Nitrogen excretion by the sheep abomasal parasite Teladorsagia circumcincta

Simpson, H.V.; Muhamad, Noorzaid; Walker, L S; Simcock, David C.; Brown, SC; Pedley, Kevin C.

doi:10.1016/j.exppara.2009.05.003

Cited by 7 publications

(1 citation statement)

References 49 publications

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“…stimulation of cell proliferation (Huby et al 1995;. The molecules responsible have generally not been identified, although ES products are known to contain many proteins (Yatsuda et al 2003), proteases and other enzymes (Lee and Hodsden 1963;Knox and Jones 1990;Gamble and Mansfield 1996;Kiel et al 2007), metabolic end products (Ward 1974;Kapur and Sood 1991;Bryant 1993;Simpson et al 2009) and prostaglandins (Belley and Chadee 1995;Brattig et al 2006).…”

Section: Introductionmentioning

confidence: 97%

Neutrophil and eosinophil chemotactic factors in the excretory/secretory products of sheep abomasal nematode parasites

2011

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Both eosinophil chemotactic factor (ECF) and neutrophil chemotactic factor (NCF) activities were demonstrated in excretory/secretory (ES) products and homogenates of Haemonchus contortus and Teladorsagia circumcincta larvae and adult worms in a modified checkerboard assay using a micro-chemotaxis chamber. Neutrophil chemotaxis was seen in 28 of 35 experiments and eosinophil chemotaxis in 20 of 38 experiments. Chemokinetic activity for neutrophils and eosinophils (accounting for 40-50% of total cell migration) was also apparent in only three parasite products for each cell type. Significant NCF activity was present in six of seven adult worm ES products (three of four from T. circumcincta and in all three from H. contortus) and ECF activity in four of five adult ES products, whereas fewer L3 incubates, particularly of T. circumcincta, contained chemotactic activity. All parasite homogenates, with one exception for ECF, were chemotactic for both neutrophils and eosinophils. The sequential use of cellulose ultrafiltration membranes of decreasing pore size did not identify precisely the molecular weight of the NCF and ECF but indicated that the active chemicals were greater than 10 kDa and probably greater than 30 kDa.

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Section: Introductionmentioning

confidence: 97%

Neutrophil and eosinophil chemotactic factors in the excretory/secretory products of sheep abomasal nematode parasites

2011

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The kinetic properties of the glutamate dehydrogenase of Teladorsagia circumcincta and their significance for the lifestyle of the parasite

Muhamad

Simcock

Pedley

et al. 2011

Comparative Biochemistry and Physiology Part B: Biochemistry an

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Like other nematodes, both L 3 and adult Teladosagia circumcincta secrete or excrete NH 3 /NH 4 + , but the reactions involved in the production are unclear. Glutamate dehydrogenase is a significant source NH 3 /NH 4 + in some species, but previous reports indicate that the enzyme is absent from L 3 Haemonchus contortus. We show that glutamate dehydrogenase was active in both L 3 and adult T. circumcincta. The apparent K m s of the L 3 enzyme differed from those of the adult enzyme, the most significant of these being the increase in the K m for NH 4 + from 18 mM in L 3 to 49 mM in adults. The apparent V max of the oxidative deamination reaction was greater than that of the reductive reaction in L 3 , but this was reversed in adults. The activity of the oxidative reaction of the L 3 enzyme was not affected by adenine nucleotides, but that of the reductive reaction was stimulated significantly by either ADP or ATP. The L 3 enzyme was more active with NAD + than it was with NADP + , although the activities supported by NADH and NADPH were similar at saturating concentrations.While the activity of the oxidative reaction was sufficient to account for the NH 3 /NH 4 + efflux we have previously reported, the reductive amination reaction was likely to be more active.

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Glutamate synthase, but not GABA shunt enzymes, contributes to nitrogen metabolism of the sheep abomasal nematode parasites Haemonchus contortus and Teladorsagia circumcincta

Umair

Bland

Simpson

2011

Experimental Parasitology

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Nitrogen excretion by the sheep abomasal parasite Teladorsagia circumcincta

Cited by 7 publications

References 49 publications

Neutrophil and eosinophil chemotactic factors in the excretory/secretory products of sheep abomasal nematode parasites

Neutrophil and eosinophil chemotactic factors in the excretory/secretory products of sheep abomasal nematode parasites

The kinetic properties of the glutamate dehydrogenase of Teladorsagia circumcincta and their significance for the lifestyle of the parasite

Glutamate synthase, but not GABA shunt enzymes, contributes to nitrogen metabolism of the sheep abomasal nematode parasites Haemonchus contortus and Teladorsagia circumcincta

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