Hatching mechanisms of nematodes

Perry, R. N.; Clarke, A. J.

doi:10.1017/s0031182000085413

Cited by 45 publications

(21 citation statements)

References 49 publications

(50 reference statements)

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“…The natural hatching of eggs in several nematode species is a dynamic process characterized by the termination of the dormant stage and the initiation of active biochemical processes, particularly changes in the permeability of the eggshell (Perry and Clarke 1981). As T. suis resides in the cecum and the upper part of the colon, we suspect that various gastrointestinal enzymes, pH along the digestion system, resident gut microbiota, and bacterial fermentation products in the large intestine trigger the hatching process of TSO.…”

Section: Introductionmentioning

confidence: 99%

In vitro hatching of Trichuris suis eggs

Vejzagić

Thamsborg

Kringel³

et al. 2015

Parasitol Res

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Eggs of the pig whipworm, Trichuris suis ova (TSO), are currently tested in human clinical trials for their potential immunomodulatory capacity. The biological potency of TSO (egg viability and infectivity) is traditionally assessed in Göttingen minipigs as the establishment of intestinal larvae after inoculation with a known number of eggs. To minimize testing in animal models, development of an in vitro egg hatching assay is proposed as a reliable, cost-effective, and a faster alternative to test the egg viability. The present study aimed to investigate the influence of different chemical, physical, and biological factors on egg hatching. Thus, in a series of experiments and in different combinations, the eggs were stimulated with glass beads, artificial gastric juice, bile salt and trypsin solution, fermentation gut medium, or stimulated with mucosal scrapings from the ileum and the large intestine of the infected and uninfected Göttingen minipig. Mechanical stimulation with glass beads presented a simple and reproducible method for egg hatching. However, incubation of eggs with mucosal scrapings from the ileum, caecum, and colon for 24 h at 38 °C significantly increased hatching.

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Section: Introductionmentioning

confidence: 99%

In vitro hatching of Trichuris suis eggs

Vejzagić

Thamsborg

Kringel³

et al. 2015

Parasitol Res

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“…Perry and Clarke [1] suggested that concentrations of trehalose in the egg fluid may suppress enzymatic activity so that the release of the sugar by alterations in eggshell permeability leads to activation of the hatching enzymes. The inhibition of enzymatic activity in egg supernatant from T. colubriformis by 0.063 M trehalose in this study may support their contention.…”

Section: Resultsmentioning

confidence: 99%

“…Hatching mechanism of nematode eggs may require various processes such as permeability changes in the eggshell, enzymatic activity and mechanical penetration by the enclosed larva [1]. Few studies have investigated the enzymatic activity in eggs of zooparasitic nematodes.…”

Section: Introductionmentioning

confidence: 99%

Exopeptidase activity in eggs ofTrichostrongylus colubriformis(Nematoda)

Woods

Lathem

Parish

et al. 1986

International Journal of Invertebrate Reproduction and Developm

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279A supernatant from eggs of the ruminant nematode Trichostrongylus colubriformis contained an enzyme that was similar to leucine aminopeptidase (LAP), based on hydrolysis of the substrate L-leucine ,8-naphthylamide to ,8-naphthylamine. A Michaelis-Menten constant (Km) of 0.155 mM was obtained. Rate of hydrolysis of 16 substrates revealed that L-phenylalanine and L-tyrosine ,8-naphthylamides were hydrolyzed most readily while seven additional substrates were hydrolyzed at lesser rates. The optimum pH for enzymatic activity was 6.75-7.5. Enzymatic activity was lost by heating the egg supernatant to 60°C for 5 min or freezing at 0°C for 28 days. Addition of millimolar concentrations of the chlorides of zinc, manganese and magnesium to the egg supernatant had no stimulatory effect on enzyme activity while 10 and 100 mM concentrations significantly reduced activity. Ethylenediamine tetraacetic acid at 10-4 M had no effect on enzymatic activity. Activity was inhibited by 10-4 M 1,10-phenanthroline, but the inhibition was reversed by zinc chloride at 10-3 M. Di-isopropylphosphofluoridate at 10-3 M reduced enzymatic activity moderately. Enzyme activity in egg supernatant increased 2.2-fold from 21 days to 60-90 days of a primary infection in the host while a 3.3-fold increase was found in primary versus secondary infections.

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“…It has been amply demonstrated that plant parasitic nematode egg hatching is stimulated by root exudates (e.g., Perry and Clarke, 1981;Perry and Gaur, 1996;Dennijs and Lock, 1992;Gaur et al, 2000;Devine and Jones, 2001;Wesemael et al, 2006;Pudasaini et al, 2008;Khokon et al, 2009;Oka and Mizukubo, 2009). For instance, a key hatch-stimulating substance for soybean cyst nematode was successfully isolated from soybean roots (Masamune et al, 1982).…”

Section: Management Of Plant Parasitic Nematodes Using Root-produced mentioning

confidence: 99%

Manipulation of Chemically Mediated Interactions in Agricultural Soils to Enhance the Control of Crop Pests and to Improve Crop Yield

Hiltpold

Turlings

2012

J Chem Ecol

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In most agro-ecosystems the organisms that feed on plant roots have an important impact on crop yield and can impose tremendous costs to farmers. Similar to aboveground pests, they rely on a broad range of chemical cues to locate their host plant. In their turn, plants have co-evolved a large arsenal of direct and indirect defense to face these attacks. For instance, insect herbivory induces the synthesis and release of specific volatile compounds in plants. These volatiles have been shown to be highly attractive to natural enemies of the herbivores, such as parasitoids, predators, or entomopathogenic nematodes. So far few of the key compounds mediating these so-called tritrophic interactions have been identified and only few genes and biochemical pathways responsible for the production of the emitted volatiles have been elucidated and described. Roots also exude chemicals that directly impact belowground herbivores by altering their behavior or development. Many of these compounds remain unknown, but the identification of, for instance, a key compound that triggers nematode egg hatching to some plant parasitic nematodes has great potential for application in crop protection. These advances in understanding the chemical emissions and their role in ecological signaling open novel ways to manipulate plant exudates in order to enhance their natural defense properties. The potential of this approach is discussed, and we identify several gaps in our knowledge and steps that need to be taken to arrive at ecologically sound strategies for belowground pest management.

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Hatching mechanisms of nematodes

Cited by 45 publications

References 49 publications

In vitro hatching of Trichuris suis eggs

In vitro hatching of Trichuris suis eggs

Exopeptidase activity in eggs ofTrichostrongylus colubriformis(Nematoda)

Manipulation of Chemically Mediated Interactions in Agricultural Soils to Enhance the Control of Crop Pests and to Improve Crop Yield

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