The New Methodology and Chemical Contrast Observation by Use of the Energy-Selective Back-Scattered Electron Detector

Bacteria degrading both n-alkanes and aromatic hydrocarbons are prevalent in soils

This study was undertaken to determine the distribution of soil bacteria capable of utilizing both n-alkanes and aromatic hydrocarbons. These microorganisms have not been comprehensively investigated so far. Ten contaminated (4046-43,861 mg of total petroleum hydrocarbons (TPH) kg-1 of dry weight of soil) and five unpolluted (320-2754 mg TPH kg-1 of dry weight of soil) soil samples from temperate, arid, and Alpine soils were subjected to isolation of degraders with extended preferences and shotgun metagenomic sequencing (selected samples). The applied approach allowed to reveal that (a) these bacteria can be isolated from pristine and polluted soils, and (b) the distribution of alkane monooxygenase (alkB) and aromatic ring hydroxylating dioxygenases (ARHDs) encoding genes is not associated with the contamination presence. Some alkB and ARHD genes shared the same taxonomic affiliation; they were most often linked with the Rhodococcus, Pseudomonas, and Mycolicibacterium genera. Moreover, these taxa together with the Paeniglutamicibacter genus constituted the most numerous groups among 132 culturable strains growing in the presence of both n-alkanes and aromatic hydrocarbons. All those results indicate (a) the prevalence of the hydrocarbon degraders with extended preferences and (b) the potential of uncontaminated soil as a source of hydrocarbon degraders applied for bioremediation purposes.

The Impact of Exosomes/Microvesicles Derived from Myeloid Dendritic Cells Cultured in the Presence of Calcitriol and Tacalcitol on Acute B-Cell Precursor Cell Lines with MLL Fusion Gene

Vitamin D analogs (VDAs) may directly inhibit the growth of normal and malignant (derived from acute lymphoblastic leukemia (ALL)) B cells, as both types of cells express vitamin D receptor (VDR). We performed anti-proliferative, morphology tests and phenotyping to evaluate the sensitivity of monocytes and iDCs (immature myeloid-derived dendritic cells) on calcitriol and tacalcitol treatment, phenotyping, morphology, and size distribution measurement to determine the characteristics of microvesicles (MVs) and exosomes (EXs) derived from them and, finally, phenotyping and Elisa test to determine the effects of VDAs on modulation of the phenotype of B cells through extracellular vesicles (EVs) released by iDCs. Our results confirmed that both SC cells and iDCs were sensitive to the VDAs and showed altered surface expression of markers associated with monocyte differentiation, which was resulting in the phenotypic changes in EVs derived from them. We also showed that obtained EVs could change the morphology and phenotype of ALL-B-derived precursor cells in a different way, depending on their origin. The differential effect of VDAs on ALL-B cells, which was associated with increased or decreased expression of CD27, CD24, CD38, and CD23 expression, was observed. Hence, further studies to explain the modulation in the composition of EVs by VDAs are required.

New Peptide Based Fluconazole Conjugates with Expanded Molecular Targets

Infections of Candida spp. etiology are frequently treated with azole drugs. Among azoles, the most widely used in the clinical scenario remains fluconazole (FLC). Promising results in treatment of dangerous, systemic Candida infections demonstrate the advantages of combined therapies carried out with combinations of at least two different antifungal agents. Here, we report five conjugates composed of covalently linked FLC and cell penetrating or antimicrobial peptide: TP10-7-NH₂, TP10-NH₂, LFcinB(2-11)-NH₂, LFcinB[Nle^1,11]-NH₂, and HLopt2-NH₂, with aspects of design, chemical synthesis and their biological activities. Two of these compounds, namely FLCpOH-TP10-NH₂ and FLCpOH-TP10-7-NH₂, exhibit high activity against reference strains and fluconazole-resistant clinical isolates of C. albicans, including strains overproducing drug transporters. Moreover, both of them demonstrate higher fungicidal effects compared to fluconazole. Analysis performed with fluorescence and scanning electron microscopy as well as flow cytometry indicated the cell membrane as a molecular target of synthesized conjugates. An important advantage of FLCpOH-TP10-NH₂ and FLCpOH-TP10-7-NH₂ is their low cytotoxicity. The IC₉₀ value for the human cells after 72 h treatment was comparable to the MIC₅₀ value after 24 h treatment for most strains of C. albicans. In reported conjugates, FLC was linked to the peptide by its hydroxyl group. It is worth noting that conjugation of FLC by the nitrogen atom of the triazole ring led to practically inactive compounds. Two compounds produced by us and reported herein appear to be potential candidates for novel antifungal agents.

Conjugation of Meningococcal Lipooligosaccharides Through Their Non-Reducing Terminus Results in Improved Induction a Protective Immune Response

The present studies prove that conjugation of meningococcal lipooligosaccharides through their non-reducing terminus conserves their inner epitopes resulting in conjugates potent to induce a protective immune response. Four different oligosaccharides were obtained by specific degradations of the same L7 lipooligosaccharide (L7-LOS), and each was linked to tetanus toxoid by direct reductive amination. Two were truncated oligosaccharides with incomplete inner epitopes and were obtained by mild acid hydrolysis of lipooligosaccharide. The terminal galactose of one oligosaccharide was additionally enzymatically oxidized. These oligosaccharides were conjugated through a newly exposed terminal Kdo in reducing end or through oxidized galactose localized at non-reducing end of the core, respectively. The third was a full-length oligosaccharide obtained by O-deacylation of the L7-LOS and subsequent enzymatic removal of phosphate substituents from its lipid A moiety. The fourth one was also a full-length O-deacylated lipooligosaccharide, but treated with galactose oxidase. This allowed direct conjugation to tetanus toxoid through terminal 2-N-acyl-2-deoxy-d-glucopyranose or through oxidized galactose, respectively. Comparison of the immune performance of four conjugates in mice revealed, that while each was able to induce significant level of L7-LOS-specific IgG antibody, the conjugates made with the full-length saccharides were able to induce antibodies with increased bactericidal activity against homologous meningococci. Only full-length oligosaccharides were good inhibitors of the binding of L7-LOS to the bactericidal antiserum. Moreover, induction of the significant level of the L7-LOS-specific antibody by full-length lipooligosaccharide conjugated from non-reducing end, provided also the direct evidence that internal core epitopes are fully responsible for the immunorecognition and immunoreactivity.

Biocompatible Carbon-Based Coating as Potential Endovascular Material for Stent Surface

Stainless steel 316L is a material commonly used in cardiovascular medicine. Despite the various methods applied in stent production, the rates of in-stent restenosis and thrombosis remain high. In this study graphene was used to coat the surface of 316L substrate for enhanced bio- and hemocompatibility of the substrate. The presence of graphene layers applied to the substrate was investigated using cutting-edge imaging technology: energy-filtered low-voltage FE-SEM approach, scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). The potential of G-316L surface to influence endothelial cells phenotype and endothelial-to-mesenchymal transition (EndoMT) has been determined. Our results show that the bio- and hemocompatible properties of graphene coatings along with known radial force of 316L make G-316L a promising candidate for intracoronary implants.

Effectiveness of Sensors Contact Metallization (Ti, Au, and Ru) and Biofunctionalization for Escherichia coli Detection

In designing a bacteria biosensor, various issues must be addressed: the specificity of bacteria recognition, the immobilization of biomolecules that act as the bacteria receptor, and the selectivity of sensor surface. The aim of this paper was to examine how the biofunctionalized surface of Ti, Au, and Ru metals reacts in contact with strains of Escherichia coli (E. coli). The focus on metal surfaces results from their future use as electrodes in high frequency biosensors, e.g., resonant circuits or transmission-line sections. First, the surfaces of different metals were chemically functionalized with 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde or with 3-glycidylooxypropyltrimethoxysilane (GPTMS) followed by N-(5-amino-1-carboxypentyl) iminodiacetic acid (AB-NTA) and NiCl₂. Secondly, the lipopolysaccharide binding protein (LBP), polyclonal anti-Escherichia coli antibody and bacteriophage protein gp37 were tested as bacteria receptors. The selectivity and specificity have been confirmed by the Enzyme-Linked Immunosorbent Assay (ELISA) and visualized by scanning electron microscopy at low landing energies. We noticed that LBP, polyclonal antibody, and gp37 were successfully immobilized on all studied metals and recognized the E. coli bacteria selectively. However, for the antibody, the highest reactivity was observed when Ti surface was modified, whereas the bacteria binding was comparable between LBP and gp37 on the functionalized Ru surfaces, independent from modification. Thus, all surfaces were biocompatible within the scope of biosensor functionality, with titanium functionalization showing the best performance.

Structural elucidation of Tsukamurella pulmonis neutral polysaccharide and its visualization in infected mouse tissues by specific monoclonal antibodies

Tsukamurella pulmonis is an opportunistic actinomycetal pathogen associated with a variety of rarely diagnosed human infections. In clinical cases of infection, T. pulmonis usually accompanies other bacterial pathogens. Because of these mixed infections, a robust diagnostic assay is important. The bacteria cell surface polysaccharides are considered not only useful targets for diagnostics but also intriguing subjects for analysis of the interactions that regulate the host response in general. Here, the structure of the polysaccharide component of the T. pulmonis cell wall was established. Sugar and methylation analysis and 2D-NMR techniques revealed that its polysaccharide belongs to the class of arabinomannan composed of branched tetrasaccharide repeating units, with addition of linear →6)-α-D-Manp-(1→ mannan. Rabbit polyclonal sera against T. pulmonis and T. paurometabola bacterial cells revealed cross reactivity between their antigens. Tissue samples from mice infected with T. pulmonis revealed liver abscesses and pathologic granules located intracellularly when immunohistochemically stained with monoclonal antibodies raised against T. pulmonis polysaccharide. Ultrastructural studies revealed that these granules contain T. pulmonis cells. These observations indicate that T. pulmonis is a pathogenic species capable of spreading within the organism, presumably through the blood.

Aggregation/dispersion transitions of T4 phage triggered by environmental ion availability

Background

Bacteriophage survives in at least two extremes of ionic environments: bacterial host (high ionic-cytosol) and that of soil (low ionic-environmental water). The impact of ionic composition in the micro- and macro-environments has not so far been addressed in phage biology.

Results

Here, we discovered a novel mechanism of aggregation/disaggregation transitions by phage virions. When normal sodium levels in phage media (150 mM) were lowered to 10 mM, advanced imaging by scanning electron microscopy, atomic force microscopy and dynamic light scattering all revealed formation of viral packages, each containing 20–100 virions. When ionic strength was returned from low to high, the aggregated state of phage reversed to a dispersed state, and the change in ionic strength did not substantially affect infectivity of the phage. By providing the direct evidence, that lowering of the sodium ion below the threshold of 20 mM causes rapid aggregation of phage while returning Na⁺ concentration to the values above this threshold causes dispersion of phage, we identified a biophysical mechanism of phage aggregation.

Conclusions

Our results implicate operation of group behavior in phage and suggest a new kind of quorum sensing among its virions that is mediated by ions. Loss of ionic strength may act as a trigger in an evolutionary mechanism to improve the survival of bacteriophage by stimulating aggregation of phage when outside a bacterial host. Reversal of phage aggregation is also a promising breakthrough in biotechnological applications, since we demonstrated here the ability to retain viable virion aggregates on standard micro-filters.