Biosynthesis of Zinc Nanoparticles From Actinobacterium Streptomyces Species and Their Biological Potential

BACKGROUND

In today's world, antibiotic-resistant microorganisms are a major concern. There is solid evidence that metal nanoparticles (NPs) tend to have antimicrobial properties. The most effective substitute for antibiotic resistance is the incorporation of metal NPs. The antibacterial properties of NPs are currently being explored and shown to be successful. Zinc (Zn) NPs that are biosynthesized from marine Actinobacterium proved to be more biocompatible, bioactive, and affordable.  Aim: This study aims to investigate the synthesis of ZnNPs from Actinobacterium Streptomyces species and their antimicrobial effects against gram-positive and gram-negative bacteria.

MATERIALS AND METHODS

The current study uses natural, considerably safer processes to synthesize ZnNPs from marine Actinobacteria with little to no negative side effects. It involves sample collection, identification, and isolation of Actinobacterium Streptomyces species. The isolated sample was air-dried, and extracts of ZnNPs were taken. Among the isolates from marine sediment, two Actinobacteria that generate bioactive secondary metabolites-Streptomyces species (MOSEL-ME28) and Rhodococcus rhodochrous (MOSEL-ME29)-were selected for extracellular synthesis of ZnNPs. The antimicrobial activity of the biosynthesized ZnNPs from marine Actinobacteria was analyzed against Staphylococcus (MRSA), Klebsiella pneumoniae, and Streptococcus mutans. The results were statistically analyzed and graphs were created.

RESULTS

ZnNPs obtained from Actinobacterium Streptomyces species exhibited antimicrobial effects against Staphylococcus (MRSA), Klebsiella, and Streptococcus mutans. At 280 nm wavelength, analysis of the UV spectrum showed a notable absorbance value of 1.8. The antibacterial efficacy against Staphylococcus MRSA, Klebsiella species, and Streptococcus mutans was assessed by measuring the zone of inhibition in diameter. The zones of inhibition were 8, 8, and 7 mm on the evaluation for Streptococcus mutans, S. aureus, and Klebsiella species, respectively, at a dose of 75 μg/mL. When the dosage was increased to 100 μg/mL, the inhibition zones were found to be 9.5, 9, and 7.5 mm for the respective bacterial strains.

CONCLUSION

ZnNPs are biosynthesized from marine Actinobacterium Streptomyces species in this research study. They have a significant antimicrobial activity against both gram-positive and negative bacteria. This indicates that ZnNPs have enormous antimicrobial potential and have an extensive spectrum of applications. However, clinical trials must be completed before it can be used safely on patients.

Exopolysaccharides-Mediated ZnO Nanoparticles for the Treatment of Aquatic Diseases in Freshwater Fish Oreochromis mossambicus

Bacterial fish disease outbreaks are a key concern for aquaculture. Complementary feed additives such as immunostimulants can serve as an ideal solution for disease prevention. Herein, we scrutinized the efficacy of exopolysaccharides (EPSs) from probiotic Bacillus licheniformis and EPS-mediated zinc oxide nanoparticles (EPS-ZnO NPs) for a diet to evaluate growth parameters, antioxidant enzyme activities, and immune stimulation together with disease resistance against Aeromonas hydrophila and Vibrio parahaemolyticus in Mozambique tilapia Oreochromis mossambicus. Fish were separated into seven groups, with six experimental groups fed with EPS and EPS-ZnO NPs at 2, 5, and 10 mg/g and a control fed a basal diet. The fish ingesting feed supplemented with EPS and EPS-ZnO NPs at 10 mg/g showed improved growth performance. Cellular and humoral-immunological parameters were tested in serum and mucus after 15 and 30 days of feeding. These parameters were substantially enriched with a 10 mg/g diet (p < 0.05) of EPS and EPS-ZnO NPs in comparison with the control. Furthermore, the EPS and EPS-ZnO NP supplemental diet actively enhanced the antioxidant response (glutathione peroxidase, superoxide dismutase, and catalase). In addition, the supplemental diet of EPS and EPS-ZnO NPs lowered the death rate and improved the disease resistance of O. mossambicus following assessment with A. hydrophila and V. parahaemolyticus at 50 µL. Hence, the overall results suggest that the supplemental diet of EPS and EPS-ZnO NPs might be used to ensure aquaculture feed additives.

Enhanced Antiobesity Efficacy of Tryptophan Using the Nanoformulation of Dendropanax morbifera Extract Mediated with ZnO Nanoparticle

Green synthesis of metal nanoparticles from medicinal plants has provided a broad scope in biomedical research and functional food formulations due to low toxicity. Dendropanax morbifera (DM) is a versatile traditional medicine used for various inflammatory diseases due to its extensive antioxidant activity. We investigated DM as a natural capping agent for Zn²⁺ ions and coloaded it with tryptophan for its penetration and antiobesity behavior. DM zinc oxide nanoparticles (DM-ZnO NPs) were prepared and then entrapped with tryptophan (DM-ZnO-Try nanoemulsion (NE)) for stable formulation using the O/W nanoemulsion method. The hydrodynamic sizes measured by dynamic light scattering for DM-ZnO NPs and DM-ZnO-Try NE are about 146.26 ± 3.31 and 151.16 ± 3.59 nm, respectively. TEM and SEM reveal its morphology. In vitro analysis on both NPs and NE was non-toxic to RAW 264.7 and 3T3-L1 preadipocyte cell line. It significantly reduced the accumulated lipids through lipolysis performed at 10 ug/mL in 3T3-L1 preadipocyte cells. NE suppresses the differentiation of 3T3-L1 adipocytes and lowers triglycerides. Further, the substantial reduction of lipid content is evident with Oil Red O staining and OD measurement. In this present study, the synergetic effect of DM-ZnO NPs and tryptophan is reported, which provides a way for more detailed research on its efficacy for obesity and obesity-associated disorders.

Anticoccidial and antioxidant activities of zinc oxide nanoparticles on Eimeria papillata-induced infection in the jejunum

Nanomedicine has recently emerged as a better option for the treatment of various diseases. Here, we investigated the in vivo anticoccidial properties of zinc oxide nanoparticles (ZNPs). ZNPs were crystalline in nature, with a smooth and spherical surface and a diameter in the range of ~10–15 nm. The X-ray diffraction pattern was utilized to identify the crystalline property of the grown ZNPs, whereas field emission scanning electron microscopy was employed to check the size and morphology of the ZNPs. The data showed that mice infected with Eimeria papillata produced 29.7×10³±1,500 oocysts/g feces on day 5 postinfection. This output was significantly decreased, to 12.5×10³±1,000 oocysts, in mice treated with ZNPs. Infection also induced inflammation and injury of the jejunum. This was evidenced (1) through an increase in the inflammatory histological score, (2) through increased production of nitric oxide and malondialdehyde, and (3) through a decrease in both the glutathione level and goblet cell number in mice jejuna. All these infection-induced parameters were significantly altered during treatment with ZNPs. Our results indicate, therefore, that ZNPs have protective effects against E. papillata-induced coccidiosis.