Postnatal functional maturation of blood phagocytes in pig

Developmental changes of functional ability of peripheral blood phagocytes from days 1 to 100 of life were investigated. Luminol enhanced chemiluminiscence was used to establish the ability of phagocytes to produce reactive oxygen species (ROS). Simple superoxide anion production was determined by spectrophotometrical measurement of cytochrome c. Activity of surface aminopeptidase N was assessed by spectrophotometrical measurement of l-alanine-p-nitroanilide. Flow cytometric measurements of CD18 and CD45 expression were performed. The ROS production per 0.5microl of blood did not show any trend; however, the values recalculated per 500 granulocytes had a decreasing course. The most noteworthy increase in production of superoxide anion occurred between days 17 and 26. Activity of aminopeptidase N decreased during the first 4 weeks. Expression of CD18 and CD45 intensively increased from days 1 to 14 with gradual decrease by day 100. Natural immunity develops during the early postnatal life and seems to be influenced by exposure of the organism to environmental antigens.     

The dynamics of glycogen deposition within the parenchyma tissue of Melanozetes meridianus (Acari: Oribatida)

Glycogen deposits were studied in the parenchyma of the oribatid Melanozetes meridianus Sellnick through two years, with respect to food consumption, alimentary tract characteristics and environmental factors. A remarkable peak in the amount of glycogen granules was observed in autumn and early winter, but they were low or absent in spring. The females exhibited a higher density of glycogen granules.     

Long-term animal impact modifies potential production of N<Subscript>2</Subscript>O from pasture soil

At cattle overwintering areas, inputs of nutrients in animal excrements create conditions favourable for intensive microbial activity in soil. During nitrogen transformations, significant amounts of N₂O are released, which makes overwintering areas important sources of N₂O emission. In previous studies, however, increasing intensity of long-term cattle impact did not always increase emissions of N₂O from the soil: in some cases, N₂O emissions from the soil were lower at the most impacted area than at the moderately impacted one. Thus, the relationships between the level of long-term animal impact and potential production of N₂O from soil by denitrification were investigated in field and laboratory experiments. Field measurements indicated that the production of N₂O after glucose and nitrate amendments was greater in severely and moderately impacted locations than in an unimpacted location, while differences between the severely and moderately impacted locations were not significant. In laboratory experiments, the potential production of N₂O (measured as anaerobic production of N₂O after addition of glucose and nitrate) was highest in the moderately impacted soil. Surprisingly, potential N₂O production was lower in the most impacted than in the moderately impacted soil, and the net N₂O production in the highly impacted soil was further decreased by a significant reduction of N₂O to N₂. The expected stimulating effect of an increasing ratio of glucose C to nitrate N on the reduction of N₂O to N₂ during denitrification was not confirmed. The results show that cattle increase the denitrification potential of the soil but suggest that the denitrification potential does not increase indefinitely with increasing cattle impact.     

Transformation of C-labelled lignin and humic substances in forest soil by the saprobic basidiomycetes Gymnopus erythropus and Hypholoma fasciculare

Litter decomposing basidiomycetous fungi produce ligninolytic oxidases and peroxidases which are involved in the transformation of lignin, as well as humic and fulvic acids. The aim of this work was to evaluate their importance in lignin transformation in forest litter. Two litter decomposing basidiomycete species differing in their abilities to degrade lignin - Hypholoma fasciculare, and Gymnopus erythropus - were cultured on sterile or non-sterile oak litter and their transformation of a ¹⁴C-labelled synthetic lignin (dehydrogenation polymer ¹⁴C-DHP) was compared with that of the indigenous litter microflora. Both in sterile and non-sterile litter, colonisation by basidiomycetes led to higher titres of lignocellulose-degrading enzymes, in particular of laccase and Mn-peroxidase (MnP). The titres of the latter were 6 to 40-fold increased in the presence of basidiomycetes compared to non-sterile litter. During 10 weeks, G. erythropus mineralised over 31% of ¹⁴C-DHP in sterile litter and 23% in non-sterile litter compared to 14% in the non-sterile control. Lignin mineralization by H. fasciculare was comparable to the non-sterile control, 12% in sterile litter and 16% in the non-sterile litter. The largest part of ¹⁴C from ¹⁴C-DHP was transformed into humic compounds during litter treatment with both fungi as well as in the control. In addition to the fast lignin mineralization, microcosms containing G. erythropus also showed a lower final content of unaltered lignin and 23-28% of the lignin was converted into water-soluble compounds with relatively low molecular mass (<5 kDa). Both G. erythropus and H. fasciculare were also able to further mineralise humic compounds. During a 10-week fungal treatment of an artificial ¹⁴C-humic acid (¹⁴C-HA) supplemented to the natural humic material of a forest soil, the fungi mineralised 42% and 19% of the labelled material, respectively, under sterile conditions. The ¹⁴C-HA mineralization by introduced basidiomycetes in microcosms containing non-sterile humic material, however, did not significantly differ from that of a non-sterile control and was around 12%. Altogether the results show that saprobic basidiomycetes can considerably differ in their rates of lignin and humic substance conversion. Furthermore, lignin degradation in forest soil can rather slow down by interspecific competition than it is accelerated by cooperation of different microorganisms occupying specific nutritional niches. Therefore, the overall contribution of saprobic basidiomycetes depends on their particular eco-physiological status and the competitive pressure, and may be often lower than initially expected. Significant lignin transformation including partial mineralization is seemingly not exclusively dependent on exceptional high titres of ligninolytic enzymes but also on so far unknown factors. Higher endocellulase production and subsequent weight loss was found in microcosms where saprobic basidiomycetes were combined with indigenous microbes. Potentially, lignin degradation by the basidiomycetes may have increased cellulose availability to the indigenous microbes.     

Distribution of the double-spined spruce bark beetle <Emphasis Type="BoldItalic">Ips duplicatus</Emphasis> in the Czech Republic: spreading in 1997–2009

Ips duplicatus (Coleoptera: Curculionidae) was reported in the Euro-Siberian taiga from Sweden to Sakhalin and in the Alps at the beginning of the 20th Century. It has been recorded in spruce stands in the north-eastern part of the Czech Republic since the beginning of the 1970s; monitoring of I. duplicatus was conducted in the Czech Republic in 9 years between 1997 and 2009. Beetles of the overwintering generation were captured in Theysohn pheromone traps baited with a lure of ipsdienol and E-myrcenol, and after 2005 in ID Ecolure lures. Surprisingly, I. duplicatus was found throughout the Czech Republic already in 1997. In 2002, there was a nationwide decrease in their numbers. Particularly since 2005, there has been a spread from the main center of occurrence in the eastern areas to the south and west into the central part of Bohemia where, until that time, its population densities had been lower and had not caused economically significant damage. Moreover, it was observed that in the north-eastern parts of the Czech Republic up to 80% of spruce trees from sanitary felling had been infested by this pest in recent years. The recorded amount of spruce trees infested by I. duplicatus is correlated significantly with the amount of spruce trees recorded as damaged by Ips typographus, Ips amitinus and Pityogenes chalcographus infestation as well as with the numbers of individuals of I. duplicatus captured during the aforementioned monitoring.     

Comparison of four techniques for plum pox virus detection

Journal of Plant Diseases and Protection - Twenty-four stone fruit trees showing typical symptoms of plum pox virus (PPV) were tested for PPV using ELISA, RT-PCR, real-time RT-PCR and RT-LAMP. The...     

Pollination dynamics in a Douglas-fir seed orchard as revealed by pedigree reconstruction

• ? Pollination dynamics was studied in a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard using 8 nuclear microsatellite markers and pedigree reconstruction.
• ? The seed orchard consisted of 49 parents (clones). Cone-crop management included bloom delay and supplemental mass pollination (SMP) using 12 internal and 4 external pollen donors.
• ? A random sample of 801 bulk seeds was genotyped for both haploid megagametophyte and corresponding diploid embryo.
• ? Using the parental population’s multilocus genotypes, full pedigree reconstruction generated all the information needed to estimate the maternal, paternal, and parental reproductive success, selfing, pollen contamination, and pollination success of the 4 external pollen donors.
• ? Maternal, paternal, and parental reproductive success varied with 80% of gametes being produced by 23, 45, and 37% of the orchard’s parents, respectively, resulting in a drastically reduced effective population size as compared to the census number (14 vs. 53).
• ? Selfing, pollen contamination, and aggregate SMP success (internal and external) were estimated to be 15.2, 10.4, and 15.0%, respectively.
• ? Full pedigree reconstruction was effective in unraveling the orchard’s pollination dynamics and both female and male reproductive success.

     

Influence of latent 'asymptomatic' toxoplasmosis on body weight of pregnant women

The latent toxoplasmosis is usually considered to be asymptomatic, however, this paradigm has never been rigorously tested. Here we searched for symptoms of deterioration of physical health (decrease of weight) in infected people by analysis of clinical records of 758 women tested for toxoplasmosis in the 16th week of gravidity. Toxoplasma-positive women have a lower body weight in the 16th week of gravidity (p = 0.02) than Toxoplasma-negative women. Moreover, a negative correlation between weight and the duration of toxoplasmosis was found in a subset of 174 Toxoplasma-positive women (p = 0.04), suggesting that slow and cumulative effects of latent toxoplasmosis, rather than a transient effect of acute toxoplasmosis, are responsible for the decreased weight of infected subjects. Longer duration of gravidity estimated from the date of last menstruation in the set of Toxoplasma-positive women in the 16th week of gravidity estimated with ultrasonography (p = 0.04) suggests a possibility of retarded foetal growth in Toxoplasma-positive women. The prevalence of latent toxoplasmosis is extremely high. Therefore, even its mild symptoms such as the decreased body weight in Toxoplasma-positive pregnant women might in fact indicate an unrecognized serious public health problem.