The role of geological origin of smectites and of their physico-chemical properties on aflatoxin adsorption

Since 2013, bentonite in the form of dioctahedral smectite is an additive authorised in the EU as a substance for the reduction of the contamination of feed by aflatoxins. Several studies indicate a big difference in the effectiveness of smectites in sequestering aflatoxins. A clear correlation between mineralogical and physico-chemical properties of smectites and aflatoxin adsorption has not been well established. In the effort to identify the most critical mineralogical, chemical, and physical properties that affect aflatoxin adsorption by smectites, 29 samples of bentonites obtained from different sources around the world were evaluated. “As received” samples were divided into two main groups, i.e. hydrothermal (n=14) and sedimentary (n=15) bentonites depending on their geological origin. The characterization studies showed that all samples contained dioctahedral smectite as major mineral; a moderate CEC value (60-116 cmol/kg); the presence of iron; a small organic matter content; a near-neutral pH; and a fine and uniform particle size (<45μm). They differed substantially in their sodium, calcium and magnesium contents, and in the swelling properties depending on the geological origin. Several in vitro adsorption studies showed that they also differed in a significant manner in adsorbing aflatoxin B1 (AFB1). A correlation between geological origin and AFB1 adsorption capacity was found (p<0.001), being sedimentary smectites significantly more effective than hydrothermal ones in adsorbing the toxin at different pH values. The extent of AFB1 adsorption by all samples was negatively and linearly correlated to the extent of desorption, and sedimentary smectites were significantly more effective than hydrothermal smectites in keeping bound the adsorbed fraction of the toxin (p < 0.001). In addition, correlation studies using the Pearson statistical method showed a significant relationship among some physico-chemical properties of smectites and the amounts of adsorbed toxin. In particular, AFB1 adsorption by smectites correlated positively with sodium content and swell index, but negatively with d001-value, magnesium and calcium contents. In conclusion, it seems that the geological origin of smectite is a useful guide for the selection of bentonites for AFB1 detoxification. Sedimentary bentonites containing sodium/swelling-smectite should be preferred to hydrothermal samples as potential aflatoxin binders. Taking into account the geographical origin of our samples, this approach should be applicable to bentonites worldwide

Virus contamination and infectivity in beach environment: Focus on sand and stranded material

To assess the exposure of beachgoers to viruses, a study on seawater, sand, and beach-stranded material was carried out, searching for human viruses, fecal indicator organisms, and total fungi. Moreover, for the first time, the genome persistence and infectivity of two model viruses was studied in laboratory-spiked sand and seawater samples during a one-week experiment. Viral genome was detected in 13.6 % of the environmental samples, but it was not infectious (Human Adenovirus – HAdV, and enterovirus). Norovirus and SARS-CoV-2 were not detected. The most contaminated samples were from sand and close to riverine discharges. In lab-scale experiments, the infectivity of HAdV5 decreased by ~1.5-Log10 in a week, the one of Human Coronavirus-229E disappeared in &lt;3 h in sand. The genome of both viruses persisted throughout the experiment. Our results confirm viral contamination of the beach and suggest HAdV as an index pathogen for beach monitoring and quantitative risk assessment

Molecular changes underlying decay of sensory responses and enhanced seizure propensity in peritumoral neurons

Background: Glioblastoma growth impacts on the structure and physiology of peritumoral neuronal networks, altering the activity of pyramidal neurons which drives further tumor progression. It is therefore of paramount importance to identify glioma-induced changes in pyramidal neurons, since they represent a key therapeutic target. Methods: We longitudinal monitored visual evoked potentials after the orthotopic implant of murine glioma cells into the mouse occipital cortex. With laser microdissection we analysed layer II-III pyramidal neurons molecular profile and with Local Field Potentials (LFP) recordings we evaluated the propensity to seizures in glioma-bearing animals with respect to control mice. Results: We determine the time course of neuronal dysfunction of glioma-bearing mice and we identify a symptomatic stage, based on the decay of visual response. At that time point, we microdissect layer II-III pyramidal neurons and evaluate the expression of a panel of genes involved in synaptic transmission and neuronal excitability. Compared to the control group, peritumoral neurons show a decrease in the expression of the SNARE complex gene SNAP-25 and the alpha1 subunit of the GABA-A receptor. No significant changes are detected in glutamatergic (i.e., AMPA or NMDA receptor subunit) markers. Further reduction of GABA-A signalling by delivery of a benzodiazepine inverse agonist, DMCM (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate) precipitates seizures in two mouse models of tumor-bearing mice. Conclusions: These studies reveal novel molecular changes that occur in the principal cells of the tumor-adjacent zone. These modifications may be therapeutically targeted to ameliorate patients' quality of life

ANKRd44 gene silencing: a putative role in trastuzumab resistance in HER2-like breast cancer

Trastuzumab is an effective therapeutic treatment for Her2-like breast cancer; despite this most of these tumors develop resistance to therapy due to specific gene mutations or alterations in gene expression. Understanding the mechanisms of resistance to Trastuzumab could be a useful tool in order to identify combinations of drugs that elude resistance and allow a better response for the treated patients. Twelve primary biopsies of Her2+/hormone receptor negative (ER-/PgR-) breast cancer patients were selected based on the specific response to neoadjuvant therapy with Trastuzumab and their whole exome was sequenced leading to the identification of 18 informative gene mutations that discriminate patients selectively based on response to treatment. Among these genes, we focused on the study of the ANKRD44 gene to understand its role in the mechanism of resistance to Trastuzumab. The ANKRD44 gene was silenced in Her2-like breast cancer cell line (BT474), obtaining a partially Trastuzumab-resistant breast cancer cell line that constitutively activates the NF-kb protein via the TAK1/AKT pathway. Following this activation an increase in the level of glycolysis in resistant cells is promoted, also confirmed by the up-regulation of the LDHB protein and by an increased TROP2 protein expression, found generally associated with aggressive tumors. These results allow us to consider the ANKRD44 gene as a potential gene involved in Trastuzumab resistance

Biodegradable plastic bags on the seafloor: A future threat for seagrass meadows?

Marine plastic litter is a global concern. Carrier bags manufactured from non-biodegradable polymers constitute a large component of this litter. Because of their adverse impact on marine life, non-biodegradable bags have recently been replaced by biodegradable ones. However, growing evidence shows that these latter are not readily degradable in marine sediments and can alter benthic assemblages. The potential impact of biodegradable bags on seagrasses inhabiting sandy bottoms,which are the mostwidespread and productive ecosystems of the coastal zones, has been ignored.Mesocosm experiments were conducted to assess the effect of a commercialized biodegradable bag on a common seagrass species of the Mediterranean, Cymodocea nodosa, both at the level of individual plant (clonal growth) and of plant community (plant-plant relationships), under three culture regimes (plant alone, in combination with a neighbour of the same species or of the co-existing seagrass Zostera noltei) simulating different natural conditions (bare substrate, monospecific meadows or mixed meadows). The bag behaviour in marine sediment and sediment physical/chemical variables were also examined. After six months of sediment exposure, the bag retained considerable mass (85% initial weight) and reduced sediment pore-water oxygen concentration and pH. In the presence of bag, C. nodosa root spread and vegetative recruitment increased compared to controls, both intra- and interspecific interactions shifted from neutral to competitive, and the growth form changed fromguerrilla (loosely arranged group ofwidely spaced ramets) to phalanx form (compact structure of closed spaced ramets) but onlywith Z. noltei. These findings suggest that biodegradable bags altering sediment geochemistry could promote the spatial segregation of seagrass clones and influence species coexistence

Biotic resistance and vegetative propagule pressure co-regulate the invasion success of a marine clonal macrophyte

Propagule pressure is considered a major driver of plant invasion success. Great propagule pressure would enable invasive species to colonize new areas overcoming the resistance of native species. Many highly invasive aquatic macrophytes regenerate from vegetative propagules, but few studies have experimentally investigated the importance of propagule pressure and biotic resistance, and their interaction, in determining invasion success. By manipulating both recipient habitat and the input of vegetative propagules of the invasive seaweed Caulerpa cylindracea in mesocosm, we examined whether higher propagule pressure would overcome the resistance of a native congeneric (Caulerpa prolifera) and influence its performance. With the native, C. cylindracea population frond number decreased irrespectively of pressure level. High propagule pressure did not increase stolon length and single plant size decreased due to the effects of intra- and interspecific competition. Native biomass decreased with increasing C. cylindracea propagule pressure. These results indicate that higher propagule pressure may fail in enhancing C. cylindracea invasion success in habitats colonized by the native species, and they suggest that biotic resistance and propagule pressure co-regulate the invasion process. These findings emphasize the need to preserve/restore native seaweed populations and may help to design effective management actions to prevent further C. cylindracea spread

Phytotoxicity assessment of conventional and biodegradable plastic bags using seed germination test

A large fraction of plastic litter found in natural environments is constituted by conventional not biodegradable plastic bags, and their adverse effects via ingestion or entanglement on terrestrial and marine organisms are largely documented. Biodegradable and compostable shoppers have been recently developed as alternative to traditional ones. These bags are specifically designed to degrade in composting facilities and generate a product devoid of toxicity to soils and crops. However, very little is known on the effects of bag leaching, i.e. the transfer of chemicals from plastic into natural environments, on vegetation. Some plant species are highly sensitive to a variety of chemicals, and seedling growth is generally the most affected life history stage. In this study we assessed the potential effects of conventional (high-density polyethylene, HDPE) and compostable (Mater-bi®, MB) bags, when left in natural environments, on water quality and plant development. To this end, seeds of Lepidium sativum L., a terrestrial plant commonly used in phytotoxicity standard tests, were exposed to leachates obtained from different amount of HDPE and MB bags, simulating various pollution degrees occurring in nature, for 72 h. Both not-exposed (or virgin) bags and natural weathering exposed bags were used. Variations of chemical-physical characteristics of extracts were used as indicative of water quality deterioration, while alterations of seed gemination and seedling radicle and hypocotyl length were considered as indicative of phytotoxicity. A chemical qualitative screening of the leachates was also performed to identify the compounds with potential phytotoxicity. Both types of bags affected water characteristics (pH, salinity and total dissolved solids) relevant to plants, and released into water intentionally added chemicals, such as the noxious bisphenol A, and other phytotoxic substances probably generated during bag manufacturing. Leachates from both bag types did not affect seed germination. But, a significant number of seedlings showed developmental abnormalities or reduced seedling growth. The hypocotyl was the most sensible seedling organ to HDPE bag leachates while the radicle was the most vulnerable to MB ones. These findings indicate that plastic bags, including those that meet biodegradability and compostability standards, represent a potential threat to plants, if left in natural environments. Therefore, people and managers should be adequately informed about the potential environmental impact of an incorrect bag disposal. Simple, rapid standard phytotoxicity tests, such as the L. sativum bioassay, applied to bag leachates could be used in the future to select not noxious additives so to develop more eco-friendly bags

Early evidence of the impacts of microplastic and nanoplastic pollution on the growth and physiology of the seagrass Cymodocea nodosa

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous in natural habitats and the risks their presence poses to marine environments and organisms are of increasing concern. There is evidence that seagrass meadows are particularly prone to accumulate plastic debris, including polystyrene particles, but the impacts of this pollutant on seagrass performance are currently unknown. This is a relevant knowledge gap as seagrasses provide multiple ecosystem services and are declining globally due to anthropogenic impact and climate-change-related stressors. Here, we explored the potential effects of a 12 day-exposure of seagrasses to one concentration (68 μg/L) of polystyrene MPs and NPs on the growth, oxidative status, and photosynthetic efficiency of plants using the foundation species Cymodocea nodosa as a model. Among plant organs, adventitious roots were particularly affected by MPs and NPs showing complete degeneration. The number of leaves per shoot was lower in MPs- and NPs-treated plants compared to control plants, and leaf loss exceeded new leaf production in MPs-treated plants. MPs also reduced photochemical efficiency and increased pigment content compared to control plants. Shoots of NPs-treated plants showed a greater oxidative damage and phenol content than those of control plants and MPs-treated plants. Biochemical data about oxidative stress markers were consistent with histochemical results. The effects of MPs on C. nodosa could be related to their adhesion to plant surface while those of NPs to entering tissues. Our study provides the first experimental evidence of the potential harmful effects of MPs/NPs on seagrass development. It also suggests that the exposure of seagrasses to MPs/NPs in natural environments could have negative consequences on the functioning of seagrass ecosystems. This stresses the importance of implementing cleaning programs to remove all plastics already present in marine habitats as well as of undertaking specific actions to prevent the introduction of these pollutants within seagrass meadows

Leached degradation products from beached microplastics: A potential threat to coastal dune plants

Plants play a fundamental role in maintaining coastal dunes but also accumulate littered microplastics (MPs). Migration tests suggest that naturally weathered MPs can leach out a broader range of potentially phytotoxic chemicals than virgin MPs. Thus, assessing MPs effects on plants using beached-collected particles rather than virgin ones is critically important. Here, the effects on plants of leachates from two pools of beach-collected and virgin MPs, high-density polyethylene (HDPE) and polypropylene (PP), and their mixture, were explored combining toxicity tests and chemical analyses. Phytotoxicity of MP leachates at different dilutions was evaluated under standard laboratory conditions using test species and under environmentally realistic conditions using the dune species Thinopyrum junceum. Leachates from beached PP and HDPE adversely affected all species, and the extent of these effects varied according to polymer type, concentration, and species. Virgin MPs had weaker effects than beached ones. Several potentially phytotoxic oxidized compounds were detected in water by GC/MS analysis, and their amount estimated. Results indicate that the molecular species leaching from beached MPs - at ppm concentration levels for the individual chemical species - can inhibit plant growth, and the effects of leachates from mixtures of degraded MPs can differ from those from individual polymers, highlighting the need for further investigation of MPs consequences for coastal ecosystems

Beach pollution from marine litter: Analysis with the DPSIR framework (driver, pressure, state, impact, response) in Tuscany, Italy

Beaches are affected by the accumulation of natural and anthropogenic material; however, this environmental issue has not yet been explored from a One Health perspective. In this paper, the conceptual framework of DPSIR (Drivers-Pressures-State-Impact-Response) was used to understand the beach-stranded material issue in a systemic way and a data-based classification for some environmental indicators was developed to support the DPSIR analysis. The model was applied to an Italian coastal municipality as a case study, through the collection of data from a variety of data sources: publicly accessible database, data from a stakeholders’ network (i.e., coastal authority, solid waste company, sewerage company, drainage consortium), and fieldwork consisting in microbiological analysis of stranded material and underlying sand, visual census of macrolitter along beach and waterways. In the study area, solid wastes production was a high pressure (768&nbsp;kg/capita/year), but in situ visual observations of floating wastes at the outlet of the canals revealed that the contribution of local waterways to marine litter was negligible, thus suggesting the effectiveness of the measures adopted along local waterways by the drainage consortium (i.e., grids at the drainage pumping stations). Nevertheless, very high quantity of anthropogenic wastes was counted during the beach litter surveys (603 items/100&nbsp;m), probably as a result of coastal current pathway that transported material from major watercourses (&gt;100&nbsp;km2 drainage basin size; 23 items/h). On the contrary, local sewage production represented a very high pressure (&gt;33,000&nbsp;m3/km) that impacted on the microbiological quality of the stranded material with moderate to high level of fecal bacteria indicators detected in the beach cast. The underlying sand was affected by such contamination, with most of the sample within the provisional limit set by WHO for enterococci in beach sand (60&nbsp;CFU/g) that was associated to a health risk of&lt;5&nbsp;% of gastroenteritis attributable to accidental ingestion of sand; nevertheless, some enterococci peak values (980 MPN/g) could be associated to a health risk for gastroenteritis&gt;10&nbsp;%. The beach-stranded material was collected without separating the sand, with annual quantity of 1,243&nbsp;kg/m, that was processed in a dedicated facility allowing to recover up to 98&nbsp;% of sand and biomass after the treatment, with moderate expenditure for the coastal municipality (22 €/m). Overall, this study allowed to better figure out the cause-effect relationships underlying the accumulation of stranded material along shoreline and the effectiveness of the management practices toward beach-stranded material. Therefore, the usage of the DPSIR framework as structuring model to understand the problem of stranded material could be useful for beach managers and administrators, and its adoption within beach management programs is worth for improving beach quality