Soil-transmitted nematodes (STNs) place a tremendous burden on health and economics worldwide wit... more Soil-transmitted nematodes (STNs) place a tremendous burden on health and economics worldwide with an estimate of at least 1.5 billion people, or 24% of the population, being infected with at least 1 STN globally. Children and pregnant women carry the heavier pathological burden, and disease caused by the blood-feeding worm in the intestine can result in anaemia and delays in physical and intellectual development. These parasites are capable of infecting and reproducing in various host species, but what determines host specificity remains unanswered. Identifying the molecular determinants of host specificity would provide a crucial breakthrough towards understanding the biology of parasitism and could provide attractive targets for intervention. To investigate specificity mechanisms, members of the hookworm genus Ancylostoma provide a powerful system as they range from strict specialists to generalists. Using transcriptomics, differentially expressed genes (DEGs) in permissive (hams...
Teaching biology laboratories remotely presents unique problems and challenges for instructors. M... more Teaching biology laboratories remotely presents unique problems and challenges for instructors. Microscopic examination of specimens, as is common in parasitology labs, is especially difficult given the limited quantity of teaching specimens and the need for each student to have access to a microscope at their remote location. Observing images of parasites on the internet coupled with written exercises, while useful, is unrepresentative of real-world laboratory or field conditions. To provide a more realistic microscopy-centered synchronous experience for our parasitology class during the coronavirus pandemic, we used a smartphone mounted on a student microscope to livestream examination of parasite specimens to remote students via the Webex meeting app. This allowed two instructors, working from separate locations, to present and narrate the view of the specimens through the microscope in real time to the remotely located class. While less than ideal, livestreaming microscopic view...
Full list of author information is available at the end of the articleelements. Aca-snr-3 encodes... more Full list of author information is available at the end of the articleelements. Aca-snr-3 encodes a core small nuclear ribonucleoprotein, and Aca-lpp-1 encodes a lipid phosphate phosphohydrolase. Expression of both genes peaked at the late L4 stage, suggesting a role in L4 development. The 3′-terminal genomic fragment of the snr-3 gene displayed Ac-DAF-16-dependent cis-regulatory activity.
Current Topics in Microbiology and Immunology, 2021
In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establ... more In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establishing a controlled human hookworm infection (CHHI) model in non-endemic and endemic geographical regions, to facilitate a pathway towards accelerated vaccine development. The success achieved in establishing the CHHI platform specifically allows the Human Hookworm Vaccine Initiative (HHVI) to accelerate its progress by establishing a human hookworm vaccination/challenge model (HVCM) in a hookworm endemic area of Brazil. The HVCM will permit the rapid and robust determination of clinical efficacy in adults, allowing for early selection of the most efficacious human hookworm vaccine (HHV) candidate(s) to advance into later-stage pivotal paediatric clinical trials and reduce the overall number of participants required to assess efficacy (Diemert et al. 2018).
Current Topics in Microbiology and Immunology, 2021
In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establ... more In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establishing a controlled human hookworm infection (CHHI) model in non-endemic and endemic geographical regions, to facilitate a pathway towards accelerated vaccine development. The success achieved in establishing the CHHI platform specifically allows the Human Hookworm Vaccine Initiative (HHVI) to accelerate its progress by establishing a human hookworm vaccination/challenge model (HVCM) in a hookworm endemic area of Brazil. The HVCM will permit the rapid and robust determination of clinical efficacy in adults, allowing for early selection of the most efficacious human hookworm vaccine (HHV) candidate(s) to advance into later-stage pivotal paediatric clinical trials and reduce the overall number of participants required to assess efficacy (Diemert et al. 2018).
Insect pathogens have adopted an array of mechanisms to subvert the immune pathways of their resp... more Insect pathogens have adopted an array of mechanisms to subvert the immune pathways of their respective hosts. Suppression may occur directly at the level of host–pathogen interactions, for instance phagocytic capacity or phenoloxidase activation, or at the upstream signaling pathways that regulate these immune effectors. Insect pathogens of the family Baculoviridae, for example, are known to produce a UDP-glycosyltransferase (UGT) that negatively regulates ecdysone signaling. Normally, ecdysone positively regulates both molting and antimicrobial peptide production, so the inactivation of ecdysone by glycosylation results in a failure of host larvae to molt, and probably a reduced antimicrobial response. Here, we examine a putative ecdysteroid glycosyltransferase, Hba_07292 (Hb-ugt-1), which was previously identified in the hemolymph-activated transcriptome of the entomopathogenic nematode Heterorhabditis bacteriophora. Injection of recombinant Hb-ugt-1 (rHb-ugt-1) into Drosophila m...
It is with great pleasure that I introduce this year’s winner of the Bueding and von Brand Lectur... more It is with great pleasure that I introduce this year’s winner of the Bueding and von Brand Lectureship award, Dr. James ‘‘Sparky’’ Lok. This Lectureship ‘‘honors someone who has made major research contributions to the field of biochemistry, molecular biology, and/or pharmacology of parasitic helminths.’’ As will soon become apparent, Sparky truly deserves this honor for his landmark advances in parasitic nematode molecular biology. I first met Sparky more than 30 years ago, when I was a graduate student at the University of Pennsylvania, where he was a faculty member in the parasitology group. As 1 of only 2 faculty members studying nematodes (the other being my mentor Gerry Schad), Sparky was both a source of information and inspiration, as well as a member of my committee. He was also somewhat of an enigma. He occupied a lab in a distant part of the sprawling veterinary school complex, far from the rest of the group, so chance encounters were rare. In short, it took a special trip to see Sparky. Consequently, we students did not know as much about him as some of the other professors. For example, one longstanding area of speculation among my graduate student cohort was the origin of the nickname Sparky. We imagined that it referred to his laid-back manner, similar to how someone might call a tall person ‘‘Shorty.’’ Another hypothesis was that an unfortunate chemistry class incident led to the nickname. But for as long as I have known him, he always introduced himself as Sparky, so he obviously wasn’t trying to cover up an embarrassing historical event. Recently I learned the true origin of his nickname. I have it from a good source (his lovely wife Maureen), that the moniker derives from a 1950s radio show that his father loved to listen to, called Big John and Sparky. His father started calling him ‘‘Sparky’’ as a baby, and it stuck. Sparky grew up in Mississippi and went to the University of Southern Mississippi in Hattiesburg, where he graduated in 1975 with a BS in biology. During college he played saxophone in the Howlers, a blues band that specialized in fraternity parties. Sparky left USM and a future in music in 1975 to pursue his graduate career at Cornell. After earning his M.S. and Ph.D. in entomology at Cornell, Sparky took a post-doctoral position at the University of Pennsylvania with Bob Grieve studying filarid nematodes and their insect hosts. After his post-doc and a year as a research scientist, Sparky was appointed assistant professor of parasitology at Penn. He continued investigating filarid biology into the late 1990s, when he began collaborating with Dr. Schad to study Strongyloides. He soon made the risky move of switching his lab to investigate signaling pathways during infection in these nematodes. This led to his pioneering work in helminth molecular biology, for which he is honored today. Sparky was the first researcher to perform germline transgenesis in a parasitic nematode, Strongyloides stercoralis. Heritable transgenesis, or the ability to insert and express foreign DNA in an organism, is a foundational molecular technique, one that is required to truly understand gene function and molecular mechanisms. Parasitic nematodes are notoriously difficult to transform, and until Sparky, no one had reported successful germline transgenesis in one. Sparky took advantage of the free-living heterogonic generation of Strongyloides, which is amenable to cultivation on agar plates. This provides access to free living females, whose gonad can be microinjected with foreign DNA. Sparky’s group painstakingly conquered the problems of transgene array silencing and the obligate need for a subsequent host passage. He developed the first transgenic ‘‘toolkit’’ for a parasitic nematode, including tissue specific promoters, reporter constructs, and piggyBac transposon technology. He next used these tools to confirm the role of the transcription factor DAF-16, the PI3-Kinase AGE-1, and G protein coupled receptor signaling in activation and infection by Strongyloides infective L3, thereby lending further support for the dauer hypothesis of parasitic nematode infection. Sparky’s trail blazing work helped me immensely by informing my investigations of similar pathways involved in hookworm infection. Recently, his group published proof-of-principle for CRISPR/ Cas9 as a gene-editing tool for Strongyloides. This represents the first report of successful genome editing using this technique in a parasitic nematode and adds to his contributions on the cutting edge of nematode molecular biology. One of his recommenders for this award encapsulated this contribution best:
Background Hookworm infection is one of the most important neglected diseases in developing count... more 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. Results 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 i...
Parasitic nematodes constitute one of the major threats to human health, causing diseases of majo... more Parasitic nematodes constitute one of the major threats to human health, causing diseases of major socioeconomic importance worldwide. Recent estimates indicate that more than 1 billion people are infected with parasitic nematodes around the world. Current measures to combat parasitic nematode infections include anthelmintic drugs. However, heavy exposure to anthelmintics has selected populations of livestock parasitic nematodes that are no longer susceptible to the drugs, rendering several anthelmintics useless for parasitic nematode control in many areas of the world. The rapidity with which anthelmintic resistance developed in response to these drugs suggests that increasing the selective pressure on human parasitic nematodes will also rapidly generate resistant worm populations. Therefore, development of new anthelmintics is of major importance before resistance becomes widespread in human parasitic nematode populations. G-Protein Coupled Receptors (GPCRs) represent an important...
Soil-transmitted nematodes (STNs) place a tremendous burden on health and economics worldwide wit... more Soil-transmitted nematodes (STNs) place a tremendous burden on health and economics worldwide with an estimate of at least 1.5 billion people, or 24% of the population, being infected with at least 1 STN globally. Children and pregnant women carry the heavier pathological burden, and disease caused by the blood-feeding worm in the intestine can result in anaemia and delays in physical and intellectual development. These parasites are capable of infecting and reproducing in various host species, but what determines host specificity remains unanswered. Identifying the molecular determinants of host specificity would provide a crucial breakthrough towards understanding the biology of parasitism and could provide attractive targets for intervention. To investigate specificity mechanisms, members of the hookworm genus Ancylostoma provide a powerful system as they range from strict specialists to generalists. Using transcriptomics, differentially expressed genes (DEGs) in permissive (hams...
Teaching biology laboratories remotely presents unique problems and challenges for instructors. M... more Teaching biology laboratories remotely presents unique problems and challenges for instructors. Microscopic examination of specimens, as is common in parasitology labs, is especially difficult given the limited quantity of teaching specimens and the need for each student to have access to a microscope at their remote location. Observing images of parasites on the internet coupled with written exercises, while useful, is unrepresentative of real-world laboratory or field conditions. To provide a more realistic microscopy-centered synchronous experience for our parasitology class during the coronavirus pandemic, we used a smartphone mounted on a student microscope to livestream examination of parasite specimens to remote students via the Webex meeting app. This allowed two instructors, working from separate locations, to present and narrate the view of the specimens through the microscope in real time to the remotely located class. While less than ideal, livestreaming microscopic view...
Full list of author information is available at the end of the articleelements. Aca-snr-3 encodes... more Full list of author information is available at the end of the articleelements. Aca-snr-3 encodes a core small nuclear ribonucleoprotein, and Aca-lpp-1 encodes a lipid phosphate phosphohydrolase. Expression of both genes peaked at the late L4 stage, suggesting a role in L4 development. The 3′-terminal genomic fragment of the snr-3 gene displayed Ac-DAF-16-dependent cis-regulatory activity.
Current Topics in Microbiology and Immunology, 2021
In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establ... more In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establishing a controlled human hookworm infection (CHHI) model in non-endemic and endemic geographical regions, to facilitate a pathway towards accelerated vaccine development. The success achieved in establishing the CHHI platform specifically allows the Human Hookworm Vaccine Initiative (HHVI) to accelerate its progress by establishing a human hookworm vaccination/challenge model (HVCM) in a hookworm endemic area of Brazil. The HVCM will permit the rapid and robust determination of clinical efficacy in adults, allowing for early selection of the most efficacious human hookworm vaccine (HHV) candidate(s) to advance into later-stage pivotal paediatric clinical trials and reduce the overall number of participants required to assess efficacy (Diemert et al. 2018).
Current Topics in Microbiology and Immunology, 2021
In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establ... more In this chapter, we describe the scientific, technical, clinical and regulatory aspects of establishing a controlled human hookworm infection (CHHI) model in non-endemic and endemic geographical regions, to facilitate a pathway towards accelerated vaccine development. The success achieved in establishing the CHHI platform specifically allows the Human Hookworm Vaccine Initiative (HHVI) to accelerate its progress by establishing a human hookworm vaccination/challenge model (HVCM) in a hookworm endemic area of Brazil. The HVCM will permit the rapid and robust determination of clinical efficacy in adults, allowing for early selection of the most efficacious human hookworm vaccine (HHV) candidate(s) to advance into later-stage pivotal paediatric clinical trials and reduce the overall number of participants required to assess efficacy (Diemert et al. 2018).
Insect pathogens have adopted an array of mechanisms to subvert the immune pathways of their resp... more Insect pathogens have adopted an array of mechanisms to subvert the immune pathways of their respective hosts. Suppression may occur directly at the level of host–pathogen interactions, for instance phagocytic capacity or phenoloxidase activation, or at the upstream signaling pathways that regulate these immune effectors. Insect pathogens of the family Baculoviridae, for example, are known to produce a UDP-glycosyltransferase (UGT) that negatively regulates ecdysone signaling. Normally, ecdysone positively regulates both molting and antimicrobial peptide production, so the inactivation of ecdysone by glycosylation results in a failure of host larvae to molt, and probably a reduced antimicrobial response. Here, we examine a putative ecdysteroid glycosyltransferase, Hba_07292 (Hb-ugt-1), which was previously identified in the hemolymph-activated transcriptome of the entomopathogenic nematode Heterorhabditis bacteriophora. Injection of recombinant Hb-ugt-1 (rHb-ugt-1) into Drosophila m...
It is with great pleasure that I introduce this year’s winner of the Bueding and von Brand Lectur... more It is with great pleasure that I introduce this year’s winner of the Bueding and von Brand Lectureship award, Dr. James ‘‘Sparky’’ Lok. This Lectureship ‘‘honors someone who has made major research contributions to the field of biochemistry, molecular biology, and/or pharmacology of parasitic helminths.’’ As will soon become apparent, Sparky truly deserves this honor for his landmark advances in parasitic nematode molecular biology. I first met Sparky more than 30 years ago, when I was a graduate student at the University of Pennsylvania, where he was a faculty member in the parasitology group. As 1 of only 2 faculty members studying nematodes (the other being my mentor Gerry Schad), Sparky was both a source of information and inspiration, as well as a member of my committee. He was also somewhat of an enigma. He occupied a lab in a distant part of the sprawling veterinary school complex, far from the rest of the group, so chance encounters were rare. In short, it took a special trip to see Sparky. Consequently, we students did not know as much about him as some of the other professors. For example, one longstanding area of speculation among my graduate student cohort was the origin of the nickname Sparky. We imagined that it referred to his laid-back manner, similar to how someone might call a tall person ‘‘Shorty.’’ Another hypothesis was that an unfortunate chemistry class incident led to the nickname. But for as long as I have known him, he always introduced himself as Sparky, so he obviously wasn’t trying to cover up an embarrassing historical event. Recently I learned the true origin of his nickname. I have it from a good source (his lovely wife Maureen), that the moniker derives from a 1950s radio show that his father loved to listen to, called Big John and Sparky. His father started calling him ‘‘Sparky’’ as a baby, and it stuck. Sparky grew up in Mississippi and went to the University of Southern Mississippi in Hattiesburg, where he graduated in 1975 with a BS in biology. During college he played saxophone in the Howlers, a blues band that specialized in fraternity parties. Sparky left USM and a future in music in 1975 to pursue his graduate career at Cornell. After earning his M.S. and Ph.D. in entomology at Cornell, Sparky took a post-doctoral position at the University of Pennsylvania with Bob Grieve studying filarid nematodes and their insect hosts. After his post-doc and a year as a research scientist, Sparky was appointed assistant professor of parasitology at Penn. He continued investigating filarid biology into the late 1990s, when he began collaborating with Dr. Schad to study Strongyloides. He soon made the risky move of switching his lab to investigate signaling pathways during infection in these nematodes. This led to his pioneering work in helminth molecular biology, for which he is honored today. Sparky was the first researcher to perform germline transgenesis in a parasitic nematode, Strongyloides stercoralis. Heritable transgenesis, or the ability to insert and express foreign DNA in an organism, is a foundational molecular technique, one that is required to truly understand gene function and molecular mechanisms. Parasitic nematodes are notoriously difficult to transform, and until Sparky, no one had reported successful germline transgenesis in one. Sparky took advantage of the free-living heterogonic generation of Strongyloides, which is amenable to cultivation on agar plates. This provides access to free living females, whose gonad can be microinjected with foreign DNA. Sparky’s group painstakingly conquered the problems of transgene array silencing and the obligate need for a subsequent host passage. He developed the first transgenic ‘‘toolkit’’ for a parasitic nematode, including tissue specific promoters, reporter constructs, and piggyBac transposon technology. He next used these tools to confirm the role of the transcription factor DAF-16, the PI3-Kinase AGE-1, and G protein coupled receptor signaling in activation and infection by Strongyloides infective L3, thereby lending further support for the dauer hypothesis of parasitic nematode infection. Sparky’s trail blazing work helped me immensely by informing my investigations of similar pathways involved in hookworm infection. Recently, his group published proof-of-principle for CRISPR/ Cas9 as a gene-editing tool for Strongyloides. This represents the first report of successful genome editing using this technique in a parasitic nematode and adds to his contributions on the cutting edge of nematode molecular biology. One of his recommenders for this award encapsulated this contribution best:
Background Hookworm infection is one of the most important neglected diseases in developing count... more 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. Results 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 i...
Parasitic nematodes constitute one of the major threats to human health, causing diseases of majo... more Parasitic nematodes constitute one of the major threats to human health, causing diseases of major socioeconomic importance worldwide. Recent estimates indicate that more than 1 billion people are infected with parasitic nematodes around the world. Current measures to combat parasitic nematode infections include anthelmintic drugs. However, heavy exposure to anthelmintics has selected populations of livestock parasitic nematodes that are no longer susceptible to the drugs, rendering several anthelmintics useless for parasitic nematode control in many areas of the world. The rapidity with which anthelmintic resistance developed in response to these drugs suggests that increasing the selective pressure on human parasitic nematodes will also rapidly generate resistant worm populations. Therefore, development of new anthelmintics is of major importance before resistance becomes widespread in human parasitic nematode populations. G-Protein Coupled Receptors (GPCRs) represent an important...
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