imagine (Institute of molecular genetics and genetic engineering)
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Medium chain length (mcl)-pha-based nanocomposites for biomedical applications: system evaluation through xrd
Get PDFMedium-chain polyhydroxyalkanoates (mcl-PHA) are flexible, elastomeric polymers produced by wide range of
bacteria as intercellular storage of carbon and energy. They represent attractive components in biomaterial design
because they are biocompatible, biodegradable and can be obtained using variety of carbon sources including
waste streams[1]. However, being semi-crystalline, all mcl-PHAs are characterized by low melting temperature and
poor tensile strength which can interfere with processing methods and wider biomedical application. Simple way
to improve mcl-PHAs properties is to incorporate a nanophase within biopolymer to obtain nanocomposites.
Nano-sized constituents interact with biopolymer more intimately affecting in turn the obtained nanocomposite
properties as well as functionality. Among inorganic nanofillers, TiO2 nanostructures with high aspect ratio (e.g.
nanofibers) have unique properties that support osteogenic phenotype which makes them suitable for bone tissue
engineering [2]
Lactic Acid Bacteria in the Gut
No full textIn the complex ecosystem of gut microbiota, lactic acid bacteria (LAB)+B represent prevalent, abundant, and highly important subpopulation. LAB+B are well-known for their health-promoting effects: they are found to positively influence gut microbiota diversity, modulate immune response and intestinal permeability, and produce bioactive or regulatory metabolites. Bifidobacteriaceae represent critical early colonizers of the human gut, and the depletion of this microbial group in infants is correlated with allergy development. LAB+B are considered as one of the first human gut colonizers and recent studies have shown that humans might be exposed to them even in the womb. The primary role of the human gut microbiota, as in other animals, is its contribution to digestion. Several types of health-promoting dietary polyphenols are able to boost the abundance of LAB+B in human trials, but also in in vitro tests and animal models. A molecular methods-based insight into gut microbiota diversity showed presence of its disturbed composition-dysbiosis-in various diseases
IL-28B genotypes as predictors of long-term outcome in patients with hepatitis C-related severe liver injury
Get PDFIntroduction: Patients with severe fibrosis or cirrhosis are at high risk for liver-related complications, even after successful antiviral treatment and/or regression of fibrosis. These are the first published results concerning the role of IL-28B genotypes as predictors of the durability of sustained virological response (SVR) and long-term outcome, in patients with baseline severe fibrosis and cirrhosis caused by hepatitis C (HCV) infection. Methodology: Genetic testing for three different single nucleotide polymorphisms (SNP) near the IL28B gene, rs12979860, rs12980275 and rs8099917, was performed in 42 patients with HCV-related advanced fibrosis and cirrhosis, who achieved SVR after successful interferon-based treatment. Baseline clinical and laboratory parameters were analysed, as well as IL28B genotype association with late virological relapse, fibrosis progression and clinical outcomes. Results: The most prevalent genotypes in all three tested SNP positions were: CCrs12979860 genotype in 69% of patients, GT(rs)(8099917) in 78.6% and GG(rs)(12980275) in 47.6% of patients. The presence of IL28B CCrs12979860 genotype was identified as a negative predictor of late virological relapse. Further analysis did not confirm the association of other IL28B genotypes with the progression of fibrosis and clinical outcomes. Conclusions: Varying long-term prognosis in patients with HCV-related severe fibrosis and cirrhosis is due to multiple interactions between host genetic factors, virus and environment. These are first published results demonstrating the significance of IL28B CCrs12979860 genotype as a negative predictor of late virological relapse. A further investigation concerning genetic factors is necessary to identify patients under risk for late relapse, complications and unfavorable outcomes, so that they can be reevaluated and offered new treatment options
Macroscopic optical and diffraction assessment of encrustations and SEM analyses of phototrophic microbial mats from wellheads and select zones of emergence of mineral water in Serbia
Get PDFInvestigations focusing on wellhead encrustations within select zones of emergence of mineral water, in different hydrogeological provinces, were conducted from 2014 to 2017 in Serbia. They included: well BB-1 in Bogatic (Inner Dinaric Alps of western Serbia), wells LB-4 and LB-5 in Lukovska Banja (Sumadija-Kopaonik-Kosovo Province), and wells VG-2 and VG-3 in Vranjska Banja (Serbian Crystalline Core). The studied occurrences belong to the group of hot mineral waters, with temperatures ranging from 62 degrees C to 93.9 degrees C, and total dissolved solids (TDS) from 600 to 1267 mg/L. They are mildly acidic to mildly alkaline (pH 6.6 -8.0) and their genetic types are HCO3--Na++K+ (Bogatic and Lukovska Banja) and SO42-, HCO3--Na++K+ (Vranjska Banja). Macroscopic, optical and diffraction assessment revealed that the encrustations comprised calcite and aragonite minerals, along with some local quartz, muscovite, albite and clinochlore. The conclusion was that there was a predominant presence of calcium carbonate in all the occurrences, represented by crystalline calcite grains, characteristically birefractive, and dark, semi-translucent grains in the form of microcrystalline calcite highly stained by iron hydroxides (Bogatic), as well as crystalline calcite with radially developed carbonate - aragonite (Lukovska Banja) and rod-like and filamentous aggregates of aragonite and calcite, highly translucent in places (Vranjska Banja). The texture of the samples exhibits alternating horizontal or wavy carbonate laminae. In Vranjska Banja, they include thin micritic to medium crystalline laminae and laminae composed of aggregates of aragonite needles in the form of bunch. In Bogatic and Lukovska Banja, there are thick micritic and highly porous laminae, 0.025 to 1 mm thick, or interlayers of a coarser crystalline structure. Apart from encrustations, all the occurrences exhibit phototrophic microbial mats, which were analyzed by scanning electron microscopy. The onset and progress of encrustation are primarily influenced by the physical and chemical composition of the mineral water (T, pH, TDS, HCO3-, Ca2+, CO2, etc.), as corroborated by hydrogeochemical modeling software PHREEQC 3.4.0. In addition, phototrophic biofilms might be contributing to the creation and accumulation of minerals in the encrustations
Lactococcin B Is Inactivated by Intrinsic Proteinase PrtP Digestion in Lactococcus lactis subsp. lactis BGMN1-501
Get PDFIn our previous study we demonstrated that proteinase PrtP is able to impair bacteriocin LcnB activity, despite being produced by the same organism and encoded by the same plasmid. However, precise mechanism of this action, i.e., the exact cleavage site within LcnB bacteriocin, as well as its effect on antimicrobial activity of the resulting peptide remained vague. Here we further explored the interplay between these two proteins and defined, using mass spectrometry, that this unusual hydrolysis indeed occurs in vivo, between the sixth and seventh amino acid on the N terminus of LcnB. To address whether the cleaved form of LcnB retains any level of activity, both recombinant and chemically synthesized variant of truncated LcnB were engineered and produced, but demonstrated no antimicrobial activity. When LcnB was recombinantly overexpressed and subjected to PrtP digestion, the change in its antimicrobial activity was monitored and the degradation products analyzed with reverse-phase high-pressure liquid chromatography. The results confirmed the inactivity of the truncated LcnB and additionally corroborated the PrtP cleavage site in LcnB bacteriocin. In addition, it was demonstrated that, once truncated, LcnB is not able to bind its receptor and is susceptible to additional hydrolysis. This is the first report on proteolytic inactivation of bacteriocins inside the same bacterial host
In Vitro and In Vivo Biocompatibility of Novel Zwitterionic Poly(Beta Amino)Ester Hydrogels Based on Diacrylate and Glycine for Site-Specific Controlled Drug Release
No full textNew (beta-aminoester) hydrogels (PBAE) based on di(ethylene glycol)diacrylate and glycine are successfully synthesized and characterized for the first time in this work. PBAE macromers are obtained using Michael addition. By changing the diacrylate/amine stoichiometric ratio, but maintaining it gt 1, samples with different chemical structure containing acrylate end-groups are obtained. The hydrogels are synthesized from macromers utilizing free radical polymerization. Chemical structure of macromers and hydrogels is confirmed by proton nuclear magnetic resonance, and Fourier transform infra-red spectroscopy. Swelling and degradation rates in physiological pH range change notably with pH and monomer molar ratio, validating pH sensitivity and zwitterionic behavior, which can be finely tuned by changing any of these parameters. In vitro cytotoxicity and in vivo acute embryotoxicity in zebrafish (Danio rerio) performed to assess the biocompatibility of the novel hydrogel materials and their degradation products reveal that materials are nontoxic and biocompatible. The Cephalexin in vitro drug release study, at pH values 2.20, 5.50, and 7.40, demonstrates pH-sensitive delivery with the release profiles effectively controlled by pH and the hydrogel composition. PBAE hydrogels exhibit great potential for a variety of biomedical applications, including tissue regeneration and intelligent drug delivery systems
PsrA Regulator Connects Cell Physiology and Class 1 Integron Integrase Gene Expression Through the Regulation of lexA Gene Expression in Pseudomonas spp.
No full textPseudomonas aeruginosa, which is a clinically important representative of Pseudomonas spp., has been recognized as causative agent of severe nosocomial infections worldwide. An increase in antibiotic resistance of P. aeruginosa clinical strains could be attributed to their capacity to acquire resistance through mobile genetic elements such as mobile integrons that are present in one-half of multidrug-resistant P. aeruginosa strains. Mobile class 1 integrons are recognized as genetic elements involved in the rapid dissemination of multiple genes encoding for antibiotic resistance. The LexA protein is a major repressor of integrase transcription, but differences in transcription regulation among bacterial species have also been noted. In this study, the promoter activity of class 1 integron integrase gene (intI1) and its variant lacking the LexA binding site in Pseudomonas putida WCS358 wild type, rpoS and psrA was analysed. The results show that the activity of the intI1 gene promoter decreased in the rpoS and psrA mutants in the stationary phase of growth compared to the wild type, which indicates the role of RpoS and PsrA proteins in the positive regulation of integrase transcription. Additionally, it was determined that the activity of the lexA gene promoter decreased in rpoS and psrA, and thus, we propose that PsrA indirectly regulates the intI1 gene promoter activity through regulation of lexA gene expression in co-operation with some additional regulators. In this study, intI1 gene expression was shown to be controlled by two major stress response (SOS and RpoS) regulons, which indicates that integrase has evolved to use both systems to sense the cell status
Oral neonatal antibiotic treatment perturbs gut microbiota and aggravates central nervous system autoimmunity in Dark Agouti rats
Get PDFGut microbiota dysbiosis has been considered the essential element in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Antibiotics were administered orally to Dark Agouti (DA) rats early in their life with the aim of perturbing gut microbiota and investigating the effects of such intervention on the course of EAE. As a result, the diversity of the gut microbiota was reduced under the influence of antibiotics. Mainly, Firmicutes and Actinobacteria were replaced by Proteobacteria and Bacteroidetes, while decreased proportions of Clostridia and Bacilli classes were accompanied by an increase in Gamma-Proteobacteria in antibiotic-treated animals. Interestingly, a notable decrease in the Helicobacteraceae, Spirochaetaceae and Turicibacteriaceae was scored in antibiotic-treated groups. Also, levels of short chain fatty acids were reduced in the faeces of antibiotic-treated rats. Consequently, aggravation of EAE, paralleled with stronger immune response in lymph nodes draining the site of immunization, and increased inflammation within the CNS, were observed in antibiotic-treated DA rats. Thus, the alteration of gut microbiota leads to an escalation of CNS-directed autoimmunity in DA rats. The results of this study indicate that antibiotic use in early life may have subsequent unfavourable effects on the regulation of the immune system
The Influence of Heat-Killed Enterococcus faecium BGPAS1-3 on the Tight Junction Protein Expression and Immune Function in Differentiated Caco-2 Cells Infected With Listeria monocytogenes ATCC 19111
Get PDFListeria monocytogenes, the common foodborne pathogenic bacteria species, compromises the intestinal epithelial barrier, leading to development of the listeriosis, a severe disease especially among immunocompromised individuals. L. monocytogenes infection usually requires antibiotic treatment, however, excessive use of antibiotics promotes emergence of antibiotic resistance and the destruction of gut microbiota. Probiotics, including lactic acid bacteria (LAB), have been repeatedly proven as an alternative approach for the treatment of various infections. We have analyzed the potential of Enterococcus faecium BGPAS1-3, a dairy isolate exhibiting strong direct antilisterial effect, to modulate the response of differentiated Caco-2 intestinal epithelial cells to L. monocytogenes ATCC 19111 infection. We showed that the molecule with antilisterial effect is a bacterial cell-wall protein that is highly resistant to the high-temperature treatment. When we tested the antilisterial potential of heat-killed BGPAS1-3, we found that it could prevent tight junction disruption in differentiated Caco-2 monolayer infected with L. monocytogenes ATCC 19111, induce antilisterial host response mechanisms, and stimulate the production of protective TGF-beta in intestinal epithelial cells. We also showed that the modulation of MyD88 dependent TLR2 and TLR4 pathways by BGPAS1-3 are involved in host response against L. monocytogenes ATCC 19111. Since heat-killed BGPAS1-3 possess strong antilisterial effects, such postbiotic could be used as a controllable and safe therapeutic
Cytotoxic Activity of Riccardin and Perrottetin Derivatives from the Liverwort Lunularia cruciata
No full textSeven new bisbibenzyls (1-7) were isolated from the methanol extract of the liverwort Lunularia cruciata along with one previously known bibenzyl and five known bisbibenzyls. The structures of compounds 1-7 were elucidated on the basis of the spectroscopic data, These newly isolated bisbibenzyls may be divided into two groups, the acyclic bisbibenzyls, perrottetins (1-3), and the cyclic analogues, riccardins (4-7). Besides standard perrottetin and riccardin structures (1 and 4, respectively), they contain phenanthrene (3 and 5), dihydrophenanthrene (2), and quinone moieties (6 and 7), rarely found in natural products. The new compounds 3 and 5, as well as the known riccardin G, exhibited cytotoxic activity against the A549 lung cancer cell line with IC50 values of 5.0, 5.0, and 2.5 mu M, respectively