The structure of capsular polysaccharide (CPS) classified to K166 of Acinetobacter baumannii MAR 21-5059 strain was established using component analyses as well as 1H and 13C NMR spectroscopy, including two-dimensional homonuclear 1Н,1Н COSY, TOCSY, ROESY and heteronuclear 1Н,13C HSQC, HMBC, HSQC-TOCSY and HSQC-NOESY experiments. The CPS is composed of branched tetrasaccharide K-units containing two d-GlcNAc residues, one d-Gal and rarely occurred residue, l-RhaNAc3NAc. The following structure of the repeating K-unit was established: To our knowledge the СPS structure is novel and has not been previously published. Functions of genes in the KL166 locus of A. baumannii MAR 21-5059 were assigned by a comparison with sequences in the available databases and found to be in agreement with the CPS structure.

Klebsiella pneumoniae is a significant pathogen responsible for a range of infections, including pneumonia, urinary tract infections, and sepsis, in both human and veterinary medicine. The extracellular polysaccharide produced by this bacterium forms a capsule that protects the cell from immune responses and external influences, complicating treatment. The World Health Organization has placed this pathogen into the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) of pathogens that require special attention due to their resistance to multiple drugs, and hypermucoid K. pneumoniae strains with prevalent capsular types (e.g., K1 and K2) have been extensively studied. However, rare capsular types that are less well-characterised can still pose significant challenges. In the present study, we isolated a K. pneumoniae strain with capsular type K14, which is associated with antibiotic-resistant urogenital infections in felines, from a veterinary clinic. We successfully isolated and characterised three bacteriophages that exhibit rapid adsorption to and efficient lysis of the bacterium. All three phages demonstrated strictly lytic behavior and proved effective in degrading the extracellular polysaccharide capsule of the pathogen. We have modelled the receptor-binding proteins of these phages, which exhibit depolymerising activity. These proteins were produced in recombinant form, and experimental evidence has demonstrated their capacity to cleave the polysaccharide associated with the K14 capsular type. Furthermore, the chemical structure of the resulting cleavage products was determined. All three phages have been thoroughly characterised and show potential for application in combating multidrug-resistant K. pneumoniae.

Matrix and cell wall polysaccharides of Micrococcus luteus HB3.2.1 were obtained. The following structures of the glycopolymers were established by compositional analysis and 1D and 2D NMR spectroscopy: →4)-ɑ-d-GalpNAc-(1→2)-l-2HO-Glt-(5→2)-d-Asn-(1→4)-ɑ-d-QuipNAc4N-(1→ PSI. where d-Asn indicates d-asparagine, l-2HO-Glt - l-2-hydroxy-glutaric acid. →2)-ɑ-d-Manp-(1→3)-ɑ-d-Manp-(1→6)-ɑ-d-Manp-(1→ PSII. →6)-ɑ-d-Glcp-(1→4)-β-d-ManpNAcA-(1→ PSIII. →6)-ɑ-d-Glcp-(1→4)-β-d-GlcpNAc3NAcA-(1→ PSIV. The structure of the PSI is unique among the bacterial polysaccharides. It is including non-sugar residues such as d-asparagine andl-2-hydroxy-glutaric acid in the main chain. The matrix polysaccharide (PSI) possesses a cytotoxic activity.

Background/Objectives: Breast cancer remains one of the most prevalent and life-threatening malignancies worldwide. This study describes the design and biological evaluation of a series of secosteroid-2-pyrazoline hybrids as novel antitumor agents against ERα-positive breast cancer cell lines MCF-7 and T47D. Methods: A simple and efficient method for synthesizing secosteroid-2-pyrazoline hybrids was developed starting from 13α-hydroxy-3-methoxy-13,17-secoestra-1,3,5(10)-triene-17-oic acid hydrazide and 1,3-diketones. The resulting secosteroid derivatives were evaluated against hormone-dependent MCF-7 and T47D breast cancer cells. Furthermore, the selectivity and effects of three lead compounds on signaling pathways in MCF-7 cells were examined. Flow cytometry was used to assess the cell-cycle distribution of MCF-7 cells treated with the lead compound. Results: Among the synthesized hybrids, compounds 3f, 3j, and 3k exhibited potent antiproliferative activity with IC50 values of 0.2-0.5 μM against breast cancer cells, while demonstrating very low cytotoxicity towards normal cells (IC50 > 25 μM), indicating a favorable safety profile. The antitumor activity of lead compound 3j was additionally investigated in combination with standard chemotherapeutics, docetaxel and doxorubicin, yielding synergistic effects. The lead compounds showed a dual mechanism of action by inhibiting S6 kinase and promoting Bcl-2 phosphorylation at 0.9 μM, without significantly affecting hormonal breast cancer targets such as ERα, GREB1, and AR. Compound 3j induced apoptosis accompanied by a reduction of the G1/G0 phase in MCF-7 cells. Conclusions: These findings highlight secosteroid-2-pyrazoline hybrids as promising candidates for the development of next-generation breast cancer therapeutics targeting apoptosis and S6K signaling pathways.

Capsular polysaccharide (CPS), a heteropolymeric carbohydrate structure present on the cell surface of most isolates of the bacterial pathogen Acinetobacter baumannii, is a major virulence determinant. Here, the CPS produced by A. baumannii MRSN 31468, which carries the KL58 CPS biosynthesis locus, was studied by sugar analysis, one- and two-dimensional 1H and 13C NMR spectroscopy. The structure was found to consist of a repeating tetrasaccharide K-unit that includes glucose (D-Glcp), galactose (D-Galp), N-acetyl-galactosamine (D-GalpNAc), and 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (5,7-di-N-acetylpseudaminic acid; Pse5Ac7Ac). The CPS has a branched repeating unit with the disaccharide →3)-β-D-Glc-(1→3)-β-D-GalNAc-(1→ as the mainchain and O-6 of the Glc unit substituted with the disaccharide β-Pse5Ac7Ac-(2→6)-α-D-Gal, and Pse5Ac7Ac is partially acetylated at O-4. The presence of Pse5Ac7Ac in the K58 structure is consistent with the presence of psaA-F genes in KL58, which are responsible for Pse5Ac7Ac synthesis. 4-O-acetylation of Pse5Ac7Ac was traced to an acetyltransferase, Atr44, which was found to be closely related to Atr29 that similarly decorates Pse5Ac7Ac with 4OAc in the K46-type CPS. Atr44 like Atr29 is encoded by a gene found in a prophage. The K58 CPS produced by MRSN 31468 did not include the 8-epimer of Pse5Ac7Ac (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) found in the closely related CPS from BAL062 that also carries KL58. Hence, the gene(s) for conversion of Pse5Ac7Ac to 8ePse5Ac7Ac must lie elsewhere.

A method for the synthesis of acetyl derivatives of spiro-1,3,4-thiadiazolines was developed involving a catalytic reaction of cyclic ketones with oxamic acid thiohydrazides in the presence of TsOH followed by acetylation.

Lipopolysaccharide was extracted with hot aqueous phenol from cells of Azospirillum himalayense ptl-3T, a diazotrophic Gram-negative bacterium isolated from Himalayan valley soil, India. The O-polysaccharide (OPS) was released by mild acid hydrolysis of the lipopolysaccharide and was structurally characterized by chemical analyses and by 1D and 2D NMR spectroscopy. The following structure of the OPS trisaccharide repeating unit was established. →3)-α-l-Fucp-(1→3)-α-l-Fucp-(1→3)-α-d-Rhap4NAc-(1→.

The bicyclic diaziridine derivative 6-(4-methoxyphenyl)-1,5-diazabicyclo[3.1.0]hexane was synthesized, purified and characterized. Its standard specific energy in the crystalline state at 298.15 K was determined by static bomb combustion calorimetry, from which the standard enthalpies of combustion and formation were calculated. The enthalpy of formation in the gas phase was calculated using the DLPNO-CCSD(T1)/CBS method in combination with isodesmic reactions; the molecular electrostatic potential and group additivity methods were used to estimate the enthalpy of sublimation.

Rathayibacter festucae VKM Ac-1390T (family Microbacteriaceae, class Actinomycetes) contains three rhamnose-containing glycopolymers in the cell wall, the structures of which were established by chemical and NMR spectroscopy methods. The first polymer, a rhamnomannan, consists of repeating tetrasaccharide units with xylopyranose side residues, →2)-α-[β-D-Xylp-(1→3)]-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→. The second polymer found in minor amounts, is a rhamnan, →2)-α-D-Rhap-(1→3)-α-D-Rhap-(1→. The third polymer is a teichuronic acid acetalated with pyruvic acid, →2)-α-[4,6-S-Pyr]-D-Manp-(1→4)-α-L-Rhap-(1→4)-β-D-Glcp-(1→4)-α-D-Glcp-(1→4)-β-D-GlcpA-(1→. The structures of rhamnomannan and teichuronic acid are new for Ratayibacter and prokaryotes in a whole. The results of this study expand our understanding of the structural diversity of microbial glycopolymers and are consistent with previous reports on the species specificity of glycopolymer structures and composition in the genus Rathayibacter.

Catechin, proanthocyanidin B-2, epiafzelechin-(4β→8)-epicatechin, dihydroquercetin, and eriodictyol were isolated via the extraction from the knot wood of plum Renclode blue (Prunus domestica “Renklod sinii”) and subsequent HPLC. Structures of these compounds were confirmed using 2D NMR spectroscopy and mass spectrometry.

The equilibrium molecular structure of 6-(4-chlorophenyl)-1,5-diazabicyclo[3.1.0]hexane (Cl-DABH) has been determined in gas phase based on the data of electron diffraction (GED) method with the use of quantum chemical calculations up to the MP2/cc-pVTZ level of theory. A comparison is made for the main parameters of the molecule in the solid and gas phases. Boat conformation is proven to be dominant in the gas phase.

A water-soluble high-molecular neutral polysaccharide (NP) was isolated from the eggs of the sea urchin Tripneustes gratilla. The formation of glucose only upon the treatment of NP by amyloglucosidase and the value of its optical rotation [α]D +233.5 (c 0.2, water) confirmed its belonging to the family of α-d-glucans. According to the results of NMR spectroscopy and methylation analysis, the chains of NP are built up of non-reducing terminal, 4-linked and 4,6-disubstituted glucose residues at a ratio of 1:8:1. A branched structure with an average linear chain length of about five glucose residues was calculated from the spectrum of iodine complex. Contrary to the previously published structure of branched α-d-glucan from the sea urchin Strongylocentrotus nudus bearing single glucose units as branches, the polysaccharide NP contains oligosaccharide branches at position 6, which was confirmed by NMR data. Hence, NP has a glycogen-like structure with a rather high degree of branching, which markedly exceeds that of usual mammalian or fungal glycogens.

A method for the synthesis of spiro-1,3,4-thiadiazolines by the reaction of cyclic ketones with oxamic acid thiohydrazides was developed. A number of new nonsteroidal spiro-1,3,4-thiadiazolines was obtained in high yields.

Diazotrophic bacteria of the genus Azospirillum are known widely, because they are ubiquitous in the rhizosphere and can promote the growth and performance of nonlegume plants. Recently, more Azospirillum species have been isolated from sources other than plants or soil. We report the structures of the O polysaccharides (OPSs) from the lipopolysaccharides of the type strains A. thiophilum BV-ST (1) and A. griseum L-25-5w-1T (2), isolated from aquatic environments. Both structures have a common tetrarhamnan in the repeating-unit, which is decorated with a side xylose in the OPS of A. thiophilum BV-ST.

The mixtures of starch and pectin were isolated by sequential extraction of the pulp and peel of black radish taproots Raphanus sativus L. with cold, hot and acidified water, solutions of ammonium oxalate, sodium carbonate and sodium hydroxide. The polysaccharide fractions obtained with ammonium oxalate solutions from the pulp and peel of the taproots gave the highest yields. The pectin was the main polysaccharide component. The yield of pectin (calculated on dry matter) from the pulp was 9.5%, from the peel -10.5%. The polysaccharide fractions obtained from pulp with hot water and ammonium oxalate solutions were subjected to sequential enzymatic degradation by amyloglucosidase and polygalacturonase, followed by fractionation on DEAE-cellulose. NMR spectra showed that rhamnogalacturonan-I (RG-I) and galacturonan (HG) regions are in structure of pectin. RG-I has unbranched structure, since there are no signals of 2,4-rhamnose residues in NMR spectra.

This study reports the first general, practical, and facile synthesis of phosphorus-substituted 1,3,4-thiadiazolines starting from phosphorylthioformic acid hydrazides and ketones. Various cyclic ketones were efficiently incorporated into spiro 1,3,4-thiadiazoline derivatives by a two-step sequence involving the heterocyclization with phosphorylthioformic acid hydrazides followed by the nitrogen acylation with acyl chlorides. The protocol is characterized by operational simplicity, readily available reagents, and functional group tolerance.

The cell wall of endophytic strain Rathayibacter oskolensis VKM Ac-2121T (family Microbacteriaceae, class Actinomycetes) was found to contain neutral and acidic glycopolymers. The neutral polymer is a block-type rhamnomannan partially should be substitutied by xylose residues, [→2)-α-[β-D-Xylp-(1→3)]-D-Manp-(1→3)-α-D-Rhap-(1→]∼30 [→2)-α-D-Manp-(1→3)-α-D-Rhap-(1→]∼45. The acidic polymer has branched chain, bearing lactate and pyruvate residues, →4)-α-D-[S-Lac-(2―3)-α-L-Rhap-(1→3)]-D-Manp-(1→3)-α-D-[4,6-R-Pyr]-D-Galp-(1→3)-β-D-Glcp-(1→. The structures of both glycopolymers were not described in the Gram-positive bacteria to date. The glycopolymers were studied by chemical and NMR spectroscopic methods. The results of this study provide new data on diversity of bacterial glycopolymers and may prove useful in the taxonomy of the genus Rathayibacter and for understanding the molecular mechanisms of interaction between plants and plant endophytes.

Comparative analysis of extracellular and cell wall glycans from Urtica cannabina leaves was performed using chemical methods, GC, GC-MS, 1D, and 2D NMR spectroscopy. The structures of extracellular AG-II and cell wall AG-II are similar. The units are typical for AG-IIs: β-GlcpA-4-OMe-(1→, Rhap-(1 → 4)-β-GlcpA-(1→, attached to β-Galp at O-6, as well as arabinan chains attached to β-Galp at O-3. A single Araf and a trisaccharide formed by 2,5-Araf and two terminal Araf form short arabinan side chains in AG-II. 1,5-arabinan with a backbone substituted by a single Araf at O-3 was identified only in the side chains of cell wall AG-II. The side chains can be attached to O-3 and O-6 of the same β-Galp to form a bifurcated AG side chain. The backbone of AG-II is formed by 1,6- rather than 1,3-linked Galp, although it does include some 1,3-Galp. The high content of 3,6-Galp shows the highly branched nature of the AG carbohydrate chains. From the cell wall, AGP was extracted together with pectin, the simultaneous elution of which from both DEAE-cellulose and Sepharose may indicate a link between them.

Estrogen receptor alpha (ERα) is an important target for the discovery of new therapeutic drugs against hormone-dependent breast cancer.

A method for the synthesis of 1,3,4-thiadiazoline spiro steroids via ring A by the reaction of steroid 3-ketones with oxamic acid thiohydrazides was developed. It was shown that if a keto group was present both in ring A and in ring D of the precursor steroid, the reaction occurred only at the keto group of ring A. A number of new steroidal 3-spiroandrostene-substituted 1,3,4-thiadiazolines were obtained, which could be easily acetylated at the thiadiazole NH group.