Salmonella biofilms program innate immunity for persistence in Caenorhabditis elegans

The adaptive in vivo mechanisms underlying the switch in Salmonella enterica lifestyles from the infectious form to a dormant form remain unknown. We employed Caenorhabditis elegans as a heterologous host to understand the temporal dynamics of Salmonella pathogenesis and to identify its lifestyle form in vivo. We discovered that Salmonella exists as sessile aggregates, or in vivo biofilms, in the persistently infected C. elegans gut. In the absence of in vivo biofilms, Salmonella killed the host more rapidly by actively inhibiting innate immune pathways. Regulatory cross-talk between two major Salmonella pathogenicity islands, SPI-1 and SPI-2, was responsible for biofilm-induced changes in host physiology during persistent infection. Thus, biofilm formation is a survival strategy in long-term infections, as prolonging host survival is beneficial for the parasitic lifestyle.

Download Full-text

Caenorhabditis elegans Learning and Memory

Oxford Research Encyclopedia of Neuroscience ◽

10.1093/acrefore/9780190264086.013.282 ◽

2019 ◽

Author(s):

James S.H. Wong ◽

Catharine H. Rankin

Keyword(s):

Carbon Dioxide ◽

Caenorhabditis Elegans ◽

Classical Conditioning ◽

Learning And Memory ◽

Long Term Memory ◽

Context Conditioning ◽

Term Memory ◽

C Elegans

The nematode, Caenorhabditis elegans (C. elegans), is an organism useful for the study of learning and memory at the molecular, cellular, neural circuitry, and behavioral levels. Its genetic tractability, transparency, connectome, and accessibility for in vivo cellular and molecular analyses are a few of the characteristics that make the organism such a powerful system for investigating mechanisms of learning and memory. It is able to learn and remember across many sensory modalities, including mechanosensation, chemosensation, thermosensation, oxygen sensing, and carbon dioxide sensing. C. elegans habituates to mechanosensory stimuli, and shows short-, intermediate-, and long-term memory, and context conditioning for mechanosensory habituation. The organism also displays chemotaxis to various chemicals, such as diacetyl and sodium chloride. This behavior is associated with several forms of learning, including state-dependent learning, classical conditioning, and aversive learning. C. elegans also shows thermotactic learning in which it learns to associate a particular temperature with the presence or absence of food. In addition, both oxygen preference and carbon dioxide avoidance in C. elegans can be altered by experience, indicating that they have memory for the oxygen or carbon dioxide environment they were reared in. Many of the genes found to underlie learning and memory in C. elegans are homologous to genes involved in learning and memory in mammals; two examples are crh-1, which is the C. elegans homolog of the cAMP response element-binding protein (CREB), and glr-1, which encodes an AMPA glutamate receptor subunit. Both of these genes are involved in long-term memory for tap habituation, context conditioning in tap habituation, and chemosensory classical conditioning. C. elegans offers the advantage of having a very small nervous system (302 neurons), thus it is possible to understand what these conserved genes are doing at the level of single identified neurons. As many mechanisms of learning and memory in C. elegans appear to be similar in more complex organisms including humans, research with C. elegans aids our ever-growing understanding of the fundamental mechanisms of learning and memory across the animal kingdom.

Download Full-text

Caenorhabditis elegans as an in vivo Model to Assess Amphetamine Tolerance

Brain Behavior and Evolution ◽

10.1159/000514858 ◽

2021 ◽

pp. 1-9

Author(s):

Dayana Torres Valladares ◽

Sirisha Kudumala ◽

Murad Hossain ◽

Lucia Carvelli

Keyword(s):

Caenorhabditis Elegans ◽

Molecular Mechanisms ◽

Drugs Of Abuse ◽

Genetic Model ◽

In Vivo Model ◽

C Elegans ◽

Hyperactivity Disorder ◽

In Vitro Data

Amphetamine is a potent psychostimulant also used to treat attention deficit/hyperactivity disorder and narcolepsy. In vivo and in vitro data have demonstrated that amphetamine increases the amount of extra synaptic dopamine by both inhibiting reuptake and promoting efflux of dopamine through the dopamine transporter. Previous studies have shown that chronic use of amphetamine causes tolerance to the drug. Thus, since the molecular mechanisms underlying tolerance to amphetamine are still unknown, an animal model to identify the neurochemical mechanisms associated with drug tolerance is greatly needed. Here we took advantage of a unique behavior caused by amphetamine in <i>Caenorhabditis elegans</i> to investigate whether this simple, but powerful, genetic model develops tolerance following repeated exposure to amphetamine. We found that at least 3 treatments with 0.5 mM amphetamine were necessary to see a reduction in the amphetamine-induced behavior and, thus, to promote tolerance. Moreover, we found that, after intervals of 60/90 minutes between treatments, animals were more likely to exhibit tolerance than animals that underwent 10-minute intervals between treatments. Taken together, our results show that <i>C. elegans</i> is a suitable system to study tolerance to drugs of abuse such as amphetamines.

Download Full-text

Transfer and tissue-specific accumulation of components in embryos of Caenorhabditis elegans and dolichura: in vivo analysis with a low-cost signal

Development ◽

10.1242/dev.114.2.317 ◽

1992 ◽

Vol 114 (2) ◽

pp. 317-330 ◽

Cited By ~ 4

Author(s):

O. Bossinger ◽

E. Schierenberg

Keyword(s):

Caenorhabditis Elegans ◽

Low Cost ◽

Free Living ◽

Tissue Specific ◽

C Elegans ◽

Specific Accumulation ◽

In Vivo Analysis

The pattern of autofluorescence in the two free-living namatodes Rhabditis dolichura and Caenorhabditis compared. In C. elegans, during later embryogenesis cells develop a typical bluish autofluorescence as illumination, while in Rh. dolichura a strong already present in the unfertilized egg. Using a new,

Download Full-text

Brevinin-2 Drug Family—New Applied Peptide Candidates Against Methicillin-Resistant Staphylococcus aureus and Their Effects on Lys-7 Expression of Innate Immune Pathway DAF-2/DAF-16 in Caenorhabditis elegans

Applied Sciences ◽

10.3390/app8122627 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2627

Author(s):

Hui Xie ◽

Yonghua Zhan ◽

Xueli Chen ◽

Qi Zeng ◽

Dan Chen ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Survival Rate ◽

Caenorhabditis Elegans ◽

Antimicrobial Peptides ◽

Real Time ◽

Innate Immune ◽

C Elegans ◽

New Drug ◽

Immune Pathway ◽

Innate Immune Pathway

The issue of Staphylococcus aureus (MRSA) developing a resistance to drugs such as methicillin has long been the focus for new drug development. In recent years, antimicrobial peptides, such as small molecular peptides with broad-spectrum antibacterial activity and special antibacterial mechanism, have shown a strong medicinal potential. In particular, the Brevinin-2 family has been shown to have a significant inhibitory effect against gram-positive bacteria (G+). In this study, we researched the influence of MRSA on the behavior and survival rate of nematodes. We established an assay of Caenorhabditis elegans–MRSA antimicrobial peptides to screen for new potent anti-infective peptides against MRSA. From the Brevinin-2 family, 13 peptides that had shown strong effects on G+ were screened for their ability to prolong the lifespan of infected worms. Real-time Polymerase Chain Reaction (PCR) tests were used to evaluate the effect on the innate immune pathway dauer formation defective (DAF)-2/DAF-16 of C. elegans. The assay successfully screened and filtered out four of the 13 peptides that significantly improved the survival rate of MRSA-infected worms. The result of real-time PCR indicated that the mRNA and protein expression levels of lys-7 were consistently upregulated by being treated with four of the Brevinin-2 family. The Brevinin-2 family peptides, including Brevinin-2, Brevinin-2-OA3, Brevinin-2ISb, and Brevinin-2TSa, also played an active role in the DAF-2/DAF-16 pathway in C. elegans. We successfully demonstrated the utility of anti-infective peptides that prolong the survival rate of the MRSA-infected host and discovered the relationship between antibacterial peptides and the innate immune system of C. elegans. We demonstrated the antimicrobial effects of Brevinin-2 family peptides, indicating their potential for use as new drug candidates against MRSA infections.

Download Full-text

Edible Flowers of Tagetes erecta L. as Functional Ingredients: Phenolic Composition, Antioxidant and Protective Effects on Caenorhabditis elegans

Nutrients ◽

10.3390/nu10122002 ◽

2018 ◽

Vol 10 (12) ◽

pp. 2002 ◽

Cited By ~ 7

Author(s):

Cristina Moliner ◽

Lillian Barros ◽

Maria Dias ◽

Víctor López ◽

Elisa Langa ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

In Vivo Model ◽

Tagetes Erecta ◽

Protective Effects ◽

Phenolic Composition ◽

C Elegans ◽

Amyloid Toxicity ◽

Phenolic Profiles ◽

Tagetes Erecta L

Tagetes erecta L. has long been consumed for culinary and medicinal purposes in different countries. The aim of this study was to explore the potential benefits from two cultivars of T. erecta related to its polyphenolic profile as well as antioxidant and anti-aging properties. The phenolic composition was analyzed by LC-DAD-ESI/MSn. Folin-Ciocalteu, DPPH·, and FRAP assays were performed in order to evaluate reducing antiradical properties. The neuroprotective potential was evaluated using the enzymes acetylcholinesterase and monoamine oxidase. Caenorhabditis elegans was used as an in vivo model to assess extract toxicity, antioxidant activity, delayed aging, and reduced β-amyloid toxicity. Both extracts showed similar phenolic profiles and bioactivities. The main polyphenols found were laricitin and its glycosides. No acute toxicity was detected for extracts in the C. elegans model. T. erecta flower extracts showed promising antioxidant and neuroprotective properties in the different tested models. Hence, these results may add some information supporting the possibilities of using these plants as functional foods and/or as nutraceutical ingredients.

Download Full-text

Progressive recruitment of distal MEC-4 channels determines touch response strength in C. elegans

10.1101/587014 ◽

2019 ◽

Cited By ~ 1

Author(s):

S. Katta ◽

A. Sanzeni ◽

A. Das ◽

M. Vergassola ◽

M.B. Goodman

Keyword(s):

Temporal Dynamics ◽

Mechanical Strain ◽

Tissue Mechanics ◽

Mechanical Stimuli ◽

Patch Clamp Recording ◽

Open Probability ◽

C Elegans ◽

Somatosensory Neurons ◽

Touch Response

AbstractTouch deforms, or strains, the skin beyond the immediate point of contact. The spatiotemporal nature of the touch-induced strain fields depend on the mechanical properties of the skin and the tissues below. Somatosensory neurons that sense touch branch out within the skin and rely on a set of mechano-electrical transduction channels distributed within their dendrites to detect mechanical stimuli. Here, we sought to understand how tissue mechanics shape touch-induced mechanical strain across the skin over time and how individual channels located in different regions of the strain field contribute to the overall touch response. We leveraged C. elegans’ touch receptor neurons (TRNs) as a simple model amenable to in vivo whole-cell patch clamp recording and an integrated experimental-computational approach to dissect the mechanisms underlying the spatial and temporal dynamics that we observed. Consistent with the idea that strain is produced at a distance, we show that delivering strong stimuli outside the anatomical extent of the neuron is sufficient to evoke MRCs. The amplitude and kinetics of the MRCs depended on both stimulus displacement and speed. Finally, we found that the main factor responsible for touch sensitivity is the recruitment of progressively more distant channels by stronger stimuli, rather than modulation of channel open probability. This principle may generalize to somatosensory neurons with more complex morphologies.SummaryThrough experiment and simulation, Katta et al. reveal that pushing faster and deeper recruits more and more distant mechano-electrical transduction channels during touch. The net result is a dynamic receptive field whose size and shape depends on tissue mechanics, stimulus parameters, and channel distribution within sensory neurons.

Download Full-text

Identification of gmhA, a Yersinia pestis Gene Required for Flea Blockage, by Using a Caenorhabditis elegans Biofilm System

Infection and Immunity ◽

10.1128/iai.73.11.7236-7242.2005 ◽

2005 ◽

Vol 73 (11) ◽

pp. 7236-7242 ◽

Cited By ~ 55

Author(s):

Creg Darby ◽

Sandya L. Ananth ◽

Li Tan ◽

B. Joseph Hinnebusch

Keyword(s):

Caenorhabditis Elegans ◽

Yersinia Pestis ◽

Biofilm Formation ◽

Yersinia Pseudotuberculosis ◽

C Elegans ◽

Transposon Insertion ◽

Insertion Mutants ◽

Random Screening

ABSTRACT Yersinia pestis, the cause of bubonic plague, blocks feeding by its vector, the flea. Recent evidence indicates that blockage is mediated by an in vivo biofilm. Y. pestis and the closely related Yersinia pseudotuberculosis also make biofilms on the cuticle of the nematode Caenorhabditis elegans, which block this laboratory animal's feeding. Random screening of Y. pseudotuberculosis transposon insertion mutants with a C. elegans biofilm assay identified gmhA as a gene required for normal biofilms. gmhA encodes phosphoheptose isomerase, an enzyme required for synthesis of heptose, a conserved component of lipopolysaccharide and lipooligosaccharide. A Y. pestis gmhA mutant was constructed and was severely defective for C. elegans biofilm formation and for flea blockage but only moderately defective in an in vitro biofilm assay. These results validate use of the C. elegans biofilm system to identify genes and pathways involved in Y. pestis flea blockage.

Download Full-text

Correction: Long-term C. elegans immobilization enables high resolution developmental studies in vivo

Lab on a Chip ◽

10.1039/c8lc90050g ◽

2018 ◽

Vol 18 (12) ◽

pp. 1802-1802

Author(s):

Simon Berger ◽

Evelyn Lattmann ◽

Tinri Aegerter-Wilmsen ◽

Michael Hengartner ◽

Alex Hajnal ◽

...

Keyword(s):

High Resolution ◽

Developmental Studies ◽

C Elegans

Correction for ‘Long-term C. elegans immobilization enables high resolution developmental studies in vivo’ by Simon Berger et al., Lab Chip, 2018, 18, 1359–1368.

Download Full-text

Rosemary Flowers as Edible Plant Foods: Phenolic Composition and Antioxidant Properties in Caenorhabditis elegans

Antioxidants ◽

10.3390/antiox9090811 ◽

2020 ◽

Vol 9 (9) ◽

pp. 811

Author(s):

Cristina Moliner ◽

Víctor López ◽

Lillian Barros ◽

Maria Inês Dias ◽

Isabel C. F. R. Ferreira ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Antioxidant Properties ◽

Ethanolic Extract ◽

Food Ingredient ◽

Edible Plant ◽

Phenolic Profile ◽

C Elegans ◽

Rosmarinus Officinalis L

Rosmarinus officinalis L., commonly known as rosemary, has been largely studied for its wide use as food ingredient and medicinal plant; less attention has been given to its edible flowers, being necessary to evaluate their potential as functional foods or nutraceuticals. To achieve that, the phenolic profile of the ethanolic extract of R. officinalis flowers was determined using LC-DAD-ESI/MSn and then its antioxidant and anti-ageing potential was studied through in vitro and in vivo assays using Caenorhabditis elegans. The phenolic content was 14.3 ± 0.1 mg/g extract, trans rosmarinic acid being the predominant compound in the extract, which also exhibited a strong antioxidant capacity in vitro and increased the survival rate of C. elegans exposed to lethal oxidative stress. Moreover, R. officinalis flowers extended C. elegans lifespan up to 18%. Therefore, these findings support the potential use of R. officinalis flowers as ingredients to develop products with pharmaceutical and/or nutraceutical potential.

Download Full-text

In vivo analysis of FANCD2 recruitment at meiotic DNA breaks in Caenorhabditis elegans

Scientific Reports ◽

10.1038/s41598-019-57096-1 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Marcello Germoglio ◽

Anna Valenti ◽

Ines Gallo ◽

Chiara Forenza ◽

Pamela Santonicola ◽

...

Keyword(s):

Dna Repair ◽

Caenorhabditis Elegans ◽

Genome Stability ◽

Genetic Interaction ◽

Model Systems ◽

Dna Breaks ◽

Strand Breaks ◽

C Elegans ◽

In Vivo Analysis

AbstractFanconi Anemia is a rare genetic disease associated with DNA repair defects, congenital abnormalities and infertility. Most of FA pathway is evolutionary conserved, allowing dissection and mechanistic studies in simpler model systems such as Caenorhabditis elegans. In the present study, we employed C. elegans to better understand the role of FA group D2 (FANCD2) protein in vivo, a key player in promoting genome stability. We report that localization of FCD-2/FANCD2 is dynamic during meiotic prophase I and requires its heterodimeric partner FNCI-1/FANCI. Strikingly, we found that FCD-2 recruitment depends on SPO-11-induced double-strand breaks (DSBs) but not RAD-51-mediated strand invasion. Furthermore, exposure to DNA damage-inducing agents boosts FCD-2 recruitment on the chromatin. Finally, analysis of genetic interaction between FCD-2 and BRC-1 (the C. elegans orthologue of mammalian BRCA1) supports a role for these proteins in different DSB repair pathways. Collectively, we showed a direct involvement of FCD-2 at DSBs and speculate on its function in driving meiotic DNA repair.

Download Full-text