Effect of Titanium, Silver and Zinc Nanoparticles on Microalgae in the Aquatic Environment

Metallic nanoparticles (MNPs) are commonly incorporated in products found in households, industries, and agriculture. The presence of MNPs in the aquatic environment causes damage to living organisms and pollutes the water body rendering it harmful for human consumption. Several studies have been made on the toxicity of MNPs toward microalgae. Most of these studies reported changes in the cellular structure, growth rate, pigments, proteins, and enzymatic activity of microalgae. This review paper focuses on the toxic effects of titanium, zinc, and silver nanoparticles on microalgae in the aquatic environment. A better understanding of the behavior of MNPs in the ecosystem will allow scientists to produce environmentally safe MNPs

Antibacterial Efficacy of Zinc oxide nanoparticles against Serratia marcescens (ATCC 43862) and Enterococcus faecalis (ATCC 29121)

Zinc oxide nanoparticles (ZnO NPs) are a novel and alternative biomaterial for active biomedical applications among all metal and metallic oxide nanoparticles due to less toxicity and biocompatibility with human cells. In this study, we studied the growth curve of Serratia marcescens and Enterococcus faecalis to identify the mid-log phase of the bacterial growth to perform the exposure with ZnO NPs for investigating the antibacterial efficacy. The INT assay was used to determine the anti-bactericidal efficiency of ZnO NPs against S. marcescens and E. faecalis. The results showed that both the test bacteria attained the mid-log phase at the 5th hour. The determination of minimum inhibitory concentration (MIC) demonstrated a higher efficacy of ZnO NPs on the Gram-positive bacterium E. faecalis compared to the Gram-negative bacterium S. marcescens. The present study reports a higher susceptibility of Gram-positive bacterium over Gram-negative bacterium to the treatment of ZnO NPs

Structure and Reactivity of Halogenated GC PNA Base Pairs – A DFT Approach

The present study explored the structural and reactivity relationship of halogenated G-C PNA base pairs using density functional theory (DFT) calculations. The halogens such as F, Cl, and Br are substituted by replacing H atoms involved in H-bonds of the base pairs. All structures were optimized using the B3LYP/6-311++G** theory level, and positive frequencies confirmed their equilibrium states. To understand the structural variations of the considered halogenated systems, the bond distances of R─X, R─H, and X/H•••Y and the bond angles of R─X•••Y were analyzed. The obtained structural parameters and interaction energies are comparable with the previous theoretical reports. In addition, the interaction energies (Eint) and quantum molecular descriptors (QMD) are also calculated to understand the difference between halogenated PNA systems and their non-halogenated counterparts. In this study, the enhancement in the reactivity properties  of halogenated PNA systems has been demonstrated, which indicates their improved responsive characteristics in various chemical reactions. Based on the available results, the halogenated PNA systems, carefully considering their substitutional position, facilitate better accommodation for the triplex formation of dsDNA/dsRNA. Therefore, it is concluded that the improved reactivity properties of halogenated PNA base pairs would make them potential candidates for various biological applications

Phytochemical analysis and antimicrobial potential of Bauhinia tomentosa leaf extracts

Herbal medications have high demand in both advanced and budding nations because of their increased bioavailability and minimal side effects. In the present study, the ethanolic and acetone extracts from Bauhinia tomentosa leaf were investigated for their antibacterial potential against Gram-positive (Staphylococcus aureus), Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa) and yeast (Candida albicans). Phytochemical examination revealed the presence of diverse secondary metabolites, such as flavonoids, alkaloids, phenolic compounds, tannins, and saponins in leaf extracts. GC-MS analysis detected 15 chemical constituents in the extracts, with the major compounds such as 2-Phenyl-1-3- Oxazol, Caryophyllne, dodecanoic acid, d-glycero-d-galacto-haptose, Phytol, Tetradecanoic acid, 1-Hexacosanol, Isophytol, Oleic acid, 7H-Purine-2-amine,7-methyl, and eicosane. Antibiotics study have been used to explore drug resistance in pathogens. These extracts exhibited concentration-dependent antibacterial activity against the tested bacterial strains. The acetone displayed higher antibacterial activity than the ethanol extract, which could be attributed to the efficiency of the solvent extract in extracting the bioactive compounds. The findings of this study offer valuable information regarding the phytochemical composition and antibacterial potential of B. tomentosa leaf extract. The bioactive compounds identified through GC-MS analysis may be responsible for the observed antibacterial activity. Furthermore, the leaf extracts were non-toxic, and their potent antibacterial effects may be attributed to the presence of bioactive phytoconstituents. Future studies may contribute to the development of B. tomentosa based antimicrobial agents with potential therapeutic applications

The Effect of Titanium Dioxide Nanoparticles on Haematococcus pluvialis Biomass Concentration

The increased release of Titanium dioxide nanoparticles (TiO2 NPs) into the aquatic ecosystem is caused by the augmented utilization of nanoparticles in personal care and household products. This has resulted in the contamination of marine, aquatic, and ground water resources, causing adverse impacts on the biota and flora, both in vivo and in vitro. The main purpose of this research was to examine the negative impacts of TiO2 NPs on the bioaccumulation of Haematococcus pluvialis. The interaction and buildup of  TiO2 NPs on H. pluvialis were studied using scanning electron microscopy (SEM). The exposure of H. pluvialis to TiO2 NPs with increasing concentrations (5–100 μg/mL) and time intervals (24 h to 96 h) impacted the biomass concentration of the microalgae. The SEM images provided evidence of changes in characteristics and impairment of the exterior of exposed cells. The findings revealed that the exposure of H. pluvialis to TiO2 NPs resulted in a decline in biomass, which was dependent on the concentration and duration of exposure. The most severe adverse effects were observed after 96 hours of exposure, with a reduction of 43.29 ± 2.02% of biomass concentration. This study has demonstrated that TiO2 NPs harm H. pluvialis, as evidenced by the negative impact on algal biomass resulting from the binding and buildup of these particles on microalga H. pluvialis. To sum up, the decline in algal growth is caused by the accumulation and interaction of TiO2 NPs on microalgae scoring the adverse effects on the growth of H. pluvialis by TiO2 NPs. The findings of this study call for novel screening methods to detect and eliminate TiO2 NPs contamination in aquatic sources used for the cultivation of microalgae which may otherwise pose delirious effects to the consumers

Cytotoxic Study of Zinc Oxide Nanoparticles on Cervical Cancer Cell Line

The advancement of nanomedicine drugs as an outcome of nanotechnology offers tremendous potential to enhance cancer-fighting tactics. Scientists have begun studying the role of NPs in immunotherapy, an area that is particularly beneficial in treating malignancies. Conventional treatment of cancer uses medications known as chemotherapy that frequently cause adverse effects on healthy tissues. Zinc is a vital micronutrient for the well-being of humans; therefore, nanomaterials such as zinc oxide nanoparticles (ZnO NPs) are progressively appealing as cutting-edge medical agents with implementations like anticancer properties. A bottom-up approach was utilized to chemically produce the ZnO NPs, which were characterized using Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray analysis (EDX). MTT assays have been carried out to study the cell viability percentage against multiple ZnO NPs concentrations and durations. The white ZnO NPs displayed a diverse morphology within the nanoscale range, featuring rod and spherical shapes. This synthesis was confirmed through EDX, which revealed distinct peaks corresponding to zinc and oxygen, affirming the formation of pure ZnO NPs. MTT assay data showed that ZnO NPs had a dose and time-dependent cytotoxicity against HeLa cells. This observation suggests that the ZnO NPs possess the potential to combat cancer and may hold promise for applications in biomedical research, particularly in the development of anticancer drugs

Short-term cytotoxicity of zinc oxide nanoparticles on Chlorella vulgaris

Zinc oxide nanoparticles (ZnO NPs) are widely used in industrial and personal care products. The use of these nanoparticles (NPs) has created residues that contaminate the environment, thus cytotoxicity studies of the NPs in biological system is required. Most of the recent cytotoxicity studies has however focused on long-term exposure of the NPs to the biological system. In this study, the cytotoxicity effects of short-term exposure of ZnO NPs to Chlorella vulgaris are reported. The algal cells were exposed to 10, 50, 100, 150, and 200 mg/L of ZnO NPs for 12 h. The toxicity effects of ZnO NPs were then determined through the changes in fluorescence emission of chlorophyll, algal biomass and the viable cell count. The results showed a decrease in the chlorophyll content, algal biomass and cell viability after treatment with ZnO NPs as compared with control. Through this study, the effects of ZnO NPs to C. vulgaris were confirmed. The significant responses of the algal cells to ZnO NPs in a short duration of exposure reflect the potential of the algal cells to be used as bioindicators of ZnO NPs in the aquatic environment

ANTIVIRAL PROPERTIES OF MICROALGAE AND CYANOBACTERIA

The recent outbreak of Corona Virus Disease (COVID-19) and the surge in accelerating the development of a vaccine to fight against the SARS-CoV-2 virus has imposed greater challenges to humanity worldwide. There is lack of research into the production of effective vaccines and methods of treatment against viral infections. As of now, strategies encompassing antiviral drugs and corticosteroids alongside mechanical respiratory treatment are in practice as frontline treatments. Though studies have reported that microalgae possess antiviral properties, only a few cases have presented the existence of antiviral compounds such as algal polysaccharides, lectins, aggluttinins, scytovirin, algal lipids such as sulfoquinovosyldiacylglycerol (SQDG), monogalactosyldiacylglycerides (MGDG) and digalactosyldiacylglycerides (DGDG), and algal biopigments especially chlorophyll analogues, marennine, phycobiliproteins, phycocyanin, phycoerythrin and allophycocyanin that are derived from marine and freshwater microalgae. Given the chemodiversity of bioactive compounds from microalgae and the present scenario, algal biotechnology is seen as a prospective source of antiviral and anti-inflammatory compounds that can be used to develop antiviral agents. Microalgae with potential as antivirals and microalgae derived functional compounds to treat viral diseases are summarized and can be used as a reference in developing algae-derived antivirals to treat SARS-CoV-2 and other similar viruses

THERAPEUTIC APPLICATIONS OF Spirulina AGAINST HUMAN PATHOGENIC VIRUSES

Viruses can spread worldwide and the early detection of emerging infectious diseases and outbreaks in humans and animals is important for effective surveillance and prevention. Viruses such as human immunodeficiency virus (HIV), swine flu, and influenza virus are some of the viruses that spread diseases worldwide. However, the non-availability of effective antiviral drugs and the drug-resistance among the virus and host have become the major problems in controlling viral infections. The natural products from microalgae can be an alternative therapeutic agent to control viral infections in humans. Spirulina is a well-known cyanobacterium that has been consumed by humans as a food supplement for more than centuries without side-effects. Spirulina possesses high nutritional values and provides numerous health benefits to the consumers. Spirulina can be an alternative natural therapeutic agent for numerous virus infections as it contains several bioactive compounds with proven antiviral effect on enveloped viruses (Herpes simplex virus, measles virus, mumps virus) and non-enveloped viruses (astrovirus, rotavirus) by preventing the spread of the virus in the host cells. Spirulina also serves as a natural supplement that strengthens the immune system. This review focuses on the antiviral properties and immunostimulant effects of Spirulina as a potential therapeutic supplement on human health

Impact of Metallic Nanoparticles on the Nutritional Values of Spirulina

Spirulina has high nutritional values and anti-oxidative properties. It is a staple diet due to its easy cultivation and greater nutritional values in biological macromolecules (proteins, lipids, and carbohydrates), pigments (chlorophyll, carotenoids, phycobiliproteins) vitamins, minerals, phenolic compounds, and amino acids. Spirulina also has been used as a nutraceutical to treat numerous diseases and disorders due to its promising therapeutic values. However, extensive anthropogenic activities cause the discharge of metals and metallic nanoparticles into the environment that might cause toxicity to marine and freshwater microalgae due to bioaccumulation. The presence of metals in the environment beyond the normal range does not only affect the growth but also the nutritional values of microalgae. The nutritional properties and usage of Spirulina along with the harmful effects of metals and metallic nanoparticles on Spirulina are highlighted and summarized in this paper