OSMAC (one strain many compounds) provides a convenient strategy to produce chemically diverse and novel natural products. In the study, the application of an OSMAC approach on a fungus Penicillium citrinum YSC-1 isolated from a medicinal plant Chloranthus japonicus, using different culture media, led to the isolation and identification of seven new spirooxindole alkaloids penicitrimicins A-G (1-7) with a rare 6/5/5/6/6 polycyclic skeleton, along with two known compounds (8-9). The new structures were characterized based on the comprehensive spectroscopic analyses, including 1D, 2D NMR and HRESIMS data. The absolute configurations of compounds 1-7 were determined by modified Mosher ester methodology, PGME derivatization, X-ray crystallographic analysis, and quantum chemical calculations. Biological evaluation revealed that these spirooxindole alkaloids exhibited good biocompatibility (<5 % hemolysis and > 80 % cell viability) while displaying obvious antimalarial activity against Plasmodium falciparum Dd2 strain, with EC50 values spanning 0.9-2.4 μM. Furthermore, stage-specific assays revealed that compound 5 displayed significant inhibitory effects on the developmental transition of asexual blood-stage parasites, effectively blocking their progression to subsequent lifecycle stages.
Parasites of the genus Cryptosporidium have evolved to have a highly compact genome of ∼9.1 Mb. The mechanisms that regulate gene expression in Cryptosporidium spp. remain incompletely understood at all levels, including chromatin accessibility, transcription factor activation and repression and RNA processing. This review discusses possible mechanisms of gene regulation in Cryptosporidium spp., including histone modifications, cis regulatory elements, transcription factors and non-coding RNAs. Cryptosporidium spp. are among the most basal branching apicomplexans and existing evidence suggests that they diverge from other members of their phylum via retention of the E2F/DP1 transcription factor family, and the recent discovery that C. parvum produces polycistronic transcripts. Most of what we know about gene regulation in the genus Cryptosporidium is based on sequence conservation and homology with other members of the phylum Apicomplexa, and in some cases, more distant eukaryotes. Very few putative gene regulatory components identified in Cryptosporidium spp. are supported by experimental confirmation. This review summarizes what we know about gene regulation in Cryptosporidium spp. and identifies gaps in our current understanding.
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UGA biochemists create new tool to study biological process in parasites
Researchers in the West Laboratory are interested in how unicellular parasites thrive in their environments. Focusing on post-translational modifications of proteins, particularly a crucial process called glycosylation, researchers are gaining insights into how this basic life process in parasites can lead to better treatments for diseases. Read more.
CTEGD faculty member Jessica Kissinger earned the distinction of University Professor, a title bestowed on those who have made a significant impact on the university in addition to fulfilling their regular academic responsibilities. Read more
Diagnosing Chagas is complicated — in both people and canines. False negatives aren’t unheard of, leading people to not know they or their pets are infected. And that delays treatment. Read more.
Researchers at the University of Georgia’s Center for Tropical and Emerging Global Diseases have developed the first test to determine whether treatment for Chagas disease was effective. Read more.
Chester Joyner, assistant professor in the College of Veterinary Medicine’s infectious diseases department and member of CTEGD, is integrating molecular biology, immunology and vaccine development to develop new therapies needed to treat and prevent malaria. Read more.
Every year, malaria evades the immune defenses of nearly 250 million people. But Samarchith “Sam” Kurup is determined to outsmart the parasite before it strikes. Read more.
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Hilary Danz took a new position at Sanofi. She is now the mRNA Center of Excellence New Vaccine Research Lead.
Mattie Pawlowic was awarded a Career Development Award from Wellcome Trust in March.
Justin Widener has left Boehringer Ingelheim and is now at Elano Animal Health.
Nuria Negrao was interviewed by the Northern California Chapter of the American Medical Writers Association.
Vivian Padin-Irizarry has been promoted to Associate Professor of Biology with tenure at Clayton State University.
Nathan Chasen has recently accepted an Assistant Professor position at the University of South Alabama.
Alona Botnar is now the Associate Director of International Market Access – Oncology Pipeline at AbbVie.
Hyun Woo (John) Kim started a new position at Helix Biostructures.
Congratulations, new graduates!
Katherine Moen (Moreno Lab) Megna Tiwari (West Lab)
Trainee News
Clyde Schmidt (Kurup Lab) won the award for Outstanding Talk for his talk “Type-I IFNs induce GBPs and lysosomal defense in hepatocytes to control malaria” at the American Association of Immunologists annual meeting.
Alex Garrot (Kurup Lab) received a 3rd place poster award at the Woods Hole Immunoparasitology meeting.
CTEGD members in the news
Rick Tarleton:
Researchers secure funding to advance Chagas disease research (News-Medical.net)
Investigators are studying Chagas disease with a One Health approach (DVM360)
UGA and Texas A&M Researchers tackle Chagas disease in dogs and humans (WUGA)
Countable Labs Launches Single-Molecule DNA Counting System, PCR Application (GenomeWeb)
UGA Pioneers First Test for Chagas Disease Cure (Mirage)
UGA researchers develop first test of cure for Chagas disease (Newswise)
¿Se curó la infección de Chagas? Un nuevo test podría dar la respuesta (Infobae)
Rick Tarleton discusses Chagas disease on Outbreak News Today.
Dan Colley shares about his career studying Schistosomes.
Chet Joyner discusses his research on the liver stage of malaria.
Doug Paton talks about his groundbreaking work on an incredible new way to treat malaria.
Recently published research
The Tarleton Research Group discusses the importance of persistence and dormancy in Trypanosoma cruzi infection and Chagas disease in a review published in Current Opinion in Microbiology.
Read more of the recently published research from all our labs.
Newly funded projects
Chet Joyner received an award from Abbott Laboratories for the production of Plasmodium isolates. He also received an award from the National Institutes of Health to establish P. vivax lines that grow in optimized culture conditions to develop a continuous, high yield culture system for P. vivax to support mechanistic studies that will lead to new therapies. A grant from Good Ventures Foundation will fund preclinical evaluation of safety, immunogenicity and protective efficacy against P. falciparum challenge of a nanoparticle vaccine encoding a Plasmodium MIF ortholog in Aotus nancymaae. Medcicnes for Malaria Venture has funded Joyner’s project for SERCAP testing for MMV2682.
Rick Tarleton received an award from the National Institutes of Health. The goal of this project is to complete adaptation of the rapid and inexpensive T. cruzi UltraPCR method for highsensitivity detection of T. cruzi, validate its use for confirming infection and monitoring treatment impact, and provide the justification for ultimately deploying this assay for human and veterinary diagnostic use. With his collaborators at Texas A&M University, he also received a US Department of Homeland Security grant for a Canine Chagas Disease Prevalence, Prevention, and Operational Capability Protection Study.
Vasant Muralidharan, with collaborators at the University of California – Riverside, received a grant from the National Institutes of Health for Decoding the Role of Non-Coding RNAs in Gene Regulation.
Sam Kurup received a grant from the National Institutes of Health to study the mechanisms of human immune response to Plasmodium infection in the liver.
Chris West, in collaboration with colleagues at Virginia Polytechnic Institute, received two grants from the National Institutes of Health. One to study protist oxygen sensing in human disease and the other is to study the organization and function of the Toxoplasma daughter cell scaffold.
New test protocol can detect low levels of Trypanosoma cruzi, the parasite that causes Chagas disease
Researchers at the University of Georgia’s Center for Tropical and Emerging Global Diseases have developed the first test to determine whether treatment for Chagas disease was effective.
An estimated 6 million to 8 million people worldwide are infected with Trypanosoma cruzi, the parasite that causes Chagas disease.
“Currently during drug trials, we can only determine if a drug fails,” said Rick Tarleton, Regents’ Professor in the UGA Franklin College of Arts and Sciences. “A test of cure can indicate if a drug succeeds in clearing the infection.”
Rick Tarleton of the Center for Tropical and Emerging Global Diseases
Part of the problem in determining if T. cruzi infection is cured by treatment is that the immune system is often very good at controlling the infection. Current tests are not sensitive enough to detect low levels of parasites.
“If you have a cup a tea with a little bit of tea leaf in it you may not get a tea leaf in every sip,” Tarleton said. “When there are so few parasites in the blood stream, it decreases the chances that a blood draw will contain any.
“We’ve taken two samples from the same individual at the same time—one sample tests positive, and the other tests negative. Which is right?”
Thousands die from Chagas each year
Chagas disease kills more than 10,000 people every year, mainly in Central and South America. But it is also a concern in the United States, where the Centers for Disease Control and Prevention estimates there are 280,000 people living with this disease.
And it’s not only humans that suffer from this disease. Many mammals, including wildlife and dogs, can also become infected.
The Tarleton group conducted large-scale PCR testing of samples from naturally infected macaque monkeys, dogs and humans. The team also fragmented the DNA to more evenly distribute it within the sample. Standard PCR testing doesn’t fragment DNA.
“If we go back to Rick’s tea leaf example, it’s like taking the whole tea leaf, breaking it up into tiny bits and then stirring the tea before taking a sip,” said Brooke White, lead researcher of the study. “This increases the chances of detecting DNA.”
New test accurately detects parasite infection in monkeys, dogs and humans
The naturally infected macaques were monitored over 12 months with monthly blood tests. A subset also had blood samples drawn seven times over four weeks. In addition to the exhaustive PCR testing, the researchers grew T. cruzi cultures from the blood samples, which confirmed that the new protocol accurately detects infection even when the parasite number is very low.
“Since the macaques acquired the infection in the same way as humans and dogs and their disease progression is the same, we are confident that this test will work in other species,” said Tarleton.
Collaborators at Texas A&M and in Argentina also provided naturally infected dog and human samples, respectively. The researchers saw similar results to the macaques.
A need for better drug treatment for Chagas disease
There is a need for new drug treatments for Chagas disease. But without a true test of cure, researchers only know what does not work. While the new protocol is effective, the researchers noted that it is also labor intensive and time consuming, which translates into being costly.
As part of the study, the researchers sought out technologies that could make the process faster and cheaper.
“This test of cure is a real game changer for drug treatment studies,” said White. “We are already working with other research groups in hopes of creating a quicker and cheaper method of testing parasite load in their drug treatment studies in macaques, dogs and humans.”
The researchers began collaborating with Countable Labs whose new technology allows for larger samples to be assayed faster. Reducing costs and increasing efficiency makes it much more likely for this test to be used in a clinical setting.
“Our goal now is to move this test out of the research lab and into a clinical diagnostic lab where it will be widely accessible for detecting human and dog infections and tracking treatment outcomes,” said Tarleton.
Amino acid alignment between GP60 sequences from all four C. parvum IOWA II genome assemblies analyzed.
Cryptosporidium parvum is a significant pathogen causing gastrointestinal infections in humans and animals. It is spread through ingesting contaminated food and water. Despite its global health significance, generating a C. parvum genome sequence has been challenging for many reasons including cloning and challenging subtelomeric regions. A new, gapless, hybrid, telomere-to-telomere genome assembly was created for C. parvum IOWA II, here termed CpBGF. It reveals 8 chromosomes, a genome size of 9,259,183 bp, and resolves complex subtelomeric regions. To facilitate ease of use and consistency with the literature, the chromosomes have been oriented, and genes in this annotation have been given similar gene IDs as those used in the 2004, C. parvum IOWA II reference genome sequence. The new annotation utilized considerable RNA expression evidence including single-molecule Iso-Seq data; thus, untranslated regions, long noncoding RNAs, and antisense RNAs are annotated. The CpBGF genome assembly serves as a valuable resource for understanding the biology, pathogenesis, and transmission of C. parvum, and it facilitates the development of diagnostics, drugs, and vaccines against cryptosporidiosis.
T. cruzi-specific CD8+ T cells cross-react with multiple flagellar peptides.
CD8+ T cells are key effectors in immune control of Trypanosoma cruzi infection. Within C57BL/6 mice, the T. cruzi-specific CD8+ T cell response is largely comprised of T cells recognizing trans-sialidase (TS)- and mucin-encoded epitopes. Despite their immunodominance, these epitope-specific CD8+ T cells are entirely dispensable for immune control. In a screen for epitopes inducing “protective” CD8+ T cells, we uncovered a high level of cross-reactivity within the TSKb20-specific CD8+ T cell response. This cross-reactivity was driven by the TSKb20 epitope itself and not the infection. TCR sequencing defined key characteristics of the TSKb20 repertoire including biased TRBV12-1/12-2 and TRBJ2-1/2-7 gene usage and a highly dominant CDR3β motif. The dispensability of the TSKb20 response in the control of T. cruzi infection along with the broad reactivity of this T cell population prompted us to assess the relative effector capacity of TSKb20 T cells at the site of reinfection. Similar to other activated CD8+ T cells at the site, TSKb20-specific CD8+ T cells expressed transcriptional patterns associated with effector function, suggesting that TSKb20 T cells are capable and likely participants in parasite control. These results indicate that broad TCR reactivity does not compromise the ability of TSKb20-specific T cells to develop into phenotypically functional effectors. Additionally, the failure to identify individual parasite epitopes capable of driving a protective CD8+ T cell response challenges the paradigm that individual T. cruzi epitopes, including highly immunodominant ones, are critical to or exploitable for the potent recognition of T. cruzi-infected host cells and infection control.
A target specimen profile (TSP) corresponds to the required characteristics of the specimen panels needed to demonstrate that a diagnostic kit meets the target product profile (TPP). TSPs can guide biobanks in the prospective collection of sample panels to support the development and validation of diagnostics.
Human infections by Trypanosoma cruzi propagate via its blood-feeding triatomine vector. Investigating parasite-vector interactions depends upon robust techniques to rear insects and analyze infections. Here, we present a protocol for laboratory rearing and infection tracking of Rhodnius prolixus. We describe steps for housing, feeding, and sorting strategies using 3D-printable designs. We also detail procedures for gut dissection, fecal collection, and parasite re-isolation. This protocol describes techniques that support efforts to understand and mitigate vector-mediated Chagas disease transmission.
