Polymer based bioadhesive biomaterials for medical application—a perspective of redefining healthcare system management

This article deliberates about the importance of polymer-based bioadhesive biomaterials’ medical application in healthcare and in redefining healthcare management. Nowadays, the application of bioadhesion in the health sector is one of the great interests for various researchers, due to recent advances in their formulation development. Actually, this area of study is considered as an active multidisciplinary research approach, where engineers, scientists (including chemists, physicists, biologists, and medical experts), material producers and manufacturers combine their knowledge in order to provide better healthcare. Moreover, while discussing the implications of value-based healthcare, it is necessary to mention that health comprises three main domains, namely, physical, mental, and social health, which not only prioritize the quality healthcare, but also enable us to measure the outcomes of medical interventions. In addition, this conceptual article provides an understanding of the consequences of the natural or synthetic polymer-based bioadhesion of biomaterials, and its significance for redefining healthcare management as a novel approach. Furthermore, the research assumptions highlight that the quality healthcare concept has recently become a burning topic, wherein healthcare service providers, private research institutes, government authorities, public service boards, associations and academics have taken the initiative to restructure the healthcare system to create value for patients and increase their satisfaction, and lead ultimately to a healthier society. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Ministry of Education, Youth and Sports of the Czech Republic-DKRVO [RP/CPS/2020/005]; COST ActionEuropean Cooperation in Science and Technology (COST) [CA 15216

Brevibacillus themoruber: a promising microbial cell factory for exopolysaccharide production

AimsThis study aims to identify a high level exopolysaccharide (EPS) producer thermophile that in turn could be used as a model organism to study the biological mechanisms and whole genome organization of EPS-producing thermophilic bacteria. Methods and ResultsThermophilic isolates were screened, and then growth and EPS production of the best producer Brevibacillus thermoruber strain 423 were investigated under different carbon and nitrogen sources, temperature, pH and agitation rates. Rheological characterization revealed that the EPS behaved like a typical Newtonian fluid and viscosity of the EPS solution increased with increasing Ca2+ ion concentration. Chemical characterization by TLC, GC-MS, FT-IR and NMR suggested a heteropolymer structure with glucose as major monomer unit. High biocompatibility of pure EPS fractions suggested their potential use in biomedical applications. ConclusionsThis study reports on the comprehensive description of microbial production conditions as well as chemical, rheological and biological characterization of the EPS produced by B.thermoruber strain 423. The bioreactor cultures were found to reach two times higher yields and three times higher productivities when compared with literature. Significance and Impact of the StudyBrevibacillus thermoruber strain 423 combined the advantages of its nonpathogenicity with the advantages of fast productivity and hence proved to be a very promising model organism and cell factory for microbial EPS production

Fructans Prime ROS Dynamics and Botrytis cinerea Resistance in Arabidopsis

Naturally derived molecules can be used as priming or defense stimulatory agents to protect against biotic stress. Fructans have gained strong interest due to their ability to induce resistance in a number of crop species. In this study, we set out to establish the role of fructan-induced immunity against the fungal pathogen Botrytis cinerea in Arabidopsis thaliana. We show that both inulin- and levan-type fructans from different sources can enhance Arabidopsis resistance against B. cinerea. We found that inulin from chicory roots and levan oligosaccharides from the exopolysaccharide-producing bacterium Halomonas smyrnensis primed the NADPH-oxidase-mediated reactive oxygen species (ROS) burst in response to the elicitors flg22, derived from the bacterial flagellum, and oligogalacturonides (OGs), derived from the host cell wall. Neither induced a direct ROS burst typical of elicitors. We also found a primed response after infection with B. cinerea for H2O2 accumulation and the activities of ascorbate peroxidase and catalase. Sucrose accumulated as a consequence of fructan priming, and glucose and sucrose levels increased in fructan-treated plants after infection with B. cinerea. This study shows that levan-type fructans, specifically from bacterial origin, can prime plant defenses and that both inulin and levan oligosaccharide-mediated priming is associated with changes in ROS dynamics and sugar metabolism. Establishing fructan-induced immunity in Arabidopsis is an important step to further study the underlying mechanisms since a broad range of biological resources are available for Arabidopsis

A genome-scale metabolic network of the aroma bacterium Leuconostoc mesenteroides subsp. cremoris

Leuconostoc mesenteroides subsp. cremoris is an obligate heterolactic fermentative lactic acid bacterium that is mostly used in industrial dairy fermentations. The phosphoketolase pathway (PKP) is a unique feature of the obligate heterolactic fermentation, which leads to the production of lactate, ethanol, and/or acetate, and the final product profile of PKP highly depends on the energetics and redox state of the organism. Another characteristic of the L. mesenteroides subsp. cremoris is the production of aroma compounds in dairy fermentation, such as in cheese production, through the utilization of citrate. Considering its importance in dairy fermentation, a detailed metabolic characterization of the organism is necessary for its more efficient use in the industry. To this aim, a genome-scale metabolic model of dairy-origin L. mesenteroides subsp. cremoris ATCC 19254 (iLM.c559) was reconstructed to explain the energetics and redox state mechanisms of the organism in full detail. The model includes 559 genes governing 1088 reactions between 1129 metabolites, and the reactions cover citrate utilization and citrate-related flavor metabolism. The model was validated by simulating co-metabolism of glucose and citrate and comparing the in silico results to our experimental results. Model simulations further showed that, in co-metabolism of citrate and glucose, no flavor compounds were produced when citrate could stimulate the formation of biomass. Significant amounts of flavor metabolites (e.g., diacetyl and acetoin) were only produced when citrate could not enhance growth, which suggests that flavor formation only occurs under carbon and ATP excess. The effects of aerobic conditions and different carbon sources on product profiles and growth were also investigated using the reconstructed model. The analyses provided further insights for the growth stimulation and flavor formation mechanisms of the organism

High bioreactor production and emulsifying activity of an unusual exopolymer by Chromohalobacter canadensis 28

Unusual composition of an exopolymer (EP) from an obligate halophilic bacterium Chromohalobacter canadensis 28 has triggered an interest in development of an effective bioreactor process for its production. Its synthesis was investigated in 2-L bioreactor at agitation speeds at interval 600-1000 rpm, at a constant air flow rate of 0.5 vvm; aeration rates of 0.5, 1.0, and 1.5 vvm were tested at constant agitation rate of 900 rpm. EP production was affected by both, agitation and aeration. As a result twofold increase of EP yield was observed and additionally increased up to 3.08 mg/mL in a presence of surfactants. For effective scale-up of bioreactors mass transfer parameters were estimated and lowest values of K(L)a obtained for the highest productivity fermentation was established. Emulsification activity of EP exceeded that of trade hydrocolloids xanthan, guar gum, and cellulose. A good synergism between EP and commercial cellulose proved its potential exploration as an enhancer of emulsifying properties of trade emulsions. A pronounced lipophilic effect of EP was established toward olive oil and liquid paraffin. Cultivation of human keratinocyte cells (HaCaT) with crude EP and purified gamma-polyglutamic acid (PGA) showed higher viability than control group

The fructan syndrome: Evolutionary aspects and common themes among plants and microbes

Fructans are multifunctional fructose-based water soluble carbohydrates found in all biological kingdoms but not in animals. Most research has focused on plant and microbial fructans and has received a growing interest because of their practical applications. Nevertheless, the origin of fructan production, the so-called fructan syndrome, is still unknown. Why fructans only occur in a limited number of plant and microbial species remains unclear. In this review, we provide an overview of plant and microbial fructan research with a focus on fructans as an adaptation to the environment and their role in (a)biotic stress tolerance. The taxonomical and biogeographical distribution of fructans in both kingdoms is discussed and linked (where possible) to environmental factors. Overall, the fructan syndrome may be related to water scarcity and differences in physicochemical properties, for instance, water retaining characteristics, at least partially explain why different fructan types with different branching levels are found in different species. Although a close correlation between environmental stresses and fructan production is quite clear in plants, this link seems to be missing in microbes. We hypothesize that this can be at least partially explained by differential evolutionary timeframes for plants and microbes, combined with potential redundancy effects. The capacity to biosynthesize fructans, fructose-based oligo and polysaccharides, is scattered over certain plant and microbial families. This review represents the first attempt to grasp the overall meaning of the fructan syndrome, crossing plants and microbes. By highlighting functional similarities and differences, this review prepares the ground for further research in plants and microbes, with focus on water scarcity and fructan signalling as common themes

Improving the catalytic behaviors of Lactobacillus-derived fructansucrases by truncation strategies

Fructansucrases (FSs), including inulosucrase (IS) and levansucrase (LS), are the members of the Glycoside Hydrolase family 68 (GH68) enzymes. IS and LS catalyze the polymerization of the fructosyl moiety from sucrose to inulin- and levan-type fructans, respectively. Lactobacillus-derived FSs have relatively extended N- and Cterminal sequences. However, the functional roles of these sequences in their enzymatic properties and fructan biosynthesis remain largely unknown. Limosilactobacillus reuteri (basionym: Lactobacillus reuteri) 121 could produce both IS and LS, abbreviated as Lare121-IS and Lare121-LS, respectively. In this study, it was found that the terminal truncation displayed an obvious effect on their activities and the N-terminal truncated variants, Lare121-IS Delta 177-701 and Lare121-LS Delta 154-686, displayed the highest activities. Melting temperature (Tm) and the thermostability at 50 degrees C were measured to evaluate the stability of various truncated versions, revealing the different effects of N-terminal on the stability. The average molecular weight and polymerization degree of the fructans produced by different truncated variants did not change considerably, indicating that N-terminal truncation had low influence on fructan biosynthesis. In addition, it was found that N-terminal truncation could also improve the activity of other reported FSs from Lactobacillus species

Improved Exopolymer Production by Chromohalobacter canadensis Cultures for Its Potential Cosmeceutical Applications

Several exopolymers with different chemical composition and correspondingly variety in their physico-chemical properties from halophilic microorganisms have still been described, however, with a low production yield. Chromohalobacter canadensis 28 isolated from Pomorie saltern synthesized an unusual exopolymer (EP) containing 72% gamma-polyglutamic acid (PGA), an essential cosmeceutical additive. Current work suggests a novel approach for effective EP synthesis by C. canadensis 28 using continuous cultures. Highest production was observed at low dilution rates reaching a level of 2.1 mg/mL at D = 0.035, similar to those in batch cultures (2.34 mg/mL), however avoiding all disadvantages of discontinuous fermentation processes. At steady state, the total quantities of the synthesized EP after 48 h cultivation for the given equipment volume in D = 0.035 h(-1) and D = 0.075 h(-1) were 8.67 and 12 g, correspondingly, while it was 2.9 g for batch culture. Process parameters did not change after a ten-day run at D = 0.35 h(-1). A degree of purity of EP fraction received from continuous cultures was significantly increased up to 93-96%. A lack of cytotoxicity and high cell viability were observed for human dermal fibroblast cells after 24 h incubation with crude EP from C. canadensis 28 and purified PGA fraction that could suggest its high potential for cosmetic applications