Development of a guar gum film with lysine clonixinate for periodontal treatments.

Periodontal pain is a public health problem derived from different conditions, including periodontal diseases, prosthetic complications, and even extractions performed by dentist. There are various treatments to control acute dental pain, being the administration of analgesics, such as Lysine Clonixinate (LC), a common practice. Unfortunately, higher and repeated dosages are usually required. The purpose of this work was to develop a prolonged release pharmaceutical form as an alternative treatment for dental pain. Hence, we conceived a film based on guar gum and loaded different concentrations of LC. We evaluated the film's appearance, brittleness, strength, and flexibility, and then chose one formulation for adequate characteristics. Subsequently, we assessed the morphology, thermal behavior, and swelling properties of the films (LC-free and -loaded). Finally, we performed the release studies of LC from the films in vitro using a simulated saliva medium and employed several mathematical models to evaluate the release kinetics. Guar gum is a natural polymer obtained from the endosperm of Cyamopsis tetragonolobus that presents properties such as biosafety, biocompatibility, and biodegradability. Thus, it represents a potential excipient for use in pharmaceutical formulations. Moreover, our results revealed that the LC-loaded film presented a high adherence, suitable swelling behavior, high LC content, and a prolonged drug release. Therefore, the LC-loaded film may be considered a potential option to be applied as an alternative to treat dental pain.

Development of a xanthan gum film for the possible treatment of vaginal infections.

Bacterial vaginosis is a vaginal infection that affects 60% of women of reproductive age worldwide. It is mainly caused by the bacterium Gardnerella vaginalis and is a factor that increases the probability of getting sexually transmitted diseases. We aimed to develop a new pharmaceutical form for the treatment of vaginal infections. We employed the solving-casting method to fabricate a polymeric film with Xanthan gum, a natural polymer produced by the bacterium Xanthomonas campestris, and metronidazole, one of the most commonly used drugs for vaginal infections. In order to characterize the film, we measured pH, dose uniformity, dissolution profile, and the percentage of swelling. Moreover, we performed a thermogravimetric analysis and scanning electron microscopy. The results demonstrated a pH suitable for vaginal application and uniform distribution of the drug in the film. Also, the formulation exhibited a high percentage of swelling and a slow release of the drug in a simulated vaginal fluid medium. All these attributes indicated that the manufactured film has ideal characteristics to be used and administered vaginally. It could be an excellent alternative to treat bacterial vaginosis and also improve user adherence.

Prospective bioremediation of toxic heavy metals in water by surfactant exopolysaccharide of Ochrobactrum pseudintermedium using cost-effective substrate.

Globally, the underlying peril of cumulative toxicity of heavy metals in water bodies contaminated by industrial effluents is a matter of great concern to the environmentalists. Heavy metals like lead, cadmium, and nickel are particularly liable for this. Such toxic water is not only hazardous to human health but also harmful to aquatic animals. Remedial measures are being taken by physico-chemical techniques, but most of them are neither eco-friendly nor cost-effective. Biological means like bioaccumulation of heavy metals by viable bacteria are often tedious. In the present study, biosorption of heavy metals is successfully expedited by surfactant exopolysaccharide (SEPS) of Ochrobactrum pseudintermedium C1 as a simple, safe, and economically sustainable option utilizing an easily available and cost-effective substrate like molasses extract. Its efficacy in bioremediation of toxic heavy metals like cadmium, nickel, and lead have been studied by UV-Vis spectrophotometry and verified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). FTIR and zeta potential studies have also been carried out to explore this novel biosorption potential. Results are conclusive and promising. Moreover, this particular SEPS alone can remediate all these three toxic heavy metals in water. For futuristic applications, it might be a prospective and cost-effective resource for bioremediation of toxic heavy metals in aqueous environment.

Bacterial cellulose-based magnetic nanocomposites: A review.

Bacterial cellulose (BC) is a natural polymer that has unique and interesting structural, physical and chemical properties. These characteristics make it very attractive as a starting point for several novel developments in innovative research. However, the pristine BC lacks certain properties, in particular, magnetic property, which can be imparted to BC by incorporation of several types of magnetic nanoparticles. Magnetic nanocomposites based on BC exhibit additional magnetic functionality on top of the excellent properties of pristine BC, which make them promising materials with potential uses in various medical and environmental applications, as well as in advanced electronic devices. This review has compiled information about all classes of BC magnetic nanocomposites fabricated by various synthesis approaches and an overview of applications as well as improved features of these materials. A summary of the key developments of BC magnetic nanocomposites and emphasis on novel advances in this field is presented.

Bacterial Nanocellulose in Dentistry: Perspectives and Challenges.

Bacterial cellulose (BC) is a natural polymer that has fascinating attributes, such as biocompatibility, low cost, and ease of processing, being considered a very interesting biomaterial due to its options for moldability and combination. Thus, BC-based compounds (for example, BC/collagen, BC/gelatin, BC/fibroin, BC/chitosan, etc.) have improved properties and/or functionality, allowing for various biomedical applications, such as artificial blood vessels and microvessels, artificial skin, and wounds dressing among others. Despite the wide applicability in biomedicine and tissue engineering, there is a lack of updated scientific reports on applications related to dentistry, since BC has great potential for this. It has been used mainly in the regeneration of periodontal tissue, surgical dressings, intraoral wounds, and also in the regeneration of pulp tissue. This review describes the properties and advantages of some BC studies focused on dental and oral applications, including the design of implants, scaffolds, and wound-dressing materials, as well as carriers for drug delivery in dentistry. Aligned to the current trends and biotechnology evolutions, BC-based nanocomposites offer a great field to be explored and other novel features can be expected in relation to oral and bone tissue repair in the near future.

Molecular α-relaxation process of exopolysaccharides extracted from Nostoc commune cyanobacteria.

Broadband dielectric spectroscopy was used to investigate the molecular α-relaxation of the exopolysaccharides (EPS) extracted from Nostoc commune cyanobacteria. The EPS were modified in different ways. EPS were carboxymethylated to obtain carboxymethyl-exopolysaccharides (CEPS). EPS and CEPS were doped with ammonium iodide and 1-butyl-3-methylimidazolium chloride. An α relaxation process was observed for all specimens. The temperature dependence of the relaxation times for pure and doped, EPS and CEPS polymers exhibited non-Arrhenius behavior. This relaxation process was associated with the glass transition of the complex heteropolysaccharides produced by the cyanobacteria. The molecular mobility at the glass transition, Tg, was affected by both the carboxymethylation treatment and the doping. The fragility index also decreased for the doped specimens, which may be attributed to an increase in the mobility of the polymer chains due to the plasticizing effect of the doping agents.

A simple method to produce Synechocystis PCC6803 biofilm under laboratory conditions for electron microscopic and functional studies.

Cyanobacteria can form biofilms in nature, which have ecological roles and high potential for practical applications. In order to study them we need biofilm models that contain healthy cells and can withstand physical manipulations needed for structural studies. At present, combined studies on the structural and physiological features of axenic cyanobacterial biofilms are limited, mostly due to the shortage of suitable model systems. Here, we present a simple method to establish biofilms using the cyanobacterium Synechocystis PCC6803 under standard laboratory conditions to be directly used for photosynthetic activity measurements and scanning electron microscopy (SEM). We found that glass microfiber filters (GMF) with somewhat coarse surface features provided a suitable skeleton to form Synechocystis PCC6803 biofilms. Being very fragile, untreated GMFs were unable to withstand the processing steps needed for SEM. Therefore, we used polyhydroxybutyrate coating to stabilize the filters. We found that up to five coats resulted in GMF stabilization and made possible to obtain high resolution SEM images of the structure of the surface-attached cells and the extensive exopolysaccharide and pili network, which are essential features of biofilm formation. By using pulse-amplitude modulated variable chlorophyll fluorescence imaging, it was also demonstrated that the biofilms contain photosynthetically active cells. Therefore, the Synechocystis PCC6803 biofilms formed on coated GMFs can be used for both structural and functional investigations. The model presented here is easy to replicate and has a potential for high-throughput studies.

Observation of exopolysaccharides (EPS) from Lactobacillus helveticus SBT2171 using the Tokuyasu method.

Some species of lactic acid bacteria used for the production of natural cheese produce exopolysaccharides (EPS). Electron microscopy is useful for analyzing the microstructure of EPS produced by lactic acid bacteria. However, pretreatments used to observe the microstructure of EPS by electron microscopy, such as dehydration and resin embedding, can result in EPS flowing out easily from the cell. Therefore, in this study, the Tokuyasu method was conducted on cryosection to reduce EPS outflow. Two types of observation method, namely, using lectin and ruthenium red, were conducted in an attempt to observe EPS produced by Lactobacillus helveticus SBT2171. Observation using the lectin method confirmed that colloidal gold particles conjugated with a lectin recognizing ß-galactoside were present in the capsule. Structures that appeared to be ß-galactoside-containing slime polysaccharides that were released from the cell wall were also observed. Observation using ruthenium red showed that capsular polysaccharides (CPS) in the capsule were present as a net-like structure. Colloidal gold conjugation with an anti-ß-lactoglobulin antibody, in addition to ruthenium red staining, allowed the identification of slime polysaccharides released from the cell wall in the milk protein network derived from the culture medium. Based on these results, the Tokuyasu method was considered to be a useful pretreatment method to clarify and observe the presence of EPS. In particular, both CPS in the capsule and slime exopolysaccharides released from the cell wall were visualized.

Preparation of thermally stable emulsion gels based on Glucono-δ-lactone induced gelation of gellan gum.

In this study, we investigated the gellan gelation mechanism induced by Glucono-δ-lactone (GDL) addition, and subsequently we further fabricated a series of thermally irreversible emulsion gels with the GDL-induced gel matrix as the continuous phase and the methyl cellulose (MC) stabilized emulsion as the dispersed phase. The results showed that GDL- induced gellan gelation was both a time- and temperature-dependent process, which was similar to the gelation process of NaCl-induced gellan gels, but with a higher temperature-dependence. Moreover, GDL-induced gel had a significantly higher rupture strength and the resulting gel did not melt on heating, meaning that the GDL-induced gellan gel can be deemed thermally irreversible. This is because decreasing pH is commonly more effective in promoting gellan gelation. Besides, by mixing the MC-stabilized emulsion with a hot gellan sol, followed by adding GDL, we fabricated the emulsion gels with a wide range of oil phase fraction (0-30%). The emulsion gels exhibited good thermal stability, without melting and oil droplet coalescence observed when heating the gels in a boiling water bath for 30 min. Conclusively, our results may deepen the understanding on gellan gelation induced by GDL and also broaden the utilization of gellan in building gel-related food structures.

Development of antioxidant and antimicrobial xanthan-based cryogels with tuned porous morphology and controlled swelling features.

Novel porous films based on xanthan gum (XG), poly(vinyl alcohol) (PVA), and red grape pomace (RGP), as entrapped natural antioxidant agent, were prepared by freeze/thawing, a versatile and non-destructive method. The stability of XG/PVA films was dependent on the crystalline zones created by PVA under freeze/thawing treatment. After three cryogenic cycles, the introduction of RGP into the 3D polymer matrix plays a major role by hindering the access of water into the cavities already formed during the first and second cryogenic cycles. By contrast, XG/PVA-based cryogels with enhanced mechanical strength were obtained when the number of freeze/thawing cycles increased from three to seven, while pores stability was improved by entrapment of RGP. The remarkable antioxidant and antimicrobial activity of XG/PVA/RGP cryogel films compared to the XG/PVA films, indicates the potential application of these systems in food packaging.

Influences of drying methods on the structural, physicochemical and antioxidant properties of exopolysaccharide from Lactobacillus helveticus MB2-1.

In this study, in order to evaluate influences of different drying methods on the structural characteristics, physicochemical properties and antioxidant activities of exopolysaccharides (EPS) from Lactobacillus helveticus MB2-1, three drying methods, including spray-drying (SD), freeze-drying (FD) and spray freeze-drying (SFD), were applied to dry EPS. Results showed that different drying procedures had no significant influence on the primary structure and constituent monosaccharides of EPSs. However, the surface morphology of the three dried EPSs varied greatly in size and shape due to different drying processes. Among three dried EPSs, the particle size distribution of spray freeze-dried EPS (SF-EPS) was relatively narrower and uniform. Additionally, SF-EPS behaved better apparent viscosity and emulsifying property than spray-dried EPS (S-EPS) and freeze-dried EPS (F-EPS). SF-EPS exhibited stronger antioxidant activities when compared with S-EPS and F-EPS, according to the results of scavenging activities on different radicals and chelating activity on ferrous ion. Overall, SFD was the appropriate method for industrial production of EPS from Lactobacillus helveticus MB2-1 with better physicochemical properties and antioxidant activities.

Interpenetrating network gels with tunable physical properties: Glucono-δ-lactone induced gelation of mixed Alg/gellan sol systems.

In this study, a class of interpenetrating network (IPN) gels were successfully fabricated based on glucono-δ-lactone (GDL) induced gelation of mixed alginate (Alg) and deacylated gellan (gellan) systems. The IPN gels were prepared by co-hydrating a mixed Alg and gellan powder, followed by adding GDL and calcium carbonate (CaCO3) in sequence to initiate the gelation. It was found that Alg and gellan can form independently a gel network, with no significant interaction between the two types of gel networks observed, as indicated by the results of gel strength determination, scanning electron microscope (SEM) observations and thermogravimetry (TG) and derivative thermogravimetric (DTG) analyses. Moreover, the mixing ratio of Alg to gellan significantly affected the physical properties of the fabricated gels. With increasing Alg to gellan ratio, the gels tended to become more elastic, and to show a higher rehydration rate and rehydration extent. Overall, these tunable properties may allow the fabricated gels to find potential applications in designing or optimizing the structures of gel-related food products.

Diversity of serotypes and new cps loci variants among Streptococcus suis isolates from pigs in Poland and Belarus.

Streptococcus suis plays an important role in infections in pigs but information about the epidemiology of this pathogen in Poland and Belarus remains scarce. Ninety-six isolates from brain and lungs were studied by PCR-based serotyping, analysis of virulence-associated determinants and multilocus sequence typing (MLST). Selected six isolates were further analyzed by genomic sequencing and transmission electron microscopy (TEM). Serotype 2 was most prevalent, followed by serotypes 3, 4, 8 and 7. All isolates carried fbpS; 30, 74 and 79 isolates were positive for epf, mrp and sao, respectively. MLST revealed that while widely distributed clonal complexes, such as 1, 16, 25 and 28 circulate in both countries, a significant part of the population is composed of novel singletons. Six isolates, all positive for the capsule in TEM, harbored cps loci differing to a various degree from these previously described, including one with a novel cps locus (putative NCL21). In conclusion, our study provides first molecular data on S. suis from pigs in the Central/Eastern Europe and contributes to a better characterization of diversity of loci responsible for capsule production in this pathogen.

Study of chitosan/xanthan gum polyelectrolyte complexes formation, solid state and influence on ibuprofen release kinetics.

This study investigated the combined influence of pH adjusting agent type (hydrochloric, acetic or lactic acid) and initial pH value (3.6, 4.6, and 5.6) on formation of biocompatible chitosan/xanthan polyelectrolyte complexes (PECs), their characteristics in solid state and influence on in vitro ibuprofen release kinetics. Conductivity measurements and rheological characterization revealed generally higher extent of ionic interactions in PEC dispersions comprising acetic acid and at pH 3.6. Acid type and pH affected significantly the yield and particle size (100-250 µm) of the dried PECs. Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (PXRD) analysis of the solid PECs confirmed exclusively physical (ionic, hydrogen bonds) interactions between chitosan and xanthan gum. PECs prepared with acetic acid at pH 4.6 and 5.6 had enhanced rehydration ability in phosphate buffer pH 7.2, and at PEC-to-drug mass ratio up to 1:2, enabled extended ibuprofen release from hard capsules during 10 h.

Structure-based glycoconjugate vaccine design: The example of Group B Streptococcus type III capsular polysaccharide.

Microbial surface polysaccharides are important virulence factors and targets for vaccine development. Glycoconjugate vaccines, obtained by covalently linking carbohydrates and proteins, are well established tools for prevention of bacterial infections. Elucidation of the minimal portion involved in the interactions with functional antibodies is of utmost importance for the understanding of their mechanism of induction of protective immune responses and the design of synthetic glycan based vaccines. Typically, this is achieved by combination of different techniques, which include ELISA, glycoarray, Surface Plasmon Resonance in conjunction with approaches for mapping at atomic level the position involved in binding, such as Saturation Transfer NMR and X-ray crystallography. This review provides an overview of the structural studies performed to map glycan epitopes (glycotopes), with focus on the highly complex structure of Group B Streptococcus type III (GBSIII) capsular polysaccharide. Furthermore, it describes the rational process followed to translate the obtained information into the design of a protective glycoconjugate vaccine based on a well-defined synthetic glycan epitope.

Improved exopolysaccharide production from Bacillus licheniformis MS3: Optimization and structural/functional characterization.

Exopolysaccharides (EPS) are microbially-originated, complex biosynthetic polymers, mainly carbohydrates in nature. They have gained attention of modern researches due to their novel physicochemical characteristics. However, the development of cost-effective strategies to improve the EPS yield, remains a challenge. In this study, cost-effective EPS production was carried out from B. licheniformis in solid state fermentation of mango peels substrate with waste-to-value theme. Initially, B. licheniformis was exposed to ultraviolet (UV) radiations of short wavelength which significantly improved the EPS yield (from 3.4 to 4.6 g/L). The highest EPS producing mutant strain (B. licheniformis MS3) was further proceeded for yield optimization using RSM-CCD approach. Optimization improved the yield >3.2-folds (from 4.6 to 15.6 g/L). The optimally yielded fraction was characterized using HPLC, FT-IR and SEM analyses. HPLC revealed the hetero-polymeric nature of EPS containing mannose (20.60%), glucose (46.80%), and fructose (32.58%) subunits. FT-IR spectroscopy revealed the presence of hydroxyl and carboxyl functional groups, and glycosidic linkages among monosaccharides. SEM microstructure showed that EPS comprise smoother surface with less porosity. Studies on functional characteristics revealed the presence of hydrophilic moieties among EPS with moderate water (105.3%) and oil (86.3%) uptake capacity. The EPS exhibited excellent emulsifying properties showed good stability against all hydrocarbons/oils tested. In conclusion, the cost-effective EPS production with multifunctional properties, this study may be valuable for various biochemical and biotechnological sectors.

Physicochemical and functional characterization of mannan exopolysaccharide from Weissella confusa MD1 with bioactivities.

The present study focused on production, optimization and characterization of exopolysaccharide (EPS) from Weissella confusa MD1. The purified EPS MD1 was also evaluated for in vitro biological activities. The maximum yield of EPS (10.07 ± 0.32 g/L) was obtained with optimized culture conditions of 35 °C at pH 6.5 for 36 h with 4% (w/v) galactose and 1% (w/v) ammonium nitrate supplemented in MRS broth. The crude EPS was purified with diethylamino ethanol-Sepharose Fast Flow column and Sephadex-G 75 column. The physicochemical and functional characterization of the EPS was done by high-performance thin-layer chromatography (HPTLC), high-performance gel permeation chromatography (HPGPC), fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), thermo gravimetric and differential scanning calorimetric (TG-DSC) analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM). HPGPC analysis showed molecular weight of purified EPS MD1 as 2.909 KDa. Monosaccharide analysis showed that EPS was a novel mannan with mannose as the only monomeric unit present, suggesting EPS to be a homopolysaccharide containing â†’ 6) α-Man p (1 â†’ linkages. Microstructure studies by SEM showed MD1 EPS has globular and porous structure. The purified EPS MD1 exhibited higher thermal stability having degradation temperature around 267.74 °C with melting enthalpy value (Δ H) of 337.7 J/g. The EPS showed promising antioxidant activities with excellent antibiofilm activity against Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica and Salmonella typhi. These striking physicochemical characteristics features and bioactivities of EPS would serve as potential candidate in food processing industry to be used as food adjunct in foods with health benefits. This is the first study reporting a mannan homopolysaccharide from Weissella sp. to be structurally characterized.

Bacterial Cellulose production by K. saccharivorans BC1 strain using crude distillery effluent as cheap and cost effective nutrient medium.

Bacterial Cellulose (BC), a valuable biopolymer gaining importance over the past few decades due to its remarkable properties and applications. In this study, crude distillery effluent having a high COD value of 87,433 mg/L was used to produce Bacterial Cellulose under static fermentation by Komagataeibacter saccharivorans, a novel isolated bacterial strain. 1.24 g/L of cellulose production was noted after eight days along with 23.6% reduction in COD value. The BC pellicle was purified, lyophilized and stored. Further, the lyophilized BC pellicle was subjected to characterization techniques such as SEM, ATR-FTIR, XRD, NMR and TLC. Morphological analysis revealed that cellulose fibers were dense with higher porosity and an average fiber width of 60 nm. FTIR depicted similar functional groups as that of BC-HS medium. TLC of the biopolymer was performed to evaluate its purity. X-ray diffraction and 13C NMR studies gave more insights about the crystalline and the amorphous regions; the synthesized polymer exhibited 80.2% as crystallinity and crystallite size of 8.36. Hence, the present study demonstrates that distillery effluent waters could be effectively reused as production medium fulfilling two objectives namely one reducing COD and making the effluent safe for disposal and two to produce a value-added product.

Exploring two contrasting surface-active exopolysaccharides from a single strain of Ochrobactrum utilizing different hydrocarbon substrates.

During production and characterization of exopolysaccharides (EPS) of Ochrobactrum pseudintermedium C1, it was observed that an experimental change in the basic hydrocarbon type of substrate for bacterial utilization led to elicitation of different surface-active properties in the EPS produced. In the sugar substrate, it elicited surfactant property, while in oil substrates it elicited emulsifying property, which indicated that the EPS might be different. Consequently, attention was focused on a detailed analysis of this substrate-specific EPS. Utilizing waste sugar, edible, and mineral oil substrates, EPS produced in each situation was characterized. Besides estimating surface activity and thermostability, each substrate-specific EPS was analyzed by Fourier-transform infrared spectroscopy, gas chromatography-mass spectroscopy, 1 H-nuclear magnetic resonance, and matrix-assisted laser desorption/ionization-time of flight mass spectroscopy to find any structural difference. The results were significantly contrasting although the similarity in molecular mass suggested a basic similarity in polysaccharide structure. Morphological differences were also evident both macroscopically and microscopically with scanning electron microscopy. As the surface-active property of EPS was dependent on the substrate utilized, their structural differences might account for it. These diverse surface activities of EPS produced by a single bacterial strain simply by changing the nature of substrate would also augment their bioapplications. Moreover, utilization of waste and easily available substrates should make such applications convenient, ecofriendly, and cost-worthy.

The relationship between the structural characteristics of lactobacilli-EPS and its ability to induce apoptosis in colon cancer cells in vitro.

Colon cancer is one of the most common cancer around the world. Exopolysaccharides (EPSs) produced by lactobacilli as potential prebiotics have been found to have an anti-tumor effect. In this study, lyophilized EPSs of four Lactobacillus spp. for their impact on apoptosis in colon cancer cells (HT-29) was evaluated using flow cytometry. The relationship between capability of a lactobacilli-EPS to induce apoptosis and their monosaccharide composition, molecular weight (MW), and linkage type was investigated by HPLC, SEC, and NMR, respectively. Changes in apoptotic-markers were examined by qPCR and Western Blotting. EPSs were capable of inhibiting proliferation in a time-dependent manner and induced apoptosis via increasing the expression of Bax, Caspase 3 and 9 while decreasing Bcl-2 and Survivin. All EPSs contained mannose, glucose, and N-acetylglucosamine with different relative proportions. Some contained arabinose or fructose. MW ranged from 102-104Da with two or three fractions. EPS of L. delbrueckii ssp. bulgaricus B3 having the highest amount of mannose and the lowest amount of glucose, showed the highest apoptosis induction. In conclusion, lactobacilli-EPSs inhibit cell proliferation in HT-29 via apoptosis. Results suggest that a relationship exists between the ability of EPS to induce apoptosis and its mannose and glucose composition.