When two alleles carried by a heterozygote are transmitted unequally to the zygote at the time of fertilization, transmission ratio distortion occurs. The best studied example of this phenomenon in mammals is t-haplotype in mice. The mouse t-haplotype is a selfish variant region on chromosome 17, in nature transmitted as a unit. Male mice homozygous for t haplotype are sterile, but heterozygotes transmit the t haplotype up to 99% of their progeny. This is believed to be caused by motility differences between sperm carrying the t haplotype and wild-type sperm from the same heterozygous male. The concrete mechanism of the postulated sperm competition in favour of t haplotype carrying sperm was so far not fully illuminated. During this project, we worked with the hypothesis that the differences in sperm motility putatively responsible for transmission ratio distortion are triggered, at least in part, by metabolic causes. Our results from ATP and mitochondrial membrane potential (MMP) comparison indeed suggest that there are metabolic dissimilarities in sperm from the different genotypes of t (t/t, t/+, +/+). Specifically, our data show that there is significantly less ATP in t/t sperm when compared to the other two genotypes. Likewise, sperm from t/t mice also seem to have lower MMP, suggesting that...

The male gametes (sperms) are under strong sexual selection and are therefore very diverse in their morphology and often differ even amongst closely related species. Sperms are thus assumed to play very important role in reproductive isolation between species, due to their fast evolution in morphology. In my master thesis, I have studied the possible role of sperm morphology divergence in reproductive isolation in two sister species of passerine birds, the common nightingale (Luscinia megarhynchos) and the thrush nightingale (L. luscinia). The areas of these species overlap in secondary contact zone running across central and Eastern Europe, where they occasionally hybridize. I have compared sperm morphology of males of both species originating in allopatric and sympatric localities as well as interspecies hybrids. The results showed significant differences in total sperm length which is approximately 20 % longer in the common nightingale. That is caused by great interspecies divergence in midpiece (containing mitochondria) length. Interspecific hybrids showed sperms with intermediate length but despite expectations completely morphologically normal. This outcome corresponds with observed fertility in F1 hybrid males. What I consider to be an essential finding is a significant divergence in head...

The phenotype-linked fertility hypothesis predicts that both, male carotenoid-based sexual ornamentation and their spermatozoa are phenotypically plastic and may be co-affected by the environment. One of the factors affecting their phenotype may be oxidative stress and the ability of organism to eliminate its effect. Oxidative stress may reduce sperm quality because sperm lack the ability to repair DNA, but it can also affect spermatogenesis itself. However, some substances may function as antioxidants, and thus eliminate effect of reactive oxygen species (oxidative stress) in the body. In this study, adult zebra finch males (Taeniopygia guttata) originating from the domesticated and recently wild-derived populations were exposed to the diquat (D), which enhances the oxidative stress, and carotenoid lutein (L), which could have an antioxidant function. Experimental design had factorial character 2x2 with a control (group L, D, LD, control). Neither oxidative stress, carotenoids, nor their interactions affected sperm morphology or velocity and it also did not increase abnormal sperm proportion in the ejaculate. However, the differences were observed at the molecular level, where by inducing the oxidative stress, the sperm had reduced signal intensity of acetylated α-tubulin in the sperm tails....

Fertilization is a multiple step process leading to fusion of female and male gametes resulting in a formation of a zygote. Besides direct gamete interaction via binding receptors localized on both oocyte and sperm surface, fertilization also involves communication based on chemical molecules triggering various signalling pathways. This work is aimed to characterize chemical communication of gametes of a model organism Mus musculus. For this purpose, modern proteomic and visualisation methods like nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS), selected reaction monitoring (SRM) and immunofluorescent microscopy were used. Lipocalins were identified as candidate proteins involved in communication including those from major urinary proteins (MUPs), LCN lipocalins and fatty acid binding proteins (FABPs). For the first time, we report their presence in the sperm acrosome. Based on lipocalins capacity to bind and transport other molecules, we propose that these proteins have a protective and/or signalling role for gametes. Furthermore, chemical communication between sperm and oocyte is based on chemotaxis which enables their interaction before their fusion. In this work, we detected that spermatozoa show chemotactic responses in the presence of L-glutamate. This amino acid naturally...

Sperm-­-egg membrane interaction and fusion is mediated by various molecules of the different protein network that are located on both egg and sperm membrane. So far, many proteins have been selected to be fusion candidates, some of them (Izumo1, CD9, Juno) were proven to be essential, whereas others were discovered to play an unsuspected new active role (CD46, tetraspanins). After the adhesion of sperm to an egg, Juno located on the oolema associates with monomeric Izumo1 on sperm membrane, which is results in Izumo1 dimerization following quick removal of Juno from the egg surface as described in mouse. It implies that additional receptor on the egg membrane is required to play a role in sperm-­-egg fusion. To find a human fusogenic receptor for IZUMO1 protein we used one-­-bead-­-one-­-compound (OBOC) assay, a random screening approach. A bead, fulfilling all the requirements when interacting with the human sperm, carried a peptide sequence showing homology with the conserved Ig domain of the human specific Fc receptor-­-like protein 3 (FcRL3). In general, the ...

The motility of male gametes (sperm) is one of the important factors influencing the reproductive success of males. Because sperms are often subjected to strong postmating sexual selection and even closely related species often differ in sperm morphology, sperm motility could also differ between species, which may contribute to reproductive isolation between species. As part of my diploma thesis, I studied sperm motility in two closely related species of songbirds, the common nightingale (Luscinia megarhynchos) and the thrush nightingale (Luscinia luscinia). These two species of nightingales are an ideal model system because the areas of these two species overlap in the secondary contact zone across Central and Eastern Europe, where they occasionally hybridize and thus allow the study of speciation mechanisms in the natural environment. Both species also differ greatly in total sperm length. As part of my diploma thesis, I studied the possible influence of different sperm morphology on their motility. I further tested whether the motility of nightingale sperm differs in the fluid from the cloaca of a female of the same species and a different species, which would demonstrate the presence of postmating prezygotic reproductive isolation between species. The results of my work showed that despite the...

The oviduct plays an important role in the complex process of fertilization and in the early phase of embryo development. Isolation and characterization of some components of bovine oviduct participating in the formation of oviductal sperm reservoir was a subject of the present study. Two affinity sorbents containing immobilized components of bull seminal plasma (non-separated proteins of bull seminal plasma and their phosphorylcholine binding fraction) were prepared and used for the study of interaction of immobilized ligands with components of oviductal epithelium. Two types of preparation of oviductal membrane proteins of the isthmus region were isolated: complete membrane proteins and the apical fraction of membrane proteins. These preparations were separated using prepared affinity matrices. in both cases only an insignificant amount of proteins was found in the adsorbed fractions. Further attention has been paid to the identification of four protein zones detected after electrophoretic separation in the presence of SDS (rel. mol. wt. 15 500 - 18 500) in the fraction of apical membrane proteins. These proteins were identified after the electrophoretic separation and tryptic digestion using MS analysis as bovine histones H4, H2A typ 2-C, H2B typ 1-K a H3.3. Proteins identified as bovine...

Interactions between proteins and saccharide moieties play an indispensable role in mammalian reproduction as they stand behind of such processes as maturation and mutual recognition of gametes and sperm oviductal reservoir formation. In my dissertation thesis I focused on activities of glycosidases from bovine and porcine follicular fluids and their changes connected with follicle development. Activities of five glycosidases were detected in tertiary and preovulatory follicles in both species. The most active enzymes were α-L-fucosidase in cow and α-D-mannosidase in sow and both enzymes also demonstrated the most pronounced increase in their activities during follicle maturation. Interestingly, both α-L-fucose in cow and α-D-mannose in sow were described as saccharides responsible for the formation of the sperm oviductal reservoir and we offered a hypothetical mechanism of synchronisation between sperm release from their reservoir with the time of ovulation based on a surge of activities of corresponding follicular glycosidases through the oviduct. Subsequently, it was demonstrated that β-D-galactosidase and α-D-mannosidase affect sperm-zona pellucida binding in pig, as they both decrease interaction between sperm receptors for zona pellucida and zona pellucida. This may explain the observation...

The object of this study is to design demembranation method on four freshwater species and its application on study of the influence of HgCl2 on the axoneme and motity sperm motility parameters. Demembranation was designed and examined for all investigated species common carp (Cyprinus carpio), sterlet (Acipenser ruthenus), perch (Perca fluviatilis) and african catfish (Clarias gariepinus). One-step and two-step method was designed and tested for common carp. One-step method was designed for sterlet and perch. Two-step method of demembranation was designed for african catfish. Demembranation was designed and examined for all species under examination. Sperm motility was evidently increased above normal physiological value. Other sperm motility parameters (velocity, percent of motile cells) slightly decreased. HgCl2 in concentration 0,01 mM to the demembranation medium didn't show effect on flagellar microtubule aparat and then to the motility parameters, except sterlet; demembranated sterlet sperm was inhibited at all used concentration of HgCl2. Concentration 0,1 mM had inhibition effect on carp and africant catfish spermatozoa. Concentration 1 mM HgCl2 inhibited sperm of all tested species.

Infertility is the inability to achieve a pregnancy. WHO classify infertility into two groups. Primary infertility is the term used to describe a couple that has never been able to conceive a pregnancy, after at least 1 year of unprotected intercourse. Secondary infertility describes couples who have previously been pregnant at least once, but have not been able to achieve another pregnancy. Causes of infertility include a wide range of physical as well as emotional factors. Approximately 30 - 40% of all infertility is due to a "male" factor such as retrograde ejaculation, impotence hormone deficiency, environmental pollutants, scarring from sexually transmitted disease, or decreased sperm count. A "female" factor -- scarring from sexually transmitted disease or endometriosis, ovulation dysfunction, poor nutrition, hormone imbalance, ovarian cysts, pelvic infection, tumor or transport system abnormality from the cervix through the fallopian tubes -- is responsible for 40 - 50% of infertility in couples. The remaining 10 -30% of infertility cases may be caused by contributing factors from both partners, or no cause can be identified. This dissertation has two main goals. The first goal is to describe how a couple face up to their problems with infertility. The second goal is that this dissertation can be used as a study material for social and medical employees. This dessertation is based on a qualitative research. I used a method CAMI {--} communication through the use of computer. The observational goup were people disccusing at www.neplodnost.cz.