scholarly journals Insect Stage-Specific Adenylate Cyclases Regulate Social Motility in African Trypanosomes

2014 ◽  
Vol 14 (1) ◽  
pp. 104-112 ◽  
Author(s):  
Miguel A. Lopez ◽  
Edwin A. Saada ◽  
Kent L. Hill
Keyword(s):  
Adenylate Cyclase ◽  
Drug Targets ◽  
Catalytic Domain ◽  
Cell Communication ◽  
Tsetse Fly ◽  
Microbial Pathogens ◽  
Group Level ◽  
Content Type ◽  
African Trypanosomes ◽  
Social Motility

ABSTRACTSophisticated systems for cell-cell communication enable unicellular microbes to act as multicellular entities capable of group-level behaviors that are not evident in individuals. These group behaviors influence microbe physiology, and the underlying signaling pathways are considered potential drug targets in microbial pathogens.Trypanosoma bruceiis a protozoan parasite that causes substantial human suffering and economic hardship in some of the most impoverished regions of the world.T. bruceilives on host tissue surfaces during transmission through its tsetse fly vector, and cultivation on surfaces causes the parasites to assemble into multicellular communities in which individual cells coordinate their movements in response to external signals. This behavior is termed “social motility,” based on its similarities with surface-induced social motility in bacteria, and it demonstrates that trypanosomes are capable of group-level behavior. Mechanisms governingT. bruceisocial motility are unknown. Here we report that a subset of receptor-type adenylate cyclases (ACs) in the trypanosome flagellum regulate social motility. RNA interference-mediated knockdown of adenylate cyclase 6 (AC6), or dual knockdown of AC1 and AC2, causes a hypersocial phenotype but has no discernible effect on individual cells in suspension culture. Mutation of the AC6 catalytic domain phenocopies AC6 knockdown, demonstrating that loss of adenylate cyclase activity is responsible for the phenotype. Notably, knockdown of other ACs did not affect social motility, indicating segregation of AC functions. These studies reveal interesting parallels in systems that control social behavior in trypanosomes and bacteria and provide insight into a feature of parasite biology that may be exploited for novel intervention strategies.

scholarly journals High-throughput decoding of drug targets and drug resistance mechanisms in African trypanosomes

Parasitology ◽  
2013 ◽  
Vol 141 (1) ◽  
pp. 77-82 ◽  
Author(s):  
DAVID HORN
Keyword(s):  
Drug Resistance ◽  
High Throughput ◽  
Drug Targets ◽  
Sequence Data ◽  
Resistance Mechanisms ◽  
New Drugs ◽  
Drug Uptake ◽  
Microbial Pathogens ◽  
African Trypanosomes ◽  
Genome Scale

SUMMARYThe availability of genome sequence data has facilitated the development of high-throughput genetic screening approaches in microbial pathogens. In the African trypanosome, Trypanosoma brucei, genome-scale RNA interference screens have proven particularly effective in this regard. These genetic screens allow for identification of the genes that contribute to a particular pathway or mechanisms of interest. The approach has been used to assess loss-of-fitness, revealing the genes and proteins required for parasite viability and growth. The outputs from these screens predict essential and dispensable genes and facilitate drug target prioritization efforts. The approach has also been used to assess resistance to anti-trypanosomal drugs, revealing the genes and proteins that facilitate drug uptake and action. These outputs also highlight likely mechanisms underlying clinically relevant drug resistance. I first review these findings in the context of what we know about current drugs. I then describe potential contributions that these high-throughput approaches could make to the development and implementation of new drugs.

scholarly journals Mutualist-Provisioned Resources Impact Vector Competency

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Rita V. M. Rio ◽  
Anna K. S. Jozwick ◽  
Amy F. Savage ◽  
Afsoon Sabet ◽  
Aurelien Vigneron ◽  
...  
Keyword(s):  
Life Cycle ◽  
Disease Transmission ◽  
Tsetse Fly ◽  
Parasite Development ◽  
Vitamin B ◽  
Insect Vector ◽  
Trypanosome Infection ◽  
Content Type ◽  
African Trypanosomes ◽  
Vector Competency

ABSTRACT Many symbionts supplement their host’s diet with essential nutrients. However, whether these nutrients also enhance parasitism is unknown. In this study, we investigated whether folate (vitamin B9) production by the tsetse fly (Glossina spp.) essential mutualist, Wigglesworthia, aids auxotrophic African trypanosomes in completing their life cycle within this obligate vector. We show that the expression of Wigglesworthia folate biosynthesis genes changes with the progression of trypanosome infection within tsetse. The disruption of Wigglesworthia folate production caused a reduction in the percentage of flies that housed midgut (MG) trypanosome infections. However, decreased folate did not prevent MG trypanosomes from migrating to and establishing an infection in the fly’s salivary glands, thus suggesting that nutrient requirements vary throughout the trypanosome life cycle. We further substantiated that trypanosomes rely on symbiont-generated folate by feeding this vitamin to Glossina brevipalpis, which exhibits low trypanosome vector competency and houses Wigglesworthia incapable of producing folate. Folate-supplemented G. brevipalpis flies were significantly more susceptible to trypanosome infection, further demonstrating that this vitamin facilitates parasite infection establishment. Our cumulative results provide evidence that Wigglesworthia provides a key metabolite (folate) that is “hijacked” by trypanosomes to enhance their infectivity, thus indirectly impacting tsetse species vector competency. Parasite dependence on symbiont-derived micronutrients, which likely also occurs in other arthropod vectors, represents a relationship that may be exploited to reduce disease transmission. IMPORTANCE Parasites elicit several physiological changes in their host to enhance transmission. Little is known about the functional association between parasitism and microbiota-provisioned resources typically dedicated to animal hosts and how these goods may be rerouted to optimize parasite development. This study is the first to identify a specific symbiont-generated metabolite that impacts insect vector competence by facilitating parasite establishment and, thus, eventual transmission. Specifically, we demonstrate that the tsetse fly obligate mutualist Wigglesworthia provisions folate (vitamin B9) that pathogenic African trypanosomes exploit in an effort to successfully establish an infection in the vector’s MG. This process is essential for the parasite to complete its life cycle and be transmitted to a new vertebrate host. Disrupting metabolic contributions provided by the microbiota of arthropod disease vectors may fuel future innovative control strategies while also offering minimal nontarget effects.

scholarly journals Vitamin B6Generated by Obligate Symbionts Is Critical for Maintaining Proline Homeostasis and Fecundity in Tsetse Flies

2014 ◽  
Vol 80 (18) ◽  
pp. 5844-5853 ◽  
Author(s):  
Veronika Michalkova ◽  
Joshua B. Benoit ◽  
Brian L. Weiss ◽  
Geoffrey M. Attardo ◽  
Serap Aksoy
Keyword(s):  
Pyridoxal Phosphate ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Vitamin B ◽  
Lactation Period ◽  
Content Type ◽  
African Trypanosomes ◽  
Microbial Extracts ◽  
Lactating Females ◽  
Interfering Rna

ABSTRACTThe viviparous tsetse fly utilizes proline as a hemolymph-borne energy source. In tsetse, biosynthesis of proline from alanine involves the enzyme alanine-glyoxylate aminotransferase (AGAT), which requires pyridoxal phosphate (vitamin B6) as a cofactor. This vitamin can be synthesized by tsetse's obligate symbiont,Wigglesworthia glossinidia. In this study, we examined the role ofWigglesworthia-produced vitamin B6for maintenance of proline homeostasis, specifically during the energetically expensive lactation period of the tsetse's reproductive cycle. We found that expression ofagat, as well as genes involved in vitamin B6metabolism in both host and symbiont, increases in lactating flies. Removal of symbionts via antibiotic treatment of flies (aposymbiotic) led to hypoprolinemia, reduced levels of vitamin B6in lactating females, and decreased fecundity. Proline homeostasis and fecundity recovered partially when aposymbiotic tsetse were fed a diet supplemented with either yeast orWigglesworthiaextracts. RNA interference-mediated knockdown ofagatin wild-type flies reduced hemolymph proline levels to that of aposymbiotic females. Aposymbiotic flies treated withagatshort interfering RNA (siRNA) remained hypoprolinemic even upon dietary supplementation with microbial extracts or B vitamins. Flies infected with parasitic African trypanosomes display lower hemolymph proline levels, suggesting that the reduced fecundity observed in parasitized flies could result from parasite interference with proline homeostasis. This interference could be manifested by competition between tsetse and trypanosomes for vitamins, proline, or other factors involved in their synthesis. Collectively, these results indicate that the presence ofWigglesworthiain tsetse is critical for the maintenance of proline homeostasis through vitamin B6production.

scholarly journals “Wigglesworthia morsitans” Folate (Vitamin B9) Biosynthesis Contributes to Tsetse Host Fitness

2015 ◽  
Vol 81 (16) ◽  
pp. 5375-5386 ◽  
Author(s):  
Anna K. Snyder ◽  
Rita V. M. Rio
Keyword(s):  
Host Species ◽  
Tsetse Fly ◽  
Vitamin B ◽  
Biological Traits ◽  
Evolutionary Time ◽  
Content Type ◽  
African Trypanosomes ◽  
Vitamin B9 ◽  
Obligate Mutualism ◽  
Species Specific

ABSTRACTClosely related ancient endosymbionts may retain minor genomic distinctions through evolutionary time, yet the biological relevance of these small pockets of unique loci remains unknown. The tsetse fly (Diptera: Glossinidae), the sole vector of lethal African trypanosomes (Trypanosomaspp.), maintains an ancient and obligate mutualism with species belonging to the gammaproteobacteriumWigglesworthia. Extensive concordant evolution with associatedWigglesworthiaspecies has occurred through tsetse species radiation. Accordingly, the retention of unique symbiont loci betweenWigglesworthiagenomes may prove instrumental toward host species-specific biological traits. Genome distinctions between “Wigglesworthiamorsitans” (harbored withinGlossina morsitansbacteriomes) and the basal speciesWigglesworthia glossinidia(harbored withinGlossina brevipalpisbacteriomes) include the retention of chorismate and downstream folate (vitamin B9) biosynthesis capabilities, contributing to distinct symbiont metabolomes. Here, we demonstrate that theseW. morsitanspathways remain functionally intact, with folate likely being systemically disseminated through a synchronously expressed tsetse folate transporter within bacteriomes. The folate produced byW. morsitansis demonstrated to be pivotal forG. morsitanssexual maturation and reproduction. Modest differences between ancient symbiont genomes may still play key roles in the evolution of their host species, particularly if loci are involved in shaping host physiology and ecology. Enhanced knowledge of theWigglesworthia-tsetse mutualism may also provide novel and specific avenues for vector control.

scholarly journals Insight into the Transmission Biology and Species-Specific Functional Capabilities of Tsetse (Diptera: Glossinidae) Obligate Symbiont Wigglesworthia

mBio ◽  
2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Rita V. M. Rio ◽  
Rebecca E. Symula ◽  
Jingwen Wang ◽  
Claudia Lohs ◽  
Yi-neng Wu ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Host Species ◽  
Tsetse Fly ◽  
Sister Species ◽  
Tsetse Flies ◽  
Specific Gene ◽  
Glossina Morsitans ◽  
Content Type ◽  
African Trypanosomes ◽  
Species Specific

ABSTRACT Ancient endosymbionts have been associated with extreme genome structural stability with little differentiation in gene inventory between sister species. Tsetse flies (Diptera: Glossinidae) harbor an obligate endosymbiont, Wigglesworthia, which has coevolved with the Glossina radiation. We report on the ~720-kb Wigglesworthia genome and its associated plasmid from Glossina morsitans morsitans and compare them to those of the symbiont from Glossina brevipalpis. While there was overall high synteny between the two genomes, a large inversion was noted. Furthermore, symbiont transcriptional analyses demonstrated host tissue and development-specific gene expression supporting robust transcriptional regulation in Wigglesworthia, an unprecedented observation in other obligate mutualist endosymbionts. Expression and immunohistochemistry confirmed the role of flagella during the vertical transmission process from mother to intrauterine progeny. The expression of nutrient provisioning genes (thiC and hemH) suggests that Wigglesworthia may function in dietary supplementation tailored toward host development. Furthermore, despite extensive conservation, unique genes were identified within both symbiont genomes that may result in distinct metabolomes impacting host physiology. One of these differences involves the chorismate, phenylalanine, and folate biosynthetic pathways, which are uniquely present in Wigglesworthia morsitans. Interestingly, African trypanosomes are auxotrophs for phenylalanine and folate and salvage both exogenously. It is possible that W. morsitans contributes to the higher parasite susceptibility of its host species. IMPORTANCE Genomic stasis has historically been associated with obligate endosymbionts and their sister species. Here we characterize the Wigglesworthia genome of the tsetse fly species Glossina morsitans and compare it to its sister genome within G. brevipalpis. The similarity and variation between the genomes enabled specific hypotheses regarding functional biology. Expression analyses indicate significant levels of transcriptional regulation and support development- and tissue-specific functional roles for the symbiosis previously not observed in obligate mutualist symbionts. Retention of the genetically expensive flagella within these small genomes was demonstrated to be significant in symbiont transmission and tailored to the unique tsetse fly reproductive biology. Distinctions in metabolomes were also observed. We speculate an additional role for Wigglesworthia symbiosis where infections with pathogenic trypanosomes may depend upon symbiont species-specific metabolic products and thus influence the vector competence traits of different tsetse fly host species.

scholarly journals OmpA-Mediated Biofilm Formation Is Essential for the Commensal Bacterium Sodalis glossinidius To Colonize the Tsetse Fly Gut

2012 ◽  
Vol 78 (21) ◽  
pp. 7760-7768 ◽  
Author(s):  
Michele A. Maltz ◽  
Brian L. Weiss ◽  
Michelle O'Neill ◽  
Yineng Wu ◽  
Serap Aksoy
Keyword(s):  
Immune System ◽  
Pathogenic Bacteria ◽  
Tsetse Fly ◽  
Symbiotic Bacteria ◽  
Tsetse Flies ◽  
Host Immune System ◽  
Content Type ◽  
African Trypanosomes ◽  
Sodalis Glossinidius

ABSTRACTMany bacteria successfully colonize animals by forming protective biofilms. Molecular processes that underlie the formation and function of biofilms in pathogenic bacteria are well characterized. In contrast, the relationship between biofilms and host colonization by symbiotic bacteria is less well understood. Tsetse flies (Glossinaspp.) house 3 maternally transmitted symbionts, one of which is a commensal (Sodalis glossinidius) found in several host tissues, including the gut. We determined thatSodalisforms biofilms in the tsetse gut and that this process is influenced by theSodalisouter membrane protein A (OmpA). MutantSodalisstrains that do not produce OmpA (SodalisΔOmpA mutants) fail to form biofilmsin vitroand are unable to colonize the tsetse gut unless endogenous symbiotic bacteria are present. Our data indicate that in the absence of biofilms,SodalisΔOmpA mutant cells are exposed to and eliminated by tsetse's innate immune system, suggesting that biofilms helpSodalisevade the host immune system. Tsetse is the sole vector of pathogenic African trypanosomes, which also reside in the fly gut. Acquiring a better understanding of the dynamics that promoteSodaliscolonization of the tsetse gut may enhance the development of novel disease control strategies.

scholarly journals Social Motility of African Trypanosomes Is a Property of a Distinct Life-Cycle Stage That Occurs Early in Tsetse Fly Transmission

2014 ◽  
Vol 10 (10) ◽  
pp. e1004493 ◽  
Author(s):  
Simon Imhof ◽  
Sebastian Knüsel ◽  
Kapila Gunasekera ◽  
Xuan Lan Vu ◽  
Isabel Roditi
Keyword(s):  
Life Cycle ◽  
Life Cycle Stage ◽  
Tsetse Fly ◽  
African Trypanosomes ◽  
Social Motility

scholarly journals Role of CD11b/CD18 in the Process of Intoxication by the Adenylate Cyclase Toxin of Bordetella pertussis

2011 ◽  
Vol 80 (2) ◽  
pp. 850-859 ◽  
Author(s):  
Joshua C. Eby ◽  
Mary C. Gray ◽  
Annabelle R. Mangan ◽  
Gina M. Donato ◽  
Erik L. Hewlett
Keyword(s):  
Adenylate Cyclase ◽  
Bordetella Pertussis ◽  
Catalytic Domain ◽  
Chinese Hamster ◽  
K562 Cells ◽  
Cell Types ◽  
Target Cells ◽  
Content Type ◽  
Intracellular Atp ◽  
Adenylate Cyclase Toxin

ABSTRACTThe adenylate cyclase toxin (ACT) ofBordetella pertussisdoes not require a receptor to generate intracellular cyclic AMP (cAMP) in a broad range of cell types. To intoxicate cells, ACT binds to the cell surface, translocates its catalytic domain across the cell membrane, and converts intracellular ATP to cAMP. In cells that express the integrin CD11b/CD18 (CR3), ACT is more potent than in CR3-negative cells. We find, however, that the maximum levels of cAMP accumulation inside CR3-positive and -negative cells are comparable. To better understand how CR3 affects the generation of cAMP, we used Chinese hamster ovary and K562 cells transfected to express CR3 and examined the steps in intoxication in the presence and absence of the integrin. The binding of ACT to cells is greater in CR3-expressing cells at all concentrations of ACT, and translocation of the catalytic domain is enhanced by CR3 expression, with ∼80% of ACT molecules translocating their catalytic domain in CR3-positive cells but only 25% in CR3-negative cells. Once in the cytosol, the unregulated catalytic domain converts ATP to cAMP, and at ACT concentrations >1,000 ng/ml, the intracellular ATP concentration is <5% of that in untreated cells, regardless of CR3 expression. This depletion of ATP prevents further production of cAMP, despite the CR3-mediated enhancement of binding and translocation. In addition to characterizing the effects of CR3 on the actions of ACT, these data show that ATP consumption is yet another concentration-dependent activity of ACT that must be considered when studying how ACT affects target cells.

scholarly journals Positional Dynamics and Glycosomal Recruitment of Developmental Regulators during Trypanosome Differentiation

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Balázs Szöőr ◽  
Dorina V. Simon ◽  
Federico Rojas ◽  
Julie Young ◽  
Derrick R. Robinson ◽  
...  
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Tyrosine Phosphatase ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Metabolic Adaptation ◽  
Tsetse Flies ◽  
Content Type ◽  
African Trypanosomes ◽  
Sub Saharan

ABSTRACT Glycosomes are peroxisome-related organelles that compartmentalize the glycolytic enzymes in kinetoplastid parasites. These organelles are developmentally regulated in their number and composition, allowing metabolic adaptation to the parasite’s needs in the blood of mammalian hosts or within their arthropod vector. A protein phosphatase cascade regulates differentiation between parasite developmental forms, comprising a tyrosine phosphatase, Trypanosoma brucei PTP1 (TbPTP1), which dephosphorylates and inhibits a serine threonine phosphatase, TbPIP39, which promotes differentiation. When TbPTP1 is inactivated, TbPIP39 is activated and during differentiation becomes located in glycosomes. Here we have tracked TbPIP39 recruitment to glycosomes during differentiation from bloodstream “stumpy” forms to procyclic forms. Detailed microscopy and live-cell imaging during the synchronous transition between life cycle stages revealed that in stumpy forms, TbPIP39 is located at a periflagellar pocket site closely associated with TbVAP, which defines the flagellar pocket endoplasmic reticulum. TbPTP1 is also located at the same site in stumpy forms, as is REG9.1, a regulator of stumpy-enriched mRNAs. This site provides a molecular node for the interaction between TbPTP1 and TbPIP39. Within 30 min of the initiation of differentiation, TbPIP39 relocates to glycosomes, whereas TbPTP1 disperses to the cytosol. Overall, the study identifies a “stumpy regulatory nexus” (STuRN) that coordinates the molecular components of life cycle signaling and glycosomal development during transmission of Trypanosoma brucei. IMPORTANCE African trypanosomes are parasites of sub-Saharan Africa responsible for both human and animal disease. The parasites are transmitted by tsetse flies, and completion of their life cycle involves progression through several development steps. The initiation of differentiation between blood and tsetse fly forms is signaled by a phosphatase cascade, ultimately trafficked into peroxisome-related organelles called glycosomes that are unique to this group of organisms. Glycosomes undergo substantial remodeling of their composition and function during the differentiation step, but how this is regulated is not understood. Here we identify a cytological site where the signaling molecules controlling differentiation converge before the dispersal of one of them into glycosomes. In combination, the study provides the first insight into the spatial coordination of signaling pathway components in trypanosomes as they undergo cell-type differentiation.

scholarly journals Cyclic AMP Regulates Social Behavior in African Trypanosomes

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Michael Oberholzer ◽  
Edwin A. Saada ◽  
Kent L. Hill
Keyword(s):  
Social Behavior ◽  
Cyclic Amp ◽  
Protozoan Parasite ◽  
Wild Type ◽  
Protozoan Parasites ◽  
Content Type ◽  
African Trypanosomes ◽  
Signaling Systems ◽  
Extracellular Signals ◽  
Social Motility

ABSTRACT The protozoan parasite Trypanosoma brucei engages in surface-induced social behavior, termed social motility, characterized by single cells assembling into multicellular groups that coordinate their movements in response to extracellular signals. Social motility requires sensing and responding to extracellular signals, but the underlying mechanisms are unknown. Here we report that T. brucei social motility depends on cyclic AMP (cAMP) signaling systems in the parasite's flagellum (synonymous with cilium). Pharmacological inhibition of cAMP-specific phosphodiesterase (PDE) completely blocks social motility without impacting the viability or motility of individual cells. Using a fluorescence resonance energy transfer (FRET)-based sensor to monitor cAMP dynamics in live cells, we demonstrate that this block in social motility correlates with an increase in intracellular cAMP levels. RNA interference (RNAi) knockdown of the flagellar PDEB1 phenocopies pharmacological PDE inhibition, demonstrating that PDEB1 is required for social motility. Using parasites expressing distinct fluorescent proteins to monitor individuals in a genetically heterogeneous community, we found that the social motility defect of PDEB1 knockdowns is complemented by wild-type parasites in trans. Therefore, PDEB1 knockdown cells are competent for social motility but appear to lack a necessary factor that can be provided by wild-type cells. The combined data demonstrate that the role of cyclic nucleotides in regulating microbial social behavior extends to African trypanosomes and provide an example of transcomplementation in parasitic protozoa. IMPORTANCE In bacteria, studies of cell-cell communication and social behavior have profoundly influenced our understanding of microbial physiology, signaling, and pathogenesis. In contrast, mechanisms underlying social behavior in protozoan parasites are mostly unknown. Here we show that social behavior in the protozoan parasite Trypanosoma brucei is governed by cyclic-AMP signaling systems in the flagellum, with intriguing parallels to signaling systems that control bacterial social behavior. We also generated a T. brucei social behavior mutant and found that the mutant phenotype is complemented by wild-type cells grown in the same culture. Our findings open new avenues for dissecting social behavior and signaling in protozoan parasites and illustrate the capacity of these organisms to influence each other's behavior in mixed communities.

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