Abstract Many natural products contain the hexahydropyrrolo[2, 3- b ]indole (HPI) framework. HPI containing chemicals exhibit various biological activities and distinguishable structural arrangement. This complexity renders chemical synthesis very challenging. Here, through investigating biosynthesis of a naturally occurring C 3 -aryl HPI, naseseazine (NAS-C), we identify P450 enzyme (NascB) reveal that NascB catalyzes radical cascade reaction to form intramolecular intermolecular...

The penM and pntM genes from the pentalenolactone biosynthetic gene clusters of Streptomyces exfoliatus UC5319 arenae TÜ469 were predicted to encode orthologous cytochrome P450s, CYP161C3 CYP161C2, responsible for final step in biosynthesis sesquiterpenoid antibiotic (1). Synthetic optimized expression Escherichia coli used obtain recombinant PenM PntM, each carrying an N-terminal His6-tag. Both proteins showed typical reduced-CO UV maxima at 450 nm, bound substrate, F (4), with KD values...

The pentalenolactone biosynthetic gene clusters have been cloned and sequenced from two known producers of the sesquiterpenoid antibiotic pentalenolactone, Streptomyces exfoliatus UC5319 arenae TÜ469. recombinant enzymes PenE PntE, S. arenae, respectively, catalyze flavin-dependent Baeyer-Villiger oxidation 1-deoxy-11-oxopentalenic acid (7) to D (8). Recombinant PenD, PntD, PtlD, latter avermitilis, each Fe(2+)-α-ketoglutarate-dependent (8) E (15) F (16). Incubation or PtlD with isomeric...

Huang Qin (root of Scutellaria baicalensis) is a widely used herb in different countries for adjuvant therapy inflammation, diabetes, hypertension, kinds cancer and virus related diseases. Baicalin the main flavonoid this has been extensively studied 30 years. The angiogenic effect extract baicalin was found 13 years ago, however, results were controversial with pro-angiogenic some studies anti-angiogenic others. In paper, baicalin, its aglycone form baicalein aqueous chick embryo...

Summary Antibiotic resistance in Helicobacter pylori has been growing worldwide with current treatment regimens. Development of new compounds for H. infections is urgently required to achieve a successful eradication therapy the future. Armeniaspirols, novel class natural products isolated from Streptomyces armeniacus , have previously identified as antibacterial agents against Gram‐positive pathogens. In this study, we found that armeniaspirol A (ARM1) exhibited potent activity including...

Armeniaspirols (1–3) are potent antibiotics against Gram-positive pathogens. Through a biosynthetic investigation, we identified four enzymes involved in the structural modification of 1–3. Manipulation their activity led to generation 4–6 and nine novel analogues, 7–15. Bioactivity assessments revealed that pyrrole chloro group methyl important for antimicrobial activities armeniaspirols, which lays foundation future structure optimization mechanism action studies armeniaspirols.

The orthologous penR and pntR genes from the pentalenolactone biosynthetic gene clusters of Streptomyces exfoliatus UC5319 S. arenae TÜ469, respectively, were predicted to encode MarR/SlyA family transcriptional regulators, responsible for regulation biosynthesis sesquiterpenoid antibiotic pentalenolactone. intrinsic target DNA sequences small molecule ligands purified recombinant PenR PntR identified by electrophoretic mobility shift assays. bound both penR-gapN penM-penH intergenic...

SUMMARY Benzylisoquinoline alkaloids (BIAs) are a class of plant secondary metabolites with great pharmacological value. Their biosynthetic pathways have been extensively elucidated in the species from Ranunculales order, such as poppy and Coptis japonica , which methylation events play central roles directly responsible for BIA chemodiversity. Here, we combined quantitative profiling transcriptomic analyses to identify novel methyltransferases (MTs) Liriodendron chinense basal angiosperm...

Dark brown haloes of melanin around colonies are an easily visualized phenotype displayed by many Streptomyces strains harboring plasmid pIJ702 carrying the melC operon antibioticus IMRU3270. Spontaneous melanin-negative mutants occur with a frequency ca. 1%, and often mutation occurs in operon, which removes BglII site as part inverted repeat. Other mutations seem to spontaneously lividans, resulting white from intact, melanin-producing can be isolated introduction into new host. S....

Objective: To investigate the prevalence and resistance changes of carbapenem-resistant Enterobacteriaceae (CRE) strains isolated from children patients Chinese Bacterial Resistance Surveillance Network (CHINET) 2005 to 2017. Methods: Antimicrobial susceptibility testing was carried out by disk diffusion method (KB method) automated systems. Results were analyzed according Clinical Laboratory Standards Institute (CLSI) 2017 edition standards. Results: Among 4 481 CRE clinical strains,...

In the biosynthesis of pentalenolactone (1), PenE and PntE, orthologous proteins from Streptomyces exfoliatus S. arenae, respectively, catalyze flavin-dependent Baeyer–Villiger oxidation 1-deoxy-11-oxopentalenic acid (4) to lactone D (5), in which less-substituted methylene carbon has migrated. By contrast, paralogous PtlE enzyme avermitilis catalyzes 4 neopentalenolactone (6), more substituted methane substitution undergone migration. We report design analysis 13 single multiple mutants...

It is important to improve the production of bioactive secondary products for drug development. The Escherichia coli—Streptomyces shuttle vector pSET152 and its derived pIB139 containing a strong constitutive promoter ermEp* are commonly used as integrative vectors in actinomycetes. Four new carrying kasOp*, hrdBp, SCO5768p, SP44, respectively, were constructed proven be functional different mangrove-derived Streptomyces host strains by using kanamycin resistance gene neo reporter. Some...

Pentalenolactone is a microbial sesquiterpenoid with antibiotic activity. Its biosynthetic pathway was elucidated by combination of genetic and biochemical characterizations all genes involved. For the related neopentalenoketolactone gene cluster from Streptomyces avermitilis, an α-ketoglutarate-dependent mononuclear nonheme iron enzyme, PtlD, proposed to catalyze both desaturation olefin epoxidation reactions. Yet, these activities remained be validated in vitro evidence. In this report, we...

The selective incorporation of new-to-nature extender units into polyketide synthesis is a highly effective way to engineer their carbon scaffolds. Currently, most atypical are biosynthesized via reductive carboxylation α,β-unsaturated thioesters catalyzed by crotonyl-CoA reductase/carboxylases or thioesterification malonates malonyl-CoA ligases followed epimerase enantiomerization. In this study, we identified an unusual β-subunit (Arm13) the acyl-CoA carboxylase (ACCase) from biosynthesis...

Air-ground collaborative robots have shown great potential in the field of fire and rescue, which can quickly respond to rescue needs improve efficiency task execution. Mapping navigation, as key foundation for air-ground achieve efficient execution, attracted a deal attention. This growing interest robot mapping navigation is conducive improving intelligence but there has been no comprehensive investigation this highlight their strengths. In paper, we present systematic review...

DepR, a LysR-type transcriptional regulator encoded by the last gene of putative min operon (orf21-20-19-depR) located at downstream region anticancer agent FK228 biosynthetic cluster in Chromobacterium violaceum No. 968, positively regulates biosynthesis FK228. In this work, mechanism underlining positive regulation was probed multiple approaches. Electrophoretic mobility shift assay (EMSA) and DNase I footprinting (DIFA) identified conserved 35-nt DNA segment orf21-orf22 intergenic where...

The goal of this research is to explore the anticancer effects α -enolase targeted peptide (ETP) modified oxaliplatin-loaded Fe 3 O 4 nanoparticles (ETP-PtFe NPs) and their synthesis, characterization, biological function, characterization on breast cancer. ETP-PtFe NPs were studied using transmission electron microscopy, dynamic light scattering, zeta potential analysis, ultraviolet absorption spectroscopy. Nanocomplexes’ cytotoxicity cell cycle distribution utilizing flow cytometry tests...