Differential activation of JNK in rat hippocampus following acute and/or chronic stressors.

c-Jun N-terminal kinase (JNK) is activated by phosporylation in response to cellular stressors and extracellular signals and plays a role in the activation of glucocorticoid receptor (GR) and contributes to the stress-induced apoptosis. Therefore, the expression protein pattern of the active forms of cytosolic phospho- JNK (P-JNK) and inactive JNK in hippocampus of rats exposed to 21daily isolation as chronic stressor, sole and in combination with 2hrs acute stressors of immobilization (IM) or cold (4oC), were followed by Western blot. Concentration of serum corticosterone was monitored. We found significant increase in the levels of P-JNK following acute IM. Decreased levels of P-JNK following chronic isolation and when isolation preceded the application of acute IM were found, compared to its level after acute IM. Data suggest that diminished expresion of PJNK level following chronic isolation in hippocampus, might be involved in deregulation of intracellular GR negative feedback control as well as stress-induced apoptosis.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Orno-Cotino-Quercetum Pubescentis Ass. nova prov. on the slopes of Titel hill (Serbia)

Studied by many botanists from the floristic and vegetation-geographical aspects over the last hundred years, the herbaceous plant cover in dominant on Titel Hill. The first data on plant communities were registered in 1983, when a significant contribution to the study of vegetation of steppe character was made. At that time, presence of shrubby remnants of forest vegetation on Titel Hill was registered. Since 1983, fragments of typical xerothermic woods of pubescent oak have been registered

Comparative analyses of the vascular flora of the Pčinja river gorges in Serbia and Macedonia

The study’s aim is the comparative chorologic and ecological analysis of the vascular flora of the two gorges of the Pčinja River in Serbia and Macedonia which are 27 km apart. In the two gorges 1564 taxa have been recorded, 1057 being in the upper gorge in Serbia and 1174 in the lower gorge in Macedonia. Common to both gorges are 666 taxa. Chorological spectra show that in both gorges the most abundant are Mediterranean-submediterranean plants, 32.85% being in the upper and 43.97% in the lower gorge. Differences in the studied vegetation result from a diverse participation of other floristic elements such as Central European ones that are more abundant in the upper gorge (17.05%) than in the lower gorge (10.86 %). The life-form spectrum reveals that the flora in both gorges is hemicryptophyte-therophyte in character. Both gorges belong to an enclave of a Mediterranean-submediterranean region, i.e. to its submediterranean Macedonian- Thracian province

Stress-induced alternations of CuZn- and Mn- superoxide dismutase activity in rat liver

Superoxide dismutases (SODs) represent the first line of antioxidant defense and any alternation in their function might be potentially damaging. Therefore, changes of the CuZnSOD activity in cytosolic and nuclear fractions and MnSOD activity in mitochondrial fraction in liver of male rats exposed to 2h of either immobilization (IM) or cold (4°) as acute stressors, 21 day of social isolation (IS) as chronic stress, or their combination (acute+chronic stress), were investigated. Serum corticosterone (CORT) level was monitored as a stress marker. Acute stress IM with elevated CORT level led to increased CuZnSOD activity in nuclear fraction. Chronic isolation, where CORT was close to control value did not change the CuZnSOD activity neither in nuclei nor cytosol fraction, while combined stress IS+Cold led to increased cytosolic CuZnSOD activity. MnSOD activity in mitochondrial fraction was decreased in all treated groups. Data indicate that unchanged or increased cytosolic or nuclear CuZnSOD activity after different stressors mediate liver restoration of homeostasis, while decrease of mitochondrial MnSOD activity may results in cellular injury and inefficient ROS defense

The isovalerate and 2-methylbutanoate of artemisia alcohol–new compounds from Artemisia annua L. essential oil

Artemisia annua L. (sweet wormwood) is an essential oil (EO)-rich, medicinally valuable plant species from the Asteraceae family [1]. During the analysis of the biologically active A. annua EO sample (hydrodistilled from the dry aboveground parts of the plants; oil yield 0.2%, w/w; the main components (relative abundance): artemisia ketone (35.7%), a-pinene (16.7%), 1,8-cineole (5.5%), artemisyl alcohol (4.8%), and trans-pinocarveol (4.8%) [1]), we have detected two minor compounds, AA1 and AA2 (0.06% and less than 0.05% of the total oil, with RI (DB5-MS) values of 1367 and 1373, respectively) with practically identical mass spectral (MS) fragmentation patterns (EI, 70 eV; m/z (rel. int.)): 169(15), 85(100), 57(38), 41(17). The comparison of GC (≈300 unit higher RI values) and MS data of AA1 and AA2 with those of artemisyl acetate (often present in EOs containing artemisia ketone and artemisia alcohol) suggested these might be esters of artemisia alcohol and (isomers of) pentanoic acids. To confirm this tentative identification, and possibly detect some additional AA1 and AA2 homologs, we prepared esters of artemisia alcohol and valeric, isovaleric, 2-methylbutanoic, butanoic, isobutanoic and propanoic acids (Steglich esterification; the starting alcohol was obtained by LiAlH4 reduction of artemisia ketone isolated from the EO). Co-injection of the EO sample with synthetic standards confirmed AA1 and AA2 were artemisyl isovalerate and artemisyl 2-methylbutanoate (diastereomer not determined), respectively (Fig. 1). Detailed re-analysis of the EO revealed the presence of initially undetected trace amounts of artemisyl acetate. The results of this work once again confirm the importance of natural product-inspired libraries of synthetic compounds in the analysis of EOs, especially when it comes to the detection and identification of trace constituents

Inference of Convergent Gene Acquisition Among Pseudomonas syringae Strains Isolated From Watermelon, Cantaloupe, and Squash

Pseudomonas syringae sensu strict , (phylogroup 2; referred to as P. syringae) consists of an environmentally ubiquitous bacterial population associated with diseases of numerous plant species. Recent studies using multilocus sequence analysis have indicated the clonal expansion of several P. syringae lineages, located in phylogroups 2a and 2b, in association with outbreaks of bacterial spot disease of watermelon, cantaloupe, and squash in the United States. To investigate the evolutionary processes that led to the emergence of these epidemic lineages, we sequenced the genomes of six P. syringae strains that were isolated from cucurbits grown in the United States, Europe, and China over a period of more than a decade, as well as eight strains that were isolated from watermelon and squash grown in six different Florida counties during the 2013 and 2014 seasons. These data were subjected to comparative analyses along with 42 previously sequenced genomes of P. syringae stains collected from diverse plant species and environments available from GenBank. Maximum likelihood reconstruction of the P. syringae core genome revealed the presence of a hybrid phylogenetic group, comprised of cucurbit strains collected in Florida, Italy, Serbia, and France, which emerged through genome-wide homologous recombination between phylogroups 2a and 2b. Functional analysis of the recombinant core genome showed that pathways involved in the ATP-dependent transport and metabolism of amino acids, bacterial motility, and secretion systems were enriched for recombination. A survey of described virulence factors indicated the convergent acquisition of several accessory type 3 secreted effectors (T3SEs) among phylogenetically distinct lineages through integrative and conjugative element and plasmid loci. Finally, pathogenicity assays on watermelon and squash showed qualitative differences in virulence between strains of the same clonal lineage, which correlated with T3SEs acquired through various mechanisms of horizontal gene transfer (HGT). This study provides novel insights into the interplay of homologous recombination and HGT toward pathogen emergence and highlights the dynamic nature of P. syringae sensu lato genomes

Mechanical collision simulation of potato tubers

This paper presents the results of an investigation on internal stress progression and the explicit dynamics simulation of the bruising behavior of potato tubers under dynamic mechanical collision. Physical measurements, mechanical tests, advanced solid modeling, and engineering simulation techniques were utilized in the study. The tuber samples used in the simulation were reverse engineered and finite element analysis (FEA) was set up to simulate the collision-based bruising behavior of the potato tubers. The total number of identical tuber models used in the simulation was 17. The numerical data of the FEA results revealed useful stress distribution and mechanical behavior visuals. These results are presented in a frame that can be used to describe bruise susceptibility value on potato-like agricultural crops. The modulus of elasticity was calculated from compression test data as 3.12 MPa. Structural stresses of 1.40 and 3.13 MPa on the impacting (hitting) and impacted (hit) tubers (respectively) were obtained. These stress values indicate that bruising is likely to occur on the tubers. This research paper provides a useful how-to-do strategy to further research on complicated bruising investigations of solid-like agricultural products through advanced engineering simulation techniques. Practical applications: This research aims to simulate realistic dynamic deformation of potato tubers during mechanical collision, which is very hard to achieve through physical or analytical expressions. This is attractive because related food processing industries have shown their interest in determining the physical properties and bruising behavior of food/agricultural products using experimental, numerical, and engineering simulation methods so that it can be used in their food processing technology. Very limited data have been found available in the literature about the subject of FEM-based explicit dynamics simulation of solid-like agricultural crops such as the self-collision case of potato tubers (which is very important for indoor or outdoor potato processing). Comparative investigations on determination of modulus of elasticity are very limited as well. Most of the research focused on single calculation theory and linear static loading assumption-based FEM simulation solutions. Here, we report a “how-to-do” case study for dynamic self-collision simulation of potato tubers