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Murphy SC, Ishizuka AS, Billman ZP, Olsen TM, Seilie AM, Chang M, Smith N, Chuenchob V, Chakravarty S, Sim BKL, Kappe SHI, Hoffman SL, Seder RA. Plasmodium 18S rRNA of intravenously administered sporozoites does not persist in peripheral blood. Malar J 2018; 17:275. [PMID: 30053881 PMCID: PMC6062992 DOI: 10.1186/s12936-018-2422-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/19/2018] [Indexed: 01/14/2023] Open
Abstract
Background Plasmodium 18S rRNA is a biomarker used to monitor blood-stage infections in malaria clinical trials. Plasmodium sporozoites also express this biomarker, and there is conflicting evidence about how long sporozoite-derived 18S rRNA persists in peripheral blood. If present in blood for an extended timeframe, sporozoite-derived 18S rRNA could complicate use as a blood-stage biomarker. Methods Blood samples from Plasmodium yoelii infected mice were tested for Plasmodium 18S rRNA and their coding genes (rDNA) using sensitive quantitative reverse transcription PCR and quantitative PCR assays, respectively. Blood and tissues from Plasmodium falciparum sporozoite (PfSPZ)-infected rhesus macaques were similarly tested. Results In mice, when P. yoelii sporozoite inoculation and blood collection were performed at the same site (tail vein), low level rDNA positivity persisted for 2 days post-infection. Compared to intact parasites with high rRNA-to-rDNA ratios, this low level positivity was accompanied by no increase in rRNA-to-rDNA, indicating detection of residual, non-viable parasite rDNA. When P. yoelii sporozoites were administered via the retro-orbital vein and blood sampled by cardiac puncture, neither P. yoelii 18S rRNA nor rDNA were detected 24 h post-infection. Similarly, there was no P. falciparum 18S rRNA detected in blood of rhesus macaques 3 days after intravenous injection with extremely high doses of PfSPZ. Plasmodium 18S rRNA in the rhesus livers increased by approximately 101-fold from 3 to 6 days post infection, indicating liver-stage proliferation. Conclusions Beyond the first few hours after injection, sporozoite-derived Plasmodium 18S rRNA was not detected in peripheral blood. Diagnostics based on 18S rRNA are unlikely to be confounded by sporozoite inocula in human clinical trials.
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Affiliation(s)
- Sean C Murphy
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA. .,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, 750 Republican St., Seattle, WA, 98109, USA.
| | - Andrew S Ishizuka
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 40, Room 3512, 40 Convent Drive, Bethesda, MD, 20814, USA
| | - Zachary P Billman
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Tayla M Olsen
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Annette M Seilie
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Ming Chang
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Nahum Smith
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Vorada Chuenchob
- Center for Infectious Disease Research, 307 Westlake Ave N #500, Seattle, WA, 98109, USA
| | - Sumana Chakravarty
- Sanaria, Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD, 20850, USA
| | - B Kim Lee Sim
- Sanaria, Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD, 20850, USA
| | - Stefan H I Kappe
- Center for Infectious Disease Research, 307 Westlake Ave N #500, Seattle, WA, 98109, USA
| | - Stephen L Hoffman
- Sanaria, Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD, 20850, USA
| | - Robert A Seder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 40, Room 3512, 40 Convent Drive, Bethesda, MD, 20814, USA
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Martinson SA, Greenwood SJ, Wadowska D, Martin K. Histopathological, ultrastructural and molecular phylogenetic analysis of a novel microsporidium in a loggerhead sea turtle Caretta caretta. Dis Aquat Organ 2018; 129:31-39. [PMID: 29916390 DOI: 10.3354/dao03234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Microsporidial spores were identified in the musculature of a loggerhead sea turtle Caretta caretta found dead on the shore in New Brunswick, Canada. Gastroenteritis was diagnosed on gross postmortem examination, with no gross abnormalities detected in the skeletal muscle. Histologically, the microsporidial spores were associated with inflammation and muscular necrosis and measured 1.1-1.7 × 2.2-3.4 µm. Spores were typically identified within sporophorous vesicles and, less often, in sporophorocysts and were weakly Gram positive, had punctate PAS staining, and were occasionally strongly acid-fast. Ultrastructural characteristics included 7-10 polar filament coils and other standard features of microsporidial spores. PCR for the microsporidial small subunit rRNA gene sequence was performed on DNA extracted from the muscle and small intestine, and the resulting amplicon was sequenced and queried against published microsporidial genomes. DNA sequences shared 98.2-99.8% sequence identity to Clade III of the Marinosporidia. This is the first report of a microsporidial infection contributing to the mortality of a sea turtle.
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Affiliation(s)
- S A Martinson
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada
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Ahmad N, Johri S, Sultan P, Abdin MZ, Qazi GN. Phylogenetic characterization of archaea in saltpan sediments. Indian J Microbiol 2011; 51:132-7. [PMID: 22654153 DOI: 10.1007/s12088-011-0125-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 07/06/2009] [Indexed: 10/18/2022] Open
Abstract
A study was undertaken to investigate the presence of archaeal diversity in saltpan sediments of Goa, India by 16S rDNA-dependent molecular phylogeny. Small subunit rRNA (16S rDNA) from saltpan sediment metagenome were amplified by polymerase chain reaction (PCR) using primers specific to the domain archaea. 10 unique phylotypes were obtained by PCR based RFLP of 16S rRNA genes using endonuclease Msp 1, which was most suitable to score the genetic diversity. These phylotypes spanned a wide range within the domain archaea including both crenarchaeota and euryarcheaota. None of the retrieved crenarchaeota sequences could be grouped with previously cultured crenarchaeota however; two sequences were related with haloarchaea. Most of the sequences determined were closely related to the sequences that had been previously obtained from metagenome of a variety of marine environments. The phylogenetic study of a site investigated for the first time revealed the presence of low archaeal population but showed yet unclassified species, may specially adapted to the salt pan sediment of Goa.
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