RSC Advances

doi: 10.1039/c3ra90055jpmid: N/A

doi: 10.1039/c3ra90056hpmid: N/A

Bankar, Sandip B.; Singhal, Rekha S.

doi: 10.1039/c3ra22596hpmid: N/A

Poly-ε-lysine (ε-PL), (S)-poly(imino(2-amino-1-oxo-1,6-hexanediyl)), is a naturally occurring homopolymer of l-lysine with a degree of polymerization of 25–35, and characterized by peptide bonds between the carboxyl and ε-amino groups of l-lysine. ε-PL is currently receiving much attention due to its wide applications in chemical, pharmaceutical, food, medical, clinical chemistry, biotechnology and other industries. Moreover, it is water-soluble, biodegradable, heat stable, edible and nontoxic towards humans. The present review discusses the production, recovery, characterization, biodegradation and applications of ε-PL. Production of ε-PL by fermentation is detailed, along with its industrial problems such as biodegradation. Various purification techniques for higher recovery of ε-PL are also described here. Issues of ε-PL degrading enzyme and its characterization studies have also been addressed. Molecular genetics as a tool for development of highly productive strains is also discussed herein. Applications of ε-PL in various industries showed to have an increasing impact on bioprocessing.

Chatterjee, Pradeep K.; Shakes, Leighcraft A.; Wolf, Hope M.; Mujalled, Mohammad A.; Zhou, Constance; Hatcher, Charles; Norford, Derek C.

doi: 10.1039/c3ra40332gpmid: 24772295

Bacterial Artificial Chromosomes (BACs) are large pieces of DNA from the chromosomes of organisms propagated faithfully in bacteria as large extra-chromosomal plasmids. Expression of genes contained in BACs can be monitored after functionalizing the BAC DNA with reporter genes and other sequences that allow stable maintenance and propagation of the DNA in the new host organism. The DNA in BACs can be altered within its bacterial host in several ways. Here we discuss one such approach, using Tn10 mini-transposons, to introduce exogenous sequences into BACs for a variety of purposes. The largely random insertions of Tn10 transposons carrying lox sites have been used to position mammalian cell-selectable antibiotic resistance genes, enhancer-traps and inverted repeat ends of the vertebrate transposon Tol2 precisely at the ends of the genomic DNA insert in BACs. These modified BACs are suitable for expression in zebrafish or mice, and have been used to functionally identify important long-range gene regulatory sequences in both species. Enhancer-trapping using BACs should prove uniquely useful in analyzing multiple discontinuous DNA domains that act in concert to regulate expression of a gene, and is not limited by genome accessibility issues of traditional enhancer-trapping methods.

Giustini, Mauro; Giuliani, Anna Maria; Gennaro, Giuseppe

doi: 10.1039/c3ra23208epmid: N/A

In this review some aspects of the interactions of organized structures of amphiphiles with natural or synthetic DNAs are briefly considered. In particular DNAs encapsulated in closed cavities of amphiphiles, specifically giant vesicles and water-in-oil droplets and reverse micelles, are dealt with. Two main applications of giant vesicles are reviewed in detail, namely their use as microreactors where reactions can be followed by optical microscopy on a single vesicle and in synthetic biology as protocell models or as potential semi-synthetic “living” cells. Water-in-oil droplets uses for rapid and relatively low-cost DNA amplification by PCR reaction are described as well as for in vitro transcription and translation. A large variety of non-Watson–Crick conformations of polynucleotides observed in the aqueous inner core of reverse micelles is illustrated and compared with those observed in matched water solutions.

Wang, Xin-Ping; Yin, Bin-Cheng; Ye, Bang-Ce

doi: 10.1039/c3ra23296dpmid: N/A

We have developed a facile and label-free method for sequence-specific microRNA detection using fluorescent dsDNA-templated copper nanoclusters as signal indicators. It is designed such that, the miRNA targets are transferred to the oligonucleotide reporters and act as the scaffold for the synthesis of fluorescent copper nanoclusters via an isothermal exponential amplification reaction, in which the unimolecular DNA designed for miRNA targets is employed as the amplification template with polymerases and nicking enzymes as mechanical activators. Under the selected conditions, the proposed assay allowed sensitive and selective detection of miRNAs with a linear range from 1 pM to 10 nM.

Paul, Sanjay; Pal, Gargi; Das, Asish R.

doi: 10.1039/c3ra40571kpmid: N/A

A highly convergent, efficient and practical heteroannulation protocol for the synthesis of a library of coumarin and uracil fused pyrrole derivatives has been developed. Reactions involving the CuFe2O4 catalyzed one-pot three-component domino coupling of 6-aminouracil/4-aminocoumarin, aldehydes and nitromethane resulted in highly substituted coumarin and uracil fused pyrrole derivatives, making this strategy very useful in diversity-oriented synthesis (DOS). CuFe2O4 magnetic nanoparticles were prepared by a simple and effective citric acid complex method and characterized by using XRD, FT-IR, and TEM images. The easy recovery of the catalyst and high yield of the products makes the protocol attractive, sustainable and economic. The catalyst was recycled for six cycles with almost unaltered catalytic activity.

Li, Haibo; Wu, Xiaofu; Xu, Bowei; Tong, Hui; Wang, Lixiang

doi: 10.1039/c3ra40901epmid: N/A

Stable blue emissive hyperbranched conjugated polymer nanoparticles with tunable particle sizes were synthesized by Suzuki polymerization in miniemulsion, which could be facile soluble in common organic solvents after complete removal of surfactants. As highly sensitive fluorescent probes for picric acid, they exhibit 25 times higher fluorescence quenching ability and 100 times wider linear detection region (from 1.0 nM to 4.0 μM) compared to their linear conjugated polymer nanoparticle analogue.

Kundu, Shrishnu Kumar; Mitra, Kanchan; Majee, Adinath

doi: 10.1039/c3ra40509epmid: N/A

Indium triflate catalyzed selective mono-N-alkylation of primary amines is reported using dialkyl phosphite as an alkylating agent under microwave irradiation. The mono-N-alkyl selectivity is largely accelerated when the conventional heating was replaced by the “greener” microwave irradiation. The overall procedure is operationally simple, mild, eco-friendly and straightforward.

Lv, Jinpeng; Li, Chundong; BelBruno, J. J.

doi: 10.1039/c3ra40837jpmid: N/A

Understanding the influences of lattice defect evolution on the optical properties of ZnO is of significance. To clarify this, we adopted typical treatments on ZnO using Al–H co-doping and post-annealing, combined with comprehensive characterization (absorption spectrum, Raman scattering, photoluminescence, electronic paramagnetic resonance and positron annihilation). The results reveal that the visible luminescence can arise from the VO, VZn and AlZn–Oi defects, while the defect centers responsible for the blue band optical absorption are assigned to ionized Zni and V+O. SEM images illustrated that H+ implantation diluted the ZnAl2O4 second phase, which reaccumulated after O2 annealing.