Characteristics of an Aeromonas trota strain isolated from cerebrospinal fluid.

Aeromonas are ubiquitous in aquatic habitats. However some species can cause infections in humans, but rarely meningitis. Here we describe the isolation and characterization of an Aeromonas strain from cerebrospinal fluid of a meningitis patient. The isolate, identified as A. trota by biochemical and molecular methods, was susceptible to ampicillin but resistant to cephalothin and cefazolin. Genome sequencing revealed virulence factor genes such as type VI secretion system, aerolysin and lateral flagella. The isolate exhibited swarming motility, hemolytic activity and adhesion and cytotoxicity on HeLa cells. This is the first report of A. trota associated with meningitis and its virulence characteristics.

Biochemical characteristics, adhesion, and cytotoxicity of environmental and clinical isolates of Herbaspirillum spp.

Herbaspirillum bacteria are best known as plant growth-promoting rhizobacteria but have also been recovered from clinical samples. Here, biochemical tests, matrix-assisted laser deionization-time of flight (MALDI-TOF) mass spectrometry, adherence, and cytotoxicity to eukaryotic cells were used to compare clinical and environmental isolates of Herbaspirillum spp. Discrete biochemical differences were observed between human and environmental strains. All strains adhered to HeLa cells at low densities, and cytotoxic effects were discrete, supporting the view that Herbaspirillum bacteria are opportunists with low virulence potential.

Chemically crosslinked guar gum hydrogels: An investigation on the water transport and its relationship with hydrocortisone release.

In this work, we describe the synthesis, the characterization, and the potential application of a pH-responsive guar gum-based hydrogel. The polysaccharide produced permanent hydrogels with improved biocompatibility. In this work, we report the chemical modification of guar gum (with glycidyl methacrylate) and its use, as the main constituent, in obtaining chemically cross-linked hydrogels. The morphology, swelling properties, and cytotoxicity of the resulting materials were studied in-depth. The hydrogels showed to be pH-responsive, and non-toxic being safe to use it as a biomaterial. In addition, we tested the potential of this one as a drug carrier. Herein, we have chosen hydrocortisone (HCS) as a drug model. The mechanism of HCS release changed as a function of pH, owing to different responses in each medium. Our results indicate that the guar gum hydrogels have great potential to be used, with safety, as a drug carrier.

Identification of a direct hemolytic effect dependent on the catalytic activity induced by phospholipase-D (dermonecrotic toxin) from brown spider venom.

Brown spiders have world-wide distribution and are the cause of health problems known as loxoscelism. Necrotic cutaneous lesions surrounding the bites and less intense systemic signs like renal failure, DIC, and hemolysis were observed. We studied molecular mechanism by which recombinant toxin, biochemically characterized as phospholipase-D, causes direct hemolysis (complement independent). Human erythrocytes treated with toxin showed direct hemolysis in a dose-dependent and time-dependent manner, as well as morphological changes in cell size and shape. Erythrocytes from human, rabbit, and sheep were more susceptible than those from horse. Hemolysis was not dependent on ABO group or Rhesus system. Confocal and FACS analyses using antibodies or GFP-phospholipase-D protein showed direct toxin binding to erythrocytes membrane. Moreover, toxin-treated erythrocytes reacted with annexin-V and showed alterations in their lipid raft profile. Divalent ion chelators significantly inhibited hemolysis evoked by phospholipase-D, which has magnesium at the catalytic domain. Chelators were more effective than PMSF (serine-protease inhibitor) that had no effect on hemolysis. By site-directed mutation at catalytic domain (histidine 12 by alanine), hemolysis and morphologic changes of erythrocytes (but not the toxin's ability of membrane binding) were inhibited, supporting that catalytic activity is involved in hemolysis and cellular alterations but not toxin cell binding. The results provide evidence that L. intermedia venom phospholipase-D triggers direct human blood cell hemolysis in a catalytic-dependent manner.

Pharmacokinetics and cytotoxic study of euphol from Euphorbia umbellata (Bruyns) Pax latex.

BACKGROUND: Medicinal plants are an important source to identify new active pharmaceutical compounds. Traditionally, the sap of Euphorbia umbellata is widely used to treat cancer and inflammatory conditions. These effects have been attributed to the presence of terpenes and phenolic compounds in the extracts of this plant. Euphol, a tetracyclic triterpene alcohol, is one of the major compounds present in Euphorbia species, and some biological activities have been attributed to this compound. PURPOSE: This study aimed to evaluate the in vitro cytotoxicity of euphol against Jurkat, HL-60, K-562, B16F10, and HRT-18 cells lines, as well as the biological stability, distribution, metabolism properties in vitro, and the determination of the concentration of euphol in the plasma and liver of rats. METHODS: The MTT reduction assay was used to evaluate the cytotoxicity of euphol against cancer cell lines, and the selectivity index, the morphology and cell cycle assays to evaluate the death mechanisms in K-562 and B16F10 lineages. UHPLC-MS was applied for the in vivo evaluation of the concentration of euphol in plasma and liver, and in vitro metabolic stability in human liver microsomes and S9 fraction, plasma protein binding, and stability in simulated gastric and intestinal fluids assays. CONCLUSIONS: This study demonstrated that euphol exhibited cytotoxic effects against a variety of cancer cells lines, selectivity against leukemia and possibly, the mechanism involved is apoptosis. The evaluation of stability, distribution, and metabolism properties showed that euphol was unstable in gastric and intestinal fluids, presenting moderate plasma protein binding with two hours elimination half-life and possible phase II liver metabolism. All the results suggested that further studies could be developed to prove the viability of euphol as an anticancer agent.

Enhanced gastric tolerability and improved anti-obesity effect of capsaicinoids-loaded PCL microparticles.

Capsaicinoids show several pharmacological effects including weight loss. However, their pungency limits the long-term use through the gastrointestinal tract. In that sense, the goal of this study was to prepare capsaicinoids-loaded poly(ε-caprolactone) microparticles as an oral carrier in order to improve their gastric tolerability and to make feasible the long-term treatment of obesity. Formulations containing 3, 5 and 10% capsaicinoids were successfully obtained by simple emulsion/solvent evaporation method. Values of encapsulation efficiency above 90% were achieved. Microparticles showed spherical shape and smooth surface. The particle size was suitable for oral use in order to provide an extended release through the gastrointestinal tract. No chemical bond was observed between drug and polymer. Microencapsulation led to drug amorphization. Formulations prolonged the release of capsaicinoids without changing the release kinetic (biexponential model). Microencapsulation increased the gastric tolerability of capsaicinoids because it prevented inflammatory processes in the stomach of rats. Microparticles containing 5% capsaicinoids demonstrated a statistically significant reduction of Lee index, mesenteric and retroperitoneal fat pads of rats with obesity induced by hypothalamic lesion using monosodium l-glutamate. In summary, capsaicinoids-loaded poly(ε-caprolactone) microparticles are low-irritative oral controlled-release carriers for a long-term use in obesity.

Standardized extract of Dicksonia sellowiana Presl. Hook (Dicksoniaceae) decreases oxidative damage in cultured endothelial cells and in rats.

AIMS: Aging and a variety of pathologies, including cancer, diabetes, cardiovascular and inflammatory diseases have been associated with reactive oxygen species (ROS), such as superoxide anion (O2·â»), hydroxyl radical (·OH) and hydrogen peroxide (H2O2) generation. Plant polyphenols bear radical scavenging/antioxidant activity. A phytomedicinal preparation obtained from aerial parts of Dicksonia sellowiana (Dicksoniaceae), a native plant from Central and South America, has been widely used in Brazil against asthma and presents beneficial effects in several other diseases, including cardiovascular disturbance. In this work, we investigated whether Dicksonia sellowiana, which is also known to contain high levels of polyphenols, presents antioxidant activity. METHODS: The antioxidant activity of the hydroalcoholic extract obtained from Dicksonia sellowiana leaves (HEDS) was investigated by in vitro and in vivo tests. RESULTS: HEDS (0.1-100 µg/mL) exhibited a strong scavenging activity against all reactive species tested (DPPH, O2·â»,·OH and H2O2; IC50=6.83±2.05, 11.6±5.4, 2.03±0.4, and 4.8±0.4 µg/mL, respectively). HEDS strongly protected endothelial cells against H2O2-induced oxidative stress by mechanisms other than increasing catalase activity. In addition, HEDS protected cell membrane from oxidative damage. HEDS, (20 and 40 mg/kg) inhibited lipid peroxidation in vivo (29.8% and 24.5%, respectively). CONCLUSIONS: According to our results, we can speculate that the traditional uses of Dicksonia sellowiana for cardiovascular diseases, asthma and skin diseases could be, at least in part, related to the potent antioxidant and endothelial protective activities of the plant.

Cytotoxicity of latex and pharmacobotanical study of leaves and stem of Euphorbia umbellata (Janaúba)

AbstractIn southern Brazil, the bottled latex of Synadenium grantii Hook f., Euphorbiaceae, is popularly used as a treatment of all types of cancer. Similarly, Synadenium umbellatum Pax. is used in the central western region of Brazil for the same purpose and in the same manner of use. Both plants are popularly known as janaúba or leitosinha. The objectives of this study were to use pharmacobotanical analysis to verify whether these two species, which are considered to be distinct, are actually the same to determine anatomical markers; to assist in the identification and differentiation of other Euphorbia; and to evaluate the cytotoxic activity of the latex in relation to HeLa and HRT-18 cells. Leaves and stems of the species were collected in Goiânia and Ponta Grossa and were investigated using scanning electron microscopy and optical microscopy techniques. The latex was also collected and analyzed in relation to its cytotoxic effect by employing MTT and NR techniques. The pharmacobotanical study of the specimens in both localities showed that they were the same species, namely Euphorbia umbellata (Pax) Bruyns, which is the scientific nomenclature accepted and confirmed by an expert taxonomist who specializes in Euphorbia. The pharmacobotanical characteristics highlighted in this study can assist in the identification of the taxon and contribute to the control of the quality of this plant drug. The evaluation of the latex in relation to HRT-18 cells demonstrated action after 48 h of experiment. In contrast, in relation to HeLa cells its induced cytotoxicity in all times and a dose-dependent manner. The IC50 values (72 h) observed were 252.58 ± 18.51 µg/ml and 263.42 ± 15.92 µg/ml to MTT experiment and 250.18 ± 19.48 µg/ml and 430.56 ± 19.71 µg/ml to NR experiment for the HeLa and HRT-18 cells, respectively.

Characterization of a specific interaction between ADAM23 and cellular prion protein.

ADAMs are transmembrane proteins implicated in several biological functions, including cytokine and growth factor shedding, fertilization, muscle and nervous system development. Here, we show for the first time that ADAM23, which is predominantly expressed in the central nervous system, co-localizes with cellular prion protein (PrP(C)) at plasma membrane of mouse hippocampal neurons and neuroblastoma cells. Co-immunoprecipitation and pull-down assay showed a physical interaction between ADAM23 and both recombinant and endogenous PrP(C). Glycosylation seems to be not relevant to the observed interaction since both ADAM23 and PrP(C) recombinant proteins expressed in bacteria or extracted from eukaryotic cells treated with tunicamycin are still able to bind each other. In vitro binding assays also suggested that the disintegrin domain of ADAM23 is able to interact directly with PrP(C). Taken together, these findings point out PrP(C) as a novel molecular partner for ADAM23 in the nervous systems.