Bacteria alkaloid production

Nonvolatile Nitrosamines In Tobacco. A method which we developed several years ago for the analysis of tobacco-specific nitrosamines (TSNA 31) involves extraction of tobacco with buffered ascorbic acid TpH 4.5) followed by partition with ethyl acetate, chromatographic clean-up on silica gel, and analysis by HPLC-TEA (Figure 9). Results obtained with this method for a large spectrum of tobacco products (Table IV), strongly support the concept that the levels of nitrate and alkaloids, and especially the methods for curing and fermentation, determine the yields of TSNA in tobacco products. Recent and as yet preliminary data from snuff analyses indicate that aerobic bacteria play a role in the formation of TSNA during air curing and fermentation. 

Bacteria and fungi play an essential role in the biosphere by breaking down the many aromatic products of plant metabolism.150 153 These include vast amounts of lignin, alkaloids, flavonoid compounds, and other biochemically "inert" substances. Lignin is a major constituent of wood and a plant product second only to cellulose in abundance. 

Bacteria, protozoa, and venomous animals synthesize numerous toxins that are used to kill their prey or to defend themselves. Sea anemones, jellyfish, cone snails, insects, spiders, scorpions, and snakes all make potent and highly specific neurotoxins. Plants form a host of alkaloids and other specialized products, some of which are specifically neurotoxic and able to deter predators. More than 500 species of marine cone snails of the genus Conus synthesize a vast array of polypeptide toxins (conotoxins), 487-489 some with unusual posttranslational modifications.490 491 The slow-moving snails are voracious predators that use their toxins, which they inject with a disposible harpoonlike tooth,492 to paralyze fish, molluscs, or worms.493... 

The biosynthetic studies undertaken to date on microbial marine natural products well illustrate the diversity of metabolic pathways encountered in cultured marine bacteria. Examples include brominated alkaloids such as pentabromopseudiline (Structure 2.1),19 polyketide or mixed polyketide metabolites such as oncorhyncholide (Structure 2.2),20 aplasmomycin (Structure 2.3),21 and andrimid (Structure 2.4),22 or the cyclic depsipeptide salinamide A (Structure 2.5).23 As researchers continue to define more specific culture media and a wider range of marine bacteria from diverse habitats are successfully placed into culture, the true biosynthetic potential of these prolific and adaptable microorganisms can be explored. 

A natural (1 counterpart has not yet been obtained for every proteinogenic a-amino acid (Table 1.5.1). /I-A la 1 and (R)- or (S)-fi- Aib 2 seem to be present in all kingdoms, with no obvious preferences. Selected /l-amino acids, for example /1-Lys 4, have been found only within one kingdom (i.e. bacteria), although they might be quite common there. Accordingly, the various natural products that contain /1-Lys substructures have been isolated exclusively from bacteria. On the other hand, alkaloids and peptides linked to / -Phe 8 have been obtained from bacteria, plants, and fungi, whereas the free /l-amino acid / -Phe 8 has not yet been isolated from natural sources. 

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