scholarly journals In Astrocytes the Accumulation of the Immunity-Related GTPases Irga6 and Irgb6 at the Vacuole ofToxoplasma gondiiIs Dependent on the Parasite Virulence

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Felix P. Lubitz ◽  
Daniel Degrandi ◽  
Klaus Pfeffer ◽  
Anne K. Mausberg
Keyword(s):  
Protozoan Parasite ◽  
Obligate Intracellular ◽  
Virulent Strains ◽  
Resistance System ◽  
A Cell ◽  
The Central Nervous System ◽  
Low Levels ◽  
The Individual ◽  
Common Infection ◽  
Intracellular Protozoan Parasite

Toxoplasma gondiiis an obligate intracellular protozoan parasite responsible for a common infection of the central nervous system. Interferon (IFN)γis the key cytokine of host defence againstT. gondii. However,T. gondiistrains differ in virulence andT. gondiifactors determining virulence are still poorly understood. In astrocytes IFNγprimarily induces immunity-related GTPases (IRGs), providing a cell-autonomous resistance system. Here, we demonstrate that astrocytes prestimulated with IFNγinhibit the proliferation of various avirulent, but not virulent,T. gondiistrains. The two analyzed immunity-related GTPases Irga6 and Irgb6 accumulate at the PV only of avirulentT. gondiistrains, whereas in virulent strains this accumulation is only detectable at very low levels. Both IRG proteins could temporarily be found at the same PV, but did only partially colocalize. Coinfection of avirulent and virulent parasites confirmed that the accumulation of the two analyzed IRGs was a characteristic of the individual PV and not determined by the presence of other strains ofT. gondiiin the same host cell. Thus, in astrocytes the accumulation of Irga6 and Irgb6 significantly differs between avirulent and virulentT. gondiistrains correlating with the toxoplasmacidal properties suggesting a role for this process in parasite virulence.

scholarly journals Investigation of Toxoplasma gondii Infection in Aborted Fetuses of Sheep Using PCR: A Study in North Khorasan Province, Iran

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Mitra Salehi ◽  
Hosein Nezami ◽  
Hamid Reza Niazkar
Keyword(s):  
Toxoplasma Gondii ◽  
Gestational Age ◽  
Protozoan Parasite ◽  
Abortion Rate ◽  
Obligate Intracellular ◽  
Significant Difference ◽  
Pcr Method ◽  
Toxoplasma Gondii Infection ◽  
Intracellular Protozoan Parasite

Toxoplasma gondii is a zoonotic obligate intracellular protozoan parasite that infects warm-blooded animals as well as humans worldwide. The purpose of this study was to delineate the prevalence of Toxoplasma infection in aborted fetuses of sheep in North Khorasan province, Iran. Three hundred and ninety-nine samples of the liver (133 samples), placenta (133 samples), and brain (133 samples) from 133 aborted fetuses of sheep were collected from 2015 to 2017. The ages of aborted fetuses were higher than 120 days’ gestational age in this study. According to the samples, sixteen out of 133 aborted fetuses of sheep were infected with T. gondii. Toxoplasma DNA was found in the placenta (68.75%) and liver (31.25%) samples of infected fetuses using the PCR method. The highest and lowest rates of Toxoplasma infection were observed during 2016 and 2017, respectively. Shirvan and Faruj provinces were recognized as the two most infected districts among others. There was a significant difference between the year and abortion rate in sheep due to infection by the Toxoplasma parasite (P<0.05). Furthermore, no significant difference between the prevalence of T. gondii infection and aborted fetuses was seen (P>0.05) in different areas. According to the present study, T. gondii infection can be one of the causes of fetus abortion of sheep in North Khorasan province, Iran.

Seroprevalance of Canine Brucellosis and Toxoplasmosis in Female and Male Dogs and Relationship to Various Factors as Parity, Abortion and Pyometra

2017 ◽  
Author(s):  
Osman Ergene ◽  
Bekir Celebi ◽  
Ibrahim Kucukaslan
Keyword(s):  
Toxoplasma Gondii ◽  
Reproductive Tract ◽  
Protozoan Parasite ◽  
Reproductive Parameters ◽  
Obligate Intracellular ◽  
North Cyprus ◽  
Brucella Canis ◽  
Late Abortion ◽  
Canine Brucellosis ◽  
Intracellular Protozoan Parasite

The objective of this study was to determine the seroprevalance of canine brucellosis and toxoplasmosis in female and male dogs and also determine the realtionship to various factors as parity, abortion and pyometra. Brucella canis is a disease of the reproductive tract that may cause late abortion, infertility and fail of conception with optimum insemination time in females and infection of the sexual organs in males. Toxoplasma gondii is an important obligate intracellular protozoan parasite which can affect all warm-blooded mammals and humans which may cause fatal diseases with severe problems, such as abortion. As a result, in this study B. canis was determined in low seroprevalence in some cases on the island (North Cyprus), T. gondii was determined as an important contagious parasite. Also reproductive parameters like parity, spaying, cyclicity could be important too and it was presented that extended evaluation of these factors is needed with further studies.

scholarly journals The major 85-kD surface antigen of the mammalian form of Trypanosoma cruzi is encoded by a large heterogeneous family of simultaneously expressed genes.

1990 ◽  
Vol 172 (2) ◽  
pp. 589-597 ◽  
Author(s):  
S Kahn ◽  
W C Van Voorhis ◽  
H Eisen
Keyword(s):  
Trypanosoma Cruzi ◽  
Gene Family ◽  
Protozoan Parasite ◽  
Surface Antigens ◽  
African Trypanosomes ◽  
Antigenic Diversity ◽  
Obligate Intracellular ◽  
The Family ◽  
Large Repertoire ◽  
Intracellular Protozoan Parasite

Trypanosoma cruzi is an obligate intracellular protozoan parasite. The parasite mammalian stage surface antigens exhibit extensive antigenic diversity. We have characterized a family of T. cruzi genes that code for a polymorphic set of 85-kD surface antigens, the SA85-1 antigens. The family contains greater than 100 genes and pseudogenes, of which a minimum of nine are transcribed. The gene family is expressed in the mammalian stage only. A subset of the gene family is present in two telomere-linked copies in the genome. Telomere linkage of other expressed SA85-1 genes has not been demonstrated. We have shown that at least three members of the SA85-1 gene family encode antigens at the surface of the mammalian stage of the parasite. Interestingly, these three antigens are expressed on all the trypanosomes examined. This suggests that T. cruzi simultaneously expresses a large repertoire of similar, but diverse antigens at its surface. Thus, T. cruzi exhibits extensive antigenic diversity in a system unique from that of African trypanosomes, perhaps reflecting its intracellular niche.

scholarly journals XXVII.—On the Restoration of Co-ordinated Movements after Nerve Section

1900 ◽  
Vol 39 (3) ◽  
pp. 685-702 ◽  
Author(s):  
Robert Kennedy
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Point Of View ◽  
The Other ◽  
Nerve Fibres ◽  
Spinal Root ◽  
A Cell ◽  
The Central Nervous System ◽  
The One ◽  
The Individual

From the point of view of its function, a nerve fibre is a conductor of nervous impulses, and as such is the path of communication between two structures, the one situated in the central nervous system, and the other in the periphery. In the mixed nerve, such as the sciatic, the nerve fibres are distinguished as afferent or as efferent, according as they conduct impulses originating at the periphery, and received by a cell in the central nervous system, or vice versâ. It has long since been shown that nerve fibres are capable of conducting impulses in either direction, but normally, from their anatomical connections, the individual nerve fibres are conductors for impulses only in the one or in the other direction. This is proved by the Wallerian method of investigation, as on severance of the posterior spinal root distal to the ganglion only certain fibres degenerate and the conductivity of the nerve only for afferent impulses is lost, while the severance of the anterior root is followed by the degeneration of the remainder with loss of functions depending on efferent impulses.

ROLES OF IFN-γ ON STAGE CONVERSION OF AN OBLIGATE INTRACELLULAR PROTOZOAN PARASITE, Toxoplasma Gondii

2002 ◽  
Vol 21 (4-5) ◽  
pp. 405-421 ◽  
Author(s):  
AKIHIKO YANO ◽  
HYE-SEONG MUN ◽  
MEI CHIN ◽  
KAZUMI NOROSE ◽  
KAZUYUKI HATA ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Protozoan Parasite ◽  
Obligate Intracellular ◽  
Stage Conversion ◽  
Ifn Γ ◽  
Intracellular Protozoan Parasite

scholarly journals Babesia divergens: A Drive to Survive

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 95 ◽  
Author(s):  
Cheryl A Lobo ◽  
Jeny R Cursino-Santos ◽  
Manpreet Singh ◽  
Marilis Rodriguez
Keyword(s):  
Protozoan Parasite ◽  
Blood Stream ◽  
Survival Strategies ◽  
Optimum Conditions ◽  
Obligate Intracellular ◽  
Diverse Species ◽  
Babesia Divergens ◽  
Host Blood ◽  
Intracellular Protozoan Parasite

Babesia divergens is an obligate intracellular protozoan parasite that causes zoonotic disease. Central to its pathogenesis is the ability of the parasite to invade host red blood cells of diverse species, and, once in the host blood stream, to manipulate the composition of its population to allow it to endure unfavorable conditions. Here we will review key in vitro studies relating to the survival strategies that B. divergens adopts during its intraerythrocytic development to persist and how proliferation is restored in the parasite population once optimum conditions return.

scholarly journals ToxoplasmaRhoptries: Unique Secretory Organelles and Source of Promising Vaccine Proteins for Immunoprevention of Toxoplasmosis

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Henryka Dlugonska
Keyword(s):  
Neospora Caninum ◽  
Parasitophorous Vacuole ◽  
Protozoan Parasite ◽  
Current Data ◽  
Intracellular Killing ◽  
Apicomplexan Parasites ◽  
Obligate Intracellular ◽  
Animal Pathogens ◽  
Intracellular Protozoan Parasite

Toxoplasma gondiiis an obligate intracellular protozoan parasite classified in the phylum Apicomplexa, which includes numerous notable human and animal pathogens (Plasmodiumspecies,Cryptosporidiumspecies,Neospora caninum, etc.). The invasive stages of apicomplexans are characterized by the presence of an apical complex composed of specialized cytoskeletal and secretory organelles, including rhoptries. Rhoptries, unique apical secretory organelles shared exclusively by all apicomplexan parasites, are known to be involved in an active parasite's penetration into the host cell associated with the biogenesis of specific intracellular compartment, parasitophorous vacuole in which the parasite multiplies intensively, avoiding intracellular killing. Due to the key biological role of rhoptries, rhoptry proteins have recently become vaccine candidates for the prevention of several parasitoses, toxoplasmosis among them. The article presents current data onT. gondiirhoptries biology and new approaches to the development of effective vaccines against toxoplasmosis using rhoptry antigens.

scholarly journals Unexpectedly low seroprevalence of toxoplasmosis in South Africa

2012 ◽  
Vol 79 (2) ◽  
Author(s):  
K. Kistiah ◽  
John Frean ◽  
J. Winiecka-Krusnell ◽  
A. Barragan
Keyword(s):  
South Africa ◽  
Protozoan Parasite ◽  
Hiv And Aids ◽  
Sub Saharan Africa ◽  
People Living With Hiv ◽  
The Central Nervous System ◽  
Sub Saharan ◽  
Living With Hiv ◽  
The Impact ◽  
Intracellular Protozoan Parasite

Toxoplasmosis is an infection of warm-blooded vertebrates caused by the obligate intracellular protozoan parasite, Toxoplasma gondii. It is one of the most common parasitic diseases of humans, infecting approximately one-third of the world’s population. In persons with advanced HIV, toxoplasmosis represents a major opportunistic infection of the central nervous system. Approximately two-thirds of all people living with HIV live in sub-Saharan Africa. In areas such as this, toxoplasmosis could theoretically pose a huge threat. There is little known about T. gondii prevalence in humans in Africa. Geographically, prevalences vary widely on this continent, as observed in other parts of the world. There is limited historical information about the disease in South Africa. More knowledge is needed at a regional level about the risk of toxoplasmosis, diagnostic issues, and measures to reduce the risk to susceptible persons. The seroprevalence of T. gondii in selected populations, namely HIV-positive and HIV-negative individuals, and a more general sample biased towards pregnant women, was therefore investigated and found to be 9.8% (37/376), 12.8% (48/376) and 6.4% (32/497) respectively. Compared with historical data from South Africa, the prevalence has decreased substantially; however, the incidence of clinical disease is unknown, despite the very high burden of HIV and AIDS cases (5.9 million and 0.7 million, respectively in 2009). This study provided information relating to the diagnosis and current seroprevalence of T. gondii in South Africa. Many questions still remain to be answered however, to fully understand the impact of this parasite on the country’s population.

scholarly journals Significance of Neospora caninum in cattle farming

2006 ◽  
Vol 60 (3-4) ◽  
pp. 223-231
Author(s):  
Tamara Ilic ◽  
Sanda Dimitrijevic
Keyword(s):  
Neospora Caninum ◽  
Protozoan Parasite ◽  
The United States ◽  
Neonatal Deaths ◽  
Obligate Intracellular ◽  
The World ◽  
Three Stages ◽  
Almost All ◽  
Cycle Covers ◽  
Intracellular Protozoan Parasite

Neospora caninum is an obligate intracellular protozoan parasite which primarily causes diseases in dogs and cattle all over the world. It was first described in Norway in the mid-eighties in dogs, after which, until the present time, clinical neosporosis was proven in sheep, goats, deer, rhinoceroses, horses, and experimental rodents. Antibodies against N. caninum have been found also in the serum of water buffalo, red and gray foxes, coyotes, camels, and felines. Due to the similarity of this Coccidia with Toxoplasma gondi, the neosporosis was for a series of years incorrectly diagnozed as toxoplasmosis. Domestic canines, dogs, are the only real host for N. caninum. Its life cycle covers three stages of development: tachyzoites, tissue cysts and oocysts. Carnivores are infected by ingesting parts of infected tissue which contain tissue cysts with bradyzoites. The dominant pathway of transmission of this cause in cattle is transplacentary infection, but cattle can also be infected by ingestion of feed or water contaminated by sporulated oo-cysts of N. caninum. Bitches can be subclinical carriers of the parasite, when they pass on the cause transplacentarily, which results in more than one litter being born with the infection. Neosporosis today appears as the main cause of abortions and neonatal deaths in dairy cows and fattening cattle in almost all parts of the world, but with the highest incidence in the United States (US), New Zealand, The Netherlands, and Germany. The treatment of this disease has not been fully determined, but medicines used for the treatment of toxoplasmosis have yielded certain good results. There is no verified vaccine that would prevent undesired abortions in cattle. .

scholarly journals Initial phospholipid-dependent Irgb6 targeting to Toxoplasma gondii vacuoles mediates host defense

2019 ◽  
Vol 3 (1) ◽  
pp. e201900549 ◽  
Author(s):  
Youngae Lee ◽  
Hiroshi Yamada ◽  
Ariel Pradipta ◽  
Ji Su Ma ◽  
Masaaki Okamoto ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Parasitophorous Vacuole ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Interferon Response ◽  
Obligate Intracellular ◽  
Membrane Bound ◽  
Ifn Γ ◽  
Intracellular Protozoan Parasite

Toxoplasma gondii is an obligate intracellular protozoan parasite capable of infecting warm-blooded animals by ingestion. The organism enters host cells and resides in the cytoplasm in a membrane-bound parasitophorous vacuole (PV). Inducing an interferon response enables IFN-γ–inducible immunity-related GTPase (IRG protein) to accumulate on the PV and to restrict parasite growth. However, little is known about the mechanisms by which IRG proteins recognize and destroy T. gondii PV. We characterized the role of IRG protein Irgb6 in the cell-autonomous response against T. gondii, which involves vacuole ubiquitination and breakdown. We show that Irgb6 is capable of binding a specific phospholipid on the PV membrane. Furthermore, the absence of Irgb6 causes reduced targeting of other effector IRG proteins to the PV. This suggests that Irgb6 has a role as a pioneer in the process by which multiple IRG proteins access the PV. Irgb6-deficient mice are highly susceptible to infection by a strain of T. gondii avirulent in wild-type mice.

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