Bioconversion of Chitin to Bioactive Chitooligosaccharides: Amelioration and Coastal Pollution Reduction by Microbial Resources

Chitin-metabolizing products are of high industrial relevance in current scenario due to their wide biological applications, relatively lower cost, greater abundance, and sustainable supply. Chitooligosaccharides have remarkably wide spectrum of applications in therapeutics such as antitumor agents, immunomodulators, drug delivery, gene therapy, wound dressings, as chitinase inhibitors to prevent malaria. Hypocholesterolemic and antimicrobial activities of chitooligosaccharides make them a molecule of choice for food industry, and their functional profile depends on the physicochemical characteristics. Recently, chitin-based nanomaterials are also gaining tremendous importance in biomedical and agricultural applications. Crystallinity and insolubility of chitin imposes a major hurdle in the way of polymer utilization. Chemical production processes are known to produce chitooligosaccharides with variable degree of polymerization and properties along with ecological concerns. Biological production routes mainly involve chitinases, chitosanases, and chitin-binding proteins. Development of bio-catalytic production routes for chitin will not only enhance the production of commercially viable chitooligosaccharides with defined molecular properties but will also provide a means to combat marine pollution with value addition.     

Controlling morphology of peptide‐based soft structures by covalent modifications

Control of gross morphology of soft matter remains an area of continued interest. Towards this goal, this paper describes conjugation of mannose residues and introduction of thiol functionalities to diphenylalanine (FF) dipeptide, a fibrillating motif from amyloid‐β peptide, as covalent modifiers of its solution‐phase self‐assembly process. It was found that covalent attachment of a single mannose residue to FF leads to the retention of tubular structures, whereas the conjugation of two mannose units, linked through a Lys residue, resulted in a dramatic change from tubular morphology to spherical structures. However, a similar switch to spherical objects could be achieved by introducing a thiol residue in the mono‐mannosylated FF dipeptide. Interestingly, these glycopeptides also exhibited interaction with concanavalin A, thereby providing an indirect evidence for the availability of mannose units for the process of lectin‐carbohydrate interaction in the self‐organized state. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Can lantana seeds be utilized in lamb rations?

Lantana seeds contain 70.6 g crude protein, 12.8 g ether extract, 103.1 g crude fibre, 761.0 g nitrogen-free extract, 52.5 g total ash, 8.4 g calcium and 2.5 g phosphorus/kg dry matter. The replacement, by lantana seeds, of 200 g maize/kg of concentrate mixture for lambs was studied in two experiments lasting 3–4 months. The crude protein concentration in the lantana ration was lower than in the maize, and significantly (P<0.01) so in the second experiment. In the first experiment, the digestibility and intakes of dietary crude protein (DCP) and total dietary nitrogen (TDN) of the lantana group were not significantly lower. In the second experiment, dry matter and crude protein digestibility and intakes of DCP and TDN of the lantana group were significantly (P<0.01) lower than the maize group. Even after adjustment for mean protein concentration in the diets, the intakes of DCP (P<0.01) and TDN (P<0.05) in the lantana group were significantly lower. In a repeat metabolic trial also, the adjusted intakes of both DCP and TDN (P<0.01) of the lantana group were significantly lower. In spite of the depression in feed utilization, the biochemical and haematological parameters of the blood of animals in the lantana group were within the normal range. The apparent non-toxicity of lantana seeds to lambs over long-term feeding trials calls for further work on their possible utilization as a feed ingredient.     

Amplification of fluorescently labelled DNA within gram-positive and acid-fast bacteria.

Representative organisms from a variety of Gram-positive genera were subjected to varying regimes in order to optimise the intracellular amplification of DNA. The bacteria were subjected to treatments with paraformaldehyde, muramidases and mild acid hydrolysis to discover which regime made each organism permeable to the amplification reagents yet allowed retention of the fluorescein-labelled amplified products within the cell. Scanning electron micrographs were used to corroborate the effectiveness of the treatments, as seen by fluorescent photomicrographs, with the damage caused to the bacterial walls. A combination of mutanolysin and lysozyme was found most effective for Bacillus cereus, whereas permeabilisation of Streptomyces coelicolor, Lactococcus lactis and Clostridium sporogenes was most effective when exposed to lysozyme only. Surprisingly, direct amplification with no pre-treatment gave the brightest fluorescence in Mycobacterium phlei. Comparing the techniques of whole cell PCR, primed in situ labelling (PRINS), and cycle PRINS showed that under the conditions used the strongest intensity of fluorescence was obtained with in situ PCR; only L. lactis and M. phlei produced signals with cycle PRINS, fluorescence was not seen for any of the organisms with PRINS.