Acta Biologica Hungarica最新文献

In the present study the effect of capsaicin was studied on PD model flies expressing human alpha synuclein. First the potential of scavenging superoxide anion and free radicals by capsaicin at doses of 20, 40, 80 and 100 μM was estimated. The PD flies were allowed to feed separately on the diet containg 20, 40, 80 and 100 μM of capsaicin, respectively, for 24 days. After 24 days of exposure, fly head homogenate was prepared from each group and was used to estimate glutathione (GSH), protein carbonyl (PC), dopamine content, lipid peroxidation (LPO), glutathione-S-transferase (GST) and monoamine oxidase (MAO) activity. A dose dependent significant increase in the potential of scavenging superoxide anions and free radicals by capsaicin was observed for the doses of 20, 40, 80 and 100 μM. The exposure of capsaicin not only significantly increased the GSH (max. by 1.37-fold), and dopamine (max. by 1.56-fold) content but also reduced LPO (max. by 1.8-fold), GST (max. by 1.26-fold), MAO activities (max. by 1.60-fold) and PC content (max. by 1.95-fold), compared to unexposed PD flies (p < 0.05). The results suggest the protective role of capsaicin against the PD symptoms.

We tested the amyloid fibril formation inhibitory effect of seven teas diluted in 55% ethanol at pH 7.0 at a protein concentration of 0.15 mg/ml α-chymotrypsin. In the experiments we investigated the formation and inhibition of amyloid fibrils by turbidity measurements, aggregation kinetics experiments and Congo red binding assay. The results suggest that the different teas effectively inhibit the formation of amyloidlike fibrils. The two most potent inhibitors were peppermint and melilot, extracts which almost completely inhibited the formation of aggregates in 5-fold dilution. The inhibitory effect on the aggregation formation of melilot and peppermint extracts was concentration dependant. The extent of inhibition was found to be proportional with the total concentration of phenolic compounds.

Selenium (Se) is an essential element for animals and humans, but not plants. However, the capacity of some plants to accumulate and transform Se into bioactive compounds has important implications for human nutrition and health. In this study, sunflower (Helianthus annuus) and maize (Zea mays) seedlings were cultivated in soil to investigate the effect of different rates of sodium selenite (1-90 mg kg^-1 soil) and sodium selenate (1-30 mg kg^-1 soil) on absorption and translocation of Se and sulphur (S). Sodium selenate decreased growth of sunflower roots at all applied rates and of maize roots at the highest rate applied. In contrast, sodium selenite up to 30 mg kg^-1 for sunflower and 3 mg kg^-1 for maize resulted in increased shoot and root growth. An increase in Se concentration in soil resulted in an increase in Se and a decrease in S accumulation in roots and shoots of both maize and sunflower. Selenium translocation from roots to shoot was higher in sunflower than maize. Root-to-shoot translocation of Se was 5 to 30 times greater in sunflower and 0.4 to 3 times greater in maize in the sodium selenate than sodium selenite treatments. Sunflower, as a Se-hyperaccumulator with up to 1.8 g kg^-1 in shoots (with no significant decrease in shoot biomass) can be a valuable plant in biofortification to improve animal/human nutrition, as well as in phytoremediation of contaminated sites to restore ecosystem services.

Eutrophication and enhanced external nutrient loading of lakes and seas are most clearly reflected by increased cyanobacterial blooms, which are often toxic. Freshwater cyanobacteria produce a number of bioactive secondary metabolites, some of which have allelopathic properties, significantly influencing the biological processes of other algae, thereby affecting species composition and succession of the phytoplankton. The goal of this work was to investigate the influence of bloom-forming cyanobacterial exudates on the photophysiology of the green alga Scenedesmus quadricauda by chlorophyll fluorescence analysis. We were able to prove the effect of algal cell-free filtrates on the performance of S. quadricauda and demonstrate for the first time that the freshwater picocyanobacterium Cyanobium gracile has strong negative impact on the coexisting green alga. Neither the cyanotoxin (MYC, CYN and ATX) producing, nor the non-toxic strains showed any systematic effect on the production of S. quadricauda. Various strains of the cyanobacterium Cylindrospermopsis raciborskii inhibited the performance of the green alga independently of their origin. Our results urge further studies for a better understanding of the factors affecting the release of allelopathic compounds and the mechanisms of their effects on target organisms.

Brassinosteroids (BRs) are considered to possess protective activity in plants exposed to various stresses. The present study was conducted to evaluate the effects of 24-epibrassinolide (EBL) on salt stressed summer squash cv. Eskandrani seedlings, whether it can alleviate the deleterious effects of salt stress in growing seedlings or not. For this, summer squash seeds were germinated in solidified half strength MS (Murashige and Skoog) medium supplemented with different concentrations and combinations of EBL (0, 5, 10 and 20 μM) and NaCl (0, 50, 100 and 150 mM). The different concentrations (5, 10, 20 μM) of EBL significantly increased germination percentage and seedling growth capacity and the greatest increase was observed at 10 μM EBL. EBL application significantly increased the contents of photosynthetic pigments, the relative water content and the uptake of K and Ca. However, the different concentrations (50, 100 and 150 mM) of NaCl significantly decreased the above-mentioned attributes. The different concentrations (50, 100 and 150 mM) of NaCl significantly increased the electrolyte leakage, the lipid peroxidation and the Na uptake, but the interaction between EBL and NaCl significantly decreased these parameters. The results of this study proved that the application of 24-epibrassinolide to growing squash seedlings under salt stress conditions reduced the deleterious effects of salt stress and increased the tolerance of seedlings to its detrimental effects.

The present study describes the elicitor effect of silver ion (Ag⁺) and biologically synthesized silver nanoparticles (AgNPs) to enhance the biomass accumulation and phenolic compound production as well as biological activities (antioxidant, antimicrobial and anticancer) in genetically transformed root (hairy root) cultures of Cucumis anguria. The biomass of hairy root cultures was significantly increased by AgNPs whereas decreased in Ag⁺ elicitation at 1 and 2 mg/L. AgNPs-elicited hairy roots produced a significantly higher amount of individual phenolic compounds (flavonols, hydroxycinnamic and hydroxybenzoic acids), total phenolic and flavonoid contents than Ag⁺-elicited hairy roots. Moreover, antioxidant, antimicrobial and anticancer activities were significantly higher following AgNPs-elicitation compared with that in Ag⁺-elicited hairy roots. We suggest that AgNPs could be an efficient elicitor in hairy root cultures to increase the phytochemical production.

This research was conducted in a greenhouse to evaluate the effects of exogenous application of salicylic acid (SA) (1 mM) and 6-benzylaminopurine (BAP) (50 μM) on physiological performance of faba bean (Vicia faba) under different levels of NaCl salinity (0, 4, 8 and 12 dS/m). The experiment was arranged as factorial on the bases of randomized complete block design in three replications. Leaf Na⁺ content, root and leaf soluble sugars, antioxidant enzymes activities such as catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and lipid peroxidation increased, but K⁺, K⁺/Na⁺ and membrane stability index (MSI) decreased as a result of salt stress. However, foliar sprays of BAP and particularly SA reduced Na⁺ content and lipid peroxidation, while enhanced the K⁺ content, K⁺/Na⁺, soluble sugars, antioxidant enzymes activities and MSI under different levels of salinity. It was, therefore, concluded that exogenous application of these growth regulators (GR) can considerably improve salt tolerance and physiological performance of faba bean.

T-2 toxin is primarily produced by Fusarium sp. abundant under temperate climatic conditions. Its main harmful effect is the inhibition of protein synthesis. Causing oxidative stress, it also promotes lipid peroxidation and changes plasma membrane phospholipid composition; this may lead to nervous system alterations. The aim of the present study was to examine whether a single dose of T-2 toxin administered at newborn age has any long-lasting effects on nervous system functions. Rat pups were treated on the first postnatal day with a single intraperitoneal dose of T-2 toxin (0.2 mg/bwkg). Body weight of treated pups was lower during the second and third week of life, compared to littermates; later, weight gain was recovered. At young adulthood, behavior was tested in the open field, and no difference was observed between treated and control rats. Field potential recordings from somatosensory cortex and hippocampus slices did not reveal any significant difference in neuronal network functions. In case of neocortical field EPSP, the shape was slightly different in treated pups. Long-term synaptic plasticity was also comparable in both groups. Seizure susceptibility of the slices was not different, either. In conclusion, T-2 toxin did not significantly affect basic nervous system functions at this dose.

The route of egg white transfer into the yolk and the mechanisms underlying the digestion of egg proteins are unexplored in the fertilized egg of the duck, Anas platyrhynchos domestica. Here, we investigated the route(s) of egg white transfer and we determined the type of activated proteases during duck embryo development. Initially, we tested the electrophoretic patterns of egg proteins throughout development. Then, we used lysozyme as a reference protein to follow egg white transfer and we measured its activity. After that, we determined the type of activated proteases by employing different types of protease inhibitors. Several presumptive egg white protein bands appeared in different egg compartments. Also, lysozyme activity was detected chronologically on day 15 in the extraembryonic fluid, on day 17 in the amniotic and intestinal fluids and on day 19 in the yolk. Furthermore, acidic aspartic proteases seemed to be activated at hatch in the intestine and late in development in the yolk. Our results suggest that the main route of egg white transfer into the yolk is through the amniotic cavity and intestinal lumen. Also, the transferred egg white and endogenous yolk proteins are probably digested by the activated acidic proteases in the intestine and yolk.

D-aspartate (D-Asp) modulates adult neural plasticity and embryonic brain development by promoting cell proliferation, survival and differentiation. Here, developmental changes of the excitatory amino acids (EAAs) L-Glu, L-Asp and D-Asp were determined during the first postembryonic days, a time window for early learning, in selected brain regions of domestic chickens after chiral separation and capillary electrophoresis. Extracellular concentration (ECC) of EAAs was measured in microdialysis samples from freely moving chicks. ECC of D-Asp (but not L-EAAs) decreased during the first week of age, with no considerable regional or learning-related variation. ECC of L-Asp and L-Glu (but not of D-Asp) were elevated in the mSt/Ac in response to a rewarding stimulus, suggesting importance of Asp-Glu co-release in synaptic plasticity of basal ganglia. Potassium-evoked release of D-Asp, with a protracted transient, was also demonstrated. D-Asp constitutes greater percentage of total aspartate in the extracellular space than in whole tissue extracts, thus the bulk of D-Asp detected in tissue appears in the extracellular space. Conversely, only a fraction of tissue L-EAAs can be detected in extracellular space. The lack of changes in tissue D-Asp following avoidance learning indicates a tonic, rather than phasic, mechanism in the neuromodulatory action of this amino acid.