Development of Silica Gel-Supported Modified Macroporous Chitosan Membranes for Enzyme Immobilization and Their Characterization Analyses

The present work was aimed at developing stability enhanced silica gel-supported macroporous chitosan membrane for immobilization of enzymes. The membrane was surface modified using various cross-linking agents for covalent immobilization of enzyme Bovine serum albumin. The results of FT-IR, UV–vis, and SEM analyses revealed the effect of cross-linking agents and confirmed the formation of modified membranes. The presence of silica gel as a support could provide a large surface area, and therefore, the enzyme could be immobilized only on the surface, and thus minimized the diffusion limitation problem. The resultant enzyme immobilized membranes were also characterized based on their activity retention, immobilization efficiency, and stability aspects. The immobilization process increased the activity of immobilized enzyme even higher than that of total (actual) activity of native enzyme. Thus, the obtained macroporous chitosan membranes in this study could act as a versatile host for various guest molecules.     

Design, synthesis, and biological evaluation of a novel class of fluorescein-based N-glycosylamines

A series of fluorescein-based N-glycosylamines was synthesized from the corresponding fluorescein amine and a partially protected d-glucose. The physiochemical investigation of these compounds by spectral and morphological studies reveals their gelation potential. The exclusive localization of fluorescence in the cytoplasm through cell imaging studies reveals the anti-cancer potentials of N-glycosylamines.     

DNA Barcode Authentication of Wood Samples of Threatened and Commercial Timber Trees within the Tropical Dry Evergreen Forest of India

Background

India is rich with biodiversity, which includes a large number of endemic, rare and threatened plant species. Previous studies have used DNA barcoding to inventory species for applications in biodiversity monitoring, conservation impact assessment, monitoring of illegal trading, authentication of traded medicinal plants etc. This is the first tropical dry evergreen forest (TDEF) barcode study in the World and the first attempt to assemble a reference barcode library for the trees of India as part of a larger project initiated by this research group.

Methodology/Principal Findings

We sampled 429 trees representing 143 tropical dry evergreen forest (TDEF) species, which included 16 threatened species. DNA barcoding was completed using rbcL and matK markers. The tiered approach (1^st tier rbcL; 2^nd tier matK) correctly identified 136 out of 143 species (95%). This high level of species resolution was largely due to the fact that the tree species were taxonomically diverse in the TDEF. Ability to resolve taxonomically diverse tree species of TDEF was comparable among the best match method, the phylogenetic method, and the characteristic attribute organization system method.

Conclusions

We demonstrated the utility of the TDEF reference barcode library to authenticate wood samples from timber operations in the TDEF. This pilot research study will enable more comprehensive surveys of the illegal timber trade of threatened species in the TDEF. This TDEF reference barcode library also contains trees that have medicinal properties, which could be used to monitor unsustainable and indiscriminate collection of plants from the wild for their medicinal value.     

The effect of fucoidan from brown seaweed Sargassum wightii on WSSV resistance and immune activity in shrimp Penaeus monodon (Fab)

The polysaccharide-fucoidan was extracted from brown seaweed Sargassum wightii and characterized through FT-IR and ¹³C & ¹H NMR analysis. The extracted fucoidan was supplemented with pellet diets at three different concentrations (0.1, 0.2 and 0.3%). The fucoidan supplemented diets were fed to Penaeus monodon for 45 days, then challenged with WSSV and the mortality percentage was recorded daily up to 21 days. During the challenge test, the control group showed 100% mortality within 10 days, but in the experimental groups, the mortality percentage (51-72% within 21 days) was decreased considerably (P < 0.05) with respect to the concentrations of fucoidan. The reduction in mortality percentage of experimental groups over control group was ranged from 50.81 to 68.06%. During challenge experiment, the immunological parameters such as THC, prophenoloxidase activity, respiratory burst activity, superoxide dismutase activity and phagocytic activity were measured before injection of WSSV (0 day) and after the injection of WSSV on 10th and 21st days, respectively. All the immunological parameters of experimental groups were significantly (P < 0.05) increased than control group. RT-PCR analysis confirmed the considerable reduction of WSSV DNA copy numbers with respect to the concentration of fucoidan. It was concluded that P. monodon fed with fucoidan of S. wightii supplemented diet had enhanced the innate immunity and increased resistance against WSSV infection.     

Synthesis and antioxidant activity of a novel class of 4,6-O-protected O-glycosides and their utility in disaccharide synthesis

BF₃·Et₂O-catalysed O-glycosylation of 1,2,3-tri-O-acetyl-4,6-O-butylidene- and ethylidene-β-d-glucopyranose with different aliphatic and aromatic alcohols proceeds for the most part with complete retention of anomeric configuration. Antioxidant activity of O-glycosides shows significant inhibition (IC₅₀ ∼77%). 1,3-Dipolar cycloaddition of terminal alkyne derivatives of O-glycosides with glycosyl azide results in disaccharides.     

Synthesis of quinoline-based glycoconjugates: a facile one-pot three-component reaction

A multicomponent one-pot reaction involving propargyl glycosides, methoxy-substituted aromatic aldehydes and aromatic amines using Cu(I) as catalyst is described, which provides an efficient and practical route to synthesize several quinoline-based glycoconjugates in good yield.     

A facile synthesis of sugar-pyrazole derivatives

A facile synthesis of sugar-pyrazole derivatives has been accomplished by condensation of sugar-chalcone with hydrazine hydrate under neutral conditions resulting in yields of 70–85%. The products are characterized by FTIR and NMR spectroscopy and by elemental analysis. The β-anomeric forms for these derivatives were assigned by NMR spectroscopy.     

Studies on the synthesis of ether-, substituted alkyl-, or aryl-linked C-disaccharide derivatives

A series of ether-, substituted alkyl-, or aryl-linked disaccharide derivatives have been synthesized in relatively good yield and characterized using different spectral techniques including single-crystal X-ray diffraction (XRD). β-Anomeric forms of sugar moiety in these derivatives were identified from ¹H NMR studies. The existence of inter- and intramolecular hydrogen bonding interactions were identified from single-crystal XRD studies.     

FACE-selective fluorogenic cycloaddition reaction between coumarin azides and sugar terminal alkynes: an experimental and computational study

Copper catalyzed azide–alkyne cycloaddition reaction (CuAAC) of non-fluorescent coumarin azides and sugar terminal alkynes afforded intense fluorescent 1,2,3-triazoles in 75–85% of yield. The photophysical properties of coumarin–sugar triazoles influenced greatly, upon introducing different substituents at 6th and 7th positions. The experimental observations were further supported by TD-DFT computational studies.