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Pasozyty jako naturalny skladnik ekosystemu

100%
Parasites as a natural element of any ecosystem. The article presents some ideas upon the functioning of the parasite populations and communities in relation to the whole ecosystem. The author underlines that the parasites are one of the natural elements of every biocenosis and their existence submittes to similar ecological rules as the populations and communities of free-living organisms. Colonization of their particular environment (living organism) demands some adaptations allowing to resist immunological defense of the host, and to coexist with other parasite species harboured by the same host, not exploiting the supplies over the host "carying capacity", what could provoke the streng pathogenic eB'ects, including host death. The mechanims maintaning the state of relative stability in host-parasite system are similar as in the case of free-living organisms, and are of both parasite-and host origin. They can confine the number of parasites (elimination of some specimens) or their biomass (growth restraint), limit their fecundity (maturation resttaint), or make particular species to use different supply (niches separation). On the other hand parasite can regulate the demography of host population: restrict their fecundity, or kill their host directly or indirectly (making them an easier prey for predators). The author presents and discusses some examples illustrating the activity of the regulating mechanisms in host-parasite relationship, as well as the role of parasites in energetic ballance of ecosystem and in "engineering of ecosystem".
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Niektóre osobliwości ewolucji endopasożytów

72%
Evolution of parasite - host systems should be treated as a specific kind of co-evolution. Although its course is in accordance with the general rules of organic world evolution, it has some peculiarities. One of them is retardation or acceleration of endoparasites' phylogenesis, as compared with the hosts' one. The second one is different speed of phylogenetic changes of endoparasites belonging to the same systematic group. These changes can be significantly limited, as well. Phylogenetic changes of euglenids - intestine parasites of Copepoda - are considerably limited, even in comparison with the scale of changes of such species which begin their parasitic life by infecting Copepoda eggs.
In the course of experimental hymenolepidosis in rats, varying mobilization of mastocytes, dependent on the organ of their origin, was observed. The highest was in the small intestine, lower in the mesenterial lymph nodes and the spleen. Various degree of correlation between the mastocyte mobilization and the histopathological changes was stated.
A histochemical assay was elaborated to study lactate dehydrogenase activity in the tissues of Fasciola hepatica and in the liver of mice during the course of fasciolosis. LDH activity was determined in the tegument, muscles, parenchyma, oral sucker and the caecum of juvenile and adult liver flukes inhabiting the host liver parenchyma and bile ducts. The most substantial changes in LDH activity were recorded in the tegument outer surface layer. White mice of CFW strain were infected with 10, 30 and 50 doses of F. hepatica metacerkariae administered per os. A dramatic decrease in LDH activity in the experimental mice liver during the course of infection, particularly in the acute fasciolosis was observed.
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Pomiary wplywu pasozytow na kondycje ryb

58%
A brief description of the fish condition indices is provided together with proper formulae, and examples of their application in parasitological studies. Author argues that, since some indices react comparatively slowly upon parasite-induced stress, and some respond quite rapidly, a whole set of indices should be used in order to provide researchers with complete picture of fish-parasite interactions.
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