scholarly journals Evaluation of the Effects of Particle Sizes of Silver Nanoparticles on Various Biological Systems

2020 ◽  
Vol 21 (22) ◽  
pp. 8465
Author(s):  
In Chul Kong ◽  
Kyung-Seok Ko ◽  
Dong-Chan Koh
Keyword(s):  
Silver Nanoparticles ◽  
Seed Germination ◽  
Shoot Growth ◽  
Biological Activities ◽  
Algal Growth ◽  
Particle Sizes ◽  
Biosynthetic Activity ◽  
Bacterial Bioluminescence ◽  
Activity Of Enzymes ◽  
Biological Methods

Seven biological methods were adopted (three bacterial activities of bioluminescence, enzyme, enzyme biosynthetic, algal growth, seed germination, and root and shoot growth) to compare the toxic effects of two different sizes of silver nanoparticles (AgNPs). AgNPs showed a different sensitivity in each bioassay. Overall, the order of inhibitory effects was roughly observed as follows; bacterial bioluminescence activity ≈ root growth > biosynthetic activity of enzymes ≈ algal growth > seed germination ≈ enzymatic activity > shoot growth. For all bacterial activities (bioluminescence, enzyme, and enzyme biosynthesis), the small AgNPs showed statistically significantly higher toxicity than the large ones (p < 0.0036), while no significant differences were observed among other biological activities. The overall effects on the biological activities (except shoot growth) of the small AgNPs were shown to have about 4.3 times lower EC50 (high toxicity) value than the large AgNPs. These results also indicated that the bacterial bioluminescence activity appeared to be an appropriate method among the tested ones in terms of both sensitivity and the discernment of particle sizes of AgNPs.

scholarly journals Comparative Effects of Particle Sizes of Cobalt Nanoparticles to Nine Biological Activities

2020 ◽  
Vol 21 (18) ◽  
pp. 6767 ◽  
Author(s):  
In Chul Kong ◽  
Kyung-Seok Ko ◽  
Dong-Chan Koh ◽  
Chul-Min Chon
Keyword(s):  
Seed Germination ◽  
Gene Mutation ◽  
Shoot Growth ◽  
Biological Activities ◽  
Algal Growth ◽  
Physical Factor ◽  
Plant Seed ◽  
Bacterial Gene ◽  
Cobalt Oxide Nanoparticles ◽  
Bacterial Bioluminescence

The differences in the toxicity of cobalt oxide nanoparticles (Co-NPs) of two different sizes were evaluated in the contexts of the activities of bacterial bioluminescence, xyl-lux gene, enzyme function and biosynthesis of β-galactosidase, bacterial gene mutation, algal growth, and plant seed germination and root/shoot growth. Each size of Co-NP exhibited a different level of toxicity (sensitivity) in each biological activity. No revertant mutagenic ratio (greater than 2.0) of Salmonella typhimurium TA 98 was observed under the test conditions in the case of gene-mutation experiments. Overall, the inhibitory effects on all five bacterial bioassays were greater than those on algal growth, seed germination, and root growth. However, in all cases, the small Co-NPs showed statistically greater (total average about two times) toxicity than the large Co-NPs, except in shoot growth, which showed no observable inhibition. These findings demonstrate that particle size may be an important physical factor determining the fate of Co-NPs in the environment. Moreover, combinations of results based on various biological activities and physicochemical properties, rather than only a single activity and property, would better facilitate accurate assessment of NPs’ toxicity in ecosystems.

PRE and POST Herbicidal Activity of Monoterpenes against Barnyard Grass (Echinochloa crus-galli)

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 191-200 ◽  
Author(s):  
Neama A. A. Gouda ◽  
Mona M. G. Saad ◽  
Samir A. M. Abdelgaleil
Keyword(s):  
Phenolic Compounds ◽  
Seed Germination ◽  
Seedling Growth ◽  
Shoot Growth ◽  
Foliar Application ◽  
Biological Activities ◽  
Herbicidal Activity ◽  
Total Phenolic ◽  
Total Phenolic Compounds ◽  
Chlorophyll Contents

Monoterpenes, the major constituents of essential oils, are known for their diverse biological activities. This study was conducted to assess the herbicidal effect of six monoterpenes viz. (R)-carvone, 1,8-cineole, cuminaldehyde, (S)-fenchone, geraniol, (S)-limonene, and (R)-linalool on barnyardgrass under laboratory and glasshouse conditions with a view to explore the possibility of their utilization for future weed management. The effect of monoterpenes on chlorophyll contents and total phenolic compounds was also evaluated. The inhibitory effects of monoterpenes on seed germination and seedling growth were tested at concentrations of 1, 2, 4, 6, and 8 mM. The results showed that geraniol and (R)-carvone caused greatest reduction of seed germination with complete inhibition at the concentrations > 2 mM. Similarly, these two compounds were the most potent inhibiters for root and shoot growth. In general, monoterpenes were less effective against seed germination than seedling growth. Furthermore, the inhibition of root growth by all compounds was greater than that of shoot growth. In foliar application treatments under glasshouse conditions, the monoterpenes reduced the fresh and dry weights, and shoot length of two-leaf stage barnyardgrass at concentrations of 1 and 2%. In addition, the tested monoterpenes caused phytotoxicity symptoms, mainly chlorosis and necrosis, followed by weed death. Complete weed control was observed in the treatments with 1 and 2% of geraniol, and 2% of cuminaldehyde. Further, a reduction of chlorophyll contents and total phenolic compounds of barnyardgrass leaves was noticed, indicating that the monoterpenes cause adverse effect on photosynthesis and weed metabolism. Based on the results of this study, it can be concluded that the monoterpenes, particularly geraniol, (R)-carvone, and cuminaldehyde, can be used as potential natural herbicides.

scholarly journals Biosynthesis of Silver Nanoparticles Mediated by Entomopathogenic Fungi: Antimicrobial Resistance, Nanopesticides, and Toxicity

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 852
Author(s):  
Tárcio S. Santos ◽  
Tarcisio M. Silva ◽  
Juliana C. Cardoso ◽  
Ricardo L. C. de Albuquerque-Júnior ◽  
Aleksandra Zielinska ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Filamentous Fungi ◽  
Entomopathogenic Fungi ◽  
Antimicrobial Agents ◽  
Insect Pests ◽  
Insect Control ◽  
Biological Synthesis ◽  
Biological Methods ◽  
Potential Use

Silver nanoparticles are widely used in the biomedical and agri-food fields due to their versatility. The use of biological methods for the synthesis of silver nanoparticles has increased considerably due to their feasibility and high biocompatibility. In general, microorganisms have been widely explored for the production of silver nanoparticles for several applications. The objective of this work was to evaluate the use of entomopathogenic fungi for the biological synthesis of silver nanoparticles, in comparison to the use of other filamentous fungi, and the possibility of using these nanoparticles as antimicrobial agents and for the control of insect pests. In addition, the in vitro methods commonly used to assess the toxicity of these materials are discussed. Several species of filamentous fungi are known to have the ability to form silver nanoparticles, but few studies have been conducted on the potential of entomopathogenic fungi to produce these materials. The investigation of the toxicity of silver nanoparticles is usually carried out in vitro through cytotoxicity/genotoxicity analyses, using well-established methodologies, such as MTT and comet assays, respectively. The use of silver nanoparticles obtained through entomopathogenic fungi against insects is mainly focused on mosquitoes that transmit diseases to humans, with satisfactory results regarding mortality estimates. Entomopathogenic fungi can be employed in the synthesis of silver nanoparticles for potential use in insect control, but there is a need to expand studies on toxicity so to enable their use also in insect control in agriculture.

scholarly journals Biosynthesis, Characterization, and Biological Activities of Procyanidin Capped Silver Nanoparticles

2020 ◽  
Vol 11 (3) ◽  
pp. 66
Author(s):  
Umar M. Badeggi ◽  
Jelili A. Badmus ◽  
Subelia S. Botha ◽  
Enas Ismail ◽  
Jeanine L. Marnewick ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Food Packaging ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
Bacterial Species ◽  
Bactericidal Effect ◽  
Total Extract ◽  
Selected Area Electron Diffraction ◽  
Ic50 Values ◽  
Inhibitory Activities

In this study, procyanidin dimers and Leucosidea sericea total extract (LSTE) were employed in the synthesis of silver nanoparticles (AgNPs) and characterized by ultraviolet-visible (UV-Visible) spectroscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and dynamic light scattering (DLS) techniques. AgNPs of about 2–7 nm were obtained. DLS and stability evaluations confirmed that the AgNPs/procyanidins conjugates were stable. The formed nanoparticles exhibited good inhibitory activities against the two enzymes studied. The IC50 values against the amylase enzyme were 14.92 ± 1.0, 13.24 ± 0.2, and 19.13 ± 0.8 µg/mL for AgNPs coordinated with LSTE, F1, and F2, respectively. The corresponding values for the glucosidase enzyme were 21.48 ± 0.9, 18.76 ± 1.0, and 8.75 ± 0.7 µg/mL. The antioxidant activities were comparable to those of the intact fractions. The AgNPs also demonstrated bacterial inhibitory activities against six bacterial species. While the minimum inhibitory concentrations (MIC) of F1-AgNPs against Pseudomonas aeruginosa and Staphylococcus aureus were 31.25 and 15.63 µg/mL respectively, those of LSTE-AgNPs and F2-AgNPs against these organisms were both 62.50 µg/mL. The F1-AgNPs demonstrated a better bactericidal effect and may be useful in food packaging. This research also showed the involvement of the procyanidins as reducing and capping agents in the formation of stable AgNPs with potential biological applications.

Sign in / Sign up

Export Citation Format

Share Document