National Repository of Grey Literature 65 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Vliv kombinace biouhlu a zinečnatých nanočástic na rostliny kukuřice seté kultivovaných v in vitro podmínkách
Szomolaiová, Erika
Combined application of zinc oxide nanoparticles (ZnO NPs) and biochar could be a perspective tool for enhancing plant viability and mitigating a large scale of stresses in crops. To investigate effect of different concentrations of ZnO NPs (0, 50, 100 and 1000 mg/L), biochar, and their combination on corn plants (Zea mays L.), in vitro experiment took place. Zinc uptake in form of zinc NPs and possible effect of biochar on zinc uptake and accumulation were determined by atomic absorption spectrometry. A positive correlation between ZnO NPs concentration and zinc content in shoots was identified. There was no significant difference observed in plants treated with biochar. Physiological state of plants was evaluated by spectrophotometric analysis of photosynthetic pigments and secondary metabolites. The most significant effect was observed in content of phenolic compounds that increased with increasing ZnO NPs concentration. On the contrary, presence of biochar resulted in significant decrease (p < 0,05) of polyphenols.
Ambrosia galls - neglected model of fungus farming evolution
Zelinková, Barbora ; Kolařík, Miroslav (advisor) ; Janšta, Petr (referee)
Ambrosia galls are a unique type of insect gall created by Cecidomyiidae gall midges. Their association with a fungal symbiont, which forms a layer of ambrosia mycelium inside the gall is unique and reminiscent of fungal farming in other insect groups. To date, not much research has been done on the individual components of ambrosia galls: the galling insect, the symbiotic fungus, and the host plant. This paper provides an insight into fungal farming insects, a description of the ambrosia gall midges and their fungal symbiont, an overview of the mechanisms of each component on gall initiation and the relationships between them, and finally, explores the possible influence of fungal secondary metabolites. The bachelor thesis puts into context long-known and newly acquired information on the mutual interactions and shows that the previously accepted functions are not precise and that each component of the ambrosia gall is partially involved in its formation. Key words: ambrosia gall midges, nutritive mycelium, fungus farming, host specialization, species diversity, phyto-mycophagy, trophic interactions, Cecidomyiidae, Botryosphaeria dothidea, secondary metabolites
Secondary Metabolits of Bryophytes
Štěpán, Michal ; Soldán, Zdeněk (advisor) ; Skýbová, Jana (referee)
The bryophytes are a very old group of plants that are credited with being the first to make the transition to land. To make this land transition possible, plants needed to develop strategies to combat various external environmental factors. And these means, to effectively combat the struggle on land, are various secondary metabolites. It goes without saying that the development of various protective mechanisms did not end there. In the conditions in which mosses live, they need to fight against various fungi and bacteria. In the fight against these organisms, they also use various secondary metabolites, of course. Moss secondary metabolites are a very interesting and understudied field. In this work, information regarding secondary metabolites of bryophytes and their analysis as well as the possible uses of isolated secondary metabolites are included. The beginnings of secondary metabolite research are covered, from one of the first terpenes isolated, which was marchantin in Marchantia polymorpha, to present-day studies focusing on the discovery of new secondary metabolites directly in selected representatives of bryophytes and, of course, their applicability in human activities. It has been confirmed from various international publications that bryophytes produce specific secondary metabolites...
Allelopathy in constitution of plant communities
Kučera, Pavel ; Weiser, Martin (advisor) ; Hadincová, Věroslava (referee)
Allelopathy, the ability of some plants to decrease the fitness of other plants by secondary metabolites, has been known for a very long time. The scientific community paid great attention to its research. Despite this, there is still a lot of ambiguity surrounding this phenomenon. In the past, the role of allelopathy in the constitution of plant communities had been often overlooked. The situation improved slightly in the past years. Several new articles summarizing information about the ecological aspect of allelopathy have been published. However, there are many unanswered questions about its widespread in plant communities and the degree of its influence on the ecosystem. This bachelor thesis is focused on summarizing contemporary knowledge about the influence of allelopathy, mainly from the ecological viewpoint, and presenting possible directions for future research. There is included a short list of the most common allelochemicals, basic principles of the functioning of allelopathy, its widespread through plant taxa, and its effect on the plant communities, mutualistic microorganisms, and the whole ecosystem. There is also mentioned the role of allelopathy in the process of invasion of alien species and at the end of the thesis, I discussed possible utilization of accumulated information in...
Allelopathy of aquatic plants and its possible application to control cyanobacterial blooms
Kolářová, Anna ; Jandová, Kateřina (advisor) ; Kučerová, Andrea (referee)
The excessive growth of phytoplankton and the development of water bloom leading to the damage to aquatic ecosystems are becoming a more and more frequent problem. There are many methods to control the water bloom from which mainly those that use interactions of living organisms have been developing lately, with the utilisation of aquatic plant allelopathy being one of them. Allelopathy is a type of relationship between two organisms when one of them influences the other by secreting allelopathically active compounds in the environment. However, the effect of these secondary metabolites depends on many biotic and abiotic factors, which also has consequences for their potential use to control the water bloom. Although the results of many studies suggest that allelopathy can affect the community of phytoplankton, its role in aquatic ecosystems is still unclear. This thesis summarizes the knowledge about the occurrence of allelopathy among aquatic organisms, the modes of action of allelochemicals and the impacts of the key factors influencing the allelopathic effect. At the same time, it evaluates the prospects of using the allelopathy of aquatic plants to control water bloom and reviews experimental approaches to studying allelopathic interactions.
Preparation of genetically manipulated producers of hybrid manumycins
Krýslová, Dita ; Petříčková, Kateřina (advisor) ; Doubravová, Linda (referee)
Streptomyces are one of the most prolific producers of various secondary metabolites. Manumycin antibiotics represent an important class of these compounds. They belong to a big class of polyketide metabolites. While their antibiotic effect is not very significant, their other biological properties have a big potential in the treatment of inflammations, tumors, etc. They are characterized by two short polyketide chains, which are attached to a central subunit. At the end of the lower polyketide chain, a C5N cyclic unit is frequently attached. This thesis originates from the colabomycin E, an antibiotic, which was discovered by our team. This antibiotic is a new member of manumycin-type metabolites and is produced by Streptomyces aureus SOK1/5-04 strain. Previous studies on the function of individual genes in the biosynthetic gene cluster of colabomycin E inspired us to consider editing of the current biological activity of colabomycin E by replacement of the C5N unit with another, structurally similar bioactive subunit. Due to high structural similarity, we have selected 4,7- dihydroxycoumarin unit of novobiocin, an aminocoumarin-type metabolite produced also by Streptomyces. The 4,7-dihydroxycoumarin unit is pharmacophore with a cancerostatic activity. We expected that the cancerostatic activity...
Alkaloid isolation from Vinca minor and their biological activity II.
Míšek, Vít ; Hošťálková, Anna (advisor) ; Chlebek, Jakub (referee)
Míšek, V.: Alkaloid isolation from Vinca minor and their biological activity II. Diploma thesis, Faculty of Pharmacy in Hradec Králové, Charles University, Department of Pharmacognosy and Pharmaceutical Botany, Hradec Králové, 2023 Supervisor: PharmDr. Anna Hošťálková, Ph.D. Key words: secondary metabolites, Apocynaceae, Vinca minor, cholinesterases, cytotoxicity, alkaloids, isolation, biological activity Alzheimer's disease (AD) is a neurodegenerative disease characterized by the progressive development of cognitive dysfunction, impact on normal daily functions and neuropsychiatric symptoms. There is a limited number of compounds for pharmacotherapy AD, moreover, AD cannot be treated causally. Therefore, research focused on the discovery of new active substances, including natural origin ones, could be one of the possible options for widening the pool of substances used in AD treatment. An extract was prepared by extracting the aerial parts of Vinca minor L. with ethanol and subsequent liquid-luquid extractin at different pH. Using column and preparative thin layer chromatography, this extract was further processed to isolate individual alkaloids. The structure of isolated alkaloids was determined by spectrometric methods (GC/MS and NMR). After comparing the obtained structures with the literature...
Detection of iron-induced proteins and their effect on anthracycline production in submerged culture of Streptomyces coeruleorubidus
In this bachelor's thesis, proteins from the group of enzymes - esterases and their possible induction after the addition of iron to the culture medium were analyzed. Furthermore, the effect of the addition of Fe2+ cations on daunomycin production under submersion cultivation conditions of Streptomyces coeruleorubidus culture was evaluated. The work is divided into two parts. The first part introduced the genus actinobacteria called Streptomyces, their occurrence, properties and possible benefits due to the production of secondary metabolites. In the second, experimental part, the use of the Streptomyces coeruleorubidus strain was described. The effect of iron addition was evaluated by HPLC analysis and native polyacrylamide electrophoresis (native PAGE). HPLC analysis showed that the addition of iron in the form of FeSO4 to the medium increased daunomycin production by approximately 21.5-fold. During native PAGE and after staining, proteins, i.e. esterases, most likely from the groups of and esterases, were detected. Those were more or to a greater extent produced by the Streptomyces coeruleorubidus if the medium contained iron.
Occurrence of the cALAs gene in the BCCO Actinomycetes collection and cultivation improvements for the overproduction of secondary metabolites in soil associated Actinomycetes
Metabolites produced by Bacteria are known to have a wide range of biological activities, which are applied in various fields, like medicine. Most of them are synthesized by members of the group Actinomycetes, in particular from the genus Streptomyces. This thesis deals with the screening process of various Streptomyces strains for a specific gene which is involved in the synthesis of a manumycin-like secondary metabolite. Another aspect discussed here is how the addition of agar to the fermentation media and the pH value can influence the synthesis of bioactive metabolites. To determine the effectiveness of the metabolites various experiments were conducted.
Složení společenstev endoyfytických mikroorganismů osídlujících listy hemiparazitických rostlin
This bachelor´s thesis focuses on describing the community composition of endophytic microorganisms colonizing foliar parts of selected Central-Europaean species of parasitic plants and their potential hosts. The aim is to find specific differences in the structure and diversity of bacterial and fungal endophytes between plant species with parasitic and non-parasitic life strategy.

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