Streptococcus pneumoniae uses glutathione to defend against oxidative stress and metal ion toxicity

The thiol-containing tripeptide glutathione is an important cellular constituent of many eukaryotic and prokaryotic cells. In addition to its disulfide reductase activity, glutathione is known to protect cells from many forms of physiological stress. This report represents the first investigation into the role of glutathione in the Gram-positive pathogen Streptococcus pneumoniae. We demonstrate that pneumococci import extracellular glutathione using the ABC transporter substrate binding protein GshT. Mutation of gshT and the gene encoding glutathione reductase (gor) increases pneumococcal sensitivity to the superoxide generating compound paraquat, illustrating the importance of glutathione utilization in pneumococcal oxidative stress resistance. In addition, the gshT and gor mutant strains are hypersensitive to challenge with the divalent metal ions copper, cadmium, and zinc. The importance of glutathione utilization in pneumococcal colonization and invasion of the host is demonstrated by the attenuated phenotype of the gshT mutant strain in a mouse model of infection.Adam J. Potter, Claudia Trappetti, and James C. Pato

Bioactives in legumes

Legumes exert several health benefits: anticancer, anti-inflammatory, anti-obesity, antioxidant, antimicrobial and heart protection. Bioactive compounds, namely phenolics, peptides, saponins, vitamins and lipids, are responsible for these properties. Legume wastewater was shown to contain moderate amounts of phenolics (0.3–0.6 mg/g), proteins (0.7–1.5 g/100 g) and saponins (6–14 mg/g). Phenolic compounds express all activities described above and include the following nutrients: phenolic acids, flavonoids, anthocyanins, flavanols, flavones, flavanones and tannins. Bioactive peptides consists of albumin, globulin and defensin, responsible for numerous properties. Saponins inhibit cancer growth and prevent obesity, while vitamins act as anti-inflammatory and antioxidants. Certain lipids may inhibit cancer growth and act as anti-inflammatory but were not detected in legume wastewater. Vitamin content of legume cooking water has not been investigated yet, offering noteworthy opportunities to researchers. Therefore, legume wastewater might express interesting bioactivities. Industrially, this by-product could be used to extract bioactives or as a wholesome source