Biosynthesis of selenium nanoparticles using Klebsiella pneumoniae and their recovery by a simple sterilization process

The use of biologically derived metal nanoparticles for various proposes is going to be an issue of considerable importance; thus, appropriate methods should be developed and tested for the biological synthesis and recovery of these nanoparticles from bacterial cells. In this research study, a strain of Klebsiella pneumoniae was tested for its ability to synthesize elemental selenium nanoparticles from selenium chloride. A broth of Klebsiella pneumoniae culture containing selenium nanoparticles was subjected to sterilization at 121ºC and 17 psi for 20 minutes. Released selenium nanoparticles ranged in size from 100 to 550 nm, with an average size of 245 nm. Our study also showed that no chemical changes occurred in selenium nanoparticles during the wet heat sterilization process. Therefore, the wet heat sterilization process can be used successfully to recover elemental selenium from bacterial cells.

Acute and subchronic oral toxicity of Galega officinalis in rats.

Galega officinalis L. (Papilionaceae) is widely used in folk medicine as antidiabetic or for increasing lactation. There is a little information about its possible toxicity. In this study, acute and subchronic toxicity of aerial parts of Galega officinalis in Wistar rats have been evaluated. For the acute toxicity study, the animals received orally four different single dose of plant suspension and were kept under observation for 14 days. The results indicated that LD50 of Galega officinalis is higher than 5 g/kg. In the subchronic study, 48 rats were divided into four groups and were fed a diet containing 0%, 0.15%, 1.5% and 3% (w/w) of Galega officinalis. After 90 days blood and tissue samples were taken for hematological, biochemical and histopathological determinations. An increase in serum levels of cholesterol, creatine phosphokinase, lactate dehydrogenase and total and conjugated bilirubin was observed. Some parameters such as calcium, albumin, albumin/globulin ratio, hematocrit, WBC and platelet counts were decreased. In microscopic examination, sinusoidal congestion in liver and alveolar hemorrhage was observed. Other parameters showed non-significant difference between treatment and control groups. Present data suggest that liver and lung could serve as target organs in oral toxicity of this plant.