imagine (Institute of molecular genetics and genetic engineering)
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The route to transcription initiation determines the mode of transcriptional bursting in E. coli
Get PDFTranscription is fundamentally noisy, leading to significant heterogeneity across bacterial populations. Noise is often attributed to burstiness, but the underlying mechanisms and their dependence on the mode of promotor regulation remain unclear. Here, we measure E. coli single cell mRNA levels for two stress responses that depend on bacterial sigma factors with different mode of transcription initiation (sigma (70) and sigma (54)). By fitting a stochastic model to the observed mRNA distributions, we show that the transition from low to high expression of the sigma (70)-controlled stress response is regulated via the burst size, while that of the sigma (54)-controlled stress response is regulated via the burst frequency. Therefore, transcription initiation involving sigma (54) differs from other bacterial systems, and yields bursting kinetics characteristic of eukaryotic systems. Transcription noise in bacteria is often attributed to burstiness, but the mechanisms are unclear. Here, the authors show that the transition from low to high expression can be regulated via burst size or burst frequency, depending on the mode of transcription initiation determined by different sigma factors
Isolation of high-quality RNA from recalcitrant leaves of variegated and resurrection plants
No full textResurrection plant Ramonda serbica is a suitable model to investigate mechanisms of desiccation tolerance, while variegated Pelargonium zonale has been proven to serve as an excellent model for the metabolite allocation between sink tissue and source tissue within the same organ. However, the genomes of these plants are still not sequenced, limiting their application in molecular studies. To investigate the transcript abundance by next-generation sequencing, high-quality RNA input is required. Leaves of both P. zonale and R. serbica are rich in polyphenols that interfere with high-quality RNA extraction by common protocols. Moreover, low water content and high amount of sugars and other osmoprotectants in desiccated R. serbica leaves present the additional challenge in total RNA extraction. Here, we evaluated and compared several already established TRIzol- and CTAB-based protocols aiming to develop the efficient, simple and low-cost methods for the extraction of the satisfactory yield RNA of great purity and integrity, required for the construction of high-quality cDNA libraries. Our results show that the CTAB-based protocol (i.e. CTAB 1b) enabled the extraction of high-quality RNA from photosynthetically active and non-photosynthetically active leaf sectors of P. zonale, with high RIN values. On the other hand, TRIzol-based protocol provided a high RNA yield with low contamination and high RNA integrity even in desiccated leaves of R. serbica. We envisage that the proposed protocol would be suitable for the RNA extractions from other desiccated organs (e.g. seeds, grains, pollen grains)
Neovascularization Effects of Carbon Monoxide Releasing Drugs Chemisorbed on Coscinodiscus Diatoms Carriers Characterized by Spectromicroscopy Imaging
Get PDFSilica microparticles made of diatomaceous earth have become particularly attractive materials for designing drug delivery systems. In order to investigate the use of natural diatoms as drug scaffolds for carbon monoxide releasing molecules (CORMs), we evaluated the chemisorption of the cis-[Re(CO)(2)Br-4](2-) complex (ReCORM-2) and its vitamin B-12 derivative (B-12-ReCORM-2) on Coscinodiscus frustules by 3D FT-IR spectroscopic imaging, and the drugs' neovascularization effects in vivo in the zebrafish (Danio rerio) model. By mapping the symmetric Re-C equivalent to O upsilon(CO) stretching vibration of the CORMs in the 2000 cm(-1) region, we found that the drugs are mostly localized at the girdle band of the diatom frustule. Both ReCORM-2 and B-12-ReCORM-2 retain their CO-releasing ability when chemisorbed on the diatoms. When applied in vivo at doses gt = 25 mu M, the molecules markedly reduced intersegmental and subintestinal vessels development in zebrafish, revealing high anti-angiogenic potential. In addition, diatom frustules did not provoke any toxic in vivo response in the zebrafish embryos, including inflammation. Overall, our results indicate that: (1) CORMs chemisorbed on diatom frustules retain their CO-releasing abilities; (2) both CO-releasing molecules show a concentration-dependent effect on the neovascularization in developing zebrafish; (3) silicate frustules are not toxic and could be used as CORMs drug carriers
Yogurt Produced by Novel Natural Starter Cultures Improves Gut Epithelial Barrier In Vitro
No full textYogurt is a traditional fermented dairy product, prepared with starter cultures containing Streptococcus thermophilus and Lactobacillus bulgaricus that has gained widespread consumer acceptance as a healthy food. It is widely accepted that yogurt cultures have been recognized as probiotics, due to their beneficial effects on human health. In this study, we have characterized technological and health-promoting properties of autochthonous strains S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 isolated from artisanal sour milk and yogurt, respectively, in order to be used as functional yogurt starter cultures. Both BGKMJ1-36 and BGVLJ1-21 strains have the ability to form curd after five hours at 42 degrees C, hydrolyze alpha(s1)-, beta-, and kappa- casein, and to show antimicrobial activity toward Listeria monocytogenes. The strain BGKMJ1-36 produces exopolysaccharides important for rheological properties of the yogurt. The colonies of BGKMJ1-36 and BGVLJ1-21 strains that successfully survived transit of the yogurt through simulated gastrointestinal tract conditions have been tested for adhesion to intestinal epithelial Caco-2 cells. The results reveal that both strains adhere to Caco-2 cells and significantly upregulate the expression of autophagy-, tight junction proteins-, and anti-microbial peptides-related genes. Hence, both strains may be interesting for use as a novel functional starter culture for production of added-value yogurt with health-promoting properties
Novel antimicrobial nanocomposite based on polypropylene non-woven fabric, biopolymer alginate and copper oxides nanoparticles
No full textThe objective of this study was to develop novel antimicrobial nanocomposite material based on polypropylene (PP) non-woven fabric, biopolymer alginate and copper oxides nanoparticles. In order to introduce polar groups onto the surface of PP fibers necessary for binding of alginate, non-woven fabric was activated by corona discharge. Carboxylate groups of alginate were further utilized for binding of Cu2+-ions which were reduced with sodium borohydride as a conventional and ascorbic acid as a green reducing agent. Characteristic morphological and chemical changes induced by corona activation and alginate impregnation were confirmed by FTIR, XPS and FESEM analyses. AAS measurements showed that the amounts of generated nanoparticles depend on applied reducing agent and the concentration of precursor salt. XPS analysis suggested that nanoparticles were mixture of copper (I) and (II) oxides. XPS depth profiling gave an exceptional insight into chemical changes within the thin layer on the fiber surface and formation of certain interfaces induced by each treatment. All fabricated nanocomposites provided excellent antimicrobial activity against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and yeast C. albicans. The cytotoxicity assay indicated that maximum amount of Cu2+-ions released from synthetized nanocomposite within 24 h was not cytotoxic to human keratinocyte (HaCaT) cells
Structural characterization and biological evaluation of polynuclear Mn (II) and Cd(II) complexes with 2,2-dimethyl-1,3-propanediamine-N,N,N ', N '-tetraacetate. The influence of ligand structure and counter cation on the complex nuclearity
No full textNew polynuclear manganese(II) and cadmium(II) complexes with 2,2-dimethyl-1,3-propanediamine-N,N, N',N'-tetraacetato ligand (2,2-diMe-1,3-pdta), {Ba[M(2,2-diMe-1,3-pdta)]center dot 3H(2)O}(n) (M = Mn (1) or Cd (2)) were synthesized and characterized by IR spectroscopy and single-crystal X-ray diffraction analysis. In addition, complex 2 was characterized by solution H-1 and C-13 NMR spectroscopy. Crystallographic analysis showed that 2,2-diMe-1,3-pdta ligand is hexadentately coordinated to each M(II) ion through the two nitrogen and four carboxylate oxygen atoms, whereas the one of these oxygen atoms is also involved in coordination to the second M(II) ion of the dinuclear [M-2(2,2-diMe-1,3-pdta)(2)](4-) unit in polymeric structures. Moreover, three of four carboxylic groups of 2,2-diMe-1,3-pdta ligand are additionally bonded to four Ba(II) ions, in three distinctive bridging coordination modes. Each Ba(II) ion is surrounded by ten oxygen atoms, seven belonging to carboxylate groups of 2,2-diMe-1,3-pdta, and three belonging to water molecules. The coordination environment around Mn(II) and Cd(II) ions could be assigned as a face capped octahedron, while coordination polyhedron around Ba(II) ion in these two complexes was described as a distorted sphenocorona. The antimicrobial potential of complexes 1 and 2 and corresponding metal salts used for their synthesis was evaluated against different bacterial and Candida spp. Both complexes showed selective antifungal activity against the tested Candida spp. compared to the bacterial strains, with the minimal inhibitory concentration (MIC) values in the range 3.12 - 12.50 mu M. Moreover, complex 1 caused the slightly decrease of hyphae length, while no significant influence on hyphal length of complex 2 was observed. With aim to assess the therapeutic profile of the complexes, their cytotoxicity was evaluated against the normal human lung fibroblast cell line (MRC-5)
Molecular Diagnostics of Cystic Fibrosis in Serbia: Our Approach to Meet the Diagnostic Challenges
No full textBackground: High heterogeneity levels of cystic fibrosis transmembrane regulator (CFTR) are manifested in different populations. The aim of this study was to analyze comprehensively all mutations in the CFTR gene in Serbian patients with cystic fibrosis (CF) and to use the findings to propose a testing algorithm for the Serbian population. Materials and Methods: Cascade screening was employed to detect mutations in the CFTR gene of 90 patients suspected of having CF, using polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism or PCR-mediated site directed mutagenesis, Sanger sequencing, and/or next-generation sequencing. Results: This is the first report for the Serbian CF population where single nucleotide polymorphisms, small insertions and deletions, large genome rearrangements, and copy number variants were analyzed in detail. A high degree of heterogeneity within the CFTR was documented among our cohort of 90 patients. We identified 19 CF-causing mutations and 3 with varying consequences, including a previously unreported deletion of the entire exon 11. Conclusion: Considering the spectrum and frequency of mutations found, we recommend a multistep sequencing algorithm in combination with evaluation of large rearrangements for future analyses of the CFTR gene in the Serbian population
Lactolisterin BU-producer Lactococcus lactis subsp. lactis BGBU1-4: Biocontrol of Listeria monocytogenes and Staphylocococcus aureus in fresh soft cheese and effect on immunological response of rats
No full textIn last two decades, there has been a strong trend in the application of lactic acid bacteria as adjunctive cultures to control growth of spoilage and pathogenic bacteria in food. One of the most important properties that contribute to the application of these bacteria is the production of antimicrobial molecules. Lactococcus lactis subsp. lactis BGBU1-4, isolated from traditional brined cheese, produces thermostable bacteriocin named lactolisterin BU, with broad spectrum of activity against spoilage bacteria and foodborne pathogens. In this study, effect of strain BGBU1-4, as adjunct culture, on the numbers of Listeria monocytogenes ATCC19111 and Staphylococcus aureus LMM322 in artificially contaminated Quark-type, soft acid coagulated cheese, was examined. In addition, we analyzed influence of BGBU1-4 on chemical and sensory properties of the cheese, as well as immunological response of Albino oxford rats fed with Quark-type of cheese made using BGBU1-4 as adjunct culture. Results of this study revealed antibacterial potential of strain BGBU1-4 against L. monocytogenes ATCC19111 and S. aureus LMM322 in Quark-type cheese during 21 days of storage at 4 degrees C. Also, it was noticed the ability of BGBU1-4 to control the spontaneously grown yeasts and molds. Chemical composition and pH values of cheese containing BGBU1-4 were unchanged in comparison to control. The sensory quality scores showed that there was difference between cheese with and without adjunct culture in terms of flavor and oral texture, while for the odor and appearance no differences between two cheese variants were scored. Results of the immunological response of Albino rats fed with Quark-type cheese containing BGBU1-4 indicate absence of systematic inflammation. However, increased pro-inflammatory cytokines content (IL-1 beta, IL-6, IL-17) in intestine of rats fed with cheese containing BGBU1-4, concomitantly with unchanged anti-inflammatory cytokines suggests disruption of gut homeostasis and inflammation in this tissue. The changes caused by BGBU1-4 are reversible, system returns into homeostasis seven days after cessation of feeding with cheese containing BGBU1-4
