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Antibacterial glycopeptides isolated from insects are exciting bio-oligomers because they represent a family of compounds in which the structural and functional effects of incorporating short O-linked sugars to protein fragments c...
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Antibacterial glycopeptides isolated from insects are exciting bio-oligomers because they represent a family of compounds in which the structural and functional effects of incorporating short O-linked sugars to protein fragments can be studied. Additionally, their high activity in vitro warrants detailed further drug development efforts. Due to the limited availability of the isolated material, we used synthetic glycopeptides and some analogs to investigate the range of activity of drosocin and pyrrhocoricin. While addition of the Gal-GalNAc disaccharide to the natural mid-chain position generally increased the antibacterial activity of drosocin, pyrrhocoricin lacking sugar appeared to be more potent, with an IC50 against Escherichia coli D22 of 150 nM. Although glycosylated drosocin was active against E. coli in the low microM range in vitro, this peptide was completely inactive when injected into mice. The lack of in vivo activity of drosocin could be explained by the unusually high degradation rate of the peptides in mammalian sera. The early degradation products were inactive in vitro. In contrast, the peptides were considerably more stable in insect hemolymph, where their natural activity is manifested.
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The first chemical synthesis of 1′-deoxy-1′-fluorosucrose has been accomplished in eight steps from sucrose by an unlikely, but ultimately successful, S_N2 displacement reaction.
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1,1,1,3,3,3-Hexafluoro-2-propanol is introduced as a suitable reagent and solvent for the detritylation of 5'-O-(4,4'-dimethoxytrityl)-nucleosides and -deoxynucleosides, especially those that are susceptible to N-glycosyl cleavage...
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1,1,1,3,3,3-Hexafluoro-2-propanol is introduced as a suitable reagent and solvent for the detritylation of 5'-O-(4,4'-dimethoxytrityl)-nucleosides and -deoxynucleosides, especially those that are susceptible to N-glycosyl cleavage under more strongly acidic conditions. [References: 13]
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Background: Silver nanoparticles (AgNPs), are amongst the utmost striking nanosizedmaterials that are extensively applied in a variety of biomedical applications whichincludes diagnostic use, disease management, medical device coa...
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Background: Silver nanoparticles (AgNPs), are amongst the utmost striking nanosizedmaterials that are extensively applied in a variety of biomedical applications whichincludes diagnostic use, disease management, medical device coating, drug delivery and forpersonal health care.Discussion: With the growing interest and its application in the health care sector, it is becomingnecessary for a better understanding and exploration of AgNPs mechanism of actionlike biological interaction, their possible toxicity, and safety concern to human exposure.AgNPs have been the subject of researchers attention and interest due to the uniqueproperties and quality such as shape and size depending optical, electrical, and antimicrobialpotentials (antibacterial, antifungal, antiviral etc.). In recent times, several studies havebeen conducted on AgNPs antimicrobial potential and also a number of patents related to itssynthesis, clinical role and importance have also been registered. In this review, a shortoverview of AgNPs synthesis approach is presented (physical, chemical, and biological orgreen synthesis) and it also delivers a historical outlook of AgNPs application as an antimicrobialagent which includes combined evidence of microbial resistance and safety issueswith human exposure.
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A new series of ferrocenyl diamino alcohols and diamines were synthesized and their inhibitory potencies were probed with Mycobacterium tuberculosis. Interestingly, ferrocenyl diamines 6a and b display significant activities again...
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A new series of ferrocenyl diamino alcohols and diamines were synthesized and their inhibitory potencies were probed with Mycobacterium tuberculosis. Interestingly, ferrocenyl diamines 6a and b display significant activities against M. tuberculosis H37Rv.
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ObjectiveBifunctional alpha-bisabolol and phenylethyl resorcinol/TiO2 hybrids were prepared to apply in cosmetic fields, particularly in anti-ageing and hyperpigmentation treatment. The synergistic effect of combined antioxidant a...
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ObjectiveBifunctional alpha-bisabolol and phenylethyl resorcinol/TiO2 hybrids were prepared to apply in cosmetic fields, particularly in anti-ageing and hyperpigmentation treatment. The synergistic effect of combined antioxidant and UV filtering properties was achieved through functionalization of TiO2 particles with skin-lightening materials such as alpha-bisabolol and phenylethyl resorcinol.
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This review focuses on chemical ligation methods for the preparation of oligopeptides and proteins. Chemical ligation is a practical and convenient methodology in peptide and protein synthesis. Longer peptides and proteins can be ...
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This review focuses on chemical ligation methods for the preparation of oligopeptides and proteins. Chemical ligation is a practical and convenient methodology in peptide and protein synthesis. Longer peptides and proteins can be obtained with high yield in aqueous buffer solutions by coupling unprotected peptide segments even without activation by enzymes or further chemical agents. Several methods and protocols were developed in the past. The potential of the most important approaches of the thioester- and imine-ligation techniques is demonstrated by a broad spectrum of applications. In addition, special features and protocols such as the template-directed ligation, ligation with novel additives or solvent media, microwave-assisted ligation, and the achievements obtained with those are also highlighted herein.
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The divergent synthesis of branched DNA (bDNA) comb structures is described. This new type of bDNA contains one unique oligonucleotide, the primary sequence, covalently attached through a comb-like branch network to many identical...
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The divergent synthesis of branched DNA (bDNA) comb structures is described. This new type of bDNA contains one unique oligonucleotide, the primary sequence, covalently attached through a comb-like branch network to many identical copies of a different oligonucleotide, the secondary sequence. The bDNA comb structures were assembled on a solid support and several synthesis parameters were investigated and optimized. The bDNA comb molecules were characterized by polyacrylamide gel electrophoretic methods and by controlled cleavage at periodate-cleavable moieties incorporated during synthesis. The developed chemistry allows synthesis of bDNA comb molecules containing multiple secondary sequences. In the accompanying article we describe the synthesis and characterization of large bDNA combs containing all four deoxynucleotides for use as signal amplifiers in nucleic acid quantification assays.
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Well-defined amphiphilic block copolymers poly(styrene-b-acrylic acid) (PS-b-PAA) with controlled block length were synthesized using atom transfer radical polymerization (ATRP). Pectinase enzyme was immobilized on the well-define...
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Well-defined amphiphilic block copolymers poly(styrene-b-acrylic acid) (PS-b-PAA) with controlled block length were synthesized using atom transfer radical polymerization (ATRP). Pectinase enzyme was immobilized on the well-defined amphiphilic block copolymers PS-b-PAA. The carboxyl groups on the amphiphilic PS-b-PAA diblock copolymers present a very simple, mild, and time-saving process for enzyme immobilization. Various characteristics of immobilized pectinase such as the pH and temperature stability, thermal stability, and storage stability were valuated. Among them the pH optimum and temperature optimum of free and immobilized pectinase were found to be pH 6.0 and 65 degrees C.
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The purpose of this Review is 2-fold: (1) to compile and discuss catalytic, asymmetric chemical syntheses of β-lactams and (2) to gather other recently published synthetic methods spanning from 2008 to 2013, as an extension of th...
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The purpose of this Review is 2-fold: (1) to compile and discuss catalytic, asymmetric chemical syntheses of β-lactams and (2) to gather other recently published synthetic methods spanning from 2008 to 2013, as an extension of the Chemical Reviews article by Brandi, Cicchi, and Cordero. The scope of this Review is limited to novel synthetic assembly of the β- lactam (2-azetidinone) ring; for information on the synthesis and biological activity of monocyclic β-lactams and carbapenems, 5 the synthesis and biological activity of cephems, oxacephems, penams, and sulbactam, the use of β-lactams in the synthesis of non-β-lactam products, mechanisms and applications of β-lactam biosynthesis, combinatorial approaches to the synthesis of β-lactams, classic modification or total synthesis of β-lactam antibiotics, or books on either synthetic approaches to or a physical organic discussion of β-lactams, see attached references. Additionally, some other pertinent reviews are attached to the subtitles in section 3.
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