Standardized Heat Fixation for Blood Smears

Because a technique was needed for good fixation of blood smears without the use of solvents such as methanol, the effect of heat fixation on human and rat blood smears was studied. Slides were placed in a fused silica dish, covered by a Pyrex petri dish lid, and heated for 5 min in an oven at 150° C. After such fixation, smears stained by Giemsa' s solution showed that the blood elements retained their characteristic morphology. Thus, even though volatile substances may be lost and heat-labile constituents may be modified, this simple method avoids contact of the cells with solvents.     

Production of metabolites with antioxidant activity by Botryosphaeria dothidea in submerged fermentation

Bioprocess and Biosystems Engineering - Antioxidants are able of inhibiting free radicals and play an important role in human diet, protection of foods, anti-aging cosmetics, among others. Fungi...     

A new record of whale shark Rhincodon typus in Brazilian waters: a report of association with Caranx crysos

In May 2011, a Rhincodon typus was sighted on the continental shelf of the central Brazilian coast, in the vicinity of a gas platform. During the video record, an interspecific following association was observed between a Caranx crysos school and the R. typus.     

Polyhydroxyfullerene Binds Cadmium Ions and Alleviates Metal-Induced Oxidative Stress in Saccharomyces cerevisiae

The water-soluble polyhydroxyfullerene (PHF) is a functionalized carbon nanomaterial with several industrial and commercial applications. There have been controversial reports on the toxicity and/or antioxidant properties of fullerenes and their derivatives. Conversely, metals have been recognized as toxic mainly due to their ability to induce oxidative stress in living organisms. We investigated the interactive effects of PHF and cadmium ions (Cd) on the model yeast Saccharomyces cerevisiae by exposing cells to Cd (≤5 mg liter⁻¹) in the absence or presence of PHF (≤500 mg liter⁻¹) at different pHs (5.8 to 6.8). In the absence of Cd, PHF stimulated yeast growth up to 10.4%. Cd inhibited growth up to 79.7%, induced intracellular accumulation of reactive oxygen species (ROS), and promoted plasma membrane disruption in a dose- and pH-dependent manner. The negative effects of Cd on growth were attenuated by the presence of PHF, and maximum growth recovery (53.8%) was obtained at the highest PHF concentration and pH. The coexposure to Cd and PHF decreased ROS accumulation up to 36.7% and membrane disruption up to 30.7% in a dose- and pH-dependent manner. Two mechanisms helped to explain the role of PHF in alleviating Cd toxicity to yeasts: PHF decreased Cd-induced oxidative stress and bound significant amounts of Cd in the extracellular medium, reducing its bioavailability to the cells.