Synthesis and Application of Photocaged Isopropyl β-D-1-Thiogalactopyranoside for Light-Mediated Control of Bacterial Gene Expression.

Photocaged compounds are chemical conjugates that are designed to release an active molecule upon exposure to light of a specific wavelength. In recent years, photocaged inducer molecules such as caged isopropyl β-D-1-thiogalactopyranoside (cIPTG) have been increasingly used as a powerful tool for light-driven gene expression in bacteria, allowing researchers to precisely and noninvasively tune the expression of specific target genes. In this chapter, we present a guideline for the synthesis of 6-nitropiperonyl photocaged IPTG (NP-cIPTG) as well as its in vivo application as an optochemical on-switch of gene transcription in Escherichia coli and other bacteria.

Selective production of the itaconic acid-derived compounds 2-hydroxyparaconic and itatartaric acid.

There is a strong interest in itaconic acid in the medical and pharmaceutical sectors, both as an anti-bacterial compound and as an immunoregulator in mammalian macrophages. Fungal hosts also produce itaconic acid, and in addition they can produce two derivatives 2-hydroxyparaconic and itatartaric acid. Not much is known about these two derivatives, while their structural analogy to itaconate could open up several applications.

Utilization of a Branched Late-Stage Clickable Biotinylated Chassis on the Example of a Pittsburgh B Analogue.

Biotinylation is probably the most frequent and practically useful modification of molecules to facilitate selective and highly affine binding to (strept)avidin for immobilization, enrichment, and purification for further (bio)chemical or (bio)physical investigations. We present a protecting-group-free synthesis of a branched biotin bis-azide that enables dual-payload late-stage functionalization with arbitrary alkynes via click chemistry. Utility of the chassis is briefly showcased on the example of a valuable Pittsburgh B analogue, which binds pathological protein aggregates, commonly found in neurodegenerative diseases.

Are Users Good Assessors of Social Dominance in Domestic Horses?

Horse users and caretakers must be aware of the risks of mixing social groups. The current study investigated whether eight equine practitioners can assess the social dominance rank of 20 horses. The horses' feeding time and agonistic/aggressive and submissive behaviours were observed during the feed confrontation test, and the dominance index (DI) was calculated.

Application of Cyclic Diaryliodonium Salts in the Synthesis of Axially Chiral Natural Product Analogues.

The application of cyclic diaryliodonium salts in the synthesis of bioactive natural product analogues was demonstrated. Axially chiral biaryls were obtained via the enantioselective ring opening of cyclic diaryliodonium salts. Regioselective borylation was key in accessing both enantiomers of a biphenol key intermediate in eight steps overall.

From the Total Synthesis of Semi-Viriditoxin, Semi-Viriditoxic Acid and Dimeric Naphthopyranones to their Biological Activities in Burkitt B Cell Lymphoma.

Dimeric naphthopyranones are known to be biologically active, however, for the corresponding monomeric naphthopyranones this information is still elusive. Here the first enantioselective total synthesis of semi-viriditoxic acid as well as the synthesis of semi-viriditoxin and derivatives is reported. The key intermediate in the synthesis of naphthopyranones is an α,β-unsaturated δ-lactone, which we synthesized in two different ways (Ghosez-cyclization and Grubbs ring-closing metathesis), while the domino-Michael-Dieckmann reaction of the α,β-unsaturated δ-lactone with an orsellinic acid derivative is the key reaction.

Application of the C3-Methyltransferase StspM1 for the Synthesis of the Natural Pyrroloindole Motif.

Even though pyrroloindoles are widely present in natural products with different kinds of biological activities, their selective synthesis remains challenging with existing tools in organic chemistry, and there is furthermore a demand for stereoselective and mild methods to access this structural motif. Nature uses C3-methyltransferases to form the pyrroloindole framework, starting from the amino acid tryptophan. In the present study, the SAM-dependent methyltransferase StspM1 from sp.

Modular Approach for the Synthesis and Bioactivity Profiling of 8,8'-Biflavones.

In this work, we report the scalable and modular synthesis of a library of 55 monomeric and dimeric flavonoids including 14 8,8'-biflavones. The sterically demanding tetra--substituted axis of an acetophenone dimer key intermediate was constructed in a regioselective manner using Fe-mediated oxidative coupling. This step was systematically optimized and performed on up to multigram scale.

The Golgi stacking protein GRASP55 is targeted by the natural compound prodigiosin.

Background: The bacterial secondary metabolite prodigiosin has been shown to exert anticancer, antimalarial, antibacterial and immunomodulatory properties. With regard to cancer, it has been reported to affect cancer cells but not non-malignant cells, rendering prodigiosin a promising lead compound for anticancer drug discovery. However, a direct protein target has not yet been experimentally identified.

Generation of Cannabigerolic Acid Derivatives and Their Precursors by Using the Promiscuity of the Aromatic Prenyltransferase NphB.

NphB is an aromatic prenyltransferase with high promiscuity for phenolics including flavonoids, isoflavonoids, and plant polyketides. It has been demonstrated that cannabigerolic acid is successfully formed by the reaction catalysed by NphB using geranyl diphosphate and olivetolic acid as substrates. In this study, the substrate specificity of NphB was further determined by using olivetolic acid derivatives as potential substrates for the formation of new synthetic cannabinoids.

Production of tailored hydroxylated prodiginine showing combinatorial activity with rhamnolipids against plant-parasitic nematodes.

Bacterial secondary metabolites exhibit diverse remarkable bioactivities and are thus the subject of study for different applications. Recently, the individual effectiveness of tripyrrolic prodiginines and rhamnolipids against the plant-parasitic nematode , which causes tremendous losses in crop plants, was described. Notably, rhamnolipid production in engineered strains has already reached industrial implementation.

A Common C -Symmetric 2,2'-Biphenol Building Block and its Application in the Synthesis of (+)-di-epi-Gonytolide A.

A variety of biaryl polyketides exhibit remarkable bioactivities. However, their synthetic accessibility is often challenging. Herein, the enantioselective preparation and synthetic application of an axially chiral 2,2'-biphenol building block is outlined that represents a common motif of these intriguing natural products.

Generation of Aurachin Derivatives by Whole-Cell Biotransformation and Evaluation of Their Antiprotozoal Properties.

The natural product aurachin D is a farnesylated quinolone alkaloid, which is known to possess activity against the causative agent of malaria, spp. In this study, we show that aurachin D inhibits other parasitic protozoa as well. While aurachin D had only a modest effect on , two other trypanosomatids, and , were killed at low micromolar and nanomolar concentrations, respectively, in an in vitro assay.

Light-mediated control of gene expression in the anoxygenic phototrophic bacterium using photocaged inducers.

Photocaged inducer molecules, especially photocaged isopropyl-β-d-1-thiogalactopyranoside (cIPTG), are well-established optochemical tools for light-regulated gene expression and have been intensively applied in and other bacteria including or . In this study, we aimed to implement a light-mediated on-switch for target gene expression in the facultative anoxygenic phototroph by using different cIPTG variants under both phototrophic and non-phototrophic cultivation conditions. We could demonstrate that especially 6-nitropiperonyl-(NP)-cIPTG can be applied for light-mediated induction of target gene expression in this facultative phototrophic bacterium.

Simple Enzyme Immobilization for Flow Chemistry? An Assessment of Available Strategies for an Acetaldehyde-Dependent Aldolase.

Enzyme immobilization is a technology that enables (bio-)catalysts to be applied in continuous-flow systems. However, there is a plethora of immobilization methods available with individual advantages and disadvantages. Here, we assessed the influence of simple and readily available methods with respect to the performance of 2-deoxy-d-ribose-5-phosphate aldolase (DERA) in continuous-flow conditions.

Recent Advances in Biocatalysis for Drug Synthesis.

Biocatalysis is constantly providing novel options for the synthesis of active pharmaceutical ingredients (APIs). In addition to drug development and manufacturing, biocatalysis also plays a role in drug discovery and can support many active ingredient syntheses at an early stage to build up entire scaffolds in a targeted and preparative manner. Recent progress in recruiting new enzymes by genome mining and screening or adapting their substrate, as well as product scope, by protein engineering has made biocatalysts a competitive tool applied in academic and industrial spheres.

Catalytically Active Inclusion Bodies─Benchmarking and Application in Flow Chemistry.

In industries, enzymes are often immobilized to obtain stable preparations that can be utilized in batch and flow processes. In contrast to traditional immobilization methods that rely on carrier binding, various immobilization strategies have been recently presented that enable the simultaneous production and in vivo immobilization of enzymes. Catalytically active inclusion bodies (CatIBs) are a promising example for such in vivo enzyme immobilizates.

Optimized prodigiosin production with Pseudomonas putida KT2440 using parallelized noninvasive online monitoring.

The red pigment prodigiosin is of high pharmaceutical interest, due to its potential applications as an antitumor drug and antibiotic agent. As previously demonstrated, Pseudomonas putida KT2440 is a suitable host for prodigiosin production, as it exhibits high tolerance toward the antimicrobial properties of prodigiosin. So far, prodigiosin concentrations of up to 94 mg/L have been achieved in shake flask cultivations.

Optochemical Control of Bacterial Gene Expression: Novel Photocaged Compounds for Different Promoter Systems.

Photocaged compounds are applied for implementing precise, optochemical control of gene expression in bacteria. To broaden the scope of UV-light-responsive inducer molecules, six photocaged carbohydrates were synthesized and photochemically characterized, with the absorption exhibiting a red-shift. Their differing linkage through ether, carbonate, and carbamate bonds revealed that carbonate and carbamate bonds are convenient.

Biocatalytic C3-Indole Methylation-A Useful Tool for the Natural-Product-Inspired Stereoselective Synthesis of Pyrroloindoles.

Enantioselective synthesis of bioactive compounds bearing a pyrroloindole framework is often laborious. In contrast, there are several S-adenosyl methionine (SAM)-dependent methyl transferases known for stereo- and regioselective methylation at the C3 position of various indoles, directly leading to the formation of the desired pyrroloindole moiety. Herein, the SAM-dependent methyl transferase PsmD from Streptomyces griseofuscus, a key enzyme in the biosynthesis of physostigmine, is characterized in detail.

Mutasynthesis of Physostigmines in .

The alkaloid physostigmine is an approved anticholinergic drug and an important lead structure for the development of novel therapeutics. Using a complementary approach that merged chemical synthesis with pathway refactoring, we produced a series of physostigmine analogues with altered specificity and toxicity profiles in the heterologous host . The compounds that were generated by applying a simple feeding strategy include the promising drug candidate phenserine, which was previously accessible only by total synthesis.

Lewis Base-Brønsted Acid-Enzyme Catalysis in Enantioselective Multistep One-Pot Syntheses.

Establishing one-pot, multi-step protocols combining different types of catalysts is one important goal for increasing efficiency in modern organic synthesis. In particular, the high potential of biocatalysts still needs to be harvested. Based on an in-depth mechanistic investigation of a new organocatalytic protocol employing two catalysts {1,4-diazabicyclo[2.

Prodigiosin Sensitizes Sensitive and Resistant Urothelial Carcinoma Cells to Cisplatin Treatment.

Cisplatin-based treatment is the standard of care therapy for urothelial carcinomas. However, complex cisplatin resistance mechanisms limit the success of this approach. Both apoptosis and autophagy have been shown to contribute to this resistance.

Understanding substrate binding and the role of gatekeeping residues in PigC access tunnels.

Semi-rational redesign of the substrate binding pocket and access tunnels of prodigiosin ligase PigC enhanced the catalytic efficiency in the synthesis of pyrrolic anti-cancer agents more than 45 times. A molecular understanding was gained on residues V333 and T334 relevant to substrate binding and translocation of small pyrroles through PigC access tunnels.