scholarly journals How Phagocytes Acquired the Capability of Hunting and Removing Pathogens From a Human Body: Lessons Learned From Chemotaxis and Phagocytosis of Dictyostelium discoideum (Review)

2021 ◽  
Vol 9 ◽  
Author(s):  
Xuehua Xu ◽  
Miao Pan ◽  
Tian Jin
Keyword(s):  
Dictyostelium Discoideum ◽  
Pathogenic Bacteria ◽  
White Blood Cells ◽  
Lessons Learned ◽  
The Body ◽  
The Social ◽  
Evolutionarily Conserved ◽  
Unicellular Organisms ◽  
Harmful Organisms ◽  
Social Amoebae

How phagocytes find invading microorganisms and eliminate pathogenic ones from human bodies is a fundamental question in the study of infectious diseases. About 2.5 billion years ago, eukaryotic unicellular organisms–protozoans–appeared and started to interact with various bacteria. Less than 1 billion years ago, multicellular animals–metazoans–appeared and acquired the ability to distinguish self from non-self and to remove harmful organisms from their bodies. Since then, animals have developed innate immunity in which specialized white-blood cells phagocytes- patrol the body to kill pathogenic bacteria. The social amoebae Dictyostelium discoideum are prototypical phagocytes that chase various bacteria via chemotaxis and consume them as food via phagocytosis. Studies of this genetically amendable organism have revealed evolutionarily conserved mechanisms underlying chemotaxis and phagocytosis and shed light on studies of phagocytes in mammals. In this review, we briefly summarize important studies that contribute to our current understanding of how phagocytes effectively find and kill pathogens via chemotaxis and phagocytosis.

scholarly journals Comparative genomics of the social amoebae Dictyostelium discoideum and Dictyostelium purpureum

2011 ◽  
Vol 12 (2) ◽  
pp. R20 ◽  
Author(s):  
Richard Sucgang ◽  
Alan Kuo ◽  
Xiangjun Tian ◽  
William Salerno ◽  
Anup Parikh ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Dictyostelium Discoideum ◽  
The Social ◽  
Dictyostelium Purpureum ◽  
Social Amoebae

scholarly journals Exposure to dense bacteria lawns does not cause the social amoeba Dictyostelium discoideum to carry bacteria through the social stage

2017 ◽  
Author(s):  
Debra A Brock ◽  
Alicia Canas ◽  
Kai Jones ◽  
David C Queller ◽  
Joan E Strassmann
Keyword(s):  
Dictyostelium Discoideum ◽  
Associated Bacteria ◽  
Social Amoeba ◽  
Future Studies ◽  
Bacterial Cultures ◽  
Large Numbers ◽  
The Social ◽  
External Forces ◽  
Social Amoebae ◽  
Food Bacteria

Background. Interactions between eukaryotic amoebae and bacteria are understudied and important. Bacteria inside of amoebae are protected from external forces including antibiotics. An excellent model for bacteria-amoeba interactions is the social amoeba Dictyostelium discoideum and its associated bacteria. A third of wild-collected clones of the soil-dwelling amoeba Dictyostelium discoideum exhibit a suite of characteristics that make them simple farmers of bacteria. They carry bacteria internally through the social spore-making stage. They then release these bacteria to grow and subsequently eat them, prudently stopping before they are entirely consumed so some bacteria can be carried to the next generation. D. discoideum defend their food bacteria with other inedible bacteria that produce compounds toxic to non-farmers. Both carried bacteria and social amoeba hosts have demonstrated co-evolved characteristics. Most farmer clones discovered to date carry inedible Burkholderia in addition to food bacteria, but it is not clear whether or not a preponderance of naïve bacteria might induce the farming state by overwhelming the phagocytic actions of the host amoebae. In this study we address this question with D. discoideum clones that naturally carry bacteria and those that do not. Will naïve bacteria in large numbers succeed in colonizing the amoebae? Methods. We grew five non-farmer clones and five farmer clones of wild-collected Dictyostelium discoideum on three different concentrations of a highly palatable bacterial food source, Klebsiella pneumoniae. We then tested them to see if they carried bacteria through the social stage. Results. We found that bacterial density did not have a significant effect on whether or not the clones carried bacteria through the social stage. Even those grown in very dense bacterial cultures were able to shed them successfully unless they were also carrying Burkholderia. Discussion. Our results indicate that even a preponderance of food bacteria cannot overwhelm the ability of social amoebae to digest and not carry bacteria. Apparently, only the inedible Burkholderia have that effect. This points to the importance of understanding co-infection with multiple bacteria because those that cannot induce carriage can nevertheless become carried, foiling digestive processes, but only in the presence of another bacterium. Future studies of host bacteria interactions should consider using multiple bacteria simultaneously.

scholarly journals Symbiont location, host fitness, and possible coadaptation in a symbiosis between social amoebae and bacteria

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Longfei Shu ◽  
Debra A Brock ◽  
Katherine S Geist ◽  
Jacob W Miller ◽  
David C Queller ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
Host Responses ◽  
Bacterial Symbionts ◽  
Disease Dynamics ◽  
Fitness Costs ◽  
Social Amoeba ◽  
Host Fitness ◽  
The Social ◽  
Natural Isolates ◽  
Social Amoebae

Recent symbioses, particularly facultative ones, are well suited for unravelling the evolutionary give and take between partners. Here we look at variation in natural isolates of the social amoeba Dictyostelium discoideum and their relationships with bacterial symbionts, Burkholderia hayleyella and Burkholderia agricolaris. Only about a third of field-collected amoebae carry a symbiont. We cured and cross-infected amoebae hosts with different symbiont association histories and then compared host responses to each symbiont type. Before curing, field-collected clones did not vary significantly in overall fitness, but infected hosts produced morphologically different multicellular structures. After curing and reinfecting, host fitness declined. However, natural B. hayleyella hosts suffered fewer fitness costs when reinfected with B. hayleyella, indicating that they have evolved mechanisms to tolerate their symbiont. Our work suggests that amoebae hosts have evolved mechanisms to tolerate specific acquired symbionts; exploring host-symbiont relationships that vary within species may provide further insights into disease dynamics.

scholarly journals Cooperative predation in the social amoebae Dictyostelium discoideum

PLoS ONE ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. e0209438
Author(s):  
Michelle Rubin ◽  
Amber D. Miller ◽  
Mariko Katoh-Kurasawa ◽  
Christopher Dinh ◽  
Adam Kuspa ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
The Social ◽  
Social Amoebae

scholarly journals Microbiome management in the social amoeba Dictyostelium discoideum compared to humans

2019 ◽  
Vol 63 (8-9-10) ◽  
pp. 447-450 ◽  
Author(s):  
Timothy Farinholt ◽  
Christopher Dinh ◽  
Adam Kuspa
Keyword(s):  
Recent Work ◽  
Dictyostelium Discoideum ◽  
Immune Cells ◽  
Molecular Mechanisms ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Social Amoeba ◽  
The Social ◽  
Physical Barriers ◽  
Social Amoebae

Social amoebae and humans use common strategies to orchestrate their interactions with the bacteria in their respective environments and within their bodies. These strategies include the elimination of bacteria by phagocytosis, the establishment of mutualistic interactions, the elaboration of physical barriers, and the deployment of innate immune cells. Many of the molecular mechanisms that humans and social amoebae employ differ, but there are striking similarities that may inform studies in each organism. In this topical review we highlight the similarities and consider what we might learn by comparing these highly divergent species. We focus on recent work in Dictyostelium discoideum with hopes of stimulating work in this area and with the expectation that new mechanistic details uncovered in social amoebae-bacteria interactions will inform microbiome management in humans.

scholarly journals Sentinel cells, symbiotic bacteria and toxin resistance in the social amoeba Dictyostelium discoideum

2016 ◽  
Vol 283 (1829) ◽  
pp. 20152727 ◽  
Author(s):  
Debra A. Brock ◽  
W. Éamon Callison ◽  
Joan E. Strassmann ◽  
David C. Queller
Keyword(s):  
Dictyostelium Discoideum ◽  
Pathogenic Bacteria ◽  
Spore Production ◽  
Symbiotic Bacteria ◽  
Beneficial Bacteria ◽  
Social Amoeba ◽  
Toxin Resistance ◽  
Cell Numbers ◽  
Diminished Capacity ◽  
The Social

The social amoeba Dictyostelium discoideum is unusual among eukaryotes in having both unicellular and multicellular stages. In the multicellular stage, some cells, called sentinels, ingest toxins, waste and bacteria. The sentinel cells ultimately fall away from the back of the migrating slug, thus removing these substances from the slug. However, some D. discoideum clones (called farmers) carry commensal bacteria through the multicellular stage, while others (called non-farmers) do not. Farmers profit from their beneficial bacteria. To prevent the loss of these bacteria, we hypothesize that sentinel cell numbers may be reduced in farmers, and thus farmers may have a diminished capacity to respond to pathogenic bacteria or toxins. In support, we found that farmers have fewer sentinel cells compared with non-farmers. However, farmers produced no fewer viable spores when challenged with a toxin. These results are consistent with the beneficial bacteria Burkholderia providing protection against toxins. The farmers did not vary in spore production with and without a toxin challenge the way the non-farmers did, which suggests the costs of Burkholderia may be fixed while sentinel cells may be inducible. Therefore, the costs for non-farmers are only paid in the presence of the toxin. When the farmers were cured of their symbiotic bacteria with antibiotics, they behaved just like non-farmers in response to a toxin challenge. Thus, the advantages farmers gain from carrying bacteria include not just food and protection against competitors, but also protection against toxins.

scholarly journals Sex Determination in the Social Amoeba Dictyostelium discoideum

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1533-1536 ◽  
Author(s):  
Gareth Bloomfield ◽  
Jason Skelton ◽  
Alasdair Ivens ◽  
Yoshimasa Tanaka ◽  
Robert R. Kay
Keyword(s):  
Sex Determination ◽  
Dictyostelium Discoideum ◽  
Genetic Locus ◽  
Model Organism ◽  
Mating Types ◽  
Type Locus ◽  
Social Amoeba ◽  
The Third ◽  
The Social ◽  
Social Amoebae

The genetics of sex determination remain mysterious in many organisms, including some that are otherwise well studied. Here we report the discovery and analysis of the mating-type locus of the model organism Dictyostelium discoideum. Three forms of a single genetic locus specify this species' three mating types: two versions of the locus are entirely different in sequence, and the third resembles a composite of the other two. Single, unrelated genes are sufficient to determine two of the mating types, whereas homologs of both these genes are required in the composite type. The key genes encode polypeptides that possess no recognizable similarity to established protein families. Sex determination in the social amoebae thus appears to use regulators that are unrelated to any others currently known.

scholarly journals Exposure to dense bacteria lawns does not cause the social amoeba Dictyostelium discoideum to carry bacteria through the social stage

2017 ◽  
Author(s):  
Debra A Brock ◽  
Alicia Canas ◽  
Kai Jones ◽  
David C Queller ◽  
Joan E Strassmann
Keyword(s):  
Dictyostelium Discoideum ◽  
Associated Bacteria ◽  
Social Amoeba ◽  
Future Studies ◽  
Bacterial Cultures ◽  
Large Numbers ◽  
The Social ◽  
External Forces ◽  
Social Amoebae ◽  
Food Bacteria

Background. Interactions between eukaryotic amoebae and bacteria are understudied and important. Bacteria inside of amoebae are protected from external forces including antibiotics. An excellent model for bacteria-amoeba interactions is the social amoeba Dictyostelium discoideum and its associated bacteria. A third of wild-collected clones of the soil-dwelling amoeba Dictyostelium discoideum exhibit a suite of characteristics that make them simple farmers of bacteria. They carry bacteria internally through the social spore-making stage. They then release these bacteria to grow and subsequently eat them, prudently stopping before they are entirely consumed so some bacteria can be carried to the next generation. D. discoideum defend their food bacteria with other inedible bacteria that produce compounds toxic to non-farmers. Both carried bacteria and social amoeba hosts have demonstrated co-evolved characteristics. Most farmer clones discovered to date carry inedible Burkholderia in addition to food bacteria, but it is not clear whether or not a preponderance of naïve bacteria might induce the farming state by overwhelming the phagocytic actions of the host amoebae. In this study we address this question with D. discoideum clones that naturally carry bacteria and those that do not. Will naïve bacteria in large numbers succeed in colonizing the amoebae? Methods. We grew five non-farmer clones and five farmer clones of wild-collected Dictyostelium discoideum on three different concentrations of a highly palatable bacterial food source, Klebsiella pneumoniae. We then tested them to see if they carried bacteria through the social stage. Results. We found that bacterial density did not have a significant effect on whether or not the clones carried bacteria through the social stage. Even those grown in very dense bacterial cultures were able to shed them successfully unless they were also carrying Burkholderia. Discussion. Our results indicate that even a preponderance of food bacteria cannot overwhelm the ability of social amoebae to digest and not carry bacteria. Apparently, only the inedible Burkholderia have that effect. This points to the importance of understanding co-infection with multiple bacteria because those that cannot induce carriage can nevertheless become carried, foiling digestive processes, but only in the presence of another bacterium. Future studies of host bacteria interactions should consider using multiple bacteria simultaneously.

Fictions of the Human Right to Health: Writing Against the Postcolonial Exotic in Western Medicine

2018 ◽  
Author(s):  
Rosemary J. Jolly
Keyword(s):  
Health Research ◽  
Western Medicine ◽  
Scientific Method ◽  
Medical Humanities ◽  
Right To Health ◽  
The Body ◽  
Health And Wellness ◽  
Human Right ◽  
Cultural Specificity ◽  
The Social

The last decade has witnessed far greater attention to the social determinants of health in health research, but literary studies have yet to address, in a sustained way, how narratives addressing issues of health across postcolonial cultural divides depict the meeting – or non-meeting – of radically differing conceptualisations of wellness and disease. This chapter explores representations of illness in which Western narrators and notions of the body are juxtaposed with conceptualisations of health and wellness entirely foreign to them, embedded as the former are in assumptions about Cartesian duality and the superiority of scientific method – itself often conceived of as floating (mysteriously) free from its own processes of enculturation and their attendant limits. In this respect my work joins Volker Scheid’s, in this volume, in using the capacity of critical medical humanities to reassert the cultural specificity of what we have come to know as contemporary biomedicine, often assumed to be

Sign in / Sign up

Export Citation Format

Share Document