scholarly journals Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly’s midgut environment

2021 ◽  
Vol 17 (6) ◽  
pp. e1009475
Author(s):  
Liu Yang ◽  
Brian L. Weiss ◽  
Adeline E. Williams ◽  
Emre Aksoy ◽  
Alessandra de Silva Orfano ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Expression System ◽  
Transcript Abundance ◽  
P Value ◽  
Secretory Proteins ◽  
Tsetse Flies ◽  
Infection Prevalence ◽  
Trypanosome Infection ◽  
African Trypanosomes ◽  
Infected People

Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse’s ability to transmit trypanosomes by strengthening the fly’s natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse’s PM in order to establish an infection in the fly, and PM structural integrity negatively correlates with trypanosome infection outcomes. Bloodstream form trypanosomes shed variant surface glycoproteins (VSG) into tsetse’s gut lumen early during the infection establishment, and free VSG molecules are internalized by the fly’s PM-producing cardia. This process results in a reduction in the expression of a tsetse microRNA (miR275) and a sequential molecular cascade that compromises PM integrity. miRNAs are small non-coding RNAs that are critical in regulating many physiological processes. In the present study, we investigated the role(s) of tsetse miR275 by developing a paratransgenic expression system that employs tsetse’s facultative bacterial endosymbiont, Sodalis glossinidius, to express tandem antagomir-275 repeats (or miR275 sponges). This system induces a constitutive, 40% reduction in miR275 transcript abundance in the fly’s midgut and results in obstructed blood digestion (gut weights increased by 52%), a significant increase (p-value < 0.0001) in fly survival following infection with an entomopathogenic bacteria, and a 78% increase in trypanosome infection prevalence. RNA sequencing of cardia and midgut tissues from paratransgenic tsetse confirmed that miR275 regulates processes related to the expression of PM-associated proteins and digestive enzymes as well as genes that encode abundant secretory proteins. Our study demonstrates that paratransgenesis can be employed to study microRNA regulated pathways in arthropods that house symbiotic bacteria.

scholarly journals Paratransgenic manipulation of tsetse miR275 alters the physiological homeostasis of the fly’s midgut environment

2021 ◽  
Author(s):  
Liu Yang ◽  
Brian Weiss ◽  
Adeline Elizabeth Williams ◽  
Emre Aksoy ◽  
Alessandra de Silva Orfano ◽  
...  
Keyword(s):  
Expression System ◽  
Transcript Abundance ◽  
Secretory Proteins ◽  
Tsetse Flies ◽  
African Trypanosomes ◽  
Infected People ◽  
Blood Digestion ◽  
Sodalis Glossinidius ◽  
Associated Proteins ◽  
Chemotherapeutic Treatment

Tsetse flies are vectors of parasitic African trypanosomes ( Trypanosoma  spp.). Current disease control methods include fly-repelling pesticides, trapping flies, and chemotherapeutic treatment of infected people. Inhibiting tsetse’s ability to transmit trypanosomes by strengthening the fly’s natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines tsetse’s midgut. It protects the epithelial cells from the gut lumen content such as food and invading trypanosomes, which have to overcome this physical barrier to establish an infection. Bloodstream form trypanosomes shed variant surface glycoproteins (VSG) into tsetse’s gut lumen early during the infection establishment. The VSG molecules are internalized by the fly’s PM-producing cardia, which results in a reduction in tsetse  miR275  expression and a sequential molecular cascade that compromises the PM integrity. In the present study, we investigated the role(s) of  miR275  in tsetse’s midgut physiology and trypanosome infection processes by developing a paratransgenic expression system. We used tsetse’s facultative bacterial endosymbiont  Sodalis   glossinidius  to express tandem antagomir -275  repeats (or  miR275  sponge) that constitutively reduce  miR275  transcript abundance. This paratransgenic system successfully knocked down  miR275  levels in the fly’s midgut, which consequently obstructed blood digestion and modulated infection outcomes with an entomopathogenic bacteria and with trypanosomes. RNA sequencing of cardia and midgut tissues from the paratransgenic tsetse confirmed that  miR275  regulates processes related to the expression of PM-associated proteins and digestive enzymes as well as genes that encode abundant secretory proteins. Our study demonstrates that paratransgenesis can be employed to study microRNA- regulated pathways in arthropods housing symbiotic bacteria.

scholarly journals Implications of Microfauna-Host Interactions for Trypanosome Transmission Dynamics in Glossina fuscipes fuscipes in Uganda

2012 ◽  
Vol 78 (13) ◽  
pp. 4627-4637 ◽  
Author(s):  
Uzma Alam ◽  
Chaz Hyseni ◽  
Rebecca E. Symula ◽  
Corey Brelsfoard ◽  
Yineng Wu ◽  
...  
Keyword(s):  
Univariate Analysis ◽  
Spatial Diversity ◽  
The Other ◽  
Tsetse Flies ◽  
Infection Prevalence ◽  
Host Genotype ◽  
Glossina Fuscipes Fuscipes ◽  
Content Type ◽  
African Trypanosomes ◽  
Host Genetic

ABSTRACTTsetse flies (Diptera: Glossinidae) are vectors for African trypanosomes (Euglenozoa: kinetoplastida), protozoan parasites that cause African trypanosomiasis in humans (HAT) and nagana in livestock. In addition to trypanosomes, two symbiotic bacteria (Wigglesworthia glossinidiaandSodalis glossinidius) and two parasitic microbes,Wolbachiaand a salivary gland hypertrophy virus (SGHV), have been described in tsetse. Here we determined the prevalence of and coinfection dynamics betweenWolbachia, trypanosomes, and SGHV inGlossina fuscipes fuscipesin Uganda over a large geographical scale spanning the range of host genetic and spatial diversity. Using a multivariate analysis approach, we uncovered complex coinfection dynamics between the pathogens and statistically significant associations between host genetic groups and pathogen prevalence. It is important to note that these coinfection dynamics and associations with the host were not apparent by univariate analysis. These associations between host genotype and pathogen are particularly evident forWolbachiaand SGHV where host groups are inversely correlated forWolbachiaand SGHV prevalence. On the other hand, trypanosome infection prevalence is more complex and covaries with the presence of the other two pathogens, highlighting the importance of examining multiple pathogens simultaneously before making generalizations about infection and spatial patterns. It is imperative to note that these novel findings would have been missed if we had employed the standard univariate analysis used in previous studies. Our results are discussed in the context of disease epidemiology and vector control.

scholarly journals Tsetse blood-meal sources, endosymbionts, and trypanosome infections provide insight into African trypanosomiasis transmission in the Maasai Mara National Reserve, a wildlife-human-livestock interface

2020 ◽  
Author(s):  
Edward Edmond Makhulu ◽  
Jandouwe Villinger ◽  
Vincent Owino Adunga ◽  
Maamun M. Jeneby ◽  
Edwin Murungi Kimathi ◽  
...  
Keyword(s):  
Blood Meal ◽  
Vector Competence ◽  
Glossina Pallidipes ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
African Buffalo ◽  
African Trypanosomiasis ◽  
Trypanosome Infection ◽  
African Trypanosomes ◽  
Blood Meals

AbstractBackgroundAfrican trypanosomiasis (AT) is a neglected disease of both humans and animals caused by Trypanosoma parasites, which are transmitted by obligate hematophagous tsetse flies (Glossina spp.). Understanding of AT transmission is hampered by limited knowledge on interactions of tsetse flies with their vertebrate hosts and the influence of endosymbionts on vector competence, especially in wildlife-human-livestock interfaces. We identified the tsetse species, their blood-meal sources, and the correlation between endosymbiont and trypanosome infection status in the trypanosome-endemic Maasai Mara National Reserve (MMNR) of Kenya.Methodology/Principal FindingsAmong 1167 tsetse flies (1136 Glossina pallidipes, 31 Glossina swynnertoni) collected from 10 sampling sites, 28 (2.4%) were positive by PCR for trypanosomes, majority (17/28) being Trypanosoma vivax. Blood-meal analyses based on high-resolution melting analysis of mitochondrial cytochrome c oxidase 1 and cytochrome b gene PCR products (n = 345) identified humans as the most common vertebrate host (37%), followed by hippopotamus (29.1%), African buffalo (26.3%), elephant (3.39%), and giraffe (0.84%). Trypanosome-infected flies had fed on hippopotamus and buffalo. Additionally, PCR analysis revealed that tsetse flies were more likely to be infected with trypanosomes if they were infected with the Sodalis glossinidius endosymbiont (P = 0.0022 Fisher’s exact test).Conclusions/SignificanceDiverse species of wildlife hosts may contribute to the maintenance of tsetse populations and/or persistent circulation of African trypanosomes in the MMNR. Although the African buffalo is known to be a key reservoir of AT, the higher proportion of hippopotamus blood-meals in trypanosomes-infected flies identified here indicates that other wildlife species may also be important to transmission cycles. No trypanosomes associated with human disease were identified, but the high proportion of human blood-meals identified are indicative of human African trypanosomiasis transmission risk. Furthermore, this work provides data showing that Sodalis endosymbionts can is associated with increased trypanosome infection rates in endemic ecologies.Author summaryHuman and animal African trypanosomiasis are neglected tropical diseases with potential to spread to new areas. Wild animals are important reservoirs for African trypanosomes and crucial in the emergence and re-emergence of AT. Vertebrate host-vector-parasite interactions are integral to trypanosome transmission. We investigated the vertebrate blood-meals and trypanosomes-endosymbionts co-infections in tsetse flies, which have been associated with reservoirs and vector competence, respectively, on AT transmission in Kenya’s Maasai Mara National Reserve. We identified tsetse fly diversity, trypanosome and endosymbiont infection status, and vertebrate blood-meal hosts to infer potential transmission dynamics. We found that Glossina pallidipes was the major tsetse fly vector and that Trypanosoma vivax was the main trypanosome species circulating in the region. Humans, hippopotamus, and buffalo were the most frequented for blood-meals. Buffalo and hippopotamus blood-meals were identified in trypanosome infected flies. Feeding of the flies on both humans and wildlife may potentiate the risk of the human trypanosomiasis in this ecology. Additionally, we found that the endosymbiont Sodalis glossinidius is associated with higher trypanosome infection rates in wild tsetse flies. These findings emphasize the importance of understanding the interaction of tsetse flies with vertebrate blood-meal sources and their endosymbionts in the transmission and control of AT.

scholarly journals Epidemiology of tsetse flies and trypanosomes with a case study in Ethiopia

Afrika Focus ◽  
2016 ◽  
Vol 29 (2) ◽  
Author(s):  
Reta Duguma Abdi
Keyword(s):  
Serological Test ◽  
Meta Analysis ◽  
Drainage System ◽  
Diagnostic Value ◽  
Elisa Test ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Infection Prevalence ◽  
Trypanosome Infection ◽  
Monitoring Tools

The aim of this study was to quantify the abundance of tsetse ies using traditional traps and using anti-tsetse saliva ELISA test and the trypanosome infection prevalence in the tsetse ies and cattle. An area-wide tsetse fly and cattle trypanosomosis survey was conducted in Ethiopia. Groups of mice and pigs were experimentally exposed to G. m. morsitans bite to develop total saliva and rTsal ELISA tests that are capable to detect and monitor the induced anti-saliva antibodies of tsetse following host exposure to tsetse bite. A meta-analysis was conducted on prevalence of trypanosome infection in tsetse flies in the field or in laboratory-controlled conditions. Published information available since 1950s was reviewed. The findings indicated that tsetse ies and trypanosome infections of cattle are widely distributed in Ethiopia and their abundance is affected by spatial factors such as altitude, river drainage system, local factors at PA level (presence of game reserves and land use/encroachment). There was no significant association between tsetse density and prevalence of trypanosomes in cattle. Total tsetse saliva and recombinant Tsal1 protein coated indirect ELISA are sensitive immunological probes to detect contact with tsetse flies. The new serological test at hand is a sensitive indicator that can differentiate regimens of tsetse y bites (various degree of exposure of animals) and that can also detect tsetse fly bite after a prolonged period without exposure. The overall prevalence of trypanosome infection in tsetse fly populations was 10.3% and 31.0% for the eld survey data and laboratory experiment data, respectively. Both spatial (country) and temporal (year of pub- lication) variation are noticed in trypanosome infection prevalence of eld collected tsetse flies. The lack of association between tsetse density and prevalence of trypanosomes in cattle needs further investigation on the role of Tabanus and Stomoxys for mechanical trypanosome transmission. Due to the ongoing interventions, the vector could decline to a low level beyond the fly catching capacity by traps. The current serological ELISA test could be an important surveil- lance tool with sensitive diagnostic value. Key words: cattle trypanosomosis, tsetse fly abundance, tsetse infections, tsetse monitoring tools 

scholarly journals A fine-tuned vector-parasite dialogue in tsetse’s cardia determines peritrophic matrix integrity and trypanosome transmission success

2017 ◽  
Author(s):  
Aurélien Vigneron ◽  
Emre Aksoy ◽  
Brian L Weiss ◽  
Xiaoli Bing ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Structural Integrity ◽  
Control Strategies ◽  
Tsetse Flies ◽  
Parasite Transmission ◽  
Peritrophic Matrix ◽  
Oxygen Intermediates ◽  
African Trypanosomes ◽  
Transmission Cycle ◽  
Transmission Success

AbstractArthropod vectors have multiple physical and immunological barriers that impede the development and transmission of parasites to new vertebrate hosts. These barriers include the peritrophic matrix (PM), a chitinous barrier that separates the blood bolus from the midgut epithelia and inturn, modulates vector-microbiota interactions. In tsetse flies, a sleeve-like PM is continuously produced by the cardia organ located at the fore- and midgut junction. African trypanosomes, Trypanosoma brucei, must bypass the PM twice; first to colonize the midgut and secondly to reach the salivary glands (SG), to complete their transmission cycle in tsetse. However, not all flies with midgut infections develop mammalian transmissible SG infections - the reasons for which are unclear. Here, we used transcriptomics, microscopy and functional genomics analyses to understand the factors that regulate parasite migration from midgut to SG. In flies with midgut infections only, parasites fail to cross the PM as they are eliminated from the cardia by reactive oxygen intermediates (ROIs) - albeit at the expense of collateral cytotoxic damage to the cardia. In flies with midgut and SG infections, expression of genes encoding components of the PM is reduced in the cardia, and structural integrity of the PM barrier is compromised. Under these circumstances trypanosomes traverse through the newly secreted and compromised PM. The process of PM attrition that enables the parasites to re-enter into the midgut lumen is apparently mediated by components of the parasites residing in the cardia. Thus, a fine-tuned dialogue between tsetse and trypanosomes at the cardia determines the outcome of PM integrity and trypanosome transmission success.Author summaryInsects are responsible for transmission of parasites that cause deadly diseases in humans and animals. Understanding the key factors that enhance or interfere with parasite transmission processes can result in new control strategies. Here, we report that a proportion of tsetse flies with African trypanosome infections in their midgut can prevent parasites from migrating to the salivary glands, albeit at the expense of collateral damage. In a subset of flies with gut infections, the parasites manipulate the integrity of a midgut barrier, called the peritrophic matrix, and reach the salivary glands for transmission to the next mammal. Either targeting parasite manipulative processes or enhancing peritrophic matrix integrity could reduce parasite transmission.

scholarly journals Epidemiology of tsetse flies and trypanosomes with a case study in Ethiopia

Afrika Focus ◽  
2016 ◽  
Vol 29 (2) ◽  
pp. 109-116
Author(s):  
Reta Duguma Abdi
Keyword(s):  
Serological Test ◽  
Meta Analysis ◽  
Drainage System ◽  
Diagnostic Value ◽  
Elisa Test ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Infection Prevalence ◽  
Trypanosome Infection

The aim of this study was to quantify the abundance of tsetse flies using traditional traps and using anti-tsetse saliva ELISA test and the trypanosome infection prevalence in the tsetse flies and cattle. An area-wide tsetse fly and cattle trypanosomosis survey was conducted in Ethiopia. Groups of mice and pigs were experimentally exposed to G. m. morsitans bite to develop total saliva and rTsal ELISA tests that are capable to detect and monitor the induced anti-saliva antibodies of tsetse following host exposure to tsetse bite. A meta-analysis was conducted on prevalence of trypanosome infection in tsetse flies in the field or in laboratory-controlled conditions. Published information available since 1950s was reviewed. The findings indicated that tsetse flies and trypanosome infections of cattle are widely distributed in Ethiopia and their abundance is affected by spatial factors such as altitude, river drainage system, local factors at PA level (presence of game reserves and land use/encroachment). There was no significant association between tsetse density and prevalence of trypanosomes in cattle. Total tsetse saliva and recombinant Tsal1 protein coated indirect ELISA are sensitive immunological probes to detect contact with tsetse flies. The new serological test at hand is a sensitive indicator that can differentiate regimens of tsetse fly bites (various degree of exposure of animals) and that can also detect tsetse fly bite after a prolonged period without exposure. The overall prevalence of trypanosome infection in tsetse fly populations was 10.3% and 31.0% for the field survey data and laboratory experiment data, respectively. Both spatial (country) and temporal (year of publication) variation are noticed in trypanosome infection prevalence of field collected tsetse flies. The lack of association between tsetse density and prevalence of trypanosomes in cattle needs further investigation on the role of Tabanus and Stomoxys for mechanical trypanosome transmission. Due to the ongoing interventions, the vector could decline to a low level beyond the fly catching capacity by traps. The current serological ELISA test could be an important surveillance tool with sensitive diagnostic value.

scholarly journals The effect of starvation on the susceptibility of teneral and non-teneral tsetse flies to trypanosome infection

2006 ◽  
Vol 20 (4) ◽  
pp. 388-392 ◽  
Author(s):  
C. KUBI ◽  
J. VAN DEN ABBEELE ◽  
R. DE DEKEN ◽  
T. MARCOTTY ◽  
P. DORNY ◽  
...  
Keyword(s):  
Tsetse Flies ◽  
Trypanosome Infection

scholarly journals Glucose Signaling Is Important for Nutrient Adaptation during Differentiation of Pleomorphic African Trypanosomes

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Yijian Qiu ◽  
Jillian E. Milanes ◽  
Jessica A. Jones ◽  
Rooksana E. Noorai ◽  
Vijay Shankar ◽  
...  
Keyword(s):  
Life Cycle ◽  
Glucose Sensing ◽  
Negative Regulator ◽  
Bloodstream Form ◽  
Tsetse Flies ◽  
Insect Vector ◽  
Rapid Reduction ◽  
African Trypanosomes ◽  
Procyclic Form ◽  
African Trypanosome

ABSTRACT The African trypanosome has evolved mechanisms to adapt to changes in nutrient availability that occur during its life cycle. During transition from mammalian blood to insect vector gut, parasites experience a rapid reduction in environmental glucose. Here we describe how pleomorphic parasites respond to glucose depletion with a focus on parasite changes in energy metabolism and growth. Long slender bloodstream form parasites were rapidly killed as glucose concentrations fell, while short stumpy bloodstream form parasites persisted to differentiate into the insect-stage procyclic form parasite. The rate of differentiation was lower than that triggered by other cues but reached physiological rates when combined with cold shock. Both differentiation and growth of resulting procyclic form parasites were inhibited by glucose and nonmetabolizable glucose analogs, and these parasites were found to have upregulated amino acid metabolic pathway component gene expression. In summary, glucose transitions from the primary metabolite of the blood-stage infection to a negative regulator of cell development and growth in the insect vector, suggesting that the hexose is not only a key metabolic agent but also an important signaling molecule. IMPORTANCE As the African trypanosome Trypanosoma brucei completes its life cycle, it encounters many different environments. Adaptation to these environments includes modulation of metabolic pathways to parallel the availability of nutrients. Here, we describe how the blood-dwelling life cycle stages of the African trypanosome, which consume glucose to meet their nutritional needs, respond differently to culture in the near absence of glucose. The proliferative long slender parasites rapidly die, while the nondividing short stumpy parasite remains viable and undergoes differentiation to the next life cycle stage, the procyclic form parasite. Interestingly, a sugar analog that cannot be used as an energy source inhibited the process. Furthermore, the growth of procyclic form parasite that resulted from the event was inhibited by glucose, a behavior that is similar to that of parasites isolated from tsetse flies. Our findings suggest that glucose sensing serves as an important modulator of nutrient adaptation in the parasite.

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