The apolipoprotein A-V (apo A-V) plays an important role in regulation of triglyceride (TG) concentration in serum. To better understand how apo A-V affects triglyceridemia and glucoregulation, the lipoprotein lipase (LPL) activity was determined using intravenous fat tolerance test (IVFTT) and oral glucose tolerance test (oGTT) was performed in carriers of apolipoprotein A-V gene ( APOAV) variants known to be associated with increased triglyceridemia. Twelve carriers of 19W variant, 16 carriers of -1131C variant, 1 combined heterozygote and 16 control subjects homozygous for wild type variants (19S/-1131T) were selected from a population sample and matched with respect to body mass index and age. The APOAV variants carriers had increased TG, very low density lipoprotein-TG, and apo B concentrations (p < 0.05). The LPL activity evaluated as k2 rate constant for clearance of Intralipid® was 14 % lower in APOAV variants carriers. The depression of nonesterified fatty acids (NEFA) concentration after glucose load was delayed in APOAV variants carriers in spite of the same insulinemia and glycemia. Our results suggest that variants of APOAV combined with increased triglyceridemia are associated with lower LPL activity in vivo and with disturbances of regulation of NEFA concentration after glucose load., J. Kovář, V. Adámková., and Obsahuje bibliografii a bibliografické odkazy
Zachovalé pralesovité porosty patří v České republice k ojedinělým úkazům. Přestože lesních rezervací u nás nalezneme celou řadu, ty skutečně málo dotčené nebo dlouhodobě se vyvíjející bez výrazných zásahů člověka představují pouhý zlomek. Zřejmě nejvýznamnějšími pralesům blízkými lesy jsou Boubínský prales nebo Hraničník na Šumavě a Žofínský prales v Novohradských horách. V minulosti byly málo ovlivněny činností člověka a dosti dlouhou dobu se v nich lesnicky nehospodaří. Příznivé podmínky pro přežívání vzácných druhů lišejníků a dalších organismů na těchto lokalitách jsou však omezeny jejich malou rozlohou. S větší plochou pralesa vzrůstají předpoklady pro dlouhodobou koexistenci různých fází vývoje přírodního lesa s dostatečnou variabilitou mikrostanovišť a tím se zároveň zvyšuje šance na přežití úzce specializovaných druhů. Žofínský prales patří k nejstarším chráněným územím v Evropě, je chráněn již od r. 1838. Národní přírodní rezervace Žofínský prales zaujímá v současné době 102 ha; jádrové území s pralesovitými porosty však tvoří jen 74,5 ha. Převažující dřevinou je buk, početně jsou zastoupeny také smrk a jedle. Z lichenologického hlediska jde o zcela unikátní lokalitu. Na území rezervace bylo zaznamenáno 247 druhů lišejníků, což představuje přibližně 16 % všech známých druhů z České republiky. Z hlediska epifytických a zejména epixylických (rostoucích na dřevě v různém stupni rozkladu) lišejníků je Žofínský prales zřejmě místem s největší rozmanitostí lišejníků na našem území., Žofín virgin forest forms a unique landscape, which probably predominated in mountain areas before the arrival of humans. Because of the huge diversity of lichens, the reserve is one of the most valuable lichenological localities in the Czech Republic. Many lichen taxa were recorded here for the first time in this country., and Jiří Malíček, Zdeněk Palice.
The effect of salinity on some morpho-physiological characteristics in lisianthus cultivars was investigated. Cultivars namely, Blue Picotee (C1), Champagne (C2), Lime Green (C3), and Pure White (C4), were subjected to salt stress (0-60 mM NaCl) in a sand culture and their responses were measured. Our results showed that as a salinity level increased, growth parameters, relative water content, photosynthetic pigments, and gas-exchange characteristics decreased in all cultivars, while root fresh mass, root/shoot length ratio, electrolyte leakage, and a malondialdehyde content increased. However, the changes were less pronounced in C3 and C4 compared to C1 and C2. The regression analysis of the relationship between salinity levels and seedling height or root/shoot length ratio defined two groups with different slope coefficients: C1 and C2 as salt-sensitive cultivars and C3 and C4 as salt-tolerant cultivars. Shoot dry mass and leaf area tolerance indices were less affected by salinity in C3 and C4 compared to those in C1 and C2. Further, C3 and C4 showed higher photosynthetic rates, greater stomatal conductances, and accumulated greater K+ and Ca2+ contents and K+/Na+ ratios in roots and shoots compared to those in C1 and C2. The results suggests that C3 and C4 could be recommended as resistant cultivars due to maintaining higher growth, water balance, leaf gas exchange, ion compartmentalization, and lower lipid peroxidation in response to salinity compared to C1 and C2., N. Ashrafi, A. Rezaei Nejad., and Obsahuje bibliografii
The aim of the present study was to define the stress-induced pattern of cytosolic glucocorticoid receptor (GR) and Hsp70 protein in the liver of male Wistar rats exposed to different stress models: acute (2 h/day) immobilization or cold (4 °C); chronic (21 days) isolation, crowding, swimming or isolation plus swimming and combined (chronic plus acute stress). Changes in plasma levels of corticosterone were studied by radioimmunoassay (RIA). The results obtained by Western immunoblotting showed that both acute stressors led to a significant decrease in cytosolic GR and Hsp70 levels. Compared to acute stress effects, only a weak decrease in the levels of GR and Hsp70 was demonstrated in chronic stress models. Chronically stressed rats, which were subsequently exposed to novel acute stressors (immobilization or cold), showed a lower extent of GR down-regulation when compared to acute stress. The exception was swimming, which partially restores this down-regulation. The observed changes in the levels of these major stress-related cellular proteins in liver cytosol lead to the conclusion that chronic stressors compromise intracellular GR down-regulation in the liver., D. Filipović, L. Gavrilović, S. Dronjak, M. Demajo, M. B. Radojčić., and Obsahuje bibliografii a bibliografické odkazy
Pigments absorbing 350-1,050 nm radiation have had an important role on the Earth for at least 3.5 billion years. The ion pumping rhodopsins absorb blue and green photons using retinal and pump ions across cell membranes. Bacteriochlorophylls (BChl), absorbing in the violet/blue and near infra red (NIR), power anoxygenic photosynthesis, with one photoreaction centre; and chlorophylls (Chl), absorbing in the violet/blue and red (occasionally NIR) power oxygenic photosynthesis, with two photoreaction centres. The accessory (bacterio)chlorophylls add to the spectral range (bandwidth) of photon absorption, e.g., in algae living at depth in clear oceanic water and in algae and photosynthetic (PS) bacteria in microbial mats. Organism size, via the package effect, determines the photon absorption benefit of the costs of synthesis of the pigment-protein complexes. There are unresolved issues as to the evolution of Chls vs. BChls and the role of violet/blue and NIR radiation in PS bacteria., A. W. D. Larkum, R. J. Ritchie, J. A. Raven., and Obsahuje bibliografické odkazy
Chloroplasts of barley plants grown under red light (RL, 660 nm) dramatically differed from the chloroplasts of plants raised under blue light (BL, 450 nm) or control plants (white light). The chloroplasts under RL had an extensive membrane system with high stacking degree and disordered irregular shaped stacks (shaggy-formed grana). After 5 h in darkness, dynamic rearrangements of chloroplast architecture in RL- and especially BL-grown plants were restricted compared with control plants. The light spectral quality affected the content and proportions of photosynthetic pigments. The leaves of RL-grown plants had the increased ratio of low-temperature fluorescence bands, F741/F683, corresponding to emission of PSI and PSII, respectively. This increase can be related to specific architecture of chloroplasts in RL-treated plants, providing close spacing between the two photosystems, which enhances energy transfer from PSII to PSI and facilitates the movement of LHCII toward PSI., G. V. Kochetova, O. B. Belyaeva, D. S. Gorshkova, T. A. Vlasova, E. M. Bassarskaya, T. V. Zhigalova, O. V. Avercheva., and Obsahuje bibliografii
Competition is a major force organizing ant communities and results in co-occurring species evolving different strategies for foraging and use of space. Territorial species, as top dominants exclude each other, while shaping the local ant communities both qualitatively and quantitatively. In this study we examined how two territorial species, Formica polyctena and Lasius fuliginosus, can coexist in adjacent territories over long periods of time, and whether they affect co-occurring species of ants in different ways. Field observations in the absence and in the presence of baits were carried out around a L. fuliginosus nest complex surrounded by a polydomous F. polyctena colony in S Finland in 2007–2009. Both species controlled their territories, but were affected by changes in the abundance of the other species and the distance from L. fuliginosus’ main nest. They did not have the same effect on the subordinate species in the absence of baits, but the abundance of Myrmica spp. recorded at baits was negatively affected by both of the territorial species. The preferences of the different species for the artificial food sources differed: L. fuliginosus and F. polyctena preferred tuna to honey and Myrmica spp. honey to tuna. More individuals of the subordinate species were recorded in the territory of F. polyctena than of L. fuliginosus, although conflicts with this territorial species were also recorded. During the three years of the study almost no overlaps in the territories of the two territorial species were recorded, and there were mostly minor shifts in the boundaries of the territories. Differences between the two territorial species in their use of space and competitive effects ensured their coexistence at this particular site in Finland., Wojciech Czechowski ... [et al.]., and Obsahuje seznam literatury
Leaf senescence is always associated with decline in photosynthesis, consequently a loss of cellular sugar. On the other hand, execution of senescence program needs energy and leaves, therefore, tend to collect sugars from other sources to sustain energy homeostasis. This sugar reprogramming induced by loss of sugar involves operation of a complex catabolic network. The exact molecular mechanism of induction and regulation of the network, however, is not fully resolved but the current literature available suggests sugar starvation as a signal for induction of several senescence-associated genes including the genes coding for the enzymes for degradation of cellular constituents and their conversion to respiratory sugars. The late expression of genes coding for the cell wall hydrolases and enhancement in the activity of these enzymes late during senescence are indicative of the cell wall polysaccharides as the last source of sugars to sustain energy homeostasis for execution of the senescence program., B. Biswal, J. K. Pandey., and Obsahuje bibliografické odkazy