|
|
Circadian regulation of digestive system function and its disturbances due to external factors
Běloušková, Klára ; Sumová, Alena (advisor) ; Balounová, Kateřina (referee)
Circadian clocks regulate the behavior of cells in living organisms in 24hour periods. They react to environmental influences and, by synchronizing with them, ensure optimal cell function and the overall health of the organism. Biological clocks in the gastrointestinal tract and their functions can be influenced by several factors, including the timing of food intake or the influence of the microbiome. The correct timing of food intake can be essential in maintaining the functional physiology of the organism as well as the appropriate composition of the gut microbiome. Disruption of the synchronization between these factors and the biological clock in the gastrointestinal tract leads to disharmony of the organism, its improper function and the development of disease. The timing of food intake and the cultivation of an appropriate microbiome is critical to maintaining optimal health and should not be neglected by the public.
|
|
|
Peptides regulating food intake and their role in metabolic syndrome
Buderová, Markéta ; Maletínská, Lenka (advisor) ; Hojná, Silvie (referee)
Unhealthy lifestyle together with genetic factors can lead to serious health problems like metabolic syndrome (MetS). MetS is a cluster of risk factors such as abdominal obesity, dyslipidemia, insulin resistance and hypertension. Each component of MetS contributes to cardiovascular diseases, type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease. Treatment of MetS is primarily focused on lifestyle modification, especially weight loss. In severe cases, pharmacological treatment is also used. Pharmacological treatment includes peptide analogues that regulate food intake. Anorexigenic (food- reducing) peptides are involved in the regulation of food intake, together with orexigenic (food- increasing) peptides, which thus play an important role in maintaining energy homeostasis. Several analogues of anorexigenic peptides regulating food intake are already used for the treatment of obesity or T2DM. Other peptide analogues are in preclinical stages of testing or in the development of stable analogues. Elucidating the physiology and pathology of both anorexigenic and orexigenic peptides in the regulation of food intake may contribute to finding potential treatments for metabolic, cardiovascular, and other disorders.
|
|
|
Vliv teploty na oplozenost a líhnivost po krátkodobém skladování neoplozených jiker sumce velkého (Silurus glanis)
PŘIBYL, Tadeáš
The experiment validated the impact of storage of artificially spawned unfertilised eggs of European catfish on fertilization, hatching and the beginning of exogenous food intake throughout the transition from the embryonic to larval life period. The eggs from artificially spawned individuals have been used for this experiment using the induction of ovulation by the carp pituitary system. Sperm from each individual was collected by stripping using a hypodermic needle, that were partially filled with immobilising solution for sperm before artificial spawning of female individuals. Artificial stripping of fish was carried out under anaesthesia (by clove oil). Immediately after artificial hatching, samples of eggs (approximately 50 g) were put into six plastic bowls. Covered with wet cloth, bowls with eggs were placed into tempered, isolating thermo boxes with temperatures of 5, 10, 15, 20, 25 and 30 °C. Subsequently, in time intervals of 0,5, 1, 2, 3, 4, 6, 8 and 10 hours (after spawning) a small amount of eggs (approximately 50 pieces) was taken away from each temperature and put into glass beakers (with three repetitions), then the sperm was added and finally activated by adding water. In beakers with incubated non-sticking eggs and during the consequent storage of hatching embryos through temperature between 19,5-20 °C, water was changed two times a day. Approximately 4 hours after incubation, the exact number of used and fertilised eggs, was calculated. Unfertilised eggs (of white colour) and dead embryos were removed. Hatchery was assessed approximately 100 hours after fertilisation, when all living embryos had been hatched. After another 115 hours, throughout the transition from the embryonic to larval life development, live food (nauplia Artemia) was put into each bowl. Three hours after, individuals that began the food intake were calculated. The highest level of fertilisation was found in eggs stored between 0,5 and 2 hours (95,0?2,2 % - 100,0?0,0 %). The decrease in fertilisation is noticeable in all tested groups after 3 hours from stripping. Statistically significant decrease in fertilization was detected in eggs stored for 6 hours, the storage temperature did not affect the fertilization. Similar results have been maintained also in hatchery, where hatchery decreases as storage time increases. The highest level of hatchery was found in eggs stored in 25 °C (for 0,5 h 61,4?5,5 %), or more precisely 1 h 42,8?12,9 %). Hatching significantly decreases in all storage temperatures when storage time is longer than half an hour. The last parameter concerned how many percent of the individuals began the food intake. The highest level was recorded in eggs stored for half an hour (after spawning) in 25 °C (60,1?5,3 %), 30 °C (54,5?17,7 %) and 20 °C (39,0?12,7 %). On the contrary, storage temperatures 5 °C, 10 °C and 15 °C had results between 8,9?2,8 % and 35,0?18,8 %. Total mortality was detected when the storage time was more than 8 hours. It is necessary to fertilize the eggs as soon as possible (max. up to half an hour) after spawning, and to avoid storage of eggs at low temperatures (below 15 °C), to obtain viable individuals.
|
|
|
Obesity its causes and cosequences
Ondráčková, Anna ; Vybíral, Stanislav (advisor) ; Kuda, Ondřej (referee)
Obesity is one of the most common health problems in the Word. Over 500 million adults and over 40 million children are obese. The aim of this work is to summarize findings of causes and consequences of this health problem. Even though in some cases only genetic mutations are responsible for obesity for example mutation in ob gene or Prader-Willi syndrome most cases are caused by lifestyle of people -excessive food intake and insufficient physical activity. There are many health problems accompanying obesity. The most serious problems are metabolic syndrome, diabetes mellitus, cardiovascular diseases and cancer. The consequences of obesity are, however, not confined only to health. We can also observe the economic consequences. Financial cost of treatment of obesity and related diseases are estimated in billions of dollars. Pharmacological treatment has so far proved to be ineffective. If drugs are effective, the side effects are so severe that their use is not possible. So far, the adipose tissue hormones that regulate food intake provide the best hope.
|
|
|
Vigilance and escape behaviour in ground squirrels (tribe Marmotini)
Milerová, Petra ; Vohralík, Vladimír (advisor) ; Matějů, Jan (referee)
In the ground squirrels, vigilant antipredator behaviour is frequently studied as a part of antipredator strategy. More vigilant animals have greater chances to avoid a predator attack. But it's also true, that animals allocating more time to vigilance, can allocate less time to foraging. There is obvious trade-off between vigilance and foraging. Ground squirrels, marmots and prairie dogs have to receive a lot of food to accumulate fat reserves for the hibernation period, and in case of juveniles also to ensure their growth. Therefore, they are forced to allocate time between aforementioned activities suitably. In view of the close relationship between vigilance and foraging, these two activities are often investigated together. The most important factors influencing aforementioned activities are number of simultaneously active individuals and presence of visual barriers. An affect has also age, sex and reproductive status of the individual or caloric content of the food. After the detection of a predator with the aid of vigilance, can be initiated escape response. Escape distance, escape velocity and escape behaviour in general are influenced especially by the type of predator, type of vegetation cover and individual distance from a burrow entrance. It is important that total energy costs of these...
|
|
|
Neuropeptide Y and food intake regulation
Váchová, Barbora ; Nedvídková, Jara (advisor) ; Telenský, Petr (referee)
Neuropeptide Y (NPY) is a 36-amino acid member of NPY family. Its biosynthesis occurs in the hypothalamus and its expression also in adipose tissue was described in 2007. NPY is an ubiquitous hormone with central and peripheral effects which lead to the maintenance of homeostasis; NPY is also one of the most significant orexigenic hormones. NPY utilizes G-protein coupled receptors Y1, Y2 and Y5 for its food intake regulation; owing to serious side effects of currently used anti-obesity drugs, the ligands of these receptors (Y1R and Y5R antagonists and Y2R agonists) are considered as targeting molecules for a new therapeutic strategy for obesity treatment. This work is focused on the characteristic of NPY as an orexigenic agent and the possibility of using NPY-based drugs for obesity treatment.
|
|
|
Peptides regulating food intake and their lipidized analogs for possible treatment of obesity and cachexia
Buková, Anna-Marie ; Maletínská, Lenka (advisor) ; Janovská, Petra (referee)
In spite of good living conditions, the number of people in the state where the total food intake or individual nutrients is insufficient, unnecessary or unbalanced has increased in recent years. In case of superfluous food intake, amount of fat tissue increases and overweight and obesity appear, which is associated with an increased risk of type 2 of diabetes, cardiovascular disease or certain types of cancer. Insufficient intake of food may, for example, result in the function of the immune system, resulting in an increased risk of infection or poor wound healing. In addition to primary malnutrition, we can see malnutrition as the secondary manifestation of another illness. The state of weight loss and malnutrition caused by another disease is called cachexia. This is a serious complication of primary therapies. At present, in addition to established approaches to the treatment of these diseases, some studies address treatment options using compounds that influence the regulation of food intake. One group of these compounds is peptides able to reduce food intake (anorexigenic peptides) or increase it (orexigenic peptides). To these natural substances in the organism are also sought analogs with properties more favorable for use in practice. One of the possibilities are lipidized analogs, among...
|
|
|
Effects of PrRP (prolactin-releasing peptide) and NPFF (neuropeptide FF) analogs in vitro and in vivo
Tichá, Anežka ; Ryšlavá, Helena (advisor) ; Železná, Blanka (referee)
Prolactin-releasing peptide (PrRP) and neuropeptide FF (NPFF) belong to the RF-amide family. These peptides have identical C-terminal amino acid sequence (R-F-NH2) and similar biological activities. PrRP was identified as an endogenous ligand of an orphan receptor GPR10 able to stimulate PRL-secretion in vitro and in vivo, but soon it was discoverd that this is not the primary function of this peptide. PrRP is thought to be an anorexigenic peptide as PrRP and GPR10 are found in several parts of the brain responsible for food intake regulation and because both GPR10 and PrRP deficient mice suffer from hyperphagia and late-onset obesity. In this study, relationship between PrRP and NPFF was studied using both in vitro binding and sell signaling and in vivo food intake and analgesia test in mice. In vitro experiments showed that PrRP bound to rat pituitary RC-4B/C cells containing GPR10 receptor with high affinity and NPFF, its stable analog 1DMe and its antagonist RF9 up to 10-5 M concentration did not bind to GPR10. NPFF, 1DMe and PrRP were bound to cell membranes with transfected NPFF2 receptor with high affinity, but RF9 with low affinity in a range of 10-7 M, in contrast to published literature. In vivo experiments with fasted mice confirmed that centrally injected PrRP and NPFF significantly...
|
|
|
Peptide hormones affecting the food intake and their analogs as potential drugs for treatment of obesity
Nagelová, Veronika ; Maletínská, Lenka (advisor) ; Vybíral, Stanislav (referee)
Obesity is nowadays a major global health problem. Every year amount of obese (BMI > 30 kg . m-2 ) and overweight (BMI > 25 kg . m-2 ) people increases. Obesity is not just a cosmetic problem, but it leads to many serious health complications, particularly cardiovascular diseases, metabolic diseases etc. We can define obesity as an excessive amount of body fat. The development of obesity is often influenced by energy intake, which overrides the energy expenditure. Many studies are currently describe the influence of various substances that could potentially act as antiobesity drugs. Peptide hormones, which are engaged in this work, can be divided to the long-term (leptin, insulin, ghrelin) and short-term (e.g. cholecystokinin, glucagon like peptide 1, peptide YY, CART peptides, melanocortin system, neuropeptide Y and melanin concentrating hormone) acting. Peptides can be also divided according to their effect on food intake to the anorexigenic and orexigenic. Anorexigenic peptides reduce food intake, orexigenic do the reverse.
|
|
|
Impact of circadian system disruption on development of gastrointestinal disorders
Kubištová, Aneta ; Sumová, Alena (advisor) ; Červená, Kateřina (referee)
The ability to sense 24-hour cycles in external environment and to adapt to them is present in a great array of species living on the Earth. Mammals possess internal time-keeping system which is composed of circadian clocks located in the suprachiasmatic nuclei (SCN) of the hypotalamus and peripheral clocks in various tissues and organs of the body. These clocks are adapting to the changes of external environment, such as light and dark cycles or feeding cycles. Peripheral clocks in the organs of the digestive system are synchronized with the signals derived from the central clock in the SCN and also with signals from food intake. Discordance between these signals may result in development of various diseases of the gastrointestinal tract (GIT) related to insufficient digestion or even in higher risk of developing a cancer. This bachelor thesis is generally aimed at circadian rhythms in the body, with the focus on rhythms in the GIT. It will deal with the importance of the circadian rhythms for correct GIT functions. Furthermore, the thesis is focused on connection between the desynchonization of the circadian clock and GIT disease development, namely of obesity and cancer.
|
guest ::
