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Namayanja M, Dai Y, Nerima B, Matovu E, Lun ZR, Lubega GW, Zhengjun C. Trypanosoma brucei brucei traverses different biological barriers differently and may modify the host plasma membrane in the process. Exp Parasitol 2016; 174:31-41. [PMID: 28011167 DOI: 10.1016/j.exppara.2016.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 12/07/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
Trypanosoma brucei are extracellular hemoflagellate protozoan parasites and one of the causative agents of a devastating zoonotic disease called African Trypanosomiasis. In humans, the disease is caused by Trypanosoma brucei rhodensiense and Trypanosoma brucei gambiense, which cross the blood brain barrier (BBB) causing neurological disorders which culminate in death if untreated. In some domestic animals and laboratory rodents, Trypanosoma brucei brucei causes a disease similar to that in humans. The mechanism by which Trypanosoma brucei brucei invade biological barriers including the BBB has not been fully elucidated. To further address this issue, Mardin Dardy Canine Kidney II (MDCKII) and Human dermal microvascular endothelial cell (HDMEC) monolayers were grown to confluence on transwell inserts to constitute in vitro biological barriers. MDCKII cells were chosen for their ability to form tight junctions similar to those formed by the BBB endothelial cells. Labeled trypanosomes were placed in the upper chamber of transwell inserts layered with confluent MDCKII/HDMEC monolayers and their ability to cross the monolayer over time evaluated. Our results show that only 0.5-1.25% of Trypanosoma brucei brucei were able to migrate across the monolayers after 3 h. By employing immune-staining and confocal microscopic analysis we observed that trypanosomes were located at the tight junctions and inside the cell in the MDCK II monolayers indicating that they crossed the monolayer using both the paracellular and transcellular routes. Our observations also showed that there seemed to be no obvious degradation of junction proteins Zonula Ocludens-1, Occludin and Ecadherin. In the HDMEC cell monolayer, our scanning electron microscopy data showed that Trypanosoma brucei brucei is able to modulate the plasma membrane to form invaginations similar to cuplike structures formed by Tlymphocytes. However these structures seemed to be independent of vascular adhesion molecules suggesting that they could be more like the membrane ruffles formed by certain intracellular bacteria during invasion. Taken together, our data reveal a mechanism by which Trypanosoma brucei brucei is able to cross different biological barriers including the BBB without causing any obvious damage.
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Affiliation(s)
- Monica Namayanja
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, 200031, Shanghai, China; Molecular Biology Laboratory, School of Biotechnical, Biosecurity and Laboratory Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
| | - Yan Dai
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, 200031, Shanghai, China
| | - Barbara Nerima
- Molecular Biology Laboratory, School of Biotechnical, Biosecurity and Laboratory Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Enock Matovu
- Molecular Biology Laboratory, School of Biotechnical, Biosecurity and Laboratory Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Zhao-Rong Lun
- Centre for Parasitic Organisms, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510276, China
| | - George W Lubega
- Molecular Biology Laboratory, School of Biotechnical, Biosecurity and Laboratory Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Chen Zhengjun
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, 200031, Shanghai, China
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Ahmed HA, MacLeod ET, Welburn SC, Picozzi K. Development of real time PCR to study experimental mixed infections of T. congolense Savannah and T. b. brucei in Glossina morsitans morsitans. PLoS One 2015; 10:e0117147. [PMID: 25738803 PMCID: PMC4349444 DOI: 10.1371/journal.pone.0117147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 12/18/2014] [Indexed: 11/18/2022] Open
Abstract
Tsetse flies are able to acquire mixed infections naturally or experimentally either simultaneously or sequentially. Traditionally, natural infection rates in tsetse flies are estimated by microscopic examination of different parts of the fly after dissection, together with the isolation of the parasite in vivo. However, until the advent of molecular techniques it was difficult to speciate trypanosomes infections and to quantify trypanosome numbers within tsetse flies. Although more expensive, qPCR allows the quantification of DNA and is less time consuming due to real time visualization and validation of the results. The current study evaluated the application of qPCR to quantify the infection load of tsetse flies with T. b. brucei and T. congolense savannah and to study the possibility of competition between the two species. The results revealed that the two qPCR reactions are of acceptable efficiency (99.1% and 95.6%, respectively), sensitivity and specificity and can be used for quantification of infection load with trypanosomes in experimentally infected Glossina morsitans morsitans. The mixed infection of laboratory Glossina species and quantification of the infection suggests the possibility that a form of competition exists between the isolates of T. b. brucei and T. congolense savannah that we used when they co-exist in the fly midgut.
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Affiliation(s)
- Heba A. Ahmed
- Division of Pathway Medicine, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
- Faculty of Veterinary Medicine, Zagazig University, Zagazig, Ash Sharqiyah, Egypt
| | - Ewan T. MacLeod
- Division of Pathway Medicine, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Susan C. Welburn
- Division of Pathway Medicine, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Kim Picozzi
- Division of Pathway Medicine, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Van den Bossche P, Ky-Zerbo A, Brandt J, Marcotty T, Geerts S, De Deken R. Transmissibility of Trypanosoma brucei during its development in cattle. Trop Med Int Health 2005; 10:833-9. [PMID: 16135189 DOI: 10.1111/j.1365-3156.2005.01467.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent outbreaks of Trypanosoma brucei rhodesiense sleeping sickness in Soroti District of eastern Uganda have demonstrated the important role cattle can play as reservoirs of this parasite. To clarify the epidemiological importance of the cattle reservoir, experiments were conducted to determine the ease with which T. brucei is transmitted during the course of its development in Friesian cattle. The development of T. brucei in cattle is characterized by an acute phase with high levels of parasitaemia and a decline in PCV. The acute phase is followed by a chronic phase during which the PCV remains low but stable and the parasitaemia is low. Parasites are often difficult to detect using parasitological diagnostic tools during this chronic phase. Challenge of chronically infected cattle with T. congolense results in a sudden increase in the T. brucei parasitaemia. Despite significant differences in parasitaemia, the proportion of tsetse flies that developed metacyclic infections after a first bloodmeal on the infected cattle did not differ significantly between the acute and chronic phases or the phase of mixed T. b. brucei/T. congolense infection. This suggests that, throughout the observation period, the parasitaemia was above the threshold above which infection rates of tsetse are independent of the parasitaemia. The repercussions of the research findings for the understanding of the epidemiology, spread and the control of T. b. rhodesiense sleeping sickness are discussed.
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Affiliation(s)
- P Van den Bossche
- Animal Health Department, Institute of Tropical Medicine, Antwerpen, Belgium.
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Claes F, Büscher P, Touratier L, Goddeeris BM. Trypanosoma equiperdum: master of disguise or historical mistake? Trends Parasitol 2005; 21:316-21. [PMID: 15923142 DOI: 10.1016/j.pt.2005.05.010] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 03/10/2005] [Accepted: 05/10/2005] [Indexed: 11/24/2022]
Abstract
After 100 years of research, only a small number of laboratory strains of Trypanosoma equiperdum exists, and the history of most of the strains is unknown. No definitive diagnosis of dourine can be made at the serological or molecular level. Only clinical signs are pathognomonic and international screening relies on an outdated cross-reactive serological test (the complement-fixation test) from 1915, resulting in serious consequences at the practical level. Despite many characterization attempts, no clear picture has emerged of the position of T. equiperdum within the Trypanozoon group. In this article, we highlight the controversies that exist regarding T. equiperdum, and the overlap that occurs with Trypanosoma evansi and Trypanosoma brucei brucei. By revisiting the published data, from the early decades of discovery to the recent serological- and molecular-characterization studies, a new hypothesis arises in which T. equiperdum no longer exists as a separate species and in which current strains can be divided into T. evansi (the historical mistake) and Trypanosoma brucei equiperdum (the master of disguise). Hence, dourine is a disease caused by specific host immune responses to a T. b. equiperdum or T. evansi infection.
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Affiliation(s)
- Filip Claes
- Katholieke Universiteit Leuven Leuven, Faculty of Applied Bioscience and Engineering, Department of Animal Sciences, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
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