48 Papers found (0.01 seconds)

Musset-Bilal F et al. (1994) Worm Breeder's Gazette "Characterization of the C. elegans Basement Membrane-Associated Protein SPARC"

Musset-Bilal F, Schwarzbauer JE, Ryan CS

[

Worm Breeder's Gazette,

1994]

Characterization of the C. elegans Basement Membrane- Associated Frederique Musset-Bilal, Carol S. Ryan, and Jean E. Schwarzbauer Department of Molecular Biology, Princeton University, Princeton NJ 08544

Townsend SR et al. (1994) Worm Breeder's Gazette "C. elegans Molecular Genetics and Long PCR."

Finelli AL, Savage C, Xie T, Padgett RW, Townsend SR

[

Worm Breeder's Gazette,

1994]

C. elegans Molecular Genetics and Long PCR Scott R. Townsend, Cathy Savage, Alyce L. Finelli, Ting Xie, and Richard W. Padgett, Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08855

Wilkinson HA et al. (1994) Worm Breeder's Gazette "Reciprocal Changes in Expression of lin-12 and lag-2 Prior to Commitment of Z1.ppp and Z4.aaa."

Greenwald IS, Wilkinson HA, Fitzgerald K

[

Worm Breeder's Gazette,

1994]

Reciprocal changes in expression of lin-12 and lag-2 prior to commitment of Z1.ppp and Z4.aaa. Hilary A. Wilkinson*, Kevin Fitzgerald and Iva Greenwald, HHMI and Dept. of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032; *Current address: Merck Research Laboratories, Rahway, NJ 07065

Ishii N et al. (1988) Worm Breeder's Gazette "partial sequence of the unc-6 gene."

Ishii N, Stern BD, Culotti JG, Hedgecock EM

[

Worm Breeder's Gazette,

1988]

In the previous issue (WBG 10(1) p.35), we reported cloning a small DNA fragment containing the Tc1 insertion which caused the unc-6 ( rh1035) mutation. Since then, we have isolated an 11.5 kb EcoRI fragment including this region from N2 DNA (NJ#14, EMBL4 vector) Alan Coulson has kindly positioned this fragment on the MRC genome map. We have now sequenced both the original 1.25 kb XbaI fragment of unc-6( rh1035) DNA (plasmid NJ#6) and a 2.7 kb HindIII fragment of N2 DNA subcloned from phage NJ#14. The 2.7 kb HindIII fragment has five exons which encode a hypothetical protein fragment of 360 residues. This fragment is not closely related to any protein in the current PIR database The last exon in the 2.7 kb HindIII fragment is followed by an intron which continues beyond the fragment. The first exon is preceded by a non-coding region which may be part of an intron or the unc-6 promoter region. In fact, a possible 21 residue signal sequence with an initiator methionine occurs in the first exon shortly upstream of the Tc1::rh1035 insertion site. TATA and CCAAT motifs occur about 90 and 120 bp upstream of the proposed initiator codon. The decanucleotide sequence TTTGCCTCTC is tandemly repeated about 200 bp upstream of this codon. [See Figure 1]

Toth, Marton L. et al. (2009) International Worm Meeting "HSF-1 is an Essential Downstream Mediator of Resveratrol-induced, SIR-2.1-dependent Longevity in C. elegans."

Soti, Csaba, Toth, Marton L., Csermely, Peter, Dancso, Balazs

[

International Worm Meeting,

2009]

Major longevity assurance mechanisms include the heat-shock response governed by the heat-shock transcription factor (HSF-1) and the metabolic stress response, exemplified by the Sir2 deacetylase. Sir2, and recently HSF-1 have been implicated in the life-span extending effect of dietary restriction. Resveratrol, a polyphenol from red wine, is a dietary restriction mimetic that induces longevity and displays an impressive therapeutic potential against various degenerative diseases via Sir2. Resveratrol has also been shown to induce the heat-shock response in mammalian cells. In this study, we have asked how the heat-shock response is involved in resveratrol-induced/Sir2-related longevity in C. elegans. We find that resveratrol specifically induces chaperone expression, thermotolerance and longevity depending on both SIR-2.1 and HSF-1. Moreover, we show that SIR-2.1 is a potent activator of HSF-1-dependent thermotolerance. Finally, we identify HSF-1 as an essential downstream effector of resveratrol-induced, SIR-2.1-dependent longevity in C. elegans. Thus, our results demonstrate a direct interaction of metabolic and proteotoxic stress responses in life-span regulation and indicate that the robustness of the heat-shock response may determine the therapeutic response to resveratrol. Marton Toth''s current address: Rutgers, The State University of NJ, Molecular Biology & Biochemistry, Piscataway, NJ.

Highmore CJ et al. (2018) MBio "Viable-but-Nonculturable Listeria monocytogenes and Salmonella enterica Serovar Thompson Induced by Chlorine Stress Remain Infectious."

Warner JC, Keevil CW, Rothwell SD, Wilks SA, Highmore CJ

[

MBio,

2018]

The microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial food-borne pathogens are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses such as chlorine, which is commonly used for fresh produce decontamination. Here, complete VBNC induction of green fluorescent protein-tagged Listeria monocytogenes and Salmonella enterica serovar Thompson was achieved by exposure to 12 and 3ppm chlorine, respectively. The pathogens were subjected to chlorine washing following incubation on spinach leaves. Culture data revealed that total viable L.monocytogenes and Salmonella Thompson populations became VBNC by 50 and 100ppm chlorine, respectively, while enumeration by direct viable counting found that chlorine caused a <1-log reduction in viability. The pathogenicity of chlorine-induced VBNC L.monocytogenes and Salmonella Thompson was assessed by using Caenorhabditis elegans Ingestion of VBNC pathogens by C.elegans resulted in a significant life span reduction (P = 0.0064 and P < 0.0001), and no significant difference between the life span reductions caused by the VBNC and culturable L.monocytogenes treatments was observed. L.monocytogenes was visualized beyond the nematode intestinal lumen, indicating resuscitation and cell invasion. These data emphasize the risk that VBNC food-borne pathogens could pose to public health should they continue to go undetected.IMPORTANCE Many bacteria are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses. VBNC cells cannot be detected by standard laboratory culture techniques, presenting a problem for the food industry, which uses these techniques to detect pathogen contaminants. This study found that chlorine, a sanitizer commonly used for fresh produce, induces a VBNC state in the food-borne pathogens Listeria monocytogenes and Salmonella enterica It was also found that chlorine is ineffective at killing total populations of the pathogens. A life span reduction was observed in Caenorhabditis elegans that ingested these VBNC pathogens, with VBNC L.monocytogenes as infectious as its culturable counterpart. These data show that VBNC food-borne pathogens can both be generated and avoid detection by industrial practices while potentially retaining the ability to cause disease.

Schuldiner M et al. (2005) Cell "Exploration of the function and organization of the yeast early secretory pathway through an epistatic miniarray profile."

Schuldiner M, Punna T, Ihmels J, Andrews B, Denic V, Weissman JS, Boone C, Greenblatt JF, Thompson NJ, Krogan NJ, Bhamidipati A, Collins SR

[

Cell,

2005]

We present a strategy for generating and analyzing comprehensive genetic-interaction maps, termed E-MAPs (epistatic miniarray profiles), comprising quantitative measures of aggravating or alleviating interactions between gene pairs. Crucial to the interpretation of E-MAPs is their high-density nature made possible by focusing on logically connected gene subsets and including essential genes. Described here is the analysis of an E-MAP of genes acting in the yeast early secretory pathway. Hierarchical clustering, together with novel analytical strategies and experimental verification, revealed or clarified the role of many proteins involved in extensively studied processes such as sphingolipid metabolism and retention of HDEL proteins. At a broader level, analysis of the E-MAP delineated pathway organization and components of physical complexes and illustrated the interconnection between the various secretory processes. Extension of this strategy to other logically connected gene subsets in yeast and higher eukaryotes should provide critical insights into the functional/organizational principles of biological systems.

Pettitt J et al. (1995) International C. elegans Meeting "pun-1(ct359): A MUTATION AFFECTING PHARYNX ATTACHMENT TO THE BUCCAL HYPODERMIS"

Pettitt J, Edgar LG, Wood WB

[

International C. elegans Meeting,

1995]

We have isolated a psoralen-induced mutation at a locus we have termed pun-1 (pharynx unattached). pun-1(ct359) homzygotes arrest as L1 larvae displaying variable defects in body morphology, ranging from a mild dumpy phenotype to animals which appear to have failed to elongate properly and have a severely disrupted hypodermis. ct359 homozygotes, however, also exhibit a failure of the buccal capsule (the cuticle lining the buccal cavity) to attach to the buccal hypodermis. This phenotype is similar to that observed in animals transgenic for a truncated version of cdh-3, a cadherin-related gene (see other abstract by Pettitt et al.). We are now using various markers to more fully characterize the pun-1(ct359) phenotype. In particular we would like to determine which cells are involved in the Pun phenotype and confirm that the phenotype is due to a failure of cell adhesion and not merely the absence of the cells involved. The anterior part of the buccal capsule is secreted by the arcade cells and the posterior part by the pharyngeal epidermal cells (Wright and Thompson, Can. J. Zool. 59: 1952-196). We assume that the arcade cells, and/or hyp1 cells are affected in pun-1 homozygotes, since the unattached pharynx in these animals retains the buccal capsule, suggesting that the pharyngeal epidermal cells are unaffected. pun-1 has been mapped to LGI and we are currently refining its map position.

Mok, C.A. et al. (2017) International Worm Meeting "Repeat region inversion probes: a high-throughput estimation of rDNA locus copy number in Caenorhabditis elegans."

Mok, C.A., Queitsch, C., Waterston, R.H., Morton, E.A

[

International Worm Meeting,

2017]

In C. elegans the major rDNA locus lies on the right end of LGI. A 7.2 kb repeat contains the rrn-1(18s rRNA), rrn-2(5.8s rRNA), and rrn-3(26s rRNA) gene. The N2 laboratory strain has been estimated to contain between 80-100 copies (Sulston and Brenner 1974; C. elegans sequencing consortium 1998). However, the copy number was found to vary between 55-130 copies of this region across 2007 mutagenized strains using whole genome sequencing (WGS) (Thompson et al. 2013). In contrast, wild isolates have estimated copy numbers of the LGI locus ranging as low as 68 and as high as 418 (Thompson et al. 2013). Although the standard laboratory strain N2 is usually considered to be isogenic, we wondered if recombination errors in meiosis might produce variable copy numbers of this repeat that could be associated with phenotypic differences observed in areas such as lifespan, stress response, and mutation penetrance. Two methods for estimating rDNA copy number are contour-clamped homogeneous electric field (CHEF) gels and WGS. CHEF gels, the gold standard in rDNA copy number estimation, require large numbers of worms to generate a sample. WGS, however, requires far less sample input but is costly with large sample numbers. Since examining the effect of rDNA copy number on phenotype variation requires working with small populations and multiple biological replicates, we devised a targeted sequencing approach that operates well with low sample input and is cost-efficient. Briefly, the method uses molecular inversion probes (MIPs, Hiatt et al. 2013) to sample regions of the rDNA locus as well as single-copy sites of the C. elegans genome. These probes are used in a Repeat Region Inversion Probe (RRIP) capture reaction combining genomic DNA samples with a special normalization plasmid containing single-copy versions of the rDNA locus and the other RRIP genomic targets. The plasmid versions, however, contain single nucleotide variants to distinguish these from the endogenous loci. After sequencing, reads from both plasmid and genomic DNA are analysed to generate an rDNA copy number estimate. We investigated the accuracy of the RRIP approach by testing wild isolate genomic samples that were previously sequenced by WGS in the Million Mutation Project. Our RRIP approach provides similar estimates of rDNA copy numbers with only a fraction of the reads required for WGS. Thus, RRIP is able to estimate rDNA copy number from small amounts of genomic DNA, for low sequencing cost, in a short period of time (3-day turnaround). With RRIP we can study small populations, potentially at a timescale of a single generation to investigate the influence of rDNA copy number variation in lifespan and overall health.

Dent JA et al. (1997) International C. elegans Meeting "avr-15 encodes glutamate- and ivermectin-gated chloride channel subunits."

Dent JA, Avery L

[

International C. elegans Meeting,

1997]

The pair of M3 pharyngeal motor neurons form inhibitory syn apses on pharyngeal muscles pm4 and pm5 (Albertson and Thompson, 1976). In an avr-15 mutant, M3 IPSPs are absent and iontophoretically applied glutamate no longer has a hyper polarizing effect on the pharyngeal muscle action potential. avr-15 also confers sensitivity to ivermectin, a widely used anthelmintic drug. avr-15 encodes two alternatively spliced channel subunits, GluClalpha2A and GluClalpha2B, that belong to the glutamate-gated chloride channel subunit family first described by Cully et al. (1994). A and B are essentially identical except that GluCla2A has an unusual addition of 202 amino acids at the beginning of the amino terminal domain. Promoter fusions of GluClalpha2A with GFP are expressed in pharyngeal corpus muscle pm4 and the isthmus muscle pm5, as expected, and in some extrapharyngeal neurons in the head. A full-length GluCla2AcDNA::GFP fusion appears to localize near the M3 synapse in pm4. To look at the pharmacological binding proper ties of the AVR-15/GluClalpha2 channel subunits, we expressed GluClalpha2A in Xenopus oocytes. It formed a homomeric channel that responded to both glutamate and ivermectin. The glutamate response desensitizes rapidly with a maximal response around 5mM. The ivermectin response also desensitizes but to a much lesser extent and is irreversible. Thus AVR-15/GluClalpha2 medi ates inhibitory glutamatergic neurotransmission by M3 and ivermectin sensitivity in the pharynx.

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