Decavanadate-Bearing Guanidine Derivatives Developed as Antimicrobial and Antitumor Species

To obtain biologically active species, a series of decavanadates (Hpbg)4[H2V10O28]·6H2O (1) (Htbg)4[H2V10O28]·6H2O; (2) (Hgnd)2(Hgnu)4[V10O28]; (3) (Hgnu)6[V10O28]·2H2O; and (4) (pbg = 1-phenyl biguanide, tbg = 1-(o-tolyl)biguanide, gnd = guanidine, and gnu = guanylurea) were synthesized and characterized by several spectroscopic techniques (IR, UV-Vis, and EPR) as well as by single crystal X-ray diffraction. Compound (1) crystallizes in space group P-1 while (3) and (4) adopt the same centrosymmetric space group P21/n. The unusual signal identified by EPR spectroscopy was assigned to a charge-transfer π(O)→d(V) process. Both stability in solution and reactivity towards reactive oxygen species (O2- and OH·) were screened through EPR signal modification. All compounds inhibited the development of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis bacterial strains in a planktonic state at a micromolar level, the most active being compound (3). However, the experiments conducted at a minimal inhibitory concentration (MIC) indicated that the compounds do not disrupt the biofilm produced by these bacterial strains. The cytotoxicity assayed against A375 human melanoma cells and BJ human fibroblasts by testing the viability, lactate dehydrogenase, and nitric oxide levels indicated compound (1) as the most active in tumor cells.

Effect of the Preparation Method on the Properties of Eugenol-Doped Titanium Dioxide (TiO2) Sol-Gel Coating on Titanium (Ti) Substrates

The focus of this study was the preparation of sol-gel titanium dioxide (TiO2) coatings, by the dip-coating technique, on Ti6Al4V (TiGr5) and specific Ti implant substrates. In order to confer antibacterial properties to the layers, Eugenol was introduced in the coatings in two separate ways: firstly by introducing the Eugenol in the sol (Eug-TiO2), and secondly by impregnating into the already deposed TiO2 coating (TiO2/Eug). Optimization of Eugenol concentration as well as long term were performed in orderboth short- and long-term Eugenol concentration was performed to investigate the prepared samples thoroughly. The samples were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PDP). To investigate their resistance against Gram-negative Escherichia coli bacteria, microbiological analysis was performed on coatings prepared on glass substrates. Structural studies (FT-IR analysis, Raman spectroscopy) were performed to confirm Eugenol-TiO2 interactions. Coating thicknesses and adhesion were also determined for all samples. The results show that Eug-TiO2 presented with improved anticorrosive effects and significant antibacterial properties, compared to the other investigated samples.

The Effect of Functionalized Multiwall Carbon Nanotubes with Fe and Mn Oxides on Lactuca sativa L

The aim of this work was to evaluate the effect of six nanomaterials, namely CNT-COOH, CNT-MnO2, CNT-Fe3O4, CNT-MnO2-Fe3O4, MnO2, and Fe3O4 on lettuceTo determine the impact of nanomaterials on lettuce, the results obtained were compared with those for the control plant, grown in the same conditions of light, temperature, and humidity but without the addition of nanomaterial. The study found that the content of bioactive compounds and the antioxidant capacity varied in the treated plants compared to the control ones, depending on the nanomaterial. The use of CNTs functionalized with metal oxides increases the elemental concentration of lettuce leaves for the majority of the elements. On the contrary, metal oxide nanoparticles and CNT functionalized with carboxyl groups induce a decrease in the concentration of many elements. Soil amending with MnO2 affects the content of more than ten elements in leaves. Simultaneous application of CNT and MnO2 stimulates the elemental translocation of all elements from roots to leaves, but the simultaneous use of CNT and Fe3O4 leads to the most intense translocation compared to the control other than Mo.

Phytochemical Characterization and Antimicrobial Activity of Several Allium Extracts

Microbial infections affect both the human population and animals. The appearance of more and more microbial strains resistant to classical treatments led to the need to develop new treatments. Allium plants are known for their antimicrobial properties due to their high content of thiosulfinates, especially allicin, polyphenols or flavonoids. The hydroalcoholic extracts of six Allium species obtained by cold percolation were analyzed regarding their phytochemical compounds and antimicrobial activity. Among the six extracts, Allium sativum L. and Allium ursinum L. have similar contents of thiosulfinates (approx. 300 μg allicin equivalents/g), and the contents of polyphenols and flavonoids were different between the tested species. The HPLC-DAD method was used to detail the phytochemical composition of species rich in thiosulfinates. A. sativum is richer in allicin (280 μg/g) than A. ursinum (130 μg/g). The antimicrobial activity of A. sativum and A. ursinum extracts against Escherichia coli, Staphylococcus aureus, Candida albicans and Candida parapsilosis can be correlated with the presence of large amounts of thiosulfinates. Both extracts have shown results against Candida species (inhibition zones of 20-35 mm) and against Gram-positive bacteria, Staphylococcus aureus (inhibition zones of 15-25 mm). These results demonstrate the antimicrobial effect of the extracts and suggest their use as an adjuvant treatment for microbial infections.

Mo-LDH-GO Hybrid Catalysts for Indigo Carmine Advanced Oxidation

This paper is focused on the utilization of hybrid catalysts obtained from layered double hydroxides containing molybdate as the compensation anion (Mo-LDH) and graphene oxide (GO) in advanced oxidation using environmentally friendly H₂O₂ as the oxidation agent for the removal of indigo carmine dye (IC) from wastewaters at 25 °C using 1 wt.% catalyst in the reaction mixture. Five samples of Mo-LDH-GO composites containing 5, 10, 15, 20, and 25 wt% GO labeled as HTMo-xGO (where HT is the abbreviation used for Mg/Al in the brucite type layer of the LDH and x stands for the concentration of GO) have been synthesized by coprecipitation at pH 10 and characterized by XRD, SEM, Raman, and ATR-FTIR spectroscopy, determination of the acid and base sites, and textural analysis by nitrogen adsorption/desorption. The XRD analysis confirmed the layered structure of the HTMo-xGO composites and GO incorporation in all samples has been proved by Raman spectroscopy. The most efficient catalyst was found to be the catalyst that contained 20%wt. GO, which allowed the removal of IC to reach 96.6%. The results of the catalytic tests indicated a strong correlation between catalytic activity and textural properties as well as the basicity of the catalysts.

The Antibacterial Properties of Nanocomposites Based on Carbon Nanotubes and Metal Oxides Functionalized with Azithromycin and Ciprofloxacin

Different microorganisms are present in nature, some of which are assumed to be hazardous to the human body. It is crucial to control their continuing growth to improve human life. Nanomaterial surface functionalization represents a current topic in continuous evolution that supports the development of new materials with multiple applications in biology, medicine, and the environment. This study focused on the antibacterial activity of different nanocomposites based on functionalized multi-walled carbon nanotubes against four common bacterial strains. Two metal oxides (CuO and NiO) and two antibiotics (azithromycin and ciprofloxacin) were selected for the present study to obtain the following nanocomposites: MWCNT-COOH/Antibiotic, MWCNT-COOH/Fe₃O₄/Antibiotic, and MWCNT-COOH/Fe₃O₄/MO/Antibiotic. The present study included two Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Ciprofloxacin (Cip) functionalized materials (MWCNT-COOH/Fe₃O₄/Cip) were most efficient against all tested bacterial strains; therefore, we conclude that Cu and Ni reduce the effects of Cip. The obtained results indicate that the nanocomposites functionalized with Cip are more effective against selected bacteria strains compared to azithromycin (Azi) functionalized nanocomposites. The current work determined the antibacterial activities of different nanocomposites and gave fresh insights into their manufacture for future research regarding environmental depollution.

The effect of 100-200 nm ZnO and TiO2 nanoparticles on the in vitro-grown soybean plants

Engineered nanomaterials are increasingly used in everyday life applications and, in consequence, significant amounts are being released into the environment. From soil, water, and air they can reach the organelles of edible plants, potentially impacting the food chain and human health. The potential environmental and health impact of these nanoscale materials is of public concern. TiO2 and ZnO are among the most significant nanomaterials in terms of production amounts. Our study aimed at evaluating the effects of large-scale TiO2 (~100 nm) and ZnO (~200 nm) nanoparticles on soybean plants grown in vitro. The effect of different concentrations of nanoparticles (10, 100, 1000 mg/L) was evaluated regarding plant morphology and metabolic changes. ZnO nanoparticles showed higher toxicity compared to TiO2 in the experimental set-up. Overall, elevated levels of chlorophylls and proteins were observed, as well as increased concentrations of ascorbic and dehydroascorbic acids. Also, the decreasing stomatal conductance to water vapor and net CO2 assimilation rate show higher plant stress levels. In addition, ZnO nanoparticle treatments severely affected plant growth, while TEM analysis revealed ultrastructural changes in chloroplasts and rupture of leaf cell walls. By combining ICP-OES and TEM results, we were able to show that the nanoparticles were metabolized, and their internalization in the soybean plant tissues occurred in ionic forms. This behavior most likely is the main driving force of nanoparticle toxicity.

Electrochemical L-Tyrosine Sensor Based on a Glassy Carbon Electrode Modified with Exfoliated Graphene

In this study, a graphene sample (EGr) was synthesized by electrochemical exfoliation of graphite rods in electrolyte solution containing 0.1 M ammonia and 0.1 M ammonium thiocyanate. The morphology of the powder deposited onto a solid substrate was investigated by the scanning electron microscopy (SEM) technique. The SEM micrographs evidenced large and smooth areas corresponding to the basal plane of graphene as well as white lines (edges) where graphene layers fold-up. The high porosity of the material brings a major advantage, such as the increase of the active area of the modified electrode (EGr/GC) in comparison with that of bare glassy carbon (GC). The graphene modified electrode was successfully tested for L-tyrosine detection and the results were compared with those of bare GC. For EGr/GC, the oxidation peak of L-tyrosine had high intensity (1.69 × 10^-5 A) and appeared at lower potential (+0.64 V) comparing with that of bare GC (+0.84 V). In addition, the graphene-modified electrode had a considerably larger sensitivity (0.0124 A/M) and lower detection limit (1.81 × 10^-6 M), proving the advantages of employing graphene in electrochemical sensing.

The Effect of TiO2 Nanoparticles on the Composition and Ultrastructure of Wheat

The present work aims to follow the influence of TiO2 nanoparticles (TiO2 NPs) on bioactive compounds, the elemental content of wheat, and on wheat leaves' ultrastructure. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). The concentration of phenolic compounds, assimilation pigments, antioxidant capacity, elemental content, as well as the ultrastructural changes that may occur in the wheat plants grown in the presence or absence of TiO2 NPs were evaluated. In plants grown in the presence of TiO2 NPs, the amount of assimilating pigments and total polyphenols decreased compared to the control sample, while the antioxidant activity of plants grown in amended soil was higher than those grown in control soil. Following ultrastructural analysis, no significant changes were observed in the leaves of TiO2-treated plants. Application of TiO2 NPs to soil caused a significant reaction of the plant to stress conditions. This was revealed by the increase of antioxidant capacity and the decrease of chlorophyll, total polyphenols, and carotenoids. Besides, the application of TiO2 NPs led to significant positive (K, Zn, Br, and Mo) and negative (Na, Mn, Fe, As, Sr, Sb, and Ba) variation of content.

In Vivo Distribution of Poly(ethylene glycol) Functionalized Iron Oxide Nanoclusters: An Ultrastructural Study

The in vivo distribution of 50 nm clusters of polyethylene glycol-conjugated superparamagnetic iron oxide nanoparticles (SPIONs-PEG) was conducted in this study. SPIONs-PEG were synthesized de novo, and their structure and paramagnetic behaviors were analyzed by specific methods (TEM, DLS, XRD, VSM). Wistar rats were treated with 10 mg Fe/kg body weight SPIONs-PEG and their organs and blood were examined at two intervals for short-term (15, 30, 60, 180 min) and long-term (6, 12, 24 h) exposure evaluation. Most exposed organs were investigated through light and transmission electron microscopy, and blood and urine samples were examined through fluorescence spectrophotometry. SPIONs-PEG clusters entered the bloodstream after intraperitoneal and intravenous administrations and ended up in the urine, with the highest clearance at 12 h. The skin and spleen were within normal histological parameters, while the liver, kidney, brain, and lungs showed signs of transient local anoxia or other transient pathological affections. This study shows that once internalized, the synthesized SPIONs-PEG disperse well through the bloodstream with minor to nil induced tissue damage, are biocompatible, have good clearance, and are suited for biomedical applications.

Wasted Biomaterials from Crustaceans as a Compliant Natural Product Regarding Microbiological, Antibacterial Properties and Heavy Metal Content for Reuse in Blue Bioeconomy: A Preliminary Study

The compliance of crab shells traditionally used as a complex natural product for agricultural soil amendment with modern biofertilizers' quality and safety requirements was investigated. Shells waste from the Blue crab, Callinectes sapidus and the Green crab, Carcinus aestuarii were tested for macronutrients, heavy metals, bacteria content, and antimicrobial properties. Such information is crucial for further utilization of the biogenic powders for any composite formulation in added-value by-products. The calcium carbonate-rich hard tissue yield was 52.13% ± 0.015 (mean ± S.D.) and 64.71% ± 0.144 from the blue and green crabs, respectively. The contents of Pb, Ni, Zn, Cr (VI), and Cu were several orders of magnitude below the prescribed limit by EU biofertilizer legislation, with Fe, Mn (not prescribed), and As being the most abundant. The content of As and Cd from the material considered here was within limits. The shells contain no colony-forming units of Salmonella spp. and compliant levels of Escherichia coli; moreover, the shell micro-powder showed dose-dependent growth inhibition of Pseudomonas aeruginosa and Staphylococcus aureus. In summary, the waste crab shells present a complex natural product as plant biofertilizer following the circular economy concepts.

Single depolymerizing and transport kinesins stabilize microtubule ends

Microtubules are highly dynamic cellular filaments and an accurate control of their length is important for many intracellular processes like cell division. Among other factors, microtubule length is actively modulated by motors from the kinesin superfamily. For example, yeast kinesin-8, Kip3, motors depolymerize microtubules by a cooperative, force- and length-dependent mechanism. However, whether single motors can also depolymerize microtubules is unclear. Here, we measured how single kinesin motors influenced the stability of microtubules in an in vitro assay. Using label-free interference reflection microscopy, we determined the spontaneous microtubule depolymerization rate of stabilized microtubules in the presence of kinesins. Surprisingly, we found that both single Kip3 and nondepolymerizing kinesin-1 transport motors, used as a control, stabilized microtubules further. For Kip3, this behavior is contrary to the collective force-dependent depolymerization activity of multiple motors. Because of the control measurement, the finding may hint at a more general stabilization mechanism. The complex, concentration-dependent interaction with microtubule ends provides new insights into the molecular mechanism of kinesin-8 and its regulatory function of microtubule length.

The Morphological and Anatomical Traits of the Leaf in Representative Vinca Species Observed on Indoor- and Outdoor-Grown Plants

Morphological and anatomical traits of the Vinca leaf were examined using microscopy techniques. Outdoor Vinca minor and V. herbacea plants and greenhouse cultivated V. major and V. major var. variegata plants had interspecific variations. All Vinca species leaves are hypostomatic. However, except for V. minor leaf, few stomata were also present on the upper epidermis. V. minor leaf had the highest stomatal index and V. major had the lowest, while the distribution of trichomes on the upper epidermis was species-specific. Differentiated palisade and spongy parenchyma tissues were present in all Vinca species' leaves. However, V. minor and V. herbacea leaves had a more organized anatomical aspect, compared to V. major and V. major var. variegata leaves. Additionally, as a novelty, the cellular to intercellular space ratio of the Vinca leaf's mesophyll was revealed herein with the help of computational analysis. Lipid droplets of different sizes and aspects were localized in the spongy parenchyma cells. Ultrastructural characteristics of the cuticle and its epicuticular waxes were described for the first time. Moreover, thick layers of cutin seemed to be characteristic of the outdoor plants only. This could be an adaptation to the unpredictable environmental conditions, but nevertheless, it might influence the chemical composition of plants.

Investigating the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the composition and ultrastructure of green leafy vegetables with important nutritional values

The global presence of pharmaceuticals in the environment has been particularly considered a concerning problem with unknown consequences. Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently prescribed drugs in the world, and as a result, they are commonly found in different environmental compartments. In the present work, we studied the effects of NSAIDs (diclofenac, ibuprofen, and naproxen) on the composition and ultrastructure of Atriplex patula L., S. oleracea, and Lactuca sativa L., three green leafy vegetables with significant nutritional value. Contaminant solutions of NSAIDs were applied every two days using concentrations of 0.1 mg L^-1, 0.5 mg L^-1, and 1 mg L^-1. After eight weeks of exposure of the green leafy vegetables to the selected NSAIDs, the chlorophylls (a + b), carotenoids (zeaxanthin, lutein, and ß-carotene), total polyphenol and total flavonoid contents, antioxidant capacity, and the ultrastructural modifications were determined. The obtained results indicated a moderate reduction in the assimilating pigments, total polyphenol and flavonoid contents. In addition, ultrastructural damages of the chloroplasts and cell walls were observed in the leaves of the selected vegetables, which were exposed to abiotic stress-induced by NSAIDs. All data collectively suggest that this group of drugs induced harmful effects on plants, and implicitly they may also negatively affected human health on the long term.

Effects of Long-Term Exposure to Low-Power 915 MHz Unmodulated Radiation on Phaseolus vulgaris L

The morphophysiological response of Phaseolus vulgaris L. to low-power electromagnetic radiation was investigated in order to assess the potential harmful effects of long-term continuous exposure. The plants were grown in two separate electromagnetic field (EMF) shielded rooms, in a controlled, greenhouse-like environment. One batch was continuously irradiated during the growth period (from sowing to maturity) and the other one was used as a reference. An unmodulated signal at 915 MHz (the central frequency between the uplink and downlink of the GSM900 mobile communications band) was used, with a maximum power density of 10 mW/m² measured near the plants. The plants were analyzed using ultraviolet-visible, statistical, morphometric, and electron microscopy methods. Significant differences were observed regarding the height of the plants, number of inflorescences, and chlorophyll and carotenoid content, all closely connected with the ultrastructural changes observed in the leaves. The irradiated batch grew higher (19% increase in plant height, 20% increase in stem and leaves' dry mass), with 18% fewer inflorescences, and extremely long roots (34% increase in dry mass). The ultrastructure of the irradiated leaves showed irregular cells and a higher content of plastoglobules in the chloroplasts. All results indicate that the irradiated plants suffered significant morphological modifications during their long-term exposure to the specific EM radiation. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.