Edwards MK et al. (1990) Trop Med Parasitol "Antigenic and dynamic properties of the surface of Onchocerca microfilariae."

Busto P, James ER, Edwards MK, Carlow CK, Philipp M

[Trop Med Parasitol, 1990]

We analyzed the antigenicity and stability of the surface of skin microfilariae (mf) of Onchocerca cervicalis, a horse parasite. These mf express antigens on their surface that are cross-reactive with the cattle parasite O. lienalis and with the human parasite O. volvulus. The surface of living O. cervicalis mf was radioiodinated using Iodogen and the labeled components were solubilized in buffers containing sodium dodecyl sulphate (SDS), or extracted with the milder detergent octyl-beta-D-glucopyranoside (OGP). Electrophoresis of this material showed seven prominent bands, one of which (14 kDa) was specifically precipitated by antisera from rabbits immunized with mf from either O. cervicalis, O. lienalis, or O. volvulus, and by human sera obtained from infected individuals in Chiapas, Mexico. Other components were precipitated by either the rabbit or the human sera. In addition, antisera from mice immunized with O. cervicalis mf bound specifically to the surface of freeze-thawed uterine O. lienalis and O. volvulus mf as detected by immunofluorescence. This fluorescence was lost from the surface of O. cervicalis mf in a temperature-dependent fashion. Live mf incubated on ice with mouse anti-mf antisera and secondary FITC-GAM, showed uniform surface fluorescence. When these mf were incubated at 37 degrees C, but not at 0 degrees C, the fluorescent pattern changed with time. First, small non-fluorescent patches arose, followed by an increasingly wide belt devoid of fluorescence, and finally, no visible fluorescence. These changes in the mf surface suggest potential mechanisms for immune evasion by filarial parasites.

Edwards MK et al. (1983) Dev Biol "Location of specific messenger RNAs in Caenorhabditis elegans by cytological hybridization."

Wood WB, Edwards MK

[Dev Biol, 1983]

We have developed an autoradiographic technique for detecting specific Caenorhabditis elegans messenger RNA molecules in situ by hybridization of labeled, cloned DNA probes to fixed tissue sections and squashes of embryos and adults. We report analyses with probes of actin and collagen gene sequences from a C. elegans genomic clone library. Hybridization is RNase sensitive and tissue specific. In adults the actin probe, which recognizes cytoplasmic as well as muscle actin mRNA, hybridizes strongly to muscle and distal gonad (ovary), somewhat less strongly to maturing oocytes, and weakly to intestine. The collagen probe hybridizes weakly to distal gonad and intestine and very strongly to subcuticular tissues, in particular to the hypodermal cells and syncytial cytoplasm of the lateral hypodermal ridges, which are the sites of cuticle synthesis. In embryos, hybridization to squashes indicates that actin message is present at fertilization, decreases during early cleavage, and then increases again during morphogenesis. By contrast, collagen message is absent until the 100-cell stage and then increases rapidly during morphogenesis. The number of cells labeled is consistent with the view that the collagen probe hybridizes to hypodermal precursor cells. We estimate that our present methods can detect messages representing about 0.2% or more of the total mRNA population, and increases in this sensitivity should be possible. Therefore, the cytological hybridization technique should be useful for determining temporal and spatial patterns of specific mRNA distributions during development, at least for abundant and

Schaeffer JM et al. (1989) Biochem J "MK-801 is a potent nematocidal agent. Characterization of MK-801 binding sites in Caenorhabditis elegans."

Turner MJ, Bergstrom AR, Schaeffer JM

[Biochem J, 1989]

MK-801, an N-methyl-D-aspartate antagonist in mammalian brain tissue, is a potent nematocidal agent. Specific MK-801 binding sites have been identified and characterized in a membrane fraction prepared from the free-living nematode Caenorhabditis elegans. The high-affinity MK-801 binding site has an apparent dissociation constant, Kd, of 225 nM. Unlike the MK-801 binding site in mammalian tissues, the C. elegans binding site is not effected by glutamate or glycine, and polyamines are potent inhibitors of specific MK-801 binding.

Schaeffer JM et al. (1994) Biochem Pharmacol "Nematocidal activity of MK-801 analogs and related drugs. Structure-activity relationships."

Bergstrom AR, Frazier EG, Underwood D, Schaeffer JM

[Biochem Pharmacol, 1994]

A series of dibenzo[a,d]cycloalkenimines were evaluated for their affinity to the (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) binding site in Caenorhabditis elegans membranes and their nematocidal activity. The (+)-MK-801 enantiomer (1) had a higher affinity (Kd = 240 nM) for its specific binding site and was a more potent nematocidal agent than the (-)-MK-801 enantiomer (-1). Ring expansion to form the dibenzo[a,d]cyclooctenimine analogs generally resulted in more potent compounds. The most potent of this series (23) was approximately 7-fold more potent than (+)-MK-801. A good correlation was established between binding affinities and nematocidal activity for all of the analogs that were tested. However, there was no correlation between binding to C. elegans membranes and affinity for mammalian MK-801 binding sites. Other noncompetitive inhibitors of the mammalian N-methyl-D-aspartate site were examined, and a series of diphenylguanidines were identified as potent competitive inhibitors of MK-801 binding to C. elegans membranes, in addition to displaying potent nematocidal activity. The most potent diphenylguanidine analog (24) was approximately 80-fold more potent than (+)-MK-801 in both its affinity for the MK-801 binding site and as a nematocidal agent. Molecular modeling studies support the hypothesis that the diphenylguanidines and MK-801 are binding to the same site and suggest that more potent compounds may be developed by effective modeling of the existing compounds.

Wojtovich AP et al. (2012) FEBS Lett "Mitochondrial ATP-sensitive potassium channel activity and hypoxic preconditioning are independent of an inwardly rectifying potassium channel subunit in Caenorhabditis elegans."

Wojtovich AP, Nehrke K, DiStefano P, Sherman T, Brookes PS

[FEBS Lett, 2012]

Hypoxic preconditioning (HP) is an evolutionarily-conserved mechanism that protects an organism against stress. The mitochondrial ATP-sensitive K(+) channel (mK(ATP)) plays an essential role in the protective signaling, but remains molecularly undefined. Several lines of evidence suggest that mK(ATP) may arise from an inward rectifying K(+) channel (Kir). The genetic model organism Caenorhabditis elegans exhibits HP and displays mK(ATP) activity. Here, we investigate the tissue expression profile of the three C. elegans Kir genes and demonstrate that mutant strains where the irk genes have been deleted either individually or in combination can be protected by HP and exhibit robust mK(ATP) channel activity in purified mitochondria. These data suggest that the mK(ATP) in C. elegans does not arise from a Kir derived channel.

Tsai RT et al. (2020) Int J Mol Sci "Maackiain Ameliorates 6-Hydroxydopamine and SNCA Pathologies by Modulating the PINK1/Parkin Pathway in Models of Parkinson's Disease in Caenorhabditis elegans and the SH-SY5Y Cell Line."

Shyu WC, Lin SZ, Tsai RT, Fu RH, Tsai CW, Kuo YH, Hung HS, Chao PM, Gao JX, Liu SP

[Int J Mol Sci, 2020]

The movement disorder Parkinson's disease (PD) is the second most frequently diagnosed neurodegenerative disease, and is associated with aging, the environment, and genetic factors. The intracellular aggregation of -synuclein and the loss of dopaminergic neurons in the substantia nigra pars compacta are the pathological hallmark of PD. At present, there is no successful treatment for PD. Maackiain (MK) is a flavonoid extracted from dried roots of <i>Sophora flavescens</i> Aiton. MK has emerged as a novel agent for PD treatment that acts by inhibiting monoamine oxidase B. In this study, we assessed the neuroprotective potential of MK in <i>Caenorhabditis elegans</i> and investigated possible mechanism of this neuroprotection in the human SH-SY5Y cell line. We found that MK significantly reduced dopaminergic neuron damage in 6-hydroxydopamine (6-OHDA)-exposed worms of the BZ555 strain, with corresponding improvements in food-sensing behavior and life-span. In transgenic worms of strain NL5901 treated with 0.25 mM MK, the accumulation of -synuclein was diminished by 27% (<i>p</i> &lt; 0.01) compared with that in untreated worms. Moreover, in worms and the SH-SY5Y cell line, we confirmed that the mechanism of MK-mediated protection against PD pathology may include blocking apoptosis, enhancing the ubiquitin-proteasome system, and augmenting autophagy by increasing <i>PINK1/parkin</i> expression. The use of small interfering RNA to downregulate parkin expression in vivo and in vitro could reverse the benefits of MK in PD models. MK may have considerable therapeutic applications in PD.

Wojtovich AP et al. (2008) Biochem Biophys Res Commun "The C. elegans mitochondrial K+(ATP) channel: a potential target for preconditioning."

Burwell LS, Sherman TA, Brookes PS, Nehrke KW, Wojtovich AP

[Biochem Biophys Res Commun, 2008]

Ischemic preconditioning (IPC) is an evolutionarily conserved endogenous mechanism whereby short periods of non-lethal exposure to hypoxia alleviate damage caused by subsequent ischemia reperfusion (IR). Pharmacologic targeting has suggested that the mitochondrial ATP-sensitive potassium channel (mK(ATP)) is central to IPC signaling, despite its lack of molecular identity. Here, we report that isolated Caenorhabditis elegans mitochondria have an mK(ATP) channel with the same physiologic and pharmacologic characteristics as the vertebrate channel. Since C. elegans also exhibit IPC, our observations provide a framework to study the role of mK(ATP) in IR injury in a genetic model organism.

Bhar S et al. (2024) Cell Chem Biol "An acyl-CoA thioesterase is essential for the biosynthesis of a key dauer pheromone in C. elegans."

Bailey LS, Mai K, Prajapati DV, Basso KB, Butcher RA, Yoon CS, Steffen CL, Han J, Bhar S, Wang Y

[Cell Chem Biol, 2024]

Methyl ketone (MK)-ascarosides represent essential components of several pheromones in Caenorhabditis elegans, including the dauer pheromone, which triggers the stress-resistant dauer larval stage, and the male-attracting sex pheromone. Here, we identify an acyl-CoA thioesterase, ACOT-15, that is required for the biosynthesis of MK-ascarosides. We propose a model in which ACOT-15 hydrolyzes the &#x3b2;-keto acyl-CoA side chain of an ascaroside intermediate during &#x3b2;-oxidation, leading to decarboxylation and formation of the MK. Using comparative metabolomics, we identify additional ACOT-15-dependent metabolites, including an unusual piperidyl-modified ascaroside, reminiscent of the alkaloid pelletierine. The &#x3b2;-keto acid generated by ACOT-15 likely couples to 1-piperideine to produce the piperidyl ascaroside, which is much less dauer-inducing than the dauer pheromone, asc-C6-MK (ascr#2, 1). The bacterial food provided influences production of the piperidyl ascaroside by the worm. Our work shows how the biosynthesis of MK- and piperidyl ascarosides intersect and how bacterial food may impact chemical signaling in the worm.

van der Keyl H et al. (1994) Dev Dyn "Caenorhabditis elegans sqt-3 mutants have mutations in the col-1 collagen gene."

Kim HY, Espey R, Edwards MK, van der Keyl H, Oke CV

[Dev Dyn, 1994]

sqt-3 mutants of Caenorhabditis elegans form dumpy larvae and adults and display allele-specific defects in locomotion, fertility, and viability. We have determined that the sqt-3 locus encodes COL-1 collagen. We physically mapped the col-1 gene to a cosmid on chromosome V whose position is consistent with the location of the sqt-3 gene. We also observed morphological defects in sqt-3 mutants at stages that correlate with the mRNA expression patterns of col-1. Sequence analysis of the col-1 gene in the three temperature-sensitive mutants revealed that each allele of sqt-3 has a unique missense mutation causing arginine or glutamic acid to replace glycine in a Gly-X-Y triple helical domain. These glycine substitutions may result in longer non-collagenous domains, which may decrease the thermal stability or impart additional flexibility to mutant trimmers. In addition, we describe four corrections to the published sequence of col-1, including one fifteen nucleotide addition that completes a conserved domain in the amino terminal coding region.

Dong C et al. (2018) J Org Chem "Comparative Ascaroside Profiling of Caenorhabditis Exometabolomes Reveals Species-Specific () and ( - 2)-Hydroxylation Downstream of Peroxisomal -Oxidation."

Dong C, Bergame C, Srinivasan J, von Reuss SH, Dolke F, Reilly DK

[J Org Chem, 2018]

Chemical communication in nematodes, such as the model organism Caenorhabditis elegans, is modulated by a variety of glycosides based on the dideoxysugar L-ascarylose. Comparative ascaroside profiling of nematode exometabolome extracts using a GC-EIMS screen reveals that several basic components including ascr#1 (asc-C7), ascr#2 (asc-C6-MK), ascr#3 (asc-C9), ascr#5 (asc-C3), and ascr#10 (asc-C9) are highly conserved among the Caenorhabditis. Three novel, side chain hydroxylated ascaroside derivatives were exclusively detected in the distantly related C. nigoni and C. afra. Molecular structures of these species-specific, putative signaling molecules were elucidated by NMR spectroscopy and confirmed by total synthesis and chemical correlations. Biological activities were evaluated using attraction assays. The identification of ()- and ( - 2)-hydroxyacyl ascarosides demonstrates how GC-EIMS-based ascaroside profiling facilitates the detection of novel ascaroside components and exemplifies how species-specific hydroxylation of ascaroside aglycones downstream of peroxisomal -oxidation increases the structural diversity of this highly conserved class of nematode signaling molecules.