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PubMed1995

The effects of the nematode peptide, KHEYLRFamide (AF2), on the somatic musculature of the parasitic nematode Ascaris suum.

AF2 is an endogenous RFamide-like peptide from the parasitic nematode Ascaris suum. The potent stimulatory effects of this peptide on the somatic musculature of Ascaris strongly suggest that it may have an important role in the motornervous system. Here we have investigated the possibility that AF2 may elicit a stimulatory action on Ascaris muscle by potentiating the actions of the excitatory cholinergic motonervous system either pre-synaptically, post-synaptically or both. In in vitro pharmacological experiments AF2 produced a dose-dependent increase in the frequency and amplitude of spontaneous contractions of Ascaris muscle strip which lasted for more than 1 h after a 3 min application of AF2 (10 nM-10 microM; N = 7). In addition, AF2 (100 nM) potentiated the contraction elicited by ACh by 43 +/- 9% (P < 0.01; N = 8). In electrophysiological recordings from muscle cells, AF2 (10-100 nM; N = 10) potentiated the amplitude of EJPs (excitatory junction potentials). For 100 nM AF2, the potentiation of the EJP was 218 +/- 48% (N = 7; P < 0.01). This effect reversed after a wash of 10 min. AF2 did not potentiate the depolarization of the muscle cell elicited by bath applied ACh. These latter two observations are consistent with a presynpatic action of AF2. AF2 (10-100 nM) generated spontaneous muscle cell action potentials in previously quiescent cells. This effect took more than 1 h to wash out. These observations are discussed in terms of the paralysis of Ascaris that is elicited by AF2.

Acetylcholine↗

PubMed2000

Origin of the anomalous Fe-CO stretching mode in the CO complex of Ascaris hemoglobin.

We report an unusually high frequency (543 cm(-)(1)) for an Fe-CO stretching mode in the CO complex of Ascaris suum hemoglobin as compared to vertebrate hemoglobins in which the frequency of the Fe-CO mode is much lower. A second Fe-CO stretching mode in Ascaris hemoglobin is observed at 515 cm(-1). We propose that these two Fe-CO stretching modes arise from two protein conformers corresponding to interactions of the heme-bound CO with the B10-tyrosine or the E7-glutamine residues. This postulate is supported by spectra from the B10-Tyr --> Phe mutant in which the 543 cm(-1) line is absent. Thus, a strong polar interaction, such as hydrogen bonding, of the CO with the distal B10 tyrosine residue is the dominant factor that causes this anomalously high frequency. Strong hydrogen bonding between O(2) and distal residues in the oxy complex of Ascaris hemoglobin has been shown to result in a rigid structure, rendering an extremely low oxygen off rate [Gibson, Q. H., and Smith, M. H. (1965) Proc. R. Soc. London B 163, 206-214]. In contrast, the CO off rate in Ascaris hemoglobin is very similar to that in sperm whale myoglobin. The high CO off rate relative to that of O(2) in Ascaris hemoglobin is attributed to a rapid equilibrium between the two conformations of the protein in the CO adduct, with the off rate being determined by the conformer with the higher rate.

Animals↗

PubMed2005

Inactivation of Ascaris suum eggs by ammonia.

Uncharged ammonia is known to cause inactivation of a number of wastewater pathogens, but its effect on Ascaris eggs has never been isolated or quantified. The objectives of this research were to determine the conditions under which ammonia inactivates eggs of the swine Ascaris species, Ascaris suum, and to quantify the impact of ammonia on the U.S. EPA's requirements for alkaline treatment to produce Class A sludge. Eggs were incubated in controlled, laboratory solutions such that the effects of ammonia concentration and speciation, pH, and temperature could be separated. With a 24-h incubation, the inactivation at all pH levels (range 7-11) was not statistically different in the absence of ammonia. The presence of ammonia (0-1000 ppm as N) significantly increased Ascaris egg inactivation at pH 9 and 11, and the ovicidal effect was directly related to the concentration of the uncharged NH3 species. Increasing temperatures (32-52 degrees C) caused increased inactivation at all pH levels and ammonia concentrations. The current EPA treatment requirements to produce Class A biosolids by alkaline treatment have temperature, pH, and time requirements, but do not account for the effectof differences in ammonia concentration on inactivation. To illustrate the potential savings in temperature and pH that could be achieved when accounting for ammonia inactivation, the combinations of ammonia concentration, temperature, and pH neededto achieve 99% inactivation after 72 h were determined. The presence of ammonia at concentrations encountered in sludges and feces (up to 8000 ppm as N) allowed for 99% egg inactivation to be achieved at temperatures up to 14 degrees C lower than ammonia-free controls. Thus, environmentally relevant concentrations of ammonia may significantly increase the rate of Ascaris egg inactivation during alkaline stabilization.

Ammonia↗

PubMed2005

Cecropin P1 and novel nematode cecropins: a bacteria-inducible antimicrobial peptide family in the nematode Ascaris suum.

Cecropin P1 was first identified as a mammalian antimicrobial peptide isolated from the pig intestine. Much research aimed at characterizing this peptide has been reported. Recently, the workers who discovered the peptide corrected their original conclusion, and confirmed that this peptide originates in fact from the pig intestinal parasitic nematode, Ascaris suum. In the present study, we carried out a semi-exhaustive search for bacteria-inducible transcripts in A. suum by the cDNA subtraction method. The transcripts encoding cecropin P1 and novel Ascaris cecropins, designated cecropins P2, P3 and P4, were found to be positively induced factors. Chemically synthesized Ascaris cecropins were bactericidal against a wide range of microbes, i.e. Gram-positive (Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus) and Gram-negative (Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens and Esherichia coli) bacteria, and were weakly but detectably active against yeasts (Saccharomyces cerevisiae and Candida albicans). Cecropin P1-like sequences were also detected at least in two other species (Ascaris lumbricoides and Toxocara canis) of the Ascarididae. All Ascaris cecropin precursors contain an acidic pro-region connected by a tetra-basic cleavage site at the C-terminus. Such an acidic pro-region is also reported to be present in the tunicate cecropin-type antimicrobial peptide styelin. On the basis of the evolutionary position of nematodes and tunicates, the ancestral cecropin may have contained the acidic pro-region at the C-terminus.

Amino Acid Sequence↗

PubMed1994

Formation of two hydrogen bonds from the globin to the heme-linked oxygen molecule in Ascaris hemoglobin.

We have tried to find out why Ascaris hemoglobin has such an exceptionally high oxygen affinity (P50 approximately 0.004 mmHg; 1 mmHg = 133 Pa). Following Kloek et al., we have synthesized the N-terminal globin domain of Ascaris hemoglobin in Escherichia coli [Kloek, A. P., Yang, J., Mathews, F. S. & Goldberg, D. (1993) J. Biol. Chem. 268, 17669-17671]. Like Kloek et al., we found its oxygen affinity to be as high as that of native Ascaris hemoglobin. We thought that this high affinity might be due to the heme-bound oxygen molecule being stabilized by two hydrogen bonds from the globin instead of the usual one. Ascaris hemoglobin has a distal glutamine instead of the more usual histidine as one of the potential hydrogen bond donors. In addition, it contains a tyrosine at position 10 of B helix (B10) in place of the leucine generally found there in vertebrate myoglobins and hemoglobins. Following the discovery of Carver et al. that sperm whale myoglobin with the replacement of leucine B10 by phenylalanine has a raised oxygen affinity, we have replaced tyrosine B10 in the N-terminal domain of Ascaris hemoglobin by either leucine or phenylalanine [Carver, T. E., Brantley, R. E., Jr., Singleton, E. W., Arduini, R. M., Quillin, H. L., Phillips, G. N., Jr., & Olson, J. S. (1992) J. Biol. Chem. 267, 14443-14450]. Either of these replacements lowered the oxygen affinity about 100-fold, to the same level of that of human alpha-globin chains. These results are consistent with a hydrogen bond linking the tyrosine hydroxyl to the heme-linked oxygen, with a bond energy of 2.7 kcal/mol.

Allosteric Regulation↗

PubMed1997

Tachykinins contribute to the acute airways response to allergen in sheep actively sensitized to Ascaris suum.

Tachykinins, found in sensory nerves, have effects in the airways which suggest that they may contribute to the pathogenesis of asthma. We aimed to find evidence for tachykinin involvement in the immediate airway response to allergen in a sheep model of experimental asthma. Twenty-four sheep were actively sensitized to Ascaris suum, then challenged with nebulized Ascaris extract in a dose-response fashion. Change in lung resistance (RL) in response to challenge was measured. Responder sheep (those with an increase in RL of > or = 100% over baseline) that had reproducible responses over three challenges were identified (n = 4 sheep) and a PC100 (number of breaths of extract required to induce a 100% increase in RL) was determined. The effect of the neutral endopeptidase inhibitor phosphoramidon, the NK-1 receptor-specific antagonist CP 96, 345 and capsaicin desensitization on the RL response to Ascaris challenge was then assessed. Administration of phosphoramidon before Ascaris decreased the PC100 to 31 +/- 7% of the PC100 seen with Ascaris alone (P < 0.05), whereas CP 96,345 and capsaicin desensitization increased the PC100 to 285 +/- 41% and 555 +/- 93% respectively (P < 0.05 for both). These findings suggest that endogenous tachykinins are released in response to allergen challenge and that they contribute to the immediate increase in RL.

Allergens↗

PubMed2006

A real-time PCR method for quantifying viable ascaris eggs using the first internally transcribed spacer region of ribosomal DNA.

Worldwide, 1.4 billion people are infected with the intestinal worm Ascaris lumbricoides. As a result, Ascaris eggs are commonly found in wastewater and sludges. The current microscopy method for detecting viable Ascaris eggs is time- and labor-intensive. The goal of this study was to develop a real-time quantitative PCR (qPCR) method to determine the levels of total and viable Ascaris eggs in laboratory solutions using the first internally transcribed spacer (ITS-1) region of ribosomal DNA (rDNA) and rRNA. ITS-1 rDNA levels were proportional to Ascaris egg cell numbers, increasing as eggs developed from single cells to mature larvae and ultimately reaching a constant level per egg. Treatments causing >99% inactivation (high heat, moderate heat, ammonia, and UV) eliminated this increase in ITS-1 rDNA levels and caused decreases that were dependent on the treatment type. By taking advantage of this difference in ITS-1 rDNA level between viable, larvated eggs and inactivated, single-celled eggs, qPCR results were used to develop inactivation profiles for the different treatments. No statistical difference from the standard microscopy method was found in 75% of the samples (12 of 16). ITS-1 rRNA was detected only in samples containing viable eggs, but the levels were more variable than rDNA levels and ITS-1 rRNA could not be used for quantification. The detection limit of the rDNA-based method was approximately one larvated egg or 90 single-celled eggs; the detection limit for the rRNA-based method was several orders of magnitude higher. The rDNA qPCR method is promising for both research and regulatory applications.

Animals↗

PubMed1980

An investigation of the antigens of Ascaris lumbricoides using a radioimmunoassay and sera of naturally infected humans.

Of 5 humans from an Ascaris lumbricoides(var. suum)-endemic area who were positive for Ascaris infection (past or current) when examined by a radioallergosorbent test (RAST) for serum immunoglobulin E, only 1 contained detectable levels of Ascaris specific serum IgG antibodies. These antibodies were not detectable when the radioimmunoassay was replaced with a precipitin assay. There was a wide ringe of molecular weights and isoelectric points of antigens in Ascaris body fluid (ABF) which reacted with antibodies in this infected human. However, unlike the IgE-binding ABF antigens, the IgG-binding ABF antigens were particularly evident in one area of molecular weight and isoelectric point. This human also had IgA and IgM to Ascaris antigens whereas the others had barely detectable amounts.

Animals↗

PubMed2001

Contemporaneous and successive mixed Plasmodium falciparum and Plasmodium vivax infections are associated with Ascaris lumbricoides: an immunomodulating effect?

Following an investigation suggesting a protective role for Ascaris against cerebral malaria, possibly through immunomodulation, we examined whether Ascaris had any impact on mixed Plasmodium falciparum and Plasmodium vivax infections. We studied a cross section of 928 patient files between 1991 and 1999. Forty patients had contemporaneous mixed infections and 40 patients had P. falciparum infections, followed by P. vivax infections. There was a significant association between Ascaris infection and risk of having both contemporaneous or successive mixed P. falciparum and P. vivax infections (adjusted odds ratios respectively 6 [2-18] P = 0.001 and 3.6 [1.2-11.1] P = 0.02). There was a positive linear trend between the burden of Ascaris and the risk of mixed infections P < 0.0001. These results suggested the possibility that pre-existing Ascaris infection may increase tolerance of the host to different Plasmodium spp., thus facilitating their coexistence.

Animals↗

PubMed2003

Serum malondialdehyde level in patients infected with Ascaris lumbricoides.

AIM: The aim of the study was to investigate the changes of serum malondialdehyde level, i.e; the oxidative stress hypothesis in patients infected with Ascaris lumbricoides. METHODS: Serum malondialdehyde activity was measured in 43 patients who were positive for intestinal parasite of Ascaris lumbricoides. Scores were obtained for the positives and their age-and sex-matched 60 Ascaris lumbricoides negative healthy controls. RESULTS: The difference between malondialdehyde levels of patients infected with Ascaris lumbricoides and control group was statistically significant both for females (P<0.05) and for males (P<0.05). In the patient and control groups, no correlation was found between age and malondialdehyde levels (P>0.05) both in females and in males. In addition, no significant correlation could be found between malondialdehyde levels of both females and males for patients and control groups (P>0.05). CONCLUSION: Malondialdehyde levels clearly increase in patients infected with Ascaris lumbricoides.

Adolescent↗

PubMed1976

Demonstration and possible function of NADH:NAD+ transhydrogenase from ascaris muscle mitochondria.

Mitochondria from the muscle of Ascaris lumbricoides var. suis function anaerobically. NADH is generated in the intermembrane space as a consequence of the "malic" enzyme reaction. It has been suggested that this reducing equivalent in the form of hydride ion, would be translocated across the inner membrane in order to mediate ATP generation via the fumarate reductase reaction. In accord with this suggestion, intact Ascaris mitochondria showed appreciable NADH oxidase activity. Sonication resulted in an approximately 2-fold increase in NADH oxidase activity, whereas "malic" enzyme, fumarase, and NADH:NAD+ transhydrogenase activities increased approximately 7- to 14-fold, respectively. Phosphorylation capabilities and permeability toward pyridine nucleotides also indicated the intactness of the mitochondria. Ascaris mitochondria incubated anaerobically in the presence of fumarate, and [14C]NADH catalyzed a rapid reduction of the fumarate to succinate with the concomitant formation of equivalent quantities of extramitochondrial NAD+. However, very little isotope was recovered from the washed mitochondria, indicating the possibility of hydride ion translocation in the absence of nucleotide translocation. NADH:NAD+ transhydrogenase has been isolated from the muscle mitochondria of the intestinal nematode, Ascaris lumbricoides var. suis. The enzyme seems to have been solubilized from the mitochondrial membrane fraction by treatment with sodium deoxycholate followed by dialysis and subsequent adsorption by and elution from alumina C gamma. No NADPH:NAD+ transhydrogenase activity was detectable, making the Ascaris system unique over others reported. Activity was protected by L-cysteine, reduced glutathione and dithioerythritol, but strongly inhibited by low concentrations of p-chloromercuribenzoate or silver nitrate. The thionicotinamide derivative of NAD+ (thioNAD+) was employed to accept hydride ions from NADH in order to assay spectrophotometrically at 398 nm. Apparent Km values for thioNAD+ and NADH were 1 X 10(-4) M and 8 X 10(-6) M, respectively. That the physiological nucleotide, could act as hydride ion acceptor from NADH was indicated by the findings that NAD+ competitively inhibited the reduction of thioNAD+ when assayed at 398 nm. The additional finding of a noncompetitive inhibition between NAD+ and NADH suggested at least two binding sites on the enzyme, one for NADH and another common site for NAD+ and thioNAD+. More conclusive evidence indicating the participation of NAD+ as acceptor was obtained by incubation of the enzyme with NADH and [14C]NAD+ and demonstrating a rapid formation of [14C]NADH. These findings, in conjunction with those discussed above, suggest a physiological function of this enzyme in hydride ion translocation.

Aerobiosis↗

PubMed2000

Disturbances of mouse pregnancy after injection of Ascaris homogenate during early organogenesis.

Administration of the Ascaris tegumental homogenate (0.6-1.2 g of Ascaris proteins/kg/day) at a early stage of organogenesis (5-9 days of pregnancy) had a harmful effect upon the developing mouse fetuses. It has been found that injection of the homogenate did not delay or prevent implantation, but causes a high rate of intrauterine deaths. The Ascaris homogenate significantly decreased the number of live fetuses per litter, increased the frequency of litter resorption, produced a delay in bone formation and induced pathological changes of fetal organs and tissues. The congenital malformations were noted in fetuses after injection of higher doses of Ascaris homogenate (exencephaly, craniomeningocele and internal hydrocephalus). No malformations were noted in control groups and after injection of minimum dose of the homogenate. The symptoms that occurred after administration of the tegumental homogenate to pregnant mice included: decreased body weight gain (p<0.001) as compared to controls, vaginal hemorrhage, intrauterine resorption of litter and mortality. These signs suggest that the Ascaris homogenate causes maternal toxicity.

Abnormalities, Drug-Induced↗

PubMed1976

Elevated levels of IgE antibodies to ascaris and mite antigens in Papua New Guinea.

Levels of IgE as well as specific IgE antibodies to ascaris and mite have been studied in two groups in Papua New Guinea (PNG), patients with primary liver carcinoma (PLC) and normal blood donors, and in two groups in Japan, normal subjects and asthmatic patients. A radioallergosorbent test was used to measure IgE antibodies to ascaris and mite antigens. Much higher levels of IgE were found in the Papua New Guinean subjects than the normal Japanese subjects. Also levels of IgE antibodies to ascaris were much higher in Papua New Guineans than in the Japanese subjects. Though similar results were observed in IgE antibodies to mite, difference between normal Papua New Guineans and normal Japanese was small, whereas difference between the patients with PLC in PNG and the normal Japanese subjects was very large. Highest levels of IgE antibodies to mite were detected in Japanese with asthma. No correlations were observed among IgE levels, levels of IgE antibodies to ascaris and levels of IgE antibodies to mite. It is concluded that both ascaris and mite IgE antibodies contribute the very high levels of IgE seen in Papua New Guineans, but many other factors may be operative.

Antibodies↗

PubMed1989

[Inhalation of a precursor analogue of vasoactive intestinal polypeptide (Leu17 VIP-Gly-Lys) protects ascaris-induced bronchoconstriction in dog].

We studied in vivo the effects of pre-inhalations of vasoactive intestinal polypeptide (VIP) and a precursor analogue of VIP (Leu17 VIP-Gly-Lys: preVIP) in mongrel dogs bronchoconstricted by ascaris. An inhalation of preVIP solution (2 mg/5 ml saline) gave significant protection for 120 min against increases in respiratory resistance (Rrs) and decreases in dynamic compliance (Cdyn) induced by ascaris challenges. An inhalation of VIP solution (2 mg/ml saline) also gave significant protection for 120 min against increases in Rrs induced by ascaris challenges. Protective effect of the inhalation of preVIP against ascaris-induced bronchoconstriction was more potent than that of VIP. The inhalations of preVIP and VIP solution did not change systemic blood pressure or heart rate. These results indicate that inhalations of preVIP or VIP solution would attenuate ascaris-induced bronchoconstriction in dogs without affecting cardiovascular dynamics.

Administration, Inhalation↗

PubMed1989

Evaluation of a sanitation programme using eggs of Ascaris lumbricoides in household yard soils as indicators.

Soil samples were analysed for the presence of Ascaris lumbricoides eggs as indicators of environmental pollution in household yards in Maputo, Mozambique, with the objective of evaluating the impact of a programme for the promotion of improved latrine construction. The locations for soil sample collection were defined by a random grid on which household activities were mapped. In addition, parasitological examinations were carried out amongst household residents. No significant difference was found between the type of latrine in use and the presence of Ascaris eggs in the soil or human Ascaris infection. Households with at least one infected person appeared more likely to have Ascaris eggs in the yard. It was notable that egg counts around the latrines were only slightly greater than in other areas of the yard and less than those immediately in front of the dwelling. This is taken to indicate that faecal pollution of the household environment is due more to promiscuous defecation than to poor construction or maintenance of the latrines. The findings highlight the need to complement sanitation 'hardware' with the necessary health education 'software'. Ascaris eggs are useful indicators but robust standardized methods are needed for their extraction from household soils.

Adolescent↗

PubMed1983

Induction of IgE-mediated cutaneous, cellular, and airway reactivity in rhesus monkeys by Ascaris suum infection.

In order to maintain a colony of rhesus monkeys with IgE-mediated Ascaris asthma, we evaluated the response of four animals to infection with Ascaris suum ova. All four animals developed immediate-type cutaneous reactivity and airway responses. Serum IgE and IgG antibody responses against Ascaris antigen, as quantitated by the ELISA, were seen in all animals. Peripheral blood histamine release after stimulation with Ascaris antigen was positive in all animals. Airway reactivity to aerosol challenge with Ascaris antigen became positive in all animals and has remained positive for 6 months in three of four animals. Both standard and threshold dose airway types of responses were present. Except for transient eosinophilia, the animals remained in good health. The studies demonstrate that infection with A. suum results in rhesus monkeys with IgE-mediated immediate-type reactivity that simulates the naturally occurring model of asthma.

Animals↗

PubMed1983

Laboratory infection of primates with Ascaris suum to provide a model of allergic bronchoconstriction.

Wild-caught non-human primates are naturally sensitive to Ascaris antigen and provide a useful model for studying atopic asthma. The present study was carried out to determine the effect of experimentally infecting home-bred macaques with the nematode Ascaris suum and hence provide an alternative for the naturally occurring model. Following oral infection with the parasite the animals developed a blood eosinophilia and specific antibodies to purified Ascaris antigen. These antibodies appeared to be of the IgE class as they could be detected by a radiometric assay using a radiolabelled antibody to human IgE. However, on further investigation, using the passive cutaneous anaphylaxis test, two classes of antibody were found, a heat labile (56 degrees C) and a heat stable antibody. Lung lavage cells taken from monkeys infected with Ascaris suum were shown to include cells morphologically characteristic of mast cells and released histamine when challenged in vitro with Ascaris antigen. Hence this model of immediate hypersensitivity provides a simple alternative to the less accessible natural model.

Animals↗

PubMed1982

Enzyme polymorphism in Ascaris suum (Nematoda).

The potential of multilocus electrophoretic studies for providing insight into the population biology of parasitic organisms was studied using the swine parasite Ascaris suum suum. Thirty-eight loci encoding enzymatic or nonenzymatic proteins have been resolved in extracts of adult worms by starch-gel electrophoresis. A preliminary study of variation in Ascaris from eastern Iowa revealed an average heterozygosity of 6.6%. Allele frequencies at six polymorphic loci were similar in males and females and genotypic frequencies were in accord with those expected in a single, randomly mating population; however, the significant linkage disequilibrium between Pep-2 and Es-3 suggested that there may be some genetic substructuring within Ascaris from Iowa. Genetic comparisons of Ascaris from Iowa with Ascaris from New Jersey and Maryland indicated slight differences between eastern and midwestern populations, as well as between the east coast localities. Larger samples from more locations are needed before any statistical significance can be attached to these differences; however, qualitative comparisons suggest that the differentiation is a biological reality. Knowledge of the population biology of this and other parasites may contribute to planning effective control programs.

Animals↗