Microplastics (MP) are detected in aquatic environments worldwide, yet detection is often limited to larger sized MP. To address this data gap, the abundance of MP 3–500 μm was assessed in the Los Angeles River, the San Gabriel River, and the Long Beach Harbor (CA, USA), three areas with highly urbanized surroundings. Whole surface water samples were taken, subjected to a hydrogen peroxide digestion and MP counts were compared between unstained visual examination and Nile Red staining identification techniques. The largest concentration of MP was found in the Los Angeles River, where 13,622 MP m−3 were found using unstained visual examination and 641,292 MP m−3 were found utilizing Nile Red staining. The protocol used to detect smaller sized MP is low cost, time efficient, and reproducible. This work highlights the need for more extensive sampling of smaller sized MP globally and universal testing and reporting standards for MP detection.

Shipping is recognised as an unintentional efficient pathway for spreading non-native species, harmful organisms and pathogens. In 2004, a unique IMO Convention was adopted to control and minimize this transfer in ship's ballast water. This Convention entered into force on 8th September 2017. However, unlikely the majority of IMO Conventions, the Ballast Water Management Convention requires ships to comply with biological standards (e.g. concentration of organisms per unit of volume in ballast water discharges). This study aimed to apply different techniques developed to measure concentrations of viable phytoplankton in natural and treated ballast water samples and compare them with the established flow cytometry method and vital staining microscopy. Samples were collected in the English Channel over one year and on-board during ballast water shipboard efficacy tests. Natural abundance of live phytoplankton varied from 23% to 89% of the total, while for cells larger than 10 μm (a size defined by the BWM Convention) the percentage varied from 3% to 60%. An overall good correlation was seen between the measurements taken with the two fluorometers and in comparison with the flow cytometry analysis, as found in previous studies. Analysis of treated ballast water samples showed a large variation in the number of viable cells, however indicating a low level of risk on all occasions for regulatory purposes. One of the key aspects to bear in mind when sampling and analysing for compliance is to be aware of the limitations of each technique.

The invasive mussel Xenostrobus securis was recorded for the first time in the Galician Rias Baixas (NW Spain) in 2007, within an area characterized by intense commercial culture of Mytilus galloprovincialis. The main aims of this study were to evaluate whether an immunological assay can be used to detect larvae of this species in field samples of plankton and to determine whether the distribution of larvae matched that of adults. The ability of two monoclonal antibodies to recognize the bivalve was tested by immunofluorescence. Only the M22.8 antibody recognized X. securis larvae. The staining pattern distinguished X. securis from M. galloprovincialis larvae in both laboratory cultures and field samples of plankton. The distribution of larvae did not match that of adults. This tool may prove very useful for monitoring the presence of this invasive species in the plankton, allowing rapid and specific recognition.

We investigated the applicability of Nile Red (NR), a fluorescent dye, for microplastic analysis, and determined the optimal staining conditions. Five mg/L NR solution in n-hexane effectively stained plastics, and they were easily recognized in green fluorescence. The NR staining method was successfully applied to micro-sized polyethylene, polypropylene, polystyrene, polycarbonate, polyurethane, and poly(ethylene-vinyl acetate), except for polyvinylchloride, polyamide and polyester. The recovery rate of polyethylene (100–300μm) spiked to pretreated natural sand was 98% in the NR stating method, which was not significantly (p<0.05) different with FT-IR identification. The NR staining method was suitable for discriminating fragmented polypropylene particles from large numbers of sand particles in laboratory weathering test samples. The method is straightforward and quick for identifying and quantifying polymer particles in the laboratory controlled samples. Further studies, however, are necessary to investigate the application of NR staining to field samples with organic remnants.

Extensive use of aluminum (Al) in industry, cooking utensils, and wrapping or freezing the food items, due to its cheapness and abundance in the environment, has become a major concern. Growing evidence supports that environmental pollutant Al promotes the aggregation of amyloid beta (Aβ) in the brain, which is the main pathological marker of Alzheimer’s disease (AD). Further, AD- and Al-induced neurotoxic effects are more common among women following reproductive senescence due to decline in estrogen. Though clinically Ginkgo biloba extract (GBE) has been exploited as a memory enhancer, its role in Al-induced neurotoxicity in reproductive senescent female rats needs to be evaluated. Animals were exposed to intraperitoneal dose (10 mg/kg b.wt) of Al and oral dose (100 mg/kg b.wt.) of GBE daily for 6 weeks. A significant decline in the Al-induced Aβ aggregates was observed in hippocampal and cortical regions of the brain with GBE supplementation, as confirmed by thioflavin (ThT) and Congo red staining. GBE administration significantly decreased the reactive oxygen species, lipid peroxidation, nitric oxide, and citrulline levels in comparison to Al-treated rats. On the contrary, a significant increase in the reduced glutathione, GSH/GSSG ratio as well as in the activities of antioxidant enzymes was observed with GBE administration. Based on the above results, GBE prevented the neuronal loss in the hippocampus and cortex, hence caused significant improvement in the learning and memory of the animals in terms of AChE activity, serotonin levels, Morris water maze, and active and passive avoidance tests. In conclusion, GBE has alleviated the behavioral, biochemical, and histopathological alterations due to Al toxicity in rats. However, molecular studies are going on to better understand the mechanism of GBE protection against the environmental toxicant Al exposure. Graphical abstract .

Accumulation of divalent manganese (Mn) and its toxicity in the green alga Scenedesmus quadricauda was studied at circumneutral pH (6.5). A comparison of two applied concentrations (10 or 100 μM) of MnCl₂, MnSO₄, and Mn(NO₃)₂ indicated that mainly sulfate evoked higher Mn accumulation. On the other hand, nitrate rather depleted antioxidative enzyme activities (APX, CAT, SOD), leading to an increase in ROS formation as proven by fluorescence microscopy. Subsequent experiments revealed that increase in pH (from 4.5 to 9.5) increased also Mn content but typically depleted amounts of reduced glutathione and phytochelatin 2. We also measured the size of particles formed from the manganese salts at pH 9.5. Competitive experiment between Ca/K salts (CaCl₂, CaSO₄, Ca(NO₃)₂, KCl, K₂SO₄, KNO₃) and Mn (as Mn sulfate) showed a negative relation between Ca and Mn amount but KNO₃ stimulated Mn accumulation. Microscopy revealed that mainly K salts elevated plasma membrane damage (Acridine orange staining). Data indicate that not only pH but also accompanying anion affects Mn accumulation and that Ca salts may affect Mn toxicity.

Multiple drug resistance and increased side effects due to allopathic drugs has warned scientific community with a global alarm to identify molecules from natural sources to combat diseases with minimum or no side effects. The present investigation was aimed to identify and isolate secondary metabolites from traditionally used Nerium indicum using conventional column chromatography which led to the isolation of two compounds, C-I (fractions NB4f1) and C-II (fractions NC13b1). Further characterized, it is elucidated using spectral data and identified as N-(4-hydroxy-phenyl)-2-methoxy-2-phenyl-acetamide, molecular formula C₁₅H₁₅NO₃, and molecular weight 257.3 (C-I) and N-(4-hydroxy-phenyl)-2-phenyl-N-phenylacetyl-acetamide, molecular formula C₂₂H₁₉NO₃, and molecular weight 345.4 (C-II). Further, the isolated compounds were investigated using in silico approach by Autodock tool with four different proteins specific for cancer and in vitro assessed cell proliferation, and apoptosis against human breast cancer MCF 7 cell line. The results of the in silico model demonstrated potent binding affinity of both compounds with the proteins representing that the isolated molecules could be a drug of choice for cancer. Further, the isolated compounds revealed significant inhibition of cell proliferation (IC₅₀ values 21 μg/mL for C-I, 19 μg/mL for C-II) with induced apoptosis with nuclear condensation effect on the MCF 7 cells in in vitro condition even at very low concentration. Compound treatment to MCF-7 cell line represented bright fetches indicating condensed chromatins and higher level of nuclear fragmentation with DAPI staining, indicating higher cell death due to induced apoptosis and confirmed using flow cytometry analysis representing inhibition of cell proliferation at S phase. Graphical abstract

The present study deals with the synthesis of silver nanoparticles (AgNPs) from Rhynchosia rufescens and to evaluate its cytotoxic effect mediated through induced apoptosis. The reduction and capping of phytoconstituents was confirmed using FTIR demonstrating O–H and C–H stretching at different peaks. The size and the shape of the particle were determined using scanning electron microscopy (SEM) illustrating 1 μm to 100 nm in size and the composition of compounds in the AgNPs were revealed using XRD and EDX. The results of the antioxidant assays revealed that the synthesized AgNPs had significant radical scavenging potential in dose-dependent inhibition with 22–64% for DPPH and 25–41% for ferric reducing antioxidant power assay at the concentrations of 20–100 μg/ml. Further, the synthesized AgNPs demonstrated potent cytotoxic activity against human breast cancer (MCF-7) cell line with an IC₅₀ value of 26 ± 1.0 μg/ml by the MTT assay. Cytotoxicity was confirmed using AO/EtBr and DAPI staining method where nuclear condensation and fragmentation of cancer cells was observed after treatment with nanoparticle. The results were further confirmed by flow cytometry analysis which revealed the occurrence of apoptosis during the S phase in cell cycle exposing the potential of the AgNPs against MCF-7 cancer cell. From the results, we conclude that the synthesized AgNPs from Rhynchosia rufescens exhibited multifunctional properties. Graphical abstract

This paper presents the oil-suspended particulate matter aggregate (OSA) resulted from the interaction of droplets of dispersed oil in a water column and particulate matter. This structure reduces the adhesion of oil on solid surfaces, promotes dispersion, and may accelerate degradation processes. The effects of the addition of fine sediments (clay + silt) on the formation of OSA, their impact on the dispersion and degradation of the oil, and their potential use in recovering reflective sandy beaches were evaluated in a mesoscale simulation model. Two simulations were performed (21 days), in the absence and presence of fine sediments, with four units in each simulation using oil from the Recôncavo Basin. The results showed that the use of fine sediment increased the dispersion of the oil in the water column up to four times in relation to the sandy sediment. There was no evidence of the transport of hydrocarbons in bottom sediments associated with fine sediments that would have accelerated the dispersion and degradation rates of the oil. Most of the OSA that formed in this process remained in the water column, where the degradation processes were more effective. Over the 21 days of simulation, we observed a 40 % reduction on average of the levels of saturated hydrocarbons staining the surface oil.

The present study aimed to determine the level of iron and calcium in the seminal plasma of men with different fertility potentials and to examine its relationship with oxidative stress. Seventy-nine sub-fertile patients with asthenoteratozoospermia (AT), n 27; teratoleucozoospermia (TL), n 20; teratozoospermia (Terato), n 32; and 29 healthy donors were included. The ability of spermatozoa to produce reactive oxygen species (ROS) was evaluated by using nitroblue tetrazolium (NBT) staining. The lipid peroxidation end product, malondialdehyde (MDA), and the trace element levels (iron and calcium) were measured spectrophotometrically. Iron and calcium concentrations in seminal plasma of the patient groups were significantly more elevated than the normal group. Nevertheless, both calcium and iron showed strong negative correlations with the total sperm motility and normal sperm morphology, but only iron was positively and significantly associated with multiple anomalies index and seminal leucocyte concentration. On the other hand, the rates of MDA and ROS production in semen were significantly higher in the three abnormal groups than in controls. These two oxidative stress biomarkers were significantly associated with the percentage of atypical forms in semen. However, only semen ROS level was significantly associated with the decreased sperm motility and the sperm leucocytes concentration. Meanwhile, there are positive correlations between seminal iron and calcium content and the studied oxidative stress biomarkers. Oxidative stress and trace element excess are implicated in low sperm quality. Iron and calcium might be the mediators of the effects of oxidative damage and induces lipid peroxidation.