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.].
Excitation kinetics based on feedback regulation of chlorophyll (Chl) fluorescence of leaves measured with the chlorophyll fluorometer, FluoroMeter Modul (FMM), are presented. These kinetics showed the variation of excitation light (laser power, LP) regulated by the feedback mechanism of the FMM, an intelligent Chl fluorometer with embedded computer, which maintains the fluorescence response constant during the 300-s transient between the dark- and light-adapted state of photosynthesis. The excitation kinetics exhibited a rise of LP with different time constants and fluctuations leading to a type of steady state. The variation of excitation kinetics were demonstrated using the example of primary leaves of etiolated barley seedlings (Hordeum vulgare L. cv. Barke) during 48 h of greening in the light with gradual accumulation of Chl and development of photosynthetic activity. The excitation kinetics showed a fast rise followed by a short plateau at ca. 30 s and finally a slow constant increase up to 300 s. Only in the case of 2 h of greening in the light, the curve reached a stable steady state after 75 s followed by a slight decline. The final LP value (at 300 s of illumination) increased up to 12 h of greening and decreased with longer greening times. The active feedback mechanism of the FMM adjusted the excitation light during the measurement to the actual photosynthetic capacity of the individual leaf sample. In this way, the illumination with excessive light was avoided. The novel excitation kinetics can be used to characterize health, stress, disease, and/or product quality of plant material., C. Buschmann ... [et al.]., and Obsahuje bibliografii
This paper presents the procedure for designing electromagnetic bladed wheel excitation. This procedure comes from phase-synchronization of multiple electromagnets distributed around the wheel with a movement of the blade to obtain its resonant vibration. This procedure can be used with merit for dynamic tests of inter-blade couplings. The verification was performed on the tested wheel using two-point electromagnetic excitation of blades under rotation. and Obsahuje seznam literatury
The present status of research on the generation of spiral patterns in the responsive density wave theory is discussed. The latter is based on a conjecture of symmetry breaking in the equations of motion of stellar orbits in differentially rotating stellar disks by an oval perturbation growing with time. Analytical approaches based on first-order epicyclic approximation as well as computer experiments are performed to investigate the consequences of this working hypothesis.
Vascular smooth muscle cells (VSMC) display considerable phenotype plasticity which can be studied in vivo on vascular remodeling which occurs during acute or chronic vascular injury. In differentiated cells, which represent contractile phenotype, there are characteristic rapid transient changes of intracellular Ca2+ concentration ([Ca2+]i), while the resting cytosolic [Ca2+]i concentration is low. It is mainly caused by two components of the Ca2+ signaling pathways: Ca2+ entry via L-type voltagedependent Ca2+ channels and dynamic involvement of intracellular stores. Proliferative VSMC phenotype is characterized by long-lasting [Ca2+]i oscillations accompanied by sustained elevation of basal [Ca2+]i. During the switch from contractile to proliferative phenotype there is a general transition from voltagedependent Ca2+ entry to voltage-independent Ca2+ entry into the cell. These changes are due to the altered gene expression which is dependent on specific transcription factors activated by various stimuli. It is an open question whether abnormal VSMC phenotype reported in rats with genetic hypertension (such as spontaneously hypertensive rats) might be partially caused by a shift from contractile to proliferative VSMC phenotype., E. Misárková, M. Behuliak, M. Bencze, J. Zicha., and Obsahuje bibliografii
Excitation-emission maps were constructed by measuring emission spectra from tobacco thylakoids and from thylakoids and intact cells of the cyanobacterium Synechocystis 6803. The measurement of such maps is greatly facilitated by the current diode-array detector technology. We show that excitation-emission maps are valuable tools for studies of the structure and energy transfer pathways in photosynthetic systems. and Mika Keränen, Eva-Mari Aro, Esa Tyystjärvi.
The effects of Lathyrus sativus neurotoxin were studied on the cell membrane potential and cellular cation composition in Retzius nerve cells of the leech Haemopis sanguisuga, with ion-selective microelectrodes using liquid ion-exchangers. Bath application of 10-4 mol/l Lathyrus sativus neurotoxin for 3 min depolarized the cell membrane potential and decreased the input resistance of directly polarized membrane in Retzius neurons. At the same time the cellular Na+ activity increased and cellular K+ activity decreased with slow but complete recovery, while the intracellular Ca2+ concentration was not changed. Na+-free Ringer solutions inhibited the depolarizing effect of the neurotoxin on the cell membrane potential. Zero-Ca2+ Ringer solution or Ni2+-Ringer solution had no influence on the depolarizing effect of the neurotoxin on the cell membrane potential. It is obvious that the increase in membrane conductance and depolarization of the cell membrane potential are due to an influx of Na+ into the cell accompanied by an efflux of K+ from the cell., D. Cemerikić, V. Nedeljkov, S. Lopičić, S. Dragović, B. Beleslin., and Obsahuje bibliografii
Activation of autophagy suppresses ovarian cancer (OC). This in vitro study investigated whether the anti-tumour effect of exendin-4 against OC involves modulation of autophagy and figured out the possible mechanisms of action. SKOV-3 and OVCAR-3 cells (1 × 105/ml) were cultured in DMEM medium and treated with exendin-4 in the presence or absence of chloroquine (CQ), an autophagy inhibitor. In some cases, cells were also treated with exendin- 4 with or without pre-treatment with compound C (CC), an AMPK inhibitor, or insulin-like growth factor (IGF-1), a PI3K/Akt activator. Exendin-4 increased expression of beclin-1 and LC3I/II, suppressed expression of p62, reduced cell survival, migration, and invasion, and increased cell apoptosis and LDH release in both SKOV-3 and OVCAR-3 cells. Besides, exendin-4 reduced phosphorylation of mTORC1, 6SK, 4E-BP1, and Akt but increased phosphorylation of AMPK in both cell lines. These effects were associated with down-regulation of Bcl-2, suppression of nuclear phosphorylation of NF-κB p65, and increased expression of Bax and cleaved caspases 3/8. Chloroquine completely prevented the inhibitory effects of exendin-4 on the cell survival, Bcl-2, NF-κB, and cell invasiveness and abolished its stimulation of cell apoptosis and LDH release. Moreover, only the combined treatment with IGF-1 and CC completely abolished the observed effect of exendin-4 on the expression of beclin-1, LC3I/II, p62, as well as on cell survival, apoptosis, and LDH release. Exendin-4 exhibits a potent anti-tumour cytotoxic effect in SKOV-3 and OVCAR-3 cells by activating the markers of autophagy, mediated by activation of AMPK and inhibition of Akt.
It is known that excessive sympathetic activity and oxidative stress are enhanced in obesity. This study aimed to clarify whether exercise training (ET) attenuates sympathetic activation and oxidative stress in obesity. The obesity was induced by highfat diet (HFD) for 12 weeks. Male Sprague-Dawley rats were assigned to four groups: regular diet (RD) plus sedentary (RD-S), RD plus ET (RD-ET), HFD plus sedentary (HFD-S), and HFD plus ET (HFD-ET). The rats in RD-ET and HFD-ET groups were trained on a motorized treadmill for 60 min/day, five days/week for 8 weeks. The sympathetic activity was evaluated by the plasma norepinephrine (NE) level. The superoxide anion, malondialdehyde and F2-isoprostanes levels in serum and muscles were measured to evaluate oxidative stress. The ET prevented the increases in the body weight, arterial pressure and white adipose tissue mass in HFD rats. The NE level in plasma and oxidative stress related parameters got lower in HFD-ET group compared with HFD-S group. We have found decreased mRNA and protein levels of toll-like receptor (TLR)-2 and TLR-4 by ET in HFD rats. These findings suggest that ET may be effective for attenuating sympathetic activation and oxidative stress in diet-induced obesity., G. Li, J.-Y. Liu, H.-X. Zhang, Q. Li, S.-W. Zhang., and Obsahuje bibliografii
This section contains information about two exhibitions realized in the year 2007. The first review is devoted to the exhibition named
White Beauty which took place in Frenštát pod Radhoštěm. A set of embroidered textiles from the private collection of Mr and Mrs Divín from Zubří was presented within the framework of the exhibition.
This collection covers the development of patterns and variants of Zubří embroidery within the past 100 years. The displayed set of embroidered textiles is significant because it assembles a number of objects connected to one locality - Zubří and its immediate vicinity. The collection also documents work of several generations of embroiderers from this locality. Several dozens of covers, blankets, fancy handkerchiefs, headdresses and other objects decorated by Zubří embroidery, were presented there. The atmosphere was intensified by a quantity of photographs and reproductions of working embroiderers and women dressed in traditional costumes.
In 2007, the Museum of Southeastern Moravia in Zlín opened a new permanent exhibition in Luhačovice called Luhačovice Known and Unknown. The aim of the exhibition is to show visitors Luhačovice at the turn of the 19th and 20th centuries as a town at the centre of
traditional ethnographical region Luhačovické Zálesí, to point out that Luhačovice is a health resort, and to introduce it as a place between a village and a spa. Presented material is placed in seven exhibition spaces. It gives an idea of different aspects of the material and non-material culture of the town, reminds of prominent personalities as well as specific features of this locality. and Tento abstrakt je společný pro 2 zprávy uvedené v oddílu Výstavy