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.

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 Reactive/Less-cooperative individuals advance population’s synchronization: Modeling of Dictyostelium discoideum concerted signaling during aggregation phase

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259742
Author(s):  
Zahra Eidi ◽  
Najme Khorasani ◽  
Mehdi Sadeghi
Keyword(s):  
Dictyostelium Discoideum ◽  
Life Form ◽  
Single Cells ◽  
Model Organism ◽  
Chemical Signaling ◽  
Relative Population ◽  
Social Amoeba ◽  
The Social ◽  
Chemical Waves ◽  
The Waves

Orchestrated chemical signaling of single cells sounds to be a linchpin of emerging organization and multicellular life form. The social amoeba Dictyostelium discoideum is a well-studied model organism to explore overall pictures of grouped behavior in developmental biology. The chemical waves secreted by aggregating Dictyostelium is a superb example of pattern formation. The waves are either circular or spiral in shape, according to the incremental population density of a self-aggregating community of individuals. Here, we revisit the spatiotemporal patterns that appear in an excitable medium due to synchronization of randomly firing individuals, but with a more parsimonious attitude. According to our model, a fraction of these individuals are less involved in amplifying external stimulants. Our simulations indicate that the cells enhance the system’s asymmetry and as a result, nucleate early sustainable spiral territory zones, provided that their relative population does not exceed a tolerable threshold.

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 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 Amino Acid Repeats Cause Extraordinary Coding Sequence Variation in the Social Amoeba Dictyostelium discoideum

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e46150 ◽  
Author(s):  
Clea Scala ◽  
Xiangjun Tian ◽  
Natasha J. Mehdiabadi ◽  
Margaret H. Smith ◽  
Gerda Saxer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dictyostelium Discoideum ◽  
Sequence Variation ◽  
Social Amoeba ◽  
Coding Sequence ◽  
Amino Acid Repeats ◽  
The Social
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