Evaluation of chlorophyll fluorescence in different densities of spring barley

Over the period 2008–2009, field experiments were carried out at the Lithuanian Institute of Agriculture on an Endocalcari-Epihypogleyic Cambisol (CMg-p-w-can). The study was aimed to establish the effects of spring barley crop stand density on the chlorophyll fluorescence and to estimate the relationship between grain yield and chlorophyll fluorescence value. The tests involved three spring barley varieties—Aura DS, Barke and Gustav. The three different stand densities were formed with seed rates of two, four and six million viable seeds per hectare. Our research findings indicated that increasing spring barley stand density did not exert any negative influence on major photosynthetic processes and did not result in any significant qualitative changes in light harvesting system. A significant varietal (factor B) influence was established on minimum fluorescence (F _o) and maximum fluorescence (F _m) values after short dark adaptation indicators (F _fact. = 19.66** and F _fact. = 9.33**, respectively). Growth stage (factor C) significantly influenced all fluorescence indicators—Fo, Fm and quantum efficiency of PSII after short dark adaptation (F _v/F _m)—in the five cases of the six tested. A significant effect of variety and growth stage interaction (B × C) was determined for 66.7% of the tested cases. The article presents a correlation between the grain yield of spring barley and fluorescence parameters. In most cases, the correlation was strong and significant. The interaction between the fluorescence parameters for individual varieties was responsible for 53.8–76.2% of grain yield data variation, which averaged over all varieties, amounted to 21.9–46.1%.     

Investigation of unmatured hematopoietic cell migration in a mouse model

The objective of this work was to examine the migration of transplanted bone marrow hematopoietic lin⁻ cell population using the BALB/c mouse contact hypersensitivity model in vivo and to determine the time point at which they reach the site of injury (paw edema) as well as other undamaged organs, such as liver and spleen. Female BALB/c mice with induced contact hypersensitivity reaction were intravenously injected with 1×10⁶ cells/mouse lin⁻ cells, labeled with PKH67. The presence of lin⁻ stained cells in mouse tissue sections was evaluated by fluorescent microscopy. After one hour, the labeled cells were found in mice paw edema and liver, and after 4 hours in spleen tissue. Migrated hematopoietic lin⁻ cells remained in liver tissue for 48 h, and in spleen and paw edema at least for 72 h. Migrated stained cells in untreated paw were not found. The results prove that bone marrow unmatured hematopoietic cells are first found in paw edema, where they participate in the inhibition of tissue inflammation; these cells subsequently migrate to the liver and are found in the spleen shortly afterwards.     

Effect of genotype and medium composition on linseed (<Emphasis Type="Italic">Linum usitatissimum</Emphasis>) ovary culture

Breeding linseed (Linum usitatissimum L.) using haploid techniques allows breeders to develop new cultivars in a shorter time period. Many research groups successfully created new linseed genotypes through anther culture; however ovary culture has been the subject of only a few earlier studies. In the present study, the effect of genotype and growth regulators combination on callus induction and shoots regeneration in ovary culture of nine commercially important linseed cultivars was investigated. Ovaries were cultured on modified MS medium supplemented with three different combinations of plant growth regulators. Variable callogenic responses were expressed by all of the genotypes tested on different induction media. The results suggested that specific combination of growth regulators for callus induction must be designed for each genotype. Shoot regeneration from ovary derived callus is a critical phase of the whole gynogenetic process. Differences in adventitious shoot formation frequency among genotypes were demonstrated and four responsive genotypes have been selected. Ovary derived callus from cultivar ‘Mikael’ manifested the highest adventitious shoot formation frequency with a high number of shoots per explant. The optimum ratio of growth regulators for shoot regeneration was shown to depend on the genotype. Cultivars ‘Linola’, ‘Mikael’ and ‘Szaphir’ showed the highest shoot regeneration frequency when callus had originated on induction medium supplemented with 2 mg L⁻¹ BAP and 2 mg L⁻¹ NAA, while combination of 1 mg L⁻¹ BAP and 2 mg L⁻¹ IAA promoted shoot formation in ovary-derived callus of ‘Barbara’. The highest rate of shoots per explant has been obtained in second subculture.     

<Emphasis Type="Italic">In vitro</Emphasis> culture of <Emphasis Type="Italic">Chrysanthemum</Emphasis> plantlets using light-emitting diodes

Effects of illumination spectrum on the morphogenesis of chrysanthemum plantlets (Chrysanthemum morifolium Ramat. ‘Ellen’) grown in vitro were studied using an illumination system consisting of four groups of light-emitting diodes (LEDs) in the following spectral regions: blue (450nm), red (640nm), red (660nm), and far-red (735nm). Taking into account all differences in shoot height, root length, and fresh and dry weight (FW and DW, respectively), observed while changing the total photon flux density (PFD), the optimal total PFD for growth of chrysanthemum plantlets in vitro was estimated. For 16 h photoperiod and typical fractions of the spectral components (14%, 50%, 28%, and 8%, respectively), the optimal total PFD was found to be 40 μmol m⁻² s⁻¹. Our study shows that the blue component in the illumination spectrum inhibits the plantlet extension and formation of roots and simultaneously increases the DW to FW ratio and content of photosynthetic pigments. We demonstrate photomorphogenetic effects in the blue region and its interaction with the fractional PFD of the far-red spectral component. Under constant fractional PFD of the blue component, the root number, length of roots and stems, and fresh weight of the plantlets have a correlated nonmonotonous dependence on the fractional PFD of the far-red component.     

Relationships of Oxygen Consumption, Hemodynamics, and Heart Rate Variability with the Functional Class of Coronary Artery Disease Patients

The functional classes (FCs) established according to the criteria of the New York Heart Association were tested for association with oxygen consumption, the state of central hemodynamics, and heart rate (HR) variability in coronary artery disease (CAD) patients. Oxygen consumption, central hemodynamics, and HR variability at rest and during exercise were assayed in 146 CAD patients and 30 healthy individuals (the control group). It was established that the peak oxygen consumption (VO_2max), anaerobic threshold, pulmonary ventilation, systolic and minute blood volume at the threshold load (TL), and HR variability in a supine position significantly decrease and the total vascular peripheral resistance at rest and during exercise increases with increasing FC in CAD patients. The closest correlation of FC was revealed with physical working capacity, anaerobic threshold, age, and peak oxygen consumption. Moderate correlations were established with the chronotropic function of the heart at the threshold load, HR variability, the high- and low-frequency components of the cardiac rhythm at TL, pulmonary ventilation, stroke volume at rest and at TL, and the carbon dioxide ventilation equivalent at TL. In healthy individuals, the peak oxygen consumption closely correlated with the HR variability, the very low frequency component at TL, and physical capacity. With an increase in FC in CAD patients, peak oxygen consumption became more tightly associated with the chronotropic function and the hemodynamic components at TL than with the HR variability in a supine position or at TL.     

Redox reactions of the FAD-containing apoptosis-inducing factor (AIF) with quinoidal xenobiotics: a mechanistic study

Mitochondrial apoptosis-inducing factor (AIF) is a FAD-containing protein that under certain conditions translocates to the nucleus and causes a programmed cell death, apoptosis. The apoptogenic action of AIF is redox controlled as the NADH-reduced AIF dimer has lower affinity for DNA than the oxidized monomer. To gain further insights into the mechanism of AIF, we investigated its interaction with a series of quinone oxidants, including a number of anticancer quinones. Our data indicate that the NADH:quinone oxidoreduction catalyzed by AIF follows a “ping-pong” scheme, with the reductive half-reaction being rate-limiting and the FADH⁻–NAD⁺ charge-transfer complex serving as an electron donor. AIF is equally reactive toward benzo- and naphthoquinones, but may discriminate structures with a higher number of aromatic rings. The reactivity of quinones is mainly defined by their one-electron reduction potential, whereas the size and nature of the substituents play a minor role. AIF is unlikely to significantly contribute to bioreductive activation of low-potential quinoidal anticancer quinones. However, high-potential quinones, e.g. a toxic natural compound naphthazarin, maintain AIF in the oxidized state when a significant excess of NADH is present. Thus, these compounds may prevent the accumulation of the reduced form of AIF in vivo, and enhance AIF-mediated apoptosis.     

Fatty acid amide hydrolase is a key regulator of endocannabinoid-induced myocardial tissue injury

Previous studies have suggested that increased levels of endocannabinoids in various cardiovascular disorders (e.g., various forms of shock, cardiomyopathies, atherosclerosis) through the activation of CB(1) cannabinoid receptors may promote cardiovascular dysfunction and tissue injury. We have investigated the role of the main endocannabinoid anandamide-metabolizing enzyme (fatty acid amide hydrolase; FAAH) in myocardial injury induced by an important chemotherapeutic drug, doxorubicin (DOX; known for its cardiotoxicity mediated by increased reactive oxygen and nitrogen species generation), using well-established acute and chronic cardiomyopathy models in mice. The DOX-induced myocardial oxidative/nitrative stress (increased 4-hydroxynonenal, protein carbonyl, and nitrotyrosine levels and decreased glutathione content) correlated with multiple cell death markers, which were enhanced in FAAH knockout mice exhibiting significantly increased DOX-induced mortality and cardiac dysfunction compared to their wild type. The effects of DOX in FAAH knockouts were attenuated by CB(1) receptor antagonists. Furthermore, anandamide induced enhanced cell death in human cardiomyocytes pretreated with FAAH inhibitor and enhanced sensitivity to ROS generation in inflammatory cells of FAAH knockouts. These results suggest that in pathological conditions associated with acute oxidative/nitrative stress FAAH plays a key role in controlling the tissue injury that is, at least in part, mediated by the activation of CB(1) receptors by endocannabinoids.