Experimental research using spermatozoa, a highly specialized cell with organelles involved in gene transfer, energy supply and cellular motility, has always occupied the forefront of studies in cell and reproductive biology. Several spermatological experiments have focused on the attraction of a spermatozoon toward the egg – sperm chemotaxis or sperm guidance. This process ubiquitously occurs in the reproductive system of many organisms. After its discovery in the late 19th century in plants, sperm chemotaxis is known to play a crucial role in fertilization success in both plants and animals. Spermatology has expanded in focus in recent years, as the structure of molecules relevant to sperm chemotaxis has been recently determined in several species of invertebrates and vertebrates, which promises remarkable progress for understanding events relevant to sexual reproduction. Reflecting upon these trends in the long history of sperm chemotaxis, Flagellar Mechanics and Sperm Guidance gathers leaders in the field of spermatology, who have presented their experimental research on the chemical cues behind flagellate behavior in a variety of organisms including bikonts and spermatozoa of marine invertebrates and vertebrates (fish, amphibians and mammals). Reviews presented in this monograph provide both basic and detailed information on the initiation and activation of sperm motility at spawning, sperm thermotaxis, and other mechanics such as mathematical models of a spermatozoon swimming. A comparison between features of sperm chemotaxis among different organisms is also given. Flagellar Mechanics and Sperm Guidance will stir interest in spermatology research among a broad variety of readers including researchers, Ph.D. students studying reproductive biology and teachers involved in advanced biology courses.

Rhizobia are composed of specific groups of bacteria that have the ability to induce symbiotic nitrogen-fixing nodules on the roots or stems of leguminous plants. Rhizobia have attracted a great attention for more than 4 decades because of their enormous agricultural and economic value in sustainable agriculture. Up to the present time, many legumes have been found to be nodulated by several rhizobial species in diverse taxonomic groups. An assessment of rhizobial diversity provides pivotal information in understanding the horizontal gene transfer among bacterial genera and species, the bacterial evolution and the symbiotic effectiveness. The classification of rhizobia is becoming increasingly complex and is revised periodically because of new findings that propose new genera and new species. Phenotypic and Genotypic Diversity of Rhizobia presents the application of conventional and molecular analyses, including numerical analysis, enzyme patterns, serological studies, plasmid profile, polymerase chain reaction (PCR)-fingerprinting, amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP), PCR-RFLP and sequence-based methods, to the examination of rhizobial diversity. Principles of these techniques, the resolving power, the advantage and the limitation of these techniques are evaluated. Current taxonomy of rhizobia classifies them into 17 genera and 118 species. The book explains background knowledge about rhizobia and follows this up with a broad perspective on rhizobial diversity, information on characteristics specific to each group of rhizobia, the relationship among rhizobial groups as well as genetic factors contributed to rhizobial diversity. Contemporary methods for examination of rhizobial diversity are also suggested and discussed. Readers of this e-book will find updated information on key concepts in classification and taxonomy of rhizobia, the categories and techniques used to examine the phenotypic and genotypic diversity of rhizobia (including numerical analysis, enzyme patterns, serological study, plasmid profile, polymerase chain reaction (PCR)-fingerprinting, amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP), PCR-RFLP and sequence analysis).

In the book, The Origin of Life in Fire and Ice, the author proposes a simple and direct path which may have caused the formation of one of the earliest organisms described using observations found in scientific literature: the last universal common ancestor (LUCA). The path is proposed to take place in the environment provided by hot springs in the presence of snow and ice, thus creating the ‘fire and ice’ conditions. The author guides the reader through several steps that ultimately lead to the beginning of life on our planet as we know it. The journey starts from the delivery of water and organic compounds to the early Earth by comet and asteroid impacts, progressing to the formation of vesicles in geysers, the entrapment of clay particles, amino acids and other ingredients in the vesicles, the formation of template-directed peptides, the elongation to peptides with catalytic activity, the association of catalytic peptides with aromatic compounds (including purines and pyrimidines), peptide catalyzed development of nucleotides, polymerization of nucleotides to RNA, the RNA world, and the stereochemical association with amino acids and peptides into the RNA-peptide world. These steps allow the RNA world to develop a code which forms the basis of the genetic code and ushers in the advent of LUCA. The fiery and icy path to the origin of life is simplified in this book for anyone interested in this intriguing subject.