Bathypelagic percid fry,a strongly predominating fry community in a deep European reservoir

The distribution, species composition, abundance and shoaling behaviour of young-of-year fish were studied in the canyon-shaped Vír Reservoir (Czech Republic) in mid-June 2010. Using the SIMRAD EK60 echosounder (frequency 120 kHz), fry were acoustically sampled along the longitudinal profile of the reservoir. A framed trawl was used simultaneously to collect fry in the open water. Apparent differences were found in the density of fry between the epipelagic, littoral and bathypelagic zones. Bathypelagic fry strongly predominated in the total fry community creating 95.3% while epipelagic and littoral fry contributed only 4.7%. The bathypelagic fry were represented by perch Perca fluviatilis (84.8%), zander Sander lucioperca (14.9%) and ruffe Gymnocephalus cernua (0.15%) and were observed all along the longitudinal profile of the reservoir creating a distinct layer on the echogram. The layer, composed of shoaling and non-shoaling fry individuals, reached its greatest depth in the Bay part of the reservoir (7.5–14.5 m) and it was rising in the water column towards the tributary. The situation that the bathypelagic percid fry predominate in the reservoir is absolutely unique and it is completely different from published observations from other canyon-shaped reservoirs where epipelagic percid fry prevailed.

     

The cardiac ryanodine receptor: Looking for anomalies in permeation properties

Anomalies in the permeation properties of the cardiac RyR channel reconstituted into bilayer lipid membranes were investigated systematically. We tested the presence of the anomalous mole fraction effect (AMFE) for the ion conductance and the reversal potential with varying mole fractions of two permeant ions, while the total ion concentration was lower, as in previous studies, to avoid the masking effect of the channel pore saturation with ions. Mixtures of Ba²⁺ with other divalents (Ca²⁺, Sr²⁺), of Ca²⁺ with monovalents (Li⁺, Cs⁺), and of Na⁺ with other monovalents (Cs⁺, Li⁺) were used. We revealed a clear anomaly only for the ion conductance measured in the Na⁺-Cs⁺ and Ca²⁺-Li⁺ mixtures as computed by a Poisson-Nernst-Planck/density functional theory (PNP/DFT) model. Furthermore, we found a significant minimum in the concentration dependence of the reversal potential determined under Li⁺/Ca²⁺ bi-ionic conditions. Our study led to new observations that may have important implications for understanding the mechanisms involved in ion handling in the RyR channel pore; furthermore our results could be useful for further validation of ion permeation models developed for the RyR channel.     

Doubled haploid production in Flax (Linum usitatissimum L.)

There is a requirement of haploid and double haploid material and homozygous lines for cell culture studies and breeding in flax. Anther culture is currently the most successful method producing doubled haploid lines in flax. Recently, ovary culture was also described as a good source of doubled haploids. In this review we focus on tissue and plants regeneration using anther culture, and cultivation of ovaries containing unfertilized ovules. The effect of genotype, physiological status of donor plants, donor material pre-treatment and cultivation conditions for flax anthers and ovaries is discussed here. The process of plant regeneration from anther and ovary derived calli is also in the focus of this review. Attention is paid to the ploidy level of regenerated tissue and to the use of molecular markers for determining of gametic origin of flax plants derived from anther and ovary cultures. Finally, some future prospects on the use of doubled haploids in flax biotechnology are outlined here.     

The effects of plant traits on species' responses to present and historical patch configurations and patch age

Patch configuration is viewed as an important factor affecting the distributions of plant species. Although a number of studies have explored the relationship between plant life‐history traits and species’ distributions in fragmented landscapes, the effect of individual traits on the dependence of species on historical versus current landscape configurations remains unclear. We identified the extent to which present (2000s) and historical (1843, 1954, 1980s) patch configurations (area and connectivity) and patch age affected the distributions of 99 species inhabiting dry calcareous grasslands. We used traits related to dispersal, survival, growth and habitat preferences to explain the dependence of 60 of these species on present and historical configurations, and the age of grassland patches. We found that most of the species had an affinity to currently or historically large, older and more isolated patches. This suggests that many dry grassland species are not in equilibrium with the current landscape, as their distributions still reflect past landscape structures. Rapidly growing species with higher seed bank longevity and nutrient requirements primarily occur in young, large grassland patches whereas species with the opposite traits occur in older, historically large and currently more isolated smaller patches. We hypothesise that patch quality is the reason why different species occupy patches of different age. Species occupying young, large patches commonly disperse by endozoochory. By contrast, no dispersal trait is associated with species occupying old, usually isolated patches. Our results suggest that species occupying old patches are exposed to higher potential risk of extinction, as their distributions are probably limited by the low number and connectivity of available suitable patches and poor dispersal ability. We thus suggest that the dynamics of these species can effectively be supported by improving the quality of young grassland patches.     

Cooccurring Gentiana verna and Gentiana acaulis and Their Neighboring Plants in Two Swiss Upper Montane Meadows Harbor Distinct Arbuscular Mycorrhizal Fungal Communities

The community composition of arbuscular mycorrhizal fungi (AMF) was analyzed in roots of Gentiana verna, Gentiana acaulis, and accompanying plant species from two species-rich Swiss alpine meadows located in the same area. The aim of the study was to elucidate the impact of host preference or host specificity on the AMF community in the roots. The roots were analyzed by nested PCR, restriction fragment length polymorphism screening, and sequencing of ribosomal DNA small-subunit and internal transcribed spacer regions. The AMF sequences were analyzed phylogenetically and used to define monophyletic sequence types. The AMF community composition was strongly influenced by the host plant species, but compositions did not significantly differ between the two sites. Detailed analyses of the two cooccurring gentian species G. verna and G. acaulis, as well as of neighboring Trifolium spp., revealed that their AMF communities differed significantly. All three host plant taxa harbored AMF communities comprising multiple phylotypes from different fungal lineages. A frequent fungal phylotype from Glomus group B was almost exclusively found in Trifolium spp., suggesting some degree of host preference for this fungus in this habitat. In conclusion, the results indicate that within a relatively small area with similar soil and climatic conditions, the host plant species can have a major influence on the AMF communities within the roots. No evidence was found for a narrowing of the mycosymbiont spectrum in the two green gentians, in contrast to previous findings with their achlorophyllous relatives.     

Acridine derivatives inhibit lysozyme aggregation

We have screened a library of structurally distinct acridine derivatives (19 compounds) for their ability to inhibit lysozyme amyloid aggregation in vitro. Studied acridines were divided into three structurally different groups depending on the molecule planarity and type of the side chain-planar acridines, spiroacridines and tetrahydroacridines. Thioflavine T fluorescence assay and transmission electron microscopy were used for monitoring the inhibiting activity of acridines. We have found that both the structure of the acridine side chains and molecule planarity influence their antiamyloidogenic activity. The planar acridines inhibited lysozyme aggregation effectively. Spiroacridines and tetrahydroacridines had no significant effect on the prevention of lysozyme fibrillization, probably resulting from the presence of the heterocyclic 5-membered ring and non-planarity of molecule. Moreover, in the presence of some tetrahydroacridines the enhanced extent of aggregation was detected. We identified the most active acridine derivates from studied compound library characterized by low micromolar IC(50) values, which indicate their possible application for therapeutic purpose.     

Suppressive potential of bean (Phaseolus vulgaris) flour against five species of stored-product mites (Acari: Acarididae)

Previous research has demonstrated that legume proteins have insecticidal activity against stored-product pests, but activity against stored-product mites has not been tested. A study was therefore conducted to explore the potential of bean, Phaseolus vulgaris L., flour as novel botanical acaricide against five species of storage and dust mites: Acarus siro L., Aleuroglyphus ovatus (Troupeau), Caloglyphus redickorzevi (Zachvatkin), Lepidoglyphus destructor (Schrank), and Tyrophagus putrescentiae (Schrank). The effect of wheat, Triticum aestivum L., grain enriched with bean flour to eight concentrations (0, 0.01, 0.1, 0.5, 1, 2.5, 5, and 10%) on population growth initiating from the density of 50 mites per 100 g of wheat was recorded for 21 d under laboratory conditions (grain moisture 14.6% moisture content and 25 degree C in darkness). The enrichment of grain with bean flour suppressed the population growth of all tested species: 0.01% concentration reduced population growth of all tested species to >50% in comparison with the control population. The most sensitive species were A. siro and L. destructor, followed by T. putrescentiae and C. redickorzevi. The least sensitive species was A. ovatus. The terminal (i.e., after 21 d) density of mites positively correlated with bean flour concentration. The suppressive effect of bean flour was not linear but rather asymptotic. The results of this study are discussed in the context of the application of bean flour in integrated control of stored-product mites and the elimination of stored-product mite allergens.     

A new modification of anti-tubercular active molecules

The connection of two active molecules across an easily released bridge as a new type of potentially active molecule has been studied. The synthesis is based on derivatives that originate from isonicotinoyl hydrazide, pyrazinamide, p-aminosalicylic acid (PAS), ethambutol, and ciprofloxacin. The lipophilicity, hydrolysis (stability of the compounds), and antituberculotic activity as well as the structure-lipophilicity and structure-activity relationships are discussed.