Effect of anthelmintics on phosphatases in Ascaridia galli.

In vitro addition of the drugs tetramisole (TMS) and levamisole (LMS) caused an inhibition of the specific activities of acid phosphatase and Mg(++)-dependent adenosine triphosphatase. The inhibition was non-competitive in nature. No significant inhibition was caused by TMS in the activity of glucose-6-phosphatase, but LMS inhibited the enzyme in a non-competitive manner. The activity of alkaline phosphatase was, however, increased in the presence of both TMS and LMS.     

Study of the acetylcholinesterase activity of Ascaridia galli: kinetic properties and the effect of anthelmintics.

Acetylcholinesterase (EC 3.1.1.7) activity was demonstrated in whole worm homogenates of adult Ascaridia galli with acetylthiocholine as substrate. The pH optimum was not measurable because of an autohydrolysis of the substrate. The Michaelis constant (Km) was 4 mM with saturation by excess substrate. Optimum enzyme activity was noted at a protein concentration of 200 mg/ml assay medium and at a temperature of 37 degrees C. Arrhenius plot of temperature dependence of the enzyme activity showed an energy of activation (delta Ea) of 28.962 K joule/mole above, and 25.448 K joule/mole below, the transition temperature (37 degrees C). Complete inhibition by eserine (physostigmine), a specific and classical acetylcholinesterase inhibitor, established the identity of the enzyme. A marginally higher enzyme activity was observed in females than in males as well as in homogenates from worms of mixed sexes. The enzyme was markedly activated by divalent metal cations such as Fe2+, Mg2+, Cd2+, Cu2+, Zn2+ and Ca2+, while Co2+ and Mn2+ inhibited the activity. Piperazine adipate at a concentration of 10(-3) M caused 45.5% and albendazole, a benzimidazole anthelmintic, 37.5% inhibition in the enzyme activity, while levamisole and mebendazole proved to be practically ineffective, causing an inhibition of 12 and 9%, respectively.     

Lipid metabolism and low molecular weight solute uptake in Ascaridia galli

Adult Ascaridia galli, an intestinal nematode parasite of fowl, reveals a large variety of complex lipids such as phospholipids containing choline, ethanolamine, inositol, serine and glycerol. Lysophospholipid species, vinyl ether phospholipid (plasmalogen), neutral acylglycerols, cholesterol and non-esterified fatty acids are also present. Sugar-containing lipids, such as cerebrosides, sulphatides and gangliosides are abundantly present. Female parasites contain more lipids, particularly acylglycerols and phospholipids. Acylglycerols, phosphatidyl choline, phosphatidyl ethanolamine and glycolipids incorporate a large amount of radiolabelled precursor substrate in A. galli. The presence of important enzymes of lipid biosynthesis like glucose-6-phosphate dehydrogenase, malate dehydrogenase and hydroxymethyl glutaryl-CoA reductase as well as an enzyme of lipid ester hydrolysis, triacylglycerol lipase is detected in the parasite. These enzymes show subcellular distribution patterns and Michaelis-Menten kinetic characteristics comparable with that from rat liver homogenate. Studies on the uptake of labelled precursor molecules for lipid biosynthesis, glucose, acetate and palmitate show that the parasites can take up the isotopes readily in a time-dependent manner, showing substrate saturation kinetics, dependence upon Na ions, and can be inhibited by the presence of the bile salts sodium cholate and sodium deoxycholate. The substrate affinity constant (Kt) and maximum apparent velocity of glucose uptake in A. galli were found to be 9.09 mM and 26.67 mM per 100 mg tissue dry weight per min at 37 degrees C.     

The effect of levamisole and albendazole on some enzymes of Ascaridia galli and Heterakis gallinae

Ascaridia galli and Heterakis gallinae obtained from the common fowl Gallus gallus were exposed to 10(-2)-10(-5)M levamisole and albendazole; both compounds caused death of the parasites in vitro. The effect of the drugs was investigated on homogenates of the treated worms. Albendazole, at 10(-2)M, inhibited oxaloacetate reduction by 67 and 53% and malate oxidation by 21 and 17% in A. galli and H. gallinae, respectively, whereas 10(-4)M levamisole completely inhibited malate dehydrogenase activity in both directions in the two parasites. Lactate dehydrogenase was not affected significantly by either anthelmintic. Aldolase activity was diminished by 57 and 32% in A. galli and H. gallinae, respectively, with 10(-4)M levamisole. Levamisole at 10(-4)M also inhibited the activity of acid and alkaline phosphomonoesterase and cholinesterase. Albendazole had no significant effect on these enzymes in either parasite. Malate dehydrogenase and cholinesterase activity of the host tissue (intestine and caecum) was also reduced significantly with 10(-2) and 10(-3)M levamisole. These studies indicated a multiple mode of action of levamisole and albendazole.     

In vitro hatching of the infective eggs of Ascaridia galli in tissue extracts

Extracts of proventriculus (PE) and small intestine (IE) of fowl were used, for the first time, as media for the in vitro hatching of infective eggs of Ascaridia galli. Hatching was successful in a mixture of equal parts of PE and IE (MIP) under normal air and under different concentrations of CO2, but not under 100% CO2. A very highly significant retardation (P less than 0.001) in the rate of hatching appeared as the concentration of CO2 was increased, indicating that high levels of CO2 inhibit the process of hatching. 100% of the eggs hatched in PE in 40.5 min whereas they did not hatch at all in IE, suggesting that IE alone has no influence on egg hatching. The shortest time taken for 100% of the eggs to hatch in this study suggests that the present method of hatching is faster than all previous methods used by different workers.     

The effect of Plasmodium gallinaceum on a challenge infection with Ascaridia galli in chickens

The effect of a primary infection with the haemoparasite Plasmodium gallinaceum on the establishment of a challenge infection with the nematode Ascaridia galli in chickens was studied. Four groups were infected as follows. Group 1: inoculated intravenously with 10(6) P. gallinaceum-infected erythrocytes on day 0; group 2: orally infected with 500 embryonated A. galli eggs on day 10; group 3: infected with P. gallinaceum on day 0 and A. galli on day 10; and group 3: non-infected control birds. The results of this investigation demonstrates that a primary infection with P. gallinaceum in chickens alters the course of a subsequent infection with A. galli. Thus, an antagonistic effect was seen in which the malaria infection caused a significant reduction on the establishment of the nematode in concurrently infected animals.     

Effect of parbendazole and piperazine adipate on the activity of some enzymes of Ascaridia galli and Heterakis gallinae

Adult Ascaridia galli and Heterakis gallinae obtained from the fowl (Gallus gallus) were treated in vitro with 10(-2) to 10(-5) M parbendazole and piperazine adipate for 10-60 min at 38 degrees C. Both the compounds at 10(-2) M caused mortality of A. galli and H. gallinae after a maximum of 30 min exposure. The effect of the drugs on the homogenates of the treated worm was investigated. Parbendazole (10(-2) M) inhibited malate oxidation by 68% in A. galli and 62% in H. gallinae. Piperazine adipate (10(-2) M) inhibited malate oxidation by 78% in both parasites. In A. galli oxaloacetate reduction was inhibited by 41 and 26% by 10(-2) M parbendazole and piperazine adipate, respectively; with H. gallinae this inhibition was found to be 39 and 55%, respectively. Aldolase activity in both the parasites was also inhibited by 10(-2) M parbendazole and piperazine adipate. Both compounds caused an inhibition of acid phosphomonoesterase activity, but the activities of lactate dehydrogenase and alkaline phosphomonoesterase were not affected significantly. Parbendazole (10(-2) M) had no significant effect on the cholinesterase activity of these parasites, but piperazine adipate (10(-2) M) caused an inhibition of 96% in A. galli and 93% in H. gallinae. The possible mode of action of the drugs is discussed.     

Anthelmintic activity of pyrantel tartrate against Ascaridia galli in fowls.

At a dose of 15 mg/kg body weight, pyrantel tartrate was 18-51, 99-63, 100 and 100 per cent effective in chickens treated at 10, 20, 30 and 40 days respectively after infection with Ascaridia galli. Similarly, 25 mg/kg was 14-44, 100, 100 and 99-63 per cent effective.     

The effect of concurrent infections with Pasteurella multocida and Ascaridia galli on free range chickens

Pasteurella multocida and Ascaridia galli are observed with high prevalences in free range chickens in Denmark, but the impact is unknown. A study was carried out to examine the interaction between A. galli and P. multocida in chickens and the impact on production.Five groups, each with 20 18-week-old Lohmann Brown chickens were infected. Group 1 was orally infected with 1000+/-50 embryonated A. galli eggs. Group 2 received 10(4) cfu P. multocida intratracheally. Group 3 was infected with A. galli and subsequently with P. multocida. Group 4 was infected with P. multocida followed by A. galli. Group 5 was the control. The study ran for 11 weeks where clinical manifestations, weight gain and egg production were recorded. Excretion of P. multocida was determined on individual basis and blood smears were made for differential counts. At the end of the study pathological lesions and the number of adult worms, larvae and eggs in the faeces were recorded.The birds were more severely affected when infected with both pathogens compared to single infections with A. galli or P. multocida, respectively. A lower weight gain and egg production was observed with dual infections. A. galli infection followed by a secondary P. multocida infection resulted in more birds with pathological lesions and continued P. multocida excretion.In conclusion a negative interaction between A. galli and P. multocida was observed and it is postulated that free range chickens are at higher risk of being subjected to outbreaks of fowl cholera when they are infected with A. galli.     

In vitro effect of some anthelmintics on lactate dehydrogenase activity of Cotylophoron cotylophorum (Digenea: paramphistomidae)

Effects of praziquantel (PZQ), levamisole (LEV), mebendazole (MBZ), fenbendazole (FBZ) and albendazole (ABZ) on the lactate dehydrogenase (LDH) activity of Cotylophoron cotylophorum were studied in vitro. Maximum levels of inhibition of LDH catalysing both oxidation and reduction reactions were observed in PZQ- and LEV-treated worms. Similarly, benzimidazoles - MBZ, FBZ and ABZ - have also significantly inhibited the activity of LDH catalysing the oxidation of lactate; whereas the activity of LDH catalysing the reduction of pyruvate was accelerated. This affects the mitochondrial energy generating process which ultimately proves fatal to the parasite. Therefore, the mode of action of benzimidazoles is primarily on the activation of LDH catalysing the conversion of pyruvate to lactate.     

Effect of irradiated Ascaridia galli eggs on growth and cell-mediated immune responses in chickens

Growth and cell-mediated immune (CMI) responses were studied in 7-day-old chicks given orally 1000 irradiated (12.5 kR) or normal infective eggs of Ascaridia galli. Chicks immunised with irradiated eggs showed normal weight gains. CMI responses, as assessed by dinitrofluorobenzene (DNFB)-induced contact and delayed hypersensitivity reactions, were enhanced in the immunised group as compared with healthy controls, suggesting stimulation of CMI responses due to irradiation of A. galli eggs. CMI as well as growth responses were, however, found to be depressed in the birds administered normal infective eggs of A. galli. The present study highlights the role of the CMI response in protection against A. galli infection.     

Energy and nitrogen metabolism of diseased chickens: interaction of Ascaridia galli infestation and vitamin A status.

1. Effects of Ascaridia galli infection on the energy and nitrogen (N) metabolism were studied on groups of 5 cross-bred cockerels aged about 5 weeks and given a diet deficient or adequate in vitamin A at two levels of feeding in respiration chambers. 2. Metabolisability of dietary energy was 67% and N retention 33% in infected chickens compared with 71 and 41% respectively, in uninfected chickens. 3. Maintenance energy requirement of vitamin A-deficient birds was 882 kJ/kgW d compared with 998 kJ/kgW d for normal birds. N balance of the deficient chickens was also less when compared at the same energy balance. Infection did not affect maintenance energy requirement nor N balance. 4. Starvation heat production of infected chickens (619 kJ/kgW d) was higher than that of uninfected controls (586 kJ/kgW d). When infection treatments were combined, vitamin A-adequate chickens had a higher heat production (615 kJ/kg d) than the vitamin A-deficient (580 kJ/kgW d). Endogenous N excretion (mg/gW) was less in vitamin A-deficient than in adequate, starved birds. 5. Deficient chickens had undetectable liver reserves of vitamin A and only very low plasma concentrations. There was a difference in the length of larvae (17 d after infection) associated with vitamin A status, and with level of feeding.