Patrycja Bielańska

The taxonomic classification of actinomycete strain, designated as 5.8^T, extracted from the moonmilk which was collected in cave of Szczelina Chochołowska, in the Tatra National Park in Poland, was determined using a polyphasic taxonomy. The pairwise comparisons of the 16 S rRNA gene sequences revealed that the strain belongs to the genus Streptomyces, sharing 100% similarity with Streptomyces stoeckheimensis DSM 116496ᵀ and Streptomyces tritrimontium DSM 119353^T. The digital DNA–DNA hybridization and average nucleotide identity values between strain 5.8^T and the type strains of S. stoeckheimensis and S. tritrimontium were found to be 47.70 and 36.7%, and 93.40 and 90.25%, respectively, showing that strain 5.8^T represents a novel species of the genus Streptomyces. Consequently, it is proposed that strain 5.8^T be assigned to the genus Streptomyces as Streptomyces tatrensis sp. nov. with strain 5.8^T (= DSM 119354^T = PCM 3549^T) as the type strain. Genome-mining revealed presence of high number of biosynthetic gene clusters and stress related genes in the strain.

Mucopolysaccharidoses (MPS) are rare genetic disorders belonging to the lysosomal storage diseases. They are caused by mutations in genes encoding lysosomal enzymes responsible for degrading glycosaminoglycans (GAGs). As a result, GAGs accumulate in lysosomes, leading to impairment of cells, organs and, consequently, the entire body. Many of the therapies proposed thus far require the participation of chaperone proteins, regardless of whether they are therapies in common use (enzyme replacement therapy) or remain in the experimental phase (gene therapy, STOP-codon-readthrough therapy). Chaperones, which include heat shock proteins, are responsible for the correct folding of other proteins to the most energetically favorable conformation. Without their appropriate levels and activities, the correct folding of the lysosomal enzyme, whether supplied from outside or synthesized in the cell, would be impossible. However, the baseline level of nonspecific chaperone proteins in MPS has never been studied. Therefore, the purpose of this work was to determine the basal levels of nonspecific chaperone proteins of the Hsp family in MPS cells and to study the effect of normalizing GAG concentrations on these levels. Results of experiments with fibroblasts taken from patients with MPS types I, II, IIIA, IIIB, IIIC, IID, IVA, IVB, VI, VII, and IX, as well as from the brains of MPS I mice (Idua^−/−), indicated significantly reduced levels of the two chaperones, Hsp70 and Hsp40. Interestingly, the reduction in GAG levels in the aforementioned cells did not lead to normalization of the levels of these chaperones but caused only a slight increase in the levels of Hsp40. An additional transcriptomic analysis of MPS cells indicated that the expression of other genes involved in protein folding processes and the cell response to endoplasmic reticulum stress, resulting from the appearance of abnormally folded proteins, was also modulated. To summarize, reduced levels of chaperones may be an additional cause of the low activity or inactivity of lysosomal enzymes in MPS. Moreover, this may point to causes of treatment failure where the correct structure of the enzyme supplied or synthesized in the cell is crucial to lower GAG levels.

The “antibiotic crisis”, defined as the appearance of microbial strains resistant to most, if not all, already known antibiotics, indicates that searching for previously unknown antimicrobial agents is crucial for further development of novel drugs that can be used to combat infections caused by bacteria and fungi. Bacteria living in untypical and extreme habitats appear to be a potentially reached source of such compounds. We recently reported an isolation of newly identified strains of Actinobacteria from the Szczelina Chochołowska cave (Tatra Mountains, Poland). Some of them produced molecules revealing antibacterial, antifungal and anticancer properties. Here, we describe further characterization of the selected strains. Their microbiological properties, ability to form biofilms and antimicrobial activities against various strains of bacteria and fungi are reported. The selected strains of newly isolated Actinobacteria belonging to the genus Streptomyces appear a promising source of previously unknown antimicrobial agents.

Resistance of bacteria, fungi and cancer cells to antibiotics and other drugs is recognized as one of the major problems in current medicine. Therefore, a search for new biologically active compounds able to either kill pathogenic cells or inhibit their growth is mandatory. Hard-to-reach habitats appear to be unexplored sources of microorganisms producing previously unknown antibiotics and other molecules revealing potentially therapeutic properties. Caves belong to such habitats, and Actinobacteria are a predominant group of microorganisms occurring there. This group of bacteria are known for production of many antibiotics and other bioactive compounds. Interestingly, it was demonstrated previously that infection with bacteriophages might enhance production of antibiotics by them. Here, we describe a series of newly isolated strains of Actinobacteria that were found in caves from the Tatra Mountains (Poland). Phage induction tests indicated that some of them may bear active prophages able to produce virions upon treatment with mitomycin C or UV irradiation. Among all the examined bacteria, two newly isolated Streptomyces sp. strains were further characterized to demonstrate their ability to inhibit the growth of pathogenic bacteria (strains of Staphylococcus aureus, Salmonella enterica, Enterococcus sp., Escherichia coli, and Pseudomonas aeruginosa) and fungi (different species and strains from the genus Candida). Moreover, extracts from these Streptomyces strains reduced viability of the breast-cancer cell line T47D. Chemical analyses of these extracts indicated the presence of isomers of dichloranthrabenzoxocinone and 4,10- or 10,12-dichloro-3-O-methylanthrabenzoxocinone, which are putative antimicrobial compounds. Moreover, various previously unknown (unclassified) molecules were also detected using liquid chromatography–mass spectrometry, suggesting that tested Streptomyces strains may synthesize a battery of bioactive compounds with antibacterial, antifungal, and anticancer activities. These results indicate that further studies on the newly isolated Actinobacteria might be a promising approach to develop novel antibacterial, antifungal, and/or anticancer drugs.

Leczenie chorób neurodegeneracyjnych, schorzeń charakteryzujących się postępującą utratą komórek nerwowych, stanowi ogromne wyzwanie współczesnej medycyny. Poszukiwanie leków na te choroby trwa w wielu laboratoriach na świecie. Do dnia dzisiejszego zaproponowano kilka strategii terapeutycznych, które nie wykazują jednak wystarczającej skuteczności albo są jeszcze na wczesnym etapie badań przedklinicznych. Jednym z najnowszych podejść do terapii jest przyspieszona degradacja agregatów białkowych, które stanowią przyczynę aż 70% tych schorzeń. Procesem, który mógłby zostać wykorzystany w tym celu jest autofagia czyli lizosomalna degradacja makrocząsteczek która odpowiednio zaindukowana mogłaby doprowadzić do takiego efektu. Poszukiwania związku, który nie tylko aktywowałby autofagię ale był także bezpieczny w długoterminowym stosowaniu oraz przekraczał barierę krew-mózg doprowadziły do badań nad jednym z flawonoidów, genisteiną, którego szczególnie duże stężenia można znaleźć w soi. Badania przeprowadzone nad tym flawonoidem wskazały jego niezwykłą skuteczność w usuwaniu agregatów białkowych tworzonych przez β-amyloid i hiperfosforylowaną formę białka tau, a także zmutowaną huntingtynę. Co więcej, u zwierząt będących modelami tych chorób wskazano na całkowite zniesienie kognitywnych i motorycznych objawów. Z uwagi na wysokie bezpieczeństwo stosowania genisteiny oraz fakt, że przekracza ona barierę krew-mózg, izoflawon ten jest kandydatem na skuteczny lek w leczeniu nie tylko choroby Alzheimera i Huntingtona ale także innych chorób spowodowanych agregacją białek. W manuskrypcie przedstawiono najnowsze dane dotyczące badań nad zastosowaniem genisteiny w modelach chorób neurodegeneracyjnych ze szczególnym naciskiem na jej działanie zależne od procesu autofagii.

A direct link between DNA replication regulation and central carbon metabolism (CCM) has been previously demonstrated in Bacillus subtilis and Escherichia coli, as effects of certain mutations in genes coding for replication proteins could be specifically suppressed by particular mutations in genes encoding CCM enzymes. However, specific molecular mechanism(s) of this link remained unknown. In this report, we demonstrate that various CCM metabolites can suppress the effects of mutations in different replication genes of E. coli on bacterial growth, cell morphology, and nucleoid localization. This provides evidence that the CCM-replication link is mediated by metabolites rather than direct protein-protein interactions. On the other hand, action of metabolites on DNA replication appears indirect rather than based on direct influence on the replication machinery, as rate of DNA synthesis could not be corrected by metabolites in short-term experiments. This corroborates the recent discovery that in B. subtilis, there are multiple links connecting CCM to DNA replication initiation and elongation. Therefore, one may suggest that although different in detail, the molecular mechanisms of CCM-dependent regulation of DNA replication are similar in E. coli and B. subtilis, making this regulation an important and common constituent of the control of cell physiology in bacteria.