Behavioral changes in mice caused by Toxoplasma gondii invasion of brain

Toxoplasma gondii, a protozoan parasite, is capable of infecting a broad range of intermediate warm-blooded hosts including humans. The parasite undergoes sexual reproduction resulting in genetic variability only in the intestine of the definitive host (a member of the cat family). The parasite seems to be capable of altering the natural behavior of the host to favor its transmission in the environment. The aim of this study was to evaluate the number of parasite cysts formed in the hippocampus and amygdala of experimentally infected mice as these regions are involved in defense behaviors control and emotion processing, and to assess the influence of the infection on mice behavior. The obtained results revealed the presence of parasite cysts both in the hippocampus and the amygdala of infected mice; however, no clear region-dependent distribution was observed. Furthermore, infected mice showed significantly diminished exploratory activity described by climbing and rearing, smaller preference for the central, more exposed part of the OF arena and engaged in less grooming behavior compared to uninfected controls

Vaccines against toxoplasma gondii : challenges and opportunities

Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge

Various aspects of IL-1 biological activity. 1. The role of IL-1 in parasitic infections

Interleukin–1 is one of the most potent proinflammatory cytokines involved in many physiologically important processes both beneficial and pathological. It appears in two different forms: IL-1 and IL-1b synthesized mainly by macrophages and monocytes. IL-1 remains inside the cells and is released during acute inflammatory diseases accompanied by cell lysis. IL-1b becomes biologically active after specific cleavage and is secreted to fulfill its multitude functions. This cytokine is involved in multiple gene up-regulation, higher expression of many cytokine receptors or induction of nitric oxide synthesis. Interleukin-1 is responsible for symptoms like fever or appetite loss during inflammatory diseases. It is capable of lymphocytes, macrophages or NK cells activation. This cytokine has a chemoattractant activity toward neutrophiles and monocytes and takes part in Th2 response development. Apart from other functions and activities, IL-1 is associated with many invasive illnesses such as parasitic infections. This cytokine influences the outcome of numerous parasitoses since it can limit parasite spread and survival within infected host by cooperation with other components of the immunological system and by the induction of anti-parasitic compounds. However, the proinflammatory activity of IL-1 may prove harmful in certain cases and may be responsible for parasite infection development

Various aspects of IL-1 biological activity. 1. The role of IL-1 in parasitic infections

Interleukin–1 is one of the most potent proinflammatory cytokines involved in many physiologically important processes both beneficial and pathological. It appears in two different forms: IL-1 and IL-1b synthesized mainly by macrophages and monocytes. IL-1 remains inside the cells and is released during acute inflammatory diseases accompanied by cell lysis. IL-1b becomes biologically active after specific cleavage and is secreted to fulfill its multitude functions. This cytokine is involved in multiple gene up-regulation, higher expression of many cytokine receptors or induction of nitric oxide synthesis. Interleukin-1 is responsible for symptoms like fever or appetite loss during inflammatory diseases. It is capable of lymphocytes, macrophages or NK cells activation. This cytokine has a chemoattractant activity toward neutrophiles and monocytes and takes part in Th2 response development. Apart from other functions and activities, IL-1 is associated with many invasive illnesses such as parasitic infections. This cytokine influences the outcome of numerous parasitoses since it can limit parasite spread and survival within infected host by cooperation with other components of the immunological system and by the induction of anti-parasitic compounds. However, the proinflammatory activity of IL-1 may prove harmful in certain cases and may be responsible for parasite infection development

Exosomes in the context of Toxoplasma gondii - host communication

Extracellular vesicles – EV’s, including exosomes, are known to be essential tools of intercellular communication, enabling the exchange of information without direct contact between cells. Exosomes are secreted both in vitro and in vivo by single- and multi-cellular organisms, regardless of their type, and play an essential role in cellto- cell communication. EV’s may carry various materials and ongoing studies have provided a new insight into their potential participation in various critical biological processes, including carcinogenesis, protein trafficking, immunostimulation and pathogenesis of infectious diseases. Although knowledge of the contribution of exosomes in Toxoplasma invasion is still very limited, the present article discusses aspects of their involvement in the interactions between host and T. gondii

Specific anti-Toxoplasma gondii antibodies produced in inbred mice differring in their natural resistance to toxoplasmosis

The laboratory diagnostics of T. gondii infections both in humans and animals relies mainly upon detection of specific antibodies. We studied the influence of the host genetic factors on the level and repertoire of antibodies produced in Toxoplasma infection employing as an experimental model two inbred mouse strains with different innate susceptibility to toxoplasmosis. Using polyvalent antigen preparations in ELISA and microagglutination we found no differences in the antibody levels in both strains. By comparison of the antibody profiles in immunoblot we determined mouse strain-specific and common toxoplasmosis markers

Specific anti-Toxoplasma gondii antibodies produced in inbred mice differring in their natural resistance to toxoplasmosis

The laboratory diagnostics of T. gondii infections both in humans and animals relies mainly upon detection of specific antibodies. We studied the influence of the host genetic factors on the level and repertoire of antibodies produced in Toxoplasma infection employing as an experimental model two inbred mouse strains with different innate susceptibility to toxoplasmosis. Using polyvalent antigen preparations in ELISA and microagglutination we found no differences in the antibody levels in both strains. By comparison of the antibody profiles in immunoblot we determined mouse strain-specific and common toxoplasmosis markers

The vaccines against toxoplasmosis - current status of the studies

The article presents current studies on the development of effective vaccines against toxoplasmosis — new approaches and strategies to construct prophylactic and therapeutic vaccines using recombinant microorganisms expressing protective T. gondii antigens, parasite DNA or RNA and recombinant antigens

Modeling of net ecosystem exchange (nee) at wetlands applying remote sensing

W artykule przedstawiono wyniki badań nad modelowaniem wymiany netto ekosystemu (NEE – ang. Net Ecosystem Exchange) bagiennego na przykładzie doliny Biebrzy z wykorzystaniem zdjęć satelitarnych i danych z pomiarów naziemnych z lat 2011–2015. Przeprowadzono szczegółową analizę zastosowania zdjęć optycznych i radarowych do uzyskania charakterystyk roślinno-wilgotnościowych wpływających na wymianę węgla. W wyniku przeprowadzonych analiz opracowano modele szacowania NEE, w których zastosowano opracowane na podstawie danych satelitarnych następujące parametry: wilgotność gleby (WG), zawartość wody w roślinach (WR). Do analizy WG i WR został zastosowany współczynnik wstecznego rozpraszania (σº) obliczony z sygnału zarejestrowanego w zakresie mikrofalowym przez urządzenia SAR (ang. Synthetic Aperture Radar) dla różnych polaryzacji fal. Prace badawcze zmierzające do określenia wielkości wymiany węgla oraz jego zróżnicowania przestrzennego i czasowego, przeprowadzone z uwzględnieniem informacji o pokrywie roślinnej i wilgotności gleby uzyskanych z danych satelitarnych, są ważne dla monitorowania ekosystemów bagiennych.The article presents results of the study on modeling Net Ecosystem Exchange (NEE) in the wetland ecosystem using remote sensing and in-situ data. The study has been conducted in Biebrza Valley for the years 2011–2015. The analysis of application of optical and microwave images for the assessment of vegetation-moisture conditions influenced carbon exchange has been performed. The impact of soil moisture and type of vegetation habitat on CO2 flux in wetland ecosystems has been analyzed to develop NEE models. Soil moisture (WG) and vegetation water content (WR) have been correlated with backscattering coefficient (σº) calculated from the signal registered by microwave satellites in different wave polarization. The research was focused on the assessment of carbon balance in time and space taking into account vegetation cover and soil moisture derived from satellite data. The research is important for monitoring wetland ecosystem