Francisca Inês de Sousa Freitas

Ultrastructural study on the morphological changes to male worms of Schistosoma mansoni after in vitro exposure to allicin

INTRODUCTION Garlic has a wide range of actions, including antibacterial, antiviral, antifungal, antiprotozoal and anthelmintic actions. This antiparasitic activity has been attributed to allicin, which is the main constituent of garlic. The present study aimed to investigate the in vitro activity of allicin on the tegument of adult Schistosoma mansoni worms using scanning electron microscopy. METHODS Swiss Webster mice were infected with S. mansoni cercariae (100 per mouse) and sacrificed 50 days later to acquire the adult worms. These worms were collected by perfusion and placed in RPMI medium 1,640 at 37°C before transferring to RPMI media containing 0 (control), 5, 10, 15 and 20mg/mL of allicin, where they were incubated for 2h. The worms were fixed in 2.5% glutaraldehyde solution, washed twice, post-fixed in osmium tetroxide, washed twice and then dehydrated with ascending grades of ethanol. The samples were air-dried, mounted on stubs, gold coated in an ion sputtering unit and viewed using a scanning electron microscope. RESULTS A concentration of 5mg/mL caused wrinkling in the tegument; a concentration of 10mg/mL resulted in changes to tubercles and loss or modification of spines. With 15 and 20mg/mL increasing damage to the tegument could be seen, such as vesicle formation and the presence of ulcers. CONCLUSIONS These findings demonstrate the effect of allicin on adult S. mansoni worms and indicate that most of the changes occur at concentrations greater than that normally indicated for treatment.

Lipolytic activity of Staphylococcus aureus from human wounds, animals, foods, and food-contact surfaces in Brazil.

INTRODUCTION S. aureus is of great importance to public health due to its pathogenicity. This study aimed to evaluate lipase production by S. aureus isolates from different sources. METHODOLOGY Lipolytic activity was determined using Tween-Calcium agar (48 hours; 35°C). RESULTS Eighty-six percent of the isolates from human wounds were positive for lipase production. The frequencies of isolates positive for lipase production were 33.3% from cow udders, 15.4% from the nasal cavities of cattle, 82.9% from ricotta cheeses, and 100% and 91.7% from meat- and vegetable-contact surfaces, respectively. CONCLUSION The production of lipase varied among the isolates according to their source.