Wypijewska A et al. (2012) Biochemistry "7-methylguanosine diphosphate (m(7)GDP) is not hydrolyzed but strongly bound by decapping scavenger (DcpS) enzymes and potently inhibits their activity."

Wypijewska A, Darzynkiewicz E, Davis RE, Jemielity J, Bojarska E, Lukaszewicz M, Stepinski J

[Biochemistry, 2012]

Decapping scavenger (DcpS) enzymes catalyze the cleavage of a residual cap structure following 3' 5' mRNA decay. Some previous studies suggested that both m(7)GpppG and m(7)GDP were substrates for DcpS hydrolysis. Herein, we show that mononucleoside diphosphates, m(7)GDP (7-methylguanosine diphosphate) and m(3)(2,2,7)GDP (2,2,7-trimethylguanosine diphosphate), resulting from mRNA decapping by the Dcp1/2 complex in the 5' 3' mRNA decay, are not degraded by recombinant DcpS proteins (human, nematode, and yeast). Furthermore, whereas mononucleoside diphosphates (m(7)GDP and m(3)(2,2,7)GDP) are not hydrolyzed by DcpS, mononucleoside triphosphates (m(7)GTP and m(3)(2,2,7)GTP) are, demonstrating the importance of a triphosphate chain for DcpS hydrolytic activity. m(7)GTP and m(3)(2,2,7)GTP are cleaved at a slower rate than their corresponding dinucleotides (m(7)GpppG and m(3)(2,2,7)GpppG, respectively), indicating an involvement of the second nucleoside for efficient DcpS-mediated digestion. Although DcpS enzymes cannot hydrolyze m(7)GDP, they have a high binding affinity for m(7)GDP and m(7)GDP potently inhibits DcpS hydrolysis of m(7)GpppG, suggesting that m(7)GDP may function as an efficient DcpS inhibitor. Our data have important implications for the regulatory role of m(7)GDP in mRNA metabolic pathways due to its possible interactions with different cap-binding proteins, such as DcpS or eIF4E.

O'Connell EM et al. (2015) J Infect Dis "Targeting Filarial Abl-like Kinases: Orally Available, Food and Drug Administration-Approved Tyrosine Kinase Inhibitors Are Microfilaricidal and Macrofilaricidal."

Nutman TB, O'Connell EM, Bennuru S, Steel C, Dolan MA

[J Infect Dis, 2015]

BACKGROUND: Elimination of onchocerciasis and lymphatic filariasis is targeted for 2020. Given the coincident Loa loa infections in Central Africa and the potential for drug resistance development, the need for new microfilaricides and macrofilaricides has never been greater. With the genomes of L. loa, Onchocerca volvulus, Wuchereria bancrofti, and Brugia malayi available, new drug targets have been identified. METHODS: The effects of the tyrosine kinase inhibitors imatinib, nilotinib, and dasatinib on B. malayi adult males, adult females, L3 larvae, and microfilariae were assessed using a wide dose range (0-100 M) in vitro. RESULTS: For microfilariae, median inhibitory concentrations (IC50 values) on day 6 were 6.06 M for imatinib, 3.72 M for dasatinib, and 81.35 M for nilotinib; for L3 larvae, 11.27 M, 13.64 M, and 70.98 M, respectively; for adult males, 41.6 M, 3.87 M, and 68.22 M, respectively; and for adult females, 42.89 M, 9.8 M, and >100 M, respectively. Three-dimensional modeling suggests how these tyrosine kinase inhibitors bind and inhibit filarial protein activity. CONCLUSIONS: Given the safety of imatinib in humans, plans are underway for pilot clinical trials to assess its efficacy in patients with filarial infections.

Lemire BD et al. (2009) Mech Ageing Dev "C. elegans longevity pathways converge to decrease mitochondrial membrane potential."

Behrendt M, Decorby A, Lemire BD, Gaskova D

[Mech Ageing Dev, 2009]

Energy production via oxidative phosphorylation generates a mitochondrial membrane potential (DeltaPsi(m)) across the inner membrane. In this work, we show that a lower DeltaPsi(m) is associated with increased lifespan in Caenorhabditis elegans. The long-lived mutants daf-2(e1370), age-1(hx546), clk-1(qm30), isp-1(qm150) and eat-2(ad465) all have a lower DeltaPsi(m) than wild type animals. The lower DeltaPsi(m) of daf-2(e1370) is daf-16 dependent, indicating that the insulin-like signaling pathway not only regulates lifespan but also mitochondrial energetics. RNA interference (RNAi) against 17 genes shown to extend lifespan also decrease DeltaPsi(m). Furthermore, lifespan can be significantly extended with the uncoupler carbonylcyanide-3-chlorophenylhydrazone (CCCP), which dissipates DeltaPsi(m). We conclude that longevity pathways converge on the mitochondria and lead to a decreased DeltaPsi(m). Our results are consistent with the 'uncoupling to survive' hypothesis, which states that dissipation of the DeltaPsi(m) will extend lifespan.

Seo J et al. (2005) Arch Environ Contam Toxicol "Biodegradation of the insecticide N,N-diethyl-m-toluamide by fungi: identification and toxicity of metabolites."

Kim SD, Cha CJ, Hur HG, Lee YG, Seo J, Ahn JH

[Arch Environ Contam Toxicol, 2005]

Fungi (Cunninghamella elegans ATCC 9245, Mucor ramannianus R-56, Aspergillus niger VKMF-1119, and Phanerochaete chrysosporium BKMF-1767) were tested to elucidate the biologic fate of the topical insect repellent N,N-diethyl-m-toluamide (DEET). The elution profile obtained from analysis by high-pressure liquid chromatography equipped with a reverse-phase C-18 column, showed that three peaks occurred after incubation of C. elegans, with which 1 mM DEET was combined as a final concentration. The peaks were not detected in the control experiments with either DEET alone or tested fungus alone. The metabolites produced by C. elegans exhibited a molecular mass of 207 with a fragment ion (m/z) at 135, a molecular mass of 179 with an m/z at 135, and a molecular mass of 163 with an m/z at 119, all of which correspond to N,N-diethyl-m-toluamide-N-oxide, N-ethyl-m-toluamide-N-oxide, and N-ethyl-m-toluamide, respectively. M. ramannianus R-56 also produced N, N-diethyl-m-toluamide-N-oxide and N-ethyl-m-toluamide but did not produce N-ethyl-m-toluamide-N-oxide. For the biologic toxicity test with DEET and its metabolites, the freshwater zooplankton Daphnia magna was used. The biologic sensitivity in decreasing order was DEET > N-ethyl-m-toluamide > N,N-diethyl-m-toluamide-N-oxide. Although DEET and its fungal metabolites showed relatively low mortality compared with other insecticides, the toxicity was increased at longer exposure periods. These are the first reports of the metabolism of DEET by fungi and of the biologic toxicity of DEET and its fungal metabolites to the freshwater zooplankton D. magna.

Foehr ML et al. (2008) Dev Biol "Dorsoventral patterning of the C. elegans postembryonic mesoderm requires both LIN-12/Notch and TGFbeta signaling."

Liu J, Foehr ML

[Dev Biol, 2008]

The C. elegans postembryonic mesodermal lineage arises from a single cell M, which generates distinct dorsal and ventral cell types. We have previously shown that mutations in the Schnurri homolog sma-9 cause ventralization of the M lineage and that wild-type SMA-9 antagonizes the Sma/Mab TGFbeta pathway to promote dorsal M lineage fates [Foehr, M.L., Lindy, A.S., Fairbank, R.C., Amin, N.M., Xu, M., Yanowitz, J., Fire, A.Z., Liu, J., 2006. An antagonistic role for the C. elegans Schnurri homolog SMA-9 in modulating TGFbeta signaling during mesodermal patterning. Development 133, 2887-2896]. Interestingly, loss-of-function mutations in the Notch receptor lin-12 cause dorsalization of the M lineage [Greenwald, I.S., Sternberg, P.W., Horvitz, H.R., 1983. The lin-12 locus specifies cell fates in Caenorhabditis elegans. Cell 34, 435-444]. We have found that although LIN-12 protein is present in both the dorsal and ventral M lineage cells, its ligands LAG-2 and APX-1 are asymmetrically localized in cells adjacent to ventral M-derived cells, and may function redundantly in promoting ventral M lineage fates. To investigate how LIN-12/Notch signaling interacts with SMA-9 and Sma/Mab TGFbeta signaling in regulating M lineage patterning, we generated double and triple mutant combinations among lin-12, sma-9 and dbl-1 (the ligand for the Sma/Mab TGFbeta pathway) and examined their M lineage phenotypes. Our results suggest that the LIN-12/Notch pathway and the Sma/Mab TGFbeta pathway function independently in regulating dorsoventral patterning of the M lineage, with LIN-12/Notch required for ventral M lineage fates, and SMA-9 antagonism of TGFbeta signaling required for dorsal M lineage fates. Our work provides a model for how combined Notch and TGFbeta signaling regulates the developmental potential of two equipotent cells along the dorsoventral axis.

Raimondi S et al. (2023) FASEB Bioadv "Human wild-type and D76N β2-microglobulin variants are significant proteotoxic and metabolic stressors for transgenic C. elegans."

Ruoppolo M, Faravelli G, Marchese L, Lavatelli F, Mangione PP, Giorgetti S, Nocerino P, Mimmi MC, Mondani V, Canetti D, Bellotti V, Caterino M, Baruffaldi A, Raimondi S, Verona G

[FASEB Bioadv, 2023]

&#x3b2;₂-microglobulin (&#x3b2;₂-m) is a plasma protein derived from physiological shedding of the class I major histocompatibility complex (MHCI), causing human systemic amyloidosis either due to persistently high concentrations of the wild-type (WT) protein in hemodialyzed patients, or in presence of mutations, such as D76N &#x3b2;₂-m, which favor protein deposition in the adulthood, despite normal plasma levels. Here we describe a new transgenic Caenorhabditis elegans (<i>C. elegans</i>) strain expressing human WT &#x3b2;₂-m at high concentrations, mimicking the condition that underlies dialysis-related amyloidosis (DRA) and we compare it to a previously established strain expressing the highly amyloidogenic D76N &#x3b2;₂-m at lower concentrations. Both strains exhibit behavioral defects, the severity of which correlates with &#x3b2;₂-m levels rather than with the presence of mutations, being more pronounced in WT &#x3b2;₂-m worms. &#x3b2;₂-m expression also has a deep impact on the nematodes' proteomic and metabolic profiles. Most significantly affected processes include protein degradation and stress response, amino acids metabolism, and bioenergetics. Molecular alterations are more pronounced in worms expressing WT &#x3b2;₂-m at high concentration compared to D76N &#x3b2;₂-m worms. Altogether, these data show that &#x3b2;₂-m is a proteotoxic protein in&#xa0;vivo also in its wild-type form, and that concentration plays a key role in modulating pathogenicity. Our transgenic nematodes recapitulate the distinctive features subtending DRA compared to hereditary &#x3b2;₂-m amyloidosis (high levels of non-mutated &#x3b2;₂-m vs. normal levels of variant &#x3b2;₂-m) and provide important clues on the molecular bases of these human diseases.

Walker NR et al. (1998) J Nematol "Interaction Between Meloidogyne incognita and Thielaviopsis basicola on Cotton (Gossypium hirsutum)."

Walker NR, Kirkpatrick TL, Rothrock CS

[J Nematol, 1998]

The effects of Meloidogyne incognita and Thielaviopsis basicola on the growth of cotton (Gossypium hirsutum) and the effects of T. basicola on M. incognita populations were evaluated in a 2-year study. Microplots were infested with M. incognita, T. basicola, or a combination of M. incognita and T. basicola. Uninfested plots served as controls both years. Seedling survival was decreased by the M. incognita + T. basicola treatment compared to the control. Meloidogyne incognita alone and M. incognita + T. basicola reduced plant height-to-node ratio for seedlings in both years. Seed cotton yield was reduced, and the length of time required for boll maturation was lengthened by M. incognita + T. basicola in 1994 and M. incognita both alone and with T. basicola in 1995. Position of the first sympodial node on the main stem was increased by M. incognita in both years and was higher for plants treated with M. incognita + T. basicola in 1995 in comparison to the control. The number of sympodial branches with bolls in the first and second fruiting position and the percentage of bolls retained in the second position were reduced both years by M. incognita + T. basicola compared to either the control or T. basicola alone. Orthogonal contrasts indicated that effects on height-to-node ratio, number of days to first cracked boll, and yield were significantly different for combined pathogen inoculations than with either pathogen alone. Meloidogyne incognita eggs at harvest were reduced by T. basicola in 1994 and 1995 compared to M. incognita alone. The study demonstrated a significant interaction between M. incognita and T. basicola on cotton that impacted the survival and development of cotton and the reproduction of M. incognita on cotton.

Meyer SL et al. (2005) Mycologia "Morphological variability and molecular phylogeny of the nematophagous fungus Monacrosporium drechsleri."

Meyer SL, Carta LK, Rehner SA

[Mycologia, 2005]

An isolate of the nematode-trapping fungus Monacrosporium drechsleri was collected from cultures of the root-knot nematode Meloidogyne arenaria that had been maintained on tomato roots in greenhouse pots in Beltsville, Maryland. The plant-parasitic nematodes Heterodera glycines, Meloidogyne incognita and Pratylenchus zeae and the free-living nematodes Caenorhabditis elegans and Panagrellus redivivus were placed on colonies of M. drechsleri grown in Petri dishes to study ability of the isolate to trap various nematode hosts. None of the nematodes placed near adhesive knobs were motile within 1 d. To determine where M. drechsleri fits within the existing phylogeny of nematode-trapping fungi, the ITS1-ITS2 regions of rDNA and the nuclear gene EF1-alpha were sequenced for the new isolate of M. drechsleri, for the species M. parvicolle and M. lysipagum, and for an isolate of M. ellipsosporum distinct from the one listed in GenBank. Parsimony trees were constructed showing the closest molecular relative of M. drechsleri to be the newly sequenced isolate of M. ellipsosporum; the latter had a highly divergent sequence from the sequence recorded in GenBank for a different isolate of M. ellipsosporum. Unique, consistent and discrete morphological characters are absent in these related taxa, so an independent molecular character should be considered essential for their accurate identification.

DiBartolomeis SM et al. (2002) Mol Genet Genomics "Molecular analysis of the Drosophila miniature-dusky ( m-dy) gene complex: m-dy mRNAs encode transmembrane proteins with similarity to C. elegans cuticulin."

Jackson FR, Akten B, Roberts MA, DiBartolomeis SM, Genova G

[Mol Genet Genomics, 2002]

Mutations in the Drosophila miniature-dusky ( m-dy) gene complex were first reported by Morgan and Bridges about 90 years ago. m-dy mutants have abnormally small wings, a phenotype attributed to a cell-autonomous reduction in the size of the epidermal cells comprising the differentiated wing. Using a molecular genetic approach, we have characterized the m-dy chromosomal interval and identified a pair of adjacent transcription units corresponding to m and dy. A dy mutant known as dy (And) has a single base substitution within the protein-coding region that is predicted to result in an amber stop codon and premature translational termination. We show that dy mRNA is expressed at two discrete periods during the life cycle - one during embryonic development and early larval instars, the second during adult development, coincident with wing differentiation. In agreement with the phenotypic similarity of m and dy mutants, sequence comparisons reveal a similarity between the predicted MINIATURE and DUSKY proteins, and indicate that the m and dy genes are members of a larger Drosophila gene family. Both m and dy, as well as other members of this superfamily, are predicted to encode transmembrane proteins with similarity to C. elegans cuticle proteins known as cuticulins. We postulate that m, dy and other members of this protein superfamily function as structural components of the Drosophila cuticulin layer. Such a role for m and dy products in wing differentiation is sufficient to explain the morphological phenotypes associated with m-dy mutants.

Wierzchowski J et al. (2007) Nucleosides Nucleotides Nucleic Acids "Kinetics of C. elegans DcpS cap hydrolysis studied by fluorescence spectroscopy."

Davis RE, Jankowska-Anyszka M, Pietrzak M, Wierzchowski J, Darzynkiewicz E, Jemielity J, Kalek M, Bojarska E, Stepinski J

[Nucleosides Nucleotides Nucleic Acids, 2007]

DcpS (scavenger decapping enzyme) from nematode C. elegans readily hydrolyzes both monomethyl- and trimethylguanosine cap analogues. The reaction was followed fluorimetrically. The marked increase of fluorescence intensity after the cleavage of pyrophosphate bond in dinucleotides was used to determine K(m) and V(max)values. Kinetic parameters were similar for both classes of substrates and only slightly dependent on pH. The hydrolysis was strongly inhibited by methylene cap analogues (m(7)Gp(CH(2))ppG and m(7)Gpp(CH(2))pG) and less potently by ARCA (m(7,3'' O)GpppG).