Biomimetic methods for obtaining materials from organic precursors

W pracy przedstawiono metody biomimetyczne otrzymywania materiałów. Przedstawiono dwa przykłady otrzymania materiałów o potencjalnym zastosowaniu w implantologii z wykorzystaniem metod hydrotermalnych oraz pirolizy i infiltracji. Jako prekursory zastosowano muszle mięczaków oraz różne gatunki drzew. Wykonano badania dyfraktometryczne oraz analizy mikroskopowe. Stwierdzono, że możliwe jest uzyskanie materiałów ceramicznych o oczekiwanej strukturze metodami biomimetycznymi.This paper presents the biomimetic methods of the obtaining materials. Two examples of the obtaining materials with the use of hydrothermal and pyrolysis and infiltration methods, with possibility to implants application, was showed. As a precursor the shells of shellfish and different type of wood was used. The X-ray and microscopic analysis were carried out. It was found that is possible to obtain the ceramic material with required structure by biomimetic methods

Cell-permeable nicotinamide adenine dinucleotides for exploration of cellular protein ADP-ribosylation

Posttranslational modifications (PTMs) greatly enhance the functional diversity of proteins, surpassing the number of gene-encoded variations. One intriguing PTM is ADP-ribosylation, which utilizes nicotinamide adenine dinucleotide (NAD+) as a substrate and is essential in cell signaling pathways regulating cellular responses. Here, we report the first cell-permeable NAD+ analogs and demonstrate their utility for investigating cellular ADP-ribosylation. Using a desthiobiotin-labelled analog for affinity enrichment of proteins that are ADP-ribosylated in living cells under oxidative stress, we identified protein targets associated with host-virus interactions, DNA damage and repair, protein biosynthesis, and ribosome biogenesis. Most of these targets have been noted in various literature sources, highlighting the potential of our probes for cellular ADP-ribosylome studies

N1-Propargylguanosine Modified mRNA Cap Analogs: Synthesis, Reactivity, and Applications to the Study of Cap-Binding Proteins

The mRNA 5′ cap consists of N7-methylguanosine bound by a 5′,5′-triphosphate bridge to the first nucleotide of the transcript. The cap interacts with various specific proteins and participates in all key mRNA-related processes, which may be of therapeutic relevance. There is a growing demand for new biophysical and biochemical methods to study cap−protein interactions and identify the factors which inhibit them. The development of such methods can be aided by the use of properly designed fluorescent molecular probes. Herein, we synthesized a new class of m7Gp3G cap derivatives modified with an alkyne handle at the N1-position of guanosine and, using alkyne-azide cycloaddition, we functionalized them with fluorescent tags to obtain potential probes. The cap derivatives and probes were evaluated in the context of two cap-binding proteins, eukaryotic translation initiation factor (eIF4E) and decapping scavenger (DcpS). Biochemical and biophysical studies revealed that N1-propargyl moiety did not significantly disturb cap−protein interaction. The fluorescent properties of the probes turned out to be in line with microscale thermophoresis (MST)-based binding assays

Karyotype Abnormalities in the X Chromosome Predict Response to the Growth Hormone Therapy in Turner Syndrome

Short stature is characteristic for Turner syndrome (TS) patients, and particular karyotype abnormalities of the X chromosome may be associated with different responsiveness to recombinant human GH (rhGH) therapy. The aim of the study was to analyze the effect of different types of TS karyotype abnormalities on the response to rhGH therapy. A total of 57 prepubertal patients with TS treated with rhGH with a 3 year follow-up were enrolled in the study and categorized according to their karyotype as X monosomy (n = 35), isochromosome (n = 11), marker chromosome (n = 5), or X-mosaicism (n = 6). Height and height velocity (HV) were evaluated annually. In the first year, all groups responded well to the therapy. In the second year, HV deteriorated significantly in X-monosomy and isochromosome in comparison to the remaining two groups (p = 0.0007). After 3 years of therapy, all patients improved the score in comparison to their target height, but better outcomes were achieved in patients with marker chromosome and X-mosaicism (p = 0.0072). X-monosomy or isochromosome determined a poorer response during the second and third year of rhGH therapy. The results of the study indicate that the effects of rhGH therapy in patients with TS may depend on the type of TS karyotype causing the syndrome

Assessment of Oral Health in Long-Term Enteral and Parenteral Nutrition Patients: Significant Aspects of Nursing Care

Oral health is an underestimated factor affecting overall human health and quality of life. Long-term enteral or parenteral nutritional treatment requires not only regular assessment of access routes, the patient’s nutritional status, and tolerance to the selected method of nutrition but also of oral health. This article discusses the connections between the influence of chewing function, salivation, and xerostomia on the health of the oral cavity of patients on long-term enteral and parenteral nutrition. In addition, the role of nurses in assessing oral health is presented as well as crucial elements of a comprehensive oral assessment in a nursing care plan. Patients receiving long-term enteral and parenteral nutrition have an increased risk of developing oral diseases. Increasing knowledge about the factors affecting oral health among nurses is crucial to provide appropriate care for patients requiring long-term nutritional treatment with omission of the natural route of food intake. Regular assessment of oral health by nurses should be an important aspect in long-term nutritional treatment recommendations

2'-O-Methylation of the second transcribed nucleotide within the mRNA 5' cap impacts the protein production level in a cell-specific manner and contributes to RNA immune evasion

In mammals, m7G-adjacent nucleotides undergo extensive modifications. Ribose of the first or first and second transcribed nucleotides can be subjected to 2'-O-methylation to form cap1 or cap2, respectively. When the first transcribed nucleotide is 2'-O-methylated adenosine, it can be additionally modified to N6,2'-O-dimethyladenosine (m6Am). Recently, the crucial role of cap1 in distinguishing between 'self' and 'non-self' in mammalian cells during viral infection was revealed. Here, we attempted to understand the impact of cap methylations on RNA-related processes. Therefore, we synthesized tetranucleotide cap analogues and used them for RNA capping during in vitro transcription. Using this tool, we found that 2'-O-methylation of the second transcribed nucleotide within the mRNA 5' cap influences protein production levels in a cell-specific manner. This modification can strongly hamper protein biosynthesis or have no influence on protein production levels, depending on the cell line. Interestingly, 2'-O-methylation of the second transcribed nucleotide and the presence of m6Am as the first transcribed nucleotide serve as determinants that define transcripts as 'self' and contribute to transcript escape from the host innate immune response. Additionally, cap methylation status does not influence transcript affinity towards translation initiation factor eIF4E or in vitro susceptibility to decapping by DCP2; however, we observe the resistance of cap2-RNA to DXO (decapping exoribonuclease)-mediated decapping and degradation.publishe

Identification and Evaluation of Potential SARS-CoV-2 Antiviral Agents Targeting mRNA Cap Guanine N7-Methyltransferase

SARS-CoV-2, the cause of the currently ongoing COVID-19 pandemic, encodes its own mRNA capping machinery. Insights into this capping system may provide new ideas for therapeutic interventions and drug discovery. In this work, we employ a previously developed Py-FLINT screening approach to study the inhibitory effects of compounds against the cap guanine N7-methyltransferase enzyme, which is involved in SARS-CoV-2 mRNA capping. We screened five commercially available libraries (7039 compounds in total) to identify 83 inhibitors with IC50 < 50 μM, which were further validated using RP HPLC and dot blot assays. Novel fluorescence anisotropy binding assays were developed to examine the targeted binding site. The inhibitor structures were analyzed for structure-activity relationships in order to define common structural patterns. Finally, the most potent inhibitors were tested for antiviral activity on SARS-CoV-2 in a cell based assay<br /

Fluorescence Anisotropy Assay with Guanine Nucleotides Provides Access to Functional Analysis of G alpha i1 Proteins

G alpha proteins as part of heterotrimeric G proteins are molecular switches essential for G protein-coupled receptor -mediated intracellular signaling. The role of the G alpha subunits has been examined for decades with various guanine nucleotides to elucidate the activation mechanism and G alpha protein-dependent signal transduction. Several approaches describe fluorescent ligands mimicking the GTP function, yet lack the efficient estimation of the proteins' GTP binding activity and the fraction of active protein. Herein, we report the development of a reliable fluorescence anisotropy-based method to determine the affinity of ligands at the GTP-binding site and to quantify the fraction of active G alpha i1 protein. An advanced bacterial expression protocol was applied to produce active human G alpha i1 protein, whose GTP binding capability was determined with novel fluorescently labeled guanine nucleotides acting as high-affinity G alpha i1 binders compared to the commonly used BODIPY FL GTP gamma S. This study thus contributes a new method for future investigations of the characterization of G alpha i and other G alpha protein subunits, exploring their corresponding signal transduction systems and potential for biomedical applications