Assessment of domestic water quality of households and schools in Nabatieh, Lebanon, and development of a new spectrophotometric method for the detection of Entamoeba spp. In tap water.

Polluted resources of potable water are daily used for different purposes in Lebanon. The optical microscopy is the traditional method used for the detection of Entamoeba spp. in water despite its weak sensitivity. We aimed to characterize domestic water at Nabatieh district, South Lebanon, and to develop a simple method for Entamoeba spp. detection. A total of 70 water samples were collected from houses and schools and analyzed for physical (pH, total dissolved solids and temperature), chemical (nitrate, phosphate and sulfate) and bacterial (total and fecal coliforms) parameters. The contamination by Entamoeba spp. was examined using microscopy, then a spectrophotometric wavelength scan was recorded for 50 samples in order to determine the common peak between positive samples. High phosphate levels were detected in all the samples, with important bacterial and parasitological contaminations. The spectrophotometric analyses showed a peak repetition at the wavelength of 696 nm in the spectrum of the majority of positive samples. The number of cysts was significantly correlated to optical densities at 696 nm (R = 0.9087; p-value<0.0001). The regression analysis showed that the OD696 could statistically predict the concentration (F (1,48) = 267.02, p-value <0.001). In conclusion, potable water parameters at Nabatieh district did not meet the national and international guidelines of safe drinking water, and the detection of Entamoeba spp. cysts in potable water can be performed using a rapid spectrophotometric analysis, by the determination of the optical density at 696 nm and the application of a specific equation.

Assessing the effects of nickel on, e.g., Medicago sativa L. nodules using multidisciplinary approach.

Industrial wastes and fertilizers can introduce excessive levels of nickel (Ni) into the environment, potentially causing threats to plants, animals, as well as human beings. However, the number of studies on the effects of Ni toxicity on nodules is fairly limited. To address this issue, the effects of increasing Ni concentration on alfalfa nodules were assessed at chemical, biochemical, and transcriptomic levels. For this purpose, plants were grown in soils supplied with Ni (control, 0 mg/kg; C1, 50 mg/kg; C2, 150 mg/kg; C3, 250 mg/kg; and C4, 500 mg/kg) for 90 days. Ni loads in leaves, roots, and nodules were monitored after the exposure period. A set of biochemical biomarkers of oxidative stress was determined in nodules including antioxidants and metal homeostasis as well as lipid peroxidation. Gene expression levels of the main targets involved in oxidative stress and metal homeostasis were assessed. Our data indicated a high concentration of Ni in leaves, roots, and nodules where values reached 25.64 ± 3.04 mg/kg, 83.23 ± 5.16 mg/kg, and 125.71 ± 4.53 mg/kg in dry weight, respectively. Moreover, a significant increase in nodule biomass was observed in plants exposed to C4 in comparison to control treatment and percentage increased by 63%. Then, lipid peroxidation increased with a rate of 95% in nodules exposed to C4. Enzymatic activities were enhanced remarkably, suggesting the occurrence of oxidative stress, with increased superoxide dismutase (SOD), glutathione reductase (GR), and ascorbate peroxidase (APX). Our results showed also a significant upregulation of SOD, GR and APX genes in nodules. Nodule homoglutathione (HGSH) levels increased with the different Ni concentrations, with a remarkable decrease of glutathione S-transferase (GST) activity and glutathione (GSH) content for the highest Ni concentration with 43% and 52% reduction, respectively. The phytochelatin (PC) and metallothionein (MT) concentrations increased in nodules, which implied the triggering of a cellular protection mechanism for coping with Ni toxicity. The results suggested that Ni promotes a drastic oxidative stress in alfalfa nodules, yet the expression of MT and PC to reduce Ni toxicity could be used as Ni stress bioindicators. Our findings provide new insights into the central role of alfalfa nodules in limiting the harmful effects of soil pollution. Therefore, nodules co-expressing antioxidant enzymes may have high phytoremediation potential.

Autophagic event and metabolomic disorders unveil cellular toxicity of environmental microplastics on marine polychaete Hediste diversicolor.

Although the hazards of microplastics (MPs) have been quite well explored, the aberrant metabolism and the involvement of the autophagy pathway as an adverse response to environmental MPs in benthic organisms are still unclear. The present work aims to assess the impact of different environmental MPs collected from the south coast of the Mediterranean Sea, composed by polyethylene (PE), polyethylene vinyl acetate (PEVA), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and polyamide (PA) on the metabolome and proteome of the marine polychaete Hediste diversicolor. As a result, all the microplastic types were detected with Raman microspectroscopy in polychaetes tissues, causing cytoskeleton damage and induced autophagy pathway manifested by immunohistochemical labeling of specific targeted proteins, through Tubulin (Tub), Microtubule-associated protein light chain 3 (LC3), and p62 (also named Sequestosome 1). Metabolomics was conducted to further investigate the metabolic alterations induced by the environmental MPs-mixture in polychaetes. A total of 28 metabolites were differentially expressed between control and MPs-treated polychaetes, which showed elevated levels of amino acids, glucose, ATP/ADP, osmolytes, glutathione, choline and phosphocholine, and reduced concentration of aspartate. These novel findings extend our understanding given the toxicity of environmental microplastics and unravel their underlying mechanisms.

Assessing the presence of microplastic particles in Tunisian agriculture soils and their potential toxicity effects using Eisenia andrei as bioindicator.

In the present study, we investigated microplastics (MPs) in agricultural soils with different agronomic practices (organic farming, soil under greenhouses, soil under mulching and soil irrigated with treated wastewater (TWW)). Plastic particles from each site were collected and characterized by FTIR and Raman microspectroscopy. Plastic particles were then ground and added (size rage under 100 µm) at a concentration of 100 µg kg-1 to soils from organic farming containing Eisenia andrei for 7 and 14 days. MPs accumulation in earthworms was quantified and characterized. Oxidative stress was assessed by evaluating the activities of catalase, glutathione-S-transferase, and acetylcholinesterase as well as malondialdehyde accumulation. Our results revealed higher quantity of MPs in soils ranging from 13.21 ± 0.89 to 852.24 ± 124.2 items kg-1 with the dominance of small sizes (0.22-1.22 µm). Polyethylene (PE) and polybutyrate adipate terephtalate (PBAT) were the dominant MPs. Moreover, our results revealed a significant ingestion of MPs in earthworms with values ranging from 1.13 to 35.6, characterized mostly by PE, PBAT and polypropylene (PP). Biochemical data revealed an important alteration in worms exposed to MPs from soils with mulching and irrigated with TWW. Our study provides new insights into the effects of microplastic in earthworms and thus the vulnerability of terrestrial ecosystem to this emergent contaminant.

Uptake, accumulation and associated cellular alterations of environmental samples of microplastics in the seaworm Hediste diversicolor.

The ubiquitous distribution of microplastics (MPs) in the marine environment raises global concern to understand their impact. Environmental MPs have been shown to exhibit different physicochemical properties during their life cycles. However, the body of knowledge regarding their accumulation and biological effects is still significantly limited compared to manufactured MPs. To evaluate the hazardous effects of a mixture of environmental MPs collected along the Tunisian beaches, their accumulation and cellular effects were investigated in Hediste diversicolor. MP sample was composed of polyethylene (PE), polyethylene vinyl acetate (PEVA), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and polyamide (PA) analyzed using Raman microspectroscopy (RM). The concentrations of MPs in seaworm tissues increased over time, following the order 1.2-0.45 µm > 3-1.2 µm > 100-3 µm. The ingestion of MPs by H. diversicolor reduced their survival and growth, affected the neuro-transmission and antioxidant pathways. Our data emphasised that the toxic effects of environmental MPs were closely related to the exposure dose and period. The results also demonstrated that the size distribution of MPs in seaworms was mainly correlated with biochemical markers. This study highlights the ecological risk in the ingestion and accumulation of environmental MPs by biota that threatens their functional parameters.

Fabrication of large pore mesoporous silica microspheres by salt-assisted spray-drying method for enhanced antibacterial activity and pancreatic cancer treatment.

Large-pore mesoporous silica (LPMS) microspheres with tunable pore size have received intensive interest in the field of drug delivery due to their high storage capacity and fast delivery rate of drugs. In this work, a facile salt-assisted spray-drying method has been developed to fabricate LPMS microspheres using continuous spray-drying of simple inorganic salts as pore templates and colloidal SiO2 nanoparticles as building blocks, followed by washing with water to remove the templates. More importantly, the porosity of the LPMS microspheres can be finely tuned by adjusting the furnace temperature and relative concentration of the salt to SiO2, which could lead to optimal pharmaceutical outcomes. Then, the biological roles of these LPMS microspheres were evaluated in antibacterial and cancer therapy. In this regard, rhodamine b as a probe was initially loaded inside the LPMS microspheres. The obtained particles not only showed high entrapment efficiency (up to 30%) and a pH-responsive drug release but also presented pore-size-controlled drug release performance. Then, in vitro antibacterial activities of multiple antibiotics, namely nalidixic acid, chloramphenicol, and ciprofloxacin, loaded in the LPMS particles were investigated against two pathogenic bacteria, Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The results indicated bacterial inhibition up to 70% and 20% in less than 2 h for Escherichia coli and Staphylococcus aureus, respectively. This inhibition of bacterial growth was accompanied by no bacterial regrowth within 30 h. Finally, the versatility of LPMS microspheres as drug carriers in pancreatic cancer treatment was explored. In this regard, a pro-apoptotic NCL antagonist agent (N6L) as an antitumor agent was successfully loaded onto LPMS microspheres. Interestingly, the resulting particles showed pore-size-dependent anticancer activity with inhibition of cancer cell growth up to 60%.

Physiological, biochemical and transcriptomic responses of Medicago sativa to nickel exposure.

Metal accumulation in soil could lead to severe damage to plants, animals, and humans. The present work aims to evaluate the effects of nickel (Ni) exposure on Medicago sativa at physiological, biochemical, and transcriptomic levels. Plants were exposed to five increasing concentrations of Ni (0, 50, 150, 250, and 500 mg/kg) for 60 days. Agronomic parameters (fresh and dry matter) and chlorophyll content (Chl) were determined in an alfalfa plant. Chemical analyses were conducted, involving the determination of Ni loads in plants (roots and shoots). Moreover, malondialdehyde accumulation (MDA), glutathione-S-transferase (GST), and peroxidase activities, termed as oxidative stress biomarkers, were measured. The gene expression levels of Prx1C, GST, and phytochelatins (PCs) were determined at different nickel concentrations. Our results showed that Ni concentration in plants increased significantly along with Ni concentration in the soil. Regarding oxidative stress biomarkers, Ni contamination caused an increase in peroxidase and GST activities, with a remarkable accumulation of MDA, especially for the highest Ni concentration (500 mg/kg of Ni). Our data showed also a significant upregulation of Prx1C and GST genes in shoots and roots. The PCs' gene expression was significantly enhanced in response to the different nickel concentrations, suggesting their important role in Ni detoxification in alfalfa plants. Our data provided evidence about the clear toxicity of Ni, an often-underestimated trace element.

Aerosol-Assisted Synthesis of Tailor-Made Hollow Mesoporous Silica Microspheres for Controlled Release of Antibacterial and Anticancer Agents.

Hollow mesoporous silica microsphere (HMSM) particles are one of the most promising vehicles for efficient drug delivery owing to their large hollow interior cavity for drug loading and the permeable mesoporous shell for controlled drug release. Here, we report an easily controllable aerosol-based approach to produce HMSM particles by continuous spray-drying of colloidal silica nanoparticles and Eudragit/Triton X100 composite (EUT) nanospheres as templates, followed by template removal. Importantly, the internal structure of the hollow cavity and the external morphology and the porosity of the mesoporous shell can be tuned to a certain extent by adjusting the experimental conditions (i.e., silica to EUT mass ratio and particle size of silica nanoparticles) to optimize the drug loading capacity and the controlled-release properties. Then, the application of aerosol-synthesized HMSM particles in controlled drug delivery was investigated by loading amoxicillin as an antibiotic compound with high entrapment efficiency (up to 46%). Furthermore, to improve the biocompatibility of the amoxicillin-loaded HMSM particles, their surfaces were functionalized with poly(allylamine hydrochloride) and alginate as biocompatible polymers via the layer-by-layer assembly. The resulting particles were evaluated toward Escherichia coli (Gram-negative) bacteria and indicated the bacterial inhibition up to 90% in less than 2 h. Finally, we explored the versatility of HMSMs as drug carriers for pancreatic cancer treatment. Because the pH value of the extracellular medium in pancreatic tumors is lower than that of the healthy tissue, chitosan as a pH-sensitive gatekeeper was grafted to the HMSM surface and then loaded with a pro-apoptotic NCL antagonist agent (N6L) as an anticancer drug. The obtained particles exhibited pH-responsive drug releases and excellent anticancer activities with inhibition of cancer cell growth up to 60%.