Non melanoma skin cancer pathogenesis overview

(1)Background: Non-melanoma skin cancer is the most frequently diagnosed cancer in humans. The process of skin carcinogenesis is still not fully understood. However, several studies have been conducted to better explain the mechanisms that lead to malignancy; (2) Methods: We reviewed the more recent literature about the pathogenesis of non-melanoma skin cancer focusing on basal cell carcinomas, squamous cell carcinoma and actinic keratosis; (3) Results: Several papers reported genetic and molecular alterations leading to non-melanoma skin cancer. Plenty of risk factors are involved in non-melanoma skin cancer pathogenesis, including genetic and molecular alterations, immunosuppression, and ultraviolet radiation; (4) Conclusion: Although skin carcinogenesis is still not fully understood, several papers demonstrated that genetic and molecular alterations are involved in this process. In addition, plenty of non-melanoma skin cancer risk factors are now known, allowing for an effective prevention of non-melanoma skin cancer development. Compared to other papers on the same topic, our review focused on molecular and genetic factors and analyzed in detail several factors involved in non-melanoma skin cancer

Feeding Dairy Cattle

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Antimicrobial activity of carbon-based fillers

Diplomová práce se zabývá vlivem uhlíkatého plniva na životaschopnost a produkci extracelulárních látek vybrané bakterie Bacillus subtilis (CCM 1999) a kvasinky Yarrowia lipolytica (CCY 29-26-52). Antimikrobiální aktivita těchto částic, přítomných v kultivačním mediu, byla sledována pomocí následujících parametrů: růst daného mikroorganismu, produkce extracelulárních proteinů a v poslední řadě byla monitorována produkce extracelulárních polymerních substancí, které mají úzkou souvislost s tvorbou biofilmu. Suspenze materiálů (0,135 mg/mL) byly připraveny ve dvou rozdílných kultivačních mediích; tzn. živné medium s obsahem glukózy pro Bacillus subtilis a bazální medium s přídavkem Tweenu 80 pro Yarrowia lipolytica, a media byla inokulována příslušným typem mikroorganismu. Experimenty probíhaly po dobu 6 dnů při rychlosti třepání 160 rpm a teplotě 30 °C pro Bacillus subtilis a 28 °C pro Yarrowia lipolytica. Testovány byly celkem tři typy uhlíkatého nanomateriálu, získané z Katedry anorganické chemie, Vysoké školy chemicko-technologické v Praze. Tyto materiály specifikované jako materiál “A”, “B” a “C” se navzájem lišily velikostí částic a stupněm oxidace. Na základě skríningových studií byla vybrána koncentrace testovaného materiálu 0,135 mg/mL a rychlost třepání 160 rpm. Metodou měření optické hustoty vzorku při 600 nm byly sestaveny a porovnány růstové křivky obou mikroorganismů v přítomnosti testovaných nanočástic po dobu 5 dní. Tímto způsobem bylo zjištěno, že přítomnost nanočástic v mediu nemá velký vliv na růst zkoumaného mikroorganismu. Tato metoda, je však pouze orientační, protože se nevyhneme chybě díky přítomnosti mrtvých buněk. Dále byla testována produkce celkových a extracelulárních proteinů daným mikroorganismem v přítomnosti testovaných nanočástic. Nebyla však pozorována výrazná odchylka hodnot od hodnot kontrolního vzorku, který neobsahoval testovaný materiál. Na základě metod počítání kolonií (Bacillus subtilis) a buněk (Yarrowia lipolytica) byly určeny ztráty životaschopnosti mikroorganismu ve 3 časech (6, 48 a 144 hodin); v kratším časovém intervalu byl růst spíše podporován. Dále byla monitorována produkce extracelulárních polymerních substancí (EPS), tedy proteinů, redukujících substancí a polysacharidů. Tyto látky byly vylučovány daným mikroorganismem do prostředí v průběhu 24 hodin. Bacillus subtilis produkoval EPS ve větší míře než Yarrowia lipolytica. Předpokládáme, že produkce EPS by mohla souviset s tvorbou biofilmu, který chrání buňky před toxicitou nanočástic.The aim of this diploma thesis is focused on the impact of carbon-based fillers on viability and extracellular substances production by bacterium Bacillus subtilis (CCM 1999) and yeast Yarrowia lipolytica (CCY 29-26-52). Antimicrobial activity of these particles, present in cultivation nutrient medium was examined using following parameters: growth of mentioned microorganisms, production of extracellular proteins and finally extracellular polymeric substances production, which is strongly connected with biofilm formation. Nanomaterials suspension (0.135 mg/mL) was prepared in two different cultivation media i.e. nutrient medium supplemented with glucose for Bacillus subtilis and basal medium with the addition of 2% (vol.) Tween 80 for Yarrowia lipolytica and media were inoculated by appropriate type of microorganism. Experiments were performed for 6 days under shaking rate at 160 rpm and at temperature of 30 °C for Bacillus subtilis and 28 °C for Yarrowia lipolytica. Three types of carbon nanomaterials obtained from Department of Inorganic Chemistry, Institute of Chemical Technology, Prague were examined. These materials specified as material “A”, “B” and “C” are mutually different by the size of its particles and the degree of oxidation. Based on the screening studies the tested material concentration of 0.135 mg/mL and shaking rate of 160 rpm were chosen. According to the optical density measurement at 600 nm, the growth curves of both microorganisms in the presence of tested nanoparticles during 5 days period were compared. It was find out, that the presence of nanoparticles don’t have a significant influence on tested microorganisms growth, by this technique. However, this method is just wider point of view, due to mistakes caused by presence of dead cells. Further, production of total cells proteins and extracellular proteins by microorganisms in presence of tested nanoparticles was examined. There was not observed any significant deviation from control samples values, where the tested materials were absent. Based on colony counting method (used for Bacillus subtilis) and cells counting in Bürker counting chamber (used for Yarrowia lipolytica), loss of microorganism viability was determined in 3 cultivation periods (6, 48 and 144 hours); there was observed a support of growth of microorganisms rather in shorter incubation period. Thereafter the extracellular polymeric substances (EPS) production that means proteins, reducing substances and polysaccharides was monitored. These substances were secreted into the medium by mentioned microorganisms during 24 hours of incubation. Bacillus subtilis cells produce much more EPS than Yarrowia lipolytica cells. We suppose that the EPS production could be closely associated with production of biofilm, which protects cells against nanoparticles toxicity.

Multiple Sequence Alignment of Transmembrane Beta-Barrel Proteins

The two main types of transmembrane proteins are transmembrane alpha helices (TMAH) and transmembrane beta-barrels (TMBB). From literature, we know that both are responsible for diverse biologically important functions. Since there is plenty of sequence and structural data available on various TMAH proteins, many techniques have been developed to analyze their sequence. On the contrary, not many TMBB proteins have been identified or studied. One of the most powerful sequence analysis techniques used for identifying and annotating the biological sequences is “Multiple Sequence Alignment” (MSA). It is often used for phylogenetic analysis, identification of conserved regions in the sequences, prediction of the topology of proteins, etc. High-throughput sequencing methods generate huge volume of sequence data, but they remain largely unannotated. Hence an MSA method for TMBB would be important for sequence-based studies and identifying more of such proteins. In this thesis, we apply a method called homology extension to the MSA and adjust the strategy applied by TMCoffee, a state of the art MSA method tested for TMAH, to make it suitable for TMBB proteins. We focus on extensively evaluating this method and comparing it with popular MSA tools