Blood feeding in juvenile Paragnathia formica (Isopoda: Gnathiidae): biochemical characterization of trypsin inhibitors, detection of anticoagulants, and molecular identification of fish hosts

Manship, B.M., Walker, A.J., Jones, L.A. and Davies, A.J. (2012) Blood feeding in juvenile Paragnathia formica (Isopoda: Gnathiidae): biochemical characterization of trypsin inhibitors, detection of anticoagulants, and molecular identification of fish hosts. Parasitology, 139(6), pp. 744-754. ISSN (print) 0031-1820

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Abstract

SUMMARYThe 3 post-marsupial juvenile stages of the gnathiid isopod, Paragnathia formica, are haematophagous ectoparasites of fishes that may, in heavy infestations, cause host mortality. Protein digestion in fed stage 3 juveniles is accomplished by cysteine proteinases, but what bioactive compounds attenuate host haemostatic, inflammatory and immunological responses during feeding is unknown. Trypsin inhibitory activity and anticoagulant activity were detected in crude extracts of unfed P. formica stage 1 juveniles; fractionation of stage 1 crude extracts by ion exchange chromatography resulted in 3 preparations each displaying these bioactivities. Further characterization revealed anti-thrombin activity in 2 of these preparations, whilst the third displayed the strongest anticoagulant activity that targeted a factor of the intrinsic coagulation pathway. Three trypsin inhibitors (18 kDa, 21 kDa, and 22 kDa) were also detected using reverse zymography. In parallel, homogenates of fed stage 2 and 3 juveniles were used to identify their fish hosts by amplifying the 16S mitochondrial rDNA and 18S genomic rDNA vertebrate gene regions. Blood from at least 4 fish families had been ingested by separate individuals during feeding. This study demonstrates that trypsin inhibitors and anticoagulants are present in P. formica juveniles which could suppress host haemostatic, inflammatory and immunological responses during feeding, and that juveniles are not host specific.

Item Type: Article
Uncontrolled Keywords: 'Paragnathia formica', fish ectoparasite, blood feeding, host-parasite interactions, serine protease inhibitor, anticoagulants, serine proteinase-inhibitors, 'Meinertia-oestroides risso', 'Boophilus-microplus', salivary-glands, lizard island, 'Lepeophtheirus-salmonis', protease inhibitor, thrombin inhibitor, 'Aedes-aegypti', gut contents
Research Area: Biological sciences
Faculty, School or Research Centre: Faculty of Science, Engineering and Computing > School of Life Sciences
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Depositing User: Automatic Import Agent
Date Deposited: 19 Apr 2012 11:01
Last Modified: 26 Apr 2013 14:52
URI: http://eprints.kingston.ac.uk/id/eprint/22224

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