Complete Genome Sequences of Streptomyces albus Strain INA 01303.

Here, we report the complete genome sequence of Streptomyces albus strain INA 01303, which was isolated from the Salt Lake Tambukan (Russia). The genome consists of a linear 6,840,896-nucleotide chromosome. This strain is predicted to produce a range of novel secondary metabolites with antibiotic activity.

Draft Genome Sequence of Pseudomonas brassicacearum Strain UTMN3, a Biological Control Agent from the Rhizosphere of Pisum sativum.

Here, we announce and describe the draft genome sequence of Pseudomonas brassicacearum UTMN3, which contains 40 contigs comprising 6,658,810 bp, with a GC content of 60.9%. The genome contains 5,825 protein-coding genes and 65 RNA-coding genes. The genome of UTMN3 contains several genes that are likely contributors to plant protection.

Draft Genome Sequence of the Multiple Antibiotic Producer Bacillus velezensis X-BIO-1.

Here, we describe the draft genome sequence of Bacillus velezensis strain X-BIO-1, which contains 16 contigs, comprising 3,861,135 bp with a G+C content of 46.54%. The annotated draft genome contains 3,710 protein-coding genes and 62 RNA genes. We identified genes responsible for the synthesis of various antibiotics.

A Low-Molecular-Weight Compound Derived from Human Leukocytes Determines a Bactericidal Activity of the Interferon Preparation.

The aim of this study was to characterize the structure and mode of action of antimicrobials derived from a commercial preparation of alfa-interferon. By combination of semi-preparative/analytical reversed-phase high-performance liquid chromatography, we isolated and purified a novel active substance based on carbohydrate with a complex of amino acids, which determines antimicrobial property of commercial preparation of interferon. A size-exclusion chromatography was performed and LC/ESI-MS revealed molecular masses of active substance were in the range of 180-249 Da. Edman sequencing identified phenylthiohydantoin (PTH) derivatives which consisted a set of preliminary (Asp, Glu, Gly, and Ala) and minor amino acids (Leu and Thr) at equimolar ratio. Thus, the purified active substance is a compound containing the complex of amino acids connected with carbohydrate background and called leucidin. Leucidin demonstrated antimicrobial activity against the model Escherichia coli (E. coli) K12 strain at a minimal inhibitory concentration of 20 µg mL-1. The revealed antimicrobial mechanism of action is associated with violation of the bacterial cell wall leading to a SOS response and bacterial autolysis. Despite the preliminary nature of the results, obtained data allowed us to discover the previously unknown leukocyte-derived antimicrobial molecules.

A Novel High-Molecular-Mass Bacteriocin Produced by Enterococcus faecium: Biochemical Features and Mode of Action.

Discovery of a novel bacteriocin is always an event in sciences, since cultivation of most bacterial species is a general problem in microbiology. This statement is reflected by the fact that number of bacteriocins is smaller for tenfold comparing to known antimicrobial peptides. We cultivated Enterococcus faecium on simplified medium to reduce amount of purification steps. This approach allows to purify the novel heavy weight bacteriocin produced by E. faecium ICIS 7. The novelty of this bacteriocin, named enterocin-7, was confirmed by N-terminal sequencing and by comparing the structural-functional properties with available data. Purified enterocin-7 is characterized by a sequence of amino acid residues having no homology in UniProt/SwissProt/TrEMBL databases: NH2 - Asp - Ala - His - Leu - Ser - Glu - Val - Ala - Glu - Arg - Phe - Glu - Asp - Leu - Gly. Isolated thermostable protein has a molecular mass of 65 kDa, which allows it to be classified into class III in bacteriocin classification schemes. Enterocin-7 displayed a broad spectrum of activity against some Gram-positive and Gram-negative microorganisms. Fluorescent microscopy and spectroscopy showed the permeabilizing mechanism of the action of enterocin-7, which is realized within a few minutes.

Antimicrobial activity of the indolicidin-derived novel synthetic peptide In-58.

Natural peptides with antimicrobial activity are extremely diverse, and peptide synthesis technologies make it possible to significantly improve their properties for specific tasks. Here, we investigate the biological properties of the natural peptide indolicidin and the indolicidin-derived novel synthetic peptide In-58. In-58 was generated by replacing all tryptophan residues on phenylalanine in D-configuration; the α-amino group in the main chain also was modified by unsaturated fatty acid. Compared with indolicidin, In-58 is more bactericidal, more resistant to proteinase K, and less toxic to mammalian cells. Using molecular physics approaches, we characterized the action of In-58 on bacterial cells at the cellular level. Also, we have found that studied peptides damage bacterial membranes. Using the Escherichia coli luminescent biosensor strain MG1655 (pcolD'::lux), we investigated the action of indolicidin and In-58 at the subcellular level. At subinhibitory concentrations, indolicidin and In-58 induced an SOS response. Our data suggest that indolicidin damages the DNA, but bacterial membrane perturbation is its principal mode of action. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Novel haemoglobin-derived antimicrobial peptides from chicken (Gallus gallus) blood: purification, structural aspects and biological activity.

AIM: To purify and characterize antimicrobial peptides derived from the acid extract of Gallus gallus blood cells. METHODS AND RESULTS: Two polypeptides (i.e. CHb-1 and CHb-2) with antibacterial activity were detected in the acidic extract of blood cells from chicken (G. gallus). The isolated peptides that possessed a potent antibacterial activity were purified using a two-step chromatography procedure that involved solid-phase extraction of a total protein/peptide extract followed by thin fractionation by reversed-phase high performance liquid chromatography (RP-HPLC). The molecular masses of the purified peptides were similar and were 4824·4 and 4825·2 Da, which have been measured by matrix-assisted laser desorption/ionization mass spectrometry (MALDI TOF MS). Their amino acid sequences were determined by Edman degradation and showed that the peptides were fully identical to the two fragments of G. gallus α-haemoglobin localized into different subunits (A and D respectively). The peptides were active in micromolar concentrations against Gram-negative Escherichia coli K12 TG1. Using the 1-N-phenylnaphthylamine, the FITC-dextran labelled probes and the live/dead staining allowed to show the hemocidin mode of action and estimate the pore size. CONCLUSION: In this study, for the first time, α-haemoglobin from chicken (G. gallus) has been investigated as a donor of the two high homologous native peptide fragments that possess potent antibacterial activity in vitro. These are membrane-active peptides and their mechanism of action against E. coli involves a toroidal pore formation. SIGNIFICANCE AND IMPACT OF THE STUDY: The obtained results expand the perception of the role of haemoglobin in a living system, describing it as a source of multifunction substances. Additionally, the data presented in this paper may contribute to the development of new, cost-effective, antimicrobial agents.

[BIOLOGICAL ACTIVITY OF ANTIMICROBIAL PEPTIDES FROM CHICKENS THROMBOCYTES].

AIM: Isolation and study of biological activity of antimicrobial peptides from chickens thrombocytes. MATERIALS AND METHODS: Peptides from chickens thrombocytes, obtained by reverse-phase high-performance liquid chromatography method with stepped and linear gradients of concentration increase of the organic solvent were used in the study. Their antimicrobial activity was determined by microtitration method in broth; mechanism of biological effect--by using fluorescent spectroscopy method with DNA-tropic dyes. RESULTS: Individual fractions of peptides were isolated from chickens thrombocytes, that possess antimicrobial activity against Staphylococcus aureus P209 and Escherichia coli K12. A disruption of integrity of barrier structures of microorganisms under the effect of thrombocyte antimicrobial peptides and predominance of cells with damaged membrane in the population of E. coli was established. CONCLUSION: The data obtained on antimicrobial activity and mechanism of bactericidal effect of the peptide fractions from chickens thrombocytes isolated for the first time expand the understanding of functional properties of chickens thrombocytes and open a perspective for their further study with the aim of use as antimicrobial means.

[BIOLOGICAL ACTIVITY OF ANTIMICROBIAL PEPTIDES OF ENTEROCOCCUS FAECIUM].

AIM: Isolate bacteriocins from Enterococcus faecium metabolites and characterize their effect on cells of Gram positive (Listeria monocytogenes) and Gram negative (Escherichia coli) bacteria. MATERIALS AND METHODS: Methods of solid-phase extraction, ion-exchange and reversed phase chromatography were applied for isolation of bacteriocins from cultural medium of bacteria MALDI time-of-flight mass-spectrometry was used for characterization of the obtained preparations. The mechanism of biological effect of peptides was evaluated using DNA-tropic dyes (SYTO 9 and PI) with subsequent registration of fluorescence spectra: Atomic-force microscopy (AFM) was used for characterization of morpho-functional reaction of target cells. RESULTS: Peptide fractions with mass of 1.0 - 3.0 kDa were isolated from enterococci metabolites, that inhibit the growth of indicator microorganisms. E. faecium strain exoproducts were shown to increase membrane permeability during interaction with L. monocytogenes, that results in subsequent detectable disturbance of normal cell morphology of listeria. Alterations of E. coli surface during the effect of purified peptide fraction was detected using AFM. CONCLUSION: The studies carried out have revealed the effect of bacteriocins of enterococci on microorganisms with various types of cell wall composition and have confirmed the importance of bacterial barrier structure permeability disturbance in the mechanism of antimicrobial effect of enterocins.

[Cycloferon biological activity characteristics].

AIM: Study the effect of cycloferon in experimental and clinical conditions on persistence properties of aurococci as well as features of their morpho-functional reaction by atomic force microscopy. MATERIALS AND METHODS: The study was carried out in 12 Staphylococcus aureus clones isolated from mucous membrane of nose anterior part of a resident carrier. The effect of cycloferon in vivo was evaluated in 26 resident staphylococci carriers under the control of anti-carnosine activity of staphylococci. Anti-carnosine activity was determined by O.V. Bukharin et al. (1999), biofilm formation -by G.A. O'Toole et al. (2000). Staphylococci treated with cycloferon were studied by atomic force microscopy in contact mode using scanning probe SMM-2000 microscope. RESULTS: The decrease of persistence properties of staphylococci under the effect of cycloferon in vitro and in vivo may be examined as one of the mechanisms of biological activity of the preparation. A significant increase of S. aureus surface roughness and changes in their morphology under the effect of cycloferon allow stating the disorder of barrier functions in the aurococci cell wall. CONCLUSION: The data obtained expand the understanding of cycloferon biological activity mechanisms.