Henrietta Ngangyung | Walden University (original) (raw)

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Papers by Henrietta Ngangyung

Molecular & cellular proteomics : MCP, Aug 25, 2016

In spite of 40 years of control efforts, onchocerciasis (river blindness) remains one of the most... more In spite of 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The aetiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilise the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4,260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body ...

The essential natural resources such as arable soils, the household and pastoral water and the ve... more The essential natural resources such as arable soils, the household and pastoral water and the vegetation of the Vina Division are rapidly deteriorating these last recent years. The lowering fertility level of farm lands, the degradation of vegetation on pasture lands, and the insufiancy of household water and for animals are the observed indicators. Inded it was for this work to determine wether the actual ownership modalities or management practices are causes of the degradation or natural parameters could be associated to them?. Four localities included; Dibi, Mbang-Mboum, Mbe and Tourningal hav been choosen as study sites for investigation. From the study of the Adamawa Regional and Vina Divisional pedologic maps, from the observation and data collected from the field work, the soils of the four villages can be put into two major groups; ferruginous for Mbang-Mboum and Mbe, ferralitic for Dibi and Tourningal. Naturally these soils are poor in nutrient and were compacted by the p...

PLOS Pathogens

Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected... more Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected tropical disease mostly affecting sub-Saharan Africa and is responsible for >1.3 million years lived with disability. Current control relies almost entirely on ivermectin, which suppresses symptoms caused by the first-stage larvae (microfilariae) but does not kill the long-lived adults. Here, we evaluated emodepside, a semi-synthetic cyclooctadepsipeptide registered for deworming applications in companion animals, for activity against adult filariae (i.e., as a macrofilaricide). We demonstrate the equivalence of emodepside activity on SLO-1 potassium channels in Onchocerca volvulus and Onchocerca ochengi, its sister species from cattle. Evaluation of emodepside in cattle as single or 7-day treatments at two doses (0.15 and 0.75 mg/kg) revealed rapid activity against microfilariae, prolonged suppression of female worm fecundity, and macrofilaricidal effects by 18 months post treatment...

Journal of Environment and Ecology, 2011

Parasites & vectors, Jan 27, 2015

BackgroundmicroRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, c... more BackgroundmicroRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, cell-free form in mammalian body fluids. Specific miRNAs are secreted by parasitic nematodes in exosomes and have been detected in the serum of murine and dog hosts infected with the filarial nematodes Litomosoides sigmodontis and Dirofilaria immitis, respectively. Here we identify extracellular, parasite-derived small RNAs associated with Onchocerca species infecting cattle and humans.MethodsSmall RNA libraries were prepared from total RNA extracted from the nodule fluid of cattle infected with Onchocerca ochengi as well as serum and plasma from humans infected with Onchocerca volvulus in Cameroon and Ghana. Parasite-derived miRNAs were identified based on the criteria that sequences unambiguously map to hairpin structures in Onchocerca genomes, do not align to the human genome and are not present in European control serum.ResultsA total of 62 mature miRNAs from 52 distinct pre-miRNA can...

Molecular & cellular proteomics : MCP, Aug 25, 2016

In spite of 40 years of control efforts, onchocerciasis (river blindness) remains one of the most... more In spite of 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The aetiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilise the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4,260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body ...

The essential natural resources such as arable soils, the household and pastoral water and the ve... more The essential natural resources such as arable soils, the household and pastoral water and the vegetation of the Vina Division are rapidly deteriorating these last recent years. The lowering fertility level of farm lands, the degradation of vegetation on pasture lands, and the insufiancy of household water and for animals are the observed indicators. Inded it was for this work to determine wether the actual ownership modalities or management practices are causes of the degradation or natural parameters could be associated to them?. Four localities included; Dibi, Mbang-Mboum, Mbe and Tourningal hav been choosen as study sites for investigation. From the study of the Adamawa Regional and Vina Divisional pedologic maps, from the observation and data collected from the field work, the soils of the four villages can be put into two major groups; ferruginous for Mbang-Mboum and Mbe, ferralitic for Dibi and Tourningal. Naturally these soils are poor in nutrient and were compacted by the p...

PLOS Pathogens

Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected... more Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected tropical disease mostly affecting sub-Saharan Africa and is responsible for >1.3 million years lived with disability. Current control relies almost entirely on ivermectin, which suppresses symptoms caused by the first-stage larvae (microfilariae) but does not kill the long-lived adults. Here, we evaluated emodepside, a semi-synthetic cyclooctadepsipeptide registered for deworming applications in companion animals, for activity against adult filariae (i.e., as a macrofilaricide). We demonstrate the equivalence of emodepside activity on SLO-1 potassium channels in Onchocerca volvulus and Onchocerca ochengi, its sister species from cattle. Evaluation of emodepside in cattle as single or 7-day treatments at two doses (0.15 and 0.75 mg/kg) revealed rapid activity against microfilariae, prolonged suppression of female worm fecundity, and macrofilaricidal effects by 18 months post treatment...

Journal of Environment and Ecology, 2011

Parasites & vectors, Jan 27, 2015

BackgroundmicroRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, c... more BackgroundmicroRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, cell-free form in mammalian body fluids. Specific miRNAs are secreted by parasitic nematodes in exosomes and have been detected in the serum of murine and dog hosts infected with the filarial nematodes Litomosoides sigmodontis and Dirofilaria immitis, respectively. Here we identify extracellular, parasite-derived small RNAs associated with Onchocerca species infecting cattle and humans.MethodsSmall RNA libraries were prepared from total RNA extracted from the nodule fluid of cattle infected with Onchocerca ochengi as well as serum and plasma from humans infected with Onchocerca volvulus in Cameroon and Ghana. Parasite-derived miRNAs were identified based on the criteria that sequences unambiguously map to hairpin structures in Onchocerca genomes, do not align to the human genome and are not present in European control serum.ResultsA total of 62 mature miRNAs from 52 distinct pre-miRNA can...