Christian Kost

Christian Kost
Osnabrück Universität

Prof. Dr.

About

91
Publications
15,961
Reads
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4,680
Citations
Citations since 2016
49 Research Items
2917 Citations
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
Additional affiliations
January 2009 - present
Max Planck Institute for Chemical Ecology
Position
  • Group Leader

Publications

Publications (91)
Article
Full-text available
Explaining the de novo evolution of obligate cooperative cross-feeding interactions among bacteria is a fundamental problem. A critical step during this process is the emergence of reciprocity among two interaction partners, because a mutually beneficial exchange of metabolic byproducts can subsequently favour the evolution of cooperative cross-fee...
Article
Full-text available
Microorganisms mainly exist within complex networks of ecological interactions. Given that the growth and survival of community members frequently depend on an obligate exchange of essential metabolites, it is generally unclear how such communities can persist despite the destabilising force of ecological disturbance. Here we address this issue usi...
Preprint
Full-text available
Human activities increasingly result in a fragmentation of natural ecosystems. However, the ecological consequences of fragmentation remain poorly understood. While some studies report that fragmentation may enhance population growth, others suggest the opposite pattern. Here we investigated how habitat connectivity affects the population size of a...
Preprint
Full-text available
Preparing your offspring for future challenges via priming can directly enhance its fitness. However, evidence for transgenerational priming has been limited to eukaryotic organisms. Here we test the hypothesis that predation primes bacteria such that their future generations respond with a more effective defence induction. In an evolution experime...
Article
Full-text available
Individual-based modeling is widely applied to investigate the ecological mechanisms driving microbial community dynamics. In such models, the population or community dynamics emerge from the behavior and interplay of individual entities, which are simulated according to a predefined set of rules. If the rules that govern the behavior of individual...
Article
Full-text available
Cooperative mutualisms are widespread and play fundamental roles in many ecosystems. Given that these interactions are often obligate, the Darwinian fitness of the participating individuals is not only determined by the information encoded in their own genomes, but also the traits and capabilities of their corresponding interaction partners. Thus,...
Article
The exchange of metabolites among different bacterial genotypes profoundly impacts the structure and function of microbial communities. However, the factors governing the establishment of these cross-feeding interactions remain poorly understood. While shared physiological features may facilitate interactions among more closely related individuals,...
Article
Full-text available
Bacteria frequently engage in obligate metabolic mutualisms with other microorganisms. However, it remains generally unclear how the resulting metabolic dependencies affect the ecological niche space accessible to the whole consortium relative to the niche space available to its constituent individuals. Here we address this issue by systematically...
Preprint
Full-text available
Ecological interactions are key drivers of evolutionary change. Although it is well-documented that antagonistic coevolution can accelerate molecular evolution, the evolutionary consequences of synergistic coevolution remain poorly understood. Here we show experimentally that also synergistic coevolution can speed up the rate of molecular evolution...
Preprint
Full-text available
Cooperative mutualisms are widespread in nature and play fundamental roles in many ecosystems. Due to the often obligate nature of these interactions, the Darwinian fitness of the participating individuals is not only determined by the information encoded in their own genomes, but also the traits and capabilities of their corresponding interaction...
Preprint
Full-text available
Bacteria frequently engage in obligate metabolic mutualisms with other microorganisms. However, it remains generally unclear how the resulting metabolic dependencies affect the ecological niche space accessible to the whole consortium relative to the niche space available to its constituent individuals. Here we address this issue by systematically...
Preprint
Full-text available
The exchange of metabolites among different bacterial genotypes profoundly impacts the structure and function of microbial communities. However, the factors governing the establishment of these cross-feeding interactions remain poorly understood. While shared physiological features may facilitate interactions among more closely related individuals,...
Article
Mutually beneficial interactions are ubiquitous in nature and have played a pivotal role for the evolution of life on earth. However, the factors facilitating their emergence remain poorly understood. Here, we address this issue both experimentally and by mathematical modeling using cocultures of auxotrophic strains of Escherichia coli, whose growt...
Preprint
Full-text available
Microorganisms mainly exist within complex networks of ecological interactions. Given that the growth and survival of community members frequently depend on an obligate exchange of essential metabolites, it is generally unclear how such communities can persist despite the destabilizing force of ecological disturbance. Here we address this issue usi...
Article
Smmary Insects frequently harbor multiple symbionts that collectively provide them with essential nutrients. Comparing several recent and ancient associations revealed a strikingly parallel pattern, by which a new symbiont was integrated into a preexisting host–symbiont interaction.
Article
Bacteria are widely used for commercially producing biomolecules. However, attempts to rationally design production strains and optimize cultivation conditions are frequently counteracted by the emergence of mutants with reduced production characteristics that decrease overall process yield. The reason why these mutants arise is likely because of a...
Article
In order to survive and reproduce, organisms must perform a multitude of tasks. However, trade-offs limit their ability to allocate energy and resources to all of these different processes. One strategy to solve this problem is to specialize in some traits and team up with other organisms that can help by providing additional, complementary functio...
Article
Full-text available
Extrachromosomal genetic elements such as bacterial endosymbionts and plasmids generally exhibit AT-contents that are increased relative to their hosts' DNA. The AT-bias of endosymbiotic genomes is commonly explained by neutral evolutionary processes such as a mutational bias towards increased A+T. Here we show experimentally that an increased AT-c...
Article
Bacteria frequently engage in cross‐feeding interactions that involve an exchange of metabolites with other micro‐ or macroorganisms. The often obligate nature of these associations, however, hampers manipulative experiments, thus limiting our mechanistic understanding of the ecophysiological consequences that result for the organisms involved. Her...
Preprint
Full-text available
Extrachromosomal genetic elements generally exhibit increased AT-contents relative to their hosts’ DNA. The AT-bias of endosymbiotic genomes is commonly explained by neutral evolutionary processes. Here we show experimentally that an increased AT-content of host-dependent elements can be selectively favoured on the host level. Manipulating the nucl...
Article
Full-text available
Literature covered: early 2000s to late 2017 Bacteria frequently exchange metabolites with other micro- and macro-organisms. In these often obligate cross-feeding interactions, primary metabolites such as vitamins, amino acids, nucleotides, or growth factors are exchanged. The widespread distribution of this type of metabolic interactions, however,...
Preprint
Full-text available
Bacteria frequently engage in cross-feeding interactions that involve an exchange of metabolites with other micro- or macroorganisms. The often obligate nature of these associations, however, hampers manipulative experiments, thus limiting our mechanistic understanding of the ecophysiological consequences that result for the organisms involved. Her...
Article
Endosymbionts are organisms that live inside the cells of other species. This lifestyle is ubiquitous across the tree of life and is featured by unicellular eukaryotes, prokaryotes, and by extrachromosomal genetic elements such as plasmids. Given that all of these elements dwell in the cytoplasm of their host cell, they should be subject to similar...
Article
The competent state is a developmentally distinct phase, in which bacteria are able to take up and integrate exogenous DNA into their genome. Bacillus subtilis is one of the naturally competent bacterial species and the domesticated laboratory strain 168 is easily transformable. In this study, we report a reduced transformation frequency of B. subt...
Preprint
Full-text available
The competent state is a developmentally distinct phase, in which bacteria are able to take up and integrate exogenous DNA into their genome. Bacillus subtilis is one of the naturally competent bacterial species and the domesticated laboratory strain 168 is easily transformable. In this study, we report a reduced transformation frequency of B. subt...
Article
The majority of known bacterial species cannot be cultivated under laboratory conditions. Here we argue that the adaptive emergence of obligate metabolic interactions in natural bacterial communities can explain this pattern. Bacteria commonly release metabolites into the external environment. Accumulating pools of extracellular metabolites create...
Article
Full-text available
Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta-analysis to characterize patterns of covariation in CCDs and ide...
Article
Nutritional symbionts play a major role in the ecology and evolution of insects. The recent accumulation of knowledge on the identity, function, genomics, and phylogenetic relationships of insect-bacteria symbioses provides the opportunity to assess the effects of symbiont acquisitions and replacements on the shift into novel ecological niches and...
Article
Full-text available
Bacteria frequently lose biosynthetic genes, thus making them dependent on an environmental uptake of the corresponding metabolite. Despite the ubiquity of this ‘genome streamlining’, it is generally unclear whether the concomitant loss of biosynthetic functions is favored by natural selection or rather caused by random genetic drift. Here we demon...
Data
Evolved strains used for the different experiments. For experiments in Figs 3, 4 and 5, a subset of the isolated auxotrophic and prototrophic strains was chosen, which represented different auxotrophic profiles, thus enabling an analysis of diverse auxotrophic phenotypes that evolved during the course of the experiment. Furthermore, in case of the...
Data
Cumulative distribution of amino acid auxotrophies in all evolved auxotrophs. Shown is the relative frequency with which certain auxotrophies have been detected in all auxotrophic genotypes isolated from (A) the AA regime and (B) the non-AA regime. NA indicates cases that could not be attributed to a specific amino acid auxotrophy. (PDF)
Data
A subset of mutations cause auxotrophy in evolved genotypes. Shown is the maximum optical density (OD) the ancestral genotype (green bar), evolved auxotrophs (red bars), and reconstructed mutants (hatched bars) reached over the course of 24 hours of growth in unsupplemented minimal medium. Asterisks indicate significant differences (one sample t-te...
Data
Non-synonymous mutations identified in the genomes of derived genotypes and their predicted impact on protein functioning. The effect of mutations in coding regions on the functioning of the corresponding protein was predicted using the PROVEAN algorithm [35]. Gene names and their functional assignment are based on Ecocyc [75]. Strain identity code...
Data
Growth kinetic parameters of the ancestor as well as of cognate pairs of auxotrophic and prototrophic strains that evolved in the AA-regime. (A) Maximum growth rate (μmax h-1), (B) duration of the lag phase (h), and (C) duration of the growth phase (h) of the evolutionary ancestor (Anc) as well as the derived auxotrophic (AT) and prototrophic (PT)...
Data
Strains used in this study. Abbreviations: Ara+/- = ability to use arabinose as a carbon source present/ absent, WT = wild type. (PDF)
Data
Genotypic and phenotypic characteristics of sequenced auxotrophic and prototrophic genotypes. The genomic features are also illustrated in Fig 5. Strain identity code: X-Y-Z where X refers to a particular population (1–8), Y refers to the regime, i.e. AA = amino acid, or NA = no amino acid, and Z refers to the phenotype, i.e. either AT = auxotrophi...
Article
Full-text available
Bacterial communities are taxonomically highly diverse, yet the mechanisms that maintain this diversity remain poorly understood. We hypothesized that an obligate and mutual exchange of metabolites, as is very common among bacterial cells, could stabilize different genotypes within microbial communities. To test this, we developed a cellular automa...
Data
Table of state variables and parameters. (PDF)
Data
UML of CELL-ABC representing the order of the main simulation processes. Diagram of the basic processes and procedures of CELL-ABC model. (TIF)
Data
Simulated genotype fractions at different grid dimensions and durations of simulation runs. Fractions of simulated genotypes after (A) 100 simulation steps using grids of different dimensions (n = 15) or (B) on a grid with the dimensions 100x100 grid cells after simulations of a different duration (n = 15). Both parameters were varied to identify t...
Data
Population dynamics in environments with amino acid supplementation. Repeated simulations (n = 100) are plotted for varying benefit-to-cost ratios (BCR) and degrees of amino acid diffusion (bold line: mean, shaded ribbon: standard deviation). All simulations start with a random distribution of all genotypes and undergo a specific dynamic alternatio...
Data
Laboratory experiments. (PDF)
Data
Varying initial fraction of cross-feeding genotypes. Repeated simulations (n = 200) are plotted for varying initial fractions (5% to 95%) of cross-feeding genotypes (i.e. CF1 and CF2) in the community. Simulations were run for low (A and C) and high (B and D) diffusion conditions, both in the absence (A and B) and presence (C and D) of an environme...
Data
Experimentally determined growth parameters of all six genotypes. A Monod kinetic was fitted to the growth of all genotypes. Based on this, the growth parameters (A) Vmax and (B) KM were determined for wild type (WT), the overproducer (Δmdh, OP), the arginine auxotroph (ΔargH, AUX 1), the leucine auxotroph (ΔleuB, AUX 2), as well as the two cross-f...
Article
Full-text available
Metabolism is essential to organismal life, because it provides energy and building block metabolites. Even though it is known that the biosynthesis of metabolites consumes a significant proportion of the resources available to a cell, the factors that determine their production costs remain less well understood. In this context, it is especially u...
Article
Full-text available
Metabolic cross-feeding interactions are ubiquitous in natural microbial communities. However, it remains generally unclear whether the production and exchange of metabolites incurs fitness costs to the producing cells and if so, which ecological mechanisms can facilitate a cooperative exchange of metabolites among unrelated individuals. We hypothe...
Article
Full-text available
Microorganisms frequently engage in reciprocal cross-feeding interactions, in which two or more bacterial strains exchange essential metabolites. Benefits stemming from losing the biosynthetic capabilities to produce certain metabolites likely drive the emergence of these metabolic interdependencies. By using nanotubes, bacteria can effectively exc...
Article
Bacteria of the genus Lysobacter are considered to be facultative predators that use a feeding strategy similar to myxobacteria. Experimental data supporting this assumption, however, is scarce. Therefore, the predatory activity of three Lysobacter species was tested in the 'prey spot plate assay' and in the 'lawn predation assay', which are common...
Article
Full-text available
Evolutionary adaptations for the exploitation of nutritionally challenging or toxic host plants represent a major force driving the diversification of phytophagous insects. Although symbiotic bacteria are known to have essential nutritional roles for insects, examples of radiations into novel ecological niches following the acquisition of specific...
Article
Full-text available
The evolution of cooperation is an intriguing puzzle in evolutionary biology. Several examples have been described where individual microbial cells cooperate by secreting products that are beneficial for the whole community, but reduce the fitness of the producing cells. The spatial distribution within the community provides a solution that can exp...
Article
Many bacterial lineages lack seemingly essential metabolic genes. Previous work suggested selective benefits could drive the loss of biosynthetic functions from bacterial genomes when the corresponding metabolites are sufficiently available in the environment. However, the factors that govern this 'genome streamlining' remain poorly understood. Her...
Article
Full-text available
Bacteria frequently exchange metabolites by diffusion through the extracellular environment, yet it remains generally unclear whether bacteria can also use cell–cell connections to directly exchange nutrients. Here we address this question by engineering cross-feeding interactions within and between Acinetobacter baylyi and Escherichia coli, in whi...
Article
Full-text available
Microorganisms frequently engage in reciprocal cross-feeding interactions , in which two or more bacterial strains exchange essential metabolites. Benefits stemming from losing the biosynthetic capabilities to produce certain metabolites likely drive the emergence of these metabolic interdependencies. By using nanotubes, bacteria can effectively ex...
Article
Motivation: Genome-scale metabolic network reconstructions have been established as a powerful tool for the prediction of cellular phenotypes and metabolic capabilities of organisms. In recent years, the number of network reconstructions has been constantly increasing, mostly because of the availability of novel (semi-)automated procedures, which e...
Article
Full-text available
Leaf-cutting ants (LCAs) are dominant herbivores of the Neotropics, as well as economically important pests. Their foraging ecology and patterns/mechanisms of food selection have received considerable attention. Recently, it has been documented that LCAs exhibit a delayed rejection of previously accepted food plants following treatment with a fungi...
Article
Bacteria that have adapted to nutrient-rich, stable environments are typically characterized by reduced genomes. The loss of biosynthetic genes frequently renders these lineages auxotroph, hinging their survival on an environmental uptake of certain metabolites. The evolutionary forces that drive this genome degradation, however, remain elusive. Ou...
Article
Full-text available
Cross-feeding interactions, in which bacterial cells exchange costly metabolites to the benefit of both interacting partners, are very common in the microbial world. However, it generally remains unclear what maintains this type of interaction in the presence of non-cooperating types. We investigate this problem using synthetic cross-feeding intera...
Article
Full-text available
Jasmonate-mediated regulation of VOC emission has been extensively investigated in higher plants, however, only little is known about VOC production and its regulation in ferns. Here, we investigate whether the emission of VOCs from bracken fern Pteridium aquilinum is triggered by herbivory and if so - whether it is regulated by the octadecanoid si...
Article
Symbiotic bacteria often play an essential nutritional role for insects, thereby allowing them to exploit novel food sources and expand into otherwise inaccessible ecological niches. Although many insects are inhabited by complex microbial communities, most studies on insect mutualists so far have focused on single endosymbionts and their interacti...
Article
Full-text available
Efficient and inexpensive methods are required for the high-throughput quantification of amino acids in physiological fluids or microbial cell cultures. Here we develop an array of Escherichia coli biosensors to sensitively quantify eleven different amino acids. By using online databases, genes involved in amino acid biosynthesis were identified th...
Data
Development of GFP-fluorescence of the tryptophan biosensor cultivated in various concentrations of tryptophan. Mean fluorescence emission of eight replicates is given as relative fluorescence units (RFU) after 12 h (triangles), 18 h (circles), and 24 h (squares) of growth. (TIF)
Data
Time-dependent growth of the eleven biosensors in the presence of the focal amino acid. Biosensor growth was determined as culture turbidity (OD600 nm) in minimal medium supplemented with the focal amino acid (3 mM). Mean values (lines) of eight replicates (squares) are given. (TIF)
Article
Full-text available
Stochastic phenotype switching - or bet hedging - is a pervasive feature of living systems and common in bacteria that experience fluctuating (unpredictable) environmental conditions. Under such conditions, the capacity to generate variable offspring spreads the risk of being maladapted in the present environment, against offspring likely to have s...
Article
Full-text available
Leaf-cutting ants (LCAs) are polyphagous, yet highly selective herbivores. The factors that govern their selection of food plants, however, remain poorly understood. We hypothesized that the induction of anti-herbivore defences by attacked food plants, which are toxic to either ants or their mutualistic fungus, should significantly affect the ants'...
Article
Full-text available
To maximize fitness, plants need to perceive changes in their light environment and adjust their physiological responses accordingly. Whether and how such changes also affect the regulation of their defense responses against herbivores remains largely unclear. We addressed this issue by studying the secretion of extrafloral nectar (EFN) in lima bea...
Conference Paper
Background/Question/Methods Bet hedging stochastic switching between phenotypic states is a canonical example of an evolutionary adaptation that facilitates persistence in the face of fluctuating environmental conditions. While bet hedging is found in organisms ranging from bacteria to humans, direct evidence for an adaptive origin of this behaviou...
Article
Full-text available
Nectar is a rich source of sugars that serves the attraction of pollinators (floral nectar) or predatory arthropods (extrafloral nectar). We just begin to understand the similarities and differences that underlie the secretory control of these two important types of plant secretions. Jasmonates are phytohormones, which are well documented to be inv...
Article
Full-text available
Plants produce nectar in their flowers as a reward for their pollinators and most of our crops depend on insect pollination, but little is known on the physiological control of nectar secretion. Jasmonates are well-known for their effects on senescence, the development and opening of flowers and on plant defences such as extrafloral nectar. Their r...
Conference Paper
Full-text available
Metabolic engineering aims to improve the production of desired biochemicals and proteins in organisms and therefore, plays a central role in Biotechnology. However, the design of overproducing strains is not straightforward due to the complexity of metabolic and regulatory networks. Thus, theoretical tools supporting the design of such strains hav...
Article
Full-text available
Bet hedging-stochastic switching between phenotypic states-is a canonical example of an evolutionary adaptation that facilitates persistence in the face of fluctuating environmental conditions. Although bet hedging is found in organisms ranging from bacteria to humans, direct evidence for an adaptive origin of this behaviour is lacking. Here we rep...
Article
Full-text available
Many plants respond to herbivory with an increased production of extrafloral nectar (EFN) and/or volatile organic compounds (VOCs) to attract predatory arthropods as an indirect defensive strategy. In this study, we tested whether these two indirect defences fit the optimal defence hypothesis (ODH), which predicts the within-plant allocation of ant...
Article
Full-text available
Lima bean (Phaseolus lunatus) features two indirect anti-herbivore defenses-emission of volatile organic compounds (VOCs) and secretion of extrafloral nectar (EFN)-which are both inducible upon herbivore damage. In a previous field study, Lima bean benefited from the simultaneous induction of the two defenses, yet it remained unclear whether both h...
Data
Arthropod taxa trapped on the experimental tendrils with sticky traps .