43 research outputs found
Economic Situation and Law Regulation of Public Broadcasters in Czech republic and Specific Central European Countries
Import 02/11/2016Bakalářská práce se zabývá realitou veřejnoprávních televizí ve vybraných zemích střední Evropy, konkrétně v České republice, na Slovensku, v Polsku a v Maďarsku. Okrajově se v žurnalistické části zajímá také o to, jak fungují média veřejné služby v Německu a to z důvodu stručné historické komparace. V úvodu práce popisuje a vysvětluje obecné principy veřejnoprávního vysílání, připomíná některé koncepty a připouští kritiku současných vysílacích modelů. V další části se zabývá tím, zda je veřejnoprávní vysílání pro společnost výhodné a stojí za to si jej různými prostředky udržovat. V závěrečných kapitolách využívám dosud popsaných jevů k sestavení žurnalistických komunikátů – úvodního článku subjektivně reflektujícího skutečnou realitu České televize jako nejsilnějšího veřejnoprávního média v regionu, publicistického interview se socioložkou zabývající se fungováním masmédií, ankety se známými osobnostmi české mediální scény a fejetonu jako publicistického žánru subjektivně komentujícího fragment dění kolem ČT.This thesis deals with the reality of public broadcasters in selected countries of Central Europe, namely the Czech Republic, Slovak Republic, Poland and Hungary. Marginally, is this thesis interested in how public service media works, due to historical comparation.The introduction describes and explains the general principles of public service broadcasting, recalling some concepts and accepts criticism of the current broadcasting model. The next section examines whether public service broadcasting is beneficial to society, and if it is worth to keep. The final chapters, I use the previously described phenomenon to write journalistic article which is introducing the reality of Czech TV as the strongest public media in region of Central Europe. Next, I did a journalistic interview with sociologist on the functioning of mass media which is accompagned by an opinion poll with respected czech journalists. This bachelor thesis ends with specific article which is subjectively pointing at key issue of whole problem.121 - Katedra ekonomické žurnalistikyvýborn
Membrane shaping by actin and myosin during regulated exocytosis
The cortical actin network in neurosecretory cells is a dense mesh of actin filaments underlying the plasma membrane. Interaction of actomyosin with vesicular membranes or the plasma membrane is vital for tethering, retention, transport as well as fusion and fission of exo- and endocytic membrane structures. During regulated exocytosis the cortical actin network undergoes dramatic changes in morphology to accommodate vesicle docking, fusion and replenishment. Most of these processes involve plasma membrane Phosphoinositides (PIP) and investigating the interactions between the actin cortex and secretory structures has become a hotbed for research in recent years. Actin remodelling leads to filopodia outgrowth and the creation of new fusion sites in neurosecretory cells and actin, myosin and dynamin actively shape and maintain the fusion pore of secretory vesicles. Changes in viscoelastic properties of the actin cortex can facilitate vesicular transport and lead to docking and priming of vesicle at the plasma membrane. Small GTPase actin mediators control the state of the cortical actin network and influence vesicular access to their docking and fusion sites. These changes potentially affect membrane properties such as tension and fluidity as well as the mobility of embedded proteins and could influence the processes leading to both exo- and endocytosis. Here we discuss the multitudes of actin and membrane interactions that control successive steps underpinning regulated exocytosis
Amnion cells engineering: A new perspective in fetal membrane healing after intrauterine surgery?
In this study we aimed to set up an in vitro culture of the rabbit amnion in order to support in vivo fetal membrane healing capacity following fetoscopy. Fetal membranes were collected from a mid- gestational rabbit, and cultured on collagen support material for 14 days. 34 rabbits at 22 - 23 days gestational age ( GA) underwent fetoscopy. The entry site was randomly allocated to 4 closure technique study groups: group I, human amnion membrane ( n = 23); group II, collagen foil ( n = 16); group III, collagen plug ( n = 19), and group IV, collagen plug with cultured amnion cells ( n = 19). In all groups membrane access sites were additionally sealed with fibrin sealant, and the myometrium was closed with sutures. Fetal survival, amnion membrane integrity, and the presence of amniotic fluid were evaluated at 30 days GA. Cultures showed good survival in the collagen support material. Increased cellularity, survival and proliferations were observed. The amnion at the access site resealed in 58 - 64% of cases in groups II - IV, but none of the tested techniques was significantly better than the other. Histological examination indirectly revealed the anatomic repair of the membranes, since no entrapment of the membranes could be demonstrated in the myometrial wound. Copyright (c) 2006 S. Karger AG, Basel
An acto-myosin II constricting ring initiates the fission of activity-dependent bulk endosomes in neurosecretory cells
Activity-dependent bulk endocytosis allows neurons to internalize large portions of the plasma membrane in response to stimulation. However, whether this critical type of compensatory endocytosis is unique to neurons or also occurs in other excitable cells is currently unknown. Here we used fluorescent 70 kDa dextran to demonstrate that secretagogue-induced bulk endocytosis also occurs in bovine chromaffin cells. The relatively large size of the bulk endosomes found in this model allowed us to investigate how the neck of the budding endosomes constricts to allow efficient recruitment of the fission machinery. Using time-lapse imaging of Lifeact–GFP-transfected chromaffin cells in combination with fluorescent 70 kDa dextran, we detected acto-myosin II rings surrounding dextran-positive budding endosomes. Importantly, these rings were transient and contracted before disappearing, suggesting that they might be involved in restricting the size of the budding endosome neck. Based on the complete recovery of dextran fluorescence after photobleaching, we demonstrated that the actin ring-associated budding endosomes were still connected with the extracellular fluid. In contrast, no such recovery was observed following the constriction and disappearance of the actin rings, suggesting that these structures were pinched-off endosomes. Finally, we showed that the rings were initiated by a circular array of phosphatidylinositol(4,5)bisphosphate microdomains, and that their constriction was sensitive to both myosin II and dynamin inhibition. The acto-myosin II rings therefore play a key role in constricting the neck of budding bulk endosomes before dynamin-dependent fission from the plasma membrane of neurosecretory cells
Secretagogue stimulation of neurosecretory cells elicits filopodial extensions uncovering new functional release sites
Regulated exocytosis in neurosecretory cells relies on the timely fusion of secretory granules (SGs) with the plasma membrane. Secretagogue stimulation leads to an enlargement of the cell footprint (surface area in contact with the coverslip), an effect previously attributed to exocytic fusion of SGs with the plasma membrane. Using total internal reflection fluorescence microscopy, we reveal the formation of filopodia-like structures in bovine chromaffin and PC12 cells driving the footprint expansion, suggesting the involvement of cortical actin network remodeling in this process. Using exocytosis-incompetent PC12 cells, we demonstrate that footprint enlargement is largely independent of SG fusion, suggesting that vesicular exocytic fusion plays a relatively minor role in filopodial expansion. The footprint periphery, including filopodia, undergoes extensive F-actin remodeling, an effect abolished by the actomyosin inhibitors cytochalasin D and blebbistatin. Imaging of both Lifeact-GFP and the SG marker protein neuropeptide Y-mCherry reveals that SGs actively translocate along newly forming actin tracks before undergoing fusion. Together, these data demonstrate that neurosecretory cells regulate the number of SGs undergoing exocytosis during sustained stimulation by controlling vesicular mobilization and translocation to the plasma membrane through actin remodeling. Such remodeling facilitates the de novo formation of fusion sites
Activity-driven relaxation of the cortical actomyosin II network synchronizes Munc18-1-dependent neurosecretory vesicle docking
In neurosecretory cells, secretory vesicles (SVs) undergo Ca2(+)-dependent fusion with the plasma membrane to release neurotransmitters. How SVs cross the dense mesh of the cortical actin network to reach the plasma membrane remains unclear. Here we reveal that, in bovine chromaffin cells, SVs embedded in the cortical actin network undergo a highly synchronized transition towards the plasma membrane and Munc18-1-dependent docking in response to secretagogues. This movement coincides with a translocation of the cortical actin network in the same direction. Both effects are abolished by the knockdown or the pharmacological inhibition of myosin II, suggesting changes in actomyosin-generated forces across the cell cortex. Indeed, we report a reduction in cortical actin network tension elicited on secretagogue stimulation that is sensitive to myosin II inhibition. We reveal that the cortical actin network acts as a 'casting net' that undergoes activity-dependent relaxation, thereby driving tethered SVs towards the plasma membrane where they undergo Munc18-1-dependent docking
Myosin VI small insert isoform maintains exocytosis by tethering secretory granules to the cortical actin.
Before undergoing neuroexocytosis, secretory granules (SGs) are mobilized and tethered to the cortical actin network by an unknown mechanism. Using an SG pull-down assay and mass spectrometry, we found that myosin VI was recruited to SGs in a Ca(2+)-dependent manner. Interfering with myosin VI function in PC12 cells reduced the density of SGs near the plasma membrane without affecting their biogenesis. Myosin VI knockdown selectively impaired a late phase of exocytosis, consistent with a replenishment defect. This exocytic defect was selectively rescued by expression of the myosin VI small insert (SI) isoform, which efficiently tethered SGs to the cortical actin network. These myosin VI SI-specific effects were prevented by deletion of a c-Src kinase phosphorylation DYD motif, identified in silico. Myosin VI SI thus recruits SGs to the cortical actin network, potentially via c-Src phosphorylation, thereby maintaining an active pool of SGs near the plasma membrane
Subdiffractional tracking of internalized molecules reveals heterogeneous motion states of synaptic vesicles
The ČTK as a source of main television news sessions
This diploma thesis is describing the influence of Czech Press Agency on major television news programs. Theoretical part is defining, what the agenda setting is and how medias handles agency news. Significant part is also dealing with description a characteristic of media functioning. In practical part, author is measuring the influence of Czech Press Agency by using method known as quantitative content analysis. As proven, agency have a significant, but limited influence on televion broadcasting news. Thesis in last part deals in detail with the analysis of this influence.Diplomová práce se zabývá zkoumáním vlivu agenturního servisu České tiskové kanceláře na podobu televizního zpravodajství. V teoretické části se zabývá popisem a charakteristikou zkoumaných médií a přináší některé zajímavé poznatky ohledně jejich fungování. Část práce je vyhrazená také definici agenda-settingu, tedy nastolování agendy. Stěžejní částí práce je charakteristika a výzkum hlavních zpravodajských relací tří celoplošných vysílatelů v České republice. Pro posouzení míry shody obsahů a vlivu použil autor této práce metodu kvantitativní obsahové analýzy. Závěry výzkumu prokázaly, že ČTK má významný vliv na podobu relací. Je ale omezen specifiky televizní žurnalistiky i charakterem jednotlivých médií.Katedra žurnalistikyDepartment of JournalismFakulta sociálních vědFaculty of Social Science
Proposal of a New Layout of Ostravská and Ke Hřišti Streets in Milovice
Předmětem diplomové práce „Návrh nového uspořádání ulic Ostravská a Ke Hřišti v Milovicích“ je analýza současného stavu dopravy a infrastruktury v oblasti Milovic. Tato oblast sloužila téměř 100 let pro různé účely armády a po jejím odchodu je snahou na místo opět přilákat nové obyvatele. V souvislosti s tím rychle narůstá počet obyvatel města a potřeba nutných úprav nevyhovující dopravní infrastruktury. Cílem práce je navrhnout taková řešení, která budou plně odpovídat příslušným normám a požadavkům dané lokality, a zároveň zajišťovat bezpečnost a plynulost silničního provozu.The subject of the diploma thesis „Proposal of new layout of Ostravská and Ke Hřišti streets in Milovice“ is an analysis of the current state of the traffic and of the transport infrastructure in the area. This area was used for military needs almost 100 years and after military leave from the area is an effort to attract new citizens to the area. Because of that, the number of citizens is increasing very fast and the need of the necessary wanting infrastructure adjustment as well. The aim is to propose such solutions which will fully comply with the relevant technical standards, to the road safety, to the flow of road traffic and to the requirements of the area