Effect of manganese on antioxidant activity in maize

Manganese (Mn) is an essential element for plant growth. For metabolic function, Mn2+ is required at low concentrations, but Mn2+ excess can change the activity of various enzymes and interfere with the absorption and translocation of some minerals such as Ca, Mg, Fe, and P. Mn availability to the plants depends on pH of the growth medium and on root exudates for Mn chelation or reduction. The main aim of this research was to investigate the effect of Mn2+ on the main parameters of secondary metabolism: total phenolic content (TPC) and total antioxidative activity (TAA) in maize (Zea mays L.) shoots and roots. Maize was chosen as agricultural species important for human and animal nutrition, and a simply cultivated plant. Maize seeds (inbred line Va35) were germinated in distilled water and then transferred into the hydroponic (KNOP/2) growth solution. Mn2+ was applied in two different concentrations (5 and 100 μM) by adding MnSO4 into the hydroponic solution. After 7 days (December 2021) of growing under 8/16h photoperiod, the leaves and roots were collected. The TPC was measured according to Folin-Ciocalteu’s spectrophotometric procedure, while TAA was determined by ABTS/HRP assay. The results showed that TAA was significantly decreased only in maize roots after the treatment with 5 μM Mn2+, while higher Mn2+ concentration (100 μM) did not change TAA in maize roots. TAA in shoots and TPC in both parts of maize was unchanged. Finding that 5 μM of Mn2+ have decreasing effect on maize antioxidative activity without harming plants indicates that lower concentration can be more toxic due to: 1. plants excreting an excess of Mn2+ into the environment after the treatment with high Mn2+ concentration and 2. Mn can affect the metabolism of small molecules (enzymes or phytochelatins) binding for them and decreasing the total ROS scavenging activity

Kinetic parameters for thermal inactivation of soluble peroxidase from needles of Serbian spruce Picea omorika (Pancic) Purkyne

Thermal inactivation of peroxidase (POD) in an extract of Picea omorika (Pancic) Purkyne needles initiated by heat treatment was studied. This is the first study of this kind on a conifer species. Non-linear regression analysis was applied on the inactivation rate data, combining Mitscherlich and Arrhenius equations, treating time and temperature simultaneously as explaining variables. We determined the inactivation rate constant k, the Arrhenius energy of inactivation E and the remaining activity C-min for the crude extract and for separated acidic and basic enzyme fractions, as well as for individual isoenzymes separated electrophoretically. A comparison of inactivation parameters for acidic and basic fractions shows that the thermal inactivation rate of the basic fraction is higher. The obtained value of inactivation energy for crude extract was between the values for acidic and basic isoenzyme fractions. One of the three analysed individual isoenzymes was characterised by a lower inactivation rate constant and higher inactivation energy. Another isoenzyme showed considerably higher level of remaining activity compared to the others, which identified it as the most resistant to high temperatures. The acquired values of Arrhenius energy of inactivation for POD in crude extract were intermediate, considering a range of POD values for various other plant species

Activities of antioxidant systems during germination of Chenopodium rubrum seeds

The activities of superoxide-dismutase (SOD), catalase (CAT) and peroxidase (POD), and concentrations of glutathione and ascorbate have been studied during the first stages of germination in Chenopodium rubrum L. seeds. The highest CAT and SOD activity was found prior to radicle Protrusion, while POD activity was maximal at the time of radicle protrusion and seedling development, new POD isozymes simultaneously appearing. The concentrations of total, reduced and oxidized glutathione showed similar changes during germination, the highest values being detected at the time of radicle protrusion. Ascorbic acid was present in the seeds in a detectable concentration only at the time preceding radicle protrusion, while its oxidized form dehydroascorbic acid was detected during the whole germination period studied. Gibberellic acid (GA(3), 160 muM) had no effect on germination percentage, but in presence of GA(3), SOD and CAT activity notably increased prior to radicle protrusion, and oxidized concentration decreased in further germination

Imaging FTIR microscopy – technique for rapid screening of plant cell walls

It has been shown that xylan is oriented in parallel to the cellulose and more or less parallel to the axis of a cell wall, in isolated CW fragments from maize leaves. There was also a clear indication of lignin orientation parallel to the longitudinal CW axis. This means that all of these components show strong anisotropic behaviour and organisation

Razlikovanje komercijalnih uzoraka vina korišćenjem fluorescentne spektroskopije i multivarijacione analize

Steady state fluorescence spectroscopy in combination with Multivariate Curve Resolution - Alternating Least Squares (MCR-ALS) for spectral analysis has been applied to differentiate commercial samples of wines available on the market. We have chosen the wine trade marks from the two Serbian producers that contain only one wine type, since such approach is a starting step for further analyses of the more complex samples containing different wine types. We also studied changes of the emission spectra of these samples during seven days after opening of the wine bottle. The emission spectra were recorded in the wavelength range 275 - 500 nm, after excitation in the range 255 - 300 nm. The spectra of the wine samples obtained from the same producer are very similar, i.e. contain the same components in the similar ratios. The changes of spectral components at 315 nm and 430 nm were the basis for differentiation of the wine samples from the two producers, as well as for estimation of the wine stability in time after the bottle opening. The results indicate that this may be a useful approach in fingerprinting wines from various producers, as well as in screening the stability of wine.Fluorescentna spektroskopija u kombinaciji sa metodom Multivarijaciona Rezolucija Krivih - Naizmenični Najmanji Kvadrati (Multivariate Curve Resolution - Alternating Least Squares, MCR-ALS), je primenjena za razlikovanje komercijalnih uzoraka vina dostupnih na tržištu. Odabrali smo trgovačke marke vina od dva srpska proizvođača koje sadrže samo jednu vrstu vina, jer je ovakav pristup početni korak za kasnije analize složenijih uzoraka koji sadrže različite vrste vina. Takođe smo proučavali promene emisionih spektara ovih uzoraka u toku sedam dana posle otvaranja boce. Emisioni spektri su mereni u opsegu talasnih dužina 275 - 500 nm, posle pobuđivanja u opsegu 255 - 300 nm. Spektri uzoraka vina od istog proizvođača su veoma slični, to jest sadrže iste komponente u sličnom međusobnom odnosu. Promene komponenata spektara na 315 nm i 430 nm bile su osnova za razlikovanje uzoraka vina od dva proizvođača, kao i za procenu stabilnosti vina u vremenu posle otvaranja boce. Rezultati ukazuju da ovo može biti koristan pristup u razlikovanju vina od različitih proizvođača, kao i u praćenju stabilnosti sastava vina

The methods for nanoceria’s coating in order to improve its solubility

CeO2 (nanoceria) is the most important rare-earth oxide and potent free radical scavenger, due to coexistence of Ce3+ and Ce4+ ions and formation of oxygen vacancies on its surface. These nanoparticles can collect reactive oxygen species (ROS) and protect healthy cells from oxidative stress, but they also show cytotoxicity. This dual behavior of nanoceria represents a great pharmacological potential, such as improving the treatment of cancers, drug delivery and catalysis. We established the method for synthesizing these nanoparticles, which was particularly challenging because of their low solubility. To facilitate nanoparticle’s entry into the cells, we further coated these nanoparticles with the addition of carbohydrate (glucose, levan or pullulan) in the reaction mixture during and after the synthesis of nanoceria. We investigated by which of two applied methods of synthesis gave more soluble ceria nanoparticles

Carbohydrate-coated cerium oxide nanoparticles affect the germination of Sinapis alba and Chenopodium rubrum seeds through the generations

The various applications of cerium oxide nanoparticles (nCeO2), one of the most produced metal oxide nanoparticles, could affect environmental health due to accumulation of uncoated and coated nCeO2 with increased suspension stability. The trans-generational effects on seed characteristics are important components of the life histories of plants representing the pathway from adult to offspring that completes the life cycle. The effects of carbohydrate-coated nCeO2 on the plant seeds through the generations are still unknown. The main aim of this study was to investigate the effect of the treatment of maternal Sinapis alba and Chenopodium rubrum plants with 200 mg/L of uncoated (CeO2) and glucose-, levan-, or pullulan coated nCeO2 (G-, L-, оr P-CeO2) on germination of three generations of seeds. Sinapis alba was selected as a hyperaccumulator of heavy metals, while Chenopodium rubrum was selected as a short-day plant and weed. In Sinapis alba, the results of germination on the 4th day revealed increased germination after the treatment with CeO2 and L-CeO2 nanoparticles in zero generation and after all nCeO2 treatments in the 1st and 2nd generation of seeds. In Chenopodium rubrum, there were no changes after the treatments. It can be concluded that trans-generational effects of the different nCeO2 treatments persist to at least the second generation in seeds. Compared to the same generation control, the 2nd generation of seeds showed the highest sensitivity. The coated nCeO2 were more effective than the uncoated ones. Enhanced germination in three generations of S. alba seeds recommends nCeO2 for application in seed-priming

Antioxidant activity estimation of inner and outer seed fractions of the legumes Vigna radiata L. and Glycine max L.

Legumes have multiple functions in sustainable agriculture, but also are a favourable ingredient of functional nutrition. Antioxidants in legumes have several beneficial physiological properties and provide protection against chronic diseases. In this study, we compared the antioxidant activities of the seed fractions (outer and inner) for two different legumes: mung bean (Vigna radiata L.) and soybean (Glycine max L). The antioxidant activity was estimated using a modified DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay in a 96-well microplate. We showed that mung bean hulls possessed significantly higher (p<0.05) DPPH free radical scavenging activity (80.80 % ± 0.19) compared to their inner fraction (10.94 % ± 0.23), as well as to both fractions of the soybean. On the other hand, the soybean seeds' inner fractions (21.00 % ± 0.32) exhibited a significantly (p<0.05) higher activity than the hulls (8.78 % ± 0.71) and the inner fraction of the mung bean. The obtained results indicated that in each of the two analysed legume species, inner and outer seed fractions exhibited different antioxidant activities regarding to the elimination of the free radicals. The obtained results indicate that antioxidant capacity may be a useful indicator in the estimation of the quality of legume seeds as food and feed

Characterization of colored maize seed fractions using fluorescence spectroscopy and multivariate analysis

In the present study, we used the Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) algorithm to analyse the excitation-emission matrices (EEM's) of various cultivars of colored maize (Zea mays L.) seeds and its fractions. The EEMs were recorded as a set, with the excitation ranging from 280 nm to 380 nm and the emission spectra ranging from 300 nm to 550 nm. The MCR-ALS analysis yielded two major fluorescence components for all of the analysed samples. Both position and shape of the component 1 (C1), varied among the samples. On the other hand, the position and shape were similar for the component 2 (C2). C1 could be used as a marker for discrimination of colored seeds and their fractions. The observed variations in C1 between the analysed seeds, based on the presence of their individual fluorophores, can be assigned to anthocyanins, proteins, and phenolics. In conclusion, the MCR-ALS analysis of the seed emission spectra have a great potential for the rapid and non-expensive characterization of various cultivars of colored seeds

Visualization of artificial lignin supramolecular structures

In this paper we are presenting the results of our environmental scanning electron microscopy (ESEM) investigation of the lignin model compound-enzymatically polymerized coniferyl alcohol, also known as dehydrogenate polymer (DHP). The goals of this study were to visualize the supramolecular organization of DHP polymer on various substrates, namely graphite, mica, and glass, and to explore the influence of substrate surface properties and associated collective phenomena on the lignin self-assembled supramolecular structure. Based on results obtained with ESEM, combined with previously published results based on scanning tunneling microscopy (STM) and electron spin resonance (ESR) technique, we looked at Lignin structure ranging from a monomer on a fraction of nanometer scale to a large aggregate on a fraction of millimeter scale. therefore using six orders of magnitude range of size. Herein, we are presenting evidence that there are at least four different levels of the supramolecular structure of lignin, and that its supramolecular organization is well dependent on the substrate surface characteristics, such as hydrophobicity, delocalized orbitals, and surface-free entry