Parasitism is a tight association between species in which one organism, the parasite, lives on or inside the host, causing it harm, and is structurally adapted to this way of life. Until the twenty-first century, parasitism was studied by parasitologists, rather than ecologists or evolutionary biologists. Today, parasitism is a major element of evolutionary ecology, as nearly all free-living animals are hosts to at least one parasite species. Since it is in the parasite's evolutionary interest for its host to flourish, long-term coevolution can lead to a stable relationship bordering on mutualism. According to Lynn Margulis, when resources are scarce, natural selection, moves relationships from parasitism to mutualism, as it was brilliantly illustrated in Margulis' endosymbiosis theory, where eukaryotic mitochondria and chloroplasts descended from formerly free-living prokaryotes. Boundary between mutualism, symbiosis, and pathological parasitism is a thin red line that frequently overlapping without a theory enough clear to explain this thigh relationship between the parasite and its host.

Bacteria are among the earliest forms of life on Earth. Notwithstanding their small size and primitive origin, bacteria still have a tremendous impact on everyday human life. Over the centuries, research into bacteria have provided and enriched the fundamental biological knowledge due to their readily measured processes and effects on higher organisms. Although molecular genetics and microbiology were among the scientific fields that have mostly benefited from the discoveries made in bacteria, our current state of knowledge has gone beyond what anyone could have ever imagined. The present Research Topic aims to cover new and exciting broad aspects of the importance of bacteria to human life, both positive and negative influences. Regulation of bacterial gene expression, replication and segregation control mechanisms, cell to cell communication via quorum sensors, and the relatively recent finding of bacterial immunity via CRISPR, have led to the development of many, and very important new tools in biotechnology and the emerging field of molecular medicine. The battle against infectious diseases has also benefited from the genetic approaches that have been developed in the quest for finding new targets and novel drugs against pathogenic bacteria. At the next level, the human microbiome project has opened up new avenues in understanding the role of bacteria in human health and wellbeing. Finally, the relationship between bacterial infections and human cancers will also be covered, a subject that is still under verification through rigorous experimental approaches. Special emphasis will be given to the bacterial accessory genome, i.e the mobilome, as the primary cause of health-threatening antimicrobial resistance and the production of toxins and virulence factors. Taking into account the evolutionary importance of horizontal gene transfer and the additional beneficial roles of certain bacterial mobile genetic elements, they help project best “the Good, the Bad and the Ugly” outline of this topic. At the time this eBook is about to be published, our Research Topic has registered nearly 55, 000 views.

The good, the bad, the ugly.

This is the authoritative resource on IBS. In this easy to read book you will discover what actually causes IBS; how to find the cause of your own symptoms; how to treat your symptoms; and where to go for help. If you have IBS, constipation, diarrhea, gas, bloating, indigestion, or chronic abdominal pain, there is a logical reason for your suffering. Written by Dr. Stephen Wangen, the founder of the IBS Treatment Center, this book explains how your symptoms can be cured. You do not need to eat more fiber; take medications or supplements for the rest of your life; or wonder if you are too stressed. You can actually live your life completely free of IBS and this book will help you discover how.

An ever-growing roster of model organisms is a hallmark of 21st century Developmental Biology. Emerging model organisms are well suited to asking some fascinating and important questions that cannot be addressed using established model systems. And new methods are increasingly facilitating the adoption of new research organisms in laboratories. This volume is written by some of the scientists who have played pivotal roles in developing new models or in significantly advancing tools in emerging systems. - Presents some of the most interesting additions to the core set of model organisms - Contains contributions from people who have developed new model systems or advanced tools - Includes personal stories about how and why model systems were developed

This book describes the state-of-the-art concerning the ‘marine microbiome’ and its uses in biotechnology. The first part discusses the diversity and ecology of marine microorganisms and viruses, including all three domains of life: Bacteria, Archaea, and Eukarya. It discusses whether marine microorganisms exist and, if so, why they might be unique. The second part presents selected marine habitats, their inhabitants and how they influence biogeochemical cycles, while the third discusses the utilization of marine microbial resources, including legal aspects, dissemination, and public awareness. The marine microbiome is the total of microorganisms and viruses in the ocean and seas and in any connected environment, including the seafloor and marine animals and plants. The diversity of microbial life remains unquantified and largely unknown, and could represent a hidden treasure for human society. Accordingly, this book is also intended to connect academics and industry, providing essential information for microbiologists from both fields.