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An extracellular polymer was isolated from the culture liquid of Bacillus subtilis EGP5QL12 with the yield of 5,6 g/L. On the basis of the data of thin layer chromatography, colorimetric analyses and FTIR spectroscopy, it was established that the polymer is poly-γ- glutamic acid (PGA). PGA is widely used in medicine, cosmetology and the food industry due to its ability to bind water and metal ions. To assess the biotechnological potential of the isolated polymer and predict the possibilities of its application in various fields of the national economy, it is necessary to analyze the characteristic spectral features that make it possible to establish its secondary structure. The isolated PGA preparation was analyzed by circular dichroism spectroscopy at various pH values. According to the results of this study, it was found that the polymer forms predominantly β-structures with a low proportion of irregular structures and α-helices, which gives it a high potential for creating hydrogels and composite materials.

Significant researches aimed at the greening of agro-industrial production are focused on obtaining immobilized bacterial preparations with preserved proliferative function and metabolic activity. Herein, we investigated the possibility of bacteria of the genus Azospirillum to be immobilized in Ca-alginate beads. A. brasilense SR80 cells, encapsulated in an alginate hydrogel, were obtained using the “soft” immobilization method based on physical binding. We demonstrated the retained respiratory activity and growth ability of the bacteria during immobilization, thus confirming the advantageous prospects of alginate templates for azospirilla encapsulation.

Here, the results of the structure and the activity of capsular polysaccharides isolated from the Halomonas aquamarina EG27S8QL and Cobetia pacifica KMM3878 have been described. Both polysaccharides were studied by spectroscopic and chemical methods and were found to be structurally related sulfated galactans differing in the position of the sulfate group: →6)-β-D-Galp3S-(1 → 4)-β-D-Galp3S-(1 → 6)-β-D-Galp3,4(S-Pyr)-(1 → [H. aquamarina EG27S8QL] →6)-β-D-Gal-(1 → 4)-β-D-Gal2,3S-(1 → 6)-β-D-Gal3,4(S-Pyr)-(1 → [C. pacifica KMM3878] Structure of the CPS from H. aquamarina EG27S8QL has not been hitherto reported, whereas the CPS from C. pacifica KMM3878 was identical to the previously studied O-polysaccharide. The CPSs exhibited an antiproliferative effect and suppressed the colony formation of DLD-1 and MCF-7 cells in a different manner.

A strain, 3EQS1, was isolated from a salt sample taken from Lake Qarun (Fayoum Province, Egypt). On the basis of physiological, biochemical, and phylogenetic analyses, the strain was classified as Chromohalobacter salexigens. By 72 h of growth at 25 °С, strain 3EQS1 produced large amounts (15.1 g L− 1) of exopolysaccharide (EPS) in a liquid mineral medium (initial рН 8.0) containing 10% sucrose and 10% NaCl. The EPS was precipitated from the cell-free culture medium with chilled ethanol and was purified by gel-permeation and anion-exchange chromatography. The molecular mass of the EPS was 0.9×106 Da. Chemical analyses, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy showed that the EPS was a linear β-d-(2→6)-linked fructan (levan). In aqueous solution, the EPS tended to form supramolecular aggregates with a critical aggregation concentration of 240 µg mL-1. The EPS had high emulsifying activity (E24, %) against kerosene (31.2 ± 0.4%), sunflower oil (76.9 ± 1.3%), and crude oil (98.9 ± 0.8%), and it also had surfactant properties. A 0.1% (w/v) aqueous EPS solution reduced the surface tension of water by 11.9%. The levan of C. salexigens 3EQS1 may be useful in various biotechnological processes.

We propose a novel keratin treatment of human hair by its aqueous mixtures with natural halloysite clay nanotubes. The loaded clay nanotubes together with free keratin produce micrometer-thick protective coating on hair. First, colloidal and structural properties of halloysite/keratin dispersions and the nanotube loaded with this protein were investigated. Above the keratin isoelectric point (pH = 4), the protein adsorption into the positive halloysite lumen is favored because of the electrostatic attractions. The ζ-potential magnitude of these core-shell particles increased from -35 (in pristine form) to -43 mV allowing for an enhanced colloidal stability (15 h at pH = 6). This keratin-clay tubule nanocomposite was used for the immersion treatment of hair. Three-dimensional-measuring laser scanning microscopy demonstrated that 50-60% of the hair surface coverage can be achieved with 1 wt % suspension application. Hair samples have been exposed to UV irradiation for times up to 72 h to explore the protection capacity of this coating by monitoring the cysteine oxidation products. The nanocomposites of halloysite and keratin prevent the deterioration of human hair as evident by significant inhibition of cysteic acid. The successful hair structure protection was also visually confirmed by atomic force microscopy and dark-field hyperspectral microscopy. The proposed formulation represents a promising strategy for a sustainable medical coating on the hair, which remediates UV irradiation stress.

The paper reports the structural study of the lipopolysaccharide from the type strain of the soil nitrogen-fixing bacterium Azospirillum rugosum isolated from oil-polluted soils. Based on the chemical analysis and 1D- and 2D 1H and 13С NMR spectroscopy data it has been demonstrated that the O-specific polysaccharide consists of the two types of repeating units identical to those previously described for the O-specific polysaccharide of the Azospirillum brasilense strain Jm125A2. Structural analysis of the lipid A using gas-liquid chromatography (GLC) and MALDI mass spectrometry revealed the presence of penta-, tetra-, and triacylated species. The primary fatty acids in the lipid A are the N-linked 16:0(3-OH) and О-linked 14:0(3-OH). Microheterogeneity within each species arises from the presence of different secondary fatty acids (16:0, 18:1, or 19:0) acylating the 16:0(3-OH) acid of the distal GlcN ring.

Reversing the organization of oil-in-water Pickering emulsion formed with halloysite nanoclay, liquid marbles were created with water droplets encapsulated by a layer of clay nanotubes. After incor...

A halophilic bacterial strain, EG1HP4QL, was isolated from a salt sample from Lake Qarun, Fayoum Province, Egypt. Morphological, physiological, biochemical, and phylogenetic analyses indicated that the strain belonged to the genus Halobacillus. Strain EG1HP4QL produced an extracellular polysaccharide (EPS), with production peaking (5.9 g L−1) during growth on medium S-G containing 2% (w/v) sucrose at 35 °C (pH 8.0). The EPS had significant emulsifying activity (E24 %) against kerosene (65.7 ± 0.8%), o-xylene (64.0 ± 1%), and sunflower oil (44.7 ± 0.5%). The composition of the EPS included two polymers—a negatively charged and a neutral one (~ 3:1)—in which mannose and glucose were the main neutral monosaccharide constituents. Strain EG1HP4QL was able to utilize crude oil (35.3%) as the sole carbon source within 12 days. The minimum inhibitory concentrations of heavy metals [Zn(II), Cd(II), Pb(II), Ni(II), and Cu(II)] for strain EG1HP4QL were 1.0, 2.0, 2.0, 2.5, and 5 mM, respectively.

O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of plant-growth-promoting rhizobacteria Azospirillum doebereinerae GSF71T and studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments. It was established that the polysaccharide is linear and consists of tetrasaccharide repeating units with the following structure.

Lipopolysaccharide (LPS) was extracted from dry bacterial cells of plant-growth-promoting bacterium Azospirillum brasilense SR8 (IBPPM 5). The O-specific polysaccharide (OPS) was obtained by mild acid hydrolysis of the lipopolysaccharide and studied by sugar analysis, 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, and 1H,13C HSQC and HMBC experiments, computational NMR-based structure analysis, and Smith degradation. The OPS was shown to contain two types of repeating units of the following structure: Both OPS structures are present in A. brasilense 54, from which structure 1 has been reported earlier (Fedonenko et al., 2011), whereas to our knowledge structure 2 has not been hitherto found in bacterial saccharides. Treatment of wheat seedling roots with LPS of A. brasilense SR8 increased the number of root hair deformations as compared to seedlings grown without LPS, but had no effect on adsorption of the bacteria to the root surface. A. brasilense SR8 was able to utilize LPS of several structurally related Azospirillum strains.

Halomonas ventosae RU5S2EL, a halophilic Gram-negative bacterium isolated from salt sediments of lake Elton (Russia), was cultivated and the lipopolysaccharide was extracted by the Westphal procedure. The O-specific polysaccharide (OPS) was obtained by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments as well as Smith degradation. The OPS was found to consist of branched pentasaccharide repeating units of the following structure.

Topical administration of drugs is required for the treatment of parasitic diseases and insect infestations, therefore, fabrication of nanoscale drug carriers for effective insecticide topical delivery is needed. Here we report the enhanced immobilization of halloysite tubule nanoclay onto semiaquatic capybaras which have hydrophobic hair surfaces as compared to their close relatives, land-dwelling guinea pigs, and other agricultural livestock. The hair surface of mammals varies in hydrophobicity having a cortex surrounded by cuticles. Spontaneous 1–2 µm thick halloysite hair coverages on the semi-aquatic rodent capybara, non-aquatic rodent guinea pig, and farm goats were compared. The best coating was found for capybara due to the elevated 5 wt% wax content. As a result, we suggest hair pretreatment with diluted wax for enhanced nanoclay adsorption. The formation of a stable goat hair coverage with a 2–3 µm halloysite layer loaded with permethrin insecticide allowed for long-lasting anti-parasitic protection, enduring multiple rain wettings and washings. We expect that our technology will find applications in animal parasitosis protection and may be extended to prolonged human anti-lice treatment.

For six strains of halophilic bacteria, nitrogen fixation ability, production of phytohormones and siderophores, the solubilization of phosphates, and heavy metal resistance were revealed.

According to the physiological-morphological and molecular-biological characteristics, the halophilic representative of archaea strain-isolate from the saltworks of lake Karun (Egypt) was identified as Haloterrigena saccharevitans EG3QL57. The ability of H. saccharevitans EG3QL57 to utilize oil with an efficiency of 27.4%, resistance to the presence of concentrations of up to 5 mm of heavy metals in the growth medium is shown. It is shown that when the growth conditions of microorganisms are optimized, they produce up to 2.3 g/l of exopolysaccharides (EPS).

Based on biochemical and phylogenetic analyses, isolated from a salt sample from Lake Qarun (Egypt) a halophilic strain EG1QL3 was identified as Chromohalobacter salexigens. The abilities of EG1QL3 to produce an extracellular polysaccharide, degrade oil, and resist to heavy metals were revealed.

Here we overview the recent advances in the fabrication of sustainable composite nanomaterials with decontamination capacity towards inorganic and organic pollutants. In this regards, we present the development of hybrid systems based on clay nanoparticles with different shapes (such as kaolinite nanosheets and halloysite nanotubes) and organic molecules (biopolymers, surfactants, cucurbituril) as efficient removal agents for both aliphatic and aromatic hydrocarbons. Due to their high specific surface area, clay nanoparticles have been successfully employed as fillers for composite membranes with excellent filtration capacity. The preparation of composite gel beads based on biopolymers (alginate and pectin) and halloysite nanotubes has been discussed and their adsorption capacities towards both heavy metals and organic dyes have been highlighted. We describe the successful preparation of kaolinite/graphene composites as well as tubular inorganic micelles obtained by the select functionalization of the halloysite cavity with anionic surfactants. Finally, recent research on Pickering emulsions (for oil spill remediation) and bioremediation technologies has been discussed.

The lipopolysaccharide was obtained from the cells of Azospirillum formosense CC-Nfb-7(T), a diazotrophic bacterium isolated from agricultural soil. The O-specific polysaccharide (OPS) was released by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments, and Smith degradation. The following structure of partially methylated OPS composed of trisaccharide repeating units was established.

Combined spectroscopic and biochemical measurements were used to improve diagnostic accuracy and to evaluate gastrointestinal tract (GIT) neoplasia development parameters noninvasively. Experiments were performed in mongrel male rats divided into 2 groups – control and experimental. To induce gastric cancer, the rats underwent to chronic stress (overpopulation during 9 months) and diet including the daily using of mtoluidine (25 μg/kg weight) in food and water with a solution of sodium nitrite (0.2%) for 9 months. We studied effectiveness of 5-ALA/PpIX fluorescent analysis of gastric carcinoma and biochemical stress-corresponding indices detection for early diagnosis of primary gastric tumours and their metastatic spreading in liver. Affected by precancerous and cancerous alterations mucosa reveal red fluorescence, related to the accumulation of 5- ALA/PpIX. Liver tissues investigated also presented increase of the red fluorescence, which was used as an indicator for possible pathologic process detection there. The histological examination revealed liver metastases in 67.8 % of the rats with gastric cancer. Biochemical indicators detected malignant alterations presence in GIT, and fluorescent observation addressed the exact area and borders of neoplastic lesions. 5-ALA/PpIX fluorescence detection allow to find and precisely map premalignant and malignant areas of gastric mucosa and liver metastases of stress-induced gastric heterogeneous adenocarcinoma and biochemical evaluation of stressrelated compounds increased the efficiency of such diagnosis and reveal information about the dynamics of lesions development. Diagnostic accuracy achieved using fluorescent detection reaches 93% for gastric carcinoma, and 87% for pre-cancerous mucosa alterations observed.

Lipopolysaccharide was isolated by phenol extraction from the surface membrane of the nitrogen-fixing endophytic rhizobacterium Herbaspirillum seropedicae, strain Z78. The lipopolysaccharide’s lipid A contained 3-hydroxydecanoic, 3-hydroxydodecanoic, dodecanoic, tetradecanoic, and hexadecanoic acids. The 3-hydroxydodecanoic acid was amide-linked to the sugar backbone of the lipid A. The structure of the O-polysaccharide from H. seropedicae Z78 was established for the first time. It is characterized by heterogeneity and by the presence of glycerol, a component rarely found in gram-negative bacteria. The O polysaccharide of H. seropedicae Z78 was found to consist of two types of repeating units: one represented by glycerol-1-phosphate and the other by the glycerol-1-phosphate of the backbone, which is substituted at the 2-position by N-acetyl-D-glucosamine. The lipopolysaccharide of the H. seropedicae Z78 was weakly toxic to warm-blooded animals and moderately and dose-dependently induced interleukin synthesis by human whole blood cells and NO synthesis by mouse splenocytes. This may indicate that the H. seropedicae lipopolysaccharide is a promising antagonist of classical endotoxins.

Bacterial polysaccharides are promising stimulants of protective functions in humans and animals. We investigated the ability of exopolysaccharide from the rhizobacterium Paenibacillus polymyxa CCM 1465 to induce nonspecific resistance factors in the macroorganism. We examined in vitro the effect of the exopolysaccharide, produced with different carbon sources, on the phagocytic activity of murine macrophages, on the generation of reactive oxygen species and of enzymes (acid phosphatase and myeloperoxidase), on the proliferation of murine splenocytes, and on the synthesis of proinflammatory cytokines [interleukin-1 (IL-1) and tumor necrosis factor α (TNF-α)] by human mononuclear cells. The exopolysaccharide promoted the phagocytosis of bacterial cells, activated metabolic processes in human and animal leukocytes, and moderately affected the production of TNF-α and IL-1β. The exopolysaccharides produced on media with glucose and sucrose differed in their effect on the immune cells, possibly owing to their different compositions, structures, and properties. The results validly indicate that the exopolysaccharide of P. polymyxa CCM 1465 promotes nonspecific immunity. Therefore, it can find application as a biologically active immunomodulatory substance.

The article touches upon the income of the population as an indicator of welfare and living standard of the people in the Astrakhan region. According to such indicators as real cash incomes, real accrued wages and the actual size of pensions, there has been drawn a conclusion about welfare of residents of Astrakhan. The article has identified a trend towards decreasing income growth of the population. It has been stated in the article that about one third of the population of the Astrakhan region need additional income to satisfy long-term requirements, and only five percent of the population don't restrain their spending capacity.

Gastrointestinal cancerous lesions were induced in laboratorial animals using prolonged exposure to social (overpopulation) and chemical stress (nitrosamine diet), mimicking typical stress factors for humans in the big cities. Twenty laboratorial rats with developed stress-induced neoplasia in gastrointestinal tract were used. Three of them formed control group - without application of exogenous contrast fluorescent marker. Exogenous fluorescent spectroscopic measurements were used to evaluate gastrointestinal tract (GIT) neoplasia development noninvasively using excitation at 405 nm and emission was detected in the region of 500-850 nm using microspectrometer. We used as exogenous fluorescent marker protoporphyrin IX applying its precursor delta aminolevulinic acid in a dose of 20mg/kg, in laboratorial rats with stress-induced neoplasia. Spectroscopic analysis of primary gastric tumours and their metastases spreading in rats’ liver was carried out on animals in vivo, as excitation and emission light were delivered by fiberoptic probe 6+1 to the organs investigated during open surgery procedure. Biochemical indicators detected malignant alterations presence in GIT were also evaluated and used as complementary indices for lesions’ growth. Fluorescent observation using exogenous fluorophore addressed the exact area and borders of neoplastic lesions in stomach and liver. In some cases in inflammatory areas significant accumulation of delta-ALA had place, which lead to false-positive fluorescent signal of protoporphyrin IX in these tissues. Photodiagnostics accuracy of 93% was reached for cancerous cases and 87% for gastric pre-cancer lesions evaluation. Very good correlation between fluorescence data and histology examination of the lesions investigated was achieved as well.

Gastric cancer is the main cause of death among oncological diseases of the gastrointestinal tract, which is associated with the difficulty of early diagnosis of this disease. This study aims to develop a new method for diagnosing gastric cancer using the delta-aminolevulinic acid / protoporphyrin IX photosensitizer (5-ALA / PpIX). The experiments were performed on white rats of average weight 250 grams. The animals were divided into 2 groups: control and experimental (stress + diet, including nitrites and carcinogenic amines) ones. The results of the studies, averaged for each type of tissue, clearly show significant differences between normal, precancerous and malignant changes in the stomach tissues of rats on the background of application of photodynamic diagnostics. The fluorescence from malignant neoplasms in the organ was maximal at 635 nm, which corresponds to the maximum emission of protoporphyrin due to the high accumulation of this photosensitizer in the affected tissues. The most important result of the study was the detection of precancerous changes (atrophic gastritis, confirmed by histological methods), using photodynamic diagnostics with photosensitizer 5-ALA / PpIX. Intensity of fluorescence in case of precancerous changes occupied an intermediate value between that in normal and in malignant mucosa of the stomach.

Here we report a detailed investigation of the interaction of neuronal progenitor cells and neurons with polyelectrolyte-stabilized magnetic iron oxide nanoparticles. Human neuronal progenitor and neurons were differentiated in vitro from fibroblast-derived induced pluripotent stem cells. The cytotoxic effects of poly(allylamine hydrochloride) were determined on human skin fibroblasts and neuronal progenitor cells. Immunocytochemical staining of lamins A/C and B in cells treated separately with poly(allylamine hydrochloride) and magnetic nanoparticles allowed to exclude these nuclear components as targets of toxic effects. We demonstrate that magnetic nanoparticles accumulated in cytoplasm and on the surface of neuronal progenitor cells neither interacted with the nuclear envelope nor penetrated into the nuclei of neuronal cells. The possibility of guidance of magnetically functionalized neuronal progenitor cells under magnetic field was demonstrated. Magnetization of progenitor cells using poly(allylaminehydrochloride)-stabilized magnetic nanoparticles allows for successful managing their in vitro localization in a monolayer.

Effect of the carbon source in the culture medium and of the growth phase on the composition and structure of the capsular polysaccharides (CPSs) and lipopolysaccharides (LPSs) of the bacterium Azospirillum brasilense Sp245 was studied. Growth with fructose resulted in an increased carbohydrate content in the CPSs, while long-term cultivation resulted in an increased content of phosphorus in both CPSs and LPSs. The LPSs produced on the medium with fructose (regardless of the cultivation duration) and the LPSs of the bacteria grown with sodium malate until the stationary phase were characterized by higher levels of unsaturated fatty acids than the LPSs of the bacteria grown with sodium malate to the late exponential phase. The structures of the polysaccharides from the isolated glycopolymers were established using monosaccharide analysis, including determination of the absolute configurations and 1D and 2D NMR spectroscopy. This study is the first to report that the CPS of A. brasilense Sp245 grown with sodium malate to the end of the exponential phase is structurally identical to the O-polysaccharide from the LPS of this bacterium and that the LPS and CPS of A. brasilense Sp245 grown with fructose contain an additional homoglucan of the following structure: [→3)-α-D-Glcp-(1→] n .

The modified polyelectrolyte-magnetite nanocoating was applied to functionalize the cell walls of oil decomposing bacteria Alcanivorax borkumensis. Cationic coacervate of poly(allylamine) and 20 nm iron oxide nanoparticles allowed for a rapid single-step encapsulation process exploiting electrostatic interaction with bacteria surfaces. The bacteria were covered with rough 70-100-nm-thick shells of magnetite loosely bound to the surface through polycations. This encapsulation allowed for external manipulations of A. borkumensis with magnetic field, as demonstrated by magnetically facilitated cell displacement on the agar substrate. Magnetic coating was naturally removed after multiple cell proliferations providing next generations of the cell in the native nonmagnetic form. The discharged biosurfactant vesicles indicating the bacterial functionality (150 ± 50 nm lipid micelles) were visualized with atomic force microscopy in the bacterial biofilms.

O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of nitrogen-fixing bacterium Azospirillum fermentarium CC-LY743 T (IBPPM 578) and was studied by sugar analysis along with 1 H and 13 C NMR spectroscopy, including 1 H, 1 H COSY, TOCSY, ROESY, and 1 H, 13 C HSQC and HMBC experiments. The polysaccharide was found to be linear and to consist of alterating α- l -fucose and α- d -mannose residues in tetrasaccharide repeating units of the following structure: →2)-α-D-Man p -(1 → 3)-α-L-Fuc p -(1 → 3)-α-D-Man p -(1 → 3)-α-L-Fuc p -(1→

Recent reports have shown significant improvement of the polymerase chain reaction (PCR) efficiency and specificity with the addition of gold nanoparticles (AuNPs). However, the underlying mechanisms are still unclear and debatable. Here, we report effects of AuNP concentration, shape, material, and surface functionalization on PCR outcome under typical amplification conditions. All nanoparticles were tested with two PCR diagnostic models: (1) the nitrogen fixation (NifD) gene from Azospirillum brasilense Sp7 bacteria and (2) the polymorphic ompA gene encoding major outer membrane protein of Chlamydia trachomatis. The optimal concentration of 16 nm citrate-stabilized negatively charged spherical AuNPs (zeta potential −29.9 mV) was determined to be 0.4 nM, in agreement with previous data for quite different PCR systems. Functionalization with poly(vinylpyrrolidone) (PVP) and thiolated PEG (mPEG-SH) essentially did not change the zeta-potential (−30 mV and −21 mV, respectively), but completely suppressed the PCR enhancement. Positively charged AuNPs with poly(diallyldimethylammonium) (PDDA) and cetyltrimethylammonium bromide (CTAB) capping polymers exhibited no specific enhancing effect on PCR or even inhibited the reaction at 5 pM of AuNP–PDDA. Also, no specific PCR enhancement was obtained with CTAB-stabilized gold nanorods. To elucidate the role of the particle material, we performed PCR with gold and silica particles of comparable size and equal negative charges. In contrast to the great PCR enhancement with 16 nm AuNPs, 20 nm silica nanoparticles did not affect the PCR efficiency or inhibit the reaction at concentrations higher than 100 nM. These findings suggest that the nature of the PCR system components, surface stabilizing agents and the thermal conductivity of the nanoparticle material can play important roles in the nanoparticle-mediated PCR.

Two polysaccharides were obtained by mild acid degradation of the lipopolysaccharide of associative nitrogen-fixing bacteria Azospirillum brasilense Jm125A2 isolated from the rhizosphere of a pearl millet. The following structures of the polysaccharides were established by sugar and methylation analyses, Smith degradation, and (1)H and (13)C NMR spectroscopy: [Formula: see text] Structure 1 has been reported earlier for a polysaccharide from A. brasilense S17 (Fedonenko YP, Konnova ON, Zdorovenko EL, Konnova SA, Zatonsky GV, Shaskov AS, Ignatov VV, Knirel YA. Carbohydr Res 2008;343:810-6), whereas to our knowledge structure 2 has not been hitherto found in bacterial polysaccharides.

The review presents a discussion of the published data of 2002 to 2014 dealing with structural studies of O-specific polysaccharides, representatives of the Azospirillum diazotrophic rhizobacteria, summarizing the results of a series of authors´ studies. Some general structures incorporated in O-specific polysaccharides responsible for classification of bacterial cultures into serogroups on the basis of immunochemical studies were characterized. The structures of O-specific polysaccharides of seven azospirillum strains identical to those of previously studied strains are presented in this review for the first time.

Here, we report a scalable and rapid method to fabricate magnetically responsive agarose microgels doped with microbial cells. Low-temperature melting agarose and food-grade sunflower oil were used to fabricate microbeads during emulsification and gel setting. Microscopic algae and fungi cells were doped into ∼100-μm-sized beads as single culture or mixed. Magnetic nanoparticles were deposited either on cell walls or on bead walls. We found that the cells encapsulated in magnetically responsive microbeads were viable and able for germination.

Fabrication of “cyborg” cells (biological cells with surfaces functionalised using a variety of nanomaterials) has become a fascinating area in cell surface engineering. Here we report a simple procedure for fabrication of polycation-stabilised 50 nm silver nanoparticles and application of these nanoparticles for fabrication of viable “cyborg” microbial cells (yeast and bacteria). Cationic polymer-stabilised nanoparticles electrostatically adhere to microbial cells producing an even monolayer on the cell walls, as demonstrated using enhanced dark-field microscopy, atomic force microscopy and microelectrophoresis. Our procedure is exceptionally fast, being completed within 20 min after introduction of cells into nanoparticle aqueous suspensions. Polymer-stabilised silver nanoparticles are highly biocompatible, with viability rates reaching 97%. We utilised “cyborg” cells built using bacteria and silver nanoparticles to deliver nanoparticles into C. elegans microworms. We believe that the technique described here will find numerous applications in cell surface engineering.

We obtained impedance dispersion curves of stomach and liver tissues of rats in dynamics, while affecting with tumorigenic inductors: sodium nitrite (0.2%) and m-toluidine (25 mg per 1 kg body weight) in chronic experiment (over 10 months) in male outbred white rats aged 3 and 14 months at the beginning of the experiment. A substantial decrease in the impedance values for all test frequencies (50 Hz to 1 MHz) was shown.

Lipopolysaccharides of six Azospirillum brasilense strains (SR50, SR80, SR88, SR109, SR111, SR115) and A. lipoferum SR 42 isolated from the rhizosphere of cereal plants of Saratov oblast, Russia and referred to serogroup II by serological analysis were studied. In the lipid A fatty acid composition, the lipopolysaccharides under study were similar to those of other Azospirillum strains and were characterized by a predominance of 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, and octadecenoic acids. Monosaccharide analysis of the O-specific polysaccharides (including determination of the absolute configurations, methylation analysis, and one- and two-dimensional NMR spectroscopy) revealed the presence of two types of repeating units in varying ratios. A high degree of serological similarity between the strains under study was shown to result from the presence of repeating units with identical structure of their O antigens.

Cultivation of the type strain Azospirillum lipoferum Sp59b in the presence of flavonoid quercetin induced modification of the structure of the bacterial lipopolysaccharide. Cultivation in the presence of the flavonoid was shown to result in altered serological characteristics of the bacteria, increased heterogeneity of the outer membrane lipopolysaccharide pool, as well as in modified composition and fatty acid ratio of lipid A. The flavonoid was shown to induce the synthesis of the O-specific polysaccharide with the repeating structure represented by a tetrasaccharide consisting of a linear trisaccharide fragment of α-L-Rhap residues in the main chain and the terminal β-D-Glcp residue. The structure of this O-specific polysaccharide was identical to the previously determined structure of the capsular polysaccharide of these bacteria grown without quercetin. Modifications in the structural composition of the capsular polysaccharide induced by cultivation in the presence of quercetin were revealed.

Lipopolysaccharide was obtained by phenol-water extraction from dried bacterial cells of Azospirillum brasilense type strain Sp7. Mild acid hydrolysis of the lipopolysaccharide followed by GPC on Sephadex G-50 resulted in a polysaccharide mixture, which was studied by composition and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy. The following polysaccharide structures were established, where italics indicate a non-stoichiometric (∼40%) 2-O-methylation of l-rhamnose.

The repeating unit structure of Azospirillum irakense KBC1 capsular polysaccharide (CPS) was established and was found to be identical to that of the O polysaccharide of A. irakense KBC1 lipopolysaccharide (LPS). The antigenic heterogeneity of the LPS and the CPS was shown to be related to differences in the macromolecular organization of these glycopolymers. After an immune response activation, R-form CPS molecules were found to be predominant.