Growth and fecundity of Daphnia after diapause and their impact on the development of a population

Laboratory and field investigations revealed that the life history traits of exephippial and parthenogenetic generations of Daphnia differ substantially. Daphniids hatching from resting eggs grow faster and their definitive body sizes are bigger than of hatchlings from subitaneous eggs. Size at maturity for exephippial animals is significantly larger. In spite of this, they mature a few days earlier than parthenogenetic females. In this study, the difference was 3–4 days for the laboratory experiments and 1–3 days for the field. Fecundity of the exephippial generation is markedly higher. Here, the clutch size for this generation was up to 3.5–4.0 times as large as for the parthenogenetic generation. Moreover, obtained results suggest that the relationship between clutch size and body length for both generations differ significantly.Estimates of the intrinsic rate of increase for field Daphnia populations demonstrated that life history traits of exephippial animals lead to a two or threefold higher rate of increase in the conditions of invertebrate predation pressure. Under moderate fish pressure, obtained r values for the daphniids hatching from resting eggs were larger than those from subitaneous. High growth rate of exephippial females is disadvantageous only under the conditions of severe pressure by fish. Obtained results suggest that hatchlings from diapausing eggs an acceleration of population increase by several times during the beginning of the development of a population with periodical re-establishment from resting eggs.     

Low haemosporidian diversity and one key-host species in a bird malaria community on a mid-Atlantic island (São Miguel, Azores)

When host species colonize new areas, the parasite assemblage infecting the hosts might change, with some parasite species being lost and others newly acquired. These changes would likely lead to novel selective forces on both host and its parasites. We investigated the avian blood parasites in the passerine bird community on the mid-Atlantic island of S?o Miguel, Azores, a bird community originating from continental Europe. The presence of haemosporidian blood parasites belonging to the genera Haemoproteus, Plasmodium, and Leucocytozoon was assessed using polymerase chain reaction. We found two Plasmodium lineages and two Leucocytozoon lineages in 11 bird species (84% of all breeding passerine species) on the island. These lineages were unevenly distributed across bird species. The Eurasian Blackbird (Turdus merula) was the key-host species (total parasite prevalence of 57%), harboring the main proportion of parasite infections. Except for Eurasian Blackbirds, all bird species had significantly lower prevalence and parasite diversity compared to their continental populations. We propose that in evolutionary novel bird communities, single species may act as key hosts by harboring the main part of the parasite fauna from which parasites "leak" into the other species. This would create very different host-parasite associations in areas recently colonized by hosts as compared to in their source populations.     

On the after‐use and restoration of abandoned extracted peatlands in the Baltic countries

In the Baltic countries (Estonia, Latvia, and Lithuania), mires directly affected by peat extraction cover almost 90,000 ha. Of these, over 26,200 ha have already been extracted and are abandoned. The main aim of this article is to give an overview of the extent of extracted peatlands in the Baltics, the legislative background around the land‐use options, and the directions of after‐use of peatlands since the middle of the 20th century. We also critically review results from restoration of abandoned extracted peatlands and assess whether they are on a trajectory toward reinitiation of paludification and functioning mire ecosystems. Almost all currently existing abandoned extracted peatlands in the Baltics were abandoned during and shortly after the Soviet period (1940–1991) without any restoration measures. The rest of the extracted areas were mostly afforested, converted into agricultural lands, berry plantations, or water bodies. The after‐use was mostly experimental, lacking systematic, proper assessment of outcome, cost and benefits, and side effects. The data are scarce but it could be estimated that only <10% (Estonia and Lithuania) and <20% (Latvia) of the total area of abandoned extracted peatlands were used for some purposes after peat extraction. Recently, several trials aimed at restoring the mire vegetation and ecosystem functions have been started in abandoned extracted peatlands in all three countries. In the coming years, the restoration of extracted peatlands in the Baltics will start on much bigger areas within different projects and initiatives cofinanced by the European Union.     

Chemical composition and chemometric analysis of essential oils variation of <Emphasis Type="Italic">Bidens tripartita</Emphasis> L<Emphasis Type="Italic">.</Emphasis> during vegetation stages

The variation in the content and composition of essential oils of Bidens tripartita L. grown in Lithuania has been studied using supercritical CO₂ extraction followed by GC–MS. Extraction of essential oils was performed at two different pressures (9.1 and 15.1 MPa). Plant material has been harvested at different phenological stages (from June to September). A total of 26 different compounds were identified in the essential oils. The highest content and diversity of compounds was determined during the full-flowering stage. Identified substances were mainly monoterpene hydrocarbons and sesquiterpene hydrocarbons. The main components were α-pinene, p-cymene, trans-β-ocimene, and β-elemene. Chemometric analysis, including principal component and hierarchical cluster analyses, showed the dependence of the essential oils qualitative as well as quantitative composition on the phenological stage the plant was collected at. It also revealed that there was no correlation between age of the plant and quantity of the identified compounds.     

Mitochondrial reactive oxygen species generation triggers inflammatory response and tissue injury associated with hepatic ischemia-reperfusion: Therapeutic potential of mitochondrially targeted antioxidants

Mitochondrial reactive oxygen species generation has been implicated in the pathophysiology of ischemia-reperfusion (I/R) injury; however, its exact role and its spatial-temporal relationship with inflammation are elusive. Herein we explore the spatial-temporal relationship of oxidative/nitrative stress and inflammatory response during the course of hepatic I/R and the possible therapeutic potential of mitochondrial-targeted antioxidants, using a mouse model of segmental hepatic ischemia-reperfusion injury. Hepatic I/R was characterized by early (at 2h of reperfusion) mitochondrial injury, decreased complex I activity, increased oxidant generation in the liver or liver mitochondria, and profound hepatocellular injury/dysfunction with acute proinflammatory response (TNF-α, MIP-1α/CCL3, MIP-2/CXCL2) without inflammatory cell infiltration, followed by marked neutrophil infiltration and a more pronounced secondary wave of oxidative/nitrative stress in the liver (starting from 6h of reperfusion and peaking at 24h). Mitochondrially targeted antioxidants, MitoQ or Mito-CP, dose-dependently attenuated I/R-induced liver dysfunction, the early and delayed oxidative and nitrative stress response (HNE/carbonyl adducts, malondialdehyde, 8-OHdG, and 3-nitrotyrosine formation), and mitochondrial and histopathological injury/dysfunction, as well as delayed inflammatory cell infiltration and cell death. Mitochondrially generated oxidants play a central role in triggering the deleterious cascade of events associated with hepatic I/R, which may be targeted by novel antioxidants for therapeutic advantage.     

Formic Acid and Acetic Acid Induce a Programmed Cell Death in Pathogenic Candida Species

Cutaneous fungal infections are common and widespread. Antifungal agents used for the treatment of these infections often have undesirable side effects. Furthermore, increased resistance of the microorganisms to the antifungal drugs becomes the growing problem. Accordingly, the search for natural antifungal compounds continues to receive attention. Apoptosis is highly regulated programmed cell death. During yeast cell apoptosis, amino acids and peptides are released and can stimulate regeneration of human epithelium cells. Thus, detection of chemical compounds inducing apoptosis in yeast and nontoxic for humans is of great medical relevance. The aim of this study was to detect chemical compound inducing apoptosis in pathogenic Candida species with the lowest toxicity to the mammalian cells. Five chemical compounds—acetic acid, sodium bicarbonate, potassium carbonate, lithium acetate, and formic acid—were tested for evaluation of antifungal activity on C. albicans, C. guilliermondii, and C. lusitaniae. The results showed that acetic acid and formic acid at the lowest concentrations induced yeast cells death. Apoptosis analysis revealed that cells death was accompanied by activation of caspase. Minimal inhibitory concentrations of potassium carbonate and sodium bicarbonate induced Candida cells necrosis. Toxicity test with mammalian cell cultures showed that formic acid has the lowest effect on the growth of Jurkat and NIH 3T3 cells. In conclusion, our results show that a low concentration of formic acid induces apoptosis-like programmed cell death in the Candida yeast and has a minimal effect on the survivability of mammalian cells, suggesting potential applications in the treatment of these infections.     

Living in wetlands in the southeastern Baltic region during the Late Bronze to early Iron Age: the archaeological context of the Luokesa lake settlements

The prehistoric lake settlement tradition is spread far beyond the region of the Alps, and it has been known for a long time that lake settlements are not a characteristic of one particular area. The present paper presents the results of the first comprehensive, interdisciplinary investigations of such types of sites in Lithuania, the two lake settlements at Lake Luokesa (Luokesai e?eras). They were excavated with underwater archaeology techniques between 2000 and 2011. They are Late Bronze to early Iron Age transition (LBA–EIA) in date and were probably built and inhabited during a short period between 625 and 535 cal bc. The excavated archaeological material contains a wealth of well-preserved wooden architectural details and other organic materials. Therefore, the importance and unique character of these sites is beyond question. This paper gives an overview of the history of research on lake settlements in northeastern Europe. In addition, the archaeological material of the LBA–EIA settlements at Lake Luokesa is evaluated in the context of the other lake settlements in the southeastern Baltic region. Existing hypotheses and interpretations of the origins, development and use of the lake settlements of this region are discussed. All the investigations which have been done, including archaeobotany, palynology, dendrochronology and geoarchaeology, provide data for a well-grounded interpretation and reconstruction of the Luokesa lake settlements.     

Realization of the project for Acipenser oxyrhynchus oxyrhynchus restoration in the basin of the Neman River

The results of the works on the international project for the Baltic sturgeon restoration in the basin of the Neman River are considered. The mutual goal of the project is the restoration of the Baltic sturgeon population in its whole former area in the Baltic Sea. Successful works on the restoration of the Baltic sturgeon population are conducted in the Oder and the Vistula basins. The stockings of the Neman River with the sturgeon fry were started from 2012 year. It is contemplated that the sturgeon stockings of the main rivers of the Baltic Sea will enable to restore local sturgeon populations in these river basins. Till the beginning of the XXI century it was supposed that the Atlantic sturgeon Acipenser sturio had inhabited the Baltic Sea, but numerous genetic analysis of the samples of the sturgeon bones from the archeological finds in the museums showed that the Baltic Sea had been inhabited with Acipenser oxyrhynchus and its population still inhabits several rivers in Canada. This discovery permitted to start the creation of the Baltic sturgeon broodstock. Sturgeon fry from the eggs imported from Canada were used for stocking at the first stage of the project. Later it is contemplated to use the fry from the broodstocks in Germany and Poland. Sturgeon fry hatched from Canadian eggs in Poland and reared in Lithuania was used for the Neman River stocking. The fry were tagged and released in the Neris and the Sventoji Rivers in the Neman River basin. The sturgeon migrated into the Curonian lagoon where the monitoring of the catches was fulfilled. The results of sturgeon catches monitoring are discussed.