National Repository of Grey Literature 132 records found  1 - 10nextend  jump to record: Search took 0.02 seconds. 
Environmental drivers of microbial community composition in a temperate forest
Martinović, Tijana ; Baldrian, Petr (advisor) ; Vašutová, Martina (referee) ; Kopecký, Jan (referee)
Recently, much attention has been focused on the importance of forests to the global carbon cycle. Microorganisms are a critical component of the carbon cycle in forests, participating in important ecosystem processes and degrading various carbon compounds, from simple to highly recalcitrant compounds. However, most studies in this regard have focused on fungi. Only in recent years has it become known that bacteria are also capable of degrading complex plant polymers in soil, and that their contribution to the carbon cycle may be as important as that of fungi. Furthermore, our knowledge of the temporal dynamics of both fungal and bacterial communities is limited, as well as their response to different environmental drivers. The main objective of this dissertation was to fill these knowledge gaps by (1) quantifying the rate of temporal turnover of fungal and bacterial communities in soils of temperate forests, (2) describing the factors that shape fungal communities in spruce and beech stands during their long-term development (stand age), (3) assessing the contribution of fungi and bacteria to the utilisation of different carbon sources in forest soils, and finally (4) describing the development of bacterial communities in response to clearcutting of a spruce stand. The study of microbes...
Microbial communities of soils affected by long-term heavy metal contamination
Průchová, Pavla ; Kopecký, Jan (advisor) ; Matyska Lišková, Petra (referee)
This work is focused on microbial communities living in the soil affected by long-term exposure to heavy metals. The soil was sampled at two sites with different levels of contamination near Příbram. In the samples, respiration rate was measured in vitro after addition of carbon sources and at different levels of cadmium, one of the contaminating metals found in the soil. After the incubation with carbon sources, soil samples were collected for environmental DNA isolation. Gene coding for 16S rRNA in Actinobacteria was amplified from the environmental DNA samples and the amplicon composition was assessed by terminal restriction fragment length polymorphism analysis. The resulting profiles were used to compare actinobacterial communities in both groups of soil samples and in individual treatments. The analysis showed a clear distinction between the two sites differing in the contamination level and shifts in the community composition of various intesity depending on the added substrate.
Effect of ectopic synthesis of mitochondrial uncoupling protein 1 in white adipose tissue on whole-body metabolism in mice
Janovská, Petra ; Kopecký, Jan (advisor) ; Drahota, Zdeněk (referee) ; Kalous, Martin (referee)
The prevention and treatment of obesity is a major problem of health care systems in affluent societies. Metabolism of adipose tissue belongs to the therapeutical targets, since accumulation of adipose tissue is the basis of obesity development. Experiments using transgenic mice with ectopic expression of brown- fat uncoupling protein 1 (UCP1) in white adipose tissue (WAT), verified a concept that obesity could be ameliorated by increasing energy expenditure in WAT. The goal of the experiments of this PhD Thesis was to characterize in detail the phenotype of this unique animal model of obesity resistance. We have shown that mitochondrial uncoupling in WAT resulted in increased oxidation of fatty acids (FA), in face of decreased lipogenesis and induced mitochondrial biogenesis in this tissue. In further studies, we aimed to modulate propensity to obesity be increasing FA oxidation in WAT in response to physiological stimuli. This could be accomplished in response to the combination treatment using n-3 polyunsaturated fatty acids (n-3 PUFA) and mild calorie restriction in mice fed high-fat diet. Synergistic induction of mitochondrial oxidative capacity and lipid catabolism in epididymal WAT was associated with suppression of low-grade inflammation of WAT, which is typical for obesity. The improvement of lipid...
Soil microbial communities in agroecosystems and natural habitats contributing to resistance and resilience of the soil environment
Sarikhani, Ensyeh ; Kopecký, Jan (advisor) ; Demnerová, Kateřina (referee) ; Větrovský, Tomáš (referee)
Ensyeh Sarikhani Soil microbial communities in agroecosystems and natural habitats contributing to resistance and resilience of the soil environment. Summary The control of common scab of potatoes (CS) includes resistant varieties (cultivars), precise fertilization, increase of soil moisture, and chemical treatments. Yet, these management practices do not have common or reproducible results at differing sites. A monitoring study was done in 32 sites to evaluate the relation between CS and biological/chemical soil parameters. Correlations were observed between scab severity and content of nutrients such as Fe, N, and Ca in soil and periderm, and between disease severity and abundance of actinobacteria and total bacteria, together with the pathogenicity determinant, txtB gene (biosynthetic gene of thaxtomin) in both soil and periderm of potatoes. The findings led to novel conclusions, which can help to understand relationships applicable in scab control. Peat and DTPA chelated iron were supplemented to pots filled with soil conducive for CS in order to determine the effects of soil organic matter, iron and pH on CS development. The results were compared with data obtained for a suppressive soil from a nearby field with naturally low CS severity. Both peat and iron supplements decreased CS and the combination...
Role of protein kinase C isoforms in cardioprotective mechanism of chronic hypoxia
Hlaváčková, Markéta ; Novák, František (advisor) ; Kopecký, Jan (referee) ; Novotný, Jiří (referee)
Cardiovascular diseases, particularly acute myocardial infarction, are one of the leading causes of death in developed countries. It is well known that adaptation to chronic intermittent hypobaric hypoxia (IHH) confers long-lasting cardiac protection against acute ischemia/reperfusion injury. Protein kinase C (PKC) appears to play a role in its cardioprotective mechanism since the administration of general PKC inhibitor completely abolished the improvement of ischemic tolerance in IHH hearts. However, the involvement of individual PKC isoforms remains unclear. Therefore, the primary aim of this study was to investigate the potential involvement of PKCδ and PKCε, the most prevalent PKC isoforms in rat heart, in the mechanism of IHH-induced cardioprotection. We showed that IHH up- regulated PKCδ protein in left ventricle, enhanced its phosphorylation on Ser643 and increased its co-localization with markers of mitochondrial and sarcolemmal membranes. PKCδ subcellular redistribution induced by IHH as well as the infarct size-limiting effect of IHH was reversed by acute treatment with PKCδ inhibitor rottlerin. These data support the view that PKCδ plays a significant role in IHH-induced cardioprotection. On the other hand, adaptation to IHH decreased the PKCε total protein level without affecting its...
Development of a new sand fly exposure test to evaluate vector control tools
Willen, Laura Adrienne André ; Volf, Petr (advisor) ; Kopecký, Jan (referee) ; Valenzuela, Jesus G. (referee)
In the Mediterranean basin, human visceral leishmaniasis caused by the protozoan parasite Leishmania infantum is a zoonotic disease that gives rise to 1,200 to 2,000 new cases annually. The domestic dog constitutes its main reservoir, of which some may suffer from a severe chronic disease, canine leishmaniasis (CanL). The sand fly Phlebotomus perniciosus is considered to be the principle vector. Saliva of bloodfeeding vectors of diseases has been used in the past to assess host exposure to vector bites and to evaluate vector control tools. This Ph.D. focused on saliva of P. perniciosus to identify exposure markers that could be used in the preparation of a new vector exposure tool. The first part of this Ph.D. aimed at validating the use of a recombinant salivary protein of P. perniciosus - rSP03B - in endemic settings of CanL. During a cross-sectional study, no significant differences between the antibody (Ab) response against whole saliva or the rSP03B were observed between different regions across the Mediterranean basin. Furthermore, the rSP03B was shown to resemble the native protein. During a subsequent study this protein was used to assess the seasonal dynamics of the canine Ab response to P. perniciosus in an endemic area of L. infantum. This study elucidated that also in a heterogeneous...
Antibiotic rezistance genes in soil actinobacteria
Patrmanová, Tereza ; Kopecký, Jan (advisor) ; Lichá, Irena (referee)
Actinobacteria are important members of the soil ecosystems, where they are involved in organic matter decomposition. It is worth mentioning that their secondary metabolism allows them to produce a variety of different compounds. These compounds include antibiotics, among them aminoglycosides have a place in clinical practice. These antibiotics are significant due to a broad spectrum of activities against both gram-negative and gram-positive bacteria. However, their use currently carries a risk, mainly their toxicity and development of antibiotic resistance in bacteria. Resistance is the cause of low effectiveness of some of those antibiotics. Actinobacteria as aminoglycoside producers must protect themselves from these compounds, so a variety of resistance types was developed, out of which enzymatic inactivation is the most studied one. Actinobacteria have evolved several mechanisms, which contribute to a resistance to the agents with antimicrobial effects. Genes encoding antibiotic resistance are abundant in soil environment. Their variability is influenced by many factors, especially the selection of bacteria in soil contaminated with antibiotics and also with strains originating from human and animal waste. Significant role has a horizontal gene transfer, which allows distribution of resistence...

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