|
| |
|
|
Role of microorganisms in the evolution of reproductive strategies in birds
Novotná, Lucie ; Javůrková, Veronika (advisor) ; Ferenc, Michal (referee)
Microorganisms are ubiquitous and can be found on the body of birds, in avian nests or may be carried into the nest along with nest-lining material. Microorganisms may therefore colonize eggshells of eggs in a clutch and subsequently penetrate into the egg contents. This so called trans-shell infection has been observed to affect hatching success, cause embryo mortality or subsequently influence hatchlings phenotype. Nevertheless, the probability of eggshell bacterial load or trans-shell infection depends on many factors, including environmental conditions, nest type, incubation pattern, and nest-lining material. Furthermore, some modifications of avian reproductive strategies may lead to reduction of negative effect of trans-shell infections, and significantly improve reproductive success. These mechanisms include incubation, mechanical and chemical barriers of egg, eggshell pigments or using of feathers and specific plants as nest lining material. Based on these findings, it can be concluded that the different reproductive strategies in birds should be a result of strong selective pressure caused by microorganisms. Although many recent studies have supported this assumption, research on this issue still suffers from many methodological shortcomings that must be eliminated in future studies.
|
|
|
Diversity and evolutionary significance of feather-degrading bacteria in birds
Kyptová, Markéta ; Javůrková, Veronika (advisor) ; Reif, Jiří (referee)
Although to date this fact has been widely neglected, avian plumage is inhabited by a wide range of bacteria able to utilize keratin, the basic structural unit of feathers. If these keratinophilic, so called feather-degrading bacteria (hereafter FDB) get out of control, it can lead to significant changes in the plumage structural properties, resulting in impaired thermoregulation, flight performance, and expression of plumage ornaments. These may have significant consequences on reproductive success and overall fitness of individual. Based on these facts, it is hypothesized that PDB pose strong selective pressure lying behind the evolution of defense mechanisms such as size and chemical composition of uropygial gland, deposition of pigments into the feathers, or molting strategies that have been observed to eliminate the negative effect of FDB. The aims of this bachelor thesis are, on the basis of available literature, to summarize findings related to overall diversity and characteristics of plumage bacteria, to evaluate their effect on quality of plumage and individual fitness, and also to assess a role of microorganism in the evolution of different life- strategies in birds. Finally, this bachelor thesis points out the shortcomings of recent studies and proposes the concept for future research...
|
|
|
Temperature-dependent activity of egg-white antimicrobial proteins in precocial and altricial birds
Novotná, Lucie ; Javůrková, Veronika (advisor) ; Krist, Miloš (referee)
Microorganisms are considered to be crucial selective factor affecting reproductive success of birds. It is hypothesized that egg-white antimicrobial proteins and incubation behavior are the most important defense mechanisms that eliminates the risk of microbial trans-shell infection. The latest studies supposed that incubation temperatures may significantly affect the antimicrobial activity of egg white proteins. The concentration of egg white antimicrobial proteins as well as incubation patterns differ among altricial and precocial species of birds. However, experimental study testing the effect of incubation temperature on the antimicrobial potential of antimicrobial egg white proteins in altricial and precocial birds is missing. In this study we tested in manipulative experiment the effect of partial and full incubation, the concentration of lysozyme and ovotransferrin and their interactions on the antimicrobial activity of egg whites of two model species - Japanese quail (Coturnix japonica) and home pigeon (Columba livia). Antimicrobial protein activity was determined by the agar well diffusion method against two Gram-positive bacteria - Bacillus subtilis and Micrococcus luteus that have been documented as pathogenic egg-white invaders of several birds. Moreover, we analyzed the effect of...
|
|
| |
|
| |
|
|
Investment in reproduction and nest defense in waterfowl
Javůrková, Veronika ; Albrecht, Tomáš (advisor) ; Remeš, Vladimír (referee) ; Weidinger, Karel (referee)
Investment in reproduction is considered to be crucial component of life history traits. Reproductive success is however constrained by generally unpredictable environmental conditions. Based on "bet hedging" theory, individuals are forced to eliminate such unpredictability via the mixed strategy to maximize their long-term fitness. Predation represents underlying factor affecting individual reproductive success, and it undoubtedly lies behind the evolution of alternative reproductive strategies such as extra-pair paternity and conspecific brood parasitism. Behavioral mechanisms related to nest defense are thought to be investment in reproduction in accordance with trade-off between actual and residual reproductive value. Despite the extensive interest in the principles associated with parental investment into the nest defense, studies describing in detail the pattern of particular antipredator strategies are rare. Similarly, mechanisms responsible for maintenance of egg- viability during prolonged egg-laying period in species delayed the onset of incubation are poorly understood. In accordance with mentioned themes, this thesis includes publications aimed at aspects of reproductive biology and antipredator behavior in Mallards (Anas platyrhynchos). Particular publications concretely documented: a)...
|
|
|
Mechanisms of relationship between melanin-based colouration and behavioural syndromes in birds
Nacházelová, Martina ; Javůrková, Veronika (advisor) ; Tomášek, Oldřich (referee)
Melanins are the most common pigments incorporated into birds' feathers. Since melanin-based coloration is variable in the extent and intensity, its function is considered to be particularly cryptic and mechanical, hardening the feather structure. However, recently it has been found that melanin- based coloration also has a signaling function, due to the observed correlation between this type of coloration and many physiological and behavioral traits. These relationships follow from the pleiotropic effects of genes regulating the melanocortin system and the physiological effects of testosterone and corticosterone, which are involved in melanogenesis. This work describes genetic and physiological mechanisms of the relationship between melanin-based coloration and behavioral traits in birds and, based on available studies, supports the signaling function of this type of coloration. Melanin-based coloration has been shown to be positively correlated with aggressiveness and dominance, sexual activity, coping with stress, a fast strategy of exploratory behavior, parental care, and anti-predator behavior in many bird species. However, despite intense research interest in this topic in last decade, it is worth noting that more experiments focused on species with a distinct sexual dichromatism or...
|
|
|
Case study of physiotherapy treatment of a patient with the diagnosis of status after ankle fracture osteosynthesis.
Javurková, Veronika ; Sohrová, Jana (advisor) ; Šáchová, Dana (referee)
Title: Case study of physiotherapy treatment of a patient with the diagnosis of status after ankle fracture osteosynthesis. Aim: The aim of this bachelor' s thesis is to present basic information on ankle fractures and to elaborate a case report of a patient with this diagnoses. Methods: This research was based on the processing of literature on the topic. It is divided into two parts - a general part and a special part. The general part contains basic information about anatomy and function of the ankle joint, kinesiology. It contains also traumatology, physioterapeutic methods and procedures that can be used in a patient with mentioned diagnosis. The special part contains casuistic of a patient and includes anamnestic data, input kinesiological analysis. The therapies are processed individually according to the patient' s attendance and are finished with the output of kinesiological analysis with evaluation of the therapy effects. Keywords: ankle joint, fracture, osteosynthesis, physiotherapy, case study
|
|
|
Ecological aspects affecting microbiota in the digestive tracts of birds
Schmiedová, Lucie ; Kreisinger, Jakub (advisor) ; Mrázek, Jakub (referee) ; Gvoždíková Javůrková, Veronika (referee)
The results indicate that songbird GM is dominated by the bacterial phyla Proteobacteria, Firmicutes, Actinobacteria, Tenericutes, Bacteroidetes and Chlamydia, a community that differs from that of mammals. A t the interspecies l evel, GM composition is mainly influenced by phylogeny and less so by sampling site. While ecological factors , and especially diet , are important GM predictors in mammals, the effect of ecological factors , including diet , have a much smaller effect on inte r - and intraspecific variability in songbird GM composition . Our data from barn swallows ( Hirundo rustica ) suggest an effect of social GM transmission among adults forming social pair s, as well as trans - generational transmission from a social mother to her own nestlings. At the same time, we observed differ ing GM in adults and nestlings, with no dramatic change in GM with nestling age, a process previously recognised in mammals. Part of the GM detected appears to remain stable over time , and is therefore su itable for further detailed study. To conclude, our studies demonstrate that s ongbird GM differs from that of mammals and that the factors influencing GM composition appear to differ from those in mammals , thereby highlighting the importance of study ing mu ltiple vertebrate groups (not just mammals ) when...
|
guest ::
RSS feed.