1
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Lo WS, Sommer RJ, Han Z. Microbiota succession influences nematode physiology in a beetle microcosm ecosystem. Nat Commun 2024; 15:5137. [PMID: 38879542 PMCID: PMC11180206 DOI: 10.1038/s41467-024-49513-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 06/07/2024] [Indexed: 06/19/2024] Open
Abstract
Unravelling the multifaceted and bidirectional interactions between microbiota and host physiology represents a major scientific challenge. Here, we utilise the nematode model, Pristionchus pacificus, coupled to a laboratory-simulated decay process of its insect host, to mimic natural microbiota succession and investigate associated tripartite interactions. Metagenomics reveal that during initial decay stages, the population of vitamin B-producing bacteria diminishes, potentially due to a preferential selection by nematodes. As decay progresses to nutrient-depleted stages, bacteria with smaller genomes producing less nutrients become more prevalent. Lipid utilisation and dauer formation, representing key nematode survival strategies, are influenced by microbiota changes. Additionally, horizontally acquired cellulases extend the nematodes' reproductive phase due to more efficient foraging. Lastly, the expressions of Pristionchus species-specific genes are more responsive to natural microbiota compared to conserved genes, suggesting their importance in the organisms' adaptation to its ecological niche. In summary, we show the importance of microbial successions and their reciprocal interaction with nematodes for insect decay in semi-artificial ecosystems.
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Affiliation(s)
- Wen-Sui Lo
- Institute of Future Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, 72076, Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, 72076, Germany.
| | - Ziduan Han
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, 72076, Germany.
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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2
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Ding SS, Fox JL, Gordus A, Joshi A, Liao JC, Scholz M. Fantastic beasts and how to study them: rethinking experimental animal behavior. J Exp Biol 2024; 227:jeb247003. [PMID: 38372042 PMCID: PMC10911175 DOI: 10.1242/jeb.247003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Humans have been trying to understand animal behavior at least since recorded history. Recent rapid development of new technologies has allowed us to make significant progress in understanding the physiological and molecular mechanisms underlying behavior, a key goal of neuroethology. However, there is a tradeoff when studying animal behavior and its underlying biological mechanisms: common behavior protocols in the laboratory are designed to be replicable and controlled, but they often fail to encompass the variability and breadth of natural behavior. This Commentary proposes a framework of 10 key questions that aim to guide researchers in incorporating a rich natural context into their experimental design or in choosing a new animal study system. The 10 questions cover overarching experimental considerations that can provide a template for interspecies comparisons, enable us to develop studies in new model organisms and unlock new experiments in our quest to understand behavior.
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Affiliation(s)
- Siyu Serena Ding
- Max Planck Institute of Animal Behavior, 78464 Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
| | - Jessica L. Fox
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Andrew Gordus
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Abhilasha Joshi
- Departments of Physiology and Psychiatry, University of California, San Francisco, CA 94158, USA
| | - James C. Liao
- Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesar, 53175 Bonn, Germany
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3
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Kang WK, Florman JT, Araya A, Fox BW, Thackeray A, Schroeder FC, Walhout AJM, Alkema MJ. Vitamin B 12 produced by gut bacteria modulates cholinergic signalling. Nat Cell Biol 2024; 26:72-85. [PMID: 38168768 DOI: 10.1038/s41556-023-01299-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/26/2023] [Indexed: 01/05/2024]
Abstract
A growing body of evidence indicates that gut microbiota influence brain function and behaviour. However, the molecular basis of how gut bacteria modulate host nervous system function is largely unknown. Here we show that vitamin B12-producing bacteria that colonize the intestine can modulate excitatory cholinergic signalling and behaviour in the host Caenorhabditis elegans. Here we demonstrate that vitamin B12 reduces cholinergic signalling in the nervous system through rewiring of the methionine (Met)/S-adenosylmethionine cycle in the intestine. We identify a conserved metabolic crosstalk between the methionine/S-adenosylmethionine cycle and the choline-oxidation pathway. In addition, we show that metabolic rewiring of these pathways by vitamin B12 reduces cholinergic signalling by limiting the availability of free choline required by neurons to synthesize acetylcholine. Our study reveals a gut-brain communication pathway by which enteric bacteria modulate host behaviour and may affect neurological health.
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Affiliation(s)
- Woo Kyu Kang
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Jeremy T Florman
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Antonia Araya
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Bennett W Fox
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Andrea Thackeray
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Albertha J M Walhout
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Mark J Alkema
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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4
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Kalirad A, Sommer RJ. Spatial and temporal heterogeneity alter the cost of plasticity in Pristionchus pacificus. PLoS Comput Biol 2024; 20:e1011823. [PMID: 38289972 PMCID: PMC10857712 DOI: 10.1371/journal.pcbi.1011823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 02/09/2024] [Accepted: 01/11/2024] [Indexed: 02/01/2024] Open
Abstract
Phenotypic plasticity, the ability of a single genotype to produce distinct phenotypes under different environmental conditions, has become a leading concept in ecology and evolutionary biology, with the most extreme examples being the formation of alternative phenotypes (polyphenisms). However, several aspects associated with phenotypic plasticity remain controversial, such as the existence of associated costs. While already predicted by some of the pioneers of plasticity research, i.e. Schmalhausen and Bradshaw, experimental and theoretical approaches have provided limited support for the costs of plasticity. In experimental studies, one common restriction is the measurement of all relevant parameters over long time periods. Similarly, theoretical studies rarely use modelling approaches that incorporate specific experimentally-derived fitness parameters. Therefore, the existence of the costs of plasticity remains disputed. Here, we provide an integrative approach to understand the cost of adaptive plasticity and its ecological ramifications, by combining laboratory data from the nematode plasticity model system Pristionchus pacificus with a stage-structured population model. Taking advantage of measurements of two isogenic strains grown on two distinct diets, we illustrate how spatial and temporal heterogeneity with regard to the distribution of resources on a metapopulation can alter the outcome of the competition and alleviate the realized cost of plasticity.
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Affiliation(s)
- Ata Kalirad
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Ralf J. Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
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5
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Zhou J, Qin W, Lu X, Yang Y, Stahl D, Jiao N, Zhou J, Liu J, Tu Q. The diversity and ecological significance of microbial traits potentially involved in B 12 biosynthesis in the global ocean. MLIFE 2023; 2:416-427. [PMID: 38818271 PMCID: PMC10989127 DOI: 10.1002/mlf2.12095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/21/2023] [Accepted: 10/04/2023] [Indexed: 06/01/2024]
Abstract
Cobalamin (B12), an essential nutrient and growth cofactor for many living organisms on Earth, can be fully synthesized only by selected prokaryotes in nature. Therefore, microbial communities related to B12 biosynthesis could serve as an example subsystem to disentangle the underlying ecological mechanisms balancing the function and taxonomic make-up of complex functional assemblages. By anchoring microbial traits potentially involved in B12 biosynthesis, we depict the biogeographic patterns of B12 biosynthesis genes and the taxa harboring them in the global ocean, despite the limitations of detecting de novo B12 synthesizers via metagenomes alone. Both the taxonomic and functional composition of B12 biosynthesis genes were strongly shaped by depth, differentiating the epipelagic zones from the mesopelagic layers. Functional genes related to B12 biosynthesis were relatively stably distributed across different oceans, but the taxa harboring them varied considerably, showing clear functional redundancy among microbial systems. Microbial taxa carrying B12 biosynthesis genes in the surface water were influenced by environmental factors such as temperature, oxygen, and nitrate. However, the composition of functional genes was only weakly associated with these environmental factors. Null model analyses demonstrated that determinism governed the variations in B12 biosynthesis genes, whereas a higher degree of stochasticity was associated with taxonomic variations. Significant associations were observed between the chlorophyll a concentration and B12 biosynthesis, confirming its importance in primary production in the global ocean. The results of this study reveal an essential ecological mechanism governing the assembly of microbes in nature: the environment selects for function rather than taxonomy; functional redundancy underlies stochastic community assembly.
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Affiliation(s)
- Jiayin Zhou
- Institute of Marine Science and TechnologyShandong UniversityQingdaoChina
- Joint Lab for Ocean Research and Education at Dalhousie UniversityShandong University and Xiamen UniversityQingdaoChina
| | - Wei Qin
- School of Biological SciencesUniversity of OklahomaNormanOklahomaUSA
| | - Xinda Lu
- Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
- Present address:
DermBiont Inc.BostonMassachusettsUSA
| | - Yunfeng Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of EnvironmentTsinghua UniversityBeijingChina
| | - David Stahl
- Department of Civil and Environmental EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Nianzhi Jiao
- Institute of Marine Science and TechnologyShandong UniversityQingdaoChina
- Institute of Marine Microbes and EcospheresXiamen UniversityXiamenChina
| | - Jizhong Zhou
- School of Biological SciencesUniversity of OklahomaNormanOklahomaUSA
- Earth and Environmental Sciences, Lawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- Institute for Environmental Genomics, University of OklahomaNormanOklahomaUSA
- School of Civil Engineering and Environmental Sciences, University of OklahomaNormanOklahomaUSA
- School of Computer Sciences, University of OklahomaNormanOklahomaUSA
| | - Jihua Liu
- Institute of Marine Science and TechnologyShandong UniversityQingdaoChina
- Joint Lab for Ocean Research and Education at Dalhousie UniversityShandong University and Xiamen UniversityQingdaoChina
| | - Qichao Tu
- Institute of Marine Science and TechnologyShandong UniversityQingdaoChina
- Joint Lab for Ocean Research and Education at Dalhousie UniversityShandong University and Xiamen UniversityQingdaoChina
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6
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Hiramatsu F, Lightfoot JW. Kin-recognition and predation shape collective behaviors in the cannibalistic nematode Pristionchus pacificus. PLoS Genet 2023; 19:e1011056. [PMID: 38096160 PMCID: PMC10721034 DOI: 10.1371/journal.pgen.1011056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/08/2023] [Indexed: 12/17/2023] Open
Abstract
Kin-recognition is observed across diverse species forming an important behavioral adaptation influencing organismal interactions. In many species, the molecular mechanisms involved are difficult to characterize, but in the nematode Pristionchus pacificus molecular components regulating its kin-recognition system have been identified. These determine its predatory behaviors towards other con-specifics which prevents the killing and cannibalization of kin. Importantly, their impact on other interactions including collective behaviors is unknown. Here, we explored a high altitude adapted clade of this species which aggregates abundantly under laboratory conditions, to investigate the influence of the kin-recognition system on their group behaviours. By utilizing pairwise aggregation assays between distinct strains of P. pacificus with differing degrees of genetic relatedness, we observe aggregation between kin but not distantly related strains. In assays between distantly related strains, the aggregation ratio is frequently reduced. Furthermore, abolishing predation behaviors through CRISPR/Cas9 induced mutations in Ppa-nhr-40 result in rival strains successfully aggregating together. Finally, as Caenorhabditis elegans are found naturally occurring with P. pacificus, we also explored aggregation events between these species. Here, aggregates were dominated by P. pacificus with the presence of only a small number of predators proving sufficient to disrupt C. elegans aggregation dynamics. Thus, aggregating strains of P. pacificus preferentially group with kin, revealing competition and nepotism as previously unknown components influencing collective behaviors in nematodes.
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Affiliation(s)
- Fumie Hiramatsu
- Max Planck Research Group Genetics of Behavior, Max Planck Institute for Neurobiology of Behavior–caesar, Bonn, Germany
- International Max Planck Research School for Brain and Behavior, Bonn, Germany
| | - James W. Lightfoot
- Max Planck Research Group Genetics of Behavior, Max Planck Institute for Neurobiology of Behavior–caesar, Bonn, Germany
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7
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Athanasouli M, Akduman N, Röseler W, Theam P, Rödelsperger C. Thousands of Pristionchus pacificus orphan genes were integrated into developmental networks that respond to diverse environmental microbiota. PLoS Genet 2023; 19:e1010832. [PMID: 37399201 DOI: 10.1371/journal.pgen.1010832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/15/2023] [Indexed: 07/05/2023] Open
Abstract
Adaptation of organisms to environmental change may be facilitated by the creation of new genes. New genes without homologs in other lineages are known as taxonomically-restricted orphan genes and may result from divergence or de novo formation. Previously, we have extensively characterized the evolution and origin of such orphan genes in the nematode model organism Pristionchus pacificus. Here, we employ large-scale transcriptomics to establish potential functional associations and to measure the degree of transcriptional plasticity among orphan genes. Specifically, we analyzed 24 RNA-seq samples from adult P. pacificus worms raised on 24 different monoxenic bacterial cultures. Based on coexpression analysis, we identified 28 large modules that harbor 3,727 diplogastrid-specific orphan genes and that respond dynamically to different bacteria. These coexpression modules have distinct regulatory architecture and also exhibit differential expression patterns across development suggesting a link between bacterial response networks and development. Phylostratigraphy revealed a considerably high number of family- and even species-specific orphan genes in certain coexpression modules. This suggests that new genes are not attached randomly to existing cellular networks and that integration can happen very fast. Integrative analysis of protein domains, gene expression and ortholog data facilitated the assignments of biological labels for 22 coexpression modules with one of the largest, fast-evolving module being associated with spermatogenesis. In summary, this work presents the first functional annotation for thousands of P. pacificus orphan genes and reveals insights into their integration into environmentally responsive gene networks.
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Affiliation(s)
- Marina Athanasouli
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Nermin Akduman
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Waltraud Röseler
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Penghieng Theam
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
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8
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Shi S, Cao M, Zhang Y, Fan X, Liu S, Chen J, Zhou J. Enhanced hydrolysis/acidogenesis and potential mechanism in thermal-alkali-biofilm synergistic pretreatment of high-solid and low-organic-content sludge. BIORESOURCE TECHNOLOGY 2023; 378:128988. [PMID: 37001699 DOI: 10.1016/j.biortech.2023.128988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/25/2023] [Accepted: 03/28/2023] [Indexed: 06/19/2023]
Abstract
Improving the anaerobic digestion (AD) of high-solid and low-organic-content sludge is imperative for sustainable waste activated sludge (WAS) management. Here, a thermal-alkali-biofilm pretreatment (TAB) was established to treat high-solid and low-organic-content sludge and compared with thermal and thermal-alkali methods. The results showed that TAB drastically improved WAS reduction, hydrolysis/acidogenesis efficiency, and biochemical methane potential. TAB possessed the lowest sludge particle size and the highest surface charge due to the stimulated proteolysis and WAS solubilization, supported by the protease activity test and secondary substrate identification. In addition, the biofilm assistance noticeably accelerated the elimination of autochthonous bacteria in WAS (e.g., Proteobacteria) and facilitated the enrichment of specialized fermentative microorganisms (e.g., Firmicutes) along with relevant functional genes, lying molecular foundation for the enhanced hydrolysis/acidogenesis in TAB. These findings could expand the application of biofilm in the AD of WAS and provide new insight into the pretreatment strategy of high-solid and low-organic-content sludge.
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Affiliation(s)
- Shuohui Shi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Meng Cao
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Ying Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Xing Fan
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Shihu Liu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jiahao Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jian Zhou
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
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9
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Dardiry M, Piskobulu V, Kalirad A, Sommer RJ. Experimental and theoretical support for costs of plasticity and phenotype in a nematode cannibalistic trait. Evol Lett 2023; 7:48-57. [PMID: 37065436 PMCID: PMC10091500 DOI: 10.1093/evlett/qrac001] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 11/01/2022] [Accepted: 12/06/2022] [Indexed: 02/04/2023] Open
Abstract
Abstract
Developmental plasticity is the ability of a genotype to express multiple phenotypes under different environmental conditions and has been shown to facilitate the evolution of novel traits. However, while the associated cost of plasticity, i.e., the loss in fitness due to the ability to express plasticity in response to environmental change, and the cost of phenotype, i.e., the loss of fitness due to expressing a fixed phenotype across environments, have been theoretically predicted, empirically such costs remain poorly documented and little understood. Here, we use a plasticity model system, hermaphroditic nematode Pristionchus pacificus, to experimentally measure these costs in wild isolates under controlled laboratory conditions. P. pacificus can develop either a bacterial feeding or predatory mouth morph in response to different external stimuli, with natural variation of mouth-morph ratios between strains. We first demonstrated the cost of phenotype by analyzing fecundity and developmental speed in relation to mouth morphs across the P. pacificus phylogenetic tree. Then, we exposed P. pacificus strains to two distinct microbial diets that induce strain-specific mouth-form ratios. Our results indicate that the plastic strain does shoulder a cost of plasticity, i.e., the diet-induced predatory mouth morph is associated with reduced fecundity and slower developmental speed. In contrast, the non-plastic strain suffers from the cost of phenotype since its phenotype does not change to match the unfavorable bacterial diet but shows increased fitness and higher developmental speed on the favorable diet. Furthermore, using a stage-structured population model based on empirically derived life history parameters, we show how population structure can alleviate the cost of plasticity in P. pacificus. The results of the model illustrate the extent to which the costs associated with plasticity and its effect on competition depend on ecological factors. This study provides support for costs of plasticity and phenotype based on empirical and modeling approaches.
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Affiliation(s)
- Mohannad Dardiry
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen , Tübingen , Germany
| | - Veysi Piskobulu
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen , Tübingen , Germany
| | - Ata Kalirad
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen , Tübingen , Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology Tübingen , Tübingen , Germany
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10
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The emerging pathogen Enterocytozoon hepatopenaei drives a degenerative cyclic pattern in the hepatopancreas microbiome of the shrimp (Penaeus vannamei). Sci Rep 2022; 12:14766. [PMID: 36042348 PMCID: PMC9427843 DOI: 10.1038/s41598-022-19127-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 08/24/2022] [Indexed: 11/19/2022] Open
Abstract
The microsporidian Enterocytozoon hepatopenaei (EHP) is an emerging pathogen that causes substantial economic losses in shrimp (Penaeus spp.) aquaculture worldwide. To prevent diseases in shrimp, the manipulation of the gut microbiota has been suggested. However, prior knowledge of the host-microbiome is necessary. We assessed the modulation of the microbiome (bacteria/fungi) and its predicted functions over the course of disease progression in shrimp experimentally challenged with EHP for 30 days using high throughput 16S rRNA and ITS amplicon sequencing. Infection grade was assessed for the first time by quantitative digital histopathology. According to the infection intensity, three disease-stages (early/developmental/late) were registered. During the early-stage, EHP was not consistently detected, and a high diversity of potentially beneficial microorganisms related to nutrient assimilation were found. In the development-stage, most of the shrimp start to register a high infection intensity related to a decrease in beneficial microorganisms and an increase in opportunistic/pathogenic fungi. During late-stage, animals displayed different infection intensities, showed a displacement of beneficial microorganisms by opportunistic/pathogenic bacteria and fungi related to pathogen infection processes and depletion of energetic reserves. The degenerative cyclic pattern of EHP infection and its effects on beneficial microorganisms and beneficial functions of the shrimp hepatopancreas microbiome are discussed.
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McDonagh A, Crew J, van der Linden AM. Dietary vitamin B12 regulates chemosensory receptor gene expression via the MEF2 transcription factor in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2022; 12:6580222. [PMID: 35512190 PMCID: PMC9157118 DOI: 10.1093/g3journal/jkac107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 04/24/2022] [Indexed: 02/02/2023]
Abstract
Dynamic changes in chemoreceptor gene expression levels in sensory neurons are one strategy that an animal can use to modify their responses to dietary changes. However, the mechanisms underlying diet-dependent modulation of chemosensory gene expression are unclear. Here, we show that the expression of the srh-234 chemoreceptor gene localized in a single ADL sensory neuron type of Caenorhabditis elegans is downregulated when animals are fed a Comamonas aquatica bacterial diet, but not on an Escherichia coli diet. Remarkably, this diet-modulated effect on srh-234 expression is dependent on the micronutrient vitamin B12 endogenously produced by Comamonas aq. bacteria. Excess propionate and genetic perturbations in the canonical and shunt propionate breakdown pathways are able to override the repressive effects of vitamin B12 on srh-234 expression. The vitamin B12-mediated regulation of srh-234 expression levels in ADL requires the MEF-2 MADS domain transcription factor, providing a potential mechanism by which dietary vitamin B12 may transcriptionally tune individual chemoreceptor genes in a single sensory neuron type, which in turn may change animal responses to biologically relevant chemicals in their diet.
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Affiliation(s)
- Aja McDonagh
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Jeannette Crew
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Alexander M van der Linden
- Department of Biology, University of Nevada, Reno, NV 89557, USA,Corresponding author: Department of Biology, University of Nevada, Reno, NV 89557, USA.
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12
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Synergistic interaction of gut microbiota enhances the growth of nematode through neuroendocrine signaling. Curr Biol 2022; 32:2037-2050.e4. [PMID: 35397201 DOI: 10.1016/j.cub.2022.03.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/23/2022] [Accepted: 03/18/2022] [Indexed: 01/21/2023]
Abstract
Animals are associated with a diverse bacterial community that impacts host physiology. It is well known that nutrients and enzymes synthesized by bacteria largely expand host metabolic capacity. Bacteria also impact a wide range of animal physiology that solely depends on host genetics through direct interaction. However, studying the synergistic effects of the bacterial community remains challenging due to its complexity. The omnivorous nematode Pristionchus pacificus has limited digestive efficiency on bacteria. Therefore, we established a bacterial collection that represents the natural gut microbiota that are resistant to digestion. Using this collection, we show that the bacterium Lysinibacillus xylanilyticus by itself provides limited nutritional value, but in combination with Escherichia coli, it significantly promotes life-history traits of P. pacificus by regulating the neuroendocrine peptide in sensory neurons. This gut-to-brain communication depends on undigested L. xylanilyticus providing Pristionchus nematodes a specific fitness advantage to compete with nematodes that rupture bacteria efficiently. Using RNA-seq and CRISPR-induced mutants, we show that 1-h exposure to L. xylanilyticus is sufficient to stimulate the expression of daf-7-type TGF-β signaling ligands, which induce a global transcriptome change. In addition, several effects of L. xylanilyticus depend on TGF-β signaling, including olfaction, body size regulation, and a switch of energy allocation from lipid storage to reproduction. Our results reveal the beneficial effects of a gut bacterium to modify life-history traits and maximize nematode survival in natural habitats.
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13
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Lev I, Zimmer M. Predator–prey interactions: Strategic biting. Curr Biol 2022; 32:R367-R370. [DOI: 10.1016/j.cub.2022.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Li G, Zheng X, Zhu Y, Long Y, Xia X. Bacillus symbiont drives alterations in intestinal microbiota and circulating metabolites of lepidopteran host. Environ Microbiol 2022; 24:4049-4064. [PMID: 35191580 DOI: 10.1111/1462-2920.15934] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/01/2021] [Accepted: 02/08/2022] [Indexed: 12/01/2022]
Abstract
The symbiotic association between bacterial symbionts and insect hosts is a complicated process that is not completely understood. Herein, we used a silkworm model to study the association between symbiotic Bacillus and lepidopteran insect by investigating the changes in intestinal microbiota and hemolymph circulating metabolites of silkworm after symbiotic Bacillus subtilis treatment. Results showed that B. subtilis can generate a variety of primary and secondary metabolites, such as B vitamins and antimicrobial compounds, to provide micronutrients and enhance the pathogen resistance of their insect host. Shifts in the relative abundance of Enterococcus, Brevibacterium, Buttiauxella, Pseudomonas, Brevundimonas, and Limnobacter had significant correlations with the concentrations of differential metabolites (e.g., phospholipids and certain amino acids) in insect hemolymph. The antimicrobial compounds secreted by B. subtilis were the primary driving force for the reconstruction of intestinal microbiota. Meanwhile, the altered levels of circulating metabolites in multiple metabolic pathways were potential an adaptive mechanism of insect hosts in response to the shifts of intestinal microbiota. Our findings provided concrete evidence that bacterial intestinal symbiont can alter the physiological state of insects and highlighted the importance of the compositional alterations of intestinal microbiota as a source of variation in circulating metabolites of insect hosts. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Guannan Li
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass, Southwest University, Chongqing, 400716, China.,Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
| | - Xi Zheng
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass, Southwest University, Chongqing, 400716, China
| | - Yong Zhu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass, Southwest University, Chongqing, 400716, China
| | - Yaohang Long
- Key Laboratory of Biology and Medical Engineering, Immune Cells and Antibody Engineering Research Center of Guizhou Province, School of Biology and Engineering, Guizhou Medical University, Guiyang, 550025, Guizhou Province, P.R. China
| | - Xuejuan Xia
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
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15
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Han Z, Sieriebriennikov B, Susoy V, Lo WS, Igreja C, Dong C, Berasategui A, Witte H, Sommer RJ. Horizontally acquired cellulases assist the expansion of dietary range in Pristionchus nematodes. Mol Biol Evol 2022; 39:6493351. [PMID: 34978575 PMCID: PMC8826503 DOI: 10.1093/molbev/msab370] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Horizontal gene transfer (HGT) enables the acquisition of novel traits via non-Mendelian inheritance of genetic material. HGT plays a prominent role in the evolution of prokaryotes, whereas in animals, HGT is rare and its functional significance is often uncertain. Here, we investigate horizontally acquired cellulase genes in the free-living nematode model organism Pristionchus pacificus. We show that these cellulase genes 1) are likely of eukaryotic origin, 2) are expressed, 3) have protein products that are secreted and functional, and 4) result in endo-cellulase activity. Using CRISPR/Cas9, we generated an octuple cellulase mutant, which lacks all eight cellulase genes and cellulase activity altogether. Nonetheless, this cellulase-null mutant is viable and therefore allows a detailed analysis of a gene family that was horizontally acquired. We show that the octuple cellulase mutant has associated fitness costs with reduced fecundity and slower developmental speed. Furthermore, by using various Escherichia coli K-12 strains as a model for cellulosic biofilms, we demonstrate that cellulases facilitate the procurement of nutrients from bacterial biofilms. Together, our analysis of cellulases in Pristionchus provides comprehensive evidence from biochemistry, genetics, and phylogeny, which supports the integration of horizontally acquired genes into the complex life history strategy of this soil nematode.
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Affiliation(s)
- Ziduan Han
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
| | | | - Vladislav Susoy
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
| | - Wen-Sui Lo
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
| | - Catia Igreja
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
| | - Chuanfu Dong
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
| | | | - Hanh Witte
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
| | - Ralf J Sommer
- Max-Planck Institute for Developmental Biology, Tuebingen, 72076, Germany
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16
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Renahan T, Sommer RJ. Nematode Interactions on Beetle Hosts Indicate a Role of Mouth-Form Plasticity in Resource Competition. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.752695] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Competition is rampant across kingdoms, arising over potential mates, food resources, and space availability. When faced with opponents, phenotypic plasticity proffers organisms indispensable advantageous strategies to outcompete rivals. This tactic is especially crucial on decaying insect hosts as myriad microbes and numerous nematodes struggle to establish thriving populations and ensure resource availability for future generations. Scarab beetles and their associated nematode symbionts on La Réunion Island have provided exceptional systems to study complicated cross-phylum interactions in soil, and recently we have identified a previously unexplored beetle host, Gymnogaster bupthalma, to be reliably co-infested with diplogastrids Pristionchus mayeri and Acrostichus spp. These nematodes maintain the capacity to plastically respond to environmental conditions by developing disparate mouth forms, a strict bacterial-feeding morph or an omnivorous morph that enables predation on other nematodes. In addition, under stressful settings these worms can enter an arrested development stage called dauer, non-feeding dispersal larvae that resume development into reproducing adults when conditions improve. By investigating this beetle-nematode system in a natural context, we uncovered a novel Pristionchus strategy, wherein dauer dispersal from the carcass is gradual and a reproducing population is sustained. Remarkably, usually preferential-bacterial morph P. mayeri develop as predators in populations dense with competitors.
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17
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Lightfoot JW, Dardiry M, Kalirad A, Giaimo S, Eberhardt G, Witte H, Wilecki M, Rödelsperger C, Traulsen A, Sommer RJ. Sex or cannibalism: Polyphenism and kin recognition control social action strategies in nematodes. SCIENCE ADVANCES 2021; 7:7/35/eabg8042. [PMID: 34433565 PMCID: PMC8386922 DOI: 10.1126/sciadv.abg8042] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 07/01/2021] [Indexed: 05/10/2023]
Abstract
Resource polyphenisms, where single genotypes produce alternative feeding strategies in response to changing environments, are thought to be facilitators of evolutionary novelty. However, understanding the interplay between environment, morphology, and behavior and its significance is complex. We explore a radiation of Pristionchus nematodes with discrete polyphenic mouth forms and associated microbivorous versus cannibalistic traits. Notably, comparing 29 Pristionchus species reveals that reproductive mode strongly correlates with mouth-form plasticity. Male-female species exhibit the microbivorous morph and avoid parent-offspring conflict as indicated by genetic hybrids. In contrast, hermaphroditic species display cannibalistic morphs encouraging competition. Testing predation between 36 co-occurring strains of the hermaphrodite P. pacificus showed that killing inversely correlates with genomic relatedness. These empirical data together with theory reveal that polyphenism (plasticity), kin recognition, and relatedness are three major factors that shape cannibalistic behaviors. Thus, developmental plasticity influences cooperative versus competitive social action strategies in diverse animals.
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Affiliation(s)
- James W Lightfoot
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
- Max Planck Research Group Self-Recognition and Cannibalism, Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
| | - Mohannad Dardiry
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
- Department of Genetics, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt
| | - Ata Kalirad
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
| | - Stefano Giaimo
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Gabi Eberhardt
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
| | - Hanh Witte
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
| | - Martin Wilecki
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
| | - Christian Rödelsperger
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany
| | - Arne Traulsen
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Ralf J Sommer
- Max Planck Institute for Developmental Biology, Max-Planck Ring 9, 72076 Tübingen, Germany.
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18
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Sun S, Roedelsperger C, Sommer RJ. Single worm transcriptomics identifies a developmental core network of oscillating genes with deep conservation across nematodes. Genome Res 2021; 31:1590-1601. [PMID: 34301622 PMCID: PMC8415380 DOI: 10.1101/gr.275303.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 07/14/2021] [Indexed: 12/05/2022]
Abstract
High-resolution spatial and temporal maps of gene expression have facilitated a comprehensive understanding of animal development and evolution. In nematodes, the small body size represented a major challenge for such studies, but recent advancements have helped overcome this limitation. Here, we have implemented single worm transcriptomics (SWT) in the nematode model organism Pristionchus pacificus to provide a high-resolution map of the developmental transcriptome. We selected 38 time points from hatching of the J2 larvae to young adults to perform transcriptome analysis over 60 h of postembryonic development. A mean sequencing depth of 4.5 million read pairs allowed the detection of more than 23,135 (80%) of all genes. Nearly 3000 (10%) genes showed oscillatory expression with discrete expression levels, phases, and amplitudes. Gene age analysis revealed an overrepresentation of ancient gene classes among oscillating genes, and around one-third of them have 1:1 orthologs in C. elegans. One important gene family overrepresented among oscillating genes is collagens. Several of these collagen genes are regulated by the developmental switch gene eud-1, indicating a potential function in the regulation of mouth-form plasticity, a key developmental process in this facultative predatory nematode. Together, our analysis provides (1) an updated protocol for SWT in nematodes that is applicable to many microscopic species, (2) a 1- to 2-h high-resolution catalog of P. pacificus gene expression throughout postembryonic development, and (3) a comparative analysis of oscillatory gene expression between the two model organisms P. pacificus and C. elegans and associated evolutionary dynamics.
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Affiliation(s)
- Shuai Sun
- Max Planck Institute for Developmental Biology
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19
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Abstract
Cobalamin (vitamin B12; VB12) is an indispensable nutrient for all living entities in the Earth’s biosphere and plays a vital role in both natural and host environments. Currently in the metagenomic era, gene families of interest are extracted and analyzed based on functional profiles by searching shotgun metagenomes against public databases. However, critical issues exist in applying public databases for specific processes such as VB12 biosynthesis pathways. We developed a curated functional gene database termed VB12Path for accurate metagenomic profiling of VB12 biosynthesis gene families of microbial communities in complex environments. VB12Path contains a total of 60 VB12 synthesis gene families, 287,731 sequences, and 21,154 homology groups, and it aims to provide accurate functional and taxonomic profiles of VB12 synthesis pathways for shotgun metagenomes and minimize false-positive assignments. VB12Path was applied to characterize cobalamin biosynthesis gene families in human intestines and marine environments. The results demonstrated that ocean and human intestine had dramatically different VB12 synthesis processes and that gene families belonging to salvage and remodeling pathway dominated human intestine but were lowest in the ocean ecosystem. VB12Path is expected to be a useful tool to study cobalamin biosynthesis processes via shotgun metagenome sequencing in both environmental and human microbiome research. IMPORTANCE Vitamin B12 (VB12) is an indispensable nutrient for all living entities in the world but can only be synthesized by a small subset of prokaryotes. Therefore, this small subset of prokaryotes controls ecosystem stability and host health to some extent. However, critical accuracy and comprehensiveness issues exist in applying public databases to profile VB12 synthetic gene families and taxonomic groups in complex metagenomes. In this study, we developed a curated functional gene database termed VB12Path for accurate metagenomic profiling of VB12 communities in complex environments. VB12Path is expected to serve as a valuable tool to uncover the hidden microbial communities producing this precious nutrient on Earth.
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20
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Li M, Li T, Zhou M, Li M, Zhao Y, Xu J, Hu F, Li H. Caenorhabditis elegans Extracts Stimulate IAA Biosynthesis in Arthrobacter pascens ZZ21 via the Indole-3-pyruvic Acid Pathway. Microorganisms 2021; 9:microorganisms9050970. [PMID: 33946196 PMCID: PMC8146544 DOI: 10.3390/microorganisms9050970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/24/2021] [Accepted: 04/28/2021] [Indexed: 11/16/2022] Open
Abstract
Inter-organismal metabolites play important roles in regulating organism behavior and the communication between organisms. Nematodes, the most abundant animals on earth, are crucial participants in soil ecosystems through their interactions with microbes. For example, bacterial-feeding nematodes increase the activity of indole-3-acetic acid (IAA)-producing bacteria and the IAA content in soil. However, the way in which these nematodes interact with bacteria and affect IAA biosynthesis is not well understood. Here, using the model nematode Caenorhabditis elegans and the plant-beneficial bacterium Arthrobacter pascens ZZ21, we examined the effects of nematode excretions or extracts on bacterial IAA biosynthesis. To explore the underlying regulatory mechanism in more detail, we performed transcriptome sequencing and metabolomic analysis. Our findings suggest that C. elegans extracts promote IAA biosynthesis in A. pascens ZZ21 by increasing the expression of genes and the abundance of intermediates involved in the indole-3-pyruvic acid (IPyA) pathway. C. elegans extracts also significantly influenced biosynthetic and metabolic activity in A. pascens ZZ21. Treatment with C. elegans extracts promoted pyruvate metabolism, the citrate cycle (TCA) cycle and the production of some TCA-cycle-related amino acids and inhibited oxidative phosphorylation, which induced the accumulation of reduced nicotinamide adenine dinucleotide (NADH). We propose that the extracts altered the metabolism of A. pascens ZZ21 to help the bacteria resist stress caused by their predator. Our findings indicate that bacterial-feeding nematodes mediate the interaction between nematodes and bacteria via their extracts, providing insights into the ecological function of C. elegans in soil.
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Affiliation(s)
- Mengsha Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
- College of Science & Technology, Ningbo University, Cixi 315300, China
| | - Teng Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
| | - Ming Zhou
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
| | - Mengdi Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
| | - Yexin Zhao
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
| | - Jingjing Xu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
| | - Feng Hu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210014, China
| | - Huixin Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; (M.L.); (T.L.); (M.Z.); (M.L.); (Y.Z.); (J.X.); (F.H.)
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210014, China
- Correspondence: ; Tel.: +86-025-84395374
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21
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Renahan T, Lo WS, Werner MS, Rochat J, Herrmann M, Sommer RJ. Nematode biphasic 'boom and bust' dynamics are dependent on host bacterial load while linking dauer and mouth-form polyphenisms. Environ Microbiol 2021; 23:5102-5113. [PMID: 33587771 DOI: 10.1111/1462-2920.15438] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 01/06/2023]
Abstract
Cross-kingdom interactions involve dynamic processes that shape terrestrial ecosystems and represent striking examples of co-evolution. The multifaceted relationships of entomopathogenic nematodes with their insect hosts and symbiotic bacteria are well-studied cases of co-evolution and pathogenicity. In contrast, microbial interactions in soil after the natural death of insects and other invertebrates are minimally understood. In particular, the turnover and succession of nematodes and bacteria during insect decay have not been well documented - although it represents a rich ecological niche with multiple species interactions. Here, we utilize developmentally plastic nematode Pristionchus pacificus and its associated scarab beetles as models. On La Réunion Island, we collected rhinoceros beetle Oryctes borbonicus, induced death, and placed carcasses in cages both on the island and in a mock-natural environment in the laboratory controlling for high spatial and temporal resolution. Investigating nematode population density and dispersal dynamics, we were able to connect two imperative plasticities, dauer and mouth form. We observed a biphasic 'boom and bust' dispersal dynamic of dauer larvae that corresponds to bacterial load on carcasses but not bacterial type. Strikingly, all post-dauer adults have the predatory mouth form, demonstrating novel intricate interactions on decaying insect hosts. Thus, ecologically relevant survival strategies incorporate critical plastic traits.
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Affiliation(s)
- Tess Renahan
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
| | - Wen-Sui Lo
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
| | - Michael S Werner
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany.,Department of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA
| | - Jacques Rochat
- Micropoda, 2 Rue De l'é'toile du Berger, Residence le Jardin des Épices, La Possession, La Réunion, 97419, France
| | - Matthias Herrmann
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
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22
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Han Z, Lo WS, Lightfoot JW, Witte H, Sun S, Sommer RJ. Improving Transgenesis Efficiency and CRISPR-Associated Tools Through Codon Optimization and Native Intron Addition in Pristionchus Nematodes. Genetics 2020; 216:947-956. [PMID: 33060138 PMCID: PMC7768246 DOI: 10.1534/genetics.120.303785] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
A lack of appropriate molecular tools is one obstacle that prevents in-depth mechanistic studies in many organisms. Transgenesis, clustered regularly interspaced short palindromic repeats (CRISPR)-associated engineering, and related tools are fundamental in the modern life sciences, but their applications are still limited to a few model organisms. In the phylum Nematoda, transgenesis can only be performed in a handful of species other than Caenorhabditis elegans, and additionally, other species suffer from significantly lower transgenesis efficiencies. We hypothesized that this may in part be due to incompatibilities of transgenes in the recipient organisms. Therefore, we investigated the genomic features of 10 nematode species from three of the major clades representing all different lifestyles. We found that these species show drastically different codon usage bias and intron composition. With these findings, we used the species Pristionchus pacificus as a proof of concept for codon optimization and native intron addition. Indeed, we were able to significantly improve transgenesis efficiency, a principle that may be usable in other nematode species. In addition, with the improved transgenes, we developed a fluorescent co-injection marker in P. pacificus for the detection of CRISPR-edited individuals, which helps considerably to reduce associated time and costs.
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Affiliation(s)
- Ziduan Han
- Max Planck Institute for Developmental Biology, Tuebingen 72076, Germany
| | - Wen-Sui Lo
- Max Planck Institute for Developmental Biology, Tuebingen 72076, Germany
| | - James W Lightfoot
- Max Planck Institute for Developmental Biology, Tuebingen 72076, Germany
| | - Hanh Witte
- Max Planck Institute for Developmental Biology, Tuebingen 72076, Germany
| | - Shuai Sun
- Max Planck Institute for Developmental Biology, Tuebingen 72076, Germany
| | - Ralf J Sommer
- Max Planck Institute for Developmental Biology, Tuebingen 72076, Germany
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23
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Athanasouli M, Witte H, Weiler C, Loschko T, Eberhardt G, Sommer RJ, Rödelsperger C. Comparative genomics and community curation further improve gene annotations in the nematode Pristionchus pacificus. BMC Genomics 2020; 21:708. [PMID: 33045985 PMCID: PMC7552371 DOI: 10.1186/s12864-020-07100-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/23/2020] [Indexed: 02/07/2023] Open
Abstract
Background Nematode model organisms such as Caenorhabditis elegans and Pristionchus pacificus are powerful systems for studying the evolution of gene function at a mechanistic level. However, the identification of P. pacificus orthologs of candidate genes known from C. elegans is complicated by the discrepancy in the quality of gene annotations, a common problem in nematode and invertebrate genomics. Results Here, we combine comparative genomic screens for suspicious gene models with community-based curation to further improve the quality of gene annotations in P. pacificus. We extend previous curations of one-to-one orthologs to larger gene families and also orphan genes. Cross-species comparisons of protein lengths, screens for atypical domain combinations and species-specific orphan genes resulted in 4311 candidate genes that were subject to community-based curation. Corrections for 2946 gene models were implemented in a new version of the P. pacificus gene annotations. The new set of gene annotations contains 28,896 genes and has a single copy ortholog completeness level of 97.6%. Conclusions Our work demonstrates the effectiveness of comparative genomic screens to identify suspicious gene models and the scalability of community-based approaches to improve the quality of thousands of gene models. Similar community-based approaches can help to improve the quality of gene annotations in other invertebrate species, including parasitic nematodes.
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Affiliation(s)
- Marina Athanasouli
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Hanh Witte
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Christian Weiler
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Tobias Loschko
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Gabi Eberhardt
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076, Tübingen, Germany.
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24
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Quach KT, Chalasani SH. Intraguild predation between Pristionchus pacificus and Caenorhabditis elegans: a complex interaction with the potential for aggressive behaviour. J Neurogenet 2020; 34:404-419. [PMID: 33054476 PMCID: PMC7836027 DOI: 10.1080/01677063.2020.1833004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/20/2020] [Indexed: 12/20/2022]
Abstract
The related nematodes Pristionchus pacificus and Caenorhabditis elegans both eat bacteria for nutrition and are therefore competitors when they exploit the same bacterial resource. In addition to competing with each other, P. pacificus is a predator of C. elegans larval prey. These two relationships together form intraguild predation, which is the killing and sometimes eating of potential competitors. In killing C. elegans, the intraguild predator P. pacificus may achieve dual benefits of immediate nutrition and reduced competition for bacteria. Recent studies of P. pacificus have characterized many aspects of its predatory biting behaviour as well as underlying molecular and genetic mechanisms. However, little has been explored regarding the potentially competitive aspect of P. pacificus biting C. elegans. Moreover, aggression may also be implicated if P. pacificus intentionally bites C. elegans with the goal of reducing competition for bacteria. The aim of this review is to broadly outline how aggression, predation, and intraguild predation relate to each other, as well as how these concepts may be applied to future studies of P. pacificus in its interactions with C. elegans.
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Affiliation(s)
- Kathleen T. Quach
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sreekanth H. Chalasani
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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