scholarly journals Four-dimensional characterization of the Babesia divergens asexual life cycle: from the trophozoite to the multiparasite stage

2020 ◽  
Author(s):  
José Javier Conesa ◽  
Elena Sevilla ◽  
María C. Terrón ◽  
Luis Miguel González ◽  
Jeremy Gray ◽  
...  
Keyword(s):  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Animal Health ◽  
Binary Fission ◽  
Main Stage ◽  
Babesia Divergens ◽  
Multiplication Cycle ◽  
Complex Population ◽  
Vertebrate Hosts

ABSTRACTBabesia is an apicomplexan parasite of significance that causes the disease known as babesiosis in domestic and wild animals and in humans worldwide. Babesia infects vertebrate hosts and reproduces asexually by a form of binary fission within erythrocytes/red blood cells (RBCs), yielding a complex pleomorphic population of intraerythrocytic parasites. Seven of them, clearly visible in human RBCs infected with Babesia divergens, are considered the main forms and named single, double and quadruple trophozoites, paired and double paired-pyriforms, tetrad or Maltese Cross, and multiparasite stage. However, these main intraerythrocytic forms coexist with RBCs infected with transient parasite combinations of unclear origin and development. In fact, little is understood about how Babesia builds this complex population during its asexual life cycle. By combining the emerging technique cryo soft X-ray tomography and video microscopy, main and transitory parasites were characterized in a native whole cellular context and at nanometric resolution. As a result, the architecture and kinetic of the parasite population has been elucidated. Importantly, the process of multiplication by binary fission, involving budding, was visualized in live parasites for the first time, revealing that fundamental changes in cell shape and continuous rounds of multiplication occur as the parasites go through their asexual multiplication cycle. Based on these observations, a four-dimensional (4D) asexual life cycle model has been designed highlighting the origin of the tetrad, double paired-pyriform and multiparasite stages and the transient morphological forms that, surprisingly, intersperse in a chronological order between one main stage and the next along the cycle.IMPORTANCEBabesiosis is a disease caused by intraerythrocytic Babesia parasites, which possess many clinical features that are similar to those of malaria. This worldwide disease, is increasing in frequency and geographical range, and has a significant impact on human and animal health. Babesia divergens is one of the species responsible for human and cattle babesiosis causing death unless treated promptly. When B. divergens infects its vertebrate hosts it reproduces asexually within red blood cells. During its asexual life cycle, B. divergens builds a population of numerous intraerythrocytic (IE) parasites of difficult interpretation. This complex population is largely unexplored, and we have therefore combined three and four dimensional (3D and 4D) imaging techniques to elucidate the origin, architecture, and kinetic of IE parasites. Unveil the nature of these parasites have provided a vision of the B. divergens asexual cycle in unprecedented detail and a key step to develop control strategies against babesiosis

scholarly journals Four-Dimensional Characterization of the Babesia divergens Asexual Life Cycle, from the Trophozoite to the Multiparasite Stage

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
José Javier Conesa ◽  
Elena Sevilla ◽  
María Carmen Terrón ◽  
Luis Miguel González ◽  
Jeremy Gray ◽  
...  
Keyword(s):  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Binary Fission ◽  
Life Cycle Model ◽  
Cycle Model ◽  
Babesia Divergens ◽  
Complex Population ◽  
Vertebrate Hosts ◽  
Kinetics Of

ABSTRACT Babesia is an apicomplexan parasite of significance that causes the disease known as babesiosis in domestic and wild animals and in humans worldwide. Babesia infects vertebrate hosts and reproduces asexually by a form of binary fission within erythrocytes/red blood cells (RBCs), yielding a complex pleomorphic population of intraerythrocytic parasites. Seven of them, clearly visible in human RBCs infected with Babesia divergens, are considered the main forms and named single, double, and quadruple trophozoites, paired and double paired pyriforms, tetrad or Maltese Cross, and multiparasite stage. However, these main intraerythrocytic forms coexist with RBCs infected with transient parasite combinations of unclear origin and development. In fact, little is understood about how Babesia builds this complex population during its asexual life cycle. By combining cryo-soft X-ray tomography and video microscopy, main and transitory parasites were characterized in a native whole cellular context and at nanometric resolution. The architecture and kinetics of the parasite population was observed in detail and provide additional data to the previous B. divergens asexual life cycle model that was built on light microscopy. Importantly, the process of multiplication by binary fission, involving budding, was visualized in live parasites for the first time, revealing that fundamental changes in cell shape and continuous rounds of multiplication occur as the parasites go through their asexual multiplication cycle. A four-dimensional asexual life cycle model was built highlighting the origin of several transient morphological forms that, surprisingly, intersperse in a chronological order between one main stage and the next in the cycle. IMPORTANCE Babesiosis is a disease caused by intraerythrocytic Babesia parasites, which possess many clinical features that are similar to those of malaria. This worldwide disease is increasing in frequency and geographical range and has a significant impact on human and animal health. Babesia divergens is one of the species responsible for human and cattle babesiosis causing death unless treated promptly. When B. divergens infects its vertebrate hosts, it reproduces asexually within red blood cells. During its asexual life cycle, B. divergens builds a population of numerous intraerythrocytic (IE) parasites of difficult interpretation. This complex population is largely unexplored, and we have therefore combined three- and four-dimensional imaging techniques to elucidate the origin, architecture, and kinetics of IE parasites. Unveiling the nature of these parasites has provided a vision of the B. divergens asexual cycle in unprecedented detail and is a key step to develop control strategies against babesiosis.

scholarly journals The Role of Cell Adhesion in the Malaria Life Cycle: From Gliding Sporozoites to Rolling Adhesion of Infected Red Blood Cells

2017 ◽  
Vol 112 (3) ◽  
pp. 330a
Author(s):  
Ulrich S. Schwarz ◽  
Friedrich Frischknecht ◽  
Michael Lanzer ◽  
Anna Battista ◽  
Christine Lansche ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells

scholarly journals Inside Scoop on Outside Proteins

2013 ◽  
Vol 82 (3) ◽  
pp. 921-923
Author(s):  
Jeffrey D. Dvorin
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Current Issue ◽  
Detailed Examination ◽  
Content Type ◽  
Human Malaria ◽  
Essential Step

ABSTRACTInvasion into red blood cells is an essential step in the life cycle of parasites that cause human malaria. Antibodies targeting the key parasite proteins in this process are important for developing a protective immune response. In the current issue, Boyle and colleagues provide a detailed examination ofPlasmodium falciparuminvasion and specifically illuminate the fate of surface-exposed parasite proteins during and immediately after invasion.

Update on malaria in Southern Africa.

2021 ◽  
Vol 7 (1) ◽  
pp. 01-01
Author(s):  
H.D. Solomons
Keyword(s):  
Life Cycle ◽  
Red Blood Cells ◽  
Southern Africa ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Red Cells ◽  
Anopheles Mosquito ◽  
Disease Spread ◽  
Human Host

Malaria is a eukaryotic plasmodium disease spread by the female Anopheles mosquito. Typically the malaria parasites invade the red blood cells. This results in fever, headache and can result in coma leading to death. Falciparum is the dangerous form of malaria leading to the most fatalities. Clasisically the red cells show ring forms and banana shaped gametocytes are seen in the peripheral blood. Fundamental to the understanding of malaria is an understanding of the life cycle of the malaria parasite in the mosquito and the human host and the sexual and asexual forms of the parasite.

The adaptation of three isolates ofBabesia divergensto continuous culture in rat erythrocytes

Parasitology ◽  
1991 ◽  
Vol 103 (2) ◽  
pp. 165-170 ◽  
Author(s):  
N. Ben Musa ◽  
R. S. Phillips
Keyword(s):  
Red Blood Cells ◽  
Continuous Culture ◽  
Blood Cells ◽  
Calf Serum ◽  
The Other ◽  
Foetal Calf Serum ◽  
Rat Erythrocytes ◽  
Rpmi Medium ◽  
Babesia Divergens ◽  
High Parasitaemias

Three isolates ofBabesia divergenshave been cultured continuously for 6 months in rat erythrocytes using the candle jar technique (Trager & Jensen, 1976). One isolate was already rat-adapted, the other two became adapted to rats through continuous culture in rat erythrocytes. Parasites were cultured in rat erythrocytes in RPMI medium supplemented with 20% foetal calf serum. The highest parasitaemia obtained was 35% and multiparasitization of red blood cells was often observed. Cultures ofB. divergensremained infective to splenectomized rats. Cultures with high parasitaemias contained a large number of extracellular merozoites. When separated from the red blood cells, these extracellular merozoites retained their infectivity.

scholarly journals Blood-feeding in the young adult filarial wormsLitomosoides sigmodontis

Parasitology ◽  
2004 ◽  
Vol 130 (4) ◽  
pp. 421-428 ◽  
Author(s):  
T. ATTOUT ◽  
S. BABAYAN ◽  
A. HOERAUF ◽  
D. W. TAYLOR ◽  
W. J. KOZEK ◽  
...  
Keyword(s):  
Life Cycle ◽  
Young Adult ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Feeding ◽  
Post Inoculation ◽  
Mongolian Gerbils ◽  
Litomosoides Sigmodontis ◽  
Precise Moment ◽  
Kinetics Of

In this study with the filarial modelLitomosoides sigmodontis, we demonstrate that the worms ingest host red blood cells at a precise moment of their life-cycle, immediately after the fourth moult. The red blood cells (RBC) were identified microscopically in live worms immobilized in PBS at 4 °C, and their density assessed. Two hosts were used: Mongolian gerbils, where microfilaraemia is high, and susceptible BALB/c mice with lower microfilaraemia. Gerbils were studied at 12 time-points, between day 9 post-inoculation (the worms were young 4th stage larvae) and day 330 p.i. (worms were old adults). Only the very young adult filarial worms had red blood cells in their gut. Haematophagy was observed between days 25 and 56 p.i. and peaked between day 28 and day 30 p.i. in female worms. In males, haematophagy was less frequent and intense. Similar kinetics of haematophagy were found in BALB/c mice, but frequency and intensity tended to be lower. Haematophagy seems useful to optimize adult maturation. These observations suggest that haematophagy is an important step in the life-cycle ofL. sigmodontis. This hitherto undescribed phenomenon might be characteristic of other filarial species including human parasites.

Freeze-etch studies on the gametocytes of Plasmodium falciparum

1983 ◽  
Vol 41 ◽  
pp. 566-567
Author(s):  
Charles A.M. Meszoely ◽  
Eric F. Erbe ◽  
Russell L. Steere ◽  
Timothy Palmer ◽  
Richard L. Beaudoin
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Freeze Fracture ◽  
Malarial Parasite ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Food Vacuoles ◽  
Ultrathin Sections

The Erythrocytic stages of the Honduras strain of the malarial parasite Plasmodium falciparum were maintained in tissue culture medium RPMI 1640. Red blood cells containing gametocytes and other erythrocytic stages were fixed in 2% glutaraldehyde, and cryoprotected in 30% glycerol in H2O. This preparation was freeze-etched for one minute at -98°C in a modified Denton DFE-2 freeze-etch module. Stereo pairs with specimen tilt of 10 between electron micrographs were obtained with a JEM-100B transmission electron microscope equipped with a 60° top entry goniometer stage.The fine structure of the gametocytes of malarial parasites has been studied by conventional electron microscopic methods [stained ultrathin sections (2 and 3)], but this stage of the life cycle has not been demonstated previously with freeze-fracture studies.Since the red blood cells in our preparation also contained other stages of the life cycle, the following combination of characteristics were used to differentiate the gametocytes: presence of microtubules; food vacuoles; and large size.Microtubules are not found in trophozoites, and merozoites are relatively small and do not contain food vacuoles.

Eperythrozoon suis in Naturally Infected Pigs: A Light and Electron Microscopic Study

1982 ◽  
Vol 19 (6) ◽  
pp. 651-657 ◽  
Author(s):  
A. Pospischil ◽  
R. Hoffmann
Keyword(s):  
Lymph Nodes ◽  
Red Blood Cells ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Blood Cells ◽  
Close Contact ◽  
Binary Fission ◽  
Electron Microscopic ◽  
Nuclear Structures ◽  
Spleen And Lymph Nodes

The light and electron microscopic characteristics of natural infections with Eperythrozoon suis are reported. E. suis are enclosed by a single membrane, and they reach a length of up to 600 nm and a diameter of 375 to 500 nm. Neither distinct organelles nor nuclear structures appear in the parasites cytoplasm. They replicate by binary fission, and have close contact with red blood cells without showing any signs of membrane alteration. Massive phagocytosis of whole red blood cells not parasitized by E. suis occurs in spleen and lymph nodes.

Modulation of the anti-phosphorylcholine immune response duringTrichinella spiralisinfections in mice

Parasitology ◽  
1987 ◽  
Vol 95 (3) ◽  
pp. 583-592 ◽  
Author(s):  
F. M. Ubeira ◽  
J. Leiro ◽  
M. T. Santamarina ◽  
M. L. Sanmartin-Duran
Keyword(s):  
Immune Response ◽  
Life Cycle ◽  
Antibody Response ◽  
Red Blood Cells ◽  
Post Infection ◽  
Blood Cells ◽  
Trichinella Spiralis ◽  
Heterologous Antigen ◽  
Specific Suppression ◽  
Antigenic Fraction

SUMMARYThe nematodeTrichinella spiralisis able to modulate the antibody response, as measured by the plaque-forming cell (PFC) technique, to three thymus-dependent (TD) antigens: (1) a heterologous antigen unrelated to the parasite (sheep red blood cells (SRBC)); (2) an antigenic fraction, rich in phosphorylcholine (PC), obtained fromT. spiralis(FCpl) and (3) a heterologous antigen unrelated to the parasite, but sharing the PC epitope with the FCpl fraction (PC-KLH). During the life-cycle of the parasite in BCF1 mice, two opposing immunomodulating activities occur: (1) an immuno-potentiating activity in mice infected during the intestinal and larval migratory stages, for all three antigens, and (2) a carrier-specific immunosuppressive response in mice infected and immunized with the FCpl fraction during the muscle phase of the life-cycle. The anti-PC PFC response of these mice is dependent on the infection dose and decreases from day 35 post-infection (p.i.) until at least day 85 p.i.. The factor responsible for the stimulating effect observed during this stage is the presence of migratory larvae in the host. All the foregoing seems to indicate thatT. spiraliscan use specific suppression mechanisms to aid in its own survival.

Sign in / Sign up

Export Citation Format

Share Document