Plasma corticosterone (CORT) measures are a common procedure to detect stress responses in rodents. However, the procedure is invasive and can influence CORT levels, making it less than ideal for monitoring CORT circadian rhythms. In the current paper, we examined the applicability of a non-invasive fecal CORT metabolite measure to assess the circadian rhythm. We compared fecal CORT metabolite levels to circulating CORT levels, and analyzed change in the fecal circadian rhythm following an acute stressor (i.e. blood sampling by tail veil catheter). Fecal and blood samples were collected from male adolescent rats and analyzed for CORT metabolites and circulating CORT respectively. Fecal samples were collected hourly for 24 h before and after blood draw. On average, peak fecal CORT metabolite values occurred 7-9 h after the plasma CORT peak and time-matched fecal CORT values were well correlated with plasma CORT. As a result of the rapid blood draw, fecal production and CORT levels were altered the next day. These results indicate fecal CORT metabolite measures can be used to assess conditions that disrupt the circadian CORT rhythm, and provide a method to measure long-term changes in CORT production. This can benefit research that requires long-term glucocorticoid assessment (e.g. stress mechanisms underlying health)., P. K. Thanos ... [et al.]., and Obsahuje seznam literatury
Increase of harmful radiation to the Earth’s surface due to ozone depletion results in higher exposure to harmful ultraviolet- B radiation (UV), while fluctuations in seawater salinity may alter water density, ionic concentration, nutrient uptake, and osmotic pressure. This study evaluated the effects of salinity and UV on metabolism and morphology of Acanthophora spicifera (M.Vahl) Børgesen. Water with 30 and 37 psu [g(salt) kg-1(sea water)] was used for experiments during 7 d of exposure to UV (3 h per day). We demonstrated that UV treatment predisposed, irrespective of salinity, A. spicifera to a decrease in its growth rate and cell viability, as well as affected its morphological parameters. After exposure to PAR + UVA + UVB (PAB), samples showed structural changes and damage, such as increasing cell wall thickness and chloroplast disruption. Our results indicate that UV led to dramatic metabolic changes and cellular imbalances, but more remarkable changes were seen in samples exposed to high salinity., D. T. Pereira, C. Simioni, L. C. Ouriques, F. Ramlov, M. Maraschin, N. Steiner, F. Chow, Z. L. Bouzon, É. C. Schmidt., and Obsahuje bibliografii
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) is one of the key enzymes involved in assimilation of CO2 in chloroplasts. Phylloplane microfungi and their metabolites have been reported to affect the physiology of host plants, particularly, their photosynthesis. However, information is lacking on the effect of these microflora on the physiology of chloroplasts. The current study emphasized the impact of two dominant phylloplane fungi, Aspergillus niger and Fusarium oxysporum, on activity of Rubisco in tomato chloroplasts. Ergosterol, which is a component of only fungal cell membranes and is not synthesized by plants, have been demonstrated to elicit activity of Rubisco. In the present study, it was demonstrated through in silico, in vitro, and in vivo approaches. Results demonstrated that the fungal metabolites, which contained ergosterol, could double Rubisco activity. Maximum carboxylation rate of Rubisco increased also in ergosterol-treated plants. Michaelis-Menten constant of Rubisco was also slightly affected. Ergosterol was found also to influence and enhance the binding of CO2 and ribulose-1,5-bisphosphate to Rubisco. Therefore we can postulate that the physiology of the chloroplast is probably influenced by phylloplane microfungi., J. Mitra, P. Narad, P. K. Paul., and Obsahuje bibliografii
Schisandra čínská neboli klanopraška čínská (Schisandra chinensis) se využívá v tradiční čínské medicíně pro své antimikrobiální, antivirové, antimykotické a antioxidační účinky. Hlavní účinnou složkou této rostliny jsou dibenzocyklooktadienové lignany. Bylo zjištěno, že tyto lignany blokují membránové ABC-transportéry, které jsou zodpovědné za mnohočetnou lékovou rezistenci při léčbě nádorů cytostatiky., Schisandra chinensis has been used in traditional Chinese medicine for its antimicrobial, antiviral, antimycotic and antioxidative effects. The main active compounds are dibenzocyclooctadiene lignans, which inhibit membrane ABC-transporters, responsible for the multi-drug resistance of cancer cells during their treatment by cytostatics., Ondřej Vymazal, Iva Slaninová., and Práce vznikla v rámci projektu AV ČR Otevřená věda
Lichens are characterized by the production of a large amount of secondary metabolites. Most of them are specific to these organisms. Lichenologists commonly use the metabolites to distinguish between phenotypically similar taxa. To achieve this aim, they use a plethora of detection methods, including spot reactions, chromatography, and microcrystalization tests. and Jiří Malíček.