MICOS, which stands for mitochondrial contact site and cristae organization system. Until now this multiprotein complex has been analyzed experimentally only in yeast and mammals, ...
The role of Erv1 in the mitochondrial import machinery and iron sulphur cluster export machinery in Trypanosoma brucei
BOUDOVÁ, Michala
2018 - English
Sulfhydryl oxidase Erv1 is a ubiquitous conserved protein of the mitochondrial intermembrane space, which is implicated in mitochondrial protein import as well as in the biogenesis of iron sulphur cluster proteins. While the role of Erv1 is quite well established in higher eukaryotes, Erv1 orthologues of parasitic protists exhibit some structural peculiarities. The study presented in this thesis therefore attempted to elucidate the function of Erv1 in Trypanosoma brucei.
Available in the Digital Repository of University of South Bohemia.
The role of Erv1 in the mitochondrial import machinery and iron sulphur cluster export machinery in Trypanosoma brucei
Sulfhydryl oxidase Erv1 is a ubiquitous conserved protein of the mitochondrial intermembrane space, which is implicated in mitochondrial protein import as well as in the biogenesis of iron sulphur ...
Adipokinetic hormone activities in insect body infected by entomopathogenic nematode
IBRAHIM, Emad Ahmed Sayed
2018 - English
The role of adipokinetic hormone (AKH) in the firebug Pyrrhocoris apterus adults infected by the entomopathogenic nematode (EPN) Steinernema carpocapsae was examined in this study. It was found that co-application of EPN and AKH enhanced firebug mortality about 2.5 times within 24 h (from 20 to 51% in EPN vs. EPN + AKH treatments), and resulted in metabolism intensification, as carbon dioxide production in firebugs increased about 2.1 and 1.6 times compared to control- and EPN-treated insects, respectively. Accordingly, firebugs with reduced expression of AKH receptors showed a significantly lower mortality (by 1.6 to 2.9-folds), and lower general metabolism after EPN + AKH treatments. In addition, EPN application increased Akh gene expression in the corpora cardiaca (1.6 times), AKH level in the corpora cardiaca (1.3 times) and haemolymph (1.7 times), and lipid and carbohydrate amounts in the haemolymph. Thus, the outcomes of the present study demonstrate involvement of AKH into the antistress reaction elicited by the nematobacterial infection. The exact mechanism by which AKH acts is unknown, but results suggested that the increase of metabolism and nutrient amounts in haemolymph might play a role. The role of adipokinetic hormone (AKH) in the firebug Pyrrhocoris apterus adults infected by the entomopathogenic nematode (EPN) Steinernema carpocapsae was examined in this study. It was found that co-application of EPN and AKH enhanced firebug mortality about 2.5 times within 24 h (from 20 to 51% in EPN vs. EPN + AKH treatments), and resulted in metabolism intensification, as carbon dioxide production in firebugs increased about 2.1 and 1.6 times compared to control- and EPN-treated insects, respectively. Accordingly, firebugs with reduced expression of AKH receptors showed a significantly lower mortality (by 1.6 to 2.9-folds), and lower general metabolism after EPN + AKH treatments. In addition, EPN application increased Akh gene expression in the corpora cardiaca (1.6 times), AKH level in the corpora cardiaca (1.3 times) and haemolymph (1.7 times), and lipid and carbohydrate amounts in the haemolymph. Thus, the outcomes of the present study demonstrate involvement of AKH into the antistress reaction elicited by the nematobacterial infection. The exact mechanism by which AKH acts is unknown, but results suggested that the increase of metabolism and nutrient amounts in haemolymph might play a role.
Keywords:
Mortality; Akh gene expression; AKH receptor; Metabolism; RNAi; Pyrrhocoris apterus
Available in the Digital Repository of University of South Bohemia.
Adipokinetic hormone activities in insect body infected by entomopathogenic nematode
The role of adipokinetic hormone (AKH) in the firebug Pyrrhocoris apterus adults infected by the entomopathogenic nematode (EPN) Steinernema carpocapsae was examined in this study. It was found that ...
Victims of agricultural intensification: Mowing date affects Rhinanthus spp. regeneration and fruit ripening.
BLAŽEK, Petr
2018 - English
The recent population declines of annual hemiparasitic Rhinanthus species may be a result of changes in mowing dates associated with the intensification of grassland management, but the causal mechanisms are not well understood. This thesis describes the dynamics of Rhinanthus spp. regeneration after cutting and of fruit ripening under silage or hay making, and suggest recommendations for conservation of the target species. The recent population declines of annual hemiparasitic Rhinanthus species may be a result of changes in mowing dates associated with the intensification of grassland management, but the causal mechanisms are not well understood. This thesis describes the dynamics of Rhinanthus spp. regeneration after cutting and of fruit ripening under silage or hay making, and suggest recommendations for conservation of the target species.
Keywords:
Yellow rattle; Hemiparasite; Agri-environmental schemes; Agricultural intensification; Delayed mowing.
Available in the Digital Repository of University of South Bohemia.
Victims of agricultural intensification: Mowing date affects Rhinanthus spp. regeneration and fruit ripening.
The recent population declines of annual hemiparasitic Rhinanthus species may be a result of changes in mowing dates associated with the intensification of grassland management, but the causal ...
No indication of arthropod-vectored viruses in mosquitoes (Diptera: Culicidae) collected on Greenland and Svalbard.
MÜLLEROVÁ, Jana
2018 - English
Arboviruses are a large polyphyletic group of viruses being transmitted from arthropod vectors to vertebrate hosts. They are important human and animal pathogens. Among the most famous representatives of arboviruses include the Tick-borne encephalitis virus (TBEV), Dengue virus (DV), Zika virus (ZIKV) or Rift Valley fever virus (RVFV) etc. They are studied in tropical and temperate zones abundantly. However, in polar regions there are no traces of such viruses, despite climate change and the migration of vectors to higher latitudes. Therefore, the knowledge of potential worldwide occurrences of arboviruses is important due to their potential to be pathogenic for humans. Arboviruses were detected in many countries such as Alaska, Norway, Canada and in North America, but never in Svalbard nor in Greenland. This research study was focused on the monitoring of arboviruses in north Atlantic areas. Thousands of samples from the mosquito species Aedes nigripes were examined, both from Greenland and from Svalbard (collected during the years 2012-2016). I tested these samples for the presence of different arboviral genera; Orthobunyavirus, Orbivirus, Flavivirus, Alphavirus, Phlebovirus. No presence of arboviruses in examined mosquitoes were detected. These results may reflect an absence of arboviruses, or their prevalence is under the detection limit of our screening in areas studied.
Available in the Digital Repository of University of South Bohemia.
No indication of arthropod-vectored viruses in mosquitoes (Diptera: Culicidae) collected on Greenland and Svalbard.
Arboviruses are a large polyphyletic group of viruses being transmitted from arthropod vectors to vertebrate hosts. They are important human and animal pathogens. Among the most famous representatives ...
Genome stability of human induced pluripotent stem cells
ŘEHÁKOVÁ, Daniela
2018 - English
Lidské indukované pluripotentní kmenové buňky (hiPSCs) nabízejí využití v regenerativní medicíně i modelování onemocnění. Je ovšem podstatné, aby jejich genom zůstal nezměněn a jejich mechanismy opravy DNA byly funkční. V této práci se soustředím na detekci dvouřetězcových zlomů DNA (DSBs) pomocí fosforylovaného histonu H2AX a proteinu 53BP1, a to v několika liniích hiPSCs, jejich zdrojových buňkách, lidských embryonálních kmenových buňkách a buňkách diferencovaných z hiPSCs. sledovala jsem spontánně vytvořené DSB během procesů reprogramace, dlouhodobé kultivace a diferenciace. Pro porovnání reparační kapacity jsem vyvolala poškození pomocí gamma záření a sledovala snížení množství zlomů v čase. Množství ohnisek tvořených sledovanými proteiny bylo sledováno pomocí fluorescenční mikroskopie odděleně pro G1 a S/G2 fázi buněčného cyklu. Zdrojové buňky obsahovaly nízké množství DSBs nesouvisejících s replikací, jejich počet se zvýšil po reprogramaci do hiPSCs a snížil s dlouhodobou kultivací či diferenciácí. Indukce zlomů odhalila, že replikační mechanismy fungují dobře ve zdrojových buňkách a hiPSCs o nízké pasáži, ovšem částečně selhává u hiPSCs ve vysoké pasáži. Tato pozorování naznačují, že buněčné přeprogramování zvýší množství DSBs, ovšem reparační mechanismy fungují. Dlouhodobou kultivací se však schopnost opravovat DSBs snižuje. Human induced pluripotent stem cells (hiPSCs) play roles in both disease modeling and regenerative medicine. It is critical that the genomic integrity of the cells remains intact and that the DNA repair systems are fully functional. I focused on the detection of DNA double-strand breaks (DSBs) by phosphorylated histone H2AX (known as H2AX) and p53-binding protein 1 (53BP1) in multiple lines of hiPSCs, their source cells, human embryonic stem cells (hESCs) and cells differentiated from hiPSCs. I measured spontaneously occurring DSBs throughout the process of reprogramming and during long-term in vitro culture and differentiation process. To assess the variations in the functionality of the DNA repair system among the samples, the number of DSBs induced by gamma irradiation and the decrease over time was analyzed. The foci number was detected by fluorescence microscopy separately for the G1 and S/G2 cell cycle phases. Source cells contained a low number of non-replication-related foci, while this number increased after reprogramming into hiPSCs and then decreased again after long-term in vitro passaging or differentiation. The artificial induction of DSBs revealed that the repair mechanisms function well in the source cells and hiPSCs at low passages but fail to recognize a substantial proportion of DSBs at high passages. Observations suggest that cellular reprogramming increases the DSB number but that the repair mechanism functions well. However, with long-term hipSCs culture reparation capacity decreases.
Keywords:
iPSCs; kmenové buňky; dvouřetězové zlomy; dlouhodobá kultivace; H2AX
Available in the Digital Repository of University of South Bohemia.
Genome stability of human induced pluripotent stem cells
Lidské indukované pluripotentní kmenové buňky (hiPSCs) nabízejí využití v regenerativní medicíně i modelování onemocnění. Je ovšem podstatné, aby jejich genom zůstal nezměněn a jejich mechanismy ...
Fragment analysis represents a suitable approach for the detection of hotspot c.7541_7542delCT NOTCH1 mutation in chronic lymphocytic leukemia
VONKOVÁ, Barbara
2018 - English
Chronic lymphocytic leukemia is the most common type of leukemia in adults in western countries. Despite the continual improvement of diagnostic methods and treatment, it still remains incurable. One of the main characteristic features of CLL is its clinical and biological variability. In present, the analysis of prognostic genetic markers is the most useful tool for understanding biology and clinical course of the disease and consequently the individual type of treatment. The presence of a NOTCH1 mutation is connected with shortened survival and resistance to conventional chemo-immunotherapy. In this thesis, we examined CLL patients with c.7541_7542delCT NOTCH1 mutation and the most sensitive and specific method was identified. We compared nowadays most commonly used methods: allele-specific PCR, fragment analysis and Sanger sequencing. Chronic lymphocytic leukemia is the most common type of leukemia in adults in western countries. Despite the continual improvement of diagnostic methods and treatment, it still remains incurable. One of the main characteristic features of CLL is its clinical and biological variability. In present, the analysis of prognostic genetic markers is the most useful tool for understanding biology and clinical course of the disease and consequently the individual type of treatment. The presence of a NOTCH1 mutation is connected with shortened survival and resistance to conventional chemo-immunotherapy. In this thesis, we examined CLL patients with c.7541_7542delCT NOTCH1 mutation and the most sensitive and specific method was identified. We compared nowadays most commonly used methods: allele-specific PCR, fragment analysis and Sanger sequencing.
Keywords:
CLL; NOTCH1 mutation; fragment analysis; sequencing; allele-specific PCR
Available in the Digital Repository of University of South Bohemia.
Fragment analysis represents a suitable approach for the detection of hotspot c.7541_7542delCT NOTCH1 mutation in chronic lymphocytic leukemia
Chronic lymphocytic leukemia is the most common type of leukemia in adults in western countries. Despite the continual improvement of diagnostic methods and treatment, it still remains incurable. One ...
Anti-tumour necrosis factor activity in saliva of various tick species and its appearance during the feeding period
REZKOVÁ, Markéta
2018 - English
Tumour necrosis factor (TNF) is one of the most important pro-inflammatory cytokines of the innate immune system. We compared the presence of anti-TNF activity in saliva or salivary gland extract from 11 tick species from the family Ixodidae and demonstrated it in genera Ixodes and Haemaphysalis. We also tested dynamics of this specific activity in Ixodes ricinus saliva. The highest effect of saliva appears at the end of feeding period. Significance of anti-TNF activity for tick feeding and transmission of tick-borne pathogens is discussed. Tumour necrosis factor (TNF) is one of the most important pro-inflammatory cytokines of the innate immune system. We compared the presence of anti-TNF activity in saliva or salivary gland extract from 11 tick species from the family Ixodidae and demonstrated it in genera Ixodes and Haemaphysalis. We also tested dynamics of this specific activity in Ixodes ricinus saliva. The highest effect of saliva appears at the end of feeding period. Significance of anti-TNF activity for tick feeding and transmission of tick-borne pathogens is discussed.
Keywords:
ixodid ticks; cytokine; immunomodulation
Available in the Digital Repository of University of South Bohemia.
Anti-tumour necrosis factor activity in saliva of various tick species and its appearance during the feeding period
Tumour necrosis factor (TNF) is one of the most important pro-inflammatory cytokines of the innate immune system. We compared the presence of anti-TNF activity in saliva or salivary gland extract ...
Klíčové faktory složení společenstva sinic dostřikové zóny na dvou chorvatských ostrovech
VONDRÁŠKOVÁ, Alžběta
2018 - English
On two Croatian islands, Veruda and Ugljan, cyanobacterial communities and their composition were surveyed. The cyanobacterial composition in the splash zone was examined in horizontal and vertical directions. Statistical analysis shows the vertical gradient as the strongest one on the contrary the horizontal distribution does not reflect any pronounced differences between the islands. The species diversity and distribution is not dependent on the orientation of the locality toward the cardinal points. The study highlights the importance of high-density sampling in the vertical and also the horizontal direction for covering sufficiently the species richness of the site.
Keywords:
biofilm; Croatian coast; endolithic; epilithic; marine shore; zonation
Available in the Digital Repository of University of South Bohemia.
Klíčové faktory složení společenstva sinic dostřikové zóny na dvou chorvatských ostrovech
On two Croatian islands, Veruda and Ugljan, cyanobacterial communities and their composition were surveyed. The cyanobacterial composition in the splash zone was examined in horizontal and vertical ...
Legionella Becoming a Mutualist: Adaptive Processes Shaping the Genome of Symbiont in the Louse Polyplax serrata
ŘÍHOVÁ, Jana
2017 - English
Genomic modifications coupled with the first known transition of a Legionella bacterium to symbiosis with insects (louse Polyplax serrata). Apart from characteristics typical for other obligatory symbionts in insect (genome reduction), the main innovation of the genome consists in horizontal acquisition of complete biotin operon. Comparative genomic analysis with free living legionellae and other symbiotic bacteria demonstrates convergent evolution of several phylogenetically unrelated louse symbionts.
Keywords:
endosymbiont; Legionella polyplacis; Polyplax serrata; horizontal gene transfer; genome evolution; metabolism
Available in the Digital Repository of University of South Bohemia.
Legionella Becoming a Mutualist: Adaptive Processes Shaping the Genome of Symbiont in the Louse Polyplax serrata
Genomic modifications coupled with the first known transition of a Legionella bacterium to symbiosis with insects (louse Polyplax serrata). Apart from characteristics typical for other obligatory ...
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