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Despite the fact that the incidence of leprosy in Russia is sporadic, the number of newly identified patients has increased in recent years. In 2017–2018, 4 new cases of leprosy were registered in Russia. The standard methods of research for diagnosis, in addition to the clinical picture, are bacterioscopic study of the skin scarificates and histological study of the skin biopsy specimen. Currently, additional methods are being developed and used to confirm the diagnosis of leprosy, namely, modern serological and genetic diagnostic methods. To use methods such as enzyme-linked immunosorbent assay (ELISA) and membrane immunochromatographic analysis (leprosy LF serotest), it is appropriate to use domestic synthetic mycobacterial antigens (SMA). Key words: Mycobacterium leprae, leprosy, synthetic mycobacterial antigens, PGL-1(phenolic glycolipid-1), LAM (lipoarabinomannan), serodiagnostics, enzyme-linked immunosorbent assay (ELISA), lateral flow (LF) test, BSA (bovine serum albumin)

Seven artificial mycobacterial antigens have been synthesized via the conjugation of synthetic carbohydrate epitopes of M. leprae phenolic glycolipid (PGL-1) and M. tuberculosis lipoarabinomannan (LAM) with bovine serum albumin (BSA). Each antigen has a different number of carbohydrate epitopes with a different structure and input sequence of the sugar residues. According to the serum reactivity, only three synthesized antigens can be useful for serodiagnosis of mycobacteriosis: (1) the antigen based on a disaccharide derivative of PGL-1: (DMG–Rha-AEP)-[BSA]; (2) the antigen based on a disaccharide fragment of PGL-1 and a hexasaccharide fragment of LAM: (DMG–Rha-AEP)-[BSA]–(Ara6-EG6); (3) the antigen based on the LAM diarabinofuranosyl fragment (Ara2-AEP)–[BSA].

4-(2-Chloroethoxy)phenyl (CEP) aglycon belongs to the class of Janus aglycons and has already been used as a pre-spacer in the synthesis of neoglycoconjugates and as a temporary protective group in the synthesis of oligosaccharides. In the present work, a set of glycosides of various monosaccharides containing CEP aglycon was synthesized. The possibility of modification of CEP aglycon was demonstrated using the corresponding lactoside as an example.

New derivatives of serinol, 3-[4-(2-chloroethoxy)benzyloxy]-2-phthalimidopropan-1-ol and 3-[4-(2-azidoethoxy)phenoxy]-2-phthalimidopropan-1-ol, were synthesized and tested as glycosyl acceptors in stereoselective 1,2-cis-galactosylation in the benzyl-free synthesis of analogs of α-linked galactosylceramides. It was found that NIS/AgOTf-promoted glycosylation of 3-[4-(2-chloroethoxy)benzyloxy]-2-phthalimidopropan-1-ol with ethyl 4,6-O-(di-tert-butylsilylene)-1-thio-β-D-galactoside resulted in both the expected α-linked diastereomeric glycosides and the product of iodination of the benzyl group of the aglycon. This process was avoided by using the corresponding galactosyl imidate under Et3SiOTf promotion to give exclusively α-linked diastereometic serinol glycosides.

Efficient multigram two-step syntheses of 4-(2-chloroethoxy)phenol and 4-(3-chloropropoxy)phenol in >70% yields starting from 4-hydroxybenzaldehyde and reagents with general formula Cl(CH2) n X (X = Cl, n = 2; X = OTs, n = 3) are proposed. 4-(2-Chloroethoxy)phenol can also be conveniently prepared from 4-methoxyphenol and 1,2-dichloroethane. The compounds thus obtained can be used in carbohydrate chemistry to synthesize glycosides bearing "universal" 4-(ω-chloroalkoxy)phenyl aglycons.

O-methylation is an unusual sugar modification with a function that is not fully understood. Given its occurrence and recognition by lectins involved in the immune response, methylated sugars were proposed to represent a conserved pathogen-associated molecular pattern. We describe the interaction of O-methylated saccharides with two β-propeller lectins, the newly described PLL2 from the entomopathogenic bacterium Photorhabdus laumondii, and its homologue PHL from the related human pathogen Photorhabdus asymbiotica. The crystal structures of PLL2 and PHL revealed up to 10 out of 14 potential binding sites per protein subunit to be occupied with O-methylated structures. The avidity effect strengthens the interaction by 4 orders of magnitude. PLL2 and PHL also interfere with the early immune response by modulating the production of reactive oxygen species and phenoloxidase activity. Since bacteria from Photorhabdus spp. have a complex life cycle involving pathogenicity towards different hosts, the involvement of PLL2 and PHL might contribute to the pathogen overcoming insect and human immune system defences in the early stages of infection. DATABASES: Structural data are available in PDB database under the accession numbers 6RG2, 6RGG, 6RFZ, 6RG1, 6RGU, 6RGW, 6RGJ, and 6RGR.

Terminal disaccharide fragment of phenolic glycolipid from Mycobacterium leprae (PGL-I) was synthesized as a glycoside with 4-(2-aminoethoxy)phenyl aglycon. The obtained 4-(2-aminoethoxy)phenyl 4-O-(3,6-di-O-methyl-β-d-glucopyranosyl)-2,3-di-O-methyl-α-l-rhamnopyranoside was used for the synthesis of a series of neoglycoconjugates with bovine serum albumin with different degrees of substitution.

Spacered branched hexaarabinofuranoside, which corresponds to the terminal fragment of mycobacterial lipoarabinomannan and arabinogalactan, was synthesized via three different routes. Synthetic scheme which involved only acyl and silyl protective groups (benzyl-free approach) allows one to reduce the number of deprotection steps, enhance the overall yield, and keep the azido group until the end of the synthesis.

The influence of O-trifluoroacetyl (TFA) groups at different positions of thioglycoside glycosyl donors on stereoselectivity of α-arabinofuranosylation leading to corresponding disaccharides was studied. It was shown that TFA group in thioglycoside glycosyl donors, when combined with 2-O-(triisopropylsilyl) (TIPS) non-participating group, may be regarded as an electron-withdrawing protecting group that may enhance 1,2-cis-selectivity in arabinofuranosylation, the results strongly depending on the nature of glycosyl acceptor. The reactivities of the glycosyl donors were compared with those of a similar thioglycoside with O-pentafluoropropionyl groups and the known phenyl 3,5-O-(di-tert-butylsilylene)-1-thio-α-d-arabinofuranosides with 2-O-TIPS and 2-O-benzyl groups. The 'matching' in the donor-acceptor combination was found to be critical for achieving both high reactivity of glycosyl donor and β-stereoselectivity of arabinofuranosylation. The use of glycosyl donors with TFA and silyl protection may be useful in the realization of the benzyl-free approach to oligoarabinofuranosides with azido group in aglycon-convenient building blocks for the preparation of neoglycoconjugates.

3,6-Di-O-methyl-β-d-glucopyranose neoglycoconjugates with bovine serum albumine and poly(acrylamide) carrier were obtained, which differ in the aglycon nature, linking pattern, and substitution degree.

The Photorhabdus species is a Gram-negative bacteria of the family Morganellaceae that is known for its mutualistic relationship with Heterorhabditis nematodes and pathogenicity toward insects. This study is focused on the characterization of the recombinant lectin PLL3 with an origin in P. laumondii subsp. laumondii. PLL3 belongs to the PLL family of lectins with a seven-bladed &beta, propeller fold. The binding properties of PLL3 were tested by hemagglutination assay, glycan array, isothermal titration calorimetry, and surface plasmon resonance, and its structure was determined by X-ray crystallography. Obtained data revealed that PLL3 binds similar carbohydrates to those that the other PLL family members bind, with some differences in the binding properties. PLL3 exhibited the highest affinity toward l-fucose and its derivatives but was also able to interact with O-methylated glycans and other ligands. Unlike the other members of this family, PLL3 was discovered to be a monomer, which might correspond to a weaker avidity effect compared to homologous lectins. Based on the similarity to the related lectins and their proposed biological function, PLL3 might accompany them during the interaction of P. laumondii with both the nematode partner and the insect host.

Changes in concentration (0.001–0.1 M) of an arabinofuranosyl donor ( 1 ) have been shown to modulate the temperature T at which activation of 1 occurs (from −23 °C to +7 °C), the reaction time (from 1.5 h to 3 days) and the yield of the disaccharide formed (from 14% to 82%). At concentrations exceeding 0.01 M, these parameters, as well as the specific optical rotation of the solution of 1 , virtually do not depend on concentration suggesting formation of reacting species (supramers) of glycosyl donor with similar structures, hence reactivities, but considerably different from those formed in more dilute solutions. The found critical concentration (0.01 M) separates two concentration ranges of reaction solutions corresponding to two types of solution structure that are featured by the presence of fundamentally different supramers of glycosyl donor, which have distinct chemical properties. These results allow a fresh look at the problems of reactivity of chemical compounds and selectivity of the reactions in which they participate.

Two novel azido-derivatives of closo-dodecaborate anion with hydrophobic and hydrophilic spacers were prepared by reaction of tetrabutylammonium azide with cyclic oxonium derivatives of the closo-dodecaborate anion. The compounds prepared can be regarded as precursors of derivatives of closo-dodecaborate anion with amino group at the terminal position of a spacer or as building blocks for ‘click chemistry’, which are useful for preparation of various conjugates with targeting molecules. A concentration dependence of the 11B NMR spectra of functionalized derivatives of closo-dodecaborate anion was discovered, which is of great importance for analytical purposes. Copyright © 2006 John Wiley & Sons, Ltd.

Branched arabinofuranose pentasaccharide with 2-azidoethyl aglycon was prepared for the first time by [3+1+1] bis-(1,2-cis)-glycosylation of trisaccharide diol with silyl-protected thioglycoside glycosyl donor. The presence of 2-azidoethyl aglycon would enable the preparation of neoglycoconjugates using the click chemistry approaches.

A uniform approach to the synthesis of carbohydrate conjugates with polyhedral boron compounds (PBCs) was developed. Oligosaccharide derivatives with an aglycone moiety amino group can be coupled with PBC carboxyl derivatives using N-methyl-N-(4,6-dimethoxy-1,3,5-triazin-2-yl)morpholinium chloride as a coupling agent. Both N- and O-glycosides differing in the conformational mobility around the glycoside bond were shown to be useful as oligosaccharides with a functional group in the aglycone moiety. This allows the application of this approach to the synthesis of PBC conjugates with a wide range of oligosaccharides. For example, not only oligosaccharides obtained by chemical synthesis but also reducing oligosaccharides isolated from natural sources can be transformed into N-glycosides. The approach was tested by the example of conjugation of the carboxyl derivatives of ortho-carborane and dodecaborate anion with lactose as a model oligosaccharide. Lactose, an easily available disaccharide, is a ligand for lectins expressed on the surface of melanoma cells. The approach suggested is the first example of the synthesis of such conjugates that does not require protective groups for the carbohydrate residue. It is especially important for obtaining dodecaborate-carbohydrate conjugates for which the removal of protective groups is often a non-trivial task.

aHigher Chemical College of the Russian Academy of Sciences, 9 Miusskaya pl., 125047 Moscow, Russian Federation. bN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation. Fax: +7 (095) 135 5328. E mail: kononov@ioc.ac.ru cA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, 119991 Moscow, Russian Federation. Fax: +7 (095) 135 5085. E mail: bre@ineos.ac.ru

The results of the work of 6 health posts at electrical engineering plants of the Ukrainian Society of treh Blind are presented. The number of attendencies for invalids with eyesight disorders constituted 29.5 annually, for those with good eyesight it was 6.7. Time losses for a curative and diagnostic consultation and provision of medical care to invalids of the Ist group with eyesight disorders exceeded the time necessary for rendering care to those who could see by 31-34%. Feldshers spent 43.6% of their working time and medical nurses 65.3% on medical care. Attendencies associated with psychic disorders were listed as one of the biggest health problems in the disease pattern of the blind and those with weak eyesight, 91.1% of psychic cases being attributed to vegeto-vascular dystonia, diseases of the circulatory system, injuries and their aftereffects. A set of proposals was developed, thus it became possible to regulate the work of the health personnel of health posts at the enterprises belonging to the Society of the Blind.