https://cyberleninka.org/article/n/132565.pdf

Discovery and resupply of pharmacologically active plant-derived natural products: A review.

Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times ( 2 S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments.

Recent Advances in Petroleum Microbiology

An anaerobic methanotroph (ANME-2d) can perform nitrate-driven anaerobic oxidation of methane through reverse methanogenesis, using nitrate as the terminal electron acceptor, and nitrite produced by ANME-2d is reduced to dinitrogen gas through a syntrophic relationship with an anaerobic ammonium-oxidizing bacterium. Microbes capable of the anaerobic oxidation of methane (AOM) are important for controlling the flux of methane from anoxic marine sediments. Recent work has demonstrated AOM coupled to sulphate reduction in a consortium of ANME (anaerobic methanotrophic archaea) and sulphate-reducing bacteria, and coupled to nitrite reduction in consortia enriched with the bacterium Candidatus Methylomirabilis oxyfera and the novel ANME-2d lineage. Here Gene Tyson and colleagues show that a novel ANME-2d archaeon, which they name Candidatus Methanoperedens nitroreducens, is able to performing nitrate-driven AOM without a partner organism via reverse methanogenesis with nitrate as the terminal electron acceptor, using genes for nitrate reduction that have been laterally transferred from a bacterial donor. The authors speculate that ANME- 2d or Methanoperedenaceae lineage may have a pivotal role in linking the global carbon and nitrogen cycles in anoxic environments. Anaerobic oxidation of methane (AOM) is critical for controlling the flux of methane from anoxic environments. AOM coupled to iron1, manganese1 and sulphate2 reduction have been demonstrated in consortia containing anaerobic methanotrophic (ANME) archaea. More recently it has been shown that the bacterium Candidatus ‘Methylomirabilis oxyfera’ can couple AOM to nitrite reduction through an intra-aerobic methane oxidation pathway3. Bioreactors capable of AOM coupled to denitrification have resulted in the enrichment of ‘M. oxyfera’ and a novel ANME lineage, ANME-2d4,5. However, as ‘M. oxyfera’ can independently couple AOM to denitrification, the role of ANME-2d in the process is unresolved. Here, a bioreactor fed with nitrate, ammonium and methane was dominated by a single ANME-2d population performing nitrate-driven AOM. Metagenomic, single-cell genomic and metatranscriptomic analyses combined with bioreactor performance and 13C- and 15N-labelling experiments show that ANME-2d is capable of independent AOM through reverse methanogenesis using nitrate as the terminal electron acceptor. Comparative analyses reveal that the genes for nitrate reduction were transferred laterally from a bacterial donor, suggesting selection for this novel process within ANME-2d. Nitrite produced by ANME-2d is reduced to dinitrogen gas through a syntrophic relationship with an anaerobic ammonium-oxidizing bacterium, effectively outcompeting ‘M. oxyfera’ in the system. We propose the name Candidatus ‘Methanoperedens nitroreducens’ for the ANME-2d population and the family Candidatus ‘Methanoperedenaceae’ for the ANME-2d lineage. We predict that ‘M. nitroreducens’ and other members of the ‘Methanoperedenaceae’ have an important role in linking the global carbon and nitrogen cycles in anoxic environments.

Anaerobic oxidation of methane coupled to nitrate reduction in a novel archaeal lineage

This Review summarizes the development of catalytic asymmetric dearomatization (CADA) reactions. The CADA reactions discussed herein include oxidative dearomatization reactions, dearomatization by DielsAlder and related reactions, the alkylative dearomatization of electron-rich arenes, transition-metal-catalyzed dearomatization reactions, cascade sequences involving asymmetric dearomatization as the key step, and nucleophilic dearomatization reactions of pyridinium derivatives. Asymmetric dearomatization reactions with chiral auxiliaries and catalytic asymmetric reactions of dearomatized substrates are also briefly introduced. This Review intends to provide a concept for catalytic asymmetric dearomatization.

Catalytic Asymmetric Dearomatization Reactions

Evolution in the field of the total synthesis of natural products has led to exciting developments over the last decade. Numerous chemoselective and enantioselective methodologies have emerged from total syntheses, resulting in efficient access to many important natural product targets. This Review highlights recent developments concerning dearomatization, a powerful strategy for the total synthesis of architecturally complex natural products wherein planar, aromatic scaffolds are converted to three-dimensional molecular architectures.

Dearomatization Strategies in the Synthesis of Complex Natural Products

This tutorial review provides a survey of syntheses in which an enzymatic step contributed to generating downstream molecular complexity in the target. The first part provides a guide to the types of enzymatic transformations suitable for incorporation into synthetic schemes. The principles of symmetry, especially the concept of “latent symmetry”, which are often used to simplify enantiodivergent design of targets, are discussed next. The examples are discussed in the order of a degree of experimental difficulty associated with the execution of a particular biological technique. Lipase resolutions and desymmetrizations are discussed first followed by more advanced protocols involving oxidoreductase enzymes and ending with examples of syntheses that employ pathway engineering and directed evolution of proteins. Future prospects of biocatalytic methods as means of efficient preparation of target compounds are indicated. The authors hope that the review will serve to convince those synthetic chemists reluctant to use biological methods to include enzymatic procedures in their design.

Applications of biotransformations and biocatalysis to complexity generation in organic synthesis.

This account is a tribute to Professor David Gibson in recognitionof his discovery of enzymatic dihydroxylation of aromatic compoundsfour decades ago. Here are highlighted some of the milestones inmicrobiology, biochemistry, molecular biology, and synthetic organicchemistry connected with this unique reaction. Gibson’sdiscovery greatly contributed to advancing biocatalysis as a disciplinewith major impact on synthesis of optically pure compounds. Personalrecollections of several chemists who have embraced this technologyin their own work, along with the authors’ recollectionsof the early days of research involving the CIS-dihydrodiols,are provided as Notes at the end of the article. 1 Introduction: History of Biocatalysis 2 The Discovery of Enzymatic Dihydroxylation 3 Processing of Arenes by Oxidoreductase Enzymes 4 Considerations of the Mechanism 5 Diversity of Metabolites 6 CIS-Dihydrodiols as SyntheticIntermediates: Analysis of Reactivity and Symmetry Options 7 Historically Important Milestones in Applications to Synthesis 8 Outlook 9 Notes

Celebrating 20 Years of SYNLETT - Special Account Onthe Merits of Biocatalysis and the Impact of Arene cis-Dihydrodiolson Enantioselective Synthesis

From Discovery to Application: 50 Years of the Vinylcyclopropane–Cyclopentene Rearrangement and Its Impact on the Synthesis of Natural Products

ConspectusWe became interested in approaches to morphine in the early 1990s following our immersion into the new program on the enzymatic dihydroxylation of aromatics. Larry Kwart, a former classmate of one of us at Rice University, who worked with our group at Virginia Tech in the mid-1980s, introduced to us the use of blocked mutants of Pseudomonas putida (Pp39D) for the production of arene-cis-dihydrodiols. Larry had gained expertise in microbiology from a postdoctoral stay with David Gibson, who discovered this unique enzymatic transformation, and he helped us to establish a strong program in chemoenzymatic synthesis that continues to this day. Without his pioneering effort, none of our accomplishments in chemoenzymatic synthesis, including the various approaches to morphine, would have materialized.Here we trace the evolution of our approaches to morphine alkaloids and some commercial opiate-derived medicinal agents. The design features and chronology of our approaches are discussed in a way that all...

Josephine W. Reed

Papers

Applications of biotransformations and biocatalysis to complexity generation in organic synthesis.

Celebrating 20 Years of SYNLETT - Special Account Onthe Merits of Biocatalysis and the Impact of Arene cis-Dihydrodiolson Enantioselective Synthesis

From Discovery to Application: 50 Years of the Vinylcyclopropane–Cyclopentene Rearrangement and Its Impact on the Synthesis of Natural Products

The quest for a practical synthesis of morphine alkaloids and their derivatives by chemoenzymatic methods.

Von der Entdeckung bis zur Anwendung: 50 Jahre Vinylcyclopropan‐Cyclopenten‐Umlagerung und ihre Bedeutung in der Naturstoffsynthese