Early Effects of Rhodomyrtone on Membrane Integrity in Methicillin-Resistant Staphylococcus aureus.

Strong evidence of high potency of rhodomyrtone as a promising antibacterial agent against pathogenic gram-positive bacteria has been clearly demonstrated in our previous work. The aim of this study was to provide insight into early action of rhodomyrtone, an acylphloroglucinol, on membrane damage in multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA). Early effects of rhodomyrtone on the bacterial membrane integrity were detected in a time-course study. Flow cytometry revealed a reduction in green fluorescent emission and increase in uptake of propidium iodide in rhodomyrtone-treated bacterial cells in a concentration- and time-dependent manner. Disruption of cytoplasmic membrane was further monitored by measuring cellular adenosine triphosphate (ATP) and potassium ion (K+). Leakage of both ATP and K+ and significant decrease in intracellular ATP in MRSA were observed following treatment. Pronounced changes in the bacterial ultrastructure and morphology were confirmed by transmission electron microscopy and scanning electron microscopy. Bacterial cell disruption, holes in cell surface, and bulge formations were noted in rhodomyrtone-treated cells. In this study, we provided relevant data to clarify that rhodomyrtone is a bacterial cell membrane-damaging agent. A possible early effect of this novel compound involves bacterial membrane disruption.

Component-resolved diagnostics in Thai children with cow's milk and egg allergy.

BACKGROUND AND OBJECTIVE: Component-resolved diagnostics (CRD) have garnered a lot of attention in recent years in the diagnosis of food allergies. We aimed to investigate sensitization against cow's milk and egg white components, and to study the clinical usefulness of serum food-specific immunoglobulin E (sIgE) to cow's milk and egg white components in Thai children with cow's milk and egg allergies. METHOD: Children with IgE-mediated cow's milk and/or egg allergy were enrolled. Clinical reactions were determined. Specific IgE against cow's milk, egg white, alpha-lactalbumin (ALA), beta-lactoglobulin (BLG), casein, ovomucoid, ovalbumin and conalbumin were measured. RESULTS: Thirteen cow's milk allergic subjects and 32 egg allergic subjects were identified. The sensitization rate to BLG and casein was 91.7%, followed by ALA (66.7%) for cow's milk, and the sensitization rate to ovalbumin was 93.8%, followed by ovomucoid (81.3%) and conalbumin (37.5%) for egg. Patients in the urticaria group had a higher level of casein sIgE than the atopic dermatitis (AD) group but this difference was not significant (9.8 kUA/L vs. 0.9 kUA/L, p = 0.11). The level of ovomucoid sIgE was significantly higher in the non-AD group than in the AD group (3.8 kUA/L vs. 1.3 kUA/L, p = 0.048). CONCLUSIONS: BLG and casein for cow's milk and ovomucoid and ovalbumin for egg were the common components causing sensitization in cow's milk and egg allergic patients. Among the patients with cow's milk allergy, the level of casein sIgE in the urticaria group tended to be higher than the AD group, and in egg allergic patients, the non-AD group had a significantly higher ovomucoid sIgE level compared with the AD group.

Mechanisms of 1-hydroxy-2-hydroxymethylanthraquinone from Coptosapelta flavescens as an anti-giardial activity.

Thai medicinal plants represent a rich source of potential anti-parasitic compounds. 1-hydroxy-2-hydroxymethylanthraquinone (CFQ) purified from Coptosapelta flavescens, a plant commonly used to expel intestinal worms, indicated potential anti-giardial agent as shown in a previous study. This study aims to investigate its mechanism of action. We assessed whether CFQ was involved as an inducer of apoptosis as well as having effects on the fine structure of Giardia intestinalis trophozoites. We observed the consequences of exposing G. intestinalis trophozoites to CFQ and metronidazole, both had an IC50 of 0.42µg/ml, after 6, 12 and 24h exposure. An apoptosis in trophozoite was confirmed by the AnnexinV-FITC assay and as viewed by flow cytometry. CFQ at its IC50 induced apoptosis as early as 6h after incubation while metronidazole produced little or no apoptosis at its IC50 value. Ultrastructural analyzes at 24h demonstrated that both CFQ and metronidazole induced several physical alterations, including the appearance of wrinkled and rounded cells, membrane blebbing, ventral disc damage, electron dense precipitates in the nuclei, all of which were indicative of cell death. However, membrane rupture was found only in G. intestinalis exposed to CFQ and this proved the induction of apoptosis. Taken together, we have provided a mechanistic explanation of the action of CFQ against G. intestinalis trophozoites. These results have provided further evidence that CFQ is a new compound that has the potential for use to treat infections from G. intestinalis.