Marine seaweeds synthesize a plethora of bioactive metabolites, of which phlorotannins of brown algae currently attract special attention due to their high antibiotic and cytotoxic capacities. Here we measured the minimum inhibitory concentrations (MICs) of several semi-purified phlorotannin preparations of different origins and molecular composition using a set of model unicellular organisms, such as Escherichia coli, Saccharomyces cerevisiae, Chlamydomonas reinhardtii, etc. For the first time, MIC values were evaluated for phlorotannin-enriched extracts of brown algae of the orders Ectocarpales and Desmarestiales. Phlorotannin extracts of Desmarestia aculeata, Fucus vesiculosus, and Ectocarpus siliculosus showed the lowest MIC values against most of the treated organisms (4–25 μg/mL for bacteria and yeast). Analysis of the survival curves of E. coli showed that massive loss of cells started after 3–4 h of exposure. Microalgae were less susceptible to activity of phlorotannin extracts, with the highest MIC values (≥200 µg/mL) measured for Chlorella vulgaris cells. D. aculeata, E. siliculosus, and three fucalean algae accumulate considerable amounts (4–16% of dry weight) of phlorotannins with MIC values similar to those widely used antibiotics. As these species grow abundantly in polar and temperate seas and have considerable biomass, they may be regarded as promising sources of phlorotannins.

The compact myelin sheath functions as an insulator for efficient conduction of nerve impulses. The formation of myelin sheaths around the axons of the most actively functioning neurons continues not only at the stage of brain development, but also in the process of learning and acquiring certain skills. Pathological or age-related disruption in myelin results in nerve conduction failure and neurodegeneration. Myelin Basic Protein (MBP) is the main constituent of the myelin sheath, representing about 30 % of the total myelin proteins in the central nervous system. Deletion in the MBP coding gene in mutant mice causes a severe neurological phenotype associated with rapid death of newborns. In this review, we discuss the current understanding of the role of the MBP protein in the formation of compact myelin and in neurodegeneration associated with demyelination.

Tailed dsDNA phages are ubiquitous and thought to infect almost any bacterial species. Escherichia coli HS – a commensal strain used as a model in gut colonization studies – has not been reported as a host for dsDNA phages and is resistant to more than 100 coliphages from the BASEL collection. Here, we report the first phages infecting E. coli HS, characterize their interaction with an endogenous BREX system, and provide a detailed genomic and phylogenetic description. Phages ϕHS1 ( Queuovirinae ) and ϕHS2 ( Ackermannviridae ) possess dPreQ₀ and 5- NeO mdU modifications that confer resistance to restriction digestion. ϕHS3 is a temperate phage, related to the native HS prophage ϕHS4, and represents a founding member of a novel genus ( Hueyvirus ) of P22-like phages capable of lateral transduction. We reveal exchange of tailspike genes between ϕHS2, ϕHS3, and Klebsiella -specific phages. Furthermore, we demonstrate that E. coli HS encodes a Klebsiella -like K47 capsule required for phage infection. These results suggest that the broad phage resistance of E. coli HS may be linked to its capsular type.

Bacteriophages are ubiquitous biological entities that profoundly influence microbiology research and biotechnology. Among coliphages, T1-like viruses (family Drexlerviridae) are notoriously known for their environmental stability and propensity to contaminate laboratory cultures and equipment. Despite this, the genomic features that may underlie their persistence and recurrent detection as laboratory contaminants remain insufficiently characterized. Here, we describe a novel T1-like bacteriophage, KanT1, identified as a recurrent contaminant emerging from environmental samples. Comparative genomics and phylogenetic analyses position KanT1 within the Tunavirus lineage, confirming its close relationship to canonical T1-like phages. Structure-informed annotation enabled the functional characterization of previously unannotated proteins, highlighting the importance of integrating structural predictions into phage genome analysis. Notably, we provide novel details regarding the distribution of superinfection exclusion cassette cor and identify an SH3 domain-containing protein associated with the lysis cassette. We show that SH3 is widespread, though non-universal, across Drexlerviridae genomes. Given the established role of SH3 domains as determinants of cell-wall binding specificity for endolysins of phages infecting Gram-positive bacteria, we propose that this protein represents an auxiliary component of the T1-like lysis module. Together, these findings expand the current understanding of T1-like phage genome organization and provide new insights into molecular features that may contribute to their broad host range and persistence in laboratory environments.