Comparison of cadmium and copper effect on phenolic metabolism, mineral nutrients and stress-related parameters in Matricaria chamomilla plants

Cadmium and copper uptake and its consequence for activity of selected enzymes of phenolic metabolism, phenolic acids accumulation, quantity of mineral nutrients and stress-related parameters in Matricaria chamomilla plants exposed to 60 μM and 120 μM for 7 days has been studied. Cu content in the above-ground biomass was ca. 10-fold lower compared to Cd and amount of Cd in the methanol-soluble fraction was lower than in the water-soluble fraction. “Intra-root” Cd represented 68% and 63% of total Cd content at 60 μM and 120 μM, but no difference was observed in Cu-exposed roots. Cu excess had more pronounced effect on shikimate dehydrogenase, cinnamyl alcohol dehydrogenase, polyphenol oxidase and ascorbate peroxidase activity mainly in the roots. Among eight detected benzoic acid derivatives and four cinnamic acid derivatives, the latter were preferentially accumulated in response to Cd excess. Content of salicylic acid increased in all variants. Amount of superoxide was elevated in both the rosettes (preferentially by Cu) and roots (preferentially by Cd). Accumulation of Ca and Mg was not affected by excess of metals, while potassium decreased in both the rosettes and roots (Cu caused stronger depletion). Amount of Fe increased in the roots in response to both metals (more expressively in Cu-treated ones). Present study using other metabolic parameters (and supplementing our previous studies) has confirmed higher Cu toxicity for chamomile plants, to support its strong pro-oxidant properties. These observations as complex metabolic responses are discussed.     

Ion channels in plants: From bioelectricity,via signaling,to behavioral actions

In his recent opus magnum review paper published in the October issue of Physiology Reviews, Rainer Hedrich summarized the field of plant ion channels.¹ He started from the earliest electric recordings initiated by Charles Darwin of carnivorous Dionaea muscipula,^1,2 known as Venus flytrap, and covered the topic extensively up to the most recent discoveries on Shaker-type potassium channels, anion channels of SLAC/SLAH families, and ligand-activated channels of glutamate receptor-like type (GLR) and cyclic nucleotide-gated channels (CNGC).¹     

Clonal behaviour in closely related plants

The comparison of published data on clonal morphology of closely related species and/or data on comparative morphology of larger groups of related species showed that most of the variation observed is more related to history than to putative selection pressures within present plant communities. Historical factors include both phylogeny and climatic conditions experienced in the past. Inheritance of clonal growth traits is variable even within one genus and is hard to predict namely in polyploid groups. Community parameters and architectural traits may be closely related in the case of hybrid speciation when the divergence of newly formed taxa may be very rapid and easily influenced by short term community parameters; however there are very few well documented examples.     

The effect of humic substances on germination and early growth of Lamb’s Quarters (<Emphasis Type="Italic">Chenopodium album</Emphasis> agg.)

In order to understand the biological activity of humic substances (HS), the effect of four humic acids (HA) and one fulvic acid (FA) on seed germination and early growth of cosmopolitan weed Chenopodium album agg. were tested. Humic substances of diverse origin were used, namely purified commercial HA, HA isolated from lignite, cambisol and podzol, and FA from mountain spruce forest soil. Data processing by two-way ANOVA has shown that type of the tested substances was a more important factor on seed development than used concentration. The major differences in germination and length of shoots were found in the first days of the experiment. Commercial and lignite HA stimulated the seed germination and growth, while podzol HA inhibited them. After this initial phase, all humic substances stimulated the seed development, but these stimulations were not significant (P < 0.05). At the end of germination test, the greatest stimulation effect (up to 20%) was achieved with the lignite HA.     

<Emphasis Type="Italic">Rhabdias lacertae</Emphasis> n. sp. (Nematoda: Rhabdiasidae), the first rhabdiasid species parasitising lizards in Europe

A new nematode species, Rhabdias lacertae n. sp. (Rhabdiasidae), is described from the body-cavity of the common lizard Lacerta vivipara Jacquin (Lacertidae) from the Ridge of Malá Fatra (Sokolie Hill), north-western Slovakia. The new species differs from its congeners mainly in possessing 3 min cuticular spikes at the tail tip and some other features. This is the first species of Rhabdias Stiles & Hassall, 1905 described from lizards in Europe and the first species of this genus parasitising hosts belonging to the Lacertidae.     

Habitat selection of an expanding beaver (Castor fiber) population in central and upper Morava River basin

Habitat selectivity by European beaver (Castor fiber L., 1758) was studied in 226 km of river channels during their colonization of the Morava River basin (the Czech Republic), which had not been occupied by beavers for hundreds of years. The colonization started after initial reintroductions in 1991 and 1992. Annual increases in colonization of the river system from 1995 to 2007 were 15.5 ± 9.4 SD km year⁻¹ and varied greatly between these years (min 0 km, max 33 km). Beavers appeared to be following a dispersal pattern, in which distant sites are often colonized before close-by sites. The selection of habitat variables during the colonization process varied. In the early phase of colonization, there were many areas with optimal habitat that were not occupied by beavers, and habitat selection appeared chaotic. After this early phase, the most significant habitat variable related to beaver occupation was shown to be the presence of willow (Salix spp.) species. In the later phases, the beaver population expanded into suboptimal habitat. Settlement distance from roads, railways, and urbanized areas became less. When comparing the generalized linear models, a model from the winter of 2003/2004 had the best overall accuracy and showed excellent agreement among observed and fitted values (Cohen’s κ = 0.75). The model suggests that beavers established their home ranges at first in optimal habitat, which had not been occupied before and then subsequently in suboptimal/marginal areas.     

Fragmented DNA and apoptotic bodies document the programmed way of cell death in hybridoma cultures

Markers of apoptosis were followed in batch hybridoma cultures carried out in protein-free medium. Samples were collected on day 0, representing early exponential phase (viability 91%), and on day 8, corresponding to late stationary phase (viability 8%). The apoptotic index reflecting the relative number of bodies insoluble in 6 M guanidinium hydrochloride in the culture of day 8 (30%) exceeded markedly the index in the culture of day 0 (2.5%). A gel chromatography on Sepharose 2B was developed for quantitative evaluation of fragmented cellular DNA. This analysis, including a correction for nonspecific fragmentation, showed that on day 8 more than 30% of cellular DNA was fragmented, whereas on day 0 it was less than 5%. Control necrotic cells prepared by rapid killing in 1% sodium azide displayed a low apoptotic index (2.4%) and low DNA fragmentation. Electrophoretic patterns in agarose gel showed a typical “ladder” of fragments in the DNA sample of day 8. The demonstration of fragmented cellular DNA and of the high incidence of apoptotic bodies at late stationary phase adds substantial weight to the view that in hybridoma cultures apoptosis represents the prevalent mode of cell death.