Alena Zíková azikova@paru.cas.cz Institute of Parasitology, Biology Centre Ceske Budějovice Plasmodium falciparum MSP1 - The Native Antigen Company Výsledek obrázku pro trypanosoma Buněčné biologie prvoků Parazitičtí prvoci Parasitos = parasite of the classical Greek antiquity was a tolerated, but not invited co-eater during a guest meal. Parasites Parasites are organisms that live in or on another organism (host) and derive nutrients at the expense of the host. Výsledek obrázku pro parasitisms Výsledek obrázku pro tasemnice Výsledek obrázku pro trypanosoma unicellular organisms (protists) helminths (worms) arthropods The malaria-infected red blood cell. 3D illustration showing malaria parasite Plasmodium ovale in the stage of schizont Stock Illustration | Adobe Stock Stock fotografie Kožní Leishmaniáza Vřed A Detailní Pohled Na Leishmania Amastigotes – stáhnout obrázek nyní - iStock 524 Trypanosoma Images, Stock Photos, 3D objects, & Vectors | Shutterstock Plasmodium Leishmania Trypanosoma Parasitic Protozoans Toxoplasma Gondii Stock Photo - Download Image Now - Toxoplasma Gondii, Parasitic, Abscess - iStock Toxoplasma Parasitos = parasite of the classical Greek antiquity was a tolerated, but not invited co-eater during a guest meal. Parasites Parasites are organisms that live in or on another organism (host) and derive nutrients at the expense of the host. The malaria-infected red blood cell. 3D illustration showing malaria parasite Plasmodium ovale in the stage of schizont Stock Illustration | Adobe Stock Stock fotografie Kožní Leishmaniáza Vřed A Detailní Pohled Na Leishmania Amastigotes – stáhnout obrázek nyní - iStock 524 Trypanosoma Images, Stock Photos, 3D objects, & Vectors | Shutterstock Plasmodium Leishmania Trypanosoma Parasitic Protozoans Toxoplasma Gondii Stock Photo - Download Image Now - Toxoplasma Gondii, Parasitic, Abscess - iStock Toxoplasma Parasites •Global health impact: Parasitic diseases affect millions worldwide. • •Economic implications: Agricultural and livestock parasitism. • •Scientific discovery: Unveiling unique features and pathways. Important Human Parasites of the Tropics · Frontiers for Young Minds Overview of Parasitology The Relevance of Parasitology Stock fotografie Kožní Leishmaniáza Vřed A Detailní Pohled Na Leishmania Amastigotes – stáhnout obrázek nyní - iStock Stock ilustrace „3d Illustration Schistosoma Adult Haematobium Adult“ 1653073225 | Shutterstock Disease Burden in DALYs * World Health Report estimates, 2012 Disease Health burden (millions DALYs)a Deaths (per annum) Viral HIV/AIDS* 89 1.1 millions Rabies 1.46 26,400 Dengue 0.83 14,700 Bacterial Tuberculosis 36 1.6 millions Trachoma 0.33 0 Protozoal Malaria* 42 670, 000 Sleeping sickness 1.6 13,000 Chagas disease 0.6 13,000 Leishmaniasis 3.32 59,000 Helminthic Schistosomiasis 3.31 15,000 Onchorcerciasis 1.0 0 Filariasis 2.78 0 Soiled-transmitted 5.19 2,700 Disease burden Disease Burden in DALYs The burden of disease and what it means in England – UK Health Security Agency Disease Burden in DALYs Disease burden in DALYs DALYs – disability adjusted life years Communicable vs non-communicavle diseases •NEGLECTED TROPICAL DISEASES https://ourworldindata.org/burden-of-disease http://www.ipsolutionsblog.com/wp-content/uploads/2012/06/NTD-infographic-blog-size.PNG Neglected Tropical Diseases Parasites in focus Parasites in focus Garcia-Lopez & Moreira 2023 The Original Supergroups – and Where Are They Now? Five to six supergroups were originally proposed, depending on whether Opisthokonta and Amoebozoa were unified in the larger group unikonts. The name unikonts (based on a now-discarded hypothesis of a uniflagellated ancestor) was later replaced by Amorphea. The six supergroups version corresponded to the following. ›Opisthokonta includes animals, fungi, and several protist lineages that are most closely related to either animals or fungi. Opisthokonta remains a robust clade in modern phylogenies; however, it is nested within at least two larger taxa, Amorphea and Obazoa, that are frequently treated as supergroups instead. ›Amoebozoa is also still a robust group, but now is often regarded as a member of the supergroup Amorphea. Amoebozoa includes free-living amoeboid forms with lobose pseudopodia (e.g., Amoeba) but also more filose amoebae, some flagellates, and various slime molds. ›Excavata was originally proposed based on a distinctive morphology, namely a particular feeding groove form and associated cytoskeleton system, found in many enigmatic flagellated protists. Phylogenetics and phylogenomics defined three monophyletic subgroups – Discoba, Metamonada, and malawimonads – but have not consistently placed them together as a single clade. The name is now usually restricted to a Discoba–Metamonada clade (quite possibly artificial; see main text) or regarded as referring to a paraphyletic group. ›Archaeplastida are distinguished by the presence of primary plastids – the photosynthetic organelles deriving directly from cyanobacteria by endosymbiosis. The three main groups with primary plastids are the green algae and land plants, red algae (and likely their recently discovered relative Rhodelphis), and glaucophyte algae. Today, Archaeplastida is generally still considered a supergroup, although most phylogenomic analyses do not strongly support its monophyly (i.e., all three host lineages forming a single clade to the exclusion of other supergroups). ›Chromalveolata contained groups with red alga-derived secondary plastids (i.e., Alveolata, Stramenopila, Haptophyta, and Cryptophyta). This group was based on the assumption that these plastids were acquired once in a common ancestor, which was supported by plastid evidence but never strongly from the host perspective. Chromalveolata has been shown to be polyphyletic, with Alveolata and Stramenopila belonging to Sar (in TSAR), Haptophyta in Haptista, and Cryptophyta in Cryptista. ›Rhizaria was the latest addition at the time the supergroup model was proposed. It includes a wide diversity of amoebae (e.g., foraminiferans, the radiolarians, filose testate amoebae), flagellates, various parasites, and the chlorarachniophyte algae. In contrast to all other original supergroups, which were at least partly distinguished by morphological characters, Rhizaria was inferred more or less exclusively using molecular phylogenetics. It is now part of Sar (in TSAR) along with Alveolata and Stramenopila. Model Organisms in Parasitology Model organisms serve as valuable tools for understanding the biology, genetics, and pathogenic mechanisms of parasites. ›Genetic Manipulation: Ease of genetic modification facilitates the study of specific genes and their functions. › ›Short Reproductive Cycles: Allows for quick generation of experimental data and observations. › ›In Vitro Cultivation: Facilitates controlled experimentation and observation. › ›Conservation of Biological Processes: Many biological processes are conserved across species, allowing extrapolation of findings. The malaria-infected red blood cell. 3D illustration showing malaria parasite Plasmodium ovale in the stage of schizont Stock Illustration | Adobe Stock Stock fotografie Kožní Leishmaniáza Vřed A Detailní Pohled Na Leishmania Amastigotes – stáhnout obrázek nyní - iStock 524 Trypanosoma Images, Stock Photos, 3D objects, & Vectors | Shutterstock Plasmodium Leishmania Trypanosoma Parasitic Protozoans Toxoplasma Gondii Stock Photo - Download Image Now - Toxoplasma Gondii, Parasitic, Abscess - iStock Toxoplasma Model Organisms in Parasitology Model organisms serve as valuable tools for understanding the biology, genetics, and pathogenic mechanisms of parasites. ›Genetic Manipulation: Ease of genetic modification facilitates the study of specific genes and their functions. › ›Short Reproductive Cycles: Allows for quick generation of experimental data and observations. › ›In Vitro Cultivation: Facilitates controlled experimentation and observation. › ›Conservation of Biological Processes: Many biological processes are conserved across species, allowing extrapolation of findings. The malaria-infected red blood cell. 3D illustration showing malaria parasite Plasmodium ovale in the stage of schizont Stock Illustration | Adobe Stock Stock fotografie Kožní Leishmaniáza Vřed A Detailní Pohled Na Leishmania Amastigotes – stáhnout obrázek nyní - iStock 524 Trypanosoma Images, Stock Photos, 3D objects, & Vectors | Shutterstock Plasmodium Leishmania Trypanosoma Parasitic Protozoans Toxoplasma Gondii Stock Photo - Download Image Now - Toxoplasma Gondii, Parasitic, Abscess - iStock Toxoplasma SAR CLADE: ALVEOLATA (meaning "with cavities„) presence of cortical (outer-region) alveoli (sacs) Výsledek obrázku pro alveolata alveoli flattened vesicles (sacs) packed into a continuous layer just under the membrane and supporting it, typically forming a flexible pellicle Výsledek obrázku pro alveolata alveoli Paramecium putrinum SAR CLADE: ALVEOLATA (meaning "with cavities„) alveoli → ALVEOLIN Výsledek obrázku pro GOULD ET AL ALVEOLIN Výsledek obrázku pro GOULD ET AL ALVEOLIN Výsledek obrázku pro GOULD ET AL ALVEOLIN Gould et al., 2008 APICOMPLEXA APICOMPLEXA - VÝTRUSOVCI a group of structures and organelles consists of structural components and secretory organelles required for invasion of host cells during the parasitic stages of the Apicomplexan life cycle figure1 Výsledek obrázku pro apical complex electron microscopy a) Schematic enlarged view of the apical complex cytoskeleton, showing... | Download Scientific Diagram Apical complex APICOMPLEXA Apicoplast a derived non-photosynthetic plastid originated by secondary endosymbiosis (4 membranes) has its own genome essential metabolic pathways drug target Toxoplasma gondii Seeber et al., 2014 Toxoplasma gondii ›coccidia ›found worldwide ›capable of infecting virtually all warm-blooded animals (incl. birds) ›but felids such as domestic cats are the only known definitive hosts in which the parasite may undergo sexual reproduction ›one of the most common parasites in developed countries › Toxoplasmosis ›significant health consequences, particularly in immunocompromised individuals and pregnant women (risk of congenital toxoplasmosis). ›serological studies estimate that 30–50% of the global population has been exposed ›France 84% prevalence, CZ 30% prevalence Manipulation theory •Rats •Mice •Human (Ig Nobel prize to Jaroslav Flegr) Toxoplasma gondii https://cmr.asm.org/content/cmr/25/2/264/F3.large.jpg?width=800&height=600&carousel=1 https://cmr.asm.org/content/cmr/25/2/264/F3.large.jpg?width=800&height=600&carousel=1 unsporulated and sporulated oocysts SouvisejÃcà obrázek Výsledek obrázku pro tachyzoites toxoplasma gondii tachyzoites → rapid growth and replication SouvisejÃcà obrázek SouvisejÃcà obrázek bradyzoite → sessile, slow-growing form oocyst → mature oocyst containing sporozoites Toxoplasma gondii as model organism ›the best model system to study the biology of the Apicomplexa › ›life cycle can be completed in vitro ← controlled experiments to investigate various biology aspects ease of in vitro culture ›the mouse animal model is well-established ›readily amenable to genetic manipulation in the laboratory ›the high efficiency of transient and stable transfection ›gene knockout, gene tagging, and transgenic expression ›the availability of many cell markers ›advanced microscopic techniques ›functions of specific genes and pathways involved in parasite biology ›heterologous expression of apicomplexan proteins in T. gondii › › ›molecular mechanisms of host-parasite interactions, host cell invasion, and immune evasion strategies ›(← intracellular parasitsm) › ›mechanisms of drug resistance, the biology of the apicoplast › ›interactions with different hosts and the resulting pathogenesis (← wide host range) https://jcs.biologists.org/content/joces/121/9/1559/F4.large.jpg?width=800&height=600&carousel=1 IMC = the inner membrane complex A Genome-wide CRISPR Screen in Toxoplasma Identifies Essential Apicomplexan Genes Sidik et al., 2016. Cell Lourido talk on basics of Toxoplasma https://www.youtube.com/watch?v=wML68MA--Kw https://www.youtube.com/watch?v=wML68MA--Kw https://www.youtube.com/watch?v=YGTe6Kk9w8E https://www.youtube.com/watch?v=YGTe6Kk9w8E APICOMPLEXA ›Hematozoa ›many species were discovered in various hosts and classified ›mammals ~ 50 species; birds ~ 40 species; reptiles ~ 60 species ›five species that regularly infect human ›P. vivax, P. falciparum, P. malariae, P. ovale, and P. knowlesi MALARIA („mal aria“ = špatný vzduch) 300 mil infections/year 2.5 billions in endemic area Plasmodium P. falciparum ›„falx“ = „srp“ ›also called malignant or falciparum malaria ›the most dangerous form of malaria ›the highest rates of complications and mortality ›as of 2006 - an estimated 247 million human malarial infections (98% in Africa) ›almost every malarial death is caused by P. falciparum › ›disease: malignant tertian malaria (36-48h), „tropicana“ https://upload.wikimedia.org/wikipedia/en/thumb/7/75/Fever_Patterns_v1.2.svg/1920px-Fever_Patterns_ v1.2.svg.png SouvisejÃcà obrázek Výsledek obrázku pro samec symbol SouvisejÃcà obrázek Výsledek obrázku pro sporozoite plasmodium ACONOIDEA = „zoit“ lacks conoid Plasmodium spp. life cycle Výsledek obrázku pro plasmodium mosquito gut oocysts P. falciparum ›in vitro cultivation ›challenging mosquito infection („in vitro feeding“) › ›genetic manipulation has historically been challenging ›the availability of many cell markers ›advanced microscopic techniques › P. berghei ›a popular model organism for the study of human malaria ›can be genetically manipulated more easily than the species which infect humans ›the mouse animal model is well-established ›experimental cerebral malaria ›easy infection of mosquitoes incl. transmission › ›development and screening of anti-malarial drugs ›development of an effective vaccine against malaria Plasmodium as model organism https://upload.wikimedia.org/wikipedia/en/7/76/Berghei_03.png https://upload.wikimedia.org/wikipedia/commons/8/84/Liver_stage_malaria_parasite.jpg A liver cell with P. berghei expressing mCherry (red). P. berghei expression of bioluminescent reporter protein Luciferase Overview of Parasitology Classification of Parasites Parasites in focus Garcia-Lopez & Moreira 2023 The Original Supergroups – and Where Are They Now? Five to six supergroups were originally proposed, depending on whether Opisthokonta and Amoebozoa were unified in the larger group unikonts. The name unikonts (based on a now-discarded hypothesis of a uniflagellated ancestor) was later replaced by Amorphea. The six supergroups version corresponded to the following. ›Opisthokonta includes animals, fungi, and several protist lineages that are most closely related to either animals or fungi. Opisthokonta remains a robust clade in modern phylogenies; however, it is nested within at least two larger taxa, Amorphea and Obazoa, that are frequently treated as supergroups instead. ›Amoebozoa is also still a robust group, but now is often regarded as a member of the supergroup Amorphea. Amoebozoa includes free-living amoeboid forms with lobose pseudopodia (e.g., Amoeba) but also more filose amoebae, some flagellates, and various slime molds. ›Excavata was originally proposed based on a distinctive morphology, namely a particular feeding groove form and associated cytoskeleton system, found in many enigmatic flagellated protists. Phylogenetics and phylogenomics defined three monophyletic subgroups – Discoba, Metamonada, and malawimonads – but have not consistently placed them together as a single clade. The name is now usually restricted to a Discoba–Metamonada clade (quite possibly artificial; see main text) or regarded as referring to a paraphyletic group. ›Archaeplastida are distinguished by the presence of primary plastids – the photosynthetic organelles deriving directly from cyanobacteria by endosymbiosis. The three main groups with primary plastids are the green algae and land plants, red algae (and likely their recently discovered relative Rhodelphis), and glaucophyte algae. Today, Archaeplastida is generally still considered a supergroup, although most phylogenomic analyses do not strongly support its monophyly (i.e., all three host lineages forming a single clade to the exclusion of other supergroups). ›Chromalveolata contained groups with red alga-derived secondary plastids (i.e., Alveolata, Stramenopila, Haptophyta, and Cryptophyta). This group was based on the assumption that these plastids were acquired once in a common ancestor, which was supported by plastid evidence but never strongly from the host perspective. Chromalveolata has been shown to be polyphyletic, with Alveolata and Stramenopila belonging to Sar (in TSAR), Haptophyta in Haptista, and Cryptophyta in Cryptista. ›Rhizaria was the latest addition at the time the supergroup model was proposed. It includes a wide diversity of amoebae (e.g., foraminiferans, the radiolarians, filose testate amoebae), flagellates, various parasites, and the chlorarachniophyte algae. In contrast to all other original supergroups, which were at least partly distinguished by morphological characters, Rhizaria was inferred more or less exclusively using molecular phylogenetics. It is now part of Sar (in TSAR) along with Alveolata and Stramenopila. „EXCAVATA“ DISCOBA METAMONADA Euglenozoa Heterlobosea Jakobea Preaxostyla Fornicata Parabasala parasites, one group with plastids (chloroplast) alternate between flagellate and ameboid forms free living free-living or living in the hindguts of insects mostly symbiotes and parasites of animals generally intestinal commensals of insects, some human pathogens SouvisejÃcà obrázek SouvisejÃcà obrázek SouvisejÃcà obrázek „EXCAVATA“ DISCOBA METAMONADA Euglenozoa Heterlobosea Jakobea Preaxostyla Fornicata Parabasala alternate between flagellate and ameboid forms free living free-living or living in the hindguts of insects mostly symbiotes and parasites of animals generally intestinal commensals of insects, some human pathogens SouvisejÃcà obrázek SouvisejÃcà obrázek SouvisejÃcà obrázek Milíčovský rybník | Pražská příroda Sound waves of undersea earthquakes reveal changes in ocean warming Diplonemea Kinetoplastea Free-living, parasitic Free-living (in most cases) Free-living (auto- and heterotrophs) Trypanosoma brucei, T. congolense, T. vivax, causative agent of African Trypanosomiases T. cruzi, Chagas disease Leishmania spp., causative agent of leishmaniases Diplonema papillatum D. japonicum Euglena gracilis Euglenids A picture containing fabric Description automatically generated Background pattern Description automatically generated Euglenozoa each causing a distinct disease and possessing unique genetic marker(s) Kinetoplastea Free-living, parasitic Trypanosoma brucei, T. congolense, T. vivax, causative agent of African Trypanosomiases T. cruzi, Chagas disease Leishmania spp., causative agent of leishmaniases A picture containing fabric Description automatically generated Background pattern Description automatically generated ›the presence of an organelle with a large massed DNA called kinetoplast › › ›glycosomes › › ›acidocalcisoms › Ultrastructure of Trypanosoma cruzi and its interaction with host ... Arrow indicates the nucleus and arrowhead indicates the kinetoplast of T. brucei. Kinetoplastida, Trypanosomatida each causing a distinct disease and possessing unique genetic marker(s) African Trypanosomes Adapted from Lukeš et al., 2022. Trends in Parasitol. Trypanosoma brucei (T. b. brucei, T. b. gambiense, T. b. rhodesiense, T. b. evansi, T. b. equiperdum) T. congolense, T. vivax - -Human African Trypanosomiasis (HAT) -36 African states -50 millions in affected areas -Always lethal if untreated - -Animal African Trypanosomiasis (AAT) -Direct loos of livestock products -Loss of crop productivity due to loss of the animals draught power Text Description automatically generated with low confidence T. brucei life cycle Trypanosome transmission through tsetse. | Download Scientific Diagram T. brucei life cycle – insect forms development Trypanosoma brucei as model organism ›a model organism for the kinetoplastids ›in vitro culture of both bloodstream and procyclic stages ›the mouse animal model is well-established ›infection in rodents provide valuable platforms for studying disease pathogenesis, immune responses, and drug efficacy. ›well-established tools for genetic manipulation › › ›unusual nuclear architecture compared to those of other eukaryotic model organisms ›genome organization and nuclear gene expression regulation › › ›kinetoplast structure: minicircles and maxicircles ›RNA editing › ›antigenic variation › ›glycosomes → dealing changes in nutrient availability Trypanosoma cruzi T. cruzi 6 definovaných skupin, různé kmeny Zoonóza Přenášena plošticemi rodu Triatominae (kissing bugs) Geographical distribution Chagasova choroba 16-18 mil infikovaných 90 mil žijících v rizikových oblastech Akutní a chronická faze (kardio-, gastrointestinální komplikace) úmrtí až v 10% Treatment – benznidazole, nifurtimox https://www.google.com/search?sca_esv=977e94292b20825f&sxsrf=ACQVn0_C7_WU9ZA3F-gYj9bMvdkRWzttNw:171 3780308355&q=trypanosoma+cruzi+life+cycle&tbm=vid&source=lnms&prmd=ivnbz&sa=X&sqi=2&ved=2ahUKEwjZpo KUydWFAxV93AIHHf6XD58Q0pQJegQICBAB&biw=2133&bih=1050&dpr=0.9#fpstate=ive&vld=cid:d2bde252,vid:_mZIz MU10OY,st:0 https://www.google.com/search?sca_esv=977e94292b20825f&sxsrf=ACQVn0_C7_WU9ZA3F-gYj9bMvdkRWzttNw:171 3780308355&q=trypanosoma+cruzi+life+cycle&tbm=vid&source=lnms&prmd=ivnbz&sa=X&sqi=2&ved=2ahUKEwjZpo KUydWFAxV93AIHHf6XD58Q0pQJegQICBAB&biw=2133&bih=1050&dpr=0.9#fpstate=ive&vld=cid:f65593c5,vid:1ais6 9H0li8,st:0 T. cruzi trypomastigote T. cruzi amastigote MAMMMALIAN HOST INSECT VECTOR Trypanosoma cruzi life cycle Schematic illustration of T. cruzi life cycle. (1) During the blood meal, the triatomine bites a mammalian host and ingests the trypomastigotes present in the bloodstream of the mammalian host. The metacyclic trypomastigotes (2) differentiate into epimastigotes and some spheromastigotes (3). (4) In the midgut, the epimastigotes multiply by binary fission, and (5) transform into metacyclic trypomastigotes in the hindgut. (6) The metacyclic trypomastigotes are released in feces near the site of the bite wound when the insect feeds on a host. After entering the host through the wound or intact mucosal membranes, (7) the metacyclic parasites infects macrophages (8) and inside the cell, they differentiate into amastigote (9). (10) After releasing 3 the parasitophorous vacuole, (11) the amastigote multiplies in the cytoplasm. (12) Amastigotes transform into trypomastigotes and (13) they burst out of the cell. (14) Amastigotes and trypomastigotes forms. (15) Trypomastigotes (a) and (b) amastigotes infect macrophages. Adapted and reproduced from Teixeira et al., 2012 Life cycle of Trypanosoma cruzi in the gut of the insect vector. After feeding on blood containing trypomastigotes (TRY), the parasites transform in the stomach (a) into epimastigotes (EPI) and some amastigotes and spheromastigotes (SPH). In the small intestine (b) the parasites multiply and adhere to the perimicrovillar membranes of the intestinal cells. In the rectum (c) the epimastigotes multiply intensively, attach to the rectal wall and transform to metacyclic trypomastigotes which are eliminated with feces and urine (stages of T. cruzi from Ref. [10]). Trypanosoma cruzi life cycle Schematic illustration of T. cruzi life cycle. (1) During the blood meal, the triatomine bites a mammalian host and ingests the trypomastigotes present in the bloodstream of the mammalian host. The metacyclic trypomastigotes (2) differentiate into epimastigotes and some spheromastigotes (3). (4) In the midgut, the epimastigotes multiply by binary fission, and (5) transform into metacyclic trypomastigotes in the hindgut. (6) The metacyclic trypomastigotes are released in feces near the site of the bite wound when the insect feeds on a host. After entering the host through the wound or intact mucosal membranes, (7) the metacyclic parasites infects macrophages (8) and inside the cell, they differentiate into amastigote (9). (10) After releasing 3 the parasitophorous vacuole, (11) the amastigote multiplies in the cytoplasm. (12) Amastigotes transform into trypomastigotes and (13) they burst out of the cell. (14) Amastigotes and trypomastigotes forms. (15) Trypomastigotes (a) and (b) amastigotes infect macrophages. Adapted and reproduced from Teixeira et al., 2012 Life cycle of Trypanosoma cruzi in the gut of the insect vector. After feeding on blood containing trypomastigotes (TRY), the parasites transform in the stomach (a) into epimastigotes (EPI) and some amastigotes and spheromastigotes (SPH). In the small intestine (b) the parasites multiply and adhere to the perimicrovillar membranes of the intestinal cells. In the rectum (c) the epimastigotes multiply intensively, attach to the rectal wall and transform to metacyclic trypomastigotes which are eliminated with feces and urine (stages of T. cruzi from Ref. [10]). Trypanosoma cruzi life cycle https://www.youtube.com/watch?v=1ais69H0li8 Trypanosoma cruzi life cycle https://www.youtube.com/watch?v=_mZIzMU10OY Trypanosoma cruzi as model organism ›in vitro culture → parasite biology, drug susceptibility, and host interactions ›the mouse animal model is established ›disease pathogenesis, immunopathology, and vaccine development ›host-parasite interactions, and drug resistance in Chagas disease ›well-established tools for genetic manipulation ›specific genes and pathways involved in parasite biology, virulence, and drug resistance Transgenic Trypanosoma cruzi expressing GFP or DsRed. Left: mixed... | Download Scientific Diagram Transgenic Trypanosoma cruzi expressing GFP or DsRed Leishmania spp. Ilustrace „Cutaneous leishmaniasis ulcer and close-up view of Leishmania promastigotes, up, and amastigotes infected human histiocyte cells, bottom , 3D illustration“ ze služby Stock | Adobe Stock Leishmaniasis WHO 2018 Coutaneous & visceral leishmania worldwide map WHO 2018 Coutaneous & visceral leishmania worldwide map Leishmaniasis •Depending on the person infected, treatment may not be necessary. •It can speed healing and prevent further complications. •In this form of disease, the parasite enters the host through the nose, throat, and mouth. •This can cause partial or complete destruction of the mucous membrane in those regions. •Though this form of Leishmaniasis is known as the subset of Cutaneous Leishmaniasis, it is more serious. Leishmania spp. life cycle Digenetic life cycle of Leishmania: (A) Inside the sandfly, amastigotes undergo several non-infective stages before they finally differentiate into metacyclic promastigotes; (a) amastigotes enter into the sandfly (vector), while it bites an infected mammal (host), (b) amastigotes transform into replicative procyclic promastigotes (flagellated form) inside the fly abdominal midgut, (c) Procyclic stage transforms into an elongated nectomonad promastigote that attaches to the microvilli of the abdominal midgut through its flagella, (d) nectomonad then differentiates into a replicative form (leptomonad promastigote), and migrates towards the thoracic midgut, (e) leptomonad promastigotes can differentiate into either heptomonad promastigotes, or (f) metacyclic promastigotes. The haptomonad promastigotes can attach to the stomodeal valve, (g) during the second blood meal, a new replicative stage, known as retroleptomonad promastigote, exists due to reverse metacyclogenesis, where they multiply rapidly and differentiate into metacyclic promastogotes enhancing sandfly infectivity. (B) The metacyclic promastigote belongs to the infective stage that is transmitted to the mammalian host when an infected sandfly bites; (a) metacyclic promastigotes are taken up by phagocytic cells such as macrophages and neutrophils present in the skin, (b) promastigotes are internalised into phagosomes (later, it transforms into a parasitophorus vacuole), (c) promastigotes change into amastigotes inside the parasitophorus vacuole and proliferate, (d) amastigotes burst out from the phagocytes, (e) amastigotes can enter into another life cycle inside the sandfly when taken with the blood meal, or can re-infect fresh phagocytes. Leishmania as model organism Experimental accessibility ›in vitro culture → parasite biology, drug susceptibility, and host interactions ›the mouse animal model is established → gene expression, pathogenesis Genetic tractability ›relatively small genome that is genetically tractable ›genetic manipulation → gene function and impact on parasitic biology. Complex life cycle → mechanisms by which parasites adapt to different host environments Drug resistance → studying mechanisms of drug resistance and identifying new drug targets Immune evasion → various strategies to evade the host immune system → chronic infections Comparative studies → comparative genomics between Leshmania and related parasites → evolution of parasitic traits and host-parasite interactions Assessing the efficiency of parasite inoculation. Imaging and quantifying bioluminescent Leishmania parasites during infection with IVIS. Wild-type BALB/c mice were injected intradermally in the lower right flank with HBSS (mock) or transgenic Leishmania i. chagasi L. i. chagasi pIR1SAT-LUC(A). The mice were then analyzed with the IVIS imaging technology one hour after inoculation. A) A black and white photograph of the mice was taken immediately before the luminescent signal (light intensity) was measured. Red arrows point to the injection site on each animal. B) The pseudo-color image of the luminescence was overlaid on the photograph. C) Regions of interest (ROI) were selected (red circles) and the luminescence was quantified in each ROI. The data represent the net luminescence of infected ROI minus the ROI of mock infected. Aminophthalocyanine-Mediated Photodynamic Inactivation of Leishmania tropica | Antimicrobial Agents and Chemotherapy