Article

Identification of secreted cysteine proteases from the parasitic nematode Haemonchus contortus detected by biotinylated inhibitors.

Division of Infection Biology, Department of Infectious Diseases and Immunology, Utrecht University, Yalelaan, 1, 3584CL, Utrecht, The Netherlands.
Infection and Immunity (Impact Factor: 4.16). 04/2006; 74(3):1989-93. DOI: 10.1128/IAI.74.3.1989-1993.2006
Source: PubMed

ABSTRACT Seven cathepsin B-like cysteine proteases (CBLs) were identified from the immunoprotective excretory-secretory products of Haemonchus contortus. Two-dimensional (2-D) zymography and biotinylated inhibitors were employed to localize active CBLs in 2-D protein gels. Mass spectrometry provided the identification of AC-4, HMCP1, HMCP2, and GCP7 as well as three novel CBLs encoded by clustered expressed sequence tags.

Download full-text

Full-text

Available from: Albert J R Heck, Feb 01, 2014
0 Followers
 · 
93 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 10 GHz AlGaN/GaN HEMT-based dielectric resonator oscillator (DRO) is presented. This device exhibits -118dBc/Hz phase noise at 100KHz offset frequency range and is the lowest yet reported. This phase noise and power capabilities of GaN HEMT oscillators are compared to those of two mature technologies, an Infineon SiGe HBT (BFP620) and Transcom GaAs pHEMT (TC1401). The oscillator output power density using a GaN HEMT was found to be 14 times greater than using an equivalent GaAs pHEMT. Phase noise improvements between two different GaN devices, resulting from developments in GaN technology, are also presented.
    Microwave Symposium Digest, 2004 IEEE MTT-S International; 07/2004
  • [Show abstract] [Hide abstract]
    ABSTRACT: Proteases frequently function not only as individual enzymes but also in cascades or networks. A notable evolutionary switch occurred in one such protease network that is involved in protein digestion in the intestine. In vertebrates, this is largely the work of trypsin family serine proteases, whereas in invertebrates, cysteine proteases of the papain family and aspartic proteases assume the role. Utilizing a combination of protease class-specific inhibitors and RNA interference, we deconvoluted such a network of major endopeptidases functioning in invertebrate intestinal protein digestion, using the parasitic helminth, Schistosoma mansoni as an experimental model. We show that initial degradation of host blood proteins is ordered, occasionally redundant, and substrate-specific. Although inhibition of parasite cathepsin D had a greater effect on primary cleavage of hemoglobin, inhibition of cathepsin B predominated in albumin degradation. Nevertheless, in both cases, inhibitor combinations were synergistic. An asparaginyl endopeptidase (legumain) also synergized with cathepsin B and L in protein digestion, either by zymogen activation or facilitating substrate cleavage. This protease network operates optimally in acidic pH compartments either in the gut lumen or in vacuoles of the intestinal lining cells. Defining the role of each of these major enzymes now provides a clearer understanding of the function of a complex protease network that is conserved throughout invertebrate evolution. It also provides insights into which of these proteases are logical targets for development of chemotherapy for schistosomiasis, a major global health problem.
    Journal of Biological Chemistry 01/2007; 281(51):39316-29. DOI:10.1074/jbc.M607128200 · 4.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the present study, a bioinformatic-microarray approach was employed for the analysis of selected expressed sequence tags (ESTs) from Haemonchus contortus, a key parasitic nematode of small ruminants. Following a bioinformatic analysis of EST data using a semiautomated pipeline, 1885 representative ESTs (rESTs) were selected, to which oligonucleotides (three per EST) were designed and spotted on to a microarray. This microarray was hybridized with cyanine-dye labelled cRNA probes synthesized from RNA from female or male adults of H. contortus. Differential hybridisation was displayed for 301 of the 1885 rESTs ( approximately 16%). Of these, 165 (55%) had significantly greater signal intensities for female cRNA and 136 (45%) for male cRNA. Of these, 113 with increased signals in female or male H. contortus had homologues in Caenorhabditis elegans, predicted to function in metabolism, information storage and processing, cellular processes and signalling, and embryonic and/or larval development. Of the rESTs with no known homologues in C. elegans, 24 ( approximately 40%) had homologues in other nematodes, four had homologues in various other organisms and 30 (52%) had no homology to any sequence in current gene databases. A genetic interaction network was predicted for the C. elegans orthologues of the gender-enriched H. contortus genes, and a focused analysis of a subset revealed a tight network of molecules involved in amino acid, carbohydrate or lipid transport and metabolism, energy production and conversion, translation, ribosomal structure and biogenesis and, importantly, those associated with meiosis and/or mitosis in the germline during oogenesis or spermatogenesis. This study provides a foundation for the molecular, biochemical and functional exploration of selected molecules with differential transcription profiles in H. contortus, for further microarray analyses of transcription in different developmental stages of H. contortus, and for an extended functional analysis once the full genome sequence of this nematode is known.
    International Journal for Parasitology 02/2008; 38(1):65-83. DOI:10.1016/j.ijpara.2007.07.001 · 3.40 Impact Factor