Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

Bovine mastitis (BM) is the most prevalent bacterial infection in the livestock sector, affecting the dairy industry greatly. The prevention and treatment of this disease is mainly made via antibiotics, but the increasing antimicrobial resistance of pathogens has affected the efficiency of conventional drugs. Pseudomonas sp. is one of the pathogens involved in this infection. The therapeutic rate of cure for this environmental mastitis-causing pathogen is practically zero, regardless of treatment. Biofilm formation has been one of the main virulence mechanisms of Pseudomonas hence presenting resistance to antibiotic therapy. We have manufactured chitosan nanoparticles (NQo) with tripolyphosphate (TPP) using ionotropic gelation. These NQo were confronted against a Pseudomonas sp. strain isolated from milk samples of cows diagnosed with BM, to evaluate their antimicrobial and antibiofilm capacity. The NQo showed great antibacterial effect in the minimum inhibitory concentrations (MIC), minimum bactericidal concentration (MBC) and disk diffusion assays. Using sub lethal concentrations, NQo were tested for inhibition of biofilm formation. The results show that the nanoparticles exhibited biofilm inhibition and were capable of eradicate pre-existing mature biofilm. These findings indicate that the NQo could act as a potential alternative to antibiotic treatment of BM.

Background/Objectives: Bovine mastitis (BM), a prevalent and economically burdensome bacterial infection affecting dairy cattle, poses a significant challenge to the dairy industry. The traditional approach to combating BM, relying heavily on antibiotics, faces growing concerns due to the increasing antibiotic resistance exhibited by pathogens. The objective of this study was to evaluate and determine the antimicrobial and anti-biofilm potential of chitosan nanoparticles (NQo) on S. aureus strains isolated from milk samples obtained from dairy areas in southern Chile from cows diagnosed with BM. Methods: NQo were synthesized using the ionotropic gelation method and thoroughly characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Results: The NQo exhibit a robust positive charge (Z-potential of +55.4 ± 2.5 mV) and an exceptionally small size (20.3 ± 3.2 nm). This unique combination of properties makes NQo particularly well-suited for targeting and interacting with bacterial pathogens. To assess the effectiveness of NQo against BM, we conducted a series of experiments using a Staphylococcus aureus strain isolated from milk samples of cows diagnosed with BM in southern Chile. NQo demonstrated a remarkable ability to inhibit bacterial proliferation and effectively modulate biofilm formation in the S. aureus strains. Furthermore, the performance of NQo in comparison to established antibiotics like ampicillin and gentamicin strongly suggests that these nanoparticles hold immense potential as an attractive alternative for the control, prevention, and/or treatment of BM. Conclusions: NQo exhibit both antimicrobial and antibiofilm activity against a clinically relevant BM pathogen. Further investigations are necessary to develop a hydrogel formulation optimized for effective delivery to the target diseased tissue.

Due to the inability to curb the excessive increase in the prevalence of obesity and overweight, it is necessary to comprehend in more detail the factors involved in the pathophysiology and to appreciate more clearly the biochemical and molecular mechanisms of obesity. Thus, understanding the biological regulation of adipose tissue is of fundamental relevance. Connexin, a protein that forms intercellular membrane channels of gap junctions and unopposed hemichannels, plays a key role in adipogenesis and in the maintenance of adipose tissue homeostasis. The expression and function of Connexin 43 (Cx43) during the different stages of the adipogenesis are differentially regulated. Moreover, it has been shown that cell–cell communication decreases dramatically upon differentiation into adipocytes. Furthermore, inhibition of Cx43 degradation or constitutive overexpression of Cx43 blocks adipocyte differentiation. In the first events of adipogenesis, the connexin is highly phosphorylated, which is likely associated with enhanced Gap Junction (GJ) communication. In an intermediate state of adipocyte differentiation, Cx43 phosphorylation decreases, as it is displaced from the membrane and degraded through the proteasome; thus, Cx43 total protein is reduced. Cx is involved in cardiac disease as well as in obesity-related cardiovascular diseases. Different studies suggest that obesity together with a high-fat diet are related to the production of remodeling factors associated with expression and distribution of Cx43 in the atrium.

The rapid increase in industrialization and human population is leading to critical levels of environmental pollutants, such as agrochemicals or heavy metals, which affect the preservation and integrity of ecosystems, the accessibility to drinking water sources, and the quality of the air. As such, remediation of these issues demands strategies for implementing and designing novel technologies. In that regard, nanomaterials have unique physicochemical properties that make them desirable candidates for the detection and remediation of environmental pollutants. The scope of this review is to provide an analysis of the available nanomaterials that are being used as an approach to detect and remediate hazardous residues, comprising systems such as noble metals, biosensors, cyclodextrin-based polymers, and graphene oxide nanocomposites, to name a few. Furthermore, this work discusses said nanomaterials in terms of their effectiveness, sustainability, and selectivity as a guideline for researchers wishing to indulge in this relevant study area.

Insectivorous bats play a crucial role in agroecosystems by providing invaluable pest control services. With the escalating impacts of climate change, a comprehensive understanding of the environmental factors influencing bat activity becomes imperative for their conservation in agricultural landscapes. This study investigates the influence of weather conditions, specifically air temperature and relative humidity, on the timing activity and the relative abundance of five insectivorous bat species in central Chile. Data from automatic bat detectors and climatological stations are utilized for analysis. Our results unveil species-specific behaviors, with Tadarida brasiliensis exhibiting early emergence and extended activity periods compared to other bat species. Histiotus montanus and Lasiurus villosissimus display delayed onsets on more humid evenings, whereas Lasiurus varius and T. brasiliensis initiate activity earlier on colder nights compared to warmer ones. Relative humidity emerges as a key factor influencing relative abundance for all species, with more minutes with bat passes detected on drier nights. These findings suggest that global warming may influence observed bat behaviors, potentially altering foraging patterns and activity levels of these bat species. Moreover, as climate change continues, understanding the long-term impact on bat populations and their adaptive strategies is crucial for effective conservation measures. Further studies exploring these dynamics can provide valuable insights for shaping conservation efforts in the face of evolving environmental challenges.