New Insights into Cutaneous Asepsis: Synergism between Pfaffia and Rosemary Extracts.

(1) Background: In hospitals, medical and dental clinics, antiseptics or disinfectants play an essential role in the control of nosocomial infections. This study aimed to evaluate R. officinalis and P. paniculata glycolic extracts regarding: (I) their antimicrobial action on planktonic and biofilm (monotypic and cutaneous biofilm model-S. aureus, S. epidermidis and C. acnes); and (II) their cytotoxicity on human keratinocytes (HaCaT). (2) Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were performed (CLSI protocol M7-A6 and M11-A8). MTT analysis was used to evaluate the antibiofilm activity of the extracts on biofilms and their cytotoxicity on human keratinocytes. (3) Results: The combined glycolic extracts MIX A (75% P. paniculata + 25% R. officinalis); MIX B (50% P. paniculata + 50% R. officinalis); and MIX C (25% P. paniculata + 75% R. officinalis) promoted MBC values by 50 mg/mL on S. aureus, absent on S. epidermidis, and ranged 6.25-50 mg/mL for C. acnes. The cutaneous biofilm model was reduced more than 90%. In addition, it showed biocompatibility with human keratinocytes, resulting in percentages of viability greater than 50%. (4) Conclusions: The combination of extracts promoted antimicrobial action on planktonic cultures, and monotypic and heterotypic biofilms of skin pathogens. Additionally, these extracts are biocompatible against human keratinocytes.

Autophagy in Paracoccidioides brasiliensis under normal mycelia to yeast transition and under selective nutrient deprivation.

Paracoccidioides spp. is a thermally dimorphic fungus endemic to Latin America and the etiological agent of paracoccidioidomycosis (PCM), a granulomatous disease acquired through fungal propagule inhalation by its mammalian host. The infection is established after successful mycelia to yeast transition in the host pulmonary alveoli. The challenging environment inside the host exposes the fungus to the need of adaptation in order to circumvent nutritional, thermal, oxidative, immunological and other stresses that can directly affect their survival. Considering that autophagy is a response to abrupt environmental changes and is induced by stress conditions, this study hypothesizes that this process might be crucially involved in the adaptation of Paracoccidioides spp. to the host and, therefore, it is essential for the proper establishment of the disease. By labelling autophagous vesicles with monodansylcadaverine, autophagy was observed as an early event in cells during the normal mycelium to yeast transition, as well as in yeast cells of P. brasiliensis under glucose deprivation, and under either rapamycin or 3-methyladenine (3-MA). Findings in this study demonstrated that autophagy is triggered in P. brasiliensis during the thermal-induced mycelium to yeast transition and by glucose-limited conditions in yeasts, both of which modulated by rapamycin or 3-MA. Certainly, further genetic and in vivo analyses are needed in order to finally address the contribution of autophagy for adaptation. Yet, our data propose that autophagy possibly plays an important role in Paracoccidioides brasiliensis virulence and pathogenicity.

Physiological evaluation of the behavior and epidermis of freshwater planarians (Girardia tigrina and Girardia sp.) exposed to stressors.

Planarians are metazoan freshwater flatworms which are free-living organisms. Their body has pluripotent stem cell promoters of tissue regeneration capacity. The water temperature and the potential of hydrogen (pH) of lentic ecosystems are important factors involved in the distribution and abundance of these animals. Although the pH factor is directly related to the physiology and behavior of planarians, their adaptive and regenerating capacities still remain unknown. The Critical Thermal Maximum (CTM) is a very widespread method used in the evaluation of thermal tolerance. In this study, Girardia tigrina (Girard, 1850) and Girardia sp., a species found in Brazil, which is under study as a new species, had their epidermis assessed by scanning electron microscopy (SEM) to analyze their physiological structures before and after exposure to different stressors. SEM was used as a method to evaluate the planarians' epidermis as a result of the increasing temperature (CTM) and pH alterations, the latter with the use of a new methodology defined as Critical Hydrogen ion concentration Maximum (CHM). In increasing temperatures from 20°C to 37°C, both Girardia tigrina and Girardia sp. proved to be adaptable to thermal stress. Girardia sp. was shown to be more resistant to higher temperatures. However, Girardia tigrina was more resistant to extreme pH conditions (4.0 to 10.0). SEM analysis showed morphological differences among planarian species, such as the arrangement of the structures and cell types of the dorsal epidermis. Moreover, planarians demonstrated the ability to change the surrounding pH of their external environment in order to maintain the function of their physiological mechanisms, suggesting that these animals have a complex survival system, possibly related to protonephridia, flame cells and excretory pores.This article has an associated First Person interview with the first author of the paper.