Germ-Free Mice Model for Studying Host–Microbial Interactions

Peatlands store about third of the terrestrial carbon (C) and exert long-term climate cooling. Dominant plant genera in acidic peatlands, Sphagnum mosses, are main contributors to net primary productivity. Through associative relationships with diverse microbial organisms (microbiome), Sphagnum mosses control major biogeochemical processes, namely uptake, storage and potential release of carbon and nitrogen. Climate warming is expected to negatively impact C accumulation in peatlands and alter nutrient cycling, however Sphagnum-dominated peatland resilience to climate warming may depend on Sphagnum-microbiome associations. The ability of the microbiome to rapidly acclimatize to warming may aid Sphagnum exposed to elevated temperatures through host-microbiome acquired thermotolerance. We investigated the role of the microbiome on Sphagnum&#8217;s ability to acclimate to elevated temperatures using a microbiome-transfer approach to test: a) whether the thermal origin of the microbiome influences acclimation of Sphagnum growth and b) if microbial benefits to Sphagnum growth depend on donor Sphagnum species.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Using a full-factorial design, microbiomes were separated from Sphagnum &#8220;donor&#8221; species from four different peatlands across a wide range of thermal environments (11.4-27&#176;C). The microbiomes were transferred onto germ-free &#8220;recipient&#8221; Sphagnum species in the laboratory and exposed to a range of experimental temperatures (8.5 &#8211; 26.5&#176;C) for growth analysis over 4 weeks.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Normalized growth rates were maximized for plants that received a microbiome from a matched &#8220;donor&#8221; and with a similar origin temperature (&#916;Ttreatment-origin: 0.3&#177;0.9&#176;C [&#177;standard error], p = 0.73). For non-matched &#8220;donor-recipient&#8221; Sphagnum pairs, &#916;Ttreatment-origin was slightly negative with -4.1&#177;2.1&#176;C (p = 0.06). The largest growth rate of the &#8220;recipient&#8221; was measured when grown with a microbiome from a matching &#8220;donor&#8221; Sphagnum species and was 252% and 48% larger than the maximum growth rate of the germ-free Sphagnum and the non-matched &#8220;donor-recipient&#8221; Sphagnum pairs, respectively.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Our results suggest that the composition of the Sphagnum microbiome plays a critical role in host plant temperature acclimation. We found that microbially-provided benefits to the host plant were most pronounced when: 1) the thermal origin of the microbiome is similar to experimental temperatures, and 2) when donor and recipient Sphagnum species are the same. Together, these results suggest that Sphagnum temperature acclimation can be modulated, in part, by microbial interactions and may potentially play a role in peatland resilience to climate warming.

Download Full-text

Host-microbial interactions in the lactational period using antibiotic depleted specific pathogen free mice model

American Journal of Obstetrics and Gynecology ◽

10.1016/j.ajog.2021.11.518 ◽

2022 ◽

Vol 226 (1) ◽

pp. S308-S309

Author(s):

Adetola F. Louis-Jacques ◽

Sarah Sniffen ◽

Shaheda Urmi ◽

Maureen Groer ◽

Dominick J. Lemas

Keyword(s):

Microbial Interactions ◽

Specific Pathogen Free ◽

Mice Model ◽

Specific Pathogen

Download Full-text

In vivo imaging and genetic analysis link bacterial motility and symbiosis in the zebrafish gut

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0702386104 ◽

2007 ◽

Vol 104 (18) ◽

pp. 7622-7627 ◽

Cited By ~ 103

Author(s):

John F. Rawls ◽

Michael A. Mahowald ◽

Andrew L. Goodman ◽

Chad M. Trent ◽

Jeffrey I. Gordon

Keyword(s):

Immune Responses ◽

Innate Immune ◽

Microbial Interactions ◽

Microbial Consortia ◽

Innate Immune Responses ◽

Germ Free ◽

Evolutionarily Conserved ◽

Bacterial Genes ◽

The Impact

Complex microbial communities reside within the intestines of humans and other vertebrates. Remarkably little is known about how these microbial consortia are established in various locations within the gut, how members of these consortia behave within their dynamic ecosystems, or what microbial factors mediate mutually beneficial host–microbial interactions. Using a gnotobiotic zebrafish–Pseudomonas aeruginosa model, we show that the transparency of this vertebrate species, coupled with methods for raising these animals under germ-free conditions can be used to monitor microbial movement and localization within the intestine in vivo and in real time. Germ-free zebrafish colonized with isogenic P. aeruginosa strains containing deletions of genes related to motility and pathogenesis revealed that loss of flagellar function results in attenuation of evolutionarily conserved host innate immune responses but not conserved nutrient responses. These results demonstrate the utility of gnotobiotic zebrafish in defining the behavior and localization of bacteria within the living vertebrate gut, identifying bacterial genes that affect these processes, and assessing the impact of these genes on host–microbial interactions.

Download Full-text

Melatonin regulates the neurotransmitter secretion disorder induced by caffeine through the gut-brain axis in zebrafish (Danio rerio)

10.21203/rs.2.19122/v2 ◽

2020 ◽

Author(s):

Qiannan Peng ◽

Zeng Zhang ◽

Dongxue Huo ◽

Shuaiming Jiang ◽

Chenchen Ma ◽

...

Keyword(s):

Microbial Interactions ◽

Metagenomic Sequencing ◽

Metabolic Pathway Analysis ◽

Zebrafish Model ◽

Germ Free ◽

Neurotransmitter Secretion ◽

Validation Experiment ◽

Experiment Validation ◽

Functional Features ◽

Regulatory Effects

Abstract Background: Melatonin has been widely used as a "probiotic agent" capable of producing strong neurotransmitter secretion regulatory effects. The probiotics related researches also provide the evidence of microbial interactions with the gut-brain axis for mental health. In the present study, a zebrafish neural hyperactivity model was established using caffeine induction, and the regulation and mechanism of melatonin and probiotic on zebrafish neurotransmitter secretion disorder were explored. To further address the challenge that if the gut microbes play an essential role in the regulation of neurotransmitter secretion disorder via a process that involves melatonin, the Germ-free (GF) zebrafish model was used to verify the hypothesis. Results: Disorders of brain neurotransmitter secretion caused by caffeine, including that of dopamine (DA), γ-aminobutyric acid (γ-GABA), and 5-hydroxytryptamine (5-HT), were improved after interference treatment with melatonin or the probiotic. Metagenomic sequencing demonstrated that the melatonin-treated zebrafish gradually restored their normal intestinal microbial structure, while probiotic supplementation may restructure a new microbiome. Additionally, supplementation with melatonin significantly regulated intestinal microbial functional features, which indicated the gut microbiota plays the key role in the function of melatonin. Based on this activity, a Germ-free zebrafish model was applied to verified our hypothesis in the following validation experiment. Validation experiment results revealed that the effect on the zebrafish in the GF group could not achieve that on the zebrafish in the melatonin group after adding the same dose of melatonin, and subsequent real-time PCR and metabolic pathway analysis confirmed the conclusion. Meanwhile, the content of acetic acid and propionic acid in the gut of not-germ-free zebrafish decreased after caffeine induction and increased significantly after melatonin treatment. However, no acetic or propionic acids were found, detected, changed as there are germ-free zebrafish. Conclusions: In the present research, we identified the potential mechanism of melatonin regulation of neurotransmitter secretion disorder through the gut-brain axis, laying a foundation for exploring the prevention and treatment of some neuropsychiatric disorders by improving the intestinal microbiota.

Download Full-text

A peek in the micro-sized world: a review of design principles, engineering tools, and applications of engineered microbial community

Biochemical Society Transactions ◽

10.1042/bst20190172 ◽

2020 ◽

Vol 48 (2) ◽

pp. 399-409

Author(s):

Baizhen Gao ◽

Rushant Sabnis ◽

Tommaso Costantini ◽

Robert Jinkerson ◽

Qing Sun

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Environmental Remediation ◽

Real Life ◽

Design Principles ◽

Microbial Interactions ◽

Potential Applications ◽

New Gene ◽

Global Biogeochemical Cycles ◽

Synthetic Microbial Communities

Microbial communities drive diverse processes that impact nearly everything on this planet, from global biogeochemical cycles to human health. Harnessing the power of these microorganisms could provide solutions to many of the challenges that face society. However, naturally occurring microbial communities are not optimized for anthropogenic use. An emerging area of research is focusing on engineering synthetic microbial communities to carry out predefined functions. Microbial community engineers are applying design principles like top-down and bottom-up approaches to create synthetic microbial communities having a myriad of real-life applications in health care, disease prevention, and environmental remediation. Multiple genetic engineering tools and delivery approaches can be used to ‘knock-in' new gene functions into microbial communities. A systematic study of the microbial interactions, community assembling principles, and engineering tools are necessary for us to understand the microbial community and to better utilize them. Continued analysis and effort are required to further the current and potential applications of synthetic microbial communities.

Download Full-text