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Využívání dlouhodobého uvolňování léčiv v reprodukci ryb
KNOWLES, Jindřiška
The PhD thesis was aimed to develop and validate an innovative method of hormone stimulation using PLGA microparticles for sustained release of a synthetic analogue of mammalian gonadotropin-releasing hormone in several economically important fish species. Since this is the first record of the use of PLGA microparticles in fish, the focus was to establish the optimal dose of the active substance, quantify the steroid response of the broodstock, and to assess the quality and quantity of obtained sex products. The theoretical part of the thesis was focused on elaborating a study reviewing methods of hormonal treatment in fish, and discuss the potential of PLGA microparticles in fish reproduction. While, the experimental part of the work was focused on evaluation of the effect of PLGA microparticles in those fish species commonly reared in intensive and pond aquaculture. Fish of both sexes were included to determine the effect of the treatment on the production and quality of eggs as well as on the quality and quantity of sperm.
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Interakce spermií a jiker u sladkovodních ryb: vliv prostředí na fertilizační proces
KHOLODNYY, Vitaliy
Fertilization of fresh water fish occurs in an environment which may affect negatively the gametes, therefore the fish male gametes should reach their counterpart, the female gamete, as soon as possible because spermatozoa become damaged within minutes or less due to osmotic shock. Existence of specific mechanism triggering, supporting and guiding the encounter of gametes would be highly expedient in these conditions. The eggs of many externally fertilizing freshwater fish species are released into the external milieu surrounded by a coat of ovarian fluid (OF) with a composition ideal for supporting and protecting eggs and sperm against the deleterious effect of freshwater. The existing data support the idea that the properties of OF and/or the specific compounds contained in it or released by the eggs could significantly affect the behavior of male gametes and consequently influence the outcome of fertilization in terms of the number of fertilized oocytes. The mechanisms which facilitate and trigger gametes' encounter are also highly demanded in terms of natural selection. It was found that presence of OF affected significantly the behavior of rainbow trout spermatozoa, in particular, their motility traits: higher velocity was supported for longer time and trajectories were straightened, comparing to those observed in water. In the microcapillary spermatozoon accumulation test (test of chemotactic response) the rainbow trout OF showed a trapping effect on activated male gametes which depended on osmotic properties of the activating media. Different molecular weight fractions from OF affected the tactic behavior of the cells in a various way. The most significant trapping effect was rendered by low molecular fraction and the possible chemotactic agent was found to be thermostable. The trapped cells showed specific turn-and-run behavior accompanied by asymmetric bending of flagella and burst-like increase of calcium concentration in the bended area. The in vitro fertilization test revealed the enhancement of spermatozoa performance, especially in the samples from the related individuals, which led to the higher embryo development rate. Presence of particular concentration of ovarian fluid (30% solution in water) had inhibiting effect on sterlet spermatozoa motility initiation. Lower concentrations of the ovarian fluid improved the longevity of spermatozoa and did not affect their trajectories. Test of chemotactic response showed no effect of ovarian fluid on spermatozoa behavior, while at the same time the attracting effect of egg conditioned medium was evident (i.e. due to some substances released from the eggs during their contact with fresh water). The results of in vitro fertilization test showed that presence of ovarian fluid prevented the eggs from losing the fertilizing ability due to the contact with water, as well as promoted the spermatozoa to fertilize the eggs during longer period of time. Presence of common carp ovarian fluid in the activation medium caused the decrease of the velocity of spermatozoa comparing to the OF-free medium and significantly altered the motility pattern from straightforward motility observed in the water to the tumbling in the medium with high OF content (50%). Introduction of OF (in the sperm accumulation test) entailed immediate and prominent chemotactic-like reaction of spermatozoa. The environmental conditions which accompany the encounter of gametes, in particular presence of OF, calcium ion content and osmolarity, significantly affect the performance of male gametes in spermatozoa in rainbow trout, sterlet and common carp in terms of changes in velocity, path linearity and ability to response to the external signals, e.g. attractants. The conducted study allowed to conclude that way how the ovarian fluid affects the behavior of spermatozoa in these species may be associated with their reproduction (spawning) strategy.
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The effect of oxidative stress on gametes and early embryos concerning assisted reproductive techniques in human
Kapsdorferová, Viktória ; Krylov, Vladimír (advisor) ; Frolíková, Michaela (referee)
One of the factors influencing the successful outcome of assisted reproduction could be the oxidative stress (OS), which is characterized by a disequilibrium between prooxidants and antioxidants in favour of prooxidants. Important prooxidants are both radical and non-radical reactive oxygen species (ROS) with a high reactivity and strong oxidizing effects on biological substrates. The origins of ROS and OS are assisted reproductive technologies (ART) and several exogenous sources to which gametes and early embryos are exposed during in vitro manipulation. The overproduction of ROS is associated with several negative effects on the cellular and molecular level. However, ROS are a common part of the cellular metabolism and important signaling molecules participating in processes necessary for the physiological development of gametes and early embryos. Hence, strategies to reduce OS may lead to improved results in assisted reproduction. The purpose of this bachelor's thesis is to provide a comprehensive review of literature focused on the identification of sources of ROS and OS, their effect on gametes and early embryos, as well as the possibilities for OS reduction and improvement of cultivation conditions in ART in human. Key words: oxidative stress, reactive oxygen species, gametes, early embryo,...
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Does the child born from donated gametes right to know its biological parents?
TOŠNEROVÁ, Jana
This thesis deals with the issue of assisted reproduction, ethical aspects of infertility treatment and in particular looking for the answer to the question of whether they have children from donated gametes natural right to know their biological parents, the gamete donors. The diploma thesis is devoted to the topic of infertility and description of some of the methods of assisted reproduction. Emphasis is on the status of child from gamete donation, especially with regard to its natural right to know the donor. Children only have the right to know the donor of the gametes from which it originated in countries, where the donation is not anonymous.. For these countries, the Czech republic does not belong. Seeking an answer to the question whether it is these children's natural right to know the identity of the donor, is started from how the natiral law is understood in general and also from a bio-psycho-social needs that children have. The work also includes a description of an exploratory survey realized in one of the reproductive clinics. Through survey, Infertile couples commented on the topic of organ donation and the possibility to confer children the natural right to know their biological parents.
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