Novel antimicrobial agents' discovery among the steroid derivatives.

Fourteen steroid compounds were in silico evaluated using computer program PASS as antimicrobial agents. The experimental studies evaluation revealed that all compounds have good antibacterial activity with MIC at range of 0.003-0.96 mg/mL and MBC 0.06-1.92 mg/mL. Almost all compounds except of compound 4 (3β-acetoxy-1/-p-chlorophenyl-3/-methyl-5α-androstano[17,16-d]pyrazoline) were more potent than Ampicillin, and they were equipotent or more potent than Streptomycine. All compounds exhibited good antifungal activity with MIC at 0.003-0.96 mg/mL and MFC at 0.006-1.92 mg/mL but with different sensitivity against fungi tested. According to docking studies 14-alpha demethylase inhibition may be responsible for antifungal activity. Prediction of toxicity by PROTOX and GUSAR revealed that compounds have low toxicity and can be considered as potential lead compounds for the further studies

Biomechanics of insect cuticle: an interdisciplinary experimental challenge

The cuticle exoskeleton plays a key role in facilitating the evolutionary success of insects. Since the mid of the last century, many different biomechanical properties of exoskeletons have been investigated, always utilizing the most sophisticated scientific methods available at the time. So far, information on the biomechanical properties of cuticle seems to be as diverse as the methods used to measure them. As a consequence, insect cuticle is often considered to exhibit the most complex and diverse biomechanical properties of any biological material. However, it remains unclear which role the respective measurement methods and sample treatments used in previous studies play in supporting this claim. This review provides a broad overview of examination techniques used to study biomechanical properties of insect exoskeletons and discusses their respective advantages and disadvantages in describing the properties of a complex material such as cuticle. Our meta-analysis of the present data confirms significant effects of the respective measurement methods, sample treatments and body parts on the obtained mechanical properties. Based on our findings, we highlight research gaps and point out important factors which should be taken into account in future studies on insect cuticle.19127