Volume 72, Issue 2

Allelopathy is an important ecological phenomenon influencing ecosystem dynamics. Currently, it has gained attention due to the potential applications of allelochemicals in agriculture. Allelopathic interactions have been reported in ecological relationships between plants and microorganisms, and between species of each group. These studies have been relatively descriptive, however, without interconnected views of how these molecules can affect cell biology and how they are integrated into environmental interactions. The present review provides an overview of the history, physiology, and ecological effects of allelopathy, with special focus on its occurrence between macro- and microorganisms and its ecological roles in terrestrial and aquatic environments. We have attempted to examine the interconnections between terrestrial and aquatic systems in relation to the production, dynamics, and ecological effects of allelochemicals and to discuss the possible effects of climate changes on allelopathic interactions.

Eighteen bacterial strains were isolated from soil of an urban area located in a transition zone between the Atlantic Forest and Pampa biomes, in southern Brazil. These strains were screened for cellulolytic, lipolytic and proteolytic potentials. Eleven isolates (61%) were able to produce cellulolytic enzymes on carboxymethylcellulose (CMC) agar plates, 14 isolates (78%) were proteolytic on skim milk agar plates, and all isolates demonstrated lipolytic/esterolytic potential on tributyrin agar (TBA) plates. From the 18 bacteria, nine (50%) were shown to produce the three investigated enzyme activities. Selected isolates were then evaluated for growth and enzyme production at different conditions of temperature and pH on CMC agar, TBA, and feather meal agar plates. As a general trend, growth and hydrolysis zones were observed at pH 6.0–9.0 and 30–37 ∘ C. Sequencing of 16S rRNA gene fragments indicated that 10 isolates belonged to the genus Bacillus, three to Lysinibacillus genus, and the remaining isolates were representatives of Serratia , Phyllobacterium , Paenibacillus , Acinetobacter , and Curtobacterium . The isolate Bacillus sp. CL18 displayed competence for feather degradation when cultured in mineral medium (30 ∘ C, pH 7.0) containing a single feather as the only organic substrate. Results from bioprospection indicate the functional versatility of the bacterial isolates, which might be of significance from both ecological and biotechnological perspectives.

A plasmid pCAMBIA1301 containing Pleurotus eryngii cellulase gene ( PEcbh ), under the control of Lentinus edodes glyceraldehyde-3-phosphate dehydrogenase ( LEgpd ) promoter, was constructed and used as an expression vector. The vector was transformed into the tissue of P. eryngii using Agrobacterium tumefaciens -mediated transformation (ATMT) method and 4 transformants (PET1-4) were obtained. The positive transformants were confirmed by cultivation in media containing hygromycin and by PCR amplification of hygromycin B resistance- LEgpd promoter gene fragment. Unpredicted, cellulase specific activities of the transformants were not higher than those of the wild type. Mushroom cultivation was performed in the laboratory and the results revealed that the average biological efficiency of PET4 was significantly 1.52 times higher than those of the wild type.

The effects of increasing concentrations of cadmium (Cd) on the ultrastructure, Cd accumulation, nutrient elements contents, levels of chlorophyll pigments, hydrogen peroxide (H 2 O 2 ), malondialdehyde (MDA), antioxidants, as well as the activities of antioxidant enzymes were investigated in the leaves of Hydrocharis dubia (Bl.) Backer. Cd exposure resulted in significant damage in chloroplasts and mitochondria, suggesting that Cd hastened the senescence of the tested plants. The accumulation of Cd was found to increase in a concentration dependent manner with a maximum of 1088 μg g −1 at 80 μM. The levels of Ca, P and Cu declined and the levels of Mg increased under all Cd concentrations, but K and Fe contents increased initially and decreased thereafter. Pigment content decreased with the rise of the Cd concentrations. H 2 O 2 content enhanced gradually at all Cd concentrations. MDA content increased progressively up to 60 μM Cd, followed by a decline at higher concentration. The effect of Cd application on ascorbate (AsA) and reduced glutathione (GSH) contents was similar to that seen for H 2 O 2 content. Peroxidase (POD) and catalase (CAT) activities first increased and then decreased, while superoxide dismutase (SOD) activity markedly decreased. Results suggest that Cd-induced oxidative damage in H. dubia is closely associated with the efficiency of its intrinsic antioxidant mechanisms, both the disorder of nutrient elements and the damage to the ultrastructure were indicative of general disarray in the cellular functions exerted by Cd.

Morphologically normal and fertile transgenic chickpea plants have been regenerated through a standardized transformation protocols. This protocol is based on the infection of apical meristem explants (AME) with Agrobacterium strain EHA105. The stain, carrying pCAMBIA2301 vector contained β -glucuronidase ( uid A) gene and neomycin phosphotransferase ( npt II) genes. Different explants of chickpea and Agrobacterium specific conditions were standardized with the help of transient β -glucuronidase ( uid A) gene expression to further optimize the transformation protocol. Pre-conditiong of the explants, vacuum infiltration and presence of acetosyringone significantly enhanced the frequency of gus expression. Positive transformants with npt II and gus genes were confirmed by PCR and histochemical gus analysis. An overall successful chickpea transformation frequency of 1.2 was achieved. This high efficiency and easy to use method may provide opportunities for the development of transgenic lines with different useful genes in chickpea in near future.

Solidago minuta L., a high-mountain species of the Solidago virgaurea group, occurs on some European mountain chains but it has been suggested that morphological differentiation of S . minuta is controversial due to the existence a wide range of morphologically intermediate plants between lowland S . virgaurea s . s . and high-mountain S. minuta . However, the recent study of this group revealed that both S . minuta and S. virgaurea are morphologically distinct taxa and that their most important taxonomical characters are those relating to the capitulum and florets. The aim of the present study is to verify the distribution of S . minuta in the Polish Carpathians and Sudetes and to identify the ecological characteristics of the species in relation to soil and vegetation. Solidago minuta was found most commonly in the Tatra Mts, but was also frequently encountered on Babia Góra Mt. and on the Karkonosze Mts. In the Tatra Mts, this species occurs most frequently in the subalpine belt, ascending in places to the alpine belt and descending in open areas to the upper montane belt. The preferred soils were acid, the pH mainly being between 3.5 and 5.0, and with relatively low nutrient content. Direct gradient analysis (CCA) revealed that the most important environmental variables explaining the general variability in species composition were altitude, as well as soil calcium content and soil acidity. S . minuta was found to occur mainly in communities of the Calamagrostietalia villosae order, growing amongst tall grass on lime-deficient substrata and grazed semi-natural vegetation, which here, in the subalpine belt, is widespread.

Peat bogs play key roles in preserving the stability of ecological relationships, but are some of the fastest disappearing and most endangered ecosystems in Europe. The aims of this study were: (1) to compare the distribution, species richness, diversity, and density of rotifers in microhabitats of a raised bog; and (2) to verify the hypothesis that rotifer density and species composition are dependent on seasonal factors, moss moisture content, and the dominant species of mosses in the microhabitats. Sampling was done monthly from April to November in 2013–2014 in the bog Moszne in eastern Poland (51°27′28.7″ N, 23°07′15.8″ E). The microhabitats sampled included hummocks, slopes, and hollows. A total of 40 rotifer taxa were identified. The highest species richness occurred in the hollows (40), dominated by Sphagnum angustifolium . Markedly lower numbers of taxa were observed on the slopes (28) dominated by Sphagnum magellanicum and Sphagnum rubellum , and in the hummocks dominated by S. magellanicum and Polytrichum sp. During the entire study period all the studied microhabitats were dominated by the Bdelloidea: Habrotrocha angusticollis , Habrotrocha lata , Habrotrocha sp., Dissotrocha macrostyla , Philodina sp. as well as Rotaria rotatoria and Rotaria tardigrada . The greatest species diversity of rotifers was recorded in the hollows (diversity index H′ = 2.307) and the smallest in the hummocks ( H′ = 0.769). The density of rotifers was also the highest in the hollows. Statistically significant differences in densities of rotifers between the microhabitats were found (Kruskal–Wallis test: H′ (2, n = 33)= 10.33, P = 0.005). The greatest diversity of rotifers and the greatest density were observed in spring.

Although harvestmen (Opiliones) are among the best studied groups of arachnids in Europe from the faunistic point of view, there is still lack of available information on ecological requirements of the particular species. Habitat preferences that determine the distribution of species are largely determined by the habitat structure and microclimate. Besides other factors, these characteristics of habitats are also influenced by the nature of the vegetation. Therefore, our study dealt with the influence of tree species on harvestmen communities. We conducted the research on nine sites in the Borová hora arboretum (Zvolen town, Central Slovakia). Each studied site represents a monoculture of one of nine tree species. On each site also some attributes of soil and leaf litter (pH, conductivity, content of H, C, N and P) were evaluated. Harvestmen were collected by pitfall trapping during vegetation periods in 2008–2012. In total, 2515 individuals of 17 species and 3 families were obtained. Significant differences were revealed between the compared forest stands in terms of total epigeic activity and species richness of harvestmen. The hierarchical cluster analysis divided harvestmen communities into two main clusters (except community of the site with European hornbeam). The first one represented four sites with relatively lower canopy (< 50%) and with the higher number of captured individuals, the second cluster grouped four sites with higher canopy (> 50%) and with the lower number of captured individuals. The results of research confirmed statistically significant relationships between the litter conductivity and equitability and between the litter pH and equitability of harvestmen communities.

A crossover design was used to study food preferences and capability of nutritional acclimation to different food sources in terrestrial isopods, which live in xeric environments, by using Armadillo officinalis as an experimental model. The foods chosen for this experiment were three fresh foods with different content of water (potato, carrot, lettuce), and a dry food (leaf of plane tree). In order to quantify these preferences, two kinds of data able to provide complementary information were collected: number of droppings produced and food ingested per week. These data were used to fit some mixed effects models, in order to highlight statistically significant differences among the foods provided to the animals at a level of preferences. In addition, the buccal appendages of A. officinalis were observed and drawn in details, to provide further information at this level. Our results showed that A. officinalis seems not to have particular preferences between fresh foods with a moderate quantity of water and dry food, commonly eaten in its natural habitat. In contrast, foods with high quantity of water, like the lettuce, seem not to be instead particularly palatable for its taste, or its nutritional needs. Also, this study seems to have highlighted a better capability of digestion and absorption of the potato tuber compared to the leaf of plane tree for an equal quantity of ingested food. Anyway, this hypothesis needs further insights in order to be able to be verified.

From 1997 until 2014 we carried out a GIS-based systematic mapping of mosquito breeding sites on a 2,690 km 2 area in the important touristic regions of Hungary. During the process of data collection of the mosquito fauna, 42,547 adults of 26 species and 34,409 larvae of 28 species were collected. The ecological characteristics of the breeding sites were recorded by means of 4,543 samples. We have specified 13,808 breeding sites playing important role in mosquito harm for the human population with an overall area of 7,967 hectares in topologically correct digital maps. We have established that approximately 1% of the administrative area of mosquito affected lands and 10% of wetlands can be considered as target areas for biological control taking human viewpoints into account. According to the results of our research, the most environment-friendly (affecting about 10% of the wetland areas routinely treated), economical and effective mosquito control can be carried out by BTI treatments based on GIS mappings.

Invasive plants are non-native, but in most cases naturalised, species that have successfully spread outside of their native range. Aliens invaded all habitats, are competing with native plants, thus, after the direct destruction of habitats, invasions are recognised as the second largest danger for biodiversity. Northern Red Oak is one of the most common invasive tree species dispersed primarily by birds, but new studies have shown that it is also spread continuously in a forest stand. The main aim of our research was to check how strong is the invasion of Northern Red Oak in Silesia Park, where it was introduced together with other alien plant species, and how this invasion interacts with bird diversity. Silesia Park was created 65 years ago on the surface largely ravaged by coal industry. Because many studies indicate birds as vectors of alien plants invasion, we examined the bird fauna in a described area, looking for species that can contribute to spreading oaks. Research showed the diversity of 50 bird species. Surface with a presence of Northern Red Oak was characterised by greater participation of alien plant species than the patch of natural forest, which existed there long before the park creation. The greatest bird diversity was found in the most natural part of Silesia Park, and the lowest in the area of invasion, especially in the case of species classified as “forest birds”. The presence of alien plants increased number of “non-forest” birds, mostly synanthropic species. We also found that Northern Red Oak spreads by spontaneous seed dispersal.

The study evaluated shape of the foramen magnum (FM) in dog with regard to its constitutional type (small, medium and large breeds) and morphotype (brachycephalic, mesaticephalic and dolichocephalic dogs). We used multi-slice CT scanner to examine occipital area of 138 purebreds dogs. Two studied groups could be distinguished – living animals undergoing standard diagnostic CT procedure ( n = 47) and macerated skulls of euthanized dogs ( n = 91). Morphometric analysis was focused on presence of dorsal notch within foramen magnum. This anatomical feature was present in 33.3% of examined dogs. It was more often observed in small size dogs (70%) and those of brachycephalic morphotype (94.1%). For the first time dorsal notch was noted in breeds such as French Bulldog, Fox Terrier, Keeshond, Standard Schnauzer, English Bulldog, Cocker Spaniel, Boxer and Rottweiler. We distinguished four different shape of FM: oval, pentagonal, rhomboid and circular. Most common FM shape was oval (41 dogs; 45%) whereas circular type was least observed (5 dogs; 5.5%). The pentagonal shape was noticed in 27 specimens (29.7%) and the rhomboid shape in 18 dogs (19.8%). Authors conclude that dorsal notch is not pathology and should be considered a morphological variation within the normal anatomy. Results presented in this study should be taken into account during interpretation of the CT images of the craniocervical junction.

Hypercholesterolemia has been considered as a risk factor for Alzheimer’s disease (AD). In addition to low density lipoprotein (LDL), oxidized LDL plays some roles in AD pathology. Neurodegenerative effect of oxidized LDL was supported by the increased oxidative stress in neurons. To further investigate the role of oxidized LDL, the present study aimed to test its effect on amyloid precursor protein (APP) processing. The release of soluble APP (sAPP) was evaluated in differentiated SH-SY5Y neuroblastoma cells exposed to native (non-oxidized) or oxidized human LDL including mildly and fully oxidized LDL (mox- and fox-LDL). Non-amyloidogenic and amyloidogenic pathways were investigated using specific antibody against sAPP α and sAPP β . The results demonstrate that oxidized LDL induced neuronal death in dose-dependent patterns. Mox-LDL mediated caspase-3 dependent apoptosis, whereas fox-LDL notably damaged cell membrane. At subtoxic concentration, only native but not oxidized LDL induced the release of sAPP dominantly in amyloidogenic pathway with no change in β -secretase activity. These results suggest that LDL and oxidized LDL play critical roles in AD pathogenesis via different pathways. Elevated serum LDL level together with high oxidative stress may aggravate the progression of AD.