Nickel oxide nanoparticles: A new generation nanoparticles to combat bacteria Xanthomonas oryzae pv. oryzae and enhance rice plant growth.

Recently, nanotechnology is among the most promising technologies used in all areas of research. The production of metal nanoparticles using plant parts has received significant attention for its environmental friendliness and effectiveness. Therefore, we investigated the possible applications of biological synthesized nickel oxide nanoparticles (NiONPs). In this study, NiONPs were synthesized through biological method using an aqueous extract of saffron stigmas (Crocus sativus L). The structure, morphology, purity, and physicochemical properties of the obtained NPs were confirmed through Scanning/Transmission Electron Microscopy attached with Energy Dispersive Spectrum, X-ray Diffraction, and Fourier transform infrared. The spherically shaped NiONPs were found by Debye Scherer's formula to have a mean dimension of 41.19 nm. The application of NiONPs in vitro at 50, 100, and 200 µg/mL, respectively, produced a clear region of 2.0, 2.2, and 2.5 cm. Treatment of Xoo cell with NiONPs reduced the growth and biofilm formation, respectively, by 88.68% and 83.69% at 200 µg/mL. Adding 200 µg/mL NiONPs into Xoo cells produced a significant amount of ROS in comparison with the control. Bacterial apoptosis increased dramatically from 1.05% (control) to 99.80% (200 µg/mL NiONPs). When compared to the control, rice plants treated with 200 µg/mL NiONPs significantly improved growth characteristics and biomass. Interestingly, the proportion of diseased leaf area in infected plants with Xoo treated with NiONPs reduced to 22% from 74% in diseased plants. Taken together, NiONPs demonstrates its effectiveness as a promising tool as a nano-bactericide in managing bacterial infection caused by Xoo.

Bio-functionalized nickel-silica nanoparticles suppress bacterial leaf blight disease in rice (Oryza sativa L.).

Introduction: Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most devastative diseases that threatens rice plants worldwide. Biosynthesized nanoparticle (NP) composite compounds have attracted attention as environmentally safe materials that possess antibacterial activity that could be used in managing plant diseases. Methods: During this study, a nanocomposite of two important elements, nickel and silicon, was biosynthesized using extraction of saffron stigmas (Crocus sativus L.). Characterization of obtained nickel-silicon dioxide (Ni-SiO2) nanocomposite was investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission/Scanning electron microscopy (TEM/SEM), and energy-dispersive spectrum (EDS). Antibacterial activities of the biosynthesized Ni-SiO2 nanocomposite against Xoo were tested by measuring bacterial growth, biofilm formation, and dead Xoo cells. Results and discussions: The bacterial growth (OD600) and biofilm formation (OD570) of Xoo treated with distilled water (control) was found to be 1.21 and 1.11, respectively. Treatment with Ni-SiO2 NPs composite, respectively, reduced the growth and biofilm formation by 89.07% and 80.40% at 200 µg/ml. The impact of obtained Ni-SiO2 nanocomposite at a concentration of 200 µg/ml was assayed on infected rice plants. Treatment of rice seedlings with Ni-SiO2 NPs composite only had a plant height of 64.8 cm while seedlings treated with distilled water reached a height of 45.20 cm. Notably, Xoo-infected seedlings treated with Ni-SiO2 NPs composite had a plant height of 57.10 cm. Furthermore, Ni-SiO2 NPs composite sprayed on inoculated seedlings had a decrease in disease leaf area from 43.83% in non-treated infected seedlings to 13.06% in treated seedlings. The FTIR spectra of biosynthesized Ni-SiO2 nanocomposite using saffron stigma extract showed different bands at 3,406, 1,643, 1,103, 600, and 470 cm-1. No impurities were found in the synthesized composite. Spherically shaped NPs were observed by using TEM and SEM. EDS revealed that Ni-SiO2 nanoparticles (NPs) have 13.26% Ni, 29.62% Si, and 57.11% O. Xoo treated with 200 µg/ml of Ni-SiO2 NPs composite drastically increased the apoptosis of bacterial cells to 99.61% in comparison with 2.23% recorded for the control. Conclusions: The application of Ni-SiO2 NPs significantly improved the vitality of rice plants and reduced the severity of BLB.

Zinc Oxide Nanoparticles Promise Anticancer and Antibacterial Activity in Ovarian Cancer.

BACKGROUND: Ovarian cancer is the most lethal cancer in gynaecology. Surgery, chemotherapy, and radiotherapy are the most often used cancer-fighting strategies. Post-surgery infection is fairly prevalent, especially among people with insufficient immunity. Zinc oxide nanoparticles (ZnOnps) have amazing biomedical features as anticancer and antibacterial agents. METHODS: We investigated the behaviour of ZnOnps synthesized by green methods on ovarian cancers using established human ovarian cancer cell lines, besides the antibacterial action toward models of gram + ve and gram -ve bacteria. The cytotoxic effect of ZnOnps was calculated using a Sulforhodamine B (SRB) trial. Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were tested as models for gram + ve and gram -ve bacteria. The selected bacteria were subjected to concentrations of 20, 40, 80, and 100 µg/ml. RESULTS: The synthesized ZnOnps induced 50% inhibitory concentration (IC50) at a concentration of 27.45 µg/ml. The diameter of inhibition ranged between 20.16 ± 0.16 and 27 ± 0.57 mm for S. aureus and 25.66 ± 0.33 to 31 ± 0.33 mm for E. coli. ZnOnps antagonistic effect statistically differed with neomycin, cefaclor, and cefadroxil. CONCLUSIONS: Green synthesis of ZnOnps is easily prepared, low cost, non-toxic, and eco-friendly. Their cytotoxic action on SKOV3 cells and their antibacterial characteristics pave the way to be an alternative therapy for ovarian cancer and S. aureus and E. coli infection.

Is Noise From Suctioning Harmful to Surgeons' Hearing?

PURPOSE: A growing concern in the community of oral and maxillofacial surgeons (OMSs) is the progressive hearing loss that has become more evident in older surgeons. Very few studies have focused on the effects on a surgeon's hearing based on his or her environment. The purpose of this study was to investigate whether the noise produced by suction, compared with federal guidelines, could have a damaging effect on the hearing of OMSs. MATERIALS AND METHODS: A CEM DT-8851 industrial high-accuracy digital sound noise level meter data logger (CEM Instruments, Bengal, India) was used to capture the sound intensities in various procedures. The sound meter was used to record the intensities of sound produced, in decibels, in clinics and operating rooms. The analysis was divided into different variables: non-drilling/suction (in which neither a drill nor suction was used but suction was on), suction, drilling, suction and drilling, suction and irrigation, and Yankauer suction. RESULTS: A total of 50 clinic and 50 operating room procedures were recorded, focusing on suction. The noise intensities captured were analyzed based on federal workplace standards. Compared with non-drilling/suction, all other noise exposures on average were greater in intensity and statistically significant with P < .0001. Both the maximum and minimum intensity recorded occurred during non-drilling/suction periods. Noise intensities exceeded 85 dB only 0.04% of the time. CONCLUSIONS: The hypothesis that suction noise intensity would exceed federal guidelines was not supported and therefore was not accepted. However, it cannot conclusively be said that surgeons are not experiencing hearing loss due to their work-related noise exposure. The extent to which OMSs are exposed to this type of setting could be the cause of their progressive hearing loss because federal guidelines are based on 8-hour workdays and 16 hours of being in a quiet environment. A longitudinal study observing specific surgeons through a substantial period would perhaps be able to give more definitive results.

How Much Noise Is an Oral and Maxillofacial Surgeon Exposed to?

PURPOSE: A common concern among oral and maxillofacial surgeons (OMSs) is progressive hearing loss throughout their careers. Although this has not been critically studied, there could be several factors that contribute to this detriment, including drills, saws, suction, music, and other sounds within the closed operating environment. This study observed the intensity of noise in operating rooms (ORs) and clinical settings during the use of drills, saws, surgical handpieces, and other tools. MATERIALS AND METHODS: In this cross-sectional study, sound intensities were measured in decibels using a CEM DT-8851 industrial high-accuracy digital sound noise level meter data logger in clinics and ORs. The device measured sound intensities during the entire duration of the procedures. The recorded drilling periods were extracted from the data and t tests were run to determine whether a statistically relevant difference existed between the non-drilling and drilling periods. In addition, the duration during which intensity was greater than or equal to 85 dB was measured. RESULTS: Fifty procedures were recorded in the clinical setting and 50 were recorded in the OR. The results of this study proved that OMSs were indeed exposed to sound intensities in decibels that exceeded Occupational Safety and Health Administration (OSHA) guidelines, but these exposures occurred less than 1% of the time. The maximum recorded intensities in the clinic and OR were during a non-drilling period and these were attributed to suction. CONCLUSION: OSHA guidelines were exceeded in clinical and OR settings, but the results were not relevant. The authors believe this is a very promising study for future endeavors. They found that the threshold set by OSHA was exceeded at points during surgical procedures in the clinic and OR. This will prompt future studies focusing on recordings when suction is used and longitudinal studies of individual OMSs.