Frontispiece: Process Development for Separation of Conformers from Derivatives of Resorcin[4]arenes and Pyrogallol[4]arenes (original) (raw)
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International Journal of Molecular Sciences
Microbial infections remain a global health concern, calling for the urgent need to implement effective prevention measures. Antimicrobial peptides (AMPs) have been extensively studied as potential antimicrobial coating agents. However, an efficient and economical method for AMP production is lacking. Here, we synthesized the direct coating adhesive AMP, NKC-DOPA5, composed of NKC, a potent AMP, and repeats of the adhesive amino acid 3,4-dihydroxyphenylalanine (DOPA) via an intein-mediated protein ligation strategy. NKC was expressed as a soluble fusion protein His-NKC-GyrA (HNG) in Escherichia coli, comprising an N-terminal 6× His-tag and a C-terminal Mxe GyrA intein. The HNG protein was efficiently produced in a 500-L fermenter, with a titer of 1.63 g/L. The NKC-thioester was released from the purified HNG fusion protein by thiol attack and subsequently ligated with chemically synthesized Cys-DOPA5. The ligated peptide His-NKC-Cys-DOPA5 was obtained at a yield of 88.7%. The purifi...
Sustainability
There is a growing recognition that an advanced understanding of the trophic characteristics of an invasive consumer can provide important information on its ecological impact. In recent years, the blue swimming crab Portunus segnis, one of the earliest Lessepsian invaders, has considerably expanded its distribution range in the Mediterranean Sea, yet, its trophic habits in invaded areas remain scarcely investigated. In this study, we used carbon and nitrogen stable isotopes analysis (SIA) to determine the trophic position and isotopic niche of the crab compared with other representatives of the flora and fauna occurring in Elounda Bay (Crete). P. segnis showed a trophic position of 3.9, higher than the values determined by SIA or conventional gut content analysis in other areas of the Mediterranean Sea or in the native range. Crab specimens showed a high inter-individual variability in both δ13C and δ15N values; further analysis indicated negligible differences in the isotopic nich...
Journal of the American Chemical Society, 2015
Manganese(IV,V) hydroxo and oxo complexes are often implicated in both catalytic oxygenation and water oxidation reactions. Much of the research in this area is designed to structurally and/or functionally mimic enzymes. On the other hand, the tendency of such mimics to decompose under strong oxidizing conditions makes the use of molecular inorganic oxide clusters an enticing alternative for practical applications. In this context it is important to understand the reactivity of conceivable reactive intermediates in such an oxide-based chemical environment. Herein, a polyfluoroxometalate (PFOM) mono-substituted with manganese, [NaH2(Mn-L)W17F6O55]q-, has allowed the isolation of a series of compounds, Mn(II, III, IV and V), within the PFOM framework. Magnetic susceptibility measurements show that all the compounds are high spin. XPS and XANES measurements confirmed the assigned oxidation states. EXAFS measurements indicate that Mn(II)PFOM and Mn(III)PFOM have terminal aqua ligands an...
Streptococcus pneumoniae (Spn) must acquire iron from the host to establish infection. We examined the impact of hemoglobin, the largest iron reservoir in the body, on pneumococcal physiology. Supplementation with hemoglobin allowed Spn to resume growth in an iron-deplete medium. pneumococcal growth with hemoglobin was unusually robust, exhibiting a prolonged logarithmic growth, higher biomass, and extended viability in both iron-deplete and standard medium. We observed the hemoglobin-dependent response in multiple serotypes, but not with other host proteins, free iron, or heme. Remarkably, hemoglobin induced a sizable transcriptome remodeling, effecting virulence and metabolism in particular genes facilitating host glycoconjugates use. Accordingly, Spn was more adapted to grow on the human α − 1 acid glycoprotein as a sugar source with hemoglobin. A mutant in the hemoglobin/heme-binding protein Spbhp-37 was impaired for growth on heme and hemoglobin iron. the mutant exhibited reduced growth and iron content when grown in tHYB and hemoglobin. In summary, the data show that hemoglobin is highly beneficial for Spn cultivation in vitro and suggest that hemoglobin might drive the pathogen adaptation in vivo. the hemoglobin receptor, Spbhp-37, plays a role in mediating the positive influence of hemoglobin. These novel findings provide intriguing insights into pneumococcal interactions with its obligate human host. Streptococcus pneumoniae (Spn) is a significant human pathogen that causes illnesses ranging in severity from common otitis media infections to invasive diseases such as pneumonia, bacteremia, and meningitis. Pneumo-coccal pneumonia is also a significant risk factor for the development of cardiac diseases and heart failure 1,2. Altogether, the toll of Spn on human health is substantial, and the pathogen is responsible for ~ 15 million infections each year and about half a million deaths in children worldwide 3,4. Pneumococci commonly colonize the human nasopharynx, and Spn can persist asymptomatically in healthy individuals for several weeks and up to a few months 5. From the nasopharynx, Spn can be transmitted among hosts 6 and spread to other organs. Young children (< 5 years of age), the elderly, and immunocompromised persons are the most susceptible individuals to pneumococcal infections 7-9. While colonization of the upper respiratory tract is a prerequisite for pneumo-coccal pathogenesis and infectivity, the factors that govern the establishment of Spn in the human host and the pathogen's transition into a virulent state, are not fully appreciated. Healthy individuals typically avoid infection by S. pneumoniae. Still, the opportunistic pathogen can thrive in susceptible hosts and cause serious ailments. S. pneumoniae, though, is a fastidious bacterium that in vitro exhibits relatively weak growth. Several studies were undertaken to optimize streptococcal cultivation in a complex open
Langmuir, 2012
Nanostructured soft matter systems represent effective and long-lasting solutions with respect to traditional and often obsolete methodologies for the conservation of works of art. In particular, complex fluids such as micelles and microemulsions are the most performing media for the removal of organic materials from porous supports, like wall paintings or stones. In this Article, we report on the characterization of two systems, EAPC and XYL, which have shown good to optimal performances in the removal of organic polymers from wall paintings. EAPC is a five-components fluid composed of water, sodium dodecylsulfate (SDS), 1-pentanol (PeOH), propylene carbonate (PC), and ethyl acetate (EA), while XYL is a "classical" o/w microemulsion, where p-xylene droplets are stabilized in water by SDS and PeOH. Small-angle neutron scattering (SANS) with contrast variation is used to infer a detailed picture of the structure of these complex fluids, with a particular focus on the partition of the components between the bulk phase and the nanocompartments. We found that, differently from XYL, the EAPC system is neither a microemulsion nor a simple micellar solution, with the cosolvents partitioned between the dispersing phase and the disperse droplets. These different structural features play a key role in defining the cleaning effectiveness and specifically the kinetics of interaction between the nanofluid and the polymeric coating to be removed, which is of paramount importance for the application in the field. Both of these nanofluids are effective in polymer removal, but EAPC is considerably more efficient and versatile. The composition and the structure at the nanoscale determine the capability of removing a broad range of different polymer coatings from porous materials. A representative case study is here described, addressing a particularly challenging conservative issue, which is the removal of a multilayered aged coating that was irreversibly damaging the pictorial layer of the Annunciation Basilica in Nazareth.
para-Selective Cyanation of Arenes by H-Bonded Template
2019
The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work we demonstrate the para-selective introduction of versatile nitrile moiety, enabled by detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools heralds the inception of para-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications