Karam M et al. (1987) Acta Trop "Population dynamics of Onchocerca volvulus after 7 to 8 years of vector control in West Africa."

Karam M, Schulz-Key H, Remme J

[Acta Trop, 1987]

In an attempt to describe the changing population dynamics of Onchocerca volvulus during a period of vector control, nodulectomies were undertaken in 256 patients from ten villages in the Onchocerciasis Control Programme (OCP) and in 74 patients from two villages in an area with ongoing transmission. A total of 1198 nodules were excised and 4350 adult worms were isolated and examined for viability and productivity. In the OCP villages, the worm population is ageing and dying without replacement by new generations of parasites and various findings signal a breakdown of the worm population after about 12 years interruption of transmission. The sexual activity of the worms was significantly reduced. A Productivity Index was developed to measure the microfilariae production at the nodule level. The reduction in this index for the OCP villages correlates closely with the decline over the control period in the community microfilarial loads in the skin. The results show that it is not only the longevity of the parasite which will determine the duration of vector control, but that the reduced productivity of the ageing parasite population is of equal importance.

Schulz-Key H et al. (1984) Trans R Soc Trop Med Hyg "Quantitative assessment of microfilariae and adults of Onchocerca volvulus in ethanol-fixed biopsies and nodules."

Schulz-Key H, Karam M

[Trans R Soc Trop Med Hyg, 1984]

Ethanol-fixed Onchocerca nodules and skin snips were successfully digested with collagenase to assess the parasite load. The importance of this technique for investigations in the field is discussed.

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.

Bradley JE et al. (1993) Parasitology "The effects of vector control on the antibody response to antigens of Onchocerca volvulus."

Bradley JE, Gillespie AJ, Karam M, Trenholme KR

[Parasitology, 1993]

The effects of exposure to infective larvae on the antibody response to a cocktail of specific recombinant antigens of Onchocerca volvulus and to a worm extract were evaluated by comparing the responses of individuals from a vector controlled area with those from an area of continuing transmission by ELISA. Individuals from the vector controlled areas were found to have reduced responses to both antigen preparations. A microfilerdermic (mf-) individuals from the area of vector control exhibited significantly lower total and subclass IgG responses to the worm extract. In contrast, the responses to the cocktail of specific recombinants were significantly reduced in individuals from the area of vector control who were still microfilerdermia positive (mf+). The distribution of IgG subclass specific responses was similar to both antigen preparations, both dominated by the IgG4 and IgG1 subclasses. IgG1 responses to the worm extract remained elevated in the vector controlled individuals but IgG4 was significantly reduced in the mf- individuals. Both subclasses reflected the total IgG response to the cocktail of recombinants and were significantly reduced in individuals from the vector controlled area, when compared to individuals from the hyperendemic area. IgG1 responses to the cocktail of recombinants are significantly lower than IgG4 in all individuals and virtually absent in individuals from the vector-controlled area. Measuring total IgG and IgG4 is more sensitive than IgG1 in detecting infection, 100 or 97% respectively, but they remain elevated in the individuals from the vector controlled areas even after 8-10 years interruption of transmission. These results have important implications for the serological monitoring of control programmes in individuals who have previously been infected.

Shah JS et al. (1987) Am J Trop Med Hyg "Characterization of an Onchocerca-specific DNA clone from Onchocerca volvulus."

Piessens WF, Karam M, Shah JS, Wirth DF

[Am J Trop Med Hyg, 1987]

A genomic library of a savanna isolate of Onchocerca volvulus was screened to detect recombinant plasmids containing highly repeated DNA sequences of this parasite. Four recombinant plasmids were identified which hybridized specifically to Onchocerca DNA, but not to DNA from humans, black flies, Brugia malayi, B. pahangi, or Wuchereria bancrofti. The recombinant plasmids had a low level of homology to Dirofilaria immitis. All recombinant plasmids contain related DNA sequences based on Southern hybridization analysis. Sequences related to these recombinant plasmids are present in different geographic isolates of O. volvulus and O. ochengi, an animal parasite. Two of the recombinant plasmids contain sequences also found in O. lienalis. One recombinant plasmid, puOvs3, has been characterized in detail, including DNA sequence determination. Radiolabeled puOvs3 is able to detect 100 pg of genomic DNA isolated from O. volvulus worms from both savanna and forest regions. It can differentiate O. volvulus from O. ochengi by Southern blot analysis.

Wood WB (1976) Worm Breeder's Gazette "maternal effects among ts zygote-defective (zyg) mutants."

Wood WB

[Worm Breeder's Gazette, 1976]

We have studied maternal effects in 23 zyg ts mutants to estimate the times of expression of genes whose products are required in embryogenesis. We have used the following three tests, called arbitrarily A, B, and C. A test: Heterozygous (m/+) L4's are shifted to 25 C and allowed to self-fertilize. If 100% of their eggs yield larvae (25% of which express the mutant phenotype as adults), then the mutant is scored as maternal (M). If 25% of the F1 eggs fail to hatch, then the mutant is scored as non-maternal (N). An M result indicates that expression of the + allele in the parent allows m/m zygotes to hatch and grow to adulthood. A result of N indicates the opposite: that the + allele must be expressed in the zygote for hatching to occur. Out of 23 zyg mutants tested, 3 were scored N and 20 were scored M in the A test. Therefore, for most of the genes defined by these mutants, expression in the parent is sufficient for zygote survival, even if the gene is not expressed in the zygote. B test: Homozygous (m/m) hermaphrodites reared at 25 C are mated with N2 (+/+) males. If eggs fail to hatch at 25 C, but mated hermaphrodites shifted to 16 C produce cross progeny to give proof of mating, then the mutant is scored M. If cross progeny appear in the 25 C mating, then the mutant is scored N. An M result indicates that expression of the + allele in the zygote is not sufficient to allow m/+ progeny of an m/m hermaphrodite to survive. Conversely an N result indicates either that zygotic expression of the + allele is sufficient for survival, or that a sperm function or factor needed for early embryogenesis can be supplied paternally (see C test below). Out of the 23 zyg mutants tested, 11 were scored M and 12 were scored N. The combined results of A and B tests and their simplest interpretation are as follows. Ten mutants are M,M; the genes defined by these mutants must be expressed in the hermaphrodite parent for the zygote to survive. Ten mutants are M,N; these genes can be expressed either in the parent or in the zygote. Two mutants are N,N; these genes must be expressed in the zygote. One mutant is N,M; this gene must be expressed both in the maternal parent and in the zygote. C test: Homozygous (m/m) hermaphrodites reared at 25 C are mated with heterozygous (m/+) males. If rescue by a +/+ male in the B test depends on the + allele, then only half the cross progeny zygotes of a C test mating (m/+ male x m/m hermaphrodite) should survive. However, if rescue depends on a function or cytoplasmic component from the male sperm, then all the cross progeny zygotes in a C test should survive. Of the 10 M,N mutants, 6 have been C tested; one exhibited paternal rescue independent of the + allele. The A and B tests also were carried out on 16 mutants that arrest before the L3 molt (acc mutants). In the A test on 2 of these mutants, all m/m progeny of m/+ parents grew to adulthood at 25 C. Therefore, parental contributions are sufficient to overcome a progeny mutational block as late as the L2 stage. All 16 acc mutants scored N in the B test.

Ali Khan L et al. (1994) Worm Breeder's Gazette "cej-1 Encodes a Novel Protein With Poly-Threonine Motif"

Siddiqui SS, Fukushige T, Ali Khan L, Tsukita Sh, Tabish M, Itoh M

[Worm Breeder's Gazette, 1994]

cej-1 Encodes a Novel Protein with Poly-Threonine Motif M. L. A. Khanl, M. Tabish, T. Fukushigel1 S. Tsukita2, M. Itoh , Sh. Tsukita , and S. S. Siddiqui. (1): Lab. of Molecular Biology, Dept of Ecological Engg. Toyohashi Univ. Technology, Toyohashi 441, and (2). National Institute for Physiological Sciences, Okazaki 444, Japan.

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.