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Статті в журналах з теми "Mutualiste"

Автор: Grafiati

Опубліковано: 23 вересня 2022

Оновлено: 28 вересня 2022

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1

Sachs, Joel L., Ryan G. Skophammer, Nidhanjali Bansal, and Jason E. Stajich. "Evolutionary origins and diversification of proteobacterial mutualists." Proceedings of the Royal Society B: Biological Sciences 281, no. 1775 (January 22, 2014): 20132146. http://dx.doi.org/10.1098/rspb.2013.2146.

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Mutualistic bacteria infect most eukaryotic species in nearly every biome. Nonetheless, two dilemmas remain unresolved about bacterial–eukaryote mutualisms: how do mutualist phenotypes originate in bacterial lineages and to what degree do mutualists traits drive or hinder bacterial diversification? Here, we reconstructed the phylogeny of the hyperdiverse phylum Proteobacteria to investigate the origins and evolutionary diversification of mutualistic bacterial phenotypes. Our ancestral state reconstructions (ASRs) inferred a range of 34–39 independent origins of mutualist phenotypes in Proteobacteria, revealing the surprising frequency with which host-beneficial traits have evolved in this phylum. We found proteobacterial mutualists to be more often derived from parasitic than from free-living ancestors, consistent with the untested paradigm that bacterial mutualists most often evolve from pathogens. Strikingly, we inferred that mutualists exhibit a negative net diversification rate (speciation minus extinction), which suggests that mutualism evolves primarily via transitions from other states rather than diversification within mutualist taxa. Moreover, our ASRs infer that proteobacterial mutualist lineages exhibit a paucity of reversals to parasitism or to free-living status. This evolutionary conservatism of mutualism is contrary to long-standing theory, which predicts that selection should often favour mutants in microbial mutualist populations that exploit or abandon more slowly evolving eukaryotic hosts.

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2

Riberolles, Brigitte. "Le bilan mutualiste de la mutualité sociale agricole." Revue internationale de l'économie sociale: Recma, no. 294 (2004): 27. http://dx.doi.org/10.7202/1022020ar.

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3

Vidal, Mayra C., Sheng Pei Wang, David M. Rivers, David M. Althoff, and Kari A. Segraves. "Species richness and redundancy promote persistence of exploited mutualisms in yeast." Science 370, no. 6514 (October 15, 2020): 346–50. http://dx.doi.org/10.1126/science.abb6703.

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Mutualisms, or reciprocally beneficial interspecific interactions, constitute the foundation of many ecological communities and agricultural systems. Mutualisms come in different forms, from pairwise interactions to extremely diverse communities, and they are continually challenged with exploitation by nonmutualistic community members (exploiters). Thus, understanding how mutualisms persist remains an essential question in ecology. Theory suggests that high species richness and functional redundancy could promote mutualism persistence in complex mutualistic communities. Using a yeast system (Saccharomyces cerevisiae), we experimentally show that communities with the greatest mutualist richness and functional redundancy are nearly two times more likely to survive exploitation than are simple communities. Persistence increased because diverse communities were better able to mitigate the negative effects of competition with exploiters. Thus, large mutualistic networks may be inherently buffered from exploitation.

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4

Lautman, Albert, and Camille Brouard. "La gouvernance mutualiste." Regards N�52, no. 2 (2017): 163. http://dx.doi.org/10.3917/regar.052.0163.

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5

Koga, Ryuichi, Minoru Moriyama, Naoko Onodera-Tanifuji, Yoshiko Ishii, Hiroki Takai, Masaki Mizutani, Kohei Oguchi, et al. "Single mutation makes Escherichia coli an insect mutualist." Nature Microbiology 7, no. 8 (August 4, 2022): 1141–50. http://dx.doi.org/10.1038/s41564-022-01179-9.

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AbstractMicroorganisms often live in symbiosis with their hosts, and some are considered mutualists, where all species involved benefit from the interaction. How free-living microorganisms have evolved to become mutualists is unclear. Here we report an experimental system in which non-symbiotic Escherichia coli evolves into an insect mutualist. The stinkbug Plautia stali is typically associated with its essential gut symbiont, Pantoea sp., which colonizes a specialized symbiotic organ. When sterilized newborn nymphs were infected with E. coli rather than Pantoea sp., only a few insects survived, in which E. coli exhibited specific localization to the symbiotic organ and vertical transmission to the offspring. Through transgenerational maintenance with P. stali, several hypermutating E. coli lines independently evolved to support the host’s high adult emergence and improved body colour; these were called ‘mutualistic’ E. coli. These mutants exhibited slower bacterial growth, smaller size, loss of flagellar motility and lack of an extracellular matrix. Transcriptomic and genomic analyses of ‘mutualistic’ E. coli lines revealed independent mutations that disrupted the carbon catabolite repression global transcriptional regulator system. Each mutation reproduced the mutualistic phenotypes when introduced into wild-type E. coli, confirming that single carbon catabolite repression mutations can make E. coli an insect mutualist. These findings provide an experimental system for future work on host–microbe symbioses and may explain why microbial mutualisms are omnipresent in nature.

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6

Labbé, Pierrick. "D'une société de secours mutuel locale à une société fraternelle nationale : la transformation du projet social de l’Union Saint-Joseph d’Ottawa (1863-1905)." Mens 11, no. 1 (March 3, 2014): 37–75. http://dx.doi.org/10.7202/1023337ar.

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Cet article examine la transformation de la mutualité canadienne-française à la fin du xixe siècle en analysant le cas de l’Union Saint-Joseph d’Ottawa. Elle fut l’une des rares sociétés de secours mutuel de première génération à adapter sa structure et son projet social pour se conformer au courant mutualiste émergent et, ainsi, se transformer en une société fraternelle. L’exemple nous montre que la lutte pour la survivance dans les milieux de migration facilitait cette transition du modèle mutualiste et justifiait la redéfinition des objectifs par une petite élite au nom d’un idéal national. Le besoin d’assurer des bases institutionnelles solides pour les Canadiens français de l’Ontario légitimait cette transformation de l’Union Saint-Joseph, qui devint une grande société fraternelle vouée à la défense des intérêts économiques des Canadiens français, grâce à l’établissement de succursales dans plus de six cents communautés canadiennes-françaises du Canada et des États-Unis.

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7

Segraves, Kari A., David M. Althoff, and Olle Pellmyr. "Limiting cheaters in mutualism: evidence from hybridization between mutualist and cheater yucca moths." Proceedings of the Royal Society B: Biological Sciences 272, no. 1577 (August 31, 2005): 2195–201. http://dx.doi.org/10.1098/rspb.2005.3201.

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Mutualisms are balanced antagonistic interactions where both species gain a net benefit. Because mutualisms generate resources, they can be exploited by individuals that reap the benefits of the interaction without paying any cost. The presence of such ‘cheaters’ may have important consequences, yet we are only beginning to understand how cheaters evolve from mutualists and how their evolution may be curtailed within mutualistic lineages. The yucca–yucca moth pollination mutualism is an excellent model in this context as there have been two origins of cheating from within the yucca moth lineage. We used nuclear and mitochondrial DNA markers to examine genetic structure in a moth population where a cheater species is parapatric with a resident pollinator. The results revealed extensive hybridization between pollinators and cheaters. Hybrids were genetically intermediate to parental populations, even though all individuals in this population had a pollinator phenotype. The results suggest that mutualisms can be stable in the face of introgression of cheater genes and that the ability of cheaters to invade a given mutualism may be more limited than previously appreciated.

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8

Wooding, Amy L., Michael J. Wingfield, Brett P. Hurley, Jeffrey R. Garnas, Peter de Groot, and Bernard Slippers. "Lack of fidelity revealed in an insect–fungal mutualism after invasion." Biology Letters 9, no. 4 (August 23, 2013): 20130342. http://dx.doi.org/10.1098/rsbl.2013.0342.

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Symbiont fidelity is an important mechanism in the evolution and stability of mutualisms. Strict fidelity has been assumed for the obligate mutualism between Sirex woodwasps and their mutualistic Amylostereum fungi. This assumption has been challenged in North America where the European woodwasp, Sirex noctilio , and its fungal mutualist, Amylostereum areolatum , have recently been introduced. We investigate the specificity of the mutualism between Sirex and Amylostereum species in Canada, where S. noctilio co-infests Pinus with native Sirex nigricornis and its mutualist, Amylostereum chailletii . Using phylogenetic and culture methods, we show that extensive, reciprocal exchange of fungal species and strains is occurring, with 75.3 per cent of S. nigricornis carrying A. areolatum and 3.5 per cent of S. noctilio carrying A. chailletii . These findings show that the apparent specificity of the mutualism between Sirex spp. and their associated Amylostereum spp. is not the result of specific biological mechanisms that maintain symbiont fidelity. Rather, partner switching may be common when shifting geographical distributions driven by ecological or anthropogenic forces bring host and mutualist pairs into sympatry. Such novel associations have potentially profound consequences for fitness and virulence. Symbiont sharing, if it occurs commonly, may represent an important but overlooked mechanism of community change linked to biological invasions.

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9

Fricke, Evan C., Joshua J. Tewksbury, Elizabeth M. Wandrag, and Haldre S. Rogers. "Mutualistic strategies minimize coextinction in plant–disperser networks." Proceedings of the Royal Society B: Biological Sciences 284, no. 1854 (May 10, 2017): 20162302. http://dx.doi.org/10.1098/rspb.2016.2302.

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The global decline of mutualists such as pollinators and seed dispersers may cause negative direct and indirect impacts on biodiversity. Mutualistic network models used to understand the stability of mutualistic systems indicate that species with low partner diversity are most vulnerable to coextinction following mutualism disruption. However, existing models have not considered how species vary in their dependence on mutualistic interactions for reproduction or survival, overlooking the potential influence of this variation on species' coextinction vulnerability and on network stability. Using global databases and field experiments focused on the seed dispersal mutualism, we found that plants and animals that depend heavily on mutualistic interactions have higher partner diversity. Under simulated network disruption, this empirical relationship strongly reduced coextinction because the species most likely to lose mutualists depend least on their mutualists. The pattern also reduced the importance of network structure for stability; nested network structure had little effect on coextinction after simulations incorporated the empirically derived relationship between partner diversity and mutualistic dependence. Our results highlight a previously unknown source of stability in mutualistic networks and suggest that differences among species in their mutualistic strategy, rather than network structure, primarily accounts for stability in mutualistic communities.

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10

Simonsen, Anna K., and John R. Stinchcombe. "Standing genetic variation in host preference for mutualist microbial symbionts." Proceedings of the Royal Society B: Biological Sciences 281, no. 1797 (December 22, 2014): 20142036. http://dx.doi.org/10.1098/rspb.2014.2036.

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Many models of mutualisms show that mutualisms are unstable if hosts lack mechanisms enabling preferential associations with mutualistic symbiotic partners over exploitative partners. Despite the theoretical importance of mutualism-stabilizing mechanisms, we have little empirical evidence to infer their evolutionary dynamics in response to exploitation by non-beneficial partners. Using a model mutualism—the interaction between legumes and nitrogen-fixing soil symbionts—we tested for quantitative genetic variation in plant responses to mutualistic and exploitative symbiotic rhizobia in controlled greenhouse conditions. We found significant broad-sense heritability in a legume host's preferential association with mutualistic over exploitative symbionts and selection to reduce frequency of associations with exploitative partners. We failed to detect evidence that selection will favour the loss of mutualism-stabilizing mechanisms in the absence of exploitation, as we found no evidence for a fitness cost to the host trait or indirect selection on genetically correlated traits. Our results show that genetic variation in the ability to preferentially reduce associations with an exploitative partner exists within mutualisms and is under selection, indicating that micro-evolutionary responses in mutualism-stabilizing traits in the face of rapidly evolving mutualistic and exploitative symbiotic bacteria can occur in natural host populations.

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11

Dreyfus, Michel. "Les grands jalons de l'histoire mutualiste." Vie sociale 4, no. 4 (2008): 11. http://dx.doi.org/10.3917/vsoc.084.0011.

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12

Lobre, Katia. "Radiographie d’un comité d’audit bancaire mutualiste." Management & Avenir 81, no. 7 (2015): 81. http://dx.doi.org/10.3917/mav.081.0081.

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13

Bancel, Jean-Louis. "C'est quoi être mutualiste en 2020 ?" Revue d'économie financière N°134, no. 2 (2019): 21. http://dx.doi.org/10.3917/ecofi.134.0021.

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14

Liordos, Vasilios, Vasileios J. Kontsiotis, Ioanna Eleftheriadou, Stylianos Telidis, and Archimidis Triantafyllidis. "Wildlife Value Orientations and Demographics in Greece." Earth 2, no. 3 (July 22, 2021): 457–67. http://dx.doi.org/10.3390/earth2030027.

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Value orientations can predict attitudes and possibly behaviors. Wildlife value orientations (WVOs) are useful constructs for predicting differences in attitudes among segments of the public towards issues in the wildlife domain. We carried out face-to-face interviews with a representative sample of the Greek population (n = 2392) to investigate two basic WVOs, domination and mutualism and the four WVO types that result from their combination: traditionalist (high domination, low mutualism), mutualist (high mutualism, low domination), distanced (low mutualism, low domination) and pluralist (high mutualism, high domination), and how they relate to sociodemographics. Based on basic WVOs, the Greek population was predominantly mutualism-oriented. The analysis of WVO types also revealed that mutualists were the most abundant (41.0%) followed by the distanced (31.1%). Traditionalists (17.9%) and pluralists (10.0%) occupied smaller proportions of the population. Younger individuals were more mutualist-oriented, while older individuals (>35 years old) were more traditionalist and distanced-oriented. Females were more mutualist than males, the latter being more traditionalist. Those with higher education were more mutualist and less traditionalist and distanced than those with lower education. Pet owners were more mutualist and less distanced than non-pet owners. WVO types did not vary with current residence. The produced knowledge would inform about differences in WVOs among segments of the public and would be therefore useful for implementing successful wildlife conservation and management plans.

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15

Chomicki, Guillaume, and Susanne S. Renner. "Partner abundance controls mutualism stability and the pace of morphological change over geologic time." Proceedings of the National Academy of Sciences 114, no. 15 (March 24, 2017): 3951–56. http://dx.doi.org/10.1073/pnas.1616837114.

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Mutualisms that involve symbioses among specialized partners may be more stable than mutualisms among generalists, and theoretical models predict that in many mutualisms, partners exert reciprocal stabilizing selection on traits directly involved in the interaction. A corollary is that mutualism breakdown should increase morphological rates of evolution. We here use the largest ant-plant clade (Hydnophytinae), with different levels of specialization for mutualistic ant symbionts, to study the ecological context of mutualism breakdown and the response of a key symbiosis-related trait, domatium entrance hole size, which filters symbionts by size. Our analyses support three predictions from mutualism theory. First, all 12 losses apparently only occur from a generalist symbiotic state. Second, mutualism losses occurred where symbionts are scarce, in our system at high altitudes. Third, domatium entrance hole size barely changes in specialized symbiotic species, but evolves rapidly once symbiosis with ants has broken down, with a “morphorate map” revealing that hotspots of entrance hole evolution are clustered in high-altitude areas. Our study reveals that mutualistic strategy profoundly affects the pace of morphological change in traits involved in the interaction and suggests that shifts in partners’ relative abundances may frequently drive reversions of generalist mutualisms to autonomy.

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16

Chomicki, Guillaume, E. Toby Kiers, and Susanne S. Renner. "The Evolution of Mutualistic Dependence." Annual Review of Ecology, Evolution, and Systematics 51, no. 1 (November 2, 2020): 409–32. http://dx.doi.org/10.1146/annurev-ecolsys-110218-024629.

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While the importance of mutualisms across the tree of life is recognized, it is not understood why some organisms evolve high levels of dependence on mutualistic partnerships, while other species remain autonomous or retain or regain minimal dependence on partners. We identify four main pathways leading to the evolution of mutualistic dependence. Then, we evaluate current evidence for three predictions: ( a) Mutualisms with different levels of dependence have distinct stabilizing mechanisms against exploitation and cheating, ( b) less dependent mutualists will return to autonomy more often than those that are highly dependent, and ( c) obligate mutualisms should be less context dependent than facultative ones. Although we find evidence supporting all three predictions, we stress that mutualistic partners follow diverse paths toward—and away from—dependence. We also highlight the need to better examine asymmetry in partner dependence. Recognizing how variation in dependence influences the stability, breakdown, and context dependence of mutualisms generates new hypotheses regarding how and why the benefits of mutualistic partnerships differ over time and space.

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17

Steidinger, Brian S., and James D. Bever. "Host discrimination in modular mutualisms: a theoretical framework for meta-populations of mutualists and exploiters." Proceedings of the Royal Society B: Biological Sciences 283, no. 1822 (January 13, 2016): 20152428. http://dx.doi.org/10.1098/rspb.2015.2428.

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Plants in multiple symbioses are exploited by symbionts that consume their resources without providing services. Discriminating hosts are thought to stabilize mutualism by preferentially allocating resources into anatomical structures (modules) where services are generated, with examples of modules including the entire inflorescences of figs and the root nodules of legumes. Modules are often colonized by multiple symbiotic partners, such that exploiters that co-occur with mutualists within mixed modules can share rewards generated by their mutualist competitors. We developed a meta-population model to answer how the population dynamics of mutualists and exploiters change when they interact with hosts with different module occupancies (number of colonists per module) and functionally different patterns of allocation into mixed modules. We find that as module occupancy increases, hosts must increase the magnitude of preferentially allocated resources in order to sustain comparable populations of mutualists. Further, we find that mixed colonization can result in the coexistence of mutualist and exploiter partners, but only when preferential allocation follows a saturating function of the number of mutualists in a module. Finally, using published data from the fig–wasp mutualism as an illustrative example, we derive model predictions that approximate the proportion of exploiter, non-pollinating wasps observed in the field.

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18

Siney, Charlotte, and Stéphane Barry. "L’union mutualiste de la Gironde et de la région, un prototype d’innovation médico-sociale mutualiste (1921-1945)." Revue internationale de l'économie sociale: Recma, no. 303 (2007): 83. http://dx.doi.org/10.7202/1021549ar.

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19

Wang, Rong, Xiao-Yong Chen, Yan Chen, Gang Wang, Derek W. Dunn, Rupert J. Quinnell, and Stephen G. Compton. "Loss of top-down biotic interactions changes the relative benefits for obligate mutualists." Proceedings of the Royal Society B: Biological Sciences 286, no. 1897 (February 20, 2019): 20182501. http://dx.doi.org/10.1098/rspb.2018.2501.

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The collapse of mutualisms owing to anthropogenic changes is contributing to losses of biodiversity. Top predators can regulate biotic interactions between species at lower trophic levels and may contribute to the stability of such mutualisms, but they are particularly likely to be lost after disturbance of communities. We focused on the mutualism between the fig tree Ficus microcarpa and its host-specific pollinator fig wasp and compared the benefits accrued by the mutualists in natural and translocated areas of distribution. Parasitoids of the pollinator were rare or absent outside the natural range of the mutualists, where the relative benefits the mutualists gained from their interaction were changed significantly away from the plant's natural range owing to reduced seed production rather than increased numbers of pollinator offspring. Furthermore, in the absence of the negative effects of its parasitoids, we detected an oviposition range expansion by the pollinator, with the use of a wider range of ovules that could otherwise have generated seeds. Loss of top-down control has therefore resulted in a change in the balance of reciprocal benefits that underpins this obligate mutualism, emphasizing the value of maintaining food web complexity in the Anthropocene.

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20

Egger, Keith N., and David S. Hibbett. "The evolutionary implications of exploitation in mycorrhizas." Canadian Journal of Botany 82, no. 8 (August 1, 2004): 1110–21. http://dx.doi.org/10.1139/b04-056.

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Some views of mutualism, where the fitness of two symbiotic partners is higher in association than when apart, assume that they necessarily evolve towards greater benefit for the partners. Most mutualisms, however, seem prone to conflicts of interest that destabilize the partnership. These conflicts arise in part because mutualistic outcomes are conditional, depending upon complex interactions between environmental, developmental, and genotypic factors. Mutualisms are also subject to exploitation or cheating. Although various compensating mechanisms have been proposed to explain how mutualism can be maintained in the presence of exploiters, none of these mechanisms can eliminate exploitation. In this paper we explore various compensating mechanisms in mycorrhizas, examine the evidence for exploitation in mycorrhizas, and conclude that mycorrhizal mutualisms exhibit characteristics that are more consistent with a concept of reciprocal parasitism. We propose that researchers should not assume mycorrhizas are mutualistic based upon structural characteristics or limited functional studies showing bilateral exchange and should view mycorrhizas as occupying a wider range on the symbiotic continuum, including commensalism and antagonism. We recommend that comparative studies of mycorrhizas incorporate other types of root associations that have traditionally been considered antagonistic.Key words: mycorrhizas, mutualism, exploiters, compensating mechanisms, symbiotic continuum.

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21

Siney-Lange, Charlotte. "L'avant-gardisme médicosocial mutualiste : retour sur une page blanche de l'histoire de la Mutualité (1850-1945)." Vie sociale 7, no. 3 (2014): 77. http://dx.doi.org/10.3917/vsoc.143.0077.

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22

Shapiro, Jason W., Elizabeth S. C. P. Williams, and Paul E. Turner. "Evolution of parasitism and mutualism between filamentous phage M13 andEscherichia coli." PeerJ 4 (May 24, 2016): e2060. http://dx.doi.org/10.7717/peerj.2060.

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Background.How host-symbiont interactions coevolve between mutualism and parasitism depends on the ecology of the system and on the genetic and physiological constraints of the organisms involved. Theory often predicts that greater reliance on horizontal transmission favors increased costs of infection and may result in more virulent parasites or less beneficial mutualists. We set out to understand transitions between parasitism and mutualism by evolving the filamentous bacteriophage M13 and its hostEscherichia coli.Results.The effect of phage M13 on bacterial fitness depends on the growth environment, and initial assays revealed that infected bacteria reproduce faster and to higher density than uninfected bacteria in 96-well microplates. These data suggested that M13 is, in fact, a facultative mutualist ofE. coli. We then allowedE. coliand M13 to evolve in replicated environments, which varied in the relative opportunity for horizontal and vertical transmission of phage in order to assess the evolutionary stability of this mutualism. After 20 experimental passages, infected bacteria from treatments with both vertical and horizontal transmission of phage had evolved the fastest growth rates. At the same time, phage from these treatments no longer benefited the ancestral bacteria.Conclusions.These data suggest a positive correlation between the positive effects of M13 onE. colihosts from the same culture and the negative effects of the same phage toward the ancestral bacterial genotype. The results also expose flaws in applying concepts from the virulence-transmission tradeoff hypothesis to mutualism evolution. We discuss the data in the context of more recent theory on how horizontal transmission affects mutualisms and explore how these effects influence phages encoding virulence factors in pathogenic bacteria.

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23

Orivel, Jérôme, Pierre-Jean Malé, Jérémie Lauth, Olivier Roux, Frédéric Petitclerc, Alain Dejean, and Céline Leroy. "Trade-offs in an ant–plant–fungus mutualism." Proceedings of the Royal Society B: Biological Sciences 284, no. 1850 (March 15, 2017): 20161679. http://dx.doi.org/10.1098/rspb.2016.1679.

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Анотація:

Species engaged in multiple, simultaneous mutualisms are subject to trade-offs in their mutualistic investment if the traits involved in each interaction are overlapping, which can lead to conflicts and affect the longevity of these associations. We investigate this issue via a tripartite mutualism involving an ant plant, two competing ant species and a fungus the ants cultivate to build galleries under the stems of their host plant to capture insect prey. The use of the galleries represents an innovative prey capture strategy compared with the more typical strategy of foraging on leaves. However, because of a limited worker force in their colonies, the prey capture behaviour of the ants results in a trade-off between plant protection (i.e. the ants patrol the foliage and attack intruders including herbivores) and ambushing prey in the galleries, which has a cascading effect on the fitness of all of the partners. The quantification of partners' traits and effects showed that the two ant species differed in their mutualistic investment. Less investment in the galleries (i.e. in fungal cultivation) translated into more benefits for the plant in terms of less herbivory and higher growth rates and vice versa. However, the greater vegetative growth of the plants did not produce a positive fitness effect for the better mutualistic ant species in terms of colony size and production of sexuals nor was the mutualist compensated by the wider dispersal of its queens. As a consequence, although the better ant mutualist is the one that provides more benefits to its host plant, its lower host–plant exploitation does not give this ant species a competitive advantage. The local coexistence of the ant species is thus fleeting and should eventually lead to the exclusion of the less competitive species.

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24

Hillesland, Kristina L., and David A. Stahl. "Rapid evolution of stability and productivity at the origin of a microbial mutualism." Proceedings of the National Academy of Sciences 107, no. 5 (January 19, 2010): 2124–29. http://dx.doi.org/10.1073/pnas.0908456107.

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Mutualistic interactions are taxonomically and functionally diverse. Despite their ubiquity, however, the basic ecological and evolutionary processes underlying their origin and maintenance are poorly understood. A major reason for this is the lack of an experimentally tractable model system. We examine the evolution of an experimentally imposed obligate mutualism between sulfate-reducing and methanogenic microorganisms that have no known history of previous interaction. Twenty-four independent pairings (cocultures) of the bacterium Desulfovibrio vulgaris and the archaeon Methanococcus maripaludis were established and followed for 300 community doublings in two environments, one allowing for the development of a heterogeneous distribution of resources and the other not. Evolved cocultures grew up to 80% faster and were up to 30% more productive (biomass yield per mole of substrate) than the ancestors. The evolutionary process was marked by periods of significant instability leading to extinction of two of the cocultures, but it resulted in more stable, efficient, and productive mutualisms for most replicated pairings. Comparisons of evolved cocultures with those assembled from one evolved mutualist and one ancestral mutualist showed that evolution of both species contributed to improved productivity. Surprisingly, however, overall improvements in growth rate and yield were less than the sum of the individual contributions, suggesting antagonistic interactions between mutations from the coevolved populations. Physical constraints on the transfer of metabolites in the evolution environment affected the evolution of M. maripaludis, but not of D. vulgaris. Together, these results demonstrate that challenges can imperil nascent obligate mutualisms and demonstrate the evolutionary responses that enable their persistence and future evolution.

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25

Surzur, Jean-Jacques. "Le secteur mutualiste et coopératif financier : quel devenir ?" Revue d'économie financière 67, no. 3 (2002): 261–67. http://dx.doi.org/10.3406/ecofi.2002.3587.

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26

Lapoutte, Alexandrine, and Christian Cadiou. "Gouvernance et entreprise mutualiste : la légitimité en question." Recherches en Sciences de Gestion 101, no. 2 (2014): 175. http://dx.doi.org/10.3917/resg.101.0173.

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27

Jardat, Rémi, and Olivier Boned. "La gouvernance mutualiste face à la crise bancaire." L'Expansion Management Review N° 131, no. 4 (2008): 44. http://dx.doi.org/10.3917/emr.131.0044.

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28

Draperi, Jean-François. "Mesurer l’action coopérative et mutualiste, une question d’organisation ?" Revue internationale de l'économie sociale: Recma, no. 335 (2015): 4. http://dx.doi.org/10.7202/1028527ar.

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29

Werner, Gijsbert D. A., Johannes H. C. Cornelissen, William K. Cornwell, Nadejda A. Soudzilovskaia, Jens Kattge, Stuart A. West, and E. Toby Kiers. "Symbiont switching and alternative resource acquisition strategies drive mutualism breakdown." Proceedings of the National Academy of Sciences 115, no. 20 (April 30, 2018): 5229–34. http://dx.doi.org/10.1073/pnas.1721629115.

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Cooperative interactions among species, termed mutualisms, have played a crucial role in the evolution of life on Earth. However, despite key potential benefits to partners, there are many cases in which two species cease to cooperate and mutualisms break down. What factors drive the evolutionary breakdown of mutualism? We examined the pathways toward breakdowns of the mutualism between plants and arbuscular mycorrhizal fungi. By using a comparative approach, we identify ∼25 independent cases of complete mutualism breakdown across global seed plants. We found that breakdown of cooperation was only stable when host plants (i) partner with other root symbionts or (ii) evolve alternative resource acquisition strategies. Our results suggest that key mutualistic services are only permanently lost if hosts evolve alternative symbioses or adaptations.

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30

Aanen, Duur K. "As you reap, so shall you sow: coupling of harvesting and inoculating stabilizes the mutualism between termites and fungi." Biology Letters 2, no. 2 (January 10, 2006): 209–12. http://dx.doi.org/10.1098/rsbl.2005.0424.

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At present there is no consensus theory explaining the evolutionary stability of mutualistic interactions. However, the question is whether there are general ‘rules’, or whether each particular mutualism needs a unique explanation. Here, I address the ultimate evolutionary stability of the ‘agricultural’ mutualism between fungus-growing termites and Termitomyces fungi, and provide a proximate mechanism for how stability is achieved. The key to the proposed mechanism is the within-nest propagation mode of fungal symbionts by termites. The termites suppress horizontal fungal transmission by consuming modified unripe mushrooms (nodules) for food. However, these nodules provide asexual gut-resistant spores that form the inoculum of new substrate. This within-nest propagation has two important consequences: (i) the mutualistic fungi undergo severe, recurrent bottlenecks, so that the fungus is likely to be in monoculture and (ii) the termites ‘artificially’ select for high nodule production, because their fungal food source also provides the inoculum for the next harvest. I also provide a brief comparison of the termite–fungus mutualism with the analogous agricultural mutualism between attine ants and fungi. This comparison shows that—although common factors for the ultimate evolutionary stability of mutualisms can be identified—the proximate mechanisms can be fundamentally different between different mutualisms.

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31

Bonet, Luc. "Pour une théorie économique mutualiste, profit versus surplus mutuel." Revue internationale de l'économie sociale: Recma, no. 327 (2013): 27. http://dx.doi.org/10.7202/1015148ar.

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32

Femery, Virginie. "Des technologies au service de l’homme : un défi mutualiste ?" Le journal de l'école de Paris du management N°138, no. 4 (2019): 16. http://dx.doi.org/10.3917/jepam.138.0016.

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33

Moisset, Pierre. "S’engager dans une certification qualité, exemple d’un gestionnaire mutualiste." Métiers de la Petite Enfance 25, no. 265 (January 2019): 25–27. http://dx.doi.org/10.1016/j.melaen.2018.10.022.

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34

Bond, Olivier. "Est-il légitime de parler d’identité mutualiste en Europe ?" Revue internationale de l'économie sociale: Recma, no. 299 (2006): 9. http://dx.doi.org/10.7202/1021828ar.

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35

Gano-Cohen, Kelsey A., Camille E. Wendlandt, Khadija Al Moussawi, Peter J. Stokes, Kenjiro W. Quides, Alexandra J. Weisberg, Jeff H. Chang, and Joel L. Sachs. "Recurrent mutualism breakdown events in a legume rhizobia metapopulation." Proceedings of the Royal Society B: Biological Sciences 287, no. 1919 (January 29, 2020): 20192549. http://dx.doi.org/10.1098/rspb.2019.2549.

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Bacterial mutualists generate major fitness benefits for eukaryotes, reshaping the host phenotype and its interactions with the environment. Yet, microbial mutualist populations are predicted to generate mutants that defect from providing costly services to hosts while maintaining the capacity to exploit host resources. Here, we examined the mutualist service of symbiotic nitrogen fixation in a metapopulation of root-nodulating Bradyrhizobium spp . that associate with the native legume Acmispon strigosus . We quantified mutualism traits of 85 Bradyrhizobium isolates gathered from a 700 km transect in California spanning 10 sampled A. strigosus populations. We clonally inoculated each Bradyrhizobium isolate onto A. strigosus hosts and quantified nodulation capacity and net effects of infection, including host growth and isotopic nitrogen concentration. Six Bradyrhizobium isolates from five populations were categorized as ineffective because they formed nodules but did not enhance host growth via nitrogen fixation. Six additional isolates from three populations failed to form root nodules. Phylogenetic reconstruction inferred two types of mutualism breakdown, including three to four independent losses of effectiveness and five losses of nodulation capacity on A. strigosus . The evolutionary and genomic drivers of these mutualism breakdown events remain poorly understood.

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36

Giordano, Florent, Joan Le Goff, and Denis Malherbe. "L’éthique mutualiste est-elle soluble dans le New Public Management ? Le cas d’une union régionale de la Mutualité." Revue française de gestion 41, no. 247 (March 28, 2015): 119–35. http://dx.doi.org/10.3166/rfg.247.119-135.

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37

De Jager, GP, and L. Basson. "Vindingryke silwernitraat-impregneringstegniek vir varswater trigodina-taksonomie." Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 39, no. 1 (February 19, 2021): 119. http://dx.doi.org/10.36303/satnt.2020.39.1.813.

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Trigodinas (Ciliophora: Peritricha) is eensellige, gesilieerde simbionte wat altyd met meersellige akwatiese gashere geassosieer word. Die spesifieke simbiotiese verhouding waarin trigodinas met hul gashere verkeer is nog ’n enigma, met sekere kenners wat hulle as patogene in akwakultuurboerderye bestempel en ander wat hulle as kommensialiste, en in uiterste gevalle selfs as mutualiste, sien.

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38

Lagoutte, Christine. "Le secteur bancaire mutualiste en Grande-Bretagne : enjeux et mutations." Revue internationale de l'économie sociale: Recma, no. 280 (2001): 49. http://dx.doi.org/10.7202/1023668ar.

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Hom, Erik F. Y., and Andrew W. Murray. "Niche engineering demonstrates a latent capacity for fungal-algal mutualism." Science 345, no. 6192 (July 3, 2014): 94–98. http://dx.doi.org/10.1126/science.1253320.

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Mutualistic symbioses shape the evolution of species and ecosystems and catalyze the emergence of biological complexity, yet how such symbioses first form is unclear. We show that an obligate mutualism between the yeastSaccharomyces cerevisiaeand the algaChlamydomonas reinhardtii—two model eukaryotes with very different life histories—can arise spontaneously in an environment requiring reciprocal carbon and nitrogen exchange. This capacity for mutualism is phylogenetically broad, extending to otherChlamydomonasand fungal species. Furthermore, we witnessed the spontaneous association ofChlamydomonasalgal cells physically interacting with filamentous fungi. These observations demonstrate that under specific conditions, environmental change induces free-living species to become obligate mutualists and establishes a set of experimentally tractable, phylogenetically related, synthetic systems for studying the evolution of symbiosis.

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40

Zhang, Ting, K. Charlotte Jandér, Jian-Feng Huang, Bo Wang, Jiang-Bo Zhao, Bai-Ge Miao, Yan-Qiong Peng, and Edward Allen Herre. "The evolution of parasitism from mutualism in wasps pollinating the fig, Ficus microcarpa, in Yunnan Province, China." Proceedings of the National Academy of Sciences 118, no. 32 (August 2, 2021): e2021148118. http://dx.doi.org/10.1073/pnas.2021148118.

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Theory identifies factors that can undermine the evolutionary stability of mutualisms. However, theory’s relevance to mutualism stability in nature is controversial. Detailed comparative studies of parasitic species that are embedded within otherwise mutualistic taxa (e.g., fig pollinator wasps) can identify factors that potentially promote or undermine mutualism stability. We describe results from behavioral, morphological, phylogenetic, and experimental studies of two functionally distinct, but closely related, Eupristina wasp species associated with the monoecious host fig, Ficus microcarpa, in Yunnan Province, China. One (Eupristina verticillata) is a competent pollinator exhibiting morphologies and behaviors consistent with observed seed production. The other (Eupristina sp.) lacks these traits, and dramatically reduces both female and male reproductive success of its host. Furthermore, observations and experiments indicate that individuals of this parasitic species exhibit greater relative fitness than the pollinators, in both indirect competition (individual wasps in separate fig inflorescences) and direct competition (wasps of both species within the same fig). Moreover, phylogenetic analyses suggest that these two Eupristina species are sister taxa. By the strictest definition, the nonpollinating species represents a “cheater” that has descended from a beneficial pollinating mutualist. In sharp contrast to all 15 existing studies of actively pollinated figs and their wasps, the local F. microcarpa exhibit no evidence for host sanctions that effectively reduce the relative fitness of wasps that do not pollinate. We suggest that the lack of sanctions in the local hosts promotes the loss of specialized morphologies and behaviors crucial for pollination and, thereby, the evolution of cheating.

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41

Belot, Roger. "Les spécificités du statut mutualiste dans le secteur des assurances : interview." Revue d'économie financière 67, no. 3 (2002): 193–98. http://dx.doi.org/10.3406/ecofi.2002.3581.

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42

Azéma, Jean. "Le statut mutualiste est-il un frein à la croissance ? : interview." Revue d'économie financière 67, no. 3 (2002): 239–47. http://dx.doi.org/10.3406/ecofi.2002.3585.

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43

Dreyfus, Michel. "La protection sociale libre et volontaire, notamment mutualiste, jusqu’aux années 1930." Vie sociale 10, no. 2 (2015): 17. http://dx.doi.org/10.3917/vsoc.152.0017.

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44

Siney-Lange, Charlotte. "La tuberculose, fondement de l’action médico-sociale mutualiste enseignante (1902-1940)." Revue d'histoire de la protection sociale 1, no. 1 (2008): 79. http://dx.doi.org/10.3917/rhps.001.0079.

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45

Boned, Olivier. "La mondialisation de l’économie induit-elle un gommage de l’identité mutualiste ?" Revue internationale de l'économie sociale: Recma, no. 315 (2010): 90. http://dx.doi.org/10.7202/1020952ar.

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46

Roux, Michel. "Introduction. Entre valeurs et performances : les défis de la finance mutualiste." Revue d'économie financière N°134, no. 2 (2019): 11. http://dx.doi.org/10.3917/ecofi.134.0011.

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47

Marsal, Christine. "La Gouvernance Mutualiste Comme Levier de ContrÔle: Le Cas D'une Banque." Annals of Public and Cooperative Economics 84, no. 1 (February 5, 2013): 83–101. http://dx.doi.org/10.1111/apce.12004.

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48

Biedermann, Peter H. W., and Fernando E. Vega. "Ecology and Evolution of Insect–Fungus Mutualisms." Annual Review of Entomology 65, no. 1 (January 7, 2020): 431–55. http://dx.doi.org/10.1146/annurev-ento-011019-024910.

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The evolution of a mutualism requires reciprocal interactions whereby one species provides a service that the other species cannot perform or performs less efficiently. Services exchanged in insect–fungus mutualisms include nutrition, protection, and dispersal. In ectosymbioses, which are the focus of this review, fungi can be consumed by insects or can degrade plant polymers or defensive compounds, thereby making a substrate available to insects. They can also protect against environmental factors and produce compounds antagonistic to microbial competitors. Insects disperse fungi and can also provide fungal growth substrates and protection. Insect–fungus mutualisms can transition from facultative to obligate, whereby each partner is no longer viable on its own. Obligate dependency has ( a) resulted in the evolution of morphological adaptations in insects and fungi, ( b) driven the evolution of social behaviors in some groups of insects, and ( c) led to the loss of sexuality in some fungal mutualists.

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Beaudet, Thierry, Hélène Delmotte, and Étienne Caniard. "« Nous devons donner envie aux Français de participer à un projet mutualiste »." Les Tribunes de la santé 57, no. 4 (2017): 107. http://dx.doi.org/10.3917/seve.057.0107.

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Souchet, Jean-Luc. "Le mouvement mutualiste dans les évolutions du système de protection sociale français." Vie sociale 4, no. 4 (2008): 103. http://dx.doi.org/10.3917/vsoc.084.0103.

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