Effects of 5-HT1B receptor ligands microinjected into the accumbal shell or core on the cocaine-induced locomotor hyperactivity in rats.

The present study was designed to examine the effect of 5-HT1B receptor ligands microinjected into the subregions of the nucleus accumbens (the shell and the core) on the locomotor hyperactivity induced by cocaine in rats. Male Wistar rats were implanted bilaterally with cannulae into the accumbens shell or core, and then were locally injected with GR 55562 (an antagonist of 5-HT1B receptors) or CP 93129 (an agonist of 5-HT1B receptors). Given alone to any accumbal subregion, GR 55562 (0.1-10 microg/side) or CP 93129 (0.1-10 microg/side) did not change basal locomotor activity. Systemic cocaine (10 mg/kg) significantly increased the locomotor activity of rats. GR 55562 (0.1-10 microg/side), administered intra-accumbens shell prior to cocaine, dose-dependently attenuated the psychostimulant-induced locomotor hyperactivity. Such attenuation was not found in animals which had been injected with GR 55562 into the accumbens core. When injected into the accumbens shell (but not the core) before cocaine, CP 93129 (0.1-10 microg/side) enhanced the locomotor response to cocaine; the maximum effect being observed after 10 microg/side of the agonist. The later enhancement was attenuated after intra-accumbens shell treatment with GR 55562 (1 microg/side). Our findings indicate that cocaine induced hyperlocomotion is modified by 5-HT1B receptor ligands microinjected into the accumbens shell, but not core, this modification consisting in inhibitory and facilitatory effects of the 5-HT1B receptor antagonist (GR 55562) and agonist (CP 93129), respectively. In other words, the present results suggest that the accumbal shell 5-HT1B receptors play a permissive role in the behavioural response to the psychostimulant.     

Bioluminescence determination of enzyme activity of firefly luciferase in the presence of pesticides.

Firefly luciferase (EC 1.13.12.5) (FL) is the key enzyme in the firefly bioluminescence method (FB), which is widely used to determine the viability of living cells. The FB method can also be applied to monitoring the influence of different pollutants, such as pesticides. Firefly luciferase is a hydrophobic enzyme and its activity depends on the type of solvent, pH and substances present in the reaction mixture. The influence of three aromatic pesticides, including fenoxaprop-p-ethyl (I), diclofop-methyl (II) and metsulfuron methyl (III), on the enzyme activity was indirectly evaluated through the measurement of emitted light in the bioluminescence reaction, expressed in relative luminescence units (RLU). The reaction mixture used in the bioluminescence measurements consisted of: Tris buffer (pH 7.75), adenosine triphosphate (ATP) and ATP monitoring reagent, where FL is present. Ethanol-water solutions of each pesticide were then added at concentrations of 2.4 x 10(-4)-2.4 x 10(-8) mol/L. The FL activity inhibition factors (FL In%) were determined. The FL activity was maximally inhibited in the presence of all pesticides under study at a concentration of 2.4 x 10(-4) mol/L and was lowered by about 15-26% for pesticide I at concentrations of 2.4 x 10(-5)-2.4 x 10(-8) mol/L, whereas pesticides II and III, applied in the same concentration range, showed smaller FL inhibition values (5.3-20%). The pesticide degradation products (obtained after a 1 month period), measured in the same experimental conditions, in most cases exhibited a much less inhibitory effect on the enzyme activity than the corresponding initial pesticide.     

Clay minerals as a factor influencing the biochemical activity of soil microorganisms

The results of the study confirm the significance of clay minerals as a factor influencing the biochemical activity of soil microorganisms. The soil microflora is influenced both by the direct effect of clays on the microbial cells and indirectly, by their effect on the environment. The direct effect is projected into fundamental processes of the cycle of biogenic elements, including humification processes. The character and mechanism of the effect depend on the species of microorganism, on the quality and quantity of the mineral sorbents present in the soil and on other ecological factors. A further study will be carried out to investigate different aspects of the influence of clay minerals on the incidence, growth and biochemical activity of soil microorganisms.     

Impact of windstorm on a community of centipedes (Chilopoda) in a beech forest in Western Poland

The study was carried out in the years 2016–2017, five years after a windstorm which destroyed 1/3 of the protected beech forest area in the west of Poland. The community of centipedes in the area affected by the windstorm was depleted in terms of the species richness, diversity, and population density. The dominance structures were shortened and the species composition was rebuilt. The areas that proved to be the richest in terms of species richness and diversity among the sites affected by the windstorm were the one where windfallen trees were left and the other where beech trees had been planted by humans. In total, the quantitative and qualitative samples collected four times throughout a year featured 608 specimens from 11 species of two centipede orders – Lithobiomorpha and Geophilomorpha. Lithobius curtipes and L. forficatus were found in all of the investigated areas. L. pelidnus and L. piceus were captured at control sites exclusively. Only one species –L. erythrocephalus was found solely at the damaged site. The most numerous and most frequently found species in the community were L. curtipes, L. mutabilis, and Strigamia acuminata respectively. Although windstorms are natural phenomena their consequences may lead to significant changes in the community of the investigated soil animals. The importance of coarse woody debris, significantly contributing to the improvement and maintenance of species richness and diversity of Chilopoda, has once again been confirmed.     

Niche shifts and range expansions along cordilleras drove diversification in a high‐elevation endemic plant genus in the tropical Andes

The tropical Andes represent one of the world's biodiversity hot spots, but the evolutionary drivers generating their striking species diversity still remain poorly understood. In the treeless high‐elevation Andean environments, Pleistocene glacial oscillations and niche differentiation are frequently hypothesized diversification mechanisms; however, sufficiently densely sampled population genetic data supporting this are still lacking. Here, we reconstruct the evolutionary history of Loricaria (Asteraceae), a plant genus endemic to the Andean treeless alpine zone, based on comprehensive population‐level sampling of 289 individuals from 67 populations across the entire distribution ranges of its northern Andean species. Partly incongruent AFLP and plastid DNA markers reveal that the distinct genetic structure was shaped by a complex interplay of biogeography (spread along and across the cordilleras), history (Pleistocene glacial oscillations) and local ecological conditions. While plastid variation documents an early split or colonization of the northern Andes by at least two lineages, one of which further diversified, a major split in the AFLP data correlate with altitudinal ecological differentiation. This suggests that niche shifts may be important drivers of Andean diversification not only in forest–alpine transitions, but also within the treeless alpine zone itself. The patterns of genetic differentiation at the intraspecific level reject the hypothesized separation in spatially isolated cordilleras and instead suggest extensive gene flow among populations from distinct mountain chains. Our study highlights that leveraging highly variable markers against extensive population‐level sampling is a promising approach to address mechanisms of rapid species diversifications.     

Effects of post-translational modifications on prion protein aggregation and the propagation of scrapie-like characteristics in vitro

Prion diseases, or transmissible spongiform encephalopathies (TSEs) are typically characterised by CNS accumulation of PrP(Sc), an aberrant conformer of a normal cellular protein PrP(C). It is thought PrP(Sc) is itself infectious and the causative agent of such diseases. To date, no chemical modifications of PrP(Sc), or a sub-population thereof, have been reported. In this study we have investigated whether chemical modification of amino acids within PrP might cause this protein to exhibit aberrant properties and whether these properties can be propagated onto unmodified prion protein. Of particular interest were post-translational modifications resulting from physiological conditions shown to be associated with TSE disease. Here we report that in vitro exposure of recombinant PrP to conditions that imitate the end effects of oxidative/nitrative stress in TSE-infected mouse brains cause the protein to adopt many of the physical characteristics of PrP(Sc). Most interestingly, these properties could be propagated onto unmodified PrP protein when the modified protein was used as a template. These data suggest that post-translational modifications of PrP might contribute to the initiation and/or propagation of prion protein-associated plaques in vivo during prion disease, thereby high-lighting novel biochemical pathways as possible therapeutic targets for these conditions.     

metaGEM: reconstruction of genome scale metabolic models directly from metagenomes

Metagenomic analyses of microbial communities have revealed a large degree of interspecies and intraspecies genetic diversity through the reconstruction of metagenome assembled genomes (MAGs). Yet, metabolic modeling efforts mainly rely on reference genomes as the starting point for reconstruction and simulation of genome scale metabolic models (GEMs), neglecting the immense intra- and inter-species diversity present in microbial communities. Here, we present metaGEM (https://github.com/franciscozorrilla/metaGEM), an end-to-end pipeline enabling metabolic modeling of multi-species communities directly from metagenomes. The pipeline automates all steps from the extraction of context-specific prokaryotic GEMs from MAGs to community level flux balance analysis (FBA) simulations. To demonstrate the capabilities of metaGEM, we analyzed 483 samples spanning lab culture, human gut, plant-associated, soil, and ocean metagenomes, reconstructing over 14,000 GEMs. We show that GEMs reconstructed from metagenomes have fully represented metabolism comparable to isolated genomes. We demonstrate that metagenomic GEMs capture intraspecies metabolic diversity and identify potential differences in the progression of type 2 diabetes at the level of gut bacterial metabolic exchanges. Overall, metaGEM enables FBA-ready metabolic model reconstruction directly from metagenomes, provides a resource of metabolic models, and showcases community-level modeling of microbiomes associated with disease conditions allowing generation of mechanistic hypotheses.     

Effectiveness of mowing for the flora diversity preservation: a case study of steppe-like grassland in Croatia (NATURA 2000 site)

Intensive human activities have resulted in a critical reduction of grasslands in Croatia, one of the richest Europian countries in terms of biodiversity. Sub-Pannonic steppic grasslands are very rare, only few occur in the continental part of Croatia and most of them are protected as NATURA 2000 sites. We studied vascular flora of the Sub-Pannonic stepic grassland with the aim to examine the changes in plant communities 15 years from the mowing application. Results showed that hand mowing once per year at the end of vegetation season increased the species diversity as well as the number of medium and low growth taxa. The critically endangered, nearly threatened and vulnerable species remained preserved. The occurrence of trees, shrubs and invasive species as a consequence of succession and anthropogenic influences could be important threat for steppe-like grassland flora. From a conservation point of view infrequent mowing regime could be an effective management tool, although it needs to be adapted to regional and local circumstances for maintaining high biodiversity of steppe-like grasslands and valuable plant species.