The relationship of physicochemical properties and structure to the antioxidative activity of free amino acids in the aqueous Fenton system

Iron is essential for plant growth, metabolism of mitochondria and chloroplasts, and a wide assortment of enzymes. However, it is also involved in Fenton reaction that generates hydroxyl radical (HO•), the most reactive species in plants. The aim of our study was to examine the effects of amino acids on HO• production. The rank order according to antioxidative activity (AA) of amino acids in Fenton system was: Trp > Phe, Leu > Ile > His > Arg > Val > Lys, Tyr, Pro > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Sulfur-containing amino acids generated different secondary reactive products, which were discriminated by EPR spin-trapping spectroscopy. AA showed positive correlation with hydrophobicity and negative correlation with polarity. HO•provoked oxidation of amino acids was strongly positively affected by hydrophobic hydration. Group contribution method showed that the reactivity of amino acids with HO• is defined by the properties of side-chains (the contribution of NH3+CHCOO− group and antioxidative activity of Gly were next to zero). Our results might shed a new light on the role of iron in the regulation of free amino acids pool and on protein oxidation in plants. According to our findings, native proteins (with exposed polar residues) might not be particularly susceptible to oxidation by HO•. But once a protein is damaged and partially denatured it exposes hydrophobic side-chains and might become a likely target for HO•, thus potentially acquiring an antioxidative role. Further research on change of redox properties of proteins with denaturation is warranted

Fluorescence spectroscopy and multispectral imaging for fingerprinting of aflatoxin‑B1 contaminated (Zea mays L.) seeds: a preliminary study

Cereal seeds safety may be compromised by the presence of toxic contaminants, such as aflatoxins. Besides being carcinogenic, they have other adverse health effects on humans and animals. In this preliminary study, we used two non‑invasive optical techniques, optical fiber fluorescence spectroscopy and multispectral imaging (MSI), for discrimination of maize seeds naturally contaminated with aflatoxin B 1 (AFB 1 ) from the uncontaminated seeds. The AFB 1‑contaminated seeds exhibited a red shift of the emission maximum position compared to the control samples. Using linear discrimination analysis to analyse fluorescence data, classification accuracy of 100% was obtained to discriminate uncontaminated and AFB 1‑contaminated seeds. The MSI analysis combined with a normalized canonical discriminant analysis, provided spectral and spatial patterns of the analysed seeds. The AFB 1‑contaminated seeds showed a 7.9 to 9.6‑fold increase in the seed reflectance in the VIS region, and 10.4 and 12.2‑fold increase in the NIR spectral region, compared with the uncontaminated seeds. Thus the MSI method classified successfully contaminated from uncontaminated seeds with high accuracy. The results may have an impact on development of spectroscopic non‑invasive methods for detection of AFs presence in seeds, providing valuable information for the assessment of seed adulteration in the field of food forensics and food safety

Sesquiterpene lactones content in lettuce cultivars affected by microbiological fertilisers and seasons

The principal sesquiterpene lactones (lactucin, lactucopicrin, and its dihydro forms), known as contributors to bitter taste, were measured in green and red coloured lettuce using Ultra-performance liquid chromatography. Six lettuce cultivars (‘Kiribati’, ‘Murai’, ‘Aquino’, ‘Gaugin’, ‘Aleppo’ and ‘Carmesi’) were grown in a greenhouse experiment using microbiological fertilisers (EM Aktiv, Vital Tricho, and their combination) during three successive growing seasons (autumn, winter, and spring). The major sesquiterpene lactone was lactucopicrin with the highest level found in cultivar ‘Carmesi’ (0.65 mg/g dry weight) in autumn with the combination of fertilisers. The concentrations of lactucin, dihydrolactucin and dihydrolactucopicrin ranged from 0.001-0.085, 0.003-0.015, and 0.001-0.056 mg/g dry weight, respectively, and were not found in all lettuce samples. Generally, red cultivars showed higher content of lactones compared to green. Application of Vital Tricho and the combination of fertilisers led to an increased level of lactucopicrin, in some cultivars, in the range of 77-800% compared to unfertilised plants. Higher levels of lactucopicrin were found in the autumn trial compared to spring and winter. The present study suggests that genotype, fertilisers and season jointly affected the quantity of sesquiterpene lactones with emphasis on Vital Tricho, and/or the combination of fertilisers

Correction to: Parenchyma cell wall structure in twining stem of Dioscorea balcanica (vol 24, pg 4653, 2017)

In the original publication of the article, one of the project numbers was omitted in the Acknowledgments. The correct version is provided below.Original publication: [http://cer.ihtm.bg.ac.rs/handle/123456789/2090

Direct selection parameter estimates and path coefficient analysis for grain yield and quantitative traits in maize (Zea mays l.)

The study was carried out at the Maize Research Institute “Zemun Polje”, Belgrade, Serbia during 2021 growing season in three location. Six inbred lines were crossed according to complete diallel method. In this way 15 hybrids and 15 reciprocal combinations were obtained. Hybrid and reciprocal combinations derived from these parental components were used in this paper. The present study was carried out to study the variability, broad-sense heritability (H2 bs), genetic advance (GA), correlation among traits, genotypic and phenotypic path analysis among grain yield and its components. The results indicated that the genotypes were significantly different for all traits. For all traits, the phenotypic coefficient of variation was higher than the genotypic coefficient of variation. The highest heritability was found in 1000 kernel weight, followed by grain yield, ear diameter and anthesis-silking interval (ASI). In our study Genetic Advance over Mean (GAM) for the traits ranged from lowest value (9.739%) for cob diameter to the highest value (90.579%) for anthesis-silking interval. According to results of path analysis, the trait 1000 kernel weight with the value of 0.365 has the strongest direct positive effect on grain yield. Positive direct effects on grain yield were also observed for ear length (0.202), ear diameter (0.248) and number of rows per ear (0.076), while negative direct effects were observed for cob diameter (-0.057). The trait 1000 kernel weight had the highest indirect positive effects on grain yield via ear diameter (0.232). The cob diameter had highest negative indirect effect on grain yield via ear diameter (-0.048). Coefficient of multiple determinations (R2 ) had a value of 0.428. This indicated the important role of additive gene effect in the inheritance of these traits and could be improved through simple selection

Viability assessment of maize (Zea mays L.) seeds contaminated with aflatoxin using fluorescence spectroscopy

Maize seeds are a primary source of nourishment and their viability is a critical consideration to ensure a reasonably high harvest and seed quality. In this work, we study the effect of aflatoxin induced stress on the seed viability concerning the germination, as well as the estimation on the impact on the viability using fluorescence spectroscopy. Our results showed that the contaminated seeds exhibit significant decreases in the percent of germination, even at low levels, if compared to the uncontaminated seeds (P < 0.05). Furthermore, the fluorescence ratio of 453/680 and 680/751, could be used for the rapid screening of the viability of the maize seeds

The effect of microbiological fertilizers and season on the vitamin C content in lettuce leaves

Салата је једногодишња врста која припада групи лиснатог поврћа, богата минералима, антиоксидантима, витаминима. Циљ истраживања био је да се утврди утицај генотипа, микробиолошких ђубрива и сезоне на садржај витамина Ц у старим и младим листовима. Три зелене сорте (′Kiribati′, ′Aleppo′, ′Aquino′) су гајене у пластенику током три узастопне сезоне уз примену микробиолошких ђубрива (EМ Aktiv, Vital Tricho и њихова комбинација). Највећи садржај витамина Ц у старим и младим листовима показала је сорта ′Aleppo′ у јесен (8,93 mg/100g; 12,36 mg/100g). Микробиолошка ђубрива допринела су повећању садржаја витамина Ц код сорти ′Aleppo′ у пролеће и ′Aquino′ у јесен и зиму.Lettuce is an annual, green leafy vegetable, rich in minerals, antioxidants and vitamins. The aim of this study was to examine the effect of genotypes, microbiological fertilizers and seasons on vitamin C content in outer and inner leaves. Three green cultivars (′Kiribati′, ′Aleppo′, ′Aquino′) were grown in a greenhouse during three successive seasons with application of microbiological fertilizers (EМ Aktiv, Vital Tricho and combination). The highest vitamin C content in both leaves showed cultivar ′Aleppo′ in autumn (8,93 mg/100g; 12,36 mg/100g FW). Microbiological fertilizers increased level of vitamin C in cultivar ′Aleppo′ in spring and ′Aquino′ in autumn and winter

Influence of Pr3+ and CO32- Ions Coupled Substitution on Structural, Optical and Antibacterial Properties of Fluorapatite Nanopowders Obtained by Precipitation

Coupled substitution of fluorapatite (FAP) crystal lattice plays an important role in the engineering of optically active nanomaterials. Uniform fluorapatite nanopowders doped with praseodymium (Pr3+) and carbonate (CO32-) ions have been successfully synthesized by precipitation method under room temperature (25 degrees C). The structural, morphological, chemical and optical properties of monophase material were characterized by X-ray diffraction (XRD), Fourier Transform Infrared and Far Infrared Spectroscopy (FTIR and FIR, respectively), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS), Transmission Electron Microscopy (TEM) and Photoluminescence Spectroscopy (PL). Coupled substitution of FAP crystal lattice with Pr3+ and CO32- reduces the crystallite size with a constant c/a ratio of 1.72. FTIR study showed that synthesized nanopowders were AB-type CO32- substitution, and FIR study revealed new Pr-O vibrations. TEM analysis was found that synthesized nanopowders were composed of irregular spheres in the nanometer range. The fluorescence of FAP nanoparticles was in the violet-blue region of the visible part of the spectrum. When Pr3+ was doped in a lattice, the violet-blue emission becomes sharper due to reabsorption. MCR-ALS analyses of fluorescence spectra indicated the shift of the maximum to the blue color with the increase in the concentration of Pr3+ ions. Additionally, luminescent nanopowders demonstrated significant antibacterial activity against Escherichia coli. As the obtained nanoparticles showed a good absorption of ultraviolet A light and reabsorption of blue-green luminescence, they are suitable for further development of optically active nanomaterials for light filtering. Optically active PrCFAP nanopowders with antibacterial properties may be promising additives for the development of multifunctional cosmetic and health care products