No abstract

The problem of drug resistance is very worrying and ever increasing. Resistance is due not only to the reckless use of antibiotics but also to the fact that pathogens are able to adapt to different conditions and develop self-defense mechanisms such as living in biofilms; altogether these issues make the search for alternative drugs a real challenge. Antimicrobial peptides appear as promising alternatives but they have disadvantages that do not make them easily applicable in the medical field; thus many researches look for solutions to overcome the disadvantages and ensure that the advantages can be exploited. This review describes the biofilm characteristics and identifies the key features that antimicrobial peptides should have. Recalcitrant bacterial infections caused by the most obstinate bacterial species should be treated with a strategy to combine conventional peptides functionalized with nano-tools. This approach could effectively disrupt high density infections caused by biofilms. Moreover, the importance of using in vivo non mammalian models for biofilm studies is described. In particular, here we analyze the use of amphibians as a model to substitute the rodent model.

Nanostructured ZnO seems to exert a higher toxic effect in insoluble form towards different terrestrial organisms with respect to similar amounts of zinc in ionic form.

Nano-based products are widespread in several sectors, including textiles, medical-products, cosmetics, paints and plastics. Nanosafety and safe-by-design are driving nanoparticle (NP) production and applications through NP functionalization (@NPs). Indeed, @NPs frequently present biological effects that differ from the parent material. This paper reviews the impact of quantum dots (QDs), gold nanoparticles (AuNPs), and polystyrene-cored NPs (PSNPs), evidencing the role of NP functionalization in toxicity definition. Key biological models were taken into consideration for NP evaluation: Saccharomyces cerevisiae, fresh- (F) and saltwater (S) microalgae (Raphidocelis subcapitata (F), Scenedesmus obliquus (F) and Chlorella spp. (F), and Phaeodactylum tricornutum (S)), Daphnia magna, and Xenopus laevis. QDs are quite widespread in technological devices, and they are known to induce genotoxicity and oxidative stress that can drastically change according to the coating employed. For example, AuNPs are frequently functionalized with antimicrobial peptides, which is shown to both increase their activity and decrease the relative environmental toxicity. P-NPs are frequently coated with NH2− for cationic and COOH− for anionic surfaces, but when positively charged toxicity effects can be observed. Careful assessment of functionalized and non-functionalized NPs is compulsory to also understand their potential direct and indirect effects when the coating is removed or degraded.

New Findings r What is the central question of this study?In humans, 'Western-style' diet is characterized by high levels of both saturated fats and fructose. Lipid oversupply to the liver typical of high-fat diets could be exacerbated by the coexistence of high levels of fat and fructose in the diet, thus accelerating the development of metabolic deregulation. r What is the main finding and its importance?Short-term consumption of a Western diet, rich in saturated fats and fructose, is more conducive to the development of liver steatosis and deleterious to glucose homeostasis than a high-fat diet. This result points to the harmful effect of adding fructose to the usual Western, high-fat diet.The purpose of the present study was to examine the short-term effect of high-fat or high-fat-high-fructose feeding on hepatic lipid metabolism and mitochondrial function in adult sedentary rats. Adult male rats were fed a high-fat or high-fat-high-fructose diet for 2 weeks. Body and liver composition, hepatic steatosis, plasma lipid profile and hepatic insulin sensitivity, together with whole-body and hepatic de novo lipogenesis, were assessed. Hepatic mitochondrial mass, functionality, oxidative stress and antioxidant defense were also measured. Rats fed the high-fat-high-fructose diet exhibited significantly higher plasma triglycerides, non-esterified fatty acids, insulin and indexes of hepatic insulin resistance compared with rats fed a low-fat or a high-fat diet. Hepatic triglycerides and ceramide, as well as the degree of steatosis and necrosis, were significantly higher, while liver p-Akt was significantly lower, in rats fed high-fat-high-fructose diet than in rats fed high-fat diet. A significant increase in non-protein respiratory quotient and hepatic fatty acid synthase and stearoyl CoA desaturase activity was found in rats fed the high-fat-high-fructose diet compared with those fed the high-fat diet. Significantly lower mitochondrial oxidative capacity but significantly higher oxidative stress was found in rats fed high-fat and high-fat-high-fructose diets compared with rats fed low-fat diet, while mitochondrial mass significantly increased only in rats fed high-fat-high-fructose diet. In conclusion, short-term consumption of a Western diet, rich in saturated fats and fructose, is more conducive to the development of liver steatosis and deleterious to glucose homeostasis than a high-fat diet.