Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nematode spermatozoa, unlike their mammalian counterparts, are nonflagellated crawling cells. The pseudopod of these cells contains the major sperm protein (MSP) which comprises more than 15% of the protein in the sperm. MSP is presumed to function as a cytoskeletal element involved in motility. An Ascaris MSP cDNA sequence was used as a probe to identify and isolate Onchocerca volvulus MSP clones from a lambda gt11 genomic library. Two clones, OVGS-1 (765 bp) and OVGS-2 (1765 bp), were characterized by restriction endonuclease mapping and sequence analysis. Both genomic clones contain MSP protein coding regions of 99 and 282 bp separated by an intervening sequence of 153 bp. The genes OVGS-1 and OVGS-2 are 95% similar in nucleotide sequence in the protein coding regions, but only 79% similar in their intron sequences. A number of potential regulatory sequences in the flanking regions and at the exon/intron junctions of the O. volvulus MSP genes are in good agreement with consensus sequences in other eukaryotic cells. The nucleotide sequence of the O. volvulus MSP genes were over 80% similar to the Ascaris MSP cDNA sequence and 79% similar to the Caenorhabditis MSP-3 cDNA. The predicted amino acid sequence of the O. volvulus MSPs were 96% similar to each other, 90-91% similar to Ascaris MSP and 81-82% similar to Caenorhabditis MSP-3. These results offer evidence that the MSP sequences have been highly conserved throughout nematode evolution but are variable in their genomic organization and the presence of introns.
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PMID:Major sperm protein genes from Onchocerca volvulus. 277 Jul 87

During chemotherapy trials in hyperendemic onchocerciasis areas in West Africa 15 adult nodule carriers in Liberia and 24 patients in Mali received single doses of ivermectin (150 or 200 micrograms/kg). Nodules were extirpated two, six and ten months after therapy and examined histologically. No macrofilaricidal effect of ivermectin was observed. Two months after therapy, in 93% of all female worms with intrauterine stretched microfilariae nearly all microfilariae were degenerated. The percentage was lower after ten months but still significantly higher than in untreated control groups. Ivermectin did not cause degeneration of the intrauterine coiled microfilariae. But the percentage of the female worms with coiled microfilariae was significantly lower two and ten months after therapy than that in the placebo or untreated control groups. Correspondingly, the percentage of nodules with intact microfilariae in the nodule tissue was also significantly lower throughout the examination period than that of the untreated control groups. There was not observed any effect on the spermatogenesis and spermatozoa were found frequently in the uteri of female worms. Using the method of histology, the long lasting inhibitory effect of a single dose of ivermectin on the intrauterine production of microfilariae could clearly be demonstrated. This proves the value of histology for the assessment of drug effects on adult O. volvulus.
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PMID:Histological examination of onchocercomata after therapy with ivermectin. 317 72

A simple technique for the identification of the different spermatogenetic stages of Onchocerca volvulus is described. It is practicable for large-scale examinations in the field. The reproductivity of male worm populations can be assessed and directly correlated with the corresponding female worm populations. The activity of male filariae decreases with the increasing age of the worm population. Only few male worms transmit spermatozoa during mating, but spermatogenesis is continous also in very old male individuals. These old male filariae store high numbers of spermatozoa and cease their migration between the nodules.
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PMID:Investigations of enzymatically isolated male Onchocerca volvulus: qualitative and quantitative aspects of spermatogenesis. 322 43

Glutathione S-transferases (GSTs) constitute a major detoxification mechanism in helminth organisms and are regarded vaccine candidates against helminth infections. Onchocerca volvulus glutathione-binding proteins were purified from the aqueous soluble fraction of homogenised adult females by affinity chromatography on glutathione-agarose. The eluted proteins had a specific GST activity of 1.6 mumol min-1 mg-1. Immunohistochemical studies localised these antigens in the hypodermis, the wall of the seminal receptacle and spermatozoa of adult worms. A lambda gt11 clone was isolated from an expression library of O. volvulus by immunoscreening. Sequence analysis revealed that it encoded a pi-class GST with 60% identity with Caenorhabditis elegans and up to 45% identity with mammalian pi-class GSTs. Antibodies affinity selected with recombinant GST demonstrated cross-reactivity between Litomosoides sigmodontis and O. volvulus GSTs.
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PMID:Molecular characterisation and localisation of an Onchocerca volvulus pi-class glutathione S-transferase. 798 70

Wolbachia, a genus of endosymbiotic bacteria of filarial worms, represent novel targets for anti-filarial therapy. The efficacy of compounds against Wolbachia has been evaluated using antiserum raised against the 60 kDa heat shock protein (HSP60) which binds specifically to this protein in both Wolbachia and mitochondria. It has been shown that Wolbachia stains (using such specific probes) stronger than the mitochondria in untreated Onchocerca volvulus, whereas after the depletion of Wolbachia (with drugs) staining of the mitochondria is increased. Herein, immunogold electron microscopy showed that specific anti-HSP60 serum specifically labelled Wolbachia and filarial mitochondria, and that both have distinct localization patterns, thus allowing them to be differentiated. Immunohistochemistry of O. volvulus showed that HSP60 staining is increased in the mitochondria after Wolbachia depletion in the hypodermis, epithelia, muscles, oocytes, embryos, and developing spermatozoa. This could have been the result of the antiserum preferentially binding to the Wolbachia when they are present or due to increased expression of the protein in the absence of the bacteria. To address this, mRNA levels of filarial hsp60 in O. volvulus were measured. After the depletion of Wolbachia, the transcription of hsp60 was significantly greater (7.7 fold) compared with untreated worms. We hypothesize that the increased expression of HSP60 in the absence of Wolbachia is due to a disruption of the homeostasis of the endosymbiosis.
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PMID:The mitochondrial heat shock protein 60 (HSP60) is up-regulated in Onchocerca volvulus after the depletion of Wolbachia. 1820 85