ISB Significant Results

The development of new methods for long-term maintenance of algal and cyanobacterial cultures

Alena Lukešová, Pavel Hrouzek, Jan Kaštovský, Martin Lukeš, David Kaftan

The research was focused on the development and standardization of modern cryopreservation techniques for long-term maintenance of scientifically and biotechnologically important strains of algae to ensure their genetic stability. More than 300 strains of soil algae and cyanobacteria, representatives of main taxonomical and morphological groups, and isolated from different climatic regions have been tested in the Institute of Soil Biology ASCR using different cryopreservation protocols. Mechanisms of cryoinjury (critical damage) of cryopreservation recalcitrant or problematic species (strains) were studied using differencial scanning calorimetry, cryomicroscopy, FluorCam, TEM and GC techniques. The elucidation of some mechanisms resulted in the development of new cryopreservation methods and protocols enabling successful cryopreservation of some cryopreservation recalcitrant strains. Novel encapsulation-dehydration method using different osmotica was found to be very promising for maintenance of problematic strains. Results from the study of the effect of cold acclimation on survival of low (to -40 °C) and ultra-low (to -196 °C) temperatures showed species and strain specific response of algae and could be easily applied in practice. Suitability of different methods for measuring of post-cryopreservation viability and recovery has been tested on most of studied strains. Two novel, non-destructive method were developed, the first one based on digital imaging (Naja Image Analysis) of algal re-growth, the second based on analysing photosynthetic activity and reversibility of photosynthetic apparatus damage using fluorescence kinetic camera (different protocols and parameters were tested and optimized). The results were presented at 9 international conferences.

Emissions of nitrous oxide and methane from pasture soils

Miloslav Šimek, Petr Brůček, Jiří Čuhel, Dana Elhottová, Jaroslav Hynšt, Alica Chroňáková, Václav Krištůfek, Anna Němcová, Hana Šantrůčková, Eva Uhlířová

Nitrous oxide and methane are important so called greenhouse gases which also participate in ozone destruction in stratosphere. Microbial transformations of nitrogen and carbon in soil represent one of major sources of these gases. Pasture soils including cattle overwintering areas were identified as significant source of nitrous oxide as well as methane. High density of animals, accumulation of excrements and changes in soil structure are responsible for production of large quantities of gases subsequently escaping into the atmosphere. Nitrogen and other nutrients accumulate in soil during winter and they are later intensively metabolised by soil microorganisms producing gases especially at favourable conditions (temperature, soil moisture etc.) in spring period when most of the emissions take place, too. This results not only in large nutrient loses from soil but also in a significant pollution of atmosphere by nitrous oxide, methane and other trace gases. An important result of our research, taking into account practical possibilities of reducing nitrous oxide emission, is the finding that nitrous oxide emissions are likely affected by soil pH: at higher pH they decrease relatively while the proportion of harmless molecular nitrogen increases. We also investigate intensively the production of methane by archaeal methanogenes and oxidation of methane in surface soil layer using latest methods and techniques of molecular biology. During last 5 years the results were published in ca 20 publications including 5 in international journals and presented in other 16 contributions at 8 international conferences.

Accumulation of animals in pasture sites creates conditions for acceleration of soil microbial processes and leads to the emissions of greenhouse gases from soils to the atmosphere. Agricultural soils represent a significant source of nitrous oxide and methane emissions.

Gas emissions from soils are regulated by a number of environmental factors. Soil porosity and water content in soil pores represent important regulatory factors. The picture shows determination of water infiltration rate into the pasture soil; chambers for gas flux measurements can be seen in the background.

Contact: prof. Ing. Miloslav Šimek, CSc., tel. +420 385 310 174, +420 723 734 722, email: misim@upb.cas.cz

Diversity of soil microbial community in process of primary succession on post-brown-coal-mining sites

Dana Elhottová, Stanislav Malý, Václav Krištůfek, Alica Chroňáková, Jan Frouz, Jiří Kalčík

New knowledge about qualitative and quantitative changes of soil microbial community in different stage of primary succession on non reclaimed post-brown-coal-mining sites (Velká podkrušnohorská výsypka, Sokolov coal-mining district) were acquired in three-years research. The active pristine as well as died fossil microbial community of freshly exposed spoil substrate (Miocene non toxic lacustrine sediment - Cypris serie) and consequent succession changes of the community in initial (0- 3 years), early (10-12 y.), mid (20-22 y.) and late (42-44 y.) stage were described. The composition of bacterial community in the initial stage indicated an occurrence of species important for biotechnology application. A fundamental qualitative community shift was found ten years after heaping the spoil substrate and consisted in increasing of structural, functional and species diversity. Original results were showed by comparison of community succession changes in surface (0-5 cm) and mineral (10-15 cm) layer. The most important environmental factors responsible for these changes were determined. The community succession patterns exerting in the studied soil ecosystem were designed. The other project gains consisted in the enrichment of methodology suitable for qualitative study of the soil microbial community in situ.

Grazing as a management tool of permanent grasslands in protected landscape areas

Karel Tajovský, Václav Pižl, Josef Starý, Jiří Schlaghamerský, Petr Kment, Igor Malenovský, Květoslav Resl, František Chládek

The results of the research on soil and aboveground invertebrates showed that the grazing management in grasslands do not represent unambiguously negative factor resulting in impoverishment and degradation of given biotopes. Intensive grazing can differently decrease densities of some species of oribatid mites, earthworms, millipedes, terrestrial isopods and other representatives of soil fauna as well as some insect groups related to aboveground vegetation. Intensive pasture eliminates above all the species specifically connected with structural microhabitats on soil surface of non-grazed grasslands; simultaneously it supports spreading of non specific euryvalent invertebrates and can enrich the soil and insect fauna by the species inhabiting the excrements of large herbivores. Less intense grazing and combination of both, mowing and grazing managements result in diversification of habitat conditions in grasslands and contribute to the maintenance of species diversity of soil invertebrate and insect communities, and support thus to conserve natural conditions of the given localities of nature protection importance. The results showed, that both extreme variants of management, i.e. the intense grazing and mowing of large areas, and also abandonment of meadows without any interventions have much more negative effects upon the diversity of protected grasslands than extensive grazing and mowing, and combination of both these management practices.