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Molecular adaptations to endurance exercise and skeletal muscle fibre plasticity
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Mitochondria have their own DNA because they evolved from prokaryotic organisms that infected eukaryotic cells hundreds of millions of years ago. The endosymbiotic hypothesis states that free-living aerobic bacteria were taken inside a eukaryotic cell and their ability to use oxygen to provide energy meant that the symbiotic pair could combine glycolytic and oxidative metabolism; a huge selective advantage.
Mitochondria and Embryo Viability
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Irene Corachan Garcia, Laura Iñiguez Quiles, Antonio Diez-Juan
New data are continuously improving our understanding of mitochondrial evolution. Two hypotheses exist on the origin of mitochondria. The endosymbiotic hypothesis proposes that the mitochondrion originated after the eukaryotic cell arose; the autogenous hypothesis proposes that this organelle had its beginning at the same time as the cell (3). The endosymbiotic hypothesis is the more widely accepted of the two (3,4). This hypothesis purports that mitochondria were originally prokaryotic cells capable of implementing oxidative mechanisms that later became endosymbionts; initially proposed by Lynn Margulis in 1970, this concept established that mitochondria evolved from free-living bacteria via symbiosis with a eukaryotic host cell (5,6).
Mapping network disturbances
Published in Paul M.W. Hackett, Christopher M. Hayre, Handbook of Ethnography in Healthcare Research, 2020
At night, corals extend their stinging tentacles to catch small floating animals called zooplankton, and the prey is pulled into the corals’ mouths and digested. However, the waters surrounding coral reef ecosystems are known to be nutrient poor, so corals need other ways to supplement their diet. They have entered into a unique relationship with single-celled plant-like organisms called dinoflagellates. Also known as zooxanthellae, the algae live inside coral cells, and here they get energy from photosynthesis. Instead of preserving the organic carbon the algae make, they release up to 95% to their host. The coral animals use this energy to grow, reproduce and build their skeletons. In return, the zooxanthellae receive inorganic nutrients from the waste metabolism of the coral. The coral relies on photosynthesis by zooxanthellae and are thus limited to inhabiting the shallow photic zone where sufficient light is available. This relationship between plant and animal is referred to as mutualistic endosymbiosis because the algae live inside the coral body and both plant and animal benefit from their mutual exchange. It is the microscopic zooxanthellae that live in the translucent tissue of the coral that give the reef skeletons their characteristic brown, green, and purple colors. (Hoegh-Guldberg & Dove, 2019, p. 97; Hopley & Smithers, 2019, p. 10).
Identification of Gut Bacteria such as Lactobacillus johnsonii that Disseminate to Systemic Tissues of Wild Type and MyD88–/– Mice
Published in Gut Microbes, 2022
Sreeram Udayan, Panagiota Stamou, Fiona Crispie, Ana Hickey, Alexandria N. Floyd, Chyi-Song Hsieh, Paul D. Cotter, Orla O’Sullivan, Silvia Melgar, Paul W. O’Toole, Rodney D. Newberry, Valerio Rossini, Ken Nally
Many of the bacteria that we recovered from systemic tissues, have been reported to have beneficial host immunomodulatory effects. L. johnsonii in particular has been reported to reduce proinflammatory responses in murine liver,32 restore normal levels of CD4+ and CD8+ T cells in spleen,33 and trigger differentiation of splenic CD4+ T cells into tumoricidal Th17 cells in cyclophosphamide treated tumor mice.34 Given that we have also found viable L. johnsonii residing in cells and tissues systemically it is tempting to speculate that gut symbionts, such as L. johnsonii, could also function as endosymbionts in order to exert their immunomodulatory effects. For the first time we show that, different bacterial members of the murine gut microbiota, predominantly L. johnsonii, can translocate from the GIT to systemic tissues in WT and MyD88−/− mice. Our stringent and validated culture-dependent approach will be beneficial to identify the cellular and molecular mechanisms underpinning the gut and systemic immunomodulatory effects of gut symbionts and pathobionts, their systemic dissemination, and their contribution to health and disease.
An overview of sex and reproductive immunity from an evolutionary/anthropological perspective
Published in Immunological Medicine, 2021
Yoshihiko Araki, Hiroshi Yoshitake, Kenji Yamatoya, Hiroshi Fujiwara
Nevertheless, life on Earth must coexist with viruses, such as SERS-CoV-2, the cause of the recent pandemic [42]. Viruses may be at odds with life and are clearly not mutually beneficial. This can be said to be an everyday phenomenon in terms of the geological time scale. Before the emergence of sex, eukaryotic cells developed via symbiotic relationships with prokaryotes that became intracellular organelles, according to the endosymbiotic theory [43–45]. Specifically, mitochondria and chloroplasts were derived from aerobic bacteria and cyanobacteria, respectively. Eukaryotes, such as plants and animals, then evolved to undergo sexual reproduction. Furthermore, mammals developed a reproductive strategy that exploits the immune system by acquiring an unusual organ called the placenta, which is possibly the result of a virus being lodged in a mammalian ancestor. What is the destination of human prosperity and evolution through sexual reproduction? If we consider these issues from the perspective of both human cultural and biological histories, we may be able to see a slightly different side to the common sense of the past.
Intestinal Inflammation as a Dysbiosis of Energy Procurement: New Insights into an Old Topic
Published in Gut Microbes, 2021
J. Scott Lee, Ruth X. Wang, Erica E. Alexeev, Sean P. Colgan
Eukaryotes and microbes have long existed in mutually beneficial, symbiotic relationships with one another, relationships thought as fundamental to the development and evolution of multicellular life.2 For instance, an ancestor of modern eukaryotes engulfed an α-proteobacterium capable of oxidative phosphorylation, establishing an endosymbiotic relationship that led to the mitochondria as essential and defining organelles.3 The gut microbiota functions as another organ that resides in the host, albeit of microbial origin. This microbiota consists of organisms of different lineages that communicate with each other and the host, manipulates and redistributes energy, and mediates physiologically vital chemical transformations, providing us with essential functionalities upon which we depend.4 It has long been known that inflammatory bowel disease (IBD) is marked by a state of energy deficiency that involves dysbiosis of the composition and function of the gut microbiota concurrent with a loss of colonic epithelial barrier function.5–7 In this review, we will discuss newer and older literature regarding host- and microbial-derived components that constitute interdependent energy exchanges vital for colonic homeostasis and disease remission.