scholarly journals Positive linkage between bacterial social traits reveals that homogeneous rather than specialized behavioral repertoires prevail in natural Pseudomonas communities

2018 ◽  
Author(s):  
Jos Kramer ◽  
Miguel Ángel López Carrasco ◽  
Rolf Kümmerli

ABSTRACTBacteria frequently cooperate by sharing secreted metabolites such as enzymes and siderophores. The expression of different ‘public good’ traits can be interdependent, and studies on laboratory systems have shown that such trait linkage affects eco-evolutionary dynamics within bacterial communities. Here, we examine whether linkage among social traits occurs in natural Pseudomonas communities by examining investment levels and correlations between five public goods: biosurfactants, biofilm components, proteases, pyoverdines, and toxic compounds. Our phenotypic assays involving 315 isolates from soil and freshwater communities revealed that their social trait expression profiles varied dramatically, and that correlations between traits were frequent, exclusively positive, and sometimes habitat-specific. Our results indicate that Pseudomonas communities are dominated by isolates lying on a continuum between a ‘social’ type producing multiple public goods, and an ‘asocial’ type showing low investment into social traits. This segregation into different social types could reflect local adaptation to different microhabitats, or emerge from competition between different (social) strategies. Moreover, our results show that isolates with specialized trait repertoires are rare, suggesting limited scope for the mutual exchange of different public goods between isolates. Overall, our work indicates that complex interdependencies among social traits influence the evolution of microbial lifestyles in nature.

2019 ◽  
Vol 96 (1) ◽  
Author(s):  
Jos Kramer ◽  
Miguel Ángel López Carrasco ◽  
Rolf Kümmerli

ABSTRACT Bacteria frequently cooperate by sharing secreted metabolites such as enzymes and siderophores. The expression of such ‘public good’ traits can be interdependent, and studies on laboratory systems have shown that trait linkage affects eco-evolutionary dynamics within bacterial communities. Here, we examine whether linkage among social traits occurs in natural habitats by examining investment levels and correlations between five public goods (biosurfactants, biofilm components, proteases, pyoverdines and toxic compounds) in 315 Pseudomonas isolates from soil and freshwater communities. Our phenotypic assays revealed that (i) social trait expression profiles varied dramatically; (ii) correlations between traits were frequent, exclusively positive and sometimes habitat-specific; and (iii) heterogeneous (specialised) trait repertoires were rarer than homogeneous (unspecialised) repertoires. Our results show that most isolates lie on a continuum between a ‘social’ type producing multiple public goods, and an ‘asocial’ type showing low investment into social traits. This segregation could reflect local adaptation to different microhabitats, or emerge from interactions between different social strategies. In the latter case, our findings suggest that the scope for competition among unspecialised isolates exceeds the scope for mutualistic exchange of different public goods between specialised isolates. Overall, our results indicate that complex interdependencies among social traits shape microbial lifestyles in nature.


2021 ◽  
pp. 116802
Author(s):  
Yongzhao Guo ◽  
Yunpeng Zhao ◽  
Xi Tang ◽  
Tianxing Na ◽  
Juejun Pan ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4127
Author(s):  
Will Farlessyost ◽  
Kelsey-Ryan Grant ◽  
Sara R. Davis ◽  
David Feil-Seifer ◽  
Emily M. Hand

First impressions make up an integral part of our interactions with other humans by providing an instantaneous judgment of the trustworthiness, dominance and attractiveness of an individual prior to engaging in any other form of interaction. Unfortunately, this can lead to unintentional bias in situations that have serious consequences, whether it be in judicial proceedings, career advancement, or politics. The ability to automatically recognize social traits presents a number of highly useful applications: from minimizing bias in social interactions to providing insight into how our own facial attributes are interpreted by others. However, while first impressions are well-studied in the field of psychology, automated methods for predicting social traits are largely non-existent. In this work, we demonstrate the feasibility of two automated approaches—multi-label classification (MLC) and multi-output regression (MOR)—for first impression recognition from faces. We demonstrate that both approaches are able to predict social traits with better than chance accuracy, but there is still significant room for improvement. We evaluate ethical concerns and detail application areas for future work in this direction.


2017 ◽  
Vol 284 (1852) ◽  
pp. 20170200 ◽  
Author(s):  
Roman Popat ◽  
Freya Harrison ◽  
Ana C. da Silva ◽  
Scott A. S. Easton ◽  
Luke McNally ◽  
...  

Bacteria produce a wide variety of exoproducts that favourably modify their environment and increase their fitness. These are often termed ‘public goods’ because they are costly for individuals to produce and can be exploited by non-producers (cheats). The outcome of conflict over public goods is dependent upon the prevailing environment and the phenotype of the individuals in competition. Many bacterial species use quorum sensing (QS) signalling molecules to regulate the production of public goods. QS, therefore, determines the cooperative phenotype of individuals, and influences conflict over public goods. In addition to their regulatory functions, many QS molecules have additional properties that directly modify the prevailing environment. This leads to the possibility that QS molecules could influence conflict over public goods indirectly through non-signalling effects, and the impact of this on social competition has not previously been explored. The Pseudomonas aeruginosa QS signal molecule PQS is a powerful chelator of iron which can cause an iron starvation response. Here, we show that PQS stimulates a concentration-dependent increase in the cooperative production of iron scavenging siderophores, resulting in an increase in the relative fitness of non-producing siderophore cheats. This is likely due to an increased cost of siderophore output by producing cells and a concurrent increase in the shared benefits, which accrue to both producers and cheats. Although PQS can be a beneficial signalling molecule for P. aeruginosa , our data suggest that it can also render a siderophore-producing population vulnerable to competition from cheating strains. More generally, our results indicate that the production of one social trait can indirectly affect the costs and benefits of another social trait.


2018 ◽  
Vol 28 (10) ◽  
pp. 103105 ◽  
Author(s):  
Linjie Liu ◽  
Shengxian Wang ◽  
Xiaojie Chen ◽  
Matjaž Perc

2019 ◽  
Author(s):  
Yongzhao Guo ◽  
Yunpeng Zhao ◽  
Xi Tang ◽  
Tianxing Na ◽  
Juejun Pan ◽  
...  

Abstract Background: Bacterial interaction and communication via quorum sensing (QS) received extensively attention, as it can coordinate bacterial behavior and activity through the QS signal molecules in microbial community. Though the exchange of public goods regulated by QS have been explored in pure culture, how signal sense, transmit, and affect the social traits through regulating public goods in complex communities remains unclear. Results: The levels of public goods (e.g. extracellular polymeric substances (EPS) and amino acids) changed significantly when exogenous diffusion signal factor (DSF), a kind of QS molecules, was added. Approaches involving meta-omics and hierarchical signalling network construction give insight into that anammox species ( Jettenia caeni , AMX1) and Proteobacteria -affiliated bacterium (PRO1) can sense and transit DSF signals, thus directly regulating the production and exchange of public goods via the secondary messenger c-di-GMP regulator, Clp. In detail, these two kinds of species can supply more costly amino acids for DSF-Secretor species (like AMX2, CFX1, CFX3, and PRO4) after sensing DSF. Meanwhile, DSF-Secretor species encoded diverse genes involved in hydrolysis of extracellular protein and carbohydrate and genes involved in transportation of peptides and sugars. The exogenous DSF-inducement also leads to the high expression of these genes, which indicated DSF-Secretor species helped anammox bacteria scavenge extracellular detritus. This process can be considered as a feedback of public goods supply by anammox bacteria, as this process contributed to create a suitable environment for anammox bacteria growth. Namely, DSF can bridge bacterial interactions through regulating public goods. Furthermore, the trade-off induces discrepant metabolic loads of different microbial clusters and community succession. It illustrated the potential to artificially alleviate metabolic loads and thus increase proliferation rate for certain bacteria through QS. Conclusions: DSF can bridge interactions of anammox bacteria and DSF-Secretor species through regulating production and exchange of public goods using Clp regulator. Deciphering microbial interactions via QS provides insights for understanding the molecular evolution of QS in microbial community.


2019 ◽  
Vol 16 (156) ◽  
pp. 20190127 ◽  
Author(s):  
Julián García ◽  
Arne Traulsen

The emergence and maintenance of punishment to protect the commons remains an open puzzle in social and biological sciences. Even in societies where pro-social punishing is common, some individuals seek to cheat the system if they see a chance to do so—and public goods are often maintained in spite of cheaters who do not contribute. We present a model accounting for all possible strategies in a public goods game with punishment. While most models of punishment restrict the set of possible behaviours, excluding seemingly paradoxical anti-social strategies from the start, we show that these strategies can play an important role in explaining large-scale cooperation as observed in human societies. We find that coordinated punishment can emerge from individual interactions, but the stability of the associated institutions is limited owing to anti-social and opportunistic behaviour. In particular, coordinated anti-social punishment can undermine cooperation if individuals cannot condition their behaviour on the existence of institutions that punish. Only when we allow for observability and conditional behaviours do anti-social strategies no longer threaten cooperation. This is due to a stable coexistence of a minority supporting pro-social institutions and those who only cooperate if such institutions are in place. This minority of supporters is enough to guarantee substantial cooperation under a wide range of conditions. Our findings resonate with the empirical observation that public goods are resilient to opportunistic cheaters in large groups of unrelated individuals. They also highlight the importance of letting evolution, and not modellers, decide which strategies matter.


2019 ◽  
Vol 6 (2) ◽  
pp. 181273 ◽  
Author(s):  
Hye Jin Park ◽  
Chaitanya S. Gokhale

Spatial patterns are ubiquitous across different scales of organization in ecological systems. Animal coat pattern, spatial organization of insect colonies and vegetation in arid areas are prominent examples from such diverse ecologies. Typically, pattern formation has been described by reaction–diffusion equations, which consider individuals dispersing between subpopulations of a global pool. This framework applied to public goods game nicely showed the endurance of populations via diffusion and generation of spatial patterns. However, how the spatial characteristics, such as diffusion, are related to the eco-evolutionary process as well as the nature of the feedback from evolution to ecology and vice versa, has been so far neglected. We present a thorough analysis of the ecologically driven evolutionary dynamics in a spatially extended version of ecological public goods games. Furthermore, we show how these evolutionary dynamics feed back into shaping the ecology, thus together determining the fate of the system.


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