scholarly journals A New C-Type Lectin Similar to the Human Immunoreceptor DC-SIGN Mediates Symbiont Acquisition by a Marine Nematode

2006 ◽  
Vol 72 (4) ◽  
pp. 2950-2956 ◽  
Author(s):  
Silvia Bulgheresi ◽  
Irma Schabussova ◽  
Tie Chen ◽  
Nicholas P. Mullin ◽  
Rick M. Maizels ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Marine Nematode ◽  
Mannose Binding Protein ◽  
Mannose Binding ◽  
Marine Symbiosis ◽  
Microbe Interactions ◽  
Sulfur Oxidizing ◽  
Host Microbe Interactions ◽  
Symbiont Acquisition

ABSTRACT Although thiotrophic symbioses have been intensively studied for the last three decades, nothing is known about the molecular mechanisms of symbiont acquisition. We used the symbiosis between the marine nematode Laxus oneistus and sulfur-oxidizing bacteria to study this process. In this association a monolayer of symbionts covers the whole cuticle of the nematode, except its anterior-most region. Here, we identify a novel Ca2+-dependent mannose-specific lectin that was exclusively secreted onto the posterior, bacterium-associated region of L. oneistus cuticle. A recombinant form of this lectin induced symbiont aggregation in seawater and was able to compete with the native lectin for symbiont binding in vivo. Surprisingly, the carbohydrate recognition domain of this mannose-binding protein was similar both structurally and functionally to a human dendritic cell-specific immunoreceptor. Our results provide a molecular link between bacterial symbionts and host-secreted mucus in a marine symbiosis and suggest conservation in the mechanisms of host-microbe interactions throughout the animal kingdom.

scholarly journals In vitro cell and tissue models for studying host–microbe interactions: a review

2013 ◽  
Vol 109 (S2) ◽  
pp. S27-S34 ◽  
Author(s):  
Miriam Bermudez-Brito ◽  
Julio Plaza-Díaz ◽  
Luis Fontana ◽  
Sergio Muñoz-Quezada ◽  
Angel Gil
Keyword(s):  
Epithelial Cells ◽  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Experimental Models ◽  
Dynamic Interactions ◽  
Basolateral Side ◽  
Microbe Interactions ◽  
Host Microbe Interactions

Ideally, cell models should resemble the in vivo conditions; however, in most in vitro experimental models, epithelial cells are cultivated as monolayers, in which the establishment of functional epithelial features is not achieved. To overcome this problem, co-culture experiments with probiotics, dendritic cells and intestinal epithelial cells and three-dimensional models attempt to reconcile the complex and dynamic interactions that exist in vivo between the intestinal epithelium and bacteria on the luminal side and between the epithelium and the underlying immune system on the basolateral side. Additional models include tissue explants, bioreactors and organoids. The present review details the in vitro models used to study host–microbe interactions and explores the new tools that may help in understanding the molecular mechanisms of these interactions.

scholarly journals Horizontal acquisition followed by expansion and diversification of toxin-related genes in deep-sea bivalve symbionts

2019 ◽  
Author(s):  
Lizbeth Sayavedra ◽  
Rebecca Ansorge ◽  
Maxim Rubin-Blum ◽  
Nikolaus Leisch ◽  
Nicole Dubilier ◽  
...  
Keyword(s):  
Deep Sea ◽  
Molecular Mechanisms ◽  
Secretion Systems ◽  
Heterogeneous Distribution ◽  
Adaptive Selection ◽  
Evolutionary Origins ◽  
Microbe Interactions ◽  
Sulfur Oxidizing ◽  
Animal Hosts ◽  
Host Microbe Interactions

AbstractDeep-sea bathymodioline mussels gain their nutrition from intracellular bacterial symbionts. Their sulfur-oxidizing (SOX) symbionts were recently shown to encode abundant toxin-related genes (TRGs) in their genomes, which may play a role in beneficial host-microbe interactions. Here, we compared TRGs in the genomes of SOX symbionts from 10 bathymodioline mussel and two sponge species to better understand their potential functions and evolutionary origins. Despite the close phylogenetic relatedness of these symbionts, the number and classes of encoded toxins varied greatly between host species. One of the TRG classes, YDs, has experienced gene expansions multiple times, suggesting that these genes are under adaptive selection. Some symbiont genomes contained secretion systems, which can play a role in host-microbe interactions. Both TRGs and secretion systems had a heterogeneous distribution, suggesting that these closely related bacteria have acquired different molecular mechanisms for interacting with the same family of animal hosts, possibly through convergent evolution.

scholarly journals Polymers in the gut compress the colonic mucus hydrogel

2016 ◽  
Vol 113 (26) ◽  
pp. 7041-7046 ◽  
Author(s):  
Sujit S. Datta ◽  
Asher Preska Steinberg ◽  
Rustem F. Ismagilov
Keyword(s):  
Thermodynamic Model ◽  
Ex Vivo ◽  
Polymer Concentration ◽  
Dietary Fibers ◽  
Physical Damage ◽  
Gut Microbes ◽  
Specific Pathogen ◽  
Microbe Interactions ◽  
Host Microbe Interactions

Colonic mucus is a key biological hydrogel that protects the gut from infection and physical damage and mediates host–microbe interactions and drug delivery. However, little is known about how its structure is influenced by materials it comes into contact with regularly. For example, the gut abounds in polymers such as dietary fibers or administered therapeutics, yet whether such polymers interact with the mucus hydrogel, and if so, how, remains unclear. Although several biological processes have been identified as potential regulators of mucus structure, the polymeric composition of the gut environment has been ignored. Here, we demonstrate that gut polymers do in fact regulate mucus hydrogel structure, and that polymer–mucus interactions can be described using a thermodynamic model based on Flory–Huggins solution theory. We found that both dietary and therapeutic polymers dramatically compressed murine colonic mucus ex vivo and in vivo. This behavior depended strongly on both polymer concentration and molecular weight, in agreement with the predictions of our thermodynamic model. Moreover, exposure to polymer-rich luminal fluid from germ-free mice strongly compressed the mucus hydrogel, whereas exposure to luminal fluid from specific-pathogen-free mice—whose microbiota degrade gut polymers—did not; this suggests that gut microbes modulate mucus structure by degrading polymers. These findings highlight the role of mucus as a responsive biomaterial, and reveal a mechanism of mucus restructuring that must be integrated into the design and interpretation of studies involving therapeutic polymers, dietary fibers, and fiber-degrading gut microbes.

scholarly journals Social interaction-induced activation of RNA splicing in the amygdala of microbiome-deficient mice

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Roman M Stilling ◽  
Gerard M Moloney ◽  
Feargal J Ryan ◽  
Alan E Hoban ◽  
Thomaz FS Bastiaanssen ◽  
...  
Keyword(s):  
Social Interaction ◽  
Social Behaviour ◽  
Rna Splicing ◽  
Molecular Mechanisms ◽  
Autism Spectrum ◽  
Gene Expression Response ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Expression Response ◽  
Multiple Species

Social behaviour is regulated by activity of host-associated microbiota across multiple species. However, the molecular mechanisms mediating this relationship remain elusive. We therefore determined the dynamic, stimulus-dependent transcriptional regulation of germ-free (GF) and GF mice colonised post weaning (exGF) in the amygdala, a brain region critically involved in regulating social interaction. In GF mice the dynamic response seen in controls was attenuated and replaced by a marked increase in expression of splicing factors and alternative exon usage in GF mice upon stimulation, which was even more pronounced in exGF mice. In conclusion, we demonstrate a molecular basis for how the host microbiome is crucial for a normal behavioural response during social interaction. Our data further suggest that social behaviour is correlated with the gene-expression response in the amygdala, established during neurodevelopment as a result of host-microbe interactions. Our findings may help toward understanding neurodevelopmental events leading to social behaviour dysregulation, such as those found in autism spectrum disorders (ASDs).

scholarly journals Longitudinal In Vivo Assessment of Host-Microbe Interactions in a Murine Model of Pulmonary Aspergillosis

iScience ◽  
2019 ◽  
Vol 20 ◽  
pp. 184-194 ◽  
Author(s):  
Shweta Saini ◽  
Jennifer Poelmans ◽  
Hannelie Korf ◽  
James L. Dooley ◽  
Sayuan Liang ◽  
...  
Keyword(s):  
Murine Model ◽  
Pulmonary Aspergillosis ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
In Vivo Assessment

scholarly journals Identification of Erwinia amylovora Genes Induced during Infection of Immature Pear Tissue

2005 ◽  
Vol 187 (23) ◽  
pp. 8088-8103 ◽  
Author(s):  
Youfu Zhao ◽  
Sara E. Blumer ◽  
George W. Sundin
Keyword(s):  
Pseudomonas Syringae ◽  
Erwinia Amylovora ◽  
Sequence Similarity ◽  
Type Ii Secretion ◽  
Knockout Mutant ◽  
Technology System ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Blight Disease

ABSTRACT The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In this study, we used a modified in vivo expression technology system to identify E. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. We identified 394 unique pear fruit-induced (pfi) genes on the basis of sequence similarity to known genes and separated them into nine putative function groups including host-microbe interactions (3.8%), stress response (5.3%), regulation (11.9%), cell surface (8.9%), transport (13.5%), mobile elements (1.0%), metabolism (20.3%), nutrient acquisition and synthesis (15.5%), and unknown or hypothetical proteins (19.8%). Known virulence genes, including hrp/hrc components of the type III secretion system, the major effector gene dspE, type II secretion, levansucrase (lsc), and regulators of levansucrase and amylovoran biosynthesis, were upregulated during pear tissue infection. Known virulence factors previously identified in E. (Pectobacterium) carotovora and Pseudomonas syringae were identified for the first time in E. amylovora and included HecA hemagglutinin family adhesion, Peh polygalacturonase, new effector HopPtoCEA, and membrane-bound lytic murein transglycosylase MltEEA. An insertional mutation within hopPtoC EA did not result in reduced virulence; however, an mltE EA knockout mutant was reduced in virulence and growth in immature pears. This study suggests that E. amylovora utilizes a variety of strategies during plant infection and to overcome the stressful and poor nutritional environment of its plant hosts.

scholarly journals Spatial Analyses of Specialized Metabolites: The Key to Studying Function in Hosts

mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Melissa M. Galey ◽  
Laura M. Sanchez
Keyword(s):  
Analytical Chemistry ◽  
Molecular Mechanisms ◽  
Imaging Mass Spectrometry ◽  
Analytical Techniques ◽  
Spatial Analyses ◽  
Biological Functions ◽  
Specialized Metabolites ◽  
Microbe Interactions ◽  
Host Microbe Interactions

ABSTRACT Microbial communities contribute to a wide variety of biological functions in hosts and have the ability to specifically influence the health of those organisms through production of specialized metabolites. However, the structures or molecular mechanisms related to health or disease in host-microbe interactions represent a knowledge gap. In order to close this gap, we propose that a combinatory approach, pulling from microbiology and analytical chemistry, be considered to investigate these interactions so as to gain a better understanding of the chemistry being produced. We hypothesize that bacteria alter their chemistry in order to survive and induce specific states in their host organisms. Our lab makes use of imaging mass spectrometry and other analytical techniques to study this chemistry in situ , which provides actionable information to test hypotheses.

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