Antibiotic resistance is a global health concern. Strains of pathogenic microorganisms that have developed resistance to multiple antibiotics, such as {MRSA}, are extremely difficult to treat, and alternative methods for tackling pathogenic microorganisms are in demand. One potential target for new therapeutics is inhibition of quorum sensing: how microorganisms communicate and form biofilms in a density-dependent manner. Inhibiting this system via ‘quorum quenching’ ({QQ}) is a promising route to new pharmaceuticals and for controlling biofilm formation and growth. Quorum sensing also provides interesting possibilities in synthetic biology for producing novel products, biosensors, bioactive molecules, and so on. This book covers the biology of quorum sensing and quenching, and potential sources of {QQ} enzymes and other inhibitors, as well as an overview of their mechanism and potential biotech applications. The book also covers the potential for new drug development from {QQ}, covering a range of related topics including protein engineering, imaging and computational studies, and integrated systems. This book is an ideal companion to researchers in chemical biology and medicinal chemistry, particularly those interested in biofilm formation, quorum sensing, novel antimicrobial development, synthetic biology and enzymology.

BACKGROUND: Methotrexate (MTX) is an antineoplastic/immunosuppressive drug, whose clinical use is impeded owing to its serious adverse effects; one of which is acute kidney injury (AKI). Most of MTX complications emerged from the provoked pro-oxidant-, pro-inflammatory- and pro-apoptotic effects. Quillaja saponaria bark saponin (QBS) is a bioactive triterpene that has been traditionally used as an antitussive, anti-inflammatory supplement, and to boost the immune system due to its potent antioxidant- and anti-inflammatory activities. However, the protective/therapeutic potential of QBS against AKI has not been previously evaluated. This study aimed to assess the modulatory effect of QBS on MTX-induced reno-toxicity.

METHODS: Thirty-two male rats were divided into 4-groups. Control rats received oral saline (group-I). In group-II, rats administered QBS orally for 10-days. In group-III, rats were injected with single i.p. MTX (20 mg/kg) on day-5. Rats in group-IV received QBS and MTX. Serum BUN/creatinine levels were measured, as kidney-damage-indicating biomarkers. Renal malondialdehyde (MDA), reduced-glutathione (GSH) and nitric-oxide (NO) were determined, as oxidative-stress indices. Renal expression of TNF-α protein and Nrf-2/Keap-1 mRNAs were evaluated as regulators of inflammation. Renal Bcl-2/cleaved caspase-3 immunoreactivities were evaluated as apoptosis indicators.

RESULTS: Exaggerated kidney injury upon MTX treatment was evidenced histologically and biochemically. QBS attenuated MTX-mediated renal degeneration, oxidant-burden enhancement, excessive inflammation, and proapoptotic induction. Histopathological analysis further confirmed the reno-protective microenvironment rendered by QBS.

CONCLUSIONS: In conclusion, our results suggest the prophylactic and/or therapeutic effects of QBS in treating MTX-induced AKI. Such reno-protection is most-likely mediated via Nrf-2 induction that interferes with oxidant load, inflammatory pathways, and proapoptotic signaling.

Virginity is the nullity of sexual experience in females. However, the use of virginity testing as proof of previous involvement in sexual relations is dependent on having an intact hymen, which refers to a hymen with no signs of previous penetrating injury. Although the quality of this evidence in questioned virginity is extremely poor and considered a violation of human rights, it still constitutes a major facet in medicolegal investigations of sexual assaults. This work evaluates virginity testing as currently practiced in many countries, including Egypt, in terms of medical and legal considerations.