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Background: Elemental sulfur (S0) is a cost-efficient fertilizer and the least rapidly utilizable source of S for soil microorganisms and plants. Its bacterial-mediated oxidation to sulfates is dependent on particle size. Finely formulated (micronized, nanosized) S0 exerts enhanced oxidation rate and benefit due to nutrient availability and crop nutrition efficiency. Graphene oxide (GO) affects soil properties both negatively and positively. A pot experiment was carried out with lettuce using soil supplemented with S0 in different composition, applied alone or in combination with GO. The following variants were tested: control, GO, micro-S0, micro-S0 + GO, nano-S0, nano-S0 + GO. Results: Nanosized S0 improved most of enzyme activities (dehydrogenase, arylsulfatase, N-acetyl-β-d-glucosaminidase, β-glucosidase, phosphatase). However, respirations induced by d-glucose, protocatechuic acid, l-arginine were decreased. GO mitigated negative to neutral effect of micro-S0 in the soil pH, dehydrogenase and urease activity. Furthermore, micro-S0 positively affected basal respiration and respirations induced by d-trehalose and N-acetyl-β-d-glucosamine. Nano-S0 + GO improved plant biomass yield and enzyme activities. However, nano-S0 + GO significantly decreased all substate-induced respirations. Conclusions: The benefit of soil treatment with nano-/micro-sized S0 and its combination with GO on soil biological parameters was partially demonstrated. [ABSTRACT FROM AUTHOR]

Background: Development of new nanomaterials that inhibit or kill bacteria is an important and timely research topic. For example, financial losses due to infectious diseases, such as diarrhea, are a major concern in livestock productions around the world. Antimicrobial nanoparticles (NPs) represent a promising alternative to antibiotics and may lower antibiotic use and consequently spread of antibiotic resistance traits among bacteria, including pathogens. Results: Four formulations of zinc nanoparticles (ZnA, ZnB, ZnC, and ZnD) based on phosphates with spherical (ZnA, ZnB) or irregular (ZnC, ZnD) morphology were prepared. The highest in vitro inhibitory effect of our NPs was observed against Staphylococcus aureus (inhibitory concentration values, IC50, ranged from 0.5 to 1.6 mmol/L), followed by Escherichia coli (IC50 0.8–1.5 mmol/L). In contrast, methicillin resistant S. aureus (IC50 1.2–4.7 mmol/L) was least affected and this was similar to inhibitory patterns of commercial ZnO-based NPs and ZnO. After the successful in vitro testing, the in vivo study with rats based on dietary supplementation with zinc NPs was conducted. Four groups of rats were treated by 2,000 mg Zn/kg diet of ZnA, ZnB, ZnC, and ZnD, for comparison two groups were supplemented by 2,000 mg Zn/kg diet of ZnO-N and ZnO, and one group (control) was fed only by basal diet. The significantly higher (P < 0.05) Zn level in liver and kidney of all treated groups was found, nevertheless Zn NPs did not greatly influence antioxidant status of rats. However, the total aerobic and coliform bacterial population in rat feces significantly decreased (P < 0.05) in all zinc groups after 30 d of the treatment. Furthermore, when compared to the ZnO group, ZnA and ZnC nanoparticles reduced coliforms significantly more (P < 0.05). Conclusions: Our results demonstrate that phosphate-based zinc nanoparticles have the potential to act as antibiotic agents. [ABSTRACT FROM AUTHOR]

Graphical abstract showing the nanozyme-enzyme cascade complex system. [Display omitted] • Biomimetic rGO-CeO 2 NC possesses enzyme-mimetic property towards H 2 O 2. • rGO-CeO 2 NC forms a cascade system as NZ-natural enzyme with model enzyme GO x. • CeO 2 NPs was accredited with peroxidase-mimicking and electron acceptor properties. Nanomaterials with enzyme-like activity (nanozymes) are known to be suitable alternatives for natural enzymes tolerating unfavorable pH and temperature conditions. The enzyme-like activity of CeO 2 nanoparticles was already reported and used in electrochemical sensing, where the peroxidase or oxidase-like activities of CeO 2 NPs are mainly used. This work aims to justify the role/s that CeO 2 may play in electrochemical sensing as a nanozyme and acts as a mediator. To this end, a reduced graphene oxide-CeO 2 was prepared and used in two electrochemical sensing configurations. In first configuration, H 2 O 2 reduction was catalyzed at the glassy carbon electrode modified with the rGO-CeO 2 nanocomposite (rGO-CeO 2 NC). The reduction current obtained upon the presence of H 2 O 2 was attributed to a mediator role having a linear range of 100.0–800.0 µmol L−1 with a limit of detection (LOD) and limit of quantification (LOQ) of 15.9 µmol L−1 and 52.9 µmol L−1, respectively. In another configuration, glucose oxidase was used as a model enzyme with the rGO-CeO 2 NC. The oxidation signal obtained upon adding glucose was attributed to the electron-accepting role of the CeO 2 NPs. The analytical figures of merit obtained for both configurations indicated their high sensitivity, selectivity, and reproducibility. The linear detection range for the nanozyme-enzyme cascade system was 100.0–800.0 µmol L−1 with a LOD and LOQ of 18.7 µmol L−1 and 62.3 µmol L−1, respectively. Moreover, the flow injection analysis was enabled due to the short response time in analysis with the prepared sensor. The possibility for applying the developed nanozyme in nanozyme-enzyme cascade system in clinical and food analysis for determination of glucose was verified by studying the interference of various compounds similar to glucose in structure and typical drugs taken by diabetic patients. [ABSTRACT FROM AUTHOR]

Binary-blend films of furcellaran and gelatin (FUR/GEL) and FUR/GEL composite films reinforced with selenium nanoparticles (SeNPs) or silver nanoparticles (AgNPs) were prepared using a solution casting method. The effects of SeNPs and AgNPs on the physical, mechanical, structural, antibacterial properties of the furcellaran/gelatin-based films were examined. It follows from these examinations that the incorporation of SeNPs and AgNPs leads to an increase in thickness, water content, modulus of elasticity, elongation at break, and antimicrobial activity when higher parameters a*, b*, and ΔE are observed in nanocomposite films with AgNPs compared to those enriched with SeNPs. Compared with control film, the addition of nanoparticles significantly decreased solubility and swelling degree. Films containing SeNPs show greater antimicrobial activity against Escherichia coli , Staphylococcus aureus and multi resistant Staphylococcus aureus than films containing AgNPs. [ABSTRACT FROM AUTHOR]