A novel luminescent functionalized siloxane polymer

The simple chemical reaction between acetone and tetrachlorosilane is found to yield a functionalized siloxane polymer that can emit light under normal conditions, if irradiated with a suitable wavelength. In situ multinuclear NMR spectra during various stages of the reaction show the formation of intermediates such as mesityl oxide (MeO), diacetone alcohol (DAA), phorone, isophorone, etc. Thus, the reaction is initiated via a type of self-condensation of acetone in the presence of tetrachlorosilane. The reaction provides a strongly acidic dehydrating atmosphere, which can be generated otherwise only in the presence of a specific catalyst and or at high temperatures. The reaction of the keto group with SiCl<SUB>4</SUB> is known to form siloxy-conjugated enes. On the other hand, the fast hydrolysis reaction leads to a siloxane network. Thus various condensation and dehydration reactions lead to a functionalized siloxane polymer with a lot of inherentπ -bonded carbon atoms. The gel obtained shows strong room-temperature photoluminescence (PL) with a maxima at 655 nm. The origin of PL is the presence of large amount of delocalized π-electrons in the system, which can enhance the radiative recombination of holes and electrons, which is further supported by the ESR spectra of the gel

Biosynthetic Potential of Bioactive Streptomycetes Isolated From Arid Region of the Thar Desert, Rajasthan (India)

Acquisition of Actinobacteria, especially Streptomyces from previously underexplored habitats and the exploration of their biosynthetic potential have gained much attention in the rejuvenated antibiotics search programs. Herein, we isolated some Streptomyces strains, from an arid region of the Great Indian Thar Desert, which possess an ability to produce novel bioactive compounds. Twenty-one morphologically distinctive strains differing in their aerial and substrate mycelium were isolated by employing a stamping method. Among them, 12 strains were identified by a two-level antimicrobial screening method, exerting antimicrobial effects against a panel of indicator strains including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus species. Based on their potent antimicrobial activity, four isolates were further explored by 16S rRNA gene-based identification, genetic screening, and metabolomic analysis; and it was found that these strains belong to the genus Streptomyces. The selected strains were found to have polyketide synthase and non-ribosomal peptide synthetase systems. In addition, extracellular metabolomic screening revealed that the isolates produced analogs of doxorubicinol, pyrromycin, erythromycin, and 6-13 other putative novel metabolites. These results demonstrate the significance of Streptomyces inhabiting the arid region of Thar Desert, suggesting that similar arid environments can be considered as the reservoirs of novel Streptomyces strains that could have biotechnological significance

Data_Sheet_1_Biosynthetic Potential of Bioactive Streptomycetes Isolated From Arid Region of the Thar Desert, Rajasthan (India).pdf

<p>Acquisition of Actinobacteria, especially Streptomyces from previously underexplored habitats and the exploration of their biosynthetic potential have gained much attention in the rejuvenated antibiotics search programs. Herein, we isolated some Streptomyces strains, from an arid region of the Great Indian Thar Desert, which possess an ability to produce novel bioactive compounds. Twenty-one morphologically distinctive strains differing in their aerial and substrate mycelium were isolated by employing a stamping method. Among them, 12 strains were identified by a two-level antimicrobial screening method, exerting antimicrobial effects against a panel of indicator strains including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus species. Based on their potent antimicrobial activity, four isolates were further explored by 16S rRNA gene-based identification, genetic screening, and metabolomic analysis; and it was found that these strains belong to the genus Streptomyces. The selected strains were found to have polyketide synthase and non-ribosomal peptide synthetase systems. In addition, extracellular metabolomic screening revealed that the isolates produced analogs of doxorubicinol, pyrromycin, erythromycin, and 6-13 other putative novel metabolites. These results demonstrate the significance of Streptomyces inhabiting the arid region of Thar Desert, suggesting that similar arid environments can be considered as the reservoirs of novel Streptomyces strains that could have biotechnological significance.</p