The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Peter J. Hotez - One of the best experts on this subject based on the ideXlab platform.

  • ac ap 12 a novel factor xa anticoagulant peptide from the esophageal glands of adult Ancylostoma Caninum
    Molecular and Biochemical Parasitology, 2011
    Co-Authors: Desheng Jiang, Bin Zhan, Brian Keegan, Maria Elena Bottazzi, Reina S Mayor, Portia Gillespie, Peter J. Hotez
    Abstract:

    Abstract Immunoscreening an Ancylostoma Caninum cDNA library with canine hookworm-infected dog serum resulted in the isolation of a 461 bp cDNA encoding Ac -AP-12, a new 9.1 kDa anticoagulant peptide (100 amino acids) with 43–69% amino acid homology to other nematode anticoagulant peptides (NAPs) from Ancylostoma hookworms. Messenger RNA transcription and expression of Ac -AP-12 was unique to the adult stage of A. Caninum . The yeast expressed recombinant Ac -AP-12 demonstrated potent anticoagulant activity on human blood plasma in a concentration dependent manner, and was shown to specifically inhibit human factor Xa activity. Immunolocalization with specific rabbit antiserum showed that Ac -AP-12 was exclusively located in the esophageal glands of adult hookworm. Ac -AP-12 is hypothesized to facilitate both parasite blood feeding and digestion.

  • molecular cloning and characterization of ac tmp 2 a tissue inhibitor of metalloproteinase secreted by adult Ancylostoma Caninum
    Molecular and Biochemical Parasitology, 2008
    Co-Authors: Bin Zhan, Desheng Jiang, Richi Gupta, Susan P Y Wong, Stacia Bier, Gaddam Goud, Peter J. Hotez
    Abstract:

    Abstract Ac -TMP-2, an immunodominant hookworm antigen encoding a tissue inhibitor of metalloproteinase (TIMP) was cloned by immunoscreening an Ancylostoma Caninum larval cDNA library with sera pooled from dogs immunized with irradiated A. Caninum third stage larvae (ir-L3). The open reading frame of Ac-tmp-2 cDNA encoded a 244 amino acids (predicted molecular weight of 27.7 kDa), which shared a common N-terminus with other vertebrate and invertebrate TIMPs, including Ac -TMP-1, the most abundant adult hookworm secreted protein. However Ac -TMP-2 also contains an unusual multicopy (ten) repeat of the amino acid sequence, KTVEENDE. By immunoblotting, Ac -TMP-2 was detected only in adult hookworms and their excretory secretory products although the corresponding mRNA was also detected in L3. Immunolocalization with specific antiserum showed that native Ac -TMP-2 was located in adult worm’s esophagus and cephalic glands. Recombinant Ac -TMP-2 expressed in bacteria was highly immunogenic and recognized by ir-L3 immunized dog immune sera. The recombinant Ac -TMP-2 protein inhibited the human matrix metalloproteinases, MMP-2, MMP-7 and MMP-13. As an immunodominant protein having a possible role in the parasite–host relationship of canine hookworm infection, recombinant Ac -TMP-2 represents a plausible target for vaccine development.

  • molecular cloning and characterization of ac mtp 2 an astacin like metalloprotease released by adult Ancylostoma Caninum
    Molecular and Biochemical Parasitology, 2007
    Co-Authors: Jianjun Feng, Bin Zhan, Alex Loukas, Yueyuan Liu, Angela L. Williamson, Gaddam Goud, Sen Liu, Peter J. Hotez
    Abstract:

    Ac-MTP-2 is an astacin-like metalloprotease secreted by adult Ancylostoma Caninum hookworms. Ac-mtp-2 cDNA was cloned by immunoscreening a cDNA library with antisera prepared against adult A. Caninum excretory/secretory (ES) products. The full-length Ac-mtp-2 contains 850 bp cDNA encoding a 233 amino acid open reading frame (ORF) with 32% amino acid identity to Ce-NSP-4, a pharyngeal cell-derived secreted metalloprotease of the nematode Caenorhabditis elegans. The predicted ORF contained a conserved Met-turn sequence (SXMHY), but only a partial zinc-binding signature sequence (GXXXEHXRXER instead of HEXXHXXGXXHEXXRXDR) found in other astacins. However, by both gelatin gel electrophoresis and azocasein digestion, the recombinant Ac-MTP-2 exhibited proteolytic activity that was inhibited by the zinc chelator 1,10-phenanthroline and Ac-TMP, a putative tissue inhibitor of metalloprotease that was previously shown to be a highly abundant component of adult A. Caninum ES products. By RT-PCR, Western blot Ac-MTP-2 was found only expressed in adult hookworms and secreted in the adult ES products. Immunolocalization with antisera shows that Ac-MTP-2 is located to the esophageal glands (confirming its role as a secretory protein), as well as to the parasite uterus. It is hypothesized that Ac-MTP-2 functions in the extracorporeal digestion of the intestinal mucosal plug lodged in the buccal capsule of the adult parasite.

  • a pore forming haemolysin from the hookworm Ancylostoma Caninum
    International Journal for Parasitology, 2004
    Co-Authors: Tegan A Don, Peter J. Hotez, Alex Loukas, Malcolm K. Jones, Danielle J Smyth, P J Odonoghue
    Abstract:

    Hookworms feed on blood, but the mechanism by which they lyse ingested erythrocytes is unknown. Here we show that Ancylostoma Caninum, the common dog hookworm, expresses a detergent soluble, haemolytic factor. Activity was identified in both adult and larval stages, was heat-stable and unaffected by the addition of protease inhibitors, metal ions, chelators and reducing agents. Trypsin ablated lysis indicating that the haemolysin is a protein. A closely migrating doublet of hookworm proteins with apparent molecular weights of 60-65 kDa bound to the erythrocyte membrane after lysis of cells using both unlabeled and biotinylated detergent-solubilised hookworm extracts. In addition, separation of detergent-soluble parasite extracts using strong cation-exchange chromatography, resulted in purification of 60-65 kDa proteins with trypsin-sensitive haemolytic activity. Erythrocytes lysed with particulate, buffer-insoluble worm extracts were observed using scanning electron microscopy and appeared as red cell ghosts with approximately 100 nm diameter pores formed in the cell membranes. Red blood cell ghosts remained visible indicating that lysis was likely caused by pore formation and followed by osmotic disruption of the cell.

  • Ac-SAA-1, an immunodominant 16 kDa surface-associated antigen of infective larvae and adults of Ancylostoma Caninum.
    International journal for parasitology, 2004
    Co-Authors: Bin Zhan, Shu-hua Xiao, John M. Hawdon, Alex Loukas, Yueyuan Liu, Angela L. Williamson, Yan Wang, Hae-chou Xue, Peter J. Hotez
    Abstract:

    Abstract A cDNA encoding a surface-associated antigen was cloned from an Ancylostoma Caninum infective larvae (L 3 ) cDNA library by immunoscreening with pooled human immune sera. The sera were obtained from individuals living in an Ancylostoma duodenale hookworm-endemic region of China, who had light intensity infections and high antibody titers against A. Caninum L 3 . Ancylostoma Caninum surface-associated antigen-1 is encoded by an 843 bp mRNA with a predicted open reading frame of 162 amino acids. Recombinant Ancylostoma Caninum surface-associated antigen-1 was expressed in Escherichia coli and used to prepare a specific antiserum. A Western blot with anti- Ancylostoma Caninum surface-associated antigen-1 specific antiserum showed that native Ancylostoma Caninum surface-associated antigen-1 protein is expressed by both L 3 and adult hookworms; RT-PCR confirmed that the mRNA is transcribed in both stages. In adult hookworms, the protein localised to the basal layer of the cuticle and hypodermis of adult worms. Serological analysis determined that recombinant Ancylostoma Caninum surface-associated antigen-1 protein is recognised by 61% of human sera from a Necator americanus hookworm endemic area in China, indicating the antigen is immunodominant. Anti- Ancylostoma Caninum surface-associated antigen-1 antiserum partially inhibited (46.7%) invasion of hookworm L 3 into dog skin in vitro. Together these results suggest that Ancylostoma Caninum surface-associated antigen-1 offers promise as a protective vaccine antigen.

John M. Hawdon - One of the best experts on this subject based on the ideXlab platform.

  • Ancylostoma Caninum and other canine hookworms
    2021
    Co-Authors: John M. Hawdon, Kira A Wise
    Abstract:

    The hookworm Ancylostoma Caninum is the most common nematode parasite of dogs. Cosmopolitan in distribution, A. Caninum is a serious canine pathogen, causing blood loss, anemia, and sometimes death, especially in puppies. In addition, A. Caninum and related hookworms are zoonoses, and are capable of causing disease in humans. This chapter will first review the life cycle of A. Caninum, its pathology and treatment in dogs. Next, the diseases caused by A. Caninum and closely related canine hookworms in humans will be discussed, including cutaneous larva migrans, eosinophilic enteritis, and diffuse unilateral subacute neuroretinitis. Finally, evidence of the emergence of multidrug-resistant A. Caninum and its possible impact on diseases in both dogs and humans will be explored.

  • rna and protein synthesis is required for Ancylostoma Caninum larval activation
    Veterinary Parasitology, 2011
    Co-Authors: Dilyan I Dryanovski, Camille Dowling, Verena Gelmedin, John M. Hawdon
    Abstract:

    Abstract The developmentally arrested infective larva of hookworms encounters a host-specific signal during invasion that initiates the resumption of suspended developmental pathways. The resumption of development during infection is analogous to recovery from the facultative arrested dauer stage in the free-living nematode Caenorhabditis elegans. Infective larvae of the canine hookworm Ancylostoma Caninum resume feeding and secrete molecules important for infection when exposed to a host mimicking signal in vitro. This activation process is a model for the initial steps of the infective process. Dauer recovery requires protein synthesis, but not RNA synthesis in C. elegans. To determine the role of RNA and protein synthesis in hookworm infection, inhibitors of RNA and protein synthesis were tested for their effect on feeding and secretion by A. Caninum infective larvae. The RNA synthesis inhibitors α-amanitin and actinomycin D inhibit feeding dose-dependently, with IC50 values of 30 and 8 μM, respectively. The protein synthesis inhibitors puromycin (IC50 = 110 μM), cycloheximide (IC50 = 50 μM), and anisomycin (IC50 = 200 μM) also displayed dose-dependent inhibition of larval feeding. Significant inhibition of feeding by α-amanitin and anisomycin occurred when the inhibitors were added before 12 h of the activation process, but not if the inhibitors were added after 12 h. None of the RNA or protein synthesis inhibitors prevented secretion of the activation-associated protein ASP-1, despite nearly complete inhibition of feeding. The results indicate that unlike dauer recovery in C. elegans, de novo gene expression is required for hookworm larval activation, and the critical genes are expressed within 12 h of exposure to activating stimuli. However, secretion of infection-associated proteins is independent of gene expression, indicating that the proteins are pre-synthesized and stored for rapid release during the initial stages of infection. The genes that are inhibited represent a subset of those required for the transition to parasitism, and therefore represent interesting targets for further investigation. Furthermore, while dauer recovery provides a useful model for hookworm infection, the differences identified here highlight the importance of exercising caution before making generalizations about parasitic nematodes based on C. elegans biology.

  • characterizing Ancylostoma Caninum transcriptome and exploring nematode parasitic adaptation
    BMC Genomics, 2010
    Co-Authors: Zhengyuan Wang, Sahar Abubucker, John Martin, John M. Hawdon, Richard Wilson, Makedonka Mitreva
    Abstract:

    Background Hookworm infection is one of the most important neglected diseases in developing countries, with approximately 1 billion people infected worldwide. To better understand hookworm biology and nematode parasitism, the present study generated a near complete transcriptome of the canine hookworm Ancylostoma Caninum to a very high coverage using high throughput technology, and compared it to those of the free-living nematode Caenorhabditis elegans and the parasite Brugia malayi.

  • characterizing Ancylostoma Caninum transcriptome and exploring nematode parasitic adaptation
    BMC Genomics, 2010
    Co-Authors: Zhengyuan Wang, Sahar Abubucker, John Martin, John M. Hawdon, Richard K Wilson, Makedonka Mitreva
    Abstract:

    Hookworm infection is one of the most important neglected diseases in developing countries, with approximately 1 billion people infected worldwide. To better understand hookworm biology and nematode parasitism, the present study generated a near complete transcriptome of the canine hookworm Ancylostoma Caninum to a very high coverage using high throughput technology, and compared it to those of the free-living nematode Caenorhabditis elegans and the parasite Brugia malayi. The generated transcripts from four developmental stages, infective L3, serum stimulated L3, adult male and adult female, covered 93% of the A. Caninum transcriptome. The broad diversity among nematode transcriptomes was confirmed, and an impact of parasitic adaptation on transcriptome diversity was inferred. Intra-population analysis showed that A. Caninum has higher coding sequence diversity than humans. Examining the developmental expression profiles of A. Caninum revealed major transitions in gene expression from larval stages to adult. Adult males expressed the highest number of selectively expressed genes, but adult female expressed the highest number of selective parasitism-related genes. Genes related to parasitism adaptation and A. Caninum specific genes exhibited more expression selectivity while those conserved in nematodes tend to be consistently expressed. Parasitism related genes were expressed more selectively in adult male and female worms. The comprehensive analysis of digital expression profiles along with transcriptome comparisons enabled identification of a set of parasitism genes encoding secretory proteins in animal parasitic nematode. This study validated the usage of deep sequencing for gene expression profiling. Parasitic adaptation of the canine hookworm is related to its diversity and developmental dynamics. This comprehensive comparative genomic and expression study substantially improves our understanding of the basic biology and parasitism of hookworms and, is expected, in the long run, to accelerate research toward development of vaccines and novel anthelmintics.

  • the canine hookworm genome analysis and classification of Ancylostoma Caninum survey sequences
    Molecular and Biochemical Parasitology, 2008
    Co-Authors: Sahar Abubucker, Kymberlie Hallsworthpepin, John Martin, John M. Hawdon, Yong Yin, Lucinda Fulton, Shiawpyng Yang, Spencer J Johnston, James P Mccarter, Richard Wilson
    Abstract:

    Hookworms infect nearly a billion people. The Ancylostoma Caninum hookworm of canids is a model for studying human infections and information from its genome coupled with functional genomics and proteomics can accelerate progress towards hookworm control. As a step towards a full-scale A. Caninum genome project, we generated 104,000 genome survey sequences (GSSs) and determined the genome size of the canine hookworm. GSSs assembled into 57.6 Mb of unique sequence from a genome that we estimate by flow cytometry of isolated nuclei to be 347±1.2 Mb, substantially larger than other Rhabditina species. Gene finding identified 5,538 genes in the GSS assembly, for a total of 9,113 non-redundant A. Caninum genes when EST sequences are also considered. Functional classifications of many of the 70% of genes with homology to genes in other species are provided based on Gene Ontology and KEGG associations and secreted and membrane-bound proteins are also identified.

Alex Loukas - One of the best experts on this subject based on the ideXlab platform.

  • revisiting the Ancylostoma Caninum secretome provides new information on hookworm host interactions
    Proteomics, 2017
    Co-Authors: Taylor Morante, Alex Loukas, Catherine Shepherd, C C Constantinoiu, Javier Sotillo
    Abstract:

    Hookworm infection is a major tropical parasitic disease affecting almost 500 million people worldwide. These soil-transmitted helminths can survive for many years in the intestine of the host, where they feed on blood, causing iron deficiency anemia and other complications. These parasites release a variety of molecules known as excretory/secretory products (ESPs) that are involved in many different biological processes that govern parasite survival. Using a combination of separation techniques such as SDS-PAGE and OFFGEL electrophoresis, in combination with state-of-the-art mass spectrometry we have reanalyzed the dog hookworm, Ancylostoma Caninum, ESPs (AcESP). We identified 315 proteins present in the AcESP, compared with just 105 identified in previous studies. The most highly represented family of proteins is the SCP/TAPs (110 of the 315 proteins), and the most abundant constituents of AcESP are homologues of the tissue inhibitors of metalloproteases (TIMP) family. Interestingly, we identified new homologs of well-known vaccine candidates and immunomodulatory proteins. This study provides novel information about the proteins secreted by A. Caninum, and constitutes a comprehensive dataset to study the proteins involved in host-hookworm interactions.

  • revisiting the Ancylostoma Caninum secretome provides new information on hookworm host interactions
    bioRxiv, 2017
    Co-Authors: Taylor Morante, Alex Loukas, Catherine Shepherd, C C Constantinoiu, Javier Sotillo
    Abstract:

    Hookworm infection is a major tropical parasitic disease affecting almost 500 million people worldwide. These soil-transmitted helminths can survive for many years in the intestine of the host, where they feed on blood, causing iron deficiency anaemia and other complications. To avoid the host9s immune response the parasite releases excretory/secretory products (ESPs), a complex mixture of glycans, lipids and proteins that represent the major host-parasite interface. Using a combination of separation techniques such as SDS-PAGE and OFFGEL electrophoresis, in combination with state-of-the-art mass spectrometry we have reanalysed the dog hookworm, Ancylostoma Caninum , ESPs (AcES). We identified 315 proteins present in the AcES, compared with just 105 identified in previous studies. The most highly represented family of proteins is the SCP/TAPs (90 of the 315 proteins), and the most abundant constituents of AcES are homologues of the tissue inhibitors of metalloproteases (TIMP) family. We identified putative vaccine candidates and proteins that could have immunomodulatory effects for treating inflammatory diseases. This study provides novel information about the proteins involved in host-hookworm interactions, and constitutes a comprehensive dataset for the development of vaccines and the discovery of new immunoregulatory biologics.

  • changes in protein expression after treatment with Ancylostoma Caninum excretory secretory products in a mouse model of colitis
    Scientific Reports, 2017
    Co-Authors: Javier Sotillo, Thewarach Laha, Alex Loukas, Jeremy Potriquet, Jason Mulvenna, Ivana Ferreira, Severine Navarro
    Abstract:

    Different reports have highlighted the potential use of helminths and their secretions in the treatment of inflammatory bowel disease (IBD) conditions; however, no reports have investigated their effects at a proteome level. Herein, we characterise the protein expression changes that occur in lamina propria (LP) and the intestinal epithelial cells (IEC) of mice with dextran sulfate sodium (DSS)-induced colitis treated with Ancylostoma Caninum excretory/secretory (ES) products using a quantitative proteomic approach. We have shown how parasite products can significantly alter the expression of proteins involved in immune responses, cell death and with an antioxidant activity. Interestingly, significant changes in the expression levels of different mucins were observed in this study. MUC13, a mucin implicated in gastrointestinal homeostasis, was upregulated in the LP of mice with DSS-induced colitis treated with ES, while MUC2, a major component of mucus, was upregulated in the IEC. In addition, A. Caninum proteins have an important effect on proteins with antioxidant functions and proteins involved in intestinal homeostasis and tissue integrity and regeneration. Understanding how parasites can ameliorate IBD pathogenesis can help us design novel treatments for autoimmune diseases.

  • molecular cloning and characterization of ac mtp 2 an astacin like metalloprotease released by adult Ancylostoma Caninum
    Molecular and Biochemical Parasitology, 2007
    Co-Authors: Jianjun Feng, Bin Zhan, Alex Loukas, Yueyuan Liu, Angela L. Williamson, Gaddam Goud, Sen Liu, Peter J. Hotez
    Abstract:

    Ac-MTP-2 is an astacin-like metalloprotease secreted by adult Ancylostoma Caninum hookworms. Ac-mtp-2 cDNA was cloned by immunoscreening a cDNA library with antisera prepared against adult A. Caninum excretory/secretory (ES) products. The full-length Ac-mtp-2 contains 850 bp cDNA encoding a 233 amino acid open reading frame (ORF) with 32% amino acid identity to Ce-NSP-4, a pharyngeal cell-derived secreted metalloprotease of the nematode Caenorhabditis elegans. The predicted ORF contained a conserved Met-turn sequence (SXMHY), but only a partial zinc-binding signature sequence (GXXXEHXRXER instead of HEXXHXXGXXHEXXRXDR) found in other astacins. However, by both gelatin gel electrophoresis and azocasein digestion, the recombinant Ac-MTP-2 exhibited proteolytic activity that was inhibited by the zinc chelator 1,10-phenanthroline and Ac-TMP, a putative tissue inhibitor of metalloprotease that was previously shown to be a highly abundant component of adult A. Caninum ES products. By RT-PCR, Western blot Ac-MTP-2 was found only expressed in adult hookworms and secreted in the adult ES products. Immunolocalization with antisera shows that Ac-MTP-2 is located to the esophageal glands (confirming its role as a secretory protein), as well as to the parasite uterus. It is hypothesized that Ac-MTP-2 functions in the extracorporeal digestion of the intestinal mucosal plug lodged in the buccal capsule of the adult parasite.

  • saposin like proteins from the intestine of the blood feeding hookworm Ancylostoma Caninum
    Parasitology, 2007
    Co-Authors: Tegan A Don, Yelena Oksov, Sara Lustigman, Alex Loukas
    Abstract:

    Hookworms feed on blood, utilizing haemoglobin for nutrition, growth and reproduction. The haemoglobin digestion cascade has been partially elucidated, but the process immediately preceding this event, haemolysis, has received considerably less attention. We have cloned and expressed Ancylostoma Caninum mRNAs encoding 2 proteins belonging to the saposin-like protein (SAPLIP) family, termed Ac-slp-1 and Ac-slp-2. The open reading frames of SLP-1 and SLP-2were used to identify expressed sequence tags encoding SAPLIPs from the 4 major clades of animal parasitic nematodes. Both Ac-slp-1 and s1p-2 mRNAs were shown to be expressed in all life stages assessed, with slp-1 predominantly being expressed in third-stage larvae (L3) before and after activation with dog serum. Recombinant SLP-1 and SLP-2 were expressed in insect cells and used to raise specific antisera in mice. These antisera were used as probes in fluorescence microscopy to localize the anatomic expression sites of both proteins to small, punctate organelles or vesicles within the intestinal cells of adult worms; weak staining was detected on the microvillar brush border of the intestine. Using transmission electron microscopy, both proteins were localized to similar vesicles in the intestinal cells of the L3. Recombinant proteins contained C-terminal purification tags that potentially precluded dimerization and possibly interfered with the subsequent detection of haemolytic activity. Their expression in the gut of the L3 and adult stages suggests a role for these hookworm SAPLIPs in the lysis of host cells during tissue migration and/or feeding.

Paul Prociv - One of the best experts on this subject based on the ideXlab platform.

  • experimental human infection with the dog hookworm Ancylostoma Caninum
    The Medical Journal of Australia, 2003
    Co-Authors: J K Landmann, Paul Prociv
    Abstract:

    Objective: To investigate possible routes for human infection by the dog hookworm (Ancylostoma Caninum). Design, setting and participant. Relatively small numbers of infective larvae were administered orally and percutaneously to an informed healthy volunteer (J K L) under medical supervision, at intervals between May 1998 and May 1999. Main outcome measures: Symptoms; weekly blood eosinophil counts; faecal microscopy. Results: A marked blood eosinophilia followed a single oral exposure to 100 infective larvae, while faecal examination remained negative. Eosinophil counts then declined gradually, although a rapid, spontaneous rise several months later, at the beginning of spring, possibly indicated reactivation of dormant larvae. Blood eosinophil numbers did not rise significantly after percutaneous infection with 200 larvae. A subsequent, smaller, oral inoculum of 20 larvae provoked an eosinophil response similar to that of the first experiment. Conclusions: Our findings suggest that, following ingestion, some infective larvae of A. Caninum develop directly into adult worms in the human gut (as they do in dogs). While the percutaneous route might be the most common means of human exposure to canine hookworm larvae, leading generally to subclinical infection, oral infection may be more likely to provoke symptomatic eosinophilic enteritis.

  • Giardia trophozoites in dog hookworm, Ancylostoma Caninum: accident or hyperparasitism?
    Acta Tropica, 2001
    Co-Authors: Lauren Rebecca Ranford, Malcolm K. Jones, Paul Prociv
    Abstract:

    During the course of transmission electron microscopic studies of adult Ancylostoma Caninum removed from a dog, several Giardia trophozoites were found in sections of the buccal cavity, oesophagus and intestine of several hookworms. Although the protozoa appeared viable, this unusual finding probably represents accidental uptake by, rather than an established infection of, the hookworm. It is feasible, however, that the trophozoites might have survived and even multiplied in this aberrant site.

  • purification of a diagnostic secreted cysteine protease like protein from the hookworm Ancylostoma Caninum
    Parasitology International, 2000
    Co-Authors: Alex Loukas, Paul J. Brindley, Paul Prociv, Andrew J Dowd
    Abstract:

    The enteric infection of humans with the canine hookworm Ancylostoma Caninum varies in its clinical presentation, ranging from asymptomatic to eosinophilic gastroenteritis requiring surgical intervention. Infections are not patent, but can be diagnosed immunologically by detecting antibodies to an immunodominant secreted hookworm protein termed Ac68. To characterise Ac68, we purified the native protein from A. Caninum excretory/secretory products using size exclusion followed by anion exchange chromatography. The epitopes in the purified protein recognised by human infection sera were shown to be proteins and not carbohydrates. The N-terminal amino acid sequence of the purified Ac68 was determined and six of the 11 residues obtained were shared with a previously characterised cysteine protease of A. Caninum, AcCP1.

  • acasp a gene encoding a cathepsin d like aspartic protease from the hookworm Ancylostoma Caninum
    Biochemical and Biophysical Research Communications, 1996
    Co-Authors: Stephen A Harrop, Paul Prociv, Paul J. Brindley
    Abstract:

    Abstract Intestinal infection with the zoonotic hookworm Ancylostoma Caninum can provoke human eosinophilic enteritis. A cDNA was isolated from A. Caninum, using an oligonucleotide primer designed to hybridize to the region encoding the consensus, catalytic site residues D 32 TGSSNLW of aspartic proteases. This novel cDNA encoded an aspartic protease zymogen of 422 amino acids, exhibiting 47% identity to the lysosomal aspartic protease of Aedes aegypti, 46% identity to the aspartic protease of Schistosoma japonicum, and 48.5% to human cathepsin D. Its deduced structure differed from that of cathepsin D in the loop 2 “flap,” which holds the substrate at the active site, and by the presence of a COOH-terminal extension of ∼30 residues.

  • human enteric infection with Ancylostoma Caninum hookworms reappraised in the light of a new zoonosis
    Acta Tropica, 1996
    Co-Authors: Paul Prociv, John Croese
    Abstract:

    Recent studies in northeastern Australia indicate that enteric infection with Ancylostoma Caninum is a leading cause of human eosinophilic enteritis. Much more frequent accompaniments of this infection are obscure abdominal pain with or without blood eosinophilia, while a large part of the population is probably infected asymptomatically. These conclusions are based on extensive serological investigations in patients and control subjects, as well as 15 cases in which single, adult hookworms were identified in situ in patients. In no case has more than one worm been identified, and none has been fully mature, so the infections have never been patent. Aphthous ulcers of the terminal ileum, caecum and colon have been seen in association with this infection and have also been observed in almost 5% of patients who are colonoscoped in north Queensland. Serodiagnosis has relied on an IgG and IgE ELISA using excretory-secretory antigens from adult A. Caninum, but Western blot using these antigens to identify IgG4 antibodies to a protein of molecular weight 68 kDa (Ac68) promises to be more specific and sensitive. However, identical antigens appear to be secreted by the anthropophilic hookworms as well. The clinical, public health and biological significance of these findings are discussed in detail.

Ray M Kaplan - One of the best experts on this subject based on the ideXlab platform.

  • multiple drug resistance in the canine hookworm Ancylostoma Caninum an emerging threat
    Parasites & Vectors, 2019
    Co-Authors: Pablo David Jimenez Castro, Sue B Howell, John J Schaefer, Russell W Avramenko, John S Gilleard, Ray M Kaplan
    Abstract:

    Background The canine hookworm, Ancylostoma Caninum is the most prevalent and important intestinal nematode parasite of dogs in the USA. Hookworms are typically well controlled by treatment with all commonly used anthelmintics that are approved for this use in dogs. However, in the past few years, cases of recurrent/persistent canine hookworm infections appear to have dramatically increased, suggesting that anthelmintic resistance (AR) may have evolved in this parasite. These cases are highly overrepresented by greyhounds, but multiple other breeds are also represented. The aim of this study was to characterize several of these suspected resistant isolates using in vitro, genetic and clinical testing to determine if these cases represent true anthelmintic resistance in A. Caninum.

  • multiple drug resistance in the canine hookworm Ancylostoma Caninum an emerging threat
    bioRxiv, 2019
    Co-Authors: Pablo David Jimenez Castro, Sue B Howell, John J Schaefer, Russell W Avramenko, John S Gilleard, Ray M Kaplan
    Abstract:

    In the past few years, diagnoses by veterinarians of recurrent canine hookworm infections have dramatically increased, suggesting that anthelmintic resistance (AR) may have evolved in the parasite Ancylostoma Caninum. To investigate this, we established three suspected-resistant and two susceptible A. Caninum isolates in research dogs for further study. The egg hatch assay (EHA) and the larval development assay (LDA) were used for detecting resistance to benzimidazoles, and macrocyclic lactones, respectively. Resistance ratios ranged from 6.0 to >100 and 5.5 to 69.8 for the EHA and LDA, respectively. Following treatments with fenbendazole, pyrantel and milbemycin oxime, reduction in fecal egg counts ranged from 64 to 86%, 0 to 2% and 58 to 92%, respectively. Deep amplicon sequencing of the isotype-1 beta-tubulin gene identified a high frequency of resistance-associated single nucleotide polymorphisms at codon 167 in the resistant isolates and clinical cases. These data conclusively demonstrate multiple anthelmintic resistance in A. Caninum, and provide pivotal evidence that this is an emerging problem in the United States. Consequently, these findings should provide some concern to the global health community, as the scale-up of mass drug administration for soil-transmitted helminths (STH) is now placing similar selection pressures for benzimidazole resistance in human hookworms.

  • multiple drug resistance in the canine hookworm Ancylostoma Caninum an emerging threat
    bioRxiv, 2019
    Co-Authors: Pablo David Jimenez Castro, Sue B Howell, John J Schaefer, Russell W Avramenko, John S Gilleard, Ray M Kaplan
    Abstract:

    Abstract In the past few years, diagnoses by veterinarians of recurrent canine hookworm infections have dramatically increased, suggesting that anthelmintic resistance (AR) may have evolved in the parasite Ancylostoma Caninum. To investigate this, we established three “suspected-resistant” and two susceptible A. Caninum isolates in research dogs for further study. The egg hatch assay (EHA) and the larval development assay (LDA) were used for detecting resistance to benzimidazoles, and macrocyclic lactones, respectively. Resistance ratios ranged from 6.0 to >100 and 5.5-69.8 for the EHA and LDA, respectively. Following treatments with fenbendazole, pyrantel and milbemycin oxime, reduction in faecal egg counts ranged from 64–86%, 0–72% and 58–92%, respectively. Deep amplicon sequencing of the isotype-1 β tubulin gene identified a high frequency of resistance-associated single nucleotide polymorphisms at codon 167 in the resistant isolates and clinical cases.. These data conclusively demonstrate multiple anthelmintic resistance in A. Caninum, and provide pivotal evidence that this is an emerging problem in the United States. Consequently, these findings should provide some concern to the global health community, as the scale-up of mass drug administration for soil-transmitted helminths (STH) is now placing similar selection pressures for benzimidazole resistance in human hookworms.

  • real time pcr assays for monitoring benzimidazole resistance associated mutations in Ancylostoma Caninum
    Experimental Parasitology, 2009
    Co-Authors: Jan M Schwenkenbecher, Ray M Kaplan
    Abstract:

    Frequent and broad application of anthelmintic drugs for treatment of intestinal parasite infection has led to drug resistance that often renders whole populations of livestock unresponsive to treatment. Therefore, it is important to detect mutations associated with drug resistance before it becomes clinically manifest. To monitor developing drug resistance against benzimidazoles (BZ), we developed real-time PCR assays and applied them to analyse the beta-tubulin isotype-1 gene of the hookworm Ancylostoma Caninum, an important parasite of dogs. Previously, we developed PCR assays to monitor codon positions 167 and 200. Here, we describe an assay which is able to detect resistance alleles in codon 198. These real-time PCR assays were subsequently applied to screen hookworm specimens recovered from dogs in Georgia. No elevated levels of polymorphisms at the investigated loci were found, suggesting that selection for resistance in the tested samples did not occur.

  • development and characterization of microsatellite markers for the canine hookworm Ancylostoma Caninum
    Parasitology Research, 2007
    Co-Authors: J M Schwenkenbecher, Ray M Kaplan
    Abstract:

    Microsatellites are repetitive genomic elements that show high levels of variation and therefore provide excellent tools to study the genetics of eukaryotic organisms. Hookworms are extremely common and important nematode parasites of humans and animals, causing potentially serious disease morbidity. Control of hookworms in dogs is achieved by frequent treatment with anthelmintics, and in humans, anthelmintics are frequently administered in a mass-treatment community-wide approach. Understanding the population genetics of hookworms has important implications for studies on the development and spread of drug resistance. We investigated the genome of Ancylostoma Caninum for microsatellites by developing and then screening an enriched genomic library as well as by data mining published sequences of a whole genome shotgun library. Investigations revealed a high abundance of trinucleotide repeats. Dinucleotide repeats were characterized by a high number of AT, GA, and GT repeats. After testing and optimization of 68 markers, a panel of 34 polymorphic microsatellite markers were selected. Microsatellite analysis of hookworm isolates revealed a high degree of polymorphism, which was not influenced by the length of the repeats. This panel of microsatellite markers makes it possible to pursue investigations on the population genetics of A. Caninum. Furthermore, a number of the markers demonstrated suitability for analysis of the human hookworm species Necator americanus and A. duodenale.