Influence of Cultivation Conditions on the Sioxanthin Content and Antioxidative Protection Effect of a Crude Extract from the Vegetative Mycelium of Salinispora tropica

Due to their bioavailability, glycosylated carotenoids may have interesting biological effects. Sioxanthin, as a representative of this type of carotenoid, has been identified in marine actinomycetes of the genus Salinispora. This study evaluates, for the first time, the effect of cultivation temperature (T) and light intensity (LI) on the total cellular carotenoid content (TC), antioxidant activity (AA) and sioxanthin content (SX) of a crude extract (CE) from Salinispora tropica biomass in its vegetative state. Treatment-related differences in TC and SX values were statistically significantly and positively affected by T and LI, while AA was most significantly affected by T. In the S. tropica CE, TC correlated well (R² = 0.823) with SX and somewhat less with AA (R² = 0.777). A correlation between AA and SX was found to be less significant (R² = 0.731). The most significant protective effect against oxidative stress was identified in the CE extracted from S. tropica biomass grown at the highest T and LI (CE-C), as was demonstrated using LNCaP and KYSE-30 human cell lines. The CE showed no cytotoxicity against LNCaP and KYSE-30 cell lines.     

Development of forest carbon stock and wood production in the Czech Republic until 2060

? This study describes the scenarios of likely development of carbon pools in managed forest ecosystems of the Czech Republic. The analysis was based on a matrix scenario model (EFISCEN), adopting a novel parameterization based on forest stand site types and forest typology. The model was constrained by practical management rules as prescribed by the Czech Forestry Act and used to assess production potential for the next five decades under three management and three climate scenarios. The analysis provided data on carbon pool development, including both tree biomass and soil compartments.

? For the tested scenarios of sustainable forest management (wood removals not exceeding increment) the model indicated a slight increase of soil carbon pool. For the possibly largest removals (maximum sustainable felling scenario), soil carbon stabilized within two or three decades reaching a mean value of about 8.1 kg/m² for. At the same time, the mean carbon stock held in biomass reached about 10.2 kg/m² including belowground parts. No decline of soil carbon was observed for any of the tested scenarios.

? We conclude that it is reasonable to assume that soil carbon is not a source of carbon under the current management constraints as implemented in the Czech forestry practice.

     

Plant volatile aldehydes as natural insecticides against stored-product beetles

BACKGROUND: Infestation by stored-product pests causes serious losses in food and feed commodities. Among possible strategies against these pests, which aim to reduce the use of synthetic insecticides, including fumigants, natural insecticides produced by plants represent one of the most promising approaches for their ecochemical control. Three six-carbon and nine-carbon aldehydes, natural plant volatiles produced by the plant lipoxygenase pathway, were tested for their insecticidal activity against five species of stored-product beetles in feeding, fumigation and combined bioassays. RESULTS: The compounds (2E,6Z)-nonadienal, (2E)-nonenal and (2E)-hexenal were incorporated into feeding discs in feeding bioassays or evaporated from filter paper in closed glass chambers in fumigation tests. Beetle sensitivity to aldehydes differed according to the different treatments. The highest activity was obtained by (2E)-hexenal in fumigation tests, with the LC(50) ranging from 4 to 26 mg L(-1), while (2E, 6Z)-nonadienal was the most effective in feeding tests, giving LD(50)s ranging from 0.44 to 2.76 mg g(-1) when applied to feeding discs. Fumigation tests in the presence of wheat grains confirmed that (2E)-hexenal was the most effective compound, with a calculated LC(99) ranging from 33 to 166 mg L(-1). CONCLUSION: The results of both feeding and fumigation tests indicated that natural plant aldehydes are potential candidates to control stored-product beetles.     

Molecular evidence of genetic diversity changes in pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.) germplasm after long-term maintenance

Maintaining germplasm genetic integrity is a key objective of long-term ex situ conservation. Periodic regeneration, performed on limited plots with small number of individuals, increases the risk of genetic drift and genetic diversity changes. In this study, six accessions of white flowered, dry seed pea varieties (Pisum sativum L. subsp. sativum var. sativum): Bohatyr, Klatovsky zeleny, Hanák, Moravsky hrotovicky krajovy, Raman and Viktoria-75 and four accessions of colour flowered, fodder pea (P. sativum subsp. sativum var. arvense (L.) Poiret: Arvika, Česky banán, Moravská krajová and Niké, representing Czechoslovak varieties and landraces, bred over the last 40–80 years, were analyzed using ten microsatellite locus specific markers. Each accession was represented by 20 individual seeds of two temporally different samples, spanning the period of 20 or 40 years. Together with intra-accession variation (except of cv. Hanák), evidence of genetic changes, e.g. differences in allele frequencies as well as genetic composition of sample, was detected in six out of ten accessions (Arvika, Bohatyr, Česky banán, Moravsky hrotovicky krajovy, Moravská krajová and Raman). Evidence of genetic erosion was found in three accessions (Česky banán, Moravsky hrotovicky krajovy and Raman), while in another three (Arvika, Bohatyr and Moravská krajová) the level of diversity was found to have increased. Moreover in three samples of Bohatyr (2004) and Klatovsky zeleny (1963 and 2004), low levels of heterozygosity was detected. These results demonstrate that in pea, a self-pollinating and highly homozygous plant, the danger of the loss of genetic integrity exists. These findings are significant for long-term ex situ germplasm management.     

Recent Atmospheric Deposition and its Effects on Sandstone Cliffs in Bohemian Switzerland National Park, Czech Republic

The protected area ??Bohemian Switzerland National Park?? with its characteristic sandstone landscape was influenced by the long-term air pollution and acidic deposition within the area known as Black Triangle (located where Germany, Poland, and the Czech Republic meet, is one of the Europe??s most polluted areas). The local Upper Cretaceous sandstone is subhorizontally stratified, fine- to coarse-grained, quartz dominated, with low content of clay minerals. One of the significant negative effects of the intensive acidic deposition on sandstone outcrops has been identified as chemical (salt) weathering, i.e., a process when the porous sandstone rock is except of chemical influence attacked also by force of crystallization of growing salts crystals. Anions NO ₃ ^? together with SO ₄ ^2? and cation NH ₄ ⁺ were the most abundant solutes in bulk precipitation samples. Current (2002 to 2009) bulk deposition fluxes of SO ₄ ^2? determined at three sites directly in the National Park indicate decline from 23 to 16 kg^?1 ha^?1 year^?1. Infiltration of bulk precipitation solutes into the sandstone mediates the weathering processes. Natural outflow of sandstone pore-water (sandstone percolates) can be sampled only during certain days of year when the sandstone becomes saturated with water and percolates drip out on small number of sites from roofs of overhangs. Under usual conditions percolation water evaporates at the sandstone surface producing salt efflorescences??the typical example is Prav?ická brána Arch locality. The average pH of the dripping sandstone percolates was 3.76. Concentration of SO ₄ ^2? and Al in sandstone percolates reached up to 46 and 10 mg L^?1. The concentration of Al in percolates has been 160-fold greater the one in the precipitation samples suggesting the sandstone as a source. The water O and H isotopic composition of percolates has been virtually identical to precipitation samples, indicating thus relatively short residence time of the solutions within the sandstone pore-spaces. Evaporation experiments with bulk precipitation and percolate samples proved possible origin of some Ca in bulk precipitation and the sandstone rock as the source of Al and possibly of K for the salt efflorescence identified on Rock Arch body.     

Population structure and genetic diversity suggest recent introductions of Dothistroma pini in Slovakia

Dothistroma pini is one of two pathogens causing Dothistroma needle blight (DNB), a foliar disease of pines. The species was redefined in 2004 and subsequently recorded in several European countries. In Slovakia, the first report of the pathogen was in 2013. In this study, the population structure, genetic diversity, and reproductive mode of 105 isolates collected from 10 localities and seven hosts were determined in Slovakia. Species-specific mating type markers, ITS haplotype determination, and 16 microsatellite markers were used to characterize and genotype the isolates. Overall, 15 unique multilocus haplotypes (MLHs) based on microsatellite markers and three ITS haplotypes were identified. Three independent methods (DAPC, STRUCTURE, EDENetwork) separated the isolates into two distinct population clusters corresponding with ITS haplotypes. A high level of clonality was recorded suggesting that conidia are the primary source of pathogen dispersal. The low genetic diversity, predominantly asexual reproductive mode of the pathogen, and the fact that most isolates were collected from introduced tree species and native species in artificially planted urban greenery, supports the hypothesis that D. pini has been recently introduced into Slovakia.     

Effects of simulated drought stress on the fine roots of Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) in a plantation forest on the Kanto Plain,eastern Japan

Drought stress was simulated in a 28-year-old Japanese cedar plantation (Kanto Plain, Japan) between April and October 2004 by removing throughfall using rain shelters. Changes in fine-root parameters caused by this drought treatment were examined by sequential soil coring. Drought effects on fine roots were analyzed separately for particular soil depths (0–5, 5–15, and 15–25 cm) and root diameters (<1 and 1–2 mm). Generally, fine-root biomass and root tip numbers decreased by the drought treatment. Drought stress was most intense for fine roots in the topsoil and weakest for fine roots in the deepest soil layer. Fine roots less than 1 mm in diameter were affected more severely than 1- to 2-mm roots. The effect of drought treatment was most remarkable for the number of white root tips, which decreased to 17% of the control at the soil depth of 0–5 cm. These results suggest that white root tip is the most suitable indicator of drought stress. Simulated drought reduced production of fine roots less than 1 mm and 1–2 mm in diameter. Fine-root mortality was stimulated for roots less than 1 mm, but not for 1- to 2-mm roots. These results suggest that fine roots with larger diameters can survive drought stress at a level simulated in this study, but processes of fine-root production were inhibited regardless of the diameter classes. The duration of drought stress and phenology of fine roots should also be considered in diagnosing the effects of drought on fine-root parameters.     

Determination of optimal rotation period under stochastic wood and carbon prices

The valuation of forest stands is traditionally based on a profit calculus involving revenue from wood sales and associated costs. Currently, the role of carbon management in forests is actively discussed. In a stochastic setting we extend the analysis of the optimal rotation period by considering uncertain revenue streams from carbon trading. We develop a real options model given uncertainties in future wood and CO₂ price behaviour. A detailed sensitivity analysis of the numerical results for both cases – with and without carbon sequestration – is provided. We find that optimal rotation periods vary considerably with (i) the type of price process, (ii) the way how carbon income is defined, and (iii) the selection of discount rates.     

Classification of toxigenic and atoxigenic strains of Aspergillus flavus with hyperspectral imaging

Aspergillus flavus (A. flavus) produces secondary metabolites, aflatoxins, that are harmful to both humans and animals. Because of stringent federal regulation requirements as well as the limitations of available detection methods, there is an urgent need for rapid, non-invasive and effective techniques such as hyperspectral imaging, for the detection of the toxigenic strains of A. flavus. Hyperspectral images of toxigenic and atoxigenic strains of A. flavus were classified. Principal component analysis (PCA) was applied for data decorrelation and dimensionality reduction. A Genetic Algorithm (GA) was implemented for the selection of principal components (PCs) based on Bhattacharya Distance (B-Distance). A Support Vector Machine (SVM) was successfully applied for the classification. Under halogen light sources, in average 83% of the toxigenic fungus pixels and 74% of the atoxigenic fungus pixels were correctly classified; while under UV light sources, 67% of the toxigenic fungus pixels and 85% of the atoxigenic fungus pixels were correctly classified. The pair-wise classification accuracies between toxigenic AF13 and each atoxigenic fungus species (AF38, AF283 and AF2038) were 80%, 91% and 95% under halogen light sources, and 75%, 97% and 99% under UV lights, respectively.     

Fish-isolated strains of Hartmannella vermiformis page, 1967: morphology, phylogeny and molecular diagnosis of the species in tissue lesions

Based on morphological and molecular characterisation, four amoeba strains isolated from organs of freshwater fish were identified as Hartmannella vermiformis Page, 1967. Small subunit rRNA gene sequences of these strains expand the set of corresponding complete and almost complete sequences of this species to twelve. A new species-specific oligonucleotide probe inferred from recently available SSU rRNA gene sequences was designed and successfully tested in tissue lesions produced by one strain of H. vermiformis in experimentally infected fish.