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- ItemComparison of Fungal Thermophilic and Mesophilic Catalase-Peroxidases for Their Antioxidative Properties(MDPI, 2023-07-04) Poljovka, Andrej; Musil, Miloš; Bednář, David; Chovanová, Katarína; Bauerová-Hlinková, Vladena; Bellová, Jana; Kohútová, Lenka; Baráth, Peter; Zámocký, MarcelCatalase-peroxidases (KatGs) are unique bifunctional oxidoreductases that contain heme in their active centers allowing both the peroxidatic and catalatic reaction modes. These originally bacterial enzymes are broadly distributed among various fungi allowing them to cope with reactive oxygen species present in the environment or inside the cells. We used various biophysical, biochemical, and bioinformatics methods to investigate differences between catalase-peroxidases originating in thermophilic and mesophilic fungi from different habitats. Our results indicate that the architecture of the active center with a specific post-translational modification is highly similar in mesophilic and thermophilic KatG and also the peroxidatic acitivity with ABTS, guaiacol, and L-DOPA. However, only the thermophilic variant CthedisKatG reveals increased manganese peroxidase activity at elevated temperatures. The catalatic activity releasing molecular oxygen is comparable between CthedisKatG and mesophilic MagKatG1 over a broad temperature range. Two constructed point mutations in the active center were performed selectively blocking the formation of described post-translational modification in the active center. They exhibited a total loss of catalatic activity and changes in the peroxidatic activity. Our results indicate the capacity of bifunctional heme enzymes in the variable reactivity for potential biotech applications.
- ItemMetering Homes: Do Energy Efficiency and Privacy Need to be in Conflict?(SciTePress - Science and Technology Publications, 2022-07-11) Polčák, Libor; Matoušek, PetrThe European directive on energy efficiency requires that all meters in multi-apartment buildings
installed after 25 October 2020 shall be remotely readable devices where technically feasible and
cost effective in terms of being proportionate in relation to the potential energy savings. In
practise, this means that some manufacturers produce meters that monitor energy consumption
in very short intervals, for example, less than two minutes; even though the directive expects to
provide billing information to consumers only once a month starting from 2022. This paper
reviews privacy and security risks stemming from the short readouts and provides
recommendations for manufacturers and suppliers. The paper focuses on a Wireless M-Bus
metering devices that we observed being sold and advertised as the solution to fulfill the
European directive on energy efficiency requirements. Nevertheless, we believe that many
recommendations and observations are applicable also to other protocols. - ItemSatellite DNA and Transposable Elements in Seabuckthorn (Hippophae rhamnoides), a Dioecious Plant with Small Y and Large X Chromosomes(2017-02-02) Puterová, Janka; Razumova, Olga; Martínek, Tomáš; Alexandrov, Oleg; Divashuk, Mikhail; Kubát, Zdeněk; Hobza, Roman; Karlov, Gennady; Kejnovský, EduardSeabuckthorn (Hippophae rhamnoides) is a dioecious shrub commonly used in the pharmaceutical, cosmetic, and environmental industry as a source of oil, minerals and vitamins. In this study, we analyzed the transposable elements and satellites in its genome.We carried out Illumina DNA sequencing and reconstructed the main repetitive DNA sequences. For data analysis, we developed a new bioinformatics approach for advanced satellite DNA analysis and showed that about 25% of the genome consists of satellite DNA and about 24% is formed of transposable elements, dominated by Ty3/Gypsy and Ty1/Copia LTR retrotransposons. FISH mapping revealed X chromosome-accumulated, Y chromosome-specific or both sex chromosomes-accumulated satellites but most satellites were found on autosomes. Transposable elements were located mostly in the subtelomeres of all chromosomes. The 5S rDNA and 45S rDNA were localized on one autosomal locus each. Although we demonstrated the small size of the Y chromosome of the seabuckthorn and accumulated satellite DNA there, we were unable to estimate the age and extent of the Y chromosome degeneration. Analysis of dioecious relatives such as Shepherdia would shed more light on the evolution of these sex chromosomes.
- ItemDNS over HTTPS Detection Using Standard Flow Telemetry(IEEE, 2023-01-31) Jeřábek, Kamil; Hynek, Karel; Ryšavý, Ondřej; Burgetová, IvanaThe aim of DNS over HTTPS (DoH) is to enhance users’ privacy by encrypting DNS. However, it also enables adversaries to bypass security mechanisms that rely on inspecting unencrypted DNS. Therefore in some networks, it is crucial to detect and block DoH to maintain security. Unfortunately, DoH is particularly challenging to detect, because it is designed to blend into regular HTTPS traffic. So far, there have been numerous proposals for DoH detection; however, they rely on specialized flow monitoring software that can export complex features that cannot be often computed on the running sequence or suffer from low accuracy. These properties significantly limit their mass deployment into real-world environments. Therefore this study proposes a novel DoH detector that uses IP-based, machine learning, and active probing techniques to detect DoH effectively with standard flow monitoring software. The use of classical flow features also enables its deployment in any network infrastructure with flow-monitoring appliances such as intelligent switches, firewalls, or routers. The proposed approach was tested using lab-created and real-world ISP-based network data and achieved a high classification accuracy of 0.999 and an F1 score of 0.998 with no false positives.
- ItemResponsible And Safe Home Metering: How to Design A Privacy-Friendly Metering System?(IGI Global, 2023-04-03) Polčák, LiborThe European directive on energy efficiency requires that all meters in multi-apartment buildings installed after 25 October 2020 shall be remotely readable devices when technically feasible and cost-effective in terms of being proportionate to the potential energy savings. The European Commission Recommendation of 9 March 2012 on preparations for the roll-out of smart metering systems (2012/148/EU) explicitly mentions that smart metering predominantly processes personal data. This chapter recommends how to design a metering system that fully conforms to legal regulations. The main contribution is the recommendation of eight steps for data controllers that make metering systems legally compliant. Additionally, the chapter lists recommendations for smart meter manufacturers that remove the burden of being a controller of the processing. The recommendations apply to the distribution of electricity, water, gas, heat, cooling, and other energies. The chapter shows that the recommendations can be generalized for smart home deployments.