Biology subjects

Kardava, K.

Publications and source records attributed to Kardava, K..

3 recordsLinked to original sources

bioRxiv2024

Universal Receptive System as a novel regulator of transcriptomic activity of Staphylococcus aureus

Our previous studies revealed the existence of a Universal Receptive System that regulates interactions between cells and their environment. This system is composed of DNA- and RNA-based Teazeled receptors (TezRs) found on the surface of prokaryotic and eukaryotic cells, as well as integrases and recombinases.. In the current study, we aimed to provide further insight into the regulatory role of TezR and its loss in Staphylococcus aureus gene transcription. To this end, transcriptomic analysis of S. aureus MSSA VT209 was performed following the destruction of TezRs. Bacterial RNA samples were extracted from nuclease-treated and untreated S. aureus MSSA VT209. After destruction of the DNA-based-, RNA-, or combined DNA- and RNA-based TezRs of S. aureus, 103, 150, and 93 genes were significantly differently expressed, respectively. The analysis revealed differential clustering of gene expression following the loss of different TezRs, highlighting individual cellular responses following the loss of DNA- and RNA-based TezRs. KEGG pathway gene enrichment analysis revealed that the most upregulated pathways following TezR inactivation included those related to energy metabolism, cell wall metabolism, and secretion systems. Some of the genetic pathways were related to the inhibition of biofilm formation and increased antibiotic resistance, and we confirmed this at the phenotypic level using in vitro studies. The results of this study add another line of evidence that the Universal Receptive System plays an important role in cell regulation, including cell responses to the environmental factors of clinically important pathogens, and that nucleic acid-based TezRs are functionally active parts of the extrabiome.

microbiology↗

bioRxiv2024

Previously unknown regulatory role of extracellular RNA on bacterial directional migration

Bacterial directional migration plays a significant role in bacterial adaptation. However, the regulation of this process, particularly in young biofilms, remains unclear. Here, we demonstrated the critical role of extracellular RNA as part of the Universal Receptive System in bacterial directional migration using a multidisciplinary approach, including bacterial culture, biochemistry, and genetics. We found that the destruction or inactivation of extracellular RNA with RNase or RNA-specific antibodies in the presence of the chemoattractant triggered the formation of bacterial "runner cells>> in what we call a "panic state" capable of directional migration. These cells quickly migrated even on the surface of 1.5% agar and formed evolved colonies that were transcriptionally and biochemically different from the ancestral cells. We have also shown that cell-free DNA from blood plasma can act as a potent bacterial chemoattractant. Our data revealed a previously unknown role of bacterial extracellular RNA in the regulation of bacterial migration and have shown that its destruction or inhibition triggered the directional migration of developing and mature biofilms towards the chemoattractant.

microbiology↗

bioRxiv2023

Antifungal activity of the novel compound M451 against phytopathogens

Phytopathogenic fungi are the dominant causal agents of plant diseases. Currently available fungicides have significant disadvantages, being insufficiently effective owing to both intrinsic tolerance and the spread of antibiotic resistance accumulating in plant tissues, posing a global threat to public health. Finding a new broad-spectrum fungicide is a challenge for plant protection. We studied the potency of a novel antimicrobial agent, M451, against different phytopathogenic fungi of the phyla Ascomycota, Oomycota, and Basidiomycota. M451 exhibited significant antifungal activity with EC50 values ranging from 34 to 145 {micro}g/mL. Analysis of the minimal fungicidal concentration and conidial destruction assay revealed that M451 possesses the highest activity compared with different polyene, azole, and phenylpyrrole antifungals against Fusarium oxysporum. Time-kill analysis revealed that M451 was the only antifungal agent tested that exhibited antifungal activity within 5 min of exposure. Spore production and germination were also significantly inhibited by M451 treatment. Based on the broad spectrum of antifungal effects across different plant pathogens, M451 could be a new chemical fungicide for plant disease management.

microbiology↗