The predictive value of various indicators of sperm for male fertility

Introduction. DNA fragmentation of sperm is one of the possible causes of reduced fertility potential of men. However, a significant correlation between conventional semen parameters and sperm DNA fragmentation was not found. This fact determines the relevance of the study of the influence of various parameters of sperm on male fertility.Materials and methods. The study included 60 men, aged 26–36 years (median – 30 years) with idiopathic infertility and the level of DNA fragmentation of sperm is higher than 15 %. These men were treated with hyperbaric oxygen therapy, after 3 months in vitro fertilization performed partners of these men. DNA fragmentation of sperm cells was determined by TUNEL (upper limit of normal – 15 %). The level of reactive oxygen species (ROS) of the ejaculate were determined by chemiluminescence (upper limit of normal – 0.64 mV/s).Results. The frequency of pregnancy in vitro fertilization was following: 62.8 and 64.7 % (p > 0.05) for the total number sperm of spermatozoa < 38 × 106 /ejaculate and ≥ 39 × 106 /ejaculate, respectively; 63.3 and 63.6 % (p > 0.05) for mobility (a + b) of spermatozoa < 40 and ≥ 40 %, respectively; 58.3 and 64.6 % (p > 0.05) for normal forms of spermatozoa < 4 and ≥ 4 %, respectively; 67.3 and 20.0 % (p < 0.05) for the level of DNA fragmentation of sperm ≤ 15 and > 15 %, respectively; 64.9 and 33.3 % (p < 0.05) for the level of ROS in semen ≤ 0.64 and > 0.64 mV/s, respectively.Conclusion. The probability of pregnancy after in vitro fertilization significantly depends on the levels of sperm DNA fragmentation in the sperm and level of ROS in semen

New developments in RiPP discovery, enzymology and engineering

Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a large group of natural products. A community-driven review in 2013 described the emerging commonalities in the biosynthesis of RiPPs and the opportunities they offered for bioengineering and genome mining. Since then, the field has seen tremendous advances in understanding of the mechanisms by which nature assembles these compounds, in engineering their biosynthetic machinery for a wide range of applications, and in the discovery of entirely new RiPP families using bioinformatic tools developed specifically for this compound class. The First International Conference on RiPPs was held in 2019, and the meeting participants assembled the current review describing new developments since 2013. The review discusses the new classes of RiPPs that have been discovered, the advances in our understanding of the installation of both primary and secondary post-translational modifications, and the mechanisms by which the enzymes recognize the leader peptides in their substrates. In addition, genome mining tools used for RiPP discovery are discussed as well as various strategies for RiPP engineering. An outlook section presents directions for future research