Time course of the effects of lipopolysaccharide on prepulse inhibition and brain nitrite content in mice

AbstractThe systemic administration of lipopolysaccharide (LPS) induces time-dependent behavioral alterations, which are related to sickness behavior and depression. The time-course effects of LPS on prepulse inhibition (PPI) remain unknown. Furthermore, the time-dependent effects of LPS on central nitrite content had not been investigated. Therefore, we studied alterations induced by single LPS (0.5mg/kg, i.p.) administration to mice on parameters, such as PPI, depressive- and anxiety-like behaviors, working memory, locomotor activity and motor coordination, 1.5 and 24h post-LPS administration. IL-1β and TNFα in the blood and brain as well as brain nitrite levels were evaluated in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST). An overall hypolocomotion was observed 1.5h post-LPS, along with depressive-like behaviors and deficits in working memory. Increments in IL-1β content in plasma and PFC, TNFα in plasma and decreases in nitrite levels in the ST and PFC were also verified. Twenty-four hours post-LPS treatment, depressive-like behaviors and working memory deficits persisted, while PPI levels significantly reduced along with increases in IL-1β content in the PFC and a decrease in nitrite levels in the HC, ST and PFC. Our data demonstrate that a delayed increase (i.e., 24h post-LPS) in PPI levels ensue, which may be useful behavioral parameter for LPS-induced depression. A decrease in nitrergic neurotransmission was associated with these behavioral findings

Susceptibility to amphotericin B of Candida spp. strains isolated in Ceará, Northeastern Brazil

Introduction Amphotericin B (AMB) is an antifungal agent used extensively in clinical medicine, yet resistance remains low. This study aims to evaluate the susceptibility of Candida spp. against AMB. Methods For broth microdilution susceptibility testing, 77 strains of Candida spp. were selected (32 C. albicans, 33 C. tropicalis, and 12 C. parapsilosis). The strains were considered susceptible when they exhibited MIC≤1.0µg/ml. Results None of the strains showed an MIC greater than 0.25µg/ml. Conclusions Further works are necessary, with a higher number of strains, to assess the validity of the results used in this study

Chemical Composition and Antifungal In Vitro and In Silico, Antioxidant, and Anticholinesterase Activities of Extracts and Constituents of Ouratea fieldingiana (DC.) Baill

Ouratea fieldingiana (Gardner) Engl is popularly used for wound healing. This study describes the main chemical compounds present in extracts of O. fieldingiana and evaluates their biological potential by investigating antifungal, antioxidant, and anticholinesterase activities. The action mechanism of main antifungal compound was investigated by molecular docking using the enzyme sterol 14-α demethylase, CYP51, required for ergosterol biosynthesis. The seeds and leaves were extracted with ethanol in a Soxhlet apparatus and by maceration, respectively. Both extracts were subjected to silica gel column chromatography for isolation of main constituents, followed by purification in sephadex. The structures of compounds were established by 1H and 13C-NMR spectroscopy and identified by comparison with literature data as amentoflavone and kaempferol 3-O-rutinoside, respectively. The antioxidant activities of the extracts were determined by the DPPH and ABTS free radical inhibition methods. In general, the extracts with the highest antioxidant activity corresponded to those with higher content of phenolic compounds and flavonoids. The ethanol extracts and two isolated compounds presented relevant antifungal activity against several Candida strains. The in silico findings revealed that the compound amentoflavone coupled with the CYP450 protein due to the low energy stabilization (-9.39 kcal/mol), indicating a possible mechanism of action by inhibition of the ergosterol biosynthesis of Candida fungi