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1.
Death receptor‐mediated host cell apoptosis, a defense strategy for elimination by the immune system of parasite‐infected cells, is inhibited by Trypanosoma cruzi, the causative agent of Chagas' disease. It has previously been reported by us that, in infected cells, T. cruzi upregulates and exploits cFLIPL, a mammalian inhibitor of death receptor signaling. Here it is shown that ubiquitination of cFLIPL, leading to proteasomal degradation, is inhibited in parasite‐infected cells. The extent of expression of Itch, a protein thought to be an ubiquitin ligase for cFLIPL, was found to be equivalent in T. cruzi‐infected and in uninfected cells. However, co‐immunoprecipitation analysis showed that the interaction between cFLIPL and Itch is strongly inhibited in T. cruzi‐infected cells. This unique parasite strategy, which has not been reported in any other pathogen‐infected cells, may allow the host cell to accumulate cFLIPL, eventually resulting in the inhibition of apoptosis of T. cruzi‐infected cells. 相似文献
2.
Chronic Chagas cardiomyopathy (CCC), caused by the obligate intracellular protozoan parasite Trypanosoma cruzi, is a major cause of morbidity and mortality in Latin America. CCC begins when T. cruzi enters cardiac cells for intracellular multiplication and differentiation, a process that starts with recognition of host–cell entry receptors. However, the nature of these surface molecules and corresponding parasite counter‐receptor(s) is poorly understood. Here we show that antibodies against neurotrophin (NT) receptor TrkC, but not against family members TrkA and TrkB, prevent T. cruzi from invading primary cultures of cardiomyocytes and cardiac fibroblasts. Invasion is also selectively blocked by the TrkC ligand NT‐3, and by antagonists of Trk autophosphorylation and downstream signalling. Therefore, these results indicate that T. cruzi gets inside cardiomyocytes and cardiac fibroblasts by activating TrkC preferentially over TrkA. Accordingly, short hairpin RNA interference of TrkC (shTrkC), but not TrkA, selectively prevents T. cruzi from entering cardiac cells. Additionally, T. cruzi parasite‐derived neurotrophic factor (PDNF)/trans‐sialidase, a TrkC‐binding protein, but not family member gp85, blocks entry dose‐dependently, underscoring the specificity of PDNF as TrkC counter‐receptor in cardiaccell invasion. In contrast to invasion, competitive and shRNA inhibition studies demonstrate that T. cruzi–PDNF recognition of TrkA, but not TrkC on primary cardiomyocytes and the cardiomyocyte cell line H9c2 protects the cells against oxidative stress. Thus, this study shows that T. cruzi via PDNF favours neurotrophin receptor TrkC for cardiac cell entry and TrkA for cardiomyocyte protection against oxidative stress, and suggests a new therapeutic opportunity in PDNF and/or fragments thereof for CCC therapy as entry inhibitors and/or cardioprotection agonists. 相似文献
3.
Soluble N‐ethylmaleimide‐sensitive factor attachment protein receptors required during Trypanosoma cruzi parasitophorous vacuole development
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Juan Agustín Cueto María Cristina Vanrell Betiana Nebaí Salassa Sébastien Nola Thierry Galli María Isabel Colombo Patricia Silvia Romano 《Cellular microbiology》2017,19(6)
Trypanosoma cruzi, the etiologic agent of Chagas disease, is an obligate intracellular parasite that exploits different host vesicular pathways to invade the target cells. Vesicular and target soluble N‐ethylmaleimide‐sensitive factor attachment protein receptors (SNAREs) are key proteins of the intracellular membrane fusion machinery. During the early times of T. cruzi infection, several vesicles are attracted to the parasite contact sites in the plasma membrane. Fusion of these vesicles promotes the formation of the parasitic vacuole and parasite entry. In this work, we study the requirement and the nature of SNAREs involved in the fusion events that take place during T. cruzi infection. Our results show that inhibition of N‐ethylmaleimide‐sensitive factor protein, a protein required for SNARE complex disassembly, impairs T. cruzi infection. Both TI‐VAMP/VAMP7 and cellubrevin/VAMP3, two v‐SNAREs of the endocytic and exocytic pathways, are specifically recruited to the parasitophorous vacuole membrane in a synchronized manner but, although VAMP3 is acquired earlier than VAMP7, impairment of VAMP3 by tetanus neurotoxin fails to reduce T. cruzi infection. In contrast, reduction of VAMP7 activity by expression of VAMP7's longin domain, depletion by small interfering RNA or knockout, significantly decreases T. cruzi infection susceptibility as a result of a minor acquisition of lysosomal components to the parasitic vacuole. In addition, overexpression of the VAMP7 partner Vti1b increases the infection, whereas expression of a KIF5 kinesin mutant reduces VAMP7 recruitment to vacuole and, concomitantly, T. cruzi infection. Altogether, these data support a key role of TI‐VAMP/VAMP7 in the fusion events that culminate in the T. cruzi parasitophorous vacuole development. 相似文献
4.
Xiaoyan Zhao Praveen Kumar Sheena Shah‐Simpson Kacey L. Caradonna Niels Galjart Crystal Teygong Ira Blader Torsten Wittmann Barbara A. Burleigh 《Cellular microbiology》2013,15(4):571-584
Mammalian cell invasion by the protozoan parasite Trypanosoma cruzi involves host cell microtubule dynamics. Microtubules support kinesin‐dependent anterograde trafficking of host lysosomes to the cell periphery where targeted lysosome exocytosis elicits remodelling of the plasma membrane and parasite invasion. Here, a novel role for microtubule plus‐end tracking proteins (+TIPs) in the co‐ordination of T. cruzi trypomastigote internalization and post‐entry events is reported. Acute silencing of CLASP1, a +TIP that participates in microtubule stabilization at the cell periphery, impairs trypomastigote internalization without diminishing the capacity for calcium‐regulated lysosome exocytosis. Subsequent fusion of the T. cruzi vacuole with host lysosomes and its juxtanuclear positioning are also delayed in CLASP1‐depleted cells. These post‐entry phenotypes correlate with a generalized impairment of minus‐end directed transport of lysosomes in CLASP1 knock‐down cells and mimic the effects ofdynactin disruption. Consistent with GSK3β acting as a negative regulator of CLASP function, inhibition of GSK3β activity enhances T. cruzi entry in a CLASP1‐dependent manner and expression of constitutively active GSK3β dampens infection. This study provides novel molecular insights into the T. cruzi infection process, emphasizing functional links between parasite‐elicited signalling, host microtubule plus‐end tracking proteins and dynein‐based retrograde transport. Highlighted in this work is a previously unrecognized role for CLASPs in dynamic lysosome positioning, an important aspect of the nutrient sensing response in mammalian cells. 相似文献
5.
Marie‐Pierre Hasne Isabelle Coppens Radika Soysa Buddy Ullman 《Molecular microbiology》2010,76(1):78-91
Whereas mammalian cells and most other organisms can synthesize polyamines from basic amino acids, the protozoan parasite Trypanosoma cruzi is incapable of polyamine biosynthesis de novo and therefore obligatorily relies upon putrescine acquisition from the host to meet its nutritional requirements. The cell surface proteins that mediate polyamine transport into T. cruzi, as well as most eukaryotes, however, have by‐in‐large eluded discovery at the molecular level. Here we report the identification and functional characterization of two polyamine transporters, TcPOT1.1 and TcPOT1.2, encoded by alleles from two T. cruzi haplotypes. Overexpression of the TcPOT1.1 and TcPOT1.2 genes in T. cruzi epimastigotes revealed that TcPOT1.1 and TcPOT1.2 were high‐affinity transporters that recognized both putrescine and cadaverine but not spermidine or spermine. Furthermore, the activities and subcellular locations of both TcPOT1.1 and TcPOT1.2 in intact parasites were profoundly influenced by extracellular putrescine availability. These results establish TcPOT1.1 and TcPOT1.2 as key components of the T. cruzi polyamine transport pathway, an indispensable nutritional function for the parasite that may be amenable to therapeutic manipulation. 相似文献
6.
Grieves JL Hubbard GB Williams JT Vandeberg JL Dick EJ López-Alvarenga JC Schlabritz-Loutsevitch NE 《Journal of medical primatology》2008,37(6):318-328
Background Congenital transmission of Trypanosoma cruzi has been described in humans and experimental work has been conducted with mice, but not with non‐human primates (NHPs). Methods We conducted a retrospective study of female baboons (Papio hamadryas spp.) naturally seropositive or seronegative for T. cruzi with history of fetal loss, and we report a stillbirth in a cynomolgus macaque (Macaca fascicularis) with placental T. cruzi amastigotes. Results There were no differences in menstrual cycle parameters and the number of fetal losses between seropositive and seronegative baboons with history of fetal loss. The amount of parasite DNA detected using quantitative polymerase chain reaction (Q‐PCR) in M. fascicularis placenta was within the range detected in infected baboon tissues. Conclusions There is no evidence that chronic maternal T. cruzi infection causes fetal loss in baboons. Q‐PCR is a useful diagnostic tool to study archived NHP placentas. 相似文献
7.
Ernesto S Nakayasu Lilian L Nohara Ana Claudia T Torrecilhas Andrei V Nikolaev Igor C Almeida 《Molecular systems biology》2009,5(1)
Glycosylphosphatidylinositol (GPI) anchoring is a common, relevant posttranslational modification of eukaryotic surface proteins. Here, we developed a fast, simple, and highly sensitive (high attomole‐low femtomole range) method that uses liquid chromatography‐tandem mass spectrometry (LC‐MSn) for the first large‐scale analysis of GPI‐anchored molecules (i.e., the GPIome) of a eukaryote, Trypanosoma cruzi, the etiologic agent of Chagas disease. Our genome‐wise prediction analysis revealed that approximately 12% of T. cruzi genes possibly encode GPI‐anchored proteins. By analyzing the GPIome of T. cruzi insect‐dwelling epimastigote stage using LC‐MSn, we identified 90 GPI species, of which 79 were novel. Moreover, we determined that mucins coded by the T. cruzi small mucin‐like gene (TcSMUG S) family are the major GPI‐anchored proteins expressed on the epimastigote cell surface. TcSMUG S mucin mature sequences are short (56–85 amino acids) and highly O‐glycosylated, and contain few proteolytic sites, therefore, less likely susceptible to proteases of the midgut of the insect vector. We propose that our approach could be used for the high throughput GPIomic analysis of other lower and higher eukaryotes. 相似文献
8.
Michael D. Lewis Amanda Fortes Francisco Martin C. Taylor Hollie Burrell‐Saward Alex P. McLatchie Michael A. Miles John M. Kelly 《Cellular microbiology》2014,16(9):1285-1300
Chronic Trypanosoma cruzi infections lead to cardiomyopathy in 20–30% of cases. A causal link between cardiac infection and pathology has been difficult to establish because of a lack of robust methods to detect scarce, focally distributed parasites within tissues. We developed a highly sensitive bioluminescence imaging system based on T. cruzi expressing a novel luciferase that emits tissue‐penetrating orange‐red light. This enabled long‐term serial evaluation of parasite burdens in individual mice with an in vivo limit of detection of significantly less than 1000 parasites. Parasite distributions during chronic infections were highly focal and spatiotemporally dynamic, but did not localize to the heart. End‐point ex vivo bioluminescence imaging allowed tissue‐specific quantification of parasite loads with minimal sampling bias. During chronic infections, the gastro‐intestinal tract, specifically the colon and stomach, was the only site where T. cruzi infection was consistently observed. Quantitative PCR‐inferred parasite loads correlated with ex vivo bioluminescence and confirmed the gut as the parasite reservoir. Chronically infected mice developed myocarditis and cardiac fibrosis, despite the absence of locally persistent parasites. These data identify the gut as a permissive niche for long‐term T. cruzi infection and show that canonical features of Chagas disease can occur without continual myocardium‐specific infection. 相似文献
9.
Replication Protein A‐1 Has a Preference for the Telomeric G‐rich Sequence in Trypanosoma cruzi
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Raphael Souza Pavani Marcela O. Vitarelli Carlos A. H. Fernandes Fabio F. Mattioli Mariana Morone Milene C. Menezes Marcos R. M. Fontes Maria Isabel N. Cano Maria Carolina Elias 《The Journal of eukaryotic microbiology》2018,65(3):345-356
Replication protein A (RPA), the major eukaryotic single‐stranded binding protein, is a heterotrimeric complex formed by RPA‐1, RPA‐2, and RPA‐3. RPA is a fundamental player in replication, repair, recombination, and checkpoint signaling. In addition, increasing evidences have been adding functions to RPA in telomere maintenance, such as interaction with telomerase to facilitate its activity and also involvement in telomere capping in some conditions. Trypanosoma cruzi, the etiological agent of Chagas disease is a protozoa parasite that appears early in the evolution of eukaryotes. Recently, we have showed that T. cruziRPA presents canonical functions being involved with DNA replication and DNA damage response. Here, we found by FISH/IF assays that T. cruziRPA localizes at telomeres even outside replication (S) phase. In vitro analysis showed that one telomeric repeat is sufficient to bind RPA‐1. Telomeric DNA induces different secondary structural modifications on RPA‐1 in comparison with other types of DNA. In addition, RPA‐1 presents a higher affinity for telomeric sequence compared to randomic sequence, suggesting that RPA may play specific roles in T. cruzi telomeric region. 相似文献
10.
Eric Dumonteil Henry Pronovost Eli F. Bierman Anna Sanford Alicia Majeau Ryan Moore Claudia Herrera 《Molecular ecology》2020,29(19):3747-3761
Integrating how biodiversity and infectious disease dynamics are linked at multiple levels and scales is highly challenging. Chagas disease is a vector‐borne disease, with specificities of the triatomine vectors and Trypanosoma cruzi parasite life histories resulting in a complex multihost and multistrain life cycle. Here, we tested the hypothesis that T. cruzi transmission cycles are shaped by triatomine host communities and gut microbiota composition by comparing the integrated interactions of Triatoma sanguisuga in southern Louisiana with feeding hosts, T. cruzi parasite and bacterial microbiota in two habitats. Bugs were collected from resident's houses and animal shelters and analysed for genetic structure, blood feeding sources, T. cruzi parasites, and bacterial diversity by PCR amplification of specific DNA markers followed by next‐generation sequencing, in an integrative metabarcoding approach. T. sanguisuga feeding host communities appeared opportunistic and defined by host abundance in each habitat, yielding distinct parasite transmission networks among hosts. The circulation of a large diversity of T. cruzi DTUs was also detected, with TcII and TcV detected for the first time in triatomines in the US. The bacterial microbiota was highly diverse and varied significantly according to the DTU infecting the bugs, indicating specific interactions among them in the gut. Expanding such studies to multiple habitats and additional triatomine species would be key to further refine our understanding of the complex life cycles of multihost, multistrain parasites such as T. cruzi, and may lead to improved disease control strategies. 相似文献
11.
Fnu Nagajyothi Mahalia S. Desruisseaux Niranjan Thiruvur Louis M. Weiss Vicki L. Braunstein Chris Albanese Mauro M. Teixeira Cecilia J. De Almeida Michael P. Lisanti Philipp E. Scherer Herbert B. Tanowitz 《Obesity (Silver Spring, Md.)》2008,16(9):1992-1997
Infection with Trypanosoma cruzi, the etiologic agent of Chagas disease is accompanied by an intense inflammatory reaction. Our laboratory group has identified adipose tissue as one of the major sites of inflammation during disease progression. Because adipose tissue is composed of many cell types, we were interested in investigating whether the adipocyte per se was a source of inflammatory mediators in this infection. Cultured adipocytes were infected with the Tulahuen strain of T. cruzi for 48–96 h. Immunoblot and quantitative PCR (qPCR) analyses demonstrated an increase in the expression of proinflammatory cytokines and chemokines, including interleukin (IL)‐1β, interferon‐γ, tumor necrosis factor‐α, CCL2, CCL5, and CXCL10 as well as an increase in the expression of Toll‐like receptors‐2 and 9 and activation of the notch pathway. Interestingly, caveolin‐1 expression was reduced while cyclin D1 and extracellular signal‐regulated kinase (ERK) expression was increased. The expression of PI3kinase and the activation of AKT (phosphorylated AKT) were increased suggesting that infection may induce components of the insulin/IGF‐1 receptor cascade. There was an infection‐associated decrease in adiponectin and peroxisome proliferator‐activated receptor‐γ (PPAR‐γ). These data provide a mechanism for the increase in the inflammatory phenotype that occurs in T. cruzi‐infected adipocytes. Overall, these data implicate the adipocyte as an important target of T. cruzi, and one which contributes significantly to the inflammatory response observed in Chagas disease. 相似文献
12.
13.
Ernesto S. Nakayasu Matthew R. Gaynor Tiago J. P. Sobreira Jeremy A. Ross Igor C. Almeida 《Proteomics》2009,9(13):3489-3506
Trypanosoma cruzi is the etiologic agent of Chagas disease, which affects millions of people in Latin America and has become a public health concern in the United States and areas of Europe. The possibility that kinase inhibitors represent novel anti‐parasitic agents is currently being explored. However, fundamental understanding of the cell‐signaling networks requires the detailed analysis of the involved phosphorylated proteins. Here, we have performed a comprehensive MS‐based phosphorylation mapping of phosphoproteins from T. cruzi epimastigote forms. Our LC‐MS/MS, dual‐stage fragmentation, and multistage activation analysis has identified 237 phosphopeptides from 119 distinct proteins. Furthermore, 220 phosphorylation sites were unambiguously mapped: 148 on serine, 57 on threonine, and 8 on tyrosine. In addition, immunoprecipitation and Western blotting analysis confirmed the presence of at least seven tyrosine‐phosphorylated proteins in T. cruzi. The identified phosphoproteins were subjected to Gene Ontology, InterPro, and BLAST analysis, and categorized based on their role in cell structure, motility, transportation, metabolism, pathogenesis, DNA/RNA/protein turnover, and signaling. Taken together, our phosphoproteomic data provide new insights into the molecular mechanisms governed by protein kinases and phosphatases in T. cruzi. We discuss the potential roles of the identified phosphoproteins in parasite physiology and drug development. 相似文献
14.
Paul N. Ulrich Noelia Lander Samarchith P. Kurup Laura Reiss Jessica Brewer Lia C. Soares Medeiros Kildare Miranda Roberto Docampo 《The Journal of eukaryotic microbiology》2014,61(2):155-165
Polyphosphate is a polymer of inorganic phosphate found in both prokaryotes and eukaryotes. Polyphosphate typically accumulates in acidic, calcium‐rich organelles known as acidocalcisomes, and recent research demonstrated that vacuolar transporter chaperone 4 catalyzes its synthesis in yeast. The human pathogens Trypanosoma brucei and T. cruzi possess vacuolar transporter chaperone 4 homologs. We demonstrate that T. cruzi vacuolar transporter chaperone 4 localizes to acidocalcisomes of epimastigotes by immunofluorescence and immuno‐electron microscopy and that the recombinant catalytic region of the T. cruzi enzyme is a polyphosphate kinase. RNA interference of the T. brucei enzyme in procyclic form parasites reduced short chain polyphosphate levels and resulted in accumulation of pyrophosphate. These results suggest that this trypanosome enzyme is an important component of a polyphosphate synthase complex that utilizes ATP to synthesize and translocate polyphosphate to acidocalcisomes in insect stages of these parasites. 相似文献
15.
Temporal fluctuation in shrub species preferences of two native rodents: The effect of infection status on habitat use
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M. Isabel Donoso Francisco E. Fonturbel Rocío A. Cares Esteban Oda Patricia A. Ramirez Carezza Botto‐Mahan 《Austral ecology》2016,41(5):512-518
Small mammals use plant species for gathering food resources and for shelter. Preferences for certain plant species are related to nutritional restrictions and behavioural patterns, which could be altered in the presence of an infectious disease. Several native small mammals are part of the wild cycle of the protozoan Trypanosoma cruzi, responsible for Chagas disease in humans. This is a vector‐borne disease transmitted by insects of the subfamily Triatominae. We examined the effect of T. cruzi infection status on the use and preference patterns of shrub species by two native rodent species: Octodon degus and Phyllotis darwini. This study was conducted during four sampling years (2010–2013) in a hyper‐endemic zone of Chagas disease located in a semiarid Mediterranean ecosystem. We captured individuals of 599 O. degus and 575 P. darwini (89% of the total captures), which were related to nine shrub species and examined for T. cruzi infection. In a community‐level analysis, infected and non‐infected O. degus used individual shrub species within the shrub community significantly non‐randomly relative to their availability; the same pattern was detected for non‐infected P. darwini individuals, whereas infected individuals used the shrub community according to the abundance of each shrub species. Examining individual preferences, both rodents showed a strong preference for Flourensia thurifera and Colliguaja odorifera regardless of their infection status. Preferences for specific shrub species were variable among years, showing a ‘core’ of preferred shrub species and variable levels of use of the remaining ones. Our results show that T. cruzi infection in wild small mammals can modify habitat use patterns and preferences for certain shrub species, probably affecting processes acting at community level. 相似文献
16.
Trypanosoma cruzi is the kinetoplastid protozoan parasite that causes human Chagas disease, a chronic disease with complex outcomes including severe cardiomyopathy and sudden death. In mammalian hosts, T. cruzi colonises a wide range of tissues and cell types where it replicates within the host cell cytoplasm. Like all intracellular pathogens, T. cruzi amastigotes must interact with its immediate host cell environment in a manner that facilitates access to nutrients and promotes a suitable niche for replication and survival. Although potentially exploitable to devise strategies for pathogen control, fundamental knowledge of the host pathways co‐opted by T. cruzi during infection is currently lacking. Here, we report that intracellular T. cruzi amastigotes establish close contact with host mitochondria via their single flagellum. Given the key bioenergetic and homeostatic roles of mitochondria, this striking finding suggests a functional role for host mitochondria in the infection process and points to the T. cruzi amastigote flagellum as an active participant in pathogenesis. Our study establishes the basis for future investigation of the molecular and functional consequences of this intriguing host–parasite interaction. 相似文献
17.
P. J. Waniek C. A. C. Araújo A. M. Jansen J. Costa 《Medical and veterinary entomology》2021,35(1):134-140
Many previous studies have shown a great phylogenetic and biological variability of Trypanosoma cruzi using different molecular and biochemical methods. Populations of T. cruzi were initially clustered into two main lineages called TcI and TcII by the size of the mini‐exon PCR product. In the present study, 33 isolates derived from three triatomine taxa, which belong to the Triatoma brasiliensis species complex (Triatoma juazeirensis, Triatoma melanica and Triatoma sherlocki); collected in three distinct areas of Bahia state were characterized by PCR. The isolates were identified by the size of the mini‐exon gene, 18S rRNA and 24Sα rRNA amplicons. T. cruzi isolates obtained in sylvatic and intradomiciliar ecotopes, derived from T. juazeirensis and T. melanica, were identified as TcI while the parasites originated from T. sherlocki were characterized as TcI and TcII genotypes, respectively. Those species are present in sylvatic ecotopes but are able to infest intradomiciliar areas. Therefore, it would be important to maintain studies in those localities of Bahia and further investigate the possibilities of Chagas disease transmission. Human disease may occur by any T. cruzi genotype and not only by TcII as it is the case in Amazonia. 相似文献
18.
Bianca Lima Ferreira Cristina Mary Orikaza Esteban Mauricio Cordero Renato Arruda Mortara 《Cellular microbiology》2016,18(6):779-783
Although imaging the live Trypanosoma cruzi parasite is a routine technique in most laboratories, identification of the parasite in infected tissues and organs has been hindered by their intrinsic opaque nature. We describe a simple method for in vivo observation of live single‐cell Trypanosoma cruzi parasites inside mammalian host tissues. BALB/c or C57BL/6 mice infected with DsRed‐CL or GFP‐G trypomastigotes had their organs removed and sectioned with surgical blades. Ex vivo organ sections were observed under confocal microscopy. For the first time, this procedure enabled imaging of individual amastigotes, intermediate forms and motile trypomastigotes within infected tissues of mammalian hosts. 相似文献
19.
Relationships between altitude,triatomine (Triatoma dimidiata) immune response and virulence of Trypanosoma cruzi,the causal agent of Chagas' disease
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J. A. DE FUENTES‐VICENTE M. CABRERA‐BRAVO J. N. ENRÍQUEZ‐VARA M. I. BUCIO‐TORRES A. E. GUTIÉRREZ‐CABRERA D. G. VIDAL‐LÓPEZ J. A. MARTÍNEZ‐IBARRA P. M. SALAZAR‐SCHETTINO A. CÓRDOBA‐AGUILAR 《Medical and veterinary entomology》2017,31(1):63-71
Little is known about how the virulence of a human pathogen varies in the environment it shares with its vector. This study focused on whether the virulence of Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae), the causal agent of Chagas' disease, is related to altitude. Accordingly, Triatoma dimidiata (Hemiptera: Reduviidae) specimens were collected at three different altitudes (300, 700 and 1400 m a.s.l.) in Chiapas, Mexico. The parasite was then isolated to infect uninfected T. dimidiata from the same altitudes, as well as female CD‐1 mice. The response variables were phenoloxidase (PO) activity, a key insect immune response, parasitaemia in mice, and amastigote numbers in the heart, oesophagus, gastrocnemius and brain of the rodents. The highest levels of PO activity, parasitaemia and amastigotes were found for Tryp. cruzi isolates sourced from 700 m a.s.l., particularly in the mouse brain. A polymerase chain reaction‐based analysis indicated that all Tryp. cruzi isolates belonged to a Tryp. cruzi I lineage. Thus, Tryp. cruzi from 700 m a.s.l. may be more dangerous than sources at other altitudes. At this altitude, T. dimidiata is more common, apparently because the conditions are more beneficial to its development. Control strategies should focus activity at altitudes around 700 m a.s.l., at least in relation to the region of the present study sites. 相似文献
20.
Recently differentiated epimastigotes from Trypanosoma cruzi are infective to the mammalian host
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Rafael Luis Kessler Víctor Tulio Contreras Newmar Pinto Marliére Alessandra Aparecida Guarneri Luz Helena Villamizar Silva Giovanny Augusto Camacho Antevere Mazzarotto Michel Batista Vanete Thomaz Soccol Marco Aurelio Krieger Christian Macagnan Probst 《Molecular microbiology》2017,104(5):712-736
Trypanosoma cruzi, the etiologic agent of Chagas disease, has a complex life cycle in which four distinct developmental forms alternate between the insect vector and the mammalian host. It is assumed that replicating epimastigotes present in the insect gut are not infective to mammalian host, a paradigm corroborated by the widely acknowledged fact that only this stage is susceptible to the complement system. In the present work, we establish a T. cruzi in vitro and in vivo epimastigogenesis model to analyze the biological aspects of recently differentiated epimastigotes (rdEpi). We show that both trypomastigote stages of T. cruzi (cell‐derived and metacyclic) are able to transform into epimastigotes (processes termed primary and secondary epimastigogenesis, respectively) and that rdEpi have striking properties in comparison to long‐term cultured epimastigotes: resistance to complement‐mediated lysis and both in vitro (cell culture) and in vivo (mouse) infectivity. Proteomics analysis of all T. cruzi stages reveled a cluster of proteins that were up‐regulated only in rdEpi (including ABC transporters and ERO1), suggesting a role for them in rdEpi virulence. The present work introduces a new experimental model for the study of host‐parasite interactions, showing that rdEpi can be infective to the mammalian host. 相似文献