Surfactants: physicochemical interactions with biological macromolecules

Macromolecules are essential cellular components in biological systems responsible for performing a large number of functions that are necessary for growth and perseverance of living organisms. Proteins, lipids and carbohydrates are three major classes of biological macromolecules. To predict the structure, function, and behaviour of any cluster of macromolecules, it is necessary to understand the interaction between them and other components through basic principles of chemistry and physics. An important number of macromolecules are present in mixtures with surfactants, where a combi- nation of hydrophobic and electrostatic interactions is responsible for the specific properties of any solution. It has been demonstrated that surfactants can help the formation of helices in some proteins thereby promot- ing protein structure formation. On the other hand, there is extensive research towards the use of surfac- tants to solubilize drugs and pharmaceuticals; there- fore, it is evident that the interaction between surfactants with macromolecules is important for many applications which includes environmental processes and the pharmaceutical industry. In this review, we describe the properties of different types of surfactants that are relevant for their physicochemical interactions with biological macromolecules, from macromolecules–surfactant complexes to hydrophobic and electrostatic interactions

Sophorolipid biosurfactants: Possible uses as antibacterial and antibiofilm agent.

Biosurfactants are amphipathic, surface-active molecules of microbial origin which accumulate at interfaces reducing interfacial tension and leading to the formation of aggregated micellular structures in solution. Some biosurfactants have been reported to have antimicrobial properties, the ability to prevent adhesion and to disrupt biofilm formation. We investigated antimicrobial properties and biofilm disruption using sophorolipids at different concentrations. Growth of Gram negative Cupriavidus necator ATCC 17699 and Gram positive Bacillus subtilis BBK006 were inhibited by sophorolipids at concentrations of 5% v/v with a bactericidal effect. Sophorolipids (5% v/v) were also able to disrupt biofilms formed by single and mixed cultures of B. subtilis BBK006 and Staphylococcus aureus ATCC 9144 under static and flow conditions, as was observed by scanning electron microscopy. The results indicated that sophorolipids may be promising compounds for use in biomedical application as adjuvants to other antimicrobial against some pathogens through inhibition of growth and/or biofilm disruption

Exomorfología y anatomía de órganos vegetativos aéreos en especies de Flourensia DC. (Asteraceae) con importancia fitoquímica

El género Flourensia DC. es americano y comprende 32 especies. Son arbustos resinosos utilizados en medicina popular; poseen un potencial valor económico, por lo que, en algunas especies representantes, se han caracterizado sus compuestos químicos y determinado algunos posibles usos. En el presente trabajo, se estudió la exomorfología y anatomía de órganos vegetativos de F. hirta S. F. Blake, F. leptopoda S. F. Blake, F. niederleinii S. F. Blake y F. tortuosa Griseb., especies endémicas del centro de Argentina. Se observó que todas son similares en cuanto a la anatomía de hoja y tallo. En cuanto al estudio de la epidermis foliar, se concluye que es posible diferenciar las especies teniendo en cuenta la frecuencia estomática y la presencia de tricomas. Finalmente, las diferencias más notables se encontraron en la exomorfología foliar ya que se observó una gran variación en cuanto a la forma de las hojas y tamaño de las láminas y pecíolos. Con respecto a las estructuras secretoras, se encontraron tricomas y conductos secretores esquizógenos en las hojas y los tallos de todas las especies, las cuales serían responsables de la producción y secreción de las resinas.The genus Flourensia DC. is American and comprises 32 species. They are resiniferous shrubs used in folk medicine. As they have potential economic value, its chemical compounds have been characterized and some possible uses identified. In this work, the exomorphology and anatomy of vegetative organs of F. hirta S. F. Blake, F. leptopoda S. F. Blake, F. niederleinii S. F. Blake and F. tortuosa Griseb., endemic species from central Argentina, have been studied. All species are similar in leaf and stem anatomy. Regarding the epidermis, it is possible to differentiate the species according to the stomatal frequency and the presence of trichomes. Finally, the most remarkable differences were found in leaf exomorphology, since there was a large variation in shape and size of blades and petioles. Concerning the secretory structures, trichomes and secretory ducts were found in the leaves and stems of all species, which would be responsible for the production and secretion of the resins

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Diffusive Release of Photosensitizing Agents (PS) from Novel PVA-Borate Semi-Solid Drug Carriers Through In Vitro Oral Streptococcus mutans Biofilm

Background: Streptococcus mutans, one of the agent of human dental caries, is particularly effective at forming biofilms on the hard tissues of the human oral cavity; the purpose of this study was to investigate and quantify the diffusional release of photosentising agents (PS): methylene blue (MB), toludine blue (TB), rose bengal (RB) and methyl orange (MO) from Polyvinyl alcohol (PVA)-borate semi-solid gels in the presence of in vitro oral Streptococcus mutans biofilm. Methods: S. mutans biofilm growths were ascertained to ensure proper dental plaque formation and were characterized using confocal microscopy. Release profiles for MB, TB, RB and MO-loaded PVA-borate semi-solids in the absence of biofilms were directly compared to their counterparts in the presence of S. mutans biofilms. In addition, their diffusion coefficients and resistances were determined. Results: The confocal imaging results showed that biofilms grown over a 5-day period had a generally uninterrupted film of colonies occupying the entire surface area of growth surface of a nylon mesh support with approximately 60 µm biofilm size. The overall diffusion resistance of all PVA-borate semi-solids in the presence of S. mutans biofilms was about 1.2 times lower than the diffusion resistance for PVAborate semi-solids in the absence of biofilms. The diffusion resistances for all studied PS, indicate that electrostatic forces and molecular size play an important part in controlled and sustained drug release from PVA-borate semi-solids. Conclusions: PVA-borate semi-solids as novel PSs carriers might offer an innovative delivery system in the treatment against Streptococcus mutans