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[
Mid-west Worm Meeting,
2002]
The odd-skipped (odd) gene of Drosophila was the first identified member of a small subfamily of C2H2 zinc finger genes. By characterizing the developmental functions of various odd homologues, we hope to understand the evolution of this family of transcription factors. In Drosophila, odd and its paralogs show divergent roles during embryonic pattern formation: odd has a genetically-unique role as a pair-rule segmentation gene and is also expressed in numerous tissues during organogenesis, both odd and the very closely-linked gene sob are expressed in a segment-polarity like pattern, and a third linked paralog (bowel) is regulated by the terminal hierarchy and plays a key role in gut development. The worm genome sequence includes two homologues, which, unlike the fly genes, are not linked. As with the Drosophila paralogs, sequence homology is limited to the zinc finger regions, and potential orthologous relationships are not apparent from sequence data. Results of our investigation into the functions and expression of these worm genes will be presented.
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[
Worm Breeder's Gazette,
1994]
THE MATERNAL GENE SKN-4 AND THE SPECIFICATION OF VENTRAL BLASTOMERE FATES IN THE EARLY C. ELEGANS EMBRYO Bruce Bowerman, Paula R. Martin, Christopher J. Thorpe, and Christopher A. Shelton. The Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.
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[
Chem Soc Rev,
2009]
On December 10, 2008 Osamu Shimomura, Martin Chalfie and Roger Tsien were awarded the Nobel Prize in Chemistry for "the discovery and development of the green fluorescent protein, GFP". The path taken by this jellyfish protein to become one of the most useful tools in modern science and medicine is described. Osamu Shimomura painstakingly isolated GFP from hundreds of thousands of jellyfish, characterized the chromophore and elucidated the mechanism of Aequorean bioluminescence. Martin Chalfie expressed the protein in E. coli and C. elegans, and Roger Tsien developed a palette of fluorescent proteins that could be used in a myriad of applications.
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[
Worm Breeder's Gazette,
1994]
Cytology of degenerin-induced cell death in the PVM neuron David H. Hall, Guoqiang Gu+, Lei Gong#, Monica Driscoll#, and Martin Chalfie+, * Dept. Neuroscience, Albert Einstein College of Medicine, Bronx, N.Y. 10461 + Dept. Biological Sciences, Columbia University, New York, N.Y. 10027 # Dept. Molecular Biology and Biochemistry, Rutgers University, Piscataway, N.J. 08855
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[
Worm Breeder's Gazette,
1990]
In the previous issue of the WBG (Vol. 11, #3, page 20) we reported the isolation of a cysteine protease clone from a mixed-stage C. elegans cDNA library. This library was originally obtained from Chris Martin and not from Cynthia Kenyon as was reported in the article. Our apologies for any misunderstanding caused by this oversight.
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[
J Med Entomol,
1989]
Intracellular melanization responses to developing larvae of Brugia species (B. malayi (Buckley), B. pahangi (Buckley and Edeson), and B. patei (Buckley, Nelson, and Heisch] in the thoracic muscle fibers of eight strains of Anopheles quadrimaculatus Say were first observed 48 to 72 h after an infective blood meal. Three to 4 d later, large numbers of melanized first-stage larvae were found within the thoracic muscle fibers. These intracellular responses were in addition to the extracellular responses to microfilariae and microfilarial sheaths of B. pahangi in the abdominal hemocoel of An. quadrimaculatus described in literature. Simultaneously, normal development of larvae of the three Brugia species also was observed in all eight strains of An. quadrimaculatus. Comparisons of melanized first-stage larvae and normally developing larvae of the three Brugia species in the thoracic muscle fibers of the eight strains of An. quadrimaculatus showed that there were distinct variations in numbers of melanized and developing larvae and percentage of females with melanized and developing larvae in different strains. Numbers of melanized first-stage larvae reflected the extent of refractoriness of An. quadrimaculatus strains. Fully melanized larvae showed no abnormalities in parasite organelles, indicating that refractoriness is due to an enhanced ability of the host to recognize the living parasite. Further comparison among the strains suggested that the mutants, Yellow Larvae and Vero Beach Colony were significantly more susceptible, and Red Stripe was the most refractory to all three Brugia species. Thus, the gene(s) controlling susceptibility and refractoriness to all three Brugia species probably occurs on the same autosomal chromosome as the mutations in these strains. The significance of intracellular melanization of filarial larvae is discussed with reference to the melanization responses to different parasites in other mosquitoes.
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[
J Biol Chem,
2007]
The biological methyl donor, S adenosylmethionine (AdoMet), can exist in two diastereoisomeric states with respect to its sulfonium ion. The "S" configuration, (S,S)AdoMet, is the only form that is produced enzymatically as well as the only form used in almost all biological methylation reactions. Under physiological conditions, however, the sulfonium ion can spontaneously racemize to the "R" form, producing (R,S)AdoMet. As of yet, (R,S)AdoMet has no known physiological function and may inhibit cellular reactions. In this study, two enzymes have been found in Saccharomyces cerevisiae that are capable of recognizing (R,S)AdoMet and using it to methylate homocysteine to form methionine. These enzymes are the products of the SAM4 and MHT1 genes, previously identified as homocysteine methyltransferases dependent upon AdoMet and S-methylmethionine respectively. We find here that Sam4 recognizes both (S,S) and (R,S)AdoMet, but its activity is much higher with the R,S form. Mht1 reacts with only the R,S form of AdoMet while no activity is seen with the S,S form. R,S-specific homocysteine methyltransferase activity is also shown here to occur in extracts of Arabidopsis thaliana, Drosophila melanogaster, and Caenorhabditis elegans, but has not been detected in several tissue extracts of Mus musculus. Such activity may function to prevent the accumulation of (R,S)AdoMet in these organisms.
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Lou Y, Haque A, Freyzon Y, Farese RV, Terry-Kantor E, Hofbauer HF, Termine D, Welte MA, Barrasa MI, Imberdis T, Noble T, Lindquist S, Clish CB, Jaenisch R, Pincus D, Nuber S, Sandoe J, Kohlwein SD, Kim TE, Ho GPH, Ramalingam N, Walther TC, Baru V, Selkoe D, Srinivasan S, Landgraf D, Soldner F, Dettmer U, Fanning S, Becuwe M, Newby G
[
Mol Cell,
2018]
In Parkinson's disease (PD), -synuclein (S) pathologically impacts the brain, a highly lipid-rich organ. We investigated how alterations in S or lipid/fattyacid homeostasis affect each other. Lipidomic profiling of human S-expressing yeast revealed increases in oleic acid (OA, 18:1), diglycerides, and triglycerides. These findings were recapitulated in rodent and human neuronal models of S dyshomeostasis (overexpression; patient-derived triplication or E46K mutation; E46K mice). Preventing lipid droplet formation or augmenting OA increased S yeast toxicity; suppressing the OA-generating enzyme stearoyl-CoA-desaturase (SCD) was protective. Genetic or pharmacological SCD inhibition ameliorated toxicity in S-overexpressing rat neurons. In a C.elegans model, SCD knockout prevented S-induced dopaminergic degeneration. Conversely, we observed detrimental effects of OA on S homeostasis: in human neural cells, excess OA caused S inclusion formation, which was reversed by SCD inhibition. Thus, monounsaturated fatty acid metabolism is pivotal for S-induced neurotoxicity, and inhibiting SCD represents a novel PD therapeutic approach.
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[
PLoS One,
2017]
In this paper, the metabolic activity in single and dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus isolates was investigated. Our results demonstrated that there was less metabolic activity in dual species biofilms compared to S. aureus biofilms. However, this was not observed if S. aureus and S. epidermidis were obtained from the same sample. The largest effect on metabolic activity was observed in biofilms of S. aureus Mu50 and S. epidermidis ET-024. A transcriptomic analysis of these dual species biofilms showed that urease genes and genes encoding proteins involved in metabolism were downregulated in comparison to monospecies biofilms. These results were subsequently confirmed by phenotypic assays. As metabolic activity is related to acid production, the pH in dual species biofilms was slightly higher compared to S. aureus Mu50 biofilms. Our results showed that S. epidermidis ET-024 in dual species biofilms inhibits metabolic activity of S. aureus Mu50, leading to less acid production. As a consequence, less urease activity is required to compensate for low pH. Importantly, this effect was biofilm-specific. Also S. aureus Mu50 genes encoding virulence-associated proteins (Spa, SplF and Dps) were upregulated in dual species biofilms compared to monospecies biofilms and using Caenorhabditis elegans infection assays, we demonstrated that more nematodes survived when co-infected with S. epidermidis ET-024 and S. aureus mutants lacking functional spa, splF or dps genes, compared to nematodes infected with S. epidermidis ET-024 and wild- type S. aureus. Finally, S. epidermidis ET-024 genes encoding resistance to oxacillin, erythromycin and tobramycin were upregulated in dual species biofilms and increased resistance was subsequently confirmed. Our data indicate that both species in dual species biofilms of S. epidermidis and S. aureus influence each other's behavior, but additional studies are required necessary to elucidate the exact mechanism(s) involved.
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[
Pathog Dis,
2014]
Due to the resistance of Staphylococcus aureus to several antibiotics, treatment of S. aureus infections is often difficult. As an alternative to conventional antibiotics, the field of bacterial interference is investigated. Staphylococcus epidermidis produces a serine protease (Esp) which inhibits S. aureus biofilm formation and which degrades S. aureus biofilms. In this study, we investigated the protease production of 114 S. epidermidis isolates, obtained from biofilms on endotracheal tubes (ET). Most of the S. epidermidis isolates secreted a mixture of serine, cysteine and metalloproteases. We found a link between high protease production by S. epidermidis and the absence of S. aureus in ET biofilms obtained from the same patient. Treating S. aureus biofilms with the supernatant (SN) of the most active protease producing S. epidermidis isolates resulted in a significant biomass decrease compared to untreated controls, while the number of metabolically active cells was not affected. The effect on the biofilm biomass was mainly due to serine proteases. Staphylococcus aureus biofilms treated with the SN of protease producing S. epidermidis were thinner with almost no extracellular matrix. An increased survival of Caenorhabditis elegans, infected with S. aureus Mu50, was observed when the SN of protease positive S. epidermidis was added.