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Morgado P, Manna D, Singh U. Recent advances in Entamoeba biology: RNA interference, drug discovery, and gut microbiome. F1000Res 2016; 5:2578. [PMID: 27853522 PMCID: PMC5089142 DOI: 10.12688/f1000research.9241.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/17/2016] [Indexed: 01/04/2023] Open
Abstract
In recent years, substantial progress has been made in understanding the molecular and cell biology of the human parasite
Entamoeba histolytica, an important pathogen with significant global impact. This review outlines some recent advances in the
Entamoeba field in the last five years, focusing on areas that have not recently been discussed in detail: (i) molecular mechanisms regulating parasite gene expression, (ii) new efforts at drug discovery using high-throughput drug screens, and (iii) the effect of gut microbiota on amoebiasis.
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Affiliation(s)
- Pedro Morgado
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Dipak Manna
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Upinder Singh
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, USA.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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Yin F, Sun P, Wang J, Gao Q. Transcriptome analysis of dormant tomonts of the marine fish ectoparasitic ciliate Cryptocaryon irritans under low temperature. Parasit Vectors 2016; 9:280. [PMID: 27177617 PMCID: PMC4867990 DOI: 10.1186/s13071-016-1550-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 04/27/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Cryptocaryon irritans, a species of obligatory ciliate ectoparasite, can infect various species of marine teleost fish. Cryptocaryon irritans that fall to the seabed or aquarium bottom in winter can form "dormant tomonts" and wake up when the temperature rises the next year. Abundant studies and analyses on the dormant tomonts were carried out at the transcriptome level, in order to investigate the molecular mechanism of C. irritans tomonts entering the dormant state under low-temperature conditions. METHODS The paired-end sequencing strategy was used to better assemble the entire transcriptome de novo. All clean sequencing reads from each of the three libraries (Group A: untreated blank control; Group B: treated for 24 h at 12 °C; and Group C: developed for 24 h at 25 °C) were respectively mapped back to the transcriptome assembly using the bioinformatics software. RESULTS In this study, 25,695,034, 21,944,467, and 28,722,875 paired-end clean reads were obtained respectively from the three cDNA libraries of the C. irritans tomont by Illumina paired-end sequencing technology. A total of 25,925 unique transcript fragments (unigenes) were assembled, with an average length of 839 bp. Differentially expressed genes (DEGs) were scrutinized; in Group B/A pairwise comparison, 343 genes presented differential expression, including 265 up-regulated genes and 78 down-regulated genes in Group B; in Group C/A pairwise comparison, there were 567 DEGs, including 548 up-regulated genes and 19 down-regulated genes in Group C; and in Group B/C pairwise comparison, 185 genes showed differential expression, including 145 up-regulated genes and 40 down-regulated genes in Group B. CONCLUSIONS This is the first transcriptomic analytical study of the C. irritans tomonts under low temperature. It can be concluded that most of the genes required for its cell survival under low temperature, or for cell entry into a deeper dormancy state were discovered, and that they might be considered as candidate genes to develop the diagnostic and control measures for cryptocaryoniasis.
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Affiliation(s)
- Fei Yin
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Room 316, Building 6, 300 Jungong Road, Shanghai, 200090, PR China.
| | - Peng Sun
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Room 316, Building 6, 300 Jungong Road, Shanghai, 200090, PR China
| | - Jiteng Wang
- Fisheries College of Zhejiang Ocean University, Zhoushan, Zhejiang, 316022, PR China
| | - Quanxin Gao
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Room 316, Building 6, 300 Jungong Road, Shanghai, 200090, PR China
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Hermosilla C, Silva LMR, Kleinertz S, Prieto R, Silva MA, Taubert A. Endoparasite survey of free-swimming baleen whales (Balaenoptera musculus, B. physalus, B. borealis) and sperm whales (Physeter macrocephalus) using non/minimally invasive methods. Parasitol Res 2015; 115:889-96. [PMID: 26593736 DOI: 10.1007/s00436-015-4835-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/12/2015] [Indexed: 02/04/2023]
Abstract
A number of parasitic diseases have gained importance as neozoan opportunistic infections in the marine environment. Here, we report on the gastrointestinal endoparasite fauna of three baleen whale species and one toothed whale: blue (Balaenoptera musculus), fin (Balaenoptera physalus), and sei whales (Balaenoptera borealis) and sperm whales (Physeter macrocephalus) from the Azores Islands, Portugal. In total, 17 individual whale fecal samples [n = 10 (B. physalus); n = 4 (P. macrocephalus); n = 2 (B. musculus); n = 1 (B. borealis)] were collected from free-swimming animals as part of ongoing studies on behavioral ecology. Furthermore, skin biopsies were collected from sperm whales (n = 5) using minimally invasive biopsy darting and tested for the presence of Toxoplasma gondii, Neospora caninum, and Besnoitia besnoiti DNA via PCR. Overall, more than ten taxa were detected in whale fecal samples. Within protozoan parasites, Entamoeba spp. occurred most frequently (64.7%), followed by Giardia spp. (17.6%) and Balantidium spp. (5.9%). The most prevalent metazoan parasites were Ascaridida indet. spp. (41.2%), followed by trematodes (17.7%), acanthocephalan spp., strongyles (11.8%), Diphyllobotrium spp. (5.9%), and spirurids (5.9%). Helminths were mainly found in sperm whales, while enteric protozoan parasites were exclusively detected in baleen whales, which might be related to dietary differences. No T. gondii, N. caninum, or B. besnoiti DNA was detected in any skin sample. This is the first record on Giardia and Balantidium infections in large baleen whales.
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Affiliation(s)
- Carlos Hermosilla
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392, Giessen, Germany.
| | - Liliana M R Silva
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392, Giessen, Germany
| | - Sonja Kleinertz
- Aquaculture and Sea-Ranching, Faculty of Agricultural and Environmental Sciences, University of Rostock, 18059, Rostock, Germany
| | - Rui Prieto
- MARE-Marine and Environmental Sciences Centre and IMAR-Institute of Marine Research, University of the Azores, 9901-862, Horta, Portugal
| | - Monica A Silva
- MARE-Marine and Environmental Sciences Centre and IMAR-Institute of Marine Research, University of the Azores, 9901-862, Horta, Portugal.,Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Anja Taubert
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392, Giessen, Germany
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Zhang H, Ehrenkaufer GM, Manna D, Hall N, Singh U. High Throughput Sequencing of Entamoeba 27nt Small RNA Population Reveals Role in Permanent Gene Silencing But No Effect on Regulating Gene Expression Changes during Stage Conversion, Oxidative, or Heat Shock Stress. PLoS One 2015; 10:e0134481. [PMID: 26248204 PMCID: PMC4527709 DOI: 10.1371/journal.pone.0134481] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/10/2015] [Indexed: 01/09/2023] Open
Abstract
The human parasite Entamoeba histolytica has an active RNA interference (RNAi) pathway with an extensive repertoire of 27nt small RNAs that silence genes. However the role of this pathway in regulating amebic biology remains unknown. In this study, we address whether silencing via 27nt small RNAs may be a mechanism for controlling gene expression changes during conversion between the trophozoite and cyst stages of the parasite. We sequenced small RNA libraries generated from trophozoites, early cysts, mature cysts, and excysting cells and mapped them to the E. invadens genome. Our results show that, as in E. histolytica, small RNAs in E. invadens are largely ~27nt in length, have an unusual 5'-polyphosphate structure and mediate gene silencing. However, when comparing the libraries from each developmental time-point we found few changes in the composition of the small RNA populations. Furthermore, genes targeted by small RNAs were permanently silenced with no changes in transcript abundance during development. Thus, the E. invadens 27nt small RNA population does not mediate gene expression changes during development. In order to assess the generalizability of our observations, we examined whether small RNAs may be regulating gene expression changes during stress response in E. histolytica. Comparison of the 27nt small RNA populations from E. histolytica trophozoites from basal conditions, or after heat shock or exposure to oxidative stress showed few differences. Similar to data in E. invadens development, genes targeted by small RNAs were consistently silenced and did not change expression under tested stress conditions. Thus, the biological roles of the 27nt small RNA population in Entamoeba remain elusive. However, as the first characterization of the RNAi pathway in E. invadens these data serve as a useful resource for the study of Entamoeba development and open the door to the development of RNAi-based gene silencing tools in E. invadens.
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Affiliation(s)
- Hanbang Zhang
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Gretchen M. Ehrenkaufer
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Dipak Manna
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Neil Hall
- Center for Genomic Research, Institute of Integrative Biology, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Upinder Singh
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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Ahamad J, Ojha S, Srivastava A, Bhattacharya A, Bhattacharya S. Post-transcriptional regulation of ribosomal protein genes during serum starvation in Entamoeba histolytica. Mol Biochem Parasitol 2015; 201:146-52. [PMID: 26247142 DOI: 10.1016/j.molbiopara.2015.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/29/2015] [Accepted: 07/31/2015] [Indexed: 12/19/2022]
Abstract
Ribosome synthesis involves all three RNA polymerases which are co-ordinately regulated to produce equimolar amounts of rRNAs and ribosomal proteins (RPs). Unlike model organisms where transcription of rRNA and RP genes slows down during stress, in E. histolytica rDNA transcription continues but pre-rRNA processing slows down and unprocessed pre-rRNA accumulates during serum starvation. To investigate the regulation of RP genes under stress we measured transcription of six selected RP genes from the small- and large-ribosomal subunits (RPS6, RPS3, RPS19, RPL5, RPL26, RPL30) representing the early-, mid-, and late-stages of ribosomal assembly. Transcripts of these genes persisted in growth-stressed cells. Expression of luciferase reporter under the control of two RP genes (RPS19 and RPL30) was studied during serum starvation and upon serum replenishment. Although luciferase transcript levels remained unchanged during starvation, luciferase activity steadily declined to 7.8% and 15% of control cells, respectively. After serum replenishment the activity increased to normal levels, suggesting post-transcriptional regulation of these genes. Mutations in the sequence -2 to -9 upstream of AUG in the RPL30 gene resulted in the phenotype expected of post-transcriptional regulation. Transcription of luciferase reporter was unaffected in this mutant, and luciferase activity did not decline during serum starvation, showing that this sequence is required to repress translation of RPL30 mRNA, and mutations in this region relieve repression. Our data show that during serum starvation E. histolytica blocks ribosome biogenesis post-transcriptionally by inhibiting pre-rRNA processing on the one hand, and the translation of RP mRNAs on the other.
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Affiliation(s)
- Jamaluddin Ahamad
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Sandeep Ojha
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Ankita Srivastava
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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