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Growth and mortality of natural regeneration after dieback of tree layer of mountain spruce forest
Červený, Jan ; Bače, Radek (advisor) ; Synek, Michal (referee)
The aim of this study is to assess the state of the natural generalization after the death of the upper tree layer in the mountain spruce forest, based on data acquired on permanent research area (50x50 m) where the collection of the data is in progress since 2006 in the area Trojmezná. These areas were damaged by hurricane Kyrill and afterwards bark beetle calamity in 2008. In these areas were defined squares of size 5x5m and they were divided into cells 0,5x0,5m and these shelf is recorded every individual, the increment, health and microhabitat. By the analysis which was carried out, was found, that woody representation is not different from the representation of upper tree layer, the number of spruce is 97% and 3% of the crane. Most individuals were caught before the disturbances, the youngest individuals germinated in 2006. Higher individuals achieve higher gains than smaller individuals, it means that the heterogeneity of the height structure is increasing. Based on analysis of mortality individual squares (50x50m) was found that after the disturbance on TVP new places without trees were not formed. The dependence of mortality on frequency of individuals in the cells (0,5x 0,5m) has not been demonstrated. That means that mortality of individuals at intraspecific competition is yet significantly independent, although abundance exceeded 17 individuals per cell. Eight years after disturbance is mortality very low. The highest regeneration grows up to 20 cm per year.
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Comparative growth characterization of frequently used substrains of the model cyanobacterium Synechocystis sp. PCC 6803 under varying culture conditions
Zavřel, Tomáš ; Očenášová, Petra ; Sinětova, M. A. ; Červený, Jan
Cyanobacteria have gained increased attention as ideal candidates for biotechnological applications due to their capacity to produce valuable molecules ranging from therapeutic proteins to biofuels. Their natural phenotypic plasticity in highly dynamic environments enables easy deployment of new biotechnologies as well as opening possibilities for genetic engineering. This contribution presents a new approach to fast and reliable characterization of cyanobacteria growth in a flat panel photobioreactor that enables examination of changing light, temperature, and nutrient availability. The utilization of semi-continuous automatic cultivation with real-time culture growth monitoring provides a strong experimental basis for both characterization and optimization of cyanobacteria cultures in photobioreactors. We first characterized the autotrophic growth of the substrain of Synechocystis sp. PCC 6803 denoted as GT-L. This strain is capable of efficient growth under a wide range of environmental conditions with doubling time as fast as 5 h under favorable conditions. However, differences among Synechocystis sp. PCC 6803 substrains have been identified on both the genotype and phenotype levels. We therefore aimed to utilize the experimental platform to characterize multiple commonly used Synechocystis sp. PCC 6803 substrains. This method will enable us to identify substrains capable of robust growth and high production yields as reliable biotechnological candidates.
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Development of methods for breeding high-lipidcontent algal strain Chlamydomonas reinhardtii using fluorescence-activated cell sorting
Fedorko, Jan ; Búzová, Diana ; Červený, Jan
Green microalgae are among the most widely distributed microorganisms in the biosphere. They are significant contributors to global photosynthetic productivity and are interesting for biotechnology due to their large variety of high-value compound accumulation and range of applications. To achieve profitable microalgae cultures for biotechnology, one wants to combine antagonistic properties: rapid growth and high accumulation of specific compounds. Here, we focus on development of advanced cultivation strategies and breeding methods applied to the model algae Chlamydomonas reinhardtii for optimized production of lipids. For identification, isolation, and subsequent selection of an optimal subpopulation with high lipid content, we used high-throughput fluorescenceactivated cell sorting in combination with imaging flow cytometry on cells stained with lipid-specific fluorescent dye. We observed that post-sort cell viability was not negatively influenced by external parameters used during the sorting procedure (pressure, light quality and quantity, influence of the sorting electromagnetic field, toxic effects of both fluorescent marker and microfluidic system medium composition).
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Metabolic rhythms of unicellular, nitrogen fixing cyanobacteria and possible interplay with modeled KaiABC circadian oscillator
Červený, Jan ; Nedbal, Ladislav
Circadian clocks of living organisms provide evolutionary advantage and make living in dynamic environment more efficient. The clocks affect human lives and health as well as control the simplest organisms such as prokaryotic cyanobacteria. The cyanobacteria represent an excellent model that is amendable to a multitude of genetic, biochemical, and biophysical methods. The cyanobacterium, Cyanothece sp. ATCC 51142 relies on the circadian clock to permit, in the same cell, anoxygenic nitrogen fixation at night and oxygenic photosynthesis during solar day. We measured real-time, in-situ photosynthetic and respiratory activities as well as the culture growth under light forcing conditions and also under constant light, i.e. free-running mode. Interestingly, the experiments show a strong 24h-period dynamic pattern that is replaced by apparent 12h-period in free running mode. The 24h-pattern does not change significantly when changing the light/dark ratio from 16hL/8hD to 12hL/12hD and 8hL/16hD. Furthermore, we tried to elucidate connection between these metabolic rhythms and known structure of KaiABC circadian oscillator by means of mathematical modeling. One of simulation results show a strong correlation between the presumed catabolic event indicated by significant peak in respiratory activity, and simulated dynamics of KaiB4 complex in modeled circadian pacemaker. A causal relationship between these 2 events is suggested because KaiB4 facilitates dephosphorylation of KaiC6 hexamer, which is known to signal upcoming dark period.
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Modelování a simulace logistických objektů
Šubertová, Alžběta ; Pernica, Petr (advisor) ; Červený, Jan (referee)
Složité podnikatelské prostředí vyžaduje sofistikované nástroje pro podporu rozhodování. Těmito nástroji mohou být právě simulace. Každý podnik je složitý systém, který je nutné nejdříve důkladně poznat a na základě tohoto poznání můžeme vytvořit zjednodušený model. Na tomto modelu pak simulujeme změnu jednotlivých parametrů, vstupních podmínek, hypotéz a předpokladů. Ani simulace nám však nemusí zajistit úspěch v podnikání, nicméně je významnou oporou při výběru jednotlivých rozhodnutí.
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