The aim of this study was to measure expression levels of microRNAs (miRNAs) (miRNA-1, -15b and -21) in the rat myocardium after a single dose of ionizing radiation (6-7 Gy/min, total 25 Gy). The rats were treated with selected drugs (Atorvastatin, acetylsalicylic acid (ASA), Tadalafil, Enbrel) for six weeks after irradiation. MiRNAs levels were measured by RT-qPCR. Irradiation down-regulated miRNA-1 in irradiated hearts. In Tadalafil- and Atorvastatin-treated groups, miRNA-1 expression levels were further decreased compared with irradiated controls. However, Enbrel increased miRNA-1 level in irradiated hearts similarly to that in non-irradiated untreated group. Increase of miRNA-15b is pro-apoptotic in relationship with ischemia. Irradiation caused down-regulation of miRNA-15b. Administration of ASA in the irradiated group resulted in the increase of miRNA-15b expression compared to non-treated controls without irradiation. After Enbrel administration, miRNA-15b levels were overexpressed compared to non-treated normal group. MiRNA-21 belongs to the most markedly up-regulated miRNAs in response to cardiogenic stress. MiRNA-21 was increased nearly 2-fold compared to non-treated hearts whereas Tadalafil reduced miRNA-21 levels (about 40 %). Our study suggests that Enbrel and Tadalafil changed miRNAs expression values of the irradiated rats to the values of nonirradiated controls, thus they might be helpful in mitigation of radiation-induced toxicity., B. Kura, C. Yin, K. Frimmel, J. Krizak, L. Okruhlicova, R. C. Kukreja, J. Slezak., and Obsahuje bibliografii
Liriodendron tulipifera was exposed to gradually elevated ozone concentrations of 100-300 μg kg-1 in the naturally irradiated environment chamber. During 15 d of exposure to O3, net photosynthetic rate (PN) decreased and there was large difference between the control (C) and treatment with ozone (OT), while there was no significant difference in water use efficiency. Total chlorophyll content as well as the value of fluorescence parameter Fv/Fm decreased, while antioxidant enzyme activities related to ascorbate-glutathione cycle increased after 15 d of OT. Unchanged contents of ascorbate and glutathione indirectly suggest that the species hastened the antioxidant's oxidization/reduction cycle using enzymes instead of expanding their pool against oxidative stress. and S. Z. Ryang ... [et al.].
a1_Artemisia annua L. produces a compound called artemisinin that is a potent anti-malarial compound. However concentration of artemisinin within the plant is typically low (less than 0.8% of dry mass) and currently supply of the drug by the plant does not meet world demand. This investigation was carried out to determine whether high intensity light treatment would increase production of artemisinin in leaves of A. annua. Photoinhibition (14%) was induced in leaves of A. annua when they were subjected to 6 h of high-intensity light [2,000 μmol(photon) m-2 s-1]. Maximum photochemical efficiency of PSII showed a recovery of up to 95% within 24 h of light induced inhibition. During the light treatment, photochemical efficiency of PSII in leaves of the high-intensity light-treated plants was 38% lower than for those from leaves of plants subjected to a low-intensity-light treatment of 100 μmol(photon) m-2 s-1. Nonphotochemical quenching of excess excitation energy was 2.7 times higher for leaves treated with high-intensity light than for those irradiated with low-intensity light. Elevation in oxidative stress in irradiated leaves increased presence of reactive oxygen species (ROS) including singlet oxygen, superoxide anions, and hydrogen peroxide. Importantly, the concentration of artemisinin in leaves was two-fold higher for leaves treated with high-intensity light, as compared to those treated with low-intensity light. These results indicate that A. annua responds to high irradiance through nonphotochemical dissipation of light energy yet is subject to photoinhibitory loss of photosynthetic capacity. It can be concluded that A. annua is capable of rapid recovery from photoinhibition caused by high light intensity., a2_High light intensity also induced oxidative stress characterized by increased concentration of ROS which enhanced the content of artemisinin. Such a light treatment may be useful for the purpose of increasing artemisinin content in A. annua prior to harvest., M. E. Poulson, T. Thai., and Obsahuje seznam literatury
The effect of immunomodulatory agents on reparation processes in the thymus was studied in mice injured by a single sublethal or lethal dose of ionizing radiation ranging between 6.5-9.5 Gy. Reparation of thymus weight was not influenced by pretreatment with immunomodulators. Furthermore, the morphological picture did not exhibit appreciable differences between non-protected and protected groups, except for greater proliferation of fibroblasts and macrophages in protected animals.
The in vivo effects of recombinant human interleukin-1 receptor antagonist (rhIL-1Ra) administration on endogenous IL-1 levels in the circulation and conditioned media (CM) from different immunohematopoietic organ/tissues were studied in CBA mice under steady state and postirradiation conditions. In normal mice, constitutive IL-1 levels were demonstrated in the plasma, CM of peritoneal exudate cells and full-thickness skin explants with low or undetectable levels in CM of splenic and bone marrow cell suspensions. In irradiated mice (2 Gy, X rays) on day 3 post exposure a significant increase of IL-1 levels was seen in the circulation and CM of peritoneal exudate cells, with no significantly different levels in postirradiation bone marrow, spleen and skin. After rhIL-1Ra treatment of the animals (2 x 50 mg/mouse, i.p.), significantly elevated IL-1 levels were observed in the skin and CM of peritoneal exudate cells in normal mice, whereas slightly increased levels were detected in CM of splenic cells. The rhIL-1Ra administration in irradiated mice led to decreased IL-1 concentrations in the circulation, and CM of peritoneal exudate cells and skin. The results pointed out the importance of IL-1 secretion and receptor expression in the maintenance of homeostasis in steady state, as well as during recovery after irradiation. Modulatory effects of IL-1Ra on IL-1 production were dependent on basic endogenous IL-1 concentration., D. Bugarski, G. Jovčić, M. Kataranovski, Z. Ivanović, M. Petakov, N. Stojanović, P. Milenković., and Obsahuje bibliografii
We present a chlorophyll fluorometer module system which adapts the intensity to the individual leaf sample by adjusting the quantum flux density of the excitation light so that the fluorescence signal is kept constant. This is achieved by means of a feedback power adjustment of the fluorescence exciting laser diode. Thus, the intensity of the excitation light is adapted to the actual need of a particular sample for quantum conversion without applying exaggeratedly high quantum flux density. We demonstrate the influence of the initial laser power chosen at the onset of irradiation and kept constant during fluorescence rise transient within the first second. Examples are shown for measuring upper and lower leaf sides, a single leaf with different pre-darkening periods, as well as yellow, light green and dark green leaves. The novel excitation kinetics during the induction of chlorophyll fluorescence can be used to study the yield and regulation of photosynthesis and its related non-photochemical processes for an individual leaf. It allows not only to sense the present state of pre-darkening or pre-irradiation but also the light environment the leaf has experienced during its growth and development. Thus, the individual physiological capacity and plasticity of each leaf sample can be sensed being of high importance for basic and applied ecophysiological research which makes this new methodology both innovative and informative. and A. Barócsi ... [et al.].
Excess solar radiation under hot climate can lead to decline in photosynthetic activity with detrimental effects on growth and yield. The aim of this study was to evaluate the use of a transparent plastic roof as shading for diurnal changes in photosynthetic gas exchange, chlorophyll fluorescence, fruit set and quality of mango (Mangifera indica L.) cv. 'Nam Dok Mai' growth in the field conditions. Fully expanded leaves were examined either shaded by the plastic roof or sunlit under natural conditions. Leaf temperature and leaf-to-air vapour pressure deficit of the shaded leaves measured on the clear day were lowered compared to those of the sunlit leaves. It resulted in increased stomatal conductance and photosynthetic rates of the shaded leaves compared to those of the sunlit leaves, especially from the morning to midday. Furthermore, the reversible decrease of the maximal quantum yield of PSII was more pronounced in the sunlit leaves than that in the shaded ones. Shading increased the total fruit number; the shaded fruits developed better external color than that of the sun-exposed fruits. Our results indicated that shading could maintain the high photosynthetic activity by reducing stomatal limitations for carbon supply and was effective in alleviating the photoinhibitory damage to PSII during bright and clear days with excessive radiation. Finally, shading could increase the number of fruits and improve mango peel color., K. Jutamanee, S. Onnom., and Obsahuje bibliografii
The intenzity of illumination of a solar panel depends on the angle between its normal and the direction of the solar beam and it can be, consequently, enhanced for the panel tracked towards the sun. The aim of the paper is to compare the intensity of illumination of the fixed (non-tracking) panel and illumination of the panel with one or two tracking axes. The annual irradiation and irradiation in individual months was determined using the coefficient of contamination Z = 4 characterizing the atmosphere in towns. The data of the sun elevation and azimuth during one year for the latitude 50° N were utilized for the calculation. and Intenzita ozáření slunečního panelu závisí na úhlu, který svírá jeho normála se směrem slunečních paprsků a může se proto zvýšit, bude-li se panel natáčet za sluncem. Cílem této práce je porovnat intenzitu ozáření pevného (nenatáčeného) panelu a panelu natáčeného za sluncem kolem jedné, případně dvou os. Byla určena iradiace panelu za celý rok i pro jednotlivé měsíce při koeficientu znečištění atmosféry Z = 4, který charakterizuje atmosféru ve městech. Pro výpočet byla využita data výšky slunce nad obzorem a azimutu v průběhu roku pro 50. stupeň severní šířky.
Experimental studies in animals provide relevant knowledge about pathogenesis of radiation-induced injury to the central nervous system. Radiation-induced injury can alter neuronal, glial cell population, brain vasculature and may lead to molecular, cellular and functional consequences. Regarding to its fundamental role in the formation of new memories, spatial navigation and adult neurogenesis, the majority of studies have focused on the hippocampus. Most recent findings in cranial radiotherapy revealed that hippocampal avoidance prevents radiation-induced cognitive impairment of patients with brain primary tumors and metastases. However, numerous preclinical studies have shown that this problem is more complex. Regarding the fact, that the radiation-induced cognitive impairment reflects hippocampal and non-hippocampal compartments, it is highly important to investigate molecular, cellular and functional changes in different brain regions and their integration at clinically relevant doses and schedules. Here, we provide a literature review in order support the translation of preclinical findings to clinical practice and improve the physical and mental status of patients with brain tumors.
Because the transformation of protochlorophyllide (Pchlide) to chlorophyllide (Chlide) is an irradiation-dependent process, it is at the heart of the photosynthetic membrane biogenesis, turnover, and adaptation to changes of the environment. I review here the new data published during the year 2004 on Pchlide reduction to Chlide.