Hosono R et al. (1985) Zoolog Sci "Properties of the unc-52 gene and its related mutations in the nematode C. elegans."

Kuno S, Hosono R

[Zoolog Sci, 1985]

The mutations in the unc-52 gene show a stage-dependent uncoordinated (Unc) phenotype and belong to either severely or mildly paralyzed Unc. One recessive allele (cn10) of the unc-52 gene, belonging to one of the most severely paralyzed group, and its revertans are depicted. Isolated as a revertant of the severe allele, unc-52 (cn10) cnDp1 (f) produces two types of progeny; parental severe-type and recovered mild-type Unc. Genetic evidence is presented showing that the property of cnDp1 is brought about by the presence (i.e., mild type) or absence (i.e., severe type) of the free chromosomal fragment containing the unc-52 (cn10) gene. Based on the properties of the strain containing cn Dp1 (f), the role of the unc-52 gene is

Sassa T et al. (1987) Neurochem Int "Choline acetyltransferase from a temperature-sensitive mutant of caenorhabditis elegans."

Hosono R, Sassa T, Kuno S

[Neurochem Int, 1987]

A temperature dependent paralytic mutant of C. elegans was isolated and mapped to be an allele of the cha-1 gene that has been shown to be the structural gene for acetyl-CoA: choline-O-acetyltransferase (EC 2.3.1.6; ChAT) (Hosono et al., J. Exp. Zool.235, 409-421, 1985; Rand and Russell, Genetics106, 227-248, 1984). In crude extracts from the mutant, ChAT activity was present when assayed at a permissive temperature but not detectable at a temperature that provoked abnormal phenotypes. The mutant ChAT was purified to a specific activity of 2.9 nmol of product min (-1) per mg of protein at 10 degrees C and its enzymatic properties were studied by comparison with the wild-type enzyme. The temperaturesensitivity of the mutant ChAT was so remarkable that no activity was detected over 20 degrees C. This inactivation at higher temperature appeared to be partly reversible. The Km values of the mutant enzyme for choline and acetyl-CoA were about twice of those in the wild-type enzyme, but increased 10- to 20-fold in the presence of high salt concentrations. The mutant enzyme was also more sensitive to sulfhydryl reagents. These findings indicate that depending upon changes in the physical environment, the mutant ChAT may lose the normal-conformation leading to inactivation.

Hosono R et al. (1989) Zoological Science "Spontaneous mutations of trichlorfon resistance in the nematode, Caenorhabditis elegans."

Sassa T, Kuno S, Hosono R

[Zoological Science, 1989]

Spontaneous trichlorfon-resistant mutations were isolated in Caenorhabditis elegans var. Bergerac and its derived mutator strains. Of these, six uncoordinated mutations were assigned by complementation analysis to the unc-13(cn490), unc-17(cn355), unc-18(cn347), unc-10(cn257), unc-3(cn4146) and unc-41(cn252) genes. Resistance of these mutations to acetylcholinesterase (AChE) inhibitors is partial, with the extent dependent on the mutations. These mutations fall into two classes based on acetylcholine (ACh) levels, that is, the normal ACh levels in unc-10 and unc-3 mutations and the abnormally high ACh levels in unc-13, unc-17, unc-41 and unc-18 mutations. Mutations in the latter gene groups are also accompanied by growth retardation and small body size in adulthood. Double mutants were constructed between the six trichlorfon-resistant strains together with the cha-1*unc-17 complex gene alleles which are also resistant to trichlorfon. All doubles constructed between trichlorfon-resistant strains survived and their properties

Hosono R et al. (1985) J Exp Zool "Temperature-sensitive mutations causing reversible paralysis in Caenorhabditis elegans."

Midsukami M, Kuno S, Hosono R

[J Exp Zool, 1985]

A method has been developed for the isolation of temperature- dependent paralytic mutants of the nematode Caenorhabditis elegans, based on a screening procedure using short-time exposure to 30 degrees C. Of ten mutants isolated, eight lose their motilities between 30 degrees C and 33 degrees C without prominent changes in body forms. The other two strains that are mainly described in this report are accompanied by alterations in body forms. One mutation, cn101, is recessive and an allele of cha-1. The cn101 mutant shows reversible paralysis at 30 degrees, accompanied by a hypercontracted and coiled body form. At the restrictive temperature, the strain is resistant to all tested inhibitors of acetylcholinesterase (AChE). Another mutation, designated mah-2 (cn110), is a sex-linked semidominant that is mapped as 0.6 map units left of dpy-6. The cn110 mutant is rapidly paralyzed at the restrictive temperature and has a straight and rigid body form; the mutant rapidly recovers when the temperature is lowered. No disorganization of the muscle structure was detected by polarized light and electron microscopic inspection.

Hosono R et al. (1987) J Neurochem "Mutations affecting acetylcholine levels in the nematode Caenorhabditis elegans."

Hosono R, Kuno S, Sassa T

[J Neurochem, 1987]

Gene cha-1.unc-17 of the nematode Caenorhabditis elegans is a complex gene, consisting of at least two complementation groups. One part (cha-1 region) of the gene encodes the enzyme choline acetyltransferase (ChAT), but the function of the other part (unc-17 region) is still unclear. We measured the ChAT activity and ACh levels of the cha-1 and unc-17 complex gene mutants. We show here that alterations in ACh levels, rather than the ChAT activity, reflect abnormal phenotypes accompanying cha-1.unc-17 mutations, that is, the decreased ACh levels in cha-1 mutations and abnormal accumulation in unc-17 mutations. Our results suggest that the unc-17 region may encode functions necessary for storage and/or release of ACh at the presynaptic level.

Hosono R et al. (1989) Exp Gerontol "Alterations of life span in the nematode Caenorhabditis elegans under monoxenic culture conditions."

Hosono R, Nishimoto S, Kuno S

[Exp Gerontol, 1989]

The nematode Caenorhabditis elegans was cultured monoxenically with E. coli as a food source and the influence of the bacterial growth conditions on the life span was studied. When bacterial growth was restricted by reducing the concentration of bactopeptone, which was supplied as the energy source in nematode growth medium (NGM), the nematode's life span tended to be prolonged without a marked effect on postembryonic development. The effect of bactopeptone on the life span was clearly observed during the postreproductive period (that is, after the egg-laying stage of the wild-type C. elegans) rather than during the larval to young adult stage. Evidence is presented that this alteration of the life span was not brought about by any factor in the bactopeptone but by the concentration of bacteria.

Vinci CR et al. (2007) J Biol Chem "Recognition of age-damaged (R,S)-adenosyl-L-methionine by two methyltransferases in the yeast Saccharomyces cerevisiae."

Vinci CR, Clarke SG

[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.

Fanning S et al. (2018) Mol Cell "Lipidomic Analysis of -Synuclein Neurotoxicity Identifies Stearoyl CoA Desaturase as a Target for Parkinson Treatment."

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.

Vandecandelaere I et al. (2017) PLoS One "Metabolic activity, urease production, antibiotic resistance and virulence in dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus."

Deforce D, Coenye T, Van Nieuwerburgh F, Vandecandelaere I

[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.

Vandecandelaere I et al. (2014) Pathog Dis "Protease production by Staphylococcus epidermidis and its effect on Staphylococcus aureus biofilms."

Coenye T, Vandecandelaere I, Depuydt P, Nelis HJ

[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.