Structure, Biosynthesis, and Occurrence of Bacterial Pyrrolizidine Alkaloids

Chemical reactions that are named in honor of their true or at least perceived discoverers are known as “name reactions”. This review is a collection of biological representatives of named chemical reactions. Emphasis is placed on reaction types and catalytic mechanisms that showcase both the chemical diversity in natural product biosynthesis as well as the parallels with synthetic organic chemistry. An attempt has been made to describe the enzymatic mechanisms of catalysis within the context of their synthetic counterparts whenever possible and to discuss the mechanistic hypotheses for those reactions that are presently active areas of investigation. This review has been categorized by reaction type, e.g., condensation, nucleophilic addition, reduction and oxidation, substitution, carboxylation, radical-mediated, and rearrangements, which are subdivided by named reactions.

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“…Similar biosynthetic route has also been proposed for the formation of pyrrolizixenamides in Xenorhabdus stockiae . [167] …”

Section: Oxidation and Reduction Reactionsmentioning

confidence: 99%

The Enzymology of Organic Transformations: A Survey of Name Reactions in Biological Systems

2017

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“…The 1 H, 13 CNMR, and HRMS spectra of synthetic pyreudione A( 1)m atched those of isolated 1,a sd id their HPLC retention times.I mportantly,t he specific optical rotation values were in good agreement (see the Supporting Information). Synthetic enantiomer (R)-1 displayed aspecific optical rotation with same magnitude yet opposite sign.…”

mentioning

confidence: 90%

“…Their bicyclicp yrrolizidine alkaloid (PA) core structure is ac ommonly found structural motif in plant alkaloids,y et rarely found in bacterial metabolites. [13,14] Bacterial PA ss uch as jenamidines, [15] and structures similar to PA ssuch as brabantamides, [16] have been reported to show antitumor or antibacterial activity.The pyreudiones additionally belong to the class of tetramic acids,w hich also often display potent biological activities. [17,18] Members of this structural class occur predominantly in the Z-exo-enol form, with the hydroxy group hydrogen bonded to the lactam carbonyl group.…”

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confidence: 99%

Bacterial Alkaloids Prevent Amoebal Predation

et al. 2016

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Bacterial defense mechanisms have evolved to protect bacteria against predation by nematodes, predatory bacteria, or amoebae. We identified novel bacterial alkaloids (pyreudiones A-D) that protect the producer, Pseudomonas fluorescens HKI0770, against amoebal predation. Isolation, structure elucidation, total synthesis, and a proposed biosynthetic pathway for these structures are presented. The generation of P. fluorescens gene-deletion mutants unable to produce pyreudiones rendered the bacterium edible to a variety of soil-dwelling amoebae.

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“…They are most likely produced as a chemical defense mechanism against herbivores. Some pyrrolizidine alkaloids, such as clazamycins and jenamidines, are biosynthesized by Gram-positive and Gram-negative bacteria [ 263 ]. Senecio species biosynthesize pyrrolizidine alkaloids in unique patterns, as senecionine N-oxide, as a common intermediate in the roots.…”

Section: Plant Toxinsmentioning

confidence: 99%

Comparison of Strategies to Overcome Drug Resistance: Learning from Various Kingdoms

Ogawara

2018

Molecules

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Drug resistance, especially antibiotic resistance, is a growing threat to human health. To overcome this problem, it is significant to know precisely the mechanisms of drug resistance and/or self-resistance in various kingdoms, from bacteria through plants to animals, once more. This review compares the molecular mechanisms of the resistance against phycotoxins, toxins from marine and terrestrial animals, plants and fungi, and antibiotics. The results reveal that each kingdom possesses the characteristic features. The main mechanisms in each kingdom are transporters/efflux pumps in phycotoxins, mutation and modification of targets and sequestration in marine and terrestrial animal toxins, ABC transporters and sequestration in plant toxins, transporters in fungal toxins, and various or mixed mechanisms in antibiotics. Antibiotic producers in particular make tremendous efforts for avoiding suicide, and are more flexible and adaptable to the changes of environments. With these features in mind, potential alternative strategies to overcome these resistance problems are discussed. This paper will provide clues for solving the issues of drug resistance.

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Structure, Biosynthesis, and Occurrence of Bacterial Pyrrolizidine Alkaloids

Cited by 36 publications

References 30 publications

The Enzymology of Organic Transformations: A Survey of Name Reactions in Biological Systems

The Enzymology of Organic Transformations: A Survey of Name Reactions in Biological Systems

Bacterial Alkaloids Prevent Amoebal Predation

Comparison of Strategies to Overcome Drug Resistance: Learning from Various Kingdoms

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