Impact of a juvenile hormone analogue on the anatomy and the frontal gland secretion of Prorhinotermes simplex (Isoptera: Rhinotermitidae)

In termites, juvenile hormone plays a key role in soldier differentiation. To better understand the evolutionary origin of the soldiers, we studied the external and inner morphology of pseudergate-soldier intercastes and neotenic-soldier intercastes formed artificially by the application of juvenile hormone analogue in Prorhinotermes simplex. A majority of these intercastes had a soldier phenotype, whereas the inner anatomy had an intermediary form between two castes or a form specific to intercastes. Our experiments showed that traits of neotenics and soldiers can be shared by the same individuals, although such individuals do not exist naturally in P. simplex, and they have not been reported in other species but in some Termopsidae. Our results reinforce the hypothesis that soldiers may have emerged from soldier neotenics during the evolution of termites.     

Richness of ancient forest plant species indicates suitable habitats for macrofungi

Macrofungal species richness generally increases with forest continuity as does the richness of so-called ancient forest plant species (AFS). Based on this assumption, we examined the ability of AFS to indicate macrofungal diversity in six study areas covering a range of elevations and environments in the Czech Republic. In total, we used data from 106 sampling plots (2,500 m² each) distributed over six types of forest stands reflecting different intensities and temporal stages of forest management. Species composition of vascular plants and macrofungi was recorded by a single inventory and regular 2-year monitoring, respectively. In total, we found 71 AFS and 1,413 macrofungal species, of which 150 were red-listed macrofungal species. We documented that AFS show potential for being used in the prediction of macrofungi species richness, including endangered species, at the local scale (α-diversity). Additionally, we found significant differences in macrofungal species richness depending on study area and type of forest management, which did not, however, derogate the effect of AFS. Spatial congruence between species composition of AFS and macrofungi communities (β-diversity) increased with forest age and decreased with intensity of forest management. If we consider the simplicity of monitoring AFS in comparison to regular monitoring of macrofungi, we found a widely usable tool for estimating macrofungal diversity in all dominant types of managed forest in central Europe. However, we should be aware of the limited ability of AFS to capture macrofungal diversity across a broader spatial context (γ-diversity), especially in areas with a low diversity of AFS.     

Structure–activity study of macropin,a novel antimicrobial peptide from the venom of solitary bee Macropis fulvipes (Hymenoptera: Melittidae)

A novel antimicrobial peptide, designated macropin (MAC‐1) with sequence Gly‐Phe‐Gly‐Met‐Ala‐Leu‐Lys‐Leu‐Leu‐Lys‐Lys‐Val‐Leu‐NH₂, was isolated from the venom of the solitary bee Macropis fulvipes. MAC‐1 exhibited antimicrobial activity against both Gram‐positive and Gram‐negative bacteria, antifungal activity, and moderate hemolytic activity against human red blood cells. A series of macropin analogs were prepared to further evaluate the effect of structural alterations on antimicrobial and hemolytic activities and stability in human serum. The antimicrobial activities of several analogs against pathogenic Pseudomonas aeruginosa were significantly increased while their toxicity against human red blood cells was decreased. The activity enhancement is related to the introduction of either l ‐ or d ‐lysine in selected positions. Furthermore, all‐d analog and analogs with d ‐amino acid residues introduced at the N‐terminal part of the peptide chain exhibited better serum stability than did natural macropin. Data obtained by CD spectroscopy suggest a propensity of the peptide to adopt an amphipathic α‐helical secondary structure in the presence of trifluoroethanol or membrane‐mimicking sodium dodecyl sulfate. In addition, the study elucidates the structure–activity relationship for the effect of d ‐amino acid substitutions in MAC‐1 using NMR spectroscopy. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

Effect of tree species identity and related habitat parameters on understorey bryophytes – interrelationships between bryophyte,soil and tree factors in a 50-year-old experimental forest

Plant and Soil - Overstorey tree species influence both soil properties and microclimate conditions in the forest floor, which in turn can induce changes in ground bryophyte communities. The aim of...     

Effect of pH and dissolved organic matter on the abundance of nirK and nirS denitrifiers in spruce forest soil

Acid N depositions in the Bohemian Forest during the second half of the last century caused enormous soil acidification which led to the leaching of essential nutrients including nitrates. We investigated the effect of dissolved organic matter (DOM) and pH on the abundance of 16S RDNA, nirK and nirS gene copies in four spruce forest sites. Soil samples for molecular based quantification (qPCR) were taken from the organic litter and humus layers. The amounts of dissolved organic carbon (DOC) and dissolved nitrogen (DN) were much lower in highly acidified soils. We found a strong correlation between nirK denitrifiers and the amount of available P (r = 0.83, p < 0.001), which suggested a higher nutrient sensitivity of this group of denitrifying bacteria. Additionally, we found that correlations between the amount of nirK denitrifiers and DOC and pH are exponentional showing two important threshold values, being 4.8 mol kg^?1 and 5, respectively. The amount of nirK denitrifiers rapidly decreased below these values. The amount of nirK and nirS denitrifiers was higher in the organic litter horizon than the organic humus horizon at all sampling sites.     

Early to high medieval colonization and alluvial landscape transformation of the Labe valley (Czech Republic): evaluation of archaeological,pollen and macrofossil evidence

In the High Middle Ages, a wave of landscape transformation which originated in western Europe swept across the east-central part of the subcontinent. In the Czech Republic, this happened during the 13th century and it had the same environmental attributes as in the rest of Europe—a considerable increase in population, vast deforestation resulting in a rapid increase in soil erosion, irreversible changes in forest species composition and overall formation of a cultural landscape. In the Czech Republic, the dynamics of such a radical change are poorly understood because it would require detailed archaeological, historical and palaeoecological insight into developments during the Early Middle Ages—a demand that is mostly not met. The aim of this paper is to fill in this gap. Archaeological and historical data from three early medieval strongholds located in central Bohemia, at Libice nad Cidlinou, Stará Boleslav and Hradi??ko, are summarized and evaluated. The first two sites represent well-known political and religious centres of the early Czech state in the 10 to 11th centuries, while the last was of secondary importance. These archaeological sites have radiocarbon dated pollen and plant macrofossil evidence from oxbow sedimentary sequences which are situated in the immediate vicinity of the strongholds. The issue of fluvial transport of pollen and macrofossils is also discussed. Both pollen and macrofossil data from Hradi??ko show surprisingly small impact of the stronghold on the forested alluvial environment. The vicinity of Stará Boleslav was intensively affected by human activity only during the later 11th century. It has not been possible to trace any impact of the foundation of the stronghold at Libice nad Cidlinou on the landscape. Medieval landscape change began before the 13th century in some places, as shown by the data from Stará Boleslav.