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Comprehensive Summary: N,N,N‐Trimethyl‐D‐glucosamine (TMG)‐chitotriomycin, a naturally occurring chitin related oligosaccharide, is a specific β‐N‐acetylhexosaminidases (HexNAcases) inhibitor for insects and fungi. Although TMG‐chitoriomycin holds great promise as a novel class insecticide and fungicide, the limited accessibility of TMG‐chitotriomycin prevents its further biological evaluation. We report herein a simple and eco‐friendly chemoenzymatic approach for the efficient synthesis of TMG‐chitotriomycin and its analogues. In this strategy, the readily available chitosan was enzymatically hydrolyzed and chemically N‐acetylated to afford the chitooligosaccharides ranging from disaccharide to hexasaccharide. These chitooligosaccharides were selectively deacetylated by two different chitin deacetylases followed by chemical N‐trimethylation to obtain the desired TMG‐chitotriomycin and a total of 13 TMG‐chitotriomycin analogues in the longest linear sequence of 4 steps in over 12% total yields. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify the potential level of protection that secondary disinfection may provide in response to an intrusion event. Although several uncertainties exist regarding intrusion events, this study presents an analysis of the inactivation provided by disinfectant residuals by using a distribution system model, inactivation and disinfectant decay models, and conservative assumptions based on available data. A variety of conditions were modeled, including a range of water quality parameters (pH, temperature); inactivation of two microorganisms, Giardia and E. coli O157:H7; and intrusion water dilution ratios. Despite the assumptions inherent in the model, several generalizations were derived from the study. A free chlorine residual of 0.5 mg/L may be insufficient to provide adequate control of disinfectant-resistant Giardia even at low pH (6.5) and high temperature (25 [degrees]C) conditions that enhance chlorine effectiveness. For E. coli, an organism of 'average' disinfectant resistance relative to others, a residual of 0.5 mg/L may provide ample protection against intrusion even assuming that the chlorine residual is reduced within several minutes, such as would be predicted to occur with sewage intrusion at levels below 1% of the total flow. Importantly, chloramines may have a negligible benefit in terms of protecting against intrusion for even relatively susceptible organisms such as E. coli. Consequently, systems should consider protection against intrusion when choosing their secondary disinfectant. DOI: 10.1061/(ASCE)0733-9372(2008)134:4(231) CE Database subject headings: Potable water; Water distribution system; Disinfection; Chlorine.

Tryptamine derivatives such as tryptamine and bacillamides were strong algicidal compounds promising in controlling harmful algae blooms, but their bioactivity and application researches were hindered by extremely low natural production rates. This study found an induced production of algicidal tryptamine derivatives by co-culture of marineStreptomyceswithBacillus mycoides, and optimised the culture method through changing important factors such as medium nutrition content, culture mode and pH value. The final established co-culture method used only 5 g yeast extracts and 5 g glycerol in 1 L 75% sea water, but got a yield of 14.9 mg/LN-acetyltryptamine, 2.8 mg/LN-propanoyltryptamine, 3.0 mg/L bacillamide A, 13.7 mg/L bacillamide B and 9.6 mg/L bacillamide C, which were all undetectable under normal culture conditions. [ABSTRACT FROM PUBLISHER]