Adam Vojtech

Bio: Adam Vojtech is an academic researcher. The author has contributed to research in topics: Analyte & Gene. The author has an hindex of 2, co-authored 5 publications receiving 180 citations.

Noteworthy Secondary Metabolites Naphthoquinones – their Occurrence, Pharmacological Properties and Analysis

Abstract: Chemical investigation of many bacterial and fungal, as well as plant species has revealed the presence of in- teresting compounds derived from naphthalene - 1,4-naphthoquinones and rarely also 1,2-naphthoquinones. They were detected in many species of families Bignoniaceae, Droseraceae, Plumbaginace, Boraginaceae, Juglandaceae as well as in species of small families, such as Dioncophyllaceae or Acanthaceae. Naphthoquinones have very interesting spectrum of biological actions, including antibiotic, antiviral, anti-inflammatory, antipyretic, antiproliferative and cytotoxic effects. Because of these properties the plants containing them are used in folk medicines, mainly by natives in Asia, where espe- cially Chinese medicine uses aerial as well as subterranean parts of these plants for hundreds years, and South America. The utilizing of naphthoquinones for medicinal purposes and their occurrence in nature is reviewed and discussed. Moreover, we review analytical techniques using for their analysis.

Effect of Nucleic Acid and Albumin on Luminescence Properties of Deposited TiO 2 Quantum Dots

Abstract: 1 Brno University of Technology, Faculty of Electrical Engineering and Communication, Department of Microelectronics, Technicka 3058/10, 616 00 Brno, Czech Republic 2 Mendel University in Brno, Faculty of Agronomy, Department of Chemistry and Biochemistry, Zemedelska 1, 613 00 Brno, Czech Republic 3 Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, 616 00 Brno, Czech Republic 4 Brno University of Technology, Faculty of Chemistry, Institute of Physical and Applied Chemistry, Purkynova 118, 612 00 Brno, Czech Republic * E-mail: drbohla@feec.vutbr.cz

Single-cell transcriptomics of neuroblastoma identifies chemoresistance-associated genes and pathways

Abstract: High-Risk neuroblastoma (NB) survival rate is still <50%, despite treatments being more and more aggressive. The biggest hurdle liable to cancer therapy failure is the drug resistance by tumor cells that is likely due to the intra-tumor heterogeneity (ITH). To investigate the link between ITH and therapy resistance in NB, we performed a single cell RNA sequencing (scRNAseq) of etoposide and cisplatin resistant NB and their parental cells. Our analysis showed a clear separation of resistant and parental cells for both conditions by identifying 8 distinct tumor clusters in etoposide-resistant/parental and 7 in cisplatin-resistant/parental cells. We discovered that drug resistance can affect NB cell identities; highlighting the bi-directional ability of adrenergic-to-mesenchymal transition of NB cells. The biological processes driving the identified resistant cell subpopulations revealed genes such as (BARD1, BRCA1, PARP1, HISTH1 axis, members of RPL family), suggesting a potential drug resistance due to the acquisition of DNA repair mechanisms and to the modification of the drug targets. Deconvolution analysis of bulk RNAseq data from 498 tumors with cell subpopulation signatures showed that the transcriptional heterogeneity of our cellular models reflected the ITH of NB tumors and allowed the identification of clusters associated with worse/better survival. Our study demonstrates the distinct cell populations characterized by genes involved in different biological processes can have a role in NB drug treatment failure. These findings evidence the importance of ITH in NB drug resistance studies and the chance that scRNA-seq analysis offers in the identification of genes and pathways liable for drug resistance.

PREPARATION AND ANTIMICROBIAL ACTIVITY OF NUCLEOBASE-CONJUGATED CdTe/ZnSe CORE/SHELL QUANTUM DOTS

Abstract: Inorganic nanomaterials have large specific surface area and high bioactivity which made them promising alternatives to the traditional organic antimicrobial agents that are extremely irritant and toxic. In the present report, CdTe/ZnSe core/shell quantum dots (QDs) were conjugated with different nucleobases and their antibacterial activity against Escherichia coli was investigated. The CdTe/ZnSe core/shell QDs were synthesized in a green way or environment-friendly way using water as a solvent instead of organic solvents. They were successfully conjugated with different nucleobases and were characterized using fluorescence and absorbance spectrophotometry and dynamic light scattering techniques. The antimicrobial activity of all the samples along with control (bare QDs) was checked on E. coli, a commonly used bacterial model species in microbiology research. Almost all nucleobases showed good antibacterial activity comparing to control probably forming excess ROS which can disturb different metabolisms in bacterial cell. Guanine showed the best result among all other nucleobases.

Phenolic Compounds: Introduction

Abstract: “Plant phenolics” and “polyphenols” are secondary natural metabolites arising biogenetically fromeitherthe shikimate/phenylpropanoid pathway,which directly provides phenylpropanoids, or the “polyketide” acetate/malonate pathway, which can produce simple phenols, or both, thus producing monomeric and polymeric phenols and polyphenols, which fulfill a very broad range of physiological roles in plants. Higher plants synthesize several thousand known different phenolic compounds. The ability to synthesize phenolic compounds has been selected throughout the course of evolution in different plant lineages, thus permitting plants to cope with the constantly changing environmental challenges over evolutionary time. Plant phenolics are considered to have a key role as defense compounds when environmental stresses, such as high light, low temperatures, pathogen infection, herbivores, and nutrient deficiency, can lead to an increased production of free radicals and other oxidative species in plants. Both biotic and abiotic stresses stimulate carbon fluxes from the primary to the secondary metabolic pathways,

Biosynthesis and molecular actions of specialized 1,4-naphthoquinone natural products produced by horticultural plants.

Abstract: The 1,4-naphthoquinones (1,4-NQs) are a diverse group of natural products found in every kingdom of life. Plants, including many horticultural species, collectively synthesize hundreds of specialized 1,4-NQs with ecological roles in plant-plant (allelopathy), plant-insect and plant-microbe interactions. Numerous horticultural plants producing 1,4-NQs have also served as sources of traditional medicines for hundreds of years. As a result, horticultural species have been at the forefront of many basic studies conducted to understand the metabolism and function of specialized plant 1,4-NQs. Several 1,4-NQ natural products derived from horticultural plants have also emerged as promising scaffolds for developing new drugs. In this review, the current understanding of the core metabolic pathways leading to plant 1,4-NQs is provided with additional emphasis on downstream natural products originating from horticultural species. An overview on the biochemical mechanisms of action, both from an ecological and pharmacological perspective, of 1,4-NQs derived from horticultural plants is also provided. In addition, future directions for improving basic knowledge about plant 1,4-NQ metabolism are discussed.