https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Actinobacteria are Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla, and they are ubiquitously distributed in both aquatic and terrestrial ecosystems. Many Actinobacteria have a mycelial lifestyle and undergo complex morphological differentiation. They also have an extensive secondary metabolism and produce about two-thirds of all naturally derived antibiotics in current clinical use, as well as many anticancer, anthelmintic, and antifungal compounds. Consequently, these bacteria are of major importance for biotechnology, medicine, and agriculture. Actinobacteria play diverse roles in their associations with various higher organisms, since their members have adopted different lifestyles, and the phylum includes pathogens (notably, species of Corynebacterium, Mycobacterium, Nocardia, Propionibacterium, and Tropheryma), soil inhabitants (e.g., Micromonospora and Streptomyces species), plant commensals (e.g., Frankia spp.), and gastrointestinal commensals (Bifidobacterium spp.). Actinobacteria also play an important role as symbionts and as pathogens in plant-associated microbial communities. This review presents an update on the biology of this important bacterial phylum.

/pdf/taxonomy-physiology-and-natural-products-of-actinobacteria-1arwsidgil.pdf

Taxonomy, Physiology, and Natural Products of Actinobacteria

Life and element cycling on Earth is directly related to electron transfer (or redox) reactions. An understanding of biogeochemical redox processes is crucial for predicting and protecting environmental health and can provide new opportunities for engineered remediation strategies. Energy can be released and stored by means of redox reactions via the oxidation of labile organic carbon or inorganic compounds (electron donors) by microorganisms coupled to the reduction of electron acceptors including humic substances, iron-bearing minerals, transition metals, metalloids, and actinides. Environmental redox processes play key roles in the formation and dissolution of mineral phases. Redox cycling of naturally occurring trace elements and their host minerals often controls the release or sequestration of inorganic contaminants. Redox processes control the chemical speciation, bioavailability, toxicity, and mobility of many major and trace elements including Fe, Mn, C, P, N, S, Cr, Cu, Co, As, Sb, Se, Hg, Tc, a...

http://pubs.acs.org/doi/pdf/10.1021/es9026248

Biogeochemical Redox Processes and their Impact on Contaminant Dynamics

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.

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Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis, and Antiviral Activities; Affecting the Immune and Nervous Systems, and other Miscellaneous Mechanisms of Action

Marine actinomycetes: an ongoing source of novel bioactive metabolites.

More than 100 million individuals worldwide are exposed to arsenic-contaminated water, making the investigation of arsenic mobility in aquatic systems of utmost importance. Iron (hydr)oxides play a key role in preventing arsenic release in aquifers and soils due to their strong arsenic sorption and are even used to remove arsenic in water treatment. Neutrophilic Fe(II)-oxidizing bacteria produce Fe(III) minerals and therefore have the potential to affect arsenic mobility. In the present study, we demonstrate that the metabolism of anaerobic nitratereducing and phototrophic Fe(II)-oxidizing bacteria is not significantly affected by arsenate concentrations of up to 500 µM (37.5 mg/L). Even in the presence of the more toxic arsenic species, arsenite, cell metabolism was significantly impaired only at the highest arsenite concentration (500 µM) for one of the Fe(II)-oxidizers. All Fe(II)-oxidizing bacteria tested effectively immobilized arsenic during Fe(II) oxidation (>96%), lowering the remaining dissolved arsenic concentrations to values close to or even lower than the current drinking water limit of 10 µg/L. Since the minerals formed by these bacteria includedhighlycrystallineFe(III)mineralsthatarehardlyreducible byFe(III)-reducingbacteria,stimulationofarsenicimmobilization by Fe(II)-oxidizing bacteria can potentially support water treatmentsystemsorevenbeappliedasaneffectiveremediation strategy.

Anaerobic Fe(II)-oxidizing bacteria show as resistance and immobilize as during Fe(III) mineral precipitation.

Caboxamycin, a new benzoxazole antibiotic, was detected by HPLC-diode array screening in extracts of the marine strain Streptomyces sp. NTK 937, which was isolated from deep-sea sediment collected in the Canary Basin. The structure of caboxamycin was determined by mass spectrometry, NMR experiments and X-ray analysis. It showed inhibitory activity against Gram-positive bacteria, selected human tumor cell lines and the enzyme phosphodiesterase.

/pdf/caboxamycin-a-new-antibiotic-of-the-benzoxazole-family-1dm472v0aa.pdf

Caboxamycin, a new antibiotic of the benzoxazole family produced by the deep-sea strain Streptomyces sp. NTK 937*

Molecular-level modes of As binding to Fe(III) (oxyhydr)oxides precipitated by the anaerobic nitrate-reducing Fe(II)-oxidizing Acidovorax sp. strain BoFeN1

Albidopyrone, a new α-pyrone-containing secondary metabolite, was produced by Streptomyces sp. NTK 227, a strain isolated from Atlantic Ocean sediment and found to be a member of the Streptomyces albidoflavus 16S rRNA gene clade. The structure of the compound was determined by MS and NMR spectroscopy, and found to have a moderate inhibitory activity against protein-tyrosin phosphatase B.

/pdf/albidopyrone-a-new-a-pyrone-containing-metabolite-from-2ogp0tyqkq.pdf

Claudia Hohmann

Papers

Anaerobic Fe(II)-oxidizing bacteria show as resistance and immobilize as during Fe(III) mineral precipitation.

Caboxamycin, a new antibiotic of the benzoxazole family produced by the deep-sea strain Streptomyces sp. NTK 937*

Molecular-level modes of As binding to Fe(III) (oxyhydr)oxides precipitated by the anaerobic nitrate-reducing Fe(II)-oxidizing Acidovorax sp. strain BoFeN1

Albidopyrone, a new α-pyrone-containing metabolite from marine-derived Streptomyces sp. NTK 227

Immobilization of arsenic in rice paddy soil by iron(II)-oxidizing bacteria