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Silicon Differently Affects Apoplastic Binding of Excess Boron in Wheat and Sunflower Leaves
Get PDFMonocots and dicots differ in their boron (B) requirement, but also in their capacity to accumulate silicon (Si). Although an ameliorative effect of Si on B toxicity has been reported in various crops, differences among monocots and dicots are not clear, in particular in light of their ability to retain B in the leaf apoplast. In hydroponic experiments under controlled conditions, we studied the role of Si in the compartmentation of B within the leaves of wheat (Triticum vulgare L.) as a model of a high-Si monocot and sunflower (Helianthus annuus L.) as a model of a low-Si dicot, with the focus on the leaf apoplast. The stable isotopes 10B and 11B were used to investigate the dynamics of cell wall B binding capacity. In both crops, the application of Si did not affect B concentration in the root, but significantly decreased the B concentration in the leaves. However, the application of Si differently influenced the binding capacity of the leaf apoplast for excess B in wheat and sunflower. In wheat, whose capacity to retain B in the leaf cell walls is lower than in sunflower, the continuous supply of Si is crucial for an enhancement of high B tolerance in the shoot. On the other hand, the supply of Si did not contribute significantly in the extension of the B binding sites in sunflower leaves
Composite nanofibers electrospun from cerium, titanium, and zinc precursors
No full textNon-woven fibers were produced by sol-gel and electrospinning methods, from a solution containing cerium nitrate, zinc acetate, titanium isopropoxide, polyvinylpyrrolidone, acetic acid, ethanol, and water. The fibers were calcined at various temperatures ranging from 300 to 900 °C and were characterized using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, Energy Dispersive X-ray (EDX), Raman spectroscopy, Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Structural characterization revealed the fluorite nanocrystalline phase of ceria (CeO2) at all temperatures, the wurtzite zinc oxide (ZnO) phase in the 300–500 °C range, and a variety of zinc titanate phases (such as ZnTiO3, Zn2Ti3O8 and Zn2TiO4) at higher temperatures. Titania (TiO2) phases were not observed following calcination up to 900 °C. The average ceria nanocrystallite size increases with calcination temperature, as revealed by XRD and confirmed by the Phonon Confinement Model (PCM) of Raman spectra. The opposite trend is observed for the BET specific surface area of the nanofibers, where this value decreases with calcination temperatures above 400 °C. These nanofibers containing ceria and zinc titanates are potential candidates for photocatalytic applications
From promoting aggregation to enhancing obstruction: A negative feedback regulatory mechanism of alleviation of trivalent chromium toxicity by silicon in rice
No full textTrivalent chromium [Cr(III)] is a threat to the environment and crop production. Silicon (Si) has been shown to be effective in mitigating Cr(III) toxicity in rice. However, the mechanisms by which Si reduces Cr(III) uptake in rice are unclear. Herein, we hypothesized that the ability of Si to obstruct Cr(III) diffusion via apoplastic bypass is related to silicic acid polymerization, which may be affected by Cr(III) in rice roots. To test this hypothesis, we employed hydroponics experiments on rice (Oryza sativa L.) and utilized apoplastic bypass tracer techniques, as well as model simulations, to investigate 1) the effect of Si on Cr(III) toxicity and its obstruction capacity via apoplastic bypass, 2) the effect of Cr(III) on silicic acid polymerization, and 3) the relationship between the degree of silicic acid polymerization and its Cr(III) obstruction capacity. We found that Si reversed the damage caused by Cr(III) stress in rice. Si exerted an obstruction effect in the apoplast, significantly decreasing the share of Cr(III) uptake via the apoplastic bypass from 18% to 11%. Moreover, Cr(III) reduced silica particles' radii and increased Si concentration in roots. Modeling revealed that a 5-fold reduction in their radii decreased the diffusion of Cr(III) in apoplast by approximately 17%. We revealed that Cr(III) promoted silicic acid polymerization, resulting in the formation of a higher number of Si particles with a smaller radius in roots, which in turn increased the ability of Si to obstruct Cr(III) diffusion. This negative feedback regulatory mechanism is novel and crucially important for maintaining homeostasis in rice, unveiling the unique role of Si under Cr(III) ion stress and providing a theoretical basis for promoting the use of Si fertilizer in the field
Enhancement of weak ferromagnetism, exotic structure prediction and diverse electronic properties in holmium substituted multiferroic bismuth ferrite
No full textBismuth ferrite (BFO, BiFeO3), exhibiting both ferromagnetic and ferroelectric properties at room
temperature, is one of the most researched multiferroic materials with a growing number of technological applications. In the present study, using a combined theoretical–experimental approach, we have investigated the influence of Ho-doping on the structural, electronic and magnetic properties of BFO. Synthesis and structural XRD characterization of Bi1 xHoxFeO3 (x = 0.02, 0.05, and 0.10) nanopowders have been completed. After structure prediction of Ho-doped BiFeO3 using bond valence calculations (BVC), six most favorable candidates were found: a-, b-, g-, R-, T1, and T2. Furthermore, all structure candidates have been examined for different magnetic ordering using DFT calculations. The magnetic behavior of the synthesized materials was investigated using a SQUID magnetometer equipped with an oven. The plethora of magnetic and electronic properties of the Ho-doped BFO that our theoretical research predicted can open up rich possibilities for further investigation and eventual applications
Therapeutic potential of low-molecular weight lignin model polymer fractions for treating skin lesions in animals: a pilot study
No full textBacterial infections and resistance to antibiotics are increasingly severe problems. In recent years, Staphylococcus species
have emerged as important pathogens in animals and humans. Current therapeutic methods against these species have serious
disadvantages; therefore new agents with antibacterial potential, such as plant-based substances, are very important in
therapy. We report a pilot study with new method of fractioning the dehydrogenate polymer DHP obtained from coniferyl
alcohol and application of the low-MW fractions of 200–3000 Da for antibacterial activity in healing animal lesions. In
vivo experiments were conducted on the dogs having a skin lesion. Dogs were treated with the suspension containing the
low-MW DHP fractions as the active ingredient, in combination with alginate for 7 days. Cytological smears and microbiological
analyses of the affected area were performed. Staphylococcus spp. was isolated from lesions in all dogs from
our research. The results show that the low-MW DHP suspension in alginate promotes skin healing and reduction of the
infection of the lesions in the affected animals. Pharmaceutical composition containing the low-MW DHP fractions exerts
a soothing effect on the subject in wound treatment. Reduction in the number of bacteria by 30% and more were noticed
in 6 dogs, while in 4 dogs this percentage is above 50%. No side effects were noticed. Synthesized lignin oligomers may
have a significant place as antimicrobial and skin healing agents, especially since an increasing number of multidrugresistant
staphylococci are found on the skin lesions in animals
Electrical and sensing properties of indium-doped barium cerate
Get PDFSystematic analysis of electrical characteristics of BaCe0.75In0.25O3-δ (BCI25) sintered sample was performed in a
dry and a wet argon atmosphere in the 250 ◦C–700 ◦C temperature range. The water vapor sensing properties of
BCI25 porous film and its response and recovery times were investigated under different conditions of temperature
and water vapor concentration. The 30 μm thick film obtained from the powder calcined at 1050 ◦C
exhibited sensitivity comparable to that of the sintered sample with a significantly shorter response and recovery
times. While the sensitivity of the film gradually decreased with a decrease in partial pressure of water vapor (p
(H2O)), a noticeable sensitivity was still observed at p(H2O) of 200 Pa. Decrease in conductivity depended
logarithmically on the partial pressure of water with the slope of 0.52 that is close to the theoretical value. After
several cycles, the reusability test proved an almost unchanged ratio between the impedance value in the dry and
the wet Ar atmosphere (p(H2O) = 2.34 kPa), which implied that BCI25, having good stability and sensitivity, is a
promising high-temperature humidity sensor
Synthesis and characterization of luminescent Cu2+–doped fluorapatite nanocrystals as potential broad–spectrum antimicrobial agents
No full textNanomaterials based on metal–doped fluorapatite (FAP) have attracted considerable interest as potential
next–generation antimicrobial agents. In this study, Cu2+–doped FAP nanocrystals have been successfully synthesized
by a neutralization method at room temperature. Their structural, optical, antimicrobial, and hemcompatible
properties have been investigated. XRD, FTIR, FESEM, and N2 adsorption–desorption studies indicate
the formation of single–phase FAP mesoporous nanopowders, composed of rod–like particles. TEM images
confirmed the formation of nanorodes with a length of 60 nm and a width of about 18 nm. Rietveld analysis
shows that the Cu2+ ions preferentially substitute Ca2 (6 h) sites in the hexagonal fluorapatite crystal structure.
Fluorescence spectroscopy accompanied by MCR–ALS method confirms substitution of Cu2+ ions in FAP crystal
lattice with extracting additional d–d band transition at green color from FAP broadband self–activated luminescence
in violet–blue color. Antimicrobial studies conducted on Staphylococcus aureus, Escherichia coli and
Micrococcus lysodeikticus showed that FAP nanopowder with the highest Cu2+ content have strong bacteriostatic
action on Staphylococcus aureus bacterial strain in mediums containing nutrition matters. In addition, this sample
in comparison to pure FAP achieved a high percentage of relative reduction of bacterial population for all three
species, being >90% in most cases. Fungistatic action is noticed too, throwgh the slowing down mycelium
growth of fungus Aspergillus niger, Aspergillus flavus and Penicillium roqueforti and reduction of sporulation of
Aspergillus niger species. Cu2+–doped FAP nanocrystals shows a synergistic antimicrobial effect with Cu2+ and F�����
ions. Concerning the potential biomedical applications, the hemolysis ratios of the Cu2+–doped FAP samples
were below 5%. The obtained results pointed out the possible use of the synthesized nanocrystals as broad–
spectrum antimicrobial agents for various biomedical and health care preparations
Slight cooling during growth induced changes in filamentous fungi hypha mitochondrial morphology
Get PDFAdaptive changes in mitochondrial morphology are associated with changes in the mitochondrial function and metabolic fitness of eukaryotic cells. We previously described in young hyphae of the filamentous fungus Phycomyces blakesleeanus a dramatic effect of an increase in ambient temperature during growth: a 3°C warmer environment compared with a control temperature of 22°C resulted in the appearance of long elongated (“tubular”) mitochondria accompanied by an increase in lipid droplet density. Here, we examined how cooler ambient temperature (18°C) during growth affects mitochondrial morphology in P. blakesleeanus compared with the control grown at 22°C. We used two-photon fluorescence imaging (TPEF) of live hyphae stained with the vital mitochondrial dye rhodamine 123. Extraction of relevant parameters (number, size, and shape of mitochondria) from TPEF images was performed using the Ilastik machine learning-based software. The suitability of the Ilastik analysis was compared with the Particle Analysis (ImageJ). Cold treatment resulted in the appearance of tubular mitochondrial morphology that was absent in the control group. Tubular mitochondrial morphology appears to be an adaptive feature that occurs in both warmer and colder conditions and is likely part of the stress response
Gamma-glutamyltransferase-associated glycoprotein patterns in human seminal plasma of normozoospermic men: a new aspect of biomarker heterogeneity
Get PDFBackground. Gamma-glutamyltransferase (GGT) is a well-known laboratory biomarker. In spite of high concentration
and the possible biomedical importance of estimating GGT in human seminal plasma (hSP), it has not been widely
explored in reproductive physiology. This study aimed to complement existing data on its diversity, previously obtained
on seminal extracellular vesicles, by analyzing matched soluble fraction of hSP. The GGT-associated patterns of
selected glycoproteins were analyzed in order to establish an adjunct referent parameter for differentiation between
known high molecular mass forms of GGT. Getting insight into distinct GGT-associated glycoprotein patterns should
contribute to define them together as possible multimarkers.
Methods. GGT forms in soluble, membrane-free-fraction isolated form hSP of normozoospermic men were analyzed
using gel filtration and lectin blotting using WGA (wheat germ agglutinin) and Con A (concanavalin A).
Results. Widely distributed GGT (with two to three partially resolved peaks), which may correspond to high molecular
mass aggregates, were detected. GGT-associated patterns of selected glycoproteins (at position of big, medium, and
small-GGT) all comprised high molecular mass WGA-reactive smears, but differed in the presence of Con A-reactive
glycans, as well as mucin-associated antigens CA19-9 and CA125.
Conclusions. GGT contributes to several molecular patterns that differ between the soluble and extracellular vesicle
fractions of hSP. Their glycobiochemical heterogeneity is due to difference in the presence of distinct sialylated and mannosylated
glycans. Moreover, GGT-associated glycoprotein patterns differentiate between high molecular mass forms
of GGT in the soluble fraction of hSP. They hold promise as possible targets for increasing biomarker potential of GGT
Diet Analysis of the Amur Sleeper (Perccottus glenii) from the Danube River Drainage Channel (Serbia)
Get PDFThe stomach content of 277 Amur sleeper individuals has been analyzed to present its
feeding habits. Fish were sampled using electrofishing from July to November 2017 in
the Danube River drainage channel near Veliko Gradište (Serbia). Fish age was
estimated by otoliths examination. Ingested prey organisms were identified to the
lowest reliable taxonomic level. The biotic indices: vacuity index (VI), frequency of
occurrence (F), abundance (Cn), index of importance (PV), Shannon’s diversity index
(H’), and equitability index (Eh) were calculated. A total of 18 prey categories and 1144
individual prey were identified in the fish diet, dominantly aquatic macroinvertebrates.
There were no significant difference in diet composition between sampling months as
well as 0+, 1+, and 2+ age groups (both 3+ and 4+ had one individual). Only eight
individuals were found with empty intestines, thus VI was low (2.9). In average, each
fish had 4.1 prey items in their intestines. For whole sample, H′ was 1.84 and Eh was
0.64. Trichoptera, Ephemeroptera, and Gastropoda were the most frequent,dominant, and abundant. The greatest diversity of prey items was recorded for fish sampled in October as well as for 2+ individuals, and the lowest for fish from August and 0+ individuals