Phytotoxic effects of seaweed mediated copper nanoparticles against the harmful alga: Lyngbya majuscula.

In this study, copper nanoparticles (Cu-NPs) were synthesized using Corallina officinalis Linnaeus and Corallina mediterranea Areschoug aqueous extracts. Transmission Electron microscope indicated that the biosynthesized Cu-NPs averaged 12.7 nm and 13.6 nm for C. Officinalis and C. mediterranea, respectively. As reported by the FT-IR analyses, the algal extracts contain phyto-chemicals such as proteins, carboxylic acids, complex carbohydrates; these compounds will act as encapsulating agents and be reduced from copper sulphate to Cu-NPs. Energy-dispersive analyses X-ray (EDX) confirmed the copper composition in the synthesized Cu-NPs. The biosynthesized Cu-NPs arrested the growth of Lyngbya majuscula and presented in time and concentration dependent trends. At a concentration of 2 µg/mL, Cu-NPs, synthesized by C. officinalis exerted 85 ± 4% reduction of the algae dry weight. Increasing Cu-NPs concentration led to excellent reduction, which is a very promising result. Cupper-NPs synthesized by C. mediterranea produced moderate effects on L. majuscula. The results also indicated that there were sharp decreases in chlorophyll a content in L. majuscula with the increase in Cu-NPs concentrations. Using 4 µg/mL of Cu-NPs derived from C. officinalis, chlorophyll a decreased by 48 ± 5%. On the other hand, lower reductions in chlorophyll a were recorded upon using Cu-NPs synthesized using C. mediterranea (36 ± 3% and 41 ± 5% reductions at concentrations of 2 µg/mL and 4 µg/mL, respectively). The results of this study suggested that the bioactive and allelopathic compounds derived from the two algal extracts coating the (Cu2+) together with (Cu2+) are responsible for the inhibitive impacts of Cu-NPs on L. majuscula.

Phytoplankton abundance and structure as indicator of water quality in the drainage system of the Burullus Lagoon, southern Mediterranean coast, Egypt.

This study represents the first detailed account of phytoplankton community structure and seasonal succession in eight drain sites and the Brimbal Canal influx into the Burullus Lagoon. The phytoplankton characteristics were studied based on the data collected seasonally over 4 years, from summer 2012 to spring 2016. Various indices such as Palmer's and Shannon's biotic indices were used for the assessment of the water quality of the different drains. There were a total of 194 species belonging to 65 genera and 6 groups: Bacillariophyceae (76 species), Chlorophyceae (59 species), Cyanophyceae (30 species), Euglenophyceae (25 species), Dinophyceae (3 species), and Xanthophyceae (1 species). The phytoplankton community was dominated with diatoms, green algae, and euglenoids such as Cyclotella, Scenedesmus, Navicula, Nitzschia, Ankistrodesmus, Chlorella, and Euglena. Maximum and minimum phytoplankton abundance was recorded at the Brimbal Canal and Hooks Drain. Maximum and minimum species diversities (H') were found at the Hooks Drain (2.564) and Burullus Drain (2.055). Species evenness fluctuated between 0.595 (Burullus Drain) and 0.750 (West Burullus Drain). The total score of algal genus pollution index and the algal species pollution index at the different drains showed that Drain 7 and the West Burullus Drain had moderate pollution, and the total score of the other drains were greater than 20 indicating the confirmed high organic pollution. Thus, the present investigation can be considered an attempt to use the phytoplankton community as a bioindicator of organic pollution.

Application of biosynthesized silver nanoparticles against a cancer promoter cyanobacterium, Microcystis aeruginosa.

BACKGROUND: Nanotechnology opens new applications in many fields including medicine. Among all metallic nanoparticles, silver nanoparticles (silver NPS) have proved to be the most effective against a large variety of organisms including toxic cyanobacteria. MATERIALS AND METHODS: Silver NPs were biosynthesized in vivo with different alga species namely, Spirulina platensis, Chlorella vulgaris and Scenedesmus obliquus following two scenarios. First: by suspending a thoroughly washed algae biomass in 1 mM aqueous AgNO3 solution. Second: by culturing them individually in culture media containing the same concentration of AgNO3. Silver NPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis (EDX) and Fourier transform infra-red (FTIR) spectroscopy. The biosynthesized silver NPs were tested for cytotoxic activity against a cancer promoter cyanobacteruim Microcystis aeruginosa, considering effects on cell viability and chlorophyll content. RESULTS: The surface plasmon band indicated the biosynthesis of silver NPs at ~400 nm. Transmission electron microscopy (TEM) revealed that the silver NPs had a mean average size below 100 nm. Energy-dispersive analysis X-ray (EDX) spectra confirmed the presence of silver element. FTIR spectral analyses suggested that proteins and or polysaccharides may be responsible for the biosynthesis of silver NPs and (-COO-) of carboxylate ions is responsible for stabilizing them. The toxic potentialities of the biosynthesized silver NPs against the cancer promoter cyanobacterium, Microcystis aeruginosa showed high reduction in viable cells count and the total chlorophyll content. CONCLUSIONS: The potential activity of the biosynthesized silver NPs from the studied algae species against Microcystis aeruginosa cells is expected to be mainly mediated by the release of silver ions (Ag+) from the particle surface and bioactive compounds as indicated by FTIR analysis.

Cytotoxic activity of biosynthesized gold nanoparticles with an extract of the red seaweed Corallina officinalis on the MCF-7 human breast cancer cell line.

BACKGROUND: Nano-biotechnology is recognized as offering revolutionary changes in the field of cancer therapy and biologically synthesized gold nanoparticles are known to have a wide range of medical applications. MATERIALS AND METHODS: Gold nanoparticles (GNPs) were biosynthesized with an aqueous extract of the red alga Corallina officinalis, used as a reducing and stabilizing agent. GNPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis (EDX) and Fourier transform infra-red (FT-IR) spectroscopy and tested for cytotoxic activity against human breast cancer (MCF-7) cells cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, considering their cytotoxicty and effects on cellular DNA. RESULTS: The biosynthesized GNPs were 14.6 ± 1 nm in diameter. FT-IR analysis showed that the hydroxyl functional group from polyphenols and carbonyl group from proteins could assist in formation and stabilization. The GNPs showed potent cytotoxic activity against MCF-7 cells, causing necrosis at high concentrations while lower concentrations were without effect as indicated by DNA fragmentation assay. CONCLUSIONS: The antitumor activity of the biosynthesized GNPs from the red alga Corallina officinalis against human breast cancer cells may be due to the cytotoxic effects of the gold nanoparticles and the polyphenolcontent of the algal extract.

Bactericidal application and cytotoxic activity of biosynthesized silver nanoparticles with an extract of the red seaweed Pterocladiella capillacea on the HepG2 cell line.

BACKGROUND: Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine. Biologically synthesized silver nanoparticles have a wide range of applications. MATERIALS AND METHODS: Silver nanoparticles (AgNPs) were biosynthesized with an aqueous extract of Pterocladiella (Pterocladia) capillacea, used as a reducing and stabilizing agent, and characterized using UV-VIS spectroscopy, Fourier Transform Infra red (FT-IR) spectroscopy, transmission electron microscopy (TEM) and energy dispersive analysis (EDX). The biosynthesized AgNPs were tested for cytotoxic activity in a human hepatocellular carcinoma (HepG2) cell line cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 1% antibiotic and antimycotic solution and 2 mM glutamine. Bacterial susceptibility to AgNPs was assessed with Staphylococcus aureus, Bacillus subtilis [Gram+ve] and Pseudomonas aeruginosa and Escherichia coli [Gram-ve]. The agar well diffusion technique was adopted to evaluate the bactericidal activity of the biosynthesized AgNPs using Ampicillin and Gentamicin as gram+ve and gram-ve antibacterial standard drugs, respectively. RESULTS: The biosynthesized AgNPs were 11.4±3.52 nm in diameter. FT-IR analysis showed that carbonyl groups from the amino acid residues and proteins could assist in formation and stabilization of AgNPs. The AgNPs showed potent cytotoxic activity against the human hepatocellular carcinoma (HepG2) cell line at higher concentrations. The results also showed that the biosynthesized AgNPs inhibited the entire panel of tested bacteria with a marked specificity towards Bacillus subtillus. CONCLUSIONS: Cytotoxic activity of the biosynthesized AgNPs may be due to the presence of alkaloids present in the algal extract. Our AgNPs appear more bactericidal against gram-positive bacteria (B. subtillus).