Publications by authors named "Knirel Y"

Bacteria from the genus are facultative human pathogens, primarily attacking the urinary tract and wounds. A total of 85 O serogroups have been identified so far among these bacilli. Bprz 86 was isolated from the fistula of a patient in Łódź, Poland.

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Naturally occurring human antibodies against glycans recognize and quickly eliminate infectious bacteria, viruses and aberrantly glycosylated neoplastic malignant cells, and they often initiate processes that involve the complement system. Using a printed glycan array (PGA) containing 605 glycoligands (oligo- and polysaccharides, glycopeptides), we examined which of the glycan-binding antibodies are able to activate the complement system. Using this PGA, the specificities of antibodies of the IgM and IgG classes were determined in the blood serum of healthy donors (suggested as mostly natural), and, then, using the same array, it was determined which types of the bound immunoglobulins were also showing C3 deposition.

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Article Synopsis
  • Capsular polysaccharide (CPS) from the bacterial pathogen Acinetobacter baumannii is a key factor in its virulence, specifically the KL58 variant produced by the strain MRSN 31468.
  • The CPS structure is characterized as a branched tetrasaccharide containing various sugar units, including glucose, galactose, N-acetyl-galactosamine, and a unique acid, indicating complex biosynthesis processes.
  • The study identified specific genes responsible for synthesizing components of CPS, noting that an acetyltransferase linked to a prophage may influence its structural modifications, while a related CPS variant contains a different epimer not present in MRSN 31468.
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Article Synopsis
  • Unlabelled infections are a key global problem, with antibiotic resistance and capsular polysaccharide (CPS) playing significant roles in their virulence.
  • A study identified an antibiotic-resistant isolate (48_n) from asymptomatic patients, revealing a unique CPS biosynthesis locus (KL71) and its structure using advanced spectroscopy techniques.
  • Understanding diverse antibiotic resistance profiles, particularly from less common bacterial lineages, could offer insights into resistance spread and the development of new therapeutic interventions.
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Capsular polysaccharide (CPS) is a heteroglycan that coats the cell surface of most isolates of the important Gram-negative bacterial pathogen, Acinetobacter baumannii. Strain MAR 15-4076, a clinical isolate recovered in Russia in 2015, was found to carry the KL129 sequence at the CPS biosynthesis K locus. The CPS was isolated from the strain and studied by sugar analysis, Smith degradation, one- and two-dimensional H and C NMR spectroscopy.

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The carbapenem-resistant isolate BAL062 is a clinical reference isolate used in several recent experimental studies. It is from a ventilator-associated pneumonia (VAP) patient in an intensive care unit at the Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam in 2009. Here, BAL062 was found to belong to the B sub-lineage of global clone 2 (GC2) isolates in the previously reported outbreak (2008 and 2012) of carbapenem-resistant VAP at the HTD.

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The structure of the K141 type capsular polysaccharide (CPS) produced by Acinetobacter baumannii KZ1106, a clinical isolate recovered from Kazakhstan in 2016, was established by sugar analyses and one- and two-dimensional H and C NMR spectroscopy. The CPS was shown to consist of branched tetrasaccharide repeating units (K-units) with the following structure: This structure was found to be consistent with the genetic content of the KL141 CPS biosynthesis gene cluster at the chromosomal K locus in the KZ1106 whole genome sequence. Assignment of the encoded enzymes allowed the first sugar of the K unit to be identified, which revealed that the β-d-GlcpNAc-(1→3)-d-GlcpNAc bond is the linkage between K-units formed by the Wzy polymerase.

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Two novel virulent phages of the genus infecting , a significant nosocomial pathogen, have been isolated and studied. Phages Brutus and Scipio were able to infect strains belonging to the K116 and K82 capsular types, respectively. The biological properties and genomic organization of the phages were characterized.

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The K239 type capsular polysaccharide (CPS) isolated from Acinetobacter baumannii isolate MAR19-4435 was studied by sugar analysis, one- and two-dimensional H and C NMR spectroscopy. K239 consists of branched heptasaccharide repeats (K-units) comprised of five residues of l-rhamnose (l-Rhap), and one residue each of d-glucuronic acid (d-GlcpA) and N-acetyl-d-glucosamine (d-GlcpNAc). The structure of K239 is closely related to that of the A.

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K63 capsular polysaccharide produced by Acinetobacter baumannii isolate LUH5551 (previously designated isolate O24) was re-examined using sugar analysis, Smith degradation, and one- and two-dimensional H and C NMR spectroscopy. Though previously reported as O24 consisting of linear tetrasaccharide units that include a 7-acetamido-5-acylamino form of 8-epilegionaminic acid [8eLeg5R7Ac, acylated at C5 with (S)-3-hydroxybutanoyl or acetyl (1:1)], the elucidated structure of the K63 type capsule was found to include a derivative of 5,7-diamino-3,5,7,9-tetradeoxy-d-glycero-d-galacto-non-2-ulosonic (legionaminic) acid, Leg5Ac7R, where R is either (S)-3-hydroxybutanoyl or an acetyl group (∼1:1 ratio). This finding is consistent with the presence of the lgaABCHIFG gene module for Leg5Ac7R biosynthesis in the KL63 gene cluster at the capsular polysaccharide (CPS) biosynthesis K locus in the LUH5551 genome.

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is a pathogen associated with various infection types, which often exhibits multiple antibiotic resistance. Phages, or bacterial viruses, have an ability to specifically target and destroy , offering a potential means of combatting multidrug-resistant infections. Phage enzymes are another promising therapeutic agent that can break down bacterial capsular polysaccharide, which shields from the immune response and external factors.

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Bacteriophage show promise for the treatment of infections that resist all therapeutically suitable antibiotics. Many tail-spike depolymerases encoded by phage that are able to degrade capsular polysaccharide (CPS) exhibit specificity for the linkage present between K-units that make up CPS polymers. This linkage is formed by a specific Wzy polymerase, and the ability to predict this linkage using sequence-based methods that identify the Wzy at the K locus could assist with the selection of phage for therapy.

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is a critical priority nosocomial pathogen that produces a variety of capsular polysaccharides (CPSs), the primary receptors for specific depolymerase-carrying phages. In this study, the tailspike depolymerases (TSDs) encoded in genomes of six novel Friunaviruses, APK09, APK14, APK16, APK86, APK127v, APK128, and one previously described phage, APK37.1, were characterized.

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The polysaccharide capsule surrounding bacterial cell plays an important role in pathogenesis of infections caused by the opportunistic pathogen Acinetobacter baumannii by providing protection from external factors. The structures of the capsular polysaccharide (CPS) produced by A. baumannii isolates and the corresponding CPS biosynthesis gene clusters are highly diverse, although many of them are related.

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Two closely related smooth strains, Kr1 and Ks20, were isolated from wound and skin samples, respectively, of two infected patients in central Poland. Serological tests, using the rabbit Kr1-specific antiserum, revealed that both strains presented the same O serotype. Their O antigens are unique among the O serotypes, which had been described earlier, as they were not recognized in an enzyme-linked immunosorbent assay (ELISA) by a set of O1-O83 antisera.

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The type of capsular polysaccharide (CPS) on the cell surface of Acinetobacter baumannii can determine the specificity of lytic bacteriophage under consideration for therapeutic use. Here, we report the isolation of a phage on an extensively antibiotic resistant ST2 A. baumannii isolate AB5001 that carries the KL3 CPS biosynthesis gene cluster predicting a K3-type CPS.

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Nonulosonic acids or non-2-ulosonic acids (NulOs) are an ancient family of 2-ketoaldonic acids (α-ketoaldonic acids) with a 9-carbon backbone. In nature, these monosaccharides occur either in a 3-deoxy form (referred to as "sialic acids") or in a 3,9-dideoxy "sialic-acid-like" form. The former sialic acids are most common in the deuterostome lineage, including vertebrates, and mimicked by some of their pathogens.

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Acinetobacter baumannii is an antibiotic-resistant opportunistic pathogen, one of the main causes of hospital infections. There is an urgent need for the development of therapy strategies which are not based on antibiotics. Hybridoma technology was used to obtain monoclonal antibodies.

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A structurally diverse capsular polysaccharide (CPS) in the outer cell envelope plays an important role in the virulence of the important bacterial pathogen, Acinetobacter baumannii. More than 75 different CPS structures have been determined for the species to date, and many CPSs include isomers of a higher sugar, namely 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acid. Recently, a novel isomer having the d-glycero-l-manno configuration (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) has been identified in the CPS from A.

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Novel, closely related phages Possum and Horatius infect , a phytopathogen causing soft rot in potatoes and other essential plants. Their properties and genomic composition define them as N4-like bacteriophages of the genus , a part of a recently formed family . It is proposed that the adsorption apparatus of these phages consists of tail fibers connected to the virion through an adapter protein.

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Bacteriophages and phage polysaccharide-degrading enzymes (depolymerases) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of bacteriophage KpV74 and phage depolymerase Dep_kpv74 specific to the hypervirulent Klebsiella pneumoniae of the K2 capsular type. The depolymerase Dep_kpv74 was identified as a specific glucosidase that cleaved the K2 type capsular polysaccharides of the K.

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The clonal bacterial species Acinetobacter baumannii is an emerging multidrug-resistant pathogen which causes high-lethality infections. Cells of A. baumannii are surrounded by the type-specific capsular polysaccharide (CPS), which provides resistance to the protective mechanisms of the host and is considered a target for immunization.

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Article Synopsis
  • The K98 capsular polysaccharide (CPS) from Acinetobacter baumannii clinical isolate REV-1184 was analyzed using various techniques, revealing its linear structure of tetrasaccharide repeats called K-units.
  • These K-units consist of four unique sugar residues, including d-GlcpNAc and d-GalpNAc, with the latter modified by a pyruvic acid acetal group.
  • Although K98 shares a similar composition with A. baumannii K4, the K98 CPS is linear while K4 is branched, attributed to differences in the Wzy polymerases responsible for their respective biosynthesis.
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Two acylated forms of the higher sugar, 5,7-diamino-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid called pseudaminic acid, Pse5Ac7Ac and Pse5Ac7RHb where R indicates (R)-3-hydroxybutanoyl, have been found to occur in many capsular polysaccharide (CPS) types produced by isolates of an important human pathogen, Acinetobacter baumannii. The presence of either a psaABCEDF or psaABCGHF gene module at the K locus (KL) for CPS biosynthesis determines the type of the variant produced. Here, an A.

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Acinetobacter baumannii isolate LUH5552 carries the KL89 capsule biosynthesis gene cluster. Capsular polysaccharide (CPS) isolated from LUH5552 was analyzed by sugar analysis, Smith degradation, and one- and two-dimensional H and C NMR spectroscopy. The K89 CPS structure has not been seen before in A.

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