Effectiveness of Cleaners and Sanitizers in Killing Salmonella Newport in the Gut of a Free-Living Nematode, Caenorhabditis elegans

2004 ◽  
Vol 67 (10) ◽  
pp. 2151-2157 ◽  
Author(s):  
STEPHEN J. KENNEY ◽  
GARY L. ANDERSON ◽  
PHILLIP L. WILLIAMS ◽  
PATRICIA D. MILLNER ◽  
LARRY R. BEUCHAT

Caenorhabditis elegans, a free-living nematode found in soil, has been shown to ingest human enteric pathogens, thereby potentially serving as a vector for preharvest contamination of fruits and vegetables. A study was undertaken to evaluate the efficacy of cleaners and sanitizers in killing Salmonella enterica serotype Newport in the gut of C. elegans. Adult worms were fed nalidixic acid–adapted cells of Escherichia coli OP50 (control) or Salmonella Newport for 24 h, washed, placed on paper discs, and incubated at temperatures of 4 or 20°C and relative humidities of 33 or 98% for 24 h. Two commercial cleaners (Enforce and K Foam Lo) and four sanitizers (2% acetic acid, 2% lactic acid, Sanova, and chlorine [50 and 200 μg/ml]) were applied to worms for 0, 2, or 10 min. Populations of E. coli and Salmonella Newport (CFU per worm) in untreated and treated worms were determined by sonicating worms in 0.1% peptone and surface plating suspensions of released cells on tryptic soy agar containing nalidixic acid. Populations of Salmonella Newport in worms exposed to 33 or 98% relative humidity at 4°C or 33% relative humidity at 20°C were significantly (P ≤ 0.05) lower than the number surviving exposure to 98% relative humidity at 20°C. In general, treatment of desiccated worms with cleaners and sanitizers was effective in significantly (P ≤ 0.05) reducing the number of ingested Salmonella Newport. Results indicate that temperature and relative humidity influence the survival of Salmonella Newport in the gut of C. elegans, and cleaners and sanitizers may not eliminate the pathogen.

Nematology ◽  
2005 ◽  
Vol 7 (5) ◽  
pp. 761-766 ◽  
Author(s):  
Nancy Lu ◽  
Rekha Balachandar

AbstractCaenorhabditis elegans is a free-living nematode cultured in an axenic medium, the Caenorhabditis elegans Maintenance Medium (CeMM), which contains B-vitamins, salts, amino acids, nucleic acid substituents, growth factors and glucose as an energy source. After initial experiments established that either pantothenate or pantethine would satisfy the vitamin B5 requirement in C. elegans, reproduction in the nematodes was measured in eight equimolar concentrations of calcium pantothenate, pantethine or coenzyme A. The optimal levels for pantothenate were found to be 7.5, 30 and 120 μg ml−1. The optimal levels for pantethine and coenzyme A were found to be 35 μg ml−1 and 100 μg ml−1, respectively. Among the three compounds, coenzyme A (at 100 μg/ml) supported a significantly greater population growth and, perhaps, is a more metabolically active form. Mild toxicity was demonstrated for pantothenate at 480μg ml−1, pantethine at 560 and 140 μg ml−1, and coenzyme A was found to exhibit toxicity at 410 and 1700 μg ml−1. Based on our results, we recommend that in the future the CeMM could be supplemented with pantothenate (7.5 μg ml−1) alone.


2003 ◽  
Vol 69 (7) ◽  
pp. 4103-4110 ◽  
Author(s):  
Krishaun N. Caldwell ◽  
Barbara B. Adler ◽  
Gary L. Anderson ◽  
Phillip L. Williams ◽  
Larry R. Beuchat

ABSTRACT Free-living nematodes are known to ingest food-borne pathogens and may serve as vectors to contaminate preharvest fruits and vegetables. Caenorhabditis elegans was selected as a model to study the effectiveness of sanitizers in killing Salmonella enterica serotype Poona ingested by free-living nematodes. Aqueous suspensions of adult worms that had fed on S. enterica serotype Poona were treated with produce sanitizers. Treatment with 20 μg of free chlorine/ml significantly (α = 0.05) reduced the population of S. enterica serotype Poona compared to results for treating worms with water (control). However, there was no significant difference in the number of S. enterica serotype Poona cells surviving treatments with 20 to 500 μg of chlorine/ml, suggesting that reductions caused by treatment with 20 μg of chlorine/ml resulted from inactivation of S. enterica serotype Poona on the surface of C. elegans but not cells protected by the worm cuticle after ingestion. Treatment with Sanova (850 or 1,200 μg/ml), an acidified sodium chlorite sanitizer, caused reductions of 5.74 and 6.34 log10 CFU/worm, respectively, compared to reductions from treating worms with water. Treatment with 20 or 40 μg of Tsunami 200/ml, a peroxyacetic acid-based sanitizer, resulted in reductions of 4.83 and 5.34 log10 CFU/worm, respectively, compared to numbers detected on or in worms treated with water. Among the organic acids evaluated at a concentration of 2%, acetic acid was the least effective in killing S. enterica serotype Poona and lactic acid was the most effective. Treatment with up to 500 μg of chlorine/ml, 1% hydrogen peroxide, 2,550 μg of Sanova/ml, 40 μg of Tsunami 200/ml, or 2% acetic, citric, or lactic acid had no effect on the viability or reproductive behavior of C. elegans. Treatments were also applied to cantaloupe rind and lettuce inoculated with S. enterica serotype Poona or C. elegans that had ingested S. enterica serotype Poona. Protection of ingested S. enterica serotype Poona against sanitizers applied to cantaloupe was not evident; however, ingestion afforded protection of the pathogen on lettuce. These results indicate that S. enterica serotype Poona ingested by C. elegans may be protected against treatment with chlorine and other sanitizers, although the basis for this protection remains unclear.


1998 ◽  
Vol 336 (3) ◽  
pp. 545-550 ◽  
Author(s):  
Akram A. DA'DARA ◽  
Rolf D. WALTER

S-Adenosylmethionine decarboxylase (SAMDC) is a major regulatory enzyme in the polyamine biosynthesis and is considered a potentially important drug target for the chemotherapy of proliferative and parasitic diseases. To study regulatory mechanisms which are involved in the expression of SAMDC of the free-living nematode Caenorhabditis elegans, we have isolated the SAMDC gene and cDNA. Genomic Southern-blot analysis suggests that the C. elegans SAMDC is encoded by a single-copy gene which spans 3.9 kb and consists of six exons and five introns. The first two introns are located in the 5´-untranslated region (UTR). Analyses of the 5´-flanking region of the gene revealed several consensus sequences for the binding of different transcription factors such as CBP, AP2, cMyb, VPE2 and others. The C. elegans SAMDC mRNA possesses an open reading frame (ORF) which encodes a polypeptide of 368 amino acids, corresponding to a SAMDC proenzyme with a calculated molecular mass of 42141 Da. The active form of the C. elegans SAMDC is a heterotetramer, consisting of two subunits of 32 and 10 kDa derived from cleavage of the pro-enzyme. The SAMDC mRNA has an unusually long 5´-UTR of 477 nucleotides. This region has a small ORF which could encode a putative peptide of 17 residues. Moreover, the C. elegans SAMDC mRNA is trans-spliced with the 22 nucleotides spliced leader sequence at the 5´-end.


2001 ◽  
Vol 357 (1) ◽  
pp. 167-182 ◽  
Author(s):  
Yann GUÉRARDEL ◽  
Luis BALANZINO ◽  
Emmanuel MAES ◽  
Yves LEROY ◽  
Bernadette CODDEVILLE ◽  
...  

The free-living nematode Caenorhabditis elegans is a relevant model for studies on the role of glycoconjugates during development of multicellular organisms. Several genes coding for glycosyltransferases involved in the synthesis of N- and O-linked glycans have already been isolated, but, apart from repetitive dimers of glycosaminoglycans, no detailed structure of either type of component has been published so far. This study aimed to establish the structures of the major O-glycans synthesized by C. elegans to give an insight into the endogenous glycosyltransferase activities expressed in this organism. By the use of NMR and MS, we have resolved the sequence of seven of these components that present very unusual features. Most of them were characterized by the type-1 core substituted on Gal and/or GalNAc by (β1–4)Glc and (β1–6)Glc residues. Another compound exhibited the GalNAc(β1–4)N-acetylglucosaminitol sequence in the terminal position, to which was attached a tetramer of β-Gal substituted by both Fuc and 2-O-methyl-fucose residues. Our experimental procedure led also to the isolation of glycosaminoglycan-like components and oligomannosyl-type N-glycans. In particular, the data confirmed that C. elegans synthesizes the ubiquitous linker sequence GlcA(β1–3)Gal(β1–3)Gal(β1–4)Xyl.


Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 314-320 ◽  
Author(s):  
Veeren M Chauhan ◽  
David I Pritchard

AbstractCaenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model to evaluate vaccine responses to intestinal proteins from hematophagous nematode parasites, such as Necator americanus. Human erythrocytes, fluorescently labelled with tetramethylrhodamine succinimidyl ester, demonstrated a stable bright emission and facilitated visualization of feeding events with fluorescent microscopy. C. elegans were observed feeding on erythrocytes and were shown to rupture red blood cells upon capture to release and ingest their contents. In addition, C. elegans survived equally on a diet of erythrocytes. There was no statistically significant difference in survival when compared with a diet of Escherichia coli OP50. The enzymes responsible for the digestion and detoxification of haem and haemoglobin, which are key components of the hookworm vaccine, were found in the C. elegans intestine. These findings support our postulate that free-living nematodes could provide a model for the assessment of neutralizing antibodies to current and future hematophagous parasite vaccine candidates.


2014 ◽  
Vol 60 (1) ◽  
Author(s):  
Romina E. D’Almeida ◽  
María R. Alberto ◽  
Phillip Morgan ◽  
Margaret Sedensky ◽  
María I. Isla

AbstractZuccagnia punctata Cav. (Fabaceae), commonly called jarilla macho or pus-pus, is being used in traditional medicine as an antiseptic, anti-inflammatory and to relieve muscle and bone pain. The aim of this work was to study the anthelmintic effects of three structurally related flavonoids present in aerial parts of Z. punctata Cav. The biological activity of the flavonoids 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2´,4´-dihydroxychalcone (DHC) was examined in the free-living nematode Caenorhabditis elegans. Our results showed that among the assayed flavonoids, only DHC showed an anthelmintic effect and alteration of egg hatching and larval development processes in C. elegans. DHC was able to kill 50% of adult nematodes at a concentration of 17 μg/mL. The effect on larval development was observed after 48 h in the presence of 25 and 50 μg/mL DHC, where 33.4 and 73.4% of nematodes remained in the L3 stage or younger. New therapeutic drugs with good efficacy against drug-resistant nematodes are urgently needed. Therefore, DHC, a natural compound present in Z. punctata, is proposed as a potential anthelmintic drug.


2008 ◽  
Vol 99 (6) ◽  
pp. 3136-3143 ◽  
Author(s):  
S. R. Lockery ◽  
K. J. Lawton ◽  
J. C. Doll ◽  
S. Faumont ◽  
S. M. Coulthard ◽  
...  

With a nervous system of only 302 neurons, the free-living nematode Caenorhabditis elegans is a powerful experimental organism for neurobiology. However, the laboratory substrate commonly used in C. elegans research, a planar agarose surface, fails to reflect the complexity of this organism's natural environment, complicates stimulus delivery, and is incompatible with high-resolution optophysiology experiments. Here we present a new class of microfluidic devices for C. elegans neurobiology and behavior: agarose-free, micron-scale chambers and channels that allow the animals to crawl as they would on agarose. One such device mimics a moist soil matrix and facilitates rapid delivery of fluid-borne stimuli. A second device consists of sinusoidal channels that can be used to regulate the waveform and trajectory of crawling worms. Both devices are thin and transparent, rendering them compatible with high-resolution microscope objectives for neuronal imaging and optical recording. Together, the new devices are likely to accelerate studies of the neuronal basis of behavior in C. elegans.


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