The design and synthesis of a multifunctional macromolecular architecture featuring alternating cholic acid (CA) and glucose pendants in a polymer side-chain is reported. The target architecture was prepared by reversible addition–fragmentation chain-transfer copolymerization of styrene-conjugated CA (the bitter monomer) and acetyl-protected glucose appended maleimide (the sweet monomer) using the polyethylene glycol-conjugated chain transfer agent. Removal of the acetates resulted in amphiphilic “bitter-sweet” alternating copolymers that were self-assembled in aqueous media having CA containing bitter core and sugar-coated sweet shell. Dynamic light scattering measurements in water, field emission scanning electron microscopy, and transmission electron microscopy confirmed the formation of 40 to 75 nm sized micellar nanoscaffolds, depending on the chain-length of the copolymers. The nanoparticles successfully encapsulated hydrophobic molecules as witnessed via fluorescence spectroscopy using Nile red as an exemplary guest. Interestingly, the alternating copolymer recognized β-cyclodextrin (β-CD) through the formation of inclusion complexes with lateral cholate moieties in the polymer as evident from 2D NMR and nuclear Overhauser effect experiments. It is worth noting that the polymer and its inclusion complex were found to be capable of recognizing Concanavalin A (Con A), as shown by turbidimetric assay and isothermal titration calorimetry. Interestingly, the inclusion complex of the alternating copolymer showed significantly higher autofluorescence in the presence of Con A with respect to that of un-complexed one. Thus, the present study offers a simple way to prepare a multifunctional alternating copolymer having hydrophobic molecule encapsulation, inherent fluorescence, inclusion complex formation with β-CD, and lectin recognition capabilities.

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We report here a preliminary study on the interaction between two common enteric bacteria with the carp Cirrhinus mrigala, a major product of the sewage-fed fish-culture ponds of east Calcutta. The threshold concentration of bacteria in water above which they start appearing in fish muscle was determined. Beyond the threshold value, the concentration of bacteria in muscle varied linearly with the bacterial concentration in the water. A relationship was observed between the concentrations of bacteria in muscle and in the digestive tract with contents.

The total chemical synthesis of the pentasaccharide repeating unit of the O-polysaccharide from E. coli O132 is accomplished in the form of its 2-aminoethyl glycoside. The 2-aminoethyl glycoside is particularly important as it allows further glycoconjugate formation utilizing the terminal amine without affecting the stereochemistry of the reducing end. The target was achieved through a [3 + 2] strategy where the required monosaccharide building blocks are prepared from commercially available sugars through rational protecting group manipulation. The NIS-mediated activation of thioglycosides was used extensively for the glycosylation reactions throughout.

Total synthesis of the pentasaccharide repeating unit of the OPS from Halomonas ventosae RU5S2EL is accomplished through a [3+2] block strategy. Picoloyl-induced hydrogen-bond-assisted aglycon delivery (HAD) is used for two consecutive 1,2-cis-L-rhamnosylations, and remote participation is used for α-selective glucosylation. The choice of 2aminoethyl glycoside at the reducing end is opted for, leaving the scope for further glycoconjugate formation without hampering the reducing-end stereochemistry.