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An Introduction to Parasitism
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Symbiosis refers to an intimate association between organisms of two different species. Parasitism is but one category of symbiotic associations. In the manner most commonly used today, symbiosis embraces many kinds of intimate relationships (Figure 1.11), ranging from phoresy (mostly associated with purposes of transport), to those that clearly benefit one partner without obviously affecting another (commensalism), to mutually beneficial (mutualism), to those that harm one partner at another’s expense (for example, parasitism or predation).
Host-Parasite Relationships
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Parasitism is a life-style that has been adopted by a wide range of types of organisms. In the usage of the term followed in this book, parasitism is a subdivision of the broad term symbiosis which simply means living together. Parasitism in this usage carries an implication of actual or potential harm to one member of the symbiotic pair, the one designated the host.
Streptomyces: A Potential Source of Natural Antimicrobial Drug Leads
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Mahmoud A. Elfaky, Hanaa Nasr, Ilham Touiss, Mohamed L. Ashour
Symbiosis can be defined as any kind of close or interaction between two dissimilar organisms shaped by selective pressures. One organism (usually a bacterium or fungus) produces small bioactive molecules that affect the host in symbiosis (possibly other symbionts). Mutualistic, commensalism and parasitic symbioses exist. The genetic machinery available to the small molecule creator is essential for symbiosis (Seipke et al. 2012).
Circulating microbiome in patients with portal hypertension
Published in Gut Microbes, 2022
Rolandas Gedgaudas, Jasmohan S Bajaj, Jurgita Skieceviciene, Greta Varkalaite, Gabija Jurkeviciute, Sigita Gelman, Irena Valantiene, Romanas Zykus, Andrius Pranculis, Corinna Bang, Andre Franke, Christoph Schramm, Juozas Kupcinskas
Our data show that bacterial DNA can be detected in human plasma samples from healthy individuals. This suggests that certain gut bacteria may translocate via blood at any given time. We speculate that the immune system of healthy individuals is able to contain the translocating bacteria without causing any systemic effect. It is well known that symbiosis with intestinal microorganisms is important for tissue and immunity development47 and metabolic functions,48 and it provides protection against various pathogens.49 While several studies have linked circulating microbiome with diseases, such as alcoholic hepatitis,14 rheumatoid arthritis,17 and cardiovascular disorders,50 it remains difficult to define potentially risky strains in the circulating microbiome as only a limited number of studies have explored microbiome compositional changes in the blood.12 Based on the results of our current study and those of previously reported pathophysiological mechanisms,51 genera such as Escherichia/Shigella or Prevotella may act as TLR4 agonists or ligands for inflammasome activation and activate pathways leading to a pro-inflammatory state of cirrhosis.34,40,52
Neglecting the ecosystemic dimension of life hinders efficient environmental protection from radiation and other hazards
Published in International Journal of Radiation Biology, 2022
If biology describes processes of life at molecular up to organisms level whithin a time scale coherent with organisms, ecology expands this knowledge to the larger space and time scales of populations and ecosystems level. One new process of interaction that emerges at the ecosystem level is symbiosis. Since the beginning of multicellular life evolution, living organisms could evolve only as part of ecosystems because their populations all rely upon symbiotic relationships for their long-term maintenance. Ecosystems actually drive the sustainability of life through symbiotic interspecies relationships. In order to be appropriate, concepts for environmental protection and risk assessment in the context of pollutants do require a much better understanding of ecosystem attibutes, processes and functioning, in addition to pure toxicological understanding. Following this reasoning, environment protection, therefore, is an issue of ecology (ecosystems) as much as an issue of biology (organisms), as it is concerned with the maintenance of these high level symbiotic relationships.
Minimal selfhood
Published in Journal of Neurogenetics, 2020
Self-reproduction denotes processes of multiplication such as the division of cells and the replication of genetic macromolecules. These two phenomena happen to be associated in our present-day biology, yet alternative scenarios are conceivable. Indeed, viruses exemplify replication without self-maintenance insofar as they have to hijack extraneous metabolic systems; that is they have to parasitize another, different self with its own, conflicting interests. Accordingly, viruses are best considered merely self-like. By contrast with such parasitism, symbiosis implies the attainment of consensus among constituent sub-selves. For example, the higher-level selfhood of a eukaryotic cell implies that the host cell and its component mitochondria – formerly free-living bacteria in their own right – have in large measure come to ‘share’ their interests and thus their selfhood (on viruses and other intracellular parasites and symbionts see Glasgow, 2017, p. 147–89).