Municipal wastewater viral pollution in Saudi Arabia: effect of hot climate on COVID-19 disease spreading

The viral RNA of SARS-Coronavirus-2 is known to be contaminating municipal wastewater. We aimed to assess if COVID-19 disease is spreading through wastewater. We studied the amount of viral RNA in raw sewage and the efficiency of the sewage treatment to remove the virus. Sewage water was collected before and after the activated sludge process three times during summer 2020 from three different sewage treatment plants. The sewage treatment was efficient in removing SARS-CoV-2 viral RNA. Each sewage treatment plant gathered wastewater from one hospital, of which COVID-19 admissions were used to describe the level of disease occurrence in the area. The presence of SARS-CoV-2 viral RNA-specific target genes (N1, N2, and E) was confirmed using RT-qPCR analysis. However, hospital admission did not correlate significantly with viral RNA. Moreover, viral RNA loads were relatively low, suggesting that sewage might preserve viral RNA in a hot climate only for a short time.

A review on Saudi Arabian wastewater treatment facilities and available disinfection methods: Implications to SARS-CoV-2 control

COVID-19 pandemic has severe impacts on human health and economy worldwide. Aerosols and droplets are the major routes of transmission of SARS-CoV-2 coronavirus causing COVID-19 disease. However, wastewater is a possible transmission pathway. Therefore, many studies have been published about the relation of wastewater and COVID-19 disease. Many studies have shown the presence of viral RNA in wastewater throughout the world recently. Therefore, research on wastewater treatments and disinfection methods are needed. Communities must make sure that the virus is not transmitted via treated wastewater. This review focuses on the Saudi Arabian wastewater treatment and disinfection techniques to assess the possibility of SARS-CoV-2 transmission through wastewaters. In view of the current pandemic situation, the wide analysis of wastewater treatments in Saudi Arabia is needed. The review gives guidelines to develop the wastewater treatment in Saudi Arabia.

Sol-Gel Synthesis of Dy-Substituted Ni0.4Cu0.2Zn0.4(Fe2-xDyx)O4 Nano Spinel Ferrites and Evaluation of Their Antibacterial, Antifungal, Antibiofilm and Anticancer Potentialities for Biomedical Application

Background

The constant rise of microbial biofilm formation and drug resistance to existing antimicrobial drugs poses a significant threat to community health around the world because it reduces the efficacy and efficiency of treatments, increasing morbidity, mortality, and health-care expenditures. As a result, there is an urgent need to develop novel antimicrobial agents that inhibit microbial biofilm formation.

Methods

The [Ni_0.4Cu_0.2Zn_0.4](Fe_2-xDy_x)O₄(x≤0.04) (Ni-Cu-Zn) nano spinel ferrites (NSFs) have been synthesized by the sol–gel auto-combustion process and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and transmission electron microscopy (TEM). The antimicrobial, antibiofilm and antiproliferative activities of Ni-Cu-Zn NSFs were also examined.

Results

The XRD pattern confirms the secondary phase DyFeO₃ and Fe₂O₃ for substituted Dy³⁺ samples, and the crystallite size ranged from 10 to 19 nm. TEM analysis of NSFs revealed that the particles were cube-shaped and 15nm in size. NSFs exhibited significant antimicrobial, antibiofilm and antiproliferative activity. At concentration of 1 mg/mL, it was found that the NSFs (ie, x=0.0, x=0.01, x=0.02, x=0.03 and x=0.04) inhibit biofilm formation by 27.6, 26.2, 58.5, 33.3 and 25% for methicillin-resistant Staphylococcus aureus (MRSA) and 47.5, 43.5, 48.6, 58.3 and 26.6% for Candida albicans, respectively. SEM images demonstrate that treating MRSA and C. albicans biofilms with NSFs significantly reduces cell adhesion, colonization and destruction of biofilm architecture and extracellular polymeric substances matrices. Additionally, SEM and TEM examination revealed that NSFs extensively damaged the cell walls and membranes of MRSA and C. albicans. Huge ultrastructural alteration such as deformation, disintegration and separation of cell wall and membrane from the cells was observed, indicating significant loss of membrane integrity, which eventually led to cell death. Furthermore, it was observed that NSF inhibited the cancer cell growth and proliferation of HCT-116 in a dose-dependent manner.

Conclusion

The current study demonstrated that the synthesized Ni-Cu-Zn NSFs could be used to develop potential antimicrobial surface coatings agents for a varieties of biomedical-related materials and devices in order to prevent the biofilms formation and their colonization. Furthermore, the enhanced antiproliferative properties of manufactured SNFs suggest a wide range of biomedical applications.

Fabrication and in vitro Evaluation of 4-HIA Encapsulated PLGA Nanoparticles on PC12 Cells

Purpose

4-Hydroxyisophthalic acid (4-HIA) is a bioactive compound present in the roots of Decalepis hamiltonii, which has attracted considerable attention in attenuating oxidative stress-related neurodegenerative diseases. However, its efficacy is limited because of its low solubility and bioavailability. Therefore, the present study aimed to encapsulate 4-HIA using biocompatible copolymer polylactide-co-glycolide (PLGA) and evaluate its antioxidant and neuroprotective potential.

Methods

The nanoparticles (NPs) were fabricated by solid/oil/water (s/o/w) emulsion technique and characterized using XRD, SEM, HR-TEM, and FTIR spectroscopy. Antioxidant assays such as 1,1 diphenyl-2-picrylhydrazyl (DPPH), superoxide, and hydroxyl radical scavenging ability were performed to assess the antioxidant potential of the fabricated NPs.

Results

The bioactive component, 4-HIA, was efficiently encapsulated by the PLGA polymer and was found to be spherical and smooth with a size <10nm. 4-HIA showed better scavenging capability in DPPH and superoxide assays as compared to 4-HIA encapsulated PLGA and butylated hydroxytoluene (BHT). In contrast, 4-HIA encapsulated PLGA NPs exhibited a significant hydroxyl radical scavenging activity than 4-HIA and BHT alone. Further, the encapsulated NPs efficiently curtailed hydrogen peroxide (H₂O₂)-induced cytotoxicity in PC12 cells.

Conclusion

Our findings indicate that 4-HIA encapsulated PLGA NPs might be a therapeutic intervention towards the effective management of oxidative stress as it has exhibited efficient neuroprotective potential against H₂O₂-induced oxidative stress in PC12 cells.

Therapeutic development by repurposing drugs targeting SARS-CoV-2 spike protein interactions by simulation studies

The human-to-human transmitted respiratory illness in COVID-19 affected by the pathogenic Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), which appeared in the last of December 2019 in Wuhan, China, and rapidly spread in many countries. Thereon, based on the urgent need for therapeutic molecules, we conducted in silico based docking and simulation molecular interaction studies on repurposing drugs, targeting SARS-CoV-2 spike protein. Further, the best binding energy of doxorubicin interacting with virus spike protein (PDB: 6VYB) was observed to be -6.38 kcal/mol and it was followed by exemestane and gatifloxacin. The molecular simulation dynamics analysis of doxorubicin, Reference Mean Square Deviation (RMSD), Root Mean Square fluctuation (RMSF), Radius of Gyration (Rg), and formation of hydrogen bonds plot interpretation suggested, a significant deviation and fluctuation of Doxorubicin-Spike RBD complex during the whole simulation period. The Rg analysis has stated that the Doxorubicin-Spike RBD complex was stable during 15,000-35,000 ps MDS. The results have suggested that doxorubicin could inhibit the virus spike protein and prevent the access of the SARS-CoV-2 to the host cell. Thus, in-vitro/in-vivo research on these drugs could be advantageous to evaluate significant molecules that control the COVID-19 disease.

Counteraction of Biofilm Formation and Antimicrobial Potential of Terminalia catappa Functionalized Silver Nanoparticles against Candida albicans and Multidrug-Resistant Gram-Negative and Gram-Positive Bacteria

Biofilms not only protect bacteria and Candida species from antibiotics, but they also promote the emergence of drug-resistant strains, making eradication more challenging. As a result, novel antimicrobial agents to counteract biofilm formation are desperately needed. In this study, Terminalia catappa leaf extract (TCE) was used to optimize the TCE-capped silver nanoparticles (TCE-AgNPs) via a one-pot single-step method. Varied concentrations of TCE have yielded different sized AgNPs. The physico-chemical characterization of TCE-AgNPs using UV-Vis, SEM, TEM, FTIR, and Raman spectroscopy have confirmed the formation of nanostructures, their shape and size and plausible role of TCE bio-active compounds, most likely involved in the synthesis as well as stabilization of NPs, respectively. TCE-AgNPs have been tested for antibiofilm and antimicrobial activity against multidrug-resistant Pseudomonas aeruginosa (MDR-PA), methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans using various microbiological protocols. TCE-Ag-NPs-3 significantly inhibits biofilm formation of MDR-PA, MRSA, and C. albicans by 73.7, 69.56, and 63.63%, respectively, at a concentration of 7.8 µg/mL, as determined by crystal violet microtiter assay. Furthermore, SEM micrograph shows that TCE-AgNPs significantly inhibit the colonization and adherence of biofilm forming cells; individual cells with loss of cell wall and membrane integrity were also observed, suggesting that the biofilm architecture and EPS matrix were severely damaged. Moreover, TEM and SEM images showed that TCE-AgNPs brutally damaged the cell wall and membranes of MDR-PA, MRSA, and C. albicans. Additionally, extreme ultrastructural changes such as deformation, disintegration, and separation of cell wall and membrane from the cells, have also been observed, indicating significant loss of membrane and cell wall integrity, which eventually led to cell death. Overall, the research revealed a simple, environmentally friendly, and low-cost method for producing colloidal TCE-AgNPs with promising applications in advanced clinical settings against broad-spectrum biofilm-forming antibiotic-resistant bacteria and candida strains.

Bioprospecting of Rhizosphere-Resident Fungi: Their Role and Importance in Sustainable Agriculture

Rhizosphere-resident fungi that are helpful to plants are generally termed as 'plant growth promoting fungi' (PGPF). These fungi are one of the chief sources of the biotic inducers known to give their host plants numerous advantages, and they play a vital role in sustainable agriculture. Today's biggest challenge is to satisfy the rising demand for crop protection and crop yield without harming the natural ecosystem. Nowadays, PGPF has become an eco-friendly way to improve crop yield by enhancing seed germination, shoot and root growth, chlorophyll production, and fruit yield, etc., either directly or indirectly. The mode of action of these PGPF includes the solubilization and mineralization of the essential micro- and macronutrients needed by plants to regulate the balance for various plant processes. PGPF produce defense-related enzymes, defensive/volatile compounds, and phytohormones that control pathogenic microbes' growth, thereby assisting the plants in facing various biotic and abiotic stresses. Therefore, this review presents a holistic view of PGPF as efficient natural biofertilizers to improve crop plants' growth and resistance.

Padina boryana mediated green synthesis of crystalline palladium nanoparticles as potential nanodrug against multidrug resistant bacteria and cancer cells

Green synthesized nanoparticles (NPs) have emerged as a new and promising alternative to overcome the drug resistance problem. Peculiar nano-specific features of palladium NPs (Pd-NPs) offer invaluable possibilities for clinical treatment. Due to the development of multi-drug resistance (MDR) in pathogenic bacteria and the prevalence of cancers, use of algae-mediated Pd-NPs could be a prospective substitute. Therefore, Pd-NPs were synthesized by a one-step, cost-effective, and environmentally friendly green method using the extract from a brown alga, Padina boryana (PB-extract), and evaluated for their antibacterial, antibiofilm, and anticancer activities. Pd-NPs were physicochemically characterized for size, shape, morphology, surface area, charge, atomic composition, crystal structure, and capping of Pd-NPs by PB-extract biomolecules by various techniques. The data revealed crystalline Pd-NPs with an average diameter of 8.7 nm, crystal size/structure of 11.16 nm/face-centered cubic, lattice d-spacing of 0.226 nm, 28.31% as atomic percentage, surface area of 16.1 m2/g, hydrodynamic size of 48 nm, and zeta-potential of - 28.7 ± 1.6 mV. Fourier-transform infrared spectroscopy (FT-IR) analysis revealed the role of PB-extract in capping of Pd-NPs by various functional groups such as -OH, C=C, C-O, and C-N from phenols, aliphatic hydrocarbons, aromatic rings, and aliphatic amine. Out of 31, 23 compounds were found involved in biosynthesis by Gas chromatography-mass spectrometry (GC-MS) analysis. Isolated strains were identified as MDR Staphylococcus aureus, Escherichia fergusonii, Acinetobacter pittii, Pseudomonas aeruginosa, Aeromonas enteropelogenes, and Proteus mirabilis and Pd-NPs exhibited strong antibacterial/antibiofilm activities against them with minimum inhibitory concentration (MIC) in the range of 62.5-125 μg/mL. Moreover, cell viability assays showed concentration-dependent anti-proliferation of breast cancer MCF-7 cells. Pd-NPs also enhanced mRNA expression of apoptotic marker genes in the order: p53 (5.5-folds) > bax (3.5-folds) > caspase-3 (3-folds) > caspase-9 (2-folds) at 125 μg/mL. This study suggested the possible role of PB-extract capped Pd-NPs for successful clinical management of MDR pathogens and breast cancer cells.

Tumoricidal and Bactericidal Properties of ZnONPs Synthesized Using Cassia auriculata Leaf Extract

In this work, we aimed to synthesize zinc oxide nanoparticles (ZnONPs) using an aqueous extract of Cassia auriculata leaves (CAE) at room temperature without the provision of additional surfactants or capping agents. The formation of as-obtained ZnONPs was analyzed by UV-visible (ultraviolet) absorption and emission spectroscopy, X-ray photoemission spectroscopy (XPS), X-ray diffraction analysis (XRD), energy dispersive X-ray diffraction (EDX), thermogravimetric analysis/differential thermal analysis (TGA-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The XRD results reflect the wurtzite structure of as-prepared ZnONPs, which produced diffraction patterns showing hexagonal phases. The SEM images indicate that the morphology of as-prepared ZnONPs is composed of hexagonal nanostructures with an average diameter of 20 nm. The HR-TEM result shows that the inter-planar distance between two lattice fringes is 0.260 nm, which coincides with the distance between the adjacent (d-spacing) of the (002) lattice plane of ZnO. The fluorescence emission spectrum of ZnONPs dispersed in ethanol shows an emission maximum at 569 nm, revealing the semiconductor nature of ZnO. As-obtained ZnONPs enhanced the tumoricidal property of CAE in MCF-7 breast cancer cells without significant inhibition of normal human breast cells, MCF-12A. Furthermore, we have studied the antibacterial effects of ZnONPs, which showed direct cell surface contact, resulting in the disturbance of bacterial cell integrity.

Effect of Biosynthesized ZnO Nanoparticles on Multi-Drug Resistant Pseudomonas Aeruginosa

Synthesis of nanoparticles using the plants has several advantages over other methods due to the environmentally friendly nature of plants. Besides being environmentally friendly, the synthesis of nanoparticles using plants or parts of the plants is also cost effective. The present study focuses on the biosynthesis of zinc oxide nanoparticles (ZnO NPs) using the seed extract of Butea monsoperma and their effect on to the quorum-mediated virulence factors of multidrug-resistant clinical isolates of Pseudomonas aeruginosa at sub minimum inhibitory concentration (MIC). The synthesized ZnO NPs were characterized by different techniques, such as Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM). The average size of the nanoparticles was 25 nm as analyzed by TEM. ZnO NPs at sub MIC decreased the production of virulence factors such as pyocyanin, protease and hemolysin for P. aeruginosa (p ≤ 0.05). The interaction of NPs with the P. aeruginosa cells on increasing concentration of NPs at sub MIC levels showed greater accumulation of nanoparticles inside the cells as analyzed by TEM.

Biogenic Gold Nanoparticles as Potent Antibacterial and Antibiofilm Nano-Antibiotics against Pseudomonas aeruginosa

Plant-based synthesis of eco-friendly nanoparticles has widespread applications in many fields, including medicine. Biofilm—a shield for pathogenic microorganisms—once formed, is difficult to destroy with antibiotics, making the pathogen resistant. Here, we synthesized gold nanoparticles (AuNPs) using the stem of an Ayurvedic medicinal plant, Tinospora cordifolia, and studied the action of AuNPs against Pseudomonas aeruginosa PAO1 biofilm. The synthesized AuNPs were characterized by techniques such as ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray diffraction, X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy. The AuNPs were spherically shaped with an average size of 16.1 nm. Further, the subminimum inhibitory concentrations (MICs) of AuNPs (50, 100, and 150 µg/mL) greatly affected the biofilm-forming ability of P. aeruginosa, as observed by crystal violet assay and SEM, which showed a decrease in the number of biofilm-forming cells with increasing AuNP concentration. This was further justified by confocal laser scanning microscopy (CLSM), which showed irregularities in the structure of the biofilm at the sub-MIC of AuNPs. Further, the interaction of AuNPs with PAO1 at the highest sub-MIC (150 µg/mL) showed the internalization of the nanoparticles, probably affecting the tendency of PAO1 to colonize on the surface of the nanoparticles. This study suggests that green-synthesized AuNPs can be used as effective nano-antibiotics against biofilm-related infections caused by P. aeruginosa.