scholarly journals A Stenotrophomonas maltophilia Strain Evades a Major Caenorhabditis elegans Defense Pathway

2015 ◽  
Vol 84 (2) ◽  
pp. 524-536 ◽  
Author(s):  
Corin V. White ◽  
Brian J. Darby ◽  
Robert J. Breeden ◽  
Michael A. Herman
Keyword(s):  
Caenorhabditis Elegans ◽  
Stenotrophomonas Maltophilia ◽  
Pathogenic Bacteria ◽  
Pathogen Resistance ◽  
Nosocomial Pathogen ◽  
Content Type ◽  
C Elegans ◽  
Novel Host ◽  
Bacterial Accumulation ◽  
Intestinal Distension

Stenotrophomonas maltophiliais a ubiquitous bacterium and an emerging nosocomial pathogen. This bacterium is resistant to many antibiotics, associated with a number of infections, and a significant health risk, especially for immunocompromised patients. Given thatCaenorhabditis elegansshares many conserved genetic pathways and pathway components with higher organisms, the study of its interaction with bacterial pathogens has biomedical implications.S. maltophiliahas been isolated in association with nematodes from grassland soils, and it is likely thatC. elegansencounters this bacterium in nature. We found that a localS. maltophiliaisolate, JCMS, is more virulent than the otherS. maltophiliaisolates (R551-3 and K279a) tested. JCMS virulence correlates with intestinal distension and bacterial accumulation and requires the bacteria to be alive. Many of the conserved innate immune pathways that serve to protectC. elegansfrom various pathogenic bacteria also play a role in combatingS. maltophiliaJCMS. However,S. maltophiliaJCMS is virulent to normally pathogen-resistant DAF-2/16 insulin-like signaling pathway mutants. Furthermore, several insulin-like signaling effector genes were not significantly differentially expressed betweenS. maltophiliaJCMS and avirulent bacteria (Escherichia coliOP50). Taken together, these findings suggest thatS. maltophiliaJCMS evades the pathogen resistance conferred by the loss of DAF-2/16 pathway components. In summary, we have discovered a novel host-pathogen interaction betweenC. elegansandS. maltophiliaand established a new animal model with which to study the mode of action of this emerging nosocomial pathogen.

scholarly journals Intergenerational Pathogen-Induced Diapause in Caenorhabditis elegans Is Modulated by mir-243

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Carolaing Gabaldón ◽  
Marcela Legüe ◽  
M. Fernanda Palominos ◽  
Lidia Verdugo ◽  
Florence Gutzwiller ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Noncoding Rna ◽  
Pathogenic Bacteria ◽  
Developmental Change ◽  
Differential Expression Analysis ◽  
Phenotypic Analysis ◽  
Content Type ◽  
C Elegans ◽  
Two Generations ◽  
Dauer Formation

ABSTRACT The interaction and communication between bacteria and their hosts modulate many aspects of animal physiology and behavior. Dauer entry as a response to chronic exposure to pathogenic bacteria in Caenorhabditis elegans is an example of a dramatic survival response. This response is dependent on the RNA interference (RNAi) machinery, suggesting the involvement of small RNAs (sRNAs) as effectors. Interestingly, dauer formation occurs after two generations of interaction with two unrelated moderately pathogenic bacteria. Therefore, we sought to discover the identity of C. elegans RNAs involved in pathogen-induced diapause. Using transcriptomics and differential expression analysis of coding and long and small noncoding RNAs, we found that mir-243-3p (the mature form of mir-243) is the only transcript continuously upregulated in animals exposed to both Pseudomonas aeruginosa and Salmonella enterica for two generations. Phenotypic analysis of mutants showed that mir-243 is required for dauer formation under pathogenesis but not under starvation. Moreover, DAF-16, a master regulator of defensive responses in the animal and required for dauer formation was found to be necessary for mir-243 expression. This work highlights the role of a small noncoding RNA in the intergenerational defensive response against pathogenic bacteria and interkingdom communication. IMPORTANCE Persistent infection of the bacterivore nematode C. elegans with bacteria such as P. aeruginosa and S. enterica makes the worm diapause or hibernate. By doing this, the worm closes its mouth, avoiding infection. This response takes two generations to be implemented. In this work, we looked for genes expressed upon infection that could mediate the worm diapause triggered by pathogens. We identify mir-243-3p as the only transcript commonly upregulated when animals feed on P. aeruginosa and S. enterica for two consecutive generations. Moreover, we demonstrate that mir-243-3p is required for pathogen-induced dauer formation, a new function that has not been previously described for this microRNA (miRNA). We also find that the transcriptional activators DAF-16, PQM-1, and CRH-2 are necessary for the expression of mir-243 under pathogenesis. Here we establish a relationship between a small RNA and a developmental change that ensures the survival of a percentage of the progeny.

scholarly journals Spread and Transmission of Bacterial Pathogens in Experimental Populations of the Nematode Caenorhabditis elegans

2014 ◽  
Vol 80 (17) ◽  
pp. 5411-5418 ◽  
Author(s):  
S. Anaid Diaz ◽  
Olivier Restif
Keyword(s):  
Caenorhabditis Elegans ◽  
Pathogenic Bacteria ◽  
Transmission Rate ◽  
Bacterial Species ◽  
Opportunistic Pathogens ◽  
Content Type ◽  
Factors Affecting ◽  
C Elegans ◽  
Series Of Experiments ◽  
Initial Source

ABSTRACTCaenorhabditis elegansis frequently used as a model species for the study of bacterial virulence and innate immunity. In recent years, diverse mechanisms contributing to the nematode's immune response to bacterial infection have been discovered. Yet despite growing interest in the biochemical and molecular basis of nematode-bacterium associations, many questions remain about their ecology. Although recent studies have demonstrated that free-living nematodes could act as vectors of opportunistic pathogens in soil, the extent to which worms may contribute to the persistence and spread of these bacteria has not been quantified. We conducted a series of experiments to test whether colonization of and transmission betweenC. elegansnematodes could enable two opportunistic pathogens (Salmonella entericaandPseudomonas aeruginosa) to spread on agar plates occupied byEscherichia coli. We monitored the transmission ofS. entericaandP. aeruginosafrom single infected nematodes to their progeny and measured bacterial loads both within worms and on the plates. In particular, we analyzed three factors affecting the dynamics of bacteria: (i) initial source of the bacteria, (ii) bacterial species, and (iii) feeding behavior of the host. Results demonstrate that worms increased the spread of bacteria through shedding and transmission. Furthermore, we found that despiteP. aeruginosa's relatively high transmission rate among worms, its pathogenic effects reduced the overall number of worms colonized. This study opens new avenues to understand the role of nematodes in the epidemiology and evolution of pathogenic bacteria in the environment.

scholarly journals Temporal Transcriptomics of Gut Escherichia coli in Caenorhabditis elegans Models of Aging

2021 ◽  
Author(s):  
Joshua D. Brycki ◽  
Jeremy R. Chen See ◽  
Gillian R. Letson ◽  
Cade S. Emlet ◽  
Lavinia V. Unverdorben ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Caenorhabditis Elegans ◽  
Life Span ◽  
Wild Type ◽  
Health Span ◽  
Content Type ◽  
C Elegans ◽  
Evolutionarily Conserved

Previous research has reported effects of the microbiome on health span and life span of Caenorhabditis elegans , including interactions with evolutionarily conserved pathways in humans. We build on this literature by reporting the gene expression of Escherichia coli OP50 in wild-type (N2) and three long-lived mutants of C. elegans .

scholarly journals Complete Genome Sequence of Stenotrophomonas maltophilia Myophage Moby

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Alison Vicary ◽  
Heather Newkirk ◽  
Russell Moreland ◽  
Carlos F. Gonzalez ◽  
Mei Liu ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Stenotrophomonas Maltophilia ◽  
Nosocomial Pathogen ◽  
Protein Coding ◽  
Content Type ◽  
Protein Coding Genes ◽  
Phage T4

Stenotrophomonas maltophilia is a prevalent nosocomial pathogen with multidrug resistance. Here, we describe the complete genome of S. maltophilia myophage Moby, which shares characteristics with Enterobacteria phage T4 and is closely related to Stenotrophomonas phage IME-SM1. Moby has a 159,365-bp genome with 271 predicted protein-coding genes and 24 predicted tRNAs.

scholarly journals Sonic Stimulation and Low Power Microwave Radiation Can Modulate Bacterial Virulence Towards Caenorhabditis elegans

2019 ◽  
Vol 17 (2) ◽  
pp. 150-162
Author(s):  
Priya Patel ◽  
Hiteshi Patel ◽  
Dhara Vekariya ◽  
Chinmayi Joshi ◽  
Pooja Patel ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Microwave Radiation ◽  
Pathogenic Bacteria ◽  
Bacterial Virulence ◽  
Therapeutic Approaches ◽  
Microwave Exposure ◽  
C Elegans ◽  
Sonic Treatment ◽  
Global Threat ◽  
Sound Treatment

<P>Background: In view of the global threat of antimicrobial resistance, novel alternative approaches to deal with infectious bacteria are warranted, in addition to the conventional invasive therapeutic approaches. Objective: This study aimed at investigating whether exposure to sonic stimulation or microwave radiation can affect virulence of pathogenic bacteria toward the model nematode host Caenorhabditis elegans. Methods: Caenorhabditis elegans worms infected with different pathogenic bacteria were subjected to sonic treatment to investigate whether such sound treatment can exert any therapeutic effect on the infected worms. Virulence of microwave exposed bacteria was also assessed using this nematode host. Results: Sound corresponding to 400 Hz, and the divine sound ‘Om’ conferred protective effect on C. elegans in face of bacterial infection, particularly that caused by Serratia marcescens or Staphylococcus aureus. The observed effect seemed to occur due to influence of sound on bacteria, and not on the worm. Additionally, effect of microwave exposure on bacterial virulence was also investigated, wherein microwave exposure could reduce virulence of S. aureus towards C. elegans. Conclusion: Sonic stimulation/ microwave exposure was demonstrated to be capable of modulating bacterial virulence.</P>

scholarly journals Caenorhabditis elegans as a Model System To Assess Candida glabrata, Candida nivariensis, and Candida bracarensis Virulence and Antifungal Efficacy

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Ainara Hernando-Ortiz ◽  
Estibaliz Mateo ◽  
Marcelo Ortega-Riveros ◽  
Iker De-la-Pinta ◽  
Guillermo Quindós ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Candida Glabrata ◽  
Model System ◽  
Antifungal Drugs ◽  
Phenotypic Traits ◽  
Content Type ◽  
C Elegans ◽  
Host Fungus ◽  
Candida Bracarensis ◽  
Candida Nivariensis

ABSTRACT Although Candida albicans remains the major etiological agent of invasive candidiasis, Candida glabrata and other emerging species of Candida are increasingly isolated. This species is the second most prevalent cause of candidiasis in many regions of the world. However, clinical isolates of Candida nivariensis and Candida bracarensis can be misidentified and are underdiagnosed due to phenotypic traits shared with C. glabrata. Little is known about the two cryptic species. Therefore, pathogenesis studies are needed to understand their virulence traits and their susceptibility to antifungal drugs. The susceptibility of Caenorhabditis elegans to different Candida species makes this nematode an excellent model for assessing host-fungus interactions. We evaluated the usefulness of C. elegans as a nonconventional host model to analyze the virulence of C. glabrata, C. nivariensis, and C. bracarensis. The three species caused candidiasis, and the highest virulence of C. glabrata was confirmed. Furthermore, we determined the efficacy of current antifungal drugs against the infection caused by these species in the C. elegans model. Amphotericin B and azoles showed the highest activity against C. glabrata and C. bracarensis infections, while echinocandins were more active for treating those caused by C. nivariensis. C. elegans proved to be a useful model system for assessing the pathogenicity of these closely related species.

scholarly journals Caenorhabditis elegans as an Emerging Model for Virus-Host Interactions

2017 ◽  
Vol 91 (23) ◽  
Author(s):  
Don B. Gammon
Keyword(s):  
Caenorhabditis Elegans ◽  
Virus Infection ◽  
Fungal Pathogens ◽  
Model Organism ◽  
Artificial Infection ◽  
Viral Pathogen ◽  
Content Type ◽  
Host Interactions ◽  
C Elegans ◽  
Infection Models

ABSTRACT Since 1999, Caenorhabditis elegans has been extensively used to study microbe-host interactions due to its simple culture, genetic tractability, and susceptibility to numerous bacterial and fungal pathogens. In contrast, virus studies have been hampered by a lack of convenient virus infection models in nematodes. The recent discovery of a natural viral pathogen of C. elegans and development of diverse artificial infection models are providing new opportunities to explore virus-host interplay in this powerful model organism.

scholarly journals Metagenome-Assembled Draft Genome Sequence of a Novel Microbial Stenotrophomonas maltophilia Strain Isolated from Caenorhabditisremanei Tissue

2017 ◽  
Vol 5 (7) ◽  
Author(s):  
Janna L. Fierst ◽  
Duncan A. Murdock ◽  
Chamali Thanthiriwatte ◽  
John H. Willis ◽  
Patrick C. Phillips
Keyword(s):  
Genome Sequence ◽  
Stenotrophomonas Maltophilia ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Aerobic Bacterium ◽  
Nosocomial Pathogen ◽  
Metagenomic Dna ◽  
Content Type ◽  
Nematode Worm ◽  
Caenorhabditis Remanei

ABSTRACT Stenotrophomonas maltophilia is a Gram-negative aerobic bacterium and emerging nosocomial pathogen. Here, we present a draft genome sequence for an S. maltophilia strain assembled from a metagenomic DNA extract isolated from a laboratory stock of the nematode worm Caenorhabditis remanei.

scholarly journals Identification of a Conserved, Orphan G Protein-Coupled Receptor Required for Efficient Pathogen Clearance in Caenorhabditis elegans

2019 ◽  
Vol 87 (4) ◽  
Author(s):  
Alexandra Anderson ◽  
Yee Lian Chew ◽  
William Schafer ◽  
Rachel McMullan
Keyword(s):  
Caenorhabditis Elegans ◽  
Immune Responses ◽  
G Protein ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled Receptor ◽  
Content Type ◽  
C Elegans ◽  
Host Immune Responses ◽  
Pathogen Clearance ◽  
G Protein Coupled

ABSTRACT G protein-coupled receptors contribute to host defense across the animal kingdom, transducing many signals involved in both vertebrate and invertebrate immune responses. While it has become well established that the nematode worm Caenorhabditis elegans triggers innate immune responses following infection with numerous bacterial, fungal, and viral pathogens, the mechanisms by which C. elegans recognizes these pathogens have remained somewhat more elusive. C. elegans G protein-coupled receptors have been implicated in recognizing pathogen-associated damage and activating downstream host immune responses. Here we identify and characterize a novel G protein-coupled receptor required to regulate the C. elegans response to infection with Microbacterium nematophilum. We show that this receptor, which we designate pathogen clearance-defective receptor 1 (PCDR-1), is required for efficient pathogen clearance following infection. PCDR-1 acts upstream of multiple G proteins, including the C. elegans Gαq ortholog, EGL-30, in rectal epithelial cells to promote pathogen clearance via a novel mechanism.

Take a Walk to the Wild Side of Caenorhabditis elegans-Pathogen Interactions

2021 ◽  
Vol 85 (2) ◽  
Author(s):  
Leah J. Radeke ◽  
Michael A. Herman
Keyword(s):  
Innate Immunity ◽  
Caenorhabditis Elegans ◽  
Recent Work ◽  
Genetic Model ◽  
Model Organism ◽  
Bacterial Pathogen ◽  
Content Type ◽  
Microbiome Composition ◽  
C Elegans ◽  
Functional Studies

SUMMARY Microbiomes form intimate functional associations with their hosts. Much has been learned from correlating changes in microbiome composition to host organismal functions. However, in-depth functional studies require the manipulation of microbiome composition coupled with the precise interrogation of organismal physiology—features available in few host study systems. Caenorhabditis elegans has proven to be an excellent genetic model organism to study innate immunity and, more recently, microbiome interactions. The study of C. elegans-pathogen interactions has provided in depth understanding of innate immune pathways, many of which are conserved in other animals. However, many bacteria were chosen for these studies because of their convenience in the lab setting or their implication in human health rather than their native interactions with C. elegans. In their natural environment, C. elegans feed on a variety of bacteria found in rotting organic matter, such as rotting fruits, flowers, and stems. Recent work has begun to characterize the native microbiome and has identified a common set of bacteria found in the microbiome of C. elegans. While some of these bacteria are beneficial to C. elegans health, others are detrimental, leading to a complex, multifaceted understanding of bacterium-nematode interactions. Current research on nematode-bacterium interactions is focused on these native microbiome components, both their interactions with each other and with C. elegans. We will summarize our knowledge of bacterial pathogen-host interactions in C. elegans, as well as recent work on the native microbiome, and explore the incorporation of these bacterium-nematode interactions into studies of innate immunity and pathogenesis.

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