Medicinal and aromatic plants are known to have a wide range of uses and health benefits, and should be exploited for their bioactivity. Here we evaluated the antimicrobial activity of decoctions of Satureja montana L. and Origanum majorana L. against Gram-positive and Gram-negative bacteria and Candida spp. as well as their mechanism of action and phenolic characterization. The Satureja montana and Origanum majorana extracts were effective against a broad set of species, including the Gram-positive Staphylococcus aureus, Enterococcus faecalis, and Streptococcus dysgalactiae and the Gram-negative Klebsiella pneumoniae and Pseudomonas aeruginosa. Both extracts were found to have rosmarinic acid as the main phenolic compound and to exert their antimicrobial activity at the level of the cell membrane. Membrane perturbations by the extracts impaired cell membrane integrity only a few hours after exposure. This study confirms the bioactive potential of Satureja montana and Origanum majorana decoctions, and supports the development of novel formulations with wide antimicrobial properties based on these medicinal and aromatic herbs.

Bacterial Vaginosis (BV) involves the presence of a multi-species biofilm adhered to vaginal epithelial cells, but its in-depth study has been limited due to the complexity of the bacterial community, which makes the design of in vitro models challenging. Perhaps the most common experimental technique to quantify biofilms is the crystal violet (CV) staining method. Despite its widespread utilization, the CV method is not without flaws. While biofilm CV quantification within the same strain in different conditions is normally accepted, assessing multi-species biofilms formation by CV staining might provide significant bias. For BV research, determining possible synergism or antagonism between species is a fundamental step for assessing the roles of individual species in BV development. Herein, we provide our perspective on how CV fails to properly quantify an in vitro triple-species biofilm composed of Gardnerella vaginalis, Fannyhessea (Atopobium) vaginae, and Prevotella bivia, three common BV-associated bacteria thought to play key roles in incident BV pathogenesis. We compared the CV method with total colony forming units (CFU) and fluorescence microscopy cell count methods. Not surprisingly, when comparing single-species biofilms, the relationship between biofilm biomass, total number of cells, and total cultivable cells was very different between each tested method, and also varied with the time of incubation. Thus, despite its wide utilization for single-species biofilm quantification, the CV method should not be considered for accurate quantification of multi-species biofilms in BV pathogenesis research.

No abstract

It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.

Antibiotic activity in serum from a model for type II diabetes was similar to that in normal sera or media containing cholesterol but lacking glucose, insulin, or both. The ratio of effects of broth plus obese-rat serum to effects of broth plus lean-rat serum supplemented with cholesterol approached or equaled 1.The interactions of antibiotics with serum components, including serum proteins and cholesterol, have been demonstrated to be important determinants of their activity in serum. It has been well documented that the levels and types of proteins found in serum can profoundly affect antibiotic activity, especially that of penicillin and others of the 1-lactam class (1,2). Another serum component, cholesterol, which is commonly elevated in persons in Western society, can act as a competitive inhibitor for members of the polyene class of antibiotics, such as amphotericin B (6, 11). Obesity is often associated with changes in the levels of serum components. In obesity-associated type II diabetes, both serum insulin and glucose can be elevated. Altered levels of cholesterol, triglycerides, free fatty acids, and lipoproteins are also commonly associated with obesity and type II diabetes (3,10,13,14). The effect that these skewed levels of serum components have on antibiotic activity is not known.In this study, we

No abstract

No abstract

No abstract