Artemisinins have revolutionized the treatment of
Drug resistance is an obstacle to global malaria control, as evidenced by the recent emergence and rapid spread of delayed artemisinin (ART) clearance by mutant forms of the
- NSF-PAR ID:
- 10079384
- Publisher / Repository:
- Proceedings of the National Academy of Sciences
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 115
- Issue:
- 50
- ISSN:
- 0027-8424
- Page Range / eLocation ID:
- p. 12799-12804
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Plasmodium falciparum malaria; however, resistance threatens to undermine global control efforts. To broadly explore artemisinin susceptibility in apicomplexan parasites, we employ genome-scale CRISPR screens recently developed forToxoplasma gondii to discover sensitizing and desensitizing mutations. Using a sublethal concentration of dihydroartemisinin (DHA), we uncover the putative transporter Tmem14c whose disruption increases DHA susceptibility. Screens performed under high doses of DHA provide evidence that mitochondrial metabolism can modulate resistance. We show that disrupting a top candidate from the screens, the mitochondrial protease DegP2, lowers porphyrin levels and decreases DHA susceptibility, without significantly altering parasite fitness in culture. Deleting the homologous gene inP. falciparum, PfDegP , similarly lowers heme levels and DHA susceptibility. These results expose the vulnerability of heme metabolism to genetic perturbations that can lead to increased survival in the presence of DHA. -
Listeria phage LP-018 is the only phage from a diverse collection of 120 phages able to form plaques on a phage-resistant Listeria monocytogenes strain lacking rhamnose in its cell wall teichoic acids. The aim of this study was to characterize phage LP-018 and to identify what types of mutations can confer resistance to LP-018. Whole genome sequencing and transmission electron microscopy revealed LP-018 to be a member of the Homburgvirus genus. One-step-growth curve analysis of LP-018 revealed an eclipse period of ~60–90 min and a burst size of ~2 PFU per infected cell. Despite slow growth and small burst size, LP-018 can inhibit the growth of Listeria monocytogenes at a high multiplicity of infection. Ten distinct LP-018-resistant mutants were isolated from infected Listeria monocytogenes 10403S and characterized by whole genome sequencing. In each mutant, a single mutation was identified in either the LMRG_00278 or LMRG_01613 encoding genes. Interesting, LP-018 was able to bind to a representative phage-resistant mutant with a mutation in each gene, suggesting these mutations confer resistance through a mechanism independent of adsorption inhibition. Despite forming plaques on the rhamnose deficient 10403S mutant, LP-018 showed reduced binding efficiency, and we did not observe inhibition of the strain under the conditions tested. Two mutants of LP-018 were also isolated and characterized, one with a single SNP in a gene encoding a BppU domain protein that likely alters its host range. LP-018 is shown to be a unique Listeria phage that, with additional evaluation, may be useful in biocontrol applications that aim to reduce the emergence of phage resistance.more » « less
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Abstract Lactic acid bacteria produce a variety of antimicrobial peptides known as bacteriocins. Most bacteriocins are understood to kill sensitive bacteria through receptor‐mediated disruptions. Here, we report on the identification of the
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Abstract Background Co‐occurrence of two genetic diseases is challenging for accurate diagnosis and genetic counseling. The recent availability of whole exome sequencing (
WES ) has dramatically improved the molecular diagnosis of rare genetic diseases in particular in consanguineous populations.Methods We report here on a consanguineous family from Southern Tunisia including three members affected with congenital ichthyosis. The index case had a hearing loss (
HL ) and ichthyosis and was primarily suspected as suffering from keratitis‐ichthyosis‐deafness (KID ) syndrome.WES was performed for the index case, and all members of the nuclear family were sequenced (Sanger method).Results The
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Abstract Mutations in the
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